The Nucleon Sigma Term from Threshold Parameters

A new sum rule determines the nucleon sigma term by the \pi N elastic scattering threshold parameters alone. This "threshold" value of \sigma(2\mu^2) provides an independent check of existing values obtained from global dispersive analyses, and also provides a realistic error assignment. Employing a recent analysis of low energy (T_\pi < 100 MeV) \pi N data our sum rule implies \sigma(2\mu^2) = 71\pm 9 MeV.Comment: Additional explanations and references, changes in notation, small numerical changes. 11 pages, Revtex, uses epsf.sty, 1 postscript figure. Version to be published in Physics Letters

Influence of Surface Material on the BCl Density in Inductively Coupled Discharges

The relative density of BCl radicals has been measured in a modified Applied Materials DPS metal etch chamber using laser-induced fluorescence. In plasmas containing mixtures of BCl{sub 3} with Cl{sub 2}, Ar and/or N{sub 2}, the relative BCl density was measured as a function of source and bias power, pressure, flow rate, BCl{sub 3}/Cl{sub 2} ratio and argon addition. To determine the influence of surface materials on the bulk plasma properties, the relative BCl density was measured using four different substrate types; aluminum, alumina, photoresist, and photoresist-patterned aluminum. In most cases, the relative BCl density was highest above photoresist-coated wafers and lowest above blanket aluminum wafers. The BCl density increased with increasing source power and the ratio of BCl{sub 3} to Cl{sub 2}, while the addition of N{sub 2} to a BCl{sub 3}/Cl{sub 2} plasma resulted in a decrease in BCl density. The BCl density was relatively insensitive to changes in the other plasma parameters

PROP1 and CTNNB1 expression in adamantinomatous craniopharyngiomas with or without β-catenin mutations

INTRODUCTION: Activating mutations in exon 3 of the &#946;-catenin gene are involved in the pathogenesis of adamantinomatous craniopharyngiomas. Recently, the interaction between &#946;-catenin and PROP1 has been shown to be responsible for pituitary cell lineage determination. We hypothesized that dysregulated PROP1 expression could also be involved in the pathogenesis of craniopharyngiomas OBJECTIVES: To determine whether dysregulated gene expression was responsible for tumor pathogenesis in adamantinomatous craniopharyngiomas, the &#946;-catenin gene was screened for mutations, and the expression of the &#946;-catenin gene and PROP1 was evaluated. &#946;-catenin gene was amplified and sequenced from 14 samples of adamantinomatous craniopharyngiomas. PROP1 and &#946;-catenin gene expression was assessed by real-time RT-PCR from 12 samples, and &#946;-catenin immunohistochemistry was performed on 11 samples. RESULTS: Mutations in the &#946;-catenin gene were identified in 64% of the adamantinomatous craniopharyngiomas samples. Evidence of &#946;-catenin gene overexpression was found in 71% of the tumors with &#946;-catenin mutations and in 40% of the tumors without mutations, and &#946;-catenin immunohistochemistry revealed a nuclear staining pattern for each of the analyzed samples. PROP1 expression was undetectable in all of the tumor samples. CONCLUSION: We found evidence of &#946;-catenin gene overexpression in the majority of adamantinomatous craniopharyngiomas, and we also detected a nuclear &#946;-catenin staining pattern regardless of the presence of a bcatenin gene mutation. These results suggest that WNT signaling activation plays an important role in the pathogenesis of adamantinomatous craniopharyngiomas. Additionally, this study was the first to evaluate PROP1 expression in adamantinomatous craniopharyngiomas, and the absence of PROP1 expression indicates that this gene is not involved in the pathogenesis of this tumor, at least in this cohort

Cooler Intensity Limitations

This research was sponsored by the National Science Foundation Grant NSF PHY-931478

Effect of Parametric Resonances on the Bunched-beam Dilution Mechanism

This research was sponsored by the National Science Foundation Grant NSF PHY-931478

Academic freedom: in justification of a universal ideal

This paper examines the justification for, and benefits of, academic freedom to academics, students, universities and the world at large. The paper surveys the development of the concept of academic freedom within Europe, more especially the impact of the reforms at the University of Berlin instigated by Wilhelm von Humboldt. Following from this, the paper examines the reasons why the various facets of academic freedom are important and why the principle should continue to be supported

Questions of fairness and anti-doping in US cycling: The contrasting experiences of professionals and amateurs

The focus of researchers, media and policy on doping in cycling is often limited to the professional level of the sport. However, anti-doping test results since 2001 demonstrate that banned substances are also used by US cyclists at lower levels of the sport, necessitating a broader view of the patterns and motivations of substance use within the sport. In this article, we describe and explain the doping culture that has emerged in domestic US cycling among amateur and semi-professionals. Through analysis of records from sports governing bodies and journalistic reports, we assess the range of violation types and discuss the detection and punishing of riders who were not proven to have intended to cheat but became "collateral damage" in the war on doping. We argue that the phenomenon of doping is more complex than what has been shown to occur in elite sport, as it includes a wider variety of behaviours, situations and motivations. We develop fresh insights by examining cases where doping has been accidental, intrinsically motivated, non-performance enhancing or the result of prescribed medical treatments banned by anti-doping authorities. Such trends call into question the fairness of anti-doping measures, and we discuss the possibility of developing localised solutions to testing and sanctioning amateur athletes

CE22: Nonlinear Beam Dynamics Experiments at the IUCF Cooler Ring

This research was sponsored by the National Science Foundation Grant NSF PHY-931478

Limit Cycle Instability of Proton Beams Generated by Nonlinear Electron-Cooling Force

This research was sponsored by the National Science Foundation Grant NSF PHY-931478