1,760,740 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
PVN-023-Ross-Field Notes-1992
Get PDFField notes describing excavations at Sites PVN 418, PVN 423, and PVN 262
Microinjection sites in PVN area.
No full text<p><b>Left panel, a representative photo of microinjection sites in the PVN evaluated by 50</b>. Arrows show the microinjection sites; Right panel, a schematic representation of microinjection sites. Blue dots or red open circles represent the sites of termination of the microinjections. Blue dots are considered to be within the PVN. Red open circles are considered to be outside of the PVN or at the margin of the PVN, which were excluded for data analysis. 3V, the third ventricle.</p
Variations on the Author
Get PDF“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
Get PDFWe 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
Hypothalamic PVN CRH Neurons Signal Through PVN GABA Neurons to Suppress GnRH Pulse Generator Frequency in Female Mice
Get PDFpeer reviewedCorticotropin-releasing hormone (CRH) neurons in the paraventricular nucleus of the hypothalamus (PVN) are central to the stress response. Chemogenetic activation of PVN CRH neurons decreases LH pulse frequency but the mechanism is unknown. In the present study, optogenetic stimulation of PVN CRH neurons suppressed LH pulse frequency in estradiol-replaced ovariectomized CRH-cre mice, and this effect was augmented or attenuated by intra-PVN GABAA or GABAB receptor antagonism, respectively. PVN CRH neurons signal to local GABA neurons, which may provide a possible indirect mechanism by which PVN CRH neurons suppress LH pulse frequency. Optogenetic stimulation of potential PVN GABAergic projection terminals in the hypothalamic arcuate nucleus in ovariectomized estradiol-replaced Vgat-cre-tdTomato mice via an optic fiber implanted in the arcuate nucleus suppressed LH pulse frequency. To further determine whether PVN CRH neurons signal through PVN GABA neurons to suppress LH pulsatility, we combined recombinase mice with intersectional vectors to selectively target these neurons. CRH-cre::Vgat-FlpO mice expressing the stimulatory opsin ChRmine in non-GABAergic CRH neurons alone or in combination with the inhibitory opsin NpHR3.3 in non-CRH-expressing GABA neurons in the PVN were used. Optogenetic stimulation of non-GABAergic CRH neurons suppressed pulsatile LH secretion; however, LH pulse frequency was not affected when CRH neurons were stimulated and PVN GABA neurons were simultaneously inhibited. Together, these studies demonstrate that suppression of LH pulse frequency in response to PVN CRH neuronal activation is mediated by GABAergic signalling intrinsic to the PVN and may incorporate PVN GABAergic projection to the hypothalamic GnRH pulse generator
TLR4 and GRP78 immunofluorescence in the PVN.
No full text<p>(A) Representative fluorescence microscopy illustrations showing GRP78 single-labeling in the PVN of four experimental groups. (B) Representative fluorescence microscopy illustrations showing TLR4 single-labeling in the PVN of saline or LPS treated rats. (C) Representative fluorescence microscopy illustrations showing TLR4 or GRP78 double-labeling in the PVN of LPS treated rats. Arrows indicate positive TLR4 and GRP78 cells. (D) Representative fluorescence microscopy illustrations showing GRP78 and NeuN double-labeling in the PVN. Arrows indicate positive GRP78 neurons; n = 3.</p
Gamma-aminobutyric acid (GABA) in the development of the paraventricular nucleus of the hypothalamus (PVN): implications for adult disease
Get PDF2012 Fall.Includes bibliographical references.The paraventricular nucleus of the hypothalamus (PVN) is the final common regulator of the neuroendocrine stress response. Humans with depression or anxiety disorders display altered regulation of this system and females are more likely to suffer from these disorders than males. This work investigated embryonic development of the PVN to identify cellular processes that might occur incorrectly (preferentially in females) and predispose the individual to altered regulation of stress responses. GABA acts as a neurotrophic factor during development. As the embryonic PVN is ringed by GABA (absence of GABA in the PVN) and a receptor for GABA is enriched in the PVN, it was hypothesized that this molecule would direct PVN development. Embryonic development was altered in mice either by genetic manipulation (receptor knockout mice) or by pharmacological blockade of the GABAA and GABAB receptors. Embryonic GABAA receptor antagonism caused a decrease in the number of neurons that expressed estrogen receptor α in and around the PVN. In female but not male mice lacking GABAB receptors, the cytoarchitecture of the PVN was altered. Specifically, estrogen receptor containing cells were misplaced and corticotropin releasing hormone was increased. Animals treated with a GABAB receptor antagonist during embryonic development copied the phenotype of receptor knockout mice. The in vivo effect of GABA signaling on cell placement was investigated in vitro with organotypic slice fluorescence video microscopy. Again only in females, blockade of the GABAB receptor caused neurons to increase migration speed. Thus GABA acts to restrict cells from moving outside of the PVN. When the GABAB receptor is antagonized, cells migrate outside of the PVN. To determine the consequence of an animal having altered PVN development, animals treated as embryos with the GABAB receptor antagonist were subjected to a battery of behavior tests as adults. Interestingly, females treated embryonically with CGP 55845 displayed an increased anxiety-like phenotype (female specific disorder) while males treated with the same compound displayed a hyperactivity-like phenotype (male specific disorder). Independent of sex, animals treated as embryos with the GABAB receptor antagonist displayed decreased depression-like behaviors and had a less robust stress response compared to vehicle treated animals. This work highlights the importance of GABA signaling in PVN development and the dependence of complex adult behaviors on embryonic brain organization as GABA receptor antagonism limited to a specific critical time period during embryonic development recreated cytoarchitectural and behavioral phenotypes of GABA receptor knockout mice
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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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