Showing papers by "Northern Illinois University published in 1989"

RNA catalytic properties of the minimum (-)sTRSV sequence.

Abstract: We have identified an RNA catalytic domain within the sequence of the 359 base long negative-strand satellite RNA of tobacco ringspot virus. The catalytic domain contains two minimal sequences of satellite RNA, a 50-base catalytic RNA sequence, and a 14-base substrate RNA sequence. The catalytic complex of catalytic RNA/substrate RNA represents a structure not previously found in any RNA catalytic reaction described to date. The reaction is truly catalytic since the catalytic RNA has multiple substrate cleavage events and is not consumed during the course of the reaction. A linear relationship is seen between reaction rate and catalytic RNA concentration. The reaction has a Km of 0.03 microM, a kcat of 2.1/min, a temperature optimum of near 37 degrees C, and an energy of activation of 19 kcal/mol.

Assessing age and gender differences in perceived risk and fear of crime

Abstract: Much of the research on fear of crime indicates that women and older persons are highly afraid of crime. These findings, especially older persons' fear of crime, are widely communicated in the scientific and popular media. This study examines age and gender differences in perceived risk and fear of crime. The data are from telephone interviews of 320 randomly selected residents in a southeastern metropolitan area of the United States. The relationships of age and gender to fear of crime are compared using a National Crime Survey (NCS) measure of fear of crime and 11 alternative indicators of fear of specific offenses. Women reported signifcantly greater perceived risk and fear of crime than men regardless of how fear of crime was measured and older adults reported the greatest fear of crime when the NCS measure was used. but not when the alternative individual measures of fear of crime were used. A LISREL model with latent constructs for fear of personal crime and fear of property crime also indicates that older adults do not have higher levels of fear of crime. In short, the extent of fear in the everyday lives of most older persons has been overestimated in many previous studies because of measurement problems.

Cooperative Teaching A Model for General and Special Education Integration

Abstract: A variety of social and educational forces are resulting in significant changes in the traditionally dichotomous relationship between general and special education. One service delivery model that may be especially useful for reducing the gap between the two delivery systems is cooperative teaching, in which general and special educators work in a systematic and coordinated fashion in educationally integrated settings. This article describes cooperative teaching and outlines various arrangements through which it might be implemented.

Proof frames of preservice elementary teachers

Abstract: This study asked 101 preservice elementary teachers enrolled in a sophomore-level mathematics course to judge the mathematical correctness of inductive and deductive verifications of either a familiar or an unfamiliar statement. For each statement, more than half the students accepted an inductive argument as a valid mathematical proof. More than 60% accepted a correct deductive argument as a valid mathematical proof; 38% and 52% accepted an incorrect deductive argument as being mathematically correct for the familiar and unfamiliar statements, respectively. Over a third of the students simultaneously accepted an inductive and a correct deductive argument as being mathematically valid. The concept of proof is of great importance in the study of mathematics. Smith and Henderson (1959) stated, for example, that "the idea of proof is one of the pivotal ideas in mathematics. It enables us to test the implication of ideas, thus establishing the relationship of the ideas and leading to the discovery of new knowledge" (p. 178). Research has explored this important topic with elementary and high school students (Bell, 1976, 1979; Galbraith, 1981; Lester, 1975; Williams, 1980). Two studies are most pertinent to our research. Fischbein and Kedem (1982) investigated whether high school students understand that mathematical proof requires no further empirical verification. They verified empirically their assumption that "students, after finding or learning a correct proof for a certain mathematical statement, will continue to consider that surprises are still possible, that further checks are desirable in order to render the respective statement more trustworthy" (p. 128). Vinner (1983) focused on the question, What makes a given sequence of correct mathematical arguments a mathematical proof in the eyes of high school students? He asked students to give their preference for proving a particular case of a previously proved statement. He found they preferred using a particularization of the deductive proof rather than the general result. The general proof was viewed as a method to examine and to verify a particular case. Vinner further observed that students judged a mathematical proof on its appearance, relying on ritualistic aspects of proof. In this study, we investigated the views of proof of a different population, preservice elementary school teachers. Further, we investigated a different aspect of proof, one related to inductive and deductive reasoning. The views of proof held by preservice elementary school teachers are important. Because proof receives very limited attention in the elementary school curriculum, the main source of children's experience with verification and proof is the classroom teacher. Classroom teachers' understanding of what constitutes mathematical proof is important, even though they do not directly teach that topic. If teachers lead their students to believe that a few well-chosen examples constitute proof,

The genetics of phenotypic plasticity I. Heritability

Abstract: Methods for estimating the genetic component of phenotypic plasticity are presented. In the general case of clonal replicates or full-sibs raised in several environments, the heritability of plasticity can be measured as the ratio of the genotype-environment interaction variance to the total phenotypic variance. In the special case of only two environments plasticity also can be measured as the difference among environments in genotype or family means. In that case, the heritability of plasticity can be measured as either a ratio of variance components or as the slope of a parent-offspring regression. The general measure suffers because no least-square standard errors have been developed, although they can be calculated by maximum-likelihood or bootstrapping techniques. For the other two methods least-square standard errors can be calculated but require very large experiments for statistical significance to be achieved. The heritability measures are compared using data on plasticity of thorax size in response to temperature in Drosophila melanogaster. The heritability estimates are all in close agreement. Models of the evolution of phenotypic plasticity have treated it as a trait in its own right and as a cross-environment genetic correlation. Although the first approach is the one used here, neither one is preferred.

Structural position and violence: developing a cultural explanation*

Abstract: Research assessing the capacity of a cultural explanation to account for the relationship between certain structural positions and high rates of criminal violence has ignored a significant intervening variable. That variable is disputatiousness—the likelihood of being offended by a negative outcome and seeking reparation through protest. This article develops a cultural model of disputatiousness and aggressiveness. It hypothesizes that individuals who occupy positions featuring high rates of violence are more likely than their counterparts to be offended by a negative outcome, to protest the injury, and to use force when the protest fails. It also hypothesizes that differential disputatiousness and aggressiveness are most pronounced when the negative outcome involves an attack on the self by an equal in a public setting. Testing these hypotheses calls for individual level data bearing on behavioral dispositions under a variety of circumstances. A methodological procedure for collecting such data is proposed, and suggestions for future research are discussed.

RNA catalyst for cleaving specific RNA sequences

Abstract: A synthetic RNA catalyst capable of cleaving an RNA substrate, the catalyst comprising a substrate binding portion and a "hairpin" portion. The invention also provides an engineered DNA molecule and a vector, each comprising a DNA sequence coding for an RNA catalyst according to the invention. The invention further comprises host cells transformed with the vectors of the invention which are capable of expressing the RNA substrate. Finally, the invention provides a method of cleaving an RNA substrate which comprises contacting the substrate with a synthetic RNA catalyst according to the invention.

Detection of an oxyferryl porphyrin pi-cation-radical intermediate in the reaction between hydrogen peroxide and a mutant yeast cytochrome c peroxidase. Evidence for tryptophan-191 involvement in the radical site of compound I.

Abstract: Peroxide oxidation of a mutant cytochrome c peroxidase, in which Trp-191 has been replaced by Phe through site-directed mutagenesis, produces an oxidized intermediate whose stable UV/visible absorption spectrum is very similar to that of compound I of the native yeast enzyme. This spectrum is characteristic of an oxyferryl, Fe(IV), heme. Stopped-flow studies reveal that the reaction between the mutant enzyme and hydrogen peroxide is biphasic with the transient formation of an intermediate whose absorption spectrum is quite distinct from that of either the native ferric enzyme or the final product. Rapid spectral scanning of the intermediate provides a spectrum characteristic of an oxyferryl porphyrin pi-cation-radical species. At pH 6, 100 mM ionic strength, and 25 degrees C, the rate constant for formation of the oxyferryl pi-cation radical has a lower limit of 6 X 10(7) M-1 s-1 and the rate of conversion of the transient intermediate to the final oxidized product is 51 +/- 4 s-1. Evidence is presented indicating that Trp-191 either is the site of the radical in CcP compound I or is intimately involved in formation of the radical.

A structural model of first-grade outcomes for an urban, low socioeconomic status, minority population.

Abstract: This study tested a social context, longitudinal model of the early schooling process on three first-grade outcomes for 1,539 ethnic minority children (1,470 were Black and 69 were Hispanic)

Distribution and Abundance of Small Mammals along an Elevational Transect in Temperate Rainforests of Chile

Abstract: Assemblages of small mammals in temperate Andean rainforests of southern South America are diverse but poorly known. Herein, we describe an elevational transect through temperate rainforests in Valle de La Picada, Chile, during February and March, 1984. The transect consisted of standardized removal trapping (165 traps set in lines at ca. 7-m intervals and operated for 6 consecutive days) at each of seven elevations: 425 m, 505 m, 620 m, 715 m, 820 m, 920 m, and 1,135 m. A total of 514 small mammals representing two species of marsupials and seven species of sigmodontine rodents was collected. Trap success averaged 7.4% across traps, days, and elevations. Number of captures by individual traps during the sample period was indistinguishable from a Poisson distribution, both throughout the transect and at individual levels, suggesting independence of captures among traps. Captures were biased significantly by trap type, with museum specials securing significantly more Dromiciops australis and all forms of Akodon than Sherman live traps; the same biases were suggested by captures of Irenomys tarsalis and Auliscomys micropus . As expected, total number of individuals taken at each elevation declined throughout the sampling period while the cumulative number of species rose. Number of species, number of individuals, and species diversity varied inversely with elevation. Number of species and species diversity taken each day reached a maximum after 2–4 days of sampling. Captures of Rhyncholestes raphanurus, Akodon sanborni , putative hybrids of A. sanborni and Akodon longipilis , and I. tarsalis were correlated inversely with elevation. Conversely, D. australis, A. longipilis , and A. micropus were taken more commonly at higher elevations, whereas captures of Oryzomys longicaudatus, Akodon olivaceus , and Geoxus valdivianus appeared unrelated to elevation. Systematic sampling procedures are viewed as essential for describing fundamental patterns of abundance and distribution that can be compared with other studies.

The Development of Concepts and Strategies Used in Computational Estimation

Abstract: Twelve students at each of Grades 3, 5, 7, and 9 were individually given tasks that presented problems with solutions from hypothetical students, accompanied by questions requiring students to contrast and compare the solutions. These tasks were followed by open-response estimation problems. The older children understood better than the younger children what was asked but were uncomfortable with estimation processes and outcomes. Acceptance of multiple estimates and rounding-then-computing rather than computing-then-rounding were both slow to develop. Recognition of the need to compensate for rounding errors increased with grade level. Schooling factors such as emphasis on unique answers and instruction on rounding and computional procedures seemed to influence results. Careful development of foundational concepts is recommended to prevent learning computational estimation as a set of algorithmic rules.

Black Lynchings: The Power Threat Hypothesis Revisited

Abstract: Between 1889 and 1931 nearly 3,000 blacks were lynched in the American South. One of the few "theory driven" efforts to explain the lynching phenomenon has employed Blalock's "power threat hypothesis" as a framework, arguing that southern whites lynched blacks to retain political hegemony. This paper reexamines the empirical support for a power threat interpretation of southern lynchings and finds it wanting. It is shown that previous analyses have been plagued by a variety of conceptual and methodological weaknesses including: sensitivity to extremely influential cases; sample selection truncation; an inappropriate measure of lynching; and possible model misspecification. Our alternative analyses, including corrections for these problems, reveal no support for the power threat explanation for lynching. Historically, southern whites have exploited an impressive arsenal of discriminatory tactics to subordinate the black minority. Lynching was one of the most brutal of these tactics. According to an inventory compiled by the National Association for the Advancement of Colored People (NAACP), 3,290 people were lynched in the South between 1889 and 1931 (NAACP

Geologic and environmental aspects of surface cementation, north coast, Yucatan, Mexico

Abstract: The northernmost part of the fresh-water aquifer of Yucatan, Mexico, is confined near the coast by a thin, flat, nearly impermeable calcareous layer. The authors think it probable that this confining layer is now developing by a process of sedimentation and precipitation of pore-filling cement on and near the surface of older limestone at the landward margin of the swamp that extends virtually continuously along the north Yucatan coast. It is their interpretation that this CaCO{sub 3}-cemented layer, which is 0.5 to 1.4 m thick, developed in the zone of discharge of the fresh-water aquifer. The presence of {sup 14}C (6.0% {plus minus} 0.4% modern carbon in a sample of aquitard) supports the hypothesis that cementation is an ongoing process. Further support comes from the remarkable regularity between modern mean sea level and the elevation of the landward boundary between the confining zone and normal karst along 250 km of coast. Confinement of the aquifer produces an elevation of the piezometric surface to about 0.5 m above mean sea level and a concurrent depression of the fresh-water/salt-water interface to an estimated depth of about 18 m below mean sea level at the coast. Breaching of the confining layer, implicit inmore » some development schemes for the region, could dramatically decrease the thickness of the fresh-water lens, a valuable water resource. The mixing zone beneath the confined part of the aquifer is a chemically active volume that may be vigorously pumped by tides (as evidenced by increased salinity of ground water near the coast), thus making this zone a likely place for rock-water interaction including, perhaps, dolomite formation.« less

Structural behavior and chemical order of Fe in YBa2(Cu1 − xFex)3O7 + δ

Abstract: Neutron and Mossbauer effect measurements have been made as a function of Fe concentration in orthorhombic ( x = 0.01, 0.02) and tetragonal ( x ⩾ 0.05), YBa 2 (Cu 1 − x Fe x ) 3 O 7 + δ . A systematic Rietveld analysis of the neutron data for all concentrations shows that Fe principally occupies a site slightly displaced ( y , y , 0) from the Cul (0, 0, 0) site in order to approach tetrahedral coordination. Neutron data for the x = 0.05 compound at 10 K show no significant difference from those obtained at 297 K. Local ordering of oxygen about an Fe substituent is conducive to placement of a second Fe atom in an adjacent site leading to local aggregation into chains of various lengths. This clustering is reflected in the character of low temperature magnetic Mossbauer spectra and in specific heat measurements. The Mossbauer spectra yield the relative changes in oxygen configurations about Fe atoms as the Fe concentration changes.

Sex typing and gender ideology: two facets of the individual's gender psychology that go together.

Abstract: Three studies tested the hypothesis that gendered personality dispositions are related to gender attitudes and gender discriminatory behaviors. In Study 1, sex-typed individuals were more likely than androgynous, undifferentiated, and cross-sex-typed individuals to accept gender rules designating culturally appropriate behavior for men and women. In Study 2, sex-typed individuals were particularly likely to pay attention spontaneously to the sex of job applicants and then to devalue the interview performances of women. In Study 3, only sex-typed men tended to endorse sexist language. As expected, sex typing and gender ideology go together. This relation between two facets of the individual's gender psychology indicates that some sex role inventories may tap more than expressivity and instrumentality.

North Pacific Cold-Season Surface Cyclone Activity: 1975–1983

Abstract: An eight year sample of cold-season (1 October through 31 March) extratropical cyclones in the, Pacific Ocean basin is used to study central pressure changes and life cycle characteristics. We find that over 90% of the cyclones passing through the area of the Kuroshio Current intensify in this region. Corresponding percentages in excess of 60% extend from the Kuroshio, south of 45°N, eastward to 130°W. Mean 24-h central pressure falls of all cyclones exceed 9 mb through the entire basin west of 140°W in the latitude band 30° to 50°N. A statistical analysis of 24-h central pressure changes is performed on all cyclones within our domain. A frequency distribution of 1996 cases of 24-h maximum deepening reveals statistically significant departures from a Gaussian distribution, with the coefficient of skewness substantially negative. We also find similarly significant departures from normal in a frequency distribution of all 24-h central pressure changes, in spite of the fact that this distribution wo...

Postcranial Adaptation and Evolution in Lorisidae

Abstract: With the exception of leaping, lorises and galagos move in many similar ways although frequencies and styles differ. This peculiar locomotor distinction in two closely related subfamilies has profoundly altered their respective postcranial anatomies from their common ancestor. A comparison of postcranial adaptation in extant forms shows that lorises and galagos differ somewhat in forelimb mobility, but are more fundamentally disparate in hindlimb adaptation. Inferences concerning locomotor adaptation in the lorisid fossil record indicate a more generalized locomotor pattern which is more like that of extant cheirogaleids than either living galagos or lorises. Thus, vertical clinging and leaping in galagines and the slow-climbing and suspensory movements of lorisines appear to be evolutionarily recent innovations from a more generalized locomotor past.

A Comparison of Students with Learning Disabilities to Low Achieving and Higher Achieving Students on Three Dimensions of Social Competence

Abstract: Research continues to accumulate attesting to the fact that many children with learning disabilities are experiencing social difficulties in school. Nonetheless, it is also clear that achievement deficits, with or without the presence of a handicapping condition, are also related to social problems in the classroom. Several studies attempting to clarify the relative roles of handicapping condition and achievement in social adjustment have produced mixed results. The purpose of the present study was to clarify this issue further by examining the social differences between elementary school students with learning disabilities and other low achieving and higher achieving children on three social dimensions: sociometric status, behavior as rated by teachers, and self-ratings of social competence. The results indicated that the children with learning disabilities may be at higher risk socially than their low achieving and higher achieving peers. Variables that may account for these results are discussed as wel...

Federal District Judges and Presidential Power During the Postwar Era

Abstract: Analysis of nearly two hundred federal district court decisions in cases involving the exercise of presidential power during the postwar era reveals two very different models of judicial decision making. In cases concerning presidential control of foreign and military policy, judicial decision making appears to be dominated by the recognition of fixed rules. So clear are these rules of deference to the executive that identification of the policy-making area alone constitutes an excellent predictor of case outcomes. By contrast, the statistical importance of such predictor variables as presidential prestige and whether the judge was appointed by the same president as that whose powers are at issue in the case suggests much greater relativism in the judicial response when the president is challenged as a domestic policymaker. As far as the federal district courts are concerned, presidential power over foreign and military affairs may aptly be called "the power to command," while the executive's power in dom...

Cardiovascular and ventilatory responses during formalized T'ai Chi Chuan exercise.

Abstract: T'ai Chi Chuan (TCC) is a widely practiced Chinese martial art said to physically develop balance and coordination as well as enhance emotional and mental health. TCC consists of a series of postures combined into a sequential movement providing a smooth, continuous, low-intensity activity. The purpose of this study was to examine the ventilatory and cardiovascular responses to the Long Form of Yang's style TCC. In addition, the subjects' TCC responses were compared to their ventilatory and cardiovascular responses during cycle ergometry at an oxygen consumption (VO2) equivalent to the mean TCC VO2 Six experienced (M = 8.3 yrs) male TCC practitioners served as subjects with data collected during the Cloud Hand movement of the TCC exercise. Significantly (p < .05) lower responses for ventilatory frequency (Vf) (11.3 and 15.7 breaths min−1), ventilatory equivalent (VE!VO2) (23.47 and 27.41), and the ratio of dead space ventilation to tidal volume (VD!VT) (20 and 27%) were found in TCC in comparison...

Additional cross-validation of the Child Abuse Potential Inventory.

Abstract: Cross-validation data indicate the Child Abuse Potential Inventory has classification rates in the mid-80% to mid-90% range. These rates, however, are based on discriminant analyses, which provide optimal classification rates. The present study provides classification rates based on the standard scoring procedure developed for field use. Rates were determined for new samples of 61 physical child abusers, 117 comparison parents, and 64 nurturing parents

Regulation of tyrosinase mRNA levels in mouse melanoma cell clones by melanocyte-stimulating hormone and cyclic AMP.

Abstract: Mouse melanoma cells in culture respond to melanocyte-stimulating hormone (MSH) by demonstrating increased activity of tyrosinase, the rate-limiting enzyme for melanin synthesis. Because this stimulation is strictly dependent upon continued transcription and translation, we have carried out studies to determine if MSH increases the level of tyrosinase mRNA. The abundance of tyrosinase message levels in melanoma cells treated with either MSH or dibutyryl cAMP was determined by Northern blot analysis utilizing a 946 base pair mouse tyrosinase cDNA probe. The tyrosinase cDNA was isolated from a λgt11 expression library generated from mRNA isolated from theopylline-induced Cloudman melanoma cells. The abundance of tyrosinase mRNA was determined in an amelanotic cell clone (AM-7AS) and a melanotic cell clone (MEL-11AS). The melanotic cell line had five times as much tyrosinase activity and almost 10 times more tyrosinase mRNA than the amelanotic line. Tyrosinase activity and mRNA increased in both cell lines after MSH addition. The amelanotic line treated with MSH for three days showed a fivefold increase in tyrosinase activity and a twofold increase in tyrosinase mRNA. The melanotic cell line treated with MSH for three days showed a 3.7-fold increase in enzyme activity and an eightfold increase in the abundance of tyrosinase mRNA. Dibutyryl cAMP also stimulated tyrosinase activity and the accumulation of tyrosinase mRNA. The data suggest that MSH, acting through cAMP, promotes an accumulation of tyrosinase mRNA.

Parental physical abuse and sexual orientation in males.

Abstract: Because male homosexuals have usually been found to have poorer relationships with their fathers than male heterosexuals, and because children who are disappointments to their parents are more likely to be physically abused than other children, it was hypothesized that gays are more likely than heterosexual men to have been physically abused by parents. This hypothesis was tested comparing 17 gay male college students and 67 heterosexual male college students. Gay males were found to have been more abused during adolescence. Abuse was related to a history of childhood femininity, to having poor relationships with fathers, and to having engaged in gay sex during adolescence. A history of childhood femininity and engaging in gay sex may provoke parental abuse.

Estimation and interpolation of missing values of a stationary time series

Abstract: . A complete solution of the important problem of estimating (interpolating) the missing values of a stationary time series is obtained by decomposing it into a prediction plus regression problem. This makes it possible to estimate the missing values by finding the multistep-ahead predictors and using the existing computer packages for time series analysis. Such a solution is vital for the E step of the EM algorithm, and it is shown how this algorithm can be used to develop a simultaneous procedure for estimating the parameters and missing values of a time series.

A search for trade-offs among life history traits inDrosophila melanogaster

Abstract: Are there underlying developmental and physiological properties of organisms that can be used to build a general theory of life history evolution? Much of the theoretical work on the evolution of life histories is based on the premise of negative developmental and genetic correlations among life history traits. If negative correlations do not exist as a general rule then no general theory taking them into account is possible. Negative genetic correlations among life history traits can come about by antagonistic pleiotropy. One cause of antagonistic pleiotropy is cost allocation trade-offs. Since cost allocation trade-offs are due to underlying physiological constraints they are expected to be common to closely related groups. A second form of antagonistic pleiotropy is specialization of genotypes to different niches. This type of antagonistic pleiotropy is expected to be specific to each population. We looked for trade-offs in life history traits of longevity and fecundity inDrosophila melanogaster. We used a half-sib mating design and raised the offspring at two temperatures, 19°C and 25°C. Correlations between longevity and fecundity showed some evidence of antagonistic pleiotropy at high temperature with no evidence of any trade-offs at low temperature. Correlations of early and late fecundity traits did show evidence of cost allocation trade-offs at both temperatures. Antagonistic pleiotropy was also found for cross-environmental correlations of fecundity traits. We conclude that, although life history trade-offs can not be generally assumed, they are frequently found among functionally related traits. Thus, we provide guidelines for the development of general theories of life history evolution.

Exercise and health psychology: Emerging relationships*

Abstract: The increasing prominence of health psychology has been paralleled by developments in the study of the psychology of health-related exercise. Evidence has been amassed which supports the efficacy of regular physical activity in reducing the risks of some debilitating health conditions such as coronary heart disease and obesity, as well as the promotion of physical function and mental well-being. The significance of exercise as a health-related behaviour has brought to the fore the need to address motivational problems associated with its adoption and maintenance. In this respect, exercise psychology research would appear to provide potential for guiding significant public health initiatives. This paper addresses the issues of exercise and mental health and exercise motivation with a view to highlighting key sections of the exercise psychology literature for health and medical psychologists.