Antioxidant activity of alkyl gallates and glycosyl alkyl gallates in fish oil in water emulsions: Relevance of their surface active properties and of the type of emulsifier

The antioxidant activity of gallic acid and a series of alkyl gallates (C4-C18) and glycosylated alkyl gallates (C4-C18) on fish oil-in-water emulsions was studied. Three types of emulsifiers, lecithin, Tween-20 and sodium dodecyl sulphate (SDS) were tested. A nonlinear behavior of the antioxidant activity of alkyl gallates when increasing alkyl chain length was observed for emulsions prepared with lecithin. Medium-size alkyl gallates (C6-C12) were the best antioxidants. In contrast, for emulsions prepared with Tween-20, the antioxidants seem to follow the polar paradox. Glucosyl alkyl gallates were shown previously to be better surfactants than alkyl gallates. Nevertheless, they exhibited a worse antioxidant capacity than their corresponding alkyl gallates, in emulsions prepared with lecithin or Tween-20, indicating the greater relevance of having three OH groups at the polar head in comparison with having improved surfactant properties but just a di-ortho phenolic structure in the antioxidant

Pulsations in M dwarf stars

We present the results of the first theoretical non-radial non-adiabatic pulsational study of M dwarf stellar models with masses in the range 0.1 to 0.5M_solar. We find the fundamental radial mode to be unstable due to an \epsilon mechanism caused by deuterium (D-) burning for the young 0.1 and 0.2M_solar models, by non-equilibrium He^3 burning for the 0.2 and 0.25M_solar models of 10^4Myr, and by a flux blocking mechanism for the partially convective 0.4 and 0.5M_solar models once they reach the age of 500Myr. The periods of the overstable modes excited by the D-burning are in the range 4.2 to 5.2h for the 0.1M_solar models and is of order 8.4h for the 0.2M_solar models. The periods of the modes excited by He^3 burning and flux blocking are in the range 23 to 40min. The more massive and oldest models are more promising for the observational detection of pulsations, as their ratio of instability e-folding time to age is more favourable.Comment: 5 pages, 4 figures, 2 tables. Accepted for publication in MNRAS Letters on 2011 October 11 Version 2 is the accepted manuscript with changes in boldfac

Evaluación de la calidad biológica del suelo en un Sistema Agroforestal de especies maderables nativas (Pilón y Almendro) con Heliconias y un Bosque Secundario, en la zona de Limón. Costa Rica

Debido a que poco se conoce sobre la calidad biológica del suelo en los sistemas agroforestales de especies maderables nativas y flores tropicales como las heliconias, se consideró importante realizar el presente estudio, con el objetivo de evaluar la calidad biológica del suelo en un sistema agroforestal (SAF) con heliconias y compararlo con un bosque secundario (BS), con el fin de determinar el efecto del sistema agroforestal en el suelo. Este fue efectuado en la Finca Capinal S.A, ubicada en Guácimo de Limón, Costa Rica; donde se realizó un muestreo sistemático al azar, en ambos sitios (1.5 ha cada uno), de las propiedades químicas (micro y macro nutrientes y materia orgánica), físicas (textura, densidad aparente y porcentaje de porosidad), biológicas (biomasa y número de lombrices) y bioquímicas (biomasa microbiana) del suelo. Para el análisis de los datos se realizó un Análisis de Comparación Estadística de Muestras Múltiples y ANOVA, mediante la utilización del programa StatGraphics. La cantidad de MO encontrada en los suelos de la Finca Capinal (6,43% para el BS y 5,76% SAF), se encuentra dentro del rango normal para suelos Inceptisoles de la zona (5,0-7,4%), con niveles más altos en el BS. Con respecto a la densidad de lombrices, no se presentaron diferencias significativas; sin embargo, el BS reflejo una mayor población (28,9% más), lo que tiene relación con un mayor cantidad de MO. La actividad microbiana fue mayor en el BS (5,18 % superior al SAF) y mantiene una correlación positiva con el contenido de MO y la densidad de lombrices. Considerando lo anterior y la falta de significancia estadística entre sistemas (BS y SAF), se concluye que ambos sitios presentan calidades biológicas del suelo similares

Design of a case management model for people with chronic disease (Heart Failure and COPD). Phase I: modeling and identification of the main components of the intervention through their actors: patients and professionals (DELTA-ICE-PRO Study

Background Chronic diseases account for nearly 60% of deaths around the world. The extent of this silent epidemic has not met determined responses in governments, policies or professionals in order to transform old Health Care Systems, configured for acute diseases. There is a large list of research about alternative models for people with chronic conditions, many of them with an advanced practice nurse as a key provider, as case management. But some methodological concerns raise, above all, the design of the intervention (intensity, frequency, components, etc). Methods/Design Objectives: General: To develop the first and second phases (theorization and modeling) for designing a multifaceted case-management intervention in people with chronic conditions (COPD and heart failure) and their caregivers. Specific aims: 1) To identify key events in people living with chronic disease and their relation with the Health Care System, from their point of view. 2) To know the coping mechanisms developed by patients and their caregivers along the story with the disease. 3) To know the information processing and its utilization in their interactions with health care providers. 4) To detect potential unmet needs and the ways deployed by patients and their caregivers to resolve them. 5) To obtain a description from patients and caregivers, about their itineraries along the Health Care System, in terms of continuity, accessibility and comprehensiveness of care. 6) To build up a list of promising case-management interventions in patients with Heart Failure and COPD with this information in order to frame it into theoretical models for its reproducibility and conceptualization. 7) To undergo this list to expert judgment to assess its feasibility and pertinence in the Andalusian Health Care. Design: Qualitative research with two phases: For the first five objectives, a qualitative technique with biographic stories will be developed and, for the remaining objectives, an expert consensus through Delphi technique, on the possible interventions yielded from the first phase. The study will be developed in the provinces of Almería, Málaga and Granada in the Southern Spain, from patients included in the Andalusian Health Care Service database with the diagnosis of COPD or Heart Failure, with the collaboration of case manager nurses and general practitioners for the assessment of their suitability to inclusion criteria. Patients and caregivers will be interviewed in their homes or their Health Centers, with their family or their case manager nurse as mediator. Discussion First of a series of studies intended to design a case-management service for people with heart failure and COPD, in the Andalusian Health Care System, where case management has been implemented since 2002. Accordingly with the steps of a theoretical model for complex interventions, in this study, theorization and intervention modeling phases will be developed.This research was carried out with the support of one research grant, awarded by the Regional Health Ministry of Andalusia (Exp. 0222/2008

Análisis sobre la influencia de la densidad en la termografía de infrarrojos y el alcance de esta técnica en la detección de defectos internos en la madera

This paper shows the results of a laboratory phase for the determination of the 1limits of infrared thermography in detecting internal defects in wood and, furthermore, it analyses how the density of this material can influence the surface temperature displayed in a thermogram. To this end, experimental work is carried out whereby a series of work and environmental parameters are monitored (such as environmental temperature, relative humidity, distance to target), and the process is systematized by using pieces of different wood species (different densities) and by devising a set of samples for which various possible cases are analysed in terms of size and internal position of the damage. Similarly, using these samples, a study has been conducted on the effect on the thermal image produced by an increase of humidity inside the defect phenomena normally associated with wood decay.En el presente artículo se muestran los resultados obtenidos en una fase de laboratorio al tratar de determinar el alcance de la termografía de infrarrojos en la detección de defectos internos en la madera y, por otro lado, cómo interviene la densidad de este material sobre la temperatura superficial mostrada en un termograma. Para ello se ha desarrollado un trabajo experimental donde se han controlado una serie de parámetros ambientales y de trabajo (temperatura ambiente, humedad relativa, distancia al objetivo…), y se ha sistematizado el proceso utilizando piezas de distintas especies de madera (distintas densidades) y diseñando una serie de probetas donde se han analizado varias casuísticas posibles en cuanto a tamaño y posición interna de los daños. Análogamente, sobre estas probetas se ha estudiado el efecto que produce sobre la imagen termográfica un incremento de humedad interna en el defecto asociada normalmente a los fenómenos de pudrición de la madera

Comprehensive transient-state study for CARMENES-NIR high thermal stability

CARMENES has been proposed as a next-generation instrument for the 3.5m Calar Alto Telescope. Its objective is finding habitable exoplanets around M dwarfs through radial velocity measurements (m/s level) in the near-infrared. Consequently, the NIR spectrograph is highly constraint regarding thermal/mechanical requirements. As a first approach, the thermal stability has been limited to \pm 0.01K (within year period) over a working temperature of 243K. This can be achieved by means of several temperature-controlled rooms. The options considered to minimise the complexity of the thermal design are here presented, as well as the transient-state thermal analyses realised to make the best choice

La Técnica de Grupo Nominal como herramienta para seleccionar ítems que miden el nivel de competencias digitales en estudiantes de posgrado

Digital competence has become crucial in the digital era and understanding the digital skills level of postgraduate students is essential to adapt educational programs and develop effective teaching and learning strategies. The objective of this research was to select the items of a questionnaire to assess the level of digital skills in postgraduate students in a specific situation, using the Nominal Group Technique (NGT). Study participants were selected for their experience and knowledge in the field of digital skills. A structured discussion was held in which the experts identified and discussed the key dimensions and components of digital competences relevant to postgraduate students, and the most representative items that would measure the level of digital skills in students were prioritized and selected. The outcomes provided a set of validated and reliable items included in a questionnaire that is tailored to previously identified digital skills. This questionnaire can effectively assess the level of digital skills in postgraduate students in a specific context, the outcomes of which help inform educational policies and strategies that improve digital skills training in reference students.La competencia digital se ha vuelto crucial en la era digital y comprender el nivel de competencias digitales de los estudiantes de posgrado es fundamental para adaptar los programas educativos y desarrollar estrategias efectivas de enseñanza y aprendizaje. El objetivo de esta investigación fue seleccionar los ítems de un cuestionario para evaluar el nivel de competencias digitales en estudiantes de posgrado en un contexto específico, utilizando la Técnica de Grupo Nominal (TGN). Los participantes del estudio fueron seleccionados por su experiencia y conocimientos en el campo de las competencias digitales. Se realizó una discusión estructurada en la que los expertos identificaron y debatieron las dimensiones y los componentes clave de las competencias digitales relevantes para los estudiantes de posgrado, y se priorizaron y seleccionaron los ítems más representativos que medirían el nivel de competencias digitales en los estudiantes. Los resultados proporcionaron un conjunto de ítems validados y confiables incluidos en un cuestionario que se adapta a las competencias digitales identificadas previamente. Este cuestionario puede evaluar de manera efectiva el nivel de competencias digitales en los estudiantes de posgrado en un contexto específico, cuyos resultados ayuden a informar políticas y estrategias educativas que mejoren la formación en competencias digitales en los estudiantes de referencia

Quiralidad en las ciencias naturales: un acercamiento a distintas escalas

The terms right and left are applicable beyond everyday life and living beings. The fingers on the right hand are arranged in relation to the center of the hand, which is not identical or superimposable to that of the left hand. Both variants are symmetrical versions, but not identical. The spatial arrangement can be observed not only in objects, but also in trajectories. For example, in the bats’ flight trajectories. In this article some examples of the chirality condition at different organization levels are defined and some of the recent advances on the subject are mentioned. Understanding the origin of chiral asymmetry found in particles, molecules, and macromolecules, allows us to infer current questions such as chemical evolution, the origin of life, and aspects related to evolution and the development of living beings, among others. Los términos derecha e izquierda son aplicables más allá de la cotidianidad humana y los seres vivos. Los dedos de la mano derecha tienen una disposición respecto al centro de la mano, que no es idéntica o superponible a aquella de la mano izquierda. Ambas variantes son versiones simétricas, pero no idénticas. El arreglo espacial puede observarse no solo en objetos, sino también en trayectorias. Por ejemplo, en las trayectorias del vuelo de los murciélagos. En el presente artículo se definen algunos ejemplos de la condición de quiralidad en distintos niveles de organización y se mencionan algunos de los recientes avances en el tema. Entender el origen de la asimetría quiral encontrada en partículas, moléculas, y macromoléculas, permite inferir preguntas vigentes como la evolución.