Showing papers by "University of Texas at Arlington published in 1983"

The effects of new science curricula on student performance

Abstract: This study summarizes the results of a quantitative synthesis of the retrievable primary research dealing with the effects of new science curricula on student performance. This study synthesizes the results of 105 experimental studies involving more than 45,000 students and utilizes the quantitative synthesis perspective to research integration known as meta-analysis (Glass, 1976). A total of 27 different new science curricula involving one or more measures of student performance are included in this meta-analysis. Data were collected for 18 a priori selected student performance measures. The results of this meta-analysis reveal definite positive patterns of student performance in new science curricula. Across all new science curricula analyzed, students exposed to new science curricula performed better than students in traditional courses in general achievement, analytic skills, process skills, and related skills (reading, mathematics, social studies and communication), as well as developing a more positive attitude toward science. On a composite basis, the average student in new science curricula exceeded the performance of 63% of the students in traditional science courses.

Positronium Formation in Collisions of Positrons with He, Ar, and H 2

Abstract: Absolute cross sections for the formation of positronium in positron collisions with He, Ar, and ${\mathrm{H}}_{2}$ have been measured for incident positron energies up to 76.3 eV. The results are markedly different, in magnitude and energy dependence, from those of Charlton et al. The measurements in He and ${\mathrm{H}}_{2}$ agree well with distorted-wave and charge-exchange calculations.

Comparisons of self‐efficacy and expectancy models of occupational preferences for college males and females

Abstract: Expectancy models have related individual work values and the availability of desired rewards in different occupations to occupational preferences, while self-efficacy models have stressed personal perceptions of individual capacities to perform in different occupations to occupational preferences. This study demonstrates support for both models, and indicates that these models have separate and independent relationships to occupational preference. Further analysis supports the contention that the perceptions of self-efficacy may be an important factor in explaining sex differences in occupational preferences.

Microbial activities in the emitted hydrothermal waters of the Galápagos rift vents

Abstract: In-situ measurement of chemolithotrophic and some heterotrophic microbial activities were made in the immediate vicinity of actively discharging hydrothermal vents of the Galapagos Rift region at depths of 2 500 to 2 600 m. The CO2-assimilation or chemosynthesis productivity in the emitted vent waters, freshly mixed with oxygenated ambient seawater of 2°C, was minor compared to the bacterial biomass produced within the subsurface vent system prior to emission. Uptake of acetate and glucose indicated the presence of mixotrophic or facultatively chemolithotrophic bacteria in the emitted vent waters in agreement with isolations. Demonstration of ribulose bisphosphate carboxylase and phosphoenol pyruvate carboxylase in cultures of thiobacilli isolated from these vent water supports the notion that chemoautotrophic sulfur-oxidizing bacteria are one of the sources of primary production in the form of particulate organic carbon for filtering organisms in the deep sea hydrothermal environment. The rates of bacterial metabolic activities in emitted vent water are too low for the amount of invertebrate biomass and the rate of its growth and maintenance. Therefore, the larger portion of chemosynthetic sustenance of deep sea vent ecosystems appears to be based on symbiotic associations between bacteria and invertebrates and on surface attached bacteria.

The effect of temporal environmental heterogeneity on community structure: a replicated experimental study.

Abstract: Periodicity, predictability and stochasticity of environmental perturbations are shown to influence the community structure that develops in microcosms. Sets of replicate, microalgal communities were subjected to different temporal patterns of rarefaction and resource resupply and their species-abundance patterns after 120 days of such manipulations were determined. Perturbations having, 1, 7, and 28 day periodicities differentially effected community structure. The predictability of these perturbations had a less profound influence on the communities which developed than the average perturbation periodicity.

Chrysophycean cysts: indicators of eutrophication in the recent sediments of Frains Lake, Michigan, U.S.A.

Abstract: The recent sediments of Frains Lake, Michigan contain a rich and well preserved association of chrysophycean cysts. Forty one forms are revealed by scanning electron microscopy (SEM) and light microscopy (LM). Taxonomic descriptions. and SEM micrographs are provided for the dominant forms. The three dominant taxa throughout the sediments, Cysta minima, C. modica and C. subbavaricum, do not show significant shifts in proportional abundance associated with European settlement and the onset of cultural eutrophication. However, certain subdominant taxa do show clear trends. Density counts indicate a dramatic decline in cyst concentration (by volume and by dry mass) and a sharp increase in absolute accumulation (net annual influx) following settlement. The Frains Lake profile of chrysophycean cysts is compared to sequences of other North American and European temperate lakes. The utility of chrysophycean cysts as paleoenvironmental indicators is considered on the basis of these results.

Paths to the City: Regional Migration in Nineteenth-Century France

Abstract: Paths to the City presents a study of migration from rural areas to the industrializing city of Nimes in the 19th century. With unusual technical skill, Moch is able to reconstruct the lives of migrants in their villages and in the cities. She is able to separate them into separate streams of migrations; trace the work, marriage, and child-bearing patterns of migrants back to their rural roots; and compare migrants with people who did not move. She is also able to augment the demographic patterns she outlines with portraits of what happened to real individual people.

A Multiple Beam Synthetic Aperture Radar Design Concept for Geoscience Applications

Abstract: The multiple beam synthetic aperture radar (SAR) has been presented as a superior alternative to conventional side-looking SAR designs for mapping earth resources from space. The multiple beam approach provides wide swath coverage at nearly constant incident angle while conserving peak power. These desirable system characteristics, however, are realized at the expense of additional signal processing. A design example illustrates the attributes of the multiple beam SAR in comparison to a conventional side-looking system. A novel beam formation processing architecture is shown which can provide simultaneous range compression while forming the beams. A configuration for the image formation processor is proposed and analyzed in terms of an analog implementation which can perform Doppler compression at speeds faster than real time. These implementation schemes indicate that on-board processing for the multiple beam SAR is possible.

A Note on Pooling Variances

Abstract: The estimation of variance in the normal distribution is studied under statistical inference based on conditional specification. When there are two samples available for estimating the variance and it is not certain whether the two samples are from the same population, the experimenter usually uses a test to resolve the uncertainty. When the test is not significant, the samples are pooled to obtain a pooled estimator; otherwise, the individual sample variance is used. The bias and mean squared error of such a preliminary test estimator are studied. It is shown that the preliminary test estimator has a smaller mean squared error than the usual unbiased estimator when the level of significance for the preliminary test is appropriately chosen.

Effects of Age, Race, Sex, and Employment Experience on Students' Perceptions of Job Applications:

Abstract: Although a number of laws exist concerning equal employment opportunity (EEO), research suggests that discrimination still exists. Are attitudes and intentions regarding EEO compliance evolving among those who are planning managerial careers and have grown up in the era since passage of the Civil Rights Act of 1964? To explore this question, the present study investigated business students' evaluations of various job applications. Specifically, students were exposed to resumes of job applicants who varied in terms of their employment experience, age, race, and sex. Analyses indicated a main effect for employment experience and two small interactions. The relationship of these perceptions to actual future behaviors was discussed. Results were also compared to those of previous studies of business students' attitudes and intentions regarding discrimination in employment.

Morphological variability in populations of chrysophycean resting cysts. i. genetic (interclonal) and encystment temperature effects on morphology1

Abstract: Many chrysophycean species produce resting cysts (statospores) with purportedly species-specific morphology. I investigated variation in the cyst morphology of a single species that may result from genetic differences among the vegetative clones involved and from variation in the temperature of the environment during cyst development. Populations of Dinobryon cylindricum Imhof cysts were produced under defined conditions in vitro and then sampled for morphological analysis based on SEM micrographs. Morphological data is presented and then used in a multivariate discriminant analysis to determine the utility of each morphological character in distinguishing the six populations studied. Results suggest that some features of cyst morphology (i.e. cyst diameter) are invariant among the populations, while other features show distinctive variation. The density of spines covering the cyst body as well as the morphology of those spines appear correlated to the specific clones involved, and thus may represent useful phenotypic genetic markers. The length and definition of both the spines and the cyst collar, on the other hand, are markedly influenced by encystment temperature. The implications of these findings for paleoecological studies is discussed.

Ammonium-Nitrogen in Green River Formation Oil Shale

Abstract: It has been assumed that all of the nitrogen in oil shale from the Green River Formation is present as organic nitrogen and that the nitrogen in spent shale from retorting is present in the char or coke. In fact, from 41 to 84 percent of the nitrogen is present as ammonium fixed within silicate minerals in five samples of raw oil shale and between 46 and 69 percent of the nitrogen is similarly fixed in two samples of spent shale. Both organic nitrogen and fixed ammonium-nitrogen are lost during retorting by the Fischer assay procedure; the loss of organic nitrogen is greater.

Crowding in Jails

Abstract: The effect of housing density was examined in three different jails. High levels of density were associated with various negative psychological reactions. Social density (number of people in a housing unit) was a more important predictor of these effects than spatial density (space per person). Housing type did not affect illness complaint rate but some evidence was obtained for elevated blood pressure in highly dense housing when inmates were confined for large parts of the day. These results were related to previous research on crowding in prisons and other environments.

Pupil dilations following pairs of identical and related to-be-remembered words.

Abstract: Two experiments are reported in which the spacing between pairs of identical (Experiment 1) or pairs of related (Experiment 2) to-be-remembered words were varied while pupil diameter and frequency judgments were measured. In Experiment 1, frequency judgments increased with increases in spacing length. In Experiment 2, frequency judgments decreased with increases in spacing length. In both experiments, however, pupil dilations increased with increases in spacing length. These results are interpreted as supporting theories that argue that massed repetitions require less processing than spaced repetitions. It is argued that this deficiency in processing reduces retention of massed repetitions of identical words. For massed presentation of related words, organizational strategies can be used with little effort to increase retention.

C -matrix transform

Abstract: An approximation to the discrete cosine transform (DCT), called the C-matrix transform (CMT), has been developed by Jones et al. [3] for N = 8. This is extended to N = 16 and 32 and its performance is compared with the DCT based on some standard criteria. CMT is computationally simpler as it involves only integer arithmetic. It has potential in signal processing applications because of its closeness to the DCT.

Heat Transfer Coefficient in Ducts With Constant Wall Temperature

Abstract: An analytical method for the numerical calculation of the heat transfer coefficient in arbitrarily shaped ducts with constant wall temperature at the boundary is presented The flow is considered to be laminar and fully developed, both thermally and hydrodynamically The method presented herein makes use of Galerkin-type functions for computation of the Nusselt number This method is applied to circular pipes and ducts with rectangular, isosceles triangular, and right triangular cross sections A three-term or even a two-term solution yields accurate solutions for circular ducts The situation is similar for right triangular ducts with two equal sides However, for narrower ducts, a larger number of terms must be used

Chapter 5: Nonverbal Communication in Teaching

Abstract: Research in many settings outside the classroom has indicated that nonverbal communication can serve a wide range of functions in human interaction. These include: (1) supplementing, reinforcing, or regulating verbal exchanges (Ekman & Friesen, 1969); (2) revealing emotional states or personality traits (Ekman & Friesen, 1975; Exline, Ellyson, & Long, 1975; Scherer, 1974); (3) providing cues for impression formation (Imada & Hakel, 1977; Wexley, Fugita, & Malone, 1975); (4) indicating liking or disliking for individuals, situations, or ideas (Mehrabian, 1972); (5) communicating relative status of interactants (Henley, 1977; Mehrabian, 1972); (6) being persuasive (Albert & Dabbs, 1970; McGinley, LeFevre, & McGinley, 1975); and (7) influencing the performance of others (Imada & Hakel, 1977; Word, Zanna, & Cooper, 1974). (A more complete discussion of the many possible functions of nonverbal behavior can be found in LaFrance & Mayo, 1978.) It is likely that nonverbal communication functions similarly in the classroom. In fact, many educators have presented cogent arguments for the importance of nonverbal communication in teaching (e.g., Beebe, 1981; Galloway, 1972; Grant & Hennings, 1971; Richey & Richey, 1978; Wolfgang, 1977). However, until quite recently, educational researchers have neglected the systematic study of this topic. The research that has been carried out consists predominantly of scattered, isolated studies without a common theoretical basis. This lack of internal coherence in previous research on nonverbal communication in teaching probably has been