1,208 research outputs found

    Measurement of the Transverse Single Spin Asymmetry of pp + p↑p^\uparrow →\rightarrow η\eta + XX at s\sqrt{s} = 200 GeV

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    The measurement of transverse single spin asymmetries (ANA_N) provides insight into the structure of the nucleon. Several mechanisms have been proposed that attempt to explain ANA_N based on QCD, and additional measurements of ANA_N for different processes further constrain these models. Using the PHENIX detector at the Relativistic Heavy Ion Collider (RHIC), we study transversely polarized p+p collisions. Results from PHENIX and other experiments show significant asymmetries in the forward region, which could be due to contributions from both the Sivers and the Collins effects. Studying the species as well as the kinematic dependencies of these transverse single spin asymmetries will help to disentangle the origin of the observed asymmetries. Therefore, measurements of ANA_N with inclusive η\eta mesons at forward rapidities are an important tool for the understanding of these asymmetries. In 2008, the PHENIX experiment collected 5.2 pb−1^{-1} integrated luminosity in p↑+pp^\uparrow+p collisions at s\sqrt{s} = 200 GeV. The status of the asymmetry analysis of η\eta mesons at forward rapidity will be shown.Comment: 4 pages, 3 figure

    Study of congenital Morgagnian cataracts in Holstein calves

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    Cataracts are focal to diffuse opacities of the eye lens causing impaired vision or complete blindness. For bilateral congenital cataracts in Red Holsteins a perfectly cosegregating mutation within the CPAMD8 gene (CPAMD8:g.5995966C>T) has been reported. We genotyped the CPAMD8:g.5995966C>T variant in Holstein calves affected by congenital bilateral congenital cataracts, their unaffected relatives and randomly selected herd mates. Ophthalmological examinations were performed in all affected individuals to confirm a congenital cataract. Whole genome sequencing was employed to screen variants in candidate genes for the Morgagnian cataract phenotype. In the present study, 3/35 cases were confirmed as homozygous mutated and 6/14 obligate carriers. Further 7/46 unaffected animals related with these cases were heterozygous mutated for the CPAMD8:g.5995966C>T variant. However 32 cases with a congenital cataract showed the wild type for the CPAMD8 variant. We did not identify variants in the candidate genes CPAMD8 and NID1 or in their close neighborhood as strongly associated with the congenital cataract phenotype in Holstein calves with the CPAMD8 wild type. In conclusion, the CPAMD8:g.5995966C>T variant is insufficient to explain the majority of Morgagnian congenital cataract phenotypes in Holsteins. It is very likely that congenital bilateral cataracts may be genetically heterogeneous and not yet known variants in genes other than CPAMD8 and NID1 are involved

    New developments in the statistical approach of parton distributions

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    We recall how parton distributions are constructed in a statistical physical picture of the nucleon. The chiral properties of QCD lead to strong relations between quarks and antiquarks distributions and the importance of the Pauli exclusion principle is also emphasized. A global next-to-leading order QCD analysis of unpolarized and polarized deep-inelastic scattering data allows to determine a small number of free parameters. Some predictions are compared to recent experimental results and we discuss the prospects of this physical framework.Comment: 10 pages, 12 figures. Invited talk presented at the " Corfu Summer Institute on EPP,CORFU2005, Corfu, Greece, September 4-26, 2005. To be published in Journal of Physics, Conference Series (2006

    Depth-to-water maps as predictors of rut severity in fully mechanized harvesting operations

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    The preservation of the functionality of forest soil is a key aspect in planning mechanized harvesting operations. Therefore, knowledge and information about stand and soil characteristics are vital to the planning process. In this respect, depth-to-water (DTW) maps were reviewed with regard to their potential use as a prediction tool for wheel ruts. To test the applicability of open source DTW maps for prediction of rutting, the ground surface conditions of 20 clear-cut sites were recorded post harvesting, using an unmanned aerial vehicle (UAV). In total, 80 km of machine tracks were categorized by the severity of occurring rut-formations to investigate whether: i) operators intuitively avoid areas with low DTW values, ii) a correlation exists between decreasing DTW values and increasing rut severity, and iii) DTW maps can serve as reliable decision-making tool in minimizing the environmental effects of big machinery deployment. While the machine operators did not have access to these predictions (DTW maps) during the operations, there was no visual evidence that driving through these areas was actively avoided, resulting in a higher density of severe rutting within areas with DTW values <1 m. A logistic regression analysis confirmed that the probability of severe rutting rapidly increases with decreasing DTW values. However, significant differences between sites exist which might be attributed to a series of other factors such as soil type, weather conditions, number of passes and load capacity. Monitoring these factors is hence highly recommended in any further follow-up studies on soil trafficability.publishedVersio

    Generation of scenarios from calibrated ensemble forecasts with a dual ensemble copula coupling approach

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    Probabilistic forecasts in the form of ensemble of scenarios are required for complex decision making processes. Ensemble forecasting systems provide such products but the spatio-temporal structures of the forecast uncertainty is lost when statistical calibration of the ensemble forecasts is applied for each lead time and location independently. Non-parametric approaches allow the reconstruction of spatio-temporal joint probability distributions at a low computational cost. For example, the ensemble copula coupling (ECC) method rebuilds the multivariate aspect of the forecast from the original ensemble forecasts. Based on the assumption of error stationarity, parametric methods aim to fully describe the forecast dependence structures. In this study, the concept of ECC is combined with past data statistics in order to account for the autocorrelation of the forecast error. The new approach, called d-ECC, is applied to wind forecasts from the high resolution ensemble system COSMO-DE-EPS run operationally at the German weather service. Scenarios generated by ECC and d-ECC are compared and assessed in the form of time series by means of multivariate verification tools and in a product oriented framework. Verification results over a 3 month period show that the innovative method d-ECC outperforms or performs as well as ECC in all investigated aspects

    L'Expression de l'absurde chez Ionesco: du texte écrit à la représentation

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    EugĂšne Ionesco belongs to a group of dramatists known as the Theater of the Absurd, a concept coined by Martin Esslin. I argue that this concept of the absurd is inconsistent since the definition is linked to the opinions and conventions of each era. Therefore, the term absurd is imprecise when applied to theater, an art form that is directly linked to the period in which it is written and in which it is performed. I propose the idea of anti-theater, a concept mentioned by Ionesco within his work, to better define Ionesco's plays

    Extracting Nuclear Transparency from p-A Cross sections

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    We study nuclear structure effects on the transparency in high transverse momentum (p,2p)(p,2p) and (e,eâ€Čp)(e,e'p) reactions. We show that in the DWIA-eikonal approximation, even when correlations are included, one can get a factorized expression for the transparency. This depends only on the average nucleon density ρ(r)\rho(r) and a correlation function. We develop a technique to include correlations in a Monte-Carlo Glauber type calculation. We compare calculations of TT using the eikonal formalism and a continuous density, with a Monte Carlo method based on discrete nucleons.Comment: 22 pages, 9 postscript figures. LaTeX with epsf styl
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