On the arithmetic of tight closure

We provide a negative answer to an old question in tight closure theory by showing that the containment x^3y^3 \in (x^4,y^4,z^4)^* in K[x,y,z]/(x^7+y^7-z^7) holds for infinitely many but not for almost all prime characteristics of the field K. This proves that tight closure exhibits a strong dependence on the arithmetic of the prime characteristic. The ideal (x,y,z) \subset K[x,y,z,u,v,w]/(x^7+y^7-z^7, ux^4+vy^4+wz^4+x^3y^3) has then the property that the cohomological dimension fluctuates arithmetically between 0 and 1

Sintered diamond compacts using metallic cobalt binders

Method is developed for sintering diamond powder which uses metallic cobalt as binder. Present samples show maximum microhardness of over 3000 kg/sq mm on Knoop scale. Material may be used as hard surface coating or may compete with cubic boron nitride as abrasive grain

Lipid peroxidation biomarkers for evaluating oxidative stress in equine neuroaxonal dystrophy.

BackgroundEquine neuroaxonal dystrophy/equine degenerative myeloencephalopathy (eNAD/EDM) is a neurodegenerative disorder affecting genetically predisposed foals maintained on an α-tocopherol (α-TOH) deficient diet. Currently no antemortem diagnostic test for eNAD/EDM is available.HypothesisBecause α-TOH deficiency is associated with increased lipid peroxidation, it was hypothesized that F2 -isoprostanes (F2 IsoP), F4 -neuroprostanes (F4 NP) and oxysterols derived from free radical oxidation would be increased in the cerebrospinal fluid (CSF) and neural tissue of eNAD/EDM affected horses and could serve as potential biomarkers for disease.AnimalsIsoprostane Study A: 14 Quarter horse foals (10 healthy foals and 4 eNAD/EDM affected foals) at 1 and 6 months of age. Isoprostane Study B: 17 eNAD/EDM affected and 10 unaffected horses ≥ 1-4 years of age. Oxysterol study: eNAD/EDM affected (n = 14, serum; n = 11, CSF; n = 10, spinal cord [SC]) and unaffected horses 1-4 years of age (n = 12, serum; n = 10, CSF; n = 7, SC).ProceduresCerebrospinal fluid [F2 IsoP] and [F4 NP] were assessed using gas chromatography-negative ion chemical ionization mass spectrometry. Serum, CSF, and cervical SC [oxysterols] were quantified using high performance liquid chromatography mass spectrometry. Results were compared with respective α-TOH concentrations.ResultsSpinal cord [7-ketocholesterol], [7-hydroxycholesterol], and [7-keto-27-hydrocholesterol] were higher in eNAD/EDM horses whereas [24-ketocholesterol] was lower. No significant difference was found in CSF [F2 IsoP] and [F4 NP], serum [oxysterols] and CSF [oxysterols] between eNAD/EDM affected and unaffected horses. No correlation was found between [F2 IsoP], [F4 NP], or [oxysterols] and respective [α-TOH].Conclusions and clinical importanceIn the SC, targeted markers of cholesterol oxidation were significantly increased in horses with eNAD/EDM

Initial experience and outcome of a new hemodialysis access device for catheter-dependent patients

ObjectiveThe effects of a new long-term subcutaneous vascular access device were studied in access-challenged patients who were poor candidates for fistulas or grafts due to venous obstruction. Bacteremia rates, patency, and function of the Hemodialysis Reliable Outflow (HeRO) Vascular Access Device (Hemosphere Inc, Minneapolis, Minn) were evaluated.MethodsThe HeRO device consists of a 6-mm expanded polytetrafluoroethylene graft attached to a 5-mm nitinol-reinforced silicone outflow component designed to bypass venous stenoses and enter the internal jugular vein directly, providing continuous arterial blood flow into the right atrium. The HeRO device was studied in a multicenter clinical trial to test the hypothesis that access-challenged patients would experience a statistically significant reduction in bacteremia rates compared with a tunneled dialysis catheter (TDC) literature control of 2.3/1000 days. HeRO-related bacteremia rates, adequacy of dialysis, patency, and adverse events were analyzed.ResultsThe HeRO device was implanted in 36 access-challenged patients who were followed for a mean 8.6 months (9931 HeRO days). The HeRO-related bacteremia rate was 0.70/1000 days. All HeRO-related bacteremias occurred during the bridging period when a TDC was still implanted before HeRO graft incorporation. HeRO adequacy of dialysis (mean Kt/V) was 1.7. HeRO primary patency was 38.9%, and secondary patency was 72.2%.ConclusionsIn access-challenged patients, a statistically significant reduction in HeRO-related bacteremia was noted compared with TDC literature. The device had similar function and patency compared with conventional arteriovenous graft literature

Relinquishing and Governing the Volatile: The Many Afghanistans and Critical Research Agendas of NATO's Governance

This article invites academics and policy analysts to examine the mechanisms and legacy of NATO's security and development governance of Afghan social spaces by using critical theory concepts. It argues that such scholarly endeavors are growing in importance as the United States and NATO gradually pull their troops out of Afghanistan. Thus, the article suggests a broad twofold research agenda. First, it points out that researching social spaces such as towns, villages, marketplaces, and neighborhoods beyond the realm of intergovernmental politics can lead to thick descriptions of how such places have been governed from within by agents external to them. Second, the study argues for a multifaceted examination of instruments, strategies, and institutions of security governance, its conduct and social effects by deploying critical and Foucauldian concepts such as the rationality and apparatuses of power relations. Thereby, it proposes an inquiry into Provincial Reconstruction Teams and Afghan National Security Forces as spatially and temporally specific apparatuses of surveillance and security

Compact relaxations for polynomial programming problems

Reduced RLT constraints are a special class of Reformulation- Linearization Technique (RLT) constraints. They apply to nonconvex (both continuous and mixed-integer) quadratic programming problems subject to systems of linear equality constraints. We present an extension to the general case of polynomial programming problems and discuss the derived convex relaxation. We then show how to perform rRLT constraint generation so as to reduce the number of inequality constraints in the relaxation, thereby making it more compact and faster to solve. We present some computational results validating our approach

Sociodemographic Factors Associated with AIDS Knowledge in a Random Sample of University Students

A telephone survey was used to assess knowledge of the transmission, prevalence, and infectivity of acquired immunodeficiency syndrome (AIDS), and the safety of casual contact among 214 randomly selected university students. Males were more knowledgeable than females overall (odds ratio [OR], men/women = 4.8). Although most students understood the dangers of unprotected sex and intravenous needle sharing, up to 30% believed some kinds of casual contact (e.g., shared eating utensils) can transmit AIDS. Older students (≥ 23 yrs) were more knowledgeable than those 17 to 19 years old about the safety of casual contact (OR = 3.8). Students are in need of education programs that stress the ways AIDS is not transmitted. Since most students identified newspapers and television as their main sources of information, these may be effective vehicles for education efforts.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73095/1/j.1525-1446.1991.tb00654.x.pd

Regularity of Edge Ideals and Their Powers

We survey recent studies on the Castelnuovo-Mumford regularity of edge ideals of graphs and their powers. Our focus is on bounds and exact values of $\text{ reg } I(G)$ and the asymptotic linear function $\text{ reg } I(G)^q$, for $q \geq 1,$ in terms of combinatorial data of the given graph $G.$Comment: 31 pages, 15 figure