Tuesday 30 April 2013

Science Highlights of the Week - Sixth Edition


Stubble is Sexy.
A study in Australia has investigated how much of a man's socio-sexual standing, as perceived by woman and other men, is based around their facial hair.
Photographs of ten men were taken when they were clean shaven, after five days of stubble growth, ten days and then after six weeks of growth (full beard). These images were shown to a mixed group of volunteers who rated each photo for the qualities of sexual attractiveness, general health, masculinity and parenting abilities.
The study found that both men and woman ranked the fully bearded images as highest for masculinity, parenting abilities and health. The perception of three qualities were seen to increase linearly with facial hair growth.
However, whilst the men reckoned the fully bearded guys were also the most attractive, women ranked men with thick stubble (10 days of growth) as most sexually appealing. This perception could be linked to previous studies which have found that women tend to judge men with much thicker facial hair as more aggressive.
Gonorrhea is Getting Serious.
Antibiotic resistance is a rapidly increasing (and well documented) problem in many diseases and with over 17, 000 gonorrhea infections identified and treated in the UK last year it is no surprise that the drugs are beginning to fail.
The antibiotic ceftriaxone is the only drug used to successfully treat the common STI but cases of gonorrhea recorded in Canada, America and parts of Europe that have not responded to antibiotic treatment are on the rise. Currently, about 6% of gonorrhea infections diagnosed in Canada are not treatable with available antibiotics.
Untreated gonorrhea can lead to serious complications in both men and women as the bacteria can spread through the body, causing pelvic inflammatory disease and eventually affecting joints and heart valves. In women, long term infections can lead to infertility.
Whilst cases of resistant infections are still low, but it has been predicted that by 2015 these cases will be more common than the treatable strains. It is not likely that a new antibiotic will be developed by this time.
The Evolution of the Penis
Four researchers at the University of Georgia have published a study of how the evolution of the human penis has been affected by mate selection by females. In comparison to other closely related primates, the human penis is disproportionately large. From an evolutionary stand point, this is an interesting phenomenon as it seems selection for reproduction was precopulatory rather than post-, i. e. reproductive selection was not just dependent on sperm survival but on what the paper has described as "cryptic female choice".
There are many factors that determine mate choice and this study focused purely on the visual. The study involved the use of artificially generated images of men of varying heights, penis size and hips:shoulders ratios - in total 343 different figures were produced. These were shown to heterosexual women who rated their attractiveness as sexual partners (and before you start wondering, all the penises depicted in the study were flaccid).
Taller males with wider shoulders were consistently selected as most attractive, independent of penis size. However once individual factors were taken into account, for example, at one given hip:shoulder ratio, penis size had a small but significant increase in perceived attractiveness. Interestingly, after controlling for hip:shoulder ratio, penis size elevated relative attractiveness far more strongly for taller men than for shorter ones.
The relationship between penis size and attractiveness was not linear; a considerably larger-than-average penis (more than 2 standard deviations from the average of 8.9cm) made for a less attractive figure.
Most research into female attraction has shown that height and wide shoulders are the most important factors in mate selection but the findings in this paper does suggest that selection on penis size was potentially as strong as selection on stature back before humans began to habitually wear clothing.

Wednesday 17 April 2013

Science Highlights of the Week - The Fifth Edition


Scientists Try To Make Mice Puke
Rodents are unable to vomit, a response which is seen in almost all other mammalian species. Researchers at the University of Pittsburghnoted this, and looked it to the phenomenon.
A range of rodents (from mice and rats to mountain beavers) were given chemicals that would induce vomiting in other mammals. However no retching or vomiting was seen.
It is thought that a mixture of anatomical constraints (the rodent aesophagus is very long and not fully muscled) and an absent neurological component is behind this odd trait.
An Alternative Approach Against MRSA
Antibiotic resistance is one of the greatest challenges modern medicine is going to have to face. New antibiotic drugs are expensive to develop and few have been produced in recent years.
Scientists at the Rockefeller University’s Laboratory of Bacterial Pathogenesis and Immunology have shown that the use of bacteriophages (think viruses that attack bacteria) as a means of infection control.
So far, they have seen success in curing mice infected with either MRSA or Anthrax using this approach without development of antibacterial resistance being seen. Whilst human clinical trials are a long way off at this time, this is a very promising step towards the next generation of antimicrobial drugs.
Paranoid? So is Everyone Else.
In a paper published in Current Biology, researchers observed that people would assume that the gaze of others was directed at them, especially in low lighting or when the other was wearing sunglasses.
This is possibly because we have evolved, as a species, to utilise gaze to determine if we are being faced by friend or foe. The direction of another's gaze is used to provide insight into their focus of interest, and simple ego assumes that we are the most interesting thing around.
What's wrong, honey?
Using fMRI scans, researchers have seen that men are, in fact, less able to read a woman emotional states that they are another man's. It seems that this may be due to a difference in brain activity between the genders.
Participants in the study were shown different faces and asked to judge the mood that that person was feeling as their brains was watched for activity. The function of the amygdala is thought to be key in empathy, but when men looked at women's faces, there was not as much neural activity seen in that location. Yet when they looked at men's images, activity was seen and more correct answers were given.