Spatial prediction of Plasmodium falciparum prevalence in Somalia

Directory of Open Access Journals (Sweden)

Shewchuk Tanya

2008-08-01

Full Text Available Abstract Background Maps of malaria distribution are vital for optimal allocation of resources for anti-malarial activities. There is a lack of reliable contemporary malaria maps in endemic countries in sub-Saharan Africa. This problem is particularly acute in low malaria transmission countries such as those located in the horn of Africa. Methods Data from a national malaria cluster sample survey in 2005 and routine cluster surveys in 2007 were assembled for Somalia. Rapid diagnostic tests were used to examine the presence of Plasmodium falciparum parasites in finger-prick blood samples obtained from individuals across all age-groups. Bayesian geostatistical models, with environmental and survey covariates, were used to predict continuous maps of malaria prevalence across Somalia and to define the uncertainty associated with the predictions. Results For analyses the country was divided into north and south. In the north, the month of survey, distance to water, precipitation and temperature had no significant association with P. falciparum prevalence when spatial correlation was taken into account. In contrast, all the covariates, except distance to water, were significantly associated with parasite prevalence in the south. The inclusion of covariates improved model fit for the south but not for the north. Model precision was highest in the south. The majority of the country had a predicted prevalence of Conclusion The maps showed that malaria transmission in Somalia varied from hypo- to meso-endemic. However, even after including the selected covariates in the model, there still remained a considerable amount of unexplained spatial variation in parasite prevalence, indicating effects of other factors not captured in the study. Nonetheless the maps presented here provide the best contemporary information on malaria prevalence in Somalia.

A modified approach to estimating sample size for simple logistic regression with one continuous covariate.

Science.gov (United States)

Novikov, I; Fund, N; Freedman, L S

2010-01-15

Different methods for the calculation of sample size for simple logistic regression (LR) with one normally distributed continuous covariate give different results. Sometimes the difference can be large. Furthermore, some methods require the user to specify the prevalence of cases when the covariate equals its population mean, rather than the more natural population prevalence. We focus on two commonly used methods and show through simulations that the power for a given sample size may differ substantially from the nominal value for one method, especially when the covariate effect is large, while the other method performs poorly if the user provides the population prevalence instead of the required parameter. We propose a modification of the method of Hsieh et al. that requires specification of the population prevalence and that employs Schouten's sample size formula for a t-test with unequal variances and group sizes. This approach appears to increase the accuracy of the sample size estimates for LR with one continuous covariate.

Anisometropia prevalence in a highly astigmatic school-aged population.

Science.gov (United States)

Dobson, Velma; Harvey, Erin M; Miller, Joseph M; Clifford-Donaldson, Candice E

2008-07-01

To describe prevalence of anisometropia, defined in terms of both sphere and cylinder, examined cross-sectionally, in school-aged members of a Native American tribe with a high prevalence of astigmatism. Cycloplegic autorefraction measurements, confirmed by retinoscopy and, when possible, by subjective refraction were obtained from 1041 Tohono O'odham children, 4 to 13 years of age. Astigmatism > or =1.00 diopter (D) was present in one or both eyes of 462 children (44.4%). Anisometropia > or =1.00 D spherical equivalent (SE) was found in 70 children (6.7%), and anisometropia > or =1.00 D cylinder was found in 156 children (15.0%). Prevalence of anisometropia did not vary significantly with age or gender. Overall prevalence of significant anisometropia was 18.1% for a difference between eyes > or =1.00 D SE or cylinder. Vector analysis of between-eye differences showed a prevalence of significant anisometropia of 25.3% for one type of vector notation (difference between eyes > or =1.00 D for M and/or > or =0.50 D for J0 or J45), and 16.2% for a second type of vector notation (between-eye vector dioptric difference > or =1.41). Prevalence of SE anisometropia is similar to that reported for other school-aged populations. However, prevalence of astigmatic anisometropia is higher than that reported for other school-aged populations.

Prevalence and incidence of memory complaints in employed compared to non-employed aged 55-64 years and the role of employment characteristics.

Directory of Open Access Journals (Sweden)

Kelly J Rijs

Full Text Available To examine the association of employment status and characteristics with prevalent and incident memory complaints (MC in 55-64-year-olds.Subjects were participants of the Longitudinal Aging Study Amsterdam (LASA. Respondents with baseline data were selected to examine the association of employment status (n = 1525 and employment characteristics (n = 1071 with prevalent MC (i.e., MC at baseline. Respondents without MC at baseline were selected to examine the association of employment (n = 526 and employment characteristics (n = 379; working hours, job prestige, job level, psychological job demands, iso-strain with incident MC (i.e., no MC at baseline and MC at three-year follow-up. Associations were adjusted for relevant covariates (demographics, memory performance, physical health, mental health, personality traits. Logistic regression was applied. Data were weighed according to gender and age of the Dutch population.At baseline 20.5% reported MC. At three-year follow-up, 15.4% had incident MC. No associations were found between employment status and MC. Adjusted analysis revealed that individuals with high occupational cognitive demands were more likely to have prevalent MC.Middle-aged workers are equally as likely to experience MC as non-working age-peers. Among workers, those with cognitively demanding work were more likely to experience MC, independent of memory performance. Memory decline due to ageing may be noticed sooner in 55-64-year-olds performing cognitively demanding work.

Covariate-adjusted measures of discrimination for survival data

DEFF Research Database (Denmark)

White, Ian R; Rapsomaniki, Eleni; Frikke-Schmidt, Ruth

2015-01-01

by the study design (e.g. age and sex) influence discrimination and can make it difficult to compare model discrimination between studies. Although covariate adjustment is a standard procedure for quantifying disease-risk factor associations, there are no covariate adjustment methods for discrimination...... statistics in censored survival data. OBJECTIVE: To develop extensions of the C-index and D-index that describe the prognostic ability of a model adjusted for one or more covariate(s). METHOD: We define a covariate-adjusted C-index and D-index for censored survival data, propose several estimators......, and investigate their performance in simulation studies and in data from a large individual participant data meta-analysis, the Emerging Risk Factors Collaboration. RESULTS: The proposed methods perform well in simulations. In the Emerging Risk Factors Collaboration data, the age-adjusted C-index and D-index were...

Covariance NMR Processing and Analysis for Protein Assignment.

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Harden, Bradley J; Frueh, Dominique P

2018-01-01

During NMR resonance assignment it is often necessary to relate nuclei to one another indirectly, through their common correlations to other nuclei. Covariance NMR has emerged as a powerful technique to correlate such nuclei without relying on error-prone peak peaking. However, false-positive artifacts in covariance spectra have impeded a general application to proteins. We recently introduced pre- and postprocessing steps to reduce the prevalence of artifacts in covariance spectra, allowing for the calculation of a variety of 4D covariance maps obtained from diverse combinations of pairs of 3D spectra, and we have employed them to assign backbone and sidechain resonances in two large and challenging proteins. In this chapter, we present a detailed protocol describing how to (1) properly prepare existing 3D spectra for covariance, (2) understand and apply our processing script, and (3) navigate and interpret the resulting 4D spectra. We also provide solutions to a number of errors that may occur when using our script, and we offer practical advice when assigning difficult signals. We believe such 4D spectra, and covariance NMR in general, can play an integral role in the assignment of NMR signals.

Age-specific prevalence of human papilloma virus infection among Nigerian women.

Science.gov (United States)

Akarolo-Anthony, Sally N; Famooto, Ayo O; Dareng, Eileen O; Olaniyan, Olayinka B; Offiong, Richard; Wheeler, Cosette M; Adebamowo, Clement A

2014-06-27

Inconsistent trends in HPV prevalence by age have been described in Africa. We examined the age prevalence pattern and distribution of 37 HPV-DNA types among urban Nigerian women. The study population was a sample of 278 women who presented to cervical cancer screening programs in Abuja, Nigeria, between April and August 2012. Using a nurse administered questionnaire, information on demographic characteristics and risk factors of cervical cancer was collected and samples of cervical exfoliated cells were obtained from all participants. Roche Linear Array HPV Genotyping Test® was used to characterize prevalent HPV and log-binomial regression models were used to examine the association between potential correlates and the prevalence of HPV infection. The mean age (SD) of the women enrolled was 38 (8) years. The overall prevalence of HPV was 37%. HPV 35 was the most prevalent HPV type in the study population. Among women age ≤ 30 years, 52% had HPV infection compared to 23% of those women who were older than 45 years (p = 0.006). We observed a significant linear association between age and the prevalence of HPV infections. The prevalence ratio (PR) and 95% confidence interval (CI) was 2.26 (1.17, 4.34) for any HPV infection, 3.83 (1.23, 11.94) for Group 1 HPV (definite carcinogens), and 2.19 (0.99, 4.84) for Group 2a or 2b HPV (probable or possible carcinogens) types, among women aged 18-30 years, compared to women who were older than 45 years. The prevalence of HPV infection was highest among younger women and decreased steadily with age among this population of urban Nigerian women.

Prevalence of Age-Related Macular Degeneration in Europe

NARCIS (Netherlands)

Colijn, Johanna M.; Buitendijk, Gabriëlle H. S.; Prokofyeva, Elena; Alves, Dalila; Cachulo, Maria L.; Khawaja, Anthony P.; Cougnard-Gregoire, Audrey; Merle, Bénédicte M. J.; Korb, Christina; Erke, Maja G.; Bron, Alain; Anastasopoulos, Eleftherios; Meester-Smoor, Magda A.; Segato, Tatiana; Piermarocchi, Stefano; de Jong, Paulus T. V. M.; Vingerling, Johannes R.; Topouzis, Fotis; Creuzot-Garcher, Catherine; Bertelsen, Geir; Pfeiffer, Norbert; Fletcher, Astrid E.; Foster, Paul J.; Silva, Rufino; Korobelnik, Jean-François; Delcourt, Cécile; Klaver, Caroline C. W.; Ajana, Soufiane; Arango-Gonzalez, Blanca; Arndt, Verena; Bhatia, Vaibhav; Bhattacharya, Shomi S.; Biarnés, Marc; Borrell, Anna; Bühren, Sebastian; Calado, Sofia M.; Cougnard-Grégoire, Audrey; Dammeier, Sascha; de Jong, Eiko K.; de la Cerda, Berta; den Hollander, Anneke I.; Diaz-Corrales, Francisco J.; Diether, Sigrid; Emri, Eszter; Endermann, Tanja; Ferraro, Lucia L.; Garcia, Míriam; Heesterbeek, Thomas J.; Honisch, Sabina; Bergen, Arthur

2017-01-01

Purpose: Age-related macular degeneration (AMD) is a frequent, complex disorder in elderly of European ancestry. Risk profiles and treatment options have changed considerably over the years, which may have affected disease prevalence and outcome. We determined the prevalence of early and late AMD in

Prevalence of Age-Related Macular Degeneration in Europe

DEFF Research Database (Denmark)

Colijn, Johanna M; Buitendijk, Gabriëlle H S; Prokofyeva, Elena

2017-01-01

PURPOSE: Age-related macular degeneration (AMD) is a frequent, complex disorder in elderly of European ancestry. Risk profiles and treatment options have changed considerably over the years, which may have affected disease prevalence and outcome. We determined the prevalence of early and late AMD...

Prevalence and covariates of food insecurity among residents of single-room occupancy housing in Chicago, IL, USA.

Science.gov (United States)

Bowen, Elizabeth A; Bowen, Sarah K; Barman-Adhikari, Anamika

2016-04-01

Emerging evidence suggests that food insecurity is a significant public health concern among people who are homeless or marginally housed. The present study assessed prevalence of food insecurity and its covariates among a group of marginally housed individuals living in single-room occupancy (SRO) dwellings, a population for which there is little extant health or nutrition research. Cross-sectional survey incorporating the Household Food Insecurity Access Scale. Ten private SRO residences in the Uptown neighbourhood of Chicago, IL, USA, 2013. SRO residents over 18 years of age who were able to communicate verbally in English (n 153). Food insecurity was widespread among SRO residents, with 75 % of the sample considered food insecure and 52 % meeting criteria for severe food insecurity. Bivariate analyses indicated that female gender, eating most meals at a soup kitchen, having a mental health condition, problem drinking, having at least one chronic health condition, and diabetes were all significantly associated with food insecurity. In the multivariate ordered logistic regression model, eating most meals at a soup kitchen remained as the only significant correlate of food insecurity (OR=10·13). SRO residents and other marginally housed populations face unique food access challenges. Although targeted assistance in the form of food stamps and congregate meal programmes remains critical, efforts to prevent and address food insecurity among homeless and marginally housed individuals should include policy interventions that recognize poverty as the root cause of food insecurity and aim to increase overall income and improve housing conditions.

The prevalence and age distribution of peripheral pulmonary ...

African Journals Online (AJOL)

This autopsy-based study defined the prevalence and age distribution of peripheral pulmonary hamartomas in 47635 southern African miners examined between 1975 and 1988. The prevalence rate for white miners was 7,5/1000 and for black miners 1,1/1 000. When directly standardised to the white men in the general ...

Autism Prevalence Trends Over Time in Denmark: Changes in Prevalence and Age at Diagnosis

DEFF Research Database (Denmark)

Parner, Erik; Schendel, Diana; Thorsen, Poul

2008-01-01

OBJECTIVE: To examine the effect of changing age at diagnosis on the diagnosed prevalence of autism among different birth cohorts. DESIGN: Population-based cohort study. SETTING: Children were identified in the Danish Medical Birth Registry and psychiatric outcomes were obtained via linkage...... risk comparing the 1998-1999 birth cohort with the 1994-1995 birth cohort at age 3 years was 1.69 (95% CI, 1.24-2.31), which decreased to 1.23 (95% CI, 1.11-1.37) at age 11 years. Similar results were observed for childhood autism. CONCLUSIONS: Shifts in age at diagnosis inflated the observed...... prevalence of autism in young children in the more recent cohorts compared with the oldest cohort. This study supports the argument that the apparent increase in autism in recent years is at least in part attributable to decreases in the age at diagnosis over time....

The association between major depression prevalence and sex becomes weaker with age.

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Patten, Scott B; Williams, Jeanne V A; Lavorato, Dina H; Wang, Jian Li; Bulloch, Andrew G M; Sajobi, Tolulope

2016-02-01

Women have a higher prevalence of major depressive episodes (MDE) than men, and the annual prevalence of MDE declines with age. Age by sex interactions may occur (a weakening of the sex effect with age), but are easily overlooked since individual studies lack statistical power to detect interactions. The objective of this study was to evaluate age by sex interactions in MDE prevalence. In Canada, a series of 10 national surveys conducted between 1996 and 2013 assessed MDE prevalence in respondents over the age of 14. Treating age as a continuous variable, binomial and linear regression was used to model age by sex interactions in each survey. To increase power, the survey-specific interaction coefficients were then pooled using meta-analytic methods. The estimated interaction terms were homogeneous. In the binomial regression model I (2) was 31.2 % and was not statistically significant (Q statistic = 13.1, df = 9, p = 0.159). The pooled estimate (-0.004) was significant (z = 3.13, p = 0.002), indicating that the effect of sex became weaker with increasing age. This resulted in near disappearance of the sex difference in the 75+ age group. This finding was also supported by an examination of age- and sex-specific estimates pooled across the surveys. The association of MDE prevalence with sex becomes weaker with age. The interaction may reflect biological effect modification. Investigators should test for, and consider inclusion of age by sex interactions in epidemiological analyses of MDE prevalence.

Age related prevalence of hand osteoarthritis diagnosed by photography (HOASCORE).

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Jonsson, Helgi

2017-12-02

Hand photography has been used in a number of studies to determine the presence and severity of hand osteoarthritis (HOA). The aim of this study was to present age and gender specific prevalences of HOA diagnosed by this method. Six thousand three hundred forty three photographs (from 3676 females and 2667 males aged 40-96) were scored for hand osteoarthritis by a 0-3 grade (0 = no evidence of OA, 1 = possible OA, 2 = definite OA and 3 = severe OA) for each of the three main sites, distal interphalangeal joints (DIP), proximal interphalangeal joints (PIP) and thumb base (CMC1). An aggregate score of 0-9 was thus obtained (HOASCORE) to reflect the severity of HOA in each case. DIP joints were most commonly affected, followed by the thumb base and the PIP joints. Having definite DIP joint OA starts at a younger age compared with the other two sites, and there is a marked female preponderance in the age groups from 55 to 69, but after 70 the gender differences are less marked and the prevalence is fairly stable. PIP joint prevalence also indicates a female preponderance from 60 to 79. Thumb base OA has a more marked female preponderance and a rising prevalence thoughout life. The prevalence of individuals with no evidence of photographic OA (HOASCORE = 0) drops from 88% to 57% between the age categories 40-49 and 50-54 and decreased to 33% in the 70-74 age group with a slower decline after that age. DIP and PIP prevalence were strongly associated with each other with an OR of 16.6(12.8-21.5),p < 0.001 of having definite OA at the other site. This was less marked for the thumb base with an OR of 2.2(1.8-2.7, p < 0.001), and 2.7(2.0-3.5, p < 0.001) of having definite DIP or PIP HOA respectively. The prevalence of hand OA in DIP, PIP and thumb base joints obtained by the photographic HOASCORE method is higher in women and increases after the age of fifty. These results are in line with those obtained by clinical examination and radiography

Flatfoot in school-age children: prevalence and associated factors.

Science.gov (United States)

Sadeghi-Demneh, Ebrahim; Jafarian, Fahimehsadat; Melvin, Jonathan M A; Azadinia, Fatemeh; Shamsi, Fatemeh; Jafarpishe, Mohamad

2015-06-01

Flatfoot has been shown to cause abnormal stresses on the foot and lower extremity. The altered mechanical stresses on these structures can aggravate the foot deformity. Screening of the flatfoot and its associated factors helps detect underlying risks influencing the stresses on the foot. The purpose of this study was to analyze the structure of the medial foot arch and investigate its associated factors in students, aged 7 to 14 years. Multistage cluster sampling was used and each cluster included 2 other random sampling levels. A total of 667 Iranian school children were recruited and their feet were bilaterally evaluated using a static footprint while standing in a fully weightbearing position. The footprint, an observational measurement, and a questionnaire were used for the foot assessment. The prevalence of flatfoot was 17.1% in the population studied. There was no gender difference but the prevalence of flatfoot did decrease with age. The significant differences were observed in the prevalence of flatfoot between normal-weight, overweight, and obese groups (P plantar arch in school-age children is influenced by age and weight. Age and weight were the primary predictive factors of flatfoot. Prognostic, Level IV: Case series. © 2015 The Author(s).

Prevalence of eating disorders in middle-aged women

NARCIS (Netherlands)

Mangweth-Matzek, Barbara; Hoek, Hans W.; Rupp, Claudia I.; Lackner-Seifert, Kerstin; Frey, Nadja; Whitworth, Alexandra B.; Pope, Harrison G.; Kinzl, Johann

Objective: Little is known about the prevalence and correlates of eating disorders (ED) in middle-aged women. Method: We mailed anonymous questionnaires to 1,500 Austrian women aged 40-60 years, assessing ED (defined by DSM-IV), subthreshold ED, body image, and quality of life. We broadly defined

Networks of myelin covariance.

Science.gov (United States)

Melie-Garcia, Lester; Slater, David; Ruef, Anne; Sanabria-Diaz, Gretel; Preisig, Martin; Kherif, Ferath; Draganski, Bogdan; Lutti, Antoine

2018-04-01

Networks of anatomical covariance have been widely used to study connectivity patterns in both normal and pathological brains based on the concurrent changes of morphometric measures (i.e., cortical thickness) between brain structures across subjects (Evans, ). However, the existence of networks of microstructural changes within brain tissue has been largely unexplored so far. In this article, we studied in vivo the concurrent myelination processes among brain anatomical structures that gathered together emerge to form nonrandom networks. We name these "networks of myelin covariance" (Myelin-Nets). The Myelin-Nets were built from quantitative Magnetization Transfer data-an in-vivo magnetic resonance imaging (MRI) marker of myelin content. The synchronicity of the variations in myelin content between anatomical regions was measured by computing the Pearson's correlation coefficient. We were especially interested in elucidating the effect of age on the topological organization of the Myelin-Nets. We therefore selected two age groups: Young-Age (20-31 years old) and Old-Age (60-71 years old) and a pool of participants from 48 to 87 years old for a Myelin-Nets aging trajectory study. We found that the topological organization of the Myelin-Nets is strongly shaped by aging processes. The global myelin correlation strength, between homologous regions and locally in different brain lobes, showed a significant dependence on age. Interestingly, we also showed that the aging process modulates the resilience of the Myelin-Nets to damage of principal network structures. In summary, this work sheds light on the organizational principles driving myelination and myelin degeneration in brain gray matter and how such patterns are modulated by aging. © 2017 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.

Co-variations and clustering of chronic disease behavioral risk factors in China: China Chronic Disease and Risk Factor Surveillance, 2007.

Directory of Open Access Journals (Sweden)

Yichong Li

Full Text Available BACKGROUND: Chronic diseases have become the leading causes of mortality in China and related behavioral risk factors (BRFs changed dramatically in past decades. We aimed to examine the prevalence, co-variations, clustering and the independent correlates of five BRFs at the national level. METHODOLOGY/PRINCIPAL FINDINGS: We used data from the 2007 China Chronic Disease and Risk Factor Surveillance, in which multistage clustering sampling was adopted to collect a nationally representative sample of 49,247 Chinese aged 15 to 69 years. We estimated the prevalence and clustering (mean number of BRFs of five BRFs: tobacco use, excessive alcohol drinking, insufficient intake of vegetable and fruit, physical inactivity, and overweight or obesity. We conducted binary logistic regression models to examine the co-variations among five BRFs with adjustment of demographic and socioeconomic factors, chronic conditions and other BRFs. Ordinal logistic regression was constructed to investigate the independent associations between each covariate and the clustering of BRFs within individuals. Overall, 57.0% of Chinese population had at least two BRFs and the mean number of BRFs is 1.80 (95% confidence interval: 1.78-1.83. Eight of the ten pairs of bivariate associations between the five BRFs were found statistically significant. Chinese with older age, being a male, living in rural areas, having lower education level and lower yearly household income experienced increased likelihood of having more BRFs. CONCLUSIONS/SIGNIFICANCE: Current BRFs place the majority of Chinese aged 15 to 69 years at risk for the future development of chronic disease, which calls for urgent public health programs to reduce these risk factors. Prominent correlations between BRFs imply that a combined package of interventions targeting multiple BRFs might be appropriate. These interventions should target elder population, men, and rural residents, especially those with lower SES.

[Prevalence of anemia in reproductive-age Mexican women].

Science.gov (United States)

Shamah-Levy, Teresa; Villalpando, Salvador; Mundo-Rosas, Verónica; De la Cruz-Góngora, Vanessa; Mejía-Rodríguez, Fabiola; Méndez Gómez-Humarán, Ignacio

2013-01-01

To update the prevalence of anemia and its trend in Mexican women of childbearing age over the past 13 years using information from the National Health and Nutrition Survey 2012 and 2006 (ENSANUT 2012 and ENSANUT 2006, respectively) and from the National Nutrition Survey 1999 (ENN 99). Data came from three national probabilistic surveys, representative at regional and rural / urban level. Hemoglobin (Hb) in women was measured using a HemoCue photometer and classified as anemia according to the WHO criteria. Frequencies and CI95% were estimated for each survey (ENSANUT 2012, ENSANUT 2006 and ENN 99) as well as percentage changes in anemia prevalence among pregnant and non-pregnant women in this survey sequence. The national prevalence of anemia in 2012 in non-pregnant women was 11.6% and in pregnant women was 17.9%. Between 1999 and 2012, a 10 percentage point (pp) decreasing in anemia prevalence was observed in the first ones and a 13.5 pp in the second ones. Although it has declined in the past 13 years, anemia in women of childbearing age remains as a serious public health problem. It is considered necessary to design strategies to prevent iron deficiency and for the early detection of anemia in women.

Prevalence of age-related maculopathy and age-related macular degeneration among the inuit in Greenland. The Greenland Inuit Eye Study

DEFF Research Database (Denmark)

Andersen, Mads Varis Nis; Rosenberg, Thomas; la Cour, Morten

2008-01-01

To examine the age- and gender-specific prevalence and describe the common phenotype of early age-related maculopathy (ARM) and late-stage age-related macular degeneration (AMD) among the Inuit in Greenland.......To examine the age- and gender-specific prevalence and describe the common phenotype of early age-related maculopathy (ARM) and late-stage age-related macular degeneration (AMD) among the Inuit in Greenland....

Age-Specific Prevalence of Visual Impairment and Refractive Error in Children Aged 3-10 Years in Shanghai, China.

Science.gov (United States)

Ma, Yingyan; Qu, Xiaomei; Zhu, Xiaofeng; Xu, Xun; Zhu, Jianfeng; Sankaridurg, Padmaja; Lin, Senlin; Lu, Lina; Zhao, Rong; Wang, Ling; Shi, Huijing; Tan, Hui; You, Xiaofang; Yuan, Hong; Sun, Sifei; Wang, Mingjin; He, Xiangui; Zou, Haidong; Congdon, Nathan

2016-11-01

We assessed changes in age-specific prevalence of refractive error at the time of starting school, by comparing preschool and school age cohorts in Shanghai, China. A cross-sectional study was done in Jiading District, Shanghai during November and December 2013. We randomly selected 7 kindergartens and 7 primary schools, with probability proportionate to size. Chinese children (n = 8398) aged 3 to 10 years were enumerated, and 8267 (98.4%) were included. Children underwent distance visual acuity assessment and refraction measurement by cycloplegic autorefraction and subjective refraction. The prevalence of uncorrected visual acuity (UCVA), presenting visual acuity, and best-corrected visual acuity in the better eye of ≤20/40 was 19.8%, 15.5%, and 1.7%, respectively. Among those with UCVA ≤ 20/40, 93.2% could achieve visual acuity of ≥20/32 with refraction. Only 28.7% (n = 465) of children with UCVA in the better eye of ≤20/40 wore glasses. Prevalence of myopia (spherical equivalent ≤-0.5 diopters [D] in at least one eye) increased from 1.78% in 3-year-olds to 52.2% in 10-year-olds, while prevalence of hyperopia (spherical equivalent ≥+2.0 D) decreased from 17.8% among 3-year-olds to 2.6% by 10 years of age. After adjusting for age, attending elite "high-level" school was statistically associated with greater myopia prevalence. The prevalence of myopia was lower or comparable to that reported in other populations from age 3 to 5 years, but increased dramatically after 6 years, consistent with a strong environmental role of schooling on myopia development.

The Prevalence and Distribution of Aging-Friendly Human Resource Practices.

Science.gov (United States)

Segel-Karpas, Dikla; Bamberger, Peter A; Bacharach, Samuel B

2015-07-01

The aging of the workforce in the developed world has prompted organizations to implement human resource (HR) policies and practices encouraging older workers to defer retirement. However, little is known about the prevalence of such practices, and the organizational factors associated with their adoption. In this study, we used data collected from 2008 to 2009 from a national probability sample of retirement eligible workers in the United States (N = 407) to assess the prevalence of aging-friendly human resource practices (AFHRP), and their organizational predictors. Results indicate that employee wellness programs, unpaid leave, and reassignment based on physical needs are among the most prevalent AFHRP. However, in the vast majority of enterprises, AFHRP are limited. Results also indicate that projected organizational growth and a focus on internal labor market practices are positively associated with the adoption of AFHRP. Organizational size and the degree of unionization, while positively associated with aging-friendly benefits, were inversely associated with flexibility practices. © The Author(s) 2015.

Progress on Nuclear Data Covariances: AFCI-1.2 Covariance Library

International Nuclear Information System (INIS)

Oblozinsky, P.; Oblozinsky, P.; Mattoon, C.M.; Herman, M.; Mughabghab, S.F.; Pigni, M.T.; Talou, P.; Hale, G.M.; Kahler, A.C.; Kawano, T.; Little, R.C.; Young, P.G

2009-01-01

Improved neutron cross section covariances were produced for 110 materials including 12 light nuclei (coolants and moderators), 78 structural materials and fission products, and 20 actinides. Improved covariances were organized into AFCI-1.2 covariance library in 33-energy groups, from 10 -5 eV to 19.6 MeV. BNL contributed improved covariance data for the following materials: 23 Na and 55 Mn where more detailed evaluation was done; improvements in major structural materials 52 Cr, 56 Fe and 58 Ni; improved estimates for remaining structural materials and fission products; improved covariances for 14 minor actinides, and estimates of mubar covariances for 23 Na and 56 Fe. LANL contributed improved covariance data for 235 U and 239 Pu including prompt neutron fission spectra and completely new evaluation for 240 Pu. New R-matrix evaluation for 16 O including mubar covariances is under completion. BNL assembled the library and performed basic testing using improved procedures including inspection of uncertainty and correlation plots for each material. The AFCI-1.2 library was released to ANL and INL in August 2009.

Trends in new injuries, prevalent cases, and aging with spinal cord injury.

Science.gov (United States)

DeVivo, Michael J; Chen, Yuying

2011-03-01

To determine the characteristics of the newly injured and prevalent population with spinal cord injury (SCI) and assess trends over time. Prospective cohort study. SCI Model Systems and Shriners Hospital SCI units. The study population included people whose injuries occurred from 1935 to 2008 (N=45,442). The prevalent population was estimated based on those who were still alive in 2008. Losses to follow-up (approximately 10%) were excluded from the prevalent population. Not applicable. Demographic and injury characteristics, mortality, self-reported health, rehospitalization, FIM, Craig Handicap Assessment and Reporting Technique, and the Diener Satisfaction with Life Scale. Mean age at injury increased 9 years since the 1970s. Injuries caused by falls and injuries resulting in high-level tetraplegia and ventilator dependency are increasing, while neurologically complete injuries are decreasing. Discharge to a nursing home is increasing. The mean age of the prevalent population is slightly higher than that of newly injured individuals, and the percentage of incident and prevalent cases older than 60 years is the same (13%). Prevalent cases tend to be less severely injured than incident cases, and less than 5% of prevalent cases reside in nursing homes. Within the prevalent population, life satisfaction and community participation are greater among persons who are at least 30 years postinjury. These findings are a result of very high mortality rates observed after 60 years of age. Within the prevalent population, the percentage of elderly persons will not increase meaningfully. Those who reach older ages will typically have incomplete and/or lower-level injuries and will have relatively high degrees of independence and overall good health. Copyright © 2011 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Smoking Prevalance in Women Aged Over 15 in Mardin City Center

Directory of Open Access Journals (Sweden)

Gunay Saka

2008-04-01

Full Text Available AIM/BACKGROUND: The purpose of this study is to determine prevalence of smoking and factors associated with it, in women aged over 15 years in Mardin city center. METHODS: This was a cross sectional study. The study population were 21 890 women aged over 15 years living in the area of five primary health centers (PHC in city center of Mardin. Minimum sample size was calculated 759 by using Epi Info2000. Health school students interviewed with women face to face by using questionnaire in April –May 2005. We randomly selected 12 streets from each PCH. From each street first 25 woman were included to the study. Because of data failure, 29 women’s questionnaires excluded and totally 1471 women composed the main source of our study data. Data were recorded and analysed by computer. Percentage and khi square test were used for statistical analyses. RESULTS: Smoking prevalence rate and giving up smoking rates were 22,9% and 3.9% respectively. Smoking prevalence was the highest in 25-34 age group (31.8% and the lowest in 55 years and over age group (10% (p<0.01. In terms of education the highest prevalence of smoking was among university graduates (34.3% while the lowest prevalence was among non-educated group (16.0% (p<0.01. Smoking prevalence was 30.4% in divorced women, 24.4% in married and 22.4 in unmarried group (p<0.05. Prevalence of smoking in working women (40.2% was higher than in non working group (21.7% (p<0.01. CONCLUSION: Smoking prevalence was high in women in Mardin and it was significant public health concern. The risky groups were young, higher educated, divorced and working woman. Detailed research must plan in these groups. Smoking cessation programs should target the population subgroups of women at highest risk of smoking. [TAF Prev Med Bull 2008; 7(2.000: 141-146

Smoking Prevalance in Women Aged Over 15 in Mardin City Center

Directory of Open Access Journals (Sweden)

Vasfiye Deger

2008-04-01

Full Text Available AIM/BACKGROUND: The purpose of this study is to determine prevalence of smoking and factors associated with it, in women aged over 15 years in Mardin city center. METHODS: This was a cross sectional study. The study population were 21 890 women aged over 15 years living in the area of five primary health centers (PHC in city center of Mardin. Minimum sample size was calculated 759 by using Epi Info2000. Health school students interviewed with women face to face by using questionnaire in April –May 2005. We randomly selected 12 streets from each PCH. From each street first 25 woman were included to the study. Because of data failure, 29 women’s questionnaires excluded and totally 1471 women composed the main source of our study data. Data were recorded and analysed by computer. Percentage and khi square test were used for statistical analyses. RESULTS: Smoking prevalence rate and giving up smoking rates were 22,9% and 3.9% respectively. Smoking prevalence was the highest in 25-34 age group (31.8% and the lowest in 55 years and over age group (10% (p<0.01. In terms of education the highest prevalence of smoking was among university graduates (34.3% while the lowest prevalence was among non-educated group (16.0% (p<0.01. Smoking prevalence was 30.4% in divorced women, 24.4% in married and 22.4 in unmarried group (p<0.05. Prevalence of smoking in working women (40.2% was higher than in non working group (21.7% (p<0.01. CONCLUSION: Smoking prevalence was high in women in Mardin and it was significant public health concern. The risky groups were young, higher educated, divorced and working woman. Detailed research must plan in these groups. Smoking cessation programs should target the population subgroups of women at highest risk of smoking. [TAF Prev Med Bull. 2008; 7(2: 141-146

Anxiety Disorders in Old Age: Psychiatric Comorbidities, Quality of Life, and Prevalence According to Age, Gender, and Country.

Science.gov (United States)

Canuto, Alessandra; Weber, Kerstin; Baertschi, Marc; Andreas, Sylke; Volkert, Jana; Dehoust, Maria Christina; Sehner, Susanne; Suling, Anna; Wegscheider, Karl; Ausín, Berta; Crawford, Mike J; Da Ronch, Chiara; Grassi, Luigi; Hershkovitz, Yael; Muñoz, Manuel; Quirk, Alan; Rotenstein, Ora; Santos-Olmo, Ana Belén; Shalev, Arieh; Strehle, Jens; Wittchen, Hans-Ulrich; Schulz, Holger; Härter, Martin

2018-02-01

Previous estimates of the prevalence of anxiety disorders in late life vary greatly due to the lack of reliable diagnostic tools. This MentDis_ICF65+ study assessed 12-month prevalence rates of anxiety disorders and age- and gender-related differences in comorbidities, as well as impact on quality of life. The study used a cross-sectional multicenter survey. The study sample comprised 3,142 men and women aged 65 to 84 years, living in five European countries and Israel. Anxiety disorders were assessed using computer-assisted face-to-face interviews with an age-appropriate diagnostic interview (CIDI65+). The prevalence of anxiety disorders was 17.2%. Agoraphobia was the most frequent disorder (4.9%), followed by panic disorder (3.8%), animal phobia (3.5%), general anxiety disorder (3.1%), post-traumatic stress disorder (1.4%), social phobia (1.3%), and obsessive-compulsive disorder (0.8%). The prevalence rate of any anxiety disorder dropped by 40% to 47% in adults aged 75-84 years compared with those aged 65-74 years. Women were twice as likely to present with agoraphobia or general anxiety disorder as men. Only panic disorder and phobia were associated with comorbid major depression. The negative relationship with quality of life was limited to agoraphobia and generalized anxiety disorder. The age-appropriate CIDI65+ led to higher prevalence rates of anxiety disorders in the elderly, yet to weaker associations with comorbidities and impaired quality of life compared with previous studies. Copyright © 2017 American Association for Geriatric Psychiatry. Published by Elsevier Inc. All rights reserved.

Prevalence of Age-Related Macular Degeneration in Europe: The Past and the Future.

Science.gov (United States)

Colijn, Johanna M; Buitendijk, Gabriëlle H S; Prokofyeva, Elena; Alves, Dalila; Cachulo, Maria L; Khawaja, Anthony P; Cougnard-Gregoire, Audrey; Merle, Bénédicte M J; Korb, Christina; Erke, Maja G; Bron, Alain; Anastasopoulos, Eleftherios; Meester-Smoor, Magda A; Segato, Tatiana; Piermarocchi, Stefano; de Jong, Paulus T V M; Vingerling, Johannes R; Topouzis, Fotis; Creuzot-Garcher, Catherine; Bertelsen, Geir; Pfeiffer, Norbert; Fletcher, Astrid E; Foster, Paul J; Silva, Rufino; Korobelnik, Jean-François; Delcourt, Cécile; Klaver, Caroline C W

2017-12-01

Age-related macular degeneration (AMD) is a frequent, complex disorder in elderly of European ancestry. Risk profiles and treatment options have changed considerably over the years, which may have affected disease prevalence and outcome. We determined the prevalence of early and late AMD in Europe from 1990 to 2013 using the European Eye Epidemiology (E3) consortium, and made projections for the future. Meta-analysis of prevalence data. A total of 42 080 individuals 40 years of age and older participating in 14 population-based cohorts from 10 countries in Europe. AMD was diagnosed based on fundus photographs using the Rotterdam Classification. Prevalence of early and late AMD was calculated using random-effects meta-analysis stratified for age, birth cohort, gender, geographic region, and time period of the study. Best-corrected visual acuity (BCVA) was compared between late AMD subtypes; geographic atrophy (GA) and choroidal neovascularization (CNV). Prevalence of early and late AMD, BCVA, and number of AMD cases. Prevalence of early AMD increased from 3.5% (95% confidence interval [CI] 2.1%-5.0%) in those aged 55-59 years to 17.6% (95% CI 13.6%-21.5%) in those aged ≥85 years; for late AMD these figures were 0.1% (95% CI 0.04%-0.3%) and 9.8% (95% CI 6.3%-13.3%), respectively. We observed a decreasing prevalence of late AMD after 2006, which became most prominent after age 70. Prevalences were similar for gender across all age groups except for late AMD in the oldest age category, and a trend was found showing a higher prevalence of CNV in Northern Europe. After 2006, fewer eyes and fewer ≥80-year-old subjects with CNV were visually impaired (P = 0.016). Projections of AMD showed an almost doubling of affected persons despite a decreasing prevalence. By 2040, the number of individuals in Europe with early AMD will range between 14.9 and 21.5 million, and for late AMD between 3.9 and 4.8 million. We observed a decreasing prevalence of AMD and an improvement

The prevalence of metabolic syndrome among older adults in Ecuador: Results of the SABE survey.

Science.gov (United States)

Orces, Carlos H; Gavilanez, Enrique Lopez

2017-12-01

To describe the prevalence of metabolic syndrome among older adults in Ecuador. A secondary objective was to examine the relationship between metabolic syndrome and its components and insulin resistance among non-diabetic participants. The National Survey of Health, Wellbeing, and Aging survey was used to examine the prevalence of metabolic syndrome according to demographic, behavioral, and health characteristics of the participants. Logistic regression models adjusted for covariates were used to examine the independent association of metabolic syndrome and its components and insulin resistance in non-diabetic older adults. Of 2298 participants with a mean age of 71.6 (SD 8.1) years, the prevalence of metabolic syndrome was 66.0% (95% CI, 62.6%, 69.3%) in women and 47.1% (95% CI, 43.2%, 50.9) in men. However, even higher prevalence rates were seen among literate individuals, residents from urban areas of the coastal and Andes Mountains region, obese subjects, those diagnosed with diabetes, and participants with≥2 comorbidities. Overall, abdominal obesity followed by elevated blood pressure were the metabolic syndrome components more prevalent and associated with insulin resistance among older Ecuadorians. Moreover, after adjustment for covariates, older adults defined as having metabolic syndrome had a 3-fold higher odds of having insulin resistance as compared with those without. The prevalence of metabolic syndrome is high among older adults in Ecuador. The present findings may assist public health authorities to implement programs of lifestyle and behavioral modification targeting older adults at increased risk for this cardio metabolic disorder. Copyright © 2017 Diabetes India. Published by Elsevier Ltd. All rights reserved.

The causes of variation in the presence of genetic covariance between sexual traits and preferences.

Science.gov (United States)

Fowler-Finn, Kasey D; Rodríguez, Rafael L

2016-05-01

Mating traits and mate preferences often show patterns of tight correspondence across populations and species. These patterns of apparent coevolution may result from a genetic association between traits and preferences (i.e. trait-preference genetic covariance). We review the literature on trait-preference covariance to determine its prevalence and potential biological relevance. Of the 43 studies we identified, a surprising 63% detected covariance. We test multiple hypotheses for factors that may influence the likelihood of detecting this covariance. The main predictor was the presence of genetic variation in mate preferences, which is one of the three main conditions required for the establishment of covariance. In fact, 89% of the nine studies where heritability of preference was high detected covariance. Variables pertaining to the experimental methods and type of traits involved in different studies did not greatly influence the detection of trait-preference covariance. Trait-preference genetic covariance appears to be widespread and therefore represents an important and currently underappreciated factor in the coevolution of traits and preferences. © 2015 Cambridge Philosophical Society.

Prevalence of Food Addiction Among Low-Income Reproductive-Aged Women.

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Berenson, Abbey B; Laz, Tabassum H; Pohlmeier, Ali M; Rahman, Mahbubur; Cunningham, Kathryn A

2015-09-01

Hyperpalatable foods (i.e., high in salt, sugar, or fat) have been shown to have addictive properties that may contribute to overeating. Prior studies conducted on food addiction behaviors are mostly based on white and middle-aged women. Data are not available, however, on reproductive-aged women from other races/ethnicities or low-income women. The purpose of this study was to examine the prevalence and correlates of food addiction among multiethnic women of low socioeconomic status. We conducted a cross-sectional survey of health behaviors, including food addiction according to the Yale Food Addiction Scale (YFAS) between July 2010 and February 2011 among 18- to 40-year-old low-income women attending reproductive-health clinics (N = 1,067). Overall, 2.8% of women surveyed met the diagnosis of food addiction. The prevalence of food addiction did not differ by age group, race/ethnicity, education, income, or body mass index categories, tobacco and alcohol use, or physical activity. However, it did differ by level of depression (p addiction among low-income, reproductive-aged women. Racial differences were observed in the YFAS symptom count score, but not in the overall prevalence of food addition. Additionally, women with food addiction had higher levels of depression than women without food addiction.

Age at onset of substance abuse: a crucial covariate of psychopathic traits and aggression in adult offenders.

Science.gov (United States)

Gustavson, Christina; Ståhlberg, Ola; Sjödin, Anna-Kari; Forsman, Anders; Nilsson, Thomas; Anckarsäter, Henrik

2007-10-31

To examine age at onset of substance abuse in relation to other factors of relevance to criminal behavior, we compared Life History of Aggression (LHA) scores, traits of psychopathy according to the Psychopathy Checklist--Revised (PCL-R), and violent recidivism in 100 violent offenders with early (before the age of 18) versus late onset of abuse or dependence. Of 56 subjects with a history of alcohol and/or drug abuse, an early onset was ascertained in 31. The duration of abuse did not correlate with the LHA and PCL-R scores or with violent recidivism, but the age at onset correlated strongly with all these factors and also remained their strongest correlate in multivariate models including childhood-onset attention deficit/hyperactivity disorder, conduct disorder, and drug abuse as covariates. Strong mathematical associations with aggression, psychopathy, and recidivism pointed to age at onset of substance abuse as a marker of possible complications that require preventive social, educational and medical measures.

Age-specific prevalence of cervical human papillomavirus infection ...

African Journals Online (AJOL)

This cross-sectional study describes the age-specific prevalence of human papillomavirus (HPV) infection and cytological abnormalities among this urban and peri-urban population. Method. Over the period March 2009 - September 2011, 1 524 women attending public sector primary healthcare clinics were invited to

Structural and Maturational Covariance in Early Childhood Brain Development.

Science.gov (United States)

Geng, Xiujuan; Li, Gang; Lu, Zhaohua; Gao, Wei; Wang, Li; Shen, Dinggang; Zhu, Hongtu; Gilmore, John H

2017-03-01

Brain structural covariance networks (SCNs) composed of regions with correlated variation are altered in neuropsychiatric disease and change with age. Little is known about the development of SCNs in early childhood, a period of rapid cortical growth. We investigated the development of structural and maturational covariance networks, including default, dorsal attention, primary visual and sensorimotor networks in a longitudinal population of 118 children after birth to 2 years old and compared them with intrinsic functional connectivity networks. We found that structural covariance of all networks exhibit strong correlations mostly limited to their seed regions. By Age 2, default and dorsal attention structural networks are much less distributed compared with their functional maps. The maturational covariance maps, however, revealed significant couplings in rates of change between distributed regions, which partially recapitulate their functional networks. The structural and maturational covariance of the primary visual and sensorimotor networks shows similar patterns to the corresponding functional networks. Results indicate that functional networks are in place prior to structural networks, that correlated structural patterns in adult may arise in part from coordinated cortical maturation, and that regional co-activation in functional networks may guide and refine the maturation of SCNs over childhood development. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Higher Prevalence of Left-Handedness in Twins? Not After Controlling Birth Time Confounders.

Science.gov (United States)

Heikkilä, Kauko; Vuoksimaa, Eero; Saari-Kemppainen, Aulikki; Kaprio, Jaakko; Rose, Richard J; Haukka, Jari; Pitkäniemi, Janne; Iivanainen, Matti

2015-10-01

Pregnancy- and birth-related factors may have an effect on handedness. Compared with singletons, twins have a lower birth weight, shorter gestational age, and are at higher risk for birth complications. We tested whether the prevalence of left-handedness is higher among twins than singletons, and if so, whether that difference is fully explained by pregnancy and birth-related differences between twins and singletons. We analyzed Finnish population-based datasets; included were 8,786 twins and 5,892 singletons with information on birth weight (n = 12,381), Apgar scores (n = 11,129), and gestational age (n = 11,811). Two twin cohorts were involved: FinnTwin12 included twins born during 1983-1987, and FinnTwin16 included twins born during 1974-1979. We had two comparison groups of singletons: 4,101 individuals born during 1986-1988 and enrolled in the Helsinki Ultrasound Trial, and 1,791 individuals who were partners of FinnTwin16 twins. We used logistic regression models with writing hand as the outcome for comparison and evaluating effects of covariates. Left-handedness was more common in twins (9.67%) than in singletons (8.27%; p = .004). However, Apgar scores were associated with handedness, and after controlling for covariates, we found no difference in the prevalence of left-handedness between twins and singletons. Increased left-handedness among twins, often reported by others, was evident in our data, but only among our older twin cohorts, and that association disappeared after removing effects of perinatal covariates.

Association between the prevalence of depression and age in a large representative German sample of people aged 53 to 80 years.

Science.gov (United States)

Wild, Beate; Herzog, Wolfgang; Schellberg, Dieter; Lechner, Sabine; Niehoff, Doro; Brenner, Hermann; Rothenbacher, Dietrich; Stegmaier, Christa; Raum, Elke

2012-04-01

The aim of the study was to determine the association between the prevalence of clinically significant depression and age in a large representative sample of elderly German people. In the second follow-up (2005-2007) of the ESTHER cohort study, the 15-item geriatric depression scale (GDS-15) as well as a sociodemographic and clinical questionnaire were administered to a representative sample of 8270 people of ages 53 to 80 years. The prevalence of clinically significant depression was estimated using a GDS cut-off score of 5/6. Prevalence rates were estimated for the different age categories. Association between depression and age was analyzed using logistic regression, adjusted for gender, co-morbid medical disorders, education, marital status, physical activity, smoking, self-perceived cognitive impairment, and anti-depressive medication. Of the participants, 7878 (95.3%) completed more than twelve GDS items and were included in the study. The prevalence of clinically significant depression was 16.0% (95%CI = [15.2; 16.6]). The function of depression prevalence dependent on age group showed a U-shaped pattern (53-59: 21.0%, CI = [18.9; 23.3]; 60-64: 17.7%, CI = [15.7; 19.7]; 65-69: 12.6%, CI = [11.2; 14.0]; 70-74: 14.4%, CI = [12.6; 16.0]; 75-80: 17.1%, CI = [14.9; 19.4]). Adjusted odds ratios showed that the chances of being depressive decrease with the age category but remain relatively stable for people aged 65 and over. The prevalence of depression in the elderly seems to be associated with the age category. Adjusted odds ratios showed that people aged 60 and older had lower chances of being depressive than people aged 53 to 59 years. Copyright © 2011 John Wiley & Sons, Ltd.

Association between adolescent idiopathic scoliosis prevalence and age at menarche in different geographic latitudes

Directory of Open Access Journals (Sweden)

Mihas Constantinos

2006-05-01

Full Text Available Abstract Background Age at menarche is considered a reliable prognostic factor for idiopathic scoliosis and varies in different geographic latitudes. Adolescent idiopathic scoliosis prevalence has also been reported to be different in various latitudes and demonstrates higher values in northern countries. A study on epidemiological reports from the literature was conducted to investigate a possible association between prevalence of adolescent idiopathic scoliosis and age at menarche among normal girls in various geographic latitudes. An attempt is also made to implicate a possible role of melatonin in the above association. Material-methods 20 peer-reviewed published papers reporting adolescent idiopathic scoliosis prevalence and 33 peer-reviewed papers reporting age at menarche in normal girls from most geographic areas of the northern hemisphere were retrieved from the literature. The geographic latitude of each centre where a particular study was originated was documented. The statistical analysis included regression of the adolescent idiopathic scoliosis prevalence and age at menarche by latitude. Results The regression of prevalence of adolescent idiopathic scoliosis and age at menarche by latitude is statistically significant (p Conclusion Late age at menarche is parallel with higher prevalence of adolescent idiopathic scoliosis. Pubarche appears later in girls that live in northern latitudes and thus prolongs the period of spine vulnerability while other pre-existing or aetiological factors are contributing to the development of adolescent idiopathic scoliosis. A possible role of geography in the pathogenesis of idiopathic scoliosis is discussed, as it appears that latitude which differentiates the sunlight influences melatonin secretion and modifies age at menarche, which is associated to the prevalence of idiopathic scoliosis.

Contributions to Large Covariance and Inverse Covariance Matrices Estimation

OpenAIRE

Kang, Xiaoning

2016-01-01

Estimation of covariance matrix and its inverse is of great importance in multivariate statistics with broad applications such as dimension reduction, portfolio optimization, linear discriminant analysis and gene expression analysis. However, accurate estimation of covariance or inverse covariance matrices is challenging due to the positive definiteness constraint and large number of parameters, especially in the high-dimensional cases. In this thesis, I develop several approaches for estimat...

Prevalence of Unique Pediatric Pathologies Encountered by Paramedic Students Across Age Groups.

Science.gov (United States)

Ernest, Eric V; Brazelton, Tom B; Carhart, Elliot D; Studnek, Jonathan R; Tritt, Patricia L; Philip, Genghis A; Burnett, Aaron M

2016-08-01

Introduction Traditionally, Emergency Medical Services (EMS) educators have divided the pediatric population into age groups to assist in targeting their clinical and didactic curriculum. Currently, the accrediting body for paramedic training programs requires student exposure to pediatric patients based entirely on age without specifying exposure to specific pathologies within each age stratification. Identifying which pathologies are most common within the different pediatric age groups would allow educators to design curriculum targeting the most prevalent pathologies in each age group and incorporating the physiologic and psychological developmental milestones commonly seen at that age. Hypothesis It was hypothesized that there are unique clusterings of pathologies, represented by paramedic student primary impressions, that are found in different age groups which can be used to target provider education. This is a retrospective review of prospectively collected data documented by paramedic students in the Fisdap (Field Internship Student Data Acquisition Project; Saint Paul, Minnesota USA) database over a one-year period. For the purposes of this study, pediatric patients were defined arbitrarily as those between the ages of 0-16 years. All paramedic student primary impressions recorded in Fisdap for patients aged 0-16 years were abstracted. Primary impression by age was calculated and graphed. The frequency of primary impression was then assessed for significance of trend by age with an alpha ≤.05 considered significant. The following primary impressions showed clinically and statistically significant variability in prevalence among different pediatric age groups: respiratory distress, medical-other, abdominal pain, seizure, overdose/poisoning, behavioral, and cardiac. In patients less than 13 years old, respiratory and other-medical were the most common two primary impressions and both decreased with age. In patients 5-16 years old, the prevalence of

Covariant Transform

OpenAIRE

Kisil, Vladimir V.

2010-01-01

The paper develops theory of covariant transform, which is inspired by the wavelet construction. It was observed that many interesting types of wavelets (or coherent states) arise from group representations which are not square integrable or vacuum vectors which are not admissible. Covariant transform extends an applicability of the popular wavelets construction to classic examples like the Hardy space H_2, Banach spaces, covariant functional calculus and many others. Keywords: Wavelets, cohe...

Oral acetylsalicylic acid and prevalence of actinic keratosis.

Science.gov (United States)

Schmitt, Juliano; Miot, Hélio

2014-01-01

To investigate the influence of a regular oral use of acetylsalicylic acid in the prevalence of actinic keratosis. A case-control study with dermatologic outpatients above 50 years of age assessed between 2009 and 2011. Cases were defined as those who had been under regular use of oral acetylsalicylic acid for more than six consecutive months. The assessment focused on: age, sex, skin-type, tobacco smoking, use of medication, occurrence of individual or family skin cancer, and sunscreen and sun exposure habits. Actinic keratoses were counted in the medial region of the face and upper limbs. Counts were adjusted by co-variables based on a generalized linear model. A total of 74 cases and 216 controls were assessed. The median time of acetylsalicylic acid use was 36 months. Cases differed from controls as to the highest age, highest prevalence of use of angiotensin-converting enzyme inhibitors and fewer keratosis on the face and on the upper limbs (pkeratosis and upper-limb erythematous actinic keratosis (pkeratosis, especially facial and erythematous ones.

Are your covariates under control? How normalization can re-introduce covariate effects.

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Pain, Oliver; Dudbridge, Frank; Ronald, Angelica

2018-04-30

Many statistical tests rely on the assumption that the residuals of a model are normally distributed. Rank-based inverse normal transformation (INT) of the dependent variable is one of the most popular approaches to satisfy the normality assumption. When covariates are included in the analysis, a common approach is to first adjust for the covariates and then normalize the residuals. This study investigated the effect of regressing covariates against the dependent variable and then applying rank-based INT to the residuals. The correlation between the dependent variable and covariates at each stage of processing was assessed. An alternative approach was tested in which rank-based INT was applied to the dependent variable before regressing covariates. Analyses based on both simulated and real data examples demonstrated that applying rank-based INT to the dependent variable residuals after regressing out covariates re-introduces a linear correlation between the dependent variable and covariates, increasing type-I errors and reducing power. On the other hand, when rank-based INT was applied prior to controlling for covariate effects, residuals were normally distributed and linearly uncorrelated with covariates. This latter approach is therefore recommended in situations were normality of the dependent variable is required.

Linear Regression with a Randomly Censored Covariate: Application to an Alzheimer's Study.

Science.gov (United States)

Atem, Folefac D; Qian, Jing; Maye, Jacqueline E; Johnson, Keith A; Betensky, Rebecca A

2017-01-01

The association between maternal age of onset of dementia and amyloid deposition (measured by in vivo positron emission tomography (PET) imaging) in cognitively normal older offspring is of interest. In a regression model for amyloid, special methods are required due to the random right censoring of the covariate of maternal age of onset of dementia. Prior literature has proposed methods to address the problem of censoring due to assay limit of detection, but not random censoring. We propose imputation methods and a survival regression method that do not require parametric assumptions about the distribution of the censored covariate. Existing imputation methods address missing covariates, but not right censored covariates. In simulation studies, we compare these methods to the simple, but inefficient complete case analysis, and to thresholding approaches. We apply the methods to the Alzheimer's study.

Prevalence of vaginitis in different age groups among females in Greece.

Science.gov (United States)

Sianou, Argiri; Galyfos, George; Moragianni, Dimitra; Baka, Stavroula

2017-08-01

Patients with vaginitis were classified into four groups: Group A (prepubertal under-aged females); Group B (pubertal under-aged females); Group C (reproductive age adult females); Group D (postmenopausal adult females). All vaginal specimens underwent microscopy, amine testing, Gram staining and culturing. Overall, 163 patients were included (33, 14, 81 and 35 patients, respectively). The most common infection was bacterial vaginosis (BV), followed by Ureaplasma infection, aerobic vaginitis (AV) and candidiasis. The most common AV-associated organism was Escherichia coli and the most common BV-associated organism was Gardnerella vaginalis. AV was more frequent in Group A, BV in Group C and Ureaplasma infections in Groups C/D. Decreased lactobacilli concentrations were associated with BV in fertile patients (Groups B-C). Although presentation of vaginitis is similar among females of different age in Greece, type and prevalence of pathogens differ. Normal vaginal flora changes are associated with higher risk of vaginitis in specific age groups. Impact Statement The worldwide incidence of reproductive tract infections has been increasing, with specific pathogens being associated with significant risk of morbidity and complications. However, literature data on the distribution of such infections in different age groups is limited. Therefore, the aim of this study was to provide data on the prevalence and causes of vaginitis in adult and non-adult females of all ages. This study has shown that although presentation of vaginitis is similar among females of different age groups and menstrual status in Greece, type and prevalence of responsible pathogens are different among groups. Changes in normal vaginal flora seem to be associated with higher risk of vaginitis in specific age-groups as well. These findings could contribute in adjusting diagnostic and therapeutic strategies for each age group according to the prevailing pathogens. Further research on antibiotic

Prevalence of and risk factors for age-related macular degeneration in a multiethnic Asian cohort.

Science.gov (United States)

Cheung, Chui Ming Gemmy; Tai, E Shyong; Kawasaki, Ryo; Tay, Wan Ting; Lee, Jeannette L; Hamzah, Haslina; Wong, Tien Y

2012-04-01

To describe the prevalence of and risk factors for age-related macular degeneration (AMD) in a multiethnic Asian cohort of Chinese, Malay, and Indian persons. In this population-based study, 3172 persons of Chinese, Malay, and Indian ethnicities 40 years and older were included. Participants underwent comprehensive systemic and ocular examination, retinal photography, and laboratory investigations. Early and late AMD signs were graded from retinal photographs. Age-standardized prevalence estimates were calculated using the 2010 Singapore adult population as the standard population. Association with a range of systemic risk factors was analyzed. Of 3172 participants, AMD was present in 211 subjects. Age-standardized prevalence of AMD was 7.0% in persons 40 years and older. The age-standardized prevalence was similar in all 3 Asian ethnic groups: Chinese, 7.3%; Malay, 7.7%; and Indian, 5.7% (P value = .44). The prevalence increased with age and was higher in men. Of the range of risk factors evaluated, only myopic refractive error (Chinese men. The prevalence of AMD was similar in the 3 major ethnic groups in Asia and comparable with white populations. Myopic refractive error was associated with reduced risk of AMD in Chinese men.

Covariance evaluation system

International Nuclear Information System (INIS)

Kawano, Toshihiko; Shibata, Keiichi.

1997-09-01

A covariance evaluation system for the evaluated nuclear data library was established. The parameter estimation method and the least squares method with a spline function are used to generate the covariance data. Uncertainties of nuclear reaction model parameters are estimated from experimental data uncertainties, then the covariance of the evaluated cross sections is calculated by means of error propagation. Computer programs ELIESE-3, EGNASH4, ECIS, and CASTHY are used. Covariances of 238 U reaction cross sections were calculated with this system. (author)

An age structured model for obesity prevalence dynamics in populations

Directory of Open Access Journals (Sweden)

Gilberto González Parra

2010-08-01

Full Text Available Objective. Modeling the correlation of the development of obesity in a population with age and time and predict the dynamics of the correlation of the development of obesity in a population with age and time under different scenarios in Valencia (Spain. Materials and methods. An age structured mathematical model is used to describe the future dynamics of obesity prevalence for different ages in human population with excess weight. Simulation of the model with parameters estimated using the Health Survey of the Region of Valencia 2000 (4.319 interviews and Health Survey of the Region of Valencia 2005 (4.012 interviews. The model considers only overweight and obese populations since these subpopulations are the most relevant on obesity health concern. Results. The model allows predicting and studying the prevalence of obesity for each age. Results showed an increasing trend of obesity in the following years in well accordance with the trend observed in several countries. Conclusions. Based on the numerical simulations it is possible to conclude that the age structured mathematical model is suitable to forecast the obesity epidemic in each age group in different countries. Additionally, this type of models may be applied to study other characteristics of other populations such animal populations.

The prevalence of lacunar infarct decreases with aging in the elderly: a case-controlled analysis

Directory of Open Access Journals (Sweden)

Cai Z

2016-05-01

Full Text Available Zhiyou Cai,1 Wenbo He,1 Chuan-yong Peng,2 Jin Zhou,2 Qi-lan Xu,2 Zong-shan Wu2 1Department of Neurology, Renmin Hospital, Hubei University of Medicine, Shiyan Renmin Hospital, Shiyan, Hubei Province, 2The Examination Center of Magnetic Resonance Imaging, the Lu’an Affiliated Hospital of Anhui Medical University, Lu’an People’s Hospital, Lu’an, Anhui Province, People’s Republic of China Background and purpose: Lacunar infarct (LI is well known as a heterogeneous primary disorder of cerebral small vessel. Compelling results have demonstrated that age is a risk factor to the prevalence of LI. However, the relationship between age and the prevalence of LI remains obscure. It is essential to note the relationship between age and the prevalence of LI through more clinical data. Methods: A total of 3,500 patients were included in the case-controlled study. All data were collected from the Examination Center of Magnetic Resonance Imaging, Lu’an People’s Hospital from January 2014 to December 2015. A primary discharge diagnosis of LI was done, and all subjects were evaluated as retrospective data. The relationship between the risk factors and the prevalence of diabetes and the relationship between age and the prevalence of diabetes was analyzed. A chi-square test was used to analyze the associations between different variables. A one-way analysis of variance was used to test the equality of three or more means at one time by using variances. Statistical significance was defined as a P-value of <0.05. Results: The one-way analysis of variance demonstrated that the prevalence of LI increased with age before 60 years and decreased with age after 69 years. The same results were found in both the male and the female subjects. These results showed that the age-related risk factors (hypertension, diabetes, cerebral infarct, cardiovascular diseases, smoking, and drinking have no relationship with the prevalence of LI on the basis of age. There is

Refining estimates of prescription durations by using observed covariates in pharmacoepidemiological databases

DEFF Research Database (Denmark)

Støvring, Henrik; Pottegård, Anton; Hallas, Jesper

2017-01-01

, patient sex and patient age as covariates. Results: The estimated prescription durations increased with redeemed amount and age. Women generally had longer prescription durations, which increased more with age than men. For 70-year-old women redeeming 300+ pills, we predicted a 95th percentile...... of the inter-arrival density of 225 (95%CI: 201, 249) days. For 50-year-old men redeeming 100 pills, the corresponding prediction was 97 (88, 106) days. Conclusions: The algorithm allows estimation of prescription durations based on the reverse WTD, which can depend upon observed covariates. Statistical...

Lactose maldigestion - age-specific prevalence black and Indian ...

African Journals Online (AJOL)

A study was performed to determine the prevalence and age of onset of primary lactose maldigestion in healthy black and Indian children, and to determine whether this was of clinical significance. More black (22 of 44 - 50%) than Indian children (10 of 45 - 22,2%) had lactose maldigestion (P < 0,02), the development of ...

On the algebraic structure of covariant anomalies and covariant Schwinger terms

International Nuclear Information System (INIS)

Kelnhofer, G.

1992-01-01

A cohomological characterization of covariant anomalies and covariant Schwinger terms in an anomalous Yang-Mills theory is formulated and w ill be geometrically interpreted. The BRS and anti-BRS transformations are defined as purely differential geometric objects. Finally the covariant descent equations are formulated within this context. (author)

A class of covariate-dependent spatiotemporal covariance functions

Science.gov (United States)

Reich, Brian J; Eidsvik, Jo; Guindani, Michele; Nail, Amy J; Schmidt, Alexandra M.

2014-01-01

In geostatistics, it is common to model spatially distributed phenomena through an underlying stationary and isotropic spatial process. However, these assumptions are often untenable in practice because of the influence of local effects in the correlation structure. Therefore, it has been of prolonged interest in the literature to provide flexible and effective ways to model non-stationarity in the spatial effects. Arguably, due to the local nature of the problem, we might envision that the correlation structure would be highly dependent on local characteristics of the domain of study, namely the latitude, longitude and altitude of the observation sites, as well as other locally defined covariate information. In this work, we provide a flexible and computationally feasible way for allowing the correlation structure of the underlying processes to depend on local covariate information. We discuss the properties of the induced covariance functions and discuss methods to assess its dependence on local covariate information by means of a simulation study and the analysis of data observed at ozone-monitoring stations in the Southeast United States. PMID:24772199

ENDF-6 File 30: Data covariances obtained from parameter covariances and sensitivities

International Nuclear Information System (INIS)

Muir, D.W.

1989-01-01

File 30 is provided as a means of describing the covariances of tabulated cross sections, multiplicities, and energy-angle distributions that result from propagating the covariances of a set of underlying parameters (for example, the input parameters of a nuclear-model code), using an evaluator-supplied set of parameter covariances and sensitivities. Whenever nuclear data are evaluated primarily through the application of nuclear models, the covariances of the resulting data can be described very adequately, and compactly, by specifying the covariance matrix for the underlying nuclear parameters, along with a set of sensitivity coefficients giving the rate of change of each nuclear datum of interest with respect to each of the model parameters. Although motivated primarily by these applications of nuclear theory, use of File 30 is not restricted to any one particular evaluation methodology. It can be used to describe data covariances of any origin, so long as they can be formally separated into a set of parameters with specified covariances and a set of data sensitivities

Prevalence of cognitive impairment in individuals aged over 65 in an urban area: DERIVA study

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Rodríguez-Sánchez Emiliano

2011-11-01

Full Text Available Abstract Background Few data are available on the prevalence of cognitive impairment (CI in Spain, and the existing information shows important variations depending on the geographical setting and the methodology employed. The aim of this study was to determine the prevalence of CI in individuals aged over 65 in an urban area, and to analyze its associated risk factors. Methods Design: A descriptive, cross-sectional, home questionnaire-based study; Setting: Populational, urban setting. Participants: The reference population comprised over-65s living in the city of Salamanca (Spain in 2009. Randomized sampling stratified according to health district was carried out, and a total of 480 people were selected. In all, 327 patients were interviewed (68.10%, with a mean age of 76.35 years (SD: 7.33. Women accounted for 64.5% of the total. Measurements: A home health questionnaire was used to obtain the following data: age, sex, educational level, family structure, morbidity and functionality. All participants completed a neuropsychological test battery. The prevalence data were compared with those of the European population, with direct adjustment for age and sex. Diagnoses were divided into three general categories: normal cognitive function, cognitive impairment - no dementia (CIND, and dementia. Results The prevalence of CI among these over-65s was 19% (14.7% CIND and 4.3% dementia. The age-and sex-adjusted global prevalence of CI was 14.9%. CI increased with age (p Conclusions The observed raw prevalence of CI was 19% (14.9% after adjusting for age and sex. Older age and the presence of diabetes and anxiety-depression increased the risk of CI, while higher educational level reduced the risk.

Prevalence of depression among a population aged over 45 years in Chiang Mai, Thailand.

Science.gov (United States)

Wangtongkum, Suparus; Sucharitakul, Phongsakorn; Wongjaroen, Sriwanna; Maneechompoo, Suthin

2008-12-01

To determine the prevalence of depression in Thai people of 45 years and over. The presented project was a cross sectional study on the prevalence of depression and cognitive impairment in Chiang Mai. Door-to-door interview technique was assigned in condition with multistage probability random sampling to obtain subjects that represent a population of Chiang Mai. The research was conducted between October 2004 and September 2005. Data were collected on subject that were 45 years old and over. All subjects were selected from all districts in Chiang Mai. Thai Mini Mental State Examination (TMSE) and Thai Beck Depression Inventory (BDI) were used as the assessment tool If the subjects had a TMSE score less than 24 points, it was assumed as a cognitive impairment. One thousand four hundred ninety two people, 610 males and 882 females, were enrolled in the present study. Their mean age was 59.7 +/- 10.4 years (45-88 year). The prevalence of depression only was 29.2%, the prevalence of cognitive impairment only was 5.63% and the prevalence of cognitive impairment with depression was 3.96%. The prevalence of depression increased with age. The prevalence of depression in Thai people of 45 years and over was 29.2% and increased with age.

Partial covariance based functional connectivity computation using Ledoit-Wolf covariance regularization.

Science.gov (United States)

Brier, Matthew R; Mitra, Anish; McCarthy, John E; Ances, Beau M; Snyder, Abraham Z

2015-11-01

Functional connectivity refers to shared signals among brain regions and is typically assessed in a task free state. Functional connectivity commonly is quantified between signal pairs using Pearson correlation. However, resting-state fMRI is a multivariate process exhibiting a complicated covariance structure. Partial covariance assesses the unique variance shared between two brain regions excluding any widely shared variance, hence is appropriate for the analysis of multivariate fMRI datasets. However, calculation of partial covariance requires inversion of the covariance matrix, which, in most functional connectivity studies, is not invertible owing to rank deficiency. Here we apply Ledoit-Wolf shrinkage (L2 regularization) to invert the high dimensional BOLD covariance matrix. We investigate the network organization and brain-state dependence of partial covariance-based functional connectivity. Although RSNs are conventionally defined in terms of shared variance, removal of widely shared variance, surprisingly, improved the separation of RSNs in a spring embedded graphical model. This result suggests that pair-wise unique shared variance plays a heretofore unrecognized role in RSN covariance organization. In addition, application of partial correlation to fMRI data acquired in the eyes open vs. eyes closed states revealed focal changes in uniquely shared variance between the thalamus and visual cortices. This result suggests that partial correlation of resting state BOLD time series reflect functional processes in addition to structural connectivity. Copyright © 2015 Elsevier Inc. All rights reserved.

Brownian distance covariance

OpenAIRE

Székely, Gábor J.; Rizzo, Maria L.

2010-01-01

Distance correlation is a new class of multivariate dependence coefficients applicable to random vectors of arbitrary and not necessarily equal dimension. Distance covariance and distance correlation are analogous to product-moment covariance and correlation, but generalize and extend these classical bivariate measures of dependence. Distance correlation characterizes independence: it is zero if and only if the random vectors are independent. The notion of covariance with...

Prevalence of obesity among students aged 6 to 12 in China: a meta-analysis

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Yue Tian

2015-12-01

Full Text Available Background: In recent years, obesity has become a major public health problem worldwide. It has been estimated that 8% of children are obese. This study evaluates the overall prevalence of obesity in primary students in recent years. Methods: Publications from 2011 and 2015 on the obesity prevalence among primary school students aged 6 to 12 in China were retrieved from the databases PubMed and Wanfang Data. Obesity was defined using the International Obesity Task Force standard body mass index cutoff points established for children. MetaAnalyst 3.13 software was used to calculate the total prevalence of obesity among primary school students in recent years. Results: After evaluation of the quality of the articles, 14 papers were finally included in our study. The pooled prevalence of obesity in students aged 6 to 12 is 10.2% (95% CI: 7.1–14.6%. Conclusion: Our results indicate that obesity is prevalent in students aged 6 to 12 in China. We believe that appropriate measures should be taken to control this situation.

Prevalence, incidence, and age at diagnosis in Marfan Syndrome

DEFF Research Database (Denmark)

Groth, Kristian A; Hove, Hanne; Kyhl, Kasper

2015-01-01

Background: Marfan syndrome is a genetic disorder with considerable morbidity and mortality. Presently, clinicians use the 2010 revised Ghent nosology, which includes optional genetic sequencing of the FBN1 gene, to diagnose patients. So far, only a few studies based on older diagnostic criteria...... have reported a wide range of prevalence and incidence. Our aim was to study prevalence, incidence, and age at diagnosis in patients with Marfan syndrome. Method: Using unique Danish patient-registries, we identified all possible Marfan syndrome patients recorded by the Danish healthcare system (1977......-2014). Following, we confirmed or rejected the diagnosis according to the 2010 revised Ghent nosology. Results: We identified a total of 1628 persons with possible Marfan syndrome. We confirmed the diagnosis in 412, whereof 46 were deceased, yielding a maximum prevalence of 6.5/100,000 at the end of 2014...

Prediction model for prevalence and incidence of advanced age-related macular degeneration based on genetic, demographic, and environmental variables.

Science.gov (United States)

Seddon, Johanna M; Reynolds, Robyn; Maller, Julian; Fagerness, Jesen A; Daly, Mark J; Rosner, Bernard

2009-05-01

The joint effects of genetic, ocular, and environmental variables were evaluated and predictive models for prevalence and incidence of AMD were assessed. Participants in the multicenter Age-Related Eye Disease Study (AREDS) were included in a prospective evaluation of 1446 individuals, of which 279 progressed to advanced AMD (geographic atrophy or neovascular disease) and 1167 did not progress during 6.3 years of follow-up. For prevalent AMD, 509 advanced cases were compared with 222 controls. Covariates for the incidence analysis included age, sex, education, smoking, body mass index (BMI), baseline AMD grade, and the AREDS vitamin-mineral treatment assignment. DNA specimens were evaluated for six variants in five genes related to AMD. Unconditional logistic regression analyses were performed for prevalent and incident advanced AMD. An algorithm was developed and receiver operating characteristic curves and C statistics were calculated to assess the predictive ability of risk scores to discriminate progressors from nonprogressors. All genetic polymorphisms were independently related to prevalence of advanced AMD, controlling for genetic factors, smoking, BMI, and AREDS treatment. Multivariate odds ratios (ORs) were 3.5 (95% confidence interval [CI], 1.7-7.1) for CFH Y402H; 3.7 (95% CI, 1.6-8.4) for CFH rs1410996; 25.4 (95% CI, 8.6-75.1) for LOC387715 A69S (ARMS2); 0.3 (95% CI, 0.1-0.7) for C2 E318D; 0.3 (95% CI, 0.1-0.5) for CFB; and 3.6 (95% CI, 1.4-9.4) for C3 R102G, comparing the homozygous risk/protective genotypes to the referent genotypes. For incident AMD, all these variants except CFB were significantly related to progression to advanced AMD, after controlling for baseline AMD grade and other factors, with ORs from 1.8 to 4.0 for presence of two risk alleles and 0.4 for the protective allele. An interaction was seen between CFH402H and treatment, after controlling for all genotypes. Smoking was independently related to AMD, with a multiplicative joint

The Effect of Age on the Prevalence of Obesity among US Youth with Autism Spectrum Disorder.

Science.gov (United States)

Must, Aviva; Eliasziw, Misha; Phillips, Sarah M; Curtin, Carol; Kral, Tanja V E; Segal, Mary; Sherwood, Nancy E; Sikich, Linmarie; Stanish, Heidi I; Bandini, Linda G

2017-02-01

We sought to assess the association between age and the prevalence of obesity among children with and without autism spectrum disorder (ASD) in the 2011-2012 National Survey of Children's Health. Analyses were restricted to 43,777 children, ages 10-17, with valid measures of parent-reported weight, height, and ASD status. Exploratory analyses describe the impact of sex, race/ethnicity, and household income on the relationship between age and obesity in ASD. Although the overall prevalence of obesity among children with ASD was significantly (p obesity among children with ASD compared with children without ASD increased monotonically from ages 10 to 17 years. This pattern arose due to a consistently high prevalence of obesity among children with ASD and a decline in prevalence with advancing age among children without ASD. These findings were replicated using a propensity score analysis. Exploratory analyses suggested that the age-related change in obesity disparity between children with and without ASD may be further modified by sex, race/ethnicity, and household income. The patterns of prevalence observed with increasing age among children with and without ASD were unexpected. A better understanding of the etiological and maintenance factors for obesity in youth with ASD is needed to develop interventions tailored to the specific needs of these children.

Covariant representations of nuclear *-algebras

International Nuclear Information System (INIS)

Moore, S.M.

1978-01-01

Extensions of the Csup(*)-algebra theory for covariant representations to nuclear *-algebra are considered. Irreducible covariant representations are essentially unique, an invariant state produces a covariant representation with stable vacuum, and the usual relation between ergodic states and covariant representations holds. There exist construction and decomposition theorems and a possible relation between derivations and covariant representations

COMPONENTS OF (COVARIANCE FOR AGE AT FIRST AND SECOND CALVING OF NELLORE FEMALES RAISED IN SOUTHERN BRAZIL

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Dionéia Magda Everling

2015-10-01

Full Text Available The objective of this study was to estimate the heritability, genetic correlation and estimated breeding values for age at first (AFC and second calving (ASC for Nellore females raised in Southern Brazil. The (covariance and estimated breeding values were obtained using Bayesian inference in a bivariate analysis, adopting an animal model. The average ages were 49.30 and 69.85 months, and the heritabilities were 0.25 and 0.26, respectively for AFC and ASC. The genetic correlation between AFC and ASC was 0.88. The correlation between the classifications of sires according to their estimated breeding values was 0.93. The heritability estimates for AFC and ASC suggest the possibility of obtaining genetic gain by selection. The correlation between these traits close to one indicates that they are controlled by virtually the same genes and when selected for one will advance correlated gain for the other.

Earth Observing System Covariance Realism

Science.gov (United States)

Zaidi, Waqar H.; Hejduk, Matthew D.

2016-01-01

The purpose of covariance realism is to properly size a primary object's covariance in order to add validity to the calculation of the probability of collision. The covariance realism technique in this paper consists of three parts: collection/calculation of definitive state estimates through orbit determination, calculation of covariance realism test statistics at each covariance propagation point, and proper assessment of those test statistics. An empirical cumulative distribution function (ECDF) Goodness-of-Fit (GOF) method is employed to determine if a covariance is properly sized by comparing the empirical distribution of Mahalanobis distance calculations to the hypothesized parent 3-DoF chi-squared distribution. To realistically size a covariance for collision probability calculations, this study uses a state noise compensation algorithm that adds process noise to the definitive epoch covariance to account for uncertainty in the force model. Process noise is added until the GOF tests pass a group significance level threshold. The results of this study indicate that when outliers attributed to persistently high or extreme levels of solar activity are removed, the aforementioned covariance realism compensation method produces a tuned covariance with up to 80 to 90% of the covariance propagation timespan passing (against a 60% minimum passing threshold) the GOF tests-a quite satisfactory and useful result.

An examination of healthy aging across a conceptual continuum: prevalence estimates, demographic patterns, and validity.

Science.gov (United States)

McLaughlin, Sara J; Jette, Alan M; Connell, Cathleen M

2012-06-01

Although the notion of healthy aging has gained wide acceptance in gerontology, measuring the phenomenon is challenging. Guided by a prominent conceptualization of healthy aging, we examined how shifting from a more to less stringent definition of healthy aging influences prevalence estimates, demographic patterns, and validity. Data are from adults aged 65 years and older who participated in the Health and Retirement Study. We examined four operational definitions of healthy aging. For each, we calculated prevalence estimates and examined the odds of healthy aging by age, education, gender, and race-ethnicity in 2006. We also examined the association between healthy aging and both self-rated health and death. Across definitions, the prevalence of healthy aging ranged from 3.3% to 35.5%. For all definitions, those classified as experiencing healthy aging had lower odds of fair or poor self-rated health and death over an 8-year period. The odds of being classified as "healthy" were lower among those of advanced age, those with less education, and women than for their corresponding counterparts across all definitions. Moving across the conceptual continuum--from a more to less rigid definition of healthy aging--markedly increases the measured prevalence of healthy aging. Importantly, results suggest that all examined definitions identified a subgroup of older adults who had substantially lower odds of reporting fair or poor health and dying over an 8-year period, providing evidence of the validity of our definitions. Conceptualizations that emphasize symptomatic disease and functional health may be particularly useful for public health purposes.

Aging, not menopause, is associated with higher prevalence of hyperuricemia among older women.

Science.gov (United States)

Krishnan, Eswar; Bennett, Mihoko; Chen, Linjun

2014-11-01

This work aims to study the associations, if any, of hyperuricemia, gout, and menopause status in the US population. Using multiyear data from the National Health and Nutrition Examination Survey, we performed unmatched comparisons and one to three age-matched comparisons of women aged 20 to 70 years with and without hyperuricemia (serum urate ≥6 mg/dL). Analyses were performed using survey-weighted multiple logistic regression and conditional logistic regression, respectively. Overall, there were 1,477 women with hyperuricemia. Age and serum urate were significantly correlated. In unmatched analyses (n = 9,573 controls), postmenopausal women were older, were heavier, and had higher prevalence of renal impairment, hypertension, diabetes, and hyperlipidemia. In multivariable regression, after accounting for age, body mass index, glomerular filtration rate, and diuretic use, menopause was associated with hyperuricemia (odds ratio, 1.36; 95% CI, 1.05-1.76; P = 0.002). In corresponding multivariable regression using age-matched data (n = 4,431 controls), the odds ratio for menopause was 0.94 (95% CI, 0.83-1.06). Current use of hormone therapy was not associated with prevalent hyperuricemia in both unmatched and matched analyses. Age is a better statistical explanation for the higher prevalence of hyperuricemia among older women than menopause status.

Active aging is associated with low prevalence of depressive symptoms among Brazilian older adults.

Science.gov (United States)

Galli, Rosangela; Moriguchi, Emílio Hideyuki; Bruscato, Neide Maria; Horta, Rogerio Lessa; Pattussi, Marcos Pascoal

2016-01-01

Active aging is the process of optimizing opportunities for health, participation and security, aiming to improve quality of life as people age. A series of studies had demonstrated that a lower prevalence of depression is found among more active elderly. To evaluate the association between indicators of active aging and depressive symptoms among the elderly (aged 60 years or more). A population-based cross-sectional study was conducted with 1,006 elderly people (aged 60 years or over) from a small-sized Brazilian municipality. Depressive symptoms were assessed using the Geriatric Depression Scale - 15, with cutoff point ≥ 6 symptoms. Active aging was evaluated using indicators such as: active occupational situation, manual work, reading and physical activities. Data analyses used modified Poisson regression to obtain crude and adjusted prevalence ratios (PR). Most of the elderly people were: white, women and aged between 60 and 74 years. All the indicators of active aging were associated with the outcome. After controlling for socioeconomic, demographic and health variables, elderly people who worked, participated in groups, did manual work and maintained interests such as reading and talking to friends had lower prevalence of depressive symptoms compared to those not doing these activities. Active aging approaches may serve as a valuable mental health promotion strategy aimed at the elderly.

Prevalence, incidence and progression of lumbar spondylosis by gender and age strata.

Science.gov (United States)

Muraki, Shigeyuki; Yoshimura, Noriko; Akune, Toru; Tanaka, Sakae; Takahashi, Ikuno; Fujiwara, Saeko

2014-07-01

To identify the prevalence, incidence and progression of radiographic lumbar spondylosis (LS). From the Adult Health Study conducted by the Radiation Effects Research Foundation, 1,204 participants aged 44-85 years who had lumbar spine radiographs in 1990-1992 were reexamined in 1998-2000 (mean 7.9-year interval). The radiographic severity of LS was determined by Kellgren/Lawrence (KL) grading. In the overall population, the prevalence of radiographic KL ≥ 2 and ≥ 3 LS was 52.9% and 23.6%, respectively. KL ≥ 2 LS was more prevalent in men, whereas KL ≥ 3 LS was more prevalent in women. During the 8-year follow-up, the incidence of KL ≥ 2 LS in men and women was 65.5% and 46.6%, that of KL ≥ 3 LS was 27.3% and 29.5%, that of progressive LS was 31.3% and 34.0%, and multilevel LS was 44.9% and 33.4%, respectively. Body-mass index was a risk factor for both KL ≥ 2 and KL ≥ 3 LS, after adjusting for age and sex. The present longitudinal study revealed the prevalence, incidence and progression of radiographic LS. Prevalence and incidence of KL ≥ 2 LS was higher in men than women, while, those of KL ≥ 3 were similar between men and women.

Age-specific symptom prevalence in women 35–64 years old: A population-based study

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Wedel Hans

2009-01-01

Full Text Available Abstract Background Symptom prevalence is generally believed to increase with age. The aim of this study was to evaluate the age specific prevalence of 30 general symptoms among Swedish middle-aged women. Methods A cross-sectional postal questionnaire study in seven Swedish counties in a random sample of 4,200 women 35–64 years old, with 2,991 responders. Thirty general symptoms included in the Complaint Score subscale of the Gothenburg Quality of Life Instrument were used. Results Four groups of age specific prevalence patterns were identified after adjustment for the influence of educational level, perceived health and mood, body mass index, smoking habits, use of hormone replacement therapy, and use of other symptom relieving therapy. Only five symptoms (insomnia, leg pain, joint pain, eye problems and impaired hearing increased significantly with age. Eleven symptoms (general fatigue, headache, irritability, melancholy, backache, exhaustion, feels cold, cries easily, abdominal pain, dizziness, and nausea decreased significantly with age. Two symptoms (sweating and impaired concentration had a biphasic course with a significant increase followed by a significant decrease. The remaining twelve symptoms (difficulty in relaxing, restlessness, overweight, coughing, breathlessness, diarrhoea, chest pain, constipation, nervousness, poor appetite, weight loss, and difficulty in urinating had stable prevalence with age. Conclusion Symptoms did not necessarily increase with age instead symptoms related to stress-tension-depression decreased.

Hippocampal sclerosis of aging, a prevalent and high-morbidity brain disease

Science.gov (United States)

Smith, Charles D.; Abner, Erin L.; Wilfred, Bernard J.; Wang, Wang-Xia; Neltner, Janna H.; Baker, Michael; Fardo, David W.; Kryscio, Richard J.; Scheff, Stephen W.; Jicha, Gregory A.; Jellinger, Kurt A.; Van Eldik, Linda J.; Schmitt, Frederick A.

2013-01-01

Hippocampal sclerosis of aging (HS-Aging) is a causative factor in a large proportion of elderly dementia cases. The current definition of HS-Aging rests on pathologic criteria: neuronal loss and gliosis in the hippocampal formation that is out of proportion to AD-type pathology. HS-Aging is also strongly associated with TDP-43 pathology. HS-Aging pathology appears to be most prevalent in the oldest-old: autopsy series indicate that 5–30 % of nonagenarians have HS-Aging pathology. Among prior studies, differences in study design have contributed to the study-to-study variability in reported disease prevalence. The presence of HS-Aging pathology correlates with significant cognitive impairment which is often misdiagnosed as AD clinically. The antemortem diagnosis is further confounded by other diseases linked to hippocampal atrophy including frontotemporal lobar degeneration and cerebrovascular pathologies. Recent advances characterizing the neurocognitive profile of HS-Aging patients have begun to provide clues that may help identify living individuals with HS-Aging pathology. Structural brain imaging studies of research subjects followed to autopsy reveal hippocampal atrophy that is substantially greater in people with eventual HS-Aging pathology, compared to those with AD pathology alone. Data are presented from individuals who were followed with neurocognitive and neuroradiologic measurements, followed by neuropathologic evaluation at the University of Kentucky. Finally, we discuss factors that are hypothesized to cause or modify the disease. We conclude that the published literature on HS-Aging provides strong evidence of an important and under-appreciated brain disease of aging. Unfortunately, there is no therapy or preventive strategy currently available. PMID:23864344

Variations in the prevalence of childhood asthma and wheeze in MeDALL cohorts in Europe

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Eleonora P. Uphoff

2017-07-01

Full Text Available While there is evidence for variations in prevalence rates of childhood wheeze and asthma between countries, longitudinal, individual-level data are needed to understand these differences. The aim of this study was to examine variations in prevalence rates of childhood asthma, wheeze and wheeze with asthma in Europe. We analysed datasets from 10 MeDALL (Mechanisms of the Development of ALLergy cohorts in eight countries, representing 26 663 children, to calculate prevalence rates of wheeze and asthma by child age and wheeze with asthma at age 4 years. Harmonised variables included outcomes parent-reported wheeze and parent-reported doctor-diagnosed asthma, and covariates maternal education, parental smoking, pets, parental asthma, doctor-diagnosed allergic rhinitis, doctor-diagnosed eczema and wheeze severity. At age 4 years, asthma prevalence varied from 1.72% in Germany to 13.48% in England and the prevalence of wheeze varied from 9.82% in Greece to 55.37% in Spain. Adjusted estimates of the proportion of 4-year-old children with wheeze diagnosed with asthma remained highest in England (38.14%, 95% CI 31.38–44.90% and lowest in Spain (15.94%, 95% CI 6.16–25.71%. The large differences in prevalence rates of asthma, wheeze and wheeze with asthma at age 4 years between European cohorts may indicate that childhood asthma is more readily diagnosed in some countries while going unrecognised elsewhere.

The Impact of Survey and Response Modes on Current Smoking Prevalence Estimates Using TUS-CPS: 1992-2003

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Julia Soulakova

2009-12-01

Full Text Available This study identified whether survey administration mode (telephone or in-person and respondent type (self or proxy result in discrepant prevalence of current smoking in the adult U.S. population, while controlling for key sociodemographic characteristics and longitudinal changes of smoking prevalence over the 11-year period from 1992-2003. We used a multiple logistic regression analysis with replicate weights to model the current smoking status logit as a function of a number of covariates. The final model included individual- and family-level sociodemographic characteristics, survey attributes, and multiple two-way interactions of survey mode and respondent type with other covariates. The respondent type is a significant predictor of current smoking prevalence and the magnitude of the difference depends on the age, sex, and education of the person whose smoking status is being reported. Furthermore, the survey mode has significant interactions with survey year, sex, and age. We conclude that using an overall unadjusted estimate of the current smoking prevalence may result in underestimating the current smoking rate when conducting proxy or telephone interviews especially for some sub-populations, such as young adults. We propose that estimates could be improved if more detailed information regarding the respondent type and survey administration mode characteristics were considered in addition to commonly used survey year and sociodemographic characteristics. This information is critical given that future surveillance is moving toward more complex designs. Thus, adjustment of estimates should be contemplated when comparing current smoking prevalence results within a given survey series with major changes in methodology over time and between different surveys using various modes and respondent types.

The prevalence, age distribution and comorbidity of personality disorders in Australian women.

Science.gov (United States)

Quirk, Shae E; Berk, Michael; Pasco, Julie A; Brennan-Olsen, Sharon L; Chanen, Andrew M; Koivumaa-Honkanen, Heli; Burke, Lisa M; Jackson, Henry J; Hulbert, Carol; A Olsson, Craig; Moran, Paul; Stuart, Amanda L; Williams, Lana J

2017-02-01

We aimed to describe the prevalence and age distribution of personality disorders and their comorbidity with other psychiatric disorders in an age-stratified sample of Australian women aged ⩾25 years. Individual personality disorders (paranoid, schizoid, schizotypal, histrionic, narcissistic, borderline, antisocial, avoidant, dependent, obsessive-compulsive), lifetime mood, anxiety, eating and substance misuse disorders were diagnosed utilising validated semi-structured clinical interviews (Structured Clinical Interview for DSM-IV-TR Axis I Disorders, Research Version, Non-patient Edition and Structured Clinical Interview for DSM-IV Axis II Personality Disorders). The prevalence of personality disorders and Clusters were determined from the study population ( n = 768), and standardised to the Australian population using the 2011 Australian Bureau of Statistics census data. Prevalence by age and the association with mood, anxiety, eating and substance misuse disorders was also examined. The overall prevalence of personality disorders in women was 21.8% (95% confidence interval [CI]: 18.7, 24.9). Cluster C personality disorders (17.5%, 95% CI: 16.0, 18.9) were more common than Cluster A (5.3%, 95% CI: 3.5, 7.0) and Cluster B personality disorders (3.2%, 95% CI: 1.8, 4.6). Of the individual personality disorders, obsessive-compulsive (10.3%, 95% CI: 8.0, 12.6), avoidant (9.3%, 95% CI: 7.1, 11.5), paranoid (3.9%, 95% CI: 3.1, 4.7) and borderline (2.7%, 95% CI: 1.4, 4.0) were among the most prevalent. The prevalence of other personality disorders was low (⩽1.7%). Being younger (25-34 years) was predictive of having any personality disorder (odds ratio: 2.36, 95% CI: 1.18, 4.74), as was being middle-aged (odds ratio: 2.41, 95% CI: 1.23, 4.72). Among the strongest predictors of having any personality disorder was having a lifetime history of psychiatric disorders (odds ratio: 4.29, 95% CI: 2.90, 6.33). Mood and anxiety disorders were the most common comorbid

Specific and unspecific gynecological alarm symptoms -prevalence estimates in different age groups

DEFF Research Database (Denmark)

Balasubramaniam, Kirubakaran; Ravn, Pernille; Larsen, Pia V

2015-01-01

OBJECTIVE: To determine prevalence estimates of gynecological alarm symptoms in different age groups and to describe common patterns of gynecological symptoms. DESIGN: Web-based cross-sectional survey study. SETTING: Nationwide in Denmark. POPULATION: A random sample of 51 090 women aged 20 years...

Prevalence and risk factors for HIV among people aged 50 years ...

African Journals Online (AJOL)

Background: It is estimated that over ten percent of the 36.7 million people living with HIV (PLWHIV) globally, are those aged ≥50 years. The objective of this study was to determine the prevalence and risk factors for HIV among adult aged 50 years and above in Rombo district, northern Tanzania. Methods: This cross ...

Covariant field equations in supergravity

Energy Technology Data Exchange (ETDEWEB)

Vanhecke, Bram [KU Leuven, Institute for Theoretical Physics, Leuven (Belgium); Ghent University, Faculty of Physics, Gent (Belgium); Proeyen, Antoine van [KU Leuven, Institute for Theoretical Physics, Leuven (Belgium)

2017-12-15

Covariance is a useful property for handling supergravity theories. In this paper, we prove a covariance property of supergravity field equations: under reasonable conditions, field equations of supergravity are covariant modulo other field equations. We prove that for any supergravity there exist such covariant equations of motion, other than the regular equations of motion, that are equivalent to the latter. The relations that we find between field equations and their covariant form can be used to obtain multiplets of field equations. In practice, the covariant field equations are easily found by simply covariantizing the ordinary field equations. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Covariant field equations in supergravity

International Nuclear Information System (INIS)

Vanhecke, Bram; Proeyen, Antoine van

2017-01-01

Covariance is a useful property for handling supergravity theories. In this paper, we prove a covariance property of supergravity field equations: under reasonable conditions, field equations of supergravity are covariant modulo other field equations. We prove that for any supergravity there exist such covariant equations of motion, other than the regular equations of motion, that are equivalent to the latter. The relations that we find between field equations and their covariant form can be used to obtain multiplets of field equations. In practice, the covariant field equations are easily found by simply covariantizing the ordinary field equations. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Trends in smoking prevalence in Danish adults, 1964-1994. The influence of gender, age, and education

DEFF Research Database (Denmark)

Osler, M; Prescott, E; Gottschau, A

1998-01-01

BACKGROUND: Studies of time trends in smoking prevalence provide a better understanding of the determinants of smoking. The present study analyses changes over time in the prevalence of smoking and heavy smoking in relation to sex, age, and education. METHODS: Data on smoking behaviour were...... collected by questionnaire in random samples of the general population in the area of Copenhagen. The database used included 71,842 measurements of smoking behaviour for 32,156 subjects aged 30 years or more, who had been examined at intervals between 1964 and 1994. In bi- and multivariate analyses...... the effects of sex, age, education, time period, and study group on the prevalence of smoking and of heavy smoking were assessed. RESULTS: Smoking was least prevalent in women, in the oldest age group (more than 70 years), and among those with 8 years or more of school education. During the study period (from...

Moderating the Covariance Between Family Member’s Substance Use Behavior

Science.gov (United States)

Eaves, Lindon J.; Neale, Michael C.

2014-01-01

Twin and family studies implicitly assume that the covariation between family members remains constant across differences in age between the members of the family. However, age-specificity in gene expression for shared environmental factors could generate higher correlations between family members who are more similar in age. Cohort effects (cohort × genotype or cohort × common environment) could have the same effects, and both potentially reduce effect sizes estimated in genome-wide association studies where the subjects are heterogeneous in age. In this paper we describe a model in which the covariance between twins and non-twin siblings is moderated as a function of age difference. We describe the details of the model and simulate data using a variety of different parameter values to demonstrate that model fitting returns unbiased parameter estimates. Power analyses are then conducted to estimate the sample sizes required to detect the effects of moderation in a design of twins and siblings. Finally, the model is applied to data on cigarette smoking. We find that (1) the model effectively recovers the simulated parameters, (2) the power is relatively low and therefore requires large sample sizes before small to moderate effect sizes can be found reliably, and (3) the genetic covariance between siblings for smoking behavior decays very rapidly. Result 3 implies that, e.g., genome-wide studies of smoking behavior that use individuals assessed at different ages, or belonging to different birth-year cohorts may have had substantially reduced power to detect effects of genotype on cigarette use. It also implies that significant special twin environmental effects can be explained by age-moderation in some cases. This effect likely contributes to the missing heritability paradox. PMID:24647834

PREVALENCE AND ASSOCIATED FACTORS OF FLATFOOT AMONG 6 TO 10 AGED CHILDREN IN CENTRAL PROVINCE OF SRI LANKA

Directory of Open Access Journals (Sweden)

V.V. Senadheera

2016-06-01

Full Text Available Background: Prevalence of flatfoot is highly variable in different world populations. Previous studies have found that many factors are associated with flatfoot. The objective of the present study was to investigate the prevalence of flatfoot and its association with age, gender and BMI in group of 6-10 aged children in Central province of Sri Lanka. Methods: A total of 722 children aged 6 to 10 were used to assess normalize navicular height using two clinical measurements (navicular height, truncated foot length. Weight and height of the subjects were measured to calculate body mass index. Age and gender of the children were also recorded. Calculated normalize navicular heights were plotted in a distribution curve and area under the curve between +1SD and -1SD was considered as normal foot. Area under the curve which is left to the -1SD was considered as flatfoot. Results: Overall prevalence of flatfoot among 6-10 aged children in the present sample was 16.06%. The prevalence of flatfoot in 6,7,8,9 and 10 aged children were 26.35%, 16.19%, 12.75%, 13.57% and 11.1%, respectively. Prevalence of flatfoot was high in overweight children (21.05%. Prevalence of flatfoot among males and females were 47% and 53%,respectively. Conclusion: This study suggests that there is a significant association between flatfoot and age (p<0.05. Prevalence of flat foot decreases with advancing age. Furthermore, there is a significant association between flatfoot and body mass index (p<0.05. Prevalence of flatfoot is higher in overweight children than normal weight and underweight children. There is no significant association between flatfoot and gender.

Prevalence of cognitive impairment in individuals aged over 65 in an urban area: DERIVA study.

Science.gov (United States)

Rodríguez-Sánchez, Emiliano; Mora-Simón, Sara; Patino-Alonso, María C; García-García, Ricardo; Escribano-Hernández, Alfonso; García-Ortiz, Luis; Perea-Bartolomé, Ma Victoria; Gómez-Marcos, Manuel A

2011-11-17

Few data are available on the prevalence of cognitive impairment (CI) in Spain, and the existing information shows important variations depending on the geographical setting and the methodology employed. The aim of this study was to determine the prevalence of CI in individuals aged over 65 in an urban area, and to analyze its associated risk factors. A descriptive, cross-sectional, home questionnaire-based study; Populational, urban setting. The reference population comprised over-65s living in the city of Salamanca (Spain) in 2009. Randomized sampling stratified according to health district was carried out, and a total of 480 people were selected. In all, 327 patients were interviewed (68.10%), with a mean age of 76.35 years (SD: 7.33). Women accounted for 64.5% of the total. A home health questionnaire was used to obtain the following data: age, sex, educational level, family structure, morbidity and functionality. All participants completed a neuropsychological test battery. The prevalence data were compared with those of the European population, with direct adjustment for age and sex. Diagnoses were divided into three general categories: normal cognitive function, cognitive impairment - no dementia (CIND), and dementia. The prevalence of CI among these over-65s was 19% (14.7% CIND and 4.3% dementia). The age-and sex-adjusted global prevalence of CI was 14.9%. CI increased with age (p < 0.001) and decreased with increasing educational level (p < 0.001). Significant risk factors were found with the multivariate analyses: age (OR = 1.08, 95%CI: 1.03-1.12), anxiety-depression (OR = 3.47, 95%CI: 1.61-7.51) and diabetes (OR = 2.07, 95%CI: 1.02-4.18). In turn, years of education was found to be a protective factor (OR = 0.79, 95%CI: 0.70-0.90). Although CI was more frequent among women and in people living without a partner, these characteristics were not significantly associated with CI risk. The observed raw prevalence of CI was 19% (14.9% after adjusting for age

A special covariance structure for random coefficient models with both between and within covariates

International Nuclear Information System (INIS)

Riedel, K.S.

1990-07-01

We review random coefficient (RC) models in linear regression and propose a bias correction to the maximum likelihood (ML) estimator. Asymmptotic expansion of the ML equations are given when the between individual variance is much larger or smaller than the variance from within individual fluctuations. The standard model assumes all but one covariate varies within each individual, (we denote the within covariates by vector χ 1 ). We consider random coefficient models where some of the covariates do not vary in any single individual (we denote the between covariates by vector χ 0 ). The regression coefficients, vector β k , can only be estimated in the subspace X k of X. Thus the number of individuals necessary to estimate vector β and the covariance matrix Δ of vector β increases significantly in the presence of more than one between covariate. When the number of individuals is sufficient to estimate vector β but not the entire matrix Δ , additional assumptions must be imposed on the structure of Δ. A simple reduced model is that the between component of vector β is fixed and only the within component varies randomly. This model fails because it is not invariant under linear coordinate transformations and it can significantly overestimate the variance of new observations. We propose a covariance structure for Δ without these difficulties by first projecting the within covariates onto the space perpendicular to be between covariates. (orig.)

Prevalence and risk factors for HIV among people aged 50 years ...

African Journals Online (AJOL)

JOHN

reproductive and sexual health characteristics of the participants, knowledge on HIV ... Keywords: HIV, older adults, prevalence, knowledge, risk factors, Tanzania ... With increased availability of ART, people are living longer and age with HIV ...

Ethnic differences in age of onset and prevalence of disordered ...

African Journals Online (AJOL)

Conclusion: This study fills the hiatus in the existing South African literature with respect to age of onset and prevalence of disordered eating attitudes and behaviours across ethnic boundaries. Furthermore, it creates a foundation for developing appropriate strategies to address eating disorders in the multicultural South ...

Prevalence and awareness of obesity among people of different age ...

African Journals Online (AJOL)

Prevalence and awareness of obesity among people of different age groups in educational institutions in Morogoro, Tanzania. ... The four institutions included a primary and a secondary school, a teacher's training college and a university. ... Employed subjects had higher rate of obesity (22.2%) than pupils or students.

Age-specific Prevalence of Antibodies to Hepatitis A in Children and Adolescents from Rio de Janeiro, Brazil, 1978 and 1995: Relationship of Prevalence to Environmental Factors

Directory of Open Access Journals (Sweden)

Claudia L Vitral

1998-01-01

Full Text Available The age-specific prevalence of antibodies to hepatitis A virus (anti-HAV was determined in two different population groups with low socio-economic status from Rio de Janeiro city, Brazil, whose serum samples were collected 17 years apart (Population 1, 1978; Population 2, 1995. In Population 2, analysis of the anti-HAV prevalence was also carried out with respect to environmental factors. Population 1 was composed of 520 stored sera collected from the umbilical cord of term neonates and children aged 1 month to 6 years. In population 2, 720 serum samples were collected from children and adolescents with ages ranging from 1 to 23 years. The overall prevalence rate of anti-HAV in Population 1 and Population 2 was 65.6% and 32.1%, respectively. In Population 1, the anti-HAV prevalence reached 88% at the age of 3, while in Population 2, it increased from 4.5% in children under the age of 3 to 66% in the group of adolescents over the age of 14. The low exposure to HAV infection in younger children from Population 2 could be a result of improved environmental hygiene and sanitation, as demonstrated by the presence of piped water, waste and sewage disposal systems in most houses from this population group. These findings indicate a possible change in the prevalence of hepatitis A in Rio de Janeiro

Covariant w∞ gravity

NARCIS (Netherlands)

Bergshoeff, E.; Pope, C.N.; Stelle, K.S.

1990-01-01

We discuss the notion of higher-spin covariance in w∞ gravity. We show how a recently proposed covariant w∞ gravity action can be obtained from non-chiral w∞ gravity by making field redefinitions that introduce new gauge-field components with corresponding new gauge transformations.

Prevalence of toxoplasma antibodies according to age with comments on the risk of prenatal infection.

OpenAIRE

van der Veen, J.; Polak, M. F.

1980-01-01

Sera from 1661 persons in 12 age groups from 0 to 79 years were titrated for toxoplasma antibodies in the indirect immunofluorescence test. The sera were collected from patients with symptoms suggestive of acute, mainly respiratory, viral infections. After the first year of life, the prevalence of antibodies started to rise, reaching 59% between 40 and 79 years of age. From the prevalence of antibodies in different age groups the annual infection risk, i.e, the risk of a non-immune person acq...

National Trends in Hemoglobin Concentration and Prevalence of Anemia among Chinese School-Aged Children, 1995-2010.

Science.gov (United States)

Song, Yi; Wang, Hai-Jun; Dong, Bin; Wang, Zhiqiang; Ma, Jun; Agardh, Anette

2017-04-01

To assess the trend of sex disparity in hemoglobin concentration and prevalence of anemia among Chinese school-aged children from 1995 to 2010. Data were collected from 360 866 children aged 7, 9, 12, 14, and 17 years during 4 cross-sectional surveys (1995, 2000, 2005, and 2010) of the Chinese National Surveys on Students Constitution and Health. Shifts in hemoglobin concentration distributions were compared by sex. Average shifts and sex differences were calculated with quantile regression models. Logistic regression was used to estimate the prevalence odds ratio of sex for prevalence of anemia in different surveys. The mean hemoglobin concentration increased among Chinese children between 1995 and 2010, from 132.7 to 138.3 g/L in boys, and from 127.7 to 132.3 g/L in girls. The prevalence of anemia decreased from 18.8% in 1995 to 9.9% in 2010. It was higher in rural than urban children among all age groups. The prevalence odds ratios of girls versus boys for anemia increased in both urban and rural areas over time. Hemoglobin concentration and prevalence of anemia improved among Chinese school-aged children over time. Hemoglobin concentration improved faster in boys than girls and as a result the relative prevalence of anemia in girls compared with boys increased. Sex-specific preventive guidelines and public health policies for childhood anemia are needed in China. Copyright © 2017 Elsevier Inc. All rights reserved.

Prevalence of corneal astigmatism in Tohono O'odham Native American children 6 months to 8 years of age.

Science.gov (United States)

Harvey, Erin M; Dobson, Velma; Miller, Joseph M; Schwiegerling, Jim; Clifford-Donaldson, Candice E; Green, Tina K; Messer, Dawn H

2011-06-21

To describe the prevalence of corneal astigmatism in infants and young children who are members of a Native American tribe with a high prevalence of refractive astigmatism. The prevalence of corneal astigmatism was assessed by obtaining infant keratometer (IK4) measurements from 1235 Tohono O'odham children, aged 6 months to 8 years. The prevalence of corneal astigmatism >2.00 D was lower in the 1- to <2-year-old age group when compared with all other age groups, except the 6- to <7-year-old group. The magnitude of mean corneal astigmatism was significantly lower in the 1- to <2-year age group than in the 5- to <6-, 6- to <7-, and 7- to <8-year age groups. Corneal astigmatism was with-the-rule (WTR) in 91.4% of astigmatic children (≥1.00 D). The prevalence and mean amount of corneal astigmatism were higher than reported in non-Native American populations. Mean astigmatism increased from 1.43 D in 1-year-olds to nearly 2.00 D by school age.

[Prevalence of negative stereotypes towards old age among personnel of a general hospital].

Science.gov (United States)

Franco S, Mireya; Villarreal R, Enrique; Vargas D, Emma R; Martínez G, Lidia; Galicia R, Liliana

2010-08-01

Social representations are value systems. Social stereotypes are a social consensus of traits associated with a specific group. Stereotypes about older subjects, generally have negative connotations. To assess the prevalence of negative stereotypes towards older subjects among health care personnel. A questionnaire about stereotypes towards old age, with Likert type questions that included health, social motivations and personality-character domains, was applied to 52 doctors, 12 residents, 80 general nurses, 36 auxiliary nurses, four social workers and 10 medical assistants, working at a general hospital. The mean age of the professionals who answered the questionnaire was 38 years (95% confidence intervals (CI) 37-39 years) and 78% were women. The prevalence of a Global negative stereotype was 65.0%(95% CI: 59.5-70.5). The figure for the health domain was 64.5% (IC95%; 59.0-70.0), for the social motivation domain was 60%(5%CI: 54.3-65.7) and for the character personality domain was 64% (95%CI: 58.4-69.6). There is a high prevalence of a negative stereotype towards old age among health care personnel.

Evaluation and processing of covariance data

International Nuclear Information System (INIS)

Wagner, M.

1993-01-01

These proceedings of a specialists'meeting on evaluation and processing of covariance data is divided into 4 parts bearing on: part 1- Needs for evaluated covariance data (2 Papers), part 2- generation of covariance data (15 Papers), part 3- Processing of covariance files (2 Papers), part 4-Experience in the use of evaluated covariance data (2 Papers)

Prevalence of dementia among population age over 45 years in Chiang Mai, Thailand.

Science.gov (United States)

Wangtongkum, Suparus; Sucharitkul, Phongsakorn; Silprasert, Nutcharut; Inthrachak, Rudeethawinl

2008-11-01

To determine the prevalence of dementia in Thai people with age 45 years and above. This project used a cross sectional research design to study the prevalence of dementia in Chiang Mai. Door-to-door technique was assigned in condition with multi-stage probability random sampling to obtain subjects representing the population of Chiang Mai between Oct 2004 and Sep 2005. The researchers collected the data from the subjects aged 45 years and above. All subjects were located from every Amphurs of Chiang Mai. They were first screened with Thai Mini Mental State Examination (TMSE) and Thai Beck Depression Inventory (BDI). The subjects whose TMSE was less than 24 were assessed and diagnosed by a neurologist. Subjects who were determined as having dementia might be laboratory analyzed and classified based on DSM-IV and NINDS-AIREN criteria. The authors enrolled 2,311 people and screened them with Batteries test. One thousand four hundred ninety two people qualified with 610 males and 882 females, whose mean age was 59.7 +/- 10.4 years. The authors found that among the 35 people with dementia, the mean age was 67.9 +/- 8.9 years (45-88 years). The prevalence of dementia among the study participants was 2.35%. In the present study, Alzheimer's disease was the most common type of dementia diagnosed (75.0%) and vascular dementia was the second most commonly diagnosed (12.5%). The prevalence of dementia in Chiang Mai was 2.35%, which does not differ from the previous study Alzheimer's disease was the most common type of dementia diagnosed.

Covariance data processing code. ERRORJ

International Nuclear Information System (INIS)

Kosako, Kazuaki

2001-01-01

The covariance data processing code, ERRORJ, was developed to process the covariance data of JENDL-3.2. ERRORJ has the processing functions of covariance data for cross sections including resonance parameters, angular distribution and energy distribution. (author)

Early selection in open-pollinated Eucalyptus families based on competition covariates

Directory of Open Access Journals (Sweden)

Bruno Ettore Pavan

2014-06-01

Full Text Available The objetive of this work was to evaluate the influence of intergenotypic competition in open-pollinated families of Eucalyptus and its effects on early selection efficiency. Two experiments were carried out, in which the timber volume was evaluated at three ages, in a randomized complete block design. Data from the three years of evaluation (experiment 1, at 2, 4, and 7 years; and experiment 2, at 2, 5, and 7 years were analyzed using mixed models. The following were estimated: variance components, genetic parameters, selection gains, effective number, early selection efficiency, selection gain per unit time, and coincidence of selection with and without the use of competition covariates. Competition effect was nonsignificant for ages under three years, and adjustment using competition covariates was unnecessary. Early selection for families is effective; families that have a late growth spurt are more vulnerable to competition, which markedly impairs ranking at the end of the cycle. Early selection is efficient according to all adopted criteria, and the age of around three years is the most recommended, given the high efficiency and accuracy rate in the indication of trees and families. The addition of competition covariates at the end of the cycle improves early selection efficiency for almost all studied criteria.

Prevalence of molar incisor hypomineralization in school children aged 8-12 years in Chennai

Directory of Open Access Journals (Sweden)

Savitha Deepthi Yannam

2016-01-01

Full Text Available Objective: To investigate the prevalence and severity of molar incisor hypomineralization (MIH. Materials and Methods: A sample of 2,864 students aged 8-12 years were selected from government and private schools in Chennai. MIH was diagnosed clinically based on the diagnostic criteria established by the European Academy of Pediatric Dentistry (EAPD 2003. Results: A total of 277 children (9.7% had MIH. There was statistically significant difference in prevalence related to age but there was no statistical difference in prevalence with respect to gender. Conclusion: Prevalence of MIH was 9.7% in the child population residing in Chennai. Males and females were equally affected. The rate of occurrence and severity of MIH are more in the right mandibular first molar. The severity of MIH is more in molars compared to incisors (P < 0.001 and is more in government schools compared to private schools (P = 0.002.

Prevalence of Hypertension Among Women of Child Bearing Age in ...

African Journals Online (AJOL)

Prevalence of Hypertension Among Women of Child Bearing Age in Zambia. PE Chowa, C Lin, F Goma, J South-Paul. Abstract. Hypertensive disorders of pregnancy account for 12 to 20 percent of the total maternal deaths in the world. Some of these disorders are precipitated by pre-existing chronic hypertension of which ...

[Hepatitis B prevalence among women in child-bearing age in Shandong Province, China, 2014].

Science.gov (United States)

Zhang, L; Liu, J Y; Lyu, J J; Yan, B Y; Feng, Y; Wu, W L; Song, L Z; Xu, A Q

2017-06-06

Objective: To know the prevalence of hepatitis B virus (HBV) among women in child-bearing age in Shandong Province, China, providing references to the improvement of HBV control strategy. Methods: The participants were randomly selected by two-stage sampling method from 12 counties which were representative for the whole province. Firstly two townships were selected from each county by probability proportional to size sampling (PPS) method. Then participants aged 1-4 years, 5-14 years, 15-29 years and 30-59 years were selected by stratified random sampling method. The women in child-bearing age (20-49 years) were involved in this study. Questionnaire survey and 5 ml blood collection were conducted among all participants. Blood samples were detected for hepatitis B surface antigen (HBsAg), antibody against HBsAg (anti-HBs) and antibody against hepatitis B core antigen (anti-HBc). Those who were positive for HBsAg were further detected for hepatitis e antigen (HBeAg), antibody against HBeAg (anti-HBe) and the load of HBV DNA. The basic information of the participants including age, gender, occupation, nationality and residence place were collected. The prevalence of HBV infection indicators after weight adjustment were calculated and compared between participants with different demographic characteristics. Results: A total of 1 151 women in child-bearing age were involved in this study. Twenty-seven participants were positive for HBsAg and the prevalence rate was 2.10% (95 % CI: 0.97%-3.23%). Five participants were positive for both HBsAg and HBeAg and the prevalence rate was 0.36% (95 % CI: 0-0.84%). There were 567 and 291 participants who were positive for anti-HBs and anti-HBc respectively and the corresponding prevalence rates were 47.72% (95 %CI: 41.68%-53.75%) and 24.40% (95 % CI: 18.50%-30.30%). The number of participants susceptible for HBV was 527 and the percentage of HBV susceptible women was 47.55% (95 % CI: 41.63%-53.47%). Conclusion: HBV infection among

Covariance Bell inequalities

Science.gov (United States)

Pozsgay, Victor; Hirsch, Flavien; Branciard, Cyril; Brunner, Nicolas

2017-12-01

We introduce Bell inequalities based on covariance, one of the most common measures of correlation. Explicit examples are discussed, and violations in quantum theory are demonstrated. A crucial feature of these covariance Bell inequalities is their nonlinearity; this has nontrivial consequences for the derivation of their local bound, which is not reached by deterministic local correlations. For our simplest inequality, we derive analytically tight bounds for both local and quantum correlations. An interesting application of covariance Bell inequalities is that they can act as "shared randomness witnesses": specifically, the value of the Bell expression gives device-independent lower bounds on both the dimension and the entropy of the shared random variable in a local model.

Distance covariance for stochastic processes

DEFF Research Database (Denmark)

Matsui, Muneya; Mikosch, Thomas Valentin; Samorodnitsky, Gennady

2017-01-01

The distance covariance of two random vectors is a measure of their dependence. The empirical distance covariance and correlation can be used as statistical tools for testing whether two random vectors are independent. We propose an analog of the distance covariance for two stochastic processes...

Prevalence of hypotension and its association with cognitive function among older adults.

Science.gov (United States)

Momtaz, Yadollah Abolfathi; Hamid, Tengku Aizan; Haron, Sharifah Azizah; Bagat, Mohamad Fazdillah; Mohammadi, Fatemeh

2018-04-01

The negative effect of hypertension has overshadowed possible health problems associated with hypotension. The purposes of this study were to describe the prevalence of hypotension in older adults and to determine the association between hypotension and cognitive function, after adjusting for possible covariates. The data for the study consisting of 1067 community-dwelling older adults were obtained from a national survey entitled "Identifying Psychosocial and Identifying Economic Risk Factor of Cognitive Impairment among Elderly", conducted in Malaysia. The hypotension was considered as blood pressure age of the respondents was 68.27 (SD = 5.93). Mean score of cognitive function as measured by MMSE was 22.70 (SD = 4.95). The prevalence of hypotension was 29.3%. The prevalence of cognitive impairment for hypotension group was 25.6%. Results of multiple linear regression analysis revealed that hypotension is negatively associated with cognitive function (Beta = -0.11, page, gender, education, marital status, employment status, diabetes, heart disease, stroke and gastritis. The study showing hypotension is significantly associated with decreased cognitive function in later life, implies more attention to low blood pressure in old age.

Correlation- and covariance-supported normalization method for estimating orthodontic trainer treatment for clenching activity.

Science.gov (United States)

Akdenur, B; Okkesum, S; Kara, S; Günes, S

2009-11-01

In this study, electromyography signals sampled from children undergoing orthodontic treatment were used to estimate the effect of an orthodontic trainer on the anterior temporal muscle. A novel data normalization method, called the correlation- and covariance-supported normalization method (CCSNM), based on correlation and covariance between features in a data set, is proposed to provide predictive guidance to the orthodontic technique. The method was tested in two stages: first, data normalization using the CCSNM; second, prediction of normalized values of anterior temporal muscles using an artificial neural network (ANN) with a Levenberg-Marquardt learning algorithm. The data set consists of electromyography signals from right anterior temporal muscles, recorded from 20 children aged 8-13 years with class II malocclusion. The signals were recorded at the start and end of a 6-month treatment. In order to train and test the ANN, two-fold cross-validation was used. The CCSNM was compared with four normalization methods: minimum-maximum normalization, z score, decimal scaling, and line base normalization. In order to demonstrate the performance of the proposed method, prevalent performance-measuring methods, and the mean square error and mean absolute error as mathematical methods, the statistical relation factor R2 and the average deviation have been examined. The results show that the CCSNM was the best normalization method among other normalization methods for estimating the effect of the trainer.

Covariance Manipulation for Conjunction Assessment

Science.gov (United States)

Hejduk, M. D.

2016-01-01

The manipulation of space object covariances to try to provide additional or improved information to conjunction risk assessment is not an uncommon practice. Types of manipulation include fabricating a covariance when it is missing or unreliable to force the probability of collision (Pc) to a maximum value ('PcMax'), scaling a covariance to try to improve its realism or see the effect of covariance volatility on the calculated Pc, and constructing the equivalent of an epoch covariance at a convenient future point in the event ('covariance forecasting'). In bringing these methods to bear for Conjunction Assessment (CA) operations, however, some do not remain fully consistent with best practices for conducting risk management, some seem to be of relatively low utility, and some require additional information before they can contribute fully to risk analysis. This study describes some basic principles of modern risk management (following the Kaplan construct) and then examines the PcMax and covariance forecasting paradigms for alignment with these principles; it then further examines the expected utility of these methods in the modern CA framework. Both paradigms are found to be not without utility, but only in situations that are somewhat carefully circumscribed.

Low prevalence of iron deficiency anemia between 1981 and 2010 in Chilean women of childbearing age.

Directory of Open Access Journals (Sweden)

Israel Ríos-Castillo

2013-09-01

Full Text Available Objective. To determine the prevalence of anemia and iron status among Chilean women of childbearing age between 1981 and 2010. Materials and methods. Calculation of the prevalence of anemia and iron status was based on multiple cross-sectional iron absorption studies performed in 888 women during this period of time. All studies included measurements of hemoglobin, mean corpuscular volume, zinc protoporphyrin, percentage of transferrin saturation and serum ferritin. Data were grouped by decade (1981-1990,1991-2000, and 2001-2010. Results. Prevalence of anemia for these decades was 9, 6 and 10%, respectively (p=NS. Iron deficiency anemia was the main cause of anemia in all periods (55, 85 and 75%, respectively; p=NS. A high prevalence of women with normal iron status was observed for all periods (64, 69, and 67, respectively; p=NS. Prevalence of iron deficiency without anemia in 1981-1990, 1991-2000 and 2001-2010 was 7, 20 and 12%, respectively (p menor que 0.05. Finally, prevalence of iron depleted stores was 20, 6 and 10%, respectively (p menor que 0.05. Conclusions. Prevalence of iron deficiency anemia in Chilean women of childbearing age was mild between 1981 and 2010. More than 60% of childbearing age women presented normal iron status in all periods. However, prevalence of iron depleted stores was moderate during 1981-1990, and was mild during 1991-2000 and 2001-2010.

Age and gender effects on the prevalence of poor sleep quality in the adult population.

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Madrid-Valero, Juan J; Martínez-Selva, José M; Ribeiro do Couto, Bruno; Sánchez-Romera, Juan F; Ordoñana, Juan R

Sleep quality has a significant impact on health and quality of life and is affected, among other factors, by age and sex. However, the prevalence of problems in this area in the general population is not well known. Therefore, our objective was to study the prevalence and main characteristics of sleep quality in an adult population sample. 2,144 subjects aged between 43 and 71 years belonging to the Murcia (Spain) Twin Registry. Sleep quality was measured by self-report through the Pittsburgh Sleep Quality Index (PSQI). Logistic regression models were used to analyse the results. The prevalence of poor sleep quality stands at 38.2%. Univariate logistic regression analyses showed that women were almost twice as likely as men (OR: 1.88; 95% confidence interval [95%CI]: 1.54 to 2.28) to have poor quality of sleep. Age was directly and significantly associated with a low quality of sleep (OR: 1.05; 95%CI: 1.03 to 1.06). The prevalence of poor sleep quality is high among adults, especially women. There is a direct relationship between age and deterioration in the quality of sleep. This relationship also appears to be more consistent in women. Copyright © 2016 SESPAS. Publicado por Elsevier España, S.L.U. All rights reserved.

Prevalence of frailty in middle-aged and older community-dwelling Europeans living in 10 countries.

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Santos-Eggimann, Brigitte; Cuénoud, Patrick; Spagnoli, Jacques; Junod, Julien

2009-06-01

Frailty is an indicator of health status in old age. Its frequency has been described mainly for North America; comparable data from other countries are lacking. Here we report on the prevalence of frailty in 10 European countries included in a population-based survey. Cross-sectional analysis of 18,227 randomly selected community-dwelling individuals 50 years of age and older, enrolled in the Survey of Health, Aging and Retirement in Europe (SHARE) in 2004. Complete data for assessing a frailty phenotype (exhaustion, shrinking, weakness, slowness, and low physical activity) were available for 16,584 participants. Prevalences of frailty and prefrailty were estimated for individuals 50-64 years and 65 years of age and older from each country. The latter group was analyzed further after excluding disabled individuals. We estimated country effects in this subset using multivariate logistic regression models, controlling first for age, gender, and then demographics and education. The proportion of frailty (three to five criteria) or prefrailty (one to two criteria) was higher in southern than in northern Europe. International differences in the prevalences of frailty and prefrailty for 65 years and older group persisted after excluding the disabled. Demographic characteristics did not account for international differences; however, education was associated with frailty. Controlling for education, age and gender diminished the effects of residing in Italy and Spain. A higher prevalence of frailty in southern countries is consistent with previous findings of a north-south gradient for other health indicators in SHARE. Our data suggest that socioeconomic factors like education contribute to these differences in frailty and prefrailty.

Low prevalence of depression and anxiety is linked to statutory retirement ages rather than personal work exit: a national survey.

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Villamil, Elena; Huppert, Felicia A; Melzer, David

2006-07-01

Common mental disorder prevalence decreases substantially around the conventional retirement age for men in the UK, but trends for older women are more continuous. Prevalence changes in depression and anxiety around retirement are less clear, as is the role of risk factors. The aim of this study was to establish whether work status, age or other known risk factors account for the reduced prevalence of depressive episode and anxiety disorder around retirement ages for men and for women. The British Psychiatric Morbidity Survey (BPMS) 2000 was analysed, including 1875 men and 2253 women aged 45-75 years. Diagnoses were from the Revised Clinical Interview Schedule (CIS-R). Logistic models were adjusted for sociodemographic factors, social network, work status, life events, physical illness and disability. There are marked reductions in the prevalence of depressive episode after 60 years for women [60% lower prevalence, 95% confidence interval (CI) 40-80] and 65 years for men (90% lower prevalence, 95% CI 70-100), compared to the youngest age groups. For anxiety disorder, the reduction in prevalence was 80% (95% CI 60-90) for men and 40% (95% CI 20-60) for women. In fully adjusted multivariate models, the strong association between diagnoses and age groups remained, for both genders. Work status was a significant factor for men but not for women. There is a discontinuity in the prevalence of depressive episode for both men and women, coinciding with statutory retirement ages. No studied risk factor reduced the associations between age group and disorders. This population scale recovery may provide a model for understanding non-genetic factors.

The prevalence of obesity among school-aged children and youth aged 6-18 years in Iran: A systematic review and meta-analysis study

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Salman Khazaei

2017-03-01

Full Text Available BACKGROUND: Obesity is considered as a major health problem of children and adolescents. The present meta-analysis was conducted by extensive search of studies on the prevalence of obesity among school-aged children and youth aged 6-18 years in Iran. METHODS: All conducted cross-sectional studies on the prevalence of obesity in Iranian students in all grades were extracted, without applying any restriction on time in national and international databases including Magiran, Iranmedex, SID, Scopus, Google Scholar, and PubMed. Statistical software Stata 12 was used to analyze the data and to obtain the prevalence of obesity among Iranian students. The heterogeneity between the results was determined using statistical test I2. RESULTS: In this meta-analysis, 51 papers met our inclusion criteria and were therefore considered for the analysis. The prevalence of obesity was equal to 5.82% [95% confidence interval (CI: 5-6.66] in Iranian students. The prevalence of obesity was higher in boys than in girls (6.85% compared to 5.13% (P = 0.300. The highest prevalence of obesity was related to students living in the North and Northwest areas with 7.07% (95% CI: 4.35-9.78. CONCLUSION: The prevalence of obesity among Iranian students is not high when compared to Western countries. However, due to lifestyle changes in recent years, it is necessary to plan intervention programs within families and schools to improve dietary patterns and physical activity of this age group.  Normal 0 false false false EN-US X-NONE FA

Multiple Imputation of a Randomly Censored Covariate Improves Logistic Regression Analysis.

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Atem, Folefac D; Qian, Jing; Maye, Jacqueline E; Johnson, Keith A; Betensky, Rebecca A

2016-01-01

Randomly censored covariates arise frequently in epidemiologic studies. The most commonly used methods, including complete case and single imputation or substitution, suffer from inefficiency and bias. They make strong parametric assumptions or they consider limit of detection censoring only. We employ multiple imputation, in conjunction with semi-parametric modeling of the censored covariate, to overcome these shortcomings and to facilitate robust estimation. We develop a multiple imputation approach for randomly censored covariates within the framework of a logistic regression model. We use the non-parametric estimate of the covariate distribution or the semiparametric Cox model estimate in the presence of additional covariates in the model. We evaluate this procedure in simulations, and compare its operating characteristics to those from the complete case analysis and a survival regression approach. We apply the procedures to an Alzheimer's study of the association between amyloid positivity and maternal age of onset of dementia. Multiple imputation achieves lower standard errors and higher power than the complete case approach under heavy and moderate censoring and is comparable under light censoring. The survival regression approach achieves the highest power among all procedures, but does not produce interpretable estimates of association. Multiple imputation offers a favorable alternative to complete case analysis and ad hoc substitution methods in the presence of randomly censored covariates within the framework of logistic regression.

Prevalence and Sociodemographic Determinants of Hypertension History among Women in Reproductive Age in Ghana

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Samuel H. Nyarko

2016-01-01

Full Text Available Background. Hypertension is a global health problem. Yet, studies on hypertension rarely focus on women in Ghana. The purpose of this study is to ascertain the prevalence and sociodemographic determinants of hypertension history among Ghanaian women in reproductive age. Methods. This study used data from the 2014 Ghana Demographic and Health Survey. Bivariate and logistic regression analyses were carried out to ascertain the prevalence and determinants of hypertension history among the respondents. Results. The study found that the overall prevalence of hypertension history among the respondents was 7.5%; however, there were vast variations within most of the sociodemographic categories. Age, level of education, marital status, work status, and wealth status had a significant relationship with hypertension history among the respondents. Women in advanced age groups, highly educated, married, and widowed/divorced/separated, nonworking women, and women from wealthy households were at higher risk of having hypertension history. Conclusion. Myriads of sociodemographic factors determine the hypertension history of women in Ghana. It is therefore essential to target medical and psychosocial hypertension interventions at Ghanaian women in the higher risk groups.

Prevalence of metabolic syndrome in adolescents aged 10-18 years in Jammu, J and K

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Narinder Singh

2013-01-01

Full Text Available Objective: To estimate the prevalence of metabolic syndrome among adolescents attending school in the Jammu region, India. Materials and Methods: This is a cross-sectional study conducted between November 2009 and December 2010, among a total of 1160 school-going adolescents of both sexes aged 10-18 years. Relevant metabolic and anthropometric variables were analyzed and criteria suggested by National Cholesterol Education Program Adult Treatment Panel Third (NCEP-ATP III modified for age was used to define metabolic syndrome. Results: The overall prevalence of metabolic syndrome was 2.6%. Prevalence of metabolic syndrome was higher in males (3.84% than in females (1.6% and slightly higher in urban area (2.80% than in rural area (2.52%, whereas prevalence of metabolic syndrome among centrally obese subjects was as high as 33.33%. High density lipoprotein cholesterol was the most common and high blood pressure was the least common constituent of metabolic syndrome. Metabolic syndrome was most prevalent in 16-18 years age group (4.79%. Conclusion : This study demonstrates that metabolic syndrome phenotype exists in substantial number (up to 3% of adolescent population in the Jammu region, India, and particularly 33% of obese adolescents are at risk to develop metabolic syndrome. These findings pose a serious threat to the current and future health of these young people.

Poincare covariance and κ-Minkowski spacetime

International Nuclear Information System (INIS)

Dabrowski, Ludwik; Piacitelli, Gherardo

2011-01-01

A fully Poincare covariant model is constructed as an extension of the κ-Minkowski spacetime. Covariance is implemented by a unitary representation of the Poincare group, and thus complies with the original Wigner approach to quantum symmetries. This provides yet another example (besides the DFR model), where Poincare covariance is realised a la Wigner in the presence of two characteristic dimensionful parameters: the light speed and the Planck length. In other words, a Doubly Special Relativity (DSR) framework may well be realised without deforming the meaning of 'Poincare covariance'. -- Highlights: → We construct a 4d model of noncommuting coordinates (quantum spacetime). → The coordinates are fully covariant under the undeformed Poincare group. → Covariance a la Wigner holds in presence of two dimensionful parameters. → Hence we are not forced to deform covariance (e.g. as quantum groups). → The underlying κ-Minkowski model is unphysical; covariantisation does not cure this.

Prevalence of eating disorders in middle-aged women.

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Mangweth-Matzek, Barbara; Hoek, Hans W; Rupp, Claudia I; Lackner-Seifert, Kerstin; Frey, Nadja; Whitworth, Alexandra B; Pope, Harrison G; Kinzl, Johann

2014-04-01

Little is known about the prevalence and correlates of eating disorders (ED) in middle-aged women. We mailed anonymous questionnaires to 1,500 Austrian women aged 40-60 years, assessing ED (defined by DSM-IV), subthreshold ED, body image, and quality of life. We broadly defined "subthreshold ED" by the presence of either (1) binge eating with loss of control or (2) purging behavior, without requiring any of the other usual DSM-IV criteria for frequency or severity of these symptoms. Of the 715 (48%) responders, 33 [4.6%; 95% confidence interval (CI): 3.3-6.4%] reported symptoms meeting full DSM-IV criteria for an ED [bulimia nervosa = 10; binge eating disorder = 11; eating disorder not otherwise specified (EDNOS) = 12]. None displayed anorexia nervosa. Another 34 women (4.8%; CI: 3.4-6.6%) displayed subthreshold ED. These women showed levels of associated psychopathology virtually equal to the women with full-syndrome diagnoses. ED appear common in middle-aged women, with a preponderance of binge eating disorder and EDNOS diagnoses as compared to the "classical" diagnoses of anorexia and bulimia nervosa. Interestingly, middle-aged women with even very broadly defined subthreshold ED showed distress and impairment comparable to women with full-scale ED. Copyright © 2013 Wiley Periodicals, Inc.

Prevalence of alcohol-interactive prescription medication use among current drinkers: United States, 1999 to 2010.

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Breslow, Rosalind A; Dong, Chuanhui; White, Aaron

2015-02-01

The majority of Americans consume alcoholic beverages. Alcohol interacts negatively with numerous commonly prescribed medications. Yet, on a population level, little is known about use of alcohol-interactive (AI) prescription medications among drinkers. The purpose of our study was to determine the prevalence of AI prescription medication use among current drinkers in the U.S. population. Data were from the National Health and Nutrition Examination Survey (NHANES 1999 to 2010); 26,657 adults aged ≥20 years had data on past year alcohol consumption and past month prescription medication use. Analyses were adjusted for covariates: age, race/ethnicity, education, marital status, and smoking. Statistical procedures accounted for survey stratification, clustering, and nonresponse. Analyses were weighted to be nationally representative. The unadjusted total prevalence of AI medication use was 42.8% (95% confidence interval [CI] 41.5 to 44.0). Among current drinkers, adjusted prevalence was 41.5% (CI 40.3 to 42.7). Among participants aged ≥65 total prevalence of AI medication use was 78.6% (CI 77.3 to 79.9) and adjusted prevalence among current drinkers was 77.8% (CI 75.7 to 79.7). The AI medications most commonly used by current drinkers were cardiovascular agents, central nervous system agents, and metabolic agents. Our results suggest that there could be substantial simultaneous exposure to alcohol and AI prescription medications in the U.S. population. Given the adverse health risks of combining alcohol with AI prescription medications, future efforts are needed to collect data to determine actual simultaneous prevalence. Copyright © 2015 by the Research Society on Alcoholism.

Comparison of prevalence of metabolic syndrome in hospital and community-based Japanese patients with schizophrenia

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Yamashita Hakuei

2011-09-01

Full Text Available Abstract Background Lifestyle factors, such as an unbalanced diet and lack of physical activity, may affect the prevalence of metabolic syndrome (MetS in schizophrenic patients. The aim of this study was to compare the MetS prevalence between inpatients and outpatients among schizophrenic population in Japan. Methods We recruited inpatients (n = 759 and outpatients (n = 427 with a Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV diagnosis of schizophrenia or schizoaffective disorder from 7 psychiatric hospitals using a cross-sectional design. MetS prevalence was assessed using three different definitions, including the adapted National Cholesterol Education Program Adult Treatment Panel (ATP III-A. Results The overall MetS prevalences based on the ATP III-A definition were 15.8% in inpatients and 48.1% in outpatients. In a logistic regression model with age and body mass index as covariates, being a schizophrenic outpatient, compared to being a schizophrenic inpatient, was a significant independent factor (odds ratio = 3.66 for males, 2.48 for females in the development of MetS under the ATP III-A definition. The difference in MetS prevalence between inpatients and outpatients was observed for all age groups in males and for females over 40 years of age. Conclusions Outpatients with schizophrenia or schizoaffective disorder in Japan had a high prevalence of MetS compared to inpatients. MetS in schizophrenic outpatients should be carefully monitored to minimize the risks. A change of lifestyle might improve MetS in schizophrenic patients.

Early grey matter changes in structural covariance networks in Huntington's disease.

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Coppen, Emma M; van der Grond, Jeroen; Hafkemeijer, Anne; Rombouts, Serge A R B; Roos, Raymund A C

2016-01-01

Progressive subcortical changes are known to occur in Huntington's disease (HD), a hereditary neurodegenerative disorder. Less is known about the occurrence and cohesion of whole brain grey matter changes in HD. We aimed to detect network integrity changes in grey matter structural covariance networks and examined relationships with clinical assessments. Structural magnetic resonance imaging data of premanifest HD ( n  = 30), HD patients (n = 30) and controls (n = 30) was used to identify ten structural covariance networks based on a novel technique using the co-variation of grey matter with independent component analysis in FSL. Group differences were studied controlling for age and gender. To explore whether our approach is effective in examining grey matter changes, regional voxel-based analysis was additionally performed. Premanifest HD and HD patients showed decreased network integrity in two networks compared to controls. One network included the caudate nucleus, precuneous and anterior cingulate cortex (in HD p  covariance might be a sensitive approach to reveal early grey matter changes, especially for premanifest HD.

Time from ACL injury to reconstruction and the prevalence of additional intra-articular pathology: is patient age an important factor?

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Magnussen, Robert A; Pedroza, Angela D; Donaldson, Christopher T; Flanigan, David C; Kaeding, Christopher C

2013-09-01

Meniscus and cartilage lesions have been reported to be prevalent during delayed reconstruction of anterior cruciate ligament (ACL) injuries. Relatively, little work has been done exploring the influence of patient age on this relationship. The purpose of this study is to determine whether the effect of time from ACL injury to reconstruction on the prevalence of associated meniscal and chondral injury is influenced by patient age. It was hypothesized that patients in whom the time from ACL injury to reconstruction exceeds 12 weeks will exhibit an increased prevalence of medial compartment pathology relative to those reconstructed within 12 weeks of injury in patients of all ages. Data detailing time from ACL injury to reconstruction and the prevalence of intra-articular findings were obtained in 311 of 489 consecutive patients undergoing primary isolated ACL reconstruction. Patients were divided into two groups based on whether the time from ACL injury to reconstruction was time from ACL injury to reconstruction exceeded 12 weeks. The prevalence of lateral meniscal injury did not increase with increasing time ACL injury to surgery. Among patients aged 22 years and under, there was no increase in the prevalence of intra-articular pathology in any compartment in the late reconstruction group. In contrast, among patients over the age of 22, there was a significant increase in the prevalence of medial chondral injury (p = 0.042) in the late reconstruction group. The prevalence of injuries to the meniscus and articular cartilage in the medial compartment of the knee is increased with increasing time from ACL injury to reconstruction. This relationship may vary depending on patient age. Patients over the age of 22 exhibit a higher prevalence of intra-articular injury with delayed reconstruction, while no such differences are noted among younger patients. Retrospective comparative study, level III.

Prevalence of degree of severity of temporomandibular joint disorder based on sex and age group

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Luciana Dewanti

2009-03-01

Full Text Available Temporomandibular joint disorders are disturbances of mastication system due to one or more component of mastication system does not properly function. The factors that play a role in this problem divided into three factors; a predisposition factor (systemic, occlusion disturbances and psychological trouble, b initiation factor (traumatic and c perpetuation factor (social behavior. These disorders are able to cause a variety of symptom suck as limitedness of jaw movement, clicking, deviation locked joint, muscle pain, joint pain, jaw movement pain and pain of ear and headache. The objective of this study was to obtain information about the prevalence degree of severity of the temporomandibular joint disorder, the differences of prevalence between man and woman and the different among age groups. The study was descriptive and analysis survey, done to 134 patients as an experimental sample of 3–75-year old that have visited Dental Hospital, Padjadjaran University Bandung, during February 2008. Sample consist of 57 men and 77 women were evaluated by using Helkimo Index and analysis by using Z statistical proportion test to know the existence of difference prevalence degree of severity between man and woman and using the chi-square test to know the difference prevalence among age groups.The result of this study shows that there is highly prevalence severity of temporomandibular joint disorder (84,33% and significantly different on prevalence severity between man and woman and among a group of ages.The conclusion can be drawn that patients who visited the dental hospital, Padjadjaran University have higher prevalence severity of temporomandibular joint disorder where a woman has higher level compare to man, and the young adult group has highest either man and woman. Clicking is the most often symptom appear to man and woman.

Prevalence of somatoform disorders and medically unexplained symptoms in old age populations in comparison with younger age groups : A systematic review

NARCIS (Netherlands)

Hilderink, P. H.; Collard, R.; Rosmalen, J. G. M.; Voshaar, R. C. Oude

Objective: To review current knowledge regarding the prevalence of somatization problems in later life by level of caseness (somatoform disorders and medically unexplained symptoms, MUS) and to compare these rates with those in middle-aged and younger age groups. Method: A systematic search of the

Modeling Covariance Breakdowns in Multivariate GARCH

OpenAIRE

Jin, Xin; Maheu, John M

2014-01-01

This paper proposes a flexible way of modeling dynamic heterogeneous covariance breakdowns in multivariate GARCH (MGARCH) models. During periods of normal market activity, volatility dynamics are governed by an MGARCH specification. A covariance breakdown is any significant temporary deviation of the conditional covariance matrix from its implied MGARCH dynamics. This is captured through a flexible stochastic component that allows for changes in the conditional variances, covariances and impl...

Prevalence of Shigella among diarrheic children under-5 years of age attending at Mekelle health center, north Ethiopia.

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Kahsay, Atsebaha Gebrekidan; Teklemariam, Zelalem

2015-12-15

Shigellosis is recognized as a major global public health problem especially in developing countries particularly in children under-5 years of age. Therefore; the objective of this study was to determine the prevalence of Shigella among diarrheic children under-5 years of age attending at Mekelle health center, north Ethiopia. A cross-sectional study was conducted among diarrheic children under-5 years of age from March to May, 2012. Structured questionnaire was used to collect the data. Study participants were recruited by convenience sampling technique. Shigella was isolated and identified using standard bacteriological techniques. A total of 241 study participants were included in the study. The overall prevalence of Shigella in this study was 13.3% (32/241). High prevalence of Shigella (22.6%) was revealed from the age group of 12-23 months. No Shigella was isolated from the age group of 0-5 months. Majority of the isolates of Shigella were from bloody and mucoid diarrhea. There was high prevalence of Shigella infection in this study. Children among the age group of 12-23 months were highly affected. Therefore; responsible bodies should work hard on preventive measures to reduce or eradicate the problem occurred due to shigellosis.

Prevalence, incidence, and age at diagnosis in Marfan Syndrome.

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Groth, Kristian A; Hove, Hanne; Kyhl, Kasper; Folkestad, Lars; Gaustadnes, Mette; Vejlstrup, Niels; Stochholm, Kirstine; Østergaard, John R; Andersen, Niels H; Gravholt, Claus H

2015-12-02

Marfan syndrome is a genetic disorder with considerable morbidity and mortality. Presently, clinicians use the 2010 revised Ghent nosology, which includes optional genetic sequencing of the FBN1 gene, to diagnose patients. So far, only a few studies based on older diagnostic criteria have reported a wide range of prevalence and incidence. Our aim was to study prevalence, incidence, and age at diagnosis in patients with Marfan syndrome. Using unique Danish patient-registries, we identified all possible Marfan syndrome patients recorded by the Danish healthcare system (1977-2014). Following, we confirmed or rejected the diagnosis according to the 2010 revised Ghent nosology. We identified a total of 1628 persons with possible Marfan syndrome. We confirmed the diagnosis in 412, whereof 46 were deceased, yielding a maximum prevalence of 6.5/100,000 at the end of 2014. The annual median incidence was 0.19/100,000 (range: 0.0-0.7) which increased significantly with an incidence rate ratio of 1.03 (95% CI: 1.02-1.04, p Marfan syndrome during the study period is possibly due to build-up of a registry. Since early diagnosis is essential in preventing aortic events, diagnosing Marfan syndrome remains a task for both pediatricians and physicians caring for adults.

Econometric analysis of realised covariation: high frequency covariance, regression and correlation in financial economics

OpenAIRE

Ole E. Barndorff-Nielsen; Neil Shephard

2002-01-01

This paper analyses multivariate high frequency financial data using realised covariation. We provide a new asymptotic distribution theory for standard methods such as regression, correlation analysis and covariance. It will be based on a fixed interval of time (e.g. a day or week), allowing the number of high frequency returns during this period to go to infinity. Our analysis allows us to study how high frequency correlations, regressions and covariances change through time. In particular w...

Covariance Based Pre-Filters and Screening Criteria for Conjunction Analysis

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George, E., Chan, K.

2012-09-01

Several relationships are developed relating object size, initial covariance and range at closest approach to probability of collision. These relationships address the following questions: - Given the objects' initial covariance and combined hard body size, what is the maximum possible value of the probability of collision (Pc)? - Given the objects' initial covariance, what is the maximum combined hard body radius for which the probability of collision does not exceed the tolerance limit? - Given the objects' initial covariance and the combined hard body radius, what is the minimum miss distance for which the probability of collision does not exceed the tolerance limit? - Given the objects' initial covariance and the miss distance, what is the maximum combined hard body radius for which the probability of collision does not exceed the tolerance limit? The first relationship above allows the elimination of object pairs from conjunction analysis (CA) on the basis of the initial covariance and hard-body sizes of the objects. The application of this pre-filter to present day catalogs with estimated covariance results in the elimination of approximately 35% of object pairs as unable to ever conjunct with a probability of collision exceeding 1x10-6. Because Pc is directly proportional to object size and inversely proportional to covariance size, this pre-filter will have a significantly larger impact on future catalogs, which are expected to contain a much larger fraction of small debris tracked only by a limited subset of available sensors. This relationship also provides a mathematically rigorous basis for eliminating objects from analysis entirely based on element set age or quality - a practice commonly done by rough rules of thumb today. Further, these relations can be used to determine the required geometric screening radius for all objects. This analysis reveals the screening volumes for small objects are much larger than needed, while the screening volumes for

Influence of age, mode of delivery and parity on the prevalence of posterior pelvic floor dysfunctions

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Sthela Maria Murad-Regadas

2011-12-01

Full Text Available CONTEXT: The correlation between vaginal delivery, age and pelvic floor dysfunctions involving obstructed defecation is still a matter of controversy. OBJECTIVES: To determine the influence of age, mode of delivery and parity on the prevalence of posterior pelvic floor dysfunctions in women with obstructed defecation syndrome. METHODS: Four hundred sixty-nine females with obstructed defecation syndrome were retrospectively evaluated using dynamic 3D ultrasonography to quantify posterior pelvic floor dysfunctions (rectocele grade II or III, rectal intussusception, paradoxical contraction/non-relaxation of the puborectalis and entero/ sigmoidocele grade III. In addition, sphincter damage was evaluated. Patients were grouped according to age (50y and stratified by mode of delivery and parity: group I (50y: 251 patients, 60 nulliparous, 148 vaginal delivery and 43 only caesarean section. Additionally, patients were stratified by number of vaginal deliveries: 0 - nulliparous (n = 135, 1 - vaginal (n = 46, >1 - vaginal (n = 166. RESULTS: Rectocele grade II or III, intussusception, rectocele + intussusception and sphincter damage were more prevalent in Group II (P = 0.0432; P = 0.0028; P = 0.0178; P = 0.0001. The stratified groups (nulliparous, vaginal delivery and cesarean did not differ significantly with regard to rectocele, intussusception or anismus in each age group. Entero/sigmoidocele was more prevalent in the vaginal group 50y. No correlation was found between rectocele and the number of vaginal deliveries. CONCLUSION: Higher age (>50 years was shown to influence the prevalence of significant rectocele, intussusception and sphincter damage in women. However, delivery mode and parity were not correlated with the prevalence of rectocele, intussusception and anismus in women with obstructed defecation.

Prevalence of Successful Aging in the Elderly in Western Mexico

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Elva Dolores Arias-Merino

2012-01-01

Full Text Available Objectives. The aim of this paper is to estimate the prevalence of successful aging in the elderly in Western Mexico and to analyze its variability by age, sex, education, marital status, and pension. Methods. This study employs data from the Health, Wellbeing, and Aging Study (SABE in Jalisco and Colima, Mexico. Successful aging was operationalized in accordance with no important disease, no disability, physical functioning, cognitive functioning, and being actively. There were a total of 3116 elderly. Results. 12.6% of older adults were “successful” aging. The old-old is a lower proportion of successful aging people; it ranges from 18.9% among people aged 60–69 years to 3.9% in the 80–89 years and up to 1% in people 90 and older. There were also differences according to sex (P=.000, with a higher proportion of successful aging men (18.4% compared with 9.2% of women. There were differences in educational level (P=.000; those higher with education were found to be more successful aging, and also there were differences in marital status for married people (P=.000. Discussion. A small number of older adults meet the criteria definition of successful aging, suggesting the need to analyze in depth the concept and the indicators.

ISSUES IN NEUTRON CROSS SECTION COVARIANCES

Energy Technology Data Exchange (ETDEWEB)

Mattoon, C.M.; Oblozinsky,P.

2010-04-30

We review neutron cross section covariances in both the resonance and fast neutron regions with the goal to identify existing issues in evaluation methods and their impact on covariances. We also outline ideas for suitable covariance quality assurance procedures.We show that the topic of covariance data remains controversial, the evaluation methodologies are not fully established and covariances produced by different approaches have unacceptable spread. The main controversy is in very low uncertainties generated by rigorous evaluation methods and much larger uncertainties based on simple estimates from experimental data. Since the evaluators tend to trust the former, while the users tend to trust the latter, this controversy has considerable practical implications. Dedicated effort is needed to arrive at covariance evaluation methods that would resolve this issue and produce results accepted internationally both by evaluators and users.

Spatial prediction of malaria prevalence in an endemic area of Bangladesh

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Islam Akramul

2010-05-01

Full Text Available Abstract Background Malaria is a major public health burden in Southeastern Bangladesh, particularly in the Chittagong Hill Tracts region. Malaria is endemic in 13 districts of Bangladesh and the highest prevalence occurs in Khagrachari (15.47%. Methods A risk map was developed and geographic risk factors identified using a Bayesian approach. The Bayesian geostatistical model was developed from previously identified individual and environmental covariates (p Results Predicted high prevalence areas were located along the north-eastern areas, and central part of the study area. Low to moderate prevalence areas were predicted in the southwestern, southeastern and central regions. Individual age and nearness to fragmented forest were associated with malaria prevalence after adjusting the spatial auto-correlation. Conclusion A Bayesian analytical approach using multiple enabling technologies (geographic information systems, global positioning systems, and remote sensing provide a strategy to characterize spatial heterogeneity in malaria risk at a fine scale. Even in the most hyper endemic region of Bangladesh there is substantial spatial heterogeneity in risk. Areas that are predicted to be at high risk, based on the environment but that have not been reached by surveys are identified.

Prevalence of spinal disorders and their relationships with age and gender

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Alshami, Ali M.

2015-01-01

Objectives: To establish the period prevalence of spinal disorders referred to physical therapy in a university hospital over a 3-year period, and to determine the relationships of common spinal disorders with patients’ age and gender. Methods: This retrospective study was conducted in the Physical Therapy Department, King Fahd Hospital of the University, Dammam, Saudi Arabia. Computer data of all new electronic referrals from January 2011 to December 2013 were retrieved and reviewed. The computer data included demographic information, referring facility, and diagnosis/disorder. Results: One thousand six hundred and sixty-nine (28.1%) of all referred patients (5929) had spinal disorders. The most common disorders affected the lumbar spine (53.1%) and cervical spine (27.1%), and pain was the most common disorder. Neck pain (60.5%) was more common in patients spondylosis was common (~30%) in the >30 age groups. Spondylosis and low back pain were more prevalent in women (7.8% and 76.2%) than in men (73.9% and 3.3%). Conclusion: Spinal disorders were common compared with other disorders. Low back pain and neck pain were the most common spinal disorders. Age and gender were weakly related to some of the disorders that affected the lumbar and cervical spine. PMID:25987116

Prevalence of age-related macular degeneration in Nakuru, Kenya: a cross-sectional population-based study.

Directory of Open Access Journals (Sweden)

Wanjiku Mathenge

Full Text Available Diseases of the posterior segment of the eye, including age-related macular degeneration (AMD, have recently been recognised as the leading or second leading cause of blindness in several African countries. However, prevalence of AMD alone has not been assessed. We hypothesized that AMD is an important cause of visual impairment among elderly people in Nakuru, Kenya, and therefore sought to assess the prevalence and predictors of AMD in a diverse adult Kenyan population.In a population-based cross-sectional survey in the Nakuru District of Kenya, 100 clusters of 50 people 50 y of age or older were selected by probability-proportional-to-size sampling between 26 January 2007 and 11 November 2008. Households within clusters were selected through compact segment sampling. All participants underwent a standardised interview and comprehensive eye examination, including dilated slit lamp examination by an ophthalmologist and digital retinal photography. Images were graded for the presence and severity of AMD lesions following a modified version of the International Classification and Grading System for Age-Related Maculopathy. Comparison was made between slit lamp biomicroscopy (SLB and photographic grading. Of 4,381 participants, fundus photographs were gradable for 3,304 persons (75.4%, and SLB was completed for 4,312 (98%. Early and late AMD prevalence were 11.2% and 1.2%, respectively, among participants graded on images. Prevalence of AMD by SLB was 6.7% and 0.7% for early and late AMD, respectively. SLB underdiagnosed AMD relative to photographic grading by a factor of 1.7. After controlling for age, women had a higher prevalence of early AMD than men (odds ratio 1.5; 95% CI, 1.2-1.9. Overall prevalence rose significantly with each decade of age. We estimate that, in Kenya, 283,900 to 362,800 people 50 y and older have early AMD and 25,200 to 50,500 have late AMD, based on population estimates in 2007.AMD is an important cause of visual

Prevalence and risk factors of obesity among school-aged children in Xi'an, China.

Science.gov (United States)

Yi, Xiaoqing; Yin, Chunyan; Chang, Ming; Xiao, Yanfeng

2012-02-01

The purpose of this study was to examine the prevalence and the risk factors associated with obesity among school-aged children in Xi'an city. The body mass index of 6,740 children aged 7-18 years was compared with the Working Group on Obesity in China cut-off value to estimate the prevalence of obesity. A case-control study of obese and non-obese children was carried out to study risk factors for obesity. A standardized questionnaire was used to collect information on possible risk factors causing obesity. Univariate analysis was performed first to compare the distribution of risk factors between cases and controls. Conditional logistic regression analysis was used to assess independent risk factors of obesity. The results showed that the overall prevalence of obesity among school-aged children was 4.11% (4.63% for males and 3.57% for females). A total of 516 subjects (258 pairs of cases and controls) were included in the final analysis. High maternal education and a longer sleeping time were shown to be protective factors against obesity (odds ratio [OR] 0.148, 95% confidence interval [CI] 0.074-0.296 and OR 0.472, 95% CI 0.342-0.652, respectively). Whereas family history of diabetes (OR 5.498, 95% CI 2.606-11.600), parental overweight (OR 3.720, 95% CI 2.068-6.689), and watching television, playing video games, and using computers (OR 1.564, 95% CI 1.133-2.159) were associated with a higher obesity risk. The prevalence of childhood obesity in Xi'an has become a concern, and sleeping time, sedentary behavior, and family factors have pronounced effects on the prevalence of obesity.

Networks of myelin covariance

Science.gov (United States)

Slater, David; Ruef, Anne; Sanabria‐Diaz, Gretel; Preisig, Martin; Kherif, Ferath; Draganski, Bogdan; Lutti, Antoine

2017-01-01

Abstract Networks of anatomical covariance have been widely used to study connectivity patterns in both normal and pathological brains based on the concurrent changes of morphometric measures (i.e., cortical thickness) between brain structures across subjects (Evans, 2013). However, the existence of networks of microstructural changes within brain tissue has been largely unexplored so far. In this article, we studied in vivo the concurrent myelination processes among brain anatomical structures that gathered together emerge to form nonrandom networks. We name these “networks of myelin covariance” (Myelin‐Nets). The Myelin‐Nets were built from quantitative Magnetization Transfer data—an in‐vivo magnetic resonance imaging (MRI) marker of myelin content. The synchronicity of the variations in myelin content between anatomical regions was measured by computing the Pearson's correlation coefficient. We were especially interested in elucidating the effect of age on the topological organization of the Myelin‐Nets. We therefore selected two age groups: Young‐Age (20–31 years old) and Old‐Age (60–71 years old) and a pool of participants from 48 to 87 years old for a Myelin‐Nets aging trajectory study. We found that the topological organization of the Myelin‐Nets is strongly shaped by aging processes. The global myelin correlation strength, between homologous regions and locally in different brain lobes, showed a significant dependence on age. Interestingly, we also showed that the aging process modulates the resilience of the Myelin‐Nets to damage of principal network structures. In summary, this work sheds light on the organizational principles driving myelination and myelin degeneration in brain gray matter and how such patterns are modulated by aging. PMID:29271053

The prevalence of type 1 diabetes mellitus among 15-34-year-aged Lithuanian inhabitants during 1991-2010.

Science.gov (United States)

Ostrauskas, Rytas

2015-04-01

To summarize the data on the prevalence of type 1 diabetes mellitus among 15-34-year-aged Lithuania inhabitants (1991-2010). New prevalent cases consist of growing-up patients with diabetes onset in childhood, i.e., up to 14 years, new onset 15-34-year-aged type 1 diabetic patients Lithuanian inhabitants, and immigrants. The data on type 1 diabetes was collected with the help of general practitioners and regional endocrinologists in Lithuania. On 31 December 1991, there were 1202 adolescent and adult 15-34-year-aged patients with type 1 diabetes mellitus or 103.59 per 100,000 inhabitants of the same age group (95% Poisson CI 97.90-109.62), and at the end of 2010 - 1533 or 187.80 (178.63-197.44), respectively in Lithuania. During 19-year period the mean increase of type 1 diabetic patients was 1.25±1.94% per year or 1.47±2.74 per 100,000 inhabitants per mean year of the study period (for males 1.42±2.14% or 1.69±3.05/100,000 and for females 1.05±1.99%, or 1.24±2.92/100,000). Regression-based linear trends showed that the prevalence of type 1 diabetes mellitus in 15-34-year-age group had a tendency to increase among males (r=0.953; p1) and females (r=0.970; p1). The age adjusted prevalence frequencies for males and females in 1991 were correspondingly 102.81/100,000 and 104.55/100,000, and in 2010 - 193.75 and 182.01. The prevalence of type 1 diabetes mellitus among 15-34-year-age males and females had a tendency to increase during 1991-2010. Copyright © 2014 Primary Care Diabetes Europe. Published by Elsevier Ltd. All rights reserved.

Covariance Partition Priors: A Bayesian Approach to Simultaneous Covariance Estimation for Longitudinal Data.

Science.gov (United States)

Gaskins, J T; Daniels, M J

2016-01-02

The estimation of the covariance matrix is a key concern in the analysis of longitudinal data. When data consists of multiple groups, it is often assumed the covariance matrices are either equal across groups or are completely distinct. We seek methodology to allow borrowing of strength across potentially similar groups to improve estimation. To that end, we introduce a covariance partition prior which proposes a partition of the groups at each measurement time. Groups in the same set of the partition share dependence parameters for the distribution of the current measurement given the preceding ones, and the sequence of partitions is modeled as a Markov chain to encourage similar structure at nearby measurement times. This approach additionally encourages a lower-dimensional structure of the covariance matrices by shrinking the parameters of the Cholesky decomposition toward zero. We demonstrate the performance of our model through two simulation studies and the analysis of data from a depression study. This article includes Supplementary Material available online.

[Rate of prevalence, awareness, treatment and control of hypertension among women at reproductive age in China in 2013].

Science.gov (United States)

Wang, Z Q; Zhao, Y F; Yang, J; Wang, L M; Zhao, Z P; Zeng, X Y; Wang, L H

2017-12-06

Objective: To analyze the rate of prevalence, awareness, treatment and control of hypertension among women at reproductive age (18-49 years old) in China in 2013. Methods: The analysis used data obtained from the China Chronic and non-communicable disease surveillance in 2013.The surveillance included 176 534 adults aging ≥18 years old, who were selected from 302 surveillance points by multi-stage cluster random sampling method. A total of 46 674 women at reproductive age (18-49 years old) were investigated. Blood pressures were measured by electronic blood pressure monitor. After being weighted according to complex sampling scheme and post-stratification, the rate of prevalence, awareness, treatment and control of hypertension were compared by different characteristics such as age, education, urban and rural areas, and geographic locations. Results: The prevalence of hypertension among women at reproductive age (18-49 years old) in China in 2013 was 13.5%. The rate in the rural areas was higher than that in urban areas (χ(2)=46.23, P 0.05). The hypertension prevalence in all age groups (18-24, 25-29, 30-34, 35-39, 40-44, 45-49 years old) were 6.6%, 9.2%, 9.6%, 12.0%, 17.9% and 28.3%, respectively. The prevalence of hypertension showed a rising trend with age increasing ( t= 12.32, Pareas; and 21.3%, 18.5% and 5.9%, respectively in rural areas. The rates in urban areas were all higher than those in rural areas (chi square were separately 18.98, 21.31, and 6.80, P values areas.

Covariant diagrams for one-loop matching

Energy Technology Data Exchange (ETDEWEB)

Zhang, Zhengkang [Michigan Center for Theoretical Physics (MCTP), University of Michigan,450 Church Street, Ann Arbor, MI 48109 (United States); Deutsches Elektronen-Synchrotron (DESY),Notkestraße 85, 22607 Hamburg (Germany)

2017-05-30

We present a diagrammatic formulation of recently-revived covariant functional approaches to one-loop matching from an ultraviolet (UV) theory to a low-energy effective field theory. Various terms following from a covariant derivative expansion (CDE) are represented by diagrams which, unlike conventional Feynman diagrams, involve gauge-covariant quantities and are thus dubbed “covariant diagrams.” The use of covariant diagrams helps organize and simplify one-loop matching calculations, which we illustrate with examples. Of particular interest is the derivation of UV model-independent universal results, which reduce matching calculations of specific UV models to applications of master formulas. We show how such derivation can be done in a more concise manner than the previous literature, and discuss how additional structures that are not directly captured by existing universal results, including mixed heavy-light loops, open covariant derivatives, and mixed statistics, can be easily accounted for.

Covariant diagrams for one-loop matching

International Nuclear Information System (INIS)

Zhang, Zhengkang

2017-01-01

We present a diagrammatic formulation of recently-revived covariant functional approaches to one-loop matching from an ultraviolet (UV) theory to a low-energy effective field theory. Various terms following from a covariant derivative expansion (CDE) are represented by diagrams which, unlike conventional Feynman diagrams, involve gauge-covariant quantities and are thus dubbed “covariant diagrams.” The use of covariant diagrams helps organize and simplify one-loop matching calculations, which we illustrate with examples. Of particular interest is the derivation of UV model-independent universal results, which reduce matching calculations of specific UV models to applications of master formulas. We show how such derivation can be done in a more concise manner than the previous literature, and discuss how additional structures that are not directly captured by existing universal results, including mixed heavy-light loops, open covariant derivatives, and mixed statistics, can be easily accounted for.

Age trends in the prevalence of cervical squamous intraepithelial lesions among HIV-positive women in Cameroon: a cross-sectional study

LENUS (Irish Health Repository)

Atashili, Julius

2012-10-29

AbstractBackgroundCervical squamous intra-epithelial lesions (SIL) are more frequent in HIV-positive women overall. However the appropriate age at which to begin and end cervical cancer screening for early detection of lesions in HIV-positive women is not clear. We assessed the age-specific prevalence of any SIL and SIL requiring colposcopy in HIV-positive women in Cameroon.MethodsWe enrolled, interviewed and conducted conventional cervical cytology in 282 women, aged 19--68 years, initiating antiretroviral therapy in three clinics in Cameroon. In bivariable analyses, the crude relationship between age and the presence of lesions was assessed using locally weighted regression (LOWESS) methods. In multivariate analyses, generalized linear models with prevalence as the outcome, an identity link and a binomial distribution, were used to estimate prevalence differences. Bias analyses were conducted to assess the potential effect of inaccuracies in cytology.ResultsSIL were detected in 43.5% of the 276 women with satisfactory samples, 17.8% of whom had ASC-H\\/HSIL. On average, women aged 26 to 59 tended to have a slightly higher prevalence of any SIL than other women (Prevalence difference PD: 6.5%; 95%CI: -11.4, 24.4%). This PD was a function of CD4 count (heterogeneity test p-value =0.09): amongst patients with CD4 counts less than 200cells\\/uL, the prevalence was higher in patients aged 26--59, while there was essentially no difference amongst women with CD4 counts greater than 200 cells\\/uL. ASC-H\\/HSIL were present in women as young as 19 and as old as 62. Overall the prevalence of ASC-H\\/HSIL increased by 0.7% (95%CI: -3.8%, 5.1%) per decade increase in age.ConclusionBoth severe and less severe lesions were prevalent at all ages suggesting little utility of age-targeted screening among HIV-positive women. Nevertheless, the long-term evolution of these lesions needs to be assessed in prospective studies.

Fast Computing for Distance Covariance

OpenAIRE

Huo, Xiaoming; Szekely, Gabor J.

2014-01-01

Distance covariance and distance correlation have been widely adopted in measuring dependence of a pair of random variables or random vectors. If the computation of distance covariance and distance correlation is implemented directly accordingly to its definition then its computational complexity is O($n^2$) which is a disadvantage compared to other faster methods. In this paper we show that the computation of distance covariance and distance correlation of real valued random variables can be...

On estimating cosmology-dependent covariance matrices

International Nuclear Information System (INIS)

Morrison, Christopher B.; Schneider, Michael D.

2013-01-01

We describe a statistical model to estimate the covariance matrix of matter tracer two-point correlation functions with cosmological simulations. Assuming a fixed number of cosmological simulation runs, we describe how to build a 'statistical emulator' of the two-point function covariance over a specified range of input cosmological parameters. Because the simulation runs with different cosmological models help to constrain the form of the covariance, we predict that the cosmology-dependent covariance may be estimated with a comparable number of simulations as would be needed to estimate the covariance for fixed cosmology. Our framework is a necessary first step in planning a simulations campaign for analyzing the next generation of cosmological surveys

Age-specific and sex-specific prevalence of cerebral β-amyloidosis, tauopathy, and neurodegeneration in cognitively unimpaired individuals aged 50-95 years: a cross-sectional study.

Science.gov (United States)

Jack, Clifford R; Wiste, Heather J; Weigand, Stephen D; Therneau, Terry M; Knopman, David S; Lowe, Val; Vemuri, Prashanthi; Mielke, Michelle M; Roberts, Rosebud O; Machulda, Mary M; Senjem, Matthew L; Gunter, Jeffrey L; Rocca, Walter A; Petersen, Ronald C

2017-06-01

A new classification for biomarkers in Alzheimer's disease and cognitive ageing research is based on grouping the markers into three categories: amyloid deposition (A), tauopathy (T), and neurodegeneration or neuronal injury (N). Dichotomising these biomarkers as normal or abnormal results in eight possible profiles. We determined the clinical characteristics and prevalence of each ATN profile in cognitively unimpaired individuals aged 50 years and older. All participants were in the Mayo Clinic Study of Aging, a population-based study that uses a medical records linkage system to enumerate all individuals aged 50-89 years in Olmsted County, MN, USA. Potential participants are randomly selected, stratified by age and sex, and invited to participate in cognitive assessments; individuals without medical contraindications are invited to participate in brain imaging studies. Participants who were judged clinically as having no cognitive impairment and underwent multimodality imaging between Oct 11, 2006, and Oct 5, 2016, were included in the current study. Participants were classified as having normal (A-) or abnormal (A+) amyloid using amyloid PET, normal (T-) or abnormal (T+) tau using tau PET, and normal (N-) or abnormal (N+) neurodegeneration or neuronal injury using cortical thickness assessed by MRI. We used the cutoff points of standard uptake value ratio (SUVR) 1·42 (centiloid 19) for amyloid PET, 1·23 SUVR for tau PET, and 2·67 mm for MRI cortical thickness. Age-specific and sex-specific prevalences of the eight groups were determined using multinomial models combining data from 435 individuals with amyloid PET, tau PET, and MRI assessments, and 1113 individuals who underwent amyloid PET and MRI, but not tau PET imaging. The numbers of participants in each profile group were 165 A-T-N-, 35 A-T+N-, 63 A-T-N+, 19 A-T+N+, 44 A+T-N-, 25 A+T+N-, 35 A+T-N+, and 49 A+T+N+. Age differed by ATN group (pgroup (p=0·04), with carriers roughly twice as frequent in each

Prevalence of Candida spp. among healthy denture and nondenture wearers with respect to hygiene and age

Directory of Open Access Journals (Sweden)

Bharathi Prakash

2015-01-01

Full Text Available Dentures are inert and nonshading surfaces and therefore get easily colonized by Candida species. Subsequent biofilm produced by them lead to denture stomatitis and candidiasis. This study was aimed to understand the prevalence of Candida species among healthy denture and nondenture wearers with respect to their age and hygiene status. Swabs were collected from 50 complete dentures and 50 non-denture wearers and processed on Sabouraud′s dextrose agar. Identification of Candida species was done by staining and a battery of biochemical tests. Data obtained was correlated with age & oral hygiene and statistical analysis was performed. Candida was isolated from both denture and nondenture wearers. Prevalence of different Candida species was significantly higher in denture wearers and found predominated by C. albicans, C. tropicalis, C. dubliensis and C. glabrata. Among nondenture wearers, C. albicans and C. tropicalis were isolated. Prevalence of Candida increased with increasing age among denture wearers. Men presented declining denture hygiene compared to women with increasing age. In comparison to nondenture wearers, multispecies of Candida colonized the dentures thus presenting higher risk of candidiasis especially with increasing age.

ERRORJ. Covariance processing code. Version 2.2

International Nuclear Information System (INIS)

Chiba, Go

2004-07-01

ERRORJ is the covariance processing code that can produce covariance data of multi-group cross sections, which are essential for uncertainty analyses of nuclear parameters, such as neutron multiplication factor. The ERRORJ code can process the covariance data of cross sections including resonance parameters, angular and energy distributions of secondary neutrons. Those covariance data cannot be processed by the other covariance processing codes. ERRORJ has been modified and the version 2.2 has been developed. This document describes the modifications and how to use. The main topics of the modifications are as follows. Non-diagonal elements of covariance matrices are calculated in the resonance energy region. Option for high-speed calculation is implemented. Perturbation amount is optimized in a sensitivity calculation. Effect of the resonance self-shielding on covariance of multi-group cross section can be considered. It is possible to read a compact covariance format proposed by N.M. Larson. (author)

Characteristics of Adults with Down Syndrome: prevalence of age-related conditions

Directory of Open Access Journals (Sweden)

Angelo eCarfì

2014-12-01

Full Text Available Introduction. In the last decades, life expectancy of persons with Down syndrome (DS has dramatically increased and it is estimated that they will be living as long as the general population within a generation. Despite being included among the progeroid syndromes, because of the presence of features typically observed in older adults, DS is still regarded as a disease of pediatric interest. Because limited knowledge is available on the clinical characteristics of adults with DS, this study aimed to assess clinical and non-clinical features of this population and to describe similarities to the geriatric population. Methods. In this study, we described 60 adults with DS evaluated at the Day Hospital of the Geriatric Department of the Policlinico A. Gemelli, Università Cattolica del Sacro Cuore in Rome. Individuals were assessed through a standardized protocol. Results. The mean age of study participants was 38 years (range, 18 to 58 years and 42 (70.0% were women. Geriatric conditions were highly prevalent: severe cognitive impairment was diagnosed in 39 (65.0% participants, behavioral symptoms were present in 25 (41.7% and functional impairment in 23 (38.3%. Six (10.0% participants lived in institutions and 11 (18.3% were diagnosed as obese. The mean number of drugs used was 2.4; use of psychotropic drugs was highly prevalent. The most common chronic diseases were thyroid problems (44, 73.3%, followed by mood disorders (19, 31.7%, osteoporosis (18, 30.0% and cardiac problems (10, 16.7%. Geriatric conditions and chronic diseases were more prevalent among participants aged ≥40 years. Conclusions. Several similarities between older adults and adults with DS were observed. Comorbidities, geriatric conditions, cognitive and functional deficits and social problems are highly prevalent in both populations, contributing to the high complexity of these patients’ assessment and treatment.

Influence of age, mode of delivery and parity on the prevalence of posterior pelvic floor dysfunctions.

Science.gov (United States)

Murad-Regadas, Sthela Maria; Regadas, Francisco Sergio P; Rodrigues, Lusmar Veras; Furtado, Débora Couto; Gondim, Ana Cecília; Dealcanfreitas, Iris Daiana

2011-01-01

The correlation between vaginal delivery, age and pelvic floor dysfunctions involving obstructed defecation is still a matter of controversy. To determine the influence of age, mode of delivery and parity on the prevalence of posterior pelvic floor dysfunctions in women with obstructed defecation syndrome. Four hundred sixty-nine females with obstructed defecation syndrome were retrospectively evaluated using dynamic 3D ultrasonography to quantify posterior pelvic floor dysfunctions (rectocele grade II or III, rectal intussusception, paradoxical contraction/non-relaxation of the puborectalis and entero/ sigmoidocele grade III). In addition, sphincter damage was evaluated. Patients were grouped according to age (≤50y x >50y) and stratified by mode of delivery and parity: group I (≤50y): 218 patients, 75 nulliparous, 64 vaginal delivery and 79 only cesarean section and group II (>50y): 251 patients, 60 nulliparous, 148 vaginal delivery and 43 only caesarean section. Additionally, patients were stratified by number of vaginal deliveries: 0 - nulliparous (n = 135), 1 - vaginal (n = 46), >1 - vaginal (n = 166). Rectocele grade II or III, intussusception, rectocele + intussusception and sphincter damage were more prevalent in Group II (P = 0.0432; P = 0.0028; P = 0.0178; P = 0.0001). The stratified groups (nulliparous, vaginal delivery and cesarean) did not differ significantly with regard to rectocele, intussusception or anismus in each age group. Entero/sigmoidocele was more prevalent in the vaginal group 50y. No correlation was found between rectocele and the number of vaginal deliveries. Higher age (>50 years) was shown to influence the prevalence of significant rectocele, intussusception and sphincter damage in women. However, delivery mode and parity were not correlated with the prevalence of rectocele, intussusception and anismus in women with obstructed defecation.

Behavioral Risk Factor Surveillance System (BRFSS) Age-Adjusted Prevalence Data (2011 to present)

Data.gov (United States)

U.S. Department of Health & Human Services — 2011 to present. BRFSS combined land line and cell phone age-adjusted prevalence data. The BRFSS is a continuous, state-based surveillance system that collects...

Do executive functions explain the covariance between internalizing and externalizing behaviors?

Science.gov (United States)

Hatoum, Alexander S; Rhee, Soo Hyun; Corley, Robin P; Hewitt, John K; Friedman, Naomi P

2017-11-16

This study examined whether executive functions (EFs) might be common features of internalizing and externalizing behavior problems across development. We examined relations between three EF latent variables (a common EF factor and factors specific to updating working memory and shifting sets), constructed from nine laboratory tasks administered at age 17, to latent growth intercept (capturing stability) and slope (capturing change) factors of teacher- and parent-reported internalizing and externalizing behaviors in 885 individual twins aged 7 to 16 years. We then estimated the proportion of intercept-intercept and slope-slope correlations predicted by EF as well as the association between EFs and a common psychopathology factor (P factor) estimated from all 9 years of internalizing and externalizing measures. Common EF was negatively associated with the intercepts of teacher-rated internalizing and externalizing behavior in males, and explained 32% of their covariance; in the P factor model, common EF was associated with the P factor in males. Shifting-specific was positively associated with the externalizing slope across sex. EFs did not explain covariation between parent-rated behaviors. These results suggest that EFs are associated with stable problem behavior variation, explain small proportions of covariance, and are a risk factor that that may depend on gender.

Vertebral fracture prevalence among Greek healthy middle-aged postmenopausal women: association with demographics, anthropometric parameters, and bone mineral density.

Science.gov (United States)

Lambrinoudaki, Irene; Flokatoula, Maria; Armeni, Eleni; Pliatsika, Paraskevi; Augoulea, Areti; Antoniou, Aris; Alexandrou, Andreas; Creatsa, Maria; Panoulis, Constantinos; Dendrinos, Spyridon; Papacharalambous, Xenofon

2015-01-01

The prevalence of skeletal fractures shows a marked geographic variability; however, data regarding the Greek population remain limited. To evaluate the frequency of asymptomatic vertebral fractures (VFs), and potential risk factors, in a large sample of Greek postmenopausal women. A cross-sectional study at the University Menopause Clinic. Four hundred fifty-four postmenopausal women aged 35 to 80 years, with an average menopausal age of 9.2±7.1 years. They included medical history, anthropometric and biochemical parameters, bone mineral density (BMD) at lumbar spine (LS) and femoral neck (FN), and LS lateral radiographs. Lumbar spine lateral radiographs were evaluated according to quantitative procedures, aiming to identify VFs. Anthropometric and biochemical parameters and values of BMD were compared according to the presence of VFs. A total of 37 (8.15%) women had at least one VF. Lumbar spine and FN-osteoporosis was identified in up to 23.1% and 40.9% subjects with prevalent VFs, respectively. The prevalence of VFs was largely associated with age, with women aged 60 years or more presenting an up to fourfold risk compared with younger women. Moreover, the presence of VFs was associated with higher menopausal age, advanced age at menarche, a history of early menopause, and prolonged lactation. Lower LS-BMD and, especially, FN-BMD were negatively associated with VF prevalence (prevalent VF vs. no VF: LS-BMD, 0.89±0.16 g/cm(2) vs. 0.98±0.16 g/cm(2), p=.010; FN-BMD, 0.72±0.10 g/cm(2) vs. 0.81±0.12 g/cm(2), p=.008). Asymptomatic VFs are common among Greek healthy middle-aged postmenopausal women. More than 50% subjects with prevalent VFs present with normal BMD or osteopenia. Age and bone density classification at the FN presented the strongest association with the prevalence of VFs. Copyright © 2015 Elsevier Inc. All rights reserved.

Covariance matrix estimation for stationary time series

OpenAIRE

Xiao, Han; Wu, Wei Biao

2011-01-01

We obtain a sharp convergence rate for banded covariance matrix estimates of stationary processes. A precise order of magnitude is derived for spectral radius of sample covariance matrices. We also consider a thresholded covariance matrix estimator that can better characterize sparsity if the true covariance matrix is sparse. As our main tool, we implement Toeplitz [Math. Ann. 70 (1911) 351–376] idea and relate eigenvalues of covariance matrices to the spectral densities or Fourier transforms...

Structural and functional connectivity underlying grey matter covariance: impact of developmental insult.

Science.gov (United States)

Paquola, Casey; Bennett, Maxwell; Lagopoulos, Jim

2018-05-15

Structural covariance networks (SCNs) may offer unique insights into the developmental impact of childhood maltreatment because they are thought to reflect coordinated maturation of distinct grey matter regions. T1-weighted magnetic resonance images were acquired from 121 young people with emerging mental illness. Diffusion weighted and resting state functional imaging was also acquired from a random subset of the participants (n=62). Ten study-specific SCNs were identified using a whole brain grey matter independent component analysis. The effects of childhood maltreatment and age on average grey matter density and the expression of each SCN were calculated. Childhood maltreatment was linked to age-related decreases in grey matter density across a SCN that overlapped with the default mode and fronto-parietal networks. Resting state functional connectivity and structural connectivity were calculated in the study-specific SCN and across the whole brain. Grey matter covariance was significantly correlated with rsFC across the SCN, and rsFC fully mediated the relationship between grey matter covariance and structural connectivity in the non-maltreated group. A unique association of grey matter covariance with structural connectivity was detected amongst individuals with a history of childhood maltreatment. Perturbation of grey matter development across the default mode and fronto-parietal networks following childhood maltreatment may have significant implications for mental well-being, given the networks' roles in self-referential activity. Cross-modal comparisons suggest reduced grey matter following childhood maltreatment could arise from deficient functional activity earlier in life.

General Galilei Covariant Gaussian Maps

Science.gov (United States)

Gasbarri, Giulio; Toroš, Marko; Bassi, Angelo

2017-09-01

We characterize general non-Markovian Gaussian maps which are covariant under Galilean transformations. In particular, we consider translational and Galilean covariant maps and show that they reduce to the known Holevo result in the Markovian limit. We apply the results to discuss measures of macroscopicity based on classicalization maps, specifically addressing dissipation, Galilean covariance and non-Markovianity. We further suggest a possible generalization of the macroscopicity measure defined by Nimmrichter and Hornberger [Phys. Rev. Lett. 110, 16 (2013)].

SNAP Participation in Preschool-Aged Children and Prevalence of Overweight and Obesity

Science.gov (United States)

Simmons, Shannon; Alexander, Jeffrey L.; Ewing, Helen; Whetzel, Stephanie

2012-01-01

Background: An increased prevalence of overweight and obesity for adults on government-funded nutrition assistance, such as the Supplemental Nutrition Assistance Program (SNAP), has been observed; however, this association among preschool-aged children is not well understood. Longitudinal research designs tracking changes in body mass…

Competing risks and time-dependent covariates

DEFF Research Database (Denmark)

Cortese, Giuliana; Andersen, Per K

2010-01-01

Time-dependent covariates are frequently encountered in regression analysis for event history data and competing risks. They are often essential predictors, which cannot be substituted by time-fixed covariates. This study briefly recalls the different types of time-dependent covariates......, as classified by Kalbfleisch and Prentice [The Statistical Analysis of Failure Time Data, Wiley, New York, 2002] with the intent of clarifying their role and emphasizing the limitations in standard survival models and in the competing risks setting. If random (internal) time-dependent covariates...

Activities of covariance utilization working group

International Nuclear Information System (INIS)

Tsujimoto, Kazufumi

2013-01-01

During the past decade, there has been a interest in the calculational uncertainties induced by nuclear data uncertainties in the neutronics design of advanced nuclear system. The covariance nuclear data is absolutely essential for the uncertainty analysis. In the latest version of JENDL, JENDL-4.0, the covariance data for many nuclides, especially actinide nuclides, was substantialy enhanced. The growing interest in the uncertainty analysis and the covariance data has led to the organisation of the working group for covariance utilization under the JENDL committee. (author)

The prevalence, patterns and predictors of diabetic peripheral neuropathy in a developing country

Directory of Open Access Journals (Sweden)

Katulanda Prasad

2012-05-01

Full Text Available Abstract Prevalence of diabetes mellitus (DM has reached epidemic proportions in Sri Lanka. Presently there are studies on the community prevalence of distal peripheral neuropathy (DPN in Sri Lanka. We describe prevalence, patterns and predictors of DPN in patients with DM in Sri Lanka. Data were collected as part of a national study on DM. In new cases DPN was assessed using the Diabetic-Neuropathy-Symptom (DNS score, while in those with established diabetes both DNS and Toronto-Clinical-Scoring-System (TCSS were used. A binary logistic-regression analysis was performed with ‘presence of DPN’ as the dichomatous dependent variable and other independent co-variants. The study included 528 diabetic patients (191-new cases, with a mean age of 55.0 ± 12.4 years and 37.3% were males, while 18% were from urban areas. Prevalence of DPN according to DNS score among all patients, patients with already established diabetes and newly diagnosed patients were 48.1%, 59.1% and 28.8% respectively. Prevalence of DPN in those with established DM as assessed by TCSS was 24% and the majority had mild DPN (16.6%. The remainder of the abstract is based on subjects with established DM. The prevalence of DPN in males and female was 20.0% and 26.4% respectively. The mean age of those with and without DPN was 62.1 ± 10.8 and 55.1 ± 10.8 years respectively (p 

Androgenetic alopecia in men aged 40-69 years: prevalence and risk factors.

Science.gov (United States)

Severi, G; Sinclair, R; Hopper, J L; English, D R; McCredie, M R E; Boyle, P; Giles, G G

2003-12-01

The epidemiology of androgenetic alopecia (AGA) is not fully understood. Although a strong genetic basis has long been identified, little is known of its non-genetic causes. To estimate the prevalence of and to determine risk factors for AGA in men aged 40-69 years in Australia. Men (n = 1390) were recruited at random from the electoral rolls to serve as controls in a population-based case-control study of prostate cancer. All were interviewed in person and direct observations of AGA were made. Men were grouped into the following categories; no AGA, frontal AGA, vertex AGA and full AGA (frontal and vertex AGA). Epidemiological data collected from these men were used for an analysis of risk factors for each AGA category using unconditional logistic regression with AGA category as the response variable adjusting for age, education and country of birth. The prevalence of vertex and full AGA increased with age from 31% (age 40-55 years) to 53% (age 65-69 years). Conversely, the proportion of men with only frontal AGA was very similar across all age groups (31-33%). No associations were found between pubertal growth spurt or acne, reports of adult body size at time of interview, urinary symptom score, marital status, or current smoking status or duration of smoking and the risk of any form of AGA. The consumption of alcohol was associated with a significant increase in risk of frontal and vertex AGA but not full AGA. Men with vertex AGA had fewer female sexual partners but average ejaculatory frequency did not differ between men in different AGA categories. Reported weight and lean body mass at reaching maturity at about 21 years of age were negatively associated with vertex balding (P for trend body mass at age 21 years would be worthy of further research if they were able to be replicated in other studies.

Quality Quantification of Evaluated Cross Section Covariances

International Nuclear Information System (INIS)

Varet, S.; Dossantos-Uzarralde, P.; Vayatis, N.

2015-01-01

Presently, several methods are used to estimate the covariance matrix of evaluated nuclear cross sections. Because the resulting covariance matrices can be different according to the method used and according to the assumptions of the method, we propose a general and objective approach to quantify the quality of the covariance estimation for evaluated cross sections. The first step consists in defining an objective criterion. The second step is computation of the criterion. In this paper the Kullback-Leibler distance is proposed for the quality quantification of a covariance matrix estimation and its inverse. It is based on the distance to the true covariance matrix. A method based on the bootstrap is presented for the estimation of this criterion, which can be applied with most methods for covariance matrix estimation and without the knowledge of the true covariance matrix. The full approach is illustrated on the 85 Rb nucleus evaluations and the results are then used for a discussion on scoring and Monte Carlo approaches for covariance matrix estimation of the cross section evaluations

Improvement of covariance data for fast reactors

International Nuclear Information System (INIS)

Shibata, Keiichi; Hasegawa, Akira

2000-02-01

We estimated covariances of the JENDL-3.2 data on the nuclides and reactions needed to analyze fast-reactor cores for the past three years, and produced covariance files. The present work was undertaken to re-examine the covariance files and to make some improvements. The covariances improved are the ones for the inelastic scattering cross section of 16 O, the total cross section of 23 Na, the fission cross section of 235 U, the capture cross section of 238 U, and the resolved resonance parameters for 238 U. Moreover, the covariances of 233 U data were newly estimated by the present work. The covariances obtained were compiled in the ENDF-6 format. (author)

The prevalence of age-related maculopathy by geographic region and ethnicity.

Science.gov (United States)

Klein, R; Klein, B E; Cruickshanks, K J

1999-05-01

The prevalence of age-related maculopathy (ARM) varies considerably in different locations and racial/ethnic groups around the world. At present there are insufficient data to determine whether it is likely that these differences in prevalence, especially for the early forms of ARM are due to variations in genetic and environmental factors or due to variations in age of the cohorts and methods used to ascertain and define ARM. In three population-based studies of whites living in Beaver Dam, Wisconsin, Blue Mountains, Australia, and Rotterdam, The Netherlands, in which similar methods of ascertainment and classification were used to detect and define ARM, late ARM was present in 1.2%, 1.4%, and 1.2% of the population less than 86 years of age, respectively. While data from clinical studies suggest that late ARM associated with choroidal neovascularization is rare in blacks compared with whites, some epidemiological studies suggest that late ARM may be similar in blacks and whites. There are still too few data from various ethnic/racial groups around the world and too few population-based data in older Hispanic and Asian populations to make meaningful comparisons. There is a need for further research into the distribution of ARM and its possible causes using similar methodologies to ascertain and define the disease. Further insights will be gained when genotypes associated with ARM are discovered.

Lorentz Covariance of Langevin Equation

International Nuclear Information System (INIS)

Koide, T.; Denicol, G.S.; Kodama, T.

2008-01-01

Relativistic covariance of a Langevin type equation is discussed. The requirement of Lorentz invariance generates an entanglement between the force and noise terms so that the noise itself should not be a covariant quantity. (author)

Gender-specific estimates of COPD prevalence: a systematic review and meta-analysis

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Ntritsos G

2018-05-01

Full Text Available Georgios Ntritsos,1 Jacob Franek,2 Lazaros Belbasis,1 Maria A Christou,1 Georgios Markozannes,1 Pablo Altman,3 Robert Fogel,3 Tobias Sayre,2 Evangelia E Ntzani,1 Evangelos Evangelou1,4 1Clinical and Molecular Epidemiology Unit, Department of Hygiene and Epidemiology, School of Medicine, University of Ioannina, Ioannina, Greece; 2Doctor Evidence, Client Solutions, Santa Monica, CA, USA; 3Global Medical Affairs, Novartis Pharmaceuticals Corporation, East Hanover, NJ, USA; 4Department of Epidemiology and Biostatistics, Imperial College London, London, UK Rationale: COPD has been perceived as being a disease of older men. However, >7 million women are estimated to live with COPD in the USA alone. Despite a growing body of literature suggesting an increasing burden of COPD in women, the evidence is limited. Objectives: To assess and synthesize the available evidence among population-based epidemiologic studies and calculate the global prevalence of COPD in men and women. Materials and methods: A systematic review and meta-analysis reporting gender-specific prevalence of COPD was undertaken. Gender-specific prevalence estimates were abstracted from relevant studies. Associated patient characteristics as well as custom variables pertaining to the diagnostic method and other important epidemiologic covariates were also collected. A Bayesian random-effects meta-analysis was performed investigating gender-specific prevalence of COPD stratified by age, geography, calendar time, study setting, diagnostic method, and disease severity. Measurements and main results: Among 194 eligible studies, summary prevalence was 9.23% (95% credible interval [CrI]: 8.16%–10.36% in men and 6.16% (95% CrI: 5.41%–6.95% in women. Gender prevalences varied widely by the World Health Organization Global Burden of Disease subregions, with the highest female prevalence found in North America (8.07% vs 7.30% and in participants in urban settings (13.03% vs 8.34%. Meta

Prevalence and related factors for anorgasmia among reproductive aged women in Hesarak, Iran

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Mitra Tadayon Najafabady

2011-01-01

Full Text Available INTRODUCTION: Orgasmic dysfunction in women is characterized by persistent or recurrent delay in or absence of orgasm following a normal sexual excitement phase. Research has shown that almost two thirds of women have concerns about their sexual relationship. Sexual dysfunction has many problems for couples; some researchers found that up to 67% of divorces related to sexual disorders. OBJECTIVE: The aim of this cross-sectional study was to assess the prevalence and related factors of anorgasmia among reproductive age Iranian women. METHODS: This study was conducted in 2006-7 in Hesarak, Karaj, Iran. A total of 1200 women were randomly recruited to the study. Sexual satisfaction questions were prepared according to the Enrich Sexual Satisfaction Questionnaire. Orgasms were assessed according to the relevant questions in the Female Sexual Function Index (FSFI questionnaire. The data were analyzed using SPSS version 11; Chi-square, Mann-Whitney and independent t-test were used for statistical purposes. RESULTS: This study showed that the prevalence of anorgasmia among Iranian women in Hesarak, Karaj, was 26.3%. There was a significant difference between the anorgasmic and normal orgasm groups regarding the women's age, age at marriage, duration of marriage and education during puberty (p<0.05. Some psychological factors, e.g. anxiety, fatigue, pain, feeling of guilt, anti-masculine feelings and embarrassment in sexual relationships were higher in the anorgasmic group (p<0.001. DISCUSSION: The results of this study showed that the prevalence of anorgasmia in Hesarak is high and most of the anorgasmic women were highly unsatisfied with their sexual relationship compared to the normal orgasm group. CONCLUSION: The prevalence of anorgasmia among Iranian women in Hesarak, Karaj, is high and some socio-demographic and psychological factors have a strong relationship with anorgasmia.

THE PREVALENCE OF ELECTROCARDIOGRAPHIC INDICATORS AMONG MEN AND WOMEN OF OLDER AGES IN THE RUSSIAN FEDERATION

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G. A. Muromtseva

2016-01-01

Full Text Available Aim. To study the prevalence of ECG ischemic disorders assessed by theMinnesota code on a sample of people over 50 years, depending on gender, age and employment.Material and methods. The results of a survey of a representative sample of the unorganized population of 13 regions, participants of the ESSE-RF program in 2012-2014, were included into the study (n=8334 people; men - 2784, women - 5550. Analysis of the prevalence of ECG changes was carried out by the Minnesota code in groups of 50-54, 55-59 and 60-64 years old, depending on gender and employment (employed and unemployed.Results. Pathological changes were recorded on the ECG more often in men compared to women – Q(QS-wave (5% vs 1.9%, atrial fibrillation (2.1% vs 0.8%; p<0.01, conduction abnormalities (2.7% vs 1.6%; p<0.002 with a maximum in 60-64 years old (4.4% vs 2.6%; p<0.01, respectively. ST segment depression and the T wave abnormalities (myocardial ischemia occurred more often in women than in men (6.9% vs 5.1%, respectively; p<0.001, with a significant increase of these changes in women after 60 years old. The prevalence of ECG abnormalities increases with age. Significant rise of ECG-changes prevalence was found in men at the age of 55-59 years (pathological QQS, myocardial ischemia, left ventricular hypertrophy; and in women – at 60-64 years (myocardial ischemia, atrial fibrillation, conduction abnormalities. Almost two-fold increase in the incidence of arrhythmias and conduction abnormalities was found in men and women aged 60-64 years, regardless of employment status.Conclusion. Given the poor prognosis of ischemic ECG abnormalities, even their low prevalence indicates to unfavorable epidemiological situation among people around retirement age (55-64. These results emphasize the need for practitioners to careful attention to the ECG-abnormalities with poor prognosis in patients pre-retirement and retirement age. They may also be useful for practical public health as a

Soil-transmitted helminths in pre-school-aged and school-aged children in an urban slum: a cross-sectional study of prevalence, distribution, and associated exposures.

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Davis, Stephanie M; Worrell, Caitlin M; Wiegand, Ryan E; Odero, Kennedy O; Suchdev, Parminder S; Ruth, Laird J; Lopez, Gerard; Cosmas, Leonard; Neatherlin, John; Njenga, Sammy M; Montgomery, Joel M; Fox, LeAnne M

2014-11-01

Soil-transmitted helminths (STHs) are controlled by regular mass drug administration. Current practice targets school-age children (SAC) preferentially over pre-school age children (PSAC) and treats large areas as having uniform prevalence. We assessed infection prevalence in SAC and PSAC and spatial infection heterogeneity, using a cross-sectional study in two slum villages in Kibera, Nairobi. Nairobi has low reported STH prevalence. The SAC and PSAC were randomly selected from the International Emerging Infections Program's surveillance platform. Data included residence location and three stools tested by Kato-Katz for STHs. Prevalences among 692 analyzable children were any STH: PSAC 40.5%, SAC 40.7%; Ascaris: PSAC 24.1%, SAC 22.7%; Trichuris: PSAC 24.0%, SAC 28.8%; hookworm slums should be assessed separately in STH mapping. © The American Society of Tropical Medicine and Hygiene.

The prevalence of pelvic floor disorders and their relationship to gender, age, parity and mode of delivery.

Science.gov (United States)

MacLennan, A H; Taylor, A W; Wilson, D H; Wilson, D

2000-12-01

To define the prevalence of pelvic floor disorders in a non-institutionalised community and to determine the relationship to gender, age, parity and mode of delivery. A representative population survey using the 1998 South Australian Health Omnibus Survey. Random selection of 4400 households; 3010 interviews were conducted in the respondents' homes by trained female interviewers. This cross sectional survey included men and women aged 15-97 years. The prevalence of all types of self-reported urinary incontinence in men was 4.4% and in women was 35.3% (Pparity and age. The highest prevalence (51.9%) was reported in women aged 70-74 years. The prevalence of flatus and faecal incontinence was 6.8% and 2.3% in men and 10.9% and 3.5% in women, respectively. Pregnancy (> 20 weeks), regardless of the mode of delivery, greatly increased the prevalence of major pelvic floor dysfunction, defined as any type of incontinence, symptoms of prolapse or previous pelvic floor surgery. Multivariate logistic regression showed that, compared with nulliparity, pelvic floor dysfunction was significantly associated with caesarean section (OR 2.5, 95% CI 1.5-4.3), spontaneous vaginal delivery (OR 3.4, 95% CI 2.4-4.9) and at least one instrumental delivery (OR 4.3, 95% CI 2.8-6.6). The difference between caesarean and instrumental delivery was significant (Pparity and were reported in 19.9% of men and 30.2% of women. Pelvic floor disorders are very common and are strongly associated with female gender, ageing, pregnancy, parity and instrumental delivery. Caesarean delivery is not associated with a significant reduction in long term pelvic floor morbidity compared with spontaneous vaginal delivery.

Epstein-Barr virus (EBV infection in Chinese children: a retrospective study of age-specific prevalence.

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Geng Xiong

Full Text Available BACKGROUND: Epstein-Barr Virus (EBV is a globally prevalent herpesvirus associated with infectious mononucleosis and many malignancies. The survey on EBV prevalence appears to be important to study EBV-related diseases and determine when to administer prophylactic vaccine. The purpose of this retrospective study was to collect baseline information about the prevalence of EBV infection in Chinese children. METHODOLOGY/PRINCIPAL FINDING: We collected 1778 serum samples from healthy children aged 0 to 10, who were enrolled in conventional health and nutrition examinations without any EBV-related symptom in 2012 and 2013 in North China (n = 973 and South China (n = 805. We detected four EBV-specific antibodies, i.e., anti-VCA-IgG and IgM, anti-EBNA-IgG and anti-EA-IgG, by ELISA, representing all of the phases of EBV infection. The overall EBV seroprevalence in samples from North and South China were 80.78% and 79.38% respectively. The EBV seropositivity rates dropped slightly at age 2, and then increased gradually with age. The seroprevalence became stabilized at over 90% after age 8. In this study, the seroprevalence trends between North and South China showed no difference (P>0.05, and the trends of average antibody concentrations were similar as well (P>0.05. CONCLUSIONS/SIGNIFICANCE: EBV seroprevalence became more than 50% before age 3 in Chinese children, and exceed 90% after age 8. This study can be helpful to study the relationship between EBV and EBV-associated diseases, and supportive to EBV vaccine development and implementation.

Covariance descriptor fusion for target detection

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Cukur, Huseyin; Binol, Hamidullah; Bal, Abdullah; Yavuz, Fatih

2016-05-01

Target detection is one of the most important topics for military or civilian applications. In order to address such detection tasks, hyperspectral imaging sensors provide useful images data containing both spatial and spectral information. Target detection has various challenging scenarios for hyperspectral images. To overcome these challenges, covariance descriptor presents many advantages. Detection capability of the conventional covariance descriptor technique can be improved by fusion methods. In this paper, hyperspectral bands are clustered according to inter-bands correlation. Target detection is then realized by fusion of covariance descriptor results based on the band clusters. The proposed combination technique is denoted Covariance Descriptor Fusion (CDF). The efficiency of the CDF is evaluated by applying to hyperspectral imagery to detect man-made objects. The obtained results show that the CDF presents better performance than the conventional covariance descriptor.

Generalized Linear Covariance Analysis

Science.gov (United States)

Carpenter, James R.; Markley, F. Landis

2014-01-01

This talk presents a comprehensive approach to filter modeling for generalized covariance analysis of both batch least-squares and sequential estimators. We review and extend in two directions the results of prior work that allowed for partitioning of the state space into solve-for'' and consider'' parameters, accounted for differences between the formal values and the true values of the measurement noise, process noise, and textita priori solve-for and consider covariances, and explicitly partitioned the errors into subspaces containing only the influence of the measurement noise, process noise, and solve-for and consider covariances. In this work, we explicitly add sensitivity analysis to this prior work, and relax an implicit assumption that the batch estimator's epoch time occurs prior to the definitive span. We also apply the method to an integrated orbit and attitude problem, in which gyro and accelerometer errors, though not estimated, influence the orbit determination performance. We illustrate our results using two graphical presentations, which we call the variance sandpile'' and the sensitivity mosaic,'' and we compare the linear covariance results to confidence intervals associated with ensemble statistics from a Monte Carlo analysis.

Econometric analysis of realized covariation: high frequency based covariance, regression, and correlation in financial economics

DEFF Research Database (Denmark)

Barndorff-Nielsen, Ole Eiler; Shephard, N.

2004-01-01

This paper analyses multivariate high frequency financial data using realized covariation. We provide a new asymptotic distribution theory for standard methods such as regression, correlation analysis, and covariance. It will be based on a fixed interval of time (e.g., a day or week), allowing...... the number of high frequency returns during this period to go to infinity. Our analysis allows us to study how high frequency correlations, regressions, and covariances change through time. In particular we provide confidence intervals for each of these quantities....

Covariant canonical quantization of fields and Bohmian mechanics

International Nuclear Information System (INIS)

Nikolic, H.

2005-01-01

We propose a manifestly covariant canonical method of field quantization based on the classical De Donder-Weyl covariant canonical formulation of field theory. Owing to covariance, the space and time arguments of fields are treated on an equal footing. To achieve both covariance and consistency with standard non-covariant canonical quantization of fields in Minkowski spacetime, it is necessary to adopt a covariant Bohmian formulation of quantum field theory. A preferred foliation of spacetime emerges dynamically owing to a purely quantum effect. The application to a simple time-reparametrization invariant system and quantum gravity is discussed and compared with the conventional non-covariant Wheeler-DeWitt approach. (orig.)

Prevalence of Overweight and Obesity in the Middle-age Population: A Priority for the Health System.

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Khabazkhoob, Mehdi; Emamian, Mohammad Hassan; Hashemi, Hassan; Shariati, Mohammad; Fotouhi, Akbar

2017-06-01

The aim of this study was to determine the prevalence of overweight and obesity and their associated factors in the middle-aged population of Shahroud, North of Iran. In a population-based cross-sectional study with random cluster sampling, 300 clusters of Shahroud (north of Iran) were randomly selected from the 40-64 yr old population of the city, during 2009 and 2010. Upon enrollment, participants were weighed on digital scales and their heights were measured under standard conditions. Overweight and obesity were defined as a body mass index (BMI) of 25-29.9 kg/m 2 and a BMI ≥30 kg/m 2 , respectively. Of the 6311 selected people, 5190 people (82.2%) participated in the study. Their mean age was 50.9±6.2 yr, and 2977 of them were women (57.4%). Age and gender standardized mean BMI in the study population were 28.1 kg/m 2 (95% CI: 27.9-28.2). Age and gender-standardized prevalence of BMI≥25 was 74.4% (95% CI: 73.0-75.8); 43.4% (95% CI 44.8-42.0) were overweight and 31.0% (95% CI 32.5-29.6) were obese. Overweight, Obesity and a BMI ≥25 prevalence's were significantly higher in women ( P <0.001). In the multiple logistic regression models, female gender and higher economic status were significantly correlated with BMI≥25. In addition, people over the age of 54 yr were more likely to have BMI≥25 than those in the 40-44 yr age range ( P <0.001). The prevalence of overweight and obesity in the present study, especially in women, was higher than that reported from previous studies in Iran. Considering prevention, programs for overweight and obesity-related are suggested as a priority for the health system in this population.

Cyberbullying Prevalence among United States Middle and High School Aged Adolescents: A Systematic Review and Quality Assessment

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Selkie, Ellen M.; Fales, Jessica L.; Moreno, Megan A.

2015-01-01

Background Cyberbullying has established links to physical and mental health problems including depression, suicidality, substance use, and somatic symptoms. Quality reporting of cyberbullying prevalence is essential to guide evidence-based policy and prevention priorities. The purpose of this systematic review was to investigate study quality and reported prevalence among cyberbullying research studies conducted in populations of US adolescents of middle and high school age. Methods Searches of peer-reviewed literature published through June 2015 for “cyberbullying” and related terms were conducted using PubMed, PsycINFO, CINAHL Plus, and Web of Science. Included manuscripts reported cyberbullying prevalence in general populations of U.S. adolescents between the ages of 10 and 19. Using a review tool based on the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement, reviewers independently scored study quality on study methods, results reporting, and reported prevalence. Results Search results yielded 1,447 manuscripts; 81 manuscripts representing 58 unique studies were identified as meeting inclusion criteria. Quality scores ranged between 12 and 37 total points out of a possible 42 points (M = 26.7, SD = 4.6). Prevalence rates of cyberbullying ranged as follows: perpetration, 1% to 41%; victimization, 3% to 72%; and overlapping perpetration and victimization, 2.3% to 16.7%. Conclusions Literature on cyberbullying in US middle and high school aged students is robust in quantity but inconsistent in quality and reported prevalence. Consistent definitions and evidence-based measurement tools are needed. PMID:26576821

Proofs of Contracted Length Non-covariance

International Nuclear Information System (INIS)

Strel'tsov, V.N.

1994-01-01

Different proofs of contracted length non covariance are discussed. The way based on the establishment of interval inconstancy (dependence on velocity) seems to be the most convincing one. It is stressed that the known non covariance of the electromagnetic field energy and momentum of a moving charge ('the problem 4/3') is a direct consequence of contracted length non covariance. 8 refs

Gender atypical behavior in Chinese school-aged children: its prevalence and relation to sex, age, and only child status.

Science.gov (United States)

Yu, Lu; Winter, Sam

2011-07-01

This study had three purposes: (a) to compare the prevalence of boys' and girls' gender-atypical behaviors (GABs) in a sample of Chinese school-aged children, (b) to examine the developmental pattern of GABs in Chinese boys and girls over the age range in question (6-12 years), and (c) to test the effects of being an only child on children's GAB expression. Parents of 486 boys and 417 girls completed a Child Play Behavior and Activity Questionnaire (CPBAQ) in regard to their own children, and a demographic information sheet. The frequency distribution for each gender-related behavior was calculated. The associations between sex, age, and only-child status, and CPBAQ scale scores were examined. Although most GABs (by their very nature) were exhibited infrequently in Chinese children, it was found that girls displayed GABs more frequently than boys did. The prevalence of GABs rose for girls as they grew older, but fell slightly for boys. The expressions of GABs in only children did not differ from that in children with siblings. Possible effects of Chinese culture (including the current only-child policy) on children's GABs are discussed.

Covariate analysis of bivariate survival data

Energy Technology Data Exchange (ETDEWEB)

Bennett, L.E.

1992-01-01

The methods developed are used to analyze the effects of covariates on bivariate survival data when censoring and ties are present. The proposed method provides models for bivariate survival data that include differential covariate effects and censored observations. The proposed models are based on an extension of the univariate Buckley-James estimators which replace censored data points by their expected values, conditional on the censoring time and the covariates. For the bivariate situation, it is necessary to determine the expectation of the failure times for one component conditional on the failure or censoring time of the other component. Two different methods have been developed to estimate these expectations. In the semiparametric approach these expectations are determined from a modification of Burke's estimate of the bivariate empirical survival function. In the parametric approach censored data points are also replaced by their conditional expected values where the expected values are determined from a specified parametric distribution. The model estimation will be based on the revised data set, comprised of uncensored components and expected values for the censored components. The variance-covariance matrix for the estimated covariate parameters has also been derived for both the semiparametric and parametric methods. Data from the Demographic and Health Survey was analyzed by these methods. The two outcome variables are post-partum amenorrhea and breastfeeding; education and parity were used as the covariates. Both the covariate parameter estimates and the variance-covariance estimates for the semiparametric and parametric models will be compared. In addition, a multivariate test statistic was used in the semiparametric model to examine contrasts. The significance of the statistic was determined from a bootstrap distribution of the test statistic.

Covariant diagrams for one-loop matching

International Nuclear Information System (INIS)

Zhang, Zhengkang

2016-10-01

We present a diagrammatic formulation of recently-revived covariant functional approaches to one-loop matching from an ultraviolet (UV) theory to a low-energy effective field theory. Various terms following from a covariant derivative expansion (CDE) are represented by diagrams which, unlike conventional Feynman diagrams, involve gaugecovariant quantities and are thus dubbed ''covariant diagrams.'' The use of covariant diagrams helps organize and simplify one-loop matching calculations, which we illustrate with examples. Of particular interest is the derivation of UV model-independent universal results, which reduce matching calculations of specific UV models to applications of master formulas. We show how such derivation can be done in a more concise manner than the previous literature, and discuss how additional structures that are not directly captured by existing universal results, including mixed heavy-light loops, open covariant derivatives, and mixed statistics, can be easily accounted for.

Covariant diagrams for one-loop matching

Energy Technology Data Exchange (ETDEWEB)

Zhang, Zhengkang [Michigan Univ., Ann Arbor, MI (United States). Michigan Center for Theoretical Physics; Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

2016-10-15

We present a diagrammatic formulation of recently-revived covariant functional approaches to one-loop matching from an ultraviolet (UV) theory to a low-energy effective field theory. Various terms following from a covariant derivative expansion (CDE) are represented by diagrams which, unlike conventional Feynman diagrams, involve gaugecovariant quantities and are thus dubbed ''covariant diagrams.'' The use of covariant diagrams helps organize and simplify one-loop matching calculations, which we illustrate with examples. Of particular interest is the derivation of UV model-independent universal results, which reduce matching calculations of specific UV models to applications of master formulas. We show how such derivation can be done in a more concise manner than the previous literature, and discuss how additional structures that are not directly captured by existing universal results, including mixed heavy-light loops, open covariant derivatives, and mixed statistics, can be easily accounted for.

Prevalence and Incidence of Myocardial Infarction and Cerebrovascular Accident in Ageing Persons with Intellectual Disability

Science.gov (United States)

Jansen, J.; Rozeboom, W.; Penning, C.; Evenhuis, H. M.

2013-01-01

Background: Epidemiological information on age-related cardiovascular disease in people with intellectual disability (ID) is scarce and inconclusive. We compared prevalence and incidence of cerebrovascular accident and myocardial infarction over age 50 in a residential population with ID to that in a general practice population. Method: Lifetime…

Variations in Community Prevalence and Determinants of Recreational and Utilitarian Walking in Older Age

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Elizabeth Procter-Gray

2015-01-01

Full Text Available Background. Regular walking is critical to maintaining health in older age. We examined influences of individual and community factors on walking habits in older adults. Methods. We analyzed walking habits among participants of a prospective cohort study of 745 community-dwelling men and women, mainly aged 70 years or older. We estimated community variations in utilitarian and recreational walking, and examined whether the variations were attributable to community differences in individual and environmental factors. Results. Prevalence of recreational walking was relatively uniform while prevalence of utilitarian walking varied across the 16 communities in the study area. Both types of walking were associated with individual health and physical abilities. However, utilitarian walking was also strongly associated with several measures of neighborhood socioeconomic status and access to amenities while recreational walking was not. Conclusions. Utilitarian walking is strongly influenced by neighborhood environment, but intrinsic factors may be more important for recreational walking. Communities with the highest overall walking prevalence were those with the most utilitarian walkers. Public health promotion of regular walking should take this into account.

Age-dependent prevalence of nasopharyngeal carriage of streptococcus pneumoniae before conjugate vaccine introduction: a prediction model based on a meta-analysis.

Science.gov (United States)

Le Polain de Waroux, Olivier; Flasche, Stefan; Prieto-Merino, David; Edmunds, W John

2014-01-01

Data on the prevalence of nasopharyngeal carriage of S.pneumoniae in all age groups are important to help predict the impact of introducing pneumococcal conjugate vaccines (PCV) into routine infant immunization, given the important indirect effect of the vaccine. Yet most carriage studies are limited to children under five years of age. We here explore the association between carriage prevalence and serotype distribution in children aged ≥5 years and in adults compared to children. We conducted a systematic review of studies providing carriage estimates across age groups in healthy populations not previously exposed to PCV, using MEDLINE and Embase. We used Bayesian linear meta-regression models to predict the overall carriage prevalence as well as the prevalence and distribution of vaccine and nonvaccine type (VT and NVT) serotypes in older age groups as a function of that in linear association between the carriage prevalence in pre-school childen (<5 y) and both that in school aged children (5-17 y olds) and in adults. The proportion of VT serotypes isolated from carriers was consistently lower in older age groups and on average about 73% that of children <5 y among 5-17 y olds and adults respectively. We provide a prediction model to infer the carriage prevalence and serotype distribution in 5-17 y olds and adults as a function of that in children <5 years of age. Such predictions are helpful for assessing the potential population-wide effects of vaccination programmes, e.g. via transmission models, and thus assist in the design of future pneumococcal conjugate vaccination strategies.

Low prevalence of abdominal aortic aneurysm in the Seychelles population aged 50 to 65 years.

Science.gov (United States)

Yerly, Patrick; Madeleine, George; Riesen, Walter; Bovet, Pascal

2013-03-01

The prevalence of abdominal aortic aneurysm (AAA) and its risk factors are well known in Western countries but few data are available from low- and middle- income countries. We are not aware of systematically collected population- based data on AAA in the African region. We evaluated the prevalence of AAA in a population- based cardiovascular survey conducted in the Republic of Seychelles in 2004 (Indian Ocean, African region). Among the 353 participants aged 50 to 64 years and screened with ultrasound, the prevalence of AAA was 0.3% (95% CI: 0- 0.9) and the prevalence of ectatic dilatations of the abdominal aorta was 1.5% (95% CI: 0.2- 2.8). The prevalence of AAA in the general population seemed lower in Seychelles than in Western countries, despite a high prevalence in Seychelles of risk factors of AAA, such as smoking (in men), high blood pressure and hypercholesterolaemia.

Covariance and sensitivity data generation at ORNL

International Nuclear Information System (INIS)

Leal, L. C.; Derrien, H.; Larson, N. M.; Alpan, A.

2005-01-01

Covariance data are required to assess uncertainties in design parameters in several nuclear applications. The error estimation of calculated quantities relies on the nuclear data uncertainty information available in the basic nuclear data libraries, such as the US Evaluated Nuclear Data Library, ENDF/B. The uncertainty files in the ENDF/B library are obtained from the analysis of experimental data and are stored as variance and covariance data. In this paper we address the generation of covariance data in the resonance region done with the computer code SAMMY. SAMMY is used in the evaluation of the experimental data in the resolved and unresolved resonance energy regions. The data fitting of cross sections is based on the generalised least-squares formalism (Bayesian theory) together with the resonance formalism described by R-matrix theory. Two approaches are used in SAMMY for the generation of resonance parameter covariance data. In the evaluation process SAMMY generates a set of resonance parameters that fit the data, and, it provides the resonance parameter covariances. For resonance parameter evaluations where there are no resonance parameter covariance data available, the alternative is to use an approach called the 'retroactive' resonance parameter covariance generation. In this paper, we describe the application of the retroactive covariance generation approach for the gadolinium isotopes. (authors)

Prevalence and sociodemographic correlates of metabolic syndrome in school-aged children and their parents in nine Mesoamerican countries.

Science.gov (United States)

Villamor, Eduardo; Finan, Caitlin C; Ramirez-Zea, Manuel; Roman, Ana Victoria

2017-02-01

To ascertain the prevalence and sociodemographic correlates of cardiometabolic risk factors in adults and school-aged children from Mesoamerica. Cross-sectional study with convenience sampling. In adults, metabolic syndrome was defined according to the National Cholesterol Education Program's Adult Treatment Panel III (ATP III) criteria. In children, we calculated a continuous sex- and age-standardized metabolic risk score using variables corresponding to adult ATP III criteria. Metabolic syndrome prevalence in adults and risk score distribution in children were compared across levels of sociodemographic characteristics with use of Poisson and linear regression, respectively. Capital cities of Guatemala, El Salvador, the Dominican Republic, Honduras, Nicaragua, Panama, Costa Rica, the Mexican State of Chiapas (Tuxtla Gutiérrez city) and Belize. Families (n 267), comprising one child aged 7-12 years and their biological parents. The prevalence of metabolic syndrome was 37·9 % among women and 35·3 % among men. The most common component was low HDL cholesterol, 83·3 % in women and 78·9 % in men. Prevalence was positively associated with age. In women, metabolic syndrome was inversely related to education level whereas in men it was positively associated with household food security and height, after adjustment. The metabolic risk score in children was inversely related to parental height, and positively associated with height-for-age and with having parents with the metabolic syndrome. Metabolic syndrome is highly prevalent in Mesoamerica. The burden of metabolic risk factors disproportionately affects women and children of lower socio-economic status and men of higher socio-economic status.

Prevalence of hypertension and hypertension control rates among elderly adults during the cold season in rural Northeast China: a cross-sectional study.

Science.gov (United States)

Kawazoe, Nobuo; Zhang, Xiumin; Chiang, Chifa; Liu, Hongjian; Li, Jinghua; Hirakawa, Yoshihisa; Aoyama, Atsuko

2018-05-01

Objective: The burden of noncommunicable diseases (NCDs) is increasing in China, together with economic development and social changes. The prevalence of risk factors for NCDs, such as overweight/obesity, hypertension, diabetes, and dyslipidemia, is reported to be high even among poor residents of rural areas. We aimed to investigate the prevalence of hypertension among elderly adults in rural Northeast China and the proportion with controlled hypertension among those on antihypertensive medication (hypertension control rate). We also aimed to examine the association of hypertension control with health facilities that provide treatment. Methods: We conducted a community-based cross-sectional study in six rural villages of Northeast China from February to early March, 2012. We interviewed 1593 adults aged 50-69 years and measured their blood pressure. We examined the differences in mean blood pressure between participants who obtained antihypertensive medication from village clinics and those who obtained medication from other sources, using analysis of covariance adjusted for several covariates. Results: The prevalence of hypertension among participants was as high as 63.3%, but the hypertension control rate was only 8.4%. Most villagers (98.1%) were not registered in the chronic disease treatment scheme of the public rural health insurance. The mean systolic blood pressure, adjusted for the covariates, of participants who obtained antihypertensive medication from village clinics was significantly lower than that of participants who obtained medication from township hospitals (by 16.5 mmHg) or from private pharmacies (by 7.3 mmHg). Conclusion: The prevalence of hypertension was high and the hypertension control rate low among elderly villagers during the cold season. As treatment at village clinics, which villagers can access during the cold season seems to be more effective than self-medication or treatment at distant hospitals, improving the quality of treatment

Covariance Evaluation Methodology for Neutron Cross Sections

Energy Technology Data Exchange (ETDEWEB)

Herman,M.; Arcilla, R.; Mattoon, C.M.; Mughabghab, S.F.; Oblozinsky, P.; Pigni, M.; Pritychenko, b.; Songzoni, A.A.

2008-09-01

We present the NNDC-BNL methodology for estimating neutron cross section covariances in thermal, resolved resonance, unresolved resonance and fast neutron regions. The three key elements of the methodology are Atlas of Neutron Resonances, nuclear reaction code EMPIRE, and the Bayesian code implementing Kalman filter concept. The covariance data processing, visualization and distribution capabilities are integral components of the NNDC methodology. We illustrate its application on examples including relatively detailed evaluation of covariances for two individual nuclei and massive production of simple covariance estimates for 307 materials. Certain peculiarities regarding evaluation of covariances for resolved resonances and the consistency between resonance parameter uncertainties and thermal cross section uncertainties are also discussed.

Covariance matrices of experimental data

International Nuclear Information System (INIS)

Perey, F.G.

1978-01-01

A complete statement of the uncertainties in data is given by its covariance matrix. It is shown how the covariance matrix of data can be generated using the information available to obtain their standard deviations. Determination of resonance energies by the time-of-flight method is used as an example. The procedure for combining data when the covariance matrix is non-diagonal is given. The method is illustrated by means of examples taken from the recent literature to obtain an estimate of the energy of the first resonance in carbon and for five resonances of 238 U

New perspective in covariance evaluation for nuclear data

International Nuclear Information System (INIS)

Kanda, Y.

1992-01-01

Methods of nuclear data evaluation have been highly developed during the past decade, especially after introducing the concept of covariance. This makes it utmost important how to evaluate covariance matrices for nuclear data. It can be said that covariance evaluation is just the nuclear data evaluation, because the covariance matrix has quantitatively decisive function in current evaluation methods. The covariance primarily represents experimental uncertainties. However, correlation of individual uncertainties between different data must be taken into account and it can not be conducted without detailed physical considerations on experimental conditions. This procedure depends on the evaluator and the estimated covariance does also. The mathematical properties of the covariance have been intensively discussed. Their physical properties should be studied to apply it to the nuclear data evaluation, and then, in this report, are reviewed to give the base for further development of the covariance application. (orig.)

Serologic prevalence of Toxoplasma gondii in Indian women of child bearing age and effects of social and environmental factors.

Directory of Open Access Journals (Sweden)

Sarman Singh

2014-03-01

Full Text Available BACKGROUND: Seroprevalence and incidence of toxoplasmosis in women of child bearing age has remained a contentious issue in the Indian subcontinent. Different laboratories have used different patient recruitment criteria, methods and variable results, making these data difficult to compare. AIM: To map the point-prevalence and incidence of toxoplasmosis in India. MATERIAL AND METHODS: In this cross-sectional study, a total of 1464 women of fertile age were recruited from 4 regions using similar recruitment plans. This included women from northern (203, southern (512, eastern (250 and western (501 regions of India. All samples were transported to a central laboratory in Delhi and tested using VIDAS technology. Their age, parity, eating habits and other demographic and clinical details were noted. RESULTS: Most women were in the 18-25 years age group (48.3%, followed by 26-30 years (28.2% and 31-35 years (13.66. Few (45 women older than 35 yr. were included. Overall prevalence of anti-Toxoplasma IgG antibodies was seen in 22.40%, with significantly more in married women (25.8% as compared to single women (4.3%. Prevalence increased steadily with age: 18.1% in the 18-25 yr. age group to 40.5% in women older than 40 yr. The prevalence was high (66% in those who resided in mud houses. Region-wise, the highest prevalence was observed in South India (37.3% and the lowest (8.8% in West Indian women. This difference was highly significant (P<0.001. Prevalence was 21.2% in East India and 19.7% in North India. The IgM positivity rate ranged from 0.4% to 2.9% in four study centers. CONCLUSIONS: This pan-India study shows a prevalence rate of 22.4% with a wide variation in four geographical regions ranging from as low as 8.8% to as high as 37.3%. The overall IgM positivity rate was 1.43%, indicating that an estimated 56,737-176,882 children per year are born in India with a possible risk of congenital toxoplasmosis.

Serologic prevalence of Toxoplasma gondii in Indian women of child bearing age and effects of social and environmental factors.

Science.gov (United States)

Singh, Sarman; Munawwar, Arshi; Rao, Sugandhi; Mehta, Sanjay; Hazarika, Naba Kumar

2014-03-01

Seroprevalence and incidence of toxoplasmosis in women of child bearing age has remained a contentious issue in the Indian subcontinent. Different laboratories have used different patient recruitment criteria, methods and variable results, making these data difficult to compare. To map the point-prevalence and incidence of toxoplasmosis in India. In this cross-sectional study, a total of 1464 women of fertile age were recruited from 4 regions using similar recruitment plans. This included women from northern (203), southern (512), eastern (250) and western (501) regions of India. All samples were transported to a central laboratory in Delhi and tested using VIDAS technology. Their age, parity, eating habits and other demographic and clinical details were noted. Most women were in the 18-25 years age group (48.3%), followed by 26-30 years (28.2%) and 31-35 years (13.66). Few (45) women older than 35 yr. were included. Overall prevalence of anti-Toxoplasma IgG antibodies was seen in 22.40%, with significantly more in married women (25.8%) as compared to single women (4.3%). Prevalence increased steadily with age: 18.1% in the 18-25 yr. age group to 40.5% in women older than 40 yr. The prevalence was high (66%) in those who resided in mud houses. Region-wise, the highest prevalence was observed in South India (37.3%) and the lowest (8.8%) in West Indian women. This difference was highly significant (P<0.001). Prevalence was 21.2% in East India and 19.7% in North India. The IgM positivity rate ranged from 0.4% to 2.9% in four study centers. This pan-India study shows a prevalence rate of 22.4% with a wide variation in four geographical regions ranging from as low as 8.8% to as high as 37.3%. The overall IgM positivity rate was 1.43%, indicating that an estimated 56,737-176,882 children per year are born in India with a possible risk of congenital toxoplasmosis.

Prevalence of waterpipe tobacco smoking among population aged 15 years or older, Vietnam, 2010.

Science.gov (United States)

Xuan, Le Thi Thanh; Van Minh, Hoang; Giang, Kim Bao; Nga, Pham Thi Quynh; Hai, Phan Thi; Minh, Nguyen Thac; Hsia, Jason

2013-04-18

The prevalence of waterpipe tobacco smoking is increasing globally and is associated with adverse outcomes requiring tobacco control interventions. We estimated the prevalence of waterpipe tobacco use among adult populations in Vietnam in 2010 and examined its association with sociodemographic factors. We used data from the Global Adult Tobacco Survey (GATS) conducted in Vietnam in 2010. GATS surveyed a national representative sample of adults aged 15 years or older from 11,142 households by using a 2-phase sampling design analogous to a 3-stage stratified cluster sampling. Descriptive statistical analyses and multivariate logistic regression modeling were conducted. A total of 6.4% of Vietnamese aged 15 years or older (representing about 4.1 million adult waterpipe smokers) reported current waterpipe tobacco smoking. The prevalence of waterpipe tobacco smoking was significantly higher among men than women (13% vs 0.1%). Area of residence (rural or urban), age group, asset-based wealth quintile, and geographic region of residence were significantly associated with waterpipe tobacco smoking among men. The significant correlates of current waterpipe tobacco smoking among men were lower education levels, being middle-aged (45-54 years), lower asset-based wealth levels, living in rural areas, not living in the South East and the Mekong River Delta geographic regions, and the belief that smoking does not causes diseases. Rural dwellers who are poor should be targeted in tobacco control programs. Further studies are needed that examine perceptions of the adverse health effects and the cultural factors of waterpipe tobacco smoking.

The prevalence of peripheral arterial disease in middle-aged people with intellectual disabilities

NARCIS (Netherlands)

Zaal-Schuller, I. H.; Goorhuis, A. E. M.; Bock-Sinot, A.; Claassen, I. H. M.; Echteld, M. A.; Evenhuis, H. M.

2015-01-01

Peripheral arterial disease (PAD) is a manifestation of atherosclerosis below the bifurcation of the abdominal aorta. PAD increases the risk of cardiovascular disease and associated mortality. Little is known about the prevalence of PAD in middle-aged persons with intellectual disabilities (ID). We

High Prevalence of Hepatitis B Virus Infection in the Age Range of 20-39 Years Old Individuals in Lome

OpenAIRE

Kolou, Malewe; Katawa, Gnatoulma; Salou, Mounerou; Gozo-Akakpo, Komlan Selom; Dossim, Sika; Kwarteng, Alexander; Prince-David, Mireille

2017-01-01

Background: Hepatitis B is a liver infection caused by the hepatitis B virus (HBV). It affects all women and men irrespective of age. Although sub-Saharan Africa is an area of high prevalence of this disease, data on the prevalence of acute and chronic HBV infections in this region remain to be widely documented. Objective: This study aimed to investigate the prevalence of HBV in relation to age in Centre Hospitalier Universitaire Campus (CHU-C), one of the two teaching hospitals of Lome, Tog...

Trends in state/territorial obesity prevalence by race/ethnicity among U.S. low-income, preschool-aged children.

Science.gov (United States)

Pan, L; Grummer-Strawn, L M; McGuire, L C; Park, S; Blanck, H M

2016-10-01

Understanding state/territorial trends in obesity by race/ethnicity helps focus resources on populations at risk. This study aimed to examine trends in obesity prevalence among low-income, preschool-aged children from 2008 through 2011 in U.S. states and territories by race/ethnicity. We used measured weight and height records of 11.1 million children aged 2-4 years who participated in federally funded health and nutrition programmes in 40 states, the District of Columbia and two U.S. territories. We used logistic regression to examine obesity prevalence trends, controlling for age and sex. From 2008 through 2011, the aggregated obesity prevalence declined among all racial/ethnic groups (decreased by 0.4-0.9%) except American Indians/Alaska Natives (AI/ANs); the largest decrease was among Asians/Pacific Islanders (A/PIs). Declines were significant among non-Hispanic whites in 14 states, non-Hispanic blacks in seven states/territories, Hispanics in 13 states, A/PIs in five states and AI/ANs in one state. Increases were significant among non-Hispanic whites in four states, non-Hispanic blacks in three states, Hispanics in two states and A/PIs in one state. The majority of the states/territories had no change in obesity prevalence. Our findings indicate slight reductions in obesity prevalence and variations in obesity trends, but disparities exist for some states and racial/ethnic groups. © 2015 World Obesity.

Covariant perturbations of Schwarzschild black holes

International Nuclear Information System (INIS)

Clarkson, Chris A; Barrett, Richard K

2003-01-01

We present a new covariant and gauge-invariant perturbation formalism for dealing with spacetimes having spherical symmetry (or some preferred spatial direction) in the background, and apply it to the case of gravitational wave propagation in a Schwarzschild black-hole spacetime. The 1 + 3 covariant approach is extended to a '1 + 1 + 2 covariant sheet' formalism by introducing a radial unit vector in addition to the timelike congruence, and decomposing all covariant quantities with respect to this. The background Schwarzschild solution is discussed and a covariant characterization is given. We give the full first-order system of linearized 1 + 1 + 2 covariant equations, and we show how, by introducing (time and spherical) harmonic functions, these may be reduced to a system of first-order ordinary differential equations and algebraic constraints for the 1 + 1 + 2 variables which may be solved straightforwardly. We show how both odd- and even-parity perturbations may be unified by the discovery of a covariant, frame- and gauge-invariant, transverse-traceless tensor describing gravitational waves, which satisfies a covariant wave equation equivalent to the Regge-Wheeler equation for both even- and odd-parity perturbations. We show how the Zerilli equation may be derived from this tensor, and derive a similar transverse-traceless tensor equation equivalent to this equation. The so-called special quasinormal modes with purely imaginary frequency emerge naturally. The significance of the degrees of freedom in the choice of the two frame vectors is discussed, and we demonstrate that, for a certain frame choice, the underlying dynamics is governed purely by the Regge-Wheeler tensor. The two transverse-traceless Weyl tensors which carry the curvature of gravitational waves are discussed, and we give the closed system of four first-order ordinary differential equations describing their propagation. Finally, we consider the extension of this work to the study of

Depression and Delinquency Covariation in an Accelerated Longitudinal Sample of Adolescents

Science.gov (United States)

Kofler, Michael J.; McCart, Michael R.; Zajac, Kristyn; Ruggiero, Kenneth J.; Saunders, Benjamin E.; Kilpatrick, Dean G.

2011-01-01

Objectives: The current study tested opposing predictions stemming from the failure and acting out theories of depression-delinquency covariation. Method: Participants included a nationwide longitudinal sample of adolescents (N = 3,604) ages 12 to 17. Competing models were tested with cohort-sequential latent growth curve modeling to determine…

Neurofibromatosis 1 prevalence in children aged 9-11 years, Pinar del Río Province, Cuba.

Science.gov (United States)

Orraca, Miladys; Morejón, Griselda; Cabrera, Niurka; Menéndez, Reinaldo; Orraca, Odalys

2014-01-01

INTRODUCTION Neurofibromatosis 1 is one of the most common heritable genetic disorders in humans. It is characterized by formation of neurofibromas, with marked variability in expression. Half the cases are due to autosomal dominant inheritance; the rest arise from de novo mutations. Prevalence varies by population, and prevalence in Cuba is unknown. OBJECTIVE Determine the prevalence of neurofibromatosis 1 in a population of Cuban children aged 9-11 years old in Pinar del Río Province, Cuba. METHODS A descriptive cross-sectional study was carried out in Pinar del Río Province in 2004, in which 19,392 children were assessed for neurofibromatosis 1. The study was conducted in two phases: the first, a survey of the entire population aged 9-11 years by genetic counselors in the province's schools; the second, assessment by clinical geneticists of children who met criteria for referral to the Provincial Medical Genetics Center. Neurofibromatosis 1 cases and first-degree relatives were examined to identify the origin of the mutation (de novo or inherited). Neurofibromatosis 1 prevalence was calculated, as well as history of a first-degree relative with the disease and frequency of several principal clinical signs-café au lait spots, freckles in places unexposed to sunlight, presence of neurofibromas, Lisch nodules and characteristic bone lesions. RESULTS Of the eligible population, 99.3% was screened (10,034 boys and 9358 girls). Active case finding resulted in referral of 200 children to medical geneticists and the disease was confirmed in 17, for a prevalence of one case per 1141 children aged 9-11 years old. Café au lait spots were the most frequent sign (100%), followed by freckles in areas unexposed to sunlight (82.4%) and characteristic bone lesions (41.2%). Only 4 of the 17 cases were previously being treated for the disease. CONCLUSIONS Neurofibromatosis 1 has high prevalence in the group studied in Pinar del Rio Province and most cases are not detected in

HIV prevalence by ethnic group covaries with prevalence of herpes simplex virus-2 and high-risk sex in Uganda: An ecological study.

Science.gov (United States)

Kenyon, Chris R

2018-01-01

HIV prevalence varies from 1.7% to 14.8% between ethnic groups in Uganda. Understanding the factors responsible for this heterogeneity in HIV spread may guide prevention efforts. We evaluated the relationship between HIV prevalence by ethnic group and a range of risk factors as well as the prevalence of herpes simplex virus-2 (HSV-2), syphilis and symptomatic STIs in the 2004/2005 Uganda HIV/AIDS Sero-Behavioural Survey-a two stage, nationally representative, population based survey of 15-59-year-olds. Spearman's correlation was used to assess the relationship between HIV prevalence and each variable. There was a positive association between HIV prevalence and HSV-2, symptomatic STIs and high-risk sex (sex with a non-cohabiting, non-marital partner) for women. Non-significant positive associations were present between HIV and high-risk sex for men and lifetime number of partners for men and women. Variation in sexual behavior may contribute to the variations in HIV, HSV-2 and other STI prevalence by ethnic group in Uganda. Further work is necessary to delineate which combinations of risk factors determine differential STI spread in Uganda.

Covariation in Natural Causal Induction.

Science.gov (United States)

Cheng, Patricia W.; Novick, Laura R.

1991-01-01

Biases and models usually offered by cognitive and social psychology and by philosophy to explain causal induction are evaluated with respect to focal sets (contextually determined sets of events over which covariation is computed). A probabilistic contrast model is proposed as underlying covariation computation in natural causal induction. (SLD)

Age-dependent prevalence of nasopharyngeal carriage of streptococcus pneumoniae before conjugate vaccine introduction: a prediction model based on a meta-analysis.

Directory of Open Access Journals (Sweden)

Olivier Le Polain de Waroux

Full Text Available INTRODUCTION: Data on the prevalence of nasopharyngeal carriage of S.pneumoniae in all age groups are important to help predict the impact of introducing pneumococcal conjugate vaccines (PCV into routine infant immunization, given the important indirect effect of the vaccine. Yet most carriage studies are limited to children under five years of age. We here explore the association between carriage prevalence and serotype distribution in children aged ≥5 years and in adults compared to children. METHODS: We conducted a systematic review of studies providing carriage estimates across age groups in healthy populations not previously exposed to PCV, using MEDLINE and Embase. We used Bayesian linear meta-regression models to predict the overall carriage prevalence as well as the prevalence and distribution of vaccine and nonvaccine type (VT and NVT serotypes in older age groups as a function of that in <5 y olds. RESULTS: Twenty-nine studies compromising of 20,391 individuals were included in the analysis. In all studies nasopharyngeal carriage decreased with increasing age. We found a strong positive linear association between the carriage prevalence in pre-school childen (<5 y and both that in school aged children (5-17 y olds and in adults. The proportion of VT serotypes isolated from carriers was consistently lower in older age groups and on average about 73% that of children <5 y among 5-17 y olds and adults respectively. We provide a prediction model to infer the carriage prevalence and serotype distribution in 5-17 y olds and adults as a function of that in children <5 years of age. CONCLUSION: Such predictions are helpful for assessing the potential population-wide effects of vaccination programmes, e.g. via transmission models, and thus assist in the design of future pneumococcal conjugate vaccination strategies.

Geostatistical Model-Based Estimates of Schistosomiasis Prevalence among Individuals Aged ≤20 Years in West Africa

Science.gov (United States)

Schur, Nadine; Hürlimann, Eveline; Garba, Amadou; Traoré, Mamadou S.; Ndir, Omar; Ratard, Raoult C.; Tchuem Tchuenté, Louis-Albert; Kristensen, Thomas K.; Utzinger, Jürg; Vounatsou, Penelope

2011-01-01

Background Schistosomiasis is a water-based disease that is believed to affect over 200 million people with an estimated 97% of the infections concentrated in Africa. However, these statistics are largely based on population re-adjusted data originally published by Utroska and colleagues more than 20 years ago. Hence, these estimates are outdated due to large-scale preventive chemotherapy programs, improved sanitation, water resources development and management, among other reasons. For planning, coordination, and evaluation of control activities, it is essential to possess reliable schistosomiasis prevalence maps. Methodology We analyzed survey data compiled on a newly established open-access global neglected tropical diseases database (i) to create smooth empirical prevalence maps for Schistosoma mansoni and S. haematobium for individuals aged ≤20 years in West Africa, including Cameroon, and (ii) to derive country-specific prevalence estimates. We used Bayesian geostatistical models based on environmental predictors to take into account potential clustering due to common spatially structured exposures. Prediction at unobserved locations was facilitated by joint kriging. Principal Findings Our models revealed that 50.8 million individuals aged ≤20 years in West Africa are infected with either S. mansoni, or S. haematobium, or both species concurrently. The country prevalence estimates ranged between 0.5% (The Gambia) and 37.1% (Liberia) for S. mansoni, and between 17.6% (The Gambia) and 51.6% (Sierra Leone) for S. haematobium. We observed that the combined prevalence for both schistosome species is two-fold lower in Gambia than previously reported, while we found an almost two-fold higher estimate for Liberia (58.3%) than reported before (30.0%). Our predictions are likely to overestimate overall country prevalence, since modeling was based on children and adolescents up to the age of 20 years who are at highest risk of infection. Conclusion/Significance We

Prevalence of urinary incontinence and lower urinary tract symptoms in school-age children.

Science.gov (United States)

Akil, Ipek Ozunan; Ozmen, Dilek; Cetinkaya, Aynur Cakmakci

2014-07-08

To investigate the prevalence of lower urinary tract symptoms (LUTS) and urinary incontinence (UI) in elementary school aged children in Manisa. Dysfunctional Voiding and Incontinence Scoring System (DVIS) which was developed in Turkey is used. A total of 416 children, 216 (51.9%) male and 200 (48.1%) female were recruited in this study. Mean age of children was 10.35 ± 2.44 years (median10 years). Daytime UI frequency was 6.7% (28 child), nocturnal incontinence 16.6% (69 child) and combined daytime and nocturnal incontinence 4.1% (17 child). There was no statistically significant difference in the prevalence of nocturnal and or daytime UI between male and female gender. Mean DVIS score was 2.65 ± 3.95 and gender did not affect total DVIS points. The mean ages of achieving daytime bowel and bladder control were all significantly correlated with DVIS points. DVIS points were positively correlated with the history of UI of the family. Total points were increased when the father was unemployed. UI negatively influences health related quality of life of the family and child, so it is important that awareness of the UI and symptoms of lower urinary tract dysfunction.

Gray matter volume covariance patterns associated with gait speed in older adults: a multi-cohort MRI study.

Science.gov (United States)

Blumen, Helena M; Brown, Lucy L; Habeck, Christian; Allali, Gilles; Ayers, Emmeline; Beauchet, Olivier; Callisaya, Michele; Lipton, Richard B; Mathuranath, P S; Phan, Thanh G; Pradeep Kumar, V G; Srikanth, Velandai; Verghese, Joe

2018-04-09

Accelerated gait decline in aging is associated with many adverse outcomes, including an increased risk for falls, cognitive decline, and dementia. Yet, the brain structures associated with gait speed, and how they relate to specific cognitive domains, are not well-understood. We examined structural brain correlates of gait speed, and how they relate to processing speed, executive function, and episodic memory in three non-demented and community-dwelling older adult cohorts (Overall N = 352), using voxel-based morphometry and multivariate covariance-based statistics. In all three cohorts, we identified gray matter volume covariance patterns associated with gait speed that included brain stem, precuneus, fusiform, motor, supplementary motor, and prefrontal (particularly ventrolateral prefrontal) cortex regions. Greater expression of these gray matter volume covariance patterns linked to gait speed were associated with better processing speed in all three cohorts, and with better executive function in one cohort. These gray matter covariance patterns linked to gait speed were not associated with episodic memory in any of the cohorts. These findings suggest that gait speed, processing speed (and to some extent executive functions) rely on shared neural systems that are subject to age-related and dementia-related change. The implications of these findings are discussed within the context of the development of interventions to compensate for age-related gait and cognitive decline.

Structural Analysis of Covariance and Correlation Matrices.

Science.gov (United States)

Joreskog, Karl G.

1978-01-01

A general approach to analysis of covariance structures is considered, in which the variances and covariances or correlations of the observed variables are directly expressed in terms of the parameters of interest. The statistical problems of identification, estimation and testing of such covariance or correlation structures are discussed.…

Spatiotemporal noise covariance estimation from limited empirical magnetoencephalographic data

International Nuclear Information System (INIS)

Jun, Sung C; Plis, Sergey M; Ranken, Doug M; Schmidt, David M

2006-01-01

The performance of parametric magnetoencephalography (MEG) and electroencephalography (EEG) source localization approaches can be degraded by the use of poor background noise covariance estimates. In general, estimation of the noise covariance for spatiotemporal analysis is difficult mainly due to the limited noise information available. Furthermore, its estimation requires a large amount of storage and a one-time but very large (and sometimes intractable) calculation or its inverse. To overcome these difficulties, noise covariance models consisting of one pair or a sum of multi-pairs of Kronecker products of spatial covariance and temporal covariance have been proposed. However, these approaches cannot be applied when the noise information is very limited, i.e., the amount of noise information is less than the degrees of freedom of the noise covariance models. A common example of this is when only averaged noise data are available for a limited prestimulus region (typically at most a few hundred milliseconds duration). For such cases, a diagonal spatiotemporal noise covariance model consisting of sensor variances with no spatial or temporal correlation has been the common choice for spatiotemporal analysis. In this work, we propose a different noise covariance model which consists of diagonal spatial noise covariance and Toeplitz temporal noise covariance. It can easily be estimated from limited noise information, and no time-consuming optimization and data-processing are required. Thus, it can be used as an alternative choice when one-pair or multi-pair noise covariance models cannot be estimated due to lack of noise information. To verify its capability we used Bayesian inference dipole analysis and a number of simulated and empirical datasets. We compared this covariance model with other existing covariance models such as conventional diagonal covariance, one-pair and multi-pair noise covariance models, when noise information is sufficient to estimate them. We

The Prevalence of Reading Difficulties among Children in Scholar Age

Directory of Open Access Journals (Sweden)

Maria Rosita Cecilia

2014-10-01

Full Text Available The study investigates the prevalence of reading difficulties among children in scholar age and analyses the socio-demographic characteristics of learners who presented reading difficulties in central Italy. A sample of 623 students 7-11 aged, was assessed with the Italian MT standardized tests. Information on gender, age, handedness, and other socio-demographic variables were also gathered. The study showed that 11% of learners presented poor comprehension skills. The reading speed difficulties were more common than the reading correctness problems: about 7% of children vs 1% were dyslexics due to slow reading. There were no significant differences regarding gender, age. However, dominant hand and the school location seemed to affect the speed difficulties and the comprehension problems. The analyses showed that attending a school located in a rural area was statistically associated with the reading difficulties. Left-handed children were more likely to be slow decoders and/or poor comprehenders. These findings may be used in the early diagnosis of poor readers. These difficulties often have a chronic progression with substantial psychosocial limitations and psychological stress, so children with reading difficulties should be identified as early as possible.

Modifications of Sp(2) covariant superfield quantization

Energy Technology Data Exchange (ETDEWEB)

Gitman, D.M.; Moshin, P.Yu

2003-12-04

We propose a modification of the Sp(2) covariant superfield quantization to realize a superalgebra of generating operators isomorphic to the massless limit of the corresponding superalgebra of the osp(1,2) covariant formalism. The modified scheme ensures the compatibility of the superalgebra of generating operators with extended BRST symmetry without imposing restrictions eliminating superfield components from the quantum action. The formalism coincides with the Sp(2) covariant superfield scheme and with the massless limit of the osp(1,2) covariant quantization in particular cases of gauge-fixing and solutions of the quantum master equations.

Covariant quantizations in plane and curved spaces

International Nuclear Information System (INIS)

Assirati, J.L.M.; Gitman, D.M.

2017-01-01

We present covariant quantization rules for nonsingular finite-dimensional classical theories with flat and curved configuration spaces. In the beginning, we construct a family of covariant quantizations in flat spaces and Cartesian coordinates. This family is parametrized by a function ω(θ), θ element of (1,0), which describes an ambiguity of the quantization. We generalize this construction presenting covariant quantizations of theories with flat configuration spaces but already with arbitrary curvilinear coordinates. Then we construct a so-called minimal family of covariant quantizations for theories with curved configuration spaces. This family of quantizations is parametrized by the same function ω(θ). Finally, we describe a more wide family of covariant quantizations in curved spaces. This family is already parametrized by two functions, the previous one ω(θ) and by an additional function Θ(x,ξ). The above mentioned minimal family is a part at Θ = 1 of the wide family of quantizations. We study constructed quantizations in detail, proving their consistency and covariance. As a physical application, we consider a quantization of a non-relativistic particle moving in a curved space, discussing the problem of a quantum potential. Applying the covariant quantizations in flat spaces to an old problem of constructing quantum Hamiltonian in polar coordinates, we directly obtain a correct result. (orig.)

Covariant quantizations in plane and curved spaces

Energy Technology Data Exchange (ETDEWEB)

Assirati, J.L.M. [University of Sao Paulo, Institute of Physics, Sao Paulo (Brazil); Gitman, D.M. [Tomsk State University, Department of Physics, Tomsk (Russian Federation); P.N. Lebedev Physical Institute, Moscow (Russian Federation); University of Sao Paulo, Institute of Physics, Sao Paulo (Brazil)

2017-07-15

We present covariant quantization rules for nonsingular finite-dimensional classical theories with flat and curved configuration spaces. In the beginning, we construct a family of covariant quantizations in flat spaces and Cartesian coordinates. This family is parametrized by a function ω(θ), θ element of (1,0), which describes an ambiguity of the quantization. We generalize this construction presenting covariant quantizations of theories with flat configuration spaces but already with arbitrary curvilinear coordinates. Then we construct a so-called minimal family of covariant quantizations for theories with curved configuration spaces. This family of quantizations is parametrized by the same function ω(θ). Finally, we describe a more wide family of covariant quantizations in curved spaces. This family is already parametrized by two functions, the previous one ω(θ) and by an additional function Θ(x,ξ). The above mentioned minimal family is a part at Θ = 1 of the wide family of quantizations. We study constructed quantizations in detail, proving their consistency and covariance. As a physical application, we consider a quantization of a non-relativistic particle moving in a curved space, discussing the problem of a quantum potential. Applying the covariant quantizations in flat spaces to an old problem of constructing quantum Hamiltonian in polar coordinates, we directly obtain a correct result. (orig.)

Construction of covariance matrix for experimental data

International Nuclear Information System (INIS)

Liu Tingjin; Zhang Jianhua

1992-01-01

For evaluators and experimenters, the information is complete only in the case when the covariance matrix is given. The covariance matrix of the indirectly measured data has been constructed and discussed. As an example, the covariance matrix of 23 Na(n, 2n) cross section is constructed. A reasonable result is obtained

Smooth individual level covariates adjustment in disease mapping.

Science.gov (United States)

Huque, Md Hamidul; Anderson, Craig; Walton, Richard; Woolford, Samuel; Ryan, Louise

2018-05-01

Spatial models for disease mapping should ideally account for covariates measured both at individual and area levels. The newly available "indiCAR" model fits the popular conditional autoregresssive (CAR) model by accommodating both individual and group level covariates while adjusting for spatial correlation in the disease rates. This algorithm has been shown to be effective but assumes log-linear associations between individual level covariates and outcome. In many studies, the relationship between individual level covariates and the outcome may be non-log-linear, and methods to track such nonlinearity between individual level covariate and outcome in spatial regression modeling are not well developed. In this paper, we propose a new algorithm, smooth-indiCAR, to fit an extension to the popular conditional autoregresssive model that can accommodate both linear and nonlinear individual level covariate effects while adjusting for group level covariates and spatial correlation in the disease rates. In this formulation, the effect of a continuous individual level covariate is accommodated via penalized splines. We describe a two-step estimation procedure to obtain reliable estimates of individual and group level covariate effects where both individual and group level covariate effects are estimated separately. This distributed computing framework enhances its application in the Big Data domain with a large number of individual/group level covariates. We evaluate the performance of smooth-indiCAR through simulation. Our results indicate that the smooth-indiCAR method provides reliable estimates of all regression and random effect parameters. We illustrate our proposed methodology with an analysis of data on neutropenia admissions in New South Wales (NSW), Australia. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development of covariance date for fast reactor cores. 3

International Nuclear Information System (INIS)

Shibata, Keiichi; Hasegawa, Akira

1999-03-01

Covariances have been estimated for nuclear data contained in JENDL-3.2. As for Cr and Ni, the physical quantities for which covariances are deduced are cross sections and the first order Legendre-polynomial coefficient for the angular distribution of elastically scattered neutrons. The covariances were estimated by using the same methodology that had been used in the JENDL-3.2 evaluation in order to keep a consistency between mean values and their covariances. In a case where evaluated data were based on experimental data, the covariances were estimated from the same experimental data. For cross section that had been evaluated by nuclear model calculations, the same model was applied to generate the covariances. The covariances obtained were compiled into ENDF-6 format files. The covariances, which had been prepared by the previous fiscal year, were re-examined, and some improvements were performed. Parts of Fe and 235 U covariances were updated. Covariances of nu-p and nu-d for 241 Pu and of fission neutron spectra for 233,235,238 U and 239,240 Pu were newly added to data files. (author)

Prevalence and causes of work disability among working-age U.S. adults, 2011-2013, NHIS.

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Theis, Kristina A; Roblin, Douglas W; Helmick, Charles G; Luo, Ruiyan

2018-01-01

Chronic conditions are among the major causes of work disability (WD), which is associated with lower employment, less economic activity, and greater dependence on social programs, while limiting access to the benefits of employment participation. We estimated the overall prevalence of WD among working-age (18-64 years) U.S. adults and the most common causes of WD overall and by sex. Next, we estimated the prevalence and most common causes of WD among adults with 12 common chronic conditions by sex and age. We hypothesized that musculoskeletal conditions would be among the most common causes of WD overall and for individuals with other diagnosed chronic conditions. Data were obtained from years 2011, 2012, and 2013 of the National Health Interview Survey. WD was defined by a "yes" response to one or both of: "Does a physical, mental, or emotional problem NOW keep you from working at a job or business?" and "Are you limited in the kind OR amount of work you can do because of a physical, mental or emotional problem?" Overall, 20.1 million adults (10.4% (95% CI = 10.1-10.8) of the working-age population) reported WD. The top three most commonly reported causes of WD were back/neck problems 30.3% (95% CI = 29.1-31.5), depression/anxiety/emotional problems 21.0% (19.9-22.0), and arthritis/rheumatism 18.6 (17.6-19.6). Musculoskeletal conditions were among the three most common causes of WD overall and by age- and sex-specific respondents across diagnosed chronic conditions. Quantifying the prevalence and causes of work disability by age and sex can help prioritize interventions. Published by Elsevier Inc.

Correlation between tea consumption and prevalence of hypertension among Singaporean Chinese residents aged ⩾40 years.

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Li, W; Yang, J; Zhu, X S; Li, S C; Ho, P C

2016-01-01

By a cross-sectional epidemiology study, we attempted to correlate the consumption of tea and/or health supplements, living habits and socio-demographic factors to the prevalence of hypertension among Singaporean Chinese residents. Singaporean Chinese residents aged ⩾40 years were randomly selected and interviewed face-to-face by clinical research assistants. Hypertension was defined as measured systolic blood pressure at least 140 mm Hg and/or diastolic blood pressure at least 90  mmHg or self-reported history/treatment for hypertension. The prevalence of hypertension among the whole investigated population (N=1184, 58.27% females) was 49.73% and the prevalence increased to 66.47% in the sub-population aged ⩾60 years. High risk of hypertension was associated with age ⩾60 years (odds ratio (OR): 4.15-4.19, P25 kg m(-2), OR: 2.10-2.11, Pcoffee intake (OR: 1.44-1.46, Pcoffee could be a risk factor of hypertension. These findings may provide useful information for health promotion to reduce risk of hypertension and warrant further study to confirm and elucidate such association.

The prevalence of overweight, obesity and stunting in school children aged 6-19 years in Beijing, China.

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Wu, Huahong; Li, Hui; Zong, Xinnan

2016-11-01

Childhood/adolescent obesity and stunting are associated with heightened risk of metabolic syndrome. Understanding the prevalence and patterns of stunting, the emergence of overweight/obesity in children and adolescents and the concomitant risk for metabolic syndrome is of critical importance for public health policy. To investigate the prevalence of overweight, obesity and stunting in school children and adolescents aged 6-19 years in Beijing and to compare the differences in screening rates by national and international references. School children aged 6-19 years in Xuanwu, Haidian and Fangshan district were selected. Overweight and obesity in the children was screened for using the International Obesity Task-force (IOTF) and Chinese standards. Stunting was defined as height-for-age Z-score (HAZ) less than -2 using the 2009 Chinese standards and 2007 WHO reference. A total of 99 482 children were included in this survey. The prevalences of overweight and obesity are 17.7% and 14.4% in the Chinese standard, but they are 18.1% and 8.6% in the IOTF standard; there were significant differences between the prevalences of these two standards (p overweight/obesity in boys are all significantly higher than that of girls in every age-group (p children and adolescents (2.6%) according to the Chinese standards, with 2.8% in boys, higher than the 2.5% of girls (p children and adolescents (1.2%) with 1.1% in boys and 1.3% in girls (p overweight/obesity in children and adolescents aged 6-19 years in Beijing was close to western countries, which should be highly valued when considering public health policies and the problem of growth stunting should not be ignored.

Precomputing Process Noise Covariance for Onboard Sequential Filters

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Olson, Corwin G.; Russell, Ryan P.; Carpenter, J. Russell

2017-01-01

Process noise is often used in estimation filters to account for unmodeled and mismodeled accelerations in the dynamics. The process noise covariance acts to inflate the state covariance over propagation intervals, increasing the uncertainty in the state. In scenarios where the acceleration errors change significantly over time, the standard process noise covariance approach can fail to provide effective representation of the state and its uncertainty. Consider covariance analysis techniques provide a method to precompute a process noise covariance profile along a reference trajectory using known model parameter uncertainties. The process noise covariance profile allows significantly improved state estimation and uncertainty representation over the traditional formulation. As a result, estimation performance on par with the consider filter is achieved for trajectories near the reference trajectory without the additional computational cost of the consider filter. The new formulation also has the potential to significantly reduce the trial-and-error tuning currently required of navigation analysts. A linear estimation problem as described in several previous consider covariance analysis studies is used to demonstrate the effectiveness of the precomputed process noise covariance, as well as a nonlinear descent scenario at the asteroid Bennu with optical navigation.

Osteoarthritis Prevalence in Retired National Football League Players With a History of Concussion and Lower Extremity Injury.

Science.gov (United States)

Lynall, Robert C; Pietrosimone, Brian; Kerr, Zachary Y; Mauntel, Timothy C; Mihalik, Jason P; Guskiewicz, Kevin M

2017-06-02

  Dynamic balance deficits have been described postconcussion, even after athletes return to play. Lower extremity (LE) musculoskeletal injury rates increase for up to 1 year after concussion, but the long-term musculoskeletal implications of concussion are unclear.   To (1) examine the association of concussion and LE injury histories with osteoarthritis (OA) prevalence in retired National Football League players and (2) examine the association of concussion and LE injury histories with OA prevalence in those ≤55 years of age.   Case-control study.   Survey.   We administered the Health Survey of Retired National Football League Players, which collects information about demographics, OA, LE injury, and concussion history.   Twelve discrete categories were created based on concussion and LE injury history, ranging from 0 concussions and 0 LE injuries (referent group) to 3+ concussions and 2+ LE injuries. Binomial regression analysis modeled lifetime OA prevalence. Covariates were body mass index, age at the time of the survey, and total years playing professional football.   Complete data were available for 2696 participants. Lifetime OA prevalence was smallest in the referent group (21.1%) and largest in the 3+ concussion and 2+ LE group (50.6%; 2.5 times the referent; 95% confidence interval [CI] = 2.1, 3.1). Participants in all concussion groups (1, 2, 3+) who reported a history of 0 LE injuries had a greater OA prevalence than the referent group. When participants were stratified by age, the ≤55 years of age, 3+ concussions, and 2+ LE injuries group prevalence ratio (3.6; 95% CI = 2.7, 5.2) was larger than that of the >55 years of age, 3+ concussions, and 2+ LE injuries group (1.8; 95% CI = 1.3, 2.4) compared with the respective referent groups.   Concussion with or without a history of LE injury may be an important moderator of OA. Future researchers should seek to better understand the mechanisms that influence the association among

Prevalence of visual impairment and refractive error in school-aged children in South Darfur State of Sudan

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Saif H. Alrasheed

2016-10-01

Full Text Available Background: Global estimates suggest there are almost 19 million visually impaired children worldwide, the major cause being uncorrected refractive error (RE. Aim: To assess the prevalence of visual impairment (VI and RE among Sudanese school-aged children. Setting: Eight randomly selected primary schools from 21 districts in South Darfur State of Sudan were involved. Methods: A school-based cross-sectional study of RE and VI in primary schoolchildren from grades 1 to 8 (children aged 6–15 years was investigated. A Refractive Error Study in Children (RESC protocol was implemented to determine the prevalence of RE and VI in these schoolaged children. Participants were enrolled through stratified multistage cluster sampling of four all-male and four all-female primary schools from South Darfur State of Sudan. Examination procedures followed the RESC protocol, which included visual acuity (VA measurements, binocular vision assessments, retinoscopy and autorefraction under cycloplegia, as well as examination of the external eye, anterior-segment, media and fundus. Results: A total of 1775 children were invited to participate in the study and 1678 were examined resulting in a participation rate of 94.5%. The findings indicated that the prevalence of uncorrected, presenting and best-corrected VA of 6/12 or worse was 6.4% (95% confidence interval [CI], 4.9–7.9, 4.4% (95% CI, 2.9–5.9 and 1.2% (95% CI, 0.3–2.7 respectively. RE was the cause of VI in 57% of participants, retinal disorders in 13.1%, amblyopia in 5.6%, corneal opacity in 0.9%, cataract in 3.7%, with the causes of reduced vision undetermined in 10.3% and various other causes contributed 9.3%. External and anterior-segment abnormalities were observed in 10.2% of children. This was mainly allergic conjunctivitis (5.3% followed by bacterial and viral conjunctivitis (4.2%. The prevalence of myopia (≥|-0.50 D| in one or both eyes was 6.8% (95% CI, 5.3–8.3, hypermetropia (≥ 2 D was

The covariant chiral ring

Energy Technology Data Exchange (ETDEWEB)

Bourget, Antoine; Troost, Jan [Laboratoire de Physique Théorique, École Normale Supérieure, 24 rue Lhomond, 75005 Paris (France)

2016-03-23

We construct a covariant generating function for the spectrum of chiral primaries of symmetric orbifold conformal field theories with N=(4,4) supersymmetry in two dimensions. For seed target spaces K3 and T{sup 4}, the generating functions capture the SO(21) and SO(5) representation theoretic content of the chiral ring respectively. Via string dualities, we relate the transformation properties of the chiral ring under these isometries of the moduli space to the Lorentz covariance of perturbative string partition functions in flat space.

Dietary patterns of Korean adults and the prevalence of metabolic syndrome: a cross-sectional study.

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Woo, Hae Dong; Shin, Aesun; Kim, Jeongseon

2014-01-01

The prevalence of metabolic syndrome has been increasing in Korea and has been associated with dietary habits. The aim of our study was to identify the relationship between dietary patterns and the prevalence of metabolic syndrome. Using a validated food frequency questionnaire, we employed a cross-sectional design to assess the dietary intake of 1257 Korean adults aged 31 to 70 years. To determine the participants' dietary patterns, we considered 37 predefined food groups in principal components analysis. Metabolic syndrome was defined according to the National Cholesterol Education Program Adult Treatment Panel III. The abdominal obesity criterion was modified using Asian guidelines. Prevalence ratios and 95% confidence intervals for the metabolic syndrome were calculated across the quartiles of dietary pattern scores using log binomial regression models. The covariates used in the model were age, sex, total energy intake, tobacco intake, alcohol consumption, and physical activity. The prevalence of metabolic syndrome was 19.8% in men and 14.1% in women. The PCA identified three distinct dietary patterns: the 'traditional' pattern, the 'meat' pattern, and the 'snack' pattern. There was an association of increasing waist circumference and body mass index with increasing score in the meat dietary pattern. The multivariate-adjusted prevalence ratio of metabolic syndrome for the highest quartile of the meat pattern in comparison with the lowest quartile was 1.47 (95% CI: 1.00-2.15, p for trend = 0.016). A positive association between the prevalence of metabolic syndrome and the dietary pattern score was found only for men with the meat dietary pattern (2.15, 95% CI: 1.10-4.21, p for trend = 0.005). The traditional pattern and the snack pattern were not associated with an increased prevalence of metabolic syndrome. The meat dietary pattern was associated with a higher prevalence of metabolic syndrome in Korean male adults.

Dietary patterns of Korean adults and the prevalence of metabolic syndrome: a cross-sectional study.

Directory of Open Access Journals (Sweden)

Hae Dong Woo

Full Text Available The prevalence of metabolic syndrome has been increasing in Korea and has been associated with dietary habits. The aim of our study was to identify the relationship between dietary patterns and the prevalence of metabolic syndrome. Using a validated food frequency questionnaire, we employed a cross-sectional design to assess the dietary intake of 1257 Korean adults aged 31 to 70 years. To determine the participants' dietary patterns, we considered 37 predefined food groups in principal components analysis. Metabolic syndrome was defined according to the National Cholesterol Education Program Adult Treatment Panel III. The abdominal obesity criterion was modified using Asian guidelines. Prevalence ratios and 95% confidence intervals for the metabolic syndrome were calculated across the quartiles of dietary pattern scores using log binomial regression models. The covariates used in the model were age, sex, total energy intake, tobacco intake, alcohol consumption, and physical activity. The prevalence of metabolic syndrome was 19.8% in men and 14.1% in women. The PCA identified three distinct dietary patterns: the 'traditional' pattern, the 'meat' pattern, and the 'snack' pattern. There was an association of increasing waist circumference and body mass index with increasing score in the meat dietary pattern. The multivariate-adjusted prevalence ratio of metabolic syndrome for the highest quartile of the meat pattern in comparison with the lowest quartile was 1.47 (95% CI: 1.00-2.15, p for trend = 0.016. A positive association between the prevalence of metabolic syndrome and the dietary pattern score was found only for men with the meat dietary pattern (2.15, 95% CI: 1.10-4.21, p for trend = 0.005. The traditional pattern and the snack pattern were not associated with an increased prevalence of metabolic syndrome. The meat dietary pattern was associated with a higher prevalence of metabolic syndrome in Korean male adults.

GLq(N)-covariant quantum algebras and covariant differential calculus

International Nuclear Information System (INIS)

Isaev, A.P.; Pyatov, P.N.

1992-01-01

GL q (N)-covariant quantum algebras with generators satisfying quadratic polynomial relations are considered. It is that, up to some innessential arbitrariness, there are only two kinds of such quantum algebras, namely, the algebras with q-deformed commutation and q-deformed anticommutation relations. 25 refs

Introduction to covariant formulation of superstring (field) theory

International Nuclear Information System (INIS)

Anon.

1987-01-01

The author discusses covariant formulation of superstring theories based on BRS invariance. New formulation of superstring was constructed by Green and Schwarz in the light-cone gauge first and then a covariant action was discovered. The covariant action has some interesting geometrical interpretation, however, covariant quantizations are difficult to perform because of existence of local supersymmetries. Introducing extra variables into the action, a modified action has been proposed. However, it would be difficult to prescribe constraints to define a physical subspace, or to reproduce the correct physical spectrum. Hence the old formulation, i.e., the Neveu-Schwarz-Ramond (NSR) model for covariant quantization is used. The author begins by quantizing the NSR model in a covariant way using BRS charges. Then the author discusses the field theory of (free) superstring

Prevalence of anemia and correlated factors in the reproductive age women in rural areas of tabas.

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Majid Sadeghian

2013-09-01

Full Text Available To find out the prevalence and relationship of anemia in reproductive age women in rural area of Tabas, center of Iran. Iron deficiency anemia is the most common nutritional problem, affecting about 41.8% of pregnant and 30.2% of non-pregnant women worldwide.A cross-sectional study was conducted on the random sample of 382 reproductive age women in rural areas of Tabas in March 2010. Independent sample t-test, one way analysis of variance (ANOVA and logistic regression were applied for the data analysis.The obtained data revealed a total response rate of 13.8% for prevalence of anemia, while 14.5% and 5.9% belonged to non-pregnant and pregnant participants, respectively. Low socioeconomic status (odds ratio 3.35 and high parity index (odds ratio 2.31 were associated with higher prevalence of anemia.Although this study was conducted in a rural area of Tabas, where their average incomes were lower than average income of major cities in Iran, the prevalence of anemia was lower than the rate reported in previous studies carried out in other locations of Iran, even in high risk (pregnant women groups.

Prevalence, and Intellectual Outcome of Unilateral Focal Cortical Brain Damage as a Function of Age, Sex and Aetiology

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C. M. J. Braun

2002-01-01

Full Text Available Neurologists and neuropsychologists are aware that aging men are more at risk than women for brain damage, principally because of the well known male-predominant risk for cardiovascular disease and related cerebrovascular accidents. However, a disproportion in prevalence of brain damage between the sexes in childhood may be less suspected. Furthermore, sex-specific risk for other aetiologies of brain damage may be little known, whether in the pediatric or adult populations. Proposals of a sex difference in cognitive recovery from brain damage have also been controversial. Six hundred and thirty five “consecutive” cases with cortical focal lesions including cases of all ages and both sexes were reviewed. Aetiology of the lesion was determined for each case as was postlesion IQ. Risk was highly male prevalent in all age groups, with a predominance of cardiovascular aetiology explaining much of the adult male prevalence. However, several other aetiological categories were significantly male prevalent in juveniles (mitotic, traumatic, dysplasic and adults (mitotic, traumatic. There was no sex difference in outcome (i.e., postlesion IQ of these cortical brain lesions for the cohort as a whole, after statistical removal of the influence of lesion extent, aetiology and presence of epilepsy. Mechanisms potentially responsible for sex differences in prevalence, aetiology of brain damage, and recovery, are reviewed and discussed.

Graphical representation of covariant-contravariant modal formulae

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Miguel Palomino

2011-08-01

Full Text Available Covariant-contravariant simulation is a combination of standard (covariant simulation, its contravariant counterpart and bisimulation. We have previously studied its logical characterization by means of the covariant-contravariant modal logic. Moreover, we have investigated the relationships between this model and that of modal transition systems, where two kinds of transitions (the so-called may and must transitions were combined in order to obtain a simple framework to express a notion of refinement over state-transition models. In a classic paper, Boudol and Larsen established a precise connection between the graphical approach, by means of modal transition systems, and the logical approach, based on Hennessy-Milner logic without negation, to system specification. They obtained a (graphical representation theorem proving that a formula can be represented by a term if, and only if, it is consistent and prime. We show in this paper that the formulae from the covariant-contravariant modal logic that admit a "graphical" representation by means of processes, modulo the covariant-contravariant simulation preorder, are also the consistent and prime ones. In order to obtain the desired graphical representation result, we first restrict ourselves to the case of covariant-contravariant systems without bivariant actions. Bivariant actions can be incorporated later by means of an encoding that splits each bivariant action into its covariant and its contravariant parts.

Piecewise linear regression splines with hyperbolic covariates

International Nuclear Information System (INIS)

Cologne, John B.; Sposto, Richard

1992-09-01

Consider the problem of fitting a curve to data that exhibit a multiphase linear response with smooth transitions between phases. We propose substituting hyperbolas as covariates in piecewise linear regression splines to obtain curves that are smoothly joined. The method provides an intuitive and easy way to extend the two-phase linear hyperbolic response model of Griffiths and Miller and Watts and Bacon to accommodate more than two linear segments. The resulting regression spline with hyperbolic covariates may be fit by nonlinear regression methods to estimate the degree of curvature between adjoining linear segments. The added complexity of fitting nonlinear, as opposed to linear, regression models is not great. The extra effort is particularly worthwhile when investigators are unwilling to assume that the slope of the response changes abruptly at the join points. We can also estimate the join points (the values of the abscissas where the linear segments would intersect if extrapolated) if their number and approximate locations may be presumed known. An example using data on changing age at menarche in a cohort of Japanese women illustrates the use of the method for exploratory data analysis. (author)

Age, cohort and period effects in the prevalence of sleep disturbances among older people: the impact of economic downturn.

Science.gov (United States)

Dregan, Alex; Armstrong, David

2009-11-01

Using two longitudinal and nationally representative datasets, this study employs a cross-cohort analysis to examine age, cohort and period effects in the prevalence of sleep loss through worry for people over the age of 50 in the UK. The likelihood of reporting sleep loss through worry is calculated at two time-points for 7785 respondents from the Health and Activity Survey (HALs) and 21,834 respondents from the English Longitudinal Study of Ageing (ELSA), with baseline information on sleep loss through worry. Descriptive statistical methods were applied to determine the prevalence rates in sleep loss through worry at each survey within both datasets. The results of analysis reveal that sleep loss through worry declined with age, but this pattern was tempered by a temporary increase in the early 1990s. The contemporary economic downturn is suggested as a possible explanation for the significant increase in the prevalence of sleep loss through worry in 1991.

Prevalence, intensity and extent of Oral Impacts on Daily Performances associated with self-perceived malocclusion in 11-12-year-old children

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Flores-Mir Carlos

2007-05-01

Full Text Available Abstract Background To determine the prevalence, intensity and extent of the Oral Impacts on Daily Performances associated with self-perceived malocclusion among Peruvian schoolchildren. Methods Eight hundred and five children aged 11 to 12 years attending 4 of 7 randomly selected schools linked to a Health Centre in Lima, Peru, participated in the study. The Spanish (PeruChild-OIDP was used to assess the prevalence, intensity and extent of oral impacts on 8 daily performances (eating, speaking, teeth cleaning, sleeping, smiling, studying, emotion and social contact. Self-perceived malocclusion included complaints about position of teeth, spacing of teeth and deformity of mouth or face. The prevalence of oral impacts was compared by covariables using the Chi-square test, whereas the intensity and extent of oral impacts were compared by covariables through the Mann-Whitney test. Results Only 15.5% of children reported impacts associated with self-perceived malocclusion during the last 3 months. Of them, 18.4% reported impacts of severe or very severe intensity and 76.0% reported impacts on only one daily performance. Psychosocial activities such as smiling, emotion and social contact were the most frequently and severely impacted everyday activities. Conclusion Impacts of self-perceived malocclusion primarily affected psychological and social everyday activities. These findings provide further evidence to support the importance of psychological and social components of oral health on children's lives.

Geography matters: the prevalence of diabetes in the Auckland Region by age, gender and ethnicity.

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Warin, Briar; Exeter, Daniel J; Zhao, Jinfeng; Kenealy, Timothy; Wells, Susan

2016-06-10

To determine whether the prevalence of diagnosed diabetes in the greater Auckland Region varies by General Electoral District (GED). Using encrypted National Health Identifiers and record linkage of routine health datasets, we identified a regional cohort of people with diagnosed diabetes in 2011 from inpatient records and medication dispensing. The geographical unit of a person's residence (meshblock) was used to determine the GED of residence. We calculated prevalence estimates and 95% confidence intervals and used binary logistic regression to map geographical variations in diabetes. An estimated 63,014 people had diagnosed diabetes in Auckland in 2011, a prevalence of 8.5% of the adult population ≥30 years of age. We found significant variation in diabetes prevalence by age, gender, ethnicity and GED. There was a more than five-fold difference in the unadjusted prevalence of diabetes by GED, ranging from 3.2% (3.1 to 3.4%) in the North Shore to 17.3% (16.8 to 17.7%) in Mangere. Such variations remained after binary logistic regression adjusting for socio-demographic variables. Compared to New Zealand Europeans, Indian people had the highest odds of having diabetes at 3.85 (3.73 to 3.97), while the odds of people living in the most deprived areas having diabetes was nearly twice that of those living in least deprived areas (OR 1.93, [1.87 to 1.99]). Geographic variations in diabetes remained after adjusting for socio-demographic circumstances: people living in GEDs in south-west Auckland were at least 60% more likely than people living in the North Shore GED to have diabetes. There is significant variation in the prevalence of diabetes by GED in Auckland that persists across strata of age group, gender and ethnicity, and persists after controlling for these same variables. These inequities should prompt action by politicians, policymakers, funders, health providers and communities for interventions aimed at reducing such inequities. Geography and its

Multivariate covariance generalized linear models

DEFF Research Database (Denmark)

Bonat, W. H.; Jørgensen, Bent

2016-01-01

are fitted by using an efficient Newton scoring algorithm based on quasi-likelihood and Pearson estimating functions, using only second-moment assumptions. This provides a unified approach to a wide variety of types of response variables and covariance structures, including multivariate extensions......We propose a general framework for non-normal multivariate data analysis called multivariate covariance generalized linear models, designed to handle multivariate response variables, along with a wide range of temporal and spatial correlation structures defined in terms of a covariance link...... function combined with a matrix linear predictor involving known matrices. The method is motivated by three data examples that are not easily handled by existing methods. The first example concerns multivariate count data, the second involves response variables of mixed types, combined with repeated...

The prevalence of PFS and prevalence and characteristics of reported food allergy; a survey of UK adults aged 18-75 incorporating a validated PFS diagnostic questionnaire.

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Skypala, I J; Bull, S; Deegan, K; Gruffydd-Jones, K; Holmes, S; Small, I; Emery, P W; Durham, S R

2013-08-01

Pollen-food syndrome (PFS), a food allergy affecting pollen-sensitized individuals, is likely to be the most prevalent food allergy in adults, estimated to affect 50-90% of people allergic to birch tree pollen. A validated PFS diagnostic questionnaire (PFSDQ2) was used to determine the prevalence of PFS and also to characterize those who report reactions to foods. Five UK General practices each sent the PFSDQ2 by post to 2000 patients aged 18-75 years randomly selected from their practice database. The validated questionnaire was accompanied by an additional set of questions to ascertain the demographic of the population, the foods involved and the age of onset. There were 3590 subjects who returned completed questionnaires, with an average return rate from each practice of 36% (range 22-47%). Of these, 73 were diagnosed with PFS according to the questionnaire (PFS+ve) giving a population prevalence of 2%. A further 482 subjects reported reactions to foods but did not fulfil the diagnostic criteria for PFS. The greatest prevalence of PFS was in the Croydon (SE England) urban practice (4.1%) and the lowest in the Aberdeen (Scotland) urban practice (0.8%) (P < 0.001).The most frequently reported trigger foods were apples, hazelnuts and kiwifruit and the majority of those with PFS first experienced symptoms below the age of 20 years. PFS+ve subjects were also more likely to be female and have a higher socio-economic status than those who did not report reactions to foods. The UK prevalence of PFS was 2%, although this varied according to the location of the practice population. The majority of PFS+ve subjects first reported symptoms in their teens. The reported age of onset has important implications for the diagnosis of primary and cross-reactive peanut and tree nut allergies in teenagers and young adults. The continuing rise in aeroallergen sensitization is likely to result in an increased frequency of PFS presenting in both primary and secondary care. © 2013

The national and subnational prevalence and burden of age-related macular degeneration in China.

Science.gov (United States)

Song, Peige; Du, Yuhang; Chan, Kit Yee; Theodoratou, Evropi; Rudan, Igor

2017-12-01

Age-related macular degeneration (AMD) is the third most common cause of blindness, and the fourth leading cause of visual impairment worldwide, but little is known about the burden of this disease in the most populous country-China. This study provides the first comprehensive estimates of the prevalence and burden of AMD in China from 1990 to 2015, with projections till 2050. In this study, a systematic review and meta-analysis was conducted to estimate the prevalence of AMD in China. China National Knowledge Infrastructure (CNKI), Wanfang, Chinese Biomedicine Literature Database (CBM-SinoMed), PubMed, Embase and Medline were searched before September 2016. Multilevel mixed-effect meta-regression was performed to define the prevalence rates of AMD and its subtypes. UN population data were used to estimate and project the number of people affected from 1990 to 2050. Based on different demographic and geographic features, the national burden of AMD in 2000 and 2010 was distributed to different regions in China. Our search returned 2016 citations, of which 25 met the inclusion criteria. The prevalence of any AMD ranged from 2.44% (95% CI = 1.85-3.22) in people aged 45-49 years to 18.98% (95% CI = 15.05-23.66) in people aged 85-89 years. Prevalence of early AMD ranged from 1.79% (95% CI = 1.05-3.02) to 10.05% (95% CI = 6.17-15.97), and, in the case of late AMD, from 0.38% (95% CI = 0.16-0.97) to 3.88% (95% CI = 1.68-9.13). In late AMD, the prevalence of geographic atrophy (GA) was 0.15% (95% CI = 0.05-0.47) in people aged 45-49 years and 1.09% (95% CI = 0.35-3.36) in those aged 85-89 years, and the prevalence of neovascular AMD (NVAMD) ranged between 0.24% (95% CI = 0.11-0.50) and 2.79% (95% CI = 1.33-5.77). The number of people with any AMD was 12.01 million (95% CI = 9.29-15.46) in 1990 and 26.65 million (95% CI = 20.62-34.27) in 2015. Within the same period, the number of people with early AMD increased from 9

Prevalence of triangular fibrocartilage complex abnormalities regardless of symptoms rise with age: systematic review and pooled analysis.

Science.gov (United States)

Chan, Jimmy J; Teunis, Teun; Ring, David

2014-12-01

Triangular fibrocartilage complex abnormalities seem to be more common with age, but the degree to which this is so, and the degree to which the presence of an abnormality is associated with symptoms, are topics of controversy. We wished to perform a systematic review to determine the prevalence of triangular fibrocartilage complex abnormalities, and to determine if the prevalence of abnormalities are greater with increasing age. In addition, we stratified age groups based on symptoms. We searched MEDLINE, EMBASE, and the Cochrane Library through August 15, 2013. Studies that reported triangular fibrocartilage complex abnormalities by age were included. Fifteen studies including 977 wrists met our criteria and reported a total of 368 (38%) triangular fibrocartilage complex abnormalities. Eight studies included symptomatic patients; the remainder studied cadavers (six studies) or asymptomatic volunteers (one study). Patients were divided into four age groups (fibrocartilage complex abnormalities increased with age, from 27% (80/301) in patients younger than 30 years to 49% (130/265) in patients 70 years and older (p fibrocartilage complex prevalence abnormality increased from 15% (24/159) to 49% (129/263) in the same age groups (p fibrocartilage complex abnormalities are common in symptomatic and asymptomatic wrists, and they are increasingly common with age. As in all situations where abnormalities are so common that they may be incidental, we need (1) a reliable and accurate method for determining whether these abnormalities are the cause of symptoms; and (2) evidence that treatment of these abnormalities improves symptoms better than placebo. Level III, prognostic study. See the Instructions for Authors for a complete description of levels of evidence.

Age-related trends in psychotropic medication use among very young children in foster care.

Science.gov (United States)

dosReis, Susan; Tai, Ming-Hui; Goffman, David; Lynch, Sean E; Reeves, Gloria; Shaw, Terry

2014-12-01

The specific objectives were to investigate changes in the prevalence of psychotropic medication use for each year increase in age from three to six years old among children in foster care and to examine time-varying odds of longer duration of use by each year of age. A retrospective analysis of data on mental health and pharmacy services was conducted for 1,491 children age six and younger who were in foster care in 2010 and had at least 365 days in foster care during 2009-2011. A total of 178 children received at least one psychotropic medication from 2009 through 2011. Psychotropic prevalence and average days of use were calculated for each therapeutic class. Longitudinal regression models assessed the time-varying relationship between year of age and duration of use, controlling for demographic and clinical covariates. Approximately 12% of children age six and younger in foster care for 365 days or more received at least one psychotropic medication over the three-year study period. Prevalence of ADHD medication and antipsychotic medication and duration increased with each year of age (p<.001). In adjusted longitudinal models, each year increase in age was associated with a nearly twofold higher likelihood of longer duration of antipsychotic and ADHD medication use. Young children who initiated antipsychotic and ADHD medications before the age of six continued to receive them for longer periods of time. There is a critical need for long-term studies to evaluate the effect of chronic exposure on children's health and well-being.

Covariant single-hole optical potential

International Nuclear Information System (INIS)

Kam, J. de

1982-01-01

In this investigation a covariant optical potential model is constructed for scattering processes of mesons from nuclei in which the meson interacts repeatedly with one of the target nucleons. The nuclear binding interactions in the intermediate scattering state are consistently taken into account. In particular for pions and K - projectiles this is important in view of the strong energy dependence of the elementary projectile-nucleon amplitude. Furthermore, this optical potential satisfies unitarity and relativistic covariance. The starting point in our discussion is the three-body model for the optical potential. To obtain a practical covariant theory I formulate the three-body model as a relativistic quasi two-body problem. Expressions for the transition interactions and propagators in the quasi two-body equations are found by imposing the correct s-channel unitarity relations and by using dispersion integrals. This is done in such a way that the correct non-relativistic limit is obtained, avoiding clustering problems. Corrections to the quasi two-body treatment from the Pauli principle and the required ground-state exclusion are taken into account. The covariant equations that we arrive at are amenable to practical calculations. (orig.)

Prevalence of parent-reported immediate hypersensitivity food allergy in Chilean school-aged children.

Science.gov (United States)

Hoyos-Bachiloglu, R; Ivanovic-Zuvic, D; Álvarez, J; Linn, K; Thöne, N; de los Ángeles Paul, M; Borzutzky, A

2014-01-01

Food allergies (FAs) affect 2-4% of school-aged children in developed countries and strongly impact their quality of life. The prevalence of FA in Chile remains unknown. Cross-sectional survey study of 488 parents of school-aged children from Santiago who were asked to complete a FA screening questionnaire. Parents who reported symptoms suggestive of FA were contacted to answer a second in-depth questionnaire to determine immediate hypersensitivity FA prevalence and clinical characteristics of school-aged Chilean children. A total of 455 parents answered the screening questionnaire: 13% reported recurrent symptoms to a particular food and 6% reported FA. Forty-three screening questionnaires (9%) were found to be suggestive of FA. Parents of 40 children answered the second questionnaire; 25 were considered by authors to have FA. FA rate was 5.5% (95% CI: 3.6-7.9). Foods reported to frequently cause FA included walnut, peanut, egg, chocolate, avocado, and banana. Children with FA had more asthma (20% vs. 7%, Phistory compatible with anaphylaxis. Of 13 children who sought medical attention, 70% were diagnosed with FA; none were advised to acquire an epinephrine autoinjector. Up to 5.5% of school-aged Chilean children may suffer from FA, most frequently to walnut and peanut. It is critical to raise awareness in Chile regarding FA and recognition of anaphylaxis, and promote epinephrine autoinjectors in affected children. Copyright © 2013 SEICAP. Published by Elsevier Espana. All rights reserved.

Nuclear data covariances in the Indian context

International Nuclear Information System (INIS)

Ganesan, S.

2014-01-01

The topic of covariances is recognized as an important part of several ongoing nuclear data science activities, since 2007, in the Nuclear Data Physics Centre of India (NDPCI). A Phase-1 project in collaboration with the Statistics department in Manipal University, Karnataka (Prof. K.M. Prasad and Prof. S. Nair) on nuclear data covariances was executed successfully during 2007-2011 period. In Phase-I, the NDPCI has conducted three national Theme meetings sponsored by the DAE-BRNS in 2008, 2010 and 2013 on nuclear data covariances. In Phase-1, the emphasis was on a thorough basic understanding of the concept of covariances including assigning uncertainties to experimental data in terms of partial errors and micro correlations, through a study and a detailed discussion of open literature. Towards the end of Phase-1, measurements and a first time covariance analysis of cross-sections for 58 Ni (n, p) 58 Co reaction measured in Mumbai Pelletron accelerator using 7 Li (p,n) reactions as neutron source in the MeV energy region were performed under a PhD programme on nuclear data covariances in which enrolled are two students, Shri B.S. Shivashankar and Ms. Shanti Sheela. India is also successfully evolving a team of young researchers to code nuclear data of uncertainties, with the perspectives on covariances, in the IAEA-EXFOR format. A Phase-II DAE-BRNS-NDPCI proposal of project at Manipal has been submitted and the proposal is undergoing a peer-review at this time. In Phase-2, modern nuclear data evaluation techniques that including covariances will be further studied as a research and development effort, as a first time effort. These efforts include the use of techniques such as that of the Kalman filter. Presently, a 48 hours lecture series on treatment of errors and their propagation is being formulated under auspices of the Homi Bhabha National Institute. The talk describes the progress achieved thus far in the learning curve of the above-mentioned and exciting

AFCI-2.0 Neutron Cross Section Covariance Library

Energy Technology Data Exchange (ETDEWEB)

Herman, M.; Herman, M; Oblozinsky, P.; Mattoon, C.M.; Pigni, M.; Hoblit, S.; Mughabghab, S.F.; Sonzogni, A.; Talou, P.; Chadwick, M.B.; Hale, G.M.; Kahler, A.C.; Kawano, T.; Little, R.C.; Yount, P.G.

2011-03-01

The cross section covariance library has been under development by BNL-LANL collaborative effort over the last three years. The project builds on two covariance libraries developed earlier, with considerable input from BNL and LANL. In 2006, international effort under WPEC Subgroup 26 produced BOLNA covariance library by putting together data, often preliminary, from various sources for most important materials for nuclear reactor technology. This was followed in 2007 by collaborative effort of four US national laboratories to produce covariances, often of modest quality - hence the name low-fidelity, for virtually complete set of materials included in ENDF/B-VII.0. The present project is focusing on covariances of 4-5 major reaction channels for 110 materials of importance for power reactors. The work started under Global Nuclear Energy Partnership (GNEP) in 2008, which changed to Advanced Fuel Cycle Initiative (AFCI) in 2009. With the 2011 release the name has changed to the Covariance Multigroup Matrix for Advanced Reactor Applications (COMMARA) version 2.0. The primary purpose of the library is to provide covariances for AFCI data adjustment project, which is focusing on the needs of fast advanced burner reactors. Responsibility of BNL was defined as developing covariances for structural materials and fission products, management of the library and coordination of the work; LANL responsibility was defined as covariances for light nuclei and actinides. The COMMARA-2.0 covariance library has been developed by BNL-LANL collaboration for Advanced Fuel Cycle Initiative applications over the period of three years, 2008-2010. It contains covariances for 110 materials relevant to fast reactor R&D. The library is to be used together with the ENDF/B-VII.0 central values of the latest official release of US files of evaluated neutron cross sections. COMMARA-2.0 library contains neutron cross section covariances for 12 light nuclei (coolants and moderators), 78 structural

AFCI-2.0 Neutron Cross Section Covariance Library

International Nuclear Information System (INIS)

Herman, M.; Oblozinsky, P.; Mattoon, C.M.; Pigni, M.; Hoblit, S.; Mughabghab, S.F.; Sonzogni, A.; Talou, P.; Chadwick, M.B.; Hale, G.M.; Kahler, A.C.; Kawano, T.; Little, R.C.; Yount, P.G.

2011-01-01

The cross section covariance library has been under development by BNL-LANL collaborative effort over the last three years. The project builds on two covariance libraries developed earlier, with considerable input from BNL and LANL. In 2006, international effort under WPEC Subgroup 26 produced BOLNA covariance library by putting together data, often preliminary, from various sources for most important materials for nuclear reactor technology. This was followed in 2007 by collaborative effort of four US national laboratories to produce covariances, often of modest quality - hence the name low-fidelity, for virtually complete set of materials included in ENDF/B-VII.0. The present project is focusing on covariances of 4-5 major reaction channels for 110 materials of importance for power reactors. The work started under Global Nuclear Energy Partnership (GNEP) in 2008, which changed to Advanced Fuel Cycle Initiative (AFCI) in 2009. With the 2011 release the name has changed to the Covariance Multigroup Matrix for Advanced Reactor Applications (COMMARA) version 2.0. The primary purpose of the library is to provide covariances for AFCI data adjustment project, which is focusing on the needs of fast advanced burner reactors. Responsibility of BNL was defined as developing covariances for structural materials and fission products, management of the library and coordination of the work; LANL responsibility was defined as covariances for light nuclei and actinides. The COMMARA-2.0 covariance library has been developed by BNL-LANL collaboration for Advanced Fuel Cycle Initiative applications over the period of three years, 2008-2010. It contains covariances for 110 materials relevant to fast reactor R and D. The library is to be used together with the ENDF/B-VII.0 central values of the latest official release of US files of evaluated neutron cross sections. COMMARA-2.0 library contains neutron cross section covariances for 12 light nuclei (coolants and moderators), 78

Prevalence of subretinal drusenoid deposits in older persons with and without age-related macular degeneration, by multimodal imaging

Science.gov (United States)

Zarubina, Anna V.; Neely, David C.; Clark, Mark E.; Huisingh, Carrie E.; Samuels, Brian C.; Zhang, Yuhua; McGwin, Gerald; Owsley, Cynthia; Curcio, Christine A.

2015-01-01

Purpose To assess the prevalence of subretinal drusenoid deposits (SDD) in older adults with healthy maculas and early and intermediate age-related macular degeneration (AMD) using multimodal imaging. Design Cross-sectional study. Participants A total of 651 subjects aged ≥60 years enrolled in the Alabama Study of Early Age-Related Macular Degeneration from primary care ophthalmology clinics. Methods Subjects were imaged using spectral domain optical coherence tomography (SD-OCT) of the macula and optic nerve head (ONH), infrared reflectance, fundus autofluorescence, and color fundus photographs (CFP). Eyes were assessed for AMD presence and severity using the AREDS 9-step scale. Criteria for SDD presence were identification on ≥1 en-face modality plus SD-OCT or on ≥2 en-face modalities if absent on SD-OCT. SDD were considered present at the person-level if present in 1 or both eyes. Main outcomes measures Prevalence of SDD in participants with and without AMD. Results Overall prevalence of SDD was 32% (197/611), with 62% (122/197) affected in both eyes. Persons with SDD were older than those without SDD (70.6 vs. 68.7 years, p =0.0002). Prevalence of SDD was 23% in subjects without AMD and 52% in subjects with AMD (pmaculae and in more than half of persons with early to intermediate AMD, even by stringent criteria. The prevalence of SDD is strongly associated with AMD presence and severity and increases with age, and its retinal topography including peripapillary involvement resembles that of rod photoreceptors. Consensus on SDD detection methods is recommended to advance our knowledge of this lesion and its clinical and biologic significance. PMID:26875000

Prevalence of uncorrected refractive errors in adults aged 30 years and above in a rural population in Pakistan

International Nuclear Information System (INIS)

Abdullah, A.S.; Azam, M.; Nigar, M.

2015-01-01

Uncorrected refractive errors are a leading cause of visual disability globally. This population-based study was done to estimate the prevalence of uncorrected refractive errors in adults aged 30 years and above of village Pawakah, Khyber Pakhtunkhwa (KPK), Pakistan. Methods: It was a cross-sectional survey in which 1000 individuals were included randomly. All the individuals were screened for uncorrected refractive errors and those whose visual acuity (VA) was found to be less than 6/6 were refracted. In whom refraction was found to be unsatisfactory (i.e., a best corrected visual acuity of <6/6) further examination was done to establish the cause for the subnormal vision. Results: A total of 917 subjects participated in the survey (response rate 92%). The prevalence of uncorrected refractive errors was found to be 23.97% among males and 20% among females. The prevalence of visually disabling refractive errors was 6.89% in males and 5.71% in females. The prevalence was seen to increase with age, with maximum prevalence in 51-60 years age group. Hypermetropia (10.14%) was found to be the commonest refractive error followed by Myopia (6.00%) and Astigmatism (5.6%). The prevalence of Presbyopia was 57.5% (60.45% in males and 55.23% in females). Poor affordability was the commonest barrier to the use of spectacles, followed by unawareness. Cataract was the commonest reason for impaired vision after refractive correction. The prevalence of blindness was 1.96% (1.53% in males and 2.28% in females) in this community with cataract as the commonest cause. Conclusions: Despite being the most easily avoidable cause of subnormal vision uncorrected refractive errors still account for a major proportion of the burden of decreased vision in this area. Effective measures for the screening and affordable correction of uncorrected refractive errors need to be incorporated into the health care delivery system. (author)

Experience in using the covariances of some ENDF/B-V dosimetry cross sections: proposed improvements and addition of cross-reaction covariances

International Nuclear Information System (INIS)

Fu, C.Y.; Hetrick, D.M.

1982-01-01

Recent ratio data, with carefully evaluated covariances, were combined with eleven of the ENDF/B-V dosimetry cross sections using the generalized least-squares method. The purpose was to improve these evaluated cross sections and covariances, as well as to generate values for the cross-reaction covariances. The results represent improved cross sections as well as realistic and usable covariances. The latter are necessary for meaningful intergral-differential comparisons and for spectrum unfolding

High-dimensional covariance estimation with high-dimensional data

CERN Document Server

Pourahmadi, Mohsen

2013-01-01

Methods for estimating sparse and large covariance matrices Covariance and correlation matrices play fundamental roles in every aspect of the analysis of multivariate data collected from a variety of fields including business and economics, health care, engineering, and environmental and physical sciences. High-Dimensional Covariance Estimation provides accessible and comprehensive coverage of the classical and modern approaches for estimating covariance matrices as well as their applications to the rapidly developing areas lying at the intersection of statistics and mac

Morphological covariance in anatomical MRI scans can identify discrete neural pathways in the brain and their disturbances in persons with neuropsychiatric disorders.

Science.gov (United States)

Bansal, Ravi; Hao, Xuejun; Peterson, Bradley S

2015-05-01

We hypothesize that coordinated functional activity within discrete neural circuits induces morphological organization and plasticity within those circuits. Identifying regions of morphological covariation that are independent of morphological covariation in other regions therefore may therefore allow us to identify discrete neural systems within the brain. Comparing the magnitude of these variations in individuals who have psychiatric disorders with the magnitude of variations in healthy controls may allow us to identify aberrant neural pathways in psychiatric illnesses. We measured surface morphological features by applying nonlinear, high-dimensional warping algorithms to manually defined brain regions. We transferred those measures onto the surface of a unit sphere via conformal mapping and then used spherical wavelets and their scaling coefficients to simplify the data structure representing these surface morphological features of each brain region. We used principal component analysis (PCA) to calculate covariation in these morphological measures, as represented by their scaling coefficients, across several brain regions. We then assessed whether brain subregions that covaried in morphology, as identified by large eigenvalues in the PCA, identified specific neural pathways of the brain. To do so, we spatially registered the subnuclei for each eigenvector into the coordinate space of a Diffusion Tensor Imaging dataset; we used these subnuclei as seed regions to track and compare fiber pathways with known fiber pathways identified in neuroanatomical atlases. We applied these procedures to anatomical MRI data in a cohort of 82 healthy participants (42 children, 18 males, age 10.5 ± 2.43 years; 40 adults, 22 males, age 32.42 ± 10.7 years) and 107 participants with Tourette's Syndrome (TS) (71 children, 59 males, age 11.19 ± 2.2 years; 36 adults, 21 males, age 37.34 ± 10.9 years). We evaluated the construct validity of the identified covariation in morphology

Age-wise and gender-wise prevalence of oral habits in 7–16-year-old school children of Mewar ethnicity, India

Directory of Open Access Journals (Sweden)

Pradeep Vishnoi

2017-01-01

Full Text Available Objectives: The study aimed to check the age- and gender-wise prevalence of oral habits in the children of 7–16-year-old Indian children. Materials and Methods: A cross-sectional survey involving 1029 (661 males and 368 females children of age 7–16 years was done to record the presence or absence of the oral habits with the aid of the anamnestic questionnaire. The recorded oral habits were tongue thrusting, thumb or digit sucking, mouth breathing, bruxism, lip biting or lip sucking, and nail biting. The collected data were subjected to Pearson's Chi-square statistical analysis to know the overall difference in the prevalence rate of different oral habits and to evaluate the gender- and age-wise difference in the prevalence of oral habits. Results: Oral habits were present in 594 participants (57.73%. The highest prevalence rate was registered for tongue thrusting habit (28.8%, which was followed by nail biting (201/19.5% and thumb sucking (128/12.4%, mouth breathing (109/10.6%, lip biting (85/8.3%, and bruxism (29/2.8%. The male participants showed a greater prevalence rate for the oral habits than the female participants (58.55% vs. 56.25%. There was a significant difference in the age-wise prevalence of oral habits with older children showing greater prevalence of oral habits than the younger ones. Conclusion: The prevalence of oral habits in the current group of children is high. It warrants the need for the community-based educational preventive and interceptive programs to spread the awareness regarding the deleterious effects of these oral habits.

Prevalence and Determinants of Glaucoma in Citizens of Qatar Aged 40 Years or Older: A Community-Based Survey

Science.gov (United States)

Al-Mansouri, Fatma A.; Kanaan, Aida; Gamra, Hamad; Khandekar, Rajiv; Hashim, Shakeel P.; Al Qahtani, Omar; Ahmed, Mohd. Farouk

2011-01-01

Background: We present the prevalence and determinants of glaucoma among subjects 40 years of age and older in Qatar. Materials and Methods: This community-based survey was held in 2009 at 49 randomly selected clusters. Demographic details and history of glaucoma was collected by the nurses. Ophthalmologists evaluated the optic disc and retina using a digital camera housed in a mobile van. Visual field was tested with an automated perimeter, the intraocular pressure with an applanation tonometer and the angle of the anterior chamber by gonioscopy. A panel of glaucoma experts diagnosed subjects with glaucoma. Results: This survey enrolled 3,149 (97.3%) participants. The age- and sex-adjusted prevalence of glaucoma in the population aged 40 years and older was 1.73% (95% confidence intervals [CI] 1.69-1.77). Accordingly, 5,641 individuals in this age group in Qatar would have glaucoma. Chronological age of 60 years and older (Odds ratio [OR] 11.1) and the presence of myopia (OR 1.78) were predictors of glaucoma. Open-angle glaucoma was diagnosed in 44 (65.7%) individuals with glaucoma. In nine (13.4%) and 15 (20.9%) subjects, angle closure glaucoma and other (post-traumatic, pseudoexfoliation) glaucoma were present. Bilateral blindness (vision glaucoma, respectively. Glaucoma was treated in 36 (54%) subjects. Conclusions: The prevalence of glaucoma among citizens of Qatar aged 40 years and older was 1.71%. Glaucoma was associated with the age of 60 years and older and the presence of myopia. PMID:21731325

Prediction of community prevalence of human onchocerciasis in the Amazonian onchocerciasis focus: Bayesian approach.

Science.gov (United States)

Carabin, Hélène; Escalona, Marisela; Marshall, Clare; Vivas-Martínez, Sarai; Botto, Carlos; Joseph, Lawrence; Basáñez, María-Gloria

2003-01-01

To develop a Bayesian hierarchical model for human onchocerciasis with which to explore the factors that influence prevalence of microfilariae in the Amazonian focus of onchocerciasis and predict the probability of any community being at least mesoendemic (>20% prevalence of microfilariae), and thus in need of priority ivermectin treatment. Models were developed with data from 732 individuals aged > or =15 years who lived in 29 Yanomami communities along four rivers of the south Venezuelan Orinoco basin. The models' abilities to predict prevalences of microfilariae in communities were compared. The deviance information criterion, Bayesian P-values, and residual values were used to select the best model with an approximate cross-validation procedure. A three-level model that acknowledged clustering of infection within communities performed best, with host age and sex included at the individual level, a river-dependent altitude effect at the community level, and additional clustering of communities along rivers. This model correctly classified 25/29 (86%) villages with respect to their need for priority ivermectin treatment. Bayesian methods are a flexible and useful approach for public health research and control planning. Our model acknowledges the clustering of infection within communities, allows investigation of links between individual- or community-specific characteristics and infection, incorporates additional uncertainty due to missing covariate data, and informs policy decisions by predicting the probability that a new community is at least mesoendemic.

Covariance problem in two-dimensional quantum chromodynamics

International Nuclear Information System (INIS)

Hagen, C.R.

1979-01-01

The problem of covariance in the field theory of a two-dimensional non-Abelian gauge field is considered. Since earlier work has shown that covariance fails (in charged sectors) for the Schwinger model, particular attention is given to an evaluation of the role played by the non-Abelian nature of the fields. In contrast to all earlier attempts at this problem, it is found that the potential covariance-breaking terms are identical to those found in the Abelian theory provided that one expresses them in terms of the total (i.e., conserved) current operator. The question of covariance is thus seen to reduce in all cases to a determination as to whether there exists a conserved global charge in the theory. Since the charge operator in the Schwinger model is conserved only in neutral sectors, one is thereby led to infer a probable failure of covariance in the non-Abelian theory, but one which is identical to that found for the U(1) case

Schroedinger covariance states in anisotropic waveguides

International Nuclear Information System (INIS)

Angelow, A.; Trifonov, D.

1995-03-01

In this paper Squeezed and Covariance States based on Schroedinger inequality and their connection with other nonclassical states are considered for particular case of anisotropic waveguide in LiNiO 3 . Here, the problem of photon creation and generation of squeezed and Schroedinger covariance states in optical waveguides is solved in two steps: 1. Quantization of electromagnetic field is provided in the presence of dielectric waveguide using normal-mode expansion. The photon creation and annihilation operators are introduced, expanding the solution A-vector(r-vector,t) in a series in terms of the Sturm - Liouville mode-functions. 2. In terms of these operators the Hamiltonian of the field in a nonlinear waveguide is derived. For such Hamiltonian we construct the covariance states as stable (with nonzero covariance), which minimize the Schroedinger uncertainty relation. The evolutions of the three second momenta of q-circumflex j and p-circumflex j are calculated. For this Hamiltonian all three momenta are expressed in terms of one real parameters s only. It is found out how covariance, via this parameter s, depends on the waveguide profile n(x,y), on the mode-distributions u-vector j (x,y), and on the waveguide phase mismatching Δβ. (author). 37 refs

Form of the manifestly covariant Lagrangian

Science.gov (United States)

Johns, Oliver Davis

1985-10-01

The preferred form for the manifestly covariant Lagrangian function of a single, charged particle in a given electromagnetic field is the subject of some disagreement in the textbooks. Some authors use a ``homogeneous'' Lagrangian and others use a ``modified'' form in which the covariant Hamiltonian function is made to be nonzero. We argue in favor of the ``homogeneous'' form. We show that the covariant Lagrangian theories can be understood only if one is careful to distinguish quantities evaluated on the varied (in the sense of the calculus of variations) world lines from quantities evaluated on the unvaried world lines. By making this distinction, we are able to derive the Hamilton-Jacobi and Klein-Gordon equations from the ``homogeneous'' Lagrangian, even though the covariant Hamiltonian function is identically zero on all world lines. The derivation of the Klein-Gordon equation in particular gives Lagrangian theoretical support to the derivations found in standard quantum texts, and is also shown to be consistent with the Feynman path-integral method. We conclude that the ``homogeneous'' Lagrangian is a completely adequate basis for covariant Lagrangian theory both in classical and quantum mechanics. The article also explores the analogy with the Fermat theorem of optics, and illustrates a simple invariant notation for the Lagrangian and other four-vector equations.

Convex Banding of the Covariance Matrix.

Science.gov (United States)

Bien, Jacob; Bunea, Florentina; Xiao, Luo

2016-01-01

We introduce a new sparse estimator of the covariance matrix for high-dimensional models in which the variables have a known ordering. Our estimator, which is the solution to a convex optimization problem, is equivalently expressed as an estimator which tapers the sample covariance matrix by a Toeplitz, sparsely-banded, data-adaptive matrix. As a result of this adaptivity, the convex banding estimator enjoys theoretical optimality properties not attained by previous banding or tapered estimators. In particular, our convex banding estimator is minimax rate adaptive in Frobenius and operator norms, up to log factors, over commonly-studied classes of covariance matrices, and over more general classes. Furthermore, it correctly recovers the bandwidth when the true covariance is exactly banded. Our convex formulation admits a simple and efficient algorithm. Empirical studies demonstrate its practical effectiveness and illustrate that our exactly-banded estimator works well even when the true covariance matrix is only close to a banded matrix, confirming our theoretical results. Our method compares favorably with all existing methods, in terms of accuracy and speed. We illustrate the practical merits of the convex banding estimator by showing that it can be used to improve the performance of discriminant analysis for classifying sound recordings.

Determination of covariant Schwinger terms in anomalous gauge theories

International Nuclear Information System (INIS)

Kelnhofer, G.

1991-01-01

A functional integral method is used to determine equal time commutators between the covariant currents and the covariant Gauss-law operators in theories which are affected by an anomaly. By using a differential geometrical setup we show how the derivation of consistent- and covariant Schwinger terms can be understood on an equal footing. We find a modified consistency condition for the covariant anomaly. As a by-product the Bardeen-Zumino functional, which relates consistent and covariant anomalies, can be interpreted as connection on a certain line bundle over all gauge potentials. Finally the covariant commutator anomalies are calculated for the two- and four dimensional case. (orig.)

Prevalence and Pattern of Executive Dysfunction in School Age Children with Congenital Heart Disease

Science.gov (United States)

Sanz, Jacqueline H.; Berl, Madison M.; Armour, Anna C.; Wang, Jichuan; Cheng, Yao I.; Donofrio, Mary T.

2016-01-01

Objective Executive Function, a set of cognitive skills important to social and academic outcomes, is a specific area of cognitive weakness in children with congenital heart disease (CHD). We evaluated the prevalence and profile of executive dysfunction in a heterogeneous sample of school aged children with CHD, examined whether children with executive dysfunction are receiving school services and support, and identified risk factors for executive dysfunction at school age. Design 91 school aged patients completed questionnaires, including the Behavior Rating Inventory of Executive Function (BRIEF) and a medical history questionnaire. An age and gender matched control sample was drawn from a normativedatabase. Results CHD patients had a higher rate of parent reported executive dysfunction (OR=4.37, p0.05). Gender, premature birth (≤37 weeks), and CHD with aortic obstruction were predictive of executive dysfunction, especially for behavior regulation skills. Conclusions School aged children with CHD have an increased prevalence of executive dysfunction, especially problems with working memory and flexibility, and are underserved by the school system. The increased risk for executive dysfunction in those with CHD and prematurity or CHD with aortic obstruction suggests an etiology of delayed brain development in the fetal and neonatal periods, while male gender may increase susceptibility to brain injury. This study highlights the need for regular neurodevelopmental follow up in children with CHD, and a need to better understand mechanisms that contribute to adverse neurodevelopmental outcomes. PMID:27863079

Prevalence and pattern of executive dysfunction in school age children with congenital heart disease.

Science.gov (United States)

Sanz, Jacqueline H; Berl, Madison M; Armour, Anna C; Wang, Jichuan; Cheng, Yao I; Donofrio, Mary T

2017-03-01

Executive function, a set of cognitive skills important to social and academic outcomes, is a specific area of cognitive weakness in children with congenital heart disease (CHD). We evaluated the prevalence and profile of executive dysfunction in a heterogeneous sample of school aged children with CHD, examined whether children with executive dysfunction are receiving school services and support, and identified risk factors for executive dysfunction at school age. Ninety-one school aged patients completed questionnaires, including the Behavior Rating Inventory of Executive Function (BRIEF) and a medical history questionnaire. An age- and gender- matched control sample was drawn from a normative database. Children with CHD had a higher rate of parent reported executive dysfunction (OR = 4.37, P  .05). Gender, premature birth (≤37 weeks), and CHD with aortic obstruction were predictive of executive dysfunction, especially for behavior regulation skills. School aged children with CHD have an increased prevalence of executive dysfunction, especially problems with working memory and flexibility, and are underserved by the school system. The increased risk for executive dysfunction in those with CHD and prematurity or CHD with aortic obstruction suggests an etiology of delayed brain development in the fetal and neonatal periods, while male gender may increase susceptibility to brain injury. This study highlights the need for regular neurodevelopmental follow up in children with CHD, and a need to better understand mechanisms that contribute to adverse neurodevelopmental outcomes. © 2016 Wiley Periodicals, Inc.

Cross-population myelination covariance of human cerebral cortex.

Science.gov (United States)

Ma, Zhiwei; Zhang, Nanyin

2017-09-01

Cross-population covariance of brain morphometric quantities provides a measure of interareal connectivity, as it is believed to be determined by the coordinated neurodevelopment of connected brain regions. Although useful, structural covariance analysis predominantly employed bulky morphological measures with mixed compartments, whereas studies of the structural covariance of any specific subdivisions such as myelin are rare. Characterizing myelination covariance is of interest, as it will reveal connectivity patterns determined by coordinated development of myeloarchitecture between brain regions. Using myelin content MRI maps from the Human Connectome Project, here we showed that the cortical myelination covariance was highly reproducible, and exhibited a brain organization similar to that previously revealed by other connectivity measures. Additionally, the myelination covariance network shared common topological features of human brain networks such as small-worldness. Furthermore, we found that the correlation between myelination covariance and resting-state functional connectivity (RSFC) was uniform within each resting-state network (RSN), but could considerably vary across RSNs. Interestingly, this myelination covariance-RSFC correlation was appreciably stronger in sensory and motor networks than cognitive and polymodal association networks, possibly due to their different circuitry structures. This study has established a new brain connectivity measure specifically related to axons, and this measure can be valuable to investigating coordinated myeloarchitecture development. Hum Brain Mapp 38:4730-4743, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Covariant extensions and the nonsymmetric unified field

International Nuclear Information System (INIS)

Borchsenius, K.

1976-01-01

The problem of generally covariant extension of Lorentz invariant field equations, by means of covariant derivatives extracted from the nonsymmetric unified field, is considered. It is shown that the contracted curvature tensor can be expressed in terms of a covariant gauge derivative which contains the gauge derivative corresponding to minimal coupling, if the universal constant p, characterizing the nonsymmetric theory, is fixed in terms of Planck's constant and the elementary quantum of charge. By this choice the spinor representation of the linear connection becomes closely related to the spinor affinity used by Infeld and Van Der Waerden (Sitzungsber. Preuss. Akad. Wiss. Phys. Math. Kl.; 9:380 (1933)) in their generally covariant formulation of Dirac's equation. (author)

Age and Sex Variation In Prevalence Of Chronic Medical Conditions In Older Residents of U.S. Nursing Homes

Science.gov (United States)

Moore, Kelly L.; Boscardin, W. John; Steinman, Michael A.; Schwartz, Janice B.

2012-01-01

OBJECTIVES To investigate patterns in prevalences of chronic medical conditions over the agespan of long-term stay nursing home residents and between the sexes with data from the 2004 National Nursing Home Survey (NNHS). DESIGN Retrospective, cross-sectional study. SETTING U.S. nursing homes. PARTICIPANTS Nationally representative sample comprising 11,788 long-term stay residents (3003 (25%) men and 8785 women) aged 65 years or older. MEASUREMENTS Clinical Classifications Software (CCS) was used to group ICD-9 codes to identify the 20 most prevalent chronic medical conditions. SAS survey procedures were used to account for design effects of stratification and clustering to generate nationally representative estimates of prevalences of medical conditions. RESULTS Average age was 84 y, with women older than men (85 vs. 81, p=0.02) with 67% of women ages 80–95. Women required more ADL assistance. The most frequent chronic medical conditions were hypertension (53, 56%: men, women), dementia (45, 52%), depression (31, 37%), arthritis (26, 35%), diabetes mellitus (26, 23%), gastrointestinal reflux -GERD (23, 23%), atherosclerosis (24, 20%), congestive heart failure -CHF (18, 21%), cerebrovascular disease (24, 19%) and anemia (17, 20%). Sex differences in prevalences existed for all but constipation, GERD, and hypertension. Diabetes, cerebrovascular disease, and lipid disorders decreased with age in men and women. Atrial fibrillation, anemia, arthritis, CHF, and dementia, and thyroid disease increased with age in both men and women. Age-related patterns differed between the sexes for diabetes, hypertension, and Parkinson’s disease. CONCLUSION The profile of chronic medical conditions varies over the agespan of nursing home residents and differs between men and women. This knowledge should guide educational and care efforts in long-term care. PMID:22463062

Computing more proper covariances of energy dependent nuclear data

International Nuclear Information System (INIS)

Vanhanen, R.

2016-01-01

Highlights: • We present conditions for covariances of energy dependent nuclear data to be proper. • We provide methods to detect non-positive and inconsistent covariances in ENDF-6 format. • We propose methods to find nearby more proper covariances. • The methods can be used as a part of a quality assurance program. - Abstract: We present conditions for covariances of energy dependent nuclear data to be proper in the sense that the covariances are positive, i.e., its eigenvalues are non-negative, and consistent with respect to the sum rules of nuclear data. For the ENDF-6 format covariances we present methods to detect non-positive and inconsistent covariances. These methods would be useful as a part of a quality assurance program. We also propose methods that can be used to find nearby more proper energy dependent covariances. These methods can be used to remove unphysical components, while preserving most of the physical components. We consider several different senses in which the nearness can be measured. These methods could be useful if a re-evaluation of improper covariances is not feasible. Two practical examples are processed and analyzed. These demonstrate some of the properties of the methods. We also demonstrate that the ENDF-6 format covariances of linearly dependent nuclear data should usually be encoded with the derivation rules.

The prevalence of food allergy and other allergic diseases in early childhood in a population-based study: HealthNuts age 4-year follow-up.

Science.gov (United States)

Peters, Rachel L; Koplin, Jennifer J; Gurrin, Lyle C; Dharmage, Shyamali C; Wake, Melissa; Ponsonby, Anne-Louise; Tang, Mimi L K; Lowe, Adrian J; Matheson, Melanie; Dwyer, Terence; Allen, Katrina J

2017-07-01

The HealthNuts study previously reported interim prevalence data showing the highest prevalence of challenge-confirmed food allergy in infants internationally. However, population-derived prevalence data on challenge-confirmed food allergy and other allergic diseases in preschool-aged children remain sparse. This study aimed to report the updated prevalence of food allergy at age 1 year from the whole cohort, and to report the prevalence of food allergy, asthma, eczema, and allergic rhinitis at age 4 years. HealthNuts is a population-based cohort study with baseline recruitment of 5276 one-year-old children who underwent skin prick test (SPT) to 4 food allergens and those with detectable SPT results had formal food challenges. At age 4 years, parents completed a questionnaire (81.3% completed) and those who previously attended the HealthNuts clinic at age 1 year or reported symptoms of a new food allergy were invited for an assessment that included SPT and oral food challenges. Data on asthma, eczema, and allergic rhinitis were captured by validated International Study of Asthma and Allergies in Childhood questionnaires. The prevalence of challenge-confirmed food allergy at age 1 and 4 years was 11.0% and 3.8%, respectively. At age 4 years, peanut allergy prevalence was 1.9% (95% CI, 1.6% to 2.3%), egg allergy was 1.2% (95% CI, 0.9% to 1.6%), and sesame allergy was 0.4% (95% CI, 0.3% to 0.6%). Late-onset peanut allergy at age 4 years was rare (0.2%). The prevalence of current asthma was 10.8% (95% CI, 9.7% to 12.1%), current eczema was 16.0% (95% CI, 14.7% to 17.4%), and current allergic rhinitis was 8.3% (95% CI, 7.2% to 9.4%). Forty percent to 50% of this population-based cohort experienced symptoms of an allergic disease in the first 4 years of their life. Although the prevalence of food allergy decreased between age 1 year and age 4 years in this population-based cohort, the prevalence of any allergic disease among 4-year-old children in Melbourne

Covariance Spectroscopy for Fissile Material Detection

International Nuclear Information System (INIS)

Trainham, Rusty; Tinsley, Jim; Hurley, Paul; Keegan, Ray

2009-01-01

Nuclear fission produces multiple prompt neutrons and gammas at each fission event. The resulting daughter nuclei continue to emit delayed radiation as neutrons boil off, beta decay occurs, etc. All of the radiations are causally connected, and therefore correlated. The correlations are generally positive, but when different decay channels compete, so that some radiations tend to exclude others, negative correlations could also be observed. A similar problem of reduced complexity is that of cascades radiation, whereby a simple radioactive decay produces two or more correlated gamma rays at each decay. Covariance is the usual means for measuring correlation, and techniques of covariance mapping may be useful to produce distinct signatures of special nuclear materials (SNM). A covariance measurement can also be used to filter data streams because uncorrelated signals are largely rejected. The technique is generally more effective than a coincidence measurement. In this poster, we concentrate on cascades and the covariance filtering problem

Optimal covariate designs theory and applications

CERN Document Server

Das, Premadhis; Mandal, Nripes Kumar; Sinha, Bikas Kumar

2015-01-01

This book primarily addresses the optimality aspects of covariate designs. A covariate model is a combination of ANOVA and regression models. Optimal estimation of the parameters of the model using a suitable choice of designs is of great importance; as such choices allow experimenters to extract maximum information for the unknown model parameters. The main emphasis of this monograph is to start with an assumed covariate model in combination with some standard ANOVA set-ups such as CRD, RBD, BIBD, GDD, BTIBD, BPEBD, cross-over, multi-factor, split-plot and strip-plot designs, treatment control designs, etc. and discuss the nature and availability of optimal covariate designs. In some situations, optimal estimations of both ANOVA and the regression parameters are provided. Global optimality and D-optimality criteria are mainly used in selecting the design. The standard optimality results of both discrete and continuous set-ups have been adapted, and several novel combinatorial techniques have been applied for...

Covariate Imbalance and Precision in Measuring Treatment Effects

Science.gov (United States)

Liu, Xiaofeng Steven

2011-01-01

Covariate adjustment can increase the precision of estimates by removing unexplained variance from the error in randomized experiments, although chance covariate imbalance tends to counteract the improvement in precision. The author develops an easy measure to examine chance covariate imbalance in randomization by standardizing the average…

Covariant description of Hamiltonian form for field dynamics

International Nuclear Information System (INIS)

Ozaki, Hiroshi

2005-01-01

Hamiltonian form of field dynamics is developed on a space-like hypersurface in space-time. A covariant Poisson bracket on the space-like hypersurface is defined and it plays a key role to describe every algebraic relation into a covariant form. It is shown that the Poisson bracket has the same symplectic structure that was brought in the covariant symplectic approach. An identity invariant under the canonical transformations is obtained. The identity follows a canonical equation in which the interaction Hamiltonian density generates a deformation of the space-like hypersurface. The equation just corresponds to the Yang-Feldman equation in the Heisenberg pictures in quantum field theory. By converting the covariant Poisson bracket on the space-like hypersurface to four-dimensional commutator, we can pass over to quantum field theory in the Heisenberg picture without spoiling the explicit relativistic covariance. As an example the canonical QCD is displayed in a covariant way on a space-like hypersurface

Dimension from covariance matrices.

Science.gov (United States)

Carroll, T L; Byers, J M

2017-02-01

We describe a method to estimate embedding dimension from a time series. This method includes an estimate of the probability that the dimension estimate is valid. Such validity estimates are not common in algorithms for calculating the properties of dynamical systems. The algorithm described here compares the eigenvalues of covariance matrices created from an embedded signal to the eigenvalues for a covariance matrix of a Gaussian random process with the same dimension and number of points. A statistical test gives the probability that the eigenvalues for the embedded signal did not come from the Gaussian random process.

Structural covariance of neostriatal and limbic regions in patients with obsessive-compulsive disorder.

Science.gov (United States)

Subirà, Marta; Cano, Marta; de Wit, Stella J; Alonso, Pino; Cardoner, Narcís; Hoexter, Marcelo Q; Kwon, Jun Soo; Nakamae, Takashi; Lochner, Christine; Sato, João R; Jung, Wi Hoon; Narumoto, Jin; Stein, Dan J; Pujol, Jesus; Mataix-Cols, David; Veltman, Dick J; Menchón, José M; van den Heuvel, Odile A; Soriano-Mas, Carles

2016-03-01

Frontostriatal and frontoamygdalar connectivity alterations in patients with obsessive-compulsive disorder (OCD) have been typically described in functional neuroimaging studies. However, structural covariance, or volumetric correlations across distant brain regions, also provides network-level information. Altered structural covariance has been described in patients with different psychiatric disorders, including OCD, but to our knowledge, alterations within frontostriatal and frontoamygdalar circuits have not been explored. We performed a mega-analysis pooling structural MRI scans from the Obsessive-compulsive Brain Imaging Consortium and assessed whole-brain voxel-wise structural covariance of 4 striatal regions (dorsal and ventral caudate nucleus, and dorsal-caudal and ventral-rostral putamen) and 2 amygdalar nuclei (basolateral and centromedial-superficial). Images were preprocessed with the standard pipeline of voxel-based morphometry studies using Statistical Parametric Mapping software. Our analyses involved 329 patients with OCD and 316 healthy controls. Patients showed increased structural covariance between the left ventral-rostral putamen and the left inferior frontal gyrus/frontal operculum region. This finding had a significant interaction with age; the association held only in the subgroup of older participants. Patients with OCD also showed increased structural covariance between the right centromedial-superficial amygdala and the ventromedial prefrontal cortex. This was a cross-sectional study. Because this is a multisite data set analysis, participant recruitment and image acquisition were performed in different centres. Most patients were taking medication, and treatment protocols differed across centres. Our results provide evidence for structural network-level alterations in patients with OCD involving 2 frontosubcortical circuits of relevance for the disorder and indicate that structural covariance contributes to fully characterizing brain

Prevalence and factors associated with stunting and excess weight in children aged 0-5 years from the Brazilian semi-arid region.

Science.gov (United States)

Ramos, Clariana V; Dumith, Samuel C; César, Juraci A

2015-01-01

To analyze the prevalence of excess weight and low height, and identify associated factors among children younger than five years. Cross-census study. A total of 1,640 children from two municipalities in Piauí, Brazil were included. The prevalence of low height was 10.9% (95% CI: 9.3 to 12.4), inversely associated with mother's younger age and low level of education, lower socioeconomic status, mothers who had fewer than six prenatal consultations, and households that had more than one child younger than 5 years. Excess weight prevalence was 19.1% (95% CI: 17.2 to 21.0), and remained inversely associated with lower maternal age, low maternal education, and cesarean delivery. Stunting was greater in children aged between 12 and 23 months, while excess weight decreased with age. It is noteworthy that the stunting rate, although decreasing, is still high, while the prevalence of excess weight, even in this very poor area, already exceeds the expected percentage for a population with better socioeconomic level. Copyright © 2014 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

ANL Critical Assembly Covariance Matrix Generation - Addendum

Energy Technology Data Exchange (ETDEWEB)

McKnight, Richard D. [Argonne National Lab. (ANL), Argonne, IL (United States); Grimm, Karl N. [Argonne National Lab. (ANL), Argonne, IL (United States)

2014-01-13

In March 2012, a report was issued on covariance matrices for Argonne National Laboratory (ANL) critical experiments. That report detailed the theory behind the calculation of covariance matrices and the methodology used to determine the matrices for a set of 33 ANL experimental set-ups. Since that time, three new experiments have been evaluated and approved. This report essentially updates the previous report by adding in these new experiments to the preceding covariance matrix structure.

Condition Number Regularized Covariance Estimation.

Science.gov (United States)

Won, Joong-Ho; Lim, Johan; Kim, Seung-Jean; Rajaratnam, Bala

2013-06-01

Estimation of high-dimensional covariance matrices is known to be a difficult problem, has many applications, and is of current interest to the larger statistics community. In many applications including so-called the "large p small n " setting, the estimate of the covariance matrix is required to be not only invertible, but also well-conditioned. Although many regularization schemes attempt to do this, none of them address the ill-conditioning problem directly. In this paper, we propose a maximum likelihood approach, with the direct goal of obtaining a well-conditioned estimator. No sparsity assumption on either the covariance matrix or its inverse are are imposed, thus making our procedure more widely applicable. We demonstrate that the proposed regularization scheme is computationally efficient, yields a type of Steinian shrinkage estimator, and has a natural Bayesian interpretation. We investigate the theoretical properties of the regularized covariance estimator comprehensively, including its regularization path, and proceed to develop an approach that adaptively determines the level of regularization that is required. Finally, we demonstrate the performance of the regularized estimator in decision-theoretic comparisons and in the financial portfolio optimization setting. The proposed approach has desirable properties, and can serve as a competitive procedure, especially when the sample size is small and when a well-conditioned estimator is required.

Prevalence of Perceived Dysphonia and Its Correlation With the Prevalence of Clinically Diagnosed Laryngeal Disorders: The Korea National Health and Nutrition Examination Surveys 2010-2012.

Science.gov (United States)

Byeon, Haewon

2015-10-01

This study investigated the prevalence of perceived dysphonia and its correlation with the prevalence of clinically diagnosed laryngeal disorders. Subjects were 8713 non-institutionalized civilian adults over the age of 19 (3810 men and 4912 women) who completed the laryngeal examination of the fifth Korea National Health and Nutrition Examination Survey. A Poisson regression was used to examine the association between perceived dysphonia and laryngeal disorders. Adjusting for covariates (age, sex, education level, income, occupation, alcohol drinking, and self-reported health status), those with perceived voice problems were 4.8 times (OR=4.75, 95% CI, 3.77-5.99) more likely to have laryngeal disorders than those without voice problems. In particular, the vocal fold pathology correlated with perceived dysphonia was: vocal fold nodules (OR=5.32, 95% CI, 3.43-8.26), vocal polyps (OR=3.73, 95% CI, 1.57-8.86), vocal cysts (OR=11.97, 95% CI, 1.97-72.72), Reinke's edema (OR=9.27, 95% CI, 4.77-18.00), laryngeal paralysis (OR=3.58, 95% CI, 1.56-8.26), laryngeal granulomas (OR=4.31, 95% CI, 1.01-18.80), epiglottic cyst (OR=2.94, 95% CI, 1.21-7.13), and laryngitis (OR=4.07, 95% CI, 2.91-5.69). People with self-perceived dysphonia had a high risk of laryngeal disorders. © The Author(s) 2015.

Relationship of age and gender to the prevalence and correlates of psychological distress in later life.

Science.gov (United States)

Byles, Julie E; Gallienne, Lucy; Blyth, Fiona M; Banks, Emily

2012-06-01

As populations age, psychological distress in late life will become of increasing public health and social importance. This study seeks to bridge the gap in information that exists about psychological distress in late life, by exploring the prevalence of psychological distress among a very large sample of older adults to determine the impact of age and gender, and the modifying effect of these factors on the associations between measures of psychological distress and sociodemographic and comorbid conditions. We analyzed self-reported data from 236,508 men and women in the New South Wales 45 and Up Study, to determine the impact of age and gender, and the modifying effects of these factors on associations between psychological distress and sociodemographic and comorbid conditions. Higher education, married status, and higher income were associated with lower risk of psychological distress. Although overall prevalence of psychological distress is lower at older ages, this increases after age 80, and is particularly associated with physical disabilities. Some older people (such as those requiring help because of disability and those with multiple comorbid health conditions) are at increased risk of psychological distress. These findings have implications for both healthcare providers and policy-makers in identifying and responding to the needs of older people in our aging society.

Prevalence of dental fluorosis in children taking part in an oral health programme including fluoride tablet supplements from the age of 2 years

DEFF Research Database (Denmark)

Eckersten, Charlotte; Pylvänen, Lena; Schröder, Ulla

2010-01-01

To investigate the prevalence of dental fluorosis in children who had participated in an oral health programme between the ages 2-5 years, including fluoride tablets from the age of 2 years.......To investigate the prevalence of dental fluorosis in children who had participated in an oral health programme between the ages 2-5 years, including fluoride tablets from the age of 2 years....

Atrophy and structural covariance of the cholinergic basal forebrain in primary progressive aphasia.

Science.gov (United States)

Teipel, Stefan; Raiser, Theresa; Riedl, Lina; Riederer, Isabelle; Schroeter, Matthias L; Bisenius, Sandrine; Schneider, Anja; Kornhuber, Johannes; Fliessbach, Klaus; Spottke, Annika; Grothe, Michel J; Prudlo, Johannes; Kassubek, Jan; Ludolph, Albert; Landwehrmeyer, Bernhard; Straub, Sarah; Otto, Markus; Danek, Adrian

2016-10-01

Primary progressive aphasia (PPA) is characterized by profound destruction of cortical language areas. Anatomical studies suggest an involvement of cholinergic basal forebrain (BF) in PPA syndromes, particularly in the area of the nucleus subputaminalis (NSP). Here we aimed to determine the pattern of atrophy and structural covariance as a proxy of structural connectivity of BF nuclei in PPA variants. We studied 62 prospectively recruited cases with the clinical diagnosis of PPA and 31 healthy older control participants from the cohort study of the German consortium for frontotemporal lobar degeneration (FTLD). We determined cortical and BF atrophy based on high-resolution magnetic resonance imaging (MRI) scans. Patterns of structural covariance of BF with cortical regions were determined using voxel-based partial least square analysis. We found significant atrophy of total BF and BF subregions in PPA patients compared with controls [F(1, 82) = 20.2, p covariance analysis in healthy controls revealed associations of the BF nuclei, particularly the NSP, with left hemispheric predominant prefrontal, lateral temporal, and parietal cortical areas, including Broca's speech area (p covariance of the BF nuclei mostly with right but not with left hemispheric cortical areas (p covariance of the BF with left hemispheric cortical areas in healthy aging towards right hemispheric cortical areas in PPA, possibly reflecting a consequence of the profound and early destruction of cortical language areas in PPA. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Prevalence of the geriatric syndromes and frailty in older men living in the community: The Concord Health and Ageing in Men Project.

Science.gov (United States)

Noguchi, Naomi; Blyth, Fiona M; Waite, Louise M; Naganathan, Vasi; Cumming, Robert G; Handelsman, David J; Seibel, Markus J; Le Couteur, David G

2016-12-01

To describe the age at which the geriatric syndromes and frailty become common in community-dwelling men. The Concord Health and Ageing in Men Project involves a population-based sample of 1705 community-dwelling men aged 70 and over from a defined geographic region in Sydney. Data were obtained by physical performance tests, clinical examinations, and questionnaire to determine the prevalence of the following conditions by five-year age group. Poor mobility, recurrent falls, urinary incontinence, dementia and frailty phenotype were all uncommon (less than 10%) in men in their 70s, but the prevalence of each of these conditions exceeded 10% in men aged 85-89. The prevalence of Frailty Index-defined frailty, multimorbidity, polypharmacy and instrumental activities of daily living dependence was constantly high in all age groups. The different health-care needs of the 'old old' aged 85 years and older should be accounted for in health service planning. © 2016 AJA Inc.

Parametric Covariance Model for Horizon-Based Optical Navigation

Science.gov (United States)

Hikes, Jacob; Liounis, Andrew J.; Christian, John A.

2016-01-01

This Note presents an entirely parametric version of the covariance for horizon-based optical navigation measurements. The covariance can be written as a function of only the spacecraft position, two sensor design parameters, the illumination direction, the size of the observed planet, the size of the lit arc to be used, and the total number of observed horizon points. As a result, one may now more clearly understand the sensitivity of horizon-based optical navigation performance as a function of these key design parameters, which is insight that was obscured in previous (and nonparametric) versions of the covariance. Finally, the new parametric covariance is shown to agree with both the nonparametric analytic covariance and results from a Monte Carlo analysis.

Prevalence of Subretinal Drusenoid Deposits in Older Persons with and without Age-Related Macular Degeneration, by Multimodal Imaging.

Science.gov (United States)

Zarubina, Anna V; Neely, David C; Clark, Mark E; Huisingh, Carrie E; Samuels, Brian C; Zhang, Yuhua; McGwin, Gerald; Owsley, Cynthia; Curcio, Christine A

2016-05-01

To assess the prevalence of subretinal drusenoid deposits (SDD) in older adults with healthy maculas and early and intermediate age-related macular degeneration (AMD) using multimodal imaging. Cross-sectional study. A total of 651 subjects aged ≥60 years enrolled in the Alabama Study of Early Age-Related Macular Degeneration from primary care ophthalmology clinics. Subjects were imaged using spectral domain optical coherence tomography (SD OCT) of the macula and optic nerve head (ONH), infrared reflectance, fundus autofluorescence, and color fundus photographs (CFP). Eyes were assessed for AMD presence and severity using the Age-Related Eye Disease Study (AREDS) 9-step scale. Criteria for SDD presence were identification on ≥1 en face modality plus SD OCT or on ≥2 en face modalities if absent on SD OCT. Subretinal drusenoid deposits were considered present at the person level if present in 1 or both eyes. Prevalence of SDD in participants with and without AMD. Overall prevalence of SDD was 32% (197/611), with 62% (122/197) affected in both eyes. Persons with SDD were older than those without SDD (70.6 vs. 68.7 years, P = 0.0002). Prevalence of SDD was 23% in subjects without AMD and 52% in subjects with AMD (P maculae and in more than half of persons with early to intermediate AMD, even by stringent criteria. The prevalence of SDD is strongly associated with AMD presence and severity and increases with age, and its retinal topography including peripapillary involvement resembles that of rod photoreceptors. Consensus on SDD detection methods is recommended to advance our knowledge of this lesion and its clinical and biologic significance. Copyright © 2016 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

Scale-covariant theory of gravitation and astrophysical applications

International Nuclear Information System (INIS)

Canuto, V.; Adams, P.J.; Hsieh, S.; Tsiang, E.

1977-01-01

By associating the mathematical operation of scale transformation with the physics of using different dynamical systems to measure space-time distances, we formulate a scale-covariant theory of gravitation. Corresponding to each dynamical system of units is a gauge condition which determines the otherwise arbitrary gauge function. For gravitational units, the gauge condition is chosen so that the standard Einstein equations are recovered. Assuming the atomic units, derivable from atomic dynamics, to be distinct from the gravitational units, a different gauge condition must be imposed. It is suggested that Dirac's large-number hypothesis be used for the determination of this condition so that gravitational phenomena can be described in atomic units. The result allows a natural interpretation of the possible variation of the gravitational constant without compromising the validity of general relativity. A geometrical interpretation of the scale-covariant theory is possible if the covariant tensors in Riemannian space are replaced by cocovariant cotensors in an integrable Weyl space. A scale-invariant action principle is constructed from the metrical potentials of the integrable Weyl space. Application of the dynamical equations in atomic units to cosmology yields a family of homogeneous solutions characterized by R approx. t for large cosmological times. Equations of motion in atomic units are solved for spherically symmetric gravitational fields. Expressions for perihelion shift and light deflection are derived. They do not differ from the predictions of general relativity except for secular variations, having the age of the universe as a time scale. Similar variations of periods and radii for planetary orbits are also derived

Prevalence of diabetes and its relation with age and sex in Turaif city, northern Saudi Arabia in 2016-2017.

Science.gov (United States)

Alanazi, Nour Homoud; Alsharif, Mahmoud Mohammed; Rasool, Ghazala; Alruwaili, Ahmed Bin Hashash; Alrowaili, Asem Matrouk Zayed; Aldaghmi, Ahmed Saud; Al Shkra, Mohammad Khalil Dughaieum; Alrasheedi, Fatimah Awadh; Alenezi, Ghadah Saleem; Alanazi, Mona Theyab

2017-09-01

The prevalence of diabetes in Saudi Arabia has increased dramatically during the last decades. This increase has been attributed to significant changes in cultural and socio-economic factors. The aim of this study was to determine prevalence of diabetes and its relation with age and sex in Turaif city, northern Saudi Arabia. This was a cross-sectional study carried out during the academic year 2016-2017 over a period of 6 months (October 01, 2016 to March 30, 2017). A total of 1,287 Saudi national individuals of both sexes, aged from 1 year to more than 65 years were included in the study. Data were collected by a predesigned questionnaire covering medical history of diabetes, age and sex. Mean age (± SD) was 24.29 (±13.96) years with the minimum age at 1 year and the maximum age at 93 years, male to female ratio was 42.5% to 57.5%. The total prevalence of DM among the studied population was 5.8% and pre-diabetic cases were 6.8%. There were significant relationships between age/sex, and the occurrence of diabetes among the studied population (pSaudi Arabia was 5.8% and pre-diabetic cases were 6.8%. Awareness campaigns and prevention programs about diabetes should be instituted and the existing ones must be strengthened. Adequate commitment from the Ministry of Health is also advocated.

Activities on covariance estimation in Japanese Nuclear Data Committee

Energy Technology Data Exchange (ETDEWEB)

Shibata, Keiichi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

1997-03-01

Described are activities on covariance estimation in the Japanese Nuclear Data Committee. Covariances are obtained from measurements by using the least-squares methods. A simultaneous evaluation was performed to deduce covariances of fission cross sections of U and Pu isotopes. A code system, KALMAN, is used to estimate covariances of nuclear model calculations from uncertainties in model parameters. (author)

Exploring the inter-relationship of smoking age-at-onset, cigarette consumption and smoking persistence: genes or environment?

Science.gov (United States)

Morley, Katherine I; Lynskey, Michael T; Madden, Pamela A F; Treloar, Susan A; Heath, Andrew C; Martin, Nicholas G

2007-09-01

We investigated the genetic and environmental contributions to covariation between smoking age-at-onset, cigarette consumption and smoking persistence. Multivariate biometrical modelling methods were applied to questionnaire data from Australian twins and their siblings (14 472 individuals from 6247 families). The contributions of genetic and environmental factors to covariation between the three traits were estimated, allowing for sex differences in both trait prevalence and the magnitude of genetic and environmental effects. All traits were moderately heritable in males and females (estimates between 0.40 and 0.62), but there were sex differences in the extent to which additive genetic influences were shared across traits. Twin-specific environmental factors accounted for a substantial proportion of the variance in smoking age-at-onset in females (0.19) and males (0.12), but had little influence (smoking age-at-onset (0.17 for females, 0.19 for males), but a stronger influence on other traits (between 0.39 and 0.49). These results provide some insight into observed sex differences in smoking behaviour, and suggest that searching for pleiotropic genes may prove fruitful. However, further work on phenotypic definitions of smoking behaviour, particularly persistence, is warranted.

Conflicting relationship between age-dependent disorders, valvular heart disease and coronary artery disease by covariance structure analysis: Possible contribution of natriuretic peptide

Science.gov (United States)

Yoshida, Jun; Inoue, Yasunori; Morimoto, Satoshi; Tanaka, Toshikazu; Ogawa, Takayuki

2017-01-01

Background It is conceivable that contemporary valvular heart disease (VHD) is affected largely by an age-dependent atherosclerotic process, which is similar to that observed in coronary artery disease (CAD). However, a comorbid condition of VHD and CAD has not been precisely examined. The first objective of this study was to examine a possible comorbid condition. Provided that there is no comorbidity, the second objective was to search for the possible reasons by using conventional risk factors and plasma B-type natriuretic peptide (BNP) because BNP has a potentiality to suppress atherosclerotic development. Methods The study population consisted of 3,457 patients consecutively admitted to our institution. The possible comorbid condition of VHD and CAD and the factors that influence the comorbidity were examined by covariance structure analysis and multivariate analysis. Results The distribution of the patients with VHD and those with CAD in the histograms showed that the incidence of VHD and the severity of CAD rose with seniority in appearance. The real statistical analysis was planned by covariance structure analysis. The current path model revealed that aging was associated with VHD and CAD severity (P < 0.001 for each); however, as a notable result, there was an inverse association regarding the comorbid condition between VHD and CAD (Correlation coefficient [β]: -0.121, P < 0.001). As the second objective, to clarify the factors leading to this inverse association, the contribution of conventional risk factors, such as age, gender, hypertension, smoking, diabetes, obesity and dyslipidemia, to VHD and CAD were examined by multivariate analysis. However, these factors did not exert an opposing effect on VHD and CAD, and the inverse association defied explanation. Since different pathological mechanisms may contribute to the formation of VHD and CAD, a differentially proposed path model using plasma BNP revealed that an increase in plasma BNP being drawn by

Conflicting relationship between age-dependent disorders, valvular heart disease and coronary artery disease by covariance structure analysis: Possible contribution of natriuretic peptide.

Science.gov (United States)

Fukumoto, Risa; Kawai, Makoto; Minai, Kosuke; Ogawa, Kazuo; Yoshida, Jun; Inoue, Yasunori; Morimoto, Satoshi; Tanaka, Toshikazu; Nagoshi, Tomohisa; Ogawa, Takayuki; Yoshimura, Michihiro

2017-01-01

It is conceivable that contemporary valvular heart disease (VHD) is affected largely by an age-dependent atherosclerotic process, which is similar to that observed in coronary artery disease (CAD). However, a comorbid condition of VHD and CAD has not been precisely examined. The first objective of this study was to examine a possible comorbid condition. Provided that there is no comorbidity, the second objective was to search for the possible reasons by using conventional risk factors and plasma B-type natriuretic peptide (BNP) because BNP has a potentiality to suppress atherosclerotic development. The study population consisted of 3,457 patients consecutively admitted to our institution. The possible comorbid condition of VHD and CAD and the factors that influence the comorbidity were examined by covariance structure analysis and multivariate analysis. The distribution of the patients with VHD and those with CAD in the histograms showed that the incidence of VHD and the severity of CAD rose with seniority in appearance. The real statistical analysis was planned by covariance structure analysis. The current path model revealed that aging was associated with VHD and CAD severity (P < 0.001 for each); however, as a notable result, there was an inverse association regarding the comorbid condition between VHD and CAD (Correlation coefficient [β]: -0.121, P < 0.001). As the second objective, to clarify the factors leading to this inverse association, the contribution of conventional risk factors, such as age, gender, hypertension, smoking, diabetes, obesity and dyslipidemia, to VHD and CAD were examined by multivariate analysis. However, these factors did not exert an opposing effect on VHD and CAD, and the inverse association defied explanation. Since different pathological mechanisms may contribute to the formation of VHD and CAD, a differentially proposed path model using plasma BNP revealed that an increase in plasma BNP being drawn by VHD suppressed the

Neutron spectrum adjustment. The role of covariances

International Nuclear Information System (INIS)

Remec, I.

1992-01-01

Neutron spectrum adjustment method is shortly reviewed. Practical example dealing with power reactor pressure vessel exposure rates determination is analysed. Adjusted exposure rates are found only slightly affected by the covariances of measured reaction rates and activation cross sections, while the multigroup spectra covariances were found important. Approximate spectra covariance matrices, as suggested in Astm E944-89, were found useful but care is advised if they are applied in adjustments of spectra at locations without dosimetry. (author) [sl

Disruption of structural covariance networks for language in autism is modulated by verbal ability.

Science.gov (United States)

Sharda, Megha; Khundrakpam, Budhachandra S; Evans, Alan C; Singh, Nandini C

2016-03-01

The presence of widespread speech and language deficits is a core feature of autism spectrum disorders (ASD). These impairments have often been attributed to altered connections between brain regions. Recent developments in anatomical correlation-based approaches to map structural covariance offer an effective way of studying such connections in vivo. In this study, we employed such a structural covariance network (SCN)-based approach to investigate the integrity of anatomical networks in fronto-temporal brain regions of twenty children with ASD compared to an age and gender-matched control group of twenty-two children. Our findings reflected large-scale disruption of inter and intrahemispheric covariance in left frontal SCNs in the ASD group compared to controls, but no differences in right fronto-temporal SCNs. Interhemispheric covariance in left-seeded networks was further found to be modulated by verbal ability of the participants irrespective of autism diagnosis, suggesting that language function might be related to the strength of interhemispheric structural covariance between frontal regions. Additionally, regional cortical thickening was observed in right frontal and left posterior regions, which was predicted by decreasing symptom severity and increasing verbal ability in ASD. These findings unify reports of regional differences in cortical morphology in ASD. They also suggest that reduced left hemisphere asymmetry and increased frontal growth may not only reflect neurodevelopmental aberrations but also compensatory mechanisms.

Human Papillomavirus Infection Among 2460 Men in Denmark: Prevalence in Relation to Age Using 2 Human Papillomavirus DNA Testing Methods.

Science.gov (United States)

Hebnes, Julie Buchholt; Munk, Christian; Nøhr, Bugge; Nielsen, Ann; Jørgensen, Hans Ole; Iftner, Thomas; Kjaer, Susanne Krüger

2015-08-01

It is crucial to understand the epidemiology and natural history of human papillomavirus (HPV) infection in both men and women, to prevent the increasing HPV-related disease burden in men. Data on HPV prevalence among men in the general population are limited. In this cross-sectional population-based study, we aimed to estimate genital HPV infection prevalence in Danish men using 2 different test methods. Penile swab samples from 2460 male employees and conscripts at military barracks in Denmark were tested for HPV DNA with the hybrid capture 2 (HC2) method, and a polymerase chain reaction (PCR) assay, Inno-LiPA. The overall and age- and type-specific prevalence of HPV infection with 95% confidence intervals (CIs) were estimated, and the correlation between the 2 assays was assessed. The overall HPV prevalence was 22.2% (95% CI, 20.6-23.9) in the HC2 test and 41.8% (95% CI, 39.9-43.8) with PCR. Of the PCR-positive samples, 50.9% were negative in the HC2 test. Of 183 PCR-positive samples that could not be genotyped (HPVX), 88.0% (95% CI, 83.2-92.7) were HC2 negative. The most prevalent types were HPV-51, HPV-16, HPV-66, HPV-53, and HPV-6. The prevalence of high-risk and low-risk HPV peaked among men aged 20 to 29 years, whereas the HPVX prevalence increased with age. Human papillomavirus is highly prevalent in the general male population of Denmark, with HPV-16 and HPV-51 being the most prevalent. Polymerase chain reaction detects twice as many positive samples as HC2 but includes HPVX, possibly representing cutaneous HPV types found on normal genital skin.

Cross-covariance functions for multivariate geostatistics

KAUST Repository

Genton, Marc G.

2015-05-01

Continuously indexed datasets with multiple variables have become ubiquitous in the geophysical, ecological, environmental and climate sciences, and pose substantial analysis challenges to scientists and statisticians. For many years, scientists developed models that aimed at capturing the spatial behavior for an individual process; only within the last few decades has it become commonplace to model multiple processes jointly. The key difficulty is in specifying the cross-covariance function, that is, the function responsible for the relationship between distinct variables. Indeed, these cross-covariance functions must be chosen to be consistent with marginal covariance functions in such a way that the second-order structure always yields a nonnegative definite covariance matrix. We review the main approaches to building cross-covariance models, including the linear model of coregionalization, convolution methods, the multivariate Matérn and nonstationary and space-time extensions of these among others. We additionally cover specialized constructions, including those designed for asymmetry, compact support and spherical domains, with a review of physics-constrained models. We illustrate select models on a bivariate regional climate model output example for temperature and pressure, along with a bivariate minimum and maximum temperature observational dataset; we compare models by likelihood value as well as via cross-validation co-kriging studies. The article closes with a discussion of unsolved problems. © Institute of Mathematical Statistics, 2015.

Cross-covariance functions for multivariate geostatistics

KAUST Repository

Genton, Marc G.; Kleiber, William

2015-01-01

Continuously indexed datasets with multiple variables have become ubiquitous in the geophysical, ecological, environmental and climate sciences, and pose substantial analysis challenges to scientists and statisticians. For many years, scientists developed models that aimed at capturing the spatial behavior for an individual process; only within the last few decades has it become commonplace to model multiple processes jointly. The key difficulty is in specifying the cross-covariance function, that is, the function responsible for the relationship between distinct variables. Indeed, these cross-covariance functions must be chosen to be consistent with marginal covariance functions in such a way that the second-order structure always yields a nonnegative definite covariance matrix. We review the main approaches to building cross-covariance models, including the linear model of coregionalization, convolution methods, the multivariate Matérn and nonstationary and space-time extensions of these among others. We additionally cover specialized constructions, including those designed for asymmetry, compact support and spherical domains, with a review of physics-constrained models. We illustrate select models on a bivariate regional climate model output example for temperature and pressure, along with a bivariate minimum and maximum temperature observational dataset; we compare models by likelihood value as well as via cross-validation co-kriging studies. The article closes with a discussion of unsolved problems. © Institute of Mathematical Statistics, 2015.

Prevalence of type-specific HPV infection by age and grade of cervical cytology: data from the ARTISTIC trial

Science.gov (United States)

Sargent, A; Bailey, A; Almonte, M; Turner, A; Thomson, C; Peto, J; Desai, M; Mather, J; Moss, S; Roberts, C; Kitchener, H C

2008-01-01

Human papillomavirus (HPV) infection causes cervical cancer and premalignant dysplasia. Type-specific HPV prevalence data provide a basis for assessing the impact of HPV vaccination programmes on cervical cytology. We report high-risk HPV (HR-HPV) type-specific prevalence data in relation to cervical cytology for 24 510 women (age range: 20–64; mean age 40.2 years) recruited into the ARTISTIC trial, which is being conducted within the routine NHS Cervical Screening Programme in Greater Manchester. The most common HR-HPV types were HPV16, 18, 31, 51 and 52, which accounted for 60% of all HR-HPV types detected. There was a marked decline in the prevalence of HR-HPV infection with age, but the proportion due to each HPV type did not vary greatly with age. Multiple infections were common below the age of 30 years but less so between age 30 and 64 years. Catch-up vaccination of this sexually active cohort would be expected to reduce the number of women with moderate or worse cytology by 45%, but the number with borderline or mild cytology would fall by only 7%, giving an overall reduction of 12% in the number of women with abnormal cytology and 27% in the number with any HR-HPV infection. In the absence of broader cross-protection, the large majority of low-grade and many high-grade abnormalities may still occur in sexually active vaccinated women. PMID:18392052

The method of covariant symbols in curved space-time

International Nuclear Information System (INIS)

Salcedo, L.L.

2007-01-01

Diagonal matrix elements of pseudodifferential operators are needed in order to compute effective Lagrangians and currents. For this purpose the method of symbols is often used, which however lacks manifest covariance. In this work the method of covariant symbols, introduced by Pletnev and Banin, is extended to curved space-time with arbitrary gauge and coordinate connections. For the Riemannian connection we compute the covariant symbols corresponding to external fields, the covariant derivative and the Laplacian, to fourth order in a covariant derivative expansion. This allows one to obtain the covariant symbol of general operators to the same order. The procedure is illustrated by computing the diagonal matrix element of a nontrivial operator to second order. Applications of the method are discussed. (orig.)

Evaluation of dental care and the prevalence of tooth decay among middle-aged and elderly population of Kaunas city.

Science.gov (United States)

Zubiene, Jurate; Milciuviene, Simona; Klumbiene, Jurate

2009-01-01

The aim of the study was to evaluate the prevalence and the intensity of tooth decay among the middle-aged and elderly population of Kaunas, city, and to assess the need for prostheses as well as the possibilities for oral care. During 2006-2008, we studied 1,141 inhabitants of Kaunas city; the subjects' age was 45-72 years. Oral evaluation technique proposed by the WHO was used in the investigation. We evaluated the prevalence of tooth decay, and its intensity was evaluated using the DMF-T index. We also evaluated dental prostheses, the need for prosthetics, and asked the subjects how they took care of their oral health. The prevalence of tooth decay among middle-aged and elderly population of Kaunas city was 99.9%. The DMF-T index was 21.01+/-0.3 in the age group of 45-54 years, 23.52+/-0.4 - in the age group of 55-64 years, and 25.63+/-0.3 - in the elderly subjects. Full removable dentures were found in 14.0% of the elderly subjects, while 1.0% of the middle-aged subjects and 1.2% of the elderly subjects required full dentures. 57.7% of the subjects aged 45-54 years, 53.1% of the subjects aged 55-64 years, and 43.4% of the elderly subjects brushed their teeth twice daily. The intensity of tooth decay in middle-aged and elderly population of Kaunas city significantly increased with age (21.01-25.63). A relationship was found between oral hygiene status and the DMF-T index. In the middle-aged and elderly population of Kaunas city, the intensity of tooth decay was significantly lower (DMF-T 23.04%) among those who brushed their teeth twice daily than among those who brushed their teeth once daily or less frequently (DMF-T 24.01%). Reduction of the prevalence of tooth decay among middle-aged and elderly population of Kaunas city necessitates alterations in people's attitudes towards dental care, implementation of suitable hygiene habits, and creation and implementation of the dental disease prevention program for adults and the elderly, based on the strategy

Structural covariance networks across healthy young adults and their consistency.

Science.gov (United States)

Guo, Xiaojuan; Wang, Yan; Guo, Taomei; Chen, Kewei; Zhang, Jiacai; Li, Ke; Jin, Zhen; Yao, Li

2015-08-01

To investigate structural covariance networks (SCNs) as measured by regional gray matter volumes with structural magnetic resonance imaging (MRI) from healthy young adults, and to examine their consistency and stability. Two independent cohorts were included in this study: Group 1 (82 healthy subjects aged 18-28 years) and Group 2 (109 healthy subjects aged 20-28 years). Structural MRI data were acquired at 3.0T and 1.5T using a magnetization prepared rapid-acquisition gradient echo sequence for these two groups, respectively. We applied independent component analysis (ICA) to construct SCNs and further applied the spatial overlap ratio and correlation coefficient to evaluate the spatial consistency of the SCNs between these two datasets. Seven and six independent components were identified for Group 1 and Group 2, respectively. Moreover, six SCNs including the posterior default mode network, the visual and auditory networks consistently existed across the two datasets. The overlap ratios and correlation coefficients of the visual network reached the maximums of 72% and 0.71. This study demonstrates the existence of consistent SCNs corresponding to general functional networks. These structural covariance findings may provide insight into the underlying organizational principles of brain anatomy. © 2014 Wiley Periodicals, Inc.

Conformally covariant massless spin-two field equations

International Nuclear Information System (INIS)

Drew, M.S.; Gegenberg, J.D.

1980-01-01

An explicit proof is constructed to show that the field equations for a symmetric tensor field hsub(ab) describing massless spin-2 particles in Minkowski space-time are not covariant under the 15-parameter group SOsub(4,2); this group is usually associated with conformal transformations on flat space, and here it will be considered as a global gauge group which acts upon matter fields defined on space-time. Notwithstanding the above noncovariance, the equations governing the rank-4 tensor Ssub(abcd) constructed from hsub(ab) are shown to be covariant provided the contraction Ssub(ab) vanishes. Conformal covariance is proved by demonstrating the covariance of the equations for the equivalent 5-component complex field; in fact, covariance is proved for a general field equation applicable to massless particles of any spin >0. It is shown that the noncovariance of the hsub(ab) equations may be ascribed to the fact that the transformation behaviour of hsub(ab) is not the same as that of a field consisting of a gauge only. Since this is in contradistinction to the situation for the electromagnetic-field equations, the vector form of the electromagnetic equations is cast into a form which can be duplicated for the hsub(ab)-field. This procedure results in an alternative, covariant, field equation for hsub(ab). (author)

Nursing ward managers' perceptions of pain prevalence at the aged-care facilities in Japan: a nationwide survey.

Science.gov (United States)

Takai, Yukari; Yamamoto-Mitani, Noriko; Fukahori, Hiroki; Kobayashi, Sayuri; Chiba, Yumi

2013-09-01

This study aimed to examine nursing ward managers' perceptions of pain prevalence among older residents and the strategies of pain management at the Health Service Facilities for the Elderly Requiring Care (HSFERC) in Japan and to investigate the factors related to the prevalence. Nursing ward managers in 3,644 HSFERC were asked to participate in this study. Questionnaires were sent to them regarding pain prevalence among the older residents in their wards, their provisions for pain care, and other pain management strategies. The perceived pain prevalence factors were examined statistically. The final sample comprised 439 participants (12.0%). A total of 5,219 residents (22.3%) were recognized as suffering from pain on the investigation day. Only 8 wards (1.8%) used pain management guidelines or care manuals, and 14 (3.2%) used a standardized pain scale. The ward managers' age (p = .008) and nursing experience (p = .006) showed a significant negative association with pain prevalence estimation. Moreover, there was a significant association between the groups' pain prevalence estimation and the nursing managers' beliefs that older adults were less sensitive to pain (p = .01), that pain was common among older people (p = .007), and that the time to treat residents' pain was insufficient (p = .001). The ward managers' perceptions regarding pain prevalence varied; the perceived pain rates were possibly lower than the actual percentages. Insufficient pain management strategies at the HSFERC were also suggested. An appropriate pain management strategy for Japanese aged care and its dissemination are urgently required. Copyright © 2013 American Society for Pain Management Nursing. Published by Elsevier Inc. All rights reserved.

Stroke Prevalence, Mortality and Disability-Adjusted Life Years in Children and Youth Aged 0-19 Years

DEFF Research Database (Denmark)

Krishnamurthi, Rita V; deVeber, Gabrielle; Feigin, Valery L

2015-01-01

, childhood stroke burden in terms of absolute numbers of prevalent strokes, deaths and DALYs remained much higher in developing countries. There is an urgent need to address these disparities with both global and country-level initiatives targeting prevention as well as improved access to acute and chronic...... increases in the global prevalence rates of childhood IS, as well as significant decreases in the global death rate and DALYs rate of all strokes in those of age 0-19 years. While prevalence rates for childhood IS and HS decreased significantly in developed countries, a decline was seen only in HS......, with no change in prevalence rates of IS, in developing countries. The childhood stroke DALY rates in 2013 were 13.3 (95% UI 10.6-17.1) for IS and 92.7 (95% UI 80.5-109.7) for HS per 100,000. While the prevalence of childhood IS compared to childhood HS was similar globally, the death rate and DALY rate of HS...

Exploring the variability in Behçet's disease prevalence: a meta-analytical approach.

Science.gov (United States)

Maldini, Carla; Druce, Katie; Basu, Neil; LaValley, Michael P; Mahr, Alfred

2018-01-01

Surveys of Behçet's disease (BD) have shown substantial geographic variations in prevalence, but some of these differences may result from methodological inconsistencies. This meta-analysis explored the effect of geographic location and study methodology on the prevalence of BD. We systematically searched the literature in electronic databases and by handsearching to identify population-based prevalence surveys of BD. Studies were eligible if they provided an original population-based prevalence estimate for BD with the number of prevalent cases identified in the study area. Pooled prevalence proportions across all studies were computed by using random effects models based on a Poisson normal distribution. Pre-defined subgroup analyses and meta-regression were used to investigate the effect of covariates on the prevalence proportions. We included 45 reports published from 1974 to 2015 and covering worldwide areas. The pooled estimates of prevalence proportions (expressed as cases/100 000 inhabitants) were 10.3 (95% CI 6.1, 17.7) for all studies and 119.8 (59.8, 239.9) for Turkey, 31.8 (12.9, 78.4) for the Middle East, 4.5 (2.2, 9.4) for Asia and 3.3 (2.1, 5.2) for Europe. Subgroup analyses showed a strikingly greater prevalence for studies with a sample survey design than a census design [82.5 (95% CI 47.3, 143.9) vs 3.6 (2.6, 5.1)]. Metaregression identified study design as an independent covariate significantly affecting BD prevalence proportions. Differences in BD prevalence proportions likely reflect a combination of true geographic variation and methodological artefacts. In particular, use of a sample or census study design may strongly affect the estimated prevalence. © The Author 2017. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Evaluation of covariance for 238U cross sections

International Nuclear Information System (INIS)

Kawano, Toshihiko; Nakamura, Masahiro; Matsuda, Nobuyuki; Kanda, Yukinori

1995-01-01

Covariances of 238 U are generated using analytic functions for representation of the cross sections. The covariances of the (n,2n) and (n,3n) reactions are derived with a spline function, while the covariances of the total and the inelastic scattering cross section are estimated with a linearized nuclear model calculation. (author)

GLq(N)-covariant quantum algebras and covariant differential calculus

International Nuclear Information System (INIS)

Isaev, A.P.; Pyatov, P.N.

1993-01-01

We consider GL q (N)-covariant quantum algebras with generators satisfying quadratic polynomial relations. We show that, up to some inessential arbitrariness, there are only two kinds of such quantum algebras, namely, the algebras with q-deformed commutation and q-deformed anticommutation relations. The connection with the bicovariant differential calculus on the linear quantum groups is discussed. (orig.)

Asset allocation with different covariance/correlation estimators

OpenAIRE

Μανταφούνη, Σοφία

2007-01-01

The subject of the study is to test whether the use of different covariance – correlation estimators than the historical covariance matrix that is widely used, would help in portfolio optimization through the mean-variance analysis. In other words, if an investor would like to use the mean-variance analysis in order to invest in assets like stocks or indices, would it be of some help to use more sophisticated estimators for the covariance matrix of the returns of his portfolio? The procedure ...

Examination of the causes of covariation between conduct disorder symptoms and vulnerability to drug dependence.

Science.gov (United States)

Button, Tanya M M; Hewitt, John K; Rhee, Soo Hyun; Young, Susan E; Corley, Robin P; Stallings, Michael C

2006-02-01

Conduct disorder (CD) symptoms and substance dependence commonly co-occur. Both phenotypes are highly heritable and a common genetic influence on the covariation has been suggested. The aim of this study was to determine the extent to which genes and environment contribute to the covariance between CD and drug dependence using twins from the Colorado Longitudinal Twin Sample and the Colorado Twin Registry. A total of 880 twin pairs (237 monozygotic [MZ] female, 195 MZ male, 116 dizygotic [DZ] female, 118 DZ male and 214 DZ opposite-sex) aged 13 to 18 (mean = 15.65) were included in the analysis. CD was assessed by lifetime Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV; American Psychiatric Association, 1994) symptom count and a polysubstance dependence vulnerability index was developed from responses to the Composite International Diagnostic Interview--Substance Abuse Module. A bivariate Cholesky Decomposition model was used to partition the cause of variation and covariation of the two phenotypes. No sex-limitation was observed in our data, and male and female parameter estimates were constrained to be equal. Both CD symptoms and dependence vulnerability were significantly heritable, and genes, shared environment and nonshared environment all contributed to the covariation between them. Genes contributed 35% of the phenotypic covariance, shared environment contributed 46%, and nonshared environmental influences contributed the remaining 19% to the phenotypic covariance. Therefore, there appears to be pleiotropic genetic influence on CD symptoms and dependence vulnerability.

Students’ Covariational Reasoning in Solving Integrals’ Problems

Science.gov (United States)

Harini, N. V.; Fuad, Y.; Ekawati, R.

2018-01-01

Covariational reasoning plays an important role to indicate quantities vary in learning calculus. This study investigates students’ covariational reasoning during their studies concerning two covarying quantities in integral problem. Six undergraduate students were chosen to solve problems that involved interpreting and representing how quantities change in tandem. Interviews were conducted to reveal the students’ reasoning while solving covariational problems. The result emphasizes that undergraduate students were able to construct the relation of dependent variables that changes in tandem with the independent variable. However, students faced difficulty in forming images of continuously changing rates and could not accurately apply the concept of integrals. These findings suggest that learning calculus should be increased emphasis on coordinating images of two quantities changing in tandem about instantaneously rate of change and to promote conceptual knowledge in integral techniques.

Forecasting Covariance Matrices: A Mixed Frequency Approach

DEFF Research Database (Denmark)

Halbleib, Roxana; Voev, Valeri

This paper proposes a new method for forecasting covariance matrices of financial returns. The model mixes volatility forecasts from a dynamic model of daily realized volatilities estimated with high-frequency data with correlation forecasts based on daily data. This new approach allows for flexi......This paper proposes a new method for forecasting covariance matrices of financial returns. The model mixes volatility forecasts from a dynamic model of daily realized volatilities estimated with high-frequency data with correlation forecasts based on daily data. This new approach allows...... for flexible dependence patterns for volatilities and correlations, and can be applied to covariance matrices of large dimensions. The separate modeling of volatility and correlation forecasts considerably reduces the estimation and measurement error implied by the joint estimation and modeling of covariance...

Covariance upperbound controllers for networked control systems

International Nuclear Information System (INIS)

Ko, Sang Ho

2012-01-01

This paper deals with designing covariance upperbound controllers for a linear system that can be used in a networked control environment in which control laws are calculated in a remote controller and transmitted through a shared communication link to the plant. In order to compensate for possible packet losses during the transmission, two different techniques are often employed: the zero-input and the hold-input strategy. These use zero input and the latest control input, respectively, when a packet is lost. For each strategy, we synthesize a class of output covariance upperbound controllers for a given covariance upperbound and a packet loss probability. Existence conditions of the covariance upperbound controller are also provided for each strategy. Through numerical examples, performance of the two strategies is compared in terms of feasibility of implementing the controllers

ERRORJ. Covariance processing code system for JENDL. Version 2

International Nuclear Information System (INIS)

Chiba, Gou

2003-09-01

ERRORJ is the covariance processing code system for Japanese Evaluated Nuclear Data Library (JENDL) that can produce group-averaged covariance data to apply it to the uncertainty analysis of nuclear characteristics. ERRORJ can treat the covariance data for cross sections including resonance parameters as well as angular distributions and energy distributions of secondary neutrons which could not be dealt with by former covariance processing codes. In addition, ERRORJ can treat various forms of multi-group cross section and produce multi-group covariance file with various formats. This document describes an outline of ERRORJ and how to use it. (author)

The impact of case definition on attention-deficit/hyperactivity disorder prevalence estimates in community-based samples of school-aged children.

Science.gov (United States)

McKeown, Robert E; Holbrook, Joseph R; Danielson, Melissa L; Cuffe, Steven P; Wolraich, Mark L; Visser, Susanna N

2015-01-01

To determine the impact of varying attention-deficit/hyperactivity disorder (ADHD) diagnostic criteria, including new DSM-5 criteria, on prevalence estimates. Parent and teacher reports identified high- and low-screen children with ADHD from elementary schools in 2 states that produced a diverse overall sample. The parent interview stage included the Diagnostic Interview Schedule for Children-IV (DISC-IV), and up to 4 additional follow-up interviews. Weighted prevalence estimates, accounting for complex sampling, quantified the impact of varying ADHD criteria using baseline and the final follow-up interview data. At baseline 1,060 caregivers were interviewed; 656 had at least 1 follow-up interview. Teachers and parents reported 6 or more ADHD symptoms for 20.5% (95% CI = 18.1%-23.2%) and 29.8% (CI = 24.5%-35.6%) of children respectively, with criteria for impairment and onset by age 7 years (DSM-IV) reducing these proportions to 16.3% (CI = 14.7%-18.0%) and 17.5% (CI = 13.3%-22.8%); requiring at least 4 teacher-reported symptoms reduced the parent-reported prevalence to 8.9% (CI = 7.4%-10.6%). Revising age of onset to 12 years per DSM-5 increased the 8.9% estimate to 11.3% (CI = 9.5%-13.3%), with a similar increase seen at follow-up: 8.2% with age 7 onset (CI = 5.9%-11.2%) versus 13.0% (CI = 7.6%-21.4%) with onset by age 12. Reducing the number of symptoms required for those aged 17 and older increased the overall estimate to 13.1% (CI = 7.7%-21.5%). These findings quantify the impact on prevalence estimates of varying case definition criteria for ADHD. Further research of impairment ratings and data from multiple informants is required to better inform clinicians conducting diagnostic assessments. DSM-5 changes in age of onset and number of symptoms required for older adolescents appear to increase prevalence estimates, although the full impact is uncertain due to the age of our sample. Published by Elsevier Inc.

ACORNS, Covariance and Correlation Matrix Diagonalization

International Nuclear Information System (INIS)

Szondi, E.J.

1990-01-01

1 - Description of program or function: The program allows the user to verify the different types of covariance/correlation matrices used in the activation neutron spectrometry. 2 - Method of solution: The program performs the diagonalization of the input covariance/relative covariance/correlation matrices. The Eigen values are then analyzed to determine the rank of the matrices. If the Eigen vectors of the pertinent correlation matrix have also been calculated, the program can perform a complete factor analysis (generation of the factor matrix and its rotation in Kaiser's 'varimax' sense to select the origin of the correlations). 3 - Restrictions on the complexity of the problem: Matrix size is limited to 60 on PDP and to 100 on IBM PC/AT

[The prevalence of radiological osteoarthritis in relation to age, gender, birth-year cohort, and ethnic origins].

Science.gov (United States)

Spahn, G; Schiele, R; Hofmann, G O; Schiltenwolf, M; Grifka, J; Vaitl, T; Schneider, S; Liebers, F; Klinger, H M

2011-04-01

This metaanalysis was performed to evaluate the prevalence of the radiological assessed knee osteoarthritis in the whole community. Medical databases (Medline, EMBASE, Cochrane) were searched for the strategy: ["Osteoarthritis" and "Knee" and "Prevalence"]. The deadline for the search was 31.12.2009. Two investigators (first and senior author) independently made the selection from 17 studies (from a total of 1428) according to the inclusion criteria: a cross-sectional study of the whole community, radiological investigation and definition of knee ROA by an established radiological score. Only studies in English or German language were evaluated. Effect sizes (event rate, odds ratio [OR] and confidence interval [CI]) were calculated by the software "Comprehensive Metaanalysis V2". Study heterogeneity (I2) was determined accordingly to Higgins. The kappa index for interobserver validity was k = 0.948. All studies judged the grade of osteoarthritis according to the Kellgren-Lawrence (KL) score. For calculation of knee ROA KL grades 2+ were estimated only. The total prevalence of knee ROA was 24.3 % (CI 23.4-25.2 %). The whole prevalence in male patients was 24.3 % (CI 23.4-25.2 %); I2 = 59.4 (p = 0.002) and in female patients 32.6 % (CI 31.8-33.4 %); I2 = 49,1 (p < 0.001). Younger male patients (age 50-) had a prevalence of 5.6 (CI 4.5-6.8). In older patients (80+) the male prevalence was 44.5 % (CI 39.6-49.5 %). In this age group female patients had a prevalence of 71.6 % (CI 67.6-75.3 %). The higher prevalence of knee ROA in female patients was significant (OR = 1.8 [1.7-1.9]; I2 = 46.0 [p < 0.001]). The prevalence of knee ROA was higher in male Asians compared with male Caucasians (OR = 1.1, CI 0.9-1.2; p = 0.080) in tendency. This difference was significant in female patients (OR = 2.2; CI 2.0-2.4; p < 0.001). Furthermore another trend was evaluated. Female patients (70-79 years) from the birth-year cohort 1920- had a prevalence of 37.8 % (CI 35.9-39.7)%. In

Condition Number Regularized Covariance Estimation*

Science.gov (United States)

Won, Joong-Ho; Lim, Johan; Kim, Seung-Jean; Rajaratnam, Bala

2012-01-01

Estimation of high-dimensional covariance matrices is known to be a difficult problem, has many applications, and is of current interest to the larger statistics community. In many applications including so-called the “large p small n” setting, the estimate of the covariance matrix is required to be not only invertible, but also well-conditioned. Although many regularization schemes attempt to do this, none of them address the ill-conditioning problem directly. In this paper, we propose a maximum likelihood approach, with the direct goal of obtaining a well-conditioned estimator. No sparsity assumption on either the covariance matrix or its inverse are are imposed, thus making our procedure more widely applicable. We demonstrate that the proposed regularization scheme is computationally efficient, yields a type of Steinian shrinkage estimator, and has a natural Bayesian interpretation. We investigate the theoretical properties of the regularized covariance estimator comprehensively, including its regularization path, and proceed to develop an approach that adaptively determines the level of regularization that is required. Finally, we demonstrate the performance of the regularized estimator in decision-theoretic comparisons and in the financial portfolio optimization setting. The proposed approach has desirable properties, and can serve as a competitive procedure, especially when the sample size is small and when a well-conditioned estimator is required. PMID:23730197

Heteroscedasticity resistant robust covariance matrix estimator

Czech Academy of Sciences Publication Activity Database

Víšek, Jan Ámos

2010-01-01

Roč. 17, č. 27 (2010), s. 33-49 ISSN 1212-074X Grant - others:GA UK(CZ) GA402/09/0557 Institutional research plan: CEZ:AV0Z10750506 Keywords : Regression * Covariance matrix * Heteroscedasticity * Resistant Subject RIV: BB - Applied Statistics, Operational Research http://library.utia.cas.cz/separaty/2011/SI/visek-heteroscedasticity resistant robust covariance matrix estimator.pdf

How much do genetic covariances alter the rate of adaptation?

Science.gov (United States)

Agrawal, Aneil F; Stinchcombe, John R

2009-03-22

Genetically correlated traits do not evolve independently, and the covariances between traits affect the rate at which a population adapts to a specified selection regime. To measure the impact of genetic covariances on the rate of adaptation, we compare the rate fitness increases given the observed G matrix to the expected rate if all the covariances in the G matrix are set to zero. Using data from the literature, we estimate the effect of genetic covariances in real populations. We find no net tendency for covariances to constrain the rate of adaptation, though the quality and heterogeneity of the data limit the certainty of this result. There are some examples in which covariances strongly constrain the rate of adaptation but these are balanced by counter examples in which covariances facilitate the rate of adaptation; in many cases, covariances have little or no effect. We also discuss how our metric can be used to identify traits or suites of traits whose genetic covariances to other traits have a particularly large impact on the rate of adaptation.

Prevalence of nocturnal enuresis and related risk factors in school-age children in Egypt: an epidemiological study.

Science.gov (United States)

Hamed, Ahmed; Yousf, Fouad; Hussein, Mohamed M

2017-03-01

To determine the prevalence of mono-symptomatic nocturnal enuresis (MNE) and its risk factors among school-age children in our community. A cross-sectional study included school-age children from two governorates in south of Egypt. A questionnaire was presented to randomly selected students. It consisted of 3 domains: Domain 1 included questions about MNE, domain 2 was about risk factors for MNE, and domain 3 was about management of MNE. The study included 4652 students (9 ± 2 years) from 12 primary schools (51 % males and 49 % females). Of 4652 students, 834 (18 %) had NE, with no significant difference between rural and urban areas (17.5 vs. 18.4 %, p = 0.4). Younger age categories showed higher prevalence of MNE than in older children. MNE caused moderate-to-severe bother for 44.5 and 87.8 % of students and parents, respectively. Urinary tract infection, pinworm infestation, constipation, and caffeine over-consumption significantly associated with MNE. Family history of MNE was positive in 84.7 %. Daytime incontinence coexisted in 16 % of cases. Children with ≥4 siblings and birth order ≥3 had more prevalent MNE. Deep sleepers and exposure to problems/violence correlated positively with occurrence of MNE. Father's level of education and work status, mother education, number of children per room, and socioeconomic status significantly associated with occurrence of MNE. There was no significant correlation between gender and prevalence of MNE. No treatment was used in 53.2 % of cases. In the Egyptian community, pinworm infestation, UTI, constipation, and overconsumption of caffeine-containing beverages are potential reversible risk factors for MNE in school-age children.

Comparative Analyses of Phenotypic Trait Covariation within and among Populations.

Science.gov (United States)

Peiman, Kathryn S; Robinson, Beren W

2017-10-01

Many morphological, behavioral, physiological, and life-history traits covary across the biological scales of individuals, populations, and species. However, the processes that cause traits to covary also change over these scales, challenging our ability to use patterns of trait covariance to infer process. Trait relationships are also widely assumed to have generic functional relationships with similar evolutionary potentials, and even though many different trait relationships are now identified, there is little appreciation that these may influence trait covariation and evolution in unique ways. We use a trait-performance-fitness framework to classify and organize trait relationships into three general classes, address which ones more likely generate trait covariation among individuals in a population, and review how selection shapes phenotypic covariation. We generate predictions about how trait covariance changes within and among populations as a result of trait relationships and in response to selection and consider how these can be tested with comparative data. Careful comparisons of covariation patterns can narrow the set of hypothesized processes that cause trait covariation when the form of the trait relationship and how it responds to selection yield clear predictions about patterns of trait covariation. We discuss the opportunities and limitations of comparative approaches to evaluate hypotheses about the evolutionary causes and consequences of trait covariation and highlight the importance of evaluating patterns within populations replicated in the same and in different selective environments. Explicit hypotheses about trait relationships are key to generating effective predictions about phenotype and its evolution using covariance data.

Earth Observation System Flight Dynamics System Covariance Realism

Science.gov (United States)

Zaidi, Waqar H.; Tracewell, David

2016-01-01

This presentation applies a covariance realism technique to the National Aeronautics and Space Administration (NASA) Earth Observation System (EOS) Aqua and Aura spacecraft based on inferential statistics. The technique consists of three parts: collection calculation of definitive state estimates through orbit determination, calculation of covariance realism test statistics at each covariance propagation point, and proper assessment of those test statistics.

Determination of covariant Schwinger terms in anomalous gauge theories

International Nuclear Information System (INIS)

Kelnhofer, G.

1991-01-01

A functional integral method is used to determine equal time commutators between the covariant currents and the covariant Gauss-law operators in theories which are affected by an anomaly. By using a differential geometrical setup we show how the derivation of consistent- and covariant Schwinger terms can be understood on an equal footing. We find a modified consistency condition for the covariant anomaly. As a by-product the Bardeen-Zumino functional, which relates consistent and covariant anomalies, can be interpreted as connection on a certain line bundle over all gauge potentials. Finally the commutator anomalies are calculated for the two- and four dimensional case. (Author) 13 refs

Genetic and Environmental Contributions to Covariation Between DHEA and Testosterone in Adolescent Twins.

Science.gov (United States)

Van Hulle, Carol A; Moore, Mollie N; Shirtcliff, Elizabeth A; Lemery-Chalfant, Kathryn; Goldsmith, H Hill

2015-05-01

Although several studies have shown that pubertal tempo and timing are shaped by genetic and environmental factors, few studies consider to what extent endocrine triggers of puberty are shaped by genetic and environmental factors. Doing so moves the field from examining correlated developmentally-sensitive biomarkers toward understanding what drives those associations. Two puberty related hormones, dehydroepiandrosterone and testosterone, were assayed from salivary samples in 118 MZ (62 % female), 111 same sex DZ (46 % female) and 103 opposite-sex DZ twin pairs, aged 12-16 years (M = 13.1, SD = 1.3). Pubertal status was assessed with a composite of mother- and self-reports. We used biometric models to estimate the genetic and environmental influences on the variance and covariance in testosterone and DHEA, with and without controlling for their association with puberty, and to test for sex differences. In males, the variance in testosterone and pubertal status was due to shared and non-shared environmental factors; variation in DHEA was due to genetic and non-shared environmental factors. In females, variance in testosterone was due to genetic and non-shared environmental factors; genetic, shared, and non-shared environmental factors contributed equally to variation in DHEA. In males, the testosterone-DHEA covariance was primarily due to shared environmental factors that overlapped with puberty as well as shared and non-shared environmental covariation specific to testosterone and DHEA. In females, the testosterone-DHEA covariance was due to genetic factors overlapping with pubertal status, and shared and non-shared environmental covariation specific to testosterone and DHEA.

Coherent states and covariant semi-spectral measures

International Nuclear Information System (INIS)

Scutaru, H.

1976-01-01

The close connection between Mackey's theory of imprimitivity systems and the so called generalized coherent states introduced by Perelomov is established. Coherent states give a covariant description of the ''localization'' of a quantum system in the phase space in a similar way as the imprimitivity systems give a covariant description of the localization of a quantum system in the configuration space. The observation that for any system of coherent states one can define a covariant semi-spectral measure made possible a rigurous formulation of this idea. A generalization of the notion of coherent states is given. Covariant semi-spectral measures associated with systems of coherent states are defined and characterized. Necessary and sufficient conditions for a unitary representation of a Lie group to be i) a subrepresentation of an induced one and ii) a representation with coherent states are given (author)

Unmet demand for training among mature age Australians: Prevalence, differentials and perceived causes.

Science.gov (United States)

Adair, Tim; Lourey, Emma; Taylor, Philip

2016-03-01

To explore the prevalence of unmet demand for training by mature age Australians and to identify the main barriers to accessing training. A total of 3007 Australians aged 45-74 years were surveyed using Computer Assisted Telephone Interviewing. The sample frame was randomly selected and stratified based on the capital city and the rest of the state, and data were weighted to be nationally representative. Over one-third (37%) of respondents who had worked in the past five years reported wanting to attend some form of training but were unable to; these were most likely women and those aged 45-54 year. Commonly cited reasons for not being able to attend training included not being able to fit it in with work commitments, affordability and employer reluctance. Reduction of these barriers to workplace training can improve mature age people's ability to remain engaged in the workforce. © 2015 AJA Inc.

Prevalência e severidade da cárie dentária em escolares de seis e doze anos de idade Prevalence and severity of dental caries among schoolchildren aged six and twelve

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Jefferson Luiz Traebert

2001-06-01

Full Text Available OBJETIVO: Investigar a prevalência e a severidade da cárie dentária e as necessidades de tratamento em escolares de 6 e 12 anos de idade, comparando-se os alunos de escolas públicas com os de privadas. MÉTODOS: Foi estudada a população de escolares do município de Blumenau, SC, a partir de uma amostra de 1.473 escolares, representativa de quatro estratos: escolares de 6 anos de escolas públicas, de 6 anos de escolas privadas, de 12 anos de escolas públicas e de 12 anos de escolas privadas. Utilizaram-se os critérios de diagnóstico da Organização Mundial de Saúde (1997. RESULTADOS: A prevalência de cárie na dentição decídua em escolares de 6 anos foi de 60,9% em escolas públicas e de 34,9% em escolas privadas (pOBJECTIVE: To determine the prevalence and severity of dental caries and to assess treatment needs among schoolchildren aged 6 and 12 in Blumenau, Brazil, and to compare the results found for private and public schools. METHODS: A schoolchildren population of Blumenau, SC, Brazil, was studied. A random sample of 1,473 schoolchildren from Blumenau, Brazil, was obtained. Four strata were studied: 6 and 12 years old schoolchildren attending public and private schools. WHO (1997 criteria for caries diagnosis and treatment needs were used. RESULTS: The prevalence of caries in the primary dentition of 6-years-old children was 60.9% and 34.9% in public and private schools (p<0.0001, respectively. The mean DMF-T for children aged 6 was 2.98 and 1.32 for public and private schools, respectively, (p<0.0001, and 2.42 for the whole sample. The prevalence of caries in the permanent dentition of 12-years-old children was 54.7% and the mean DMF-T was 1.46 for public schools. The response rate for private schools was low and the results could not be analyzed. Forty-two percent and 77.0% of children aged six of public and private schools, respectively, had no treatment needs. For those aged 12, the percentage was 53.0% for public

Dehydroepiandrosterone impacts working memory by shaping cortico-hippocampal structural covariance during development.

Science.gov (United States)

Nguyen, Tuong-Vi; Wu, Mia; Lew, Jimin; Albaugh, Matthew D; Botteron, Kelly N; Hudziak, James J; Fonov, Vladimir S; Collins, D Louis; Campbell, Benjamin C; Booij, Linda; Herba, Catherine; Monnier, Patricia; Ducharme, Simon; McCracken, James T

2017-12-01

Existing studies suggest that dehydroepiandrosterone (DHEA) may be important for human brain development and cognition. For example, molecular studies have hinted at the critical role of DHEA in enhancing brain plasticity. Studies of human brain development also support the notion that DHEA is involved in preserving cortical plasticity. Further, some, though not all, studies show that DHEA administration may lead to improvements in working memory in adults. Yet these findings remain limited by an incomplete understanding of the specific neuroanatomical mechanisms through which DHEA may impact the CNS during development. Here we examined associations between DHEA, cortico-hippocampal structural covariance, and working memory (216 participants [female=123], age range 6-22 years old, mean age: 13.6 +/-3.6 years, each followed for a maximum of 3 visits over the course of 4 years). In addition to administering performance-based, spatial working memory tests to these children, we also collected ecological, parent ratings of working memory in everyday situations. We found that increasingly higher DHEA levels were associated with a shift toward positive insular-hippocampal and occipito-hippocampal structural covariance. In turn, DHEA-related insular-hippocampal covariance was associated with lower spatial working memory but higher overall working memory as measured by the ecological parent ratings. Taken together with previous research, these results support the hypothesis that DHEA may optimize cortical functions related to general attentional and working memory processes, but impair the development of bottom-up, hippocampal-to-cortical connections, resulting in impaired encoding of spatial cues. Copyright © 2017 Elsevier Ltd. All rights reserved.

Large Covariance Estimation by Thresholding Principal Orthogonal Complements.

Science.gov (United States)

Fan, Jianqing; Liao, Yuan; Mincheva, Martina

2013-09-01

This paper deals with the estimation of a high-dimensional covariance with a conditional sparsity structure and fast-diverging eigenvalues. By assuming sparse error covariance matrix in an approximate factor model, we allow for the presence of some cross-sectional correlation even after taking out common but unobservable factors. We introduce the Principal Orthogonal complEment Thresholding (POET) method to explore such an approximate factor structure with sparsity. The POET estimator includes the sample covariance matrix, the factor-based covariance matrix (Fan, Fan, and Lv, 2008), the thresholding estimator (Bickel and Levina, 2008) and the adaptive thresholding estimator (Cai and Liu, 2011) as specific examples. We provide mathematical insights when the factor analysis is approximately the same as the principal component analysis for high-dimensional data. The rates of convergence of the sparse residual covariance matrix and the conditional sparse covariance matrix are studied under various norms. It is shown that the impact of estimating the unknown factors vanishes as the dimensionality increases. The uniform rates of convergence for the unobserved factors and their factor loadings are derived. The asymptotic results are also verified by extensive simulation studies. Finally, a real data application on portfolio allocation is presented.

Prevalence and impact of primary headache disorders among students and working population in 18-25 years age group

Directory of Open Access Journals (Sweden)

Gowri Aishwarya S, Eswari N, Chandrasekar M, Chandra Prabha J

2014-04-01

Full Text Available Background: Headache or cephalalgia is defined as pain in the head. Headache is an extremely common symptom that may have a profound impact on peoples’ functioning and quality of life. According to International Classification of Headache Disorders (ICHD, they are Primary and Secondary headaches. Primary Headaches are triggered by stress, alcohol, changes in sleep pattern, anxiety, poor posture, all of which are part and parcel our day-to-day life. The study was performed to investigate the prevalence of primary headache disorders and its severity of impact among students and working population in the age group 18-25. Methods: The study was conducted on 718 subjects of which 483 subjects were medical and engineering students from the age group 18-21 and 235 subjects were working people from the age group 22-25. Written consent was taken from each of them. Headache Impact Test-6 (version 1.1 and the HARDSHIP Questionnaire by Timothy Steiner et al. were the questionnaires used to diagnose the severity of impact and the type of headache respectively. The study was ethically approved by Ethical Clearance Board of MAHER University. People suffering from psychiatric illness were excluded from the study. Result: There was increased prevalence of migraine in the age group 18-21 and tension type headache in the age group 22-25.Over 50%of subjects from both the age groups had headaches that have substantial to severe impact on their lives. There was no significant gender variation in headache prevalence.

Current Age, Age at First Sex, Age at First Homelessness, and HIV Risk Perceptions Predict Sexual Risk Behaviors among Sexually Active Homeless Adults

Directory of Open Access Journals (Sweden)

Diane Santa Maria

2018-01-01

Full Text Available While HIV disproportionately impacts homeless individuals, little is known about the prevalence of HIV risk behaviors in the southwest and how age factors and HIV risk perceptions influence sexual risk behaviors. We conducted a secondary data analysis (n = 460 on sexually active homeless adults from a cross-sectional study of participants (n = 610 recruited from homeless service locations, such as shelters and drop-in centers, in an understudied region of the southwest. Covariate-adjusted logistic regressions were used to assess the impact of age at homelessness onset, current age, age at first sex, and HIV risk perceptions on having condomless sex, new sexual partner(s, and multiple sexual partners (≥4 sexual partners in the past 12 months. Individuals who first experienced homelessness by age 24 were significantly more likely to report condomless sex and multiple sexual partners in the past year than those who had a later onset of their first episode of homelessness. Individuals who were currently 24 years or younger were more likely to have had condomless sex, new sexual partners, and multiple sexual partners in the past 12 months than those who were 25 years or older. Those who had low perceived HIV risk had lower odds of all three sexual risk behaviors. Social service and healthcare providers should consider a younger age at homelessness onset when targeting HIV prevention services to youth experiencing homelessness.

Age- and gender-specific prevalence and risk factors for depressive symptoms in the elderly: a population-based study.

Science.gov (United States)

Glaesmer, H; Riedel-Heller, S; Braehler, E; Spangenberg, L; Luppa, M

2011-10-01

Information on the prevalence and risk factors for depressive disorders in old age is of considerable interest for the assessment of future needs of the health care system. The aim of the study is to determine age- and gender-specific prevalence of major depression (MD), minor depression (MiD), and depressive symptoms, and to analyze risk factors associated with depressive symptoms. A representative sample of the German population of 1,659 individuals aged 60 to 85 years were visited at home and answered self-rating questionnaires. Depressive symptoms and syndromes (MD, MiD) were assessed using the Patient Health Questionnaire (PHQ-9). Factors associated with depressive symptoms were determined with linear regression models for the total sample and for men and women separately. Depressive symptoms were found in 28.7% of the participants, while 6.6% were affected by MD or MiD. The highest prevalence of MD and depressive symptoms was found in the oldest age groups. MiD showed an unsteady course across age groups in both sexes. In the total sample as well as in the male subsample, depressive symptoms were significantly associated with increasing age, lower household income, an increasing number of medical conditions, and lower social support. In women only, the number of medical conditions and lacking social support were significantly associated with depressive symptoms. Depressive symptoms are common in old age and occur on a spectrum ranging from very mild forms to MD. The potential modifiability of a number of risk factors for depressive symptoms opens possibilities of secondary prevention such as treatment of chronic diseases as well as support in requirements of daily living.

Education, Income, and Employment and Prevalence of Chronic Disease Among American Indian/Alaska Native Elders.

Science.gov (United States)

Adamsen, Collette; Schroeder, Shawnda; LeMire, Steven; Carter, Paula

2018-03-22

Chronic disease studies have omitted analyses of the American Indian/Alaska Native (AI/AN) population, relied on small samples of AI/ANs, or focused on a single disease among AI/ANs. We measured the influence of income, employment status, and education level on the prevalence of chronic disease among 14,632 AI/AN elders from 2011 through 2014. We conducted a national survey of AI/AN elders (≥55 y) to identify health and social needs. Using these data, we computed cross-tabulations for each independent variable (annual personal income, employment status, education level), 2 covariates (age, sex), and presence of any chronic disease. We also compared differences in values and used a binary logistic regression model to control for age and sex. Most AI/AN elders (89.7%) had been diagnosed with at least one chronic disease. AI/AN elders were also more than twice as likely to have diabetes and more likely to have arthritis. AI/AN elders with middle-to-low income levels and who were unemployed were more likely to have a chronic disease than were high-income and employed AI/AN elders. Addressing disparities in chronic disease prevalence requires focus on more than access to and cost of health care. Economic development and job creation for all age cohorts in tribal communities may decrease the prevalence of long-term chronic diseases and may improve the financial status of the tribe. An opportunity exists to address health disparities through social and economic equity among tribal populations.

Trends in adolescent alcohol use: Effects of age, sex and cohort on prevalence and heritability

NARCIS (Netherlands)

Geels, L.M.; Bartels, M.; van Beijsterveldt, C.E.M.; Willemsen, G.; van der Aa, N.; Boomsma, D.I.; Vink, J.M.

2012-01-01

Aims To determine the effect of age, sex and cohort on the prevalence and genetic architecture of adolescent alcohol use (AAU). Design Survey study in participants registered with the Netherlands Twin Register. Setting Twins from the general population. Participants Two cohorts (data collected in

Some remarks on general covariance of quantum theory

International Nuclear Information System (INIS)

Schmutzer, E.

1977-01-01

If one accepts Einstein's general principle of relativity (covariance principle) also for the sphere of microphysics (quantum, mechanics, quantum field theory, theory of elemtary particles), one has to ask how far the fundamental laws of traditional quantum physics fulfil this principle. Attention is here drawn to a series of papers that have appeared during the last years, in which the author criticized the usual scheme of quantum theory (Heisenberg picture, Schroedinger picture etc.) and presented a new foundation of the basic laws of quantum physics, obeying the 'principle of fundamental covariance' (Einstein's covariance principle in space-time and covariance principle in Hilbert space of quantum operators and states). (author)

Age- and Gender-Specific Prevalence of Risk Factors in Patients with First-Ever Ischemic Stroke in China

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Xiao-ying Yao

2012-01-01

Full Text Available Background. Evidences are accumulating that age and gender have great impact on the distribution of stroke risk factors. Such data are lacking in Chinese population. Methods. 1027 patients with first-ever ischemic stroke (IS were recruited and divided into young adult (80 years groups according to stroke onset ages. Vascular risk factors were collected and compared among groups. Results. Female patients were globally older than male patients at stroke onset and having higher prevalence of diabetes mellitus (DM, heart diseases, and atrial fibrillation (AF. However, females were less likely to drink heavily or smoke than males. Young patients had a much higher proportion of smoking and drinking than middle-aged and very old patients and the highest family history of hypertension, while very old patients had the highest prevalence of heart diseases and AF but lowest proportion of positive family history of vascular diseases. Hypertension and DM were equally frequent among three groups. Conclusion. Our study showed that vascular risk factors had a specific age and gender distribution pattern in Chinese IS patients. Secondary prevention strategy should emphasize on the control of different risk factors based on patient’s age and gender.

The Bayesian Covariance Lasso.

Science.gov (United States)

Khondker, Zakaria S; Zhu, Hongtu; Chu, Haitao; Lin, Weili; Ibrahim, Joseph G

2013-04-01

Estimation of sparse covariance matrices and their inverse subject to positive definiteness constraints has drawn a lot of attention in recent years. The abundance of high-dimensional data, where the sample size ( n ) is less than the dimension ( d ), requires shrinkage estimation methods since the maximum likelihood estimator is not positive definite in this case. Furthermore, when n is larger than d but not sufficiently larger, shrinkage estimation is more stable than maximum likelihood as it reduces the condition number of the precision matrix. Frequentist methods have utilized penalized likelihood methods, whereas Bayesian approaches rely on matrix decompositions or Wishart priors for shrinkage. In this paper we propose a new method, called the Bayesian Covariance Lasso (BCLASSO), for the shrinkage estimation of a precision (covariance) matrix. We consider a class of priors for the precision matrix that leads to the popular frequentist penalties as special cases, develop a Bayes estimator for the precision matrix, and propose an efficient sampling scheme that does not precalculate boundaries for positive definiteness. The proposed method is permutation invariant and performs shrinkage and estimation simultaneously for non-full rank data. Simulations show that the proposed BCLASSO performs similarly as frequentist methods for non-full rank data.

Structural covariance and cortical reorganisation in schizophrenia: a MRI-based morphometric study.

Science.gov (United States)

Palaniyappan, Lena; Hodgson, Olha; Balain, Vijender; Iwabuchi, Sarina; Gowland, Penny; Liddle, Peter

2018-05-06

In patients with schizophrenia, distributed abnormalities are observed in grey matter volume. A recent hypothesis posits that these distributed changes are indicative of a plastic reorganisation process occurring in response to a functional defect in neuronal information transmission. We investigated the structural covariance across various brain regions in early-stage schizophrenia to determine if indeed the observed patterns of volumetric loss conform to a coordinated pattern of structural reorganisation. Structural magnetic resonance imaging scans were obtained from 40 healthy adults and 41 age, gender and parental socioeconomic status matched patients with schizophrenia. Volumes of grey matter tissue were estimated at the regional level across 90 atlas-based parcellations. Group-level structural covariance was studied using a graph theoretical framework. Patients had distributed reduction in grey matter volume, with high degree of localised covariance (clustering) compared with controls. Patients with schizophrenia had reduced centrality of anterior cingulate and insula but increased centrality of the fusiform cortex, compared with controls. Simulating targeted removal of highly central nodes resulted in significant loss of the overall covariance patterns in patients compared with controls. Regional volumetric deficits in schizophrenia are not a result of random, mutually independent processes. Our observations support the occurrence of a spatially interconnected reorganisation with the systematic de-escalation of conventional 'hub' regions. This raises the question of whether the morphological architecture in schizophrenia is primed for compensatory functions, albeit with a high risk of inefficiency.

Galaxy-galaxy lensing estimators and their covariance properties

Science.gov (United States)

Singh, Sukhdeep; Mandelbaum, Rachel; Seljak, Uroš; Slosar, Anže; Vazquez Gonzalez, Jose

2017-11-01

We study the covariance properties of real space correlation function estimators - primarily galaxy-shear correlations, or galaxy-galaxy lensing - using SDSS data for both shear catalogues and lenses (specifically the BOSS LOWZ sample). Using mock catalogues of lenses and sources, we disentangle the various contributions to the covariance matrix and compare them with a simple analytical model. We show that not subtracting the lensing measurement around random points from the measurement around the lens sample is equivalent to performing the measurement using the lens density field instead of the lens overdensity field. While the measurement using the lens density field is unbiased (in the absence of systematics), its error is significantly larger due to an additional term in the covariance. Therefore, this subtraction should be performed regardless of its beneficial effects on systematics. Comparing the error estimates from data and mocks for estimators that involve the overdensity, we find that the errors are dominated by the shape noise and lens clustering, which empirically estimated covariances (jackknife and standard deviation across mocks) that are consistent with theoretical estimates, and that both the connected parts of the four-point function and the supersample covariance can be neglected for the current levels of noise. While the trade-off between different terms in the covariance depends on the survey configuration (area, source number density), the diagnostics that we use in this work should be useful for future works to test their empirically determined covariances.

Galaxy–galaxy lensing estimators and their covariance properties

International Nuclear Information System (INIS)

Singh, Sukhdeep; Mandelbaum, Rachel; Seljak, Uros; Slosar, Anze; Gonzalez, Jose Vazquez

2017-01-01

Here, we study the covariance properties of real space correlation function estimators – primarily galaxy–shear correlations, or galaxy–galaxy lensing – using SDSS data for both shear catalogues and lenses (specifically the BOSS LOWZ sample). Using mock catalogues of lenses and sources, we disentangle the various contributions to the covariance matrix and compare them with a simple analytical model. We show that not subtracting the lensing measurement around random points from the measurement around the lens sample is equivalent to performing the measurement using the lens density field instead of the lens overdensity field. While the measurement using the lens density field is unbiased (in the absence of systematics), its error is significantly larger due to an additional term in the covariance. Therefore, this subtraction should be performed regardless of its beneficial effects on systematics. Comparing the error estimates from data and mocks for estimators that involve the overdensity, we find that the errors are dominated by the shape noise and lens clustering, which empirically estimated covariances (jackknife and standard deviation across mocks) that are consistent with theoretical estimates, and that both the connected parts of the four-point function and the supersample covariance can be neglected for the current levels of noise. While the trade-off between different terms in the covariance depends on the survey configuration (area, source number density), the diagnostics that we use in this work should be useful for future works to test their empirically determined covariances.

Age- and Gender-Specific Prevalence of Cardiovascular Risk Factors in 40 102 Patients With First-Ever Ischemic Stroke A Nationwide Danish Study

DEFF Research Database (Denmark)

Andersen, Klaus Kaae; Andersen, Z. J.; Olsen, T. S.

2010-01-01

Background and Purpose—We describe the prevalence of cardiovascular risk factors at stroke onset in men and women of all ages. Methods—A registry started in 2001, designed to register all hospitalized stroke patients in Denmark, now holds 40 102 patients with first-ever ischemic stroke. Patients...... the independent effect of gender and age on prevalence of cardiovascular risk factors and calculated age and gender-specific prevalence rates for each risk factor. Results—The register contained 47.9% women and 52.1% men. Men had more often diabetes mellitus, previous myocardial infarction, intermittent arterial...... claudication, and over the limit alcohol consumption. Women had more often hypertension and obesity. Atrial fibrillation and smoking were equally frequent in both genders. Age stratification revealed that the lifestyle cardiovascular risk factors smoking, alcohol, and obesity were more common in the younger...

Treatment Effects with Many Covariates and Heteroskedasticity

DEFF Research Database (Denmark)

Cattaneo, Matias D.; Jansson, Michael; Newey, Whitney K.

The linear regression model is widely used in empirical work in Economics. Researchers often include many covariates in their linear model specification in an attempt to control for confounders. We give inference methods that allow for many covariates and heteroskedasticity. Our results...

Asthma and chemical hypersensitivity: prevalence, etiology, and age of onset.

Science.gov (United States)

Caress, S M; Steinemann, A C

2009-02-01

This study investigates asthma's national prevalence and potential overlap with chemical hypersensitivity. It also examines asthma's etiology, age of onset, and demographic characteristics. Data were collected from a geographically weighted random sample of the continental U.S. (1058 cases), in four seasonal cohorts (2005-2006). The study found that 12.9% of the sample report asthma, 11.6% report chemical hypersensitivity, and 31.4% of those with asthma report chemical hypersensitivity. Among asthmatics, 38% report irritation from scented products, 37.2% report health problems from air fresheners, and 13.6% report their asthma was caused by toxic exposure. Asthma cases affected each racial/ethic group in roughly the same proportion, with nearly 50% classified as childhood onset.

Model selection for marginal regression analysis of longitudinal data with missing observations and covariate measurement error.

Science.gov (United States)

Shen, Chung-Wei; Chen, Yi-Hau

2015-10-01

Missing observations and covariate measurement error commonly arise in longitudinal data. However, existing methods for model selection in marginal regression analysis of longitudinal data fail to address the potential bias resulting from these issues. To tackle this problem, we propose a new model selection criterion, the Generalized Longitudinal Information Criterion, which is based on an approximately unbiased estimator for the expected quadratic error of a considered marginal model accounting for both data missingness and covariate measurement error. The simulation results reveal that the proposed method performs quite well in the presence of missing data and covariate measurement error. On the contrary, the naive procedures without taking care of such complexity in data may perform quite poorly. The proposed method is applied to data from the Taiwan Longitudinal Study on Aging to assess the relationship of depression with health and social status in the elderly, accommodating measurement error in the covariate as well as missing observations. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

PREVALENCE OF AMOEBIC LIVER ABSCESS IN RELATION TO SEASON, AGE AND SEX

Directory of Open Access Journals (Sweden)

Valluri Satya

2015-04-01

Full Text Available Amoebic liver abscess is one of the important diseases in tropical third world counties, especially in certain areas where the people drink Toddy an alcoholic beverage extacted from palm trees, it ’s available in certain seasons , in these seasons especially late summer to early rainy months the prevalence of Amoebic live r abscess is high, young to middle aged men are more affected than women, since there are many factors why the women are less likely get this disease.

Prevalence of hormone replacement therapy in a sample of middle-aged women

DEFF Research Database (Denmark)

Pedersen, S H; Jeune, B

1988-01-01

A survey based on a postal questionnaire sent to a random sample of Danish women aged 40-59 yr living on the island of Fünen (n = 401, response rate = 79%) revealed that the overall prevalence of the use of hormone replacement therapy (HRT) was 16%, the highest rate being in the 50-54 age group (21......%). Among post-menopausal women the rate was 21% and it was highest of all (37%) in those who had undergone an artificial menopause. The median age at the start of treatment was 44.3 yr among the artificial menopause and 48.9 yr among the natural menopause subjects. About half of the women were treated...... with natural oestrogen alone and over a third with cyclic natural oestrogen in combination with progestogens. Almost one-third of the women had consulted their doctor about climacteric complaints and two-thirds of these were current or past users of HRT. The women had ambiguous feelings towards HRT...

Empirical Likelihood in Nonignorable Covariate-Missing Data Problems.

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Xie, Yanmei; Zhang, Biao

2017-04-20

Missing covariate data occurs often in regression analysis, which frequently arises in the health and social sciences as well as in survey sampling. We study methods for the analysis of a nonignorable covariate-missing data problem in an assumed conditional mean function when some covariates are completely observed but other covariates are missing for some subjects. We adopt the semiparametric perspective of Bartlett et al. (Improving upon the efficiency of complete case analysis when covariates are MNAR. Biostatistics 2014;15:719-30) on regression analyses with nonignorable missing covariates, in which they have introduced the use of two working models, the working probability model of missingness and the working conditional score model. In this paper, we study an empirical likelihood approach to nonignorable covariate-missing data problems with the objective of effectively utilizing the two working models in the analysis of covariate-missing data. We propose a unified approach to constructing a system of unbiased estimating equations, where there are more equations than unknown parameters of interest. One useful feature of these unbiased estimating equations is that they naturally incorporate the incomplete data into the data analysis, making it possible to seek efficient estimation of the parameter of interest even when the working regression function is not specified to be the optimal regression function. We apply the general methodology of empirical likelihood to optimally combine these unbiased estimating equations. We propose three maximum empirical likelihood estimators of the underlying regression parameters and compare their efficiencies with other existing competitors. We present a simulation study to compare the finite-sample performance of various methods with respect to bias, efficiency, and robustness to model misspecification. The proposed empirical likelihood method is also illustrated by an analysis of a data set from the US National Health and

Prevalence of cardiovascular risk factors and the metabolic syndrome in middle-aged men and women in Gothenburg, Sweden

Directory of Open Access Journals (Sweden)

Johansson Saga

2008-12-01

Full Text Available Abstract Background Random samples of 50-year-old men living in Gothenburg have been examined every 10th year since 1963 with a focus on cardiovascular risk factors. The aims of the study were to acquire up-to-date information about risk factors in the fifth cohort of 50-year-old men and women, to re-examine those who were 50 years of age in 1993, and to analyse the prevalence of the metabolic syndrome (MetSyn using different definitions. Methods A random sample of men and women born in 1953 were examined in 2003–2004 for cardiovascular risk factors. Men born in 1943 and that participated in the examination in 1993 were also invited. Descriptive statistics were calculated. Results The participation rate among men and women born in 1953 was 60 and 67% respectively. Among men born in 1943, the participation rate was 87%. The prevalence of obesity was from 15 to 17% (body mass index, BMI ≥ 30 in the three samples. The prevalence of known diabetes was 4% among the 50-year-old men and 6% among the 60-year-old men, and 2% among the women. Increased fasting plasma glucose varied substantially from 4 to 33% depending on cut-off level and gender. Mean cholesterol was 5.4 to 5.5 mmol/l. Smoking was more common among women aged 50 (26% than among men aged 50 (22% and 60 years (15%. The prevalence of the MetSyn varied with the definition used: from 10 to 15.8% among the women, from 16.1 to 26% among 50-year-old men, and from 19.9 to 35% among the 60-year-old men. Only 5% of the men and women had no risk factors. Conclusion This study provides up-to-date information about the prevalence of cardiovascular risk factors and the MetSyn in middle-aged Swedish men and women. Different definitions of the MetSyn create confusion regarding which definition to use.

Cosmic censorship conjecture revisited: covariantly

International Nuclear Information System (INIS)

Hamid, Aymen I M; Goswami, Rituparno; Maharaj, Sunil D

2014-01-01

In this paper we study the dynamics of the trapped region using a frame independent semi-tetrad covariant formalism for general locally rotationally symmetric (LRS) class II spacetimes. We covariantly prove some important geometrical results for the apparent horizon, and state the necessary and sufficient conditions for a singularity to be locally naked. These conditions bring out, for the first time in a quantitative and transparent manner, the importance of the Weyl curvature in deforming and delaying the trapped region during continual gravitational collapse, making the central singularity locally visible. (paper)

Abnormalities in the structural covariance of emotion regulation networks in major depressive disorder.

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Wu, Huawang; Sun, Hui; Wang, Chao; Yu, Lin; Li, Yilan; Peng, Hongjun; Lu, Xiaobing; Hu, Qingmao; Ning, Yuping; Jiang, Tianzi; Xu, Jinping; Wang, Jiaojian

2017-01-01

Major depressive disorder (MDD) is a common psychiatric disorder that is characterized by cognitive deficits and affective symptoms. To date, an increasing number of neuroimaging studies have focused on emotion regulation and have consistently shown that emotion dysregulation is one of the central features and underlying mechanisms of MDD. Although gray matter morphological abnormalities in regions within emotion regulation networks have been identified in MDD, the interactions and relationships between these gray matter structures remain largely unknown. Thus, in this study, we adopted a structural covariance method based on gray matter volume to investigate the brain morphological abnormalities within the emotion regulation networks in a large cohort of 65 MDD patients and 65 age- and gender-matched healthy controls. A permutation test with p covariance connectivity strengths between MDD patients and healthy controls. The structural covariance analysis revealed an increased correlation strength of gray matter volume between the left angular gyrus and the left amygdala and between the right angular gyrus and the right amygdala, as well as a decreased correlation strength of the gray matter volume between the right angular gyrus and the posterior cingulate cortex in MDD. Our findings support the notion that emotion dysregulation is an underlying mechanism of MDD by revealing disrupted structural covariance patterns in the emotion regulation network. Copyright © 2016 Elsevier Ltd. All rights reserved.

Language Ability Predicts Cortical Structure and Covariance in Boys with Autism Spectrum Disorder.

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Sharda, Megha; Foster, Nicholas E V; Tryfon, Ana; Doyle-Thomas, Krissy A R; Ouimet, Tia; Anagnostou, Evdokia; Evans, Alan C; Zwaigenbaum, Lonnie; Lerch, Jason P; Lewis, John D; Hyde, Krista L

2017-03-01

There is significant clinical heterogeneity in language and communication abilities of individuals with Autism Spectrum Disorders (ASD). However, no consistent pathology regarding the relationship of these abilities to brain structure has emerged. Recent developments in anatomical correlation-based approaches to map structural covariance networks (SCNs), combined with detailed behavioral characterization, offer an alternative for studying these relationships. In this study, such an approach was used to study the integrity of SCNs of cortical thickness and surface area associated with language and communication, in 46 high-functioning, school-age children with ASD compared with 50 matched, typically developing controls (all males) with IQ > 75. Findings showed that there was alteration of cortical structure and disruption of fronto-temporal cortical covariance in ASD compared with controls. Furthermore, in an analysis of a subset of ASD participants, alterations in both cortical structure and covariance were modulated by structural language ability of the participants, but not communicative function. These findings indicate that structural language abilities are related to altered fronto-temporal cortical covariance in ASD, much more than symptom severity or cognitive ability. They also support the importance of better characterizing ASD samples while studying brain structure and for better understanding individual differences in language and communication abilities in ASD. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Incidence and prevalence of diabetes in children aged Fiji, 2001-2012.

Science.gov (United States)

Ogle, Graham D; Morrison, Melinda K; Silink, Martin; Taito, Rigamoto S

2016-05-01

Determine the incidence and prevalence of diabetes in children Fiji. Data on all new cases from 2001 to 2012 was collected from the three paediatric diabetes services through the International Diabetes Federation Life for a Child Program. There was no formal secondary ascertainment source, however the medical community is small and all known cases are believed to be included. Forty-two children aged Fiji is very low. Furthermore, its occurrence is markedly more frequent in Indo-Fijians than in native Fijians. Type 2 and neonatal diabetes also occur. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Evaluation of covariance in theoretical calculation of nuclear data

International Nuclear Information System (INIS)

Kikuchi, Yasuyuki

1981-01-01

Covariances of the cross sections are discussed on the statistical model calculations. Two categories of covariance are discussed: One is caused by the model approximation and the other by the errors in the model parameters. As an example, the covariances are calculated for 100 Ru. (author)

Updated Covariance Processing Capabilities in the AMPX Code System

International Nuclear Information System (INIS)

Wiarda, Dorothea; Dunn, Michael E.

2007-01-01

A concerted effort is in progress within the nuclear data community to provide new cross-section covariance data evaluations to support sensitivity/uncertainty analyses of fissionable systems. The objective of this work is to update processing capabilities of the AMPX library to process the latest Evaluated Nuclear Data File (ENDF)/B formats to generate covariance data libraries for radiation transport software such as SCALE. The module PUFF-IV was updated to allow processing of new ENDF covariance formats in the resolved resonance region. In the resolved resonance region, covariance matrices are given in terms of resonance parameters, which need to be processed into covariance matrices with respect to the group-averaged cross-section data. The parameter covariance matrix can be quite large if the evaluation has many resonances. The PUFF-IV code has recently been used to process an evaluation of 235U, which was prepared in collaboration between Oak Ridge National Laboratory and Los Alamos National Laboratory.

Socioeconomic status and overweight prevalence in polish adolescents: the impact of single factors and a complex index of socioeconomic status in respect to age and sex.

Science.gov (United States)

Kowalkowska, Joanna; Wadolowska, Lidia; Weronika Wuenstel, Justyna; Słowińska, Małgorzata Anna; Niedźwiedzka, Ewa

2014-07-01

The aim of this study was to analyze the association between overweight prevalence and socioeconomic status (SES) measured by complex SES index and single SES factors in Polish adolescents in respect to age and sex. This cross-sectional study was conducted in 2010-2011. A total of 1,176 adolescents aged 13.0-18.9 years were included. The respondents were students of junior-high and high schools from northern, eastern and central Poland. Quota sampling by sex and age was used. The SES was determined by: place of residence, self-declared economic situation, and parental education level. Respondents with low, average or high SES index (SESI) were identified. The level of overweight was assessed using Polish and international standards. The odds ratio (OR) for overweight prevalence in the oldest girls (aged 17.0-18.9 years) with high SESI was 0.34 (95%CI:0.13-0.92; P single SES factors were not significant for overweight prevalence. The relationship between socioeconomic status and prevalence of overweight was related to sex and age. The high socioeconomic status strongly lowered the risk of overweight prevalence in the oldest girls, but not in boys, irrespective of age. Maternal education level lowered risk of overweight prevalence in girls.

Inverse association between altitude and obesity: A prevalence study among Andean and low-altitude adult individuals of Peru

Science.gov (United States)

Woolcott, Orison O.; Gutierrez, Cesar; Castillo, Oscar A.; Elashoff, Robert M.; Stefanovski, Darko; Bergman, Richard N.

2015-01-01

Objective To determine the association between altitude and obesity in a nationally representative sample of the Peruvian adult population. Design and Methods This is a cross-sectional analysis of publicly available data from the Food and Nutrition National Center (CENAN, Peru), period 2009-2010. Prevalence ratio of obesity and abdominal obesity was determined as a measure of association. Obesity and abdominal obesity were diagnosed based on direct anthropometric measurements. Results The final dataset consisted of 31,549 individuals ≥20 years old. The prevalence ratio of obesity was as follows: 1.00 between 0–499 m (reference category), 1.00 (95% confidence interval 0.87-1.16) between 500–1,499 m, 0.74 (0.63-0.86) between 1,500–2,999, and 0.54 (0.45-0.64) at ≥3,000 m, adjusting for age, sex, self-reported physical activity, out-migration rate, urbanization, poverty, education, and geographical latitude and longitude. In the same order, the adjusted prevalence ratio of abdominal obesity was 1.00, 1.01 (0.94-1.07), 0.93 (0.87-0.99), and 0.89 (0.82-0.95), respectively. We found an interaction between altitude and sex and between altitude and age (P<0.001, for both interactions) on the association with obesity and abdominal obesity. Conclusions Among Peruvian adult individuals, we found an inverse association between altitude and obesity, adjusting for multiple covariates. This adjusted association varied by sex and age. PMID:26935008

Inverse association between altitude and obesity: A prevalence study among andean and low-altitude adult individuals of Peru.

Science.gov (United States)

Woolcott, Orison O; Gutierrez, Cesar; Castillo, Oscar A; Elashoff, Robert M; Stefanovski, Darko; Bergman, Richard N

2016-04-01

To determine the association between altitude and obesity in a nationally representative sample of the Peruvian adult population. This is a cross-sectional analysis of publicly available data from the Food and Nutrition National Center (CENAN, Peru), period 2009-2010. The Prevalence ratio of obesity and abdominal obesity was determined as a measure of association. Obesity and abdominal obesity were diagnosed based on direct anthropometric measurements. The final data set consisted of 31,549 individuals ≥20 years old. The prevalence ratio of obesity was as follows: 1.00 between 0 and 499 m (reference category), 1.00 (95% confidence interval 0.87-1.16) between 500-1,499 m, 0.74 (0.63-0.86) between 1,500-2,999 m, and 0.54 (0.45-0.64) at ≥3,000 m, adjusting for age, sex, self-reported physical activity, out-migration rate, urbanization, poverty, education, and geographical latitude and longitude. In the same order, the adjusted prevalence ratio of abdominal obesity was 1.00, 1.01 (0.94-1.07), 0.93 (0.87-0.99), and 0.89 (0.82-0.95), respectively. We found an interaction between altitude and sex and between altitude and age (P association with obesity and abdominal obesity. Among Peruvian adult individuals, we found an inverse association between altitude and obesity, adjusting for multiple covariates. This adjusted association varied by sex and age. © 2016 The Obesity Society.

Large Covariance Estimation by Thresholding Principal Orthogonal Complements

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Fan, Jianqing; Liao, Yuan; Mincheva, Martina

2012-01-01

This paper deals with the estimation of a high-dimensional covariance with a conditional sparsity structure and fast-diverging eigenvalues. By assuming sparse error covariance matrix in an approximate factor model, we allow for the presence of some cross-sectional correlation even after taking out common but unobservable factors. We introduce the Principal Orthogonal complEment Thresholding (POET) method to explore such an approximate factor structure with sparsity. The POET estimator includes the sample covariance matrix, the factor-based covariance matrix (Fan, Fan, and Lv, 2008), the thresholding estimator (Bickel and Levina, 2008) and the adaptive thresholding estimator (Cai and Liu, 2011) as specific examples. We provide mathematical insights when the factor analysis is approximately the same as the principal component analysis for high-dimensional data. The rates of convergence of the sparse residual covariance matrix and the conditional sparse covariance matrix are studied under various norms. It is shown that the impact of estimating the unknown factors vanishes as the dimensionality increases. The uniform rates of convergence for the unobserved factors and their factor loadings are derived. The asymptotic results are also verified by extensive simulation studies. Finally, a real data application on portfolio allocation is presented. PMID:24348088

Complexity of low-frequency blood oxygen level-dependent fluctuations covaries with local connectivity.

Science.gov (United States)

Anderson, Jeffrey S; Zielinski, Brandon A; Nielsen, Jared A; Ferguson, Michael A

2014-04-01

Very low-frequency blood oxygen level-dependent (BOLD) fluctuations have emerged as a valuable tool for describing brain anatomy, neuropathology, and development. Such fluctuations exhibit power law frequency dynamics, with largest amplitude at lowest frequencies. The biophysical mechanisms generating such fluctuations are poorly understood. Using publicly available data from 1,019 subjects of age 7-30, we show that BOLD fluctuations exhibit temporal complexity that is linearly related to local connectivity (regional homogeneity), consistently and significantly covarying across subjects and across gray matter regions. This relationship persisted independently of covariance with gray matter density or standard deviation of BOLD signal. During late neurodevelopment, BOLD fluctuations were unchanged with age in association cortex while becoming more random throughout the rest of the brain. These data suggest that local interconnectivity may play a key role in establishing the complexity of low-frequency BOLD fluctuations underlying functional magnetic resonance imaging connectivity. Stable low-frequency power dynamics may emerge through segmentation and integration of connectivity during development of distributed large-scale brain networks. Copyright © 2013 Wiley Periodicals, Inc.

Prevalence of rheumatoid arthritis in persons 60 years of age and older in the United States: effect of different methods of case classification.

Science.gov (United States)

Rasch, Elizabeth K; Hirsch, Rosemarie; Paulose-Ram, Ryne; Hochberg, Marc C

2003-04-01

To determine prevalence estimates for rheumatoid arthritis (RA) in noninstitutionalized older adults in the US. Prevalence estimates were compared using 3 different classification methods based on current classification criteria for RA. Data from the Third National Health and Nutrition Examination Survey (NHANES-III) were used to generate prevalence estimates by 3 classification methods in persons 60 years of age and older (n = 5,302). Method 1 applied the "n of k" rule, such that subjects who met 3 of 6 of the American College of Rheumatology (ACR) 1987 criteria were classified as having RA (data from hand radiographs were not available). In method 2, the ACR classification tree algorithm was applied. For method 3, medication data were used to augment case identification via method 2. Population prevalence estimates and 95% confidence intervals (95% CIs) were determined using the 3 methods on data stratified by sex, race/ethnicity, age, and education. Overall prevalence estimates using the 3 classification methods were 2.03% (95% CI 1.30-2.76), 2.15% (95% CI 1.43-2.87), and 2.34% (95% CI 1.66-3.02), respectively. The prevalence of RA was generally greater in the following groups: women, Mexican Americans, respondents with less education, and respondents who were 70 years of age and older. The prevalence of RA in persons 60 years of age and older is approximately 2%, representing the proportion of the US elderly population who will most likely require medical intervention because of disease activity. Different classification methods yielded similar prevalence estimates, although detection of RA was enhanced by incorporation of data on use of prescription medications, an important consideration in large population surveys.

Associations of sleep duration and prediabetes prevalence in a middle-aged and elderly Chinese population with regard to age and hypertension: The China Health and Retirement Longitudinal Study baseline survey.

Science.gov (United States)

Yan, Mingming; Fu, Zhen; Qin, Tingting; Wu, Nanjin; Lv, Yalan; Wei, Qinyun; Jiang, Hongwei; Yin, Ping

2018-03-24

The aim of the present study was to examine the age-specific associations between self-reported sleep duration and prevalent prediabetes in middle-aged and elderly Chinese with or without hypertension. In all, 2985 Chinese adults aged ≥45 years from the China Health and Retirement Longitudinal Study (CHARLS) baseline survey were selected for analysis. Sleep duration was assessed by structured questionnaires and then categorized into three groups (≤6, 6-8, and >8 h). The prevalence of prediabetes was defined using fasting plasma glucose (100-125 mg/dL) and/or HbA1c (5.7%-6.4%) in conjunction with no previous diabetes diagnosis and no antidiabetic medication. Relationships between self-reported sleep duration and prevalent prediabetes were examined according to age (45-60 years, middle-aged; ≥60 years, elderly) and hypertension groups using Poisson regression models to estimate prevalence ratios (PRs) and 95% confidence intervals (CI). Compared with the reference group of 6-8 h sleep/night, short sleep (≤6 h/night) was associated with an increased risk of prediabetes in the whole sample (PR 1.09, 95% CI 1.01-1.17) after adjusting for confounders. This association was more pronounced in elderly participants without hypertension (PR 1.27, 95% CI 1.07-1.51). This study suggests that participants with a short sleep period are at a moderately increased risk of prediabetes, particularly in elderly subjects without hypertension. Aging and hypertension may be important in the relationship between short sleep and impaired glucose metabolism. © 2018 Ruijin Hospital, Shanghai Jiaotong University School of Medicine and John Wiley & Sons Australia, Ltd.

Impact of the 235U Covariance Data in Benchmark Calculations

International Nuclear Information System (INIS)

Leal, Luiz C.; Mueller, D.; Arbanas, G.; Wiarda, D.; Derrien, H.

2008-01-01

The error estimation for calculated quantities relies on nuclear data uncertainty information available in the basic nuclear data libraries such as the U.S. Evaluated Nuclear Data File (ENDF/B). The uncertainty files (covariance matrices) in the ENDF/B library are generally obtained from analysis of experimental data. In the resonance region, the computer code SAMMY is used for analyses of experimental data and generation of resonance parameters. In addition to resonance parameters evaluation, SAMMY also generates resonance parameter covariance matrices (RPCM). SAMMY uses the generalized least-squares formalism (Bayes method) together with the resonance formalism (R-matrix theory) for analysis of experimental data. Two approaches are available for creation of resonance-parameter covariance data. (1) During the data-evaluation process, SAMMY generates both a set of resonance parameters that fit the experimental data and the associated resonance-parameter covariance matrix. (2) For existing resonance-parameter evaluations for which no resonance-parameter covariance data are available, SAMMY can retroactively create a resonance-parameter covariance matrix. The retroactive method was used to generate covariance data for 235U. The resulting 235U covariance matrix was then used as input to the PUFF-IV code, which processed the covariance data into multigroup form, and to the TSUNAMI code, which calculated the uncertainty in the multiplication factor due to uncertainty in the experimental cross sections. The objective of this work is to demonstrate the use of the 235U covariance data in calculations of critical benchmark systems

Impact of the 235U covariance data in benchmark calculations

International Nuclear Information System (INIS)

Leal, Luiz; Mueller, Don; Arbanas, Goran; Wiarda, Dorothea; Derrien, Herve

2008-01-01

The error estimation for calculated quantities relies on nuclear data uncertainty information available in the basic nuclear data libraries such as the U.S. Evaluated Nuclear Data File (ENDF/B). The uncertainty files (covariance matrices) in the ENDF/B library are generally obtained from analysis of experimental data. In the resonance region, the computer code SAMMY is used for analyses of experimental data and generation of resonance parameters. In addition to resonance parameters evaluation, SAMMY also generates resonance parameter covariance matrices (RPCM). SAMMY uses the generalized least-squares formalism (Bayes' method) together with the resonance formalism (R-matrix theory) for analysis of experimental data. Two approaches are available for creation of resonance-parameter covariance data. (1) During the data-evaluation process, SAMMY generates both a set of resonance parameters that fit the experimental data and the associated resonance-parameter covariance matrix. (2) For existing resonance-parameter evaluations for which no resonance-parameter covariance data are available, SAMMY can retroactively create a resonance-parameter covariance matrix. The retroactive method was used to generate covariance data for 235 U. The resulting 235 U covariance matrix was then used as input to the PUFF-IV code, which processed the covariance data into multigroup form, and to the TSUNAMI code, which calculated the uncertainty in the multiplication factor due to uncertainty in the experimental cross sections. The objective of this work is to demonstrate the use of the 235 U covariance data in calculations of critical benchmark systems. (authors)

Parameters of the covariance function of galaxies

International Nuclear Information System (INIS)

Fesenko, B.I.; Onuchina, E.V.

1988-01-01

The two-point angular covariance functions for two samples of galaxies are considered using quick methods of analysis. It is concluded that in the previous investigations the amplitude of the covariance function in the Lick counts was overestimated and the rate of decrease of the function underestimated

Generally covariant gauge theories

International Nuclear Information System (INIS)

Capovilla, R.

1992-01-01

A new class of generally covariant gauge theories in four space-time dimensions is investigated. The field variables are taken to be a Lie algebra valued connection 1-form and a scalar density. Modulo an important degeneracy, complex [euclidean] vacuum general relativity corresponds to a special case in this class. A canonical analysis of the generally covariant gauge theories with the same gauge group as general relativity shows that they describe two degrees of freedom per space point, qualifying therefore as a new set of neighbors of general relativity. The modification of the algebra of the constraints with respect to the general relativity case is computed; this is used in addressing the question of how general relativity stands out from its neighbors. (orig.)

Prevalence and Characteristics of Autism Spectrum Disorder Among Children Aged 8 Years--Autism and Developmental Disabilities Monitoring Network, 11 Sites, United States, 2012.

Science.gov (United States)

Christensen, Deborah L; Baio, Jon; Van Naarden Braun, Kim; Bilder, Deborah; Charles, Jane; Constantino, John N; Daniels, Julie; Durkin, Maureen S; Fitzgerald, Robert T; Kurzius-Spencer, Margaret; Lee, Li-Ching; Pettygrove, Sydney; Robinson, Cordelia; Schulz, Eldon; Wells, Chris; Wingate, Martha S; Zahorodny, Walter; Yeargin-Allsopp, Marshalyn

2016-04-01

Autism spectrum disorder (ASD). 2012. The Autism and Developmental Disabilities Monitoring (ADDM) Network is an active surveillance system that provides estimates of the prevalence and characteristics of ASD among children aged 8 years whose parents or guardians reside in 11 ADDM Network sites in the United States (Arkansas, Arizona, Colorado, Georgia, Maryland, Missouri, New Jersey, North Carolina, South Carolina, Utah, and Wisconsin). Surveillance to determine ASD case status is conducted in two phases. The first phase consists of screening and abstracting comprehensive evaluations performed by professional service providers in the community. Data sources identified for record review are categorized as either 1) education source type, including developmental evaluations to determine eligibility for special education services or 2) health care source type, including diagnostic and developmental evaluations. The second phase involves the review of all abstracted evaluations by trained clinicians to determine ASD surveillance case status. A child meets the surveillance case definition for ASD if one or more comprehensive evaluations of that child completed by a qualified professional describes behaviors that are consistent with the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision diagnostic criteria for any of the following conditions: autistic disorder, pervasive developmental disorder-not otherwise specified (including atypical autism), or Asperger disorder. This report provides ASD prevalence estimates for children aged 8 years living in catchment areas of the ADDM Network sites in 2012, overall and stratified by sex, race/ethnicity, and the type of source records (education and health records versus health records only). In addition, this report describes the proportion of children with ASD with a score consistent with intellectual disability on a standardized intellectual ability test, the age at which the earliest known

[Prevalence of metabolic syndrome in indigenous people over 40 years of age in Rio Grande do Sul, Brazil].

Science.gov (United States)

da Rocha, Ana Karina Silva; Bós, Angelo José Gonçalves; Huttner, Edison; Machado, Denise Cantarelli

2011-01-01

To investigate the prevalence of the metabolic syndrome (MS) among indigenous people older than 40 years of age from two cities in the State of Rio Grande do Sul, southern Brazil. A descriptive, analytic, cross-sectional study was conducted in two municipalities, Porto Alegre and Nonoai, between July and August 2009. A total of 150 indigenous people older than 40 years of age (range: 40-104 years), participated in the study. MS prevalence was determined based on National Cholesterol Education Program - Adult Treatment Panel III criteria. Blood samples and anthropometric data were collected. The participants also answered a questionnaire on eating habits, which was then contrasted to the 10 steps to healthy eating proposed by the World Health Organization and recommended by the Brazilian Ministry of Health. MS prevalence was 65.3%, affecting women more than men (P motivation for healthy behaviors is possibly the best way to manage MS and promote health in a population that is still neglected by public health policies.

Prevalence of endometrial polyps and abnormal uterine bleeding in a Danish population aged 20-74 years

DEFF Research Database (Denmark)

Dreisler, E; Stampe Sorensen, S; Ibsen, P H

2009-01-01

OBJECTIVE: To estimate the prevalence of endometrial polyps and to investigate associated abnormal uterine bleeding in a Danish population aged 20-74 years. METHODS: This was a study of a random selection of women from the Danish Civil Registration System: 1660 women were invited of whom 686 were...... verified polyps were asymptomatic. In asymptomatic premenopausal women the prevalence of polyps was 7.6%, while it was 13% in asymptomatic postmenopausal women. AUB, in particular intermenstrual bleeding, was more frequent among women without polyps (38%). By ultrasound examination, submucosal myomas were...

Prevalence of metabolic syndrome and associated factors in women aged 35 to 65 years who were enrolled in a family health program in Brazil.

Science.gov (United States)

Schmitt, Ana Carolina Basso; Cardoso, Maria Regina Alves; Lopes, Heno; Pereira, Wendry Maria Paixão; Pereira, Elaine Cristina; de Rezende, Debora Aparecida Paccola; Guarizi, Rubia Guibo; Dellu, Mayra Cecilia; Oliveira, Jéssica de Moura; Flauzino, Erika; Blümel, Juan E; Aldrighi, José Mendes

2013-04-01

The aims of this study were to estimate the prevalence of metabolic syndrome among women aged 35 to 65 years and to identify associated factors. This was a cross-sectional study. We randomly selected 581 women (aged 35-65 y) from among those enrolled in a family health program in the city of Pindamonhangaba, Brazil. Metabolic syndrome was identified in accordance with the definition of the National Cholesterol Education Program Adult Treatment Panel III. Health conditions and lifestyle habits were evaluated by a survey, and anthropometric measurements were obtained. The prevalence of metabolic syndrome was estimated, and Poisson regression was used to evaluate the associations between metabolic syndrome `and the factors investigated. The prevalence of metabolic syndrome was 42.2% (95% CI, 38.1-46.2). The most common metabolic syndrome component was abdominal obesity (60.6%), followed by low levels of high-density lipoprotein cholesterol (51.3%), high levels of triglycerides (41.4%), high blood pressure (31.7%), and diabetes (13.9%). The following factors were associated with metabolic syndrome: the 45- to 54-year age group (prevalence ratio, 1.54; 95% CI, 1.08-2.01), the 55- to 65-year age group (prevalence ratio, 3.51; 95% CI, 1.49-3.10), hyperuricemia (prevalence ratio, 2.95; 95% CI, 1.15-1.86), and sleep apnea risk (prevalence ratio, 2.41; 95% CI, 1.16-1.82). We found an inverse association between metabolic syndrome and having had more than 5 years of schooling (prevalence ratio, 0.65; 95% CI, 0.65-1.04). The prevalence of metabolic syndrome is high, and the associated clinical factors are hyperuricemia and risk of sleep apnea.

Nonrelativistic fluids on scale covariant Newton-Cartan backgrounds

Science.gov (United States)

Mitra, Arpita

2017-12-01

The nonrelativistic covariant framework for fields is extended to investigate fields and fluids on scale covariant curved backgrounds. The scale covariant Newton-Cartan background is constructed using the localization of space-time symmetries of nonrelativistic fields in flat space. Following this, we provide a Weyl covariant formalism which can be used to study scale invariant fluids. By considering ideal fluids as an example, we describe its thermodynamic and hydrodynamic properties and explicitly demonstrate that it satisfies the local second law of thermodynamics. As a further application, we consider the low energy description of Hall fluids. Specifically, we find that the gauge fields for scale transformations lead to corrections of the Wen-Zee and Berry phase terms contained in the effective action.

Prevalence of periodontitis among the adolescents aged 15-18 years in Mangalore City: An epidemiological and microbiological study

Directory of Open Access Journals (Sweden)

K Pallavi Nanaiah

2013-01-01

Full Text Available Background: Periodontitis is a group of inflammatory diseases affecting the supporting tissues of the tooth. Both aggressive periodontitis (AP and chronic periodontitis (CP have a multifactorial etiology, with dental plaque as the initiating factor. However, the initiation and progression of periodontitis are influenced by other factors including microbiologic, social and behavioral and systemic and genetic factors. The prevalence of periodontal diseases varies in different regions of the world according to the definition of periodontitis and the study population, and there are indications that they may be more prevalent in developing than in developed countries. Materials and Methods: A cross-sectional study was conducted among the adolescents of 15-18 years of age in Mangalore City. One thousand one hundred students aged 15-18 years were selected for the study from the schools and colleges in Mangalore City using a convenient sampling method. The prevalence of AP and CP were assessed in the study using a community periodontal index. Students who were diagnosed clinically and radiographically were subjected to microbiological examination to confirm AP. Results: A high prevalence of gingivitis and periodontitis was found in students belonging to the lower socioeconomic status group compared with the higher socioeconomic groups, which were associated with poor oral hygiene habits. The prevalence of AP was found to be 0.36% and that of CP was found to be 1.5%. Conclusion: Oral diseases have a significant impact on the social and psychological aspects of an individual′s life. Exposure to risk factors, such as age, low socio-economic status, poor education, low dental care utilization, poor oral hygiene levels, smoking, psychosocial stress and genetic factors are significantly associated with an increased risk of periodontitis among adolescents. Although genetic factors play a major role in periodontitis, the treatment outcome will still be

Deriving Genomic Breeding Values for Residual Feed Intake from Covariance Functions of Random Regression Models

DEFF Research Database (Denmark)

Strathe, Anders B; Mark, Thomas; Nielsen, Bjarne

2014-01-01

Random regression models were used to estimate covariance functions between cumulated feed intake (CFI) and body weight (BW) in 8424 Danish Duroc pigs. Random regressions on second order Legendre polynomials of age were used to describe genetic and permanent environmental curves in BW and CFI...

Pain is prevalent and persisting in cancer survivors: differential factors across age groups.

Science.gov (United States)

Moye, Jennifer; June, Andrea; Martin, Lindsey Ann; Gosian, Jeffrey; Herman, Levi I; Naik, Aanand D

2014-04-01

The Institute of Medicine documents a significant gap in care for long term side effects of cancer treatment, including pain. This paper characterizes age differences in the prevalence and predictive characteristics of pain to guide clinicians in identification and treatment. A sample of 170 adults with head and neck, esophageal, gastric, or colorectal cancers were recruited from two regional Veterans Administration Medical Centers. Face to face interviews were conducted 6, 12, and 18 months after diagnosis with the PROMIS scale to assess pain and PHQ-9 scale to assess depression. Descriptive statistics characterized incidence and prevalence of pain impact and intensity ratings. Multivariate linear hierarchical regression identified clinical characteristics associated with pain in older versus younger age groups. Clinically significant pain was endorsed in one third (32%) of the sample, with younger adults reporting higher levels of the impact of pain on daily activities and work, and also higher pain intensity ratings than older adults. In younger adults, pain ratings were most associated with lower social support and higher depression, as well as advanced cancer stage. In older adults, pain was multifactorial, associated with baseline comorbidities, adjuvant treatment, and both combat post-traumatic stress disorder (PTSD) and depression. Pain is a significant persisting problem for one in three cancer survivors, requiring ongoing assessment, even months later. Important differences in pain's determinants and impact are present by age group. Identification and treatment of pain, as well as associated conditions such as depression, may improve the quality of life in cancer survivors. Published by Elsevier Ltd.

[Prevalence, awareness, status of treatment and control on type 2 diabetes mellitus among Chinese premenopausal women aged 18-49 in 2013].

Science.gov (United States)

Zhao, Y F; Wang, Z Q; Yang, J; Wang, L M; Zhao, Z P; Zeng, X Y; Wang, L H

2018-02-10

Objective: To analyze the rates on prevalence, awareness, status on treatment and control of type 2 diabetes mellitus among Chinese premenopausal women aged 18-49, in 2013. Methods: Data on China Chronic and Non-Communicable Disease Surveillance in year 2013 was used for analysis. Source of data covered 302 surveillance points which were selected by Multi-stage cluster random sampling method that including 176 534 adults over 18 years of age, with 46 674 premenopausal women aged 18-49. Plasma glucose and hemoglobin A1c levels were determined after a 10-hour overnight fast for all the participants, before a 2-hour oral glucose tolerance test was conducted among participants without a self-reported history of diagnosed diabetes. Diabetes was defined according to the 1999 WHO diagnostic criteria-fasting blood glucose level as ≥7.0 mmol/L and/or 2 hours oral glucose tolerance test (OGTT-2 h) level as ≥11.1 mmol/L. After being weighed, according to complex sampling scheme and post-stratification, the sample was used to estimate the rates of prevalence, awareness, treatment and control of type 2 diabetes mellitus by age, education, urban and rural areas, and geographic locations. Results: The overall prevalence of type 2 diabetes mellitus was 5.6% among the Chinese premenopausal women aged 18-49. No statistical difference on the prevalence rates (5.7% and 5.4%, respectively) was seen, between participants from the rural or the urban areas. Prevalence rates in the eastern, central or western geographic areas were 5.8%, 6.2% and 4.4% respectively. The rates of awareness, treatment and control of diabetes appeared as 29.3%, 27.9% and 29.4% in childbearing women aged 18-49. The rate of treatment was 95.4% among those who knew their diabetic situation in childbearing women aged 18-49 years. The control rate of diabetes was 38.9% among those who had taken measures to control glucose, in 18-49-year-old childbearing women. The rate of awareness on diabetes in childbearing

Bayes Factor Covariance Testing in Item Response Models.

Science.gov (United States)

Fox, Jean-Paul; Mulder, Joris; Sinharay, Sandip

2017-12-01

Two marginal one-parameter item response theory models are introduced, by integrating out the latent variable or random item parameter. It is shown that both marginal response models are multivariate (probit) models with a compound symmetry covariance structure. Several common hypotheses concerning the underlying covariance structure are evaluated using (fractional) Bayes factor tests. The support for a unidimensional factor (i.e., assumption of local independence) and differential item functioning are evaluated by testing the covariance components. The posterior distribution of common covariance components is obtained in closed form by transforming latent responses with an orthogonal (Helmert) matrix. This posterior distribution is defined as a shifted-inverse-gamma, thereby introducing a default prior and a balanced prior distribution. Based on that, an MCMC algorithm is described to estimate all model parameters and to compute (fractional) Bayes factor tests. Simulation studies are used to show that the (fractional) Bayes factor tests have good properties for testing the underlying covariance structure of binary response data. The method is illustrated with two real data studies.

The K-Step Spatial Sign Covariance Matrix

NARCIS (Netherlands)

Croux, C.; Dehon, C.; Yadine, A.

2010-01-01

The Sign Covariance Matrix is an orthogonal equivariant estimator of mul- tivariate scale. It is often used as an easy-to-compute and highly robust estimator. In this paper we propose a k-step version of the Sign Covariance Matrix, which improves its e±ciency while keeping the maximal breakdown

On the covariance matrices in the evaluated nuclear data

International Nuclear Information System (INIS)

Corcuera, R.P.

1983-05-01

The implications of the uncertainties of nuclear data on reactor calculations are shown. The concept of variance, covariance and correlation are expressed first by intuitive definitions and then through statistical theory. The format of the covariance data for ENDF/B is explained and the formulas to obtain the multigroup covariances are given. (Author) [pt

Massive data compression for parameter-dependent covariance matrices

Science.gov (United States)

Heavens, Alan F.; Sellentin, Elena; de Mijolla, Damien; Vianello, Alvise

2017-12-01

We show how the massive data compression algorithm MOPED can be used to reduce, by orders of magnitude, the number of simulated data sets which are required to estimate the covariance matrix required for the analysis of Gaussian-distributed data. This is relevant when the covariance matrix cannot be calculated directly. The compression is especially valuable when the covariance matrix varies with the model parameters. In this case, it may be prohibitively expensive to run enough simulations to estimate the full covariance matrix throughout the parameter space. This compression may be particularly valuable for the next generation of weak lensing surveys, such as proposed for Euclid and Large Synoptic Survey Telescope, for which the number of summary data (such as band power or shear correlation estimates) is very large, ∼104, due to the large number of tomographic redshift bins which the data will be divided into. In the pessimistic case where the covariance matrix is estimated separately for all points in an Monte Carlo Markov Chain analysis, this may require an unfeasible 109 simulations. We show here that MOPED can reduce this number by a factor of 1000, or a factor of ∼106 if some regularity in the covariance matrix is assumed, reducing the number of simulations required to a manageable 103, making an otherwise intractable analysis feasible.

Alterations in Anatomical Covariance in the Prematurely Born.

Science.gov (United States)

Scheinost, Dustin; Kwon, Soo Hyun; Lacadie, Cheryl; Vohr, Betty R; Schneider, Karen C; Papademetris, Xenophon; Constable, R Todd; Ment, Laura R

2017-01-01

Preterm (PT) birth results in long-term alterations in functional and structural connectivity, but the related changes in anatomical covariance are just beginning to be explored. To test the hypothesis that PT birth alters patterns of anatomical covariance, we investigated brain volumes of 25 PTs and 22 terms at young adulthood using magnetic resonance imaging. Using regional volumetrics, seed-based analyses, and whole brain graphs, we show that PT birth is associated with reduced volume in bilateral temporal and inferior frontal lobes, left caudate, left fusiform, and posterior cingulate for prematurely born subjects at young adulthood. Seed-based analyses demonstrate altered patterns of anatomical covariance for PTs compared with terms. PTs exhibit reduced covariance with R Brodmann area (BA) 47, Broca's area, and L BA 21, Wernicke's area, and white matter volume in the left prefrontal lobe, but increased covariance with R BA 47 and left cerebellum. Graph theory analyses demonstrate that measures of network complexity are significantly less robust in PTs compared with term controls. Volumes in regions showing group differences are significantly correlated with phonological awareness, the fundamental basis for reading acquisition, for the PTs. These data suggest both long-lasting and clinically significant alterations in the covariance in the PTs at young adulthood. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Age associated differences in prevalence of individual rotterdam criteria and metabolic risk factors during reproductive age in 446 caucasian women with polycystic ovary syndrome

DEFF Research Database (Denmark)

Glintborg, D; Mumm, H; Ravn, P

2012-01-01

, fasting lipids, insulin, glucose), transvaginal ultrasound, oral glucose tolerance tests (OGTT) (n=234), and ACTH tests (n=201). BMI, waist, Ferriman-Gallwey score, blood pressure, and lipid profile were higher in older vs. younger age groups whereas androgen levels were lower. Measures of insulin...... resistance were unchanged between age groups, but glucose levels were significantly higher in older age groups. Rotterdam criteria: The prevalence of PCO and biochemical hyperandrogenism decreased in the oldest age group whereas clinical hyperandrogenism increased. Young patients are characterized by PCO...... and biochemical hyperandrogenism, whereas older patients are more obese with more severe hirsutism and more cardiovascular and metabolic risk factors....

Is the prevalence of overweight reducing at age 5–6 years? Ten years data collection in ASL Milano 2

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Brambilla Paolo

2012-06-01

Full Text Available Abstract Background Prevalence of overweight and obesity has been reported as high even in preschool age children. However, recent international reports suggest that prevalence is now plateauing in pediatric age. Up to now no data are available on prevalence changes in Italy in the new Millennium. Aim of the study was to describe changes of overweight and obesity prevalence during the last decade in 5–6 y children in a large Health Unit in Northern Italy. Methods The Health Report n 8, used at 5–6 y and containing body mass index (BMI, was utilized for prevalence estimation from 2002 to 2011 according to BMI cut-offs proposed by Cole et al. Results Overweight and obese children progressively decreased during the study period (p 0.0002 with a minimum observed in 2011, showing a cumulative frequency of 23.1% in 2002 and of 16.6% in 2011 (−6.5%. Mean BMI values progressively decreased with time so that BMI values in 2010–2011 were significantly lower than in 2002–2003 (p  Conclusions This is the first report suggesting a possible decrease of overweight and obesity at 5–6 y in Italy in the last decade. As the study focused only on 5–6 y children, we don’t know if the true overweight prevalence in pediatric age is really reducing or the starting age of overweight status is simply delayed. The higher risk for malnutrition, both for excess or defect, found in our Area in not Italian children respect to Italian peers, strongly suggests to implement weight control especially for those children. Our finding needs further confirm studies but seems encouraging for true prevention of such condition.

New Option in the Lives Saved Tool (LiST) Allows for the Conversion of Prevalence of Small-for-Gestational-Age and Preterm Births to Prevalence of Low Birth Weight.

Science.gov (United States)

Kozuki, Naoko; Katz, Joanne; Clermont, Adrienne; Walker, Neff

2017-11-01

Background: The Lives Saved Tool (LiST) is a software model that estimates the health impact of scaling up interventions on maternal and child health. One of the outputs of the model is an estimation of births by fetal size [appropriate-for-gestational-age (AGA) or small-for-gestational-age (SGA)] and by length of gestation (term or preterm), both of which influence birth weight. LiST uses prevalence estimates of births in these categories rather than of birth weight categories, because the causes and health consequences differ between SGA and preterm birth. The World Health Assembly nutrition plan, however, has set the prevalence of low birth weight (LBW) as a key indicator, with a specific goal of a 30% reduction in LBW prevalence by 2025. Objective: The objective of the study is to develop an algorithm that will allow LiST users to estimate changes in prevalence of LBW on the basis of changes in coverage of interventions and the resulting impact on prevalence estimates of SGA and preterm births. Methods: The study used 13 prospective cohort data sets from low- and middle-income countries (LMICs; 4 from sub-Saharan Africa, 5 from Asia, and 4 from Latin America), with reliable measures of gestational age and birth weight. By calculating the proportion of LBW births among SGA and preterm births in each data set and meta-analyzing those estimates, we calculated region-specific pooled rates of LBW among SGA and preterm births. Results: In Africa, 0.4% of term-AGA, 36.7% of term-SGA, 49.3% of preterm-AGA, and 100.0% of preterm-SGA births were LBW. In Asia, 1.0% of term-SGA, 47.0% of term-SGA, 36.7% of preterm-AGA, and 100.0% of preterm-SGA births were LBW. In Latin America, 0.4% of term-AGA, 34.4% of term-SGA, 32.3% of preterm-AGA, and 100.0% of preterm-SGA births were LBW. Conclusions: The simple conversion factor proposed here allows for the estimation of LBW within LiST for most LMICs. This will allow LiST users to approximate the impact of their health programs on

Phase-covariant quantum cloning of qudits

International Nuclear Information System (INIS)

Fan Heng; Imai, Hiroshi; Matsumoto, Keiji; Wang, Xiang-Bin

2003-01-01

We study the phase-covariant quantum cloning machine for qudits, i.e., the input states in a d-level quantum system have complex coefficients with arbitrary phase but constant module. A cloning unitary transformation is proposed. After optimizing the fidelity between input state and single qudit reduced density operator of output state, we obtain the optimal fidelity for 1 to 2 phase-covariant quantum cloning of qudits and the corresponding cloning transformation

Behavioral Risk Factors: Selected Metropolitan Area Risk Trends (SMART) MMSA Age-adjusted Prevalence Data (2011 to Present)

Data.gov (United States)

U.S. Department of Health & Human Services — 2011 to present. BRFSS SMART MMSA age-adjusted prevalence combined land line and cell phone data. The Selected Metropolitan Area Risk Trends (SMART) project uses the...

Covariant differential calculus on quantum spheres of odd dimension

International Nuclear Information System (INIS)

Welk, M.

1998-01-01

Covariant differential calculus on the quantum spheres S q 2N-1 is studied. Two classification results for covariant first order differential calculi are proved. As an important step towards a description of the noncommutative geometry of the quantum spheres, a framework of covariant differential calculus is established, including first and higher order calculi and a symmetry concept. (author)

Prevalence of People Showing over Threshold Depressive Symptom in 40 Years and Over Aged

Directory of Open Access Journals (Sweden)

Mustafa Tozun

2008-12-01

Full Text Available BACKGROUND: The aim of this study was to investigate prevalence of threshold over depressive symptoms and to determine depression related risk factors among 40 years and over aged population in Kaymaz municipality of Sivrihisar county of Eskisehir city. MATERIAL-METHOD: This cross-sectional study was done from May 1st to June 30th 2007. In the study sample, there were 269 (50.1% men, 268 (49.9 % women, and total 537 people. The mean age of the study sample was 59.94 ± 10.94 year, and the range was 40 - 87 years. The questionnaire about socio-demographic characteristics and some depression related risk factors was filled out by interview Beck Depression Scale was used in determination of depression. Chi-square test was used in statistical analyses. RESULTS: Prevalence of people showing over threshold depressive symptoms was found 15.1% (n=81 in the study sample. Prevalence of people showing over threshold depressive symptoms was found significantly higher among women, unemployed people, uninsured people, smokers, people with physical defect, people with chronic disease, people with living negative event that is effect to his/her life in the last month, and people with family history of depression (for each one p<0.05. CONCLUSION: In the end of this study, it was suggested that health education for preventive precautions of depression in adults, frequent periodic screening for early diagnosis and treatment of depression, and directed to specialist doctors of people with depression should be made. [TAF Prev Med Bull 2008; 7(6.000: 485-490

Covariant Spectator Theory of heavy–light and heavy mesons and the predictive power of covariant interaction kernels

Energy Technology Data Exchange (ETDEWEB)

Leitão, Sofia, E-mail: sofia.leitao@tecnico.ulisboa.pt [CFTP, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal); Stadler, Alfred, E-mail: stadler@uevora.pt [Departamento de Física, Universidade de Évora, 7000-671 Évora (Portugal); CFTP, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal); Peña, M.T., E-mail: teresa.pena@tecnico.ulisboa.pt [Departamento de Física, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal); CFTP, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal); Biernat, Elmar P., E-mail: elmar.biernat@tecnico.ulisboa.pt [CFTP, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal)

2017-01-10

The Covariant Spectator Theory (CST) is used to calculate the mass spectrum and vertex functions of heavy–light and heavy mesons in Minkowski space. The covariant kernel contains Lorentz scalar, pseudoscalar, and vector contributions. The numerical calculations are performed in momentum space, where special care is taken to treat the strong singularities present in the confining kernel. The observed meson spectrum is very well reproduced after fitting a small number of model parameters. Remarkably, a fit to a few pseudoscalar meson states only, which are insensitive to spin–orbit and tensor forces and do not allow to separate the spin–spin from the central interaction, leads to essentially the same model parameters as a more general fit. This demonstrates that the covariance of the chosen interaction kernel is responsible for the very accurate prediction of the spin-dependent quark–antiquark interactions.

Is the Rise in the Prevalence of Renal Replacement Therapy at Older Ages the Price for Living Longer?

Directory of Open Access Journals (Sweden)

Frederik Peters

2018-05-01

Full Text Available BackgroundRenal replacement therapy (RRT is one of the most expensive in renal medicine. Cross-sectional studies suggest that life expectancy increases in the general population are associated with a higher burden of RRT. This study tests this hypothesis in a prospective setting among people aged 75+ living in Western Europe.MethodsWe gathered sex-specific data for 11 Western European countries in 2005–2014. RRT prevalence on country level was extracted from the ERA-EDTA registry, while data on population size and life expectancy for the 75+ age group came from the Eurostat database. GDP per capita was extracted from the OECD database. To measure the association between RRT prevalence and life expectancy, we performed Poisson regression models separately for each country and for all countries combined. To adjust for confounding, GDP per capita as well as time and country-fixed effects were included.ResultsOur analysis revealed that living longer coincides with rising RRT prevalence at ages 75+ in Western Europe between 2005 and 2014. On average, a 1-year increase in life expectancy was associated with a roughly 20% increase in RRT prevalence [(95% CI 21–23% in men and 19–22% in women]. However, after adjustments for confounding were made, the association became insignificant among women and became weaker among men, falling to a level of 11% [(95% CI 6–17%].ConclusionLiving longer was not necessarily associated with a higher burden of RRT in Western European countries.

HIGH DIMENSIONAL COVARIANCE MATRIX ESTIMATION IN APPROXIMATE FACTOR MODELS.

Science.gov (United States)

Fan, Jianqing; Liao, Yuan; Mincheva, Martina

2011-01-01

The variance covariance matrix plays a central role in the inferential theories of high dimensional factor models in finance and economics. Popular regularization methods of directly exploiting sparsity are not directly applicable to many financial problems. Classical methods of estimating the covariance matrices are based on the strict factor models, assuming independent idiosyncratic components. This assumption, however, is restrictive in practical applications. By assuming sparse error covariance matrix, we allow the presence of the cross-sectional correlation even after taking out common factors, and it enables us to combine the merits of both methods. We estimate the sparse covariance using the adaptive thresholding technique as in Cai and Liu (2011), taking into account the fact that direct observations of the idiosyncratic components are unavailable. The impact of high dimensionality on the covariance matrix estimation based on the factor structure is then studied.

An experimental study of spider-related covariation bias in 8-to 13-year-old children

NARCIS (Netherlands)

Muris, Peter; de Jong, Peter J.; Meesters, Cor; Waterreus, Bregje; van Lubeck, Janet

2005-01-01

Covariation bias can be defined as phobic subjects' tendency to overestimate the association between phobic stimuli and aversive outcomes. The current study presents two experiments that examined this type of cognitive bias in children aged 8-13 years (N = 147 in Experiment 1, N = 240 in Experiment

A New Approach for Nuclear Data Covariance and Sensitivity Generation

International Nuclear Information System (INIS)

Leal, L.C.; Larson, N.M.; Derrien, H.; Kawano, T.; Chadwick, M.B.

2005-01-01

Covariance data are required to correctly assess uncertainties in design parameters in nuclear applications. The error estimation of calculated quantities relies on the nuclear data uncertainty information available in the basic nuclear data libraries, such as the U.S. Evaluated Nuclear Data File, ENDF/B. The uncertainty files in the ENDF/B library are obtained from the analysis of experimental data and are stored as variance and covariance data. The computer code SAMMY is used in the analysis of the experimental data in the resolved and unresolved resonance energy regions. The data fitting of cross sections is based on generalized least-squares formalism (Bayes' theory) together with the resonance formalism described by R-matrix theory. Two approaches are used in SAMMY for the generation of resonance-parameter covariance data. In the evaluation process SAMMY generates a set of resonance parameters that fit the data, and, in addition, it also provides the resonance-parameter covariances. For existing resonance-parameter evaluations where no resonance-parameter covariance data are available, the alternative is to use an approach called the 'retroactive' resonance-parameter covariance generation. In the high-energy region the methodology for generating covariance data consists of least-squares fitting and model parameter adjustment. The least-squares fitting method calculates covariances directly from experimental data. The parameter adjustment method employs a nuclear model calculation such as the optical model and the Hauser-Feshbach model, and estimates a covariance for the nuclear model parameters. In this paper we describe the application of the retroactive method and the parameter adjustment method to generate covariance data for the gadolinium isotopes

Who perpetrates violence against children? A systematic analysis of age-specific and sex-specific data.

Science.gov (United States)

Devries, Karen; Knight, Louise; Petzold, Max; Merrill, Katherine G; Maxwell, Lauren; Williams, Abigail; Cappa, Claudia; Chan, Ko Ling; Garcia-Moreno, Claudia; Hollis, NaTasha; Kress, Howard; Peterman, Amber; Walsh, Sophie D; Kishor, Sunita; Guedes, Alessandra; Bott, Sarah; Butron Riveros, Betzabe C; Watts, Charlotte; Abrahams, Naeemah

2018-01-01

The epidemiology of violence against children is likely to differ substantially by sex and age of the victim and the perpetrator. Thus far, investment in effective prevention strategies has been hindered by lack of clarity in the burden of childhood violence across these dimensions. We produced the first age-specific and sex-specific prevalence estimates by perpetrator type for physical, sexual and emotional violence against children globally. We used random effects meta-regression to estimate prevalence. Estimates were adjusted for relevant quality covariates, variation in definitions of violence and weighted by region-specific, age-specific and sex-specific population data to ensure estimates reflect country population structures. Secondary data from 600 population or school-based representative datasets and 43 publications obtained via systematic literature review, representing 13 830 estimates from 171 countries. Estimates for recent violence against children aged 0-19 were included. The most common perpetrators of physical and emotional violence for both boys and girls across a range of ages are household members, with prevalence often surpassing 50%, followed by student peers. Children reported experiencing more emotional than physical violence from both household members and students. The most common perpetrators of sexual violence against girls aged 15-19 years are intimate partners; however, few data on other perpetrators of sexual violence against children are systematically collected internationally. Few age-specific and sex-specific data are available on violence perpetration by schoolteachers; however, existing data indicate high prevalence of physical violence from teachers towards students. Data from other authority figures, strangers, siblings and other adults are limited, as are data on neglect of children. Without further investment in data generation on violence exposure from multiple perpetrators for boys and girls of all ages, progress