Structural properties of fluids interacting via piece-wise constant potentials with a hard core

The structural properties of fluids whose molecules interact via potentials with a hard core plus two piece-wise constant sections of different widths and heights are presented. These follow from the more general development previously introduced for potentials with a hard core plus $n$ piece-wise constant sections [Condens. Matter Phys. {\bf 15}, 23602 (2012)] in which use was made of a semi-analytic rational-function approximation method. The results of illustrative cases comprising eight different combinations of wells and shoulders are compared both with simulation data and with those that follow from the numerical solution of the Percus-Yevick and hypernetted-chain integral equations. It is found that the rational-function approximation generally predicts a more accurate radial distribution function than the Percus-Yevick theory and is comparable or even superior to the hypernetted-chain theory. This superiority over both integral equation theories is lost, however, at high densities, especially as the widths of the wells and/or the barriers increase.Comment: 10 pages, 11 figures; v2: Old Fig. 1 removed, new text on the correlation length, 7 new references added, plus other minor change

Vapor-liquid surface tension of strong short-range Yukawa fluid

The thermodynamic properties of strong short-range attractive Yukawa fluids, k=10, 9, 8, and 7, are determined by combining the slab technique with the standard and the replica exchange Monte Carlo (REMC) methods. A good agreement was found among the coexistence curves of these systems calculated by REMC and those previously reported in the literature. However, REMC allows exploring the coexistence at lower temperatures, where dynamics turns glassy. To obtain the surface tension we employed, for both methods, a procedure that yields the pressure tensor components for discontinuous potentials. The surface tension results obtained by the standard MC and REMC techniques are in good agreement.Comment: 6 pages, 4 figure

Effect of high pressure processing on wheat dough and bread characteristics

8 pages, 3 figures, 4 tables.-- Available online 30 June 2009.Microbial, physical and structural changes in high pressured wheat dough were studied as a function of pressure level (50–250 MPa) and holding time (1–4 min). Thereafter, selected conditions of high hydrostatic processing (HPP) were applied to bread dough and the technological quality of the obtained breads was studied. The effect of HPP on wheat dough was investigated by determining microbial population (total aerobic mesophilic bacteria, moulds and yeasts), color and mechanical and texture surface related dough parameters (cohesiveness, adhesiveness, hardness and stickiness). HPP reduced the endogenous microbial population of wheat dough from 10^4 colony forming units/g (CFU) to levels of 10^2 CFU. HPP treatment significantly (P < 0.05) increased dough hardness and adhesiveness, whereas treatment time reduced its stickiness. Scanning electron micrographs suggested that proteins were affected when subjected to pressure levels higher than 50 MPa, but starch modification required higher pressure levels. HPP treated yeasted doughs led to wheat breads with different appearance and technological characteristics; crumb acquired brownish color and heterogeneous cell gas distribution with increased hardness due to new crumb structure. This study suggests that high hydrostatic processing in the range 50–200 MPa could be an alternative technique for obtaining novel textured cereal based products.This work was financially supported by Spanish Ministerio de Ciencia e Innovación Project (AGL2005-05192-C04-01), Consejo Superior de Investigaciones Científicas (CSIC) and Mexican Consejo Nacional de Ciencia y Tecnología (CONACYT).Peer reviewe

Effect of water activity in tortilla and its relationship on the acrylamide content after frying

The objective of this study was to relate the tortilla minimum integral desorption entropy with acrylamide content during processing of tortilla chips. Tortilla pieces were stored at 30 °C at aw of 0.11-0.84 for 4 days and fried later in soybean oil at 180 °C for 25 s. The lowest acrylamide content was observed in tortilla chips made of non-stored tortilla (aw = 0.98) as well as in those prepared from tortilla stored in the minimum integral entropy (aw = 0.53). In addition, the color and texture values were similar in both cases. These results suggest that the reduction of the acrylamide content during processing of tortilla chips and other tortilla based foods thermally processed might be modified by factors such as moisture content, aw, and the physical state of water in the tortilla. Thus, the minimum integral entropy showed to be a reliable indicator to establish the most appropriate moisture conditions to obtain tortilla chips with reduced level of acrylamide when tortilla is dehydrated. © 2014 Elsevier Ltd. All rights reserved.We are indebted to Juan Veles, Edmundo Gutierrez, Carlos Alberto Ávila, Araceli Mauricio and Veronica Flores from CINVESTAV Querétaro for their technical assistance.Peer Reviewe

Guadalfeo and Adra submarine deltas evolution in response to sediment supply variations

The Guadalfeo and the Adra submarine deltas off the northern coast of the Alboran Sea have been built up under the direct influence of short and mountainous rivers. The area is subjected to strong climatic seasonality, with sporadic winter torrential floods and high summer aridity. In addition numerous anthropogenic activities have affected these systems, mostly during the last two centuries. In order to decode the influence of climatic variability and anthropogenic impacts on sediment supplies during the recent past, five sediment cores were collected from the Guadalfeo and Adra submarine deltas. Benthic foraminiferal and sedimentological analyses, combined with radiocarbon dating, were performed. The impact of torrential floods alternating with periods of low rainfall or dry periods were recorded in the Adra and Guadalfeo prodeltas. Periods with low abundance of benthic foraminifera and high amounts of coarse-grained sediments, were interpreted as the result of enhanced sediment supply to the shelf triggered by major flood events. On the other hand, periods with high amounts of fine-grained sediments and high abundances of colonizers and opportunistic foraminiferal species indicate the establishment of new environments with distinct ecological constraints. These environments were driven by lower sediment supplies during low rainfall or dry periods. The most recent sedimentation seems to reflect the human interventions in the rivers basins, such as deviation of the main river courses and dams construction, which reduced the sediment input and promoted the deposition of shallow-water submarine deltas.info:eu-repo/semantics/publishedVersio

El estado de la teoría del diseño en tronco común y la licenciatura en Arquitectura

El presente trabajo se encuentra dividido en tres secciones que hemos denominado: el acto histórico,el acto teórico y conclusión. En el primero se plantea la necesidad de abordar al diseño como perteneciente a las denominadas ciencias de la cultura, esbozando los nexos que existen entre la filosofía de la cultura y la filosofía de la historia. De ello deviene una primera referencia a la obra material humana como perteneciente a una reflexión inicial que lo desprende de la naturaleza, rasgo común presente todas las sociedades que históricamente han existido. Toda cultura humana ha diseñado como rasgo ontológico básico, rasgo que le ha permitido su supervivencia sobre el planeta. En el segundo apartado se determina el fenómeno como tal que nos permite referir una teoría del diseño: su manifestación, su presencia como integrante de lo fenómenos puros, y la relación posterior que existe entre el fenómeno y su entorno, sea natural o social, o en la síntesis y presencia de ambos. De ello se desprende la determinación de la problemática por seguir en los cursos de Fundamentos Teóricos del Diseño I y II. Establecida tal relación, se ofrece una propuesta de vinculación entre las materias correspondientes al Tronco Común y a las llamadas Teoría e Historia de la Arquitectura

A study on dual square free modules

Let M be an H-supplemented coatomic module with FIEP. Then we prove that M is dual square free if and only if every maximal submodule ofM is fully invariant. Let M = ⊕ i∈I Mi be a direct sum, such that M is coatomic. Then we prove that M is dual square free if and only if each Mi is dual square free for all i ∈ I and, Mi and ⊕ j̸≠i Mj are dual orthogonal. Finally we study the endomorphism rings of dual square free modules. Let M be a quasi-projective module. If EndR(M) is right dual square free, then M is dual square free. In addition, if M is finitely generated, then EndR(M) is right dual square free whenever M is dual square free. We give several examples illustrating our hypotheses

Estudio sobre la marchitez del ajonjolí en el Departamento del Tolima.

Se presenta información sobre sintomatología, pruebas de patogenicidad y resistencia varietal de una grave enfermedad que ha afectado el ajonjolí en el Departamento del Tolima. La enfermedad se caracteriza por una marchitez inicial del follaje y lesiones necróticas en el tallo y ramas secundarias de color pardo oscuro con decoloración de los haces vasculares. En las pruebas de patogenicidad el hongo Macrophomina sp. posiblemente M. phaseoli, aislado del material afectado, produjo consistentemente los síntomas típicos de la enfermedad 36 horas después de inoculado en plantas de la variedad susceptible Chino Rojo. Las pruebas de resistencia varietal bajo condiciones de infección natural en el campo mostraron que las variedades introducidas Paloma, Glauca, Baco, Genesa y Early Russian, tenían una alta resistencia pero con rendimientos inferiores a las variedades comerciales. Las selecciones Línea 507, Línea 609 e Instituto 104 se comportaron como resistentes con rendimientos superiores a los 1000 kg/haAjonjolí-Sésamo - Sesamum indicu