31,272 research outputs found

    Asymptotic Methods for Asset Market Equilibrium Analysis

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    General equilibrium analysis is difficult when asset markets are incomplete. We make the simplifying assumption that uncertainty is small and use bifurcation methods to compute Taylor series approximations for asset demand and asset market equilibrium. A computer must be used to derive these approximations since they involve large amounts of algebraic manipulation. To illustrate this method, we apply it to analyzing the allocative, price, and welfare effects of introducing a new derivative security. We find that the introduction of any derivative will raise the value of the risky asset relative to bonds.

    Methods of Improving the Student Teaching Experience at the Elementary and Junior High School Levels as Identified by Cooperating Teachers, Student Teachers and First Year Teachers

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    The purpose of this field experience was to identify how the student teaching experience could be improved based upon recommendations by cooperating teachers, first year teachers and student teachers who completed a questionnaire. Each group was asked its opinions of the current status of the student teaching experience and how the process could be improved. Cooperating teachers provided information relative to the special types of activities they conducted to better prepare student teachers for the profession. Current student teachers were asked to determine the teaching skills with which they needed the most assistance. First year teachers provided information that compared the student teaching experience to the reality of the first year on the job and what teaching skills needed to insure educational survival in the first year of teaching. This survey was conducted in conjunction with the Office of Clinical Experiences at Eastern Illinois University, Charleston, Illinois under the direction of Dr. Francis Summers. Findings from this study include (a) feelings by all groups that a semester of student teaching was ample time to effectively conduct the experience, (b) a listing of possible activities that could be used to effectively orient the student teacher to teaching profession, (c) while the working relationships between student and cooperating teachers were good, stress factors revolved around the student teachers\u27 inability to effectively discipline the classes, (d) the video camera is an effective but little utilized tool for self-evaluation during student teaching, (e) feedback from cooperating teachers to student teachers has been continuous, productive and positive, (f) teacher preparatory college classes are preparing students for the teaching profession except for the subject of disciplining students and (g) the role of the university coordinator includes the functions of an evaluator and counselor for the student teacher along with being a liaison/administrator for the teacher education program and periodically a trouble shooter when problems arise between the student and cooperating teacher. Major recommendations were (a) for colleges of education in universities across the nation to devote at least one methods class to prepare student teachers for the rigors of disciplining students and (b) that the position of university coordinator must include the role of identifying and weeding out cooperating teachers who do not provide a high quality student teaching experience

    Dynamical Casimir-Polder force between an excited atom and a conducting wall

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    We consider the dynamical atom-surface Casimir-Polder force in the nonequilibrium configuration of an atom near a perfectly conducting wall, initially prepared in an excited state with the field in its vacuum state. We evaluate the time-dependent Casimir-Polder force on the atom and find that it shows an oscillatory behavior from attractive to repulsive both in time and in space. We also investigate the asymptotic behavior in time of the dynamical force and of related local field quantities, showing that the static value of the force, as obtained by a time-independent approach, is recovered for times much longer than the time scale of the atomic self-dressing but shorter than the atomic decay time. We then discuss the evolution of global quantities such as atomic and field energies and their asymptotic behavior. We also compare our results for the dynamical force on the excited atom with analogous results recently obtained for an initially bare ground-state atom. We show that new relevant features are obtained in the case of an initially excited atom, for example, much larger values of the dynamical force with respect to the static one, allowing for an easier way to single out and observe the dynamical Casimir-Polder effect

    Use of FBG optical sensors for structural health monitoring: Practical application

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    This paper describes the development of FBG Optical sensors for their practical application on structural health monitoring. The sensors were installed on the Tsing Ma Bridge for a trial run. The results using FBG sensors were in excellent agreement with those acquired by the bridge WASHMS

    Recent advances and potential future applications of MALDI-TOF mass spectrometry for identification of helminths

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    Helminth infections caused by nematodes, trematodes, and cestodes are major neglected tropical diseases and of great medical and veterinary relevance. At present, diagnosis of helminthic diseases is mainly based on microscopic observation of different parasite stages, but microscopy is associated with limited diagnostic accuracy. Against this background, recent studies described matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry as a potential, innovative tool for helminth identification and differentiation. MALDI-TOF mass spectrometry is based on the analysis of spectra profiles generated from protein extracts of a given pathogen. It requires an available spectra database containing reference spectra, also called main spectra profiles (MSPs), which are generated from well characterized specimens. At present, however, there are no commercially available databases for helminth identification using this approach. In this narrative review, we summarize recent developments and published studies between January 2019 and September 2022 that report on the use of MALDI-TOF mass spectrometry for helminths. Current challenges and future research needs are identified and briefly discussed

    Laparoscopic resection of gastric wall tumor

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    Avoid Oversimplifications in Machine Learning: Going beyond the Class-Prediction Accuracy.

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    Class-prediction accuracy provides a quick but superficial way of determining classifier performance. It does not inform on the reproducibility of the findings or whether the selected or constructed features used are meaningful and specific. Furthermore, the class-prediction accuracy oversummarizes and does not inform on how training and learning have been accomplished: two classifiers providing the same performance in one validation can disagree on many future validations. It does not provide explainability in its decision-making process and is not objective, as its value is also affected by class proportions in the validation set. Despite these issues, this does not mean we should omit the class-prediction accuracy. Instead, it needs to be enriched with accompanying evidence and tests that supplement and contextualize the reported accuracy. This additional evidence serves as augmentations and can help us perform machine learning better while avoiding naive reliance on oversimplified metrics
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