1,721,388 research outputs found
The solar neutrino puzzle and the vL → vR conversion hypothesis
No full textAs a possible explanation of the solar neutrino puzzle, several authors have invoked a neutrino helicity rotation (vL → vR) in the solar magnetic field, coupled to a neutrino magnetic moment. We discuss: (i) the effect on the vL → vR conversion probability of the different coherent interaction with matter of the two neutrino helicity states; (ii) the azimuthal asymmetry in the elastic v-e scattering of solar neutrinos, due to the interference between the weak and the electromagnetic amplitude. We also briefly comment on the theoretical problem posed by a neutrino magnetic moment as large as 10-10μB. © 1988
Localization of 3β-hydroxysteroid dehydrogenase in Anguilla anguilla testis
No full textThe histochemical reaction for 3 beta-hydroxysteroid dehydrogenase was applied to glutaraldehyde fixed eel testis and succesively processed for transmission electron microscopy. The reaction product was found only on the smooth endoplasmic reticulum and in the intermembrane space of mitochondria of the Leydig cells of hCG treated silver eels. The positive cytochemical reaction appears to be coupled with an enlargement of the Leydig cells and an increase of their smooth endoplasmic reticulu
Effetto della denaturazione termica delle proteine di latte su alcune caratteristiche del gelato
No full textMicroterracettes in Sabkha Oum Dba (Western Sahara, Morocco): physical and biological interactions in the formation of a surface micromorphology
No full textSmall-scale terracing (microterracettes) are surface geomorphic features that recur under a range of environmental settings, such as those existing in high to low temperature geothermal springs and in evaporitic environments, through the single or combined action of physicochemical agents and microbiological processes. Such morphology can also be observed in a confined sector of the Sabkha Oum Dba, an inland sabkha of the Western Sahara (Morocco), where field and laboratory investigations revealed that they primarilylargely depend on the accumulation of naviculoid diatoms. Through their ability of biofilm production these benthic diatoms are able to stabilize surface morphologies and make organic alveolar frameworks where precipitation of low-Mg calcite occur in areas subjected to active oxygenic photosynthesis. Because microterracettes arise in a specific set of environmental conditions, they have environmental significance and, thanks to a high fossilization potential due to mineral precipitation, they can be an effective source of bio-morphological and chemical evidence for life. The relationship with aqueous environments, considered to be widestread on Mars especially during a period of intense hydrologic activity as in the late Noachian and Esperian, make useful the understanding of surficial processes (such as the formation of microterracettes) whose formation is frequent in terrestrial analogs for Martian environments, such as ephemeral saline continental lakes (sabkhas), and related to products of bacterial and eukaryotic life, as in the case of biofilms, in search for similar life forms beyond Earth
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
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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