3,506 research outputs found
Time-like and space-like electromagnetic form factors of nucleons, a unified description
The extended Lomon-Gari-Kr\"umpelmann model of nucleon electromagnetic form
factors, which embodies \rho, \rho', \omega, \omega' and \phi vector meson
contributions and the perturbative QCD high momentum transfer behavior has been
extended to the time-like region. Breit-Wigner formulae with momentum-dependent
widths have been considered for broad resonances in order to have a
parametrization for the electromagnetic form factors that fulfills, in the
time-like region, constraints from causality, analyticity, and unitarity. This
analytic extension of the Lomon-Gari-Kr\"umpelmann model has been used to
perform a unified fit to all the nucleon electromagnetic form factor data, in
the space-like and time-like region (where form factor values are extracted
from e+e- nucleon-antinucleon cross sections data). The knowledge of the
complete analytic structure of form factors enables predictions at extended
momentum transfer, and also of time-like observables such as the ratio between
electric and magnetic form factors and their relative phase.Comment: 21 pages, 17 figures. Accepted for publication in PR
Quasiconformal variation of slit domains
We use quasiconformal variations to study Riemann mappings
onto variable single slit domains when the slit is the tail of an appropriately
smooth Jordan arc. In the real analytic case our results answer a question of
Dieter Gaier and show that the function κ in Löwner's differential equation is
real analytic
Ownership Structures
In this paper, we analyse the effects of the massive Russian privatisation programme on the ownership of Russian firms and on the behaviour of formerly state owned enterprises. A large random sample of Russian firms is used to investigate the emerging ownership structures, patterns of control and enterprise behaviour. We find that workers have become the dominant owners in a majority ig Russian private firms; 65% of the total as against 19% being manager owned and 16% of being outsider owned. Higher- ownership appears to confer significantly more influence over decision-making on managers and outsiders, but not on workers. Most importantly however, we find no evidence that privatisation affects any major area of enterprise behaviour or performance.
Media Technology, Adult Education, and National Development: The Malaysian Experience
This article explores the use of media technology in Malaysia's adult education programmes within an overall
national development context. A qualitative methodology incorporating non-participant observation, reportorial
interviews, and archival collection of news articles, speeches, and other printed materials was used to investigate
three areas of research questions: I) defining basic and functional literacy in Malaysia, 2) the role of media
technology in adult education, and 3) the social impact mediated and media-enhanced educational formats on
personal, social, cultural, and political development. The theoretical framework for the study includes national
development models, adult literacy in developing countries, and distance education as an educational delivery
system, with the analysis of the results within a neo-Modernization model of national development. Although
no evidence of systematic adult basic education in Malaysia was found, there are diverse nonformal functional
literacy activities for adults, many ofwhich are mediated or media-enhanced. The study questions the appropriateness
of distance education techniques for teaching Malaysian adults who are no longer in the formal school
system. The implications of the findings for Malaysian educators, administrators, and policymakers, and the
impact of these results on national development theory are discussed
Probability of Success in Business Mathematics
One of the problems of frequent concern to educators is that of predicting achievement of students so that both potentially superior and slow students can be identified early in a course for the purpose of giving adequate attention to such cases. The general method of the procedure to be discussed here might be applicable to many situations, but it is especially applicable in mathematics
Fundamental Aspects of the Mixing of Plastic Materials
1. The thesis falls into three main sections. In the first the theoretical aspects of the problem are considered, and a rational basis for analysis of experimental results derived. The second section describes the development of a new technique for measuring the progress of mixing, and its application to mixing machines. Findings are reviewed in the final section. The theoretical ideas developed on the assessment of mixing offer a background, to include less comprehensive but more experimentally convenient measures of this state of mixing. A concentration distribution spectrum is proposed, as giving fundamental meaning to the ideas of "clumping" of the components which make up a mixture. Analysis of the influence, on sample composition measures, of sample size, emphasises its association with scale effects and the progress of mixing, and this whole topic is discussed in some detail. All available evidence on rates of mixing is shown to indicate that, over a substantial range, a first order kinetic mechanism applies. The influence of sample size on rate determinations is shown to be small, a finding of value in interpreting experimental results and in scaling up from laboratory trials. Possible measures of efficiency are considered, and though the fundamental criteria are elusive, practical parameters are suggested and developed. An experimental method of following the progress of mixing of flour doughs was evolved, and is described in detail. Analysis is carried out by photographing the pattern produced by colour differentiated components. The photographic plates are then scanned, using a photometric technique, to give a measure of the mixing. This measure is shown to be reproducible, self consistent, and in agreement with such theoretical predictions as can be made. The method is first applied to investigate the theoretical concepts, and then to assess the performance characteristics of two types of laboratory mixers. This produces evidence that the "sigmoid arm" kneading machines, extensively used in practice, are less efficient than other types. Finally, it is shown that the method can he extended readily to a commercial scale mixing machine
Analytic pion form factor
The pion electromagnetic form factor and two-pion production in electron-positron collisions are simultaneously fitted by a vector dominance model evolving to perturbative QCD at large momentum transfer. This model was previously successful in simultaneously fitting the nucleon electromagnetic form factors (spacelike region) and the electromagnetic production of nucleon-antinucleon pairs (timelike region). For this pion case dispersion relations are used to produce the analytic connection of the spacelike and timelike regions. The fit to all the data is good, especially for the newer sets of timelike data. The description of high-q[superscript 2] data, in the timelike region, requires one more meson with ρ quantum numbers than listed in the 2014 Particle Data Group review.United States. Dept. of Energy (Award DE-SC0011090
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