976 research outputs found
Registering and uploading datasets in the generation CP central registry
Poster presented at Generation Challenge Programme 2009 Annual Research Meeting. Bamako (Mali), 20-23 Sep 200
Building networks to strengthen research data management advocacy and training
University College London (UCL) is a research-intensive university with 380
research departments, units, institutes and centres that are home to 12,000
research staff and research students. The university has been at the forefront
of delivering open access to research publications through Discovery, the
institutional publications repository. In August 2013 the Research Data
Executive Services Group published a Research Data Policy outlining the
responsibilities of research staff and students and describing the variety of
institutional services that are available to support Research Data Management
(RDM). UCL’s Research Data Policy is supported by two Research Data Support
Offi cers (RDSOs) who work as part of the Liaison and Support Services within
UCL Library Services and work on a regular basis with the Research Data
Service based in Research IT Services and a number of other central services.
This article will briefl y describe how the RDSOs have developed links with other
services in order to improve awareness of RDM services
Robustness of ergodic properties of non-autonomous piecewise expanding maps
Recently, there has been an increasing interest in non-autonomous composition of perturbed hyperbolic systems: composing perturbations of a given hyperbolic map results in statistical behaviour close to that of . We show this fact in the case of piecewise regular expanding maps. In particular, we impose conditions on perturbations of this class of maps that include situations slightly more general than what has been considered so far, and prove that these are stochastically stable in the usual sense. We then prove that the evolution of a given distribution of mass under composition of time-dependent perturbations (arbitrarily—rather than randomly—chosen at each step) close to a given map remains close to the invariant mass distribution of . Moreover, for almost every point, Birkhoff averages along trajectories do not fluctuate wildly. This result complements recent results on memory loss for non-autonomous dynamical systems
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Restraint, disinhibition and food-related processing bias
This study examined associations between restraint, disinhibition and food-related processing bias (FPB, assessed by the emotional Stroop task) in males and females in the UK, Greece and Iran. Results showed high restraint was associated with higher FPB. However, high restrained current dieters showed lower FPB that high restrained non-dieters. There was no significant difference in FPB for those showing high versus low disinhibition. Results are discussed in relation to theories of incentive salience and current concerns
Revealing dynamics, communities and criticality from data
Complex systems such as ecological communities and neuron networks are essential parts of our everyday lives. These systems are composed of units which interact through intricate networks. The ability to predict sudden changes in the dynamics of these networks, known as critical transitions, from data is important to avert disastrous consequences of major disruptions. Predicting such changes is a major challenge as it requires forecasting the behaviour for parameter ranges for which no data on the system is available. We address this issue for networks with weak individual interactions and chaotic local dynamics. We do this by building a model network, termed an {}, consisting of the underlying local dynamics and a statistical description of their interactions. We show that behaviour of such networks can be decomposed in terms of an emergent deterministic component and a {} term. Traditionally, such fluctuations are filtered out. However, as we show, they are key to accessing the interaction structure. { We illustrate this approach on synthetic time-series of realistic neuronal interaction networks of the cat cerebral cortex and on experimental multivariate data of optoelectronic oscillators. } We reconstruct the community structure by analysing the stochastic fluctuations generated by the network and predict critical transitions for coupling parameters outside the observed range
Changes in the electroencephalographic spectrum in response to smoking cues in smokers and ex-smokers
Aims: To investigate the changes in the electroencephalographic (EEG) spectrum in smokers during exposure to a neutral and a smoking-related cue to determine whether these EEG changes are still present in ex-smokers after prolonged abstinence and to examine the relationship between the power in each spectral bandwidth and subjective craving. Methods: EEG frequencies in response to a smoking-related and a neutral cue were examined in 23 smokers and 21 ex-smokers, who quit smoking for 1.4 years on average. Additionally, self-report measures of cigarette craving and nicotine dependence were obtained. The spectral power of each bandwidth was computed, log-transformed, and analyzed using a within-subject design. Differences between EEG activity under neutral and smoking conditions were correlated with differences between pre- and postexperimental subjective craving. Results: Increases in reward craving (desire and intention to smoke) were associated with reduced theta activity, whereas increases in withdrawal craving (reduction of negative affect and withdrawal symptoms) were correlated with increases in both delta and higher alpha power. Furthermore, in smokers, but not in ex-smokers, a significant beta power increase was observed between the neutral condition and the smoking condition. Conclusion: Since the beta band is associated with arousal, attention, and alertness, it is suggested that the beta increase in response to the smoking cue might reflect an enhanced allocation of resources to smoking-related stimuli, i.e. a processing bias, which is an important feature of substance abuse. Since ex-smokers do not respond to the smoking cue with beta activity enhancement, we preliminarily conclude that smoking cues do not arouse ex-smokers or capture their attention as much as they do in smokers
Computer Vision for the Humanities: An Introduction to Deep Learning for Image Classification (Part 1)
This is the first of a two-part lesson introducing deep learning based computer vision methods for humanities research. Using a dataset of historical newspaper advertisements and the fastai Python library, the lesson walks through the pipeline of training a computer vision model to perform image classification
The Retrosplenial Cortex: Intrinsic Connectivity and Connections with the (Para)Hippocampal Region in the Rat. An Interactive Connectome
A connectome is an indispensable tool for brain researchers, since it quickly provides comprehensive knowledge of the brain's anatomical connections. Such knowledge lies at the basis of understanding network functions. Our first comprehensive and interactive account of brain connections comprised the rat hippocampal–parahippocampal network. We have now added all anatomical connections with the retrosplenial cortex (RSC) as well as the intrinsic connections of this region, because of the interesting functional overlap between these brain regions. The RSC is involved in a variety of cognitive tasks including memory, navigation, and prospective thinking, yet the exact role of the RSC and the functional differences between its subdivisions remain elusive. The connectome presented here may help to define this role by providing an unprecedented interactive and searchable overview of all connections within and between the rat RSC, parahippocampal region and hippocampal formation
Device operation of conjugated polymer/zinc oxide bulk heterojunction solar cells
Solar cells based on a poly (p-phenylene vinylene) (PPV) derivative and zinc oxide nanoparticles can reach a power conversion efficiency of 1.6%. The transport of electrons and holes in these promising devices is characterized and it is found that the electron mobility is equal to 2.8 x 10(-9) m(2) V-1 s(-1), whereas the hole mobility amounts to 5.5 x 10(-10) m(2) V-1 s(-1). By modeling the current-voltage characteristics under illumination it is found that the performance of PPV/zinc oxide solar cells is limited by the charge-carrier mobilities. Subsequently, how to further improve the efficiency is discussed
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