579 research outputs found
An unusual differential diagnosis of penile warts: metastases from rectal carcinoma
No full textPatients with penile lesions, such as virally induced papillomata, frequently present to genitourinary medicine clinics and general practitioners. Their diagnosis is usually based on clinical observation and biopsy is not generally undertaken. Penile lesions may rarely have a more sinister aetiology and represent metastatic spread from solid tumours arising at distant sites. Penile metastases arise most frequently from genitourinary cancers (prostate, bladder and kidney), but may also arise from tumours of the large bowel; other primary sites are extremely uncommon. We report the case of a patient presenting with penile metastases from rectal carcinoma arising during third-line chemotherapy for metastatic diseas
Normal subgroups generated by a single pure element in quaternion algebras
No full textAbstractLet D be a quaternion division algebra whose center is an arbitrary infinite field K of characteristic ≠2, and let e∈D be a pure quaternion. Hence, by definition, e∈D∖K and e2∈K. We show that if the characteristic of K is >2, then D×/〈eD×〉 is abelian-by-nilpotent-by-abelian. Note that by [A.S. Rapinchuk, L. Rowen, Y. Segev, Nonabelian free subgroups in homomorphic images of valued quaternion division algebras, Proc. Amer. Math. Soc., in press] this result is false in characteristic zero. As a consequence we show that the Whitehead group W(G,k), where G is an absolutely simple simply connected algebraic group of type D43,6 defined over a field k of odd characteristic and of k-rank 1, is abelian-by-nilpotent-by-abelian
Figure 1 in Phenotypic Convergence in Genetically Distinct Lineages of a Rhinolophus Species Complex (Mammalia, Chiroptera)
No full textFigure 1. The distribution of R. darlingi (shaded areas) and sample localities (symbols). Squares = eastern R. darlingi; Circles (southern lineage) and triangles (northern lineage) = western R. darlingi (R. damarensis; Fig. 2). TM 9474 = holotype R. d. damarensis Namibia), TM 2476 = holotype of R. d. barbetonensis South Africa. doi: 10.1371/journal.pone.0082614.g001Published as part of David S. Jacobs, Hassan Babiker, Anna Bastian, Teresa Kearney, Rowen van Eeden & Jacqueline M. Bishop, 2013, Phenotypic Convergence in Genetically Distinct Lineages of a Rhinolophus Species Complex (Mammalia, Chiroptera), pp. 1-16 in PLoS ONE 8 (12) on page 3, DOI: doi:10.1371/journal.pone.0082614, http://zenodo.org/record/426535
A Note on Rowen and Weyant,"Reducing the Economic Impacts of Oil Supply Interruptions: An International Perspective"
No full textHenry Rowen and John Weyant (1982) commit the classic error of trying to answer an important policy question with tools that do not fit the job. Nor does their care in attaching explicit caveats to their conclusions overcome the fact that the limitations of their approach are serious. The question of oil supply disruptions and their potential economic impact is indeed important, and it remains so despite slack oil markets. Policymakers may yet be faced with situations that require them to decide quickly on the advisability of emergency tariffs and other such measures; and they will need reasonable assurances that the caveats analysts attach to policy recommendations do not overwhelm the recommendations themselves. Just such a danger is inherent in the inappropriate application of models and the application of inappropriate models.
Ruth Halle Rowen : Symphonic and Chamber Music Score and Parts Bank Thematic Catalogue of the Barry S. Brook Facsimile Archive of 18th and early 19th-century Autographs, Manuscripts, and Printed Copies at the Ph. D. Program in Music of the Graduate School of the City University of New York, (Coll. «Thematic Catalogues ») 1996
No full textAutexier Philippe A. Ruth Halle Rowen : Symphonic and Chamber Music Score and Parts Bank Thematic Catalogue of the Barry S. Brook Facsimile Archive of 18th and early 19th-century Autographs, Manuscripts, and Printed Copies at the Ph. D. Program in Music of the Graduate School of the City University of New York, (Coll. «Thematic Catalogues ») 1996. In: Dix-huitième Siècle, n°29, 1997. Le vin, sous la direction de Jean Bart et Élisabeth Wahl. p. 708
Linear algebra over T-pairs
No full textPreprint arXiv:2310.05257This paper treats linear algebra over a semiring pair, in a wide range of applications to tropical algebra and related areas such as hyperrings and fuzzy rings. First we present a more general category of pairs with their morphisms, called ``weak morphisms,'' paying special attention to supertropical pairs, hyperpairs, and the doubling functor. Then we turn to matrices and the question of whether the row rank, column rank, and submatrix rank of a matrix are equal. Often the submatrix rank is less than or equal to the row rank and the column rank, but there is a counterexample to equality, discovered some time ago by the second author, which we provide in a more general setting (``pairs of the second kind'') that includes the hyperfield of signs. Additional positive results include a version of Cramer's rule, and we find situations when equality holds, encompassing results by Akian, Gaubert, Guterman, Izhakian, Knebusch, and Rowen. We pay special attention to the question of whether vectors of length need be dependent. At the end, we introduce a category with stronger morphisms, that preserve a surpassing relation
Linear algebra over T-pairs
No full textPreprint arXiv:2310.05257This paper treats linear algebra over a semiring pair, in a wide range of applications to tropical algebra and related areas such as hyperrings and fuzzy rings. First we present a more general category of pairs with their morphisms, called ``weak morphisms,'' paying special attention to supertropical pairs, hyperpairs, and the doubling functor. Then we turn to matrices and the question of whether the row rank, column rank, and submatrix rank of a matrix are equal. Often the submatrix rank is less than or equal to the row rank and the column rank, but there is a counterexample to equality, discovered some time ago by the second author, which we provide in a more general setting (``pairs of the second kind'') that includes the hyperfield of signs. Additional positive results include a version of Cramer's rule, and we find situations when equality holds, encompassing results by Akian, Gaubert, Guterman, Izhakian, Knebusch, and Rowen. We pay special attention to the question of whether vectors of length need be dependent. At the end, we introduce a category with stronger morphisms, that preserve a surpassing relation
Linear algebra over T-pairs
No full textPreprint arXiv:2310.05257This paper treats linear algebra over a semiring pair, in a wide range of applications to tropical algebra and related areas such as hyperrings and fuzzy rings. First we present a more general category of pairs with their morphisms, called ``weak morphisms,'' paying special attention to supertropical pairs, hyperpairs, and the doubling functor. Then we turn to matrices and the question of whether the row rank, column rank, and submatrix rank of a matrix are equal. Often the submatrix rank is less than or equal to the row rank and the column rank, but there is a counterexample to equality, discovered some time ago by the second author, which we provide in a more general setting (``pairs of the second kind'') that includes the hyperfield of signs. Additional positive results include a version of Cramer's rule, and we find situations when equality holds, encompassing results by Akian, Gaubert, Guterman, Izhakian, Knebusch, and Rowen. We pay special attention to the question of whether vectors of length need be dependent. At the end, we introduce a category with stronger morphisms, that preserve a surpassing relation
Linear algebra over T-pairs
No full textThis paper treats linear algebra over a semiring pair, in a wide range of
applications to tropical algebra and related areas such as hyperrings and fuzzy
rings. First we present a more general category of ``pairs'' with their
morphisms, called ``weak morphisms,'' paying special attention to supertropical
pairs, hyperpairs, and the doubling functor. Then we turn to matrices and the
question of whether the row rank, column rank, and submatrix rank of a matrix
are equal. Often the submatrix rank is less than or equal to the row rank and
the column rank, but there is a counterexample to equality, discovered some
time ago by the second author, which we provide in a more general setting
(``pairs of the second kind'') that includes the hyperfield of signs.
Additional positive results include a version of Cramer's rule, and we find
situations when equality holds, encompassing results by Akian, Gaubert,
Guterman, Izhakian, Knebusch, and Rowen. We pay special attention to the
question of whether vectors of length need be dependent. At the end,
we introduce a category with stronger morphisms, that preserve a surpassing
relation.Comment: 46 p
Binary Choice Health State Valuation and Mode of Administration: Head-to-Head Comparison of Online and CAPI
No full textThis article is made available open access through funding by the Medical Research Council. It is shared under a Creative Commons licence (http://creativecommons.org/licenses/by/3.0/). Copyright @ 2013, International Society for Pharmacoeconomics and Outcomes Research (ISPOR).Background - Health state valuation exercises can be conducted online, but the quality of data generated is unclear.
Objective - To investigate whether responses to binary choice health state valuation questions differ by administration mode: online versus face to face.
Methods - Identical surveys including demographic, self-reported health status, and seven types of binary choice valuation questions were administered in online and computer-assisted personal interview (CAPI) settings. Samples were recruited following procedures employed in typical online or CAPI studies. Analysis included descriptive comparisons of the distribution of responses across the binary options and probit regression to explain the propensity to choose one option across modes of administration, controlling for background characteristics.
Results - Overall, 422 (221 online; 201 CAPI) respondents completed a survey. There were no overall age or sex differences. Online respondents were educated to a higher level than were the CAPI sample and general population, and employment status differed. CAPI respondents reported significantly better general health and health/life satisfaction. CAPI took significantly longer to complete. There was no effect of the mode of administration on responses to the valuation questions, and this was replicated when demographic differences were controlled.
Conclusions - The findings suggest that both modes may be equally valid for health state valuation studies using binary choice methods (e.g., discrete choice experiments). There are some differences between the observable characteristics of the samples, and the groups may differ further in terms of unobservable characteristics. When designing health state valuation studies, the advantages and disadvantages of both approaches must be considered.MRC Methodology Programm
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