SC PE The Scientific and Technical Journal of The Haberdashers’ Aske’s Boys’ School, Elstree
2020 I ssue 31
Change
In anticipation of the new Decade Insulator or Superconductor?
The Slight Twist that Changes Future Technology
COVID – 19
A Global Pandemic
How Logistic Maps Changed the Way we Think
Letter From Editors Dear Reader, When we met for the first time, in the Autumn Term of 2019, it proved a challenge to find a suitable theme for Issue 31. There were no notable anniversaries of significant scientific discoveries, or a major technological breakthrough that we could commemorate. With the end of a decade fast approaching, TT Zhang suggested the theme of “change” in anticipation of 2020. At the start of the Spring Term, the deadline for submission, we received many high-quality articles on the theme of change but ironically, we had no sense of the momentous change which was lurking. With lockdown and a virtual school, the challenges faced meant that time passed faster than anticipated. Producing a magazine which excluded the most significant scientific event of recent times was inconceivable. Therefore, it is with sincere gratitude that we acknowledge the outstanding contribution of the four authors who provided the articles relating to COVID -19, at very short notice. Indeed, we thank all the boys, from across the year groups, who submitted a wide range of high-quality articles which span the three Sciences, as well as cutting-edge Technology and Mathematics. Coincidentally the article on Chaos Theory describes chaotic systems like the pandemic; where one person contracting a virus in Wuhan, China, results in the lives of around seven billion individuals being affected, due to a public health crisis, rising unemployment and collapsing economies. Although SARS-CoV-2 is an agent of death and doom affecting humanity, it was felt necessary to have an artist’s representation of the virus on the cover of SCOPE 2020, as we look to Science for a solution in the new decade. TT Zhang Rishi Virani Seren Grant
Dr A. Perera Staff Editor
The Haberdashers’ Aske’s Boys’ School Butterfly Lane, Elstree, Hertfordshire WD6 3AF Telephone: 020 8266 1700 Registered charity no: 313996
SC PE
2020 I ssue 31
The Scientific and Technical Journal of The Haberdashers’ Aske’s Boys’ School, Elstree
Contents 2
18
30
46
Letter From Editors
Insulator or Superconductor? The Slight Twist that Changes Future Technology
Huntington’s: A Disease Characterised by an Altered Brain
How did Concorde Change Modern Aviation?
By TT Zhang, Rishi Virani, Seren Grant and Dr A. Perera
4
By TT Zhang L6S1
By Adam Smith 8H
By Theo Silverbeck L6S2
34
50
By Sohan Das 9S2
Can we Envisage a Future where Viruses Replace Antibiotics?
Scientific Research Work Experience Report
22
By Daniel Goldstone L6S1
By Nirvan Marathe L6C2
6
Changes in Environment and Behaviour - Darwin’s Theory in the 21st Century?
8 How does SARS-CoV-2 Attack the Body? By Roshan Patel L6H1
10 The Immune Response to COVID -19 By Alex Joseph L6M2
12 The Development of Vaccines in the Fight Against SARS-CoV-2 By Sacha Holt L6M2
The Change in the SI Units
By Veylan Sebastian 11J2
Daniel Malekyazdi L6R1
By Gautham Arun 7C
38
54
26
The Emergence of Lithium as a Possible Solution to the Global Energy Demand
The 2019 Nobel Laureates
24 Cassini-Huygens’ Legacy Lives On…
Robotic Plants: How Technology is Revolutionising Botany
Summary: COVID – 19 - A Global Pandemic
28
How Accurate are Mathematical Models in Predicting the Magnitude of COVID-19? By Krish Nanavati L6R1
52 Engineering Work Experience at a Global Aerospace Defence Company
By Lucas Valladares 11H1
16
36 How has the Universe Changed Since the Big Bang?
By Shiv Choraria L6C2
15 By Roshan, Alex and Sacha
48 Are Humans still Evolving?
20
By Roshan Patel L6H1
32
By Ojas Sharma 8S2
A Star is Born
2020: A Year of Change
COVID – 19: A Global Pandemic Introduction
By Atharv Bibekar L6J1
The Amplification of a Small Change: The Physics of Chaos Theory By Krish Nanavati L6R1
55
By Phalgun Deevanapalli 8R2
Citations
40
63
How Logistic Maps Changed the Way We Think By Rishi Virani L6J1
43 How Hypersonic Weapons Will Transform Modern Warfare By Jitong Zhou 11H2
WHO world map
2020: A Year
of Change
COVID – 19: A Global Pandemic Introduction By Roshan Patel L6H1
6
severe acute respiratory syndrome (SARS)-like
A
cases in the UK leading to 44,220 deaths . As SARS-CoV-2
coronavirus called SARS-CoV-2 is causing the global
is transmitted through virus-laden droplets, coronavirus
pandemic of COVID-19. First identified in late 2019
is easily spread through coughing or sneezing, especially
in Wuhan, China, SARS-CoV-2 has been spreading rapidly
when people do not wash their hands before eating or
throughout the world, especially in countries such as USA,
touching their face. Most people who contract the virus will
Brazil, India, Russia and UK. As of 6th July 2020, there
experience moderate illness and will recover without any
have been over 11 million cases world-wide, with 285,000
specialist treatment needed. However, people who are more
COVID – 19: A Global Pandemic - Introduction
Figure 1 List of common symptoms of COVID-19
at risk, for example the elderly and people with underlying health conditions, are likely to develop severe symptoms. According to Nature, the current infection fatality rate is between 5-10 per 1000, or 0.5%-1%, which includes those who do not show symptoms as well as those who have an extreme reaction to the disease . Despite this, some countries are showing higher fatality rates due to demographics, such as an older population. As similar outbreaks have occurred before, namely MERS-CoV and SARS-CoV, there is an urgency for a better
Figure 2 Daily new cases of COVID-19 from January 22nd to 5th July
understanding of the mechanism by which SARS-CoV-2 infects the body and causes such widespread harm. In addition, there is still uncertainty surrounding whether your body can gain immunity from the virus: if you get it once, can you get it again? In this review we will focus on how SARS-CoV-2 enters and attacks the body, propagating through cells in the lungs. We will also describe the immunological response to the virus: the innate and adaptive immune responses. Finally, we will discuss the potential for a vaccination, following the progress of certain methods, and whether they will in fact provide immunity. Figure 3 Artist’s representation of viral spread
COVID – 19: A Global Pandemic - Introduction
7
How does SARS-CoV-2 Attack the Body? By Roshan Patel L6H1
S
ARS-CoV-2 is a single-strand plus-strand RNA
cell’s membrane, and releases its RNA genome into the cell.
virus, meaning rather than having DNA like other
Alternatively, the virion can enter the cell by endocytosis,
organisms, its genetic information is coded in a
when a cell surrounds a particle which fuses with the cell
single RNA strand. It has a spherical structure, surrounded
surface membrane to enter the cell in a vesicle.
by a lipid envelope. Inside the virus, also called a virion, there is single stranded RNA surrounded by a protein shell called the capsid which protects the genome (Figure 1). Around the capsid there is a larger membrane containing many types of proteins, perhaps most importantly the spike proteins. These appear like clubs, producing a crown effect which gives coronavirus its name (corona meaning crown in Latin). The spike proteins are essential for infecting the cell since they act as a key, allowing the virus to enter the cell by binding to the human receptor angiotensin-converting enzyme ACE2 through their receptor binding domain (RBD). Once the spike protein binds to ACE2, a protease enzyme called TMPRSS2 helps the virion enter the cell [1]. The virion then dissolves its own protein membrane, fusing with the
8
How does SARS-CoV-2 Attack the Body?
Figure 1 Structure of SARS-CoV-2
formed virions being produced, they are released from the cell surface by budding [4] .
Figure 2 Artist’s representation of SARS-CoV-2
Figure 4 Diagram of an alveolus under severe symptoms
When someone is first infected, viruses would most likely infect cells in the lining of the nose where there is an abundance of ACE2 expression [5] . Once the virus has multiplied and proliferated, people start to “shed� virusladen droplets through coughing for example [6] . If the immune system does not act fast enough, after the initial Figure 3 Mechanism of entry and replications of SARS-CoV-2
Once the virion has entered the cell it releases its genome which can be translated into proteins, similar to mRNA. This is because mRNA is complementary to the host DNA and is given a positive orientation as a convention of virology, meaning viral RNA can also act as mRNA as it is positive strand orientated. Therefore, the viral RNA can be translated into replicase, known as viral polymerase, a catalyst which can replicate the viral genome so more virions can be made [2][3] . This protein is known as an early protein since it is translated early as it is essential to the replication of viral nucleic acids. Once replicase has been synthesised, a complementary negative strand to the positive genome is formed by RNA replication. From these positive strands,
phase the virus will start to spread down the trachea and reach the lungs, at which point the infection can become deadly. From preliminary studies, epithelial cells which line the airways, and alveolar type II cells, which release surfactant to keep the lungs moist, have been shown to be widely infected in patients. These cells undergo apoptosis, a programmed cell death due to the stress caused by the virus. Therefore, the alveoli, which are involved in gas exchange, become damaged, reducing their efficiency in allowing oxygen to diffuse into the blood and carbon dioxide to diffuse out. Oxygen levels in the blood then drop drastically, leading to patients struggling to breathe unless aided by a ventilator. Over time the alveoli become filled with white blood cells, mucus, fluid and dead material of destroyed cells, which leads to death.
mRNA can be transcribed to form proteins which make the
So far, this review has focussed on how SARS-CoV-2 enters
capsid and protein membrane of new virions (late proteins),
and kills cells. Next we will look at how the body fights
or negative strands could be used to form new genome
back. We will discuss the role of both the innate and specific
copies. Structural proteins and RNA are assembled together
immune response in controlling viral infections, and how
to form whole virions by the Golgi Apparatus, an organelle
each facet of the immune system is essential to recovery.
which modifies proteins in eukaryotic cells. Thus, with fully
How does SARS-CoV-2 Attack the Body?
9
The Immune Response to COVID -19 By Alex Joseph L6M2
G
enerally speaking, there are two possible responses to COVID-19, the first of which would be the innate immune response. This route is in many ways a generalised anti-
viral response and is often described as the first line of defence against any infection, not just coronavirus. This begins with the physical lines of defence including the skin and respiratory tract, which act as physical barriers to the disease. Should this be bypassed, methods such as coughing and sneezing are then employed in an attempt to expel the virus particles. Figure 1 Skin barrier
10
The Immune Response to COVID -19
Figure 2 Inflammation
If the disease reaches its target, immune cells (e.g. dendritic
the virus is detected, a specific molecule on its surface (known
cells) attempt to detect the virus through patterns in its molecular
as an antigen) converts detector cells (e.g. dendritic cells) into
structure (known as PAMPs) [1][2]. Once detected these receptive
Antigen Presenting Cells (APCs), which effectively advertise the
immune cells also known as APCs (Antigen Presenting Cells)
virus. This activates a separate branch of immune cells known as
advertise the location of the virus, so that large phagocytic
CD4+ and CD8+ (T-cells) which bind to APCs via their MHCs (Major
cells are able to travel towards the infected area [3]. Some of
Histocompatibility Complexes) [9]. The CD4+ cells are then able
the phagocytic cells, including monocytes and neutrophils, are
to progress the activity of surrounding immune cells, whilst CD8+
involved in killing parasitic cells, whilst the monocytes are able
cells neutralise the virus through the release of cytotoxic proteins.
to release small molecules known as cytokines, which act to
Although this process is particularly effective, as shown by the
trigger inflammation; this can be helpful in preventing further
fact that vaccinations are trying to mimic it, evidence from MERS-
infection [4] [5].
CoV-2 (a genetically similar virus) suggests that coronavirus
Although this innate bodily response can be effective, it is often
could be inhibiting this response [6]. Looking at MERS- CoV-2,
overcome by the virus. Similar to its predecessors, it is believed
APCs often seem to almost go missing when other immune cells
that the SARS-CoV-2 virus which is responsible for COVID-19
are inhibited, therefore limiting this response. Seeing as we have
might have the ability to inhibit a variety of immune cells. Should
evidence of COVID-19 disabling macrophages and other immune
this prove true, then the innate immune response is rendered
cells, it is then possible that APCs have a reduced presence in a
ineffective, as there is no immune cell to act upon the recognition
patient with COVID-19. A reduced APC content ultimately limits
of the virus. Furthermore, data from testing in Wuhan has revealed
the concentration of plasma cells and T-cells, therefore limiting
that patients requiring ICU (Intensive Care Unit) generally had
the efficacy of the adaptive immune response.
higher levels of innate cytokines in their blood [6]. This suggests evidence of the virus triggering a “cytokine storm�; an excess release of cytokines which tends to harm the body more than help it. This idea is consistent with evidence that extreme cases reported high levels of cytokine-producing immune cells [6]. Aside from the innate immune response, there is also the adaptive immune response, which centres more around the specifics of the disease [7]. Unlike the innate immune response, which is a much more general approach, the adaptive immune response tries to understand the mechanics of the disease and therefore prevent its growth. This response can be split into two categories, the first being humoral [8]. The humoral response is enacted by larger molecules in extracellular fluids (e.g. plasma), including antimicrobial peptides, as well as antibodies. In the case of COVID-19, antibodies are produced by plasma cells (type of white blood cell) and will bind to the virus and neutralise it by causing it to burst. The second response, known as the cellular response, is coordinated by T cells- a type of white blood cell. Initially, when
Figure 3 Main cells involved in adaptive immune response
The Immune Response to COVID -19
11
The Development of Vaccines in the Fight Against SARS-CoV-2 By Sacha Holt L6M2
W
e have previously spoken about how SARS-CoV-2
a disease [1]. At this point, the process moves onto the pre-
attacks the body, and how the immune system
clinical stage. Here, tissue culture cell samples are treated with
responds. This section will focus on the development
the potential vaccine, as well as small animals (often mice and
of vaccines against the virus, involving the process behind their
monkeys) to examine whether or not the antigen has the ability
production and clinical trials, as well as the most promising
to provoke an immune response [5][6]. If successful, it gives
current vaccine developments. There are presently 155 SARS-
scientists a starting point for understanding the dose of the
CoV-2 vaccines in consideration.
pathogen and the best method of administration. As of early July,
The vaccine development process starts when natural or artificial
there are 129 SARS-CoV-2 vaccines in this stage [1].
antigens are discovered which could have potential to treat
12
The development of vaccines in the fight against SARS-CoV-2
If the pre-clinical trials are successful, the vaccine moves into
introduced into the body, the vaccine provokes the production
Phase 1 where currently 15 potential SARS-CoV-2 vaccines exist
of complimentary antibodies to the antigens on the cell surface
[1]. These are the first sets of human trials with a sample size
membrane of the ChAdOx1 nCoV-19 by B lymphocytes [3][7].
between 20-80 where the effects of the vaccine on the human
These antibodies essentially mark the vaccine for consumption
body are examined. Here, the safety of the vaccine and the
by macrophages and inhibit the antigen’s function by destroying
extent of the immune response it incites is inspected. This is
the virus. This is known as the primary immune response.
further measured, along with dosage, immunisation schedules
Memory T and B cells have the capacity to ‘remember’ the
and delivery method in Phase 2 – currently only 9 vaccines have
production of these antibodies in the event of future infection,
progressed this far [5][6].
so if SARS-CoV-2 enters the body, antibodies can immediately be
There are at present only 2 vaccines which exist in Phase 3, which if successful, will most likely allow the vaccine to be used worldwide. Here the sample size involves tens of thousands of humans. This allows for any rare side effects and abnormal immune responses to be identified which wouldn’t show up in the smaller trial sets and provides evidence that the vaccine is
produced which allows for the virus to be destroyed [2]. This is known as the secondary immune response and happens much faster than the primary immune response, ensuring the virus has no chance to invade host cells. This vaccine has just begun Phase 3 trialling in South Africa and Brazil, and if it is successful, it may well be the first vaccine to be released to the general public [2][7].
safe for general use. Optional extra stages can exist after this
Another potential vaccine is being developed by Moderna (an
to analyse the vaccine’s efficacy further, but due to the current
American biotech company) and NIAID (The National Institute of
demand for the vaccine this will most likely happen alongside the
Allergy and Infectious Disease). Moderna are pioneering a much
mass distribution of the treatment to the general population [6].
more novel method of vaccine production and are currently in
One of the most promising vaccines is being developed in a
Phase 2 of development. Their vaccine is known as mRNA-1273
collaboration between Oxford University and AstraZeneca (a
[9]. Using genome sequencing, they were able to identify the
British-Swedish multinational pharmaceutical company). Their
sequence of RNA (the virus’ genetic information) which coded for
vaccine is developed from the ChAdOx1 virus, which is essentially
the distinctive spike proteins on the outside of the SARS-CoV-2
a weakened and non-replicating form of the common cold
virus. This small section of RNA was then encoded into a piece
(adenovirus)[2][3]. This virus has been engineered to express
of messenger RNA (mRNA) which essentially allows this genetic
the SARS-CoV-2 spike structure identically by incorporating
information to be read by ribosomes. This mRNA can then be
spike glycoprotein, forming the ChAdOx1 nCoV-19 vaccine. When
injected directly into the patient to provoke an immune response.
The development of vaccines in the fight against SARS-CoV-2
13
14
When the mRNA enters the body’s lymph nodes, it instructs
their use will likely be much more prominent in the near future.
immune cells to produce the spike proteins on their outer cell
There are concerns that vaccinations against SARS-CoV-2
membranes, as if they had been infected by SARS-CoV-2 [9]
might not actually provide long term immunity [11]. Scientists
[10]. This enables B lymphocytes to produce complimentary
are unsure how the combination of antibodies, cells, and other
antibodies to the antigens on the spike proteins. Very similar
markers in a person’s blood will dictate their level of immunity. It
to the process mentioned previously, memory T and B cells
is known that some level of immunity is provided for an unknown
are then able to ‘remember’ how to produce these antibodies
length of time, but other factors such as viral mutations may
to fight against future infection from the virus. Moderna have
affect this drastically. There is also some debate concerning the
already begun production of this vaccine (subsidised by the US
danger that these vaccines have to the body, especially the mRNA
Government) despite the fact it has not been cleared for general
vaccines due to their novelty. Vaccine development for SARS-
use, which is a significant risk but means that if the vaccine is
CoV-2 has been the fastest ever, and this is a testament to the
successful, the infrastructure is already in place to mass-produce
significant advances in scientific research over the past decades.
the vaccine [12]. No mRNA vaccine has been approved before
The only chance that the world has in returning to some sense of
for an infectious disease as it is such a novel approach, however
normality is the widespread distribution of an effective vaccine.
The development of vaccines in the fight against SARS-CoV-2
Summary: COVID-19 A Global Pandemic By Roshan, Alex and Sacha
T
hrough our review, we have illuminated the science
similar viruses. More research into the immunopathology of
behind the COVID-19 pandemic: how SARS-CoV-2
SARS-CoV-2 is needed, especially in studying how COVID-19
impacts the body, how our immune system responds
affects people with underlying health problems such as
and how we can develop treatments to protect ourselves.
heart conditions and diabetes.
We have seen how SARS-CoV-2 is structured, and how it
Finally, we considered the process behind vaccine
is dependent on ACE2 receptors to bind to the cell and
development and two of the most promising current
release genetic information. However, more information
candidtes. Oxford University and AstraZeneca are developing
is needed to map the expression of ACE2 receptors across
a vaccine which revolves around modifying the common cold
the body to pinpoint which areas are most affected, aiding
virus to express the SARS-CoV-2 spike protein structure
targeted treatment options. Moreover, there has been
to allow the body to produce complimentary antibodies.
greater information provided about the possible impacts
Moderna and NIAID are also developing a vaccine which
of COVID-19 on the heart, brain and gut. Having identified
incorporates a much more novel method involving mRNA.
mechanisms and structures of the virus, we will be able to
This type of vaccine has never been approved for use in
act faster if a similar case presents itself in the future.
combatting infectious diseases, a high risk, high reward
We have also discussed how the immune response to SARS-
idea which may pave the way for future vaccine production.
CoV-2 can be divided into two categories: the innate immune
There is uncertainty surrounding whether a vaccine can lead
response and the adaptive immune response. The innate
to someone developing prolonged immunity to SARS-CoV-2,
immune response acts as a first line of defence to prevent
casting doubt on whether the vaccine will halt the spread of
infection through methods such as coughing and sneezing.
this pandemic.
To contrast, the adaptive immune response attempts to
As SARS-CoV-2 continues to spread, we must endeavour to
prevent the infection from spreading. Although treatments
expand our knowledge about its transmission, mechanisms
have been proposed, it would seem that the virus is able
of infection, immunopathology and how we can develop
to inhibit the innate immune response, and to some extent
vaccines. We must learn lessons from this period and work
the adaptive immune response, similar to other genetically
to prevent a second pandemic from appearing in the future.
Summary: COVID – 19 - A Global Pandemic
15
How Accurate are Mathematical Models in Predicting the Magnitude of COVID-19? By Krish Nanavati L6R1
16
Introduction
However, the effectiveness of these models has been
The 2019 coronavirus pandemic, which became a global
questionable throughout the crisis. Although there have
issue at the end of last year, has resulted in potentially the
been many different models made, with varying degrees of
most devastating crisis since the Second World War. As of
success, none have been as accurate as desired.
13th July 2020, over 13 million individuals are confirmed to
What are mathematical models, and what types are used?
have been infected with the virus, with more than 570,000
A mathematical model is a formulation which takes some
deaths (Figure 1). It has been one of the most significant
initial conditions and some set parameters, which in turn
widespread virus outbreaks since the H1N1 Spanish Flu of
produces a value that varies, in this case, over time [3]. They
1918 [1].
are usually deterministic, which means that the model will
In order to chart, record and predict the growth of the virus,
produce a specific value for an input, that is completely
mathematical models have been deployed extensively. Their
reliant on the parameters of the model. However, there are
most prominent use is to influence government policy in
other models which are stochastic, which is a way of adding
order to combat the virus. Some examples of the strategies
in inherent randomness into the model. A simple example of
used include lockdowns on the national and local scales, use
this is to multiply a random variable to the model, this gives
of face masks and social distancing.
it an unpredictable value, making it more realistic [4].
How Accurate are Mathematical Models in Predicting the Magnitude of COVID-19?
Some of the simplest models are standard deterministic
By the latter metric, the models have not been successful.
functions, such as an exponential model. These tend to be
Scientific advice has failed to control the virus effectively,
quite accurate, but only for a short period of time. In the case of an exponential model, which only tends to be reliable for the initial stages of the transmission when the virus spreads from one person to another very rapidly. However, with time the virus begins to spread slower as the susceptible population becomes smaller and smaller, so the exponential model is not very effective. Instead, logistic models and curves, seen in Figure 2, are a better way of modelling virus transmission. The beginning appears to be exponential, but it continues to slow down and eventually level off to approach a limiting population. This is a better model, as it more accurately represents how you might expect a real virus outbreak to behave. Another option, which could be used as a deterministic or stochastic model, is SIR or SEIR modelling (Figure 3). This involves splitting up the entire population into Susceptible, Infected and Recovered, and then creating different functions to predict how an individual may become infected and subsequently recover (from S to I to R) [5]. A more advanced model would include an Exposed category for those unknowingly infected and infecting others, whereas Infected would represent those infected, but isolating and not infecting anyone.
and early predicted number of deaths in the UK have varied from 66,000 to over 500,000 depending on the model used and the measures implemented [7]. The government’s own initial hope was a death toll below 20,000. There are many reasons for such discrepancies. The first is that it is very difficult to quantify some of the external factors that affect virus spread. Some of these include the efficacy of the healthcare systems and how strictly the public adhere to social distancing and lockdown rules. Predictive models find it difficult to guess these factors in advance, and to create a model parameter based on these variables is almost impossible, which could lead to poor estimates. Other problems include choosing which type of model to use. As discussed earlier, there are several potential options, and not one is definitively superior to the others. Different types of models could produce significantly varying results, leading to uncertainty. Moreover, it might be more appropriate to use a variety of dissimilar of models for different stages of the spread of the virus, adding even more to the complexity of forming the model and the range of outcomes. Finally, the novelty of the virus made it difficult to create early predictions for how the virus would spread. Key pieces of data, such as the R0 number of the virus (how many susceptible people are infected from one infected person) were unknown at the beginning of the crisis, and there remain questions concerning how upfront China was with information regarding the initial outbreak [8]. These are essential figures, and without them any models made initially could be significantly incorrect, for example, modelling a new outbreak of the flu is much easier since this data is well established and can be used with a high degree of reliability. This article is related to my Aske Project entitled “How
Why have they not been effective? All models are imperfect as there are a wide range of factors that affect virus transmission and it is impossible to account for all of them. However, these models are not expected to be exact predictions of the virus spread, but instead provide good estimates and especially allow for comparison of tactics and rates of transmission.
Accurate are Traditional Mathematical Models at Predicting the Growth of the 2019 Coronavirus Epidemic?�. The project centres on creating and testing a logistic model and delves into details about how to test model accuracy and the reasons for the differences in outcomes. It might be worth reading if you enjoyed this
How Accurate are Mathematical Models in Predicting the Magnitude of COVID-19?
17
Insulator or Superconductor? The Slight Twist that Changes Future Technology By TT Zhang L6S1
G
raphene, since its discovery in 2004, has claimed many
Prof. Jarillo-Herrero and his colleagues stacked two layers of
extreme properties unique to itself; it is the thinnest
graphene one on top of the other, with one layer rotated by
material in the world, a better conductor of electricity
1.1 degrees in respect to the other layer. The bilayer was then
than copper, it is also very light and hundreds of times stronger
compressed at a pressure greater than 10,000 atm, [3]. The
than steel [1][2]. However, in March of 2018, a group of physicists
resulting structure is known as a stacked bilayer and forms
at MIT, Pablo Jarillo-Herrero and his colleagues, found that this
a pattern of overlapping hexagons as shown in Figure 1. The
material has even more wonderous electronic properties yet to
bilayer is also able to demonstrate dual properties of insulation
be discovered.[3]
and superconductivity. Superconductors are materials that conduct electricity, by the flow of electrons or ions through the material, with no resistance. This means that there is no wasted thermal or sound energy when the superconducting material reaches its critical temperature, Tc, as shown in Figure 2.
Figure 1 Pattern of overlapping hexagons
18
Insulator or Superconductor? The Slight Twist that Changes Future Technology
Figure 2 Type I superconductors
The BCS theory (proposed by Bardeen, Cooper, and Schrieffer)
all when tested under normal conditions as shown in Figure
models the properties of type I superconductors (with a critical
3. Due to the fact that the bilayer structure behaves as a Mott
temperature below 30 K) [4]. The BCS theory states that when
insulator, [8]. These are a type of material which from their
the electrons are close to the Fermi level, which is one of
structures, appear to be conductors, but when tested behave
minimum kinetic energy approaching a temperature of absolute
as insulators. In fact, their energy bands (closely spaced energy
zero they couple up to form pairs called Cooper pairs [5]. The
levels) are half-filled with electrons, but because of repulsion
electron pairs can take the character of a boson and condense
between electrons, in different energy bands, ‘all the electrons
into a ground state, which is the state of minimum energy. Since
are blocked, so it’s an insulator because of this strong repulsion
Cooper pairs have a slightly lower energy then a normal electron
between the electrons, so nothing can flow.’ As explained by
pair, they can leave an energy gap above them on the order of
Prof. Jarillo-Herrero.
0.001 eV [4]. This prevents the Cooper pair from colliding with any other particles, which is what causes electrical resistance. Therefore, at extremely low temperatures, many materials demonstrate superconductivity. Type II, high-temperature superconductors, are mainly complex oxide ceramics which have critical temperatures above 90K. Discovered in 1935, they do not obey the conventional BCS theory of superconductivity [6][7]. Although 90K is very low, it
Figure 4 Adding electrons to a Mott insulator [Ifimac, 2015]
is achieved by using liquid nitrogen, which is a readily available coolant with a boiling point of 77 K.
Then, how can a material transform from an insulator into a
The significance of graphene’s superconductivity is that
superconductor? ‘It turns out the parent compound of most
although the system still needed to be cooled to 1.7 degrees
high-temperature superconductors is a Mott insulator’ answered
above absolute zero its behavior, under these conditions,
simply by Prof. Jarillo-Herrero [8]. Actually, his research group
is unconventional, and is very similar to the cuprate
formulated a very simple solution to this problem. Since the
superconductors (mixtures of copper oxide with other metal
bilayer graphene becomes a Mott insulator, under certain
oxides) [8]. This discovery was significant, as even though
conditions as all of the electrons in the structure are repelled
cuprate is considered a high-temperature superconductor, its
to the position of maximum separation; why not distort the
complex perovskite structure (similar to CaTiO3, commonly
existing structure with more electrons? Therefore, a small gate
found in type II superconductors) may ultimately lead to
voltage is applied to the structure, by introducing small amounts
understanding of high temperature superconductivity.[9].
of electrons. As the electrons were added, as shown in Figure
Conversely, the stacked bilayer graphene structure is relatively
4, the resistance of the graphene was also measured. It was
simpler and more easily understood. Just as Robert Laughlin,
found that when a certain number of electrons were added,
a physicist at Stanford University commented, ‘the stunning
the electrical current flowed without any energy being wasted,
implication is that cuprate superconductivity was something
just like a superconductor [10]. This discovery is potentially
simple all along. It was just hard to calculate properly.’
hugely significant. By establishing the conditions needed for
Nonetheless, the significance of this bilayer structure
superconductivity, it is possible to tune the graphene to either
of graphene does not end here. Primarily, this structure
insulator or superconductor, and even states in between,
demonstrated insulating properties before it could be turned
exhibiting the great diversity of application of this bilayer.
into a superconductor. As stated previously, a single layer of
Although the scientists cannot be certain that the
graphene is a very good conductor, this is because each carbon
superconductivity in graphene operates in exactly the same
atom forms three covalent bonds, and the fourth electron is
manner as cuprate superconductors, graphene-based materials
delocalised and is able to conduct electricity as it can move
still offer a much easier platform for researching the theories of
across the structure freely. As expected, within the bilayer
superconductivity.
structure of graphene, the energy bands are also partially filled,
The most obvious example would be that in order to measure
so in theory it should also be a good conductor. However, the
the superconductivity of cuprates, they need to be placed
bilayer structure of graphene does not conduct electricity at
under extremely high magnetic fields, yet with graphene, a slight change in the electric field will be sufficient to change its superconducting abilities. The discovery of the ‘magic’ angle of graphene symbolises a great advance in the study of hightemperature superconductors and as Laughlin says, ‘physicists have been stumbling around in the dark for 30 years, many of us think that a light just switched on.’ [3]
Figure 3 Conduction and valence bands in Graphene
Insulator or Superconductor? The Slight Twist that Changes Future Technology
19
Changes in Environment and Behaviour - Darwin’s Theory in the 21st Century? By Sohan Das 9S2
A
s we all know, the climate is changing. With that comes
shared between the polar bears present. Scientists had previously
environmental change. This alters the ecosystems in
thought of the polar bear as a solitary hunter, camouflaged into a
every habitat and the animals that live, hunt and breed in
white snowy background [1]. However, climate change has taken
them. There is no better time than now to consider what impact
away this once reality and made it just a vision. Now polar bears
adaptation will eventually have in the future. Could we be seeing
hunt on the rocks where sea ice used to reside, all melted as the
signs of Darwin’s theory of Evolution by Natural Selection in action?
temperature keeps rising, their ice-white fur clashing with the
A perfect example of adapting animals is
dark brown rocks on which they tread. They
the polar bear. On the BBC’s latest nature
are forced to hunt in packs like wolves in order
documentary-“Seven Worlds One Planet”- a
to survive, sharing their kills between those
group of polar bears were observed using a
they hunt with. However, putting this aside,
novel way of hunting beluga whales. In the
we may focus on the bigger change - their
Hudson Bay, Canada, polar bears were seen
hunting method. They used to grab fish out
standing on the few rocks jutting out over the
of the ocean, now they are forced to come up
sea level, waiting for beluga whales to pass
with a new way to catch their prey. Hudson Bay
near them. As soon as a polar bear finds
has a few rocks that just skim under or over
a target it deems easy enough to catch, it
the sea level, and the polar bears stand there,
leaps into the water, swiftly taking down its
stationary for hours at a time, demonstrating
prey. Such behaviour has rarely been seen,
levels of patience never seen before. Their
and even more shocking was that the kill was
20
Figure 1 Charles Darwin
Changes in Environment and Behaviour
underwater hunting ability is by far one of the
best on the planet, another product of evolution, and they use it to the full in killing their prey [2]. But why are the beluga whales even there? It is because the waters in the arctic are getting colder [3]. The whales seek warmer places to live when their home gets too cold, and the Hudson Bay offers that temperature, with river estuaries bringing warmer water from inland and dumping it into the Hudson Strait. However, migrating to the Bay comes with its dangers, as we have seen in the form of polar bears.
Another example of adaptation is the changes in coral bleaching with increases in temperature. Coral reefs are made from colonies of little animals called polyps. When polyps are overheated, they expel the colourful symbiotic algae that live within them leading to bleaching [4]. However, a study has found that only 20% of corals living in warmer waters expel their algae when heated, whereas 55% of corals from cooler waters bleached at the same high temperature [5]. The study moved some of the corals from cooler waters into warmer waters and found that when exposed to overheating only 32.5% expelled their algae, showing improved heat tolerance. This environmental adaptation is known as ‘phenotypic plasticity’. Phenotypic plasticity is how some animals and plants react to environmental changes [6][7]. It helps them alter their behaviour and change the timings of certain life processes to fit with the seasons and the temperature, as well as helping them to adapt to heat and cold. These are done through epigenetic changes, where the environment causes a gene to switch on or off by attachment of organic compounds to the DNA, without changing
and with temperatures on the rise, green sea turtles will go extinct locally at first, and if climate change is not slowed, then we may lose the species entirely [8]. Not all animals have the ability to respond to epigenetics, but those that do and reproduce quickly, pass on the ability to live in their new environment to their young, Darwin’s theory may eventually be applicable as these are the animals that will survive, and, unfortunately, those that don’t will become locally, if not globally extinct. In conclusion, I believe that Darwin’s theory could be relevant to adaptations to climate change and may lead to Evolution, over 5-10 generations, in some species. The changing environment is forcing animals to adapt, natural selection is at its most important time in history. Any animal that does not adapt will become extinct, sooner or later, and those that do adapt must keep doing so as the world is set for some major environmental changes in the coming years, decades and centuries.
the sequence of DNA. Sometimes, these changes are passed on to the next generation, but the changes are reversible and can occur multiple times during an animal’s lifetime. Often in migrating animals, or animals that travel to give birth, epigenetics play a key role in the timings of these events [6]. However, phenotypic plasticity is not always an advantage. Let’s take the example of the green sea turtles. The gender of green sea turtles isn’t decided through genetics, it is decided by the temperature of the sand in which the egg is laid. Warmer temperatures lead to the birth of females. Global warming means the temperature of the sand is increasing, leading to far more females being born than males, in fact, in the current younger turtle population, there are around 116 females for every male,
Changes in Environment and Behaviour
21
The Change in the SI Units By Shiv Choraria L6C2
T
he modern international metric system of scientific measurements, universally abbreviated to SI, originates from the French “Le Système International d’Unités”.
These are a set of units used by all scientists around the world in order to record measurements. The need for SI units is to enable research findings to be communicated and verified internationally. The fact that identical units are used universally makes data comparable and meaningful to the entire Global community. Measurements are always converted into their SI units before calculations are performed. The SI units were agreed upon in 1960 and now they are monitored by the International Bureau of Weights and Measures (BIPM) [1] [2]. When the SI units were first invented, they were all given definitions. For example, at present the definition of 1 second is “the time that elapses during 9,192,631,770 cycles of the radiation produced by the transition between two levels of a Figure 1 - All 7 SI Units
22
The Change in the SI Units
Caesium 133 atom” [3][4]. This definition for the duration of 1
As a consequence, in November 2018, the General Conference
second is via the use of a constant, which is not the case for all
on Weights and Measures agreed upon revising the definition
SI units. Without definitions of SI units for measurements like
of the kilogram. As of 20th May 2019, the kilogram is now
time, length or mass, we would not have a measure for how long
defined in terms of the Planck’s constant, which is exactly
a second is or how heavy a kilogram actually is. Furthermore, a
6.62607015x10-34 kg m2 s-1. This means that the kilogram is
second could be longer or shorter in different countries.
now defined in terms of the second and the metre. Along with
Another example is the definition of a kilogram. In 1889 a
this, the definitions of the ampere, kelvin and mole were all
cylinder of platinum – iridium became the standard unit of mass
subsequently changed.
for the metric system, known as the international prototype of
All seven SI units are at present defined in terms of naturally
the kilogram (IPK for short) [5]. This made the kilogram the last
occurring constants which means their values are essentially
of the SI units to be defined using an artefact. Essentially, all
fixed. These changes to SI units will not be noticed in everyday
metric values of masses were based on this ‘perfect kilogram’
life. However, within the scientific community these new
which is kept safely just outside of Paris. Multiple replicas of
definitions could turn out to be highly significant.
the platinum – iridium cylinder were also manufactured. These could substitute the original, if damaged. When the IPK and its replicas were cleaned, (using alcohol, ether and steam) their masses would change by small but measurable quantities (figure 2). This meant that the original mass of the kilogram was in doubt. As the difference in mass, before and after cleaning, was in micrograms the percentage change could be considered almost negligible. However, over time there was increased uncertainty of the 1 kilogram standard.
Figure 2 Change in the Mass of the IPK and its Replicas
Figure 3 Diagram to show the dependencies of the SI base units on seven physical constants, such as the kilogram now being fixed in terms of the second, speed of light and Planck constant
The new mass of the standard, even if considered negligible, would still affect the absolute value of the SI unit. This meant that, although the unit was used to make data universally acceptable, the numerical value of the SI unit itself was potentially changing, or even unknown.
The Change in the SI Units
23
Cassini-Huygens’ Legacy Lives On …
By Gautham Arun 7C
T
24
he Cassini-Huygens, one of the largest and heaviest
seafloor [2] [3]. Environments with similar conditions on Earth
interplanetary spacecrafts, has changed the way we look
support many different life forms so why not on Enceladus?
at Saturn and the Universe [1].
Little was known about Titan, the largest moon of Saturn,
NASA’s Cassini orbiter was aimed at the Saturn System while
before Cassini-Huygens. The discovery of tides, lakes and
the European Huygens lander landed on Titan, Saturn’s biggest
rainstorms on Titan was unexpected, as they were so similar to
moon. Because of these phenomenal spacecrafts, we now know
conditions found Earth. Hence, the first lakes beyond Earth were
that the Saturn System could hold the greatest secrets of our
discovered on the 14th January 2005 when the Huygens probe
Solar System [1].
landed on Titan. However, due to the very low temperatures on
In 2004 Cassini started its orbit of Saturn and the exploration of
Titan, the lakes were composed of liquid Methane and Ethane,
the planet’s many moons. Enceladus is the sixth largest moon
substances which are found as gases on Earth.[2] [3].
of Saturn and in 2005 Cassini discovered hefty geysers on the
Cassini also detected a storm that lasted almost twelve months
moon, which revealed a large subsurface ocean. The discovery
and was considered the biggest in the history of the Solar
of certain chemicals also suggests hydrothermal vents on the
System. In 2010 it measured temperatures reaching up to
Cassini-Huygens’ Legacy Lives On…
Figure 1 Artist’s concept of Cassini’s orbit around Saturn
Figure 2 Geysers on Enceladus
Figure 3 Cassini photographed the moon Io transiting Jupiter
Figure 4 A Jupiter flyby picture
around 66°C together with thunder and lightning. It was also
of debate with scientists [1].
noted that the storm spread 190,000 miles around Saturn, a
On the 30th December 2000 Cassini made its closest approach
distance equivalent to around 7.5 times the Earth’s diameter [2]
to Jupiter. Many mages of Jupiter’s faint rings and moons were
[3].
taken during the six-month flyby [1].
When Cassini flew past Saturn’s rings, it saw what scientists
The Cassini-Huygens final mission was to crash into Saturn
consider as a new moon forming. The discovery suggested that
while examining the planet’s atmosphere, sending data back
Saturn once had an even greater ring system and that maybe
to Earth till the very last second. On September 15, 2017, the
Titan and Enceladus could’ve formed in the tall structures found
spacecraft was destroyed, but its discoveries make way for
within the rings [1].
many more successful missions [1].
When Cassini became the first to orbit Saturn, it noticed that the
The Cassini-Huygens spacecraft had only one life but so much
planet has something unique and mystifying at its north pole
use was made from it that it is expected to benefit the next 100
no one has ever seen. It is called Saturn’s Hexagon. It is a slow
generations. That is what I love about Cassini-Huygens.
vortex of gases turning in a hexagonal shape. It is frequent topic
Cassini-Huygens’ Legacy Lives On…
25
Robotic Plants: How Technology is Revolutionising Botany By Lucas Valladares 11H1
F
or centuries botany has largely been a stable field with
and soil temperature. The plant rested on a robotic platform
regular, minor progressions. The idea of a robotic plant
which could move when it received an electronic signal by the
would be laughable considering the relatively minor
plant. When exposed to light from two lamps on either side of
improvements, in terms of sustainability and research into
the plant, the platform was seen to move towards the light [1] [5].
carbon sequestration and climate change. In December 2018,
Elowan was engineered with the aim of replicating natural
botany was revolutionised by a student at MIT called Hartreep
movement patterns of plants towards light. However, the wider
Sareen [1]. When “Elowan” a cybernetic plant (a plant in direct
objective of the experiment was to study and interpret the
dialogue with a machine) was revealed to the public, by the
circuits that transmit bio-electrochemical signals between plant
researchers Harpreet Sareen and Pattie Maes, it sent seismic
tissues and organs, with a view to replicating their efficiency
ripples throughout the biological community, spawning its
using electronics [2]. The physiology of living organisms could be
own discipline of ‘cyber-botany’ (augmented plants as sensors,
considered as almost mechanical. Therefore, it seems extremely
displays and actuators) which is continuing to grow to this day.
probable that future scientists will build artificial versions of plants.
The experiment performed by Sareen and Maes involved placing
However, Elowan demonstrates the combined capacity to innovate
silver electrodes into different tissues of a plant, including the
using the natural environment shared by scientists and engineers.
roots, in an attempt to amplify the bio-electrical signals produced
Elowan was merely a prelude to the new frontier of cyber botany,
by the plant in response to, for example, sunlight, tissue damage
26
How Technology is Revolutionising Botany
also known as ‘cyborg botany’. The new primary projects of
For now, cyborg, or cyber-botany remains an extremely
MIT centre around Phytoactuators and Planta Digitalis [3]
limited field. MIT appears to largely organise and control the
Phytoactuators, linked from the words phyto- (of plants) and
overwhelming proportion of research into this field. It further
actuator (a device causing other machinery to operate), are
seems that only one group is prepared to pursue the research
output devices which work via electrodes and electrical impulses.
especially with the controversy it has generated within the
The initial experiment was aimed at manipulating Dionaea
botanical community. From the demonstrations showcased to
muscipula, commonly known as Venus flytrap. The researchers
date, it is clear that the field has the capability to change botany
developed an app which would allow its user to effectively switch
permanently. It has the potential to transfer some of a plant’s
on the flytrap, utilizing its corresponding electrodes to trigger the
most crucial processes to real mechanical use, in a world where
flytrap to close its mouth. This capacity for a plant to be controlled
computer science and technology is gradually extending its
poses interesting issues.
influence in every aspect of our lives.
Planta Digitalis mimic the sensitivity of living organisms by
In 2018, ‘Elowan’ was introduced, the first of its kind. More
connecting a plant with electronic devices or instruments. Within
recently, 2019 brought Phytoactuators and Planta Digitalis.
the project, the team have grown a conductive channel inside the
Therefore, I pose the question, “how far will cyber-botany change
plant and implanted it within Propylenedioxythiophene, a water-
in 2020 and the decade beyond?”.
soluble polymer to allow its communication with other devices and hence its potential is effectively limitless [4]. The project demonstrated that these plants could be utilized to communicate human messages, using a language similar to Morse code. The plant conveys information from its surrounding through a “wire” implanted inside the plant, which in turn connects to other instruments like sensors of antenna. If the plant is able to detect movement, it could act as a movement sensor and transmit an alert to a mobile phone or any type of receiver used by either security systems or the military. There is also wider potential to revolutionize agriculture. Perhaps by designing self-spraying plants, growing with the exact quantity of water and nutrients, since the plant itself is responsible for monitoring and absorption.
Figure 2 This Plant Is Driving Its Own Robot”
How Technology is Revolutionising Botany
27
The Amplification of a Small Change: The Physics of Chaos Theory By Krish Nanavati L6R1
28
The Butterfly Effect
and whilst both are connected, they are distinct. Another
One very often quoted thought experiment is that of the
misconception is that chaos theory is, by its nature, completely
Grandfather paradox. If it were possible to go back in time and
disordered. Chaos theory is a mathematical formulation that
kill your grandfather, you would not exist in the future, so how
describes unpredictable or random systems which are governed
could you have gone back in time to kill him? A simpler version of
by deterministic laws (hence the name deterministic chaos).
this was explored by Stephen King in his book 11/22/63. Instead
Whilst at first this seems contradictory, there are plenty of known
of a person killing someone who directly affects their existence,
examples of this kind of behaviour. These systems tend to have
the time traveler prevented the murder of John F. Kennedy only to
extreme sensitivity to initial conditions and sometimes these
find the creation of a nuclear holocaust.
starting positions cannot be precisely controlled or measured.
This concept is generalised as the ‘butterfly effect’ where a butterfly
Chaos theory was first discovered by Edward Lorenz whilst
flapping its wings in the Amazonian jungle causes a hurricane
studying weather predictions using convection current theory
that savages half of Europe. Expressed in a more scientific way,
and this was when the butterfly effect was first explained.
a small change in the initial conditions of a system could lead to
The theory was an unexpected surprise as up until then many
an amplification of the output of that system. This phenomenon is
scientists, such as Laplace, believed in deterministic science.
linked closely to the theory of chaotic systems [1].
Which states that if we have the mathematical and physical
What is chaos theory?
understanding of a system we can perfectly predict its motion.
Some confuse the idea of the butterfly effect with chaos theory,
However, this kind of motion shows us that it is not true [2].
The Amplification of a Small Change
The Double Pendulum
involve some form of chaos theory governing them, from a simple
The simplest example of a chaotic system is a double pendulum.
system such as a bouncing ball, to four of Plato’s five moons that
Unlike a regular pendulum, whose behaviour is easy to predict,
rotate chaotically. In the quantum realm, there are many chaotic
a double pendulum is notoriously difficult to do so. It moves in
systems which can be applied to the field of electrical engineering.
random patterns and these patterns vary wildly depending on the
One example, which can be explained using quantum tunneling
starting position of both pendula [3]. The governing equations for its
and chaos theory, is the Josephson effect; where current flows
motion are: where θ is the angle made by the masses and the
for an indefinite amount of time across two superconductors
normal, m are the masses, l is the length of each pendulum,
separated by an insulating material [6]. Another is Chau’s circuit,
L represents the Lagrangian of the system (the difference
which demonstrates a more classical form of chaos theory as it
between the kinetic and potential energy of the system) and the dots
measures the output of an oscillator [7].
are the time derivatives of each quantity [4].
However, Chaos Theory also has many wide-reaching applications in other sciences. In biology the primary use of chaotic modelling is for predicting the growth of populations. Especially in the most advanced population models, where many starting conditions
This is an example of a system of partial differential equations which cannot be solved analytically using integration. Which
Figure 2 Josephson junction
means that there is no equation for motion which can perfectly predict a path of motion for the pendulum, hence the chaos in its
such as the initial population, weather patterns, temperature,
motion. The initial conditions here are the starting angles of the
food resources could potentially affect growth patterns that are
pendula, their length and the mass ratio of the two masses at the
very difficult to predict [8].
end of the rods. The sensitivity to these variables is very high and
There are also attempts to bring chaos theory outside of the
minor changes can amplify different variations.
natural sciences and into real-world applications, such as the
Whilst it is possible to approximate the motion of this system
modelling of traffic flows and encryption.
using methods such as the Runge-Kutta technique to give very
However, there is no confirmation that these applications are
accurate computer models of the path of motion, more complex
suited for chaos theory and hence should be used with caution.
chaotic systems are not so easily predictable, despite having similar equations of motion which define them [5].
Conclusion These chaotic systems are of considerable interest both for
Applications of Chaos Theory
their uniqueness and potential applications. It seems unnatural
Naturally, chaos theory has multiple applications within the fields
to us that such small changes can create completely different
of classical, quantum and theoretical physics. Fluid dynamics
outcomes, and the lack of predictability can often be seen as
is a significant area where chaotic modelling is used to predict
worrying but also highly useful for predicting future events, such
certain types of flows. However, most dynamical systems do
as a Global Pandemic, the result of a National Election or even consumer choice in the local supermarket. The possibilities are endless, and, in truly chaotic spirit, unpredictable too [9]. A significant and truly momentous example of Chaos Theory is what is currently being experienced, in 2020, by the entire Global community. How is it that one person in Wuhan, China contracts a virus in late December 2019 and the rippling effects of this single event are felt by almost seven billion individuals; not just in terms of lives lost or the creation of a public health crisis but the economic impact of rising unemployment due to collapsing economies.
Figure 1 The Double Pendulum
The Amplification of a Small Change
29
Huntington’s: A Disease Characterised by an Altered Brain By Atharv Bibekar L6J1 What is Huntington’s Disease? Huntington’s disease (HD) is a neurodegenerative disorder that reduces the function of the brain, over time, due to the destruction of brain cells resulting in the loss of brain tissue. The structures that seem to be particularly affected are the caudate nucleus and putamen, both of which are responsible for movement. [1] [3]. In addition, the disease also affects mood and cognitive function [2]. Huntington’s disease is a genetic disorder caused by the inheritance of a defect contained in a single gene. More precisely HD is described as an autosomal dominant disorder, which means that a person only needs one copy of the mutated gene in order to develop the disease [4]. Fortunately, the disease is very rare, occurring in 1-2 births per 10,000. Juvenile HD occurs in those below 20 years of age whereas adult-onset HD, which is far more common, occurs in adulthood. The effects are behavioural and psychological, manifesting themselves in symptoms such as chorea (random, uncontrollable, jerky movements) and depression. It is fatal 10 to 15 years after symptoms appear [3]. 30
What causes HD? The Huntingtin gene (HTT) is found in Chromosome 4, where the mutation causing HD can be found. The gene, HTT, codes for a protein called Huntingtin which is thought to be linked to neuronal function and development. The gene (HTT) contains a repeated DNA triplet of bases (CAG) which codes for, the amino acid, glutamine [4]. In a normal HTT gene the code repeats 6 to 35 times. However, when repetition is between 36 to 39 times HD is said to be at reduced penetrance, meaning that not all individuals with this number of repeats will have HD. However, if 40 repeats or more are present, HD would be expressed at full penetrance, which means every person with this length will develop the disease [1]. The more triplet code (CAG) repeats there are in the gene, the earlier the disease presents its symptoms. This is because an extended polyglutamine tract (repeated glutamine series) in the Huntingtin protein can cause DNA polymerase (enzyme in DNA replication) to have a greater chance of mistakenly copying an extra CAG triplet code. Therefore, the more CAG triplet codes you
Huntington’s: A Disease Characterised by an Altered Brain
Figure 1 Regions of the brain affected by HD
have to begin with, the earlier the symptoms of HD would appear [4][5]. It is thought that a larger Huntingtin protein, containing more than 35 glutamines, is degraded by the cell, leading to the formation of toxic polypeptide fragments that cause cell death [4][6][7]. It is unknown as to how the extension of the polyglutamine tract could lead to death of nerve cells. One theory suggests that it is due to excitotoxicity which involves the excessive signalling of neurones, which results in an increase in intracellular calcium ions that causes cell death [6]. What part do antisense oligonucleotides play? Antisense oligonucleotides are polynucleotides or sections of DNA that have complementary base pairs to the messenger RNA (mRNA) of the HTT protein. Hence, the antisense oligonucleotides bind to the mRNA before translation occurs, causing the HTT protein to not be synthesized. This either prevents the excitotoxicity of the nerve cells or the production of toxic polypeptide fragments. It does not correct the length of the polyglutamine tract in the Huntingtin protein but instead silences the whole HTT gene that codes for it [8].
the two highest dosages of IONIS HTTRx at 90mg and 120mg showed a decrease in Huntingtin protein levels by 40% [9][10]. Despite its seeming success, all that could be confirmed from the drug was that it was safe and able to successfully target the affected regions. It did not prove that the drug could in fact fully treat HD. This was mostly due to the difficulty in delivering the drug to its desired target. This was shown by how a 40% to 60% reduction of the Huntingtin protein in the cerebrospinal fluid only resulted in a 20% to 50% reduction of the Huntingtin protein in the caudate nucleus [9]. This occurred mainly due to the fact that IONIS HTTRx is difficult to distribute from the lumbar spine to the dorsal striatum. This is due to the presence of nucleases (enzymes that breakdown polynucleotides) and so much of the IONIS HTTRx is broken down before bonding to the mRNA in the dorsal striatum. Furthermore, the drug may bond to other mRNA molecules and hence inhibit the production of other proteins or affect their composition as there are over 50 other genes that contain a minimum of 12 CAG triplet codes. As HD is an autosomal dominant condition, the patient would still produce normal Huntingtin proteins that have 6 to 35 CAG triplet code repeats. Hence, an antisense oligonucleotide would still inhibit normal Huntingtin protein synthesis [4][10].
Figure 2 How antisense oligonucleotides function
The drug known as IONIS HTTRx is currently being developed to limit the production of the mutated Huntingtin protein, following a successful trial. IONIS HTTRx is an antisense oligonucleotide that is made up of 12 to 25 nucleotides artificially bonded together. The specific codon that corresponds to the CAG triplet code on the mRNA is GUC. By binding to the GUC codons, the drug could inhibit the synthesis of the mutated Huntingtin protein. In the trial, IONIS HTTRx was delivered through a lumbar puncture into the spine’s cerebrospinal fluid in the subarachnoid space, eventually allowing the drug to diffuse into the regions surrounding the dorsal striatum and the rest of the brain. In March of 2018, the published results showed a decrease in the concentration of the Huntingtin protein in patients with HD;
Figure 3 Normal brain and Brain with Huntington’s disease
In spite of the very recent strides in the development of drugs to counter a condition that seemingly had no cure, the function of the Huntingtin protein and its effect as a mutated protein is still inconclusive. Without understanding the fundamental cause of the disease, the premises for a cure fails. Regardless, time appears to be HD’s greatest threat, giving the disease a way to gradually consume our consciousness and trap us in a body that we cannot control.
Huntington’s: A Disease Characterised by an Altered Brain
31
A Star is Born By Adam Smith 8H
I
s our Universe infinite? We do not know, but what we do know
have been scratching about for the last 200 thousand years,
for sure is that it has been changing all the time during its 13.7
1/25000th of the Sun’s life [4][5].
billion years’ life [1]. It is at least 93 billion light years across,
A star starts out life in a nebula, a massive cloud of hydrogen
and there are at least 1021 stars in the observable universe, as a
gas. This cloud is formed by the death of a star and like an old
small portion of which can be seen in the image from the Hubble
tree falling in the forest, gives life to hundreds of new stars [6][7].
space telescope extreme deep field image, Figure 1 [2][3].
As acorns are shaken from their parent trees by autumnal gales,
Our Sun, one of the most average, yet most beautiful stars, will
it is thought that the shock waves from distant supernovae start
live for five billion years more: it is now middle-aged. Humans
the seeding process which causes hydrogen gas to coalesce. This ball spins like a young girl dancing and as it does, it grows a skirt of gas and dust spinning with it. In this accretion disc, clumps of gas and dust collide forming planetesimals. The star is now called a proto-star and it gathers gas and dust around it [8]. This protostar, a T Tauri star, begins to shrink from several astronomical units (distance from the Earth to the Sun) in diameter to main sequence size[9]. Main Sequence Stars follow a rule, small stars live longer and glow red whilst larger stars live short violent lives and burn bright blue (Figures 2 and 3). It then ignites into nuclear fusion. Nuclear fusion is where nuclei fuse
Figure 1 Image of the Extreme Deep Field
32
A Star is Born
and turn into heavier, more complex elements. The first step in fusion is from hydrogen to helium.
As fusion starts, the star blasts out a gust of solar wind like a hurricane over the Caribbean. The gust blows away the unbound gas and dust in its protoplanetary disk leaving a new-born, violent, unruly set of planets [10].
Figure 2 The evolution of stars from nebula to death. Credit - NASA
The star was born in a cluster of its brethren but now it abandons this brotherhood, to make its own way through the Universe.
Figure 3 Stellar Evolution.
It has a violent youth, as it frantically continues to fuse its
in the Universe, and enough power to outshine an entire galaxy.
hydrogen fuel into helium, releasing
energy according to
It forms a huge nebula, shearing the crusts of the surviving
Einstein’s equation (E=mc2); completely ignoring the fact that
planets, and leaving molten cores orbiting a black hole. The
its planets, sunk in the rubber sheet of space-time, are playing
shockwave from the supernova emanates, hitting a second
pinball with each other, throwing out rogue planets to find their
nebula, and starts the process all over again. Finally, deep in the
own way in the Universe [11].
star, gravity gets its way, ripping a hole in space time, a black
The star, now with a settled mass and the winners of the cosmic
hole, something so powerful not even the racehorse of the
pinball match asserted, flies through space, having occasional
Universe, light, can escape.
close shaves with other stars, their Oort clouds (containing comets that occasionally light up our skies like a silver knife through butter) brushing by [12]. Now the star, following a short and violent youth, is aging. After feasting on hydrogen fuel it is in trouble, unable to sustain itself. Its huge mass has become its literal downfall. But this mass is also its saviour, permitting the star to fuse helium as the core temperature and pressure increase. It comes back, as a bloated red giant, creating carbon and oxygen, the building blocks of life [13]. As the star runs out of helium, it frantically smashes carbon together, and fuses it into silicon. The core of the star resembles a swollen onion the remainders of what it used to be layering a silicon core [14]. Finally, the star is out of carbon fuel. In a last ditch attempt to stop gravity taking over, it crushes silicon into iron, and expands greatly, tearing up its planets, leaving only the outer ones surviving. As it runs out of silicon, it tries to fuse iron into further elements but as iron does not give out energy when fused, it begins its death throes [14]. Gravity finally wrenches power from fusion and the star implodes. But inside, deep in its iron core, something amazing is happening. Protons, as they are naturally introverts, push away other protons. This aversion between protons stops gravity’s onslaught for an instant but this attempt is futile. Protons fuse with electrons and create neutrons that we can think of as hard balls, cannot be compressed when touching [15]. Yet, nothing can halt gravity’s hunger for destruction. Then, in a violent birth cry, the star explodes, with enough force to form every element
Figure 4 Computer artwork of a red giant, with a dead planet passing
A star is born, formed from the flesh of the Universe; a star dies, returned to the flesh of the Universe, (Figure 4). It razed its planets, only to raise them up again. Its legacy, transmuted from Hydrogen, a whole raft of new elements, from Helium to Carbon to Silicon to Iron. These will build civilizations, and they will destroy civilizations. The star has disappeared, but soon its history will be told by travellers from all over the Universe, the story of change
A Star is Born
33
Can we Envisage a Future where Viruses Replace Antibiotics? By Daniel Goldstone L6S1
T
he global death rate from antibiotic resistance is about
started in 1915, before the first antibiotic had even been isolated.
one per minute[1]. This is not the result of a novel complex
As with many other scientific breakthroughs, bacteriophages
disease, but due to the mishandling of a cure that was
had been discovered by Frederick Twort by accident [4]. The
meant to end all bacterial infections which result in fatality. We
observation that ‘glassy’, transparent patches of dead bacteria
are now approaching a public health crisis where some bacteria
were present in petri dishes led to the hypothesis that a virus
can be resistant to almost all known antibiotics in use at present.
was the cause of this, but the proof was difficult to establish.
For example the treatment of drug-resistant Mycobacterium
In 1917 Felix d’Herelle independently proved the existence of
Tuberculosis can only be attempted by drugs with serious side
bacteriophages and over the last 100 years phages have been
effects, such as kidney or liver damage [2]. The first warnings of
found in every environment on Earth [5]. It is believed that there
antimicrobial resitance to drugs predates Alexander Fleming’s
is at least one type of phage for every strain of bacteria. They
discovery of Pennicillin by four years and it is certainly not a new
were initially introduced in India to treat cholera, after they could
problem for the scientific community[3].
be isolated from patients’ stools and purified until they became
Yet despite the knowledge of this looming threat of doom, for
safe to use. However, bacteriophages were subsequently
over 90 years, there has been little effort to curb the increase
forgotten by modern medicine as antibiotics became cheaper
in resistance. Science now needs to discover rapidly a solution.
and more successful at a much faster rate.
Ironically, an answer to the problem of antibiotic resistance 34
Can we Envisage a Future where Viruses Replace Antibiotics?
Figure 1 The Viral Life Cycle
As bacteriophages are a type of virus, they cannot perform
membrane, produce toxins and eventually destroy the cell. In
life processes or reproduce by themselves. Studies of phages
addition, many bacteria produce a biofilm which aid protection
using electron microscopy in 1940 revealed that they needed
from antibiotics and enhance resistance[8]. However, the biofilm
to infect a host cell, usually bacteria, in order to reproduce
can easily be broken down, in many cases, by phage enzymes
successfully[6]. The bacteria provide nutrients and organelles,
rendering it ineffecive in protection.
in order, to facilitate the replication of the virus many times.
Although phage therapy may seem a perfect solution for the
However, this resuts in the destruction of the host cell. Proteins
increasing threat of antibiotic resistance, there are a number
on the surface of bacteria enable the phage to recognise the
of significant challenges that have proved difficult to overcome
correct strain. Once contact is made between the phage and
over the past 100 years. This has meant that at present phages
the bacterium the loop of viral DNA is injected into the bacteial
are not widely used globally because the extraction and
cell, in order for replication to proceed. Once copied, the DNA
subsequent injection of samples that are considered safe is a
is packaged into a new membrane and the toxins produced by
highly time consuming and costly process. If the phage is not
the virus cause the bacterial cell membrane to release the new
successfully separated from the dead bacteria, the sample used
phage particles and the cycle then repeats. (Figure 1 A-E), [11]
for treatment will not be safe and the patient could develop
Phages offer a greater advantage over antibiotics due to the
sepsis, which could result in fatality.
significantly different method by which they destroy bacteria.
However, with the advances in scientific technology in recent
Antibiotics are substances that kill bacteria by disrupting their
years, the safety concerns have been overcome to some degree.
cell processes in a number of different ways. For example the
Indeed the European Union recently invested in a treatment
most prominent antibiotic, penicillin, prevents bacteria from
called Phagoburn which uses phages to prevent skin infections
building a cell wall (Beta-Lactam) [7]. Bacteria are unable to
in burn victims [9]. There is also further hope for the approval of
surive without a cell wall, when the pressure inside the cell wall
clinical trials in the treatment of tuberculosis, MRSA, and many
becomes too high and cause the membrance to burst. Human
other infections caused by antibioitc resistant bacteria.
cells do not have a cell wall so they remain unnafected. Other antibiotics work by interfering with ribosomes(macrolides) and preventing protein synthesis in cells. Human ribosomes are different from bacterial ribosomes and remain unnafected by the antibiotic. Phages can be used to treat antibiotic resistant bacteria as it is more difficult for bacteria to develop resistance against them than traditional antibiotics. Instead of inhibiting one specific cellular process phages can attack the bacterial cell wall and
The use of phages to kill bacteria also further reduces antibiotic resistance which could lead to a future of phages and antibiotics being used side by side to kill all bacteria and prevent large scale resistance to both agents [10]. There could be a time in the future when phages replace antibiotics as the first line of defense against infection, but while research progresses slowly we have to be increasingly careful of unlimited use of antibiotics
Can we Envisage a Future where Viruses Replace Antibiotics?
35
How has the Universe Changed Since the Big Bang? By Veylan Sebastian 11J2
T
he universe is an immensely dynamic entity, where
The universe, starting off as this singularity, was unbound from
change occurs constantly, throughout. This article focuses
the fabric of space- time. When the universe was around 10-37
on what these changes are, why they happen, and what
of a second years old, the initial inflation of the universe began,
predictions could be made for the future.
where matter was travelling faster than the speed of light. Here
Our Universe is infinite, with an estimated 200 billion galaxies,
we can see how change has happened at a vast scale even
and about 100 billion stars in the Milky Way galaxy alone.
when the universe was just born, and how volatile it was at the
However, the universe was not always this large, 13.8 Billion
beginning. After the singularity initially exploded, what was
years ago the universe was just a single point known as a
created was a soup of quark and gluon plasma, which only exists
singularity, it was a point of infinite gravity and density [1][2][3].
where there is an extremely high temperature or density[4]. Succeeding this, at 10-6 seconds, particle energies dropped due to cooling and quarks and gluons combined to form protons and neutrons (baryons). Due to the ongoing expansion of the universe, its characteristic temperature was decreasing, which led to particle energies decreasing and the process of annihilation occurring. Annihilation is where the baryons (protons and neutrons) collide with antibaryons (antiprotons and antineutrinos) to release energy. However, the radiation formed is unable to re-combine to form new baryon-antibaryon pairs. These collisions resulted in a decrease in baryons overall, but with a concomitant increase
Figure 1 Metric expansion of space
36
How has the Universe Changed Since the Big Bang?
in photons.
At a temperature of around 109K, a few minutes into the expansion, most of the protons present were un-combined (hydrogen nuclei). However, some combined with neutrons to form Deuterium and Helium nuclei, a process known as nucleosynthesis. However, atoms were not created, as the universe was still too hot for electrons and protons bound with neutrons (nuclei) to be attracted to each other, so the nuclei of the elements were created, meaning that it was in a form of plasma. There were no atoms formed at this time, and this lasted for around 380,000 years [4]. Only after this was the universe cool enough for electrons to combine with nuclei, to form atoms. This was the first time that atoms were created, and this caused radiation to split away from matter, as it was emitted. This radiation continued travelling through space without any obstacle, resulting in the cosmic microwave background radiation, abbreviated as CMB radiation. This is evidence of how our universe changed so much in such a small amount of time relative to how old the universe is now, and this cosmic background radiation is still here today and is how we know how the universe looked 13.8 billion years ago [1]. Only 400 million years after the Big Bang, did the universe become bright, and emerge from the cosmic dark ages where no stars or galaxies existed. The gravitational pull of small fluctuations in density of matter resulted in the formation of gas clouds, which became nebulae, causing the formation of stars and galaxies [5]. The universe was still expanding, but there was a change in the rate of expansion. The cause of the universe’s acceleration is thought to be due to dark energy; as it acts in the
Figure 2 Big Crunch Theory
The Big Crunch is the fate of the universe if the density of the universe is larger than the critical density as the universe would stop expanding, and would contract and become hotter, shrinking back down into the initial singularity due to gravity [7]. The Big Rip is where, if the density of dark energy grows, and would tear the universe apart, as the dark energy would drive everything apart, including atoms themselves. This happens if dark energy is denser than the object in question as it allows the space within particles to expand, forcing their constituents apart [7].
opposite direction of gravity, exerting a repulsive pressure on space itself. This causes the universe to expand and the edges of the universe move further apart as its fabric stretches like the surface of a balloon. There are galaxies in the universe where we can’t reach because they have dwindled from Earth quicker than light released from us will ever be capable to travel. On average, 20,000 stars become unreachable every year [6]. The universe will experience a great change at its ultimate fate as well. There are 3 main theories about the ‘end’ of the universe, called the Big Freeze, Big Crunch and the Big Rip [7]. All of these depend on the density of the universe and dark energy. The Big Freeze is when the entropy of the universe increases until it reaches a maximum value and heat in the system will be distributed evenly. This would result in no usable energy being available and mechanical motion within the universe ceasing. As gases present would be spread evenly no new stars could form and there would be little energy left in the universe [7].
Figure 3 Artists representation of Big Rip
In conclusion, the universe is constantly changing, and has been since its inception. There is a chance that this change may cease in the Big Freeze and Big Rip, which would be fascinating as this would be the first time the universe has stopped changing.
How has the Universe Changed Since the Big Bang?
37
The Emergence of Lithium as a Possible Solution to the Global Energy Demand By Phalgun Deevanapalli 8R2
T
38
he burning of fossil fuels releases greenhouse gases
to have been created during the first few minutes of the Big
to the atmosphere, which subsequently traps the heat
Bang [1]. It has been known since 1817, when a sample of the
energy released from the Earth. The long-term heating
element was purified from a mineral found in the UtĂś Mine, in
of the Earth’s climate system, known more commonly as Global
the Stockholm archipelago [1]
warming, is thought to be largely due to human activities,
The Global production of lithium in 2014 was 36,000 metric tons
and observed since the industrial revolution. In addition, the
[2]. So where does lithium come from? Most of the lithium on
increasing number of vehicles powered by hydrocarbon fuels
Earth is in South America, specifically in the Andes Mountains
has also led to exhaust fumes causing significant environmental
that run through Chile, Argentina and Bolivia [2]. There are
damage due to the harmful pollutants that are released to the
also deposits in China and the USA, some of which are mined
atmosphere.
traditionally from the rock.
Despite the Global reliance of this form of energy, fossil fuels are
If hydrocarbon fossil fuels are to be replaced by alternate
a finite resource. As governments and consumers demand new
sources of energy, the production of vehicles which could be
fuels with greater efficiency, new sources of renewable energies
powered by electricity producing batteries which can store
are coming into play. The latest in this technology is lithium-ion
large amounts of energy is vital. The two types of rechargeable
powered batteries, designed to be used in both electric and
batteries developed prior to the lithium batteries were the
hybrid cars of the future. Lithium-ion batteries are lighter than
heavy lead battery that was invented in 1859 and the nickel-
currently used batteries and they also hold charge a lot longer.
cadmium battery that was developed in the first half of the
Lithium, the third element in the Periodic Table, is thought
20th century [1].
The Emergence of Lithium as a Possible Solution
Figure 1 World’s Lithium resources
Whilst the Nickel-based batteries operate at voltages of 1.2
the harmful effects [3]. The Lithium-ion battery has enabled
volts, the lithium rechargeable batteries have higher voltages,
the development of cleaner energy technologies and electric
typically around 3.7 volts. In addition, they can store more
vehicles resulting in reduced emissions of greenhouse gases
energy especially in consideration of their size and weight [3].
compared to hazardous methods of fracking to obtain oil and
Lithium-ion batteries also have a lower self-discharge rate (0.35
gas, which greatly damage the environment and ecosystems.
– 2.5% per month) compared to Nickel -Cadmium batteries
Lithium-ion batteries are a great asset for the world to benefit
which lose their charge at a rate of around 10% per month [3].
from, as they have enabled the development of laptop
This means that once charged the lithium batteries will retain
computers, mobile phones, electric vehicles and the storage of
their charge for longer periods of time than other types of
energy generated by solar and wind power [1].
rechargeable batteries.
To a large extent, these developments have been made possible by the lithium-ion battery. This type of battery has revolutionised the energy storage technology and enabled the mobile phone revolution. Through its significant potential, and high energy density and capacity, this type of battery has already contributed to improving and changing our lives; and arguably will continue to do so in years to come. However, battery development is very daunting and challenging in general, and perhaps particularly so when it comes to lithium-based cells.
Figure 2 Charge and discharge of a battery
Even if they are not installed in a device, Lithium-ion batteries retain most of their charge after months of storage [3]. Lithium-ion batteries could create a world free of fossil fuels possible, as they can be used for powering electric cars and for storing energy from renewable sources. The need for new renewable sources of energy has escalated to almost a state of urgency as the drastic effects of global warming
Figure 3 A Lithium Ion battery in a phone
become increasingly significant.
The Nobel Prize for Chemistry in 2019 rewards the development
Although the production of lithium-ion batteries has an impact
of the lithium-ion battery. That itself is a testimony that Li-ion
on Global warming, the benefits to the environment outweigh
is here to stay and would be further enhanced in coming years.
The Emergence of Lithium as a Possible Solution
39
How Logistic Maps Changed the Way We Think By Rishi Virani L6J1
C
haos is defined as the property of a complex system
It considers discrete time steps, mapping the population
whose behaviour is so unpredictable that it appears
value at any time step to its value at the next time step [2][3].
disordered and completely random [1]. However, this
Mathematically it can be expressed as:
could not be further from the truth. Within the apparent randomness of these chaotic complex systems, there are patterns, interconnectedness, constant feedback loops and repetition, suggesting that these systems are deterministic. This means that there is no randomness involved in the model, producing the same output from a given input [1]. How could such a complex system show some regularity? The popularisation of logistic maps was the first step taken in changing our understanding of deterministic chaos. What is a logistic map? A logistic map is one of the simplest examples of non-linear dynamical equations that result in complex, chaotic behaviour.
40
How Logistic Maps Changed the Way We Think
Xn+1 =λxn(1−xn) [2][3] Where xn represents a value between 0 and 1 that denotes the ratio of the existing population to the maximum possible carrying capacity and λ denotes the growth rate of any population which follows a mating season, such as rabbits or foxes, taking a value between 0 and 4. We cannot consider any values of λ greater than 4 since this would lead to negative population values or populations greater than the maximum carrying capacity, which are not possible. In effect, this equation shows that the population at any given time is the function of the growth rate parameter and the previous time step’s population level. [2][3]
Figure 1 Diagram to show the bifurcation diagram produced by a logistic map
What is the effect of changing the population growth parameter? One of the most interesting features of logistic maps are the population values they tend towards as the value of λ changes. To investigate this, we can plot the attractors of the logistic map, which is the value, or set of values, that the map tends towards over time, as a function of the growth rate parameter λ. This is known as a bifurcation diagram, as shown in Figure 1 [4] This diagram can be thought of as 1000 discrete vertical lines, each one corresponding to one of the 1000 values for λ between 0 and 4.0. For each of these vertical slices (or values of λ), the equilibrium population is then plotted, known as the attractor as discussed before. [3]
Figure 2 A graph to show how the population changes over time for different growth rates [3]
exact stable population level. By considering each of the vertical
At first glance, this diagram looks complicated and almost
slices above each growth rate parameter, we can see that there
‘chaotic’ with the attractors exhibiting different behaviours as
is only one population level present. The higher the value of λ,
the growth rate parameter changes (λ), particularly at values of λ greater than 3 in which the diagram seems to no longer follow a pattern. However, this could not be further from the truth.
the higher the value of the equilibrium population. [5] However, above values of 3.0, the diagram exhibits a much more interesting behaviour, whereby the population does not
When the value of λ is below 1.0, the system has a fixed-point
appear to equilibrate around a fixed attractor value, but rather
attractor (equilibrium value) at population level 0, resulting in
oscillate between 2 different values. This means that applying
the population to tend towards extinction (Figure 2). [5]
the logistic equation to one of the values will yield the other. As
The bifurcation diagram also shows that values of λ between
a result, the bifurcation diagram forks into two discrete paths,
1.0 and 3.0 always cause the system to equilibrate towards an
never settling on a single value. [3]
How Logistic Maps Changed the Way We Think
41
As the value of λ continues to increase, these forks spread
the temperatures detected produced a very interesting pattern,
apart, eventually splitting apart again, causing the population
similar to that of the logistic function. At low temperature
to oscillate between 4 different population values rather than
gradients, there was a single periodic spike in the temperature,
2 [3]. Since the number of population values the logistic map
similar to the logistic function which equilibrates to a single
oscillate between (periods) has doubled, this is known as
value at low values of λ. However, as the temperature gradient
period doubling bifurcation [3]. However, as λ increases further,
was increased, the spikes in temperature cycled between 2
there are more period doubling bifurcations, occurring faster
values. As the temperature gradient continued to increase, the
and faster, leading to cycles of 8, 16, 32 and 64 and eventually
number of temperature spikes continually doubled, eventually
a period of infinity at λ = 3.57 [3]. Beyond this value, the map is
reaching a pattern of temperatures which seemed random
driven to chaos, in which the function is capable of landing on
and unpredictable. It was proposed that the period doubling
any population value and never repeating itself or equilibrating
bifurcations produced by the logistic function when increasing
into a steady behaviour [3]. It is this that provided evidence for
the value of λ could be used to explain these patterns,
deterministic chaos.
confirming the logistic map theory [6][8].
What are the applications of logistic maps?
The logistic function also shows parallels to medicine. In one
Logistic maps have been crucial in mathematical biology
study, rabbits were given a drug that sent their hearts into
to model animal populations. They show that the erratic
fibrillation, in which the heart shows irregular behaviour.
fluctuations in animal populations are not due to sampling
However, on the path to fibrillation, their heartbeats showed
errors or the difficulties of maintaining a controlled environment,
behaviours similar to that of the bifurcation diagram, where
which many biologists had conjectured, but rather the
the heartbeat exhibited period doubling bifurcations into
deterministic nature of the logistic map. This can be explained
chaos [9]. This meant their heartbeat was periodic, starting
by the sensitivity of the logistic map to initial conditions – the
with 2 heartbeats together, then 4 then 8 and so on. It was the
chaotic region of the map means that initial conditions that are
chaotic behaviour of the heartbeats that allowed scientists
arbitrarily close will diverge widely after multiple iterations,
to investigate when to apply electrical shocks to return to a
making long term prediction almost impossible [6][7].
regular heartbeat [6][9].
It is this quality of unpredictability and apparent randomness
Logistic maps have brought about a lot of change in the world
which led to logistic map equation to be used as one of the first
of science, mainly through providing one of the first pieces of
pseudo-random number generators [6].
evidence for aperiodic deterministic chaos. It was this idea that
This equation can also be applied to fluid dynamics. This
helped provide many explanations for many natural phenomena
was observed when a temperature gradient was applied to a
which seemed almost inexplicable. Used as a basis to describe
small rectangular box containing mercury in order to induce a
such complex behaviours, it is as though it could be considered
convection current. In order to monitor the temperature of the
the mother of deterministic chaos.
fluid, a thermometer was placed at the top of the box. However,
Figure 3 Diagram to demonstrate the period doubling bifurcations in fluid dynamical systems.
42
How Logistic Maps Changed the Way We Think
How Hypersonic Weapons Will Transform Modern Warfare By Jitong Zhou 11H2
M
odern warfare is characterised by the balance between
to build a rocket-boosted bomber which would glide along the
defence and offense. The introduction of hypersonic
Earth’s upper atmosphere, to attack New York from Germany,
weapons, travelling at least five times the speed of
was based on the accidental discovery by German soldiers that
sound, will open-up a new era of missile and nuclear warfare.
their bombs seemed to glide over a longer distance when they
With the current limitations of anti-missile technologies, these
were dropped at a higher altitude [3]
hypersonic cruise missiles and hypersonic glide vehicles will
However, like many missiles designed during the Cold War,
result in the offense side soon over whelming, the defence.
using this same idea, they were never tested but only existed in
The idea of using hypersonic weapons was first proposed by
theory to extend range and accuracy [4].
the German scientist Eugen Sanger in 1941[1][2]. His proposal
How Hypersonic Weapons Will Transform Modern Warfare
43
Since the turn of the century development of hypersonic
This makes HGVs much harder to detect let alone intercept
missiles has been restarted by superpower nations like the U.S.
using existing missile defence solutions, because they glide
and Russia. This is because while ballistic missiles are fast for
at much lower altitudes of 35 km compared to ICBMs (which
most of their flight they follow a sub-orbital parabolic trajectory
are generally propelled to altitudes of 1000 km) and they are
which can be calculated by ground radars and satellites.
able to manoeuvre through the entire boost-glide and terminal
Factors such weight, velocity and angle of the warhead bus at
phase [11] [12]. Their lower altitude and the Earth’s curvature
the end of the boost phase can be accurately determined [5].
make it much harder for radar waves to detect them, and even if
Cruise missiles, despite being manoeuvrable during their flight,
they are seen by satellites or ground-based radars, current anti-
have relatively low speeds [6]. Hypersonic boost-glide vehicles,
missile technologies are incapable of intercepting them during
such as the Russian Avangard missiles are 20 -27 times faster
their boost-glide phase [8].
than the speed of sound and are able to manoeuvre during their
Conventional ICBMs follow a predetermined trajectory in space
midcourse and terminal phase [7].
for most of their flight guided primarily by their weight during
Hypersonic boost-glide vehicles, or HGVs, are launched from the
the midcourse and terminal phase. This means that as soon as
ground or through submarines and they are propelled to space
the missile’s launch is detected by its infrared signature by a
using the same rocket boosters in traditional intercontinental
satellite, nearby interceptors can destroy the entire missile
ballistic missiles (ICBMs) [8]. However, rather than continuing
including all of the warheads and decoys [13]. Even if not
to fly along a sub-orbital orbit they descend to the Earth’s upper
destroyed during the boost phase, systems like the Israeli Arrow
atmosphere and employ aerodynamic lift to glide or ‘skip’ along
3 system can intercept warheads during midcourse because
the Earth’s atmosphere using scramjet engines to propel them
it follows a predetermined trajectory that can be calculated
to hypersonic speeds. Scramjet engines significantly reduce
on the ground [14]. If the warhead still manages to escape,
the missile’s weight because as soon as the HGV is travelling
decluttering of the real warhead and fake decoys occurs due
at supersonic speeds, it is able to take in oxygen from the air to
to their different masses, which result in deceleration rates
react with liquid hydrogen that it carries. Rather than carrying
that are distinct as they re-enter the atmosphere. This means
liquid oxygen like traditional ramjet engines which make up
that the real warhead can be easily identified and destroyed by
70% of the fuel used in ramjets [9] [10].
short-range interceptors [13].
Figure 1 Comparison of ballistic and boost-glide.
44
How Hypersonic Weapons Will Transform Modern Warfare
Figure 2 Interception of an ICBM during midcourse.
Hypersonic boost-glide vehicles crucially are able to constantly
Directed-energy weapons, like lasers, would be mounted on
manoeuvre during the majority of their flight, except during the
unmanned airborne platforms to target HGVs while they are
boost phase because they are launched using the same rocket
in the boost phase, but these are still under development
boosters as conventional ICBMs. This means that even if their
and can be limited by their range. In addition, flying deep into
infrared signature is detected, their exact target will not be
enemy territory would significantly increase the chances of the
known because they can constantly change trajectory during
airborne platform being shot down by surface-to-air missiles.
flight and even change target midcourse [15]. This makes the
Similarly, space-based interceptors are still being studied
entire area within the hypersonic missile’s range a possible
but they may lead to the weaponisation of space and various
target for attack and it means that the HGV is able to actively
technologies are capable of destroying satellites in space using
avoid layered missile defence systems and ground-based radar
missiles [13].
coverage. The super-heated plasma around a HGV means that
All in all, hypersonic weapons present an opportunity for
radio waves from ground based-radars may be absorbed, and
offense to completely overwhelm defence capabilities. But the
tracking the missile through its flight is made more difficult
deployment of missiles that can travel at hypersonic speeds
because current infrared detection systems using satellites in
and strike its target in under ten minutes paints a threatening
space are at present unable to continuously track an object
picture of the ‘nuclear button’ being handed directly to
like HGVs which will manoeuvre continuously throughout their
military chiefs; who would indiscriminately launch aggressive
flight [16].
counterattacks as soon as a hypersonic missile is detected,
Among the options discussed for intercepting HGVs include
because there is no time to interpret the missile’s final target.
directed-energy weapons and space-based interceptors [13].
Figure 3 An HGV during its boost-glide phase.
How Hypersonic Weapons Will Transform Modern Warfare
45
How did Concorde Change Modern Aviation? By Ojas Sharma 8S2
C
an you imagine an aircraft taking less than three hours
Concorde burst into flames moments after take-off, killing 113
to fly from New York to London? It is very hard to imagine
people and it never recovered afterwards [6]. Concorde made its
that a commercial aircraft could fly at twice the speed
last flight on the 24th of October 2003 [7].
of sound 40 years ago [1]. However, on the 2nd March 1969
Concorde used revolutionary technology. One example of this
Concorde managed the impossible, and it was truly way ahead
is the delta-wing design. It is very different from many other
of its time!
commercial aircraft. The delta-wing design helped in many
The world’s first commercial aircraft began service in 1914 [2]. It
ways; such as reduce drag by being thin and provided sufficient
flew at an average speed of 89 km/h or 54 mph and was called
lift for take-off and landing at subsonic speeds. Also by providing
the ‘flying boat’. On the other hand, the Airbus A380 flies at
stability in-flight there was no need for horizontal tail-wings [8].
roughly 903 km/h or 561 mph [3]. Although that might sound
The delta-wing design is not the only design feature that helped
impressive Concorde was even faster [1]; it flew at 2,160 km/h
Concorde reach supersonic speeds. Even the fuselage helped
or 1350 mph and was the fastest commercial airliner, with a
reach supersonic speeds [9]. It was narrower than a normal
maximum speed which was twice the speed of sound.
jumbo-jet, helping to reduce drag. There was also a moveable
Concorde was operated by Air France and BOAC (British Overseas Airways Corporation) [4] and first flew in 1976 [5]. It was the first, and only to this date, commercial supersonic jet, and it cut transatlantic flight times by half. However, disaster struck the business on the 25th July 2000, when an Air France
46
How did Concorde Change Modern Aviation?
nose at the front of the aircraft. The nose had to be pointed and straight in order to penetrate the air most efficiently. However, during take-off and landing, in order to prevent the visibility of the runway being obstructed, the nose could also be lowered [9]. These are a few examples of the technology that enabled Concorde to reach the high speeds it did.
Figure 1 Concorde’s Cockpit. There would be 3 people operating the aircraft, 2 Pilots and 1 Flight Engineer.
The change made by Concorde to modern commercial aviation
the flight would also cost less than it did on Concorde [12].
is minimal, if not none. Nonetheless, it revolutionised the
Without the Concorde, the technological advances would not
way that military supersonic aircraft worked. It showed that
have been made and mass supersonic travel will not be a thing
supersonic travel was possible and could be achieved easily
in the future. It is already planned for a no-sonic-boom private
and with advances in computer technology.
jet to take to the skies in 2023 [12]. This is a significant advance
Looking into the future, the company Boom Supersonic has
for technology as we will now see a ‘non-booming sonic-boom’
been designing a 55-seater modern, supersonic jet that will
making it possible to fly over countries at supersonic speeds.
fly faster than Concorde [10]. Looking to fly its test flight in
Overall, the Concorde has shaped the modern fighter-jet,
the mid-2020s [11], Boom Supersonic already has 76 pre-
but has made its way into business and has encouraged a
orders for aircraft, from companies such as Virgin Atlantic.
comeback of commercial supersonic flight. Concorde made a
Without Concorde, commercial supersonic aircraft would not
lasting impact on all aspects of aviation. The change may not
be attempted, and it would be hard to advance further. Boom
yet be visible, but within the next decade, it will reveal itself in
Supersonic says that their aircraft will cost less than the
the industry.
Concorde due to advances in technology and that a ticket on
Figure 2 A British Airways Concorde plane leaving London Heathrow airport in the mid-1990s.
How did Concorde Change Modern Aviation?
47
Are Humans still Evolving? By Theo Silverbeck L6S2
T
o answer this question, we must first define evolution as its description often varies and the many definitions are often equivocated, creating confusion on the topic.
However, the relevant definition, which I will be using, is “the change in gene frequencies over time, meaning that over generations there will be changes in the gene pool”[1]. At first thought it seemed unlikely that humans have become exempt from the governing forces of biological evolution which have shaped the history of life for 3.5 billion years [2]. I was
in agreement with Dr Russel Powell who described this as an “extraordinary claim”[3]. The thought behind this claim is that our species’ technological capacities override the effects of natural selection. Due to human methods, superiority and fitness is no longer rewarded with reproductive success so the traditional evolutionary process of natural selection seems of negligible impact [4]. For instance, Michael Balter (2005) says that “the goal of much of modern medicine and culture is effectively to stop evolution”, meaning that the fitness differentials which exist between competing genetic variants are now insulated by modern medicine, which removes the genetic advantages some humans hold to survive and avoid health conditions which detriment fecundity [5]. The view that “natural selection has almost become irrelevant” seems likely but this argument conflates natural selection with evolution itself [6]. Natural selection is not the only method for evolution so even if the selection pressure is removed, this does not necessarily entail that evolution is over.
48
Are Humans still Evolving?
Figure 1 Niche construction
The causes for the hypothesized reduction of natural selection taking place are twofold. Firstly, through phenotypic plasticity, humans can ‘adapt’ (defined as the process of improving the ‘fit’ between an organism and its environment), to their environment without altering their genetic code [7]. Due to the homo sapiens species being globally spread over a vast array of climates and conditions, we have evolved phenotypic plasticity as a way of altering our phenotype (displayed characteristics) without any changes in our genotype (genetic constitution). This is extremely advantageous as it allows organisms to respond in intra-generational time to ecological changes that are too rapid or vast for natural selection to compensate for (such as those caused by climate change or migration), allowing them to survive changes which they otherwise would not be able to, known as ‘plastic rescue’. An example of phenotypic plasticity is that humans exposed to famine in the womb exhibit higher
rates of obesity and heart disease in adulthood than siblings conceived under better conditions due to expressing different phenotypes to counter this selection pressure despite having similar genotypes [8]. This phenotypic plasticity means that when an environmental condition changes, it does not act as a selection pressure for humans as our phenotypic plasticity means we can alter our characteristics to suit the reformed
Figure 3 More examples of genetic evolution as a result of cultural evolution, Salzano 2012 [13]
environment without evolution, an inheritable change in
pressure is of agricultural practices creating more stagnant
genetic make-up, taking place. Therefore, natural selection will
water, a breeding ground for insects, allowing insect vectors
not take place.
(such as Anopheles mosquitoes) to increase in population and
The second way that natural selection is buffered is by niche construction, defined by Odling-Smee (2003) as the active modification of an organism’s environment [9].This is not unique to modern day humans, all organisms determine their environment to a certain degree; however, “the technological revolutions of the 20th century have allowed for the anthropogenic alteration of global ecosystems at a
spread diseases (such as malaria) more so than in prior niches. This has led to genotypes for the resistance of certain diseases to be favoured and therefore natural selection to take place [12]. As diseases evolve to overcome our resistance, humans are predicted to continue to evolve to become resistant once again and the ongoing ‘evolutionary arms race’ between human populations and parasites will only continue.
magnitude, rate and intensity that dwarfs the entire history
Phenotypic plasticity does not always buffer evolution.
of human impact combined” [10]. Once again, this means that
Although rapid changes in phenotypes are made possible by
subtle environmental changes which originally would have
this plasticity there is convincing evidence that this, once again,
had catastrophic effects to our species are hardly detrimental,
augments longer term changes in genotypes over generations.
being overcome by technological solutions. Obvious examples
“Plasticity is conducive to evolvability insofar as it allows for
of such niche construction are all around us – buildings with
an initial period of tolerance to novel episodes of phenotypic
temperature controlling methods or agricultural production
selection, which may then be followed by gene-based
practices (such as using chemical fertilisers).
adaptation to the new selective regime” [3]. After a “period of tolerance”, a gene-based adaptation occurs, meaning that the environmental stimulus responsible for the phenotype’s change is no longer causally important. Evolution allows the trait to stay regardless of whether it is needed, allowing humans to evolve, to have more extreme phenotypes ready to be expressed through plasticity if needed. This evolution helps to further protect the human species from extinction due to environmental changes. Furthermore, if the selection pressures are indeed relaxed then
Figure 2 Lactose introduced through agriculture
intra-specific genetic variation will occur, causing genetic drift
However, these forces do not always buffer but sometimes
and then eventually evolution due to an advantageous gene
augment evolution. With cultural evolution creating niche
being expressed and favoured. On the other hand, if the theory
environments, gene-culture coevolution takes place. An
of the selection pressures being weakened is fallacious then
example of this is outlined by Powell and shows how the niche-
evolution will continue as well. Therefore, as Powell (2012)
construction behaviour of domestication of cows leads to an
stated, there is an “evolutionary catch-22” and it will continue
increase in the ecological resource of milk, generating selection
to occur regardless of selection.
pressures of its own – the pressure for genotypes for the ability
To conclude, the buffers
of digesting and making use of the ecological resource of milk
of phenotypic plasticity
[3]. This lead to the spread of the lactose tolerance gene (the
and niche construction
LCT gene) which is evident by more than 65% of people East
may act to slow down
Asian descent being lactose intolerant but only ~5% of people
human evolution but
of Northern European descent having this intolerance due to
we are undoubtedly still
evolution [11]. Lactose was mostly introduced into European
evolving as a species
farming so the gene-culture coevolution took place to introduce
due
genes for lactose digestion. However, this was not the case in
coevolution and due to
East Asia, meaning that there is a high prevalence of lactose
genetic drift occurring in
intolerance, people missing the gene for lactose digestion.
a less selective modern-
Another example of our niche construction forming a selection
day environment.
to
gene-culture
Figure 4 Medical drugs
Are Humans still Evolving?
49
Scientific Research Work Experience Report By Nirvan Marathe L6C2 Name of Organisation: St. Thomas’ Hospital (affiliated with King’s College, London)
which a probe is set up so it stays in place. Then a band with a pump, containing vaso-active substances, is attached to the patient’s arm; in order to cause the dilatation of the brachial arterioles. Comparisons were also made to see how the
O
n the first morning, we had a lecture about safety in laboratories and were briefed on several rules and procedures. Subsequently there was a tour of the
facilities and we were provided with our own lab coats and goggles. In an office space shown to us, we completed the legal
dilatation changes during the systole and diastole of the atria and ventricles of the heart. Probe readings were observed on a chart. Ultrasound was used to find the arteries within muscle tissues and then blood flow was monitored. We were clearly able to observe the changes in artery diameter in relation to heartbeat and dilatation.
Figure 1 Flow mediated dilatation
paperwork which permitted us to participate in the placement. For the second half of the day, we observed flow mediated dilatation [Figure 1] being carried out by Dr Boguslavskyi on a volunteer patient for around two hours. Flow mediated dilatation is a procedure used to determine if patients are prediabetic. It involves a gel being applied to a patient’s skin, on
50
Scientific Research Work Experience Report
The following day, Tuesday, we observed another human cardiac ultrasound. The investigation was to find cures for hypertension in arteries. It was fascinating to see the four-chambers of the heart using ultrasound. We also learnt that the ventricles can be filled both passively and actively from the atria, as the opening of the atrioventricular valves can be long or short. As Guy’s Hospital, is another campus of King’s College, we were able to
visit an environmental lab, at Guy’s, where conditions including
On Thursday, a presentation delivered by Professor Shattock,
temperature and oxygen levels can be altered to mimic different
discussed the near death of Fabrice Muamba. The most likely
environments. Back at St Thomas’ we met a PhD student who
conclusion reached was ventricular fibrillation, since Muamba,
was conducting research into a cure for heart failure by using
a footballer, was too young and fit to have suffered a heart
a, medically instigated, failing guinea pig heart. Although the
attack. However, it also led to the possibility of hypertrophic
heart had been removed from the animal it was still beating and
cardiomyopathy being the cause of his near death, where the
appeared remarkably alive.
muscle was so large it obstructed the flow of blood throughout
Visiting the animal research section, more specifically Dr
the heart. We were also fortunate to gain deeper insights into
Clark’s laboratory, we saw how ultrasound was performed on
the autonomic, sympathetic and parasympathetic nervous
mice. The mouse under investigation is placed in a box and
systems, tachycardia, bradycardia and the role of the vagus
is anaesthetised via a delivery tube. It is then attached to a
nerve.
heating pad, as mice lose heat very quickly. A rectangle of fur
On our final day Dr Albee, taught us how to use micro-pipettes.
was then shaved off the mouse, as fur traps air which would
We learnt how to calibrate them, and extract DNA from a
absorb the ultrasound. Upon application of the gel and probe,
strawberry. In the afternoon, Dr Albee taught us genotyping,
we observed the animal’s heartbeat on a screen and noted clear
protein quantification and how to interpret protein ladders
differences between a mouse and human ultrasound.
during electrophoresis [Figure 3]. We also learnt about Western
On Wednesday, we met Dr Eykyn, who gave us an introduction
blotting or immunoblotting. In the final part of the day Dr Heads
to MRI and NMR Spectroscopy. We learnt about the history of
showed us confocal microscopy and how to operate a very large
the discoveries related to magnetic resonance and how to read
microscope.
NMR spectra; where each peak signified a particular proton environment and the peak intensity correlated with abundance. In the laboratory, where a vertical NMR spectrometer [Figure 2] stood, we learnt that the instrument was a superconductor and was kept cold by several litres of liquid nitrogen and helium. However, in the centre was a heated coil, insulated from the outside to allow living tissue to be studied. We were taught how to assign the various peaks on the produced NMR spectrum, of glucose, to different proton environments in the molecule. We also saw a human MRI scanner in operation, where clear images of the patient’s heart and internal organs were being transmitted. In the afternoon we met Dr Chung who was investigating the levels of sodium, calcium and phosphorus in cardiac tissue during heart failure. She anaesthetised a rat and subsequently removed its heart. Once cleaned, the heart was attached to an apparatus which pumped in a blood mimicking solution, to keep the heart alive. The beating heart, in a test tube, was placed in a MRI scanner, where fluctuations in the levels of phosphorus, calcium and sodium were observed.
Figure 3 Protein ladder
I think the placement was very useful as I learnt about the role of a scientist, in a hospital setting. I realised that there was a diverse range of jobs, from working with animals to conducting research on volunteer patients. It gave me a realistic view of the day to day work of a scientist, perhaps pointing me in the right direction for my future career.
Figure 2 NMR Spectrometer
Scientific Research Work Experience Report
51
Engineering Work Experience at a Global Aerospace Defence Company Daniel Malekyazdi L6R1 Name of organisation: Leonardo (Aerospace Company)
The first day started with a drive up to Luton’s Capability Green business park, a beautiful area home to many large companies,
D
uring the summer 2019, I was fortunate to spend a week of work experience at the global defence aerospace company Leonardo, at their Luton site.
The site specialises in electronic warfare capability, where in conjunction with many national air forces around the world, they have helped develop countermeasures and protection for military jets. Much of the work undertaken by the company is restricted and therefore some sections and projects of the
the site, had taken place prior to arrival and we were all given ID cards for the week. During the first day, we were given a brief tour of the premises as well as a small ice breaker for all involved in the work experience programme. One of the main themes noted during the three days of work experience is how systems engineering is incorporated in all types of engineering, and a model we were introduced to was
company were not allowed to be showcased to us. However,
the V-shaped systems model (Figure 1).
during the week an enriching course was delivered to us,
This model was the basis of what we were taught. Furthermore,
providing an inspiring insight into what engineers do at large
basic engineering ideas like stakeholders and their concerns
aerospace research companies.
were introduced to us through simple examples like the
Figure 1 The V-shaped systems model
52
via the M1. Security checks, due to the restricted nature of
Engineering Work Experience
shopping trolley, where as a group we brainstormed various
The anechoic chamber is a closed room which prevents almost
requirements different people have. We were then given
all electromagnetic waves (and sound in some cases) from
projects for the next three days to work on which involved
leaving the room. Therefore, the engineers and scientists at
making a noise detector, which would express the level of
Leonardo can test their radar jamming equipment without the
ambient noise by lighting up a series of LEDs. This involved
possibility of external interference. Upon entering the room
the fundamental levels of electrical engineering and allowed
(Figure 2) voices sounded different as hardly any echoes occur.
a better insight into what these engineers do. Altogether, this
Furthermore, we were given the opportunity to handle the
project was a success and had us soldering and assembling all
former Eurofighter Typhoon’s computer chips, which were used
the parts together to make a neat and effective device.
by one of the most advanced fighters in the world.
The most interesting aspect of the experience was catching
In all, this was an extremely enriching experience where we
a glimpse into the projects and facilities in use in the Luton
were shown very theoretical, applied and practical approaches
building. We got the opportunity to enter the anechoic chamber
to engineering and I would fully recommend it to anyone
which was hidden on the lower floors and involved passing
considering pursuing a career in electrical engineering or a
through a sophisticated air lock system to enter, preventing any
similar discipline, as it was a highly enjoyable week.
possible contamination from the outside world.
Figure 2 Anechoic chamber
Engineering Work Experience
53
The 2019 Nobel Laureates The Nobel Prize in Physics 2019 The 2019 Nobel Prize in Physics are awarded “for contributions to our understanding of the evolution of the universe and Earth’s place in the cosmos”, with one half to James Peebles “for
This year’s Nobel Prize in Physics rewards new understanding of the universe’s structure and history, and the first discovery of a planet orbiting a solar-type star outside our solar system.
theoretical discoveries in physical cosmology” and the other half jointly to Michel Mayor and Didier Queloz “for the discovery of an exoplanet orbiting a solar-type star.”
Figure 1 Physics Nobel Laureates: Peebles (Left), Mayor (Centre), Quelo (Right)
The Nobel Prize in Chemistry 2019 The 2019 Nobel Prize in Chemistry are awarded to John Goodenough, M. Stanley Whittingham and Akira Yoshino “for the development of lithium-ion batteries”. Through their work, they have created the right conditions for a wireless and fossil fuelfree society, and so brought the greatest benefit to humankind.
The Nobel Prize in Chemistry 2019 rewards the development of the lithium-ion battery. This lightweight, rechargeable and powerful battery is now used in everything from mobile phones to laptops and electric vehicles. It can also store significant amounts of energy from solar and wind power, making possible a fossil fuel-free society.
Figure 2 Chemistry Nobel Laureates: Goodenough (Left), Whittingham (Centre), Yoshino (Right)
54
The Nobel Laureates
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The Immune Response to Covid-19
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The Change in SI units
How Technology is revolutionising Botany Robotic Plants
Shiv Choraria
Lucas Valladares
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Are Humans still Evolving?
Nobel prizes 2019
Theo Silverbeck
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Globally, as of 2:06pm CET, 31 October 2020, there have been 45,428,731 confirmed cases of COVID-19, including 1,185,722 deaths, reported to WHO.
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www.habsboys.org.uk @habsboysschool /habsboys @habsboys
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Scope – The Scientific and Technical Journal of The Haberdashers’ Aske’s Boys’ School
2020, Issue 31