9,826 research outputs found

    Movimentação de inseticidas de tratamento de sementes no solo sob efeito da irrigação.

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    Este trabalho foi desenvolvido no Centro Nacional de Pesquisa de Milho e Sorgo (CNPMS), EMBRAPA, Sete Lagoas, MG, e teve como objetivo avaliar o movimento de inseticidas de tratamento de sementes de milho no perfil do solo em areas irrigadas. Foram utilizadas tres laminas de irrigacao: deficiente (50% da adequada), adequada e excessiva (100% superior a adequada), e dois inseticidas de tratamento de semente de milho: Semevin 350 RA (Thiodicarb) e Furadan 350 TS (Carbofuran), nas doses recomendadas pelos fabricantes. O monitoramento da lixiviacao desses inseticidas no solo foi feito em camadas de 5 cm e em quatro intervalos de 10 dias, a partir semeadura. A analise de residuo das amostras de solo foi feita utilizando-se cromatografia liquida de alta performance (HPLC). Nas condicoes em que foi realizado o experimento obtiveram-se as seguintes conclusoes: o Thiodicarb apresentou-se o mais instavel (com relacao a sua atividade) no solo com baixo risco de contaminacao do lencol freatico; o Carbofuran apresentou-se com um potencial maior de lixiviacao no perfil do solo devido, possivelmente, a sua resistencia a degradacao e, com baixo risco de contaminacao do lencol freatico para as condicoes apresentadas. Para todos os tratamentos, houve maior retencao do principio ativo dos inseticidas nas camadas mais superficiais (0 a 15 cm) do solo

    Esmolol Endovenoso em Regime Bail Out Para Controlo de Frequência Cardíaca na Tomografia Computorizada Cardíaca

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    OBJECTIVE: To evaluate the efficacy and safety of a heart rate (HR) reduction protocol using intravenous esmolol as bailout for failed oral metoprolol regimens in patients undergoing coronary computed tomography angiography (CCTA) with 64-slice multidetector computed tomography (64-MDCT). METHODS: Patients who underwent cardiac 64-MDCT in a single institution between 2011 and 2014 were analyzed. Those with HR above 60 beats per minute (bpm) on presentation received oral metoprolol (50-200 mg) at least one hour before CCTA. Intravenous esmolol 1-2 mg/kg was administered as a bolus whenever HR remained over 65 bpm just before imaging. The primary efficacy endpoint was HR <65 bpm during CCTA. The primary safety endpoint was symptomatic hypotension or bradycardia up to hospital discharge. RESULTS: During the study period CCTA was performed in 947 cases. In 86% of these, oral metoprolol was the only medication required to successfully reduce HR <60 bpm. Esmolol was used in the remaining 130 patients (14%). For esmolol-treated patients mean baseline and acquisition HR were 74±14 bpm and 63±9 bpm, respectively (p<0.001). The target HR of <65 bpm was achieved in 82 of the 130 esmolol-treated patients (63%). Considering the whole population, esmolol use led to a significant increase in the primary efficacy endpoint from 86% to 95% (p<0.001). Esmolol also resulted in a statistically, but not clinically, significant reduction in systolic blood pressure (144±22 to 115±17 mmHg; p<0.001). The combined primary safety endpoint was only observed in two (1.5%) patients. CONCLUSION: Despite optimal use of oral beta-blockers, 14% of patients needed intravenous esmolol for HR control. The pre-medication combination of oral metoprolol and on-demand administration of intravenous esmolol was safe and effective and enabled 95% of patients to be imaged with HR below 65 bpm.info:eu-repo/semantics/publishedVersio

    Método simplificado de determinação de resíduos de carbofuran e thiodicarb em solo com a utilização de cromatografia líquida.

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    Análises realizadas por cromatografia líquida de alta eficiência apresentaram algumas dificuldades, principalmente no que diz respeito ao elevado custo atribuído à demanda por uma grande quantidade de materiais, solventes e rotinas analíticas extensas. Uma série de tentativas foram feitas no laboratório de Agroquímica da EMBRAPA-Milho e Sorgo em Sete Lagoas, MG, buscando uma forma simplificada de extração e análise de pesticidas em solo. Este trabalho teve como objetivo desenvolver uma metodologia de extração e análise de carbofuran e thiodicarb em solo que reduzisse o custo analítico, com menor tempo de processamento. para isso, foram aplicados carbofuran e thiodicarb em latossolo Vermelho-Escuro, nas concentrações de 0,1; 0,5; 1,0; 5,0 e 10,0 mg dm-3. Os inseticidas foram quantificados pela técnica do padrão externo e a taxa de recuperação foi de 95 a 110%, com ambos os produtos. o uso da metodologia simplificada mostrou-se perfeitamente satisfatório, não comprometendo a qualidade da análise

    Model selection for spectro-polarimetric inversions

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    Inferring magnetic and thermodynamic information from spectropolarimetric observations relies on the assumption of a parameterized model atmosphere whose parameters are tuned by comparison with observations. Often, the choice of the underlying atmospheric model is based on subjective reasons. In other cases, complex models are chosen based on objective reasons (for instance, the necessity to explain asymmetries in the Stokes profiles) but it is not clear what degree of complexity is needed. The lack of an objective way of comparing models has, sometimes, led to opposing views of the solar magnetism because the inferred physical scenarios are essentially different. We present the first quantitative model comparison based on the computation of the Bayesian evidence ratios for spectropolarimetric observations. Our results show that there is not a single model appropriate for all profiles simultaneously. Data with moderate signal-to-noise ratios favor models without gradients along the line-of-sight. If the observations shows clear circular and linear polarization signals above the noise level, models with gradients along the line are preferred. As a general rule, observations with large signal-to-noise ratios favor more complex models. We demonstrate that the evidence ratios correlate well with simple proxies. Therefore, we propose to calculate these proxies when carrying out standard least-squares inversions to allow for model comparison in the future.Comment: 16 pages, 2 figures, 8 tables, accepted for publication in Ap

    Granulomas caused by Mycobacterium sp. in farmed Turbot Scopthalmus maximus (Linnaeus, 1758)

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    Turbot, Scophthlalmus maximus, is a Pleuronectiformes fish that occurs in northeast Atlantic along the European coast and in the Mediterranean Sea and is produced in aquaculture since the last quarter of the twentieth century. During a survey conducted in a turbot fish farm nodular formations were occasionally observed in several organs, especially in the kidney and in the spleen. Microscopic observations showed that these nodules contained acid-fast bacilli. The molecular identification of the isolated bacteria conducted to the Mycobacterium genus. Although no abnormal mortalities were evident morbidity was observed. The normal development and welfare of infected fish decrease and the condition factor, the haematocrit and the haemoglobin concentration in blood decreases significantly with the increase of nodules abundance

    Os jovens pouco escolarizados no mercado de trabalho português

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    S0003-25732014000100004 (Nº de Acesso Web of Science)Este artigo analisa as mudanças estruturais do emprego juvenil entre os 15 e 24 anos de idade, com escolaridade básica obrigatória (ISCED 0-2), nos anos de 1988, 1998 e 2007, tendo por base dados não publicados dos Quadros de Pessoal do Ministério do Trabalho e da Solidariedade Social. A exploração das variáveis contrato, antiguidade, duração do tempo de trabalho e remuneração, permite configurar uma autonomização do mercado de trabalho da mão-de-obra juvenil face à generalidade do mercado de trabalho. Conclui-se argumentando que a escolaridade é um factor diferenciador da relação de emprego dos jovens menos escolarizados face aos mais escolarizados

    Non-local thermodynamic equilibrium inversions from a 3D MHD chromospheric model

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    The structure of the solar chromosphere is believed to be governed by magnetic fields, even in quiet-Sun regions that have a relatively weak photospheric field. During the past decade inversion methods have emerged as powerful tools for analyzing the chromosphere of active regions. The applicability of inversions to infer the stratification of the physical conditions in a dynamic 3D solar chromosphere has not yet been studied in detail. This study aims to establish the diagnostic capabilities of non-local thermodynamical equilibrium (NLTE) inversion techniques of Stokes profiles induced by the Zeeman effect in the Ca II 8542 line. We computed the Ca II atomic level populations in a snapshot from a 3D radiation-MHD simulation of the quiet solar atmosphere in non-LTE using the 3D radiative transfer code Multi3d. These populations were used to compute synthetic full-Stokes profiles in the Ca II 8542 line using 1.5D radiative transfer and the inversion code Nicole. The profiles were then spectrally degraded to account for finite filter width and Gaussian noise was added to account for finite photon flux. These profiles were inverted using Nicole and the results were compared with the original model atmosphere. Our NLTE inversions applied to quiet-Sun synthetic observations provide reasonably good estimates of the chromospheric magnetic field, line-of-sight velocities and somewhat less accurate, but still very useful, estimates of the temperature. Three dimensional scattering of photons cause cool pockets in the chromosphere to be invisible in the line profile and consequently they are also not recovered by the inversions. To successfully detect Stokes linear polarization in this quiet snapshot, a noise level below 10^{-3.5} is necessary.Comment: Accepted for publication in Astronomy & Astrophysic

    Asymptotically Improved Convergence of Optimized Perturbation Theory in the Bose-Einstein Condensation Problem

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    We investigate the convergence properties of optimized perturbation theory, or linear δ\delta expansion (LDE), within the context of finite temperature phase transitions. Our results prove the reliability of these methods, recently employed in the determination of the critical temperature T_c for a system of weakly interacting homogeneous dilute Bose gas. We carry out the explicit LDE optimized calculations and also the infrared analysis of the relevant quantities involved in the determination of TcT_c in the large-N limit, when the relevant effective static action describing the system is extended to O(N) symmetry. Then, using an efficient resummation method, we show how the LDE can exactly reproduce the known large-N result for TcT_c already at the first non-trivial order. Next, we consider the finite N=2 case where, using similar resummation techniques, we improve the analytical results for the nonperturbative terms involved in the expression for the critical temperature allowing comparison with recent Monte Carlo estimates of them. To illustrate the method we have considered a simple geometric series showing how the procedure as a whole works consistently in a general case.Comment: 38 pages, 3 eps figures, Revtex4. Final version in press Phys. Rev.
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