Modulating the lifespan of Caenorhabditis elegans

For The First Time: Longevity Modulated Without Disrupting Life-sustaining Function

Within a hormone-triggered cascade of molecular signals that plays a crucial for a wide range of physiological functions, researchers for the very first time have identified a protein that functions specifically to extend lifespan and youthfulness -- without disrupting fertility, immunity or the organism's response to stress.

In mammals there is a pathway associated with insulin and IGF-1 (insulin-like growth factor-1) which (among other things) affects individual growth and development. But messing around with this pathway can have very undesirable side effects, such as diabetes. In C. elegans there is a cell surface receptor (DAF-2) analogous to the insulin/IGF-1 receptor in mammals. It is known that altering the signaling pathway associated with DAF-2 can extend the worm's lifespan, but there are also undesirable side effects. Now the protein associated with the Smk-1 gene has been found to modulate changes to the DAF-2 pathway so as to avoid the side effects. This suggests that the mammalian insulin/IGF-1 pathway can also be better controlled to enhance lifespan without harming other critical processes.

Related article: Our cousin, Caenorhabditis elegans

Tags: biology, aging, longevity, lifespan

Quadratic forms

Significant results in mathematics that are also not highly technical come out too seldomly. So it was nice to see the report by Ivars Peterson in the March 11, 2006 issue of Science News concerning striking recent discoveries by the young mathematician Manjul Bhargava that have to do with long-standing questions in the arithmetic theory of quadratic forms.

The article can be found here or here.

As good as the article is, some readers may be curious about a few relatively simple details which weren't explained.

To begin with, let's have a general definition of quadratic form, that is, a polynomial in 1 or more variables in which every term has degree exactly two. The situation is pretty trivial with only one variable, so normally only cases with two or more variables are considered.

With two variables, x and y, the most general quadratic form would be f(x,y) = ax² + bxy + cy², where the coefficients a, b, and c are numbers rather than variables. To say that all terms have degree two means that the sum of exponents of the variables in one term is two. Another way to express this condition is to say that the polynomial is homogeneous of degree two.

There could be any positive integer number n of variables, in which case the form is said to be n-ary. For small n, the terminology binary, ternary, or quaternary (n = 2, 3, or 4) is used.

An n-ary quadratic form can be written symbolically, using the summation operator Σ, as

f(x₁, ... , x_n) = Σ_{1≤i≤j≤n} q_ijx_ix_j

The numbers q_ij are the coefficients of the form. The condition i≤j on the indices in the summation is so that terms like x_ix_j and x_jx_i are included only once if i ≠ j. This sensible convention actually has interesting consequences, as we'll see in a moment.

The coefficients, in general, could be any sort of numbers. But for purposes of number theory (which is what concerns us here), the coefficients are assumed to be positive integers.

A natural question one may ask in this case is whether a given positive integer n can be represented by a quadratic form, that is, whether the quadratic form takes on the value n for some integer values of the variables. For example, in the simple case of two variables, this amounts to solving the Diophantine equation n = ax² + bxy + cy², where a, b, and c are integers.

It turns out that in order to study the algebra of quadratic forms it is helpful to represent them not as polynomials but as matrices A = (q_ij) that contain the coefficients of the form. (I won't explain matrices here, so if you haven't encountered the idea, it's best to skip ahead.) Then if x = (x₁, ... , x_n) is a row vector whose entries consist of the variable symbols, and x^T is its transpose (a column vector), another way to write the quadratic form is as the matrix product x^TAx = f(x₁, ... , x_n). Unfortunately, there's a kink in this scheme. The matrix will contain coefficients q_ij for all values of i and j between 1 and n. The matrix needs to be symmetric, so that q_ij = q_ji. But then products like x_ix_j get counted twice if i ≠ j, so for the off-diagonal entries of the matrix A it's necessary to use q_ij/2 when i ≠ j. And that's all well and good, unless we're interested in forms with integer coefficients and we need the matrix entries to be integers as well.

To illustrate the problem, consider the form x²+2xy+y². The matrix that corresponds to this is the 2×2 square matrix whose entries are all 1. However, for the form x²+xy+y² the corresponding matrix has 1/2 as the off-diagonal entries. For some purposes that's OK, but for number theory we don't want non-integral matrix elements. So one says that the first form in this example, which has a corresponding matrix with integral entries, is matrix-defined, while the second form is not. (Mathematicians are very picky.)

With these preliminaries out of the way, let's look at what Bhargava (and others) have proved. In 1770 Joseph-Louis Lagrange, one of the earliest number theorists, proved that every positive integer is the sum of at most four non-zero squares. Another way to say this is that the quaternary quadratic form f(x,y,z,w) = x² + y² + z² + w² takes on every possible positive integer value for some value of the variables x, y, z, w. Or, using a term mentioned before, the form represents every positive integer. A quadratic form with this property is said to be universal.

Mathematicians are always looking for generalizations, so the next question one might ask is whether every quaternary quadratic form is universal. That's obviously not the case, since a form like 2x² + 2y² + 2z² + 2w² can represent only even numbers. So the next, but much harder, question is whether there are relatively simple conditions that can identify forms that are universal. Indeed, are there any other forms that are universal, besides Lagrange's? In 1916, the extraordinary Indian mathematician Srinivasa Ramanujan found 53 more universal quaternary quadratic forms with integer coefficients.

Much later, in 1993, John H. Conway and William Schneeberger proved that there's a prety simple condition that guarantees a quadratic form is universal, provided it's also matrix-defined, as explained above. The condition is that in order to be universal and represent every positive integer, it's sufficient for the form to represent just the nine integers 1, 2, 3, 5, 6, 7, 10, 14, and 15. This theorem became known as the "15 theorem". (Conway is an extremely versatile and interesting mathematician himself. Among his other accomplishments are invention of the "Game of Life", the discovery of three "sporadic" finite simple groups, and the discovery (with Simon Kochen) of a "free-will" theorem related to the EPR paradox of quantum mechanics.)

Lagrange's form as well as all 53 discovered by Ramanujan are of the matrix-defined type. So Conway's 15 theorem quickly allows for a proof that all are universal. The next thing one might ask is whether there are only a finite number of universal matrix-defined forms, and if so, exactly how many there are. This is where Bhargava comes in. In the late 1990s, working with Conway as a graduate student at Princeton, Bhargava found a new, simpler proof of the 15 theorem (whose original proof was long and complicated). Using his new ideas, he then proved that there ara exactly 204 different universal matrix-defined quadratic forms. He also proved related results, such as that a matrix-defined form represents all odd numbers if it can represent just 1, 3, 5, 7, 11, 15, and 33. Similarly, a matrix-defined form can represent all prime numbers if it represents just the primes up to 73.

The next step is to try to relax the condition which requires the form to be matrix-defined in order for simple criteria to be applicable. One would like a criterion that can be used for any quadratic form which takes only integer values, even it's not matrix-defined. Just recently Bhargava, working with Jonathan P. Hanke of Duke University, has come up with an answer.

What they found is that there is a set of 29 integers less than or equal to 290 such that a quaternary integer-valued quadratic form is universal if it represents each of those 29 integers. (Conway and Schneeberger had earlier conjectured that testing all numbers from 1 to 290 would be sufficient.) Then, using a computer to check all the cases that could occur, Bhargava and Hanke found that there are exactly 6436 universal, integer-valued, quaternary quadratic forms.

Tags: mathematics, number theory, quadratic form

Breaking news: WMAP data and big bang inflation

Cosmologists and astrophysicists have been biting their nails on this for several years.

The Wilkinson Microwave Anisotropy Probe (WMAP), launched in June 2001, was designed to answer fundamental questions about the oigins of the universe (at least our part of it) from the first instants of the big bang event through the point in time about 400,000 years later when light and matter went their separate ways so that the universe became transparent.

After only a year and a half, in early 2003, data from WMAP about fluctuations in temperature of the cosmic microwave background radiation (CMB) confirmed that only about one sixth of matter in the universe is "ordinary" matter made up mostly of protons and neutrons. And so the remaining five sixths must be "exotic dark matter", whose exact nature is still unknown. (See here.)

In addition, among other things, it was confirmed that the microwave radiation was polarized. These early WMAP observations in themselves were significant enough that the story was chosen as Breakthrough of the Year for 2003 by Science magazine.

The fact that the microwave radiation is polarized is important, because it makes it possible to deduce information about the earliest moments of the big bang. In particular, collection and analysis of further data about the polarization held the potential to confirm or disconfirm a 25-year-old hypothesis known as cosmic inflation, which holds that within only (approximately) 10^-32 of a second after the big bang the universe expanded in size by a factor as much as 10¹⁰⁰.

It has taken WMAP scientists another three years to collect and fully analyze polarization data. In the interim, other cosmologists have anxiously awaited the results. The anxiety level has been high, because WMAP data has the potential to invalidate the inflation hypothesis. In that event, several key facts about the universe which the hyprothesis purports to explain would need to have some entirely different explanation. The big bang theory itself could be called into question.

So the news today that polarization data collected from WMAP in the past three years does not contradict the inflationary scenario is quite a relief. See here for more background.

The inflationary hypothesis was originated around 1980 by Alan Guth, now a professor at MIT. Alan must be feeling pretty good today. If inflation is eventually confirmed, possibly by data from planned experiments such as ESA's Planck Mission, he'll get a Nobel Prize. The latest WMAP results could well be voted breakthrough of the year for 2006, also.

Here's another report on the news: Astronomers Detect First Split-Second of the Universe.

And more detail from Sean Carroll at Cosmic Variance.

Tags: cosmic inflation, big bang, cosmic microwave background, cosmology, WMAP

Google Mars

If you are at all interested in space exploration, Mars in particular, you really need to look at this.

Fats and food fads

Fads and superstitions related to food have been a part of human cultures for a long time. The Old Testament of the Hebrew and Christian Bible, of course, is notorious for nonsense about what is good or bad to eat. For example, Ch. 11 of Leviticus is full of it:

[1] And the LORD spake unto Moses and to Aaron, saying unto them,
[2] Speak unto the children of Israel, saying, These are the beasts which ye shall eat among all the beasts that are on the earth.
[3] Whatsoever parteth the hoof, and is clovenfooted, and cheweth the cud, among the beasts, that shall ye eat.
[4] Nevertheless these shall ye not eat of them that chew the cud, or of them that divide the hoof: as the camel, because he cheweth the cud, but divideth not the hoof; he is unclean unto you.
[5] And the coney, because he cheweth the cud, but divideth not the hoof; he is unclean unto you.
[6] And the hare, because he cheweth the cud, but divideth not the hoof; he is unclean unto you.
[7] And the swine, though he divide the hoof, and be clovenfooted, yet he cheweth not the cud; he is unclean to you.
[8] Of their flesh shall ye not eat, and their carcase shall ye not touch; they are unclean to you.
[9] These shall ye eat of all that are in the waters: whatsoever hath fins and scales in the waters, in the seas, and in the rivers, them shall ye eat.
[10] And all that have not fins and scales in the seas, and in the rivers, of all that move in the waters, and of any living thing which is in the waters, they shall be an abomination unto you:
[11] They shall be even an abomination unto you; ye shall not eat of their flesh, but ye shall have their carcases in abomination.
[12] Whatsoever hath no fins nor scales in the waters, that shall be an abomination unto you.

There follows the same sort of stuff regarding poultry. Yadda, yadda, yadda in this vein to the end of the chapter. Exactly what is so great about animals that have cloven hooves and chew their cud, or bad about animals that don't, is never quite made clear. But then, these are commandments and you're not supposed to understand. Just do it. And truth be told, commandments like these don't hold a candle to some of the atrocities called for elsewhere in Leviticus. Cultures just seem to accumulate this kind of nonsense as they go along.

But that's getting off topic. There are theories about why certain animals were in or out of favor for eating back in the Bronze Age middle east. Probably it had somewhat to do with avoiding animals that tended to harbor unpleasant parasite-caused diseases, of which folks had no understanding at the time. Steven Pinker also suggests that having a taboo on food that your enemies enjoyed was useful for keeping people from sitting down to a friendly meal with those enemies, finding out they weren't such bad sorts after all, and thereby messing up the butchery and general mayhem planned by the military-industrial complex of that place and time.

Fast forward 30 centuries or so. People in the middle east are still passionately engaged in making hamburger of each other. But in parts of the more civilized world, people now expend more passion debating whether or not it's a good idea to eat hamburger at all. And if so, whether a Big Mac^® is better than a Whopper^®, or whether ground beef with 10% fat is OK, while 20% fat is not.

Fat itself is the subject of much passionate food faddism these days. Until relatively recently in history, it wasn't so much of an issue. Most animals, including humans, faced enough difficulties simply surviving that they had little time to accumulate surpluses of fat. (Except for aquatic mammals like whales and seals which didn't need to worry overly much about the strain on the joints of lugging excess pounds about, and others like bears whose lifestyle of yearly hibernation required storing up calories in large amounts for their annual winter nap.)

Once agricultural technology reached a certain level of efficiency, however, humans discovered that nature had provided them with a fondness for fat in the diet, long before the discovery of Big Macs and fries. Evidently, nature did this because there were actually benefits that accrued from consuming a judicious amount of fat in one's diet, as a means of storing up calories which were so abundant on the occasion that the tribe's hunters succeeded in bagging a mammoth or two, to tide everyone over leaner times when all the mammoths in the area seemed to have left for the Poconos.

But eventually, some clever epidemiologists in N. America noticed that people from parts of the world where diseases like cancer and atherosclerosis were rare soon started suffering from such diseases at rates comparable to those of the natives awhile after the immigrants had relocated to places where consumption of a "western diet" (2 lb. steaks and baked potatoes with sour cream) was the norm. Putting two and two together, it was decided that the cause of this phenomenon was probably too much fat in the diet.

Thus was born the doctrine that fat in the diet is a Bad Thing. The medical community was not long in accepting this idea. It became the conventional wisdom in recent decades. There was even a lot of evidence for some of the apparent ill effects of excess fat in the diet, particularly various forms of cardiovascular disease.

The evidence for an association between high-fat diets and cancer was thought to be there too. The AMA endorsed the idea. For example, their Family Health Cookbook stated bluntly

Maintaining your optimal body weight is important because being overweight elevates the risk for certain types of cancer, such as colon cancer (cancer of part of the large intestine), in men and women. Carrying a lot of weight in the abdomen has been linked to an increased risk of breast cancer in women.

Some physicians took these concerns very seriously indeed, and some among them championed the cause of the Low Fat Diet. One among that number is Dr. John McDougall, who has written extensively on healthy diet -- low-fat diets, in particular. His McDougall Report, for example, states

• The high fat Western diet is the leading cause of cancer, contributing most directly to cancer of the colon, breast, and prostate, but also to other cancers (Lancet 340:162, 1992).
• Cancers common in the Western world are rare in countries where a starch-based diet is still followed. However, as people in these countries change their eating habits, they develop our cancers. For example, breast cancer in Japan is expected to move from the fifth most common cancer among women to number one in the next ten years (Cancer 67:2021, 1991).

The leading cause? Really? That's a pretty strong statement. Does science actually support that... or are we seeing a bit of creeping food faddism? Indeed, in recent years champions have, in fact, emerged for the virtues of low-carbohydrate, high-protein diets, which are almost the opposite of what McDougall recommends. Of course, the high-protein diet is lauded for weight loss more than prevention of diseases like cancer, but still... what's a person to believe about what's good or bad as a healthy diet?

Moreover, cancer is now known to be mainly a disease (a whole family of diseases, actually) that results from DNA defects which eventually lead to uncontrolled cell proliferation. (See here.) So why would excess fat in the diet be the leading cause of cancer? Exactly how good is the scientific evidence for such a conclusion?

Not very good, as it turns out. Not very good at all:

Reducing Total Fat Intake May Lower Breast-Cancer Risk But Has Little Impact on Risk of Colon Cancer or Heart Disease

Feb. 7, 2006 — Adopting a low-fat diet in later life and following such a regimen for nearly a decade does not appear to have a significant impact on reducing the overall risk of breast cancer, colorectal cancer or heart disease, according to a Women's Health Initiative study that involved nearly 50,000 postmenopausal women across the United States.

Here are some additional articles on this research:

• Low-fat diet may not reduce cancer and heart risks
  
• Low-fat Diet's Benefits For Women Less Than Expected
  
• National study finds no effect from reducing total dietary fat
  
• Large study shows low-fat diet has little effect on reducing risk of breast cancer
  
• Low-fat diet does not reduce risk of colorectal cancer
  

This research is not without its problems. Some of the criticisms:

• Only post-menopausal women were studied, not younger women or any men.
  
• The study lasted "only" eight years, possibly not long enough to show much effect.
  
• The target for reduction of fat in the diet was low (to 20% of consumed calories, where 10% might have been better), and many participants didn't achieve the target.
  
• No effort was made to focus on specific components in the diet, such as cholesterol, instead of overall fat consumption.
  

Gina Kolata in the New York Times has a lengthy article (Maybe You're Not What You Eat) on the subject putting it all in the context of food faddism, and especially in relation to common beliefs in American culture.

"It's one of the great principles — no, more than principles, canons — of American culture to suggest that what you eat affects your health," says James Morone, a professor of political science at Brown University.

"It's this idea that you control your own destiny and that it's never too late to reinvent yourself," he said. "Vice gets punished and virtue gets rewarded. If you eat or drink or inhale the wrong things you get sick. If not, you get healthy."

That very American canon, he and others say, may in part explain the criticism and disbelief that last week greeted a report that a low-fat diet might not prevent breast cancer, colon cancer or heart disease, after all.

The report, from a huge federal study called the Women's Health Initiative, raises important questions about how much even the most highly motivated people can change their eating habits and whether the relatively small changes that they can make really have a substantial effect on health.

So what's next? Where do we go from here? Is what we need a study with twice as many participants, including men as well as women? Should it start with much younger people and run for 20 or 30 years? That's bound to be quite expensive -- and a lapse of time extending an entire generation.

It occurs to me that a better idea, or at least something additional to try, is to zero in on the exact mechanisms through which dietary fats of particular types affect the development of specific cancers. The goal should be to determine exactly what it is that's harmful about specific types of fat in the diet, in the same way we study other carcinogens and other factors that cause DNA damage.

Here are a couple of recent studies that take this approach:

• Omega-6 fats cause prostate tumors to grow twice as fast
  
• Fat Overload Kills Mammalian Cells -- Key Culprit Identified
  

Not only would such research probably produce results more quickly, but it offers the hope of results that are more useful in preventing cancer. Rather than assuming only a major lifestyle change will suffice -- a change which could be just too difficult to be adopted widely enough -- perhaps we can discover medicines or other more targeted means to overcome the specific effects of dietary fat that are most likely to lead to cancer.

Tags: low-fat diet, dietary fat, cancer, health, medicine

Steven Pinker writes on the work of Richard Dawkins

Two guys whose work I admire a lot. How could I not comment on this?

Yes, genes can be selfish

Oxford University Press is publishing a 30^th aniversity edition of Dawkins' The Selfish Gene. Nearly simultaneously they're publishing a book of essays on Dawkins' oeuvre by Alan Grafen and Mark Ridley: Richard Dawkins: How a Scientist Changed the Way We Think.

An extract from Pinker's essay in that volume is what is linked to here at the top. Commenting on it in the detail it deserves would amount to writing another essay like those in the Grafen and Ridley book. So I'll just note a few things.

Pinker is a cognitive scientist while Dawkins is an evolutionary biologist. But Pinker was struck by similarities in the ways the two of them approach their respective specialties.

When I first read Dawkins I was immediately gripped by concerns in his writings on life that were richer versions of ones that guided my thinking on the mind. The parallels concerned both the content and the practice of the relevant sciences.

A major theme in Dawkins’s writings on life that has important parallels in the understanding of the mind is a focus on information. In The Blind Watchmaker Dawkins wrote: “If you want to understand life, don’t think about vibrant, throbbing gels and oozes, think about information technology.” Dawkins has tirelessly emphasised the centrality of information in biology — the storage of genetic information in DNA, the computations embodied in transcription and translation, and the cybernetic feedback loop that constitutes the central mechanism of natural selection itself, in which seemingly goal-oriented behavior results from the directed adjustment of some process by its recent consequences.

The rest of the essay (at least the part in the extract here) goes on to elaborate on this theme. Regarding the similarities between Dawkins' thinking and cognitive science, we have:

[W]hen it comes down to the deepest understanding of what life is, how it works, and what forms it is likely to take elsewhere in the universe, Dawkins implies that it is abstract conceptions of information, computation, and feedback, and not nucleic acids, sugars, lipids, and proteins, that will lie at the root of the explanation.

All this has clear parallels in the understanding of the mind. The “cognitive revolution” of the 1950s, which connected psychology with the nascent fields of information theory, computer science, generative linguistics and artificial intelligence, had as its central premise the idea that knowledge is a form of information, thinking a form of computation, and organised behaviour a product of feedback and other control processes. This gave birth to a new science of cognition that continues to dominate psychology today, embracing computer simulations of cognition as a fundamental theoretical tool, and the framing of hypotheses about computational architecture (serial versus parallel processing, analogue versus digital computation, graphical versus list-like representations, etc) as a fundamental source of experimental predictions.

Another notable feature of Dawkins work is his use of mentalistic metaphors (such as "selfish") to shed light on the evolution of genes and organisms. This way of describing evolution is often misunderstood (perhaps willfully at times) by Dawkins' critics.

Mentalism itself has a checkered career in the history of understanding organisms, especially humans, but in recent decades it has been rehabilitated, when properly understood. Contrary to the ideas of behaviorism, it's now considered proper to discuss the behavior of animals (and humans) in terms (loosely) of what goes on in their minds.

Another shared theme in life and mind made prominent in Dawkins’s writings is the use of mentalistic concepts (ie, the explanation of behaviour in terms of beliefs and desires) in biology.

I mention this in particular because I had ideas like this myself many years ago -- most likely not original, though I'm not aware of specifically what influenced me. For example, there is the idea that it may be possible to "explain" an individual's personality partly in terms of explicit beliefs the individual holds. E. g., a person may be domineering out of a firm conviction that people are either leaders or followers, and that he is especially suited because of status and ability to direct the activities of others. The conventional thinking, I surmise, would be that causality runs in the opposite direction -- that somehow a person's physical makeup or life experiences disposes him to be domineering, and hence to rationalize certain beliefs. This sort of view leads to trying to explain social, political, or ideological beliefs in terms of some presumed underlying personality. But it would be interesting to figure out the extent that reality is the other way around.

Perhaps there is a collection of algorithms that a person's brain habitually uses in order to understand and deal with the surrounding reality. Perhaps these algorithms are bundled with beliefs about how the world is structured and how it works, to constitute a model in a person's mind of the external world. In addition to algorithms, the model incorporates data strucures that make up an ontology of what kinds of things the world contains and how they are related. As a whole, it leads the individual to form expectations of how the world will respond to particular behaviors of the individual, which in turn guides the individual's chosen behavior in a given situation. And in this way, algorithms and models -- which are simply types of information, and more commonly referred to as "beliefs" in traditional psychology -- have a lot of influence over actual behavior. If "personality" is simply the typical kinds of behavior that an individual exhibits, then it's not so far-fetched to say that beliefs shape personality at least as much as the other way around. And in particular, "personality" is not simply an inevitable outcome of the physical makeup of a person's brain, nor of his or her genetic heritage.

Well, those are my half-baked ideas, but Pinker says here something similar:

This characterisation of beliefs and desires in terms of information rather than physical incarnation may overarch not only life and mind but other intelligent systems such as machines and societies.

It's interesting to note that this somewhat goes against the grain of Pinker's well-known contention (elaborated in a whole book) that no person starts out as a completely blank slate, with no genetic predispositions at all. Yet it's not inconsistent with that either, because there most likely are algorithms and models of the world that were selected through the process of evolution, carried along as information in human DNA, and wired into our physical thinking apparatus. For instance, in the way we seem "instinctively" to have a fear of the dark, of creatures like snakes and spiders, and of the unfamiliar and unknown.

Tags: neuroscience, cognitive psychology, Steven Pinker, Richard Dawkins, personality

Biowar for Dummies

So, I was just saying here a few days ago how easy it is now to design your own genes with easily available tools. Turns out that not only can you design genes, but it's much easier than I supposed to put them into a real live organism... for good or evil purposes.

Paul Boutin explains pretty clearly on his blog all that he recently learned about this.

Anthrax. Smallpox. Ebola. For thriller writers and policy crusaders, biological warfare was a standard what-if scenario long before anyone mailed anthrax to government and media offices in 2001. Pentagon war games like Dark Winter, held just before 9/11, and this year's Atlantic Storm suggested that terrorists could unleash germs with the killing power of a nuclear weapon.

Scientists, though, have always been skeptical. Only massive, state-sponsored programs—not terrorist cells or lone kooks—pose a plausible threat, they say. As the head of the Federation of American Scientists working group on bioweapons put it in a 2002 Los Angeles Times op-ed: "A significant bioterror attack today would require the support of a national program to succeed."

Or not. A few months ago, Roger Brent, a geneticist who runs a California biotech firm, sent me an unpublished paper in which he wrote that genetically engineered bioweapons developed by small teams are a bigger threat than suitcase nukes.

Brent is one of a growing number of researchers who believe that a bioterrorist wouldn't need a team of virologists and state funding. He says advances in DNA-hacking technology have reached the point where an evil lab assistant with the right resources could do the job.

Yeah, that's sort of worrisome, isn't it?

Tags: biological warfare

Environmental satellite cutbacks

I was going to post about this, but SusanG at Daily Kos beat me to it. I don't move very fast. But it's all good, because she made the points I would have -- and now I don't need to.

The main point is this:

Oh, goody! A twofer! Bush can now claim that global warming doesn't exist because it hasn't been observed or measured AND with a few years of defunding, he (or his Rove-ordained successor) won't be bothered with pesky, alarmist NOAA reports predicting unimaginable devastation. No more silly questions about why he ignored evidence, because there won't be any evidence to ignore. The U.S. simply won't fund it.

Amazing isn't it? They constantly pull off these totally obvious dirty tricks -- and hardly anyone pays attention.

Who ever thought it would be so easy to get away with setting up a 1984-style dictatorship in the U. S.? With such an abundance of news media and information dissemination capability around?

But it turns out to be so easy. Just overload the information channels (owned by huge corporations that depend on manipulating the public's view of "reality") with disinformation and entertaining irrelevance, while choking off valid information at the source -- and lying vigorously whenever necessary.

It's a snap.

Just for the record, here's the original news item:

Budgets Imperil Environmental Satellites

Budget cuts and poor management may be jeopardizing the future of our eyes in orbit America's fleet of environmental satellites, vital tools for forecasting hurricanes, protecting water supplies and predicting global warming.

"The system of environmental satellites is at risk of collapse," said Richard A. Anthes, president of the University Corporation for Atmospheric Research. "Every year that goes by without the system being addressed is a problem."

Also here

Hubble's Largest Galaxy Portrait Offers a New High-Definition View

Hubble's Largest Galaxy Portrait Offers a New High-Definition View

The giant spiral disk of stars, dust, and gas is 170,000 light-years across or nearly twice the diameter of our galaxy, the Milky Way. M101 is estimated to contain at least one trillion stars. Approximately 100 billion of these stars could be like our Sun in terms of temperature and lifetime.

The galaxy's spiral arms are sprinkled with large regions of star-forming nebulae. These nebulae are areas of intense star formation within giant molecular hydrogen clouds. Brilliant young clusters of hot, blue, newborn stars trace out the spiral arms.

Messier 101 - Click for 800×625 image

More information: here

Next generation computer chip lithography

In the competitive world of semiconductor technology, the name of the game is to squeeze as many transistors as possible into every chip. For random-access memory chips this translates directly into more memory on every chip. For central processor chips this allows faster speeds for several reasons. More transistors per chip makes it possible to add more cache memory to the processor chip for faster memory access. In addition, communication between circuit elements is faster the closer together the elements are.

The main way of describing how densely transistors are packed is in terms of "feature size", which is roughly the size of the smallest geometric feature that can be produced. In the current state of the art, with the latest Intel Pentium processor chips, for example, the smallest feature size is 65 nanometers (nm).

In the process of semiconductor fabrication features are created through the process of photolithography. In essence, this amounts to printing the circuits containing all transistors and their interconnections on a semiconductor material in much the same way as photographic images have long been printed on paper.

The main problem with printing very small features using light is the phenomenon of diffraction, which makes it very difficult to print features that are substantially smaller than the wavelength of light. The shortest wavelength of visible light is about 400 nm (violet), which is totally inadequate for feature sizes such as 65 nm.

The current state of the art uses ultraviolet light with wavelengthts of 248 or 193 nm ("deep ultraviolet"). This is just barely able to handle feature sizes of 65 nm by using various tricks of "nanolithography", such as "liquid immersion". It is expected that by 2009 this process will be capable of creating feature sizes of 45 nm. Intel has already demonstrated an experimental system that can do this.

But that's not going to be good enough beyond 2009. New techniques of producing smaller feature sizes around 10 to 30 nm (just a few hundred atoms in width) are now the subjects of active research. Intel is investigating techniques of extreme ultraviolet lithography which, the company hopes, will achieve feature size objectives, using ultraviolet light with a wavelength of only 13.5 nm, by 2009. (See here.)

That approach, however, is not the only one possible. Other laboratories are claiming features sizes of 26 nm already, using other techniques:

Breakthrough Computer Chip Lithography Method Developed at RIT

Leading a team of engineering students, Bruce Smith, RIT professor of microelectronic engineering and director of the Center for Nanolithography Research in the Kate Gleason College of Engineering, developed a method—known as evanescent wave lithography, or EWL—capable of optically imaging the smallest-ever semiconductor device geometry. Yongfa Fan, a doctoral student in RIT’s microsystems engineering Ph.D. program, accomplished imaging rendered to 26 nanometers —a size previously possible only via extreme ultraviolet wavelength, Smith says. By capturing images that are beyond the limits of classical physics, the breakthrough has allowed resolution to smaller than one-twentieth the wavelength of visible light, he adds.

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Tags: semiconductor fabrication, photolithography, nanolithography, extreme ultraviolet lithography, evanescent wave lithography