Strange Quark Contribution to the Nucleon Spin from Electroweak Elastic Scattering Data

The total contribution of strange quarks to the intrinsic spin of the nucleon can be determined from a measurement of the strange-quark contribution to the nucleon's elastic axial form factor. We have studied the strangeness contribution to the elastic vector and axial form factors of the nucleon, using all available elastic electroweak scattering data. Specifically, we combine elastic $\nu p$ and $\bar{\nu} p$ scattering cross section data from the Brookhaven E734 experiment with elastic $ep$ and quasi-elastic $ed$ and $e$-$^4$He scattering parity-violating asymmetry data from the SAMPLE, HAPPEx, G0 and PVA4 experiments. We have not only determined these form factors at individual values of momentum-transfer ($Q^2$), as has been done recently, but also have fit the $Q^2$-dependence of these form factors using simple functional forms. We present the results of these fits using existing data, along with some expectations of how our knowledge of these form factors can be improved with data from the MicroBooNE experiment planned at Fermilab.Comment: Proceedings for SPIN 2010 Conference, Juelich, Germany, September 27 - October 2, 2010; 7 pages, 2 figure

Strange Quark Contribution to the Nucleon Spin from Electroweak Elastic Scattering Data

The total contribution of strange quarks to the intrinsic spin of the nucleon can be determined from a measurement of the strange-quark contribution to the nucleon's elastic axial form factor. We have studied the strangeness contribution to the elastic vector and axial form factors of the nucleon, using elastic electroweak scattering data. Specifically, we combine elastic $\nu p$ and $\bar{\nu} p$ scattering cross section data from the Brookhaven E734 experiment with elastic $ep$ and quasi-elastic $ed$ and $e$-$^4$He scattering parity-violating asymmetry data from the SAMPLE, HAPPEx, G0 and PVA4 experiments. We have not only determined these form factors at individual values of momentum-transfer ($Q^2$), but also have fit the $Q^2$-dependence of these form factors using simple functional forms. We present the results of these fits, along with some expectations of how our knowledge of these form factors can be improved with data from Fermilab experiments.Comment: 3 pages, 1 figure, CIPANP 201

Binary Central Stars of Planetary Nebulae Discovered Through Photometric Variability. III. The Central Star of Abell 65

A growing number of close binary stars are being discovered among central stars of planetary nebulae. Recent and ongoing surveys are finding new systems and contributing to our knowledge of the evolution of close binary systems. The push to find more systems was largely based on early discoveries which suggested that 10%–15% of all central stars are close binaries. One goal of this series of papers is confirmation and classification of these systems as close binaries and determination of binary system parameters. Here we provide time-resolved multi-wavelength photometry of the central star of Abell 65 as well as further analysis of the nebula and discussion of possible binary–nebula connections. Our results for Abell 65 confirm recent work showing that it has a close, cool binary companion, though several of our model parameters disagree with the recently published values. With our longer time baseline of photometric observations from 1989 to 2009 we also provide a more precise orbital period of 1.0037577 days

Approximate roots of a valuation and the Pierce-Birkhoff Conjecture

This paper is a step in our program for proving the Piece-Birkhoff Conjecture for regular rings of any dimension (this would contain, in particular, the classical Pierce-Birkhoff conjecture which deals with polynomial rings over a real closed field). We first recall the Connectedness and the Definable Connectedness conjectures, both of which imply the Pierce - Birkhoff conjecture. Then we introduce the notion of a system of approximate roots of a valuation v on a ring A (that is, a collection Q of elements of A such that every v-ideal is generated by products of elements of Q). We use approximate roots to give explicit formulae for sets in the real spectrum of A which we strongly believe to satisfy the conclusion of the Definable Connectedness conjecture. We prove this claim in the special case of dimension 2. This proves the Pierce-Birkhoff conjecture for arbitrary regular 2-dimensional rings

Utilizing Biological Models to Determine the Recruitment of the Irish Republican Army

Sociological models (e.g., social network analysis, small-group dynamics and gang models) have historically been used to predict the behavior of terrorist groups. However, they may not be the most appropriate method for understanding the behavior of terrorist organizations because the models were not initially intended to incorporate violent behavior of its subjects. Rather, models that incorporate life and death competition between subjects, i.e., models utilized by scientists to examine the behavior of wildlife populations, may provide a more accurate analysis. This paper suggests the use of biological models to attain a more robust method for understanding the behavior of terrorist organizations as compared to traditional methods. This paper also describes how a biological population model incorporating predator-prey behavior factors can predict terrorist organizational recruitment behavior for the purpose of understanding the factors that govern the growth and decline of terrorist organizations. The Lotka-Volterra, a biolgical model that is based on a predator-prey relationship, is applied to a highly suggestive case study, that of the Irish Republican Army. This case study illuminates how a biological model can be utilized to understand the actions of a terrorist organization

Dissection of a novel molecular determinant mediating Golgi to trans -Golgi network transition

Abstract.: Two major functions of the Golgi apparatus (GA) are formation of complex glycans and sorting of proteins destined for various subcellular compartments or secretion. To fulfill these tasks proper localization of the accessory proteins within the different sub-compartments of the GA is crucial. Here we investigate structural determinants mediating transition of the two glycosyltransferases β-1,4- galactosyltransferase 1 (gal-T1) and the α-1,3-fucosyltransferase 6 (fuc-T6) from the trans-Golgi cisterna to the trans-Golgi network (TGN). Upon treatment with the ionophore monensin both glycosyltransferases are found in TGN-derived swollen vesicles, as determined by confocal fluorescence microscopy and density gradient fractionation. Both enzymes carry a signal consisting of the amino acids E5P6 in gal-T1 and D2P3 in fuc-T6 necessary for the transition of these glycosyltransferases from the trans-Golgi cisterna to the TGN, but not for their steady state localization in the trans-Golgi cistern

Estudio comparativo entre la hipótesis de la mortalidad aditiva y la hipótesis de la mortalidad compensatoria mediante el empleo de un modelo de efectos aleatorios basado en datos de recuperación de anillas

The interaction of an additional source of mortality with the underlying "natural" one strongly affects population dynamics. We propose an alternative way to test between two forms of interaction, total additivity and compensation. In contrast to existing approaches, only ring–recovery data where the cause of death of each recovered individual is known are needed. Cause–specific mortality proportions are estimated based on a multistate capture–recapture model. The hypotheses are tested by inspecting the correlation between the cause–specific mortality proportions. A variance decomposition is performed to obtain a proper estimate of the true process correlation. The estimation of the cause–specific mortality proportions is the most critical part of the approach. It works well if at least one of the two mortality rates varies across time and the two recovery rates are constant across time. We illustrate this methodology by a case study of White Storks Ciconia ciconia where we tested whether mortality induced by power line collision is additive to other forms of mortality.La interacción de una fuente adicional de mortalidad con la fuente subyacente "natural" incide de forma considerable en la dinámica poblacional. Proponemos un método alternativo para comprobar los dos tipos de interacción: la aditividad total y la compensación. A diferencia de lo que sucede con los modelos empleados actualmente, en este caso sólo se precisan datos de recuperación de anillas de cada uno de los individuos recuperados cuando se conoce la causa que ha provocado su muerte. Los porcentajes de mortalidad inducida por una causa específica se estiman a partir de un modelo de captura–recaptura multiestado. Las hipótesis se comprueban examinando la correlación existente entre los porcentajes de mortalidad inducida por una causa específica. Posteriormente, se efectúa una descomposición de varianza a fin de obtener una estimación apropiada de la verdadera correlación del proceso. La estimación de los porcentajes de mortalidad provocada por una causa específica representa el punto más crítico de este planteamiento. Funciona adecuadamente si por lo menos una de las dos tasas de mortalidad varía con el tiempo y las dos tasas de recuperación se mantienen constantes en el tiempo. Para ilustrar esta metodología, presentamos un estudio de la cigüeña blanca Ciconia ciconia, en el que verificamos si la mortalidad inducida por colisiones con los tendidos eléctricos se suma a otras formas de mortalidad

Hat hier jemand gesagt, der Kaiser sei nackt? Eine Verteidigung der Geussschen Kritik an Rawls? idealtheoretischem Ansatz [?Did Somebody Just Say the Emperor is Naked? In Defence of Geuss's Objections to Rawls's Ideal-Theoretical Approach?]

In this paper, we take up two objections Raymond Geuss levels against John Rawls? ideal theory in Philosophy and Real Politics. We show that, despite their fundamental disagreements, the two theorists share a common starting point: they both (a) reject doing political philosophy by way of applying an independently derived moral theory; and (b) grapple with the danger of unduly privileging the status quo. However, neither Rawls? characterization of politics nor his ideal theoretical approach as response to the aforementioned danger is adequate or so we argue. Moreover, contrary to received opinion, Geuss? political philosophy is the more reflective and the more philosophical of the two. In a final section, we highlight another agreement: both think that political philosophers should develop conceptual innovations as a way of clarifying and overcoming practical problems. We demonstrate that Geuss could offer a number of reasons for finding Rawls? conceptual innovations wanting