378 research outputs found
Letter from Francois E. Matthes to Carl Hayden
No full textLetter from François E. Mathes to Carl T. Hayden about maps of the Grand Canyon
Tagging of Biomedical Articles on CiteULike: A Comparison of User, Author and Professional Indexing
No full textThis paper examines the context of online indexing from the viewpoint of three different groups: users, authors, and professional indexers. User tags, author keywords and descriptors were collected from academic journal articles, which were both indexed in Pubmed and tagged on CiteULike, and analysed. Descriptive statistics, informetric measures, and thesaural term comparison shows that there are important differences in the use of keywords between the three groups in addition to similarities which can be used to enhance support for search and browse. While tags and author keywords were found that matched descriptors exactly, other terms which did not match but provided important expansion to the indexing lexicon were found. These additional terms could be used to enhance support for searching and browsing in article databases as well as to provide invaluable data for entry vocabulary and emergent terminology for regular updates to indexing systems. Additionally, the study suggests that tags support organisation by association to task, projects and subject while making important connections to traditional systems which classify into subject categories
ARCADE: Description of the project and setup of the Lidar/AMT system
No full textThe ARCADE (Atmospheric Research for Climate and Astroparticle DEtection) project is a 3 years project funded by MIUR, that aims to study the aerosol attenuation of UV light in atmosphere using multiple instruments and techniques, as those commonly used in the cosmic rays community: elastic Lidar, Raman Lidar, side-scattering measurements using a distant laser source. All measurements will be acquired on the same air mass at the same time, in a semi-desertic site near Lamar, Colorado (U.S.). For each instrument, multiple analysis techniques will be tested: the target is a better comprehension of the systematics and limits of applicability of each method. The system is composed by a Lidar (elastic+Raman), fully designed and built within this project, and by the Atmospheric Monitoring Telescope (AMT), a telescope for the detection of UV light owned by the Colorado School of Mines. The setup of the two instruments is described in detail here. The project is presently in its third year: the Lidar system has been tested at the University of L'Aquila in February 2014 before shipment to the U.S., and the AMT has been recently reinstalled and tested in Lamar (May 2014). In June/July 2014 the ARCADE group will work out the final setup of the Lidar+AMT system in Lamar and will begin data acquisition
Following Cochrane review protocols to completion 10 years later: a retrospective cohort study and author survey
No full textWe analyzed patterns of publication of Cochrane review protocols (CRPs)
Matrix semigroups with commutable rank
No full textWe focus on matrix semigroups (and algebras) on which rank is commutable [rank(AB) = rank(BA)]. It is shown that in a number of cases (for example, in dimensions less than 6), but not always, commutativity of rank entails permutability of rank [rank(A(1)A(2)...A(n)) = rank(A(sigma(1))A(sigma(2))... A(sigma(n)))]. It is shown that a commutable-rank semigroup has a natural decomposition as a semi-lattice of semigroups that have a simpler structure. While it is still unknown whether commutativity of rank entails permutability of rank for algebras, the question is reduced to the case of algebras of nilpotents.PT: J; CR: ANDERSON FW, 1992, GRADUATE TEXTS MATH ANDO T, 1987, LINEAR ALGEBRA APPL, V90, P165 GANTMACHER FR, 1937, COMPOS MATH, P445 HORN RA, 1990, MATRIX ANAL LEVITZKI J, 1931, MATH ANN, V105, P620 LIVSHITS L, 1998, J OPERAT THEOR, V40, P35 OKNINSKI J, 1998, SERIES ALGEBRA, V6 PRASOLOV VV, 1994, PROBLEMS THEOREMS LI RADJAVI H, 2000, SIMULTANEOUS TRIANGU WHITNEY AM, 1952, J ANAL MATH, V2, P88; NR: 10; TC: 1; J9: SEMIGROUP FORUM; PG: 29; GA: 698NQSource type: Electronic(1
User, Author and Professional Indexing in Context: An Exploration of Tagging Practices on CiteULike
No full textThis paper examines the context of online indexing from the viewpoint of three different groups: users, authors, and intermediaries. User, author and intermediary keywords were collected from journal articles tagged on CiteULike and analysed. Descriptive statistics, informetric measures, and thesaural term comparison shows that there are important differences in the context of keywords from the three groups
Comparative effectiveness of common therapies for Wilson disease: A systematic review and meta-analysis of controlled studies
No full textBACKGROUND & AIMS: Wilson disease (WD) is a rare disorder of copper metabolism. The objective of this systematic review is to determine the comparative effectiveness and safety of common treatments of WD. METHODS: We included WD patients of any age or stage and the study drugs D-penicillamine, zinc salts, trientine, and tetrathiomolybdate. The control could be placebo, no treatment, or any other treatment. We included prospective, retrospective, randomized, and non-randomized studies. We searched Medline and Embase via Ovid, the Cochrane Central Register of Controlled Trials, and screened reference lists of included articles. Where possible, we applied random-effects meta-analyses. RESULTS: The 23 included studies reported on 2055 patients and mostly compared D-penicillamine to no treatment, zinc, trientine, or succimer. One study compared tetrathiomolybdate and trientine. Post-decoppering maintenance therapy was addressed in one study only. Eleven of 23 studies were of low quality. When compared to no treatment, D-penicillamine was associated with a lower mortality (odds ratio 0.013; 95% CI 0.0010 to 0.17). When compared to zinc, there was no association with mortality (odds ratio 0.73; 95% CI 0.16 to 3.40) and prevention or amelioration of clinical symptoms (odds ratio 0.84; 95% CI 0.48 to 1.48). Conversely, D-penicillamine may have a greater impact on side effects and treatment discontinuations than zinc. CONCLUSIONS: There are some indications that zinc is safer than D-penicillamine therapy while being similarly effective in preventing or reducing hepatic or neurologic WD symptoms. Study quality was low warranting cautious interpretation of our findings
On transitive linear semigroups
No full textThis paper deals with semigroups of linear transformations which act transitively on a finite-dimensional vector space. An explicit canonical form is obtained for the semigroups which lack proper transitive left ideals. The class of such semigroups can be considered to be an extention of the class of transitive groups. It contains all minimal transitive (and hence all sharply transitive) semigroups. (C) 2000 Elsevier Science Inc. All rights reserved.PT: J; CR: FILLMORE PA, 1971, ADV MATH, V7, P254 KALSCHEUER F, 1940, ABH MATH SEM HAMBURG, V13, P413 RADJAVI H, 1973, ERGEBNISSE MATH IHRE, V77 RADJAVI H, 1997, LINEAR OPERATORS, P287 ZASSENHAUS H, 1936, ABH MATH SEM HAMBURG, V11, P187; NR: 5; TC: 2; J9: LINEAR ALGEBRA APPL; PG: 20; GA: 275MJSource type: Electronic(1
On operator bands
No full textA multiplicative semigroup of idempotent operators is called an operator band. We prove that for each K > 1 there exists an irreducible operator band on the Hilbert space l(2) which is norm-bounded by K. This implies that there exists an irreducible operator band on a Banach space such that each member has operator norm equal to 1. Given a positive integer r, we introduce a notion of weak r-transitivity of a set of bounded operators on a Banach space. We construct an operator band on l(2) that is weakly r-transitive and is not weakly (r + 1)-transitive. We also study operator bands S satisfying a polynomial identity p(A, B) = 0 for all non-zero A, B epsilon S, where p is a given polynomial in two non-commuting variables. It turns out that the polynomial p(A, B) = (AB - BA)(2) has a special role in these considerations.PT: J; CR: CONWAY JB, 1990, COURSE FUNCTIONAL AN DRNOVSEK R, 1997, STUD MATH, V125, P97 FILLMORE P, 1999, SEMIGROUP FORUM, V59, P362 GREEN JA, 1952, P CAMBRIDGE PHILOS S, V48, P35 LIVSHITS L, IN PRESS J OPERATOR LIVSHITS L, 1998, J OPERAT THEOR, V40, P35 PETRICH M, 1977, LECT SEMIGROUPS; NR: 7; TC: 0; J9: STUD MATH; PG: 10; GA: 348YKSource type: Electronic(1
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