957 resultados para SOUTH AMERICAN FRUIT FLY


Relevância:

100.00% 100.00%

Publicador:

Resumo:

El artículo trata sobre diferentes visiones de la política exterior brasilera. Primero introduce las principales directivas de la política exterior: desarrollo económico y social, así como delimitación limítrofe con los países de América del Sur. La segunda establece la situación de las relaciones de Brasil luego de la guerra fría, con algunos países y regiones en el mundo: Estados Unidos, Unión Europea, América Latina, China, África, India y otras regiones. Finalmente se refiere a los intereses nacionales brasileros en las Naciones Unidas en campos como energía, medio ambiente y defensa.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Since the creation of Union of South American Nations (UNASUR), health policies have become a strategic element in dealing with the impact of neoliberal policies in the region. The aim of this paper is: first, to describe the social, political and economic processes that explain the emergence of UNASUR and its focus on social policy through health care, and second, how through UNASUR Health, health became the engine behind a new kind of health diplomacy. This article hopes to contribute to the debate on the new forms of health diplomacy and the role of regional organizations concentrating on health policies as a centrepiece of their regional integration efforts and the reduction of social inequalities.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This article starts by considering the fact that the Guyanas can be understood as an atypical region in the Latin-American context. The lapse of analysis of this study is from 1600 to 1814, period of development of Dutch Guyanas, which was the base of the Surinam Republic and the Co-operative Republic of Guyana. These are highlighted for being the unique Latin-American entities that were not colonized by the Catholics Monarchies, for the absence of missionary activities until 1735, and also for the absence of private action. These colonies offer an interesting study field about comparative development with other South American regions.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Understanding and predicting changes in storm tracks over longer time scales is a challenging problem, particularly in the North Atlantic. This is due in part to the complex range of forcings (land–sea contrast, orography, sea surface temperatures, etc.) that combine to produce the structure of the storm track. The impact of land–sea contrast and midlatitude orography on the North Atlantic storm track is investigated through a hierarchy of GCM simulations using idealized and “semirealistic” boundary conditions in a high-resolution version of the Hadley Centre atmosphere model (HadAM3). This framework captures the large-scale essence of features such as the North and South American continents, Eurasia, and the Rocky Mountains, enabling the results to be applied more directly to realistic modeling situations than was possible with previous idealized studies. The physical processes by which the forcing mechanisms impact the large-scale flow and the midlatitude storm tracks are discussed. The characteristics of the North American continent are found to be very important in generating the structure of the North Atlantic storm track. In particular, the southwest–northeast tilt in the upper tropospheric jet produced by southward deflection of the westerly flow incident on the Rocky Mountains leads to enhanced storm development along an axis close to that of the continent’s eastern coastline. The approximately triangular shape of North America also enables a cold pool of air to develop in the northeast, intensifying the surface temperature contrast across the eastern coastline, consistent with further enhancements of baroclinicity and storm growth along the same axis.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

In this study, complementary species-level and intraspecific phylogenies were used to better circumscribe the original native range and history of translocation of the invasive tree Parkinsonia aculeata. Species-level phylogenies were reconstructed using three chloroplast gene regions, and amplified fragment length polymorphism (AFLP) markers were used to reconstruct the intraspecific phylogeny. Together, these phylogenies revealed the timescale of transcontinental lineage divergence and the likely source of recent introductions of the invasive. The sequence data showed that divergence between North American and Argentinean P. aculeata occurred at least 5.7 million years ago, refuting previous hypotheses of recent dispersal between North and South America. AFLP phylogenies revealed the most likely sources of naturalized populations. The AFLP data also identified putatively introgressed plants, underlining the importance of wide sampling of AFLPs and of comparison with uniparentally inherited marker data when investigating hybridizing groups. Although P. aculeata has generally been considered North American, these data show that the original native range of P. aculeata included South America; recent introductions to Africa and Australia are most likely to have occurred from South American populations.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Despite continuing developments in information technology and the growing economic significance of the emerging Eastern European, South American and Asian economies, international financial activity remains strongly concentrated in a relatively small number of international financial centres. That concentration of financial activity requires a critical mass of office occupation and creates demand for high specification, high cost space. The demand for that space is increasingly linked to the fortunes of global capital markets. That linkage has been emphasised by developments in real estate markets, notably the development of global real estate investment, innovation in property investment vehicles and the growth of debt securitisation. The resultant interlinking of occupier, asset, debt and development markets within and across global financial centres is a source of potential volatility and risk. The paper sets out a broad conceptual model of the linkages and their implications for systemic market risk and presents preliminary empirical results that provide support for the model proposed.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Oxygen isotope records of stalagmites from China and Oman reveal a weak summer monsoon event, with a double-plunging structure, that started 8.21 ± 0.02 kyr B.P. An identical but antiphased pattern is also evident in two stalagmite records from eastern Brazil, indicating that the South American Summer Monsoon was intensified during the 8.2 kyr B.P. event. These records demonstrate that the event was of global extent and synchronous within dating errors of <50 years. In comparison with recent model simulations, it is plausible that the 8.2 kyr B.P. event can be tied in changes of the Atlantic Meridional Overturning Circulation triggered by a glacial lake draining event. This, in turn, affected North Atlantic climate and latitudinal position of the Intertropical Convergence Zone, resulting in the observed low-latitude monsoonal precipitation patterns.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

We used fossil pollen to investigate the response of the eastern Chiquitano seasonally-dry tropical forest (SDTF), lowland Bolivia, to high-amplitude climate change associated with glacial–interglacial cycles. Changes in the structure, composition and diversity of the past vegetation are compared with palaeoclimate data previously reconstructed from the same record, and these results shed light on the biogeographic history of today’s highly disjunct blocks of SDTF across South America. We demonstrate that lower glacial temperatures limited tropical forest in the Chiquitanía region, and suggest that SDTF was absent or restricted at latitudes below 17°S, the proposed location of the majority of the hypothesized ‘Pleistocene dry forest arc’ (PDFA). At 19500 yrs b.p., warming supported the establishment of a floristically-distinct SDTF, which showed little change throughout the glacial–Holocene transition, despite a shift to significantly wetter conditions beginning ca. 12500–12200 yrs b.p. Anadenanthera colubrina, a key SDTF taxon, arrived at 10000 yrs b.p., which coincides with the onset of drought associated with an extended dry season. Lasting until 3000 yrs b.p., Holocene drought caused a floristic shift to more drought-tolerant taxa and a reduction in α-diversity (shown by declining palynological richness), but closed-canopy forest was maintained throughout. In contrast to the PDFA, the modern distribution of SDTF most likely represents the greatest spatial coverage of these forests in southern South America since glacial times. We find that temperature is a key climatic control upon the distribution of lowland South American SDTF over glacial-interglacial timescales, and seasonality of rainfall exerts a strong control on their floristic composition.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The response of the six major summer monsoon systems (the North American monsoon, the northern Africa monsoon, the Asia monsoon, the northern Australasian monsoon, the South America monsoon and the southern Africa monsoon) to mid-Holocene orbital forcing has been investigated using a coupled ocean–atmosphere general circulation model (FOAM), with the focus on the distinct roles of the direct insolation forcing and oceanic feedback. The simulation result is also found to compare well with the NCAR CSM. The direct effects of the change in insolation produce an enhancement of the Northern Hemisphere monsoons and a reduction of the Southern Hemisphere monsoons. Ocean feedbacks produce a further enhancement of the northern Africa monsoon and the North American monsoon. However, ocean feedbacks appear to weaken the Asia monsoon, although the overall effect (direct insolation forcing plus ocean feedback) remains a strengthened monsoon. The impact of ocean feedbacks on the South American and southern African monsoons is relatively small, and therefore these regions, especially the South America, experienced a reduced monsoon regime compared to present. However, there is a strong ocean feedback on the northern Australian monsoon that negates the direct effects of orbital changes and results in a strengthening of austral summer monsoon precipitation in this region. A new synthesis is made for mid-Holocene paleoenvironmental records and is compared with the model simulations. Overall, model simulations produce changes in regional climates that are generally consistent with paleoenvironmental observations.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

We used Little Ice Age (LIA) trimlines and moraines to assess changes in South American glaciers over the last ∼140 years. We determined the extent and length of 640 glaciers during the LIA (∼ AD 1870) and 626 glaciers (the remainder having entirely disappeared) in 1986, 2001 and 2011. The calculated reduction in glacierized area between the LIA and 2011 is 4131 km2 (15.4%), with 660 km2 (14.2%) being lost from the Northern Patagonia Icefield (NPI), 1643 km2 (11.4%) from the Southern Patagonia Icefield (SPI) and 306 km2 (14.4%) from Cordillera Darwin. Latitude, size and terminal environment (calving or land-terminating) exert the greatest control on rates of shrinkage. Small, northerly, land-terminating glaciers shrank fastest. Annual rates of area loss increased dramatically after 2001 for mountain glaciers north of 52° S and the large icefields, with the NPI and SPI now shrinking at 9.4 km2 a–1 (0.23% a–1) and 20.5 km2 a–1 (0.15% a–1) respectively. The shrinkage of glaciers between 52° S and 54° S accelerated after 1986, and rates of shrinkage from 1986 to 2011 remained steady. Icefield outlet glaciers, isolated glaciers and ice caps south of 54° S shrank faster from 1986 to 2001 than they did from 2001 to 2011.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

How and when the Americas were populated remains contentious. Using ancient and modern genome-wide data, we found that the ancestors of all present-day Native Americans, including Athabascans and Amerindians, entered the Americas as a single migration wave from Siberia no earlier than 23 thousand years ago (ka) and after no more than an 8000-year isolation period in Beringia. After their arrival to the Americas, ancestral Native Americans diversified into two basal genetic branches around 13 ka, one that is now dispersed across North and South America and the other restricted to North America. Subsequent gene flow resulted in some Native Americans sharing ancestry with present-day East Asians (including Siberians) and, more distantly, Australo-Melanesians. Putative “Paleoamerican” relict populations, including the historical Mexican Pericúes and South American Fuego-Patagonians, are not directly related to modern Australo-Melanesians as suggested by the Paleoamerican Model.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

South American seasonally-dry tropical forests (SDTF) are critically endangered, with only a small proportion of their original distribution remaining. This paper presents a 12,000 year reconstruction of climate change, fire and vegetation dynamics in the Bolivian Chiquitano SDTF, based upon pollen and charcoal analysis, to examine the resilience of this ecosystem to drought and fire. Our analysis demonstrates a complex relationship between climate, fire and floristic composition over multi-millennial time scales, and reveals that moisture variability is the dominant control upon community turnover in this ecosystem. Maximum drought during the early Holocene, consistent with regional drought reconstructions, correlates with a period of significant fire activity between 8,000 and 7,000 cal yr BP which resulted in a decrease in SDTF diversity. As fire activity declined, but severe regional droughts persisted through the mid-Holocene, SDTF, including Anadenanthera and Astronium, became firmly established in the Bolivian lowlands. The trend of decreasing fire activity during the last two millennia promotes the idea among forest ecologists that SDTF are threatened by fire. Our analysis shows that the Chiquitano seasonally dry biome has been more resilient to Holocene changes in climate and fire regime than previously assumed, but raises questions over whether this resilience will continue in the future under increased temperatures and drought coupled with a higher frequency anthropogenic fire regime.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The phylogeography of South American lineages is a topic of heated debate. Although a single process is unlikely to describe entire ecosystems, related species, which incur similar habitat limitations, can inform the history for a subsection of assemblages. We compared the phylogeographic patterns of the cytochrome oxidase I marker from Anopheles triannulatus (N = 72) and previous results for A. darlingi (N = 126) in a broad portion of their South American distributions. Both species share similar population subdivisions, with aggregations northeast of the Amazon River, in southern coastal Brazil and 2 regions in central Brazil. The average (ST) between these groups was 0.39 for A. triannulatus. Populations northeast of the Amazon and in southeastern Brazil are generally reciprocally monophyletic to the remaining groups. Based on these initial analyses, we constructed the a priori hypothesis that the Amazon and regions of high declivity pose geographic barriers to dispersal in these taxa. Mantel tests confirmed that these areas block gene flow for more than 1000 km for both species. The efficacy of these impediments was tested using landscape genetics, which could not reject our a priori hypothesis but did reject simpler scenarios. Results form summary statistics and phylogenetics suggest that both lineages originated in central Amazonia (south of the Amazon River) during the late Pleistocene (579 000 years ago) and that they followed the same paths of expansion into their contemporary distributions. These results may have implications for other species sharing similar ecological limitations but probably are not applicable as a general paradigm of Neotropical biogeography.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Extensive population structuring is known to occur in Anopheles darlingi, the primary malaria vector of the Neotropics. We analysed the phylogeographic structure of the species using the mitochondrial cytochrome oxidase I marker. Diversity is divided into six main population groups in South America: Colombia, central Amazonia, southern Brazil, south-eastern Brazil, and two groups in north-east Brazil. The ancestral distribution of the taxon is hypothesized to be central Amazonia, and there is evidence of expansion from this region during the late Pleistocene. The expansion was not a homogeneous front, however, with at least four subgroups being formed due to geographic barriers. As the species spread, populations became isolated from each other by the Amazon River and the coastal mountain ranges of south-eastern Brazil and the Andes. Analyses incorporating distances around these barriers suggest that the entire South American range of An. darlingi is at mutation-dispersal-drift equilibrium. Because the species is distributed throughout such a broad area, the limited dispersal across some landscape types promotes differentiation between otherwise proximate populations. Moreover, samples from the An. darlingi holotype location in Rio de Janeiro State are substantially derived from all other populations, implying that there may be additional genetic differences of epidemiological relevance. The results obtained contribute to our understanding of gene flow in this species and allow the formulation of human mosquito health protocols in light of the potential population differences in vector capacity or tolerance to control strategies. (C) 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 97, 854-866.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The objective of this paper is to summarise epidemiological information about the distribution of dental caries among Indigenous peoples in Brazil. The authors also present a case study of a specific group of Xavante Indians, one of the most numerous of Brazil`s Indigenous peoples, describing how their oral health has deteriorated over recent decades, and showing how an oral health programme is attempting to reverse the present trend of increase in caries. The programme at Etenheritipa Xavante village incorporated three principal components: educational, preventive, and clinical. From the beginning, the programme included epidemiological record keeping for monitoring the level of caries in the population. Transversal studies of the condition of oral health among the Xavante of Etenheritipa were undertaken in 1999, 2004, and 2007. In the period from 2004 to 2007 the DMFS values in the 11-15 age cohort had a significant reduction in caries experience. The mean DMFS score fell from 4.95 in 2004 to 2.39 in 2007 (p<0.01). An increase in the percent of individuals who were free from caries was also noted: in 1999, 20% of adolescents 11-15 had no caries; in 2007, the proportion had risen to 47%. The Xavante case is a prime example of the transition in oral health that is taking place among the Indigenous peoples of the Americas, and it highlights the importance of oral health promotion through preventive measures such as access to fluoridation and basic care in reducing the inequality between Indians and non-Indians.