1,721,076 research outputs found
Modularity-based graph partitioning using conditional expected models
No full textModularity-based partitioning methods divide networks into modules by comparing their structure against random networks conditioned to have the same number of nodes, edges, and degree distribution. We propose a novel way to measure modularity and divide graphs, based on conditional probabilities of the edge strength of random networks. We provide closed-form solutions for the expected strength of an edge when it is conditioned on the degrees of the two neighboring nodes, or alternatively on the degrees of all nodes comprising the network. We analytically compute the expected network under the assumptions of Gaussian and Bernoulli distributions. When the Gaussian distribution assumption is violated, we prove that our expression is the best linear unbiased estimator. Finally, we investigate the performance of our conditional expected model in partitioning simulated and real-world networks.National Institutes of Health (U.S.) (Grant 5R01EB000473)National Institutes of Health (U.S.) (Grant P41 RR013642)National Institutes of Health (U.S.) (Grant R01 EB002010
Brainstorm: A User-Friendly Application for MEG/EEG Analysis
Get PDFBrainstorm is a collaborative open-source application dedicated to magnetoencephalography (MEG) and electroencephalography (EEG) data visualization and processing, with an emphasis on cortical source estimation techniques and their integration with anatomical magnetic resonance imaging (MRI) data. The primary objective of the software is to connect MEG/EEG neuroscience investigators with both the best-established and cutting-edge methods through a simple and intuitive graphical user interface (GUI).National Institutes of Health (U.S.) (R01-EB002010)National Institutes of Health (U.S.) (R01-EB009048)National Institutes of Health (U.S.) (R01-EB000473)Institut national de physique nucléaire et de physique des particulesFrance. Agence nationale de la rechercheCleveland Clinic Neurological Institut
Using Brain Waves to Control Computers and Machines
No full textHumans have traditionally interacted with computers or machines by using their hands to manipulate computer components. This kind of human-computer interaction (HCI), however, considerably limits the human’s freedom to communicate with machines. Over the years, many attempts have been made to develop technologies that include other modalities used for communication, for example, speech or gestures, to make HCI more intuitive. Recent advances in cognitive neuroscience and neuroimaging technologies in particular have allowed for the establishment of direct communication between the human brain and machines. This ability is made possible through invasive and noninvasive sensors that can monitor physiological processes reflected in brain waves, which are translated online into control signals for external devices or machines
Alternative Fast and Slow Primary Charge‐Separation Pathways in Photosystem II
No full textPhotosystem-II (PSII) is a multi-subunit protein complex that harvests sunlight to perform oxygenic photosynthesis. Initial light-activated charge separation takes place at a reaction centre consisting of four chlorophylls and two pheophytins. Understanding the processes following light excitation remains elusive due to spectral congestion, the ultrafast nature, and multi-component behaviour of the charge-separation process. Here, using advanced computational multiscale approaches which take into account the large-scale configurational flexibility of the system, we identify two possible primary pathways to radical-pair formation that differ by three orders of magnitude in their kinetics. The fast (short-range) pathway is dominant, but the existence of an alternative slow (long-range) charge-separation pathway hints at the evolution of redundancy that may serve other purposes, adaptive or protective, related to formation of the unique oxidative species that drives water oxidation in PSII
Repetitive transcranial magnetic stimulation of the dorsolateral prefrontal cortex enhances working memory
Get PDFNeuroimaging and electrophysiological studies have unequivocally identified the dorsolateral prefrontal cortex (DLPFC) as a crucial structure for top-down control of working memory (WM) processes. By modulating the excitability of neurons in a targeted cortical area, transcranial magnetic stimulation (TMS) offers a unique way to modulate DLPFC function, opening the possibility of WM facilitation. Even though TMS neuromodulation effects over the left DLPFC have successfully improved WM performance in patients with depression and schizophrenia in a multitude of studies, raising the potential of TMS as a safe efficacious treatment for WM deficits, TMS interventions in healthy individuals have produced mixed and inconclusive results. Here, we stimulated the left DLPFC of healthy individuals using a high-frequency repetitive TMS protocol and evaluated behavioral performance in a battery of cognitive tasks. We found that TMS treatment enhanced WM performance in a verbal digit span and a visuospatial 2-back task
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
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
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