Applications of Nonrelativistic Effective Field Theories to quarkonium systems with a small radius

We review some predictions of nonrelativistic effective field theories for heavy quark-antiquark systems with a small typical radius, r<1/\Lambda_QCD.Comment: 4 pages, uses espcrc2.sty, talk given at the BEACH2002 Conference, Vancouver, June 200

Nonlinear optical properties of a three-dimensional anisotropic quantum dot

The linear and nonlinear optical properties in a three-dimensional anisotropic quantum dot subjected to a uniform magnetic field directed with respect to the $z-$axis have been investigated within the compact-density matrix formalism and the iterative method. The dependence of the linear and nonlinear optical properties on characteristic frequency of the parabolic potential, on the magnetic field and on the incident optical intensity is detailedly studied. Moreover, take into account the position-dependent effective mass, the dependence of the linear and nonlinear optical properties on the dot radius is investigated. The results show that the optical absorption coefficients (ACs) and refractive index (RI) changes of the anisotropic quantum dot (QD) have strongly affected by these factors, and the position effect also plays an important role in the optical ACs and RI changes of the anisotropic QD.Comment: 12pages 8 figures, accpeted for publication in solid state communication

A Typical Country Doctor : Robert B. Elderdice, McKnightstown

The drive home from the Cashtown area home of the Kuhn family was cold and dark, but the twenty-one-year-old medical student was exhilarated. It was after four o\u27clock on a Monday morning, December 16, 1867. He had just assisted Mrs. Abner (Rebecca) Kuhn deliver her third child, a 14-pound son, the first of over one thousand such deliveries during his medical career. Arriving back at his lodging in the McKnightstown area, he would make the first entry in his obstetrical journal. This neat, detailed journal would eventually hold the record of 1026 cases, most involving families in the Franklin township area of Adams county, Pennsylvania. [excerpt

Optimal Distributed Covering Algorithms

We present a time-optimal deterministic distributed algorithm for approximating a minimum weight vertex cover in hypergraphs of rank f. This problem is equivalent to the Minimum Weight Set Cover problem in which the frequency of every element is bounded by f. The approximation factor of our algorithm is (f+epsilon). Let Delta denote the maximum degree in the hypergraph. Our algorithm runs in the congest model and requires O(log{Delta} / log log Delta) rounds, for constants epsilon in (0,1] and f in N^+. This is the first distributed algorithm for this problem whose running time does not depend on the vertex weights nor the number of vertices. Thus adding another member to the exclusive family of provably optimal distributed algorithms. For constant values of f and epsilon, our algorithm improves over the (f+epsilon)-approximation algorithm of [Fabian Kuhn et al., 2006] whose running time is O(log Delta + log W), where W is the ratio between the largest and smallest vertex weights in the graph. Our algorithm also achieves an f-approximation for the problem in O(f log n) rounds, improving over the classical result of [Samir Khuller et al., 1994] that achieves a running time of O(f log^2 n). Finally, for weighted vertex cover (f=2) our algorithm achieves a deterministic running time of O(log n), matching the randomized previously best result of [Koufogiannakis and Young, 2011]. We also show that integer covering-programs can be reduced to the Minimum Weight Set Cover problem in the distributed setting. This allows us to achieve an (f+epsilon)-approximate integral solution in O((1+f/log n)* ((log Delta)/(log log Delta) + (f * log M)^{1.01}* log epsilon^{-1}* (log Delta)^{0.01})) rounds, where f bounds the number of variables in a constraint, Delta bounds the number of constraints a variable appears in, and M=max {1, ceil[1/a_{min}]}, where a_{min} is the smallest normalized constraint coefficient. This improves over the results of [Fabian Kuhn et al., 2006] for the integral case, which combined with rounding achieves the same guarantees in O(epsilon^{-4}* f^4 * log f * log(M * Delta)) rounds

Coexistence of different base periodicities in prokaryotic genomes as related to DNA curvature, supercoiling, and transcription

We analyzed the periodic patterns in E. coli promoters and compared the distributions of the corresponding patterns in promoters and in the complete genome to elucidate their function. Except the three-base periodicity, coincident with that in the coding regions and growing stronger in the region downstream from the transcriptions start (TS), all other salient periodicities are peaked upstream of TS. We found that helical periodicities with the lengths about B-helix pitch ~10.2-10.5 bp and A-helix pitch ~10.8-11.1 bp coexist in the genomic sequences. We mapped the distributions of stretches with A-, B-, and Z- like DNA periodicities onto E.coli genome. All three periodicities tend to concentrate within non-coding regions when their intensity becomes stronger and prevail in the promoter sequences. The comparison with available experimental data indicates that promoters with the most pronounced periodicities may be related to the supercoiling-sensitive genes.Comment: 23 pages, 6 figures, 2 table

Quadratic Core-Selecting Payment Rules for Combinatorial Auctions

We report on the use of a quadratic programming technique in recent and upcoming spectrum auctions in Europe. Specifically, we compute a unique point in the core that minimizes the sum of squared deviations from a reference point, for example, from the Vickrey-Clarke-Groves payments. Analyzing the Karush-Kuhn-Tucker conditions, we demonstrate that the resulting payments can be decomposed into a series of economically meaningful and equitable penalties. Furthermore, we discuss the benefits of this combinatorial auction, explore the use of alternative reserve pricing approaches in this context, and indicate the results of several hundred computational runs using CATS data.Auctions, spectrum auctions, market design, package auction, clock auction, combinatorial auction

An airborne FLIR detection and warning system for low altitude wind shear

It is shown through some preliminary flight measurement research that a forward looking infrared radiometer (FLIR) system can be used to successfully detect the cool downdraft of downbursts (microbusts/macrobursts) and thunderstorm gust front outflows that are responsible for most of the low altitude wind shear (LAWS) events. The FLIR system provides a much greater safety margin for the pilot than that provided by reactive designs such as inertial air speed systems. Preliminary results indicate that an advanced airborne FLIR system could provide the pilot with remote indication of microburst (MB) hazards along the flight path ahead of the aircraft. Results of a flight test of a prototype FLIR system show that a minimum warning time of one to four minutes (5 to 10 km), depending on aircraft speed, is available to the pilot prior to the microburst encounter

Vulnerable Seniors: Unions, Tenure and Wages Following Permanent Job Loss

A well known finding in the literature on displaced workers is the apparent “portability” of tenure across firms: controlling for experience and other observable characteristics, workers with high levels of predisplacement tenure earn higher postdisplacement wages (e.g. Kletzer 1989). Using four data sets on displaced workers, we show that this finding is reversed for workers losing unionized jobs. Our finding cannot be explained by firm- or industry-specific human capital accumulation, deferred-pay policies, standard matching models, or by a correlation between tenure and re-entry rates into unionized jobs. We argue instead that it can reflect only two possible processes: negative selection of senior union workers, or a negative causal effect of unionism on workers’ alternative skills. An important implication of our findings is that, despite a much flatter predisplacement tenure-wage profile, displaced union workers’ wage losses increase with tenure at a comparable or higher rate to that of nonunion workers.