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New and Exciting in PLoS this week

Just because I am galivanting in Lindau does not mean I could not take a look at the brand new papers published in PLoS ONE, PLoS Biology, PLoS Medicine and PLoS Neglected Tropical Diseases last night. A few titles caught my eye – take a look. As always, you should rate the articles, post notes and comments and send trackbacks when you blog about the papers. You can now also easily place articles on various social services (CiteULike, Mendeley, Connotea, Stumbleupon, Facebook and Digg) with just one click. Here are my own picks for the week – you go and look for your own favourites:

Characteristics of Medical Research News Reported on Front Pages of Newspapers:

The placement of medical research news on a newspaper’s front page is intended to gain the public’s attention, so it is important to understand the source of the news in terms of research maturity and evidence level. We searched LexisNexis to identify medical research reported on front pages of major newspapers published from January 1, 2000 to December 31, 2002. We used MEDLINE and Google Scholar to find journal articles corresponding to the research, and determined their evidence level. Of 734 front-page medical research stories identified, 417 (57%) referred to mature research published in peer-reviewed journals. The remaining 317 stories referred to preliminary findings presented at scientific or press meetings; 144 (45%) of those stories mentioned studies that later matured (i.e. were published in journals within 3 years after news coverage). The evidence-level distribution of the 515 journal articles quoted in news stories reporting on mature research (3% level I, 21% level II, 42% level III, 4% level IV, and 31% level V) differed from that of the 170 reports of preliminary research that later matured (1%, 19%, 35%, 12%, and 33%, respectively; chi-square test, P = .0009). No news stories indicated evidence level. Fewer than 1 in 5 news stories reporting preliminary findings acknowledged the preliminary nature of their content. Only 57% of front-page stories reporting on medical research are based on mature research, which tends to have a higher evidence level than research with preliminary findings. Medical research news should be clearly referenced and state the evidence level and limitations to inform the public of the maturity and quality of the source.

Racial Differences in the Human Endogenous Circadian Period:

The length of the endogenous period of the human circadian clock (tau) is slightly greater than 24 hours. There are individual differences in tau, which influence the phase angle of entrainment to the light/dark (LD) cycle, and in doing so contribute to morningness-eveningness. We have recently reported that tau measured in subjects living on an ultradian LD cycle averaged 24.2 hours, and is similar to tau measured using different experimental methods. Here we report racial differences in tau. Subjects lived on an ultradian LD cycle (1.5 hours sleep, 2.5 hours wake) for 3 days. Circadian phase assessments were conducted before and after the ultradian days to determine the change in circadian phase, which was attributed to tau. African American subjects had a significantly shorter tau than subjects of other races. We also tested for racial differences in our previous circadian phase advancing and phase delaying studies. In the phase advancing study, subjects underwent 4 days of a gradually advancing sleep schedule combined with a bright light pulse upon awakening each morning. In the phase delaying study, subjects underwent 4 days of a gradually delaying sleep schedule combined with evening light pulses before bedtime. African American subjects had larger phase advances and smaller phase delays, relative to Caucasian subjects. The racial differences in tau and circadian phase shifting have important implications for understanding normal phase differences between individuals, for developing solutions to the problems of jet lag and shift work, and for the diagnosis and treatment of circadian rhythm based sleep disorders such as advanced and delayed sleep phase disorder.

Seasonal Hunger: A Neglected Problem with Proven Solutions:


Most of the world’s acute hunger and undernutrition occurs not in conflicts and natural disasters but in the annual “hunger season,” the time of year when the previous year’s harvest stocks have dwindled, food prices are high, and jobs are scarce.

We know what works in fighting seasonal hunger and undernutrition: there are identifiable policy and program successes in contexts around the world, but they often operate on a small scale and in isolation.

Community-based interventions to treat acute undernutrition and promote growth of preschool children are examples of successful interventions that should be scaled up.

Global scale-up of a basic “minimum essential” intervention package against seasonal hunger would cost around 0.1% of global GDP and save millions of lives, while protecting millions more from severe illness.

Focusing on seasonal hunger would be an effective way to leverage resources for the attainment of the hunger-related Millennium Development Goal.

Bad Taste Protects Fruit Flies from Eating a Toxic Amino Acid in Plants:

Besides enhancing the pleasure of eating, our sense of taste can steer us away from poisonous foods. Many plants, for example, produce bitter-tasting toxins, such as caffeine and quinine, to deter predation by herbivores from cows to insects. But it remains a mystery how animals developed their capacity to detect–and so avoid–the tens of thousands of plant toxins, which include alkaloids, phenolics, and nonprotein amino acids. The best-known toxic nonprotein amino acid is L-canavanine, which accumulates in the seeds of alfalfa (Medicago sativa) and many other leguminosae. L-canavanine is so similar to the amino acid L-arginine that it gets incorporated into proteins, rendering them dysfunctional. A few insects have developed strategies for counteracting this toxin, including larvae of the beetle Caryedes brasiliensis, which depend entirely on seeds of the legume Dioclea megacarpa and catabolize L-canavanine into harmless compounds. However, the vast majority of insects are susceptible to L-canavanine, and little is known about their ability to detect it in plants.

Clean Water Should Be Recognized as a Human Right:

At the March 2009 United Nations (UN) meetings coinciding with the World Water Forum, Canada, Russia, and the United States refused to support a declaration that would recognize water as a basic human right. The special resolution proposed by Germany and Spain, and endorsed by the President of the UN General Assembly, was instead rejected in favor of further examination of issues of access to safe drinking water and sanitation [1].

Opposition to this declaration runs counter to considerable evidence that access to clean water, which is essential for health, is under threat. According to the World Health Organization, 1.2 billion people worldwide do not have access to clean drinking water, and a further 2.6 billion lack adequate sanitation services. These numbers are expected to rise. The UN has estimated that 2.8 billion people in 48 countries will be living in conditions of water stress or scarcity by 2025 [2].

Parks and Tourism:

Why should it matter how many people visit national parks? In a word: politics. Protected areas are not only physical places, reservoirs of biodiversity, and sources of ecosystem services, such as breathable air and drinkable water. They are also human political constructs, and they are under ever-increasing pressures from growing human populations and resource demands. Visitors may bring them the political capital to survive.

Biologists have pointed out for decades that protected areas are not playgrounds, but life-support systems for the planet’s population of humans, as well as its other species. Economists estimate that ecosystem services worldwide contribute twice as much to the human economy each year as all forms of human industry combined–many trillions of dollars [1],[2]. At regional scale, ecosystem services from National Wildlife Refuges in the contiguous 48 states of the Unites States have been valued at US$27 billion annually [3]. The human economic value of conserving biodiversity is many orders of magnitude higher than the funds invested in it [2],[4]-[9]. The cost of buying all of the world’s biodiversity hotspots outright has been estimated at around US$100 billion–less than five-years’ expenditure on soft drinks in the US [10]. But the actual funds allocated worldwide each year, a few billion dollars in total, are <5% of minimum requirements for effective conservation [11]. This compares with the trillions of dollars spent in 2009 to prop up financial systems in the US, European Union, and China [12].