An improved bound for a fundamental constant associated with a P-matrix

AbstractLet M be an n-by-n P-matrix. We determine the optimal lower bound for the quantity α(M) ≡ min {maxi xi(Mx)i : x ϵ Rn, ‖x‖∞ = 1} based on the real eigenvalues of the principal submatrices of M and the maximum of the absolute values of the off-diagonal entries of M. This bound is positive whenever M is a P-matrix

Application of the regression of offspring on mid-parent method to detect associations between single-nucleotide polymorphisms and the beta 2 electroencephalogram phenotype in the COGA data

The beta 2 electroencephalogram (EEG) phenotype is used as a quantitative measure related to alcoholism, and evidence of linkage and association has previously been reported in the Collaborative Study on the Genetics of Alcoholism data. In this study, associations between the beta 2 EEG phenotype and single nucleotide polymorphisms from whole-genome Illumina and Affymetrix panels were investigated with the regression of offspring on mid-parent method to identify significant genetic effects and to estimate their heritability. Separate regressions on father and mother were performed to identify parent-specific effects. Estimates of the heritability of the beta 2 EEG phenotype were 0.68 ± 0.12 and 0.52 ± 0.07 based on father-offspring and mother-offspring pairs, respectively. Significant associations at the 0.0005 level, some of which were parent-specific, were found on chromosomes 1, 2, 5, 6, 7, 8, 11, 12, 15, 16, 17, 18, and 19 with heritability attributable to each SNP ranging from 0.01 to 8%

Adaptive calculation of pass sequences for open die forging

Open-die forging is one of the oldest forming processes in history, which has been continuously developed through technical innovations. The rapid development in the fields of measurement and control technology and the computing capacity of IT systems in recent decades offer the opportunity to take open-die forging to a higher level. In order to establish a fully autonomous forging process, a forging cell is being set up at the Institute of Metal Forming at TU Bergakademie Freiberg. It consists of two forging presses, a furnace and a KR 360 L280-2 robot arm from KUKA as a manipulator with a load capacity of up to 280 kg. A 3D scanning system allows to capture the workpiece geometry between individual pass sequences or even single press strokes. Additionally, the scanning system is equipped with three thermal imaging cameras, which record the surface temperature during a scan. A central computer controls all individual components of the forging cell

Impact of non-cardiovascular disease burden on thirty-day hospital readmission in heart failure patients

Background: Little is known about the impact of non-cardiovascular disease (CVD) burden on 30- -day readmission in heart failure (HF) patients. The aim of the study was to assess the role of non-CVD burden on 30-day readmission in HF patients. \ Methods: We analyzed the effect of non-CVD burden by frequency of ICD-9 code categories on readmis­sions of patients discharged with a primary diagnosis of HF. We first modeled the probability of readmis­sion within 30 days as a function of demographic and clinical covariates in a randomly selected training dataset of the total cohort. Variable selection was carried out using a bootstrap LASSO procedure with 1000 bootstrap samples, the final model was tested on a validation dataset. Adjusted odds ratios and confidence intervals were reported in the validation dataset. Results: There were a total of 6228 HF hospitalizations, 1523 (24%) with readmission within 30 days of discharge. The strongest predictor for 30-day readmissions was any hospital admission in the prior year (p < 0.001). Cardiovascular risk factors did not enter the final model. However, digestive system diseases increased the risk for readmission by 17% for each diagnosis (p = 0.046), while respiratory diseases and genitourinary diseases showed a trend toward a higher risk of readmission (p = 0.07 and p = 0.09, respectively). Non-CVDs out-competed cardiovascular covariates previously reported to predict readmission. Conclusions: In patients with HF hospitalization, prior admissions predicted 30-day readmission. Diseases of the digestive system also increase 30-day readmission rates. Assessment of non-CVD burden in HF patients could serve as an important risk marker for 30-day readmissions

Landscape-related ground ice variability on the Yukon coastal plain inferred from computed tomography and remote sensing

Warming in the Arctic causes strong environmental changes with degradation of permafrost (permanently frozen ground). Active layer deepening (gradual thaw) and permafrost erosion (abrupt thaw) results in the mobilization and lateral transport of organic carbon, altering current carbon cycling in the Arctic. Ground ice content is a crucial factor limiting our understanding and ability to determine the rates and dynamics of permafrost thaw and its impact on potential thaw subsidence rates, changes in lateral hydrological pathways and its driving mechanisms on a landscape scale. In this study we investigate ground ice content and its characteristics across the most dominant landscape units of the Yukon coastal plain (Canadian Arctic), using two spatially and technically contrasting approaches. In our bottom-up approach, twelve permafrost cores were collected from moraine, lacustrine, fluvial and glaciofluvial deposits using a SIPRE corer (mean drilling depth of 2 m) in spring of 2019. Ground ice and sediment contents within polygon centers were analyzed and classified using computed tomography and image recognition software (k-means). Our top-down approach quantified ice-wedge volumes from remote sensing imagery tracing the circumference of polygon troughs over the same area. Preliminary results - extrapolated to the entire coastal plain - show that the ground-ice content in polygon centers vary significantly from massive ice in the polygon troughs (wedge-ice). Total ice volume was estimated around 80.2 vol.-%, of which 68.2 ± 18.1 vol.-% was attributed to ground ice in polygon centers, and 12 ± 3.1 vol.-% of the landscape is massive ice in wedge-ice along polygon troughs. Additionally, differences among and between landscape units are also substantial, with highest ice volume contents in moraines landscapes, where polygon centers contain 58.8 vol.-% ground ice and wedge-ice volume is 16.2 vol.-%), while the lowest ice contents are found in glacio-fluvial deposits (22.1 vol.-% resp. 9.1 vol.-%). Our results reveal a higher average and a larger variability in ground ice contents than previously found, suggesting a need of both ground-based measurements and remote sensing imagery to further our understanding of the future landscape subsidence, but also to avoid a likely under- or overestimation associated with the chosen approach. We conclude that due to the high ground ice contents on the Yukon coastal plain, substantial changes of the permafrost landscape will occur under current warming trends. These will include subsidence, abrupt erosion, changes in hydrology and organic carbon mobilization, degradation and export processes, which will differ between landscape units

Adaptive Stichplanung im Freiformschmieden

Das Freiformschmieden ist eines der ältesten Umformverfahren in der Geschichte, das kontinuierlich durch technische Innovationen weiterentwickelt wurde. Die rasante Entwicklung in den Bereichen der Mess- und Regelungstechnik sowie der Rechenkapazität von IT-Systemen in den letzten Jahrzehnten bietet die Möglichkeit, das Freiform-schmieden auf seine nächste Entwicklungsebene zu heben. Um einen vollautonomen Schmiedeprozess zu etablieren, wird am Institut für Metallformung der TU Bergakademie Freiberg eine Schmiedezelle eingerichtet. Diese Verfügt über zwei Schmiedepressen, einen Ofen und einen Roboterarm vom Typ KR 360 L280-2 der Firma KUKA mit einer Traglast von bis zu 280 kg als Manipulator. Mithilfe eines 3D-Scansystems ist es möglich die Werkstückgeometrie zwischen einzelnen Stichen oder gar Pressenhüben zu erfassen. Weiterhin verfügt das Scansystem über drei Wärmebildkameras, welche während eines Scans die Oberflächentemperatur erfassen. Die einzelnen Komponenten der Schmiedezelle werden über einen Zentralrechner gesteuert

Comparison of year-of-exam- and age-matched estimates of heritability in the Framingham Heart Study data

Several different approaches can be used to examine generational and temporal trends in family studies. The measurement of offspring and parents can be made over a short period of time with parents and offspring having quite different ages, or measurements can be made at the same ages but with decades between parent and offspring measures. A third approach, used in the Framingham Heart Study, has repeated examinations across a broad range of age and time, and provides a unique opportunity to compare these approaches. Parents and offspring were matched both on (year of exam) and on age. Heritability estimates for systolic blood pressure, body mass index, height, weight, cholesterol, and glucose were obtained by regressing offspring on midparent values with and without adjustment for age. Higher estimates of heritability were obtained for age-matched than for year-of-exam-matched data for all traits considered. For most traits, estimates of the heritability of the change over time (slope) of the trait were near zero. These results suggest that the optimal design to identify genetic effects in traits with large age-related effects may be to measure parents and offspring at similar ages and not to rely on age-adjustment or longitudinal measures to account for these temporal effects