950 resultados para intraday seasonality


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Over the past decade, the diminishing Arctic sea ice has impacted the wave field, which depends on the ice-free ocean and wind. This study characterizes the wave climate in the Arctic spanning 1992–2014 from a merged altimeter data set and a wave hindcast that uses CFSR winds and ice concentrations from satellites as input. The model performs well, verified by the altimeters, and is relatively consistent for climate studies. The wave seasonality and extremes are linked to the ice coverage, wind strength, and wind direction, creating distinct features in the wind seas and swells. The altimeters and model show that the reduction of sea ice coverage causes increasing wave heights instead of the wind. However, trends are convoluted by interannual climate oscillations like the North Atlantic Oscillation (NAO) and Pacific Decadal Oscillation. In the Nordic Greenland Sea the NAO influences the decreasing wind speeds and wave heights. Swells are becoming more prevalent and wind-sea steepness is declining. The satellite data show the sea ice minimum occurs later in fall when the wind speeds increase. This creates more favorable conditions for wave development. Therefore we expect the ice freeze-up in fall to be the most critical season in the Arctic and small changes in ice cover, wind speeds, and wave heights can have large impacts to the evolution of the sea ice throughout the year. It is inconclusive how important wave–ice processes are within the climate system, but selected events suggest the importance of waves within the marginal ice zone.

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Respiratory syncytial virus (RSV) infection is the leading cause of hospitalisation for respiratory diseases among children under 5 years old. The aim of this study was to analyse RSV seasonality in the five distinct regions of Brazil using time series analysis (wavelet and Fourier series) of the following indicators: monthly positivity of the immunofluorescence reaction for RSV identified by virologic surveillance system, and rate of hospitalisations per bronchiolitis and pneumonia due to RSV in children under 5 years old (codes CID-10 J12.1, J20.5, J21.0 and J21.9). A total of 12,501 samples with 11.6% positivity for RSV (95% confidence interval 11 - 12.2), varying between 7.1 and 21.4% in the five Brazilian regions, was analysed. A strong trend for annual cycles with a stable stationary pattern in the five regions was identified through wavelet analysis of the indicators. The timing of RSV activity by Fourier analysis was similar between the two indicators analysed and showed regional differences. This study reinforces the importance of adjusting the immunisation period for high risk population with the monoclonal antibody palivizumab taking into account regional differences in seasonality of RSV.

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The hydroxyl radical (OH) removes most atmospheric pollutants from air. The loss frequency of OH radicals due to the combined effect of all gas-phase OH reactive species is a measureable quantity termed total OH reactivity. Here we present total OH reactivity observations in pristine Amazon rainforest air, as a function of season, time-of-day and height (0?80 m). Total OH reactivity is low during wet (10 s1) and high during dry season (62 s1). Comparison to individually measured trace gases reveals strong variation in unaccounted for OH reactivity, from 5 to 15% missing in wet-season afternoons to mostly unknown (average 79%) during dry season. During dry-season afternoons isoprene, considered the dominant reagent with OH in rainforests, only accounts for B20% of the total OH reactivity. Vertical profiles of OH reactivity are shaped by biogenic emissions, photochemistry and turbulent mixing. The rainforest floor was identified as a significant but poorly characterized source of OH reactivity.

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The seasonal climate drivers of the carbon cy- cle in tropical forests remain poorly known, although these forests account for more carbon assimilation and storage than any other terrestrial ecosystem. Based on a unique combina- tion of seasonal pan-tropical data sets from 89 experimental sites (68 include aboveground wood productivity measure- ments and 35 litter productivity measurements), their asso- ciated canopy photosynthetic capacity (enhanced vegetation index, EVI) and climate, we ask how carbon assimilation and aboveground allocation are related to climate seasonal- ity in tropical forests and how they interact in the seasonal carbon cycle. We found that canopy photosynthetic capacity seasonality responds positively to precipitation when rain- fall is < 2000 mm yr-1 (water-limited forests) and to radia- tion otherwise (light-limited forests). On the other hand, in- dependent of climate limitations, wood productivity and lit- terfall are driven by seasonal variation in precipitation and evapotranspiration, respectively. Consequently, light-limited forests present an asynchronism between canopy photosyn- thetic capacity and wood productivity. First-order control by precipitation likely indicates a decrease in tropical forest pro- ductivity in a drier climate in water-limited forest, and in cur- rent light-limited forest with future rainfall < 2000 mm yr-1.

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The aim of this study was to characterize the reproductive seasonality during the period of one year in Saanen goats managed in southeastern Brazil These results endorse hormonal methods (estrus synchronization and induction of synchronized estrus) or natural (male effect, flushing or light treatment) more appropriate according to the time of year in the region. Saanen goats, managed under tropical climate in southeastern Brazil, have a breeding season set from March until mid-August with the transitional phase to the anestrus in September. It is extends to mid-December at the new one transition phase for the reproductive season in March.

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To evaluate the oscillations on the viral detection in adenotonsillar tissues from patients with chronic adenotonsillar diseases as an indicia of the presence of persistent viral infections or acute subclinical infections. Cross-sectional prospective study. Tertiary hospital. The fluctuations of respiratory virus detection were compared to the major climatic variables during a two-year period using adenoids and palatine tonsils from 172 children with adenotonsillar hypertrophy and clinical evidence of obstructive sleep apnoea syndrome or recurrent adenotonsillitis, without symptoms of acute respiratory infection (ARI), by TaqMan real-time PCR. The rate of detection of at least one respiratory virus in adenotonsillar tissue was 87%. The most frequently detected viruses were human adenovirus in 52.8%, human enterovirus in 47.2%, human rhinovirus in 33.8%, human bocavirus in 31.1%, human metapneumovirus in 18.3% and human respiratory syncytial virus in 17.2%. Although increased detection of human enterovirus occurred in summer/autumn months, and there were summer nadirs of human respiratory syncytial virus in both years of the study, there was no obvious viral seasonality in contrast to reports with ARI patients in many regions of the world. Respiratory viruses are continuously highly detected during whole year, and without any clinical symptomatology, indicating that viral genome of some virus can persist in lymphoepithelial tissues of the upper respiratory tract.

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Although Brazil is the third largest fruit producer in the world, several specimens consumed are not well studied from the chemical viewpoint, especially for quantitative analysis. For this reason and the crescent employment of mass spectrometry (MS) techniques in food science we selected twenty-two phenolic compounds with important biological activities and developed an ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method using electrospray (ESI) in negative ion mode aiming their quantification in largely consumed Brazilian fruits (açaí-do-Amazonas, acerola, cashew apple, camu-camu, pineapple and taperebá). Multiple reaction monitoring (MRM) was applied and the selection of proper product ions for each transition assured high selectivity. Linearity (0.995intraday accuracy (>80%), precision (CV<20%) and extraction recovery rate (>80%) were satisfactory and showed that the method provides an efficient protocol to analyze phenolic compounds in fruit pulp extracts.

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The composition and biological activities of propolis, a resinous hive product collected by honeybees from various plant sources, depends on various factors such as season and vegetation of the area. The aim of this study was to evaluate the influence of the seasonal effect on the ethanolic extracts of Brazilian propolis (EEP) type 6 and type 12, collected during 6 months in terms of antibacterial activity and phenolic composition. The antimicrobial properties were evaluated by MIC and MBC on S. mutans Ingbritt 1600 and the profile of chemical composition by UV-visible spectrophotometry, HPLC-RF and GC-MS. The results demonstrated that the season in which propolis is collected influences its chemical composition, resulting in modifications in its antibacterial activity.

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O domínio do Cerrado compreende uma área contínua nos estados centrais do Brasil e áreas disjuntas em outros estados, incluindo São Paulo. Essa vegetação ocupava originalmente 21% do território brasileiro, restando atualmente apenas 21,6% de sua extensão original. A área recoberta por essa vegetação em São Paulo cobria 14% de sua área total e seus remanescentes recobrem menos de 1% da ocorrência original dessa vegetação. Estudos recentes indicam que o valor da produtividade líquida no Cerrado Pé-de-Gigante (SP) constitui um pequeno dreno de carbono e indicou que a sazonalidade foi o fator determinante do valor observado. Os estudos dos fluxos de carbono em ecossistemas terrestres são raramente acompanhados de abordagens ecofisiológicas de modo a explorar a relação funcional das espécies que compõem o ecossistema e os valores líquidos obtidos para o mesmo. Assim, o objetivo deste trabalho foi caracterizar estruturalmente a vegetação presente na área de maior influência da torre de fluxo instalada no Cerrado Pé-de-Gigante, visando possibilitar estudos relacionados à quantificação em longo prazo da dinâmica dos fluxos de água, energia e CO2 na vegetação de Cerrado. Para isso foram levantadas 20 parcelas (10 x 10 m) em 0,2 ha de Cerrado, e amostraram-se todas as plantas com perímetro ao nível do solo >6 cm (exceto lianas e árvores mortas). A distribuição das classes de diâmetro e estrutura vertical, assim como os parâmetros fitossociológicos foram analisados. Encontramos 1451 indivíduos, distribuídos em 85 espécies, 52 gêneros e 31 famílias. A densidade absoluta e área basal foram de 7255 ind. ha-1 e de 7,9 m².ha-1, respectivamente. A família Leguminosae apresentou o maior número de espécies (13). O Índice de diversidade de Shannon (H') foi 3,27 nats.ind-1. A distribuição em classes de diâmetro mostrou uma curva de "J" invertido, estando a maioria dos indivíduos na primeira classe. Concluímos que a área deve ser classificada como Cerrado denso, devido principalmente à dominância pela espécie arbórea Anadenanthera falcata, cuja ocorrência no estado foi relatada apenas em locais com solos ricos em saturação de bases na região das Cuestas Basálticas, devido também à maior área basal dos indivíduos, comparando com outros fragmentos de Cerrado. Além da espécie citada, Myrcia lingua e Xylopia aromatica, apresentaram os maiores IVI (Valor de importância).

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OBJETIVO: Este artigo analisa e compara os dados de consumo alimentar de duas populações ribeirinhas da Amazônia vivendo em ecossistemas contrastantes de floresta tropical: a várzea estacional e a floresta de terra firme. MÉTODOS: Foi estudado o consumo alimentar de 11 unidades domésticas na várzea (Ilha de Ituqui, Município de Santarém) e 17 na terra firme (Floresta Nacional de Caxiuanã, Municípios de Melgaço e Portel). O método utilizado foi o recordatório de 24 horas. As análises estatísticas foram executadas com o auxílio do programa Statistical Package for Social Sciences 12.0. RESULTADOS: Em ambos os ecossistemas, os resultados confirmam a centralidade do pescado e da mandioca na dieta local. Porém, a contribuição de outros itens alimentares secundários, tais como o açaí (em Caxiuanã) e o leite in natura (em Ituqui), também foi significante. Além disso, o açúcar revelou ser uma fonte de energia confiável para enfrentar as flutuações sazonais dos recursos naturais. Parece haver ainda uma maior contribuição energética dos peixes para a dieta de Ituqui, provavelmente em função da maior produtividade dos rios e lagos da várzea em relação à terra firme. Por fim, Ituqui revelou uma maior dependência de itens alimentares comprados, enquanto Caxiuanã mostrou estar ainda bastante vinculada à agricultura e às redes locais de troca. CONCLUSÃO: Além dos resultados confirmarem a importância do pescado e da mandioca, também mostraram que produtos industrializados, como o açúcar, têm um papel importante nas dietas, podendo apontar para tendências no consumo alimentar relacionadas com a atual transição nutricional e com a erosão, em diferentes níveis, dos sistemas de subsistência locais.

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Este trabalho tem por objetivo identificar e caracterizar as feições oceanográficas de pequena e mesoescala que ocorrem na plataforma continental de Santa Catarina (SC). Foram empregadas imagens de temperatura e concentração de clorofila da superfície do mar (TSM e CSM), obtidas pelo sensor MODIS. Foi selecionada uma imagem diária para cada mês do ano de 2003, excetuando dezembro, onde procurou-se avaliar efeitos sazonais. As feições oceanográficas foram observadas através da aplicação de diferentes níveis de contraste e paletas de cores para realce. Foram identificadas feições como vórtices, meandros, cogumelos, plumas, filamentos, frentes e áreas de ressurgências. Os resultados indicam que no verão a distribuição superficial em mesoescala da temperatura é mais homogênea, levando a um número menor de feições observáveis. O fenômeno de ressurgência costeira em escala localizada ao sul da Ilha de SC e junto à costa foi observado nos meses de novembro, janeiro e fevereiro. Durante o outono e o inverno as imagens apresentaram maior grau de complexidade, principalmente devido à presença da frente costeira do Prata, com características de menor temperatura e maiores valores de clorofila.

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Many species in the genus Sporophila are migratory. Migration patterns, while poorly studied, may be influenced by seed production which can be very seasonal in some regions. The distribution of S. bouvreuil extends from the Amazon and Suriname south through a large part of the open regions of Brazil. Sporophila pileata, on the other hand, is found in southeastern and southern Brazil as well as Argentina and Paraguay. Both of these species migrate, but their movement patterns are poorly known. To better understand the geographical and the seasonal distributions of S. bouvreuil and S. pileata, we grouped the records into two categories: the breeding season (September to March) and the putative migration season (April to August). We found two areas of sympatry between S. bouvreuil and S. pileata in the Brazilian states of Minas Gerais and São Paulo. For S. bouvreuil we suggest that populations that breed in the Amazon migrate to the Cerrado or Caatinga, where they will encounter resident populations of the same species. These resident populations may take part in short distance migrations. Sporophila pileata, on the other hand, occur in the Cerrado and open areas within the Atlantic Forest and it is not yet possible to determine migratory tendencies or destinations in the non-breeding season.

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OBJETIVO: Avaliar a prevalência e a sazonalidade do vírus respiratório sincicial humano (VRSH) em crianças de 0 a 6 anos hospitalizadas por infecção aguda das vias aéreas inferiores (IVAI) em São José do Rio Preto (SP) e a associação entre faixa etária, diagnóstico e VRSH. MÉTODOS: Entre maio de 2004 e setembro de 2005, foram estudados 290 episódios consecutivos de IVAI adquiridos na comunidade em crianças de 0 a 6 anos internadas no Hospital de Base de São José do Rio Preto. Para identificação do VRSH, foram coletadas amostras de secreção de nasofaringe e realizou-se análise molecular por meio da técnica de RT-PCR. RESULTADOS: A prevalência de VRSH foi de 29,3% nos episódios de IVAI hospitalizados. A IVAI foi frequente em lactentes (mediana de idade = 13,5 meses). O VRSH foi mais frequente nos casos de bronquiolite (64%) e no primeiro ano de vida (35%). Os episódios de infecção por VRSH ocorreram entre o outono e a primavera, com frequência maior em 2004 do que em 2005. Os critérios clínicos e radiológicos não foram suficientes para o diagnóstico de infecção pelo VRSH. Em 78,8% dos episódios de VRSH, houve tratamento com antibiótico. CONCLUSÕES: A prevalência do VRSH em crianças de 0 a 6 anos hospitalizadas por IVAI foi elevada, com predomínio nas mais jovens ou com bronquiolite. A circulação do vírus variou nos dois anos estudados. Os resultados sugerem necessidade de diagnóstico laboratorial do VRSR na prática clínica.

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American cutaneous leishmaniasis (ACL) occurs in epidemic outbreaks and in sporadic cases with small annual variation in the Pontal of Paranapanema, SP. There is little research on the sandfly fauna of this region. The last outbreaks were related to the Movement of the Landless Workers (MST) and with the ecological tourism in preserved forest of the Parque Estadual do Morro do Diabo (PEMD). AIM: identification of the sandfly fauna within the PEMD, mainly anthropophilic species already incriminated as vectors of ACL, as well as their seasonality, hourly frequency and data of the behavior. M&M: The captures were undertaken with CDC light and Shannon traps from 6:00 pm to 10:00 pm, monthly from May 2000 to December 2001. The temperature and relative humidity data were registered at hourly intervals. RESULTS: The captured species were: Brumptomyia brumpti, Nyssomyia neivai, Nyssomyia whitmani, Pintomyia fischeri and Pintomyia pessoai. The P. pessoai predominated (34.39%) and N. neivai was less found (0.74%), only being captured in CDC traps. Shannon trap captured more sandflies (63.01%) than the CDC traps (36.99%). Despite the environmental degradation anthropophilic species, indicates favorable bioecological conditions for persistence of vectors and potential transmission of leishmaniasis.