Effects of Bose-Einstein Condensation on forces among bodies sitting in a boson heat bath

We explore the consequences of Bose-Einstein condensation on two-scalar-exchange mediated forces among bodies that sit in a boson gas. We find that below the condensation temperature the range of the forces becomes infinite while it is finite at temperatures above condensation.Comment: 10 pages, 2 figure

Long-term results of iliac aneurysm repair with iliac branched endograft. A 5-year experience on 100 consecutive cases

Background: Iliac branch device (IBD) technique has been introduced as an appealing and effective solution to avoid complications occurring during repair of aorto-iliac aneurysm with extensive iliac involvement. Nevertheless, no large series with long-term follow-up of IBD are available. The aim of this study was to analyse safety and long-term efficacy of IBD in a consecutive series of patients.Methods: Between 2006 and 2011, 100 consecutive patients were enrolled in a prospective database on IBD. Indications included unilateral or bilateral common iliac artery aneurysms combined or not with abdominal aneurysms. Patients were routinely followed up with computed tomography. Data were reported according to the Kaplan-Meier method.Results: There were 96 males, mean age 74.1 years. Preoperative median common iliac aneurysm diameter was 40 mm (interquartile range (IQR): 35-44 mm). Sixty-seven patients had abdominal aortic aneurysm >35 mm (IQR: 40-57 mm) associated with iliac aneurysm. Eleven patients presented hypogastric aneurysm. Twelve patients underwent isolated iliac repair with IBD and 88 patients received associated endovascular aortic repair. Periprocedural technical success rate was 95%, with no mortality. Two patients experienced external iliac occlusion in the first month. At a median follow-up of 21 months (range 1-60) aneurysm growth >3 mm was detected in four iliac (4%) arteries. Iliac endoleak (one type III and two distal type I) developed in three patients and buttock claudication in four patients. Estimated patency rate of internal iliac branch was 91.4% at 1 and 5 years. Freedom from any reintervention rate was 90% at 1 year and 81.4% at 5 years. No late ruptures occurred.Conclusions: Long-term results show that IBD use can ensure persistent iliac aneurysm exclusion at 5 years, with low risk of reintervention. This technique can be considered as a first endovascular option in patients with extensive iliac aneurysm disease and favourable anatomy. (C) 2011 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved

Long range neutrino forces in the cosmic relic neutrino background

Neutrinos mediate long range forces among macroscopic bodies in vacuum. When the bodies are placed in the neutrino cosmic background, these forces are modified. Indeed, at distances long compared to the scale $T^{-1}$, the relic neutrinos completely screen off the 2-neutrino exchange force, whereas for small distances the interaction remains unaffected.Comment: 8 pages, 2 figure

ERTS: A multispectral image analysis contribution for the geomorphological evaluation of southern Maracaibo Lake Basin

Multispectral analysis of ERTS-A images at scales of 1:1,000,000 and 1:500,000 has been conducted with conventional photointerpretation methods. Specific methods have been developed for the geomorphological analysis of southern Maracaibo Lake Basin which comprises part of the Venezuelan Andean Range, Perija Range, the Tachira gap and the Southern part of the Maracaibo Lake depression. A steplike analysis was conducted to separate macroforms, landscapes and relief units as well as drainage patterns and tectonic features, which permitted the delineation of tectonic provinces, stratigraphic units, geomorphologic units and geomorphologic positions. The geomorphologic synthesis obtained compares favorably with conventional analysis made on this area for accuracy of 1:100,000 scale, and in some features with details obtained through conventional analysis for accuracy of 1:15,000 and field work. Geomorphological units in the mountains were identified according to changes in tone, texture, forms orientation of interfluves and tectonic characteristics which control interfluvial disimetrics

Dark matter directional detection with MIMAC

MiMac is a project of micro-TPC matrix of gaseous (He3, CF4) chambers for direct detection of non-baryonic dark matter. Measurement of both track and ionization energy will allow the electron-recoil discrimination, while access to the directionnality of the tracks will open a unique way to distinguish a geniune WIMP signal from any background. First reconstructed tracks of 5.9 keV electrons are presented as a proof of concept.Comment: 4 pages, proc. of the 44th Rencontres De Moriond: Electroweak Interactions And Unified Theories, 7-14 Mar 2009, La Thuile, Ital

Entropy Rate of Diffusion Processes on Complex Networks

The concept of entropy rate for a dynamical process on a graph is introduced. We study diffusion processes where the node degrees are used as a local information by the random walkers. We describe analitically and numerically how the degree heterogeneity and correlations affect the diffusion entropy rate. In addition, the entropy rate is used to characterize complex networks from the real world. Our results point out how to design optimal diffusion processes that maximize the entropy for a given network structure, providing a new theoretical tool with applications to social, technological and communication networks.Comment: 4 pages (APS format), 3 figures, 1 tabl

Spontaneous symmetry breaking as a resource for noncritically squeezed light

In the last years we have proposed the use of the mechanism of spontaneous symmetry breaking with the purpose of generating perfect quadrature squeezing. Here we review previous work dealing with spatial (translational and rotational) symmetries, both on optical parametric oscillators and four-wave mixing cavities, as well as present new results. We then extend the phenomenon to the polarization state of the signal field, hence introducing spontaneous polarization symmetry breaking. Finally we propose a Jaynes-Cummings model in which the phenomenon can be investigated at the single-photon-pair level in a non-dissipative case, with the purpose of understanding it from a most fundamental point of view.Comment: Review for the proceedings of SPIE Photonics Europe. 11 pages, 5 figures

Prevalencia y prevención de las úlceras por presión en una cohorte de nonagenarios. Estudio NonaSantfeliu

IntroducciónEl envejecimiento progresivo de la población ha comportado un rápido aumento del grupo poblacional de los habitantes más ancianos, de manera que los > 89 años representan aproximadamente el 2% del total de > 65 años en España1. Las úlceras por presión (UPP) son un importante problema de salud por su prevalencia y morbilidad asociada2, que pueden afectar a pacientes en todos los ámbitos asistenciales. Una gran mayoría de ellas (alrededor del 70%)3 ocurren en personas > 70 años. Diversos estudios han mostrado que con una correcta implementación de políticas específicas destinadas a su prevención se consigue evitar su aparición en un considerable número de casos2,4.ObjetivosEvaluar en nuestro medio la prevalencia e incidencia de UPP en un grupo de población muy frágil, como son los nonagenarios, y comprobar la efectividad de un programa de prevención basado en recomendaciones para prevenir su aparición y enseñanza de los cuidados, cuando haya, para conseguir su curación.DiseñoEstudio de cohortes prospectivo.EmplazamientoCentros de atención primaria.ParticipantesEl trabajo se realizó dentro del estudio NonaSantfeliu, descrito ya previamente5. Se incluyó en el estudio inicial a 186 nonagenarios, el período de observación fue de 12 meses y se realizaron 2 evaluaciones al inicio y al final del período por parte del personal médico y/o de enfermería entrenado en la valoración geriátrica. Al año se revaluó a 140 nonagenarios; se excluyó a 36 participantes por haber fallecido y a 10 por cambio de domicilio.Mediciones principalesMediante entrevista personal, exploración a domicilio o en el centro de atención primaria cuando fue posible y posterior revisión de historia clínica, se recogieron datos sociodemográficos, actividades básicas de la vida diaria con el índice de Barthel (IB), cognición con el Miniexamen cognitivo de Lobo (MEC), comorbilidad con el índice de Charlson, riesgo de UPP con la escala de Braden con una puntuación 0-23 (< 12, alto riesgo), y valores de la version abreviada del Mini-Nutritional Assesment (MNA-SF) del año previo. El MNA-SF que puntúa de 0-14 (< 11 se considera riesgo nutricional) puede, al detectar pacientes de riesgo nutricional, ser útil para identificar a los pacientes con mayor incidencia de nuevas UPP.IntervencionesEducación sanitaria a los pacientes y cuidadores, para una correcta aplicación de medidas preventivas, y enseñanza de los cuidados necesarios para la cura de las UPP según la guía de UPP del Institut Català de Salut.ResultadosSe evaluó a 109 mujeres (77,8%) y 31 varones, con un promedio de edad al inicio del estudio de 92,7±2,8 años. En total, 114 eran viudos (81,5%), 14 (10%) estaban casados, y 12 (8,5%) eran solteros. La mayoría, 102 (73%), seguía viviendo en la comunidad y 38 estaban institucionalizados. Al final del período la media del IB era de 56,9±30,3, del MEC 22,4±11, del índice de Charlson de 1,1±1,5 y del MNA-SF de 11,4±2,1. Los valores medios de la escala de Braden eran de 15,5±2,4. El año previo, la prevalencia de UPP era del 7,1% (10) y al final del período de seguimiento, se habían curado todos los casos a excepción de un paciente. La incidencia de nuevas UPP fue del 3,5% (5 casos) con una prevalencia al año del 4,2% (3 mujeres y 3 varones). En la tabla 1 se puede observar las principales diferencias entre los pacientes con UPP al año de seguimiento y los pacientes sin UPP. En el análisis de regresión múltiple, tras ajustar por la edad y el sexo, la escala de Braden fue la única variable asociada significativamente con tener UPP en el momento de la evaluación (p=0,011; odds ratio [OR]=3,2; intervalo de confianza [IC] del 95%, 1,3-7,8).DiscusiónLas UPP han pasado de ser consideradas durante años un problema banal e inevitable a constituir en la actualidad un indicador de calidad asistencial debido a su gran impacto económico, tanto en el consumo de recursos humanos como materiales. La identificación de pacientes de riesgo y las recomendaciones preventivas son, sin duda, la mejor actuación para combatir las UPP2. El importante descenso observado en nuestro estudio, cercano al 50%, tras la implementación de medidas preventivas confirma la utilidad de la prevención, incluso en el paciente más anciano. Dado el reducido tamaño de la muestra, no se han observado diferencias en la prevalencia según el sexo, aunque se ha descrito una mayor prevalencia en mujeres6.ConclusionesLos programas de prevención de UPP son útiles en pacientes nonagenarios y debería intensificarse su implantación en los pacientes con riesgo en las escalas específicas para UPP, como la de Braden o con riesgo nutricional (MNASF)

Constraints on the three-fluid model of curvaton decay

A three fluid system describing the decay of the curvaton is studied by numerical and analytical means. We place constraints on the allowed interaction strengths between the fluids and initial curvaton density by requiring that the curvaton decays before nucleosynthesis while nucleosynthesis, radiation-matter equality and decoupling occur at correct temperatures. We find that with a continuous, time-independent interaction, a small initial curvaton density is naturally preferred along with a low reheating temperature. Allowing for a time-dependent interaction, this constraint can be relaxed. In both cases, a purely adiabatic final state can be generated, but not without fine-tuning. Unlike in the two fluid system, the time-dependent interactions are found to have a small effect on the curvature perturbation itself due to the different nature of the system. The presence of non-gaussianity in the model is discussed.Comment: 9 pages, 10 figure