Adapting to arsenic

The dose makes the poison. However, that dose may not be the same for everyone. A recent study shows that a human population of the Argentinean Andes has genetically adapted to a polluted environment and increased its resistance to arsenic toxicity.

Natural selection is one of the mechanisms driving evolution and is central to the notion of adaptation: individuals that possess characteristics beneficial to their survival and reproduction in a given environment are likely to produce more offspring than other individuals; as they pass on the beneficial traits to their descendants, these characteristics become more and more common in the population. Continue reading


Time is money

I usually write my posts in both English and French, and the French version of this blog is part of C@fé des sciences, a community of bloggers dedicated to communicating science in French. This week, C@fé des sciences chose to focus on one particular theme: time. Although I did not have time to contribute a full blog post, I couldn’t help but try to think of what I would have written otherwise. The first topic that came into my mind was something I had recently read about: the fact that, nowadays, many people feel pressed by time, and that, according to a poll done in the US in 2011, the wealthier a person is, the more time-poor they feel. Continue reading

Modeling an epidemic to help guide public health policies (Ebola, West Africa)

Projected daily hospital demand in 2015 for Ebola patients in Liberia if 85% of cases are hospitalized.By mid-December 2014, about 18,000 individuals had been reported to be infected by the Ebola virus currently causing an epidemic in West Africa. On January 12, 2015, the World Health Organization’s (WHO) latest report stated an updated total of more than 21,000 cases. As a substantial proportion of cases remain unreported, however, the true number of infected individuals is believed to be much higher. The fatality rate (the proportion of infected people dying from the infection) for this Ebola epidemic, based on known cases, is estimated to be about 70%. Continue reading

Breakthrough of the year 2014 and runners-up

As for the last two years, my first post of this new year will be an overview of the ten scientific advances the editors of Science deemed the most notable of the year (see here for 2013 and 2012).

Breakthrough of the year 2014: the Rosetta mission

Most likely, you’ve already heard of the Rosetta mission’s little lander, Philae. Continue reading

Four questions about the Ebola virus

In its 30 October issue, the journal Nature published a news feature about some of the scientific questions surrounding the Ebola virus and more generally the family of viruses it belongs to. If you are interested in knowing more about Ebola, I recommend reading the whole article (free access). Alternatively, here are the main points: Continue reading

Book review: Countdown, by Alan Weisman

Published in 2013, the book had been waiting on one of my shelves for a while (I do have quite a bit of a backlog), and now that I have finally had time to read it, I want to take a bit more time to, well, tell you to read it.

In Countdown: Our Last, Best Hope for a Future on Earth, Alan Weisman, a journalist and nonfiction writer, addresses head on an issue that most people avoid: the ever growing human population, the environmental, ecological, and social burden it carries, and what it means for the future of not only all other living beings, but also our own species. Continue reading

In brief (October 2014): immunology, sea levels, gender stereotype, and nanomedicine

A selection from what I’ve read over the past couple of months:
immune response and genetic variation, or how interindividual genetic variation affects immune cell behavior, contributing to differences in how people respond to pathogens and how susceptible they are to develop autoimmune diseases,
ice melting and sea rising, or how global seal levels and ice volumes have changed over the past 35,000 years,
gender and speaking up, or how stereotypes related to gender affect an individual’s decision to contribute his/her ideas to a group,
anticancer nanomedicine, or how nano should nanoparticles be to optimally penetrate tumor tissue and exert their anticancer effect. Continue reading

Thoughts on World Mental Health Day

Yesterday was World Mental Health Day, with the theme for 2014 being “Living with schizophrenia”. Perhaps not as popular as any given cancer initiative. Or diabetes day. And yet.

The brain is an organ like any other in our bodies, but we don’t react to diseases of the mind the way we react to diseases of the heart, pancreas, etc. Once upon a time, people whose brains were “malfunctioning”, i.e. not functioning like those of the majority of human beings, were declared “crazy” or “retarded” and were more or less discarded from society. Fortunately, things have improved, but there is still a lot of stigma out there. Continue reading

Lactase persistence and natural selection

Here is an interesting post on John Hawks’s blog: Selection and lactase persistence.

After reading an article by John Hawks in Scientific American (No, Humans Have Not Stopped Evolving), a reader reached out to him, asking for clarification about a point that left him puzzled: why would a genetic mutation that allows lactase persistence after weaning age (meaning the lactase enzyme keeps being produced in adults so that they can still efficiently digest the lactose in milk) stick around in a population when it (apparently) does not confer a direct advantage in survival/reproduction? Continue reading

Pediatric respiratory tract infections and antibiotics: overprescribing?

10344775_815628761791470_2583354142570698374_nAntimicrobial resistance is a serious threat to human health. As the WHO global report published in April 2014 highlighted, it is no longer a concern for the future but happening right now, in every part of the world. It threatens to undo many of the achievements of modern medicine that allow people to live longer and healthier.

A number of concerted actions are needed to tackle the resistance problem, and one of them is to improve the way antibiotics are currently used, both in agriculture and in medicine. Mostly, this means curbing antibiotics use.

A study published in the journal Pediatrics in October tried to assess how often antibiotics were prescribed in cases of acute respiratory tract infections in children in the US in relation to how often these infections actually involved bacteria (many of these infections are indeed caused by viruses). Continue reading