Distinct nonequilibrium plasma chemistry of C2 affecting the synthesis of nanodiamond thin films from C2H2 (1%)/H2/Ar-rich plasmas

6 pages, 5 figures, 6 tables.We show that the concentrations of the species C2 (X 1Σg+), C2 (a 3Πu), and C2H exhibit a significant increase when the argon content grows up to 95% in medium pressure (0.75 Torr) radio frequency (rf) (13.56 MHz) produced C2H2 (1%)/H2/Ar plasmas of interest for the synthesis of nanodiamond thin films within plasma enhanced chemical vapor deposition devices. In contrast, the concentrations of CH3 and C2H2 remain practically constant. The latter results have been obtained with an improved quasianalytic space–time-averaged kinetic model that, in addition, has allowed us to identify and quantify the relative importance of the different underlying mechanisms driving the nonequilibrium plasma chemistry of C2. The results presented here are in agreement with recent experimental results from rf CH4/H2/Ar-rich plasmas and suggest that the growth of nanodiamond thin films from hydrocarbon/Ar-rich plasmas is very sensitive to the contribution of C2 and C2H species from the plasma.This work was partially funded by CICYT (Spain) under a Ramón y Cajal project and under Project No. TIC2002- 03235. One of the authors (F.J.G.V.) acknowledges a Ramón y Cajal contract from the Spanish Ministry of Science and Technology (MCYT). One of the authors (J.M.A.) acknowledges partial support from CICYT (Spain) under Project No. MAT 2002-04085-C02-02.Peer reviewe

Public health triangulation: approach and application to synthesizing data to understand national and local HIV epidemics

<p>Abstract</p> <p>Background</p> <p>Public health triangulation is a process for reviewing, synthesising and interpreting secondary data from multiple sources that bear on the same question to make public health decisions. It can be used to understand the dynamics of HIV transmission and to measure the impact of public health programs. While traditional intervention research and metaanalysis would be ideal sources of information for public health decision making, they are infrequently available, and often decisions can be based only on surveillance and survey data.</p> <p>Methods</p> <p>The process involves examination of a wide variety of data sources and both biological, behavioral and program data and seeks input from stakeholders to formulate meaningful public health questions. Finally and most importantly, it uses the results to inform public health decision-making. There are 12 discrete steps in the triangulation process, which included identification and assessment of key questions, identification of data sources, refining questions, gathering data and reports, assessing the quality of those data and reports, formulating hypotheses to explain trends in the data, corroborating or refining working hypotheses, drawing conclusions, communicating results and recommendations and taking public health action.</p> <p>Results</p> <p>Triangulation can be limited by the quality of the original data, the potentials for ecological fallacy and "data dredging" and reproducibility of results.</p> <p>Conclusions</p> <p>Nonetheless, we believe that public health triangulation allows for the interpretation of data sets that cannot be analyzed using meta-analysis and can be a helpful adjunct to surveillance, to formal public health intervention research and to monitoring and evaluation, which in turn lead to improved national strategic planning and resource allocation.</p

Accurate protocol for nanoparticles analysis (size, size distribution, concentration) by SAXS and spICPMS

International audienceSmall Angles X-Ray Scattering (SAXS) has been established as a metrological method for the determination of nanoparticles size and size distribution. Modern SAXS Laboratory experiments, by involving synchrotron-based instrumentation at lower price and very stable X-ray source, are more and more use in nanomaterials domain. In the frame of the Innanopart project we have develop a methodology for the size and concentration determination of spheric Silica nanoparticles. This protocol involves a precise sample preparation, and a set of homemade software tools for the data processing-from the acquisition, the absolute scaling, to the analysis. spICPMs is not a metrological traceable technique but has many strengths to become a useful complement of nanoparticle characterization methods such as SAXS and microscopy. It can also measure highly diluted nanoparticles suspensions which is not the case of Dynamic Light scattering (DLS) or SAXS. Finally, ICPMS analyzes inorganic ions in liquid solution in a very large range of concentration, which should allow linear diameter measurement range over at least 3 orders of magnitude by spICPMS. In this work, we confront spICPMS, as a counting technique, with SAXS in order to investigate the method and the developed protocols on a set of commercial Gold Nanoparticles

Approach to the Diversity of Dairy Farm Systems in Reunion

The impacts of economical, institutional and technical changes on farming systems’ organization and performance differ between systems depending on initial endowments, projects, organization types and productive-system management, investment opportunities, etc. As it is difficult to apprehend exhaustively individual diversity, farm modeling through typology appears as the only way to approach farming systems’ diversity in order to assess change differentiated effects and to ensure that research and development will reflect local needs and diversity. The typology, which characterizes the diversity of dairy farm systems in Reunion, results from an iterative and progressive process that combines principles from the typology à dire d’expert (i.e. based on an expert representation of the diversity) and multivariate methods. The typology was developed from surveys and interviews of farmers, and the various actors of the dairy sector: cooperatives, development agencies, local administrators, management centers, etc

Contribution to accurate Spherical Gold Nanoparticles analysis (size, size distribution) by SpICPMS and SAXS

International audienceSmall-Angles X-Ray Scattering (SAXS) has been established as a metrological method for the determination of nanoparticles size and size distribution. Modern SAXS Laboratory experiments, by involving synchrotron-based instrumentation at lower price and very stable X-ray source, are more and more used in nanomaterials domain. In the frame of the EMPIR Innanopart project, we have developed a methodology for the size, size distribution and concentration determination of spherical nanoparticles. This protocol involves a precise sample preparation, and a set of homemade software tools for the data processing-from the acquisition, the absolute scaling, to the analysis. spICPMs is not a metrological traceable technique but has many strengths to become a useful complement of nanoparticle characterization methods such as SAXS and microscopy. It can also measure highly diluted nanoparticles suspensions which is not the case of Dynamic Light scattering (DLS) or SAXS. Finally, ICPMS analyzes inorganic ions in liquid solution in a very large range of concentration, which should allow linear diameter measurement range over at least 3 orders of magnitude. In this work, we confront spICPMS with SAXS in order to investigate the method and the developed protocols on a set of commercial spherical Gold Nanoparticles. Comparison between SAXS and spIPCMS method for the determination of size of spherical Gold Nanoparticle