108 research outputs found

    Focused-attention meditation increases cognitive control during motor sequence performance: Evidence from the N2 cortical evoked potential

    Get PDF
    Previous work found that single-session focused attention meditation (FAM) enhanced motor sequence learning through increased cognitive control as a mechanistic action, although electrophysiological correlates of sequence learning performance following FAM were not investigated. We measured the persistent frontal N2 event-related potential (ERP) that is closely related to cognitive control processes and its ability to predict behavioural measures. Twenty-nine participants were randomised to one of three conditions reflecting the level of FAM experienced prior to a serial reaction time task (SRTT): 21 sessions of FAM (FAM21, N = 12), a single FAM session (FAM1, N = 9) or no preceding FAM control (Control, N = 8). Continuous 64-channel EEG were recorded during SRTT and N2 amplitudes for correct trials were extracted. Component amplitude, regions of interests, and behavioural outcomes were compared using mixed effects regression models between groups. FAM21 exhibited faster reaction time performances in majority of the learning blocks compared to FAM1 and Control. FAM21 also demonstrated a significantly more pronounced N2 over majority of anterior and central regions of interests during SRTT compared to the other groups. When N2 amplitudes were modelled against general learning performance, FAM21 showed the greatest rate of amplitude decline over anterior and central regions. The combined results suggest that FAM training provided greater cognitive control enhancement for improved general performance, and less pronounced effects for sequence-specific learning performance compared to the other groups. Importantly, FAM training facilitates dynamic modulation of cognitive control: lower levels of general learning performance was supported by greater levels of activation, whilst higher levels of general learning exhibited less activation

    The Neural Basis of Cognitive Efficiency in Motor Skill Performance from Early Learning to Automatic Stages

    Get PDF

    Recurrent governance challenges in the implementation and alignment of flood risk management strategies: a review

    Get PDF
    In Europe increasing flood risks challenge societies to diversify their Flood Risk Management Strategies (FRMSs). Such a diversification implies that actors not only focus on flood defence, but also and simultaneously on flood risk prevention, mitigation, preparation and recovery. There is much literature on the implementation of specific strategies and measures as well as on flood risk governance more generally. What is lacking, though, is a clear overview of the complex set of governance challenges which may result from a diversification and alignment of FRM strategies. This paper aims to address this knowledge gap. It elaborates on potential processes and mechanisms for coordinating the activities and capacities of actors that are involved on different levels and in different sectors of flood risk governance, both concerning the implementation of individual strategies and the coordination of the overall set of strategies. It identifies eight overall coordination mechanisms that have proven to be useful in this respect

    Conserved and variable correlated mutations in the plant MADS protein network

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Plant MADS domain proteins are involved in a variety of developmental processes for which their ability to form various interactions is a key requisite. However, not much is known about the structure of these proteins or their complexes, whereas such knowledge would be valuable for a better understanding of their function. Here, we analyze those proteins and the complexes they form using a correlated mutation approach in combination with available structural, bioinformatics and experimental data.</p> <p>Results</p> <p>Correlated mutations are affected by several types of noise, which is difficult to disentangle from the real signal. In our analysis of the MADS domain proteins, we apply for the first time a correlated mutation analysis to a family of interacting proteins. This provides a unique way to investigate the amount of signal that is present in correlated mutations because it allows direct comparison of mutations in various family members and assessing their conservation. We show that correlated mutations in general are conserved within the various family members, and if not, the variability at the respective positions is less in the proteins in which the correlated mutation does not occur. Also, intermolecular correlated mutation signals for interacting pairs of proteins display clear overlap with other bioinformatics data, which is not the case for non-interacting protein pairs, an observation which validates the intermolecular correlated mutations. Having validated the correlated mutation results, we apply them to infer the structural organization of the MADS domain proteins.</p> <p>Conclusion</p> <p>Our analysis enables understanding of the structural organization of the MADS domain proteins, including support for predicted helices based on correlated mutation patterns, and evidence for a specific interaction site in those proteins.</p

    Blood Pressure During Endovascular Treatment Under Conscious Sedation or Local Anesthesia

    Get PDF
    OBJECTIVE: To evaluate the role of blood pressure (BP) as mediator of the effect of conscious sedation (CS) compared to local anesthesia (LA) on functional outcome after endovascular treatment (EVT). METHODS: Patients treated in the Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands (MR CLEAN) Registry centers with CS or LA as preferred anesthetic approach during EVT for ischemic stroke were analyzed. First, we evaluated the effect of CS on area under the threshold (AUT), relative difference between baseline and lowest procedural mean arterial pressure (∆LMAP), and procedural BP trend, compared to LA. Second, we assessed the association between BP and functional outcome (modified Rankin Scale [mRS]) with multivariable regression. Lastly, we evaluated whether BP explained the effect of CS on mRS. RESULTS: In 440 patients with available BP data, patients treated under CS (n = 262) had larger AUTs (median 228 vs 23 mm Hg*min), larger ∆LMAP (median 16% vs 6%), and a more negative BP trend (-0.22 vs -0.08 mm Hg/min) compared to LA (n = 178). Larger ∆LMAP and AUTs were associated with worse mRS (adjusted common odds ratio [acOR] per 10% drop 0.87, 95% confidence interval [CI] 0.78-0.97, and acOR per 300 mm Hg*min 0.89, 95% CI 0.82-0.97). Patients treated under CS had worse mRS compared to LA (acOR 0.59, 95% CI 0.40-0.87) and this association remained when adjusting for ∆LMAP and AUT (acOR 0.62, 95% CI 0.42-0.92). CONCLUSIONS: Large BP drops are associated with worse functional outcome. However, BP drops do not explain the worse outcomes in the CS group

    From InSb Nanowires to Nanocubes: Looking for the Sweet Spot

    Get PDF
    High aspect ratios are highly desired to fully exploit the one-dimensional properties of indium antimonide nanowires. Here we systematically investigate the growth mechanisms and find parameters leading to long and thin nanowires. Variation of the V/III ratio and the nanowire density are found to have the same influence on the “local” growth conditions and can control the InSb shape from thin nanowires to nanocubes. We propose that the V/III ratio controls the droplet composition and the radial growth rate and these parameters determine the nanowire shape. A sweet spot is found for nanowire interdistances around 500 nm leading to aspect ratios up to 35. High electron mobilities up to 3.5 × 10^4 cm^2 V^(–1) s^(–1) enable the realization of complex spintronic and topological devices

    Population and Environmental Correlates of Maize Yields in Mesoamerica: a Test of Boserup’s Hypothesis in the Milpa

    Full text link
    Using a sample of 40 sources reporting milpa and mucuna-intercropped maize yields in Mesoamerica, we test Boserup’s (1965) prediction that fallow is reduced as a result of growing population density. We further examine direct and indirect effects of population density on yield. We find only mixed support for Boserupian intensification. Fallow periods decrease slightly with increasing population density in this sample, but the relationship is weak. Controlling for other covariates, fallow-unadjusted maize yields first rise then fall with population density. Fallow-adjusted maize yields peak at 390 kg/ha/yr for low population densities (8 persons / km2) and decline to around 280 kg/ha/yr for the highest population densities observed in our dataset. Fallow practices do not appear to mediate the relationship between population density and yield. The multi-level modeling methods we adopt allow for data clustering, accurate estimates of group-level variation, and they generate conditional predictions, all features essential to the comparative study of prehistoric and contemporary agricultural yields
    corecore