Wicked social–ecological problems forcing unprecedented change on the latitudinal margins of coral reefs: the case of southwest Madagascar

High-latitude coral reefs may be a refuge and area of reef expansion under climate change. As these locations are expected to become dryer and as livestock and agricultural yields decline, coastal populations may become increasingly dependent on marine resources. To evaluate this social–ecological conundrum, we examined the Grand Récif of Toliara (GRT), southwest Madagascar, which was intensively studied in the 1960s and has been highly degraded since the 1980s. We analyzed the social and ecological published and unpublished literature on this region and provide new data to assess the magnitude of the changes and evaluate the causes of reef degradation. Top-down controls were identified as the major drivers: human population growth and migrations, overfishing, and climate change, specifically decreased rainfall and rising temperature. Water quality has not changed since originally studied, and bottom-up control was ruled out. The identified network of social–ecological processes acting at different scales implies that decision makers will face complex problems that are linked to broader social, economic, and policy issues. This characterizes wicked problems, which are often dealt with by partial solutions that are exploratory and include inputs from various stakeholders along with information sharing, knowledge synthesis, and trust building. A hybrid approach based on classical fishery management options and preferences, along with monitoring, feedback and forums for searching solutions, could move the process of adaptation forward once an adaptive and appropriately scaled governance system is functioning. This approach has broad implications for resources management given the emerging climate change and multiple social and environmental stresses

APOBEC3A Is a Specific Inhibitor of the Early Phases of HIV-1 Infection in Myeloid Cells

Myeloid cells play numerous roles in HIV-1 pathogenesis serving as a vehicle for viral spread and as a viral reservoir. Yet, cells of this lineage generally resist HIV-1 infection when compared to cells of other lineages, a phenomenon particularly acute during the early phases of infection. Here, we explore the role of APOBEC3A on these steps. APOBEC3A is a member of the APOBEC3 family that is highly expressed in myeloid cells, but so far lacks a known antiviral effect against retroviruses. Using ectopic expression of APOBEC3A in established cell lines and specific silencing in primary macrophages and dendritic cells, we demonstrate that the pool of APOBEC3A in target cells inhibits the early phases of HIV-1 infection and the spread of replication-competent R5-tropic HIV-1, specifically in cells of myeloid origins. In these cells, APOBEC3A affects the amount of vDNA synthesized over the course of infection. The susceptibility to the antiviral effect of APOBEC3A is conserved among primate lentiviruses, although the viral protein Vpx coded by members of the SIVSM/HIV-2 lineage provides partial protection from APOBEC3A during infection. Our results indicate that APOBEC3A is a previously unrecognized antiviral factor that targets primate lentiviruses specifically in myeloid cells and that acts during the early phases of infection directly in target cells. The findings presented here open up new venues on the role of APOBEC3A during HIV infection and pathogenesis, on the role of the cellular context in the regulation of the antiviral activities of members of the APOBEC3 family and more generally on the natural functions of APOBEC3A

ASSOCIATION D'UNE POLYMYOSITE, D'UNE INSULINO-RESISTANCE DE TYPE B ET D'UN ACANTHOSIS NIGRICANS (A PROPOS D'UNE OBSERVATION)

LILLE2-BU Santé-Recherche (593502101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

La sclérodermie systémique en Martinique (étude rétrospective à propos de 39 cas)

LIMOGES-BU Médecine pharmacie (870852108) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Facteurs limitant la productivité phytoplanctonique dans 49 petits barrages

Introduction Le nord de la Côte d'Ivoire est caractérisé par un climat relativement humide (1 200 mm par an), mais avec des périodes très sèches qui alternent avec des périodes de fortes précipitations. Le contrôle de l'eau à des fins d'intensification des activités agricoles et pastorales y est apparu comme une nécessité. Plusieurs centaines de petites retenues d'eau (surface 1 km2) souvent formées à partir d'une digue barrant un bas-fond ont ainsi été créées au cours des dernières décennie..

Métabolisme bactérien et phytoplanctonique de trois petits barrages de Côte d'Ivoire

Introduction L'un des axes de recherche du programme Petits Barrages dans sa composante limnologique est, en relation avec les différents facteurs agissant sur les écosystèmes, l'identification des éléments structuraux et fonctionnels qui en expliquent la productivité (Cecchi, 1998). Tout écosystème, d'une façon générale, est en équilibre entre l'homogénéité et l'hétérogénéité (Legendre et Troussellier, 1993) et cela sous la pression de trois forces : exogènes, comme les énergies auxiliaires,..

Trophic coupling between bacterial and phytoplanktonic compartments in shallow tropical reservoirs (Ivory Coast, West Africa)

Biomass and production of bacterial and phytoplanktonic communities were measured during diurnal cycles at different stations in 3 shallow tropical reservoirs (Ivory Coast). Investigations were conducted in 1995 during 2 typical hydrological seasons (dry season in March and following rainy season in December). Bacterial production in the plankton ranged from 1.2 to 26.2 microg C/l/h and bacterial biomass ranged from 11 to 163 microg C/l. A slope of 0.625 (n = 93) for the regression of log-transformed bacterial biomass versus log-transformed production suggests that the bacteria were strongly controlled by bottom-up processes. Ratios between net primary production and bacterial production averaged 67% (range 38 to 140%), indicating that the reservoirs studied can be considered as meso-eutrophic ecosystems. Average bacterial carbon demand corresponded to 97% of the net primary production, suggesting that the biological systems studied are based on autotrophic metabolism. These relationships are the result of a close metabolic coupling between bacterioplankton and phytoplankton, with a large fraction of primary production routed through heterotrophic bacteria and the microbial loop. (Résumé d'auteur

Polystyrene Tribological Performance: Progress in the Understanding of Polymers Attrition during Chemical Engineering Processes

International audienceThe issue of polymers films and particles friction, damage and attrition attracts both scientific and technological interest. In fact, polymers friction and attrition are of pivotal importance in many technological domains and applications such as powder technology, processes in fluidized beds, materials handling and transport processing (e.g., screw, pneumatic and hydraulic convey) and biopolymers and polymers processing. Moreover, polymer damage (e.g., attrition) has harmful effects on product quality, on environmental and health safety (source of toxic dust) and on the process reliability because of changes in particle properties such as particle shape and size distribution. The present contribution will focus on the attrition analysis induced by the rub of hemispherical polystyrene particles against smooth and functionalized silicon walls. Several experimental and structural factors affecting attrition of polymeric particles such as the velocity, the applied normal force, polymer molecular weights, and the wall surface energy are discussed. A homemade device was used to carry out a single slide of the polystyrene hemispherical (4 nm radius) particle onto different silicon walls. Atomic force microscopy (AFM) was used so as to analyze the attrition appearance induced by the polymer damage. Nano-friction experiments were also achieved by AFM in lateral mode in order to distinguish the effect of interfacial interactions at the nanometric scale

Increased proviral load in HTLV-1-infected patients with rheumatoid arthritis or connective tissue disease.

BACKGROUND: Human T-lymphotropic virus type 1 (HTLV-1) proviral load is related to the development of HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and has also been shown to be elevated in the peripheral blood in HTLV-1-infected patients with uveitis or alveolitis. Increased proliferation of HTLV-1-infected cells in, or migration of such cells into, the central nervous system is also seen in HAM/TSP. In the present study, we evaluated the proviral load in a cohort of HTLV-1-infected patients with arthritic conditions. RESULTS: HTLV-1 proviral load in the peripheral blood from 12 patients with RA and 6 patients with connective tissue disease was significantly higher than that in matched asymptomatic HTLV-1 carriers, but similar to that in matched HAM/TSP controls. HAM/TSP was seen in one-third of the HTLV-1-infected patients with RA or connective tissue disease, but did not account for the higher proviral load compared to the asymptomatic carrier group. The proviral load was increased in the synovial fluid and tissue from an HTLV-1-infected patient with RA, the values suggesting that the majority of infiltrated cells were HTLV-1-infected. In the peripheral blood from HTLV-1-infected patients with RA or connective tissue disease, HTLV-1 proviral load correlated with the percentages of memory CD4+ T cells and activated T cells, and these percentages were shown to be markedly higher in the synovial fluid than in the peripheral blood in an HTLV-1-infected patient with RA. CONCLUSIONS: These biological findings are consistent with a role of the retrovirus in the development of arthritis in HTLV-1-infected patients. A high level of HTLV-1-infected lymphocytes in the peripheral blood and their accumulation in situ might play a central role in the pathogenesis of HTLV-1-associated inflammatory disorders. Alternatively, the autoimmune arthritis, its etiological factors or treatments might secondarily enhance HTLV-1 proviral load