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Scientists use maggots to help solve murders Money
worries can dent your intelligence Trends Prof Yash
Pal
THIS UNIVERSE |
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Scientists use maggots to help solve murders Flies feeding off dead flesh in a Gothic tower and a suitcase with a pig’s head in an overgrown garden are the sort of things you expect to see in a horror movie — but for scientists at the Natural History Museum they are crucial to research in the fight against crime. At the top of the south-west tower of the London museum, stillborn piglets are laid out in a room with open windows to see how long it takes for flies to lay their eggs on the decomposing flesh. Meanwhile, in the wild garden at the side of the museum, a pig’s head bought from a local butcher for £3 is locked in a small suitcase on the ground to see whether flies are able deposit their eggs through the zip — and how long it takes if they can. Forensic entomology — the study of insects to solve crime — has already helped to put several murderers behind bars and researchers at the NHM are working with the forensic arm of the Metropolitan Police to discover new insights into the murky world of the flesh-eating blowfly. One of the most notorious cases was the murder of a health worker, Leah Questin, by her boyfriend Clinton Bailey. Leah’s badly decomposed body was found in a suitcase in Kent and the time of her death — determined by the blowfly maggots on her body — formed a critical piece of the evidence that led to Bailey’s conviction in 2010. The type and number of insects living off a decomposing body can be crucial to working out when someone has died. Estimating time of death with conventional forensic techniques gets increasingly difficult after several days, said Martin Hall, a blowfly specialist at the museum. “We’re trying to simulate a suitcase disposal here in the museum’s wild garden. This one here may be laying eggs. You can see she’s a female because her eyes are wide apart,” Dr Hall said yesterday, pointing at a fat fly sitting on the suitcase zip. “We want to know how sealed the environment of a suitcase is and this kind of work shows that a zip can be quite leaky. We’ve found that some zips are more leaky than others.” A study underway at the museum has shown how easy it is for blowflies to lay their eggs through the tiny gaps in the sealed zips of a suitcase — still a popular method for disposing of a dead body. Poulomi Bhadra, a research scientist at King’s College London, keeps a collection of zips and blowflies in another room at the top of a stone staircase leading up the south-west tower, where the smells of rotting flesh waft safely away over London rather than over the museum visitors. “We’re testing a range of zips to see how easy it is for blowflies to lay their eggs through them. It’s quite surprising how they can wiggle their eggs through the gaps,” Bhadra said. There are 20 species of blowfly in the UK but only a handful are known to lay their eggs on human flesh. How quickly the eggs develop depends on the species as well as the ambient temperature — blowflies can even lay eggs in winter if it is a sunny day. An important part of the forensic entomologist’s job is to be able to name the precise species found on a body, Dr Hall said. “Putting a name on the evidence is critical to an investigation. Getting the wrong species can introduce an error of three days in estimating the time of death,” he said. — The Independent
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Money worries can dent your intelligence Money worries temporarily make you
less intelligent according to studies showing that people with less
cash to spend do less well than richer people in IQ tests. Scientists found that poorer people faced with a large, unexpected bill perform significantly worse than they would otherwise have done without the financial worry hanging over them. The
difference, according to the studies, was equivalent to as much as 13
IQ points on an average scale of 100, which is equivalent to the
temporary mental impairment caused by the loss of an entire night’s
sleep, the scientists said. “Our results suggest that when you’re
poor, money is not the only thing in short supply. Cognitive capacity
is also stretched thin,” said Sendhil Mullainathan, an economist at
Harvard University who took part in the research published in the
journal Science. “What we show is that the same person
experiencing poverty suffers a cognitive deficit as opposed to when
they’re not experiencing poverty… your effective capacity gets
smaller because you have all these other things on your mind - you
have less mind to give to everything else,” Dr Mullainathan said. One
of the studies was carried out on about 400 shoppers in a New Jersey
mall who were asked to carry out standard cognitive tasks. Half of
them, however, were asked a “teaser” question about how they would
deal with an expensive car repair. The poorer shoppers in this group performed significantly worse than the richer shoppers. They also did more badly than the poorer members of the other group who did not have to contemplate the teaser question about the expensive car repair. “For
the poor, because of these monetary concerns are just below the
surface, the question brings [these concerns] to the top. The result
was, for that group, the gap between the rich and the poor goes up, in
both IQ and impulse control. There was no gap in the other group,”
he said. A second study was carried out on 464 sugarcane farmers in
India who took IQ tests before and after the annual harvest — when
they receive most of their income — the farmers performed far worse
before the harvest, when they were technically poorer, than after the
harvest. “The month after the harvest they’re pretty rich, but
the month before, when the money has run out, they’re pretty poor.
What we did is look at the same people the month before an the month
after the harvest, and what we see is that IQ goes up, cognitive
control, or errors, goes way down, and response time goes way down,”
Dr Mullainathan said. “The effect here is about two-thirds of the
size of the effect found in the mall study. It’s at least nine or
ten IQ points, just between these months,” he said. Eldar Shafir
of Princeton University, who part of the study, said: “Previous
views of poverty have blamed poverty on personal failings, or an
environment that is not conducive to success. We’re arguing that the
lack of financial resources itself can lead to impaired cognitive
function. The very condition of not having enough can actually be a
cause of poverty.” — The Independent
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Trends WASHINGTON: Getting depressed when it's cold outside may not be as common as we have been led to believe, a new study has suggested. In the study, researchers found that neither time of year nor weather conditions influenced depressive symptoms. Lead author David Kerr of Oregon State University said this study does not negate the existence of clinically diagnosed seasonal affective disorder, also known as SAD, but instead shows that people may be overestimating the impact that seasons have on depression in the general population.
Mouse body clock study offers clues to possible jet lag cure LONDON:
Scientists have found a genetic mechanism in mice that hampers their body clock's ability to adjust to changes in patterns of light and dark, and say their results could someday lead to the development of drugs to combat jet lag. Researchers from Britain's Oxford University and from the Swiss drug firm Roche used mice to analyze patterns of genes in an area of the brain called the suprachiasmatic nuclei, which in mammals pulls every cell in the body into the same biological rhythm. Fukushima radioactive plume to reach US coast in 3 years SYDNEY: A recent study has revealed that the radioactive particles leaked by the crippled Fukushima nuclear plant into the Pacific Ocean will reach the US coastline within three years of the incident. The study showed while atmospheric radiation was detected on the US west coast within days of the incident, the radioactive particles in the ocean plume take considerably longer to travel the same distance. However, it is likely to be harmless, according the journal Deep-Sea Research 1. —
Agencies
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THIS UNIVERSE
The Earth is hot deep inside, and in summer it is hot externally too. This being the case, why does ground water remain cold in summer? During summer in tropical areas, the earth gets a lot of sunshine during the day and is not allowed enough time during night to cool. So mostly it is hot in these areas. Generally, the temperature of the earth's surface is moderate. As we go under the earth's surface, it is a bit cooler because we are protected from the hot sun. But as we descend towards the centre of the earth, it gets warmer. This is fairly uniform over the year. The temperature rises as we go deeper. Indeed, the interior of the earth is perennially hot and gets hotter as we descend. This heat is due to adiabatic compression of gases as also production of heat due to radioactive decay. Why does boiling milk overflow from a container while water does not? We must remember that milk is not an ordinary liquid. It is a colloidal fluid containing many organic materials in a watery mixture. There are several cheesy constituents and significant amount of cream and fat. During heating, light substances come to the surface. This includes every thing but water. They tend to form a connected film. Where this film touches the walls of the heating vessel, it dries up and becomes a bit sticky. As the heating proceeds, the film becomes more substantial and is pushed up by the vapour pressure below it. When the boiling point of water is reached, the film blows up and milk spills out to create an embarrassing mess. Readers can e-mail questions
to Prof Yash Pal at palyash.pal@gmail.com |
Steve Connor
