Electroweak gauge boson production at hadron colliders through O(alpha_s^2)

We describe a calculation of the O(alpha_s^2) QCD corrections to the fully differential cross section for W and Z boson production in hadronic collisions. The result is fully realistic in that it includes spin correlations, finite width effects, gamma-Z interference and allows for the application of arbitrary cuts on the leptonic decay products of the W and Z. We have implemented this calculation into a numerical program. We demonstrate the use of this code by presenting phenomenological results for several future LHC analyses and recent Tevatron measurements, including the W cross section in the forward rapidity region and the central over forward cross section ratio.Comment: 11 pages, 4 figure

Diseño e implementación de un plan de mantenimiento preventivo para camiones Isuzu con motor 6hk1 y 4hk1 usando el análisis de aceite. almacenes Santa Clara S.A. Lima, Perú

El presente trabajo académico, es una síntesis del trabajo realizado en el año 2016 del mercado automotriz peruano. En el cual la venta de vehículos automotores diseñados y construidos para el transporte de mercancías de la categoría: N1, N2 y N3 (camiones estos dos últimos), ha detenido su crecimiento de manera significativa en comparación de años anteriores, por ello resulta de suma importancia brindar un sólido servicio de post-venta a los clientes retail y flotilleros, que les asegure una alta confiabilidad y una continuidad operacional de los vehículos que adquieren. El servicio post-venta tiene como principales pilares: tener una amplia red de concesionarios autorizados a nivel nacional, stock de repuestos necesarios, precios competitivos y técnicos calificados que resuelvan adecuadamente los problemas que se presenten en los camiones. Por ello se tiene que establecer acciones y estrategias innovadoras de alto impacto que permitan mejorar cuantitativa y/o cualitativamente cualquiera de estos cuatro pilares, marcando con ello el punto de quiebre sobre el resto de empresas competidoras del mismo segmento, trayendo consigo aumentar el ingreso de camiones a sus centros de servicio vía la captación de nuevos clientes y la fidelización de los que ya se tienen en cartera. En la actualidad el mantenimiento preventivo de los camiones de carga N2 y N3 de 0 a 100000 km, resulta un costo (s/. o s/./km) de inversión importante para el cliente que realiza sus servicios de mantenimiento cada 5000 Kilómetros. Así también el tiempo de parada (horas) necesarias que implica realizar estos mantenimientos juega un papel importante en la rentabilidad final del camión. En el caso de los camiones ISUZU, de los 04 tipos de motorizaciones que poseen actualmente: 4JB1, 4JJ1, 4HK1 y 6HK1, centraremos nuestro análisis de planes de mantenimiento en estos dos últimos: 4HK1 y 6HK1, dado la mayor participación en los actuales siete (07) de los ocho (08) modelos que se comercializan en el Perú: NPR, Reward 400 DT, Reward 500, Forward 800, Forward 1000, Forward 1300 y Forward 2000. Para lograr la reducción de estos costos de mantenimiento (s/. o s/./km) de 0 a 100000 km se utilizó la ciencia de la tribología a través de la aplicación del análisis del aceite, tal cual lo realizan otras marcas en el sector automotriz peruano tales como: CATERPILLAR, MERCEDEZ BENZ, SCANIA, etc. Albarracín (2006) manifiesta que la vida útil de un equipo sólo se puede lograr si este se involucra dentro de un sistema tribológico.Trabajo academic

Ariel - Volume 4 Number 2

Editors David A. Jacoby Eugenia Miller Tom Williams Associate Editors Paul Bialas Terry Burt Michael Leo Gail Tenikat Editor Emeritus and Business Manager Richard J. Bonnano Movie Editor Robert Breckenridge Staff Richard Blutstein Mary F. Buechler Steve Glinks Len Grasman Alice M. Johnson J. D. Kanofsky Tom Lehman Dave Mayer Bernie Odd

The W boson production cross section at the LHC through O(alpha_s^2)

We compute the O(alpha_s^2) QCD corrections to the fully differential cross-section pp \to W X \to l \nu X, retaining all effects from spin correlations. The knowledge of these corrections makes it possible to calculate with high precision the W boson production rate and acceptance at the LHC, subject to realistic cuts on the lepton and missing energy distributions. For certain choices of cuts we find large corrections when going from next-to-leading order (NLO) to next-to-next-to-leading order (NNLO) in perturbation theory. These corrections are significantly larger than those obtained by parton-shower event generators merged with NLO calculations. Our calculation may be used to assess and significantly reduce the QCD uncertainties in the many studies of $W$ boson production planned at the LHC.Comment: 4 pages, revte

Reactive oxygen species-linked regulation of the multidrug resistance transporter P-glycoprotein in Nox-1 overexpressing prostate tumor spheroids

AbstractExpression of the multidrug resistance (MDR) transporter P-glycoprotein (P-gp) has been demonstrated to be regulated by hypoxia-inducible factor-1α (HIF-1α) and inhibited by intracellular reactive oxygen species (ROS). Herein, P-gp and HIF-1α expression were investigated in multicellular prostate tumor spheroids overexpressing the ROS-generating enzyme Nox-1 in comparison to the mother cell line DU-145. In Nox-1-overexpressing tumor spheroids (DU-145Nox1) generation of ROS as well as expression of Nox-1 was significantly increased as compared to DU-145 tumor spheroids. ROS generation was significantly inhibited in the presence of the NADPH-oxidase antagonists diphenylen-iodonium chloride (DPI) and 4-(2-aminoethyl)benzenesulfonyl fluoride (AEBSF). Albeit growth kinetic of DU-145Nox1 tumor spheroids was decreased as compared to DU-145 spheroids, elevated expression of Ki-67 was observed indicating increased cell cycle activity. In DU-145Nox1 tumor spheroids, expression of HIF-1α as well as P-gp was significantly decreased as compared to DU-145 spheroids, which resulted in an increased retention of the anticancer agent doxorubicin. Pretreatment with the free radical scavengers vitamin E and vitamin C increased the expression of P-gp as well as HIF-1α in Nox-1-overexpressing cells, whereas no effect of free radical scavengers was observed on mdr-1 mRNA expression. In summary, the data of the present study demonstrate that the development of P-gp-mediated MDR is abolished under conditions of elevated ROS levels, suggesting that the MDR phenotype can be circumvented by modest increase of intracellular ROS generation

Release Note -- Vbfnlo-2.6.0

Vbfnlo is a flexible parton level Monte Carlo program for the simulation of vector boson fusion (VBF), double and triple vector boson (plus jet) production in hadronic collisions at next-to-leading order (NLO) in the strong coupling constant, as well as Higgs boson plus two jet production via gluon fusion at the one-loop level. This note briefly describes the main additional features and processes that have been added in the new release -- Vbfnlo Version 2.6.0. At NLO QCD diboson production (W\gamma, WZ, ZZ, Z\gamma and \gamma\gamma), same-sign W pair production via vector boson fusion and the process W\gamma\gamma j have been implemented (for which one-loop tensor integrals up to six-point functions are included). In addition, gluon induced diboson production can be studied separately at the leading order (one-loop) level. The diboson processes WW, WZ and W\gamma can be run with anomalous gauge boson couplings, and anomalous couplings between a Higgs and a pair of gauge bosons is included in WW, ZZ, Z\gamma and \gamma\gamma diboson production. The code has also been extended to include anomalous gauge boson couplings for single vector boson production via VBF, and a spin-2 model has been implemented for diboson pair production via vector boson fusion.Comment: 14 pages, 6 tables; new code available at http://www-itp.particle.uni-karlsruhe.de/vbfnlo

Influence of surface properties on the electrical conductivity of silicon nanomembranes

Because of the large surface-to-volume ratio, the conductivity of semiconductor nanostructures is very sensitive to surface chemical and structural conditions. Two surface modifications, vacuum hydrogenation (VH) and hydrofluoric acid (HF) cleaning, of silicon nanomembranes (SiNMs) that nominally have the same effect, the hydrogen termination of the surface, are compared. The sheet resistance of the SiNMs, measured by the van der Pauw method, shows that HF etching produces at least an order of magnitude larger drop in sheet resistance than that caused by VH treatment, relative to the very high sheet resistance of samples terminated with native oxide. Re-oxidation rates after these treatments also differ. X-ray photoelectron spectroscopy measurements are consistent with the electrical-conductivity results. We pinpoint the likely cause of the differences

Experimental library screening demonstrates the successful application of computational protein design to large structural ensembles

The stability, activity, and solubility of a protein sequence are determined by a delicate balance of molecular interactions in a variety of conformational states. Even so, most computational protein design methods model sequences in the context of a single native conformation. Simulations that model the native state as an ensemble have been mostly neglected due to the lack of sufficiently powerful optimization algorithms for multistate design. Here, we have applied our multistate design algorithm to study the potential utility of various forms of input structural data for design. To facilitate a more thorough analysis, we developed new methods for the design and high-throughput stability determination of combinatorial mutation libraries based on protein design calculations. The application of these methods to the core design of a small model system produced many variants with improved thermodynamic stability and showed that multistate design methods can be readily applied to large structural ensembles. We found that exhaustive screening of our designed libraries helped to clarify several sources of simulation error that would have otherwise been difficult to ascertain. Interestingly, the lack of correlation between our simulated and experimentally measured stability values shows clearly that a design procedure need not reproduce experimental data exactly to achieve success. This surprising result suggests potentially fruitful directions for the improvement of computational protein design technology

Parametrically forced sine-Gordon equation and domain walls dynamics in ferromagnets

A parametrically forced sine-Gordon equation with a fast periodic {\em mean-zero} forcing is considered. It is shown that $\pi$-kinks represent a class of solitary-wave solutions of the equation. This result is applied to quasi-one-dimensional ferromagnets with an easy plane anisotropy, in a rapidly oscillating magnetic field. In this case the $\pi$-kink solution we have introduced corresponds to the uniform ``true'' domain wall motion, since the magnetization directions on opposite sides of the wall are anti-parallel. In contrast to previous work, no additional anisotropy is required to obtain a true domain wall. Numerical simulations showed good qualitative agreement with the theory.Comment: 3 pages, 1 figure, revte