1,721,062 research outputs found
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
RECRUITMENT OF INHIBITORY MEK/ERK SIGNALING IN BRAIN REWARD CIRCUITRY FOLLOWING A HISTORY OF ETHANOL DEPENDENCE
No full textMitogen-activated and extracellular regulated kinase (MEK) and extracellular signal-regulated protein kinase (ERK) pathways may underlie ethanol-induced neuroplasticity. Here, the MEK inhibitor UO126 was used to probe the role of MEK/ERK signaling for the cellular response to an acute ethanol challenge in rats with or without a history of ethanol dependence. Ethanol (1.5 g/kg, i.p.) induced c-fos expression in brain regions associated both with rewarding and stressful ethanol actions. Under non-dependent conditions, alcohol-induced c-fos expression was generally not affected by MEK inhibition, with the exception of medial amygdala (MeA), and a similar pattern in the paraventricular nucleus (PVN). In contrast, following a history of dependence, a markedly suppressed c-fos response to acute ethanol was found in orbitofrontal cortex (OFC) and nucleus accumbens shell (AcbSh), key components of circuitry mediating positive drug reinforcement. The suppressed ethanol response in these regions was returned to normal by pre-treatment with UO126, demonstrating a recruitment of an ERK mediated inhibitory regulation in the post-dependent state. Conversely, in brain areas involved in stress responses (MeA, PVN), a MEK/ERK mediated cellular activation by acute ethanol was lost following a history of dependence. These data reveal highly region-specifi c neuroadaptations encompassing the MEK/ERK pathway in ethanol dependence. Recruitment of MEK/ERK mediated suppression of the ethanol response in OFC and AcbSh may refl ect devaluation of ethanol as a reinforcer, while loss of a MEK/ERK mediated response in MeA and PVN may reflect tolerance to its aversive actions. These two neuroadaptations could act in concert to facilitate progression into ethanol dependence
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
CRH SIGNALING AND THE DARK SIDE OF ADDICTION: LONG LASTING HYPERREACTIVITY TO STRESS IN ANIMALS WITH A HISTORY OF ALCOHOL DEPENDENCE
No full textIt is increasingly recognized that anti-reward systems are progressively recruited during the development of ethanol dependence, and may constitute a key component in maintaining the dependent phenotype. We recently demonstrated that
in rodents, repeated cycles of ethanol intoxication and withdrawal for a prolonged period of time induces a phenotype of long-lasting increased ethanol drinking that models several facets of human alcoholism. Here, we found that elevated stress sensitivity parallels the high ethanol preference in this model, and contributes to the propensity to consume increased amounts of ethanol. After 7 weeks of daily cycles of intoxication and withdrawal rats were allowed to recover for 3 weeks without access to ethanol. In the first experiment we subjected rats to a punished drinking test (Vogel) w/o antagonist pretreatment with a corticotropin releasing hormone receptor 1 (CRH1R). Dependent rats showed a more pronounced behavioral suppression during the punished drinking period than controls. This suppression was alleviated by the CRH1R antagonist.exposed rats and controls were subjected to a 2-bottle freechoice, continuous access drinking paradigm. We then tested the effect of theantagonist on drinking behavior in a 2-bottle free choice, 1 hr-limited accessparadigm. No effect of the drug on ethanol consumption was found. In a second setof rats we asked whether the increased sensitivity to stress affects home cage drinking. As expected, previously exposed rats consumemarkedly higher amounts ofethanol than controls. Rats were than subjected for 3 consecutive days to sessions ofinescapable stress (forced swimming in cold water). During the week after thestressor rats with a history of dependence showed a sustained increase in drinkingfrom their previous base line, while control rats did not. A third group of animals wasanalyzed for CRH1R receptor expression and density. In conclusion, we provideevidence for an overactive CRH system in rats with a history of dependence causing hyper-emotionality and thereby contributing to relapse behavior
SIGNAL TRANSDUCTION IN ALCOHOL-PREFERRING AA AND ALCOHOL-AVOIDING ANA RAT LINES
No full textAA and ANA rats are one of the earliest and well established rodent models for ethanol preference. Several candidate genes have been suggested to confer genetic susceptibility for alcoholism in these lines including mitogen-activated protein kinases, Akt/PKB and GSK-3 pathways. The aim of the study was to compare the protein levels and phopshorylation of ERK 1/2, Akt and GSK-3 in AA and ANA rats under basal condition and after acute ethanol challenge. Animals were injected with either ethanol (1.5 g/kg) or saline and killed 20 or 45 minutes after injection. Brains were frozen and dissected, nucleus accumbens (NAcc) and cingulate cortex (CCx) were extracted and subject to immunobloting with total and phosphospecifi c antibodies. Baseline differences in ERK 1/2 phopshorylation were discovered between AA and ANA lines. Intraperitoneal injection of ethanol (1.5 g/kg) induced a rapid and transient decrease in ERK 1/2 phosphorylation in both CCx and NAcc within 20 minutes which was already reverting towards control levels at the 45 minute time point. There was no change in the total ERK levels. Phosphorylation of both GSK-3 and Akt in CCx of AA rats was increased 45 minutes after ethanol injection, however no changes were found in NAcc. In ANA rats there were no statistically signifi cant changes in all structures. Thus, AA rats are more susceptible to acute effects of ethanol involving some of the mitogen-activated protein kinases, Akt/PKB and GSK-3 pathways, and these differences are more prominent in the CCx compared to the NAcc
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