1,289 research outputs found

    Cytometric evaluation of abdominal subcutaneous adipocytes after percutaneous CO2 infiltration

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    OBJETIVO: Avaliar os efeitos da infiltração de dióxido de carbono em adipócitos presentes na parede abdominal. MÉTODOS: Quinze voluntárias foram submetidas a sessões de infusão de CO2 durante três semanas consecutivas (duas sessões por semana com intervalos de dois a três dias entre cada sessão). O volume de gás carbônico infundido por sessão, em pontos previamente demarcados, foi sempre calculado com base na superfície da área a ser tratada, com volume infundido fixo de 250 mL/100cm² de superfície tratada. Os pontos de infiltração foram demarcados respeitando-se o limite eqüidistante 2cm entre eles. Em cada ponto se injetou 10mL, por sessão, com fluxo de 80mL/min. Foram colhidos fragmentos de tecido celular subcutâneo da parede abdominal anterior antes e após o tratamento. O número e as alterações histomorfológicas dos adipócitos (diâmetro médio, perímetro, comprimento, largura e número de adipócitos por campos de observação) foram mensurados por citometria computadorizada. Os resultados foram analisados com o teste t de Student pareado, adotando-se nível de significância de 5% (p<0,05). RESULTADOS: Encontrou-se redução significativa no número de adipócitos da parede abdominal e na área, diâmetro, perímetro, comprimento e largura após o uso da hipercapnia (p=0,0001). CONCLUSÃO: A infiltração percutânea de CO2 reduz a população e modifica a morfologia dos adipócitos presentes na parede abdominal anterior.OBJECTIVE: To evaluate the effects of carbon dioxide infusion to abdominal wall adipocytes. METHODS: Fifteen volunteers were subjected to sessions of CO2 infusion for three consecutive weeks (two sessions per week with intervals of two to three days between each). The volume of carbon dioxide infused per session, at points previously marked, was always calculated on the basis of surface area to be treated, with a fixed infused volume of 250 ml/100cm² of treated surface. The infiltration points were marked respecting the limit of 2cm equidistant between them. At each point 10 ml was injected per session, with a flow of 80ml/min. Fragments were collected from subcutaneous tissue of the anterior abdominal wall before and after treatment. The number and histomorphological changes of adipocytes (mean diameter, perimeter, length, width and number of adipocytes per field of observation) were measured by computerized cytometry. The results were analyzed with paired Student t test, adopting a significance level of 5% (p <0.05). RESULTS: There was a significant reduction in the number of adipocytes in the abdominal wall, as well as the area, diameter, perimeter, length and width of the adipocytes, after the infusion of CO2 (p = 0.0001). CONCLUSION: The percutaneous infiltration of CO2 reduces the population of adipocytes of the anterior abdominal wall and modifies their morphology

    ¿Estamos avanzando hacía una socio-ecología? Reflexiones sobre la integración de las dimensiones "humanas" en la ecología en el sur de América

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    La complejidad y la velocidad de los actuales cambios ambientales a escala global presentan desafíos y oportunidades para la investigación, la gestión y la conservación de la biosfera (Millenium Ecosystem Assessment [MA] 2005). La magnitud de estos cambios derivó en la propuesta de llamar Antropoceno a nuestra época geológica (Crutzen 2002), ya que los seres humanos nos hemos convertido en la mayor fuerza de cambio planetario. Es evidente que los grandes factores promotores de este nuevo escenario (e.g., el calentamiento global, la urbanización y la globalización cultural y económica) afectan a los ecosistemas (Ellis et al. 2011), aunque también existe un reconocimiento creciente de que estos factores influyen sobre las sociedades humanas (MA 2005). Por lo tanto, se puede decir que los problemas categorizados tradicionalmente como “ambientales” (e.g., el cambio climático) poseen causas y consecuencias sociales (e.g., políticas energéticas para combustibles fósiles, impacto económico de la desertificación). De manera recíproca, los problemas “humanos” (e.g., planificación territorial y políticas de inmigración) están vinculados a los ecosistemas y a la biodiversidad (e.g., fragmentación del paisaje, introducción de especies no-nativas y homogeneización biótica). En el contexto del Antropoceno, se hace urgente integrar las dimensiones ecológicas y las sociales del ambiente para mejorar nuestro conocimiento y tomar decisiones más efectivas (Carpenter et al. 2009). El desafío llega a ser aun más relevante en Latinoamérica, que cubriendo sólo el 10% de la superficie del planeta alberga el 50% de la biodiversidad terrestre (Wilson 1989) y el 15% de la diversidad lingüística (Skutnabb-Kangas 2000). Es en Latinoamérica donde se han generado grandes conflictos socioambientales (Wagner 2010). Entonces, ¿Qué papel tiene la ecología como disciplina en Argentina y Chile con respecto a estas transformaciones? Sabemos que a nivel mundial y regional existen ejemplos de integración entre diversos campos académicos que abordan problemáticas “bioculturales” (Toledo & Barrera 2008) y “socioecológicas” (Domptail et al. 2013) de manera interdisciplinaria. Por estas razones, y para pensar juntos sobre esta conceptualización de lo “humano” y lo “natural” en la ecología en nuestros países, presentamos el simposio “Socio-ecología: Avanzando hacia la Integración de ‘la Dimensión Humana’ en el Estudio y Entendimiento de los Ecosistemas del Sur de Sudamérica” en la V Reunión Binacional de Ecología realizada en Chile en 2013. Las reflexiones y discusiones del simposio motivaron este artículo, que sin ser una revisión exhaustiva, intenta catalizar el debate sobre lo socioecológico en la ecología austral. Consideramos que la interdisciplinariedad es una propiedad emergente del análisis holístico de una problemática compleja (García 2006). De esta forma quisimos superar el sesgo de la hiper-especialización individual, obstáculo para reflexiones epistemológicas y prácticas del quehacer de la ecología (Graham & Dayton 2002). Al usar distintas perspectivas acerca de estas preguntas: a) ofrecemos una breve reseña de algunas bases epistemológicas de la dimensión humana en la ecología y revisamos las tendencias en las publicaciones socio-ecológicas a nivel mundial y regional, b) consideramos aspectos interdisciplinarios de la formación de los profesionales relacionados con la ecología y c) presentamos antecedentes de la ciencia ciudadana para ilustrar la integración de nuevos actores sociales en la investigación ecológica. Esperamos contribuir al debate sobre la postura actual y futura que pueda tener la ecología en nuestros países, y hacemos un llamado a convertirnos en agentes activos de la conceptualización y las aproximaciones de investigación y formación.Fil: Anderson, Christopher Brian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina. Universidad Nacional de Tierra del Fuego, Antártida e Islas del Atlántico Sur. Instituto de Ciencias Polares, Recursos Naturales y Ambiente. Departamento de Biología; ArgentinaFil: Pizarro Pinochet, Jose Cristobal. University Of Waterloo; CanadáFil: Fontana Estevez, Rodrigo Javier. Pontificia Universidad Católica de Chile; ChileFil: Sapoznikow, Alexandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Pauchard, Aníbal. Universidad de Concepción; Chile. Instituto de Ecología y Biodiversidad; ChileFil: Barbosa, Olga. Instituto de Ecología y Biodiversidad; Chile. Universidad Austral de Chile; Chile. Centro de Desarrollo Urbano Sustentable; ChileFil: Moreira Muñoz, Andrés. Pontificia Universidad Católica de Valparaíso; ChileFil: Valenzuela, Alejandro Eduardo Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Administración de Parques Nacionales; Argentina. Universidad Nacional de Tierra del Fuego, Antártida e Islas del Atlántico Sur. Instituto de Ciencias Polares, Recursos Naturales y Ambiente. Departamento de Biología; Argentin

    Delineation of management zones using mobile measurements of soil apparent electrical conductivity and multivariate geostatistical techniques

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    Site-specific management promotes the identification and management of areas within the field, which represent subfield regions with homogeneous characteristics (management zones). However, determination of subfield areas is difficult because of the complex combination of factors which could affect crop yield. One possibility to capture yield variability is the use of soil physical properties to define the management zones as they are related to plant available water. With the aim of characterizing the spatial variability of the main soil physical variables and using this information to determine potential management zones, soil samples were taken from 70 locations in a 33-ha field in Badajoz, southwestern Spain. Firstly, accurate spatial distribution maps of the soil attributes were generated by using regression kriging as the most suitable algorithm in which exhaustive secondary information on soil apparent electrical conductivity (ECa) was incorporated. ECa measurements were carried out with a Veris 3100 operating in both shallow (0–30 cm), ECs, and deep (0–90 cm), ECd,mode. Clay, coarse sand and fine sand were the soil physical properties which exhibited higher correlation with ECa (positively correlated with the finer texture component, clay, and negatively correlated with the coarser ones, coarse and fine sands), particularly with ECs. Thus, this was the secondary variable used to obtain the kriged maps. Later, principal component analysis and fuzzy cluster classification were performed to delineate management zones, resulting in two subfields to be managed separately. This number of subfields was determined using the fuzzy performance index and normalized classification entropy as the way to optimize the classification algorithm

    Boundary Modes in the Chamon Model

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    We study the fracton phase described by the Chamon model in a manifold with a boundary. The new processes and excitations emerging at the boundary can be understood by means of a diagrammatic framework. From a continuum perspective, the boundary theory is described by a set of scalar fields in similarity with the standard KK-matrix Chern-Simons theory. The continuum theory recovers the gapped boundaries of the lattice model once we include sufficiently strong interactions that break charge conservation. The analysis of the perturbative relevance of the leading interactions reveals a regime in which the Chamon model can have a stable gapless fractonic phase at its boundary.Comment: 29 pages, 6 figures, extended discussions, references added, minor correction

    Quasinormal modes and stability of accelerating Reissner-Norsdtröm AdS black holes

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    We investigate the numerical stability of accelerating AdS black holes against linear scalar perturbations. In particular, we study the evolution of a probe non-minimally coupled scalar field on Schwarzschild and Reissner-Nordström AdS black holes with small accelerations by computing the quasinormal modes of the perturbation spectrum. We decompose the scalar field Klein-Gordon equation and study the eigenvalue problem for its angular and radial-temporal parts using different numerical methods. The angular part is written in terms of the Heun solution and expanded through the Frobenius method which turns out to give eigenvalues qualitatively similar to the ones obtained through the spherical harmonics representation. The radial-temporal evolution renders a stable field profile which is decomposed in terms of damped and purely imaginary oscillations of the quasinormal modes. We calculate the respective frequencies for different spacetime parameters showing the existence of a fine-structure in the modes, for both real and imaginary parts, which is not present in the non-accelerating AdS black holes. Our results indicate that the Schwarzschild and Reissner-Nordström AdS black holes with small accelerations are stable against linear scalar perturbations

    Markedly Divergent Tree Assemblage Responses to Tropical Forest Loss and Fragmentation across a Strong Seasonality Gradient

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    We examine the effects of forest fragmentation on the structure and composition of tree assemblages within three seasonal and aseasonal forest types of southern Brazil, including evergreen, Araucaria, and deciduous forests. We sampled three southernmost Atlantic Forest landscapes, including the largest continuous forest protected areas within each forest type. Tree assemblages in each forest type were sampled within 10 plots of 0.1 ha in both continuous forests and 10 adjacent forest fragments. All trees within each plot were assigned to trait categories describing their regeneration strategy, vertical stratification, seed-dispersal mode, seed size, and wood density. We detected differences among both forest types and landscape contexts in terms of overall tree species richness, and the density and species richness of different functional groups in terms of regeneration strategy, seed dispersal mode and woody density. Overall, evergreen forest fragments exhibited the largest deviations from continuous forest plots in assemblage structure. Evergreen, Araucaria and deciduous forests diverge in the functional composition of tree floras, particularly in relation to regeneration strategy and stress tolerance. By supporting a more diversified light-demanding and stress-tolerant flora with reduced richness and abundance of shade-tolerant, old-growth species, both deciduous and Araucaria forest tree assemblages are more intrinsically resilient to contemporary human-disturbances, including fragmentation-induced edge effects, in terms of species erosion and functional shifts. We suggest that these intrinsic differences in the direction and magnitude of responses to changes in landscape structure between forest types should guide a wide range of conservation strategies in restoring fragmented tropical forest landscapes worldwide

    Atributos ecológicos de anuros neotropicais: o que podem predizer?

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    O risco de extinção e o declínio populacional de muitas espécies animais na região neotropical estão fortemente relacionados aos processos antrópicos, como a conversão ambiental, mas também aos fatores intrínsecos aos próprios indivíduos, como os atributos. Os anuros correspondem ao grupo vertebrado mais ameaçado atualmente, sofrendo com sérios declínios populacionais. Este trabalho buscou avaliar quais os atributos dos anfíbios neotropicais podem predizer: i) as categorias de ameaça e tendências populacionais destas espécies e ii) a ocorrência de anuros em um ambiente modificado, de matriz agrícola. Para a predição de categorias de ameaça e tendências populacionais utilizamos um banco de dados com atributos de habitat e modos reprodutivos de 3196 espécies de anuros neotropicais. Verificamos que espécies com modos reprodutivos terrestres e desenvolvimento direto tem uma maior tendência a estarem em declínio. Além disso, verificamos que embora os atributos sejam filogeneticamente estruturados, o grau de ameaça parece ser independente de suas histórias evolutivas. Para identificar possíveis relações entre atributos ecológicos e morfológicos de anuros em uma paisagem agrícola no sul do Brasil, registramos a anurofauna com uso de armadilhas de interceptação e queda e procuras ativas em três diferentes distâncias da borda em um ambiente florestal e em uma matriz agrícola. Verificamos que principalmente os atributos ecológicos, como o modo reprodutivo (tanto terrestre como aquático) e o hábito estão relacionados com a ocorrência destas espécies no sistema agrícola, assim como encontramos diferenças entre os atributos morfológicos ao longo do gradiente de distância. Ambos os resultados podem auxiliar na tomada de decisões em planos e projetos de conservação de anuros neotropicais.The extinction risk and population decline of many animal species in neotropical region are strongly related to anthropic processes, such as environmental conversion, but they are also related to intrinsic factors such as traits. Anurans correspond to the most endangered vertebrate group, suffering serious population declines. This work aimed to evaluate which neotropical anurans traits can predict: i) the categories of threat and population trends of species, and ii) the occurrence of anuran species in modified environments, such as the agricultural matrix. First, we compiled data to 3196 neotropical anuran species. We emphasized the importance of habitat and reproductive modes in threat classifications, as well as verified that species with terrestrial reproductive modes and direct development are more likely to be declining. We also found that although anurans traits being phylogenetically structured, the degree of threat seems to be independent from their evolutionary histories. In addition, to identify possible relation among ecological and morphological anuran traits with agricultural landscape in southern Brazil, we studied the anurofauna using pitfall traps and active searches at three different border distances in a forest environment and in an agricultural matrix. We verified that mostly of the ecological traits, such as the reproductive mode (both terrestrial and aquatic) and the habit, are related to the occurrence of determined species in the agricultural system. And we also found differences among the morphological traits observed through the distance gradient from the border. Therefore, both results present practical importance since it can help herpetologists to making decision about neotropical anurans conservation
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