12,448 research outputs found
Aggregating Litigation
A comment on Judith Resnik\u27s article on the aggregation of civil cases is presented. The goals of aggregating litigation and the very circumstances in which aggregation works best in achieving those goals are discussed. The aggregation of personal injury cases is also discussed
Fixed Number and Quantum Size Effects in Nanoscale Superconductors
In recent experiments on nanoscale Al particles, whose electron number was
fixed by charging effects, a ``negative gap'' was observed in particles with an
odd number of electrons. This observation has called into question the use of a
grand canonical ensemble in describing superconductivity in such ultrasmall
particles.
We have studied the effects of fixed electron number and finite size in
nanoscale superconductors, by applying the canonical BCS theory for the
attractive Hubbard model. The ground state energy and the energy gap are
compared with the conventional and parity-projected grand canonical BCS
results, and in one dimension also with the exact solutions by the Bethe
ansatz. The crossover from the bulk to quantum limit is studied for various
regimes of electron density and coupling strength. The effects of boundary
conditions and different lattice structures are also examined.
A ``negative gap'' for odd electron number emerges most naturally in the
canonical scheme. For even electron number, the gap is particularly large for
``magic numbers'' of electrons for a given system size or of atoms for a fixed
electron density. These features are in accordance with the exact solutions,
but are essentially missed in the grand canonical results.Comment: 2 pages, 4 figures, submitted to Physica C for M2S-HTSC-VI
Proceeding
The Drafting of the Housing Legislation
This diploma project has been focused on optimization of the D2B IR detector fabrication process using different mesa sidewall treatments and passivation methods. X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and atomic force microscope (AFM) measurements have been carried out on samples treated by different wet etching methods, to analyze their surface chemical composition and roughness. The surface roughness has been improved by critic etching, annealing and NaClO sequential treatment steps. Then these results have been utilized to improve the process of the D2B IR detectors. The dark current of the fabricated detectors passivated with various techniques have been characterized by I-V measurements at low (77 K) and room temperatures. The dark current mechanisms owing to surface shunt or bulk leakage are investigated by dark current temperature dependence analysis. By photoresist passivation devices with least leakage current are achieved
FOREIGN ECONOMIC DEVELOPMENT: THE NEED AND HOW WELL IT IS BEING MET
International Development,
Likelihood-based inference of B-cell clonal families
The human immune system depends on a highly diverse collection of
antibody-making B cells. B cell receptor sequence diversity is generated by a
random recombination process called "rearrangement" forming progenitor B cells,
then a Darwinian process of lineage diversification and selection called
"affinity maturation." The resulting receptors can be sequenced in high
throughput for research and diagnostics. Such a collection of sequences
contains a mixture of various lineages, each of which may be quite numerous, or
may consist of only a single member. As a step to understanding the process and
result of this diversification, one may wish to reconstruct lineage membership,
i.e. to cluster sampled sequences according to which came from the same
rearrangement events. We call this clustering problem "clonal family
inference." In this paper we describe and validate a likelihood-based framework
for clonal family inference based on a multi-hidden Markov Model (multi-HMM)
framework for B cell receptor sequences. We describe an agglomerative algorithm
to find a maximum likelihood clustering, two approximate algorithms with
various trade-offs of speed versus accuracy, and a third, fast algorithm for
finding specific lineages. We show that under simulation these algorithms
greatly improve upon existing clonal family inference methods, and that they
also give significantly different clusters than previous methods when applied
to two real data sets
Electronic Shell Structure of Nanoscale Superconductors
Motivated by recent experiments on Al nanoparticles, we have studied the
effects of fixed electron number and small size in nanoscale superconductors,
by applying the canonical BCS theory for the attractive Hubbard model in two
and three dimensions. A negative ``gap'' in particles with an odd number of
electrons as observed in the experiments is obtained in our canonical scheme.
For particles with an even number of electrons, the energy gap exhibits shell
structure as a function of electron density or system size in the weak-coupling
regime: the gap is particularly large for ``magic numbers'' of electrons for a
given system size or of atoms for a fixed electron density. The grand canonical
BCS method essentially misses this feature. Possible experimental methods for
observing such shell effects are discussed.Comment: 5 pages, 5 figure
- …