1,721,037 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
The relationship of socioeconomic status to the prevalence of dental caries and fluorosis in the elementary schoolchildren of Genesee County, Michigan.
No full textSocioeconomic status (SES) in the United States is based on education, income, gender, race and ethnicity. There is evidence to suggest that SES is associated with dental caries and fluorosis, however the limited number of studies to date have used questionable study designs and have inconsistently controlled for important covariates. The purpose of this study is to assess the relationships of SES to prevalence and severity of dental caries and prevalence of fluorosis using a more appropriate study design and statistical analyses. This investigation used data from the Genesee County Oral Health Project, a cross-sectional study involving an oral screening examination and a telephone interview of a representative sample of 1st- and 4th-grade elementary schoolchildren in Genesee County, Michigan. Covariates included access to care, demographics, dental behaviors, dental knowledge, dental factors, and miscellaneous factors. Weighted bivariate and multivariate analyses were conducted using SAS and SUDAAN statistical software packages. SES was inversely related to dental caries prevalence and severity, and directly related to prevalence of fluorosis. Significant SES variables were occupation, level of education, presence of health insurance and Medicaid, crowded living conditions, and family income. One versus two parents or guardians, presence of dental insurance, and eligibility for reduced-fee meals at school were not significantly related to the outcomes. The association of each SES indicator depended upon the outcome (dental caries versus fluorosis), the component part of the outcome (DS+ds, FS+fs, and DMFS+dfs), and the representation of the outcome (prevalence, severity type I, and severity type II). Two possible indirect pathways through which the SES variables imparted an effect on dental caries and fluorosis were oral health care utilization and dental knowledge. Future studies should assess: (1) why different measures of SES were related to different components of the outcomes, (2) how SES imparted an indirect effect via utilization and dental knowledge, and what effect SES would have on the outcomes in different study settings.Doctor of Public Health (DPH)DentistryHealth and Environmental SciencesPublic healthPublic policySocial SciencesSocial structureUniversity of Michigan, Horace H. Rackham School of Graduate Studies, School of Public Healthhttp://deepblue.lib.umich.edu/bitstream/2027.42/131369/2/9908031.pd
Changes in disparities in dental caries experiences in United States adults.
No full textDisparities in dental caries experience and other health outcomes have long been reported to exist across age, race, and socioeconomic strata in the United States. The purpose of the study was to determine whether the disparities in the DMFT scores (Decayed, Missing and Filled teeth) among birth cohorts of the different age, race, and socioeconomic U.S. adult population groups changed between National Health and Nutrition Examination Survey (NHANES I) and NHANES III. The study used a cohort analytic method which followed cohorts, tracking changes in dental caries experience over the study period, as an alternative to the cross-sectional comparisons traditionally used to demonstrate disparity changes in caries experience. Data from the NHANES I and NHANES III were used for secondary data analysis. The disparity between individuals with at least 12 years of education and those with fewer than 12 years of education in the mean number of untreated carious teeth and missing teeth decreased by 42 percent and 72 percent respectively. The disparity in the mean number of filled teeth between individuals with at least 12 years of education and those with fewer than 12 years of education increased by 34 percent. The disparity between African Americans and whites in the mean number of untreated carious teeth and filled teeth decreased by 56 percent and 15 percent respectively. There was no significant disparity in the mean number of missing teeth between African Americans and whites at NHANES I, but by NHANES III, African Americans had on average 2.22 (p < 0.001) more missing teeth. Though African Americans had higher percentage increases in DMFT for both levels of education, whites had higher DMFT scores at the time of NHANES I and NHANES III than the African Americans. Overall the effect of education was more significant among whites than among African American during the study period. In conclusion, there were both reductions and increases in absolute disparities in caries experience among birth cohorts of the different racial and socioeconomic U.S. adult population groups between NHANES I and NHANES III. Depending on the groups being compared some disparities were reduced while others were increased. The study will help in better understanding the distribution of caries experience in the United States population.PhDBlack studiesDentistryHealth and Environmental SciencesPublic healthSocial SciencesUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/123440/2/3079494.pd
Non-insulin-dependent diabetes mellitus and adult periodontitis in the Gila River Indian Community.
No full textThe purpose of this study was to analyze the relationships among non-insulin-dependent diabetes mellitus (NIDDM), periodontitis, and tooth loss, using longitudinal data collected in the Gila River Indian Community, AZ. Three sets of hypotheses were tested: (1) the association of NIDDM with the occurrence of adult periodontitis, partial tooth loss and edentulism; (2) the association of NIDDM with the progression of periodontitis; and (3) the relationship between periodontitis and glycemic control. Methods for testing these hypotheses included stratified contingency table analysis, logistic regression models, using both dichotomous and polytomous response variable formulations, and generalized estimating equations, using dichotomous responses. Dependent variables included measures of incidence and progression of periodontitis and incidence of partial tooth loss, complete edentulism, and poor glycemic control. The principal exposure was glucose tolerance status, using a dichotomous specification separating subjects with NGT/IGT from those with NIDDM. Covariates assessed for confounding and effect modification included: variables relating to the presence, severity, duration, and degree of control of diabetes; diabetes specific complications and other concomitant systemic conditions; selected demographic and health-related behavioral variables; and measures of oral hygiene. These analyses applied stringent selection criteria, including only subjects whose glucose tolerance status remained unchanged over the period of observation. For analyses involving measures of adult periodontitis, subjects who lost teeth between examinations were excluded. This study concludes that NIDDM is associated with increased risk of: (a) occurrence and more severe progression of adult periodontitis, (b) partial tooth loss, and (c) complete edentulism. These risks may be modified by baseline age, number of teeth or periodontal status. There was insufficient evidence to conclude that an association between baseline complications of NIDDM and increased risk for progression of periodontitis exists. The analyses suggest, however, that the incidence of diabetes-specific complications, poor glycemic control, and more severe NIDDM are associated with increased risk for the progression of periodontitis. Finally, the analyses suggest there is an association between severe periodontitis and increased risk for poor glycemic control.Doctor of Public Health (DPH)Dental Public HealthUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/103879/1/9417113.pdfDescription of 9417113.pdf : Restricted to UM users only
Oral Chlamydia trachomatis in a dental clinic population with established periodontitis.
No full textChlamydia trachomatis is an intracellular pathogen of mucosal epithelial cells lining the ocular, nasopharyngeal, and uro-genital tracts. C. trachomatis causes trachoma the leading cause of preventable blindness and the most common bacterial sexually transmitted disease in the United States. Because of some similarities between the natural history of C. trachomatis infections and periodontitis, it was hypothesized that C. trachomatis would be found in the lining epithelium of periodontal sites diagnosed as having periodontitis. The purpose of this study was to assess oral epithelial cell specimens for the presence of C. trachomatis. Participants were dental clinic patients (n = 87) aged 18-50 years with no history of systemic disease associated with neutrophil disorders and who had not taken antibiotics indicated for C.trachomatis treatment in the previous three months. Participants needed to have at least three teeth which satisfied the definition for established periodontitis and also at least three teeth which were considered periodontally healthy. Pooled cell specimens were made for each participant from three locations; the diseased periodontal sites, the healthy periodontal sites, and a general mucosal site which included the lining of the cheeks, floor of mouth and tongue. For cell collection a periodontal probe was wiped against the lining epithelium at the periodontal sites and a cytobrush was brushed against the general mucosal tissue. Microslide cell specimens were prepared using the Behring Diagnostic MicroTrak\sp\circler Chlamydia trachomatis Direct Specimen Test for direct immunofluorescence technique. Cross-reactivity of the commercial monoclonal antibody was tested with twenty microorganisms including fourteen dental plaque microorganisms, e.g. Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, and Bacteroides forsythus. This study found six participants (6.9%) positive for C. trachomatis in oral specimens. C. trachomatis was detected in the diseased periodontal sites in four participants, in the healthy periodontal sites in one participant and from the general mucosal site of another. All tests for cross-reactivity were negative. The discovery of C. trachomatis in the lining epithelium of the periodontal sulci generates many questions concerning its role in periodontitis. Also, whether or not the oral cavity is a reservoir for C. trachomatis is important for transmission, treatment, and prevention issues.Doctor of Public Health (DPH)Dental Public HealthUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/105057/1/9626023.pdfDescription of 9626023.pdf : Restricted to UM users only
Fluid consumption and fluoride intake among children in the United States: Implications for water fluoridation *policy.
No full textCurrent standards for water fluoridation in the U.S. have stood since 1962. Research on which current public policy is based was conducted in the 1940s and 50s. Since the 1980s, declines in dental caries and an increase in dental fluorosis have been observed. The literature indicates that children today are ingesting more fluoride than in the past. This dissertation aimed to evaluate assumptions pertaining to water fluoridation, with a focus on the fluid consumption among children in the U.S. Specific aims are: (1) to evaluate the relationship between fluid consumption among children and local climate, (2) to investigate the relationship of fluid consumption patterns and sociodemographic factors, (3) to estimate fluoride intake and to identify population groups with a risk of high fluoride intake, based on the fluid consumption patterns. A secondary analysis of data from the Third National Health and Nutrition Examination Survey (NHANES III, 1988--1994) was conducted. Fluid consumption data was from a 24-hour dietary recall survey. Data for local climate from the US National Climatic Data Center was incorporated. Cluster analysis was conducted using SAS to determine fluid consumption patterns. Fluoride intake was estimated using assumptions of fluoride concentrations in drinking water and beverages. SUDAAN was used to adjust standard errors for the complex sampling design. This dissertation found that; (1) there is no evidence that fluid consumption is significantly related to local climate in modern conditions, (2) age, sex, race/ethnicity, and SES are significantly associated with children's fluid consumption patterns, (3) the amount of fluoride intake may vary greatly depending on fluid consumption patterns and sociodemographic characteristics. From the results, it is suggested that; (1) the current national temperature-related guidelines for fluoride concentration in drinking water may be due for re-evaluation, (2) fluid consumption patterns and sociodemographic factors should be considered in future research and public policy making for fluoride use, (3) the possibility of additional risk of fluorosis with supplement use should be recognized, and (4) a regulation to require the labeling of the fluoride content in beverages would help parents and health care providers to make informed decisions on their children's risk of fluorosis.Doctor of Public Health (DPH)DentistryHealth and Environmental SciencesPublic administrationPublic healthSocial SciencesUniversity of Michigan, Horace H. Rackham School of Graduate Studies, School of Public Healthhttp://deepblue.lib.umich.edu/bitstream/2027.42/132523/2/9974997.pd
The relationship between oral health status and systemic biomarkers.
No full textEpidemiological and clinical studies investigating the association between periodontal disease (PD) and cardiovascular disease (CVD) often implicate the potential role of elevated serum inflammatory markers (IM). However, the relationship between PD and elevated oral and systemic IM is not clearly understood. Objectives. The purpose of this prospective, longitudinal human cohort study was to assess the impact of oral health status and dental treatment on baseline levels and longitudinal changes in oral and systemic IM in adults. Methods. 30 persons aged 29--74 years (55 +/- 11 yrs; mean +/- SD) with terminal dentition (TD; i.e., severe periodontal disease requiring full mouth extraction of at least 8 teeth) and 26 persons aged 31--83 years (54 +/- 13 yrs) who were periodontally healthy (PH; no probing depths >4mm) were recruited at the UNC School of Dentistry. Serum and gingival crevicular fluid (GCF) were collected at baseline, and 2-, 6-, 13-, 26-, and 52-weeks post-baseline for assessment of inflammatory and associated systemic markers including serum C-reactive protein, interleukin-6, lipid panel, complete blood count, and others. Student's t-test was used to test group and visit differences. Additional linear regression and mixed model analysis evaluated several variables individually with the group and visit effects. These variables included age, gender, race/ethnicity, body mass index, smoking status, and other systemic risk factors. Results: Baseline mean GCF Interleukin-1beta and PGE 2, and serum Interleukin-6 were significantly elevated in the TD compared to PH group. This relationship was unchanged following bivariate adjustment for known risk factors. A trend was observed for elevated baseline median CRP in the TD group. Mean IL-6 was consistently significantly lower and apolipoprotein A was consistently significantly higher than at baseline following extractions. Conclusions: These results suggest that TD status and treatment may be associated with a difference and subsequent change in some oral and systemic inflammatory markers independent of known risk factors. However, larger studies are needed to adequately test this hypothesis. This study was supported by National Institutes of Health, National Institute of Dental and Craniofacial Research grants DE00427 and DE013079.PhDDentistryHealth and Environmental SciencesPublic healthUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/124794/2/3163803.pd
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