321 research outputs found

    CR1 Knops blood group alleles are not associated with severe malaria in the Gambia

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    The Knops blood group antigen erythrocyte polymorphisms have been associated with reduced falciparum malaria-based in vitro rosette formation (putative malaria virulence factor). Having previously identified single-nucleotide polymorphisms (SNPs) in the human complement receptor 1 (CR1/CD35) gene underlying the Knops antithetical antigens Sl1/Sl2 and McC(a)/McC(b), we have now performed genotype comparisons to test associations between these two molecular variants and severe malaria in West African children living in the Gambia. While SNPs associated with Sl:2 and McC(b+) were equally distributed among malaria-infected children with severe malaria and control children not infected with malaria parasites, high allele frequencies for Sl 2 (0.800, 1,365/1,706) and McC(b) (0.385, 658/1706) were observed. Further, when compared to the Sl 1/McC(a) allele observed in all populations, the African Sl 2/McC(b) allele appears to have evolved as a result of positive selection (modified Nei-Gojobori test Ka-Ks/s.e.=1.77, P-value <0.05). Given the role of CR1 in host defense, our findings suggest that Sl 2 and McC(b) have arisen to confer a selective advantage against infectious disease that, in view of these case-control study data, was not solely Plasmodium falciparum malaria. Factors underlying the lack of association between Sl 2 and McC(b) with severe malaria may involve variation in CR1 expression levels

    When the ends outweigh the means: mood and level of identification in depression.

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    Journal ArticleResearch Support, Non-U.S. Gov'tCopyright © 2011 Psychology Press, an imprint of the Taylor & Francis Group, an Informa businessResearch in healthy controls has found that mood influences cognitive processing via level of action identification: happy moods are associated with global and abstract processing; sad moods are associated with local and concrete processing. However, this pattern seems inconsistent with the high level of abstract processing observed in depressed patients, leading Watkins (2008, 2010) to hypothesise that the association between mood and level of goal/action identification is impaired in depression. We tested this hypothesis by measuring level of identification on the Behavioural Identification Form after happy and sad mood inductions in never-depressed controls and currently depressed patients. Participants used increasingly concrete action identifications as they became sadder and less happy, but this effect was moderated by depression status. Consistent with Watkins' (2008) hypothesis, increases in sad mood and decreases in happiness were associated with shifts towards the use of more concrete action identifications in never-depressed individuals, but not in depressed patients. These findings suggest that the putatively adaptive association between mood and level of identification is impaired in major depression

    Processing mode causally influences emotional reactivity: distinct effects of abstract versus concrete construal on emotional response.

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    addresses: Mood Disorders Centre, School of Psychology, University of Exeter, UK. [email protected]: PMCID: PMC2672048types: Journal Article; Research Support, Non-U.S. Gov'tThis is a postprint of an article published in Emotion © 2008 copyright American Psychological Association. 'This article may not exactly replicate the final version published in the APA journal. It is not the copy of record.' Emotion is available online at: http://www.apa.org/pubs/journals/emo/index.aspxThree studies are reported showing that emotional responses to stress can be modified by systematic prior practice in adopting particular processing modes. Participants were induced to think about positive and negative scenarios in a mode either characteristic of or inconsistent with the abstract-evaluative mind-set observed in depressive rumination, via explicit instructions (Experiments 1 and 2) and via implicit induction of interpretative biases (Experiment 3), before being exposed to a failure experience. In all three studies, participants trained into the mode antithetical to depressive rumination demonstrated less emotional reactivity following failure than participants trained into the mode consistent with depressive rumination. These findings provide evidence consistent with the hypothesis that processing mode modifies emotional reactivity and support the processing-mode theory of rumination

    Exploring effects of response biases in affect induction procedures

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    This study examined whether self-reports or ratings of experienced affect, often used as manipulation checks on the efficacy of affect induction procedures (AIPs), reflect genuine changes in affective states rather than response biases arising from demand characteristics or social desirability effects. In a between-participants design, participants were exposed to positive, negative and neutral images with valence-congruent music or sound to induce happy, sad and neutral mood. Half of the participants had to actively appraise each image whereas the other half viewed images passively. We hypothesised that if ratings of affective valence are subject to response biases then they should reflect the target mood in the same way for active appraisal and passive exposure as participants encountered the same affective stimuli in both conditions. We also tested whether the AIP resulted in mood-congruent changes in facial expressions analysed by FaceReader to see whether behavioural indicators corroborate the self-reports. The results showed that while participants’ ratings reflected the induced target valence, the difference between positive and negative AIP was significantly attenuated in the active appraisal condition, suggesting that self-reports of mood experienced after the AIP are not entirely a reflection of response biases. However, there were no effects of the AIP on FaceReader valence scores, in line with theories questioning the existence of cross-culturally and inter-individually universal behavioural indicators of affective states. Efficacy of AIPs is therefore best checked using self-reports

    Isolating the impacts of anthropogenic water use within the hydrological regime of north India

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    The effects of anthropogenic water use play a significant role in determining the hydrological cycle of north India. This paper explores anthropogenic impacts within the region's hydrological regime by explicitly including observed human water use behaviour, irrigation infrastructure and the natural environment in the CHANSE (Coupled Human And Natural Systems Environment) socio‐hydrological modelling framework. The model is constrained by observed qualitative and quantitative information collected in the study area, along with climate and socio‐economic variables from additional sources. Four separate scenarios, including business as usual (BAU, representing observed irrigation practices), groundwater irrigation only (where the influence of the canal network is removed), canal irrigation only (where all irrigation water is supplied by diverted surface water) and rainfed only (where all human interventions are removed) are used. Under BAU conditions the modelling framework closely matched observed groundwater levels. Following the removal of the canal network, which forces farmers to rely completely on groundwater for irrigation, water levels decrease, while under a canal‐only scenario flooding occurs. Under the rainfed‐only scenario, groundwater levels similar to current business‐as‐usual conditions are observed, despite much larger volumes of recharge and discharge entering and leaving the system under BAU practices. While groundwater abstraction alone may lead to aquifer depletion, the conjunctive use of surface and groundwater resources, which includes unintended contributions of canal leakage, create conditions similar to those where no human interventions are present. Here, the importance of suitable water management practices, in maintaining sustainable water resources, is shown. This may include augmenting groundwater resources through managed aquifer recharge and reducing the impacts on aquifer resources through occasional canal water use where possible. The importance of optimal water management practices that highlight trade‐offs between environmental impact and human wellbeing are shown, providing useful information for policy makers, water managers and user

    The following article appeared in S

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    The binding energies of the p-, m-, and o-difluorobenzene-H 2 O complexes have been measured by velocity map ion imaging to be 922Ϯ 10, 945Ϯ 10, and 891Ϯ 4 cm −1 , respectively. The lack of variation provides circumstantial evidence for water binding to the three isomers via the same interaction, viz. an in-plane O-H¯F hydrogen bond to one of the fluorine atoms on the ring, with a second, weaker interaction of the water O atom with an ortho hydrogen, as determined previously for the p-difluorobenzene-H 2 O complex ͓Kang et al., J. Phys. Chem. A 109, 767 ͑2005͔͒. The ground state binding energies for the difluorobenzene-H 2 O complexes are ϳ5 % -11% larger than that for benzene-H 2 O, where binding occurs to the electrons out-of-plane. However, in the S 1 state the binding energies of the o-and p-difluorobenzene-H 2 O complexes are smaller than the benzene-H 2 O value, raising an interesting question about whether the geometry at the global energy minimum remains in-plane in the excited electronic states of these two complexes. Recoil energy distributions for dissociation of p-difluorobenzene-H 2 O have been measured from the 3 1 , 5 2 , and 3 1 5 1 levels of the excited electronic state. These levels are 490, 880, and 1304 cm −1 , respectively, above the dissociation threshold. Within the experimental uncertainty, the recoil energy distributions are the same for dissociation from these three states, with average recoil energies of ϳ100 cm −1 . These recoil energies are 60% larger than was observed for the dissociation of p-difluorobenzene-Ar, which is a substantially smaller increase than the 400% seen in a comparable study of dissociation within the triplet state for pyrazine-Ar, -H 2 O complexes. The majority of the available energy is partitioned into vibration and rotation of the fragments

    Is it possible to detect planets around young active G and K dwarfs?

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    Theoretical predictions suggest that the distribution of planets in very young stars could be very different to that typically observed in Gyr old systems that are the current focus of radial velocity surveys. However, the detection of planets around young stars is hampered by the increased stellar activity associated with young stars, the signatures of which can bias the detection of planets. In this paper, we place realistic limitations on the possibilities for detecting planets around young active G and K dwarfs. The models of stellar activity based on tomographic imaging of the G dwarf HD 141943 and the K1 dwarf AB Dor also include contributions from plage and many small random starspots. Our results show that the increased stellar activity levels present on young solar-type stars strongly impacts the detection of Earth-mass and Jupiter-mass planets and that the degree of activity jitter is directly correlated with stellar v sin i. We also show that for G and K dwarfs, the distribution of activity in individual stars is more important than the differences in induced radial velocities as a function of spectral type. We conclude that Jupiter-mass planets can be detected close-in around fast-rotating young active stars, Neptune-mass planets around moderate rotators and that Super-Earths are only detectable around very slowly rotating stars. The effects of an increase in stellar activity jitter by observing younger stars can be compensated for by extending the observational base-line to at least 100 epochs.Peer reviewe
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