22 research outputs found

    Mathematical modeling of the dynamics of a shovel with flexible coupling

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    To study the possible ergonomic and energetic advantages on the use of a shovel with a flexible coupling, a dynamic analysis of the motion of the blade together with the lifted raw material was conducted. By this dynamic analysis, ordinary differential equations were set up. Therefore the closed-form solutions were found to obtain useful equations for simulation. The application of mathematical modeling both to the blade with elastic coupling and to the traditional one, allowed to quantify the zeroing of the operator effort in the second half of the blade lifting. However, in the first part of the lifting an effort increase occurs, but in this first phase the operator can take advantage from the support on the thigh, thus lightening the load on the spine

    Global patient outcomes after elective surgery: prospective cohort study in 27 low-, middle- and high-income countries.

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    BACKGROUND: As global initiatives increase patient access to surgical treatments, there remains a need to understand the adverse effects of surgery and define appropriate levels of perioperative care. METHODS: We designed a prospective international 7-day cohort study of outcomes following elective adult inpatient surgery in 27 countries. The primary outcome was in-hospital complications. Secondary outcomes were death following a complication (failure to rescue) and death in hospital. Process measures were admission to critical care immediately after surgery or to treat a complication and duration of hospital stay. A single definition of critical care was used for all countries. RESULTS: A total of 474 hospitals in 19 high-, 7 middle- and 1 low-income country were included in the primary analysis. Data included 44 814 patients with a median hospital stay of 4 (range 2-7) days. A total of 7508 patients (16.8%) developed one or more postoperative complication and 207 died (0.5%). The overall mortality among patients who developed complications was 2.8%. Mortality following complications ranged from 2.4% for pulmonary embolism to 43.9% for cardiac arrest. A total of 4360 (9.7%) patients were admitted to a critical care unit as routine immediately after surgery, of whom 2198 (50.4%) developed a complication, with 105 (2.4%) deaths. A total of 1233 patients (16.4%) were admitted to a critical care unit to treat complications, with 119 (9.7%) deaths. Despite lower baseline risk, outcomes were similar in low- and middle-income compared with high-income countries. CONCLUSIONS: Poor patient outcomes are common after inpatient surgery. Global initiatives to increase access to surgical treatments should also address the need for safe perioperative care. STUDY REGISTRATION: ISRCTN5181700

    Development of a statistical method for determining the required sample size to assure the air tightness quality of buildings

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    Abweichender Titel laut Übersetzung der Verfasserin/des VerfassersZsfassung in engl. SpracheDie vorliegende Diplomarbeit beschäftigt sich mit der Verteilung der Luftwechselzahl einer Wohnsiedlung mit ähnlichen oder identischen Gebäuden/Wohneinheiten. Die wesentliche Fragestellung ist dabei die Ermittlung der nötigen Anzahl an Luftdichtheitsmessungen aus der Grundgesamtheit, um nach der Wahrscheinlichkeitstheorie die Einhaltung gesetzlich vorgegebener Grenzwerte der Luftwechselzahl mit einer gewissen Sicherheit zu gewährleisten. Die Ergebnisse einer durchgeführten Messreihe zur Luftdichtheit der Gebäude einer Kleingartenwohnhausanlage, sowie Referenzmessdaten weiterer Wohn- und Reihenhaussiedlung dienen als Grundlage zur Lösung der Fragestellung.Unter Annahme lognormalverteilter, sowie alternativ gammaverteilter Luftwechselzahlen, kann simulativ die erforderliche Stichprobengröße ermittelt werden. Grundlage des Berechnungsmodells ist dabei ein Bayes`scher Ansatz unter Benützung der suffizienten Statistiken der Stichprobe. Durch errechnen statistischer Kennzahlen aus einer gemessenen Stichprobe und mit Hilfe der aus der Simulation hervorgehenden Diagramme kann die Fragestellung und somit die erforderliche Stichprobengröße ermittelt werden. Vorausblickend erlaubt das Berechnunsmodell auch die Implementierung in computerunterstützte Verfahrensweisen, wodurch sich die Wahrscheinlichkeitsberechnung nicht nur genauer, sondern auch anwendungsfreundlicher gestaltet.The present thesis deals with the distribution of air exchange rate of a residential area with similar or identical buildings/units.The main research question is to determine the required number of air tightness measurements of the population to ensure compliance with legally prescribed limits of air exchange rate on the probability theory. The results of a series of air tightness measurements in houses of a small garden apartment complex, as well as reference measurement data of other residential and row houses provide a basis for solving the problem. Assuming lognormal-distributed, and alternatively gamma distributed air change rates the required sample sizecan be assessed by simulation. Basis of the calculation model is a Bayesian approach by the use of the sufficient statistics sample properties. Calculated statistical figures from a measured sample and by using the resulting graphs from the simulation the main question and the required sample size can be determined. Presumably, the simulation model also allows an implementation in computer-based procedures. Hereby, the propability calculation will be more accurate, but also more applicationfriendly.11

    Integration of airborne gravimetry data filtering into residual least-squares collocation: example from the 1 cm geoid experiment

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    Low-pass filters are commonly used for the processing of airborne gravity observations. In this paper, for the first time, we include the resulting correlations consistently in the functional and stochastic model of residual least-squares collocation. We demonstrate the necessity of removing high-frequency noise from airborne gravity observations, and derive corresponding parameters for a Gaussian low-pass filter. Thereby, we intend an optimal combination of terrestrial and airborne gravity observations in the mountainous area of Colorado. We validate the combination in the frame of our participation in ‘the 1 cm geoid experiment’. This regional geoid modeling inter-comparison exercise allows the calculation of a reference solution, which is defined as the mean value of 13 independent height anomaly results in this area. Our result performs among the best and with 7.5 mm shows the lowest standard deviation to the reference. From internal validation we furthermore conclude that the input from airborne and terrestrial gravity observations is consistent in large parts of the target area, but not necessarily in the highly mountainous areas. Therefore, the relative weighting between these two data sets turns out to be a main driver for the final result, and is an important factor in explaining the remaining differences between various height anomaly results in this experiment.Technische Universität München (1025

    Integration of airborne gravimetry data filtering into residual least-squares collocation: example from the 1 cm geoid experiment

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    <jats:title>Abstract</jats:title><jats:p>Low-pass filters are commonly used for the processing of airborne gravity observations. In this paper, for the first time, we include the resulting correlations consistently in the functional and stochastic model of residual least-squares collocation. We demonstrate the necessity of removing high-frequency noise from airborne gravity observations, and derive corresponding parameters for a Gaussian low-pass filter. Thereby, we intend an optimal combination of terrestrial and airborne gravity observations in the mountainous area of Colorado. We validate the combination in the frame of our participation in ‘the 1 cm geoid experiment’. This regional geoid modeling inter-comparison exercise allows the calculation of a reference solution, which is defined as the mean value of 13 independent height anomaly results in this area. Our result performs among the best and with 7.5 mm shows the lowest standard deviation to the reference. From internal validation we furthermore conclude that the input from airborne and terrestrial gravity observations is consistent in large parts of the target area, but not necessarily in the highly mountainous areas. Therefore, the relative weighting between these two data sets turns out to be a main driver for the final result, and is an important factor in explaining the remaining differences between various height anomaly results in this experiment.</jats:p&gt

    Rare Case of a Dislocated Spleen in a Patient With B-Cell Lymphoma

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