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Biodiversity and Conservation - Assessments of the performance of protected-area (PA) networks for aquatic biodiversity conservation are rare yet essential for successful conservation of species....  相似文献   

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The biocultural interchange between the Eastern and Western Hemispheres beginning in the late fifteenth century initiated an unprecedented adaptive transition for Native Americans. This article presents findings from the initial population biological study of contact in the Central Andes of Peru using human skeletal remains. We test the hypothesis that as a consequence of Spanish colonization, the indigenous Mochica population of Mórrope on the north coast of Peru experienced elevated systemic biological stress. Using multivariate statistical methods, we examine childhood stress reflected in the prevalence of linear enamel hypoplasias and porotic hyperostosis, femoral growth velocity, and terminal adult stature. Nonspecific periosteal infection prevalence and D(30+)/D(5+) ratio estimations of female fertility characterized adult systemic stress. Compared to the late pre-Hispanic population, statistically significant patterns of increased porotic hyperostosis and periosteal inflammation, subadult growth faltering, and depressed female fertility indicate elevated postcontact stress among both children and adults in Mórrope. Terminal adult stature was unchanged. A significant decrease in linear enamel hypoplasia prevalence may not indicate improved health, but reflect effects of high-mortality epidemic disease. Various lines of physiological, archaeological, and ethnohistoric evidence point to specific socioeconomic and microenvironmental factors that shaped these outcomes, but the effects of postcontact population aggregation in this colonial town likely played a fundamental role in increased morbidity. These results inform a model of postcontact coastal Andean health outcomes on local and regional scales and contribute to expanding understandings of the diversity of indigenous biological variation in the postcontact Western Hemisphere.  相似文献   

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Using IUCN Red List species as biodiversity surrogates, supplemented with additional analyses based on ecoregional diversity, priority areas for conservation in Mesoamerica, Chocó, and the Tropical Andes were identified using the methods of systematic conservation planning. Species’ ecological niches were modeled from occurrence records using a maximum entropy algorithm. Niche models for 78 species were refined to produce geographical distributions. Areas were prioritized for conservation attention using a complementarity-based algorithm implemented in the ResNet software package. Targets of representation for Red List species were explored from 10 to 90% of the modeled distributions at 10% increments; for the 53 ecoregions, the target was 10% for each ecoregion. Selected areas were widely dispersed across the region, reflecting the widespread distribution of Red List species in Mesoamerica, Chocó, and the Tropical Andes, which underscores the region’s importance for biodiversity. In general, existing protected areas were no more representative of biodiversity than areas outside them. Among the countries in the region, the protected areas of Belize performed best and those of Colombia and Ecuador worst. A high representation target led to the selection of a very large proportion of each country except Colombia and Ecuador (for a 90% target, 83–95% of each country was selected). Since such large proportions of land cannot realistically be set aside as parks or reserves, biodiversity conservation in Mesoamerica, Chocó, and the Tropical Andes will require integrative landscape management which combines human use of the land with securing the persistence of biota. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

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Drawing on ethnographic fieldwork in Turkey’s southern province of Hatay, near the Syrian border, this paper examines the shifts in the positioning of ethnoreligious differences vis-à-vis Turkish nationalism over the past decade. Hatay was annexed to Turkey from French Mandate Syria in 1939, 16 years after the foundation of the Turkish nation-state, and did not experience the national homogenization that characterized the transition from the Ottoman Empire to the Turkish Republic in the post-WWI era. Its ensuing ethnoreligious diversity with a population composed of bilingual (Turkish-Arabic) Jewish, Christian, Alawi, and Sunni communities characterized the region’s peripheral border status until the new millennium. In this paper, I focus on two major shifts in Turkish politics which reoriented the ethnoreligious identities of these communities. First, I interrogate the short-lived turn to pluralism in mid-2000s to late-2000s when Hatay’s religious diversity gained prominence as an exemplar of Turkish Muslim tolerance. Built on the nostalgia for Ottoman cosmopolitanism against Turkey’s Republican model of nationalism, this regime celebrated the ethnoreligious difference of Hatay’s residents as long as they were identified as representable elements of the nation. I then turn my attention to the emergent ruptures in this discourse of multireligious nationalism with the outbreak of the Syrian War, Turkey’s foreign policy, and the arrival of Syrian refugees in Hatay. In showing how both polities operated within and through rather than replaced the formerly hegemonic understandings of national unity, this paper reveals the constant reworking of national and ethnoreligious identities at the Middle Eastern borderlands.  相似文献   

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This paper seeks to explain the historic importance to Catalan nationalism of the nineteenth-century poet and priest, Jacint Verdaguer. In order to do so, rather than focus on his contribution – and that of the wider cultural revival, the Renaixença – to the development of the Catalan language as the basis for national political mobilization, this paper argues that we cannot fully understand Verdaguer's importance without reference to his role in constructing a geographical narrative linking nation and territory. At the same time, given that national meanings are always contested, the paper proposes a dialectical approach to nationalism that situates the work of writers within the context of power struggles between social groups. Consequently, Veradguer's centrality to Catalan nationalism is ultimately explained by his role in producing a geographical narrative capable of attracting important sectors of rural Catalonia to the hegemonic project of the industrial bourgeoisie.  相似文献   

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Cloud forest vegetation structure and composition were studied in the Venezuelan Andes at three sites in Mérida State. Although the sites are within 10 to 30 km of each other, climatic, geologic and topographic differences are remarkable. The main purpose of the study was to determine the relationship of specific environmental variables to forest vegetation characteristics, including basal area, tree height, density and diversity, and leaf area index (LAI). At 51 plots, all trees' diameter at breast height >10 cm were recorded and identified. Although the environment at the three sites is distinctive, the tree species composition of the most abundant species was very similar. None of the measured environment variables were significantly correlated with the measured vegetation structure variables, except LAI, which was correlated with slope orientation; LAI showed higher values at south‐facing plots. Tree height was relatively uniform, while basal area was highly variable and reached very high values. Stem densities were in the range reported elsewhere in cloud forests. Multivariate analysis using structure or composition data shows segregation of the plots by site. Principal component analyses by site indicate a minor impact of environmental factors on forest variables. At each site, a particular group of species are correlated with the ordination axes. We conclude that species pools and forest dynamics add to the complexity of the structure of the studied cloud forests.  相似文献   

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Alzheimer’s disease (AD) is the most common form of neurodegenerative disease. The brain is particularly vulnerable to oxidative damage induced by unregulated redox-active metals such as copper and iron, and the brains of AD patients display evidence of metal dyshomeostasis and increased oxidative stress. The colocalisation of copper and amyloid β (Aβ) in the glutamatergic synapse during NMDA-receptor-mediated neurotransmission provides a microenvironment favouring the abnormal interaction of redox-potent Aβ with copper under conditions of copper dysregulation thought to prevail in the AD brain, resulting in the formation of neurotoxic soluble Aβ oligomers. Interactions between Aβ oligomers and copper can further promote the aggregation of Aβ, which is the core component of extracellular amyloid plaques, a central pathological hallmark of AD. Copper dysregulation is also implicated in the hyperphosphorylation and aggregation of tau, the main component of neurofibrillary tangles, which is also a defining pathological hallmark of AD. Therefore, tight regulation of neuronal copper homeostasis is essential to the integrity of normal brain functions. Therapeutic strategies targeting interactions between Aβ, tau and metals to restore copper and metal homeostasis are discussed.  相似文献   

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Species richness and diversity of Carabidae (Coleoptera), as well as rates of endemicity, are studied along altitudinal transects in the páramo of Ecuadorian Andes, from 3500 to 5000 m. Whereas a global tendency to reduction of species richness is evident from 4200 m upwards, two zones of high diversity and high proportion of endemic species occur at 3800–4000 m and at 4200–4400 m. Species turnover between grass páramo and superpáramo is significantly higher in drier mountains, especially in the Western Cordillera, than in humid mountains of the Eastern Cordillera. The altitudinal range of Carabid species tends globally to decrease along the vertical gradient, but with important local variations due to microenvironmental factors, especially humidity rate. When compared with recent phytogeographical studies, these results tend to support the idea that the majority of tussockgrass páramo is a secondary anthropogenic ecosystem. On the contrary, it is argued that the xeric landscape of the Chimborazo “arenal” is primordial, based on the presence of a stenotopic and possibly relict species, Pelmatellus andium Bates 1891.  相似文献   

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Although strip clear-cutting has a long history of use in the temperate zone, it was only recently introduced for timber extraction in tropical rain forests, where it is known as the Palcazú Forest Management System. In this system heterogeneous tropical forests are managed for native gap-dependent timber species by simulating gap dynamics through clear-cutting long, narrow strips every 40 years. As part of an assessment of the sustainability of this system, we evaluated the recovery of tree basal area, species richness, and composition after 15 years of regeneration on two strips (30 × 150 m) clear-cut in 1989 in Jenaro Herrera, Peru. Timber stocking and the effects of silvicultural thinning were assessed in both strips. The strips recovered 58–73% of their original basal area and 45–68% of their original tree species richness. Although both strips recovered more than 50% of their original composition, commercial species had lower basal areas and lower densities than in the forest before the clearing. Pioneer species with high basal areas remained dominant 15 years after the cutting. Silvicultural thinning in 1996 reduced the abundance of pioneer species in both strips, and increased the abundance of commercial species in one of the strips. Half of one strip was harvested by deferment-cut (only commercial trees >30 cm dbh and “other” species >5 cm dbh were cut); regeneration here had greater abundance of commercial species and lower abundance of pioneer species. The low stocking of commercial trees challenges the sustainability claims for this forest management system.  相似文献   

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Marital isonymy is frequently used to estimate inbreeding and the repeated pairs method is useful to investigate whether the population under examination has subdivisions. These methods can also be applied to registers, such as population censuses, where both spouses' surnames are noted. In this paper, the 1795 census for Córdoba province is analysed. Numerically speaking, Spanish and mixed-race people are the major ethno-social groups in the register. In order to estimate inbreeding, the isonymic method was applied to both groups, at provincial and at parish level. To appreciate to what extent the parishes were genetically isolated, Wright's Fst was also calculated. The repeated pairs method was also used for both groups to assess if population subdivision existed in the units under study. Finally, to evaluate whether the subdivision based on surnames reflected the ethno-social stratification, the same method was used considering the two groups together. At the provincial scale, both groups displayed low inbreeding and micro-differentiation, although the former was higher for the Spanish and the latter for mixed-race groups, which could indicate a more marked conjugal selectivity in the Spanish. At the parish scale, preferences for isonymic spouses were not pronounced either in Spanish or in mixed-race groups; in the Spanish group population subdivision prevailed, with the opposite occurring in the mixed-race group. The estimations from repeated pairs, taking the two groups together, indicated that for the studied populations the surnames do not allow the two groups to be differentiated into isolated reproductive units.  相似文献   

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《Seminars in Virology》1994,5(2):133-145
The incidence of the mosquito-borne flavivirus diseases, yellow fever, dengue and dengue hemorrhagic fever has increased dramatically in recent years. Both diseases are characterized by the emergence of explosive epidemics. Yellow fever outbreaks appear to have a periodicity dependent upon fluctuations in sylvatic (enzootic) transmission cycles and the ecological factors that influence these cycles. Spread of the virus from the sylvatic cycle to human settlements, ultimately with interhuman transmission by domestic Aedes aegypti is a repeating event in Africa, and presents a renewed threat in the Americas, where effective Ae. aegypti control collapsed in the 1970s. The incidence of dengue has also increased dramatically in recent years, with up to 80 million persons living in tropical regions of the world now affected annually—an attack rate of 4%. The severe form, dengue hemorrhagic fever (DHF) has become a leading health problem throughout Asia in the last 20 years and is emerging as an epidemic disease in the Americas. Unlike yellow fever, sylvatic dengue transmission cycles are not responsible for disease emergence. The major factors underlying dengue epidemics are changes in human ecology, increasing contact with Ae. aegypti, the co-circulation of multiple dengue serotypes, and a rising prevalence of immunity and immunopathological events that underlie the pathogenesis of DHF. In this review, the complex interplay of virus, host, vector, environment and weather in the ecology of yellow fever and dengue are explored.  相似文献   

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A report on the family Scrophulariaceae in the páramos of the Venezuelan Andes is made, which includes 13 genera. A key to the genera is provided.  相似文献   

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Wnts comprise a large family of proteins that have shown to be part of a signaling cascade that regulates several aspects of develop- ment including organogenesis, mid brain development as welt as stem cell proliferation. Wnt signaling pathway plays different roles in the development of neuronal circuits and also in the adult brain, where it regulates synaptic transmission and plasticity. It has been also implicated in various diseases including cancer and neurodegenerative diseases, reflecting its relevance in fundamental biological pro- cesses. This review summarizes the progress about Wnts function in mature nervous system with a focus on Alzheimer's disease (AD). We discuss the prospects of modulating canonical and non-canonical Wnt signaling as a strategy for neuroprotection. This will include the potential of Wnts to: (i) act as potent regulators of hippocampai synapses and impact in learning and memory; (ii) regulate adult neurogenesis; and finally (iii) control AD pathogenesis.  相似文献   

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