1,721,119 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
The functional connectivity of the right superior temporal gyrus is associated with psychological risk and resilience factors for suicidality
Full text linkIntroduction: Suicide attempters show increased activation in the right superior temporal gyrus (rSTG). Here, we investigated the rSTG functional connectivity (FC) to identify a functional network involved in suicidality and its associations with psychological suicidality risk and resilience factors. Methods: The resting state functional magnetic resonance imaging data of 151 healthy individuals from the Human Connectome Project Young Adult database were used to explore the FC of the rSTG with itself and with the rest of the brain. The correlation between the rSTG FC and loneliness and purpose in life scores was assessed with the NIH Toolbox. The effect of sex was also investigated. Results: The rSTG had a positive FC with bilateral cortical and subcortical regions, including frontal, temporal, parietal, occipital, limbic, and cerebellar regions, and a negative FC with the medulla oblongata. The FC of the rSTG with itself and with the left central operculum were associated with loneliness scores. The within rSTG FC was also negatively correlated with purpose in life scores, although at a trend level. We did not find any effect of sex on FC and its associations with psychological factors. Limitations: The cross-sectional design, the limited age range, and the lack of measures of suicidality limit the generalizability of our findings. Conclusions: The rSTG functional network is associated with loneliness and purpose in life. Together with the existing literature on suicide, this supports the idea that the neural activity of rSTG may contribute to suicidality by modulating risk and resilience factors associated with suicidality
Whole-brain functional neuroimaging correlates of cognitive flexibility impairments in people with mental disorders: A transdiagnostic coordinate-based meta-analysis
Full text linkIntroduction: Set-shifting skills allow individuals to flexibly adapt their behavior against environmental feedback. Impairments of this cognitive control process represent the core features of heterogeneous mental disorders. However, it is unclear whether the neural mechanisms of set-shifting impairments are shared across different mental disorders. Materials and methods: We systematically screened the neuroimaging literature and conducted a coordinate-based meta-analysis. Of 1930 publications, 22 functional neuroimaging studies investigating neural response differences during the performance of set-shifting paradigm on the scanner in individuals with a mental disorder, including schizophrenia, depression, anxiety disorder, neurodevelopmental disorders, eating disorders, obsessive-compulsive disorder, behavioral addiction were selected. Results: We found significant hyperactivation responses during set-shifting in the right medial frontal/anterior cingulate gyrus, the right superior parietal lobule, and the left superior temporal gyrus in patients with schizophrenia, autism spectrum disorders, or generalized anxiety disorder. Conclusions: Our findings suggest a common substrate of increased activity in the frontoparietal network (FPN) across mental disorders during set-shifting. FPN activation responses may represent a biomarker of altered cognition across traditional nosographic categories
Searching for relief: Drosophila melanogaster navigation in a virtual bitter maze
Full text linkAnimals use relief-based place learning to pinpoint a specific location where noxious stimuli are diminished or abolished. Here we show how the optogenetically-induced activation of bitter-sensing neurons in Drosophila melanogaster elicits pain-like behavioural responses and stimulates the search for a place where this activation is relieved. Under this “virtual” stimulation paradigm it would be feasible to test relief learning several times throughout an animal's lifespan, without the potentially damaging effects which may result from the repeated administration of “real” heat or electrical shock. Furthermore, virtual bitter taste could be used in place of virtual pain stimulation to guide conditioned place preference and study learning processes. We also propose that spatially-specific reduction of locomotor velocity may provide immediate evidence of relief-based place learning and spatial memory
Late-life suicide: machine learning predictors from a large European longitudinal cohort
Full text linkBackground: People in late adulthood die by suicide at the highest rate worldwide. However, there are still no tools to help predict the risk of death from suicide in old age. Here, we leveraged the Survey of Health, Ageing, and Retirement in Europe (SHARE) prospective dataset to train and test a machine learning model to identify predictors for suicide in late life. Methods: Of more than 16,000 deaths recorded, 74 were suicides. We matched 73 individuals who died by suicide with people who died by accident, according to sex (28.8% female in the total sample), age at death (67 ± 16.4 years), suicidal ideation (measured with the EURO-D scale), and the number of chronic illnesses. A random forest algorithm was trained on demographic data, physical health, depression, and cognitive functioning to extract essential variables for predicting death from suicide and then tested on the test set. Results: The random forest algorithm had an accuracy of 79% (95% CI 0.60-0.92, p = 0.002), a sensitivity of.80, and a specificity of.78. Among the variables contributing to the model performance, the three most important factors were how long the participant was ill before death, the frequency of contact with the next of kin and the number of offspring still alive. Conclusions: Prospective clinical and social information can predict death from suicide with good accuracy in late adulthood. Most of the variables that surfaced as risk factors can be attributed to the construct of social connectedness, which has been shown to play a decisive role in suicide in late life
Towards a unified vision on animal navigation
No full textThe study of animal navigation is a complex and fertile field of research: Several questions regarding how animals relate to external stimuli, integrating them to perform their everyday movement routine, have been or are being addressed in different organisms and taxa, both from the behavioural and the neuronal activity point of view. Several invertebrate model organisms are the object of studies aimed at unravelling how they navigate and their ability to precisely return to a starting point and also how navigational information is communicated to conspecifics when precise social structures are present. Also, vertebrates are studied because of the interest in their orientation abilities while migrating, homing over impressive distances and studying exploration, orientation and space recognition. Last, research on the navigation capabilities of humans pursues a better understanding of the neural architecture involved in these processes in the remarkable effort to find answers and possible solutions to impairments, lesions and diseases. However, an ‘all-inclusive’ vision of navigation still appears to be in its embryonic state: A better perspective could (and should) shift from a paradigm where single research teams are centred on studying navigation in a single genus or species towards a more comprehensive evolutionary-centred view, searching systematically for behavioural analogies, and possibly for homologies in neural architecture between different taxa. In this review, we introduce examples of relevant topics in animal navigation from distinct animal groups, highlighting the similar approaches of those studies, and why, in our opinion, this research field could profit from a ‘new’ perspective
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
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