1,720,974 research outputs found
On point interactions realised as Ter-Martyrosyan-Skornyakov operators
No full textFor quantum systems of zero-range interaction we discuss the mathematical scheme within which modelling the two-body interaction by means of the physically relevant ultra-violet asymptotics known as the "Ter-Martirosyan-Skornyakov condition" gives rise to a self-adjoint realisation of the corresponding Hamiltonian. This is done within the self-adjoint extension scheme of Krein, Visik, and Birman. We show that the Ter-Martirosyan-Skornyakov asymptotics is a condition of self-adjointness only when is imposed in suitable functional spaces, and not just as a pointwise asymptotics, and we discuss the consequences of this fact on a model of two identical fermions and a third particle of different nature
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
Ataxia-without-telangiectasia in two sisters with rearrangements of chromosomes 7 and 14.
No full textTwo sisters, 11 and 9 years old respectively, had the clinical features of a progressive neurological disorder similar to the ataxia-telangiectasia (AT) syndrome. The two patients have ataxia and chromosome instability with rearrangements of chromosomes 7 and 14 but no telangiectasia, nor the range of immunological anomalies typical of AT. Comparison with similar cases from the literature leads to the conclusion that either there is a specific disorder characterized by ataxia-without-telangiectasia and with the same cytogenetic pattern of AT, or AT shows a wider variability of phenotypic expression than thought befor
ATAXIA WITHOUT TELANGIECTASIA IN TWO SISTERS WITH REARRANGEMENTS OF CHROMOSOMES 7 AND 14.
No full textTwo sisters, 11 and 9 years old respectively, had the clinical features of a progressive neurological disorder similar to the ataxia-telangiectasia (AT) syndrome. The two patients have ataxia and chromosome instability with rearrangements of chromosomes 7 and 14 but no telangiectasia, nor the range of immunological anomalies typical of AT. Comparison with similar cases from the literature leads to the conclusion that either there is a specific disorder characterized by ataxia-without-telangiectasia and with the same cytogenetic pattern of AT, or AT shows a wider variability of phenotypic expression than thought before
Ataxia-telangiectasia: clinical cytogenetics and immunological aspects in four atypical cases
No full textVariations 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
Fractional powers and singular perturbations of quantum differential Hamiltonians
No full textWe consider the fractional powers of singular (point-like) perturbations of the Laplacian and the singular perturbations of fractional powers of the Laplacian, and we compare two such constructions focusing on their perturbative structure for resolvents and on the local singularity structure of their domains. In application to the linear and non-linear Schrodinger equations for the corresponding operators, we outline a programme of relevant questions that deserve being investigated. Published by AIP Publishing
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
Clinical cytogenetic and immunological aspects in 4 cases resembling ataxia telangiectasia.
No full textFour cases resembling ataxia telangiectasia, all characterized by the absence of telangiectasias, are presented. Two are sisters while the other 2 are sporadic cases. The 2 sisters, aged 14 and 12 years, present a progressive neurological disease similar to that characterizing the Louis-Bar syndrome. The clinical picture in 1 of the sporadic cases, a girl aged 13 years, differs from the typical ataxia telangiectasia in having bilateral pyramidal signs in the lower limbs. The last case, a girl aged 8 years, presents an atypical clinical pattern characterized by a severe mental retardation, quite modest cerebellar signs and absence of involuntary movements. The results of the immunological and cytogenetic investigations are presented and discussed
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