1,720,973 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
Characterization of the Somatostatin cell population in the medial entorhinal cortex of the mouse
No full textThe medial entorhinal cortex receives converging input from the hippocampal formation, the parahippocampal region and multiple neocortical and subcortical regions. Since the discovery of spatially modulated cells, the medial entorhinal cortex is suggested to have a strong functional role in spatial navigation. In the process to illuminate the mysteries of the underlying spatial circuitry, a lot of attention has been directed toward the cell populations residing in the medial entorhinal cortex. Interneurons are indicated to have an important role in modulation of the local principal cells in cortical networks. However, in the medial entorhinal cortex, little is known about the different interneuron population.
The aim of this thesis was to describe the distribution and monosynaptic inputs to the somatostatin cell population of the medial entorhinal cortex, as well as optimizing the viral tracing protocol. To characterize the distribution of somatostatin cells, an adeno-associated virus helper virus was injected into the medial entorhinal cortex of somatostatin-Cre mice. To visualize monosynaptic tracing, somatostatin-Cre mice were injected with adeno-associated virus helper virus, followed by an incubation period and injection of EnvA G-deleted rabies virus. The brains were cut in the horizontal plane and cortical areas were delineated based on Nissl stains with Cresyl Violet. Adeno-associated virus helper virus and rabies virus fluorescent expression were immunohistochemically enhanced with AlexaFluor® dyes, and the viral expression was analyzed with confocal microscopy.
I tested multiple viral tracing protocols and the results showed that in order to receive optimal monosynaptic transport, the monosynaptic tracing method worked better in case of moderate to large injections with high titer virus. Immunohistochemical analyzes showed that the SST cell population was confined to deep layers of the MEC, whereas local monosynaptic labelled rabies cells were confined to and projected to superficial layers. Long-distance labelled cells were observed in the hippocampal formation, the parahippocampal region, the retrosplenial cortex and the medial septum. The results indicate that the somatostatin cells mainly receive inputs to starter cells in superficial layers. Long-distant monosynaptic transport show that the medial entorhinal cortex received stronger input from the parahippocampal region and the hippocampal formation than from neocortical and subcortical structures
Characterization of the Somatostatin cell population in the medial entorhinal cortex of the mouse
Full text linkThe medial entorhinal cortex receives converging input from the hippocampal formation, the parahippocampal region and multiple neocortical and subcortical regions. Since the discovery of spatially modulated cells, the medial entorhinal cortex is suggested to have a strong functional role in spatial navigation. In the process to illuminate the mysteries of the underlying spatial circuitry, a lot of attention has been directed toward the cell populations residing in the medial entorhinal cortex. Interneurons are indicated to have an important role in modulation of the local principal cells in cortical networks. However, in the medial entorhinal cortex, little is known about the different interneuron population.
The aim of this thesis was to describe the distribution and monosynaptic inputs to the somatostatin cell population of the medial entorhinal cortex, as well as optimizing the viral tracing protocol. To characterize the distribution of somatostatin cells, an adeno-associated virus helper virus was injected into the medial entorhinal cortex of somatostatin-Cre mice. To visualize monosynaptic tracing, somatostatin-Cre mice were injected with adeno-associated virus helper virus, followed by an incubation period and injection of EnvA G-deleted rabies virus. The brains were cut in the horizontal plane and cortical areas were delineated based on Nissl stains with Cresyl Violet. Adeno-associated virus helper virus and rabies virus fluorescent expression were immunohistochemically enhanced with AlexaFluor® dyes, and the viral expression was analyzed with confocal microscopy.
I tested multiple viral tracing protocols and the results showed that in order to receive optimal monosynaptic transport, the monosynaptic tracing method worked better in case of moderate to large injections with high titer virus. Immunohistochemical analyzes showed that the SST cell population was confined to deep layers of the MEC, whereas local monosynaptic labelled rabies cells were confined to and projected to superficial layers. Long-distance labelled cells were observed in the hippocampal formation, the parahippocampal region, the retrosplenial cortex and the medial septum. The results indicate that the somatostatin cells mainly receive inputs to starter cells in superficial layers. Long-distant monosynaptic transport show that the medial entorhinal cortex received stronger input from the parahippocampal region and the hippocampal formation than from neocortical and subcortical structures
A characterization of the somatostatin expressing cell population in the lateral entorhinal cortex of the mouse
No full textThe lateral entorhinal cortex is a part of the parahippocampal region, and has received attention for being involved in object and object characterization task, hence conveying nonspatial input to the hippocampal formation. In order to fully comprehend the functional role of the lateral entorhinal cortex, an important step is to understand the function of its local micro circuitry. Interneurons have been strongly implemented in the functioning of cortical networks. However, little is known concerning the interneurons in the lateral entorhinal cortex.
The aim of this thesis was to characterize the distribution of somatostatin cells in the lateral entorhinal cortex, and to look at their monosynaptic inputs. For the distribution analysis we injected an adeno-associated helper virus into the lateral entorhinal cortex of somatostatin- Cre mice. In our monosynaptic tracing experiments, we injected both adeno-associated helper virus and a G-deleted rabies virus into the lateral entorhinal cortex in our transgenic mouse line. We tested several viral strategies to optimize the viral tracing protocol. Cresyl Violet stained sections were used to delineate brain areas. Viral tracers were visualized either by the expression of fluorescent proteins or immunohistochemically enhanced with AlexaFluor dyes. The tissue was subsequently analyzed by using traditional microscopical techniques.
After testing several viral injections strategies, we found that the most optimal strategy involved separate injections of virus, separated by a sufficient incubation period which serves to ensure the framework for viral transport. The results from the monosynaptic viral tracing experiments showed that the somatostatin cells in the lateral entorhinal cortex have a strong intrinsic connectivity within the LEC, but also receive a substantial amount of input from extrinsic sources. Our distribution analysis showed that the majority of somatostatin cells are situated in deeper layers of the lateral entorhinal cortex, and that they are evenly distributed throughout the dorsoventral axis
A characterization of the somatostatin expressing cell population in the lateral entorhinal cortex of the mouse
Full text linkThe lateral entorhinal cortex is a part of the parahippocampal region, and has received attention for being involved in object and object characterization task, hence conveying nonspatial input to the hippocampal formation. In order to fully comprehend the functional role of the lateral entorhinal cortex, an important step is to understand the function of its local micro circuitry. Interneurons have been strongly implemented in the functioning of cortical networks. However, little is known concerning the interneurons in the lateral entorhinal cortex.
The aim of this thesis was to characterize the distribution of somatostatin cells in the lateral entorhinal cortex, and to look at their monosynaptic inputs. For the distribution analysis we injected an adeno-associated helper virus into the lateral entorhinal cortex of somatostatin- Cre mice. In our monosynaptic tracing experiments, we injected both adeno-associated helper virus and a G-deleted rabies virus into the lateral entorhinal cortex in our transgenic mouse line. We tested several viral strategies to optimize the viral tracing protocol. Cresyl Violet stained sections were used to delineate brain areas. Viral tracers were visualized either by the expression of fluorescent proteins or immunohistochemically enhanced with AlexaFluor dyes. The tissue was subsequently analyzed by using traditional microscopical techniques.
After testing several viral injections strategies, we found that the most optimal strategy involved separate injections of virus, separated by a sufficient incubation period which serves to ensure the framework for viral transport. The results from the monosynaptic viral tracing experiments showed that the somatostatin cells in the lateral entorhinal cortex have a strong intrinsic connectivity within the LEC, but also receive a substantial amount of input from extrinsic sources. Our distribution analysis showed that the majority of somatostatin cells are situated in deeper layers of the lateral entorhinal cortex, and that they are evenly distributed throughout the dorsoventral axis
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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