Social integration, health behaviors and health status among Mexican-American women in the *southwestern United States

Using the Hispanic Health and Nutrition Examination Survey (HHANES), this research examined several health behaviors and the health status of Mexican American women. This study focused on determining the relative impact of social contextual factors: age, socioeconomic status, quality of life indicators, and urban/rural residence on (a) health behaviors (smoking, obesity and alcohol use) and (b) health status (physician's assessment of health status, subject's assessment of health status and blood pressure levels). In addition, social integration was analyzed. The social integration indicators relate to an individual's degree of integration within his/her social group: marital status, level of acculturation (a continuum of traditional Mexican ways to dominant U.S. cultural ways), status congruency, and employment status. Lastly, the social contextual factors and social integration indicators were examined to identify those factors that contribute most to understanding health behaviors and health status among Mexican American women.^ The study found that the social contextual factors and social integration indicators proved to be important concepts in understanding the health behaviors. Social integration, however, did not predict health status except in the case of the subject's assessment of health status. Age and obesity were the strongest predictors of blood pressure. The social contextual factors and obesity were significant predictors of the physician's assessment of health status while acculturation, education, alcohol use and obesity were significant predictors of the subject's assessment of health status. ^

Yangtze River Delta's system integration: institutional barriers and countermeasures

This paper addresses the issue of institutional barriers to the Yangtze River Delta integration and the resulting slow development. It analyzes the problems including the coordination of local interests and regional interests, market segmentation during the regional integration, competition for the local government���s investment on the public goods, labor movement within the delta. The paper argues that to reduce the negative impacts of these barriers and to promote the further integration of the Yangtze Delta region, the central government should strengthen the coordination between local governments, regulate their disorderly competition and reform the official evaluation system.

Communication-efficient and crash-quiescent Omega with unknown membership

The failure detector class Omega (��) provides an eventual leader election functionality, i.e., eventually all correct processes permanently trust the same correct process. An algorithm is communication-efficient if the number of links that carry messages forever is bounded by n, being n the number of processes in the system. It has been defined that an algorithm is crash-quiescent if it eventually stops sending messages to crashed processes. In this regard, it has been recently shown the impossibility of implementing �� crash quiescently without a majority of correct processes. We say that the membership is unknown if each process pi only knows its own identity and the number of processes in the system (that is, i and n), but pi does not know the identity of the rest of processes of the system. There is a type of link (denoted by ADD link) in which a bounded (but unknown) number of consecutive messages can be delayed or lost. In this work we present the first implementation (to our knowledge) of �� in partially synchronous systems with ADD links and with unknown membership. Furthermore, it is the first implementation of �� that combines two very interesting properties: communication-efficiency and crash-quiescence when the majority of processes are correct. Finally, we also obtain with the same algorithm a failure detector () such that every correct process eventually and permanently outputs the set of all correct processes.

A repository for integration of software artifacts with dependency resolution and federation support

While developing new IT products, reusability of existing components is a key aspect that can considerably improve the success rate. This fact has become even more important with the rise of the open source paradigm. However, integrating different products and technologies is not always an easy task. Different communities employ different standards and tools, and most times is not clear which dependencies a particular piece of software has. This is exacerbated by the transitive nature of these dependencies, making component integration a complicated affair. To help reducing this complexity we propose a model-based repository, capable of automatically resolve the required dependencies. This repository needs to be expandable, so new constraints can be analyzed, and also have federation support, for the integration with other sources of artifacts. The solution we propose achieves these working with OSGi components and using OSGi itself.

The dicode workbench: A flexible framework for the integration of information and web services

Aiming to address requirements concerning integration of services in the context of ?big data?, this paper presents an innovative approach that (i) ensures a flexible, adaptable and scalable information and computation infrastructure, and (ii) exploits the competences of stakeholders and information workers to meaningfully confront information management issues such as information characterization, classification and interpretation, thus incorporating the underlying collective intelligence. Our approach pays much attention to the issues of usability and ease-of-use, not requiring any particular programming expertise from the end users. We report on a series of technical issues concerning the desired flexibility of the proposed integration framework and we provide related recommendations to developers of such solutions. Evaluation results are also discussed.

Review of the C-nat(n,gamma) cross section and criticality calculations of the graphite moderated reactor BR1

A review of the experimental data for natC(n,c) and 12C(n,c) was made to identify the origin of the natC capture cross sections included in evaluated data libraries and to clarify differences observed in neutronic calculations for graphite moderated reactors using different libraries. The performance of the JEFF-3.1.2 and ENDF/B-VII.1 libraries was verified by comparing results of criticality calculations with experimental results obtained for the BR1 reactor. This reactor is an air-cooled reactor with graphite as moderator and is located at the Belgian Nuclear Research Centre SCK-CEN in Mol (Belgium). The results of this study confirm conclusions drawn from neutronic calculations of the High Temperature Engineering Test Reactor (HTTR) in Japan. Furthermore, both BR1 and HTTR calculations support the capture cross section of 12C at thermal energy which is recommended by Firestone and R��vay. Additional criticality calculations were carried out in order to illustrate that the natC thermal capture cross section is important for systems with a large amount of graphite. The present study shows that only the evaluation carried out for JENDL-4.0 reflects the current status of the experimental data.

User Experience in Human-Technology Interaction. Communication, context and evaluation methodology

En esta Tesis se presentan dos l��neas de investigaci��n relacionadas y que contribuyen a las ��reas de Interacci��n Hombre-Tecnolog��a (o M��quina; siglas en ingl��s: HTI o HMI), ling����stica computacional y evaluaci��n de la experiencia del usuario. Las dos l��neas en cuesti��n son el dise��o y la evaluaci��n centrada en el usuario de sistemas de Interacci��n Hombre-M��quina avanzados. En la primera parte de la Tesis (Cap��tulos 2 a 4) se abordan cuestiones fundamentales del dise��o de sistemas HMI avanzados. El Cap��tulo 2 presenta una panor��mica del estado del arte de la investigaci��n en el ��mbito de los sistemas conversacionales multimodales, con la que se enmarca el trabajo de investigaci��n presentado en el resto de la Tesis. Los Cap��tulos 3 y 4 se centran en dos grandes aspectos del dise��o de sistemas HMI: un gestor del di��logo generalizado para tratar la Interacci��n Hombre-M��quina multimodal y sensible al contexto, y el uso de agentes animados personificados (ECAs) para mejorar la robustez del di��logo, respectivamente. El Cap��tulo 3, sobre gesti��n del di��logo, aborda el tratamiento de la heterogeneidad de la informaci��n proveniente de las modalidades comunicativas y de los sensores externos. En este cap��tulo se propone, en un nivel de abstracci��n alto, una arquitectura para la gesti��n del di��logo con influjos heterog��neos de informaci��n, apoy��ndose en el uso de State Chart XML. En el Cap��tulo 4 se presenta una contribuci��n a la representaci��n interna de intenciones comunicativas, y su traducci��n a secuencias de gestos a ejecutar por parte de un ECA, dise��ados espec��ficamente para mejorar la robustez en situaciones de di��logo cr��ticas que pueden surgir, por ejemplo, cuando se producen errores de entendimiento en la comunicaci��n entre el usuario humano y la m��quina. Se propone, en estas p��ginas, una extensi��n del Functional Mark-up Language definido en el marco conceptual SAIBA. Esta extensi��n permite representar actos comunicativos que realizan intenciones del emisor (la m��quina) que no se pretende sean captadas conscientemente por el receptor (el usuario humano), pero con las que se pretende influirle a ��ste e influir el curso del di��logo. Esto se consigue mediante un objeto llamado Base de Intenciones Comunicativas (en ingl��s, Communication Intention Base, o CIB). La representaci��n en el CIB de intenciones ���no claradas��� adem��s de las expl��citas permite la construcci��n de actos comunicativos que realizan simult��neamente varias intenciones comunicativas. En el Cap��tulo 4 tambi��n se describe un sistema experimental para el control remoto (simulado) de un asistente dom��tico, con autenticaci��n de locutor para dar acceso, y con un ECA en el interfaz de cada una de estas tareas. Se incluye una descripci��n de las secuencias de comportamiento verbal y no verbal de los ECAs, que fueron dise��ados espec��ficamente para determinadas situaciones con objeto de mejorar la robustez del di��logo. Los Cap��tulos 5 a 7 conforman la parte de la Tesis dedicada a la evaluaci��n. El Cap��tulo 5 repasa antecedentes relevantes en la literatura de tecnolog��as de la informaci��n en general, y de sistemas de interacci��n hablada en particular. Los principales antecedentes en el ��mbito de la evaluaci��n de la interacci��n sobre los cuales se ha desarrollado el trabajo presentado en esta Tesis son el Technology Acceptance Model (TAM), la herramienta Subjective Assessment of Speech System Interfaces (SASSI), y la Recomendaci��n P.851 de la ITU-T. En el Cap��tulo 6 se describen un marco y una metodolog��a de evaluaci��n aplicados a la experiencia del usuario con sistemas HMI multimodales. Se desarroll�� con este prop��sito un novedoso marco de evaluaci��n subjetiva de la calidad de la experiencia del usuario y su relaci��n con la aceptaci��n por parte del mismo de la tecnolog��a HMI (el nombre dado en ingl��s a este marco es Subjective Quality Evaluation Framework). En este marco se articula una estructura de clases de factores subjetivos relacionados con la satisfacci��n y aceptaci��n por parte del usuario de la tecnolog��a HMI propuesta. Esta estructura, tal y como se propone en la presente tesis, tiene dos dimensiones ortogonales. Primero se identifican tres grandes clases de par��metros relacionados con la aceptaci��n por parte del usuario: ���agradabilidad ��� (likeability: aquellos que tienen que ver con la experiencia de uso, sin entrar en valoraciones de utilidad), rechazo (los cuales s��lo pueden tener una valencia negativa) y percepci��n de utilidad. En segundo lugar, este conjunto clases se reproduce para distintos ���niveles, o focos, percepci��n del usuario���. ��stos incluyen, como m��nimo, un nivel de valoraci��n global del sistema, niveles correspondientes a las tareas a realizar y objetivos a alcanzar, y un nivel de interfaz (en los casos propuestos en esta tesis, el interfaz es un sistema de di��logo con o sin un ECA). En el Cap��tulo 7 se presenta una evaluaci��n emp��rica del sistema descrito en el Cap��tulo 4. El estudio se apoya en los mencionados antecedentes en la literatura, ampliados con par��metros para el estudio espec��fico de los agentes animados (los ECAs), la auto-evaluaci��n de las emociones de los usuarios, as�� como determinados factores de rechazo (concretamente, la preocupaci��n por la privacidad y la seguridad). Tambi��n se eval��a el marco de evaluaci��n subjetiva de la calidad propuesto en el cap��tulo anterior. Los an��lisis de factores efectuados revelan una estructura de par��metros muy cercana conceptualmente a la divisi��n de clases en utilidad-agradabilidad-rechazo propuesta en dicho marco, resultado que da cierta validez emp��rica al marco. An��lisis basados en regresiones lineales revelan estructuras de dependencias e interrelaci��n entre los par��metros subjetivos y objetivos considerados. El efecto central de mediaci��n, descrito en el Technology Acceptance Model, de la utilidad percibida sobre la relaci��n de dependencia entre la intenci��n de uso y la facilidad de uso percibida, se confirma en el estudio presentado en la presente Tesis. Adem��s, se ha encontrado que esta estructura de relaciones se fortalece, en el estudio concreto presentado en estas p��ginas, si las variables consideradas se generalizan para cubrir m��s ampliamente las categor��as de agradabilidad y utilidad contempladas en el marco de evaluaci��n subjetiva de calidad. Se ha observado, asimismo, que los factores de rechazo aparecen como un componente propio en los an��lisis de factores, y adem��s se distinguen por su comportamiento: moderan la relaci��n entre la intenci��n de uso (que es el principal indicador de la aceptaci��n del usuario) y su predictor m��s fuerte, la utilidad percibida. Se presentan tambi��n resultados de menor importancia referentes a los efectos de los ECAs sobre los interfaces de los sistemas de di��logo y sobre los par��metros de percepci��n y las valoraciones de los usuarios que juegan un papel en conformar su aceptaci��n de la tecnolog��a. A pesar de que se observa un rendimiento de la interacci��n dialogada ligeramente mejor con ECAs, las opiniones subjetivas son muy similares entre los dos grupos experimentales (uno interactuando con un sistema de di��logo con ECA, y el otro sin ECA). Entre las peque��as diferencias encontradas entre los dos grupos destacan las siguientes: en el grupo experimental sin ECA (es decir, con interfaz s��lo de voz) se observ�� un efecto m��s directo de los problemas de di��logo (por ejemplo, errores de reconocimiento) sobre la percepci��n de robustez, mientras que el grupo con ECA tuvo una respuesta emocional m��s positiva cuando se produc��an problemas. Los ECAs parecen generar inicialmente expectativas m��s elevadas en cuanto a las capacidades del sistema, y los usuarios de este grupo se declaran m��s seguros de s�� mismos en su interacci��n. Por ��ltimo, se observan algunos indicios de efectos sociales de los ECAs: la ���amigabilidad ��� percibida los ECAs estaba correlada con un incremento la preocupaci��n por la seguridad. Asimismo, los usuarios del sistema con ECAs tend��an m��s a culparse a s�� mismos, en lugar de culpar al sistema, de los problemas de di��logo que pudieran surgir, mientras que se observ�� una ligera tendencia opuesta en el caso de los usuarios del sistema con interacci��n s��lo de voz. ABSTRACT This Thesis presents two related lines of research work contributing to the general fields of Human-Technology (or Machine) Interaction (HTI, or HMI), computational linguistics, and user experience evaluation. These two lines are the design and user-focused evaluation of advanced Human-Machine (or Technology) Interaction systems. The first part of the Thesis (Chapters 2 to 4) is centred on advanced HMI system design. Chapter 2 provides a background overview of the state of research in multimodal conversational systems. This sets the stage for the research work presented in the rest of the Thesis. Chapers 3 and 4 focus on two major aspects of HMI design in detail: a generalised dialogue manager for context-aware multimodal HMI, and embodied conversational agents (ECAs, or animated agents) to improve dialogue robustness, respectively. Chapter 3, on dialogue management, deals with how to handle information heterogeneity, both from the communication modalities or from external sensors. A highly abstracted architectural contribution based on State Chart XML is proposed. Chapter 4 presents a contribution for the internal representation of communication intentions and their translation into gestural sequences for an ECA, especially designed to improve robustness in critical dialogue situations such as when miscommunication occurs. We propose an extension of the functionality of Functional Mark-up Language, as envisaged in much of the work in the SAIBA framework. Our extension allows the representation of communication acts that carry intentions that are not for the interlocutor to know of, but which are made to influence him or her as well as the flow of the dialogue itself. This is achieved through a design element we have called the Communication Intention Base. Such r pr s ntation of ���non- clar ��� int ntions allows th construction of communication acts that carry several communication intentions simultaneously. Also in Chapter 4, an experimental system is described which allows (simulated) remote control to a home automation assistant, with biometric (speaker) authentication to grant access, featuring embodied conversation agents for each of the tasks. The discussion includes a description of the behavioural sequences for the ECAs, which were designed for specific dialogue situations with particular attention given to the objective of improving dialogue robustness. Chapters 5 to 7 form the evaluation part of the Thesis. Chapter 5 reviews evaluation approaches in the literature for information technologies, as well as in particular for speech-based interaction systems, that are useful precedents to the contributions of the present Thesis. The main evaluation precedents on which the work in this Thesis has built are the Technology Acceptance Model (TAM), the Subjective Assessment of Speech System Interfaces (SASSI) tool, and ITU-T Recommendation P.851. Chapter 6 presents the author���s work in establishing an valuation framework and methodology applied to the users��� experience with multimodal HMI systems. A novel user-acceptance Subjective Quality Evaluation Framework was developed by the author specifically for this purpose. A class structure arises from two orthogonal sets of dimensions. First we identify three broad classes of parameters related with user acceptance: likeability factors (those that have to do with the experience of using the system), rejection factors (which can only have a negative valence) and perception of usefulness. Secondly, the class structure is further broken down into several ���user perception levels���; at the very least: an overall system-assessment level, task and goal-related levels, and an interface level (e.g., a dialogue system with or without an ECA). An empirical evaluation of the system described in Chapter 4 is presented in Chapter 7. The study was based on the abovementioned precedents in the literature, expanded with categories covering the inclusion of an ECA, the users��� s lf-assessed emotions, and particular rejection factors (privacy and security concerns). The Subjective Quality Evaluation Framework proposed in the previous chapter was also scrutinised. Factor analyses revealed an item structure very much related conceptually to the usefulness-likeability-rejection class division introduced above, thus giving it some empirical weight. Regression-based analysis revealed structures of dependencies, paths of interrelations, between the subjective and objective parameters considered. The central mediation effect, in the Technology Acceptance Model, of perceived usefulness on the dependency relationship of intention-to-use with perceived ease of use was confirmed in this study. Furthermore, the pattern of relationships was stronger for variables covering more broadly the likeability and usefulness categories in the Subjective Quality Evaluation Framework. Rejection factors were found to have a distinct presence as components in factor analyses, as well as distinct behaviour: they were found to moderate the relationship between intention-to-use (the main measure of user acceptance) and its strongest predictor, perceived usefulness. Insights of secondary importance are also given regarding the effect of ECAs on the interface of spoken dialogue systems and the dimensions of user perception and judgement attitude that may have a role in determining user acceptance of the technology. Despite observing slightly better performance values in the case of the system with the ECA, subjective opinions regarding both systems were, overall, very similar. Minor differences between two experimental groups (one interacting with an ECA, the other only through speech) include a more direct effect of dialogue problems (e.g., non-understandings) on perceived dialogue robustness for the voice-only interface test group, and a more positive emotional response for the ECA test group. Our findings further suggest that the ECA generates higher initial expectations, and users seem slightly more confident in their interaction with the ECA than do those without it. Finally, mild evidence of social effects of ECAs was also found: the perceived friendliness of the ECA increased security concerns, and ECA users may tend to blame themselves rather than the system when dialogue problems are encountered, while the opposite may be true for voice-only users.

Multimodal integration of functional and structural brain connectivity. An application to the characterization of Mild Cognitive Impairment

La investigaci��n para el conocimiento del cerebro es una ciencia joven, su inicio se remonta a Santiago Ram��n y Cajal en 1888. Desde esta fecha a nuestro tiempo la neurociencia ha avanzado mucho en el desarrollo de t��cnicas que permiten su estudio. Desde la neurociencia cognitiva hoy se explican muchos modelos que nos permiten acercar a nuestro entendimiento a capacidades cognitivas complejas. Aun as�� hablamos de una ciencia casi en pa��ales que tiene un lago recorrido por delante. Una de las claves del ��xito en los estudios de la funci��n cerebral ha sido convertirse en una disciplina que combina conocimientos de diversas ��reas: de la f��sica, de las matem��ticas, de la estad��stica y de la psicolog��a. Esta es la raz��n por la que a lo largo de este trabajo se entremezclan conceptos de diferentes campos con el objetivo de avanzar en el conocimiento de un tema tan complejo como el que nos ocupa: el entendimiento de la mente humana. Concretamente, esta tesis ha estado dirigida a la integraci��n multimodal de la magnetoencefalograf��a (MEG) y la resonancia magn��tica ponderada en difusi��n (dMRI). Estas t��cnicas son sensibles, respectivamente, a los campos magn��ticos emitidos por las corrientes neuronales, y a la microestructura de la materia blanca cerebral. A lo largo de este trabajo hemos visto que la combinaci��n de estas t��cnicas permiten descubrir sinergias estructurofuncionales en el procesamiento de la informaci��n en el cerebro sano y en el curso de patolog��as neurol��gicas. M��s espec��ficamente en este trabajo se ha estudiado la relaci��n entre la conectividad funcional y estructural y en c��mo fusionarlas. Para ello, se ha cuantificado la conectividad funcional mediante el estudio de la sincronizaci��n de fase o la correlaci��n de amplitudes entre series temporales, de esta forma se ha conseguido un ��ndice que mide la similitud entre grupos neuronales o regiones cerebrales. Adicionalmente, la cuantificaci��n de la conectividad estructural a partir de im��genes de resonancia magn��tica ponderadas en difusi��n, ha permitido hallar ��ndices de la integridad de materia blanca o de la fuerza de las conexiones estructurales entre regiones. Estas medidas fueron combinadas en los cap��tulos 3, 4 y 5 de este trabajo siguiendo tres aproximaciones que iban desde el nivel m��s bajo al m��s alto de integraci��n. Finalmente se utiliz�� la informaci��n fusionada de MEG y dMRI para la caracterizaci��n de grupos de sujetos con deterioro cognitivo leve, la detecci��n de esta patolog��a resulta relevante en la identificaci��n precoz de la enfermedad de Alzheimer. Esta tesis est�� dividida en seis cap��tulos. En el cap��tulos 1 se establece un contexto para la introducci��n de la connect��mica dentro de los campos de la neuroimagen y la neurociencia. Posteriormente en este cap��tulo se describen los objetivos de la tesis, y los objetivos espec��ficos de cada una de las publicaciones cient��ficas que resultaron de este trabajo. En el cap��tulo 2 se describen los m��todos para cada t��cnica que fue empleada: conectividad estructural, conectividad funcional en resting state, redes cerebrales complejas y teor��a de grafos y finalmente se describe la condici��n de deterioro cognitivo leve y el estado actual en la b��squeda de nuevos biomarcadores diagn��sticos. En los cap��tulos 3, 4 y 5 se han incluido los art��culos cient��ficos que fueron producidos a lo largo de esta tesis. Estos han sido incluidos en el formato de la revista en que fueron publicados, estando divididos en introducci��n, materiales y m��todos, resultados y discusi��n. Todos los m��todos que fueron empleados en los art��culos est��n descritos en el cap��tulo 2 de la tesis. Finalmente, en el cap��tulo 6 se concluyen los resultados generales de la tesis y se discuten de forma espec��fica los resultados de cada art��culo. ABSTRACT In this thesis I apply concepts from mathematics, physics and statistics to the neurosciences. This field benefits from the collaborative work of multidisciplinary teams where physicians, psychologists, engineers and other specialists fight for a common well: the understanding of the brain. Research on this field is still in its early years, being its birth attributed to the neuronal theory of Santiago Ramo��n y Cajal in 1888. In more than one hundred years only a very little percentage of the brain functioning has been discovered, and still much more needs to be explored. Isolated techniques aim at unraveling the system that supports our cognition, nevertheless in order to provide solid evidence in such a field multimodal techniques have arisen, with them we will be able to improve current knowledge about human cognition. Here we focus on the multimodal integration of magnetoencephalography (MEG) and diffusion weighted magnetic resonance imaging. These techniques are sensitive to the magnetic fields emitted by the neuronal currents and to the white matter microstructure, respectively. The combination of such techniques could bring up evidences about structural-functional synergies in the brain information processing and which part of this synergy fails in specific neurological pathologies. In particular, we are interested in the relationship between functional and structural connectivity, and how two integrate this information. We quantify the functional connectivity by studying the phase synchronization or the amplitude correlation between time series obtained by MEG, and so we get an index indicating similarity between neuronal entities, i.e. brain regions. In addition we quantify structural connectivity by performing diffusion tensor estimation from the diffusion weighted images, thus obtaining an indicator of the integrity of the white matter or, if preferred, the strength of the structural connections between regions. These quantifications are then combined following three different approaches, from the lowest to the highest level of integration, in chapters 3, 4 and 5. We finally apply the fused information to the characterization or prediction of mild cognitive impairment, a clinical entity which is considered as an early step in the continuum pathological process of dementia. The dissertation is divided in six chapters. In chapter 1 I introduce connectomics within the fields of neuroimaging and neuroscience. Later in this chapter we describe the objectives of this thesis, and the specific objectives of each of the scientific publications that were produced as result of this work. In chapter 2 I describe the methods for each of the techniques that were employed, namely structural connectivity, resting state functional connectivity, complex brain networks and graph theory, and finally, I describe the clinical condition of mild cognitive impairment and the current state of the art in the search for early biomarkers. In chapters 3, 4 and 5 I have included the scientific publications that were generated along this work. They have been included in in their original format and they contain introduction, materials and methods, results and discussion. All methods that were employed in these papers have been described in chapter 2. Finally, in chapter 6 I summarize all the results from this thesis, both locally for each of the scientific publications and globally for the whole work.

Short communication. Collection and characterisation of a population of Triticum boeoticum Boiss., a wild wheat species not previously found in the Mediterranean western region

En julio del 2010 se recolect�� una poblaci��n de trigo silvestre en una zona abandonada cerca de Madrid, Espa��a. Esta zona posee una biodiversidad bot��nica elevada y un tipo de suelo muy peculiar denominado ���arcillas verdes���. Se recogi�� una muestra de trigo y se multiplic�� y caracteriz�� para varios caracteres agro-morfol��gicos y subunidades de gluteninas. El n��mero cromos��mico 2n de las semillas demostr�� que es una especie diploide de trigo y los datos de caracterizaci��n indicaron que es Triticum boeoticum Boiss. Esta especie lleg�� probablemente como mala hierba del cultivo de esca��a que se produc��a en la zona hasta al menos la primera mitad del s. xix. Las caracter��sticas ed��ficas y clim��ticas del lugar y el hecho de que no haya referencias hasta ahora de esta especie en la zona oeste de la regi��n Mediterr��nea aumentan el valor de esta adquisici��n para la mejora del trigo. La nueva accesi��n se conserva en el Centro Nacional de Recursos Fitogen��ticos y se ha depositado una hoja de herbario en el Real Jard��n Bot��nico de Madrid

Molecular uncoupling of C-C chemokine receptor 5-induced chemotaxis and signal transduction from HIV-1 coreceptor���activity

The C-C chemokine receptor 5 (CCR5) plays a crucial role in facilitating the entry of macrophage-tropic strains of the HIV-1 into cells, but the mechanism of this phenomenon is completely unknown. To explore the role of CCR5-derived signal transduction in viral entry, we introduced mutations into two cytoplasmic domains of CCR5 involved in receptor-mediated function. Truncation of the terminal carboxyl-tail to eight amino acids or mutation of the highly conserved aspartate-arginine-tyrosine, or DRY, sequence in the second cytoplasmic loop of CCR5 effectively blocked chemokine-dependent activation of classic second messengers, intracellular calcium fluxes, and the cellular response of chemotaxis. In contrast, none of the mutations altered the ability of CCR5 to act as an HIV-1 coreceptor. We conclude that the initiation of signal transduction, the prototypic function of G protein coupled receptors, is not required for CCR5 to act as a coreceptor for HIV-1 entry into cells.

c-Abl is required for development and optimal cell proliferation in the context of p53 deficiency

The c-Abl tyrosine kinase and the p53 tumor suppressor protein interact functionally and biochemically in cellular genotoxic stress response pathways and are implicated as downstream mediators of ATM (ataxia-telangiectasia mutated). This fact led us to study genetic interactions in vivo between c-Abl and p53 by examining the phenotype of mice and cells deficient in both proteins. c-Abl-null mice show high neonatal mortality and decreased B lymphocytes, whereas p53-null mice are prone to tumor development. Surprisingly, mice doubly deficient in both c-Abl and p53 are not viable, suggesting that c-Abl and p53 together contribute to an essential function required for normal development. Fibroblasts lacking both c-Abl and p53 were similar to fibroblasts deficient in p53 alone, showing loss of the G1/S cell-cycle checkpoint and similar clonogenic survival after ionizing radiation. Fibroblasts deficient in both c-Abl and p53 show reduced growth in culture, as manifested by reduction in the rate of proliferation, saturation density, and colony formation, compared with fibroblasts lacking p53 alone. This defect could be restored by reconstitution of c-Abl expression. Taken together, these results indicate that the ATM phenotype cannot be explained solely by loss of c-Abl and p53 and that c-Abl contributes to enhanced proliferation of p53-deficient cells. Inhibition of c-Abl function may be a therapeutic strategy to target p53-deficient cells selectively.

Integration of circadian and phototransduction pathways in the network controlling CAB gene transcription in���Arabidopsis

The transcription of CAB genes, encoding the chlorophyll a/b-binding proteins, is rapidly induced in dark-grown Arabidopsis seedlings following a light pulse. The transient induction is followed by several cycles of a circadian rhythm. Seedlings transferred to continuous light are known to exhibit a robust circadian rhythm of CAB expression. The precise waveform of CAB expression in light���dark cycles, however, reflects a regulatory network that integrates information from photoreceptors, from the circadian clock and possibly from a developmental program. We have used the luciferase reporter system to investigate CAB expression with high time resolution. We demonstrate that CAB expression in light-grown plants exhibits a transient induction following light onset, similar to the response in dark-grown seedlings. The circadian rhythm modulates the magnitude and the kinetics of the response to light, such that the CAB promoter is not light responsive during the subjective night. A signaling pathway from the circadian oscillator must therefore antagonize the phototransduction pathways controlling the CAB promoter. We have further demonstrated that the phase of maximal CAB expression is delayed in light���dark cycles with long photoperiods, due to the entrainment of the circadian oscillator. Under short photoperiods, this pattern of entrainment ensures that dawn coincides with a phase of high light responsiveness, whereas under long photoperiods, the light response at dawn is reduced.

Differential requirement of the cytoplasmic subregions of ��c chain in T cell development and function

The common cytokine receptor �� chain (��c), a shared component of the receptors for IL-2, IL-4, IL-7, IL-9, and IL-15, is critical for the development and function of lymphocytes. The cytoplasmic domain of ��c consists of 85 aa, in which the carboxyl-terminal 48 aa are essential for its interaction with and activation of the Janus kinase, Jak3. Evidence has been provided that Jak3-independent signals might be transmitted via the residual membrane-proximal region; however, its role in vivo remains totally unknown. In the present study, we expressed mutant forms of ��c, which lack either most of the cytoplasmic domain or only the membrane-distal Jak3-binding region, on a ��c null background. We demonstrate that, unlike ��c or Jak3 null mice, expression of the latter, but not the former mutant, restores T lymphopoiesis in vivo, accompanied by strong expression of Bcl-2. On the other hand, the in vitro functions of the restored T cells still remained impaired. These results not only reveal the hitherto unknown role of the ��c membrane-proximal region, but also suggest the differential requirement of the cytoplasmic subregions of ��c in T cell development and function.

Kinetic coupling between electron and proton transfer in cytochrome c oxidase: simultaneous measurements of conductance and absorbance changes.

Bovine heart cytochrome c oxidase is an electron-current driven proton pump. To investigate the mechanism by which this pump operates it is important to study individual electron- and proton-transfer reactions in the enzyme, and key reactions in which they are kinetically and thermodynamically coupled. In this work, we have simultaneously measured absorbance changes associated with electron-transfer reactions and conductance changes associated with protonation reactions following pulsed illumination of the photolabile complex of partly reduced bovine cytochrome c oxidase and carbon monoxide. Following CO dissociation, several kinetic phases in the absorbance changes were observed with time constants ranging from approximately 3 microseconds to several milliseconds, reflecting internal electron-transfer reactions within the enzyme. The data show that the rate of one of these electron-transfer reactions, from cytochrome a3 to a on a millisecond time scale, is controlled by a proton-transfer reaction. These results are discussed in terms of a model in which cytochrome a3 interacts electrostatically with a protonatable group, L, in the vicinity of the binuclear center, in equilibrium with the bulk through a proton-conducting pathway, which determines the rate of proton transfer (and indirectly also of electron transfer). The interaction energy of cytochrome a3 with L was determined independently from the pH dependence of the extent of the millisecond-electron transfer and the number of protons released, as determined from the conductance measurements. The magnitude of the interaction energy, 70 meV (1 eV = 1.602 x 10(-19) J), is consistent with a distance of 5-10 A between cytochrome a3 and L. Based on the recently determined high-resolution x-ray structures of bovine and a bacterial cytochrome c oxidase, possible candidates for L and a physiological role for L are discussed.

A mutant p53 antagonizes the deregulated c-myc-mediated enhancement of apoptosis and decrease in leukemogenicity.

Myeloid leukemic M1 cells that do not express p53 and transfected M1 clones that constitutively express the [Val135]p53 mutant or deregulated c-myc or coexpressing both genes grew autonomously in culture with a similar growth rate and cloning efficiency. Expression of deregulated c-myc in M1 leukemic cells enhanced susceptibility to induction of apoptotic cell death and resulted in a reduced leukemogenicity when injected into isologous mice. Expression of the [Val135]p53 mutant did not change cell susceptibility to induction of apoptosis or leukemogenicity, but expression of this mutant p53 suppressed the effects of deregulated c-myc on these properties. The results indicate that the [Val135]p53 mutant can show a gain of function for susceptibility to apoptosis and leukemogenicity in leukemic cells with deregulated c-myc and, thus, enhance tumor development.