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Monday 21 September 2015

Location, Location, Location

Nuclear power and nuclear waste are sensitive public issues. Whilst the Finns are already building a geological disposal facility in Onkalo, in the UK we still haven’t decided what to do with our waste. Before the site can be chosen and built, a formal, scientific safety case must be completed, evidencing the likelihood that the containment facility will remain intact on a timescale of at least thousands of years. Learning from the “Yucca Mountain controversy”, where the state of Nevada legally opposed the construction of an American disposal facility on the grounds that they didn’t want to be lumbered with the country’s nuclear waste without consent, the UK government are waiting for volunteer communities to emerge before they can even start studying local geology in detail. Huge climate and geological changes, including at least one ice age, are predicted, which would totally change the landscape, the exact impacts of which could vary widely depending on where nuclear waste goes.

Low-level waste storage pit at the Nevada National Security Site
Nuclear waste is divided into three categories: High, Intermediate and Low Level Waste. High Level Waste is what's left after spent fuel is recycled to extract as many reusable uranium and plutonium fuel isotopes as possible. This waste is usually vitrified: transformed into a glass by fusing with borosilicates at high temperature. Intermediate and Low Level Wastes are non-fuel items (such as containers) that have been or may be been contaminated during normal operation of the nuclear power plant, and comprise the bulk of the waste. Image credit: Nevada Test Site Guide (public domain)

Tuesday 8 September 2015

Do cheaters prosper?

Attempting to selfishly gain an immediate advantage in a situation where others are co-operating is called social cheating. Many people are likely to bitterly recall an experience of this, queue jumping is a classic example, and a wide variety of other organisms undergo the same injustices. Cheaters in theory should have an evolutionary edge, but social co-operation remains at the base of almost all populations. This is a mystery that scientists have been intrigued by for years, as there is very little we really understand about these behaviours and how they co-exist.

Social systems can be ‘modelled’ in much simpler organisms than us; the social amoeba for example. Dictyostelium discoideum (Dicty), are generally alone throughout their lives, but for one 10 hour period. This time is where they become social in order to release spores that will grow into new amoebae. To do this they form ‘fruiting bodies’, where some Dicty give up their lives and harshly but more importantly; their bodies. These form a stalk, the top of which the spores can be released from. However some Dicty cheat - there are amoebae that climb straight to the top to release their spores and contribute less to the stalk. By doing this they release more spores than other, co-operating amoebae and so gain an evolutionary edge, passing on more of their genes. But this advantage cannot be significant, as otherwise they would overrun the co-operators and drive them to extinction.

Photograph of stalked slime mould fruiting bodies, by Lairich Rig (CC BY-SA 2.0)
The Dicty amoebae begin as single celled organisms, before congregating as a multicellular ‘slug’, which then gives rise to fruiting bodies with spores atop long stalks. In the species shown here, each of the sporangia was 2-3mm tall. Image credit: © Lairich Rig, via geograph (CC BY-SA 2.0)

Wednesday 2 September 2015

The Inspirational Butterfly

An Insight into Developments in Solar Power

The UN is calling for drastic action to be taken to stop climate change in its tracks. With any luck an agreement will be reached this year on the actions that will need to be enforced by 2020 to tackle this worldwide issue[1]. As a result, countries are desperately attempting to reduce their carbon emissions, and focus on renewable energy sources is increasing. If the right developments are made to improve efficiency and distribution of renewable sources, we could be one step closer to establishing a sustainable worldwide energy supply and battling the ongoing threat of climate change.

The prospect of being able to harness energy from the Sun is one that has captured our interest given its relative reliability, and solar power is already a widespread phenomenon. However it does not yet compare to the cost of generating power from fossil fuels, and a result is often considered to be less economically viable.

Electrical apprentice Eric Penel works on the solar reference array, which has been installed on the roof of the Shaw Theatre at NAIT's Main Campus in Edmonton.
The UN conceded in the Kyoto Protocol that limiting global warming to just 2 degrees, relative to the pre-industrial temperature level, would be necessary to reduce harmful climate impacts. For this to be achievable a 75% decline in carbon emissions by 2050 would be necessary[2]. If innovations in solar power continue to progress at the current rate, it could become the world's largest energy source by 2050. Today, solar photovoltaics and concentrated solar power contribute 16% and 11% to global overall consumption, respectively[3]. Image credit: Northern Alberta Institute of Technology via Flickr (CC BY-ND 2.0)

Given the positive effect a switch to solar power could have on the climate, there is much ongoing research into whether the efficiency of solar power can be improved. Inspiration for this goal can sometimes be found in the most unlikely of places..