Showing papers by "Brigham Young University published in 1997"

Improved heterogeneous distance functions

Abstract: Instance-based learning techniques typically handle continuous and linear input values well, but often do not handle nominal input attributes appropriately. The Value Difference Metric (VDM) was designed to find reasonable distance values between nominal attribute values, but it largely ignores continuous attributes, requiring discretization to map continuous values into nominal values. This paper proposes three new heterogeneous distance functions, called the Heterogeneous Value Difference Metric (HVDM), the Interpolated Value Difference Metric (IVDM), and the Windowed Value Difference Metric (WVDM). These new distance functions are designed to handle applications with nominal attributes, continuous attributes, or both. In experiments on 48 applications the new distance metrics achieve higher classification accuracy on average than three previous distance functions on those datasets that have both nominal and continuous attributes.

Reverse engineering of geometric models—an introduction

Abstract: In many areas of industry, it is desirable to create geometric models of existing objects for which no such model is available. This paper reviews the process of reverse engineering of shapes. After identifying the purpose of reverse engineering and the main application areas, the most important algorithmic steps are outlined and various reconstruction strategies are presented. Pros and cons of various data acquisition techniques are described with related problems of boundary representation model construction. Specific issues addressed include characterization of geometric models and related surface representations, segmentation and surface fitting for simple and free-form shapes, multiple view combination and creating consistent and accurate B-rep models. The limitations of currently known solutions are also described, and we point out areas in which further work is required before reverse engineering of shape becomes a practical, widely-available engineering tool.

AICA riboside increases AMP-activated protein kinase, fatty acid oxidation, and glucose uptake in rat muscle

Abstract: 5-Aminoimidazole-4-carboxamide ribonucleoside (AICAR) has previously been reported to be taken up into cells and phosphorylated to form ZMP, an analog of 5′-AMP This study was designed to determin

The Strepsiptera problem: phylogeny of the holometabolous insect orders inferred from 18S and 28S ribosomal DNA sequences and morphology.

Abstract: Phylogenetic relationships among the holometabolous insect orders were inferred from cladistic analysis of nucleotide sequences of 18S ribosomal DNA (rDNA) (85 exemplars) and 28S rDNA (52 exemplars) and morphological characters. Exemplar outgroup taxa were Collembola (1 sequence), Archaeognatha (1), Ephemerida (1), Odonata (2), Plecoptera (2), Blattodea (1), Mantodea (1), Dermaptera (1), Orthoptera (1), Phasmatodea (1), Embioptera (1), Psocoptera (1), Phthiraptera (1), Hemiptera (4), and Thysanoptera (1). Exemplar ingroup taxa were Coleoptera: Archostemata (1), Adephaga (2), and Polyphaga (7); Megaloptera (1); Raphidioptera (1); Neuroptera (sensu stricto = Planipennia): Mantispoidea (2), Hemerobioidea (2), and Myrmeleontoidea (2); Hymenoptera: Symphyta (4) and Apocrita (19); Trichoptera: Hydropsychoidea (1) and Limnephiloidea (2); Lepidoptera: Ditrysia (3); Siphonaptera: Pulicoidea (1) and Ceratophylloidea (2); Mecoptera: Meropeidae (1), Boreidae (1), Panorpidae (1), and Bittacidae (2); Diptera: Nematocera (1), Brachycera (2), and Cyclorrhapha (1); and Strepsiptera: Corioxenidae (1), Myrmecolacidae (1), Elenchidae (1), and Stylopidae (3). We analyzed approximately 1 kilobase of 18S rDNA, starting 398 nucleotides downstream of the 5' end, and approximately 400 bp of 28S rDNA in expansion segment D3. Multiple alignment of the 18S and 28S sequences resulted in 1,116 nucleotide positions with 24 insert regions and 398 positions with 14 insert regions, respectively. All Strepsiptera and Neuroptera have large insert regions in 18S and 28S. The secondary structure of 18S insert 23 is composed of long stems that are GC rich in the basal Strepsiptera and AT rich in the more derived Strepsiptera. A matrix of 176 morphological characters was analyzed for holometabolous orders. Incongruence length difference tests indicate that the 28S + morphological data sets are incongruent but that 28S + 18S, 18S + morphology, and 28S + 18S + morphology fail to reject the hypothesis of congruence. Phylogenetic trees were generated by parsimony analysis, and clade robustness was evaluated by branch length, Bremer support, percentage of extra steps required to force paraphyly, and sensitivity analysis using the following parameters: gap weights, morphological character weights, methods of data set combination, removal of key taxa, and alignment region. The following are monophyletic under most or all combinations of parameter values: Holometabola, Polyphaga, Megaloptera + Raphidioptera, Neuroptera, Hymenoptera, Trichoptera, Lepidoptera, Amphiesmenoptera (Trichoptera + Lepidoptera), Siphonaptera, Siphonaptera + Mecoptera, Strepsiptera, Diptera, and Strepsiptera + Diptera (Halteria). Antliophora (Mecoptera + Diptera + Siphonaptera + Strepsiptera), Mecopterida (Antliophora + Amphiesmenoptera), and Hymenoptera + Mecopterida are supported in the majority of total evidence analyses. Mecoptera may be paraphyletic because Boreus is often placed as sister group to the fleas; hence, Siphonaptera may be subordinate within Mecoptera. The 18S sequences for Priacma (Coleoptera: Archostemata), Colpocaccus (Coleoptera: Adephaga), Agulla (Raphidioptera), and Corydalus (Megaloptera) are nearly identical, and Neuropterida are monophyletic only when those two beetle sequences are removed from the analysis. Coleoptera are therefore paraphyletic under almost all combinations of parameter values. Halteria and Amphiesmenoptera have high Bremer support values and long branch lengths. The data do not support placement of Strepsiptera outside of Holometabola nor as sister group to Coleoptera. We reject the notion that the monophyly of Halteria is due to long branch attraction because Strepsiptera and Diptera do not have the longest branches and there is phylogenetic congruence between molecules, across the entire parameter space, and between morphological and molecular data.

A Review of Literature on Teaching Engineering Design Through Project‐Oriented Capstone Courses

Abstract: Teaching engineering design through senior project or capstone engineering courses has increased in recent years. The trend toward increasing the design component in engineering curricula is part of an effort to better prepare graduates for engineering practice. This paper describes the standard practices and current state of capstone design education throughout the country as revealed through a literature search of over 100 papers relating to engineering design courses. Major topics include the development of capstone design courses, course descriptions, project information, details of industrial involvement, and special aspects of team-oriented design projects. An extensive list of references is provided.

Traveling Waves in a Convolution Model for Phase Transitions

Abstract: The existence, uniqueness, stability and regularity properties of traveling-wave solutions of a bistable nonlinear integrodifferential equation are established, as well as their global asymptotic stability in the case of zero-velocity continuous waves. This equation is a direct analog of the more familiar bistable nonlinear diffusion equation, and shares many of its properties. It governs gradient flows for free-energy functionals with general nonlocal interaction integrals penalizing spatial nonuniformity.

Fraudulently Misstated Financial Statements and Insider Trading: An Empirical Analysis

Abstract: This study investigates the relationship between insider trading and fraud. We find that in the presence of fraud, insiders reduce their holdings of company stock through high levels of selling activity as measured by either the number of transactions, the number of shares sold, or the dollar amount of shares sold. Moreover, we present evidence that a cascaded logit model, incorporating insider trading variables and firm-specific financial characteristics, differentiates companies with fraud from companies without fraud.

Pitfalls in Tests for Changes in Correlations

Abstract: Correlations are crucial for pricing and hedging derivatives whose payoff depends on more than one asset. Typically, correlations computed separately for ordinary and stressful market conditions differ considerably, a pattern widely termed "correlation breakdown." As a result, risk managers worry that their hedges will be useless when they are most needed, namely during "stressful" market situations. We show that such worries may not be justified since "correlation breakdowns" can easily be generated by data whose distribution is stationary and, in particular, whose correlation coefficient is constant. We make this point analytically, by way of several numerical examples, and via an empirical illustration. But, risk managers should not necessarily relax. Although "correlation breakdown" can be an artifact of poor data analysis, other evidence suggests that correlations do in fact change over time, though not in a way that is correlated with "stressful" market conditions.

Religious influence on marital stability.

Abstract: Researchers frequently postulate a strong relationship between religiosity and marital stability. We incorporate a multidimensional specification of religiosity into event-history models of the religion-marital stability relationship. Results are based on panel data from the National Survey of Families and Households (N = 4,587 married couples). While no single dimension of religiosity adequately describes the effect of religious experience on marital stability, the frequency of religious attendance has the greatest positive impact on marital stability. When both spouses attend church regularly, the couple has the lowest risk of divorce. Spouse differences in church attendance increase the risk of dissolution. All significant religious affiliation influences disappear once demographic characteristics are controlled. The wife's religious beliefs concerning marital commitment and nonmarital sex are more important to the stability of the marriage than the husband's beliefs.

Communication Strategies in a Second Language: Definitions and Taxonomies

Abstract: This paper examines trends in second language (L2) communication strategy (CS) research to date. We give a comprehensive review of the relevant literature from the last two decades, with particular consideration of the different ways in which CSs have been defined and of corresponding influences on the organization of strategy taxonomies. We first outline the history of CS research and discuss problem-orientedness and consciousness as defining criteria for CSs. We then offer a comprehensive list of strategic language devices and describe the major CS taxonomies, noting key trends, with special attention to current and future research orientations.

Socialization in Context Connection, Regulation, and Autonomy in the Family, School, and Neighborhood, and with Peers

Abstract: This study investigated the relation to school grades, feelings of depression, and antisocial behavior of youth perceptions of three central dimensions of socialization (connection with significantothers, regulation of behavior, andpsychological autonomy) as they are experienced infour social contexts: family, school, neighborhood, ndpeers. Analyses of a random sample of 900 fifth and eighth-grade youth included both descriptive accounts of youth experience in these contexts and testedfor various models predicting independent and interactive effects among contexts on youth functioning. Findings showed that connection, regulation, and autonomy were meaningful dimensions of socialization experience in the four contexts, thatfamily and peers were primary socialization domains, and that discrete aspects of youth functioning were related to specific contexts. There was some evidence that deficits in experience in one context can be compensatedfor by experience in other contexts.

Antecedents and Consequences of Burnout in Accounting: Beyond the Role Stress Model

Abstract: The burnout condition of employees is a well-known phenomenon in psychology and several applied business disciplines. Despite some degree of recognition in the practice community, little explicit academic accounting recognition of this topic appears to exist. This paper introduces the burnout construct by showing that it has not been captured by other concepts in the literature. In addition to hypothesizing that burnout is directly related to several behavioral and attitudinal outcomes in public accounting practice, this paper proposes that burnout mediates the impact of role stressors on those outcomes. Within a national sample of accountants, the burnout condition is found to negatively affect satisfaction and performance and to positively affect turnover intentions. Furthermore, burnout partially mediated the influence of role conflict, role ambiguity and role overload on those outcomes. To some extent, burnout is capable of separating the functional and dysfunctional aspects of the role stressors on job outcomes.

Mapping groundwater contamination using dc resistivity and VLF geophysical methods; a case study

Abstract: Geophysical methods can be helpful in mapping areas of contaminated soil and groundwater. Electrical resistivity and very low-frequency electromagnetic induction (VLF) surveys were carried out at a site of shallow hydrocarbon contamination in Utah County, Utah. Previously installed monitoring wells facilitated analysis of water chemistry to enhance interpretation of the geophysical data. The electrical resistivity and VLF data correlate well, and vertical cross-sections and contour maps generated from these data helped map the contaminant plume, which was delineated as an area of high interpreted resistivities.

Activation of the furin endoprotease is a multiple‐step process: requirements for acidification and internal propeptide cleavage

Abstract: Activation of furin requires autoproteolytic cleavage of its 83‐amino acid propeptide at the consensus furin site, Arg‐Thr‐Lys‐Arg107 ↓ . This RER‐localized cleavage is necessary, but not sufficient, for enzyme activation. Rather, full activation of furin requires exposure to, and correct routing within, the TGN/endosomal system. Here, we identify the steps in addition to the initial propeptide cleavage necessary for activation of furin. Exposure of membrane preparations containing an inactive RER‐localized soluble furin construct to either: (i) an acidic and calcium‐containing environment characteristic of the TGN; or (ii) mild trypsinization at neutral pH, resulted in the activation of the endoprotease. Taken together, these results suggest that the pH drop facilitates the removal of a furin inhibitor. Consistent with these findings, following cleavage in the RER, the furin propeptide remains associated with the enzyme and functions as a potent inhibitor of the endoprotease. Co‐immunoprecipitation studies coupled with analysis by mass spectrometry show that release of the propeptide at acidic pH, and hence activation of furin, requires a second cleavage within the autoinhibitory domain at a site containing a P6 arginine (‐Arg70‐Gly‐Val‐Thr‐Lys‐Arg75 ↓ ‐). The significance of this cleavage in regulating the compartment‐specific activation of furin, and the relationship of the furin activation pathway to those of other serine endoproteases are discussed.

Phosphorylation of rat muscle acetyl-CoA carboxylase by AMP-activated protein kinase and protein kinase A.

Abstract: Winder, W. W., H. A. Wilson, D. G. Hardie, B. B. Rasmussen, C. A. Hutber, G. B. Call, R. D. Clayton, L. M. Conley, S. Yoon, and B. Zhou. Phosphorylation of rat muscle acetyl-CoA carboxylase by AMP-...

Electrical stimulation inactivates muscle acetyl-CoA carboxylase and increases AMP-activated protein kinase

Abstract: Muscle malonyl-CoA decreases during exercise or electrical stimulation, the exercise-induced decline being accompanied by changes in the kinetic properties [maximal velocity (Vmax), activation cons

Participative Decision-Making: An Integration of Multiple Dimensions:

Abstract: Few topics have resulted in as much theory, empirical study, controversy, and practical application as participative decision-making (PDM). Although most past empirical research has assumed that the decision-making process in PDM was unidimensional, this paper explores a multidimensional view and examines the integration of degree of participation and decision-making processes and their relationship with satisfaction and performance. The results suggest that the degree of involvement in generating alternatives, planning, and evaluating results are related significantly to satisfaction and that degree of involvement in generating alternatives and planning are related significantly to performance.

Instance Pruning Techniques

Abstract: The nearest neighbor algorithm and its derivatives are often quite successful at learning a concept from a training set and providing good generalization on subsequent input vectors. However, these techniques often retain the entire training set in memory, resulting in large memory requirements and slow execution speed, as well as a sensitivity to noise. This paper provides a discussion of issues related to reducing the number of instances retained in memory while maintaining (and sometimes improving) generalization accuracy, and mentions algorithms other researchers have used to address this problem. It presents three intuitive noise-tolerant algorithms that can be used to prune instances from the training set. In experiments on 29 applications, the algorithm that achieves the highest reduction in storage also results in the highest generalization accuracy of the three methods.

Semi-structured interviewing for user-centered design

Abstract: An obvious, but critical, ingredient of user-centered design of software applications is for designers to gain a thorough understanding of potential users’ work (including its surrounding context) which an intended application will support. This involves observing potential users and interviewing them about their work. The goal is to produce a descriptive model of current work practice that can be used to guide further design activities (e.g., how the worker will become more productive through introduction of a new or improved computer support application). In order to make that process more efficient, I have developed the semi-structured interviewing techniques described here. The techniques are adaptations of methods used by ethnographers [15, 16] and those used by cognitive scientists [4], and are based on previous work that my colleagues and I have done on knowledge elicitation for knowledge-based (expert) systems [5, 18]. A for Semi-Structured Interviewing

Seeking solutions in configurable computing

Abstract: Configurable computing offers the potential of producing powerful new computing systems. Will current research overcome the dearth of commercial applicability to make such systems a reality? Unfortunately, no system to date has yet proven attractive or competitive enough to establish a commercial presence. We believe that ample opportunity exists for work in a broad range of areas. In particular, the configurable computing community should focus on refining the emerging architectures, producing more effective software/hardware APIs, better tools for application development that incorporate the models of hardware reconfiguration, and effective benchmarking strategies.

Concurrent and construct validity of the outcome questionnaire.

Abstract: The Outcome Questionnaire (OQ) was developed by Lambert and colleagues (1994) as a standardized measure for assessing psychotherapy outcome. Although the instrument is already being widely used in managed health care quality control, further evidence of its psychometric properties is needed. This research evaluated the concurrent and construct validity of the OQ with three patient samples and a sample of community participants. Support was found for the construct and concurrent validity of the OQ with both patients (n = 183) and nonpatients (n = 210). The data show significant differences in scores between patients and community samples, as well as differences between the various clinical samples with varying levels of pathology. Although high correlations between the OQ Total (and subscale) scores and the criterion measures were found, high intercorrelations among subscales suggest considerable shared variance between subscales. The OQ Total score appears promising as a measure of general psychological d...

Body Fat Percentage of Children Varies According to Their Diet Composition

Abstract: Objective To ascertain the association between diet composition and body fat percentage in 9- and 10-year-old children. Also, to examine the influence of gender, total energy intake, fitness, physical activity, and parental body mass on the relationship between diet composition and adiposity. Design Diet composition was assessed using the National Cancer Institute food frequency questionnaire, and adiposity was measured using the average of results determined using two skinfold equations. Fitness levels and physical activity were ascertained using the 1-mile run/walk test and a self-report 15-item scale, respectively. Subjects A sample of 262 children (162 boys and 100 girls, mean age=9.8±0.5 years) participated. Statistical analysis Regression analysis was used to determine the extent to which diet composition contributed to adiposity without statistical control for any potentially confounding variables. Partial correlations were calculated to assess the relationship between macronutrient intake and adiposity after potential confounders (gender, total energy intake, physical fitness, and parental body mass) were controlled statistically. Results Energy intake was positively related to adiposity. Fat intake, calculated as a percentage of total energy, was also positively related to adiposity, before and after control for potential confounding variables. Percentage of energy derived from carbohydrate was inversely related to adiposity, before and after controlling for potential confounders. Applications These findings indicate that the macronutrient intake of children, particularly dietary fat and carbohydrate intake, may play a role in adiposity, independent of the influence of total energy intake, gender, physical fitness, and parental body mass index.

Testing Species Boundaries in Biodiversity Studies

Abstract: A paper recently published by Phillips et al. (1996) reported a molecular genetic study of all recognized subspecies of the common snapping turtle ( Chelydra serpentina) and concluded from patterns of geographic variation in isozyme and mitochondrial DNA restriction fragment pattern data that three evolutionary species should be recognized in this group. We suggest that this paper is fundamentally flawed because it fails to present any species concept as a testable hypothesis. Data are collected in the absence of any conceptual framework for diagnosing species boundaries, so no criteria for acceptance or rejection of a preferred hypothesis are formulated, and species boundaries are determined in a nonrigorous, post hoc manner. Further, the absence of specific criteria for species diagnosis in this case leads to flaws in sampling design, data collection, and data analysis. Because these design flaws are typical of many studies, we briefly outline three different lineage-based operational species concepts (phylogenetic, concordance, and cohesion) and present an alternative interpretation of the Chelydra data, insofar as this is possible given the design limitations. We conclude the following: (1) species status may not be warranted for the Central and South American taxa, (2) more-detailed analysis is warranted in the U.S. population because distinct lineage may be obscured by poor lab technique or introgression of mtDNA, and (3) the Ecuadorean population may deserve species status based on fixed nuclear isozyme loci. We recommend the following procedures for implementation of lineage-based species concepts within a rigorous hypothesis testing framework. First, if an animal is to be sacrificed, proper care should be taken to utilize different tissues for multiple pass electrophoresis. This will unmask hidden heterogeneity and maximize the number of resolved loci. Second, when phylogenetic relationships are reconstructed with restriction fragment length polymorphism data, fragment data should be converted to site data to avoid uncertainties in homology. Finally, a proper sampling scheme should be designed to address the question of species status in terms of numbers of individuals, genetic loci, populations, and geographic regions. Comprobar Demarcaciones de Especies en Investigaciones de Biodiversidad Un articulo publicado recientemente por Phillips et al. (1996), reporto un estudio acerca de la genetica molecular en todos las subespecies reconocidos de la tortuga comun ( Chelydra serpentina). Se concluyo, con base en los patrones de variacion geografica en isoenzimas y en fragmentos de restriccion de ADN mitocondrial, que tres especies evolutivas deberian ser reconocidas en este grupo. Nosotros sugerimos que ese articulo esta mal fundamentado porque no presenta un concepto de especie como hipotesis a probar. Por consiguiente, los datos son obtenidos en ausencia de un marco conceptual para diagnosticar limites de especies. Esto es, que no se formula un criterio para la aceptacion o rechazo de una hipotesis adoptada y los limites de especie son determinados de una manera post hoc y no rigurosa. Ademas, la ausencia de criterios especificos para la diagnosis de especies, en este caso, lleva a un inadecuado diseno de muestreo, obtencion de datos y analisis de los mismos. Debido a que estos disenos inadecuados son tipicos en muchos estudios, nosotros damos brevemente los lineamientos de tres diferentes conceptos operacionales de especie basados en linajes ( filogenetico, de concordancia y de cohesion) y presentamos una interpretacion alternativa para los datos de Cheyldra, hasta donde es posible, dadas las limitaciones del diseno. Concluimos lo siguiente: (1) el estatus de especie puede no ser garantizado para los taxa de Centro y Suramerica, (2) un analisis mas detallado es requerido en las poblaciones de U.S. ya que tecnicas deficientes de laboratorio o la introgresion de mtADN pueden dificultar la distincion de linajes, y (3) las poblaciones ecuatorianas podrian recibir el estatus de especie con base en loci fijados de isoemzimas nucleares. Recomendamos lo siguiente para la implementacion de conceptos de especie basados en linajes dentro de un riguroso marco de hipotesis a probar. Primero, si un animal va a ser sacrificado, se debe asegurar el uso de diferentes tejidos para multiples corridas de electroforesis. Esto descubrira heterogeneidad escondida y maximizara el numero de loci resueltos. Segundo, al construir las relaciones filogeneticas con datos de polimorfismos en longitud de fragmentos de restriccion, se deberia de convertir los datos de fragmentos en datos de sitios para evitar dudas en la homologia. Finalmente, se deberia disenar un apropiado esquema de muestreo para abordar la pregunta del estatus de especie en terminos de numero de individuos, loci geneticos, poblaciones y regiones geograficas.

An Expected-Indemnity Approach to the Measurement of Moral Hazard in Crop Insurance

Abstract: A definition of moral hazard in multiple peril crop insurance is proposed that focuses on expected indemnities rather than input use. Five years of production and insurance data for a panel of Kansas wheat farms is used to empirically test for this type of moral hazard. Results suggest that moral hazard affects multiple peril crop insurance indemnities in poor production years but that no significant moral hazard occurs in years when growing conditions are favorable.