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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.

An Oldie Vies for Nutrient of the Decade

2008-02-24 18:45:22 | Weblog

Vitamin D: An Oldie Vies for Nutrient of the Decade

The so-called sunshine vitamin is poised to become the nutrient of the decade, if a host of recent findings are to be believed. Vitamin D, an essential nutrient found in a limited number of foods, has long been renowned for its role in creating strong bones, which is why it is added to milk.

Now a growing legion of medical researchers have raised strong doubts about the adequacy of currently recommended levels of intake, from birth through the sunset years. The researchers maintain, based on a plethora of studies, that vitamin D levels considered adequate to prevent bone malformations like rickets in children are not optimal to counter a host of serious ailments that are now linked to low vitamin D levels.

To be sure, not all medical experts are convinced of the need for or the desirability of raising the amount of vitamin D people should receive, either through sunlight, foods, supplements or all three. The U.S. government committee that establishes daily recommended levels of nutrients has resisted all efforts to increase vitamin D intake significantly, partly because the members are not convinced of assertions for its health-promoting potential and partly because of time-worn fears of toxicity.

This column will present the facts as currently known, but be forewarned. In the end, you will have to decide for yourself how much of this vital nutrient to consume each and every day and how to obtain it.

Where to Obtain It

Through most of human history, sunlight was the primary source of vitamin D, which is formed in skin exposed to ultraviolet B radiation (the UV light that causes sunburns). Thus, to determine how much vitamin D is needed from food and supplements, take into account factors like skin color, where you live, time of year, time spent out of doors, use of sunscreens and coverups and age.

Sun avoiders and dark-skinned people absorb less UV radiation. People in the northern two-thirds of the country make little or no vitamin D in winter, and older people make less vitamin D in their skin and are less able to convert it into the hormone that the body uses. In addition, babies fed just breast milk consume little vitamin D unless given a supplement.

In addition to fortified drinks like milk, soy milk and some juices, the limited number of vitamin D food sources include oily fish like salmon, mackerel, bluefish, catfish, sardines and tuna, as well as cod liver oil and fish oils. The amount of vitamin D in breakfast cereals is minimal at best. As for supplements, vitamin D is found in prenatal vitamins, multivitamins, calcium-vitamin D combinations and plain vitamin D. Check the label, and select brands that contain vitamin D3, or cholecalciferol. D2, or ergocalciferol, is 25 percent less effective.

Vitamin D content is listed on labels in international units (IU). An eight-ounce glass of milk or fortified orange juice is supposed to contain 100 IU Most brands of multivitamins provide 400 a day. Half a cup of canned red salmon has about 940, and three ounces of cooked catfish about 570.

Myriad Links to Health

Let's start with the least controversial role of vitamin D ― strong bones. Last year, a 15-member team of nutrition experts noted in The American Journal of Clinical Nutrition that "randomized trials using the currently recommended intakes of 400 IU vitamin D a day have shown no appreciable reduction in fracture risk."

"In contrast," the experts continued, "trials using 700 to 800 IU found less fracture incidence, with and without supplemental calcium. This change may result from both improved bone health and reduction in falls due to greater muscle strength."

A Swiss study of women in their 80s found greater leg strength and half as many falls among those who took 800 IU of vitamin D a day for three months along with 1,200 milligrams of calcium, compared with women who took just calcium. Greater strength and better balance have been found in older people with high blood levels of vitamin D.

In animal studies, vitamin D has strikingly reduced tumor growth, and a large number of observational studies in people have linked low vitamin D levels to an increased risk of cancer, including cancers of the breast, rectum, ovary, prostate, stomach, bladder, esophagus, kidney, lung, pancreas and uterus, as well as Hodgkin's lymphoma and multiple myeloma.

Researchers at Creighton University in Omaha conducted a double-blind, randomized, placebo-controlled trial (the most reliable form of clinical research) among 1,179 community-living, healthy postmenopausal women. They reported last year in The American Journal of Clinical Nutrition that over the course of four years, those taking calcium and 1,100 IU of vitamin D3 each day developed about 80 percent fewer cancers than those who took just calcium or a placebo.

Vitamin D seems to dampen an overactive immune system. The incidence of autoimmune diseases like Type 1 diabetes and multiple sclerosis has been linked to low levels of vitamin D. A study published on Dec. 20, 2006, in The Journal of the American Medical Association examined the risk of developing multiple sclerosis among more than seven million military recruits followed for up to 12 years. Among whites, but not blacks or Hispanics, the risk of developing MS increased with ever lower levels of vitamin D in their blood serum before age 20.

A study published in Neurology in 2004 found a 40 percent lower risk of MS in women who took at least 400 IU of vitamin D a day.

Likewise, a study of a national sample of non-Hispanic whites found a 75 percent lower risk of diabetes among those with the highest blood levels of vitamin D.

Vitamin D is a fat-soluble vitamin that when consumed or made in the skin can be stored in body fat. In summer, as little as five minutes of sun a day on unprotected hands and face can replete the body's supply. Any excess can be stored for later use. But for most people during the rest of the year, the body needs dietary help.

Furthermore, the general increase in obesity has introduced a worrisome factor, the tendency for body fat to hold on to vitamin D, thus reducing its overall availability.

As for a maximum safe dose, researchers like Bruce Hollis, a pediatric nutritionist at the Medical University of South Carolina in Charleston, maintain that the current top level of 2,000 IU is based on shaky evidence indeed ― a study of six patients in India. Hollis has been giving pregnant women 4,000 IU a day, and nursing women 6,000, with no adverse effects. Other experts, however, are concerned that high vitamin D levels (above 800 IU) with calcium can raise the risk of kidney stones in susceptible people.

Giant Sheets of Dark Matter Detected

2008-02-23 20:21:29 | Weblog

Giant Sheets of Dark Matter Detected

Cloaked Giants

Cloaked Giants
A dark matter ring is seen in a galaxy center. An international team of astronomers peering into the deep Universe said they had mapped the biggest-ever structure of the enigmatic substance known as dark matter.

The most colossal structures in the universe have been detected by astronomers who tuned into how the structures subtly bend galactic light.

The newfound filaments and sheets of dark matter form a gigantic features stretching across more than 270 million light-years of space--three times larger than any other known structure and 2,000 times the size of our own galaxy.

Because the dark matter, by definition, is invisible to telescopes, the only way to detect it on such grand scales is by surveying huge numbers of distant galaxies and working out how their images, as seen from telescopes, are being weakly tweaked and distorted by any dark matter structures in intervening space.

"We measured the shapes of millions of galaxies and then mapped the stretching of their light," explained astronomer Ludovic Van Waerbeke of the University of British Columbia. The international team from France and Canada studied the galaxies with the Canada-French-Hawaii Telescope Survey's MegaCam telescope in Hawaii.

The resulting map of distorted galaxies reveals the locations of the vast dark matter structures, with more dark matter located where the greatest distortions are seen, he explained. A paper describing the discovery by Van Waerbeke and his colleagues appears in the latest issue of Astronomy and Astrophysics.

The dark matter of the giant structures can distort the appearance of distant galaxies because dark matter has gravity, which can alter the course of light--or "lense" it--as it flies through space. So although the galaxies themselves are not affected, their images are distorted as seen from Earth when their light passes near significant concentrations of dark matter. The distortion is very small, on the order of 0.1 percent.

It's sort of like there were vast strings or sheets of glass prisms out there messing up the images of the galaxies, with more distortion corresponding to a greater number of prisms.

"If we were able to see the dark matter from Earth it would be a very complex network of filaments and sheets," Van Waerbeke told Discovery News.

That sort of cobwebby structure matches computer models which predict that the visible matter in the universe--clusters and super clusters of galaxies--are just the small lights in much vaster clusters of dark matter. All of it is expanding and in some places still connected by filaments of dark matter--rather like very stringy Mozzarella cheese pulled from a hot pizza.

"They're picking up these really large filaments," said astronomer Bhuvnesh Jain of the University of Pennsylvania. The filaments are 10 to a 100 times less dense than the clusters where filaments meet and things like galaxies collect, he explained.

The filaments are of special interest to cosmologists studying the early universe because unlike in the clusters of light and dark matter where things have smashed together a lot, the filaments are relics of much earlier times, said Jain.

"The structures that are providing all this action are still forming," Jain said. The filaments contain regular matter as well, he said, but so little that few stars or galaxies can form – thus far in the history of the universe, anyhow.

Mysterious Haze Found on Venus

2008-02-23 16:26:00 | Weblog

Mysterious Haze Found on Venus

Venus Haze

Venus’s atmosphere, taken by the Venus Monitoring Camera (VMC) during Venus Express orbit number 459 on 24 July 2007. The view shows the southern hemisphere of the planet.

Venus Clouds

Venus’s atmosphere, taken by the Venus Monitoring Camera (VMC) during Venus Express orbit number 465 on 30 July 2007.

Bright hazes that mysteriously appear and then disappear on Venus in a matter of days have revealed a new dynamic feature of the planet's cloudy atmosphere that is unlike anything on Earth.

The European Space Agency's Venus Monitoring Camera (VMC) captured a series of images showing the development of a bright haze over the southern latitudes of the planet in July 2007. Over a period of days, the high-altitude veil continually brightened and dimmed, moving towards equatorial latitudes and then back towards the south pole.

These transient dark and bright markings indicate regions on the cloud-covered world where solar ultraviolet radiation is being absorbed and reflected by sulfuric acid particles, mission scientists said this week.

Gaseous sulfur dioxide and small amounts of water vapor are usually found below altitudes of about 43 miles (70 kilometers) in Venus' carbon-dioxide rich atmosphere. These molecules are usually shrouded from view by cloud layers above that block our view to the surface at visible wavelengths.

ESA scientists think the sulfuric acid particles that make up the bright haze are created when some atmospheric process lifts the gaseous sulfur dioxide and water vapor high up above the cloud tops where they are exposed to ultraviolet radiation from the sun.

The UV radiation breaks up the molecules, making them highly reactive. The fragments of the molecules eagerly seek each other out and combine to form the sulfuric acid particles.

"The process is a bit similar to what happens with urban smog over cities," said mission team member Dmitri Titov of the Max Planck Institute for Solar System Research in Germany.

Exactly what causes the sulfur dioxide and water vapor to well up is not known, but Titov says it is likely some internal process of Venus' atmosphere.

The transient dark markings on the VMC images are even more of a mystery. They are caused by something that absorbs UV radiation, but scientists don't yet know what the chemical is.

Some Women Do Not Have G-Spots

2008-02-23 12:31:19 | Weblog

Small Study Concludes Some Women Do Not Have G-Spots

The debate has raged for some time as to whether or not the fabled G-spot exists.

But one scientist has concluded that the much-talked-about area believed to be the point of origin for the female "vaginal" orgasm does exist but only in some women, according to a small study published in the Journal of Sexual Medicine.

Emmanuele Jannini of the University of L'Aquila in Italy used an ultrasound to scan the area of the vagina where the G-spot, also called the Gräfenberg spot after Ernest Gräfenberg, the man who discovered it, is located.

Jannini determined that the tissue on the front vaginal wall located behind the urethra was noticeably thicker in the women who reported having vaginal orgasms. The thicker tissue, the study concluded, demonstrates the presence of a G-spot.

"For the first time, it is possible to determine by a simple, rapid and inexpensive method if a woman has a G-spot or not," French news agency AFP quoted Jannini as saying. "Women without any visible evidence of a G-spot cannot have a vaginal orgasm."

Click here for more on this story from the Journal of Sexual Medicine.

Did Martian Oceans Bubble From Below?

2008-02-22 20:00:03 | Weblog

Did Martian Oceans Bubble From Below?

Gusev Crater
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Gusev Crater
This image taken in 2005 by the Spirit Rover shows the sunset casting a blue glow above the rim of Gusev Crater on Mars. Fan-shaped deltas at the edge of huge basins scattered across Mars were probably formed by a titanic influx of water, gushing from the bowels of the Red Planet, according to study released.

Fan-shaped deltas at the edge of huge basins scattered across Mars were probably formed by a titanic influx of water, gushing from the bowels of the Red Planet, according to study released Wednesday.

The origin and morphology of the deltas, studded with curious step-like terraces, have perplexed scientists since they were first observed three years ago.

Today the surface of Mars is bone dry, but a growing body of evidence suggests as much as a third of its surface was at one time covered with oceans.

But scientists have differed -- sometimes sharply -- as to exactly where the water came from.

A quartet of researchers at Utrecht University in the Netherlands led by Erin Kraal, using satellite images and topographical data from the Mars Orbiter, hypothesized that these unique formations could only have originated from a single, massive basin-filling event.

Their study, published in Nature, also concluded that the water rushed in over a period measured in tens of years, not millions, as many scientists had thought.

And not just a little bit, either.

"Water volumes would be that of the Mississippi River over the course of 10 years, or the Rhine River flowing for 100 years into a 62-mile-wide basin," said Krall.

Rainfall could not have accounted for so much water over such a short timespan, which means that it must have come from deep within the planet.

Krall's findings bolster research, published last year, suggesting that Mars once had a criss-cross underground water system that may have latticed the entire planet.

Still unexplained, however, were the strange fan-shaped geological formations studded with steps leading into the basin. Were they consistent with the theory of a massive flow of liquid from the planet's interior?

To find out, the researchers refined an experiment that they had first conducted as part of a high school science class.

"There are no fans with steps on Earth, so we had to build one," said Kraal, who is now a geoscience researcher at Virginia Tech University.

The scientists dug a mock crater in a roomful of sand, then simulated water flow into the crater.

As the fan, created by the incoming stream of water, intersected with the rising water level in the basin, steps -- much like the ones observed on Mars -- appeared.

"As the water flows in through a channel, it erodes the sediment," explained Kraal. "The water fans out and deposits the transported sediment as deltas, building steps down into the basin."

Kraal points out that there were likely other sources of water on Mars, and that his theory only explains the dozen or so large basins -- averaging 60 miles across -- with fans seen on satellite images and data collected by a laser altimeter aboard the U.S. orbiter.