759 research outputs found

    Direct and generative retrieval of autobiographical memories: The roles of visual imagery and executive processes.

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    Two experiments used a dual task methodology to investigate the role of visual imagery and executive resources in the retrieval of specific autobiographical memories. In Experiment 1, dynamic visual noise led to a reduction in the number of specific memories retrieved in response to both high and low imageability cues, but did not affect retrieval times. In Experiment 2, irrelevant pictures reduced the number of specific memories but only in response to low imageability cues. Irrelevant pictures also increased response times to both high and low imageability cues. The findings are in line with previous work suggesting that disrupting executive resources may impair generative, but not direct, retrieval of autobiographical memories. In contrast, visual distractor tasks appear to impair access to specific autobiographical memories via both the direct and generative retrieval routes, thereby highlighting the potential role of visual imagery in both pathways

    The influence of mental toughness on responses to feedback in snooker: A real-time examination

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    Two experiments investigated whether mental toughness (MT) is associated with the ability to respond to and/or overcome unwanted information during real-time sport performance. Participants were male snooker players ranging from club to professional level, and MT was measured using the MTQ48 (Clough et al., 2002). In experiment 1, players performed five break-off shots and received deceptive feedback (either positive or negative) from the researcher about their performance relative to other players. Then they performed another five break-offs. Results showed a significant decline in performance following feedback, but no interaction with the nature of feedback or MT variables. In experiment 2, feedback was delivered by a coach and yielded a significant effect on performance. Specifically, negative feedback improved performance while positive feedback impaired performance. The Life Control subscale of the MTQ48 was a significant covariate. The results suggest that negative feedback, delivered constructively by a respected figure, may act as a catalyst for performance enhancement in snooker and that this is moderated by MT

    The Effect of a Brief Mindfulness Intervention on Memory for Positively and Negatively Valenced Stimuli

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    A core component of mindfulness is non-judgmental observation of internal and external stimuli. The present study investigated the effect of mindfulness on memory for emotional stimuli. Participants were exposed to a brief mindfulness intervention and subsequently performed a verbal learning test consisting of positive, neutral, and negative words. Control participants received no intervention and directly performed the verbal learning test. After 20 min, participants recalled as many words as possible. Participants in the mindfulness condition remembered a significantly lower proportion of negative words compared to control participants. No differences between both groups were observed for the proportion of remembered positive words. These findings suggest that memory processes may be a potential mechanism underlying the link between mindfulness and subjective well-being

    Dominance of variant A in Human Herpesvirus 6 viraemia after renal transplantation

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    <p>Abstract</p> <p>Background</p> <p>Human herpesvirus 6 (HHV-6), mostly variant B reactivation in renal transplant patients has been published by other authors, but the pathogenetic role of HHV-6 variant A has not been clarified. Our aims were to examine the prevalence of HHV-6, to determine the variants, and to investigate the interaction between HHV-6 viraemia, human cytomegalovirus (HCMV) infection and clinical symptoms.</p> <p>Methods</p> <p>Variant-specific HHV-6 nested PCR and quantitative real-time PCR were used to examine blood samples from renal transplant patients and healthy blood donors for the presence and load of HHV-6 DNA and to determine the variants. Active HHV-6 infection was proved by RT-PCR, and active HCMV infection was diagnosed by pp65 antigenaemia test.</p> <p>Results</p> <p>HHV-6 viraemia was significantly more frequent in renal transplant patients compared to healthy blood donors (9/200 vs. 0/200; p = 0.004), while prevalence of HHV-6 latency was not significantly different (13/200 vs. 19/200; p > 0.05). Dominance of variant A was revealed in viraemias (8/9), and the frequency of HHV-6A was significantly higher in active infections compared with latency in renal transplant patients (8/9 vs. 2/13; p = 0.0015). Latency was established predominantly by HHV-6B both in renal transplant patients and in healthy blood donors (11/13 and 18/19). There was no statistical significant difference in occurrence of HCMV and HHV-6 viraemia in renal transplant patients (7/200 vs. 9/200). Statistical analysis did not reveal interaction between HHV-6 viraemia and clinical symptoms in our study.</p> <p>Conclusions</p> <p>Contrary to previous publications HHV-6A viraemia was found to be predominant in renal transplant patients. Frequency of variant A was significantly higher in cases of active infection then in latency.</p

    Reservoir stress path and induced seismic anisotropy: Results from linking coupled fluid-flow/geomechanical simulation with seismic modelling

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    We present a workflow linking coupled fluid-flow and geomechanical simulation with seismic modelling to predict seismic anisotropy induced by nonhydrostatic stress changes. We generate seismic models from coupled simulations to examine the relationship between reservoir geometry, stress path and seismic anisotropy. The results indicate that geometry influences the evolution of stress, which leads to stress-induced seismic anisotropy. Although stress anisotropy is high for the small reservoir, the effect of stress arching and the ability of the side-burden to support the excess load limit the overall change in effective stress and hence seismic anisotropy. For the extensive reservoir, stress anisotropy and induced seismic anisotropy are high. The extensive and elongate reservoirs experience significant compaction, where the inefficiency of the developed stress arching in the side-burden cannot support the excess load. The elongate reservoir displays significant stress asymmetry, with seismic anisotropy developing predominantly along the long-edge of the reservoir. We show that the link between stress path parameters and seismic anisotropy is complex, where the anisotropic symmetry is controlled not only by model geometry but also the nonlinear rock physics model used. Nevertheless, a workflow has been developed to model seismic anisotropy induced by non-hydrostatic stress changes, allowing field observations of anisotropy to be linked with geomechanical models

    Costs of insensitive acetylcholinesterase insecticide resistance for the malaria vector Anopheles gambiae homozygous for the G119S mutation

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    <p>Abstract</p> <p>Background</p> <p>The G119S mutation responsible for insensitive acetylcholinesterase resistance to organophosphate and carbamate insecticides has recently been reported from natural populations of <it>Anopheles gambiae </it>in West Africa. These reports suggest there are costs of resistance associated with this mutation for <it>An. gambiae</it>, especially for homozygous individuals, and these costs could be influential in determining the frequency of carbamate resistance in these populations.</p> <p>Methods</p> <p>Life-history traits of the AcerKis and Kisumu strains of <it>An. gambiae </it>were compared following the manipulation of larval food availability in three separate experiments conducted in an insecticide-free laboratory environment. These two strains share the same genetic background, but differ in being homozygous for the presence or absence of the G119S mutation at the <it>ace-1 </it>locus, respectively.</p> <p>Results</p> <p>Pupae of the resistant strain were significantly more likely to die during pupation than those of the susceptible strain. Ages at pupation were significantly earlier for the resistant strain and their dry starved weights were significantly lighter; this difference in weight remained when the two strains were matched for ages at pupation.</p> <p>Conclusions</p> <p>The main cost of resistance found for <it>An. gambiae </it>mosquitoes homozygous for the G119S mutation was that they were significantly more likely to die during pupation than their susceptible counterparts, and they did so across a range of larval food conditions. Comparing the frequency of G119S in fourth instar larvae and adults emerging from the same populations would provide a way to test whether this cost of resistance is being expressed in natural populations of <it>An. gambiae </it>and influencing the dynamics of this resistance mutation.</p

    Conceptual and Visual Features Contribute to Visual Memory for Natural Images

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    We examined the role of conceptual and visual similarity in a memory task for natural images. The important novelty of our approach was that visual similarity was determined using an algorithm [1] instead of being judged subjectively. This similarity index takes colours and spatial frequencies into account. For each target, four distractors were selected that were (1) conceptually and visually similar, (2) only conceptually similar, (3) only visually similar, or (4) neither conceptually nor visually similar to the target image. Participants viewed 219 images with the instruction to memorize them. Memory for a subset of these images was tested subsequently. In Experiment 1, participants performed a two-alternative forced choice recognition task and in Experiment 2, a yes/no-recognition task. In Experiment 3, testing occurred after a delay of one week. We analyzed the distribution of errors depending on distractor type. Performance was lowest when the distractor image was conceptually and visually similar to the target image, indicating that both factors matter in such a memory task. After delayed testing, these differences disappeared. Overall performance was high, indicating a large-capacity, detailed visual long-term memory

    Measurement of the cross-section of high transverse momentum vector bosons reconstructed as single jets and studies of jet substructure in pp collisions at √s = 7 TeV with the ATLAS detector

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    This paper presents a measurement of the cross-section for high transverse momentum W and Z bosons produced in pp collisions and decaying to all-hadronic final states. The data used in the analysis were recorded by the ATLAS detector at the CERN Large Hadron Collider at a centre-of-mass energy of √s = 7 TeV;{\rm Te}{\rm V}andcorrespondtoanintegratedluminosityof and correspond to an integrated luminosity of 4.6\;{\rm f}{{{\rm b}}^{-1}}.ThemeasurementisperformedbyreconstructingtheboostedWorZbosonsinsinglejets.ThereconstructedjetmassisusedtoidentifytheWandZbosons,andajetsubstructuremethodbasedonenergyclusterinformationinthejetcentreofmassframeisusedtosuppressthelargemultijetbackground.ThecrosssectionforeventswithahadronicallydecayingWorZboson,withtransversemomentum. The measurement is performed by reconstructing the boosted W or Z bosons in single jets. The reconstructed jet mass is used to identify the W and Z bosons, and a jet substructure method based on energy cluster information in the jet centre-of-mass frame is used to suppress the large multi-jet background. The cross-section for events with a hadronically decaying W or Z boson, with transverse momentum {{p}_{{\rm T}}}\gt 320\;{\rm Ge}{\rm V}andpseudorapidity and pseudorapidity |\eta |\lt 1.9,ismeasuredtobe, is measured to be {{\sigma }_{W+Z}}=8.5\pm 1.7$ pb and is compared to next-to-leading-order calculations. The selected events are further used to study jet grooming techniques

    Search for pair-produced long-lived neutral particles decaying to jets in the ATLAS hadronic calorimeter in ppcollisions at √s=8TeV

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    The ATLAS detector at the Large Hadron Collider at CERN is used to search for the decay of a scalar boson to a pair of long-lived particles, neutral under the Standard Model gauge group, in 20.3fb−1of data collected in proton–proton collisions at √s=8TeV. This search is sensitive to long-lived particles that decay to Standard Model particles producing jets at the outer edge of the ATLAS electromagnetic calorimeter or inside the hadronic calorimeter. No significant excess of events is observed. Limits are reported on the product of the scalar boson production cross section times branching ratio into long-lived neutral particles as a function of the proper lifetime of the particles. Limits are reported for boson masses from 100 GeVto 900 GeV, and a long-lived neutral particle mass from 10 GeVto 150 GeV
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