771 research outputs found

    The Automated Root Exudate System (ARES): a method to apply solutes at regular intervals to soils in the field.

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    Root exudation is a key component of nutrient and carbon dynamics in terrestrial ecosystems. Exudation rates vary widely by plant species and environmental conditions, but our understanding of how root exudates affect soil functioning is incomplete, in part because there are few viable methods to manipulate root exudates in situ. To address this, we devised the Automated Root Exudate System (ARES), which simulates increased root exudation by applying small amounts of labile solutes at regular intervals in the field. The ARES is a gravity-fed drip irrigation system comprising a reservoir bottle connected via a timer to a micro-hose irrigation grid covering c. 1 m2; 24 drip-tips are inserted into the soil to 4-cm depth to apply solutions into the rooting zone. We installed two ARES subplots within existing litter removal and control plots in a temperate deciduous woodland. We applied either an artificial root exudate solution (RE) or a procedural control solution (CP) to each subplot for 1 min day-1 during two growing seasons. To investigate the influence of root exudation on soil carbon dynamics, we measured soil respiration monthly and soil microbial biomass at the end of each growing season. The ARES applied the solutions at a rate of c. 2 L m-2 week-1 without significantly increasing soil water content. The application of RE solution had a clear effect on soil carbon dynamics, but the response varied by litter treatment. Across two growing seasons, soil respiration was 25% higher in RE compared to CP subplots in the litter removal treatment, but not in the control plots. By contrast, we observed a significant increase in microbial biomass carbon (33%) and nitrogen (26%) in RE subplots in the control litter treatment. The ARES is an effective, low-cost method to apply experimental solutions directly into the rooting zone in the field. The installation of the systems entails minimal disturbance to the soil and little maintenance is required. Although we used ARES to apply root exudate solution, the method can be used to apply many other treatments involving solute inputs at regular intervals in a wide range of ecosystems

    RNA Isolation of Pseudomonas aeruginosa Colonizing the Murine Gastrointestinal Tract

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    Pseudomonas aeruginosa (PA) infections result in significant morbidity and mortality in hosts with compromised immune systems, such as patients with leukemia, severe burn wounds, or organ transplants1. In patients at high-risk for developing PA bloodstream infections, the gastrointestinal (GI) tract is the main reservoir for colonization2, but the mechanisms by which PA transitions from an asymptomatic colonizing microbe to an invasive, and often deadly, pathogen are unclear. Previously, we performed in vivo transcription profiling experiments by recovering PA mRNA from bacterial cells residing in the cecums of colonized mice 3 in order to identify changes in bacterial gene expression during alterations to the host’s immune status

    Erectile Dysfunction in People with HIV – A Scoping Review

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    Objetivo: Exponer los factores que han sido asociados al desarrollo de disfunción eréctil (DE) en las personas con virus de la inmunodeficiencia humana (VIH) y cuál es la prevalencia de la disfunción eréctil en esta población. Métodos: Se realizó una revisión de alcance utilizando las siguientes bases de datos: MEDLINE, CENTRAL, Embase, Scopus, Lilacs, y Psycinfo. Los artículos incluidos debían tener cualquier información relacionada con la DE en personas con VIH, su prevalencia, y posibles factores asociados. Se filtraron un total de 2.726 artículos por título y resumen, y, de estos, se seleccionaron 22 referencias para revisión de texto completo y análisis. Resultados: Se encontró que las personas con VIH tienen una mayor probabilidad de presentar DE en comparación con las personas sin VIH. Algunos estudios han establecido una asociación entre la DE y trastornos psicológicos o factores orgánicos, como la lipodistrofia, la hipertensión arterial, la hipercolesterolemia, la diabetes mellitus, la depresión, la ansiedad, y el hipogonadismo. La ingesta de terapia antirretroviral (TARV), más específicamente los inhibidores de la proteasa, sigue siendo cuestionada como causante de DE en pacientes con VIH. Conclusiones: Ante un paciente con diagnóstico de VIH, se debe ahondar sobre DE con el fin de recomendar e iniciar conductas terapéuticas que aseguren un mejoramiento en su calidad de vida.Q4Hombres con Virus de la Inmunodeficiencia Humana (VIH)Aim: To present factors that have been associated with the development of erectile dysfunction (ED) in people with human immunodeficiency virus (HIV) and the frequency of erectile dysfunction among this population. Methods: We performed a scoping review on the following databases: MEDLINE, CENTRAL, Embase, Scopus, Lilacs, and Psycinfo. The articles included information related to ED in people with HIV, its frequency, and possible associated factors. A total of 2,726 articles were filtered by title and abstract, and, from these, 22 references were selected for full-text review and analysis. Results: People with HIV were found to be more likely to have ED compared to people without HIV. Some studies have established an association between ED and psychological disorders or organic factors, such as lipodystrophy, high blood pressure, hypercholesterolemia, diabetes mellitus, depression, anxiety, and hypogonadism. The intake of antiretroviral therapy (ART), more specifically protease inhibitors, continues to be questioned as a cause of ED in patients with HIV. Conclusions: In HIV-positive men, we recommend to actively seek ED in order to initiate therapeutic conducts that can ensure an improvement in their quality of life.https://orcid.org/0000-0002-1416-3201https://orcid.org/0000-0003-3355-2816https://orcid.org/0000-0002-2914-429Xhttps://orcid.org/0000-0002-0885-7960https://orcid.org/0000-0002-5895-3029Revista Nacional - IndexadaCN

    Self perception of body attractiveness in two cultures: Mexican and Argentine

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    In order to describe the level of physical attractiveness that mexican and argentine consider having, we worked with an intentional non-probabilistic sample composed of 272 university students shared equally by nationality and gender from the cities of Toluca (Mexico) and Mendoza (Argentina). The instrument used was physical attractiveness assessment, which evaluates the attractiveness of the visible body parts from 0 to 100%. The research findings by nationality show that mexican people value more their body parts compared with argentinean. Sex differences indicate that mexican men tend to consider more attractive their body parts than mexican women. However, argentinean people show no difference in the number of body parts evaluated as attractive. In both nationalities, there is a tendency to put a higher value on body parts considered masculine by men and feminine by women. In general, it appears that the body is and will remain an important mean of expression and the value that it is given will establish the degree of security that people has to relate to their particular psychological, sociological and cultural context

    Biosynthesis of Silver Nanoparticles on Orthodontic Elastomeric Modules: Evaluation of Mechanical and Antibacterial Properties

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    Abstract: In the present study, silver nanoparticles (AgNPs) were synthesized in situ on orthodontic elastomeric modules (OEM) using silver nitrate salts as metal-ion precursors and extract of the plant Hetheroteca inuloides (H. inuloides) as bioreductant via a simple and eco-friendly method. The synthesized AgNPs were characterized by UV-visible spectroscopy; scanning electron microscopy-energy-dispersive spectroscopy (SEM-EDS) and transmission electron microscopy (TEM). The surface plasmon resonance peak found at 472 nm confirmed the formation of AgNPs. SEM and TEM images reveal that the particles are quasi-spherical. The EDS analysis of the AgNPs confirmed the presence of elemental silver. The antibacterial properties of OEM with AgNPs were evaluated against the clinical isolates Streptococcus mutans, Lactobacillus casei, Staphylococcus aureus and Escherichia coli using agar diffusion tests. The physical properties were evaluated by a universal testing machine. OEM with AgNPs had shown inhibition halos for all microorganisms in comparison with OEM control. Physical properties increased with respect to the control group. The results suggest the potential of the material to combat dental biofilm and in turn decrease the incidence of demineralization in dental enamel, ensuring their performance in patients with orthodontic treatmentUAEME

    Vegetal food among indigenous people from the Diagonal Árida of Argentina: Central Hills, Dry Pampas and Northern Patagonia

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    Analizamos información arqueológica recuperada en los últimos años sobre la alimentación vegetal entre comunidades originarias de la diagonal árida argentina, en las latitudes centrales del país. El artículo se focaliza en tres áreas, Sierras Centrales, Pampa Seca y Norpatagonia, con un examen que destaca aspectos compartidos y particularidades locales. Se toman en cuenta trayectorias prehispánicas del Holoceno tardío, entre 4000 y 400 años antes del presente. El repaso incluye problemáticas en torno al acceso, procesamiento y consumo de especies silvestres, abarcando árboles, arbustos, palmeras y gramíneas, algunas de distribución generalizada y otras restringidas a entornos acotados. También se consideran especies domesticadas, cultivadas en algunas áreas y periodos, o integradas en redes de intercambio entre grupos agricultores y cazadores-recolectores.In this paper we analyze archaeological data on vegetable food among indigenous people from the “Arid diagonal”, in the middle latitudes of Argentina. We focus on three main areas: Central Ranges, Dry Pampas and extra-andean Northern Patagonia, and offer an examination of both shared cultural features and local particularities. We place the analysis on pre-hispanic late Holocene (4000-400 years before present). Our review comprises general issues such as access, processing and consumption of wild species, including trees, shrubs, palms and grasses, with both wide and local distributions. We also consider domesticated species cultivated on some specific times and locations or integrated in exchange networks between farmers and hunter gatherer societies.Fil: Lopez, María Laura. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Arqueología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Beron, Monica Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto de las Culturas. Universidad de Buenos Aires. Instituto de las Culturas; ArgentinaFil: Prates, Luciano Raúl. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Arqueología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Medina, Matias Eduardo. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Arqueología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Heider, Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Departamento de Geología; ArgentinaFil: Pastor, Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Catamarca. Universidad Nacional de Catamarca. Centro de Investigaciones y Transferencia de Catamarca; Argentin

    Recruitment limitation in three large‐seeded plant species in a tropical moist forest

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    Recruitment limitation—the failure of a species to establish recruits at an available site—is a potential determinant of plant communities’ structure, causing local communities to be a limited subset of the regional species pool. Recruitment limitation results from three mechanisms: (i) lack of seed sources (i.e., source limitation), (ii) failure of available seeds to reach recruitment sites (i.e., dispersal limitation), and (iii) failure of arrived seeds to establish at a location (i.e., establishment limitation). Here, we evaluated the relative importance of these mechanisms in three co-occurring tree species (Dipteryx oleifera, Attalea butyracea, and Astrocaryum standleyanum) that share seed dispersers/predators. The study was set up on Barro Colorado Island (Panama) at 62 one-ha sites with varying tree densities. Source limitation was estimated as the proportion of sites that would be reached by seeds if seeds were distributed uniformly. Dispersal limitation was estimated from the number of sites with seeds in the soil bank. Establishment limitation was evaluated by measuring germination and 1-year survival in seed addition experiments. The effect of conspecific and heterospecific densities on the mechanisms was evaluated at three spatial scales (1, 5, and 9 ha). For all species, seed predation was the most important recruitment component (~80% decrease in seed survival). Establishment varied among species and was affected by conspecific and heterospecific species densities across spatial scales. Given that species identity, distribution, and seed dispersal/predation affect recruitment at multiple scales, multiscale studies are required to understand how recruitment limitation determines community structure in tropical forests

    Los programas de educación náutica en la educación obligatoria en España: revisión sistemática

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    En los últimos años, los deportes náuticos están adquiriendo notoriedad en el ámbito educativo, pudiendo demostrar que son una herramienta valiosa para el desarrollo integral de los estudiantes. Sin embargo, no parece existir evidencia científica sobre el desarrollo y efecto de estos en los programas de educación náutica en España. Por ello, el objetivo de este estudio fue la realización de una revisión sistemática de los programas relacionados con la educación náutica en la educación Primaria y Secundaria en España. Además, proponer un meta-programada en la línea de esta temática. A partir de estos objetivos, se realizó la búsqueda en las bases de datos PubMed, Scopus, Dialnet, Web of Science y, posteriormente, en Google Académico y en el buscador de Google, entre 2008 hasta 2023 empleando las siguientes palabras clave: "programa escolar", "educación", "actividades náuticas".  Los resultados de la búsqueda muestran que los principales objetivos de estos programas son el fomento de actividades y deportes náuticos y el conocimiento del propio entorno. En cuanto a los contenidos, destaca el uso de los deportes de vela, y otros deportes como son piragüismo, windsurf, kayak o paddle surf, que empiezan por clases teóricas, para posteriormente, realizar las clases prácticas. En conclusión, se ha podido comprobar que, en la actualidad, se está haciendo un uso deportes náuticos en el ámbito educativo, lo que nos ha llevado a realizar un meta-programa donde se recojan la información más relevante de los objetivos, contenidos, metodología y evaluación

    Kinescan/IBV V11: Biomechanical assessment in real time

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    [EN] Experts in biomechanical assessment are very interested in increasing precision of the measurements, reducing the needed time for evaluating patients and giving more flexibility to their labs. Therefore, we developed a new version of our system for kinematic analysis of human movement: Kinescan/IBV V11. Kinescan/IBV V11 is based in digital video technology and is able to make a distributed pre-processing. So it can analyse automatically movements in real time and use an unlimited number of cameras. The labs of functional assessment can reduce their costs, reduce their needed time for the assessment and increase their precision and reliability.[ES] El interés de los expertos en valoración biomecánica por incrementar la precisión de las medidas, reducir los tiempos de valoración y dotar de mayor flexibilidad a sus laboratorios es cada vez más creciente. Por esos motivos, hemos desarrollado una nueva versión de nuestro sistema de análisis cinemático de los movimientos humanos: Kinescan/IBV V11. Kinescan V11 es un sistema basado en tecnología vídeo digital con preprocesado distribuido que permite, entre otras características, analizar los movimientos en tiempo real y de forma automática y utilizar cuantas cámaras sean necesarias. Gracias a esta tecnología, los laboratorios de valoración funcional del IBV podrán reducir sus costes de operación, reducir los tiempos de valoración e incrementar su precisión y fiabilidad.Montero Vilela, J.; Parra Gonzalez, F.; Parrilla Bernabé, E.; Medina Ripoll, E.; Lopez Pascual, J.; Moreno Cano, R.; Castelli., A.... (2013). Kinescan/IBV v11: Valoración biomecánica en tiempo real. Revista de biomecánica. 59:35-38. http://hdl.handle.net/10251/38676S35385

    Estudio de perfiles de difracción de rayos X de una aleación Ti-13Ta-3Sn obtenida por aleado mecánico

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    Las aleaciones Ti-β se han vuelto altamente demandadas en la industria, por sus buenas características físicas y químicas. En el presente trabajo, se sintetizó una aleación Ti-13Ta-3Sn (%at) por aleado mecánico con tiempos entre 2 y 100h. Las aleaciones se caracterizaron por difracción de rayos X (DRX) y los patrones se analizaron por el método Rietveld con el software MAUD. Se caracterizaron los cambios microestructurales y la evolución de las fases Ti-α y Ti-β. Se identificó la presencia una nueva fase metaestable fcc y la síntesis de una aleación con un 79,80% en peso de fase Ti-β, ambas con tamaño de cristalita nanométrico. Palabras clave: Aleado mecánico, aleación Ti-β, difracción de rayos X
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