11,967 research outputs found
Theta synchronization over occipito‐temporal cortices during visual perception of body parts
Categorical clustering in the visual system is thought to have evolved as a function of intrinsic (intra-areal) and extrinsic (interareal) connectivity and experience. In the visual system, the extrastriate body area (EBA), an occipito-temporal region, responds to full body and body part images under the organizational principle of their functional/semantic meaning. Although frequency-specific modulations of neural activity associated with perceptive and cognitive functions are increasingly attracting the interest of neurophysiologists and cognitive neuroscientists, perceiving single body parts with different functional meaning and full body images induces time-frequency modulations over occipito-temporal electrodes are yet to be described. Here, we studied this issue by measuring EEG in participants who passively observed fingers, hands, arms and faceless full body images with four control plant stimuli, each bearing hierarchical analogy with the body stimuli. We confirmed that occipito-temporal electrodes (compatible with the location of EBA) show a larger event-related potential (ERP, N190) for body-related images. Furthermore, we identified a body part-specific (i.e. selective for hands and arms) theta event-related synchronization increase under the same electrodes. This frequency modulation associated with the perception of body effectors over occipito-temporal cortices is in line with recent findings of categorical organization of neural responses to human effectors in the visual system
Microwave magnetoplasmon absorption by a 2DEG stripe
Microwave absorption by a high mobility 2DEG has been investigated
experimentally using sensitive Electron Paramagnetic Resonance cavity
technique. It is found that MW absorption spectra are chiefly governed by
confined magnetoplasmon excitations in a 2DEG stripe. Spectra of the 2D
magnetoplasmons are studied as a function of magnetic field, MW frequency and
carrier density. The electron concentration is tuned by illumination and
monitored using optical photoluminescence technique.Comment: to be published in International Journal of Modern Physics
The scenario of two-dimensional instabilities of the cylinder wake under EHD forcing: A linear stability analysis
We propose to study the stability properties of an air flow wake forced by a dielectric barrier discharge (DBD) actuator, which is a type of electrohydrodynamic (EHD) actuator. These actuators add momentum to the flow around a cylinder in regions close to the wall and, in our case, are symmetrically disposed near the boundary layer separation point.
Since the forcing frequencies, typical of DBD, are much higher than the natural shedding frequency of the flow, we will be considering the forcing actuation as stationary.
In the first part, the flow around a circular cylinder modified by EHD actuators will be experimentally studied by means of particle image velocimetry (PIV). In the second part, the EHD actuators have been numerically implemented as a boundary condition on the cylinder surface. Using this boundary condition, the computationally obtained base flow is then compared with the experimental one in order to relate the control parameters from both methodologies.
After validating the obtained agreement, we study the Hopf bifurcation that appears once the flow starts the vortex shedding through experimental and computational approaches. For the base flow derived from experimentally obtained snapshots, we monitor the evolution of the velocity amplitude oscillations. As to the computationally obtained base flow, its stability is analyzed by solving a global eigenvalue problem obtained from the linearized Navier–Stokes equations. Finally, the critical parameters obtained from both approaches are compared
Dorset Site Variation on the Southeast Coast of Baffin Island
The wide variation in Dorset residence structures may indicate seasonal site differences greater than a simple summer/winter dichotomy. This is further suggested by a comparison of selected stone tool frequencies from Dorset sites near Lake Harbour, N.W.T. Here manufacturing activities appear to differ from spring to summer to winter. The evidence also suggests that in this region Late Dorset winter settlements were located on the fast sea ice
A Southeastern Baffin Thule House with Ruin Island Characteristics
A prehistoric house depression excavated on the southeastern coast of Baffin Island near Lake Harbour belongs stylistically to an early phase of the Thule Period. However, features such as the rectangular shape, interior open-fire kitchens, and initial absence of a sleeping platform are more characteristic of the early High Arctic Ruin Island phase than of developed Thule. This, and additional evidence from Foxe Basin and Frobisher Bay, suggest that a segment of the earliest Thule migration may have split from the main body in Lancaster Sound and, travelling south through Fury and Helca Strait, reached Hudson Strait and the south coast of Baffin Island. This suggestion is in opposition to earlier interpretations of a slow penetration into the more southerly eastern part of the Canadian Archipelago from the northeastern High Arctic
Ncaa Division-I Student Athletes\u27 Lived Experiences of An in-Season Concussion
An estimated 1.6-3.8 million people suffer a concussion annually in the United States. Concussions are becoming an increasingly mainstream topic, especially with the amount coverage of concussions in different media outlets. Furthermore, peers such as athletic trainers, friends, coaches, and parents that may influence their experience of concussions. The purpose of this study was to examine NCAA Division I student-athletes\u27 lived experiences of an in-season concussion. A phenomenological approach was used. The following open-ended question was asked: Can you tell me about your experience of having your most recent concussion? The research participants consisted of 4 in-season collegiate student-athletes, 18-21 years old. The participants were withheld from activity per the institution\u27s concussion policy and interviewed within six months of their return to play. Interviews were tape recorded, transcribed, and analyzed. Pseudonyms were used to ensure participant anonymity and confidentiality. The researcher used triangulation to maintain validity by using member checks, peer reviews, other members of the research team, a bracketing interview. 6 major themes developed from the research including: Focus on Symptoms, Emotional Response to Injury, Experiences of Concussion Testing, Fear of Failing to Meet Teammate Expectations, Support From Friends and Family, and Effect on School. Emotional Response to Injury and Symptoms were the most prevalent themes with their experiences following suit with previous research. Some participants seemed to struggle with schoolwork, which supports the cognitive rest theories that are currently being used to help treat concussions in some areas. Overall concussions are very individualized injuries and athletic trainers should be aware of athletes\u27 personalities and use compassion to help them recover from their concussion
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