Showing papers by "University of Wisconsin–Milwaukee published in 1971"

Quantized fields and particle creation in expanding universes. ii.

Abstract: Spin-0 fields of arbitrary mass and massless fields of arbitrary spin are considered. The equations governing the fields are the covariant generalizations of the special-relativistic free-field equations. The metric, which is not quantized, is that of a universe with an expanding (or contracting) Euclidean 3-space. The spin-0 field of arbitrary mass is quantized in the expanding universe by the canonical procedure. The quantization is consistent with the time development dictated by the equation of motion only when the boson commutation relations are imposed. This consistency requirement provides a new proof of the connection between spin and statistics. We show that the particle number is an adiabatic invariant, but not a strict constant of the motion. We obtain an expression for the average particle density as a function of the time, and show that particle creation occurs in pairs. The canonical creation and annihilation operators corresponding to physical particles during the expansion are specified. Thus, we do not use an S-matrix approach. We show that in a universe with flat 3-space containing only massless particles in equilibrium, there will be precisely no creation of massless particles as a result of the expansion, provided the Einstein field equations without the cosmological term are correct. Furthermore, in a dust-filled universe with flat 3-space there will be precisely no creation of massive spin-0 particles in the limit of infinite mass, again provided that the Einstein field equations are correct. Conversely, without assuming any particular equations, such as the Einstein equations, as governing the expansion of the universe, we obtain the familiar Friedmann expansions for the radiation-filled and the dust-filled universes with flat 3-space. We only make a very general and natural hypothesis connecting the particle creation rate with the macroscopic expansion of the universe. In one derivation, we assume that in an expansion of the universe in which a particular type of particle is predominant, the type of expansion approached after a long time will be such as to minimize the average creation rate of that particle. In another derivation, we use the assumption that the reaction of the particle creation back on the gravitational field will modify the expansion in such a way as to reduce, if possible, the creation rate. This connection between the particle creation and the Einstein equations is surprising because the Einstein equations themselves played no part at all in the derivation of the equations governing the particle creation. Finally, on the basis of a so-called infinite-mass approximation, we argue that in the present predominantly dust-filled universe, only massless particles of zero spin might possibly be produced in significant amounts by the present expansion. In this connection, we show that massless particles of arbitrary nonzero spin, such as photons or gravitons, are not created by the expansion, regardless of its form.

Chemical exchanges between sediments and water in the great lakes-speculations on probable regulatory mechanisms1

Abstract: As long as the oxygen concentration at the sediment surface does not fall below 1 or 2 mg/liter, typical deep-water sediments in the Great Lakes will probably be found to exert a measurable but quantitatively unimportant influence oa the chemistry of the overlying waters. This conclusion is supported by the case of Windermere. The sequence of more conspicuous changes that take place when the oxygen does fall below 1 mg/liter at the interface is illustrated by the case of Esthwaite Water, representative of events in lakes where biological production or organic pollution is high, where the subthermocline volume is relatively small, or both. A progressive decline in oxygen comncentration from 2 mg/liter to analytical zero at the interface was accompanied by a fall in electrode potential in the upper few millimeters of sediment, co~rrclated with mobilization and transfer into the water first of manganese and later of iron. There is a concurrent transfer into the water of substantial quantities of phosphate, previously held in complex form, which may have important biological consequences. Other changes include libcration into the water of ammonia and silicate. Further reduction of the water-sediment system permits microbial reduction of sulfate. A third example of sediment-water exchange occurs during winter stratification under ice cover. In Tornetrask, in the course of 95 days of ice cover, a relatively thin layer of bottom water, initially at lC, gained heat and bicarbonate from and lost oxygen to the sediments. The density increase, arising from the heat gain, set density currents in motion that drained this contact water into the deepest parts of topographically isolated subbasins.

Speech perception and phonemic restorations

Abstract: When a speech sound in a sentence is replaced completely by an extraneous sound (such as a cough or tone), the listene restores the missing sound on the bases of both prior and subsequent context. This illusory effect, called phonemic restoration (PhR), causes the physically absent phoneme to seem as real as the speech sounds which are present. The extraneous sound seems to occur along with other phonemes without interfering with their clarity. But if a silent gap (rather than an extraneous sound) replaces the same phoneme, the interruption in the sentence is more readily localized in its true position and PhRs occours less frequently. Quantitative measures were taken both of the incidence of PhRs and of the direction and extent of temporal mislocalizations of interruptions for several related stimuli under a variety of experimental conditions. The results were connected with other auditory illusions and temporal confusions reported in the literature, and suggestions were made concerning mechanisms employed normally for verbal organization.

The relative effectiveness of some common graduated point symbols in the presentation of quantitative data

Abstract: Circles with their areas varying in direct proportion to quantities represented are a common form of graduated point symbols. When so used, unfortunately, the average map reader perceives a smaller quantitative difference than intended because circle size differences are usually underestimated. An apparent size scale developed empirically fifteen years ago is claimed to eliminate the problem of consistent underestimation. More recent investigations by psychologists and cartographers support the apparent size scale. Bars communicate quantitative variation effectively when graduated in the traditional manner on a linear basis, but wedges require an apparent size scale and even then are less accurately judged. Les cercles dont la surface varie en proportion directe de la quantite a representer constituent une forme habituelle de symbole quantitatif. Leur utilisation a cette fin, malheureusement, a pour resultat que le lecteur de la carte percoit souvent une difference quantitative moindre que celle que l'on ...

Synthesis and Properties of Polyphenyls and Polyphenylenes

Abstract: Numerous reactions have been developed over the years which lead to products containing coupled aromatic nuclei. These methods involve many different types of starting materials as well as a variety of mechanisms. Earlier work was concerned mainly with the lower members of the biphenyl series, but the increasing demand for thermally stable materials has resulted in the development of numerous methods for preparation of the higher molecular weight polyphenyls or poly(phenylene)s. Indeed, research into the preparation and properties of these materials has expanded at a remarkable rate during the last decade and is emphasized by the fact that almost 50% of the references cited herein are the results of work carried out since the last major review on this subject was published in 1960 [1]. Less comprehensive reviews [2–4] have since appeared.

Effects of Temperature on Electrolyte Balance and Osmoregulation in the Alewife (Alosa pseudoharengus) in Fresh and Sea Water

Abstract: A study of the effects of temperature and salinity on ionoregulation in the alewife, Alosa pseudoharengus, revealed that concentrations of sodium, potassium, and calcium in plasma and muscle were similar in fish adapted to fresh water and those adapted to sea water. The non-stressed alewife is apparently an excellent ionoregulator in both environments. Acute exposure to cold caused a shift in plasma concentrations of sodium and calcium toward environmental concentrations, i.e., these ions decreased in fresh water and increased in sea water. An ionoregulatory failure due to cold is suggested. High temperatures had little effect on plasma electrolyte levels in fresh water whereas in sea water the concentrations of sodium, potassium, and calcium were elevated. Mortalities of the alewife in the Great Lakes may be caused by osmoregulatory failure induced by acute exposure to cold, but are probably not induced by exposure to elevated temperatures. Fish thermally acclimated in the laboratory or in Lake ...

Elimination methods in the m × n sequencing problem

Abstract: This paper considers elimination methods in solving the sequencing problem where no passing is permitted. An elimination method consists of reducing (according to some criterion) the initial set of n solutions to a smaller set. A crucial question arises as to whether this reduced set contains an optimal solution. The answer is affirmative if this elimination criterion implies condition (3).

The Transportation Paradox.

Abstract: : A paradox arises when a transportation problem admits of a total cost solution which is lower than the optimum and is attainable by shipping larger quantities if goods over the same routes that were previously designated as optimal. That is, falling total costs are present in moving to the greater shipment quantities. Necessary conditions for this to occur are established and an algorithm for solving this expanded transportation problem is supplied. (Author)

Application of the Cooper Twelve-Minute Run-Walk Test to Young Males

Abstract: The study was designed to establish norms for the Cooper 12-minute run-walk test applicable to young males. Eighty boys, 11 through 14 years of age, served as subjects. The mean distance covered by the 11- and 12-year-olds during the 12-minute run-walk was 2,308 yards. The mean distance covered by the 13- and 14-year-olds was 2,507 yards. The difference between the two groups was statistically significant (P<.01). The test-retest reliability coefficient for the test on a subsample was .92. Maximal aerobic capacity was also measured with a subsample of 17 subjects to determine the relationship between aerobic capacity and run-walk performance. The correlation coefficient between aerobic capacity and run-walk performance was .65. While the correlation was statistically significant (P<.01), caution is advised in attempting to predict aerobic capacity from run-walk performance with young urban subjects.

Identification times for phonemic components of graded complexity and for spelling of speech

Abstract: Identification time was measured for targets in speech in terms of the number of phonemes occurring between the target and response. Auditory targets in the mam experiment were at three levels of phonetic complexity; (1) monosyllabic words or nonsense syllables, each containing four phonemes; (2) clusters (vowel + consonant) consisting of the second and third phonemes within these syllables; (3) individual phonemes within these clusters. Identification time was always shorter for (1) than for (2) or (3). The effect of semantic and grammatical context upon identification was small. Plosive consonants which did not begin a syllable generally could not be identified as isolated phonemic targets, although they could be identified readily as part of a cluster. Letter targets corresponding to the spelling of the auditory stimulus permitted identification of plosive consonants, and in general followed different rules than the phonemic targets. Additional observations concerning individual targets were made.

On the Elastic and Thermodynamic Properties of Transition Metal Carbides

Abstract: Values of the Debye temperature,θE, for a number of refractory carbides were calculated from elastic constant data and then compared with those of the Debye temperature,θD, as derived from low-temperatureCP data. It is found that an apparent discrepancy existed in the literature between the values ofθE andθD for these carbides. However, when the same units are used, agreement of 10 pct or better between the values ofθE andθD is found for all the carbides with the exception of MoC1/2. A discrepancy of 10 pct is reasonable based on an analysis of both the experimental and theoretical difficulties associated with the evaluation ofθE and θD for this class of materials. All the elastic constant data used were taken from the literature. Values ofCP for TiC, HfC, and WC were measured in the present study from 1.5° to 15°K. These values in addition to the literature data were used in derivingθD values. A correlation of the bulk modulus with interatomic spacing is presented for these refractory carbides. Based on this correlation, the bonding forces responsible for the cohesion of this class of materials are discussed.

Operant Conditioning in the Classroom Setting: A Review of the Research

Abstract: The purposes of this review were (a) to summarize the research following an applied behavioral analysis which has relevance for public school classrooms and (b) to discuss the problems and important considerations involved in an applied behavioral analysis of classroom behavior. Studies in this area are grouped into the following categories according to the nature of the reinforcement employed and assessed: (a) teacher attention, (b) peer attention, (c) token reinforcement, and (d) vicarious reinforcement. The problems of obtaining teacher cooperation, valid and reliable measurements, and confirmation of stimulus control through design of the experiment were discussed. Finally, the implications of these studies for classroom behavior control, as well as for future research, were explored

Finding a Single Defective in Binomial Group-Testing

Abstract: The problem of finding a single defective item from an infinite binomial population is considered when group-testing is possible, i.e., when we can test any number of units x simultaneously and find out in one test if all x are good or if at least one of the x is defective. An optimal procedure is obtained in the sense that it minimizes the expected number of tests required to find one defective. Upper and lower bounds are derived using information theory and the relation of our procedure to the Huffman algorithm and the corresponding cost is studied.

Water thievery in a rice irrigation system in taiwan

Abstract: Water thefts and conflicts are more common in some irrigation systems, or in some parts of a single irrigation system, than in others. Water thievery in the Nan-hung canal system in Taiwan is analyzed through an examination of the need to steal, the opportunities to steal, farmer awareness of opportunities to steal, and farmer willingness to steal. Water supply, water rights customs, water control methods, the location of houses, and the size of the system influence the number and distribution of thefts and conflicts.

Achievement, sociability, and task importance in relation to academic cheating.

Abstract: The present study examined the relation of self-report data and cheating behavior. An unobtrusive measure was devised and subsequent data suggest that selection of a cheating measure has important implications for research on cheating. Ss were 27 members of an advanced Navy ROTC class at a large midwestern university. Ss completed a questionnaire consisting of 15 items relating to academic activity, social participation and future plans, selected from a more extensive questionnaire employed by Bowers (1964). The officer teaching the class introduced the questionnaire as part of a nationwide study of ROTC groups. Three weeks later, E administered a difficult test calling for novel solutions to problems. Ss were instructed that their scores were predictive of officer success. When Ss had completed the test they were allowed to see the correct answers \"for their own information.\" Cheating was assessed with a specially constructed answer sheet unit. The top sheet was a standard, multiple-choice answer sheet which was removable from the rest of the unit. The correct answers to the questions, permanently bound to a cardboard backing, were under the top sheet. Berween the correct answers and the backing were two carbon treated sheets which duplicated Ss' original answers. Cheating was identified by noting discrepancies between the response sheet S turned in after seeing the correct answers, and the record of his responses on the treated paper. One-third of the 27 Ss cheated. Achievement variables do not seem to be as important as some investigators (Bowers, 1964) have reported, when cheating is measured unobtrusively. Cheaters were not significantly different from noncheaters on grade point average or test scores. It was correctly hypothesized on the basis of previous research (Bowers, 1964; Bonjean & McGee, 1965) that cheaters would show greater social participation. Cheaters in the present study belonged to more clubs per man (x? = 6.75, p < .05, 1 d f ) and held more leadership positions (x2 = 6.0, p < .05, 1 df) than noncheaters. In relation to task importance, candidates who intended to be career officers and for whom the test was presumably more important, were more often cheaters than Ss who did not intend to be career officers (x ' = 11.21, p < .001, 1 df) .

The Public, The Media, and the Knowledge Gap

Abstract: (1971). The Public, The Media, and the Knowledge Gap. Environmental Education: Vol. 2, No. 4, pp. 3-8.

Test for the Comparison of Two Exponential Distributions

Abstract: Let X (1), …, X (k) be the first k ordered observations of a sample of size m from the distribution with p.d.f. f(x; β1, θ) = (1/θ) exp [-(x – β1)/θ] for x ≥ β1 ≥ 0, θ > 0 and zero elsewhere (2 ≤ k ≤ m); let Y (i), …, Y (l) be the first l ordered observations of a sample of size n from the distribution with p.d.f. g(y; β2, θ) = (1/θ) exp [—(y – β2)/θ] for y ≥ β2 ≥ 0, θ > 0 and zero elsewhere (2 ≤ l ≤ n). It is assumed that θ is unknown. A test based on (X (1), …, X (k), Y (1), …, Y (l)) is proposed for the null hypothesis β1 = β2 against the alternative β1 ≠ β2. The distribution of the test statistic under the null hypothesis is derived. The significance points for various values of k, I, m, n are tabulated for (α = .05 and .Ol.

On the Order of Solutions of Analytic Linear Differential Equations

Abstract: (1) d/dxX(z) = A{z)X{z), where X(z) is an n x 1 column vector and A(z) is an n x n matrix of singlevalued meromorphic functions in a neighbourhood of the (isolated) singular point 0. Sometimes we write A instead of A(z) but we always consider a matrix of functions with such a notation unless explicitly stated otherwise. Each fundamental solution matrix for (1) can be represented near zero as (2) 0(s) = 8(z)z*, where S(z) is an n x n matrix of single-valued analytic functions in some deleted neighbourhood of the origin and R is an n x n constant matrix (called the monodromy matrix) which displays the multivaluedness of the fundamental set of solutions as they are analytically continued about the origin. (See [1] 108-9.) In order to study the growth of solutions near zero, we define the norm of a matrix as the sum of the moduli of its components. Since z consists of finite sums of products of powers of z and logz, and if we make z remain in some sector of fixed angle as \\z\\ -> 0, then \\\\z\\\\ = Odzl\"\") for some real number r ([1] 113). The more interesting factor in terms of growth is \\\\S(z) ||. There are two cases which can arise. The first is the classically discussed case of the regular singular point in which (3) \\\\S(z)\\\\ = 0(\\z\\-z) as |*|->0

Minimum Weight Design of Light Gage Steel Members

Abstract: Light gage steel is used extensively in light construction components. Large tonnages of a standard design are commonly produced, thus the minimum material requirements are of utmost importance to the product designer. A technique is presented for designing a minimum weight member to support a given loading condition. The problem is treated as a numerical optimization problem in which the variables are the dimensions and thickness of a given type of cross-sectional shape. Design requirements are based on the American Iron and Steel Institute Specification for the Design of Cold-Formed Steel Structural Members, 1968 Edition. These requirements are used to calculate a minimum acceptable thickness for a section whose other dimensions are considered temporarily fixed. This establishes the minimum weight design for the particular set of dimensions. Search methods are then employed to systematically establish sets of dimensions yielding reduced weight sections. Both a direct search and gradient search were examined and the latter found to be more efficient.

Cranial suture closure in two species of South American monkeys

Abstract: Cranial suture closure is examined in two species of South American monkeys, Saimiri sciureus and Saguinus nigricollis. Sequences in closure were sought as indicators of skeletal age. Some sutures seem to be more reliable determinants of skeletal age than others, and these sutures and their sequence of closure are different in the two species examined. The sphenooccipital synchondrosis and the palatal portion of the Interpremaxillary suture show regular fusion associated with age in both species. In Saimiri the maxillopremaxillary sutures are also reliable indicators of age, whereas they are not in Saguinus; however, in the latter the presphenoid-postsphenoid synchondrosis closes regularly whereas it does not in Saimiri. In Saimiri the predictable sequence is (1) maxillo-premaxillary, (2) transverse maxillo-premaxillary, (3) spheno-occipital, (4) interpremaxillary. In Saguinus it is (1) presphenoid-postsphenoid, (2) spheno-occipital, (3) interpremaxillary. It is possible that the sequences of suture closure and the variability in this process may indicate genetic and taxonomic relationships.