951 research outputs found

    Intestinal epithelial barrier and mucosal immunity

    Get PDF
    Intestinal mucosa integrates primary digestive functions with immune functions such as pathogen surveillance, antigen transport and induction of mucosal immunity and tolerance. Intestinal adaptive immunity is elicited in organized mucosa-associated lymphoid tissue (O-MALT) that is composed of antigen-presenting cells and lymphocytes and achieved by effector cells widely distributed in mucosa (diffuse MALT or D-MALT). Interaction between the intestinal epithelium, the O-MALT and the diffuse MALT plays a critical role in establishing an adequate immune response. In regions associated to O-MALT, lympho-epithelial cross-talks lead to acquisition of a specific epithelial phenotype that contributes to O-MALT organization and functionality. Beyond the expression of several innate immune functions, the intestinal epithelium may directly take up and present antigens due to the expression of major histocompatibility complex (MHC) and MHC-related molecules. A complex genetic program that will be outlined in the present review controls the development of immune functions of the intestinal epithelium. The effect of environmental signals on the modulation of this ontogenetic program during development and neonatal life, from bioactive components of amniotic fluid to lactation and bacterial colonization, will be discussed.Facultad de Ciencias Exacta

    Physical qubits from charged particles: IR divergences in quantum information

    Get PDF
    We consider soft photons effects (IR structure of QED) on the construction of physical qubits. Soft-photons appear when we build charged qubits from the asymptotic states of QED. This construction is necessary in order to include the effect of soft photons on entanglement measures. The nonexistence of free charged particles (due to the long range of QED interactions) lead us to question the sense of the very concept of free charged qubit. In this letter, using the "dressing" formalism, we build physical charged qubits from dressed fields which have the correct asymptotic behavior, are gauge invariant, their propagators have a particle pole structure and are free from infrared divergences. Finally, we discuss the impact of the soft corrections on the entanglement measures.Comment: 4 pages, 2 figures, RevTeX. Version 2: Some references update

    In the margins of intercultural education. Institutional order in the school, cultural diversity and attention to singularity

    Get PDF
    Lo que presentamos en este texto es una reflexión pedagógica acerca del tratamiento que la escuela da a la diversidad cultural, a partir de un estudio reciente sobre la experiencia escolar de éxito de alumnas inmigradas (Caparrós, 2014). En él nos planteamos la posibilidad de reflexionar sobre lo que hay detrás de la pregunta por las voces silenciadas dentro de un estudio que habla de alumnas inmigradas con éxito. Como hemos podido conocer, la diversidad cultural parece tenerse en cuenta únicamente cuando genera problemas de rendimiento escolar y/o de convivencia, o sea, problemas de adaptación a la cultura escolar en sus diferentes concreciones prácticas y simbólicas. Cuando la diversidad cultural, como ocurre para los dos casos estudiados, no significa un lastre para el progreso escolar, parecen importar poco los entresijos biográficos y los bagajes culturales de las estudiantes. Algo que entendemos como una señal de alerta para volver a pensar el modelo de atención a la diversidad que pervive en los centros; un modelo más cercano a planteamientos multiculturales (cuando no asimilacionistas). Bajo esta óptica, la escuela parece tener una mirada etnocéntrica que se ampara en un orden institucional más preocupado por la igualdad que por las diferencias. Ante este análisis que une el éxito escolar a la diversidad cultural, nos parece más adecuado hablar de voces desatendidas, en lugar de voces silenciadas: el matiz está en cómo aun siendo buenas estudiantes la escuela es incapaz de apreciar en cada una de las alumnas sus singularidades (incluida ahí su diversidad cultural). Lo que planteamos entonces es la posibilidad de desplazarnos de las etiquetas, los tópicos, los temas, para ir hacia lo que la experiencia vivida nos dice acerca de “lo intercultural”. Así pues, la investigación de la experiencia nos abre y nos expone hacia la alteridad, una tarea exigente pedagógicamente. Es por ello que la consideramos rica en posibilidades de transformación en lo que respecta al estudio de la(s) cultura(s) en la escuela

    Unveiling quantum entanglement degradation near a Schwarzschild black hole

    Get PDF
    We analyze the entanglement degradation provoked by the Hawking effect in a bipartite system Alice-Rob when Rob is in the proximities of a Schwarzschild black hole while Alice is free falling into it. We will obtain the limit in which the tools imported from the Unruh entanglement degradation phenomenon can be used properly, keeping control on the approximation. As a result, we will be able to determine the degree of entanglement as a function of the distance of Rob to the event horizon, the mass of the black hole, and the frequency of Rob's entangled modes. By means of this analysis we will show that all the interesting phenomena occur in the vicinity of the event horizon and that the presence of event horizons do not effectively degrade the entanglement when Rob is far off the black hole. The universality of the phenomenon is presented: There are not fundamental differences for different masses when working in the natural unit system adapted to each black hole. We also discuss some aspects of the localization of Alice and Rob states. All this study is done without using the single mode approximation.Comment: 16 pages, 10 figures, revtex4. Added Journal referenc

    Thermalization of particle detectors: The Unruh effect and its reverse

    Get PDF
    11 pags., 3 figs., app.We study the anti-Unruh effect in general stationary scenarios. We find that, for accelerated trajectories, a particle detector coupled to a Kubo-Martin-Schwinger (KMS) state of a quantum field can cool down (click less often) as the KMS temperature increases. Remarkably, this is so even when the detector is switched on adiabatically for infinitely long times. We also show that the anti-Unruh effect is characteristic of accelerated detectors and cannot appear for inertially moving detectors (e.g., in a thermal bath). © 2016 American Physical SocietyL. J. G. was partially supported by the Spanish MINECO through Project No. FIS2014-54800-C2-2 (with FEDER contribution). E. M.-M. acknowledges the funding of the NSERC Discovery program.Peer Reviewe

    Anthropometric measures as predictive indicators of metabolic risk in a population of “holy week costaleros”

    Get PDF
    Preventive measures are a priority in those groups that perform intense physical efforts without physical preparation and that can also be overweight or obese. One of the groups that reflect these characteristics is the costaleros of the Holy Week of Andalusia, Spain. This paper aims to describe the effect of obesity on blood pressure. A descriptive cross-sectional study was conducted on 101 costaleros. The anthropometric measures were determined through segmental impedance. Cardiac recovery and anaerobic power were measured through the Ruffier–Dickson test and the Abalakov test, respectively. Blood pressure was measured when the individuals were at rest. The Kruskal–Wallis test was applied for of continuous parameters and the X2 test for dichotomous measures. Binary logistic regression models were used for the subsequent analysis with R-square and Receiver Operating Characteristic (ROC) curves. The average population was 28 years of age, 173.7 cm tall, and 82.59 Kg weigh. The excess of body fat was 11.27 Kg and Body Mass Index was 27.33 Kg/m2. 72.3% showed abnormal blood pressure and 68.2% were overweight. 32.7% had a waist-hip ratio higher than 0.94. The probability of presenting abnormal blood pressure was higher among the subjects whose fat content was higher and muscle content was lower

    Generation of raptor diversity in Europe: Linking speciation with climate changes and the ability to migrate

    Full text link
    Europe holds a rich community of diurnal birds of prey, and the highest proportion of transcontinental migratory raptorial species of any landmass. This study will test the hypotheses that the high diversification of the raptor assemblage in Europe is a recent event, that closely related species sharing the same trophic niches can only coexist in sympatry during the breeding period, when food availability is higher, and finally that migration is a function of size, with the smaller species in every trophic group moving further. A consensus molecular phylogeny for the 38 regular breeding species of raptors in Europe was obtained from BirdTree (www.birdtree.org). For the same species, a trophic niche cluster dendrogram was constructed. Size and migratory strategy were introduced in the resulting phylogeny, where trophic groups were also identified. Multispecific trophic groups tended to be composed of reciprocal sister species of different sizes, while monospecific groups (n = 3) were composed of highly specialized species. Many speciation events took place recently, during the glacial cycles of the Quaternary, and size divergence among competing species may be due to character displacement. Nowadays, the smaller species in every trophic group migrate to sub-Saharan Africa. This investigation illustrates how the rich assemblage of diurnal birds of prey in Europe, more diverse and more migratory than, for instance, the North American assemblage at equivalent latitudes, has emerged recently due to the multiplication of look-alike species with similar trophic ecologies, possibly in climate refugia during cold period

    The interleukin-6 and noradrenaline mediated inflammation-stress feedback mechanism is dysregulated in metabolic syndrome: Effect of exercise

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Metabolic syndrome (MS) is a metabolic disorder associated with obesity, type-II diabetes, and "low grade inflammation", with the concomitant increased risk of cardiovascular events. Removal of the inflammatory mediator signals is a promising strategy to protect against insulin resistance, obesity, and other problems associated with MS such as cardiovascular disease. The aim of the present investigation was to determine the "inflammatory and stress status" in an experimental model of MS, and to evaluate the effect of a program of habitual exercise and the resulting training-induced adaptation to the effects of a single bout of acute exercise.</p> <p>Methods</p> <p>Obese Zucker rats (fa/fa) were used as the experimental model of MS, and lean Zucker rats (Fa/fa) were used for reference values. The habitual exercise (performed by the obese rats) consisted of treadmill running: 5 days/week for 14 weeks, at 35 cm/s for 35 min in the last month. The acute exercise consisted of a single session of 25-35 min at 35 cm/s. Circulating concentrations of IL-6 (a cytokine that regulates the inflammatory and metabolic responses), CRP (a systemic inflammatory marker), and corticosterone (CTC) (the main glucocorticoid in rats) were determined by ELISA, and that of noradrenaline (NA) was determined by HPLC. Glucose was determined by standard methods.</p> <p>Results</p> <p>The genetically obese animals showed higher circulating levels of glucose, IL-6, PCR, and NA compared with the control lean animals. The habitual exercise program increased the concentration of IL-6, PCR, NA, and glucose, but decreased that of CTC. Acute exercise increased IL-6, CRP, and NA in the sedentary obese animals, but not in the trained obese animals. CTC was increased after the acute exercise in the trained animals only.</p> <p>Conclusion</p> <p>Animals with MS present a dysregulation in the feedback mechanism between IL-6 and NA which can contribute to the systemic low-grade inflammation and/or hyperglycaemia of MS. An inappropriate exercise intensity can worsen this dysregulation, contributing to the metabolic, inflammatory, and stress disorders associated with MS. Habitual exercise (i.e., training) induces a positive adaptation in the response to acute exercise.</p

    The entangling side of the Unruh-Hawking effect

    Full text link
    We show that the Unruh effect can create net quantum entanglement between inertial and accelerated observers depending on the choice of the inertial state. This striking result banishes the extended belief that the Unruh effect can only destroy entanglement and furthermore provides a new and unexpected source for finding experimental evidence of the Unruh and Hawking effects.Comment: 4 pages, 4 figures. Added Journal referenc

    Berry Phase Quantum Thermometer

    Get PDF
    We show how Berry phase can be used to construct an ultra-high precision quantum thermometer. An important advantage of our scheme is that there is no need for the thermometer to acquire thermal equilibrium with the sample. This reduces measurement times and avoids precision limitations.Comment: Updated to published version. I. Fuentes previously published as I. Fuentes-Guridi and I. Fuentes-Schulle
    corecore