ScholarScribe

Danger in the air

We've long known that the human body jumps into a state of high alertness when it senses danger. Blood pressure increases, muscles tense up, temperature rises, and now research is revealing that our sense of smell sharpens as well.

In a new study, a team exposed 14 participants to three types of odours: neutral pure odour, neutral odour mixture, and negative odour mixture that contained, among other things, trimethylamine - a compound strongly associated with rotting meat. The researchers then asked participants to detect the presence or absence of the odours while lying in an MRI scanner.

While the participants were being scanned (which is a loud and stressful experience), the researchers measured the skin's ability to conduct electricity (a measurement that is known to track arousal level) and monitored the subjects' breathing patterns. Once the odour detection task was over, and the subjects were still in the scanner, they were asked to rate their current level of anxiety. The authors then analyzed the brain images obtained.

They found that as anxiety levels rose, so did the subjects' ability to notice negative odours, hinting that olfactory acuity increases in response to the body's belief of there being a nearby threat. The researchers also found amplified communication between the sensory and emotional areas of the brain in response to negative odours. Of course, these findings make evolutionary sense. If our ancestors were exploring a cave for potential use as a dwelling, it would be critical that they be able to detect the smell of rotting meat indicative of recent predatory kills. Indeed, failure to notice such smells would have made them vulnerable to being eaten.

This recently published in Chemosensory Perception.

Beeing our own problem

Colony collapse disorder is the crucial problem plaguing honey bee populations around the world and nobody is really certain of what causes it. Some have suggested climate change, some have suggested habitat destruction, others have hinted at pesticides, but these are all shots in the dark. But now a new study is shedding some light on the pesticide idea and indicating that there might really be something to it... but not in the way that many had previously believed.

Rather than consider the possibility that pesticides were directly killing bees off, a team exposed honey bees at a test site to very low doses of pesticides that are often used on crops in regions where bees function as vital pollinators. After several generations were exposed (and several were set aside as controls), the researchers challenged the hives with a common gut parasite. Bees that had long term exposure to the very low pesticide levels readily contracted the gut parasite whereas control bees did not. Read more in my article on this in The Economist.

Flower power

One of the big problems with concentrated solar power plants is that they are, well, big. A 100-meter-high pillar is usually surrounded by rows of giant mirrors rippling outward. More than 600 of these mirrors, each the size of half a tennis court, track the sun throughout the day, concentrating its rays on the central tower, where the sun’s heat is converted into lots of electricity. All of this equipment takes up nearly 60 football (soccer) pitches and makes finding space for such plants a problem.

To work around this, a team developed a computational model to evaluate the efficiency of current plant layouts and noticed that by changing mirror organisation into a spiral layout similar to that found amongst sunflower florets they could increase solar plant efficiency and reduce the space taken up by the overall plant. Read more about this in my article in The Economist.

The bounty of winter

Unlike plant eating animals in seasonal habitats, which eat large amounts of food during the spring and summer but very little in autumn and winter, predators have long been thought to have steady diets. This is now being proved wrong.

A team that analysed the wolves of Yellowstone for 14 years found that the diets of these wolves vary wildly with the seasons and that deepest darkest winter is actually a time of plenty for these beasts. More specifically, they discovered that wolves were least capable of catching and killing adult elk during spring and summer when these prey animals were well fed and strong. With this being the case, the wolves turned to young of the year and deer. These animals were easier to catch than the adult elk, but offered little meat in return for a huge amount of effort. In contrast, the team noticed that tired and hungry adult elk in late winter could be killed by wolves with relative ease.

What this finding presents is the notion that winter may actually be for wolves what spring and summer are for herbivorous animals, something that has not much been considered in ecological circles before.