1,720,972 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
Self-organization and statistics of dislocations during monotonic and plastic deformation
No full textThe aim of this doctoral thesis, is the examination of self-organization and statistical behavior of dislocations during monotonic and cyclic deformation. The examination proceeds in the framework of gradient theory, probability theory and stochastic processes. Initially a new formalism for the application of standard properties of random functions leading to gradient constitutive equations is developed. What follows is the application of stochastic processes for the evolution of dislocation densities during monotonic and cyclic deformation. Finally, a complementary gradient-stochastic model for the cyclic deformation and the nucleation of persistent slip bands is developed where well-known experimental results reproduced in a good agreement.Ο στόχος της παρούσης διδακτορικής διατριβής είναι η μελέτη της αυτοοργάνωσης και στατιστικής συμπεριφοράς των εξαρμόσεων κατά τη μονότονη και κυκλική παραμόρφωση. Η μελέτη γίνεται στα πλαίσια της θεωρίας βαθμίδων, της θεωρίας των πιθανοτήτων και των στοχαστικών διεργασιών. Αρχικά αναπτύσσεται ένας νέος φορμαλισμός για την εφαρμογή των ιδιοτήτων συναρτήσεων τυχαίων μεταβλητών στην εξαγωγή βαθμιδικών καταστατικών εξισώσεων για την παραμόρφωση των υλικών τόσο στη μακροκλίμακα όσο και στη μεσοκλίμακα. Στη συνέχεια γίνεται εφαρμογή της θεωρίας των στοχαστικών διεργασιών για την εξέλιξη της πυκνότητας των εξαρμόσεων κατά τη μονότονη και κυκλική παραμόρφωση. Τέλος αναπτύσσεται ένα συζευγμένο στοχαστικό-βαθμιδικό μοντέλο για την κυκλική παραμόρφωση και την πυρηνοποίηση των - παραμένουσας ολίσθησης, όπου αναπαράγονται με συνεπή τρόπο γνωστά πειραματικά δεδομένα
Higher-Order Adaptive Dynamical System Modelling of the Role of Epigenetics in Major Depressive Disorder
Full text linkThis paper focuses on the modelling of an experiment concerning the emotional response as a result of thinking about happy memories for non-depressed and depressed individuals. Furthermore, it shows the role of epigenetic changes in this experiment by showing that the depletion of the brain-derived neurotrophic factor (BDNF) gene expression, often associated in literature both with depression and memory functions, can lead to a depressed individual and a change of feeling state with happy memory recall. An adaptive dynamical system model was designed for this process, which involves higher-order adaptation in emotion regulation. This computational model was represented as a higher-order adaptive network model and showcases an individual who, at first, does not have a major depressive disorder (MDD), but then a stressful life event happens, leading to epigenetic changes associated with BDNF depletion that make the person develop depression.</p
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
A Second-Order Adaptive Network Model for Political Opinion Dynamics
Full text linkThis paper introduces a second-order adaptive network model for simulating political opinion dynamics, considering cognitive, affective, and social factors. The model, grounded in political psychology and communication theories, illustrates how individuals’ opinions evolve in response to external stimuli such as political parties and media. It also explores the impact of individuals’ reasoning abilities and initial viewpoints on their rationality and cognitive flexibility. Through simulation experiments, the paper demonstrates the model’s capacity to generate realistic outcomes such as homophily and polarization phenomena. It further discusses the model’s implications for mitigating misinformation spread and reducing polarization in political opinion dynamics, identifying key influencing factors and potential interventions. The paper contributes to computational politics by offering an innovative approach to modeling individual and collective opinion formation processes, acknowledging the complexity and adaptivity of cognitive, affective, and social dynamics.</p
The Role of Epigenetics in OCD:A Multi-order Adaptive Network Model for DNA-Methylation Pathways and the Development of OCD
Full text linkObsessive-Compulsive Disorder (OCD) can be classified as a psychiatric condition which is characterised by persistent intrusive thoughts, to be called obsessions, and repetitive behaviours and mental acts, to be called compulsions. Recent studies have linked OCD to increased methylation of the oxytocin receptor (OXTR) gene which potentially impacts OCD-linked social and emotional behaviours. Options to treat OCD include cognitive-behavioural therapy (CBT) and selective serotonin reuptake inhibitors (SSRI). Challenges to these treatment options exist due to some individuals not responding well to SSRIs. The paper introduces a hypothetical treatment option to restore OXTR functionality. The research focuses on epigenetics in OCD and presents simulations involving DNA methylation changes. In the first presented scenario OCD development is shown triggered by childhood trauma. Scenario two introduces an epigenetic therapy to counteract the OCD symptoms by demethylating the OXTR gene. The simulated hypothetical therapy shows the potential to relieve OCD symptoms. Epigenetic drugs used in diseases like cancer, do indeed suggest potential for usage in other disorders like OCD.</p
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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