1,347 research outputs found

    A configural dominant account of contextual cueing : configural cues are stronger than colour cues

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    Previous work has shown that reaction times to find a target in displays that have been repeated are faster than those for displays that have never been seen before. This learning effect, termed “contextual cueing” (CC), has been shown using contexts such as the configuration of the distractors in the display and the background colour. However, it is not clear how these two contexts interact to facilitate search. We investigated this here by comparing the strengths of these two cues when they appeared together. In Experiment 1, participants searched for a target that was cued by both colour and distractor configural cues, compared with when the target was only predicted by configural information. The results showed that the addition of a colour cue did not increase contextual cueing. In Experiment 2, participants searched for a target that was cued by both colour and distractor configuration compared with when the target was only cued by colour. The results showed that adding a predictive configural cue led to a stronger CC benefit. Experiments 3 and 4 tested the disruptive effects of removing either a learned colour cue or a learned configural cue and whether there was cue competition when colour and configural cues were presented together. Removing the configural cue was more disruptive to CC than removing colour, and configural learning was shown to overshadow the learning of colour cues. The data support a configural dominant account of CC, where configural cues act as the stronger cue in comparison to colour when they are presented together

    Mechano-chemical manipulation of Sn chains on Si(1 0 0) by NC-AFM

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    We investigate the atomic structure of Sn dimer chains grown on the Si(1 0 0) surface using non-contact atomic force microscopy (NC-AFM) at cryogenic temperatures. We find that similar to the native Si(1 0 0) dimer structure, the ground state of the Sn dimer structure is buckled at low temperature. At 5 K we show that the buckling state of the Sn dimers may be controllably, and reversibly, manipulated with atomic precision by close approach of the tip, without modification of the underlying substrate buckling structure. At intermediate cryogenic temperatures we observe changes in the configuration of the dimer chains in the region where the tip-sample interaction is very weak, suggesting that the energy barrier to transit between configurations is sufficiently small to be surmounted at 78 K

    Biologie de reproduction chez Thaumatococcus Daniellii (benn.) Benth. et hook. (marantaceae) en Cîte D’ivoire

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    Le processus de reproduction de Thaumatococcus daniellii a été étudié en vue d'une domestication à but économique. Ainsi, l'identification des animaux contribuant à la pollinisation a été réalisée à partir d'observations effectuées dans un dispositif expérimental réglementant l'accÚs différentiel des animaux aux parcelles. Une pollinisation manuelle suivie de l'analyse des fruits, par rapport à la teneur engraines, ont été effectuées. Les résultats ont révélé l'intervention d'agents extérieurs dans le processus de pollinisation, impliquant un phénomÚne d'allogamie chez cette plante. Ces agents extérieurs qui agissent en synergie sont Nectarinia olivacea (oiseau) et Aphis sp. (puceron). La prépondérance des fruits contenant une graine,l'échec élevé de l'autopollinisation et la prédominance d'une l'allopollinisation traduisent une incompatibilité génétique dans la régulation de la pollinisation des fleurs chez cette plante

    Failure to report protocol violations in clinical trials: a threat to internal validity?

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    <p>Abstract</p> <p>Background</p> <p>Excessive protocol violations (PV), which can be defined as preventable mistakes in study conduct, may result in patient harm and introduce errors into a clinical trial's results leading to flawed trial conclusions.</p> <p>The purpose of this project was to gain a better understanding of reported PVs, to describe current practice with regards to the use of methods for the reduction of PVs and to investigate relationships between clinical trial characteristics and PVs.</p> <p>Methods</p> <p>We reviewed 80 clinical trials conducted across a broad range of medical specialties published in four major general medical journals (The Lancet, NEJM, JAMA, BMJ). Eligible papers were identified using a PubMed search. For each included trial, two authors independently abstracted information on trial characteristics, PV reporting and PV rates and interventions used to reduce PVs. PVs were categorised into one of five distinct types: enrolment, randomisation, study intervention, patient compliance and data collection errors. Associations between PVs and study characteristics were investigated using logistic regression.</p> <p>Results</p> <p>Eighty clinical trials (20 from each journal) were identified from 101 consecutive PubMed abstracts. The median number of participants was 701 (range: 20 to 162, 367) and the median number of participating sites was 15 (range: 1 to 701). Nineteen percent (15/80) of included trials were single centre trials. The median study duration was 24 months (range: 5.81 - 127 months) and 74% (59/80) of included trials were primarily academic funded.</p> <p>Thirty two percent (26/80) of included trials failed to provide explicit reporting of any type of PV and none (0/80) of the trials provided explicit reporting of all five types of PVs. Larger clinical trials (more patients, more sites, longer duration, more complex management structure) were more likely to have more complete reporting of PV's.</p> <p>Only 9% (7/80) of trials reported the use of a specific study method to prevent PVs. Use of a run-in phase was the only method reported.</p> <p>Conclusions</p> <p>PVs are under-reported. Although the CONSORT statement provides guidance on the reporting of PVs, reporting requirements are not explicit for all types of PVs. As a first step towards improved reporting by authors, we recommend the CONSORT statement highlight the importance of PVs by making reporting requirements more explicit.</p

    Attitude toward protest uniquely predicts (normative and nonnormative) political action by (advantaged and disadvantaged) group members

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    This is the author accepted manuscript. The final version is available on open access via the DOI in this recordOpen Practices: All data and materials for Studies 1-5 have been made publicly available via Open Science Framework and can be accessed at https://osf.io/emk5j. The plan for Study 4 was preregistered at Open Science Framework (https://osf.io/emk5j). This article has received badges for Open Data, Open Materials, and Preregistration. More information about the Open Practices badges can be found at https://osf.io/tvyxz/wiki/home/.We find evidence that explicit (but not implicit) measures of general attitude towards protest uniquely predict normative and nonnormative political action tendencies, and behavior, over and above extant models of political action. Protest attitude uniquely predicts both the political action tendencies of members of disadvantaged groups and willingness to engage in solidarity-based action on behalf of such groups. Furthermore, we find some evidence that protest attitude is able to account for the effects of mobilization messages over a political issue; these messages increase political action tendencies by making attitude towards protest more positive. The results indicate that overall attitude toward protest reflects a wide array of affective, cognitive, and behavioral factors associated with protest that more specific, established predictors of collective political action do not tap. As such, general protest attitude offers an important addition to extant models of collective political action and efforts to examine the psychological processes underpinning political cognition and action.Economic and Social Research Council (ESRC

    Simulated structure and imaging of NTCDI on Si(1 1 1)-7 × 7 : a combined STM, NC-AFM and DFT study

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    The adsorption of naphthalene tetracarboxylic diimide (NTCDI) on Si(1 1 1)-7 × 7 is investigated through a combination of scanning tunnelling microscopy (STM), noncontact atomic force microscopy (NC-AFM) and density functional theory (DFT) calculations. We show that NTCDI adopts multiple planar adsorption geometries on the Si(1 1 1)-7 × 7 surface which can be imaged with intramolecular bond resolution using NC-AFM. DFT calculations reveal adsorption is dominated by covalent bond formation between the molecular oxygen atoms and the surface silicon adatoms. The chemisorption of the molecule is found to induce subtle distortions to the molecular structure, which are observed in NC-AFM images

    Pairs of Fish Resolve Conflicts over Coordinated Movement by Taking Turns

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    SummaryWhen individuals stand to gain by interacting with one another, but disagree over their preferred course of collective action, coordination can be hard to achieve [1–4]. In previous work, we found that pairs of stickleback fish prefer to synchronize their trips out of cover to look for food [5], possibly because this reduces perceived predation risk [6]. To create a degree of conflict over group coordination, we trained individual fish to expect food at one of two alternative, exposed locations and paired individuals with different expectations. Compared with isolated individuals, members of a pair showed a significantly increased tendency to alternate between foraging sites, together taking turns to visit first one individual's favored site and then the other individual's. Using a Markov-chain model to infer the individual rules underlying their joint behavior, we found that fish respond to a partner that breaks the pattern of alternation by themselves reverting to less regular behavior. Our results confirm theoretical predictions that conflict over group coordination can be resolved by taking turns [7–10] and show that, in this system, the pattern of alternation is actively monitored and maintained

    MicroRNA regulation of the paired-box transcription factor Pax3 confers robustness to developmental timing of myogenesis

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    Commitment of progenitors in the dermomyotome to myoblast fate is the first step in establishing the body musculature. Pax3 is a crucial transcription factor, important for skeletal muscle development and expressed in myogenic progenitors in the dermomyotome of developing somites and in migratory muscle progenitors that populate the limb buds. Down-regulation of Pax3 is essential to ignite the myogenic program, including up-regulation of myogenic regulators, Myf-5 and MyoD. MicroRNAs (miRNAs) confer robustness to developmental timing by posttranscriptional repression of genetic programs that are related to previous developmental stages or to alternative cell fates. Here we demonstrate that the muscle-specific miRNAs miR-1 and miR-206 directly target Pax3. Antagomir-mediated inhibition of miR-1/miR-206 led to delayed myogenic differentiation in developing somites, as shown by transient loss of myogenin expression. This correlated with increased Pax3 and was phenocopied using Pax3-specific target protectors. Loss of myogenin after antagomir injection was rescued by Pax3 knockdown using a splice morpholino, suggesting that miR-1/miR-206 control somite myogenesis primarily through interactions with Pax3. Our studies reveal an important role for miR-1/miR-206 in providing precision to the timing of somite myogenesis. We propose that posttranscriptional control of Pax3 downstream of miR-1/miR-206 is required to stabilize myoblast commitment and subsequent differentiation. Given that mutually exclusive expression of miRNAs and their targets is a prevailing theme in development, our findings suggest that miRNA may provide a general mechanism for the unequivocal commitment underlying stem cell differentiation

    Has phytodetritus processing by an abyssal soft-sediment community recovered 26 years after an experimental disturbance?

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    The potential harvest of polymetallic nodules will heavily impact the abyssal, soft sediment ecosystem by removing sediment, hard substrate, and associated fauna inside mined areas. It is therefore important to know whether the ecosystem can recover from this disturbance and if so at which rate. The first objective of this study was to measure recovery of phytodetritus processing by the benthic food web from a sediment disturbance experiment in 1989. The second objective was to determine the role of holothurians in the uptake of fresh phytodetritus by the benthic food web. To meet both objectives, large benthic incubation chambers (CUBEs; 50 × 50 × 50 cm) were deployed inside plow tracks (with and without holothurian presence) and at a reference site (holothurian presence, only) at 4100 m water depth. Shortly after deployment, 13C- and 15N-labeled phytodetritus was injected in the incubation chambers and during the subsequent 3-day incubation period, water samples were taken five times to measure the production of 13C-dissolved inorganic carbon over time. At the end of the incubation, holothurians and sediment samples were taken to determine biomass, densities and incorporation of 13C and 15N into bacteria, nematodes, macrofauna, and holothurians. For the first objective, the results showed that biomass of bacteria, nematodes and macrofauna did not differ between reference sites and plow track sites when holothurians were present. Additionally, meiofauna and macrofauna taxonomic composition was not significantly different between the sites. In contrast, total 13C uptake by bacteria, nematodes and holothurians was significantly lower at plow track sites compared to reference sites, though the number of replicates was low. This result suggests that important ecosystem functions such as organic matter processing have not fully recovered from the disturbance that occurred 26 years prior to our study. For the second objective, the analysis indicated that holothurians incorporated 2.16 × 10−3 mmol labile phytodetritus C m−2 d−1 into their biomass, which is one order of magnitude less as compared to bacteria, but 1.3 times higher than macrofauna and one order of magnitude higher than nematodes. Additionally, holothurians incorporated more phytodetritus carbon per unit biomass than macrofauna and meiofauna, suggesting a size-dependence in phytodetritus carbon uptake
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