111 resultados para Botswana


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Citizens of 9 different English-speaking countries (N = 619) evaluated the average, or typical, citizen of 5 English-speaking countries (Great Britain, Canada, Nigeria, United States, Australia) on 9 pairs of bipolar adjectives. Participants were drawn from Australia, Botswana, Canada, Kenya, Nigeria, South Africa, the United States, Zambia, and Zimbabwe. There were statistically significant similarities in the rankings of the 5 stimulus countries on 8 of the 9 adjective dimensions and a strong convergence of autostereotypes and heterostereotypes on many traits. The results relate to previous stereotyping research and traditional methods of assessing the accuracy of national stereotypes.

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Biological soil crusts (BSCs) are formed by aggregates of soil particles and communities of microbial organisms and are common in all drylands. The role of BSCs on infiltration remains uncertain due to the lack of data on their role in affecting soil physical properties such as porosity and structure. Quantitative assessment of these properties is primarily hindered by the fragile nature of the crusts. Here we show how the use of a combination of non-destructive imaging X-ray microtomography (XMT) and Lattice Boltzmann method (LBM) enables quantification of key soil physical parameters and the modeling of water flow through BSCs samples from Kalahari Sands, Botswana. We quantify porosity and flow changes as a result of mechanical disturbance of such a fragile cyanobacteria-dominated crust. Results show significant variations in porosity between different types of crusts and how they affect the flow and that disturbance of a cyanobacteria-dominated crust results in the breakdown of larger pore spaces and reduces flow rates through the surface layer. We conclude that the XMT–LBM approach is well suited for study of fragile surface crust samples where physical and hydraulic properties cannot be easily quantified using conventional methods.

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Wetlands are ecosystems commonly characterized by elevated levels of dissolved organic carbon (DOC), and although they cover a surface area less than 2 % worldwide, they are an important carbon source representing an estimated 15 % of global annual DOC flux to the oceans. Because of their unique hydrological characteristics, fire can be an important ecological driver in pulsed wetland systems. Consequently, wetlands may be important sources not only of DOC but also of products derived from biomass burning, such as dissolved black carbon (DBC). However, the biogeochemistry of DBC in wetlands has not been studied in detail. The objective of this study is to determine the environmental dynamics of DBC in different fire-impacted wetlands. An intensive, 2-year spatial and temporal dynamics study of DBC in a coastal wetland, the Everglades (Florida) system, as well as one-time sampling surveys for the other two inland wetlands, Okavango Delta (Botswana) and the Pantanal (Brazil), were reported. Our data reveal that DBC dynamics are strongly coupled with the DOC dynamics regardless of location, season or recent fire history. The statistically significant linear regression between DOC and DBC was applied to estimate DBC fluxes to the coastal zone through two main riverine DOC export routes in the Everglades ecosystem. The presence of significant amounts of DBC in these three fire-impacted ecosystems suggests that sub-tropical wetlands could represent an important continental-ocean carrier of combustion products from biomass burning. The discrimination of DBC molecular structure (i.e. aromaticity) between coastal and terrestrial samples, and between samples collected in wet and dry season, suggests that spatially-significant variation in DBC source strength and/or degree of degradation may also influence DBC dynamics.

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Students reflect more on their learning in course subjects when they participate in managing their teaching–learning environment. As a form of guided participation, peer assessment serves the following purposes: (a) it improves the student’s understanding of previously established learning objectives; (b) it is a powerful metacognitive tool; (c) it transfers to the student part of the responsibility for assessing learning, which means deciding which learning activities are important and choosing the degree of effort a course subject will require; (d) it emphasizes the collective aspect of the nature of knowledge; and (e) the educational benefits derived from peer assessment clearly justify the efforts required to implement activities. This paper reports on the relative merits of a learning portfolio compiled during fine arts-related studies in which peer assessment played an important role. The researchers analyzed the student work load and the final marks students received for compulsory art subjects. They conclude that the use of a closed learning portfolio with a well-structured, sequential and analytical design can have a positive effect on student learning and that, although implementing peer assessment may be complex and students need to become familiar with it, its use is not only feasible but recommendable.

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Ts’ixa is an endangered language of northern Botswana. It belongs to the Kalahari branch of the Khoe-Kwadi language family and is nowadays spoken by a small community of 200 individuals residing in the village of Mababe, Ngamiland. The internal affiliation of Ts’ixa within Kalahari Khoe is not clear, as the language displays affinities to both the western Kalahari Khoe language Khwe and the eastern Kalahari Khoe language Shua. The present work is the first attempt at providing a systematic description of Ts’ixa, based on phonological, morphological and syntactical features. Data from related Khoe languages, as well as from unrelated “Khoisan” languages of the Kx’a and Tuu families is used to locate Ts’ixa in both a genealogical and an areal framework. Findings suggest that Ts’ixa was shaped by a history of migration and contact between both related and unrelated languages, leading to a unique profile different from both Khwe and Shua, but with strong typological affinities to the Kalahari Basin as a linguistic area.

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El propósito de esta monografía es comprender cuál ha sido el rol de la Unión Africana (UA), dentro de la misión de paz AMISOM en el periodo de 2007- 2013. Por ello, el trabajo abarca aspectos geopolíticos e históricos, que han influido en la configuración del conflicto armado de Somalía y que han llevado progresivamente a la creación, evolución e implementación de mecanismos como las misiones de paz. Además, se abarcan los planteamientos del neo-funcionalismo y el neo-regionalismo para comprender las estructuras y las dinámicas propias de la UA y así, comprender la naturaleza tanto de sus acciones, como de sus propósitos; propósitos que aclaman el fomento del panafricanismo. Desde aquí se puede entender como su rol ha contribuido con el crecimiento del mercado de la industria militar en la región, a costa de la responsabilidad de proteger. Por último, se concluye que dichas dinámicas han llevado a la creación de comunidades de inseguridad.