9,826 research outputs found
Movimentação de inseticidas de tratamento de sementes no solo sob efeito da irrigação.
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 CardÃaca na Tomografia Computorizada CardÃaca
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 resÃduos de carbofuran e thiodicarb em solo com a utilização de cromatografia lÃquida.
Análises realizadas por cromatografia lÃquida de alta eficiência apresentaram algumas dificuldades, principalmente no que diz respeito ao elevado custo atribuÃdo à demanda por uma grande quantidade de materiais, solventes e rotinas analÃticas extensas. Uma série de tentativas foram feitas no laboratório de AgroquÃmica 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 analÃtico, 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
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)
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
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
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
We investigate the convergence properties of optimized perturbation theory,
or linear 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 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 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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