Éditeur(s) : London: The Tourist Office London: The Tourist Office
Résumé : Deals with the role of the Baptist Missionary Society during the 1832 insurrection.
(Funding) Support for the development of the technical infrastructure and partner training provided by the United States Department of Education TICFIA program.

Droits : All rights reserved by the source institution.
972.9203 Ja Kni

Éditeur(s) : HAL CCSD Landes Bioscience
Résumé : International audience
In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
Autophagy

hal-00735751
https://hal.archives-ouvertes.fr/hal-00735751
PUBMED : 22966490

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
ISSN: 1354-1013

hal-01080954
https://hal-agroparistech.archives-ouvertes.fr/hal-01080954
DOI : 10.1111/j.1365-2486.2007.01439.x

Éditeur(s) : HAL CCSD European Geosciences Union
Résumé : International audience
Measurements of branch xylem density, D_x, were made for 1466 trees representing 503 species, sampled from 80 sites across the Amazon basin. Measured values ranged from 240 kg m^?3 for a Brosimum parinarioides from Tapajos in West Pará, Brazil to 1130 kg m^?3 for an Aiouea sp. from Caxiuana, Central Pará, Brazil. Analysis of variance showed significant differences in average D_x across the sample plots as well as significant differences between families, genera and species. A partitioning of the total variance in the dataset showed that geographic location and plot accounted for 33% of the variation with species identity accounting for an additional 27%; the remaining "residual" 40% of the variance accounted for by tree to tree (within species) variation. Variations in plot means, were, however, hardly accountable at all by differences in species composition. Rather, it would seem that variations of xylem density at plot level must be explained by the effects of soils and/or climate. This conclusion is supported by the observation that the xylem density of the more widely distributed species varied systematically from plot to plot. Thus, as well as having a genetic component branch xylem density is a plastic trait that, for any given species, varies according to where the tree is growing and in a predictable manner. Exceptions to this general rule may be some pioneers belonging to Pourouma and Miconia and some species within the genera Brosimum, Rinorea and Trichillia which seem to be more constrained in terms of this plasticity than most species sampled as part of this study.
ISSN: 1810-6277

hal-00298004
https://hal.archives-ouvertes.fr/hal-00298004
https://hal.archives-ouvertes.fr/hal-00298004/document
https://hal.archives-ouvertes.fr/hal-00298004/file/bgd-5-2003-2008.pdf

Éditeur(s) : HAL CCSD
Résumé : Atmospheric carbon dioxide records indicate that the land surface has acted as a strong global carbon sink over recent decades, with a substantial fraction of this sink probably located in the tropics, particularly in the Amazon. Nevertheless, it is unclear how the terrestrial carbon sink will evolve as climate and atmospheric composition continue to change. Here we analyse the historical evolution of the biomass dynamics of the Amazon rainforest over three decades using a distributed network of 321 plots. While this analysis confirms that Amazon forests have acted as a long-term net biomass sink, we find a long-term decreasing trend of carbon accumulation. Rates of net increase in above-ground biomass declined by one-third during the past decade compared to the 1990s. This is a consequence of growth rate increases levelling off recently, while biomass mortality persistently increased throughout, leading to a shortening of carbon residence times. Potential drivers for the mortality increase include greater climate variability, and feedbacks of faster growth on mortality, resulting in shortened tree longevity. The observed decline of the Amazon sink diverges markedly from the recent increase in terrestrial carbon uptake at the global scale, and is contrary to expectations based on models.
ISSN: 1476-4687

hal-01204223
https://hal.archives-ouvertes.fr/hal-01204223
DOI : 10.1038/nature14283
PRODINRA : 294797
PUBMED : 25788097

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The ∼55 km-long Firouzkuh fault is located in the Central Alborz Mountains of Iran. It is a left-lateral fault, which dips to the south, and possesses a small dip-slip component of motion that we interpret to result from extension. The ratio of horizontal to vertical displacement across the fault, calculated from the cumulative displacement of landscape features, is 7.6. We provide constraints on the timing of the last earthquake on the Firouzkuh fault from two trenches (T1 and T2) across the fault zone, excavated in 2004, and located east of Firouzkuh city. The trenches expose faulted sedimentary deposits. Two optically-stimulated luminescence (OSL) ages from sediments in the lower part of trench T1 date from the late Pleistocene (15.9 ± 0.9 ka and 27.1 ± 1.7 ka). The younger of the two dated units in T1 is displaced vertically across the fault by 2.2–4.4 m, from which we estimate a strike-slip displacement of 18.2–33.4 m, and hence a average horizontal slip-rate of 1.1–2.2 mm/yr. The sediments exposed in T1 do not yield constraints on the most recent earthquake history. In trench T2, however, human skeletal remains of a middle aged male, which yield a radiocarbon age of 1159 ± 28 BP (corresponding to a mean calendar age of 791 AD), were found within a faulted alluvial layer at a depth of 60–70 cm from the surface. The existence of these medieval human places shows that a surface-rupturing earthquake occurred at some time after 1159 ± 28 BP. The amount of slip in each earthquake on the Firouzkuh fault is difficult to estimate, but assuming the entire ∼55 km fault length ruptures in each event, they will have had a maximum magnitude of 7.1. At our estimated late Quaternary slip-rate of ∼1.1–2.2 mm/yr magnitude 7.1 earthquakes, involving ∼1.2 m average displacement, would be expected to occur every ∼1100–540 years. As the last earthquake on the Firouzkuh fault may be up to ∼700 years in age we suggest that the Firouzkuh fault is a major hazard for earthquakes in the near future.
ISSN: 0743-9547

hal-01122835
https://hal.archives-ouvertes.fr/hal-01122835
DOI : 10.1016/j.jseaes.2013.12.018

Éditeur(s) : HAL CCSD Wiley-Blackwell Wiley
Résumé : A new record from the heart of the Moroccan Middle Atlas cedar forests spans the last 18 000 years and provides valuable insight into our understanding of the natural vegetation and environmental changes. The approach is based on the study of pollen content, geochemical elements and grain size analysis. The pollen data indicate that the vegetation was dominated by herbaceous plants until 9000 BP. Such open landscape allowed greater soil erosion and an input of chemical elements from the watershed. After 9000 BP, tree cover, mainly oak, increased slightly and was accompanied by a higher taxonomic diversity. However, several steppe elements remain well represented in the area until 5000 BP, which suggests that the climate was rather dry during the first part of the Holocene. After 6000 BP, the climate became more favourable to expansion of the forest ecosystems, including Cedrus atlantica, thereby reducing erosion. A strong reduction of the tree pollen percentages is recorded after 2000 BP, which may be related to increasing human activities during the Roman period. These forest changes are concomitant with an increase of lead and copper concentrations in the record, probably related to Roman metalworking activities.
ISSN: 0267-8179

hal-01122848
https://hal.archives-ouvertes.fr/hal-01122848
DOI : 10.1002/jqs.2708