3,954 research outputs found

    Do the Unidentified EGRET Sources Trace Annihilating Dark Matter in the Local Group?

    Full text link
    In a cold dark matter (CDM) framework of structure formation, the dark matter haloes around galaxies assemble through successive mergers with smaller haloes. This merging process is not completely efficient, and hundreds of surviving halo cores, or {\it subhaloes}, are expected to remain in orbit within the halo of a galaxy like the Milky Way. While the dozen visible satellites of the Milky Way may trace some of these subhaloes, the majority are currently undetected. A large number of high-velocity clouds (HVCs) of neutral hydrogen {\it are} observed around the Milky Way, and it is plausible that some of the HVCs may trace subhaloes undetected in the optical. Confirming the existence of concentrations of dark matter associated with even a few of the HVCs would represent a dramatic step forward in our attempts to understand the nature of dark matter. Supersymmetric (SUSY) extensions of the Standard Model of particle physics currently suggest neutralinos as a natural well-motivated candidate for the non-baryonic dark matter of the universe. If this is indeed the case, then it may be possible to detect dark matter indirectly as it annihilates into neutrinos, photons or positrons. In particular, the centres of subhaloes might show up as point sources in gamma-ray observations. In this work we consider the possibility that some of the unidentified EGRET Îł\gamma-ray sources trace annihilating neutralino dark matter in the dark substructure of the Local Group. We compare the observed positions and fluxes of both the unidentified EGRET sources and the HVCs with the positions and fluxes predicted by a model of halo substructure, to determine to what extent any of these three populations could be associated.Comment: 12 Pages, 4 figures, to appear in a special issue of ApSS. Presented at "The Multiwavelength Approach to Unidentified Gamma-Ray Sources" (Hong Kong, June 1 - 4, 2004; Conference organizers: K.S. Cheng and G.E. Romero

    GestiĂłn financiera y competitividad en Establecimientos de Hospedaje en la RegiĂłn JunĂ­n

    Get PDF
    The objective of determine the statistical conclusion between financial management and competitiveness in lodging establishments in the Junín region. The methodology used was a quantitative approach, basic type, correlational level and non-experimental design. To determine the population and sample, the non-probabilistic documentation was applied for convenience in order to be able to access it more easily. Questionnaires with polytomous answers and processing of these in Excel and SPSS were applied. As a result, a medium-low positive confirmation of 0.212, but statistically significant between the two variables, in terms of the dimensions of financial management and the competitiveness variable, relationships were obtained between low and high and equally statistically significant, thus verifying what was proposed in the research. Finally, it can be concluded that applying a certain use of financial management such as financial statements, use of accounting records, among others, affects competitiveness since this variable is carried out based on the human factor and the company's own resources, which generate the activities for your organization. According to the results obtained, among the most significant we have financial analysis and control, obtaining 70% and 76.7% of good management.El objetivo fue determinar la correlación estadística entre gestión financiera y competitividad en establecimientos de hospedaje en la región Junín. La metodología utilizada fue de enfoque cuantitativo, tipo básico, nivel correlacional y diseño no experimental. Para determinar la población y muestra se aplicó el muestreo no probabilístico por conveniencia con el fin de poder acceder con mayor facilidad a esta. Se aplicó cuestionarios con respuestas politómicas y procesamiento de estas en Excel y SPSS. Como resultado se determinó una fuerza de correlación estadística positiva media-baja de 0,212, pero estadísticamente significativas, con p-valor menor a 0,005 entre ambas variables, en cuanto a las dimensiones de gestión financiera y la variable competitividad se obtuvo relaciones entre bajas y altas, pero igualmente estadísticamente significativas comprobando de esta manera lo propuesto en la investigación. Por ende, se puede concluir que aplicar determinado uso de gestión financiera como estados financieros, uso de registros contables, entre otros, incide en la competitividad ya que esta variable se realiza en base al factor humano y recursos propios de la empresa las cuales generan las actividades favor de su organización. De acuerdo con los resultados obtenidos, entre los más significativos tenemos al análisis y control financiero obteniendo un 70 % y 76.7 % de buena gestión

    P-cadherin expression in breast cancer: a review

    Get PDF
    P-cadherin is frequently over-expressed in high-grade invasive breast carcinomas and has been reported to be an enhancer of migration and invasion of breast cancer cells, being correlated with tumour aggressiveness. In addition, expression of P-cadherin is well established as an indicator of poor prognosis in human breast cancer, which has stimulated our interest in studying its role in this setting. This review describes the most important findings on P-cadherin expression and function in normal mammary tissue and breast cancer cells, emphasizing that further research is required to elucidate the role played by this protein in human mammary tumours

    Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC

    Get PDF
    The uncertainty on the calorimeter energy response to jets of particles is derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the calorimeter response to single isolated charged hadrons is measured and compared to the Monte Carlo simulation using proton-proton collisions at centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009 and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter response to specific types of particles (positively and negatively charged pions, protons, and anti-protons) is measured and compared to the Monte Carlo predictions. Finally, the jet energy scale uncertainty is determined by propagating the response uncertainty for single charged and neutral particles to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3% for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table, submitted to European Physical Journal
    • …
    corecore