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Search Results: 1 - 10 of 1647 matches for " Manfred Poniatowski "
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Improving the residual resistivity of pure gold
Manfred Poniatowski,Axel Wirths
Gold Bulletin , 1977, DOI: 10.1007/BF03215441
Abstract: The achievement of exceptionally high purity in gold necessitates extreme care not only in refining but also in subsequent rolling and drawing. This paper describes the precautions adopted to produce extremely high purity gold, as measured by its residual resistivity ratio.
Dispersion hardened gold
M. Poniatowski,M. Clasing
Gold Bulletin , 1972, DOI: 10.1007/BF03215158
Abstract: A limitation to the usefulness of gold in the industrial field is its low hardness and strength, particularly at elevated temperatures. This paper describes the production of a hardened gold by the simultaneous precipitation of gold and of titanium hydroxide, followed by annealing and extrusion. This material possesses excellent cold working properties and considerably higher hardness, tensile strength and creep strength than pure gold at higher temperatures.
Education, Innovation and Growth in Quality-Ladder Models of North-North Trade  [PDF]
Manfred Stadler
Modern Economy (ME) , 2015, DOI: 10.4236/me.2015.610107
Abstract: This paper extends and surveys some basic quality-ladder models of education, innovation and trade in order to explain the dynamics of technological change and aggregate growth in developed countries. We analyze how the stochastic processes of innovation and export adaptation are affected by asymmetric factor endowments, transport costs, and barriers to entry in foreign markets. We show that the country-specific innovation rates are permanently increasing in the effectiveness of education and the countries’ relative endowment with labor. Trade liberalization leads to a temporary increase in the innovation rates but to a permanent increase in the rates of export adaptation.
Quantum Statistics of Random Walks  [PDF]
Manfred Harringer
Journal of Modern Physics (JMP) , 2018, DOI: 10.4236/jmp.2018.97089
Abstract: The paper dealt with quantum canonical ensembles by random walks, where state transitions are triggered by the connections between labels, not by elements, which are transferred. The balance conditions of such walks lead to emission rates of the labels. The labels with emission rates definitely lower than 1 are like modes. For labels with emission rates very close to 1, the quantum numbers are concentrated around a mean value. As an application I consider the role of the zero label in a quantum gas in equilibrium.
Validation study of a computer-based open surgical trainer: SimPraxis® simulation platform
Tran LN,Gupta P,Poniatowski LH,Alanee S
Advances in Medical Education and Practice , 2013,
Abstract: Linh N Tran,1 Priyanka Gupta,2 Lauren H Poniatowski,2 Shaheen Alanee,3 Marc A Dall’Era,4 Robert M Sweet21Department of Internal Medicine, Loma Linda University, Loma Linda, CA, 2Department of Urology, University of Minnesota, Minneapolis, MN, 3Urology Service, Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY, 4Department of Urology, University of California, Davis, CA, USABackground: Technological advances have dramatically changed medical education, particularly in the era of work-hour restrictions, which increasingly highlights a need for novel methods to teach surgical skills. The purpose of this study was to evaluate the validity of a novel, computer-based, interactive, cognitive simulator for training surgeons to perform pelvic lymph node dissection (PLND).Methods: Eight prostate cancer experts evaluated the content of the simulator. Contextual aspects of the simulator were rated on a five-point Likert scale. The experts and nine first-year residents completed a simulated PLND. Time and deviations were logged, and the results were compared between experts and novices using the Mann–Whitney test.Results: Before training, 88% of the experts felt that a validated simulator would be useful for PLND training. After testing, 100% of the experts felt that it would be more useful than standard video training. Eighty-eight percent stated that they would like to see the simulator in the curriculum of residency programs and 56% thought it would be useful for accreditation purposes. The experts felt that the simulator aided in overall understanding, training indications, concepts and steps of the procedure, training how to use an assistant, and enhanced the knowledge of anatomy. Median performance times taken by experts and interns to complete a PLND procedure on the simulator were 12.62 and 23.97 minutes, respectively. Median deviation from the incorporated procedure pathway for experts was 24.5 and was 89 for novices.Conclusion: We describe an interactive, computer-based simulator designed to assist in mastery of the cognitive steps of an open surgical procedure. This platform is intuitive and flexible, and could be applied to any stepwise medical procedure. Overall, experts outperformed novices in their performance on the trainer. Experts agreed that the content was acceptable, accurate, and representative.Keywords: simulation, surgical education, training, simulator, video
Anharmonic coefficients in high symmetry directions for the diamond structure
J.L. Escamilla-Reyez,E. Haro-Poniatowski
Revista mexicana de física , 2005,
Abstract: In this work, the cubic anharmonic coefficients are computed analytically in high symmetry directions considering central potential interactions up to fifth nearest neighbors for crystals with the diamond structure. It is found that certain channels of decay are forbidden. Furthermore particular relations between the different polarizations of the optical phonon for the cubic anharmonic coefficients are presented. Using these results, the validity of the so-called Peierls approximation is discussed.
Scaling of the optical phonon frequency in diamond-like elements and III-V group semiconductor compounds
J.L. Escamilla Reyes,E. Haro Poniatowski
Revista mexicana de física , 2004,
Abstract: En este artículo, estudiamos la homología en las propiedades vibracionales de los sólidos con estructuras tipo diamante y zincblenda. Por medio de la frecuencia adimensional de Tolpygo, escalamos las curvas de dispersión de fonones tanto para elementos con estructura de diamante, así como para algunos compuestos semiconductores de los grupos III-V; además, a partir de las frecuencias de los fonones en elementos con estructura de diamante, obtenemos las frecuencias del fonón óptico en compuestos AB. Considerando la sencillez de los cálculos empleados, la concordancia entre los resultados teóricos y los valores experimentales es notable.
The Relevance of Web Mapping Infrastructures in a Web Portal for Desktop and Mobile Devices: A Case Study  [PDF]
Kai Behncke, Manfred Ehlers
Journal of Geographic Information System (JGIS) , 2012, DOI: 10.4236/jgis.2012.46056
Abstract: There exists a lack of detailed empirical studies to assess the relevance of WebMapping applications. Despite this fact, it is quite common to note that importance and influence of WebMapping applications have increased over the last years. This paper presents the result of an empirical study to analyze the importance of a Desktop-WebMapping application for a gastronomic web 2.0 portal for the city of Osnabrück. An exploratory focus is to evaluate how often geospatial information (in a broader information context) from this web portal is used and how important the WebMapping applications are for the users of the web portal. Furthermore, it is evaluated which WebMapping functions (e.g. routing, queries, printing) are of relevance to the users and what the order of importance is for the provided functions. To-date, just a few mobile WebMapping applications for handheld devices exist. Consequently, for OsnaGo we developed a mobile WebMapping component that can be used with mobile phones, PDAs and other handheld devices to access the web portal (http://www.osnago-mobil.de). Development and user based evaluation is presented in this paper.

On the Evolution of Approaches to the Space-Time Symmetry  [PDF]
Mikhail Petelin, Manfred Thumm
Natural Science (NS) , 2018, DOI: 10.4236/ns.2018.103008
Abstract: The general space-time composition was analyzed starting in ancient times. During the previous three millenniums, to explain elementary physical phenomena, the world was twice admitted to be immersed into an “aether”. Presently the “aether” is assumed to be asymptotically close to the vacuum. This approximation is included in the foundation of the special theory of relativity.
Gauge Coupling Unification in Left-Right Symmetric Models
Manfred Lindner,Manfred Weiser
Physics , 1996, DOI: 10.1016/0370-2693(96)00775-7
Abstract: We explore possibilities of gauge coupling unification in left--right symmetric models with non--minimal particle content. In addition to unification we require the absence of anomalies and sufficient proton lifetime. Numerous previously unknown solutions are presented where unification occurs within the latest experimental errors. Solutions exist where the scale of left--right symmetry breaking can be as low as ${\cal O}(TeV)$ or the scale $M_R$ as high as the Planck scale.
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