Are grain markets in Niger driven by speculation?

Over the last two decades, millet prices in Niger have enjoyed periods of spectacular increase during which they seem to go well above their fundamental value. These episodes of price bursts followed by rapid reversals could be attributed to the presence of rational speculative bubbles. Considering millet as a food asset we have developed a pricing model, and tested for the presence of periodically and partially collapsing bubbles for 15 millet markets in Niger. The test strategy consists of estimating the fundamental value of millet and investigating the dynamic properties of price deviations from fundamentals. A battery of unit root tests aimed at controlling for skewness and kurtosis, and for non linearity in the bubble process, is implemented. These tests do not reject the presence of rational bubbles for some of the sample markets, and allow the identification of expanding and collapsing phases in bubble processes. The results show that small markets, located in deficit and remote areas are more prone to speculation than large markets in the main producing and consuming regions.periodically collapsing bubbles, M-TAR, Markov switching ADF, Residual Augmented ADF test, Rolling ADF test, millet

Concepts and Metrics for Climate Change Risk and Development - Towards an index for Climate Resilient Development

The threats posed by climate change are increasingly seen as a major problem for the future of nature and humanity, and significant improvements are needed to set the world on a climate change resilient path to the future. At global, regional and local level there is an increasing demand from both policy makers and the business sector for understanding relationships between the determinants of climate change risk (hazards, exposure, vulnerability, and adaptation) as well as metrics and policy options to deal with such a risk. Meeting this demand is fraught with difficulties due to the multitude of objectives/criteria to be considered as well as the interrelated nature of the determinants of climate change, which are dynamic and evolving over time. A fundamental link between development strategies, climate adaptation planning, and disaster risk reduction has been recognized, but not characterized. In this context, climate resilient development can be indicated as one of the political priorities at global level. This report reviews the main concepts and metrics used to assess and manage climate change risk within an international context, which considers climate resilient development a central issue. It analyses in depth five climate change indices aiming at measuring all or just a few components of climate change risk with a global coverage. The review highlights that there is no consensus on concepts and metrics for a climate change risk index. A joint analysis of these indices identifies a common geography of the hot spot areas for climate change risk and vulnerability. Results show a consensus on the relevance of climate change risk in developing countries. The report highlights some open questions and gaps on conceptual frameworks, metrics, and data to build an index for climate resilient development. It identifies key issues that will be addressed to build a platform towards an index for climate resilient developmentJRC.H.7-Climate Risk Managemen

Impact of climate related shocks on child's health in Burkina Faso

The aim of this paper is to estimate the impact of weather related income shocks on child health in rural Burkina Faso where rain fed agriculture is the dominant production system. We combine health data originating from the 2008 household survey with meteorological data to define shocks at the child level. We first estimate the marginal effect of rainfall at various ages on the child's health in order to identify the critical period during which deprivation has the most severe consequences. Then we look for a different impact of shocks on girls and boys that would reflect a gender bias in intra household resource allocation. We also assess the household ability to smooth consumption by testing for an asymmetric effect of rainfall shocks according to their size and by testing the impact of shocks according to household endowments. Results evidence a strong relationship between rainfall shocks during the prenatal period and child health. Households are not able to dampen small but negative rainfall shocks. Unexpectedly, girls are less severely affected by shocks than boys. The robustness of results is tested by using the sibling and difference-in-differences estimators as well as placebo regressions

Changement climatique, chocs pluviométriques et sécurité alimentaire : essais sur l'usage de l'information climatique en économie du développement

Acknowledging a limited knowledge and use of climate data in development economics, this thesis proposes a new perspective on the use of both macroeconomic and microeconomic climate data. This thesis has a two-Fold objective: to deepen knowledge on climate data through the production of a new global database directly exploitable by economists, and to propose several applications of this database at different economic scales. The first part focuses on the macroeconomic aspect of the climate data. Its aim is to empower researchers with a deeper understanding of global climate data and to increase economic knowledge on the characteristics of climate change. Chapter 1 contains a climate database available monthly over the 1900-2008 period for nearly 200 countries. Based on this initial work, Chapter 2 proposes an original use of the database with the construction of a physical indicator of vulnerability to climate change, a tool which can be used as a basis for the allocation of aid for climate change adaptation. The second part of this thesis is composed of two microeconomic studies whose aim is to analyse the behaviour of agents facing a rainfall shock. In those two chapters, rainfall data is used to compensate for the lack of data on agricultural production. At the household level, Chapter 3 focuses on the implications of an episode of reduced rainfall on the nutritional status of children under five years old. It shows that rural households do not have the capacity to provide for or absorb climate shocks. At the grain market level, Chapter 4 studies the response of prices to a shock front rainfall. It reveals the presence of speculation, especially in small and poorly integrated markets.Partant du constat d’une faible connaissance et d’une utilisation encore limitée des données climatiques en économie du développement, cette thèse propose une exploitation originale à la fois macroéconomique et microéconomique des données climatiques. Elle répond à un double objectif consistant d’une part, à enrichir les connaissances concernant les données climatiques en fournissant une nouvelle base de données mondiale directement exploitable par les économistes, d’autre part, à en proposer des exploitations variées et à différentes échelles de l’économie. La première partie propose une utilisation macroéconomique des données climatiques. Elle doit permettre une meilleure appréhension des données climatiques mondiales, afin d’améliorer des connaissances sur les caractéristiques du changement climatique d’un point de vue économique. Le chapitre 1 produit une base de données climatiques disponible pour près de 200 pays au niveau mensuel pour la période 1900-2008. S’appuyant sur ce premier travail, le chapitre 2 propose une utilisation originale de la base en construisant un indicateur de vulnérabilité physique au changement climatique pouvant servir d’outil pour guider l’allocation de l’aide à l’adaptation au changement climatique. La seconde partie de cette thèse est constituée de deux études microéconomiques dont le but est d’analyser les réactions des agents face à un choc climatique. Dans ces deux chapitres, les données pluviométriques pallient le manque de données concernant la production agricole. Au niveau du ménage agricole d’abord, le chapitre 3 s’intéresse aux conséquences d’un épisode de baisse de la pluviométrie sur l’état nutritionnel des enfants de moins de cinq ans et révèle que les ménages ruraux n’ont pas la capacité d’assurer ou d’absorber ces chocs climatiques. Au niveau d’un marché céréalier ensuite, le chapitre 4 s’attache à étudier la réaction des prix face à un choc pluviométrique et met en évidence la présence d’une spéculation, particulièrement sur des marchés mal intégrés et de petite taille

The geography of poverty and climate extremes

This chapter presents the challenge of reducing extreme poverty under climate change. It argues that climate extremes are the manifestations of climate change most likely to affect poverty over the next 25 years, with impacts on lives, livelihoods and assets impeding efforts to eradicate it

The induction of heme oxygenase 1 decreases contractility in human internal thoracic artery and radial artery grafts

ObjectiveSpasm remains a potential problem encountered during the use of arterial grafts in coronary artery bypass surgery. Heme oxygenase plays a role in the control of arterial vasoreactivity. Heme oxygenase exists in 2 constitutive isoforms (heme oxygenase 2 and 3) and an inducible isoform (heme oxygenase 1). The aim of our study was to induce heme oxygenase 1 by using hemin in human internal thoracic and radial arteries and to evaluate the effect of this induction on the contractility of these arterial grafts.MethodsSegments of human arterial grafts obtained from patients undergoing isolated coronary artery bypass surgery were incubated in organ chambers for 4 hours in the presence of 10−4 mol/L hemin. Concentration-response curves to norepinephrine were obtained in control and hemin-treated arterial rings. Heme oxygenase 1 expression was evaluated by using enzyme-linked immunosorbent assays and immunohistochemical staining.ResultsThe contractility of the arterial rings to norepinephrine was significantly reduced after incubation with hemin. Zinc protoporphyrin (an inhibitor of heme oxygenase) reversed the effect of hemin, whereas the inhibitor of nitric oxide synthase had no effect. The inhibitor of soluble guanylate cyclase blocked the decrease in contractility induced by hemin. Immunohistochemical staining revealed a large expression of heme oxygenase 1 in all vascular layers of hemin-treated internal thoracic artery and radial artery rings. Enzyme-linked immunosorbent assay studies showed a significant increase in heme oxygenase 1 levels in hemin-treated internal thoracic artery and radial artery rings.ConclusionHemin caused in vitro induction of heme oxygenase 1 in human internal thoracic artery and radial artery grafts. This induction resulted in a reduced contractility to norepinephrine, partially through the cyclic guanosine monophosphate–dependent pathway. This effect was independent from nitric oxide synthesis

Private adaptation in semi-arid lands: a tailored approach to ‘leave no one behind’

Globally, semi-arid lands (SALs) are home to approximately one billion people, including some of the poorest and least food secure. These regions will be among the hardest hit by the impacts of climate change. This article urges governments and their development partners to put SAL inhabitants and their activities at the heart of efforts to support adaptation and climate resilient development, identifying opportunities to capitalise on the knowledge, institutions, resources and practices of SAL populations in adaptation action

French Roadmap for complex Systems 2008-2009

This second issue of the French Complex Systems Roadmap is the outcome of the Entretiens de Cargese 2008, an interdisciplinary brainstorming session organized over one week in 2008, jointly by RNSC, ISC-PIF and IXXI. It capitalizes on the first roadmap and gathers contributions of more than 70 scientists from major French institutions. The aim of this roadmap is to foster the coordination of the complex systems community on focused topics and questions, as well as to present contributions and challenges in the complex systems sciences and complexity science to the public, political and industrial spheres

Identification of a BRCA2-Specific modifier locus at 6p24 related to breast cancer risk

Common genetic variants contribute to the observed variation in breast cancer risk for BRCA2 mutation carriers; those known to date have all been found through population-based genome-wide association studies (GWAS). To comprehensively identify breast cancer risk modifying loci for BRCA2 mutation carriers, we conducted a deep replication of an ongoing GWAS discovery study. Using the ranked P-values of the breast cancer associations with the imputed genotype of 1.4 M SNPs, 19,029 SNPs were selected and designed for inclusion on a custom Illumina array that included a total of 211,155 SNPs as part of a multi-consortial project. DNA samples from 3,881 breast cancer affected and 4,330 unaffected BRCA2 mutation carriers from 47 studies belonging to the Consortium of Investigators of Modifiers of BRCA1/2 were genotyped and available for analysis. We replicated previously reported breast cancer susceptibility alleles in these BRCA2 mutation carriers and for several regions (including FGFR2, MAP3K1, CDKN2A/B, and PTHLH) identified SNPs that have stronger evidence of association than those previously published. We also identified a novel susceptibility allele at 6p24 that was inversely associated with risk in BRCA2 mutation carriers (rs9348512; per allele HR = 0.85, 95% CI 0.80-0.90, P = 3.9×10−8). This SNP was not associated with breast cancer risk either in the general population or in BRCA1 mutation carriers. The locus lies within a region containing TFAP2A, which encodes a transcriptional activation protein that interacts with several tumor suppressor genes. This report identifies the first breast cancer risk locus specific to a BRCA2 mutation background. This comprehensive update of novel and previously reported breast cancer susceptibility loci contributes to the establishment of a panel of SNPs that modify breast cancer risk in BRCA2 mutation carriers. This panel may have clinical utility for women with BRCA2 mutations weighing options for medical prevention of breast cancer

An original phylogenetic approach identified mitochondrial haplogroup T1a1 as inversely associated with breast cancer risk in BRCA2 mutation carriers

Introduction: Individuals carrying pathogenic mutations in the BRCA1 and BRCA2 genes have a high lifetime risk of breast cancer. BRCA1 and BRCA2 are involved in DNA double-strand break repair, DNA alterations that can be caused by exposure to reactive oxygen species, a main source of which are mitochondria. Mitochondrial genome variations affect electron transport chain efficiency and reactive oxygen species production. Individuals with different mitochondrial haplogroups differ in their metabolism and sensitivity to oxidative stress. Variability in mitochondrial genetic background can alter reactive oxygen species production, leading to cancer risk. In the present study, we tested the hypothesis that mitochondrial haplogroups modify breast cancer risk in BRCA1/2 mutation carriers. Methods: We genotyped 22,214 (11,421 affected, 10,793 unaffected) mutation carriers belonging to the Consortium of Investigators of Modifiers of BRCA1/2 for 129 mitochondrial polymorphisms using the iCOGS array. Haplogroup inference and association detection were performed using a phylogenetic approach. ALTree was applied to explore the reference mitochondrial evolutionary tree and detect subclades enriched in affected or unaffected individuals. Results: We discovered that subclade T1a1 was depleted in affected BRCA2 mutation carriers compared with the rest of clade T (hazard ratio (HR) = 0.55; 95% confidence interval (CI), 0.34 to 0.88; P = 0.01). Compared with the most frequent haplogroup in the general population (that is, H and T clades), the T1a1 haplogroup has a HR of 0.62 (95% CI, 0.40 to 0.95; P = 0.03). We also identified three potential susceptibility loci, including G13708A/rs28359178, which has demonstrated an inverse association with familial breast cancer risk. Conclusions: This study illustrates how original approaches such as the phylogeny-based method we used can empower classical molecular epidemiological studies aimed at identifying association or risk modification effects.Peer reviewe