2,353 research outputs found

    Two new Lejeuneaceae records for the Colombian liverwort flora

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    Two epiphyllous Lejeuneaceae, Cololejeunea surinamensis and Drepanolejeunea polyrhiza, previously known from Amazonian Brazil, are recorded for the first time in Colombia. They were found as epiphylls on understory shrubs in the middle Caquetá area in Colombian Amazonia. Cololejeunea surinamensis was found in the Tierra Firme forests and D. polyrhiza was found in the floodplains of the Caquetá River.Dos especies de Lejeuneaceae epífilas, Cololejeunea surinamensis y Drepanolejeunea polyrhiza, previamente conocidas de los bosques amazónicos de Brasil son reportadas por primera vez para Colombia. Las especies fueron encontradas como epífilas sobre hojas de arbustos del sotobosque en el área del medio Caquetá en la amazonía Colombiana. Cololejeunea surinamensis fue encontrada en los bosques de tierra firme, mientras que D. polyrhiza fue encontrada en los planos inundables del Río Caquetá

    Bryophyte diversity patterns in flooded and tierra firme forests in the Araracuara Region, Colombian Amazonia

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    We investigated patterns of bryophyte species richness and composition in two forest types of Colombian Amazonia, non-flooded tierra firme forest and floodplain forest of the Caquetá River. A total of 109 bryophyte species were recorded from 14 0.2 ha plots. Bryophyte life forms and habitats were analyzed, including the canopy and epiphylls. Bryophyte species did not show significant differences between landscapes but mosses and liverworts were different and with opposite responses balancing the overall richness. Independence test showed differences in both life form and habitat use distribution between the two forest types with more fan and mat bryophytes species in the floodplains, and more epiphytic liverworts in the tierra firme forest. Correspondence analysis showed differences in the bryophyte species assemblage between the two forest types where they may be responding to the higher humidity provided by the flooding. Despite of, the environmental differences detected, epiphyll species assemblages were not strongly affected. Apparently, epiphyll habitat is stressful enough to hide the environmental differences between the flooded and Tierra firme forests.Investigamos los patrones de riqueza de especies y composición florística de briofitos en dos tipos de bosque en la Amazonía Colombiana. Bosques no inundados de Tierra firme y bosques periódicamente inundados en los planos inundables del Rió Caquetá. Encontramos 109 especies de briofitos en 14 parcelas de 0.2 ha. Nosotros analizamos diferencias en la distribución de formas de vida y hábitat de los briofitos entre los dos tipos de bosque incluyendo especies del dosel y epifilas. El número de especies de briofitos no mostró diferencias significativas entre los dos tipos de bosque. Pero musgos y hepáticas si tuvieron diferencias con respuestas opuestas balanceando el número total de especies. Pruebas de independencia mostraron diferencias en la distribución de formas de vida y uso de hábitat entre los dos tipos de bosque con más especies de abanicos y esteras en los planos inundables, y más especies de hepáticas epifitas en el bosque de Tierra firme. El análisis de correspondencia mostró diferencias en la composición florística de briofitos entre ambos tipos de bosque, donde las comunidades de briofitos pueden estar respondiendo a un gradiente de humedad aportada por la inundación periódica de los planos inundables. La composición florística de los briofitos epifilos no mostró una separación tan clara entre los tipos de bosque como si fue detectada en los otros hábitat donde los briofitos fueron encontrados. Aparentemente, el hábitat epifilo es suficientemente estresante para ocultar el efecto de las diferentes condiciones ambientales de los bosques inundables y de Tierra firme

    A glossary for the social epidemiology of work organization. Part 3: terms from labour markets

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    This is part 3 of a three-part glossary on the social epidemiology of work organisation. The first two parts deal with the social psychology of work and with organisations. This concluding part presents concepts related to labour markets. These concepts are drawn from economics, business and sociology. They relate both to traditional interests in these disciplines and to contemporary ideas on post-industrialisation and globalisation, particularly the growth of employment in service industries, the development of a 24-h economy, increased participation of the female labour force and the perceived needs of employers in emerging high-tech economies.These changes are of particular interest because they are linked to increasing inequality in earnings and changes in social relationships in employment. These concepts have the potential to elucidate the pathways through which health is affected by conditions of work as an underlying cause

    El clítico “se” en español y la estructura léxico conceptual

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    Poco se ha escrito sobre el papel que la Estructura Léxico-Conceptual juega en la semántica del español. El presente trabajo analiza la entrada léxica del clítico "se", englobando sus funciones media y reflexiva, y los verbos con los cuales se asocia (por ejemplo, quebrarse). Dentro del marco de la gramática generativa, el artículo propone un modelo de representación léxica donde tanto la Estructura Léxico-Conceptual como el mecanismo de percolación juegan un papel crítico en la derivación e interpretación de verbos en español formados con se. Se exploran además las ventajas que el modelo propuesto tiene en relación con otros modelos de representación léxica. Finalmente, se propone un método que facilita la enseñanza y aprendizaje de este clítico en las clases de español de cualquier nivel. Relatively little research has been devoted to the role that Lexical Conceptual Structure plays in the semantics of Spanish. The present study analyzes the lexical entry of the se pronoun, covering its average and reflexive functions, as well as the verbs with which it is associated (e.g. quebrarse). Within the generative framework, the article proposes a model of lexical representation where both Lexical Conceptual Structure and the mechanism of percolation play a critical role in the derivation and interpretation of Spanish verbs with se. In addition, the article explores that the advantages the proposed model has over other models of lexical representation. Finally, a method is proposed which facilitates the teaching and learning of this pronoun in our Spanish courses, at any level

    Quasipinning and selection rules for excitations in atoms and molecules

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    Postulated by Pauli to explain the electronic structure of atoms and molecules, the exclusion principle establishes an upper bound of 1 for fermionic natural occupation numbers {ni }. A recent analysis of the pure N-representability problem provides a wide set of inequalities for the {ni}, leading to constraints on these numbers. This has a strong potential impact on reduced density matrix functional theory as we know it. In this work we continue our study of the nature of these inequalities for some atomic and molecular systems. The results indicate that (quasi)saturation of some of them leads to selection rules for the dominant configurations in configuration interaction expansions, in favorable cases providing means for significantly reducing their computational requirements

    An Analysis of Seed Colour During Ripening of Cabernet Sauvignon Grapes

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    This case study examines seed colour during ripening using an exhaustive colorimetric analysis. The aim was to associate the chemical ripening with the seed colour in order to estimate the ripening stages of Cabernet Sauvignon grapes. Cluster samples, obtained from a vertical shoot-positioned vineyard in central Chile, were monitored for their technological and phenolic maturity, as well as for the colorimetric and chemical characteristics of the seeds. The colours of the scanned seed images were determined by human as well as by computer vision. In the first case, an expert assigned a colour to each seed part. In the second case, a computer program estimated the colours of the scanned seed images. An exhaustive analysis of seed colour was proposed, instead of a general observation of seed browning. The seed colour presented a wide range of colours, from moss green to dark brown, depending on the maturity and the face observed. The ripening stages identified, along with the chemical and colorimetric information gathered, were under ripe seed (brown with green traces), ripe seed (dark brown with green traces) and overripe seed (dark brown without any green traces). A new way to quantify seed colour is shown in this paper

    A new clinical tool for assessing numerical abilities in neurological diseases: numerical activities of daily living

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    The aim of this study was to build an instrument, the numerical activities of daily living (NADL), designed to identify the specific impairments in numerical functions that may cause problems in everyday life. These impairments go beyond what can be inferred from the available scales evaluating activities of daily living in general, and are not adequately captured by measures of the general deterioration of cognitive functions as assessed by standard clinical instruments like the MMSE and MoCA. We assessed a control group (n = 148) and a patient group affected by a wide variety of neurological conditions (n = 175), with NADL along with IADL, MMSE, and MoCA. The NADL battery was found to have satisfactory construct validity and reliability, across a wide age range. This enabled us to calculate appropriate criteria for impairment that took into account age and education. It was found that neurological patients tended to overestimate their abilities as compared to the judgment made by their caregivers, assessed with objective tests of numerical abilities
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