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Showing papers by "University of Windsor published in 1981"


Journal ArticleDOI
TL;DR: Variational solutions to the Dirac equation in a discrete basis set are investigated in this paper, where the variational eigenvalues satisfy a generalized Hylleraas-Undheim theorem.
Abstract: Variational solutions to the Dirac equation in a discrete ${L}^{2}$ basis set are investigated. Numerical calculations indicate that for a Coulomb potential, the basis set can be chosen in such a way that the variational eigenvalues satisfy a generalized Hylleraas-Undheim theorem. A number of relativistic sum rules are calculated to demonstrate that the variational solutions form a discrete representation of the complete Dirac spectrum including both positive-and negative-energy states. The results suggest that widely used methods for constructing ${L}^{2}$ representations of the nonrelativistic electron Green's function can be extended to the Dirac equation. As an example, the relativistic basis sets are used to calculate electric dipole oscillator strength sums from the ground state, and dipole polarizabilities.

141 citations


Journal ArticleDOI
01 Aug 1981-Genetics
TL;DR: Estimates of genetic distances between the various races and subspecies were obtained by comparing cleavage maps of the mtDNAs with various restriction enzymes and suggest that M. molossinus is situated in a unique evolutionary position among Asian subspecies.
Abstract: The intra- and intersubspecific genetic distances between five subspecies of Mus musculus were estimated from restriction enzyme cleavage patterns of maps of mitochondrial DNA (mtDNA). The European subspecies, M. m. domesticus and Asian subspecies, M. m. bactrianus, M. m. castaneus, M. m. molossinus and M. m. urbanus were examined. For each subspecies, except M. m. urbanus, at least two local races from widely separated localities were examined. Intrasubspecific heterogeneity was found in the mtDNA cleavage patterns of M. m. bactrianus and M. m. castaneus. M. m. molossinus and M. m. domesticus, however, revealed no intrasubspecific heterogeneity. Four of the subspecies had distinct cleavage patterns. The fifth, M. m. urbanus, had cleavage patterns identical to those of M. m. castaneus with several enzymes. Estimates of genetic distances between the various races and subspecies were obtained by comparing cleavage maps of the mtDNAs with various restriction enzymes. Nucleotide sequence divergences of mtDNA between local races were estimated to be less than 0.4% in M. m. bactrianus and less than 0.3% in M. m. castaneus. The times of divergence of both subspecies were calculated to be 0.1--0.2 x 10(6) years. These values suggest that the intrasubspecific divergence began some 0.1--0.2 x 10(6) years ago. On the other hand, nucleotide sequence divergences between European subspecies M. m. domesticus and Asian subspecies M. m. bactrianus and M. m. castaneus were 7.1% ane 5.8%, respectively. The times of divergence were calculated to be 2.1--2.6 x 10(6) years. Further, the nucleotide sequence divergence and time of divergence between M. m. molossinus and the other two Asian subspecies were comparable to those between M. m. molossinus and M. m. domesticus (about 3% and 1 x 10(6) years, respectively). These results suggest that M. m. molossinus is situated in a unique evolutionary position among Asian subspecies.

127 citations


Journal ArticleDOI
TL;DR: In this article, the decay of metastable ions to the ground state by the simultaneous emission of two photons is calculated for all possible combinations of photon multipoles up to a factor of 10.
Abstract: Rates are calculated for the decay of metastable $2{s}_{\frac{1}{2}}$ ions to the ground state by the simultaneous emission of two photons. The calculation includes all relativistic and retardation effects, and all combinations of photon multipoles which make significant contributions up to $Z=100$. Summations over intermediate states are performed by constructing a finite-basis-set representation of the Dirac Green's function. The estimated accuracy of the results is \ifmmode\pm\else\textpm\fi{} 10 ppm for all $Z$ up to 100. The decay rates are about $20 {(\ensuremath{\alpha}Z)}^{2}$% larger than an earlier calculation by Johnson owing to the inclusion of higher-order retardation effects. The general question of gauge invariance in two-photon transitions is discussed.

112 citations


Journal ArticleDOI
T. Horvath1
TL;DR: Front-view line drawings of male and female physiques were rated for attractiveness; greater chest muscularity resulted in slightly higher attractiveness ratings; waist slimness was also judged attractive, particularly by female subjects.
Abstract: Front-view line drawings of male and female physiques were rated for attractiveness. Both subject sexes rated female physiques with greater curvature as less attractive. Male subjects' ratings were unaffected by breast size while female subjects showed slight negative evaluation of large breasts. Both subjects sexes rated broad shoulders as attractive in male physiques. Greater chest muscularity resulted in slightly higher attractiveness ratings; waist slimness was also judged attractive, particularly by female subjects.

90 citations


Journal ArticleDOI
TL;DR: In this paper, the electrical performance of gases under particle contamination has been investigated and a better understanding of the mechanism of breakdown and a reliable operation is obtained in a gas-filled system.
Abstract: The sensitivity of compressed gases to free and fixed conducting and non-conducting particle contaminants is a limiting factor in the design of electrical apparatus. Conducting particles which may result from damage to a gas-filled system constitute a serious threat to its safe and reliable operation. This deterioration in the dielectric strength of the gas largely depends on the type and shape of the particles, the type and pressure of the gas insulation, and the electric field. This paper reviews the electrical performance of gases under particle contamination. Further areas of work are proposed in order to obtain a better understanding of the mechanism of breakdown and a reliable operation under particle contamination.

88 citations


Journal ArticleDOI
TL;DR: Studies on two common and two rare clones from southwestern Ontario revealed significant differences in their intrinsic rates of increase, competitive abilities, rates of ephippial egg production, and lifespans.
Abstract: Natural populations of Daphnia pulex that reproduce by obligate parthenogenesis include a number of clones. Studies on two common and two rare clones from southwestern Ontario revealed significant differences in their intrinsic rates of increase, competitive abilities, rates of ephippial egg production, and lifespans. Environmental factors such as temperature and food type had large inluences on the rate of increase of each clone. Differences in rates of increase among clones were most pronounced at temperatures higher than those encountered in nature. In general, the covariance of life history traits among clones was high. The outcome of competitive encounters between clones was deterministic and in most cases was unaffected by temperature. Clones with high rates of increase tended to be better competitors than those with low rates of increase.

84 citations


Journal ArticleDOI
TL;DR: This article used three-wave panel studies in Great Britain, Canada, the Netherlands and the United States to measure the nature and extent of changes in individual partisanship over a period of three to six years.
Abstract: Among the most important elements in assessing the cross-national utility of the concept of party identification is its stability over time, in particular its stability relative to that of voting choice. This article utilizes three-wave panel studies in Great Britain, Canada, the Netherlands and the United States to measure the nature and extent of changes in individual partisanship over a period of three to six years. It is argued that there is substantial instability in party identification when all types of change are taken into account, and that the United States appears unique among the cases examined in its ability to combine stable partisanship with instability of voting behaviour for reasons relating to the particular nature of the American electoral system. In Britain and Canada, party identification exhibits a greater tendency to travel with vote, while in the Netherlands it is less stable than the vote itself.

79 citations


Journal ArticleDOI
TL;DR: An EPR study of the SO4 − radiation center revealed that KLiSO4 undergoes two phase transitions at approximate temperatures: −90°C and −20°C.
Abstract: An EPR study of the SO4 − radiation center revealed that KLiSO4 undergoes two phase transitions at approximate temperatures: −90°C and −20°C. A preliminary analysis of the line shapes indicates that the intermediate phase may be incommensurate. The rotation pattern of the EPR spectrum indicated that the low-temperature phases possesses fewer symmetry elements when compared with the (hexagonal) room-temperature phase. The g-factors in the two phases also differ considerably.

51 citations


Journal ArticleDOI
01 Jan 1981
TL;DR: The role of central processing deficiencies may play in the etiology of socio-emotional disturbances among learning disabled children is discussed in this paper, where it is taken as demonstrated that some forms of central information processing differences and/or deficits are responsible for the group of clinical disorders known as learning disabilities.
Abstract: The purpose of this article is to suggest the role(s) that central processing deficiencies may play in the etiology of socio-emotional disturbances among learning disabled children. In order to do this, we review some very recent studies carried out in our laboratory that have addressed this problem from a number of different perspectives. It is hoped that this review will serve to highlight some interesting features of this important problem. Some of the investigations discussed are currently being prepared for publication. The overview of the results is reported here simply to provide examples and ramifications of what we consider to be a reasonably heuristic approach to the investigation of this thorny issue. In this discussion, it is taken as demonstrated that some forms of central information processing differences and/or deficits are responsible for the group of clinical disorders known as learning disabilities. There is evidence (Benton 1975; Rourke 1975,1978a, 1978b) that is quite consistent with the view that various types and degrees of disordered brain function are responsible for the information processing deficiencies that character ize at least the majority of children who are learning disabled.

45 citations


Journal ArticleDOI
TL;DR: In this paper, various types of spacers used in gas-filled systems are reviewed and the flashover performance under contaminated conditions is also evaluated, in order to obtain a better understanding of the mechanism of flashover and towards the design of an efficient and reliable compressed gas insulated system.
Abstract: The spacer surface in a compressed gas insulated apparatus constitutes the weakest electrical location in the system. Discharges originating at the spacer-gas-electrode interface and the electric field distortion at the spacer surface may cause surface flashover. The presence of water vapor, conducting particles, and other contaminants may alter the flashover characteristics of the spacer. This paper reviews the various types of spacers used in gas-filled systems. The flashover performance of spacers under contaminated conditions is also evaluated. Further areas of work on the flashover of spacers are proposed in order to obtain a better understanding of the mechanism of flashover and towards the design of an efficient and reliable compressed gas insulated system.

45 citations


Journal ArticleDOI
TL;DR: In this paper, it was shown that the sodium sulfonates of 2, 4-dichloro-and 2,4-dibromophenol when employed in the presence of 4-AAP produce useful and sensitive, colorimetric, cosubstrate systems.

Journal ArticleDOI
TL;DR: In this article, it was shown that the loss of electron scattering flux through dielectronic recombination can be quite significant for highly charged ions, thus reducing the contribution of autoionizing resonances to scattering cross sections and hence excitation rates.
Abstract: It is shown that the loss of electron scattering flux through dielectronic recombination can be quite significant for highly charged ions, thus reducing the contribution of autoionizing resonances to scattering cross sections and hence excitation rates. This process is likely to be of importance in analyzing line emission from high-temperature plasmas. Detailed calculations are carried out for ${\mathrm{O}}^{6+}$ and ${\mathrm{Fe}}^{24+}$. Employing the present formulation, the averaged cross sections for dielectronic recombination may also be computed.

Journal ArticleDOI
TL;DR: In this paper, the anion is a novel cluster based on a tetrahedral Zn4S10 kernel, and the structure is determined by X-ray crystallography.

Journal ArticleDOI
TL;DR: The commercially available alloys for hydrogen storage are LaNi5-based, FeTi-based and Mg-based alloys as mentioned in this paper, and these alloys provide an efficient and safe method for storing hydrogen.
Abstract: Metal hydrides provide an efficient and safe method for storing hydrogen. Hydrogen can be stored indefinitely and released as needed for a number of energy usages. The commercially available alloys for storage are LaNi5-based, FeTi-based, and Mg-based alloys. In this paper we conduct an overall review of these alloys and compare them with other alloys, and in particular with zirconium based binaries and pseudobinaries. Also described in this paper is the apparatus required for hydrogen absorption and desorption experiments.

Journal ArticleDOI
TL;DR: In this paper, the authors analyzed 30 protocol sentences derived from Freud's theories of Binswanger, Freud, and Kelly and found that isolation, immaturity and desire for freedom more frequently characterized the simulated notes than the genuine notes.
Abstract: Involved the deduction of 30 protocol sentences; 10 each for the theories of Binswanger, Freud, and Kelly. Naive judges noted the incidence of contents that corresponded to the protocol sentences in 33 genuine and 33 simulated notes. A coefficient of concordance of .70 indicated adequate interjudge reliability. Only the protocol sentences derived from Freud discriminated as a set in favor of the genuine notes. Statements that indicated loss and an identification with a lost person were found more frequently in genuine notes. Statements of isolation, immaturity and desires for freedom more frequently characterized the simulated notes. Implications of the results are discussed. Language: en

Book
01 Jan 1981

Journal ArticleDOI
TL;DR: In this paper, the work in steady, viscous, incompressible flows is extended to general variably inclined, but nowhere aligned, flows with the objective of obtaining some exact solutions.
Abstract: By a variably inclined MHD plane flow we mean a flow in which the magnetic and velocity fields are coplanar, the angle between these vector fields is variable and all the flow variables are functions of two coordinates and time. No work seems to have been done for these general plane MHD flows, even in the steady case. In the present paper the work in steady, viscous, incompressible flows is extended to general variably inclined, but nowhere aligned, flows with the objective of obtaining some exact solutions. We employ the hodograph transformation, one of the strong analytical methods, to find these solutions.

Journal ArticleDOI
TL;DR: In this article, a simple transformation of x in the more common situation of positive correlation between y and x, to permit a product method of estimation rather than a ratio method was proposed. But such cases are not frequent in survey practice.
Abstract: Summary The product method of estimation (Murthy, 1964) complements the ratio method when the study variate, y, and an auxiliary variate, x, have negative correlation. However, such cases are not frequent in survey practice. This paper suggests a simple transformation of x in the more common situation of positive correlation between y and x, to permit a product method of estimation rather than a ratio method. This leads to the advantage that the bias and mean square error have exact expressions. The technique developed by Quenouille (1956) and applied by Shukla (1976) is used for making the estimator unbiased. The minimum variance situation is investigated. Two numerical examples are included. The case of negative correlation is also examined.

Journal ArticleDOI
TL;DR: The differences in microhabitat use among four species of heteromyid rodents at low and at high population densities are studied to find out whether these differences are density dependent or driven by changes in rodent abundance.
Abstract: Among some species of Sonoran Desert rodents microhabitat differences are density dependent. I studied the differences in microhabitat use among four species of heteromyid rodents (Dipodomys merriami, Perognathus amplus, P. baileyi, and P. penicillatus) at low and at high population densities. Microhabitats are defined by the abundance and size distribution of desert shrubs. During a period of low population density the rodent species showed substantial microhabitat differentiation. Following a large increase in pocket mouse (Perognathus spp.) numbers differences in microhabitat use between species disappeared. The lack of microhabitat differentiation at high density is due to microhabitat shifts rather than an expansion in the number of microhabitats used. The shifts lead to increased similarity among species in microhabitat use. Microhabitat overlap is not constant but it is highly variable and sensitive to changes in rodent abundance.


Journal ArticleDOI
TL;DR: In this article, sport psychologists have attempted to study spectator violence by focusing on the aggression levels of individual fans and sport sociologists have used collective behavior theories in their attempts to identify possible determinants of crowd violence.
Abstract: The incidence of spectator violence at sporting events appears to be increasing at an alarming rate in present-day society. Research specifically dealing with crowd violence has also increased concomitantly. This article selectively reviews spectator violence research in an effort to articulate past and present trends. Traditionally, sport psychologists have attempted to study spectator violence by focusing on the aggression levels of individual fans. In turn, sport sociologists have used collective behavior theories in their attempts to identify possible determinants of crowd violence. It seems incumbent upon the researchers of future studies in this area to look to hypothetical questions that encompass both schools of thought.The need for an understanding of spectator violence in sport environments is real. During the past few years, several tragedies related to sport spectator violence have been reported. If similar incidents are to be avoided, the phenomenon of spectator violence must be carefully stu...

Journal ArticleDOI
TL;DR: This study shows that N e in some highly polymorphic populations such as those of the house mouse, Mus musculus, may be considerably smaller than previously thought.
Abstract: Theoretical studies concerned with genetic variability in natural populations have generally considered genetically effective population sizes ( N e ) of 104 or greater. This study shows that N e in some highly polymorphic populations such as those of the house mouse, Mus musculus , may be considerably smaller. The mouse populations considered inhabit corn cribs in southwestern Ontario and are polymorphic at a number of loci. They are ideal for this work because the entire population can be collected over a short period of time, and because the various cribs provide replicas of the same general microhabitat. The mean population sizes were 14.4 and 54.4 in the winter and summer, respectively. No correlation was observed between population size and crib size. N e , based on the mean numbers of mice observed in the winter and summer collections and the assumption that all mice are reproductively active, was approximately 20. This could be as high as 70 in some populations and as low as 10 in others. To determine factors that might affect population size, data were collected on 16 environmental variables. Stepwise multiple regression analysis indicated that four environmental variables, compass orientation of a crib ( P < 0.001), number of predators ( P < 0.01), distance from an east-west line ( P < 0.01), and distance from a north-south line ( P < 0.05) were significantly associated with population size. Based on the male:female ratio in the summer populations, only one crib appeared to be fully utilized by the mice. In this exception, a crib with a high population density, a deficiency of males suggested competition for territory.


Journal ArticleDOI
TL;DR: In this paper, the authors present detailed closed-form expressions for the evaluation and numerical calculation of atomic spin-orbit matrix elements in the unitary group approach and describe a minicomputer implementation of the calculations.

Proceedings ArticleDOI
01 Apr 1981
TL;DR: The method is based on the properties of multivariable positive real functions, and results in an approach wherein the stability of the filter is guaranteed.
Abstract: This paper presents a method for the design of (N-D) analog and digital recursive filters. The method is based on the properties of multivariable positive real functions, and results in an approach wherein the stability of the filter is guaranteed. The method is illustrated by examples.


Journal ArticleDOI
TL;DR: Though the sites of UV inactivation in spores can only be postulated at present, it is apparent that the initial stages of germination occur independently of the UV sensitive sites, however, the final stage of Germination (emergence), however, is dependent on UV sensitive functions.
Abstract: — The spore germination in Dictyostelium discoideum consists of four stages: activation, postactivation lag, swelling and emergence. Ultraviolet irradiation (total fluence of 250 J/m2) of spores at any time prior to late spore swelling allows full swelling, but inhibits the emergence of myxamoebae. In the case of freshly activated spores, a UV exposure time of 30 s (total fluence of 50 J/m2) is sufficient to reduce emergence to about 6% when measured after 24 h of incubation. This same fluence results in about 10% viability as measured by plaque forming ability. Experiments utilizing ‘fractionated exposures’ result in the same percentage inhibition of emergence as that found for ‘single exposures’ provided the total fluence is equivalent. The higher fluences (250 J/m2) which completely prevent emergence, do not affect the endogenous oxygen uptake of spores during swelling. Ultraviolet light irradiated spores respond to the same activation and deactivation treatments as control unirradiated spores. Ultraviolet irradiation after late spore swelling allows emergence to occur in only a small fraction of the population. This fraction of cells which can emerge after UV treatment is said to have passed a ‘competence point’, which is believed to be the time when all the events necessary for emergence have been completed. Though the sites of UV inactivation in spores can only be postulated at present, it is apparent that the initial stages of germination (activation, postactivation lag and spore swelling) occur independently of the UV sensitive sites. The final stage of germination (emergence), however, is dependent on UV sensitive functions.

Journal ArticleDOI
TL;DR: A thin-foil electron metallographic and electron diffraction study was made of hydrides in Zr-2.5wt%Nb alloy nuclear reactor pressure tubing containing 7-300 ppm by weight hydrogen as discussed by the authors.

01 Dec 1981
TL;DR: The commercially available alloys for hydrogen storage are LaNi5-based, FeTi-based and Mg-based alloys as discussed by the authors, and these alloys provide an efficient and safe method for storing hydrogen.
Abstract: Metal hydrides provide an efficient and safe method for storing hydrogen. Hydrogen can be stored indefinitely and released as needed for a number of energy usages. The commercially available alloys for storage are LaNi5-based, FeTi-based, and Mg-based alloys. In this paper we conduct an overall review of these alloys and compare them with other alloys, and in particular with zirconium based binaries and pseudobinaries. Also described in this paper is the apparatus required for hydrogen absorption and desorption experiments.

Journal ArticleDOI
TL;DR: In this article, a reinvestigation of the vibrational spectra of CH3SiF3 has led to a more complete assignment than is currently available, and an extension of the methods used has prompted a reassignment of the skeletal modes of the CH3GeF3 and is believed to have lead to a settling of the assignment of CH 3GeCl3.