519 research outputs found

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

    Get PDF
    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

    Biomimetic electrochemical sensor integrated in flexible polymeric devices for cancer diagnosis

    Get PDF
    The authors gratefully acknowledge to the project IBEROS, Instituto de Bioingeniería en Red para el Envejecimiento Saludable, PROGRAMA INTERREG 2014-2020, reference POCTEP/0245_IBEROS_1_E and the financial support to CANCER Project through Norte 2020 – Programa Operacional Regional do Norte, reference NORTE-01-0145-FEDER-000029.info:eu-repo/semantics/publishedVersio

    Relaciones entre las dimensiones de las actitudes hacia las matemáticas en futuros maestros

    Get PDF
    En este trabajo se estudian las relaciones entre distintas dimensiones de las actitudes hacia las Matemáticas de los estudiantes del Grado en Educación Primaria de la Universidad de A Coruña del 1.er y 3.er curso recogidas durante tres años académicos consecutivos. Para ello se aplica el cuestionario de actitudes PAC de Naya-Riveiro, Soneira, Mato y Torre (2014) con una fiabilidad Alfa de Cronbach de 0.921 a una muestra de 308 estudiantes. El instrumento está formado por 19 ítems con cinco opciones de respuesta tipo Likert y tres dimensiones que miden el autoconcepto, la percepción que tiene el alumno de su profesor y el agrado hacia las Matemáticas. Los resultados muestran que existe una relación monótona creciente entre las distintas dimensiones de las actitudes en ambos cursos y que éstas se mantienen de un curso a otro

    Fabrication and deposition of copper and copper oxide nanoparticles by laser ablation in open air

    Get PDF
    The proximity of the “post-antibiotic era”, where infections and minor injuries could be a cause of death, there are urges to seek an alternative for the cure of infectious diseases. Copper nanoparticles and their huge potential as a bactericidal agent could be a solution. In this work, Cu and Cu oxide nanoparticles were synthesized by laser ablation in open air and in argon atmosphere using 532 and 1064 nm radiation generated by nanosecond and picosecond Nd:YVO4 lasers, respectively, to be directly deposited onto Ti substrates. Size, morphology, composition and the crystalline structure of the produced nanoparticles have been studied by the means of field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), the energy dispersive spectroscopy of X-rays (EDS), selected area electron diffraction (SAED) and X-ray diffraction (XRD). The UV-VIS absorbance of the thin layer of nanoparticles was also measured, and the antibacterial capacity of the obtained deposits tested against Staphylococcus aureus. The obtained deposits consisted of porous coatings composed of copper and copper oxide nanoparticles interconnected to form chain-like aggregates. The use of the argon atmosphere contributed to reduce significantly the formation of Cu oxide species. The synthesized and deposited nanoparticles exhibited an inhibitory effect upon S. aureus.Peer ReviewedPostprint (published version

    ICES. 2021. Working Group on Southern Horse Mackerel Anchovy and Sardine (WGHANSA).

    Get PDF
    The ICES Working Group on Southern horse mackerel, anchovy and sardine (WGHANSA) assessed the status of anchovy in Atlantic Iberian waters (ane.27.9a; western and southern components) and horse mackerel in Atlantic Iberian waters (hom.27.9a) in the May meeting and of anchovy in Bay of Biscay (ane.27.8), sardine in southern Celtic Seas and the English Channel (pil.27.7), sardine in Bay of Biscay (pil.27.8abd) and sardine in Cantabrian Sea and Atlantic Iberian waters (pil.27.8c9a) in the November meeting. In addition, to answer a special request from Portugal and Spain, in May the working group updated the assessment of sardine in Atlantic Iberian waters (pil.27.8c9a) based on the most recent data available and included as catch scenarios, the harvest control rule evaluated in the Workshop for the evaluation of the Iberian sardine harvest control rules (WKSARHCR 2021). Deviations from the stock annex caused by missing surveys and deteriorated catch data due to the Covid-19 were described and sensitivity analyses of their impact were provided whenever possibl

    Preventing failure propagation in steel truss bridges

    Full text link
    [EN] Metal and steel truss bridges are essential for transportation networks worldwide but are vulnerable to collapse due to deterioration and increasing traffic loads, par-ticularly for ageing structures. Several bridge collapses, such as the Seongsu bridge (South Korea, 1994), I-35 bridge (USA, 2007), and Chauras bridge (India, 2012), have highlighted the need to develop accurate robustness assessment strategies and efficient mitigation of collapse risks. This paper summarizes results of experi-mental and computational studies for a steel riveted bridge with a truss-type struc-ture. The experimental component presented involves unique tests to be performed on a 21 m full-scale bridge span subjected to the failure of different elements under laboratory conditions. The paper then presents a first approach to explore different damage and failure scenarios for steel truss bridges, which will assist in defining data collection strategies for optimised monitoring and developing data analysis methods for real-time diagnosis of ageing bridges. With this, the paper contributes to avoiding progressive collapses and presents a framework, developed as part of an ongoing project, to identify vulnerable zones for prioritising monitoring systems that anticipate failure propagation and prevent collapse. The framework is based on a systematic analysis of past bridge failures and simulations of carefully designed generic cases.Sánchez-Rodríguez, A.; López, S.; Makoond, NC.; Buitrago, M.; Riveiro, B.; Adam, JM. (2023). Preventing failure propagation in steel truss bridges. Ernst & Sohn, Wiley Online Library. 2206-2213. https://doi.org/10.1002/cepa.23772206221

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

    Get PDF
    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

    Helping the family carers of Alzheimer's patients: from theory... to practice: a preliminary study

    Get PDF
    [Abstract] Alzheimer's disease (AD) represents one of the most important health issues in the western world. The ongoing care that the AD patient requires typically causes high stress levels, fatigue, irritation and depression in the caregiver, as well as socio-economical problems. The current study aimed to introduce a support program for carers of AD patients, in order to improve their quality of life. A Questionnaire for Carers and an Anxiety State Feature Questionnaire (STAI) was used to assess the carers. Results showed an overall improvement in the carers' health. Their subjective wellbeing increased, and though their situation had not changed, they nevertheless described feeling les s trapped. It can be concluded that possibly the mere fact that the carers feel that they have help available is enough to endorse the value of the program
    corecore