3,848 research outputs found
Particle acceleration and radiation friction effects in the filamentation instability of pair plasmas
The evolution of the filamentation instability produced by two
counter-streaming pair plasmas is studied with particle-in-cell (PIC)
simulations in both one (1D) and two (2D) spatial dimensions. Radiation
friction effects on particles are taken into account. After an exponential
growth of both the magnetic field and the current density, a nonlinear
quasi-stationary phase sets up characterized by filaments of opposite currents.
During the nonlinear stage, a strong broadening of the particle energy spectrum
occurs accompanied by the formation of a peak at twice their initial energy. A
simple theory of the peak formation is presented. The presence of radiative
losses does not change the dynamics of the instability but affects the
structure of the particle spectra.Comment: 8 pages, 8 figures, submitted to MNRA
Follow-up after curative resection for gastric cancer. Is it time to tailor it?
There is still no consensus on the follow-up frequency and regimen after curative resection for gastric cancer. Moreover, controversy exists regarding the utility of follow-up in improving survival, and the recommendations of experts and societies vary considerably. The main reason to establish surveillance programs is to diagnose tumor recurrence or metachronous cancers early and to thereby provide prompt treatment and prolong survival. In the setting of gastric malignancies, other reasons have been put forth: (1) the detection of adverse effects of a previous surgery, such as malnutrition or digestive sequelae; (2) the collection of data; and (3) the identification of psychological and/or social problems and provision of appropriate support to the patients. No randomized controlled trials on the role of follow-up after curative resection of gastric carcinoma have been published. Herein, the primary retrospective series and systematic reviews on this subject are analyzed and discussed. Furthermore, the guidelines from international and national scientific societies are discussed. Follow-up is recommended by the majority of institutions; however, there is no real evidence that follow-up can improve long-term survival rates. Several studies have demonstrated that it is possible to stratify patients submitted to curative gastrectomy into different classes according to the risk of recurrence. Furthermore, promising studies have identified several molecular markers that are related to the risk of relapse and to prognosis. Based on these premises, a promising strategy will be to tailor follow-up in relation to the patient and tumor characteristics, molecular marker status, and individual risk of recurrence
Visualization in mixed-methods research on social networks
Introduction to edited special section of Sociological Research Onlin
Newly arrived migrant and refugee children in the British educational system
In 2009, Action for Social Integration was commissioned by London Councils to implement a four-year programme to improve the educational attainment for African and Caribbean children and young people in Barnet, Enfield and Haringey. Within this programme, the Social Policy Research Centre (SPRC) at Middlesex University has carried out a small-scale research project aimed at producing a guide for BME and migrant parents of children attending UK schools. The guide provides information to better understand the UK educational system, highlighting what may be different from those of other countries in the world and discussing issues such as language support and parents’ involvement. In order to identify the knowledge gaps and the main issues to include in the guide, the research team conducted a series of interviews, as well as an analysis and mapping of existing demographic data. The research findings presented in this report contribute to a better
understanding of the key challenges and opportunities facing BME parents and their children in London schools
Forgotten Irish
The research was commissioned by the Ireland Fund of Great Britain to inform its Forgotten Irish Campaign and decisions about where to deploy funds most effectively. It aimed to identify groups of Irish people who have experienced problems settling in Britain but who, for personal or economic reasons, are reluctant or unable to return to Ireland. They may be isolated and lack support in Britain, especially as they get older, but have little contact with family in Ireland. It is this group which has become the focus of the Forgotten Irish Campaign.
The research used a range of evidence – from national statistics, local research reports and key informant interviews – to identify particular groups who suffer disadvantage and specific issues which disproportionately affect the Irish population.
Some of these groups – such as single elderly men – are well known to organisations working with the Irish community. The research provides further evidence of the inter-related problems which they face. The research also uncovered evidence of other problems which particularly affect the Irish population in Britain and of groups within the Irish community who face specific difficulties but whose needs are not widely acknowledged either by mainstream service providers or by Irish services
EXONEST: The Bayesian Exoplanetary Explorer
The fields of astronomy and astrophysics are currently engaged in an
unprecedented era of discovery as recent missions have revealed thousands of
exoplanets orbiting other stars. While the Kepler Space Telescope mission has
enabled most of these exoplanets to be detected by identifying transiting
events, exoplanets often exhibit additional photometric effects that can be
used to improve the characterization of exoplanets. The EXONEST Exoplanetary
Explorer is a Bayesian exoplanet inference engine based on nested sampling and
originally designed to analyze archived Kepler Space Telescope and CoRoT
(Convection Rotation et Transits plan\'etaires) exoplanet mission data. We
discuss the EXONEST software package and describe how it accommodates
plug-and-play models of exoplanet-associated photometric effects for the
purpose of exoplanet detection, characterization and scientific hypothesis
testing. The current suite of models allows for both circular and eccentric
orbits in conjunction with photometric effects, such as the primary transit and
secondary eclipse, reflected light, thermal emissions, ellipsoidal variations,
Doppler beaming and superrotation. We discuss our new efforts to expand the
capabilities of the software to include more subtle photometric effects
involving reflected and refracted light. We discuss the EXONEST inference
engine design and introduce our plans to port the current MATLAB-based EXONEST
software package over to the next generation Exoplanetary Explorer, which will
be a Python-based open source project with the capability to employ third-party
plug-and-play models of exoplanet-related photometric effects.Comment: 30 pages, 8 figures, 5 tables. Presented at the 37th International
Workshop on Bayesian Inference and Maximum Entropy Methods in Science and
Engineering (MaxEnt 2017) in Jarinu/SP Brasi
The rna-binding ubiquitin ligase mex3a affects glioblastoma tumorigenesis by inducing ubiquitylation and degradation of rig-i
Glioblastoma multiforme (GB) is the most malignant primary brain tumor in humans, with an overall survival of approximatively 15 months. The molecular heterogeneity of GB, as well as its rapid progression, invasiveness and the occurrence of drug-resistant cancer stem cells, limits the efficacy of the current treatments. In order to develop an innovative therapeutic strategy, it is mandatory to identify and characterize new molecular players responsible for the GB malignant phenotype. In this study, the RNA-binding ubiquitin ligase MEX3A was selected from a gene expression analysis performed on publicly available datasets, to assess its biological and still-unknown activity in GB tumorigenesis. We find that MEX3A is strongly up-regulated in GB specimens, and this correlates with very low protein levels of RIG-I, a tumor suppressor involved in differentiation, apoptosis and innate immune response. We demonstrate that MEX3A binds RIG-I and induces its ubiquitylation and proteasome-dependent degradation. Further, the genetic depletion of MEX3A leads to an increase of RIG-I protein levels and results in the suppression of GB cell growth. Our findings unveil a novel molecular mechanism involved in GB tumorigenesis and suggest MEX3A and RIG-I as promising therapeutic targets in GB
The CLT Panels in Structural Restoration: Characteristics and Technical Regulations
Wood can represent a valid and important alternative to the most commonly
used structural materials for the restoration of masonry buildings, with a view to efficient, effective and "conscious" renovation. Today, the modern technologies allows to overcome the structural limits of solid wood due to its own anisotropy. The use of composite wood elements makes possible to obtain excellent mechanical performances that consent to evaluate aspects such as the use of low environmental impact retrofit strategies. The aim of this work is the analysis of mechanical parameters related to CLT (cross laminated timber) panels in order to determine their possible use in the structural restoration of masonry buildings. The CLT panels consist of solid wood planks superimposed so that each layer has the fibres rotated ninety degrees with respect to the adjacent layer. The layers (always in odd number and at least three) can be connected by discrete joints, pins and nails, or glued together. This onfiguration enables to product large structural elements with considerable thickness. Two different experimental test campaigns were carried out on samples of panels with three and five glued layers. The purpose of experimentation activities was to evaluate the bending deformation of the wooden elements and shear strength of the bonding sections. All the tests were processed according to the provisions contained in the UNI standards. The test results were then compared with different theoretical calculation models to determine the one that best represents the tested material. The tests outcomes have shown that some characteristics of the material, such as the remarkable ductility, open different scenarios of use for the CLT panels in the field of structural restoration of masonry buildings
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