2,664 research outputs found
Effect of supplementation with β-glucan of Saccharomyces cerevisiae and chito-oligosaccharides on digestion and growth performance in weanling rabbits
The aim of this work was to study the effect of yeast β-glucans and chito-oligosaccharides supplementation on digestion and growth performance of growing rabbits. Five experimental diets were prepared. A control diet was formulated with 18.1% protein, 33.1% neutral detergent fibre and 13% soluble fibre (on DM basis). Another four diets were obtained by supplementing control diet with β-glucans (200 or 400 ppm. BG2 and BG4) and chito-oligosaccharides (200 or 400 ppm. OT2 and OT4). No antibiotic was used. In the first experiment, 56 rabbits / treatment weighing 510 ± 73.0g weaned at 28 d of age were used to record mortality, and in 42 rabbits / treatment growth traits were recorded. Rabbits fed control, BG4 and OT4 diets (42/treatment), were used to determine the body composition by bioelectrical impedance technique measured at 28, 38 and 63 d of age. Experimental diets were offered from weaning up to 38 d of age. At this moment all rabbits were fed the control diet up to 63 d of age. Another group of 24 rabbits / treatment received from 28 to 38 d of age the five diets containing mordanced ytterbium. They were slaughtered at 38 d of age and ileal digesta collected to quantify ileal digestibility and caecal pH recorded. Faecal digestibility was measured from 36 to 38 d of age (9rabbits/diet). In the second experiment, three hundred thirty-four rabbits were separated from their mothers at 19 d of age (329 ± 65g) and assigned to the control, BG4 and OT4 diets. Rabbits suckled every morning for 10 minutes until 28 d of age. After weaning at 28 d of age, two hundred thirty-one rabbits received the same experimental diets than in the first period (77 rabbits per diet) and were caged individually to determine growth performance. At 19 d of age, 10 rabbits from 10 different litters were slaughtered to determine the digestive parameters (relative weight of total digestive tract, stomach and caecum ).At 27 and 38 d of age 30 rabbits(3 rabbits/treatment and litter) from each of the same 10 litters which have been chosen before (at 19 d of age) were slaughtered to determine the same measurements. Diet supplementation with β-glucans and chito-oligosaccharides did not affect ileal and faecal DM digestibility and faecal digestibility of fat, protein and fibre. Similarly, no treatment effect was found on growth traits along fattening period in the two experiments. In the first experiment, the mortality increased in rabbits supplemented with 200 ppm β-glucans compared to 400 ppm β-glucans (P = 0.048).In the second experiment, the mortality rates were lower than in the first one, and there were no other effect of treatments. The type of diet did not modify the retention and efficiency of both nitrogen and energy in the whole animal or in the carcass. However, rabbits fed supplemented diets with chito-oligosacchharides showed a higher faecal excretion of nitrogen (P=0.034) and energy (P=0.076) between 28 and 38d of age. Treatments had no effect on the relative weight of digestive organs. In conclusion, in our condition the supplementation of β-glucans and chito-oligosaccharides does not provide any advantage to growing rabbits
Sustained state-independent quantum contextual correlations from a single ion
We use a single trapped-ion qutrit to demonstrate the quantum-state-independent violation of noncontextuality inequalities using a sequence of randomly chosen quantum nondemolition projective measurements. We concatenate 53 × 106 sequential measurements of 13 observables, and unambiguously violate an optimal noncontextual bound. We use the same data set to characterize imperfections including signaling and repeatability of the measurements. The experimental sequence was generated in real time with a quantum random number generator integrated into our control system to select the subsequent observable with a latency below 50 μs, which can be used to constrain contextual hiddenvariable models that might describe our results. The state-recycling experimental procedure is resilient to noise and independent of the qutrit state, substantiating the fact that the contextual nature of quantum physics is connected to measurements and not necessarily to designated states. The use of extended sequences of quantum nondemolition measurements finds applications in the fields of sensing and quantum information
Tratamiento conservador en los hematomas intracerebrales supratentoriales espontáneos
Se realiza un estudio prospectivo de 50 pacientes diagnosticados por medio de tomografía computarizada craneal (TC) y angiografía carotídea de hematomas intracerebrales espontáneos (HIS) tratados de forma conservadora. Se analizan características clínicas y radiológicas de la fase aguda y la evolución de los pacientes durante el tiempo de ingreso hospitalario. La mortalidad global fue del 32%. Los factores que influyeron significativamente en el pronóstico fueron: el mayor grado de déficit motor al ingreso, el empeoramiento neural post-ingreso, el mayor volumen del hematoma y la presencia de efecto de masa en los estudios de TC y de angiografía carotídea. Todos los pacientes fueron evaluados clínicamente atendiendo a la escala de Glasgow para el Coma (EGC), con índice de mal pronóstico en todos aquellos que tenían una puntuación igual o inferior a ocho puntos. Se concluye que, de todos los factores evaluados en nuestro estudio, el volumen del hematoma con valor crítico de 50 ml y una puntuación menor de ocho puntos en la EGC son las principales causas en la mala evolución de estos enfermos
Risk factors for presentation to hospital with severe anaemia in Tanzanian children: a case-control study.
In malaria endemic areas anaemia is a usually silent condition that nevertheless places a considerable burden on health services. Cases of severe anaemia often require hospitalization and blood transfusions. The objective of this study was to assess risk factors for admission with anaemia to facilitate the design of anaemia control programmes. We conducted a prospective case-control study of children aged 2-59 months admitted to a district hospital in southern Tanzania. There were 216 cases of severe anaemia [packed cell volume (PCV) < 25%] and 234 age-matched controls (PCV > or = 25%). Most cases [55.6% (n = 120)] were < 1 year of age. Anaemia was significantly associated with the educational level of parents, type of accommodation, health-seeking behaviour, the child's nutritional status and recent and current medical history. Of these, the single most important factor was Plasmodium falciparum parasitaemia [OR 4.3, 95% confidence interval (CI) 2.9-6.5, P < 0.001]. Multivariate analysis showed that increased recent health expenditure [OR 2.2 (95% CI 1.3-3.9), P = 0.005], malnutrition [OR 2.4 (95%CI 1.3-4.3), P < 0.001], living > 10 km from the hospital [OR 3.0 (95% CI 1.9-4.9), P < 0.001], a history of previous blood transfusion [OR 3.8 (95% CI 1.7-9.1), P < 0.001] and P. falciparum parasitaemia [OR 9.5 (95% CI 4.3-21.3), P < 0.001] were independently related to risk of being admitted with anaemia. These findings are considered in terms of the pathophysiological pathway leading to anaemia. The concentration of anaemia in infants and problems of access to health services and adequate case management underline the need for targeted preventive strategies for anaemia control
What two models may teach us about duality violations in QCD
Though the operator product expansion is applicable in the calculation of
current correlation functions in the Euclidean region, when approaching the
Minkowskian domain, violations of quark-hadron duality are expected to occur,
due to the presence of bound-state or resonance poles. In QCD finite-energy sum
rules, contour integrals in the complex energy plane down to the Minkowskian
axis have to be performed, and thus the question arises what the impact of
duality violations may be. The structure and possible relevance of duality
violations is investigated on the basis of two models: the Coulomb system and a
model for light-quark correlators which has already been studied previously. As
might yet be naively expected, duality violations are in some sense "maximal"
for zero-width bound states and they become weaker for broader resonances whose
poles lie further away from the physical axis. Furthermore, to a certain
extent, they can be suppressed by choosing appropriate weight functions in the
finite-energy sum rules. A simplified Ansatz for including effects of duality
violations in phenomenological QCD sum rule analyses is discussed as well.Comment: 17 pages, 6 figures; version to appear in JHE
Modelización y caracterización de guías de ondas integradas multinúcleo codopadas con erbio e iterbio.
Las fibras multinúcleo (MCF) tienen un gran potencial para incrementar la capacidad de transmisión de información de los sistemas ópticos, mediante el multiplexado espacial (SDM) y modal (MDM), así como para aumentar la potencia de dispositivos ópticos activos mediante áreas modales grandes (LMA). Gracias a los avances recientes en la escritura de guías de onda con láseres de femtosegundo, es posible escribir estructuras multinúcleo en vidrios, permitiendo por tanto transferir las potencialidades de las fibras multinúcleo a dispositivos integrados. Estos pueden ser activos empleando vidrios dopado con tierras raras.La estructura multinúcleo más simple está formada por dos núcleos paralelos suficientemente cercanos como para que entre ellos exista intercambio de potencia óptica, y se suele utilizar como acoplador, sensor, convertidor modal o ecualizador espectral de ganancia. En esta tesis se han caracterizado este tipo de guías integradas escritas mediante láser de femtosegundos en un vidrio fosfatado codopado con erbio e iterbio. En primer lugar se ha llevado a cabo la caracterización de una guía individual para el posterior ajuste del modelo teórico, basado en las ecuaciones de la propagación de las potencias ópticas acopladas a las de la evolución temporal de las densidades de población de los niveles de energía. Una vez ajustado el modelo, se han realizado medidas de potencia óptica a la salida de las guías de dos núcleos en diferentes condiciones de excitación y en función de diversos parámetros (potencia de bombeo, separación entre núcleos, longitud de onda, etc) y se han comparado con las simulaciones. Se ha encontrado que el modelo teórico reproduce adecuadamente las medias realizadas, excepto en unas condiciones de alta asimetría en las que se observa una dependencia experimental desconocida hasta la fecha según nuestro conocimiento. En estas condiciones ha sido necesario tener en cuenta un nuevo formalismo matemático basado en la teoría de modos acoplados (TMA) que, tras identificar los parámetros más críticos y su influencia, permite reproducir razonablemente bien las medidas realizadas.Una de las características típicas de las guías multinúcleo es su comportamiento multimodal, para cuyo diseño y optimización resulta fundamental realizar un correcto análisis modal que, además, permite estudiar el mecanismo de la competición entre modos y el acoplamiento entre estos. Teniendo en cuenta su interés, se ha puesto a punto un montaje experimental de determinación del porcentaje de potencia total y fase relativa de cada modo transversal en guías de ondas usando un modulador espacial de luz (SLM), y se ha implementado para el análisis de los modos de una fibra óptica estándar en el visible. Junto con su implementación y correcta comprobación experimental se ha llevado a cabo un estudio numérico sobre el impacto de diferentes parámetros en la relación señal-ruido obtenida en el proceso de análisis modal.Por último, se han estudiado dos aplicaciones basadas en guías multinúcleo activas: el diseño optimizado de un amplificador basado en una guía de onda óptica por reflexión antirresonante en un medio dopado con erbio, y la viabilidad de mejorar las prestaciones de un sensor de curvatura, basado en la interferencia modal en una fibra multinúcleo, mediante la implementación de una etapa activa.<br /
Soft power y nueva diplomacia china en el siglo XXI con países del sur global: el caso latinoamericano
The research analyzes China's positioning process at regional and global level, and the instruments it has implemented to assume international leadership: soft power and new cultural diplomacy as part of the process of transforming its foreign policy. This policy is expressed in various roles he has played, as a conciliator in regional conflicts, as a member of multilateral instruments at a global and regional level within Asia. All of the above, in the context of the United States withdrawal from the global agenda. Which implies that China, as a power, has sought through various mechanisms to have approaches with industrialized economies such as the European Union and with emerging economies in Latin America. Therefore, in their commercial expansion project called the New Silk Road, the European Union and Latin America play an important role.La investigación analiza el proceso de posicionamiento de China a nivel regional y global, y los instrumentos que ha implementado para asumir el liderazgo internacional: el soft power y la nueva diplomacia cultural como parte del proceso de transformación de su política exterior. Esta política se expresa en diversos papeles que ha desempeñado, como conciliador en conflictos regionales, como miembro de instrumentos multilaterales a nivel global y regional al interior de Asia. Todo lo anterior, en el contexto de la retirada de Estados Unidos de la agenda global. Lo que implica que China, como potencia, ha buscado a través de diversos mecanismos tener acercamientos con economías industrializadas como la Unión Europea y con economías emergentes de América Latina. Por ello, en su proyecto de expansión comercial denominado la Nueva Ruta de la Seda, la Unión Europea y América Latina juegan un papel relevante
DNA content of a functioning chicken kinetochore
© The Author(s) 2014. In order to understand the three-dimensional structure of the functional kinetochore in vertebrates, we require a complete list and stoichiometry for the protein components of the kinetochore, which can be provided by genetic and proteomic experiments. We also need to know how the chromatin-containing CENP-A, which makes up the structural foundation for the kinetochore, is folded, and how much of that DNA is involved in assembling the kinetochore. In this MS, we demonstrate that functioning metaphase kinetochores in chicken DT40 cells contain roughly 50 kb of DNA, an amount that corresponds extremely closely to the length of chromosomal DNA associated with CENP-A in ChIP-seq experiments. Thus, during kinetochore assembly, CENP-A chromatin is compacted into the inner kinetochore plate without including significant amounts of flanking pericentromeric heterochromatin. © 2014 The Author(s).Wellcome Trust [grant number 073915]; Wellcome Trust Centre for Cell Biology (core grant numbers 077707 and 092076); Darwin Trust of Edinburg
Características morfológicas del círculo arterial del cerebro en fallecidos por infarto cerebral
Se realiza un estudio en el Hospital General Docente “Dr. Agostinho Neto” de Guantánamo con el objetivo de describir características morfométricas del círculo arterial del cerebro en 30 fallecidos por infarto cerebral, de febrero a julio de 2008. La información fue procesada utilizando paquete estadístico SPSS V. 10.0. Se determina frecuencia absoluta, porcentaje de variables cualitativas, media y desviación estándar para longitud de arterias cerebrales que conforman el círculo del cerebro. Predomina el sexo masculino, grupo de edades de 80 años y más, color de piel mestizo, antecedentes de hipertensión arterial y fumadores. No se muestra diferencias estadísticamente significativas al comparar valores de longitud media de arterias que forman círculo arterial del cerebro, El círculo arterial de los fallecidos estaba modificado manifestándose en el aspecto delgado de las arterias que aparecieron mayoritariamente en arterias comunicantes posteriores derechas, en fallecidos del sexo femenino, en mestizos y fumadores
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