Ecology and power in the periphery of Maasina : the case of the Hayre in the nineteenth century

This article explores political tensions between successive nineteenth-century rulers of the inland delta of the Niger in central Mali (the Fulbe Diina of Hamdullahi and the Futanke successors of al-Hajj Umar) and the pastoral interests of the Fulbe chiefdoms on their eastern periphery, in a region known as the Hayre. A close study of changing forms of local governance and natural resource management demonstrates that although different strategies were employed by the Fulbe and Futanke states to control the Hayre, the internal dynamics of the region can only partly be explained by the influence of these central powers

The social cognition of medical knowledge, with special reference to childhood epilepsy

This paper arose out of an engagement in medical communication courses at a Gulf university. It deploys a theoretical framework derived from a (critical) sociocognitive approach to discourse analysis in order to investigate three aspects of medical discourse relating to childhood epilepsy: the cognitive processes that are entailed in relating different types of medical knowledge to their communicative context; the types of medical knowledge that are constituted in the three different text types analysed; and the relationship between these different types of medical knowledge and the discursive features of each text type. The paper argues that there is a cognitive dimension to the human experience of understanding and talking about one specialized from of medical knowledge. It recommends that texts be studied in medical communication courses not just in terms of their discrete formal features but also critically, in terms of the knowledge which they produce, transmit and reproduce

Atomic quasi-Bragg diffraction in a magnetic field

We report on a new technique to split an atomic beam coherently with an easily adjustable splitting angle. In our experiment metastable helium atoms in the |{1s2s}^3S_1 M=1> state diffract from a polarization gradient light field formed by counterpropagating \sigma^+ and \sigma^- polarized laser beams in the presence of a homogeneous magnetic field. In the near-adiabatic regime, energy conservation allows the resonant exchange between magnetic energy and kinetic energy. As a consequence, symmetric diffraction of |M=0> or |M=-1> atoms in a single order is achieved, where the order can be chosen freely by tuning the magnetic field. We present experimental results up to 6th order diffraction (24 \hbar k momentum splitting, i.e., 2.21 m/s in transverse velocity) and present a simple theoretical model that stresses the similarity with conventional Bragg scattering. The resulting device constitutes a flexible, adjustable, large-angle, three-way coherent atomic beam splitter with many potential applications in atom optics and atom interferometry.Comment: 4 pages, 5 figure

On the counterfactual nature of gambling near-misses: An experimental study

Research on gambling near-misses has shown that objectively-equivalent outcomes can yield divergent emotional and motivational responses. The subjective processing of gambling outcomes is affected substantially by close but non-obtained outcomes (i.e. counterfactuals). In the current paper, we investigate how different types of near-misses influence self-perceived luck and subsequent betting behavior in a wheel-of-fortune task. We investigate the counterfactual mechanism of these effects by testing the relationship with a second task measuring regret/relief processing. Across two experiments (Experiment 1, $\textit{n}$ = 51; Experiment 2, $\textit{n}$ = 104), we demonstrate that near-wins (neutral outcomes that a reclose to a jackpot) decreased self-perceived luck, whereas near-losses (neutral outcomes that are close to a major penalty) increased luck ratings. The effects of near-misses varied by near-miss position (i.e. whether the spinner stopped just short of, or passed through, the counterfactual outcome), consistent with established distinctions between upward versus downward, and additive versus subtractive, counterfactual thinking. In Experiment 1, individuals who showed stronger counterfactual processing on the regret/relief task were more responsive to near-wins and near-losses on the wheel-of-fortune task. The effect of near-miss position was attenuated when the anticipatory phase (i.e. the spin and deceleration) was removed in Experiment 2. Further differences were observed within the objective gains and losses, between “clear” and “narrow” outcomes. Taken together, these results help substantiate the counterfactual mechanism of near-misses.This work was completed within the University of Cambridge Behavioural and Clinical Neuroscience Institute (director: TW Robbins), supported by a consortium award from the Medical Research Council (MRC Ref G1000183) and Wellcome Trust (WT Ref 093875/Z/10/Z). YW was supported by Shenzhen University Research Fund (701/00036973), National Natural Science Foundation of China (31600923, 31271088) and the Treherne Studentship in Biological Sciences from Downing College, Cambridge. The Centre for Gambling Research at UBC (LC) is supported by funding from the British Columbia Lottery Corporation and the Province of British Columbia

A bumpy train ride: A field experiment on insult, culture of honor, and emotional reactions

The present research examined the relationship between adherence to honor norms and emotional reactions after an insult. Participants were 42 Dutch male train travelers, half of whom were insulted by a confederate who bumped into the participant and made a degrading remark. Compared with insulted participants with a weak adherence to honor norms, insulted participants with a strong adherence to honor norms were (a) more angry, (b) less joyful, (c) less fearful, and (d) less resigned. Moreover, insulted participants with a strong adherence to honor norms perceived more anger in subsequent stimuli than not-insulted participants with a strong adherence to these norms. The present findings support a direct relationship among insult, adherence to honor norms, and emotional reactions. © 2007 American Psychological Association

Computational Screening of Tip and Stalk Cell Behavior Proposes a Role for Apelin Signaling in Sprout Progression

Angiogenesis involves the formation of new blood vessels by sprouting or splitting of existing blood vessels. During sprouting, a highly motile type of endothelial cell, called the tip cell, migrates from the blood vessels followed by stalk cells, an endothelial cell type that forms the body of the sprout. To get more insight into how tip cells contribute to angiogenesis, we extended an existing computational model of vascular network formation based on the cellular Potts model with tip and stalk differentiation, without making a priori assumptions about the differences between tip cells and stalk cells. To predict potential differences, we looked for parameter values that make tip cells (a) move to the sprout tip, and (b) change the morphology of the angiogenic networks. The screening predicted that if tip cells respond less effectively to an endothelial chemoattractant than stalk cells, they move to the tips of the sprouts, which impacts the morphology of the networks. A comparison of this model prediction with genes expressed differentially in tip and stalk cells revealed that the endothelial chemoattractant Apelin and its receptor APJ may match the model prediction. To test the model prediction we inhibited Apelin signaling in our model and in an \emph{in vitro} model of angiogenic sprouting, and found that in both cases inhibition of Apelin or of its receptor APJ reduces sprouting. Based on the prediction of the computational model, we propose that the differential expression of Apelin and APJ yields a "self-generated" gradient mechanisms that accelerates the extension of the sprout.Comment: 48 pages, 10 figures, 8 supplementary figures. Accepted for publication in PLoS ON