1,375 research outputs found

    Accelerometer measurements to characterize drag profiles in the mesosphere

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    This project will verify the capabilities of an accelerometer for launch aboard suborbitalvehicles. If our prototype reliably produces data with ample resolution, it can be used to study the mesosphere and the reentry of suborbital vehicles. With partial support from NASA\u27s Low Cost Access to Space Program, we hope to provide drag data on free-falling vehicles in the mesosphere. Our set up consists of a 3-axis accelerometer in a 10 cm CubeSat and a 12 bit data logger at 1024 Hz sampling rate. With zero-g environment data, we apply spectral analysis to find the amplitude of each frequency in our signal. In our testing phase this will be used to characterize noise present in the device while in a rocket test this will tell us how drag on the vehicle affects the rocket\u27s flight. Once we are satisfied with the behavior of the instrument and understand the voltage outputs adequately, we plan to prepare a report to XCOR Aerospace to fly our instrument on the Lynx suborbital space plane

    Accuracy of Wrist-Worn Monitors while Walking in Lower Limb Prosthetic Users

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    TACSM Abstract Accuracy of Wrist-Worn Monitors while Walking in Lower Limb Prosthetic Users BRIAN G. BURKHOLDER and JOHN D. SMITH Department of Counseling, Health, & Kinesiology, Texas A&M University-San Antonio, San Antonio, TX Category: Undergraduate Advisor / Mentor: Smith, John ([email protected]) ABSTRACT Wrist-worn activity monitors are extremely popular among the general population. These monitors are used to track activity for purposes to lose weight, get healthy, improve performance, and other reasons. While many studies have looked at the accuracy of these monitors in individuals without amputations, there has yet to be any that have examined these monitors in those who use lower-limb prosthetics. PURPOSE: to determine the accuracy of wrist-worn activity monitors in individuals using lower-limb prosthetics. METHODS: Thirty-four men and women (Age: 48.8±14.2 yrs, Ht: 176.9±11.5 cm, Wt: 88.3±21.1 kg, BMI: 28.3±5.3) with right-, left-leg, or bilateral above and below the knee amputations were fitted with a Polar Loop (PL) and a Fitbit ChargeTM (FC) on the left wrist, and an Omron HJ-112 (OM) pedometer on the left hip. After resetting the monitors, they then walked 140m at a self-selected pace followed by the investigator who counted steps with a standard lab hand-tally counter for actual counts (AC). At the conclusion of the walk, step counts were recorded from all devices. A repeated measures ANOVA was used to determine differences in counts registered by the monitors and those registered by AC. Single measure intraclass correlation (ICC) from a two-way random effects ANOVA was used to assess the agreement between AC and monitor counts, with ≥ 0.90 considered high agreement, 0.80 to 0.89 moderate agreement, and ≤ 0.79 low agreement. Bland-Altman plots of AC vs. counts registered by the monitors were used to provide an indication of over/under representation of steps and agreement between the measures. Percent error was calculated as [(counts detected by monitor – AC) / AC] x 100. Alpha was set at .05 for all statistical tests. RESULTS: There was a significant difference between counts, F(3, 30)=8.8, p=.001, with pairwise comparisons indicating PL was significantly lower than AC, p=.001. There was no significant difference between AC and FC (p\u3e.05) or between AC and OM (p\u3e.05). Agreement according to ICC between AC and PL was low (α=.71, ICC=.42 to .86), between AC and FC was moderate (α =.81, ICC=.61 to .90), and between AC and OM was high (α =.93, ICC=.86 to .97). Bland Altman plots indicate lowest agreement between AC and PL, and with highest agreement between AC and OM. Percent error was greatest with PL (16±12%), lower with FC (8.9±8.9%), and least with OM (4.1±7.3%). CONCLUSION: It seems that for this population who might consider wearing either the PL or the FC, the FC would be a better choice given its greater accuracy. Interestingly, the OM is the superior device for counting steps

    Visualizing Affine Regular, Area-Preserving Decompositions of Irregular 3D Pentagons and Heptagons

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    Abstract We demonstrate a simple, elegant, and visual method for decomposing irregular pentagons into a pair of affine images of the two distinct types of regular pentagons. Moreover, the sum of the area of the two affine images equals the area of the original irregular pentagon. Similarly, we decompose irregular heptagons into a triple of affine images of the three distinct types of regular heptagons. One can use these decompositions to design visually interesting sculptures reflecting these geometric relationships

    Higher education, HLRC, pandemics, and racism

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    Indexación: Scopus.This letter from the Editorial team discusses the context of HLRC journal operations during the period from January 1, 2020, to June 30, 2020. The editors discuss COVID-19, race-related uprisings, and how these have impacted the journal in the context of higher education.https://scholarworks.waldenu.edu/hlrc/vol10/iss1/7

    The Standardized Fish Bioassay Procedure for Detecting and Culturing Actively Toxic Pfiesteria, Used by Two Reference Laboratories for Atlantic and Gulf Coast States

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    In the absence of purified standards of toxins from Pfiesteria species, appropriately conducted fish bioassays are the gold standard that must be used to detect toxic strains of Pfiesteria slop. from natural estuarine water or sediment samples and to culture actively toxic Pfiesteria. In this article, we describe the standardized steps of our fish bioassay as an abbreviated term for a procedure that includes two sets of trials with fish, following the Henle-Koch postulates modified for toxic rather than infectious agents. This procedure was developed in 1991, and has been refined over more than 12 years of experience in research with toxic Pfiesteria. The steps involve isolating toxic strains of Pfiesteria (or other potentially, as-yet-undetected, toxic Pfiesteria or Pfiesteria-like species) from fish-killing bioassays with natural samples; growing the clones with axenic algal prey; and retesting the isolates in a second set of fish bioassays. The specific environmental conditions used (e.g., temperature, salinity, light, other factors) must remain flexible, given the wide range of conditions from which natural estuarine samples are derived. We present a comparison of information provided for fish culture conditions, reported in international science journals in which such research is routinely published, and we provide information from more than 2,000 fish bioassays with toxic Pfiesteria, along with recommendations for suitable ranges and frequency of monitoring of environmental variables. We present data demonstrating that algal assays, unlike these standardized fish bioassays, should not be used to detect toxic strains of Pfiesteria spp. Finally, we recommend how quality control/assurance can be most rapidly advanced among laboratories engaged in studies that require research-quality isolates of toxic Pfiesteria spp
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