Cheap, safe drug (based on vinegar) kills most cancers - Dichloracetate (DCA)

IT SOUNDS almost too good to be true: a cheap and simple drug that kills almost all cancers by switching off their "immortality". The drug, dichloroacetate (DCA), has already been used for years to treat rare metabolic disorders and so is known to be relatively safe. It also has no patent, meaning it could be manufactured for a fraction of the cost of newly developed drugs.

reposted from: New Scientist
my highlights / edits

New Scientist has received an unprecedented amount of interest in this story from readers. If you would like up-to-date information on any plans for clinical trials of DCA in patients with cancer, or would like to donate towards a fund for such trials, please visit the site set up by the University of Alberta and the Alberta Cancer Board. We will also follow events closely and will report any progress as it happens.

Evangelos Michelakis of the University of Alberta in Edmonton, Canada, and his colleagues tested DCA on human cells cultured outside the body and found that it killed lung, breast and brain cancer cells, but not healthy cells. Tumours in rats deliberately infected with human cancer also shrank drastically when they were fed DCA-laced water for several weeks.

DCA attacks a unique feature of cancer cells: the fact that they make their energy throughout the main body of the cell, rather than in distinct organelles called mitochondria. This process, called glycolysis, is inefficient and uses up vast amounts of sugar. Until now it had been assumed that cancer cells used glycolysis because their mitochondria were irreparably damaged. However, Michelakis's experiments prove this is not the case, because DCA reawakened the mitochondria in cancer cells. The cells then withered and died

Full Article: Cancer Cell, DOI: 10.1016/j.ccr.2006.10.020 (pdf)

Michelakis suggests that the switch to glycolysis as an energy source occurs when cells in the middle of an abnormal but benign lump don't get enough oxygen for their mitochondria to work properly (see Diagram). In order to survive, they switch off their mitochondria and start producing energy through glycolysis.

Crucially, though, mitochondria do another job in cells: they activate apoptosis, the process by which abnormal cells self-destruct. When cells switch mitochondria off, they become "immortal", outliving other cells in the tumour and so becoming dominant. Once reawakened by DCA, mitochondria reactivate apoptosis and order the abnormal cells to die.

“Once reawakened by DCA, mitochondria order the abnormal cancer cells in a tumour to die”

"The results are intriguing because they point to a critical role that mitochondria play: they impart a unique trait to cancer cells that can be exploited for cancer therapy," says Dario Altieri, director of the University of Massachusetts Cancer Center in Worcester.

The phenomenon might also explain how secondary cancers form. Glycolysis generates lactic acid, which can break down the collagen matrix holding cells together. This means abnormal cells can be released and float to other parts of the body, where they seed new tumours.

DCA can cause pain, numbness and gait disturbances in some patients, but this may be a price worth paying if it turns out to be effective against all cancers. The next step is to run clinical trials of DCA in people with cancer. These may have to be funded by charities, universities and governments: pharmaceutical companies are unlikely to pay because they can't make money on unpatented medicines. The pay-off is that if DCA does work, it will be easy to manufacture and dirt cheap.

Paul Clarke, a cancer cell biologist at the University of Dundee in the UK, says the findings challenge the current assumption that mutations, not metabolism, spark off cancers. "The question is: which comes first?" he says.

From issue 2587 of New Scientist magazine, 20 January 2007, page 13

More...

• Newsweek 23rd January 2007
  
• The Economist January 2007
• University of Alabama News
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The Calorie Restriction Society - for people trying to live longer by eating fewer calories

Welcome to the Calorie Restriction (CR) Society

Our goal is to help people of all ages live longer and healthier lives simply by:

• eating fewer calories
• maintaining adequate nutrition

Since the 1930's extensive scientific research has shown that calorie restricted (CR) diets improve health and extend lifespans of nearly every species tested, including worms, spiders, rodents, dogs, cows and monkeys. We believe it is likely that people who carefully adopt a CR diet will see similar results.

The CR Society supports the efforts of people who practice CR for future longevity, current health, or other benefits; those curious about or interested in understanding the effects of the diet; and those interested in the development of related, science-based life-extension and health-enhancing technologies. Our mailing lists provide a rich forum for such topical discussions.

Calorie Restriction...the only proven life-extension method known to modern science.

reposted from: http://www.calorierestriction.org/Home
my highlights / emphasis / edits

The Scent of a Calorie: Whiff of Food Cancels Longevity from Caloric Restriction

February 01, 2007 The Scent of a Calorie: Whiff of Food Cancels Longevity from Caloric Restriction Diet-restricted fruit flies start acting like they are eating when they smell nutrients By Nikhil Swaminathan

reposted from: Scientific American
my highlights / emphasis / edits

Image: © STOCKBYTE/CORBIS LIFE-SHORTENING AROMA: In fruit flies, scientists have determined that the smell of food can have a negative effect on caloric restriction diets, generally designed to impart a longer life.

Evidence began mounting as long as 70 years ago that restricting calories while consuming necessary amounts of sustenance could increase one's life span. Since then, a group called the North Carolina-based Calorie Restriction Society has sprouted whose 1,800 members routinely down about half of the daily caloric intake recommended by the Food and Drug Administration (FDA) in the hope of living to the ripe old age of 120.

New research may prompt the organization to send out nose plugs with its next newsletter.

A team of scientists at the Baylor College of Medicine in Houston, New Mexico State University at Las Cruces and the University of Houston found that the average life span of fruit flies on restricted diets decreased when they were exposed to food odors. The findings, according to lead researcher Scott Pletcher of Baylor's Huffington Center on Aging, suggest that the flies are "actually perceiving the environment," thinking they are in a nutrient-rich place and then their bodies are "adaptively responding to it." The results imply there is likely some olfactory component affecting humans on caloric restriction diets as well.

Pletcher's group exposed two lab strains of fruit flies on caloric restriction to smells created by live yeast, an important constituent of the fly's diet. These flies died three to 10 days sooner—a 6 to 18 percent reduction in life span—than flies on the same diet that did not get a whiff of the yeast. Their life spans were further shortened if the flies actually ate the yeast paste.

Pletcher says the smell of yeast only had an effect on the life spans of dieting flies and not on those that were fully fed and likely already perceived their immediate environment to be nutrient-rich. "If you're in what might be considered an alternative physiological state that is associated with long life span under diet restriction, then the foods have some effect," he says, noting "that suggests that there's some interaction because the odorants aren't having the same effect in all environments."

To determine if smell alone has an effect on longevity, Pletcher's team created a fruit fly strain that had a particularly sensitive olfactory receptor inhibited. Fully fed female flies with an impaired sense of smell exhibited an average life span increase of 56 percent compared with unaltered wild females. Males also lived longer than their wild counterparts. Pletcher says this indicates that odor-mediated aging and dietary effects on aging probably share some of the same physiological pathways.

Brown University ecologist Marc Tatar says the current study, published in this week's Science, provides "really profound evidence" that longevity is controlled not by actual resources but rather by hormones that are cued to resources (such as the way plants sense winter by sunlight changes). "It's like the whole system doesn't actually function on the currency of resources anymore, it all functions on virtual data about what the resources should be like," he says. "It's mind over matter."

Pletcher agrees with that analysis, at least in part. "Some component is due to perception," he says, "and another large component is actually consumption." But given the effect that eating versus smelling yeast had on longevity, he says, "Overall, I would guess consumption has a bigger effect than perception, that's for sure."

RELATED LINKS: Being Cool Could Be the Key to a Longer Life Caloric Restriction and Aging How Low-Cal Diet Lengthens Fruit Fly Life Span Benefits of Diet Can Kick in Late in Life

New particle accelerator could rule out string theory

• 22:04 01 February 2007
• NewScientist.com news service
• David Shiga

String theory could be ruled out by experiments at the Large Hadron Collider (LHC), a particle accelerator scheduled to open by the end of 2007, a new study says. The finding offers a new approach for testing this potential "theory of everything", a goal that has so far proven elusive.

reposted from: New Scientist
my highlights / emphasis / edits

According to string theory, particles like electrons and photons are actually tiny, vibrating strings. The beauty of the theory is that it accounts for all of the known forces – including gravity, which the standard model of physics does not. But its critics have complained that there is essentially no way to test it.

Strong evidence for string theory could come from the observation of short-lived, mini black holes at the LHC (see Watching God play dice: The Large Hadron Collider). But the chance of them appearing is extremely small, so a failure to see them would not be a death blow for the theory.

In 2006, string theorist Allan Adams of MIT in Cambridge, US, and others offered a more promising check. They showed that some particle collisions could reveal whether certain fundamental assumptions underlying string theory are wrong.

Now, another team has shown that the energies needed to reveal such effects are achievable at the LHC, which is being built in Geneva, Switzerland. The team was led by Jacques Distler of the University of Texas in Austin, US.

High energies

One of string theory's assumptions comes from Einstein's theory of relativity – that the speed of light is the same for all observers, a principle called Lorentz invariance.

This principle – and three others underlying string theory – determine how strongly particles called W bosons, which transmit the weak nuclear force, interact.

If these interactions are below the strength calculated by Distler's team, it would signal that one of the assumptions built into string theory is incorrect and that therefore string theory itself is wrong, the researchers say.

"They did a very important thing," Adams told New Scientist.

Quantised space

If string theory does seem to be ruled out, physicists will have to find another theory of everything that can explain the LHC observations. "If we see these violations, people will start working very feverishly on some sort of alternative that will produce these violations," Distler told New Scientist.

That alternative may turn out to be a theory called loop quantum gravity, which posits that space itself is quantised into tiny chunks. Some physicists argue that loop quantum gravity does not satisfy Lorentz invariance. "So that's one possible direction people might go," Distler says.

Although the test could in principle rule out string theory if violations are found, both Distler and Adams suspect that the results will turn out to respect the four assumptions, leaving string theory as a viable candidate for the theory of everything.

Quantum World - Learn more about a weird world in our comprehensive special report.

Journal reference: Physical Review Letters (in press)

Breathing life into artificial organs

• 01 February 2007
• From New Scientist Print Edition. Subscribe and get 4 free issues
• Celeste Biever

Jeff Borenstein holds up a piece of semi-transparent rubber, about half the size of a credit card. If all goes to plan this unassuming piece of rubber could become the building block for the first 3D artificial organs.

reposted from: New Scientist
my highlights / edits

Stacks of these bendy, biodegradable flaps are fused together to form structures snaked through with a network of interconnecting channels. When pumped with a solution of cells, nutrients and oxygen, these channels spring into life, forming a system of blood vessels and tissue that might one day be the basis of an artificial heart, kidney or liver.

Borenstein, a micro-machinist at the Draper Laboratory in Cambridge, Massachusetts, is just one of a number of people who are attempting to build sophisticated artificial organs complete with their own network of blood vessels, or vasculature.

So far simple organs including skin and bladders have been built by seeding a tissue scaffold with cells that are cultured in a nutrient-rich broth. Skin and bladder tissue is thin enough for oxygen and nutrients from the broth to reach all the cells, and a dedicated vascular system is unnecessary until the organs are transplanted when the body's own blood vessels take over.

But thicker organs such as the liver, heart and kidneys will need a vascular system while they grow in the lab, otherwise cells beneath the surface will die from lack of oxygen. "The major limiting factor for solid organs right now is vascularity," says Anthony Atala, a tissue engineer at Wake Forest University in Winston-Salem, North Carolina, who last year implanted the first lab-grown bladders in humans (New Scientist, 8 April 2006, p 10).

"The major limiting factor for solid organs right now is a vascular system"

Borenstein's solution is to create a temporary scaffold of biodegradable polymer containing a network of channels, some of which become organ tissue and others blood vessels. The two sets of channels are linked via small pores, allowing nutrients and oxygen pumped through the blood vessels to reach the liver or heart tissue. "Channels help you to establish the organ and maintain function," he says. When the organ is implanted, these channels would be connected to the recipient's own blood vessels.

To create the channels, which are around 10 micrometres in diameter, Borenstein uses a process called soft lithography. A piece of silicon is etched as if to create a reverse cast of the channels, so when the biodegradable material is poured onto the "mould" and removed it has the desired shape. Two halves are fused together and then connected to other copies to create a network of channels (see picture).

So far Borenstein has created 8-centimetre cubes from a range of biodegradable materials, including dissolved spider silk and a polymer called polyglycerol-sebacate, or "biorubber". He can tune the scaffold to the needs of particular organs by using materials with different properties. For instance, cells that take a long time to grow will need a scaffold that degrades slowly after implantation and retains its structure, while others might require a structure that dissolves quickly.

To turn some channels into blood vessels Borenstein lines them with endothelial cells; for liver organ tissue he fills channels with liver cells called hepatocytes. He has also built 2-millimetre-sized hybrid cubes, seeded with both cell types, which filter blood in a similar way to the liver. The blood travels along a "vessel" lined with a single layer of endothelial cells, and passes through the pores into a layer of hepatocytes. These filter the blood and return it to the original vessel.

However, while building a simple cube of cell-lined channels is relatively straightforward, ensuring cells migrate throughout an entire organ so that they fill gaps between these channels may prove more difficult. "This is particularly critical for cells that don't divide or migrate readily like hepatocytes," says Sangeeta Bhatia, a tissue engineer at the Massachusetts Institute of Technology.

Bhatia is pursuing a different approach. Instead of flowing cells through a ready-made structure, she mixes liver cells with a light-sensitive polymer called polyethylene glycol, which she deposits on a surface and covers with a mask. She can build very precise structures by shining light onto the cell-filled polymer to harden those areas not covered by the mask and then washing the rest away (New Scientist, 4 January 2003, p 19). "We build living tissues with light rather than fabricating a scaffold and then occupying it with cells," Bhatia says. "This allows us to embed cells throughout the organ without coaxing the cells to migrate."

She has already used the technique to create liver tissue a few millimetres thick, a breakthrough that will appear in the Journal of the Federation of American Societies for Experimental Biology (FASEB). Although she did not build an entire vascular system to feed the tissue, she did create a network of channel-like voids - 50 micrometres wide - between the liver cells, through which she pumped a fluid rich in oxygen and nutrients. This kept the tissue alive for 10 days. "If we organised these voids into a branching network explicitly, it would look like a vascular system," she says.

Some researchers, however, doubt whether either technique will ever produce structures as intricate as those in the human body, where arteries and veins branch hundreds of times until they form tiny structures just 10 micrometres wide. "They could build such a branching structure but this is very complicated, so I have strong reservations," says Gabor Forgacs at the University of Missouri-Columbia. Forgacs believes that engineering the thicker vessels but leaving the smaller ones to develop on their own might prove more successful.

A group lead by Jens Kelm and Martin Fussenegger of the Swiss Federal Institute of Technology in Zurich has shown that cells can build their own vasculature. Last year they created balls of a mixture of animal and human heart cells and coated them with human umbilical vein endothelial cells. They found that as the heart cells on the inside ran short of oxygen, they released a chemical called VEGF that prompted the endothelial cells to migrate to the centre of the ball and form a network of cells resembling capillaries. When they attached a tissue made of multiple balls to a chicken embryo, the embryo blood vessels fused with those in the grafted tissue, showing that a vasculature formed like this could one day be hooked up to the human body.

But Forgacs believes it would not be possible for an entire heart to form in this way, as they are far too complex. Instead he hopes to combine this approach with a bioprinting technique he has developed. He uses a centrifuge to form clumps of cells, which are printed layer by layer onto a biodegradable gel to build 3D structures (New Scientist, 13 April 2006, p 19). He plans to print large tubes of cells to build veins and arteries, and he hopes the smaller vessels will form by themselves from clumps of heart or liver cells coated in endothelial cells in the space surrounding the larger vessels. Indeed, many of the new techniques being developed are likely to merge as more is learned about how to create the complex networks of cells needed to form hearts, livers and kidneys.

"It's a really exciting time because we are all learning the principles," says David Kaplan at Tufts University in Medford, Massachusetts. "If we can succeed, the impact on human health is immense."

From issue 2589 of New Scientist magazine, 01 February 2007, page 24-25

Brights Calendar 2007

Brights have in common a naturalistic worldview, free of supernaturalism. The photos and quotes included are meant to show just how awesome our universe is. The various events marked in this calendar have been chosen by individual Brights. They represent a spectrum of achievements selected to remember that humanity has always been striving forward, trying to improve both ourselves and our environment.

Check out The Brights' Net site at www.the-brights.net.

What is a bright?

• A bright is a person who has a naturalistic worldview
• A bright's worldview is free of supernatural and mystical elements
• The ethics and actions of a bright are based on a naturalistic worldview

Is Your Worldview Naturalistic?

Think about your own worldview to decide if it is free of supernatural or mystical deities, forces, and entities. If you decide that you fit the description above, then you are, by definition, a bright!

On this website, you can simply say so and, by doing so, join with other brights from all over the world.

Reason and Purpose

Currently the naturalistic worldview is insufficiently expressed within most cultures, even politically/socially repressed. To be a Bright (someone who fits the definition and registers on this Web site) is to participate in a movement to address the situation.

There is a great diversity of persons who have a naturalistic worldview (free of supernatural and mystical elements). Some are members of existing organizations that foster a supernatural-free perspective. Far more individuals are not associated with any formal group or label. Under the broad umbrella of the naturalistic worldview, the constituency of Brights can undertake social and civic actions designed to influence a society otherwise permeated with supernaturalism.

The movement's three major aims are:

1. Promote the civic understanding and acknowledgment of the naturalistic worldview, which is free of supernatural and mystical elements.
2. Gain public recognition that persons who hold such a worldview can bring principled actions to bear on matters of civic importance.
3. Educate society toward accepting the full and equitable civic participation of all such individuals.

This website of The Brights’ Network registers brights into an Internet constituency of Brights and serves as a communications hub for actions that align with the aims and principles of the Brights movement.

US climate scientists pressured on climate change

US scientists were pressured to tailor their reports on global warming to fit the Bush administration's climate change scepticism, a congressional committee heard on Tuesday 30 January. In some cases, this occurred at the request of a former oil-industry lobbyist.

"High-quality science [is] struggling to get out," Francesca Grifo, of the watchdog group Union of Concerned Scientists, told members of the House Oversight and Government Reform Committee. A UCS survey found that 150 climate scientists personally experienced political interference in the past five years in a total of at least 435 incidents.

reposted from: New Scientist
my highlights / emphasis / edits

"Nearly half of all respondents perceived or personally experienced pressure to eliminate the words 'climate change', 'global warming' or other similar terms from a variety of communications," Grifo said.

Rick Piltz, a former US government scientist, told the committee that former White House official Phil Cooney took an active role in casting doubt on the consequences of global climate change. Piltz said he resigned in 2005 as a result of pressure to soft-pedal findings on global warming.

Cooney, who was a lobbyist for the American Petroleum Institute before becoming chief of staff at the White House Council on Environmental Quality, also resigned in 2005. He went on to work for oil giant ExxonMobil, which was recently accused of spending $16 million on supporting climate sceptics.

"Speculative musing"

Documents on global climate change required Cooney's review and approval, Piltz said, adding that "If you know what you are writing has to go through a White House clearance before it is to be published, […] an anticipatory kind of self-censorship sets in."

He added: "[Cooney's] edits of programme reports, which had been drafted and approved by career science programme managers, had the cumulative effect of adding an enhanced sense of scientific uncertainty about global warming and minimising its likely consequences."

According to The Guardian newspaper, Piltz described how Cooney had personally edited out a key section of an Environmental Protection Agency report to Congress on the dangers of climate change, calling it "speculative musing".

Seeking answers

Henry Waxman, a California Democrat who chairs the oversight committee, complained that the White House has balked at supplying documents requested over six months to investigate these allegations.

"The committee isn't trying to obtain state secrets or documents that could affect our immediate national security," Waxman said. "We are simply seeking answers to whether the White House's political staff is inappropriately censoring impartial government scientists."

Kristen Hellmer, of the Council on Environmental Quality, part of the Executive Office of the US President, said the CEQ had been cooperating with Congress. When asked about allegations of political interference in scientific documents, she said: "We do have in place a very transparent system in science reporting."

Spate of accusations

Reporting on the hearing, the New York Times says that even Republicans had little good to say of the Bush administration's handling of climate change science. Almost all the Republicans on the panel began by stating that global warming was happening and that greenhouse gases from human activities were largely to blame.

The Bush administration has suffered a spate of accusations of muzzling climate scientists in recent years. In January 2006, James Hansen, director of the US space agency's Goddard Institute for Space Studies, said that officials at NASA headquarters had ordered their staff to review his lectures, papers, postings on the Goddard website and requests for media interviews (see Top climatologist accuses US of trying to gag him).

In February 2006, the topic was brought up in the House Committee on Science, and New Scientist reported that scientists at another government agency, the National Oceanic and Atmospheric Administration, were also upset about the situation.

The UCS issued its first accusations in February 2004, followed closely by more finger pointing in July of that year.

Mandatory limits

President George W Bush's position on global warming has evolved over his presidency, from open scepticism about the reality of the phenomenon to acknowledgment at a global summit in 2006 that climate change is occurring and that human activities speed it up.

In his 2007 State of the Union address, Bush called climate change "a serious challenge" that should be addressed by technology and greater use of alternative sources of energy. But he stopped short of calling for mandatory limits on US emissions of carbon dioxide, a greenhouse gas blamed in part for global warming.

The congressional discussions come in the run-up to the release of a major United Nations report on climate change, scheduled for Friday in Paris, France.

Leaked drafts of the report suggest it will state that "there is a 90% chance humans are responsible for climate change", mostly due to the burning of fossil fuels. That contrasts with the last version of the Intergovernmental Panel on Climate Change's report, issued in 2001, which concluded there was a 66% chance that humans were responsible for rising temperatures.

Retailers to stop trans-fat use

Some margarines contain trans-fats

Major UK retailers plan to stop adding harmful trans-fats to their own-brand products by the end of the year. Trans fats at Wikipedia.

The move was announced by British Retail Consortium members Asda, Boots, Co-op, Iceland, Marks and Spencer, Sainsbury's, Tesco and Waitrose.

It is hoped the move could help cut rates of heart disease and obesity.

reposted from: http://news.bbc.co.uk/1/hi/health/6314753.stm
my highlights / edits

Cholesterol-raising trans-fats, in the form of hydrogenated oils, are often added to bakery and dairy products to extend shelf-life and improve texture.

TRANS-FATS They are partially hydrogenated vegetable oils, turning oily foods into semi-solid foods Used to extend shelf life of products Put into pastries, cakes, margarine and some fast foods Can raise levels of "bad" cholesterol Even a small reduction in consumption can cut heart disease They have no nutritional benefit

They are also used by the fast-food industry.

But they have no nutritional value, and like saturated fats, they raise blood cholesterol levels which increase the risk of coronary heart disease.

Health authorities around the world have recommended their consumption be slashed.

A BRC spokesman said about 5,000 own-brand products would be affected by the decision.

'Major change'

He said it took time to remove the fats, as retailers had to ensure their products remained appealing to consumers in their re-formulated form.

Several leading retailers have already committed to reducing trans-fat levels, but the latest announcement represents a marked acceleration of the process.

Andrew Opie, BRC food policy director, said the decision by its leading members showed that they were prepared to act to achieve major change must faster than any legislation could do.

He said: "This is the latest in a string of healthy food initiatives and shows that BRC members, responding to customer concerns, are willingly delivering a scale and pace of change way beyond anything retailers or manufacturers are doing anywhere else in Europe."

Alex Callaghan, of the British Heart Foundation, said: "It's good to see companies making moves towards reducing and removing trans-fats from their own-brand products.

"Currently, it isn't easy for shoppers to know how much trans-fats are in the food they eat, and it can be confusing.

"The BHF calls for manufacturers and retailers to work towards elimination of trans-fats from products.

"In the meantime, trans-fats should be clearly labelled food packaging so that people can make informed decisions about their diet."

In Denmark, trans-fats in the form of partially hydrogenated oils were effectively banned four years ago.

The European Union is encouraging retailers to reduce or stop adding trans-fats.

However, it is also taking action against the Danish authorities, on the grounds that their ban is a block on free trade with other member states.

Chemically, trans fats are made of the same building blocks as non-trans fats, but have a different shape. In trans fat molecules, the double bonds between carbon atoms (characteristic of all unsaturated fats) are in the trans rather than the cis configuration, resulting in a straighter, rather than a kinked shape. As a result, trans fats are less fluid and have a higher melting point than the corresponding cis fats. (source: Wikipedia)

Basic Concepts: Arguements

As my first contribution to the growing list of basic terms and concepts, I'm going to explain a few things no one asked about when I opened the request line. But, these are ideas that are crucial building blocks for things people actually did ask about, like falsifiability and critical thinking, so there will be a payoff here.

reposted from: Adventures in Ethics & Science
my highlights / edits

Philosophers talk a lot about arguments. What do they mean?

An argument is a set of claims. One of those claims is the conclusion which the other claims are supposed to support. While logicians, geometers, and that crowd customarily give you the conclusion as the last claim in the argument, arguments in novels and op-ed pieces may give you the conclusion at the very start of the argument.

The non-conclusion claims in the argument are generally referred to as premises or assumptions. These claims are the reasons being offered to support the conclusion of the argument. Note that some of the claims labeled as "assumptions" feel like certainties.

The point of an argument is to give good reasons for accepting the conclusion. An argument is something stronger and more persuasive than a mere opinion. What makes an argument more persuasive is that it makes its assumptions clear and then shows how these assumptions lead logically to the conclusion.

A valid argument is one where the truth of the premises guarantees the truth of the conclusion. In other words, if your argument is valid, someone who accepts your premises as true will have to accept your conclusion or else embrace a logical contradiction.

Do you like Ps and Qs (and upside down As and backward Es)? If so, you'll find a wide selection of symbolic logic textbooks that set out a dizzying array of valid patterns of inference. Many philosophers manage to set out arguments without talking in Ps and Qs and upside down As and backward Es, though. There are some patterns of inference that careful thinkers will recognize as valid (even if they can't whip out the old school name of the syllogism) and others that they will recognize as not guaranteeing a true conclusion even if the premises are true.

Here's an example of an invalid argument:

1. If my battery is dead, my car won't start. (premise)
2. My car won't start. (premise)
3. Thus, my battery must be dead. (conclusion)

It's perfectly possible for both premises to be true, yet for the conclusion to be false (because something else is wrong with my car that is keeping it from starting). In other words, we shouldn't take (1) and (2) as sufficient reasons for accepting (3).

Here's an example of a valid argument:

1. Britney Spears is from Mars. (premise)
2. Martians have astounding vocal range and are great dancers. (premise)
3. Hence, Britney Spears has astounding vocal range and is a great dancer. (conclusion)

If claims (1) and (2) were true here, there is no way that claim (3) could fail to be true. Accepting the assumptions commits you to the conclusion -- unless, of course, you choose to opt out of the shared rules of valid inference we've been trained to accept. That's always an option, but it's not one that puts you in a very good place to engage with others who accept those rules (which is something you'd want to do to persuade them to accept some of your conclusions)!

Valid or not, most of you are not accepting my argument's conclusion, that Britney Spears has astounding vocal range and is a great dancer. Why not? Perhaps because you reject my premise that Britney Spears is from Mars and/or my premise that Martians have astounding vocal range and are great dancers. Even if the logical connections between my premises and my conclusion are good, if any of my assumptions are false, you're entitled to reject my argument as giving good reasons to believe the conclusion. (By the way, even people who accept the truth of the claim that Britney Spears has astounding vocal range and is a great dancer will reject the argument offered here in favor of that conclusion -- they won't want to endorse the false premises about Martians.)

An argument that is valid and whose premises are true is a sound argument. Not only does it have the right kind of logical connections between the conclusion and the reasons offered to support the conclusion, but all those reasons are true claims. The challenge, of course, is in being sure of the truth of your premises. "All men are mortal" sure sounds like a true claim, but given that there are scads of people who haven't yet demonstrated their mortality by kicking off, can we be certain that one of them won't turn out to be immortal?

Don't go whipping out data on all the humans who have dies so far, thus proving themselves to be mortal and making it a good bet that we are all mortal, too. The argument:

1. Guy 1 died.
2. Guy 2 died.
3. Guy 3 died.
4. Guy 4 died.
5. Guy 5 died. ...

Thus, we're all going to die eventually.

looks like an appealing argument, but it is not a valid argument -- at least, there's no guarantee that the truth of the conclusion follows from the truth of the premises. Rather than being a deductive argument, it's an inductive argument.

Inductive inference can be plenty useful, but as any broker -- or any kid who plays a lot of Duck Duck Goose -- will tell you, there is a real danger in inferring future outcomes from past performance. More about this when we take up "falsifiability".

Human metabolism recreated in lab

Scientists can use the virtual model instead of working on real cells

US researchers say they have created a "virtual" model of all the biochemical reactions that occur in human cells.

They hope the computer model will allow scientists to tinker with metabolic processes to find new treatments for conditions such as high cholesterol.

It could also be used to individually tailor diet for weight control, the University of California team claimed.

Their development is reported in the journal, Proceedings of the National Academy of Sciences.

A team of six bioengineering researchers at the University of California analysed the human genome to see what genes corresponded to metabolic processes, such as those responsible for the production of enzymes.

They spent a year manually going through 1,500 books, review papers and scientific reports from the past 50 years before constructing a database of 3,300 metabolic reactions.

The information was then used to create a network of metabolic processes in the cell, similar to a traffic network.

You could make a metabolic model for an individual person which is a tantalising prospect Professor Bernhard Palsson

Study leader Professor Bernhard Palsson said the network could be used to see what would happen if a drug was used to target a specific metabolic reaction, such as the synthesis of cholesterol.

Or it could be used to predict what would happen if you interfere with a metabolic reaction in a specific type of cell, such as a blood or heart cell.

And eventually it could even be used to create an individual network for a person.

"The new tool we've created allows scientists to tinker with a virtual metabolic system in ways that were, until now, impossible, and to test the modelling predictions in real cells," said Mr Palsson, who is professor of bioengineering and medicine.

"You can take a drug target and you can make the flow through that reaction more and more restrictive or you can calculate all the reactions that you have to go through to make a certain product."

Metabolism

Metabolic reactions in cells include those which convert food sources, such as fats, protein and carbohydrate into energy and to make other molecules used by the body.

There are hundreds of human disorders which are a result of problems with metabolism.

One example is haemolytic anaemia, a condition where red blood cells are broken down too rapidly.

To test the computer model, the team ran 288 different simulations, such as the synthesis of hormones, testosterone and oestrogen, and the metabolism of fat from the diet.

"We all have natural variation in the capacity of these pathways, for example in our ability to make cholesterol, so you could make a metabolic model for an individual person which is a tantalising prospect."

Keith Frayn, professor of human metabolism at the University of Oxford, said the model would allow scientists to spot potential problems with targeting certain reactions early on in their research.

"It's increasingly recognised there are these networks of metabolism and we need to know if we target something how that will spread out and this is potentially a way of dealing with that."

Dr Anthony Wierzbicki, consultant in specialist laboratory medicine at St Thomas's hospital, has done a lot of work on the role of cholesterol in heart disease.

"This is a potentially interesting tool for investigating metabolism of which cholesterol biochemistry forms a part," he said.

But he added that the model would have to be "sophisticated" enough to predict what happens in the production and breakdown of cholesterol as well how it is absorbed from the gut as the two were closely linked.

reposted from: http://news.bbc.co.uk/1/hi/health/6310075.stm
my highlights / edits

Climate Change - UK temperatures to 2080

World's largest climate change experiment.

UK temperature change

How will the UK’s temperature change over the course of this century?

Compare average temperatures for summer, winter, spring and autumn around the UK.

Watch hypothetical weather forecasts from 2020, 2050 and 2080.

Find out how changes in temperature will affect you.

reposted from: BBC
my highlights / edits

12 Books that changed the world by Melvyn Bragg

Introduction

Begins Sunday 28th Jan at 5.45pm on ITV1 When people think of things that have changed the world, they tend to think of events – natural disasters, assassinations, wars and scientific breakthroughs. What tends to get overlooked is the powerful, transforming ideas that are communicated in the apparently unassuming pages of books. 12 Books That Changed The World is presented, written and edited by Melvyn Bragg. In this series we look at 12 of the most exciting and powerful books ever written in the English language, all penned by British authors, without which the world would be a very different place. The result is a fascinating celebration of the power of the printed word. The 12 books Every week, Melvyn Bragg reveals the names of three of the most significant books of all time. Episode One Principia Mathematica, Sir Isaac Newton (1687) Married Love, Marie Stopes (1918) The First Rule Book of the Football Association (1863) Episode Two The Origin of Species, Charles Darwin (1859) A Vindication of the Rights of Woman, Mary Wollstonecraft (1792) Speech to the House of Commons, William Wilberforce (12th May 1789) Episode Three The Wealth of Nations, Adam Smith (1776) The King James Bible (1611) Magna Carta (1215) Episode Four Experimental Research in Electricity, Michael Faraday (1855) Patent Specification for Arkwright's Spinning Machine (1769) William Shakespeare's First Folio (1623)

Introduction to Windows Vista

Personal Computer World review.

Analyst dismisses Second Life as a 'pyramid scheme'

An article claiming that the economic system in Second Life is a "pyramid selling scheme" has created a furore of debate about the way business is conducted in the virtual community.

The article was written by financial analyst Randolph Harrison and published in the Capitalism 2.0 blog.

Harrison claims in the article that the economic system in Second Life has become a " Ponzi scheme" that promises monetary gains for everyone, but ultimately benefits only a select few.

The analyst said that cons and cheats in monetary deals are rampant, that virtual banks routinely spring up and disappear over night, and that Second Life 'residents' are quick to take each others' money and run.

Harrison claimed that the markets in the game, in which people exchange virtual 'Linden Dollars' for real-life money, is "virtually rigged" to yield the least amount of money to players looking to cash in their virtual currency.

"Second Life is not a dramatic taste of our future in which markets are virtual, currency is free from government control, taxes are non-existent, and normal people can become real millionaires simply by clicking their mouse a few times," he said.

"Second Life is a classic pyramid scheme. Or, more of an Amway-like pyramid: partially legitimate, partially Ponzi."

Harrison acknowledged that the system works fine for recreational users who visit the online world strictly for entertainment.

But the claim that Second Life is an emerging economy ripe for the picking by everyday people turned entrepreneurs is, by and large, a scam, according to the analyst.

Supporters and residents of Second Life were quick to criticise Harrison's article. Blogger Tateru Nino suggested that the assertion was like comparing "Buicks to boysenberries".

"There are truths in there certainly, but very deceptively phrased ones, and chunks of the material are apparently no longer current or accurate," said Nino.

Nino claimed that Harrison's observations on the exchange market were not based on Second Life creator Linden Lab's own Lindex exchange system, but on smaller private exchange markets operated by users.

The rates in Harrison's exchange study were inflated because such a large amount of money was being traded, artificially creating a low rate, according to Nino.

"By his own figures, Harrison tried to cash out more than three per cent of the then total currency in motion at once, and was distressed when supply and demand worked the way supply and demand does," he wrote.

John Zdanowski, chief financial officer at Linden Lab, told vnunet.com that the Lindex exchange system is not wholly dependent on supply and demand.

"While the exchange is based on a floating rate, Linden Lab maintains some indirect means with which to maintain price stability, including control over the stipend that is offered to users and the pricing of various Linden Dollar 'sinks'," he said.

Linden Dollar 'sinks' are the price of uploading images, for example, or posting classified ads.

Wagner James Au has worked as an 'embedded' journalist in Second Life since 2003, and currently runs the New World Notes blog which chronicles the virtual community.

Au told vnunet.com that users looking to "get rich quick" in Second Life will, like their real-world counterparts, often fall victim to con artists and scams.

"If you are looking for a quick buck you are probably going to lose your money," said Au. "The people who are successful, in my observations, are the ones who establish themselves, build a trust network and build their businesses. "

The revelation of a grand scheme being run by wealthy users to con new residents out of their money is an extremely rare occurrence, according to Au.

"What will happen is you have someone who started out and something will happen; they will run out of time in their real life or they will get annoyed with the people they are working with and leave," he said.

Among those who invest substantial amounts of time and money, however, a merchant's reputation can make or break a Second Life business.

"What [Harrison] is missing is the day-to-day in-world social activity," said Au, noting that residents have even gone so far as to establish a Second Life chamber of commerce.

"There is this tight social network of content creators who are watching after each other," he said.

Au explained that most users will spend several months in the Second Life community before attempting to establish a business.

At that point, he said, players have grown much more savvy to the way the market works, and the amount of time and currency invested in the virtual business makes users less likely to try and cash out all their Linden Dollars at once and experiencing the sort of inflation noted by Harrison.

"For the serious content developers, it is in their interest not to take out a lot of money at once," Au said. "What the most successful people do is take out their money slowly."

reposted from: vnunet.com
my highlights / edits

Basics: Logic, aka "It's illogical to call Mr. Spock logical"

This is another great basics topic, and it's also one of my pet peeves. In general, I'm a big science fiction fan, and I grew up in a house where every saturday at 6pm, we all gathered in front of the TV to watch Star Trek. But one thing which Star Trek contributed to our vocabulary, for which I will never forgive Gene Rodenberry, is "Logic". As in, Mr. Spock saying "But that would not be logical.".

The reason that this bugs me so much is because it's taught a huge number of people that "logical" means the same thing as "reasonable". Almost every time I hear anyone say that something is logical, they don't mean that it's logical - in fact, they mean something almost exactly opposite - that it seems correct based on intuition and common sense.

If you're being strict about the definition, then saying that something is logical by itself is an almost meaningless statement. Because what it means for some statement to be "logical" is really that that statement is inferable from a set of axioms in some formal reasoning system. If you don't know what formal system, and you don't know what axioms, then the statement that something is logical is absolutely meaningless. And even if you do know what system and what axioms you're talking about, the things that people often call "logical" are not things that are actually inferable from the axioms.

Logic, in the sense that we generally talk about it, isn't really one thing. Logic is a name for the general family of formal proof systems with inference rules. There are many logics, and a statement that is a valid inference (is logical) in one system may not be valid in another. To give you a very simple example, most people are familiar with the fact that in logic, if you have a statement "A", then either the statement "A or not A" must be true. In the most common simple logic, called propositional logic, that's a tautology - that is, a statement which is always true by definition. But in another common and useful logic - intuitionistic logic - "A or not A" is not necessarily true. You cannot infer anything about whether it's true or false without proving whether A is true or false.

More....

So when someone says, a la Mr. Spock, that something is logical, the correct thing to do is to whack them in the head with a logic textbook for saying something nonsensical.

reposted from: http://scienceblogs.com/goodmath/2007/01/basics_logic_aka_its_illogical_1.php
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How Intel shrank processors to 45nm without taking a leak

Pictured left is a die shot of one of Intel's new 45nm Penryn processors, which the company claims represent the biggest breakthough since the sixties. Its development forced Intel to address one of the biggest problems of miniaturisation: leakage current.

A standard transistor of the type used in processors consists of source and drain electrodes sitting in a silicon substrate with a tiny gap between them. Above this gap is a thin layer of insulator, or dielectric; and sitting on that is the gate electrode (click image at right for pop-up diagram). Toggling the voltage at the gate toggles the charge distribution across the gap, and thus its ability to pass current.

This solid-state switch is never quite perfect because there are tiny current flows even in the off state. Most important is the "leakage" across the insulating layer under the gate. This layer is made of silicon dioxide (SiO2) in current designs and when it becomes only a few atoms thick, as it does as processor transistors get smaller, leakage becomes prohibitively high.

So why not have thicker insulation? The problem is that the thinner the layer, the higher is the capacitance of the structure - the amount of charge it can hold. The higher the capacitance, the better the current flow in the on state, and the faster the switching. In other words if you thicken the insulation to reduce leakage, you slow the transistor down.

What Intel has done is to replace the SiO2 with a 'high K dielectric', based on the element Hafnium, which allows a thicker (and thus less leaky) layer of insulation without reducing the capacitance.

Intel has also replaced the usual silicon gate with what it vaguely refers to as a mix of metals. Kaizad Mistry, product manager for Intel's 45nm logic technology development, said Intel was keeping this secret as the precise proportions of these and hafnium are critical.

The overall effect is to boost current flow in the on state, providing fast switching, and cutting leakage in the off state.

Intel claims that relative to 65nm technology the Penryn chips will pack twice as many transistors in a given area, with a 30 percent reduction in switching power, 20 percent faster switching, and a tenfold reduction in leakage across the gate dielectric. It also claims a fivefold reduction in current leaking between the source and drain.

reposted from: http://labs.pcw.co.uk/2007/01/how_intel_shran.html

my highlights / edits

Doggy treadmill gets your pup in shape

For those of you out there whipping your offspring into shape by utilizing the Step2Play middleman, and burning your own fair share of calories on the GameRunner, it's about time Rover joined the fray, eh? The Dog Walker treadmill helps prevent doggy obesity and apparently relieves the dog's stress, all while helping it to exert all that pent-up energy from being cramped up in the house all day. Aside from sporting a smaller, dog-friendly design, casters to enable easy transport, and two side shields to prevent minor tumbling disasters, the machine also sports a safety leash which prevents the pup from sliding off the rear (or giving up on the goal) and a devilish remote control to vary the speed from 0 to 5-kilometers per hour (3.1 mph). So if you're tired of Fido's stomach dragging the ground while crawling around in misery, you can pick up its very own treadmill (to go along with that recently-purchased pedometer) for ¥15,800 ($131).

reposted from: Engadget
my highlights / edits

Intel shows off next generation transistors

Computers the world over are about to get a makeover. Intel, the world's largest computer chip maker, announced on Saturday that its next generation transistors will have metal - not silicon - gate electrodes. They will also have insulating walls made of a "high-K" hafnium (wikipedia) compound, which is transparent to electric fields, instead of silicon dioxide.

reposted from: NewScientist.com news service
my highlights / edits

The changes mean that the 45-nanometre transistors on Intel's next suite of computer processors will not only be faster and smaller than today's 65-nanometre ones, they will also be more power efficient. That combination has been difficult to achieve in the past.

"The implementation of high-k and metal materials marks the biggest change in transistor technology since the introduction of polysilicon gate transistors in the late 1960s," says Intel co-founder Gordon Moore.

The new transistors will make their way into Intel's next generation products, currently codenamed "Penryn", which include the Core 2 Duo, Core 2 Quad and Xeon processors. These will run Windows Vista, Mac OS X, Windows XP and Linux.

Leaky materials

Intel first announced that it would start using the new materials at the end of 2003 (see Intel claims plug for leaky chips). But on Saturday it announced that manufacturing will begin later in 2007, with the first products available in 2008.

"It's no longer a research project, it's real," says Dan Hutcheson, an analyst with VLSI Research in California, US. "This is a really big breakthrough."

A transistor consists of an electrode that switches the current on and off within a "channel" using an electric field. In the past, to make the transistor switch faster, and thereby up its performance, chip makers shortened the electrode and thinned the insulating wall that separates it from the channel.

This is far from ideal, as thinning the wall causes current to leak from the channel into the electrode, wasting heat and electricity. Furthermore, it means more current leakage than the transistor could handle.

Switching speed

Now, in an effort to continue shrinking and speeding up its transistors, Intel has come up with an insulator that transmits a fast-switching electric field even at a relatively large size. The exact composition of this "high-k" material is a secret, but Intel says that it contains hafnium. It is claimed to increase transistor switching speed by 20% and leak five times less current.

In 2003, Intel also had to tweak its process to start making 90 nanometre transistors. Its secret then was to use "strained silicon" in its transistors (see Secret of strained silicon chips revealed). This increased the speed at which current flowed, although Hutcheson says that advance was "a walk in the park" compared with achieving today's leap to high-k insulators.

The change in insulator has also led to a change in the gate electrode material. When high-k materials are deposited next to an electrode made of polysilicon, defects normally arise at the boundary. But this effect disappears when a metal gate is used instead.

Using the new 45 nanometre transistors, dual-core processors will contain 400 million transistors, while quad-core will contain 800 million.

Intel chips push through nano-barrier

New materials have had to be developed to shrink the transistors. TINY TRANSISTORS on this Intel silicon wafer contain the element hafnium, which will necessitate new manufacturing tricks.

The next milestone in the relentless pursuit of smaller, higher performance microchips has been unveiled.

Chip-maker Intel has announced that it will start manufacturing processors using transistors just 45 nanometres (billionths of a metre) wide (wikipedia).

Shrinking the basic building blocks of microchips will make them faster and more efficient.

reposted from: http://news.bbc.co.uk/1/hi/technology/6299147.stm
my highlights / edits

Computer giant IBM has also signalled its intention to start production of chips using the tiny components.

"Big Blue", which developed the transistor technology with partners Toshiba, Sony and AMD, intends to incorporate them into its chips in 2008.

Intel said it would start commercial fabrication of processors at three factories later this year.

Critical leaks

The development means the fundamental "law" that underpins the development of all microchips, known as Moore's Law, remains intact.

The proposition, articulated by Intel co-founder Gordon Moore in 1965, states that the number of transistors on a chip could double every 24 months.

After more than 10 years of effort, we now have a way forward Tze-chiang Chen, IBM

The new Intel processors, codenamed Penryn, will pack more than four hundred million transistors into a chip half the size of a postage stamp.

Like current processors, they will come in dual-core and quad-core versions, meaning they will have two or four separate processors on each chip. The company has not said how fast the new devices will run.

The production of 45nm technology has been the goal of chip manufacturers ever since they conquered 65nm transistors.

A transistor is a basic electronic switch. Every chip needs a certain number of them, and the more there are and the faster they can switch, the more calculations chips can do.

For more than 45 years, chip manufacturers have managed to keep up with Moore's Law, shrinking transistor size and packing more and more of them on to chips.

However, past the 65nm barrier the silicon used to manufacture critical elements of the switches known as gate dielectrics no longer performs as it does at larger scales.

As a result, currents passing through the transistors leak and reduce the effectiveness of the chip.

To prevent this, researchers have had to develop new materials to contain the current at such small scales. The class of silicon substitutes are known as high-k metals.

Same 'tools'

Their development and integration into working components was described by Gordon Moore as "the biggest change in transistor technology" since the late 1960s.

The first working chips to incorporate 45nm devices were demonstrated last year by Intel, but they have never been incorporated into commercial products.

Dr Tze-chiang Chen, vice president of science and technology at IBM Research, said: "Until now, the chip industry was facing a major roadblock in terms of how far we could push current technology.

"After more than 10 years of effort, we now have a way forward."

The exact recipes for the different high-k metals used by Intel and IBM have not been disclosed, but importantly both firms have said that they could be incorporated into current production technology with minimal effort.

Braces 'may not boost happiness'

Braces may not be beneficial for minor teeth problems

Having braces to correct crooked teeth as a child does not improve mental well-being or quality of life in adulthood, a UK study suggests.

reposted from: http://news.bbc.co.uk/1/hi/health/6295727.stm
my highlights / edits

A 20-year study found that orthodontic treatment had little positive impact on future psychological health.

The researchers said more funding was needed for children with severe teeth problems instead of focusing on those with minor irregularities.

The study is published in the British Journal of Health Psychology.

The researchers said there was a widespread belief in the dental profession that orthodontics improved self-esteem and psychological well-being but evidence was lacking.

Before your child starts treatment there should be a careful discussion about whether there's any benefit. It shouldn't just be an automatic thing Professor Bill Shaw

Around 1,000 Welsh schoolchildren were followed from 1981, when they were 10 or 11 years old to 2001, when they were in their 30s.

Those who had received treatment such as braces had better tooth alignment and were happier with their teeth, but this had not had an impact on their self-esteem or emotional health compared with those who hadn't had any work done, the study concluded.

Lack of treatment in children who would have qualified did not lead to psychological difficulties in later life, the study reported.

Previous research published by the same team found that not having orthodontic work done as a child did not have an adverse effect on future dental health.

Strict criteria

Thousands of children have orthodontic work done each year.

Study leader Professor Bill Shaw, professor of orthodontics at the University of Manchester dental schoo,l said the dental profession had been getting more strict about which children should have treatment.

"The findings confirm early work that has influenced British orthodontics in recent years."

He said hospital orthodontists had been working to a 10-point scale for the past decade to decide whether children needed braces to correct their teeth for dental health or cosmetic reasons.

However, it has only recently become mandatory for dentists and orthodontists working in the community to stick to the same scale for NHS work.

It has been estimated that around 15% fewer children will now have braces on the NHS.

"Before your child starts treatment there should be a careful discussion about whether there's any benefit. It shouldn't just be an automatic thing," he said.

He said more funding was needed because in some areas of the country children with severe teeth problems did not have access to orthodontists.

"It's about making sure it's available and done well and not squandering money the NHS doesn't have on treatments that are marginal."

Iain Hathorn, chair of the British Orthodontic Society, said that the results of the study had contributed to the dental profession's understanding of orthodontics on the well-being of patients.

But he added: "What must be taken into account, however, is that we live in a very different era; attitudes to beauty have changed and orthodontic techniques and materials have improved; so has patients' willingness to wear retainers to maintain the benefits of treatment.

"If the survey was under way today, the picture would perhaps be very different."

"There are patients around the UK clamouring for treatment who would find it very hard to believe that orthodontics did not impart a psychological health gain," Mr Hathorn said.