77 resultados para persistency
Resumo:
An experiment on restricted suckling of crossbred dairy cows was conducted at the Livestock Research Centre, Tanga in north-east Tanzania. The objective of the experiment was to evaluate the comparative productivity of Bos taurus x Bos indicus cows of medium and high levels of Bos taurus inheritance, whose calves were either bucket-reared or suckled residual milk. Lactation milk yield, length and persistency were 1563 L, 289 days, and 1.0, respectively, for the bucket-reared and 1592 L, 289 days and 1.4, respectively, for the suckling group. Days to observed oestrus, first insemination and conception for cows whose calves were bucket-reared were 47, 74 and 115 days, respectively, and 57, 81 and 126 days, respectively, for the suckling cows. The calf weights were similar at 1 year of age. The productivity of the cows, measured as the annual milk offtake, was not significantly higher for those that suckled their calves than for those whose calves were bucket-reared.
Resumo:
The occurrence of strong and persistent mid-latitude anticyclonic ridges over the Eastern North Atlantic is a major contributor to the occurrence of severe winter droughts over Western Iberia. We analyze the development of strong and persistent ridge episodes within 40–50°N; 40°W–5°E, which are defined as 300 hPa geopotential height anomalies above 50 gpm that persist for at least 10 consecutive days. Results suggest that the generation and maintenance of these episodes, with positive stratospheric geopotential anomalies over the North American continent and the adjacent North Pacific, are associated with an intensified polar jet. Such positive anomalies tend to detach from the main stratospheric anomaly and propagate eastwards and downwards as Rossby tropospheric waves. Furthermore, the Eastern North Atlantic ridge is generated and repeatedly reinforced until the stratospheric anomaly dissipates. Results also show evidence for waves breaking anticyclonically during the episodes, which is dynamically coherent with their persistency and quasi-stationarity.
Resumo:
The skill of a forecast can be assessed by comparing the relative proximity of both the forecast and a benchmark to the observations. Example benchmarks include climatology or a naïve forecast. Hydrological ensemble prediction systems (HEPS) are currently transforming the hydrological forecasting environment but in this new field there is little information to guide researchers and operational forecasters on how benchmarks can be best used to evaluate their probabilistic forecasts. In this study, it is identified that the forecast skill calculated can vary depending on the benchmark selected and that the selection of a benchmark for determining forecasting system skill is sensitive to a number of hydrological and system factors. A benchmark intercomparison experiment is then undertaken using the continuous ranked probability score (CRPS), a reference forecasting system and a suite of 23 different methods to derive benchmarks. The benchmarks are assessed within the operational set-up of the European Flood Awareness System (EFAS) to determine those that are ‘toughest to beat’ and so give the most robust discrimination of forecast skill, particularly for the spatial average fields that EFAS relies upon. Evaluating against an observed discharge proxy the benchmark that has most utility for EFAS and avoids the most naïve skill across different hydrological situations is found to be meteorological persistency. This benchmark uses the latest meteorological observations of precipitation and temperature to drive the hydrological model. Hydrological long term average benchmarks, which are currently used in EFAS, are very easily beaten by the forecasting system and the use of these produces much naïve skill. When decomposed into seasons, the advanced meteorological benchmarks, which make use of meteorological observations from the past 20 years at the same calendar date, have the most skill discrimination. They are also good at discriminating skill in low flows and for all catchment sizes. Simpler meteorological benchmarks are particularly useful for high flows. Recommendations for EFAS are to move to routine use of meteorological persistency, an advanced meteorological benchmark and a simple meteorological benchmark in order to provide a robust evaluation of forecast skill. This work provides the first comprehensive evidence on how benchmarks can be used in evaluation of skill in probabilistic hydrological forecasts and which benchmarks are most useful for skill discrimination and avoidance of naïve skill in a large scale HEPS. It is recommended that all HEPS use the evidence and methodology provided here to evaluate which benchmarks to employ; so forecasters can have trust in their skill evaluation and will have confidence that their forecasts are indeed better.
Resumo:
Este artigo investiga versões do modelo de passeio aleatório dos preços de ativos em diversos horizontes de tempo, para carteiras diversificadas de ações no mercado brasileiro. Evidências contrárias a tal modelo são observadas nos horizontes diário e semanal, caracterizados por persistência. As evidências são mais fracas em períodos mais recentes. Encontramos também sazonalidades diárias, incluindo o efeito segunda-feira, e mensais. Adicionalmente, um padrão de assimetria de autocorrelações cruzadas de primeira ordem entre os retornos de carteiras de firmas agrupadas segundo seu tamanho também é observado, indicando no caso de retornos diários e semanais que retornos de firmas grandes ajudam a prever retornos de firmas pequenas. Evidências de não linearidades nos retornos são observadas em diversos horizontes de tempo.
Resumo:
The Human Papillomavirus (HPV) infection is the major sexually transmitted disease all over the world. There are many factors associated to infection and the virus persistency in the organism. This study aims to evaluate the women's knowledge, attitudes and practice about the Papanicolaou test (Pap), as well as analyze the HPV and Chlamydia trachomatis infections prevalences in sexually active women from the city of São José do Mipibu/RN/Brazil. This research was divided in two steps (step I and step II), using different methodologies and samples each. The samples collected in each step, even socio-demographic or from uterus cervix, are from different patients e were analyzed separated. In step I was evaluated 267 rural and urban zone women s knowledge, attitudes and practices about the Pap by home interview. In the step II were included 605 women with age ranged from 15 to 71 years old, with mean of 33,5 years old and from each one were collected two cervical samples, one for Pap and other for molecular biology, beside the epidemiological interview to investigate the correlation between prevalence of HPV infection and risk factors. To molecular analyses, the samples were processed using a mammal rapid DNA extraction technique protocol. For C. trachomatis DNA detection were used the CP24/27 primers, and GP5+/GP6+ to HPV. PCR products were analyzed by electrophoresis on 8% polyacrylamide gels, followed by silver staining. The results of the step I showed that, in spite of only 46,1% of the interviewed women they have demonstrated to possess appropriate knowledge on the Pap test, the attitude and practice proportions were significantly larger, 63,3% and 64,4% respectively. The largest education degree presented association with adaptation of the knowledge, attitudes and practice, while neglect, lack of solicitation of the exam for the doctor and shame, came as main barriers for the accomplishment of the exam. In the stage II the HPV general prevalence was 28,9%, being 26,7% in the women with normal cytology or benign alterations, 26,7% in the ones that had atypical squamous cells of undetermined significance (ASC-US) and 80% in those with Low grade squamous intraepithelial lesion (LSIL). the HPV infection prevalence was larger in the patients with up to 30 years of age and in the unmarried women, and those that had more than one sexual partner presented larger infection risk. The results show that the sexual relationship with multiple partners increased the infection risk for HPV and consequently the possibility of the occurrence of lesions uterine cervix
Resumo:
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Resumo:
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Resumo:
Foram ajustadas 7239 curvas de lactação de vacas Caracu, controladas semanalmente entre os anos de 1978 a 1988, pertencentes à Fazenda Chiqueirão, Poços de Caldas, MG. As funções utilizadas foram a linear hiperbólica (FLH), a quadrática logarítmica (FQL), a gama incompleta (FGI) e a polinomial inversa (FPI). Os parâmetros foram estimados por meio de regressões não lineares, usando-se processos iterativos. A verificação da qualidade do ajuste baseou-se no coeficiente de determinação ajustado (R²A), no teste de Durbin-Watson (DW) e nas médias e desvios-padrão estimados para os parâmetros e funções dos parâmetros dos modelos. Para a curva média, os R²A foram superiores a 0,90 para todas as funções. Bons ajustes, baseados nos R²A>0,80 foram obtidos, respectivamente, por 25,2%, 39,1%, 31,1% e 28,4% das lactações ajustadas pelas funções FLH, FQL, FGI e FPI. de acordo com o teste de DW, bons ajustes foram proporcionados para 29,4% das lactações ajustadas pela FLH, 54,9% pela FQL, 34,9% pela FGI e 29,6% pela FPI. Para ambos os critérios, a FQL foi superior às demais funções, indicando grande variação nas formas das curvas de lactação geradas pelos ajustes individuais. Curvas atípicas foram estimadas pelas funções, com picos ocorrendo antes do parto e algumas vezes após o término da lactação. Todas as funções apresentaram problemas quando ajustaram dados individuais.
Resumo:
O experimento desenvolveu-se no Setor de Caprinocultura da FMVZ - UNESP - Campus de Botucatu, com o objetivo de estudar a influência da somatotropina bovina recombinante (rbST - nome comercial: Boostin 250 mg) na produção de leite, nos constituintes do leite, peso e escore de condição corporal de cabras durante o ciclo lactacional. Foram usadas 21 cabras da raça Parda Alpina, com idade entre 1 ½ e 4 anos, distribuídas aleatoriamente entre três tratamentos de sete animais cada: controle (T1 - sem rbST); completo, safra e entressafra (T2 - rbST após 45 dias de lactação); e apenas entressafra (T3 - rbST após 154 dias de lactação). Os animais dos três tratamentos receberam a mesma alimentação, que diferiu apenas na quantidade de concentrado, ajustada de acordo com a produção de leite dos animais. Não se observou aumento na produção de leite dos animais tratados, mas a persistência da lactação foi maior nestes animais. Não se observou diferença entre animais controles e tratados quanto aos constituintes do leite (densidade, gordura, EST, lactose e proteína). O peso e o índice de condição corporal também não apresentaram diferença significativa entre animais tratados e controle.
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
The objective of this study was to apply factor analysis to describe lactation curves in dairy buffaloes in order to estimate the phenotypic and genetic association between common latent factors and cumulative milk yield. A total of 31 257 monthly test-day milk yield records from buffaloes belonging to herds located in the state of São Paulo were used to estimate two common latent factors, which were then analysed in a multi-trait animal model for estimating genetic parameters. Estimates of (co)variance components for the two common latent factors and cumulated 270-d milk yield were obtained by Bayesian inference using a multiple trait animal model. Contemporary group, number of milkings per day (two levels) and age of buffalo cow at calving (linear and quadratic) as covariate were included in the model as fixed effects. The additive genetic, permanent environmental and residual effects were included as random effects. The first common latent factor (F1) was associated with persistency of lactation and the second common latent factor (F2) with the level of production in early lactation. Heritability estimates for Fl and F2 were 0.12 and 0.07, respectively. Genetic correlation estimates between El and F2 with cumulative milk yield were positive and moderate (0.63 and 0.52). Multivariate statistics employing factor analysis allowed the extraction of two variables (latent factors) that described the shape of the lactation curve. It is expected that the response to selection to increase lactation persistency is higher than the response obtained from selecting animals to increase lactation peak. Selection for higher total milk yield would result in a favourable correlated response to increase the level of production in early lactation and the lactation persistency.
Resumo:
O objetivo principal desta revisão foi reunir informações a respeito da ação de compostos orgânicos produzidos por plantas na disponibilidade de nutrientes nos solos, principalmente sobre os cátions Ca, Mg e K e sobre o ânion fosfato. O sistema de cultivo adotado ocasiona mudanças nas propriedades químicas e físicas do solo, especialmente na disponibilidade de nutrientes e condicionamento físico do solo. Tem-se observado o acúmulo de nutrientes nas camadas superficiais do solo no sistema de semeadura direta, pelo não-revolvimento do solo e pela deposição de resíduos de culturas na superfície. Os ácidos orgânicos provenientes de plantas podem interagir com a fase sólida e ocupar os sítios de adsorção de nutrientes, competindo diretamente com eles e aumentando sua disponibilidade no solo. A adição de resíduos vegetais pode promover, antes da humificação, a elevação do pH, por promover complexação de H e Al com compostos do resíduo vegetal, deixando Ca, Mg e K mais livres em solução, o que pode ocasionar aumento na saturação da CTC por estes cátions de reação básica. Também é normal observar o aumento na disponibilidade de P no solo com a adição de resíduos vegetais, tanto pelo P presente no resíduo como por competição de compostos orgânicos dos resíduos pelos sítios de troca no solo. A persistência dos compostos orgânicos também é fator que tem grande interferência nos processos de sorção/dessorção de cátions e ânions, dependendo da atividade microbiana, da disponibilidade metabólica do substrato carbonado e da sorção aos colóides do solo.
Resumo:
Avaliou-se o perfil sorológico de 17 bezerras búfalas vacinadas nos dias zero, 30 e 210 com bacterina pentavalente comercial contra leptospirose, empregando-se a prova de soroaglutinação microscópica com antígenos vivos, durante o período de 360 dias. Utilizaram-se quatro bezerras-controle, e todos os animais foram negativos no dia zero. Nos animais vacinados, foram observadas reações aos 60 dias para todos os sorovares, associadas a títulos máximos para Canicola, Grippothyphosa e Pomona. No 90° dia, houve declínio acentuado dos títulos para todos os sorovares e ausência de títulos para Hardjo. Nos dias 120º, 150º, 180º e 210º, ocorreram oscilações de títulos para todos os sorovares. No 240º dia, foram encontrados títulos máximos para Hardjo, elevação para os outros sorovares e ausência de título para Canicola. Nos dias 270º, 300º e 330º, foi observado declínio gradativo dos títulos. No 360º dia, foram encontrados títulos residuais para Icterohaemorrhagiae, Grippothyphosa e Pomona e ausência de reação para os outros sorovares. Inferiram-se a reduzida persistência dos títulos vacinais mesmo após o reforço e revacinação e a baixa interferência da vacinação no diagnóstico sorológico.
Resumo:
Cutaneous biopsies (n = 94) obtained from 88 patients with American tegumentary leishmaniasis were studied by conventional and immunohistochemical techniques. Specimens were distributed as active lesions of cutaneous leishmaniasis (n = 53) (Group I), cicatricial lesions of cutaneous leishmaniasis (n = 35) (Group II) and suggestive scars of healed mucosal leishmaniasis patients (n = 6) (Group III). In addition, active cutaneous lesions of other etiology (n = 24) (Group C1) and cutaneous scars not related to leishmaniasis (n = 10) (Group C2) were also included in the protocol. Amastigotes in Group I biopsies were detected by routine histopathological exam (30.2%), imprint (28.2%), culture (43.4%), immunofluorescence (41.4%) and immunoperoxidase (58.5%) techniques; and by the five methods together (79.3%). In Group II, 5.7% of cultures were positive. Leishmanial antigen was also seen in the cytoplasm of macrophages and giant cells (cellular pattern), vessel walls (vascular pattern) and dermal nerves (neural pattern). Positive reaction was detected in 49 (92.5%), 20 (57%) and 4 (67%) biopsies of Groups I, II and III, respectively. Antigen persistency in cicatricial tissue may be related to immunoprotection or, on the contrary, to the development of late lesions. We suggest that the cellular, vascular and neural patterns could be applied in the immunodiagnosis of active and cicatricial lesions in which leishmaniasis is suspected.
Resumo:
Conselho Nacional do Desenvolvimento Científico e Tecnológico (CNPq)