928 resultados para radius of starlikeness


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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The arrival of migratory shorebirds on beaches in urban communities in developing countries is a current challenge for the protection of these migrant birds. Nearctic-Neotropical migrants rely on roosting and feeding sites during their stopover on wintering sites in the Southern Hemisphere to acquire sufficient energy to complete their migratory cycles. On the other hand, cities in the Southern Hemisphere are growing rapidly, which results in increasing competition for space between humans and birds, such as for use in beach habitats. In the present study, I analyze the probability for occurrence for Nearctic-Neotropical migratory birds relative to the number of people in southeastern Brazil, the most populated region of South America. The frequency of occurrence of migrants, their distance of tolerance to people and the number of people were recorded in sample areas (circle plots with 20 m radius) on a 9 km stretch of urban beaches from November to February from 2009 to 2013. The probability of occurrence of Nearctic birds decreased as the number of people increased. When the number of people exceeded 20, the probability of occurrence of birds was almost zero. Furthermore, more than 95 % of birds moved off when people were within 16 m of reach. These results are discussed in the context of conservation actions since no management plan has been developed for migrant shorebirds that use urban beaches as stopover or wintering sites in developing countries.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Objectives: To evaluate bone healing in an experimental radial ostectomy in dogs treated with autologous platelet-rich plasma (PRP), through histological, densitometric, radiographic studies, as well as expression of growth factors in the ostectomy gap. Methods: Twenty-one dogs were randomly divided into either a control or a PRP group. All underwent unilateral ostectomy of the radius to generate a gap of 2.0 mm, that was stabilized with external skeletal fixation. The ostectomy gap was either filled with PRP or left empty as a control. The radiographic and densitometric studies were performed after surgery, then at intervals until 60 days during the post-surgery period. Histological and immunohistochemical evaluations were performed at seven or 60 days post-surgery. Analyses were performed using a statistical analysis system, and the level of significance was set at p <0.05. Results: The median radiographic healing score in the PRP group increased significantly between day 0 and day 60. Furthermore, at 60 days, the median healing score and the proportion of healed ostectomies in the control group (score 1; 1/6 healed) and the PRP group (score 5; 4/5 healed) were significantly different. There were differences between groups in radiographic and densitometric values at days 45 and 60. The histological evaluation showed advanced bone healing at 60 days in the PRP group and signs of delayed union in the control group. Clinical relevance: Platelet-rich plasma can be used as an adjuvant therapy because it may promote better bone healing of a radial ostectomy treated with external skeletal fixation in dogs.

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Background: Most of the primary pulmonary tumors in dogs are malignant and from epithelial origin, being bronchioalveolar tumors more prevalent. Adenocarcinoma of clear cells, however, is a very rare pulmonary tumor and its origin is still unknown. It is related to several clinical abnormalities, including hypertrophic osteopathy, an unusual paraneoplastic syndrome characterized by a periosteal reaction along the shaft of long bones. Because of the unusual presentation of the pulmonary adenocarcinoma, the aim of this study was to describe the radiographic, histopathological, and immunohistochemical fi ndings of a dog affl icted with hypertrophic osteopathy secondary to an undifferentiated pulmonary adenocarcinoma of clear cells. Case: A 12-year-old, 45 kg, not castrated male Great Dane dog was presented with painful swelling of all four limbs and moderate respiratory distress. Radiographic examination and computed tomography of the limbs showed palisade-like periosteal bone proliferation involving radius, ulna, femur, patella, tibia, fi bula, tarsus, metacarpal, metatarsal and digits, suggesting hypertrophic osteopathy. Radiographic examination and computed tomography of the lungs also showed a round mass well delimited localized in the right diaphragmatic lobe. A lobectomy of the right diaphragmatic lobe and partial lobectomy of accessory lobe were performed. A poorly differentiated clear squamous cell carcinoma was diagnosed by histological examination. An immune-panel of CK5/CK6, CK7, p63 and TTF-1 was used for immunophenotyping. Immunostaining was weakly positive for CK5/CK6 and negative to all others. Therefore, the diagnosis was poorly differentiated clear cell adenocarcinoma. The dog showed improvement in clinical signs seven days after surgery. One month postoperatively, radiographic examination of the limbs showed less intense periosteal reaction and initiation of bone remodeling. Discussion: Primary pulmonary tumors are considered very infrequent in small animals, but its true incidence rate is dif- fi cult to establish in animal populations. The histological origin of the tumor in the present case, as verifi ed in the literature, is not well established by histological analysis. In these situations, the immunohistochemistry panel may be useful. The modifi cation of the diagnosis between histological analysis and by immunohistochemistry, among other factors, might be due to transdifferentiation from one phenotype to another at various stages in the neoplastic process. The clear cell appearance observed in this case may be verifi ed in all types of carcinoma due to intracellular accumulation of glycogen, most of which is dissolved during the preparation of paraffi n sections. This uncommon neoplasm apparently did not infl uence the radiographic or tomographic fi ndings of the hypertrophic osteopathy in the present case. The frequency of metastases depends on the histological type of the tumor, being common in the pulmonary adenocarcinoma and usually to tracheobronchial lymph nodes and pulmonary parenchyma. Although in this case the imaging studies did not show metastases to other pulmonary lobes, the histological exams showed metastatic lesions that may be associated to the dog’s death after the surgery.

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Two roadside surveys were conducted for dwarf mistletoes parasitizing lodgepole pine and Douglas-fir on the Sawtooth National Forest, Idaho. One survey used variable-radius plots located less than 150 m from roads. The 2nd survey used variable-radius plots established at 200-m intervals along 1600-m transects run perpendicular to the same roads. Estimates of the incidence (percentage of trees infected and percentage of plots infested) and severity (average dwarf mistletoe rating) for both lodgepole pine and Douglas-fir dwarf mistletoes were not significantly different for the 2 survey methods. These findings are further evidence that roadside-plot surveys and transect-plot surveys conducted away from roads provide similar estimates of the incidence of dwarf mistletoes for large forested areas.

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Many bird species are attracted to landfills which take domestic or putrescible waste. These sites provide a reliable, rich source of food which can attract large concentrations of birds. The birds may cause conflicts with human interest with respect to noise, birds carrying litter off site, possible transmission of pathogens in bird droppings and the potential for birdstrikes. In the UK there is an 8 mile safeguarding radius around an airfield, within which any planning applications must pass scrutiny from regulatory bodies to show they will not attract birds into the area and increase the birdstrike risk. Peckfield Landfill site near Leeds, West Yorkshire was chosen for a trial of a netting system designed to exclude birds from domestic waste landfills. The site was assessed for bird numbers before the trial, during the netting trial and after the net had been removed. A ScanCord net was installed for 6 weeks, during which time all household waste was tipped inside the net. Gull numbers decreased on the site from a mean of 1074 per hourly count to 29 per hourly count after two days. The gull numbers increased again after the net had been removed. Bird concentrations in the surroundings were also monitored to assess the effect of the net. Bird numbers in the immediate vicinity of the landfill site were higher than those further away. When the net was installed, the bird concentrations adjacent to the landfill site decreased. Corvids were not affected by the net as they fed on covered waste which was available outside the net throughout the trial. This shows that bird problems on a landfill site are complex, requiring a comprehensive policy of bird control. A supporting bird scaring system and clear operating policy for sites near to airports would be required.

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Polyvinylpyrollidone (PVP)-capped platinum nanoparticles (NPs) are found to change shape from spherical to flat when deposited on mesoporous silica substrates (SBA-15). Transmission electron microscopy (TEM), small-angle X-ray scattering (SAXS), and extended X-ray absorption fine structure (EXAFS) analyses are used in these studies. The SAXS results indicate that, after deposition, the 2 nm NPs have an average gyration radius 22% larger than in solution, while the EXAFS measurements indicate a decrease in first neighbor co-ordination number from 9.3 to 7.4. The deformation of these small capped NPs is attributed to interactions with the surface of the SBA-15 support, as evidenced by X-ray absorption near-edge structure (XANES).

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We report on the strong temperature-dependent thermal expansion, alpha(D), in CdS quantum dots (QDs) embedded in a glass template. We have performed a systematic study by using the temperature-dependent first-order Raman spectra, in CdS bulk and in dot samples, in order to assess the size dependence of alpha(D), and where the role of the compressive strain provoked by the glass host matrix on the dot response is discussed. We report the Gruneisen mode parameters and the anharmonic coupling constants for small CdS dots with mean radius R similar to 2.0 nm. We found that gamma parameters change, with respect to the bulk CdS, in a range between 20 and 50%, while the anharmonicity contribution from two-phonon decay channel becomes the most important process to the temperature-shift properties.

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In the present work we revisit the size data of CdS microcrystals previously collected in the glassy matrix of Germanium oxide. The CdS clusters analyzed using electron microscopy images have shown a wurtzite structure. The mean average radius, dispersion and volume evaluated from the histograms showed good agreement for t(1/3), t(2/3) and t laws, respectively. We observed that the amount of microcrystals remains constant throughout the heat treatment process, as well as that the radii distribution has a lower limit and increases with heat treatment. The distribution of radii follows a distribution similar to the Lifshitz-Slyozov-Wagner distribution limited in the origin. Discussions led to the conclusion that the growth of CdS is a process that occurs after the fluctuating nucleation and coalescence phases. We then analyze the growth process, assuming that the evaporation is overcome by the precipitation rate, stabilizing all clusters with respect to dissolution back into the matrix. The problem was simplified neglecting anisotropy and the assuming a spherical shape for clusters and particles. The low interface tension was described in terms of an empirical potential barrier in the surface of the cluster. The growth dynamics developed considering that the number of clusters remains constant, and that the minimum size of these clusters grow with time, as the first order approximation showed a good agreement with the flaw. (C) 2012 Elsevier B.V. All rights reserved.

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Aims. Several embedded clusters are found in the Galaxy. Depending on the formation scenario, most of them can evolve to unbounded groups that are dissolved within 10 Myr to 20 Myr. A systematic study of young stellar clusters that show distinct characteristics provides interesting information on the evolutionary phases during the pre-main sequence. To identify and to understand these phases we performed a comparative study of 21 young stellar clusters. Methods. Near-infrared data from 2MASS were used to determine the structural and fundamental parameters based on surface stellar density maps, radial density profile, and colour-magnitude diagrams. The cluster members were selected according to their membership probability, which is based on the statistical comparison with the cluster proper motion. Additional members were selected on the basis of a decontamination procedure that was adopted to distinguish field stars found in the direction of the cluster area. Results. We obtained age and mass distributions by comparing pre-main sequence models with the position of cluster members in the colour-magnitude diagram. The mean age of our sample is similar to 5 Myr, where 57% of the objects is found in the 4-10 Myr range of age, while 43% is <4 Myr old. Their low E(B - V) indicate that the members are not suffering high extinction (AV <1 mag), which means they are more likely young stellar groups than embedded clusters. Relations between structural and fundamental parameters were used to verify differences and similarities that could be found among the clusters. The parameters of most of the objects show the same trends or correlations. Comparisons with other young clusters show similar relations among mass, radius, and density. Our sample tends to have larger radius and lower volumetric density than embedded clusters. These differences are compatible with the mean age of our sample, which we consider intermediate between the embedded and the exposed phases of the stellar clusters evolution.