Category Archives: Biological Sciences

Less and Less Baby Polar Bears with Melting Arctic Ice

We all know of the strong correlation between changes in the environment and the polar bears,but a recent study suggests that the population of this species, Ursus maritimus, could be in real danger with the decline of Arctic sea ice specifically in our country’s Hudson Bay.

Source: Flickr

Article published on February 8th, 2011 in Nature Communications outlines a study conducted by Peter K. Molnar et al. from the University of Alberta who used mechanistic models to predict changes in litter size of cub polar bears for pregnant females in the western Hudson Bay population under expected changes in sea ice.

Sea ice is vital for the polar bears because during the winter feeding season they rely on the solid floes to take them near the waters where there are lots of food source – seals. But with temperatures rising and early breakup of the ice sheets, the bears are forced ashore sooner than in the past. Moreover, “on shore, there is no food available for them,” as the lead author of the study puts it. Thus the bears, particularly females of reproductive age, are storing up less energy for the months that they have to hibernate during pregnancy.

The researchers found that ~28% of pregnant females already failed to reproduce for energetic reasons during the 1990s. Using mechanistic models, they predicted that if spring sea ice break-up happens 1 month earlier than during the 1990s – 40-73% of pregnant female polar bears could fail to reproduce, and if the break-up happens 2 month earlier55-100% could fail. On a global perspective, the study states that a similar litter size decline trend may be found in over 1/3 of the polar bear population.

What’s even more discouraging is that “the litter size predictions provided in this study serve as another indicator that the western Hudson Bay population will probably not remain viable under predicted climatic conditions” as the article states.

Heart wenching video that hits home of malnourished  mother polar bear and starving cubs as an example of the conditions that polar bears are and will be facing in the future with current climate change conditions. A Warming Climate Takes its Toll on the Polar Bears of Hudson Bay by Daniel J. Cox

WARNING: NOT FOR THE SENSITIVE SOULS.

Shaking up what we knew about shaken baby syndrome

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Keeping infants safe is important.

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But is shaking as harmful as it is made out to be?

When infants arrive in emergency with spinal injuries and bleeding in the brain, doctors are often quick to point the finger at the caregiver. Recently more and more evidence supports mechanisms other than shaken baby syndrome as the cause of such injuries in infants.

The cover story of The New York Times Magazine from Feb 2 2011 explores the issue and the implications for people who have been charged under these circumstances.

NYTMag cover

New York Times Magazine cover image

When caregivers are on trial for child abuse, lawyers use doctors to testify how the injuries of the child were inflicted. More and more doctors are testifying for the defense and in turn exposing the prosecution doctors to the validity of these alternative explanations (such as infant stroke caused by and infection).

This article is not discounting shaken baby syndrome as a real problem, but claims that some people have been wrongly accused because the diagnosis was made too hastily.

Some important issues are brought up regarding the use of science in the courtroom.

First of all doctors can be paid for their testimony. I think the outcome should not be reflective of the doctor the accused can afford. When monetary value is placed on the information presented in the courtroom the facts given to the jury can be skewed. Even worse the picture of scientific knowledge presented is not limited to the courtroom; news and media coverage of high profile cases will pass biased scientific information on to the rest of the world.

A particularly relevant point is that jurors may have difficulty understanding the science presented to them, and this can hinder their ability to properly decide on a verdict. What we learn in Scie 300 can have significant impacts on how effectively science is used in the courtroom.

This issue also points out a flaw in the scientific method; conventionally scientists come up with hypotheses which then raise new questions to be tested. Unfortunately when dealing with the law, a hypothesis that is rejected years after it was formulated can have a major impact on those who were wrongfully accused according to the knowledge at the time. Here we have a tradeoff between putting innocent people away and letting a child abuser continue putting children in harms way.

The bottom line still is: never shake a baby.

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