1,721,284 research outputs found
Cosmic Rays observed by AMS-02: Main results obtained after 5 years of flight
Full text linkThe Alpha Magnetic Spectrometer (AMS-02) is a state-of-the-art particle physics detector which operates onboard the International Space Station since May 2011. The main goals of the AMS-02 project are the indirect search of dark matter, the search of primordial antimatter, and the determination of the cosmic ray energy spectra and composition at the TeV scale. In these proceedings, the main results achieved by AMS-02 in 5 years of operations will be presented and discussed
Imporre il ricordo del nemico interno. Sulle colonne infami nell’Italia moderna
No full textIl contributo riflette sull'impiego di colonne infami nell'Italia moderna come esercizio di delegittimazione e demonizzazione della memoria di nemici interni alle città
Electron/proton separation and analysis techniques used in the AMS-02 (e++e−) flux measurement
No full textAbstractAMS-02 is a large acceptance cosmic ray detector which has been installed on the International Space Station (ISS) in May 2011, where it is collecting cosmic rays up to TeV energies. The search for Dark Matter indirect signatures in the rare components of the cosmic ray fluxes is among the main objectives of the experiment. AMS-02 is providing cosmic electrons and positrons data with an unprecedented precision. This is achieved by means to the excellent hadron/electron separation power obtained combining the independent measurements from the Transition Radiation Detector, electromagnetic Calorimeter and Tracker detectors. In this contribution we will detail the analysis techniques used to distinguish electrons from the hadronic background and show the in-flight performances of these detectors relevant for the electron/positron measurements
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Metals in organic syntheses. V. The Gattermann-Koch synthesis of aromatic aldehydes promoted by CuCl(PPh3)n(n = 0,1 or 3). Is the cuprous complex necessary in the synthesis of tolualdehyde?
No full textThe use of CuCl(PPh3) in place of CuCl in the Gattermann-Koch synthesis slightly improves the yield of PhCHO but
lowers the yield of tolualdehyde. The poorest yields are obtained in the presence of CuCl(PPh3)3. The formation of
tolualdehyde from toluene and CO in the presence of AlCl3 and HCl is faster in the presence of CuCl, but higher yields
are obtained in its absence and using an excess of hydrocarbon. In competitive expts. carried out using benzene and
toluene together in equimol. amts., only tolualdehyde was formed, supporting the view that an electrophilic substitution is
involved
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Analysis of point mutations in HPRT mutant T-lymphocytes derived from coke-oven workers.
No full textWe studied mutations in exon 3 of the hypoxanthine-guanine phosphoribosyltransferase (HPRT) locus in 113 6-thioguanine-resistant T-cell clones derived from coke-oven workers and control subjects in order to analyse possible changes in the mutational spectrum associated with the exposure to polycyclic aromatic hydrocarbons (PAHs). In 99 mutants, HPRT exon 3 was analysed by means of genomic polymerase chain reaction (PCR) and single-strand conformation polymorphism (SSCP). Products for which SSCP indicated the presence of a mutation were further analysed by DNA sequencing. In addition, HPRT cDNA from 14 clones was analysed by reverse transcription (RT) PCR and DNA sequencing. In total, 18/113 mutants (16%) had a mutation in exon 3. This frequency was similar in PAH-exposed (9/57) and non-exposed (9/56) subjects. Base substitutions caused 14 mutations at 13 different sites. Three +/- 1 bp frameshifts and one 6 bp deletion were identified. No significant differences between PAH-exposed and non-exposed workers were observed in this limited mutational spectrum. These results indicate that deletions/insertions at the HPRT exon 3 account for 22% of the mutations, and base substitutions for 78%
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