132 resultados para Puzzle difficulty


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Report for the scientific sojourn at the University of Reading, United Kingdom, from January until May 2008. The main objectives have been firstly to infer population structure and parameters in demographic models using a total of 13 microsatellite loci for genotyping approximately 30 individuals per population in 10 Palinurus elephas populations both from Mediterranean and Atlantic waters. Secondly, developing statistical methods to identify discrepant loci, possibly under selection and implement those methods using the R software environment. It is important to consider that the calculation of the probability distribution of the demographic and mutational parameters for a full genetic data set is numerically difficult for complex demographic history (Stephens 2003). The Approximate Bayesian Computation (ABC), based on summary statistics to infer posterior distributions of variable parameters without explicit likelihood calculations, can surmount this difficulty. This would allow to gather information on different demographic prior values (i.e. effective population sizes, migration rate, microsatellite mutation rate, mutational processes) and assay the sensitivity of inferences to demographic priors by assuming different priors.

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Investigación producida a partir de una estancia en la Université Paul Sabatier, Toulouse III - CNRS, entre 2007 y 2009. Durante los últimos años la investigación centrada en nuevos materiales de tamaño nanoscòpico (nanopartículas, quantum dots, nanotubos de carbono,...) ha experimentado un crecimiento considerable debido a las especiales propiedades de los "nanoobjetos" con respecto a magnetismo, catálisis, conductividad eléctrica, etc ... Sin embargo, hoy en día todavía existen pocas aplicaciones de las nanopartículas en temas medioambientales. Uno de los motivos de esta situación es la posible toxicidad de los nanoobjetos, pero existe también una dificultad tecnológica dado que las nanopartículas tienden a agregarse y es muy difícil manipularlas sin que pierdan sus propiedades especiales. Así, aunque la preparación de materiales catalíticos nanoestructurados es muy interesante, es necesario definir nuevas estrategias para prepararlos. Este proyecto de investigación tiene como objetivo principal la preparación de nuevas membranas catalíticas con nanopartículas metálicas en el interior para aplicaciones de tratamiento de agua. La innovación principal de este proyecto consiste en que las nanopartículas no son introducidas en la matriz polimérica una vez preformadas sino que se hacen crecer en el interior de la matriz polimérica mediante una síntesis intermatricial. El único requisito es que la matriz polimérica contenga grupos funcionales capaces de interaccionar con los precursores de las nanopartículas. Una vez finalizado el proyecto se puede afirmar que se han logrado parte de los objetivos planteados inicialmente. Concreamente ha quedado demostrado que se pueden sintetizar nanopartículas metálicas de metales nobles (platino y paladio) en membranas de fibra hueca de micro- y ultrafiltración siguiendo dos metodologías diferentes: modificación fotoquímica de polímeros y deposición de multicapas de polielectrolitos. Los nuevos materiales son efectivos en la catálisis de reducción de un compuesto modelo (4-nitrofenol con borohidruro de sodio) y, en general, los resultados han sido satisfactorios. Sin embargo, se ha puesto de manifiesto que el uso de un reactivo que genera hidrógeno gas en contacto con la solución acuosa dificulta enormemente la implementación de la reacción catalítica al ser el medio de la membrana una matriz porosa. Así, como conclusión principal se puede decir que se han encontrado las limitaciones de esta aproximación y se sugieren dos posibilidades de continuidad: la utilización de las membranas sintetizadas en contactores gas-líquido o bien el estudio y optimización del sistema de membrana en configuración de membranas planas, un objetivo más asequible dada su menor complejidad. Esta investigación se ha realizado en el seno del “Laboratoire de Génie Chimique” de Toulouse y del Departamento de Química de la Michigan State University y ha sido posible gracias a un proyecto financiado por la “Agence National pour la Recherce” y al programa PERMEANT entre el CNRS y la NSF.

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What allows an armed group in a civil war to prevent desertion? This paper addresses this question with a focus on control in the rearguard. Most past studies focus on motivations for desertion. They explain desertion in terms of where soldiers stand in relation to the macro themes of the war, or in terms of an inability to provide positive incentives to overcome the collective action problem. However, since individuals decide whether and how to participate in civil wars for multiple reasons, responding to a variety of local conditions in an environment of threat and violence, a focus only on macro-level motivations is incomplete. The opportunities side of the ledger deserves more attention. I therefore turn my attention to how control by an armed group eliminates soldiers’ opportunities to desert. In particular, I consider the control that an armed group maintains over soldiers’ hometowns, treating geographic terrain as an important exogenous indicator of the ease of control. Rough terrain at home affords soldiers and their families and friends advantages in ease of hiding, the difficulty of using force, and local knowledge. Based on an original dataset of soldiers from Santander Province in the Spanish Civil War, gathered from archival sources, I find statistical evidence that the rougher the terrain in a soldier’s home municipality, the more likely he is to desert. I find complementary qualitative evidence indicating that soldiers from rough-terrain communities took active advantage of their greater opportunities for evasion. This finding has important implications for the way observers interpret different soldiers’ decisions to desert or remain fighting, for the prospect that structural factors may shape the cohesion of armed groups, and for the possibility that local knowledge may be a double-edged sword, making soldiers simultaneously good at fighting and good at deserting.

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Creació d'un joc del tipus Arcade beat'em up en 2D utilitzant escenaris amb una certa profunditat de moviment i dotant als personatges no jugadors i altres objectes d'Intel·ligència Artificial de manera que el seu comportament no sigui sempre lineal i aprofitant-ho per afegir nivells de dificultat.

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Un dels conceptes que més discussions han suscitat en l'àmbit de la filosofia social i política en l'època moderna i contemporània és, sens dubte, el concepte d'utopia. La utopia té una gran complexitat a nivell semàntic, en la mesura que al·ludeix a un somni d'una vida millor ancorat en la imaginació, que no té cap possibilitat d'encarnar-se en la realitat concreta, o bé que és concebut com una categoria antropològica de valor singular, amb capacitat per conduir la humanitat vers la seva realització definitiva.

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El projecte es basa en desenvolupar una solució per a la integració dins de la plataforma Moodle, d'un formulari que permeti sol·licitar, als usuaris registrats, exercicis dels indicadors estadístics més comuns, i escollir-ne el nivell de dificultat. La creació dels exercicis i la solució dels mateixos, es durà a terme en el moment de la seva sol·licitud, a través d'un procediment automatitzat que generarà dades aleatòries dins d'un rang determinat. El procediment automatitzat es realitzarà mitjançant la funció "Sweave" del programari estadístic R. Aquesta funció integra en un únic document els continguts de text del programari LaTeX amb els continguts estadístics provinents de R.

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Consumer reviews, opinions and shared experiences in the use of a product is a powerful source of information about consumer preferences that can be used in recommender systems. Despite the importance and value of such information, there is no comprehensive mechanism that formalizes the opinions selection and retrieval process and the utilization of retrieved opinions due to the difficulty of extracting information from text data. In this paper, a new recommender system that is built on consumer product reviews is proposed. A prioritizing mechanism is developed for the system. The proposed approach is illustrated using the case study of a recommender system for digital cameras

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Process supervision is the activity focused on monitoring the process operation in order to deduce conditions to maintain the normality including when faults are present Depending on the number/distribution/heterogeneity of variables, behaviour situations, sub-processes, etc. from processes, human operators and engineers do not easily manipulate the information. This leads to the necessity of automation of supervision activities. Nevertheless, the difficulty to deal with the information complicates the design and development of software applications. We present an approach called "integrated supervision systems". It proposes multiple supervisors coordination to supervise multiple sub-processes whose interactions permit one to supervise the global process

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Aortic stiffness is an independent predictor factor for cardiovascular risk. Different methods for determining pulse wave velocity (PWV) are used, among which the most common are mechanical methods such as SphygmoCor or Complior, which require specific devices and are limited by technical difficulty in obtaining measurements. Doppler guided by 2D ultrasound is a good alternative to these methods. We studied 40 patients (29 male, aged 21 to 82 years) comparing the Complior method with Doppler. Agreement of both devices was high (R = 0.91, 0.84-0.95, 95% CI). The reproducibility analysis revealed no intra-nor interobserver differences. Based on these results, we conclude that Doppler ultrasound is a reliable and reproducible alternative to other established methods for themeasurement of aortic PWV

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This article provides an in-depth study of long-term female unemployment in Catalonia.Long-term unemployment statistics reveal which social groups are most likely to experience difficulty re-entering the labour market. In this case, we found that women are mainly affected by this type of labour exclusion, in particular poorly qualified, working-class women who are aged over 45 and with family responsibilities.The article aims to explore how the overlapping of factors such as gender, age, social class, origin and the division of work based on gender are related to long-term female unemployment. Moreover, we were able to detect which conceptual tools provide us with the production/reproduction paradigm so as to be able to analyse the future of female unemployment. The methodology we used combines quantitative and qualitative approaches. On the one hand, the analysis of secondary statistical data focusing on Catalonia is useful in understanding the situation from a macro-social perspective. On the other hand, an exploratory discussion group enables us to investigate social imaginary practises among unemployed working class women aged over 45. This discussion group was held in Igualada -capital of the Anoia region - an area of Catalonia deeply affected by unemployment in the current economic crisis.

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Genomic plasticity of human chromosome 8p23.1 region is highly influenced by two groups of complex segmental duplications (SDs), termed REPD and REPP, that mediate different kinds of rearrangements. Part of the difficulty to explain the wide range of phenotypes associated with 8p23.1 rearrangements is that REPP and REPD are not yet well characterized, probably due to their polymorphic status. Here, we describe a novel primate-specific gene family, named FAM90A (family with sequence similarity 90), found within these SDs. According to the current human reference sequence assembly, the FAM90A family includes 24 members along 8p23.1 region plus a single member on chromosome 12p13.31, showing copy number variation (CNV) between individuals. These genes can be classified into subfamilies I and II, which differ in their upstream and 5′-untranslated region sequences, but both share the same open reading frame and are ubiquitously expressed. Sequence analysis and comparative fluorescence in situ hybridization studies showed that FAM90A subfamily II suffered a big expansion in the hominoid lineage, whereas subfamily I members were likely generated sometime around the divergence of orangutan and African great apes by a fusion process. In addition, the analysis of the Ka/Ks ratios provides evidence of functional constraint of some FAM90A genes in all species. The characterization of the FAM90A gene family contributes to a better understanding of the structural polymorphism of the human 8p23.1 region and constitutes a good example of how SDs, CNVs and rearrangements within themselves can promote the formation of new gene sequences with potential functional consequences.

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The problem of jointly estimating the number, the identities, and the data of active users in a time-varying multiuser environment was examined in a companion paper (IEEE Trans. Information Theory, vol. 53, no. 9, September 2007), at whose core was the use of the theory of finite random sets on countable spaces. Here we extend that theory to encompass the more general problem of estimating unknown continuous parameters of the active-user signals. This problem is solved here by applying the theory of random finite sets constructed on hybrid spaces. We doso deriving Bayesian recursions that describe the evolution withtime of a posteriori densities of the unknown parameters and data.Unlike in the above cited paper, wherein one could evaluate theexact multiuser set posterior density, here the continuous-parameter Bayesian recursions do not admit closed-form expressions. To circumvent this difficulty, we develop numerical approximationsfor the receivers that are based on Sequential Monte Carlo (SMC)methods (“particle filtering”). Simulation results, referring to acode-divisin multiple-access (CDMA) system, are presented toillustrate the theory.

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Student guidance is an always desired characteristic in any educational system, butit represents special difficulty if it has to be deployed in an automated way to fulfilsuch needs in a computer supported educational tool. In this paper we explorepossible avenues relying on machine learning techniques, to be included in a nearfuture -in the form of a tutoring navigational tool- in a teleeducation platform -InterMediActor- currently under development. Since no data from that platform isavailable yet, the preliminary experiments presented in this paper are builtinterpreting every subject in the Telecommunications Degree at Universidad CarlosIII de Madrid as an aggregated macro-competence (following the methodologicalconsiderations in InterMediActor), such that marks achieved by students can beused as data for the models, to be replaced in a near future by real data directlymeasured inside InterMediActor. We evaluate the predictability of students qualifications, and we deploy a preventive early detection system -failure alert-, toidentify those students more prone to fail a certain subject such that correctivemeans can be deployed with sufficient anticipation.

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Aquesta comunicació presenta el projecte Aula de Tests desenvolupat com a suport en el desplegament de les assignatures de física i matemàtiques de primer curs dels estudis d'enginyeria de l’Escola Superior Politècnica de la Universitat Pompeu Fabra. El projecte té com a objectiu dissenyar eines d'auto aprenentatge i d'avaluació contínua accessible on-line a través de l'entorn Moodle per a afavorir el procés d'aprenentatge de l’estudiant. El context d’aquesta experiència es caracteritzaper la inherent dificultat dels estudis d’enginyeria, pel fet que molts estudiants entren a la universitat amb mancances substancials de coneixements en aquestes àrees així com la heterogeneïtat en quant a la formació pre-universitària. S’hi descriuen lescaracterístiques de les activitats programades i el context on s’han aplicat i es presenten els resultats de satisfacció, participació i notes que aporten informació útil al professorat per a adequar la planificació i les activitats els cursos següents.

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Conté: Camp David 2000; Jerusalén, el gran escollo; El desastre que Rabin quiso evitar; Lecciones de un pernicioso error; Doble filo del derecho al retorno; El dramático puzzle de Palestina; Los límites de un conflicto sin límites; Sharon y Arafat, símbolos de un fracaso; ¿La "hoja de ruta", papel mojado?; Quien siembra vientos…; Israel, puesto de prueba; El drama palestino; Israel-Palestina, pozo amargo; La violencia asimétrica israelí; Gaza, ciénaga y laberinto; En vez de muros, puentes