The limit from the Schrödinger-Poisson to the Vlasov-Poisson equations with general data in one dimension

2002 ◽  
Vol 55 (5) ◽  
pp. 582-632 ◽  
Author(s):  
Ping Zhang ◽  
Yuxi Zheng ◽  
Norbert J. Mauser
Keyword(s):  
One Dimension ◽  
Poisson Equations ◽  
General Data

The a Posteriori Error Estimates for Chebyshev-Galerkin Spectral Methods in One Dimension

2015 ◽  
Vol 7 (2) ◽  
pp. 145-157 ◽  
Author(s):  
Jianwei Zhou
Keyword(s):  
A Priori ◽  
A Posteriori Error Estimates ◽  
Posteriori Error ◽  
One Dimension ◽  
A Posteriori ◽  
Error Estimators ◽  
Poisson Equations ◽  
Spectral Approximations ◽  
Fourth Order Equations ◽  
Error Indicators

AbstractIn this paper, the Chebyshev-Galerkin spectral approximations are employed to investigate Poisson equations and the fourth order equations in one dimension. Meanwhile, p-version finite element methods with Chebyshev polynomials are utilized to solve Poisson equations. The efficient and reliable a posteriori error estimators are given for different models. Furthermore, the a priori error estimators are derived independently. Some numerical experiments are performed to verify the theoretical analysis for the a posteriori error indicators and a priori error estimations.

scholarly journals Shock-like solutions of the electrostatic Vlasov equation

1969 ◽  
Vol 3 (1) ◽  
pp. 1-11 ◽  
Author(s):  
David Montgomery ◽  
Glenn Joyce
Keyword(s):  
Electrostatic Potential ◽  
Vlasov Equation ◽  
One Dimension ◽  
Zero Temperature ◽  
Trapped Electrons ◽  
Poisson Equations ◽  
Positive Ions ◽  
Upper Limit ◽  
Fluid Equations

It is shown how to construct shock-like time independent solutions of the electrostatic Vlasov and Poisson Equations in one dimension. The positive ions are assumed to be at zero temperature. The electrostatic potential is assumed to increase monotonically through the shock from zero to a constant value. The most important feature of the solution is a population of trapped electrons in the shocked plasma. In contrast to time-independent solutions based upon fluid equations, there is no upper limit on the amplitude of the shock.

The Artist and Androgyny: A Study of Gender Identity in Visual Artists

1988 ◽  
Vol 6 (1) ◽  
pp. 67-78 ◽  
Author(s):  
Catherine T. Harris ◽  
Philip J. Perricone ◽  
Margaret Supplee Smith
Keyword(s):  
Gender Identity ◽  
Visual Arts ◽  
One Dimension ◽  
Visual Artists ◽  
Check List ◽  
The Public ◽  
Adjective Check List ◽  
General Data

While art is an activity that is socially valued, the image of the artist as perceived by the public and expressed in the literature has rarely been studied empirically. The Adjective Check List is used to test one dimension of this issue—June Wayne's hypothesis that the artist is a stereotypical woman, focusing on the artist's view of himself/herself and artists in general. Data were gathered by means of a questionnaire mailed to 1753 artists who had been nominated for the national Awards in Visual Arts during the first five years of the program (1982–86). It was found that artists tend to have self-images which are androgynous in terms of sex stereotyping, while at the same time, they see artists in general as relatively masculine. It was also found that while artists tend to view their colleagues in favorable terms, they view themselves as individual artists significantly more favorably. The implications of these findings for the profession of art are discussed.

Reconstruction of Objects from their Projections Using Orthogonal Functions

1973 ◽  
Vol 31 ◽  
pp. 268-269
Author(s):  
Elrnar Zeitler
Keyword(s):  
Unit Area ◽  
Three Dimensional ◽  
One Dimension ◽  
Spatial Density ◽  
Dimensional Representation ◽  
Orthogonal Functions ◽  
Object A ◽  
Plane Normal ◽  
Dimensional Object ◽  
Spatial Density Distribution

Considering any finite three-dimensional object, a “projection” is here defined as a two-dimensional representation of the object's mass per unit area on a plane normal to a given projection axis, here taken as they-axis. Since the object can be seen as being built from parallel, thin slices, the relation between object structure and its projection can be reduced by one dimension. It is assumed that an electron microscope equipped with a tilting stage records the projectionWhere the object has a spatial density distribution p(r,ϕ) within a limiting radius taken to be unity, and the stage is tilted by an angle 9 with respect to the x-axis of the recording plane.

Quantitative Diameter Measurements of Chromatin and TMV Fibers in the Freeze-Dried State

1988 ◽  
Vol 46 ◽  
pp. 170-171
Author(s):  
B. D. Athey ◽  
A. L. Stout ◽  
M. F. Smith ◽  
J. P. Langmore
Keyword(s):  
Reliable Method ◽  
Fiber Diameter ◽  
Quantitative Agreement ◽  
One Dimension ◽  
Fiber Axis ◽  
Two Dimensional ◽  
Fiber Density ◽  
Variable Diameter ◽  
Freeze Dried ◽  
Expected Values

Although there is general agreement that Inactive chromosome fibers consist of helically packed nucleosomes, the pattern of packing is still undetermined. Only one of the proposed models, the crossed-linker model, predicts a variable diameter dependent on the length of DNA between nucleosomes. Measurements of the fiber diameter of negatively-stained and frozen- hydrated- chromatin from Thyone sperm (87bp linker) and Necturus erythrocytes (48bp linker) have been previously reported from this laboratory. We now introduce a more reliable method of measuring the diameters of electron images of fibrous objects. The procedure uses a modified version of the computer program TOTAL, which takes a two-dimensional projection of the fiber density (represented by the micrograph itself) and projects it down the fiber axis onto one dimension. We illustrate this method using high contrast, in-focus STEM images of TMV and chromatin from Thyone and Necturus. The measured diameters are in quantitative agreement with the expected values for the crossed-linker model for chromatin structure

Effect of CT-based attenuation correction on uptake ratios in skeletal SPECT

2007 ◽  
Vol 46 (01) ◽  
pp. 38-42 ◽  
Author(s):  
V. Schulz ◽  
I. Nickel ◽  
A. Nömayr ◽  
A. H. Vija ◽  
C. Hocke ◽  
...  
Keyword(s):  
Vertebral Body ◽  
Facet Joint ◽  
One Dimension ◽  
Patient Specific ◽  
Data Sets ◽  
Facet Joints ◽  
Lumbar Vertebral Body ◽  
Ct System ◽  
Ct Data ◽  
Attenuation Corrected

SummaryThe aim of this study was to determine the clinical relevance of compensating SPECT data for patient specific attenuation by the use of CT data simultaneously acquired with SPECT/CT when analyzing the skeletal uptake of polyphosphonates (DPD). Furthermore, the influence of misregistration between SPECT and CT data on uptake ratios was investigated. Methods: Thirty-six data sets from bone SPECTs performed on a hybrid SPECT/CT system were retrospectively analyzed. Using regions of interest (ROIs), raw counts were determined in the fifth lumbar vertebral body, its facet joints, both anterior iliacal spinae, and of the whole transversal slice. ROI measurements were performed in uncorrected (NAC) and attenuation-corrected (AC) images. Furthermore, the ROI measurements were also performed in AC scans in which SPECT and CT images had been misaligned by 1 cm in one dimension beforehand (ACX, ACY, ACZ). Results: After AC, DPD uptake ratios differed significantly from the NAC values in all regions studied ranging from 32% for the left facet joint to 39% for the vertebral body. AC using misaligned pairs of patient data sets led to a significant change of whole-slice uptake ratios whose differences ranged from 3,5 to 25%. For ACX, the average left-to-right ratio of the facet joints was by 8% and for the superior iliacal spines by 31% lower than the values determined for the matched images (p <0.05). Conclusions: AC significantly affects DPD uptake ratios. Furthermore, misalignment between SPECT and CT may introduce significant errors in quantification, potentially also affecting leftto- right ratios. Therefore, at clinical evaluation of attenuation- corrected scans special attention should be given to possible misalignments between SPECT and CT.

SARI : A User-Oriented Data Bank System for Medical Applications

1976 ◽  
Vol 15 (02) ◽  
pp. 69-74
Author(s):  
M. Goldberg ◽  
B. Doyon
Keyword(s):  
Data Base ◽  
Personal Data ◽  
Data Bank ◽  
Medical Applications ◽  
Basic Principles ◽  
Base Management ◽  
General Data ◽  
Privacy Problem ◽  
Bank System ◽  
Made In

This paper describes a general data base management package, devoted to medical applications. SARI is a user-oriented system, able to take into account applications very different by their nature, structure, size, operating procedures and general objectives, without any specific programming. It can be used in conversational mode by users with no previous knowledge of computers, such as physicians or medical clerks.As medical data are often personal data, the privacy problem is emphasized and a satisfactory solution implemented in SARI.The basic principles of the data base and program organization are described ; specific efforts have been made in order to increase compactness and to make maintenance easy.Several medical applications are now operational with SARI. The next steps will mainly consist in the implementation of highly sophisticated functions.

Youth Culture Features in the Light of Preferred Role Models and Life Styles

2018 ◽  
Vol 5 (2) ◽  
pp. 163-174
Author(s):  
Amel Alić ◽  
Haris Cerić ◽  
Sedin Habibović
Keyword(s):  
Role Models ◽  
Family Background ◽  
Intercultural Sensitivity ◽  
Way Of Life ◽  
Social Sciences And Humanities ◽  
Life Styles ◽  
The Family ◽  
The Everyday ◽  
General Data ◽  
The University

Abstract The aim of this research was to determine to what extent different variables describe the style and way of life present within the student population in Bosnia and Herzegovina. In this sense, in addition to general data on examinees, gender differences were identified, the assessment of parental dimensions of control and emotion, overall family circumstances, level of empathy, intercultural sensitivity, role models, preferences of lifestyles, everyday habits and resistance and (or) tendencies to depressive, anxiety states and stress. The survey included a sample of 457 examinees, students of undergraduate studies at the University of Zenica and the University of Sarajevo, with a total of 9 faculties and 10 departments covering technical, natural, social sciences and humanities. The obtained data give a broad picture of the everyday life of youth and confirm some previously theoretically and empirically justified theses about the connection of the family background of students, everyday habits, with the level of empathy, intercultural sensitivity and preferences of the role models and lifestyles of the examinees.

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