Charge and matter distributions and form factors of light, medium and heavy neutron-rich nuclei

Results of charge form factors calculations for several unstable neutron-rich isotopes of light, medium and heavy nuclei (He, Li, Ni, Kr, Sn) are presented and compared to those of stable isotopes in the same isotopic chain. For the lighter isotopes (He and Li) the proton and neutron densities are obtained within a microscopic large-scale shell-model, while for heavier ones Ni, Kr and Sn the densities are calculated in deformed self-consistent mean-field Skyrme HF+BCS method. We also compare proton densities to matter densities together with their rms radii and diffuseness parameter values. Whenever possible comparison of form factors, densities and rms radii with available experimental data is also performed. Calculations of form factors are carried out both in plane wave Born approximation (PWBA) and in distorted wave Born approximation (DWBA). These form factors are suggested as predictions for the future experiments on the electron-radioactive beam colliders where the effect of the neutron halo or skin on the proton distributions in exotic nuclei is planned to be studied and thereby the various theoretical models of exotic nuclei will be tested.Comment: 26 pages, 11 figures, 3 tables, accepted for publication in Phys. Rev.

On Free-Electron Laser Growing Modes and their Bandwidth

Free-electron lasers play an increasing role in science, from generating unique femtosecond X- ray pulses for single short recording of the protein structures to amplifying feeble interactions in advanced cooling systems for high-energy hadron colliders. While modern Free-electron laser codes can describe their amplification mechanism, a deep analytical understanding of the mechanism is of extreme importance for a number of applications. Mode competition, their growth rates and amplification bandwidth are among the most important parameters of a free-electron laser. A dispersion relation, which defines these important characteristics, can be solved analytically only for a very few simple cases. In this letter we show that for a typical bell-shape energy distribution in electron beam there is no more that one growing mode. We also derive an analytical expression which determines the bandwidth of the free-electron laser.Comment: 4 pages, submitted to PR

Acesso das pequenas empresas russas aos mercados de contratos públicos: análise de dados

The aim of this study was to assess the current extent of participation by Russian small enterprises in regional public procurement. We discussed how legislation affects the volume of contracts awarded to small enterprises. We calculated the number of contracts per 100 small enterprises, how much the number and value of such contracts account for in the total number and value of contracts concluded with all suppliers per region, as well as what is the average value of contracts per small enterprise and the average value of one such contract. In order to ensure benchmarking for enterprises located in different regions, such enterprises were assessed on the basis of relative indicators. This study used official statistics accumulated with regard to all public procurement in the regions. The data on the number of contracts and their value for the period from 2010 to 2014 were used. For the purposes of empirical data analysis, the normal distribution probability density functions set for all the indicators in question were used. The findings of this study and the tools used for assessing the extent of participation by small enterprises in public procurement can be used when researching entrepreneurship, as well as to justify the contract system development programs in Russia. Such information is important for entrepreneurs, as it enables them to assess the feasibility and consequences of participation in public procurement.El objetivo de este estudio fue evaluar el grado actual de participación de las pequeñas empresas rusas en la contratación pública regional. Discutimos cómo la legislación afecta el volumen de contratos adjudicados a pequeñas empresas. Calculamos el número de contratos por cada 100 pequeñas empresas, cuánto representan el número y el valor de dichos contratos en el número y el valor total de los contratos celebrados con todos los proveedores por región, así como también cuál es el valor promedio de los contratos por cada pequeña empresa y el valor promedio de uno de esos contratos. Con el fin de garantizar la evaluación comparativa para las empresas ubicadas en diferentes regiones, dichas empresas se evaluaron sobre la base de indicadores relativos. Este estudio utilizó estadísticas oficiales acumuladas con respecto a todas las contrataciones públicas en las regiones. Se utilizaron los datos sobre el número de contratos y su valor para el período de 2010 a 2014. A los efectos del análisis de datos empíricos, se utilizaron las funciones de densidad de probabilidad de distribución normal establecidas para todos los indicadores en cuestión. Las conclusiones de este estudio y las herramientas utilizadas para evaluar el grado de participación de las pequeñas empresas en la contratación pública se pueden utilizar al investigar el espíritu empresarial, así como para justificar los programas de desarrollo de sistemas contractuales en Rusia. Dicha información es importante para los empresarios, ya que les permite evaluar la viabilidad y las consecuencias de la participación en la contratación pública.O objetivo deste estudo foi avaliar o atual grau de participação das pequenas empresas russas nas compras públicas regionais. Discutimos como a legislação afeta o volume de contratos concedidos a pequenas empresas. Nós calculamos o número de contratos por 100 pequenas empresas, que representam o número eo valor desses contratos no número total eo valor total dos contratos com todos os fornecedores por região, bem como o que o valor médio de contratos para cada empresa de pequeno porte e o valor médio de um desses contratos. Para garantir benchmarking para empresas localizadas em diferentes regiões, essas empresas foram avaliadas com base em indicadores relativos. Este estudo utilizou estatísticas oficiais acumuladas em relação a todas as compras públicas nas regiões. Foram utilizados os dados sobre o número de contratos e seu valor para o período de 2010 a 2014. Para fins de análise empírica dos dados, foram utilizadas as funções de densidade de probabilidade de distribuição normal estabelecidas para todos os indicadores em questão. As conclusões deste estudo e os instrumentos utilizados para avaliar o grau de participação das pequenas empresas nos contratos públicos podem ser utilizados na investigação do empreendedorismo, bem como para justificar os programas de desenvolvimento de sistemas contratuais na Rússia. Esta informação é importante para os empresários, pois permite avaliar a viabilidade e as consequências da participação em contratos públicos

PosterVote:expanding the action repertoire for local political activism

Online and digital technologies support and extend the action repertoires of localized social movements. In this paper we examine the ways by which digital technologies can support ‘on-the-ground ’ activist communities in the development of social movements. After identifying some of the challenges of deploying conventional voting and consultation technologies for activism, we examine situated political action in local communities through the design and deployment of a low-cost community voting prototype, PosterVote. We deploy PosterVote in two case studies with two local community organizations identifying the features that supported or hindered grassroots democratic practices. Through interviews with these communities, we explore the design of situated voting systems to support grassroots democratic practices and participation within an ecology of social action. Author Keywords Democracy; activism; participation; e-votin