Use of new developments on attitude control sensors for the microsatellite Flying Laptop

The Flying Laptop is a micro-satellite currently under development at the Institute of Space Systems, Universität Stuttgart. The primary mission objective of the Flying Laptop is technology demonstration for the future projects of the Institute of Space Systems. Several attitude sensors, either in-house developed or from external companies with no previous flight heritage, are being used. Electronic boards and mechanical housings were designed for the GPS system, the fiber-optic gyros and the magnetic torquers. The GENIUS experiment aims to increase the GPS accuracy in orbit by using an ultra stable oscillator (USO) and includes attitude determination. The C-FORS fiber optic gyro is a commercial product developed for aviation. With the Micro Advanced Stellar Compass made by the Technical University of Denmark and the Magnetometer made by Zarm-Technik new developments, so far not flown, are integrated. All attitude sensors and actuators are connected to a field programmable gate array (FPGA). This kind of onboard computer offers a more accurate timing and parallel processing of the sensors' and actuators' signals. The paper focuses on the attitude sensors and actuators and their interfaces to the on-board computer

Application of a Parametric Level-Set Approach to Topology Optimization of Fluids with the Navier–Stokes and Lattice Boltzmann Equations

Traditional material distribution based methods applied to the topology optimization of fluidic systems often suffer from rather slow convergence. The local influence of the design variables in the traditional material distribution based approaches is seen as the primary cause, leading to small gradients which cannot drive the optimization process sufficiently. The present work is an attempt to improve the rate of convergence of topology optimization methods of fluidic systems by employing a parametric level-set function coupled with a topology description approach. Using level-set methods, a global impact of design variables is achieved and the material description is decoupled from the flow field discretization. This promises to improve the gradients with respect to the design variables and can be applied to rather different types of fluid formulations and discretization methods. In the present work, a finite element method for solving the Navier-Stokes equations and a hydrodynamic finite difference lattice Boltzmann method are considered. Using a 2D example the parametric level-set approach is validated through comparison with traditional material distribution based methods. While the parametric level-set approach leads to the desired optimal designs and has advantages such as improved modularity and smoothness of design boundaries when compared to material distribution based methods, the present study does not reveal improvements for the convergence of the optimization problem

WP 2018-389

Recent research has found, in some groups of Americans, dramatic increases in deaths due to drug overdose and suicide and an overall stagnation of trends toward increased longevity. This study examines the link between mortality of older working age (45 to 64) adults and local economic downturns in the U.S. to evaluate the role of economic shifts in various causes of death and their related mortality trends. Specifically, we estimate regression models to test the hypotheses that the longevity effects of poor economic prospects are reflected through (1) increased suicide, drug overdose, and other “deaths of despair” and (2) other causes of death linked to exposure to economic and social stress such as heart and cerebrovascular disease. To avoid the problem of endogeneity of local economic conditions to mortality conditions, we measure the local economic shock of lost employment with predicted employment based on baseline industrial composition and national trends in employment by industry. We find evidence consistent with prior research that among non-Hispanic white adults, midlife mortality has increased since 1990, particularly among those with low educational attainment. We also find that “deaths of despair” are important contributors to that trend. However, we find that while distress in local, area economies does predict increased mortality for chronic disease, it predicts decreased mortality from suicides, opioids, and other substance abuse. This finding suggests caution in the application of the construct of despair in explaining recent mortality patterns.Social Security Adminstration, Award number RRC08098401-10, R-UM18-07https://deepblue.lib.umich.edu/bitstream/2027.42/148126/1/wp389.pdfDescription of wp389.pdf : Working pape

Heterogeneity in Health Insurance Coverage Among US Latino Adults

We sought to determine the differences in observed and unobserved factors affecting rates of health insurance coverage between US Latino adults and US Latino adults of Mexican ancestry. Our hypothesis was that Latinos of Mexican ancestry have worse health insurance coverage than their non-Mexican Latino counterparts. The National Health Interview Survey (NHIS) database from 1999–2007 consists of 33,847 Latinos. We compared Latinos of Mexican ancestry to non-Mexican Latinos in the initial descriptive analysis of health insurance coverage. Disparities in health insurance coverage across Latino categories were later analyzed in a multivariable logistic regression framework, which adjusts for confounding variables. The Blinder-Oaxaca technique was applied to parse out differences in health insurance coverage into observed and unobserved components. US Latinos of Mexican ancestry consistently had lower rates of health insurance coverage than did US non-Mexican Latinos. Approximately 65% of these disparities can be attributed to differences in observed characteristics of the Mexican ancestry population in the US (e.g., age, sex, income, employment status, education, citizenship, language and health condition). The remaining disparities may be attributed to unobserved heterogeneity that may include unobserved employment-related information (e.g., type of employment and firm size) and behavioral and idiosyncratic factors (e.g., risk aversion and cultural differences). This study confirmed that Latinos of Mexican ancestry were less likely to have health insurance than were non-Mexican Latinos. Moreover, while differences in observed socioeconomic and demographic factors accounted for most of these disparities, the share of unobserved heterogeneity accounted for 35% of these differences

Ulcerative colitis and irritable bowel patients exhibit distinct abnormalities of the gut microbiota

<p>Abstract</p> <p>Background</p> <p>Previous studies suggest a link between gut microbiota and the development of ulcerative colitis (UC) and irritable bowel syndrome (IBS). Our aim was to investigate any quantitative differences in faecal bacterial compositions in UC and IBS patients compared to healthy controls, and to identify individual bacterial species that contribute to these differences.</p> <p>Methods</p> <p>Faecal microbiota of 13 UC patients, 11 IBS patients and 22 healthy volunteers were analysed by PCR-Denaturing Gradient Gel Electrophoresis (DGGE) using universal and Bacteroides specific primers. The data obtained were normalized using in-house developed statistical method and interrogated by multivariate approaches. The differentiated bands were excised and identified by sequencing the V3 region of the 16S rRNA genes.</p> <p>Results</p> <p>Band profiles revealed that number of predominant faecal bacteria were significantly different between UC, IBS and control group (p < 10^-4). By assessing the mean band numbers in UC (37 ± 5) and IBS (39 ± 6), compared to the controls (45 ± 3), a significant decrease in bacterial species is suggested (p = 0.01). There were no significant differences between IBS and UC. Biodiversity of the bacterial species was significantly lower in UC (μ = 2.94, σ = 0.29) and IBS patients (μ = 2.90, σ = 0.38) than controls (μ = 3.25, σ = 0.16; p = 0.01). Moreover, similarity indices revealed greater biological variability of predominant bacteria in UC and IBS compared to the controls (median Dice coefficients 76.1% (IQR 70.9 - 83.1), 73.8% (IQR 67.0 - 77.5) and 82.9% (IQR 79.1 - 86.7) respectively). DNA sequencing of discriminating bands suggest that the presence of <it>Bacteroides vulgatus, B. ovatus, B. uniformis</it>, and <it>Parabacteroides sp</it>. in healthy volunteers distinguishes them from IBS and UC patients. DGGE profiles of Bacteroides species revealed a decrease of Bacteroides community in UC relative to IBS and controls.</p> <p>Conclusion</p> <p>Molecular profiling of faecal bacteria revealed abnormalities of intestinal microbiota in UC and IBS patients, while different patterns of Bacteroides species loss in particular, were associated with UC and IBS.</p