Instantons in supersymmetric Yang-Mills and D-instantons in IIB superstring theory

The one-instanton contributions to various correlation functions of supercurrents in four-dimensional N=4 supersymmetric SU(2) Yang-Mills theory are evaluated to the lowest order in perturbation theory.Expressions of the same form are obtained from the leading effects of a single D-instanton extracted from the IIB superstring effective action around the AdS5*S5 background. This is in line with the suggested AdS/Yang-Mills correspondence. The relation between Yang--Mills instantons and D-instantons is further confirmed by the explicit form of the classical D-instanton solution in the AdS5*S5 background and its associated supermultiplet of zero modes. Speculations are made concerning instanton effects in the large-N_c limit of the SU(N_c) Yang-Mills theory.Comment: 41 pages, LaTeX. Typos corrected and minor clarifications adde

Use of remotely sensed data to detect recent changes in both areal boundary and species composition of mangrove communities along the Guyana coast.

Two approaches were taken to investigate mangrove forests located along the coast of Guyana. The first involved assessing the extent of recent changes for both species composition and areal boundary, as well as identifying the major factors associated with these changes. The second approach involved evaluating satellite imagery as a means for monitoring these communities. For the first study, a Geographic Information System (GIS) was utilized to track the changes over time. It was determined that mangrove communities located between the Pomeroon and Corentyne Rivers have experienced an overall decrease by 5.57% or a loss of 24.93 km\sp2 between the periods 1960-64 and 1986-88. Forests dominated by Rhizophora mangle and by mangrove associates were reduced by 94.23% (7.35 km\sp2) and by 10.27% (35.81 km\sp2) respectively. Avicennia germinans dominated communities experienced an increase by 3.75% (2.84 km\sp2) and mixed stands of Avicennia and Rhizophora an increase by 106.05% (15.39 km\sp2). Mangrove communities located west of the Pomeroon River towards the Moruka River experienced an overall increase by 19.09% or a gain of 121.45 km\sp2. Mangrove associate and Avicennia germinans dominated forests contribute to roughly 57% and 43% of this expansion respectively. The leading cause of mangrove forest loss between the Pomeroon and Corentyne Rivers was determined to be urban/agricultural expansion. The majority of the gains has resulted from accretion in the coastal environment. The fluctuations and the gains of mangrove communities west of the Pomeroon River could not be linked to any particular agent of change. (Abstract shortened by UMI.)Dept. of Geography. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1994 .K70. Source: Masters Abstracts International, Volume: 34-02, page: 0693. Adviser: V. Chris Lakhan. Thesis (M.A.)--University of Windsor (Canada), 1995

Managing treatment-experienced pediatric and adolescent HIV patients: role of darunavir

Darunavir is currently the most recently approved HIV-1 protease inhibitor. It is approved for twice-daily dosing with ritonavir in treatment-experienced patients as young as 6 years of age and is available in numerous pill strengths. Emergence of darunavir-specific mutations is generally slow; therefore it can retain activity against viral strains that are resistant to other protease inhibitors, including tipranavir. Darunavir pharmacokinetics, clinical efficacy, resistance mutations and pharmacodynamics, and adverse effects are reviewed here. Substantial data support its use as a potent, well-tolerated option for salvage therapy in highly treatment-experienced children and adolescents

Protein sliding and hopping kinetics on DNA

Using Monte-Carlo simulations, we deconvolved the sliding and hopping kinetics of GFP-LacI proteins on elongated DNA from their experimentally observed seconds-long diffusion trajectories. Our simulations suggest the following results: (1) in each diffusion trajectory, a protein makes on average hundreds of alternating slides and hops with a mean sliding time of several tens of ms; (2) sliding dominates the root mean square displacement of fast diffusion trajectories, whereas hopping dominates slow ones; (3) flow and variations in salt concentration have limited effects on hopping kinetics, while in vivo DNA configuration is not expected to influence sliding kinetics; furthermore, (4) the rate of occurrence for hops longer than 200 nm agrees with experimental data for EcoRV proteins

Bayesian Combinatorial Auctions

We study the following simple Bayesian auction setting: m items are sold to n selfish bidders in m independent second-price auctions. Each bidder has a private valuation function that specifies his or her complex preferences over all subsets of items. Bidders only have beliefs about the valuation functions of the other bidders, in the form of probability distributions. The objective is to allocate the items to the bidders in a way that provides a good approximation to the optimal social welfare value. We show that if bidders have submodular or, more generally, fractionally subadditive (aka XOS) valuation functions, every Bayes-Nash equilibrium of the resulting game provides a 2-approximation to the optimal social welfare. Moreover, we show that in the full-information game, a pure Nash always exists and can be found in time that is polynomial in both m and n . </jats:p

Telecommunications in the IS Curriculum

A major shift away from centralized data processing to distributed system and an increasing emphasis on the use of IS technology to link individuals and entities inside and outside the orgaxiizatioit has created an imperative to integrate the study of telecoIninuiiicatioris networks into the IS curriculum. The subject of this tutorial is to exploie the appropriate dornain of telecommunications subjects to be included in the IS curriculum md to discuss various approaches to developicg arid teaching courses in telecoininunicatioiis

Normal levels of protein C and protein S tested in the acute phase of a venous thromboembolic event are not falsely elevated

<p>Abstract</p> <p>Background</p> <p>Protein C (PC) and protein S (PS) determination is part of the thrombophilia investigation in patients with idiopathic venous thromboembolism (VTE). Based on scarce evidence it is a common notion that PC and PS levels decrease during the acute phase of VTE, necessitating delay of testing and temporary transition from warfarin to low molecular weight heparin. We have previously demonstrated that an abnormal PC or PS result determined within 24 hours of VTE diagnosis and before the initiation of warfarin needs to be repeated for confirmation ≥3 months after starting treatment and ≥14 days after stopping anticoagulation therapy. In the current study, we sought to show that normal PC and PS values determined during the acute phase of VTE are not false negatives.</p> <p>Methods</p> <p>99 patients with acute idiopathic VTE who had normal PC and PS determination within the first 24 hours of presentation and who subsequently had their oral anticoagulation discontinued after six months of therapy. PC and PS determinations were repeated ≥6 months after starting treatment and ≥ 14 days after stopping warfarin. Proportions of patients who tested abnormal on the second test were calculated and 95% confidence intervals obtained using the Wilson's score method. Data from a previously published study on patients with abnormal initial tests was included for comparison.</p> <p>Results</p> <p>None of the 99 patients who had normal PC and PS initially had an abnormal result on repeated testing (0%; 95% CI 0 - 3.7%). Data from the previous study showed that, among patients who initially had abnormal results, 40% (95%CI 35.4-84.8%) were confirmed to have low PC and 63.6% (95%CI 16.8-68.7%) low PS on repeated testing. The difference between proportions was statistically significant (χ²p-value < 0.001).</p> <p>Conclusion</p> <p>Our results suggest that PC and PS can be determined during the acute phase of VTE and whereas abnormal results need to be confirmed with repeat testing at a later date, a normal result effectively rules out deficiency with only one test.</p

How to Start and Manage a BITNET LISTSERV Discussion Group: A Beginner's Guide

The following article only attempts to outline the major steps you must take in establishing a LISTSERV discussion group. It assumes that if you are in any doubt you will be able to obtain help on demand from an expert in your local computer center or from an experienced colleague. The expert may be called the "postmaster," the "LISTSERV owner," or something similar. If you are fortunate enough to find a helpful expert, cultivate him or her. The discussion lists LSTOWN-L@INDYCMS and ARACHNET@UOTTAWA are designed specifically to provide list owners with access to LISTSERV experts and experienced list owners (see Appendix A). The following also assumes that you will be in charge of the group (i.e., you will both manage or supervise the daily operations and be responsible for its success). LISTSERV groups, particularly those that are moderated, require someone who is attentive (if not devoted) to these operations and an adept editor. Note that the mechanical and the intellectual tasks required by an electronic discussion group cannot be cleanly separated; the editor/owner should be willing and able to undertake both. Keep organizational matters as simple as possible, and as loose as possible, at least until you have a sure grasp of what your group is all about. As editor/owner, you will certainly have influence, but much will be determined by the membership as a whole. In electronic communications, "vox populi vox Dei" is as good an initial motto as you can have. At the same time, total license communicates lack of attention and concern, even lack of wit. The experts, such as we have them, agree that a successful group requires an active, though not dictatorial, editorial persona