510 research outputs found
The mass of the white dwarf in YY Dra (=DO Dra): Dynamical measurement and comparative study with X-ray estimates
No full textWe present a dynamical study of the intermediate polar cataclysmic variable YY Dra based on time-series observations in the K band, where the donor star is known to be the major flux contributor. We covered the 3.97-h orbital cycle with 44 spectra taken between 2020 and 2022 and two epochs of photometry observed in 2021 March and May. One of the light curves was simultaneously obtained with spectroscopy to better account for the effects of irradiation of the donor star and the presence of accretion light. From the spectroscopy, we derived the radial velocity curve of the donor star metallic absorption lines, constrained its spectral type to M0.5–M3.5 with no measurable changes in the effective temperature between the irradiated and non-irradiated hemispheres of the star, and measured its projected rotational velocity vrot sin i = 103 ± 2 km s−1. Through simultaneous modelling of the radial velocity and light curves, we derived values for the radial velocity semi-amplitude of the donor star, km s−1, the donor to white dwarf mass ratio, q = M2/M1 = 0.62 ± 0.02, and the orbital inclination, i = 42°−1°+2°. These binary parameters yield dynamical masses of and (68 per cent confidence level). As found for the intermediate polars GK Per and XY Ari, the white dwarf dynamical mass in YY Dra significantly differs from several estimates obtained by modelling the X-ray spectral continuum
A simple method for screening bacterial colonies for mutagenized sites in plasmid DNA
No full textBecause of the multiple-step process that is involved in the detection of mutagenized restriction enzyme sites in plasmid DNA, a simple and accurate method was developed to analyse the plasmid DNA of site-directed mutagenesis experiments from bacterial colonies. The desired mutated part is located between the Eco RI restriction site on pUC19. Two mutagenic primers were designed to replace only one nucleotide on segments A and B of the bi-segmented genome of infectious bursal disease virus (IBDV). Two restriction sites were created for those mutations in each segment, Fsp I and Dra I, respectively. Following a protocol from the site-directed mutagenesis kit, the mutated plasmids were used to transform, and were propagated and maintained in DH5 alpha competent cells. Colonies were picked from the master plate, and used as DNA template for PCR. The PCR technique included the design of two pairs of primers, one for each segment, which were to amplify a region up to 1000 bp. Samples were pre-incubated for 3 min at 94 degrees C to induce bacterial lysis before starting the nucleic acid amplification. The PCR products 918 bp from segment A and 650 bp from segment B were digested with Fsp I and Dra I at 37 degrees C for 1 h. Products were resolved on 0.9% agarose gel which contained ethidium bromide. This method is simpler, faster and more accurate than the traditional method of mini-prep plasmid isolation and colony blot hybridization to identify the mutated plasmids
HLA-DRA variants predict penicillin allergy in genome-wide fine-mapping genotyping
No full textBACKGROUND:
Immediate reactions to β-lactams are the most common causes of anaphylactic reactions and can be life-threatening. The few known genetic factors influencing these reactions suggest a link with atopy and inflammation.
OBJECTIVE:
We performed a fine-mapping genome-wide association study of the genetic predictors of β-lactam allergy to better understand the underlying mechanisms.
METHODS:
We studied 387 patients with immediate allergic reactions to β-lactams and 1124 paired control subjects from Spain. We replicated the results in 299 patients and 362 paired control subjects from Italy.
RESULTS:
We found significant associations with the single nucleotide polymorphisms rs4958427 of ZNF300 (c.64-471G>A, P = 9.9 × 10(-9)), rs17612 of C5 (c.4311A>C [p.Glu1437Asp], P = 7.5 × 10(-7)), rs7754768 and rs9268832 of the HLA-DRA | HLA-DRB5 interregion (P = 1.6 × 10(-6) and 4.9 × 10(-6)), and rs7192 of HLA-DRA (c.724T>G [p.Leu242Val], P = 7.4 × 10(-6)) in an allelic model, with similar results in an additive model. Single nucleotide polymorphisms of HLA-DRA and ZNF300 predicted skin test positivity to amoxicillin and other penicillins but not to cephalosporins. A haplotype block in HLA-DRA and the HLA-DRA | HLA-DRB5 interregion encompassed a motif involved in balanced expression of the α- and β-chains of MHC class II, whereas rs7192 was predicted to influence α-chain conformation. HLA-DRA rs7192 and rs8084 were significantly associated with allergy to penicillins and amoxicillin (P = 6.0 × 10(-4) and P = 4.0 × 10(-4), respectively) but not to cephalosporins in the replication study.
CONCLUSIONS:
Gene variants of HLA-DRA and the HLA-DRA | HLA-DRB5 interregion were significant predictors of allergy to penicillins but not to cephalosporins. These data suggest complex gene-environment interactions in which genetic susceptibility of HLA type 2 antigen presentation plays a central role.
Copyright © 2014 American Academy of Allergy, Asthma & Immunology. All rights reserved.
KEYWORDS:
Drug allergy; HLA-DRA; amoxicillin; anaphylaxis; genome-wide association; immediate-type reactions; penicillins; β-lactam
A utilização de ambientes virtuais para a aprendizagem colaborativa no ensino fundamental
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia de Produção.Com a crescente evolução das tecnologias da comunicação, inúmeros são os recursos hoje disponíveis para a construção de um ambiente para a aprendizagem colaborativa. Este trabalho analisa as características de uma comunidade virtual, que complementa a aprendizagem presencial para o ensino fundamental de 5ª a 8ª séries. Dentro desta nova realidade muda a postura do professor, que já não se limita mais a um mero transmissor do conhecimento, mas um guia, um mediador, co-parceiro do aluno, buscando e interpretando de forma crítica as informações. E o educando passa a ser um participante ativo neste processo de aprendizagem, interagindo e tendo um senso de posse dos objetivos do aprendizado. A partir dos resultados obtidos através da pesquisa de campo, são analisadas as dificuldades enfrentadas por educadores e educandos na utilização de um ambiente colaborativo, bem como os benefícios que estas práticas trazem para a educação. Consequentemente são apresentadas características de ferramentas que constituem um ambiente de aprendizagem colaborativo adequado, sempre tendo em mente que hoje educar e aprender é bem mais do que transmitir e receber informação:écomunicar informação e gerar conhecimento
Produção/reprodução e transformação do comportamento alcoolista nos contextos culturais da família e do trabalho /
No full textDissertação (Mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências da Saúde.A presente dissertação de mestrado trata de uma investigação realizada a partir dos resultados obtidos na Prática Assistencial, quando foi oferecida, a três famílias de servidores alcoolistas, uma modalidade de assistência de enfermagem pautada na Teoria Sistêmica de Família e na Teoria de Leininger. Buscando ampliar e complementar os dados obtidos, foi elaborado um projeto que deu origem a este estudo, o qual tem por objetivos: analisar as influências do contexto do trabalho na produção/reprodução e transformação do comportamento alcoolista; analisar os nexos entre a produção/reprodução e transformação do comportamento alcoolista no contexto do trabalho e da família e propor alternativas para a transformação do comportamento alcoolista no trabalho, mediante as potencialidades identificadas na família e no trabalho. Este é um estudo exploratório, qualitativo, realizado com três funcionários alcoolistas da UFSM (Universidade Federal de Santa Maria) vinculados às famílias anteriormente pesquisadas. A metodologia constitui-se na análise de fichas funcionais, observação participante no ambiente de trabalho e entrevista com chefias, quando necessário. Após a etapa de coleta de dados, foi possível analisar os nexos entre o comportamento alcoolista na família e o comportamento alcoolista no trabalho. Identificar a produção/reprodução do comportamento alcoolista no contexto do trabalho viabilizou a sinalização de uma proposta de transformação, para a qual aponto indicadores de mudanças; e também reconheço a necessidade de espaços para desenvolver um trabalho integrado entre os serviços que tratam o alcoolismo, principalmente ao nível institucional, no qual me incluo, na tentativa de buscar outras maneiras de investir em mudanças gradativas do comportamento alcoolista
Comité editorial
No full textAutoridades
Universidad Nacional de Córdoba
Facultad de Ciencias Químicas
Decano Dr. Marcelo M. MariscalVicedecana Dra. Silvia Correa
Editor Responsable
Dra. Eva Virginia Acosta Rodríguez. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Secretaria de Ciencia y Tecnología. Contacto: [email protected]
Área Química Básica: Dra. Verónica Brunetti. Departamento de Fisicoquímica (FCQ)Dr. Mariano Teruel. Departamento de Fisicoquímica (FCQ)Dra. Mariana A. Fernández. Departamento de Química Orgánica (FCQ)Dr. Martín E. Zoloff Michoff. Departamento de Química Teórica y Computacional (FCQ)
Área Ciencias Biomédicas: Dra. Virginia Rivero. Departamento de Bioquímica Clínica (FCQ)
Dra. Gladys Granero Departamento de Ciencias Farmacéuticas (FCQ)Dr. Eduardo Garbarino Pico. Departamento de Química Biológica "Ranwel Caputto" (FCQ)Dra. Mariela Pérez. Departamento de Farmacología "Otto Orsingher" (FCQ)
Subcomité de asesoramiento, edición y carga digitalLic. María Laura Campos. Prosecretaria de Comunicación (FCQ). Lic. Javier Lanza. Biblioteca Dr. Aníbal A Sanguinetti. Director. Responsable RDU (FCQ)Lic. María Cristina Villagra (FCQ)Lic. Ana Laura Peirone (FCQ
Modelo de posicionamiento para el comercio electrónico de productos : un caso
No full textTesis-(Maestría en Gestión de la Innovación Tecnológica
Dancing national Identity: The evolution of meta-narratives in Colombian and Filipino Folk Dance
No full textThe Philippines and Colombia share a history of colonial conquest from the same country, Spain. This shared history has influenced the ways in which folk dance has developed. Both countries have a wide folk repertoire, some of which reflects the different ways in which Spanish source material has been processed, adapted, and fused with local material to represent ways in which the past is remembered. Despite the apparent disparity, two dances in particular, the Cariñosa in the Philippines, and the Bambuco in Colombia, share similar features in terms of their choreographic material and narratives. This article explores several meta-narratives in both sets of dances, and the politics of memory behind them, through an interdisciplinary approach, intertwining cultural representation and choreographic politics. Included in this comparative exploration are the choices towards reflecting local identities through folk dance and some of the implications of these representations in both physical and political terms
Dancing national Identity: The evolution of meta-narratives in Colombian and Filipino Folk Dance
No full textThe Philippines and Colombia share a history of colonial conquest from the same country, Spain. This shared history has influenced the ways in which folk dance has developed. Both countries have a wide folk repertoire, some of which reflects the different ways in which Spanish source material has been processed, adapted, and fused with local material to represent ways in which the past is remembered.
Despite the apparent disparity, two dances in particular, the Cariñosa in the Philippines, and the Bambuco in Colombia, share similar features in terms of their choreographic material and narratives. This article explores several meta-narratives in both sets of dances, and the politics of memory behind them, through an interdisciplinary approach, intertwining cultural representation and choreographic politics. Included in this comparative exploration are the choices towards reflecting local identities through folk dance and some of the implications of these representations in both physical and political terms
Drag Reduction in Turbulent Flows by Polymers and Surfactants: An Experimental Study Into the Mechanisms of Drag Reduction by Additives
No full textIn 1949, Toms (Toms B.A., (1949, 1977)) observed that small amounts of a drag reducing agent (DRA) could cause a considerable drag reduction in turbulent pipe flow. In application of polymer enhanced oil recovery, degradation of polymers in the supply lead could cause clogging. It was, however observed that surfactants at sufficiently high concentration also showed drag reduction without the problem clogging. A DRA reduces the energy loss by friction and unstable flow, thus improving injection throughput with the same pressure pump and thereby reducing the exergetic pumping costs. This study investigates experimentally the drag reducing capacity of surfactants and compares it to the drag reducing capacity of polymers.For the experiment, a set-up consisting of a pump, a coiled test tube with a length of 1.48 m and an inner diameter of 0.5 mm and pressure gauges is built. The diameter of the coil is 12.5 cm. We use a pump capable of injection up to 200 ml/min. The pressure drop is measured between the entrance and end of the tube. The injection rate is varied between 1 and 200 ml/min, roughly corresponding to Reynolds numbers between 50 and 10,000. The additives are dissolved in brine with a 33,000 ppm salt concentration. The viscosity of the solution is dependent on the concentration of the DRA. The ratio of the measured pressure drop with only brine and the pressure drop with the DRA solution was used to calculate the drag reduction (DR) factor, as from a technical point of view we are only interested whether adding DRA reduces the drag with respect to the original brine solution. From an academic point of view, we remark that for low concentrations the viscosity enhancement due to the presence of the DRA is negligible. As polymers we use xanthan (a biopolymer), and a synthetic emulsion polymer based on polyacrylamide. Maximum DR factors are 23% for xanthan at 90ppm and 32% at 90ppm for the synthetic emulsion polymer. DR only occurs at turbulent conditions.Three types of surfactants, each from a different branch of surfactants are used in this study. The surfactants used are AOS {훼-Olefin Sulfonate}, CTAB {hexadeCylTrimethylAmmonium Bromide} and APG {Alkyl PolyGlucoside} which are a cationic, anionic and a nonionic surfactant respectively. The surfactants did not show any DR at (for DRA applications) high concentrations up to 20.000ppm. Addition of Sodium Salicylate (NaSaL) to CTAB with a 1:1 ratio led to a maximum DR of 33% at 2500 ppm concentration.Several pressure gauges have been installed along the test tube in order to observe how the pressure drops along the tube, how the DRAs affect these pressure drops and at what location of the test tube the DR factor is the highest. It is found that xanthan has the same DR factor at each location of the test tube, the emulsion polymer has a decreasing DR factor as the distance from the inlet of the test tube increases and the CTAB+NaSaL DRA has an increasing DR factor as the distance from the inlet increases.The DRAs are sheared using a constriction in the flow loop while the degradation is monitored. It is observed that xanthan is less susceptible to degradation in comparison to the emulsion polymer due to its more rigid chemical structure. But xanthan and the emulsion polymer would be inefficient to use in looped flow systems as they are affected by degradation. The CTAB+NaSaL DRA on the other hand shows no degradation meaning that the micellar rod-like structures that give the DR effect are being repaired when the shear force is being removed. However, for surfactants higher concentrations (1000-2500 ppm) are required.Petroleum Engineering and Geo-science
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