Showing papers by "University of Maryland, College Park published in 1980"
TL;DR: In weak-interaction models with spontaneous parity nonconservation, this article obtained the following formula for the neutrino mass, valid for each lepton generation, which relates the maximality of observed parity non-conservation at low energies to the smallness of neutrinos masses.
Abstract: In weak-interaction models with spontaneous parity nonconservation, based on the gauge group $\mathrm{SU}{(2)}_{L}\ensuremath{\bigotimes}\mathrm{SU}{(2)}_{R}\ensuremath{\bigotimes}\mathrm{U}(1)$, we obtain the following formula for the neutrino mass: ${m}_{{\ensuremath{
u}}_{e}}\ensuremath{\simeq}\frac{{{m}_{e}}^{2}}{g{m}_{{W}_{R}}}$, where ${W}_{R}$ is the gauge boson which mediates right-handed weak interactions. This formula, valid for each lepton generation, relates the maximality of observed parity nonconservation at low energies to the smallness of neutrino masses.
4,895 citations
TL;DR: In this article, the authors present an agreement between Publications mathematiques de l'I.H.E.S. and les conditions generales d'utilisation (http://www.numdam.org/legal.php).
Abstract: © Publications mathematiques de l’I.H.E.S., 1980, tous droits reserves. L’acces aux archives de la revue « Publications mathematiques de l’I.H.E.S. » (http://www. ihes.fr/IHES/Publications/Publications.html), implique l’accord avec les conditions generales d’utilisation (http://www.numdam.org/legal.php). Toute utilisation commerciale ou impression systematique est constitutive d’une infraction penale. Toute copie ou impression de ce fichier doit contenir la presente mention de copyright.
946 citations
Book•
01 Jan 1980TL;DR: Signs in the theatre: Prague structuralism and the theatrical sign Typologies of the sign as discussed by the authors Theoretically, the sign is a symbol of the presence of the audience.
Abstract: General Editor's Preface. Acknowledgements. 1. Preliminaries: Semiotics and Poetics: The Semiotics Enterprise How Many Semiotics? The material. 2. Foundations: Signs in the Theatre: Prague structuralism and the theatrical sign Typologies of the sign. 3. Theatrical Communication: Codes, Systems and the Performance Text: Elements of theatrical communication Theatrical Systems and Codes Theatrical competence: frame, convention and the role of the audience. 4. Dramatic Logic: The construction of the dramatic world Dramatic action and time Actant, dramatis persona and the dramatic model. 5. Dramatic Discourse: Dramatic Communication Context and deixis Universe of discourse and co-text Speech acts The said and the unsaid: implicatures and figures Textuality Towards a dramatological analysis. 6. Concluding Comments: Theatre, Drama, Semiotics: Dramatic Text/performance text A united enterprise? Suggestions for further reading. Bibliography. Index.
761 citations
TL;DR: In this paper, the authors generalize the response given long ago by a number theorist to a student who asked “Why is number theory useful?” His reply: “It is useful because one can get a Ph.D with it!”
Abstract: Why is the study of the relativistic theory of many-electron bound systems interesting and useful? As regards utility, a minimal answer can be given by generalizing the response given long ago by a number theorist to a student who asked “Why is number theory useful?” His reply: “It is useful because one can get a Ph.D. with it!”
623 citations
TL;DR: The theory of equalizing differences as discussed by the authors asserts that workers receive compensating wage premiums when they accept jobs with undesirable non-wage characteristics, holding the worker's characteristics constant, and longitudinal data are used to test this conjecture.
Abstract: The theory of equalizing differences asserts that workers receive compensating wage premiums when they accept jobs with undesirable nonwage characteristics, holding the worker's characteristics constant. Previous research provides only inconsistent support for the theory, with wrong-signed or insignificant estimates of these wage premiums fairly common. An oft-cited reason for these anomalies is that important characteristics of the worker remain unmeasured, biasing the estimates. In this paper, longitudinal data are used to test this conjecture. Although such data improve the control for worker characteristics, the plausibility of the estimates is not markedly improved. Alternative explanations for these results are considered. "It's indoor work and no heavy lifting." —Senator Robert Dole, explaining why he wanted to be Vice President.
580 citations
TL;DR: A review examining issues and topics concerning systematic modes of instruction designed to produce environments that shape behavior to satisfy stated objectives is presented in this article, where training is defined as the acquisition of skills, concepts, or attitudes that results in improved performance in an on-the-job environment.
Abstract: This review examines issues and topics concerning systematic modes of instruction designed to produce environments that shape behavior to satisfy stated objectives. Training here is defined as the acquisition of skills, concepts, or attitudes that results in improved performance in an on-the-job environment. Even a cursory inspection of this review displays the diverse nature of literature in this field which includes such topics as: need assessment techniques, evaluation methodology, and particular modes of instruction; in addition, there are topics with social and political implications such as training for second careers and training hard-core unemployed youth. This is the first examination of the topic in this series since J. P. Campbell's (1971) review. Computer searches covering the period since his review produced over 3000 references from the Educational Resources Information Center and Psychological Abstracts bibliographic data bases. The resulting eye strain was partially alleviated by a set of ...
530 citations
TL;DR: In this article, a relationship between the Lyapunov numbers of a map with a strange attractor and the dimension of the attractor has been conjectured and the conjecture is numerically tested with use of several different maps, one of which results from a system of ordinary differential equations occurring in plasma physics.
Abstract: A relationship between the Lyapunov numbers of a map with a strange attractor and the dimension of the strange attractor has recently been conjectured. Here, the conjecture is numerically tested with use of several different maps, one of which results from a system of ordinary differential equations occurring in plasma physics. For the cases tested, the conjecture is verified to within the obtained accuracy.
401 citations
TL;DR: In this paper, the authors report on the existing literature models for rail transportation with two goals in mind: (a) to collect and categorize rail modelling efforts, and (b) to position the rail-related literature in the context of other transportation models and provide an introduction to this field for nonspecialists.
307 citations
TL;DR: The view that the concept of social network is a useful tool in examining both the functional and the dysfunctional influences of one's primary group on individual adaption is adopted.
Abstract: The intent of this paper is to present a representative, though not exhaustive, overview of the current literature on social networks, with an emphasis on research linking social networks to psychological adaptation. This overview includes a review of social network concepts; and analysis of the multiple determinants of social networks; an analysis of the varied effects of social networks; and the implications for policies and practices of community mental health centers. This paper adopts the view that the concept of social network is a useful tool in examining both the functional and the dysfunctional influences of one's primary group on individual adaption.
306 citations
TL;DR: In this article, two studies tested an attributional model of leaders' responses to poor performance and found that consensus, consistency, and distinctiveness helped in determining attributions, and that internal attributions led to punitive responses on the part of supervisors.
270 citations
TL;DR: In their continued considerations of political inequality, urban scholars are especially concerned with less visible influences surrounding community decision-making, and have employed such concepts as potential power, nondecision making, and anticipated reactions as mentioned in this paper.
Abstract: In their continued considerations of political inequality, urban scholars are especially concerned with less visible influences surrounding community decision making, and have employed such concepts as potential power, nondecision making, and anticipated reactions. However, these concepts leave some patterns of influence unexplained. There is also a dimension of power in which durable features of the socioeconomic system confer advantages and disadvantages on groups in ways that predispose public officials to favor some interests at the expense of others. Public officials make their decisions in a context in which strategically important resources are hierarchically arranged. Because this system of stratification leaves public officials situationally dependent on upper-strata interests, it is afactor in all that they do. Consequently, system features lower the opportunity costs of exerting influence for some groups and raise them for others. Thus socioeconomic inequalities put various strata on different political footings.
TL;DR: The dynamic behavior of a family of disease models for a heterogeneous population and asymptotic patterns of disease prevalence are related to contact and disease duration parameters for gonorrhea are discussed.
Abstract: The dynamic behavior of a family of disease models for a heterogeneous population is discussed. Asymptotic patterns of disease prevalence are related to contact and disease duration parameters for gonorrhea. Estimates show the effects of particularly infectious subgroups within a population.
TL;DR: The results indicate significant correlations between proboscis length and time spent by bees on flowers, and suggest that bumblebees of short probosc is length prefer and are more efficient on short corolla tubes.
Abstract: The rates at which bumblebees of different proboscis lengths forage on flowers of a series of corolla tube lengths were determined. The results indicate significant correlations between proboscis length and time spent by bees on flowers. Bumblebees of long proboscis length can forage significantly faster than bees of shorter proboscis length on flowers with long corolla tubes. There is also evidence which suggests that bumblebees of short proboscis length prefer and are more efficient on short corolla tubes. These results support the use of proboscis length as a morphological indicator of resource utilization in bumblebees.
Book•
01 Jan 1980TL;DR: In this paper, Americans in Transition: Life Changes as Reasons for Adult Learning is presented as the main reason for adult learning in the United States, with a focus on mental health.
Abstract: (1982). Americans in Transition: Life Changes as Reasons for Adult Learning. The Journal of Higher Education: Vol. 53, No. 2, pp. 233-235.
TL;DR: Results concerning the NP-difficulty of several network reliability analysis problems are unified and in several cases generalized to wider classes of measures.
Abstract: This paper considers the difficulty of computing several measures of network reliability on directed and undirected networks. Results concerning the NP-difficulty of several network reliability analysis problems are unified and in several cases generalized to wider classes of measures. Reductions are also given that relate network reliability problems on directed and undirected networks and problems with and without node failures.
TL;DR: Horizontal binocular eye and head movements of 4 human subjects were recorded by means of the sensor coil-rotating magnetic field technique while they actively rotated their heads about a vertical axis and maintained fixation on a distant target.
TL;DR: In this article, a new method for controlling millimeter-wave propagation in semiconductor waveguides-optical control was demonstrated, and phase shifts as high as 300°/cm at 94 GHz were observed accompanied by less than 1 dB insertion loss.
Abstract: We have demonstrated a new method for controlling millimeter-wave propagation in semiconductor waveguides-optical control. Phase shifts as high as 300°/cm at 94 GHz were observed accompanied by less than 1 dB insertion loss. A theoretical model has been developed to account in detail for the observed behavior. Extension of this technique to ultra-fast switching and gating of millimeter-wave signals is also described. Millimeter-wave pulsewidths as short as 1 ns and variable to tens of nanoseconds can readily be obtained.
TL;DR: The results are compared with previous work on probabilistic relaxation labeling, and examples are given from the image segmentation domain, to applications of the new scheme in text processing.
Abstract: Let a vector of probabilities be associated with every node of a graph. These probabilities define a random variable representing the possible labels of the node. Probabilities at neighboring nodes are used iteratively to update the probabilities at a given node based on statistical relations among node labels. The results are compared with previous work on probabilistic relaxation labeling, and examples are given from the image segmentation domain. References are also given to applications of the new scheme in text processing.
TL;DR: An algorithm is presented for constructing a quadtree for a region given its boundary in the form of a chain code that reveals that its execution time is proportional to the product of the perimeter and the log of the diameter of the region.
Abstract: An algorithm is presented for constructing a quadtree for a region given its boundary in the form of a chain code. Analysis of the algorithm reveals that its execution time is proportional to the product of the perimeter and the log of the diameter of the region.
TL;DR: The authors examines the proposition that all international regimes are social institutions and suggests that regimes are dependent upon the maintenance of convergent expectations among actors, formalization is not a necessary condition for the effective operation of regimes, and regimes are always created rather than discovered.
Abstract: Although we live in a world of international regimes, the scholarly literature on them remains rudimentary, especially in analytic terms. This essay examines the proposition that all international regimes are social institutions, even though there is great variation among them. Among other things, this suggests that regimes are dependent upon the maintenance of convergent expectations among actors; formalization is not a necessary condition for the effective operation of regimes; and regimes are always created rather than discovered. A conceptual framework and a research agenda for the comparative study of international regimes, as laid out in this essay, would guide studies of specific regimes and improve our ability to reach general conclusions about this fundamental, yet poorly understood, international phenomenon.
TL;DR: This paper presents an algorithm for converting from quadtrees to a simple class of boundary codes and is shown to have an execution time proportional to the perimeter of the region.
Abstract: There has been recent interest in the use of quadtrees to represent regions in an image. It thus becomes desirable to develop efficient methods of conversion between quadtrees and other types of region representations. This paper presents an algorithm for converting from quadtrees to a simple class of boundary codes. The algorithm is shown to have an execution time proportional to the perimeter of the region.
TL;DR: In this article, it was shown that a vacuum state must be bounded by rarefaction waves and that compression vacuums can give rise to compression waves which eventually form shock.
TL;DR: The methylation process may be an important step in the detoxification process for microorganisms exposed to high concentrations of selenium in sewage sludge and soil.
Abstract: Inorganic selenium compounds are converted to volatile methylated species (dimethyl selenide, dimethyl diselenide, and dimethyl selenone or methyl methylselenite) by microorganisms in sewage sludge and soil. In the absence of added selenium, no volatile selenium compounds were detected. All samples were evaluated without the addition of nutrients and in the presence of air or nitrogen. The methylation process may be an important step in the detoxification process for microorganisms exposed to high concentrations of selenium.
TL;DR: Although the aromatic content of terrestrial humic acid was found to be lower than expected, the aromaticity appears to be a specific discriminator of terrestrial/aquatic source types.
TL;DR: Cooperating local parallel processes can be used as aids in assigning numerical or symbolic labels to image or scene parts in low-level vision.
TL;DR: In this paper, it was shown that any I.E.T. is not mixing with respect to any Borel invariant measure, and the same is true for any special flow constructed by any I E.T and any "roof" function of bounded variation.
Abstract: An interval exchange transformation (I.E.T.) is a map of an interval into itself which is one-to-one and continuous except for a finite set of points and preserves Lebesgue measure. We prove that any I.E.T. is not mixing with respect to any Borel invariant measure. The same is true for any special flow constructed by any I.E.T. and any “roof” function of bounded variation. As an application of the last result we deduce that in any polygon with the angles commensurable with π the billiard flow is not mixing on two-dimensional invariant manifolds.
TL;DR: In this paper, the influence of biological and physical factors on DO dynamics in an estuarine ecosystem near Calvert Cliffs, Chesapeake Bay was examined for the first time.
01 Jan 1980
TL;DR: Oxygen and nutrient fluxes across the sediment-water interface were measured over an annual cycle in the turbid portion of the Patuxent Estuary as mentioned in this paper, and the results indicated that nitrogen fluxes represent an important source to the water column in summer when photosynthetic demand is high and water column stocks are low, and, conversely, serve as a sink in winter when demand is low and Water column stocks high, thereby serving a buffering function between supply and demand.
Abstract: Oxygen and nutrient fluxes across the sediment-water interface were measured over an annual cycle in the turbid portion of the Patuxent Estuary. Benthic respiration rates ranged from 0.5 to 4.1 g O 2 m –2 d –1 and were positively correlated with temperature and primary production. Net fluxes of ammonium (NH 4 + ) and dissolved inorganic phosphorus (DIP) ranged from –105 to 1584 μg-at N m –2 h –1 and 1 to 295 μg-at P m –2 h –1 respectively. These rates, which were positively correlated with temperature, are among the highest yet reported in the literature. Fluxes of nitrate plus nitrite were small during summer when water column concentrations were low, but high and directed into the sediments during winter when water column concentrations were high. In general it appears that nutrient fluxes across the sediment-water interface represent an important source to the water column in summer when photosynthetic demand is high and water column stocks are low and, conversely, serve as a sink in winter when demand is low and water column stocks high, thereby serving a “buffering” function between supply and demand. A simple budget of sediment-water exchanges and storages of nitrogen indicated that, of the total particulate nitrogen deposited annually onto the sediments, about 34% was returned to the water column as NH 4 + , 41% was stored as particulate nitrogen in the sediments and, by difference, we estimated that the remaining 24% was denitrified. We also observed considerable uptake of nitrate by the sediments during winter months (1.1 g-at m –2 y –1 ), suggesting an additional source of annual denitrification, since this nitrate uptake was not accompanied by ammonium release back to the water column. The ecological implications of these large nutrient fluxes are discussed in terms of sources and sinks of nutrients, as well as couplings with carbon productivity.