1,720,961 research outputs found
Breathing is coupled with voluntary action and the cortical readiness potential
Full text linkVoluntary action is a fundamental element of self-consciousness. The readiness potential (RP), a slow drift of neural activity preceding self-initiated movement, has been suggested to reflect neural processes underlying the preparation of voluntary action; yet more than fifty years after its introduction, interpretation of the RP remains controversial. Based on previous research showing that internal bodily signals affect sensory processing and ongoing neural activity, we here investigated the potential role of interoceptive signals in voluntary action and the RP. We report that (1) participants initiate voluntary actions more frequently during expiration, (2) this respiration-action coupling is absent during externally triggered actions, and (3) the RP amplitude is modulated depending on the respiratory phase. Our findings demonstrate that voluntary action is coupled with the respiratory system and further suggest that the RP is associated with fluctuations of ongoing neural activity that are driven by the involuntary and cyclic motor act of breathing.LNCOCN
Time-of-day effect on adaptive immune responses and central nervous system autoimmunity
No full textCircadian rhythms are present in virtually all organisms and are evolutionarily conserved time-keeping mechanisms describing biological processes that oscillate in approximately 24-hour patterns. These rhythms are kept in synchrony by environmental cues and participate in the proper function of several physiological processes, among which are the innate and the adaptive immune system. Circadian rhythms are beneficial as they allow organisms to anticipate recurring events and to tune their behavioral response accordingly. With respect to immunity, these rhythms help the host to modulate its reactivity to times at which the probability of pathogen encounters may be highest. In addition, time-of-day-dependent activation of the immune system must be tightly controlled to trigger an efficient immune response without inducing side effects such as autoimmunity.
It is now widely accepted that time-of-day-dependent mechanisms can govern an acute immune response. However, we still do not understand why adaptive immune responses remain oscillatory over long periods of time. In the first part of this thesis, I demonstrate that the initial time of the challenge is key to shape the adaptive immune response for the ensuing several weeks. In particular, the time-of-day-dependent migration of dendritic cells generates oscillations in lymph node cellularity, which persists for weeks after the initial challenge and results in an increased likelihood of functional encounters between antigen-presenting dendritic cells and antigen-recognizing T cells. This is especially important in the context of immune responses to vaccination. Additionally, I show that rhythmic migration, activation, and function of different immune cells are required to create and maintain an efficient immune response over time.
However, immune responses are not always beneficial as is the case for an immune response directed against self, which can lead to autoimmunity. The second part of the thesis aims to decipher to what extent circadian rhythms are contributing to the development of experimental autoimmune encephalomyelitis (EAE), the most common mouse model of multiple sclerosis (MS). Using this model, I show a time-of-day dependent infiltration of immune cells into the central nervous system (CNS) during EAE development that is independent of disease severity. Interestingly, I observe a substantial increase in blood circulating CD11b+Ly6G+ cells before the appearance of symptoms associated with a switch in their phenotype. Altogether, these data suggest a potential contribution of CD11b+Ly6G+ leukocytes to early disease. Analysis of the mRNA levels in the spinal cord of EAE animals reveal a time-of-day dependent expression of both Cxcl1 and Cxcl2 chemokines responsible for the migration of monocytes and neutrophils, respectively. This study suggests the importance of circadian oscillations in cell infiltration in the central nervous system, as well as the importance of CD11b+Ly6G+ leukocytes in EAE development and identifies these cells as potential early biomarkers for diagnosis purposes and new therapeutic targets in MS patients.</p
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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