La pêche crevettière en Côte d'Ivoire. Bilan 1969-1970 et perspectives

The evolution of the fishery of the pink shrimp Penaeus duorarum Burkenroad is analysed from its beginning in 1969 until the end of 1970. A rapid and general decline of the yield has been evident during this period. The actual shrimp fleet seems to be too big to allow an exploitation economically convenient of the stock

Adhesion and non-linear rheology of adhesives with supramolecular crosslinking points

Soft supramolecular materials are promising for the design of innovative and highly tunable adhesives. These materials are composed of polymer chains functionalized by strongly interacting moieties, sometimes called "stickers". In order to systematically investigate the effect of the presence of associative groups on the debonding properties of a supramolecular adhesive, a series of supramolecular model systems has been characterized by probe-tack tests. These model materials, composed of linear and low dispersity poly(butylacrylate) chains functionalized in the middle by a single tri-urea sticker, are able to self-associate by six hydrogen bonds and range in molecular weight (M n) between 5 and 85 kg/mol. The linear rheology and the nanostructure of the same materials (called "PnBA3U") was the object of a previous study 1,2. At room temperature, the association of polymers via hydrogen bonds induces the formation of rod-like aggregates structured into bundles for M n \textless{} 40kg/mol and the behavior of a soft elastic material was observed (G'\textgreater{}\textgreater{}G "and G'~$\omega$ 0). For higher M n , the filaments were randomly oriented and polymers displayed a crossover towards viscous behavior although terminal relaxation was not reached in the experimental frequency window. All these materials show however similar adhesive properties characterized by a cohesive mode of failure and low debonding energies (W adh \textless{}40J/m 2 for a debonding speed of 100$\mu$m/s). The debonding mechanisms observed during the adhesion tests have been investigated in detail with an Image tools analysis developed by our group 3. The measure of the projected area covered by cavities growing in the adhesive layer during debonding can be used to estimate the true stress in the walls of the cavities and thus, to characterize the in-situ large strain deformation of the thin layer during the adhesion test itself. This analysis revealed in particular that the PnBA3U materials with M n \textless{} 40 kg/mol soften very markedly at large deformation like yield stress fluids, explaining the low adhesion energies measured for these viscoelastic gels.

Determining Crack Aperture Distribution in Rocks Using the C-14-PMMA Autoradiographic Method : Experiments and Simulations

Because cracks control the global mechanical and transport properties of crystalline rocks, it is of a crucial importance to suitably determine their aperture distribution, which evolves through alteration processes and rock weathering. Due to the high variability of crack networks in rocks, a multiscale approach is needed. The C-14-PMMA (polymethylmethacrylate) method was developed to determine crack apertures using a set of artificial crack samples with different controlled apertures and tilt angles and also using Monte Carlo simulations. The experiments and simulations show the same result: the estimation of apparent aperture w(A) was successful regardless of tilt angle, even if the estimates are less accurate for low tilt angles (Peer reviewe

Using historical fisheries data to predict tuna distribution within the British Indian Ocean Territory marine protected area, and implications for its management

1. Recently, several large marine protected areas (MPAs) have been established globally and it is hoped that they will aid the recovery of populations of highly-mobile, large pelagic species. Understanding the distribution of these species within MPAs is key to delivering effective management but monitoring can be challenging over such vast areas of open ocean. 2. Historical fisheries data, collected prior to reserve establishment, can provide an insight into the past distributions of target species. We investigated the 10spatial and temporal distribution of yellowfin (Thunnus albacares) and skipjack (Katsuwonus pelamis) tuna catch using logbook data from the purse seine fishery in British Indian Ocean Territory (BIOT) from 1996 to 2010, before it was established as an MPA in April 2010. 3. Generalized additive models (GAMs) were used to predict tuna presence and relative abundance from fishing records in relation to temporal and environmental variables. Significant variables included sea salinity, temperature and water velocity. 4. Predictions from the models identified a distinct hotspot for large yellowfin tuna within the MPA, and areas of high predicted relative abundance of skipjack tuna. We recommend that these areas are used as focal points from which populations can be monitored and investigations into tuna residency time can occur, so that the effectiveness of the MPA in conserving highly-mobile pelagic fish can be determined

Monitoring Antigen Processing for MHC Presentation via Macroautophagy

Macroautophagy has recently emerged as an important catabolic process involved not only in innate immunity but also in adaptive immunity. Initially described to deliver intracellular antigens to MHC class II loading compartments, its molecular machinery has now also been described to impact the delivery of extracellular antigens to MHC class II loading compartments through the noncanonical use of the macroautophagy machinery during LC3-associated phagocytosis (LAP). Therefore, in pathological situations (viral or bacterial infections, tumorigenesis) the pathway might be involved in shaping CD4$^{+}$ T cell responses.In this chapter we describe three basic experiments for the monitoring and manipulation of macroautophagic antigen processing toward MHC class II presentation through the canonical pathway. Firstly, we will discuss how to monitor autophagic flux and autophagosome fusion with MHC class II loading compartments. Secondly, we will show how to target proteins to autophagosomes in order to monitor macroautophagy dependent antigen processing via their enhanced presentation on MHC class II molecules to CD4$^{+}$ T cells. And finally, we will describe how macroautophagy can be silenced in antigen presenting cells, like human monocyte-derived dendritic cells (DCs)

Electrical Brain Responses in Language-Impaired Children Reveal Grammar-Specific Deficits

Background: Scientific and public fascination with human language have included intensive scrutiny of language disorders as a new window onto the biological foundations of language and its evolutionary origins. Specific language impairment (SLI), which affects over 7% of children, is one such disorder. SLI has received robust scientific attention, in part because of its recent linkage to a specific gene and loci on chromosomes and in part because of the prevailing question regarding the scope of its language impairment: Does the disorder impact the general ability to segment and process language or a specific ability to compute grammar? Here we provide novel electrophysiological data showing a domain-specific deficit within the grammar of language that has been hitherto undetectable through behavioural data alone. Methods and Findings: We presented participants with Grammatical(G)-SLI, age-matched controls, and younger child and adult controls, with questions containing syntactic violations and sentences containing semantic violations. Electrophysiological brain responses revealed a selective impairment to only neural circuitry that is specific to grammatical processing in G-SLI. Furthermore, the participants with G-SLI appeared to be partially compensating for their syntactic deficit by using neural circuitry associated with semantic processing and all non-grammar-specific and low-level auditory neural responses were normal. Conclusions: The findings indicate that grammatical neural circuitry underlying language is a developmentally unique system in the functional architecture of the brain, and this complex higher cognitive system can be selectively impaired. The findings advance fundamental understanding about how cognitive systems develop and all human language is represented and processed in the brain

Connected by sea, disconnected by tuna? Challenges to regionalism in the Southwest Indian Ocean

Madagascar, Mauritius and Seychelles are at the center of industrial tuna extraction in the Southwest Indian Ocean (SWIO). In this paper, we show that, while a discourse of regionalism between the three islands is prominent, the possibilities of regionalism face deep challenges in relation to the tuna industry. This is due to three factors. First, local perceptions, especially amongst those working in and on the tuna industry, are in disconnection with an ‘Indianoceania’ vision. Second, the geopolitics between coastal states and distant water fishing nations create various entanglements including through fishing access revenue and foreign aid. Finally, the materiality of tuna can at times create competition as countries seek to individually maximize benefits from the industry. We argue that the active reinforcement of regional identity and collaboration around this resource is necessary to sustain local benefits into the future

Tuna Longline Fishing around West and Central Pacific Seamounts

BACKGROUND: Seamounts have been identified as aggregating locations for pelagic biodiversity including tuna; however the topography and prevailing oceanography differ between seamounts and not all are important for tuna. Although a relatively common feature in oceanic ecosystems, little information is available that identifies those that are biologically important. Improved knowledge offers opportunities for unique management of these areas, which may advance the sustainable management of oceanic resources. In this study, we evaluate the existence of an association between seamounts and tuna longline fisheries at the ocean basin scale, identify significant seamounts for tuna in the western and central Pacific Ocean, and quantify the seamount contribution to the tuna longline catch. METHODOLOGY/PRINCIPAL FINDINGS: We use data collected for the Western and Central Pacific Ocean for bigeye, yellowfin, and albacore tuna at the ocean basin scale. GLMs were applied to a coupled dataset of longline fisheries catch and effort, and seamount location information. The analyses show that seamounts may be associated with an annual longline combined catch of 35 thousand tonnes, with higher catch apparent for yellowfin, bigeye, and albacore tuna on 17%, 14%, and 14% of seamounts respectively. In contrast 14%, 18%, and 20% of seamounts had significantly lower catches for yellowfin, bigeye and albacore tuna respectively. Studying catch data in relation to seamount positions presents several challenges such as bias in location of seamounts, or lack of spatial resolution of fisheries data. Whilst we recognize these limitations the criteria used for detecting significant seamounts were conservative and the error in identification is likely to be low albeit unknown. CONCLUSIONS/SIGNIFICANCE: Seamounts throughout the study area were found to either enhance or reduce tuna catch. This indicates that management of seamounts is important Pacific-wide, but management approaches must take account of local conditions. Management of tuna and biodiversity resources in the region would benefit from considering such effects

An Investigation to Validate the Grammar and Phonology Screening (GAPS) Test to Identify Children with Specific Language Impairment

The extraordinarily high incidence of grammatical language impairments in developmental disorders suggests that this uniquely human cognitive function is "fragile". Yet our understanding of the neurobiology of grammatical impairments is limited. Furthermore, there is no "gold-standard" to identify grammatical impairments and routine screening is not undertaken. An accurate screening test to identify grammatical abilities would serve the research, health and education communities, further our understanding of developmental disorders, and identify children who need remediation, many of whom are currently un-diagnosed. A potential realistic screening tool that could be widely administered is the Grammar and Phonology Screening (GAPS) test--a 10 minute test that can be administered by professionals and non-professionals alike. Here we provide a further step in evaluating the validity and accuracy (sensitivity and specificity) of the GAPS test in identifying children who have Specific Language Impairment (SLI)

Impact of HIV on Cell Survival and Antiviral Activity of Plasmacytoid Dendritic Cells

Plasmacytoid dendritic cells (pDCs) are important mediators of innate immunity that act mainly through secretion of interferon (IFN)-α. Previous studies have found that these cells can suppress HIV in vitro; additionally, pDCs have been shown to be severely reduced in the peripheral blood of HIV-infected individuals. In the present study, we sought to determine the ability of pDCs to directly suppress viral replication ex vivo and to delineate the potential mechanisms whereby pDCs are depleted in HIV-infected individuals. We demonstrate that activated pDCs strongly suppress HIV replication in autologous CD4(+) T cells via a mechanism involving IFN-α as well as other antiviral factors. Of note, unstimulated pDCs from infected individuals who maintain low levels of plasma viremia without antiretroviral therapy were able to suppress HIV ex vivo via a mechanism requiring cell-to-cell contact. Our data also demonstrate that death of pDCs by both apoptosis and necrosis is induced by fusion of HIV with pDCs. Taken together, our data suggest that pDCs play an important role in the control of HIV replication and that high levels of viral replication in vivo are associated with pDC cell death via apoptosis and necrosis. Elucidation of the mechanism by which pDCs suppress HIV replication in vivo may have clinically relevant implications for future therapeutic strategies