High-frequency collective excitations in molten and glassy Te studied by inelastic neutron scattering

7 págs.; 5 figs.; 1 tab. ; PACS number s : 61.25.Mv, 61.43.Er, 61.20.Lc, 61.12. qhttp://dx.doi.org/10.1103/PhysRevB.73.094201The spectra of collective excitations of liquid and glassy tellurium have been studied by means of inelastic neutron scattering. Here we report on the dynamics of liquid Te as measured at two different temperatures, just above melting (Tm =723 K) and at ∼1000 K as well as the glass that is studied at room temperature. Estimates for the velocity of propagating excitations for both temperatures have been obtained from the experimental data, and a contrasting behavior is found with respect to anomalies shown by the adiabatic sound velocity measured by ultrasound methods. The origin of such differences is finally discussed. © 2006 The American Physical Society.This work was supported in part by Grant No. MAT2002- 04178-C04 SpainPeer Reviewe

Eficacia de un programa para el tratamiento del sobrepeso y la obesidad no mórbida en atención primaria y su influencia en la modificación de estilos de vida

Introducción y Objetivos: la modificación de conductas no saludables es fundamental para tratar la obesidad. El objetivo de este estudio fue evaluar los efectos de un programa basado en dieta, ejercicio y apoyo psicológico en la modificación conductual de pacientes con sobrepeso y obesidad tratados en Atención Primaria. Métodos: 60 pacientes con sobrepeso grado II y obesidad grado I-II fueron incluidos en este ensayo piloto. Edad entre 18-50 años. Los pacientes recibieron un programa que combinaba educación nutricional, actividad física y apoyo psicológico. Formato grupal, periodicidad quincenal. Los principales resultados medidos al inicio y 6 meses fueron parámetros antropométricos (índice de masa corporal, porcentaje de masa grasa, perímetro cintura) y de estilos de vida usando el Cuestionario para la valoración de hábitos de vida relacionados con el sobrepeso y la obesidad. Consta de 5 dimensiones: contenido calórico de la dieta (CC), alimentación saludable (AS), ejercicio físico (EF), comer por bienestar psicológico (BP) y consumo de alcohol (CA). La mayor puntuación indica mejores hábitos para CC, AS y EF y peores para BP y CA. Resultados: al final de la intervención mejoraron las escalas CC (2,60± 0,5 vs 3,49± 0,7, p<0,001), EF (2,19± 0,9 vs 3,17± 1,0, p<0,001) y AS (3,04± 0,4 vs 3,43± 0,4, p<0,05) del cuestionario; CA (3,98± 0,7 vs. 4,25± 0,7, p<0,05) y BP (2,82± 1,0 vs. 3,34± 0,7, p<0,001) empeoraron. Conclusión: el programa basado en moderada restricción de la dieta, aumento de actividad física y apoyo psicológico puede mejorar parámetros antropométricos y estilos de vida en pacientes obesos tratados en un centro de Atención PrimariaBackground: Lifestyle intervention is fundamental for obesity treatment. The aim of this study was to evaluate the effects of a program focused on diet, exercise and psychological support on Lifestyle Modification in overweight and obese patients treated in Primary Health Care setting. Methods: 60 patients with grade II overweight and non-morbid grade I-II obesity were included in this pilot clinical trial. Ages ranged from18 to 50 years. They were provided with a program combining nutritional education, physical activity and psychological support. Subjects attended group sessions every 2 weeks. The main outcome measures at baseline and 6 months were body composition parameters (BMI, body fat percentage, waist circumference) and lifestyle intervention using the Questionnaire for the assessment of overweight and obesity related lifestyles at baseline and six months. This questionnaire yields an five dimensions: diet caloric intake (CC), healthy eating (AS), physical activity (EF), searching for psychological well-being eating (BP) and alcohol intake (CA). The higher score indicates better lifestyles for CC, AS, EF and worse for BP y CA. Results: At the end of the intervention the program achieved improvements in Questionnaire related lifestyles subscales: CC (2,60± 0,5 vs. 3,49± 0,7, p<0,001), EF (2,19± 0,9 vs. 3,17± 1,0, p<0,001) and AS (3,04± 0,4 vs. 3,43± 0,4, p<0,05); CA (3,98± 0,7 vs. 4,25± 0,7, p<0,05) and BP (2,82± 1,0 vs. 3,34± 0,7, p<0,001) has got worse. Conclusion: The Program focused on balanced and moderate energy-restricted diets, increased physical activity and psychological support may improve the anthropometric parameters and the Lifestyle intervention in obese patients treated in a primary healthcare center.Este proyecto ha sido becado por el Ministerio de Ciencia e Innovación, a través del Instituto de Salud Carlos III y la Subdirección General de Evaluación y Fomento de la Investigación, en el marco del «Subprograma de Proyectos de Investigación de Evaluación de Tecnologías Sanitarias e Investigación en servicios de salud». Convocatoria 2008 de ayudas de la Acción Estratégica en Salud, en el marco del Plan Nacional de I+D+I 2008-2011 (PI08/90357). Y por la Fundación MAPFRE, a través del programa de Ayudas a la Investigación (2009

Recubrimientos no cristalinos en rocas graníticas de Galicia: propiedades e hipótesis sobre su origen

[Resumen] La caracterización de nuevos recubrimientos de bajo grado de orden en macizos graníticos de Galicia y el estudio de algunas propiedades de éstos y de otros previamente descritos, confirma la hipótesis de la existencia de una serie continua de materiales cuya composición varía entre la de fosfatos de aluminio (variscita, evansita),aluminosilicatos poco ordenados (alofanos geológicos, haloisita) e hidróxidos de aluminio (gel de alúmina hidratado,gibbsita). Del análisis de sus características y de algunas de sus propiedades como superficie específica, reacción frente a los ani ones fluoruro y fosfato, solubilidad en diferentes extractantes, punto cero de carga,etc., se establecen y discuten diversas hipótesis sobre su origen. Se discuten además relaciones de equilibrio o en el sistema Si02-A1203-P20~,confrontándolas con los datos de aguas de escorrentla y solución del suelo.[Abstract] The characterization of low order coatings that appear on granitic rocks of Galicia and the study of some of their properties confirm the existence of a continuous series between Al-phosphates (variscite,evan site),aluminium silicates (allophane,halloysite) ano Al-hydroxides (criptogibbsite,gibbsite).Several hypothe sis about their origin are discussed on the basis OT properties like specific surface, reaction with fluoride and phosphate, pze, solubility in different extracttants, etc . Finally, the theoretical equilibrium relations in the system A1203-Si02-P205 are confronted with the composition of dralnage waters and soil solutio

Squeezing resulting from a fourth-order interaction in a degenerate parametric amplifier with absorption losses

7 págs.; 8 figs.The squeezing properties of a model of a degenerate parametric amplifier with absorption losses and an added fourth-order nonlinearity have been analyzed. The approach used consists of obtaining the Langevin equation for the optical field from the Heisenberg equation provided that a linearization procedure is valid. The steady states of the deterministic equations have been obtained and their local stability has been analyzed. The stationary covariance matrix has been calculated below and above threshold. Below threshold, a squeezed vacuum state is obtained and the nonlinear effects in the fluctuations have been taken into account by a Gaussian decoupling. In the case above threshold, a phase-squeezed coherent state is obtained and numerical simulations allowed to compute the time interval, depending on the loss parameter, on which the system jumps from one stable state to the other. Finally, the variances numerically determined have been compared with those obtained from the linearized theory and the limits of validity of the linear theory have been analyzed. It has become clear that the nonlinear contribution may perhaps be profitably used for the construction of above-threshold squeezing devices. © 1991 The American Physical Society.Peer Reviewe

Effect of different exercise modalities plus a hypocaloric diet on inflammation markers in overweight patients

Summary Background & aims Inflammation markers (IM) have been associated with the development of chronic diseases. This study compares the effects on IM of three exercise programs combined with a hypocaloric diet. Methods 119 overweight participants (73 women, 46 men) aged 18–50 years were randomised into four treatment groups: strength training (S; n = 30), endurance training (E; n = 30), combined S + E (SE; n = 30), and a diet and physical activity recommendations group (D; n = 29). Energy intake, anthropometric variables (AV), training variables (VO2peak, strength index, dynamometric strength index [DSI]) and plasma IM were recorded at baseline and after 22 weeks of treatment. Results 84 participants completed the study. At 22 weeks, all groups showed a significantly reduced energy intake (P < 0.001) and improved AV (P < 0.001). VO2peak significantly increased in all groups (P < 0.01). DSI increased in the exercise groups only (P < 0.05). Plasma leptin fell significantly (P < 0.001) in the S and E groups, but not significantly in the SE group (P = 0.029) (no significant differences between these groups). Tumour necrosis factor-α (TNF-α), and C-reactive protein (CRP) concentrations decreased in all groups when examined together, but not when examined separately. No significant differences were seen in interleukin-6 (IL-6). Conclusions Combining strength or endurance training with a hypocaloric diet improved AV and reduced plasma leptin concentrations. No differences were seen between groups in terms of TNF-α, IL-6 or CRP reduction. This trial was registered at clinical trials.gov as NCT01116856. http://clinicaltrials.gov/

Crystallization of para-Hydrogen: a quantum phase transition at finite temperature?

4 págs.; 3 figs.; Open Access funded by Creative Commons Atribution Licence 3.0; 7th Meeting of the Spanish Neutron Scattering Association (SETN)Recent neutron scattering measurements have revealed that para-Hydrogen prepared in its fundamental state solidifies in a crystal that do not show temperature response (temperature independent molecular displacement and first rotational level linewidth as well as negligible thermal expansion). Here, it is argued that such unique behaviour in the crystal phase can be understood if the crystallization is driven by pure quantum fluctuations.Work supported in part by grants MAT2007-65711-C04-01 and MAT2012-33633 from the Spanish Ministerio de Economía y Competitividad.Peer Reviewe

Hormonal an inflammatory biomarkers in a group of overweight and obese women

Introducción y Objetivos: Recientemente se ha descubierto que la obesidad es una patología caracterizada por un estado crónico de inflamación leve. El objetivo de este estudio fue describir la situación hormonal e inflamatoria de un colectivo de mujeres con sobrepeso/obesidad. Pacientes y métodos: se incluyeron mujeres > 18 años, con IMC ≥ 25 < 40 kg/m2. Se recogieron datos socio-sanitarios, presión arterial, parámetros antropométricos, de actividad física, estudio bioquímico, hormonal e inflamatorio para determinar la situación hormonal e inflamatoria de un colectivo de mujeres antes del inicio de un tratamiento para el control de peso corporal. Resultados: participaron 104 mujeres con edad media de 48,4 ± 9 años y un IMC de 29,8 ± 3,5 kg/m2. Un 48% de las mujeres estudiadas se encontraba en etapa de menopausia. Un 8,9% presentó hiperinsulinemia. El valor medio obtenido de grhelina fue 38,8 ± 33,6 pg/ml, no se encontró correlación entre sus concentraciones y las variables antropométricas y bioquímicas estudiadas. Los valores medios de PCR, leptina, adiponectina, resistina, IL 6, IL 10 y PAI 1 fueron 3,0 ± 2,7 mg/dl, 36,3 ± 19,5 ng/ml, 8,3 ± 4,5 μg/ml, 24,3 ± 23,2 ng/ml, 51,6 ± 93,6 pg/ml, 10,0 ± 34,2 pg/ml y 22,3 ± 30,6 ng/ml, respectivamente. Estas concentraciones correlacionaron significativamente con diferentes variables antropométricas y bioquímicas, sin embargo, estas correlaciones fueron débiles. Variables como la edad y presencia o no de menopausia o la práctica de actividad física de forma regular no influyeron en los valores medios obtenidos. Las pacientes con obesidad tuvieron valores medios significativamente más elevados que aquellas con sobrepeso, aunque sólo en el caso de la resistina y PAI 1. Conclusión: El grupo de mujeres estudiadas presentó cifras de adipoquinas alteradas en relación a otros estudios realizados en población con situación nutricional normal. Esto pone en evidencia la situación inflamatoria presente en estos pacientes y los valores obtenidos pueden contribuir a establecer unos rangos normalizados de estos marcadores para el colectivo de personas con sobrepeso y obesidadBackground and objectives: The aim of this study was to describe the hormonal and inflammatory status of a group of overweight/obese women. Patients and methods: The sample studied was a crosssectional cohort of women > 18 years of age, BMI ≥ 25 < 40 kg/m2, prior to starting a weight control program. Data collected were: demographic characteristics, blood pressure, anthropometric parameters, physical activity data, and biochemical, hormonal and inflammatory biomarkers. Results: The study involved 104 women with a mean age of 48.4 ± 9 years and a BMI of 29.8 ± 3.5 kg/m2. Some 48% of the women studied were in menopause. Some 8.9% had hyperinsulinemia. The mean ghrelin value was 38.8 ± 33.6 pg/ml; there was no correlation between ghrelin levels and anthropometric and biochemical variables. CRP, leptin, adiponectin, resistin, IL6, IL10, and PAI1 were 3.0 ± 2.7 mg/dl, 36.3 ± 19.5 ng/ml, 8.3 ± 4.5 mg/ml, 24.3 ± 23.2 ng/ml, 51.6 ± 93.6 pg/ml, 10.0 ± 34.2 pg/ml and 22.3 ± 30.6 ng/ml, respectively. Obese patients had significantly higher mean values of resistin and PAI 1 than those who were overweight. These levels correlated significantly with anthropometric and biochemical variables; however, the correlations were weak. Age, menopause or the regular practice of physical activity had no effect on mean values. Conclusions: The group of women studied had altered inflammatory biomarkers in relation to people of normal weight. The study shows the inflammatory status of overweight/ obese individuals, and the values obtained may help to establish standard ranges for these markersEste trabajo ha sido posible gracias a un proyecto de investigación obtenido por concurso y subvencionado por la campaña “Pan cada día” promovida por el Comité Científico del Pan y el Incerhpan (Interprofesional Agroalimentaria de la cadena Cereales-Harina- Pan

Microscopic dynamics in molten Ni: Experimental scrutiny of embedded-atom-potential simulations

11 págs.; 10 figs. ; PACS number s : 66.10. x, 66.20. d, 63.20.LsThe stochastic dynamics in molten nickel is studied by neutron scattering. The quasielastic spectrum shows two distinct components having disparate linewidths. The wave-vector dependence of the narrow component is shown to arise from incoherent scattering at low momentum transfers. In turn, the spectral half-width of the wider component shows a modulation with wave vector characteristic of coherent quasielastic scattering. The analysis of both components provides direct experimental estimates for the self-diffusion coefficient, as well as the effective particle diameter. The experimental data are then used to validate computer simulation results which are derived using an embedded-atom potential. Such results are also employed to explore regions in frequency-wave-vector space not easily amenable to experiment. In addition, simulation results are also compared with data pertaining to the collective motions. Such an exercise reveals the need to develop a further level in the memory function expansion of the coherent dynamic structure factor. The implications of such findings for our current understanding of the dynamics of liquid metals are finally assessed. © 2007 The American Physical Society.Peer Reviewe

Collective excitations in liquid D2 confined within the mesoscopic pores of a MCM-41 molecular sieve

We present a comparative study of the excitations in bulk and liquid D2 confined within the pores of MCM-41. The material (Mobile Crystalline Material-41) is a silicate obtained by means of a template that yields a partially crystalline structure composed by arrays of nonintersecting hexagonal channels of controlled width having walls made of amorphous SiO2. Its porosity was characterized by means of adsorption isotherms and found to be composed by a regular array of pores having a narrow distribution of sizes with a most probable value of 2.45 nm. The assessment of the precise location of the sample within the pores is carried out by means of pressure isotherms. The study was conducted at two pressures which correspond to pore fillings above the capillary condensation regime. Within the range of wave vectors where collective excitations can be followed up (0.3<Q<3.0 $\AA$&#8722;1), we found confinement brings forward a large shortening of the excitation lifetimes that shifts the characteristic frequencies to higher energies. In addition, the coherent quasielastic scattering shows signatures of reduced diffusivity.Comment: 6 page

Stochastic dynamics in molten potassium explored by polarized quasielastic neutron scattering

10 págs.; 8 figs. ; PACS number s : 61.25.Mv, 66.10. x, 66.30.Fq, 65.20. wThe coherent Sc (Q,ω) and single-particle Ss (Q,ω) dynamic structure factors which contribute to the low-energy spectrum of molten potassium are separated by means of neutron polarization analysis. The linewidth and amplitude of the single-particle spectra follow an apparent sub-Fickian behavior, with a diffusion coefficient below the value found by macroscopic means. Once this is accounted for, the results are found to conform with predictions made from kinetic theory. Also, the available theoretical recipes to account for the coherent quasielastic intensity are seen to reproduce the experimental observations within a region of momentum transfers located about the location where the static structure factor shows its main peak. From the measured data as well as from computer simulation results which are validated by comparison to measurement, a clear separation of time scales involving rapid rattling motions within the liquid cages from diffusional processes involving collective or single-particle rearrangements is established. © 2007 The American Physical Society.Peer Reviewe