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Seasonal nomadism, migration, and resettlement have always been important for the people living in the northern Polar Regions as these movements are key for their survival. In the past, such movements were usually triggered by the local conditions which their continued existence is affected by activities such as aggregation in temporary winter villages near the sea ice for seal hunting and summer dispersal inland looking for wild reindeer.

There are two types of screening programs – proactive and opportunistic. Proactive screening uses population registers to invite people to be screened at regular intervals, while opportunistic screening targets people attending health services for unrelated reasons.

The value of opportunistic chlamydia screening is being called into question.

Dr Nicola Low, an epidemiologist at the University of Berne in Switzerland argues that claims about screening are not supported by rigorous research or practice.

Starting to breed late in life is a bad idea if you want to maximise the number of offspring that you produce - or so the theory goes.

But doubt has now been cast on this hypothesis - one of the biggest assumptions in behavioural ecology - by researchers from the universities of Bristol and Cape Town and published today in Current Biology.

Teens who are most physically active and consume the most calories are the leanest, researchers say.

Mating strategies are straightforward in bottlenose dolphins, or are they? Much of the work carried on male-female relationships in that species to date show that males tend to coerce females who are left with little choice about with whom to mate. This explains the complex relationships we observe in male bottlenose dolphins, which are only paralleled by human social strategies: the formation of alliances and alliances of alliances, also called coalitions.

In the hands of the wrong person, power can be dangerous. That's especially the case in the workplace, where the abuse of power can lead to sexual harassment.

We are used to hearing about the effects of climate change in terms of unusual animal behaviour, such as altering patterns of fish and bird migration. However, scientists at the University of Birmingham are trying out an alternative bio-indicator – the king penguin – to investigate whether they can be used to monitor the effects of climate change.

Given the choice, many of us would opt for warmer climes during the bleak midwinter. However, most of us cannot afford to move abroad for a few months, so instead we pile on extra layers of clothing to keep warm. Arthropods face much the same dilemma, as they cannot migrate long distances to avoid low winter temperatures – so why are they not killed off by the cold?

Rabies, a relentless, ancient scourge, may hold a key to defeating another implacable foe: HIV. Scientists at Jefferson Medical College in Philadelphia have used a drastically weakened rabies virus to ferry HIV-related proteins into animals, in essence, vaccinating them against an AIDS-like disease. The early evidence shows that the vaccine – which doesn’t protect against infection – prevents development of disease.

J. B. S. Haldane once famously quipped that "God is inordinately fond of beetles." Results of a study by Mark A. McPeek of Dartmouth College and Jonathan M. Brown of Grinnell College suggest that this fondness was expressed not by making so many, but rather by allowing them to persist for so long. In a study appearing in the April issue of the American Naturalist, McPeek and Brown show that many insect groups like beetles and butterflies have fantastic numbers of species because these groups are so old.

A new molecular "fishing" technique developed by researchers at Duke University and Duke's Pratt School of Engineering lays the groundwork for future advances in hand-held sensing devices.

Hand-held devices used for medical testing or environmental and food-safety monitoring could quickly and precisely measure concentrations of virtually any chemical substance, including blood proteins, toxic pollutants and dangerous biological agents, in a test solution, according to the researchers.

Whose tastes do you trust more? The person who loves the same things you love? Or the person who hates the same things you hate? Turns out, when we’re looking for advice, positivity reigns. A new study reveals that we trust those who love the same things we love more than those who hate the same things we hate. As the researchers explain in the March issue of the Journal of Consumer Research, "There are few ways that products are loved, but many ways that they are hated."

Cartilaginous fishes (sharks, rays, skates, and chimaeras) are the phylogenetically oldest group of living jawed vertebrates. They are also an important outgroup for understanding the evolution of bony vertebrates such as human and teleost fishes. In a new study published online this week in the open access journal PLoS Biology, Byrappa Venkatesh, Sydney Brenner, and colleagues performed survey sequencing (1.4× coverage) of a chimaera, the elephant shark (Callorhinchus milii).

In the event of a nuclear or radiological catastrophe -- such as a nuclear accident or a “dirty bomb” -- thousands of people would be exposed to radiation, with no way of quickly determining how much of the deadly substance has seeped inside their bodies. Scientists at Duke University Medical Center have developed a new blood test to rapidly detect levels of radiation exposure so that potentially life-saving treatments could be administered to the people who need them most.

Researchers at Delft University of Technology can predict how nanostructuring – the extreme reduction of structure – will affect the performance of Li-ion batteries. The nanostructuring of battery materials is likely to be common practice in the future, but it is not always performance-enhancing. The research findings have recently been published in the Journal of the American Chemical Society.