Homogeneity in Motor Competence Among Youths With Intellectual Disability With and Without Down Syndrome.

PURPOSE: To determine if there is a homogeneity of scores for youth with intellectual disability (ID) with and without Down syndrome (DS) in 19 test items of motor competence from the Bruininks-Oseretsky Test of Motor Proficiency-Second Edition (BOT-2). Homogeneity was defined as the means for each of the 19 test items scores by sex and the presence or absence of DS sharing the same population mean. METHOD: Participants were 622 youth with ID aged 6 to 21 years. Items for bilateral coordination, balance, and upper limb coordination were examined using the BOT-2. RESULTS: For all 19 BOT-2 items, means between youth with and without DS did not differ from the population mean. CONCLUSION: These results potentiate the development of expected BOT-2 motor competence scores for youth with ID independent of the presence of DS for clinical practice.

Temperature dependent performance of Schmidt-Boelter heat flux sensors.

The total heat flux sensors for NASA's Mars Entry, Descent, and Landing Instrumentation 2 (MEDLI2) sensor suite on the Mars 2020 vehicle and the Low-Earth Orbit Flight Test of an Inflatable Decelerator (LOFTID) technology demonstration mission are passively cooled Schmidt-Boelter gauges. The output of these sensors has been experimentally demonstrated to be dependent on the temperature of the sensing element. The experimental results are shown to align with a model that assumes temperature-dependent material properties, specifically the Seebeck coefficient. The MEDLI2 and LOFTID flight total heat flux sensors did not undergo a full thermal calibration prior to being installed on the flight vehicles since the temperature dependence was unknown ahead of time. Additionally, the material properties are not known due to the designs being proprietary. For these reasons, an approximate correction factor was derived. The applicability and associated uncertainty of this temperature-dependent correction factor are presented. The error that would be introduced into the measurement if temperature effects were not accounted for would be as high as 9.5% and 16% for the MEDLI2 and LOFTID total heat flux sensors, respectively. As a best practice for future flight missions and ground-based applications that employ similar passively cooled heat flux sensors, it is recommended to individually calibrate each sensor across all applicable use temperatures to account for sensor-to-sensor variations and minimize measurement uncertainty.

Comparing Motor Competence of Sex- and Age-Matched Youth With Intellectual Disability From Brazil and the United States.

Youth with intellectual disabilities (IDs) demonstrate below-criteria motor competence (MC) compared with typically developing (TD) youth. Whether differences in MC exist for youth with ID from different countries is unknown. This study examined the MC of youth with ID from Brazil (BR) and the United States (US) and compared it with norms for TD youth as established by the Bruininks-Oseretsky Test of Motor Proficiency (BOT-2). The authors measured 19 BOT-2 test items for bilateral coordination, balance, and upper limb coordination of 502 youth (BR = 252, US = 250) with ID (6-21 years). Raw scores were converted to %ceiling (percentile of highest expected scores). For all test items, no significant differences were seen between BR and US participants in %ceiling scores. Participants from both countries demonstrated equivalent to slightly below BOT-2 norms in 14 of the 19 test items, with lowest scores seen in contralateral synchronizing bilateral coordination, balancing on one leg, and ball handling.

Characterization of the piezoresistance in highly doped p-type 3C-SiC at cryogenic temperatures.

This paper reports on the piezoresistive effect in p-type 3C-SiC thin film mechanical sensing at cryogenic conditions. Nanothin 3C-SiC films with a carrier concentration of 2 × 1019 cm-3 were epitaxially grown on a Si substrate using the LPCVD process, followed by photolithography and UV laser engraving processes to form SiC-on-Si pressure sensors. The magnitude of the piezoresistive effect was measured by monitoring the change of the SiC conductance subjected to pressurizing/depressurizing cycles at different temperatures. Experimental results showed a relatively stable piezoresistive effect in the highly doped 3C-SiC film with the gauge factor slightly increased by 20% at 150 K with respect to that at room temperature. The data was also in good agreement with theoretical analysis obtained based on the charge transfer phenomenon. This finding demonstrates the potential of 3C-SiC for MEMS sensors used in a large range of temperatures from cryogenic to high temperatures.

In situ ultraviolet shock radiance measurements using GaN-on-sapphire photodetectors.

Gallium nitride (GaN)-on-sapphire photodetectors are used to measure the ultraviolet (UV) radiance behind a shock wave in support of atmospheric entry sensing technologies. DC spectral response characterization of the GaN-based photodetectors shows a peak response around 365 nm with an UV/visible rejection of an order of magnitude. To conduct in situ measurements of UV shock-layer radiation, the GaN-based photodetectors were installed, without protective packaging, in the test section of a shock tube. The measured UV radiation, in terms of incident optical power on the photodetectors, is in excellent agreement with average UV radiation measured by the shock tube facility spectrometers. Furthermore, the device response after being subjected to the shock wave is unaltered, suggesting that the GaN-based material platform is suitable for implementation in aerospace and other harsh environment sensing applications.

A microfabricated sun sensor using GaN-on-sapphire ultraviolet photodetector arrays.

A miniature sensor for detecting the orientation of incident ultraviolet light was microfabricated using gallium nitride (GaN)-on-sapphire substrates and semi-transparent interdigitated gold electrodes for sun sensing applications. The individual metal-semiconductor-metal photodetector elements were shown to have a stable and repeatable response with a high sensitivity (photocurrent-to-dark current ratio (PDCR) = 2.4 at -1 V bias) and a high responsivity (3200 A/W at -1 V bias) under ultraviolet (365 nm) illumination. The 3 × 3 GaN-on-sapphire ultraviolet photodetector array was integrated with a gold aperture to realize a miniature sun sensor (1.35 mm × 1.35 mm) capable of determining incident light angles with a ±45° field of view. Using a simple comparative figure of merit algorithm, measurement of incident light angles of 0° and 45° was quantitatively and qualitatively (visually) demonstrated by the sun sensor, supporting the use of GaN-based sun sensors for orientation, navigation, and tracking of the sun within the harsh environment of space.