274 research outputs found

    Static magnetic order of Sr4_{4}A2_{2}O6_{6}Fe2_{2}As2_{2} (A = Sc and V) revealed by local probes

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    Static magnetic order of quasi two-dimensional FeAs compounds Sr4A2O6-xFe2As2, with A = Sc and V, has been detected by 57Fe Moessbauer and muon spin relaxation ({\mu}SR) spectroscopies. The non-superconducting stoichiometric (x = 0) A = Sc system exhibits a static internal/hyperfine magnetic field both at the 57Fe and {\mu}+ sites, indicating antiferromagnetic order of Fe moments below TN = 35 K with ~ 0.1 Bohr magneton per Fe at T = 2 K. The superconducting and oxygen deficient (x = 0.4) A = V system exhibits a static internal field only at the {\mu}+ site below TN ~ 40 K, indicating static magnetic order of V moments co-existing with superconductivity without freezing of Fe moments. These results suggest that the 42622 FeAs systems belong to the same paradigm with the 1111 and 122 FeAs systems with respect to magnetic behavior of Fe moments.Comment: 4 pages 4 figures: for information, contact [email protected]

    Modelling the influence of radiata pine log variables on structural lumber production

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    We run logit models to explain the variability of Pinus radiata structural lumber in 71 second and third unpruned logs. The response variable was the proportion of lumber with a static modulus of elasticity greater or equal than 8 GPa, pMSG8+, and the explanatory variables were log volume, branch index, largest branch, log internode index, wood basic density, and acoustic velocity. The average pMSG8+ volume was 44,30 % and 36,18 % in the second and third log respectively. Ten models were selected based on meeting statistical assumptions, their goodness of fit, and the statistical significance of their parameters. The best models (R2 - adj. > 0,75) included acoustic velocity (AV) as explanatory variable, which explained 56,25 % of the variability of pMSG8+. Models without AV presented goodness of fit ranging from 0,60 to 0,75 (R2 - adj.), and variables with the highest weight to explain the variability of pMSG8+ were volume, followed by wood basic density, branch index, and largest branch. It is possible to model pMSG8+ from log variables even when acoustic velocity is not available; however, this requires wood basic density models calibrated for the Pinus radiata growing zone

    Synthesis of Poly[(3-(6-(9-anthracenylmethoxy)hexyl)thiophene)-co-(3-(6-bromohexyl)thiophene)] Postfunctionalized from Poly(3-(6-bromohexyl)thiophene): A Comparative Study of the Base Polymer with Its Chlorinated Analogous

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    A synthetic method based on the postfunctionalization of a reactive homopolymer precursor, which allows for the preparation of different copolymers derived from poly(3-alkylthiophene), was studied. Although these groups decrease the solubility of the resultant material, they enable controlling the degree of substitution to obtain a material with improved spectroscopic (absorption and emission) properties making them useful for the fabrication of electronic devices, for example, solar cells and light-emitting diodes. Furthermore, a comparative study of two halogenated (Cl and Br) reactive poly(3-ω-haloalkyl)thiophenes was carried out

    Modelling the influence of radiata pine log variables on structural lumber production

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    We run logit models to explain the variability of Pinus radiata structural lumber in 71 second and third unpruned logs. The response variable was the proportion of lumber with a static modulus of elasticity greater or equal than 8 GPa, pMSG8+, and the explanatory variables were log volume, branch index, largest branch, log internode index, wood basic density, and acoustic velocity. The average pMSG8+ volume was 44,30 % and 36,18 % in the second and third log respectively. Ten models were selected based on meeting statistical assumptions, their goodness of fit, and the statistical significance of their parameters. The best models (R2 - adj. > 0,75) included acoustic velocity (AV) as explanatory variable, which explained 56,25 % of the variability of pMSG8+. Models without AV presented goodness of fit ranging from 0,60 to 0,75 (R2 - adj.), and variables with the highest weight to explain the variability of pMSG8+ were volume, followed by wood basic density, branch index, and largest branch. It is possible to model pMSG8+ from log variables even when acoustic velocity is not available; however, this requires wood basic density models calibrated for the Pinus radiata growing zone

    Análisis de las predicciones climáticas a partir de distintos servicios climáticos para la programación del riego

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    Comunicación presentada al XXXVII Congreso Nacional de Riegos, celebrado en Don Benito del 4 al 6 de Junio de 2019 y organizada por la Asociación Española de Riegos y Drenajes y la Universidad de ExtremaduraEl objetivo del estudio es analizar la precisión de los servicios climáticos disponibles mediante su comparación con los datos reales registrados, y mejorar su estimación para el cálculo de la ETo a la hora de efectuar la programación del riego a corto plazo.Generalitat Valenciana, Consellería de Educación, Investigación, Cultura y Deportes: Proyecto AICO 201

    Magnetic frustration in low-dimensional substructures of hulsite Ni5.15Sn0.85(O2BO3)2

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    CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPERJ - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DO RIO DE JANEIROFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOThis paper presents an extensive study of the structural, magnetic, and thermodynamic properties of the hulsite Ni5.15Sn0.85(O2BO3)(2). The crystal structure of the hulsite has two planar substructures formed by Ni and Sn atoms: one with rectangular configuration and the other with a triangular arrangement. These substructures are linked by the boron ions and by Ni in another site closer to the rectangular arrangement, resulting in a quasi-two-dimensional character. Thus, this system literally adds a new dimension to the study of oxyborates. Our results point to a complex magnetic behavior consistent with these substructures. The planes with rectangular arrangement form a complex magnetic ordering at 180 K (one of the highest magnetic transitions among the oxyborates). The other subsystem, formed by Ni atoms located in a two-dimensional triangular lattice, does not order down to temperatures as low as 3 K. The experimental results suggest a spin-liquid behavior for this subsystem. The magnetic moments of the ions between these planes also freeze at low temperatures. The two magnetic planes coexist as independent subsystems down to the lowest temperatures of our experiments.985110CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPERJ - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DO RIO DE JANEIROFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPERJ - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DO RIO DE JANEIROFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAUL

    Factores asociados al resultado citológico positivo en pruebas de Papanicolau en mujeres atendidas en la Liga peruana de lucha contra el cáncer

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    Objetive: To evaluate the factors associated with a positive cervical cytology result in the Pap smear test in a sample of Peruvian women from Lima, Peru - 2013. Material and Methods: We conducted an analytical cross-sectional study including women from 21 to 64 years and we used the Pap smear test to evaluate cervical cytology. We included sociodemographic and medical history variables obtained from medical records of the patients. We elaborated generalized linear models from Poisson family with robust variances to evaluate the factors associated with positive cytology. The association measure reported was the prevalence ratio (PR) with their respective 95% confidence intervals (95%CI). Results: We analyzed 11110 women with a mean age of 41.5 ± 10.9 years and a prevalence of a positive Pap smear test of 2.8%. In the adjusted model, we found that women between 21 and 30 years old (aPR=1.97; 95%CI:1.30-3.00), 31 to 40 years (aPR=2.56; 95%CI:1.76 -3.72) and 41 to 50 years (aPR=2.16; 95%CI:1.47-3.17), single (aPR=1.41; 95%CI:1.10-1.83), widowed or divorced (aPR=1.90; 95%CI:1.27-2.87), with a sexual life onset before 16 years (aPR=1.30; 95%CI:1.01- 1.68) or between 16 and 19 years (aPR=1.69; 95%CI:1.22-2.36) had a greater prevalence of a positive cervical cytology result. Conclusions: Cervical cancer is a public health problem in Peru, then, identifying the factors associated will allow us to improve screening strategies and prioritize groups at higher risk.Objetivo: Evaluar los factores asociados a un resultado de citología cervical positiva en la prueba de Papanicolau en una muestra de mujeres peruanas en Lima, Perú - 2013. Material y métodos: Se realizó un estudio transversal analítico que incluyó a mujeres con edades entre 21 a 64 años y empleó la prueba de Papanicolaou para evaluar la citología cervical. Se incluyó factores sociodemográficos y antecedentes de la mujer obtenidos de la historia clínica de las pacientes. Se realizaron modelos lineales generalizados de familia Poisson con varianzas robustas para evaluar los factores asociados a la citología positiva. La medida de asociación reportada fue la razón de prevalencia (RP) con sus respectivos intervalos de confianza al 95% (IC95%). Resultados: Se incluyeron a 11110 mujeres en el análisis con una edad media de 41,5±10,9 años y la prevalencia de un resultado positivo en la prueba de Papanicolau fue de 2,8%. En el modelo ajustado, se halló que tener entre 21 a 30 años (RPa=1,97;IC95%:1,30-3,00), 31 a 40 años (RPa=2,56;IC95%:1,76-3,72) y 41 a 50 años (RPa=2,16;IC95%:1,47-3,17), ser soltera (RPa=1,41;IC95%:1,10-1,83), viuda o divorciada (RPa=1,90;IC95%:1,27-2,87), haber tenido inicio de vida sexual antes de los 16 años (RPa=1,30;IC95%:1,01-1,68) o entre los 16 a 19 años (RPa=1,69;IC95%:1,22-2,36) se asoció a una mayor probabilidad de presentar un resultado de citología cervical positivo. Conclusiones: El cáncer de cuello uterino representa un problema de salud pública en Perú, por lo que identificar sus factores asociados es útil para mejorar las estrategias de tamizaje, priorizando grupos de mayor riesgo

    El impacto de la pandemia del COVID-19 en la educación médica: adaptabilidad y experiencia con enseñanza a distancia de la Sociedad Médica Peruano Americana

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    The COVID-19 pandemic had a significant impact on medical care and medical education in Peru.  In response, the Peruvian American Medical Society (PAMS), a charitable medical organization based in the USA, pursued its medical and educational missions in Peru by adopting virtual learning technology. We developed closer collaborative relationships with several medical schools and the Peruvian Association of Medical Schools (ASPEFAM) while offering a faculty panel of twenty-four members to provide lectures and multidisciplinary webinars in Spanish. We conducted 19 webinars including COVID -19 and non-COVID-19 related topics that over the last two years attracted 14,489 participants from 23 countries. They were the foundation for twenty publications in Peruvian medical journals. Our clinical investigations competition was positively received as was our pilot project on research mentorship. The COVID -19 pandemic had a positive effect on the educational mission of PAMS in Peru.La pandemia del COVID-19 tuvo un impacto significativo en el cuidado y la educación médicos en el Perú. En respuesta, la Sociedad Médica Peruano Americana (PAMS), una organización médica benéfica con sede en los EE. UU., adoptó sus misiones médicas y educativas en Perú usando estrategias virtuales. Desarrollamos colaboración con varias facultades de medicina y la Asociación Peruana de Facultades de Medicina (ASPEFAM) y ofrecimos un panel de veinte y cuatro miembros para brindar conferencias y seminarios multidisciplinarios en español. Hicimos 19 seminarios, incluyendo temas relacionados y no relacionados al COVID-19, que en los últimos dos años atrajo a 14 489 participantes de 23 países. Ellas fueron la base de 20 publicaciones en revistas médicas peruanas. Nuestro concurso de investigaciones clínicas y nuestro proyecto piloto de mentoría de investigación fueron recibidos positivamente. La pandemia del COVID-19 tuvo un efecto positivo en la misión educativa de PAMS en Perú
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