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Home country: USA
Current location: Georgia
Member since: Tue Feb 10, 2004, 01:08 PM
Number of posts: 46,462

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Environmental Scientist

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The Life of Pi, and Other Infinities

Published: December 31, 2012

On this day that fetishizes finitude, that reminds us how rapidly our own earthly time share is shrinking, allow me to offer the modest comfort of infinities.

Yes, infinities, plural. The popular notion of infinity may be of a monolithic totality, the ultimate, unbounded big tent that goes on forever and subsumes everything in its path — time, the cosmos, your complete collection of old Playbills. Yet in the ever-evolving view of scientists, philosophers and other scholars, there really is no single, implacable entity called infinity.

Instead, there are infinities, multiplicities of the limit-free that come in a vast variety of shapes, sizes, purposes and charms. Some are tailored for mathematics, some for cosmology, others for theology; some are of such recent vintage their fontanels still feel soft. There are flat infinities, hunchback infinities, bubbling infinities, hyperboloid infinities. There are infinitely large sets of one kind of number, and even bigger, infinitely large sets of another kind of number.

There are the infinities of the everyday, as exemplified by the figure of pi, with its endless post-decimal tail of nonrepeating digits, and how about if we just round it off to 3.14159 and then serve pie on March 14 at 1:59 p.m.? Another stalwart of infinity shows up in the mathematics that gave us modernity: calculus.

“All the key concepts of calculus build on infinite processes of one form or another that take limits out to infinity,” said Steven Strogatz, author of the recent book “The Joy of x: A Guided Tour of Math, From One to Infinity” and a professor of applied mathematics at Cornell. In calculus, he added, “infinity is your friend.”



On the "Debt Ceiling"

2 things. One, I just don't see how Obama is the one under pressure here. It will be up to the House and Senate to pass a debt ceiling bill, and so far the House, at least, is so screwed up I can't see them actually agreeing to anything other than a straight pass. They really, really want to make Obama push for republican policies, and he is not going to do it (based on the fiscal cliff bill just worked out). Hell, I think they just want to vote no on everything.

Now, if one really wanted to make the t-baggers heads explode, what if the Fed just started printing money to cover the deficit when the ceiling is reached. Or threatened to. Yes, it would cause inflation, but not immediately, and it would cause all sorts of freakouts on the far right. In any case Obama should do what Clinton did, shut down the government when the ceiling is reached and let the repubs in the house take the blame.

Replica of Michelangelo's David has penis cut off

A reproduction of Italian renaissance artist Michelangelo's masterpiece, "David," has been attacked by a group who cut off its penis, daily Hürriyet has reported.

The statue, a reproduction by renowned German sculptor Hans Peter Feldmann in the Kant park of the western German city of Duisburg, has been taken to an atelier for restoration following the attack.

David is a 5.17-meter marble statue of a standing male nude, representing the Biblical hero David. The original David, which was created between 1501-1504, is exhibited in Academy of Fine Arts in Florence.

Obituary: Rita Levi-Montalcini

Nobel Prize-winning neurobiologist Rita Levi-Montalcini died on Sunday, December 30th in Rome, at the age of 103. Levi-Montalcini shared the 1986 Nobel Prize for Medicine, for her contribution to the discovery of nerve growth factor. Her work gave profound insights into how the nervous system regulates the number and growth of cells during its development, and opened up hopeful avenues of research into cancer, embryology, nerve regeneration and neurodegenerative diseases which continue to this day.

Levi-Montalcini began her illustrious career in the face of huge adversity. Born into a wealthy Jewish family in Turin, she studied medicine despite her father's opposition, and upon her graduation in 1936 decided to pursue a career in research. By then, the Nazis had introduced laws that banned Jews from practicing medicine and taking academic positions. Nevertheless, she set-up a makeshift laboratory in her bedroom at her parents' Turin home and, risking imprisonment or death, performed her experiments in secret. But she aroused little suspicion buying the fertile eggs needed for her research and, furthermore, the remnants of her experiments could usually be eaten afterwards.

The story of nerve growth factor began in the 1940s, when Levi-Montalcini replicated the experiments performed by Viktor Hamburger, an embryologist at Washington University in St. Louis. Working in her bedroom, using microsurgical and tissue manipulation equipment fashioned out of sewing needles and watchmaker's tweezers, she removed the limb buds from chicken embryos, and found that this led to a reduction of the number of motor neurons in the corresponding region of the spinal cord. Conversely, grafting supernumerary limbs onto the embryos resulted in a greater number of spinal motor neurons.

Hamburger had obtained the same results a decade earlier, and had hypothesized that the limb buds contain a substance that directs immature nerve cells to differentiate into motor neurons. Levi-Montalcini interpreted the data differently – she argued instead that the substance in the limb buds promotes the survival of the newborn cells. Her research was cut short by the Nazi occupation, however, which forced Levi-Montalcini to go into hiding until 1944. After a brief stint as a doctor-cum-nurse in the Allied refugee camps, she returned to Turin University as soon as the war ended to resume her research. A year later, Hamburger invited her to join him in St. Louis. Hamburger had asked her to join him for a few months, but she ended up staying 30 years.


Odd sand dunes left after Hurricane Sandy

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