Population genetics of abnormal haemoglobins in Burkina Faso, West Africa

Les fréquences géniques des hémoglobines A (HbA), HbS et HbC, ont été étudiées au Burkina-Faso (BF) ainsi que dans une région avoisinante du Niger : Ayorou. La fréquence d'HbS est plus élevée dans le Sahel (Nord du BF et Ayorou) que dans la zone de savane. L'inverse est trouvé pour HbC. Les résultats essentiels de ce travail sont : (a) la confirmation d'un pic de la fréquence génique de HbC dans le centre du BF (plateau Mossi); (b) une corrélation négative entre les fréquences de HbS et HbC. Cavalli-Sforza et Bodmer ont observé que cette corrélation atteint une intensité significativement différente de celle qui est attendue, par suite de la relation allélique entre HbS et HbC; (c) la comparaison de ces résultats avec les données rassemblées par Livingstone montre une modification de la valeur sélective des différents génotypes au cours des dernières années. Les individus AS ont une valeur sélective plus basse et les AA et SS en ont une plus haute. Nos données sont favorables à l'hypothèse du relâchement partiel de la sélection dans cette région. (Résumé d'auteur

Transmission tree of the highly pathogenic avian influenza (H5N1) epidemic in Israel, 2015

The transmission tree of the Israeli 2015 epidemic of highly pathogenic avian influenza (H5N1) was modelled by combining the spatio-temporal distribution of the outbreaks and the genetic distance between virus isolates. The most likely successions of transmission events were determined and transmission parameters were estimated. It was found that the median infectious pressure exerted at 1 km was 1.59 times (95% CI 1.04, 6.01) and 3.54 times (95% CI 1.09, 131.75) higher than that exerted at 2 and 5 km, respectively, and that three farms were responsible for all seven transmission events. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13567-016-0393-2) contains supplementary material, which is available to authorized users

Harmonic moment dynamics in Laplacian growth

Harmonic moments are integrals of integer powers of z = x+iy over a domain. Here the domain is an exterior of a bubble of air growing in an oil layer between two horizontal closely spaced plates. Harmonic moments are a natural basis for such Laplacian growth phenomena because, unlike other representations, these moments linearize the zero surface tension problem (Richardson, 1972), so that all moments except the lowest one are conserved in time. For non-zero surface tension, we show that the the harmonic moments decay in time rather than exhibiting the divergences of other representations. Our laboratory observations confirm the theoretical predictions and demonstrate that an interface dynamics description in terms of harmonic moments is physically realizable and robust. In addition, by extending the theory to include surface tension, we obtain from measurements of the time evolution of the harmonic moments a value for the surface tension that is within 20% of the accepted value.Comment: 10 pages, 7 figure

The Saffman-Taylor problem on a sphere

The Saffman-Taylor problem addresses the morphological instability of an interface separating two immiscible, viscous fluids when they move in a narrow gap between two flat parallel plates (Hele-Shaw cell). In this work, we extend the classic Saffman-Taylor situation, by considering the flow between two curved, closely spaced, concentric spheres (spherical Hele-Shaw cell). We derive the mode-coupling differential equation for the interface perturbation amplitudes and study both linear and nonlinear flow regimes. The effect of the spherical cell (positive) spatial curvature on the shape of the interfacial patterns is investigated. We show that stability properties of the fluid-fluid interface are sensitive to the curvature of the surface. In particular, it is found that positive spatial curvature inhibits finger tip-splitting. Hele-Shaw flow on weakly negative, curved surfaces is briefly discussed.Comment: 26 pages, 4 figures, RevTex, accepted for publication in Phys. Rev.

Negotiating the inhuman: Bakhtin, materiality and the instrumentalization of climate change

The article argues that the work of literary theorist Mikhail M. Bakhtin presents a starting point for thinking about the instrumentalization of climate change. Bakhtin’s conceptualization of human–world relationships, encapsulated in the concept of ‘cosmic terror’, places a strong focus on our perception of the ‘inhuman’. Suggesting a link between the perceived alienness and instability of the world and in the exploitation of the resulting fear of change by political and religious forces, Bakhtin asserts that the latter can only be resisted if our desire for a false stability in the world is overcome. The key to this overcoming of fear, for him, lies in recognizing and confronting the worldly relations of the human body. This consciousness represents the beginning of one’s ‘deautomatization’ from following established patterns of reactions to predicted or real changes. In the vein of several theorists and artists of his time who explored similar ‘deautomatization’ strategies – examples include Shklovsky’s ‘ostranenie’, Brecht’s ‘Verfremdung’, Artaud’s emotional ‘cruelty’ and Bataille’s ‘base materialism’ – Bakhtin proposes a more playful and widely accessible experimentation to deconstruct our ‘habitual picture of the world’. Experimentation is envisioned to take place across the material and the textual to increase possibilities for action. Through engaging with Bakhtin’s ideas, this article seeks to draw attention to relations between the imagination of the world and political agency, and the need to include these relations in our own experiments with creating climate change awareness

What is consumption, where has it been going, and does it still matter?

This article considers the relationships between consumption, the environment, and wider sociological endeavour. The current vogue for applying theories of practice to the policy domain of ‘sustainable consumption’ has been generative of conceptual renewal, however the field now sits closer to the applied environmental social sciences than to the sociology of consumption. The analysis proceeds via a close reading of the intellectual currents that have given rise to this situation, and it identifies a number of interrelated issues concerning conceptual slippage and the exclusion of core disciplinary concerns. Accordingly a more suitable definition of consumption is offered, an agenda for re-engaging with foundational approaches to consumer culture is established, and a renewal and reorientation of critique is proposed. Working through and building on the contributions of practice theoretical repertoires, this article suggests that consumption scholarship offers a distinctive set of resources to discussions of current ecological crises and uncertain social futures. These are briefly described and the conclusion argues that consumption still matters