ILL/Melvyl Requests

If you request materials using Melvyl or Citation Linker over the holidays while off-campus, you may experience technical difficulties. The UCSD proxy server cannot process these requests correctly and it may not be fixed until January 2. If you’re using VPN instead of the proxy to access library resources, you should have no problems.

Alternate ways to send in your requests over the break:

• Use the S&E ILL request form at http://gort.ucsd.edu/MINES/request.html
• Send your request by email to scilib@ucsd.edu. Include your name, dept/major, ID barcode, and the citation for the item(s) you need.

And not matter how we get your requests, they will be processed in the order received when we reopen on Wednesday, January 2.

Knot Physics - NYT

In the New York Times Magazine’s annual Year of Ideas issue, one of the 70 honored ideas comes courtesy of UCSD: Knot Physics. Assistant Professor Douglas Smith and undergraduate Dorian Raymer were also profiled in this week’s UCSD News about their work on knot formation.

Among the other honored ideas: the Radiohead payment model, Wikiscanning, the Biofuel Race, and Wireless Energy.

Spontaneous knotting of an agitated string
Dorian M. Raymer and Douglas E. Smith
PNAS | October 16, 2007 | vol. 104 | no. 42 | 16432-16437

It is well known that a jostled string tends to become knotted; yet the factors governing the “spontaneous” formation of various knots are unclear. We performed experiments in which a string was tumbled inside a box and found that complex knots often form within seconds. We used mathematical knot theory to analyze the knots. Above a critical string length, the probability P of knotting at first increased sharply with length but then saturated below 100%. This behavior differs from that of mathematical self-avoiding random walks, where P has been proven to approach 100%. Finite agitation time and jamming of the string due to its stiffness result in lower probability, but P approaches 100% with long, flexible strings. We analyzed the knots by calculating their Jones polynomials via computer analysis of digital photos of the string. Remarkably, almost all were identified as prime knots: 120 different types, having minimum crossing numbers up to 11, were observed in 3,415 trials. All prime knots with up to seven crossings were observed. The relative probability of forming a knot decreased exponentially with minimum crossing number and Möbius energy, mathematical measures of knot complexity. Based on the observation that long, stiff strings tend to form a coiled structure when confined, we propose a simple model to describe the knot formation based on random “braid moves” of the string end. Our model can qualitatively account for the observed distribution of knots and dependence on agitation time and string length.

Finals Hours

Just a reminder that S&E has gone to extended hours for finals.

Sat (12/8) , 10am - 1:45am
Sun (12/9), 10am - 1:45am
Mon (12/10), 10am - 1:45am
Tues (12/11), 10am - 1:45am
Wed (12/12), 10am - 1:45am
Thurs (12/13), 10am - 1:45am

And don’t forget: CLICS is open 24/7 until Thursday.

UCSD, SciVee and CNN

This week, CNN posted an article (via AP) on their website about SciVee, focusing on how Haim Weizman (Chemistry) is using the site to demonstrate organic chemistry laboratory techniques.

Launched this summer by UCSD pharmacology professor Phillip Bourne with funding from NSF, SciVee can best be described as “Science meets YouTube.” Scientists can upload videos and pubcasts, which are then freely available for viewing by anyone.