Confinement Effects in Antiferromagnets

Phase equilibrium in confined Ising antiferromagnets was studied as a function of the coupling (v) and a magnetic field (h) at the surfaces, in the presence of an external field H. The ground state properties were calculated exactly for symmetric boundary conditions and nearest-neighbor interactions, and a full zero-temperature phase diagram in the plane v-h was obtained for films with symmetry-preserving surface orientations. The ground-state analysis was extended to the H-T plane using a cluster-variation free energy. The study of the finite-T properties (as a function of v and h) reveals the close interdependence between the surface and finite-size effects and, together with the ground-state phase diagram, provides an integral picture of the confinement in anisotropic antiferromagnets with surfaces that preserve the symmetry of the order parameter.Comment: 10 pages, 8 figures, Accepted in Phys. Rev.

Risk factors for mortality caused by pseudomonas aeruginosa infection in hospitalized patients with oncologic diagnosis in three cities of Colombia

Pseudomonas aeruginosa es una bacteria oportunista Gram negativa particularmente eficiente en la adquisición de mecanismos de resistencia y de alta prevalencia en infecciones nosocomiales en pacientes oncológicos. Objetivo: identificar los factores de riesgo para mortalidad en pacientes oncológicos con aislamiento de P. aeruginosa. Metodología: estudio descriptivo, la población de estudio fueron los casos reportados con aislamiento de P. aeruginosa en el servicio de hospitalización de Oncólogos de Occidente en Pereira, Armenia y Manizales durante el año 2015. Se realizaron análisis univariados y multivariados; la supervivencia se estableció según el método de Kaplan-Meier. Se estableció un valor de p <0.05. Se usó el software STATA. Se tuvo aval de bioética de la Universidad Tecnológica de Pereira. Resultados: se estudió 41 casos confirmados de cultivos positivos de P. aeruginosa. El sexo masculino (46.3%), anemia (46.3%), neutropenia febril (41%), trombocitopenia (29.3%) y haber sido hospitalizado en la unidad de cuidados intensivos (29.3%) fueron asociados estadísticamente con mayor mortalidad (p=0.019); con estos resultados se diseñó una escala de riesgo (alfa de Cronbach =0.72). Los pacientes con cuatro de estas exposiciones mostraron mayor riesgo de mortalidad al egreso hospitalario con una sensibilidad del 68% y especificidad del 90%. La P. aeruginosa presentó resistencia a cefepime (36.6%) y a aztreonam (34.1%), mientras que la letalidad global fue del 26.8%. Conclusión: El sexo masculino, la coexistencia de anemia, trombocitopenia, y neutropenia febril, así como la estancia en la unidad de cuidados intensivos aumentan la mortalidad en los pacientes oncológicos infectados con P. aeruginosa.Pseudomonas aeruginosa is a Gram-negative and rod-shape opportunistic bacterium that is particularly efficient in the acquisition of resistance mechanisms and its high prevalence in nosocomial infections in cancer patients. Objective: To identify risk factors for mortality in cancer patients with P. aeruginosa infection. Methodology: A descriptive study was carried out in patients with P. aeruginosa infection during the hospitalization service of “Oncólogos de Occidente” in Pereira, Armenia and Manizales during 2015. Univariate and multivariate analyzes were performed. The survival analysis was established according to the Kaplan-Meier method. A value of p<0.05 was established for it. The analyses were examined with the STATA software. This study was endorsed by the bioethics committee of the “Universidad Tecnológica de Pereira”. Results: Fourty-one patients with positive culture for P. aeruginosa were studied. Males (46.3%), anemia (46.3%), febrile neutropenia (41%), thrombocytopenia (29.3%) and previous hospitalization in an intensive care unit (29.3%) were associated with higher mortality risk (p = 0.019); a risk scale was designed with these factors (Cronbach´s alpha = 0.72). Patients who presented four of these exposures were at higher risk of mortality with a sensitivity of 68% and specificity of 90% at the moment of discharge. P. aeruginosa showed 36.6% of resistance to cefepime, 34.1% to aztreonam, the mortality rate was 26.8%. Conclusion: Male sex, anemia, thrombocytopenia, febrile neutropenia and previous hospitalization in an intensive care unit increase the mortality rate in patients with cancer who were infected by P. aeruginosa.

Polyfunctional T cell responses in children in early stages of chronic Trypanosoma cruzi infection contrast with monofunctional responses of long-term infected adults

Background: Adults with chronic Trypanosoma cruzi exhibit a poorly functional T cell compartment, characterized by monofunctional (IFN-γ-only secreting) parasite-specific T cells and increased levels of terminally differentiated T cells. It is possible that persistent infection and/or sustained exposure to parasites antigens may lead to a progressive loss of function of the immune T cells. Methodology/Principal Findings: To test this hypothesis, the quality and magnitude of T. cruzi-specific T cell responses were evaluated in T. cruzi-infected children and compared with long-term T. cruzi-infected adults with no evidence of heart failure. The phenotype of CD4+ T cells was also assessed in T. cruzi-infected children and uninfected controls. Simultaneous secretion of IFN-γ and IL-2 measured by ELISPOT assays in response to T. cruzi antigens was prevalent among T. cruzi-infected children. Flow cytometric analysis of co-expression profiles of CD4+ T cells with the ability to produce IFN-γ, TNF-α, or to express the co-stimulatory molecule CD154 in response to T. cruzi showed polyfunctional T cell responses in most T. cruzi-infected children. Monofunctional T cell responses and an absence of CD4+TNF-α+-secreting T cells were observed in T. cruzi-infected adults. A relatively high degree of activation and differentiation of CD4+ T cells was evident in T. cruzi-infected children. Conclusions/Significance: Our observations are compatible with our initial hypothesis that persistent T. cruzi infection promotes eventual exhaustion of immune system, which might contribute to disease progression in long-term infected subjects.Fil: Albareda, María Cecilia. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud. Instituto Nacional de Parasitología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Provincia de Buenos Aires. Ministerio de Salud. Hospital Interzonal de Agudos "Eva Perón"; ArgentinaFil: de Rissio, Ana María. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud. Instituto Nacional de Parasitología; ArgentinaFil: Tomas, Gonzalo. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud. Instituto Nacional de Parasitología; ArgentinaFil: Serjan, Alicia. Gobierno de la Ciudad de Buenos Aires. Hospital General de Agudos "Juan A. Fernández"; ArgentinaFil: Alvarez, María Gabriela. Provincia de Buenos Aires. Ministerio de Salud. Hospital Interzonal de Agudos "Eva Perón"; ArgentinaFil: Viotti, Rodolfo Jorge. Provincia de Buenos Aires. Ministerio de Salud. Hospital Interzonal de Agudos "Eva Perón"; ArgentinaFil: Fichera, Laura Edith. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud. Instituto Nacional de Parasitología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Esteva, Mónica Inés. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud. Instituto Nacional de Parasitología; ArgentinaFil: Potente, Daniel Fernando. Provincia de Buenos Aires. Ministerio de Salud. Hospital Interzonal de Agudos "Eva Perón"; ArgentinaFil: Armenti, Alejandro. Provincia de Buenos Aires. Ministerio de Salud. Hospital Interzonal de Agudos "Eva Perón"; ArgentinaFil: Tarleton, Rick L.. University of Georgia; Estados UnidosFil: Laucella, Susana Adriana. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud. Instituto Nacional de Parasitología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Factores de riesgo para mortalidad en la infección por Pseudomonas aeruginosa en pacientes oncológicos hospitalizados en tres ciudades de Colombia

Introduction: Pseudomonas aeruginosa is a Gram-negative and rod-shape opportunistic bacterium that is particularly efficient in the acquisition of resistance mechanisms and its high prevalence in nosocomial infections in cancer patients. Objective: To identify risk factors for mortality in cancer patients with P. aeruginosa infection. Methodology: A descriptive study was carried out in patients with P. aeruginosa infection during the hospitalization service of “Oncólogos de Occidente” in Pereira, Armenia and Manizales during 2015. Univariate and multivariate analyzes were performed. The survival analysis was established according to the Kaplan-Meier method. A value of p<0.05 was established for it. The analyses were examined with the STATA software. This study was endorsed by the bioethics committee of the “Universidad Tecnológica de Pereira”. Results: Fourty-one patients with positive culture for P. aeruginosa were studied. Males (46.3%), anemia (46.3%), febrile neutropenia (41%), thrombocytopenia (29.3%) and previous hospitalization in an intensive care unit (29.3%) were associated with higher mortality risk (p = 0.019); a risk scale was designed with these factors (Cronbach´s alpha = 0.72). Patients who presented four of these exposures were at higher risk of mortality with a sensitivity of 68% and specificity of 90% at the moment of discharge. P. aeruginosa showed 36.6% of resistance to cefepime, 34.1% to aztreonam, the mortality rate was 26.8%. Conclusion: Male sex, anemia, thrombocytopenia, febrile neutropenia and previous hospitalization in an intensive care unit increase the mortality rate in patients with cancer who were infected by P. aeruginosa. Introducción: Pseudomonas aeruginosa es una bacteria oportunista Gram negativa particularmente eficiente en la adquisición de mecanismos de resistencia y de alta prevalencia en infecciones nosocomiales en pacientes oncológicos. Objetivo: identificar los factores de riesgo para mortalidad en pacientes oncológicos con aislamiento de P. aeruginosa. Metodología: estudio descriptivo, la población de estudio fueron los casos reportados con aislamiento de P. aeruginosa en el servicio de hospitalización de Oncólogos de Occidente en Pereira, Armenia y Manizales durante el año 2015. Se realizaron análisis univariados y multivariados; la supervivencia se estableció según el método de Kaplan-Meier. Se estableció un valor de p <0.05. Se usó el software STATA. Se tuvo aval de bioética de la Universidad Tecnológica de Pereira. Resultados: se estudió 41 casos confirmados de cultivos positivos de P. aeruginosa. El sexo masculino (46.3%), anemia (46.3%), neutropenia febril (41%), trombocitopenia (29.3%) y haber sido hospitalizado en la unidad de cuidados intensivos (29.3%) fueron asociados estadísticamente con mayor mortalidad (p=0.019); con estos resultados se diseñó una escala de riesgo (alfa de Cronbach =0.72). Los pacientes con cuatro de estas exposiciones mostraron mayor riesgo de mortalidad al egreso hospitalario con una sensibilidad del 68% y especificidad del 90%. La P. aeruginosa presentó resistencia a cefepime (36.6%) y a aztreonam (34.1%), mientras que la letalidad global fue del 26.8%. Conclusión: El sexo masculino, la coexistencia de anemia, trombocitopenia, y neutropenia febril, así como la estancia en la unidad de cuidados intensivos aumentan la mortalidad en los pacientes oncológicos infectados con P. aeruginosa

Search for squarks and gluinos in events with isolated leptons, jets and missing transverse momentum at s√=8 TeV with the ATLAS detector

The results of a search for supersymmetry in final states containing at least one isolated lepton (electron or muon), jets and large missing transverse momentum with the ATLAS detector at the Large Hadron Collider are reported. The search is based on proton-proton collision data at a centre-of-mass energy s√=8 TeV collected in 2012, corresponding to an integrated luminosity of 20 fb−1. No significant excess above the Standard Model expectation is observed. Limits are set on supersymmetric particle masses for various supersymmetric models. Depending on the model, the search excludes gluino masses up to 1.32 TeV and squark masses up to 840 GeV. Limits are also set on the parameters of a minimal universal extra dimension model, excluding a compactification radius of 1/R c = 950 GeV for a cut-off scale times radius (ΛR c) of approximately 30

Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum