2,306 research outputs found

    The CMS Pixel Detector

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    The Compact Muon Solenoid Experiment (CMS) will start taking data at the Large Hadron Collider (LHC) in 2007 with the largest silicon tracking detector ever built. As a key component of this tracker, the collaboration is building a silicon pixel detector consisting of two forward/backward disks on each side of the interaction region and three barrel layers. The pixel detector will be crucial to pattern recognition and track reconstruction in the hadronic collisions of CMS and will play a key role in the physics program of the LHC. During the 2007 pilot physics run of the LHC, CMS will run with a subset of the final detector to be installed in 2008. The construction, testing and qualification of the pixel detector is an important aspect of the project and will be described in a separate contribution. In this report, the final design and results from test beam runs and expected performance of the detector are given. The expected radiation tolerance and projected lifetime of the pixel detector will be discussed as well its impact on the physics program of CMS

    Effect of Substrate Ligand Presentation on the Motility of Human T-Lymphocytes

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    EFFECT OF SUBSTRATE LIGAND PRESENTATION ON THE MOTILITY OF HUMAN T-LYMPHOCYTES George Aaron Dominguez Daniel A. Hammer T lymphocyte homing and migration is critical for host defense and immunity. T lymphocytes must be captured from blood flow, tether and roll on the endothelial surface, engage chemokine receptors, and firmly adhere and migrate to sites of inflammation or to secondary lymphoid organs. How adhesive ligands, soluble factors such as chemokines, and fluid shear flow influence the motility of T lymphocytes is important for understanding this dynamic cascade of events. In this thesis, primary human T lymphocyte motility was quantified on various adhesive ligands (haptokinesis) in the presence of chemokines (chemokinesis) and in response to fluid flow. Through the use of microcontact printing onto PDMS surfaces we created surfaces that presented ligand at controlled densities either alone or in combination. The adhesive ligands ICAM-1, VCAM-1, and fibronectin were used to quantify cell migration in the absence of chemokine revealing different modes of T lymphocyte motility with ICAM-1 having an overall greater contribution. Using the homeostatic chemokines CCL19, CCL21, and CXCL12, we demonstrated that motility is biphasic and is dependent upon ICAM-1 concentration, and by presenting chemokines in combination, we can drive motility to higher levels than what was seen with each chemokine individually. Finally we demonstrated that directed migration either upstream or downstream of fluid flow is dependent upon the presence of ICAM-1, VCAM-1, or a combination of the two and the shear rate used. We have been able to show that adhesive ligands, chemokines, and shear flow all work in concert to promote robust primary human T lymphocyte adhesion and migration on microcontact printed PDMS surfaces. This research further elucidates how T lymphocytes interpret these signals for controlling homing to and motility within secondary lymphoid organs and the mechanisms of their migration

    Cinética de imbibición e isotermas de adsorción de humedad de la semilla de jamaica (Hibiscus sabdariffa L.)

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    La jamaica es un arbusto que se cultiva para comercializar el cáliz de sus flores, pero como subproducto se obtienen las semillas, que por su valor nutritivo y alto rendimiento representan un potencial económico considerable. El objetivo de este trabajo fue describir la cinética de imbibición y las isotermas de adsorción de humedad a 25, 35 y 45ºC en tres variedades cultivadas en México ("Criolla", "China" y "Sudán"). Los resultados mostraron que el proceso de imbibición describe una curva que se ajusta al modelo de Weibull, con coeficientes α de 12.99, 8.81 y 2.21 horas y β de 0.83, 1.70 y 0.72 para las variedades Criolla, China y Sudán, respectivamente. Los modelos de GAB, y de Chung-Pfost describieron adecuadamente las isotermas de adsorción. La humedad de la capa monomolecular (coeficiente a del modelo de GAB) resultó entre 3.97 y 5.71% b.s., lo cual representa una actividad de agua entre 0.1 y 0.30. Los calores isostéricos totales de adsorción obtenidos en el intervalo de humedades de equilibrio de 6 a 22% b.s., oscilaron entre 52.85 y 42.90 .90 kJmּol-1, 60.99 y 43.41 kJmּol-1 y 51.23 y 43.20 kJmּol-1para las variedades Criolla, China y Sudán, respectivamente. A humedades de equilibrio iguales o superiores a 12 % b.s., el calor isostérico fue similar a la entalpía de vaporización del agua, pero a humedades inferiores a 6% b.s., éste alcanzó los valores más elevados

    Centro de Cultura Oceánica en la bahía el Ferrol en la ciudad de Chimbote - Perú

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    En la actualidad la ciudad de Chimbote carece de infraestructura cultural enfocada con el recurso más importante que tiene, el mar. en su historia, sus habitantes han estado muy relacionados con este recurso, beneficiados ya sea por las cualidades paisajísticas o gracias a al auge de la explotación pesquera que trajo tanta abundancia económica, marcando generaciones hasta el día de hoy. El problema de este auge es que trajo la sobreexplotación de sus recursos pesqueros, contaminación de la bahía por las fábricas y el crecimiento urbano desordenado. Todo esto tiene consecuencias hoy, la ciudad posee una imagen degradada, presentándose como un lugar únicamente de paso, logrando que el visitante ignore el glorioso pasado que tuvo la ciudad como primer puerto pesquero de mundo. La imagen degradada de la ciudad afecta en demasía al usuario Chimbotano, haciendo que este carezca de aprecio por su océano y su ciudad. Esto se ve reflejado en la falta de identidad y cultura Oceánica, no reconociendo la importancia del mar en la vida del usuario chimbotano. El proyecto de tesis solucionara esta carencia de identidad cultural dándole la ciudad un proyecto arquitectónico de Centro Cultural Oceánico que genere identidad cultural con el océano como contribución para recuperar la bahía el Ferrol. Logrará la identificación con la historia de la ciudad, dará conocimientos oceánicos, técnicos, gastronómicos junto con actitudes y valores hacia el medio ambiente marino, logrando construir una ciudad con cultura sostenible, respetuosa, responsable y orgullosa de su entorno natural oceánico

    Wy Production and Limits on Anomalous WWy Couplings in pp̅ Collisions √s = 1.96 TeV

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    We measure the cross section and the difference in rapidities between photons and charged leptons for inclusive W(→ lv) + y production in ey and µy final states. Using data corresponding to an integrated luminosity of 4.2 fb-1 collected with the D0 detector at the Fermilab Tevatron Collider, the measured cross section times branching fraction for the process pp̅ → Wy + X → lvy + X and the distribution of the charge-signed photon-lepton rapidity difference are found to be in agreement with the standard model. These results provide the most stringent limits on anomalous WW[1] couplings for data from hadron colliders: -0.4 \u3c ∆ky \u3c 0.4 and -0.08 \u3c λy \u3c 0.07 at the 95% C.L

    Evidence for Simultaneous Production of J/ψ and ϒ Mesons

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    We report evidence for the simultaneous production of J/ψ and ϒ mesons in 8.1 fb−1 of data collected at √s = 1.96 TeV by the D0 experiment at the Fermilab p¯p Tevatron Collider. Events with these characteristics are expected to be produced predominantly by gluon-gluon interactions. In this analysis, we extract the effective cross section characterizing the initial parton spatial distribution, σeff = 2.2 ± 0.7(stat) ± 0.9(syst) mb

    Wy Production and Limits on Anomalous WWy Couplings in pp̅ Collisions √s = 1.96 TeV

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    We measure the cross section and the difference in rapidities between photons and charged leptons for inclusive W(→ lv) + y production in ey and µy final states. Using data corresponding to an integrated luminosity of 4.2 fb-1 collected with the D0 detector at the Fermilab Tevatron Collider, the measured cross section times branching fraction for the process pp̅ → Wy + X → lvy + X and the distribution of the charge-signed photon-lepton rapidity difference are found to be in agreement with the standard model. These results provide the most stringent limits on anomalous WW[1] couplings for data from hadron colliders: -0.4 \u3c ∆ky \u3c 0.4 and -0.08 \u3c λy \u3c 0.07 at the 95% C.L

    Deep crustal faults and the origin and long-term flank stability of Mt. Etna : first results from the CIRCEE cruise (Oct. 2013)

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    The relation between deep crustal faults and the origin of Mount Etna, the largest and most active volcano in Europe has long been suspected due to its unusual geodynamic location. Results from a new marine geophysical survey offshore Eastern Sicily reveal the detailed geometry (location, length, dip and orientation) of a two-branched 200-km long, lithospheric scale fault system, long sought for as being the cause of Mount Etna. Using high-resolution bathymetry and seismic profiling, we image a 60-km long, previously unidentified, NW trending fault with evidence of recent displacement at the seafloor, offsetting Holocene sediments. This newly identified fault connects NE of Catania, to a known 40-km long, offshore-onshore fault system dissecting the southeastern flank of Mount Etna, generally interpreted as purely gravitational collapse structures.peer-reviewe
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