History of Science

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Scientists Pinpoint Why Some People Become Addicts

2008-02-26 12:18:25 | Weblog

Scientists Pinpoint Why Some People Become Addicts

Drug Addiction
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An Iranian nurse (L) hands a bag of crushed methadone tablets to a reforming drug addict at the Aftab (Sunshine) Society Clinic in Tehran May 20, 2007. Scientists have identified the part of the brain that may hold the key to why some cocaine users become addicts while others just take the drug socially, researchers said on Tuesday.
Scientists have identified the part of the brain that may hold the key to why some cocaine users become addicts while others just take the drug socially, researchers said on Tuesday.

Brain scans of cocaine users while they performed simple computer tasks showed changes in the part of the brain responsible for controlling behavior and making appropriate decisions, they said.

This could explain why some people find it easier to quit than others and may shed light on long-term addiction, said Hugh Garavan, a cognitive neuroscientist at Trinity College Dublin who presented his research to a meeting of the Royal Society in London.

"Most people who try to quit drugs relapse," Garavan said in a telephone interview. "It might have to do with how intact these brain regions are."

Cocaine, initially used in patent medicines, beverages and tonics around the turn of the 20th Century, is a drug that in powdered form can be snorted or dissolved in water and injected. Its derivative crack cocaine is even more powerful.

An estimated 1 to 3 percent of adults in developed countries use the drug, which has been linked to a number of medical, psychological and social problems including crime, violence and the spread of diseases like AIDS and hepatitis, according to the World Health Organisation.

Garavan and colleagues used MRI scans to show that cocaine users had reduced neural activity marked by reduced blood flow to the part of the brain involved in things like problem solving, decision making and controlling behavior. Some people were administered cocaine in the experiments.

"This research helps us move away from thinking of drug dependence as a moral weakness and allows us to see it as more of a medical condition."

It was unclear whether the changes were due to the drug itself or whether some kind of natural mechanism in the brain triggers the change, Garavan said.

But better understanding the brain's response to cocaine could eventually help predict people most at risk of developing an addiction and lead to better treatments, he added.

"One would hope this research would guide the development of new treatments including the development of pharmacological solutions to addiction," Garavan said.

Teenage Anger Linked to Brains: Study

2008-02-26 11:56:08 | Weblog

Teenage Anger Linked to Brains: Study

Teenage Anger
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A teenager in an undated photo. Aggression in some teenage boys may be linked to overly large Amygdalas in their brains, a study by scientists in Australia and the United States has found.
Aggression in some teenage boys may be linked to overly large Amygdalas in their brains, a study by scientists in Australia and the United States has found.

In an article in the Proceedings of the National Academy of Science, they said these boys may also be unable to control their emotions because other parts of the brain that normally control strong emotions don't mature till the early 20s.

"It is important for parents to bear in mind that while their teenage child looks like an adult and does very complicated work at school, parts of their brain are still developing really until the 20s," Nicholas Allen at the University of Melbourne's psychology department said in a telephone interview.

"Those parts of the brain that help the child control his own emotions and behavior ... it's important to realize that these parts of the brain are still developing for these young people."

In the study, 137 12-year-old boys and their parents were asked to discuss sensitive issues, such as homework, bed times and Internet times; and the boys had their brains scanned later.

"Boys who had large amygdalas spent more time behaving in an aggressive way," Allen said, referring to a part of the brain located deep within the medial temporal lobes that is believed to be involved with emotional responses, including arousal and fear.

These boys also appeared to have small prefrontal cortexes, a region of the brain that has to do with regulating emotions.

"What we observed here was that these parts of the brain, when they are less developed in boys, it seems that they are associated with these kinds of behavior, more aggressive and more negative emotions when they interact with their parents."

Photo Tech Complicates Child-Porn Cases

2008-02-25 20:21:29 | Weblog

Photo Tech Complicates Child-Porn Cases

Degital Evidence (Child Porn)Each week, about 100,000 sexually explicit images of children arrive on CDs or portable disk drives at Michelle Collins' office.

They are sent by police and prosecutors who hope Collins and her 11 analysts at the National Center for Missing and Exploited Children can verify that the graphic pictures are real, not computer-generated. When they can't, officials sometimes turn to outside experts.

All this is being done - at an annual cost in the millions of dollars collectively in child-pornography cases alone - as software like Photoshop makes it easier to fake photos and as juries become more skeptical about what they see.

Although challenges to digital photos come in all types of criminal and civil cases, they are especially pronounced in child-pornography cases because of a 2002 U.S. Supreme Court decision striking down a ban on computer-generated child pornography. Defense attorneys are trying to use the ruling to introduce reasonable doubt in jurors' minds about the images' authenticity.

Prosecutors still generally prevail, but "this has certainly created an additional burden," said Thomas Kerle of the Massachusetts State Police. "I can say that unequivocally, it has made the prosecution of these types of cases more difficult. It takes ... resources I think could be better applied to investigating" more cases.

Drew Oosterbaan, who heads the U.S. Department of Justice's Child Exploitation and Obscenity Section, said prosecutors sometimes submit only photos they can easily verify because outside experts can be expensive - with travel, hotels and consulting fees, along with possible delays.

"This can affect the sentence the defendant gets," he said. "Before (the 2002 ruling) we would generally charge all the images."

Oosterbaan added that although defense lawyers have the right - and duty - to challenge evidence, they are doing so without "any shred of evidence there are wholly computer-generated images being generally circulated and passed off as real children out there."

And many law-enforcement officials worry that the time and money needed to withstand any challenges will only grow as technology improves and makes it more difficult to tell a computer-generated image from a real one.

"I feel that pretty much we can tell the difference right now," said Karl Youngblood of the Alabama Bureau of Investigation. "How much longer that's going to last, I don't know with the technology going at the rate it's going."

Of course, there's a cost to defendants as well - sometimes more so because federal law limits where and when the defense may review images to restrict their distribution, meaning experts must often travel with expensive equipment to a police lab in another city.

"If something becomes more difficult for the government to prove, so be it. They have the burden of proof," said First Amendment lawyer Louis Sirkin, lead counsel in the challenge that led to the 2002 Supreme Court ruling.

Child pornography is illegal in the United States, but the Supreme Court in 2002 struck down on free-speech grounds a 1996 federal ban on material that "appears to be" a child in a sexually explicit situation. That ruling covers computer-generated images, though morphing - such as the grafting of a child's school picture onto a naked body - remains illegal.

Collins' Child Victim Identification Program in Alexandria, Va., grew out of that ruling. After officials submit seized photos, the center uses software and visual inspections to look for matches. It can usually verify that children in some or all of the images are known and real.

The program, which costs about $1 million a year to run, now has about 1,300 children in its database, up from 20 in 2002. Staff grew from just Collins then to 11 full-time analysts who now work under her. The program reviewed 5 million images last year, up from about 450,000 in 2003, the program's first full year.

Because of the graphic nature of the images, a psychologist visits each week, and analysts must undergo counseling at least quarterly.

"Not everybody can do it," said Raymond Smith, a longtime investigator who oversees child-exploitation cases at the U.S. Postal Inspection Service. "You have to be able to come to grips with seeing children be victimized and abused. It can tear you up, (but) through your efforts you are identifying the people that hurt these children."

When the center cannot make a match, prosecutors can turn to outside experts. Sometimes, it's a pediatrician who can say a real child has characteristics matching those seen in the photo. Other times it's a computer expert who can talk about how difficult it is to produce images and video of that quality.

Hany Farid, a Dartmouth College professor who has testified for the prosecution in some cases, said he has been getting more inquiries about authenticity - not only for child-pornography cases but also civil lawsuits questioning medical images in malpractice cases or signatures in contract disputes. News organizations have also looking for ways to authenticate photos.

"Because so many people get photographic fakes in their (electronic) mailboxes, to the average juror it resonates," he said.

The challenges can be costly, even if a case never goes to trial - the majority end in plea agreements.

Farid said he charges up to $25,000 a year for software he produced to look for signs of tampering, such as inconsistencies in shadows. He also charges as much as tens of thousands of dollars to work on a case.

Even when there is a match and an expert isn't needed, a prosecutor must seek out the detective who initially identified a child for the center. That detective must often be flown in and be ready to testify if the defense raises a challenge. In one case in Portland, Maine, a Russian detective couldn't be reached, so the prosecutor had to spend $5,000 on an expert anyway. Trials get postponed if a key witness has a scheduling conflict.

Sam Guiberson, a defense attorney who specializes in technology and digital evidence, said challenges to evidence are to be expected, digital or not.

"Every good trial lawyer is always going to subject every part of his adversary's exhibits to that sort of scrutiny," Guiberson said.

Kebin Haller, deputy director of the Wyoming Division of Criminal Investigation, said that in most cases, a large quantity of images are seized such that enough hold up.

How much proof a prosecutor needs in child-pornography cases can vary from region to region and even from judge to judge. Recent federal appellate rulings have eased the burden on prosecutors, essentially saying that in lieu of definitive evidence, they can let jurors make up their own minds about whether an image is real or computer-generated.

Many prosecutors, though, don't want to take that chance and would rather submit proof.

"It's difficult to prove these are real children," said Mary Leary, a Catholic University law professor who previously worked on child-abuse and child-pornography cases. "Is the defense exploiting this? Absolutely they are."

The end is near... well, in 7.6 billion years

2008-02-25 11:35:08 | Weblog

The end is near... well, in 7.6 billion years

The big news: Earth is doomed to fry and then be gobbled up by the dying Sun.

UV Image of the Sun

A NASA-released ultravilet image of the sun. The big news: Earth is doomed to fry and then be gobbled up by the dying Sun.

But don't blow your savings on an Apocalypse Party just yet, for astronomers say the planet's demise is 7.6 billion years away.

The unusual calculations appear in the British open-access journal Astrophysics.

Robert Smith, emeritus reader in astronomy at the University of Sussex, southern England, previously calculated that as the Sun runs out of fuel, it will expand into a dangerous "red giant".

But Earth -- while battered and burnt to a crisp -- would escape ultimate destruction, he had thought.

Smith, working with Klaus-Peter Schroeder at the University of Guanajuato in Mexico, has taken a new run through the figures. Sadly, for our home, the number is up.

"The tenuous outer atmosphere of the Sun extends a long way beyond its visible surface, and it turns out the Earth would actually be orbiting within these very low-density outer layers," Smith says.

"The drag caused by this low-density gas is enough to cause the Earth to drift inwards, and finally to be captured and vaporised by the Sun."

Life on Earth will have become rather uncomfortable before then, however.

A billion years from now, as the Sun slowly expands, the oceans will evaporate, filling the atmosphere with water vapour (a potent greenhouse gas) and triggering runaway global warming.

Smith sketches two options, both admittedly sci-fi in feel, for escaping this fate.

One is to harness the gravitational pull of a passing asteroid to gently tug Earth out of the danger zone.

A wee nudge every 6,000 years could be enough to survive for at least five billion years -- provided a miscalculation does not send the asteroid barrelling into Earth instead of doing a close flyby, says Smith.

"A safer solution may be to build a fleet of interplanetary 'life rafts' that could manoeuvre themselves always out of reach of the Sun but close enough to use its energy," he says.

A Lead on the Ark of the Covenant

2008-02-24 21:31:25 | Weblog

A Lead on the Ark of the Covenant

Ark of Covenant
The Ark of the Covenant is carried into the Temple

When last we saw the lost Ark of the Covenant in action, it had been dug up by Indiana Jones in Egypt and ark-napped by Nazis, whom the Ark proceeded to incinerate amidst a tempest of terrifying apparitions. But according to Tudor Parfitt, a real life scholar-adventurer, Raiders of the Lost Ark had it wrong, and the Ark is actually nowhere near Egypt. In fact, Parfitt claims he has traced it (or a replacement container for the original Ark), to a dusty bottom shelf in a museum in Harare, Zimbabwe.

As Indiana Jones's creators understood, the Ark is one of the Bible's holiest objects, and also one of its most maddening McGuffins. A wooden box, roughly 4 ft. x 2 ft. x 2.5 ft., perhaps gold-plated and carried on poles inserted into rings, it appears in the Good Book variously as the container for the Ten Commandments (Exodus 25:16: "and thou shalt put into the ark the testimony which I shall give thee"); the very locus of God's earthly presence; and as a divine flamethrower that burns obstacles and also crisps some careless Israelites. It is too holy to be placed on the ground or touched by any but the elect. It circles Jericho behind the trumpets to bring the walls tumbling down. The Bible last places the Ark in Solomon's temple, which Babylonians destroyed in 586 BC. Scholars debate its current locale (if any): under the Sphinx? Beneath Jerusalem's Temple Mount (or, to Muslims, the Noble Sanctuary)? In France? Near London's Temple tube station?

Parfitt, 63, is a professor at the University of London's prestigious School of Oriental and African Studies. His new book, The Lost Ark of the Covenant: Solving the 2,500 Year Mystery of the Fabled Biblical Ark (HarperOne) along with a History Channel special scheduled for March 2 would appear to risk a fine academic reputation on what might be called a shaggy Ark story. But the professor has been right before, and his Ark fixation stems from his greatest coup. In the 1980s Parfitt lived with a Southern African clan called the Lemba, who claimed to be a lost tribe of Israel. Colleagues laughed at him for backing the claim; in 1999, a genetic marker specific to descendents of Judaism's Temple priests (cohens) was found to appear as frequently among the Lemba's priestly cast as in Jews named Cohen. The Lemba — and Parfitt — made global news.

Parfitt started wondering about another aspect of the Lemba's now-credible oral history: a drumlike object called the ngoma lungundu. The ngoma, according to the Lemba, was near-divine, used to store ritual objects, and borne on poles inserted into rings. It was too holy to touch the ground or to be touched by non-priests, and it emitted a "Fire of God" that killed enemies and, occasionally, Lemba. A Lemba elder told Parfitt, "[It] came from the temple in Jerusalem. We carried it down here through Africa."

That story, by Parfitt's estimation, is partly true, partly not. He is not at all sure, and has no way of really knowing, whether the Lemba's ancestors left Jerusalem simultaneously with the Ark (assuming, of course, that it left at all). However, he has a theory as to where they might eventually have converged. Lemba myth venerates a city called Senna. In modern-day Yemen, in an area with people genetically linked to the Lemba, Parfitt found a ghost town by that name. It's possible that the Lemba could have migrated there from Jerusalem by a spice route — and from Senna, via a nearby port, they could have launched the long sail down the African coast. As for the Ark? Before Islam, Arabia contained many Jewish-controlled oases, and in the 500s AD, the period's only Jewish kingdom. It abutted Senna. In any case, the area might have beckoned to exiled Jews bearing a special burden. Parfitt also found eighth-century accounts of the Ark in Arabia, by Jews-turned-Muslims. He posits that at some undefined point the Lemba became the caretakers of the Ark, or the ngoma.

Parfitt's final hunt for the ngoma, which dropped from sight in the 1940s, landed him in sometimes-hostile territory ("Bullets shattered the rear screen," of his car, he writes). Ark leads had guided him to Egypt, Ethiopia and even New Guinea, until one day last fall his clues led him to a storeroom of the Harare Museum of Human Science in Zimbabwe. There, amidst nesting mice, was an old drum with an uncharacteristic burnt-black bottom hole ("As if it had been used like a cannon," Parfitt notes), the remains of carrying rings on its corners; and a raised relief of crossed reeds that Parfitt thinks reflects an Old Testament detail. "I felt a shiver go down my spine," he writes.

Parfitt thinks that whatever the supernatural character of Ark, it was, like the ngoma, a combination of reliquary, drum and primitive weapon, fueled with a somewhat unpredictable proto-gunpowder. That would explain the unintentional conflagrations. The drum element is the biggest stretch, since scripture never straightforwardly describes the Ark that way. He bases his supposition on the Ark's frequent association with trumpets, and on aspects of a Bible passage where King David dances in its presence. Parfitt admits that such a multipurpose object would be "very bizarre" in either culture, but insists, "that's an argument for a connection between them."

So, had he found the Ark? Yes and no, he concluded. A splinter has carbon-dated the drum to 1350 AD — ancient for an African wood artifact, but 2,500 years after Moses. Undaunted, Parfitt asserts that "this is the Ark referred to in Lemba tradition" — Lemba legend has it that the original ngoma destroyed itself some 400 years ago and had to be rebuilt on its own "ruins" — "constructed by priests to replace the previous Ark. There can be little doubt that what I found is the last thing on earth in direct descent from the Ark of Moses."

Well, perhaps a little doubt. "It seems highly unlikely to me," says Shimon Gibson, a noted biblical archaeologist to whom Parfitt has described his project. "You have to make tremendous leaps." Those who hope to find the original biblical item, moreover, will likely reject Parfitt's claim that the best we can do is an understudy. Animating all searches for the Ark is the hope — and fear — that it will retain the unbridled divine power the Old Testament describes. What would such a wonder look like in our postmodern world? What might it do? Parfitt's passionately crafted new theory, like his first, could eventually be proven right. But if so, unlike the fiction in the movies, it would deny us an explosive resolution.