155 research outputs found
Colorful invasion in permissive Neotropical ecosystems: establishment of ornamental non-native poeciliids of the genera Poecilia/Xiphophorus (Cyprinodontiformes: Poeciliidae) and management alternatives
Dry and Humid Periods Reconstructed from Tree Rings in the Former Territory of Sogdiana (Central Asia) and Their Socio-economic Consequences over the Last Millennium
One of the richest societies along the Silk Road developed in Sogdiana,
located in present-day Tajikistan, Uzbekistan, and Kyrgyzstan. This urban civilisation
reached its greatest prosperity during the golden age of the Silk Road (sixth to
ninth century ce). Rapid political and economic changes, accelerated by climatic
variations, were observed during last millennium in this region. The newly developed
tree-ring-based reconstruction of precipitation for the pastmillennium revealed
a series of dry and wet stages. During the Medieval Climate Anomaly (MCA), two
dry periods occurred (900–1000 and 1200–1250), interrupted by a phase of wetter
conditions. Distinct dry periods occurred around 1510–1650, 1750–1850, and
1920–1970, respectively. The juniper tree-ring record of moisture changes revealed
that major dry and pluvial episodes were consistent with those indicated by hydroclimatic
proxy data from adjacent areas. These climate fluctuations have had longand
short term consequences for human history in the territory of former Sogdiana
Pathogenic Huntingtin Repeat Expansions in Patients with Frontotemporal Dementia and Amyotrophic Lateral Sclerosis.
We examined the role of repeat expansions in the pathogenesis of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) by analyzing whole-genome sequence data from 2,442 FTD/ALS patients, 2,599 Lewy body dementia (LBD) patients, and 3,158 neurologically healthy subjects. Pathogenic expansions (range, 40-64 CAG repeats) in the huntingtin (HTT) gene were found in three (0.12%) patients diagnosed with pure FTD/ALS syndromes but were not present in the LBD or healthy cohorts. We replicated our findings in an independent collection of 3,674 FTD/ALS patients. Postmortem evaluations of two patients revealed the classical TDP-43 pathology of FTD/ALS, as well as huntingtin-positive, ubiquitin-positive aggregates in the frontal cortex. The neostriatal atrophy that pathologically defines Huntington's disease was absent in both cases. Our findings reveal an etiological relationship between HTT repeat expansions and FTD/ALS syndromes and indicate that genetic screening of FTD/ALS patients for HTT repeat expansions should be considered
Hydromechanical constraints on piping failure of landslide dams: an experimental investigation
Tree species diversity and utilities in a contracting lowland hillside rainforest fragment in Central Vietnam
Abstract Background Within the highly bio-diverse ‘Northern Vietnam Lowland Rain Forests Ecoregion’ only small, and mostly highly modified forestlands persist within vast exotic-species plantations. The aim of this study was to elucidate vegetation patterns of a secondary hillside rainforest remnant (elevation 120–330 m, 76 ha) as an outcome of natural processes, and anthropogenic processes linked to changing forest values. Methods In the rainforest remnant tree species and various bio-physical parameters (relating to soils and terrain) were surveyed on forty 20 m × 20 m sized plots. The forest's vegetation patterns and tree diversity were analysed using dendrograms, canonical correspondence analysis, and other statistical tools. Results Forest tree species richness was high (172 in the survey, 94 per hectare), including many endemic species (>16%; some recently described). Vegetation patterns and diversity were largely explained by topography, with colline/sub-montane species present mainly along hillside ridges, and lowland/humid-tropical species predominant on lower slopes. Scarcity of high-value timber species reflected past logging, whereas abundance of light-demanding species, and species valued for fruits, provided evidence of human-aided forest restoration and ‘enrichment’ in terms of useful trees. Exhaustion of sought-after forest products, and decreasing appreciation of non-wood products concurred with further encroachment of exotic plantations in between 2010 and 2015. Regeneration of rare tree species was reduced probably due to forest isolation. Conclusions Despite long-term anthropogenic influences, remnant forests in the lowlands of Vietnam can harbor high plant biodiversity, including many endangered species. Various successive future changes (vanishing species, generalist dominance, and associated forest structural-qualitative changes) are, however, expected to occur in small forest fragments. Lowland forest biodiversity can only be maintained if forest fragments maintain a certain size and/or are connected via corridors to larger forest networks. Preservation of the forests may be fostered using new economic incentive schemes
Impacts of artificial reservoirs on floristic diversity and plant functional traits in dry forests after 15 years
Rapid changes in tree composition and biodiversity: consequences of dams on dry seasonal forests
Ecosystem approach for natural hazard mitigation of volcanic tephra in Iceland: building resilience and sustainability
Intrastorm Fluctuations of Piezometric Head and Soil Temperature within a Steep Forested Hollow
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