Showing papers by "Brigham Young University published in 1999"
TL;DR: Increased recruitment of the AMPK signaling system, either by exercise or pharmaceutical activators, may be effective in correcting insulin resistance in patients with forms of impaired glucose tolerance and Type 2 diabetes resulting from defects in the insulin signaling cascade.
Abstract: Adenosine 5′-monophosphate-activated protein kinase (AMPK) now appears to be a metabolic master switch, phosphorylating key target proteins that control flux through metabolic pathways of hepatic k...
990 citations
TL;DR: The concept of maternal gatekeeping is defined as a collection of beliefs and behaviors that ultimately inhibit a collaborative effort between men and women in family work by limiting men's opportunities for learning and growing through caring for home and children as discussed by the authors.
Abstract: Maternal gatekeeping is conceptualized within the framework of the social construction of gender and is defined as having three dimensions: mothers' reluctance to relinquish responsibility over family matters by setting rigid standards, external validation of a mothering identity, and differentiated conceptions of family roles. These three conceptual dimensions of gatekeeping are operationalized with modest reliability and tested with a confirmatory factor analysis on a sample of 622 dual-earner mothers. With cluster analyses, 21% of the mothers were classified as gatekeepers. Gatekeepers did 5 more hours of family work per week and had less equal divisions of labor than women classified as collaborators. Key Words: domestic labor, fathers, mothers. Although men's and women's time in family work is converging (Levine & Pittinsky, 1997; Robinson & Godbey, 1997), women are still doing more family work than men (Demo & Acock, 1993). The prevailing explanations for this unequal distribution of family work are grounded in theories of family power and focus on four major conceptual approaches: relative resources, time availability, economic dependency, and gender ideology (Greenstein, 1996). Although research literature provides partial validity to each of these approaches, Thompson and Walker (1989) argue that these explanations do not explain why wives continue to do a larger share of family work, despite paid employment outside the home. Perhaps a more effective approach to understanding the division of family labor is one that examines family processes by asking what conditions are necessary for wives and husbands to care collaboratively for their home and children (Thompson, 1992, 1993; Thompson & Walker, 1995). Although scholars have documented that many fathers want to increase the amount of time spent caring for their home and children (Daly, 1993; Lamb, 1997; Pleck, 1997), there are many structural, cultural, familial, and personal barriers to increased father involvement in family work. Daily child care and household tasks can provide an opportunity for both husbands and wives to be connected and committed to protecting, promoting, and nurturing the growth of their children (Hawkins, Christiansen, Sargent, & Hill, 1993). However, more needs to be known about the specific contextual factors that may mediate or regulate men's involvement in family work. Specifically, how women's beliefs and behaviors toward men's involvement affect actual levels of involvement needs more attention (De Luccie, 1995). Scholars have noted that wives as well as husbands resist more collaborative arrangements of family work (Coltrane, 1996; Dienhart & Daly, 1997; Thompson & Walker, 1989). One way women resist increased men's involvement in family work is by "gatekeeping" the domain of home and family. The term "maternal gatekeeping," however, is somewhat problematic and needs clarification. Briefly, maternal gatekeeping is a collection of beliefs and behaviors that ultimately inhibit a collaborative effort between men and women in family work by limiting men's opportunities for learning and growing through caring for home and children. It is clear from its frequent appearance in the scholarly literature (Coltrane, 1989, 1996; De Luccie, 1995; Dienhart & Daly, 1997; Ferree, 1991; Greenstein, 1996; Haas, 1980, 1992; Hawkins & Dollahite, 1997; Hawkins & Roberts, 1992; Hochschild, 1989; Hoffman, 1983; Komter, 1989; Palkovitz, 1984; Pleck, 1983, 1985; Schipani, 1994; Thompson & Walker, 1989; Whiteside, 1998) that maternal gatekeeping can be one important source of men's underinvolvement in domestic labor and may inhibit mutually satisfactory arrangements for sharing family work. As yet, however, no one has carefully conceptualized or operationalized the concept. Consideration of the nature of gatekeeping may prove to be useful in understanding both the ambivalence that many men and women feel toward men's increased involvement and some of the conditions necessary for men and women to work collaboratively in daily family work. …
798 citations
TL;DR: Evidence is provided that the increased glucose uptake observed with AMPK activation by AICA-riboside in perfused rat hindlimb muscles is due to an increase in the translocation of GLUT4 to surface membranes.
Abstract: It has previously been reported that exercise causes an increase in glucose uptake in skeletal muscle and also an increase in 5' AMP-activated protein kinase (AMPK) activity. 5-Aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside (AICA-riboside), an analog of adenosine, is taken up into cells and phosphorylated to form AICA-riboside monophosphate (ZMP), which can also activate AMPK. This study was designed to determine whether the increase in glucose uptake observed with AMPK activation by AICA-riboside is due to GLUT4 translocation from an intracellular location to the plasma membranes, similar to that seen in response to contraction. Rat hindlimbs were perfused with Krebs-Henseleit bicarbonate containing 4% bovine serum albumin, washed bovine erythrocytes, 8 mmol/l glucose, and +/-2 mmol/AICA-riboside or +/-60 nmol/l insulin. Perfusion medium containing AICA-riboside was found to significantly increase AMPK activity, glucose uptake, and GLUT4 translocation in skeletal muscle above basal levels. Insulin-perfused muscles showed significant increases in glucose uptake and GLUT4 translocation, but AMPK activation was not significantly changed from basal levels. These results provide evidence that the increased glucose uptake observed with AMPK activation by AICA-riboside in perfused rat hindlimb muscles is due to an increase in the translocation of GLUT4 to surface membranes.
700 citations
TL;DR: It is suggested that changes in cardiac autonomic function reflected by changes in mean HR and HRV may be part of the pathophysiologic mechanisms or pathways linking cardiovascular mortality and particulate air pollution.
597 citations
TL;DR: In this article, the authors show that the estimated separate contributions of sets of dummy variables to the explained portion and the overall decomposition are not dependent upon the choice of left-out reference groups.
Abstract: The standard wage decomposition methodology produces arbitrary results when attempting to estimate the separate contributions of sets of dummy variables to the unexplained portion of the wage decomposition: the estimates are not invariant with respect to the choice of reference groups. However, the estimated separate contributions of sets of dummy variables to the explained portion and the overall decomposition are shown not to be dependent upon the choice of left-out reference groups. A similar identification problem applies to continuous variables, although this may not be as likely to cause problems in practice.
589 citations
TL;DR: Although overall synchronization rate with Ovsynch was above 85%, there were clear differences in response according to day of protocol initiation, with cows in which Ov synch was initiated at midcycle having smaller ovulatory follicles and greater pregnancy rates.
579 citations
TL;DR: Chronic chemical activation of AMPK results in increases in GLUT-4 protein, hexokinase activity, and glycogen, similarly to those induced by endurance training.
Abstract: This study was designed to determine whether chronic chemical activation of AMP-activated protein kinase (AMPK) would increase glucose transporter GLUT-4 and hexokinase in muscles similarly to peri...
514 citations
TL;DR: In this article, the authors explicitly model high school students' choice of college type (characterized by selectivity and control) based on individual and family characteristics (including ability and parental economic status) and an estimate of the net costs of attendance.
Abstract: Although a substantial and rising labor market premium is associated with college attendance in general, little is known about how this premium varies across institutions of different types and across time. In this paper we explicitly model high school students' choice of college type (characterized by selectivity and control) based on individual and family characteristics (including ability and parental economic status) and an estimate of the net costs of attendance. We estimate selectivity-corrected outcome equations using data from both the National Longitudinal Study of the High School Class of 1972 and High School and Beyond, which permit us to determine the effects of college quality on wages and earnings and how this effect varies across time. Even after controlling for selection effects, strong evidence emerges of a significant economic return to attending an elite private institution, and some evidence suggests this premium has increased over time.
490 citations
01 Nov 1999
TL;DR: Experiments show that it is possible to achieve good recall and precision ratios for documents that are rich in recognizable constants and narrow in ontological breadth in a conceptual-modeling approach.
Abstract: Electronically available data on the Web is exploding at an ever increasing pace. Much of this data is unstructured, which makes searching hard and traditional database querying impossible. Many Web documents, however, contain an abundance of recognizable constants that together describe the essence of a document's content. For these kinds of data-rich, multiple-record documents (e.g., advertisements, movie reviews, weather reports, travel information, sports summaries, financial statements, obituaries, and many others) we can apply a conceptual-modeling approach to extract and structure data automatically. The approach is based on an ontology – a conceptual model instance – that describes the data of interest, including relationships, lexical appearance, and context keywords. By parsing the ontology, we can automatically produce a database scheme and recognizers for constants and keywords, and then invoke routines to recognize and extract data from unstructured documents and structure it according to the generated database scheme. Experiments show that it is possible to achieve good recall and precision ratios for documents that are rich in recognizable constants and narrow in ontological breadth. Our approach is less labor-intensive than other approaches that manually or semiautomatically generate wrappers, and it is generally insensitive to changes in Web-page format.
377 citations
TL;DR: The pattern of cardiopulmonary health effects associated with particulate air pollution, which has been observed by epidemiological studies, is the strongest evidence of the health effects of this pollution.
Abstract: Publisher Summary This chapter discusses the adverse effects of particulate air pollution on health The overall epidemiologic evidence is consistent with the premise that particulate air pollution common to many urban and industrial environments is an important risk factor for cardiopulmonary disease and mortality Although the biological linkages remain poorly understood, the results of the acute and chronic exposure studies are complementary Much of the recent epidemiological effort has focused on the effects of acute exposure, primarily because of the relative availability of relevant time-series data sets However, the effects of chronic exposure may be more important in terms of overall public health relevance Long-term, repeated exposure increases the risk of chronic respiratory disease and the risk of cardiorespiratory mortality Short-term exposures can exacerbate existing cardiovascular and pulmonary disease and increase the number of persons in a population who become symptomatic, require medical attention, or die The pattern of cardiopulmonary health effects associated with particulate air pollution, which has been observed by epidemiological studies, is the strongest evidence of the health effects of this pollution
373 citations
TL;DR: An improved scoring tool for research and development (R&D) project evaluation and selection is presented that ranks project alternatives based on the criteria of relevance, risk, reasonableness, and return.
Abstract: An improved scoring tool for research and development (R&D) project evaluation and selection is presented that ranks project alternatives based on the criteria of relevance, risk, reasonableness, and return. The scoring algorithm explicitly incorporates tradeoffs among the evaluation criteria and calculates a relative measure of project value by taking into account the fact that value is a function of both merit and cost. Implementation of the selection method in a federal research laboratory is discussed. A comprehensive overview of the R&D project selection literature is included.
TL;DR: The results suggest that fluctuating population sizes during the late Pleistocene have left a genetic signature on levels of variation in both species, and a statistical parsimony analysis indicates local genetic structure that suggests recent restricted gene flow.
Abstract: The grey wolf (Canis lupus) and coyote (C. latrans) are highly mobile carnivores that disperse over great distances in search of territories and mates. Previous genetic studies have shown little geographical structure in either species. However, populatio
TL;DR: Evidence is provided for a medical cost-offset effect, specifically in the domain of behavioral medicine, in the context of psychological treatments and patients being treated only for psychological disorders including substance abuse.
Abstract: The impact of psychological interventions on the use of medical services was evaluated by examining the outcome of 91 studies published between 1967 and 1997 using meta-analytic techniques and percentage estimates. Psychological treatments included various forms of psychotherapy, behavioral medicine, and psychiatric consultation. Patients included those undergoing medical procedures such as surgery, patients with a history of ovemtilization, and patients being treated only for psychological disorders including substance abuse. Results provided evidence for a medical cost-offset effect, specifically in the domain of behavioral medicine. Average savings resulting from implementing psychological interventions was estimated to be about 20%. About one third of the articles demonstrated that dollar savings continued to be substantial even when the cost of providing the psychological intervention was subtracted from the savings. The role of moderating variables such as patient age and type of problem was analyzed and discussed.
TL;DR: Medication treatments are often not used in treating ADHD children identified in the community, suggesting the need for better education of parents, physicians, and mental health professionals about the effectiveness of these treatments.
Abstract: Objective To address rising concerns about the possible overdiagnosis of attention-deficit hyperactivity disorder (ADHD) and overtreatment with stimulants. To date, almost no studies have examined ADHD in unbiased community-based studies, ascertaining both the prevalence of the diagnosis within nonreferred populations and the extent to which various treatments (i.e., stimulant medication, mental health treatments, and educational interventions) are used. Method As a part of the Methods for the Epidemiology of Child and Adolescent Mental Disorders (MECA) Study, the authors examined epidemiological survey data obtained from 1,285 children and their parents across 4 U.S. communities. Analyses examined the frequency of children's ADHD diagnosis, the extent to which medications were prescribed, as well as the provision of other services (e.g., psychosocial treatments, school-based educational interventions). Results Findings indicated that 5.1% of children met full DSM-III-R ADHD criteria across the pooled sample. Only 12.5% of children meeting ADHD criteria had been treated with stimulants during the previous 12 months. Some children who had been prescribed stimulants did not meet full ADHD diagnostic criteria, but these children manifested high levels of ADHD symptoms, suggesting that the medication had been appropriately prescribed. Children with ADHD were generally more likely to receive mental health counseling and/or school-based interventions than medication. Conclusions Medication treatments are often not used in treating ADHD children identified in the community, suggesting the need for better education of parents, physicians, and mental health professionals about the effectiveness of these treatments. On the basis of these data it cannot be concluded that substantial “overtreatment” with stimulants is occurring across communities in general.
01 Jun 1999
TL;DR: This paper describes a heuristic approach to discovering record boundaries in Web documents that captures the structure of a document as a tree of nested HTML tags, and locates the subtree containing the records of interest using five independent heuristics and selects a consensus separator tag based on a combined heuristic.
Abstract: Extraction of information from unstructured or semistructured Web documents often requires a recognition and delimitation of records. (By “record” we mean a group of information relevant to some entity.) Without first chunking documents that contain multiple records according to record boundaries, extraction of record information will not likely succeed. In this paper we describe a heuristic approach to discovering record boundaries in Web documents. In our approach, we capture the structure of a document as a tree of nested HTML tags, locate the subtree containing the records of interest, identify candidate separator tags within the subtree using five independent heuristics, and select a consensus separator tag based on a combined heuristic. Our approach is fast (runs linearly for practical cases within the context of the larger data-extraction problem) and accurate (100% in the experiments we conducted).
TL;DR: In this paper, a review of the state-of-the-art of the various components or submodels that are required in a comprehensive combustion model is presented, and representative applications of comprehensive combustion models are summarized, and three sets of model simulations are compared with experimental data.
TL;DR: Changes in pulse rate could reflect cardiac rhythm changes and may be part of the pathophysiology linking particles to cardiopulmonary mortality, and the observed lag structure is consistent with particulate-induced pulmonary inflammation and cytokine release.
Abstract: Although epidemiological studies have linked particulate air pollution with cardiopulmonary mortality, underlying biological mechanisms remain largely unknown. Unexplored pathophysiological pathways include transient declines in blood oxygenation and/or changes in cardiac rhythm following particulate exposure. In this study, blood oxygen saturation using pulse oximetry (SpO2) and pulse rate were measured daily on a panel of 90 elderly subjects during the winter of 1995-1996 in Utah Valley. Associations of SpO2 and pulse rate with respirable particulate pollution (particles with an aerodynamic diameter
TL;DR: It is theorised that importance is not adequately represented as a point estimate, but is a function of performance, which can change the relative priority of subsequent improvement efforts.
Abstract: Services and products possess various attributes, some being more important than others. Importance-Performance Analysis (IPA) is a technique for prioritising attributes based on measurements of performance and importance. A weakness of IPA is that it conceptualises attribute importance as a scalar which is independent of attribute performance. In this article we theorise that importance is not adequately represented as a point estimate, but is a function of performance. When attribute performance changes, importance does also, which can change the relative priority of subsequent improvement efforts. Empirical results are presented which support our theory, The nature of the performance-importance response function is discussed, along with implications. Ideas for future research are also discussed, including application of the findings to quality modelling (SERVQUAL) and other decision support methodologies (Quality Function Deployment and the Analytic Hierarchy Process).
TL;DR: A unique lipopeptide antimycotic, termed cryptocandin, is described from Cryptosporiopsis cf.
Abstract: A unique lipopeptide antimycotic, termed cryptocandin, is described from Cryptosporiopsis cf. quercina, an endophytic fungus. Cryptocandin, with a molecular mass of 1079 Da, contains equimolar amounts of 3,4-dihydroxyhomotyrosine, 4-hydroxyproline, threonine, glutamine, 3-hydroxy-4-hydroxymethylproline, 4,5-dihydroxyornithine and palmitic acid. Cryptocandin is chemically related to well-known antimycotics, the echinocandins and pneumocandins, which are produced by such fungi as Zalerion arboricola, Pezicula spp. and Aspergillus spp. Cryptocandin has minimal inhibitory concentration values of 0.03-0.07 microgram ml-1 against isolates of Candida albicans, Trichophyton mentagrophytes and Trichophyton rubrum. Cryptocandin is also active against a number of plant-pathogenic fungi including Sclerotinia sclerotiorum and Botrytis cinerea.
TL;DR: In this paper, the existence and stability of stationary solutions of an integrodifferential model for phase transitions was studied, which is a gradient flow for a free energy functional with general nonlocal integrals penalizing spatial nonuniformity.
Abstract: We study the existence and stability of stationary solutions of an integrodifferential model for phase transitions, which is a gradient flow for a free energy functional with general nonlocal integrals penalizing spatial nonuniformity. As such, this model is a nonlocal extension of the AllenCahn equation, which incorporates long-range interactions. We find that the set of stationary solutions for this model is much larger than that of the AllenCahn equation.
TL;DR: It is unlikely that the entire decline in prostate cancer mortality can be explained by PSA testing based on current beliefs concerning lead time, and only very short lead times would produce a decline in mortality of the magnitude that has been observed.
Abstract: Background: The objective of this study was to investigate the circumstances under which dissemination of prostatespecific antigen (PSA) testing, beginning in 1988, could plausibly explain the declines in prostate cancer mortality observed from 1992 through 1994. Methods: We developed a computer simulation model by use of information on population-based PSA testing patterns, cancer detection rates, average lead time (the time by which diagnosis is advanced by screening), and projected decreased risk of death associated with early diagnosis of prostate cancer through PSA testing. The model provides estimates of the number of deaths prevented by PSA testing for the 7-year period from 1988 through 1994 and projects what prostate cancer mortality for these years would have been in the absence of PSA testing. Results: Results were generated by assuming a level of screening efficacy similar to that hypothesized for the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial. Under this assumption, the projected mortality in the absence of PSA testing continued the increasing trend observed before 1991 only when it was assumed that the mean lead time was 3 years or less. Projected mortality trends in the absence of PSA screening were not consistent with pre-1991 increasing trends for lead times of 5 years and 7 years. Conclusions: When screening is assumed to be at least as efficacious as hypothesized in the PLCO trial, it is unlikely that the entire decline in prostate cancer mortality can be explained by PSA testing based on current beliefs concerning lead time. Only very short lead times would produce a decline in mortality of the magnitude that has been observed. [J Natl Cancer Inst 1999;91:1033‐9]
01 Feb 1999
TL;DR: A reconfigurable architecture optimised for media processing, and based on 4-bit ALUs and interconnect, is described.
Abstract: In this paper we describe a reconfigurable architecture optimised for media processing, and based on 4-bit ALUs and interconnect.
TL;DR: In this paper, a discrete convolution model for Ising-like phase transitions is derived as an l 2-gradient flow for a Helmholtz free energy functional with general long range interactions.
Abstract: We study a discrete convolution model for Ising-like phase transitions. This nonlocal model is derived as an l
2-gradient flow for a Helmholtz free energy functional with general long range interactions. We construct traveling waves and stationary solutions, and study their uniqueness and stability. In particular, we find some criteria for “propagation” and “pinning”, and compare our results with those for a previously studied continuum convolution model.
TL;DR: It is asserted, long‐branch attraction cannot explain the presence of nematocysts in Myxozoa and halteres in Strepsiptera, and it is suggested that maximum likelihood methods are extremely sensitive to taxon and character sampling and that these data sets are demonstrative of the long-branch repulsion problem.
TL;DR: In this article, the problems associated with this narrow conceptualization of father involvement have been discussed, and a discussion of the problem associated with such a narrow conceptualisation can be found.
Abstract: Father involvement has been conceptualized and measured primarily as a temporal and directly observable phenomenon. This paper describes the problems associated with this narrow conceptualization a...
TL;DR: The current results suggest that language impairment is not the sole factor leading to social problems in children with LI, and assessment and intervention procedures for children with language and social problems should take the complex nature of this relationship into account.
Abstract: This study examined the dimensions of withdrawal and sociability in children with language impairment (LI) and their typically developing chronological age-matched peers. Classroom teachers rated t...
TL;DR: In this paper, the exact shape of the global bifurcation diagram is rigorously proved for a wide class of nonlinear functions ǫ(u)/ǫ.
21 Apr 1999
TL;DR: This paper describes the current status of a suite of CAD tools designed specifically for use by designers who are developing high-performance configurable-computing applications, including JHDL, which are being used successfully to implement high- performance applications in Automated Target Recognition (ATR), sonar beamforming, and general image processing on configured systems.
Abstract: This paper describes the current status of a suite of CAD tools designed specifically for use by designers who are developing high-performance configurable-computing applications. The basis of this tool suite is JHDL, a design tool originally conceived as a way to experiment with Run-Time Reconfigured (RTR) designs. However, what began as a limited experiment to model RTR designs with Java has evolved into a comprehensive suite of design tools and verification aids, with these tools being used successfully to implement high-performance applications in Automated Target Recognition (ATR), sonar beamforming, and general image processing on configurable-computing systems.
TL;DR: In this article, a nonlinear correlation has been developed that predicts the chemical structure parameters of both U.S. and non-U.S coals generally measured by 13C NMR and often required for advanced coal deformation models.
Abstract: 13C NMR spectroscopy has been shown to be an important tool in the characterization of coal structure. Important quantitative information about the carbon skeletal structure is obtained through 13C NMR spectral analysis of coal. Solid-state 13C NMR analysis techniques have progressed beyond the mere determination of aromaticity and can now describe features such as the number of aromatic carbons per cluster and the number of attachments per aromatic cluster. These 13C NMR data have been used to better understand the complicated structure of coal, to compare structural differences in coal, tar, and char, and to model coal devolatilization. Unfortunately, due to the expense of the process, extensive 13C NMR data are not available for most coals. A nonlinear correlation has been developed that predicts the chemical structure parameters of both U.S. and non-U.S. coals generally measured by 13C NMR and often required for advanced devolatilization models. The chemical structure parameters correlated include (i)...
TL;DR: Test results indicated that, at the genus level, both the classification key and discriminant analysis of certain morphotypes of phytoliths were relatively reliable tools for distinguishing among phylloliths produced in the inflorescence bracts of the taxa considered.
Abstract: Analysis of microfossil silica phytoliths is becoming an increasingly important research tool for taxonomists, archaeobotanists, and paleoecologists. Expanded use of phytolith analysis by researchers is dependent upon development of phytolith systematics. In this study phytoliths produced by the inflorescence bracts from four species of wheat, Triticum monoccocum, T. dicoccon, T. dicoccoides, and T. aestivum, and two species of barley, Hordeum vulgare, and H. spontaneum, were analyzed using computer-assisted image and statistical analysis with the intent to develop taxonomic tools to distinguish among the taxa. A classification key based on significant differences among the mean morphometries of the inflorescence phytoliths produced by each species was created and tested. Discriminant analysis of the morphometries of several morphotypes of phytoliths was also conducted to determine whether this computer-assisted statistical procedure could be used as another method to classify the taxa and to determine which morphotypes have measurements that can best be used in discriminant functions. Test results indicated that, at the genus level, both the classification key and discriminant analysis of certain morphotypes of phytoliths were relatively reliable tools for distinguishing among phytoliths produced in the inflorescence bracts of the taxa considered. For distinguishing among the taxa at the species level, the classification key was most reliable. Of the discriminant analyses tested, that based on all the phytolith morphotypes combined was more reliable than those based on only one morphotype.