991 resultados para CAPE HONEYBEE


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The chromosome number of Gracilaria verrucosa (Hudson) Papenfuss was estimated in numerous individuals from different populations of the Cape Gris-Nez area of Northern France. To optimize estimates and to minimize counting errors, several counts were made on the same nucleus and in different nuclei of the same individual. The haploid chromosome number was estimated in vegetative gametophytic cells and tetrasporocytic cells; the diploid number was estimated from tetrasporophytic vegetative cells. The basic haploid number was n = 17 +/- 1, whereas all other Gracilaria species for which chromosome numbers are available are reported to have n = 24. These include populations of G. verrucosa from Norway and Wales that have previously been shown to be conspecific with the Cape Gris-Nez populations by comparison of plastid DNA data. G. verrucosa is therefore one of the few red algae for which populations with different chromosome numbers are known.

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Organisms respond to cyclical environmental conditions by entraining their endogenous biological rhythms. Such physiological responses are expected to be substantial for species inhabiting arid environments which incur large variations in daily and seasonal ambient temperature (T). We measured core body temperature (T) daily rhythms of Cape ground squirrels Xerus inauris inhabiting an area of Kalahari grassland for six months from the Austral winter through to the summer. Squirrels inhabited two different areas: an exposed flood plain and a nearby wooded, shady area, and occurred in different social group sizes, defined by the number of individuals that shared a sleeping burrow. Of a suite of environmental variables measured, maximal daily T provided the greatest explanatory power for mean T whereas sunrise had greatest power for T acrophase. There were significant changes in mean T and T acrophase over time with mean T increasing and T acrophase becoming earlier as the season progressed. Squirrels also emerged from their burrows earlier and returned to them later over the measurement period. Greater increases in T, sometimes in excess of 5°C, were noted during the first hour post emergence, after which T remained relatively constant. This is consistent with observations that squirrels entered their burrows during the day to 'offload' heat. In addition, greater T amplitude values were noted in individuals inhabiting the flood plain compared with the woodland suggesting that squirrels dealt with increased environmental variability by attempting to reduce their T-T gradient. Finally, there were significant effects of age and group size on T with a lower and less variable T in younger individuals and those from larger group sizes. These data indicate that Cape ground squirrels have a labile T which is sensitive to a number of abiotic and biotic factors and which enables them to be active in a harsh and variable environment.

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There is increasing appreciation that hosts in natural populations are subject to infection by multiple parasite species. Yet the epidemiological and ecological processes determining the outcome of mixed infections are poorly understood. Here, we use two intracellular gut parasites (Microsporidia), one exotic and one co-evolved in the western honeybee (Apis mellifera), in an experiment in which either one or both parasites were administered either simultaneously or sequentially. We provide clear evidence of within-host competition; order of infection was an important determinant of the competitive outcome between parasites, with the first parasite significantly inhibiting the growth of the second, regardless of species. However, the strength of this ‘priority effect’ was highly asymmetric, with the exotic Nosema ceranae exhibiting stronger inhibition of Nosema apis than vice versa. Our results reveal an unusual asymmetry in parasite competition that is dependent on order of infection. When incorporated into a mathematical model of disease prevalence, we find asymmetric competition to be an important predictor of the patterns of parasite prevalence found in nature. Our findings demonstrate the wider significance of complex multi-host–multi-parasite interactions as drivers of host–pathogen community structure

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This paper focuses attention on the fortunes of Darwin's theory among the English-speaking community in Cape Colony during the latter part of the nineteenth century. The paper begins with a review of early encounters with Darwin dwelling particularly on the response of figures like Roderick Noble - professor and editor of the Cape Monthly Magazine, the geologist John Shaw, and Sir Henry Barkly, governor of the colony. Besides these more theoretical responses, Darwin's ideas were also mobilised in a range of scientific inquiries on such subjects as birds and butterflies. But most conspicuous was the use of evolutionary thought-forms in the work of the eminent philologist Wilhelm Bleek, cousin of Darwin's leading German apologist, Ernst Haeckel. The prevailing sense is of a liberal intelligentsia calmly interacting with a novel theory with all due deference. During the 1870s, an address by Langham Dale at the South African Public Library injected new energy into the Darwin discussion. Dale expressed disquiet over some of the anthropological implications of evolution as well as its apparent reductionism, and this stimulated a range of reactions. Several anonymous commentators responded but the most sustained evaluation of Dale's position emanated from the Queenstown physician and later politician, Sir William Bisset Berry. Then, in 1874, copious extracts from John Tyndall's infamous 'Belfast Address' were printed in the Cape Monthly and this added yet further impetus to the debate. Tyndall's seeming materialism bothered a number of readers, not least Hon William Porter, former attorney-general of Cape Colony. To figures like these the materialist extrapolations of radical Darwinians such as Haeckel were deeply disturbing, not just for religious reasons, but because they seemed to destabilise the moral and pedagogic progressivism that lay at the heart of their civilising credo. While reservations about Darwin's proposals were certainly audible, taken in the round Darwinian conversations among the English-speaking literati at the Cape were conducted with liberal sentiments, not least when evolutionary science approached questions of race. For Darwin's writings were seen to confirm a monogenetic account of the origin and unity of the human race, and could readily be called upon to justify the paternalistic ideology that governed colonial affairs.

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A Ilha de Santiago, situada no Arquipélago de Cabo Verde, é dominada por um clima seco e árido, interrompido por curtos períodos de chuvas torrenciais, com grande capacidade de transporte de sedimentos ao longo de vales profundos e encaixados, tributários da Ribeira Seca, onde se situa a Barragem do Poilão, construída em 2006. Os resultados de um levantamento batimétrico da albufeira da barragem realizado em Março de 2013, apontam para uma taxa de sedimentação anual próxima de 90 000 m3 /ano, fazendo com que, em apenas 7, anos a capacidade de armazenamento da albufeira tenha diminuído quase para metade. Os valores determinados neste estudo recomendam a tomada de medidas urgentes por parte do governo de Cabo Verde, no sentido da dragagem e desassoreamento da albufeira do Poilão.

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Poilão dam reservoir (Cape Verde Archipelago) is in critical conditions, owing the excessive silting up, the high concentration of nitrates and the pronounced anoxia all over the lake. Considering that the most suitable remediation strategy is the removal of the bottom sediments where nutrients are preferentially concentrated, we have done a geochemical study, in order of evaluating their suitability to agricultural use. Analyses indicate that sediments are rich in a few key nutrients, when compared with parent soils. Thus, adding suitable sediments to nearby degraded soils can improve food crops for smallholder farmers living in close proximity to this system.

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In 2004, the Calouste Gulbenkian Foundation invited the University of Aveiro to develop an education and training program in advanced topics of ICT for Cape Verde. The focus should be on technologies to support the development of distance education. Two years later, when the program was started, the University of Aveiro had a high-performance videoconferencing Studio installed by the Foundation for National Scientific Computing. However, the investment to duplicate this high quality structure and operating costs were not compatible neither with the project’s budget nor with the technological options available in Cape Verde. This paper demonstrates the decision-making process by an economically viable option to meet the needs and local peculiarities.

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Tese de dout., Ciências e Tecnologia das Pescas, Faculdade de Ciências do Mar e do Ambiente, Universidade do Algarve, 2005

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This study attempts to implement a hydrodynamic operational model which can ultimately be used for projecting oil spill dispersal patterns and also sewage, pollution and can also be used in wave forecasting. A two layer nested model was created using MOHID Water, which is powerful ocean modelling software. The first layer (father) is used to impose the boundary conditions for the second layer (son). This was repeated for two different wind dominant regimes, Easterly and Westerly winds respectively. A qualitative comparison was done between measured tidal data and the tidal output. Sea surface temperature was also qualitatively compared with the model’s results. The results from both simulations were analysed and compared to historical literature. The comparison was done at the surface layer, 100 metre depth and at 800m depth. In the surface layer the first simulation generated an upwelling event near Cape St. Vincent and within the Algarve. The second simulation generated a non-upwelling event within which the surface was flow reversed and the warm water mass was along the Algarve coastline and evening turning clockwise around Cape St. Vincent. At the 100 metre depth for both simulations, velocity vortexes were observed near Cape St. Vincent travelling northerly and southerly at various instances. At 800metre depth a strong oceanic flow was observed moving north westerly along the continental shelf.

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The loggerhead turtle (Caretta caretta) is an endangered marine reptile for whom assessing population health requires knowledge of demographic parameters such as individual growth rate. In Cape Verde, as within several populations, adult female loggerhead sea turtles show a size-related behavioral and trophic dichotomy. While smaller females are associated with oceanic habitats, larger females tend to feed in neritic habitats, which is reflected in their physiological condition and in their offspring. The ratio of RNA/DNA provides a measure of cellular protein synthesis capacity, which varies depending on changes in environmental conditions such as temperature and food availability. The purpose of this study was to evaluate the combined use of morphometric data and biochemical indices as predictors of the physiological condition of the females of distinct sizes and hatchlings during their nesting season and how temperature may influence the physiological condition on the offspring. Here we employed biochemical indices based on nucleic acid derived indices (standardized RNA/DNA ratio-sRD, RNA concentration and DNA concentration) in skin tissue as a potential predictor of recent growth rate in nesting females and hatchling loggerhead turtles. Our major findings were that the physiological condition of all nesting females (sRD) decreased during the nesting season, but that females associated with neritic habitats had a higher physiological condition than females associated with oceanic habitats. In addition, the amount of time required for a hatchling to right itself was negatively correlated with its physiological condition (sRD) and shaded nests produced hatchlings with lower sRD. Overall, our results showed that nucleic acid concentrations and ratios of RNA to DNA are an important tool as potential biomarkers of recent growth in marine turtles. Hence, as biochemical indices of instantaneous growth are likely temperature-, size- and age-dependent, the utility and validation of these indices on marine turtles stocks deserves further study.

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Tese de doutoramento, Geologia (Geoquímica), Universidade de Lisboa, Faculdade de Ciências, 2014

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Ensuring sustainable development conditions is presently world widely recognized as a critically important goal. This makes the use of electricity generation technologies based on renewable energy sources very relevant. Developing countries depend on an adequate availability of electrical energy to assure economic progress and are usually characterized by a high increase in electricity consumption. This makes sustainable development a huge challenge but it can also be taken as an opportunity, especially for countries which do not have fossil resources. This paper presents a study concerning the expansion of an already existent wind farm, located in Praia, the capital of Cape Verde Republic. The paper includes results from simulation studies that have been undertaken using PSCAD software and some economic considerations.

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Are return migrants more productive than non-migrants? If so, is it a causal effect or simply self-selection? Existing literature has not reached a consensus on the role of return migration for origin countries. To answer these research questions, an empirical analysis was performed based on household data collected in Cape Verde. One of the most common identification problems in the migration literature is the presence of migrant self-selection. In order to disentangle potential selection bias, we use instrumental variable estimation using variation provided by unemployment rates in migrant destination countries, which is compared with OLS and Nearest Neighbor Matching (NNM) methods. The results using the instrumental variable approach provide evidence of labour income gains due to return migration, while OLS underestimates the coefficient of interest. This bias points towards negative self-selection of return migrants on unobserved characteristics, although the different estimates cannot be distinguished statistically. Interestingly, migration duration and occupational changes after migration do not seem to influence post-migration income. There is weak evidence that return migrants from the United States have higher income gains caused by migration than the ones who returned from Portugal.

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This work project consists of a comprehensive study of the possibility of opening a Wealth Management (WM) firm located in Cape Verde (CV), and was made at the request of NovoBanco’s Research Sectorial team. WM is a growing industry that consists in the set of financial services provided to wealthy clients. After taking into account the expected industry growth of the Sub-Saharan region, the preferences of the African wealthy, the current industry structure, and the advantages and disadvantages of locating a WM business in CV, it is concluded that a business opportunity exists. The reasons for thus, along with relevant recommendations, including which services a new business should offer and whom to target specifically, are presented in the final section.