1,721,012 research outputs found
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
The relative contributions of different sensory afferent and corticocortical projections on the motor cortex during skilled motor behaviour
No full textThe motor system is required to perform an endless number of movements. To do this, general motor plans are created for similar groups of movements that can be adjusted for specific iterations of each movement. To ensure that the motor plan is accurate to the specific iteration of the movement, sensory information from a variety of modalities is integrated into the plan via corticocortical connections to the motor cortex. Shorter sensorimotor loops will also project to various cortical areas involved in generating the motor plan to modulate this process with updated sensory afference. However, it is still unclear exactly how these circuits interact with each other during the planning and execution of skilled motor behaviour. The current study used two transcranial magnetic stimulation paradigms to investigate these interactions. Short-interval intracortical inhibition (SICI) probes the longer corticocortical loops, while short-latency afferent inhibition (SAI) probes the shorter sensory afferent circuits. Performing both techniques during a waveform tracking task involving a planning phase and movement execution phase, the current study could investigate interactions between corticocortical and sensory afferent projections during skilled motor behaviour.
Twenty-three healthy individuals completed two sessions where SICI and SAI were quantified in the first dorsal interosseous muscle during a waveform tracking task. SICI was assessed using an unbalanced transcranial magnetic stimulus that induced a posterior-anterior current in the underlying tissue with a positive phase lasting 70 µs (PA70). SAI was assessed using a stimulus that induced a posterior-anterior current in the underlying tissue with a positive phase lasting 120 µs (PA120) or a stimulus that induced an anterior-posterior current in the underlying tissue with a positive phase lasting 30 µs (AP30). TMS stimuli were delivered at seven different time points during the task: one baseline time point where the waveform was hidden from participants, two planning time points (-0.5s and -0.25s from movement onset), a time point at the onset of the movement, and three time points during the movement (1s, 2s, 3s after movement onset). Results showed that the effect of the conditioning stimulus was stronger for SICI than SAI across each of the time points during the task. We also found that the magnitude of difference in the weighting of SICI and SAI changed across the time point.
These findings suggest that a variety of sensorimotor loops converge on the corticospinal neuron in the primary motor cortex to shape motor output. The corticocortical connections probed by SICI play a dominant role consistent with setting the initial motor plan. In contrast, the sensory afferent projections probed by SAI play a modulatory role updating the initial plan to reflect current sensory states and providing feedback. The interactions between corticocortical and sensory afferent circuits are important for healthy motor control and explain how the motor system is able to perform a seemingly endless number of movements
The Contribution of Oscillatory Activity to the Modulation of Different Sensorimotor Circuits Under Varying Working Memory Load
Get PDFGoal-directed movement requires a series of highly coordinated voluntary motor outputs, which need to adequately integrate information from the body’s internal and external environments to be executed successfully. The integration of sensory information to inform motor output is known as sensorimotor integration. Sensorimotor integration involves afferent projections to the primary motor cortex (M1) via multiple sensorimotor loops. These sensorimotor loops eventually converge on the corticospinal neuron (CSN) to determine motor out. However, the specific groups or circuits of interneurons targeted by the different sensorimotor loops are not known. The current study combined controllable pulse parameter transcranial magnetic stimulation (cTMS) with electroencephalography (EEG) to assess the association between oscillatory brain activity in different brain regions and sensorimotor integration in the M1 measured by short-latency afferent inhibition (SAI). To facilitate the quantification of any association, both oscillatory brain activity and SAI were measured during a working memory task under varying working memory demands. SAI circuits were probed using three different cTMS configurations, posterior-anterior (PA) current with a 120 μs duration (PA120), anterior-posterior (AP) current with a 120 μs duration (AP120) and AP current with a 30 μs duration (AP30). Increased working memory load reduced SAI across all three current configurations. However, the magnitude of the reduction decreased from PA120 to AP120 to AP30. SAI-EEG associations revealed that the effect of working memory load on SAI was modulated by the amount of parietal alpha and frontocentral low beta activity. The current results suggest several sensorimotor circuits converge on the CSN, all receiving similar projections from various brain regions under working memory load. It seems that distinctions across the circuits are dependent on other unique modulatory projections, which are not probed by working memory load
The Effect of Working Memory on Corticospinal Excitability
Get PDFSkilled behavior is dependent upon the ability to extract and integrate sensory afference into appropriate output from motor cortex. This process is dynamic with executive control, guided by declarative knowledge (i.e. facts and semantics) and able to shape subconscious processes guided by procedural knowledge. Previous work by Suzuki et al.1 used short-latency afferent inhibition to show that verbal working memory demands (a declarative construct) change afferent projections to the cortical motor output neurons, providing a route by which executive control shapes motor cortical output. Whether other variants of working memory have the same influence on motor output and whether the same neuronal circuits are involved is unknown. Therefore, the current study sought to investigate the influence of spatial working memory on different afferent projections converging on the corticospinal neuron in the motor cortex.
Short- (SAI) and long-latency afferent inhibition (LAI) were assessed in seventeen participants during the maintenance period of a spatial or verbal working memory task conducted over the course of two sessions per participant. Either session consisted of one of the two working memory tasks. In the spatial memory task, participants were required to encode a spatial array and maintain the array in working memory to determine whether a probe matched or did not match the original display. The probe consistent of a single dot and participants indicated whether the probe was part of the initial set. The spatial array consisted of either two or six dots around a central fixation cross. In the verbal memory task, participants were required to encode an array of letters and maintain the array in working memory to determine whether a probe matched or did not match the original display. The probe consistent of a single letter and participants indicated whether the probe was part of the initial set. The verbal set consisted of either two or six letters. The effect on different afferent circuits was assessed by manipulating the direction of induced current used in the assessment of SAI and LAI. The “PA” afferent circuit was recruited using TMS induced current in the posterior-anterior direction, and the “AP” afferent circuit was recruited using TMS induced current in the anterior-posterior direction. The order of task and current direction was randomized across participants with TMS current in each direction (AP/PA) conducted within both sessions. Baseline assessments of spatial and verbal working memory capacity evaluated the influence of working memory on sensorimotor circuits.
iv
Increasing verbal working memory load increased SAI from circuits recruited by current in the PA but not AP direction. Verbal working memory load had no impact on either PA or AP circuits mediating LAI. In contrast, spatial working memory load had no effect on either PA or AP circuits mediating SAI. Instead, increasing spatial working memory load increased LAI recruited by AP circuits.
These results suggest that spatial and verbal working memory influence the AP- and PA-mediated afferent circuits that converge on the corticospinal neuron to shape motor output. These different inputs may provide distinct pathways by which declarative knowledge can shape representations of motor skills
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
- …
