843 resultados para Historic conscience. Country of Mossoró . Memory. Spatiality.
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La biblioclasta fue definida como la compulsin humana por destruir libros. Desde tiempos inmemoriales el hombre ha querido imponer sus ideas a travs de la destruccin de aquellas que se contraponan a las propias y los libros han sido objeto de esa "pulsin biblioclstica" durante toda la historia de la humanidad. La ltima dictadura militar que sufri nuestro pas dej importantes secuelas en la sociedad. Mediante la censura e intervencin en diferentes mbitos (educacin, cine, teatro, literatura, entre otros) se construyeron un discurso, un lenguaje y unas prcticas que hoy se reconocen como propias de ese tiempo histrico. Igual que pas con la desaparicin de las personas y sus cuerpos, la represin en el mbito de la cultura fue parte de un plan sistemtico, pensado, calculado y llevado a cabo por dependencias del Estado argentino destinadas a tal fin y por funcionarios (militares y civiles) que fueron parte de ese plan. Se considera de especial importancia que los bibliotecarios, como parte de aqullos profesionales que contribuyen da a da a la preservacin de la memoria, abordemos este tipo de problemticas y reflexionemos en torno de la mismas. Este trabajo se enmarca en las investigaciones sobre el pasado reciente, teniendo como eje la Declaracin Universal de los Derechos Humanos y su postura frente a la libertad de expresin. Intenta reconstruir los mecanismos censorios y cmo se plasmaron en las vivencias de diferentes actores relacionados con el mbito del libro y del movimiento cultural y poltico platense, con el objetivo de contribuir a la memoria social de nuestra ciudad.
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Haiti, conocida en la poca colonial como 'la Perla de las Antillas', su economa se organiz entorno a la produccin de azcar que provean a travs de Francia al resto de Europa. De este modo 70de la produccin de azcar era consumido en Europa y ms del 60del caf. Con una lgica que persegua obtener los mximos rindes, buscaron mano de obra esclava en el frica Subsahariana, poblacin que directamente reemplaz a la originaria. As comienza a plantearse el desarrollo de un tipo de economa en Haiti, que traera graves consecuencias ambientales hasta la actualidad. Hoy es el pas ms pobre de Amrica, con una esperanza de vida de alrededor de 60 aos, y la tasa de analfabetismo del 52. Ubicado en un rea tropical, es frecuente que sufra el impacto de las tormentas tropicales y ciclones que, como consecuencia de una tala desmedida de laforestacin originaria, las inundaciones acentan los problemas, a lo que se suman los problemas sanitarios inherentes a un nivel de vida con tantas carencias; y a la preponderancia de minifundios en el rea rural, llevan a conformar un escenario de enorme vulnerabilidad. En el ao 2010, una triste noticia pondra a Hati en el centro de la escena mundial: el terremoto de marzo de ese ao que afectara el rea de Puerto Prncipe dejando alrededor de 300.000 muertos y ms de un milln de damnificados. En la actualidad la presencia debarrios enteros viviendo en carpas en espacios pblicos, son una expresin de la vigencia de dicho evento. Sin embargo, desde mediados de la dcada pasada tienen lugar proyectos que intentan territorializar una experiencia argentina de reconocido impacto en procura de atender las necesidades de la poblacin con mayor vulnerabilidad que habita en los espacios rurales. Se trata del Programa Pro Huerta, que desde hace ms de veinte aos se desarrolla en Argentina y se propuso en el mbito de este pas desde la perspectiva de la cooperacin internacional. De este modo, en distintos departamentos de Haiti con el trabajo en conjunto de diversos pases ponen en marcha un proyecto social de seguridad alimentaria. La finalidad es el anlisis de la territorializacin de la experiencia Pro Huerta Haiti a partir del enfoque de cooperacin internacional del cual Argentina participa junto con Canad y Haiti. Entre los resultados y aportes de esta investigacin, se pudo constatar que en Hat se fortalecen las redes sociales, la familia, el trabajo solidario, la salud y en conjunto contribuyen a fortalecer la soberana alimentaria, en un pas con grandes carencias y gran vulnerabilidad. Asimismo, es interesante resaltar que el modelo de Cooperacin Sur-Sur que la Argentina desarrolla, desde una visin horizontal donde nuestro pas camina junto a Hait y Canad en el aprendizaje cotidiano del crecimiento conjunto, donde cada pas tiene mucho por seguir aprendiendo
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El trabajo analiza cmo la exposicin presentada en el Museo Nacional de la Inmigracin fue aprehendida e interpretada por su pblico visitante. Dependiente de la Direccin Nacional de Migraciones, el Museo funcion entre los aos 2001 y 2009 en el edificio del antiguo Hotel de Inmigrantes (en Retiro). Para este estudio utilizamos ms de 700 mensajes registrados en el Libro de Visitas del Museo, que fueron clasificados en nueve categoras, de acuerdo a los aspectos comunes que expresaban. A lo largo del anlisis, el concepto de memoria se volvi fundamental para comprender los sentimientos y deseos expresados por el pblico que visit la institucin. Dentro de los temas que aparecieron en los mensajes, pudimos verificar la importancia que le atribuan los visitantes al Estado argentino por la construccin del Hotel, la recepcin de los inmigrantes y, actualmente, por la preservacin de su memoria y patrimonio; tambin se evidenci un agradecimiento a los inmigrantes, cuya "fuerza" y "esperanza" contribuyeron al desarrollo del pas
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Algunos escritores exiliados a partir de la ltima dictadura militar argentina (1976-1983) tradujeron ellos mismos sus textos para publicarlos en el pas de exilio. Un ejemplo es el de Alicia Partnoy, autora de The Little School. Tales of Disappearance & Survival in Argentina, quien habiendo escrito un testimonio en espaol sobre su paso por el campo de concentracin La Escuelita, ubicado en Baha Blanca, se dedic a traducirlo al ingls para su publicacin en Estados Unidos en 1986. Sus numerosas ediciones, primero en el extranjero y ms tarde en Argentina, lo ubican entre una de las obras ms importantes de la narrativa testimonial concentracionaria argentina. Una forma de abordarlo reside en el anlisis sobre el proceso y el resultado de la autotraduccin, lo cual permite aportar elementos de reflexin acerca de la necesidad de los supervivientes exiliados de dar a conocer su experiencia en el exilio, algo que sobrepasa, incluso, las barreras lingsticas
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Focus of this study is the analysis of a local hydrogeological system in the subhumid outer tropics in the western African country of Benin. The aim was to characterize, qualify and quantify the hydrogeological and hydrological properties of the approx. 30 km2 big study area and to develop a conceptual hydrogeological model. This model should provide the basis for further studies on a regional scale. The main goal was to obtain the process knowledge of the hydrogeological system and to determine the process and the quantity of the groundwater recharge in the working area. According to the objectives, a broad hydrogeological approach was chosen. In a spacious network on the local scale TDR probes, suction cups and groundwater observation bores were installed. Also in a multidisciplinary cooperation with hydrology, geography, soil science, biology, meteorology and plant nutrition sciences, instruments like discharge gauging stations, tensiometers, lysimeter, climate stations, runoff plots and erosion pins were installed in the test site for the investigation of the relevant parameters of the hydrological cycle.
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Infrastructure development means for the making of living environment, transport and communications, disaster prevention and national land conservation, agriculture, forestry and fisheries, and energy production and supply. Transport infrastructure development in Cambodia involved with (1) road, (2) railway, (3) port, inland-water way and (4) aviation. All model of transport infrastructure have special different kinds of importance. Railway is different from other base important of railways are transport passengers and traffic freight especially transport for heavy goods in huge capacity and in long distance by safer and faster. Transport in Cambodia for traffic freight export import base from Thailand and other via Sisophon and Shihanoukvill port. Traffic is increasing rapidly during nowadays railway condition in adequate of demand required. This is why Railway is selected as the topic of this paper to prevent monopoly of road transport. This paper, does review about infrastructure development plan for Railway in Cambodia as a long term strategy by review and analysis forecast on the previous performance of Royal Railways of Cambodia (RRC) transport traffic involved with condition of infrastructure development of railway in Cambodia. And also review the plan of development RRC but just only detail a plan of rehabilitation that is immediately needed. Suggest some recommendation at the last part. As Cambodia is a member country of ASEAN and also Mekong sub-region. For make sure that transport networks work effectively with a progress of economic integration, we make clear what is important for infrastructure development of railway in Cambodia from the standpoint of the development plan of Mekong sub-region. This paper is organized by 4 sections. Section 1 review about Infrastructure Development of Railway in Cambodia (IDRC) Historical Background, Follow by Section 2 will review the Current Situation of IDRC and some analysis of transport performance from previous years, Then Section 3 review of the focusing on traffic transport of RRC in the future, Section 4 review Infrastructure Development of Railway in Cambodia Future plans in long term; at last conclusion and recommendation. In section 1 does review history background of RRC from the rail first begun. But why is needed to review? Because of history background is involved infrastructure development of RRC in present time. History background made big gaps constraint and obstacle for socioeconomic development and poverty reduction, also left Cambodia with tragedy and left developed behind. After that remain infrastructure development needs huge fund and long time for restoration, reconstruction, rehabilitation and development into new technology as most of world practice.
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Labor export has been part of Vietnams socio-economic development strategy since the beginning of the doi moi era. Recent years, Vietnam has sent about 80,000 workers abroad per year. Vietnam has become a major source country of unskilled foreign workers for high-income East Asian countries. However, in these receiving countries, the desertion rate among Vietnamese workers is quite high, compared with that for workers from other countries. This paper examines the impact of Korean and Japanese policies for receiving foreign workers applied to and implemented in Vietnam, as well as the impact of Vietnamese labor sending system, on the problem of runaway workers.
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As in each country of Europe with nuclear power, there is a clear gap between those generation that have built the power plants in the eighties and the new generations with less than ten years of experience in the nuclear field. From its creation, Spanish Young Generation in Nuclear (Jvenes Nucleares) has as an important scope to help transferring the knowledge between those generations in the way that it can be possible. Some years ago, JJNN have started organizing seminars periodically trying to cover as many areas as possible in the nuclear engineering field, and some of them outside the industry but related with it.
Resumo:
El inters cada vez mayor por las redes de sensores inalmbricos pueden ser entendido simplemente pensando en lo que esencialmente son: un gran nmero de pequeos nodos sensores autoalimentados que recogen informacin o detectan eventos especiales y se comunican de manera inalmbrica, con el objetivo final de entregar sus datos procesados a una estacin base. Los nodos sensores estn densamente desplegados dentro del rea de inters, se pueden desplegar al azar y tienen capacidad de cooperacin. Por lo general, estos dispositivos son pequeos y de bajo costo, de modo que pueden ser producidos y desplegados en gran numero aunque sus recursos en trminos de energa, memoria, velocidad de clculo y ancho de banda estn enormemente limitados. Deteccin, tratamiento y comunicacin son tres elementos clave cuya combinacin en un pequeo dispositivo permite lograr un gran nmero de aplicaciones. Las redes de sensores proporcionan oportunidades sin fin, pero al mismo tiempo plantean retos formidables, tales como lograr el mximo rendimiento de una energa que es escasa y por lo general un recurso no renovable. Sin embargo, los recientes avances en la integracin a gran escala, integrado de hardware de computacin, comunicaciones, y en general, la convergencia de la informtica y las comunicaciones, estn haciendo de esta tecnologa emergente una realidad. Del mismo modo, los avances en la nanotecnologa estn empezando a hacer que todo gire entorno a las redes de pequeos sensores y actuadores distribuidos. Hay diferentes tipos de sensores tales como sensores de presin, acelermetros, cmaras, sensores trmicos o un simple micrfono. Supervisan las condiciones presentes en diferentes lugares tales como la temperatura, humedad, el movimiento, la luminosidad, presin, composicin del suelo, los niveles de ruido, la presencia o ausencia de ciertos tipos de objetos, los niveles de tensin mecnica sobre objetos adheridos y las caractersticas momentneas tales como la velocidad , la direccin y el tamao de un objeto, etc. Se comprobara el estado de las Redes Inalmbricas de Sensores y se revisaran los protocolos ms famosos. As mismo, se examinara la identificacin por radiofrecuencia (RFID) ya que se est convirtiendo en algo actual y su presencia importante. La RFID tiene un papel crucial que desempear en el futuro en el mundo de los negocios y los individuos por igual. El impacto mundial que ha tenido la identificacin sin cables est ejerciendo fuertes presiones en la tecnologa RFID, los servicios de investigacin y desarrollo, desarrollo de normas, el cumplimiento de la seguridad y la privacidad y muchos ms. Su potencial econmico se ha demostrado en algunos pases mientras que otros estn simplemente en etapas de planificacin o en etapas piloto, pero aun tiene que afianzarse o desarrollarse a travs de la modernizacin de los modelos de negocio y aplicaciones para poder tener un mayor impacto en la sociedad. Las posibles aplicaciones de redes de sensores son de inters para la mayora de campos. La monitorizacin ambiental, la guerra, la educacin infantil, la vigilancia, la micro-ciruga y la agricultura son solo unos pocos ejemplos de los muchsimos campos en los que tienen cabida las redes mencionadas anteriormente. Estados Unidos de Amrica es probablemente el pas que ms ha investigado en esta rea por lo que veremos muchas soluciones propuestas provenientes de ese pas. Universidades como Berkeley, UCLA (Universidad de California, Los ngeles) Harvard y empresas como Intel lideran dichas investigaciones. Pero no solo EE.UU. usa e investiga las redes de sensores inalmbricos. La Universidad de Southampton, por ejemplo, est desarrollando una tecnologa para monitorear el comportamiento de los glaciares mediante redes de sensores que contribuyen a la investigacin fundamental en glaciologa y de las redes de sensores inalmbricos. As mismo, Coalesenses GmbH (Alemania) y Zurich ETH estn trabajando en diversas aplicaciones para redes de sensores inalmbricos en numerosas reas. Una solucin espaola ser la elegida para ser examinada ms a fondo por ser innovadora, adaptable y polivalente. Este estudio del sensor se ha centrado principalmente en aplicaciones de trfico, pero no se puede olvidar la lista de ms de 50 aplicaciones diferentes que ha sido publicada por la firma creadora de este sensor especfico. En la actualidad hay muchas tecnologas de vigilancia de vehculos, incluidos los sensores de bucle, cmaras de video, sensores de imagen, sensores infrarrojos, radares de microondas, GPS, etc. El rendimiento es aceptable, pero no suficiente, debido a su limitada cobertura y caros costos de implementacin y mantenimiento, especialmente este ultimo. Tienen defectos tales como: lnea de visin, baja exactitud, dependen mucho del ambiente y del clima, no se puede realizar trabajos de mantenimiento sin interrumpir las mediciones, la noche puede condicionar muchos de ellos, tienen altos costos de instalacin y mantenimiento, etc. Por consiguiente, en las aplicaciones reales de circulacin, los datos recibidos son insuficientes o malos en trminos de tiempo real debido al escaso nmero de detectores y su costo. Con el aumento de vehculos en las redes viales urbanas las tecnologas de deteccin de vehculos se enfrentan a nuevas exigencias. Las redes de sensores inalmbricos son actualmente una de las tecnologas ms avanzadas y una revolucin en la deteccin de informacin remota y en las aplicaciones de recogida. Las perspectivas de aplicacin en el sistema inteligente de transporte son muy amplias. Con este fin se ha desarrollado un programa de localizacin de objetivos y recuento utilizando una red de sensores binarios. Esto permite que el sensor necesite mucha menos energa durante la transmisin de informacin y que los dispositivos sean ms independientes con el fin de tener un mejor control de trfico. La aplicacin se centra en la eficacia de la colaboracin de los sensores en el seguimiento ms que en los protocolos de comunicacin utilizados por los nodos sensores. Las operaciones de salida y retorno en las vacaciones son un buen ejemplo de por qu es necesario llevar la cuenta de los coches en las carreteras. Para ello se ha desarrollado una simulacin en Matlab con el objetivo localizar objetivos y contarlos con una red de sensores binarios. Dicho programa se podra implementar en el sensor que Libelium, la empresa creadora del sensor que se examinara concienzudamente, ha desarrollado. Esto permitira que el aparato necesitase mucha menos energa durante la transmisin de informacin y los dispositivos sean ms independientes. Los prometedores resultados obtenidos indican que los sensores de proximidad binarios pueden formar la base de una arquitectura robusta para la vigilancia de reas amplias y para el seguimiento de objetivos. Cuando el movimiento de dichos objetivos es suficientemente suave, no tiene cambios bruscos de trayectoria, el algoritmo ClusterTrack proporciona un rendimiento excelente en trminos de identificacin y seguimiento de trayectorias los objetos designados como blancos. Este algoritmo podra, por supuesto, ser utilizado para numerosas aplicaciones y se podra seguir esta lnea de trabajo para futuras investigaciones. No es sorprendente que las redes de sensores de binarios de proximidad hayan atrado mucha atencin ltimamente ya que, a pesar de la informacin mnima de un sensor de proximidad binario proporciona, las redes de este tipo pueden realizar un seguimiento de todo tipo de objetivos con la precisin suficiente. Abstract The increasing interest in wireless sensor networks can be promptly understood simply by thinking about what they essentially are: a large number of small sensing self-powered nodes which gather information or detect special events and communicate in a wireless fashion, with the end goal of handing their processed data to a base station. The sensor nodes are densely deployed inside the phenomenon, they deploy random and have cooperative capabilities. Usually these devices are small and inexpensive, so that they can be produced and deployed in large numbers, and so their resources in terms of energy, memory, computational speed and bandwidth are severely constrained. Sensing, processing and communication are three key elements whose combination in one tiny device gives rise to a vast number of applications. Sensor networks provide endless opportunities, but at the same time pose formidable challenges, such as the fact that energy is a scarce and usually non-renewable resource. However, recent advances in low power Very Large Scale Integration, embedded computing, communication hardware, and in general, the convergence of computing and communications, are making this emerging technology a reality. Likewise, advances in nanotechnology and Micro Electro-Mechanical Systems are pushing toward networks of tiny distributed sensors and actuators. There are different sensors such as pressure, accelerometer, camera, thermal, and microphone. They monitor conditions at different locations, such as temperature, humidity, vehicular movement, lightning condition, pressure, soil makeup, noise levels, the presence or absence of certain kinds of objects, mechanical stress levels on attached objects, the current characteristics such as speed, direction and size of an object, etc. The state of Wireless Sensor Networks will be checked and the most famous protocols reviewed. As Radio Frequency Identification (RFID) is becoming extremely present and important nowadays, it will be examined as well. RFID has a crucial role to play in business and for individuals alike going forward. The impact of wireless identification is exerting strong pressures in RFID technology and services research and development, standards development, security compliance and privacy, and many more. The economic value is proven in some countries while others are just on the verge of planning or in pilot stages, but the wider spread of usage has yet to take hold or unfold through the modernisation of business models and applications. Possible applications of sensor networks are of interest to the most diverse fields. Environmental monitoring, warfare, child education, surveillance, micro-surgery, and agriculture are only a few examples. Some real hardware applications in the United States of America will be checked as it is probably the country that has investigated most in this area. Universities like Berkeley, UCLA (University of California, Los Angeles) Harvard and enterprises such as Intel are leading those investigations. But not just USA has been using and investigating wireless sensor networks. University of Southampton e.g. is to develop technology to monitor glacier behaviour using sensor networks contributing to fundamental research in glaciology and wireless sensor networks. Coalesenses GmbH (Germany) and ETH Zurich are working in applying wireless sensor networks in many different areas too. A Spanish solution will be the one examined more thoroughly for being innovative, adaptable and multipurpose. This study of the sensor has been focused mainly to traffic applications but it cannot be forgotten the more than 50 different application compilation that has been published by this specific sensors firm. Currently there are many vehicle surveillance technologies including loop sensors, video cameras, image sensors, infrared sensors, microwave radar, GPS, etc. The performance is acceptable but not sufficient because of their limited coverage and expensive costs of implementation and maintenance, specially the last one. They have defects such as: line-ofsight, low exactness, depending on environment and weather, cannot perform no-stop work whether daytime or night, high costs for installation and maintenance, etc. Consequently, in actual traffic applications the received data is insufficient or bad in terms of real-time owed to detector quantity and cost. With the increase of vehicle in urban road networks, the vehicle detection technologies are confronted with new requirements. Wireless sensor network is the state of the art technology and a revolution in remote information sensing and collection applications. It has broad prospect of application in intelligent transportation system. An application for target tracking and counting using a network of binary sensors has been developed. This would allow the appliance to spend much less energy when transmitting information and to make more independent devices in order to have a better traffic control. The application is focused on the efficacy of collaborative tracking rather than on the communication protocols used by the sensor nodes. Holiday crowds are a good case in which it is necessary to keep count of the cars on the roads. To this end a Matlab simulation has been produced for target tracking and counting using a network of binary sensors that e.g. could be implemented in Libeliums solution. Libelium is the enterprise that has developed the sensor that will be deeply examined. This would allow the appliance to spend much less energy when transmitting information and to make more independent devices. The promising results obtained indicate that binary proximity sensors can form the basis for a robust architecture for wide area surveillance and tracking. When the target paths are smooth enough ClusterTrack particle filter algorithm gives excellent performance in terms of identifying and tracking different target trajectories. This algorithm could, of course, be used for different applications and that could be done in future researches. It is not surprising that binary proximity sensor networks have attracted a lot of attention lately. Despite the minimal information a binary proximity sensor provides, networks of these sensing modalities can track all kinds of different targets classes accurate enough.
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Memory analysis techniques have become sophisticated enough to model, with a high degree of accuracy, the manipulation of simple memory structures (finite structures, single/double linked lists and trees). However, modern programming languages provide extensive library support including a wide range of generic collection objects that make use of complex internal data structures. While these data structures ensure that the collections are efficient, often these representations cannot be effectively modeled by existing methods (either due to excessive analysis runtime or due to the inability to represent the required information). This paper presents a method to represent collections using an abstraction of their semantics. The construction of the abstract semantics for the collection objects is done in a manner that allows individual elements in the collections to be identified. Our construction also supports iterators over the collections and is able to model the position of the iterators with respect to the elements in the collection. By ordering the contents of the collection based on the iterator position, the model can represent a notion of progress when iteratively manipulating the contents of a collection. These features allow strong updates to the individual elements in the collection as well as strong updates over the collections themselves.
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Modeling the evolution of the state of program memory during program execution is critical to many parallehzation techniques. Current memory analysis techniques either provide very accurate information but run prohibitively slowly or produce very conservative results. An approach based on abstract interpretation is presented for analyzing programs at compile time, which can accurately determine many important program properties such as aliasing, logical data structures and shape. These properties are known to be critical for transforming a single threaded program into a versin that can be run on mltiple execution units in parallel. The analysis is shown to be of polynomial complexity in the size of the memory heap. Experimental results for benchmarks in the Jolden suite are given. These results show that in practice the analysis method is efflcient and is capable of accurately determining shape information in programs that crate and maniplate complex data structures.
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This paper seeks to analyze the political dimension of the body, and consequently the inherently political dimension of space, through the instrumental notion of situation, understood as an spatio-temporal mesh configured by bodies, practices and discourses. The political understood as the potential for action (or non-action) underlying the individual body, implies a renewed definition of a landscape that results from the bodys doing. Landscape becomes a multiple corporeality, a field of relations in which we discover ourselves enmeshed, not just placed; a field in which the limit is not frontier but bond and common dimension. A disquieting ambiguous zone appears there where the individual spatiality is born out of the body through the actualization of its political potential and entangles with others to constitute a common spatiality, political action of the multitude. The article is organized through the description of a back-and-forth movement between the revolts of Tehran in 2009 and the Iranian revolution of 1979. Also, a detour into the works of Robert Morris and Trisha Brown is required in order to understand the link between the body and the constitution of a common spatiality.
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The Caribbean and Central America are among the regions with highest HIV-1B prevalence worldwide. Despite of this high virus burden, little is known about the timing and the migration patterns of HIV-1B in these regions. Migration is one of the major processes shaping the genetic structure of virus populations. Thus, reconstruction of epidemiological network may contribute to understand HIV-1B evolution and reduce virus prevalence. We have investigated the spatio-temporal dynamics of the HIV-1B epidemic in The Caribbean and Central America using 1,610 HIV-1B partial pol sequences from 13 Caribbean and 5 Central American countries. Timing of HIV-1B introduction and virus evolutionary rates, as well as the spatial genetic structure of the HIV-1B populations and the virus migration patterns were inferred. Results revealed that in The Caribbean and Central America most of the HIV-1B variability was generated since the 80 s. At odds with previous data suggesting that Haiti was the origin of the epidemic in The Caribbean, our reconstruction indicated that the virus could have been disseminated from Puerto Rico and Antigua. These two countries connected two distinguishable migration areas corresponding to the (mainly Spanish-colonized) Easter and (mainly British-colonized) Western islands, which indicates that virus migration patterns are determined by geographical barriers and by the movement of human populations among culturally related countries. Similar factors shaped the migration of HIV-1B in Central America. The HIV-1B population was significantly structured according to the country of origin, and the genetic diversity in each country was associated with the virus prevalence in both regions, which suggests that virus populations evolve mainly through genetic drift. Thus, our work contributes to the understanding of HIV-1B evolution and dispersion pattern in the Americas, and its relationship with the geography of the area and the movements of human populations.
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Animal models and human functional imaging data implicate the dopamine system in mediating enhanced encoding of novel stimuli into human memory. A separate line of investigation suggests an association between a functional polymorphism in the promoter region for the human dopamine 4 receptor gene (DRD4) and sensitivity to novelty. We demonstrate, in two independent samples, that the -521Cmayor queT DRD4 promoter polymorphism determines the magnitude of human memory enhancement for contextually novel, perceptual oddball stimuli in an allele dose-dependent manner. The genotype-dependent memory enhancement conferred by the C allele is associated with increased neuronal responses during successful encoding of perceptual oddballs in the ventral striatum, an effect which is again allele dose-dependent. Furthermore, with repeated presentations of oddball stimuli, this memory advantage decreases, an effect mirrored by adaptation of activation in the hippocampus and substantia nigra/ventral tegmental area in C carriers only. Thus, a dynamic modulation of human memory enhancement for perceptually salient stimuli is associated with activation of a dopaminergic-hippocampal system, which is critically dependent on a functional polymorphism in the DRD4 promoter region.
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Los tipos de datos concurrentes son implementaciones concurrentes de las abstracciones de datos clsicas, con la diferencia de que han sido especficamente diseados para aprovechar el gran paralelismo disponible en las modernas arquitecturas multiprocesador y multincleo. La correcta manipulacin de los tipos de datos concurrentes resulta esencial para demostrar la completa correccin de los sistemas de software que los utilizan. Una de las mayores dificultades a la hora de disear y verificar tipos de datos concurrentes surge de la necesidad de tener que razonar acerca de un nmero arbitrario de procesos que invocan estos tipos de datos de manera concurrente. Esto requiere considerar sistemas parametrizados. En este trabajo estudiamos la verificacin formal de propiedades temporales de sistemas concurrentes parametrizados, poniendo especial nfasis en programas que manipulan estructuras de datos concurrentes. La principal dificultad a la hora de razonar acerca de sistemas concurrentes parametrizados proviene de la interaccin entre el gran nivel de concurrencia que stos poseen y la necesidad de razonar al mismo tiempo acerca de la memoria dinmica. La verificacin de sistemas parametrizados resulta en s un problema desafiante debido a que requiere razonar acerca de estructuras de datos complejas que son accedidas y modificadas por un numero ilimitado de procesos que manipulan de manera simultnea el contenido de la memoria dinmica empleando mtodos de sincronizacin poco estructurados. En este trabajo, presentamos un marco formal basado en mtodos deductivos capaz de ocuparse de la verificacin de propiedades de safety y liveness de sistemas concurrentes parametrizados que manejan estructuras de datos complejas. Nuestro marco formal incluye reglas de prueba y tcnicas especialmente adaptadas para sistemas parametrizados, las cuales trabajan en colaboracin con procedimientos de decisin especialmente diseados para analizar complejas estructuras de datos concurrentes. Un aspecto novedoso de nuestro marco formal es que efecta una clara diferenciacin entre el anlisis del flujo de control del programa y el anlisis de los datos que se manejan. El flujo de control del programa se analiza utilizando reglas de prueba y tcnicas de verificacin deductivas especialmente diseadas para lidiar con sistemas parametrizados. Comenzando a partir de un programa concurrente y la especificacin de una propiedad temporal, nuestras tcnicas deductivas son capaces de generar un conjunto finito de condiciones de verificacin cuya validez implican la satisfaccin de dicha especificacin temporal por parte de cualquier sistema, sin importar el nmero de procesos que formen parte del sistema. Las condiciones de verificacin generadas se corresponden con los datos manipulados. Estudiamos el diseo de procedimientos de decisin especializados capaces de lidiar con estas condiciones de verificacin de manera completamente automtica. Investigamos teoras decidibles capaces de describir propiedades de tipos de datos complejos que manipulan punteros, tales como implementaciones imperativas de pilas, colas, listas y skiplists. Para cada una de estas teoras presentamos un procedimiento de decisin y una implementacin prctica construida sobre SMT solvers. Estos procedimientos de decisin son finalmente utilizados para verificar de manera automtica las condiciones de verificacin generadas por nuestras tcnicas de verificacin parametrizada. Para concluir, demostramos como utilizando nuestro marco formal es posible probar no solo propiedades de safety sino adems de liveness en algunas versiones de protocolos de exclusin mutua y programas que manipulan estructuras de datos concurrentes. El enfoque que presentamos en este trabajo resulta ser muy general y puede ser aplicado para verificar un amplio rango de tipos de datos concurrentes similares. Abstract Concurrent data types are concurrent implementations of classical data abstractions, specifically designed to exploit the great deal of parallelism available in modern multiprocessor and multi-core architectures. The correct manipulation of concurrent data types is essential for the overall correctness of the software system built using them. A major difficulty in designing and verifying concurrent data types arises by the need to reason about any number of threads invoking the data type simultaneously, which requires considering parametrized systems. In this work we study the formal verification of temporal properties of parametrized concurrent systems, with a special focus on programs that manipulate concurrent data structures. The main difficulty to reason about concurrent parametrized systems comes from the combination of their inherently high concurrency and the manipulation of dynamic memory. This parametrized verification problem is very challenging, because it requires to reason about complex concurrent data structures being accessed and modified by threads which simultaneously manipulate the heap using unstructured synchronization methods. In this work, we present a formal framework based on deductive methods which is capable of dealing with the verification of safety and liveness properties of concurrent parametrized systems that manipulate complex data structures. Our framework includes special proof rules and techniques adapted for parametrized systems which work in collaboration with specialized decision procedures for complex data structures. A novel aspect of our framework is that it cleanly differentiates the analysis of the program control flow from the analysis of the data being manipulated. The program control flow is analyzed using deductive proof rules and verification techniques specifically designed for coping with parametrized systems. Starting from a concurrent program and a temporal specification, our techniques generate a finite collection of verification conditions whose validity entails the satisfaction of the temporal specification by any client system, in spite of the number of threads. The verification conditions correspond to the data manipulation. We study the design of specialized decision procedures to deal with these verification conditions fully automatically. We investigate decidable theories capable of describing rich properties of complex pointer based data types such as stacks, queues, lists and skiplists. For each of these theories we present a decision procedure, and its practical implementation on top of existing SMT solvers. These decision procedures are ultimately used for automatically verifying the verification conditions generated by our specialized parametrized verification techniques. Finally, we show how using our framework it is possible to prove not only safety but also liveness properties of concurrent versions of some mutual exclusion protocols and programs that manipulate concurrent data structures. The approach we present in this work is very general, and can be applied to verify a wide range of similar concurrent data types.