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3.
Soft Matter ; 18(30): 5699-5705, 2022 Aug 03.
Article in English | MEDLINE | ID: mdl-35876272

ABSTRACT

We propose a model, based on active Brownian particles, for the dynamics of cells confined in a two-state micropattern, composed of two rectangular boxes connected by a bridge, and investigate the transition statistics. A transition between boxes occurs when the active particle crosses the center of the bridge, and the time between subsequent transitions is the dwell time. By assuming that the rotational diffusion time τ is a function of the position, some experimental observations are qualitatively recovered as, for example, the shape of the survival function. τ controls the transition from a ballistic regime at short time scales to a diffusive regime at long time scales, with an effective diffusion coefficient proportional to τ. For small values of τ, the dwell time is determined by the characteristic diffusion timescale which is constant for very low values of τ, when the rotational diffusion is much faster than the translational one and decays with τ for intermediate values of τ. For large values of τ, the interaction with the walls dominates and the particle stays mostly at the corners of the boxes increasing the dwell time. We find that there is an optimal τ for which the dwell time is minimal and its value can be tuned by changing the geometry of the pattern.

6.
Braz. j. biol ; 77(2): 356-360, Apr.-June 2017.
Article in English | LILACS | ID: biblio-888746

ABSTRACT

Abstract The Thamnophilidae are one of the most speciose Neotropical bird families, yet aspects of their natural history remain poorly documented. Here we provide information on breeding phenology, the length of incubation and nestling periods, parental care, and nesting success of the Star-throated Antwren, Rhopias gularis, an Atlantic Forest endemic. The data are discussed in light of life history theories. We found 27 active nests during two breeding seasons (2013/2014 and 2014/2015) at Carlos Botelho State Park in southeastern Brazil. Nesting activities were observed from September to January. Incubation and nestling periods lasted 16.8 ± 0.6 and 11.0 ± 0.86 days, respectively, as with most other antbirds. Males and females shared equally in incubation and nestling provisioning. The small clutch size of two eggs is that most commonly found in tropical birds and is hypothesized to have evolved due to increased nest predation rates. However, our data was not consistent with this hypothesis as the nest survival probability was high (57%). This is one of only a handful of studies that provide comprehensive information on the breeding biology of a Thamnophilid species in undisturbed habitat.


Resumo A Família Thamnophilidae compreende as diversas espécies de chocas e papa-formigas e compõem um dos maiores grupos de aves neotropicais. Apesar do elevado número de espécies, aspectos da história natural permanecem pouco documentados. No presente estudo são fornecidas informações sobre fenologia reprodutiva, duração dos períodos de incubação e permanência dos filhotes no ninho, cuidado parental e sucesso reprodutivo da choquinha-de-garganta-pintada, Rhopias gularis, endêmica da Mata Atlântica, enfocando teorias de história de vida. Foram encontrados 27 ninhos ativos durante duas temporadas reprodutivas (2013/2014 e 2014/2015) no Parque Estadual Carlos Botelho, no sudeste do Brasil. Atividades de nidificação foram observadas de setembro a janeiro. Períodos de incubação e permanência dos filhotes nos ninhos duraram 16.8 ± 0.6 e 11.0 ± 0.86 dias, respectivamente, sendo similares aos de outras chocas e papa-formigas. Machos e fêmeas dividiram as funções de incubação e alimentação dos ninhegos em taxas similares. As ninhadas de dois ovos seguem o padrão mais comum para Passseriformes tropicais, mas os dados apresentados não se mostraram consistentes com a hipótese de que a evolução de ninhadas menores está relacionada às altas taxa de predação de ninhos nesta região, uma vez que foi observada alta probabilidade de sobrevivência (57%). O presente estudo é um dos poucos a proporcionar informações abrangentes sobre a biologia reprodutiva de um Thamnophilidae em uma área preservada.


Subject(s)
Humans , Male , Female , Reproduction , Songbirds/physiology , Nesting Behavior , Brazil
7.
Braz J Biol ; 77(2): 356-360, 2017.
Article in English | MEDLINE | ID: mdl-27579975

ABSTRACT

The Thamnophilidae are one of the most speciose Neotropical bird families, yet aspects of their natural history remain poorly documented. Here we provide information on breeding phenology, the length of incubation and nestling periods, parental care, and nesting success of the Star-throated Antwren, Rhopias gularis, an Atlantic Forest endemic. The data are discussed in light of life history theories. We found 27 active nests during two breeding seasons (2013/2014 and 2014/2015) at Carlos Botelho State Park in southeastern Brazil. Nesting activities were observed from September to January. Incubation and nestling periods lasted 16.8 ± 0.6 and 11.0 ± 0.86 days, respectively, as with most other antbirds. Males and females shared equally in incubation and nestling provisioning. The small clutch size of two eggs is that most commonly found in tropical birds and is hypothesized to have evolved due to increased nest predation rates. However, our data was not consistent with this hypothesis as the nest survival probability was high (57%). This is one of only a handful of studies that provide comprehensive information on the breeding biology of a Thamnophilid species in undisturbed habitat.


Subject(s)
Nesting Behavior , Reproduction , Songbirds/physiology , Animals , Brazil , Female , Male
8.
Genet Mol Res ; 13(4): 9867-73, 2014 Nov 27.
Article in English | MEDLINE | ID: mdl-25501196

ABSTRACT

Cracids are medium to large frugivorous birds that are endemic to the Neotropics. Because of deforestation and overhunting, many species are threatened. The conservation of several species has relied on captive breeding and reintroduction in the wild, but captive populations may be inbred. Microsatellite tools can permit the construction of genetic pedigrees to reduce inbreeding, but only a few loci are available for this group of birds. Here, we present 10 novel polymorphic microsatellite loci and the cross-amplification of these and of 10 additional loci available in the literature in a panel of 5 cracid species, including 3 species with high conservation concern. We provide the first polymorphic loci for the jacutinga, Aburria jacutinga (N = 8), and red-billed curassow, Crax blumenbachii (N = 9), and additional loci for bare-faced curassow, C. fasciolata (N = 8), Alagoas curassow, Pauxi mitu (N = 5), and razor-billed curassow, P. tuberosa (N = 5). The average number of alleles was 2.9 for A. jacutinga, 2.7 for C. blumenbachii, 3.5 for C. fasciolata, 2.6 for P. mitu, and 5.7 for P. tuberosa. The mean expected heterozygosities were 0.42, 0.40, 0.48, 0.37, and 0.59, respectively. The average probabilities that the set of loci would not exclude a pair of parents of an arbitrary offspring were 2.9% in A. jacutinga, 1% in C. blumenbachii, 0.5% in C. fasciolata, 0.4% in P. mitu, and 0.002% in P. tuberosa suggesting that these loci may be adequate for parentage analysis and to implement ex situ genetic management plans.


Subject(s)
Conservation of Natural Resources , Galliformes/genetics , Microsatellite Repeats/genetics , Alleles , Animals , Genetic Loci , Heterozygote
9.
Braz. j. biol ; 67(4,supl): 867-872, Dec. 2007. ilus, tab
Article in English | LILACS | ID: lil-474225

ABSTRACT

Randomly amplified polymorphic DNA (RAPD) markers were used to analyze genetic differentiation among three populations of the endemic Black-cheeked Gnateater (Conopophaga melanops melanops) within a larger pristine reminiscent of the Brazilian Atlantic Forest. Analyses of molecular variance (AMOVA) (phiST = 0.13149, P < 0.0001) and the nonparametric test for homogeneity of the molecular variance (HOMOVA) (B = 0.32337; P = 0.0019) showed a statistically significant genetic divergence among the three Black-cheeked Gnateater populations in a continuous transect of 250 km. Some hypothetic explanations for these results are the sedentary nature of the species and the historical isolation of the populations in refuges during the Pleistocene. The present results suggest that the local populations were naturally differentiated along the entire original range before the recent process of massive deforestation.


Marcadores polimórficos de DNA amplificados ao acaso (RAPD) foram utilizados para analisar a diferenciação genética entre três populações do endêmico cuspidor-de-máscara preta (Conopophaga melanops melanops) de um amplo remanescente preservado da floresta Atlântica brasileira. Análises de Variância Molecular (AMOVA) (fiST = 0,13149, P < 0,0001) e o teste não paramétrico para a homogeneidade da variância molecular (HOMOVA) (B = 0,32337; P = 0,0019) comprovaram uma divergência genética significativa entre as três populações em um transecto contínuo de 250 km. Algumas explicações hipotéticas para estes resultados são a natureza sedentária da espécie e o isolamento histórico das populações em refúgios durante o Pleistoceno. Os presentes resultados sugerem que as populações locais foram diferenciadas naturalmente ao longo da distribuição original antes do recente processo de intenso desmatamento.


Subject(s)
Animals , Genetic Variation , Passeriformes/genetics , Trees , Analysis of Variance , Brazil , Genetic Markers/genetics , Polymerase Chain Reaction , Passeriformes/classification , Random Amplified Polymorphic DNA Technique
10.
Braz. j. biol ; 67(4): 627-634, Nov. 2007. tab
Article in English | LILACS | ID: lil-474185

ABSTRACT

Several plant characteristics, such as fruit production, nutrient reward, secondary compounds, and fruit color display, affect fruit choice by birds. On the other hand, several bird attributes affect their efficiency as dispersers. Here we investigate the ornithochoric seed dispersal of Pera glabrata Schott (Euphorbiaceae) in a cerrado fragment in southeastern Brazil. A set of bird attributes, such as frequency of visits, number of diaspores eaten, time spent foraging, methods of taking and handling the diaspores and agonistic interactions were analyzed in order to infer about the potential of each species to act as a seed disperser. Birds were the unique seed dispersers of these oil-rich diaspores. We observed 414 bird visits during 60 hours of focal observations in five trees from December 1999 to January 2000. Twenty bird species from seven families ate the diaspores of P. glabrata, but only 14 species were considered potential seed dispersers because they swallowed the diaspores, increasing the probabilities for the seeds to be defecated and/or regurgitated away from the parent trees. The main potential seed dispersers were: Turdus leucomelas (Muscicapidae), Dacnis cayana (Emberizidae), Colaptes melanochloros (Picidae) and Elaenia spp. (Tyrannidae). We did not find any significant seasonal change in the number of visits on the fruiting trees throughout the day. We also did not find any relation between the number of visits per tree and fruit production. The most effective seed dispersers of P. glabrata were generalist birds, which have a high visiting rate, high fruit consumption rate, and spend short periods on the plants. The large number of species recorded as potential seed dispersers of P. glabrata, being most of them very abundant even in Brazilian disturbed areas, may guarantee seed dispersal of this plant in small fragments and regenerating areas.


As diferentes espécies de plantas apresentam características que podem influenciar na atração das aves frugívoras, como a quantidade de frutos produzidos, o valor nutritivo dos frutos, a presença de compostos secundários e o display de cores. Por outro lado, diversos estudos têm demonstrado que as espécies de aves que consomem frutos não apresentam a mesma eficiência como dispersores das sementes. Embora estudos sobre a frugivoria e dispersão de sementes sejam de grande importância para a realização de planos de manejo e recuperação de áreas degradadas, pouco tem sido pesquisado sobre o assunto no cerrado brasileiro. Neste trabalho são apresentados aspectos da frugivoria e dispersão ornitocórica das sementes de Pera glabrata Schott (Euphorbiaceae) num fragmento de cerrado do sudeste do Brasil. Atributos das aves, como freqüência de visitas, número de diásporos consumidos, tempo de permanência sobre as plantas, métodos de captura e mandibulação dos diásporos, bem como interações antagônicas, foram analisados para se inferir sobre o potencial de cada espécie para atuar como dispersora das sementes. As aves foram os únicos potenciais dispersores dos diásporos. Em 60 horas de observações focais, realizadas entre dezembro de 1999 e janeiro de 2000, foram registradas 414 visitas de 20 espécies de aves pertencentes a sete famílias. No entanto, apenas 14 destas espécies foram consideradas como potenciais dispersores. Os principais potenciais dispersores foram Turdus -leucomelas (Muscicapidae), Dacnis cayana (Emberizidae), Colaptes melanochloros (Picidae) e Elaenia spp. (Tyrannidae). O número de visitas não diferiu significativamente entre os diferentes intervalos de hora do dia. Não foi encontrada correlação significativa entre o número de visitas e o número de frutos presentes em cada árvore. As aves generalistas foram as principais potenciais dispersoras de P. glabrata, tendo apresentado altas taxas de visitação, alto consumo de diásporos,...


Subject(s)
Animals , Birds/physiology , Euphorbiaceae , Feeding Behavior/physiology , Seeds , Trees , Brazil
11.
Braz J Biol ; 67(4 Suppl): 867-72, 2007 12.
Article in English | MEDLINE | ID: mdl-18278353

ABSTRACT

Randomly amplified polymorphic DNA (RAPD) markers were used to analyze genetic differentiation among three populations of the endemic Black-cheeked Gnateater (Conopophaga melanops melanops) within a larger pristine reminiscent of the Brazilian Atlantic Forest. Analyses of molecular variance (AMOVA) (phiST=0.13149, P<0.0001) and the nonparametric test for homogeneity of the molecular variance (HOMOVA) (B=0.32337; P=0.0019) showed a statistically significant genetic divergence among the three Black-cheeked Gnateater populations in a continuous transect of 250 km. Some hypothetic explanations for these results are the sedentary nature of the species and the historical isolation of the populations in refuges during the Pleistocene. The present results suggest that the local populations were naturally differentiated along the entire original range before the recent process of massive deforestation.


Subject(s)
Genetic Variation/genetics , Passeriformes/genetics , Trees , Analysis of Variance , Animals , Brazil , Genetic Markers/genetics , Passeriformes/classification , Polymerase Chain Reaction , Random Amplified Polymorphic DNA Technique
12.
Braz J Biol ; 67(4): 627-34, 2007 Nov.
Article in English | MEDLINE | ID: mdl-18278313

ABSTRACT

Several plant characteristics, such as fruit production, nutrient reward, secondary compounds, and fruit color display, affect fruit choice by birds. On the other hand, several bird attributes affect their efficiency as dispersers. Here we investigate the ornithochoric seed dispersal of Pera glabrata Schott (Euphorbiaceae) in a cerrado fragment in southeastern Brazil. A set of bird attributes, such as frequency of visits, number of diaspores eaten, time spent foraging, methods of taking and handling the diaspores and agonistic interactions were analyzed in order to infer about the potential of each species to act as a seed disperser. Birds were the unique seed dispersers of these oil-rich diaspores. We observed 414 bird visits during 60 hours of focal observations in five trees from December 1999 to January 2000. Twenty bird species from seven families ate the diaspores of P. glabrata, but only 14 species were considered potential seed dispersers because they swallowed the diaspores, increasing the probabilities for the seeds to be defecated and/or regurgitated away from the parent trees. The main potential seed dispersers were: Turdus leucomelas (Muscicapidae), Dacnis cayana (Emberizidae), Colaptes melanochloros (Picidae) and Elaenia spp. (Tyrannidae). We did not find any significant seasonal change in the number of visits on the fruiting trees throughout the day. We also did not find any relation between the number of visits per tree and fruit production. The most effective seed dispersers of P. glabrata were generalist birds, which have a high visiting rate, high fruit consumption rate, and spend short periods on the plants. The large number of species recorded as potential seed dispersers of P. glabrata, being most of them very abundant even in Brazilian disturbed areas, may guarantee seed dispersal of this plant in small fragments and regenerating areas.


Subject(s)
Birds/physiology , Euphorbiaceae , Feeding Behavior/physiology , Seeds , Trees , Animals , Brazil
13.
Acta fisiátrica ; 14(1): 41-48, mar. 2007.
Article in English, Portuguese | LILACS | ID: lil-536578

ABSTRACT

Os pontos-gatilho (PG) miofasciais são encontrados em muitas lesões cervicais com hiperextensão/hiperflexão, discopatias e lesões/desordens por esforço repetitivo. Desde o extremo da simulação, ao frustrante dilema na investigação objetiva da dor crônica, uma das indicações básicas e melhores da comprovação por imagem infravermelha (IR) é a de documentar afecções de tecidos moles, particularmente nos casos em que não são demonstradas por exames radiológicos, eletroneuromiográficos ou laboratoriais. Os autores revisaram a literatura sobre imagem IR na documentação da síndrome dolorosa miofascial. O exame por IR é complemento essencial do diagnóstico clínico mostrando objetivamente PG na forma de pontos aquecidos hiperradiantes. Estas áreas hiperradiantes, correspondem a PG dolorosos anotados no exame clínico. Estes são corroborados pela sensibilidade local e confirmação da dor pelos pacientes. As áreas dolorosas referidas se apresentam termicamente assimétricas com o lado oposto. Os PG latentes, não objetivamente queixados pelos pacientes durante o exame IR, também são descritos sob a forma de pontos hiperradiantes. A presença destes PG latentes pode ser confirmada pela algometria de pressão nestas áreas. Após infiltração/agulhamento há alteração do perfil térmico cutâneo demonstrando resposta neurovegetativa simpática imediata. As alterações de imagem IR se constituem, assim, em importante recurso objetivo na demonstração de PG miofasciais, correlatos com as queixas objetivas do paciente. A documentação dos PG por imagem IR é útil no direcionamento para causa da dor, orientação do tratamento adequado, assim como avaliação de sua resposta.


The myofascial trigger points (TP) are involved as much pathologies of hyperextension/hyperflexion cervical injuries, disc injuries, and overuse injuries. From the extreme of malingerer to the frustrating dilemma of intractable chronic myofascial pain, the documentation of this alteration is in the majority of the cases subjective and a dilemma. One of the basic indications and clinical uses of infrared (IR) imaging is documentation of soft tissue pathology, particularly in conditions which cannot be demonstrated on radiologic tests, electroneuromyography or laboratory workup. The authors review the literature regarding IR imaging in the documentation of myofascial pain syndrome. The IR imaging is a diagnostic test which objectively documents TP in the form of hyperradiant hot spots. These hyperradiant spots corresponding to areas of pain usually represent active TP in clinical examination. They can be corroborated by local tenderness in the region, thus confirming the patient?s complaint. The areas of pain are presented as thermal asymmetry between corresponding areas of opposite sides of the body. Latent TP, not subject to patient complaints at the time of IR imaging examination, are detected in the form of hyperradiant spots. The presence of these latent TP can be documented by abnormal pressure threshold measurement in these areas. There was an alteration of the skin thermal profile after TP local anesthesia/dry needling demonstrating an immediate neurovegetative sympathetic response. The IR imaging findings represent an objective mean to document TP, thus corroborating with the subjective patient?s complaints. The documentation of TP by IR imaging is important to introduce the most adequate treatment directed the pain cause as well as to evaluate its response.


Subject(s)
Humans , Thermography/instrumentation , Chronic Pain/etiology , Myofascial Pain Syndromes/diagnostic imaging
14.
Hereditas ; 134(3): 225-8, 2001.
Article in English | MEDLINE | ID: mdl-11833285

ABSTRACT

Chromosomes obtained from feather tissues of 14 species of Brazilian Psittacidae were analyzed by Giemsa conventional staining and the karyotypes of Ara chloroptera, Propyrrhura maracana and Nandayus nenday are presented for the first time. The remaining species showed no chromosome differences when compared with previous literature data. Two basic karyotype patterns were observed. A karyotype pattern is mostly characterized by biarmed macrochromosomes, while in the other one most macrochromosomes are telocentrics.


Subject(s)
Chromosomes , Psittaciformes/classification , Psittaciformes/genetics , Animals , Brazil , Chromosomes/ultrastructure , Cytogenetic Analysis , Evolution, Molecular , Feathers , Female , Karyotyping , Male , Metaphase , Mitosis , Sex Chromosomes/ultrastructure
15.
Rev. bras. oftalmol ; 50(3): 9-12, jun. 1991.
Article in Portuguese | LILACS | ID: lil-99985

ABSTRACT

Os AA. sugerem a dosagem de anticorpos HIV em humor vitreo como método de rastreamento de individuos portadores de SIDA, principalmente nos casos de transplante de córnea, onde o próprio banco de olhos faria os exames, e naqueles casos onde a retirada do sangue pós-morte é difícil. Realizaram estudos em 10 olhos de pacientes que morreram por complicaçöes relativas à SIDA, sendo a positividade dos exames de 100 p/cento. Para eliminar os falsos positivos, realizaram estudo em grupo de 90 olhos de pacientes que morreram em situaçöes näo decorrentes da SIDA, onde todos os resultados foram negativos, näo havendo discrepâncias entre sangue e vítreo. Descrevem técnica utilizando trocarte especial que permite realizar o exame sem contaminaçäo do sangue. Chegam a conclusäo que a dosagem de anticorpos em vítreo é uma opçäo a ser considerada, devido a facilidade de sua obtençäo e resultados satisfatórios, como exame após óbito


Subject(s)
Humans , Acquired Immunodeficiency Syndrome , Cornea/transplantation , HIV Antibodies , Brazil
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