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Couprie M.,University Paris Est Creteil | Bezerra N.,Instituto Federal do Ceara | Bertrand G.,University Paris Est Creteil
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2013

Grayscale skeletonization offers an interesting alternative to traditional skeletonization following a binarization. It is well known that parallel algorithms for skeletonization outperform sequential ones in terms of quality of results, yet no general and well defined framework has been proposed until now for parallel grayscale thinning. We introduce in this paper a parallel thinning algorithm for grayscale images, and prove its topological soundness based on properties of the critical kernels framework. The algorithm and its proof, given here in the 2D case, are also valid in 3D. Some applications are sketched in conclusion. © 2013 Springer-Verlag Berlin Heidelberg. Source


de Medeiros D.C.,UFERSA | de Medeiros J.F.,UFERSA | Pereira F.A.L.,UFERSA | de Souza R.O.,UFERSA | de Souza P.A.,Instituto Federal do Ceara
Revista Caatinga | Year: 2011

In recent years an increase of 15 to 20% occurred in market share melons like Cantaloupes group, which present more attractive organoleptic characteristics and higher commercial value. However it needs more care in production due its higher sensitivity to soil salinity. Effects of soil and water salinity are among the main limiting factors to melon yield and quality at Rio Grande do Norte Sate, Brazil. This work was carried out with the objective of studying the effect of different irrigation water salinity levels on yield and quality of cantaloupe hybrid 'Sedna'. Experimental design was a randomized complete blocks with four replications. Treatments consisted of five salt concentrations in irrigation water (0.54; 1.48; 2.02; 3.03 and 3.9 dS m -1). Yield and quality characteristics evaluated were: number of marketable fruits per plant, yield of marketable fruits, mean weight of fruits, soluble solids content (SS) and pulp firmness. An increase on irrigation water salinity level negatively influenced yield of melon hybrid 'Sedna'. Yield loss in response to salinity was due to decrease in number of fruits per plant. Mean values of soluble solids and pulp firmness were not influenced by irrigation water salinity. Source


De Farias S.G.G.,Federal University of Piaui | Rodal M.J.N.,University of Pernambuco | de Melo A.L.,University of Pernambuco | Silva M.A.M.,Instituto Federal do Ceara | de Lima A.L.A.,University of Pernambuco
Ciencia Florestal | Year: 2016

This study aimed to investigate the influence of spatial heterogeneity of abiotic factors on the spatial patterns of vegetation structure of the woody component and of its regeneration; it was carried out in an area of “caatinga” located in the Parque Estadual Mata of Pimenteira, municipality of “Serra Talhada”, interior of Pernambuco State, Brazil. The sample was divided into two environments, one near the watercourse with denser vegetation (I) and another at 100 meters away from the watercourse with more open vegetation (II). In each environment, four permanent plots of 20×50 m were installed and divided into ten plots of 10×10 m; alive individuals with stem ground level diameter (GD) of ≥3 cm and total height of ≥1 m were measured. In one corner of each plot, a sub-plot of 2×2 m was allocated to measure the individuals’ height and diameter of the sampled species in woody component with GD from 0.5 to 2.9 cm (regeneration). Community’s general phytosociological descriptors of the different environments were calculated and the individuals’ distribution in histograms was evaluated for the woody component as for regeneration. After testing for normality using Kolmogorov-Smirnov test, values of phytosociological descriptors per plot were compared between the environments. Analysis of variance (ANOVA) of a criterion was used for data with normal distribution. Data without normal distribution were analyzed by non-parametric Mann-Whitney test. Environments showed significant differences in the number of individuals (4047.5 versus 3332.5 ind.ha-1) and basal area (23.6 versus 17.6 m2. ha-1) with significantly higher values in environment I; this pattern was opposite to the regenerating pattern in which the number of individuals and basal area were higher in the environment II (9187.5 vs. 10937.5 ind.ha-1 and 1.9 vs. 2.5 m2.ha-1, respectively). In total, fifty species, including woody and regenerating component, were sampled; significant differences in diversity were found between environments in the different strata, although the similarity was more than 80%. Most chemical and textural soil variables did not differ statistically, except for levels of A3+, which showed higher levels in the environment I. Among other edaphic variables, only the stony variables differed between environments I and II (3.87 versus 1.47%). The vegetation physiognomic distinction between the environments is result from populations’ presence of individuals with greater heights and diameters in the environment I. The spatial heterogeneity of environmental variables found in the studied environments explained part of changes in floristic and structural characteristics of the vegetation. © 2016, Universidade Federal de Santa Maria. All Rights Reserved. Source


de Oliveira Fernandes P.L.,Pos Graduacao em Fitotecnia | Aroucha E.M.M.,Pos Graduacao em Fitotecnia | de Souza P.A.,Instituto Federal do Ceara | de Sousa A.E.D.,Federal University of Vicosa | de Oliveira Fernandes P.L.,DACS
Revista Ciencia Agronomica | Year: 2010

The aim of this work was to evaluate the effect of carnauba wax (Primax Wax) and low-density polyethylene film "X-tend" on shelf life of 'Formosa' papaya fruits produced in Baraúna, RN. The experiment was carried out in the Postharvest Laboratory of the Universidade Federal Rural do Semi-Árido (UFERSA). A 3 x 6 factorial scheme with three replications of three fruits per plot in a completely randomized design was used. The treatments consisted of the combination of three types of atmosphere (wax, polyethylene film and control) with six storage times (0; 7; 14; 21; 28 and 35). The fruits of these treatments were stored in cold chamber at 10 ± 2 °C and RH 90 ± 5%, and analyzed in 7 days intervals. The evaluated traits were: external appearance, weight loss, pulp firmness, soluble solids, titratable acidity and C vitamin. It was observed that polyethylene film was the most efficient coverage to keep the external quality and to reduce the weight loss of the papaya fruits. The carnauba wax in the used concentration shows good efficiency in papaya fruits conservation as compared with that polyethylene film. The shelf life of papaya fruits kept under modified atmosphere was of 35 days and for those fruits kept at ambient condition was of 28 days. Source


Rodrigues J.O.,Federal University of Ceara | De Andrade E.M.,Federal University of Ceara | Palacio H.A.Q.,Instituto Federal do Ceara | Mendonca L.A.R.,Federal University of Ceara | Dos Santos J.C.N.,Federal University of Ceara
Revista Ciencia Agronomica | Year: 2013

The aim of this study was to evaluate and compare the sedimentological behavior in two small rural watersheds in the semiarid Northeast of Brazil, examining the influence of human activity on the sediment yields. The studied area is sited in the Alto Jaguaribe basin, more precisely in the Iguatu County, Ceará State. The experimental area was composed of two small watersheds denominated B1 and B2. In watershed B1 a treatment (thinning) was applied, eliminating the plant species with diameters lower than 10 cm. The results showed that the Caatinga clearing practice did have an influence in changing the sediment yield during the first events. It was also found that the magnitude of previous events contributed to an increase in the sediment yields by the subsequent events as a consequence of the sediment deposit in the drainage network. The accumulated sediment yields reached at the end of the 2009 rainfall season values of 1.45 and 1.39 tons ha-1 year-1 for B1 and B2, respectively, with no significant difference at 5%. It was concluded that, even when the effect of treatment on the sediment yields at the beginning of the rainy season is measured, the total sediment yields was not changed by the adoption of clearing. Therefore, it is a management system that can be employed in the land use at semiarid regions. Source

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