977 resultados para Normalize different vegetation indices
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Este trabalho tem como objetivo a comparação da intensidade, frequência e distribuição de um conjunto de índices de estabilidade atmosférica simulados entre o clima histórico (1986-2005) e um cenário climático (2081-2100) na Península Ibérica. Considerou-se o cenário de emissão de gases RCP8.5. Estes índices avaliam a instabilidade atmosférica que é um elemento fundamental e percursor no desenvolvimento de tempestades. Através dos seus valores limite, é possível estimar alterações na probabilidade de ocorrência de eventos extremos que se poderão desenvolver no clima futuro, relativamente ao histórico. Primeiro, utilizou-se um conjunto de simulações do WRF com dois forçamentos: reanálises do ERA-Interim e um modelo do Max Planck Institute. De seguida, foram calculados diferentes índices de estabilidade. A validação do modelo consistiu no cálculo das médias sazonais, da sua diferença e das respetivas PDFs dos índices simulados pelo WRF-MPI e WRF-ERA. Verifica-se uma sobrestimação do CAPE, SHR6km (vento de corte) e SWEAT simulados pelo WRF-MPI. No entanto, nos campos dos índices simulados pelos dois forçamentos para o período histórico, verifica-se que os padrões espaciais são semelhantes apesar das diferenças na intensidade. Como as alterações climáticas dos índices são avaliadas através de diferenças, estas discrepâncias não invalidam a utilização do modelo no futuro. Posteriormente foram estudadas as alterações climáticas dos índices através da comparação entre o clima histórico e futuro. Estima-se um aumento da intensidade do CAPE e uma diminuição (aumento) da frequência de eventos com intensidade reduzida (elevada). Estas alterações são robustas no verão e outono. Também é esperado um aumento da intensidade do SHR6km na primavera e inverno tal como da frequência de SHR6km elevado nestas estações e uma redução da intensidade e da frequência de eventos com SHR6km elevado nas restantes. Haverá um possível aumento robusto da intensidade do SWEAT no verão e outono, bem como da frequência destes valores. Concluindo, será provável um aumento da frequência dos ambientes favoráveis ao desenvolvimento de tempestades, devido a uma maior intensidade e probabilidade de ocorrência de valores extremos do CAPE e do SWEAT. No entanto, a redução do SHR6km, poderá diminuir a organização das tempestades e o seu tempo de vida.
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Many photonic devices are based on waveguides (WG) whose optical properties can be externally modified. These active WGs are usually obtained with electrooptic materials in either the propagating film (core) or the substrate (cladding). In the second case, the WG tunability is based on the interaction of the active material with the evanescent field of the propagating beam.Liquid crystals (LCs) are an excellent choice as electrooptic active materials since they feature high birefringence, low switching voltage, and relatively simple manufacturing. In this work, we have explored alternative ways to prepare WGs of arbitrary shapes avoiding photolithographic steps. To do this, we have employed a UV laser unit (Spectra Physics)attached to an xyzCNC system mounted on an optical bench. The laser power is 300mW, the spot size can be reduced slightly below 1 µm, and the electromechanicalpositioning is well below that number.Different photoresinshave been evaluated for curing time and uniformity; the results have been compared to equivalent WGs realized by standard photolithographic procedures. Best results have been obtained with several kinds of NOA adhesives (Norland Products Inc.) and SU8 (Microchem). NOA81 optical adhesive has been employed by several groups for the preparation ofmicrochannels [1] and microfluidic systems[2]. In our case, several NOAs having different refractive indices have been tested in order to optimize light coupling and guiding. The adhesive is spinnedonto a substrate, and a number of segmented WGs are written with the laser system. The laser power is attenuated 20 dB. Then the laser spot is swept a number of times (from 1 to 900) on every segment. It has been found that, for example, the optimum number of sweeps for NOA81 is 30-70 times (center of the figure) under these conditions. The WG dimensions obtained with this procedure are about 7 µm high and 12 µm wide.
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Mastitis negatively influences the survival and weight gain of ovines for meat production. The purpose of this study was to investigate, in sheep for meat production, the occurrence of subclinical mastitis in ewes at the end of lactation and beginning of the consecutive lactation and to assess the composition and cellular characteristics of milk as a function of different rainfall indices. Mammary halves (821) of Santa Ines (479) and Morada Nova (342) ewes were examined. Milk samples were collected in two different moments of lactation: at weaning and postpartum of the consecutive lactation. Sample collection periods were called ?dry? or ?rainy? according to the rainfall index in the month immediately before the month of collection. The occurrence of subclinical mastitis at weaning in the Santa Ines and Morada Nova ewes were 16.4 and 12.6% in the dry period, and 17.7 and 23.5% in the rainy period, respectively. In the consecutive lactation period, the occurrences were 26.7 and 27.7% in the dry period and 41.8 and 39.1% in the rainy period, for the Santa Ines and Morada Nova ewes, respectively. Postpartum stage was critical for the occurrence of subclinical mastitis, as compared to that at the end of the previous lactation. Occurrence of the disease negatively influenced the SCC in the milk at the beginning of lactation and changed its composition, mainly in the rainiest periods, probably due to a difficulty in maintaining hygiene in the environment where the animals remained.
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The purpose of this work was to investigate possible patterns occurring in the sewage bacterial content of four cities (Bologna, Budapest, Rome, Rotterdam) over time (March 2020 - November 2021), also considering the possible effects of the lockdown periods due to the COVID-19 pandemic. The sewage metagenomics data were provided within VEO (Versatile Emerging infectious disease Observatory) project. The first analysis was the evaluation of the between samples diversity, looking for (dis)similarities among the cities, as well as among different time periods (seasonality). To this aim, we computed both similarity networks and Principal Coordinate Analysis (PCoA) plots based on the Bray-Curtis metric. Then, the alpha-biodiversity of the samples was estimated by means of different diversity indices. By looking at the temporal behaviour of the biodiversity in the four cities, we noticed an abrupt decrease in both Rome and Budapest in the Summer of 2020, that is related to: the prevalence of some species when the minimum occurred, and the change in correlations among species (studied via correlation networks), which is enriched in the period of minimum biodiversity. Rotterdam samples seem to be very different with respect to those from the other cities, as confirmed by PCoA. Moreover, the Rotterdam time series is proved to be stable and stationary also in terms of biodiversity. The low variability in the Rotterdam samples seems to be related to the species of Pseudomonas genus, which are highly variable and plentiful in the other cities, but are not among the most abundant in Rotterdam. Also, we observed that no seasonality effect emerged from the time series of the four cities. Regarding the impact of lockdown periods due to the COVID-19 pandemic, from the limited data available no effect on the time series considered emerges. More samples will be soon available and these analyses will be performed also on them, so that the possible effects of lockdowns may be studied.
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OBJECTIVE: To compare the accuracy of 4 different indices of cardiac risk currently used for predicting perioperative cardiac complications. METHODS: We studied 119 patients at a university-affiliated hospital whose cardiac assessment had been required for noncardiac surgery. Predictive factors of high risk for perioperative cardiac complications were assessed through clinical history and physical examination, and the patients were followed up after surgery until the 4th postoperative day to assess the occurrence of cardiac events. All patients were classified according to 4 indices of cardiac risk: the Goldman risk-factor index, Detsky modified risk index, Larsen index, and the American Society of Anesthesiologists' physical status classification and their compared accuracies, examining the areas under their respective receiver operating characteristic (ROC) curves. RESULTS: Cardiac complications occurred in 16% of the patients. The areas under the ROC curves were equal for the Goldman risk-factor index, the Larsen index, and the American Society of Anesthesiologists' physical status classification: 0.48 (SEM ± 0.03). For the Detsky index, the value found was 0.38 (SEM ± 0.03). This difference in the values was not statistically significant. CONCLUSION: The cardiac risk indices currently used did not show a better accuracy than that obtained randomly. None of the indices proved to be significantly better than the others. Studies to improve our ability to predict such complications are still required.
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Generally, in tropical and subtropical agroecosystems, the efficiency of nitrogen (N) fertilization is low, inducing a temporal variability of crop yield, economic losses, and environmental impacts. Variable-rate N fertilization (VRF), based on optical spectrometry crop sensors, could increase the N use efficiency (NUE). The objective of this study was to evaluate the corn grain yield and N fertilization efficiency under VRF determined by an optical sensor in comparison to the traditional single-application N fertilization (TSF). With this purpose, three experiments with no-tillage corn were carried out in the 2008/09 and 2010/11 growing seasons on a Hapludox in South Brazil, in a completely randomized design, at three different sites that were analyzed separately. The following crop properties were evaluated: aboveground dry matter production and quantity of N uptake at corn flowering, grain yield, and vegetation index determined by an N-Sensor® ALS optical sensor. Across the sites, the corn N fertilizer had a positive effect on corn N uptake, resulting in increased corn dry matter and grain yield. However, N fertilization induced lower increases of corn grain yield at site 2, where there was a severe drought during the growing period. The VRF defined by the optical crop sensor increased the apparent N recovery (NRE) and agronomic efficiency of N (NAE) compared to the traditional fertilizer strategy. In the average of sites 1 and 3, which were not affected by drought, VRF promoted an increase of 28.0 and 41.3 % in NAE and NRE, respectively. Despite these results, no increases in corn grain yield were observed by the use of VRF compared to TSF.
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The concept of soil quality is currently the subject of great discussion due to the interaction of soil with the environment (soil-plant-atmosphere) and practices of human intervention. However, concepts of soil quality relate quality to agricultural productivity, but assessment of soil quality in an agronomic context may be different from its assessment in natural areas. The aim of this study was to assess physical quality indices, the S index, soil aeration capacity (ACt/Pt), and water storage capacity (FC/Pt) of the soil from a permanent plot in the Caetetus Ecological Reserve (Galia, São Paulo, Brazil) under a seasonal semideciduous forest and compare them with the reference values for soil physical quality found in the literature. Water retention curves were used for that purpose. The S values found were higher than the proposed limit for soil physical quality (0.035). The A and E horizons showed the highest values because their sandy texture leads to a high slope of the water retention curve. The B horizons showed the lowest S values because their natural density leads to a lower slope of the water retention curve. The values found for ACt/Pt and FC/Pt were higher and lower than the idealized limits. The values obtained from these indices under natural vegetation can provide reference values for soils with similar properties that undergo changes due to anthropic activities. All the indices evaluated were effective in differentiating the effects of soil horizons in the natural hydro-physical functioning of the soils under study.
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Tiivistelmä: Turpeen ominaisuudet ja kasvillisuus metsitetyn ja lannoitetun avosuon eri trofiatasoilla
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The objective of this study was to establish critical values of the N indices, namely soil-plant analysis development (SPAD), petiole sap N-NO3 and organic N in the tomato leaf adjacent to the first cluster (LAC), under soil and nutrient solution conditions, determined by different statistical approaches. Two experiments were conducted in randomized complete block design with four repli-cations. Tomato plants were grown in soil, in 3 L pot, with five N rates (0, 100, 200, 400 and 800 mg kg-1) and in solution at N rates of 0, 4, 8, 12 and 16 mmol L-1. Experiments in nutrient solution and soil were finished at thirty seven and forty two days after transplanting, respectively. At those times, SPAD index and petiole sap N-NO3 were evaluated in the LAC. Then, plants were harvested, separated in leaves and stem, dried at 70ºC, ground and weighted. The organic N was determined in LAC dry matter. Three statistical procedures were used to calculate critical N values. There were accentuated discrepancies for critical values of N indices obtained with plants grown in soil and nutrient solution as well as for different statistical procedures. Critical values of nitrogen indices at all situations are presented.
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Reaching a consensus in terms of interchangeability and utility (i.e., disease detection/monitoring) of a medical device is the eventual aim of repeatability and agreement studies. The aim of the tolerance and relative utility indices described in this report is to provide a methodology to compare change in clinical measurement noise between different populations (repeatability) or measurement methods (agreement), so as to highlight problematic areas. No longitudinal data are required to calculate these indices. Both indices establish a metric of least to most effected across all parameters to facilitate comparison. If validated, these indices may prove useful tools when combining reports and forming the consensus required in the validation process for software updates and new medical devices.
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Among the building materials used in rural facilities, roofs are noteworthy for being largely responsible for thermal comfort, influencing the thermal balance within the shelter. This study aimed to evaluate the influence of roof on the Enthalpy (H), Thermal Load of Radiation (TLR), and Black Globe Temperature and Humidity Index (BGHI) in individual shelters for dairy calves. The design was completely randomized with three treatments: Z - zinc tile, AC - asbestos-cement tile and ACW - asbestos-cement tile painted white on the upper side. The averages were compared by the Scott Knott test at 1% probability. The results showed no statistical difference between treatments (P<0.01) and the external environment for H. For TLR, there was statistical difference among all treatments, where ACW showed the lowest TLR, 489.28 W m-2, followed by AC with 506.72 W m-2 and Z with the highest TLR, 523.55 W m-2. For BGHI, the lowest values were observed for ACW (76.8) and AC (77.4), differing significantly from Z, which obtained the highest value (81.6). The tiles with white paint on the upper side promoted the lowest TLR and the lowest BGHI, favoring the thermal environment in the shelter.
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This research aims at studying spatial autocorrelation of Landsat/TM based on normalized difference vegetation index (NDVI) and green vegetation index (GVI) of soybean of the western region of the State of Paraná. The images were collected during the 2004/2005 crop season. The data were grouped into five vegetation index classes of equal amplitude, to create a temporal map of soybean within the crop cycle. Moran I and Local Indicators of Spatial Autocorrelation (LISA) indices were applied to study the spatial correlation at the global and local levels, respectively. According to these indices, it was possible to understand the municipality-based profiles of tillage as well as to identify different sowing periods, providing important information to producers who use soybean yield data in their planning.
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This study analyzes evapotranspiration data for three wet and two seasonally dry rain forest sites in Amazonia. The main environmental (net radiation, vapor pressure deficit, and aerodynamic conductance) and vegetation (surface conductance) controls of evapotranspiration are also assessed. Our research supports earlier studies that demonstrate that evapotranspiration in the dry season is higher than that in the wet season and that surface net radiation is the main controller of evapotranspiration in wet equatorial sites. However, our analyses also indicate that there are different factors controlling the seasonality of evapotranspiration in wet equatorial rain forest sites and southern seasonally dry rain forests. While the seasonality of evapotranspiration in wet equatorial forests is driven solely by environmental factors, in seasonally dry forests, it is also biotically controlled with the surface conductance varying between seasons by a factor of approximately 2. The identification of these different drivers of evapotranspiration is a major step forward in our understanding of the water dynamics of tropical forests and has significant implications for the future development of vegetation-atmosphere models and land use and conservation planning in the region.
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Dentre os materiais de construção utilizados nas instalações rurais, merecem destaque as coberturas, pois são grandes responsáveis pelo conforto térmico, influenciando no balanço térmico no interior das instalações. Este trabalho objetivou avaliar a influência das coberturas sobre a entalpia (H), Carga Térmica Radiante (CTR) e no Índice de Temperatura de Globo Negro e Umidade (ITGU), em abrigos individuais para bezerros leiteiros. O delineamento foi o inteiramente casualizado com três tratamentos: Z - telha de zinco; CA - telha de cimento amianto, e CAB - telha de cimento amianto pintada de branco na face superior. As médias foram comparadas pelo teste de Scott Knott, a 1% de probabilidade. Os resultados mostraram que não houve diferença estatística entre os tratamentos (P<0,01) e o ambiente externo, para a H. Para a CTR, houve diferença estatística entre todos os tratamentos, em que CAB demonstrou menor CTR, 489,28 W m-², seguido do tratamento CA, 506,72 W m-², e Z com maior valor de CTR, 523,55 W m-². Para o ITGU, observaram-se menores valores para CAB (76,8) e CA (77,4), diferindo-se, significativamente do Z, que obteve maior valor (81,6). As telhas com pintura branca em sua face superior promoveram menor CTR e menor ITGU, favorecendo o ambiente térmico da instalação.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)