Breaking the Pressure Barrier: A History of the Spacesuit Injection Patch

The spacesuit assembly has a fascinating and complicated history dating back to the early 1930s. Much has been written on this history from an assembly perspective and, to a lesser extent, a component perspective. However, little has been written or preserved specifically on smaller, lesser-known aspects of pressure suit design. One example of this is the injection patch - a small 2-in.-diameter disk on the leg of the Apollo suit that facilitated a medical injection when pressurized, and the only known implementation of such a feature on a flight suit. Whereas many people are aware this feature existed, very little is known of its origin, design, and use, and the fact that the Apollo flight suit was not the only instance in which such a feature was implemented. This paper serves to tell the story of this seeming "afterthought" of a feature, as well as the design considerations heeded during the initial development of subsequent suits

Evaluation of Hand-to-Hand Bioelectrical Impedance Analysis for Estimating Percent Body Fat in Young Adults

Purposes were to (a) to examine the validity and precision of a hand-to-hand bioelectrical impedance analyzer (HBIA) and (b) to determine the effect of an acute sub-maximal aerobic exercise bout on HBIA percent body fat (%BF) measures. Forty-one young adults (21 women; 20 men) visited the laboratory for body composition assessment on two separate occasions. During the control session, %BF was assessed by HBIA twice, before and immediately after 30 min of rest, and once by air-displacement plethysmography (ADP), using the BOD POD, which was considered the criterion method for comparison. During the exercise session, HBIA %BF measurements were determined prior-to and immediately after 30 minutes of moderate-intensity treadmill exercise. HBIA significantly underestimated %BF in the total sample (mean difference (MD) = 1.4 ± 4.3%) and, when examined by gender, in the women (MD = 2.4 ± 4.1%). The standard errors of estimate (range 4.1-4.3%) also exceeded the recommended range for accuracy (\u3c3.5%). Following exercise, there was minimal, but statistically significant reduction in HBIA-measured %BF pre- to post-exercise for the total sample (19.6 ± 6.0 vs. 19.3 ± 6.0%; p = 0.011). HBIA underestimated %BF when compared to ADP and the individual prediction error exceeded current recommendations when assessing young adults. In addition, performing sub-maximal aerobic exercise prior to the assessment decreased the %BF estimate. When one factors the exercise-induced alterations with the currently observed tendency for HBIA to underestimate %BF, it is apparent that exercise may further reduce the accuracy of this method

Ultrasound-determined diameter measurements are more accurate than axial computed tomography after endovascular aortic aneurysm repair

ObjectiveThis study evaluated the correlation of ultrasound (US)-derived aortic aneurysm diameter measurements with centerline, three-dimensional (3-D) reconstruction computed tomography (CT) measurements after endovascular aortic aneurysm repair (EVAR).MethodsConcurrent CT and US examinations from 82 patients undergoing post-EVAR surveillance were reviewed. The aortic aneurysm diameter was defined as the major axis on the centerline images of 3-D CT reconstruction. This was compared with US-derived minor and major axis measurements, as well as with the minor axis measurement on the conventional axial CT images. Correlation was evaluated with linear regression analyses. Agreement between different imaging modalities and measurements was assessed with Bland-Altman plots.ResultsThe correlation coefficients from linear regression analyses were 0.92 between CT centerline major and US minor measurements, 0.94 between CT centerline major and US major measurements, and 0.93 between CT minor and centerline major measurements. Bland-Altman plots showed a mean difference of 0.11 mm between US major and CT centerline measurements compared with 5.38 mm between US minor and CT centerline measurements, and 4.25 mm between axial CT minor and centerline measurements. This suggested that, compared with axial CT and US minor axis measurements, US major axis measurements were in better agreement with CT centerline measurements. Variability between major and minor US and CT centerline diameter measurements was high (standard deviation of difference, 4.27-4.84 mm). However, high variability was also observed between axial CT measurements and centerline CT measurements (standard deviation of difference, 4.36 mm).ConclusionsThe major axis aneurysm diameter measurement obtained by US imaging for surveillance after EVAR correlates well and is in better agreement with centerline 3-D CT reconstruction diameters than axial CT

Trends in the Management of Small Renal Masses: A Survey of Members of the Endourological Society

Treatment modalities for small renal masses (SRMs) include open or minimally invasive radical or partial nephrectomy, and laparoscopic or percutaneous ablations. Members of the Endourological Society were surveyed to evaluate how practitioner and clinical practice characteristics may be associated with the management of SRMs over time. The survey assessed characteristics of urologists (recency of residency and fellowship training, clinical practice type and location, and treatment modalities available) and their management of SRMs over the past year and over the course of the year 5 years prior. Of the 1495 surveys e-mailed, there were 129 respondents (8.6%). Comparing the past year to 5 years prior, there was increasing utilization of robotic partial nephrectomy (p < 0.001) and robotic radial nephrectomy (p = 0.031). In contrast, there was decreasing utilization of open partial nephrectomy (p < 0.001), open radical nephrectomy (p = 0.039), laparoscopic partial nephrectomy (p = 0.002), and laparoscopic radical nephrectomy (p = 0.041). Employment of laparoscopic ablation decreased (p = 0.001), but that of percutaneous ablation did not change significantly. For masses treated with image-guided therapy, there was increasing utilization of microwave ablation (p = 0.008) and decreasing usage of radiofrequency ablation (p = 0.002). Future studies should focus on the most effective treatment modalities based on provider, patient, and tumor characteristics

Detecting and Characterizing Mg II absorption in DESI Survey Validation Quasar Spectra

In this paper we will present findings on the detection of Magnesium II (MgII, lambda = 2796 {\AA}, 2803 {\AA}) absorption systems observed in data from the Early Data Release (EDR) of the Dark Energy Spectroscopic Instrument (DESI). DESI is projected to obtain spectroscopy of approximately 3 million quasars (QSOs), of which over 99% are anticipated to be found at redshifts greater than z < 0.3, such that DESI would be able to observe an associated or intervening Mg II absorber illuminated by the background QSO. We have developed an autonomous supplementary spectral pipeline that detects such systems through an initial line-fitting process and then confirms line properties using a Markov Chain Monte Carlo (MCMC) sampler. Based upon both a visual inspection and the reanalysis of coadded observations, we estimate this sample of absorption systems to have a completeness of 82.56% and purity of 99.08%. As the spectra in which Mg II systems are detected are the result of coadding multiple observations, we can determine the sensitivity, and therefore completeness, of the sample by searching for known Mg II systems in coadded data with fewer observations (and therefore lower signal-to-noise). From a parent catalog containing 83,207 quasars, we detect a total of 23,921 Mg II absorption systems following a series of quality cuts. Extrapolating from this occurrence rate of 28.75% implies a catalog at the completion of the five-year DESI survey that contains over eight hundred thousand Mg II absorbers. The cataloging of these systems will enable significant further research as they carry information regarding circumgalactic medium (CGM) environments, the distribution of intervening galaxies, and the growth of metallicity across the redshift range 0.3 < z < 2.5.Comment: 12 pages, 7 figure

An empirical analysis of the determinants of mobile instant messaging appropriation in university learning

Published ArticleResearch on technology adoption often profiles device usability (such as perceived usefulness) and user dispositions (such as perceived ease of use) as the prime determinants of effective technology adoption. Since any process of technology adoption cannot be conceived out of its situated contexts, this paper argues that any pre-occupation with technology acceptance from the perspective of device usability and user dispositions potentially negates enabling contexts that make successful adoption a reality. Contributing to contemporary debates on technology adoption, this study presents flexible mobile learning contexts comprising cost (device cost and communication cost), device capabilities (portability, collaborative capabilities), and learner traits (learner control) as antecedents that enable the sustainable uptake of emerging technologies. To explore the acceptance and capacity of mobile instant messaging systems to improve student performance, the study draws on these antecedents, develops a factor model and empirically tests it on tertiary students at a South African University of Technology. The study involved 223 national diploma and bachelor’s degree students and employed partial least squares for statistical analysis. Overall, the proposed model displayed a good fit with the data and rendered satisfactory explanatory power for students’ acceptance of mobile learning. Findings suggest that device portability, communication cost, collaborative capabilities of device and learner control are the main drivers of flexible learning in mobile environments. Flexible learning context facilitated by learner control was found to have a positive influence on attitude towards mobile learning and exhibited the highest path coefficient of the overall model. The study implication is that educators need to create varied learning opportunities that leverage learner control of learning in mobile learning systems to enhance flexible mobile learning. The study also confirmed the statistical significance of the original Technology Acceptance Model constructs

The Spectroscopic Data Processing Pipeline for the Dark Energy Spectroscopic Instrument

We describe the spectroscopic data processing pipeline of the Dark Energy Spectroscopic Instrument (DESI), which is conducting a redshift survey of about 40 million galaxies and quasars using a purpose-built instrument on the 4-m Mayall Telescope at Kitt Peak National Observatory. The main goal of DESI is to measure with unprecedented precision the expansion history of the Universe with the Baryon Acoustic Oscillation technique and the growth rate of structure with Redshift Space Distortions. Ten spectrographs with three cameras each disperse the light from 5000 fibers onto 30 CCDs, covering the near UV to near infrared (3600 to 9800 Angstrom) with a spectral resolution ranging from 2000 to 5000. The DESI data pipeline generates wavelength- and flux-calibrated spectra of all the targets, along with spectroscopic classifications and redshift measurements. Fully processed data from each night are typically available to the DESI collaboration the following morning. We give details about the pipeline's algorithms, and provide performance results on the stability of the optics, the quality of the sky background subtraction, and the precision and accuracy of the instrumental calibration. This pipeline has been used to process the DESI Survey Validation data set, and has exceeded the project's requirements for redshift performance, with high efficiency and a purity greater than 99 percent for all target classes.Comment: AJ, revised version, 55 pages, 55 figures, 4 table

Dissection of QTL effects for root traits using a chromosome arm-specific mapping population in bread wheat

A high-resolution chromosome arm-specific mapping population was used in an attempt to locate/detect gene(s)/QTL for different root traits on the short arm of rye chromosome 1 (1RS) in bread wheat. This population consisted of induced homoeologous recombinants of 1RS with 1BS, each originating from a different crossover event and distinct from all other recombinants in the proportions of rye and wheat chromatin present. It provides a simple and powerful approach to detect even small QTL effects using fewer progeny. A promising empirical Bayes method was applied to estimate additive and epistatic effects for all possible marker pairs simultaneously in a single model. This method has an advantage for QTL analysis in minimizing the error variance and detecting interaction effects between loci with no main effect. A total of 15 QTL effects, 6 additive and 9 epistatic, were detected for different traits of root length and root weight in 1RS wheat. Epistatic interactions were further partitioned into inter-genomic (wheat and rye alleles) and intra-genomic (rye–rye or wheat–wheat alleles) interactions affecting various root traits. Four common regions were identified involving all the QTL for root traits. Two regions carried QTL for almost all the root traits and were responsible for all the epistatic interactions. Evidence for inter-genomic interactions is provided. Comparison of mean values supported the QTL detection

The DESI survey validation : results from visual inspection of bright galaxies, luminous red galaxies, and emission line galaxies

Funding: TWL was supported by the Ministry of Science and Technology (MOST 111-2112-M-002-015-MY3), the Ministry of Education, Taiwan (MOE Yushan Young Scholar grant NTU-110VV007), National Taiwan University research grants (NTU CC-111L894806, NTU- 111L7318), and NSF grant AST-1911140. DMA acknowledges the Science Technology and Facilities Council (STFC) for support through grant code ST/T000244/1. This research is supported by the Director, Office of Science, Office of High Energy Physics of the U.S. Department of Energy under Contract No. DE–AC02–05CH11231, and by the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility under the same contract; additional support for DESI is provided by the U.S. National Science Foundation, Division of Astronomical Sciences under Contract No. AST-0950945 to the NSF’s National Optical-Infrared Astronomy Research Laboratory; the Science and Technologies Facilities Council of the United Kingdom; the Gordon and Betty Moore Foundation; the Heising-Simons Foundation; the French Alternative Energies and Atomic Energy Commission (CEA); the National Council of Science and Technology of Mexico (CONACYT); the Ministry of Science and Innovation of Spain (MICINN), and by the DESI Member Institutions: https://www.desi.lbl.gov/ collaborating-institutions.The Dark Energy Spectroscopic Instrument (DESI) Survey has obtained a set of spectroscopic measurements of galaxies for validating the final survey design and target selections. To assist these tasks, we visually inspect (VI) DESI spectra of approximately 2,500 bright galaxies, 3,500 luminous red galaxies, and 10,000 emission line galaxies, to obtain robust redshift identifications. We then utilize the VI redshift information to characterize the performance of the DESI operation. Based on the VI catalogs, our results show that the final survey design yields samples of bright galaxies, luminous red galaxies, and emission line galaxies with purity greater than 99%. Moreover, we demonstrate that the precision of the redshift measurements is approximately 10 km/s for bright galaxies and emission line galaxies and approximately 40 km/s for luminous red galaxies. The average redshift accuracy is within 10 km/s for the three types of galaxies. The VI process also helps to improve the quality of the DESI data by identifying spurious spectral features introduced by the pipeline. Finally, we show examples of unexpected real astronomical objects, such as Lyman α emitters and strong lensing candidates, identified by VI. These results demonstrate the importance and utility of visually inspecting data from incoming and upcoming surveys, especially during their early operation phases.Publisher PDFPeer reviewe