Thursday, March 25, 2004

Amusing Personally, I have no use for poetry that doesn't rhyme. Poetry that does rhyme, however, is a different matter. Check out this bit of light verse that I found over at The Leiter Reports. Here's a sample:

Sound Science"

Robert Hanrott
Washington, D.C.

Three hundred years of Western science
Were intended to reduce reliance
On charlatans and superstition
Improving knowledge, health, nutrition.
Humans were expected to progress
Out of an obscurantist mess,
And, alchemy and ignorance spent,
Proceed to their enlightenment,
At a steady but increasing rate.
Our progress seemed inviolate.

On Masticatory Muscle and Encephalization Have a look at this article from today's New York Times. It describes how new research has discovered that a particular genetic mutation may have triggered the evolutionary changes that transformed our ape-like ancestors into Homo sapiens. Here's and excerpt:

At a pivotal time in human evolution, around 2.4 million years ago, a muscle gene underwent a disabling alteration, new research has found. And scientists say this may have made all the difference, leading to the enlarged brains of the lineage that evolved into modern humans.

Researchers who made the discovery said this might be the first recognized functional genetic difference between humans and the apes that can be correlated with anatomical changes in the fossil record. The gene mutation, they said, may amount to the beginning of the ancestral triumph of brain over brawn. At the least, they and other scientists said, the mutated gene probably accounts for the more graceful human jaw, in contrast to apes' protruding jaw and facial ridges.

The discovery was made by scientists at the University of Pennsylvania School of Medicine and is being reported today in the journal Nature. The researchers also described the findings in interviews last week.

``We're not suggesting that that mutation alone buys you Homo sapiens,'' said Dr. Hansell H. Stedman, leader of the research team. But, he added, ``it lifted a constraint" that had inhibited brain growth.''

HLR Update The Washington Monthly has now entered the fray concerning the pro-ID Book Note that appeared in the Harvard Law Review (see my post of March 17), with this blog entry, written by Kevin Drum. Drum's conclusion is clearly stated and right-on:

I've been following the whole thing with one eye, and while I have no sympathy for the ID jihadists I admit that all along I've had a sneaking feeling that, in fact, maybe it really was a bit inappropriate for an influential, tenured law professor to write such a blistering attack on a lowly student. Positions of power and all that, you understand.

Today, though, I finally got around to reading VanDyke's note (warning: large, slow-loading file) and I immediately changed my mind: Leiter probably went too easy on this cretin. Here's the damning sentence:

``...while lumping ID with creationism may be a good rhetorical strategy for ID's opponents, it only detracts from an independent and rigorous evaluation of the merits of ID's claims against those of naturalistic evolution.''

This sentence could be written only by someone entirely ignorant of both the history and substance of ID (which VanDyke surely isn't) or someone who is simply a shill for creationism

And, when it comes to plain truth, clearly stated, it's hard to top this sentence:

What are the actual arguments in favor of ID? The primary one is to accept that science classes are indeed supposed to teach science, but that ID is science. Sadly, though, the scientific community has already passed unanimous judgment on this claim: it's horseshit.

So read the rest of the article.

Wednesday, March 24, 2004

Raining Cats and Blogs Here are two more blogs for you to visit (after getting your daily dose of EvolutionBlog, of course!)

I have previously mentioned (and linked to) Ed Brayton's blog Dispatches from the Culture Wars. He has now started a new blog called The Panda's Thumb which will feature evolution-related posts from a variety of contributors (myself among them!). The name of the blog is borrowed from the title of one of Stephen Jay Gould's essay collections.

Dr. John Lynch of Arizona State University edits Stranger Fruit, yet another welcome addition to the rolls of blogs dedicated to defending science.

Montana on My Mind The Ravalli Republic, a small newspaper serving Western Montana, recently published a pair of editorials on the subject of evolution and ID.

Representing truth and light is Dr. Christopher Cluff, who stepped into the fray with this March 16, article. Here are two excerpts:

Using the same scientific method that allowed these great discoveries and inventions, investigators from the same diverse range of disciplines, often with no idea that their findings might support the concept of evolution, have provided overwhelming evidence that the universe started from a single point in a "big bang" approximately 15 billion years ago, that the earth formed approximately 4.5 billion years ago, that life arose as single-celled organisms approximately 3.5 billion years ago, and that the extremely slow process of natural selection, driven by the ability of DNA to mutate and thereby promote adaptation of organisms to new environments, led to the evolution of a constantly changing variety of highly-specialized species, including humans.

The evidence for these conclusions is not tucked away in some great vault, accessible only to scientists with a secret code; it's available to anyone who is curious and knows how to read. I urge people who think like Andrew Larson, who has expressed his views in this newspaper several times and falsely claims no evidence for evolution exists, to open both books and their minds. The transitional forms they seek have been found in the fossil record in spades and are described in enough books to fill a substantial library.

I would only add that transitional forms in the fossil record are only one of many lines of evidence supporting evolution. It is an especially important line of evidence, given that creationists go to extravagant lengths to deny it.

Regardless of what you believe, public school science class is a place where students should only learn about the scientific method and the information generated by it. The idea that God created the universe is not currently amenable to hypothesis testing, so it remains a belief. Beliefs with no data to support them are religion, not science. Religion, for reasons well understood by our brilliant founding fathers, must remain separate from government (and, hence, the public school system).

That's about as succinct an explanation of what's at stake as I can think of.

Representing darkness and malevolance is Curtis Brickley, who countered Cluff's article with this reply, published on March 18. A typical excerpt:

Recently, Linda McCulloch, our state schools superintendent, was quoted as saying she "criticized the effort" to have "philosophies put into our (Montana's) curriculum."

The question must be asked, "is it philosophy in general that she opposes or is it an opposing philosophy, other than naturalism?"

For example, a local paper quoted Fred Allendorf, University of Montana Professor of Biological Sciences, to say, "As soon as you posit a supernatural move outside the realm of science".

This statement is clearly not based in science but rather in philosophy. Mr. Allendorf is basing his definition of what is or is not science, not on observable data, objectively interpreted, but on a metaphysical assumption that cannot be falsified, tested or observed.

His narrow definition of science is influenced by a philosophical presupposition that "natural" or "material" causes are all that exist. This is the naturalistic approach to science that was criticized by our founding fathers.

If a scientist's observations are subject to his bias and evidence is filtered through the same philosophically biased lens then the conclusions drawn must inevitably reflect the same bias. Therefore, all conclusions drawn must logically be void of any possibility of the supernatural.

As a result we are left not with a "true" search for the truth, but with a modified search, limited within the context of the scientist's definition of truth or within his system of beliefs or philosophy.

Brickley's comments reflect a common misundertsanding of what science is. Like many non-scientists, he pictures science as part of a grand search for truth. Since religious people view the supernatural as an essential part of that truth, any science restricting itself to naturalistic explanations will necessarily be blinkered and incomplete.

People who actually do science for a living have far more practical concerns. Scientists are not paid to promote world views. They are paid to solve problems. Theories that help scientists solve problems survive, while theories that don't help are discarded.

Thus, Mr. Allendorf, quoted in the article, was not making a philosophical presupposition when he said that positing the existence of a supernatural creator is outside science. He was merely observing that it has never once happened that theories based on the supernatural have been helpful in solving actual problems. It is for this reason, and no other, that the supernatural is considered out of bounds among scientists. As soon as someone tells us how invocations of the supernatural will help us solve a problem, they will be embraced immediately.

Science is not primarily about truth. It is about predictability and control. The word ``truth'' has a purely operational definition. A theory is said to be true when it successfully explains so much data and is seen to be so useful that is impossible to deny it. Of course, the simplest explanation for the consonance of theory and data is that the theory is telling us something about the way things really are. That, in itself, is a metaphysical leap, though not one that anyone really feels uncomfortable about making.

Since Mr. Brickley is not a scientist, no one is expecting him to enter a laboratory and come out with the solution to an actual problem. That is why he has the luxury of pontificating about God and philosophy. Let him do some actual research, and then see how long his fondness for the supernatural survives.

Damadian Honored In Monday's posting I reported on the case of Dr. Raymond Damadian, whose work on MRI's in the early seventies was passed over by the Nobel committee. Instead, the prize went to two other researchers, who arguably made more significant contributions in the field.

According to this New York Times article, Damadian has now received an award from the Franklin Institute. This is an annual award given in each of two categories: science and business acumen. Here's an excerpt from the article:

Last fall, Dr. Raymond V. Damadian was denied a Nobel Prize for his role in the development of magnetic resonance imaging. But he won a consolation prize last week, when the Franklin Institute in Philadelphia recognized his business acumen in making the idea profitable.

Dr. Damadian, the president of Fonar Inc. of Melville, N.Y., a manufacturer of M.R.I. machines, complained loudly and publicly after the Nobel Prize in Medicine last year, recognizing "discoveries concerning magnetic resonance imaging," went to Dr. Paul C. Lauterbur of the University of Illinois and Sir Peter Mansfield of the University of Nottingham in England.

In a series of full-page advertisements in The New York Times, The Washington Post and The Los Angeles Times, Dr. Damadian declared that he took the crucial first steps in adapting magnetic resonance for medical scans back in the 1970's and that he should have been recognized for them. The advertisements, which cost hundreds of thousands of dollars, showed a Nobel medal turned upside down and called the omission "the shameful wrong that must be righted."

On Thursday, the Franklin Institute, the science museum in Philadelphia, bestowed one of its two annual Bower Awards on Dr. Damadian. Each year, the awards — one for science and one for business leadership — focus on a different research field. This year, the field is brain research.

Tuesday, March 23, 2004

A Milestone Reached! EvolutionBlog received 142 hits today, as of this writing. This is the first time I have received more than one hundred hits in a day. Thank you to everyone who has stopped by!

Dyson on the Paranormal Don't miss this fascinating article from Freeman Dyson in the New York Review of Books. Dyson is a professor of physics at Princeton University. The book under review is titled Debunked: ESP, Telekinesis and Other Pseudoscience by Georges Charpak and Henri Broch. This book first appeared in French but has now been translated by Bart K. Holland. Charpak is a Nobel laureate in physics.

Dyson's review is highly favorable, and I look forward to reading the book myself. What is especially interesting, however, are Dyson's speculations on the existence of the paranormal.

The hypothesis that paranormal phenomena are real but lie outside the limits of science is supported by a great mass of evidence. The evidence has been collected by the Society for Psychical Research in Britain and by similar organizations in other countries. The journal of the London society is full of stories of remarkable events in which ordinary people appear to possess paranormal abilities. The evidence is entirely anecdotal. It has nothing to do with science, since it cannot be reproduced under controlled conditions. But the evidence is there. The members of the society took great trouble to interview first-hand witnesses as soon as possible after the events, and to document the stories carefully. One fact that emerges clearly from the stories is that paranormal events occur, if they occur at all, only when people are under stress and experiencing strong emotion. This fact would immediately explain why paranormal phenomena are not observable under the conditions of a well-controlled scientific experiment. Strong emotion and stress are inherently incompatible with controlled scientific procedures. In a typical card-guessing experiment, the participants may begin the session in a high state of excitement and record a few high scores, but as the hours pass, and boredom replaces excitement, the scores decline to the 20 percent expected from random chance.

I am among those who believe that anecdotal evidence counts for very little in these matters. A large number of dubious anecdotes does not impress me any more than small number of dubious anecdotes. Elsewhere in the article, Dyson makes it clear that he believes that all attempts to verify paranormal phenomena scientifically have failed.

Dyson suggests that the anecdotal evidence reveals that these phenomena only manifest themselves when people are under stress and experiencing strong emotion. This, he says, is why science has failed to detect them. That is possible, of course. An alternative explanation, however, is that people seem to experience the paranormal at precisely the times when their judgment is most impaired. The anecdotal evidence of people under severe emotional stress is not especially convincing.

Even the most dogmatic skeptic would not assert that paranormal phenomena can not possibly be real. Rather, the assertion is that there is no good reason for believing that they are.

Dyson considers the existence of paranormal phenomena more likely than I do, but I doubt that he is mkaing major life decisions based on this belief. And wherever you come down on this issue, I think all sensible people can agree with Dyson's conclusion:

Whether paranormal phenomena exist or not, the evidence for their existence is corrupted by a vast amount of nonsense and outright fraud. Before we can begin to evaluate the evidence, we must get rid of the hucksters and charlatans who have turned unsolved mysteries into a profitable business. Charpak and Broch have done a fine job, sweeping out the money-changers from the temple of science and exposing their tricks.

Himma on Design Arguments Dr. Kenneth Himma of the University of Washington Department of Philosophy has called my attention to an interesting article he has written about various forms of the design argument for God's existence. The article appears in the Internet Encyclopedia of Philosophy and is available here.

Since contemporary ID theorists rely heavily on dubious probabilistic arguments, I especially appreciated Dr. Himma's lucid remarks on this subject. Here's a sample:

Nevertheless, this more modest interpretation is problematic. First, there is little reason to think that the probability of evolving irreducibly complex systems is, as a general matter, small enough to warrant assuming that the probability of the design explanation must be higher. If having a precursor to an irreducibly complex system does not render the organism less fit for survival, the probability a subspecies of organisms with the precursor survives and propagates is the same, other things being equal, as the probability that a subspecies of organisms without the precursor survives and propagates. In such cases, then, the prospect that the subspecies with the precursor will continue to thrive, leave offspring, and evolve is not unusually small.

Second, the claim that intelligent agents of a certain kind would (or should) see functional value in a complex system, by itself, says very little about the probability of any particular causal explanation. While this claim surely implies that intelligent agents with the right causal abilities have a reason for bringing about such systems, it does not tell us anything determinate about whether it is likely that intelligent agents with the right causal powers did bring such systems about – because it does not tell us anything determinate about whether it is probable that such agents exist. As a logical matter, the mere fact that some existing thing has a feature, irreducibly complex or otherwise, that would be valuable to an intelligent being with certain properties, by itself, does not say anything about the probability that such a being exists.

Accordingly, even if we knew that the prospect that the precursor-subspecies would survive was “vanishingly small,” as Behe believes, we would not be justified in inferring a design explanation on probabilistic grounds. To infer that the design explanation is more probable than an explanation of vanishingly small probability, we need some reason to think that the probability of the design explanation is not vanishingly small. The problem, however, is that the claim that a complex system has some property that would be valued by an intelligent agent with the right abilities, by itself, simply does not justify inferring that the probability that such an agent exists and brought about the existence of that system is not vanishingly small. In the absence of some further information about the probability that such an agent exists, we cannot legitimately infer design as the explanation of irreducible biochemical complexity.

The entire article is rather long, but well worth working your way through.

The Leiter Reports Dr. Brian Leiter, who edits the magnificent blog The Leiter Reports, has seen fit to include a link to this blog in today's entry. Thank you!

Monday, March 22, 2004

Thank You! Blogger Ed Brayton, whose own blog, Dispatches from the Culture Wars is essential reading, was kind enough to mention this blog in his posting for March 21. Many thanks! One small correction though: Mr. Brayton's blog is indeed older than mine. My archive list goes back a long way, but most of that relates to a starter blog called "Science and Politics" that I abandoned about six months before starting this blog. Evolutionblog was started at the end of January.

Is the Nobel Committee Biased Against Creationists? The Nobel Prizes for 2003 were announced recently. Receiving the prize for physiology and medicine were Paul C Lauterbur and Peter Mansfield, of Urbana, IL and Nottingham, England respectively, for their work in Magnetic Resonance Imaging. The official announcement is available here

The controversy is over the exclusion of Dr. Raymond Damadian from this prize. Damadian is often credited as the inventor of the MRI. So why was he not among the recipients?

The Nobel committee is famously secretive about its deliberations, so one can only speculate. And one speculation that's been going around the internet is that Damadian did not receive the prize because of his religious views. Damadian, you see, is a hard-core, young-Earth creationist.

This hypothesis received a major boost from this editorial written by Florida State University philosopher Michael Ruse. For many years now Ruse has been one of the most eloquent defenders of evolutionary theory against creationist attack. He's written dozens of books on this subject, and famously testified on behalf of evolution in the 1981 creationism trial in Arkansas. So if he is jumping on the bandwagon, the charge of religious bias is worth taking seriously. Here's an excerpt from Ruse's article:

But perhaps Dr. Damadian does have reason to feel having been slighted for the wrong reasons. He is not just an inventor, but also a very prominent Christian. And not just a Christian of any bland kind, but a Creation Scientist - one of those people who believes that the Bible, especially including Genesis, is absolutely literally true - six days of creation, Adam and Eve the first humans, universal flood, and all of the rest. It is as least as likely a hypothesis that Damadian was ignored by the Nobel committee because they did not want to award a Prize to an American fundamentalist Christian as that they did not think his work merited the fullest accolade. In the eyes of rational Europeans - and Swedes are nothing if not rational Europeans - it is bad enough that such people exist, let alone give them added status and a pedestal from which to preach their silly ideas. Especially a scientific pedestal from which to preach their silly anti-science ideas.

The trouble is that Ruse presents no actual evidence that Damadian was denied the prize because of his religious beliefs; saying "it is as least as likely a hypothesis" and adding a crude stereotype of Swedish people is not much of an argument. And even a brief look into the history of MRI technology reveals that, in this case, the sinister hypothesis is not necessarily the correct one.

A concise history of this subject is available in this short article from Smithsonian magazine, published in 2000. Here's a quote:

Later that same year, Paul Lauterbur, a chemist and NMR pioneer at the State University of New York, Stony Brook, conceived of a way to use NMR to produce an image. His idea, documented in a notebook, entailed using magnetic field gradients to map out a series of points. In 1973 Lauterbur produced the first NMR image of a small amount of water in a test tube, a feat he published in the journal Nature. Soon after, he imaged the first live subject: a tiny clam.

Though Lauterbur's gradient approach quickly gained favor over Damadian's human scanner method, Damadian filed for a patent on his concept in 1972 and received it in 1974. He forged ahead, determined to make the first human scan. Aided by graduate students, he built the heart of Indomitable, a homemade superconducting magnet, from roughly 30 miles of niobium-titanium wire wrapped on a cylinder. The magnet, a hollow cylinder, spanned 53 inches in diameter, big enough to swallow up a human. On top, the team installed an elaborate liquid helium cooling system to keep resistance in the wire near zero. But the helium leaked miserably, costing $2,000 a week and reducing the magnet's strength.

What seems clear is this: The phenomenon of "Nuclear Magnetic Resonance" (NMR), upon which MRI's are based, has been known since the thirties. Fundamental breakthroughs in the understanding of this phenomenon resulted in a Nobel Prize in Physics for Felix Bloch and Edward Mills in 1952.

Damadian was the first one to realize that this phenomenon potentially had medical applications, and theorized about how this application could be realized. But his approach was fundamentally flawed and impractical. At around the same time Paul Lauterbur developed a far more practical method of using NMR in medical applications, and it is upon his ideas that modern MRI technology is based. Mansfield's contribution was to significantly improve the efficiency and effectiveness of the imaging technology.

So does Damadian deserve a Nobel Prize? I don't know, but the point is certainly arguable. Sure he build the first MRI machine, but he did it using a flawed and impractical design. Many other researchers were working on the same ideas at the time. Damadian's having gotten there first only reflects his willingness to emphasize speed over usefulness and practicality. Yes, he was the first to conjecture that NMR could be used in medicine, but it fell to others to turn that idea into reality. Damadian himself based his speculations upon the work of many others. Perhaps all of them deserve Nobel prizes as well.

As an analogy, the idea of evolution had been proposed several times prior to Darwin, most notably by Jean Baptiste De Lamarck. Darwin is given credit for discovering evolution, however, because it was he who turned it into a workable theory. Lamarack's contribution seems comparable to Damadian's. He had the original insight but was unable to develop it into something workable. Were Nobel prizes given out in those days, I doubt if Lamarck would have received one alongside Darwin.

If it turns out that religious bias really was a factor here, then I would agree with Ruse. Crazy ideas in one branch of science do not negate accomplishments made in other branches. But so far I see no convincing evidence of religious bias.

Sunday, March 21, 2004

The Kitchen Sink One of the standard rhetorical tricks used by creationists to persuade people of the legitimacy of their viewpoint is to throw out, in one breath, an enormous volley of alledged challenges to the theory of evolution. Thus, one second they will be making an argument about thermodynamics, then they will switch gears to anthropology, then to genetics, and on and on. The implication is that if the hapless scientist on the other end of this barrage fails to answer even a single point, then the whole theory of evolution comes crashing down.

This is a fact many scientists have learned the hard way upon accepting debate challenges from creationists. A typical paleontologist, for example, will feel less than comfortable discussing topics in thermodynamics, just as a physicist is likely to be uncomfortable discussing genetics. Their creationist opponent can then make it appear that, in fact, no answer exists to the challenges they raise. Worse, among audiences of non-scientists, this can create the illusion that the creationist knows more than the scientist does.

You see, among serious scientists it is generally considered important to know what you are talking about. Creationists do their work unencumbered by such restrictions.

A classic example of this is the following letter to the editor, which I found at The Helena Independent Record, published on March 15 and available here. I reproduce it here in full:

If evolution is such a certainty, then where did the matter for the singularity of the "Big Bang" come from? Why does our solar system defy the law of conservation of angular momentum? If all of our solar system's planets came from the same cloud of orbiting gas, why are they all so different?

Where did all the water on earth come from? How long does it have to rain on a rock before new life forms? Where did the vast amount of information in the nucleus of the first living cell come from? What led scientists to deceive us with the fraudulent "missing links" Java Man, Piltdown Man, and Nebraska Man?

Why do we find human artifacts in coal beds that are supposed to be millions of years old? Why do we find petrified trees spanning supposedly millions of years of sedimentary strata? How did the Mount St. Helens' eruptions create petrified wood in twenty years? Why are there ancient paintings depicting man with dinosaurs? Why have so many people reported seeing live dinosaurs?

Evolution has no answers for these questions, but the Book of Genesis does: "In the beginning, God created . . ."

Mike Carroll

Mr. Carroll probably fancies himself very knowledgeable on matters scientific, but I fear all he has done is to parrot a lot of objections that other creationists have raised. For example, his opening salvo regarding the Big Bang has nothing to do with evolution, which only explains the development of life once it appears, and not where that life came from in the first place.

I very much doubt that Mr. Carroll could give a coherent description of the law of conservation of angular momentum. Suffice it to say that the solar system does not defy this law (if it did, scientists would not talk about such a law). But even if our solar system were so defiant, it would still have no relevance to evolution.

The irrelevant digression into physics continues with the next objection, that our planets are "all so different." Er, different in what sense? The theory that the planets of our solar system coalesced from the same initial cloud of stellar dust does not imply that the planets so formed must be completely identical. The planets are similar in precisely the ways suggested by this hypothesis, for example, in chemical composition and orbital direction.

Next we come to some silliness about where all the water on Earth comes from, which again has nothing to do with evolution. The idea that rain falling on a rock will eventually produce life is nothing but an absurd caricature of research into the origin of life. Somehow I doubt that Mr. Carroll has made any serious effort to understand this particular branch of science. And, at the risk of repeating myself, none of the objections so far have anything to do with evolution.

Then comes the `fraud' charge. Piltdown man was a genuine hoax, perpetrated in 1912 and discovered in the early fifties. The motives behind the hoax had nothing to do with gulling the public into accepting evolution, and had much to do with the personal glory to the discoverers, coupled with some national pride that would accrue to England for having found its own fossil ancestor (something to match the Cro-Magnon fossils of France and the Neadertals of Germany). It survived as long as it did only because modern dating methods were unavailable at that time. And for much of that time, hominid paleontology was not exactly a going concern. Most scientists at the time met Piltodown man with a shrug. The hoax was eventually exposed by evolutionary biologists who increasingly came to see the Piltdown fossils as a square peg in a round hole. Discoveries made after 1912 started to suggest that the Piltdown fossils showed the wrong amalgam of simian and human features.

Nebraska man was not a hoax, simply an overenthusiastic initial diagnosis of what turned out to be part of a pig fossil. The scientist who made this diagnosis retracted it unreservedly when his error was pointed out to him. This all happened in the nineteen twenties, by the way. I am not sure what fossil Mr. Carroll has in mind when he talks about Java Man.

I doubt he's been keeping up with modern developments in paleontology, but there are now over two dozen known species of hominids known from the fossil record. More are discovered almost daily (see my post for March 4, for example). Does Mr. Carroll think all of them are frauds?

And on and on. So much ignorance packed into one letter. As you can see, I have only written the briefest of replies to these objections, but I have already written far more than did Mr. Carroll himself. Even if I did manage to get through all of them, I'm sure he has dozens more to unload next.

Still, we shouldn't let his final comment go unanswered. He claims that the Bible has the answer to the questions he raises, namely that God created everything. What kind of answer is that? How does that explain where all the water on Earth came from, or where the matter of the universe came from? What does God's creative act have to do with supposed differences in planets or the law of conservation of angular momentum? Nothing that was formerly mysterious becomes comprehensible by invoking God.