Improved burst disk/cutter assembly

Burst disk/cutter, prewelded before assembly, eliminates external leakage into a vacuum annulus and provides a means for more accurate burst-pressure prediction. Two reverse buckling type configurations are described and test results are given

Inexpensive check valve is installed in standard AN fittings

Check valve with a cylindrical flanged tube body is used in standard AN fittings. The valve also has an easily removable spring-loaded piston

Racial Conflicts In Schools

That racially motivated conflicts occur in schools is an indisputable fact that becomes evident upon review of both academic literature and popular media. Events such as the Jena 6 incident (Maxwell & Zehr, 2007), school wide racially motivated riots (latimes.com), and court rulings (theithican.org) are distressing examples that racial barriers are real and potentially dangerous for many students in this country. However, little is written about the nature of racial conflicts, including the actual process school leaders engage in when determining how or even whether to intervene in racial conflicts, and the affect those racial conflicts have on the school climate and relevant stakeholders (e.g. directly involved students, other students, and school staff). To address this concern the current study is designed to provide insight into the decision-making process of school counselors in the intervention of racial conflicts that occur between students. The findings of this study will be pertinent and beneficial to all educational professionals as well as students. The following review provides context for understanding racial conflicts in schools, and addresses such issues as prevalence rates, causes, consequences, theories, and interventions to address such conflicts. Finally, the review concludes with a description of limitations in the research and a description of a proposed study

Speaking Out

Why can we not take action now? I asked myself this question when, as a program coordinator for the Women’s Center I decided to take part in the Vagina Monologues because I wanted to change them- monologues that are centered on the experiences of white, upper-class cis-gender women. [excerpt

A Nonlinear Threshold Model for the Dependence of Extremes of Stationary Sequences

One of the main implications of the effcient market hypothesis (EMH) is that expected future returns on financial assets are not predictable if investors are risk neutral. In this paper we argue that financial time series offer more information than that this hypothesis seems to supply. In particular we postulate that runs of very large returns can be predictable for small time periods. In order to prove this we propose a TAR(3,1)-GARCH(1,1) model that is able to describe two different types of extreme events: a first type generated by large uncertainty regimes where runs of extremes are not predictable and a second type where extremes come from isolated dread/joy events. This model is new in the literature in nonlinear processes. Its novelty resides on two features of the model that make it different from previous TAR methodologies. The regimes are motivated by the occurrence of extreme values and the threshold variable is defined by the shock affecting the process in the preceding period. In this way this model is able to uncover dependence and clustering of extremes in high as well as in low volatility periods. This model is tested with data from General Motors stock prices corresponding to two crises that had a substantial impact in financial markets worldwide; the Black Monday of October 1987 and September 11th, 2001. By analyzing the periods around these crises we find evidence of statistical significance of our model and thereby of predictability of extremes for September 11th but not for Black Monday. These findings support the hypotheses of a big negative event producing runs of negative returns in the first case, and of the burst of a worldwide stock market bubble in the second example

Gravitational collapse: A case for thermal relaxation

Two relativistic models for collapsing spheres at different stages of evolution, which include pre-relaxation processes, are presented. The influence of relaxation time on the outcome of evolution in both cases is exhibited and established. It is shown that relaxation processes can drastically change the final state of the collapsing system. In particular, there are cases in which the value of the relaxation time determines the bounce or the collapse of the sphere.Comment: 33 pages, LaTex 2.09, 11 Postscript figures. To be published in General Relativity and Gravitatio