Eating Less May Not Extend Human Life: Caloric Restriction May Benefit Only Obese Mice
ScienceDaily (Jan. 26, 2009) — If you are a mouse on the chubby side, then eating less may help you live longer.
For lean mice – and possibly for lean humans, the authors of a new study predict – the anti-aging strategy known as caloric restriction may be a pointless, frustrating and even dangerous exercise.
"Today there are a lot of very healthy people who look like skeletons because they bought into this," said Raj Sohal, professor at the University of Southern California's School of Pharmacy.
He and Michael Forster, of the University of North Texas Health Science Center, compared the life span and caloric intake of two genetically engineered strains of mice.
The "fat" strain, known as C57BL/6, roughly doubles in weight over its adult life. That strain benefited from caloric restriction, Sohal said.
The "lean" strain, DBA/2, does not become obese. Caloric restriction did not extend the life of these mice, confirming previous work by Forster and Sohal.
"Our study questions the paradigm that caloric restriction is universally beneficial," Sohal said. "Contrary to what is widely believed, caloric restriction does not extend (the) life span of all strains of mice."
By measuring the animals' metabolic rate, Sohal and his colleagues came to a deceptively simple conclusion: Caloric restriction is only useful when, as in the case of the obese mice, an animal eats more than it can burn off.
"Your energy expenditure and your energy intake should be in balance," Sohal said. "It's as simple as that. And how do you know that? By gain or loss of weight.
"The whole thing is very commonsensical."
For humans of normal weight, Sohal strongly cautions against caloric restriction. In a 2003 study, he and Forster found that caloric restriction begun in older mice – both in DBA and leaner C57 individuals – actually shortened life span.
However, Sohal said that obese individuals are probably better off cutting calories than increasing their exercise to make up for overeating. Overly vigorous exercise can lead to injuries and long-term wear and tear.
In other words, it is better to skip the double cheeseburger than to turn up the treadmill after binging at Carl's Jr.
Sohal's study is not the first to question the allegedly universal benefits of caloric restriction. A study by Ross et al. published in Nature in 1976 ("Dietary practices and growth responses as predictors of longevity") found that caloric restriction works best in mice that gain weight rapidly in early adulthood, Sohal said.
Studies of caloric restriction in wild types of mouse strains have shown minimal life span extension, he added.
Next, the researchers want to understand why the obese mice have a lower metabolic rate that promotes weight gain.
The other members of the research team were Melissa Ferguson and Barbara Sohal of the USC School of Pharmacy.
Funding for the study came from the National Institute on Aging, part of the National Institutes of Health.
Monday, January 26, 2009
Friday, January 23, 2009
Teleportation Milestone Achieved | LiveScience
Scientists have come a bit closer to achieving the "Star Trek" feat of teleportation. No one is galaxy-hopping, or even beaming people around, but for the first time, information has been teleported between two separate atoms across a distance of a meter — about a yard.
This is a significant milestone in a field known as quantum information processing, said Christopher Monroe of the Joint Quantum Institute at the University of Maryland, who led the effort.
Teleportation is one of nature's most mysterious forms of transport: Quantum information, such as the spin of a particle or the polarization of a photon, is transferred from one place to another, without traveling through any physical medium. It has previously been achieved between photons (a unit, or quantum, of electromagnetic radiation, such as light) over very large distances, between photons and ensembles of atoms, and between two nearby atoms through the intermediary action of a third.
None of those, however, provides a feasible means of holding and managing quantum information over long distances.
Now the JQI team, along with colleagues at the University of Michigan, has succeeded in teleporting a quantum state directly from one atom to another over a meter. That capability is necessary for workable quantum information systems because they will require memory storage at both the sending and receiving ends of the transmission.
In the Jan. 23 issue of the journal Science, the scientists report that, by using their protocol, atom-to-atom teleported information can be recovered with perfect accuracy about 90 percent of the time — and that figure can be improved.
"Our system has the potential to form the basis for a large-scale 'quantum repeater' that can network quantum memories over vast distances," Monroe said. "Moreover, our methods can be used in conjunction with quantum bit operations to create a key component needed for quantum computation."
A quantum computer could perform certain tasks, such as encryption-related calculations and searches of giant databases, considerably faster than conventional machines. The effort to devise a working model is a matter of intense interest worldwide.
Teleportation and entanglement
Physicist Richard Feynman is quoted as having said that "if you think you understand quantum mechanics, you don't understand quantum mechanics." Or sometimes he is cited thusly: "I think I can safely say that nobody understand quantum mechanics."
Nonetheless, here is how the University of Maryland describes Monroe's work.
Teleportation works because of a remarkable quantum phenomenon called entanglement which only occurs on the atomic and subatomic scale. Once two objects are put in an entangled state, their properties are inextricably entwined. Although those properties are inherently unknowable until a measurement is made, measuring either one of the objects instantly determines the characteristics of the other, no matter how far apart they are.
The JQI team set out to entangle the quantum states of two individual ytterbium ions so that information embodied in the condition of one could be teleported to the other. Each ion was isolated in a separate high-vacuum trap, suspended in an invisible cage of electromagnetic fields and surrounded by metal electrodes.
The researchers identified two readily discernible ground (lowest energy) states of the ions that would serve as the alternative "bit" values of an atomic quantum bit, or qubit.Conventional electronic bits (short for binary digits), such as those in a personal computer, are always in one of two states: off or on, 0 or 1, high or low voltage, etc. Quantum bits, however, can be in some combination, called a "superposition," of both states at the same time, like a coin that is simultaneously heads and tails — until a measurement is made. It is this phenomenon that gives quantum computation its extraordinary power.
Laser pulse initiates process
At the start of the experimental process, each ion (designated A and B) is initialized in a given ground state.
Then ion A is irradiated with a specially tailored microwave burst from one of its cage electrodes, placing the ion in some desired superposition of the two qubit states — in effect "writing" into "memory" the information to be teleported.
Immediately thereafter, both ions are excited by a picosecond (one trillionth of a second) laser pulse. The pulse duration is so short that each ion emits only a single photon as it sheds the energy gained by the laser and falls back to one or the other of the two qubit ground states.
Depending on which one it falls into, the ion emits one of two kinds of photons of slightly different wavelengths (designated red and blue) that correspond to the two atomic qubit states. It is the relationship between those photons that will eventually provide the telltale signal that entanglement has occurred.
Beamsplitter encounter
Each emitted photon is captured by a lens, routed to a separate strand of fiber-optic cable, and carried to a 50-50 beamsplitter where it is equally probable for the photon to pass straight through the splitter or to be reflected. On either side of the beamsplitter are detectors that can record the arrival of a single photon.
Before it reaches the beamsplitter, each photon is in an unknowable superposition of states. After encountering the beamsplitter, however, each takes on specific characteristics.
As a result, for each pair of photons, four color combinations are possible — blue-blue, red-red, blue-red and red-blue — as well as one of two polarizations: horizontal or vertical. In nearly all of those variations, the photons either cancel each other out or both end up in the same detector. But there is one — and only one — combination in which both detectors will record a photon at exactly the same time.
In that case, however, it is physically impossible to tell which ion produced which photon because it cannot be known whether the photon arriving at a detector passed through the beamsplitter or was reflected by it.
Thanks to the peculiar laws of quantum mechanics, that inherent uncertainty projects the ions into an entangled state. That is, each ion is in a superposition of the two possible qubit states. The simultaneous detection of photons at the detectors does not occur often, so the laser stimulus and photon emission process has to be repeated many thousands of times per second. But when a photon appears in each detector, it is an unambiguous signature of entanglement between the ions.
When an entangled condition is identified, the scientists immediately take a measurement of ion A. The act of measurement forces it out of superposition and into a definite condition: one of the two qubit states.
But because ion A's state is irreversibly tied to ion B's, the measurement also forces B into the complementary state. Depending on which state ion A is found in, the researchers now know precisely what kind of microwave pulse to apply to ion B in order to recover the exact information that had been written to ion A by the original microwave burst. Doing so results in the accurate teleportation of the information.
Teleportation vs. other communications
What distinguishes this outcome as teleportation, rather than any other form of communication, is that no information pertaining to the original memory actually passes between ion A and ion B. Instead, the information disappears when ion A is measured and reappears when the microwave pulse is applied to ion B.
"One particularly attractive aspect of our method is that it combines the unique advantages of both photons and atoms," says Monroe. "Photons are ideal for transferring information fast over long distances, whereas atoms offer a valuable medium for long-lived quantum memory ... Also, the teleportation of quantum information in this way could form the basis of a new type of quantum internet that could outperform any conventional type of classical network for certain tasks."
The work was supported by the Intelligence Advanced Research Project Activity program under U.S. Army Research Office contract, the National Science Foundation (NSF) Physics at the Information Frontier Program, and the NSF Physics Frontier Center at the Joint Quantum Institute.
This is a significant milestone in a field known as quantum information processing, said Christopher Monroe of the Joint Quantum Institute at the University of Maryland, who led the effort.
Teleportation is one of nature's most mysterious forms of transport: Quantum information, such as the spin of a particle or the polarization of a photon, is transferred from one place to another, without traveling through any physical medium. It has previously been achieved between photons (a unit, or quantum, of electromagnetic radiation, such as light) over very large distances, between photons and ensembles of atoms, and between two nearby atoms through the intermediary action of a third.
None of those, however, provides a feasible means of holding and managing quantum information over long distances.
Now the JQI team, along with colleagues at the University of Michigan, has succeeded in teleporting a quantum state directly from one atom to another over a meter. That capability is necessary for workable quantum information systems because they will require memory storage at both the sending and receiving ends of the transmission.
In the Jan. 23 issue of the journal Science, the scientists report that, by using their protocol, atom-to-atom teleported information can be recovered with perfect accuracy about 90 percent of the time — and that figure can be improved.
"Our system has the potential to form the basis for a large-scale 'quantum repeater' that can network quantum memories over vast distances," Monroe said. "Moreover, our methods can be used in conjunction with quantum bit operations to create a key component needed for quantum computation."
A quantum computer could perform certain tasks, such as encryption-related calculations and searches of giant databases, considerably faster than conventional machines. The effort to devise a working model is a matter of intense interest worldwide.
Teleportation and entanglement
Physicist Richard Feynman is quoted as having said that "if you think you understand quantum mechanics, you don't understand quantum mechanics." Or sometimes he is cited thusly: "I think I can safely say that nobody understand quantum mechanics."
Nonetheless, here is how the University of Maryland describes Monroe's work.
Teleportation works because of a remarkable quantum phenomenon called entanglement which only occurs on the atomic and subatomic scale. Once two objects are put in an entangled state, their properties are inextricably entwined. Although those properties are inherently unknowable until a measurement is made, measuring either one of the objects instantly determines the characteristics of the other, no matter how far apart they are.
The JQI team set out to entangle the quantum states of two individual ytterbium ions so that information embodied in the condition of one could be teleported to the other. Each ion was isolated in a separate high-vacuum trap, suspended in an invisible cage of electromagnetic fields and surrounded by metal electrodes.
The researchers identified two readily discernible ground (lowest energy) states of the ions that would serve as the alternative "bit" values of an atomic quantum bit, or qubit.Conventional electronic bits (short for binary digits), such as those in a personal computer, are always in one of two states: off or on, 0 or 1, high or low voltage, etc. Quantum bits, however, can be in some combination, called a "superposition," of both states at the same time, like a coin that is simultaneously heads and tails — until a measurement is made. It is this phenomenon that gives quantum computation its extraordinary power.
Laser pulse initiates process
At the start of the experimental process, each ion (designated A and B) is initialized in a given ground state.
Then ion A is irradiated with a specially tailored microwave burst from one of its cage electrodes, placing the ion in some desired superposition of the two qubit states — in effect "writing" into "memory" the information to be teleported.
Immediately thereafter, both ions are excited by a picosecond (one trillionth of a second) laser pulse. The pulse duration is so short that each ion emits only a single photon as it sheds the energy gained by the laser and falls back to one or the other of the two qubit ground states.
Depending on which one it falls into, the ion emits one of two kinds of photons of slightly different wavelengths (designated red and blue) that correspond to the two atomic qubit states. It is the relationship between those photons that will eventually provide the telltale signal that entanglement has occurred.
Beamsplitter encounter
Each emitted photon is captured by a lens, routed to a separate strand of fiber-optic cable, and carried to a 50-50 beamsplitter where it is equally probable for the photon to pass straight through the splitter or to be reflected. On either side of the beamsplitter are detectors that can record the arrival of a single photon.
Before it reaches the beamsplitter, each photon is in an unknowable superposition of states. After encountering the beamsplitter, however, each takes on specific characteristics.
As a result, for each pair of photons, four color combinations are possible — blue-blue, red-red, blue-red and red-blue — as well as one of two polarizations: horizontal or vertical. In nearly all of those variations, the photons either cancel each other out or both end up in the same detector. But there is one — and only one — combination in which both detectors will record a photon at exactly the same time.
In that case, however, it is physically impossible to tell which ion produced which photon because it cannot be known whether the photon arriving at a detector passed through the beamsplitter or was reflected by it.
Thanks to the peculiar laws of quantum mechanics, that inherent uncertainty projects the ions into an entangled state. That is, each ion is in a superposition of the two possible qubit states. The simultaneous detection of photons at the detectors does not occur often, so the laser stimulus and photon emission process has to be repeated many thousands of times per second. But when a photon appears in each detector, it is an unambiguous signature of entanglement between the ions.
When an entangled condition is identified, the scientists immediately take a measurement of ion A. The act of measurement forces it out of superposition and into a definite condition: one of the two qubit states.
But because ion A's state is irreversibly tied to ion B's, the measurement also forces B into the complementary state. Depending on which state ion A is found in, the researchers now know precisely what kind of microwave pulse to apply to ion B in order to recover the exact information that had been written to ion A by the original microwave burst. Doing so results in the accurate teleportation of the information.
Teleportation vs. other communications
What distinguishes this outcome as teleportation, rather than any other form of communication, is that no information pertaining to the original memory actually passes between ion A and ion B. Instead, the information disappears when ion A is measured and reappears when the microwave pulse is applied to ion B.
"One particularly attractive aspect of our method is that it combines the unique advantages of both photons and atoms," says Monroe. "Photons are ideal for transferring information fast over long distances, whereas atoms offer a valuable medium for long-lived quantum memory ... Also, the teleportation of quantum information in this way could form the basis of a new type of quantum internet that could outperform any conventional type of classical network for certain tasks."
The work was supported by the Intelligence Advanced Research Project Activity program under U.S. Army Research Office contract, the National Science Foundation (NSF) Physics at the Information Frontier Program, and the NSF Physics Frontier Center at the Joint Quantum Institute.
Sunday, January 11, 2009
14 Percent of U.S. Adults Can't Read | LiveScience
14 Percent of U.S. Adults Can't Read LiveScience
About 14 percent of U.S. adults won't be reading this article. Well, okay, most people won't read it, given all the words that are published these days to help us understand and navigate the increasingly complex world.
But about 1 in 7 can't read it. They're illiterate.
Statistics released by the U.S. Education Department this week show that some 32 million U.S. adults lack basic prose literacy skill. That means they can't read a newspaper or the instruction on a bottle of pills.
The figures are for 2003, the latest year available. State and county results are available here.
"The crisis of adult literacy is getting worse, and investment in education and support programs is critical," said David C. Harvey, president and CEO of ProLiteracy, in response to the finding.
This is about jobs and the economy, Harvey said.
"More than 1 million people lost their jobs in 2008 and the new unemployment figures are the highest in 16 years," Harvey said. "A large number of the unemployed are low-skilled individuals who struggle with everyday reading, writing and math tasks. The administration wants to create new jobs with the stimulus packages, but to take advantage of those new positions, these adults need basic literacy skills."
A separate study released last month named Minneapolis and Seattle as the most literate cities.
ProLiteracy, which promotes reading programs for the disadvantaged and encourages more government funding, estimates that illiteracy costs American businesses more than $60 billion each year in lost productivity and health and safety issues. Lack of funding at the federal, state and local levels prevents about 90 percent of the illiterate from getting help, the organization claims.
ProLiteracy also estimates:
63 percent of prison inmates can't read
774 million people worldwide are illiterate
Two-thirds of the world's illiterate are women
If parents can't read, there's a good chance children will be poor readers, the organization notes.
About 14 percent of U.S. adults won't be reading this article. Well, okay, most people won't read it, given all the words that are published these days to help us understand and navigate the increasingly complex world.
But about 1 in 7 can't read it. They're illiterate.
Statistics released by the U.S. Education Department this week show that some 32 million U.S. adults lack basic prose literacy skill. That means they can't read a newspaper or the instruction on a bottle of pills.
The figures are for 2003, the latest year available. State and county results are available here.
"The crisis of adult literacy is getting worse, and investment in education and support programs is critical," said David C. Harvey, president and CEO of ProLiteracy, in response to the finding.
This is about jobs and the economy, Harvey said.
"More than 1 million people lost their jobs in 2008 and the new unemployment figures are the highest in 16 years," Harvey said. "A large number of the unemployed are low-skilled individuals who struggle with everyday reading, writing and math tasks. The administration wants to create new jobs with the stimulus packages, but to take advantage of those new positions, these adults need basic literacy skills."
A separate study released last month named Minneapolis and Seattle as the most literate cities.
ProLiteracy, which promotes reading programs for the disadvantaged and encourages more government funding, estimates that illiteracy costs American businesses more than $60 billion each year in lost productivity and health and safety issues. Lack of funding at the federal, state and local levels prevents about 90 percent of the illiterate from getting help, the organization claims.
ProLiteracy also estimates:
63 percent of prison inmates can't read
774 million people worldwide are illiterate
Two-thirds of the world's illiterate are women
If parents can't read, there's a good chance children will be poor readers, the organization notes.
Life As We Know It Nearly Created in Lab | LiveScience
Life As We Know It Nearly Created in Lab LiveScience
One of life's greatest mysteries is how it began. Scientists have pinned it down to roughly this:
Some chemical reactions occurred about 4 billion years ago — perhaps in a primordial tidal soup or maybe with help of volcanoes or possibly at the bottom of the sea or between the mica sheets — to create biology.
Now scientists have created something in the lab that is tantalizingly close to what might have happened. It's not life, they stress, but it certainly gives the science community a whole new data set to chew on.
The researchers, at the Scripps Research Institute, created molecules that self-replicate and even evolve and compete to win or lose. If that sounds exactly like life, read on to learn the controversial and thin distinction.
Know your RNA
To understand the remarkable breakthrough, detailed Jan. 8 in the early online edition of the journal Science, you have to know a little about molecules called RNA and DNA.
DNA is the software of life, the molecules that pack all the genetic information of a cell. DNA and the genes within it are where mutations occur, enabling changes that create new species.
RNA is the close cousin to DNA. More accurately, RNA is thought to be a primitive ancestor of DNA. RNA can't run a life form on its own, but 4 billion years ago it might have been on the verge of creating life, just needing some chemical fix to make the leap. In today's world, RNA is dependent on DNA for performing its roles, which include coding for proteins.
If RNA is in fact the ancestor to DNA, then scientists have figured they could get RNA to replicate itself in a lab without the help of any proteins or other cellular machinery. Easy to say, hard to do.
But that's exactly what the Scripps researchers did. Then things went surprisingly further.
'Immortalized'
Specifically, the researchers synthesized RNA enzymes that can replicate themselves without the help of any proteins or other cellular components, and the process proceeds indefinitely. "Immortalized" RNA, they call it, at least within the limited conditions of a laboratory.
More significantly, the scientists then mixed different RNA enzymes that had replicated, along with some of the raw material they were working with, and let them compete in what's sure to be the next big hit: "Survivor: Test Tube."
Remarkably, they bred.
And now and then, one of these survivors would screw up, binding with some other bit of raw material it hadn't been using. Hmm. That's exactly what life forms do ...
When these mutations occurred, "the resulting recombinant enzymes also were capable of sustained replication, with the most fit replicators growing in number to dominate the mixture," the scientists report.
The "creatures" — wait, we can't call them that! — evolved, with some "species" winning out.
"It kind of blew me away," said team member Tracey Lincoln of the Scripps Research Institute, who is working on her Ph.D. "What we have is non-living, but we've been able to show that it has some life-like properties, and that was extremely interesting."
Indeed.
Knocking on life's door
Lincoln's advisor, professor Gerald Joyce, reiterated that while the self-replicating RNA enzyme systems share certain characteristics of life, they are not life as we know it.
"What we've found could be relevant to how life begins, at that key moment when Darwinian evolution starts," Joyce said in a statement.
Joyce's restraint, clear also on an NPR report of the finding, has to be appreciated. He allows that some scientists familiar with the work have argued that this is life. Another scientist said that what the researchers did is equivalent to recreating a scenario that might have led to the origin of life.
Joyce insists he and Lincoln have not created life: "We're knocking on that door," he says, "but of course we haven't achieved that."
Only when a system is developed in the lab that has the capability of evolving novel functions on its own can it be properly called life, Joyce said. In short, the molecules in Joyce's lab can't evolve any totally new tricks, he said.
One of life's greatest mysteries is how it began. Scientists have pinned it down to roughly this:
Some chemical reactions occurred about 4 billion years ago — perhaps in a primordial tidal soup or maybe with help of volcanoes or possibly at the bottom of the sea or between the mica sheets — to create biology.
Now scientists have created something in the lab that is tantalizingly close to what might have happened. It's not life, they stress, but it certainly gives the science community a whole new data set to chew on.
The researchers, at the Scripps Research Institute, created molecules that self-replicate and even evolve and compete to win or lose. If that sounds exactly like life, read on to learn the controversial and thin distinction.
Know your RNA
To understand the remarkable breakthrough, detailed Jan. 8 in the early online edition of the journal Science, you have to know a little about molecules called RNA and DNA.
DNA is the software of life, the molecules that pack all the genetic information of a cell. DNA and the genes within it are where mutations occur, enabling changes that create new species.
RNA is the close cousin to DNA. More accurately, RNA is thought to be a primitive ancestor of DNA. RNA can't run a life form on its own, but 4 billion years ago it might have been on the verge of creating life, just needing some chemical fix to make the leap. In today's world, RNA is dependent on DNA for performing its roles, which include coding for proteins.
If RNA is in fact the ancestor to DNA, then scientists have figured they could get RNA to replicate itself in a lab without the help of any proteins or other cellular machinery. Easy to say, hard to do.
But that's exactly what the Scripps researchers did. Then things went surprisingly further.
'Immortalized'
Specifically, the researchers synthesized RNA enzymes that can replicate themselves without the help of any proteins or other cellular components, and the process proceeds indefinitely. "Immortalized" RNA, they call it, at least within the limited conditions of a laboratory.
More significantly, the scientists then mixed different RNA enzymes that had replicated, along with some of the raw material they were working with, and let them compete in what's sure to be the next big hit: "Survivor: Test Tube."
Remarkably, they bred.
And now and then, one of these survivors would screw up, binding with some other bit of raw material it hadn't been using. Hmm. That's exactly what life forms do ...
When these mutations occurred, "the resulting recombinant enzymes also were capable of sustained replication, with the most fit replicators growing in number to dominate the mixture," the scientists report.
The "creatures" — wait, we can't call them that! — evolved, with some "species" winning out.
"It kind of blew me away," said team member Tracey Lincoln of the Scripps Research Institute, who is working on her Ph.D. "What we have is non-living, but we've been able to show that it has some life-like properties, and that was extremely interesting."
Indeed.
Knocking on life's door
Lincoln's advisor, professor Gerald Joyce, reiterated that while the self-replicating RNA enzyme systems share certain characteristics of life, they are not life as we know it.
"What we've found could be relevant to how life begins, at that key moment when Darwinian evolution starts," Joyce said in a statement.
Joyce's restraint, clear also on an NPR report of the finding, has to be appreciated. He allows that some scientists familiar with the work have argued that this is life. Another scientist said that what the researchers did is equivalent to recreating a scenario that might have led to the origin of life.
Joyce insists he and Lincoln have not created life: "We're knocking on that door," he says, "but of course we haven't achieved that."
Only when a system is developed in the lab that has the capability of evolving novel functions on its own can it be properly called life, Joyce said. In short, the molecules in Joyce's lab can't evolve any totally new tricks, he said.
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