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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
Molecular bases of sialyl Lewis x overexpression in colon cancer
No full textSialyl Lewis x (sLex) is a well known selectin ligand involved in metastasis. The molecular bases of its overexpression in colon cancer are still unclear. Here we show that FucT-VI is the main fucosyltransferase responsible for sLex biosynthesis in colonic tissues and a major regulator of sLex expression in colon cancer because: 1) in colon cancer specimens and cell lines sLex expression correlates with the activity of a fucosyltransferase able to fucosylate 3’ sialyllactosamine (3’SLN) at a low (0.5 mM) acceptor concentration. 2) In cells transiently transfected with FucT genes only FucT-VI displays this property. 3) In normal and cancer colon, FucT-VI transcript shows the highest level of expression (about 200 fg/pg actin, vs. 30 for FucT-III, 10 for FucT-IV, <1 for FucT-V while FucT-VII was undetectable). However, neither the FucT-VI transcript nor the activity on 3’SLN are increased in cancer tissues. In normal mucosa, sLex (which can be detected upon de-acetylation), does not correlate with FucT-VI activity. This is due to the concomitant high expression of beta4GalNAcT-II, the synthase of the Sda antigen [Sia alpha2,3(GalNAc beta1,4)Galbeta1,4GlcNAc], which competes with fucosyltransferases for 3’-sialylated type 2 chains and is downregulated in colon cancer. In fact, in normal mucosa sLex expression correlates with the ratio between the activities of FucT-VI and that of beta4GalNAcT-II. These findings explain why sLex antigen overexpression in cancer is not necessarily related to FucT-VI overexpression, and point to the balance between FucT-VI and beta4GalNAcT-II as a pivotal regulator of sLex in colon
IN VIVO SUPPLEMENTATION OF CREATINE AND RIBOSE PRESERVES HYPOXIC HEARTS FROM APOPTOSIS AND RIGHT VENTRICLE HYPERTROPHY.
No full textIt was previously found that H9c2 cardiomyocytes exposed to 24-h ischemia (1% O2 with glucose deprivation), were rescued by administration of 2.5 mM creatine + 5 mM D-ribose, while creatine or D-ribose alone were ineffective (1). These findings correlated with up-regulation of protein kinase B (Akt) phosphorylation. Creatine+D-ribose also blunted adenosine monophosphate-activated protein kinase (AMPK) and down-regulated apoptosis by reducing caspase-3 activation and poly (ADP-ribose) polymerase cleavage. In order to test the existence of an analogous mechanism in an in vivo context, five week-old mice were exposed to an atmosphere containing 10% O2 for 10 days, sacrificed and myocardial and pulmonary tissue harvested for structural and biochemical analyses. Mice were gavaged daily with vehicle, creatine, D-ribose or both.
Results showed that hypoxia induced marked right ventricle hypertrophy and left ventricle apoptosis. Both phenotypes were slightly reduced by the administration of either creatine or D-ribose, whereas the simultaneous administration almost completely reverted the effects of hypoxia. Furthermore, creatine+D-ribose contributed to blunt the increases in the activity of AMPK, Akt and JNK, but not of ERK, caused by hypoxia.
The increase in AMPK during hypoxia is an expected finding secondary to inadequate O2 supply with respect to needs. AMPK is probably upstream of Akt activation; in turn, Akt exerts pro-survival activities, however, by modulating the PI3-kinase pathway, Akt regulates cardiomyocyte size, thus inducing physiological cardiac hypertrophy (2). In addition, the development of right ventricle hypertrophy was found to be associated to left ventricle apoptosis (3), as reported here.
During hypoxia, pulmonary hypertension, causing pressure overload, contributes to right ventricle hypertrophy. We show here that the mRNA expression of endothelin-1, a short-lived peptide responsible for the pulmonary and heart disease (4), is increased by hypoxia. The administration of creatine+D-ribose led to reduction of the hypoxia-induced pulmonary overexpression of endothelin-1 mRNA.
Whereas creatine improves bioenergetics by recycling ADP into ATP via its shuttle property (5), ribose protects ischemic hearts by replenishing building blocks for ATP synthesis (6). By re-energization of not irreversibly-damaged myocardial cells. creatine+ribose appear to counteract myocardial injury by blunting the pathways originated from AMPK and Akt activation. This may constitute a useful therapeutic approach in several human diseases that involve systemic hypoxia, as for example chronic pulmonary obstructive diseases, heart failure as well as various forms of anemia.
References:
1- Caretti A et al, Cell Physiol Biochem.(2010), 26:831-838.
2- Rigor DL et al, Am J Physiol Heart Circ Physiol. (2009);296:H566-72.
3- Kitahori K et al, Circ Heart Fail. (2009);2:599-607.
4- Karmouty-Quintana H et al, FASEB J. (2012); 26:2546-2557.
5- Kammermeier H. J Mol Cell Cardiol. (1987);19:115-118.
6- Smolenski RT et al,. J Mol Cell Cardiol. (1998);30:673-683
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
La tutela delle lingue minoritarie nel diritto dell'Unione europea
No full textIl saggio esamina la tematica della protezione delle lingue minoritarie nel contesto dell'Unione europea. Il tema si collega, da un lato, alla ricchezza culturale e linguistica degli Stati membri e, dall'altro, alla tutela dei diritti fondamentali. Lo scritto muove dalla premessa che l'Unione Europea non gode di una competenza normativa diretta in tale settore, ma solo di una competenza "parallela", ai sensi del combinato disposto degli articoli 2, par. 5, TFUE e 6 TFUE. Tuttavia, l'Autrice ricava una rilevanza politico-costituzionale del tema nel quadro del diritto europeo. La collocazione lato sensu costituzionale del fenomeno produce conseguenze sia sul piano esterno dell'Unione (che si traduce nell'interesse dell'UE al rispetto dei diritti linguistici minoritari da parte degli Stati terzi candidati o potenziali candidati all'adesione), sia sul piano interno in relazione alle conseguenze del mancato rispetto dei diritti delle minoranze linguistiche da parte degli Stati membri
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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