Electron and Phonon Thermal Waves in Semiconductors: an Application to Photothermal Effects

The electron and phonon temperature distribution function are calculated in semiconductors. We solved the coupled one-dimensional heat-diffussion equations in the linear approximation in which the physical parameters on the sample are independent of the temperature. We also consider the heat flux at the surface of the semiconductor as a boundary condition for each electron and phonon systems instead of using a fixed temperature. From this, we obtain an expression for electron and phonon temperature respectively. The characterization of the thermal waves properties is duscussed and some practical procedures for this purpose provide us information about the electron and phonon thermal parameters.Comment: 12 pages, amstex and amssymb macro package (LaTeX2e edition

Metodologia para la evaluacion de sistemas de refrigeracion industrial

Este articulo muestra una metodología que puede ser usada en diferentes sistemas de refrigeración. En este trabajo fue aplicada en un combinado cárnico de la Republica de Cuba con resultados satisfactorios, es confiable y precisa

Metodologia para la evaluacion de sistemas de refrigeracion industrial

Este articulo muestra una metodología que puede ser usada en diferentes sistemas de refrigeración. En este trabajo fue aplicada en un combinado cárnico de la Republica de Cuba con resultados satisfactorios, es confiable y precisa

Thermal Diffusion of a Two Layer System

In this paper thermal conductivity and thermal diffusivity of a two layer system is examined from the theoretical point of view. We use the one dimensional heat diffusion equation with the appropriate solution in each layer and boundary conditions at the interfaces to calculate the heat transport in this bounded system. We also consider the heat flux at the surface of the samle as boundary condition instead of using a fixed tempertaure. From this, we obtain an expression for the efective thermal diffusivity of the composite sample in terms of the thermal diffusivity of its constituent materials whithout any approximations.Comment: 16 pages, 1 figure, RevTeX v. 3.0 macro packag

Levels of insulin and HOMA-IR in adolescents in Saltillo, Coahuila, Mexico

An alarming rise of obesity in adolescents has been observed, placing them at risk of developing resistance to insulin (IR) and its adverse metabolic consequences such as diabetes mellitus type 2 (DM2), metabolic syndrome and cardiovascular disease. Objective: To know the prevalence of obesity, and the levels of glucose, insulin and HOMA-IR and its association with the BMIz, waist circumference and the pubertal stage in a random sample of adolescents. Materials and methods: 292 adolescents between 12 and 15 years (152 female and 140 male), whose anthropometric measurements (weight, height and waist circumference) were taken, body mass index calculated and Z-score determined. Blood glucose and insulin levels were evaluated from a sample of blood and their HOMA-IR was determined. Results: The results showed that 32.5% were obese, 22.3% were overweight and 23.6% showed adolescent central obesity. Glucose levels (p = 0.016), insulin (p = 0.0001) and HOMA-IR (p = 0.0001) showed significant differences in the group with obesity. Values of the three parameters were increased with the stage of puberty. We found significant differences in the levels of glucose (p = 0.0388), insulin (p = 0.0005) and HOMA-IR (p = 0.0001) between the prepubertal and postpubertal stages

A Phase I/II Clinical Trial to evaluate the efficacy of baricitinib to prevent respiratory insufficiency progression in onco-hematological patients affected with COVID19: a structured summary of a study protocol for a randomised controlled trial

Objectives: Baricitinib is supposed to have a double effect on SARS-CoV2 infection. Firstly, it reduces the inflammatory response through the inhibition of the Januse-Kinase signalling transducer and activator of transcription (JAK-STAT) pathway. Moreover, it reduces the receptor mediated viral endocytosis by AP2-associated protein kinase 1 (AAK1) inhibition. We propose the use of baricinitib to prevent the progression of the respiratory insufficiency in SARS-CoV2 pneumonia in onco-haematological patients. In this phase Ib/II study, the primary objective in the safety cohort is to describe the incidence of severe adverse events associated with baricitinib administration. The primary objective of the randomized phase (baricitinib cohort versus standard of care cohort) is to evaluate the number of patients who did not require mechanical oxygen support since start of therapy until day +14 or discharge (whichever it comes first). The secondary objectives of the study (only randomized phase of the study) are represented by the comparison between the two arms of the study in terms of mortality and toxicity at day+30. Moreover, a description of the immunological related changes between the two arms of the study will be reported. Trial design: The trial is a phase I/II study with a safety run-in cohort (phase 1) followed by an open label phase II randomized controlled trial with an experimental arm compared to a standard of care arm

Comparative study on the clinical-nutritional status of obese postmenopausal women on a weight loss programme based on prepared dishes

Comparative Study; English Abstract; Journal Article;INTRODUCTION Few studies have evaluated the efficacy and reliability of weight loss-focussed prepared food dishes in obese post-menopausal women. OBJECTIVE To compare the efficacy of a weight loss programme based on a balanced hypocaloric diet using prepared dishes* with that of a similar programme based on standard commercially available foods and with a non-intervened control group. A further aim was to evaluate the subjectivity of participants in the preparation of the diet-adjusted dishes based on usually consumed products. SUBJECTS Obese post-menopausal women aged between 55 and 65 years. DESIGN Controlled longitudinal interventional study. METHOD The sample of 75 female volunteers were divided into three groups of 25 women: a control group, who continued to consume their usual non-dietary adjusted meals (CG), an intervened group, treated with a diet adjusted to their individual requirements and based on standard commercially available food (SG), and another intervened group, treated with a similarly adjusted diet but based on prepared dishes (PG). Data were gathered on anthropometric variables, consumption habits and physical activity levels, and clinical-nutritional controls were conducted at the start and every two weeks to the end of the 8-week study in order to evaluate biochemical changes. RESULTS The weight loss was slightly higher in the prepared-dishes group (PG) than in the standard food diet group (SG), but the difference was not statistically significant, whereas it was considerably higher in both groups than in the non-dietary adjusted control group (CG) and this difference was highly significant (losses of 7.60 kg in PG and 7.01 kg in SG versus 2.10 kg in CG (p < 0.01). However, the PG showed a significantly higher (p < 0.01) loss of fatty mass and abdominal circumference versus the SG women. CONCLUSION More weight was lost by the two groups treated with a diet based on prepared dishes or usual food items in comparison to untreated controls, but the diet based on prepared dishes obtained more reliable and higher quality outcomes, achieving a positive change at fatty compartment level and in the abdominal circumference.El presente proyecto ha sido financiado por la empresa Deliline® S. A.YesIntroducción: Son escasos los estudios que hayan evaluado la eficacia y la fiabilidad de los platos de comidas preparadas* enfocadas a la pérdida de peso en la mujer posmenopáusica obesa. Objetivo: Evaluar la eficiencia de un programa de pérdida de peso basado en una ingesta hipocalórica equilibrada, a partir de platos preparados* comparando con otra basada en alimentos de consumo habitual en el mercado y con un grupo control no intervenido. En el presente estudio se pretende, además, valorar la subjetividad de la participante a la hora de preparar los platos ajustados a la dieta de restricción basada en productos de consumo habitual. Sujetos de estudio: mujeres posmenopáusicas obesas, con edad comprendida entre 55-65 años. Diseño del estudio: Estudio longitudinal de intervención y controlado. Metodología: La muestra de 75 mujeres voluntarias se divide en tres grupos de 25 mujeres; uno con alimentación habitual, sin dieta ajustada (GC), otro intervenido mediante tratamiento con una dieta ajustada a los requerimientos individuales, pero con productos de consumo habitual en mercado (GE) y un tercero intervenido con dieta ajustada del mismo modo al anterior, pero con platos preparados (GD). Se registraron datos antropométricos, hábitos de consumo y nivel de actividad física. También se realizaron controles clínico-nutricionales para evaluar cambios bioquímicos al inicio del estudio, cada 2 semanas y al final del estudio, durante 8 semanas. Resultados: El grupo basado en platos preparados GD muestra resultados de pérdida de peso ligeramente mayores, aunque no estadísticamente significativos, al grupo de dieta estándar GE, mostrando, sin embargo, ambos, descensos muy significativos respecto al grupo no ajustado GC (con una pérdida de 7,60 kg en GD, 7,01 kg en el grupo GE y 2,10 kg en GC). Sin embargo, éste grupo de mujeres alimentadas con dieta hipocalórica basada en platos preparados GD, presenta (p < 0,01) una mayor pérdida significativa, tanto de masa grasa como de perímetro abdominal. Conclusión: Las mujeres tratadas con dieta basada en platos preparados GD y las tratadas con dieta ajustada habitual GE presentan una mayor pérdida de peso, pero el grupo GD mostró unos resultados más fiables y de calidad, dado el cambio positivo encontrado a nivel de compartimento graso y en el perímetro abdominal de las participantes del grupo objeto del estudio

Influence of chronic food deprivation on structure-function relationship of juvenile rat fast muscles

In the present study, we analyze the influence of chronic undernutrition on protein expression, muscle fiber type composition, and fatigue resistance of the fast extensor digitorum longus (EDL) muscle of male juvenile rats (45 ± 3 days of life; n = 25 and 31 rats for control and undernourished groups, respectively). Using 2D gel electrophoresis and mass spectrometry, we identified in undernourished muscles 12 proteins up-regulated (8 proteins of the electron transport chain and the glycolytic pathway, 2 cross-bridge proteins, chaperone and signaling proteins that are related to the stress response). In contrast, one down-regulated protein related to the fast muscle contractile system and two other proteins with no changes in expression were used as charge controls. By means of COX and alkaline ATPase histochemical techniques and low-frequency fatigue protocols we determined that undernourished muscles showed a larger proportion (15 % increase) of Type IIa/IId fibers (oxidative- glycolytic) at the expense of Type IIb (glycolytic) fibers (15.5 % decrease) and increased fatigue resistance (55.3 %). In addition, all fiber types showed a significant reduction in their cross-sectional area (slow: 64.4 %; intermediate: 63.9 % and fast: 61.2 %). These results indicate that undernourished EDL muscles exhibit an increased expression of energy metabolic and myofibrillar proteins which are associated with the predominance of oxidative and Type IIa/IId fibers and to a higher resistance to fatigue. We propose that such alterations may act as protective and/or adaptive mechanisms that counterbalance the effect of chronic undernourishment. © 2013 Springer Science+Business Media Dordrecht

The nature of the high Galactic latitude O-star HD93521: new results from X-ray and optical spectroscopy

Owing to its unusual location and its isolation, the nature of the high Galactic latitude O9.5Vp object HD93521 is still uncertain. We have collected X-ray and optical observations to characterize the star and its surroundings. X-ray images and spectra are analyzed to search for traces of a recent star formation event around HD93521 and to search for the signature of a possible compact companion. Optical echelle spectra are analysed with plane-parallel model atmosphere codes, assuming either a spherical star or a gravity darkened rotationally flattened star, to infer the effective temperature and surface gravity, and to derive the He, C, N and O abundances of HD93521. The X-ray images reveal no traces of a population of young low-mass stars coeval with HD93521. The X-ray spectrum of HD93521 is consistent with a normal late O-type star although with subsolar metallicity. No trace of a compact companion is found in the X-ray data. In the optical spectrum, He and N are found to be overabundant, in line with the effect of rotational mixing in this very fast rotator, whilst C and O are subsolar. A critical comparison with the properties of subdwarf OB stars, indicates that, despite some apparent similarities, HD93521 does not belong to this category. Despite some ambiguities on the runaway status of the star, the most likely explanation is that HD93521 is a Population I massive O-type star that was ejected from the Galactic plane either through dynamical interactions or a result of a supernova event in a binary system.Comment: Accepted for publication in Astronomy & Astrophysic

The energy of waves in the photosphere and lower chromosphere: III. Inversion setup for Ca II H spectra in local thermal equilibrium

The Ca II H line is one of the strongest lines in the solar spectrum and provides continuous information on the solar atmosphere from the photosphere to the lower chromosphere. We describe an inversion approach that reproduces observed Ca II H spectra assuming LTE. We developed an inversion strategy based on the SIR code. The approach uses a two-step procedure with an archive of pre-calculated spectra to fit the line core and a subsequent iterative modification to improve the fit in the line wing. Simultaneous spectra in the 630nm range can optionally be used to fix the continuum temperature. The method retrieves 1D temperature stratifications neglecting lateral radiative transport. LOS velocities are included by an empirical approach. An archive of about 300.000 pre-calculated spectra is more than sufficient to reproduce the line core of observed Ca II H spectra both in quiet Sun and in active regions. The final thermodynamical stratifications match observed and best-fit spectra to a level of about 0.5 (1) % of Ic in the line wing (core). Inversion schemes based on pre-calculated spectra allow one a reliable and relatively fast retrieval of solar properties from observed chromospheric spectra. The approach can be easily extended to an 1D NLTE case by a simple exchange of the pre-calculated archive spectra.Comment: 15 pages, 15 figures, accepted for publication in A&A. The animation will only be provided in the A&A online sectio