Pulmonary-artery pressure and exhaled nitric oxide in Bolivian and Caucasian high altitude dwellers

There is evidence that high altitude populations may be better protected from hypoxic pulmonary hypertension than low altitude natives, but the underlying mechanism is incompletely understood. In Tibetans, increased pulmonary respiratory NO synthesis attenuates hypoxic pulmonary hypertension. It has been speculated that this mechanism may represent a generalized high altitude adaptation pattern, but direct evidence for this speculation is lacking. We therefore measured systolic pulmonary-artery pressure (Doppler chocardiography) and exhaled nitric oxide (NO) in 34 healthy, middle-aged Bolivian high altitude natives and in 34 age- and sex-matched, well-acclimatized Caucasian low altitude natives living at high altitude (3600 m). The mean+/-SD systolic right ventricular to right atrial pressure gradient (24.3+/-5.9 vs. 24.7+/-4.9 mmHg) and exhaled NO (19.2+/-7.2 vs. 22.5+/-9.5 ppb) were similar in Bolivians and Caucasians. There was no relationship between pulmonary-artery pressure and respiratory NO in the two groups. These findings provide no evidence that Bolivian high altitude natives are better protected from hypoxic pulmonary hypertension than Caucasian low altitude natives and suggest that attenuation of pulmonary hypertension by increased respiratory NO synthesis may not represent a universal adaptation pattern in highaltitude populations.

Geomorphological and sedimentary evidence for late Pleistocene to Holocene hydrological change along the Río Mamoré, Bolivian Amazon

Aerial photography and satellite imagery reveal manifold geomorphological evidence of a dynamic evolution of past and present rivers in the Bolivian Amazon. Comparison of oxbow lake and meander scar dimensions along an inactive meander belt of the Río Mamoré (Llanos de Moxos, north-eastern Bolivia) and its modern counterpart suggests significant regional paleohydrological variability. We used these features as geomorphological and sedimentary archives to enhance our understanding of longer-term variations of the fluvial system. Late Pleistocene to Holocene hydrological changes of the Río Mamoré are inferred from: (i) the analysis of satellite imagery, (ii) discharge estimates from meander morphology, (iii) stratigraphic, and (iv) chronological information based on luminescence and radiocarbon dating. The combined data from three oxbows indicate that the now abandoned meander belt – the paleo-Mamoré – continued to be active at least until ∼5 ka, and likely even postdating 3 ka. An up to threefold increase in discharge is estimated for the modern Río Mamoré versus the paleo-Mamoré. The altered runoff regime may have triggered an avulsive shift towards the currently active Río Mamoré. The preceding increase in discharge in turn, was possibly related to a shift in climatic conditions, which changed markedly between the mid- and late Holocene in tropical South America. In addition, it may have been the indirect result of capturing the avulsive Río Grande system to the east of the Río Mamoré. Alternative explanations for the differences in dimensions of the paleo versus the modern Río Mamoré, i.e. contemporaneous activity of both rivers or alteration of site factors such as the channel/floodplain relationship, are considered to be unlikely.

On the road through the Bolivian Amazon: a multi-level land governance analysis of deforestation

Previous studies have shown that collective property rights offer higher flexibility than individual property and improve sustainable community-based forest management. Our case study, carried out in the Beni department of Bolivia, does not contradict this assertion, but shows that collective rights have been granted in areas where ecological contexts and market facilities were less favourable to intensive land use. Previous experiences suggest investigating political processes in order to understand the criteria according to which access rights were distributed. Based on remote sensing and on a multi-level land governance framework, our research confirms that land placed under collective rights, compared to individual property, is less affected by deforestation among Andean settlements. However, analysis of the historical process of land distribution in the area shows that the distribution of property rights is the result of a political process based on economic, spatial, and environmental strategies that are defined by multiple stakeholders. Collective titles were established in the more remote areas and distributed to communities with lower productive potentialities. Land rights are thus a secondary factor of forest cover change which results from diverse political compromises based on population distribution, accessibility, environmental perceptions, and expected production or extraction incomes.

Productive Diversification and Sustainable Use of Complex Social-Ecological Systems: A Comparative Study of Indigenous and Settler Communities in the Bolivian Amazon

Agricultural and forest productive diversification depends on multiple socioeconomic drivers—like knowledge, migration, productive capacity, and market—that shape productive strategies and influence their ecological impacts. Our comparison of indigenous and settlers allows a better understanding of how societies develop different diversification strategies in similar ecological contexts and how the related socioeconomic aspects of diversification are associated with land cover change. Our results suggest that although indigenous people cause less deforestation and diversify more, diversification is not a direct driver of deforestation reduction. A multidimensional approach linking sociocognitive, economic, and ecological patterns of diversification helps explain this contradiction.

Post-immigration education of adult immigrants in Switzerland

In 2000, 20 per cent of the Swiss resident population was constituted by foreigners (Fibbi and Wanner 2009). As in other European countries, the migrant population in Switzerland can broadly be differentiated into three groups: 1) Migrant groups from less-developed regions with substantially lower educational attainments and an increased risk for unemployment than in the reference population, 2) Migrant groups that are rather more successful, although still somewhat behind the majority population, 3) Migrant groups who even outperform the majority population in terms of educational and employment success (Heath et al. 2008). Given these inequalities – in particular in the first migrant group – participation in further education in the country of destination might contribute to better integrate migrants in the Swiss society in general and the labour market in particular. On the basis of the pooled SAKE data set (1991-2000), patterns of participation in further education of adult migrants are analysed. As the results show, many migrant groups differ from the Swiss reference population regarding participation in further education. While inequalities are often explained by educational attainments and occupational status, in some cases they hold even if controlled for the determinants explaining participation in further education in general. Regarding migrant-specific determinants, type of residence permit proved to be an important indicator explaining the disadvantages in access to further education encountered by migrants originating from Former Yugoslavia.