Monday, 8 December 2014

Gender diversity in science: where are all the women?

Gender diversity is such a big issue today, especially when it comes to STEM subjects. There is no doubt gender diversity in STEM has improved over the last few decades but there is still a severe imbalance: only 13% of all STEM jobs in the UK are taken up by women, and if you disregard jobs in medicine, that figure drops to 9%. Academic careers in STEM also suffer from a gender imbalance, and what is striking is how the proportion of women at each level of increasing seniority drops: for example, in the physical sciences, though women take up 42% of postgraduate places, they only take up 10% of professor positions. The full set of statistics, put together by Scienceogram UK, can be found here (and it’s definitely worth a look).

So why is this the case? In February earlier this year, the House of Commons published a report (here) on this very subject. They pick out two primary explanations for the lack of gender diversity in STEM careers. Firstly, gender biases, which are largely unconscious, both influence employers away from recruiting women and also influence women themselves from pursuing STEM careers. Secondly, the nature of the early academic career structure tends to deter women more than men from pursuing academic careers: it is composed of short-term contracts, often not more than a year or two, which often require international relocation. It seems that women are more likely than men to give up an academic career in light of the job insecurity and instability that results.

How can we tackle these issues? It’s not easy: unconscious gender biases are so ingrained in our society, and the fact that we are not aware of them makes them so much harder to combat. The House of Commons report has recommended providing STEM undergraduates and postgraduates with equality and diversity training, also noting that such training should be mandatory for all STEM recruiters and line managers, which is a start.

Tackling the barriers presented by the academic career structure is equally difficult, but for different reasons: the career structure is based on a complicated set of factors, constrained by the way in which Higher Education Institutions (HEIs), research councils and other funding institutions work. This makes changing the structure much more difficult. And, as the government points out in their response to the House of Commons report, published in May (here), the contract lengths of academic positions is ultimately the choice of the HEIs, meaning the government have limited say in the matter.

It’s not obvious how we can move forward. Perhaps the way to changing the academic career structure is to target the HEIs themselves, or to put pressure on the funding institutions to offer longer-term contracts. Certainly, one way to improve unconscious gender bias is to talk about it, to make us aware of the biases that we may not even realize we have, because this at least gives us a chance of tackling them.

Thursday, 2 October 2014

Thursday, 18 September 2014

A Look at Our World: Leidenfrost Effect

If a pan on a stove gets hot enough, you can see something quite strange. Normally, pouring a few drops of water onto a hot pan results in the water fizzling into steam, disappearing within seconds. But on a pan that is very hot, the water in fact coalesces in to shapes of smooth marbles, which skitter across the pan like they are dancing. Try it!

This surprising phenomenon is called the Leidenfrost effect and has a simple explanation. If a surface is hot enough, the lower part of the liquid that touches it vaporises so quickly that it forms a layer between the pan and the rest of the liquid. This layer actually acts as an insulator, across which the water can skitter without immediately evaporating, protected from the heat of the pan. The exact temperature at which this phenomenon starts to take place depends on many factors, but for water on a pan, the pan's surface temperature is likely to be at around 200 degrees celsius.

Wednesday, 6 August 2014

Trying to Understand Climate Change (II)

James Lovelock has said that he expects about 80% of the world's population to be wiped out by 2100.

Lovelock is surely one the most influential scientists today. His extreme views on the impacts of climate change has brought all-important publicity to the issue, and his Gaia hypothesis, first ignored by almost all, then ridiculed by some, has been gradually accumulating support over the years.

Lovelock believes that by 2020 extreme weather will be frequent, and that by 2040, much of Europe will have become a part of the Saharan desert and parts of London will be underwater. Though they sound dramatic, his claims aren't too different from the claims in the IPCC's Fifth Assessment Report (see part II), and indeed have the added benefit of making the severity of our situation inescapably clear.

Lovelock's book 'The Revenge of Gaia' does a good job at explaining his view on climate change, and how we should act in light of it. Firstly, what is 'Gaia'? Gaia is the Earth, its atmosphere and all living organisms on it. The Gaia hypothesis proposes that Gaia forms a single complex system that self-regulates its environment to optimise it for life sustenance, much as our bodies self-regulate themselves to maintain the internal conditions that best enable us to thrive.

The self-regulation mechanisms take the form of negative feedback loops. Take, for example, the following feedback loop that may regulate the Earth's surface temperature: let us say that temperatures increase for whatever reason, warming the ocean surface waters. It is thought that ocean algae produce a chemical substance, called dimethyl sulphide (DMS), that contributes to cloud formation. When the ocean surface waters warm, production of DMS increases, and thus cloud coverage increases. However, since clouds cool the Earth by reflecting incident sunlight back into space, the increased cloud coverage works to reduce temperatures back down again. Thus, temperature can be regulated.

However, a number of positive feedback loops also exist. For example, if the ocean surface water temperatures surpass a certain threshold (and a few degrees can make all the difference), its surface waters become devoid of nutrients. Algae die, and DMS production reduces, decreasing cloud coverage. The decreased cloud coverage allows more sunlight onto Earth, thus increasing temperatures further, exacerbating the problem.

Self-regulation means that temperatures would not normally surpass this threshold, but human carbon dioxide emissions, for example, are leading to a hotter Earth, causing the positive feedback loop to kick in. There are many such positive feedback loops now in play, and it is this that makes Lovelock so concerned about our fate: the Earth is going to get increasingly hot, and the world as we know it is going to undergo some serious changes as a result.

So what does Lovelock suggest we do? According to him, it's far too late to try and save the planet: temperatures will increase, deserts will spread and cities will become submerged by water. According to Lovelock, what we have to do is give up trying to save the planet, and use technology to make the world one in which we can live in: we need to synthesise our own food, air-condition our cities, and, crucially, use nuclear power for energy because renewables just won't cut it.

Lovelock's prognosis may seem dark, but the more I read about what he has to say, the more I can't help but agree that we, as a human race, are in serious danger.

Tuesday, 22 July 2014

Science Says | Missing: Titan's Waves. If found report to NASA

A post exploring the mysterious and exotic world of Saturn's largest moon, Titan. Find it here.

Image: NASA's Cassini Spacecraft under creative commons license

Monday, 30 June 2014

The Politics of the Longitude Prize

As a global society, we face a number of issues that need to be addressed urgently. The Longitude Committee chose six of these, and formed six scientific challenges that, if answered, would help solve these issues. Just last week, the public decided that the most worthy challenge was the one that addresses the rise in bacterial resistance to antibiotics.

The challenge involves developing a cost-effective, reliable and swift means for testing for bacterial infections, which health professionals can use to prescribe the right antibiotics at the right time. This would reduce the frequency with which antibiotics are unnecessarily prescribed, and will thus help slow the growth of bacterial resistance. The Longitude Committee have promised to award a prize of £10 million to the candidate who best answers the challenge.

What I like about the Longitude Prize is that it emphasises the role that science has to play in addressing our greatest global challenges. It thus publically re-affirms the important status of science in society, something that can be often undermined. It also inspires people to use science to address these global challenges, people from both our current workforce and from the next generation’s. As such, I have no doubt that the Prize will drive some important positive results.

However, in emphasising the role that science has to play in addressing these challenges, critics are concerned that it does too little to highlight the pivotal role of politics. Indeed, even if a practical means of testing for bacterial infections were found, political action would be absolutely necessary to ensure that the equipment was actually distributed and used. As Jonathan Mendel puts it, writing on the Guardian, the Longitude Prize leaves us “seduced by hopes that science will solve our social and political problems” although, single-handedly, it most certainly can’t. The worry is that the Longitude Prize thereby fosters political inaction.

In my view, the Longitude Prize may well “seduce our hopes that science will solve our social and political problems”. However, I think it is very important to realise that this is not due to any fault in the Prize itself. Rather, it is a lack of sufficient political action and awareness that makes us vulnerable to becoming “seduced”.

It is extremely important to promote scientific action, and the Longitude Prize does this well. What we need alongside this is political action, because without them in tandem, we haven’t a hope of solving our greatest global challenges.

Science Says | A Little Matter of Light

My first blog post for Science Says explores how scientists will soon be turning pure light into matter. Take a look, here!

Image: Pretty Lights under creative commons license

Thursday, 29 May 2014

Trying to understand Climate Change (I)

There is no doubt that climate change is becoming one of the most important issues on the news agenda, and rightly so: if there's one thing we can be sure about, it's that this is an issue that needs to be addressed. But, beyond that, I find it very hard to understand what's going on. What exactly is causing climate change? How exactly is our climate changing? And what should we, as individuals and as a global society, do about it?

There are a few reasons I think that make this such a complex topic. Firstly, there are numerous components to our climate system, and the components are notoriously 'chaotic' (i.e. if the model used to make predictions is just slightly inaccurate, the resulting predictions may be wildly inaccurate). As such, the exact details of the issue at hand tend to be vague and uncertain. Secondly, because the issue is not exactly clear, it's hard to know how to address it: should we attempt to resolve it, or is mitigation the most we can hope for? How much do we need to reduce our CO2 emissions by to be safe? And some questions are made even more complex by the political agendas surrounding them: Should we invest in renewables or is nuclear a better alternative? How much responsibility should lie with developing nations compared to developed nations?

What I'd like to do is start looking into these issues more, to gain a better understanding of what our best science tells us is going on. So I've started by looking at the papers from the IPCC (Intergovernmental Panel on Climate Change), who aim to provide a rigorous and balanced scientific view on climate change and its impacts. In particular, I've taken a look at their most up-to-date report, the Fifth Assessment report, in order to help me get a better understanding of the scientific consensus.

I've picked out a few claims from the report that I think set the landscape for how our best science views climate change. You'll see that claims have been usefully qualified by confidence and probabilistic measures:
  • "Warning of the climate system is unequivocal...The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, sea level has risen, and the concentration of greenhouse gases have increased."
  • "It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century."
  • "Continued emissions of greenhouse gases will cause further warming and changes in all components of the climate system. Limiting climate change will require substantial and sustained reductions of greenhouse gas emissions."
  • As a result of the changes in climate in the recent decades, with high confidence: a large fraction of terrestrial and freshwater species face increased extinction; and low-lying areas will increasingly experience adverse impacts such as submergence, coastal flooding, and coastal erosion. 
  • In addition, also with high confidence, all aspects of food security are potentially affected by climate change; and climate change is expected to lead to increases in ill-health in many regions and especially in developing countries with low income, as compared to a baseline without climate change.
I'm sure none of this is a surprise to you, and it wasn't much of a surprise to me either. But, for me, seeing these claims in a well-reputed scientific report, rather than as second-hand claims in an article (or blog-post!) certainly helped give these claims more grounding.

And that comment, I think, touches upon another reason that makes climate change such a complex topic: it's so hard to know whether what you read and hear is true, or whether it has in some way been corrupted, either intentionally or inadvertently. Indeed, as suggested by George Monbiot's recent criticism of James Lovelock's latest book, even the most highly-respected sources may get their facts wrong.

So on that note, here are the links to the original documents of the IPCC's Fifth Assessment Report - or at least their Summary for Policy Makers - for you to take a look at yourself:

Part 1: The Physical Science Basis
Part 2: Impacts, Adaptation and Vulnerability
Part 3: Mitigation of Climate Change

And here is the link to the website:

Next time, I'll be looking at the ideas of the fascinating and sparky James Lovelock so keep a look out.

Monday, 21 April 2014

A Look At Our World: Tree Bark

The bark of a tree has some wonderful textures to it: smooth, scaled, cracked, ridged, or some combination of these. There are generally two layers of bark, the outer layer and inner layer. Inside of these are the notable rings of wood that increase in number each season as the trunk grows to expand its girth. It is this growth that tends to cause the outer layer of bark to crack and peel away, giving it some of its distinct textures. Interestingly, it is not uncommon for the inner layer of bark to have the ability to photosynthesise, and if you scratch at the surface of a twig with your nail, you may expose a surface with a greenish tinge, indicative of the presence of chlorophyll, a requisite for photosynthesis.

In this very close-up photo of tree bark, you can see the top layer of outer bark peeling away to expose the inner bark. You can also see a greenish tinge, though whether this is the chlorophyll in the tree or perhaps some common tree lichen, I am not quite sure!

Saturday, 8 March 2014

The Power of Nuclear Fusion

Our world is in something of a environmental crisis. It seems that our unquestioning use of the Earth's resources, combined with an exploding population, has resulted in changes that could be detrimental to our civilisation: water levels are increasing, natural food resources are running out and our main energy sources won't last a great deal longer.

Because of this, green, sustainable energy is imperative: green, so as to minimise our production of atmospheric carbon-dioxide levels, which is already well above 'safe' levels, according to climatologist Dr James Hansen; and sustainable so that it can meet the demands of an increasing population and their rising standards of living.

For me, all this makes the ITER project of immense interest. Involving 35 nations and costing 13 billion Euros, this large scale experiment aims to demonstrate the potential of nuclear fusion as a source for future commercial energy.

Nuclear fusion is the process that powers our Sun, enabling it to emit the light and heat energy that lights and warms our Earth. Current commercial nuclear power plants generate energy by a process called nuclear fission, which works by splitting a heavy atomic nucleus into two lighter ones. Nuclear fusion, on the other hand, combines two light atomic nuclei into a heavier one. If these processes are carried out with the right types of atoms, they can generate a huge amount of energy.

The fusion process can be carried out by fusing hydrogen nuclei into a helium nucleus. Hydrogen, found in seawater, is abundant on Earth, and, as such, we'd have enough fusion fuel to last millions of years. Furthermore, it produces no carbon dioxide during operation and no radioactive waste that puts so many off nuclear fission.

So why aren't we currently using fusion to generate commercial energy? Unlike fission, fusion requires extremely high temperatures. Creating these conditions and managing them safely is a challenge. Furthermore, producing these high temperatures requires a lot of energy, and although experimental groups have generated energy using fusion before, no experiment has been able to generate an overall surplus of energy.

The ITER machine, currently being built in France, aims to be the first experiment to achieve this. Designed to fuse hydrogen atoms in conditions ten times hotter than the core of the Sun, ITER hopes to generate ten times as much energy as is put in. The construction, which began in 2010, is scheduled to be completed in 2020, with fusion operation beginning in 2027. But, the technological challenges presented by this ambitious project are already resulting in delays, and even if ITER does achieve its goal, there is much more testing to be done before fusion energy can be generated for commercial use. Experts think it unlikely to be available for another 40, 50 or even 60 years.

There is a long way to go before this solution to our energy needs can become a reality, but the ITER project is paving the way.

Wednesday, 29 January 2014

Green Goodness. And a lot of sugar

Whilst deciding what to have for lunch in a local Pret a Manger a few weeks ago, I came across their 'Green Goodness Juice'. Packed with with Goodness, its only ingredients are Apple, Cucumber, Celery, Spinach, Lime, Ginger.

It definitely sounds good, but eyeing up the nutritional breakdown on the back gave me a bit of a shock. Each bottle contains an impressive 42.8 grams of sugar. To put this in perspective, this is the equivalent of more than ten teaspoons of sugar, between 50%-80% of an adult's guideline daily amount (depending on what recommendations you look at); and even their carrot cake slice, the item with the highest sugar content I could find on the menu, has less sugar at 36.2 grams.

I should point out a few caveats: clearly, the Green Goodness Juice has additional nutritional content that the Carrot Cake Slice does not; and the Carrot Cake Slice is a reasonably small portion (112g), whereas the Juice is reasonably large (400g). Nevertheless, these statistics do make me wonder how 'good' the 'Goodness Juice' really is, and whether the 'naturalness' of the sugars make its high sugar content admissible.

There are different types of sugars, the main categories being 'glucose', 'fructose' and 'sucrose'. Sucrose is commonly known as table sugar, and is made up of both glucose and fructose in equal parts. Since sucrose is immediately broken down into its component parts on ingestion, the body only really distinguishes between glucose and fructose.

Glucose can be used for energy by all the cells in our bodies, and is circulated around the body to this end. Any glucose that is not needed by the body is stored for later use, eventually as fat. However, fructose can only be used for energy by a few types of cells, liver cells being the most significant. Fructose is also stored as fat, if not used. There are numerous ongoing debates as to which of these sugars is better or worse. Many arguments point towards fructose as being the worse of the two, due to the by-products created in liver upon metabolism, and its inability to dull our feeling of hunger. However, these accusations have not been shown conclusively, and there are various other arguments in favour of fructose.

So back to the natural sugars in out Green Goodness Juice. Natural sugars are made of both glucose and fructose, though proportions vary depending on the product. Apples and pears have a particularly high fructose content, but many other fruit and vegetables, for example, pineapple, peaches and carrots have an approximately equal ratio. As mentioned, table sugar is also made up of glucose and fructose in equal ratio. So, it seems, there is often little difference between natural and added sugars.

It should be emphasised that this is not to say that there is little difference between eating fruit and eating cake. Not only does fruit offer nutrients that the cake will not, but whole fruit will most likely have a lot less sugar per serving, and the fibre in whole fruit will slow the body's absorption of the sugar, reducing the negative impact it might have on you. Fruit juice, on the other hand, may be packed full of nutrients, but will contain more sugar per serving and less fibre.

So where does all this leave our Green Goodness Juice? Well, it certainly has nutrients aplenty, unlike the Carrot Cake slice. But it also has a whole lot of sugar, which is not redeemed in virtue of it being natural, and nor does it boast the fibre that absolves whole fruit. I guess whether it is 'good' or not really depends on how much other sugar you'll be eating throughout your day: as my grandmother quips, 'Everything in moderation'.