160 research outputs found

    Dependence of the drag over super hydrophobic and liquid infused surfaces on the textured surface and Weber number

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    Direct Numerical Simulations of a turbulent channel flow have been performed. The lower wall of the channel is made of staggered cubes with a second fluid locked in the cavities. Two viscosity ratios have been considered, m=μ1/μ2=0.02 and 0.4 (the subscript 1 indicates the fluid in the cavities and 2 the overlying fluid) mimicking the viscosity ratio in super–hydrophobic surfaces (SHS) and liquid infused surfaces (LIS) respectively. A first set of simulations with a slippery interface has been performed and results agree well with those in literature for perfect slip conditions and Stokes approximations. To assess how the dynamics of the interface affects the drag, a second set of DNS has been carried out at We=40 and 400 corresponding to We+≃10−3 and 10−2. The deformation of the interface is fully coupled to the Navier-Stokes equation and tracked in time using a Level Set Method. Two gas fractions, GF=0.5 and 0.875, have been considered to assess how the spacing between the cubes affects the deformation of the interface and therefore the drag. For the dimensions of the substrate here considered, under the ideal assumption of flat interface, staggered cubes with GF=0.875 provide about 20% drag reduction for We=0. However, a rapid degradation of the performances is observed when the dynamics of the interface is considered, and the same geometry increases the drag of about 40% with respect to a smooth wall. On the other hand, the detrimental effect of the dynamics of the interface is much weaker for GF=0.5 because of the reduced pitch between the cubes

    Trends in the extinction of carnivores in Madagascar

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    Tendencias de la extinción de carnívoros en Madagascar La extinción de los depredadores apicales, como los mamíferos carnívoros, puede conllevar cambios drásticos en la estructura de la red alimentaria y la dinámica de los ecosistemas. Dado que todos los mamíferos carnívoros terrestres autóctonos de Madagascar son endémicos, su extinción implica una pérdida notable de biodiversidad en este país. En el presente artículo examinamos las publicaciones sobre mamíferos carnívoros de Madagascar con el propósito de determinar cuáles son las especies que tienen mayor probabilidad de extinguirse en un futuro próximo, en vista de los factores que amenazan su supervivencia. Puntuamos cada factor en función de los efectos que ejerce en las especies. Según nuestros resultados, la especie que tiene más probabilidad de extinguirse es la mangosta rayada grande, Galidictis grandidieri, lo cual no es sorprendente porque esta especie se considera uno de los carnívoros más escasos del mundo, que habita solo en un ecosistema forestal pequeño y amenazado. Asimismo, nuestros resultados ponen de manifiesto la necesidad de disponer de datos sólidos sobre cada especie, a fin de ayudar y respaldar a las autoridades a poner en práctica medidas de conservación.The extinction of top predators, such as mammalian carnivores can lead to dramatic changes in foodweb structure and ecosystem dynamics. Since all native Malagasy terrestrial mammalian carnivores are endemic, their extinction implies a significant loss of biodiversity in Madagascar. Here we review the literature on Madagascar’s mammalian carnivores, aiming to determine which species are most likely to become extinct in the near future in view of the factors threatening their survival. We scored each factor according to its impact on the species. According to our results, the giant–striped mongoose, Galidictis grandidieri, is the most likely species to next become extinct. This is no surprise because this species is considered one of the rarest carnivores in the world, inhabiting only a small, threatened forest ecosystem. Our results emphasize the need for robust data about each species to help and support decision–makers implement conservation measures.Tendencias de la extinción de carnívoros en Madagascar La extinción de los depredadores apicales, como los mamíferos carnívoros, puede conllevar cambios drásticos en la estructura de la red alimentaria y la dinámica de los ecosistemas. Dado que todos los mamíferos carnívoros terrestres autóctonos de Madagascar son endémicos, su extinción implica una pérdida notable de biodiversidad en este país. En el presente artículo examinamos las publicaciones sobre mamíferos carnívoros de Madagascar con el propósito de determinar cuáles son las especies que tienen mayor probabilidad de extinguirse en un futuro próximo, en vista de los factores que amenazan su supervivencia. Puntuamos cada factor en función de los efectos que ejerce en las especies. Según nuestros resultados, la especie que tiene más probabilidad de extinguirse es la mangosta rayada grande, Galidictis grandidieri, lo cual no es sorprendente porque esta especie se considera uno de los carnívoros más escasos del mundo, que habita solo en un ecosistema forestal pequeño y amenazado. Asimismo, nuestros resultados ponen de manifiesto la necesidad de disponer de datos sólidos sobre cada especie, a fin de ayudar y respaldar a las autoridades a poner en práctica medidas de conservación

    School Social Workers’ Perceptions of Compassion Fatigue Syndrome

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    School social workers face domestic violence, trauma, social violence, and mental and emotional health problems in their work context. Indeed, compassion fatigue results from professionals’ continuous exposure to these problems. This study explored school social work professionals’ perceptions of compassion fatigue. For this, the following questions were explored:the perception of school social workers working for the Puerto Rico Department of Education about compassion fatigue

    Successful Practices in Performing and Maintaining Physical Activity in Adults with Type 2 Diabetes Mellitus: A Qualitative Study

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    Physical activity has proven to be greatly beneficial in patients with DM2. However, few adhere to physical activity recommendations and are motivated to engage in regular physical activity and the numerous interventions conducted to change their habits tend to be unsuccessful in the long term. The objective in this research is to study patients who adhere to physical activity in order to guide patients who have not succeeded in making this change, assisted by the successful tools in the context of community nursing. A qualitative descriptive study was conducted. The sample included 10 patients with type 2 diabetes mellitus who adhered to physical activity in Catalonia, Spain, having been selected using intentional sampling. We recorded semi-structured interviews with the participants and conducted a thematic analysis. Five categories were identified and grouped into two themes: (1) Integrate physical activity as a lifestyle (meaning of DM2 and physical activity, adaptation to change and strategies on a day-to-day basis, physical activity) and (2) Find support to change physical activity (company and personal motivational strategies). In conclusion, a good adherence to physical activity was achieved thanks to motivation maintained over time related to autonomous motivation and the psychological and physiological benefits that physical activity provides patients, external support and encouragement, and the allocation of time to adhere without making great lifestyle changes

    MUST, a multicast synchronous transfer application for fast intra-campus replications

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    In this paper, we introduce a new multicast application called MUST (multicast synchronous transfer) that allows the replication of hard disk partitions in a fast and efficient way. The main goal of MUST is to help system administrators to easily maintain and update all computers in a lab. MUST transmits its IP packets in multicast mode, avoiding the use of unnecessary bandwidth. Unfortunately, the well known TCP transport protocol cannot be used in this multicast environment since the number of TCP flow control windows (and consequently, the number of ACK) that server should process, grow exponentially. Therefore, we also outline an alternative. multicast transport protocol specifically designed for this application. This way, the number of acknowledge frames are drastically reduced, allowing the use of MUST application in a LAN and intra-campus (directly interconnected LANs via few routers). scenarios. The application has been programmed in C language using standard kernel routines, therefore, MUST can mount almost all existing file systems. In addition, we can distribute our application world wide without incurring legal conflicts.This work has been supported by the Spanish Research Council under projects FARIP (TIC2000- 1734-C03-03) and MTCES (TIC2001-3339-C02-02)

    Obtención y cromatografía gas-líquido de aldosulosas (Osónos)

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    The aldosuloses of D-xilose, D-glucose, D-galactose, L-sorbose, D-lactose and D-maltose are obtained. Melting point, elemental analysis, I.R. and U.V. espectra, and retention distances by gas-liquid chromatography, in two colums, have been calculated

    Irrigation performance and gross water productivity in furrow-irrigated ornamental tree production

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    In the ornamental plant production region of Girona (Spain), which is one of the largest of its kind in southern Europe, most of the surface is irrigated using wide blocked-end furrows. The objectives of this paper were: (1) to evaluate the irrigation scheduling methods used by ornamental plant producers; (2) to analyse different scenarios in order to assess how they affect irrigation performance; (3) to evaluate the risk of deep percolation; and (4) to calculate gross water productivity. A two-year study in a representative commercial field, planted with Prunus cerasifera ‘Nigra’, was carried out. The irrigation dose applied by the farmers was slightly smaller than the required water dose estimated by the use of two different methods: the first based on soil water content, and the second based on evapotranspiration. Distribution uniformity and application eff iciency were high, with mean values above 87%. Soil water content measurements revealed that even at the end of the furrow, where the infiltrated water depth was greatest, more than 90% of the infiltrated water was retained in the shallowest 40 cm of the soil; accordingly, the risk of water loss due to deep percolation was minimal. Gross water productivity for ornamental tree production was € 11.70 m–3, approximately 20 times higher than that obtained with maize in the same region.En la zona de producción de planta ornamental de Girona (España), que es una de las mayores del sur de Europa, la mayor parte de la superficie es regada por surcos. Los objetivos del presente artículo son: (1) evaluar la programación de riegos que realizan los productores de planta ornamental; (2) analizar diferentes escenarios para ver como afectan la calidad del riego; (3) evaluar el riesgo de percolación profunda; (4) calcular la productividad bruta del agua. Se realizó un estudio de dos años en un campo comercial de Prunus cerasifera ‘Nigra’. La dosis de agua aplicada por los agricultores fue ligeramente inferior a la dosis de riego requerida estimada por dos métodos distintos: el primero basado en el contenido de agua en el suelo y el segundo en la evapotranspiración. La uniformidad de distribución y eficiencia de aplicación fueron altos, con valores medios por encima del 87%. Las medidas de contenido de agua en el suelo revelaron que al final del surco, donde la lámina de agua infiltrada fue mayor, más del 90% del agua infiltrada se retuvo en los primeros 40 cm del suelo; en consecuencia, el riesgo de pérdidas de aguas debido a la percolación profunda fue mínimo. La productividad bruta del agua en la producción de árboles ornamentales fue de 11,70 € m–3, aproximadamente 20 veces mayor que la obtenida en maíz en la misma región

    A myosin chaperone, UNC-45A, is a novel regulator of intestinal epithelial barrier integrity and repair

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    The actomyosin cytoskeleton serves as a key regulator of the integrity and remodeling of epithelial barriers by controlling assembly and functions of intercellular junctions and cell-matrix adhesions. Although biochemical mechanisms that regulate the activity of non-muscle myosin II (NM-II) in epithelial cells have been extensively investigated, little is known about assembly of the contractile myosin structures at the epithelial adhesion sites. UNC-45A is a cytoskeletal chaperone that is essential for proper folding of NM-II heavy chains and myofilament assembly. We found abundant expression of UNC-45A in human intestinal epithelial cell (IEC) lines and in the epithelial layer of the normal human colon. Interestingly, protein level of UNC-45A was decreased in colonic epithelium of patients with ulcerative colitis. CRISPR/Cas9-mediated knock-out of UNC-45A in HT-29cf8 and SK-CO15 IEC disrupted epithelial barrier integrity, impaired assembly of epithelial adherence and tight junctions and attenuated cell migration. Consistently, decreased UNC-45 expression increased permeability of the Drosophila gut in vivo. The mechanisms underlying barrier disruptive and anti-migratory effects of UNC-45A depletion involved disorganization of the actomyosin bundles at epithelial junctions and the migrating cell edge. Loss of UNC-45A also decreased contractile forces at apical junctions and matrix adhesions. Expression of deletion mutants revealed roles for the myosin binding domain of UNC-45A in controlling IEC junctions and motility. Our findings uncover a novel mechanism that regulates integrity and restitution of the intestinal epithelial barrier, which may be impaired during mucosal inflammation.Peer reviewe
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