384 research outputs found

    Effective Maxwell's equations in general periodic microstructures

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    We study the time harmonic Maxwell equations in a meta-material consisting of perfect conductors and void space. The meta-material is assumed to be periodic with period η>0\eta > 0; we study the behaviour of solutions (Eη,Hη)(E^{\eta}, H^{\eta}) in the limit η0\eta \to 0 and derive an effective system. In geometries with a non-trivial topology, the limit system implies that certain components of the effective fields vanish. We identify the corresponding effective system and can predict, from topological properties of the meta-material, whether or not it permits the propagation of waves

    A avaliação da produtividade em pesquisa na Educação Física: reflexões sobre algumas limitações dos indicadores bibliométricos

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    The aim was examine the limitations of bibliometric evaluation based on citation, and discuss the influence of this form of assessment of knowledge production in Physical Education, especially in post-graduate programs. Thus, we made a description of the main limitations of the bibliometric indicators (impact factor and h-index) used in Brazil to assess the production in research. Journals and researchers may be changing their behavior to increase their impact/score in the evaluation system, with consequences like the gap between what is produced in the area of Physical Education and its academic and social relevance. We consider that the forms of assessment need to be (re)designed as well as the quality of scientific publications more productively considered. We believe it is crucial a greater involvement of the academic and scientific community in discussions about the consequences of using these citation-based indicators to the area of Physical Education.Nuestro objetivo fue analizar las limitaciones de la evaluación bibliométrica basadas en el uso de la citación y reflexionar sobre la influencia de este tipo de evaluación de la producción de conocimiento en el área de Educación Física, sobre todo en la posgrado. Describimos las principales limitaciones de los indicadores (factor de impacto y índice h) utilizados en Brasil para evaluar la investigación cientifica. Revistas y investigadores pueden cambiar su comportamiento para incrementar su impacto en el sistema de evaluación, con consecuencias como la brecha entre lo conocimiento producido en la área y su relevancia social y académica. Las formas de evaluación deben ser (re)pensadas, por sus efectos sobre la calidad de las publicaciones. Consideramos que es esencial una mayor participación de la comunidad académica y científica en los debates sobre las consecuencias que el uso de estos indicadores bibliométricos pueden aportar al área de Educación Física.Nosso objetivo foi analisar as limitações da avaliação bibliométrica baseada no uso da citação; e refletir sobre a influência desta forma de avaliação da produção de conhecimento na área da Educação Física, especialmente na pós-graduação. Fizemos uma descrição das principais limitações dos indicadores (fator de impacto e índice h) utilizados no Brasil para avaliação da produção de pesquisa. Revistas e pesquisadores podem estar mudando seu comportamento para aumentar seu impacto no sistema de avaliação, com consequências como o distanciamento entre o que é produzido na área de conhecimento e sua relevância social e acadêmica. As formas de avaliação precisam ser (re)pensadas de forma mais profícua, quanto aos seus efeitos sobre a qualidade das publicações científicas. Consideramos fundamental um maior envolvimento por parte da comunidade acadêmica e científica, em discussões sobre as consequências que o uso desses indicadores baseados em citação pode trazer para a área da Educação Física

    Giant Amazonian fish pirarucu (Arapaima gigas): Its viscera as a source of thermostable trypsin

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    A trypsin was purified from pyloric caeca of pirarucu (Arapaima gigas). the effect of metal ions and protease inhibitors on its activity and its physicochemical and kinetic properties, as well its N-terminal sequence, were determined. A single band (28.0 kDa) was observed by SDS-PAGE. Optimum pH and temperature were 9.0 and 65 degrees C, respectively. the enzyme was stable after incubation for 30 min in a wide pH range (6.0-11.5) and at 55 degrees C. the kinetic parameters K-m, k(cat) and k(cat)/K-m were 0.47 +/- 0.042 mM, 1.33 s(-1) and 2.82 s(-1) mM(-1), respectively, using BApNA as substrate. This activity was shown to be very sensitive to some metal ions, such as Fe2+, Hg2+, Zn2+, Al3+, Pb2+, and was highly inhibited by trypsin inhibitors. the trypsin N-terminal sequence IVGGYECPRNSVPYQ was found. the features of this alkaline peptidase suggest that it may have potential for industrial applications (e.g. food and detergent industries). (C) 2012 Elsevier B.V. All rights reserved.Financiadora de Estudos e Projetos (FINEP/RECAR-CINE)Ministerio da Aquicultura e Pesca (MAP)Empresa brasileira de pesquisa agropecuaria (Embrapa)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundacao de Apoio a Ciencia e Tecnologia do Estado de Pernambuco (FACEPE)Petroleo do Brasil S/A (PETROBRAS)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Univ Fed Pernambuco, Lab Enzimol LABENZ, Dept Bioquim, BR-50670420 Recife, PE, BrazilUniv Fed Pernambuco, LIKA, BR-50670420 Recife, PE, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Dept Biofis, BR-04044020 São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Dept Biofis, BR-04044020 São Paulo, BrazilWeb of Scienc

    Thiazide diuretics alone or in combination with a potassium-sparing diuretic on blood pressure-lowering in patients with primary hypertension : protocol for a systematic review and network meta-analysis

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    Background The use of thiazide (T) diuretics for the treatment of hypertension may be associated with adverse metabolic effects, which can be minimized by combining thiazides with potassium-sparing (PS) diuretics. The additional blood pressure (BP)-lowering effect provided by the addition of a PS diuretic is unclear. Due to a large number of drugs in the T diuretics class, and the possible difference between them, there is a need to identify the best available evidence for health decision-making. This systematic review with network meta-analysis aims to compare the antihypertensive efficacy of T diuretics alone or in combination with a PS diuretic in patients with primary hypertension, as well as the safety of such drugs through the measurement of drug-related adverse events. Methods A comprehensive electronic search will be conducted in six electronic bibliographic databases (PubMed/MEDLINE, Cochrane Library, Embase, Web of Science, Scopus, Lilacs), a registration database (ClinicalTrials.gov), and Educational Resources Information Center (ERIC [ProQuest]), published from inception to the date of the search. The search will be updated towards the end of the review. A hand search of the reference sections of the included studies and cited studies will also be performed. In case of missing data, authors will be contacted by e-mail or academic social networking sites whenever possible. To be included in the review, studies must be double-blind randomized controlled trials evaluating T diuretics alone or in combination with PS diuretics in patients with primary hypertension. The primary outcome measure will be office BP. Ambulatory BP monitoring (ABPM), non-melanoma skin cancer, major adverse cardiovascular events, laboratory parameters, and the number of withdrawals will be included as secondary outcomes. The results will be quantitatively summarized using differences between the mean change from baseline or differences between means for quantitative outcomes and relative risk for dichotomous outcomes. Results will be presented as mean or relative risk with credible intervals through a league table. The treatments will also be ranked using the surface under the cumulative ranking curve method. The risk of bias will be assessed through the RoB 1.0 tool. Discussion To the best of our knowledge, this review will be the first to synthesize currently available evidence on the antihypertensive efficacy of different T diuretics alone or in combination with PS diuretics in adults with hypertension. The goals of hypertension treatment are to control high BP and to reduce associated cardiovascular morbidity and mortality, using the most appropriate therapy. Thiazides are widely used for pharmacological treatment due to their demonstrated effectiveness in reducing BP, favorable safety profile, and low cost. The results of this study will provide evidence regarding the best therapeutic strategies with T and PS diuretics, evidencing interventions with better antihypertensive efficacy and safety profile. Trial registration This systematic review and network meta-analysis was prospectively registered at the PROSPERO database (CRD42018118492)

    Adubação nitrogenada e pulverização foliar de Azospirillum brasilense em trigo: efeitos na nutrição mineral e produtividade

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    The use of Azospirillum brasilense has the potential to improve plant nitrogen (N) use efficiency, while a better understanding of alternative management practices with inoculation is necessary. The aim was to examine the effects of the leaf application of A. brasilense in association with nitrogen fertilization on the wheat crop. The experiment was conducted in Lidianópolis, Paraná, Brazil, in a completely randomized block design with four replications. The treatments included four doses of A. brasilense for leaf application (0, 200, 400, and 600 ml ha-1) and four doses of N (0, 40, 80, and 120 kg N ha-1). The nutritional content, yield components, quality, and yield of the wheat crop were evaluated. There was no interaction among the factors, nor did the treatments have an isolated effect on spike length, the number of spikelets per spike, spikes per m2, thousand grain weight, and test weight. However, doses of A. brasilense increased calcium and magnesium absorption at 283 and 380 ml ha-1, respectively. Similarly, nitrogen application increased the content of calcium, magnesium, and copper in the leaf at 61, 47, and 49 kg N ha-1, respectively. Nitrogen also increased the number of grains per spike and yield at 56 and 54 kg N ha-1, respectively. Yield correlated with the number of grains per spike and the manganese and copper content in the leaf. The results demonstrate that the inoculation of leaves with A. brasilense favored a higher absorption of divalent cationic macronutrients and that N was fundamental to increasing the yield, with the best responses observed between 47 and 61 kg ha-1.O uso de Azospirillum brasilense apresenta potencial em melhorar a eficiência de uso do nitrogênio (N), sendo necessário melhor compreensão de formas alternativas de inoculação, visto que o tratamento químico de sementes pode comprometer a eficiência das bactérias. O objetivo foi avaliar os efeitos do A. brasilense aplicado via foliar associado a adubação nitrogenada na cultura do trigo. O experimento foi implantado em Lidianópolis, no estado do Paraná, Brasil, em blocos completos com tratamentos ao acaso e quatro repetições, sendo os tratamentos: quatro doses de A. brasilense via foliar (0, 200, 400 e 600 ml ha-1) e quatro doses de N (0, 40, 80 e 120 kg N ha-1). Foram avaliados os teores nutricionais, componentes de rendimento, qualidade e produtividade. Não houve interação entre os fatores, tampouco efeito isolado dos tratamentos para comprimento da espiga, número de espiguetas por espiga, espigas por m², massa de mil grãos e peso de hectolitro. Todavia as doses de A. brasilense, aumentaram a absorção de Ca e Mg até a dose de 283 e 380 ml ha-1, respectivamente. De modo similar, o N aplicado aumentou os teores foliares de cálcio, magnésio, além de cobre até a dose de 61, 47 e 49 kg ha-1 de N, respectivamente. O N também incrementou o número de grãos por espiga e a produtividade até a dose 56 e 54 kg N ha-1, respectivamente, porém a eficiência de uso de N diminuiu com o aumento da dose. A produtividade se correlacionou com número de grãos por espiga e teores foliares de manganês e cobre. Os resultados demonstram que a inoculação com A. brasilense foliar foi favorável a maior absorção de macronutrientes catiônicos divalentes, e o N fundamental para aumento da produtividade, sendo as melhores respostas obtidas entre as doses de 47 a 61 kg ha-1

    Effects of Transcranial Direct Current Stimulation on Psychophysiological Responses to Maximal Incremental Exercise Test in Recreational Endurance Runners

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    Previous studies have suggested that transcranial direct current stimulation (tDCS) might improve exercise performance and alter psychophysiological responses to exercise. However, it is presently unknown whether this simple technique has similar (or greater) effects on running performance. The purpose of this study was, therefore, to test the hypothesis that, compared with sham and cathodal tDCS, anodal tDCS applied over the M1 region would attenuate perception of effort, improve affective valence, and enhance exercise tolerance, regardless of changes in physiological responses, during maximal incremental exercise. In a double-blind, randomized, counterbalanced design, 13 healthy recreational endurance runners, aged 20–42 years, volunteered to participate in this study. On three separate occasions, the subjects performed an incremental ramp exercise test from rest to volitional exhaustion on a motor-driven treadmill following 20-min of brain stimulation with either placebo tDCS (sham) or real tDCS (cathodal and anodal). Breath-by-breath pulmonary gas exchange and ventilation and indices of muscle hemodynamics and oxygenation were collected continuously during the ramp exercise test. Ratings of perceived exertion (RPE) and affective valence in response to the ramp exercise test were also measured. Compared with sham, neither anodal tDCS nor cathodal tDCS altered the physiological responses to exercise (P > 0.05). Similarly, RPE and affective responses during the incremental ramp exercise test did not differ between the three experimental conditions at any time (P > 0.05). The exercise tolerance was also not significantly different following brain stimulation with either sham (533 ± 46 s) or real tDCS (anodal tDCS: 530 ± 44 s, and cathodal tDCS: 537 ± 40 s; P > 0.05). These results demonstrate that acute tDCS applied over the M1 region did not alter physiological responses, perceived exertion, affective valence, or exercise performance in recreational endurance runners

    Hydronephrosis in a Dog Related to Ovariosalpingohysterectomy

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    Background: Hydronephrosis is the dilation of the pelvis and renal calyxes due to post-renal obstruction. The obstruction is often associated with extraluminal masses, blood clots and ureter ligation in castration procedures. Ureter ligation is reported as a malpractice. The renal function is reestablished if ligation is rapidly undone, but not for obstructions longer than four weeks. Often, clinical signs are results from months to years after the castration, when nephrectomy is the best therapeutic option. This paper aims to report a case of asymptomatic unilateral hydronephrosis in a 10-year-old dog caused by chronic ureter occlusion with Nylon 3.0 suture during an elective procedure.Case: A 10-year-old female pinscher dog, spayed 3 years ago was admitted at the Surgery Department of the Veterinary Hospital of the Federal University of Jataí (HV-UFJ). The animal was taken for periodontal treatment. In the physical and laboratory examination (complete blood count, hepatic and renal biochemical tests) no significant and noteworthy alterations were found. Ultrasonographic examination showed no changes in the topography and echotexture of the left kidney, however the right kidney was not visualized, with an anechoic structure suggestive of advanced and severe hydronephrosis. Therefore, exploratory laparotomy was proposed to identify the observed structure, with the periodontal treatment considered for a later time. So, a retroumbilical incision was made, followed by linea alba and the removal of simple isolated suture remaining from previous surgical procedure. In the cavity, the viscera were isolated and the left kidney was identified, observing preserved anatomy. On the other hand, the right kidney had altered topography and morphology, being exposed after release of adhesions in adjacent structures. The right renal artery and vein were dissected and a double ligature was made. Then, the right ureter was dissected, observing marked dilatation in the proximal portion and the presence of local ligation with Nylon 3.0. Right ureterectomy and right nephrectomy were performed. After nephrectomy, the capsule was ruptured, observing dark fluid in it and absence of tissue compatible with renal parenchyma. The material was preserved in 10% formaldehyde and sent for histopathological examination. Histopathology revealed risk of rupture of the renal capsule due to the advance of renal degeneration and complete absence of parenchyma. However, contrary to the severity of the histopathological, surgical and ultrasonographic findings, the patient did not present clinical signs at the time of diagnosis.Discussion: In the intraoperative evaluation, the cause of the hydronephrosis was verified to be in fact the ligation of the ureter, which may have been accidental or due to the malpractice of the veterinarian surgeon. Other possible causes such as adhesions and granulomas were ruled out because the Nylon 3.0 suture was found in the proximal portion of the right ureter. It is believed that the patient may have presented clinical signs of hydronephrosis that may have been confused by the tutors as postoperative complications, changes that if identified and performed in time, could have avoided the occurrence or worsening of hydronephrosis and subsequent nephrectomy. Clinically, the bitch did not show clinical signs presented in the literature as consistent with hydronephrosis such as polyuria, polydipsia, abdominalgia, external fistula and anorexia. Therefore, it is believed that this case is one of the first reports of the occurrence of severe hydronephrosis without typical clinical manifestations of hydronephrosis. This fact raises a warning about the thorough monitoring in the postoperative period by owners and veterinarians, in addition to highlighting concerns regarding the occurrence of medical malpractice versus surgical accidents. Keywords: castration, malpractice, nephrectomy, nylon

    The Adverse Events in Lumbar Dynamic Stabilization: a Prospective Case Series

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    BACKGROUND: We aimed to evaluate the complication rate in lumbar dynamic stabilization surgery for back pain in situations where conventional rigid implants could have been employed, with a follow-up of at least five years. METHODS AND FINDINGS: All patients who underwent semi-rigid lumbar spine fixation with the dynamic system consecutively between 2002 and 2007 in our departmentwere included. Minimum follow up period was 5. Adverse events and reoperations were registered for analysis. In the study period, 144 patients were treated with the dynamic system and studied. Three screws were badly positioned. There were two (1,39%) infections, with surgical cleaning necessary in one case. The late complications included a radiolucency signal in 22 screws (2,86%) and four broken screws (0,52%) out of 770 screws.Nineteen patients (20,13%) needed reoperation due to pain or screw associated problems. Three (2,08%) of these cases received additional treatment due to segmental kyphosis, five (3,47%) due to flat back, five (3,47%) due to adjacent level stenosis, 4 (2,7%) due to lumbar pain complaints, and two (1,39%) due to a broken screw. CONCLUSIONS: The lumbar dynamic stabilization system is an option for the treatment of degenerative spinal diseases. However it is not free of adverse events and had rates of implant failure, complications, and reoperations similar to those described on literature with rigid systems
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