1,721,104 research outputs found
Retrospective and prospective epidemiological studies of 1,500 karyotyped spontaneous human abortions
No full text
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
Detailed clinical and molecular study of 20 females with Xq deletions with special reference to menstruation and fertility
No full textA study of cryptic terminal chromosome rearrangements in recurrent miscarriage couples detects unsuspected acrocentric pericentromeric abnormalities
No full textFifty chromosomally normal couples with three or more miscarriages were examined using fluorescent in situ hybridisation (FISH) and a library of subtelomere-specific probes together with alphoid repeats mapping to the acrocentric centromeres. Six abnormalities were found. Firstly, a cryptic reciprocal subtelomere translocation between the long arm of a chromosome 3 and the short arm of a chromosome 10. The other five cryptic abnormalities involved the acrocentric chromosome pericentromeric regions and in one case also Yp. Two patients had a rearranged chromosome 13, where the centromeric region was found to be derived from the short arm, centromere and proximal long arm of chromosome 15. Another two patients had a derived chromosome 22, where the centromere was replaced by two other centromeres, one derived from chromosome 14 and the other from either chromosome 13 or 21, while one patient had the subtelomere region of Yp translocated onto the short arm of a chromosome 21. These abnormalities may be the underlying cause of the recurrent miscarriages, because they may result in abnormal pairing configurations at meiosis leading to non-disjunction of whole chromosomes at metaphase I. The frequency of rearrangements seen in the recurrent miscarriage patient population was significantly different from that in the control group (P=0.0096, Fisher's exact test) due to the acrocentric pericentromeric abnormalities
Breakpoint mapping and haplotype analysis of three reciprocal translocations identify a novel recurrent translocation in two unrelated families: t(3;11) (p16.2;p15.4)
No full textThe majority of constitutional reciprocal translocations appear to be unique rearrangements arising from independent events. However, a small number of translocations are recurrent, most significantly the t(11;22)(q23;q11). Among large series of translocations there may be multiple independently ascertained cases with the same cytogenetic breakpoints. Some of these could represent additional recurrent rearrangements, alternatively they could be identical by descent (IBD) or have subtly different breakpoints when examined under higher resolution. We have used molecular breakpoint mapping and haplotyping to determine the origin of three pairs of reciprocal constitutional translocations, each with the same cytogenetic breakpoints. FISH mapping showed one pair to have different breakpoints and thus to be distinct rearrangements. Another pair of translocations were IBD with identical breakpoint intervals and highly conserved haplotypes on the derived chromosomes. The third pair, t(4;11)(p16.2;p15.4), had the same breakpoint intervals by aCGH and fosmid mapping but had very different haplotypes, therefore they represent a novel recurrent translocation. Unlike the t(11;22)(q23;q11), the formation of the t(4;11)(p16.2;p15.4) may have involved segmental duplications and sequence homology at the breakpoints. Additional examples of recurrent translocations could be identified if the resources were available to study more translocations using the approaches described here. However, like the t(4;11)(p16.2;p15.4), such translocations are likely to be rare with the t(11;22) remaining the only common recurrent constitutional reciprocal translocatio
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
- …
