981 resultados para K-Fold Accuracy
Resumo:
Changes in composition during the maturation of Western Schley pecans [Carya illinoinensis (Wangenh.) K. Koch] grown in Australia were investigated. Pecans of different maturity levels were collected at monthly intervals between March and June in. 1999 and 2000 and analyzed for the concentrations of moisture, total lipid, sucrose, raffinose, protein, and the minerals aluminum, boron, calcium, copper, iron, potassium, magnesium, manganese, sodium, phosphorus, sulfur, and zinc. Moisture, total lipid, and calcium contents changed significantly (p < 0.05) with harvest time and maturity, whereas the other components did not. Western Schley pecans grown in Australia should be harvested after the shuck has opened and it is either green or brown in color to maximize total lipid content and quality. This occurred after May 11 in 1999 and after May 17 in 2000.
Resumo:
Regional commodity forecasts are being used increasingly in agricultural industries to enhance their risk management and decision-making processes. These commodity forecasts are probabilistic in nature and are often integrated with a seasonal climate forecast system. The climate forecast system is based on a subset of analogue years drawn from the full climatological distribution. In this study we sought to measure forecast quality for such an integrated system. We investigated the quality of a commodity (i.e. wheat and sugar) forecast based on a subset of analogue years in relation to a standard reference forecast based on the full climatological set. We derived three key dimensions of forecast quality for such probabilistic forecasts: reliability, distribution shift, and change in dispersion. A measure of reliability was required to ensure no bias in the forecast distribution. This was assessed via the slope of the reliability plot, which was derived from examination of probability levels of forecasts and associated frequencies of realizations. The other two dimensions related to changes in features of the forecast distribution relative to the reference distribution. The relationship of 13 published accuracy/skill measures to these dimensions of forecast quality was assessed using principal component analysis in case studies of commodity forecasting using seasonal climate forecasting for the wheat and sugar industries in Australia. There were two orthogonal dimensions of forecast quality: one associated with distribution shift relative to the reference distribution and the other associated with relative distribution dispersion. Although the conventional quality measures aligned with these dimensions, none measured both adequately. We conclude that a multi-dimensional approach to assessment of forecast quality is required and that simple measures of reliability, distribution shift, and change in dispersion provide a means for such assessment. The analysis presented was also relevant to measuring quality of probabilistic seasonal climate forecasting systems. The importance of retaining a focus on the probabilistic nature of the forecast and avoiding simplifying, but erroneous, distortions was discussed in relation to applying this new forecast quality assessment paradigm to seasonal climate forecasts. Copyright (K) 2003 Royal Meteorological Society.
Resumo:
Poly(2-hydroxyethyl methacrylate) and copolymers of 2-hydroxyethyl methacrylate (HEMA) and 1-vinyl-2-pyrrolidone (VP) in the form of cylindrical samples (approximate to8mm x 20mm) have been prepared and the sorption of water into these cylinders has been studied by the mass-uptake methods and by magnetic-resonance imaging. The equilibrium water contents for the cylinders were found to vary systematically with the copolymer composition. Diffusion of water into the cylinders was found to follow Fickian behaviour for cylinders with high HEMA contents, with the diffusion coefficients obtained from mass-uptake studies dependent on the copolymer composition, varying from 1.7 x 10(-11) m(2) s(-1) for poly(HEMA) to 2.0 x 10(-11) m(2) s(-1) for poly(HEMA-co-VP) with a composition of 1:1. However, NMR-imaging studies showed that, while the profiles of the water diffusion fronts for cylinders with high HEMA contents were Fickian, that for the 1:1 copolymer was not and indicated that the mechanism was Case III. The polymers which were rich in VP were characterized by a water-sorption process which follows Case-III behaviour. (C) 2003 Society of Chemical Industry.
Resumo:
The radiation chemical yields G(S) and G(X) for H-linking and Y-linking models for Ultem have been calculated from molecular weight analysis by gel permeation chromatography. These G-values have been compared with the G-values obtained from analysis of soluble fractions above the gel dose, Which have been reported in previous works. An analysis of the molecular weight data in terms of H-linking and Y-linking mechanisms yielded values of G(S-H) = 1.0 x 10(-3) and G(H) = 6.0 x 10(-3) and G(S-Y) = 1.3 x 10(-2) and G(Y) = 1.8 x 10(-2). The corresponding values obtained from the solubility data were G(SH) = 0.53 x 10(-2), G(H) = 1.39 x 10(-2), G(S-Y) = 4.2 x 10(-2) and G(Y) - 4.6 x 10(-2). The origin of the disagreement between the molecular weight and solubility values is not clear, but it could arise as a result of observed microgel formation below the reported gel dose of 0.13 MGy. Whether the crosslink mechanism proceeds by an H-linking or Y-linking process is also unclear and will require direct observation of the crosslinking structures.
Resumo:
Myocardial infarction leads to compensatory ventricular remodeling. Disturbances in myocardial contractility depend on the active transport of Ca2+ and Na+, which are regulated by Na+-K+ ATPase. Inappropriate regulation of Na+-K+ ATPase activity leads to excessive loss of K+ and gain of Na+ by the cell. We determined the participation of Na+-K+ ATPase in ventricular performance early and late after myocardial infarction. Wistar rats (8-10 per group) underwent left coronary artery ligation (infarcted, Inf) or sham-operation (Sham). Ventricular performance was measured at 3 and 30 days after surgery using the Langendorff technique. Left ventricular systolic pressure was obtained under different ventricular diastolic pressures and increased extracellular Ca2+ concentrations (Ca2+e) and after low and high ouabain concentrations. The baseline coronary perfusion pressure increased 3 days after myocardial infarction and normalized by 30 days (Sham 3 = 88 ± 6; Inf 3 = 130 ± 9; Inf 30 = 92 ± 7 mmHg; P < 0.05). The inotropic response to Ca2+e and ouabain was reduced at 3 and 30 days after myocardial infarction (Ca2+ = 1.25 mM; Sham 3 = 70 ± 3; Inf 3 = 45 ± 2; Inf 30 = 29 ± 3 mmHg; P < 0.05), while the Frank-Starling mechanism was preserved. At 3 and 30 days after myocardial infarction, ventricular Na+-K+ ATPase activity and contractility were reduced. This Na+-K+ ATPase hypoactivity may modify the Na+, K+ and Ca2+ transport across the sarcolemma resulting in ventricular dysfunction.
Resumo:
Introdução: Os ensaios de liberação do interferon- γ (ELIG) surgiram como uma alternativa para o diagnóstico de infecção latente pelo Mycobacterium tuberculosis (ILTB). Neste estudo, nós comparamos o desempenho de um dos ELIG, teste Quantiferon TB Gold in tube – QFT, com a prova tuberculínica (PT) em dois pontos de corte (≥ 5 mm e ≥ 10 mm), em profissionais de saúde da atenção básica à saúde (ABS). Métodos: Estudo transversal realizado em profissionais de saúde da ABS de quatro capitais nacionais com alta incidência de TB. O resultado do teste QFT foi comparado com o resultado da PT nos pontos de corte ≥ 5mm e ≥ 10 mm. Resultados: Foram incluídos 632 profissionais de saúde. Ao considerar o ponto de corte ≥ 10 mm para a PT, a concordância entre QFT e a PT foi de 69% (k = 0,31) e para o ponto de corte ≥ 5 mm, a concordância entre os testes foi de 57% (k = 0,22). Devido a baixa concordância entre a PT e o QFT, nós avaliamos os possíveis fatores associados com a discordância entre eles. Ao comparar o grupo PT- / QFT- com o grupo PT+ / QFT-, no ponto de corte ≥ 5 mm, a idade entre 41-45 [OR = 2,70, IC 95%: 1,32-5,51] e 46-64 [OR = 2,04, IC 95%: 1,05-3,93], presença de cicatriz vacinal do BCG [OR = 2,72, IC 95%: 1,40-5,25] e trabalhar apenas na ABS [OR = 2,30, IC 95 %: 1,09-4,86] apresentaram associação estatística significativa. Para o ponto de corte ≥ 10 mm, a presença de cicatriz vacinal do BCG [OR = 2,26, IC 95%: 1,03-4,91], ter tido contato domiciliar com paciente portador de tuberculose ativa [OR = 1,72, IC 95%: 1,01-2,92] e ter feito a PT anteriormente [OR = 1,66, IC 95%: 1,05-2,62] revelaram associação estatística significativa. Curiosamente, a discordância observada no grupo PT- / QFT + não apresentou associação estatistica com nenhuma das variáveis consideradas, independentemente do ponto de corte da PT. Conclusões: Apesar de termos identificado que a vacina BCG contribuiu para a discordância entre os testes, as recomendações brasileiras para o início do tratamento da ILTB não devem ser alteradas devido as limitações do QFT.
Resumo:
As características das leguminosas e gramíneas usadas como plantas de cobertura são bastante conhecidas, mas a velocidade com que os nutrientes associados à biomassa vegetal tornam-se disponíveis às culturas é ainda pouco estudada. O objetivo deste trabalho foi determinar o acúmulo e a taxa de liberação de nutrientes de crotalária e milheto solteiros ou consorciados. O delineamento experimental adotado foi blocos ao acaso, com quatro repetições. Os tratamentos foram crotalária, milheto, crotalária + milheto e vegetação espontânea. O acúmulo de P e Mg foi influenciado pela produção de massa, com valores elevados na crotalária, enquanto o acúmulo de Ca resultou tanto do maior teor quanto da maior produção de massa nos tratamentos com a leguminosa. A liberação de nutrientes dos resíduos apresentou dinâmica semelhante, com duas fases distintas: a primeira com taxas mais elevadas nos primeiros 15 dias e a segunda mais lenta a partir dessa fase. As taxas de liberação de K, Ca e Mg foram semelhantes, independentemente dos tratamentos. Os resíduos da crotalária apresentaram maior liberação de P do que as da vegetação espontânea, com meia vida de 11 dias e a vegetação espontânea de 17 dias. O Ca foi liberado mais lentamente do que os demais nutrientes, e o Mg mais rapidamente. As plantas espontâneas e o milheto apresentam importante potencial na reciclagem de K, e a crotalária se destacou na reciclagem de Ca e Mg.
Resumo:
The chlorophyll meter (SPAD-502) is widely used to estimate chlorophyll content, but non-uniform chloroplast distribution can affect its accuracy. This study aimed to assess the effect of photon fluence (F, irradiance x time of illumination) in leaves with different chlorophyll content and determine the effect of chlorophyll a/b on SPAD values of four tropical tree species (Croton draconoides Müll. Arg., Hevea guianensis Aubl., Hymenaea courbaril L. and Matisia cordata H.B.K.). There were also determined calibration equations for the chlorophyll meter and assessed the effect of F on SPAD values between 07:00 h and 17:00 h. Calibration equations were obtained after determining leaf chlorophyll content in the laboratory. Increases in F with time caused a reduction in SPAD values in species with a high chlorophyll content, with reductions of 20% in M. cordata and 10% in H. guianensis. Leaves of C. draconoides and H. courbaril had lower chlorophyll content and showed no changes in SPAD values with increase in F. The chlorophyll a/b ratio increased with SPAD values and the SPAD/chlorophyll relationship was best described by an exponential equation. It seems that F may affect SPAD values in leaves with high chlorophyll content, probably due to non-uniform chloroplast distribution at high irradiance. This indicates that SPAD values tend to be more accurate if recorded early in morning when irradiance is low.
Resumo:
The objective of this work was to evaluate the quality of fruits and the nutritional status of cucumber CV. Aodai cultivated in nutrient solutions with different N:K ratios. The hydroponic cultivation was initially performed, during the vegetative growth, in nutrient solution with 1:2.0 mmol L-1 N:K, and, later, during fruit setting, in four different nutrient solutions with N:K (w/w) at the ratios 1:1.4, 1:1.7, 1:2.0 and 1:2.5. An additional treatment with a nutrient solution containing the ratio 1:2.2 (w/w) N:K during the vegetative growth and N:K 1:1.4 (w/w) during fruit setting, both with 10% ammonium (NH4+) was included. The treatments were arranged in a randomized design with six replicates. Irrigation was carried out with deionized water until seed germination, and then with nutrient solution until 30 days after germination, when plants were transplanted. Plants in the hydroponic growing beds were irrigated with the solutions for vegetative growth, and, after 21 days, the solutions were replaced by solutions for fruit setting. At 45 and 60 days after transplanting, the fresh weight, length, diameter, volume and firmness of the fruit were evaluated, and, at 45 days after transplanting, the macronutrient concentrations in the leaves were determined. The use of different N:K ratios during fruit setting influenced the cucumber production. The ratio of 1.0:1.7 N: K (w/w), with 10% of N in the form of ammonia, is recommended for the whole cycle.
Resumo:
An adequate supply of nutrients is essential for obtaining high yields of coffee. The objective of this study was to evaluate the effect of N, K and the N:K ratio on vegetative and reproductive growth of coffee. For this purpose, coffee plants were grown in nutrient solution containing K in the concentrations of 1.08; 2.15; 3.23 and 5.38 mmol L-1 combined with a dose of 6 mmol L-1 N, resulting in the N:K ratios (w/w): 1:0.5; 1:1; 1:1.5 and 1:2.5. The control treatment consisted of the doses 3 and 1.61 mmol L-1 of N and K respectively, resulting in the N:K ratio (w/w) 1.0:1.5. The following variables were evaluated: height, stem diameter, number of nodes of the eighth plagiotrofic branch (index branch), pairs of plagiotrofic branches and number of nodes in the orthotropic branch every three weeks from the beginning of the experiment. Additionally, it was evaluated the chemical composition of processed beans and leaves between the flowering and the rapid expansion stage of the cherry beans, production of cherry beans per plant and classification of beans according to the size. N influenced mainly the characteristics of vegetative growth and K influenced mainly the reproductive growth evaluated by the production. The lowest production resulted in the highest percentages of beans retained on sieves with holes larger than 16/64", while the highest production promoted an increase in the percentage of beans retained on sieves with holes smaller than 16/64".
Resumo:
In this paper, we present a method for estimating local thickness distribution in nite element models, applied to injection molded and cast engineering parts. This method features considerable improved performance compared to two previously proposed approaches, and has been validated against thickness measured by di erent human operators. We also demonstrate that the use of this method for assigning a distribution of local thickness in FEM crash simulations results in a much more accurate prediction of the real part performance, thus increasing the bene ts of computer simulations in engineering design by enabling zero-prototyping and thus reducing product development costs. The simulation results have been compared to experimental tests, evidencing the advantage of the proposed method. Thus, the proposed approach to consider local thickness distribution in FEM crash simulations has high potential on the product development process of complex and highly demanding injection molded and casted parts and is currently being used by Ford Motor Company.
Resumo:
RESUMO O gênero Cordiera (Rubiaceae) possui aproximadamente 25 espécies e ampla distribuição no Brasil. Seus representantes são árvores ou arbustos dioicos, com flores funcionalmente unissexuadas. Este estudo foi realizado em dois fragmentos de Floresta Estacional Semidecidual, no município de Tangará da Serra, MT. Foram investigadas a fenologia reprodutiva, a razão sexual, a morfologia e a biologia floral, o sistema e o sucesso reprodutivo. Cordiera macrophylla floresceu de julho a setembro, durante a estação seca, com pico sincrônico entre flores pistiladas e estaminadas. Flores estaminadas florescem antecipadamente e por um período mais prolongado que as pistiladas. A antese das flores pistiladas apresentou maior longevidade. A razão sexual foi de 1:1. Flores estaminadas são dispostas em inflorescências umbeliformes e as pistiladas são unifloras, ambas semelhantes morfologicamente. Os frutos são bagas verrucosas, polispérmicas. A taxa de formação de frutos por polinização natural foi de 95%, evidenciando a dependência dos polinizadores para a manutenção da espécie. O sucesso reprodutivo também foi alto, confirmando que a associação entre morfologia e biologia floral favoreceu a espécie nas áreas estudadas.
Resumo:
ABSTRACT Soils of tropical regions are more weathered and in need of conservation managements to maintain and improve the quality of its components. The objective of this study was to evaluate the availability of K, the organic matter content and the stock of total carbon of an Argisol after vinasse application and manual and mechanized harvesting of burnt and raw sugarcane, in western São Paulo.The data collection was done in the 2012/2013 harvest, in a bioenergy company in Presidente Prudente/SP. The research was arranged out following a split-plot scheme in a 5x5 factorial design, characterized by four management systems: without vinasse application and harvest without burning; with vinasse application and harvest without burning; with vinasse application and harvest after burning; without vinasse application and harvest after burning; plus native forest, and five soil sampling depths (0-10 10-20, 20-30, 30-40, 40-50 cm), with four replications. In each treatment, the K content in the soil and accumulated in the remaining dry biomass in the area, the levels of organic matter, organic carbon and soil carbon stock were determined. The mean values were compared by Tukey test. The vinasse application associated with the harvest without burning increased the K content in soil layers up to 40 cm deep. The managements without vinasse application and manual harvest after burning, and without vinasse application with mechanical harvesting without burning did not increase the levels of organic matter, organic carbon and stock of total soil organic carbon, while the vinasse application and harvest after burning and without burning increased the levels of these attributes in the depth of 0-10 cm.
Resumo:
Background: Several studies link the seamless fit of implant-supported prosthesis with the accuracy of the dental impression technique obtained during acquisition. In addition, factors such as implant angulation and coping shape contribute to implant misfit. Purpose: The aim of this study was to identify the most accurate impression technique and factors affecting the impression accuracy. Material and Methods: A systematic review of peer-reviewed literature was conducted analyzing articles published between 2009 and 2013. The following search terms were used: implant impression, impression accuracy, and implant misfit.A total of 417 articles were identified; 32 were selected for review. Results: All 32 selected studies refer to in vitro studies. Fourteen articles compare open and closed impression technique, 8 advocate the open technique, and 6 report similar results. Other 14 articles evaluate splinted and non-splinted techniques; all advocating the splinted technique. Polyether material usage was reported in nine; six studies tested vinyl polysiloxane and one study used irreversible hydrocolloid. Eight studies evaluated different copings designs. Intraoral optical devices were compared in four studies. Conclusions: The most accurate results were achieved with two configurations: (1) the optical intraoral system with powder and (2) the open technique with splinted squared transfer copings, using polyether as impression material.
Resumo:
RESUMO Em cultivos hidropônicos de hortaliças folhosas destacam-se, dentre os fatores que influenciam a produção e qualidade do produto, as exigências nutricionais da cultura. Objetivou-se, com este trabalho, avaliar o efeito de concentrações de N, P e K sobre a produção de matéria seca e a nutrição mineral em cebolinha 'Todo ano' (Allium fistulosum L.), cultivada em condições hidropônicas. Foram conduzidos três experimentos, um com cada nutriente em três níveis: deficiente, adequado e excessivo. Empregou-se o delineamento inteiramente casualizado, em esquema de parcelas subdivididas no tempo, com quatro repetições e dez plantas por parcela. Aos 15, 30, 45 e 60 dias após o transplante (DAT), foi avaliada a produção de matéria seca da parte aérea e de raízes. Aos 45 e 60 DAT, avaliaram-se os teores e os acúmulos totais de N, P e K e os teores de Ca e Mg da parte aérea da planta. Em cultivos hidropônicos, as deficiências de N e P são mais limitantes que a de K ao crescimento da cebolinha cultivar 'Todo Ano', sendo que níveis baixos de P afetam principalmente o crescimento do sistema radicular da planta. A deficiência de N afeta a absorção de P, K, Ca e Mg. O excesso de N em cebolinha manifesta-se pelo crescimento excessivo da parte aérea e pelo aumento da flacidez das folhas. Os excessos de P e de K na solução nutritiva não provocam sintomas visuais de toxicidade de P ou de K, mas níveis excessivos de K diminuem os teores de Ca e de Mg da parte aérea da planta.