3,209 research outputs found

    New capabilities for Monte Carlo simulation of deuteron transport and secondary products generation

    Get PDF
    Several important research programs are dedicated to the development of facilities based on deuteron accelerators. In designing these facilities, the definition of a validated computational approach able to simulate deuteron transport and evaluate deuteron interactions and production of secondary particles with acceptable precision is a very important issue. Current Monte Carlo codes, such as MCNPX or PHITS, when applied for deuteron transport calculations use built-in semi-analytical models to describe deuteron interactions. These models are found unreliable in predicting neutron and photon generated by low energy deuterons, typically present in those facilities. We present a new computational tool, resulting from an extension of the MCNPX code, which improve significantly the treatment of problems where any secondary product (neutrons, photons, tritons, etc.) generated by low energy deuterons reactions could play a major role. Firstly, it handles deuteron evaluated data libraries, which allow describing better low deuteron energy interactions. Secondly, it includes a reduction variance technique for production of secondary particles by charged particle-induced nuclear interactions, which allow reducing drastically the computing time needed in transport and nuclear response calculations. Verification of the computational tool is successfully achieved. This tool can be very helpful in addressing design issues such as selection of the dedicated neutron production target and accelerator radioprotection analysis. It can be also helpful to test the deuteron cross-sections under development in the frame of different international nuclear data program

    Relevance of d-D interactions on neutron and tritium production in IFMIF-EVEDA accelerator prototype

    Full text link
    In the IFMIF-EVEDA accelerator prototype, deuterium is implanted in the components due to beam losses and in the beam dump, where the beam is stopped. The interaction of the deuterons with the deuterium previously implanted leads to the production of neutrons and tritium, which are important issues for radioprotection and safety analysis. A methodology to assess these production pathways in more realistic approach has been developed. The new tools and their main achievement are: (i) an “effective diffusivity coefficient” (deduced from available experimental data) that enables simulation of the diffusion phase, and (ii) the MCUNED code (able to handle deuteron transport libraries) allows to simulate the transport-slowdown of deuteron/tritium (to get the concentration profiles) and the neutron/tritium productions from d-Cu and d-D for up to 9 MeV incident deuteron. The results with/without theses tools are presented and their effect on the relevance of d-D sources versus d-Cu is evaluated

    Versatilidad del colgajo safeno para la cobertura de los defectos de rodilla: presentación de 6 casos

    Get PDF
    Clásicamente las pérdidas de sustancia de la rodilla se resuelven mediante injertos, colgajos cutáneos o fasciocutáneos, o bien por colgajos musculares de gemelo interno o externo, según la localización y profundidad del defecto. El propósito del trabajo es destacar la creciente relevancia de los colgajos neurovaseularizados como el colgajo safeno en la rodilla, en especial para aquellos casos sin gran componente infeccioso, en los que prevalecerían las indicaciones de utilización de colgajos musculares. Presentamos 4 casos de cobertura de prótesis de rodila expuestas en la región de la tuberosidad tibial anterior y/o línea de sutura y otros 2 casos de defectos tras resección tumoral. Los casos han sido realizados durante los 3 últimos años y su seguimiento clínico es de 6 meses a 3 años. En todos los casos se resolvió el problema de cobertura.Traditionally, substance loss at the knee level is solved through skin grafts, cutaneous or fascio-cutaneous flaps or through medial o lateral gastrocnemius muscle flaps depeding on the location and deep of the defect. We highlight the increasing relevance of neurovasculariccd flaps, and specially in this region, of the saphenous flap, better in cases with minor infectious component, in which the indication would be muscular flaps. We present four clinical cases in which we used them to cover anterior tibial tuberosity and/or dehiscent of skin closure and collected during the 3 last years another two cases with cutaneous defect after tumoral resection. All have uneventful recovery. The follow-up period varied from 6 months to 3 years

    Seeding approach to bubble nucleation in superheated Lennard-Jones fluids

    Get PDF
    We investigate vapor homogeneous nucleation in a superheated Lennard-Jones liquid with computer simulations. Special simulation techniques are required to address this study since the nucleation of a critical vapor bubble-one that has an equal chance to grow or shrink-in a moderately superheated liquid is a rare event. We use the Seeding method, which combines Classical Nucleation Theory with computer simulations of a liquid containing a vapor bubble to provide bubble nucleation rates in a wide temperature range. Seeding has been successfully applied to investigate the nucleation of crystals in supercooled fluids, and here we apply it to the liquid-to-vapor transition. We find that the Seeding method provides nucleation rates that are consistent with independent calculations not based on the assumptions of Classical Nucleation Theory. Different criteria to determine the radius of the critical bubble give different rate values. The accuracy of each criterion depends of the degree of superheating. Moreover, seeding simulations show that the surface tension depends on pressure for a given temperature. Therefore, using Classical Nucleation Theory with the coexistence surface tension does not provide good estimates of the nucleation rate

    High-pressure shift freezing : Recrystallization during storage

    Get PDF
    High-pressure shift freezing has been proposed as a method to produce frozen food with smaller ice crystal size and, consequently, with reduced tissular damage and higher overall quality. The fate of this initially improved crystal size distribution, decisive for the long-term value of this procedure, is unclear. The recrystallization behaviour of partially frozen aqueous solutions, as food models, is here compared with that of similar classically frozen samples. A microscopic observation cell has been specially designed for this purpose. The temporal evolution of high-pressure shift frozen ice crystals has been fitted to different mechanism models and is found to be similar within experimental error to that of classically frozen samples. However, differences in the shape evolution of crystals have been detected, which can be ascribed to small differences in the initial distribution. The implications of these observations for the long-term storage of frozen food are discussed.Centro de Investigación y Desarrollo en Criotecnología de Alimento

    The Spanish society of Parenteral and Enteral Nutrition (SENPE) and its relation with healthcare authorities

    Full text link
    Está muy bien documentado en la literatura médica que la desnutrición es un problema común en todos los niveles de atención sanitaria, desde atención primaria a especializada y en centros de atención geriátrica. Este problema no se limita a países con pocos recursos económicos o con limitado desarrollo social y económico. También es un problema universal en Europa. La desnutrición aumenta las cifras de morbilidad, mortalidad, ingresos hospitalarios y duración de la estancia. Estas cifras más elevadas suponen lógicamente un aumento del uso de recursos sanitarios. A pesar de esto, el problema de la desnutrición a menudo puede pasar desapercibido y el paciente no recibir el tratamiento necesario. Este problema requiere la cooperación de múltiples agentes tales como los Gobiernos de los Estados, los profesionales de la salud y los mismos ciudadanos. El VIII Foro de Debate concluye con la necesidad de establecer un claro plan de actuación (a semejanza de la European Alliance for Health Nutrition) y la creación de una plataforma (coalición) que reúna las voces de asociaciones de profesionales sanitarios, instituciones, colegios profesionales, asociaciones de pacientes, industria y entidades aseguradoras. Los fines de esta plataforma consistirán en informar de la extensión del problema, identificar y potenciar líderes que transmitan los fines de esta iniciativa ante las autoridades autonómicas y nacionales, propuesta de soluciones y colaboración en su puesta en marcha y finalmente, evaluación/ control de las acciones desarrolladasIt has been well documented in medical literature that hyponutrition is a common issue at all healthcare levels, from primary to specialized health care, as well as geria - tric healthcare facilities. This problem is not limited to countries with scarce economic resources or limited social development; it is also a universal issue in Europe. Hyponutrition increases the rates of morbidity, mortality, hospital admissions, and hospital stay. These higher figures also represent a higher use of healthcare resources. In spite of this, hyponutrition may often go undetected and the patient may not receive the necessary treatment. This problem requires the cooperation of multiple agents such as the Governments, the healthcare professionals, and the citizens themselves. The VIII Discussion Forum concludes on the need to establish a clear-cut plant for action (similar to the European Alliance for Health Nutrition) and the creation of a platform (coalition) encompassing the voices of healthcare professionals associations, institutions, professional colleges, patients associations, the pharmaceutical companies, and insurance companies. The goals of this platform will be to inform about the extent of this issue, to identity and promote leaders that will convey the aims of this initiative to regional and national healthcare authorities, to present solutions and to collaborate in their implementation, and finally to assess/control the actions take

    Additive Role of Immune System Infiltration and Angiogenesis in Uveal Melanoma Progression

    Get PDF
    Uveal melanoma (UM) is a malignant tumor that arises in the melanocytes of the uveal tract. It is the most frequent eye cancer, and despite new therapeutic approaches, prognosis is still poor, with up to 50% of patients developing metastasis with no efficient treatment options available. In contrast to cutaneous melanoma, UM is considered an "immune-cold" tumor due to the low mutational burden and the unique immunosuppressive microenvironment. To gain insight into the role of the UM microenvironment in regard to prognosis and metastatic progression, we have performed a pool analysis characterizing the UM microenvironment by using a bioinformatic approach. A variety of scores based on gene expression measuring stromal infiltration were calculated and used to assess association with prognosis. As a result, the highest immune and stromal scores were associated with poor prognosis. Specifically, stromal cells (fibroblasts and endothelial cells), T cells CD8+, natural killer (NK) cells, and macrophages M1 and M2 infiltration were associated with poor prognosis. Contrary to other tumors, lymphocytic infiltration is related to poor prognosis. Only B cells were associated with more favorable prognosis. UM samples scoring high in both angiogenesis (Angio) and antigen presentation (AP) pathways showed a poor prognosis suggesting an additive role of both functions. Almost all these tumors exhibited a chromosome 3 monosomy. Finally, an enrichment analysis showed that tumors classified as high Angio-high AP also activated metabolic pathways such as glycolysis or PI3K-AKT-MTOR. In summary, our pool analysis identified a cluster of samples with angiogenic and inflammatory phenotypes exhibiting poor prognosis and metabolic activation. Our analysis showed robust results replicated in a pool analysis merging different datasets from different analytic platforms

    Prey choice, provisioning behaviour, and effects of early nutrition on nestling phenotype of titmice

    Get PDF
    [EN] It is generally assumed that blue and great tits (Cyanistes caeruleus, Parus major) compete for the same type of food (Lepidoptera larvae) during the breeding season and that the former have some advantage because they are usually earlier and can exploit small caterpillars that are often more abundant and are not consumed by great tits. However, it is not clear whether, when confronted with similar circumstances (e.g., nestling demand), blue and great tits show similar preferences for a particular caterpillar type. In this 2-y study, we compare the diet of both tit species in detail by controlling for hatching date and brood size. We also examine how the contribution of caterpillars and spiders to the diet is related to nestling development. A positive relationship was found between the percentage of spiders in the diet and nestling tarsus length in both species, reinforcing the idea that neonatal nutrition could have a strong influence on nestling phenotype (e.g., offspring size). Such a correlation may arise because spiders contain a high level of taurine, an essential nutrient in the early development of young, and/or this prey type contains more calcium than other food items, which may affect the rate of nestling bone mineralization. Blue tits fed their young double the number of tortricid larvae in comparison with great tits, whereas the latter showed a clear preference for noctuids and exploited, with a low frequency, a type of larvae not consumed by blue tits, hairy caterpillars (Lasiocampidae). Our results point to resource partitioning by these species in this forest ecosystem and contribute to a better understanding of feeding ecology of titmice, which is particularly timely in a global warming context [FR] Il est généralement admis que les mésanges bleues (Cyanistes caeruleus) et les mésanges charbonnières (Parus major) se font compétition pour le même type de nourriture (larves de lépidoptères) durant la période de reproduction. Il est également admis que les mésanges bleues possèdent un certain avantage, car elles se reproduisent plus tôt et mangent de petites chenilles souvent plus abondantes qui ne sont pas consommées par les mésanges charbonnières. Cependant, il n'est pas clair si dans les mêmes conditions (ex. de demande en nourriture des oisillons), les mésanges bleues et charbonnières préfèrent les mêmes types de chenilles. Dans cette étude de 2 ans, nous avons comparé en détail les régimes alimentaires des 2 espèces de mésanges en contrôlant pour la date de ponte et la taille de la couvée. Nous avons aussi examiné si les contributions des chenilles et des araignées au régime alimentaire étaient reliées au développement des oisillons. Chez les 2 espèces, une relation positive a été trouvée entre le pourcentage d'araignées dans le régime alimentaire et la longueur du tarse des oisillons renforçant ainsi l'idée que la nutrition néonatale peut avoir une grande influence sur le phénotype des oisillons (ex. la taille des jeunes). Une telle corrélation peut résulter du fait que les araignées ont un taux élevé de taurine, un nutriment essentiel au développement précoce des jeunes, et/ou que ce type de proie contient plus de calcium que d'autres aliments ce qui peut influencer le taux de minéralisation des os chez les oisillons. Les mésanges bleues ont nourri leurs jeunes avec deux fois plus de larves de tortricidés que les mésanges charbonnières qui elles ont montré une nette préférence pour les noctuidés. Ces dernières ont aussi consommé, quoique peu fréquemment, des livrées (Lasiocampidae), un type de larves boudé par les mésanges bleues. Nos résultats pointent vers une division des ressources entre ces espèces dans cet écosystème forestier et contribuent à une meilleure compréhension de l'écologie alimentaire des mésanges ce qui est particulièrement utile dans un contexte de réchauffement climatiqueV. García-Navas was supported by a FPI predoctoral fellowship (Spanish Ministry of Science and Innovation (MICINN)-European Social Fund). This study was financed by the MICINN (grant reference: GCL2007-61395)Peer Reviewe

    Real-time experimental implementation of predictive control schemes in a small-scale pasteurization plant

    Get PDF
    Model predictive control (MPC) is one of the most used optimization-based control strategies for large-scale systems, since this strategy allows to consider a large number of states and multi-objective cost functions in a straightforward way. One of the main issues in the design of multi-objective MPC controllers, which is the tuning of the weights associated to each objective in the cost function, is treated in this work. All the possible combinations of weights within the cost function affect the optimal result in a given Pareto front. Furthermore, when the system has time-varying parameters, e.g., periodic disturbances, the appropriate weight tuning might also vary over time. Moreover, taking into account the computational burden and the selected sampling time in the MPC controller design, the computation time to find a suitable tuning is limited. In this regard, the development of strategies to perform a dynamical tuning in function of the system conditions potentially improves the closed-loop performance. In order to adapt in a dynamical way the weights in the MPC multi-objective cost function, an evolutionary-game approach is proposed. This approach allows to vary the prioritization weights in the proper direction taking as a reference a desired region within the Pareto front. The proper direction for the prioritization is computed by only using the current system values, i.e., the current optimal control action and the measurement of the current states, which establish the system cost function over a certain point in the Pareto front. Finally, some simulations of a multi-objective MPC for a real multi-variable case study show a comparison between the system performance obtained with static and dynamical tuning.Peer ReviewedPostprint (author's final draft

    Wildlife and Antibiotic Resistance

    Get PDF
    Antibiotic resistance is a major human health problem. While health care facilities are main contributors to the emergence, evolution and spread of antibiotic resistance, other ecosystems are involved in such dissemination. Wastewater, farm animals and pets have been considered important contributors to the development of antibiotic resistance. Herein, we review the impact of wildlife in such problem. Current evidence supports that the presence of antibiotic resistance genes and/or antibiotic resistant bacteria in wild animals is a sign of anthropic pollution more than of selection of resistance. However, once antibiotic resistance is present in the wild, wildlife can contribute to its transmission across different ecosystems. Further, the finding that antibiotic resistance genes, currently causing problems at hospitals, might spread through horizontal gene transfer among the bacteria present in the microbiomes of ubiquitous animals as cockroaches, fleas or rats, supports the possibility that these organisms might be bioreactors for the horizontal transfer of antibiotic resistance genes among human pathogens. The contribution of wildlife in the spread of antibiotic resistance among different hosts and ecosystems occurs at two levels. Firstly, in the case of non-migrating animals, the transfer will take place locally; a One Health problem. Paradigmatic examples are the above mentioned animals that cohabit with humans and can be reservoirs and vehicles for antibiotic resistance dissemination. Secondly, migrating animals, such as gulls, fishes or turtles may participate in the dissemination of antibiotic resistance across different geographic areas, even between different continents, which constitutes a Global Health issue. Copyright © 2022 Laborda, Sanz-García, Ochoa-Sánchez, Gil-Gil, Hernando-Amado and Martínez
    corecore