The Stationary Phase Method for a Wave Packet in a Semiconductor Layered System. The applicability of the method

Using the formal analysis made by Bohm in his book, {\em "Quantum theory"}, Dover Publications Inc. New York (1979), to calculate approximately the phase time for a transmitted and the reflected wave packets through a potential barrier, we calculate the phase time for a semiconductor system formed by different mesoscopic layers. The transmitted and the reflected wave packets are analyzed and the applicability of this procedure, based on the stationary phase of a wave packet, is considered in different conditions. For the applicability of the stationary phase method an expression is obtained in the case of the transmitted wave depending only on the derivatives of the phase, up to third order. This condition indicates whether the parameters of the system allow to define the wave packet by its leading term. The case of a multiple barrier systems is shown as an illustration of the results. This formalism includes the use of the Transfer Matrix to describe the central stratum, whether it is formed by one layer (the single barrier case), or two barriers and an inner well (the DBRT system), but one can assume that this stratum can be comprise of any number or any kind of semiconductor layers.Comment: 15 pages, 4 figures although figure 4 has 5 graph

Characterization of plant growth promoting bacteria isolated from red fruits. Studies on growth promotion and fruit quality in strawberry plants

Microorganisms associated to the rizosphere of plants cultivated plants for human consumption are scarcely analyzed. However,nowadays, organic farming  where the use of microbial inoculants is essential, has arisenas emergent alternative with a great commercial interest.In this study, the characterization of the bacterial microbiotic presents in the rhizosphere of strawberry and blueberry plants has been carried out. In particular, three relevant characteristics have been determined order  to classify he isolated strains as plant growth promoting bacteria (PGPB). These characteristics are: 1) the ability to produce auxins, 2) siderophores and 3)  the solubilization of phosphates presents in the medium.On the other hand, the behavior of bacterial strains previously identified as PGPB has been studied in strawberry plants  both in greenhouse and field trials. The plants located in the greenhouse, were inoculated with the endophytic strawberries isolated strains: LTE1, LTE2, LTE3, LTE4, LTE6, EF12a, EF35 and EF113, as well as with three blueberries insolated bacteria which possess a high leves of auxin production, named AC8, ACH2 and ACH7. The strawberries plants located in the field, were inoculated with the strains Hv16, Hvs8 and Rec3.At the greenhouse trials, production parameters (precocity in flowering, number and weight of fruits) as well as biometrical parameters at the end of the trial, the fresh and dry weigth of root and shoots will be analyzed. At the field trial, the following production parameters will be evaluated: number and weight of extra-early fruit (February), number and weight of early fruit (March) and number and weight of total fruit. Quality fruit parameters as color, shape, sugar content (ºBrix), acidity, pH, vitamin C and anthocyanin content will be determined twice, once in February and again at the end of the experiment. By the time, the micro and macro-nutrient will also be analyzaed

ANÁLISIS DEL VALOR DE MARCA DE LAS ENTIDADES FINANCIERAS: EL EFECTO HALO Y EL MODELO DE ELECCIÓN DISCRETA

El presente trabajo trata de cuantificar el valor de marca y el posicionamiento de las entidades financieras en dos mercados diferentes: consumidores finales y microempresas. Así mismo, se busca identificar las dimensiones de imagen de mayor peso a la hora de elegir a una entidad como la de mejor valoración global. A través del modelo de elección discreta y del análisis del efecto halo ,se comprueba la importancia del trato personal al cliente como la variable de mayor peso en la elección de marca. Además, se observa la mayor intensidad del efecto halo para las cajas de ahorros en el caso de los consumidores particulares. Sin embargo, en el segmento de microempresas, el valor de marca es superior para los bancos

Anaerobic Thermophilic Colonization of Porous Support

Biofilm development in an open-pore sintered glass material (SIRAN) was studied using a laboratory-scale anaerobic fixed-film bioreactor under thermophilic conditions. The startup and performance of that bioreactor, operating on distillery waste water feed (vinasses), were also studied. Results obtained indicated that stepped organic loading during initial bioreactor start-up reduced the periods of adaptation in the colonization process and micro-organism attachment and biofilm formation was accelerated by the surface characteristics of the carrier. The results obtained by operating with stepped organic loading (& = 2.0 kg m–3 d–1 COD) over a period of 70 days suggest that a stable operation of the process (90% COD removal) and high density of biomass immobilized on the support (20 kgVSatt per m3 SIRAN) is achieved. Epifluorescence microscopy demonstrated that, initially, attached growth was developed in crevices, where biomass was protected from shear forces and, finally, SIRAN was completely covered and biofilm developed on the entire SIRAN particles

The extent to which genetics and lean grade affect fatty acid profiles and volatile compounds in organic pork

Niche production is intended to produce premium pork, but several husbandry factors may affect the meat fatty acid composition and aroma. Fatty acid profile (by GC-FID) of raw meat and volatile compounds (by SPME-GC-MS) of cooked meat were analysed in loin samples from two pig genetic types-75% Duroc (Du) and 50% Pietrain (Pi) rossbreds that were slaughtered at different weights (90 kg and 105 kg, respectively) to achieve similar target carcass fatness, and the outcome carcasses were balanced for lean grade groups (<60% or ≥60% lean) within genotypes. Genetic type did not affect fatty acids (FA) profile of meat. The leaner meat had lower C12:0 and C20:3n − 3, lower saturated fatty acids (SFA) and higher MUFA/SFA ratio content than the fattier meat. Short-chain alcohols were lower in Pietrain and in leaner pork compared to the samples from Duroc crossbreds and fattier pork. A greater amount of hexane,2,4,4-trimethyl (an aliphatic hydrocarbon) but lower carbon disulphide (sulphur compound) content was detected in pork from leaner compared to fattier pork. Higher aromatics hydrocarbons were exclusively associated with Duroc crossbreds, and lower aliphatic hydrocarbons with pigs classified as fattier. Most of the volatile compounds detected in the present study came from lipid oxidation.José Manuel Lorenzo is a member of the MARCARNE network, funded by CYTED (ref.116RT0503). The funders had no role in study design, data collection and analysis, decisionto publish, or preparation of the manuscript

Point defects on graphene on metals

Understanding the coupling of graphene with its local environment is critical to be able to integrate it in tomorrow's electronic devices. Here we show how the presence of a metallic substrate affects the properties of an atomically tailored graphene layer. We have deliberately introduced single carbon vacancies on a graphene monolayer grown on a Pt(111) surface and investigated its impact in the electronic, structural and magnetic properties of the graphene layer. Our low temperature scanning tunneling microscopy studies, complemented by density functional theory, show the existence of a broad electronic resonance above the Fermi energy associated with the vacancies. Vacancy sites become reactive leading to an increase of the coupling between the graphene layer and the metal substrate at these points; this gives rise to a rapid decay of the localized state and the quenching of the magnetic moment associated with carbon vacancies in free-standing graphene layers

Dietary Options for Rodents in the Study of Obesity

Abstract: Obesity and its associated metabolic diseases are currently a priority research area. The increase in global prevalence at different ages is having an enormous economic and health impact. Genetic and environmental factors play a crucial role in the development of obesity, and diet is one of the main factors that contributes directly to the obesogenic phenotype. Scientific evidence has shown that increased fat intake is associated with the increase in body weight that triggers obesity. Rodent animal models have been extremely useful in the study of obesity since weight gain can easily be induced with a high-fat diet. Here, we review the dietary patterns and physiological mechanisms involved in the dynamics of energy balance. We report the main dietary options for the study of obesity and the variables to consider in the use of a high-fat diet, and assess the progression of obesity and diet-induced thermogenesis. Keywords: obesity; diet; high-fat diet; diet-induced thermogenesis; body mass index; rodent

Desarrollo de un programa multimedia de aprendizaje en Reproducción Animal

The complexity of the veterinary curriculum is a challenge to prepare educational material in an interdisciplinary manner. Multimedia programs develop on the new computer-assisted learning systems are an appropiate medium for making such educational material available, in a efficient way, easy to update, and the expenses are moderate. Students can handle this program without difficulty, and visual components (graphics, images, movies) can promote the subject-student interaction. A multimedia program dealing with the Animal Reproduction has been developed by Reproduction and Obstetric Unit at the Faculty of Veterinary of Cordoba to support the student's educational formation. Male and female reproductive selection and examination in different animal species is approach in this multimedia application.La complejidad del currículum de veterinaria es un desafío para la preparación de material educacional de manera interdisplinar. Los actuales sistemas de enseñanza asistida por ordenador permiten que tutoriales o programas multimedia de aprendizaje en soportes informáticos se hayan convertido en un medio adecuado para conseguir que este material educativo se encuentre disponible de una manera eficaz, fácil de actualizar y con unos costes moderados. Los estudiantes pueden manejar dichos programas sin mucha complicación, siendo atractivos -entre otras razones- por la facilidad para incorporar en ellos componentes visuales (gráficos, imágenes, vídeos), lo que promueve la interacción entre asignaturas y alumno. En este sentido, la Unidad de Reproducción y Obstreticia de la Facultad de Veterinaria de Córdoba ha desarrollado un programa multimedia de aprendizaje en Reproducción Animal, que ofrece al estudiante un apoyo para su formación. Aborda temas relacionados con la selección y valoración de hembras y machos como reproductores, en las distintas especies animales