" organized contacts " at the interfaces of physical contact between T cells and APCs (Monks et al., 1997). areas between T cells and APCs incubated with anti-genic peptides indicate that a SMAC is organized into Stanford, California 941010-0269 distinct spatial domains (Monks et al., 1998). The central area of a SMAC contains the TCR, CD3, p56 lck and p59 fyn kinases, and protein kinase C (PKC...

We consider the eigenvalues and eigenvectors of finite, low rank perturbations of random matrices. Specifically, we prove almost sure convergence of the extreme eigenvalues and appropriate projections of the corresponding eigenvectors of the perturbed matrix for additive and multiplicative perturbation models. The limiting non-random value is shown to depend explicitly on the limiting eigenvalu...

This paper describes a process migration facility for the Sprite operating system. In order to provide location-transparent remote execution, Sprite associates with each process a distinguished home node, which provides kernel services to the process throughout the process's lifetime. System calls that depend on the location of a process are forwarded to the process's home node. Performance mea...

This paper reports on progress towards the development of a personal guidance system for a blind navigator. The system is being developed in light of the unique problems facing the blind traveller, which are discussed first. The system consists of four modules: a locator unit, a detailed spatial database, an algorithm for path selection and a user interface. Suggestions are offered for alternat...

We present multiepoch imaging of the T5.0+T5.5 binary 2MASS J15344984 2952274AB obtained with the Keck laser guide star adaptive optics system. Combined with archival HST imaging, our total data span 50% of the orbital period. We use a Markov chain Monte Carlo analysis to determine a period of 15:1þ2:3 1:6 yr and a total mass of 0:056 0:003 M (59 3 MJ). This is the first field binary for which ...

A physician friend of mine recently was caring for a critically ill infant who was dying. The infant's mother insisted that the infant be treated with maximal life support as long as possible. The physician told me that, as a physician, he had the right and the duty to refuse to provide treatment any longer because the effort was `futile'. I pressed him about how he knew he was doing the morall...

Humanity is facing nearly insurmountable challenges, risks, and crises. Resource depletion, global pollution of the entire biosphere, and climate change due to our excessive and uncontrollably growing human population may be the most difficult long-term problems that urgently need to be solved. However, the current influenza pandemic and other unforeseen but inevitable health emergencies includ...