COMPUTER SCIENCE
Addition Structured Hash and its Applications Stefan Crnojević Supervisor: Mateja Opačić Regional Centre for Talented Youth Belgrade II, Serbia, scrnojevic@yahoo.com
1
Introduction
Modern cryptographic one-way hash functions usually play a huge role in our everyday communication on any type of a secure network. Security of every cryptosystem depends on the security of all its primitives equally, one of which is highly likely to be a cryptographic one-way hash function. Even after a lot of extensive research, we still aren't able to make a comprehensive method to prove if such functions are secure or not, so each one must be studied intensively in order to reveal its shortcomings. Therefore, diversity in new approaches in the design, and the structure of the designed itself is needed in order to preserve the security of everyday communication. The main aim of this project is to try to present such contribution.
2
The Contribution
The hash functions mentioned take an input of arbitrary length and the output of fixed length in the interval from 160 to 512 bits, or even more due to the potential bruteforce attacks. Apart from having to work efficiently for any given input, cryptographic hash functions must provide that it is infeasible to produce the original data from the given hash. This property, along with the property of infeasibility of changing the input in any way and not altering the hash, defines the first pre-image resistance. The function I created, named Addition Structured Hash, apart from passing truth table tests which these properties must imply on, does even more. It can output an arbitrary size hash for any given input, while at the same time preserving its preimage resistances.
3
while testing, the great attention is dedicated to testing the balancedness, regularity, and especially the nonlinearity of the small compression function’s truth table. This is a sound approach if these properties are preserved when the input-output space is increased, as it is the case here. The mentioned properties are implied by the pre-image resistance and, given no structural flaws they are supposed to imply the pre-image resistance. The original structure of the compression function came from the linear addition operation, which highly modified stream can be noticed in the main part of the algorithm in fig. 1. The mapping is from {0,1}4n to {0,1}n, where n ∈ ℕ \ {1, 2}. Therefore, the input is divided into four equal streams, P1 (not marked) being the hash state and the other three being the input streams, marked P2, P3 and P4. The first main nonlinear step of the compression function (marked ρ i ) is the replacement of the bitwise AND operation of the original addition algorithm with 4-to-1 function of a different probability distribution that, apart from one bit of P1 and one bit of P2, also takes the corresponding bits of P3 and P4 of the same index as a part of its input. The second one is the overwriting of the first bit of P1 with the current totalXOR of all the bits in P1 (marked tx). The rest of the modifications are added to preserve the great statistical properties of the original addition algorithm and to ensure even higher nonlinearity after the two main nonlinear steps.
The Inner Workings
The modern cryptographic one-way hash functions are made of two parts: the compression function and the extender function. The compression function is a one-way function that works with the inputs and outputs of fixed and smaller size and should be pre-image resistant, while the extender is made to preserve its properties. My function uses a classical extender, utilized by all the functions that are considered to be secure today: the Merkle-Damgård extender. Nevertheless, the approach I have taken to create the compression function is entirely new and original. The main cause of the arbitrary digest hash function is the possibility of a new approach in the function testing. Namely, if the input-output space is small enough, its properties can be measured more precisely. Therefore,
Fig. 1, the ASH compression function
4
Conclusion
The space complexity of ASH is minimal – only the input storage is required in practice. The running time is faster than that of adding four n-bit numbers. Therefore, a large number of applications is possible in the mentioned realtime cryptosystems apart from the other usages. Besides the algorithm itself, the basic approach and the idea of the
algorithm’s new structure are a great contribution as well for some other new contributions and ideas may arise from them.
Optical Hydrocarbons’ chemical formula recognition Tamara Stanković
tjstankovic@gmail.com Regional Centre for Talented Youth Nis
1 Introduction
Determining character connection.
Chemical graph theory is a branch of mathematics which models molecules in order to gain better insight into the physical, chemical and biological properties of the compounds and their better approximation. Digitalization is translating analog signal into digital data. In order to make digitalization faster and more precise, many optical character recognition algorithms have been developed and one of them has been used in this paper. Purpose of this paper is finding and describing an algorithm for optical Hydrocarbons’ chemical formula recognition of given photo. Therefore, this is optical graph recognition problem.
It should be determined which letters are connected (and how). Two letters are connected by a line which is closest to them. So, for each line, it can be found which two letters it connects and then construct adjacency matrix of molecule graph.
Determining the molecule.
2 Methods
Using the adjacency matrix in molecule graph, it should be concluded which graph is in the photo. Properties of chemical compounds and value of Wiener index can give needed information. Value of Wiener index can be calculated using Floyd-Warshall algorithm and compared with constants for each molecule. That way, molecule from the photo has been recognized.
An algorithm for optical Hydrocarbons’ chemical formula recognition of given photo has a couple of stages.
3 Results
Editing the photo. In order to represent photo on the computer, it has to be digitalized. First, photo which is in RGB model, should be translated into grayscale photo. For each pixel, values of red, green and blue channel can be determined and simple formula đ?‘”đ?‘&#x;đ?‘’đ?‘Ś = 0.21∙đ?‘&#x;đ?‘’đ?‘‘ +0.71∙đ?‘”đ?‘&#x;đ?‘’đ?‘’đ?‘›+0.07∙đ?‘?đ?‘™đ?‘˘đ?‘’ can be used to calculate grayscale value of that pixel. Then, photo should be converted into binary image. Otsu method has been used to make binary photo.
Extracting and editing characters and lines.
For the purpose of this paper, application HemijskeFormule has been written using programming language Java and all the results have been made using this application. Application has been tested on 150 photos. Precision has been analyzed in certain parameters such as: type of chemical formula, number of C-atoms in the molecule, type of chemical bond, ect. Recognition has a precision of 93% for molecule formulas and 71% for structural formulas. Precision also depends on number of C-atoms in the molecule, and type of chemical bond. Total precision of an application is 80%.
The goal is to find all connected pieces in the matrix of the photo, which represent some character or a line. DFS (Depth-First Search) algorithm for graph search is used to do it. Components then should be reduced in order to be 20x20.
4 Conclusion
Character and line recognition.
Dejan Ĺ˝ivković. Osnove dizajna i analize algoritama. RaÄ?unarski fakultet Beograd i CET, Beograd 2007. Andrew Ng. Machine Learning. Stanford University, Coursera 2013.
Neural network, a machine learning algorithm, has been used for character recognition. For each component, it is determined if it was a character (C, H and digits 0-9) or a line. Neural network has been implemented using applicative software Neuroph. For each component, neural network can determine which character best suits that component, whereas lines are components that are not letters or digits.
The obtained results are satisfying and represent progress in optical graph recognition.
5 References
Nobuyuki Otsu. A Threshold Selection Method from Gray-Level Histograms. IEEE Transaction on Systems, Man, and Cybernetics, 1979.
Application of texture recognition using three-dimensional textons to iris biometric authentication Lazar Mitrović Center for talented youth Belgrade II, Belgrade, lazanet96@gmail.com
1. Introduction The iris is a muscular circular structure in the eye. It is responsible for controlling the diameter and size of the pupil – so as the amount of light reaching the retina. Color of iris determined by more than one gene, but iris pattern is developed in uterus in period from three to eight months after conception. It is distinctive by each iris and represents different positions, numbers and sizes of iris arteries. Iris pattern is same regardless of age and it is impossible to surgically modify it without risking loss of vision and as number of possible pattern combinations is several times greater than whole world population, all these things make iris good candidate for biometric authentication.
Figure 1 - Efficiency of different filter banks (training set - 15 irises).
2. Method Most popular method for iris recognition is one suggested by J.Daughman. In this research we study usability and performance of Iris recognition technique based on texture recognition algorithm by Thomas Leung and Jitendra Malik. Advantage of this method is that it uses entire filter bank, so it produces more features for comparison. This is the first attempt of this kind of application for that algorithm. Implementation is done in MatLab environment and combined with iris normalization by converting cartesian to polar coordinates, and produces fair results comparing to conventional method. Also multiple different parameters for number of clusters in K – Means are tested to select one that is most appropriate.
Figure 2 - Efficiency of different filter banks (training set - 15 irises).
4. Conclusion Implemented method is shown to be usable for iris recognition with over 72% success rate. However, we also saw that this method is not as precise as Daugman’s because of false positives on badly defocused examples. This rate could be increased by using higher resolution samples in controlled environment, different threshold for histogram comparison and automatic segmentation algorithm with eyelashes exclusion.
References
Image 1 – Segmented and normalised iris used in implementation
3. Results Algorithm is trained on 20 classes (different irises) with 1020 iris pictures for each subject and testing was done on 65 randomly selected irises. Also S, MR8 and LM filter banks were used. Collected results are shown on Figures 1 and 2.
[1.] An Improved Approach for IRIS Authentication System by Using Daugman’s Rubber Sheet Model, Segmentation, Normalization and RSA Security Algorithm, Mininath Raosaheb Bendre, Sandip Ashok Shivarkar [2.] How Iris Recognition Works, John Daugman, PhD, OBE [3.] Representing and Recognizing the Visual Appearance of Materials using Three-dimensional Textons, Thomas Leung, Jitendra Malik
Implementation of RTU and SCADA system for temperature measurement Aleksandar Spasojevic Center for talented youth Belgrade II, Belgrade, acika20@gmail.com
1. Introduction In this work it is shown that is possible to realize relative cheap RTU which is connected with 5 digital sensors Dallas Maxim DS1820 over long wires about 100m . Also goal was RTU to communicate with PC and so simple SCADA is made with graph plotting possibilities and also alarm monitoring. In work is implemented appropriate hardware and software for microcontroller and on PC side programming was done in C++ Builder . The investigation is resulted in device which has low price and suitable performance and found its application in temperature data acquisition in sawdust heating system .
Graph 2 – Temperature in Hospital.
2. Method Main purpose of this system is to measure temperature in several different points ( up to 5 ) at a distance about 100m from particular sensor. Microcontroller ATMEL Atmega 8515 receives data from sensors and send it to PC via serial RS232. Programmed software change received bytes to measured temperatures. User also can set alarm which alert when temperature is over or under line. Also, user receives data via Internet which are used for drawing graph. I used this for measuring temperature in our Hospital in Krupanj. On 4th December 2013 I set sensors at 5:00 AM.
Gra ph 3 – Temperature on entry installation.
Gra ph 4 – Temperature on exit installation.
3. Results At 12 o’clock I got results for last 7 hours. On graphs are shown outside temperature, temperature in Hospital, temperature on entry installation, temperature on exit installation and distinction of temperature on entry and exit installation. Graph 5 – Distinction of temperature on entry and exit installation.
4. Conclusion This is very cheap system, and on this graphs it is shown accuracy of this system. Graph 5 shows that how much power is used for heating up Hospital for every hour. Graph 1 – Outside temperature.
Even on 100m there is no need for signal conditioning treatment.
References [1] Dallas Maxim DS1820 High Precision 1-wire digital thermometer [2] Borland C++ Developer’s guide
ENVIROMENTAL SCIENCE
GEOPOLYMERS AND THEIR APPLICATION IN FILTRATION OF HEAVY METALS FROM WATER JOVANA KARANOVIĆ GLASINAČKA 11
INTRODUCTION Water is the most important element of life. Water quality can be defined as the suitability of water for a particular use. Water situation is deteriorating due to the fact that all the available water resources are polluted simultaneously.
C(mg/l)
Cu
Fe
C0
2.13
2.17
C₁
1.98
1.87
C₂
1.56
1.56
C₃
1.48
1.24
C₄
0.78
0.78
Table 2:.Concentrations of copper and iron Based on the received results the effect of immobilization was calculated. Picture 1: Different geopolymers, depending on the ratio of silicon and aluminum
100 50
Heavy metals usually get into the water through industrial wastewater. Geopolymers are threedimensional synthetic aluminosilicate. These are inorganic, solid, stable and non-flammable materials . When the ratio of Si / Al ≈2 the geopolymer can be used as a material for filtration.
0 ɳ₁
ɳ₂
ɳ₃
Table 3.Effect of immobilization of the four samples of iron and copper
CONCLUSION METHOD OF OPERATION Dissolution of copper and iron in water with concentration of 0.5 mol / dm ³, served as a sample of contaminated water. In the four glasses were measured 0.05g of different geopolymers: 100% metakaolin; 90% of metakaloin and 10% of diatomaceous earth; 80% of metakaloin and 20% diatomaceous earth; 70% of metakaloin and 30% of diatomaceous earth . To each glass was added 20ml dissolution. After half an hour of sedimentation, dissolutions were filtered, and poured in four vial. In the fifth, referent vial was poured starting dissolution. All the vials were sent to be analyzed by Atomic Absorption Spectrometry in order to determine heavy metal concentrations.
It was concluded that geopolymers which consisted of 70% metakaolin and 30% of diatomaceous earth, had the best filtration capacity. With this experiment it was proven that geopolymers can be used for removal of heavy metals from contaminated water. This is very important, since the geopolymers are natural materials, which have no subsequent adverse effects. Geopolymers with collected metals within itself can be recycled and used for roads construction etc.
LITERATURE
RESULTS
[1 ]J. Baras, R. Petrović; Zagađivanje i zaštita vode: Mere zaštite voda i kontrola ispuštanja otpadnih voda u zakonodavstvu Republike Srbije, Beograd (2009)
Using Atomic Absorption Spectrometry, concentrations of copper and iron were obtained for all four glasses.
[2] M. Mirković, Skripta za Vinčine naučionice:Da li želiš da znaš koji su to neorganski materijali nazapaljivi pri visokim temperaturama
ɳ₄
PRODUCTION OF HYDROGEN USING ALKALI ELEKTROLYSIS-ENERGYSAVING USING IONICACTIVATORS Filip Bošković Zemunska gimnazija, Zemun, filipbos26@gmail.com temperatures: a) basic electrolitand b)ionic activatorbased othe complex of [Co (en) 3] Cl3 inthe basic electrolyte. Chart 1. The dependence of the the energy consumption of
1. The purpose of the investigation If the price of crude oil, which is growing rapidly in recent years, is any indicator, it is clear that we are at the beginning of the energy crisis, and we witness the end of cheap and abundant energy.Hydrogen is an energy medium of the future, which will probably replace slowly disappearing, fossil fuels.Its use does not pollute the environment as a product of its use for energy, water.Development in the field of electrolysis, leading to the reduction of energy consumption in the production of hydrogen.The aim of the research is to examine the possibilities of saving energy during electrolytic hydrogen separation from alkaline solutions by adding so-called. ion activators in the electrolyte.
the current density at different temperatures (6M KOH)
2. Methods of the investigation In this experiment cobalt complex was examined, tris (ethylenediamine) cobalt (III) ion, as the ionic activator.The apparatus made at the "Vinca" was used, which consists of electrolytic cells, galvanostat, specially designed containers to capture the separated hydrogen, system for temperature maintenance and measuring devices.To maintain the desired tempterature a water thermostat was used.Both electrodes were made of nickel. The experiments were carried out so that using a galvanostat to task specific current, for which then measures the voltage and time separation.During the work 6M KOH was used as the basic electrolyte, and examination consumption of energy were performed by adjusting the electric current and the temperature, first in the solution of basic electrolyte and then adding the ionic activators to the basic electrolyte solution.SEM was used for obtaining the images of electrodes (before and after the electrolysis process).
3. Results The
consumed
formula Q
energy
was
calculated
by
the
= U ⋅ I ⋅ t . The results will be presented
graphically as Q = f (j) i Q = f (j,T), where is j current density (j = I/S, S represents the total area of the electrode).Using the results of measurements graphics were done, depending on the energy consumption per 1 mol of electrolytically separated hydrogen on Ni cathode, of the current density at different
Chart 2. The dependence of the the energy consumption of the current density at different temperatures(6M KOH+ionic activator) It can be seen that the electricity consumption increases with increasing of the current density of the basic electrolyte with and without ionic activators. At higher temperatures, electricity consumption decreases, and therefore waslowest energy at a temperature of 700C (343K). When adding ionic activators in the basic electrolyte solution electricity consumption drops significantlyand that was proved the hypothesis presented in the paper.SEM images of coating of the electrode after electrolysis showed nodular structure of sediment greater active surface area compared to pure nickel electrode.
4. Conclusion Showed that the total energy of the electrolysis process decreases with increasing temperature. For higher current density, power consumption is higher. The application of energy obtained per mole of hydrogen reduced by 11% with the addition of ionic activators compared with conventional electrolyte. During the in situ use of ionic activators produced a nice black deposit on the surface of Ni cathode, which has a very developed area with uniformly distributed pores and a large number of possible active sites.
Biodiversity of cave world in Serbia and the impact of tourism planning commercialization of speleological objects Irena Gorjanc Kakanjska 2, flat 4, Rakovica 11060, Belgrade entrance to Lazareva cave caving formations were 1. Introduction destroyed , the cave microclimate disrupted and the Development of caving as a multidisciplinary habitat of relict and endemic species destroyed. science in the last two hundred years has enabled many new discoveries in the field of geomorphology , stratigraphy , biology, hydrology, even history. Her progress has also opened up possibilities for wide number of people to visit caves and their use for tourism purposes. The aim of this study was to objectively consider the consequnces of mass commercialization of caves in Serbia , adhering to the undisputed educational and possible financial effects and to point out the dangers to biodiversity and the cave world heritage that may arise from inadequate planning .
2. Method Data on the biodiversity of individual objects was analyzed from the references, in the period of discovering the speleological objects, and later during the development and commercial exploitation. Finding and processing data from literature was accompanied by a tour of caves for photodocumentation of their condition.
Picture 3-Rubbish deep in the cave
4. Conclusion Unfortunately, the negative impact on biodiversity is undisputed and particularly disastrous. The only solution is to approach the tourist arrangement on a very restrictive way. When approaching to equip it has to be done with the constant monitoring (temperature, humidity, chemical and physical properties of soil, water (especially pH, dissolved oxygen, conductivity), the atmosphere, the brightness (lux), biodiversity). Species whose survival we threaten deserve at least a sign at the entrance to the cave, which warn about their existence.
5. References
Picture 1- The entrance To Rćanska cave, not regulated
Picture 2-The entrance to Rćanska cave, regulated
3. Results The survey results clearly indicate degeneration and withdrawal of cave fauna, in some cases the complete extinction of species, also the emergence of non-native plant and animal species are found in many objects. The equipment of Resavska cave began in 1971 . Lighting was done by regular tungsten lighting which in the next 20 years led to the overgrowth of lower plants , drying of rock and cave ornaments near the lightes. In Lazar's Cave , concreting and electrification , led to development of non-native "lapmflora" and because of the infrastructure planning in the near-by cave environment, there was a mixing of surface and underground water , also a multiple increase in the concentration of heavy metals. Extending the
1. S. Mikšić, Characteristics of karst fauna (1979) Ništru "oslobođenje" of Sarajevo 2. T. Slišković stratigraphic and paleontological studies of cave deposits in Bosnia and Herzegovina (1979) Ništru "oslobođenje" of Sarajevo 3. J. Gunn Encyclopedia of karst science (2003), Routledge, London 4. Srbijašume Management plan for natural monuments "Lazarev Canyon" for the period 20112020, (2000) Official Gazette of RS No. 16/2000 5. V. Stevanovic, B. Stevanovic Basic climatic, geological and pedological factors of biodiversity in terrestrial ecosystems of Yugoslavia (1995) p. 75-115 Ekolobri, Faculty of Biology, Belgrade 6. Predrag Đurović Speleological atlas of Serbia (1999) Geographical Institute “Jovan Cvijić" SANU, Belgrade
Landfill Vinca - problems and the landfill’s potential Nikola Tepic, nikola.tepic3bg@yahoo.com Third Belgrade Grammar School, Center for talented Youth Belgrade II
1. Introduction Vinca Landfill is located in the north- eastern part of the city. It is the only official landfill where is disposed all waste of Belgrade's population. However, apart from Vinca, there is a large number of illegal dumps, especially in suburban municipalities, due to lack of machinery and manpower and/or rare of relating waste, or lack of resources. All of these lead to the same. Utility companies clean these illegal dumps, depending on accessibility and other circumstances. However, the landfill Vinca is still the primary problem of Belgrade, because it does not only affect the local population , but also the entire region of Serbia and other towns downstream of the Danube. Due to growing population and an increase in industrial production and consumption, there is an increasing amount of waste, which in ecological terms lead to increased pollution.
2. Methods Used data is primarily collected in cooperation with the Serbian Environmental Protectian Agency and the Department of Environment and Ecology, as well as other organizations and institutes. Processing the data, my goal was to spot the amount of pollution in general, as well as finding some solutions to this situation, which could be set up as a pilot project at first.
20%, followed by plastics, which account for its share of over 15%, a glass and fine materials with less than 10 %... One of the most interesting fact is that diapers account for nearly 4%. The study area was observed following heavy metals in high concentration ranges (Cu , Pb and Zn). The sources of these heavy metals are: metal packages, aluminum waste, pesticides, fertilizers, organic waste, ash... ). There were sampling a water of the Danube at several locations in Belgrade and it was shown that the water quality is the most polluted in Vinca and Smederevo (Category IV ) as a result of heavy metals. Development and urbanization of cities lead to a growing number of population, which requires the proper treatment of urban and industrial waste. As one of the solutions, I would suggest building a waste sorting center at the landfill site, which would sort newcomers waste and waste that is already on the landfill. After sorting it, it would be sold to recycling centers. Development of sorting center, of course, requires a large investments, but they are quite minimal compared to the revenues that would be generated from newcomers waste and the waste which is already on landfill. Of course, all this could be firstly examined in the market as a pilot project, where the sorting would have been performed manually, using manpower, and later on, if it turns out to be an excellent project, it could be went on with investments in equipment and logistics.
The amount and composition of waste is measured by the standard procedure, which already exists and which is used in the utility company - according to the number of vehicles that serve the citizens of Belgrade ( 350-400 vehicles) and their sourcing power. Picture 2 - Place packages sorted waste into trucks for disposal at recycling centers
4. Conclusion Picture 1 – Measuring the weight of loaded truck before extradition
In order to estimate the quantity of heavy metals in the soil of the landfill, it was used a method which consist of taking 3 samples in vertical sidesection of the land beneath it – in depth(s) of: (I) 0-10 cm, (II) 10-20 cm, (III) more than 20 cm. Samples were taken under the waste material that is disposed at the site for at least about 12 months earlier.
Belgrade is a great city, and these kind of projects could be implemented in other cities and municipalities in Serbia. Advantages: new jobs, net profit, costs almost the same as without the Sorting Centers. The monthly income of over € 2 million. Disadvantages: price drop of the waste materials.
5. References 1.
3. Results 2.
By analyzing the collected data, there are the following results. The largest share of waste, of Belgrade population, has biodegradable waste and garden waste, totaling more than 35%, followed by further paper and paperboard with
3. 4.
Serbian Environmental Protection Agency, FERTILITY AND THE PRESENCE OF HAZARDOUS AND HARMFUL SUBSTANCES IN SOIL OF CENTRAL SERBIA, Belgrade, 2009. Institute of Public Health, Regional Environmental Center, Belgrade City Administration, QUALITY ENVIRONMENT OF BELGRADE IN 2008, 2009, 2010TH, Belgrade, 2008,2009,2010. www.sepa.gov.rs www.gradskacistoca.rs
Picture 3 - Scheme of treatment of waste – Sorting Center
POSSIBILITIES OF WASTE WATER REUSE IN HOMES OF ČUKARICA MUNICIPALLITY Jovan Mitić Center for Talented Youth Belgrade II, Belgrade, Joxy97@yahoo.com
2. Method The basic method of working on this project was collecting information over commercial graywater systems and mean water consumption in homes. This information gave approximated results of consumption, cost-effectiveness and environmental impact. In this chapter, graywater systems characteristics were determined as well as price of €80 and water use during activities that produce graywater.
3. Results and Conclusion Practical use of theese systems was researched on and coclusion is that they would be small enough to fit any middle-class bathroom while the tank would always have enugh water to provide to toiltet tank (Chart 1.). If famillies invested in this project, cost-effectiveness would be shown in Chart 2. On the other hand, if the Government invested in this project, and implemented taxes for all saved water with theese systems, citizens' budget wouldn't change, there would be more work (production of graywater systems) and ot would pay off more quckly than if famillies invested in this project by themselves. The environmental influence would be outstanding.
60 50 40 30 20 10 0 6:00 7:30 9:00 10:30 12:00 13:30 15:00 16:30 18:00 19:30 21:00 22:30 0:00 1:30 3:00 4:30
T (h)
Chart 1. - Estimated change of water amount in tank during the day (starting with empty) 100 50
Профит (€)
Municipallity of Čukarica is one of the 17 municipallities of Belgrade with 160.000 citizens and the area of 15.650 ha. Irrational water consumption by Čukarica's citizens makes a great influence on environment. This paper is based on fact that enormous amounts of drinking water are used for toilet flushing, gardenning and fire-fighting systems. Nevertheless, more than 90% of irrationally used water, drops on toilet flushing so that this projec is to deal with this exact problem as that is one way to reuse waste water in homes. The main notion is to use graywater for toiltet flushig as theese are type of waste water which does not include feeces and can be purified enough to use again in tiolet flushing. So, the aim of this project is to do a research on graywater systems efficiency and costeffectiveness and propose ways to implement this idea.
V (l)
1. Introduction
0 1
2
3
4
5
6
7
8
9 10 11 12 13
-50 -100
T (године)
Chart 2. - Long-term project’s financial aspect for one home
4. References [1.] Dr. A.S. Patel, Dr. D.L. Shah (2007.): “Water management”, New age international publishers, New Delhi [2.] Ian L. Pepper, Charles P. Gerba, Mark L. Brusseau (2006.): “Environmental and pollution science - second edition”, Academic press publications, Tucson, Arizona [3.] Dr. Anne Maczulak (2010.): “Environmental engineering - Designing a sustainable future”, Facts on file, New York [4.] http://greywateraction.org/faqs/greywater-recycling
HISTORY
Nuremberg, that the death toll was between 500,000 and 700,000.
Abstract The purpose of writing this paper - is the memory of the suffering of the Jews and many others who perished in Nazi concentration camps. I am horrified by the brutality that occurred in the Jasenovac camp and by the dark forces in this period of human history.
Image 1 - Jasenovac The aim of the dissertation - is a kind of rebellion against God's neglect of small man condemned to eternal anonymity and absolute fading in time. The method of operation - for writing this paper relevant historical literature was used, consisting of a multitude of images, documents, legal provisions, etc., that demonstrate the organization itself, the preparation and operation of the camp, as well as the suffering and torture of inmates. Survey Results – Jasenovac was the largest concentration camp in the Independent State of Croatia in the occupied area of Yugoslavia during World War II. Formed in August 1941 in the vicinity of the town of the same name and destroyed by the Ustase (Croatian Revolutionary Movement) in April of 1945. "Work Camp Jasenovac", as it is called by the Croatian state administration, was the place for execution of Serbs, Roms and Jews of all ages, sexes, social, educational and other profiles, as well as the communists, supporters and sympathizers of the Serbs, Roms and Jews . The number of victims has never been accurately determined. The Camp archive was twice destroyed. State Commission of Croatia, founded in 1945, noted in the report of the International Military Tribunal at
Image 2 – Schematic representation of Jasenovac Conclusion - „There’s not a feather that would be able to describe the horrors and terrible atmosphere of Jasenovac. It exceeds every human fantasy. Hell, the Inquisition, the most horrific terror, the like of which has never and nowhere in history been seen, atrocities of wild beasts, the darkest instincts emerging to the surface which never appeared in human history before – a little is said.“[1]
Images 3 – Victims of Jasenovac Literature – Jasenovac concentration camp 1.,2. i 3., Antun Miletić, Beograd. The Vatican and the Jasenovac, Vladimir Dedijer, Beograd
Golgotha immortalized with camera Anastasija Kocić Ulica Druge proleterske brigade 16/6, 18 000 Niš
Introduction On the occasion of the centenary of the World War I outbreak, and in accordance with the testament that warriors for the national liberation left to the descendants so as to foster the unity, creativity and positive human qualities, I wanted to save the images of pain and pride from oblivion- Golgotha immortalized with camera - as well as to remind that the Serbian army was among the first in the world to found the film section at the Supreme Command in Corfu, and to buy the filming equipment. Photographers recorded the war scenes, particularly the withdrawal of the Serbian army through Albania and the great Salonika front breakthrough, so I made an effort to make all these important material available.
Picture 01- The King Petar on the ox car in 1915, retreating through Kosovo and Metohija.
Work method The Internet research, encyclopedia and discussion with the descendants of the participants of the World War I.
The results Photos of the First World War were published at various times and in various newspapers. Some have emerged in the course of the war, along with reports of war correspondents , as well as on allies’ exhibition of war photographs. Some of these images have become a symbol of the suffering in the war, an essential document of that time. Each image can be a novel , short story, poem, film ... Serbian Odyssey ... John Ford once said: "The Serbs have one photo- a film like. There is one photo from WWI in which old King Peter is sitting on the ox car in 1915 while retreating through Kosovo and Metohija. And if this frame could come alive, it would start moving before our eyes as a real movie about the great drama of the Serbian people and its king ". In the World War I the Cinematographic Section of the Supreme Command was established and it gathered photographers, videographers and painters. If we look through the photographs, postcards and illustrations with motives from Serbia or Serbian army dating to the Balkan Wars and World War I, we will find the names of Serbian war photographers and painters, primarily Rista Marjanovic, and then the military priests Rista Sukovic or Vladimir Becić... The name of Samson Chernova is less frequently inscribed though he made perhaps the most images, did a large number of paintings and made several documentaries. Prominent photographers are Rista Marjanovic, Samson Chernov, Vladimir Becić, Dragisa Stojadinovic and Risto Sukovic. The author of the most famous images of the Serbian army in the World War I, including the iconic portrait of scout Dragutin Matic, was Samson Chernov, a Russian photographer and painter .
Picture 02- the portrait of Dragutin Matic “The soldier with the camera is equal as a soldier with a gun!
Conclusion The passage of time takes its toll on these landmarks, a wartime devastation and vandalism of the enemies are destroying these monuments, which their ancestors could not break nor obey. One of the valuable testimonies of their famous epic, created during the wars, authentic and indestructible, will remain as a permanent heritage in rich Serbian history!
Literature
Branibor Debeljković, Stara srpska fotografija, Beograd, 1977;Milanka Todić, Istorija srpske fotografije 1839—1940, Beograd, 1994;Goran Malić, Milan Jovanović fotograf, Beograd, 1997;G. Malić, Slike u srebru : Predistorija i tehničko-tehnološka evolucija fotografije u 19. veku i prvoj polovini 20. veka., Beograd: Fotogram, 2001.Enciklopedija srpskog naroda, Beograd: Zavod za izdavanje udžbenika, 2008. (biografski prilozi o srpskim fotografima).G. Malić, Letopis srpske fotografije 1839— 2008. Beograd : Fotogram, 2009.
The Rule of Despot Djuradj Brankovic 1. Introduction Despot Djuradj Brankovic was the last notable ruler of the Serbian medieval state. He ruled in the times of unstoppable expansion of the Ottoman Empire. His life overlapped with the period of Serbian fall under the authority of the Turks, and therefore, it was a life comprised of struggles and battles for the sake of preserving the unpreservable, taking back the lands and cities that were hard to hold for longer periods of time once regained. Đurađ Branković was skilled in diplomatic negotiations, he cooperated with all of those who were willing to cooperate, he intended to purchase the Despotate’s autonomy, initially by paying 50 000, and later 60 000 ducats annually, as well as by renting territories to his enemies at times. According to medieval customs, he tried to maintain peace by marrying away his daughters - Mara became one of the sultanas of Murat II, Kantakuzina was married for Ulrich II, Count of Celje.
2. The Times of Reign Until the First Fall of the Despotate The beginning of the reign was marked by the building of the city of Smederevo. The new capital was built from 1428 until 1435, constructed in a style of a well fortified medieval city. After the death of despot Stefan, Belgrade was given back to Hungary , whereas Niš, Kragujevac and Golubac were ruled by Murat II. For several decades, the city was Balkan’s political and trade centre, and the castle was a gathering place for Byzantines which, after the Fall of Constantinople and Thessaloniki, lived and worked in the Despotate. He recieved sigils in the rank of a Despotate in July 1429 in Žiča from an envoy of the Byzantine emperor John VIII Palaiologos. His education was based on Byzantine and Christian, Orthodox values, he believed in the immortality of the Byzantine culture and tradition, and he stayed loyal to his beliefs for the rest of his life. He is the only Orthodox ruler who had never sent delegations to the Union convocation, nor had he ever given written consent for unification. He used to, unceasingly, help the monasteries Hilandar and on Mount Athos, Hilandar and Esphigmenou, and he restored and looked after the monasteries in the Despotate. In order to raise the peoples’ spirits, he himself being a devout believer in the strength of the saints, bought, and transported, the bodily remnants of Luke the Evangelist from the sultan. The times until the first siege, that took place in year 1439, are remembered by Djuradj’s efforts to keep a peaceful relationship with the sultan, who being the most powerful man of the time, but also by the belief that it is possible to gather a Christian army which would cease the spread of Turks throughout the Balkan lands. Serbia was still rich and well populated country then, with numerous vilages, cultivated land areas and dense forests. The despot was, thanks to the mines Novo Brdo, Rudnička and Bosanska Srebrenica, and an income of several hundred thousand ducats, the richest Christian ruler on the territory of South-Eastern Europe. The first fall of the Serbian medieval state came after two year desolations of Turkish and Hungarian armies which lead battles on despot’s land, although he didn’t take part in the battles, on either side. The cession of the rich town of Braničevo did not stop Murat’s advancing, and it is due to that that the Serbian people started deserting Serbia and moving to Hungary.
3. The Fall of the Despotate The city of Smederevo fell in August 1439, when the main defender, despot’s eldest son, Grgur, was taken into slavery. Despot’s other son, Stefan had already been held hostage since 1435.
In the time period between the years 1439 and 1444, despot Djuradj resided in the city of Dubrovnik, on his Hungarian property, together with his family and royal household. As a Hungarian baron, he actively took part in the events that followed the change of rulers at the Hungarian throne. In order to regain the Despotate, he decided to strengthen his bonds with Hungary again, to subject himself to young King Vladislav, and eventually, by proper investments and together with eight thousand soldiers, initiate a new attack on Murat II. Led by Janko Hunjadi and despot Djuradj, an army of 33000 men entered Serbia, during early Autumn, and that’s how his military operation started. The despot used the oportunity to start negotiations and finally sign a peace treaty in the Summer of 1444, in which it was stated that the sultan was cessing the lands, together with 24 cities, which he had taken away. He also allowed the return of Djuradj’s blinded sons, Grgur and Stefan.
4. Rebuilding the Despotate Although Serbia had been severly desolated, although many cities had been turned to dust, and people taken to slavery, the despot started to relentlessly fortify and raise cities, renew the mines. He would not lead any more wars against the Turks, but instead, he would be a mediator between Hungary and the Ottoman Empire, as well as between Dubrovnik and Porta. Smederevo was to become the cultural and trade centre of the Balkans. New changes took place after the death of Murat II in 1451. Mehmed the Second’s conquests were unbearable to the despot, and peace was not buyable. After the Fall of Constantinople, Mehmed II began his attack on the Despotate. Although he did not manage to siege Smederevo, the conquest represented the beginning of a complete enslavement of Serbia. In year 1455 the great and rich Novo Brdo fell. In June 1456, the Turkish army attacked Smederevo. After two weeks of siege, the sultan, disappointed by the losses, stopped the siege, and went on to siege Belgrade. Belgrade was defended, but the ruination was extensive, the great victory was followed by a great plague, as well as by the murder of the despot’s son-in-law, Ulrich II, Count of Celje, in the very city. Being wounded himself, the despot did not recover well. He was more than 80 years old, and after half a century of warfare with numerous enemies, on different sides, with no peace established with the sultan who refused to recieve despot’s chieftain, who had been sent out for negotiation purposes, Djuradj Brankovic died on 24 December 1456, in the reduced Despotate, in Smederevo.
5. Conclusion The life of despot Djuradj Brankovic overlapped with the destruction of his country, and the keys of his city were given to Mehmed II by Serbian noblemen on 20 Jun 1459, which is an event that represented the end of the Serbian medieval state. During his long life, in which the situation, the times, nor the later stories, were in his favour, Djuradj Brankovic channeled, just like his uncle, despot Stefan Lazarević, did, all of his physical and intellectual strength towards the preservation of the land, the people and the religion. The life of the Serbian medieval state was prolonged only by the years of reign of the two last Serbian despots.
6. Literature 1. Momčilo Spremić, Đurađ Branković 1427-1456, ZUNS, Belgrade, 2006. 2. Nadežda D. Pavlović, Despot Đurađ Branković and his era, Minerva, Subotica - Belgrade, 1973. 3. The history of Serbian people, 2. tome, Srpska književna zadruga, Belgrade, 1982.
Rashidun Caliphate Andrija Kapetanović Regional Centre for Talented Youth Belgrade II, Serbia, kapetanovicandrija@gmail.com
1
Introduction
The Rashidun caliphate was the first Islamic state. It quickly rose to the rank of a strong and vast medieval empire that stretched on two continents., thus changing the course of history. It also had very significant achievements, especially in science ands religious tolerance.
2
tolerance to a certain extent was implemented, nonMuslims could hold key positions and freely practice their religion, which was very advanced for that time This proved as a very effective way of having a non-rebellious sentiment in their state. The Rashidun Caliphate, was replaced by the Umayyad Caliphate, but, essentially, this represented a continuation of the first, Rashidun Caliphate. I hope that my research will spark interest of scientists and other people for Arab history and culture, which, in my opinion isn't being researched enough.
Methods
This research will focus on how the Arab state emerged from total anarchy into a single and united state under Islam. Secondly, it will need to reveal the factors which caused this and, after conquering new territories, how did the outside culture influence the Arabs. Philip Hitti and his book "The History of the Arabs" will reveal how they managed to achieve this in detail, also giving us information on how the Arabs see and saw these historical events. Miroslav Brandt, a Yugoslav expert on medieval history will reveal us how this happened and influenced the rest of the world on an overall political scale in his work "The medieval age of historical development".
3
Results
The emergence of Islam took a great impact on the Arabs. It managed to unite the Arab society which was in complete anarchy and disorder, where only tribal laws existed. The prophet Muhammad succeeded in uniting a few tribes, after which he engaged in a full scale law with the goal of uniting the tribes in a single state, ruled by Islam. After achieving this, they turned their attention to neighbouring states and invaded them. Philip Hitti shows us that the cause of this was not perhaps lead by the idea of expanding Islam, but of economic reasons and thirst for better life. They quickly conquered a vast space, from North Africa to Central Asia and imposed Islamic rule and law upon these countries. However, they incorporated the administration and tax systems of those countries those land that they conquered, thus making their own rule more effective Having conquered he main centres of Greek culture in Asia, they soon began to use their knowledge in everyday life, ranging from mathematics, to medicine and science and even overcame western medieval medicine in the next centuries. What is particularly interesting is that the Arabs had a very similar system of conquest to the Persians, who had one of the biggest empires in world history. Religous
Rashidun Caliphate at its peak, 654 AD 1
4
Conclusion
The Arabs succeeded in creating an enormous state with the help of Islam, that is united its warring tribes under one faith, allowing them to turn their attention to conquest of new lands. It seems that the conquest was driven by economic reason firstly, not religious as many people thought. After conquering vast spaces of territory, they started to implement their own laws, a practice which wasn't very common for a nation that was nomadic up to that point. The systems which they encountered in their newly-conquered territories proved as a model for their own system, which the Arabs used to a huge extent, thus making their own system more effective. Unlike many nations, they harnessed knowledge from their former enemies and used it to achieve many things, particularly in medicine, mathematics and religious tolerance.
1
http://en.wikipedia.org/wiki/File:Mohammad_adilRashidun-empire-at-its-peak-close.PNG
4 Bibliography: Philip Hitti: "History of Arabs", Veselin Masleša, Sarajevo, 1988. Miroslav Brandt: "The medieval age of historical development", SNL, Zagreb, 1980 http://www.wikipedia.org/
Ravna gora movement as the holder of yugoslav resistance in Second world war Filip Pejković Center for yough talente Belgrade II, Belgrade, filip.pejkovic@yahoo.com
1. The purpose and goal of the research Ridicule and often falsifying history of Ravna Gora movement, which lasted more than seven decades, and the public statements of individuals or groups during the breakup of Yugoslavia, led to the fact that this topic is compromised by the widest public, which resulted in a lack of quality literature. Therefore it was necessary to make a thorough historical analysis with the help of testimony by people of that time, in order to come to a views history of Ravna Gora movement.
2. The applied methods With critical analysis of literature, we tried to avoid all information that are the result of post-war propaganda, ideological opponents, as well as the obvious sympathy of some authors that are diverted from the objective research. It should be noted that the basis for this study were taken two books: ''Ravnogorska istorija'' written by Radovan Kalabić and ''Draža - the death of more than life '' by Pero Simić, but if necessary used chronology, memoirs and other publications. .
3. Results Fundamental research led to the conclusion that members of the Ravna Gora Movement had antipode of that screened during the rule of the socialist regime in Yugoslavia. Although not presented any new information, we've met with a lot unsaid facts about the role of the anti-fascist movement during World War II , but also of his superiors in which we counted the names of exemplary officers, soldiers and host.
4. Conclusion Ravna Gora movement enjoyed the support in allied circles, while the glory of its leaders wrote praises and making films in the United States. However, the major political agreements are this resistance put on the margin of War diplomacy, although his combat not lose intensity. Unfair treatment toward members Ravna Gora movement spanning seven decades, as can be seen from the manner in which they were prosecuted on charges of collaboration with the
occupying forces, deprivation of civil, human and due process rights, and so on. In any case, you can not deny that Ravna Gora movement played a leading role in the fight against the invaders on the territory of the Kingdom of Yugoslavia, since it is the first serious armed uprising began even in the whole of Europe.
5. Literatura 1. Перо Симић, Дража – смрт дужа од живота, Службени гласник, Београд 2012. 2. Мр Радован Калабић, Равногорска историја, ИКП Евро, Париз 1992. 3. Žarko Jokanović, Jovanka Broz: Moj život, moja istina – od rođenja do bolničkih dana, Beograd 2013. 4. Luka Mičeta, Povratak kralja, Laguna, Beograd 2013. 5. Александар Ранковић, Дневничке забелешке, Југословенска књига, Београд 2001. 6. Oto Skorceni, Specijalna misija, Algoritam, Beograd 2009. 7. Hronologija oslobodilačke borbe naroda Jugoslavije 1941-1945, Vojnoistorijski institut, Beograd 1964.
LIFE SCIENCE
Chemical composition of defensive fluids in the millipede Polydesmus collaris from Mt. Avala, Serbia Konstantin Kostić Center for talented youth Belgrade II, Belgrade, kostic.prof@gmail.com
1. Introduction
Compound
Millipedes or Diplopoda are an ancient and one of the widespread group of animals, comprising more than 12,000 species [1]. These arthropods are also known as chemical warriors. Most of the millipedes possess repugnatorial glands (ozadens) on pleurotergites, with different composition of defense secretion depending on the taxonomic group. Most members of the order Polydesmida are known as cyanogenic millipedes due to the production of HCN and cyanogenic compounds [1]. Until now, chemical composition of defensive fluids in millipedes is known in less than 2 % of species [2].
1 2 3 4 5
2.
6 7
Benzaldehde Benzoylnitrile Benzyl methil ketone Benzyl ethil ketone 2-Methil-1,4naphtoquinone Mandelonitrile benzoate Benzoic acid
Rt (min) 6,6 11,1 12,6 16,9 29,4
Relative abundance (%) 55,9 42,3 0,4 1,0 0,1
45,2
0,1
51,9
0,2
Objective
The aim of this work was to determine and identify the chemical components of the defensive secretions from analyzed species, to test for possible interspecies variation of the chemical constituents with previously analyzed forms, and confirm the consistency of cyanogenesis in the member of the order Polydesmida.
3. Materials and methods Specimens of P. collaris were collected in the autumn (September 2013) at Mt. Avala, near Belgrade. Polydesmids were stored in plastic boxes with a layer of litter and soil and kept in the laboratory for a few days. Humidity in the boxes was kept high by spraying water every day. Chemical analyses were performed on an Agilent 7890A GC system. A library search and mass spectral deconvolution and extraction were performed by using NISTAMDIS (Automated Mass Spectral Deconvolution and Identification System) software, ver. 2.64.
4. Results and discussion Analysis of defensive secrets in P. collaris showed presence of eight compounds (seven compounds in Table 1; presence of HCN was confirmed by picric acid test). Two major components were benzaldehyde and benzoylnitrile. No significant difference in the amounts of the components was observed between the sexes in the analysed species. Benzaldehyde and HCN are known as the most common defensive substances in various polydesmids [3], and in analyzed species have allomonal function. 2-Methil-1,4naphtoquinone was detected for the first time within whole order Polydesmida. On the other hand its presence showed specific chemoprofile of analyzed species. Presence of mandelonitrile benzoate in defensive fluids is interesting because it may represent the mechanism that stabilizes mandelonitrile if the specimen is consumed by a predator [4]. Table 1: Chemical composition of the defensive secretions in the Polydesmus collaris C. L. Koch, 1847 analyzed by GCMS.
Figure 1: GC-MS total ion chromatogram of hexane extract of Polydesmus collaris C. L. Koch, 1847. Number of peaks corresponds to the number of compounds in Table 1.
5. Conclusion With the execption of a few noncyanogenic Polydesmida [4] the majority of polydesmoid millipedes are cyanogenic, which was confirmed by this study. Analyzed polydesmids have specific chemoprofile, clearly different from previously analyzed species. Eight detected compounds have allomonal functions, but some of them may also have some antimicrobial or antifungal properities.
References [1] S. Hopkin, H. Read: The Bioilogy of Millipedes. New York, Oxford University Press, (1992), 233pp. [2] O. Eisner, D. Alsop, K. Hicks, J. Meinwald: Defensive secretions of millipedes. Pp. 41. In Bettini (Ed.) Arthropod venoms. Springer Verlag, Heidelberg Berlin (1978). [3] S. Makarov, B. Ćurčić, V. Tešević, M. Jadranin, Lj. Vujisić, S. Ćurčić, B. Mandić, T. Sekulić, B. Mitić: J. Chem Ecol. 35, (2010), 978-982. [4] Y. Kuwahara, N. Shimizu, T. Tanabe: J. Chem. Ecol, 37, (2011), 232-238.
Difference of chemical components in apple and pear tea depending on preparation Milica Buhovac Birčaninova 18, Beograd; migoma@eunet.rs
1. Introduction Apples and pears are among the most widespread fruits in our country, and thanks to their presence in the market throughout the year, as well as the rich content of polyphenolic compounds, they represent a significant source of secondary metabolites in the diet. Apples and pears contain a number of phytochemicals , including phenolic compounds ( flavonoids , anthocyanins , proanthocyanidins , tannins ) . There is a growing interest of researchers to study the phytochemical, because the results showed that they can slow the proliferation of malignant cells , regulate the immune defense system and protect against lipid oxidation( 1,2 ). Epidemiological studies have linked the consumption of apples and pears with a reduced risk of cardiovascular disease, asthma, diabetes, Alzheimer's disease, increasing lung capacity, and weight loss. Besides fresh fruits that is available in our environment generally most of the year, products are also signigicant, and especially dry fruits which are prepared in the form of vitamin drinks, teas. There are two traditional and pharmacopoeia recognized method of preparation of tea, such as infusion and Dekokt. The aim was to see which of the two modes in a better for apples and pears in terms of extraction and conservation of active ingredient that are known to possess beneficial effects on human health.
Results for the proanthocyanidins are similar to the previous ones. Again, the apples were richer with these compounds (infusion 14,34 ± 1,64 or 42,25 ± 0,4 Dekokt mg katehina/100 ml) compared to pears (traces in infusion Dekokt: 11.67 ± 0.18 mg of catechin / 100 ml).
Chart1- Results
4. Conclusion The aim was to see which of the two modes in a better for apples and pears in terms of extraction and conservation of active ingredient that are known to possess beneficial effects on human health. It has been concluded that using Dekokt method, researched phytochemicals were preserved better, and also that apples contain more of them.
2. Methodes
5. Literature
Of grinded fruit (apples and pears) first was made tea using methods of infusion and Dekokt. Then the cooled sample was tested. We did: total phenols with Ciucalteu-Folin's reagent, total flavonoids with the aluminum chloride and the total proanthocyanidins (DMACA-reagent). All measurings were done three times.
1. Hollman P, Katan M: Absorption, metabolism and health effects of dietary flavonoids in man. Biomed Pharmacother 1997, 51:305-310 2. Liu RH: Health benefits of fruit and vegetables are from additive and synergistic combinations of phytochemicals. Am J Clin Nutr 2003, 78(3 Suppl):517S-520S.
3. Results and discussion In the tea prepared with infusion method, both in apples and pears, where less of phenols (39.27 ± 0.11 and 17.22 ± 0.05 mg GAE/100 ml) compared to ones prepared with Dekokt method (56.65 ± 0 77 and 27, 69 ± 0,03 mg GAE/100 ml). A higher concentration of phenols in apples was expected, because there is more in the fresh tissue. Earlier studies have shown that apples, as grapes, have the highest numbeer of phenols of all the fruits. It was also shown that pears have significantly high number of these phytochemicals compared to the other fruit (3). In apples there are more total flavonoids (infusion 14.4 ± 0.04, Dekokt 17.2 ± 0.03 katehina/100 mg ml) than in pears (infusion 4.11 ± 0.01 and 9.3 ± 0, 01 Dekokt mg katehina/100 ml).
3. Adamus W, Greda A: Contents of polyphenols in fruit and vegetables. Elseliver Ldt. 2004, 137
The effect of sex steroids on uterine contractions and histology in acyclic rats Fedor Filipović Center for talented youth Belgrade II, Belgrade, fedorf98@gmail.com
Introduction The ovarian hormones cause cyclic changes in cell morphology and histology of the female genital tract (1). The effects of estradiol and progesterone on the contractile activity of isolated rat uterus, has already been studied (2), but the effect of these hormone s on uterine smooth muscles of acyclic comparing to adult rats are still unknown. In menopausl women, estrogen replacement therapy increases the risk of endometrial cancer (3). The aim of this study was to investigate the effect of sex hormone treatment on acyclic rats uterus.
In the control adult rats, the luminal epithelium consisting of high cylindrical cells and endometrial glands were well developed. In acyclic control rats the epithelial cell height decreased when compared with adult. The uteri of acyclic rats treated with EE were more hyperemic with higher epithelium than in the acyclic control animals. The uterine histology of P4 treated acyclic rats were similar to acyclic control group.
Materials and methods Acyclic female Wistar rats were treated with ethinyl estradiol (EE) or progesterone (P4) for 4 weeks. The third group of acyclic rats and fourth adult group served as controls. The uterine horns from the control groups were used for ex vivo testing of the contractions in organ bath. After an equilibration period, when uteri achieved stable contractions (K+ or Ca2+ ion-induced), myometrial tension was recorded after the addition of increasing concentrations of EE or P4. Part of the uterine horns from the controls and in vivo treated rats were used for histological analysis. The tissues were fixed, routinely processed, embedded in paraplast and sectioned transversely. Section were stained by the hematoxylin and eosin (H&E) and visualized under a light microscope.
Results and discussion Aplication of EE and P4 caused dose-dependent relaxation of both KCl and CaCl 2 stimulated uteri. There are no differences between relaxation effect of P4, in the presence of KCl or CaCl 2 in acyclic comparing to adult rats. On the other hand, EE has stronger relaxing effect in KCl stimulated acyclic rat uteri than in adults, while at low concentrations observed weaker effect in the uterus stimulated with CaCl 2 .
Figure 2. Transversal sections of the rats uteri. Light microscopy, H&E staining.
Conclusion Estradiol and progesterone causes dose-dependent relaxing effect on uterine smooth muscles of aciclyc rats. However, differences in estradiol mediated relaxation between adult and acyclic rats may be due to modulation of ion channel during aging. Histological analysis indicated that agerelated decline in sex hormones disrupts the structure of the uterine tissue, while subsequent estradiol trеаtment which causes hypertrophic changes may additionally contribute to the development of endometrial cancer.
References
Figure 1. Dose-response sigmoid fit curves for EE and P4induced relaxation of the isolated rat uterus
[1] Spornitz UM, Socin CD, dravid AA. Anatomical Record, (1999), 254: 116-126. [2] Aman M, Hirano K, Nishimura J, Nakano H, Kanaide H. British Journal of Pharmacology, (2005), 146: 425– 434. [3] Ziel HK. Obstet Gynecol, (1982), 60: 509–515.
IZOLATION AND CHARACTERIZATION OF DITERPENES FROM PLANT SPECIES EUPHORBIA PALUSTRIS Milica Puđa Center for talented youth Belgrade II, milicapudja@gmail.com
Supervisors: Dr Vele Tešević, associate professor of University of Belgrade Faculty of Chemistry M. Sc Gordana Krstić, teaching assistant of University of Belgrade Faculty of Chemistry
1. Introduction
C 20 –69.8 ppm) (Picture 2). Based on these data, the structure of 13–acetoksi–20–izovaleriloksi–12– deoksiforbol was determined (Picture 3).
Plant species pond spurge (Euphorbia palustris) is very rich source of milky juice-latex.1 It is known that the latex of these plants contains a large number of organic compounds, such as diterpenes, phenols, and flavonoids.2 An class of diterpenes that has been isolated from the plant genus Euphorbia is a class of tiglianes. It was found that that tiglianic type of diterpenes have cytotoxic, analgoantipyretic 3 and sedative effects.4 They also acts as irritants.5
2. Objective Picture 2: 1H NMR spectrum of fraction 25 The aim of this work is the isolation of diterpenes from plant species Euphorbia palustris, and their characterization.
3. Materials and methods Lyophilized milk of Euphorbia palustirs was extracted twice with hexane. The extract was applied to a dry-flash chromatography column, packed with silica gel. Elution was carried out by solvent system hexane/ethyl acetate, with the solvent polarity increase, i.e. percent of ethylacetate increased. Gradient elution was monitored by TLC. Total of 17 fractions from dry–flash column was eluted. Fractions 6, 7 and 8, that were equal on the basis of Rf values, were collected and subsequently separated on column chromatography. A silica gel was used as stationary phase, while solvent system hexane/ethylacetate was used as a mobile phase. Elution was isocratic, with a mixture of hexane/ethyl-acetate (V/V 8/2) and monitored by TLC also. Total of 27 fractions were eluted by the gravity column. Fraction 25th was further analyzed.
4. Results and discussion Based on the results of TLC fraction 25th was prepared for recording NMR spectra. NMR spectrum of 1H and 13C were recorded. Based on the appearance of 1H NMR spectra, it can be concluded that the compound contains two protons, which are located on the sp2-hybridized carbon (H– 1 7.61 ppm, H– 7 5.72). It can also be observed the presence of a proton which is oxygenated to carbon (H 2 0–4:45 ppm) (Picture 1). From the 13C NMR spectrum was observed: keto group (C 3 –209.1 ppm), ester carbonyl groups (isovaleroxy 170.8 ppm, acetoxy 175.2 ppm), as well as two double bonds at positions C 1 –C 2 (C 1 -161.4 ppm, C 2 –132.8 ppm), and C 6 -C 7 (C 6 -133.9 ppm, C 7 – 134.8 ppm). It also can be noticed the presence of oxygenated carbon atoms (C 4 –73.6 ppm, C 13 –63.2 ppm,
Picture 3: 13C NMR 20
Picture 4: Structure of 13– acetoxy–
spectrum of fraction 25 deoksiphorbol
5.
–isovaleryloxy–12–
Conclusion
In this paper a method of a new diterpene ester (13acetoxy-20-isovaleryloxy-12-deoxyphorbol) isolation and characterization was described. Characterization of the isolated compounds was performed by NMR spectroscopy. In further research the biological activity of the isolated compounds will be tested.
6. Literature 1. Jančić R. (2004):Botanika farmaceutika. Službeni list SCG. 2. Eke,T., et al. (2000): Arch. Ophthalmol (AMA). 18, 13–16. 3. Quing–Wen S. et al. (2008): Chem. Rev. 108, 4295 – 4327 4. Qing–Gao M. et al. (1997): J. Phytochemistry. 44, 663–666. 5. Baloch I. B. et al. (2007): Eur. J. Med. Chem. 43, 274–281.
„Slaughterhouse waste blood as a basis for making biologically valuable products“ Tamara Janković Center for talented youth Belgrade II, tamara.jankovic.97@gmail.com Hemoglobin is a tetrameric metalprotein whose main role is to transport oxygen from lung to peripheral tissues. Each hemoglobin molecule contains four iron ions, and after a conversion into specific pharmaceutical form, it can be used for prevention hypochromic anemia of human and animal. After releasing of hemoglobin from red blood cells (hemolysis), empty membranes called „ghosts" remain. They can be used as drug carriers for intravenous application. The aim of this work is to examine the possibility of isolation native hemoglobin and "ghosts" from red blood cells of slaughterhouse blood by process of gradual hemolysis.
of biologically active substances and potential possibility for being drug carrier.
Conclusion In this work we have shown that native hemoglobin and empty „ghosts“ membranes can be isolated from porcine slaughterhouse waste blood, which enables restoration of biohazard material and prevents the environment from pollution originally coming from meat industries.
Materials and methods
References
Red blood cells were isolated from porcine slaughterhouse blood by centrifugation. Hemoglobin was isolated from them by the process of gradual hemolysis, i.e. by controlled gradual lowering of the ionic strength of phosphate buffer. The process of hemolysis was followed, and quality of isolated hemoglobin, were analyzed by spectrophotometric methods. Morphology of red blood cells and "ghosts" remained after hemolysis, were analyzed by phase contrast microscopy.
[1] Radoslava Pravilović, Slavko Mojsilović, Ivana Kostić, Vesna Ilić, Diana Bugarski, Verica Đorđević, “ OPTIMIZATION OF GRADUAL HEMOLYSIS FOR ISOLATION OF HEMOGLOBIN FROM BOVINE ERYTHROCYTES”,1University of Belgrade, Faculty of Technology and Metallurgy, Department of Chemical Engineering, Belgrade, Serbia, 2University of Belgrade, Institute for Medical Research, Belgrade Serbia, 2012.
Results Red blood cells from porcine slaughterhouse waste blood had hematological indices within referent values and could be used as starting material that was processed in gradual hemolysis. Isolated hemoglobin corresponded to native oxyhemoglobin in its spectral characteristics. This hemoglobin was successfully translated into solid state by addition of maltose or ammonium sulphate, enabling its prolonged storage. "Ghosts" obtained by this process were of the same diameter as the intact red blood cells. This means that the process provided did not induce membranes disintegration, which allowed their use for encapsulation
[2] Radoslava Stojanović, Vesna Ilić, Verica Manojlović, Diana Bugarski, Marija Dević, Branko Bugarski. “Isolation of Hemoglobin from Bovine Erythrocytes by Controlled Hemolysis in the Membrane Bioreactor”, “ Department of Chemical Engineering, Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11000 Belgrade, Serbia, published online on 18th January 2012. [3] Zorka Đurić, „Isolating and obtaining preparates for treating anemia in animals of slaughterhouse blood”, Faculty of Technology and Metallurgy, Belgrade, September 2010.
Thyroid gland structure after treatment of middle-aged male rats with chaste tree oil Silvija Milosavljević Regionalni centar za talente Beograd 2
Introduction Chaste tree (Vitex agnus-castus L.; VAC) is native to the Mediterreanean and it’s applied as alternative medicine for reduction of PMS symptoms and premenopausal problems. Likewise, VAC is used for prevention and treatment of symptoms associated with andopouse, osteoporosis, benign prostate hyperplasia and prostate cancer. Significant number of physiological alternations in function of thyroid gland are associated with ageing, hypothyroidism is most common. Aim of this study was to evaluate does VAC essential oil affects the structure and function of the thyroid gland and to analyse potentional changes in thyroid gland work in animal model of andropause.
Material and methods Middle-aged male Wistar rats (16 months) were treated for three weeks with VAC essential oil (dose of 60 mg/kg body weight). After decapitation, thyroids were excised and prepared for further histo-morphometric investigations and immunohistochemical staining of enzyme thyroid peroxidase (TPO) and iodide transporter (NIS). The concetration of TSH in serum was determined by RIA kit, while total T4 and T3 were determined by ELISA asseys.
Results Thyroids of VAC treated groups have characteristic microfollicular structure. The volume of follicular epithelium and activation index were siginificantly increased (p<0.05), while the volume of the colloid was significantly decreased (p<0.05). The level of TSH, T4 and T3 in serum were significantly increased (p<0.05). Change in accumulation and localization of NIS was detected in follicular epithelium, while accumulation and localization of TPO was unchanged.
Figure 2. Immunohistochemical staining of thyroid peroxidase (TPO) and iodide transporter (NIS) in control (C) and VAC treated middle-aged male rats (VAC).
Conclusion It was demonstrated that VAC essential oil do affects structure and function of the thyroid. Administration of VAC essential oil leads to microfollicular changes in the structure of thiroid, accumulation of NIS protein and increase levels of T4, T3 and TSH in serum. Detected changes indicate increased transport of iodine in the follicular epithelium, hence increased biosynthesis of thyroid hormones. This study clearly shows that the essential oil VAC has a positive impact on the activity of the thyroid gland, and can be used in the prevention and treatment of symptoms associated with andropause.
Literature Šošić-Jurjević B. i sar. (2010). Subcutaneusly administrated Vitex agnus-castus Essential oil modulates thzroid structure and increases serum TSH and total thyroid hormone levelsin middle-aged male rats. The 14th International Thyroid Congress, September 11-16., Paris, France, 2010. Abstracts, p-0303. Ignjatović Dj. i sar (2012). Bioactivity of the essential oil from berries of Vitex agnus castus in middle aged male rats. Digest Journal of Nanomaterials and Biostructure. 7:17271734. Pantelić J. i sar (2013). Vitex agnus-castus essential oil affects thyroid C cells and bone metabolism in middle-aged male rats. Acta Veterinaria. 63:23-35.
Figure 1. Serum levels of TSH (A), T 4 (B) and T 3 (C) in control (C) and VAC treated middle-aged male rats (VAC).
Testing the efficiency of different rhamnolipid concentrations on metal removal from tailings Etir Chalabi Center for talented youth Belgrade II, Belgrade etirchalabi@gmail.com
1. Introduction Soils contaminated with heavy metals represent a serious threat for environment and human health. Particularly dangerous are tailings and waste rocks contaminated with As and other heavy metals because they show adverse effects on all organisms even if present in low concentrations. Bioremediation is efficient and economically acceptable method for dealing with this problem. Rhamnolipids are anionic glycolipid biosurfactants that have the ability to mobilize and remove metals by complexing them or by forming micelles and so increasing their solubility. Rhamnolipid features, such as low toxicity, biodegradability, the possibility of production from renewable sources as well as the possibility of the production in relatively high quantities in a short period of time, give them an advantage over synthetic surfactants as possible agents in washing technologies of metal contaminated soils [1,2].
content determination on ICP (Inductively Coupled Plasma).
4. Results and discussion Production of rhamnolipids by fermentation obtained yield of 637.8 mg/L. By using thin layer chromatography on a silica gel plate, two components in rhamnolipid mixture were observed, one with Rf value 0.174 for less mobile fraction of the mixture (di-rhamnolipids) and another 0.484 for more mobile fraction (mono-rhamnolipids). The resulting metal content in the sample of Bor tailings are generally consistent with previously published [3], while significant difference was found only in Zn content where obtained value was greater. For most metals, the highest efficiency on metal removal (Fe, Co, Cr, Zn) is obtained with control, NaOH solution without rhamnolipids. Exceptions are observed in As, Cu, Ni, Pb, Sr extraction. When it comes to different rhamnolipid concentrations, the highest leaching levels were achieved with 0.1% rhamnolipid solution.
2. Objective In this study, the possible effect of different rhamnolipid concentrations, produced by Pseudomonas aeruginosa D3 bacterial strain, on mobilization and removal of metals from tailings was examined.
3. Material and methods Rhamnolipids were produced in fermentation process by Pseudomonas aeruginosa D3 strain on PPGAS medium. It lasted 4 days on shaker at 28˚C. After separating biomass by centrifugation, rhamnolipids were extracted from fermentation liquid with a mixture of solvents, chloroform:methanol (2:1, v/v). The organic extract was dried with anhydrous sodium sulphate and evaporated on the vacuum evaporator. Mono- and di-rhamnolipid presence was confirmed with thin layer chromatography on silica gel plate, where mixture of solvents chloroform:methanol:water (65:15:12, v/v/v) was used as a mobile phase for separation. In metal leaching experiment, a sample of Bor flotation tailings was used as a substrate. Testing the efficiency of rhamnolipids on metal leaching was done with 0.05%, 0.1% and 0.15% rhamnolipid solution in NaOH (pH=11) and NaOH solution (pH=11) without rhamnolipids was used as control. Leaching experiment was done by using batch technique where extraction process lasted during the night on shaker, with solid-liquid phase ration 1:10 (w/v). The samples obtained after leaching, as well as the sample of Bor tailings, were digested with HNO 3 and normalized to 50 ml for metal
Picture 1. The content of As, Fe, Cu, Pb and Mo extracted with different rhamnolipid concentration solutions from Bor tailings
5. Conclusion Fermentation with Pseudomonas aeruginosa D3 strain on PPGAS medium yields approximately 630 mg/L of rhamnolipids. The largest metal removal is achieved with 0.1% rhamnolipid solution. Based on the results of this study, it is necessary to check the effect of NaOH without rhamnolipids as leaching solution, and to evaluate what impact solid-liquid phase ratio has on leaching efficiency.
6. References [1] M. Pacwa-Plociniczak, G.A. Plaza, Z. PiotrowskaSeget, S.S. Cameotra, Int. J. Mol. Sci. 12, (2011), 633 [2] A.A. Juwarkar, A. Nair, K.V. Dubey, S.K. Singh, S. Devotta, Chemosphere 68, (2007), 1996. [3] M.M. Antonijević, M.D. Dimitrijević, Z.O. Stevanović, S.M. Serbula, G.D. Bogdanović, J. Hazard. Mater. 158 (2008) 23
Identification of cell types generated through differentiation of NT2/D1 cells under treatment with retinoic acid Tijana Stanić Regional Centre for Talented Youth Belgrade II, Serbia, tijana.stanic.22@gmail.com
1. Introduction Cells derived from embryonic carcinoma have characteristics of stem cells, which can, under certain conditions, differentiate into different types of cells. NT2/D1 is a cell line derived from embryonic testicular teratocarcinoma, which resembles early neural epithelial progenitors. Under exposure to retinoic acid these cells differentiate into neural and glial cells. The objective of this work was to examine the morphology and identity of cells generated in the differentiation process of NT2/D1 cells.
2. Materials and methods NT2 cells were maintained under normal conditions and treated with 10 µM all-trans retinoic acid. After four weeks of differentiation, for the purpose of further analysis, multilayered cellular aggregates were trypsinised and replated. The cells were seeded on cover-slips and fixed with 4% paraformaldehyde. The cell morphology was analysed using the method of immunocytochemical staining for cytoskeletal marker alpha-tubulin, whereas neural and glial cell types were identified using immunostaining for specific markers MAP2 (for neurons) and GFAP (for glial cells). The shape and size of cells were analysed and recorded with phase – contrast and fluorescence microscopy.
3. Results and discussion At the beginning of the treatment, NT2/D1 cells appeared as dark, undifferentiated cells of granular shape, with little cytoplasm around a large nucleus. The cytoplasm of undifferentiated cells stained for anti-alphla-tubulin antibodies was detected with fluorescence microscopy. Following 4-week RA treatment, the cells formed dense multilayered culture. At this point, bright neuron-like cells with axon-like processes growing in groups over large nonneural cells, were recorded. The cells which displayed immunoreactivity for MAP2 protein were identified as neurons. Simultaneously, glial cells incubated with antiGFAP antibody were detected in a small number. Also, anti-alpha-tubulin antibody enabled the identification of the third group of cells whose identity remained unknown, as these cells did not show immunoreactivity for markers of differentiated neural cells.
Picture 1-untreated NT2/D1, alpha-tubulin and DAPI on fluorescence micrography
Picture 2 – NT2/D1 neurons after 6 weeks of RA treatment alpha-tubulin on fluorescence micrography
4. Conclusion NT2/D1 cell line represents a unique model system for studies of human neurogenesis and expression of genes involved in neural differentiation. With the method of immunocytochemistry, we have determined the morphology and identity of differentiated cells, whereas the huge cells, negative on both markers of differentiated neural cells, will be subject for further research.
5. References [1] B.D.Stefanović,V.Đorđević-Čamba,Z.Kojić,M.Bajčetić, M.Ćetković, Integrativna neurobiologija, Mikro knjiga i B&M, Beograd, 2003. [2] S.J.Pleasure, C.Page, V.M.-Y.Lee, Pure, Postmitotic, Polarized Human Neurons Derived from NTera 2 Cells Provide a System for Expressing Exogenous Proteins in Terminally Differentiated Neurons, The Journal of Neuroscience, 1992. [3] G.Podrygajlo, M.A.Tegenge, A.Gierse, F.PaquetDurand, S.Tan, G.Bicker, M.Stern, Cellular phenotypes of human model neurons (NT2) after differentiation in aggregate culture, Cell Tissue Res 336-439-452, 2009. [4] Peter W. Andrews, Department of Biomedical Science, Western Bank, Unievrsity of Sheffield, From teratocarcinomas to embryonic stem cells, Phil. Trans. R. Soc. Lond. B, 2002.
Effect of strawberry extract on hydrogen peroxide induced DNA damages AnjaDekanski Regional Center for Talented YouthBelgrade II, UstaniÄ?ka 64, Belgrade, Serbia
Introduction Strawberries (Fragariaananassa, Dutch) are common and important fruit due to their high content of essential nutrient and beneficial phytochemicals which seem to have relevant biological activity on human health. Recent research shows that strawberry extracts identify as efficient antioxidative agents against increased level of oxidative stress [1,2]. In order to understand the mechanism of the effects, but also to determine their effects on human health, it is necessary to investigate the impact of the strawberry in appropriate systems. It is known that DNA is highly sensible when it comes to oxidative stress in comparing to other molecules and numerous references show that DNA damages induced by oxidative stress can influence the development of chronicle diseases and cancer [3].Hydrogen peroxide is an agent that causes damages, one-chained and two-chained breaks on DNA molecules.The objective of the work is to investigate the effect of a strawberry extract in attenuation of DNA damages induced by hydrogen peroxide in human lymphocytes, as well as observing the existence of dose dependency in order to determine the optimal concentration.
Fig 1. Effect of different concentrations of strawberry extract on the level of DNA damage Although, all investigated concentrations of strawberry extract decreased the level of DNA damages, only the concentration of 0.1 mg/mL showed the statistically relevant effect (Fig 2). The lack of dose dependant effect of the extract implies that there is a concentration with the best effect. According to that, the concentration of 0.1 mg/mL represents the optimal concentration in described experimental conditions.
Experimental The metanolic, polyphenolic-rich strawberry extract was obtained from Marche Polytechnic University, Ancona, Italy. The level of DNA damages in treated cells is determined by the electrophoresis of single cells, known as the Comet test method [4], which is widely used in similar research. Firstly, the strawberry extract was tested on its genotoxicity potential, or in other words its ability to cause damages on the DNA molecule. Peripheral blood leukocytes from six young and healthy volunteers were treated in vitro with different concentrations (from lowest to highest:0.025, 0.05, 0.1, 0.125, 0.15, 0.2 mg/mL) for 30 minutes before measuring the level of DNA damages in treated cells. After that, in order to investigate the antigenotoxic effect of the strawberry extract, the same cell samples were treated were treated in vitro with hydrogen peroxide for 20 minutes before the in vitro treatment with the strawberry extract (concentrations of 0.025, 0.05, 0.1, 0.125, 0.15, 0.2 mg/mL)and the incubation for 30 minutes. The control group were the cells treated only with hydrogen peroxide.
Fig 2. Effect of different concentrations of strawberry extract (SE) decreased the level of DNA damages by H 2 O 2
Conclusions These obtained results confirm that the strawberry extract does have genoprotective and antioxidative properties, which makes it recommendable for use and suggests further research on the mechanism of its effects.
Results
References
The results after investigating the potential genotoxcity show that the strawberry extract does not increase the level of DNA damages in described conditions (Fig. 1).
[1] Giampieri F, et al.,Nat ProdRes. 2013;27(4-5):448-55. [2] Basu A, et al.,Crit Rev Food SciNutr. 2014;54(6):790806 [3] Khansari N, et al.,Recent Pat Inflamm Allergy Drug Discov. 2009;3(1):73-80. [4] Singh NP, et al.,Exp Cell Res. 1988;175(1):184-91
The strawberry extract significantly attenuated the induced DNA damages in comparison with the control group, according to the obtained results, which implies that it exerts genoprotective properties.
Effects of disinfectants Peral S® and Sekusept® Pulver on methicillin - resistant staphylococci isolated from animals and humans Introduction The appearance of methicillin-resistant staphylococci (MRS) presents one of the biggest problems in human and veterinary medicine, because they show resistance to all beta-lactamic antibiotics and most other antibiotics that have clinical appliance. Because of effective antibiotics’ limited choice, MRS strains cause fatal infections on humans and animals. Also, because of dramatic deterioration of epidemiological MRS situation, World Health Organization (WHO) and World Health Organization for Animals (OIE) recommend decrease and severe control of antibiotic use and, at the same time, increase of disinfection measures in hospitals and on farms. How the prevalence of MRS resistance on different disinfectants is increasing, the question is how disinfectants affect methicillin – resistant staphylococci. The goal of this research is to determine if MRS strains can be exterminated by two commercial products that are widely used in Serbia for hands’ and instruments’ disinfection.
Materials and methods MRS strains from ear, eye, skin and nose smears originated from dogs, cats and humans were used in this research. Staphylococci have been identified by API ID 32 test (bioMerieux). Control group were strains MRSA ATCC 43300, ATCC 33591 and S.aureus ATCC 25923. The evidence that isolated staphylococci belongs to MRS was the presence of mecA gene using PCR. Antibacterial activity of Peral S® (Midra Eko DOO, Serbia) (0.2% and 0.5% concentrations) and Sekusept® Pulver (Ecolab, Germany) (2% concentration) was tested. Peral S ® is peracetic acid, while Sekusept ® Pulver has combined chemical composition. Qualitative suspension method and BS EN 1276:1997, method for quantitative analysis of disinfectants' bactecidial effects, were used in research. In suspensional method, MRS strains were inoculated in disinfectants' solutions (final number 9x106 per mL) and efficiency was done on 5, 10, 15, 20, 30 and 60 minutes. In BS EN 1276:1997 the final number of bacteria was 6x107 per mL and efficiency was done on 2, 5, 10, 15, 20 and 30 minutes.
Results Results show that Peral S ® concentration 0.2% and Sekusept ® Pulver concentration 2% in suspensional method kill all MRS strains. However, BS EN 1276:1997 method shows that Peral S ® concentration 0.2% wasn't effective in 2 minutes, because 6 of 15 strains survived disinfectant effect and even two survived the effect for 5 minutes. In BS EN 1276:1997 method Peral S ® concentracion 0.5% killed all strains in 2 minutes, but Sekusept ® Pulver concentration 2% wasn't effective in 2 minutes, because 7 of 15 strains survived, but this disinfectant was effective in exposition time of 5 minutes.
Conclusion BS EN 1276:1997 was more precise in the evaluation of disnifectants' efficiency. Peral S ® concentration 0.5% in 2 minutes kills all present MRS strains. If lower Peral S ® concentrations were used the disinfection time would last at least 10 minutes. Sekusept ® Pulver in reccomended concentration of 2% is effective in minimum of 5 minutes.
Determination of the pandemic potential of the H5N1 virus with bioinformatic methods Marko Tumbas Center for talented youth Belgrade II, Belgrade, tumbasm@gmail.com from 1996 as well as the characteristic sequences from 2006 that shows the evolution of HA1 and his affinity for the human receptor (Figure 2).
1. Introduction The H5N1 virus was first isolated in 1996 in Hong Kong during outbreaks among poultry. Since then it has been its geographic expansion and adaptation to greater efficiency of transmission to humans. The most important protein of the H5N1 virus is hemagglutinin[1]. One of its two subunits, the HA1, has a role in the cell receptors binding. HA1 has spectral characteristics that are reflected in the efficiency of transmission. Frequency F(0.076) corresponds to the animal and F(0.236) with the human receptor. Analysis of proteins of the influenza virus H5N1 have shown that there may be mutations in the HA1 part of protein that would affect its pandemic potential.
2. Materials and methods In this research we used hemagglutinin protein sequences isolated since 1996. Sequences were downloaded from the website Influenza Virus Resource[2]. The HA1 subunits were segregated from the sequences. ISM tree program[3] is used to determine the evolutionary tree. Sequence similarity is based on the ratio between frequency 0.256 and 0.076. Priority was given to the ratio of HA1 sequences that is greater than F(0.236)/F(0.076)>1. For the further analysis of the sequences is used χ2 test. Individual sequences are graphically displayed using IS method. Then these typical examples were subjected to the multiple sequence alignments [4]. Monitoring and prediction of mutations that would lead to an increase in the ratio 0.236/0.076 is conducted by AK scanner.
3. Results and discussion Evolutionary tree was used to select the important sequences and locate infection hot spots. On the evolutionary tree there are three groups of sequences with the ratio F(0236)/F(0076)>1 They are originally from Germany, Egypt and Nigeria (Figure 1). Zemlja porekla Broj sekvenci >1 Egipat 101 Nemacka 58 Nigerija 56 ostali 238
Figuree 1 – The sequences of the amplitude ratio F (0236) / F (0076)> 1 The obtained data indicate a significant change in the number of sequences with a ratio F(0236)/F(0076)>1 over the years. The results are consistent with data from the World Health Organization on the number of recorded cases. Analyzed sequences belong to the original sequence
Figure 2 – HA1 protein sequences with the IS method A – 1996 Guandong goose, B- 2006 Nigeria chicken 24 C – 2006 Germany duck, D – 2006 Nigeria Chicken 38
Figure 3 – Part of the aligned sequences 241-260 Multiple alignment of sequences is showing a mutations which have a variety of effects on the protein (Figure 3). Predictions that would lead to an extreme increase of the 0.236/0.076 ratio are conducted on the last available sequences. The spectra of the potentially most problematic mutations are shown in Figure 4.
Figure 4 – Predicting the effects of mutations A – D54A, B – F290I, C – I284R
4. Conclusion The results show us that the greatest pandemic potential until now have sequences from Egypt, Nigeria and Germany. The largest number of sequences with a value of F(0.236)/F(0076)>1 was in 2006. That corresponds to the peak of infection. Mutations at positions 54, 284 and 290 of HA1 protein may lead to an increase in the potential and trigger a new infection.
5. References [1] V. Veljkovic, N. Veljkovic, C.P. Muller, S. Muller, S. Glisic, V. Perovic, H. Kohler. BMC Struct Biol. 9, (2009), [2] Y. Bao, P. Bolotov, D. Dernovoy, B. Kiryutin, L. Zaslavsky, T. Tatusova, J Virol. 82, (2008), 596-601. [3] V.R. Perovic, C.P. Muller, H.L. Niman, N. Veljkovic, U. Dietrich, D.D. Tosic, S. PLoS One. 8, (2013), e61572. [4] F. Sievers, A. Wilm, D. Dineen, T.J. Gibson, K. Karplus, W. Li, R. Lopez, H. McWilliam, M. Remmert ET AL. Mol Syst Biol. 7 (2011), 539.
Genomic stress influence on wing size and shape in Drosophila subobscura Dijana CvijetiÄ&#x2021; Regional Center for Talented Youth Belgrade II, Serbia, dijanachl@gmail.com
1.
Introduction
Inbreeding, mating between close relatives, is a genomic stress that may disrupt the stability of the genome [1]. This phenomenon occurs in nature, especially in situations of habitat fragmentation caused by anthropogenic influence, global climate changes and rapidly growing pollution. In those cases, population could be isolated for a certain period, which would lead to mating closely genetically related individuals [1]. Inbreeding results in homozygosity, and has both positive and negative effects on whole range of traits, including morphological traits and fitness components [2].
clear sexual dimorphism in this species (Picture 2). There is significant interaction between sex and groups (Table 1). Effect group sex group x sex
df 3 1 3
MS 23606 492693 4089
Error
481
626
F 37.7 *** 787.2 *** 6.5 ***
Table 1. Two-way ANOVA on wing size (CS) of individuals from four groups and both sex
The aim of this study was to evaluate influence of experimentally increased homozygosity, as genomic stress, after 14 generations of full-sib inbreeding treatment in laboratory conditions on Drosophila wings morphological traits.
2.
Materials and methods
In this experiment, highly inbred lines of D. subobscura, originating from two ecologically and topologically distinct habitats (Botanical Garden in Belgrade and Sicevo gorge) were used, knowing that they possess a certain degree of genetic differences due to their different evolutionary histories. Beside homozygotes from inbred lines, heterozygotes from direct and reciprocal crosses between these populations were used. For analysis of phenotypic variability of the wings males and females were separated. The right wing of each fly was fixed and the digital photograph was taken. Images were landmarked with 13 landmarks (Picture 1). Wing size was examined using centroid size (CS) and shape was examined using weight matrix (wm). Differences in CS were tested with ANOVA, and the ones in wm with MANOVA.
Picture 2. Mean values of centroid size for all experimental groups and both sexes MANOVA showed no difference in wing shape between experimental groups, as a result of different genes and genetic pathways involved in development of these wing morphological characteristic [3], and which is consistent with results of previous studies.
4.
Conclusion
Understanding nature of phenotypic variation is important aspect of evolutionary biology. One of the reasons why homozygous individuals have smaller wings may lie in fact that more recessive genes are expressed in phenotype than expected, which can lead to lower performances in individuals as well as in populations. Another explanation is heterozygote superiority, theory which states that higher level of heterozygosity increases fitness of an individual, and since the wing size is closely related to a fitness of an individual, obtained results are in concordance with this theory.
5. Picture 1. Right wing of D. subobscura with 13 landmarks
3.
Results and discussion
The results for wing size showed significant difference between homozygote and heterozygote groups (Table 1). Heterozygous individuals have larger wings than homozygous (Picture 2). Also, between sexes is significant difference: males have smaller wings than females, due to
References
[1] L. F. Keller, D. M. Waller, 2002: Inbreeding effects in wild populations. Trends in Ecology & Evolution, 17: 231. [2] M. Lynch 1997: Inbreeding depression and outbreeding depression. In: Genetic effects of straying of non-native fish hatchery fish into natural populations. W. S. Grant (editor). U.S. Dep. Commer., NOAA Tech Memo. [3] V. P Carreira, I. M Soto, J. Mensch, J. J Fanara, 2011: Genetic basis of wing morphogenesis in Drosophila: sexual dimorphism and non-allometric effects of shape variation. BMC Developmental Biology, 11: 32.
MATHEMATICS
Games around us Knežević Luka
1.Introduction
Center for talented youth Belgrade II, Belgrade, knezevicluka08@gmail.com terms, firm 2 will accept (Y), and profit of firm 1 will be even lower. You can see that in picture 2.
We are surrounded with different competitions and games, but we have not properly introduced in it. Every single decision and move can be consider by mathematics. Seemingly, logical solutions are not always the best, like i thought. That is the reason why I use simple example from everyday life.
2.Method Picture 3-Threats I analise new and existing examples from “Game theory“, which we can apply it in everyday life.
3.Results I found new conclusions about sequence games, and also winner strategies.
If some new firm considers entering the market, the old one will lose their clients. They try to stop that with threats of price war (PW). That is not credible threat because profit of old firm is 0 in cause of price war, and in cause of not price war (NPW) they spare the clients. You can see that in picture 3. We come to this conclusion using Nash equilibrium, Prisoner's dilemma, backward induction and credible threats.
4.Conclusion We saw that mathematic is all around us, and that we should verify every strategy. That is only way to find the decision. I try to learn more about “Game Theory”, and find more and more new examples and purpose in everyday life. Picture 1-Selections rate In this picture you can see possible profit of firm 1 and firm 2 after they choose high (H) or low (L) price of article. You can also see that chosen profit is not the biggest, but it is safest, because firm 1 and firm 2 do not cooperate. They always choose strategy with larger profit.
5.
References
1.http://gatton.uky.edu/faculty/sandford/401_f12/sequential .pdf 2. http://bk.docsity.com/sr-video/13__Sekvencijalne_igre 3.http://www.ef.uns.ac.rs/Download/menadzment_rizikom_ master/2010-01-11_teorija_igara.pdf 4.„Теорија игара: примена“,Стојановић Божо
Picture 2-Selections of adverts If firm 1 accept (Y) terms for commercial, their profit would be less than before, but if they do not accept (N) that
елементи
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Kirkman’s schoolgirl problem Nikolina Marković Center for talented youth Belgrade II, Belgrade, nikolinam98@gmail.com so that h−1 must be divisible by k. if the quotient is marked by p, i.e. p =
1. Introduction Kirkman’s problem falls within the area of so-called “recreational mathematics” and it reads as follows: 15 schoolgirls walk to the school every day in five groups of three girls, it is necessary to make a weekly schedule of groups so that each pair of schoolgirls is in the same group only once. In order to solve this and similar, practical problems, it is required the knowledge of the combinatorics methods of the finite groups. Solution of the problem leads to the so-called Steiner triple system, named after the works of Jacob Steiner. The aim of the present study is to find the solution for the Kirkman’s problem and its connection with the block design and Steiner triple system.
, after a short transformations we get: v=g∙k
(1)
On the fixed and rotating disc, shown in Figure 1, where the triangles and dots are marked, we have the solution for v=15. Indicated triangles are actually the required triplets and therefore, they can’t be compatible. The initial position where the numbers and dots on both discs overlap, gives the arrangement of triplets for the first day. The arrangement for the next six days, we will get by rotating the upper disc for the two units in any direction. This means that point 1 at the rotating disc should coincide respectively with the numbers 3, 5, 7, 9, 11, 13 on the fixed disc (or in reverse order, whatever).
2. Work methods The problem can be solved by research in many different ways, but only those types of solutions that are of practical and theoretical interest are those that are based on the methodology of mathematics. Firstly, we set the algebraic conditions for the solution of the problem. The second approach is to properly generalize the problem and understand it through solving the simple examples. Some of the solutions are presented by using the fixed and rotating disc. Then, subject to certain rules, we edit a group of 15 elements and form triplets. We define a block design, Steiner triple system and parameters of Kirkman’s triple system.
Figure 1-Solution for v=15 The most important application of the Kirkman’s problem is in the development of the basic theory of block designs, with which I was occupied with in the final part of my paper.
4. Conclusion 3. Research results It doesn’t need much to realize that finding the solution is not so trivial. Since the number of girls is positive integer v, and they, according to the conditions of the task, have to walk every day in g rows, where each of them consists of k girls, it is obvious that v=g∙k
(2)
From these two equations we get: g =h −
5. Literature
(1)
Each girls walks with k − 1 different companion every h days, therefore she walks with each of hers companions v − 1. Algebraic expression of this condition is: v−1=h
Kirkman’s schoolgirl problem does not require the knowledge of many abstract mathematical methods. For its solution, it is necessary to know the basic combinatorics methods of finite groups, and its implementation has generated the elementary theory of block design.
(3)
[1.] D. Cvetković, S. Simić, Kombinatorika i grafovi, Belgrade, 2006 [2.] G. Berman, K. D. Fryer, Introduction to Combinatorics, New York-London 1972 [3.] M. Petković, Zanimljivi problemi velikih matematičara, Belgrade, 2008 [4.] The Astronomic Journal, Cyclic solutions of the school-girl puzzle, vol. VI, 1859-1861.
Competitive strategy- Game theory Uroš Jakovljević Regional centre for talented youth II, Serbiа, urosh.belgrade@gmail.com
1
Introduction
In everyday life we often have to decide between two things. We are players of one great game, and we aren’t aware of it. We wanted to understand our life better, and events, and we wanted to know what will happen if we buy pizza, and what when we buy roll in bakery, we wrote this research. This section of math shows reality, real oppotunities, аnd real profits.
2
Мethods Picture 2 – Basic matrix of the game Here we have situations depending of the prices which coul players choose. These are real profits of this game. 6.0/ 6.0 means that left price is for bakery Rim, and right for bakery Suzana. Profits are in thousands of dinar valute. This is also applied for everything in matrix. But precisely that player's strategy is often deadly for their together profit.
Picture 1- bakery We are using many examples and illustrations in our academic work so we could explain basics of this theory. In that examples we are observers, we follow their rational decisions, and eventually we criticize them. We follow competitive situations in form of the game. First we will start with two bakeries. That would be simultaneous game (where both players make moves at the same time) and we will see their actions in matrix so we could try to find optimal strategy.
3
Results
Rational player always choose domminant strategy. We conclude that our opponent will play rational too, so he will use dominant strategy. Research showed to us that there is situation where players usually don’t want to change their strategies, and that situation is named Nash equilibrium. Nash equilibrium is concept of solutions of the game, where we know that every player knows strategy of his opponent , and neither of them could profit by changing only his strategy. That solution of the game is Nash equilibrium.
Prisoner's dillema means that in the game exsits situation where both player get bigger profit, but individually looking, neither of them don't want to play that move. In our work we answered why is this most common situation in life.
4
Conclusion
This research that is generally about competitive strategy of two bakeries, we learned why there is need to consider strategies of other players when we want to have our own decision, because we aren't in vacuum, and our actions will trigger reactions of other players. If we act strategic and smart we can predict those reactions, and that can be very important when we aren't sure what decision is the best. In this research we learned about simultaneous games, about the matrix of the game. We know how to find dominant strategy, and while we were analyzing the game we found Nash equilibrium and Prisoner's dillema. We saw that there is reason for cooperation, and that with cooperating we can maximize our profits.
References 1. ,,Победа или пораз – Стратегије и Теорије игара'' - Никола Милић и Лука Станојевић 2. https://www.youtube.com/watch?v=x8gOi7D6QeQ
Tessellation Mina Šekularac Regional Center for Talented Youth BelgradeII, minasekularac@hotmail.com
1. Introduction This research paper deals with tessellations that have been used since ancient times. The word tessellation means covering or tiling of different types of surface using geometric shapes. The patterns are repeating with no overlaps and no gaps. Such complex shapes create various patterns, forms and colours, as seen in tiled surface, mosaics and stained glass.
1-uniform tessellations of the Euclidean plane Theorem 1: There are 11 1-uniform tessallations of the Euclidean plane: − 3 regular monohedral tessellations, − 6 regular dihedral tessellation and − 2 regular tessellations consisting of three regular polygons.
2. Working method This project included the following research methods: − Data gathering and analysis in this field, − Analysis of previous research activities in this field, data processing and systematization, − Conclusion method using the previos facts aboot general knowledge The results about the research on tessellations and their everyday application will be presented in the form of summarization and interpreation of the previous facts, knowledge and the latest conclusions made by this research.
3. Research results Tessellations from ancient times to the present days th
Not until the 17 century was the term tessellation defined in mathematics, although ever since the ancient times men have dealt with geometric figures and their combinations in order to have various surfaces covered. Nowadays, the principle of tessellation is applied in numerous fields – textile industry, creating textile patterns, construction, design elements of floor and wall covering, art, science, optics and crystalgraphics. Also, tessellations are included in various board games, children’s puzzles, complex computer games, computer graphics and design.
Figure 1. Graphic display of all regular 1-uniform tessellations
4. Conclusion Researches on tessellations have existed for centuries. Apart from both theoretical and practical importance in the field of mathematics, tessellations are present in nature, art, architecture and construction as well as in digital art and modern graphics. Geometry is one of the main fields of mathematics; thus, the research activites dealing with geometry will never stop, just as there are never-ending combinations of various geometric figures and types of using geometric figures in order to cover different surfaces that are repeating without overlapping and gaps. Tessellations are limitless, therefore – the possibilities of geometry and mathematics are vast and without boundaries.
Classification of Tessellations The Euclidean plance tessellation are divided into: − Monohedral tessellations – all tiles are congruent, − Dihedral tessellations – all tiles are congruent to one of two tile shapes, − 1-uniform tessellations – for any of two vertices there is a transformation from S(τ) that reflects one vertix on another (S(τ) is a symmetry froup of that tessellation), − Regulat tessellations – all tiles are regular, equal polygons.
Literature [1.]
Z. Lučić: Euklidska i hiperbolička Univеrzitеt u Bеоgrаdu, Bеоgrаd, 1997.
geometrija,
[2.]
Tangenta - časopis za matematiku i računarstvo, 21. br, Beograd, 2000.
[3.]
http://mathworld.wolfram.com/Tessellation.html
[4.]
http://jwilson.coe.uga.edu/EMT668/EMAT6680.2003.f all/Thomas/Tessellation%20project/History.htm
Bee colony optimization for Hamiltonian p-Median problem Dejan Kovač, supervisor mr Nataša Kovač Centre for talented youth II, Belgrade, kovac.dejan.montenegro@gmail.com
This research presents a new algorithm based on metaheuristic algorithm with bee colony optimization, whose aim is the formation of suboptimal solutions for Hamiltonian p-median problem. The proposed algorithm has a goal to allocate the set of n vertices given in Euclidian plane within k disjoint circuits in shortest processor time. The subsets of vertices are than used in formation of Hamiltonian cycles, in such way that the cost function, which in this research represents the total length of all Hamiltonian cycles, is minimized. After the implementation of basic bee colony optimization algorithm, the two improvement techniques are applied on the formed complete solutions obtained by the basic algorithm.
Table 1. columns show the values of the cost function after the run of the basic algorithm, algorithm with Improvement I, and algorithm with both Improvement I and Improvement II, as well as the processor time needed for obtaining the solutions. The basic algorithm was tested, and the values of the cost function together with the processor time needed were given. After that, the basic algorithm is enriched with Improvement I, which eliminates the self-intersection of Hamiltonian cycles, which leads to improvement in quality of complete solutions but increases the CPU time insignificantly. In the end, the same set of test examples is tested on an algorithm which represents an integration of the basic algorithm together with the two improvements, where, besides the elimination of the self-intersections, the Improvement II is used to eliminate the intersection between two or more cycles.
2. Methods
4. Conclusion
During the research, a literature in which are described a mathematical formulation of Hamiltonian p-median problem and a detailed description of bee colony optimization algorithm was used. Algorithm and the formulation of the problem were coded in Wolfram Mathematica v8.0 programming language. During the literature overview, it couldn’t be established that the other authors approached this problem in a proposed way, so this research represents a contribution in this field of research.
Based on the preliminary solutions, it can be concluded that the algorithm gives good results in generating and improving solutions for Hamiltonian p-median problem. Based on the experimental results, the proposed implementation of the algorithm can be successfully used in obtaining good-quality complete suboptimal solutions of Hamiltonian p-median problem. The processor time values are very low, and the quality of generated solutions allow them to be used as starting results for exact methods for solving Hamiltonian p-median problem. Also, it is showed that it is efficient to develop techniques for improving complete solutions generated by bee colony optimization, where it is necessary to develop efficient techniques who will improve the solutions in minimal CPU time. In these test examples, the suggested techniques gave an improvement of suboptimal solutions with insignificant increase in CPU time.
1. Introduction
3. Results Algorithm was tested on an example proposed in scientific literature, and later on the artificially generated test examples. All the tests are performed on a computer with the processor Pentium 4 3.00-GHz CPU with 512 MB RAM under Microsoft Windows XP Professional Version 2002 Service Pack 2 operating system. In the first test example, which was proposed by the authors in [4], the algorithm was capable of obtaining optimum for 0.01 seconds, which was an encouraging sign that the proposed algorithm was well developed. The Table 1. shows some of the results for the tests with n vertices. n 33 34 35 36 37 38 39 40
BCO 168.529 155.284 154.383 168.479 145.151 139.644 162.545 182.150
BCO with 5 bees, k=3 minT Impr.I minT Impr.I+II 0.076 159.125 0.078 156.620 0.076 152.956 0.078 150.737 0.092 151.626 0.093 147.943 0.093 154.989 0.093 152.097 0.078 139.119 0.078 134.761 0.078 137.426 0.078 134.848 0.092 156.019 0.093 158.325 0.107 179.970 0.109 179.263 Table 1. Numerical results
minT 0.156 0.156 0.171 0.187 0.187 0.187 0.203 0.218
References [1] H. Glaab and A.Pott (2000) “The Hamiltonian pMedian Problem,” The Electronic Journal of Combinatorics, 7, 1-25. [2] M. Zohrehbandian (2007) “A New Formulation of the Hamiltonian p-Median Problem,” Applied Mathematical Sciences, 8, 355-361 [3] P. Lučić and D. Teodorović (2001) “Bee system: modeling combinatorial optimization transportation engineering problems by swarm intelligence”, Preprints of the TRISTAN IV Triennial Symposium on Transportation Analysis, Sao Miguel, Azores Islands, pp. 441-445 [4] M. Zohrehbandian, S. Hamidnia namini (2010) “Ant colony optimization techniques for the Hamiltonian pmedian Problem”, Mathematical sciences, Vol. 4, No. 4 383-390
Graph theory Miloš Kaličanin
1. Introduction
Regional talent center Belgrade II, Belgrade,miloskali@hotmail.com the road map. After touring the last city we would return back to Belgrade. Determine the order of the city tours and returning to the hotel to obtain the shortest path.
The purpose of research is introduction to the graphs using definitions and theorems, as well as setting of the problem and coming up with a solution in different ways. In this research I will adduce general characteristics and some types of graphs, such as Euler's and Hamilton's, which is a theoretical introduction to the graphs. The practical application of this knowledge will be reflected in the analysis and resolution of problems in various ways. The application of graph theory is a broad and mostly represented in the programming, but can be applied in everyday life, for example, when creating schedules, while driving a car, walking, etc.
2. Working methods It's composed out of the following paragraphs: -
analysis of data collected from the literature
-
analysis of previous research in this area
-
use of theoretical knowledge in solving problems
-
implementation of the survey
To check the results, I used a graph with assigned weightiness that I made with the help of graph theory. The results were:
Chart No.1 - Presentation of survey results The optimal solution of the research was found by 23% of students. The solution which path was up to 10% longer than the optimal, was found by 29% of students. The solution which path was more than 10% longer than the optimal, was found by 48% of students.
4. Conclusion With the analysis of the survey results, we see that a large number of students found a solution that does not meet the needs of cost and time saving. This means that introducing and applying the theory of graphs significantly relieves the everyday problems, and thereby the save of time and money would be much higher. Picture No.1 - Creating a survey
5. Literature 3. The results of research [1.] www. wikipedia.org/sr-ec/Теорија_графова The research results represent an analysis of a survey that was conducted. The task was: We observe the plan of excursion: departure from Belgrade, entry into Italy late in the evening, going to hotels and accommodation during the night. It is necessary to visit 6 places / cities (San Marino, Florence, Siena, Venice, Verona and Pisa), except that accommodation in hotels is possible in just 3 places (Rimini, Montekatini Terme and Lido di Jesolo).It is possible to visit only one city per day, and at night, it is obligated to return to hotels. The first picture shows cities and their marks on the map, and the second picture shows
[2.] Vladimir Baltić, "Graph theory for students of University of Organizational Science who listen to Discret mathematical structures", Belgrade, 2008
[3.] www.viser.edu.rs/download.php?id=7040 [4.] http://www.selimbegovic.com/Dokumenti/Metricki %20problemi%20u%20teoriji%20grafova.pdf [5.] Dragan Stevanović, Marko Milošević, Vladimir Baltić, " Discreet Mathematics, Basics of Combinatorics and Graph theory, Workbook", Belgrade, 2004
Chaos, indeed Никола Милић Supervisor: Виолета Комненовић Center for talented youth Belgrade II, Serbia, necromancer0010@gmail.com
1
Introduction
Chaos theory is one of the newest and most interesting fields of abstract science and complex mathematics. Chaos theory is the very essence of order, and our goal is that, in this scientific research, we explain to the readers: what is chaos theory all about, how is it discovered, and what are everyday manifestations of chaos which we can observe What prompted us to study this topic is meteorology. We asked ourselves: "How is it that in the modern era, with a very precise measuring instruments and mathematical models we still can’t predict the weather in the long run?". The answer to this, and many other issues we gradually discovered during our research.
2
Materials and methods
With well observed background of this interesting science, chaos theory, in which we explained its initial ideas (concepts such as determinism, initial conditions, the unpredictability of the results, as well as the famous "butterfly effect"), we tried to implement the theory through experiments. These experiments demonstrate that chaos manifests itself in everyday life and it is through these calculations and computer simulations that we see this world is a complex system in which there are a myriad of variables, and in which we try to at least as much - create some order.
3
Results and discussion
With this experiment we want to show the Bunimovich stadium – dynamic system that shows a sudden change in the path of the body prior to small errors in the initial trajectories. We will explain the calculation of the path of the ball in the example of the classic pool table, and then we’ll pass it on to the “modified” version - Bunimovich stadium. Classic rectangular pool table ( Fig. 1 ). For easy explanation the holes are removed.. Also magine that there is no friction on the floor, and when striking the wall ,the ball loses no energy and keeps moving until the end of observation .Calculating the path is very simple , the angle of incidence is equal to the repulsive angle, for each ball collision with the wall. It’s the easiest way to predict the trajectory of the ball.
Fig. 1
Fig. 2
Bunimovich stadium( Fig. 2). The top and bottom sides are parallel, and instead of the other two sides , there are two semi - circles. Even in this model, it is easy to calculate the trajectory. Again, we have the fact that the angle of incidence is equal to the repulsive angle, except that the section of the stadium where there are semi - circles , it is determined by looking at the tangent point. Now we are going to (on two examples with their own initial conditions that are very similar) show the development of drastic
change in the direction of the path in Benumovich stadium. Fig. 3
Fig. 4
For the initial direction 1 ( Fig. 3 ) development of the situation goes from the point П at А1,Б1,В1.... flowing in the manner shown in the fig . Note the positions of these points where there is a collision with the edge of the table. For the initial direction 2 ( Fig. 4 ) the same initial position П , the development of the situation is quite different. We note that due to the very small changes in initial angle of direction , a new point of refusing А2, Б2, В2.... are very moved and the system quickly turns into something of completely different looks. Points of index 2 are with each subsequent collision further than all the points the index 1 , all because of a small change in the initial angle. In this example , we wanted to show that with even a very small change in initial conditions we can quickly see the development of the situation in a completely different way . The focus of this experiment is on the speed of development of extreme sensitivity on the initial conditions.
4
Conclusion
Such a simple system may exhibit chaos, as is the case with the present. A small change in the angle (you wouldn’t think will change the end result so much) just caused a tremendous change very quickly. Bunimovich stadium is just one of a series of experiments we present in this paper, that are used to show the "presence of chaos." Our goal is to prove that not everything in life is so certain and predictable as many think.
PHYSICS
Geophysical Surveys at Archaeological site near Krušik stadium in Valjevo Borko Rajović Military Grammar School, Belgrade, borko.rajovic@gmail.com
Introduction Geophysical survey in archeology are increasingly implement. Each geophysical method provides information about a particular physical feature of subsurface. By integrating these data, provide complete information to determine the possibility of archaeological remains in the ground. Archaeological site on which geophysical survey is conduct, represents the remains of a medieval monastery Gradac and is located in the town of Valjevo. The task of research is to determine the differences in electrical resistance of subsurface and the gradient of the Earth's magnetic field. The aim of the research is to identify the areas whit possible existence of archaeological remains.
Figure 1: Resitivity anomaly map at 2m depth interval
Methods Figure2: Resistivity profile P1 Based on previous archaeological research, area 20x20m is determined near the entrance to Krušikov stadium, and area along the wall of the stadium, for geophysical electrometry and magnetometry survey. For the magnetometry survey, we used Gem Systems Overhauser GSM magnetometer with two probes (gradiometer). Magnetometry data acquisition was carried out in area 20x20. Magnetic profiling was oriented approximately in a north-south direction, and opposite. Distance between profiles was 1m, sampling was 0,5m (Starčević i Đorđević 1999.). For electrometry suvery Wenner array was applied with Lipman 4points instrument. Electrometry data acquisition was carried out in same area within parallel profiles applying mapping and profiling technic. Distance between profiles was 2m, spacing between geoelectric measuring points was 2m, for geoelectrical mapping. Geoelectrical profiling was carried out at three profiles, with Wenner array, at 4 depth levels, 0,5m, 1m, 1,5m and 2m (Vukadinović 2011). Cabinet work included the processing of the obtained data, after which anomaly map of resistivity and the vertical gradient of the Earth's magnetic field at the target area were created, and profiles of the resistivity. Data processing was performed using the program Surfer 11 and Res2D.
Figure 3: Resistivity profile P2 Anomalies that indicate the provision of the walls were determined, and the third profile located near a perimeter wall of the stadium, where on the other side remains of the church are found. Results of the magnetometry measurements are partially correlated with electrometrical data, however, in order to eliminate noise in the signal, they need to be further filtered and processed.
Conclusion Obtained data showed certain anomalies. Anomalies identified on the resistivity anomaly map and the two resistivity profiles match, which indicates that there are archaeological remains. However, this resultts do not coincide completely with anomalies obtained with magnetometry survey. In addition, anomalies in the third profile indicate the existence of the remains of the church outside the currently known site area.
Results On the resistivitay anomaly map in-depth level of two meters (Fig. 1) two positive anomalies were observed. In order to determine the cause of the observed anomalies we conducted two resistivity profiles, across these anomalies. Profiling results confirmed the existence of archaeological objects in zones of maximum value resistivity anomaly map (Fig. 2 and 3). Based on previous archaeological findings, it is assumed that it is a stone tombs. However, in order to determine the exact causes of these anomalies, need further archaeological research
References 1.
Starčevič M. i Đorđević A. (1998) Osnovi geofizike II Gravimetrijske i geomagnetske metode, Univerzitet u Beogradu
2.
Vukadinović M. (2011), Primena geofizike u arheologiji, Zavod za zaštitu spomenika kulture Kraljevo, Narodni muzej Kraljevo
Strength and strain mechanical observation using Holography Interferometry Antonio Brozičević Regional Centre for Talented Youth Belgrade II, Serbia
mechanicalcomponents.
1 Introduction Holography is a technique that enables three-dimensional images to be formed. Holography, with its unique depth of field and interferometric capabilities, is a powerful new tool for the study of strength and strain properties of materials. Strength and strain of materials are very important physical characteristics. Each material havedifferent physical properties. In our modern world those characteristics are very important for materials and their applications. Holography enables us to observe their unique characteristics and their weak points.In this observation we test various materials throughout Holography Interferometry technique. Holography provides very accurate results, which are essential for complex material analysis.
2 Purpose of Investigation The purpose of investigation is to analyze and investigate various materials and their mechanical and physical properties using Holography Interferometry technique. Holography enables three- dimensional observation of materials, which is very essential feature for complex material examination. This technique will significantly improve our understanding of materials properties, and their weak points. Also this technique provides very fast and accurate results, which can be used as essential diagnostic tool for material study.
3 Method of the investigation A Schematic view of the real-time holographic setup is shown in Figure 1. Long coherence length, 532 nm second harmonic Nd-YAG, laser was used. A beam was split and one beam was used to illuminate a material, while the second beam was utilized as a reference to irradiate the holographic plate (VRP-M green sensitive emulsion, produced by Slavich, Russia). Materials and components used in this investigation are dental composite resins, and mechanical components used in industry. Mechanical components are different types of gear wheels, bearings, and various metals. Mechanical components are exposed to different mechanical stresses and observed trough interferograms.Dental resins used in this investigation arelight –activated, which cure and quickly harden when exposed to specific light spectrum.Blue LED, (450-480nm wavelength) lamp is used to activate resin. It was necessary to use filters, in order to reject LED lamplight, and transmit 532 nm interference patterns.CCD camera and computer detected and recorded the interference pattern of resins and
Figure 1.
4 Results of investigation These results characterize holographic real-time measurements and analysis ofmaterial hardeningand different types of mechanical stresses. While hardening process take place we analyze mechanical properties of dental resins. A series of 10 experimental samples were analyzed. We conclude that all 10 samples, which varied in their size, results obtain pretty much the same values without any large oscillations between samples. Throughout interferogram analysis we conclude that at the beginning of process during first seconds after material is lightened there is no recognizable change, after about 10 second obvious difference can be observed. The maximum deformation is attained at the end of process. From results we conclude that resin deformation starts to travel down from the place were it is lightened, and start to contract material which is around. Different types of mechanical components such as gear wheels, which are tested,have certain points where they excerpt more stress points then on other places. Also every type of mechanical component have their own weak points. Every mechanical component that was observed have their own properties that enable usage in specific area of industry. 5 Conclusion These experiments represent results of holographic realtime measurements of dental resin structure deformations and mechanical components deformations.Physical stresses which acts on them are observed thru ought interferograms. This technique enables testing of various mechanical components, photosensitive resins and materials, with the aim to improve their mechanical properties. This technology could significantly improve materials in future, which will be more permanent and durable. 6 References [1] MilesaSrećković“LaserskaTehnika”, (Serbia) Belgrade, 1998
Optimization of electron gun Katarina Radinović Kapralović Center for talented youth Belgrade II, Belgrade, katarina.radinovic.k@gmail.com
1. Introduction In atomic phisics measurements that utilize crossed beam experiments with electrons as projectiles, it is very important to have a well-defined both the geometry and the energy of the electron beam. If the experiment does not require a very high energy electron resolution, electron gun can be used as an electron source. Most commonly, the electron gun consists of a flat /or a hairpin) cathode that emits electrons through thermo-electron emission, as well as of a few additional cylindrical cathodes. The latter are used to achieve a precise beam geometry, a good focusing at a desired distance and for setting the electron beam energy. A difference of the potencial of the cathode and of the last electrode defines the electron beam energy, while the energy resolution is defined by a thermal distribution of electrons emerging from the cathode (usualy about 0.5eV). Furthermore, various applications and time of flight dependent experiments require an usage of a pulsed electron beam, in order to sequence the measurements.
2. Methods In this study we have made a model in SIMON8[1] of an electron gun. We present the results of a 1MHz pulsed operation mode, with 5ns, 10ns and 20ns pulse widths. We have performed voltage optimization for the range of (11000)eV electron energy, allowing theoretically to preserve the focal point at a fixed distance of 40mm from the exit aperture, in the continuous mode of operation, and with an influence of the Coulomb repulsion between electrons. Furthermore, we descrebed Pierce’s electron gun design method in order to obtain optimized electron gun and electrodes shape.
two electrons with initial energy of 0.1eV from Y=0.5mm and Z=0mm (Xis the axial direction).
Figure1(left) - 3Dmodel image from SIMON8[1] of electron gun and geometry of its electrodes. Figure2(right) - Potential energy (grey) from SIMON8[1] of the electron gun and electron beam trace (black). Pulsed mode of operation was achieved by applying a time dependent voltage on the Wenelt electrode E1. We analyzed Pierce’s electron gun design method using the properties of complex functions and Laplace equation to find the optimized electron gun and electrodes shape.
3. Results The first step in the simulation is to define a desired electron optics geometry and its electric potentials via special programming code, which creates geometry file. The program then solves the Laplace equation for the electric potential and calculates the electric fiels defined by gradient of that potential by using a method of finite differences. This process gives the solution for the electric field in an empty space between electrodes. After having defined the electric field, desired changed particle initial conditions can be defined and the program solves differential equations of motion. In the final step, the program displays particle trajectories. All remaining electrodes have fixed voltages, except for the E1 (in the pulse mode). All electrode voltages are set relative to the cathode, in order to keep the electron gun’s primary electron extraction lenses at nearly the same focusing capabilities, while changing through electron energies. The voltage on the electrode E4 was optimized via special iterative LUA programming code in SIMON8[1], in order to obtain minimal possible beam radius at the distance of d=40mm, from the last electrode E5. This is simulated for
Figure3 - Pulsed voltage time shape of one full period of 1MHz pulse on electrode E2. Voltages b and a are arbitrary on and off trigger voltages respectively.Pulse with and slope grades are defined with simulation variables t 1 , t 2 , t 3 and t 4 .
4.
Conclusion
Program SIMON8[1] was used for simulation of a commercial electron gun working in both continuous and pulsed mode. We investigated a possibility of obtaining a fixed focal point in a wide energy range by tuning only one electrode potential. Also, we presented in this study a possibility of turning from the continuous into pulsed mode of operation by setting a pulsed voltage on the Wenelt electrode E2, down to nanosecond pulse width and 1MHz repetition period. Having analyzed Pierce’s electron gun design method, we obtained one type of cylindrical gun that we can designe analitically.
Refrences
[1] M. Lj. Ranković, M. Čeklić and A. R. Milosavljević: Optimization of electron gun in continuous and pulsed operation modes. (2013) [2]Stanley Hamphries, Jr.: Charged Particle Beams (2002), (263-270)
PSYCHOLOGY
The presence of playing video games among the high school students Slađana Vlatković Center for talented youth Vojvodine, sladjanavlatkovic@gmail.com
1. Introduction We live in a time in which the computer is component part of our lives. Also playing games is an increasingly popular activity. Over time they have become part of their personal and social lives of young people, contributing to the development of different relationships between people as well as changing perceptions towards the concept of entertainment. By itself, this activity is not harmful, if not lead to dependency. In people it can affect the development of a range of skills such as learning, quick thinking, memory... Contrary to what playing games can affect the increasing aggressiveness, anxiety and violence, which can become an important factor in the formation of personality. The research problem is defining the presence of playing video games among the high school students. The aim of this research is to spot presence of playing video games among high school students depending on gender, school and success.
by the greater adaptability of the content in video games to the personality of males. The connection was spotted between the school that the subject is attending and the school that the subject is attending and the time that he can spare for this activity, from which we can assume that the students of Grammar School, due to range of lectures and the high demands, have less time and therefore they play games less. Also, the 58, 2% of the subjects have no feelings after a defeat in games. It can be assumed that this result was achieved because the subjects weren’t taught to recognize their feelings during their development. Also, the additional explanation can be that the subjects do not want to acknowledge their true filings, because that would show the effect that games have on them. According to research why the respondents play games is boredom, and the everyday problems that young people are burdened. The output from these everyday problems they found in the imaginary world of computer games.
4. Conclusion
Picture 1- Young people who play games
2. Method The applied work method was the systematic nonexperimental research and the technique was anonymous questionnaire constructed for the purpose of research under the name ,,Gaming fever“. The questionnaire that the subjects who were questioned filled in the internet and traditional form were constructed of 22 questions which referred to the opinions of the subjects who were questioned about computer games. The research was conducted on the sample of 173 subjects, students of the Grammar School and the Technical High School in Sombor, which were equally present in gender, class and school. The processing of data was conducted in Microsoft Office Excel 2007, using descriptive statistics.
3. Results The research results have shown that the video games are played more by males then females. That could be example
From early childhood, it is necessary to point out to children at the pros and cons of playing video games. The parents and the environment in which people live are important factor that influences. It is necessary to set time limits, and create habits that this activity is performed only after the execution of daily activities. There by reducing the risk of dependency. It is very important and choosing the content game. Preferably, the games have educational content, such as thinking or strategy games, while games with violent content, such as war are considered harmful. These results open possibilities for research of the connection between the temper and playing games, as well as between playing games and addiction
References [1.] Grujić V. Ivana, Personality traits and internet addiction. Graduate work. Faculty of Philosophy, Kosovska Mitrovica, 2010 [2.] Đorđević Anita, The psychological profile of internet addicts. Professional work. Institute for Strategic Research, Belgrade, 2011 [3.] Jevtić Ana and Savić Milomirka, Correlation between playing violent video games and bullying among adolescents in Serbia. original scientific work, . Faculty of Philosophy ,Belgrade, 2013
SOCIOLOGY
The existence of awareness among high-school students about possible (mis)use of information and communication technologies for the purpose of surveillance and control Nikola StanojÄ?iÄ&#x2021; Baba ViĹĄnjina 22, Belgrade
Introduction In the XXI century, sudden, exponential growth of information and communication technologies has led to a revolution in interpersonal communication. Location loses meaning as a dimension of social interaction, and time becomes almost negligible with the existence of a stable internet connection. One of the social groups which has accepted this growth the fastest are young people. However, the development of technology also carries the increased potential for its misuse. It seems that this question has further been actualised after the explosive growth of information and communication technologies. Simply by using them, people leave a personal, virtually indellible mark in the digital world. That in itself raises a question: are young people, as a group who have accepted technological growth the fastest, aware of the fact that those new communication tools can be misused? The goal of this research paper is to try to find an answer to this, and similar questions, on both empirical and theoretical grounds. The key research question that is being asked throughout this paper is whether young people are ready to sacrifice their privacy for the purpose of better permanent connectivity with the rest of the world, and above all, are they even aware of such a sacrifice.
Research methodology The research methodology of this paper consists of three equally important parts: theoretical framework, an analysis of the findings of other research papers and personal qualitative research using the method of in-depth interview on the population of high/school students. Combining these three levels of analysis has enabled the authos to reach a number of conclusions for the purpose of giving this paper a finishing touch. The author would also like to add that the research method of interview was chosen primarily for its depth and possiblity of focusing on details, which would be left out with the use of, for example, a questionairre or a survey.
Results of the research This research has led to a number of comclusions. First and foremost, is turned out that awareness about possible misuse of information and communication technologies indeed exists, but that it is not developed enough, or that it is sidelined in the favour of other things, primarily permanent connectivity with other people. This brings us to three general conclusions: 1) awareness of possible misuse does not exist, and individuals behave in accordance with the behaviour of their peers; 2) awareness of possible misuse exists, but individuals primarily choose to be part of the majority and ignore fears that their information can be misused, all for the purpose of better permanent connectivity; 3) awareness of pobbile misuse exists, and individuals act with caution or even refuse to use certain information and communication technologies, but that leavs them succeptible to partial marginalisation by their peers; In conclusion, the situation with which high-school students are faced is precarious. Although relatively aware of the loss of privacy which is waranted by the use of information and communication technologies, they are more inclined to involve those technologies in their daily lives. Are future generations a society that slowly gravitates towards the pursuit of better connectivity, and a lesser influence of individuals? Only time will tell. The purpose of this paper and abstract is to point out this phenomenon, and open the door for other research of larger scope and depth.