Neuroscience is finding itself at the center of a growing controversy in the courtroom. Will judges weigh biological evidence that could suggest future dangerous activity or impaired control differently and how will that affect systems of sentencing and determinations of guilt in the court? This biological evidence could be considered “mitigating” or decreasing a sentence (their brain is broken, it’s not their fault) or it could be “aggravating” (their brain is broken and they will offend again) and increase a sentence. To test whether Judges would reason differently after receiving biological evidence in a trial, a group has conducted a study on U.S. state trial judges. Continue reading “Guilty of a Broken Brain”
Aphids, the scourge of many a gardener, may be the first insect found to use photosynthesis (in addition to wrecking your lettuce). It seems a bit greedy to eat up all of my tomato plants if you can still make energy just basking on the shriveled remains of my plants. Photosynthesis is the process of generating chemical energy from light energy derived from the sun. This puts aphids in the category of the most advanced organisms using photosynthesis including sea slugs and salamanders. In addition, plants, algae and some bacteria have been known to use this process to fuel their energy needs.
Aphids are small insects that feed on a great number of plant species. They have been shown to make their own carotenoids, molecules necessary for oxidation control or light detection. This is the first animal known to make it’s own carotenoids and not require them from their diet.
A new article in Nature shows very early evidence that aphids are using these carotenoids to generate chemical energy from the sun’s light energy. While the evidence is still preliminary, aphids could turn out to be much more than just plant sap suckers. It still doesn’t make me feel any better about my garden.
Next month I will be boarding a flight at Dulles International Airport. The last flight I took was also out of Dulles and I became familiar with their security screening; almost every security line passes through one of the backscatter x-ray scanning machines. Normally, I’m pretty cavalier about most things but when agreeing to undergo a whole body x-ray, outside a hospital, I’d like to know the risks. In 2010, a group of scientists at UCSF, including a biophysicist and an oncologist, wrote a letter to the Assistant of Science and Technology reporting directly to the president, voicing their serious concerns about the safety of these devices. They felt that the data presented by the manufacturer was misleading and did not appropriately address whether this high dose of x-rays into the skin was truly safe. Fellow blogger Mike addressed this issue back in 2010. Since the time of the letter, there has been little research done on actual scanners because “security concerns” prevent the TSA from allowing scanners into public hands.
Several radiologists have stated that these scanners are probably not harmful to those who travel just a few times per year. It is possible that older people, children and pregnant women are at a greater risk of DNA damage from ionizing radiation. It is also a public health concern when a large population of Americans who travel frequently or work in airports, are screened very often. A recent scientific study shows evidence that these x-rays delivered at the specification of the scanning machine, can deliver radiation to internal organs. These specifications also assume that the scanning machine is operating properly. Between May 2010 and May 2011 there were 3,778 service calls made about mechanical issues with back-scatter machines.
But why expose people to x-rays at all? Fellow blogger Josh has written about the cost benefit ratio involved in deciding whether risk of x-ray exposure is worth the potential to stop a terrorist. If there is a technology which can also detect non-metallic objects without delivering ionizing radiation, then its use should be promoted. An alternative to the backscatter x-ray is the millimeter wave scanning technology, which many airports already use. This method eliminates the worry that there may be potential side effects of screening all passengers and screening some passengers a great number of times.
For now, my choice is x-ray induced superpowers or a TSA pat-down. I’ve always wanted a superpower.
I first heard about experimental evolution while reading “The Greatest Show on Earth” by Richard Dawkins. In my naïve view, how could anyone really perform experiments on evolution? Doesn’t it take millions of years? The chapter referenced the E. Coli Long-Term Experimental Evolution Project. I was blown away by the fact that this lab was taking advantage of the short reproduction and life cycle of E. Coli to study evolution in the lab.
I was reminded of this great experiment the other day by an article about another lab studying experimental evolution using microalgae instead of E. Coli. Sinead Collins leads a group in the UK that is studying how microalgae respond to changes associated with ocean acidification or increased levels of carbon dioxide. They have found that while these algae use carbon to complete photosynthesis, they are sensitive to overly high levels of carbon. In an acidic environment, the algae start to get “syndromes” and fail to use up the increased carbon available to them. This goes against the beliefs of many that say that the aquatic life will simply use up the increased carbon in an acidified ocean.
These two groups have each found an organism and a method that will allow them to study evolution experimentally in the lab.
For a time in graduate school, my research involved the use of zebrafish. We would collect and freeze eggs and sperm from the fish to provide a back-up for our stocks. While I’m not a zebrafish expert, freezing these stocks efficiently enough to generate a viable embryo after thawing is extremely challenging. Therefore, I was really impressed by a project to build a coral “sperm bank” described in a recent NY Times article. These sperm banks could be the best tool to preserve the biodiversity of our oceans, both by saving the coral and consequently preserving the coral-based habitats of over one million species.
Stationary coral are especially vulnerable to changes in their immediate environment. Many also have very irregular and inefficient methods of breeding. This “sperm bank” approach will be critical for the coral that are dying off at an alarming rate. Approaching conservation by building banks of sperm, however, may signal that scientists are beginning to realize our efforts at environmental conservation are failing. This leads to some important questions. Should scientists be pursuing better ways to preserve sperm and eggs of all endangered species at the cost of traditional conservation measures? Should more funding for sperm banks be included in budgets for environmental conservation? Conservation will buy time to preserve these species, but is time running out?