139 research outputs found
Application of acute maximal exercise to protect orthostatic tolerance after simulated microgravity
No full text Pages R837–R847: K. A. Engelke, D. F. Doerr, and V. A. Convertino. “Application of acute maximal exercise to protect orthostatic tolerance after simulated microgravity.” On p. 837, the author line of the article and abstract and the affiliation line should read as follows: KEITH A. ENGELKE, DONALD F. DOERR,CRAIG G. CRANDALL, AND VICTOR A. CONVERTINO Department of Physiology, University of Florida, Gainesville, Florida 32610; National Aeronautics and Space Administration-Kennedy Space Center, Cape Canaveral, Florida 32899;Department of Physiology, University of North Texas Health Science Center, Ft. Worth, Texas 76107; and Physiology Research Branch, Clinical Science Division, Brooks Air Force Base, Texas 78235 </jats:p
Application of acute maximal exercise to protect orthostatic tolerance after simulated microgravity
No full text Pages R837–R847: K. A. Engelke, D. F. Doerr, and V. A. Convertino. “Application of acute maximal exercise to protect orthostatic tolerance after simulated microgravity.” On p. 837, the author line of the article and abstract and the affiliation line should read as follows: KEITH A. ENGELKE, DONALD F. DOERR, CRAIG G. CRANDALL, AND VICTOR A. CONVERTINO Department of Physiology, University of Florida, Gainesville, Florida 32610; National Aeronautics and Space Administration-Kennedy Space Center, Cape Canaveral, Florida 32899; Department of Physiology, University of North Texas Health Science Center, Ft. Worth, Texas 76107; and Physiology Research Branch, Clinical Science Division, Brooks Air Force Base, Texas 78235 </jats:p
Does Forest Continuity Enhance the Resilience of Trees to Environmental Change?
No full textThere is ample evidence that continuously existing forests and afforestations on previously agricultural land differ with regard to ecosystem functions and services such as carbon sequestration, nutrient cycling and biodiversity. However, no studies have so far been conducted on possible long-term (>100 years) impacts on tree growth caused by differences in the ecological continuity of forest stands. In the present study we analysed the variation in tree-ring width of sessile oak (Quercus petraea (Matt.) Liebl.) trees (mean age 115-136 years) due to different land-use histories (continuously existing forests, afforestations both on arable land and on heathland). We also analysed the relation of growth patterns to soil nutrient stores and to climatic parameters (temperature, precipitation). Tree rings formed between 1896 and 2005 were widest in trees afforested on arable land. This can be attributed to higher nitrogen and phosphorous availability and indicates that former fertilisation may continue to affect the nutritional status of forest soils for more than one century after those activities have ceased. Moreover, these trees responded more strongly to environmental changes - as shown by a higher mean sensitivity of the tree-ring widths - than trees of continuously existing forests. However, the impact of climatic parameters on the variability in tree-ring width was generally small, but trees on former arable land showed the highest susceptibility to annually changing climatic conditions. We assume that incompletely developed humus horizons as well as differences in the edaphon are responsible for the more sensitive response of oak trees of recent forests (former arable land and former heathland) to variation in environmental conditions. We conclude that forests characterised by a long ecological continuity may be better adapted to global change than recent forest ecosystems
Design Recommendations for Augmented Reality based Training of Maintenance Skills
No full textTraining for service technicians inmaintenance tasks is a classical application field of Augmented Reality explored by different research groups. Mostly technical aspects (tracking, visualization etc.) have been in focus of this research field. In this chapter we present results of interdisciplinary research based on the fusion of cognitive science, psychology and computer science. We focus on analyzing the improvement of Augmented Reality based training of skills which are relevant for maintenance and assembly tasks. The skills considered in this work comprise sensorimotor skills as well as cognitive skills. Different experiments have been conducted in order to find recommendations for the design of Augmented Reality training systems which overcome problems of existing approaches. The suggestions concern the fields of content visualization and multimodal feedback
Bestimmung von Matching-Wahrscheinlichkeiten für Histogrammed-Intensity-Patches
No full textThis work presents a way to estimate the matching probabilities for histogrammed intensity patches [41] by approximating the robustness and distinctiveness of a feature with beta distributions. We propose a simplified analytical approach to calculate the distinctiveness and show that it produces at least as good results as a specifically trained neural network. The matching probability correlates stronger with the inlier ratio than the dissimilarity score does. We then evaluate a basic tracking by detection pipeline where no longer the closest but the most probable match is chosen. Our tests show, that this improves the average performance of the system in terms of tracking rate.Diese Arbeit stellt einen Weg vor, um die Matching-Wahrscheinlichkeiten von Histogrammed-Intensity- Patches [41] zu berechnen in dem die Robustheit und Unterscheidungskraft der Merkmale mit Betaverteilungen angenähert werden. Wir schlagen weiterhin einen vereinfachten analytischen Ansatz zur Berechnung der Unterscheidungskraft vor und zeigen, dass dieses zumindest so guten Ergebnisses wie ein speziell für die Vorhersage der ursprünglichen Unterscheidungskraft trainiertes Neuronales Netzwerk erzielt. Die Matching Wahrscheinlichkeit korreliert stärker mit dem Anteil an Ausreißern als es die Dissimilarity-Score tut. Schließlich evaluieren wir ein Tracking-by-Detection-Verfahren, bei dem nicht mehr die nächste Übereinstimmung sondern die wahrscheinlichste gewählt wird. Unsere Testergebnisse zeigen, dass das durchschnittliche Abschneiden dieses Systems in Bezug auf Tracking-Rate verbessert wurde
Sticky subjects, sticky objects: The substance of African Christian healing
No full textThroughout history and across social and cultural contexts, most systems of belief-whether religious or secular-have ascribed wisdom to those who see reality as that which transcends the merely material. Yet, as the studies collected here show, the immaterial is not easily separated from the material. Humans are defined, to an extraordinary degree, by their expressions of immaterial ideals through material forms. The essays in Materiality explore varied manifestations of materiality from ancient times to the present. In assessing the fundamental role of materiality in shaping humanity, they signal the need to de-center the social within social anthropology in order to make room for the material.Considering topics as seemingly diverse as theology, technology, finance, and art, the contributors-most of whom are anthropologists-examine the many different ways in which materiality has been understood and the consequences of these differences. Their case-studies show that the latest forms of financial trading instruments can be compared with the oldest ideals of ancient Egypt, that the promise of software can be compared with an age-old desire for an unmediated relationship to divinity. Whether focusing on the theology of Islamic banking; Australian Aboriginal art; derivatives trading in Japan; or textiles which respond directly to their environment, each essay adds depth and nuance to the project that Materiality advances: a profound acknowledgment and rethinking of one of the most basic properties of being human.Contributors. Matthew Engelke, Webb Keane, Susanne Küchler, Bill Maurer, Lynn Meskell, Daniel Miller, Hirokazu Miyazaki, Fred Myers, Christopher Pinney, Michael Rowlands, Nigel ThriftDaniel Miller is Professor of Anthropology at University College London. He is the author of many books including The Sari (with Mukulika Banerjee); Capitalism: An Ethnographic Approach; A Theory of Shopping; and The Internet: An Ethnographic Approach (with Don Slater). He is the editor, most recently, of Home Possessions: Material Culture behind Closed Doors and Car Cultures
Quantitative Ultrasound of Cortical Bone in the Femoral Neck Predicts Femur Strength: Results of a Pilot Study
No full textArticle first published online: 15 JAN 2013 Pour consulter la version éditeur DOI: 10.1002/jbmr.1742A significant risk of femoral neck (FN) fracture exists for men and women with an areal bone mineral density (aBMD) higher than the osteoporotic range, as measured with dual-energy X-ray absorptiometry (DXA). Separately measuring the cortical and trabecular FN compartments and combining the results would likely be a critical aspect of enhancing the diagnostic capabilities of a new technique. Because the cortical shell determines a large part of FN strength a novel quantitative ultrasound (QUS) technique that probes the FN cortical compartment was implemented, aimed at testing the sensitivity of the method to variations of FN cortical properties and FN strength. Nine femurs (women, mean age 83 years) were subjected to QUS to measure the through transmission time-of-flight (TOF) at the FN and mechanical tests to assess strength. Quantitative computed tomography (QCT) scans were performed to enable analysis of the dependence of TOF on bone parameters. DXA was also performed for reference. An ultrasound wave propagating circumferentially in the cortical shell, which TOF was not influenced by the properties of the trabecular compartment Q3, was measured in all specimens. Averaged TOF for nine FN measurement positions/orientations was significantly correlated to strength (R² = 0.79) and FN cortical QCT variables: total BMD (R² = 0.54); regional BMD in the inferoanterior (R² = 0.90) and superoanterior (R² = 0.57) quadrants; and moment of inertia (R² = 0.71). The results of this study demonstrate that QUS can perform a targeted measurement of the FN cortical compartment. Because the method involves mechanical guided waves, the QUS variable is related to the geometric and material properties of the cortical shell (cortical thickness, tissue elasticity, and porosity). This work opens the way to a multimodal QUS assessment of the proximal femur, combining our approach targeting the cortical shell with the existing modality sensitive to the trabecular compartment. In vivo feasibility of our approach has to be confirmed with experimental data in patients
Intuitive Interaction with VR Applications Using Video-based Gesture Recognition
No full textS.37-40This paper describes the implementation od a deviceless interaction 'device' using hand gesture recognition within a calibrated stereo system. Video-based interaction is one of the most intuitive kinds of Human Computer Interaction with Virtual Reality applications due to the fact that users are not wired to a computer. If interaction with three-dimensional environments is considered, pointing, grabbing and releasing are the most intuitive gestures used by humans. This paper describes a video-based gesture recognition that observes the user in front of a large displaying screen, indentifying three different hand gestures in real time using 2D feature classification and determines 3D information like the 3D position of the user's hand or the pointing direction if performed. Different scenario applications like a virtual chess game against the computer or an industrial scenario have been deployed and tested
Constrained Multi-Aircraft Maintenance Scheduling Using Component Prognostics
No full textIn recent years, airlines have increasingly developed the ability to monitor the condition of aircraft components by means of sensors. In turn, aircraft maintenance aims to use this sensor data to predict component failures. However, the challenge remains to make use of these prognostics to generate appropriate maintenance schedules. In this paper, we develop a Monte-Carlo tree search to schedule maintenance tasks based on component prognostics and available maintenance slots. This approach is used to create a maintenance policy for multiple aircraft which specifies which aircraft are allocated for maintenance and on which days. The results show that the scheduling of the maintenance tasks is robust and able to accommodate the maintenance scheduling of smaller airline fleet sizes. Overall, our results support the integration of aircraft component prognostics in aircraft maintenance scheduling.Aerospace Engineerin
Discontinuity and the discourse of conversion
No full textThis paper focuses on the conversion narrative of a man in the Johane Masowe weChishanu Church, an apostolic church in Zimbabwe. Taking up recent discussions within anthropology on Pentecostal and charismatic churches, the author shows how apostolics talk about conversion as a distinct break with 'African custom'. It is argued that anthropologists of religion need to take such narratives of discontinuity seriously because they allow us to understand better the dynamics of religious change
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