Shot noise in resonant tunneling through a zero-dimensional state with a complex energy spectrum

We investigate the noise properties of a GaAs/AlGaAs resonant tunneling structure at bias voltages where the current characteristic is determined by single electron tunneling. We discuss the suppression of the shot noise in the framework of a coupled two-state system. For large bias voltages we observed super-Poissonian shot noise up to values of the Fano factor $\alpha \approx 10$.Comment: 4 pages, 4 figures, accepted for Phys. Rev.

Enhanced fluctuations of the tunneling density of states near bottoms of Landau bands measured by a local spectrometer

We have found that the local density of states fluctuations (LDOSF) in a disordered metal, detected using an impurity in the barrier as a spectrometer, undergo enhanced (with respect to SdH and dHvA effects) oscillations in strong magnetic fields, omega _c\tau > 1. We attribute this to the dominant role of the states near bottoms of Landau bands which give the major contribution to the LDOSF and are most strongly affected by disorder. We also demonstrate that in intermediate fields the LDOSF increase with B in accordance with the results obtained in the diffusion approximation.Comment: 4 pages, 4 figure

RadioActive101 Practices

The RadioActive101 Practices publication is now complete (in both PDF and EPUB versions) following consultation with all our partners. The report contains many of the common practices developed and refined by participants and RadioActive researchers across this European partnership over the last two years. And there are several examples of the significant impact felt by some of the individuals who became ‘radio-activists’ along the way

RadioActive Europe: promoting engagement, informal learning and employability of at risk and excluded people across Europe through internet radio and social media (RadioActive101)

RadioActive is an innovative education project that has developed and implemented a radical technology-enabled pedagogy to promote the inclusion, engagement and informal learning of excluded people, or those at-risk of exclusion, across Europe. It does this through harnessing primarily internet radio and also social media, or, as our motto states: "RadioActive101: Learning through radio, learning for life!" The project developed, implemented and is sustaining a pan-European Internet Radio platform, incorporating Web 2.0 ideas and features. This is linked to innovative community based pedagogies to address inclusion, employability and active citizenship in an original and exciting way, whilst recognising informal learning through electronic Open badges. The consortium was led by the University of East London (UK), with other partners from Portugal (CIMJ), Germany (UKL), the UK (Pontydysgu), Romania (ODIP) and Malta (KIC). These partners have direct links and ongoing collaborations with 13 primary Associate Partner organisations and a network of 39 mostly grass-roots organisations that facilitate access to the RadioActive101 participants, or 'radio-activists' as we define them. So the Associate Partners perform and deliver RadioActive 'on the ground' and are the vehicle for the learning experiences required for their production. These represent a particularly diverse range of groups and this was deliberate to allow us to test and refine our model, and show that it potentially works with virtually all excluded groups, and across Europe. We actively developed, implemented and ran five national RadioActive 'stations' (or hubs) that are accessible via the European Support Hub (ESH). Through making the radio shows the target groups (schools, vocational education, Higher Education, informal and adult education) are developing digital competencies and employability skills 'in vivo' that are transferable to the 21st Century workplace. These competencies and skills align with six of the EU Key Competencies for Lifelong Learning and we have developed a progression and accreditation model linking the key competencies to RadioActive activities and performances that are recognised through Open electronic 'badges'. These badges provide concrete recognition measures and represent proficiencies that are relevant to further education or employment in particular related to the knowledge and creative and digital industries. Evaluation findings were obtained through conducting a phased evaluation incorporating a full in depth ‘prototype’ evaluation in the UK during year one, a similar evaluation in Portugal and a smaller one in Germany in year two, that were followed by a broader and larger international survey of radio-activists (subjects) towards the end of the project. All these showed particularly positive and interesting results, such as the delivery of additional impact and value beyond the informal learning of technical and employability skills. Additionally, we found improvements in confidence, self-esteem and general self-efficacy of individuals, plus additional improvements in groups and organisations. It appears that once our excluded groups developed the confidence and competence to perform activities they often thought were beyond them, they seem then empowered, to learn many other things and to develop a number of key competencies. At the European and national levels we have produced an extensive amount of dissemination activities to make the RadioActive Europe project public and well known, and also won two additional funding awards towards the end of the project.Other exploitation activities include embedding locally and internationally, with the latter being realised through the establishment of an international Foundation that will also support and advise about funding models to support further expansion at the European level

Identification of gene co-regulatory modules and associated cis-elements involved in degenerative heart disease

<p>Abstract</p> <p>Background</p> <p>Cardiomyopathies, degenerative diseases of cardiac muscle, are among the leading causes of death in the developed world. Microarray studies of cardiomyopathies have identified up to several hundred genes that significantly alter their expression patterns as the disease progresses. However, the regulatory mechanisms driving these changes, in particular the networks of transcription factors involved, remain poorly understood. Our goals are (A) to identify modules of co-regulated genes that undergo similar changes in expression in various types of cardiomyopathies, and (B) to reveal the specific pattern of transcription factor binding sites, <it>cis</it>-elements, in the proximal promoter region of genes comprising such modules.</p> <p>Methods</p> <p>We analyzed 149 microarray samples from human hypertrophic and dilated cardiomyopathies of various etiologies. Hierarchical clustering and Gene Ontology annotations were applied to identify modules enriched in genes with highly correlated expression and a similar physiological function. To discover motifs that may underly changes in expression, we used the promoter regions for genes in three of the most interesting modules as input to motif discovery algorithms. The resulting motifs were used to construct a probabilistic model predictive of changes in expression across different cardiomyopathies.</p> <p>Results</p> <p>We found that three modules with the highest degree of functional enrichment contain genes involved in myocardial contraction (n = 9), energy generation (n = 20), or protein translation (n = 20). Using motif discovery tools revealed that genes in the contractile module were found to contain a TATA-box followed by a CACC-box, and are depleted in other GC-rich motifs; whereas genes in the translation module contain a pyrimidine-rich initiator, Elk-1, SP-1, and a novel motif with a GCGC core. Using a naïve Bayes classifier revealed that patterns of motifs are statistically predictive of expression patterns, with odds ratios of 2.7 (contractile), 1.9 (energy generation), and 5.5 (protein translation).</p> <p>Conclusion</p> <p>We identified patterns comprised of putative <it>cis</it>-regulatory motifs enriched in the upstream promoter sequence of genes that undergo similar changes in expression secondary to cardiomyopathies of various etiologies. Our analysis is a first step towards understanding transcription factor networks that are active in regulating gene expression during degenerative heart disease.</p

An astrocyte-dependent mechanism for neuronal rhythmogenesis

Communication between neurons rests on their capacity to change their firing pattern to encode different messages. For several vital functions, such as respiration and mastication, neurons need to generate a rhythmic firing pattern. Here we show in the rat trigeminal sensori-motor circuit for mastication that this ability depends on regulation of the extracellular Ca2+ concentration ([Ca2+]e) by astrocytes. In this circuit, astrocytes respond to sensory stimuli that induce neuronal rhythmic activity, and their blockade with a Ca2+ chelator prevents neurons from generating a rhythmic bursting pattern. This ability is restored by adding S100b, an astrocytic Ca2+-binding protein, to the extracellular space, while application of an anti-S100b antibody prevents generation of rhythmic activity. These results indicate that astrocytes regulate a fundamental neuronal property: the capacity to change firing pattern. These findings may have broad implications for many other neural networks whose functions depend on the generation of rhythmic activity

Landslides Triggered by the MW 7.8 14 November 2016 Kaikoura Earthquake, New Zealand

The MW 7.8 14 November 2016 Kaikoura earthquake generated more than 10000 landslides over a total area of about 10000 km2, with the majority concentrated in a smaller area of about 3600 km2. The largest landslide triggered by the earthquake had an approximate volume of 20 (±2) M m3, with a runout distance of about 2.7 km, forming a dam on the Hapuku River. In this paper, we present version 1.0 of the landslide inventory we have created for this event. We use the inventory presented in this paper to identify and discuss some of the controls on the spatial distribution of landslides triggered by the Kaikoura earthquake. Our main findings are (1) the number of medium to large landslides (source area ≥10000 m2) triggered by the Kaikoura earthquake is smaller than for similar sized landslides triggered by similar magnitude earthquakes in New Zealand; (2) seven of the largest eight landslides (from 5 to 20 x 106 m3) occurred on faults that ruptured to the surface during the earthquake; (3) the average landslide density within 200 m of a mapped surface fault rupture is three times that at a distance of 2500 m or more from a mapped surface fault rupture ; (4) the “distance to fault” predictor variable, when used as a proxy for ground-motion intensity, and when combined with slope angle, geology and elevation variables, has more power in predicting landslide probability than the modelled peak ground acceleration or peak ground velocity; and (5) for the same slope angles, the coastal slopes have landslide point densities that are an order of magnitude greater than those in similar materials on the inland slopes, but their source areas are significantly smaller