Saturday Jul 14, 2007
Tuesday Jun 12, 2007
By MortazaviBlog on Jun 12, 2007
In the modern, high-pressure work environment of places like the Silicon Valley, many of us work hard and sleep little. People often speak of "making up" lost sleep, but Charles A. Czeisler, sleep and fatigue researcher at Harvard Medical School, reminds us that potential to sleep only grows with every waking hour (HBR, Oct. 2006):
Most of us think we're in control of sleep -- that we choose when to go to sleep and when to wake up. The fact is that when we are drowsy, the brain can seize control involuntarily. When homeostatic pressure to sleep becomes high enough, a couple of thousand neurons in the brain's "sleep switch" ignite, as discovered by Dr. Clif Saper at Harvard Medical School. Once that happens, sleep seizes the brain like a pilot grabbing the controls. If you're behind the wheel of a car at that time, it takes just three or four seconds to be off the road.
So, getting enough sleep should become a high-priority commitment.
Saturday Feb 03, 2007
By MortazaviBlog on Feb 03, 2007
Intergovernmental Panel on Climate Change was set up by WMO and UNEP to "assess scientific,
technical and socio- economic information relevant
for the understanding of climate change, its potential
impacts and options for adaptation and mitigation." The fourth assessment of the IPCC will be released under Climate Change 2007. You can also consult IPCC's February 2, 2007 Paris conference webcast for a preview.
These assessment reports do not come out haphazardly. The third assessment was called Climate Change 2001. So, 6 years of further work and data has gone into the new assessment.
Average temperatures could increase by as much as 6.4C by the end of the century if emissions continue to rise, with a rise of 4C most likely, according to the final report of an expert panel set up by the UN to study the problem. The forecast is higher than previous estimates, because scientists have discovered that Earth's land and oceans are becoming less able to absorb carbon dioxide.
You can also listen to Guardian's interview with its reporter, Mr. Adam.
The working group has made available The IPCC Working Group I Fourth Assessment Report Summary for
Policymakers (SPM). Page 15 of the report contains green house gas concentration measures based on examination of ice-core going back to 10,000 years.
Tuesday Aug 22, 2006
Monday Apr 10, 2006
By MortazaviBlog on Apr 10, 2006
Finally, in part 3, I discuss the big freeze and what scientists now see as the end of our universe. I also give a serious though speculative, discussion of how an advanced civilization in the distant future might use the laws of physics to leave our universe trillions of years from now and enter another, more hospitable universe to begin the process of rebirth, or to go back in time when the universe was warmer.
From the preface of Parallel Worlds by Michio Kaku.
The very idea of parallel universes was once viewed with suspicion by scientists as being the province of mystics, charlatans, and cranks. Any scientist daring to work on parallel universes was subject to ridicule and was jeopardizing his or her career, since even today there is no experimental evidence proving their existence...But recently, the tide has turned dramatically, with the finest minds on the planet working furiously on the subject.
From chapter one of Parallel Worlds by Michio Kaku.
Monday Jan 09, 2006
By MortazaviBlog on Jan 09, 2006
Last Thursday, my family and I went to a Chinese restaurant recommended by my daughters' piano teacher.
We ordered a course for four, and I chose a mushroom dish as one of the four dishes which we could order as part of the deal but I didn't touch the mushrooms until my wife served me a large piece of the top, which looked like two round pieces attached together. I ate it with little thought but in about half-an-hour, I experienced an amazing, almost overwhelming change. After a long, tiring day, I had suddenly become more clear and alert. My eyes, which are usually equiped with glasses, seemed to be viewing a further and wider scope, and I seemed to be present in the moment with a pleasant sensation throughout my body. When I talked about this to my wife and daughters, they dismissed it with a laugh but after some insistence on my part, we started looking at the table to search for what had affected me. Other than the duck tongues, I had had everything else before in some setting. The only thing new was the mushrooms. We summoned the floor manager, and asked him about the mushrooms.
And this morning, just before departing home, I spotted a Wall Street Journal article on Dr. Akira Endo, a Japanese scientist who has cultivated fungi for their medicinal, anti-cholesterol and other effects since the 1960s. ("Stalking Cholesterol: How One Scientist Intrigued by Molds Found First Statin — Feat of Japan's Dr. Endo Led To Heart-Care Revolution But Brought Him Nothing — Nature as a Drug Laboratory" Peter Landers, WSJ, January 9, 2006; Page A1.)
Returning to Reishi, much useful information can be found on the web. For example, see references by Dylan Kosma and Daniel J. Royse. It is also mentioned by the Taoists as the "Elixir of Life". People interested in Reishi might also be interested in Lichens. UC Davis, where I spent 7 years doing graduate work, offers a course in edible mushroom cultivation.
Friday Oct 28, 2005
Wednesday Sep 21, 2005
By MortazaviBlog on Sep 21, 2005
In the next few days, you should be able to view Hurricane Rita off the Gulf Coast on the satellite images available at the website of National Oceanic and Atmospheric Administration's Weather Service. (Click the "Satellite" tab on that website.) The image below may or may not have Rita on it depending on when you visit. There are a great number of other fantastic atmospheric images provided by NOAA. To me, it all shows the amazing power of the earth and its atmosphere. In a multitude of ways, the earth seems like a living creature and it might be understood far better if viewers saw it in those terms.
By the way, in case you're wondering why I've written so much about hurricanes, I should add that I have more than just a common curiosity that moves with the news. After all, a good portion of my engineering Ph.D. dissertation (completed in 1989-1990) was devoted to the theoretical and computational study of vortex-vortex interactions at high Reynolds numbers.
Tuesday Aug 30, 2005
By MortazaviBlog on Aug 30, 2005
At the end of his little book On the Internet, one of the leading contemporary philosophers, Hubert Dreyfus, laments
In sum, as long as we continue to affirm our bodies, the Net can be useful to us in spite of its tendency to offer the worst of a series of asymmetric trade-offs: economy over efficiency in education, the virtual over the real in our relation to things and people, and anonymity over commitment in our lives. But, in using it, we have to remember that our culture has already fallen twice for the Platonic/Christian temptation to try to get rid of our vulnerable bodies, and has ended in nihilism. This time around, we must resist this temptation and affirm our bodies, not in spite of their finitude and vulnerability, but because, without our bodies, as Nietzsche saw, we would be literally nothing. As Nietzsche has Zarathustra say: 'I want to speak to the despisers of the body. I would not have them learn and teach differently, but merely say farewell to their own bodies—and thus become silent.'
Simpler (possibly indirect) indications of these claims are scattered everywhere for us to see. For example, consider this little note on the importance of physical being and exercise to the health of one's memory, the quintessential aspect of mind, or read the report in today's Wall Street Journal on "Exploring the Bicycle-Brain Connection: How Exercise Boosts Cognitive Function." (The Journal requires a paid subscription for access to its online edition.)
Of course, examples such as these are simply reminders of something more significant. What Dreyfus says in his various writings, including those on Heidegger and on artificial intelligence, is actually much deeper. The claim is that the understanding of (and coming to terms with) our status in the world is impossible without our physical interaction and being in it. In fact, there is a tight connection between the two. For example, we learn quite differently (in quality and experience) as we shake a hand in a meeting room, leaf through a book on a coach or write in a note book under a tree using the pen held by our fingers than when we do something similar to all these things through the use of different physical environment such as the screen of a VDT, a mouse and a keyboard. The state of physical being and the form of interaction is actually not immaterial despite what some might like to think.
Monday Aug 22, 2005
By MortazaviBlog on Aug 22, 2005
Xiaoyun Wang is the lead author of a recent paper on a new attack on SHA-0 (and others regarding similar methods of attack on SHA-1). John Markoff of The New York Times tells the story of how she was unable to make it to the Crypto 2005 conference due to visa restrictions that slowed her application.
Friday Aug 19, 2005
By MortazaviBlog on Aug 19, 2005
Yesterday, I wrote a little entry on jet lag prevention.
Genome Informatics ( 15(1): 3-12 (2004)) has published an interesting paper by researchers at Humboldt University, Berlin, on the cricadian oscillator, or the biological clock of mammals (Becker-Weimann, S., Wolf, J., Kramer, A. and Herzel, H. "A Model of the Mammalian Circadian Oscillator Including the REV-ERBα Module").
In the introduction to the paper, we read:
It was interesting to me that jeg lag actually manifests in the body through the autonomous oscillations in proteins and mRNA concentrations. This paper points to other research that examine "extensive and divergent circadian gene expression in liver and heart" (Nature, 417:78-83, 2002).
The paper also points to a book, by Leon Glass and Michael C. Mackey, which seems worth a thorough study: From Clocks to Chaos: The Rhythms of Life. In fact, I think I'll be ordering it very soon as the topic continues to fascinate me whether it concerns the importance of certain temporal rythms in religious rituals or my own personal experience and scientific background.
One thing I've noticed in my personal life. In the last five years, my family and I have travelled across 11 to 12 time zones and back, every summer, and I've observed that my youngest daughter has always taken the longest to get over her jet lag and that the older members of the family have suffered from more severe lingering oscillations in attempting to re-adjust their biological time.
For those interested in further study, McGill University hosts a multi-university Center for Nonlinear Dynamics in Physiology and Medicine.
Tuesday Jan 18, 2005
By MortazaviBlog on Jan 18, 2005
Cornell University researchers have released a video rendition of a numerical simulation for the recent Indian Ocean Tsunami of December 26, 2004:
According to Cornell's news release:
Thursday Jan 13, 2005
By MortazaviBlog on Jan 13, 2005
The BBC reports today of the effect of 3 meter high tsunami waves as far away as the fishing settlement of Hafun, in north-east Somalia, which is located more than 7,000km (4,000 miles) from the epicenter of the earthquake.
University of Alaska, Fairbanks, has a short note on tsunami waves and the factors affecting their rate of travel and dispersion. However, the focus of this elementary note is on storm-generated waves.
The University of Washington, Seattle, maintains a page on general tsunami information, including a multi-media documentation of recent tsunami events, but no readily available information appears there for calculating the speed and rate of dispersion from a single observation of the wave at a known distance form the epicenter. From what I know about the physics of water waves it should be possible to come up with rough but very useful speed and dispersion estimates based on such (single point w.r.t. epicenter) information. There is a link to tsunami research centers in the U.S. which I didn't have time to pursue in detail.
The USC Tsunami Research Center seems to be the most web-friendly and promising online source of material on tsunami research. It is worthy of further exploration. See, for example, video clips of some simulations for a tsunami event off the coast of California. (If the video simulations included wave amplitude and time progression (or relevant non-dimensional numbers), some non-dimensional analysis could allow rough extensions to similar cases.) Some of the research publications of this center on the analytics of tsunamis should be useful for extracting a simple model to compute speed and dispersion rates. For example, this paper may be start but it considers the case of shallow water wave amplitude evolution. The reference in the paper to "Lamb" is probably to Sir Horace Lamb's seminal work Hydrodynamics of 1879, chapter VIII of which is devoted to the analytical study of tidal waves of various kinds. (I believe Ludwig Wittgenstein studied with Sir Lamb before starting his work with Bertrand Russell.)
While the more fancy analytics and high-compute simulations taking account of coast-line land formations may be of great interest to property insurers and pure scientists, conservative back-of-the-envelope estimates for speed and dispersion of tsunami should still be possible for any middle-schooler to perform and for any fluid dynamics student to explain.
Friday Oct 15, 2004
By MortazaviBlog on Oct 15, 2004
Tuesday Sep 07, 2004
By MortazaviBlog on Sep 07, 2004
Inventions in science and technology are not all about progress.
Every technical invention seems to take something from us in return for what it gives.
With the invention and propagation of basic electric lighting, ultimately brought to every office and home in every city and small town, something sacred was taken from most people--a serene night's sky, which most urbanized people can now see only through the sanitized and limited version that comes to them as images telescopes have viewed, processed and recorded according to their own limitations.
No longer do we need to feel, on a nightly basis, a deep wonder about our place in the universe. The problem has been solved and put to rest.
Saturday Jul 03, 2004
By MortazaviBlog on Jul 03, 2004
The 3-D structure of proteins determines their biochemical operation.
For example, a great deal of effort was used to map the 3-D structure of Hemoglobin, the main ingredient of our red blood cells, in order to discover and explain how it fixes oxygen.
Computer visualization is only one aspect of structural analysis. In fact, it is one of the last steps in the the geometric analysis of a protein. (The ultimate goal being the actual biochemical function and relationships.)
Another important (and more fundamental) aspect is the actual determination of the geometric structure given a protein's amino acid sequence.
Such determination involves an optimization problem which searches for geometric positioning of protein backbone such that the lowest potential energy state is attained.
This procedure follows from the basic physical principle that all structures prefer the geometry that leads to the lowest potential energy.
The potential engergy can be determined by adding all potential energies due to interactions among the amino acid molecules that have been strung together in a protein.
There is a whole separate art in writing the potential energy equation as a function of molecular positioning and solving it for its lowest value in the hyperdimensional space of the molecular distances. The optimization problem can be solved in a number of ways. Since this is a large-dimension problem, it is important to use some heuristics to start the problem with the protein geometry in a realistic initial state. Following this initial state, the computation searches for neighboring states that have lower potential energy. This sequence is repeated until lowest potential energy "neighborhood" in the hyper-dimensional space of molecular distance vectors is found.
Saturday Jun 26, 2004
By MortazaviBlog on Jun 26, 2004
There were many German entries, and the first winners come from Osnabruck, Germany, the city of my sister-in-law's family.
RoboCup itself is a larger organization.
At one point, when I was studying with Hubert Dreyfus, I planned to write an essay on whether it was possible for robots to play real soccer.
Well, here is RoboCup's goal: By the year 2050, develop a team of fully autonomous humanoid robots that can win against the human world soccer champion team.
It's a lofty goal, and to what degree it will be accomplished is worth watching.
Unless the robots are allowed to injure people, I doubt they'll win . . .
Now, it is time for me to run for my weekend soccer game on the Stanford compus!
Have a wonderful JavaOne and watch for those robots and don't let them beat you ! ! !
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