1,721,005 research outputs found
Mutations in the NDUFS4 gene of mitochondrial complex I alter stability of the splice variants
No full textThe effect on the stability of alternative transcripts of different mutations of the NDUFS4 gene in patients with Leigh syndrome with complex I deficiency is presented. Normally, two NDUFS4 splice variants are degraded by nonsense mediated mRNA decay (NMD) while a third form does not trigger NMD degradation. In a patient with a premature termination codon in exon 1, all the three splice variants are up-regulated. The present is the first case of a nonsense mutation leading to the abrogation of NMD, which can represent an additional event to be considered in the evaluation of clinically relevant mutations. (c) 2005 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved
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
Presentazione atipica di neuropatia ottica di leber
No full textPresentazione atipica di neuropatia ottica di leber
Di Maggio C 1
, Nardecchia F 1
, Carrozzo R 3
, Pucci C1
, Mattiucci C4
, Varrasso G 4
, De Negri A 2
,
Plateroti R 5
, Torraco A 3
, Bertini E 3
, Leuzzi V 1
, Moramarco A 5
1DAI Neurosc e Sal Ment, Univ Sapienza, Roma, 2UOC Oculistica, Osp San Cam Forl, Roma, 3Un
Mal Musc e Neurodeg, OPBG, Roma, 4DAI Mat Infant e Sc Urol, Univ Sapienza, Roma, 5DAI Testa
Collo, Oftalm, Univ Sapienza, Roma
INTRODUZIONE/BACKGROUND: La neuropatia ottica ereditaria di Leber (LHON) è una
malattia mitocondriale a trasmissione matrilineare, a penetranza incompleta e insorgenza tra i 15 e i
35 anni, caratterizzata da deficit binoculare del visus, acuto/subacuto, simultaneo o sequenziale.
L’esordio in età infantile è raro.
METODI / PAZIENTI: Segnaliamo un bambino di 12 anni che ha manifestato in pieno benessere
un deficit acuto del visus (OD 4/10, OS 6/10) e concomitante congiuntivite di ndd.Nonna e cugino
sulla linea materna con pregressa neuropatia ottica di ndd, in un caso regredita spontaneamente. Il
bambino ha sofferto di epilessia idiopatica, in remissione dall’età di 11 anni. L’esame neurooftalmologico all’esordio mostrava assenza di deficit pupillare afferente; FOO: papille ottiche
diffusamente rilevate, teleangectasie presenti tra le fibre ispessite, vasi venosi congesti, piccole
emorragie lungo le fibre del polo superiore (OD) e al polo infero-temporale (OS). Ishihara alterato.
Scotoma centrocecale bilateralmente. OCT: ispessimento dello strato delle fibre nervose e del nervo
ottico bilateralmente, riduzione dello strato delle cellule ganglionari asimmetrico (OD>OS).
Fluorangiografia: tenue diffusione papillare nelle fasi tardive, modesto turgore diffuso dei vasi
venosi, papilla ottica a margini sfumati, congestione dei grossi vasi, rete capillare accentuata ed
ectasica. PEV Pattern: latenza aumentata, in OD a basse frequenze, in OS a medie frequenze. Nella
norma: RMN encefalo (mdc), PEV Flash, ERG, CSF (pressione liquorale, esame chimico-fisico, Ab
antiacquaporina4 e anti-MOG), sierologia per EBV, CMV, HSV1-2, Morbillo, VZV, Borrelia.
RISULTATI: La diagnosi è stata effettuata mediante sequenziamento con metodo Sanger che ha
evidenziato la mutazione T14484C nel gene MT-ND6 in omoplasmia.
DISCUSSIONE: Questo caso è peculiare per la presentazione atipica con un(o) (pseudo)edema
papillare che può essere causa di ritardo diagnostico e terapeutico
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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