The Qweak Experiment: A measurement of the proton’s weak charge at Jefferson Lab

The Qweak Experiment at Jefferson Laboratory will make a 4% measurement of the proton’s weak charge, QpW, by measuring the parity-violating asymmetry in elastic electron-proton scattering at low momentum transfer, Q2 = 0.026 GeV2. This asymmetry is proportional to the weak charge of the proton and can be related to the weak mixing angle, sin2 θW, a parameter in the Standard Model. Qweak will measure the weak mixing angle precisely to 0.3%, challenging predictions of the Standard Model and probing certain types of new physics at the 2TeV scale

A MARKOV CHAIN ANALYSIS OF STRUCTURAL CHANGES IN THE TEXAS HIGH PLAINS COTTON GINNING INDUSTRY

Markov chain analysis of changes in the number and size of cotton gin firms in West Texas was conducted assuming stationary and non-stationary transition probabilities. Projections of industry structure were made to 1999 with stationary probability assumptions and six sets of assumed conditions for labor and energy costs and technological change in the non-stationary transition model. Results indicate a continued decline in number of firms, but labor, energy, and technology conditions alter the configuration of the structural changes.Crop Production/Industries,

Effect of soil moisture stress on uptake and recovery of tagged nitrogen by wheat

Includes bibliographical references (pages 42-43).Labelled 15NH4NO3 was used in a growth chamber to study the effect of moisture stress on the utilization of nitrogen by wheat. This made it possible to determine the recovery of nitrogen (N) in the soil-plant system of two Chernozemic soils. Moisture stress effects were less evident in a clay soil than in a loam. Approximately 55% of the N utilized by the growing plants came from organic soil-N mineralized during the growing period. From 59 to 71% of the initial fertilizer plus soil mineral-N was utilized by the plants. Twenty to 36% remained in the soil, and 1 to 17% was lost. Losses were greatest in soils exposed to high moisture stress and were related to the residual NO3-N levels in the soil. They were attributed to denitrification. Immobilization of N was highest at low moisture stress where plant growth was the greatest, but mineralization was unaffected by the moisture stress applied. It was estimated that 5.0 to 6.2 kg N were required to produce 100 kg of wheat, the highest efficiency of N utilization being obtained at low soil moisture stress

Determination of the Joint Confidence Region of Optimal Operating Conditions in Robust Design by Bootstrap Technique

Robust design has been widely recognized as a leading method in reducing variability and improving quality. Most of the engineering statistics literature mainly focuses on finding "point estimates" of the optimum operating conditions for robust design. Various procedures for calculating point estimates of the optimum operating conditions are considered. Although this point estimation procedure is important for continuous quality improvement, the immediate question is "how accurate are these optimum operating conditions?" The answer for this is to consider interval estimation for a single variable or joint confidence regions for multiple variables. In this paper, with the help of the bootstrap technique, we develop procedures for obtaining joint "confidence regions" for the optimum operating conditions. Two different procedures using Bonferroni and multivariate normal approximation are introduced. The proposed methods are illustrated and substantiated using a numerical example.Comment: Two tables, Three figure

The replacement histone H2A.Z in a hyperacetylated form is a feature of active genes in the chicken

The replacement histone H2A.Z is variously reported as being linked to gene expression and preventing the spread of heterochromatin in yeast, or concentrated at heterochromatin in mammals. To resolve this apparent dichotomy, affinity-purified antibodies against the N-terminal region of H2A.Z, in both a triacetylatedandnon- acetylatedstate, areusedin native chromatin immmuno-precipitation experiments with mononucleosomes from three chicken cell types. The hyperacetylated species concentrates at the 50 end of active genes, both tissue specific and housekeeping but is absent from inactive genes, while the unacetylated form is absent from both active and inactive genes. A concentration of H2A.Z is also found at insulators under circumstances implying a link to barrier activity but not to enhancer blocking. Although acetylated H2A.Z is widespread throughout the interphase genome, at mitosis its acetylation is erased, the unmodified form remaining. Thus, although H2A.Z may operate as an epigenetic marker for active genes, its N-terminal acetylation does not

Superlinear Increase of Photocurrent due to Stimulated Scattering into a Polariton Condensate

We show that when a monopolar current is passed through an n-i-n structure, superlinear photocurrent response occurs when there is a polariton condensate. This is in sharp contrast to the previously observed behavior for a standard semiconductor laser. Theoretical modeling shows that this is due to a stimulated exciton-exciton scattering process in which one exciton relaxes into the condensate, while another one dissociates into an electron-hole pair.Comment: 17 pages with 10 figure

The replacement histone H2A.Z in a hyperacetylated form is a feature of active genes in the chicken

The replacement histone H2A.Z is variously reported as being linked to gene expression and preventing the spread of heterochromatin in yeast, or concentrated at heterochromatin in mammals. To resolve this apparent dichotomy, affinity-purified antibodies against the N-terminal region of H2A.Z, in both a triacetylatedandnon- acetylatedstate, areusedin native chromatin immmuno-precipitation experiments with mononucleosomes from three chicken cell types. The hyperacetylated species concentrates at the 50 end of active genes, both tissue specific and housekeeping but is absent from inactive genes, while the unacetylated form is absent from both active and inactive genes. A concentration of H2A.Z is also found at insulators under circumstances implying a link to barrier activity but not to enhancer blocking. Although acetylated H2A.Z is widespread throughout the interphase genome, at mitosis its acetylation is erased, the unmodified form remaining. Thus, although H2A.Z may operate as an epigenetic marker for active genes, its N-terminal acetylation does not

Black-hole quasinormal modes and scalar glueballs in a finite-temperature AdS/QCD model

We use the holographic AdS/QCD soft-wall model to investigate the spectrum of scalar glueballs in a finite temperature plasma. In this model, glueballs are described by a massless scalar field in an AdS_5 black hole with a dilaton soft-wall background. Using AdS/CFT prescriptions, we compute the boundary retarded Green's function. The corresponding thermal spectral function shows quasiparticle peaks at low temperatures. We also compute the quasinormal modes of the scalar field in the soft-wall black hole geometry. The temperature and momentum dependences of these modes are analyzed. The positions and widths of the peaks of the spectral function are related to the frequencies of the quasinormal modes. Our numerical results are found employing the power series method and the computation of Breit-Wigner resonances.Comment: Revision: Results unchanged. More discussions on the model and on the results. References added. 28 pages, 7 figures, 5 table