1,720,992 research outputs found
Muscle Oximetry in Sports Science: A Systematic Review
No full textSince the introduction (in 2006) of commercially available portable wireless muscle oximeters, the use of muscle near-infrared spectroscopy (NIRS) technology is gaining in popularity as an application to observe changes in muscle metabolism and muscle oxygenation during and after exercise or training interventions in both laboratory and applied sports settings
Functional near-infrared spectroscopy to probe sensorimotor region activation during electrical stimulation-evoked movement
No full textThis study used non-invasive functional near-infrared spectroscopy (fNIRS) neuroimaging to monitor bilateral sensorimotor region activation during unilateral voluntary (VOL) and neuromuscular electrical stimulation (NMES)-evoked movements
Effects of increasing neuromuscular electrical stimulation current intensity on cortical sensorimotor network activation: A time domain fNIRS study
Full text linkNeuroimaging studies have shown neuromuscular electrical stimulation (NMES)-evoked movements activate regions of the cortical sensorimotor network, including the primary sensorimotor cortex (SMC), premotor cortex (PMC), supplementary motor area (SMA), and secondary somatosensory area (S2), as well as regions of the prefrontal cortex (PFC) known to be involved in pain processing. The aim of this study, on nine healthy subjects, was to compare the cortical network activation profile and pain ratings during NMES of the right forearm wrist extensor muscles at increasing current intensities up to and slightly over the individual maximal tolerated intensity (MTI), and with reference to voluntary (VOL) wrist extension movements. By exploiting the capability of the multi-channel time domain functional near-infrared spectroscopy technique to relate depth information to the photon time-of-flight, the cortical and superficial oxygenated (O2Hb) and deoxygenated (HHb) hemoglobin concentrations were estimated. The O2Hb and HHb maps obtained using the General Linear Model (NIRS-SPM) analysis method, showed that the VOL and NMES-evoked movements significantly increased activation (i.e., increase in O2Hb and corresponding decrease in HHb) in the cortical layer of the contralateral sensorimotor network (SMC, PMC/SMA, and S2). However, the level and area of contralateral sensorimotor network (including PFC) activation was significantly greater for NMES than VOL. Furthermore, there was greater bilateral sensorimotor network activation with the high NMES current intensities which corresponded with increased pain ratings. In conclusion, our findings suggest that greater bilateral sensorimotor network activation profile with high NMES current intensities could be in part attributable to increased attentional/pain processing and to increased bilateral sensorimotor integration in these cortical regions
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
Neuromuscular electrical stimulation and voluntary wrist extension movements elicit similar sensorimotor cortex activation: A continuous-wave fNIRS study
No full textOur previous study [1] using a high-cost time-domain (<i>TD</i>) functional near-infrared spectroscopy (<i>fNIRS</i>) prototype instrument showed that unilateral <i>neuromuscular electrical stimulation (NMES)</i> evoked wrist extension movements (50% of maximal tolerated current intensity-50%MTI) activated (increase in oxy-hemoglobin-O<sub>2</sub>Hb and concomitant decrease in deoxy-hemoglobin-HHb) a similar region of the contralateral <i>sensorimotor cortex (SMC)</i> as that of voluntary (<i>VOL</i>) movements. The aim of this study was to use a <i>continuous-wave (CW)</i> relatively low-cost commercial <i>fNIRS</i> instrument to measure contralateral (left) and ipsilateral (right) SMC activation (O<sub>2</sub>Hb and HHb time course, integral [O<sub>2</sub>Hb<sub>INT</sub> and HHb<sub>INT</sub>] and peak levels [O<sub>2</sub>Hb<sub>max</sub> and HHb<sub>min</sub>]) during <i>NMES</i> (50%MTI) and <i>VOL</i> wrist extension movements of the right arm in 7 healthy male volunteers. Both <i>NMES</i> and <i>VOL</i> wrist extension movements activated the contralateral (left) and ipsilateral (right) SMC, however, the level of contralateral SMC activation was significantly greater than the ipsilateral SMC. Although the HHb parameters (HHb<sub>INT</sub>, HHb<sub>min</sub>) indicated that there was no significant difference between conditions, the O<sub>2</sub>Hb parameters (O<sub>2</sub>Hb<sub>INT</sub> and O<sub>2</sub>Hb<sub>max</sub>) indicated a significantly greater contralateral SMC activation during <i>VOL</i> than <i>NMES</i>. Since HHb is less influenced by skin blood flow changes than O<sub>2</sub>Hb, we consider that HHb parameters provide a more accurate estimation of task-related cortical activation. In conclusion, these <i>CW-fNIRS</i> findings using HHb parameters indicate that <i>NMES</i> at moderate current intensity (50%MTI) and <i>VOL</i> wrist extension movements elicit a similar contralateral SMC activation, which confirms our previous study using a <i>TD-fNIRS</i> instrument
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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