1,721,042 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
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
Ein aufschlussreiches Trio: Stress, Imagination und der Gyrus Angularis formen die Gedächtnisintegration
No full textUpdating memory is essential for maintaining an accurate model of the world. Yet, our understanding of how we integrate new information into existing memory has remained limited. Therefore, this work aims to delineate the factors that shape mnemonic integration. Building upon prior research emphasizing the anterior hippocampus's role in mnemonic integration and the impact of stress on hippocampal function, Study 1 leveraged fMRI to explore how acute stress affects mnemonic integration. Although stress boosted recognition, it disrupted a representational change in the anterior hippocampus, likely by decreasing hippocampal activity during insight. Inspired by the anterior hippocampus’s role in mnemonic integration and imagination, Study 2 utilized fMRI to investigate the behavioral and neural consequences of imagination-based insight. While improving overall memory, imagination resulted in lower immediate insight and abolished a representational change in the anterior hippocampus, possibly due to heightened hippocampal activity during imagination. To explore the role of the angular gyrus in mnemonic integration, given its implications in memory and imagination, we combined inhibitory continuous theta burst stimulation (cTBS) at the angular gyrus with electroencephalography (EEG) in Study 3. Angular gyrus inhibition reduced the memory boost for integrated narratives and eliminated representational changes for linked events in the theta band. These findings converge in a comprehensive model, positing the angular gyrus as a buffer and proposing an inverted U-shaped relationship between hippocampal activity and mnemonic reconfiguration when integrating previously separate events. Altogether, these insights enhance our comprehension of mnemonic integration and may aid in developing a better understanding of the etiology of conditions such as posttraumatic stress disorder (PTSD)
On the Trail of Memory Traces: How Stress Affects Initial Memory Formation and Updating Processes
No full textForming and updating memories are central aspects of human cognition, which are strongly affected by stressful encounters. Due to the large variety in study designs and lack of neural correlates, our understanding of how stress affects encoding and post-retrieval memory processes is limited. To uncover the underlying mechanisms, three multi-day neuroimaging studies were conducted as part of this thesis. Using Magnetoencephalography (MEG), study I investigated the role of theta oscillations in emotional encoding under stress. Studies II and III aimed to further delineate the interaction between stress and memory updating processes by employing functional Magnetic Resonance Imaging (fMRI) in a three-day associative memory task. While studies I and II employed a behavioral stress induction, study III leveraged a pharmacological intervention to increase either noradrenergic activity or cortisol levels. Despite differing methodologies, results of all three studies consistently highlight the critical role of the hippocampus and connected occipito parietal areas in memory formation and updating under stress. While study I revealed that increased theta oscillations in this cortico-hippocampal network during the encoding of emotionally negative images were linked to memory enhancements, results from studies II and III showed that stress, and especially noradrenaline, following a strong activation of a similar network during reactivation, significantly impaired subsequent memory. These findings suggest the cortico-hippocampal network to reflect a critical yet vulnerable target to stress across the whole memory formation process, yielding major relevance for (i) understanding the pathogenesis of stress-related disorders and (ii) developing targeted interventions to alleviate symptoms emerging from maladaptive memories
Declarative memory modulation in threatening environments: Introducing a cognitive account based on aversive prediction errors
No full textDeclarative memory aids behavioral adaptation by identifying predictors of important consequences. To ensure an efficient retrieval of such self-relevant information considering the overabundance of everyday impressions, long-lasting memory is formed relatively sparsely. The present work aimed to characterize principles under which this memory modulation operates in threatening environments. Prior studies have repeatedly shown an unspecific modulation of memory for stimuli surrounding salient experiences, but more recent evidence additionally points towards a more specific enhancement of memory that only affects items belonging to a motivationally significant category. In Study 1, we successfully replicated a category-specific `online' memory enhancement, which was characterized by the superior memory for stimuli from a shock-associated category that were encoded during fear conditioning. This effect prospectively carried over to stimuli from the same category that were subsequently encoded without the threat of shock. However, our results cast doubt over claims that this category-specific memory modulation also retroactively affects stimuli from the shock-associated category that were encoded prior to fear conditioning. In Study 2, we proposed an even more specific modulation of memory that operates at the level of unique stimuli. In line with established models, we found that greater physiological arousal elicited by individual trial outcomes was linked with better subsequent memory performance. Critically, we present evidence for a novel cognitive account of memory modulation that goes beyond these influences of physiological arousal and is characterized by an improved memory for stimuli associated with surprising outcomes, which were formalized as aversive prediction errors (PEs). In Study 3, we aimed to characterize the neural basis of this PE-driven account using fMRI. Results suggested a mechanism that is distinct from expectancy-congruent modes of memory formation associated with an activation of medial-temporal structures and instead relies on the recruitment of the salience network. Overall, our results paint a nuanced picture of an adaptive memory system that uses multiple complementary strategies to ensure an efficient storage of self-relevant information
- …
