L'arachide au Sénégal : un moteur en panne

L'arachide, qui a été le moteur du développement de l'économie sénégalaise jusqu'au milieu des années 1970, en fournissant la majeure partie des revenus en milieu rural et en assurant 80 % des exportations, a connu un recul important cette dernière décennie. Cette crise rappelle celle qu'ont connue les pays voisins, il y a une vingtaine d'années, et qui a conduit à la disparition de cette culture. Inquiet de cette situation, le gouvernement du Sénégal a demandé à une équipe du Cirad de déterminer les raisons de la désaffection des paysans envers l'arachide, afin de pouvoir y remédier et relancer la production. Cet ouvrage est le résultat des travaux de cette équipe. Il montre que, contrairement aux idées selon lesquelles la crise de l'arachide serait principalement une crise de l'approvisionnement des huileries, avec un repli des producteurs sur le marché informel, on assiste à une 'grève' des producteurs. Par une méthodologie originale de recensement, les auteurs démontrent que la production a été longtemps surestimée. L'enquête auprès des producteurs explique la chute des rendements par la dégradation des facteurs de production (baisse de la fertilité des sols, diminution de la qualité des semences), par la disparition des services agricoles, par une politique du prix d'achat de l'arachide qui décourage les producteurs. Relancer la production de l'arachide ne suffit plus, il faut aussi prendre en compte les potentialités agricoles du pays, chercher à mieux valoriser les autres productions et tracer une politique d'appui en milieu paysan

Exceptional sperm cooperation in the wood mouse

Spermatozoa from a single male will compete for fertilization of ova with spermatozoa from another male when present in the female reproductive tract at the same time. Close genetic relatedness predisposes individuals towards altruism, and as haploid germ cells of an ejaculate will have genotypic similarity of 50%, it is predicted that spermatozoa may display cooperation and altruism to gain an advantage when inter-male sperm competition is intense. We report here the probable altruistic behaviour of spermatozoa in an eutherian mammal. Spermatozoa of the common wood mouse, Apodemus sylvaticus, displayed a unique morphological transformation resulting in cooperation in distinctive aggregations or 'trains' of hundreds or thousands of cells, which significantly increased sperm progressive motility. Eventual dispersal of sperm trains was associated with most of the spermatozoa undergoing a premature acrosome reaction. Cells undergoing an acrosome reaction in aggregations remote from the egg are altruistic in that they help sperm transport to the egg but compromise their own fertilizing ability

Building Behind Levees: Public Policy and Housing Prices in the Flood Zone

This paper assesses the market value of protection afforded by levees, using data from two metropolitan areas within California\u27s Central Valley where some levees have been subject to scrutiny since the late 1980s

A systematic review of keys challenges of CO2 transport via pipelines

Transport of carbon dioxide (CO2) via pipeline from the point of capture to a geologically suitable location for either sequestration or enhanced hydrocarbon recovery is a vital aspect of the carbon capture and storage (CCS) chain. This means of CO2 transport has a number of advantages over other means of CO2 transport, such as truck, rail, and ship. Pipelines ensure continuous transport of CO2 from the capture point to the storage site, which is essential to transport the amount of CO2 captured from the source facilities, such as fossil fuel power plants, operating in a continuous manner. Furthermore, using pipelines is regarded as more economical than other means of CO2 transport The greatest challenges of CO2 transport via pipelines are related to integrity, flow assurance, capital and operating costs, and health, safety and environmental factors. Deployment of CCS pipeline projects is based either on point-to-point transport, in which case a specific source matches a specific storage point, or through the development of pipeline networks with a backbone CO2 pipeline. In the latter case, the CO2 streams, which are characterised by a varying impurity level and handled by the individual operators, are linked to the backbone CO2 pipeline for further compression and transport. This may pose some additional challenges. This review involves a systematic evaluation of various challenges that delay the deployment of CO2 pipeline transport and is based on an extensive survey of the literature. It is aimed at confidence-building in the technology and improving economics in the long run. Moreover, the knowledge gaps were identified, including lack of analyses on a holistic assessment of component impurities, corrosion consideration at the conceptual stage, the effect of elevation on CO2 dense phase characteristics, permissible water levels in liquefied CO2, and commercial risks associated with project abandonment or cancellation resulting from high project capital and operating costs

Antiinflammatory Therapy with Canakinumab for Atherosclerotic Disease

Background: Experimental and clinical data suggest that reducing inflammation without affecting lipid levels may reduce the risk of cardiovascular disease. Yet, the inflammatory hypothesis of atherothrombosis has remained unproved. Methods: We conducted a randomized, double-blind trial of canakinumab, a therapeutic monoclonal antibody targeting interleukin-1β, involving 10,061 patients with previous myocardial infarction and a high-sensitivity C-reactive protein level of 2 mg or more per liter. The trial compared three doses of canakinumab (50 mg, 150 mg, and 300 mg, administered subcutaneously every 3 months) with placebo. The primary efficacy end point was nonfatal myocardial infarction, nonfatal stroke, or cardiovascular death. RESULTS: At 48 months, the median reduction from baseline in the high-sensitivity C-reactive protein level was 26 percentage points greater in the group that received the 50-mg dose of canakinumab, 37 percentage points greater in the 150-mg group, and 41 percentage points greater in the 300-mg group than in the placebo group. Canakinumab did not reduce lipid levels from baseline. At a median follow-up of 3.7 years, the incidence rate for the primary end point was 4.50 events per 100 person-years in the placebo group, 4.11 events per 100 person-years in the 50-mg group, 3.86 events per 100 person-years in the 150-mg group, and 3.90 events per 100 person-years in the 300-mg group. The hazard ratios as compared with placebo were as follows: in the 50-mg group, 0.93 (95% confidence interval [CI], 0.80 to 1.07; P = 0.30); in the 150-mg group, 0.85 (95% CI, 0.74 to 0.98; P = 0.021); and in the 300-mg group, 0.86 (95% CI, 0.75 to 0.99; P = 0.031). The 150-mg dose, but not the other doses, met the prespecified multiplicity-adjusted threshold for statistical significance for the primary end point and the secondary end point that additionally included hospitalization for unstable angina that led to urgent revascularization (hazard ratio vs. placebo, 0.83; 95% CI, 0.73 to 0.95; P = 0.005). Canakinumab was associated with a higher incidence of fatal infection than was placebo. There was no significant difference in all-cause mortality (hazard ratio for all canakinumab doses vs. placebo, 0.94; 95% CI, 0.83 to 1.06; P = 0.31). Conclusions: Antiinflammatory therapy targeting the interleukin-1β innate immunity pathway with canakinumab at a dose of 150 mg every 3 months led to a significantly lower rate of recurrent cardiovascular events than placebo, independent of lipid-level lowering. (Funded by Novartis; CANTOS ClinicalTrials.gov number, NCT01327846.

Lessons from Mycobacterium avium complex-associated pneumonitis: a case report

ABSTRACT: INTRODUCTION: Mycobacterium avium complex (MAC) is an increasingly recognized cause of pulmonary disease in immunocompetent individuals. An acute form of MAC lung disease, MAC-associated pneumonitis, has generally been associated with the use of hot tubs. There is controversy in the literature about whether MAC-associated pneumonitis is a classic hypersensitivity pneumonitis or is a direct manifestation of mycobacterial infection. CASE PRESENTATION: We report the second case in the literature of MAC-associated pneumonitis not related to the use of hot tubs. The source of MAC in a 52-year-old immunocompetent patient was an intrapulmonary cyst containing numerous acid-fast bacilli. The patient developed disseminated miliary nodules throughout both lung fields. Histological examination of resected lung tissue revealed well-formed, acid-fast negative granulomas composed predominantly of CD4+ T-cells and CD68+ histiocytes. The granulomas were strongly positive for tumor necrosis factor-alpha, a pro-inflammatory cytokine. CONCLUSION: The attempt to classify MAC-associated pneumonitis as either a classic hypersensitivity pneumonitis or a direct manifestation of mycobacterial infection is not particularly useful. Our case demonstrates that MAC-associated pneumonitis is characterized by a vigorous T-helper 1-like, pro-inflammatory, immune response to pulmonary mycobacterial infection. The immunopathology provides a rationale for clinical studies of anti-MAC therapy with the addition of anti-inflammatory agents (for example, corticosteroids) to hasten the resolution of infection and symptoms

Managing water scarcity at a river basin scale with economic instruments

This paper presents a conceptual framework for both assessing the role of economic instruments, and reshaping them in order to enhance their contribution to the goals of managing water scarcity. Water management problems stem from the mismatch between a multitude of individual decisions, on the one hand, and the current and projected status of water resources on the other. Economics can provide valuable incentives that drive individual decisions, and can design efficient instruments to address water governance problems in a context of conflicting interests and relevant transaction costs. Yet, instruments such as water pricing or trading are mostly based on general principles of welfare economics that are not readily applicable to assets as complex as water. A flaw in welfare economic approaches lies in the presumption that economic instruments may be good orbad on their own (e.g., finding the "right" price). This vision changes radically when we focus on the problem, instead of the instrument. In this paper, we examine how economic instruments to achieve welfare-enhancing water resource outcomes can realize their full potential in basin-scale management contexts. We follow a political economy perspective that views conflicts between public and private interest as the main instrumental challenge of water management. Our analysis allows us to better understand the critical importance of economic instruments for reconciling individual actions towards collective ambitions of water efficiency, equity and sustainability with lessons for later-adopting jurisdictions. Rather than providing panaceas, the successful design and implementation of economic instruments as key river basin management arrangements involves high transaction costs, wide institutional changes and collective action at different levels

Disentangling the complexity of groundwater dependent social-ecological systems

Groundwater resources are part of larger social-ecological systems. In this chapter, we review the various dimensions of these complex systems in order to uncover the diversity of elements at stake in the evolution of an aquifer and the loci for possible actions to control its dynamics. Two case studies illustrate how the state of an aquifer is embedded in a web of biophysical and sociopolitical processes. We propose here a holistic view through an IGM-scape that describes the various possible pathways of evolution for a groundwater related social-ecological system. Then we describe the elements of this IGM-scape starting with physical entities and processes, including relations with surface water and quality issues. Interactions with society bring an additional layer of considerations, including decisions on groundwater abstraction, land use changes and even energy related choices. Finally we point out the policy levers for groundwater management and their possible consequences for an aquifer, taking into account the complexity of pathways opened by these levers