Stable oxygen isotope record and lithogenic composition of ODP Hole 117-722B

The upper 38 m of Hole 722B sediments (Owen Ridge, northwest Arabian Sea) was sampled at 20 cm intervals and used to develop records of lithogenic percent, mass accumulation rate, and grain size spanning the past 1 m.y. Over this interval, the lithogenic component of Owen Ridge sediments can be used to infer variability in the strength of Arabian Sea summer monsoon winds (median grain size) and the aridity of surrounding dust source-areas (mass accumulation rate; MAR in g/cm**2/k.y). The lithogenic MAR has strong 100, 41, and 23 k.y. cyclicities and is forced primarily by changes in source-area aridity associated with glacial-interglacial cycles. The lithogenic grain size, on the other hand, exhibits higher frequency variability (23 k.y.) and is forced by the strength of summer monsoon winds which, in turn, are forced by the effective sensible heating of the Indian-Asian landmass and by the availability of latent heat from the Southern Hemisphere Indian Ocean. These forcing mechanisms combine to produce a wind-strength record which has no strong relationship to glacial-interglacial cycles. Discussion of the mechanisms responsible for production of primary Milankovitch cyclicities in lithogenic records from the Owen Ridge is presented elsewhere (Clemens and Prell, 1990, doi:10.1029/PA005i002p00109). Here we examine the 1 m.y. record from Hole 722B focusing on different aspects of the lithogenic components including an abrupt change in the monsoon wind-strength record at 500 k.y., core-to-core reproducibility, comparison with magnetic susceptibility, coherency with a wind-strength record from the Pacific Ocean, and combination frequencies in the wind-strength record. The Hole 722B lithogenic grain-size record shows an abrupt change at 500 k.y. possibly indicating decreased monsoon wind-strength over the interval from 500 k.y. to present. The grain-size decrease appears to be coincident with a loss of spectral power near the 41 k.y. periodicity. However, the grain-size decrease is not paralleled in the Globigerina bulloides upwelling record, an independent record of summer monsoon wind-strength (Prell, this volume). These observations leave us with competing hypotheses possibly involving: (1) a decrease in the sensitivity of monsoon windstrength to obliquity forcing, (2) decoupling of the grain size and G. bulloides records via a decoupling of the nutrient supply from wind-driven upwelling, and/or (3) a change in dust source-area or the patterns of dust transporting winds. Comparison of the lithogenic grain size and weight percent records from Hole 722B with those from a nearby core shows that the major and most minor events are well replicated. These close matches establish our confidence in the lithogenic extraction techniques and measurements. Further, reproducibility on a core-to-core scale indicates that the eolian depositional signal is regionally strong, coherent, and well preserved. The lithogenic weight percent and magnetic susceptibility are extremely well correlated in both the time and frequency domains. From this we infer that the magnetically susceptible component of Owen Ridge sediments is of terrestrial origin and transported to the Owen Ridge via summer monsoon winds. Because of the high correlation with the lithogenic percent record, the magnetic susceptibility record can be cast in terms of lithogenic MAR and used as a high resolution proxy for continental aridity. In addition to primary Milankovitch periodicities, the Hole 722B grain-size record exhibits periodicity at 52 k.y. and at 29 k.y. Both periodicities are also found in the grain-size record from piston core RC11-210 in the equatorial Pacific Ocean. Comparison of the two grain-size records shows significant coherence and zero phase relationships over both the 52 and 29 k.y. periodicities suggesting that the strengths of the Indian Ocean monsoon and the Pacific southeasterly trade winds share common forcing mechanisms. Two possible origins for the 52 and 29 k.y. periodicities in the Hole 722B wind-strength record are (1) direct Milankovitch forcing (54 and 29 k.y. components of obliquity) and (2) combination periodicities resulting from nonlinear interactions within the climate system. We find that the 52 and 29 k.y. periodicities show stronger coherency with crossproducts of eccentricity and obliquity (29 k.y.) and precession and obliquity (52 k.y.) than with direct obliquity forcing. Our working hypothesis attributes these periodicities to nonlinear interaction between external insolation forcing and internal climatic feedback mechanisms involving an interdependence of continental snow/ice-mass (albedo) and the hydrological cycle (latent heat availability).

Thermal reaction norms of growth in Atlantic and Pacific silverside fishes

How organisms may adapt to rising global temperatures is uncertain, but concepts can emerge from studying adaptive physiological trait variations across existing spatial climate gradients. Many ectotherms, particularly fish, have evolved increasing genetic growth capacities with latitude (i.e. countergradient variation (CnGV) in growth), which are thought to be an adaptation primarily to strong gradients in seasonality. In contrast, evolutionary responses to gradients in mean temperature are often assumed to involve an alternative mode, 'thermal adaptation'. We measured thermal growth reaction norms in Pacific silverside populations (Atherinops affinis) occurring across a weak latitudinal temperature gradient with invariant seasonality along the North American Pacific coast. Instead of thermal adaptation, we found novel evidence for CnGV in growth, suggesting that CnGV is a ubiquitous mode of reaction-norm evolution in ectotherms even in response to weak spatial and, by inference, temporal climate gradients. A novel, large-scale comparison between ecologically equivalent Pacific versus Atlantic silversides (Menidia menidia) revealed how closely growth CnGV patterns reflect their respective climate gradients. While steep growth reaction norms and increasing growth plasticity with latitude in M. menidia mimicked the strong, highly seasonal Atlantic coastal gradient, shallow reaction norms and much smaller, latitude-independent growth plasticity in A. affinis resembled the weak Pacific latitudinal temperature gradient.

Seawater carbonate chemistry and Globigerinoides sacculifer biological processes during experiments, 2010

The effect of carbonate ion concentration ([CO3]) on calcification rates estimated from shell size and weight was investigated in the planktonic foraminifera Orbulina universa and Globigerinoides sacculifer. Experiments on G. sacculifer were conducted under two irradiance levels (35 and 335 µmol photons m-2 s-1). Calcification was ca. 30% lower under low light than under high light, irrespective of the [CO3]. Both O. universa and G. sacculifer exhibited reduced final shell weight and calcification rate under low [CO3]. For the [CO3] expected at the end of the century, the calcification rates of these two species are projected to be 6 to 13% lower than the present conditions, while the final shell weights are reduced by 20 to 27% for O. universa and by 4 to 6% for G. sacculifer. These results indicate that ocean acidification would impact on calcite production by foraminifera and may decrease the calcite flux contribution from these organisms.

Ingestion rate and egg production of copepods collected in the upper 20m in the eastern Mediterranean Sea in March and April 2008 during SES_GR1

The ingestion on ciliates and phytoplankton dataset is based on samples taken during April 2008 in Northern Aegean Sea, the area influenced by the Black Sea water outflow. A Lagrangian experiment was established and copepod ingestion was estimated from experiments performed at stations according to the different positions of drifters during the cruise. Copepods for the experiments were obtained with slow non-quantitative tows from the upper 20 m layer of the water column using 200 µm mesh size nets fitted with a large non-filtering cod end. For the grazing experiments we used the following copepod species: Centropages typicus and Calanus helgolandicus according to the relevant reference (Bamstedt et al. 2000). Copepod clearance rates on ciliates were calculated according to Frost equations (Frost 1972). Ingestion rates were calculated by multiplying clearance rates by the initial standing stocks (Bamstedt et al. 2000). The egg production dataset is based on samples taken during April 2008 in Northern Aegean Sea, the area influenced by the Black Sea water outflow. A Lagrangian experiment was established and copepod egg production was estimated from experiments performed at stations according to the different positions of drifters during the cruise. Egg production rates of the dominant calanoid copepods were determined by incubation of fertilised females (eggs female/day) collected in the 0-20m layer. Copepod egg production was measured for the copepods Centropages typicus, Calanus helgolandicus. On board experiments for the estimation of copepod egg production were taken place. For the estimation of copepod production (mgC/ m**2 /day), lengths (copepods and eggs) were converted to body carbon (Hopcroft et al., 1998) and production was estimated from biomass and weight-specific egg production rates, by assuming that those rates are representative for juvenile specific growth rates (Berggreen et al., 1988).

Ingestion rate and egg production of copepods collected in the upper 20m in the eastern Mediterranean Sea in Oktober 2008

This dataset based on samples taken during October 2008 in Dardanelles Straits, Marmara Sea and Bosporus Straits at the third priority stations. Copepods for the experiments were obtained with slow non-quantitative tows from the upper 50 m layer of the water column using 200 µm mesh size nets fitted with a large non-filtering cod end. For the grazing experiments we used the following copepod species: Oithona spp., Clausocalanus furcatus, Acartia clausi and Oncaea spp. and in one cladoceran species Penilia avirostris according to the relevant reference (Bamstedt et al. 2000). Copepod clearance rates on ciliates were calculated according to Frost equations (Frost 1972). Ingestion rates were calculated by multiplying clearance rates by the initial standing stocks (Bamstedt et al. 2000). Egg production rates of the dominant calanoid copepods were determined by incubation of fertilised females (eggs/female/day) collected in the 0-20m layer. Copepod egg production was measured for the copepods Clausocalanus furcatus, Paracalanus parvus,Acaria clausi. On board experiments for the estimation of copepod egg production were taken place. For the estimation of copepod production (mg/m**2/day), lengths (copepods and eggs) were converted to body carbon (Hopcroft et al., 1998) and production was estimated from biomass and weight-specific egg production rates, by assuming that those rates are representative for juvenile specific growth rates (Berggreen et al., 1988).

Ingestion rate and egg production of copepods collected in the upper 100m in the eastern Mediterranean Sea in March and April 2008 during SES_GR1

The phytoplankton dataset is based on samples taken during March-April 2008 in Libyan Sea, Southern Aegean Sea and Northern Aegean Sea. Ingestion rates were estimated from experiments performed at all the third priority stations during the cruise according to DoW of Sesame project. Copepods for the experiments were obtained with slow non-quantitative tows from the upper 100 m layer of the water column using 200 µm mesh size nets fitted with a large non-filtering cod end. For the grazing experiments we used the following copepod species: Calanus helgolandicus and Centropages typicus according to the relevant reference (Bamstedt et al. 2000). Copepod clearance rates on ciliates were calculated according to Frost equations (Frost 1972). Ingestion rates were calculated by multiplying clearance rates by the initial standing stocks (Bamstedt et al. 2000). Egg production rates of the dominant calanoid copepods were determined by incubation of fertilised females (eggs/female/day) collected in the 0-100m layer. Copepod egg production was measured for the copepods Eucalanus monachus, Centropages typicus and Calanus helgolandicus. On board experiments for the estimation of copepod egg production were taken place. For the estimation of copepod production (mg/m**2/day), lengths (copepods and eggs) were converted to body carbon (Hopcroft et al., 1998) and production was estimated from biomass and weight-specific egg production rates, by assuming that those rates are representative for juvenile specific growth rates (Berggreen et al., 1988).

Determinant factors to discriminate the body weight loss in overweight people

Introduction. Most studies have described how the weight loss is when different treatments are compared (1-3), while others have also compared the weight loss by sex (4), or have taken into account psychosocial (5) and lifestyle (6, 7) variables. However, no studies have examined the interaction of different variables and the importance of them in the weight loss. Objective. Create a model to discriminate the range of weight loss, determining the importance of each variable. Methods. 89 overweight people (BMI: 25-29.9 kg?m-2), aged from 18 to 50 years, participated in the study. Four types of treatments were randomly assigned: strength training (S), endurance training (E), strength and endurance training (SE), and control group (C). All participants followed a 25% calorie restriction diet. Two multivariate discriminant models including the variables age, sex, height, daily energy expenditure (EE), type of treatment (T), caloric restriction (CR), initial body weight (BW), initial fat mass (FM), initial muscle mass (MM) and initial bone mineral density (BMD) were performed having into account two groups: the first and fourth quartile of the % of weight loss in the first model; the groups above and below the mean of the % of weight loss in the second model. The discriminant models were built using the inclusion method in SPSS allowing us to find a function that could predict the body weight loss range that an overweight person could achieve in a 6 months weight loss intervention.Results. The first discriminant analysis predicted that a combination of the studied variables would discriminate between the two ranges of body weight loss with 81.4% of correct classification. The discriminant function obtained was (Wilks? Lambda=0.475, p=0.003): Discriminant score=-18.266-(0.060xage)- (1.282xsex[0=female;1=male])+(14.701xheight)+(0.002xEE)- (0.006xT[1=S;2=E;3=SE;4=C])-(0.047xCR)- (0.558xBW)+(0.475xFM)+(0.398xMM)+(3.499xBMD) The second discriminant model obtained would discriminate between the two groups of body weight loss with 74.4% of correct classification. The discriminant function obtained was (Wilks? Lambda=0.725, p=0.005): Discriminant score=-5.021-(0.052xage)- (0.543xsex[0=female;1=male])+(3.530xheight)+(0.001xEE)- (0.493xT[1=S;2=E;3=SE;4=C])+(0.003xCR)- (0.365xBW)+(0.368xFM)+(0.296xMM)+(4.034xBMD) Conclusion. The first developed model could predict the percentage of weight loss in the following way: if the discriminant score is close to 1.051, the range of weight loss will be from 7.44 to -4.64% and if it is close to - 1.003, the range will be from -11.03 to -25,00% of the initial body weight. With the second model if the discriminant score is close to 0.623 the body weight loss will be above -7.93% and if it is close to -0.595 will be below - 7.93% of the initial body weight. References. 1. Brochu M, et al. Resistance training does not contribute to improving the metabolic profile after a 6-month weight loss program in overweight and obese postmenopausal women. J Clin Endocrinol Metab. 2009 Sep;94(9):3226-33. 2. Del Corral P, et al. Effect of dietary adherence with or without exercise on weight loss: a mechanistic approach to a global problem. J Clin Endocrinol Metab. 2009 May;94(5):1602-7. 3. Larson-Meyer DE, et al. Caloric Restriction with or without Exercise: The Fitness vs. Fatness Debate. Med Sci Sports Exerc. 2010;42(1):152-9. 4. Hagan RD, et al. The effects of aerobic conditioning and/or caloric restriction in overweight men and women. Medicine & Science in Sports & Exercise. 1986;18(1):87-94. 5. Teixeira PJ, et al. Mediators of weight loss and weight loss maintenance in middle-aged women. Obesity (Silver Spring). 2010 Apr;18(4):725-35. 6. Bautista-Castano I, et al. Variables predictive of adherence to diet and physical activity recommendations in the treatment of obesity and overweight, in a group of Spanish subjects. Int J Obes Relat Metab Disord. 2004 May;28(5):697-705.

Simulation, Design and Analysis of Air-Breathing Combined-Cycle Engines for High Speed Propulsion

Desde la aparición del turborreactor, el motor aeróbico con turbomaquinaria ha demostrado unas prestaciones excepcionales en los regímenes subsónico y supersónico bajo. No obstante, la operación a velocidades superiores requiere sistemas más complejos y pesados, lo cual ha imposibilitado la ejecución de estos conceptos. Los recientes avances tecnológicos, especialmente en materiales ligeros, han restablecido el interés por los motores de ciclo combinado. La simulación numérica de estos nuevos conceptos es esencial para estimar las prestaciones de la planta propulsiva, así como para abordar las dificultades de integración entre célula y motor durante las primeras etapas de diseño. Al mismo tiempo, la evaluación de estos extraordinarios motores requiere una metodología de análisis distinta. La tesis doctoral versa sobre el diseño y el análisis de los mencionados conceptos propulsivos mediante el modelado numérico y la simulación dinámica con herramientas de vanguardia. Las distintas arquitecturas presentadas por los ciclos combinados basados en sendos turborreactor y motor cohete, así como los diversos sistemas comprendidos en cada uno de ellos, hacen necesario establecer una referencia común para su evaluación. Es más, la tendencia actual hacia aeronaves "más eléctricas" requiere una nueva métrica para juzgar la aptitud de un proceso de generación de empuje en el que coexisten diversas formas de energía. A este respecto, la combinación del Primer y Segundo Principios define, en un marco de referencia absoluto, la calidad de la trasferencia de energía entre los diferentes sistemas. Esta idea, que se ha estado empleando desde hace mucho tiempo en el análisis de plantas de potencia terrestres, ha sido extendida para relacionar la misión de la aeronave con la ineficiencia de cada proceso involucrado en la generación de empuje. La metodología se ilustra mediante el estudio del motor de ciclo combinado variable de una aeronave para el crucero a Mach 5. El diseño de un acelerador de ciclo combinado basado en el turborreactor sirve para subrayar la importancia de la integración del motor y la célula. El diseño está limitado por la trayectoria ascensional y el espacio disponible en la aeronave de crucero supersónico. Posteriormente se calculan las prestaciones instaladas de la planta propulsiva en función de la velocidad y la altitud de vuelo y los parámetros de control del motor: relación de compresión, relación aire/combustible y área de garganta. ABSTRACT Since the advent of the turbojet, the air-breathing engine with rotating machinery has demonstrated exceptional performance in the subsonic and low supersonic regimes. However, the operation at higher speeds requires further system complexity and weight, which so far has impeded the realization of these concepts. Recent technology developments, especially in lightweight materials, have restored the interest towards combined-cycle engines. The numerical simulation of these new concepts is essential at the early design stages to compute a first estimate of the engine performance in addition to addressing airframe-engine integration issues. In parallel, a different analysis methodology is required to evaluate these unconventional engines. The doctoral thesis concerns the design and analysis of the aforementioned engine concepts by means of numerical modeling and dynamic simulation with state-of-the-art tools. A common reference is needed to evaluate the different architectures of the turbine and the rocket-based combined-cycle engines as well as the various systems within each one of them. Furthermore, the actual trend towards more electric aircraft necessitates a common metric to judge the suitability of a thrust generation process where different forms of energy coexist. In line with this, the combination of the First and the Second Laws yields the quality of the energy being transferred between the systems on an absolute reference frame. This idea, which has been since long applied to the analysis of on-ground power plants, was extended here to relate the aircraft mission with the inefficiency of every process related to the thrust generation. The methodology is illustrated with the study of a variable- combined-cycle engine for a Mach 5 cruise aircraft. The design of a turbine-based combined-cycle booster serves to highlight the importance of the engine-airframe integration. The design is constrained by the ascent trajectory and the allocated space in the supersonic cruise aircraft. The installed performance of the propulsive plant is then computed as a function of the flight speed and altitude and the engine control parameters: pressure ratio, air-to-fuel ratio and throat area.

Thermomechanical relaxation and different water states in cottonseed protein derived bioplastics

Thermomechanical relaxation events and different water states in cottonseed protein bioplastics are presented whilst investigating the effects of aldehyde cross-linking agents. Thermomechanical relaxation of cottonseed protein bioplastics associated with protein denaturation, moisture absorption and broad glass transitions (Tg) were observed from DSC and DMA measurements. It was shown that variation of the aldehyde influences the storage modulus at very low temperature (below Tg). From measurements of the water fusion point, enthalpy, vaporisation, and weight loss, three water states in the water-absorbed bioplastics are suggested; namely strongly-bound-to-polymer, weakly-bound-to-polymer and bulk-like water. The water content and unreacted cross-linking agents are influential factors in controlling formation of the different water states, whilst the selection of different aldehydes was found to be negligible. These results could be valuable for adjusting the thermomechanical relaxations of protein based bioplastics, and tailoring their properties in wet environments.

Partioning of dietary energy of chickens fed maize or wheat-based diets with and without a commercial blend of phytogenic feed additives

The aim of the study was to investigate the effects of a standardized mixture of a commercial blend of phytogenic feed additives containing 5% carvacrol, 3% cinnamaldehyde, and 2% capsicum on utilization of dietary energy and performance in broiler chickens. Four experimental diets were offered to the birds from 7 to 21 d of age. These included 2 basal control diets based on either wheat or maize that contained 215 g CP/kg and 12.13 MJ/kg ME and another 2 diets using the basal control diets supplemented with the plant extracts combination at 100 mg/kg diet. Each diet was fed to 16 individually penned birds following randomization. Dietary plant extracts improved feed intake and weight gain (P < 0.05) and slightly (P < 0.1) improved feed efficiency of birds fed the maize-based diet. Supplementary plant extracts did not change dietary ME (P > 0.05) but improved (P < 0.05) dietary NE by reducing the heat increment (P < 0.05) per kilogram feed intake. Feeding phytogenics improved (P < 0.05) total carcass energy retention and the efficiency of dietary ME for carcass energy retention. The number of interactions between type of diet and supplementary phytogenic feed additive suggest that the chemical composition and the energy to protein ratio of the diet may influence the efficiency of phytogenics when fed to chickens. The experiment showed that although supplementary phytogenic additives did not affect dietary ME, they caused a significant improvement in the utilization of dietary energy for carcass energy retention but this did not always relate to growth performance.

Feed form and energy concentration of the diet affect growth performance and digestive tract traits of brown-egg laying pullets from hatching to 17 weeks of age

The influence of feed form and energy concentration of the diet on growth performance and the development of the gastrointestinal tract (GIT) was studied in brown-egg laying pullets. Diets formed a 2 x 5 factorial with 2 feed forms (mash vs. crumbles) and 5 levels of energy differing in 50 kcal AMEn/kg. For the entire study (0 to 17 wk of age) feeding crumbles increased ADFI (52.9 vs. 49.7 g; P < 0.001) and ADG (12.7 vs. 11.6 g; P < 0.001) and improved feed conversion ratio (FCR; 4.18 vs. 4.27; P < 0.001). An increase in the energy content of the diet decreased ADFI linearly (P < 0.001) and improved FCR quadratically (P < 0.01) but energy intake (kcal AMEn/d) was not affected. BW uniformity was higher (P < 0.05) in pullets fed crumbles than in those fed mash but was not affected (P > 0.05) by energy content of the diet. At 5, 10, and 17 wk of age, the relative weight (RW, % BW) of the GIT and the gizzard, and gizzard digesta content were lower (P < 0.05 to P < 0.001) and gizzard pH was higher (P < 0.05 to P < 0.001) in pullets fed crumbles than in pullets fed mash. Energy concentration of the diet did not affect any of the GIT variables studied. In summary, feeding crumbles improved pullet performance and reduced the RW of the GIT and gizzard, and increased gizzard pH at all ages. An increase in the energy content of the diet improved FCR from 0 to 17 wk of age. The use of crumbles and the increase in the AMEn content of the diet might be used adventageously when the objetive is to increase the BW of the pullets. However, crumbles affected the development and weight of the organs of the GIT, which might have negative effects on feed intake and egg production at the beginning of the egg laying cycle.

Parametric and structural self-adaptation of embedded systems using evolvable hardware

Los sistemas empotrados han sido concebidos tradicionalmente como sistemas de procesamiento específicos que realizan una tarea fija durante toda su vida útil. Para cumplir con requisitos estrictos de coste, tamaño y peso, el equipo de diseño debe optimizar su funcionamiento para condiciones muy específicas. Sin embargo, la demanda de mayor versatilidad, un funcionamiento más inteligente y, en definitiva, una mayor capacidad de procesamiento comenzaron a chocar con estas limitaciones, agravado por la incertidumbre asociada a entornos de operación cada vez más dinámicos donde comenzaban a ser desplegados progresivamente. Esto trajo como resultado una necesidad creciente de que los sistemas pudieran responder por si solos a eventos inesperados en tiempo diseño tales como: cambios en las características de los datos de entrada y el entorno del sistema en general; cambios en la propia plataforma de cómputo, por ejemplo debido a fallos o defectos de fabricación; y cambios en las propias especificaciones funcionales causados por unos objetivos del sistema dinámicos y cambiantes. Como consecuencia, la complejidad del sistema aumenta, pero a cambio se habilita progresivamente una capacidad de adaptación autónoma sin intervención humana a lo largo de la vida útil, permitiendo que tomen sus propias decisiones en tiempo de ejecución. Éstos sistemas se conocen, en general, como sistemas auto-adaptativos y tienen, entre otras características, las de auto-configuración, auto-optimización y auto-reparación. Típicamente, la parte soft de un sistema es mayoritariamente la única utilizada para proporcionar algunas capacidades de adaptación a un sistema. Sin embargo, la proporción rendimiento/potencia en dispositivos software como microprocesadores en muchas ocasiones no es adecuada para sistemas empotrados. En este escenario, el aumento resultante en la complejidad de las aplicaciones está siendo abordado parcialmente mediante un aumento en la complejidad de los dispositivos en forma de multi/many-cores; pero desafortunadamente, esto hace que el consumo de potencia también aumente. Además, la mejora en metodologías de diseño no ha sido acorde como para poder utilizar toda la capacidad de cómputo disponible proporcionada por los núcleos. Por todo ello, no se están satisfaciendo adecuadamente las demandas de cómputo que imponen las nuevas aplicaciones. La solución tradicional para mejorar la proporción rendimiento/potencia ha sido el cambio a unas especificaciones hardware, principalmente usando ASICs. Sin embargo, los costes de un ASIC son altamente prohibitivos excepto en algunos casos de producción en masa y además la naturaleza estática de su estructura complica la solución a las necesidades de adaptación. Los avances en tecnologías de fabricación han hecho que la FPGA, una vez lenta y pequeña, usada como glue logic en sistemas mayores, haya crecido hasta convertirse en un dispositivo de cómputo reconfigurable de gran potencia, con una cantidad enorme de recursos lógicos computacionales y cores hardware empotrados de procesamiento de señal y de propósito general. Sus capacidades de reconfiguración han permitido combinar la flexibilidad propia del software con el rendimiento del procesamiento en hardware, lo que tiene la potencialidad de provocar un cambio de paradigma en arquitectura de computadores, pues el hardware no puede ya ser considerado más como estático. El motivo es que como en el caso de las FPGAs basadas en tecnología SRAM, la reconfiguración parcial dinámica (DPR, Dynamic Partial Reconfiguration) es posible. Esto significa que se puede modificar (reconfigurar) un subconjunto de los recursos computacionales en tiempo de ejecución mientras el resto permanecen activos. Además, este proceso de reconfiguración puede ser ejecutado internamente por el propio dispositivo. El avance tecnológico en dispositivos hardware reconfigurables se encuentra recogido bajo el campo conocido como Computación Reconfigurable (RC, Reconfigurable Computing). Uno de los campos de aplicación más exóticos y menos convencionales que ha posibilitado la computación reconfigurable es el conocido como Hardware Evolutivo (EHW, Evolvable Hardware), en el cual se encuentra enmarcada esta tesis. La idea principal del concepto consiste en convertir hardware que es adaptable a través de reconfiguración en una entidad evolutiva sujeta a las fuerzas de un proceso evolutivo inspirado en el de las especies biológicas naturales, que guía la dirección del cambio. Es una aplicación más del campo de la Computación Evolutiva (EC, Evolutionary Computation), que comprende una serie de algoritmos de optimización global conocidos como Algoritmos Evolutivos (EA, Evolutionary Algorithms), y que son considerados como algoritmos universales de resolución de problemas. En analogía al proceso biológico de la evolución, en el hardware evolutivo el sujeto de la evolución es una población de circuitos que intenta adaptarse a su entorno mediante una adecuación progresiva generación tras generación. Los individuos pasan a ser configuraciones de circuitos en forma de bitstreams caracterizados por descripciones de circuitos reconfigurables. Seleccionando aquellos que se comportan mejor, es decir, que tienen una mejor adecuación (o fitness) después de ser evaluados, y usándolos como padres de la siguiente generación, el algoritmo evolutivo crea una nueva población hija usando operadores genéticos como la mutación y la recombinación. Según se van sucediendo generaciones, se espera que la población en conjunto se aproxime a la solución óptima al problema de encontrar una configuración del circuito adecuada que satisfaga las especificaciones. El estado de la tecnología de reconfiguración después de que la familia de FPGAs XC6200 de Xilinx fuera retirada y reemplazada por las familias Virtex a finales de los 90, supuso un gran obstáculo para el avance en hardware evolutivo; formatos de bitstream cerrados (no conocidos públicamente); dependencia de herramientas del fabricante con soporte limitado de DPR; una velocidad de reconfiguración lenta; y el hecho de que modificaciones aleatorias del bitstream pudieran resultar peligrosas para la integridad del dispositivo, son algunas de estas razones. Sin embargo, una propuesta a principios de los años 2000 permitió mantener la investigación en el campo mientras la tecnología de DPR continuaba madurando, el Circuito Virtual Reconfigurable (VRC, Virtual Reconfigurable Circuit). En esencia, un VRC en una FPGA es una capa virtual que actúa como un circuito reconfigurable de aplicación específica sobre la estructura nativa de la FPGA que reduce la complejidad del proceso reconfiguración y aumenta su velocidad (comparada con la reconfiguración nativa). Es un array de nodos computacionales especificados usando descripciones HDL estándar que define recursos reconfigurables ad-hoc: multiplexores de rutado y un conjunto de elementos de procesamiento configurables, cada uno de los cuales tiene implementadas todas las funciones requeridas, que pueden seleccionarse a través de multiplexores tal y como ocurre en una ALU de un microprocesador. Un registro grande actúa como memoria de configuración, por lo que la reconfiguración del VRC es muy rápida ya que tan sólo implica la escritura de este registro, el cual controla las señales de selección del conjunto de multiplexores. Sin embargo, esta capa virtual provoca: un incremento de área debido a la implementación simultánea de cada función en cada nodo del array más los multiplexores y un aumento del retardo debido a los multiplexores, reduciendo la frecuencia de funcionamiento máxima. La naturaleza del hardware evolutivo, capaz de optimizar su propio comportamiento computacional, le convierten en un buen candidato para avanzar en la investigación sobre sistemas auto-adaptativos. Combinar un sustrato de cómputo auto-reconfigurable capaz de ser modificado dinámicamente en tiempo de ejecución con un algoritmo empotrado que proporcione una dirección de cambio, puede ayudar a satisfacer los requisitos de adaptación autónoma de sistemas empotrados basados en FPGA. La propuesta principal de esta tesis está por tanto dirigida a contribuir a la auto-adaptación del hardware de procesamiento de sistemas empotrados basados en FPGA mediante hardware evolutivo. Esto se ha abordado considerando que el comportamiento computacional de un sistema puede ser modificado cambiando cualquiera de sus dos partes constitutivas: una estructura hard subyacente y un conjunto de parámetros soft. De esta distinción, se derivan dos lineas de trabajo. Por un lado, auto-adaptación paramétrica, y por otro auto-adaptación estructural. El objetivo perseguido en el caso de la auto-adaptación paramétrica es la implementación de técnicas de optimización evolutiva complejas en sistemas empotrados con recursos limitados para la adaptación paramétrica online de circuitos de procesamiento de señal. La aplicación seleccionada como prueba de concepto es la optimización para tipos muy específicos de imágenes de los coeficientes de los filtros de transformadas wavelet discretas (DWT, DiscreteWavelet Transform), orientada a la compresión de imágenes. Por tanto, el objetivo requerido de la evolución es una compresión adaptativa y más eficiente comparada con los procedimientos estándar. El principal reto radica en reducir la necesidad de recursos de supercomputación para el proceso de optimización propuesto en trabajos previos, de modo que se adecúe para la ejecución en sistemas empotrados. En cuanto a la auto-adaptación estructural, el objetivo de la tesis es la implementación de circuitos auto-adaptativos en sistemas evolutivos basados en FPGA mediante un uso eficiente de sus capacidades de reconfiguración nativas. En este caso, la prueba de concepto es la evolución de tareas de procesamiento de imagen tales como el filtrado de tipos desconocidos y cambiantes de ruido y la detección de bordes en la imagen. En general, el objetivo es la evolución en tiempo de ejecución de tareas de procesamiento de imagen desconocidas en tiempo de diseño (dentro de un cierto grado de complejidad). En este caso, el objetivo de la propuesta es la incorporación de DPR en EHW para evolucionar la arquitectura de un array sistólico adaptable mediante reconfiguración cuya capacidad de evolución no había sido estudiada previamente. Para conseguir los dos objetivos mencionados, esta tesis propone originalmente una plataforma evolutiva que integra un motor de adaptación (AE, Adaptation Engine), un motor de reconfiguración (RE, Reconfiguration Engine) y un motor computacional (CE, Computing Engine) adaptable. El el caso de adaptación paramétrica, la plataforma propuesta está caracterizada por: • un CE caracterizado por un núcleo de procesamiento hardware de DWT adaptable mediante registros reconfigurables que contienen los coeficientes de los filtros wavelet • un algoritmo evolutivo como AE que busca filtros wavelet candidatos a través de un proceso de optimización paramétrica desarrollado específicamente para sistemas caracterizados por recursos de procesamiento limitados • un nuevo operador de mutación simplificado para el algoritmo evolutivo utilizado, que junto con un mecanismo de evaluación rápida de filtros wavelet candidatos derivado de la literatura actual, asegura la viabilidad de la búsqueda evolutiva asociada a la adaptación de wavelets. En el caso de adaptación estructural, la plataforma propuesta toma la forma de: • un CE basado en una plantilla de array sistólico reconfigurable de 2 dimensiones compuesto de nodos de procesamiento reconfigurables • un algoritmo evolutivo como AE que busca configuraciones candidatas del array usando un conjunto de funcionalidades de procesamiento para los nodos disponible en una biblioteca accesible en tiempo de ejecución • un RE hardware que explota la capacidad de reconfiguración nativa de las FPGAs haciendo un uso eficiente de los recursos reconfigurables del dispositivo para cambiar el comportamiento del CE en tiempo de ejecución • una biblioteca de elementos de procesamiento reconfigurables caracterizada por bitstreams parciales independientes de la posición, usados como el conjunto de configuraciones disponibles para los nodos de procesamiento del array Las contribuciones principales de esta tesis se pueden resumir en la siguiente lista: • Una plataforma evolutiva basada en FPGA para la auto-adaptación paramétrica y estructural de sistemas empotrados compuesta por un motor computacional (CE), un motor de adaptación (AE) evolutivo y un motor de reconfiguración (RE). Esta plataforma se ha desarrollado y particularizado para los casos de auto-adaptación paramétrica y estructural. • En cuanto a la auto-adaptación paramétrica, las contribuciones principales son: – Un motor computacional adaptable mediante registros que permite la adaptación paramétrica de los coeficientes de una implementación hardware adaptativa de un núcleo de DWT. – Un motor de adaptación basado en un algoritmo evolutivo desarrollado específicamente para optimización numérica, aplicada a los coeficientes de filtros wavelet en sistemas empotrados con recursos limitados. – Un núcleo IP de DWT auto-adaptativo en tiempo de ejecución para sistemas empotrados que permite la optimización online del rendimiento de la transformada para compresión de imágenes en entornos específicos de despliegue, caracterizados por tipos diferentes de señal de entrada. – Un modelo software y una implementación hardware de una herramienta para la construcción evolutiva automática de transformadas wavelet específicas. • Por último, en cuanto a la auto-adaptación estructural, las contribuciones principales son: – Un motor computacional adaptable mediante reconfiguración nativa de FPGAs caracterizado por una plantilla de array sistólico en dos dimensiones de nodos de procesamiento reconfigurables. Es posible mapear diferentes tareas de cómputo en el array usando una biblioteca de elementos sencillos de procesamiento reconfigurables. – Definición de una biblioteca de elementos de procesamiento apropiada para la síntesis autónoma en tiempo de ejecución de diferentes tareas de procesamiento de imagen. – Incorporación eficiente de la reconfiguración parcial dinámica (DPR) en sistemas de hardware evolutivo, superando los principales inconvenientes de propuestas previas como los circuitos reconfigurables virtuales (VRCs). En este trabajo también se comparan originalmente los detalles de implementación de ambas propuestas. – Una plataforma tolerante a fallos, auto-curativa, que permite la recuperación funcional online en entornos peligrosos. La plataforma ha sido caracterizada desde una perspectiva de tolerancia a fallos: se proponen modelos de fallo a nivel de CLB y de elemento de procesamiento, y usando el motor de reconfiguración, se hace un análisis sistemático de fallos para un fallo en cada elemento de procesamiento y para dos fallos acumulados. – Una plataforma con calidad de filtrado dinámica que permite la adaptación online a tipos de ruido diferentes y diferentes comportamientos computacionales teniendo en cuenta los recursos de procesamiento disponibles. Por un lado, se evolucionan filtros con comportamientos no destructivos, que permiten esquemas de filtrado en cascada escalables; y por otro, también se evolucionan filtros escalables teniendo en cuenta requisitos computacionales de filtrado cambiantes dinámicamente. Este documento está organizado en cuatro partes y nueve capítulos. La primera parte contiene el capítulo 1, una introducción y motivación sobre este trabajo de tesis. A continuación, el marco de referencia en el que se enmarca esta tesis se analiza en la segunda parte: el capítulo 2 contiene una introducción a los conceptos de auto-adaptación y computación autonómica (autonomic computing) como un campo de investigación más general que el muy específico de este trabajo; el capítulo 3 introduce la computación evolutiva como la técnica para dirigir la adaptación; el capítulo 4 analiza las plataformas de computación reconfigurables como la tecnología para albergar hardware auto-adaptativo; y finalmente, el capítulo 5 define, clasifica y hace un sondeo del campo del hardware evolutivo. Seguidamente, la tercera parte de este trabajo contiene la propuesta, desarrollo y resultados obtenidos: mientras que el capítulo 6 contiene una declaración de los objetivos de la tesis y la descripción de la propuesta en su conjunto, los capítulos 7 y 8 abordan la auto-adaptación paramétrica y estructural, respectivamente. Finalmente, el capítulo 9 de la parte 4 concluye el trabajo y describe caminos de investigación futuros. ABSTRACT Embedded systems have traditionally been conceived to be specific-purpose computers with one, fixed computational task for their whole lifetime. Stringent requirements in terms of cost, size and weight forced designers to highly optimise their operation for very specific conditions. However, demands for versatility, more intelligent behaviour and, in summary, an increased computing capability began to clash with these limitations, intensified by the uncertainty associated to the more dynamic operating environments where they were progressively being deployed. This brought as a result an increasing need for systems to respond by themselves to unexpected events at design time, such as: changes in input data characteristics and system environment in general; changes in the computing platform itself, e.g., due to faults and fabrication defects; and changes in functional specifications caused by dynamically changing system objectives. As a consequence, systems complexity is increasing, but in turn, autonomous lifetime adaptation without human intervention is being progressively enabled, allowing them to take their own decisions at run-time. This type of systems is known, in general, as selfadaptive, and are able, among others, of self-configuration, self-optimisation and self-repair. Traditionally, the soft part of a system has mostly been so far the only place to provide systems with some degree of adaptation capabilities. However, the performance to power ratios of software driven devices like microprocessors are not adequate for embedded systems in many situations. In this scenario, the resulting rise in applications complexity is being partly addressed by rising devices complexity in the form of multi and many core devices; but sadly, this keeps on increasing power consumption. Besides, design methodologies have not been improved accordingly to completely leverage the available computational power from all these cores. Altogether, these factors make that the computing demands new applications pose are not being wholly satisfied. The traditional solution to improve performance to power ratios has been the switch to hardware driven specifications, mainly using ASICs. However, their costs are highly prohibitive except for some mass production cases and besidesthe static nature of its structure complicates the solution to the adaptation needs. The advancements in fabrication technologies have made that the once slow, small FPGA used as glue logic in bigger systems, had grown to be a very powerful, reconfigurable computing device with a vast amount of computational logic resources and embedded, hardened signal and general purpose processing cores. Its reconfiguration capabilities have enabled software-like flexibility to be combined with hardware-like computing performance, which has the potential to cause a paradigm shift in computer architecture since hardware cannot be considered as static anymore. This is so, since, as is the case with SRAMbased FPGAs, Dynamic Partial Reconfiguration (DPR) is possible. This means that subsets of the FPGA computational resources can now be changed (reconfigured) at run-time while the rest remains active. Besides, this reconfiguration process can be triggered internally by the device itself. This technological boost in reconfigurable hardware devices is actually covered under the field known as Reconfigurable Computing. One of the most exotic fields of application that Reconfigurable Computing has enabled is the known as Evolvable Hardware (EHW), in which this dissertation is framed. The main idea behind the concept is turning hardware that is adaptable through reconfiguration into an evolvable entity subject to the forces of an evolutionary process, inspired by that of natural, biological species, that guides the direction of change. It is yet another application of the field of Evolutionary Computation (EC), which comprises a set of global optimisation algorithms known as Evolutionary Algorithms (EAs), considered as universal problem solvers. In analogy to the biological process of evolution, in EHW the subject of evolution is a population of circuits that tries to get adapted to its surrounding environment by progressively getting better fitted to it generation after generation. Individuals become circuit configurations representing bitstreams that feature reconfigurable circuit descriptions. By selecting those that behave better, i.e., with a higher fitness value after being evaluated, and using them as parents of the following generation, the EA creates a new offspring population by using so called genetic operators like mutation and recombination. As generations succeed one another, the whole population is expected to approach to the optimum solution to the problem of finding an adequate circuit configuration that fulfils system objectives. The state of reconfiguration technology after Xilinx XC6200 FPGA family was discontinued and replaced by Virtex families in the late 90s, was a major obstacle for advancements in EHW; closed (non publicly known) bitstream formats; dependence on manufacturer tools with highly limiting support of DPR; slow speed of reconfiguration; and random bitstream modifications being potentially hazardous for device integrity, are some of these reasons. However, a proposal in the first 2000s allowed to keep investigating in this field while DPR technology kept maturing, the Virtual Reconfigurable Circuit (VRC). In essence, a VRC in an FPGA is a virtual layer acting as an application specific reconfigurable circuit on top of an FPGA fabric that reduces the complexity of the reconfiguration process and increases its speed (compared to native reconfiguration). It is an array of computational nodes specified using standard HDL descriptions that define ad-hoc reconfigurable resources; routing multiplexers and a set of configurable processing elements, each one containing all the required functions, which are selectable through functionality multiplexers as in microprocessor ALUs. A large register acts as configuration memory, so VRC reconfiguration is very fast given it only involves writing this register, which drives the selection signals of the set of multiplexers. However, large overheads are introduced by this virtual layer; an area overhead due to the simultaneous implementation of every function in every node of the array plus the multiplexers, and a delay overhead due to the multiplexers, which also reduces maximum frequency of operation. The very nature of Evolvable Hardware, able to optimise its own computational behaviour, makes it a good candidate to advance research in self-adaptive systems. Combining a selfreconfigurable computing substrate able to be dynamically changed at run-time with an embedded algorithm that provides a direction for change, can help fulfilling requirements for autonomous lifetime adaptation of FPGA-based embedded systems. The main proposal of this thesis is hence directed to contribute to autonomous self-adaptation of the underlying computational hardware of FPGA-based embedded systems by means of Evolvable Hardware. This is tackled by considering that the computational behaviour of a system can be modified by changing any of its two constituent parts: an underlying hard structure and a set of soft parameters. Two main lines of work derive from this distinction. On one side, parametric self-adaptation and, on the other side, structural self-adaptation. The goal pursued in the case of parametric self-adaptation is the implementation of complex evolutionary optimisation techniques in resource constrained embedded systems for online parameter adaptation of signal processing circuits. The application selected as proof of concept is the optimisation of Discrete Wavelet Transforms (DWT) filters coefficients for very specific types of images, oriented to image compression. Hence, adaptive and improved compression efficiency, as compared to standard techniques, is the required goal of evolution. The main quest lies in reducing the supercomputing resources reported in previous works for the optimisation process in order to make it suitable for embedded systems. Regarding structural self-adaptation, the thesis goal is the implementation of self-adaptive circuits in FPGA-based evolvable systems through an efficient use of native reconfiguration capabilities. In this case, evolution of image processing tasks such as filtering of unknown and changing types of noise and edge detection are the selected proofs of concept. In general, evolving unknown image processing behaviours (within a certain complexity range) at design time is the required goal. In this case, the mission of the proposal is the incorporation of DPR in EHW to evolve a systolic array architecture adaptable through reconfiguration whose evolvability had not been previously checked. In order to achieve the two stated goals, this thesis originally proposes an evolvable platform that integrates an Adaptation Engine (AE), a Reconfiguration Engine (RE) and an adaptable Computing Engine (CE). In the case of parametric adaptation, the proposed platform is characterised by: • a CE featuring a DWT hardware processing core adaptable through reconfigurable registers that holds wavelet filters coefficients • an evolutionary algorithm as AE that searches for candidate wavelet filters through a parametric optimisation process specifically developed for systems featured by scarce computing resources • a new, simplified mutation operator for the selected EA, that together with a fast evaluation mechanism of candidate wavelet filters derived from existing literature, assures the feasibility of the evolutionary search involved in wavelets adaptation In the case of structural adaptation, the platform proposal takes the form of: • a CE based on a reconfigurable 2D systolic array template composed of reconfigurable processing nodes • an evolutionary algorithm as AE that searches for candidate configurations of the array using a set of computational functionalities for the nodes available in a run time accessible library • a hardware RE that exploits native DPR capabilities of FPGAs and makes an efficient use of the available reconfigurable resources of the device to change the behaviour of the CE at run time • a library of reconfigurable processing elements featured by position-independent partial bitstreams used as the set of available configurations for the processing nodes of the array Main contributions of this thesis can be summarised in the following list. • An FPGA-based evolvable platform for parametric and structural self-adaptation of embedded systems composed of a Computing Engine, an evolutionary Adaptation Engine and a Reconfiguration Engine. This platform is further developed and tailored for both parametric and structural self-adaptation. • Regarding parametric self-adaptation, main contributions are: – A CE adaptable through reconfigurable registers that enables parametric adaptation of the coefficients of an adaptive hardware implementation of a DWT core. – An AE based on an Evolutionary Algorithm specifically developed for numerical optimisation applied to wavelet filter coefficients in resource constrained embedded systems. – A run-time self-adaptive DWT IP core for embedded systems that allows for online optimisation of transform performance for image compression for specific deployment environments characterised by different types of input signals. – A software model and hardware implementation of a tool for the automatic, evolutionary construction of custom wavelet transforms. • Lastly, regarding structural self-adaptation, main contributions are: – A CE adaptable through native FPGA fabric reconfiguration featured by a two dimensional systolic array template of reconfigurable processing nodes. Different processing behaviours can be automatically mapped in the array by using a library of simple reconfigurable processing elements. – Definition of a library of such processing elements suited for autonomous runtime synthesis of different image processing tasks. – Efficient incorporation of DPR in EHW systems, overcoming main drawbacks from the previous approach of virtual reconfigurable circuits. Implementation details for both approaches are also originally compared in this work. – A fault tolerant, self-healing platform that enables online functional recovery in hazardous environments. The platform has been characterised from a fault tolerance perspective: fault models at FPGA CLB level and processing elements level are proposed, and using the RE, a systematic fault analysis for one fault in every processing element and for two accumulated faults is done. – A dynamic filtering quality platform that permits on-line adaptation to different types of noise and different computing behaviours considering the available computing resources. On one side, non-destructive filters are evolved, enabling scalable cascaded filtering schemes; and on the other, size-scalable filters are also evolved considering dynamically changing computational filtering requirements. This dissertation is organized in four parts and nine chapters. First part contains chapter 1, the introduction to and motivation of this PhD work. Following, the reference framework in which this dissertation is framed is analysed in the second part: chapter 2 features an introduction to the notions of self-adaptation and autonomic computing as a more general research field to the very specific one of this work; chapter 3 introduces evolutionary computation as the technique to drive adaptation; chapter 4 analyses platforms for reconfigurable computing as the technology to hold self-adaptive hardware; and finally chapter 5 defines, classifies and surveys the field of Evolvable Hardware. Third part of the work follows, which contains the proposal, development and results obtained: while chapter 6 contains an statement of the thesis goals and the description of the proposal as a whole, chapters 7 and 8 address parametric and structural self-adaptation, respectively. Finally, chapter 9 in part 4 concludes the work and describes future research paths.

Obesity and mild hyperinsulinemia found in neuropeptide Y-Y1 receptor-deficient mice

To elucidate the role of neuropeptide Y (NPY)-Y1 receptor (Y1-R) in food intake, energy expenditure, and other possible functions, we have generated Y1-R-deficient mice (Y1-R−/−) by gene targeting. Contrary to our hypothesis that the lack of NPY signaling via Y1-R would result in impaired feeding and weight loss, Y1-R−/− mice showed a moderate obesity and mild hyperinsulinemia without hyperphagia. Although there was some variation between males and females, typical characteristics of Y1-R−/− mice include: greater body weight (females more than males), an increase in the weight of white adipose tissue (WAT) (approximately 4-fold in females), an elevated basal level of plasma insulin (approximately 2-fold), impaired insulin secretion in response to glucose administration, and a significant changes in mitochondrial uncoupling protein (UCP) gene expression (up-regulation of UCP1 in brown adipose tissue and down-regulation of UCP2 in WAT). These results suggest either that the Y1-R in the hypothalamus is not a key molecule in the leptin/NPY pathway, which controls feeding behavior, or that its deficiency is compensated by other receptors, such as NPY-Y5 receptor. We believe that the mild obesity found in Y1-R−/− mice (especially females) was caused by the impaired control of insulin secretion and/or low energy expenditure, including the lowered expression of UCP2 in WAT. This model will be useful for studying the mechanism of mild obesity and abnormal insulin metabolism in noninsulin-dependent diabetes mellitus.

PGC-1 alfa como regulador inflamatório na esteato-hepatite não-alcoólica

A doença hepática gordurosa não-alcoólica (NAFLD, do inglês) é a manifestação clínica hepática da síndrome metabólica, cuja incidência aumenta consideravelmente em todo o mundo. A NAFLD pode progredir para um estado de esteatohepatite não-alcoólica (NASH, do inglês), caracterizado por inflamação hepatocelular, com ou sem fibrose. Dados na literatura mostram que o coativador-1 alfa do receptor ativado por proliferadores de peroxissoma gama (PGC-1alfa), além de estar envolvido em diversos processos metabólicos, representa uma estratégia terapêutica promissora na modulação da inflamação. Neste projeto investigamos as alterações inflamatórias no fígado induzida por dieta hiperlipídica e o papel do PGC-1alfa nesse processo. Camundongos C57black/6 receberam dieta hiperlipídica contendo 30% de gordura por 10 semanas. O peso dos animais foi avaliado semanalmente. Após a eutanásia, o tecido adiposo intra-abdominal (retroperitoneal e periepididimal) foi coletado e pesado. Analisamos o perfil glicêmico e lipídico sérico e expressão de genes envolvidos no metabolismo glicêmico e lipídico. Avaliou-se também o aspecto histológico e a inflamação do tecido hepático por quantificação das citocinas IL-6, TNF-alfa e IL-1beta. A dieta rica em gordura conduziu a um aumento dos depósitos de gordura intra-abdominal, hiperglicemia e hiperlipidemia. Os animais também apresentavam esteatohepatite, com aumento de citocinas pró-inflamatórias e diminuição na expressão de PGC-1alfa no tecido hepático. O envolvimento do PGC-1alfa na produção de mediadores inflamatórios por hepatócitos foi avaliado em células HepG2 utilizando RNA de interferência (RNAi). O knockdown da expressão de PGC-1alfa causou aumento na expressão e liberação de IL-6 em hepatócitos via aumento na fosforilação de IkBalfa e consequente ativação do NFkB. Portanto, nossos dados mostram que o PGC-1alfa inibe a produção de mediadores inflamatórios (IL-6) em hepatócitos, e fornecem novas evidências das conexões existentes entre as vias metabólicas e imunes

Distortion of self-image: risk factor for obesity in children and teenagers

Introduction: Self-image is important in the behaviour and lifestyle of children and adolescents. Analysing the self-image they have and the factors that might influence their distortion, can be used to prevent problems of obesity and anorexia. The main objective of present publication was to analyse the risk factors that may contribute to self-image distortion. Material and Methods: A descriptive survey study was conducted among 659 children and adolescents in two social classes (low and medium-high), measuring height and weight, calculating BMI percentile for age and gender. Body image and self-perception were registered. Results: The percentage of overweight-obesity is higher in scholars (41.8% boys, 28.7% girls) than in adolescents (30.1% and 22.2% respectively), with no difference between socioeconomic classes. The multinomial logistic regression analysis gives a risk of believing thinner higher (p=0.000) among boys OR=2.9(95%CI:1.43-3.37), school (p=0.000) OR=2.42(95%CI:1.56-3.76) and much lower (p=0.000) between normally nourished OR=0.08(95%CI:0.05-0.13), with no differences according to socioeconomic status. The risk of believing fatter is lower (p=0.000) between boys OR=0.28(95%CI:0.14-0.57), school(p=0.072) OR=0.54(95%CI:0.27-1.6), and much higher among underweight (p=0.000) OR=9x108(95% CI:4x108-19x108). Conclusions: Are risk factors of believing thinner: males, being in a group of schoolchildren and overweight-obesity. Conversely, are risk factors of believing fatter: females, teen and above all, be thin.