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1.
Desmosomes entirely similar to those of the deeper layers of ruminal epithelium are seen in the luminal layers of the early fetal ruminal epithelium. In the older fetuses, these desmosomes have morphological features that reveal to some extent the occurrence of processes of keratinization. This could indicate that the basis for cell keratinization is already present in the fetus and that postnatal keratinization corresponds mainly to the full development of the prenatally existing pattern of differentiation. 相似文献
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P. Beer-Romero G. Rodríguez-Ochoa R. Angulo S. Cabrera L. Yarzábal 《Mycopathologia》1989,105(1):19-23
Six cases of sporotrichosis from the Orinoco river basin of Venezuela and Colombia are described; two are of the localized cutaneous type and four are lymphocutaneous. Diagnosis was based on the patient's clinical history and mycological culture. Epidemiology and distinctive cultural habits of the patients are discussed in connection with disease etiology.Abbreviations CAICET
Amazonas Center for Investigation and Control of Tropical Diseases
- TFA
Amazonas Federal Territory 相似文献
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Climate change is expected to affect natural populations in many ways. One way of getting an understanding of the effects of a changing climate is to analyze time series of natural populations. Therefore, we analyzed time series of 25 and 20 years, respectively, in two populations of the citril finch (Carduelis citrinella) to understand the background of a dramatic increase in wing length in this species over this period, ranging between 1.3 and 2.9 phenotypic standard deviations. We found that the increase in wing length is closely correlated to warmer winters and in one case to rain in relation to temperature in the summer. In order to understand the process of change, we implemented seven simulation models, ranging from two nonadaptive models (drift and sampling), and five adaptive models with selection and/or phenotypic plasticity involved and tested these models against the time series of males and females from the two population separately. The nonadaptive models were rejected in each case, but the results were mixed when it comes to the adaptive models. The difference in fit of the models was sometimes not significant indicating that the models were not different enough. In conclusion, the dramatic change in mean wing length can best be explained as an adaptive response to a changing climate. 相似文献
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Ants,Plants and Butterflies as Diversity Indicators: Comparisons between Strata at six Forest Sites in Venezuela 总被引:1,自引:0,他引:1
Frances Osborn William Goitia Maira Cabrera Klaus Jaffé 《Studies on Neotropical Fauna and Environment》2013,48(1):59-64
At six different forest sites in Venezuela, we estimated the diversity and abundance of ants and nymphalid butterflies on the ground and in the canopy, and of plants. Statistical analysis using eight different diversity indices for each species group revealed large variations among them. Ground ants appeared to be the most reliable bioindicators, even when only the five most common species are considered. Results showed in addition that ground ant diversity is correlated to that of canopy ants and that vegetational diversity is linked to butterfly diversity but not to that of canopy ants. Ant species diversity in the canopy was always less than that on the ground. We conclude that no simple index or single taxon describes completely complex ecosystems, thus, biodiversity assessments require tools still to be developed. 相似文献
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Species rear range edges are predicted to retract as climate warms, yet evidence of population persistence is accumulating. Accounting for this disparity is essential to enable prediction and planning for species’ range retractions. At the Mediterranean edge of European beech‐dominated temperate forest, we tested the hypothesis that individual performance should decline at the limit of the species’ ecological tolerance in response to increased drought. We sampled 40 populations in a crossed factor design of geographical and ecological marginality and assessed tree growth resilience and decline in response to recent drought. Drought impacts occurred across the rear edge, but tree growth stability was unexpectedly high in geographically isolated marginal habitat and lower than anticipated in the species’ continuous range and better‐quality habitat. Our findings demonstrate that, at the rear edge, range shifts will be highly uneven and characterised by reduction in population density with local population retention rather than abrupt range retractions. 相似文献
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Salvador?Peiru Andres?Aguirre Florencia?Eberhardt Mauricio?Braia Rodolfo?Cabrera Hugo?G.?MenzellaEmail author 《Biotechnology for biofuels》2015,8(1):223