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At least 19 recordsLinked to original sources
PubMed2002

Style and substance in psychology: are influential articles more readable than less influential ones?

The results from four studies are reported separately to test the idea that influential articles in psychology will be more readable than less influential ones. This idea is upheld when the papers involved are ones that have been highly rated by fellow colleagues (Studies 1 and 2) but it is not supported when the papers involved are highly-cited journal articles (Studies 3 and 4).

History, 20th Century↗
PubMed2002

Educationally influential physicians: the need for construct validation.

INTRODUCTION: Educationally influential physicians may be a valuable resource in continuing medical education. Although the idea driving this research--informal learning--converges with research in adult education, organizational learning, marketing, and knowledge diffusion, the results of interventions have proven inconclusive. To actualize the promise of the educationally influential physician (EIP) construct, it is argued that researchers must return to the "classic" studies in this area and resume the process of validating the meaning of the construct. METHODS: A literature review and the occasion of an educationally influential physician identification survey provided an opportunity to contribute to development of this construct. We compared three identification rules used to study 212 physicians. RESULTS: Each rule may identify different people as EIPs. DISCUSSION: To improve the use of educational influentials, research must be completed to validate their role in informal learning.

Adult↗
PubMed2001

Local influence to detect influential data structures for generalized linear mixed models.

This article discusses the generalization of the local influence measures for normally distributed responses to local influence measures for generalized linear models with random effects. For these models, it is shown that the subject-oriented influence measure is a special case of the proposed observation-oriented influence measure. A two-step diagnostic procedure is proposed. The first step is to search for influential subjects. A search for influential observations is proposed as the second step. An illustration of a two-treatment, multiple-period crossover trial demonstrates the practical importance of the detection of influential observations in addition to the detection of influential subjects.

Aspartame↗
PubMed2002

Genetic relationships and discrimination of ten influential Upland cotton varieties using RAPD markers.

Influential Upland cotton ( Gossypium hirsutum L.) varieties are those that have the higher genetic contributions to modern Upland cultivars than other germplasms. Our previous research has shown significant differences in general combining ability (GCA) effects for yield, yield components, and fiber properties among ten influential cotton varieties. In this study, we used random amplified polymorphic DNA (RAPD) data to evaluate DNA variation of these ten varieties. Of 86 random decamer primers screened for their capability of amplifying DNA via the polymerase chain reaction (PCR), 63 generated a total of 312 DNA fragments. Forty two bands were polymorphic, which showed a low percentage (13.5%) of DNA variation among these influential varieties. Genetic similarities among the ten varieties based on RAPD data were from 92.7% to 97.6%. All of the varieties were individually identified by variety specific markers in genetic fingerprinting. One primer, UBC-149, amplified a 1,430-bp DNA fragment that was absent in five varieties and present in the other five varieties. This RAPD marker had significant negative relationships with GCA-effect estimates for seed cotton yield, lint yield, number of bolls per plant and micronaire, and significant positive relationships with GCA effects for boll size and seed index. This finding, for the first time, identifies a DNA fragment in cotton that is a potential DNA marker linked to a yield gene(s) or a yield-related gene(s).

Journal Article↗
PubMed2002

Cross-validation by downweighting influential cases in structural equation modelling.

In the social and behavioural sciences, structural equation modelling has been widely used to test a substantive theory or causal relationship among latent constructs. Cross-validation (CV) is a valuable tool for selecting the best model among competing structural models. Influential cases or outliers are often present in practical data. Therefore, even the correct model for the majority of the data may not cross-validate well. This paper discusses various drawbacks of CV based on sample covariance matrices, and develops a procedure for using robust covariance matrices in the model calibration and validation stages. Examples illustrate that the CV index based on sample covariance matrices is very sensitive to influential cases, and even a single outlier can cause the CV index to support a wrong model. The CV index based on robust covariance matrices is much less sensitive to influential cases and thus leads to a more valid conclusion about the practical value of a model structure.

Behavioral Sciences↗
PubMed1998

[Identify influential points].

Influential points are the points with excessive influence on result and detected by influential function theta-theta(i). theta-theta(i) is a multidimensional vector. For convenience, people always consider some quantitative function g (theta-theta(i)) to measure the vector theta-theta(i), but how to define g is a difficult problem. This paper proposes a new quantitative diagnostic statistics for identifying influential points for all parametrical statistical analysis. The method is more appropriate than cook's method for regression analysis. In this study an example is used to illustrate the procedure in COX proportional hazard model.

Proportional Hazards Models↗
PubMed2000

Identifying educational influentials for formal and informal continuing medical education in the province of British Columbia.

BACKGROUND: The objective of this study was to identify physicians in the province of British Columbia (BC) who are perceived by their colleagues to be the most educationally influential. METHODS: A cross-sectional study using a previously validated survey tool was mailed to a randomly selected sample of 2300 BC registered primary care physicians. Follow-up mailings were sent to nonresponders. RESULTS: The survey response rate was 53%. A list of 375 educationally influential physicians (EIs) was proportionately determined and tabulated by region. IMPLICATIONS: The top 5% of provincial EIs were identified to serve as a resource for formal and informal continuing medical education (CME). Their names will be brought forward in response to selected requests for CME speakers.

Attitude of Health Personnel↗
PubMed1997

Glycosylation is influential in murine IgG3 self-association.

In mice and humans, antibodies of the IgG3 isotype are unique in that they spontaneously self-associate. A consequence is the formation of cryoglobulins from some, but not all IgG3 molecules. Little is known about the structural basis of murine IgG3 self-association. A region of the CH3 domain that is unique to IgG3 antibodies is the presence of an extra glycosylation site at residues 471-473. It is known that glycosylation greatly influences solubility. It has also been shown by X-ray crystallography that glycosylated residues (specifically sialic acid) are influential in the contacts of the CH1 to CH2 as well as the CH2 to CH2 domains in a human IgG1 antibody. These findings provided evidence that a direct interaction exists between the glycosylated residues and other residues within the constant and/or variable domains. It was, therefore, important to determine whether the glycosylated residue in the CH3 domain of the IgG3 constant region is influential in self-association. We have found that removing the glycosylation site by site-directed mutagenesis of an IgG3 RF significantly reduced the self-associating ability of this antibody.

Animals↗
PubMed2002

Ties to influential adults among black and white adolescents: culture, social class, and family networks.

Although prior research suggests the importance of nonparental adults to adolescents, the ecological context of those relationships has received little attention. This study examined ties to influential adults among 122 adolescents who varied by race, family structure, and gender The strongest effects were for race. Blacks reported stronger ties than Whites to the maternal grandmother as well as more supportive interactions with adult males. While race differences in grandparental ties were robust across social class (SES), ties to an influential adult male became nonsignificant upon controlling for SES. African American girls from divorced families consistently reported the strongest ties. Discussion considers the role of culture versus SES in explaining race differences. Implications for mentoring interventions are proposed, with special attention to the role of actualizing latent ties to already existing network members.

Adolescent↗
PubMed1994

The psychological development of children of epileptic parents. II. The differential impact of intrauterine exposure to anticonvulsant drugs and further influential factors.

After obtaining evidence that tetratogenic effects were operant in a sample of children born to epileptic mothers, we analyzed the effects of type of medication and further influential factors. Children with prenatal exposure to polytherapy had significantly lower scores than controls for a large number of psychological tests. In addition to polytherapy, there were even stronger effects of socioeconomic status and sex was found to be less influential than polytherapy. Among further epilepsy variables, only seizure frequency of the mother during pregnancy had a modest impact on the child's developmental outcome, whereas a score of obstetric abnormality was less effective in predicting developmental outcome, as measured and defined by various standardized psychological tests.

Age Factors↗
PubMed2000

[Influential factors on health-related quality of life after cerebral vascular disease].

A mail survey was conducted to elucidate the influential factors on heath-related quality of life (HRQOL) after cerebral vascular disease. Questionnaires for clinicians and their patients were mailed to 2,587 hospitals with more than 100 beds, which have at least one of the following departments: neurosurgery, neurology, psychiatry or rehabilitation. Each mailing contained a request to the clinician and questionnaires for 5 cases. 378 effective questionnaires could be collected, meaning the collection rate was 2.9%. The questions for the physicians concerned diagnosis (cerebral infarction or hemorrhage), duration of illness, activities of daily living(ADL), manifestation of paralysis and psychiatric symptoms and so forth. The questionnaire for the patients was composed of items from the EuroQol clinical version (EuroQol). Geriatric Depression Scale short form (GDS) and inquiries concerning family living with the patients, their housekeeping and so on. A visual analogue scale (VAS) concerning health state of the EuroQol was used as a measure of HRQOL. Coefficients of determination between VAS and other inquiries were calculated by regression analysis or ANOVA, revealing that "anxiety/depression", "GDS" and 16 other items were statistically significant on VAS (p < 0.05). General linear model (GLM) analysis using VAS as a criterion variable and these 18 items as predictor variables showed that "sleep disturbance" and GDS score were most influential on VAS according to the F value of the type 3 sum of squares. "Health state today compared to that during the past one year", "shopping as housekeeping", "ADL" and "pain/discomfort" also have some influence on VAS. In conclusion, sleep disturbance and depression had the most deleterious effect on HRQOL.

Aged↗
PubMed1999

Reductive half-reaction of the H172Q mutant of trimethylamine dehydrogenase: evidence against a carbanion mechanism and assignment of kinetically influential ionizations in the enzyme-substrate complex.

The reactions of wild-type trimethylamine dehydrogenase (TMADH) and of a His-172-->Gln (H172Q) mutant were studied by rapid-mixing stopped-flow spectroscopy over the pH range 6.0-10.5, to address the potential role of His-172 in abstracting a proton from the substrate in a 'carbanion' mechanism for C-H bond cleavage. The pH-dependence of the limiting rate for flavin reduction (klim) was studied as a function of pH for the wild-type enzyme with perdeuterated trimethylamine as substrate. The use of perdeuterated trimethylamine facilitated the unequivocal identification of two kinetically influential ionizations in the enzyme-substrate complex, with macroscopic pKa values of 6.5+/-0.2 and 8.4+/-0.1. A plot of klim/Kd revealed a bell-shaped curve and two kinetically influential ionizations with macroscopic pKa values of 9.4+/-0.1 and 10.5+/-0.1. Mutagenesis of His-172, a potential active-site base and a component of a novel Tyr-His-Asp triad in the active site of TMADH, revealed that the pKa of 8.4+/-0.1 for the wild-type enzyme-substrate complex represents ionization of the imidazolium side-chain of His-172. H172Q TMADH retains catalytic competence throughout the pH range investigated. At pH 10.5, and in contrast with the wild-type enzyme, flavin reduction in H172Q TMADH is biphasic. The fast phase is dependent on the trimethylamine concentration and exhibits a kinetic isotope effect of about 3; C-H bond cleavage is thus partially rate-limiting. In contrast, the slow phase does not show hyperbolic dependence on substrate concentration, and the observed rate shows no dependence on isotope, revealing that C-H bond cleavage is not rate-limiting. The analysis of H172Q TMADH, together with data recently acquired for the Y169F mutant of TMADH, reveals that C-H bond breakage is not initiated via abstraction of a proton from the substrate by an active-site base. The transfer of reducing equivalents to flavin via a carbanion mechanism is therefore unlikely.

Enzyme Activation↗
PubMed2002

[Characteristics of forms of fluorine in soils and influential factors].

Forms of fluorine in 15 different soils were studied using sequential chemical extraction procedure. The fluoride forms in soils were separated into five fractions: water soluble fluoride (Ws-F), exchangeable fluoride (Ex-F), fluoride bound to Fe/Mn oxides (Fe/Mn-F), bound to organic matter (Or-F), and residual fluoride (Residual-F). The contents of different fluoride forms were decreased in the order: Residual-F >> Ex-F > Ws-F > Or-F > AoFe-F. Correlation analyses showed that Ws-F was significantly correlated with Ex-F (r = 0.775* *). Ex-F was correlated with Fe/Mn-F (r = 0.5753*) and Organic-F (r = 0.5529*). Stepwise linear regression analysis was used to test the effect of various soil components on the contribution of fluoride forms, indicating that soil pH, organic matter, clay content, and exchangeable calcium content were the important influential factors and pH was the most important influential factor. In addition, soil parent materials had also influence on forms of fluorine.

Fluorine↗
PubMed1985

Influential factors in recruitment and retention of minority students in a community college.

To alleviate the problem of underrepresentation of minorities in allied health professions, colleges are encouraged to target and strengthen their recruitment and retention programs. The two-year college is often cited as the major entry point into higher education for minority students. To determine effective ways in which retention and recruitment programs could be enhanced in two-year colleges, the most influential and least influential factors were determined through a survey of successful minority graduates of allied health programs in a large two-year college. Certain results contradict what generally has been associated with successful recruitment and retention of minorities. Findings suggest that colleges begin closely examining what is occurring within their respective institutions to determine which factors could be having a positive, as well as negative, impact upon recruitment and retention of minorities. This study also suggests that student perception could be a valuable source of information.

Allied Health Personnel↗
PubMed1998

A simple method for visualization of influential landmarks when using euclidean distance matrix analysis.

Euclidean distance matrix analysis (EDMA) differs from most other morphometric methods for the analysis of landmark coordinate data in that it is coordinate-system invariant. However, strict adherence to coordinate-system invariance (for both biological and statistical reasons) introduces some difficulty in using graphic aids for the analysis and interpretation of EDMA results. We present a simple and effective graphic method to help localize important differences in form, growth, or shape by identifying "influential" landmarks. Examples are presented using simulated data and real data involving both children with craniofacial dysmorphologies and sexual dimorphism in adult Macaca fascicularis.

Acrocephalosyndactylia↗
PubMed1992

On comparing biological shapes: detection of influential landmarks.

For problems of classification and comparison in biological research, the primary focus is on the similarity of forms. A biological form consists of size and shape. Several approaches for comparing biological forms using landmark data are available. If the two biological forms are demonstrated to be different, the next important issue is to localize the differences by identifying those areas which differ most between the two objects. In this paper we suggest a technique to detect influential landmarks, those which contribute most to the difference between forms. We study the effectiveness of the technique using three-dimensional simulated data sets and two examples. Results suggest that the technique is useful in the study of biological form and its variation.

Acrocephalosyndactylia↗
PubMed2001

Nonparametric linkage regression. II: Identification of influential pedigrees in tests for linkage.

We applied case-deletion-based diagnostics to the combined Caucasian genome scan data for asthma and IgE from the Collaborative Study on the Genetics of Asthma (CSGA) and German family studies in order to identify influential pedigrees in tests for linkage. These methods identified 12 pedigrees whose data appear not to fit the asthma linkage model and for whom alternative genetic and nongenetic explanations can be explored. The methods also identified four pedigrees for chromosome 1 and two pedigrees for chromosome 2 that provide strong evidence for linkage at their respective loci. Similarly, these methods helped identify four pedigrees that strongly influenced the linkage tests for IgE. From these data, we can construct an enriched subset of pedigrees to be used in further analysis for mapping region-specific putative trait predisposing loci.

Adult↗
PubMed1992

The effect of influential outliers on parameter estimation in regression analysis.

A comment is made on an article recently published in this journal by Borgeat, Elie, and Castonguay (1991). It is noted that the raw data contained an outlier which is shown to have had a large influence on their estimation of the regression coefficient. Analysis of the data using a nonparametric statistic that is optimal for long-tailed distributions showed that the true regression coefficient is probably smaller than that reported. Other approaches to the analysis of data containing influential outliers are discussed.

Biofeedback, Psychology↗