884 resultados para Island endemics


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Esta tese centra-se em aspectos relevantes do inglês como uma língua universal, no actual contexto globalizado e examina possíveis mudanças relacionadas com o seu uso, em especial no continente africano, particularmente no caso de Cabo Verde, no sentido de ponderar eventuais alternativas nas pedagogias linguísticas no ensino desta língua que impliquem uma adaptação à realidade contemporânea. Uma vez que, nos nossos tempos, o inglês é a língua de eleição para a comunicação intercultural entre povos com várias experiências culturais e linguísticas, o conhecimento deste idioma torna-se, a cada dia que passa, impreterível e indispensável, na interacção intercultural. Em África, as funções desempenhadas pelo inglês são complexas; além da língua inglesa ser usada para comunicação entre etnias, com o estatuto de língua franca, também tem o papel de preservar a identidade nacional e de estabelecer a unidade entre os povos da mesma nação. Por conseguinte, é de considerar talvez ainda com mais pertinência, a adopção de uma nova filosofia de pedagogia de ensino que permita dotar os seus cidadãos de capacidades que lhes possibilitem comunicar de forma inteligível com povos de outras culturas e línguas. O primeiro capítulo aborda aspectos teóricos relacionados com a expansão, comunicação e mudança associadas à língua inglesa e suas implicações no ensino em países onde esta não é língua nativa (L1). O segundo capítulo reflecte, em primeiro lugar, sobre a situação linguística em África e as línguas francas predominantes no continente, incluindo a língua inglesa. Considera também questões relacionadas com o multilinguismo e a identidade, bem como assuntos relacionados com as implicações da diversidade linguística para a educação dos povos africanos.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Cabo Verde é um país com algum potencial no sector do agronegócios, representando cerca de trinta porcento (30%) dos rendimentos da população rural. Muito tem sido feito para melhorar este sector, contudo, devido à falta de espaço e de pastos, vem buscando alternativas mais viáveis para a criação de animais, que ocupam menos espaço e que produzam mais por m2. O número de aves domésticas em Cabo Verde foi estimada em 431.194, desses noventa e quatro porcento (94%) representava a criação de galinhas. A ilha de Santiago foi a maior produtora com quarenta e sete porcento (47%) dos efetivos, em seguida a ilha de São Vicente com vinte porcento (20%). Temperatura, instalações, nutrição e o manejo são variáveis importantes para o bem-estar animal e devem ser encarados em sinergia. Quando não estão de acordo com as necessidades mínimas exigidas levam as aves para fora da zona de conforto. A temperatura ideal para a criação de galinhas poedeiras na fase de produção deve rondar os 17 °C e os 28°C, e nos primeiros dias de vida de 33°C a 35°C. Em Cabo Verde ainda não existe a preocupação em proporcionar condições ideias para as aves de criação, visto que ainda é feita, na sua grande maioria, de forma tradicional e com pouca ou nenhuma tecnologia que vise um melhor desempenho produtivo das aves. Este trabalho teve como objetivos específicos: • Monitorizar o consumo de ração por aves; • Registar a postura diária e determinar a produção/produtividade; • Analisar os factores que afectam a produção/produtividade de ovos no aviário do INIDA;

Relevância:

20.00% 20.00%

Publicador:

Resumo:

We present the first approach to the genetic diversity and structure of the Balearic toad (Bufo balearicus Boettger, 1880) for the island of Menorca. Forty-one individ- uals from 21 localities were analyzed for ten microsatellite loci. We used geo-refer- enced individual multilocus genotypes and a model-based clustering method for the inference of the number of populations and of the spatial location of genetic dis- continuities between those populations.¦Only six of the microsatellites analyzed were polymorphic. We revealed a northwest- ern area inhabited by a single population with several well-connected localities and another set of populations in the southeast that includes a few unconnected small units with genetically significant differences among them as well as with the individ- uals from the northwest of the island. The observed fragmentation may be explained by shifts from agricultural to tourism practices that have been taking place on the island of Menorca since the 1960s. The abandonment of rural activities in favor of urbanization and concomitant service areas has mostly affected the southeast of the island and is currently threatening the overall geographic connectivity between the different farming areas of the island that are inhabited by the Balearic toad.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This paper presents the assessment and mapping of the Ribeira Seca catchment, an insular Sahelian mountain region sensitive to desertification, located on the island of Santiago, Cabo Verde. Desertification is a threat to the global environment, representing a serious ecological problemin Cabo Verde. To successfully combat desertification, an evaluation of desertification consequences is required and the building of cartography of the sensitivity for arid and semi-arid ecosystems is required as a first step. The MEDALUS model was the basis for this study in which six quality indicators were used: climate, soil, vegetation, land management, erosion and social factors. Several parameters were defined for each indicator with weights varying between 1 (very low) and 2 (very high). The geometric mean of each of the six quality indicators was employed to produce a map of areas sensitive to desertification. The results of this study show that more than 50% of the watershed show clear evidence of becoming a desertified area.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The pattern of genetic variation of the lizard Mabuya maculilabris from São Tomé Island (Gulf of Guinea) was investigated using a combination of three mitochondrial DNA gene fragments. Forty-eight haplotypes were recovered among 66 individuals covering the whole island. The genealogy inferred from the most parsimonious network of haplotypes allows us to detect two main and long branches departing from the putative group of oldest haplotypes. The tips of these branches exhibit star-like phylogenies, which may indicate of recently expanded populations, most probably from a small number of founders. A nested clade analysis suggests a complex pattern of past events that gave rise to the extant geographical pattern found in the haplotype distribution: past and allopatric fragmentation, range expansion, restricted gene Xow and long-distance dispersal. These results are consistent with the complex geological history of the island where important volcanic activity with extensive lava Xows has occurred during several periods. Mismatch- distribution analysis and AMOVA also support these conclusions. Substantial genetic structuring among these lizards was detected as well as high levels of diVerentiation between the southern edge populations (particularly those from the Rolas Islet) and the remaining ones. However, variation is low relative to the geological age of the island. Our results indicate that patterns of variation observed in reptiles in other oceanic islands are not indicative of those observed in the islands of the Gulf of Guinea.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

New distribution record of Cybocephalus Kathrynae (Coleoptera, Cybocephalidae) on Mona Island, Puerto Rico. A new record of Cybocephalus kathrynae T.R. Smith (Cybocephalidae) is reported for Puerto Rico. Adults were collected from the flowers of Mammillaria nivosa (Cactaceae) on Mona Island Reserve. Prior to this study, this beetle species was only reported for Monroe and Miami-Dade Counties, Florida, USA.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Ten microsatellite loci and a partial sequence of the COII mitochondrial gene were used to investigate genetic differentiation in B. terrestris, a bumble bee of interest for its high-value crop pollination. The analysis included eight populations from the European continent, five from Mediterranean islands (six subspecies altogether) and one from Tenerife (initially described as a colour form of B. terrestris but recently considered as a separate species, B. canariensis). Eight of the 10 microsatellite loci displayed high levels of polymorphism in most populations. In B. terrestris populations, the total number of alleles detected per polymorphic locus ranged from 3 to 16, with observed allelic diversity from 3.8 +/- 0.5 to 6.5 +/- 1.4 and average calculated heterozygosities from 0.41 +/- 0.09 to 0.65 +/- 0.07. B. canariensis showed a significantly lower average calculated heterozygosity (0.12 +/- 0.08) and observed allelic diversity (1.5 +/- 0.04) as compared to both continental and island populations of B. terrestris. No significant differentiation was found among populations of B. terrestris from the European continent. In contrast, island populations were all significantly and most of them strongly differentiated from continental populations. B. terrestris mitochondrial DNA is characterized by a low nucleotide diversity: 0.18% +/- 0.07%, 0.20% +/- 0.04% and 0.27% +/- 0.04% for the continental populations, the island populations and all populations together, respectively. The only haplotype found in the Tenerife population differs by a single nucleotide substitution from the most common continental haplotype of B. terrestris. This situation, identical to that of Tyrrhenian islands populations and quite different from that of B. lucorum (15 substitutions between terrestris and lucorum mtDNA) casts doubts on the species status of B. canariensis. The large genetic distance between the Tenerife and B. terrestris populations estimated from microsatellite data result, most probably, from a severe bottleneck in the Canary island population. Microsatellite and mitochondrial DNA data call for the protection of the island populations of B. terrestris against importation of bumble bees of foreign origin which are used as crop pollinators.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

To evaluate the role of garnet and amphibole fractionation at conditions relevant for the crystallization of magmas in the roots of island arcs, a series of experiments were performed on a synthetic andesite at conditions ranging from 0.8 to 1.2 GPa, 800-1,000 degrees C and variable H2O contents. At water undersaturated conditions and fO(2) established around QFM, garnet has a wide stability field. At 1.2 GPa garnet ? amphibole are the high-temperature liquidus phases followed by plagioclase at lower temperature. Clinopyroxene reaches its maximal stability at H2O-contents <= 9 wt% at 950 degrees C and is replaced by amphibole at lower temperature. The slopes of the plagioclase-in boundaries are moderately negative in T-XH2O space. At 0.8 GPa, garnet is stable at magmatic H2O contents exceeding 8 wt% and is replaced by spinel at decreasing dissolved H2O. The liquids formed by crystallization evolve through continuous silica increase from andesite to dacite and rhyolite for the 1.2 GPa series, but show substantial enrichment in FeO/MgO for the 0.8 GPa series related to the contrasting roles of garnet and amphibole in fractionating Fe-Mg in derivative liquids. Our experiments indicate that the stability of igneous garnet increases with increasing dissolved H2O in silicate liquids and is thus likely to affect trace element compositions of H2O-rich derivative arc volcanic rocks by fractionation. Garnet-controlled trace element ratios cannot be used as a proxy

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A delta(34)S value of +6.3 +/- 1.5% was estimated for the rhyodacitic degassing magma present underneath the hydrothermal system of Nisyros, based on the S isotope ratios of H2S in fumarolic vapors. This value was estimated by modeling the irreversible water-rock mass transfers occurring during the generation of the hydrothermal liquid which separates these fumarolic vapors. The S isotope ratio of the rhyodacitic degassing magma of Nisyros is consistent with fractional crystallization of a parent basaltic magma with an initial delta(34)S value of +4% (+/-at least 1.5%). This positive value could be explained by mantle contamination due to by either transference of fluids derived from subducted materials or involvement of altered oceanic crust, whereas contribution of biogenic sulfides from sediments seems to be negligible or nil. This conclusion agrees with the lack of N-2 and CO2 from thermal decomposition of organic matter contained in subducted sediments, which is a characteristic of the whole Aegean arc system. Since hydrothermal S at Milos and Santorini has isotope ratios similar to those determined at Nisyros, it seems likely that common controlling processes are active throughout the Aegean island arc. (C) 2002 Elsevier, Science B.V. All rights reserved.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

AimSmall body size in Madagascar's dwarf and mouse lemurs (Cheirogaleidae) is generally viewed as primitive. We investigated the evolution of body size in this family and in its sister-taxon, the Lepilemuridae, from phylogenetic, ontogenetic and adaptive perspectives. LocationMadagascar. MethodsWe used a phylogenetic method to reconstruct the evolution of body size in lemurs, and allometric regression models of gestation periods and static and growth allometries in Cheirogaleidae and Lepilemuridae to test the hypothesis that dwarfing occurred as a result of truncated ontogeny (progenesis). We also examined adaptive hypotheses relating body size to environmental variability, life history, seasonality of reproduction, hypothermy (use of torpor), and a diet rich in plant exudates. ResultsOur results indicated that cheirogaleids experienced at least four independent events of body size reduction from an ancestor as large as living Lepilemuridae, by means of progenesis. Our interpretation is supported by the paedomorphic appearance and parallel ontogenetic trajectories of the dwarf taxa, as well as their very short gestation periods and increased fecundity. Lepilemur species that occupy more predictable environments are significantly larger than those occupying unpredictable habitats. Main conclusionsCheirogaleidae appear to be paedomorphic dwarfs, a consequence of progenesis, probably as an adaptation to high environmental unpredictability. Although the capacity to use hypothermy is related to small body size, this advantage is unlikely to have driven dwarfing in cheirogaleids. We propose that gummmivory/exudativory co-evolved with body size reduction in this clade, probably from a folivorous ancestor. Their small size is derived, and their suitability as models for the ancestral primate' is therefore dubious.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In human transcriptional regulation, DNA-sequence-specific factors can associate with intermediaries that orchestrate interactions with a diverse set of chromatin-modifying enzymes. One such intermediary is HCFC1 (also known as HCF-1). HCFC1, first identified in herpes simplex virus transcription, has a poorly defined role in cellular transcriptional regulation. We show here that, in HeLa cells, HCFC1 is observed bound to 5400 generally active CpG-island promoters. Examination of the DNA sequences underlying the HCFC1-binding sites revealed three sequence motifs associated with the binding of (1) ZNF143 and THAP11 (also known as Ronin), (2) GABP, and (3) YY1 sequence-specific transcription factors. Subsequent analysis revealed colocalization of HCFC1 with these four transcription factors at ∼90% of the 5400 HCFC1-bound promoters. These studies suggest that a relatively small number of transcription factors play a major role in HeLa-cell transcriptional regulation in association with HCFC1.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Freud defined the drive as "a concept on the frontier between the mental and the somatic". Today this view that was based on clinical observations interpreted within the psychoanalytical framework, can be revisited in light of the current neuroscientific notions of neuronal plasticity and somatic states. Indeed, through the mechanisms of plasticity experience leaves a trace that forms the neural basis of a representation of the experience. Such a representation R is associated with a somatic state S in the sense taken from the "somatic marker" model of Damasio. Thus, the internal reality of the subject, particularly the unconscious one, is constituted by such connected R's and S's. In the model that we discuss, the posterior insula represents the primary interoceptive cortex where information about somatic states S converges, while in the anterior insula the connection between R and S can take place and establish a neurobiological correlate for the notion of drive. We posit that the re-representations of S associated with R in the anterior insula may correspond to the Vorstellungsrepräsentanz postulated by Freud. We further propose that the tension between R and S established in the anterior insula is discharged according to the notion of drive through the motor arm of the limbic system, namely the anterior cingulate cortex which is heavily connected with the anterior insula.