Studies of negative ions formed by low energy electron impact

In this thesis the processes responsible for the formation of negative ions by the interaction of low energy electrons (0 to 15eV) with molecules in the gas phase have been investigated. Particular attention has been paid to the processes known as associative resonance capture and dissociative resonance capture. For a molecule AB, associative resonance capture is described by the equation AB + e → AB⁻, where the metastable molecular negative ion AB⁻ is formed by the capture of slow electrons. Dissociative resonance capture, described by the equation AB⁻ → A⁻ + B, results in the formation of a stable negative ion and can occur throughout the energy range studied. A historical review of the theoretical approach to electron-attachment is followed by detailed accounts of the most recent theoretical treatments of associative and dissociative resonance capture. The time-of-flight mass spectrometer used for this study has been described in some detail as have the experimental procedures developed. The various devices used to overcome the problems created by the broad electron energy distribution, which is due to the use of thermionically emitted electron beams, have been critically reviewed and the analytical deconvolution procedure adopted in this study has been described in detail. Autodetachment lifetimes and capture cross-sections for the associative attachment of electrons by several groups of organic and inorganic molecules have been measured and comparisons made with the predictions of the statistical theory for associative electron capture. Attempts to calculate electron affinities from this theory, using the lifetimes and cross -sections measured, met with some success for simple molecules and enabled conclusions to be made concerning the adequacy and limitations of the theoretical treatment. From studies of the electron energy dependence of negative ion formation for several groups of inorganic and organic molecules, various ionisation processes have been identified. Deconvolution of the ionisation curves has enabled accurate appearance potential data to be determined and, in many cases, allowed bond dissociation energies, electron affinities and heats of formation of various species to be evaluated

Процесс фтороаммонийной переработки высокофтористых бериллиевых концентратов

В работе приведено научное обоснование способа фтороаммонийной переработки высокофтористого бериллиевого концентрата, предложены технологические режимы переработки бериллиевого концентрата. Исследование технологического процесса и определение режимов, обеспечивающих экономически эффективную переработку концентратов, проводили на специально изготовленной опытной установке. В результате работы создана и апробирована принципиальная схема переработки бериллиевых концентратов, разработано аппаратурное оформление процесса. Приведено технико-экономическое обоснование технологии.The scientific substantiation of the processing of high-fluoride beryllium concentrates by ammonium fluoride is given in graduation thesis. Technological conditions of beryllium concentrate processing are proposed. The research of the technological process and determination of the conditions providing cost-effective processing of concentrates was carried out on a specially manufactured pilot plant. As a result of the work, a basic scheme for the processing of beryllium concentrates was developed and approved, and the hardware design of the process was developed. The feasibility study of technology is shown

Towards an Economy of Higher Education

This paper draws a distinction between ways thinking and acting, and hence of policy and practice in higher education, in terms of different kinds of economy: economies of exchange and economies of excess. Crucial features of economies of exchange are outlined and their presence in prevailing conceptions of teaching and learning is illustrated. These are contrasted with other possible forms of practice, which in turn bring to light the nature of an economy of excess. In more philosophical terms, and to expand on the picture, economies of excess are elaborated with reference, first, to the understanding of alterity in the work of Emmanuel Levinas and, second, to the idea of Dionysian intensity that is to be found in Nietzsche. In the light of critical comment on some current directions in policy and practice, the implications of these ways of thinking for the administrator, the teacher and the student in higher education are explored

The Multi-Object, Fiber-Fed Spectrographs for SDSS and the Baryon Oscillation Spectroscopic Survey

We present the design and performance of the multi-object fiber spectrographs for the Sloan Digital Sky Survey (SDSS) and their upgrade for the Baryon Oscillation Spectroscopic Survey (BOSS). Originally commissioned in Fall 1999 on the 2.5-m aperture Sloan Telescope at Apache Point Observatory, the spectrographs produced more than 1.5 million spectra for the SDSS and SDSS-II surveys, enabling a wide variety of Galactic and extra-galactic science including the first observation of baryon acoustic oscillations in 2005. The spectrographs were upgraded in 2009 and are currently in use for BOSS, the flagship survey of the third-generation SDSS-III project. BOSS will measure redshifts of 1.35 million massive galaxies to redshift 0.7 and Lyman-alpha absorption of 160,000 high redshift quasars over 10,000 square degrees of sky, making percent level measurements of the absolute cosmic distance scale of the Universe and placing tight constraints on the equation of state of dark energy. The twin multi-object fiber spectrographs utilize a simple optical layout with reflective collimators, gratings, all-refractive cameras, and state-of-the-art CCD detectors to produce hundreds of spectra simultaneously in two channels over a bandpass covering the near ultraviolet to the near infrared, with a resolving power R = \lambda/FWHM ~ 2000. Building on proven heritage, the spectrographs were upgraded for BOSS with volume-phase holographic gratings and modern CCD detectors, improving the peak throughput by nearly a factor of two, extending the bandpass to cover 360 < \lambda < 1000 nm, and increasing the number of fibers from 640 to 1000 per exposure. In this paper we describe the original SDSS spectrograph design and the upgrades implemented for BOSS, and document the predicted and measured performances.Comment: 43 pages, 42 figures, revised according to referee report and accepted by AJ. Provides background for the instrument responsible for SDSS and BOSS spectra. 4th in a series of survey technical papers released in Summer 2012, including arXiv:1207.7137 (DR9), arXiv:1207.7326 (Spectral Classification), and arXiv:1208.0022 (BOSS Overview

POT1 mutations predispose to familial melanoma

Deleterious germline variants in CDKN2A account for around 40% of familial melanoma cases, and rare variants in CDK4, BRCA2, BAP1 and the promoter of TERT have also been linked to the disease. Here we set out to identify new high-penetrance susceptibility genes by sequencing 184 melanoma cases from 105 pedigrees recruited in the UK, The Netherlands and Australia that were negative for variants in known predisposition genes. We identified families where melanoma cosegregates with loss-of-function variants in the protection of telomeres 1 gene (POT1), with a proportion of family members presenting with an early age of onset and multiple primary tumors. We show that these variants either affect POT1 mRNA splicing or alter key residues in the highly conserved oligonucleotide/oligosaccharide-binding (OB) domains of POT1, disrupting protein-telomere binding and leading to increased telomere length. These findings suggest that POT1 variants predispose to melanoma formation via a direct effect on telomeres.D.J.A., C.D.R.-E., Z.D., J.Z.L., J.C.T., M.P. and T.M.K. were supported by Cancer Research UK and the Wellcome Trust (WT098051). C.D.R.-E. was also supported by the Consejo Nacional de Ciencia y Tecnología of Mexico. K.A.P. and A.M.D. were supported by Cancer Research UK (grants C1287/A9540 and C8197/A10123) and by the Isaac Newton Trust. N.K.H. was supported by a fellowship from the National Health and Medical Research Council of Australia (NHMRC). L.G.A. was supported by an Australia and New Zealand Banking Group Limited Trustees PhD scholarship. A.L.P. is supported by Cure Cancer Australia. The work was funded in part by the NHMRC and Cancer Council Queensland. The work of N.A.G. was in part supported by the Dutch Cancer Society (UL 2012-5489). M.H., J.A.N.-B. and D.T.B. were supported by Cancer Research UK (programme awards C588/A4994 and C588/A10589 and the Genomics Initiative). C.L.-O., A.J.R. and V.Q. are funded by the Spanish Ministry of Economy and Competitiveness through the Instituto de Salud Carlos III (ISCIII), the Red Temática de Investigación del Cáncer (RTICC) del ISCIII and the Consolider-Ingenio RNAREG Consortium. C.L.-O. is an investigator with the Botín Foundation.This is the author accepted manuscript. The final version is available from NPG via http://dx.doi.org/10.1038/ng.294

Estimating CDKN2A mutation carrier probability among global familial melanoma cases using GenoMELPREDICT

Background: Although rare in the general population, highly penetrant germline mutations in CDKN2A are responsible for 5%-40% of melanoma cases reported in melanoma-prone families. We sought to determine whether MELPREDICT was generalizable to a global series of families with melanoma and whether performance improvements can be achieved. Methods: In total, 2116 familial melanoma cases were ascertained by the international GenoMEL Consortium. We recapitulated the MELPREDICT model within our data (GenoMELPREDICT) to assess performance improvements by adding phenotypic risk factors and history of pancreatic cancer. We report areas under the curve (AUC) with 95% confidence intervals (CIs) along with net reclassification indices (NRIs) as performance metrics. Results: MELPREDICT performed well (AUC 0.752, 95% CI 0.730-0.775), and GenoMELPREDICT performance was similar (AUC 0.748, 95% CI 0.726-0.771). Adding a reported history of pancreatic cancer yielded discriminatory improvement (P &lt; .0001) in GenoMELPREDICT (AUC 0.772, 95% CI 0.750-0.793, NRI 0.40). Including phenotypic risk factors did not improve performance. Conclusion: The MELPREDICT model functioned well in a global data set of familial melanoma cases. Adding pancreatic cancer history improved model prediction. GenoMELPREDICT is a simple tool for predicting CDKN2A mutational status among melanoma patients from melanoma-prone families and can aid in directing these patients to receive genetic testing or cancer risk counseling