Transition from KPZ to Tilted Interface Critical Behavior in a Solvable Asymmetric Avalanche Model

We use a discrete-time formulation to study the asymmetric avalanche process [Phys. Rev. Lett. vol. 87, 084301 (2001)] on a finite ring and obtain an exact expression for the average avalanche size of particles as a function of toppling probabilities depending on parameters $\mu$ and $\alpha$. By mapping the model below and above the critical line onto driven interface problems, we show how different regimes of avalanches may lead to different types of critical interface behavior characterized by either annealed or quenched disorders and obtain exactly the related critical exponents which violate a well-known scaling relation when $\alpha \ne 2$.Comment: 10 page

Psychological distress and depression in urbanising elderly black persons

The findings of a comparative community survey of the socioeconomic, cultural and psychiatric state of elderly black persons in a newly settled township (Khayelitsha - 170 persons) and a long established one (Langa - 195 persons) revealed marked differences. Symptoms of psychological distress, depression and limitation of daily activities were generally more marked in the former and strikingly so among women: 66% had symptoms warranting further investigation and 44% would have been treated for a depressive disorder if seen by a psychiatrist. Extreme poverty existed in both townships but the Khayelitsha subjects were less well educated, their accommodation was poorer, and fewer had old-age pensions. Elderly black women in newly settled townships have therefore been identified as having high priority for psychiatric and social services

Exploiting single-cell expression to characterize co-expression replicability

BACKGROUND: Co-expression networks have been a useful tool for functional genomics, providing important clues about the cellular and biochemical mechanisms that are active in normal and disease processes. However, co-expression analysis is often treated as a black box with results being hard to trace to their basis in the data. Here, we use both published and novel single-cell RNA sequencing (RNA-seq) data to understand fundamental drivers of gene-gene connectivity and replicability in co-expression networks. RESULTS: We perform the first major analysis of single-cell co-expression, sampling from 31 individual studies. Using neighbor voting in cross-validation, we find that single-cell network connectivity is less likely to overlap with known functions than co-expression derived from bulk data, with functional variation within cell types strongly resembling that also occurring across cell types. To identify features and analysis practices that contribute to this connectivity, we perform our own single-cell RNA-seq experiment of 126 cortical interneurons in an experimental design targeted to co-expression. By assessing network replicability, semantic similarity and overall functional connectivity, we identify technical factors influencing co-expression and suggest how they can be controlled for. Many of the technical effects we identify are expression-level dependent, making expression level itself highly predictive of network topology. We show this occurs generally through re-analysis of the BrainSpan RNA-seq data. CONCLUSIONS: Technical properties of single-cell RNA-seq data create confounds in co-expression networks which can be identified and explicitly controlled for in any supervised analysis. This is useful both in improving co-expression performance and in characterizing single-cell data in generally applicable terms, permitting cross-laboratory comparison within a common framework

Rotation-induced 3D vorticity in 4He superfluid films adsorbed on a porous glass

Detailed study of torsional oscillator experiments under steady rotation up to 6.28 rad/sec is reported for a 4He superfluid monolayer film formed in 1 micrometer-pore diameter porous glass. We found a new dissipation peak with the height being in proportion to the rotation speed, which is located to the lower temperature than the vortex pair unbinding peak observed in the static state. We propose that 3D coreless vortices ("pore vortices") appear under rotation to explain this new peak. That is, the new peak originates from dissipation close to the pore vortex lines, where large superfluid velocity shifts the vortex pair unbinding dissipation to lower temperature. This explanation is confirmed by observation of nonlinear effects at high oscillation amplitudes.Comment: 4pages, 5figure

Transverse NMR relaxation as a probe of mesoscopic structure

Transverse NMR relaxation in a macroscopic sample is shown to be extremely sensitive to the structure of mesoscopic magnetic susceptibility variations. Such a sensitivity is proposed as a novel kind of contrast in the NMR measurements. For suspensions of arbitrary shaped paramagnetic objects, the transverse relaxation is found in the case of a small dephasing effect of an individual object. Strong relaxation rate dependence on the objects' shape agrees with experiments on whole blood. Demonstrated structure sensitivity is a generic effect that arises in NMR relaxation in porous media, biological systems, as well as in kinetics of diffusion limited reactions.Comment: 4 pages, 3 figure

Characterizing correlations of flow oscillations at bottlenecks

"Oscillations" occur in quite different kinds of many-particle-systems when two groups of particles with different directions of motion meet or intersect at a certain spot. We present a model of pedestrian motion that is able to reproduce oscillations with different characteristics. The Wald-Wolfowitz test and Gillis' correlated random walk are shown to hold observables that can be used to characterize different kinds of oscillations

L'acacia au Sénégal

Cette présentation propose une revue bibliographique de certains aspects de la nodulation des acacias, en particulier en ce qui concerne la diversité des rhizobiums qui leur sont associés, au regard de la taxonomie générale des rhizobiums, et développe plus en détails les derniers résultats obtenus au Sénégal dans ce domaine. (Résumé d'auteur

Woe from stones: commemoration, identity politics and Estonia's 'War of Monuments'

No abstract available

Ectodermal Wnt signaling, cell fate determination, and polarity of the skate gill arch skeleton

Funding Information: With thanks to Dr Kate Criswell and Dr Christine Hirschberger for advice, and to the University of Cambridge Wellcome PhD. Programme in Developmental Mechanisms. The authors were funded by a Wellcome PhD studentship (214953/Z/18/Z) to JMR, and by a Royal Society University Research Fellowship (UF130182 and URF\R\191007) and Royal Society Research Grant (RG140377) to JAG. For the purpose of Open Access, the authors have applied a CC BY public copyright license to any Author Accepted Manuscript version arising from this submission.Peer reviewedPublisher PD