Many measures to curb the obesity epidemic are aimed at young children. It’s a sensible strategy – we know that overweight children have a good chance of becoming overweight adults. Family homes and schools have accordingly become critical arenas where the battle against the nation’s growing waistlines is fought. But there is another equally important environment that can severely affect a person’s chances of becoming overweight, but is more often overlooked – the womb.

Overweight parents tend to raise overweight children but over the last few years, studies have confirmed that this tendency to transcend generations isn’t just the product of a shared home environment. Obesity-related genes are involved too, but even they aren’t the whole story. Research has shown that a mother’s bodyweight in the period during and just before pregnancy has a large influence on the future weight of her children.

For example, children born to mothers who have gone through drastic weight-loss surgery (where most of the stomach and intestine are bypassed) are half as likely to be obese themselves. On the other hand, mothers who put on weight between two pregnancies are more likely to have an obese second child. In this way, the obesity epidemic has the potential to trickle down through the generations, like a snowball rolling its way into an avalanche.

Now, Robert Waterland from the Baylor College of Medicine has demonstrated how the snowball gains momentum by studying three generations of mice that have a genetic tendency to overeat. And using a special diet that was high in folate and other nutrients, he found that he could stop the snowball’s descent and spare future generations of mice from a heightened risk of obesity.

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Which of these strings of letters is easier to remember:  QKJITJGPI or BBCITVCNN?

Chances are, you chose the latter string, where the nine letters are the combined names of three television networks. This neatly illustrates a fundamental property of human memory – that we remember long strings of information more easily if we can break them down into bite-sized chunks. In this case, a nine-letter string can be divided into three lots of three letters. You probably use similar strategies for remembering telephone numbers, credit card details, or post codes.

Now, Lisa Feigenson and Justin Halberda from Johns Hopkins University have found that infants just 14 months old can use the same technique, delightfully known as “chunking” to increase the limited scope of their memories. Their work suggests that this technique isn’t something we learn through education or experience – it’s more likely to be a basic part of the way our minds process information.

You can consciously use chunking to improve your recollection, but we all do it unconsciously to a large degree. In fact, the technique is the reason why we are rarely aware of the pitiful capacity of our working memory – the amount of information we can hold and work with for short periods of time.

For the longest time, psychologists believed that this mental workspace maxed out at seven items ; adults who saw a flashing array of letters or digits could only remember about seven at a time. But even this score is an overestimate. Later experiments which specifically set out to block chunking showed that adults can only store four items at most, while children and the elderly can only cope with three.

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Evolution dances to the tune of death. Killers – be they predators, diseases or competitive peers – can radically shape a species’ life cycles by striking down individuals of a certain age. The survivors respond by changing their “life histories” – a collection of traits that defines their reproductive cycles, including how often they breed, when they start to do so and how many young they have.

If an animal’s adult life is short and brutal, they tend to grow quickly and become sexually mature at a young age – a strategy that maximises their chances of siring the next generation. The Tasmanian devil may be the latest species to switch to this live-fast, die-young tactic, for their adult population is slowly being wiped off by a contagious cancer.

I’ve blogged about the disease before. Known as devil facial tumour disease (DFTD), it was first reported in 1996, when devils first started appearing with horrendous facial tumours. Since then, it has spread across half of the devil’s home range and has cut a swathe through its populations. Hamish McCallum at the University of Tasmania calculated that the disease, if left unchecked, could drive the Tasmanian devil to extinction within 20-25 years.

But amazingly enough, the devils have started to adapt. So fatal is the disease to adults that the devil population is getting younger and younger and Menna Jones, a colleague of McCallum’s, has found that they are starting to reproduce at a much earlier age too. The surviving devils are in a race against time to reproduce before the cancer kills them off.

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There is an old joke that if Spider-Man has the powers of a spider, he really ought to be shooting webs from somewhere less salubrious than his hands. In the films and comic books, Peter Parker is empowered with the powers of a human-sized arachnid through a spider bite. He effortlessly scales walls and ceilings and shoots sticky webs from his wrists. Now, scientists have found a type of spider that does just that.

Like Spider-Man, most spiders can climb sheer surfaces and they do so with two techniques. The most obvious are small claws, called tarsi, that grip onto rough surfaces. Going down in scale, their feet also end in thousands of tiny hairs. These hairs make such close contacts with the microscopic troughs and crests of seemingly smooth surfaces that they stick using the same forces that hold individual molecules together.

But Stanislav Gorb and colleagues from the Max Planck Institute have found that one species of spider uses a third method, which exploits that most characteristic of spider traits – silk. All spider species spin silk from appropriately named organs on their rear ends called spinnerets. But uniquely to spiders, the Costa Rican zebra tarantula (Aphonopelma seemanni) from spins silk from its feet as well.

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If you’ve never had the pleasure of swimming among a coral reef, you might want to get your chance sooner rather than later. Yesterday, the journal Science published the first comprehensive global assessment of the status of the world’s reef-building corals, and it’s results don’t make for comforting reading. Almost a third of the 700-plus species surveyed face extinction; no group of land-living species, except possibly for the amphibians, are this threatened.

A team of 39 scientists led by Ken Carpenter, director of the Global Marine Species Assessment gauged the extinction risk faced by the world’s corals by using the International Union for Conservation of Nature’s (IUCN) famous Red List Criteria. These criteria measure extinction risk by looking at how quickly a population’s size falls over time. That sort of rigorous census data simply isn’t available for most corals, so Carpenter’s team settled for the next-best alternative – the rate at which a species’ habitat is lost within its known range. The results were adjusted for traits, such as the life cycle of each species and how resilient they are to habitat loss.

The results showed that the outlook for corals has worsened considerably in just the last 10 yeras. The team looked at the fates of 704 species and deemed that 176 were Near-Threatened, 201 were Vulnerable, 25 were Endangered and 5 poor species were Critically Endangered. Using earlier data, the team found that had the analysis been done in 1998 (before a mass “bleaching” event killed off large swathes of coral), only 20 species would have been classified as Near-Threatened and only 13 would have made it into the more severe categories.

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It seems that every scientist has an anecdote about being misquoted, misrepresented or otherwise misled by that most seemingly dangerous of foes – the journalist. And yet, a new survey published in Science suggests that beyond the horror stories, conflict between the two professions is much less volatile than you might imagine. To scientists, it seems that journalists are more likely to be back-slapping comrades than back-stabbing adversaries.

The interaction between science and the media is an area close to my heart. I am steeped in it in both my full-time job and my freelance work and I’ve been fortunate enough to have played most of the roles in the journalist-scientist drama. I’ve interviewed scientists for freelance pieces, I’ve been grilled numerous times myself over the phone and the radio, and I’ve been providing media comments for four years.

In the second half of this piece, I’ll provide a few tips for the scientists among you who have to deal with the media. But first, let’s take a look at the survey.

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Imagine watching a movie where every now and then, key frames have been cut out. The film seems stilted and disjointed and you have to rely on logic to fill in the gaps in the plots. Evolutionary biologists face a similar obstacle when trying to piece together how living species arose from their common ancestors. It’s like watching a film with a minimum of footage; the species alive today are just a few frames at the very end, and the fossil record represents a smattering of moments throughout the film’s length.

But the gaps, while plentiful, are being slowly filled in. With amazing regularity, new fossils are being unearthed that bridge the gap between existing specimens. These “transitional fossils” are always greeted with great relish for their intermediate nature provides yet more examples of gradual evolution from one form to another. They act as handy visual aids for explaining the story of evolution to those with a dearth of imagination.

Now, Matt Friedman from the University of Chicago has described a new transitional fossil that is one of the most dramatic yet. Its name is Heteronectes (meaning “different swimmer”) and it’s a flatfish, but not as you know it.

You’ve probably eaten flatfish before but tasty fillets of plaice, sole or halibut give few hints about their extraordinary physical specialisations. They are fish that live on their sides and their flat profiles make them both efficient hunters and difficult prey. For other fish, lying sideways would give one eye a useless view of sand but flatfish have adapted accordingly. Their fry resemble those of other fish but as they grow, one of their eyes makes an amazing journey to the other side of its head. The adults look like they’ve swum out of a Picasso painting.

But Heteronectes is a half-committed flatfish. Like modern representatives, its skull is asymmetrical and one eye has begun migrating to the other side of its head. But it hasn’t made it all the way round and stops near the midline without crossing to the other side. No living flatfish has eyes arranged in such a way. We couldn’t have wished for a better intermediate form – it’s a marvellous half-way form between the standard fish body plan and the distorted visages of flounders and soles.

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New parents are often extremely picky about where they live, seeking the right combination of spacious housing, local schools, and safe neighbourhoods for their tiny sprogs. A mother mosquito is no less choosy but unlike the white-picket-fence ideal of middle-class humans, she prefers areas of stagnant water, including artificial ones like rain-filled buckets or clogged drains.

But she’s not looking for just any old bucket of sluggish water. A new study reveals that a pregnant Aedes aegypti mosquito seeks out just the right patch by tasting for chemicals given off by bacteria in the water. When her young hatch, bacteria will be their only food and to make sure that they are well-fed, she looks out for a special blend of fatty acids at very precise concentrations.

That’s interesting in itself, but there are obvious practical applications too. If we know the exact balance of chemicals that entice female mosquitoes to lay in certain patches of water, we can manipulate their behaviour and for Aedes aegypti, that’s certainly worth doing.

This species is the main carrier of yellow and dengue fevers, a devastating combination of tropical diseases that affects over 50 million people every year in 100 different countries. Dengue fever in particular is on the ascent in Asia and has recently spread to Central and South America. Clearly, something must be done and among the many strategies being considered, pregnant females present obvious targets.

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“Out, damn spot! Out I say!” In Macbeth’s fifth act, Lady Macbeth’s role in the treacherous murder of Duncan takes its toll, and she begins obsessively washing her hands to alleviate her guilty conscience. Now, some four centuries after Shakespeare penned his play, scientists have found that physical and moral cleanliness are just as inextricably linked as he suggested.

The link between bodily cleanliness and moral purity is evident throughout the world’s cultures. Cleansing ceremonies are common in religions. Christians and Sikhs literally wash away their sins through baptism, while the act of wudu sees Muslims prepare for worship by cleaning their bodies. Our language too reveals hints of an overlap – a ‘clean conscience’ is free of guilt, while ‘dirty’ is a word for thieves and traitors.

Chen-Bo Zhong from the University of Toronto and Katie Liljenquist from Northwestern University have now revealed the strong links between unblemished hands and stain-free hearts in a series of clever psychological experiments.

They asked two groups of people to remember a good or bad deed from their past. Afterwards, the volunteers solved a simple word puzzle by filling in the missing letters in three incomplete words: W_ _H, SH_ _ER and S_ _P. Remarkably, those who remembered unethical deeds thought of cleaning-related words, like shower, wash and soap, about 60% more often than other words that could equally have fit, like wish, shaker and step. Those who remembered ethical actions showed no such preference.

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There can be few events more devastating for a parent than cot death – the sudden and unexpected death of a baby. Cot death is more formally known as Sudden Infant Death Syndrome (SIDS) and it is an apt title, for affected babies often seem outwardly healthy and show no signs of suffering. Studies have suggested that things like passive smoke and breastfeeding can affect the risk of SIDS but the underlying biology behind the syndrome is a mystery, as is the cause of death in most cases.

But it’s a mystery that’s slowly being solved. The latest and most intriguing clue comes from Enrica Audero from the European Molecular Biology Laboratory, working together with European researchers and a special strain of mice. Audero has shown that altering the balance of the signalling molecule serotonin in the brainstems of mice can lead to sudden demise, in a way that resembles the unexpected death of SIDS babies. The mice spontaneously go through “crises” where their basic body functions like temperature control and their heartbeat go haywire.

Audero’s work builds on research published by an American group two years ago, which first suggested that SIDS is the result of faults in the way our brains reacts to serotonin. This signalling chemical helps to control the core functions of our body that lie outside the realm of conscious thought. It’s the serotonin system that lords over our heartbeats, breathing, sweating and shivering, while our brains are busy processing blogs or solving Su Dokus.

Through a series of post-mortem exams, David Paterson showed that SIDS babies have more serotonin-releasing neurons, but a lower density of serotonin receptors – protein docks that the molecule sticks to. It was a start, and Audero capitalised on it by showing for the first time how an altered serotonin network could actually lead to sudden death.

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