Multiparticie aggregation model for dendritic growth applied to experiments on amorphous Co-P alloys

We introduce a multiparticle biased diffusion limited aggregation model for dendritic growth. Its most relevant feature is that it includes the overall effect of strong applied electric fields and therefore applies to nonequilibrium situations. We compare simulations of a two species version of our model to actual experiments on preparation of amorphous Co-P alloys with very good agreement: The model accurately reproduces the dependence of composition, morphology, and growth time of the alloy on the current. We conclude with a discussion of specific predictions and possible generalizations of the model.Supported by DGICyT (Spain) through Grant No. PB92-0248 and by MEC/Fulbright. MJ.B. and J.M.R. acknowledge support from DGICyT (Spain) Grant No. MAT91-0031. Work at Los Alamos is performed under the auspices of the V.S. D.O.E.Publicad

Effect of Hepatitis E Virus RNA Universal Blood Donor Screening, Catalonia, Spain, 2017-2020

Altres ajuts: Banc de Sang i Teixits.Hepatitis E virus (HEV) is the major cause of acute viral hepatitis in several countries in Europe. HEV is acquired mainly by consumption of contaminated pork but can also be transmitted through blood transfusion. HEV infection is usually self-limited but can become persistent in immunocompromised persons. During the fi rst 30 months of HEV RNA universal screening of blood donations in Catalonia, Spain, we identifi ed 151 HEV RNA-positive donations (1/4,341 blood donations). Most infected donors reported consumption of pates and sausages, and 58% were negative for HEV IgM and IgG. All HEV isolates belonged to genotype 3. All infected donors spontaneously resolved the infection, and no neurologic symptoms and reinfections were observed after 1 year of follow-up. Since the implementation of HEV RNA universal screening, no new cases of transfusion-transmitted HEV infection were reported. Our data indicate HEV screening of blood donations provides safer blood for all recipients, especially for immunosuppressed persons

Necesidades de asesoramiento o ayuda de expertos demandadas por el profesorado de educación infantil, primaria y secundaria

This study seeks to find out the advice or consulting needs that preschool, elementary and secondary teachers of our country demand of professional consultants concerning their job as teachers so that information serve as a point of reference for the adoption of appropriate measures to satisfy those needs, favouring the quality of education provided by our educational system. Data are based on a nationwide sample of 1464 teachers and have been analyzed at a global level and according to gender, professional seniority and the educational level where they teach. Results refer to several teaching situations and their implications for the education quality are analyzed.El presente trabajo está dirigido a conocer las necesidades de asesoramiento o ayuda que el profesorado de infantil, primaria y secundaria de nuestro país demanda de profesionales expertos en relación con su trabajo como profesor al objeto de que esta información sirva de referencia en la toma de medidas adecuadas en orden a satisfacer esas necesidades en pro de la calidad de la educación proporcionada por nuestro sistema educativo. Los datos están basados sobre una muestra de 1464 profesores de ámbito nacional y se ha analizado a nivel global y en función del género, de la antigüedad profesional y de la etapa educativa en la que ejercen su docencia. Los resultados hacen referencia a diversas situaciones docentes y sus implicaciones en la calidad educativa han sido analizadas

Multidisciplinary Acoustic Survey PELACUS0313: Preliminary Results on Fish Abundance Estimates and Distribution

The PELACUS 0313 survey was undertook this year on board R/V Miguel Oliver, an oceanographic research stern trawler vessel similar to R/V Thalassa. The survey was characterised by a very bad weather conditions during the first two weeks which did not allow working properly. Moreover, the weather conditions during the rest of survey were almost similar. As a consequence, most of the coastal pelagic fish community remained very close to the coast, thus not accessible to the pelagic gear samplers. (33% of the total acoustic energy – NASC- was unable to be properly allocated into fish species). Outside the coastal area (>90 m depth) main abundance fish species was mackerel with 380.000 tonnes, corresponding to 1.725 million fish. On the contrary, sardine distribution was scarce, and occurred in small schools (probably as a consequence of the bad weather condition), with only 3.343 tonnes corresponding to 54.0 million fish. Age group 2 was the most abundant, which confirms the high abundance found last year at age group 1 of the 2011 cohort

Magnetic and structural-properties of electrodeposited Co1-xPx amorphous ribbons

The specific magnetic moment, coercive force, anisotropy field, and saturation magnetostriction constant have been measured in Co(1-x)P(x) amorphous ribbons with 0.04 less-than-or-equal-to x less-than-or-equal-to 0.27. Differential scanning calorimetry, x-ray diffraction, and transmission electron microscopy analysis have been made in order to study the transition from the amorphous state to the crystalline one. Results suggest that transition takes place when x decreases from 0.19

Role of the oxygen partial pressure in the formation of composite Co-CoO nanoparticles by reactive aggregation

The magnetic properties of diluted films composed of nanocomposite Co-CoO nanoparticles (of ~8 nm diameter) dispersed in a Cu matrix have been investigated. The nanoparticles were formed in an aggregation chamber by sputtering at different Ar/O2 partial pressures (0-0.015). The exchange bias properties appear to be insensitive to the amount of O2 during their formation. However, the temperature dependence of the magnetization, M(T), exhibits two different contributions with relative intensities that correlate with the amount of O2. The magnetic results imply that two types of particles are formed, nanocomposite Co-CoO (determining the exchange bias) and pure CoO, as confirmed by transmission electron microscopy observations. Importantly, as the O2 partial pressure during the sputtering is raised the number of nanocomposite Co-CoO nanoparticles (exhibiting exchange bias properties) is reduced and, consequently, there is an increase in the relative amount of pure, antiferromagnetic CoO particles

Semi-automated creation of accurate FEM meshes of heritage masonry walls from point cloud data

The structural analysis of buildings requires accurate spatial models. Additionally, pathologies such as settlement-induced damages are paramount in the assessment of heritage assets. This spatial information is used as a basis for Finite Element Method (FEM) meshes to evaluate the stability of the structure. Traditional data acquisition approaches rely on manual measurements which are labor intensive and error prone. Therefore, major simplifications are made to document structures efficiently. The goal of this research is to provide faster and more accurate procedures to capture the spatial information required by a FEM. This paper presents a semi-automated approach to create accurate models of complex heritage buildings for the purpose of structural analysis. By employing non-destructive techniques such as terrestrial laser scanning and photogrammetry, a complex mesh of the structure is created. Also, a methodology is proposed to capture crack information. A stepwise approach is elaborated to illustrate how the spatial information is adapted towards a FEM mesh. The results show a significant difference between the geometry our model and a traditional wire- frame model. Not only does accurate modelling result in deviating loads, it also affects the behavior of the object. Through the proposed approach, experts can develop highly accurate FEM meshes to assess the stability of the structure up to as-built conditionsPostprint (published version

Multiparticle Biased DLA with surface diffusion: a comprehensive model of electrodeposition

We present a complete study of the Multiparticle Biased Diffusion-Limited Aggregation (MBDLA) model supplemented with surface difussion (SD), focusing on the relevance and effects of the latter transport mechanism. By comparing different algorithms, we show that MBDLA+SD is a very good qualitative model for electrodeposition in practically all the range of current intensities {\em provided} one introduces SD in the model in the proper fashion: We have found that the correct procedure involves simultaneous bulk diffusion and SD, introducing a time scale arising from the ratio of the rates of both processes. We discuss in detail the different morphologies obtained and compare them to the available experimental data with very satisfactory results. We also characterize the aggregates thus obtained by means of the dynamic scaling exponents of the interface height, allowing us to distinguish several regimes in the mentioned interface growth. Our asymptotic scaling exponents are again in good agreement with recent experiments. We conclude by discussing a global picture of the influence and consequences of SD in electrodeposition.Comment: 15 pages, 20 figures, accepted for publication in Physical Review