165 research outputs found

    Tales from the South: a visual essay

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    Possible Clinical Failure of Artemether-Lumefantrine in an Italian Traveler with Uncomplicated Falciparum Malaria.

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    Artemisinin-combination therapies (ACTs) are recommended for the treatment of uncomplicated malaria in endemic areas with multidrug resistant Plasmodium falciparum. We report a case of possible artemether-lumefantrine clinical failure in an Italian traveler with uncomplicated P. falciparum malaria imported from Democratic Republic of Congo

    Life Cycle Assessment of Tomato Cultivated in an Innovative Soilless System

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    The main goal of this study is to present the life cycle assessment results of an innovative closed-loop production system, called an agriponic system, used for producing tomatoes. In the study, this new system is presented, as well as its related environmental impacts generated for the production of the tomatoes. A life cycle assessment (according to ISO 14040) was applied to it, from seedling purchase and planting to harvest, using a functional unit of 1 ton of cherry tomatoes produced. SimaPro 9.3.0.3 software and the Ecoinvent database were used to analyze five impact categories. Plant growth emerged as the process unit with the highest impact, particularly for the ozone depletion potential (ODP), with a value of 0.00056 kgCFC-11eq, and for photochemical oxidation (POCP), with a value of 0.0784 kgC2H4eq impact categories. Greenhouse climate management presented a significant impact to the acidification potential (AP), with a value of 1.021 kgSO2eq. Conversely, the phases of plant transplanting, harvesting, and crop disposal had positive impacts for all impact categories considered in the study, because they were very low. In conclusion, agriponic greenhouse tomato production is a sustainable process. This is due to fewer pesticides that are used, and to nutrient solution reuse

    Unsupervised methodology to unveil content delivery network structures

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    A method for analyzing a content delivery network. The method includes obtaining network traffic flows corresponding to user nodes accessing contents from a set of servers of the content delivery network, extracting a timing attribute from each network traffic flow associated with a server, where the timing attribute is aggregated into a timing attribute dataset of the server based on all network traffic flows associated with the server, generating a statistical measure of the timing attribute dataset as a portion of a feature vector representing the server, where the feature vector is aggregated into a set of feature vectors representing the set of servers, analyzing the set of feature vectors based on a clustering algorithm to generate a set of clusters, and generating, based on the set of clusters, a representation of server groups in the content delivery network

    Accurate pHEMT nonlinear modeling in the presence of low-frequency dispersive effects

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    Low-frequency (LF) dispersive phenomena due to device self-heating and/or the presence of "traps" (i.e., surface state densities and bulk spurious energy levels) must be taken into account in the large-signal dynamic modeling of III-V field-effect transistors when accurate performance predictions are pursued, since these effects cause important deviations between direct current (dc) and dynamic drain current characteristics. In this paper, a new model for the accurate characterization of these phenomena above their cutoff frequencies is presented, which is able to fully exploit, in the identification phase, large-signal current-voltage (I-V) measurements carried out under quasi-sinusoidal regime using a recently proposed setup. Detailed experimental results for model validation under LF small- and large-signal operating conditions are provided. Furthermore, the I-V model proposed has been embedded into a microwave large-signal pseudomorphic high electron-mobility transistor (pHEMT) model in order to point out the strong influence of LF modeling on the degree of accuracy achievable under millimeter-wave nonlinear operation. Large-signal experimental validation at microwave frequencies is provided for the model proposed, by showing the excellent intermodulation distortion (IMD) predictions obtained with different loads despite the very low power level of IMD products involved. Details on the millimeter-wave IMD measurement setup are also provided. Finally, IMD measurements and simulations on a Ka-band highly linear power amplifier, designed by Ericsson using the Triquint GaAs 0.25-/spl mu/m pHEMT process, are shown for further model validation

    Few-body precursors of topological frustration

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    Quantum spin chains - the prototypical model for coupled two-level systems - offer a fertile playground both for fundamental and technological applications, ranging from the theory of thermalization to quantum computation. The effects of frustration induced by the boundary conditions have recently been addressed in this context. In this work, we analyze the effects of such frustration on a few spin system and we comment the strong even-odd effects induced in the ground state energy. The purpose of this work is to show that such signatures are visible on current quantum computer platforms

    Plan de negocio de una empresa consultora en gestión de contratos de construcción

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    Uno de los principales problemas en la ejecución de proyectos de construcción son las controversias por los mayores plazos de ejecución y sobre las contraprestaciones para lograr el objetivo del cliente. Estas controversias se pueden gestionar a través de los mecanismos que los propios contratos estipulan, o por la normativa y la regulación vigente. El presente plan de negocios de una empresa consultora en gestión de contratos de construcción tiene como objetivo principal determinar la rentabilidad y la viabilidad del negocio, basado en que la cantidad de procesos arbitrales por obras de construcción por año en el Perú se ha ido incrementando desde el 2008. Ello nos muestra que existe una tendencia en cuanto a cómo los clientes y los contratistas solucionan sus controversias. Es así cómo lo más recomendable es desplegar una eficiente gestión de contrato, ya sea para mitigar controversias o para estar en mejor posición y capacidad de justificar una determinada posición, ya sea como cliente o contratista. Es por ello por lo que una consultora que ayude a contratistas y clientes a poder dar un juicio de valor, ya sea mediante una evaluación técnica específica o un acompañamiento en la gestión del contrato, se convierte en una oportunidad frente a una problemática existente y que cada vez es más frecuente en los proyectos de construcción en el Perú, tanto en el sector público como el privado. En la medida en que los contratistas y los clientes consideren atractivo gestionar y resolver sus controversias usando las buenas prácticas en la industria, así como metodologías y procedimientos recomendados internacionalmente, la idea de negocio será más atractiva y rentable

    Caracterización molecular de cepas invasivas de Streptococcus dysgalactiae subsp. equisimilis. Estudio multicéntrico Argentina 2011-2012

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    [EN] Streptococcus dysgalactiae subsp. equisimilis (SDSE) has virulence factors similar to those of Streptococcus pyogenes. Therefore, it causes pharyngitis and severe infections indistinguishable from those caused by the classic pathogen. The objectives of this study were: to know the prevalence of SDSE invasive infections in Argentina, to study the genetic diversity, to determine the presence of virulence genes, to study antibiotic susceptibility and to detect antibiotic resistance genes. Conventional methods of identification were used. Antibiotic susceptibility was determined by the disk diffusion and the agar dilution methods and the E-test. Twenty eight centers from 16 Argentinean cities participated in the study. Twenty three isolates (16 group G and 7 group C) were obtained between July 1 2011 and June 30 2012. Two adult patients died (8.7%). Most of the isolates were recovered from blood (60.9%). All isolates carried speJ and ssa genes. stG62647, stG653 and stG840 were the most frequent emm types. Nineteen different PFGE patterns were detected. All isolates were susceptible to penicillin and levofloxacin, 6 (26.1%) showed resistance or reduced susceptibility to erythromycin [1 mef(A), 3 erm(TR), 1 mef(A)+erm(TR) and 1 erm(TR)+erm(B)] and 7 (30.4%) were resistant or exhibited reduced susceptibility to tetracycline [2 tet(M), 5 tet(M)+tet(O)]. The prevalence in Argentina was of at least 23 invasive infections by SDSE. A wide genetic diversity was observed. All isolates carried speJ and ssa genes. Similarly to other studies, macrolide resistance (26.1%) was mainly associated to the MLSB phenotype. [ES] Streptococcus dysgalactiae subsp. equisimilis (SDSE) posee factores de virulencia similares a Streptococcus pyogenes y, en consecuencia, produce faringitis e infecciones graves indistinguibles de las generadas por este patógeno clásico. Los objetivos del estudio fueron conocer la prevalencia de SDSE en infecciones invasivas en Argentina, estudiar su diversidad genética, determinar la presencia de genes de virulencia, ensayar su sensibilidad a los antibióticos y conocer los genes de resistencia. Se emplearon métodos convencionales de identificación. La sensibilidad se determinó por difusión, Etest y dilución en agar. Participaron 28 centros de 16 ciudades argentinas. Se obtuvieron 23 aislamientos (16 del grupo G y 7 del grupo C) desde el 1-7-2011 hasta el 30-6-2012. Se registraron 2 muertes en adultos (8,7%). La mayoría de los aislamientos fueron obtenidos de sangre (60,9%). Todos eran portadores de los genes speJ y ssa. Los genotipos más frecuentes fueron stG62647, stG653 y stG840. Se detectaron 19 pulsotipos distintos. Todos los aislamientos fueron sensibles a penicilina y levofloxacina, 6 (26,1%) presentaron resistencia o sensibilidad disminuida a eritromicina (1 mef[A], 3 erm[TR], 1 mef[A] + erm[TR] y 1 erm[TR] + erm[B]) y 7 (30,4%) fueron resistentes o tuvieron sensibilidad disminuida a tetraciclina (2 tet[M], 5 tet[M] + tet[O]). La prevalencia anual en la Argentina fue de al menos 23 infecciones invasivas por SDSE y se observó una amplia diversidad genética. Todos los aislamientos presentaron los genes ssa y speJ. Como en otros estudios, la resistencia a macrólidos (26,1%) estuvo asociada, principalmente, al fenotipo MLSB.S

    Sustainable assessment of learning experiences based on projects

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    In a project-based learning experience, the detailed monitoring of the activities in which team members participate can be useful to evaluate their work. Using learning-oriented assessment procedures, supervisors can assess the teamwork abilities with a formative purpose. Evaluation strategies such as self-assessment, peer assessment and co-assessment are often used to make evaluation formative and sustainable. Conducting an assessment strategy is not easy for team members, since they need before to have a reasonable understanding of the evaluation process and criteria. This paper describes a learning-oriented evaluation methodology and an open data framework that can be applied to collaborative project settings. An evaluation rubric and a series of indicators that provide evidences about the developed skills have been elaborated and applied in a small-scale project-based course. Projects were managed and developed with the help of an open source software forge that contains a ticketing tool for planning and tracking of tasks, a version control repository to save the software outcomes, and using a wiki to host text deliverables. The experience provides evidences in favor of using the assessment method and open data framework to make teamwork evaluation more sustainable.En las experiencias de aprendizaje basadas en proyectos, la monitorización detallada de las actividades de los miembros de cada equipo puede resultar de utilidad para la evaluación de su trabajo. Mediante procedimientos de evaluación, los supervisores pueden evaluar las capacidades de trabajo en equipo con una finalidad formativa. Suelen aplicarse estrategias como la auto-evaluación, la evaluación entre iguales y la co-evaluación para hacer que la evaluación formativa sea sostenible. Seguir una estrategia de evaluación no es siempre sencillo para los miembros de los equipos, pues necesitan un conocimiento razonable del proceso y los criterios de evaluación. Este artículo describe una metodología de evaluación orientada al aprendizaje y un framework software de datos abiertos aplicable a la evaluación de proyectos de desarrollo colaborativo. Se han elaborado una rúbrica y una serie de indicadores que proporcionan evidencias sobre las habilidades y, posteriormente, se han aplicado a un curso basado en proyectos de pequeña escala. Los proyectos se gestionaron y ejecutaron con la ayuda de una forja de software libre que incluye una herramienta de gestión de tareas para la planificación y el seguimiento, un repositorio de control de versiones para almacenar el software entregable y una wiki para almacenar los entregables textuales. La experiencia ha proporcionado evidencias a favor del método de evaluación y el framework de datos abiertos para hacer la evaluación del trabajo en equipo más sostenible
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