Slashdot Mirror

The Hong and Mirkin reference is:
S. Hong and C. A. Mirkin, "A Nanoplotter with Both Parallel and Serial Writing Capabilities", Science 288(5472):1808-11 (9 Jun 2000).

You can download a PDF version of the paper (without registration) from here
- El Nino

Wow, do us a favor and don't link to articles that ask for money to read them. The NYT sign up thing I can deal with. But $5 for temporary access to one article? No thanks.

-Waldo

OTOH, listen to the voice of the scientific majority. In it you will hear a relatively conservative, guarded discussion of global warming. Yes, there will be a vocal minority of scientists who put forth outlandish hypotheses, but the consensus of the others will return the debate to more solid ground.

There will be a report on global warming issued this year by an international multidisciple group of scientists. These reports come out every five years. Unless the politicians intervene, this report will state that human activity is having a discernable affect on global temperature increase. This plot shows measured and computed global temperature for the past 1000 yrs. I find it scary.

Then there are the computer simulations that attempt to model and reproduce the various observations.

Please note, these types of research are relatively independent of each other. After decades of work, the diverse set of results are starting to reach one strong conclusion. There will be an United Nations sponsored report due out at the end of the year by the Intergovernmental Panel on Climate Change. Currently in draft form, this report will state, "there has been a discernible human influence on global climate." Remember scientists are conservative in stating their conclusions. This is in reality, a very strong statement.

A short review of this report was presented in Science. Please check out the figure showing temperature fluctuations over the past 1000 years. If this doesn't scare you, nothing will.

Then there are the computer simulations that attempt to model and reproduce the various observations.

Please note, these types of research are relatively independent of each other. After decades of work, the diverse set of results are starting to reach one strong conclusion. There will be an United Nations sponsored report due out at the end of the year by the Intergovernmental Panel on Climate Change. Currently in draft form, this report will state, "there has been a discernible human influence on global climate." Remember scientists are conservative in stating their conclusions. This is in reality, a very strong statement.

A short review of this report was presented in Science. Please check out the figure showing temperature fluctuations over the past 1000 years. If this doesn't scare you, nothing will.

Heres another interesting article from science magazine. It provides an overview of the experts estimates of when oil production will peak.

Do you have any references for the scientists you speak of? As far as I know all oil is created deep within the earth - but it is reliant on the decomposition of organic matter. There is a lot of biomass stretching miles beneath the earths surface but the problem is TIME. I don't doubt that with a functioning biosphere the organic processes that lead to oil production would continue. This could lead to replenishment in geological timeframes (i.e. hundreds of thousands of years). This will not be of benefit to our current civilization. Also note functioning biosphere! I found an article in science magazine(subscription required for full text) which discusses the latest US Geological Survey assessment of global oil reserves. The main points they make are 1. that they expect world oil production to peak around 2015-2020. 2. the experience of production in the US is that improving technology will not be able to halt the decline once the peak is reached.

(Why is that? Everyone know that static energy is actually a form of electricity. And electricity produces heat when it moves, thus causing the interior of the computer case to heat up. See Jager et. al -- subscription required, sorry.)

You may laugh this off as excessive worrying, but this is a serious problem. I've overclocked a few chips, and they've all died pretty quickly -- and that was without static RAM. High-powered memory zapping around would kill the chip even more quickly. And what if that chip is powering some mission critical application like a space shuttle flight or an air traffic controller?

Just my two cents,
- vl

I am one of the authors of the work that Geoff Ozins techniques are based on (Synthesis of Macroporous Minerals with Highly Ordered Three-Dimensional Arrays of Spheroidal Voids. Holland, B.T.; Blanford, C.F.; Stein, A. Science 1998, 281, 538-540 [Abstract] and Synthesis of highly ordered, three-dimensional, macroporous structures of amorphous or crystalline inorganic oxides, phosphates, and hybrid composites. Holland, B.T. et al. Chem. Mater. 1999, 11, 795-805 [Abstract]).

In addition to the technological limitations of photonic computing, we are a long way from fabricating these materials on a length scale that will work for even a rudimentary application, such as a waveguide. As the article states on the first page, their silica structure has "a typical single domain size of 100 um". The templates are brittle (they are essentially artificial opals) and the defect control is nearly impossible. Defects in the material grossly affect the behavior, that is, whether they behave like a photonic band gap material or a waveguide or whatever.

I think another promising route that isnt mentioned here is covered in Fabrication of photonic crystals for the visible spectrum by holographic lithography Nature 2000, 404, 53-56 [ Abstract. Free registration required]. Rather than using an opal for a template, they have complete control over the shape of the void lattice by the holographic interference of several lasers in a polymer matrix which is replaced by a high refractive-index semiconductor.

I think you have a problem understanding what "theory" means, scientifically and philosophically speaking, otherwise you wouldn't be talking about proving one or the other. You see, scientific theory, according to scientific methodology widely accepted and developed by Karl v. Popper and later his follower Imre Lakatos has to be a) falsifiable (within the limitations given by Lakatos) b) has to have explanatory power (that is, has to predict further facts) c) has to provide you with a sound scientific programme. Sound means, ehem, it means "interesting" --- for example, collecting and naming all the bugs from planet Earth is of course a scientific programme, but a rather boring one, and it will not provide any further insight into how the things work. However, collecting those bugs in terms of researching biodiversity, and looking at ecological mechanism which drive biodiversity, can be a sound scientific programme. You have to start thinking first, developing a model or a hypothesis you will test, and collect only the data you need.

I will not explain here why a theory cannot be proven, but only refuted --- I would be very disappointed if the readers of Slashdot couldn't think of an explanation.

It is true, that people speak of widely accepted theories as facts, and I agree fully with you that it is not good. It keeps people from being ingenious and thinking on their own. However, I'm a molecular biologist trained in evolution and experimental evolution and from my experience, creationism fails to be a theory in all the three points I mentioned. It is boring (you can explain anything by miracles, and there is no place for thinking), it is non-falsifiable, and it does not make any sound predictions. But let's not start a creationism v. evolution debate here, please. There are better places on the Net to do so. Allow me only one more thing to add: "theory of evolution" is a somewhat inadequate term. One can think of many theories trying to explain what we observe and call the process of evolution, that is a change of biological diversity through time. The Modern Synthesis (or "neodarwinism" or "Synthetic Theory of Evolution, STE") is only one of them --- it is accepted by the scientist, because it works well and there are no alternatives. However, we (the biologists) still try for better things. Science is about trying out things, hacking the Nature, doubting everything. STE has still it's problems, for example (even with the recent Nature publication) the origin of two sexes. (No, origin of life isn't IMHO one of those grand problems: you see, we can think of some ways life could have arisen: the problem is, there is no way we can trace it back. Even if humans create artificial life, it will be only a prove that it can be made in this and this way, and not, that it really happened like this. History is not a science in terms of Popper).

All current theories have it flaws and problems, and I think they always will (here I differ in my view with Horgan, who boldly announces "The end of science"). What was not mentioned in the Slashdot review and not adequately stressed in the referred article is that the point is not in discovering an old meteorite! The point is, they have created a model of solar nebula formation, a theory, and they have supported it with experimental evidence, which was contradictory with the current models. And this is precisely the point I wanted to make: science is not about discovering things or facts, but creating theories and models which provide us with explanations and predictions.

Here is the reference to the original Science article: http://www.sciencemag.org/cgi/content/short/288/54 67/839.

Best regards,

January

In fact, as it happens, LOCKSS is being worked on in association with HighWire Press at Stanford (disclosure: also my employer :), which publishes the online versions of nearly 200 major scientific journals and has a _very_ good relationship with a large number of publishers. They also list the Journal of Biological Chemistry and Science Online as "partners".

I wouldn't be so quick to dismiss the interest that the non-profit academic societies have in preserving this information.

Then there is the news article in Science, plus the actual report itself; both of these are available to the general public, unlike much of the (subscription only) journal.

---

Then there is the news article in Science, plus the actual report itself; both of these are available to the general public, unlike much of the (subscription only) journal.

---

Lars
__

For those interested in Penrose's theories of the mine, here's an interesting article you may be interesting.

From Science Volume 287, Feb 4, 2000, p 791:

NEUROSCIENCE: Cold Numbers Unmake the Quantum Mind
Charles Seife

"Calculations show that collapsing wave functions in the scaffolding of the brain can't explain the mystery of consciousness."

"Sir Roger Penrose is incoherent, and Max Tegmark says he can prove it. According to Tegmark's calculations, the neurons in Penrose's brain are too warm to be performing quantum computations--a key requirement for Penrose's favorite theory of consciousness."

From farther down in the article...

"Combining data about the brain's temperature, the sizes of various proposed quantum objects, and disturbances caused by such things as nearby ions, Tegmark calculated how long microtubules and other possible quantum computers within the brain might remain in superposition before they decohere. His answer: The superpositions disappear in 10-13 to 10-20 seconds. Because the fastest neurons tend to operate on a time scale of 10-3 seconds or so, Tegmark concludes that whatever the brain's quantum nature is, it decoheres far too rapidly for the neurons to take advantage of it."

As it was mentioned by other /.ers here, this is real cloning, because cloning, in generally, means "getting something genetically identical". In especially, in molecular biology you often say about "cloning a gene", which has less in common with getting a dozen of Einsteins out of a bunch of Einsteins' hair.

The goal of the study was twofold. First, it is the first time a nonhuman primate clone was obtained. Second, the idea is of making a large scale experiment to look for possible abnormalities and/or distortions of resulting clones, as well as differences among them.

Another question was, at what stage of development is it safe to do the embryo splitting, e.g. is it possible to get a 32 cell embryo and divide it into 32 single cells, each resulting in a viable embryo?

The authors did not answer all the question fully, they rather prepared the ground for research yet to come. There are a lot of things to test, the goal not being necessarly cloning of humans (or even monkeys) itself, but rather basic research on development of primates and establishing cultures of embryonic cells (which are, as you know, very useful, because they are able to develope into any mature cell of a given organism).

Of course, getting genetically identical monkeys for drug research is also an issue, although I personally consider research on monkeys very questionable. Chimpansees are much more close to humans then most of the people think - if you haven't read any of Jane Goddals books on chimpansees, do not answer to this point of my reply. What I want to say is that I consider it to be more human to do the phase I drug research on human volunteers, yes, or even humans which are forced to do so - but are conscious of what is happening to them. Doing experiments on chimpansees is something like doing research on children for me.

Regards,

j.

"Self-similarity in the distribution and abundance of species", J.Harte, A. Kinzig, J.Green, Science 284 334 1999

Things aren't quite as bad as you imply with fMRI Nick; there's been a lot of work about this in the last ten years!

Optical imaging experiments show how you can use direct observation of the brain to interrelate the changes seen with fMRI and neural activity. There are many more similar studies, all of which suggest a close correlation between neural activity and fMRI measurements. More recently people have begun comparing similar paradigms directly in macaque and human using fMRI and electrophysiology

Geraint
geraint@klab.caltech.edu

Anyhow, AAAS publishes Science, one of the long time standing top scientific journals, which has on occasion published bad science. While 90% to 99% of the submissions are top notch, bleading edge, Science is not definitive (Check the frequently quoted thing on global warming Rush L. loves to quote, but was later retracted). And Science has been pushing a lot of internet stuff lately, and my honest opinion is none of it is the quality of research that they publish on biology or environmental issues or other "true" sciences.

Sorry, I don't intend this to be a flame, but is the internet really a "science" like physics, chemistry, biology, and the likes? I do NOT think so. Because you can apply a scientific method to study internet traffic does not make the internet itself a science. In the defence of the internet, something doesn't have to be a science to be important, not much that goes on on Wall Street, or in Washington D.C. is "science" either, but it can be studied with a scientific method.

My opinion is Science (the journal) needs to get the heck out of "internet studies" and leave it to the people who do IT full time. I think a few of the editors are just feeling a little to "empowered" with thier publishing athority and making themselfs look a bit silly now that they figured out how to take a screenshot and get it published to a wide audiance... (So, in other words, I don't care WHAT they say at the AAAS about the net. They are important to the community of science, but they are out of thier element when when it comes to IT)

Actually, this is what ZDNet was talking about. Note that three authors are from IBM: Science Aug 6 1999: 864-867

Minimum Field Strength in Precessional Magnetization Reversal

C. H. Back, 1* R. Allenspach, 2 W. Weber, 1 S. S. P. Parkin, 3 D. Weller, 3 E. L. Garwin, 4 H. C. Siegmann 1

1 Laboratorium für Festkörperphysik, ETH Zürich, CH-8093 Zürich, Switzerland.
2 IBM Research Division, Zurich Research Laboratory, CH-8803 Rüschlikon, Switzerland.
3 IBM Research Division, Almaden Research Center, 650 Harry Road, San Jose, CA 95120, USA.
4 Stanford Linear Accelerator Center, Stanford University, Stanford, CA 94305, USA.

Ultrafast magnetic field pulses as short as 2 picoseconds are able to reverse the magnetization in thin, in-plane, magnetized cobalt films. The field pulses are applied in the plane of the film, and their direction encompasses all angles with the magnetization. At a right angle to the magnetization, maximum torque is exerted on the spins. In this geometry, a precessional magnetization reversal can be triggered by fields as small as 184 kiloamperes per meter. Applications in future ultrafast magnetic recording schemes can be foreseen.

The article is in the July 16 issue of Science, titled "Electronically Configurable Molecular-Based Logic Gates".

Here's the abstract:

Logic gates were fabricated from an array of configurable switches, each consisting of a monolayer of redox-active rotaxanes sandwiched between metal electrodes. The switches were read by monitoring current flow at reducing voltages. In the "closed" state, current flow was dominated by resonant tunneling through the electronic states of the molecules. The switches were rreversibly opened by applying an oxidizing voltage across the device. Several devices were configured together to produce AND and OR logic gates. The high and low current levels of those gates were separated by factors of 15 and 30, respectively, which is a significant enhancement over that expected for wired-logic gates.

If you have an online subscription to Science, you can pull off the full text of the article here

See also:
http://www.newscientist.com/ns/9 81107/nshorts.html for a short note about the paper published in Science (Search for Benzer, free registration needed to read the abstract).

There is also a fantastic article on Seymour Benzer in the April 5 issue of the New Yorker.

--Bob