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Motor and cognitive development
Published in Miguel Pérez-Pereira, Gina Conti-Ramsden, Language Development and Social Interaction in Blind Children, 2019
Miguel Pérez-Pereira, Gina Conti-Ramsden
In addition, Rogers and Puchalski (1988) found no A-B errors in the blind children, unlike sighted children. As is well known, the A-B error consists in children searching a target object in the first place in which it was hidden (A), without taking into account the last displacement of the object to B. This difference in the performance of blind children is not easily interpretable as it is not clear that the tasks used by Rogers and Puchalski were equivalent to those used with sighted children, and which lead to the A-B error in sighted children. Furthermore, Rogers and Puchalski did not apply the task to a group of sighted children in order to compare the results with the group of blind children. Therefore Rogers and Puchalski’s findings are tentative with regard to this particular point, and we must be cautious in their interpretation.
Small-field dosimetry in megavoltage beams
Published in Indra J. Das, Radiochromic Film, 2017
The figure also shows the extrapolation estimate of the relative OF for a zero volume or area calculation that was found to be 0.651 ± 0.018 and 0.971 ± 0.017 for the 4 and 25 mm Brainlab cones, respectively. The extrapolation was performed using a second-order polynomial line of best fit to provide the best estimate at zero-volume OF. The variation in measured OF with different ROI areas is expected to change because of a number of reasons including profile shape of the beam and light-scattering properties within the scanner and film. The uncertainty values quoted in the figure and text are the standard deviation in measured results comparing the nine experimental films assessed for each cone size measured. These values combine both type A and type B errors associated with setup and dose delivery uncertainty along with experimental film-analysis errors combined. These results are in agreement with data provided by Garcia-Gurduno et al. [62] using four other detectors along with EBT and EBT2 films.
Calibration of Radiation Monitoring Instruments
Published in K. N. Govinda Rajan, Radiation Safety in Radiation Oncology, 2017
The variations in the repeatability of measurements are random variables and usually follow a normal or near normal distribution (called t distribution) and the sample standard deviation can be determined and a confidence limit (or interval) set for the average of these readings. Usually, a 95% confidence limit is set for the mean of the readings. The Type B errors are also treated in a similar manner though they are not exactly random in nature. By assuming a distribution for the Type B errors, kM’ can be treated as a standard deviation where M’ is the maximum value of the distribution and the value of k depends on the nature of the distribution assumed. For a rectangular distribution, k = 1/√3, and 1/√6 for a triangular distribution. Once the Type B errors are set as a standard deviation, the two types of errors can be added and a confidence limit set for the combined uncertainty. The accuracy is usually expressed as a percentage. If δH is the total uncertainty of the DE calibration factor of a monitor, set at 95% confidence level, the accuracy of the calibration factor, NH is given by [δH/NH) × 100%].
TDCS of the Primary Motor Cortex: Learning the Absolute Dimension of a Complex Motor Task
Published in Journal of Motor Behavior, 2021
Juliana Otoni Parma, Vitor Leandro da Silva Profeta, André Gustavo Pereira de Andrade, Guilherme Menezes Lage, Tércio Apolinário-Souza
Despite the recognized role of M1 in motor learning, little is known about the differential participation of M1 in the learning of the relative and absolute dimensions of motor skills. Studies investigating M1 participation in motor control and learning (Carmena et al., 2003; Churchland et al., 2006; Classen et al., 1998; Graziano et al., 2002; Shoham et al., 2005) do not use measures that permit distinguishing between the movement dimensions. They use a global measure that non-linearly encompasses both dimensions. In a behavioral study, Wulf et al. (1993) decompose for the first time the errors of movement execution into measures related to (a) errors in the stable dimension of the task, the relative dimension, and (b) errors in the flexible dimension of the task, the absolute dimension.
Awake prone positioning versus non invasive ventilation for COVID-19 patients with acute hypoxemic respiratory failure
Published in Egyptian Journal of Anaesthesia, 2021
We calculated the sample size consistent with our hospital data for non intubated oxygen-dependent COVID 19 pneumonia as 8of 20 patients (40%) need critical care admission. Our recording data suggest that just one out of ten patients required intubation, calculations a total sample size 30;15 in each group indicated a confidence level 90% (α- error = 0.05,B-error = 0.2). Descriptive variables are expressed as percentage, mean and stander deviation (SD), or median and interquartile range (IQR), as appropriate for every variable. We used the student t test or Mann–Whitney test for numerical variables and chi-squared test or Fisher exact test for categorical variables, to match variables across the two group. Missing data weren’t imputed. Analyses were performed on an entire case analysis basis. All tests were two-sided, and a P -value < 0.05 was considered statistically significant. All analyses were performed with SPSS version 23.
Null strain analysis of submerged aneurysm analogues using a novel 3D stereomicroscopy device
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2020
Brooks A. Lane, Susan M. Lessner, Narendra R. Vyavahare, Michael A. Sutton, John F. Eberth
In this paper, we present our design and baseline validation results for a novel StereoDIC device used to gather full-field 360° information from submerged specimens with commonly observed healthy and aneurysmal geometries (e.g., cylindrical, fusiform and saccular shapes) of similar length scales to murine or small human cerebral vessels (1.0 to 4.0 mm). In a cost- and experimentally-efficient manner, we utilize two radially fixed and vertically stacked stereo cameras, rather than a fixed multi-camera system, on a motor-controlled rotational stage to gather images of a centrally located specimen submerged in an octagonal aqueous bath. Much like the function of x-ray computed tomography (CT), our imaging platform revolves around the specimen, thereby minimizing the camera and lens costs while reducing viscous and inertial effects that occur when rotating the specimen. Here we calibrate the system and examine the resultant bias and error in shape reconstruction and strain analysis of submerged rigid bodies subjected to translations and rotations using our unique camera system. Designated as null-strain analysis for the remainder of the article, the experimental results for the rigid body motions include (a) temporal effects for a fixed translation/rotation, (b) errors originating from stereo-rig rotation, and errors due to image analysis of both simple and complex shapes. Understanding these measurement errors is necessary to validate the stereomicroscopy device for displacement and strain measurements of micro-aneurysms to ensure that incorporated errors are minimal compared to anticipated experimental deformations.