3,830 research outputs found
Crescimento e dinâmica foliar de duas espécies de Cecropia
Allometry, growth and leaf demography of two Cecropia species, one with ant mutualist (C. glazioui) and another without it (C. hololeuca), were studied in an Atlantic Rain Forest area in the State of Rio de Janeiro, SE Brazil. Stem diameter was allometrically related to height in both species. Cecropia glazioui showed higher annual growth rates and longer internodes than C. hololeuca. Leaf phenology showed a seasonal pattern in both species, but the number of leaves on each plant was more variable along the year in C. hololeuca than in C. glazioui. Survivorship curves for leaves were intermediate between Deevey's Type I and Type II curves, with young leaves of C. glazioui showing a greater survival rate and life expectancy than those of C. hololeuca. Low variability in leaf production throughout the year and high survival rate for young leaves of C. glazioui may be characteristics related to its association with ants.Alometria, crescimento e demografia de folhas de uma espécie de Cecropia associada com formigas (C. glazioui) e outra não (C. hololeuca) foram estudadas em área de Floresta Pluvial Atlântica, no SE Brasil. As relações entre os diâmetros dos caules e as alturas das plantas foram semelhantes nas duas espécies. Cecropia glazioui apresentou maior crescimento anual e entrenós maiores que C. hololeuca. A emergência e a mortalidade de folhas foram sazonais nas duas espécies, sendo o número de folhas mais variável ao longo do ano em C. hololeuca que em C. glazioui. As curvas de sobrevivência de folhas foram intermediárias entre os Tipo I e Tipo II de Deevey, sendo que folhas jovens de C. glazioui apresentam probabilidades de sobrevivência e expectativas de vida maiores que as de C. hololeuca. A produção de folhas menos variável durante o ano, e a maior sobrevivência de folhas novas em C. glazioui podem estar relacionadas à associação com formigas.133141Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq
SSA of biomedical signals: A linear invariant systems approach
Singular spectrum analysis (SSA) is considered from a linear invariant systems perspective. In this terminology, the extracted components are considered as outputs of a linear invariant system which corresponds to finite impulse response (FIR) filters. The number of filters is determined by the embedding dimension.We propose to explicitly define the frequency response of each filter responsible for the selection of informative components. We also introduce a subspace distance measure for clustering subspace models. We illustrate the methodology by analyzing lectroencephalograms (EEG).FCT - PhD scholarship (SFRH/BD/28404/2006)FCT - PhD scholarship (SFRH/BD/48775/2008
Intercellular communication between osteocytes and stem cells:implications for bone tissue engineering
Relações Comprimento-peso Da Ictiofauna De Um Sistema Costeiro Subtropical: Uma Ferramenta Para Estimativas De Biomassa E Modelagem De Ecossistemas
Aiming to analyse the growth pattern, to allow biomass estimates and consequently to subsidize the ecosystem modelling, the length-weight relationships (LWR) of 39 fish species from the Araçá Bay, a subtropical coastal area chosen as model for a holistic study comprising environmental, social and economic aspects have been estimated. The objective of this study was to provide LWR for the fishes from the area itself, accurately based on the life stages of fish populations present there. Particularly for Albula vulpes, Trachinotus carolinus, T. falcatus, Archosargus rhomboidalis and Kyphosus sectatrix these are the first records of LWR in Brazil. © 2016, Universidade Estadual de Campinas UNICAMP. All rights reserved.16
Intercellular communication between osteocytes and stem cells:implications for bone tissue engineering
Identifying evoked potential response patterns using independent component analysis and unsupervised learning
Independent Component Analysis(ICA) is a pre-processing step widely used in brain studies. One of
the most common problems in artifact elimination or brain activity related studies is the ordering and
identification of the independent components(ICs). In this work, a novel procedure is proposed
which combines ICA decomposition at trial level with an unsupervised learning algorithm (K-means)
at participant level in order to enhance the related signal patterns which might represent interesting
brain waves. The feasibility of this methodology is evaluated with EEG data acquired with participants
performing on the Halstead Category Test. The analysis shows that it is possible to find the Feedback
Error Negativity (FRN) Potential at single-trial level and relate its characteristics with the performance
of the participant based on their knowledge of the abstract principle underlying the task.info:eu-repo/semantics/publishedVersio
EPIC-PHASE: a model to explore irrigation strategies
bstract
The erosion productivity impact calculator phase (EPIC-PHASE) model has been used to simulate, using 1972 to 1994 climatic date, two irrigation strategies with a non-limited water supply: (1) a standard strategy based on simple decision rules advisable for moderately deep soils of the Lauragais region (France) and in the Alentejo region (Portugal); and (2) a model strategy based on the daily development of soil water depletion and daily water stress intensity predicted by the model. At Lauragais, the results show that for the same level of yield it would have been possible with the model to save 73 mm on average, equivalent of two irrigations per year, compared to the standard strategy. These savings are due to an increased soil water contribution during the cycle and to an earlier end of the irrigation supply. At Alentejo, the results show that for the same level of yield as obtained with the standard strategy, it would have been possible with EPIC-PHASE model to save 100 mm of water on average, equivalent of two irrigations per year due to an increased use of soil water during the cycle. Although the results are from simulations it is proved that the standard strategy is inadequate. Regarding the environmental impact, the model management allows for an increase in the level of water depletion at harvest, delaying the risk of percolation and nitrogen losses during the refill period. The EPIC-PHASE model proved to be a tool capable of defining an irrigation schedule better adapted to the Mediterranean region
Photo and electroluminescence behavior of Tb(ACAC)3phen complex used as emissive layer on organic light emitting diodes
This work shows the luminescence properties of a rare-earth organic complex, the Tb(ACAC)3phen. The results show the 5D4 -> 7F3,4,5,6 transitions with no influence of any ligand emission. The photoluminescence excitation spectrum is tentatively interpreted by the ligands absorption. An OLED was made by thermal evaporation (total thickness of 1200 Å) using TPD and Alq3 as hole and electron transport layers, respectively. The light emission reproduces the photoluminescence spectrum of the terbium complex at room temperature, with CIE (x,y) color coordinates of (0.28, 0.55). No presence of any bands from the ligands was observed. The potential use of this compound in efficient devices is discussed
Three-dimensional track reconstruction for directional Dark Matter detection
Directional detection of Dark Matter is a promising search strategy. However,
to perform such detection, a given set of parameters has to be retrieved from
the recoiling tracks : direction, sense and position in the detector volume. In
order to optimize the track reconstruction and to fully exploit the data of
forthcoming directional detectors, we present a likelihood method dedicated to
3D track reconstruction. This new analysis method is applied to the MIMAC
detector. It requires a full simulation of track measurements in order to
compare real tracks to simulated ones. We conclude that a good spatial
resolution can be achieved, i.e. sub-mm in the anode plane and cm along the
drift axis. This opens the possibility to perform a fiducialization of
directional detectors. The angular resolution is shown to range between
20 to 80, depending on the recoil energy, which is however
enough to achieve a high significance discovery of Dark Matter. On the
contrary, we show that sense recognition capability of directional detectors
depends strongly on the recoil energy and the drift distance, with small
efficiency values (50%-70%). We suggest not to consider this information either
for exclusion or discovery of Dark Matter for recoils below 100 keV and then to
focus on axial directional data.Comment: 27 pages, 20 figure
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