905 resultados para manner in which discretion to be exercised


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Using data from a self-administered survey of 1,017 households we assess the long-term impact of establishing a special economic zone, on those who are exogenously selected to be displaced. We find those who are displaced suffer from lower land compensation and lack of adequate property rights. There is also some evidence of lower labour market participation among those who are displaced. However, in the long term, across measurable welfare indicators, we do not find that displaced households are significantly different from other households. One source of this resilience is through employment at the special economic zone – which is higher among displaced households compared to other households. Another factor that contributed to the absence of differences is spill-over effects; which made access to employment, education and other facilities about homogenous across displaced and non-displaced households.

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This paper introduces the experience of using videoconferencing and recording as a mechanism to support courses which need to be promoted or discontinued within the framework of the European convergence process. Our objective is to make these courses accessible as live streaming during the lessons as well as recorded lectures and associated documents available to the students as soon as the lesson has finished. The technology used has been developed in our university and it is all open source. Although this is a technical project the key is the human factor involved. The people managing the virtual sessions are students of the courses being recorded. However, they lack technical knowledge, so we had to train them in audiovisuals and enhance the usability of the videoconferencing tool and platform. The validation process is being carried out in five real scenarios at our university. During the whole period we are evaluating technical and pedagogical issues of this experience for both students and teachers to guide the future development of the service. Depending on the final results, the service of lectures recording will be available as educational resource for all of the teaching staff of our university.

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The art of construction is a risky activity that directly affects the life and physical integrity of persons. Since the approval of Law 31/1995, of November 8, Prevention of Occupational Risks was the first legislation that established the current basis in all sectors and then transposed into Spanish law Directive 92/57/CEE called Royal Decree 1627/1997 of October 24, on minimum safety and health dispositions in construction works, measures have been proposed to develop a mixed body of scientific literature composed of researchers and professionals in the field of occupational safety and health, but even today there is still no clear and firm proposal, showing a lack of awareness in the occupational risk prevention and, therefore, a consolidation of the culture of prevention in society. Therefore, the technicians, who make up the building process, can incur in very high responsibilities, such as: Author of the project, Coordinator of Safety and Health during the preparation of the project and during the execution of works, Site Management: Site Manager. This involves the immediate creation of a general training in prevention for all architects starting when still studying, as well as specific training, appropriate and complementary to all the architects that will be devoted to the specialty of occupational safety and health in construction works. That is, first, we must make the responsible bodies aware of the urgent need to integrate risk prevention in the curricula of architecture and later in the continuing education of the profession. It is necessary that our teaching must conform to the laws on safety and health, due to the fact that the law recognizes our academic degrees and professional qualifications to perform functions in that area

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Carbon distribution in the stem of 2-year-old cork oak plants was studied by 14CO2 pulse labeling in late spring in order to trace the allocation of photoassimilates to tissue and biochemical stem components of cork oak. The fate of 14C photoassimilated carbon was followed during two periods: the first 72 h (short-term study) and the first 52 weeks (long-term study) after the 14CO2 photosynthetic assimilation. The results showed that 14C allocation to stem tissues was dependent on the time passed since photoassimilation and on the season of the year. In the first 3 h all 14C was found in the polar extractives. After 3 h, it started to be allocated to other stem fractions. In 1 day, 14C was allocated mostly to vascular cambium and, to a lesser extent, to primary phloem; no presence of 14C was recorded for the periderm. However, translocation of 14C to phellem was observed from 1 week after 14CO2 pulse labeling. The phellogen was not completely active in its entire circumference at labeling, unlike the vascular cambium; this was the tissue that accumulated most photoassimilated 14C at the earliest sampling. The fraction of leaf-assimilated 14C that was used by the stem peaked at 57% 1 week after 14CO2 plant exposure. The time lag between C photoassimilation and suberin accumulation was ∼8 h, but the most active period for suberin accumulation was between 3 and 7 days. Suberin, which represented only 1.77% of the stem weight, acted as a highly effective sink for the carbon photoassimilated in late spring since suberin specific radioactivity was much higher than for any other stem component as early as only 1 week after 14C plant labeling. This trend was maintained throughout the whole experiment. The examination of microautoradiographs taken over 1 year provided a new method for quantifying xylem growth. Using this approach it was found that there was more secondary xylem growth in late spring than in other times of the year, because the calculated average cell division time was much shorter.

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Nuestro cerebro contiene cerca de 1014 sinapsis neuronales. Esta enorme cantidad de conexiones proporciona un entorno ideal donde distintos grupos de neuronas se sincronizan transitoriamente para provocar la aparición de funciones cognitivas, como la percepción, el aprendizaje o el pensamiento. Comprender la organización de esta compleja red cerebral en base a datos neurofisiológicos, representa uno de los desafíos más importantes y emocionantes en el campo de la neurociencia. Se han propuesto recientemente varias medidas para evaluar cómo se comunican las diferentes partes del cerebro a diversas escalas (células individuales, columnas corticales, o áreas cerebrales). Podemos clasificarlos, según su simetría, en dos grupos: por una parte, la medidas simétricas, como la correlación, la coherencia o la sincronización de fase, que evalúan la conectividad funcional (FC); mientras que las medidas asimétricas, como la causalidad de Granger o transferencia de entropía, son capaces de detectar la dirección de la interacción, lo que denominamos conectividad efectiva (EC). En la neurociencia moderna ha aumentado el interés por el estudio de las redes funcionales cerebrales, en gran medida debido a la aparición de estos nuevos algoritmos que permiten analizar la interdependencia entre señales temporales, además de la emergente teoría de redes complejas y la introducción de técnicas novedosas, como la magnetoencefalografía (MEG), para registrar datos neurofisiológicos con gran resolución. Sin embargo, nos hallamos ante un campo novedoso que presenta aun varias cuestiones metodológicas sin resolver, algunas de las cuales trataran de abordarse en esta tesis. En primer lugar, el creciente número de aproximaciones para determinar la existencia de FC/EC entre dos o más señales temporales, junto con la complejidad matemática de las herramientas de análisis, hacen deseable organizarlas todas en un paquete software intuitivo y fácil de usar. Aquí presento HERMES (http://hermes.ctb.upm.es), una toolbox en MatlabR, diseñada precisamente con este fin. Creo que esta herramienta será de gran ayuda para todos aquellos investigadores que trabajen en el campo emergente del análisis de conectividad cerebral y supondrá un gran valor para la comunidad científica. La segunda cuestión practica que se aborda es el estudio de la sensibilidad a las fuentes cerebrales profundas a través de dos tipos de sensores MEG: gradiómetros planares y magnetómetros, esta aproximación además se combina con un enfoque metodológico, utilizando dos índices de sincronización de fase: phase locking value (PLV) y phase lag index (PLI), este ultimo menos sensible a efecto la conducción volumen. Por lo tanto, se compara su comportamiento al estudiar las redes cerebrales, obteniendo que magnetómetros y PLV presentan, respectivamente, redes más densamente conectadas que gradiómetros planares y PLI, por los valores artificiales que crea el problema de la conducción de volumen. Sin embargo, cuando se trata de caracterizar redes epilépticas, el PLV ofrece mejores resultados, debido a la gran dispersión de las redes obtenidas con PLI. El análisis de redes complejas ha proporcionado nuevos conceptos que mejoran caracterización de la interacción de sistemas dinámicos. Se considera que una red está compuesta por nodos, que simbolizan sistemas, cuyas interacciones se representan por enlaces, y su comportamiento y topología puede caracterizarse por un elevado número de medidas. Existe evidencia teórica y empírica de que muchas de ellas están fuertemente correlacionadas entre sí. Por lo tanto, se ha conseguido seleccionar un pequeño grupo que caracteriza eficazmente estas redes, y condensa la información redundante. Para el análisis de redes funcionales, la selección de un umbral adecuado para decidir si un determinado valor de conectividad de la matriz de FC es significativo y debe ser incluido para un análisis posterior, se convierte en un paso crucial. En esta tesis, se han obtenido resultados más precisos al utilizar un test de subrogadas, basado en los datos, para evaluar individualmente cada uno de los enlaces, que al establecer a priori un umbral fijo para la densidad de conexiones. Finalmente, todas estas cuestiones se han aplicado al estudio de la epilepsia, caso práctico en el que se analizan las redes funcionales MEG, en estado de reposo, de dos grupos de pacientes epilépticos (generalizada idiopática y focal frontal) en comparación con sujetos control sanos. La epilepsia es uno de los trastornos neurológicos más comunes, con más de 55 millones de afectados en el mundo. Esta enfermedad se caracteriza por la predisposición a generar ataques epilépticos de actividad neuronal anormal y excesiva o bien síncrona, y por tanto, es el escenario perfecto para este tipo de análisis al tiempo que presenta un gran interés tanto desde el punto de vista clínico como de investigación. Los resultados manifiestan alteraciones especificas en la conectividad y un cambio en la topología de las redes en cerebros epilépticos, desplazando la importancia del ‘foco’ a la ‘red’, enfoque que va adquiriendo relevancia en las investigaciones recientes sobre epilepsia. ABSTRACT There are about 1014 neuronal synapses in the human brain. This huge number of connections provides the substrate for neuronal ensembles to become transiently synchronized, producing the emergence of cognitive functions such as perception, learning or thinking. Understanding the complex brain network organization on the basis of neuroimaging data represents one of the most important and exciting challenges for systems neuroscience. Several measures have been recently proposed to evaluate at various scales (single cells, cortical columns, or brain areas) how the different parts of the brain communicate. We can classify them, according to their symmetry, into two groups: symmetric measures, such as correlation, coherence or phase synchronization indexes, evaluate functional connectivity (FC); and on the other hand, the asymmetric ones, such as Granger causality or transfer entropy, are able to detect effective connectivity (EC) revealing the direction of the interaction. In modern neurosciences, the interest in functional brain networks has increased strongly with the onset of new algorithms to study interdependence between time series, the advent of modern complex network theory and the introduction of powerful techniques to record neurophysiological data, such as magnetoencephalography (MEG). However, when analyzing neurophysiological data with this approach several questions arise. In this thesis, I intend to tackle some of the practical open problems in the field. First of all, the increase in the number of time series analysis algorithms to study brain FC/EC, along with their mathematical complexity, creates the necessity of arranging them into a single, unified toolbox that allow neuroscientists, neurophysiologists and researchers from related fields to easily access and make use of them. I developed such a toolbox for this aim, it is named HERMES (http://hermes.ctb.upm.es), and encompasses several of the most common indexes for the assessment of FC and EC running for MatlabR environment. I believe that this toolbox will be very helpful to all the researchers working in the emerging field of brain connectivity analysis and will entail a great value for the scientific community. The second important practical issue tackled in this thesis is the evaluation of the sensitivity to deep brain sources of two different MEG sensors: planar gradiometers and magnetometers, in combination with the related methodological approach, using two phase synchronization indexes: phase locking value (PLV) y phase lag index (PLI), the latter one being less sensitive to volume conduction effect. Thus, I compared their performance when studying brain networks, obtaining that magnetometer sensors and PLV presented higher artificial values as compared with planar gradiometers and PLI respectively. However, when it came to characterize epileptic networks it was the PLV which gives better results, as PLI FC networks where very sparse. Complex network analysis has provided new concepts which improved characterization of interacting dynamical systems. With this background, networks could be considered composed of nodes, symbolizing systems, whose interactions with each other are represented by edges. A growing number of network measures is been applied in network analysis. However, there is theoretical and empirical evidence that many of these indexes are strongly correlated with each other. Therefore, in this thesis I reduced them to a small set, which could more efficiently characterize networks. Within this framework, selecting an appropriate threshold to decide whether a certain connectivity value of the FC matrix is significant and should be included in the network analysis becomes a crucial step, in this thesis, I used the surrogate data tests to make an individual data-driven evaluation of each of the edges significance and confirmed more accurate results than when just setting to a fixed value the density of connections. All these methodologies were applied to the study of epilepsy, analysing resting state MEG functional networks, in two groups of epileptic patients (generalized and focal epilepsy) that were compared to matching control subjects. Epilepsy is one of the most common neurological disorders, with more than 55 million people affected worldwide, characterized by its predisposition to generate epileptic seizures of abnormal excessive or synchronous neuronal activity, and thus, this scenario and analysis, present a great interest from both the clinical and the research perspective. Results revealed specific disruptions in connectivity and network topology and evidenced that networks’ topology is changed in epileptic brains, supporting the shift from ‘focus’ to ‘networks’ which is gaining importance in modern epilepsy research.

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Jóvenes Nucleares (Spanish Young Generation in Nuclear, JJNN) is a non-profit organization that depends on the Spanish Nuclear Society (SNE). The Universidad Politécnica de Madrid (Technical University of Madrid, UPM) was chosen to host the Seminar as it is one of the most prestigious technical universities of Spain, and has a very strong curriculum in nuclear engineering training and research. Both, the UPM and the SNE, supported strongly the seminar: the opening session was conducted by the member of to board of directors of the Spanish Nuclear Society and Nuclear Engineering professor of the UPM, Emilio Mínguez and the closing session was conducted by the director of the Nuclear Fusion Institute (UPM).

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After the extensive research on the capabilities of the Boundary Integral Equation Method produced during the past years the versatility of its applications has been well founded. Maybe the years to come will see the in-depth analysis of several conflictive points, for example, adaptive integration, solution of the system of equations, etc. This line is clear in academic research. In this paper we comment on the incidence of the manner of imposing the boundary conditions in 3-D coupled problems. Here the effects are particularly magnified: in the first place by the simple model used (constant elements) and secondly by the process of solution, i.e. first a potential problem is solved and then the results are used as data for an elasticity problem. The errors add to both processes and small disturbances, unimportant in separated problems, can produce serious errors in the final results. The specific problem we have chosen is especially interesting. Although more general cases (i.e. transient)can be treated, here the domain integrals can be converted into boundary ones and the influence of the manner in which boundary conditions are applied will reflect the whole importance of the problem.

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Featured Speaker

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Peer reviewed

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Asparaginyl-tRNA (Asn-tRNA) and glutaminyl-tRNA (Gln-tRNA) are essential components of protein synthesis. They can be formed by direct acylation by asparaginyl-tRNA synthetase (AsnRS) or glutaminyl-tRNA synthetase (GlnRS). The alternative route involves transamidation of incorrectly charged tRNA. Examination of the preliminary genomic sequence of the radiation-resistant bacterium Deinococcus radiodurans suggests the presence of both direct and indirect routes of Asn-tRNA and Gln-tRNA formation. Biochemical experiments demonstrate the presence of AsnRS and GlnRS, as well as glutamyl-tRNA synthetase (GluRS), a discriminating and a nondiscriminating aspartyl-tRNA synthetase (AspRS). Moreover, both Gln-tRNA and Asn-tRNA transamidation activities are present. Surprisingly, they are catalyzed by a single enzyme encoded by three ORFs orthologous to Bacillus subtilis gatCAB. However, the transamidation route to Gln-tRNA formation is idled by the inability of the discriminating D. radiodurans GluRS to produce the required mischarged Glu-tRNAGln substrate. The presence of apparently redundant complete routes to Asn-tRNA formation, combined with the absence from the D. radiodurans genome of genes encoding tRNA-independent asparagine synthetase and the lack of this enzyme in D. radiodurans extracts, suggests that the gatCAB genes may be responsible for biosynthesis of asparagine in this asparagine prototroph.

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It is clear that the initial analysis of visual motion takes place in the striate cortex, where directionally selective cells are found that respond to local motion in one direction but not in the opposite direction. Widely accepted motion models postulate as inputs to directional units two or more cells whose spatio-temporal receptive fields (RFs) are approximately 90° out of phase (quadrature) in space and in time. Simple cells in macaque striate cortex differ in their spatial phases, but evidence is lacking for the varying time delays required for two inputs to be in temporal quadrature. We examined the space-time RF structure of cells in macaque striate cortex and found two subpopulations of (nondirectional) simple cells, some that show strongly biphasic temporal responses, and others that are weakly biphasic if at all. The temporal impulse responses of these two classes of cells are very close to 90° apart, with the strongly biphasic cells having a shorter latency than the weakly biphasic cells. A principal component analysis of the spatio-temporal RFs of directionally selective simple cells shows that their RFs could be produced by a linear combination of two components; these two components correspond closely in their respective latencies and biphasic characters to those of strongly biphasic and weakly biphasic nondirectional simple cells, respectively. This finding suggests that the motion system might acquire the requisite temporal quadrature by combining inputs from these two classes of nondirectional cells (or from their respective lateral geniculate inputs, which appear to be from magno and parvo lateral geniculate cells, respectively).

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Contact of cultured mammary epithelial cells with the basement membrane protein laminin induces multiple responses, including cell shape changes, growth arrest, and, in the presence of prolactin, transcription of the milk protein β-casein. We sought to identify the specific laminin receptor(s) mediating the multiple cell responses to laminin. Using assays with clonal mammary epithelial cells, we reveal distinct functions for the α6β4 integrin, β1 integrins, and an E3 laminin receptor. Signals from laminin for β-casein expression were inhibited in the presence of function-blocking antibodies against both the α6 and β1 integrin subunits and by the laminin E3 fragment. The α6-blocking antibody perturbed signals mediated by the α6β4 integrin, and the β1-blocking antibody perturbed signals mediated by another integrin, the α subunit(s) of which remains to be determined. Neither α6- nor β1-blocking antibodies perturbed the cell shape changes resulting from cell exposure to laminin. However, the E3 laminin fragment and heparin both inhibited cell shape changes induced by laminin, thereby implicating an E3 laminin receptor in this function. These results elucidate the multiplicity of cell-extracellular matrix interactions required to integrate cell structure and signaling and ultimately permit normal cell function.

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Genetic analysis of limiting quantities of genomic DNA play an important role in DNA forensics, paleoarcheology, genetic disease diagnosis, genetic linkage analysis, and genetic diversity studies. We have tested the ability of degenerate oligonucleotide primed polymerase chain reaction (DOP-PCR) to amplify picogram quantities of human genomic DNA for the purpose of increasing the amount of template for genotyping with microsatellite repeat markers. DNA was uniformly amplified at a large number of typable loci throughout the human genome with starting template DNAs from as little as 15 pg to as much as 400 ng. A much greater-fold enrichment was seen for the smaller genomic DOP-PCRs. All markers tested were amplified from starting genomic DNAs in the range of 0.6–40 ng with amplifications of 200- to 600-fold. The DOP-PCR-amplified genomic DNA was an excellent and reliable template for genotyping with microsatellites, which give distinct bands with no increase in stutter artifact on di-, tri-, and tetranucleotide repeats. There appears to be equal amplification of genomic DNA from 55 of 55 tested discrete microsatellites implying near complete coverage of the human genome. Thus, DOP-PCR appears to allow unbiased, hundreds-fold whole genome amplification of human genomic DNA for genotypic analysis.

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Because ascorbic acid (AA) is concentrated in synaptic vesicles containing glutamic acid, we hypothesized that AA might act as a neurotransmitter. Because AA is an antioxidant, it might therefore inhibit nitric oxidergic (NOergic) activation of luteinizing hormone-releasing hormone (LH-RH) release from medial basal hypothalamic explants by chemically reducing NO. Cell membrane depolarization induced by increased potassium concentration [K+] increased medium concentrations of both AA and LH-RH. An inhibitor of NO synthase (NOS), NG-monomethyl-l-arginine (NMMA), prevented the increase in medium concentrations of AA and LH-RH induced by high [K+], suggesting that NO mediates release of both AA and LH-RH. Calcium-free medium blocked not only the increase in AA in the medium but also the release of LH-RH. Sodium nitroprusside, which releases NO, stimulated LH-RH release and decreased the concentration of AA in the incubation medium, presumably because the NO released oxidized AA to dehydro-AA. AA (10−5 to 10−3 M) had no effect on basal LH-RH release but completely blocked high [K+]- and nitroprusside-induced LH-RH release. N-Methyl-d-aspartic acid (NMDA), which mimics the action of the excitatory amino acid neurotransmitter glutamic acid, releases LH-RH by releasing NO. AA (10−5 to 10−3 M) inhibited the LH-RH-releasing action of NMDA. AA may be an inhibitory neurotransmitter that blocks NOergic stimulation of LH-RH release by chemically reducing the NO released by the NOergic neurons.