3,502 research outputs found

    Host immune response and pathological expression in malaria: possible implications for malaria vaccines

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    Recent progress in parasite immunobiology has led to the identification of several plasmodial antigens representing the target of the protective antibody response of the infected host. As a consequence, some of these antigens have been envisaged as potential malaria vaccines in man. However, in spite of these achievements, the fine mechanisms which lead to the development of a state of partial protective immunity or to the triggering of immunopathology during malaria infection are not yet fully understood. Thus, it may be appropriate to evaluate the relative importance of individual host immune responsiveness to parasite epitopes involved in the induction of immunity, or of some immunologically mediated adverse reactions such as glomerulonephritis, anaemia, thrombocytopenia, and cerebral syndrom

    The effective mass of two--dimensional 3He

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    We use structural information from diffusion Monte Carlo calculations for two--dimensional 3He to calculate the effective mass. Static effective interactions are constructed from the density-- and spin structure functions using sumrules. We find that both spin-- and density-- fluctuations contribute about equally to the effective mass. Our results show, in agreement with recent experiments, a flattening of the single--particle self--energy with increasing density, which eventually leads to a divergent effective mass.Comment: 4 pages, accepted in PR

    Optimizing the computation of overriding

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    We introduce optimization techniques for reasoning in DLN---a recently introduced family of nonmonotonic description logics whose characterizing features appear well-suited to model the applicative examples naturally arising in biomedical domains and semantic web access control policies. Such optimizations are validated experimentally on large KBs with more than 30K axioms. Speedups exceed 1 order of magnitude. For the first time, response times compatible with real-time reasoning are obtained with nonmonotonic KBs of this size

    Gully Formation at the Haughton Impact Structure (Arctic Canada) Through the Melting of Snow and Ground Ice, with Implications for Gully Formation on Mars

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    The formation of gullies on Mars has been the topic of active debate and scientific study since their first discovery by Malin and Edgett in 2000. Several mechanisms have been proposed to account for gully formation on Mars, from dry mass movement processes, release of water or brine from subsurface aquifers, and the melting of near-surface ground ice or snowpacks. In their global documentation of martian gullies, report that gullies are confined to ~2783S and ~2872N latitudes and span all longitudes. Gullies on Mars have been documented on impact crater walls and central uplifts, isolated massifs, and on canyon walls, with crater walls being the most common situation. In order to better understand gully formation on Mars, we have been conducting field studies in the Canadian High Arctic over the past several summers, most recently in summer 2018 and 2019 under the auspices of the Canadian Space Agency-funded Icy Mars Analogue Program. It is notable that the majority of previous studies in the Arctic and Antarctica, including our recent work on Devon Island, have focused on gullies formed on slopes generated by regular endogenic geological processes and in regular bedrock. How-ever, as noted above, meteorite impact craters are the most dominant setting for gullies on Mars. Impact craters provide an environment with diverse lithologies including impact-generated and impact-modified rocks and slope angle, and thus greatly variable hill slope processes could occur within a localized area. Here, we investigate the formation of gullies within the Haughton impact structure and compare them to gullies formed in unimpacted target rock in the nearby Thomas Lee Inle

    ENOBIO - First tests of a dry electrophysiology electrode using carbon nanotubes

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    We describe the development and first tests of Enobio, a dry electrode sensor concept for biopotential applications. In the proposed electrodes, the tip of the electrode is covered with a forest of multi-walled CNTs that can be coated with Ag/AgCl to provide ionic-electronic transduction. The CNT brush-like structure is to penetrate the outer layers of the skin improving electrical contact as well as increae the contact surface area. In this paper, we report the results of the first tests of this concept -- immersion on saline solution and pig skin signal detection. These indicate performance on a par with state of the art research-oriented wet electrodes.Comment: Submitted and accepted at the 28th IEEE EMBS International Conference, New York City, August 31st-September 3rd, 2006. Figures updated with proper filtering and averagin

    Beam heat load analysis with COLDDIAG: a cold vacuum chamber for diagnostics

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    The knowledge of the heat intake from the electron beam is essential to design the cryogenic layout of superconducting insertion devices. With the aim of measuring the beam heat load to a cold bore and understanding the responsible mechanisms, a cold vacuum chamber for diagnostics (COLDDIAG) has been built. The instrumentation comprises temperature sensors, pressure gauges, mass spectrometers and retarding field analyzers, which allow to study the beam heat load and the influence of the cryosorbed gas layer. COLDDIAG was installed in the storage ring of the Diamond Light Source from September 2012 to August 2013. During this time measurements were performed for a wide range of machine conditions, employing the various measuring capabilities of the device. Here we report on the analysis of the measured beam heat load, pressure and gas content, as well as the low energy charged particle flux and spectrum as a function of the electron beam parameters

    Psychometric properties of the Spanish version of the Clinical Outcomes in Routine Evaluation Outcome Measure

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    Objective: The objective of this paper is to assess the reliability and validity of the Spanish translation of the Clinical Outcomes in Routine Evaluation – Outcome Measure, a 34-item selfreport questionnaire that measures the client’s status in the domains of Subjective well-being, Problems/Symptoms, Life functioning, and Risk. Method: Six hundred and forty-four adult participants were included in two samples: the clinical sample (n=192) from different mental health and primary care centers; and the nonclinical sample (n=452), which included a student and a community sample. Results: The questionnaire showed good acceptability and internal consistency, appropriate test–retest reliability, and acceptable convergent validity. Strong differentiation between clinical and nonclinical samples was found. As expected, the Risk domain had different characteristics than other domains, but all findings were comparable with the UK referential data. Cutoff scores were calculated for clinical significant change assessment. Conclusion: The Spanish version of the Clinical Outcomes in Routine Evaluation – Outcome Measure showed acceptable psychometric properties, providing support for using the questionnaire for monitoring the progress of Spanish-speaking psychotherapy clients

    La interacción de procesos hidrológicos, químicos y microbiológicos en la formación de películas flotantes ricas en hierro en ambientes acuáticos de pH circumneutro

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    17 páginas.-- 3 figuras.-- 4 tablas.-- 53 referencias.-- Postprint (Versión editorial)[EN]: The direct contribution of microbial activity to the formation of iron-oxide minerals is difficult to prove in wetlands due to the high reactivity of solid iron phases with different compounds and the variety of redox processes that may occur at each oxic-anoxic boundary. Here, we propose an explanation for the formation of iron-oxide films in wetlands and groundwater seepage areas fed by sandy aquifers based on the interaction of hydrological, chemical and microbiological processes under circumneutral conditions. The presence of a floating iron-oxide film was found to create a boundary at the air-water interface that maintains a suboxic and slightly acidic environment below the film compared with the environments obtained in other free-film wetland areas. The water trapped below this film had an average pH of 6.1, was particularly poor in O2, HCO–3, Na+, Ca2+, Mg2+, K+, and Tot-S, and has high concentrations of Tot-P, Tot-Fe, NH+4 and Zn. The formation of a floating iron-oxide film was reproduced under anaerobic conditions after progressive enrichment through the incubation of natural sediment samples in the laboratory. Heterotrophic bacteria belonging to the genus Enterobacter were the dominant bacteria in the enrichments that resulted in the formation of a floating iron-oxide film. The X-ray diffraction patterns showed that the presence of two-line ferrihydrite was common to the iron-oxide films collected in both the natural environment and the laboratory cultures, whereas other iron-oxides (goethite and low-crystalline lepidocrocite) were observed only in the natural environment. This study highlights the role of ubiquitous bacteria, which are generally considered unimportant participants in iron-transformation processes in the environment, and the contribution of both biological and non-biological processes to iron oxidation in natural systems under circumneutral conditions.[ES]: En los humedales, es difícil probar que la actividad microbiana sea la responsable de la formación de óxido de hierro mineral debido, tanto a la gran reactividad del hierro en fase sólida con diferentes sustancias, como a la variedad de procesos redox que pueden ocurrir en cada interfase óxica-anóxica. El presente trabajo propone una explicación, basada en la interacción de procesos hidrológicos, químicos y microbiológicos en condiciones circumneutras, para explicar la formación de un film de óxido de hierro en humedales y manaderos donde aflora agua subterránea proveniente de acuíferos de arenas silíceas. Además, la presencia de un film de óxido de hierro que flota sobre la interfase agua-aire genera condiciones subóxicas y ligeramente ácidas en el agua que queda atrapada debajo, y que son muy distintas a otras zonas libres de film en el mismo humedal. Este agua atrapada bajo el film se caracterizó por presentar un pH medio de 6.1, una menor concentración de O2, HCO–3, Na+, Ca2+, Mg2+, K+, y S total, pero una mayor riqueza en P total, Fe total, NH+4 y Zn. La formación de un film flotante de óxido de hierro se reprodujo en el laboratorio, en condiciones anaeróbicas, tras el enriquecimiento progresivo de las muestras del sedimento natural que habían sido incubadas. En dichos enriquecimientos, donde se produjeron films flotantes de óxido de hierro, la bacteria dominante perteneció al género Enterobacter. Mediante difracción por rayos X, se encontró ferrihidrita con estructura en doble cadena, tanto en el film de muestras naturales como de cultivos de laboratorio. Además se encontraron otros tipos de óxidos minerales (goetita y lepidocrocita de pobre cristalización) sólo en las muestras naturales de film. El presente estudio muestra la relevancia de bacterias ubicuas, hasta ahora consideradas sin importancia en procesos naturales de transformación del hierro, y la participación tanto de procesos bióticos como abióticos en la oxidación del hierro en sistemas naturales sometidos a condiciones circumneutras.We are grateful to Han Golterman for his support and suggestions. We thank Lotte Fleskens and Christien van der Zwart for collaborating with the sediment collection and P-fractionation at the laboratory. This study was partially supported by the Spanish Ministry of Education and Science (CGL2004-03927-C02-01/BOS)Peer reviewe
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