1,720,959 research outputs found
Genetics of hearing loss (from congenital forms to presbycusis)
No full textSince the identification of the first deafness gene in the '90s, a relevant number of genes have been identified. This finding led to a significant increase on the molecular knowledge of the processes responsible for hearing and balance and of the corresponding pathological mechanisms. But there is still a long way to go and many genes remain to be identified. The elucidation of the exact function of genes for which only a putative function has been hypothesized and of genes with an unknown function, remains a great challenge. In this chapter an up-to-day overview on the genetics of hearing loss is provided to the reader
Contemporary genetics-based diagnostics of male infertility
No full textIntroduction Thousands of genes are implicated in spermatogenesis, testicular development and endocrine regulation of testicular function. The genetic contribution to male infertility is therefore considerable, and basic and clinical research in the last years found a number of genes that could potentially be used in clinical practice. Research has also been pushed by new technologies for genetic analysis. However, genetic analyses currently recommended in standard clinical practice are still relatively few. Areas covered We review the genetic causes of male infertility, distinguishing those already approved for routine clinical application from those that are still not supported by adequate clinical studies or those responsible for very rare cause of male infertility. Genetic causes of male infertility vary from chromosomal abnormalities to copy number variations (CNVs), to single-gene mutations. Expert opinion Clinically, the most important aspect is related to the correct identification of subjects to be tested and the right application of genetic tests based on clear clinical data. A correct application of available genetic tests in the different forms of male infertility allows receiving a better and defined diagnosis, has an important role in clinical decision (treatment, prognosis), and allows appropriate genetic counseling especially in cases that should undergo assisted reproduction techniques
GJB2 and GJB6 genes and the A1555G mitochondrial mutation are only minor causes of nonsyndromic hearing loss in the Qatari population
No full textOBJECTIVE:
This study reports results from the first survey of the genetic causes of nonsyndromic sensorineural hearing loss (NSHHL) in the Qatari population. DESIGN AND STUDY SAMPLES: Data were collected from 126 Qatari patients (58 males and 68 females) belonging to inbred families (56%), showing an autosomal recessive pattern of inheritance (96%). Fifty-three patients were less than 10 years old, 55 in the age range of 10 to 20 years, while 18 were aged between 20 and 30 years. All subjects had moderate to severe sensorineural hearing loss and were screened for GJB2 mutations, GJB6 deletion, and for A1555G mitochondrial mutation.
RESULTS:
Four patients were homozygous and one was heterozygous for c.35delG; five were homozygous for the IVS1 + 1G C. Only 8.3% of the pathogenic alleles were detected. No patients were positive for GJB6 deletion or for A1555G .
CONCLUSIONS:
These findings: (1) demonstrate that GJB2, GJB6 deletion and A1555G mutation account for a minor proportion of NSHHL in the Qatari population, (2) further strengthen the need to search for causative genes, (3) clearly contribute to establishing preventive strategies for NSHHL in Qatar and in the Gulf are
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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