Regular or random: a discussion on SPH initial particle distribution

Smoothed Particle Hydrodynamics (SPH) has been used to model a variety of objects and for a number of applications in engineering and science. These have ranged from astrophysicstofluidandsolidmechanicsproblems. Muchresearchhasbeendedicatedtoforming a better understanding of the SPH method. As a consequence, new numerical techniques have been developed in order to overcome some of its difficulties and limitations. Nonetheless, there is still a gap in information concerning the impact of the initial particle distribution on the effectiveness of the SPH method. With this in mind, a review of existing recommendations for SPH initial configurations has been conducted in this paper. In addition to this, a numerical exampleispresentedwhichisbasedontheclassical2-Dliddrivencavityproblem,whereinthe upperboundaryexertsahorizontalshearforceonthefluidinsidethecavity. Thevelocityofthe lid is v = 10−3 m/s and the cavity is square with length l = 1x10−3 m. The fluid was modelled with a density ρ = 1000 kg/m3, a viscosity µ = 10−3 kg/ms) (Re = 1). These parameters were held constant for all consequent comparisons. The number of particles is varied from (20 × 20) to (80 × 80). The initial distribution is modelled in three different ways: (i) regular, (ii) pseudo-random (with a 30% random deviation from the regular grid) and (iii) fully random. Theeffectivenessofeachinitialparticledistributionisassessedaccordingtothefieldvelocities and horizontal and vertical centreline velocity profiles. The impact of the initial particle distribution is highlighted and compared against a reference CFD result, and recommendations and conclusions are drawn for the SPH method

Screening of herbicides in grain legumes: pre-emergence herbicides in faba beans

Ante la escasez de herbicidas autorizados en leguminosas, se realizaron dos ensayos en habas con 10 herbicidas elegidos por estar autorizados en otras leguminosas o en otros países. Ninguno de los productos resultó totalmente eficaz y selectivo. Algunos de los herbicidas de preemergencia autorizados en España en habas para grano resultaron menos eficaces contra las malas hierbas y produjeron mayor fitotoxicidad que otros no autorizados. Así mismo, productos autorizados en Francia resultaron fitotóxicos en nuestras condiciones. Los mejores resultados seguido de ixosaben y aclonifen. Sin embargo será necesario ajustar dosis y buscar otras alternativas, como combinaciones de productos o estrategias de control para mejorar las eficacias y la selectividad, y sobre todo elegir los productos en función de las especies de malas hierbas dominantes en cada finca.Faced with a shortage of herbicides in legumes, two trials were conducted in faba beans to evaluate 10 herbicides elected by being authorized in other legumes or in other countries. None of the product was completely effective and selective. Some of the pre-emergence herbicides authorized in Spain for grain faba beans were less effective against weeds and produced more phytotoxicity than others not authorized. Likewise, products authorized in France turned out quite phytotoxic in our conditions. The best results were obtained with metribuzin by its effective weed control and low phytotoxicity, followed by ixosaben and aclonifen. However it will be necessary to adjust dose, to look for other alternatives, such as combinations of products or control strategies to improve effectiveness and selectivity, and above all choose the products depending on the species of dominant weeds in each farm

Salvage therapy for multidrug-resistant tuberculosis

AbstractTreatment of multidrug-resistant tuberculosis (MDR-TB), defined as Mycobacterium tuberculosis resistant to both isoniazid and rifampicin, is challenging under the best of circumstances, and particularly in resource-limited settings. For patients who remain persistently sputum-culture-positive despite therapy with second-line TB drugs, treatment options are limited, especially if disease is too advanced for resective surgery. Salvage therapy refers to the design of a regimen combining new and previously used drugs in a final effort to attain sputum conversion before declaring treatment to have failed. We retrospectively evaluated the outcomes of salvage therapy in 213 Peruvian patients. Salvage regimens included a median of two new drugs (range 1–6) and nine (range 5–13) total (new plus previously used) drugs. The most frequently used new drug was moxifloxacin, followed by capreomycin, amoxicillin-clavulanate, kanamycin and clarithromycin. Culture conversion occurred in 65 (30.5%) patients. Salvage regimens that included moxifloxacin were significantly more likely to be followed by culture conversion (OR 2.2; p 0.02). Later-generation fluoroquinolones such as moxifloxacin should be used in salvage therapy but also in the initial treatment of MDR-TB, if the best clinical strategy is to use the most effective drugs when the patient has the best chance for cure. New TB drugs are most likely to be initially used in salvage patients, in conditions similar to those described here. Close bacteriological monitoring of these patients will be essential, as useful information about the best way to use these new drugs can be gained from analysis of salvage therapy cohorts

Addressing present challenges in the life-cycle of wetlands management to successfully integrate sustainability and good governance

The assessment of management effectiveness during the whole life-cycle process of protected areas (PAs) has become increasingly important, due to the lack of holistic background assessment work on management processes leading to a deeper knowledge of sustainable development (SD) principles. This paper aims to serve as a practical guide through a gradation model of integrated protected area management (IPAM) by carrying out an exhaustive trans-dimensional assessment of management effectiveness, identifying a critical field of activities and developing a framework mix of strategic recommendations leading to the implementation of an effective planning process. Our results could aid in the prioritisation of key decisions towards a more in-depth understanding of how to set up a balanced IPAM, as well as to enable managers and decision-makers to focus on activities that can further pre-established aims and reach the goal of five-dimensional sustainability in terms of SD and good governance

Pérdidas de fruto y movilización de semillas en olea europaea var. Sylvestris brot. (oleaceae)

Se analizan varios aspectos de la biología de reproducción del acebuche [Olea europaea var. sylvestris Brot. (Oleaceae)] relacionados con la dispersión de semillas. Se compara el éxito de remoción en dos habitat -uno en dos temporadas- y se analizan las similitudes y diferencias en las causas de pérdidas de frutos por agentes bióticos y abióticos. En general, el esfuerzo de producción de fruto fue poco recompensado, ya que el éxito de remoción fue bajo. Las pérdidas totales de fruto variaron considerablemente entre años, pero aparentemente no limitaron la dispersión de semillas. Los agentes abióticos causaron más pérdidas que los bió- ticos. Al final de la temporada permanecían muchos frutos en las ramas, lo que sugiere que la cantidad de dispersantes fue limitante para el éxito de remoción. La importancia relativa de la remoción y de cada tipo de pérdida permaneció constante entre habitat y tendió a mantenerse entre individuos. En conclusión, aunque el porcentaje de remoción fue bajo, los resultados sugieren que el éxito de la función de fructificación de los acebuches en estas parcelas dependió fundamentalmente de la acción de los dispersantes

El efecto de exposición en el patrón sedimen- tario del sector submareal de tres playas en la Ría de Muros y Noia (NO de España)

En este trabajo se presenta la comparación de los sedimentos superficiales de la plataforma proximal de tres complejos playeros situados en las inmediaciones de la embocadura de la Ría de Muros y Noia. En cada uno de ellos, se han identificado las distintas poblaciones sedimentarias en función de los análisis granulométricos realizados. La aplicación de un análisis estadístico de componentes principales a las fracciones granulométricas, contenido en carbonatos y materia orgánica, ha permitido diferenciar poblaciones de muestras y la interpretación sedimentaria de las mismas. Las diferencias observadas en la distribución de las poblaciones sedimentarias de los tres complejos estudiados son una consecuencia del grado de exposición de cada complejo al oleaje dominante y de la presencia de afloramientos rocosos sumergidos que ejercen un efecto barrera.The subaquatic sediments from the inner continental shelf of three beach systems located in the surrondings of Ría de Muros y Noia mouth are compared. Different sedimentary populations have been stablished according to the granulometric distribution from each system. The grain-size distribution, carbonate and organic matter content have been compared by means of a principal component analysis. The results allow the identification of different populations as well as their sedimentary significance. The observed differences between the sedimentary populations from each system are explained as a consequence of their grade of exposure towards the dominant waves and the presence of subaquatic rocks, which introduce a barrier effect

Hydrogen passivation of boron acceptors in as-grown boron-doped CVD diamond epilayers

A homoepitaxial boron-doped diamond single layer is investigated by means of Fourier transformed infrared spectroscopy (FTIR) and cathodoluminescence (CL). Both techniques are shown to be complementary. μ-FTIR mapping allows to determine the location of active boron while CL allows discernability between passivation and compensation. Hydrogen incorporation during chemical vapour deposition (CVD) growth is revealed to passivate boron acceptors. The obtained results highlight that plasma etching can induce a dissociation of B–H centres.4 page