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Sample records for population-based lifetime modeling

  1. Occupational self-coding and automatic recording (OSCAR): a novel web-based tool to collect and code lifetime job histories in large population-based studies.

    PubMed

    De Matteis, Sara; Jarvis, Deborah; Young, Heather; Young, Alan; Allen, Naomi; Potts, James; Darnton, Andrew; Rushton, Lesley; Cullinan, Paul

    2017-03-01

    Objectives The standard approach to the assessment of occupational exposures is through the manual collection and coding of job histories. This method is time-consuming and costly and makes it potentially unfeasible to perform high quality analyses on occupational exposures in large population-based studies. Our aim was to develop a novel, efficient web-based tool to collect and code lifetime job histories in the UK Biobank, a population-based cohort of over 500 000 participants. Methods We developed OSCAR (occupations self-coding automatic recording) based on the hierarchical structure of the UK Standard Occupational Classification (SOC) 2000, which allows individuals to collect and automatically code their lifetime job histories via a simple decision-tree model. Participants were asked to find each of their jobs by selecting appropriate job categories until they identified their job title, which was linked to a hidden 4-digit SOC code. For each occupation a job title in free text was also collected to estimate Cohen's kappa (κ) inter-rater agreement between SOC codes assigned by OSCAR and an expert manual coder. Results OSCAR was administered to 324 653 UK Biobank participants with an existing email address between June and September 2015. Complete 4-digit SOC-coded lifetime job histories were collected for 108 784 participants (response rate: 34%). Agreement between the 4-digit SOC codes assigned by OSCAR and the manual coder for a random sample of 400 job titles was moderately good [κ=0.45, 95% confidence interval (95% CI) 0.42-0.49], and improved when broader job categories were considered (κ=0.64, 95% CI 0.61-0.69 at a 1-digit SOC-code level). Conclusions OSCAR is a novel, efficient, and reasonably reliable web-based tool for collecting and automatically coding lifetime job histories in large population-based studies. Further application in other research projects for external validation purposes is warranted.

  2. Models for Battery Reliability and Lifetime

    SciTech Connect

    Smith, K.; Wood, E.; Santhanagopalan, S.; Kim, G. H.; Neubauer, J.; Pesaran, A.

    2014-03-01

    Models describing battery degradation physics are needed to more accurately understand how battery usage and next-generation battery designs can be optimized for performance and lifetime. Such lifetime models may also reduce the cost of battery aging experiments and shorten the time required to validate battery lifetime. Models for chemical degradation and mechanical stress are reviewed. Experimental analysis of aging data from a commercial iron-phosphate lithium-ion (Li-ion) cell elucidates the relative importance of several mechanical stress-induced degradation mechanisms.

  3. Universal Screening for Emotional and Behavioral Problems: Fitting a Population-Based Model

    ERIC Educational Resources Information Center

    Schanding, G. Thomas, Jr.; Nowell, Kerri P.

    2013-01-01

    Schools have begun to adopt a population-based method to conceptualizing assessment and intervention of students; however, little empirical evidence has been gathered to support this shift in service delivery. The present study examined the fit of a population-based model in identifying students' behavioral and emotional functioning using a…

  4. Association of Overweight with the Prevalence of Lifetime Psychiatric Disorders and Suicidality: General Population-based Study in Korea.

    PubMed

    Kim, Byung Soo; Chang, Sung Man; Seong, Su Jeong; Park, Jee Eun; Park, Subin; Hong, Jin Pyo; Bae, Jae Nam; Cho, Seong Jin; Hahm, Bong Jin; Lee, Dong Woo; Park, Jong Ik; Lee, Jun Young; Jeon, Hong Jin; Cho, Maeng Je

    2016-11-01

    Many epidemiological studies suggest that overweight is associated with an elevated risk of psychiatric disorders and suicidal tendency. However, findings vary across studies, and some have contradictory results. We investigated the relationship of overweight with a range of psychiatric disorders and suicidality in the Korean general population. A multistage cluster sampling design was adopted. A total of 6,022 participants aged 18-74 years completed face-to-face interviews (response rate: 78.7%) including assessment of psychiatric disorders, suicidality, and height and weight. Overweight (defined as body mass index of ≥ 25) was associated with an increase in the lifetime prevalence of depressive disorders (adjusted odds ratio [AOR] 1.38; 95% confidence interval [CI], 1.07-1.77), suicidal ideation (AOR, 1.42; 95% CI, 1.20-1.68), and suicidal plans (AOR, 1.44; 95% CI, 1.02-2.03), controlling for sociodemographic variables. Subgroup analysis found that the association between overweight and depressive disorders exists only in women aged 18-44 years (AOR, 1.75; 95% CI, 1.07-2.89) while the association of overweight with suicidal ideation (AOR, 2.08; 95% CI, 1.53-2.82) and suicide plans (AOR, 2.59; 95% CI, 1.25-5.37) existed only in men aged 18-44 years. Overweight was associated with increased odds of nicotine use disorders in women aged 18-44 years (AOR, 2.35; 95% CI, 1.02-5.43), but the association was in the opposite direction in men aged 45-74 years (AOR, 0.64; 95% CI, 0.43-0.94). In conclusion, overweight is related to various psychiatric disorders and suicidality in Korea. Policy makers and clinicians should pay more attention to the mental health of overweight individuals.

  5. Association of Overweight with the Prevalence of Lifetime Psychiatric Disorders and Suicidality: General Population-based Study in Korea

    PubMed Central

    2016-01-01

    Many epidemiological studies suggest that overweight is associated with an elevated risk of psychiatric disorders and suicidal tendency. However, findings vary across studies, and some have contradictory results. We investigated the relationship of overweight with a range of psychiatric disorders and suicidality in the Korean general population. A multistage cluster sampling design was adopted. A total of 6,022 participants aged 18–74 years completed face-to-face interviews (response rate: 78.7%) including assessment of psychiatric disorders, suicidality, and height and weight. Overweight (defined as body mass index of ≥ 25) was associated with an increase in the lifetime prevalence of depressive disorders (adjusted odds ratio [AOR] 1.38; 95% confidence interval [CI], 1.07–1.77), suicidal ideation (AOR, 1.42; 95% CI, 1.20–1.68), and suicidal plans (AOR, 1.44; 95% CI, 1.02–2.03), controlling for sociodemographic variables. Subgroup analysis found that the association between overweight and depressive disorders exists only in women aged 18–44 years (AOR, 1.75; 95% CI, 1.07–2.89) while the association of overweight with suicidal ideation (AOR, 2.08; 95% CI, 1.53–2.82) and suicide plans (AOR, 2.59; 95% CI, 1.25–5.37) existed only in men aged 18–44 years. Overweight was associated with increased odds of nicotine use disorders in women aged 18–44 years (AOR, 2.35; 95% CI, 1.02–5.43), but the association was in the opposite direction in men aged 45–74 years (AOR, 0.64; 95% CI, 0.43–0.94). In conclusion, overweight is related to various psychiatric disorders and suicidality in Korea. Policy makers and clinicians should pay more attention to the mental health of overweight individuals. PMID:27709862

  6. The association between a lifetime history of a neck injury in a motor vehicle collision and future neck pain: a population-based cohort study.

    PubMed

    Nolet, Paul S; Côté, Pierre; Cassidy, J David; Carroll, Linda J

    2010-06-01

    The objective of this population-based cohort study was to investigate the association between a lifetime history of neck injury from a motor vehicle collision and the development of troublesome neck pain. The current evidence suggests that individuals with a history of neck injury in a traffic collision are more likely to experience future neck pain. However, these results may suffer from residual confounding. Therefore, there is a need to test this association in a large population-based cohort with adequate control of known confounders. We formed a cohort of 919 randomly sampled Saskatchewan adults with no or mild neck pain in September 1995. At baseline, participants were asked if they ever injured their neck in a motor vehicle collision. Six and twelve months later, we asked about the presence of troublesome neck pain (grade II-IV) on the chronic pain grade questionnaire. Multivariable Cox regression was used to estimate the association between a lifetime history of neck injury in a motor vehicle collision and the onset of troublesome neck pain while controlling for known confounders. The follow-up rate was 73.5% (676/919) at 6 months and 63.1% (580/919) at 1 year. We found a positive association between a history of neck injury in a motor vehicle collision and the onset of troublesome neck pain after controlling for bodily pain and body mass index (adjusted HRR = 2.14; 95% CI 1.12-4.10). Our analysis suggests that a history of neck injury in a motor vehicle collision is a risk factor for developing future troublesome neck pain. The consequences of a neck injury in a motor vehicle collision can have long lasting effects and predispose individuals to experience recurrent episodes of neck pain.

  7. Reduced memory and attention performance in a population-based sample of young adults with a moderate lifetime use of cannabis, ecstasy and alcohol.

    PubMed

    Indlekofer, F; Piechatzek, M; Daamen, M; Glasmacher, C; Lieb, R; Pfister, H; Tucha, O; Lange, K W; Wittchen, H U; Schütz, C G

    2009-07-01

    reaction time was found. The results are consistent with decrements of memory and attentional performance described in previous studies. These effects are relatively small; however, it must be kept in mind that this study focussed on assessing young adults with moderate drug use from a population-based study.

  8. Population based models of cortical drug response: insights from anaesthesia

    PubMed Central

    Bojak, Ingo; Liley, David T. J.

    2008-01-01

    A great explanatory gap lies between the molecular pharmacology of psychoactive agents and the neurophysiological changes they induce, as recorded by neuroimaging modalities. Causally relating the cellular actions of psychoactive compounds to their influence on population activity is experimentally challenging. Recent developments in the dynamical modelling of neural tissue have attempted to span this explanatory gap between microscopic targets and their macroscopic neurophysiological effects via a range of biologically plausible dynamical models of cortical tissue. Such theoretical models allow exploration of neural dynamics, in particular their modification by drug action. The ability to theoretically bridge scales is due to a biologically plausible averaging of cortical tissue properties. In the resulting macroscopic neural field, individual neurons need not be explicitly represented (as in neural networks). The following paper aims to provide a non-technical introduction to the mean field population modelling of drug action and its recent successes in modelling anaesthesia. PMID:19003456

  9. Heuristic Modeling for TRMM Lifetime Predictions

    NASA Technical Reports Server (NTRS)

    Jordan, P. S.; Sharer, P. J.; DeFazio, R. L.

    1996-01-01

    Analysis time for computing the expected mission lifetimes of proposed frequently maneuvering, tightly altitude constrained, Earth orbiting spacecraft have been significantly reduced by means of a heuristic modeling method implemented in a commercial-off-the-shelf spreadsheet product (QuattroPro) running on a personal computer (PC). The method uses a look-up table to estimate the maneuver frequency per month as a function of the spacecraft ballistic coefficient and the solar flux index, then computes the associated fuel use by a simple engine model. Maneuver frequency data points are produced by means of a single 1-month run of traditional mission analysis software for each of the 12 to 25 data points required for the table. As the data point computations are required only a mission design start-up and on the occasion of significant mission redesigns, the dependence on time consuming traditional modeling methods is dramatically reduced. Results to date have agreed with traditional methods to within 1 to 1.5 percent. The spreadsheet approach is applicable to a wide variety of Earth orbiting spacecraft with tight altitude constraints. It will be particularly useful to such missions as the Tropical Rainfall Measurement Mission scheduled for launch in 1997, whose mission lifetime calculations are heavily dependent on frequently revised solar flux predictions.

  10. Estimating and modeling the cure fraction in population-based cancer survival analysis.

    PubMed

    Lambert, Paul C; Thompson, John R; Weston, Claire L; Dickman, Paul W

    2007-07-01

    In population-based cancer studies, cure is said to occur when the mortality (hazard) rate in the diseased group of individuals returns to the same level as that expected in the general population. The cure fraction (the proportion of patients cured of disease) is of interest to patients and is a useful measure to monitor trends in survival of curable disease. There are 2 main types of cure fraction model, the mixture cure fraction model and the non-mixture cure fraction model, with most previous work concentrating on the mixture cure fraction model. In this paper, we extend the parametric non-mixture cure fraction model to incorporate background mortality, thus providing estimates of the cure fraction in population-based cancer studies. We compare the estimates of relative survival and the cure fraction between the 2 types of model and also investigate the importance of modeling the ancillary parameters in the selected parametric distribution for both types of model.

  11. Probabilistic estimation of residential air exchange rates for population-based human exposure modeling

    EPA Science Inventory

    Residential air exchange rates (AERs) are a key determinant in the infiltration of ambient air pollution indoors. Population-based human exposure models using probabilistic approaches to estimate personal exposure to air pollutants have relied on input distributions from AER meas...

  12. Validation of population-based disease simulation models: a review of concepts and methods

    PubMed Central

    2010-01-01

    Background Computer simulation models are used increasingly to support public health research and policy, but questions about their quality persist. The purpose of this article is to review the principles and methods for validation of population-based disease simulation models. Methods We developed a comprehensive framework for validating population-based chronic disease simulation models and used this framework in a review of published model validation guidelines. Based on the review, we formulated a set of recommendations for gathering evidence of model credibility. Results Evidence of model credibility derives from examining: 1) the process of model development, 2) the performance of a model, and 3) the quality of decisions based on the model. Many important issues in model validation are insufficiently addressed by current guidelines. These issues include a detailed evaluation of different data sources, graphical representation of models, computer programming, model calibration, between-model comparisons, sensitivity analysis, and predictive validity. The role of external data in model validation depends on the purpose of the model (e.g., decision analysis versus prediction). More research is needed on the methods of comparing the quality of decisions based on different models. Conclusion As the role of simulation modeling in population health is increasing and models are becoming more complex, there is a need for further improvements in model validation methodology and common standards for evaluating model credibility. PMID:21087466

  13. Socioeconomic status during lifetime and cognitive impairment no-dementia in late life: the population-based aging in the Chianti Area (InCHIANTI) Study.

    PubMed

    Marengoni, Alessandra; Fratiglioni, Laura; Bandinelli, Stefania; Ferrucci, Luigi

    2011-01-01

    Thousand and twelve dementia-free elderly (60–98 years old) enrolled in the InChianti Study (Italy) were evaluated at baseline (1998–2000) and at 3-year follow-up (2001–2003) with the aim of analyzing the association of lifetime socioeconomic status (SES) with prevalent and incident cognitive impairment no-dementia (CIND). SES was defined from information on formal education, longest held occupation, and financial conditions through life. CIND was defined as age-adjusted Mini-Mental State Examination score one standard deviation below the baseline mean score of participants without dementia. Logistic regression and Cox proportional-hazards models were used to estimate the association of SES with CIND. Demographics,occupation characteristics (i.e., job stress and physical demand), cardiovascular diseases, diabetes, apolipoprotein E (APOE)genotype, smoking, alcohol consumption, depressive symptoms, and C-reactive protein were considered potential confounders.Prevalence of CIND was 17.7%. In the fully adjusted model, low education (OR = 2.1; 95% confidence intervals, CI = 1.4 to 3.2)was associated with prevalent CIND. Incidence rate of CIND was 66.0 per 1000 person-years. Low education (HR = 1.7; 95% CI = 1.04 to 2.6) and manual occupation (HR = 1.9; 95% CI = 1.0 to 3.6) were associated with incident CIND. Among covariates,high job-related physical demand was associated with both prevalent and incident CIND (OR = 1.6; 95% CI = 1.1 to 2.4 and HR= 1.5; 95% CI = 1.0 to 2.3). After stratification for education, manual occupation was still associated with CIND among participants with high education (HR = 2.2; 95% CI = 1.2 to 4.3 versus HR= 1.4; 95% CI = 0.2 to 10.4 among those with low education). Proxy markers of lifetime SES (low education, manual occupation and high physical demand) are cross-sectional correlates of CIND and predict incident CIND over a three-year follow-up.

  14. Models of population-based analyses for data collected from large extended families.

    PubMed

    Wang, Wenyu; Lee, Elisa T; Howard, Barbara V; Fabsitz, Richard R; Devereux, Richard B; MacCluer, Jean W; Laston, Sandra; Comuzzie, Anthony G; Shara, Nawar M; Welty, Thomas K

    2010-12-01

    Large studies of extended families usually collect valuable phenotypic data that may have scientific value for purposes other than testing genetic hypotheses if the families were not selected in a biased manner. These purposes include assessing population-based associations of diseases with risk factors/covariates and estimating population characteristics such as disease prevalence and incidence. Relatedness among participants however, violates the traditional assumption of independent observations in these classic analyses. The commonly used adjustment method for relatedness in population-based analyses is to use marginal models, in which clusters (families) are assumed to be independent (unrelated) with a simple and identical covariance (family) structure such as those called independent, exchangeable and unstructured covariance structures. However, using these simple covariance structures may not be optimally appropriate for outcomes collected from large extended families, and may under- or over-estimate the variances of estimators and thus lead to uncertainty in inferences. Moreover, the assumption that families are unrelated with an identical family structure in a marginal model may not be satisfied for family studies with large extended families. The aim of this paper is to propose models incorporating marginal models approaches with a covariance structure for assessing population-based associations of diseases with their risk factors/covariates and estimating population characteristics for epidemiological studies while adjusting for the complicated relatedness among outcomes (continuous/categorical, normally/non-normally distributed) collected from large extended families. We also discuss theoretical issues of the proposed models and show that the proposed models and covariance structure are appropriate for and capable of achieving the aim.

  15. Genetic epidemiology of self-reported lifetime DSM-IV major depressive disorder in a population-based twin sample of female adolescents

    PubMed Central

    Glowinski, Anne L.; Madden, Pamela A.F.; Bucholz, Kathleen K.; Lynskey, Michael T.; Heath, Andrew C.

    2005-01-01

    Background: In adults, about 40% of the variance in risk of Major Depressive Disorder (MDD) is due to genetic factors, but little data exist on the heritability of youth MDD. The goal of this study was the genetic analysis of MDD in an epidemiologically and genetically representative sample of adolescent female twins. Methods: A sample of 3416 female adolescent twins systematically ascertained from birth records was assessed using a structured telephone interview that included a comprehensive DSM-IV-based section for the diagnostic assessment of MDD. Mean subject age at time of assessment was 15.5 and participation rate exceeded 85%. Genetic modeling was conducted taking into consideration the problem of censoring, i.e., that younger adolescents were not through their period of risk for adolescent onset of MDD. Results: Lifetime self-reported MDD prevalence ranged from 1% under age 12 to 17.4% at age 19 and older. The genetic variance in risk of MDD was 40.4% (95% confidence interval (CI): 23.9–55.1), with the remaining variance explained by non-shared environmental effects 59.6% (95%CI: 44.9–76.1). Shared environmental effects were not significant. A significant recall bias was observed with older respondents on average reporting later onsets for their first episode of MDD. Conclusions: The genetic and environmental contributions to risk of MDD in this representative sample of female adolescent twins are remarkably analogous to findings from adult samples. These results are congruent with a conceptualization of adolescent MDD and adult MDD as having very similar etiologic determinants. PMID:14531581

  16. Hybrid Stochastic Models for Remaining Lifetime Prognosis

    DTIC Science & Technology

    2004-08-01

    sufficient conditions for an optimal replacement decision rule with respect to total cost and some bounds associated with this rule. The probability...degradation paths. Using Figure 3.15 and Table 3.8, we feel confident that we can adequately estimate the parameters of the lifetime distribution and...distribution, defined as the variance divided by the mean squared. The range for c2 is broken into three intevals , 0 < c2 ≤ 0.5, 0.5 < c2 ≤ 1.0, and

  17. Empirical membrane lifetime model for heavy duty fuel cell systems

    NASA Astrophysics Data System (ADS)

    Macauley, Natalia; Watson, Mark; Lauritzen, Michael; Knights, Shanna; Wang, G. Gary; Kjeang, Erik

    2016-12-01

    Heavy duty fuel cells used in transportation system applications such as transit buses expose the fuel cell membranes to conditions that can lead to lifetime-limiting membrane failure via combined chemical and mechanical degradation. Highly durable membranes and reliable predictive models are therefore needed in order to achieve the ultimate heavy duty fuel cell lifetime target of 25,000 h. In the present work, an empirical membrane lifetime model was developed based on laboratory data from a suite of accelerated membrane durability tests. The model considers the effects of cell voltage, temperature, oxygen concentration, humidity cycling, humidity level, and platinum in the membrane using inverse power law and exponential relationships within the framework of a general log-linear Weibull life-stress statistical distribution. The obtained model is capable of extrapolating the membrane lifetime from accelerated test conditions to use level conditions during field operation. Based on typical conditions for the Whistler, British Columbia fuel cell transit bus fleet, the model predicts a stack lifetime of 17,500 h and a membrane leak initiation time of 9200 h. Validation performed with the aid of a field operated stack confirmed the initial goal of the model to predict membrane lifetime within 20% of the actual operating time.

  18. Scalable Entity-Based Modeling of Population-Based Systems, Final LDRD Report

    SciTech Connect

    Cleary, A J; Smith, S G; Vassilevska, T K; Jefferson, D R

    2005-01-27

    The goal of this project has been to develop tools, capabilities and expertise in the modeling of complex population-based systems via scalable entity-based modeling (EBM). Our initial focal application domain has been the dynamics of large populations exposed to disease-causing agents, a topic of interest to the Department of Homeland Security in the context of bioterrorism. In the academic community, discrete simulation technology based on individual entities has shown initial success, but the technology has not been scaled to the problem sizes or computational resources of LLNL. Our developmental emphasis has been on the extension of this technology to parallel computers and maturation of the technology from an academic to a lab setting.

  19. Comprehensive, Population-Based Sensitivity Analysis of a Two-Mass Vocal Fold Model

    PubMed Central

    Robertson, Daniel; Zañartu, Matías; Cook, Douglas

    2016-01-01

    Previous vocal fold modeling studies have generally focused on generating detailed data regarding a narrow subset of possible model configurations. These studies can be interpreted to be the investigation of a single subject under one or more vocal conditions. In this study, a broad population-based sensitivity analysis is employed to examine the behavior of a virtual population of subjects and to identify trends between virtual individuals as opposed to investigating a single subject or model instance. Four different sensitivity analysis techniques were used in accomplishing this task. Influential relationships between model input parameters and model outputs were identified, and an exploration of the model’s parameter space was conducted. Results indicate that the behavior of the selected two-mass model is largely dominated by complex interactions, and that few input-output pairs have a consistent effect on the model. Results from the analysis can be used to increase the efficiency of optimization routines of reduced-order models used to investigate voice abnormalities. Results also demonstrate the types of challenges and difficulties to be expected when applying sensitivity analyses to more complex vocal fold models. Such challenges are discussed and recommendations are made for future studies. PMID:26845452

  20. Predictive Models of Li-ion Battery Lifetime

    SciTech Connect

    Smith, Kandler; Wood, Eric; Santhanagopalan, Shriram; Kim, Gi-heon; Shi, Ying; Pesaran, Ahmad

    2015-06-15

    It remains an open question how best to predict real-world battery lifetime based on accelerated calendar and cycle aging data from the laboratory. Multiple degradation mechanisms due to (electro)chemical, thermal, and mechanical coupled phenomena influence Li-ion battery lifetime, each with different dependence on time, cycling and thermal environment. The standardization of life predictive models would benefit the industry by reducing test time and streamlining development of system controls.

  1. Toxicogenetics: population-based testing of drug and chemical safety in mouse models.

    PubMed

    Rusyn, Ivan; Gatti, Daniel M; Wiltshire, Timothy; Wilshire, Timothy; Kleeberger, Steven R; Threadgill, David W

    2010-08-01

    The rapid decline in the cost of dense genotyping is paving the way for new DNA sequence-based laboratory tests to move quickly into clinical practice, and to ultimately help realize the promise of 'personalized' therapies. These advances are based on the growing appreciation of genetics as an important dimension in science and the practice of investigative pharmacology and toxicology. On the clinical side, both the regulators and the pharmaceutical industry hope that the early identification of individuals prone to adverse drug effects will keep advantageous medicines on the market for the benefit of the vast majority of prospective patients. On the environmental health protection side, there is a clear need for better science to define the range and causes of susceptibility to adverse effects of chemicals in the population, so that the appropriate regulatory limits are established. In both cases, most of the research effort is focused on genome-wide association studies in humans where de novo genotyping of each subject is required. At the same time, the power of population-based preclinical safety testing in rodent models (e.g., mouse) remains to be fully exploited. Here, we highlight the approaches available to utilize the knowledge of DNA sequence and genetic diversity of the mouse as a species in mechanistic toxicology research. We posit that appropriate genetically defined mouse models may be combined with the limited data from human studies to not only discover the genetic determinants of susceptibility, but to also understand the molecular underpinnings of toxicity.

  2. Progress towards a PETN Lifetime Prediction Model

    SciTech Connect

    Burnham, A K; Overturf III, G E; Gee, R; Lewis, P; Qiu, R; Phillips, D; Weeks, B; Pitchimani, R; Maiti, A; Zepeda-Ruiz, L; Hrousis, C

    2006-09-11

    Dinegar (1) showed that decreases in PETN surface area causes EBW detonator function times to increase. Thermal aging causes PETN to agglomerate, shrink, and densify indicating a ''sintering'' process. It has long been a concern that the formation of a gap between the PETN and the bridgewire may lead to EBW detonator failure. These concerns have led us to develop a model to predict the rate of coarsening that occurs with age for thermally driven PETN powder (50% TMD). To understand PETN contributions to detonator aging we need three things: (1) Curves describing function time dependence on specific surface area, density, and gap. (2) A measurement of the critical gap distance for no fire as a function of density and surface area for various wire configurations. (3) A model describing how specific surface area, density and gap change with time and temperature. We've had good success modeling high temperature surface area reduction and function time increase using a phenomenological deceleratory kinetic model based on a distribution of parallel nth-order reactions having evenly spaced activation energies where weighing factors of the reactions follows a Gaussian distribution about the reaction with the mean activation energy (Figure 1). Unfortunately, the mean activation energy derived from this approach is high (typically {approx}75 kcal/mol) so that negligible sintering is predicted for temperatures below 40 C. To make more reliable predictions, we've established a three-part effort to understand PETN mobility. First, we've measured the rates of step movement and pit nucleation as a function of temperature from 30 to 50 C for single crystals. Second, we've measured the evaporation rate from single crystals and powders from 105 to 135 C to obtain an activation energy for evaporation. Third, we've pursued mechanistic kinetic modeling of surface mobility, evaporation, and ripening.

  3. Population based model of human embryonic stem cell (hESC) differentiation during endoderm induction.

    PubMed

    Task, Keith; Jaramillo, Maria; Banerjee, Ipsita

    2012-01-01

    The mechanisms by which human embryonic stem cells (hESC) differentiate to endodermal lineage have not been extensively studied. Mathematical models can aid in the identification of mechanistic information. In this work we use a population-based modeling approach to understand the mechanism of endoderm induction in hESC, performed experimentally with exposure to Activin A and Activin A supplemented with growth factors (basic fibroblast growth factor (FGF2) and bone morphogenetic protein 4 (BMP4)). The differentiating cell population is analyzed daily for cellular growth, cell death, and expression of the endoderm proteins Sox17 and CXCR4. The stochastic model starts with a population of undifferentiated cells, wherefrom it evolves in time by assigning each cell a propensity to proliferate, die and differentiate using certain user defined rules. Twelve alternate mechanisms which might describe the observed dynamics were simulated, and an ensemble parameter estimation was performed on each mechanism. A comparison of the quality of agreement of experimental data with simulations for several competing mechanisms led to the identification of one which adequately describes the observed dynamics under both induction conditions. The results indicate that hESC commitment to endoderm occurs through an intermediate mesendoderm germ layer which further differentiates into mesoderm and endoderm, and that during induction proliferation of the endoderm germ layer is promoted. Furthermore, our model suggests that CXCR4 is expressed in mesendoderm and endoderm, but is not expressed in mesoderm. Comparison between the two induction conditions indicates that supplementing FGF2 and BMP4 to Activin A enhances the kinetics of differentiation than Activin A alone. This mechanistic information can aid in the derivation of functional, mature cells from their progenitors. While applied to initial endoderm commitment of hESC, the model is general enough to be applicable either to a system of

  4. Quantitative high-throughput screening for chemical toxicity in a population-based in vitro model.

    PubMed

    Lock, Eric F; Abdo, Nour; Huang, Ruili; Xia, Menghang; Kosyk, Oksana; O'Shea, Shannon H; Zhou, Yi-Hui; Sedykh, Alexander; Tropsha, Alexander; Austin, Christopher P; Tice, Raymond R; Wright, Fred A; Rusyn, Ivan

    2012-04-01

    A shift in toxicity testing from in vivo to in vitro may efficiently prioritize compounds, reveal new mechanisms, and enable predictive modeling. Quantitative high-throughput screening (qHTS) is a major source of data for computational toxicology, and our goal in this study was to aid in the development of predictive in vitro models of chemical-induced toxicity, anchored on interindividual genetic variability. Eighty-one human lymphoblast cell lines from 27 Centre d'Etude du Polymorphisme Humain trios were exposed to 240 chemical substances (12 concentrations, 0.26nM-46.0μM) and evaluated for cytotoxicity and apoptosis. qHTS screening in the genetically defined population produced robust and reproducible results, which allowed for cross-compound, cross-assay, and cross-individual comparisons. Some compounds were cytotoxic to all cell types at similar concentrations, whereas others exhibited interindividual differences in cytotoxicity. Specifically, the qHTS in a population-based human in vitro model system has several unique aspects that are of utility for toxicity testing, chemical prioritization, and high-throughput risk assessment. First, standardized and high-quality concentration-response profiling, with reproducibility confirmed by comparison with previous experiments, enables prioritization of chemicals for variability in interindividual range in cytotoxicity. Second, genome-wide association analysis of cytotoxicity phenotypes allows exploration of the potential genetic determinants of interindividual variability in toxicity. Furthermore, highly significant associations identified through the analysis of population-level correlations between basal gene expression variability and chemical-induced toxicity suggest plausible mode of action hypotheses for follow-up analyses. We conclude that as the improved resolution of genetic profiling can now be matched with high-quality in vitro screening data, the evaluation of the toxicity pathways and the effects of

  5. Model selection and inference for censored lifetime medical expenditures.

    PubMed

    Johnson, Brent A; Long, Qi; Huang, Yijian; Chansky, Kari; Redman, Mary

    2016-09-01

    Identifying factors associated with increased medical cost is important for many micro- and macro-institutions, including the national economy and public health, insurers and the insured. However, assembling comprehensive national databases that include both the cost and individual-level predictors can prove challenging. Alternatively, one can use data from smaller studies with the understanding that conclusions drawn from such analyses may be limited to the participant population. At the same time, smaller clinical studies have limited follow-up and lifetime medical cost may not be fully observed for all study participants. In this context, we develop new model selection methods and inference procedures for secondary analyses of clinical trial data when lifetime medical cost is subject to induced censoring. Our model selection methods extend a theory of penalized estimating function to a calibration regression estimator tailored for this data type. Next, we develop a novel inference procedure for the unpenalized regression estimator using perturbation and resampling theory. Then, we extend this resampling plan to accommodate regularized coefficient estimation of censored lifetime medical cost and develop postselection inference procedures for the final model. Our methods are motivated by data from Southwest Oncology Group Protocol 9509, a clinical trial of patients with advanced nonsmall cell lung cancer, and our models of lifetime medical cost are specific to this population. But the methods presented in this article are built on rather general techniques and could be applied to larger databases as those data become available.

  6. Consistent two-lifetime model for spectral functions of superconductors

    NASA Astrophysics Data System (ADS)

    Herman, František; Hlubina, Richard

    2017-03-01

    Recently it has been found that models with at least two lifetimes have to be considered when analyzing the angle-resolved photoemission data in the nodal region of the cuprates [Kondo et al., Nat. Commun. 6, 7699 (2015), 10.1038/ncomms8699]. In this paper we compare two such models. First we show that the phenomenological model used by Kondo et al. violates the sum rule for the occupation number. Next we consider the recently proposed model of the so-called Dynes superconductors, wherein the two lifetimes measure the strengths of pair-conserving and pair-breaking processes. We demonstrate that the model of the Dynes superconductors is fully consistent with known exact results, and we study in detail the resulting spectral functions. Finally, we show that the spectral functions in the nodal region of the cuprates can be fitted well by the model of the Dynes superconductors.

  7. Remaining lifetime modeling using State-of-Health estimation

    NASA Astrophysics Data System (ADS)

    Beganovic, Nejra; Söffker, Dirk

    2017-08-01

    Technical systems and system's components undergo gradual degradation over time. Continuous degradation occurred in system is reflected in decreased system's reliability and unavoidably lead to a system failure. Therefore, continuous evaluation of State-of-Health (SoH) is inevitable to provide at least predefined lifetime of the system defined by manufacturer, or even better, to extend the lifetime given by manufacturer. However, precondition for lifetime extension is accurate estimation of SoH as well as the estimation and prediction of Remaining Useful Lifetime (RUL). For this purpose, lifetime models describing the relation between system/component degradation and consumed lifetime have to be established. In this contribution modeling and selection of suitable lifetime models from database based on current SoH conditions are discussed. Main contribution of this paper is the development of new modeling strategies capable to describe complex relations between measurable system variables, related system degradation, and RUL. Two approaches with accompanying advantages and disadvantages are introduced and compared. Both approaches are capable to model stochastic aging processes of a system by simultaneous adaption of RUL models to current SoH. The first approach requires a priori knowledge about aging processes in the system and accurate estimation of SoH. An estimation of SoH here is conditioned by tracking actual accumulated damage into the system, so that particular model parameters are defined according to a priori known assumptions about system's aging. Prediction accuracy in this case is highly dependent on accurate estimation of SoH but includes high number of degrees of freedom. The second approach in this contribution does not require a priori knowledge about system's aging as particular model parameters are defined in accordance to multi-objective optimization procedure. Prediction accuracy of this model does not highly depend on estimated SoH. This model

  8. Toxicogenetics: population-based testing of drug and chemical safety in mouse models

    PubMed Central

    Rusyn, Ivan; Gatti, Daniel M; Wiltshire, Timothy; Kleeberger, Steven R; Threadgill, David W

    2011-01-01

    The rapid decline in the cost of dense genotyping is paving the way for new DNA sequence-based laboratory tests to move quickly into clinical practice, and to ultimately help realize the promise of ‘personalized’ therapies. These advances are based on the growing appreciation of genetics as an important dimension in science and the practice of investigative pharmacology and toxicology. On the clinical side, both the regulators and the pharmaceutical industry hope that the early identification of individuals prone to adverse drug effects will keep advantageous medicines on the market for the benefit of the vast majority of prospective patients. On the environmental health protection side, there is a clear need for better science to define the range and causes of susceptibility to adverse effects of chemicals in the population, so that the appropriate regulatory limits are established. In both cases, most of the research effort is focused on genome-wide association studies in humans where de novo genotyping of each subject is required. At the same time, the power of population-based preclinical safety testing in rodent models (e.g., mouse) remains to be fully exploited. Here, we highlight the approaches available to utilize the knowledge of DNA sequence and genetic diversity of the mouse as a species in mechanistic toxicology research. We posit that appropriate genetically defined mouse models may be combined with the limited data from human studies to not only discover the genetic determinants of susceptibility, but to also understand the molecular underpinnings of toxicity. PMID:20704464

  9. Predictive Models of Li-ion Battery Lifetime (Presentation)

    SciTech Connect

    Smith, K.; Wood, E.; Santhanagopalan, S.; Kim, G.; Shi, Y.; Pesaran, A.

    2014-09-01

    Predictive models of Li-ion battery reliability must consider a multiplicity of electrochemical, thermal and mechanical degradation modes experienced by batteries in application environments. Complicating matters, Li-ion batteries can experience several path dependent degradation trajectories dependent on storage and cycling history of the application environment. Rates of degradation are controlled by factors such as temperature history, electrochemical operating window, and charge/discharge rate. Lacking accurate models and tests, lifetime uncertainty must be absorbed by overdesign and warranty costs. Degradation models are needed that predict lifetime more accurately and with less test data. Models should also provide engineering feedback for next generation battery designs. This presentation reviews both multi-dimensional physical models and simpler, lumped surrogate models of battery electrochemical and mechanical degradation. Models are compared with cell- and pack-level aging data from commercial Li-ion chemistries. The analysis elucidates the relative importance of electrochemical and mechanical stress-induced degradation mechanisms in real-world operating environments. Opportunities for extending the lifetime of commercial battery systems are explored.

  10. Dynamical modeling and lifetime analysis of geostationary transfer orbits

    NASA Astrophysics Data System (ADS)

    Wang, Yue; Gurfil, Pini

    2016-11-01

    The dynamics and lifetime reduction of geostationary transfer orbits (GTOs) are of great importance to space debris mitigation. The orbital dynamics, subjected to a complex interplay of multiple perturbations, are complicated and sensitive to the initial conditions and model parameters. In this paper, a simple but effective non-singular orbital dynamics model in terms of Milankovitch elements is derived. The orbital dynamics, which include the Earth oblateness, luni-solar perturbations, and atmospheric drag, are averaged over the orbital motion of the GTO object, or, as needed, also over the orbital motions of the Moon and Sun, to eliminate the short-period terms. After the averaging process, the effect of the atmospheric drag assumes a simple analytical form. The averaged orbital model is verified through a numerical simulation compared with commercial orbit propagators. GTO lifetime reduction by using the luni-solar perturbations is studied. It is shown that the long-period luni-solar perturbation is induced by the precession of the GTO orbital plane and apsidal line, whereas the short-period perturbation is induced by the periodic luni-solar orbital motions. The long- and short-period perturbations are isolated and studied separately, and their global distribution with respect to the orbital geometry is given. The desired initial orbital geometry with a short orbital lifetime is found and verified by a numerical simulation.

  11. Lifetime pharmacokinetic model for hydrophobic contaminants in marine mammals

    SciTech Connect

    Hickie, B.E.; Mackay, D.; Koning, J. de

    1999-11-01

    A physiologically based pharmacokinetic model is developed that describes the uptake and release of a hydrophobic organic chemical by a marine mammal over its entire lifetime, i.e., from birth to death. This model is applied to polychlorinated biphenyls (PCBs) in the beluga whale (Delphinapterus leucas). The processes treated are growth; uptake from food, milk, and air; disposition of the chemical among arterial and venous blood, liver, muscle, blubber, and rapidly perfused tissues; and losses by metabolism, release in exhaled air; and by egestion. A separate model is developed for females, which includes pregnancy, birth, and lactation. Food consumption is deduced from size, growth, and from activity-dependent bioenergetic data. The results obtained by simulating continuous PCB exposure over a 30-year period are in accordance with reported concentrations and show the importance of milk transfer to both mother and progeny and the tendency for continued accumulation over the animal's lifetime. Implications of the results are discussed, especially the need for improved data on diets, gut absorption characteristics, and various physiological parameters used in the model.

  12. LCP- LIFETIME COST AND PERFORMANCE MODEL FOR DISTRIBUTED PHOTOVOLTAIC SYSTEMS

    NASA Technical Reports Server (NTRS)

    Borden, C. S.

    1994-01-01

    The Lifetime Cost and Performance (LCP) Model was developed to assist in the assessment of Photovoltaic (PV) system design options. LCP is a simulation of the performance, cost, and revenue streams associated with distributed PV power systems. LCP provides the user with substantial flexibility in specifying the technical and economic environment of the PV application. User-specified input parameters are available to describe PV system characteristics, site climatic conditions, utility purchase and sellback rate structures, discount and escalation rates, construction timing, and lifetime of the system. Such details as PV array orientation and tilt angle, PV module and balance-of-system performance attributes, and the mode of utility interconnection are user-specified. LCP assumes that the distributed PV system is utility grid interactive without dedicated electrical storage. In combination with a suitable economic model, LCP can provide an estimate of the expected net present worth of a PV system to the owner, as compared to electricity purchased from a utility grid. Similarly, LCP might be used to perform sensitivity analyses to identify those PV system parameters having significant impact on net worth. The user describes the PV system configuration to LCP via the basic electrical components. The module is the smallest entity in the PV system which is modeled. A PV module is defined in the simulation by its short circuit current, which varies over the system lifetime due to degradation and failure. Modules are wired in series to form a branch circuit. Bypass diodes are allowed between modules in the branch circuits. Branch circuits are then connected in parallel to form a bus. A collection of buses is connected in parallel to form an increment to capacity of the system. By choosing the appropriate series-parallel wiring design, the user can specify the current, voltage, and reliability characteristics of the system. LCP simulation of system performance is site

  13. LIFETIME PREDICTION FOR MODEL 9975 O-RINGS IN KAMS

    SciTech Connect

    Hoffman, E.; Skidmore, E.

    2009-11-24

    The Savannah River Site (SRS) is currently storing plutonium materials in the K-Area Materials Storage (KAMS) facility. The materials are packaged per the DOE 3013 Standard and transported and stored in KAMS in Model 9975 shipping packages, which include double containment vessels sealed with dual O-rings made of Parker Seals compound V0835-75 (based on Viton{reg_sign} GLT). The outer O-ring of each containment vessel is credited for leaktight containment per ANSI N14.5. O-ring service life depends on many factors, including the failure criterion, environmental conditions, overall design, fabrication quality and assembly practices. A preliminary life prediction model has been developed for the V0835-75 O-rings in KAMS. The conservative model is based primarily on long-term compression stress relaxation (CSR) experiments and Arrhenius accelerated-aging methodology. For model development purposes, seal lifetime is defined as a 90% loss of measurable sealing force. Thus far, CSR experiments have only reached this target level of degradation at temperatures {ge} 300 F. At lower temperatures, relaxation values are more tolerable. Using time-temperature superposition principles, the conservative model predicts a service life of approximately 20-25 years at a constant seal temperature of 175 F. This represents a maximum payload package at a constant ambient temperature of 104 F, the highest recorded in KAMS to date. This is considered a highly conservative value as such ambient temperatures are only reached on occasion and for short durations. The presence of fiberboard in the package minimizes the impact of such temperature swings, with many hours to several days required for seal temperatures to respond proportionately. At 85 F ambient, a more realistic but still conservative value, bounding seal temperatures are reduced to {approx}158 F, with an estimated seal lifetime of {approx}35-45 years. The actual service life for O-rings in a maximum wattage package likely lies

  14. Sunspot and Starspot Lifetimes in a Turbulent Erosion Model

    NASA Astrophysics Data System (ADS)

    Litvinenko, Yuri E.; Wheatland, M. S.

    2017-01-01

    Quantitative models of sunspot and starspot decay predict the timescale of magnetic diffusion and may yield important constraints in stellar dynamo models. Motivated by recent measurements of starspot lifetimes, we investigate the disintegration of a magnetic flux tube by nonlinear diffusion. Previous theoretical studies are extended by considering two physically motivated functional forms for the nonlinear diffusion coefficient D: an inverse power-law dependence D ∝ B‑ν and a step-function dependence of D on the magnetic field magnitude B. Analytical self-similar solutions are presented for the power-law case, including solutions exhibiting “superfast” diffusion. For the step-function case, the heat-balance integral method yields approximate solutions, valid for moderately suppressed diffusion in the spot. The accuracy of the resulting solutions is confirmed numerically, using a method which provides an accurate description of long-time evolution by imposing boundary conditions at infinite distance from the spot. The new models may allow insight into the differences and similarities between sunspots and starspots.

  15. Simulation of Population-Based Commuter Exposure to NO2 Using Different Air Pollution Models

    PubMed Central

    Ragettli, Martina S.; Tsai, Ming-Yi; Braun-Fahrländer, Charlotte; de Nazelle, Audrey; Schindler, Christian; Ineichen, Alex; Ducret-Stich, Regina E.; Perez, Laura; Probst-Hensch, Nicole; Künzli, Nino; Phuleria, Harish C.

    2014-01-01

    We simulated commuter routes and long-term exposure to traffic-related air pollution during commute in a representative population sample in Basel (Switzerland), and evaluated three air pollution models with different spatial resolution for estimating commute exposures to nitrogen dioxide (NO2) as a marker of long-term exposure to traffic-related air pollution. Our approach includes spatially and temporally resolved data on actual commuter routes, travel modes and three air pollution models. Annual mean NO2 commuter exposures were similar between models. However, we found more within-city and within-subject variability in annual mean (±SD) NO2 commuter exposure with a high resolution dispersion model (40 ± 7 µg m−3, range: 21–61) than with a dispersion model with a lower resolution (39 ± 5 µg m−3; range: 24–51), and a land use regression model (41 ± 5 µg m−3; range: 24–54). Highest median cumulative exposures were calculated along motorized transport and bicycle routes, and the lowest for walking. For estimating commuter exposure within a city and being interested also in small-scale variability between roads, a model with a high resolution is recommended. For larger scale epidemiological health assessment studies, models with a coarser spatial resolution are likely sufficient, especially when study areas include suburban and rural areas. PMID:24823664

  16. Simulation of population-based commuter exposure to NO₂ using different air pollution models.

    PubMed

    Ragettli, Martina S; Tsai, Ming-Yi; Braun-Fahrländer, Charlotte; de Nazelle, Audrey; Schindler, Christian; Ineichen, Alex; Ducret-Stich, Regina E; Perez, Laura; Probst-Hensch, Nicole; Künzli, Nino; Phuleria, Harish C

    2014-05-12

    We simulated commuter routes and long-term exposure to traffic-related air pollution during commute in a representative population sample in Basel (Switzerland), and evaluated three air pollution models with different spatial resolution for estimating commute exposures to nitrogen dioxide (NO2) as a marker of long-term exposure to traffic-related air pollution. Our approach includes spatially and temporally resolved data on actual commuter routes, travel modes and three air pollution models. Annual mean NO2 commuter exposures were similar between models. However, we found more within-city and within-subject variability in annual mean (±SD) NO2 commuter exposure with a high resolution dispersion model (40 ± 7 µg m(-3), range: 21-61) than with a dispersion model with a lower resolution (39 ± 5 µg m(-3); range: 24-51), and a land use regression model (41 ± 5 µg m(-3); range: 24-54). Highest median cumulative exposures were calculated along motorized transport and bicycle routes, and the lowest for walking. For estimating commuter exposure within a city and being interested also in small-scale variability between roads, a model with a high resolution is recommended. For larger scale epidemiological health assessment studies, models with a coarser spatial resolution are likely sufficient, especially when study areas include suburban and rural areas.

  17. Evaluation of a spatially resolved forest fire smoke model for population-based epidemiologic exposure assessment.

    PubMed

    Yao, Jiayun; Eyamie, Jeff; Henderson, Sarah B

    2016-01-01

    Exposure to forest fire smoke (FFS) is associated with multiple adverse health effects, mostly respiratory. Findings for cardiovascular effects have been inconsistent, possibly related to the limitations of conventional methods to assess FFS exposure. In previous work, we developed an empirical model to estimate smoke-related fine particulate matter (PM2.5) for all populated areas in British Columbia (BC), Canada. Here, we evaluate the utility of our model by comparing epidemiologic associations between modeled and measured PM2.5. For each local health area (LHA), we used Poisson regression to estimate the effects of PM2.5 estimates and measurements on counts of medication dispensations and outpatient physician visits. We then used meta-regression to estimate the overall effects. A 10 μg/m(3) increase in modeled PM2.5 was associated with increased sabutamol dispensations (RR=1.04, 95% CI 1.03-1.06), and physician visits for asthma (1.06, 1.04-1.08), COPD (1.02, 1.00-1.03), lower respiratory infections (1.03, 1.00-1.05), and otitis media (1.05, 1.03-1.07), all comparable to measured PM2.5. Effects on cardiovascular outcomes were only significant using model estimates in all LHAs during extreme fire days. This suggests that the exposure model is a promising tool for increasing the power of epidemiologic studies to detect the health effects of FFS via improved spatial coverage and resolution.

  18. Identifying genetic loci associated with antidepressant drug response with drug-gene interaction models in a population-based study.

    PubMed

    Noordam, Raymond; Direk, Nese; Sitlani, Colleen M; Aarts, Nikkie; Tiemeier, Henning; Hofman, Albert; Uitterlinden, André G; Psaty, Bruce M; Stricker, Bruno H; Visser, Loes E

    2015-03-01

    It has been difficult to identify genes affecting drug response to Selective Serotonin Reuptake Inhibitors (SSRIs). We used multiple cross-sectional assessments of depressive symptoms in a population-based study to identify potential genetic interactions with SSRIs as a model to study genetic variants associated with SSRI response. This study, embedded in the prospective Rotterdam Study, included all successfully genotyped participants with data on depressive symptoms (CES-D scores). We used repeated measurement models to test multiplicative interaction between genetic variants and use of SSRIs on repeated CESD scores. Besides a genome-wide analysis, we also performed an analysis which was restricted to genes related to the serotonergic signaling pathway. A total of 273 out of 14,937 assessments of depressive symptoms in 6443 participants, use of an SSRI was recorded. After correction for multiple testing, no plausible loci were identified in the genome-wide analysis. However, among the top 10 independent loci with the lowest p-values, findings within two genes (FSHR and HMGB4) might be of interest. Among 26 genes related to the serotonergic signaling pathway, the rs6108160 polymorphism in the PLCB1 gene reached statistical significance after Bonferroni correction (p-value = 8.1e-5). Also, the widely replicated 102C > T polymorphism in the HTR2A gene showed a statistically significant drug-gene interaction with SSRI use. Therefore, the present study suggests that drug-gene interaction models on (repeated) cross-sectional assessments of depressive symptoms in a population-based study can identify potential loci that may influence SSRI response.

  19. Performance and Cost-Effectiveness of Computed Tomography Lung Cancer Screening Scenarios in a Population-Based Setting: A Microsimulation Modeling Analysis in Ontario, Canada

    PubMed Central

    ten Haaf, Kevin; Tammemägi, Martin C.; Bondy, Susan J.; van der Aalst, Carlijn M.; Gu, Sumei; de Koning, Harry J.

    2017-01-01

    Background The National Lung Screening Trial (NLST) results indicate that computed tomography (CT) lung cancer screening for current and former smokers with three annual screens can be cost-effective in a trial setting. However, the cost-effectiveness in a population-based setting with >3 screening rounds is uncertain. Therefore, the objective of this study was to estimate the cost-effectiveness of lung cancer screening in a population-based setting in Ontario, Canada, and evaluate the effects of screening eligibility criteria. Methods and Findings This study used microsimulation modeling informed by various data sources, including the Ontario Health Insurance Plan (OHIP), Ontario Cancer Registry, smoking behavior surveys, and the NLST. Persons, born between 1940 and 1969, were examined from a third-party health care payer perspective across a lifetime horizon. Starting in 2015, 576 CT screening scenarios were examined, varying by age to start and end screening, smoking eligibility criteria, and screening interval. Among the examined outcome measures were lung cancer deaths averted, life-years gained, percentage ever screened, costs (in 2015 Canadian dollars), and overdiagnosis. The results of the base-case analysis indicated that annual screening was more cost-effective than biennial screening. Scenarios with eligibility criteria that required as few as 20 pack-years were dominated by scenarios that required higher numbers of accumulated pack-years. In general, scenarios that applied stringent smoking eligibility criteria (i.e., requiring higher levels of accumulated smoking exposure) were more cost-effective than scenarios with less stringent smoking eligibility criteria, with modest differences in life-years gained. Annual screening between ages 55–75 for persons who smoked ≥40 pack-years and who currently smoke or quit ≤10 y ago yielded an incremental cost-effectiveness ratio of $41,136 Canadian dollars ($33,825 in May 1, 2015, United States dollars) per

  20. Mathematical model for adaptive evolution of populations based on a complex domain

    PubMed Central

    Ibrahim, Rabha W.; Ahmad, M.Z.; Al-Janaby, Hiba F.

    2015-01-01

    A mutation is ultimately essential for adaptive evolution in all populations. It arises all the time, but is mostly fixed by enzymes. Further, most do consider that the evolution mechanism is by a natural assortment of variations in organisms in line for random variations in their DNA, and the suggestions for this are overwhelming. The altering of the construction of a gene, causing a different form that may be communicated to succeeding generations, produced by the modification of single base units in DNA, or the deletion, insertion, or rearrangement of larger units of chromosomes or genes. This altering is called a mutation. In this paper, a mathematical model is introduced to this reality. The model describes the time and space for the evolution. The tool is based on a complex domain for the space. We show that the evolution is distributed with the hypergeometric function. The Boundedness of the evolution is imposed by utilizing the Koebe function. PMID:26858564

  1. Analysis of amyotrophic lateral sclerosis as a multistep process: a population-based modelling study

    PubMed Central

    Al-Chalabi, Ammar; Calvo, Andrea; Chio, Adriano; Colville, Shuna; Ellis, Cathy M; Hardiman, Orla; Heverin, Mark; Howard, Robin S; Huisman, Mark H B; Keren, Noa; Leigh, P Nigel; Mazzini, Letizia; Mora, Gabriele; Orrell, Richard W; Rooney, James; Scott, Kirsten M; Scotton, William J; Seelen, Meinie; Shaw, Christopher E; Sidle, Katie S; Swingler, Robert; Tsuda, Miho; Veldink, Jan H; Visser, Anne E; van den Berg, Leonard H; Pearce, Neil

    2014-01-01

    Summary Background Amyotrophic lateral sclerosis shares characteristics with some cancers, such as onset being more common in later life, progression usually being rapid, the disease affecting a particular cell type, and showing complex inheritance. We used a model originally applied to cancer epidemiology to investigate the hypothesis that amyotrophic lateral sclerosis is a multistep process. Methods We generated incidence data by age and sex from amyotrophic lateral sclerosis population registers in Ireland (registration dates 1995–2012), the Netherlands (2006–12), Italy (1995–2004), Scotland (1989–98), and England (2002–09), and calculated age and sex-adjusted incidences for each register. We regressed the log of age-specific incidence against the log of age with least squares regression. We did the analyses within each register, and also did a combined analysis, adjusting for register. Findings We identified 6274 cases of amyotrophic lateral sclerosis from a catchment population of about 34 million people. We noted a linear relationship between log incidence and log age in all five registers: England r2=0·95, Ireland r2=0·99, Italy r2=0·95, the Netherlands r2=0·99, and Scotland r2=0·97; overall r2=0·99. All five registers gave similar estimates of the linear slope ranging from 4·5 to 5·1, with overlapping confidence intervals. The combination of all five registers gave an overall slope of 4·8 (95% CI 4·5–5·0), with similar estimates for men (4·6, 4·3–4·9) and women (5·0, 4·5–5·5). Interpretation A linear relationship between the log incidence and log age of onset of amyotrophic lateral sclerosis is consistent with a multistage model of disease. The slope estimate suggests that amyotrophic lateral sclerosis is a six-step process. Identification of these steps could lead to preventive and therapeutic avenues. Funding UK Medical Research Council; UK Economic and Social Research Council; Ireland Health Research Board; The

  2. Radiation-induced aging of PDMS Elastomer TR-55: a summary of constitutive, mesoscale, and population-based models

    SciTech Connect

    Maiti, A; Weisgraber, T. H.; Dinh, L. N.

    2016-11-16

    Filled and cross-linked elastomeric rubbers are versatile network materials with a multitude of applications ranging from artificial organs and biomedical devices to cushions, coatings, adhesives, interconnects, and seismic-isolation-, thermal-, and electrical barriers External factors like mechanical stress, temperature fluctuations, or radiation are known to create chemical changes in such materials that can directly affect the molecular weight distribution (MWD) of the polymer between cross-links and alter the structural and mechanical properties. From a Materials Science point of view it is highly desirable to understand, effect, and manipulate such property changes in a controlled manner. In this report we summarize our modeling efforts on a polysiloxane elastomer TR-55, which is an important component in several of our systems, and representative of a wide class of filled rubber materials. The primary aging driver in this work has been γ-radiation, and a variety of modeling approaches have been employed, including constitutive, mesoscale, and population-based models. The work utilizes diverse experimental data, including mechanical stress-strain and compression set measurements, as well as MWD measurements using multiquantum NMR.

  3. Are Immigrants and Nationals Born to Immigrants at Higher Risk for Delayed or No Lifetime Breast and Cervical Cancer Screening? The Results from a Population-Based Survey in Paris Metropolitan Area in 2010

    PubMed Central

    Rondet, Claire; Lapostolle, Annabelle; Soler, Marion; Grillo, Francesca; Parizot, Isabelle; Chauvin, Pierre

    2014-01-01

    Objectives This study aims to compare breast cancer screening (BCS) and cervical cancer screening (CCS) practices of French women born to French parents with those of immigrants and nationals born to immigrants, taking their socioeconomic status into account. Methods The study is based on data collected in 2010 in the Paris metropolitan area among a representative sample of 3000 French-speaking adults. For women with no history of breast or cervical cancer, multivariate logistic regressions and structural equation models were used to investigate the factors associated with never having undergone BCS or CCS. Results We confirmed the existence of a strong gradient, with respect to migration origin, for delaying or never having undergone BCS or CCS. Thus, being a foreign immigrant or being French of immigrant parentage were risk factors for delayed and no lifetime screening. Interestingly, we found that this gradient persisted (at least partially) after adjusting for the women’s socioeconomic characteristics. Only the level of income seemed to play a mediating role, but only partially. We observed differences between BCS and CCS which suggest that organized CCS could be effective in reducing socioeconomic and/or ethnic inequities. Conclusion Socioeconomic status partially explained the screening nonparticipation on the part of French women of immigrant origin and foreign immigrants. This was more so the case with CCS than with BCS, which suggests that organized prevention programs might reduce social inequalities. PMID:24466323

  4. Advanced Models and Controls for Prediction and Extension of Battery Lifetime (Presentation)

    SciTech Connect

    Smith, K.; Wood, E.; Santhanagopalan, S.; Kim, G.; Pesaran, A.

    2014-02-01

    Predictive models of capacity and power fade must consider a multiplicity of degradation modes experienced by Li-ion batteries in the automotive environment. Lacking accurate models and tests, lifetime uncertainty must presently be absorbed by overdesign and excess warranty costs. To reduce these costs and extend life, degradation models are under development that predict lifetime more accurately and with less test data. The lifetime models provide engineering feedback for cell, pack and system designs and are being incorporated into real-time control strategies.

  5. Environment and the Lifetime of Tropical Deep Convection in a Cloud-Permitting Regional Model Simulation

    SciTech Connect

    Hagos, Samson M.; Feng, Zhe; McFarlane, Sally A.; Leung, Lai-Yung R.

    2013-08-01

    By applying a cloud tracking algorithm to tropical convective systems simulated by a regional high resolution model, the study documents environmental conditions before and after convective systems are initiated over ocean and land by following them during their lifetime. The comparative roles of various environmental fields in affecting the lifetime of convection are also quantified. The statistics of lifetime, maximum area, propagation speed and direction of the simulated deep convection agrees well with geostationary satellite observations. Over ocean, convective systems enhance surface fluxes through the associated wind gusts as well as cooling and drying of the boundary layer. A significant relationship is found between the mean surface fluxes during their lifetime and the longevity of the systems which in turn is related to the initial intensity of the moist updraft and to a lesser extent upper level shear. Over land, on the other hand, convective activity suppresses surface fluxes through cloud cover and the lifetime of convection is related to the upper level shear during their lifetime and strength of the heat fluxes several hours before the initiation of convection. For systems of equal lifetime, those over land are significantly more intense than those over ocean especially during early stages of their lifetime.

  6. Modeling Minority-Carrier Lifetime Techniques That Use Transient Excess-Carrier Decay: Preprint

    SciTech Connect

    Johnston, S. W.; Berman, G. M.; Ahrenkiel, R. K.

    2008-05-01

    Lifetime spectroscopy is a valuable tool for the characterization of PV materials. This paper combines modeling and experimental results to illustrate the injection-level dependent response of three transient excess-carrier decay techniques.

  7. Stratospheric lifetime ratio of CFC-11 and CFC-12 from satellite and model climatologies

    NASA Astrophysics Data System (ADS)

    Hoffmann, Lars; Hoppe, Charlotte; Müller, Rolf; Dutton, Geoffrey S.; Gille, John C.; Griessbach, Sabine; Jones, Ashley; Meyer, Catrin I.; Spang, Reinhold; Volk, C. Michael; Walker, Kaley A.

    2015-04-01

    Chlorofluorocarbons (CFCs) play a key role in stratospheric ozone loss and are strong infrared absorbers that contribute to global warming. The stratospheric lifetimes of CFCs are a measure of their stratospheric loss rates that are needed to determine global warming and ozone depletion potentials. We applied the tracer-tracer correlation approach to zonal mean climatologies from satellite measurements and model data to assess the lifetimes of CFCl3 (CFC-11) and CF2Cl2 (CFC-12). We present new estimates of the CFC-11/CFC-12 lifetime ratio and the absolute lifetime of CFC-12, based on a reference lifetime of 52 yr for CFC-11. We analyzed climatologies from three satellite missions, the Atmospheric Chemistry Experiment-Fourier Transform Spectrometer (ACE-FTS), the HIgh Resolution Dynamics Limb Sounder (HIRDLS), and the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS). We found a CFC-11/CFC-12 lifetime ratio of 0.47 ± 0.08 and a CFC-12 lifetime of 112(96 - 133) yr for ACE-FTS, a ratio of 0.46 ± 0.07 and a lifetime of 113(97 - 134) yr for HIRDLS, and a ratio of 0.46 ± 0.08 and a lifetime of 114(98 - 136) yr for MIPAS. The error-weighted, combined CFC-11/CFC-12 lifetime ratio is 0.46 ± 0.04 and the CFC-12 lifetime estimate is 113(103 - 124) yr. These results are in excellent agreement with the recent Stratosphere-troposphere Processes And their Role in Climate (SPARC) reassessment, which recommends lifetimes of 52(43 - 67) yr for CFC-11 and 102(88 - 122) yr for CFC-12, respectively. Having smaller uncertainties than the results from other recent studies, our estimates can help to better constrain CFC-11 and CFC-12 lifetime recommendations in future scientific studies and assessments. Furthermore, the satellite observations were used to validate first simulation results from a new coupled model system, which integrates a Lagrangian chemistry transport model into a climate model. For the coupled EMAC/CLaMS model we found a CFC-11/CFC-12 lifetime ratio

  8. Model evaluation of methods for estimating surface emissions and chemical lifetimes from satellite data

    NASA Astrophysics Data System (ADS)

    de Foy, Benjamin; Wilkins, Joseph L.; Lu, Zifeng; Streets, David G.; Duncan, Bryan N.

    2014-12-01

    Column densities from satellite retrievals can provide valuable information for estimating emissions and chemical lifetimes objectively across the globe. To better understand the uncertainties associated with these estimates, we test four methods using simulated column densities from a point source: a box model approach, a 2D Gaussian fit, an Inverse Radius fit and an Exponentially-Modified Gaussian fit. The model results were simulated using the WRF and CAMx models for the year 2005, for a single point source outside Atlanta in Georgia, USA with specified emissions and three chemical scenarios: no chemical reactions, 12 h chemical lifetime and 1 h chemical lifetime. No other sources were included in the simulations. We find that the box model provides reliable estimates irrespective of plume speed and plume direction, if the plume speed and the chemical lifetime are known accurately. The 2D Gaussian fit was found to be sensitive to plume speed and direction, and requires omnidirectional dispersion in order to have a decent fit. However, the 2D Gaussian fit is only an approximate fit to the data, and the discrepancies mean that the results are dependent on the geographical domain used for the optimization. An Inverse Radius fit is introduced to correct this issue, which is found to provide improved emissions and lifetime estimates. The Exponentially-Modified Gaussian fit also gave improved estimates. It is however dependent on accurate plume rotation such that reported chemical lifetimes with this method could be significantly underestimated.

  9. Temperature dependency of the silicon heterojunction lifetime model based on the amphoteric nature of dangling bonds

    NASA Astrophysics Data System (ADS)

    Vasudevan, R.; Poli, I.; Deligiannis, D.; Zeman, M.; Smets, A. H. M.

    2016-11-01

    This work adapts a model to simulate the carrier injection dependent minority carrier lifetime of crystalline silicon passivated with hydrogenated amorphous silicon at elevated temperatures. Two existing models that respectively calculate the bulk lifetime and surface recombination velocity are used and the full temperature dependency of these models are explored. After a thorough description of these temperature dependencies, experimental results using this model show that the minority carrier lifetime changes upon annealing of silicon heterojunction structures are not universal. Furthermore, comparisons of the temperature dependent model to using the room temperature model at elevated temperatures is given and significant differences are observed when using temperatures above 100 °C. This shows the necessity of taking temperature effects into account during in-situ annealing experiments.

  10. New Accelerated Testing and Lifetime Modeling Methods Promise Faster Development of More Durable MEAs

    SciTech Connect

    Pierpont, D. M.; Hicks, M. T.; Turner, P. L.; Watschke, T. M.

    2005-11-01

    For the successful commercialization of fuel cell technology, it is imperative that membrane electrode assembly (MEA) durability is understood and quantified. MEA lifetimes of 40,000 hours remain a key target for stationary power applications. Since it is impractical to wait 40,000 hours for durability results, it is critical to learn as much information as possible in as short a time period as possible to determine if an MEA sample will survive past its lifetime target. Consequently, 3M has utilized accelerated testing and statistical lifetime modeling tools to develop a methodology for evaluating MEA lifetime. Construction and implementation of a multi-cell test stand have allowed for multiple accelerated tests and stronger statistical data for learning about durability.

  11. Semiautomatic bladder segmentation on CBCT using a population-based model for multiple-plan ART of bladder cancer

    NASA Astrophysics Data System (ADS)

    Chai, Xiangfei; van Herk, Marcel; Betgen, Anja; Hulshof, Maarten; Bel, Arjan

    2012-12-01

    The aim of this study is to develop a novel semiautomatic bladder segmentation approach for selecting the appropriate plan from the library of plans for a multiple-plan adaptive radiotherapy (ART) procedure. A population-based statistical bladder model was first built from a training data set (95 bladder contours from 8 patients). This model was then used as constraint to segment the bladder in an independent validation data set (233 CBCT scans from the remaining 22 patients). All 3D bladder contours were converted into parametric surface representations using spherical harmonic expansion. Principal component analysis (PCA) was applied in the spherical harmonic-based shape parameter space to calculate the major variation of bladder shapes. The number of dominating PCA modes was chosen such that 95% of the total shape variation of the training data set was described. The automatic segmentation started from the bladder contour of the planning CT of each patient, which was modified by changing the weight of each PCA mode. As a result, the segmentation contour was deformed consistently with the training set to best fit the bladder boundary in the localization CBCT image. A cost function was defined to measure the goodness of fit of the segmentation on the localization CBCT image. The segmentation was obtained by minimizing this cost function using a simplex optimizer. After automatic segmentation, a fast manual correction method was provided to correct those bladders (parts) that were poorly segmented. Volume- and distance-based metrics and the accuracy of plan selection from multiple plans were evaluated to quantify the performance of the automatic and semiautomatic segmentation methods. For the training data set, only seven PCA modes were needed to represent 95% of the bladder shape variation. The mean CI overlap and residual error (SD) of automatic bladder segmentation over all of the validation data were 70.5% and 0.39 cm, respectively. The agreement of plan

  12. The storage lifetime model based on multi-performance degradation parameters

    NASA Astrophysics Data System (ADS)

    Haochun, Qi; Xiaoling, Zhang; Xuesong, Xie; Changzhi, Lü

    2014-10-01

    According to the multi-performance degradation of the bipolar transistor in the accelerating storage process, an extrapolation model of the storage lifetime is proposed. In this model, using the Wiener process simulates the mono-degradation process of each feature degradation; using the copula function describes the correlation among these feature degradations. The Wiener process and parameters in the copula function are considered to associate with the temperature, and their relationships can be represented by the converted equations. Through the maximum likelihood estimation, the parameters in the Wiener process can be found; introducing Kendall's tau, those in the copula function can be estimated. By conducting the regression analyses of the estimated values of the parameters in each stress, their corresponding converted equations can be shown. Based on the storage test data of bipolar transistors, with the estimation method, the storage lifetime is found. The findings show that the model is reasonable for the prediction of storage lifetime.

  13. Interpreting aerosol lifetimes using the GEOS-Chem model and constraints from radionuclide measurements

    NASA Astrophysics Data System (ADS)

    Croft, B.; Pierce, J. R.; Martin, R. V.

    2014-04-01

    Aerosol removal processes control global aerosol abundance, but the rate of that removal remains uncertain. A recent study of aerosol-bound radionuclide measurements after the Fukushima Daiichi nuclear power plant accident documents 137Cs removal (e-folding) times of 10.0-13.9 days, suggesting that mean aerosol lifetimes in the range of 3-7 days in global models might be too short by a factor of two. In this study, we attribute this discrepancy to differences between the e-folding and mean aerosol lifetimes. We implement a simulation of 137Cs and 133Xe into the GEOS-Chem chemical transport model and examine the removal rates for the Fukushima case. We find a general consistency between modelled and measured e-folding times. The simulated 137Cs global burden e-folding time is about 14 days. However, the simulated mean lifetime of aerosol-bound 137Cs over a 6-month post-accident period is only 1.8 days. We find that the mean lifetime depends strongly on the removal rates in the first few days after emissions, before the aerosols leave the boundary layer and are transported to altitudes and latitudes where lifetimes with respect to wet removal are longer by a few orders of magnitude. We present sensitivity simulations that demonstrate the influence of differences in altitude and location of the radionuclides on the mean lifetime. Global mean lifetimes are shown to strongly depend on the altitude of injection. The global mean 137Cs lifetime is more than one order of magnitude greater for the injection at 7 km than into the boundary layer above the Fukushima site. Instantaneous removal rates are slower during the first few days after the emissions for a free tropospheric versus boundary layer injection and this strongly controls the mean lifetimes. Global mean aerosol lifetimes for the GEOS-Chem model are 3-6 days, which is longer than that for the 137Cs injected at the Fukushima site (likely due to precipitation shortly after Fukushima emissions), but similar to the

  14. Lifetime prediction modeling of airfoils for advanced power generation

    NASA Astrophysics Data System (ADS)

    Karaivanov, Ventzislav Gueorguiev

    The use of gases produced from coal as a turbine fuel offers an attractive means for efficiently generating electric power from our Nation's most abundant fossil fuel resource. The oxy-fuel and hydrogen-fired turbine concepts promise increased efficiency and low emissions on the expense of increased turbine inlet temperature (TIT) and different working fluid. Developing the turbine technology and materials is critical to the creation of these near-zero emission power generation technologies. A computational methodology, based on three-dimensional finite element analysis (FEA) and damage mechanics is presented for predicting the evolution of creep and fatigue in airfoils. We took a first look at airfoil thermal distributions in these advanced turbine systems based on CFD analysis. The damage mechanics-based creep and fatigue models were implemented as user modified routine in commercial package ANSYS. This routine was used to visualize the creep and fatigue damage evolution over airfoils for hydrogen-fired and oxy-fuel turbines concepts, and regions most susceptible to failure were indentified. Model allows for interaction between creep and fatigue damage thus damage due to fatigue and creep processes acting separately in one cycle will affect both the fatigue and creep damage rates in the next cycle. Simulation results were presented for various thermal conductivity of the top coat. Surface maps were created on the airfoil showing the development of the TGO scale and the Al depletion of the bond coat. In conjunction with model development, laboratory-scale experimental validation was executed to evaluate the influence of operational compressive stress levels on the performance of the TBC system. TBC coated single crystal coupons were exposed isothermally in air at 900, 1000, 1100oC with and without compressive load. Exposed samples were cross-sectioned and evaluated with scanning electron microscope (SEM). Performance data was collected based on image analysis

  15. Phase of care prevalence for prostate cancer in New South Wales, Australia: A population-based modelling study

    PubMed Central

    Luo, Qingwei; Smith, David P.; Clements, Mark S.; Patel, Manish I.; O’Connell, Dianne L.

    2017-01-01

    Objective To develop a method for estimating the future numbers of prostate cancer survivors requiring different levels of care. Design, setting and participants Analysis of population-based cancer registry data for prostate cancer cases (aged 18–84 years) diagnosed in 1996–2007, and a linked dataset with hospital admission data for men with prostate cancer diagnosed during 2005–2007 in New South Wales (NSW), Australia. Methods Cancer registry data (1996–2007) were used to project complete prostate cancer prevalence in NSW, Australia for 2008–2017, and treatment information from hospital records (2005–2007) was used to estimate the inpatient care needs during the first year after diagnosis. The projected complete prevalence was divided into care needs-based groups. We first divided the cohort into two groups based on patient’s age (<75 and 75–84 years). The younger cohort was further divided into initial care and monitoring phases. Cause of death data were used as a proxy for patients requiring last year of life prostate cancer care. Finally, episode data were used to estimate the future number of cases with metastatic progression. Results Of the estimated total of 60,910 men with a previous diagnosis of prostate cancer in 2017, the largest groups will be older patients (52.0%) and younger men who require monitoring (42.5%). If current treatment patterns continue, in the first year post-diagnosis 41% (1380) of patients (<75 years) will have a radical prostatectomy, and 52.6% (1752) will be likely to have either active surveillance, external beam radiotherapy or androgen deprivation therapy. About 3% will require care for subsequent metastases, and 1288 men with prostate cancer are likely to die from the disease in 2017. Conclusions This method extends the application of routinely collected population-based data, and can contribute much to the knowledge of the number of men with prostate cancer and their health care requirements. This could be of

  16. Lifetime prediction for the subsurface crack propagation using three-dimensional dynamic FEA model

    NASA Astrophysics Data System (ADS)

    Yin, Yuan; Chen, Yun-Xia; Liu, Le

    2017-03-01

    The subsurface crack propagation is one of the major interests for gear system research. The subsurface crack propagation lifetime is the number of cycles remaining for a spall to appear, which can be obtained through either stress intensity factor or accumulated plastic strain analysis. In this paper, the heavy loads are applied to the gear system. When choosing stress intensity factor, the high compressive stress suppresses Mode I stress intensities and severely reduces Mode II stress intensities in the heavily loaded lubricated contacts. Such that, the accumulated plastic strain is selected to calculate the subsurface crack propagation lifetime from the three-dimensional FEA model through ANSYS Workbench transient analysis. The three-dimensional gear FEA dynamic model with the subsurface crack is built through dividing the gears into several small elements. The calculation of the total cycles of the elements is proposed based on the time-varying accumulated plastic strain, which then will be used to calculate the subsurface crack propagation lifetime. During this process, the demonstration from a subsurface crack to a spall can be uncovered. In addition, different sizes of the elements around the subsurface crack are compared in this paper. The influences of the frictional coefficient and external torque on the crack propagation lifetime are also discussed. The results show that the lifetime of crack propagation decreases significantly when the external load T increasing from 100 N m to 150 N m. Given from the distributions of the accumulated plastic strain, the lifetime shares no significant difference when the frictional coefficient f ranging in 0.04-0.06.

  17. Comparison of Accelerated Testing with Modeling to Predict Lifetime of CPV Solder Layers (Presentation)

    SciTech Connect

    Silverman, T. J.; Bosco, N.; Kurtz, S.

    2012-03-01

    Concentrating photovoltaic (CPV) cell assemblies can fail due to thermomechanical fatigue in the die-attach layer. In this presentation, we show the latest results from our computational model of thermomechanical fatigue. The model is used to estimate the relative lifetime of cell assemblies exposed to various temperature histories consistent with service and with accelerated testing. We also present early results from thermal cycling experiments designed to help validate the computational model.

  18. Application of genetically altered models as replacement for the lifetime mouse bioassay in pharmaceutical development.

    PubMed

    Alden, Carl; Smith, Peter; Morton, Dan

    2002-01-01

    The international pharmaceutical regulatory academic and industrial toxicology communities are collaborating to improve the efficiency and effectiveness of cancer hazard identification based on dramatic improvements in our understanding of the cancer process. Guidelines emanating from the International Conference on Harmonization provide for use of in vivo alternatives. Standard practices utilizing lifetime rat and mouse studies are recognized as seriously flawed with over 80% false positive rates. Furthermore, tobacco, the most important human carcinogen commercialized by industry, is negative in these traditional lifetime studies. The lifetime mouse bioassay is generally recognized in pharmaceutical development as not adding value in safety assessment. An international consortium under the aegis of ILSI has recently completed an evaluation of alternative mouse cancer models. Transgenic models are less expensive, use fewer animals and take less time than traditional lifetime bioassays. These alternative models have now been sufficiently evaluated to be considered useful in the safety assessment plan for pharmaceuticals in development. Specifically for example, the rasH2 appears useful in detecting nongenotoxic as well as genotoxic rodent tumorigens with improved concordance with human response. The p53+/- heterozygous mouse apparently identifies hormonal carcinogenic mechanisms, immunosuppressive carcinogens, and genotoxic carcinogens. The TG:AC predicts for rodent tumorigens applied topically. Recent experiences at FDA, CPMP, and MHW indicate that with good planning and agency interactions, regulatory acceptability can be anticipated.

  19. Lifetime growth in wild meerkats: incorporating life history and environmental factors into a standard growth model.

    PubMed

    English, Sinéad; Bateman, Andrew W; Clutton-Brock, Tim H

    2012-05-01

    Lifetime records of changes in individual size or mass in wild animals are scarce and, as such, few studies have attempted to model variation in these traits across the lifespan or to assess the factors that affect them. However, quantifying lifetime growth is essential for understanding trade-offs between growth and other life history parameters, such as reproductive performance or survival. Here, we used model selection based on information theory to measure changes in body mass over the lifespan of wild meerkats, and compared the relative fits of several standard growth models (monomolecular, von Bertalanffy, Gompertz, logistic and Richards). We found that meerkats exhibit monomolecular growth, with the best model incorporating separate growth rates before and after nutritional independence, as well as effects of season and total rainfall in the previous nine months. Our study demonstrates how simple growth curves may be improved by considering life history and environmental factors, which may be particularly relevant when quantifying growth patterns in wild populations.

  20. Quasars Are Not Light Bulbs: Testing Models of Quasar Lifetimes with the Observed Eddington Ratio Distribution

    NASA Astrophysics Data System (ADS)

    Hopkins, Philip F.; Hernquist, Lars

    2009-06-01

    We use the observed distribution of Eddington ratios as a function of supermassive black hole (BH) mass to constrain models of quasar/active galactic nucleus (AGN) lifetimes and light curves. Given the observed (well constrained) AGN luminosity function, a particular model for AGN light curves L(t) or, equivalently, the distribution of AGN lifetimes (time above a given luminosity t(>L)) translates directly and uniquely (without further assumptions) to a predicted distribution of Eddington ratios at each BH mass. Models for self-regulated BH growth, in which feedback produces a self-regulating "decay" or "blowout" phase after the AGN reaches some peak luminosity/BH mass and begins to expel gas and shut down accretion, make specific predictions for the light curves/lifetimes, distinct from, e.g., the expected distribution if AGN simply shut down by gas starvation (without feedback) and very different from the prediction of simple phenomenological "light bulb" scenarios. We show that the present observations of the Eddington ratio distribution, spanning nearly 5 orders of magnitude in Eddington ratio, 3 orders of magnitude in BH mass, and redshifts z = 0-1, agree well with the predictions of self-regulated models, and rule out phenomenological "light bulb" or pure exponential models, as well as gas starvation models, at high significance (~5σ). We also compare with observations of the distribution of Eddington ratios at a given AGN luminosity, and find similar good agreement (but show that these observations are much less constraining). We fit the functional form of the quasar lifetime distribution and provide these fits for use, and show how the Eddington ratio distributions place precise, tight limits on the AGN lifetimes at various luminosities, in agreement with model predictions. We compare with independent estimates of episodic lifetimes and use this to constrain the shape of the typical AGN light curve, and provide simple analytic fits to these for use in

  1. Regional differences in population-based cancer survival between six prefectures in Japan: application of relative survival models with funnel plots.

    PubMed

    Ito, Yuri; Ioka, Akiko; Tsukuma, Hideaki; Ajiki, Wakiko; Sugimoto, Tomoyuki; Rachet, Bernard; Coleman, Michel P

    2009-07-01

    We used new methods to examine differences in population-based cancer survival between six prefectures in Japan, after adjustment for age and stage at diagnosis. We applied regression models for relative survival to data from population-based cancer registries covering each prefecture for patients diagnosed with stomach, lung, or breast cancer during 1993-1996. Funnel plots were used to display the excess hazard ratio (EHR) for each prefecture, defined as the excess hazard of death from each cancer within 5 years of diagnosis relative to the mean excess hazard (in excess of national background mortality by age and sex) in all six prefectures combined. The contribution of age and stage to the EHR in each prefecture was assessed from differences in deviance-based R(2) between the various models. No significant differences were seen between prefectures in 5-year survival from breast cancer. For cancers of the stomach and lung, EHR in Osaka prefecture were above the upper 95% control limits. For stomach cancer, the age- and stage-adjusted EHR in Osaka were 1.29 for men and 1.43 for women, compared with Fukui and Yamagata. Differences in the stage at diagnosis of stomach cancer appeared to explain most of this excess hazard (61.3% for men, 56.8% for women), whereas differences in age at diagnosis explained very little (0.8%, 1.3%). This approach offers the potential to quantify the impact of differences in stage at diagnosis on time trends and regional differences in cancer survival. It underlines the utility of population-based cancer registries for improving cancer control.

  2. Parametric estimation of quality adjusted lifetime (QAL) distribution in progressive illness--death model.

    PubMed

    Pradhan, Biswabrata; Dewanji, Anup

    2009-07-10

    In this work, we consider the parametric estimation of quality adjusted lifetime (QAL) distribution in progressive illness-death models. The main idea of this paper is to derive the theoretical distribution of QAL for the progressive illness-death models, under parametric models for the sojourn time distributions in different states, and then replace the model parameters by their estimates obtained by standard techniques of survival analysis. The method of estimation of the model parameters is also described. A data set of IBCSG Trial V has been analyzed for illustration. Extension to more general illness-death models is also discussed.

  3. Resolving Nuclear Reactor Lifetime Extension Questions: A Combined Multiscale Modeling and Positron Characterization approach

    SciTech Connect

    Wirth, B; Asoka-Kumar, P; Denison, A; Glade, S; Howell, R; Marian, J; Odette, G; Sterne, P

    2004-04-06

    The objective of this work is to determine the chemical composition of nanometer precipitates responsible for irradiation hardening and embrittlement of reactor pressure vessel steels, which threaten to limit the operating lifetime of nuclear power plants worldwide. The scientific approach incorporates computational multiscale modeling of radiation damage and microstructural evolution in Fe-Cu-Ni-Mn alloys, and experimental characterization by positron annihilation spectroscopy and small angle neutron scattering. The modeling and experimental results are

  4. The application of cure models in the presence of competing risks: a tool for improved risk communication in population-based cancer patient survival.

    PubMed

    Eloranta, Sandra; Lambert, Paul C; Andersson, Therese M-L; Björkholm, Magnus; Dickman, Paul W

    2014-09-01

    Quantifying cancer patient survival from the perspective of cure is clinically relevant. However, most cure models estimate cure assuming no competing causes of death. We use a relative survival framework to demonstrate how flexible parametric cure models can be used in combination with competing-risks theory to incorporate noncancer deaths. Under a model that incorporates statistical cure, we present the probabilities that cancer patients (1) have died from their cancer, (2) have died from other causes, (3) will eventually die from their cancer, or (4) will eventually die from other causes, all as a function of time since diagnosis. We further demonstrate how conditional probabilities can be used to update the prognosis among survivors (eg, at 1 or 5 years after diagnosis) by summarizing the proportion of patients who will not die from their cancer. The proposed method is applied to Swedish population-based data for persons diagnosed with melanoma, colon cancer, or acute myeloid leukemia between 1973 and 2007.

  5. Assessing potential population impact of statin treatment for primary prevention of atherosclerotic cardiovascular diseases in the USA: population-based modelling study

    PubMed Central

    Yang, Quanhe; Zhong, Yuna; Gillespie, Cathleen; Merritt, Robert; Bowman, Barbara; George, Mary G; Flanders, W Dana

    2017-01-01

    Objective New cholesterol treatment guidelines from American College of Cardiology/American Heart Association recommend statin treatment for more of US population to prevent atherosclerotic cardiovascular disease (ASCVD). It is important to assess how new guidelines may affect population-level health. This study assessed the impact of statin use for primary prevention of ASCVD under the new guidelines. Methods We used data from 2010 US Multiple Cause Mortality, Third National Health and Nutrition Examination Survey (NHANES III) Linked Mortality File (1988–2006, n=8941) and NHANES 2005–2010 (n=3178) participants 40–75 years of age for the present study. Results Among 33.0 million adults meeting new guidelines for primary prevention of ASCVD, 8.8 million were taking statins; 24.2 million, including 7.7 million with diabetes, are eligible for statin treatment. If all those with diabetes used a statin, 2514 (95% CI 592 to 4142) predicted ASCVD deaths would be prevented annually with 482 (0 to 2239) predicted annual additional cases of myopathy based on randomised clinical trials (RCTs), and 11 801 (9251 to 14 916) using population-based study. Among 16.5 million without diabetes, 5425 (1276 to 8935) ASCVD deaths would be prevented annually with 16 406 (4922 to 26 250) predicted annual additional cases of diabetes and between 1030 (0 to 4791) and 24 302 (19 363 to 30 292) additional cases of myopathy based on RCTs and population-based study. Assuming 80% eligible population take statins with 80% medication adherence, among those without diabetes, the corresponding numbers were 3472 (817 to 5718) deaths, 10 500 (3150 to 16 800) diabetes, 660 (0 to 3066) myopathy (RCTs), and 15 554 (12 392 to 19 387) myopathy (population-based). The estimated total annual cost of statins use ranged from US$1.65 to US$6.5 billion if 100% of eligible population take statins. Conclusions This population-based modelling study focused on impact of statin use on

  6. Lifetime measurements in 71Ge and a new interacting boson-fermion model interpretation

    NASA Astrophysics Data System (ADS)

    Ivaşcu, M.; Mărginean, N.; Bucurescu, D.; Căta-Danil, I.; Ur, C. A.; Lobach, Yu. N.

    1999-08-01

    The lifetimes of twelve low spin excited states have been measured in 71Ge using the Doppler shift attenuation method in the 71Ga(p,nγ) reaction at 3.0 and 3.5 MeV incident energy. New interacting boson-fermion model calculations for this nucleus account well for the properties of all its levels known up to about 1.5 MeV excitation.

  7. Evaluation of Observed and Modelled Aerosol Lifetimes Using Radioactive Tracers of Opportunity and an Ensemble of 19 Global Models

    NASA Technical Reports Server (NTRS)

    Kristiansen, N. I.; Stohl, A.; Olivie, D. J. L.; Croft, B.; Sovde, O. A.; Klein, H.; Christoudias, T.; Kunkel, D.; Leadbetter, S. J.; Lee, Y. H.; Zhang, K.; Tsigaridis, K.; Bauer, S. E.; Faluvegi, G. S.; Shindell, D.

    2016-01-01

    Aerosols have important impacts on air quality and climate, but the processes affecting their removal from the atmosphere are not fully understood and are poorly constrained by observations. This makes modelled aerosol lifetimes uncertain. In this study, we make use of an observational constraint on aerosol lifetimes provided by radionuclide measurements and investigate the causes of differences within a set of global models. During the Fukushima Dai-Ichi nuclear power plant accident of March 2011, the radioactive isotopes cesium-137 (Cs-137) and xenon-133 (Xe-133) were released in large quantities. Cesium attached to particles in the ambient air, approximately according to their available aerosol surface area. Cs-137 size distribution measurements taken close to the power plant suggested that accumulation mode (AM) sulfate aerosols were the main carriers of cesium. Hence, Cs-137 can be used as a proxy tracer for the AM sulfate aerosol's fate in the atmosphere. In contrast, the noble gas Xe-133 behaves almost like a passive transport tracer. Global surface measurements of the two radioactive isotopes taken over several months after the release allow the derivation of a lifetime of the carrier aerosol. We compare this to the lifetimes simulated by 19 different atmospheric transport models initialized with identical emissions of Cs-137that were assigned to an aerosol tracer with each model's default properties of AM sulfate, and Xe-133 emissions that were assigned to a passive tracer. We investigate to what extent the modelled sulfate tracer can reproduce the measurements, especially with respect to the observed loss of aerosol mass with time. Modelled Cs-137and Xe-133 concentrations sampled at the same location and times as station measurements allow a direct comparison between measured and modelled aerosol lifetime. The e-folding lifetime e, calculated from station measurement data taken between 2 and 9 weeks after the start of the emissions, is 14.3 days (95

  8. Evaluation of observed and modelled aerosol lifetimes using radioactive tracers of opportunity and an ensemble of 19 global models

    DOE PAGES

    Kristiansen, N. I.; Stohl, A.; Olivie, D. J. L.; ...

    2016-03-17

    Aerosols have important impacts on air quality and climate, but the processes affecting their removal from the atmosphere are not fully understood and are poorly constrained by observations. This makes modelled aerosol lifetimes uncertain. In this study, we make use of an observational constraint on aerosol lifetimes provided by radionuclide measurements and investigate the causes of differences within a set of global models. During the Fukushima Dai-Ichi nuclear power plant accident of March 2011, the radioactive isotopes cesium-137 (137Cs) and xenon-133 (133Xe) were released in large quantities. Cesium attached to particles in the ambient air, approximately according to their available aerosolmore » surface area. 137Cs size distribution measurements taken close to the power plant suggested that accumulation-mode (AM) sulfate aerosols were the main carriers of cesium. Hence, 137Cs can be used as a proxy tracer for the AM sulfate aerosol's fate in the atmosphere. In contrast, the noble gas 133Xe behaves almost like a passive transport tracer. Global surface measurements of the two radioactive isotopes taken over several months after the release allow the derivation of a lifetime of the carrier aerosol. We compare this to the lifetimes simulated by 19 different atmospheric transport models initialized with identical emissions of 137Cs that were assigned to an aerosol tracer with each model's default properties of AM sulfate, and 133Xe emissions that were assigned to a passive tracer. We investigate to what extent the modelled sulfate tracer can reproduce the measurements, especially with respect to the observed loss of aerosol mass with time. Modelled 137Cs and 133Xe concentrations sampled at the same location and times as station measurements allow a direct comparison between measured and modelled aerosol lifetime. The e-folding lifetime τe, calculated from station measurement data taken between 2 and 9 weeks after the start of the emissions, is 14.3 days (95

  9. Evaluation of observed and modelled aerosol lifetimes using radioactive tracers of opportunity and an ensemble of 19 global models

    SciTech Connect

    Kristiansen, N. I.; Stohl, A.; Olivie, D. J. L.; Croft, B.; Sovde, O. A.; Klein, H.; Christoudias, T.; Kunkel, D.; Leadbetter, S. J.; Lee, Y. H.; Zhang, K.; Tsigaridis, K.; Bergman, T.; Evangeliou, N.; Wang, H.; Ma, P. -L.; Easter, R. C.; Rasch, P. J.; Liu, X.; Pitari, G.; Di Genova, G.; Zhao, S. Y.; Balkanski, Y.; Bauer, S. E.; Faluvegi, G. S.; Kokkola, H.; Martin, R. V.; Pierce, J. R.; Schulz, M.; Shindell, D.; Tost, H.; Zhang, H.

    2016-03-17

    Aerosols have important impacts on air quality and climate, but the processes affecting their removal from the atmosphere are not fully understood and are poorly constrained by observations. This makes modelled aerosol lifetimes uncertain. In this study, we make use of an observational constraint on aerosol lifetimes provided by radionuclide measurements and investigate the causes of differences within a set of global models. During the Fukushima Dai-Ichi nuclear power plant accident of March 2011, the radioactive isotopes cesium-137 (137Cs) and xenon-133 (133Xe) were released in large quantities. Cesium attached to particles in the ambient air, approximately according to their available aerosol surface area. 137Cs size distribution measurements taken close to the power plant suggested that accumulation-mode (AM) sulfate aerosols were the main carriers of cesium. Hence, 137Cs can be used as a proxy tracer for the AM sulfate aerosol's fate in the atmosphere. In contrast, the noble gas 133Xe behaves almost like a passive transport tracer. Global surface measurements of the two radioactive isotopes taken over several months after the release allow the derivation of a lifetime of the carrier aerosol. We compare this to the lifetimes simulated by 19 different atmospheric transport models initialized with identical emissions of 137Cs that were assigned to an aerosol tracer with each model's default properties of AM sulfate, and 133Xe emissions that were assigned to a passive tracer. We investigate to what extent the modelled sulfate tracer can reproduce the measurements, especially with respect to the observed loss of aerosol mass with time. Modelled 137Cs and 133Xe concentrations sampled at the same location and times as station measurements allow a direct comparison between measured and modelled aerosol lifetime. The e-folding lifetime

  10. Evaluation of observed and modelled aerosol lifetimes using radioactive tracers of opportunity and an ensemble of 19 global models

    NASA Astrophysics Data System (ADS)

    Kristiansen, N. I.; Stohl, A.; Olivié, D. J. L.; Croft, B.; Søvde, O. A.; Klein, H.; Christoudias, T.; Kunkel, D.; Leadbetter, S. J.; Lee, Y. H.; Zhang, K.; Tsigaridis, K.; Bergman, T.; Evangeliou, N.; Wang, H.; Ma, P.-L.; Easter, R. C.; Rasch, P. J.; Liu, X.; Pitari, G.; Di Genova, G.; Zhao, S. Y.; Balkanski, Y.; Bauer, S. E.; Faluvegi, G. S.; Kokkola, H.; Martin, R. V.; Pierce, J. R.; Schulz, M.; Shindell, D.; Tost, H.; Zhang, H.

    2016-03-01

    Aerosols have important impacts on air quality and climate, but the processes affecting their removal from the atmosphere are not fully understood and are poorly constrained by observations. This makes modelled aerosol lifetimes uncertain. In this study, we make use of an observational constraint on aerosol lifetimes provided by radionuclide measurements and investigate the causes of differences within a set of global models. During the Fukushima Dai-Ichi nuclear power plant accident of March 2011, the radioactive isotopes cesium-137 (137Cs) and xenon-133 (133Xe) were released in large quantities. Cesium attached to particles in the ambient air, approximately according to their available aerosol surface area. 137Cs size distribution measurements taken close to the power plant suggested that accumulation-mode (AM) sulfate aerosols were the main carriers of cesium. Hence, 137Cs can be used as a proxy tracer for the AM sulfate aerosol's fate in the atmosphere. In contrast, the noble gas 133Xe behaves almost like a passive transport tracer. Global surface measurements of the two radioactive isotopes taken over several months after the release allow the derivation of a lifetime of the carrier aerosol. We compare this to the lifetimes simulated by 19 different atmospheric transport models initialized with identical emissions of 137Cs that were assigned to an aerosol tracer with each model's default properties of AM sulfate, and 133Xe emissions that were assigned to a passive tracer. We investigate to what extent the modelled sulfate tracer can reproduce the measurements, especially with respect to the observed loss of aerosol mass with time. Modelled 137Cs and 133Xe concentrations sampled at the same location and times as station measurements allow a direct comparison between measured and modelled aerosol lifetime. The e-folding lifetime τe, calculated from station measurement data taken between 2 and 9 weeks after the start of the emissions, is 14.3 days (95

  11. Evaluation of observed and modelled aerosol lifetimes using radioactive tracers of opportunity and an ensemble of 19 global models

    NASA Astrophysics Data System (ADS)

    Kristiansen, N. I.; Stohl, A.; Olivié, D. J. L.; Croft, B.; Søvde, O. A.; Klein, H.; Christoudias, T.; Kunkel, D.; Leadbetter, S. J.; Lee, Y. H.; Zhang, K.; Tsigaridis, K.; Bergman, T.; Evangeliou, N.; Wang, H.; Ma, P.-L.; Easter, R. C.; Rasch, P. J.; Liu, X.; Pitari, G.; Di Genova, G.; Zhao, S. Y.; Balkanski, Y.; Bauer, S. E.; Faluvegi, G. S.; Kokkola, H.; Martin, R. V.; Pierce, J. R.; Schulz, M.; Shindell, D.; Tost, H.; Zhang, H.

    2015-09-01

    Aerosols have important impacts on air quality and climate, but the processes affecting their removal from the atmosphere are not fully understood and are poorly constrained by observations. This makes modelled aerosol lifetimes uncertain. In this study, we make use of an observational constraint on aerosol lifetimes provided by radionuclide measurements and investigate the causes of differences within a set of global models. During the Fukushima Dai-Ichi nuclear power plant accident of March 2011, the radioactive isotopes cesium-137 (137Cs) and xenon-133 (133Xe) were released in large quantities. Cesium attached to particles in the ambient air, approximately according to their available aerosol surface area. 137Cs size distribution measurements taken close to the power plant suggested that accumulation-mode (AM) sulphate aerosols were the main carriers for the cesium. Hence, 137Cs can be used as a proxy tracer for the AM sulphate aerosol's fate in the atmosphere. In contrast, the noble gas 133Xe behaves almost like a passive transport tracer. Global surface measurements of the two radioactive isotopes taken over several months after the release allow the derivation of a lifetime of the carrier aerosol. We compare this to the lifetimes simulated by 19 different atmospheric transport models initialized with identical emissions of 137Cs that were assigned to an aerosol tracer with each model's default properties of AM sulphate, and 133Xe emissions that were assigned to a passive tracer. We investigate to what extent the modelled sulphate tracer can reproduce the measurements, especially with respect to the observed loss of aerosol mass with time. Modelled 37Cs and 133Xe concentrations sampled at the same location and times as station measurements allow a direct comparison between measured and modelled aerosol lifetime. The e-folding lifetime τe, calculated from station measurement data taken between two and nine weeks after the start of the emissions, is 14.3 days

  12. A new lifetime estimation model for a quicker LED reliability prediction

    NASA Astrophysics Data System (ADS)

    Hamon, B. H.; Mendizabal, L.; Feuillet, G.; Gasse, A.; Bataillou, B.

    2014-09-01

    LED reliability and lifetime prediction is a key point for Solid State Lighting adoption. For this purpose, one hundred and fifty LEDs have been aged for a reliability analysis. LEDs have been grouped following nine current-temperature stress conditions. Stress driving current was fixed between 350mA and 1A and ambient temperature between 85C and 120°C. Using integrating sphere and I(V) measurements, a cross study of the evolution of electrical and optical characteristics has been done. Results show two main failure mechanisms regarding lumen maintenance. The first one is the typically observed lumen depreciation and the second one is a much more quicker depreciation related to an increase of the leakage and non radiative currents. Models of the typical lumen depreciation and leakage resistance depreciation have been made using electrical and optical measurements during the aging tests. The combination of those models allows a new method toward a quicker LED lifetime prediction. These two models have been used for lifetime predictions for LEDs.

  13. External validation of a COPD prediction model using population-based primary care data: a nested case-control study

    PubMed Central

    Nwaru, Bright I; Simpson, Colin R; Sheikh, Aziz; Kotz, Daniel

    2017-01-01

    Emerging models for predicting risk of chronic obstructive pulmonary disease (COPD) require external validation in order to assess their clinical value. We validated a previous model for predicting new onset COPD in a different database. We randomly drew 38,597 case-control pairs (total N = 77,194) of individuals aged ≥35 years and matched for sex, age, and general practice from the United Kingdom Clinical Practice Research Datalink database. We assessed accuracy of the model to discriminate between COPD cases and non-cases by calculating area under the receiver operator characteristic (ROCAUC) for the prediction scores. Analogous to the development model, ever smoking (OR 6.70; 95%CI 6.41–6.99), prior asthma (OR 6.43; 95%CI 5.85–7.07), and higher socioeconomic deprivation (OR 2.90; 95%CI 2.72–3.09 for highest vs. lowest quintile) increased the risk of COPD. The validated prediction scores ranged from 0–5.71 (ROCAUC 0.66; 95%CI 0.65–0.66) for males and 0–5.95 (ROCAUC 0.71; 95%CI 0.70–0.71) for females. We have confirmed that smoking, prior asthma, and socioeconomic deprivation are key risk factors for new onset COPD. Our model seems externally valid at identifying patients at risk of developing COPD. An impact assessment now needs to be undertaken to assess whether this prediction model can be applied in clinical care settings. PMID:28304375

  14. Lifetime of Cosmic-Ray Muons and the Standard Model of Fundamental Particles

    NASA Astrophysics Data System (ADS)

    Mukherji, Sahansha; Shevde, Yash; Majewski, Walerian

    2015-04-01

    Muon is one of the twelve fundamental particles of matter, having the longest free-particle lifetime. It decays into three other leptons through an exchange of the weak vector bosons W+/W-. Muons are present in the secondary cosmic ray showers in the atmosphere, reaching the sea level. By detecting time delay between arrival of the muon and an appearance of the decay electron in our single scintillation detector (donated by the Thomas Jefferson National Accelerator Facility, Newport News, VA), we measured muon's lifetime at rest. It compares well with the value predicted by the Standard Model of Particles. From the lifetime we were able to calculate the ratio gw /MW of the weak coupling constant gw (an analog of the electric charge) to the mass of the W-boson MW. Using further Standard Model relations and an experimental value for MW, we calculated the weak coupling constant, the electric charge of the muon, and the vacuum expectation value of the Higgs field. We determined the sea-level flux of cosmic muons.

  15. Neutrino sector and proton lifetime in a realistic SUSY S O (10 ) model

    NASA Astrophysics Data System (ADS)

    Severson, Matthew

    2015-11-01

    In this work I present a complete analysis of proton decay in an S O (10 ) model previously proposed by Dutta, Mimura, and Mohapatra. The 10 , 126 ¯ , and 120 Yukawa couplings contributing to fermion masses in this model have well-motivated restrictions on their textures intended to give favorable results for proton lifetime as well as a realistic fermion sector without the need for fine-tuning and for either type-I or type-II dominance in the neutrino mass matrix. I obtain a valid fit for the entire fermion sector for both types of seesaw dominance, including θ13 in good agreement with the most recent data. For the case with type-II seesaw, I find that using the Yukawa couplings fixed by the successful fermion sector fit, proton partial lifetime limits are satisfied for nearly every pertinent decay mode, even for nearly arbitrary values of the triplet Higgs mixing parameters, with only the K+ν ¯ mode requiring a minor O (1 0-1) cancellation in order to satisfy the experimental limit. I also find a maximum lifetime for that mode of τ (K+ν ¯ )˜1036 yr , which should be tested by forthcoming experiments. For the type-I seesaw case, I find that all six pertinent decay modes of interest are satisfied for values of the triplet mixing parameters giving no major enhancement, with modes other than K+ν ¯ easily satisfied for arbitrary mixing values, and with a maximum lifetime for K+ν ¯ of nearly 1038 yr .

  16. Diagnosis of Parkinson’s disease on the basis of clinical–genetic classification: a population-based modelling study

    PubMed Central

    Nalls, Mike A.; McLean, Cory Y.; Rick, Jacqueline; Eberly, Shirley; Hutten, Samantha J.; Gwinn, Katrina; Sutherland, Margaret; Martinez, Maria; Heutink, Peter; Williams, Nigel; Hardy, John; Gasser, Thomas; Brice, Alexis; Price, T. Ryan; Nicolas, Aude; Keller, Margaux F.; Molony, Cliona; Gibbs, J. Raphael; Chen-Plotkin, Alice; Suh, Eunran; Letson, Christopher; Fiandaca, Massimo S.; Mapstone, Mark; Federoff, Howard J.; Noyce, Alastair J; Morris, Huw; Van Deerlin, Vivianna M.; Weintraub, Daniel; Zabetian, Cyrus; Hernandez, Dena G.; Lesage, Suzanne; Mullins, Meghan; Conley, Emily Drabant; Northover, Carrie; Frasier, Mark; Marek, Ken; Day-Williams, Aaron G.; Stone, David J.; Ioannidis, John P. A.; Singleton, Andrew B.

    2015-01-01

    Background Accurate diagnosis and early detection of complex disease has the potential to be of enormous benefit to clinical trialists, patients, and researchers alike. We sought to create a non-invasive, low-cost, and accurate classification model for diagnosing Parkinson’s disease risk to serve as a basis for future disease prediction studies in prospective longitudinal cohorts. Methods We developed a simple disease classifying model within 367 patients with Parkinson’s disease and phenotypically typical imaging data and 165 controls without neurological disease of the Parkinson’s Progression Marker Initiative (PPMI) study. Olfactory function, genetic risk, family history of PD, age and gender were algorithmically selected as significant contributors to our classifying model. This model was developed using the PPMI study then tested in 825 patients with Parkinson’s disease and 261 controls from five independent studies with varying recruitment strategies and designs including the Parkinson’s Disease Biomarkers Program (PDBP), Parkinson’s Associated Risk Study (PARS), 23andMe, Longitudinal and Biomarker Study in PD (LABS-PD), and Morris K. Udall Parkinson’s Disease Research Center of Excellence (Penn-Udall). Findings Our initial model correctly distinguished patients with Parkinson’s disease from controls at an area under the curve (AUC) of 0.923 (95% CI = 0.900 – 0.946) with high sensitivity (0.834, 95% CI = 0.711 – 0.883) and specificity (0.903, 95% CI = 0.824 – 0.946) in PPMI at its optimal AUC threshold (0.655). The model is also well-calibrated with all Hosmer-Lemeshow simulations suggesting that when parsed into random subgroups, the actual data mirrors that of the larger expected data, demonstrating that our model is robust and fits well. Likewise external validation shows excellent classification of PD with AUCs of 0.894 in PDBP, 0.998 in PARS, 0.955 in 23andMe, 0.929 in LABS-PD, and 0.939 in Penn-Udall. Additionally, when our model

  17. Study of behavior and determination of customer lifetime value(CLV) using Markov chain model

    SciTech Connect

    Permana, Dony; Indratno, Sapto Wahyu; Pasaribu, Udjianna S.

    2014-03-24

    Customer Lifetime Value or CLV is a restriction on interactive marketing to help a company in arranging financial for the marketing of new customer acquisition and customer retention. Additionally CLV can be able to segment customers for financial arrangements. Stochastic models for the fairly new CLV used a Markov chain. In this model customer retention probability and new customer acquisition probability play an important role. This model is originally introduced by Pfeifer and Carraway in 2000 [1]. They introduced several CLV models, one of them only involves customer and former customer. In this paper we expand the model by adding the assumption of the transition from former customer to customer. In the proposed model, the CLV value is higher than the CLV value obtained by Pfeifer and Caraway model. But our model still requires a longer convergence time.

  18. Study of behavior and determination of customer lifetime value(CLV) using Markov chain model

    NASA Astrophysics Data System (ADS)

    Permana, Dony; Indratno, Sapto Wahyu; Pasaribu, Udjianna S.

    2014-03-01

    Customer Lifetime Value or CLV is a restriction on interactive marketing to help a company in arranging financial for the marketing of new customer acquisition and customer retention. Additionally CLV can be able to segment customers for financial arrangements. Stochastic models for the fairly new CLV used a Markov chain. In this model customer retention probability and new customer acquisition probability play an important role. This model is originally introduced by Pfeifer and Carraway in 2000 [1]. They introduced several CLV models, one of them only involves customer and former customer. In this paper we expand the model by adding the assumption of the transition from former customer to customer. In the proposed model, the CLV value is higher than the CLV value obtained by Pfeifer and Caraway model. But our model still requires a longer convergence time.

  19. Associations of iron metabolism genes with blood manganese levels: a population-based study with validation data from animal models

    PubMed Central

    2011-01-01

    Background Given mounting evidence for adverse effects from excess manganese exposure, it is critical to understand host factors, such as genetics, that affect manganese metabolism. Methods Archived blood samples, collected from 332 Mexican women at delivery, were analyzed for manganese. We evaluated associations of manganese with functional variants in three candidate iron metabolism genes: HFE [hemochromatosis], TF [transferrin], and ALAD [δ-aminolevulinic acid dehydratase]. We used a knockout mouse model to parallel our significant results as a novel method of validating the observed associations between genotype and blood manganese in our epidemiologic data. Results Percentage of participants carrying at least one copy of HFE C282Y, HFE H63D, TF P570S, and ALAD K59N variant alleles was 2.4%, 17.7%, 20.1%, and 6.4%, respectively. Percentage carrying at least one copy of either C282Y or H63D allele in HFE gene was 19.6%. Geometric mean (geometric standard deviation) manganese concentrations were 17.0 (1.5) μg/l. Women with any HFE variant allele had 12% lower blood manganese concentrations than women with no variant alleles (β = -0.12 [95% CI = -0.23 to -0.01]). TF and ALAD variants were not significant predictors of blood manganese. In animal models, Hfe-/- mice displayed a significant reduction in blood manganese compared with Hfe+/+ mice, replicating the altered manganese metabolism found in our human research. Conclusions Our study suggests that genetic variants in iron metabolism genes may contribute to variability in manganese exposure by affecting manganese absorption, distribution, or excretion. Genetic background may be critical to consider in studies that rely on environmental manganese measurements. PMID:22074419

  20. Direct analysis of unphased SNP genotype data in population-based association studies via Bayesian partition modelling of haplotypes.

    PubMed

    Morris, Andrew P

    2005-09-01

    We describe a novel method for assessing the strength of disease association with single nucleotide polymorphisms (SNPs) in a candidate gene or small candidate region, and for estimating the corresponding haplotype relative risks of disease, using unphased genotype data directly. We begin by estimating the relative frequencies of haplotypes consistent with observed SNP genotypes. Under the Bayesian partition model, we specify cluster centres from this set of consistent SNP haplotypes. The remaining haplotypes are then assigned to the cluster with the "nearest" centre, where distance is defined in terms of SNP allele matches. Within a logistic regression modelling framework, each haplotype within a cluster is assigned the same disease risk, reducing the number of parameters required. Uncertainty in phase assignment is addressed by considering all possible haplotype configurations consistent with each unphased genotype, weighted in the logistic regression likelihood by their probabilities, calculated according to the estimated relative haplotype frequencies. We develop a Markov chain Monte Carlo algorithm to sample over the space of haplotype clusters and corresponding disease risks, allowing for covariates that might include environmental risk factors or polygenic effects. Application of the algorithm to SNP genotype data in an 890-kb region flanking the CYP2D6 gene illustrates that we can identify clusters of haplotypes with similar risk of poor drug metaboliser (PDM) phenotype, and can distinguish PDM cases carrying different high-risk variants. Further, the results of a detailed simulation study suggest that we can identify positive evidence of association for moderate relative disease risks with a sample of 1,000 cases and 1,000 controls.

  1. Atmospheric Muon Lifetime, Standard Model of Particles and the Lead Stopping Power for Muons

    NASA Astrophysics Data System (ADS)

    Gutarra-Leon, Angel; Barazandeh, Cioli; Majewski, Walerian

    2017-01-01

    The muon is a fundamental particles of matter. It decays into three other leptons through an exchange of the weak vector bosons W +/W-. Muons are present in the atmosphere from cosmic ray showers. By detecting the time delay between arrival of the muon and an appearance of the decay electron in our detector, we'll measure muon's lifetime at rest. From the lifetime we should be able to find the ratio gw /MW of the weak coupling constant gw (a weak analog of the electric charge) to the mass of the W-boson MW. Vacuum expectation value v of the Higg's field, which determines the masses of all particles of the Standard Model (SM), could be then calculated from our muon experiment as v =2MWc2/gw =(τ m μc2/6 π3ĥ)1/4m μc2 in terms of muon mass mµand muon lifetime τ only. Using known experimental value for MWc2 = 80.4 GeV we'll find the weak coupling constant gw. Using the SM relation e =gwsin θ√ hc ɛ0 with the experimental value of the Z0-photon weak mixing angle θ = 29o we could find from our muon lifetime the value of the elementary electric charge e. We'll determine the sea-level fluxes of low-energy and high-energy cosmic muons, then we'll shield the detector with varying thicknesses of lead plates and find the energy-dependent muon stopping power in lead.

  2. Approaches in methodology for population-based longitudinal study on neuroprotective model for healthy longevity (TUA) among Malaysian Older Adults.

    PubMed

    Shahar, Suzana; Omar, Azahadi; Vanoh, Divya; Hamid, Tengku Aizan; Mukari, Siti Zamratol Mai-Sarah; Din, Normah Che; Rajab, Nor Fadilah; Mohammed, Zainora; Ibrahim, Rahimah; Loo, Won Hui; Meramat, Asheila; Kamaruddin, Mohd Zul Amin; Bagat, Mohamad Fazdillah; Razali, Rosdinom

    2016-12-01

    A number of longitudinal studies on aging have been designed to determine the predictors of healthy longevity, including the neuroprotective factors, however, relatively few studies included a wide range of factors and highlighted the challenges faced during data collection. Thus, the longitudinal study on neuroprotective model for healthy longevity (LRGS TUA) has been designed to prospectively investigate the magnitude of cognitive decline and its risk factors through a comprehensive multidimensional assessment comprising of biophysical health, auditory and visual function, nutrition and dietary pattern and psychosocial aspects. At baseline, subjects were interviewed for their status on sociodemographic, health, neuropsychological test, psychosocial and dietary intake. Subjects were also measured for anthropometric and physical function and fitness. Biospecimens including blood, buccal swap, hair and toenail were collected, processed and stored. A subsample was assessed for sensory function, i.e., vision and auditory. During follow-up, at 18 and 36 months, most of the measurements, along with morbidity and mortality outcomes will be collected. The description of mild cognitive impairment, successful aging and usual aging process is presented here. A total 2322 respondents were recruited in the data analysis at baseline. Most of the respondents were categorized as experiencing usual aging (73 %), followed by successful aging (11 %) and mild cognitive impairment (16 %). The LRGS TUA study is the most comprehensive longitudinal study on aging in Malaysia, and will contribute to the understanding of the aging process and factors associated with healthy aging and mental well-being of a multiethnic population in Malaysia.

  3. Budget Impact Analysis of Switching to Digital Mammography in a Population-Based Breast Cancer Screening Program: A Discrete Event Simulation Model

    PubMed Central

    Comas, Mercè; Arrospide, Arantzazu; Mar, Javier; Sala, Maria; Vilaprinyó, Ester; Hernández, Cristina; Cots, Francesc; Martínez, Juan; Castells, Xavier

    2014-01-01

    Objective To assess the budgetary impact of switching from screen-film mammography to full-field digital mammography in a population-based breast cancer screening program. Methods A discrete-event simulation model was built to reproduce the breast cancer screening process (biennial mammographic screening of women aged 50 to 69 years) combined with the natural history of breast cancer. The simulation started with 100,000 women and, during a 20-year simulation horizon, new women were dynamically entered according to the aging of the Spanish population. Data on screening were obtained from Spanish breast cancer screening programs. Data on the natural history of breast cancer were based on US data adapted to our population. A budget impact analysis comparing digital with screen-film screening mammography was performed in a sample of 2,000 simulation runs. A sensitivity analysis was performed for crucial screening-related parameters. Distinct scenarios for recall and detection rates were compared. Results Statistically significant savings were found for overall costs, treatment costs and the costs of additional tests in the long term. The overall cost saving was 1,115,857€ (95%CI from 932,147 to 1,299,567) in the 10th year and 2,866,124€ (95%CI from 2,492,610 to 3,239,638) in the 20th year, representing 4.5% and 8.1% of the overall cost associated with screen-film mammography. The sensitivity analysis showed net savings in the long term. Conclusions Switching to digital mammography in a population-based breast cancer screening program saves long-term budget expense, in addition to providing technical advantages. Our results were consistent across distinct scenarios representing the different results obtained in European breast cancer screening programs. PMID:24832200

  4. Lifetime Measurements of ^170Hf and a test of the Confined Beta Soft Rotor Model

    NASA Astrophysics Data System (ADS)

    Smith, M. K.; Werner, V.; Heinz, A.; Terry, J. R.; Qian, J.; Winkler, R.; Casperson, R.; Williams, E.; Berant, Z.; L"Uttke, R.; Shoraka, B.; Henning, G.

    2009-10-01

    Significant deviations from rigid rotor model energy level predictions have been known to occur in rare earth nuclei. Recently, it was shown these deviations may be caused by centrifugal stretching effects within the nucleus [1]. New geometrical models have been proposed that account for centrifugal stretching, such as the confined beta soft model (CBS). We present the results from a high precision lifetime experiment performed with the New Yale Plunger Device at WNSL, Yale University. The ground state band of ^170Hf was measured through the J=12^+ level using the Recoil Distance Doppler Shift method. Excited states were populated in the ^124Sn(^50Ti,γ)^170Hf fusion evaporation reaction. Using the lifetimes, the B(E2) values and the quadrupole deformation parameter are determined. Centrifugal stretching is observed as an increased deviation in energy at higher spins in 170Hf. These results are compared to theoretical predictions from the CBS rotor model. Supported by grant DE-FG02-91ER40609.[4pt] [1] Costin et al, Phys.Rev. C 79, 024307 (2009)

  5. Bayesian framework for parametric bivariate accelerated lifetime modeling and its application to hospital acquired infections.

    PubMed

    Bilgili, D; Ryu, D; Ergönül, Ö; Ebrahimi, N

    2016-03-01

    Infectious diseases that can be spread directly or indirectly from one person to another are caused by pathogenic microorganisms such as bacteria, viruses, parasites, or fungi. Infectious diseases remain one of the greatest threats to human health and the analysis of infectious disease data is among the most important application of statistics. In this article, we develop Bayesian methodology using parametric bivariate accelerated lifetime model to study dependency between the colonization and infection times for Acinetobacter baumannii bacteria which is leading cause of infection among the hospital infection agents. We also study their associations with covariates such as age, gender, apache score, antibiotics use 3 months before admission and invasive mechanical ventilation use. To account for singularity, we use Singular Bivariate Extreme Value distribution to model residuals in Bivariate Accelerated lifetime model under the fully Bayesian framework. We analyze a censored data related to the colonization and infection collected in five major hospitals in Turkey using our methodology. The data analysis done in this article is for illustration of our proposed method and can be applied to any situation that our model can be used.

  6. Temperature dependence of o-Ps annihilation lifetime in non-uniform cylindrical pores in comparison with ETE model

    NASA Astrophysics Data System (ADS)

    Khaghani, Morteza; Mehmandoost-Khajeh-Dad, Ali Akbar

    2017-04-01

    Ortho-positronium (o-Ps) annihilation lifetime was calculated in non-uniform cylinder-shaped pores by solving Schrodinger equation using a well-known multi-physics program called COMSOL. The o-Ps annihilation lifetime variation in terms of temperature was calculated on the basis of ETE model via a numerical method. The COMSOL simulations indicate that as long as the pore is uniform cylinder-shaped, the results agree with those of two-dimensional ETE model, whereas deformations in the cylinder shape (indentation or protrusion) change the temperature behavior of ETE model and, thereby, higher values are predicted for o-Ps lifetime in the pore at lower temperatures. The geometry of the non-uniform cylinder-shaped pores, which is accompanied by empirical evidence, can be used for the analysis of empirical results obtained from positron lifetime spectroscopy in different temperatures.

  7. Bayesian Network Model with Application to Smart Power Semiconductor Lifetime Data.

    PubMed

    Plankensteiner, Kathrin; Bluder, Olivia; Pilz, Jürgen

    2015-09-01

    In this article, Bayesian networks are used to model semiconductor lifetime data obtained from a cyclic stress test system. The data of interest are a mixture of log-normal distributions, representing two dominant physical failure mechanisms. Moreover, the data can be censored due to limited test resources. For a better understanding of the complex lifetime behavior, interactions between test settings, geometric designs, material properties, and physical parameters of the semiconductor device are modeled by a Bayesian network. Statistical toolboxes in MATLAB® have been extended and applied to find the best structure of the Bayesian network and to perform parameter learning. Due to censored observations Markov chain Monte Carlo (MCMC) simulations are employed to determine the posterior distributions. For model selection the automatic relevance determination (ARD) algorithm and goodness-of-fit criteria such as marginal likelihoods, Bayes factors, posterior predictive density distributions, and sum of squared errors of prediction (SSEP) are applied and evaluated. The results indicate that the application of Bayesian networks to semiconductor reliability provides useful information about the interactions between the significant covariates and serves as a reliable alternative to currently applied methods.

  8. The perpetual student: modeling duration of undergraduate studies based on lifetime-type educational data.

    PubMed

    Kalamatianou, Aglaia G; McClean, Sally

    2003-12-01

    It is important to educational planners to estimate the likelihood and time-scale of graduation of students enrolled on a curriculum. The particular case we are concerned with, emerges when studies are not completed in the prescribed interval of time. Under these circumstances we use a framework of survival analysis applied to lifetime-type educational data to examine the distribution of duration of undergraduate studies for 10,313 students, enrolled in a Greek university during ten consecutive academic years. Non-parametric and parametric survival models have been developed for handling this distribution as well as a modified procedure for testing goodness-of-fit of the models. Data censoring was taken into account in the statistical analysis and the problems of thresholding of graduation and of perpetual students are also addressed. We found that the proposed parametric model adequately describes the empirical distribution provided by non-parametric estimation. We also found significant difference between duration of studies of men and women students. The proposed methodology could be useful to analyse data from any other type and level of education or general lifetime data with similar characteristics.

  9. Modeling of LaB6 hollow cathode performance and lifetime

    NASA Astrophysics Data System (ADS)

    Pedrini, Daniela; Albertoni, Riccardo; Paganucci, Fabrizio; Andrenucci, Mariano

    2015-01-01

    Thermionic hollow cathodes are currently used as sources of electrons in a variety of space applications, in particular as cathodes/neutralizers of electric thrusters (Hall effect and ion thrusters). Numerical tools are needed to guide the design of new devices before their manufacturing and testing, since multiple geometrical parameters influence the cathode performance. A reduced-order, numerical model was developed to assess the performance of orificed hollow cathodes, with a focus on the operational lifetime. The importance of the lifetime prediction is tied to its impact on the operational lifetime of the thruster to which the cathode is coupled. The cathode architecture consists of a refractory metal tube with an internal electron emitter made of lanthanum hexaboride (LaB6). The choice of LaB6 accounts for the reduced evaporation rate, the low sensitivity to poisoning and the absence of an activation procedure with respect to oxide cathodes. A LaB6 emitter is thus a valuable option for long-lasting cathodes, despite its relatively high work-function and reactivity with many refractory metals at high temperatures. The suggested reduced-order model self-consistently predicts the key parameters of the cathode operation, shedding light on the power deposition processes as well as on the main erosion mechanisms. Preliminary results showed good agreement with both the experimental data collected by Alta and data available from the literature for different operating conditions and power levels. Next developments will include further comparisons between theoretical and experimental data, considering cathodes of various size and operating conditions.

  10. BELA receiver performance modeling over the BepiColombo mission lifetime

    NASA Astrophysics Data System (ADS)

    Gunderson, Kurt; Thomas, Nicolas

    2010-01-01

    Performance modeling of the BepiColombo laser altimeter (BELA) receiver has been performed in the context of return pulse detection probability and measurement accuracies. Models have been extended beyond earlier work [Gunderson, K., Thomas, N., Rohner, M., 2006. A laser altimeter performance model and its application to BELA. IEEE Transactions on Geoscience and Remote Sensing 44, 3308-3319] to explore the receiver response to time-varying orbital conditions and potential instrument component degradations over the mission lifetime. New signal processing derivations are presented, and the set of measurement accuracy predictions has been broadened to include albedo and return pulse width in addition to range accuracy. Two detector gain optimization derivations are also described and applied as guides towards the identification of a preferred performance enhancing strategy.

  11. Improving Trust and Reputation Modeling in E-Commerce Using Agent Lifetime and Transaction Count

    NASA Astrophysics Data System (ADS)

    Cormier, Catherine; Tran, Thomas T.

    Effective and reliable trust and reputation modeling systems are central to the success of decentralized e-commerce systems where autonomous agents are relied upon to conduct commercial transactions. However, the subjective and social-based qualities that are inherent to trust and reputation introduce many complexities into the development of a reliable model. Existing research has successfully demonstrated how trust systems can be decentralized and has illustrated the importance of sharing trust information, or rather, modeling reputation. Still, few models have provided a solution for developing an initial set of advisors from whom to solicit reputation rankings, or have taken into account all of the social criteria used to determine trustworthiness. To meet these objectives, we propose the use of two new parameters in trust and reputation modeling: agent lifetime and total transaction count. We describe a model that employs these parameters to calculate an agent’s seniority, then apply this information when selecting agents for soliciting and ranking reputation information. Experiments using this model are described. The results are then presented and discussed to evaluate the effect of using these parameters in reputation modeling. We also discuss the value of our particular model in contrast with related work and conclude with directions for future research.

  12. Development of a lifetime prediction model for lithium-ion batteries based on extended accelerated aging test data

    NASA Astrophysics Data System (ADS)

    Ecker, Madeleine; Gerschler, Jochen B.; Vogel, Jan; Käbitz, Stefan; Hust, Friedrich; Dechent, Philipp; Sauer, Dirk Uwe

    2012-10-01

    Battery lifetime prognosis is a key requirement for successful market introduction of electric and hybrid vehicles. This work aims at the development of a lifetime prediction approach based on an aging model for lithium-ion batteries. A multivariable analysis of a detailed series of accelerated lifetime experiments representing typical operating conditions in hybrid electric vehicle is presented. The impact of temperature and state of charge on impedance rise and capacity loss is quantified. The investigations are based on a high-power NMC/graphite lithium-ion battery with good cycle lifetime. The resulting mathematical functions are physically motivated by the occurring aging effects and are used for the parameterization of a semi-empirical aging model. An impedance-based electric-thermal model is coupled to the aging model to simulate the dynamic interaction between aging of the battery and the thermal as well as electric behavior. Based on these models different drive cycles and management strategies can be analyzed with regard to their impact on lifetime. It is an important tool for vehicle designers and for the implementation of business models. A key contribution of the paper is the parameterization of the aging model by experimental data, while aging simulation in the literature usually lacks a robust empirical foundation.

  13. Modeling motivation and habit in driving behavior under lifetime driver's license revocation.

    PubMed

    Tseng, Chien-Ming; Chang, Hsin-Li; Woo, T Hugh

    2013-03-01

    The purpose of the present study was to verify the motivational factors underlying the theory of planned behavior (TPB) predicting the driving behavior of lifetime driving license revoked offenders. Of a total of 639 drivers whose licenses had been permanently revoked, 544 offenders completed a questionnaire constructed to measure attitudes toward behaviors, subjective norms, perceived behavioral control, behavioral intentions (the key constructs of the TPB), and previous driving habit strength. The finding of the study revealed that an offenders' driving behavior after a lifetime license revocation was significantly correlated to behavioral intention (R=0.60, p<0.01), perceived behavioral control (R=0.61, p<0.01), previous driving habit (R=0.44, p<0.01), and attitude (R=0.41, p<0.01). There was no evidence that subjective norms including road regulation, society ethics, and people important to offenders had an influence on driving behavior (R=0.03). Low driving habit strength offenders are motivated to drive because of behavioral intention, whereas strong driving habit strength offenders are motivated to drive because of perceived behavioral control. Previous driving habit strength is a moderator in the intention-behavior relationship. The model appeared successful when previous habits were weak, but less successful when previous habits were strong.

  14. The relationship between the Five-Factor Model personality traits and peptic ulcer disease in a large population-based adult sample.

    PubMed

    Realo, Anu; Teras, Andero; Kööts-Ausmees, Liisi; Esko, Tõnu; Metspalu, Andres; Allik, Jüri

    2015-12-01

    The current study examined the relationship between the Five-Factor Model personality traits and physician-confirmed peptic ulcer disease (PUD) diagnosis in a large population-based adult sample, controlling for the relevant behavioral and sociodemographic factors. Personality traits were assessed by participants themselves and by knowledgeable informants using the NEO Personality Inventory-3 (NEO PI-3). When controlling for age, sex, education, and cigarette smoking, only one of the five NEO PI-3 domain scales - higher Neuroticism - and two facet scales - lower A1: Trust and higher C1: Competence - made a small, yet significant contribution (p < 0.01) to predicting PUD in logistic regression analyses. In the light of these relatively modest associations, our findings imply that it is certain behavior (such as smoking) and sociodemographic variables (such as age, gender, and education) rather than personality traits that are associated with the diagnosis of PUD at a particular point in time. Further prospective studies with a longitudinal design and multiple assessments would be needed to fully understand if the FFM personality traits serve as risk factors for the development of PUD.

  15. Natural History of Dependency in the Elderly: A 24-Year Population-Based Study Using a Longitudinal Item Response Theory Model.

    PubMed

    Edjolo, Arlette; Proust-Lima, Cécile; Delva, Fleur; Dartigues, Jean-François; Pérès, Karine

    2016-02-15

    We aimed to describe the hierarchical structure of Instrumental Activities of Daily Living (IADL) and basic Activities of Daily Living (ADL) and trajectories of dependency before death in an elderly population using item response theory methodology. Data were obtained from a population-based French cohort study, the Personnes Agées QUID (PAQUID) Study, of persons aged ≥65 years at baseline in 1988 who were recruited from 75 randomly selected areas in Gironde and Dordogne. We evaluated IADL and ADL data collected at home every 2-3 years over a 24-year period (1988-2012) for 3,238 deceased participants (43.9% men). We used a longitudinal item response theory model to investigate the item sequence of 11 IADL and ADL combined into a single scale and functional trajectories adjusted for education, sex, and age at death. The findings confirmed the earliest losses in IADL (shopping, transporting, finances) at the partial limitation level, and then an overlapping of concomitant IADL and ADL, with bathing and dressing being the earliest ADL losses, and finally total losses for toileting, continence, eating, and transferring. Functional trajectories were sex-specific, with a benefit of high education that persisted until death in men but was only transient in women. An in-depth understanding of this sequence provides an early warning of functional decline for better adaptation of medical and social care in the elderly.

  16. Benefits and costs of methadone treatment: results from a lifetime simulation model.

    PubMed

    Zarkin, Gary A; Dunlap, Laura J; Hicks, Katherine A; Mamo, Daniel

    2005-11-01

    Several studies have examined the benefits and costs of drug treatment; however, they have typically focused on the benefits and costs of a single treatment episode. Although beneficial for certain analyses, the results are limited because they implicitly treat drug abuse as an acute problem that can be treated in one episode. We developed a Monte Carlo simulation model that incorporates the chronic nature of drug abuse. Our model represents the progression of individuals from the general population aged 18-60 with respect to their heroin use, treatment for heroin use, criminal behavior, employment, and health care use. We also present three model scenarios representing an increase in the probability of going to treatment, an increase in the treatment length of stay, and a scenario in which drug treatment is not available to evaluate how changes in treatment parameters affect model results. We find that the benefit-cost ratio of treatment from our lifetime model (37.72) exceeds the benefit-cost ratio from a static model (4.86). The model provides a rich characterization of the dynamics of heroin use and captures the notion of heroin use as a chronic recurring condition. Similar models can be developed for other chronic diseases, such as diabetes, mental illness, or cardiovascular disease.

  17. Development of a population-based threshold model of conidial germination for analysing the effects of physiological manipulation on the stress tolerance and infectivity of insect pathogenic fungi.

    PubMed

    Andersen, M; Magan, N; Mead, A; Chandler, D

    2006-09-01

    Entomopathogenic fungi are being used as biocontrol agents of insect pests, but their efficacy can be poor in environments where water availability is reduced. In this study, the potential to improve biocontrol by physiologically manipulating fungal inoculum was investigated. Cultures of Beauveria bassiana, Lecanicillium muscarium, Lecanicillium longisporum, Metarhizium anisopliae and Paecilomyces fumosoroseus were manipulated by growing them under conditions of water stress, which produced conidia with increased concentrations of erythritol. The time-course of germination of conidia at different water activities (water activity, aw) was described using a generalized linear model, and in most cases reducing the water activity of the germination medium delayed the onset of germination without affecting the distribution of germination times. The germination of M. anisopliae, L. muscarium, L. longisporum and P. fumosoroseus was accelerated over a range of aw levels as a result of physiological manipulation. However, the relationship between the effect of physiological manipulation on germination and the osmolyte content of conidia varied according to fungal species. There was a linear relationship between germination rate, expressed as the reciprocal of germination time, and aw of the germination medium, but there was no significant effect of fungal species or physiological manipulation on the aw threshold for germination. In bioassays with M. anisopliae, physiologically manipulated conidia germinated more rapidly on the surface of an insect host, the melon cotton aphid Aphis gossypii, and fungal virulence was increased even when relative humidity was reduced after an initial high period. It is concluded that physiological manipulation may lead to improvements in biocontrol in the field, but choice of fungal species/isolate will be critical. In addition, the population-based threshold model used in this study, which considered germination in terms of physiological

  18. Modeling of high homologous temperature deformation behavior for stress and life-time analyses

    SciTech Connect

    Krempl, E.

    1997-12-31

    Stress and lifetime analyses need realistic and accurate constitutive models for the inelastic deformation behavior of engineering alloys at low and high temperatures. Conventional creep and plasticity models have fundamental difficulties in reproducing high homologous temperature behavior. To improve the modeling capabilities {open_quotes}unified{close_quotes} state variable theories were conceived. They consider all inelastic deformation rate-dependent and do not have separate repositories for creep and plasticity. The viscoplasticity theory based on overstress (VBO), one of the unified theories, is introduced and its properties are delineated. At high homologous temperature where secondary and tertiary creep are observed modeling is primarily accomplished by a static recovery term and a softening isotropic stress. At low temperatures creep is merely a manifestation of rate dependence. The primary creep modeled at low homologous temperature is due to the rate dependence of the flow law. The model is unaltered in the transition from low to high temperature except that the softening of the isotropic stress and the influence of the static recovery term increase with an increase of the temperature.

  19. Solving inverse problem for Markov chain model of customer lifetime value using flower pollination algorithm

    NASA Astrophysics Data System (ADS)

    Al-Ma'shumah, Fathimah; Permana, Dony; Sidarto, Kuntjoro Adji

    2015-12-01

    Customer Lifetime Value is an important and useful concept in marketing. One of its benefits is to help a company for budgeting marketing expenditure for customer acquisition and customer retention. Many mathematical models have been introduced to calculate CLV considering the customer retention/migration classification scheme. A fairly new class of these models which will be described in this paper uses Markov Chain Models (MCM). This class of models has the major advantage for its flexibility to be modified to several different cases/classification schemes. In this model, the probabilities of customer retention and acquisition play an important role. From Pfeifer and Carraway, 2000, the final formula of CLV obtained from MCM usually contains nonlinear form of the transition probability matrix. This nonlinearity makes the inverse problem of CLV difficult to solve. This paper aims to solve this inverse problem, yielding the approximate transition probabilities for the customers, by applying metaheuristic optimization algorithm developed by Yang, 2013, Flower Pollination Algorithm. The major interpretation of obtaining the transition probabilities are to set goals for marketing teams in keeping the relative frequencies of customer acquisition and customer retention.

  20. The lifetime prediction model of stirling cryocooler for infrared detector assembly

    NASA Astrophysics Data System (ADS)

    Yang, Shao-hua; Liu, Xin-guang; Wu, Yi-nong

    2013-09-01

    With the rapid development of infrared focal plane array detector, stirling cyrocooler as a cold source has played an important role in space application. However, it is difficult to qualify its reliability and life expectancy before space application. Existing experiment and research data show that the most critical factor to restrict stirling cryocooler's service life is working gas contamination. Based on outgassing of stirling cryocooler internal material and its relationship with temperature, time and outgassing experimental data, the failure life model of contamination is proposed. By thousands of hours of accelerated life test, two types of prototype cryocooler have been verified for applicability of the proposed life model, and the working gas analysis of tested cryocoolers also proved the existence of contamination. Afterwards, through three group contaminations adding experiment of different level water vapor, the degradation characteristics of more than 1000 hour have proved complying with the life model above. Finally, the paper further verified the applicability of this model by the fitting of experimental data of long-term running in working condition. Consequently, the life model of stirling cryocooler caused contamination degradation is established, as well as an accelerated lifetime evaluation technique was proposed for stirling cryocooler.

  1. Evaluation of the FRAX model for hip fracture predictions in the population-based Kuopio Osteoporosis Risk Factor and Prevention Study (OSTPRE).

    PubMed

    Sund, Reijo; Honkanen, Risto; Johansson, Helena; Odén, Anders; McCloskey, Eugene; Kanis, John; Kröger, Heikki

    2014-07-01

    Calibration of the Finnish FRAX model was evaluated using a locally derived population-based cohort of postmenopausal women (n = 13,917). Hip fractures were observed from national register-based data and verified from radiological records. For a subpopulation of 11,182 women, there were enough data to calculate the fracture probabilities using the Finnish FRAX tool (without bone mineral density). A 10-year period prevalence of hip fractures to this subpopulation was 0.66 %. The expected numbers of hip fractures were significantly higher than the self reported ones (O/E ratio 0.46; 95 % CI 0.33-0.63), had a tendency to be greater than the observed ones (O/E ratio 0.83; 95 % CI 0.65-1.04), and calibration in terms of goodness-of-fit of absolute probabilities was questionable (P = 0.015). Strikingly, the 10-year period prevalence of hip fractures to the whole cohort was higher (0.84 %) than for the women with FRAX measurements (0.66 %). This was mainly the result of difference between people who had and who had not responded to postal enquiries (0.71 vs. 1.77 %, P < 0.0001). Self-reports missed to capture 38 % of all hip fractures in those who responded and about 45 % of hip fractures in women who had a FRAX estimate. The Finnish FRAX tool seems to provide appropriate discrimination for hip fracture risk, but caution is required in the interpretation of absolute risk, especially if used for population that may not be representing general population per se. Our study also showed that patients with no response had significantly higher hip fracture risk and that the use of purely self-reported hip fractures in calculations results in biased incidence and period prevalence estimates. Such important biases may remain unnoticed if there are no data from other sources available.

  2. Medication Adherence Patterns after Hospitalization for Coronary Heart Disease. A Population-Based Study Using Electronic Records and Group-Based Trajectory Models

    PubMed Central

    Librero, Julián; Sanfélix-Gimeno, Gabriel; Peiró, Salvador

    2016-01-01

    Objective To identify adherence patterns over time and their predictors for evidence-based medications used after hospitalization for coronary heart disease (CHD). Patients and Methods We built a population-based retrospective cohort of all patients discharged after hospitalization for CHD from public hospitals in the Valencia region (Spain) during 2008 (n = 7462). From this initial cohort, we created 4 subcohorts with at least one prescription (filled or not) from each therapeutic group (antiplatelet, beta-blockers, ACEI/ARB, statins) within the first 3 months after discharge. Monthly adherence was defined as having ≥24 days covered out of 30, leading to a repeated binary outcome measure. We assessed the membership to trajectory groups of adherence using group-based trajectory models. We also analyzed predictors of the different adherence patterns using multinomial logistic regression. Results We identified a maximum of 5 different adherence patterns: 1) Nearly-always adherent patients; 2) An early gap in adherence with a later recovery; 3) Brief gaps in medication use or occasional users; 4) A slow decline in adherence; and 5) A fast decline. These patterns represented variable proportions of patients, the descending trajectories being more frequent for the beta-blocker and ACEI/ARB cohorts (16% and 17%, respectively) than the antiplatelet and statin cohorts (10% and 8%, respectively). Predictors of poor or intermediate adherence patterns were having a main diagnosis of unstable angina or other forms of CHD vs. AMI in the index hospitalization, being born outside Spain, requiring copayment or being older. Conclusion Distinct adherence patterns over time and their predictors were identified. This may be a useful approach for targeting improvement interventions in patients with poor adherence patterns. PMID:27551748

  3. A mixture Weibull proportional hazard model for mechanical system failure prediction utilising lifetime and monitoring data

    NASA Astrophysics Data System (ADS)

    Zhang, Qing; Hua, Cheng; Xu, Guanghua

    2014-02-01

    As mechanical systems increase in complexity, it is becoming more and more common to observe multiple failure modes. The system failure can be regarded as the result of interaction and competition between different failure modes. It is therefore necessary to combine multiple failure modes when analysing the failure of an overall system. In this paper, a mixture Weibull proportional hazard model (MWPHM) is proposed to predict the failure of a mechanical system with multiple failure modes. The mixed model parameters are estimated by combining historical lifetime and monitoring data of all failure modes. In addition, the system failure probability density is obtained by proportionally mixing the failure probability density of multiple failure modes. Monitoring data are input into the MWPHM to estimate the system reliability and predict the system failure time. A simulated sample set is used to verify the ability of the MWPHM to model multiple failure modes. Finally, the MWPHM and the traditional Weibull proportional hazard model (WPHM) are applied to a high-pressure water descaling pump, which has two failure modes: sealing ring wear and thrust bearing damage. Results show that the MWPHM is greatly superior in system failure prediction to the WPHM.

  4. Cost-Effectiveness of Orthogeriatric and Fracture Liaison Service Models of Care for Hip Fracture Patients: A Population-Based Study.

    PubMed

    Leal, Jose; Gray, Alastair M; Hawley, Samuel; Prieto-Alhambra, Daniel; Delmestri, Antonella; Arden, Nigel K; Cooper, Cyrus; Javaid, M Kassim; Judge, Andrew

    2017-02-01

    Fracture liaison services are recommended as a model of best practice for organizing patient care and secondary fracture prevention for hip fracture patients, although variation exists in how such services are structured. There is considerable uncertainty as to which model is most cost-effective and should therefore be mandated. This study evaluated the cost- effectiveness of orthogeriatric (OG)- and nurse-led fracture liaison service (FLS) models of post-hip fracture care compared with usual care. Analyses were conducted from a health care and personal social services payer perspective, using a Markov model to estimate the lifetime impact of the models of care. The base-case population consisted of men and women aged 83 years with a hip fracture. The risk and costs of hip and non-hip fractures were derived from large primary and hospital care data sets in the UK. Utilities were informed by a meta-regression of 32 studies. In the base-case analysis, the orthogeriatric-led service was the most effective and cost-effective model of care at a threshold of £30,000 per quality-adjusted life years gained (QALY). For women aged 83 years, the OG-led service was the most cost-effective at £22,709/QALY. If only health care costs are considered, OG-led service was cost-effective at £12,860/QALY and £14,525/QALY for women and men aged 83 years, respectively. Irrespective of how patients were stratified in terms of their age, sex, and Charlson comorbidity score at index hip fracture, our results suggest that introducing an orthogeriatrician-led or a nurse-led FLS is cost-effective when compared with usual care. Although considerable uncertainty remains concerning which of the models of care should be preferred, introducing an orthogeriatrician-led service seems to be the most cost-effective service to pursue. © 2016 American Society for Bone and Mineral Research.

  5. The lifetime of the soliton in the improved Davydov model at the biological temperature 300 K for protein molecules

    NASA Astrophysics Data System (ADS)

    Xiao-feng, Pang

    We study the effects of quantum fluctuations and thermal perturbations on the lifetime of the soliton in the improved Davydov model proposed by us with two-quanta and with an added interaction. By using quantum perturbation theory, we compute the soliton lifetime for a wide ranges of parameter values relevant for protein molecules. The lifetime of the new soliton at the biological temperature 300 K is of the order of 10-10 second or τ/τ>= 500 for parameters appropriate to α-helical protein molecules. This shows clearly that the new soliton in the improved model is a viable mechanism for the bio-energy transport in the α-helix region of proteins.

  6. Lifetime effectiveness of mifamurtide addition to chemotherapy in nonmetastatic and metastatic osteosarcoma: a Markov process model analysis.

    PubMed

    Song, Hyun Jin; Lee, Jun Ah; Han, Euna; Lee, Eui-Kyung

    2015-09-01

    The mortality and progression rates in osteosarcoma differ depending on the presence of metastasis. A decision model would be useful for estimating long-term effectiveness of treatment with limited clinical trial data. The aim of this study was to explore the lifetime effectiveness of the addition of mifamurtide to chemotherapy for patients with metastatic and nonmetastatic osteosarcoma. The target population was osteosarcoma patients with or without metastasis. A Markov process model was used, whose time horizon was lifetime with a starting age of 13 years. There were five health states: disease-free (DF), recurrence, post-recurrence disease-free, post-recurrence disease-progression, and death. Transition probabilities of the starting state, DF, were calculated from the INT-0133 clinical trials for chemotherapy with and without mifamurtide. Quality-adjusted life-years (QALY) increased upon addition of mifamurtide to chemotherapy by 10.5 % (10.13 and 9.17 QALY with and without mifamurtide, respectively) and 45.2 % (7.23 and 4.98 QALY with and without mifamurtide, respectively) relative to the lifetime effectiveness of chemotherapy in nonmetastatic and metastatic osteosarcoma, respectively. Life-years gained (LYG) increased by 10.1 % (13.10 LYG with mifamurtide and 11.90 LYG without mifamurtide) in nonmetastatic patients and 42.2 % (9.43 LYG with mifamurtide and 6.63 LYG without mifamurtide) in metastatic osteosarcoma patients. The Markov model analysis showed that chemotherapy with mifamurtide improved the lifetime effectiveness compared to chemotherapy alone in both nonmetastatic and metastatic osteosarcoma. Relative effectiveness of the therapy was higher in metastatic than nonmetastatic osteosarcoma over lifetime. However, absolute lifetime effectiveness was higher in nonmetastatic than metastatic osteosarcoma.

  7. Model-free and model-based methods for dimensional metrology during the lifetime of a product

    NASA Astrophysics Data System (ADS)

    Weidner, Peter; Kasic, Alexander; Hingst, Thomas; Ehlers, Carsten; Philipp, Sylke; Marschner, Thomas; Moert, Manfred

    2008-09-01

    For future technology nodes, highly accurate dimensional metrology will become more and more important. At this stage, measuring layer thickness in planar test structures or geometrical dimensions in simplified proxy structures may be not sufficient for accurate control of highly sophisticated process steps. Model-based dimensional metrology has the potential to provide critical parameters of interest for process control in high volume manufacturing, while during process and technology development the constrained flexibility of models and the required model-building efforts may be a serious limitation. On the other hand, model-free dimensional metrology may provide sufficient flexibility for process development, while in some cases it may not be production-worthy in high volume manufacturing. This article details advantages and disadvantages of the different methods during the lifetime of a product starting from early development to high-volume production.

  8. Spatially resolved modeling of the combined effect of dislocations and grain boundaries on minority carrier lifetime in multicrystalline silicon

    NASA Astrophysics Data System (ADS)

    Stokkan, G.; Riepe, S.; Lohne, O.; Warta, W.

    2007-03-01

    A model for the combined effect of dislocations and grain boundaries on minority carrier lifetime has been developed. Lifetime varies with dislocation density, grain boundary misorientation, and the coincidence site lattice (CSL) nature of the boundaries. Minority carrier lifetime was measured with high spatial resolution (50 μm) using the carrier density imaging (CDI) technique on a silicon nitride passivated multicrystalline sample. Dislocation density was measured on the same sample by image recognition of optical microscope pictures of a Secco etched surface. Grain boundaries were then mapped and characterized by electron backscatter diffraction (EBSD). Lifetime was simulated based on the dislocation and grain boundary measurements. Parameters were chosen to match closely the simulated and measured maps. Very good two-dimensional (2D) correlation was obtained by assigning roughly equal importance to recombination at dislocations and grain boundaries. The value for the capture cross section, which gives the best correlation, is 4×10-14 cm-3. This is in the range of values reported for interstitial transition metals like, for instance, iron. It appears necessary to include also the effect of grain boundaries to explain recombination in low lifetime areas. Sub grain boundaries were particularly recombination active and are dominating the number of active grain boundaries.

  9. Determination of the atmospheric lifetime and global warming potential of sulfur hexafluoride using a three-dimensional model

    NASA Astrophysics Data System (ADS)

    Kovács, Tamás; Feng, Wuhu; Totterdill, Anna; Plane, John M. C.; Dhomse, Sandip; Gómez-Martín, Juan Carlos; Stiller, Gabriele P.; Haenel, Florian J.; Smith, Christopher; Forster, Piers M.; García, Rolando R.; Marsh, Daniel R.; Chipperfield, Martyn P.

    2017-01-01

    We have used the Whole Atmosphere Community Climate Model (WACCM), with an updated treatment of loss processes, to determine the atmospheric lifetime of sulfur hexafluoride (SF6). The model includes the following SF6 removal processes: photolysis, electron attachment and reaction with mesospheric metal atoms. The Sodankylä Ion Chemistry (SIC) model is incorporated into the standard version of WACCM to produce a new version with a detailed D region ion chemistry with cluster ions and negative ions. This is used to determine a latitude- and altitude-dependent scaling factor for the electron density in the standard WACCM in order to carry out multi-year SF6 simulations. The model gives a mean SF6 lifetime over an 11-year solar cycle (τ) of 1278 years (with a range from 1120 to 1475 years), which is much shorter than the currently widely used value of 3200 years, due to the larger contribution (97.4 %) of the modelled electron density to the total atmospheric loss. The loss of SF6 by reaction with mesospheric metal atoms (Na and K) is far too slow to affect the lifetime. We investigate how this shorter atmospheric lifetime impacts the use of SF6 to derive stratospheric age of air. The age of air derived from this shorter lifetime SF6 tracer is longer by 9 % in polar latitudes at 20 km compared to a passive SF6 tracer. We also present laboratory measurements of the infrared spectrum of SF6 and find good agreement with previous studies. We calculate the resulting radiative forcings and efficiencies to be, on average, very similar to those reported previously. Our values for the 20-, 100- and 500-year global warming potentials are 18 000, 23 800 and 31 300, respectively.

  10. Using a combined population-based and kinetic modelling approach to assess timescales and durations of magma migration activities prior to the 1669 flank eruption of Mt. Etna

    NASA Astrophysics Data System (ADS)

    Kahl, M.; Morgan, D. J.; Viccaro, M.; Dingwell, D. B.

    2015-12-01

    The March-July eruption of Mt. Etna in 1669 is ranked as one of the most destructive and voluminous eruptions of Etna volcano in historical times. To assess threats from future eruptions, a better understanding of how and over what timescales magma moved underground prior to and during the 1669 eruption is required. We present a combined population based and kinetic modelling approach [1-2] applied to 185 olivine crystals that erupted during the 1669 eruption. By means of this approach we provide, for the first time, a dynamic picture of magma mixing and magma migration activity prior to and during the 1669 flank eruption of Etna volcano. Following the work of [3] we have studied 10 basaltic lava samples (five SET1 and five SET2 samples) that were erupted from different fissures that opened between 950 and 700 m a.s.l. Following previous work [1-2] we were able to classify different populations of olivine based on their overall core and rim compositional record and the prevalent zoning type (i.e. normal vs. reverse). The core plateau compositions of the SET1 and SET2 olivines range from Fo70 up to Fo83 with a single peak at Fo75-76. The rims differ significantly and can be distinguished into two different groups. Olivine rims from the SET1 samples are generally more evolved and range from Fo50 to Fo64 with a maximum at Fo55-57. SET2 olivine rims vary between Fo65-75 with a peak at Fo69. SET1 and SET2 olivines display normal zonation with cores at Fo75-76 and diverging rim records (Fo55-57 and Fo65-75). The diverging core and rim compositions recorded in the SET1 and SET2 olivines can be attributed to magma evolution possibly in three different magmatic environments (MEs): M1 (=Fo75-76), M2 (=Fo69) and M3 (=Fo55-57) with magma transfer and mixing amongst them. The MEs established in this study differ slightly from those identified in previous works [1-2]. We note the relative lack of olivines with Fo-rich core and rim compositions indicating a major mafic magma

  11. Calculation of lifetime lung cancer risks associated with radon exposure, based on various models and exposure scenarios.

    PubMed

    Hunter, Nezahat; Muirhead, Colin R; Bochicchio, Francesco; Haylock, Richard G E

    2015-09-01

    The risk of lung cancer mortality up to 75 years of age due to radon exposure has been estimated for both male and female continuing, ex- and never-smokers, based on various radon risk models and exposure scenarios. We used risk models derived from (i) the BEIR VI analysis of cohorts of radon-exposed miners, (ii) cohort and nested case-control analyses of a European cohort of uranium miners and (iii) the joint analysis of European residential radon case-control studies. Estimates of the lifetime lung cancer risk due to radon varied between these models by just over a factor of 2 and risk estimates based on models from analyses of European uranium miners exposed at comparatively low rates and of people exposed to radon in homes were broadly compatible. For a given smoking category, there was not much difference in lifetime lung cancer risk between males and females. The estimated lifetime risk of radon-induced lung cancer for exposure to a concentration of 200 Bq m(-3) was in the range 2.98-6.55% for male continuing smokers and 0.19-0.42% for male never-smokers, depending on the model used and assuming a multiplicative relationship for the joint effect of radon and smoking. Stopping smoking at age 50 years decreases the lifetime risk due to radon by around a half relative to continuing smoking, but the risk for ex-smokers remains about a factor of 5-7 higher than that for never-smokers. Under a sub-multiplicative model for the joint effect of radon and smoking, the lifetime risk of radon-induced lung cancer was still estimated to be substantially higher for continuing smokers than for never smokers. Radon mitigation-used to reduce radon concentrations at homes-can also have a substantial impact on lung cancer risk, even for persons in their 50 s; for each of continuing smokers, ex-smokers and never-smokers, radon mitigation at age 50 would lower the lifetime risk of radon-induced lung cancer by about one-third. To maximise risk reductions, smokers in high

  12. Desired lifetime and end-of-life desires across adulthood from 20 to 90: a dual-source information model.

    PubMed

    Lang, Frieder R; Baltes, Paul B; Wagner, Gert G

    2007-09-01

    How long do people want to live, and how does scientific research on aging affect such desires? A dual-source information model proposes that aging expectations and desires are informed differently by two sources: personal experiences on the one hand, and scientific and societal influences on the other. Two studies with independent German national samples explored desires regarding length of life and end of life among adults between the ages of 20 and 90. FINDINGS ARE: First, desired lifetime is consistent at around 85 years with few age differences. Second, experimental induction of good or bad news from research on aging has little effect in Study 1. Third, interest in science has moderating effects on desired lifetime in Study 2. Fourth, there is a high prevalence of a strong desire to control the "when and how" of one's death, although only 11% of the individuals completed a living will. Findings are consistent with the dual-source information model.

  13. The Atmospheric Muon Lifetime, with the Lead Absorption Potential for Muons and References to the Standard Model of Particle Physics

    NASA Astrophysics Data System (ADS)

    Barazandeh, Cioli; Gutarra-Leon, Angel; Majewski, Walerian

    2017-01-01

    Muon is one of twelve fundamental particles and has the longest free-particle lifetime. It decays into three leptons through an exchange of weak vector bosons W +/W-. Muons are present in atmospheric secondary cosmic rays and reach the sea level. By detecting the time delay between arrival of muons and appearance of decay electrons in a scintillation detector, we will measure muon's lifetime at rest. From the lifetime we can find the ratio gw /MW of the weak coupling constant gw (a weak analog of the electric charge) to mass of the W-boson MW. Vacuum expectation value v of the Higgs field, which determines masses Standard Model (SM) particles, can be calculated as v =2MWc2/gw =(τmμc2/6π3\\hcirc)1/4mμc2 regarding muon mass mμ and muon lifetime τ only. Using the experimental value for MWc2 = 80.4 GeV, we will find weak coupling constant gw. With the SM relation e =gwsin θ√ hcε0 and experimental value of the Z0-photon weak mixing angle θ = 29o we use our muon lifetime to find the elementary electric charge e value. In this experiment we will also determine the sea level fluxes of low-energy (<160 MeV) and high-energy cosmic muons, then will shield the detector with varying thicknesses of lead plates and from the new values of fluxes find the energy-dependent muon stopping power in lead.

  14. Chasing quicksilver: modeling the atmospheric lifetime of Hg(0)(g) in the marine boundary layer at various latitudes.

    PubMed

    Hedgecock, Ian M; Pirrone, Nicola

    2004-01-01

    The lifetime of elemental mercury in the marine boundary layer(MBL) has been studied using AMCOTS (Atmospheric Mercury Chemistry Over The Sea), a box model of MBL photochemistry including aerosols and detailed mercury chemistry. Recently measured Hg(0)(g) oxidation reactions have been included, and the studies were performed as a function of latitude, time of year, boundary layer liquid water content (LWC) and cloud optical depth. The results show that Hg has the shortest lifetime when air temperatures are low and sunlight and deliquescent aerosol particles are plentiful. Thus the modeled lifetime for clear-sky conditions is actually shorter at mid-latitudes and high latitudes than near the equator, and for a given latitude and time of year, cooler temperatures enhance the rate of Hg oxidation. Under typical summer conditions (for a given latitude) of temperature and cloudiness, the lifetime (tau) of Hg(0)(g) in the MBL is calculated to be around 10 days at all latitudes between the equator and 60 degrees N. This is much shorter than the generally accepted atmospheric residence time for Hg(0)(g) of a year or more. Given the relatively stable background concentrations of Hg(0)(g) which have been measured, continual replenishment of Hg(0)(g) must take place, suggesting a "multihop" mechanism for the distribution of Hg, rather than solely aeolian transport with little or no chemical transformation between source and receptor. Inclusion of an empirical Hg(0)(g) emission factor related to insolation was used to stabilize the Hg(0)(g) concentration in the model, and the emission rates necessarily agree well with estimated emission fluxes for the open ocean.

  15. Lifetime Evaluation of Oil-immersed Power Capacitor using Conversion Factor between Model Sample and Practical Equipment

    NASA Astrophysics Data System (ADS)

    Higashiyama, Masakazu; Akiyama, Ken-Ichi; Maeda, Teruhiko; Nakamura, Shuhei; Umemura, Hiro; Hikita, Masayuki

    In this paper, the lifetime estimation method was discussed in view of Weibull distribution. For the case of power capacitor, the conversion factor between model specimen and practical equipment can be calculated by using the ratio of the electrode edge length of them and the Weibull shape parameter of the normalized V-t data obtained from the model samples. The actual failure rate of the power capacitor with PP film/capacitor-paper composite dielectric system was found to agree well with the estimated failure rate from the model samples.

  16. Evidence for an increase in the ozone photochemical lifetime in the eastern United States using a regional air quality model

    NASA Astrophysics Data System (ADS)

    Goldberg, Daniel L.; Vinciguerra, Timothy P.; Hosley, Kyle M.; Loughner, Christopher P.; Canty, Timothy P.; Salawitch, Ross J.; Dickerson, Russell R.

    2015-12-01

    Measures to control surface ozone rely on quantifying production attributable to local versus regional (upwind) emissions. Here we simulate the relative contribution of local (i.e., within a particular state) and regional sources of surface ozone in the eastern United States (66-94°W longitude) for July 2002, 2011, and 2018 using the Comprehensive Air-quality Model with Extensions (CAMx). To determine how emissions and chemistry within the domain affect the production, loss, lifetime, and transport of trace gases, we initialize our model with identical boundary conditions in each simulation. We find that the photochemical lifetime of ozone has increased as emissions have decreased. The contribution of ozone from outside the domain (boundary condition ozone, BCO3) to local surface mixing ratios increases in an absolute sense by 1-2 ppbv between 2002 and 2018 due to the longer lifetime of ozone. The photochemical lifetime of ozone lengthens because the two primary gas phase sinks for odd oxygen (Ox ≈ NO2 + O3)—attack by hydroperoxyl radicals (HO2) on ozone and formation of nitrate—weaken with decreasing pollutant emissions. The relative role of BCO3 will also increase. For example, BCO3 represents 34.5%, 38.8%, and 43.6% of surface ozone in the Baltimore, MD, region during July 2002, 2011, and 2018 means, respectively. This unintended consequence of air quality regulation impacts attainment of the National Ambient Air Quality Standard for surface ozone because the spatial and temporal scales of photochemical smog increase; the influence of pollutants transported between states and into the eastern U.S. will likely play a greater role in the future.

  17. Monte Carlo mixture model of lifetime cancer incidence risk from radiation exposure on shuttle and international space station

    NASA Technical Reports Server (NTRS)

    Peterson, L. E.; Cucinotta, F. A.; Wilson, J. W. (Principal Investigator)

    1999-01-01

    Estimating uncertainty in lifetime cancer risk for human exposure to space radiation is a unique challenge. Conventional risk assessment with low-linear-energy-transfer (LET)-based risk from Japanese atomic bomb survivor studies may be inappropriate for relativistic protons and nuclei in space due to track structure effects. This paper develops a Monte Carlo mixture model (MCMM) for transferring additive, National Institutes of Health multiplicative, and multiplicative excess cancer incidence risks based on Japanese atomic bomb survivor data to determine excess incidence risk for various US astronaut exposure profiles. The MCMM serves as an anchor point for future risk projection methods involving biophysical models of DNA damage from space radiation. Lifetime incidence risks of radiation-induced cancer for the MCMM based on low-LET Japanese data for nonleukemia (all cancers except leukemia) were 2.77 (90% confidence limit, 0.75-11.34) for males exposed to 1 Sv at age 45 and 2.20 (90% confidence limit, 0.59-10.12) for males exposed at age 55. For females, mixture model risks for nonleukemia exposed separately to 1 Sv at ages of 45 and 55 were 2.98 (90% confidence limit, 0.90-11.70) and 2.44 (90% confidence limit, 0.70-10.30), respectively. Risks for high-LET 200 MeV protons (LET=0.45 keV/micrometer), 1 MeV alpha-particles (LET=100 keV/micrometer), and 600 MeV iron particles (LET=180 keV/micrometer) were scored on a per particle basis by determining the particle fluence required for an average of one particle per cell nucleus of area 100 micrometer(2). Lifetime risk per proton was 2.68x10(-2)% (90% confidence limit, 0.79x10(-3)%-0. 514x10(-2)%). For alpha-particles, lifetime risk was 14.2% (90% confidence limit, 2.5%-31.2%). Conversely, lifetime risk per iron particle was 23.7% (90% confidence limit, 4.5%-53.0%). Uncertainty in the DDREF for high-LET particles may be less than that for low-LET radiation because typically there is very little dose-rate dependence

  18. Effects of Orbital Lifetime Reduction on the Long-Term Earth Satellite Population as Modeled by EVOLVE 4.0

    NASA Technical Reports Server (NTRS)

    Krisko, Paula H.; Opiela, John N.; Liou, Jer-Chyi; Anz-Meador, Phillip D.; Theall, Jeffrey R.

    1999-01-01

    The latest update of the NASA orbital debris environment model, EVOLVE 4.0, has been used to study the effect of various proposed debris mitigation measures, including the NASA 25-year guideline. EVOLVE 4.0, which includes updates of the NASA breakup, solar activity, and the orbit propagator models, a GEO analysis option, and non-fragmentation debris source models, allows for the statistical modeling and predicted growth of the particle population >1 mm in characteristic length in LEO and GEO orbits. The initial implementation of this &odel has been to study the sensitivity of the overall LEO debris environment to mitigation measures designed to limit the lifetime of intact objects in LEO orbits. The mitigation measures test matrix for this study included several commonly accepted testing schemes, i.e., the variance of the maximum LEO lifetime from 10 to 50 years, the date of the initial implementation of this policy, the shut off of all explosions at some specified date, and the inclusion of disposal orbits. All are timely studies in that all scenarios have been suggested by researchers and satellite operators as options for the removal of debris from LEO orbits.

  19. Modeling the expected lifetime and evolution of a deme's principal genetic sequence.

    NASA Astrophysics Data System (ADS)

    Clark, Brian

    2014-03-01

    The principal genetic sequence (PGS) is the most common genetic sequence in a deme. The PGS changes over time because new genetic sequences are created by inversions, compete with the current PGS, and a small fraction become PGSs. A set of coupled difference equations provides a description of the evolution of the PGS distribution function in an ensemble of demes. Solving the set of equations produces the survival probability of a new genetic sequence and the expected lifetime of an existing PGS as a function of inversion size and rate, recombination rate, and deme size. Additionally, the PGS distribution function is used to explain the transition pathway from old to new PGSs. We compare these results to a cellular automaton based representation of a deme and the drosophila species, D. melanogaster and D. yakuba.

  20. Simulating star clusters with the AMUSE software framework. I. Dependence of cluster lifetimes on model assumptions and cluster dissolution modes

    SciTech Connect

    Whitehead, Alfred J.; McMillan, Stephen L. W.; Vesperini, Enrico; Portegies Zwart, Simon

    2013-12-01

    We perform a series of simulations of evolving star clusters using the Astrophysical Multipurpose Software Environment (AMUSE), a new community-based multi-physics simulation package, and compare our results to existing work. These simulations model a star cluster beginning with a King model distribution and a selection of power-law initial mass functions and contain a tidal cutoff. They are evolved using collisional stellar dynamics and include mass loss due to stellar evolution. After studying and understanding that the differences between AMUSE results and results from previous studies are understood, we explored the variation in cluster lifetimes due to the random realization noise introduced by transforming a King model to specific initial conditions. This random realization noise can affect the lifetime of a simulated star cluster by up to 30%. Two modes of star cluster dissolution were identified: a mass evolution curve that contains a runaway cluster dissolution with a sudden loss of mass, and a dissolution mode that does not contain this feature. We refer to these dissolution modes as 'dynamical' and 'relaxation' dominated, respectively. For Salpeter-like initial mass functions, we determined the boundary between these two modes in terms of the dynamical and relaxation timescales.

  1. Modelled Black Carbon Radiative Forcing and Atmospheric Lifetime in AeroCom Phase II Constrained by Aircraft Observations

    SciTech Connect

    Samset, B. H.; Myhre, G.; Herber, Andreas; Kondo, Yutaka; Li, Shao-Meng; Moteki, N.; Koike, Makoto; Oshima, N.; Schwarz, Joshua P.; Balkanski, Y.; Bauer, S.; Bellouin, N.; Berntsen, T.; Bian, Huisheng; Chin, M.; Diehl, Thomas; Easter, Richard C.; Ghan, Steven J.; Iversen, T.; Kirkevag, A.; Lamarque, Jean-Francois; Lin, Guang; Liu, Xiaohong; Penner, Joyce E.; Schulz, M.; Seland, O.; Skeie, R. B.; Stier, P.; Takemura, T.; Tsigaridis, Kostas; Zhang, Kai

    2014-11-27

    Black carbon (BC) aerosols absorb solar radiation, and are generally held to exacerbate global warming through exerting a positive radiative forcing1. However, the total contribution of BC to the ongoing changes in global climate is presently under debate2-8. Both anthropogenic BC emissions and the resulting spatial and temporal distribution of BC concentration are highly uncertain2,9. In particular, long range transport and processes affecting BC atmospheric lifetime are poorly understood, leading to large estimated uncertainty in BC concentration at high altitudes and far from emission sources10. These uncertainties limit our ability to quantify both the historical, present and future anthropogenic climate impact of BC. Here we compare vertical profiles of BC concentration from four recent aircraft measurement campaigns with 13 state of the art aerosol models, and show that recent assessments may have overestimated present day BC radiative forcing. Further, an atmospheric lifetime of BC of less than 5 days is shown to be essential for reproducing observations in transport dominated remote regions. Adjusting model results to measurements in remote regions, and at high altitudes, leads to a 25% reduction in the multi-model median direct BC forcing from fossil fuel and biofuel burning over the industrial era.

  2. Collisional lifetimes of meteoroids

    NASA Astrophysics Data System (ADS)

    Soja, R. H.; Schwarzkopf, G. J.; Sommer, M.; Vaubaillon, J.; Albin, T.; Rodmann, J.; Grün, E.; Srama, R.

    2016-01-01

    Collisions of meteoroids with interplanetary dust grain fragments particles, dispersing larger particles amongst lower mass intervals. Here we use the method of Grün et al. (1985) and the IMEM interplanetary dust model to calculate the collisional lifetimes for different orbits, and for particles in different meteor showers. The timescales are usually long - of order 10^4 years for 1mm grains on Jupiter-family and Hally-type comet orbits. However, near-sun orbits particles suffer more frequent collisions and therefore have much shorter lifetimes. We discuss factors that affect the accuracy of these calculations.

  3. OL- ORBITAL LIFETIME PROGRAM

    NASA Technical Reports Server (NTRS)

    Orr, L. H.

    1994-01-01

    The Orbital Lifetime (OL) program analyzes the long-term motion of Earth-orbiting spacecraft at altitudes of up to 2500 kilometers. It models perturbations to the orbit caused by solar radiation pressure, atmospheric drag, and gravitational effects due to the sun, the moon, and Earth oblateness. OL can be used to predict the orbital lifetime and decay rate of a satellite. The atmospheric density models used in OL are the U.S. Standard Atmosphere for altitudes below 90 km and the Jacchia model for altitudes above 90 km. The Jacchia model requires solar flux and geomagnetic index for the date of orbit. An input file containing these values for 1984 to 1998 is supplied with the OL package. The solar radiation pressure calculations in OL will predict the amount of time a spacecraft is subjected to the Earth's shadow. Input to OL includes spacecraft physical characteristics, initial orbit parameters, and launch date/time. OL calculates time histories of the orbital elements, total lifetime, and decay rates. A spacecraft is considered 'down' at an altitude of 64 km. OL also generates a file of plot data which can be input to a user-supplied graphics program for lifetime plots of altitude against time. OL is written in FORTRAN 77 for interactive or batch execution and has been implemented on a DEC VAX series computer operating under VMS. This program was developed in 1985.

  4. Robust Bayesian Fluorescence Lifetime Estimation, Decay Model Selection and Instrument Response Determination for Low-Intensity FLIM Imaging

    PubMed Central

    Rowley, Mark I.; Coolen, Anthonius C. C.; Vojnovic, Borivoj; Barber, Paul R.

    2016-01-01

    We present novel Bayesian methods for the analysis of exponential decay data that exploit the evidence carried by every detected decay event and enables robust extension to advanced processing. Our algorithms are presented in the context of fluorescence lifetime imaging microscopy (FLIM) and particular attention has been paid to model the time-domain system (based on time-correlated single photon counting) with unprecedented accuracy. We present estimates of decay parameters for mono- and bi-exponential systems, offering up to a factor of two improvement in accuracy compared to previous popular techniques. Results of the analysis of synthetic and experimental data are presented, and areas where the superior precision of our techniques can be exploited in Förster Resonance Energy Transfer (FRET) experiments are described. Furthermore, we demonstrate two advanced processing methods: decay model selection to choose between differing models such as mono- and bi-exponential, and the simultaneous estimation of instrument and decay parameters. PMID:27355322

  5. Comparing lifetime emissions of natural gas and conventional fuel vehicles: an application of the generalized ANCOVA model.

    PubMed

    Deaton, M L; Winebrake, J J

    2000-02-01

    New regulations and incentives are encouraging the use of clean, alternative fuel vehicles (AFVs) in urban areas. These vehicles are seen as one option for reducing air pollution from mobile sources. However, because of the limited number of AFVs on the road, little is known about actual lifetime emissions characteristics of in-use AFVs. This study describes the use of a generalized analysis of covariance model to evaluate and compare the emissions from natural gas vehicles with emissions from reformulated gasoline vehicles. The model describes fleet-wide emissions deterioration, while also accounting for individual vehicle variability within the fleet. This ability to measure individual vehicle variability can then be used to provide realistic bounds for the emissions deterioration in individual vehicles and the fleet as a whole. In order to illustrate the use of the model, the carbon monoxide, oxides of nitrogen (NOx), non-methane hydrocarbon (NMHC), and carbon dioxide emissions characteristics of a fleet of dedicated natural gas Dodge Ram vans and a fleet of dedicated reformulated gasoline Dodge Ram vans operating in the U.S. government fleet are explored. The analysis demonstrates the utility of the statistical method and suggests a potential for natural gas Dodge Ram vans to be generally cleaner than their conventional fuel counterparts. However, in the case of NOx and NHMCs, the analysis also suggests that these emissions benefits might be reduced over the vehicle lifetime due to higher emissions deterioration rates for natural gas vehicles. As this paper is aimed at illustrating the analysis of the covariance model, the results reported herein should be considered within the context of a more comprehensive study of these data before general conclusions are possible. Generalization of these findings to other vehicle models and alternative fuel technologies is not justified without further study.

  6. Benefits and costs of substance abuse treatment programs for state prison inmates: results from a lifetime simulation model.

    PubMed

    Zarkin, Gary A; Cowell, Alexander J; Hicks, Katherine A; Mills, Michael J; Belenko, Steven; Dunlap, Laura J; Houser, Kimberly A; Keyes, Vince

    2012-06-01

    Reflecting drug use patterns and criminal justice policies throughout the 1990s and 2000s, prisons hold a disproportionate number of society's drug abusers. Approximately 50% of state prisoners meet the criteria for a diagnosis of drug abuse or dependence, but only 10% receive medically based drug treatment. Because of the link between substance abuse and crime, treating substance abusing and dependent state prisoners while incarcerated has the potential to yield substantial economic benefits. In this paper, we simulate the lifetime costs and benefits of improving prison-based substance abuse treatment and post-release aftercare for a cohort of state prisoners. Our model captures the dynamics of substance abuse as a chronic disease; estimates the benefits of substance abuse treatment over individuals' lifetimes; and tracks the costs of crime and criminal justice costs related to policing, adjudication, and incarceration. We estimate net societal benefits and cost savings to the criminal justice system of the current treatment system and five policy scenarios. We find that four of the five policy scenarios provide positive net societal benefits and cost savings to the criminal justice system relative to the current treatment system. Our study demonstrates the societal gains to improving the drug treatment system for state prisoners.

  7. Validation of three BRCA1/2 mutation-carrier probability models Myriad, BRCAPRO and BOADICEA in a population-based series of 183 German families.

    PubMed

    Schneegans, S M; Rosenberger, A; Engel, U; Sander, M; Emons, G; Shoukier, M

    2012-06-01

    Many studies have evaluated the performance of risk assessment models for BRCA1/2 mutation carrier probabilities in different populations, but to our knowledge very few studies have been conducted in the German population so far. In the recent study, we validated the performance of three risk calculation models by names BRCAPRO, Myriad and BOADICEA in 183 German families who had undergone molecular testing of mutations in BRCA1 and BRCA2 with an indication based on clinical criteria regarding their family history of cancer. The sensitivity and specificity at the conventional threshold of 10% as well as for a threshold of 20% were evaluated. The ability to discriminate between carriers and non-carriers was judged by the area under the receiver operating characteristics curve. We further focused on the performance characteristic of these models in patients carrying large genomic rearrangements as a subtype of mutations which is currently gaining increasing importance. BRCAPRO and BOADICEA performed almost equally well in our patient population, but we found a lack of agreement to Myriad. The results obtained from this study were consistent with previously published results from other population and racial/ethnic groups. We suggest using model specific decision thresholds instead of the recommended universal value of 10%. We further suggest integrating the CaGene5 software package, which includes BRCAPRO and Myriad, in the genetic counselling of German families with suspected inherited breast and ovarian cancer because of the good performance of BRCAPRO and the substantial ease of use of this software.

  8. Decision tree model for predicting long-term outcomes in children with out-of-hospital cardiac arrest: a nationwide, population-based observational study

    PubMed Central

    2014-01-01

    Introduction At hospital arrival, early prognostication for children after out-of-hospital cardiac arrest (OHCA) might help clinicians formulate strategies, particularly in the emergency department. In this study, we aimed to develop a simple and generally applicable bedside tool for predicting outcomes in children after cardiac arrest. Methods We analyzed data of 5,379 children who had undergone OHCA. The data were extracted from a prospectively recorded, nationwide, Utstein-style Japanese database. The primary endpoint was survival with favorable neurological outcome (Cerebral Performance Category (CPC) scale categories 1 and 2) at 1 month after OHCA. We developed a decision tree prediction model by using data from a 2-year period (2008 to 2009, n = 3,693), and the data were validated using external data from 2010 (n = 1,686). Results Recursive partitioning analysis for 11 predictors in the development cohort indicated that the best single predictor for CPC 1 and 2 at 1 month was the prehospital return of spontaneous circulation (ROSC). The next predictor for children with prehospital ROSC was an initial shockable rhythm. For children without prehospital ROSC, the next best predictor was a witnessed arrest. Use of a simple decision tree prediction model permitted stratification into four outcome prediction groups: good (prehospital ROSC and initial shockable rhythm), moderately good (prehospital ROSC and initial nonshockable rhythm), poor (prehospital non-ROSC and witnessed arrest) and very poor (prehospital non-ROSC and unwitnessed arrest). By using this model, we identified patient groups ranging from 0.2% to 66.2% for 1-month CPC 1 and 2 probabilities. The validated decision tree prediction model demonstrated a sensitivity of 69.7% (95% confidence interval (CI) = 58.7% to 78.9%), a specificity of 95.2% (95% CI = 94.1% to 96.2%) and an area under the receiver operating characteristic curve of 0.88 (95% CI = 0.87 to 0.90) for predicting 1-month

  9. Construction of a prediction model for type 2 diabetes mellitus in the Japanese population based on 11 genes with strong evidence of the association.

    PubMed

    Miyake, Kazuaki; Yang, Woosung; Hara, Kazuo; Yasuda, Kazuki; Horikawa, Yukio; Osawa, Haruhiko; Furuta, Hiroto; Ng, Maggie C Y; Hirota, Yushi; Mori, Hiroyuki; Ido, Keisuke; Yamagata, Kazuya; Hinokio, Yoshinori; Oka, Yoshitomo; Iwasaki, Naoko; Iwamoto, Yasuhiko; Yamada, Yuichiro; Seino, Yutaka; Maegawa, Hiroshi; Kashiwagi, Atsunori; Wang, He-Yao; Tanahashi, Toshihito; Nakamura, Naoto; Takeda, Jun; Maeda, Eiichi; Yamamoto, Ken; Tokunaga, Katsushi; Ma, Ronald C W; So, Wing-Yee; Chan, Juliana C N; Kamatani, Naoyuki; Makino, Hideichi; Nanjo, Kishio; Kadowaki, Takashi; Kasuga, Masato

    2009-04-01

    Prediction of the disease status is one of the most important objectives of genetic studies. To select the genes with strong evidence of the association with type 2 diabetes mellitus, we validated the associations of the seven candidate loci extracted in our earlier study by genotyping the samples in two independent sample panels. However, except for KCNQ1, the association of none of the remaining seven loci was replicated. We then selected 11 genes, KCNQ1, TCF7L2, CDKAL1, CDKN2A/B, IGF2BP2, SLC30A8, HHEX, GCKR, HNF1B, KCNJ11 and PPARG, whose associations with diabetes have already been reported and replicated either in the literature or in this study in the Japanese population. As no evidence of the gene-gene interaction for any pair of the 11 loci was shown, we constructed a prediction model for the disease using the logistic regression analysis by incorporating the number of the risk alleles for the 11 genes, as well as age, sex and body mass index as independent variables. Cumulative risk assessment showed that the addition of one risk allele resulted in an average increase in the odds for the disease of 1.29 (95% CI=1.25-1.33, P=5.4 x 10(-53)). The area under the receiver operating characteristic curve, an estimate of the power of the prediction model, was 0.72, thereby indicating that our prediction model for type 2 diabetes may not be so useful but has some value. Incorporation of data from additional risk loci is most likely to increase the predictive power.

  10. Predicting the lifetime of organic vapor cartridges exposed to volatile organic compound mixtures using a partial differential equations model.

    PubMed

    Vuong, François; Chauveau, Romain; Grevillot, Georges; Marsteau, Stéphanie; Silvente, Eric; Vallieres, Cécile

    2016-09-01

    In this study, equilibria, breakthrough curves, and breakthrough times were predicted for three binary mixtures of four volatile organic compounds (VOCs) using a model based on partial differential equations of dynamic adsorption coupling a mass balance, a simple Linear Driving Force (LDF) hypothesis to describe the kinetics, and the well-known Extended-Langmuir (EL) equilibrium model. The model aims to predict with a limited complexity, the BTCs of respirator cartridges exposed to binary vapor mixtures from equilibria and kinetics data obtained from single component. In the model, multicomponent mass transfer was simplified to use only single dynamic adsorption data. The EL expression used in this study predicted equilibria with relatively good accuracy for acetone/ethanol and ethanol/cyclohexane mixtures, but the prediction of cyclohexane uptake when mixed with heptane is less satisfactory. The BTCs given by the model were compared to experimental BTCs to determine the accuracy of the model and the impact of the approximation on mass transfer coefficients. From BTCs, breakthrough times at 10% of the exposure concentration t10% were determined. All t10% were predicted within 20% of the experimental values, and 63% of the breakthrough times were predicted within a 10% error. This study demonstrated that a simple mass balance combined with kinetic approximations is sufficient to predict lifetime for respirator cartridges exposed to VOC mixtures. It also showed that a commonly adopted approach to describe multicomponent adsorption based on volatility of VOC rather than adsorption equilibrium greatly overestimated the breakthrough times.

  11. How patch size and refuge availability change interaction strength and population dynamics: a combined individual- and population-based modeling experiment

    PubMed Central

    Brose, Ulrich; Meyer, Katrin

    2017-01-01

    Knowledge on how functional responses (a measurement of feeding interaction strength) are affected by patch size and habitat complexity (represented by refuge availability) is crucial for understanding food-web stability and subsequently biodiversity. Due to their laborious character, it is almost impossible to carry out systematic empirical experiments on functional responses across wide gradients of patch sizes and refuge availabilities. Here we overcame this issue by using an individual-based model (IBM) to simulate feeding experiments. The model is based on empirically measured traits such as body-mass dependent speed and capture success. We simulated these experiments in patches ranging from sizes of petri dishes to natural patches in the field. Moreover, we varied the refuge availability within the patch independently of patch size, allowing for independent analyses of both variables. The maximum feeding rate (the maximum number of prey a predator can consume in a given time frame) is independent of patch size and refuge availability, as it is the physiological upper limit of feeding rates. Moreover, the results of these simulations revealed that a type III functional response, which is known to have a stabilizing effect on population dynamics, fitted the data best. The half saturation density (the prey density where a predator consumes half of its maximum feeding rate) increased with refuge availability but was only marginally influenced by patch size. Subsequently, we investigated how patch size and refuge availability influenced stability and coexistence of predator-prey systems. Following common practice, we used an allometric scaled Rosenzweig–MacArthur predator-prey model based on results from our in silico IBM experiments. The results suggested that densities of both populations are nearly constant across the range of patch sizes simulated, resulting from the constant interaction strength across the patch sizes. However, constant densities with

  12. How patch size and refuge availability change interaction strength and population dynamics: a combined individual- and population-based modeling experiment.

    PubMed

    Li, Yuanheng; Brose, Ulrich; Meyer, Katrin; Rall, Björn C

    2017-01-01

    Knowledge on how functional responses (a measurement of feeding interaction strength) are affected by patch size and habitat complexity (represented by refuge availability) is crucial for understanding food-web stability and subsequently biodiversity. Due to their laborious character, it is almost impossible to carry out systematic empirical experiments on functional responses across wide gradients of patch sizes and refuge availabilities. Here we overcame this issue by using an individual-based model (IBM) to simulate feeding experiments. The model is based on empirically measured traits such as body-mass dependent speed and capture success. We simulated these experiments in patches ranging from sizes of petri dishes to natural patches in the field. Moreover, we varied the refuge availability within the patch independently of patch size, allowing for independent analyses of both variables. The maximum feeding rate (the maximum number of prey a predator can consume in a given time frame) is independent of patch size and refuge availability, as it is the physiological upper limit of feeding rates. Moreover, the results of these simulations revealed that a type III functional response, which is known to have a stabilizing effect on population dynamics, fitted the data best. The half saturation density (the prey density where a predator consumes half of its maximum feeding rate) increased with refuge availability but was only marginally influenced by patch size. Subsequently, we investigated how patch size and refuge availability influenced stability and coexistence of predator-prey systems. Following common practice, we used an allometric scaled Rosenzweig-MacArthur predator-prey model based on results from our in silico IBM experiments. The results suggested that densities of both populations are nearly constant across the range of patch sizes simulated, resulting from the constant interaction strength across the patch sizes. However, constant densities with

  13. Why do general circulation models overestimate the aerosol cloud lifetime effect? A case study comparing CAM5 and a CRM

    DOE PAGES

    Zhou, Cheng; Penner, Joyce E.

    2017-01-02

    Observation-based studies have shown that the aerosol cloud lifetime effect or the increase of cloud liquid water path (LWP) with increased aerosol loading may have been overestimated in climate models. Here, we simulate shallow warm clouds on 27 May 2011 at the southern Great Plains (SGP) measurement site established by the Department of Energy's (DOE) Atmospheric Radiation Measurement (ARM) program using a single-column version of a global climate model (Community Atmosphere Model or CAM) and a cloud resolving model (CRM). The LWP simulated by CAM increases substantially with aerosol loading while that in the CRM does not. The increase of LWP inmore » CAM is caused by a large decrease of the autoconversion rate when cloud droplet number increases. In the CRM, the autoconversion rate is also reduced, but this is offset or even outweighed by the increased evaporation of cloud droplets near the cloud top, resulting in an overall decrease in LWP. Our results suggest that climate models need to include the dependence of cloud top growth and the evaporation/condensation process on cloud droplet number concentrations.« less

  14. Why do general circulation models overestimate the aerosol cloud lifetime effect? A case study comparing CAM5 and a CRM

    NASA Astrophysics Data System (ADS)

    Zhou, Cheng; Penner, Joyce E.

    2017-01-01

    Observation-based studies have shown that the aerosol cloud lifetime effect or the increase of cloud liquid water path (LWP) with increased aerosol loading may have been overestimated in climate models. Here, we simulate shallow warm clouds on 27 May 2011 at the southern Great Plains (SGP) measurement site established by the Department of Energy's (DOE) Atmospheric Radiation Measurement (ARM) program using a single-column version of a global climate model (Community Atmosphere Model or CAM) and a cloud resolving model (CRM). The LWP simulated by CAM increases substantially with aerosol loading while that in the CRM does not. The increase of LWP in CAM is caused by a large decrease of the autoconversion rate when cloud droplet number increases. In the CRM, the autoconversion rate is also reduced, but this is offset or even outweighed by the increased evaporation of cloud droplets near the cloud top, resulting in an overall decrease in LWP. Our results suggest that climate models need to include the dependence of cloud top growth and the evaporation/condensation process on cloud droplet number concentrations.

  15. Modelling impacts of performance on the probability of reproducing, and thereby on productive lifespan, allow prediction of lifetime efficiency in dairy cows.

    PubMed

    Phuong, H N; Blavy, P; Martin, O; Schmidely, P; Friggens, N C

    2016-01-01

    Reproductive success is a key component of lifetime efficiency - which is the ratio of energy in milk (MJ) to energy intake (MJ) over the lifespan, of cows. At the animal level, breeding and feeding management can substantially impact milk yield, body condition and energy balance of cows, which are known as major contributors to reproductive failure in dairy cattle. This study extended an existing lifetime performance model to incorporate the impacts that performance changes due to changing breeding and feeding strategies have on the probability of reproducing and thereby on the productive lifespan, and thus allow the prediction of a cow's lifetime efficiency. The model is dynamic and stochastic, with an individual cow being the unit modelled and one day being the unit of time. To evaluate the model, data from a French study including Holstein and Normande cows fed high-concentrate diets and data from a Scottish study including Holstein cows selected for high and average genetic merit for fat plus protein that were fed high- v. low-concentrate diets were used. Generally, the model consistently simulated productive and reproductive performance of various genotypes of cows across feeding systems. In the French data, the model adequately simulated the reproductive performance of Holsteins but significantly under-predicted that of Normande cows. In the Scottish data, conception to first service was comparably simulated, whereas interval traits were slightly under-predicted. Selection for greater milk production impaired the reproductive performance and lifespan but not lifetime efficiency. The definition of lifetime efficiency used in this model did not include associated costs or herd-level effects. Further works should include such economic indicators to allow more accurate simulation of lifetime profitability in different production scenarios.

  16. Bacterial ice nuclei impact cloud lifetime and radiative properties and reduce atmospheric heat loss in the BRAMS simulation model

    NASA Astrophysics Data System (ADS)

    Costa, Tassio S.; Gonçalves, Fábio L. T.; Yamasoe, Marcia A.; Martins, Jorge A.; Morris, Cindy E.

    2014-08-01

    This study examines the effect of the bacterial species Pseudomonas syringae acting as ice nuclei (IN) on cloud properties to understand its impact on local radiative budget and heating rates. These bacteria may become active IN at temperatures as warm as -2 °C. Numerical simulations were developed using the Brazilian Regional Atmospheric Model System (BRAMS). To investigate the isolated effect of bacterial IN, four scenarios were created considering only homogeneous and bacterial ice nucleation, with 1, 10 and 100 IN per cubic meter of cloud volume and one with no bacteria. Moreover, two other scenarios were generated: the BRAMS default parameterization and its combination with bacterial IN. The model reproduced a strong convective cell over São Paulo on 3 March 2003. Results showed that bacterial IN may change cloud evolution as well as its microphysical properties, which in turn influence cloud radiative properties. For example, the reflected shortwave irradiance over an averaged domain in a scenario considering bacterial IN added to the BRAMS default parameterization was 14% lower than if bacteria were not considered. Heating rates can also be impacted, especially due to differences in cloud lifetime. Results suggest that the omission of bacterial IN in numerical models, including global cloud models, could neglect relevant ice nucleation processes that potentially influence cloud radiative properties.

  17. Constraints from Airborne (210)Pb Observations on Aerosol Scavenging and Lifetime in a Global Chemical Transport Model

    NASA Technical Reports Server (NTRS)

    Zhang, Bo; Liu, Hongyu; Crawford, James H.; Fairlie, Duncan T.; Chen, Gao; Dibb, Jack E.; Shah, Viral; Sulprizio, Melissa P.; Yantosca, Robert M.

    2016-01-01

    Lead-210 distribution and lifetime in the atmosphere are not sensitive to ice in-cloud scavenging in convective updraft. Ice in-cloud scavenging in stratiform clouds reduce tropospheric (210)Pb lifetime by approximately 1 day and results in better agreements with observed surface observations and aircraft measured profiles. However, the process results in significant underestimate of (210)Pb in UT/LS.

  18. Expectation maximization-based likelihood inference for flexible cure rate models with Weibull lifetimes.

    PubMed

    Balakrishnan, Narayanaswamy; Pal, Suvra

    2016-08-01

    Recently, a flexible cure rate survival model has been developed by assuming the number of competing causes of the event of interest to follow the Conway-Maxwell-Poisson distribution. This model includes some of the well-known cure rate models discussed in the literature as special cases. Data obtained from cancer clinical trials are often right censored and expectation maximization algorithm can be used in this case to efficiently estimate the model parameters based on right censored data. In this paper, we consider the competing cause scenario and assuming the time-to-event to follow the Weibull distribution, we derive the necessary steps of the expectation maximization algorithm for estimating the parameters of different cure rate survival models. The standard errors of the maximum likelihood estimates are obtained by inverting the observed information matrix. The method of inference developed here is examined by means of an extensive Monte Carlo simulation study. Finally, we illustrate the proposed methodology with a real data on cancer recurrence.

  19. Microstructurally based thermomechanical fatigue lifetime model of solder joints for electronic applications

    SciTech Connect

    Frear, D.R.; Rashid, M.M.; Burchett, S.N.

    1993-07-01

    We present a new methodology for predicting the fatigue life of solder joints for electronics applications. This approach involves integration of experimental and computational techniques. The first stage involves correlating the manufacturing and processing parameters with the starting microstructure of the solder joint. The second stage involves a series of experiments that characterize the evolution of the microstructure during thermal cycling. The third stage consists of a computer modeling and simulation effort that utilizes the starting microstructure and experimental data to produce a reliability prediction of the solder joint. This approach is an improvement over current methodologies because it incorporates the microstructure and properties of the solder directly into the model and allows these properties to evolve as the microstructure changes during fatigue.

  20. Microstructurally based thermomechanical fatigue lifetime model of solder joints for electronic applications

    NASA Astrophysics Data System (ADS)

    Frear, D. R.; Rashid, M. M.; Burchett, S. N.

    We present a new methodology for predicting the fatigue life of solder joints for electronics applications. This approach involves integration of experimental and computational techniques. The first stage involves correlating the manufacturing and processing parameters with the starting microstructure of the solder joint. The second stage involves a series of experiments that characterize the evolution of the microstructure during thermal cycling. The third stage consists of a computer modeling and simulation effort that utilizes the starting microstructure and experimental data to produce a reliability prediction of the solder joint. This approach is an improvement over current methodologies because it incorporates the microstructure and properties of the solder directly into the model and allows these properties to evolve as the microstructure changes during fatigue.

  1. A population-based Habitable Zone perspective

    NASA Astrophysics Data System (ADS)

    Zsom, Andras

    2015-08-01

    What can we tell about exoplanet habitability if currently only the stellar properties, planet radius, and the incoming stellar flux are known? The Habitable Zone (HZ) is the region around stars where planets can harbor liquid water on their surfaces. The HZ is traditionally conceived as a sharp region around the star because it is calculated for one planet with specific properties e.g., Earth-like or desert planets , or rocky planets with H2 atmospheres. Such planet-specific approach is limiting because the planets’ atmospheric and geophysical properties, which influence the surface climate and the presence of liquid water, are currently unknown but expected to be diverse.A statistical HZ description is outlined which does not select one specific planet type. Instead the atmospheric and surface properties of exoplanets are treated as random variables and a continuous range of planet scenarios are considered. Various probability density functions are assigned to each observationally unconstrained random variable, and a combination of Monte Carlo sampling and climate modeling is used to generate synthetic exoplanet populations with known surface climates. Then, the properties of the liquid water bearing subpopulation is analyzed.Given our current observational knowledge of small exoplanets, the HZ takes the form of a weakly-constrained but smooth probability function. The model shows that the HZ has an inner edge: it is unlikely that planets receiving two-three times more stellar radiation than Earth can harbor liquid water. But a clear outer edge is not seen: a planet that receives a fraction of Earth's stellar radiation (1-10%) can be habitable, if the greenhouse effect of the atmosphere is strong enough. The main benefit of the population-based approach is that it will be refined over time as new data on exoplanets and their atmospheres become available.

  2. Lifetimes of lunar satellite orbits

    NASA Technical Reports Server (NTRS)

    Meyer, Kurt W.; Buglia, James J.; Desai, Prasun N.

    1994-01-01

    The Space Exploration Initiative has generated a renewed interest in lunar mission planning. The lunar missions currently under study, unlike the Apollo missions, involve long stay times. Several lunar gravity models have been formulated, but mission planners do not have enough confidence in the proposed models to conduct detailed studies of missions with long stay times. In this report, a particular lunar gravitational model, the Ferrari 5 x 5 model, was chosen to determine the lifetimes for 100-km and 300-km perilune altitude, near-circular parking orbits. The need to analyze orbital lifetimes for a large number of initial orbital parameters was the motivation for the formulation of a simplified gravitational model from the original model. Using this model, orbital lifetimes were found to be heavily dependent on the initial conditions of the nearly circular orbits, particularly the initial inclination and argument of perilune. This selected model yielded lifetime predictions of less than 40 days for some orbits, and other orbits had lifetimes exceeding a year. Although inconsistencies and limitations are inherent in all existing lunar gravity models, primarily because of a lack of information about the far side of the moon, the methods presented in this analysis are suitable for incorporating the moon's nonspherical gravitational effects on the preliminary design level for future lunar mission planning.

  3. Analytic solutions to modelling exponential and harmonic functions using Chebyshev polynomials: fitting frequency-domain lifetime images with photobleaching.

    PubMed

    Malachowski, George C; Clegg, Robert M; Redford, Glen I

    2007-12-01

    A novel approach is introduced for modelling linear dynamic systems composed of exponentials and harmonics. The method improves the speed of current numerical techniques up to 1000-fold for problems that have solutions of multiple exponentials plus harmonics and decaying components. Such signals are common in fluorescence microscopy experiments. Selective constraints of the parameters being fitted are allowed. This method, using discrete Chebyshev transforms, will correctly fit large volumes of data using a noniterative, single-pass routine that is fast enough to analyse images in real time. The method is applied to fluorescence lifetime imaging data in the frequency domain with varying degrees of photobleaching over the time of total data acquisition. The accuracy of the Chebyshev method is compared to a simple rapid discrete Fourier transform (equivalent to least-squares fitting) that does not take the photobleaching into account. The method can be extended to other linear systems composed of different functions. Simulations are performed and applications are described showing the utility of the method, in particular in the area of fluorescence microscopy.

  4. Momentum-Dependent Lifetime Broadening of Electron Energy Loss Spectra: A Self-Consistent Coupled-Plasmon Model.

    PubMed

    Bourke, J D; Chantler, C T

    2015-02-05

    The complex dielectric function and associated energy loss spectrum of a condensed matter system is a fundamental material parameter that determines both the optical and electronic scattering behavior of the medium. The common representation of the electron energy loss function (ELF) is interpreted as the susceptibility of a system to a single- or bulk-electron (plasmon) excitation at a given energy and momentum and is commonly derived as a summation of noninteracting free-electron resonances with forms constrained by adherence to some externally determined optical standard. This work introduces a new causally constrained momentum-dependent broadening theory, permitting a more physical representation of optical and electronic resonances that agrees more closely with both optical attenuation and electron scattering data. We demonstrate how the momentum dependence of excitation resonances may be constrained uniquely by utilizing a coupled-plasmon model, in which high-energy excitations are able to relax into lower-energy excitations within the medium. This enables a robust and fully self-consistent theory with no free or fitted parameters that reveals additional physical insight not present in previous work. The new developments are applied to the scattering behavior of solid molybdenum and aluminum. We find that plasmon and single-electron lifetimes are significantly affected by the presence of alternate excitation channels and show for molybdenum that agreement with high-precision electron inelastic mean free path data is dramatically improved for energies above 20 eV.

  5. Lactation and cardiovascular risk factors in mothers in a population-based study: the HUNT-study

    PubMed Central

    2012-01-01

    Background Lactation has beneficial short term effects on maternal metabolic health, but the long term effects are less well known. Methods We studied the association between lifetime duration of lactation and cardiovascular risk factors in mothers later in life among 21,368 parous women aged 20 to 85 years attending the second Nord-Trøndelag Health Study (HUNT2) in 1995–1997, Norway, a cross-sectional population-based study. General linear modelling was used to calculate mean values of known cardiovascular risk factor levels in five categories of lifetime duration of lactation. Logistic regression was conducted to estimate odds ratios of hypertension, obesity and diabetes. Results Among women aged 50 years or younger, lifetime duration of lactation was significantly and inversely associated with body mass index (P-trend, < 0.001), waist circumference (P-trend, < 0.001), systolic and diastolic blood pressure (both P-trends, < 0.001), and serum levels of triglycerides, total cholesterol and low density lipoprotein cholesterol (all P-trends, < 0.001) after adjustment for covariates. Parous women aged 50 years or younger who had never lactated had higher prevalence of hypertension, obesity and diabetes. In this age group, compared to women who had lactated for 24 months or more, parous women who had never lactated had an OR for hypertension of 1.88 (95% CI 1.41, 2.51), an OR for obesity of 3.37 (95% CI 2.51, 4.51) and an OR for diabetes of 5.87 (95% CI 2.25, 15.3). Among women older than 50 years there were no clear associations. Conclusion Lifetime duration of lactation was associated with long term reduced cardiovascular risk levels in mothers aged 50 years or younger. PMID:22713515

  6. Physical comorbidities in men with mood and anxiety disorders: a population-based study

    PubMed Central

    2013-01-01

    Background The mind-body nexus has been a topic of growing interest. Further data are however required to understand the specific relationship between mood and anxiety disorders and individual physical health conditions, and to verify whether these psychiatric disorders are linked to overall medical burden. Methods This study examined data collected from 942 men, 20 to 97 years old, participating in the Geelong Osteoporosis Study. A lifetime history of mood and anxiety disorders was identified using the Structured Clinical Interview for DSM-IV-TR Research Version, Non-patient edition (SCID-I/NP). The presence of medical conditions (lifetime) was self-reported and confirmed by medical records, medication use or clinical data. Anthropometric measurements and socioeconomic status (SES) were determined and information on medication use and lifestyle was obtained via questionnaire. Logistic regression models were used to test the associations. Results After adjustment for age, socioeconomic status, and health risk factors (body mass index, physical activity and smoking), mood disorders were associated with gastro oesophageal reflux disease (GORD), recurrent headaches, blackouts and/or epilepsy, liver disorders and pulmonary disease in older people, whilst anxiety disorders were significantly associated with thyroid, GORD and other gastrointestinal disorders, and psoriasis. Increased odds of high medical burden were associated with both mood and anxiety disorders. Conclusions Our study provides further population-based evidence supporting the link between mental and physical illness in men. Understanding these associations is not only necessary for individual management, but also to inform the delivery of health promotion messages and health care. PMID:23618390

  7. Cost-effectiveness analysis of population-based screening of hepatocellular carcinoma: Comparing ultrasonography with two-stage screening

    PubMed Central

    Kuo, Ming-Jeng; Chen, Hsiu-Hsi; Chen, Chi-Ling; Fann, Jean Ching-Yuan; Chen, Sam Li-Sheng; Chiu, Sherry Yueh-Hsia; Lin, Yu-Min; Liao, Chao-Sheng; Chang, Hung-Chuen; Lin, Yueh-Shih; Yen, Amy Ming-Fang

    2016-01-01

    AIM: To assess the cost-effectiveness of two population-based hepatocellular carcinoma (HCC) screening programs, two-stage biomarker-ultrasound method and mass screening using abdominal ultrasonography (AUS). METHODS: In this study, we applied a Markov decision model with a societal perspective and a lifetime horizon for the general population-based cohorts in an area with high HCC incidence, such as Taiwan. The accuracy of biomarkers and ultrasonography was estimated from published meta-analyses. The costs of surveillance, diagnosis, and treatment were based on a combination of published literature, Medicare payments, and medical expenditure at the National Taiwan University Hospital. The main outcome measure was cost per life-year gained with a 3% annual discount rate. RESULTS: The results show that the mass screening using AUS was associated with an incremental cost-effectiveness ratio of USD39825 per life-year gained, whereas two-stage screening was associated with an incremental cost-effectiveness ratio of USD49733 per life-year gained, as compared with no screening. Screening programs with an initial screening age of 50 years old and biennial screening interval were the most cost-effective. These findings were sensitive to the costs of screening tools and the specificity of biomarker screening. CONCLUSION: Mass screening using AUS is more cost effective than two-stage biomarker-ultrasound screening. The most optimal strategy is an initial screening age at 50 years old with a 2-year inter-screening interval. PMID:27022228

  8. Predicting successful aging in a population-based sample of georgia centenarians.

    PubMed

    Arnold, Jonathan; Dai, Jianliang; Nahapetyan, Lusine; Arte, Ankit; Johnson, Mary Ann; Hausman, Dorothy; Rodgers, Willard L; Hensley, Robert; Martin, Peter; Macdonald, Maurice; Davey, Adam; Siegler, Ilene C; Jazwinski, S Michal; Poon, Leonard W

    2010-01-01

    Used a population-based sample (Georgia Centenarian Study, GCS), to determine proportions of centenarians reaching 100 years as (1) survivors (43%) of chronic diseases first experienced between 0-80 years of age, (2) delayers (36%) with chronic diseases first experienced between 80-98 years of age, or (3) escapers (17%) with chronic diseases only at 98 years of age or older. Diseases fall into two morbidity profiles of 11 chronic diseases; one including cardiovascular disease, cancer, anemia, and osteoporosis, and another including dementia. Centenarians at risk for cancer in their lifetime tended to be escapers (73%), while those at risk for cardiovascular disease tended to be survivors (24%), delayers (39%), or escapers (32%). Approximately half (43%) of the centenarians did not experience dementia. Psychiatric disorders were positively associated with dementia, but prevalence of depression, anxiety, and psychoses did not differ significantly between centenarians and an octogenarian control group. However, centenarians were higher on the Geriatric Depression Scale (GDS) than octogenarians. Consistent with our model of developmental adaptation in aging, distal life events contribute to predicting survivorship outcome in which health status as survivor, delayer, or escaper appears as adaptation variables late in life.

  9. Population bases and the 2011 Census.

    PubMed

    Smallwood, Steve

    2011-01-01

    In an increasingly complex society there are a number of different population definitions that can be relevant for users, beyond the standard definition used in counting the population. This article describes the enumeration base for the 2011 Census and how alternative population outputs may be produced. It provides a background as to how the questions on the questionnaire were decided upon and how population bases can be constructed from the Census. Similarities and differences between the information collected across the three UK Censuses (England and Wales, Scotland and Northern Ireland) are discussed. Finally, issues around estimating the population on alternative bases are presented.

  10. Partial likelihood estimation of IRT models with censored lifetime data: an application to mental disorders in the ESEMeD surveys.

    PubMed

    Forero, Carlos G; Almansa, Josué; Adroher, Núria D; Vermunt, Jeroen K; Vilagut, Gemma; De Graaf, Ron; Haro, Josep-Maria; Alonso Caballero, Jordi

    2014-07-01

    Developmental studies of mental disorders based on epidemiological data are often based on cross-sectional retrospective surveys. Under such designs, observations are right-censored, causing underestimation of lifetime prevalences and correlations, and inducing bias in latent trait models on the observations. In this paper we propose a Partial Likelihood (PL) method to estimate unbiased IRT models of lifetime predisposition to develop a certain outcome. A two-step estimation procedure corrects the IRT likelihood of outcome appearance with a function depending on (a) projected outcome frequencies at the end of the risk period, and (b) outcome censoring status at the time of the observation. Simulation results showed that the PL method yielded good recovery of true frequencies and intercepts. Slopes were best estimated when events were sufficiently correlated. When PL is applied to lifetime mental health disorders (assessed in the ESEMeD project surveys), estimated univariate prevalences were, on average, 1.4 times above raw estimates, and 2.06 higher in the case of bivariate prevalences.

  11. Quantification of the Metabolic State in Cell-Model of Parkinson’s Disease by Fluorescence Lifetime Imaging Microscopy

    PubMed Central

    Chakraborty, Sandeep; Nian, Fang-Shin; Tsai, Jin-Wu; Karmenyan, Artashes; Chiou, Arthur

    2016-01-01

    Intracellular endogenous fluorescent co-enzymes, reduced nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD), play a pivotal role in cellular metabolism; quantitative assessment of their presence in living cells can be exploited to monitor cellular energetics in Parkinson’s disease (PD), a neurodegenerative disorder. Here, we applied two-photon fluorescence lifetime imaging microscopy (2P-FLIM) to noninvasively measure the fluorescence lifetime components of NADH and FAD, and their relative contributions in MPP+ (1-methyl-4-phenylpyridinium) treated neuronal cells, derived from PC12 cells treated with nerve growth factor (NGF), to mimic PD conditions. A systematic FLIM data analysis showed a statistically significant (p < 0.001) decrease in the fluorescence lifetime of both free and protein-bound NADH, as well as free and protein-bound FAD in MPP+ treated cells. On the relative contributions of the free and protein-bound NADH and FAD to the life time, however, both the free NADH contribution and the corresponding protein-bound FAD contribution increase significantly (p < 0.001) in MPP+ treated cells, compared to control cells. These results, which indicate a shift in energy production in the MPP+ treated cells from oxidative phosphorylation towards anaerobic glycolysis, can potentially be used as cellular metabolic metrics to assess the condition of PD at the cellular level. PMID:26758390

  12. Lifetime measurements in 100Ru

    NASA Astrophysics Data System (ADS)

    Konstantinopoulos, T.; Petkov, P.; Goasduff, A.; Arici, T.; Astier, A.; Atanasova, L.; Axiotis, M.; Bonatsos, D.; Detistov, P.; Dewald, A.; Eller, M. J.; Foteinou, V.; Gargano, A.; Georgiev, G.; Gladnishki, K.; Gottardo, A.; Harissopulos, S.; Hess, H.; Kaim, S.; Kocheva, D.; Kusoglu, A.; Lagoyannis, A.; Ljungvall, J.; Lutter, R.; Matea, I.; Melon, B.; Mertzimekis, T. J.; Nannini, A.; Petrache, C. M.; Petrovici, A.; Provatas, G.; Reiter, P.; Rocchini, M.; Roccia, S.; Seidlitz, M.; Siebeck, B.; Suzuki, D.; Warr, N.; De Witte, H.; Zerrouki, T.

    2017-01-01

    The nucleus 100Ru appears to be a good candidate for the E(5) critical point symmetry which describes the U(5)-SO(6) shape phase transition. To investigate this point with respect to the electromagnetic transition strengths, lifetime measurements of its yrast states have been performed using the recoil distance Doppler shift technique as well as the Doppler shift attenuation method. As a result, the lifetimes of the yrast 2+, 4+, and 8+ states were determined. The deduced transition strengths are compared to the E(5) predictions as well as to the results of excited Vampir and shell-model calculations.

  13. Lifetime measurements in 180Pt

    NASA Astrophysics Data System (ADS)

    Chen, Q. M.; Wu, X. G.; Chen, Y. S.; Li, C. B.; Gao, Z. C.; Li, G. S.; Chen, F. Q.; He, C. Y.; Zheng, Y.; Hu, S. P.; Zhong, J.; Wu, Y. H.; Li, H. W.; Luo, P. W.

    2016-04-01

    Lifetimes of the yrast states in 180Pt have been measured from 4+ to 8+ using the recoil distance Doppler-shift technique in the coincidence mode. These states were populated by the reaction 156Gd(28Si,4 n )180Pt at a beam energy of 144 MeV. The differential decay curve method was applied to determine the lifetimes from experimental coincidence data. The B (E 2 ) values extracted from lifetimes increase with increasing spin, implying rotor behavior, but do not show the typical shape coexistence where the B (E 2 ) values present a rapid increase at very low spins. Calculations based on the triaxial projected shell model were performed for the yrast states in 180Pt and the results of both energies and E 2 transition probabilities reproduce the experimental data very well. The result also shows that a better description of the yrast band in 180Pt requires consideration of the γ degree of freedom.

  14. Atmospheric lifetimes and Ozone Depletion Potentials of trans-1-chloro-3,3,3-trifluoropropylene and trans-1,2-dichloroethylene in a three-dimensional model

    NASA Astrophysics Data System (ADS)

    Patten, K. O.; Wuebbles, D. J.

    2010-11-01

    The chloroalkenes trans-1-chloro-3,3,3-trifluoropropylene (tCFP) and trans-1,2-dichloroethylene (tDCE) have been proposed as candidate replacements for other compounds in current use that cause concerns regarding potential environmental effects including destruction of stratospheric ozone. Because tCFP and tDCE contain chlorine atoms, the effects of these short-lived compounds on stratospheric ozone must be established. In this study, we derive the atmospheric lifetimes and Ozone Depletion Potentials (ODPs) for tCFP and for tDCE assuming emissions from land surfaces at latitudes 30° N to 60° N using the MOZART 3 three-dimensional model of atmospheric chemistry and physics. 53% of the ozone loss due to tCFP and 98% of the ozone loss due to tDCE take place in the troposphere, rather than in the stratosphere as generally expected from longer-lived chlorocarbons. The atmospheric lifetime of tCFP against chemical reaction is 40.4 days, and its ODP is quite small at 0.00034. The tDCE atmospheric lifetime is 12.7 days, and its ODP is 0.00024, which is the lowest ODP found for any chlorocarbon we have studied. Our study suggests that chlorine from tCFP and tDCE are unlikely to affect ozone at quantities likely to be emitted to the atmosphere.

  15. Atmospheric lifetimes and ozone depletion potentials of trans-1-chloro-3,3,3-trifluoropropylene and trans-1,2-dichloroethylene in a three-dimensional model

    NASA Astrophysics Data System (ADS)

    Patten, K. O.; Wuebbles, D. J.

    2010-07-01

    The chloroalkenes trans-1-chloro-3,3,3-trifluoropropylene (tCFP) and trans-1,2-dichloroethylene (tDCE) have been proposed as candidate replacements for other compounds in current use that cause concerns regarding potential environmental effects including destruction of stratospheric ozone. Because tCFP and tDCE contain chlorine atoms, the effects of these short-lived compounds on stratospheric ozone must be established. In this study, we derive the atmospheric lifetimes and Ozone Depletion Potentials (ODPs) for tCFP and for tDCE assuming emissions from land surfaces at latitudes 30° N to 60° N using the MOZART 3 three-dimensional model of atmospheric chemistry and physics. Both tCFP and tDCE are shown to primarily affect ozone in the troposphere, rather than in the stratosphere as generally expected from longer-lived chlorocarbons. The atmospheric lifetime of tCFP against chemical reaction is 40.4 days, and its ODP is quite small at 0.00034. The tDCE atmospheric lifetime is 12.7 days, and its ODP is 0.00024, which is the lowest ODP found for any chlorocarbon we have studied. Our study suggests that chlorine from tCFP and tDCE are unlikely to significantly affect ozone at quantities likely to be emitted to the atmosphere.

  16. The costs of inequality: whole-population modelling study of lifetime inpatient hospital costs in the English National Health Service by level of neighbourhood deprivation

    PubMed Central

    Doran, Tim; Cookson, Richard

    2016-01-01

    Background There are substantial socioeconomic inequalities in both life expectancy and healthcare use in England. In this study, we describe how these two sets of inequalities interact by estimating the social gradient in hospital costs across the life course. Methods Hospital episode statistics, population and index of multiple deprivation data were combined at lower-layer super output area level to estimate inpatient hospital costs for 2011/2012 by age, sex and deprivation quintile. Survival curves were estimated for each of the deprivation groups and used to estimate expected annual costs and cumulative lifetime costs. Results A steep social gradient was observed in overall inpatient hospital admissions, with rates ranging from 31 298/100 000 population in the most affluent fifth of areas to 43 385 in the most deprived fifth. This gradient was steeper for emergency than for elective admissions. The total cost associated with this inequality in 2011/2012 was £4.8 billion. A social gradient was also observed in the modelled lifetime costs where the lower life expectancy was not sufficient to outweigh the higher average costs in the more deprived populations. Lifetime costs for women were 14% greater than for men, due to higher costs in the reproductive years and greater life expectancy. Conclusions Socioeconomic inequalities result in increased morbidity and decreased life expectancy. Interventions to reduce inequality and improve health in more deprived neighbourhoods have the potential to save money for health systems not only within years but across peoples’ entire lifetimes, despite increased costs due to longer life expectancies. PMID:27189975

  17. Population-Based Smoking Cessation Strategies

    PubMed Central

    2010-01-01

    Executive Summary Objective The objective of this report was to provide the Ministry of Health Promotion (MHP) with a summary of existing evidence-based reviews of the clinical and economic outcomes of population-based smoking cessation strategies. Background Tobacco use is the leading cause of preventable disease and death in Ontario, linked to approximately 13,000 avoidable premature deaths annually – the vast majority of these are attributable to cancer, cardiovascular disease, and chronic obstructive lung disease. (1) In Ontario, tobacco related health care costs amount to $6.1 billion annually, or about $502 per person (including non-smokers) and account for 1.4% of the provincial domestic product. (2) In 2007, there were approximately 1.7 to 1.9 million smokers in Ontario with two-thirds of these intending to quit in the next six months and one-third wanting to quit within 30 days. (3) In 2007/2008, Ontario invested $15 million in cessation programs, services and training. (4) In June 2009, the Ministry of Health Promotion (MHP) requested that MAS provide a summary of the evidence base surrounding population-based smoking cessation strategies. Project Scope The MAS and the MHP agreed that the project would consist of a clinical and economic summary of the evidence surrounding nine population-based strategies for smoking cessation including: Mass media interventions Telephone counselling Post-secondary smoking cessation programs (colleges/universities) Community-wide stop-smoking contests (i.e. Quit and Win) Community interventions Physician advice to quit Nursing interventions for smoking cessation Hospital-based interventions for smoking cessation Pharmacotherapies for smoking cessation, specifically: Nicotine replacement therapies Antidepressants Anxiolytic drugs Opioid antagonists Clonidine Nicotine receptor partial agonists Reviews examining interventions for Cut Down to Quit (CDTQ) or harm reduction were not included in this review. In addition

  18. Preindustrial to Present-Day Changes in Tropospheric Hydroxyl Radical and Methane Lifetime from the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP)

    NASA Technical Reports Server (NTRS)

    Naik, V.; Voulgarakis, A.; Fiore, A. M.; Horowitz, L. W.; Lamarque, J.-F.; Lin, M.; Prather, M. J.; Young, P. J.; Bergmann, D.; Cameron-Smith, P. J.; Cionni, I.; Collins, W. J.; Dalsoren, S. B.; Doherty, R.; Eyring, V.; Faluvegi, G.; Folberth, G. A.; Josse, B.; Lee, Y. H.; MacKenzie, I. A.; Nagashima, T.; vanNoije, T. P. C.; Plummer, D. A.; Righi, M.; Rumbold, S. T.; Skeie, R.; Shindell, D. T.; Stevenson, D. S.; Strode, S.; Sudo, K.; Szopa, S.; Zeng, G.

    2013-01-01

    We have analysed time-slice simulations from 17 global models, participating in the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP), to explore changes in present-day (2000) hydroxyl radical (OH) concentration and methane (CH4) lifetime relative to preindustrial times (1850) and to 1980. A comparison of modeled and observation-derived methane and methyl chloroform lifetimes suggests that the present-day global multi-model mean OH concentration is overestimated by 5 to 10% but is within the range of uncertainties. The models consistently simulate higher OH concentrations in the Northern Hemisphere (NH) compared with the Southern Hemisphere (SH) for the present-day (2000; inter-hemispheric ratios of 1.13 to 1.42), in contrast to observation-based approaches which generally indicate higher OH in the SH although uncertainties are large. Evaluation of simulated carbon monoxide (CO) concentrations, the primary sink for OH, against ground-based and satellite observations suggests low biases in the NH that may contribute to the high north–south OH asymmetry in the models. The models vary widely in their regional distribution of present-day OH concentrations (up to 34%). Despite large regional changes, the multi-model global mean (mass-weighted) OH concentration changes little over the past 150 yr, due to concurrent increases in factors that enhance OH (humidity, tropospheric ozone, nitrogen oxide (NOx) emissions, and UV radiation due to decreases in stratospheric ozone), compensated by increases in OH sinks (methane abundance, carbon monoxide and non-methane volatile organic carbon (NMVOC) emissions). The large inter-model diversity in the sign and magnitude of preindustrial to present-day OH changes (ranging from a decrease of 12.7% to an increase of 14.6%) indicate that uncertainty remains in our understanding of the long-term trends in OH and methane lifetime. We show that this diversity is largely explained by the different ratio of the

  19. Neutron Lifetime Measurements

    NASA Astrophysics Data System (ADS)

    Nico, J. S.

    2006-11-01

    Precision measurements of neutron beta decay address basic questions in nuclear and particle physics, astrophysics, and cosmology. As the simplest semileptonic decay system, the free neutron plays an important role in understanding the physics of the weak interaction, and improving the precision of the neutron lifetime is fundamental to testing the validity of the theory. The neutron lifetime also directly affects the relative abundance of primordial helium in big bang nucleosynthesis. There are two distinct strategies for measuring the lifetime. Experiments using cold neutrons measure the absolute specific activity of a beam of neutrons by counting decay protons; experiments using confined, ultracold neutrons determine the lifetime by counting neutrons that remain after some elapsed time. The status of the recent lifetime measurements using both of these techniques is discussed.

  20. Neutron Lifetime Measurements

    SciTech Connect

    Nico, J. S.

    2006-11-17

    Precision measurements of neutron beta decay address basic questions in nuclear and particle physics, astrophysics, and cosmology. As the simplest semileptonic decay system, the free neutron plays an important role in understanding the physics of the weak interaction, and improving the precision of the neutron lifetime is fundamental to testing the validity of the theory. The neutron lifetime also directly affects the relative abundance of primordial helium in big bang nucleosynthesis. There are two distinct strategies for measuring the lifetime. Experiments using cold neutrons measure the absolute specific activity of a beam of neutrons by counting decay protons; experiments using confined, ultracold neutrons determine the lifetime by counting neutrons that remain after some elapsed time. The status of the recent lifetime measurements using both of these techniques is discussed.

  1. On the reduced lifetime of nitrous oxide due to climate change induced acceleration of the Brewer-Dobson circulation as simulated by the MPI Earth System Model

    NASA Astrophysics Data System (ADS)

    Kracher, D.; Manzini, E.; Reick, C. H.; Schultz, M. G.; Stein, O.

    2014-12-01

    Greenhouse gas induced climate change will modify the physical conditions of the atmosphere. One of the projected changes is an acceleration of the Brewer-Dobson circulation in the stratosphere, as it has been shown in many model studies. This change in the stratospheric circulation consequently bears an effect on the transport and distribution of atmospheric components such as N2O. Since N2O is involved in ozone destruction, a modified distribution of N2O can be of importance for ozone chemistry. N2O is inert in the troposphere and decays only in the stratosphere. Thus, changes in the exchange between troposphere and stratosphere can also affect the stratospheric sink of N2O, and consequently its atmospheric lifetime. N2O is a potent greenhouse gas with a global warming potential of currently approximately 300 CO2-equivalents in a 100-year perspective. A faster decay in atmospheric N2O mixing ratios, i.e. a decreased atmospheric lifetime of N2O, will also reduce its global warming potential. In order to assess the impact of climate change on atmospheric circulation and implied effects on the distribution and lifetime of atmospheric N2O, we apply the Max Planck Institute Earth System Model, MPI-ESM. MPI-ESM consists of the atmospheric general circulation model ECHAM, the land surface model JSBACH, and MPIOM/HAMOCC representing ocean circulation and ocean biogeochemistry. Prognostic atmospheric N2O concentrations in MPI-ESM are determined by land N2O emissions, ocean-atmosphere N2O exchange and atmospheric tracer transport. As stratospheric chemistry is not explicitly represented in MPI-ESM, stratospheric decay rates of N2O are prescribed from a MACC MOZART simulation. Increasing surface temperatures and CO2 concentrations in the stratosphere impact atmospheric circulation differently. Thus, we conduct a series of transient runs with the atmospheric model of MPI-ESM to isolate different factors governing a shift in atmospheric circulation. From those transient

  2. Polymer damage mitigation---predictive lifetime models of polymer insulation degradation and biorenewable thermosets through cationic polymerization for self-healing applications

    NASA Astrophysics Data System (ADS)

    Hondred, Peter Raymond

    Over the past 50 years, the industrial development and applications for polymers and polymer composites has become expansive. However, as with any young technology, the techniques for predicting material damage and resolving material failure are in need of continued development and refinement. This thesis work takes two approaches to polymer damage mitigation---material lifetime prediction and spontaneous damage repair through self-healing while incorporating bio-renewable feedstock. First, material lifetime prediction offers the benefit of identifying and isolating material failures before the effects of damage results in catastrophic failure. Second, self-healing provides a systematic approach to repairing damaged polymer composites, specifically in applications where a hands-on approach or removing the part from service are not feasible. With regard to lifetime prediction, we investigated three specific polymeric materials---polytetrafluoroethylene (PTFE), poly(ethylene-alt-tetrafluoroethylene) (ETFE), and Kapton. All three have been utilized extensively in the aerospace field as a wire insulation coating. Because of the vast amount of electrical wiring used in aerospace constructions and the potential for electrical and thermal failure, this work develops mathematical models for both the thermal degradation kinetics as well as a lifetime prediction model for electrothermal breakdown. Isoconversional kinetic methods, which plot activation energy as a function of the extent of degradation, present insight into the development each kinetic model. The models for PTFE, ETFE, and Kapton are one step, consecutive three-step, and competitive and consecutive five-step respectively. Statistical analysis shows that an nth order autocatalytic reaction best defined the reaction kinetics for each polymer's degradation. Self-healing polymers arrest crack propagation through the use of an imbedded adhesive that reacts when cracks form. This form of damage mitigation focuses on

  3. Theoretical modeling of fiber laser at 810 nm based on thulium-doped silica fibers with enhanced 3H4 level lifetime.

    PubMed

    Peterka, Pavel; Kasik, Ivan; Dhar, Anirban; Dussardier, Bernard; Blanc, Wilfried

    2011-01-31

    A compact upconversion fiber laser operating around 810 nm is proposed using thulium-doped silica-based fiber with locally modified thulium environment by high alumina codoping. Using a comprehensive numerical model of thulium doped fiber we investigate performance of the proposed laser. Comparison with two other thulium hosts, fluoride glass and standard silica, is presented. Efficient lasing can be expected even for silica based fiber for specific ranges of the fiber and laser cavity parameters, especially when 3H4 lifetime is enhanced. With moderate pump power of 5 W at wavelength of 1064 nm, the predicted output power of the upconversion laser is about 2 W at 810 nm.

  4. Population-based study on infant mortality.

    PubMed

    Lima, Jaqueline Costa; Mingarelli, Alexandre Marchezoni; Segri, Neuber José; Zavala, Arturo Alejandro Zavala; Takano, Olga Akiko

    2017-03-01

    Although Brazil has reduced social, economic and health indicators disparities in the last decade, intra- and inter-regional differences in child mortality rates (CMR) persist in regions such as the state capital of Mato Grosso. This population-based study aimed to investigate factors associated with child mortality in five cohorts of live births (LB) of mothers living in Cuiabá (MT), Brazil, 2006-2010, through probabilistic linkage in 47,018 LB. We used hierarchical logistic regression analysis. Of the 617 child deaths, 48% occurred in the early neonatal period. CMR ranged from 14.6 to 12.0 deaths per thousand LB. The following remained independently associated with death: mothers without companion (OR = 1.32); low number of prenatal consultations (OR = 1.65); low birthweight (OR = 4.83); prematurity (OR = 3.05); Apgar ≤ 7 at the first minute (OR = 3.19); Apgar ≤ 7 at the fifth minute (OR = 4.95); congenital malformations (OR = 14.91) and male gender (OR = 1.26). CMR has declined in Cuiabá, however, there is need to guide public healthcare policies in the prenatal and perinatal period to reduce early neonatal mortality and further studies to identify the causes of preventable deaths.

  5. Stochastic Analysis of Orbital Lifetimes of Spacecraft

    NASA Technical Reports Server (NTRS)

    Sasamoto, Washito; Goodliff, Kandyce; Cornelius, David

    2008-01-01

    A document discusses (1) a Monte-Carlo-based methodology for probabilistic prediction and analysis of orbital lifetimes of spacecraft and (2) Orbital Lifetime Monte Carlo (OLMC)--a Fortran computer program, consisting of a previously developed long-term orbit-propagator integrated with a Monte Carlo engine. OLMC enables modeling of variances of key physical parameters that affect orbital lifetimes through the use of probability distributions. These parameters include altitude, speed, and flight-path angle at insertion into orbit; solar flux; and launch delays. The products of OLMC are predicted lifetimes (durations above specified minimum altitudes) for the number of user-specified cases. Histograms generated from such predictions can be used to determine the probabilities that spacecraft will satisfy lifetime requirements. The document discusses uncertainties that affect modeling of orbital lifetimes. Issues of repeatability, smoothness of distributions, and code run time are considered for the purpose of establishing values of code-specific parameters and number of Monte Carlo runs. Results from test cases are interpreted as demonstrating that solar-flux predictions are primary sources of variations in predicted lifetimes. Therefore, it is concluded, multiple sets of predictions should be utilized to fully characterize the lifetime range of a spacecraft.

  6. Stroboscopic fluorescence lifetime imaging.

    PubMed

    Holton, Mark D; Silvestre, Oscar R; Errington, Rachel J; Smith, Paul J; Matthews, Daniel R; Rees, Paul; Summers, Huw D

    2009-03-30

    We report a fluorescence lifetime imaging technique that uses the time integrated response to a periodic optical excitation, eliminating the need for time resolution in detection. A Dirac pulse train of variable period is used to probe the frequency response of the total fluorescence per pulse leading to a frequency roll-off that is dependent on the relaxation rate of the fluorophores. The technique is validated by demonstrating wide-field, realtime, lifetime imaging of the endocytosis of inorganic quantum dots by a cancer cell line. Surface charging of the dots in the intra-cellular environment produces a switch in the fluorescence lifetime from approximately 40 ns to < 10 ns. A temporal resolution of half the excitation period is possible which in this instance is 15 ns. This stroboscopic technique offers lifetime based imaging at video rates with standard CCD cameras and has application in probing millisecond cell dynamics and in high throughput imaging assays.

  7. Thermo-mechanical and neutron lifetime modeling and design of Be pebbles in the neutron multiplier for the LIFE engine

    SciTech Connect

    DeMange, P; Marian, J; de Caro, M S; Caro, A

    2009-03-16

    Concept designs for the laser-initiated fusion/fission engine (LIFE) include a neutron multiplication blanket containing Be pebbles flowing in a molten salt coolant. These pebbles must be designed to withstand the extreme irradiation and temperature conditions in the blanket to enable a safe and cost-effective operation of LIFE. In this work, we develop design criteria for spherical Be pebbles on the basis of their thermomechanical behavior under continued neutron exposure. We consider the effects of high fluence/fast flux on the elastic, thermal and mechanical properties of nuclear-grade Be. Our results suggest a maximum pebble diameter of 30 mm to avoid tensile failure, coated with an anti-corrosive, high-strength metallic shell to avoid failure by pebble contact. Moreover, we find that the operation temperature must always be kept above 450 C to enable creep to relax the stresses induced by swelling, which we estimate to be at least 16 months if uncoated and up to six years when coated. We identify the sources of uncertainty on the properties used and discuss the advantages of new intermetallic beryllides and their use in LIFE's neutron multiplier. To establish Be-pebble lifetimes with improved confidence, reliable experiments to measure irradiation creep must be performed.

  8. Variations on the Theme of Synaptic Filtering: A Comparison of Integrate-and-Express Models of Synaptic Plasticity for Memory Lifetimes.

    PubMed

    Elliott, Terry

    2016-09-14

    Integrate-and-express models of synaptic plasticity propose that synapses integrate plasticity induction signals before expressing synaptic plasticity. By discerning trends in their induction signals, synapses can control destabilizing fluctuations in synaptic strength. In a feedforward perceptron framework with binary-strength synapses for associative memory storage, we have previously shown that such a filter-based model outperforms other, nonintegrative, "cascade"-type models of memory storage in most regions of biologically relevant parameter space. Here, we consider some natural extensions of our earlier filter model, including one specifically tailored to binary-strength synapses and one that demands a fixed, consecutive number of same-type induction signals rather than merely an excess before expressing synaptic plasticity. With these extensions, we show that filter-based models outperform nonintegrative models in all regions of biologically relevant parameter space except for a small sliver in which all models encode memories only weakly. In this sliver, which model is superior depends on the metric used to gauge memory lifetimes (whether a signal-to-noise ratio or a mean first passage time). After comparing and contrasting these various filter models, we discuss the multiple mechanisms and timescales that underlie both synaptic plasticity and memory phenomena and suggest that multiple different filtering mechanisms may operate at single synapses.

  9. SO2 Emissions and Lifetimes: Estimates from Inverse Modeling Using In Situ and Global, Space-Based (SCIAMACHY and OMI) Observations

    NASA Technical Reports Server (NTRS)

    Lee, Chulkyu; Martin Randall V.; vanDonkelaar, Aaron; Lee, Hanlim; Dickerson, RUssell R.; Hains, Jennifer C.; Krotkov, Nickolay; Richter, Andreas; Vinnikov, Konstantine; Schwab, James J.

    2011-01-01

    Top-down constraints on global sulfur dioxide (SO2) emissions are inferred through inverse modeling using SO2 column observations from two satellite instruments (SCIAMACHY and OMI). We first evaluated the S02 column observations with surface SO2 measurements by applying local scaling factors from a global chemical transport model (GEOS-Chem) to SO2 columns retrieved from the satellite instruments. The resulting annual mean surface SO2 mixing ratios for 2006 exhibit a significant spatial correlation (r=0.86, slope=0.91 for SCIAMACHY and r=0.80, slope = 0.79 for OMI) with coincident in situ measurements from monitoring networks throughout the United States and Canada. We evaluate the GEOS-Chem simulation of the SO2 lifetime with that inferred from in situ measurements to verity the applicability of GEOS-Chem for inversion of SO2 columns to emissions. The seasonal mean SO2 lifetime calculated with the GEOS-Chem model over the eastern United States is 13 h in summer and 48 h in winter, compared to lifetimes inferred from in situ measurements of 19 +/- 7 h in summer and 58 +/- 20 h in winter. We apply SO2 columns from SCIAMACHY and OMI to derive a top-down anthropogenic SO2 emission inventory over land by using the local GEOS-Chem relationship between SO2 columns and emissions. There is little seasonal variation in the top-down emissions (<15%) over most major industrial regions providing some confidence in the method. Our global estimate for annual land surface anthropogenic SO2 emissions (52.4 Tg S/yr from SCIAMACHY and 49.9 Tg S / yr from OMI) closely agrees with the bottom-up emissions (54.6 Tg S/yr) in the GEOS-Chem model and exhibits consistency in global distributions with the bottom-up emissions (r = 0.78 for SCIAMACHY, and r = 0.77 for OMI). However, there are significant regional differences.

  10. Incidence and Mortality of Obstructive Lung Disease in Rheumatoid Arthritis: A Population-Based Study

    PubMed Central

    Nannini, Carlotta; Medina-Velasquez, Yimy F.; Achenbach, Sara J.; Crowson, Cynthia S.; Ryu, Jay H.; Vassallo, Robert; Gabriel, Sherine E.; Matteson, Eric L.; Bongartz, Tim

    2014-01-01

    OBJECTIVE Pulmonary disease represents an important extra-articular manifestation of rheumatoid arthritis (RA). While the association of RA and interstitial lung disease is widely acknowledged, obstructive lung disease (OLD) in RA is less well understood. We therefore aimed to assess incidence, risk factors and mortality of OLD in patients with RA. METHODS We examined a population-based incident cohort of patients with RA and a comparison cohort of individuals without RA. OLD was defined using a strict composite criterion. Cox-proportional hazards models were used to compare OLD incidence between the RA and comparator cohort, to investigate risk factors and to explore the impact of OLD on patient survival. RESULTS 594 patients with RA and 596 subjects without RA were followed for a mean of 16.3 and 19.4 years, respectively. The lifetime risk of developing OLD was 9.6% for RA patients and 6.2% for subjects without RA; hazard ratio (HR) 1.54 (95% CI 1.01 to 2.34). The risk of developing OLD was higher among male patients, current or former smokers and for individuals with more severe RA. Survival of RA patients diagnosed with OLD was worse compared to those without OLD (HR 2.09, 95% CI 1.47 to 2.97). CONCLUSION Patients with RA are at higher risk of developing OLD, which is significantly associated with premature mortality. Effective diagnostic and therapeutic strategies to detect and manage OLD in patients with RA may help to improve survivorship in these patients. PMID:23436637

  11. Cross-sectional study of HPV-16 infection in a population-based subsample of Hispanic adults

    PubMed Central

    Ortiz, A P; Unger, E R; Muñoz, C; Panicker, G; Tortolero-Luna, G; Soto-Salgado, M; Otero, Y; Suárez, E; Pérez, C M

    2014-01-01

    Objective This study aimed to estimate the prevalence and correlates of seropositivity to human papillomavirus (HPV)-16 in a subsample of adults who participated in the parent study Epidemiology of Hepatitis C in the adult population of Puerto Rico (PR). Setting The parent study was a population-based household survey aimed to estimate the seroprevalence of hepatitis C and other viral infections (hepatitis A, hepatitis B, HIV, and herpes simplex type 2) in PR (n=1654) between 2005 and 2008. Participants A subsample of the last 450 consecutive adults aged 21–64 years, recruited between February 2007 and January 2008, who participated in the parent study and agreed to participate in HPV testing. Primary and secondary outcome measures The samples were tested by ELISA for HPV-16 viral-like particle-specific immunoglobulin G. Information on sociodemographic, health, and lifestyle characteristics was collected. Logistic regression modelling was used to estimate the prevalence odds ratio (POR) to assess factors associated to HPV-16 seropositivity. Results Prevalence of seropositivity to HPV-16 was 11.3%. Seroprevalence was higher in women (15.8%) than men (5.6%; p=0.001). After adjusting for age and sex, ever smokers (POR 2.06, 95% CI 1.08 to 3.92) and participants with at least five lifetime sexual partners (POR 2.91, 95% CI 1.24 to 6.81) were more likely to be HPV-16 seropositive. Conclusions HPV-16 seropositivity is similar to that reported in the USA (10.4%) for NHANES 2003–2004 participants, although different assays were used in these studies. While future studies should evaluate HPV seroprevalence using a larger population-based sample, our results highlight the need to further understand the burden of HPV infection and HPV-related malignancies in PR, population with a low vaccine uptake. PMID:24496698

  12. Fluorescence lifetime attachment LIFA

    NASA Astrophysics Data System (ADS)

    van der Oord, Cornelius J. R.; Stoop, Karel W. J.; van Geest, Lambertus K.

    2001-05-01

    We present the Lambert Instruments Fluorescence Lifetime Attachment LIFA. LIFA enables easy to use and affordable microscopy and macroscopic FLIM. The system implements the homodyne detection scheme for measuring the fluorescence lifetime in each pixel of the image. The microscopy system features an ultra bright LED illuminator, the LI-(mu) Cam intensified CCD camera a high frequency signal generator. The illuminator replaces the excitation light source of a standard fluorescence microscopy, while the LI-(mu) CAM intensified CCD camera is attached to the photo-port. Both the illuminator and the intensifier are modulated at a frequency up to 100 MHz at a series of phase differences. The lifetime image is calculated from the series of images on a personal computer.

  13. Subdural haemorrhages in infants: population based study

    PubMed Central

    Jayawant, S; Rawlinson, A; Gibbon, F; Price, J; Schulte, J; Sharples, P; Sibert, J R; Kemp, A M

    1998-01-01

    Objectives To identify the incidence, clinical outcome, and associated factors of subdural haemorrhage in children under 2 years of age, and to determine how such cases were investigated and how many were due to child abuse. Design Population based case series. Setting South Wales and south west England. Subjects Children under 2 years of age who had a subdural haemorrhage. We excluded neonates who developed subdural haemorrhage during their stay on a neonatal unit and infants who developed a subdural haemorrhage after infection or neurosurgical intervention. Main outcome measures Incidence and clinical outcome of subdural haemorrhage in infants, the number of cases caused by child abuse, the investigations such children received, and associated risk factors. Results Thirty three children (23 boys and 10 girls) were identified with subdural haemorrhage. The incidence was 12.8/100 000 children/year (95% confidence interval 5.4 to 20.2). Twenty eight cases (85%) were under 1 year of age. The incidence of subdural haemorrhage in children under 1 year of age was 21.0/100 000 children/year and was therefore higher than in the older children. The clinical outcome was poor: nine infants died and 15 had profound disability. Only 22 infants had the basic investigations of a full blood count, coagulation screen, computed tomography or magnetic resonance imaging, skeletal survey or bone scan, and ophthalmological examination. In retrospect, 27 cases (82%) were highly suggestive of abuse. Conclusion Subdural haemorrhage is common in infancy and carries a poor prognosis; three quarters of such infants die or have profound disability. Most cases are due to child abuse, but in a few the cause is unknown. Some children with subdural haemorrhage do not undergo appropriate investigations. We believe the clinical investigation of such children should include a full multidisciplinary social assessment, an ophthalmic examination, a skeletal survey supplemented with a bone scan or a

  14. Lifetimes and configuration mixing in 110Cd

    NASA Astrophysics Data System (ADS)

    Lobach, Yu. N.; Efimov, A. D.; Pasternak, A. A.

    Lifetimes of excited states in 110Cd have been measured by the Doppler shift attenuation method in the reaction (α,2nγ) at Eα= 25 MeV. Lifetime values for 8 states and lifetime limits for 3 states were obtained. The band structures of 110Cd have been interpreted in terms of a modified version of the interacting boson model (IBM + 2 q.p.). The calculations explain well the excitation energies and electromagnetic transition probabilities up to Jπ= 16+, except for the 10+1 state. The structural features are discussed in terms of collective and two quasiparticle excitations.

  15. Parenting and risk for mood, anxiety and substance use disorders: a study in population-based male twins

    PubMed Central

    Gardner, Charles O.; Kendler, Kenneth S.; Hettema, John M.

    2013-01-01

    Background Previous studies consistently identified a relationship between parenting behavior and psychopathology. In this study, we extended prior analyses performed in female twins to a large sample of twins from male–male pairs. Methods We used interview data on 2,609 adult male twins from a population-based twin registry. We examined the association between three retrospectively reported parenting dimensions (coldness, protectiveness, and authoritarianism) and lifetime history of seven common psychiatric and substance use disorders. Using univariate structural equation modeling, we also examined the influence of the genetic and environmental factors on parenting. Results Examined individually, coldness was consistently associated with risk for a broad range of adult psychopathology. Averaged odds of psychiatric disorders associated with parenting were increased between 26 and 36 %. When the three parenting dimensions were examined together, coldness remained significant for major depression, phobia, and generalized anxiety disorder. Controlling for other disorders, the associations between the parenting dimensions and psychopathology were non-specific. Twin fitting model demonstrated that modest heritability accounted for parenting, whereas most variance resulted from the non-shared environment. Conclusions Based on our current and prior findings, there is broad similarity in the impact of parenting on adult psychopathology between men and women. PMID:23344783

  16. Cycle ageing analysis of a LiFePO4/graphite cell with dynamic model validations: Towards realistic lifetime predictions

    NASA Astrophysics Data System (ADS)

    Sarasketa-Zabala, E.; Gandiaga, I.; Martinez-Laserna, E.; Rodriguez-Martinez, L. M.; Villarreal, I.

    2015-02-01

    The present investigation work compares cycling ageing behaviour upon constant operation conditions (static tests) with degradation under non-constant schemes (dynamic tests), through a novel methodology for ageing model dynamic validation. A LFP-based Li-ion cell performance loss is analysed using a DOD and C-rate stress factors Ah-throughput-domain characterisation method, and represented using a semi-empirical model. The proposed stepwise validation approach enables assessing the static ageing tests acceleration factor and systematically improving the ageing model. The result is a simple but comprehensive model. The predictions root-mean-square error, under dynamic cycling operation conditions, is just 1.75%.

  17. Our Allotted Lifetimes

    ERIC Educational Resources Information Center

    Gould, Stephen Jay

    1977-01-01

    It is suggested that measured by the internal clock of heartbeats or breathing, all mammals live a similar lifespan. This is based on the fact that mammals, regardless of size, breathe about 200 million times in their lifetime at a rate of 1 breath for every 4 heartbeats. (AJ)

  18. Do quasars have cosmologically long lifetimes

    NASA Technical Reports Server (NTRS)

    Chanan, G. A.

    1982-01-01

    An alternative explanation to gravitational lensing is examined, by which problems inherent in space density evolution are avoided without invoking gravitational effects. Apparent and unreal density evolution follows as an immediate consequence, if the quasar lifetimes that are the only free parameter in the model proposed are of the order of three billion years. If such lifetimes are the case, while quasars may occur less frequently than has been thought, the local density of quasars may have been grossly underestimated.

  19. Lifetime assessment by intermittent inspection under the mixture Weibull power law model with application to XLPE cables.

    PubMed

    Hirose, H

    1997-01-01

    This paper proposes a new treatment for electrical insulation degradation. Some types of insulation which have been used under various circumstances are considered to degrade at various rates in accordance with their stress circumstances. The cross-linked polyethylene (XLPE) insulated cables inspected by major Japanese electric companies clearly indicate such phenomena. By assuming that the inspected specimen is sampled from one of the clustered groups, a mixed degradation model can be constructed. Since the degradation of the insulation under common circumstances is considered to follow a Weibull distribution, a mixture model and a Weibull power law can be combined. This is called The mixture Weibull power law model. By using the maximum likelihood estimation for the newly proposed model to Japanese 22 and 33 kV insulation class cables, they are clustered into a certain number of groups by using the AIC and the generalized likelihood ratio test method. The reliability of the cables at specified years are assessed.

  20. The atmospheric lifetime of black carbon

    NASA Astrophysics Data System (ADS)

    Cape, J. N.; Coyle, M.; Dumitrean, P.

    2012-11-01

    Black carbon (BC) in the atmosphere contributes to the human health effects of particulate matter and contributes to radiative forcing of climate. The lifetime of BC, particularly the smaller particle sizes (PM2.5) which can be transported over long distances, is therefore an important factor in determining the range of such effects, and the spatial footprint of emission controls. Theory and models suggest that the typical lifetime of BC is around one week. The frequency distributions of measurements of a range of hydrocarbons at a remote rural site in southern Scotland (Auchencorth Moss) between 2007 and 2010 have been used to quantify the relationship between atmospheric lifetime and the geometric standard deviation of observed concentration. The analysis relies on an assumed common major emission source for hydrocarbons and BC, namely diesel-engined vehicles. The logarithm of the standard deviation of the log-transformed concentration data is linearly related to hydrocarbon lifetime, and the same statistic for BC can be used to assess the lifetime of BC relative to the hydrocarbons. Annual average data show BC lifetimes in the range 4-12 days, for an assumed OH concentration of 7 × 105 cm-3. At this site there is little difference in BC lifetime between winter and summer, despite a 3-fold difference in relative hydrocarbon lifetimes. This observation confirms the role of wet deposition as an important removal process for BC, as there is no difference in precipitation between winter and summer at this site. BC lifetime was significantly greater in 2010, which had 23% less rainfall than the preceding 3 years.

  1. The simcyp population based simulator: architecture, implementation, and quality assurance.

    PubMed

    Jamei, Masoud; Marciniak, Steve; Edwards, Duncan; Wragg, Kris; Feng, Kairui; Barnett, Adrian; Rostami-Hodjegan, Amin

    2013-01-01

    Developing a user-friendly platform that can handle a vast number of complex physiologically based pharmacokinetic and pharmacodynamic (PBPK/PD) models both for conventional small molecules and larger biologic drugs is a substantial challenge. Over the last decade the Simcyp Population Based Simulator has gained popularity in major pharmaceutical companies (70% of top 40 - in term of R&D spending). Under the Simcyp Consortium guidance, it has evolved from a simple drug-drug interaction tool to a sophisticated and comprehensive Model Based Drug Development (MBDD) platform that covers a broad range of applications spanning from early drug discovery to late drug development. This article provides an update on the latest architectural and implementation developments within the Simulator. Interconnection between peripheral modules, the dynamic model building process and compound and population data handling are all described. The Simcyp Data Management (SDM) system, which contains the system and drug databases, can help with implementing quality standards by seamless integration and tracking of any changes. This also helps with internal approval procedures, validation and auto-testing of the new implemented models and algorithms, an area of high interest to regulatory bodies.

  2. Implementation of Remaining Useful Lifetime Transformer Models in the Fleet-Wide Prognostic and Health Management Suite

    SciTech Connect

    Agarwal, Vivek; Lybeck, Nancy J.; Pham, Binh; Rusaw, Richard; Bickford, Randall

    2015-02-01

    Research and development efforts are required to address aging and reliability concerns of the existing fleet of nuclear power plants. As most plants continue to operate beyond the license life (i.e., towards 60 or 80 years), plant components are more likely to incur age-related degradation mechanisms. To assess and manage the health of aging plant assets across the nuclear industry, the Electric Power Research Institute has developed a web-based Fleet-Wide Prognostic and Health Management (FW-PHM) Suite for diagnosis and prognosis. FW-PHM is a set of web-based diagnostic and prognostic tools and databases, comprised of the Diagnostic Advisor, the Asset Fault Signature Database, the Remaining Useful Life Advisor, and the Remaining Useful Life Database, that serves as an integrated health monitoring architecture. The main focus of this paper is the implementation of prognostic models for generator step-up transformers in the FW-PHM Suite. One prognostic model discussed is based on the functional relationship between degree of polymerization, (the most commonly used metrics to assess the health of the winding insulation in a transformer) and furfural concentration in the insulating oil. The other model is based on thermal-induced degradation of the transformer insulation. By utilizing transformer loading information, established thermal models are used to estimate the hot spot temperature inside the transformer winding. Both models are implemented in the Remaining Useful Life Database of the FW-PHM Suite. The Remaining Useful Life Advisor utilizes the implemented prognostic models to estimate the remaining useful life of the paper winding insulation in the transformer based on actual oil testing and operational data.

  3. Adult Prevalence of Epilepsy in Spain: EPIBERIA, a Population-Based Study

    PubMed Central

    Serrano-Castro, Pedro J.; Mauri-Llerda, Jose Angel; Hernández-Ramos, Francisco José; Sánchez-Alvarez, Juan Carlos; Parejo-Carbonell, Beatriz; Quiroga-Subirana, Pablo; Vázquez-Gutierrez, Fernando; Santos-Lasaosa, Sonia; Mendez-Lucena, Carolina; Redondo-Verge, Luis; Tejero-Juste, Carlos; Morandeira-Rivas, Clara; Sancho-Rieger, Jerónimo; Matías-Guiu, Jorge

    2015-01-01

    Background. This study assesses the lifetime and active prevalence of epilepsy in Spain in people older than 18 years. Methods. EPIBERIA is a population-based epidemiological study of epilepsy prevalence using data from three representative Spanish regions (health districts in Zaragoza, Almería, and Seville) between 2012 and 2013. The study consisted of two phases: screening and confirmation. Participants completed a previously validated questionnaire (EPIBERIA questionnaire) over the telephone. Results. A total of 1741 valid questionnaires were obtained, including 261 (14.99%) raising a suspicion of epilepsy. Of these suspected cases, 216 (82.75%) agreed to participate in phase 2. Of the phase 2 participants, 22 met the International League Against Epilepsy's diagnostic criteria for epilepsy. The estimated lifetime prevalence, adjusted by age and sex per 1,000 people, was 14.87 (95% CI: 9.8–21.9). Active prevalence was 5.79 (95% CI: 2.8–10.6). No significant age, sex, or regional differences in prevalence were detected. Conclusions. EPIBERIA provides the most accurate estimate of epilepsy prevalence in the Mediterranean region based on its original methodology and its adherence to ILAE recommendations. We highlight that the lifetime prevalence and inactive epilepsy prevalence figures observed here were compared to other epidemiological studies. PMID:26783554

  4. History of depression and risk of hyperemesis gravidarum: a population-based cohort study.

    PubMed

    Kjeldgaard, Helena Kames; Eberhard-Gran, Malin; Benth, Jūratė Šaltytė; Nordeng, Hedvig; Vikanes, Åse Vigdis

    2017-01-07

    Hyperemesis gravidarum (HG) is a pregnancy condition characterised by debilitating nausea and vomiting. HG has been associated with depression during pregnancy but the direction of the association remains unclear. The aim of this study was to assess whether previous depression is associated with HG. This is a population-based pregnancy cohort study using data from The Norwegian Mother and Child Cohort Study. The study reviewed 731 pregnancies with HG and 81,055 pregnancies without. Logistic regression analyses were performed to examine the association between a lifetime history of depression and hyperemesis gravidarum. Odds ratios were adjusted for symptoms of current depression, maternal age, parity, body mass index, smoking, sex of the child, education and pelvic girdle pain. A lifetime history of depression was associated with higher odds for hyperemesis gravidarum (aOR = 1.49, 95% CI (1.23; 1.79)). Two thirds of women with hyperemesis gravidarum had neither a history of depression nor symptoms of current depression, and 1.2% of women with a history of depression developed HG. A lifetime history of depression increased the risk of HG. However, given the fact that only 1.2% of women with a history of depression developed HG and that the majority of women with HG had no symptoms of depression, depression does not seem to be a main driver in the aetiology of HG.

  5. Prevalence of exposure to suicide: A meta-analysis of population-based studies.

    PubMed

    Andriessen, Karl; Rahman, Bayzidur; Draper, Brian; Dudley, Michael; Mitchell, Philip B

    2017-05-01

    Those exposed to suicide are at increased risk of adverse outcomes including mental illness, impaired social functioning, and fatal and non-fatal suicidal behavior. However, it is unclear how many people are exposed to suicide in the general community. This first meta-analysis of population-based studies aimed to provide pooled estimates of past-year and lifetime prevalence of exposure to suicide among family, friends/peers, and all relationships. In addition, the study examined prevalence of exposure to suicide by age group: adolescents and adults. Systematic searches of the literature in Embase, Medline and PsycINFO identified eighteen studies that were included in the analysis. Pooled past-year prevalence was 4.31% (CI: 2.50 to 6.58) and life-time prevalence 21.83% (CI: 16.32 to 27.90). Both past-year and lifetime prevalences of exposure to suicide among friends and peers were significantly higher than the prevalence of exposure within families; there were no differences in the prevalence of exposure to suicide between adolescents and adults. Heterogeneity was highly significant. Future research should be conducted with large national representative samples and use standardised assessment instruments. Given the increased risks of adverse outcomes among those exposed to suicide, the high rate of exposure to suicide reported here has important ramifications for public health and mental health service delivery.

  6. Measurement of Beam Lifetime and Applications for SPEAR3

    SciTech Connect

    Huang, Xiaobiao; Corbett, Jeff; /SLAC

    2011-04-05

    Beam lifetime studies for the SPEAR3 storage ring are presented. The three lifetime components are separated with lifetime measurements under various combinations of beam currents and fill patterns and vertical scraper scans. Touschek lifetime is studied with rf voltage scans and with the horizontal or vertical scrapers inserted. The measurements are explained with calculations based on the calibrated lattice model. Quantum lifetime measurements are performed with reduced longitudinal and horizontal apertures, respectively, from which we deduce the radiation energy loss down to a few keV per revolution and the horizontal beam size.

  7. The ethical dilemma of population-based medical decision making.

    PubMed

    Kirsner, R S; Federman, D G

    1998-11-01

    Over the past several years, there has been a growing interest in population-based medicine. Some elements in healthcare have used population-based medicine as a technique to decrease healthcare expenditures. However, in their daily practice of medicine, physicians must grapple with the question of whether they incorporate population-based medicine when making decisions for an individual patient. They therefore may encounter an ethical dilemma. Physicians must remember that the physician-patient relationship is of paramount importance and that even well-conducted research may not be applicable to an individual patient.

  8. Discriminating famous from fictional names based on lifetime experience: evidence in support of a signal-detection model based on finite mixture distributions.

    PubMed

    Bowles, Ben; Harlow, Iain M; Meeking, Melissa M; Köhler, Stefan

    2012-01-01

    It is widely accepted that signal-detection mechanisms contribute to item-recognition memory decisions that involve discriminations between targets and lures based on a controlled laboratory study episode. Here, the authors employed mathematical modeling of receiver operating characteristics (ROC) to determine whether and how a signal-detection mechanism contributes to discriminations between moderately famous and fictional names based on lifetime experience. Unique to fame judgments is a lack of control over participants' previous exposure to the stimuli deemed "targets" by the experimenter; specifically, if they pertain to moderately famous individuals, participants may have had no prior exposure to a substantial proportion of the famous names presented. The authors adopted established models from the recognition-memory literature to examine the quantitative fit that could be obtained through the inclusion of signal-detection and threshold mechanisms for two data sets. They first established that a signal-detection process operating on graded evidence is critical to account for the fame judgment data they collected. They then determined whether the graded memory evidence for famous names would best be described with one distribution with greater variance than that for the fictional names, or with two finite mixture distributions for famous names that correspond to items with or without prior exposure, respectively. Analyses revealed that a model that included a d' parameter, as well as a mixture parameter, provided the best compromise between number of parameters and quantitative fit. Additional comparisons between this equal-variance signal-detection mixture model and a dual-process model, which included a high-threshold process in addition to a signal-detection process, also favored the former model. In support of the conjecture that the mixture parameter captures participants' prior experience, the authors found that it was increased when the analysis was

  9. Maximizing TDRS Command Load Lifetime

    NASA Technical Reports Server (NTRS)

    Brown, Aaron J.

    2002-01-01

    The GNC software onboard ISS utilizes TORS command loads, and a simplistic model of TORS orbital motion to generate onboard TORS state vectors. Each TORS command load contains five "invariant" orbital elements which serve as inputs to the onboard propagation algorithm. These elements include semi-major axis, inclination, time of last ascending node crossing, right ascension of ascending node, and mean motion. Running parallel to the onboard software is the TORS Command Builder Tool application, located in the JSC Mission Control Center. The TORS Command Builder Tool is responsible for building the TORS command loads using a ground TORS state vector, mirroring the onboard propagation algorithm, and assessing the fidelity of current TORS command loads onboard ISS. The tool works by extracting a ground state vector at a given time from a current TORS ephemeris, and then calculating the corresponding "onboard" TORS state vector at the same time using the current onboard TORS command load. The tool then performs a comparison between these two vectors and displays the relative differences in the command builder tool GUI. If the RSS position difference between these two vectors exceeds the tolerable lim its, a new command load is built using the ground state vector and uplinked to ISS. A command load's lifetime is therefore defined as the time from when a command load is built to the time the RSS position difference exceeds the tolerable limit. From the outset of TORS command load operations (STS-98), command load lifetime was limited to approximately one week due to the simplicity of both the onboard propagation algorithm, and the algorithm used by the command builder tool to generate the invariant orbital elements. It was soon desired to extend command load lifetime in order to minimize potential risk due to frequent ISS commanding. Initial studies indicated that command load lifetime was most sensitive to changes in mean motion. Finding a suitable value for mean motion

  10. Global three-dimensional model calculations of the budgets and present-day atmospheric lifetimes of CF2ClCFCl2 (CFC-113) and CHClF2 (CFC-22)

    NASA Technical Reports Server (NTRS)

    Golombek, Amram; Prinn, Ronald G.

    1989-01-01

    The annual percentage increases in concentrations of the chlorofluorocarbons CFC-113 (an industrial solvent) and CFC-22 (a refrigerant) are the highest among major chlorofluorocarbons in the atmosphere today. The present-day atmospheric lifetimes for these species are computed using a global three-dimensional dynamical-chemical model. The present-day lifetimes of both are long (15.5 years for CFC-22 and 136 or 195 years for CFC-113, depending on assumed O2 absorption cross sections), underscoring the need to decrease their emissions in order to minimize their future role in ozone destruction and greenhouse warming.

  11. Measurements of heavy quark and lepton lifetimes

    SciTech Connect

    Jaros, J.A.

    1985-02-01

    The PEP/PETRA energy range has proved to be well-suited for the study of the lifetimes of hadrons containing the b and c quarks and the tau lepton for several reasons. First, these states comprise a large fraction of the total interaction rate in e/sup +/e/sup -/ annihilation and can be cleanly identified. Second, the storage rings have operated at high luminosity and so produced these exotic states copiously. And finally, thanks to the interplay of the Fermi coupling strength, the quark and lepton masses, and the beam energy, the expected decay lengths are in the 1/2 mm range and so are comparatively easy to measure. This pleasant coincidence of cleanly identified and abundant signal with potentially large effects has made possible the first measurements of two fundamental weak couplings, tau ..-->.. nu/sub tau/W and b ..-->.. cW. These measurements have provided a sharp test of the standard model and allowed, for the first time, the full determination of the magnitudes of the quark mixing matrix. This paper reviews the lifetime studies made at PEP during the past year. It begins with a brief review of the three detectors, DELCO, MAC and MARK II, which have reported lifetime measurements. Next it discusses two new measurements of the tau lifetime, and briefly reviews a measurement of the D/sup 0/ lifetime. Finally, it turns to measurements of the B lifetime, which are discussed in some detail. 18 references, 14 figures, 1 table.

  12. Damage Mechanics Approach for Bearing Lifetime Prognostics

    NASA Astrophysics Data System (ADS)

    Qiu, Jing; Seth, Brij B.; Liang, Steven Y.; Zhang, Cheng

    2002-09-01

    The ability to achieve accurate bearing prognostics is critical to the optimal maintenance of rotating machinery in the interest of cost and productivity. However, techniques to real time predict the lifetime of a bearing under practical operating conditions have not been well developed. In this paper, a stiffness-based prognostic model for bearing systems based on vibration response analysis and damage mechanics is discussed. As the bearing system is considered as a single-degree-of-freedom vibratory system, its natural frequency and its acceleration amplitude at the natural frequency can be related to the system stiffness. On the other hand, the relationship between failure lifetime, running time and stiffness variation can be established from the damage mechanics. Combining the above two, the natural frequency and the acceleration amplitude of a bearing system can be related to its running time and failure lifetime. Thus, the failure lifetime of a bearing system can be predicted on-line based on vibration measurement. Experiments have been performed on a tapered roller bearing life testing stand under various operation conditions to calibrate and to validate the proposed model. The comparison between model-calculated data and experimental results indicates that this model can be used to effectively predict the failure lifetime and the remaining life of a bearing system.

  13. A Population-based Habitable Zone Perspective

    NASA Astrophysics Data System (ADS)

    Zsom, Andras

    2015-11-01

    What can we tell about exoplanet habitability if currently only the stellar properties, planet radius, and the incoming stellar flux are known? A planet is in the habitable zone (HZ) if it harbors liquid water on its surface. The HZ is traditionally conceived as a sharp region around stars because it is calculated for one planet with specific properties. Such an approach is limiting because the planet’s atmospheric and geophysical properties, which influence the presence of liquid water on the surface, are currently unknown but expected to be diverse. A statistical HZ description is outlined that does not favor one planet type. Instead, the stellar and planet properties are treated as random variables, and a continuous range of planet scenarios is considered. Various probability density functions are assigned to each random variable, and a combination of Monte Carlo sampling and climate modeling is used to generate synthetic exoplanet populations with known surface climates. Then, the properties of the subpopulation bearing liquid water is analyzed. Given our current observational knowledge, the HZ takes the form of a weakly constrained but smooth probability function. The HZ has an inner edge, but a clear outer edge is not seen. Currently only optimistic upper limits can be derived for the potentially observable HZ occurrence rate. Finally, we illustrate through an example how future data on exoplanet atmospheres will help to narrow down the probability that an exoplanet harbors liquid water, and we identify the greatest observational challenge in the way of finding a habitable exoplanet.

  14. Development of a new risk model for predicting cardiovascular events among hemodialysis patients: Population-based hemodialysis patients from the Japan Dialysis Outcome and Practice Patterns Study (J-DOPPS)

    PubMed Central

    Onishi, Yoshihiro; Fukuhara, Shunichi

    2017-01-01

    Background Cardiovascular (CV) events are the primary cause of death and becoming bedridden among hemodialysis (HD) patients. The Framingham risk score (FRS) is useful for predicting incidence of CV events in the general population, but is considerd to be unsuitable for the prediction of the incidence of CV events in HD patients, given their characteristics due to atypical relationships between conventional risk factors and outcomes. We therefore aimed to develop a new prognostic prediction model for prevention and early detection of CV events among hemodialysis patients. Methods We enrolled 3,601 maintenance HD patients based on their data from the Japan Dialysis Outcomes and Practice Patterns Study (J-DOPPS), phases 3 and 4. We longitudinaly assessed the association between several potential candidate predictors and composite CV events in the year after study initiation. Potential candidate predictors included the component factors of FRS and other HD-specific risk factors. We used multivariable logistic regression with backward stepwise selection to develop our new prediction model and generated a calibration plot. Additinially, we performed bootstrapping to assess the internal validity. Results We observed 328 composite CV events during 1-year follow-up. The final prediction model contained six variables: age, diabetes status, history of CV events, dialysis time per session, and serum phosphorus and albumin levels. The new model showed significantly better discrimination than the FRS, in both men (c-statistics: 0.76 for new model, 0.64 for FRS) and women (c-statistics: 0.77 for new model, 0.60 for FRS). Additionally, we confirmed the consistency between the observed results and predicted results using the calibration plot. Further, we found similar discrimination and calibration to the derivation model in the bootstrapping cohort. Conclusions We developed a new risk model consisting of only six predictors. Our new model predicted CV events more accurately than

  15. Dependence of the charge exchange lifetimes on mirror latitude

    NASA Technical Reports Server (NTRS)

    Smith, P. H.; Bewtra, N. K.

    1976-01-01

    The dependence of the charge exchange lifetimes on the mirror latitude for ions mirroring off the geomagnetic equator was re-computed using the improved hydrogen distribution models. The Chamberlain model was used to define the spatial distribution of the neutral hydrogen environment through which the ring current ions traverse. The resultant dependence of the charge exchange lifetime on mirror latitude is best fitted by the approximation that contains the charge exchange lifetime for equatorial particles.

  16. B Lifetimes and Mixing

    SciTech Connect

    Evans, Harold G.; /Indiana U.

    2009-05-01

    The Tevatron experiments, CDF and D0, have produced a wealth of new B-physics results since the start of Run II in 2001. We've observed new B-hadrons, seen new effects, and increased many-fold the precision with which we know the properties of b-quark systems. In these proceedings, we will discuss two of the most fruitful areas in the Tevatron B-physics program: lifetimes and mixing. We'll examine the experimental issues driving these analyses, present a summary of the latest results, and discuss prospects for the future.

  17. Dopant Cylinder Lifetime Monitor

    NASA Astrophysics Data System (ADS)

    Bishop, Steve; Wodjenski, Michael; Kaim, Robert; Lurcott, Steve; McManus, Jim; Smith, Gordon

    2006-11-01

    The cost of consumable materials is a significant component in the cost of implanter operation. With the higher cost of sub-atmospheric gas alternatives it is increasingly important to accurately monitor its usage. The ATMI® SDS® GasGauge™ monitoring system accurately monitors gas level in four cylinders simultaneously, throughout their lifetime, in order to optimize usage of gas and related implanter productivity. This paper displays how the GasGauge monitoring system accurately monitors the cylinder contents in SDS®, VAC® and high pressure gas cylinders. Internal and customer test data is also presented to verify these claims.

  18. A satellite mortality study to support space systems lifetime prediction

    NASA Astrophysics Data System (ADS)

    Fox, George; Salazar, Ronald; Habib-Agahi, Hamid; Dubos, Gregory F.

    Estimating the operational lifetime of satellites and spacecraft is a complex process. Operational lifetime can differ from mission design lifetime for a variety of reasons. Unexpected mortality can occur due to human errors in design and fabrication, to human errors in launch and operations, to random anomalies of hardware and software or even satellite function degradation or technology change, leading to unrealized economic or mission return. This study focuses on data collection of public information using, for the first time, a large, publically available dataset, and preliminary analysis of satellite lifetimes, both operational lifetime and design lifetime. The objective of this study is the illustration of the relationship of design life to actual lifetime for some representative classes of satellites and spacecraft. First, a Weibull and Exponential lifetime analysis comparison is performed on the ratio of mission operating lifetime to design life, accounting for terminated and ongoing missions. Next a Kaplan-Meier survivor function, standard practice for clinical trials analysis, is estimated from operating lifetime. Bootstrap resampling is used to provide uncertainty estimates of selected survival probabilities. This study highlights the need for more detailed databases and engineering reliability models of satellite lifetime that include satellite systems and subsystems, operations procedures and environmental characteristics to support the design of complex, multi-generation, long-lived space systems in Earth orbit.

  19. A Satellite Mortality Study to Support Space Systems Lifetime Prediction

    NASA Technical Reports Server (NTRS)

    Fox, George; Salazar, Ronald; Habib-Agahi, Hamid; Dubos, Gregory

    2013-01-01

    Estimating the operational lifetime of satellites and spacecraft is a complex process. Operational lifetime can differ from mission design lifetime for a variety of reasons. Unexpected mortality can occur due to human errors in design and fabrication, to human errors in launch and operations, to random anomalies of hardware and software or even satellite function degradation or technology change, leading to unrealized economic or mission return. This study focuses on data collection of public information using, for the first time, a large, publically available dataset, and preliminary analysis of satellite lifetimes, both operational lifetime and design lifetime. The objective of this study is the illustration of the relationship of design life to actual lifetime for some representative classes of satellites and spacecraft. First, a Weibull and Exponential lifetime analysis comparison is performed on the ratio of mission operating lifetime to design life, accounting for terminated and ongoing missions. Next a Kaplan-Meier survivor function, standard practice for clinical trials analysis, is estimated from operating lifetime. Bootstrap resampling is used to provide uncertainty estimates of selected survival probabilities. This study highlights the need for more detailed databases and engineering reliability models of satellite lifetime that include satellite systems and subsystems, operations procedures and environmental characteristics to support the design of complex, multi-generation, long-lived space systems in Earth orbit.

  20. Lifetime antecedents of cognitive reserve.

    PubMed

    Richards, Marcus; Sacker, Amanda

    2003-08-01

    We used path analysis on data from the British 1946 birth cohort to model lifetime antecedents of cognitive reserve, represented by the NART at 53 years, and compared this model for verbal memory and psychomotor function at this age, cognitive outcomes that are sensitive to age-associated decline. We showed independent paths from childhood cognition, educational attainment and adult occupation to cognitive reserve, with that from childhood cognition the strongest, and that from adult occupation the weakest. A similar pattern was found for the verbal memory and psychomotor outcomes, although the pathways were weaker than those to the NART. The pattern was also mirrored by the paths from paternal occupation to childhood cognition, educational attainment and adult occupation, with that to childhood cognition the strongest, and that to adult occupation the weakest. The direct influence of paternal occupation on cognitive reserve was negligible, and almost entirely mediated by childhood cognitive ability and educational attainment.

  1. Lifetime estimation of high power lasers

    NASA Astrophysics Data System (ADS)

    Lu, Guoguang; Huang, Yun; En, Yunfei

    2010-11-01

    We have set up a computer automated controlled diode array reliability experiment which can take up 10 to 20 high power cm-bars. Subsequent 25°C and 50°C lifetime tests were completed. According to the method of least squares, the degradation model of cm-bars is obtained. Using the model and weibull++7 software, the extrapolated lifetime of cmbars at 25°C is 7950 hours (2.86×109 shots). We also obtain an acceleration factor 1.88 of resulting in a thermal activation energy of Ea=0.21eV using Arrhenius function. Finally, failure analysis was carried on the gradually degraded devices, the results show that it is the facet degradation which made high power cm-bars degrade during the long time lifetime test.

  2. Tropospheric hydroxyl concentrations and the lifetimes of hydrochlorofluorocarbons (HCFCs)

    NASA Technical Reports Server (NTRS)

    Prather, Michael J.

    1990-01-01

    Three dimensional fields of modeled tropospheric OH concentrations are used to calculate lifetimes against destruction by OH for many hydrogenated halocarbons, including the CFC alternatives. The OH fields were taken from a 3-D chemical transport model (Spivakovsky et al. 1989) that accurately simulates the global measurements of methyl chloroform (derived lifetime of 5.5 years). The lifetimes of various hydro-halocarbons are shown to be insensitive to possible spatial variations and seasonal cycles. It is possible to scale the HCFC lifetimes to that of methyl chloroform or methane by using the ratio of the rate coefficients for reaction with OH at an appropriate temperature, about 277 K.

  3. Influence of age, sex and calendar year on lifetime accumulated red bone marrow dose from diagnostic radiation exposure.

    PubMed

    Hoffmann, Wolfgang; Meiboom, Merle Friederike; Weitmann, Kerstin; Terschüren, Claudia; von Boetticher, Heiner

    2013-01-01

    Our aim is to evaluate the relevance of different factors influencing lifetime accumulated red bone marrow dose, such as calendar year, age and sex. The lifetime dose was estimated for controls interviewed in person (N = 2811, 37.5% women) of the population-based representative Northern Germany Leukemia and Lymphoma Study. Data were assessed in standardized computer-assisted personal interviews. The calculation of doses is based on a comprehensive quantification model including calendar year, sex, kind of examination, and technical development. In multivariate regression models the annual red bone marrow dose was analyzed depending on age, sex and calendar year to consider simultaneously temporal changes in radiologic practice and individual risk factors. While the number of examinations continuously rises over time, the dose shows two peaks around 1950 and after 1980. Men are exposed to higher doses than woman. Until 1970 traditional examinations like conventional and mass screening examinations caused the main dose. They were then replaced by technically advanced examinations mainly computed tomography and cardiac catheter. The distribution of the red bone marrow dose over lifetime depends highly on the technical standards and radiation protection survey. To a lesser extent it is influenced by age and sex of the subjects. Thus epidemiological studies concerning the assessment of radiation exposure should consider the calendar year in which the examination was conducted.

  4. Lifetime income patterns and alcohol consumption: investigating the association between long- and short-term income trajectories and drinking.

    PubMed

    Cerdá, Magdalena; Johnson-Lawrence, Vicki D; Galea, Sandro

    2011-10-01

    Lifetime patterns of income may be an important driver of alcohol use. In this study, we evaluated the relationship between long-term and short-term measures of income and the relative odds of abstaining, drinking lightly-moderately and drinking heavily. We used data from the US Panel Study on Income Dynamics (PSID), a national population-based cohort that has been followed annually or biannually since 1968. We examined 3111 adult respondents aged 30-44 in 1997. Latent class growth mixture models with a censored normal distribution were used to estimate income trajectories followed by the respondent families from 1968 to 1997, while repeated measures multinomial generalized logit models estimated the odds of abstinence (no drinks per day) or heavy drinking (at least 3 drinks a day), relative to light/moderate drinking (<1-2 drinks a day), in 1999-2003. Lower income was associated with higher odds of abstinence and of heavy drinking, relative to light/moderate drinking. For example, belonging to a household with stable low income ($11-20,000) over 30 years was associated with 1.57 odds of abstinence, and 2.14 odds of heavy drinking in adulthood. The association between lifetime income patterns and alcohol use decreased in magnitude and became non-significant once we controlled for past-year income, education and occupation. Lifetime income patterns may have an indirect association with alcohol use, mediated through current socioeconomic conditions.

  5. Prevalence of mood and anxiety disorder in self reported irritable bowel syndrome (IBS). An epidemiological population based study of women

    PubMed Central

    2010-01-01

    Background Irritable bowel syndrome (IBS) is commonly regarded as a functional disorder, and is hypothesized to be associated with anxiety and depression. This evidence mainly rests on population-based studies utilising self-report screening instruments for psychopathology. Other studies applying structured clinical interviews are generally based on small clinical samples, which are vulnerable to biases. The extant evidence base for an association between IBS and psychopathology is hence not conclusive. The aim of this study was therefore to re-examine the hypothesis using population-based data and psychiatric morbidity established with a structured clinical interview. Methods Data were derived from a population-based epidemiological study (n = 1077). Anxiety and mood disorders were established using the Structured Clinical Interview for DSM-IV-TR (SCID-I/NP) and the General Health Questionnaire (GHQ-12). Current and lifetime IBS was self-reported. Hypertension and diabetes were employed as comparison groups as they are expected to be unrelated to mental health. Results Current IBS (n = 69, 6.4%) was associated with an increased likelihood of current mood and/or anxiety disorders (OR = 2.62, 95%CI 1.49 - 4.60). Half the population reporting a lifetime IBS diagnosis also had a lifetime mood or anxiety disorder. Exploratory analyses demonstrated an increased prevalence of IBS across most common anxiety and mood disorders, the exception being bipolar disorder. The association with IBS and symptoms load (GHQ-12) followed a curved dose response pattern. In contrast, hypertension and diabetes were consistently unrelated to psychiatric morbidity. Conclusions IBS is significantly associated with anxiety and mood disorders. This study provides indicative evidence for IBS as a disorder with a psychosomatic aspect. PMID:20687933

  6. Lifetime measurement of high spin states in (75) Kr

    SciTech Connect

    Sheikh, Javid; Trivedi, T.; Maurya, K.; Mehrotra, I.; Palit, R.; Naik, Z.; Jain, H. C.; Negi, D.; Mahanto, G.; Kumar, R.; Singh, R.P.; Muralithar, S.; Pancholi, S.C.; Bhowmik, R.K.; Yang, Y-C; Sun, Y.; Dahl, A.; Raju, M.K.; Appannababu, S.; Kumar, S.; Choudhury, D.; Jain, A. K.

    2010-01-01

    The lifetimes of high spin states of {sup 75}Kr have been determined via {sup 50}Cr ({sup 28}Si, 2pn) {sup 75}Kr reaction in positive parity band using the Doppler-shift attenuation method. The transition quadrupole moments Q deduced from lifetime measurements have been compared with {sup 75}Br. Experimental results obtained from lifetime measurement are interpreted in the framework of projected shell model.

  7. Association of Lifetime Intellectual Enrichment with Cognitive Decline in the Older Population

    PubMed Central

    Vemuri, Prashanthi; Lesnick, Timothy G.; Przybelski, Scott A.; Machulda, Mary; Knopman, David S.; Mielke, Michelle M.; Roberts, Rosebud O.; Geda, Yonas E.; Rocca, Walter A.; Petersen, Ronald C.; Jack, Clifford R.

    2014-01-01

    IMPORTANCE Intellectual lifestyle enrichment throughout life is increasingly viewed as a protective strategy against commonly observed cognitive decline in the elderly. OBJECTIVE To investigate the association of lifetime intellectual enrichment with baseline cognitive performance and rate of cognitive decline in a non-demented elderly population and to estimate difference (in years) associated with lifetime intellectual enrichment to the onset of cognitive impairment. DESIGN, SETTING, PARTICIPANTS Prospective analysis of subjects enrolled in the Mayo Clinic Study of Aging (MCSA), a longitudinal population-based study of cognitive aging in Olmsted County, Minnesota. We studied 1995 non-demented (1718 cognitively normal, 277 MCI) participants in MCSA who completed intellectual lifestyle measures at baseline and underwent at least one follow-up visit. MAIN OUTCOMES AND MEASURES We studied the effect of lifetime intellectual enrichment by separating the variables into two non-overlapping principal components: education/occupation-score and mid/late-life cognitive activity measure based on self-report questionnaires. A global cognitive Z-score served as our summary cognition measure. We used linear mixed-effects models to investigate the associations of demographic and intellectual enrichment measures with global cognitive Z-score trajectories. RESULTS Baseline cognitive performance was lower in older subjects and in those with lower education/occupation, lower mid/late-life cognitive activity, apolipoprotein E4 (APOE) genotype, and in men. The interaction between the two intellectual enrichment measures was significant such that the beneficial effect of mid/late-life cognitive activity on baseline cognitive performance was reduced with increasing education/occupation. Only baseline age, mid/late-life cognitive activity, and APOE4 genotype were significantly associated with longitudinal change in cognitive performance from baseline. For APOE4 carriers with high

  8. Protective effect of Aronia melanocarpa polyphenols against cadmium-induced disorders in bone metabolism: a study in a rat model of lifetime human exposure to this heavy metal.

    PubMed

    Brzóska, Malgorzata M; Rogalska, Joanna; Galazyn-Sidorczuk, Malgorzata; Jurczuk, Maria; Roszczenko, Alicja; Tomczyk, Michal

    2015-03-05

    It was investigated, in a female rat model of low and moderate lifetime human exposure to cadmium (Cd), whether polyphenols from Aronia melanocarpa berries (chokeberry; AMP) may offer protection from this heavy metal-induced disorders in bone metabolism. For this purpose, numerous indices of bone formation (osteocalcin, alkaline phosphatase, osteoprotegerin) and resorption (carboxy-terminal cross-linking telopeptides of type I collagen, soluble receptor activator of nuclear factor-κB ligand) in the serum and/or distal femur epiphysis (trabecular bone region), as well as bone mineral status (volumetric bone mineral density of the femur and content of mineral components, including calcium, in the bone tissue at the distal femur epiphysis) were evaluated in female Wistar rats that received a 0.1% aqueous extract of AMP, as the only drinking fluid (prepared from lyophilized extract by Adamed Consumer Healthcare), and/or Cd in diet (1 and 5mg/kg) for 3, 10, 17, and 24 months. Examination of the phytochemical profile of the aronia extract revealed high content of polyphenols (612.40 ± 3.33 mg/g), including anthocyanins, proanthocyanidins, phenolic acids, and flavonoids. Among detected compounds anthocyanins were identified as dominating. The exposure to Cd, dose- and duration-dependently, enhanced resorption and inhibited formation of the bone tissue resulting in its decreased mineralization. The administration of AMP under the exposure to 1 and 5 mgCd/kg diet provided important protection from this heavy metal-induced disturbances in the bone turnover and changes in the bone mineral status, and the beneficial impact of polyphenols resulted from their independent action and interaction with Cd. These findings suggest that consumption of Aronia melanocarpa polyphenols may play a role in prevention against female skeleton damage due to chronic exposure to Cd and that chokeberry represents the good natural plant candidate for further investigations of its prophylactic use

  9. Disease management to population-based health: steps in the right direction?

    PubMed

    Sprague, Lisa

    2003-05-16

    This issue brief reviews the evolution of the disease management model and the ways it relates to care coordination and case management approaches. It also looks at examples of population-based disease management programs operating in both the private and public sectors and reviews the evidence of their success. Finally, the paper considers the policy implications of adapting this model to a Medicare fee-for-service population.

  10. Lifetime statistics in chaotic dielectric microresonators

    SciTech Connect

    Schomerus, Henning; Wiersig, Jan; Main, Joerg

    2009-05-15

    We discuss the statistical properties of lifetimes of electromagnetic quasibound states in dielectric microresonators with fully chaotic ray dynamics. Using the example of a resonator of stadium geometry, we find that a recently proposed random-matrix model very well describes the lifetime statistics of long-lived resonances, provided that two effective parameters are appropriately renormalized. This renormalization is linked to the formation of short-lived resonances, a mechanism also known from the fractal Weyl law and the resonance-trapping phenomen0008.

  11. Cubosomes for in vivo fluorescence lifetime imaging

    NASA Astrophysics Data System (ADS)

    Biffi, Stefania; Andolfi, Laura; Caltagirone, Claudia; Garrovo, Chiara; Falchi, Angela M.; Lippolis, Vito; Lorenzon, Andrea; Macor, Paolo; Meli, Valeria; Monduzzi, Maura; Obiols-Rabasa, Marc; Petrizza, Luca; Prodi, Luca; Rosa, Antonella; Schmidt, Judith; Talmon, Yeshayahu; Murgia, Sergio

    2017-02-01

    Herein we provided the first proof of principle for in vivo fluorescence optical imaging application using monoolein-based cubosomes in a healthy mouse animal model. This formulation, administered at a non-cytotoxic concentration, was capable of providing both exogenous contrast for NIR fluorescence imaging with very high efficiency and chemospecific information upon lifetime analysis. Time-resolved measurements of fluorescence after the intravenous injection of cubosomes revealed that the dye rapidly accumulated mainly in the liver, while lifetimes profiles obtained in vivo allowed for discriminating between free dye or dye embedded within the cubosome nanostructure after injection.

  12. Touschek Lifetime Calculations for NSLS-II

    SciTech Connect

    Nash,B.; Kramer, S.

    2009-05-04

    The Touschek effect limits the lifetime for NSLS-II. The basic mechanism is Coulomb scattering resulting in a longitudinal momentum outside the momentum aperture. The momentum aperture results from a combination of the initial betatron oscillations after the scatter and the non-linear properties determining the resultant stability. We find that higher order multipole errors may reduce the momentum aperture, particularly for scattered particles with energy loss. The resultant drop in Touschek lifetime is minimized, however, due to less scattering in the dispersive regions. We describe these mechanisms, and present calculations for NSLS-II using a realistic lattice model including damping wigglers and engineering tolerances.

  13. Cubosomes for in vivo fluorescence lifetime imaging.

    PubMed

    Biffi, Stefania; Andolfi, Laura; Caltagirone, Claudia; Garrovo, Chiara; Falchi, Angela M; Lippolis, Vito; Lorenzon, Andrea; Macor, Paolo; Meli, Valeria; Monduzzi, Maura; Obiols-Rabasa, Marc; Petrizza, Luca; Prodi, Luca; Rosa, Antonella; Schmidt, Judith; Talmon, Yeshayahu; Murgia, Sergio

    2017-02-03

    Herein we provided the first proof of principle for in vivo fluorescence optical imaging application using monoolein-based cubosomes in a healthy mouse animal model. This formulation, administered at a non-cytotoxic concentration, was capable of providing both exogenous contrast for NIR fluorescence imaging with very high efficiency and chemospecific information upon lifetime analysis. Time-resolved measurements of fluorescence after the intravenous injection of cubosomes revealed that the dye rapidly accumulated mainly in the liver, while lifetimes profiles obtained in vivo allowed for discriminating between free dye or dye embedded within the cubosome nanostructure after injection.

  14. Lifetime Estimation of High Power White LEDs

    NASA Astrophysics Data System (ADS)

    Ishizaki, Shinya; Kimura, Hideyoshi; Sugimoto, Masaru

    We have developed a high power and long lifetime white LED module which can be used in general lighting applications. Since the materials in the package are very robust at high temperatures, the device can be operated at junction temperatures (Tj) over 250°C. Moreover, the thermal resistance of the package is less than 20°C/W. Therefore the device can be operated at input power as high as 2.4 W, making it possible to shorten the duration of accelerated lifetime tests. An acceleration ratio greater than 100 has been achieved. Assuming a thermally activated degradation process and applying the Arrhenius model, the LED chip lifetime (defined as a 50% reduction in luminous flux) is determined to be 40,000 hours for a Tj of 130°C. The activation energy of the degradation process was determined to be 1.55 eV.

  15. Energy Savings Lifetimes and Persistence

    SciTech Connect

    Hoffman, Ian M.; Schiller, Steven R.; Todd, Annika; Billingsley, Megan A.; Goldman, Charles A.; Schwartz, Lisa C.

    2016-02-01

    This technical brief explains the concepts of energy savings lifetimes and savings persistence and discusses how program administrators use these factors to calculate savings for efficiency measures, programs and portfolios. Savings lifetime is the length of time that one or more energy efficiency measures or activities save energy, and savings persistence is the change in savings throughout the functional life of a given efficiency measure or activity. Savings lifetimes are essential for assessing the lifecycle benefits and cost effectiveness of efficiency activities and for forecasting loads in resource planning. The brief also provides estimates of savings lifetimes derived from a national collection of costs and savings for electric efficiency programs and portfolios.

  16. Lifetime-weighted photoacoustic imaging

    NASA Astrophysics Data System (ADS)

    Forbrich, A.; Shao, P.; Shi, W.; Zemp, Roger J.

    2016-12-01

    Photoacoustic (PA) imaging has been utilized to quantify the lifetime profile of exogenous agents using a series of pump-probe pulses with a varying time delay; however, current techniques typically lead to long acquisition times which are sensitive to motion and cause absorption or photobleaching. We introduce a technique called lifetime-weighted imaging, which uses only three laser pulses to preferentially weight signals from chromophores with long lifetimes (including exogenous contrast agents with triplet excited states such as methylene blue and porphyrins) while nulling chromophores with short picosecond- to nanosecond-scale lifetimes (including hemoglobin). This technique detects the PA signal from a probe pulse either with or without a pump pulse. By subtracting the probe-only signal from the pump-present probe signal, we effectively eliminate signals from chromophores with short lifetimes while preserving PA signals from chromophores with long-lifetimes. We demonstrate the oxygen-dependent lifetime of both methylene blue and porphyrin-lipids and demonstrate both ground-state recovery and excited-state lifetime-weighted imaging. Lifetime-weighted PA imaging may have applications in many molecular imaging application including: photodynamic therapy dosimetry guidance and oxygen sensing.

  17. Increasing incidence of cataract surgery: Population-based study

    PubMed Central

    Gollogly, Heidrun E.; Hodge, David O.; St. Sauver, Jennifer L.; Erie, Jay C.

    2015-01-01

    PURPOSE To estimate the incidence of cataract surgery in a defined population and to determine longitudinal cataract surgery patterns. SETTING Mayo Clinic, Rochester, Minnesota, USA. DESIGN Cohort study. METHODS Rochester Epidemiology Project (REP) databases were used to identify all incident cataract surgeries in Olmsted County, Minnesota, between January 1, 2005, and December 31, 2011. Age-specific and sex-specific incidence rates were calculated and adjusted to the 2010 United States white population. Data were merged with previous REP data (1980 to 2004) to assess temporal trends in cataract surgery. Change in the incidence over time was assessed by fitting generalized linear models assuming a Poisson error structure. The probability of second-eye cataract surgery was calculated using the Kaplan-Meier method. RESULTS Included were 8012 cataract surgeries from 2005 through 2011. During this time, incident cataract surgery significantly increased (P < .001), peaking in 2011 with a rate of 1100 per 100 000 (95% confidence interval, 1050–1160). The probability of second-eye surgery 3, 12, and 24 months after first-eye surgery was 60%, 76%, and 86%, respectively, a significant increase compared with the same intervals in the previous 7 years (1998 to 2004) (P < .001). When merged with 1980 to 2004 REP data, incident cataract surgery steadily increased over the past 3 decades (P < .001). CONCLUSION Incident cataract surgery steadily increased over the past 32 years and has not leveled off, as reported in Swedish population-based series. Second-eye surgery was performed sooner and more frequently, with 60% of residents having second-eye surgery within 3-months of first-eye surgery. PMID:23820302

  18. Distributions of personal VOC exposures: a population-based analysis.

    PubMed

    Jia, Chunrong; D'Souza, Jennifer; Batterman, Stuart

    2008-10-01

    Information regarding the distribution of volatile organic compound (VOC) concentrations and exposures is scarce, and there have been few, if any, studies using population-based samples from which representative estimates can be derived. This study characterizes distributions of personal exposures to ten different VOCs in the U.S. measured in the 1999--2000 National Health and Nutrition Examination Survey (NHANES). Personal VOC exposures were collected for 669 individuals over 2-3 days, and measurements were weighted to derive national-level statistics. Four common exposure sources were identified using factor analyses: gasoline vapor and vehicle exhaust, methyl tert-butyl ether (MBTE) as a gasoline additive, tap water disinfection products, and household cleaning products. Benzene, toluene, ethyl benzene, xylenes chloroform, and tetrachloroethene were fit to log-normal distributions with reasonably good agreement to observations. 1,4-Dichlorobenzene and trichloroethene were fit to Pareto distributions, and MTBE to Weibull distribution, but agreement was poor. However, distributions that attempt to match all of the VOC exposure data can lead to incorrect conclusions regarding the level and frequency of the higher exposures. Maximum Gumbel distributions gave generally good fits to extrema, however, they could not fully represent the highest exposures of the NHANES measurements. The analysis suggests that complete models for the distribution of VOC exposures require an approach that combines standard and extreme value distributions, and that carefully identifies outliers. This is the first study to provide national-level and representative statistics regarding the VOC exposures, and its results have important implications for risk assessment and probabilistic analyses.

  19. Young adults' trajectories of Ecstasy use: a population based study.

    PubMed

    Smirnov, Andrew; Najman, Jake M; Hayatbakhsh, Reza; Plotnikova, Maria; Wells, Helene; Legosz, Margot; Kemp, Robert

    2013-11-01

    Young adults' Ecstasy use trajectories have important implications for individual and population-level consequences of Ecstasy use, but little relevant research has been conducted. This study prospectively examines Ecstasy trajectories in a population-based sample. Data are from the Natural History Study of Drug Use, a retrospective/prospective cohort study conducted in Australia. Population screening identified a probability sample of Ecstasy users aged 19-23 years. Complete data for 30 months of follow-up, comprising 4 time intervals, were available for 297 participants (88.4% of sample). Trajectories were derived using cluster analysis based on recent Ecstasy use at each interval. Trajectory predictors were examined using a generalized ordered logit model and included Ecstasy dependence (World Mental Health Composite International Diagnostic Instrument), psychological distress (Hospital Anxiety Depression Scale), aggression (Young Adult Self Report) and contextual factors (e.g. attendance at electronic/dance music events). Three Ecstasy trajectories were identified (low, intermediate and high use). At its peak, the high-use trajectory involved 1-2 days Ecstasy use per week. Decreasing frequency of use was observed for intermediate and high-use trajectories from 12 months, independently of market factors. Intermediate and high-use trajectory membership was predicted by past Ecstasy consumption (>70 pills) and attendance at electronic/dance music events. High-use trajectory members were unlikely to have used Ecstasy for more than 3 years and tended to report consistently positive subjective effects at baseline. Given the social context and temporal course of Ecstasy use, Ecstasy trajectories might be better understood in terms of instrumental rather than addictive drug use patterns.

  20. Stratification of ALS patients' survival: a population-based study.

    PubMed

    Marin, Benoît; Couratier, Philippe; Arcuti, Simona; Copetti, Massimiliano; Fontana, Andrea; Nicol, Marie; Raymondeau, Marie; Logroscino, Giancarlo; Preux, Pierre Marie

    2016-01-01

    The natural history of amyotrophic lateral sclerosis (ALS) and patient risk stratification are areas of considerable research interest. We aimed (1) to describe the survival of a representative cohort of French ALS patients, and (2) to identify covariates associated with various patterns of survival using a risk classification analysis. ALS patients recruited in the FRALim register (2000-2013) were included. Time-to-death analyses were performed using Kaplan-Meier method and Cox model. A recursive partitioning and amalgamation (RECPAM) algorithm analysis identified subgroups of patients with different patterns of survival. Among 322 patients, median survival times were 26.2 and 15.6 months from time of onset and of diagnosis, respectively. Four groups of patients were identified, depending on their baseline characteristics and survival (1) ALSFRS-R slope >0.46/month and definite or probable ALS (median survival time (MST) 10.6 months); (2) ALSFRS-R slope >0.46/month and possible or probable laboratory-supported ALS (MST: 18.1 months); (3) ALSFRS-R slope ≤0.46/month and definite or probable ALS (MST: 22.5 months), and (4) ALSFRS-R slope ≤0.46/month and possible or probable laboratory-supported ALS (MST: 37.6 months). Median survival time is among the shortest ever reported by a worldwide population-based study. This is probably related to the age structure of the patients (the oldest identified to date), driven by the underlying population (30 % of subjects older than 60 years). Further research in the field of risk stratification could help physicians better anticipate prognosis of ALS patients, and help improve the design of randomized controlled trials.

  1. Tremendously increased lifetime of MCP-PMTs

    NASA Astrophysics Data System (ADS)

    Lehmann, A.; Britting, A.; Eyrich, W.; Pfaffinger, M.; Uhlig, F.; Belias, A.; Dzhygadlo, R.; Gerhardt, A.; Götzen, K.; Kalicy, G.; Krebs, M.; Lehmann, D.; Nerling, F.; Patsyuk, M.; Peters, K.; Schepers, G.; Schmitt, L.; Schwarz, C.; Schwiening, J.; Traxler, M.; Zühlsdorf, M.; Düren, M.; Etzelmüller, E.; Föhl, K.; Hayrapetyan, A.; Kröck, B.; Merle, O.; Rieke, J.; Schmidt, M.; Cowie, E.; Keri, T.; Achenbach, P.; Cardinali, M.; Hoek, M.; Lauth, W.; Schlimme, S.; Sfienti, C.; Thiel, M.

    2017-02-01

    Microchannel plate (MCP) PMTs are very attractive photon sensors for low light level applications in strong magnetic fields. However, until recently the main drawback of MCP-PMTs was their aging behavior which manifests itself in a limited lifetime due to a rapidly decreasing quantum efficiency (QE) of the photo cathode (PC) as the integrated anode charge (IAC) increases. In the latest models of PHOTONIS, Hamamatsu, and BINP novel techniques are applied to avoid these aging effects which are supposed to be mainly caused by feedback ion impinging on the PC and damaging it. For more than four years we are running a long-term aging test with new lifetime-enhanced MCP-PMT models by simultaneously illuminating various PMTs with roughly the same photon rate. This allows a fair comparison of the lifetime of all investigated MCP-PMTs and will give some insight into the best techniques to be applied for a lifetime enhancement. In this paper the results of comprehensive aging tests will be discussed. Gain, dark count rate and QE were investigated for their dependence on the IAC. The QE was measured spectrally resolved and as a function of the position across the PC to identify regions where the damage develops first. For the best performing tubes the lifetime improvement compared to former MCP-PMTs is a factor of ∼ 50 based on an IAC of meanwhile > 10 C /cm2. This breakthrough in the lifetime of MCP-PMTs was achieved by coating the MCP pores with an atomic layer deposition (ALD) technique.

  2. Analysis of lifetime control in high-voltage IGBTs

    NASA Astrophysics Data System (ADS)

    Yuan, X.; Udrea, F.; Coulbeck, L.; Waind, P. R.; Amaratunga, G. A. J.

    2002-01-01

    This paper discusses the effectiveness of the lifetime control technology in high-voltage insulated gate bipolar transistors (IGBTs) by using both numerical simulations and a two-dimensional on-state analytical model specifically developed for IGBTs with local lifetime killing. A comprehensive study of the static and dynamic performance of IGBTs using lifetime control technology in comparison with IGBTs featuring reduced anode injection efficiency structures is made. We show for the first time that IGBTs with low anode injection efficiency have similar or better on-state/switching trade-off when compared to equivalent IGBTs using lifetime control technology. We also show that both the local lifetime control and the low anode injection efficiency techniques are superior to full irradiation. The low anode injection efficiency is particularly better than the local lifetime control technique when applied to punch-though IGBTs while no difference between the two is found in non-punch-though IGBTs.

  3. Traffic congestion and the lifetime of networks with moving nodes

    NASA Astrophysics Data System (ADS)

    Yang, Xianxia; Li, Jie; Pu, Cunlai; Yan, Meichen; Sharafat, Rajput Ramiz; Yang, Jian; Gakis, Konstantinos; Pardalos, Panos M.

    2017-01-01

    For many power-limited networks, such as wireless sensor networks and mobile ad hoc networks, maximizing the network lifetime is the first concern in the related designing and maintaining activities. We study the network lifetime from the perspective of network science. In our model, nodes are initially assigned a fixed amount of energy moving in a square area and consume the energy when delivering packets. We obtain four different traffic regimes: no, slow, fast, and absolute congestion regimes, which are basically dependent on the packet generation rate. We derive the network lifetime by considering the specific regime of the traffic flow. We find that traffic congestion inversely affects network lifetime in the sense that high traffic congestion results in short network lifetime. We also discuss the impacts of factors such as communication radius, node moving speed, routing strategy, etc., on network lifetime and traffic congestion.

  4. Traffic congestion and the lifetime of networks with moving nodes.

    PubMed

    Yang, Xianxia; Li, Jie; Pu, Cunlai; Yan, Meichen; Sharafat, Rajput Ramiz; Yang, Jian; Gakis, Konstantinos; Pardalos, Panos M

    2017-01-01

    For many power-limited networks, such as wireless sensor networks and mobile ad hoc networks, maximizing the network lifetime is the first concern in the related designing and maintaining activities. We study the network lifetime from the perspective of network science. In our model, nodes are initially assigned a fixed amount of energy moving in a square area and consume the energy when delivering packets. We obtain four different traffic regimes: no, slow, fast, and absolute congestion regimes, which are basically dependent on the packet generation rate. We derive the network lifetime by considering the specific regime of the traffic flow. We find that traffic congestion inversely affects network lifetime in the sense that high traffic congestion results in short network lifetime. We also discuss the impacts of factors such as communication radius, node moving speed, routing strategy, etc., on network lifetime and traffic congestion.

  5. The use of metabolomics in population-based research.

    PubMed

    Su, L Joseph; Fiehn, Oliver; Maruvada, Padma; Moore, Steven C; O'Keefe, Stephen J; Wishart, David S; Zanetti, Krista A

    2014-11-01

    The NIH has made a significant commitment through the NIH Common Fund's Metabolomics Program to build infrastructure and capacity for metabolomics research, which should accelerate the field. Given this investment, it is the ideal time to start planning strategies to capitalize on the infrastructure being established. An obvious gap in the literature relates to the effective use of metabolomics in large-population studies. Although published reports from population-based studies are beginning to emerge, the number to date remains relatively small. Yet, there is great potential for using metabolomics in population-based studies to evaluate the effects of nutritional, pharmaceutical, and environmental exposures (the "exposome"); conduct risk assessments; predict disease development; and diagnose diseases. Currently, the majority of the metabolomics studies in human populations are in nutrition or nutrition-related fields. This symposium provided a timely venue to highlight the current state-of-science on the use of metabolomics in population-based research. This session provided a forum at which investigators with extensive experience in performing research within large initiatives, multi-investigator grants, and epidemiology consortia could stimulate discussion and ideas for population-based metabolomics research and, in turn, improve knowledge to help devise effective methods of health research.

  6. Population-based public health interventions: innovations in practice, teaching, and management. Part II.

    PubMed

    Keller, Linda Olson; Strohschein, Susan; Schaffer, Marjorie A; Lia-Hoagberg, Betty

    2004-01-01

    The Intervention Wheel is a population-based practice model that encompasses three levels of practice (community, systems, and individual/family) and 17 public health interventions. Each intervention and practice level contributes to improving population health. The Intervention Wheel, previously known as the Public Health Intervention Model, was originally introduced in 1998 by the Minnesota Department of Health, Section of Public Health Nursing (PHN). The model has been widely disseminated and used throughout the United States since that time. The evidence supporting the Intervention Wheel was recently subjected to a rigorous critique by regional and national experts. This critical process, which involved hundreds of public health nurses, resulted in a more robust Intervention Wheel and established the validity of the model. The critique also produced basic steps and best practices for each of the 17 interventions. Part I describes the Intervention Wheel, defines population-based practice, and details the recommended modifications and validation process. Part II provides examples of the innovative ways that the Intervention Wheel is being used in public health/PHN practice, education, and administration. The two articles provide a foundation and vision for population-based PHN practice and direction for improving population health.

  7. Population-based public health interventions: practice-based and evidence-supported. Part I.

    PubMed

    Keller, Linda Olson; Strohschein, Susan; Lia-Hoagberg, Betty; Schaffer, Marjorie A

    2004-01-01

    The Intervention Wheel is a population-based practice model that encompasses three levels of practice (community, systems, and individual/family) and 17 public health interventions. Each intervention and practice level contributes to improving population health. The Intervention Wheel, previously known as the Public Health Intervention Model, was originally introduced in 1998 by the Minnesota Department of Health, Section of Public Health Nursing. The model has been widely disseminated and used throughout the United States since that time. The evidence supporting the Intervention Wheel was recently subjected to a rigorous critique by regional and national experts. This critical process, which involved hundreds of public health nurses, resulted in a more robust Intervention Wheel and established the validity of the model. The critique also produced basic steps and best practices for each of the 17 interventions. Part I describes the Intervention Wheel, defines population-based practice, and details the recommended modifications and validation process. Part II provides examples of the innovative ways that the Intervention Wheel is being used in public health/public health nursing practice, education, and administration. The two articles provide a foundation and vision for population-based public health nursing practice and direction for improving population health.

  8. Same-Sex Behavior and its Relationship with Sexual and Health-Related Practices Among a Population-Based Sample of Women in Puerto Rico: Implications for Cancer Prevention and Control

    PubMed Central

    Soto-Salgado, Marievelisse; Colón-López, Vivian; Perez, Cynthia; Muñoz-Masso, Cristina; Marrero, Edmir; Suárez, Erick; Ortiz, Ana P.

    2017-01-01

    This secondary data analysis aimed to estimate the prevalence of same-sex behavior and sexual and health-related practices of a population-based sample (n=560) of women aged 16-64 years in Puerto Rico (PR). Data collection included interviews and biologic samples. Seven percent of the sample had had sex with other women (WSW). Age-adjusted logistic regression models indicated that WSW had higher odds of history of cancer, having ≥ 7 lifetime sexual partners, using sex toys and sharing them, and use of tobacco and illicit drugs. Future research is needed to address the health needs of WSW, including cancer-related risk factors and sexual practices. PMID:28286595

  9. Occupational exposure to asbestos and lung cancer in men: evidence from a population-based case-control study in eight Canadian provinces

    PubMed Central

    2012-01-01

    Background Asbestos is classified as a human carcinogen, and studies have consistently demonstrated that workplace exposure to it increases the risk of developing lung cancer. Few studies have evaluated risks in population-based settings where there is a greater variety in the types of occupations, and exposures. Methods This was a population based case–control study with 1,681 incident cases of lung cancer, and 2,053 controls recruited from 8 Canadian provinces between 1994 and 1997. Self-reported questionnaires were used to elicit a lifetime occupational history, including general tasks, and information for other risk factors. Occupational hygienists, who were blinded to case–control status, assigned asbestos exposures to each job on the basis of (i) concentration (low, medium, high), (ii) frequency (<5%, 5-30%, and >30% of the time in a normal work week), and (iii) reliability (possible, probable, definite). Logistic regression was used to estimate odds ratios (ORs) and their corresponding 95% confidence intervals (CI). Results Those occupationally exposed to (i) low, and (ii) medium or high concentrations of asbestos had ORs for lung cancer of 1.17 (95% CI=0.92 – 1.50) and 2.16 (95% CI=1.21-3.88), respectively, relative to those who were unexposed. Medium or high exposure to asbestos roughly doubled the risk for lung cancer across all three smoking pack-year categories. The joint relationship between smoking and asbestos was consistent with a multiplicative risk model. Conclusions Our findings provide further evidence that exposure to asbestos has contributed to an increased risk of lung cancer in Canadian workplaces, and suggests that nearly 3% of lung cancers among Canadian men are caused by occupational exposure to asbestos. PMID:23234401

  10. Prevalence of microcephaly in Europe: population based study

    PubMed Central

    Rankin, Judith; Garne, Ester; Loane, Maria; Greenlees, Ruth; Addor, Marie-Claude; Arriola, Larraitz; Barisic, Ingeborg; Bergman, Jorieke E H; Csaky-Szunyogh, Melinda; Dias, Carlos; Draper, Elizabeth S; Gatt, Miriam; Khoshnood, Babak; Klungsoyr, Kari; Kurinczuk, Jennifer J; Lynch, Catherine; McDonnell, Robert; Nelen, Vera; Neville, Amanda J; O’Mahony, Mary T; Pierini, Anna; Randrianaivo, Hanitra; Rissmann, Anke; Tucker, David; Verellen-Dumoulin, Christine; de Walle, Hermien E K; Wellesley, Diana; Wiesel, Awi; Dolk, Helen

    2016-01-01

    Objectives To provide contemporary estimates of the prevalence of microcephaly in Europe, determine if the diagnosis of microcephaly is consistent across Europe, and evaluate whether changes in prevalence would be detected using the current European surveillance performed by EUROCAT (the European Surveillance of Congenital Anomalies). Design Questionnaire and population based observational study. Setting 24 EUROCAT registries covering 570 000 births annually in 15 countries. Participants Cases of microcephaly not associated with a genetic condition among live births, fetal deaths from 20 weeks’ gestation, and terminations of pregnancy for fetal anomaly at any gestation. Main outcome measures Prevalence of microcephaly (1 Jan 2003-31 Dec 2012) analysed with random effects Poisson regression models to account for heterogeneity across registries. Results 16 registries responded to the questionnaire, of which 44% (7/16) used the EUROCAT definition of microcephaly (a reduction in the size of the brain with a skull circumference more than 3 SD below the mean for sex, age, and ethnic origin), 19% (3/16) used a 2 SD cut off, 31% (5/16) were reliant on the criteria used by individual clinicians, and one changed criteria between 2003 and 2012. Prevalence of microcephaly in Europe was 1.53 (95% confidence interval 1.16 to 1.96) per 10 000 births, with registries varying from 0.4 (0.2 to 0.7) to 4.3 (3.6 to 5.0) per 10 000 (χ2=338, df=23, I2=93%). Registries with a 3 SD cut off reported a prevalence of 1.74 per 10 000 (0.86 to 2.93) compared with those with the less stringent 2 SD cut off of 1.21 per 10 000 (0.21 to 2.93). The prevalence of microcephaly would need to increase in one year by over 35% in Europe or by over 300% in a single registry to reach statistical significance (P<0.01). Conclusions EUROCAT could detect increases in the prevalence of microcephaly from the Zika virus of a similar magnitude to those observed in Brazil. Because of the rarity

  11. Spectral dependence of carrier lifetimes in silicon for photovoltaic applications

    NASA Astrophysics Data System (ADS)

    Roller, John F.; Li, Yu-Tai; Dagenais, Mario; Hamadani, Behrang H.

    2016-12-01

    Charge carrier lifetimes in photovoltaic-grade silicon wafers were measured by a spectral-dependent, quasi-steady-state photoconductance technique. Narrow bandwidth light emitting diodes were used to excite excess charge carriers within the material, and the effective lifetimes of these carriers were measured as a function of wavelength and intensity. The dependence of the effective lifetime on the excitation wavelength was then analyzed within the context of an analytical model relating effective lifetime to the bulk lifetime and surface recombination velocity of the material. The agreement between the model and the experimental data provides validation for this technique to be used at various stages of the solar cell production line to investigate the quality of the passivation layers and the bulk properties of the material.

  12. High energy beam lifetime analysis

    SciTech Connect

    Howell, R.H.; Sterne, P.A.; Hartley, J.; Cowan, T.E.

    1997-05-01

    We have developed a positron lifetime defect analysis capability based on a 3 MeV electrostatic accelerator. The high energy beam lifetime spectrometer is operational with a 60 mCi {sup 22}Na source providing a current of 7 10{sup 5} positrons per second. Lifetime data are derived from a thin plastic transmission detector providing an implantation time and a BaF{sub 2} detector to determine the annihilation time. Positron lifetime analysis is performed with a 3 MeV positron beam on thick sample specimens at counting rates in excess of 2000 per second. The instrument is being used for bulk sample analysis and analysis of samples encapsulated in controlled environments for in situ measurements.

  13. Measurement of the tau lifetime

    SciTech Connect

    Jaros, J.A.

    1982-10-01

    If the tau lepton couples to the charged weak current with universal strength, its lifetime can be expressed in terms of the muon's lifetime, the ratio of the masses of the muon and the tau, and the tau's branching ratio into e anti nu/sub e/ nu/sub tau/ as tau/sub tau/ = tau/sub ..mu../ (m/sub ..mu..//m/sub tau/)/sup 5/ B(tau ..-->.. e anti nu/sub e/nu/sub tau/) = 2.8 +- 0.2 x 10/sup -13/ s. This paper describes the measurement of the tau lifetime made by the Mark II collaboration, using a new high precision drift chamber in contunction with the Mark II detector at PEP. The results of other tau lifetime measurements are summarized.

  14. Parallel genetic algorithm with population-based sampling approach to discrete optimization under uncertainty

    NASA Astrophysics Data System (ADS)

    Subramanian, Nithya

    the laminate stiffness matrix implements a square fiber model with a fiber volume fraction sample. The calculations to establish the expected values of constraints and fitness values use the Classical Laminate Theory. The non-deterministic constraints enforced include the probability of satisfying the Tsai-Hill failure criterion and the maximum strain limit. The results from a deterministic optimization, optimization under uncertainty using Monte Carlo sampling and Population-Based Sampling are studied. Also, the work investigates the effectiveness of running the fitness analyses in parallel and the sampling scheme in parallel. Overall, the work conducted for this thesis demonstrated the efficacy of the GA with Population-Based Sampling for the focus problem and established improvements over previous implementations of the GA with PBS.

  15. LETTER TO THE EDITOR: The Mott metal - insulator transition in the two-dimensional Hubbard model at half-filling with lifetime effects within the moment approach

    NASA Astrophysics Data System (ADS)

    Rodríguez-Núñez, J. J.; Schafroth, S.

    1998-06-01

    We explore the effect of the self-energy, 0953-8984/10/23/002/img5, having a single pole, 0953-8984/10/23/002/img6, with spectral weight 0953-8984/10/23/002/img7 and quasi-particle lifetime 0953-8984/10/23/002/img8, on the density of states. We obtain the set of parameters 0953-8984/10/23/002/img6, 0953-8984/10/23/002/img7, and 0953-8984/10/23/002/img8 by means of the moment approach (exact sum rules) of Nolting. Due to our choice of self-energy, the system is not a Fermi liquid for any value of the interaction, a result which also holds in the moment approach of Nolting without lifetime effects. Our self-energy satisfies the Kramers - Kronig relationships since it is analytic in one of the complex half-planes. By increasing the value of the local interaction, 0953-8984/10/23/002/img12, at half-filling 0953-8984/10/23/002/img13, there is a transition from a paramagnetic metal to a paramagnetic insulator (a Mott metal - insulator transition) for values of 0953-8984/10/23/002/img12 of the order of 0953-8984/10/23/002/img15 (W is the bandwidth) which is in agreement with numerical results for finite lattices and for an infinite number of dimensions 0953-8984/10/23/002/img16. These results expose the main weakness of the spherical approximation of Nolting: a finite gap for any finite value of the interaction, i.e., an insulator for any finite value of 0953-8984/10/23/002/img12. Lifetime effects are absolutely indispensable to making our scheme work better than that based on improving the narrowing band factor, 0953-8984/10/23/002/img18, beyond that obtained from the spherical approximation of Nolting.

  16. Predicting the lifetime of superlubricity

    NASA Astrophysics Data System (ADS)

    Wang, Anle; He, Qichang; Xu, Zhiping

    2015-12-01

    The concept of superlubricity has recently called upon notable interest after the demonstration of ultralow friction between atomistically smooth surfaces in layered materials. However, the energy dissipation process conditioning the sustainability of a superlubric state has not yet been well understood. In this work, we address this issue by performing dynamic simulations based on both full-atom and reduced Frenkel-Kontorova models. We find that the center-of-mass momentum autocorrelation of a sliding object can be used as a statistical indicator of the state of superlubricity. Beyond a critical value of it, the sliding motion experiences a catastrophic breakdown with a dramatically high rate of energy dissipation, caused by the inter-vibrational-mode coupling. By tracking this warning signal, one can extract heat from modes other than the translation to avoid the catastrophe and extend the lifetime of superlubricity. This concept is demonstrated in double-walled carbon-nanotubes-based nanomechanical devices with the indicator-based feedback design implemented.

  17. Posttraumatic stress disorder across two generations: concordance and mechanisms in a population-based sample

    PubMed Central

    Roberts, Andrea L.; Galea, Sandro; Austin, S. Bryn; Cerda, Magdalena; Wright, Rosalind J.; Rich-Edwards, Janet W.; Koenen, Karestan C.

    2012-01-01

    Background Research conducted using small samples of persons exposed to extreme stressors has documented an association between parental and offspring posttraumatic stress disorder (PTSD), but it is unknown whether this association exists in the general population and whether trauma exposure mediates this association. We sought to determine whether mothers’ posttraumatic stress symptoms were associated with PTSD in their young adult children and whether this association was mediated by higher trauma exposure in children of women with PTSD. Methods Using data from a cohort of mothers (n=6924) and a cohort of their children (n=8453), we calculated risk ratios (RR) for child’s PTSD and examined mediation by trauma exposure. Results Mother’s lifetime posttraumatic stress symptoms were associated with child’s PTSD in dose-response fashion (mother’s 1 to 3 symptoms, child’s RR=1.2; mother’s 4-5 symptoms, RR=1.3; mother’s 6-7 symptoms, RR=1.6, compared to children of mothers with no symptoms, p<0.001 for each). Mother’s lifetime symptoms were also associated with child’s trauma exposure in dose-response fashion. Elevated exposure to trauma substantially mediated elevated risk for PTSD in children of women with symptoms (mediation proportion, 74%, p<0.001). Conclusions Intergenerational association of PTSD is clearly present in a large population-based sample. Children of women who had PTSD were more likely than children of women without PTSD to experience traumatic events; this suggests, in part, why the disorder is associated across generations. Health care providers who treat mothers with PTSD should be aware of the higher risk for trauma exposure and PTSD in their children. PMID:22521146

  18. An obesity/cardiometabolic risk reduction disease management program: a population-based approach.

    PubMed

    Villagra, Victor G

    2009-04-01

    Obesity is a critical health concern that has captured the attention of public and private healthcare payers who are interested in controlling costs and mitigating the long-term economic consequences of the obesity epidemic. Population-based approaches to obesity management have been proposed that take advantage of a chronic care model (CCM), including patient self-care, the use of community-based resources, and the realization of care continuity through ongoing communications with patients, information technology, and public policy changes. Payer-sponsored disease management programs represent an important conduit to delivering population-based care founded on similar CCM concepts. Disease management is founded on population-based disease identification, evidence-based care protocols, and collaborative practices between clinicians. While substantial clinician training, technology infrastructure commitments, and financial support at the payer level will be needed for the success of disease management programs in obesity and cardiometabolic risk reduction, these barriers can be overcome with the proper commitment. Disease management programs represent an important tool to combat the growing societal risks of overweight and obesity.

  19. Fluorescence lifetime contrast in small animal imaging

    NASA Astrophysics Data System (ADS)

    Ramanujan, V. Krishnan; Bandyopadhyay, Abhik; Sun, LuZhe; Herman, Brian A.

    2007-02-01

    Early detection of primary tumors is the key for effective therapeutic intervention and successful patient survival. Small animal models emulating human diseases are powerful tools for our comprehensive understanding of the pathophysiology of tumor formation and metastasis to distant sites. Our long-term goal is to develop a non-invasive, multiphoton-fluorescence lifetime imaging (MP-FLIM) modality that can precisely quantify these steps in animal tumor models at a very early stage. The specific hypothesis is that fluorescence lifetime can be employed as reliable contrast parameter for providing higher detection sensitivity as compared with conventional intensity-based tumor imaging approaches and therefore it is possible to detect smaller tumor volumes (early detection) than those achieved by other prevailing methods. We base this hypothesis on our recent observations that (1) fluorescence lifetime is "intrinsic" to the fluorophore and its measurement is not affected by concentration and/or spectral artifacts as in intensity-based methods, (2) multiphoton excitation can enable increased tissue penetrability and reduced phototoxicity and (3) MP-FLIM approach can discriminate background autofluorescence from the fluorescent proteins in thick tissues thereby achieving a ten-fold increase in signal-to-background ratio over the intensity-based approaches. We present our preliminary data to support this hypothesis in primary tumor detection in nu/nu athymic mouse models.

  20. The impact of childhood parental loss on risk for mood, anxiety and substance use disorders in a population-based sample of male twins.

    PubMed

    Otowa, Takeshi; York, Timothy P; Gardner, Charles O; Kendler, Kenneth S; Hettema, John M

    2014-12-15

    Previous studies have identified the relationship between parental loss and psychopathology later in life. However, this relationship varied depending on the kind of loss, the parent involved, and the type of psychopathology. In the present study, we examined the association between parental loss (any loss, death, and separation) during childhood and lifetime risk for seven common psychiatric and substance use disorders in a sample of 2605 male twins from the Virginia population-based twin registry. Using structural equation modeling (SEM), we also examined the extent to which the influence of parental loss contributes to adult psychopathology. Parental separation was associated with a wide range of adult psychopathology, whereas parental death was specifically associated with phobia and alcohol dependence. Maternal and paternal separations were almost equally associated with most forms of psychopathology. SEM suggested that parental loss accounted for about 10% of the variance of adult psychopathology, of which parental separation had the strongest impacts on risk for depression and drug abuse/dependence (11% of the total variance). Our findings suggest that early parental separation has stronger and wider effects on adult psychopathology than parental death.

  1. Neutrinos and cosmology: a lifetime relationship

    SciTech Connect

    Serpico, Pasquale D.; /Fermilab

    2008-06-01

    We consider the example of neutrino decays to illustrate the profound relation between laboratory neutrino physics and cosmology. Two case studies are presented: In the first one, we show how the high precision cosmic microwave background spectral data collected by the FIRAS instrument on board of COBE, when combined with Lab data, have greatly changed bounds on the radiative neutrino lifetime. In the second case, we speculate on the consequence for neutrino physics of the cosmological detection of neutrino masses even as small as {approx}0.06 eV, the lower limit guaranteed by neutrino oscillation experiments. We show that a detection at that level would improve by many orders of magnitude the existing limits on neutrino lifetime, and as a consequence on some models of neutrino secret interactions.

  2. Do quasars have cosmologically long lifetimes

    SciTech Connect

    Chanan, G.A.

    1982-01-01

    Turner and Tyson have independently suggested that the apparent evolution of quasars may be an artifact caused by (unseen) gravitational lenses; some of the problems inherent in the usual picture of space density evolution are thereby avoided. We discuss how these problems may be similarly avoided without invoking any such gravitational effects: apparent (and unreal) density evolution follows as an immediate consequence if quasar lifetimes (the only free parameter in our model) are of the order of 3 x 10/sup 9/ years. If the lifetimes are indeed this long, quasars may occur much less frequently than previously thought but, at the same time, the local density of quasars may have been grossly underestimated.

  3. Changing roles of population-based cancer registries in Australia.

    PubMed

    Roder, David; Creighton, Nicola; Baker, Deborah; Walton, Richard; Aranda, Sanchia; Currow, David

    2015-09-01

    Registries have key roles in cancer incidence, mortality and survival monitoring and in showing disparities across the population. Incidence monitoring began in New South Wales in 1972 and other jurisdictions soon followed. Registry data are used to evaluate outcomes of preventive, screening, treatment and support services. They have shown decreases in cancer incidence following interventions and have been used for workforce and other infrastructure planning. Crude markers of optimal radiotherapy and chemotherapy exist and registry data are used to show shortfalls against these markers. The data are also used to investigate cancer clusters and environmental concerns. Survival data are used to assess service performance and interval cancer data are used in screening accreditation. Registries enable determination of risk of multiple primary cancers. Clinical quality registries are used for clinical quality improvement. Population-based cancer registries and linked administrative data complement clinical registries by providing high-level system-wide data. The USA Commission on Cancer has long used registries for quality assurance and service accreditation. Increasingly population-based registry data in Australia are linked with administrative data on service delivery to assess system performance. Addition oftumour stage and otherprognostic indicators is important forthese analyses and is facilitated by the roll-out of structured pathology reporting. Data linkage with administrative data, following checks on the quality of these data, enables assessment of patterns of care and other performance indicators for health-system monitoring. Australian cancer registries have evolved and increasingly are contributing to broader information networks for health system management.

  4. Sexual Behaviors among Adults in Puerto Rico: A Population-Based Study

    PubMed Central

    Ortiz, Ana Patricia; Soto-Salgado, Marievelisse; Suárez, Erick; Santos-Ortiz, María del Carmen; Tortolero-Luna, Guillermo; Pérez, Cynthia M.

    2012-01-01

    Introduction Given changes in sexual behaviors and norms in the United States, there is a need for current and representative data on sexual behaviors with particular interest in gender, age, and racial/ethnic group differences. Aim Given the limited data for Hispanics and for Puerto Rico (PR), we described patterns of sexual behaviors and characteristics among a sexually active sample (n = 1,575) of adults aged 21–64 years in PR. Main Outcome Measures The main outcome measures for this study are sexual behaviors including age at sexual initiation, number of sexual partners, vaginal and anal intercourse, and oral sex, among others. Methods Data from a population-based cross-sectional study in PR (2005–2008) was analyzed. The prevalence of sexual behaviors and characteristics was described by age-group and gender during the lifetime and in the past 12 months. Results Overall, 96.8%, 81.6%, and 60.9% of participants had ever engaged in vaginal, oral and anal sex, respectively, whereas 23.7% were seropositive to any of the sexually transmitted infections under study. Sexual initiation ≤15 years was reported by 37.8% of men and 21.4% of women; whereas 47.9% of men and 13.2% of women reported to have had ≥7 sexual partners in their lifetime. Approximately, 3% of women and 6% of men reported same-sex sexual practices, while history of forced sexual relations was reported by 9.6% of women and 2.5% of men. Sexual initiation ≤15 years was more common among individuals aged 21–34 years (41.4% men and 33.6% women) as compared with older cohorts. Although having had ≥7 sexual partners over a lifetime among men was similar across age groups, this behavior decreased in older women cohorts. In both genders, the prevalence of oral and anal sex was also lower in the older age cohorts. Conclusion This study provides essential information than can help health professionals understand the sexual practices and needs of the population of PR. PMID:21676177

  5. Lung Cancer and Occupation in a Population-based Case-Control Study

    PubMed Central

    Consonni, Dario; De Matteis, Sara; Lubin, Jay H.; Wacholder, Sholom; Tucker, Margaret; Pesatori, Angela Cecilia; Caporaso, Neil E.; Bertazzi, Pier Alberto; Landi, Maria Teresa

    2010-01-01

    The authors examined the relation between occupation and lung cancer in the large, population-based Environment And Genetics in Lung cancer Etiology (EAGLE) case-control study. In 2002–2005 in the Lombardy region of northern Italy, 2,100 incident lung cancer cases and 2,120 randomly selected population controls were enrolled. Lifetime occupational histories (industry and job title) were coded by using standard international classifications and were translated into occupations known (list A) or suspected (list B) to be associated with lung cancer. Smoking-adjusted odds ratios and 95% confidence intervals were calculated with logistic regression. For men, an increased risk was found for list A (177 exposed cases and 100 controls; odds ratio = 1.74, 95% confidence interval: 1.27, 2.38) and most occupations therein. No overall excess was found for list B with the exception of filling station attendants and bus and truck drivers (men) and launderers and dry cleaners (women). The authors estimated that 4.9% (95% confidence interval: 2.0, 7.8) of lung cancers in men were attributable to occupation. Among those in other occupations, risk excesses were found for metal workers, barbers and hairdressers, and other motor vehicle drivers. These results indicate that past exposure to occupational carcinogens remains an important determinant of lung cancer occurrence. PMID:20047975

  6. Prevalence of different forms of child maltreatment among Taiwanese adolescents: a population-based study.

    PubMed

    Feng, Jui-Ying; Chang, Yi-Ting; Chang, Hsin-Yi; Fetzer, Susan; Wang, Jung-Der

    2015-04-01

    Reported cases of child maltreatment are increasing in Taiwan. Yet, comprehensive epidemiological characteristics of adolescents' exposure over the wide spectrum of violence are still lacking. The purpose of this study was to estimate the prevalence and magnitude of child maltreatment among Taiwanese adolescents. A population-based study was conducted with 5,276 adolescents aged 12-18 from 35 schools in 17 cities and townships to determine the prevalence of five forms of child maltreatment in Taiwan. A total of 5,236 adolescents completed anonymous, self-report, structured questionnaires. Most adolescents (91%, n=4,788) experienced at least one form of maltreatment with 83% (n=4,347) exposed during the previous year. Violence exposure was the most common type of child maltreatment experienced, followed by psychological abuse, physical abuse, neglect, and sexual abuse. Adolescents reported an average of 7.4 (SD=5.87) victimizations over their lifetime and 4.8 (SD=4.82) victimizations during the past year. Females reported a higher rate of neglect, while males reported a higher rate of sexual abuse. Most of the sexual abuse perpetrators were known by their victims. Adolescents' victimization and polyvictimization from child maltreatment in Taiwan deserves a review and modification of national control and prevention policies.

  7. Occupations and lung cancer: a population-based case-control study in British Columbia.

    PubMed

    Yenugadhati, Nagarajkumar; Birkett, Nicholas J; Momoli, Franco; Krewski, Daniel

    2009-01-01

    An investigation based on a large population-based case-control study in British Columbia, Canada, was conducted to identify high-risk occupations for lung cancer by histological subtypes. Subjects were 14,755 male incident cancer cases for whom lifetime occupational histories and information on smoking and relevant covariates were collected. Occupational associations for 2998 lung cancer cases, including histological subtypes, were assessed by logistic regression using other cancer cases, excluding smoking-related cancers, as controls. An excess risk of lung cancer was found among workers in metal processing, bakers, and ship deck crew for all histological subtypes, and construction workers, chefs and cooks, and medical workers for specific histological subtypes. Occupational associations that are unique to histological subtypes of lung cancer were identified. Owing to a scarcity of literature in this area, future research needs to focus on confirming these histological associations, and identifying the risk from key exposures found within these occupations (e.g., medical radiation, electromagnetic fields, and cooking fumes).

  8. Lung cancer and occupation in a population-based case-control study.

    PubMed

    Consonni, Dario; De Matteis, Sara; Lubin, Jay H; Wacholder, Sholom; Tucker, Margaret; Pesatori, Angela Cecilia; Caporaso, Neil E; Bertazzi, Pier Alberto; Landi, Maria Teresa

    2010-02-01

    The authors examined the relation between occupation and lung cancer in the large, population-based Environment And Genetics in Lung cancer Etiology (EAGLE) case-control study. In 2002-2005 in the Lombardy region of northern Italy, 2,100 incident lung cancer cases and 2,120 randomly selected population controls were enrolled. Lifetime occupational histories (industry and job title) were coded by using standard international classifications and were translated into occupations known (list A) or suspected (list B) to be associated with lung cancer. Smoking-adjusted odds ratios and 95% confidence intervals were calculated with logistic regression. For men, an increased risk was found for list A (177 exposed cases and 100 controls; odds ratio = 1.74, 95% confidence interval: 1.27, 2.38) and most occupations therein. No overall excess was found for list B with the exception of filling station attendants and bus and truck drivers (men) and launderers and dry cleaners (women). The authors estimated that 4.9% (95% confidence interval: 2.0, 7.8) of lung cancers in men were attributable to occupation. Among those in other occupations, risk excesses were found for metal workers, barbers and hairdressers, and other motor vehicle drivers. These results indicate that past exposure to occupational carcinogens remains an important determinant of lung cancer occurrence.

  9. Direct tests of muscle cross-bridge theories: predictions of a Brownian dumbbell model for position-dependent cross-bridge lifetimes and step sizes with an optically trapped actin filament.

    PubMed Central

    Smith, D A

    1998-01-01

    Force and displacement events from a single myosin molecule interacting with an actin filament suspended between optically trapped beads (Finer, J. T., R. M. Simmons, and J. A. Spudich. 1994. Nature. 368:113-119) can be interpreted in terms of a generalized cross-bridge model that includes the effects of Brownian forces on the beads. Steady-state distributions of force and displacement can be obtained directly from a generalized Smoluchowski equation for Brownian motion of the actin-bead "dumbbell," and time series from Monte Carlo simulations of the corresponding Langevin equation. When the frequency spectrum of Brownian motion extends beyond cross-bridge transition rates, the inverse mean lifetimes of force/displacement pulses are given by cross-bridge rate constants averaged over a Boltzmann distribution of Brownian noise. These averaged rate constants reflect the strain-dependence of the rate constants for the stationary filament, most faithfully at high trap stiffness. Hence, measurements of the lifetimes and displacements of single events as a function of the resting position of the dumbbell can provide a direct test of different cross-bridge theories of muscle contraction. Quantitative demonstrations are given for Huxley models with 1) faster binding or 2) slower dissociation at positive cross-bridge strain. Predictions for other models can be inferred from the averaging procedure. PMID:9826619

  10. Automated analysis of multimodal fluorescence lifetime imaging and optical coherence tomography data for the diagnosis of oral cancer in the hamster cheek pouch model.

    PubMed

    Pande, Paritosh; Shrestha, Sebina; Park, Jesung; Gimenez-Conti, Irma; Brandon, Jimi; Applegate, Brian E; Jo, Javier A

    2016-05-01

    It is known that the progression of oral cancer is accompanied by changes in both tissue biochemistry and morphology. A multimodal imaging approach combining functional and structural imaging modalities could therefore provide a more comprehensive prognosis of oral cancer. This idea forms the central theme of the current study, wherein this premise is examined in the context of a multimodal imaging system that combines fluorescence lifetime imaging (FLIM) and optical coherence tomography (OCT). Towards this end, in the first part of the present study, the diagnostic advantage obtained by using both fluorescence intensity and lifetime information is assessed. In the second part of the study, the diagnostic potential of FLIM-derived biochemical features is compared with that of OCT-derived morphological features. For an objective assessment, several quantitative biochemical and morphological features from FLIM and OCT data, respectively, were obtained using signal and image processing techniques. These features were subsequently used in a statistical classification framework to quantify the diagnostic potential of different features. The classification accuracy for combined FLIM and OCT features was estimated to be 87.4%, which was statistically higher than accuracy based on only FLIM (83.2%) or OCT (81.0%) features. Moreover, the complimentary information provided by FLIM and OCT features, resulted in highest sensitivity and specificity for the combined FLIM and OCT features for discriminating benign (88.2% sens., 92.0% spec.), pre-cancerous (81.5% sens., 96.0% spec.), and cancerous (90.1% sens., 92.0% spec.) classes.

  11. Automated analysis of multimodal fluorescence lifetime imaging and optical coherence tomography data for the diagnosis of oral cancer in the hamster cheek pouch model

    PubMed Central

    Pande, Paritosh; Shrestha, Sebina; Park, Jesung; Gimenez-Conti, Irma; Brandon, Jimi; Applegate, Brian E.; Jo, Javier A.

    2016-01-01

    It is known that the progression of oral cancer is accompanied by changes in both tissue biochemistry and morphology. A multimodal imaging approach combining functional and structural imaging modalities could therefore provide a more comprehensive prognosis of oral cancer. This idea forms the central theme of the current study, wherein this premise is examined in the context of a multimodal imaging system that combines fluorescence lifetime imaging (FLIM) and optical coherence tomography (OCT). Towards this end, in the first part of the present study, the diagnostic advantage obtained by using both fluorescence intensity and lifetime information is assessed. In the second part of the study, the diagnostic potential of FLIM-derived biochemical features is compared with that of OCT-derived morphological features. For an objective assessment, several quantitative biochemical and morphological features from FLIM and OCT data, respectively, were obtained using signal and image processing techniques. These features were subsequently used in a statistical classification framework to quantify the diagnostic potential of different features. The classification accuracy for combined FLIM and OCT features was estimated to be 87.4%, which was statistically higher than accuracy based on only FLIM (83.2%) or OCT (81.0%) features. Moreover, the complimentary information provided by FLIM and OCT features, resulted in highest sensitivity and specificity for the combined FLIM and OCT features for discriminating benign (88.2% sens., 92.0% spec.), pre-cancerous (81.5% sens., 96.0% spec.), and cancerous (90.1% sens., 92.0% spec.) classes. PMID:27231638

  12. Carrier lifetimes in silicon carbide

    NASA Astrophysics Data System (ADS)

    Nigam, Saurav

    Carrier lifetimes are one of the most crucial parameters that govern the performance of high voltage/high power devices. The lack of understanding of the factors that determine the carrier lifetimes in silicon carbide is currently a major impediment in the development of high voltage/high power technology based on this material. The objective of this dissertation was to identify and subsequently, characterize various recombination channels present in silicon carbide. Of special importance was identification of lifetime limiting defects in the high quality epitaxial layers grown by state-of-the-art chemical vapor deposition technique for high voltage application. The effect of growth conditions (C/Si ratio, growth temperature, seed polarity, epilayer thickness, and background doping) on the concentrations of various defects were investigated with the aim of manipulating carrier lifetimes by controlling different growth parameters. Based on the qualitative correlations between various point defects and carrier lifetimes in more than thirty epitaxial layers, three defects (Z-defect, EH6/7 center, and P1 center) were identified as potential lifetime limiting defects. The P1 center was shown to act as efficient recombination channel whenever present in concentrations greater than 1013 cm-3. Such concentrations were observed in layers grown on the C-face and at low C/Si ratio (less than 1.5). The measurement of recombination rates of electrons and holes via the Z-defect and the EH6/7 center (as a function of temperature) were performed by analyzing the carrier dynamics in specially designed p-n diodes. At 300 K, the capture cross section of the two states of the Z-defect were sigman1˜6x10-15 cm2 (electron capture at the donor state), sigmap1˜2x1014 cm2 (hole capture at the donor state), sigman2˜1x10 16 cm2 (electron capture at the acceptor state), and sigma p2˜1e-13 cm2 (hole capture at the acceptor state). The electron capture cross section for the EH6/7 centers was

  13. On the method of positron lifetime measurement

    NASA Technical Reports Server (NTRS)

    Nishiyama, F.; Shizuma, K.; Nasai, H.; Nishi, M.

    1983-01-01

    A fast-slow coincidence system was constructed for the measurement of positron lifetimes in material. The time resolution of this system was 270 ps for the (60)Co gamma rays. Positron lifetime spectra for 14 kinds of alkali halides were measured with this system. Two lifetime components and their intensities were derived from analyses of the lifetime spectra.

  14. Fluorescence lifetime in cardiovascular diagnostics

    NASA Astrophysics Data System (ADS)

    Marcu, Laura

    2010-01-01

    We review fluorescence lifetime techniques including time-resolved laser-induced fluorescence spectroscopy (TR-LIFS) and fluorescence lifetime imaging microscopy (FLIM) instrumentation and associated methodologies that allow for characterization and diagnosis of atherosclerotic plaques. Emphasis is placed on the translational research potential of TR-LIFS and FLIM and on determining whether intrinsic fluorescence signals can be used to provide useful contrast for the diagnosis of high-risk atherosclerotic plaque. Our results demonstrate that these techniques allow for the discrimination of important biochemical features involved in atherosclerotic plaque instability and rupture and show their potential for future intravascular applications.

  15. Habitable zone lifetimes of exoplanets around main sequence stars.

    PubMed

    Rushby, Andrew J; Claire, Mark W; Osborn, Hugh; Watson, Andrew J

    2013-09-01

    The potential habitability of newly discovered exoplanets is initially assessed by determining whether their orbits fall within the circumstellar habitable zone of their star. However, the habitable zone (HZ) is not static in time or space, and its boundaries migrate outward at a rate proportional to the increase in luminosity of a star undergoing stellar evolution, possibly including or excluding planets over the course of the star's main sequence lifetime. We describe the time that a planet spends within the HZ as its "habitable zone lifetime." The HZ lifetime of a planet has strong astrobiological implications and is especially important when considering the evolution of complex life, which is likely to require a longer residence time within the HZ. Here, we present results from a simple model built to investigate the evolution of the "classic" HZ over time, while also providing estimates for the evolution of stellar luminosity over time in order to develop a "hybrid" HZ model. These models return estimates for the HZ lifetimes of Earth and 7 confirmed HZ exoplanets and 27 unconfirmed Kepler candidates. The HZ lifetime for Earth ranges between 6.29 and 7.79×10⁹ years (Gyr). The 7 exoplanets fall in a range between ∼1 and 54.72 Gyr, while the 27 Kepler candidate planets' HZ lifetimes range between 0.43 and 18.8 Gyr. Our results show that exoplanet HD 85512b is no longer within the HZ, assuming it has an Earth analog atmosphere. The HZ lifetime should be considered in future models of planetary habitability as setting an upper limit on the lifetime of any potential exoplanetary biosphere, and also for identifying planets of high astrobiological potential for continued observational or modeling campaigns.

  16. National nephrectomy registries: Reviewing the need for population-based data.

    PubMed

    Pearson, John; Williamson, Timothy; Ischia, Joseph; Bolton, Damien M; Frydenberg, Mark; Lawrentschuk, Nathan

    2015-09-01

    Nephrectomy is the cornerstone therapy for renal cell carcinoma (RCC) and continued refinement of the procedure through research may enhance patient outcomes. A national nephrectomy registry may provide the key information needed to assess the procedure at a national level. The aim of this study was to review nephrectomy data available at a population-based level in Australia and to benchmark these data against data from the rest of the world as an examination of the national nephrectomy registry model. A PubMed search identified records pertaining to RCC nephrectomy in Australia. A similar search identified records relating to established nephrectomy registries internationally and other surgical registries of clinical importance. These records were reviewed to address the stated aims of this article. Population-based data within Australia for nephrectomy were lacking. Key issues identified were the difficulty in benchmarking outcomes and no ongoing monitoring of trends. The care centralization debate, which questions whether small-volume centers provide comparable outcomes to high-volume centers, is ongoing. Patterns of adherence and the effectiveness of existing protocols are uncertain. A review of established international registries demonstrated that the registry model can effectively address issues comparable to those identified in the Australian literature. A national nephrectomy registry could address deficiencies identified in a given nation's nephrectomy field. The model is supported by evidence from international examples and will provide the population-based data needed for studies. Scope exists for possible integration with other registries to develop a more encompassing urological or surgical registry. Need remains for further exploration of the feasibility and practicalities of initiating such a registry including a minimum data set, outcome indicators, and auditing of data.

  17. Key drivers of methane lifetime from 1860-2100

    NASA Astrophysics Data System (ADS)

    John, J. G.; Fiore, A. M.; Naik, V.; Horowitz, L. W.

    2011-12-01

    Atmospheric methane (CH4) is the most important anthropogenic greenhouse gas after carbon dioxide, and is a key component of atmospheric chemistry. Oxidation by the hydroxyl radical is the primary determinant of atmospheric methane lifetime. Hence, factors that regulate OH also drive changes in methane lifetime. We investigate the trends and key drivers of methane lifetime in a suite of historical (1860-2005) and Representative Concentration Pathway (RCP) simulations (2005-2100) conducted with the GFDL fully coupled chemistry-climate model (CM3) in support of the 5th coupled model intercomparison project (CMIP5/IPCC AR5). Over the historical period, the methane lifetime increases slightly (5%) from 1860-1879 to 1986-2005. We use additional sensitivity simulations over the historical period to separate the impacts on methane lifetime from short-lived climate forcing agents, well-mixed greenhouse gases, and aerosol-cloud interactions. In the RCP4.5 (moderate warming) future scenario, methane lifetime decreases by 13% from 2006-2025 to 2081-2100. Using a future simulation in which only well-mixed greenhouse gas emission are allowed to change (following the RCP4.5 scenario), we show that a warming climate leads to a shorter methane lifetime (by 5%) from the direct impact of temperature on the CH4+OH rate constant, as well as from enhanced OH associated with increased water vapor and lightning NOx. Changes in short-lived climate forcing agents in the full RCP4.5 scenario further reinforce the climate-driven changes. In contrast, the methane lifetime increases by 4% in the RCP8.5 scenario, despite the extreme warming (>4K below 500 hPa). In this simulation, we find that the large rise in CH4 abundance (approximate doubling) counteracts the tendency of rising temperature, water vapor, and lightning NOx and decreasing CO emissions to decrease methane lifetime.

  18. Final report on reliability and lifetime prediction.

    SciTech Connect

    Gillen, Kenneth T; Wise, Jonathan; Jones, Gary D.; Causa, Al G.; Terrill, Edward R.; Borowczak, Marc

    2012-12-01

    This document highlights the important results obtained from the subtask of the Goodyear CRADA devoted to better understanding reliability of tires and to developing better lifetime prediction methods. The overall objective was to establish the chemical and physical basis for the degradation of tires using standard as well as unique models and experimental techniques. Of particular interest was the potential application of our unique modulus profiling apparatus for assessing tire properties and for following tire degradation. During the course of this complex investigation, extensive relevant information was generated, including experimental results, data analyses and development of models and instruments. Detailed descriptions of the findings are included in this report.

  19. Population-based case-control association studies.

    PubMed

    Hancock, Dana B; Scott, William K

    2012-07-01

    This unit provides an overview of the design and analysis of population-based case-control studies of genetic risk factors for complex disease. Considerations specific to genetic studies are emphasized. The unit reviews basic study designs differentiating case-control studies from others, presents different genetic association strategies (candidate gene, genome-wide association, and high-throughput sequencing), introduces basic methods of statistical analysis for case-control data and approaches to combining case-control studies, and discusses measures of association and impact. Admixed populations, controlling for confounding (including population stratification), consideration of multiple loci and environmental risk factors, and complementary analyses of haplotypes, genes, and pathways are briefly discussed. Readers are referred to basic texts on epidemiology for more details on general conduct of case-control studies.

  20. Predictors of Childhood Anxiety: A Population-Based Cohort Study

    PubMed Central

    2015-01-01

    Background Few studies have explored predictors of early childhood anxiety. Objective To determine the prenatal, postnatal, and early life predictors of childhood anxiety by age 5. Methods Population-based, provincial administrative data (N = 19,316) from Manitoba, Canada were used to determine the association between demographic, obstetrical, psychosocial, medical, behavioral, and infant factors on childhood anxiety. Results Risk factors for childhood anxiety by age 5 included maternal psychological distress from birth to 12 months and 13 months to 5 years post-delivery and an infant 5-minute Apgar score of ≤7. Factors associated with decreased risk included maternal age < 20 years, multiparity, and preterm birth. Conclusion Identifying predictors of childhood anxiety is a key step to early detection and prevention. Maternal psychological distress is an early, modifiable risk factor. Future research should aim to disentangle early life influences on childhood anxiety occurring in the prenatal, postnatal, and early childhood periods. PMID:26158268

  1. The Work of a Lifetime

    ERIC Educational Resources Information Center

    Olson, Cathy Applefeld

    2012-01-01

    If there's one message that Joan Hillsman wants to get across to music directors, it's this: Teaching is a lifetime commitment. Hillsman is a longtime music educator, African-American music historian, author, consultant, music producer, clinician, radio show host, and current member of the Academic Board of the James Cleveland Gospel Music…

  2. Lifetime measurements in 162Dy

    NASA Astrophysics Data System (ADS)

    Aprahamian, A.; Lesher, S. R.; Casarella, C.; Börner, H. G.; Jentschel, M.

    2017-02-01

    Background: The nature of oscillations or excitations around the equilibrium deformed nuclear shape remains an open question in nuclear structure. The 162Dy nucleus is one of the most extensively studied nuclei with the (n ,γ ), (n ,e- ), (α ,2 n ) reactions and most recently the (p ,t ) pickup reaction adding 11 0+ states to an excitation energy of 2.8 MeV to an already-well-developed level scheme. However, a major shortfall for a better understanding of the nature of the plethora of bands and levels in this nucleus has been the lack of lifetime measurements. Purpose: To determine the character of the low-lying excited bands in this 162Dy nucleus, we set out to measure the level lifetimes. Method: Lifetimes were measured in the 162Dy nucleus following neutron capture using the Gamma-Ray-Induced Doppler (GRID) broadening technique at the Institut Laue-Langevin in Grenoble, France. Results: In total, we have measured the lifetimes of 12 levels belonging to a number of excited positive- and negative-parity bands in the low-lying spectrum of the 162Dy nucleus. The lifetime of the Kπ=2+ bandhead at 888.16 keV was previously measured. We confirm this value and measure lifetimes of the 3+ and 4+ members of this band yielding B (E 2 ) values that are consistent with a single γ -vibrational phonon of several Weisskopf units. The first excited Kπ=4+ band, with a bandhead at 1535.66 keV, is strongly connected to the Kπ=2+ band with enhanced collective B (E 2 ) values and it is consistent with a double phonon vibrational (γ γ ) excitation. Lifetime of Kπ=0+ band members have also been measured, including the 4Kπ=02+ state at 1574.29 keV and the 2Kπ= 03+ state at 1728.31 keV. This latter state also displays the characteristics of a double phonon excitation built on the Kπ=2+ band. Conclusions: We discuss our findings in terms of the presence or absence of collective quadrupole and octupole vibrational excitations. We find two positive-parity excited bands at 1535

  3. Lifetimes and Reliabilities of Bevel-Gear Drive Trains

    NASA Technical Reports Server (NTRS)

    Lewicki, D.; Cox, J.; Savage, M.; Brikmanis, C.

    1986-01-01

    Statistical methods used to predict system lifetimes from component lifetimes. Report shows how to use information to determine system life of drive train, using methods of probability and statistics. Presents life and reliability model for bevel-gear drive trains. Bevel-gear and support-bearing lives analyzed for each gear and bearing in drive train, with results statistically combined to produce system life for entire drive train. Numerical example included.

  4. Longitudinal population-based studies of affective disorders: Where to from here?

    PubMed Central

    Beard, John R; Galea, Sandro; Vlahov, David

    2008-01-01

    Background Longitudinal, population-based, research is important if we are to better characterize the lifetime patterns and determinants of affective disorders. While studies of this type are becoming increasingly prevalent, there has been little discussion about the limitations of the methods commonly used. Methods Discussion paper including a brief review of key prospective population-based studies as the basis for a critical appraisal of current approaches. Results We identified a number of common methodological weaknesses that restrict the potential of longitudinal research to characterize the diversity, prognosis, and determinants of affective disorders over time. Most studies using comprehensive diagnostic instruments have either been of relatively brief duration, or have suffered from long periods between waves. Most etiologic research has focused on first onset diagnoses, although these may be relatively uncommon after early adulthood and the burden of mental disorders falls more heavily on individuals with recurring disorders. Analysis has tended to be based on changes in diagnostic status rather than anges in symptom levels, limiting study power. Diagnoses have generally been treated as homogeneous entities and few studies have explored whether diagnostic subtypes such as atypical depression vary in their etiology or prognosis. Little research has considered whether there are distinct trajectories of symptoms over time and most has focused on individual disorders such as depression, rather than considering the relationship over time between symptoms of different affective disorders. There has also been limited longitudinal research on factors in the physical or social environment that may influence the onset, recurrence or chronicity of symptoms. Conclusion Many important, and in some respects quite basic, questions remain about the trajectory of depression and anxiety disorders over the life course and the factors that influence their incidence

  5. tomoFLIM - fluorescence lifetime projection tomography

    NASA Astrophysics Data System (ADS)

    McGinty, James; Stuckey, Daniel W.; Tahir, Khadija B.; Laine, Romain; Hajnal, Joseph V.; Sardini, Alessandro; French, Paul M. W.

    2010-02-01

    Optical Projection Tomography (OPT) is a wide-field technique for measuring the threedimensional distribution of absorbing/fluorescing species in non-scattering (optically cleared) samples up to ~1cm in size, and as such is the optical analogue of X-ray computed tomography. We have extended the intensity-based OPT technique to measure the three-dimensional fluorescence lifetime distribution (tomoFLIM) in transparent samples. Due to its inherent ratiometric nature, fluorescence lifetime measurements are robust against intensity-based artifacts as well as producing a quantitative measure of the fluorescence signal, making it particularly suited to Förster Resonance Energy Transfer (FRET) measurements. We implement tomoFLIM via OPT by acquiring a series of wide-field time-gated images at different relative time delays with respect to a train of excitation pulses for a range of projection angles. For each time delay, the three-dimensional time-gated intensity distribution is reconstructed using a filtered back projection algorithm and the fluorescence lifetime is subsequently determined for each reconstructed horizontal plane by iterative fitting of an appropriate decay model. We present a tomographic reconstruction of a fluorescence lifetime resolved FRET calcium contruct, TN-L15 cytosol suspension, in a silicone phantom. This genetically encoded sensor, TN-L15, comprises the calcium-binding domain of Troponin C, flanked by the fluorophores cyan fluorescent protein and citrine. In the presence of calcium ions TN-L15 changes conformation bringing the two fluorophores into close proximity, resulting in FRET. We also present autofluorescence and fluorescently labelled tomoFLIM reconstructions of chick embryos, including a genetically encoded fluorophore TagRFP-T. The fluorophore was electroporated in ovo into the neural tube of the embryos, which were subsequently dissected two days post-electroporation, fixed in ethanol and optically cleared for OPT

  6. A population-based exposure assessment methodology for carbon monoxide: Development of a carbon monoxide passive sampler and occupational dosimeter

    SciTech Connect

    Apte, Michael G.

    1997-09-01

    Two devices, an occupational carbon monoxide (CO) dosimeter (LOCD), and an indoor air quality (IAQ) passive sampler were developed for use in population-based CO exposure assessment studies. CO exposure is a serious public health problem in the U.S., causing both morbidity and mortality (lifetime mortality risk approximately 10{sup -4}). Sparse data from population-based CO exposure assessments indicate that approximately 10% of the U.S. population is exposed to CO above the national ambient air quality standard. No CO exposure measurement technology is presently available for affordable population-based CO exposure assessment studies. The LOCD and IAQ Passive Sampler were tested in the laboratory and field. The palladium-molybdenum based CO sensor was designed into a compact diffusion tube sampler that can be worn. Time-weighted-average (TWA) CO exposure of the device is quantified by a simple spectrophotometric measurement. The LOCD and IAQ Passive Sampler were tested over an exposure range of 40 to 700 ppm-hours and 200 to 4200 ppm-hours, respectively. Both devices were capable of measuring precisely (relative standard deviation <20%), with low bias (<10%). The LOCD was screened for interferences by temperature, humidity, and organic and inorganic gases. Temperature effects were small in the range of 10°C to 30°C. Humidity effects were low between 20% and 90% RH. Ethylene (200 ppm) caused a positive interference and nitric oxide (50 ppm) caused a negative response without the presence of CO but not with CO.

  7. Hybrid lipids increase nanoscale fluctuation lifetimes in mixed membranes

    NASA Astrophysics Data System (ADS)

    Palmieri, Benoit; Safran, Samuel A.

    2013-09-01

    A recently proposed ternary mixture model is used to predict fluctuation domain lifetimes in the one phase region. The membrane is made of saturated, unsaturated, and hybrid lipids that have one saturated and one unsaturated hydrocarbon chain. The hybrid lipid is a natural linactant which can reduce the packing incompatibility between saturated and unsaturated lipids. The fluctuation lifetimes are predicted as a function of the hybrid lipid fraction and the fluctuation domain size. These lifetimes can be increased by up to three orders of magnitude compared to the case of no hybrids. With hybrid, small length scale fluctuations have sizable amplitudes even close to the critical temperature and, hence, benefit from enhanced critical slowing down. The increase in lifetime is particularly important for nanometer scale fluctuation domains where the hybrid orientation and the other lipids composition are highly coupled.

  8. Hybrid lipids increase nanoscale fluctuation lifetimes in mixed membranes.

    PubMed

    Palmieri, Benoit; Safran, Samuel A

    2013-09-01

    A recently proposed ternary mixture model is used to predict fluctuation domain lifetimes in the one phase region. The membrane is made of saturated, unsaturated, and hybrid lipids that have one saturated and one unsaturated hydrocarbon chain. The hybrid lipid is a natural linactant which can reduce the packing incompatibility between saturated and unsaturated lipids. The fluctuation lifetimes are predicted as a function of the hybrid lipid fraction and the fluctuation domain size. These lifetimes can be increased by up to three orders of magnitude compared to the case of no hybrids. With hybrid, small length scale fluctuations have sizable amplitudes even close to the critical temperature and, hence, benefit from enhanced critical slowing down. The increase in lifetime is particularly important for nanometer scale fluctuation domains where the hybrid orientation and the other lipids composition are highly coupled.

  9. Estimating glomerular filtration rate in a population-based study

    PubMed Central

    Shankar, Anoop; Lee, Kristine E; Klein, Barbara EK; Muntner, Paul; Brazy, Peter C; Cruickshanks, Karen J; Nieto, F Javier; Danforth, Lorraine G; Schubert, Carla R; Tsai, Michael Y; Klein, Ronald

    2010-01-01

    Background: Glomerular filtration rate (GFR)-estimating equations are used to determine the prevalence of chronic kidney disease (CKD) in population-based studies. However, it has been suggested that since the commonly used GFR equations were originally developed from samples of patients with CKD, they underestimate GFR in healthy populations. Few studies have made side-by-side comparisons of the effect of various estimating equations on the prevalence estimates of CKD in a general population sample. Patients and methods: We examined a population-based sample comprising adults from Wisconsin (age, 43–86 years; 56% women). We compared the prevalence of CKD, defined as a GFR of <60 mL/min per 1.73 m2 estimated from serum creatinine, by applying various commonly used equations including the modification of diet in renal disease (MDRD) equation, Cockcroft–Gault (CG) equation, and the Mayo equation. We compared the performance of these equations against the CKD definition of cystatin C >1.23 mg/L. Results: We found that the prevalence of CKD varied widely among different GFR equations. Although the prevalence of CKD was 17.2% with the MDRD equation and 16.5% with the CG equation, it was only 4.8% with the Mayo equation. Only 24% of those identified to have GFR in the range of 50–59 mL/min per 1.73 m2 by the MDRD equation had cystatin C levels >1.23 mg/L; their mean cystatin C level was only 1 mg/L (interquartile range, 0.9–1.2 mg/L). This finding was similar for the CG equation. For the Mayo equation, 62.8% of those patients with GFR in the range of 50–59 mL/min per 1.73 m2 had cystatin C levels >1.23 mg/L; their mean cystatin C level was 1.3 mg/L (interquartile range, 1.2–1.5 mg/L). The MDRD and CG equations showed a false-positive rate of >10%. Discussion: We found that the MDRD and CG equations, the current standard to estimate GFR, appeared to overestimate the prevalence of CKD in a general population sample. PMID:20730018

  10. Population-based prevention of influenza in Dutch general practice.

    PubMed Central

    Hak, E; Hermens, R P; van Essen, G A; Kuyvenhoven, M M; de Melker, R A

    1997-01-01

    BACKGROUND: Although the effectiveness of influenza vaccination in high-risk groups has been proven, vaccine coverage continues to be less than 50% in The Netherlands. To improve vaccination rates, data on the organizational factors, which should be targeted in population-based prevention of influenza, is essential. AIM: To assess the organizational factors in Dutch general practice, which were associated with the influenza vaccination rate in 1994. METHOD: A retrospective questionnaire study was undertaken in 1586 of the 4758 Dutch general practices, which were randomly selected. A total of 1251 (79%) practices returned a questionnaire. The items verified were practice profile, urbanization, delegation index, use of computer-based patient records, influenza vaccination characteristics and influenza vaccination rate. RESULTS: No differences were found with regard to the percentage of single-handed practices (65%), practices situated in urban area (38%), practices with a pharmacy (12%), patients insured by the National Health Service (59%) and use of computer-based patient records (57%) when compared with national statistics. The mean overall influenza vaccination rate was 9.0% (SD 4.0%). Using a logistic regression analysis, a high vaccination rate (> or = 9%) was associated with the use of personal reminders (odds ratio (OR) 1.7, 1.3-2.2), monitoring patient compliance (OR 1.8, 1.3-2.4), marking risk patients in computer-based patient records (OR 1.3, 1.0-1.6), a small number of patients per full-time practice assistant (OR 1.5, 1.1-1.9), urban areas (OR 1.6, 1.3-2.1) and single-handed practices (OR 1.5, 1.1-1.9). CONCLUSION: Improvement of vaccination rates in high-risk patients may be achievable by promoting the use of personal reminders and computer-based patient records, as well as monitoring patient compliance. In addition, the role of practice assistants with regard to preventive activities should be developed further. Practices situated in rural areas and

  11. Measurement and Perturbation of Morphogen Lifetime: Effects on Gradient Shape

    PubMed Central

    Drocco, Jeffrey A.; Grimm, Oliver; Tank, David W.; Wieschaus, Eric

    2011-01-01

    Protein lifetime is of critical importance for most biological processes and plays a central role in cell signaling and embryonic development, where it impacts the absolute concentration of signaling molecules and, potentially, the shape of morphogen gradients. Early conceptual and mathematical models of gradient formation proposed that steady-state gradients are established by an equilibration between the lifetime of a morphogen and its rates of synthesis and diffusion, though whether gradients in fact reach steady state before being read out is a matter of controversy. In any case, this class of models predicts that protein lifetime is a key determinant of both the time to steady state and the spatial extent of a gradient. Using a method that employs repeated photoswitching of a fusion of the morphogen Bicoid (Bcd) and the photoconvertible fluorescent protein Dronpa, we measure and modify the lifetime of Dronpa-Bcd in living Drosophila embryos. We find that the lifetime of Bcd is dynamic, changing from 50 min before mitotic cycle 14 to 15 min during cellularization. Moreover, by measuring total quantities of Bcd over time, we find that the gradient does not reach steady state. Finally, using a nearly continuous low-level conversion to the dark state of Dronpa-Bcd to mimic the effect of increased degradation, we demonstrate that perturbation of protein lifetime changes the characteristic length of the gradient, providing direct support for a mechanism based on synthesis, diffusion, and degradation. PMID:22004733

  12. Lifetime of MCP-PMTs

    NASA Astrophysics Data System (ADS)

    Lehmann, A.; Britting, A.; Eyrich, W.; Pfaffinger, M.; Uhlig, F.; Belias, A.; Dzhygadlo, R.; Gerhardt, A.; Götzen, K.; Kalicy, G.; Krebs, M.; Lehmann, D.; Nerling, F.; Patsyuk, M.; Peters, K.; Schepers, G.; Schmitt, L.; Schwarz, C.; Schwiening, J.; Traxler, M.; Zühlsdorf, M.; Düren, M.; Etzelmüller, E.; Föhl, K.; Hayrapetyan, A.; Kröck, B.; Merle, O.; Rieke, J.; Schmidt, M.; Cowie, E.; Keri, T.; Achenbach, P.; Cardinali, M.; Hoek, M.; Lauth, W.; Schlimme, S.; Sfienti, C.; Thiel, M.

    2016-05-01

    The hadron identification in the PANDA experiment at FAIR will be done with DIRC detectors. Because of design and space reasons the sensors of the DIRCs have to be placed inside the strong magnetic field of the solenoid. As the favored photon sensors microchannel-plate photomultipliers (MCP-PMTs) were identified. However, these devices showed serious aging problems until very recently, which manifest themselves by a fast degrading quantum efficiency (QE) of the photo cathode (PC). This is mainly due to feedback ions from the residual gas. In this paper we discuss the recently accomplished huge improvements in the lifetime of MCP-PMTs. With innovative countermeasures applied to the MCP-PMTs in the attempt to reduce the aging effects the manufacturers were able to increase the lifetime of MCP-PMT prototypes by almost two orders of magnitude compared to the former commercially available devices. Our group has studied the aging of MCP-PMTs for more than four years by simultaneously illuminating different types of lifetime-enhanced MCP-PMTs at the same photon rate. Gain, dark count rate, and QE as a function of the wavelength and the PC surface were measured in regular time intervals and studied in dependence of the integrated anode charge. We observe that MCP-PMTs treated with an atomic layer deposition (ALD) technique are by far the best devices available now. A lifetime of up to 10 C/cm2 integrated anode charge was reached with these sensors. This is sufficient for both PANDA DIRCs.

  13. Provider communication on perinatal depression: a population-based study.

    PubMed

    Farr, Sherry L; Ko, Jean Y; Burley, Kim; Gupta, Seema

    2016-02-01

    Women's lack of knowledge on symptoms of perinatal depression and treatment resources is a barrier to receiving care. We sought to estimate the prevalence and predictors of discussing depression with a prenatal care provider. We used the 2011 population-based data from 24 sites participating in the Pregnancy Risk Assessment Monitoring System (n = 32,827 women with recent live births) to examine associations between maternal characteristics and report that a prenatal care provider discussed with her what to do if feeling depressed during or after pregnancy. Overall, 71.9 % of women reported discussing perinatal depression with their prenatal care provider (range 60.7 % in New York City to 85.6 % in Maine). Women were more likely to report a discussion on perinatal depression with their provider if they they were 18-29 years of age than over 35 years of age compared to older (adjusted prevalence ratio [aPR] 18 to 19 y = 1.08, 20 to 24 y = 1.10, 25 to 29 y = 1.09), unmarried (aPR = 1.07) compared to married, had <12 years of education (aPR = 1.05) compared to > 12 years, and had no previous live births (aPR = 1.03) compared to ≥ 1 live births. Research is needed on effective ways to educate women about perinatal depression and whether increased knowledge on perinatal depression results in higher rates of treatment and shorter duration of symptoms.

  14. Psoriasis and dyslipidaemia: a population-based study.

    PubMed

    Dreiher, Jacob; Weitzman, Dahlia; Davidovici, Batya; Shapiro, Jonathan; Cohen, Arnon D

    2008-01-01

    Previous reports demonstrated an association between psoriasis and the metabolic syndrome. The aim of this study was to elucidate the association between psoriasis and dyslipidaemia. A cross-sectional study was performed utilizing a population-based database. Psoriasis patients were compared with enrollees without psoriasis regarding the prevalence of dyslipidaemia and lipid levels. Comparison of lipid levels was performed on a "low-risk" subset of subjects without diabetes, hypertension and cardiovascular disease. The study included 10,669 psoriasis patients and 22,996 subjects without psoriasis. The prevalence of dyslipidaemia was significantly higher in psoriasis patients (odds ratio (OR) = 1.48, 95% confidence interval (CI) 1.40-1.55). The association remained significant after controlling for confounders (OR = 1.19, 95% CI 1.12-1.26, p < 0.001). In multivariate analysis of the "low-risk" subset, triglyceride levels were higher in psoriasis patients and high-density lipoprotein cholesterol levels were lower. This study supports previous reports of an association between psoriasis and lipid abnormalities.

  15. Optimal inverse functions created via population-based optimization.

    PubMed

    Jennings, Alan L; Ordóñez, Raúl

    2014-06-01

    Finding optimal inputs for a multiple-input, single-output system is taxing for a system operator. Population-based optimization is used to create sets of functions that produce a locally optimal input based on a desired output. An operator or higher level planner could use one of the functions in real time. For the optimization, each agent in the population uses the cost and output gradients to take steps lowering the cost while maintaining their current output. When an agent reaches an optimal input for its current output, additional agents are generated in the output gradient directions. The new agents then settle to the local optima for the new output values. The set of associated optimal points forms an inverse function, via spline interpolation, from a desired output to an optimal input. In this manner, multiple locally optimal functions can be created. These functions are naturally clustered in input and output spaces allowing for a continuous inverse function. The operator selects the best cluster over the anticipated range of desired outputs and adjusts the set point (desired output) while maintaining optimality. This reduces the demand from controlling multiple inputs, to controlling a single set point with no loss in performance. Results are demonstrated on a sample set of functions and on a robot control problem.

  16. Stress and dysmenorrhoea: a population based prospective study

    PubMed Central

    Wang, L; Wang, X; Wang, W; Chen, C; Ronnennberg, A; Guang, W; Huang, A; Fang, Z; Zang, T; Wang, L; Xu, X

    2004-01-01

    Background: Dysmenorrhoea is the most common gynaecological disorder in women of reproductive age. Despite the association between stress and pregnancy outcomes, few studies have examined the possible link between stress and dysmenorrhoea. Aims and Methods: Using a population based cohort of Chinese women, the independent effect of women's perceived stress in the preceding menstrual cycle on the incidence of dysmenorrhoea in the subsequent cycle was investigated prospectively. The analysis included 1160 prospectively observed menstrual cycles from 388 healthy, nulliparous, newly married women who intended to conceive. The perception of stress and the occurrence of dysmenorrhoea in each menstrual cycle were determined from daily diaries recorded by the women. Results: After adjustment for important covariates, the risk of dysmenorrhoea was more than twice as great among women with high stress compared to those with low stress in the preceding cycle (OR = 2.4; 95% CI 1.4 to 4.3). The risk of dysmenorrhoea was greatest among women with both high stress and a history of dysmenorrhoea compared to women with low stress and no history of dysmenorrhoea (OR = 10.4, 95% CI 4.9 to 22.3). Stress in the follicular phase of the preceding cycles had a stronger association with dysmenorrhoea than stress in the luteal phase of the preceding cycles. Conclusion: This study shows a significant association between stress and the incidence of dysmenorrhoea, which is even stronger among women with a history of dysmenorrhoea. PMID:15550609

  17. Unbiased methods for population-based association studies.

    PubMed

    Devlin, B; Roeder, K; Bacanu, S A

    2001-12-01

    Large, population-based samples and large-scale genotyping are being used to evaluate disease/gene associations. A substantial drawback to such samples is the fact that population substructure can induce spurious associations between genes and disease. We review two methods, called genomic control (GC) and structured association (SA), that obviate many of the concerns about population substructure by using the features of the genomes present in the sample to correct for stratification. The GC approach exploits the fact that population substructure generates "over dispersion" of statistics used to assess association. By testing multiple polymorphisms throughout the genome, only some of which are pertinent to the disease of interest, the degree of overdispersion generated by population substructure can be estimated and taken into account. The SA approach assumes that the sampled population, although heterogeneous, is composed of subpopulations that are themselves homogeneous. By using multiple polymorphisms throughout the genome, this "latent class method" estimates the probability sampled individuals derive from each of these latent subpopulations. GC has the advantage of robustness, simplicity, and wide applicability, even to experimental designs such as DNA pooling. SA is a bit more complicated but has the advantage of greater power in some realistic settings, such as admixed populations or when association varies widely across subpopulations. It, too, is widely applicable. Both also have weaknesses, as elaborated in our review.

  18. Central poststroke pain: a population-based study.

    PubMed

    Klit, Henriette; Finnerup, Nanna Brix; Andersen, Grethe; Jensen, Troels Staehelin

    2011-04-01

    Central poststroke pain (CPSP) is a specific pain condition arising as a direct consequence of a cerebrovascular lesion. There is limited knowledge about the epidemiology and clinical characteristics of this often neglected but important consequence of stroke. In this population-based study, a questionnaire was sent out to all (n=964) stroke patients identified through the Danish National Indicator Project Stroke Database in Aarhus County, Denmark, between March 2004 and February 2005. All surviving patients who fulfilled 4 questionnaire criteria for possible CPSP (n=51) were selected for further clinical examination, and their pain was classified by using stringent and well-defined criteria and a detailed, standardized clinical examination. The minimum prevalence of definite or probable CPSP in this population is 7.3% and the prevalence of CPSP-like dysesthesia or pain is 8.6%. Pinprick hyperalgesia was present in 57%, cold allodynia in 40%, and brush-evoked dysesthesia in 51% of patients with CPSP. Because of its negative impact on quality of life and rehabilitation, pain is an important symptom to assess in stroke survivors.

  19. Heritability of Autism Spectrum Disorder in a UK Population-Based Twin Sample

    PubMed Central

    Colvert, Emma; Tick, Beata; McEwen, Fiona; Stewart, Catherine; Curran, Sarah R.; Woodhouse, Emma; Gillan, Nicola; Hallett, Victoria; Lietz, Stephanie; Garnett, Tracy; Ronald, Angelica; Plomin, Robert; Rijsdijk, Frühling; Happé, Francesca; Bolton, Patrick

    2016-01-01

    IMPORTANCE Most evidence to date highlights the importance of genetic influences on the liability to autism and related traits. However, most of these findings are derived from clinically ascertained samples, possibly missing individuals with subtler manifestations, and obtained estimates may not be representative of the population. OBJECTIVES To establish the relative contributions of genetic and environmental factors in liability to autism spectrum disorder (ASD) and a broader autism phenotype in a large population-based twin sample and to ascertain the genetic/environmental relationship between dimensional trait measures and categorical diagnostic constructs of ASD. DESIGN, SETTING, AND PARTICIPANTS We used data from the population-based cohort Twins Early Development Study, which included all twin pairs born in England and Wales from January 1, 1994, through December 31, 1996. We performed joint continuous-ordinal liability threshold model fitting using the full information maximum likelihood method to estimate genetic and environmental parameters of covariance. Twin pairs underwent the following assessments: the Childhood Autism Spectrum Test (CAST) (6423 pairs; mean age, 7.9 years), the Development and Well-being Assessment (DAWBA) (359 pairs; mean age, 10.3 years), the Autism Diagnostic Observation Schedule (ADOS) (203 pairs; mean age, 13.2 years), the Autism Diagnostic Interview–Revised (ADI-R) (205 pairs; mean age, 13.2 years), and a best-estimate diagnosis (207 pairs). MAIN OUTCOMES AND MEASURES Participants underwent screening using a population-based measure of autistic traits (CAST assessment), structured diagnostic assessments (DAWBA, ADI-R, and ADOS), and a best-estimate diagnosis. RESULTS On all ASD measures, correlations among monozygotic twins (range, 0.77-0.99) were significantly higher than those for dizygotic twins (range, 0.22-0.65), giving heritability estimates of 56% to 95%. The covariance of CAST and ASD diagnostic status (DAWBA, ADOS

  20. Lifetime Assessment of the NEXT Ion Thruster

    NASA Technical Reports Server (NTRS)

    VanNoord, Jonathan L.

    2010-01-01

    Ion thrusters are low thrust, high specific impulse devices with required operational lifetimes on the order of 10,000 to 100,000 hr. The NEXT ion thruster is the latest generation of ion thrusters under development. The NEXT ion thruster currently has a qualification level propellant throughput requirement of 450 kg of xenon, which corresponds to roughly 22,000 hr of operation at the highest throttling point. Currently, a NEXT engineering model ion thruster with prototype model ion optics is undergoing a long duration test to determine wear characteristics and establish propellant throughput capability. The NEXT thruster includes many improvements over previous generations of ion thrusters, but two of its component improvements have a larger effect on thruster lifetime. These include the ion optics with tighter tolerances, a masked region and better gap control, and the discharge cathode keeper material change to graphite. Data from the NEXT 2000 hr wear test, the NEXT long duration test, and further analysis is used to determine the expected lifetime of the NEXT ion thruster. This paper will review the predictions for all of the anticipated failure mechanisms. The mechanisms will include wear of the ion optics and cathode s orifice plate and keeper from the plasma, depletion of low work function material in each cathode s insert, and spalling of material in the discharge chamber leading to arcing. Based on the analysis of the NEXT ion thruster, the first failure mode for operation above a specific impulse of 2000 sec is expected to be the structural failure of the ion optics at 750 kg of propellant throughput, 1.7 times the qualification requirement. An assessment based on mission analyses for operation below a specific impulse of 2000 sec indicates that the NEXT thruster is capable of double the propellant throughput required by these missions.

  1. Lifetime Risks of Cardiovascular Disease

    PubMed Central

    Berry, Jarett D.; Dyer, Alan; Cai, Xuan; Garside, Daniel B.; Ning, Hongyan; Thomas, Avis; Greenland, Philip; Van Horn, Linda; Tracy, Russell P.; Lloyd-Jones, Donald M.

    2012-01-01

    BACKGROUND The lifetime risks of cardiovascular disease have not been reported across the age spectrum in black adults and white adults. METHODS We conducted a meta-analysis at the individual level using data from 18 cohort studies involving a total of 257,384 black men and women and white men and women whose risk factors for cardiovascular disease were measured at the ages of 45, 55, 65, and 75 years. Blood pressure, cholesterol level, smoking status, and diabetes status were used to stratify participants according to risk factors into five mutually exclusive categories. The remaining lifetime risks of cardiovascular events were estimated for participants in each category at each age, with death free of cardiovascular disease treated as a competing event. RESULTS We observed marked differences in the lifetime risks of cardiovascular disease across risk-factor strata. Among participants who were 55 years of age, those with an optimal risk-factor profile (total cholesterol level, <180 mg per deciliter [4.7 mmol per liter]; blood pressure, <120 mm Hg systolic and 80 mm Hg diastolic; nonsmoking status; and nondiabetic status) had substantially lower risks of death from cardiovascular disease through the age of 80 years than participants with two or more major risk factors (4.7% vs. 29.6% among men, 6.4% vs. 20.5% among women). Those with an optimal risk-factor profile also had lower lifetime risks of fatal coronary heart disease or nonfatal myocardial infarction (3.6% vs. 37.5% among men, <1% vs. 18.3% among women) and fatal or nonfatal stroke (2.3% vs. 8.3% among men, 5.3% vs. 10.7% among women). Similar trends within risk-factor strata were observed among blacks and whites and across diverse birth cohorts. CONCLUSIONS Differences in risk-factor burden translate into marked differences in the lifetime risk of cardiovascular disease, and these differences are consistent across race and birth cohorts. (Funded by the National Heart, Lung, and Blood Institute.) PMID

  2. The Prevalence and Causes of Primary Infertility in Iran: A Population-Based Study

    PubMed Central

    Kazemijaliseh, Hadigheh; Tehrani, Fahimeh Ramezani; Behboudi-Gandevani, Samira; Hosseinpanah, Farhad; Khalili, Davood; Azizi, Fereidoun

    2015-01-01

    Background: Primary infertility is a health issue among women over the world. The aim of this study was to investigate the prevalence and causes of primary infertility based on a population-based study in an urban area of Iran. Materials and Methods: In a cross-sectional study, a total of 1067 married women who participated in the Tehran Lipid and Glucose Study were randomly selected using systematic random sampling. Unmarried women, those with unwilling pregnancy and duration of marriage below one year were excluded from the study. Data was collected by using validated ad-hoc questionnaires. Descriptive and inferential statistics were used for data analysis. Results: The mean (SD) of age and marriage age of the studied women were 40.3 (9.3) and 20.6 (4.49) years, respectively; the overall prevalence of lifetime primary infertility among couples was 17.3% (185/1067). Ovulatory disorder (39.7%) and male factors (29.1%) were the main causes of primary infertility. In addition, 31 (17%) of the women were diagnosed with more than one cause. According to the logistic regression analysis, primary infertility was independently related to the old age of women (OR: 1.37; 95% CI: 1.14–13.63, P.value: 0.001), higher BMI (OR: 1.95; 95% CI: 1.87–4.14, P.value: 0.003), active smoking (OR: 1.47; 95% CI: 1.38–3.53, P.value: 0.012) and higher educational level (OR: 2.23; 95% CI: 1.12–5.53, P.value: 0.03). Conclusion: The prevalence of primary infertility in Iran was higher than the worldwide trends of infertility, indicating that understanding such risks help healthcare providers and policy makers to design and implement interventions to slow down this trend. PMID:26153187

  3. Minority carrier lifetime in indium phosphide

    NASA Technical Reports Server (NTRS)

    Jenkins, Phillip; Landis, Geoffrey A.; Weinberg, Irving; Kneisel, Keith

    1991-01-01

    Transient photoluminescence is used to measure the minority carrier lifetime on n-type and p-type InP wafers. The measurements show that unprocessed InP wafers have very high minority carrier lifetimes. Lifetimes of 200 ns and 700 ns were observed for lightly-doped p- and n-type material respectively. Lifetimes over 5 ns were found in heavily doped n-type material.

  4. Genotypic-specific variance in Caenorhabditis elegans lifetime fecundity

    PubMed Central

    Diaz, S Anaid; Viney, Mark

    2014-01-01

    Organisms live in heterogeneous environments, so strategies that maximze fitness in such environments will evolve. Variation in traits is important because it is the raw material on which natural selection acts during evolution. Phenotypic variation is usually thought to be due to genetic variation and/or environmentally induced effects. Therefore, genetically identical individuals in a constant environment should have invariant traits. Clearly, genetically identical individuals do differ phenotypically, usually thought to be due to stochastic processes. It is now becoming clear, especially from studies of unicellular species, that phenotypic variance among genetically identical individuals in a constant environment can be genetically controlled and that therefore, in principle, this can be subject to selection. However, there has been little investigation of these phenomena in multicellular species. Here, we have studied the mean lifetime fecundity (thus a trait likely to be relevant to reproductive success), and variance in lifetime fecundity, in recently-wild isolates of the model nematode Caenorhabditis elegans. We found that these genotypes differed in their variance in lifetime fecundity: some had high variance in fecundity, others very low variance. We find that this variance in lifetime fecundity was negatively related to the mean lifetime fecundity of the lines, and that the variance of the lines was positively correlated between environments. We suggest that the variance in lifetime fecundity may be a bet-hedging strategy used by this species. PMID:25360248

  5. Statin Use Reduces Prostate Cancer All-Cause Mortality: A Nationwide Population-Based Cohort Study.

    PubMed

    Sun, Li-Min; Lin, Ming-Chia; Lin, Cheng-Li; Chang, Shih-Ni; Liang, Ji-An; Lin, I-Ching; Kao, Chia-Hung

    2015-09-01

    Studies have suggested that statin use is related to cancer risk and prostate cancer mortality. We conducted a population-based cohort study to determine whether using statins in prostate cancer patients is associated with reduced all-cause mortality rates. Data were obtained from the Taiwan National Health Insurance Research Database. The study cohort comprised 5179 patients diagnosed with prostate cancer who used statins for at least 6 months between January 1, 1998 and December 31, 2010. To form a comparison group, each patient was randomly frequency-matched (according to age and index date) with a prostate cancer patient who did not use any type of statin-based drugs during the study period. The study endpoint was mortality. The hazard ratio (HR) and 95% confidence interval (CI) were estimated using Cox regression models. Among prostate cancer patients, statin use was associated with significantly decreased all-cause mortality (adjusted HR = 0.65; 95% CI = 0.60-0.71). This phenomenon was observed among various types of statin, age groups, and treatment methods. Analyzing the defined daily dose of statins indicated that both low- and high-dose groups exhibited significantly decreased death rates compared with nonusers, suggesting a dose-response relationship. The results of this population-based cohort study suggest that using statins reduces all-cause mortality among prostate cancer patients, and a dose-response relationship may exist.

  6. On estimation of time-dependent attributable fraction from population-based case-control studies.

    PubMed

    Zhao, Wei; Chen, Ying Qing; Hsu, Li

    2017-01-18

    Population attributable fraction (PAF) is widely used to quantify the disease burden associated with a modifiable exposure in a population. It has been extended to a time-varying measure that provides additional information on when and how the exposure's impact varies over time for cohort studies. However, there is no estimation procedure for PAF using data that are collected from population-based case-control studies, which, because of time and cost efficiency, are commonly used for studying genetic and environmental risk factors of disease incidences. In this article, we show that time-varying PAF is identifiable from a case-control study and develop a novel estimator of PAF. Our estimator combines odds ratio estimates from logistic regression models and density estimates of the risk factor distribution conditional on failure times in cases from a kernel smoother. The proposed estimator is shown to be consistent and asymptotically normal with asymptotic variance that can be estimated empirically from the data. Simulation studies demonstrate that the proposed estimator performs well in finite sample sizes. Finally, the method is illustrated by a population-based case-control study of colorectal cancer.

  7. Estimating lifetime healthcare costs with morbidity data

    PubMed Central

    2013-01-01

    Background In many developed countries, the economic crisis started in 2008 producing a serious contraction of the financial resources spent on healthcare. Identifying which individuals will require more resources and the moment in their lives these resources have to be allocated becomes essential. It is well known that a small number of individuals with complex healthcare needs consume a high percentage of health expenditures. Conversely, little is known on how morbidity evolves throughout life. The aim of this study is to introduce a longitudinal perspective to chronic disease management. Methods Data used relate to the population of the county of Baix Empordà in Catalonia for the period 2004–2007 (average population was N = 88,858). The database included individual information on morbidity, resource consumption, costs and activity records. The population was classified using the Clinical Risk Groups (CRG) model. Future morbidity evolution was simulated under different assumptions using a stationary Markov chain. We obtained morbidity patterns for the lifetime and the distribution function of the random variable lifetime costs. Individual information on acute episodes, chronic conditions and multimorbidity patterns were included in the model. Results The probability of having a specific health status in the future (healthy, acute process or different combinations of chronic illness) and the distribution function of healthcare costs for the individual lifetime were obtained for the sample population. The mean lifetime cost for women was €111,936, a third higher than for men, at €81,566 (all amounts calculated in 2007 Euros). Healthy life expectancy at birth for females was 46.99, lower than for males (50.22). Females also spent 28.41 years of life suffering from some type of chronic disease, a longer period than men (21.9). Conclusions Future morbidity and whole population costs can be reasonably predicted, combining stochastic microsimulation with a

  8. Probabilistic Prediction of Lifetimes of Ceramic Parts

    NASA Technical Reports Server (NTRS)

    Nemeth, Noel N.; Gyekenyesi, John P.; Jadaan, Osama M.; Palfi, Tamas; Powers, Lynn; Reh, Stefan; Baker, Eric H.

    2006-01-01

    ANSYS/CARES/PDS is a software system that combines the ANSYS Probabilistic Design System (PDS) software with a modified version of the Ceramics Analysis and Reliability Evaluation of Structures Life (CARES/Life) Version 6.0 software. [A prior version of CARES/Life was reported in Program for Evaluation of Reliability of Ceramic Parts (LEW-16018), NASA Tech Briefs, Vol. 20, No. 3 (March 1996), page 28.] CARES/Life models effects of stochastic strength, slow crack growth, and stress distribution on the overall reliability of a ceramic component. The essence of the enhancement in CARES/Life 6.0 is the capability to predict the probability of failure using results from transient finite-element analysis. ANSYS PDS models the effects of uncertainty in material properties, dimensions, and loading on the stress distribution and deformation. ANSYS/CARES/PDS accounts for the effects of probabilistic strength, probabilistic loads, probabilistic material properties, and probabilistic tolerances on the lifetime and reliability of the component. Even failure probability becomes a stochastic quantity that can be tracked as a response variable. ANSYS/CARES/PDS enables tracking of all stochastic quantities in the design space, thereby enabling more precise probabilistic prediction of lifetimes of ceramic components.

  9. Medullary carcinoma of the large intestine: a population based analysis.

    PubMed

    Thirunavukarasu, Pragatheeshwar; Sathaiah, Magesh; Singla, Smit; Sukumar, Shyam; Karunamurthy, Arivarasan; Pragatheeshwar, Kothai Divya; Lee, Kenneth K W; Zeh, Herbert; Kane, Kevin M; Bartlett, David L

    2010-10-01

    Medullary carcinoma (MC) of the colorectum is a relatively new histological type of adenocarcinoma characterized by poor glandular differentiation and intraepithelial lymphocytic infiltrate. To date, there has been no epidemiological study of this rare tumor type, which has now been incorporated as a separate entity in the World Health Organization (WHO) classification of colorectal cancers. We used the population-based registries of the Surveillance, Epidemiology and End Results (SEER) database to identify all cases of colorectal MC between 1973 and 2006 and compared them to poorly and undifferentiated colonic adenocarcinomas (PDA and UDA, respectively). We observed that MCs were rare tumors, constituting approximately 5-8 cases for every 10,000 colon cancers diagnosed, with a mean annual incidence of 3.47 (+/-0.75) per 10 million population. Mean age at diagnosis was 69.3 (+/-12.5) years, with incidence increasing with age. MCs were twice as common in females, who presented at a later age, with a lower stage and a trend towards favorable prognosis. MCs were extremely rare among African-Americans. MCs were most common in the proximal colon (74%), where they present at a later age than the sigmoid colon. There were no cases reliably identified in the rectum or appendix. Serum carcinoembryonic antigen levels (CEA) were elevated prior to first course of treatment in 40% of the patients. MCs were more commonly poorly differentiated (72%), with 22% being undifferentiated. MCs commonly presented with Stage II disease, with 10% presenting with metastases. Only one patient presented with N2b disease (>7 positive nodes). Early outcome analyses showed that MCs have 1- and 2-year relative survival rates of 92.7 and 73.8% respectively. Although MCs showed a trend towards better early overall survival, undifferentiated MCs present more commonly with Stage III, with comparatively worse early outcomes.

  10. Recurrence of hyperemesis gravidarum across generations: population based cohort study

    PubMed Central

    Skjærven, Rolv; Grjibovski, Andrej M; Gunnes, Nina; Vangen, Siri; Magnus, Per

    2010-01-01

    Objective To estimate the risk of hyperemesis gravidarum (hyperemesis) according to whether the daughters and sons under study were born after pregnancies complicated by hyperemesis. Design Population based cohort study. Setting Registry data from Norway. Participants Linked generational data from the medical birth registry of Norway (1967-2006): 544 087 units of mother and childbearing daughter and 399 777 units of mother and child producing son. Main outcome measure Hyperemesis in daughters in mother and childbearing daughter units and hyperemesis in female partners of sons in mother and child producing son units. Results Daughters who were born after a pregnancy complicated by hyperemesis had a 3% risk of having hyperemesis in their own pregnancy, while women who were born after an unaffected pregnancy had a risk of 1.1% (unadjusted odds ratio 2.9, 95% confidence interval 2.4 to 3.6). Female partners of sons who were born after pregnancies complicated by hyperemesis had a risk of 1.2% (1.0, 0.7 to 1.6). Daughters born after a pregnancy not complicated by hyperemesis had an increased risk of the condition if the mother had hyperemesis in a previous or subsequent pregnancy (3.2 (1.6 to 6.4) if hyperemesis had occurred in one of the mother’s previous pregnancies and 3.7 (1.5 to 9.1) if it had occurred in a later pregnancy). Adjustment for maternal age at childbirth, period of birth, and parity did not change the estimates. Restrictions to firstborns did not influence the results. Conclusions Hyperemesis gravidarum is more strongly influenced by the maternal genotype than the fetal genotype, though environmental influences along the maternal line cannot be excluded as contributing factors. PMID:21030362

  11. A non-invasive approach to study lifetime exposure and bioaccumulation of PCBs in protected marine mammals: PBPK modeling in harbor porpoises

    SciTech Connect

    Weijs, Liesbeth; Covaci, Adrian; Yang, Raymond S.H.; Das, Krishna; Blust, Ronny

    2011-10-15

    In the last decade, physiologically based pharmacokinetic (PBPK) models have increasingly been developed to explain the kinetics of environmental pollutants in wildlife. For marine mammals specifically, these models provide a new, non-destructive tool that enables the integration of biomonitoring activities and in vitro studies. The goals of the present study were firstly to develop PBPK models for several environmental relevant PCB congeners in harbor porpoises (Phocoena phocoena), a species that is sensitive to pollution because of its limited metabolic capacity for pollutant transformation. These models were tested using tissue data of porpoises from the Black Sea. Secondly, the predictive power of the models was investigated for time trends in the PCB concentrations in North Sea harbor porpoises between 1990 and 2008. Thirdly, attempts were made to assess metabolic capacities of harbor porpoises for the investigated PCBs. In general, results show that parameter values from other species (rodents, humans) are not always suitable in marine mammal models, most probably due to differences in physiology and exposure. The PCB 149 levels decrease the fastest in male harbor porpoises from the North Sea in a time period of 18 years, whereas the PCB 101 levels decrease the slowest. According to the models, metabolic breakdown of PCB 118 is probably of lesser importance compared to other elimination pathways. For PCB 101 and 149 however, the presence of their metabolites can be attributed to bioaccumulation of metabolites from the prey and to metabolic breakdown of the parent compounds in the harbor porpoises. - Highlights: > PBPK modeling was used to study the kinetics of several PCBs in a marine mammal. > Harbor porpoises are sensitive to pollution and therefore ideal model organisms. > Black Sea data were used for parameterization. > North Sea data for assessing temporal trends (1990-2008). > PBPK modeling is a non-invasive and non-destructive tool.

  12. Using Sport Education to Teach the Lifetime Sport of Golf

    ERIC Educational Resources Information Center

    Scarboro, Shot; Pritchard, Tony

    2015-01-01

    Golf is a lifetime sport activity that can be taught in physical education classes. How one teaches golf in physical education could influence whether students will want to continue to participate outside of physical education. The sport education model (SEM) is an instructional model that promotes student learning in all three domains by ensuring…

  13. Carrier lifetimes in thin-film photovoltaics

    NASA Astrophysics Data System (ADS)

    Baek, Dohyun

    2015-09-01

    The carrier lifetimes in thin-film solar cells are reviewed and discussed. Shockley-Read-Hall recombination is dominant at low carrier density, Auger recombination is dominant under a high injection condition and high carrier density, and surface recombination is dominant under any conditions. Because the surface photovoltage technique is insensitive to the surface condition, it is useful for bulk lifetime measurements. The photoconductance decay technique measures the effective recombination lifetime. The time-resolved photoluminescence technique is very useful for measuring thin-film semiconductor or solar-cell materials lifetime, because the sample is thin, other techniques are not suitable for measuring the lifetime. Many papers have provided time-resolved photoluminescence (TRPL) lifetimes for copper-indium-gallium-selenide (CIGS) and CdTe thin-film solar cell. The TRPL lifetime strongly depends on open-circuit voltage and conversion efficiency; however, the TRPL life time is insensitive to the short-circuit current.

  14. Simulation of GRETINA Lifetime Experiment

    NASA Astrophysics Data System (ADS)

    Littley, Cody; Iwasaki, Hironori; Lemasson, Antoine

    2011-10-01

    In order to understand properties of exotic atomic nuclei, the research group has developed a method to measure the rate of decay of excited states in certain unstable isotopes, for example 66Fe. By measuring the Doppler shift of gamma rays with a so-called plunger device it is possible to deduce with great accuracy the excited-state lifetime. This technique, which is called the Recoil Distance Doppler-shift Method, has precision on the order of one pico second. I will present the development a simulation software package which will help the research team to quantize and to analyze the data from experimental runs. This software is based upon existing software which was used for simulations of the SeGA project. It has been modified to support the GRETINA detector, which is used in the experimental setup for the lifetime measurements. The software makes use GEANT and ROOT toolkits, which are essential for the calculations of the interactions of particles with the detector and the recording of that data.

  15. Electron lifetime in Luttinger liquids

    NASA Astrophysics Data System (ADS)

    Le Hur, Karyn

    2006-10-01

    We investigate the decoherence of the electron wave packet in purely ballistic one-dimensional systems described through the Luttinger liquid (LL). At a finite temperature T and long times t , we show that the electron Green’s function for a fixed wave vector close to one Fermi point decays as exp(-t/τF) —as opposed to the power-law behavior occurring at short times—and the emerging electron lifetime obeys τF-1∝T for spinful as well as spinless electrons. For strong interactions, (TτF)≪1 , reflecting that the electron is not a good Landau quasiparticle in LL’s. We justify that fractionalization is the main source of electron decoherence for spinful as well as spinless electrons clarifying the peculiar electron mass renormalization close to the Fermi points. For spinless electrons and weak interactions, our intuition can be enriched through a diagrammatic approach or Fermi golden rule and through a Johnson-Nyquist noise picture. We stress that the electron lifetime (and the fractional quasiparticles) can be revealed from Aharonov-Bohm experiments or momentum resolved tunneling. We aim to compare the results with those of spin-incoherent and chiral LL’s.

  16. Lifetime Measurement of 26O

    NASA Astrophysics Data System (ADS)

    Redpath, Thomas; MoNA Collaboration

    2017-01-01

    An interesting property of some neutron-unbound systems is true two-neutron emission where the neutrons are emitted simultaneously as opposed to a sequential decay through an intermediate state. Since neutrons are only affected by the angular momentum barrier, the timescale for this process is much shorter than for two proton emission which is dominated by the Coulomb barrier. One such case is 26O where a very low decay energy was measured and the two valence neutrons are expected to occupy d-wave orbitals. Also, the ground state of 25O is located 700 keV higher. In a first experiment, the MoNA collaboration extracted a lifetime of 4 .5-1 . 5 + 1 . 1 (stat) +/- 3(syst) ps with a confidence level of 82%. Recently, an experiment dedicated to measuring the 26O lifetime in order to improve the confidence level of the measurement was performed at NSCL. The experiment utilized a newly developed segmented target which increased the statistics without degrading the resolution. Preliminary results will be presented. NSF PHY-1002511, DOE-NNSA DE-NA0000979.

  17. Corrosion Preventive Compounds Lifetime Testing

    NASA Technical Reports Server (NTRS)

    Hale, Stephanie M.; Kammerer, Catherine C.

    2007-01-01

    Lifetime Testing of Corrosion Preventive Compounds (CPCs) was performed to quantify performance in the various environments to which the Space Shuttle Orbiter is exposed during a flight cycle. Three CPCs are approved for use on the Orbiter: HD Calcium Grease, Dinitrol AV-30, and Braycote 601 EF. These CPCs have been rigorously tested to prove that they mitigate corrosion in typical environments, but little information is available on how they perform in the unique combination of the coastal environment at the launch pad, the vacuum of low-earth orbit, and the extreme heat of reentry. Currently, there is no lifetime or reapplication schedule established for these compounds that is based on this combination of environmental conditions. Aluminum 2024 coupons were coated with the three CPCs and exposed to conditions that simulate the environments to which the Orbiter is exposed. Uncoated Aluminum 2024 coupons were exposed to the environmental conditions as a control. Visual inspection and Electro- Impedance Spectroscopy (EIS) were performed on the samples in order to determine the effectiveness of the CPCs. The samples were processed through five mission life cycles or until the visual inspection revealed the initiation of corrosion and EIS indicated severe degradation of the coating.

  18. Corrosion Preventive Compounds Lifetime Testing

    NASA Technical Reports Server (NTRS)

    Hale, Stephanie M.; Kammerer, Catherine C.; Copp, Tracy L.

    2007-01-01

    Lifetime Testing of Corrosion Preventive Compounds (CPCs) was performed to quantify performance in the various environments to which the Space Shuttle Orbiter is exposed during a flight cycle. Three CPCs are approved for use on the Orbiter: RD Calcium Grease, Dinitrol AV-30, and Braycote 601 EF. These CPCs have been rigorously tested to prove that they mitigate corrosion in typical environments, but little information is available on how they perform in the unique combination of the coastal environment at the launch pad, the vacuum of low-earth orbit, and the extreme heat of reentry. Currently, there is no lifetime or reapplication schedule established for these compounds that is based on this combination of environmental conditions. Aluminum 2024 coupons were coated with the three CPCs and exposed to conditions that simulate the environments to which the Orbiter is exposed. Uncoated Aluminum 2024 coupons were exposed to the environmental conditions as a control. Visual inspection and Electro- Impedance Spectroscopy (EIS) were performed on the samples in order to determine the effectiveness of the CPCs. The samples were processed through five mission life cycles or until the visual inspection revealed the initiation of corrosion and EIS indicated severe degradation of the coating.

  19. Population-Based Incidence and Prevalence of Systemic Lupus Erythematosus

    PubMed Central

    Somers, Emily C.; Marder, Wendy; Cagnoli, Patricia; Lewis, Emily E.; DeGuire, Peter; Gordon, Caroline; Helmick, Charles G.; Wang, Lu; Wing, Jeffrey J.; Dhar, J. Patricia; Leisen, James; Shaltis, Diane; McCune, W. Joseph

    2014-01-01

    Objective To estimate the incidence and prevalence of systemic lupus erythematosus (SLE) in a sociodemographically diverse southeastern Michigan source population of 2.4 million people. Methods SLE cases fulfilling the American College of Rheumatology classification criteria (primary case definition) or meeting rheumatologist-judged SLE criteria (secondary definition) and residing in Wayne or Washtenaw Counties during 2002–2004 were included. Case finding was performed from 6 source types, including hospitals and private specialists. Age-standardized rates were computed, and capture–recapture was performed to estimate underascertainment of cases. Results The overall age-adjusted incidence and prevalence (ACR definition) per 100,000 persons were 5.5 (95% confidence interval [95% CI] 5.0–6.1) and 72.8 (95% CI 70.8–74.8). Among females, the incidence was 9.3 per 100,000 persons and the prevalence was 128.7 per 100,000 persons. Only 7 cases were estimated to have been missed by capture–recapture, adjustment for which did not materially affect the rates. SLE prevalence was 2.3-fold higher in black persons than in white persons, and 10-fold higher in females than in males. Among incident cases, the mean ± SD age at diagnosis was 39.3 ± 16.6 years. Black SLE patients had a higher proportion of renal disease and end-stage renal disease (ESRD) (40.5% and 15.3%, respectively) as compared to white SLE patients (18.8% and 4.5%, respectively). Black patients with renal disease were diagnosed as having SLE at younger age than white patients with renal disease (mean ± SD 34.4 ± 14.9 years versus 41.9 ± 21.3 years; P = 0.05). Conclusion SLE prevalence was higher than has been described in most other population-based studies and reached 1 in 537 among black female persons. There were substantial racial disparities in the burden of SLE, with black patients experiencing earlier age at diagnosis, >2-fold increases in SLE incidence and prevalence, and increased

  20. Cyberbullying among Finnish adolescents – a population-based study

    PubMed Central

    2012-01-01

    Background Cyberbullying, threatening or harassing another via the internet or mobile phones, does not cause physically harm and thus the consequences are less visible. Little research has been performed on the occurrence of cyberbullying among adolescents or the perception of its seriousness. Only a few population-based studies have been published, none of which included research on the witnessing of cyberbullying. Here, we examined exposure to cyberbullying during the last year, and its frequency and perceived seriousness among 12 to 18-year-old adolescents in Finland. We studied four dimensions of cyberbullying: being a victim, bully, or both victim and bully of cyberbullying, and witnessing the cyberbullying of friends. Methods Self-administered questionnaires, including four questions on cyberbullying, were mailed to a representative sample of 12-, 14-, 16-, and 18-year-old Finns in 2009 (the Adolescent Health and Lifestyle Survey). The respondents could answer via the internet or paper questionnaire. Results The number of respondents was 5516 and the response rate was 56%. Girls more often than boys reported experiencing at least one dimension of cyberbullying during the last year. The proportion was highest among 14-year-olds and lowest among 18-year-olds of both sexes. Among girls, the most commonly encountered dimension was witnessing the cyberbullying of friends (16%); and being a victim was slightly more common than being a bully (11% vs. 9%). Among boys, an equal proportion, approximately 10%, had been a victim, a bully, or had witnessed cyberbullying. The proportion of bully-victims was 4%. Serious and disruptive cyberbullying was experienced by 2% of respondents and weekly cyberbullying by 1%; only 0.5% of respondents had been bullied weekly and considered bullying serious and disruptive. Conclusions Adolescents are commonly exposed to cyberbullying, but it is rarely frequent or considered serious or disruptive. Cyberbullying exposure differed between

  1. A systematic review of economic evaluations of population-based sodium reduction interventions

    PubMed Central

    Hope, Silvia F.; Webster, Jacqui; Trieu, Kathy; Pillay, Arti; Ieremia, Merina; Bell, Colin; Snowdon, Wendy; Neal, Bruce; Moodie, Marj

    2017-01-01

    Objective To summarise evidence describing the cost-effectiveness of population-based interventions targeting sodium reduction. Methods A systematic search of published and grey literature databases and websites was conducted using specified key words. Characteristics of identified economic evaluations were recorded, and included studies were appraised for reporting quality using the Consolidated Health Economic Evaluation Reporting Standards (CHEERS) checklist. Results Twenty studies met the study inclusion criteria and received a full paper review. Fourteen studies were identified as full economic evaluations in that they included both costs and benefits associated with an intervention measured against a comparator. Most studies were modelling exercises based on scenarios for achieving salt reduction and assumed effects on health outcomes. All 14 studies concluded that their specified intervention(s) targeting reductions in population sodium consumption were cost-effective, and in the majority of cases, were cost saving. Just over half the studies (8/14) were assessed as being of ‘excellent’ reporting quality, five studies fell into the ‘very good’ quality category and one into the ‘good’ category. All of the identified evaluations were based on modelling, whereby inputs for all the key parameters including the effect size were either drawn from published datasets, existing literature or based on expert advice. Conclusion Despite a clear increase in evaluations of salt reduction programs in recent years, this review identified relatively few economic evaluations of population salt reduction interventions. None of the studies were based on actual implementation of intervention(s) and the associated collection of new empirical data. The studies universally showed that population-based salt reduction strategies are likely to be cost effective or cost saving. However, given the reliance on modelling, there is a need for the effectiveness of new

  2. New detectors to explore the lifetime frontier

    NASA Astrophysics Data System (ADS)

    Chou, John Paul; Curtin, David; Lubatti, H. J.

    2017-04-01

    Long-lived particles (LLPs) are a common feature in many beyond the Standard Model theories, including supersymmetry, and are generically produced in exotic Higgs decays. Unfortunately, no existing or proposed search strategy will be able to observe the decay of non-hadronic electrically neutral LLPs with masses above ∼ GeV and lifetimes near the limit set by Big Bang Nucleosynthesis (BBN), cτ ≲107-108 m. We propose the MATHUSLA surface detector concept (MAssive Timing Hodoscope for Ultra Stable neutraL pArticles), which can be implemented with existing technology and in time for the high luminosity LHC upgrade to find such ultra-long-lived particles (ULLPs), whether produced in exotic Higgs decays or more general production modes. We also advocate a dedicated LLP detector at a future 100 TeV collider, where a modestly sized underground design can discover ULLPs with lifetimes at the BBN limit produced in sub-percent level exotic Higgs decays.

  3. Discriminating Famous from Fictional Names Based on Lifetime Experience: Evidence in Support of a Signal-Detection Model Based on Finite Mixture Distributions

    ERIC Educational Resources Information Center

    Bowles, Ben; Harlow, Iain M.; Meeking, Melissa M.; Kohler, Stefan

    2012-01-01

    It is widely accepted that signal-detection mechanisms contribute to item-recognition memory decisions that involve discriminations between targets and lures based on a controlled laboratory study episode. Here, the authors employed mathematical modeling of receiver operating characteristics (ROC) to determine whether and how a signal-detection…

  4. Progress toward a new beam measurement of the neutron lifetime

    NASA Astrophysics Data System (ADS)

    Hoogerheide, Shannon Fogwell; BL2 Collaboration

    2017-01-01

    Neutron beta decay is the simplest example of nuclear beta decay. A precise value of the neutron lifetime is important for consistency tests of the Standard Model and Big Bang Nucleosynthesis models. The beam neutron lifetime method requires the absolute counting of the decay protons in a neutron beam of precisely known flux. Recent work has resulted in improvements in both the neutron and proton detection systems that should permit a significant reduction in systematic uncertainties. A new measurement of the neutron lifetime using the beam method is underway at the National Institute of Standards and Technology Center for Neutron Research. The projected uncertainty of this new measurement is 1 s. An overview of the measurement, its current status, and the technical improvements will be discussed.

  5. Progress toward a new beam measurement of the neutron lifetime

    NASA Astrophysics Data System (ADS)

    Hoogerheide, Shannon Fogwell

    2016-09-01

    Neutron beta decay is the simplest example of nuclear beta decay. A precise value of the neutron lifetime is important for consistency tests of the Standard Model and Big Bang Nucleosysnthesis models. The beam neutron lifetime method requires the absolute counting of the decay protons in a neutron beam of precisely known flux. Recent work has resulted in improvements in both the neutron and proton detection systems that should permit a significant reduction in systematic uncertainties. A new measurement of the neutron lifetime using the beam method will be performed at the National Institute of Standards and Technology Center for Neutron Research. The projected uncertainty of this new measurement is 1 s. An overview of the measurement and the technical improvements will be discussed.

  6. Photobleaching effects on in vivo skin autofluorescence lifetime

    NASA Astrophysics Data System (ADS)

    Ferulova, Inesa; Lihachev, Alexey; Spigulis, Janis

    2015-05-01

    The autofluorescence lifetime of healthy human skin was measured using excitation provided by a picosecond diode laser operating at a wavelength of 405 nm and with fluorescence emission collected at 475 and 560 nm. In addition, spectral and temporal responses of healthy human skin and intradermal nevus in the spectral range 460 to 610 nm were studied before and after photobleaching. A decrease in the autofluorescences lifetimes changes was observed after photobleaching of human skin. A three-exponential model was used to fit the signals, and under this model, the most significant photoinduced changes were observed for the slowest lifetime component in healthy skin at the spectral range 520 to 610 nm and intradermal nevus at the spectral range 460 to 610 nm.

  7. Accelerated lifetime test of vibration isolator made of Metal Rubber material

    NASA Astrophysics Data System (ADS)

    Ao, Hongrui; Ma, Yong; Wang, Xianbiao; Chen, Jianye; Jiang, Hongyuan

    2017-01-01

    The Metal Rubber material (MR) is a kind of material with nonlinear damping characteristics for its application in the field of aerospace, petrochemical industry and so on. The study on the lifetime of MR material is impendent to its application in engineering. Based on the dynamic characteristic of MR, the accelerated lifetime experiments of vibration isolators made of MR working under random vibration load were conducted. The effects of structural parameters of MR components on the lifetime of isolators were studied and modelled with the fitting curves of degradation data. The lifetime prediction methods were proposed based on the models.

  8. Waiting time disparities in breast cancer diagnosis and treatment: a population-based study in France.

    PubMed

    Molinié, F; Leux, C; Delafosse, P; Ayrault-Piault, S; Arveux, P; Woronoff, A S; Guizard, A V; Velten, M; Ganry, O; Bara, S; Daubisse-Marliac, L; Tretarre, B

    2013-10-01

    Waiting times are key indicators of a health's system performance, but are not routinely available in France. We studied waiting times for diagnosis and treatment according to patients' characteristics, tumours' characteristics and medical management options in a sample of 1494 breast cancers recorded in population-based registries. The median waiting time from the first imaging detection to the treatment initiation was 34 days. Older age, co-morbidity, smaller size of tumour, detection by organised screening, biopsy, increasing number of specimens removed, multidisciplinary consulting meetings and surgery as initial treatment were related to increased waiting times in multivariate models. Many of these factors were related to good practices guidelines. However, the strong influence of organised screening programme and the disparity of waiting times according to geographical areas were of concern. Better scheduling of diagnostic tests and treatment propositions should improve waiting times in the management of breast cancer in France.

  9. Influences on lifetime of wire ropes in traction lifts

    NASA Astrophysics Data System (ADS)

    Vogel, W.

    2016-05-01

    Traction lifts are complex systems with rotating and translating moving masses, springs and dampers and several system inputs from the lifts and the users. The wire ropes are essential mechanical elements. The mechanical properties of the ropes in use depend on the rope construction, the load situation, nonlinearities and the lift dimensions. The mechanical properties are important for the proper use in lifts and the ride quality. But first of all the wire ropes (for all other suspension means as well) have to satisfy the safety relevant requirements sufficient lifetime, reliable determination of discard and sufficient and limited traction capacity. The lifetime of the wire ropes better the number of trips until rope discard depends on a lot of parameters of the rope and the rope application eg use of plastic deflection sheaves and reverse bending layouts. New challenges for rope lifetime are resulting from the more or less open D/d-ratio limits possible by certificates concerning the examination of conformity by notified bodies. This paper will highlight the basics of wire rope technology, the endurance and lifetime of wire ropes running over sheaves, and the different influences from the ropes and more and more important from the lift application parameters. Very often underestimated are the influences of transport, storage, installation and maintenance. With this background we will lead over to the calculation methods of wire rope lifetime considering the actual findings of wire rope endurance research. We'll show in this paper new and innovative facts as the influence of rope length and size factor in the lifetime formular, the reduction of lifetime caused by traction grooves, the new model for the calculation in reverse bending operations and the statistically firmed possibilities for machine roomless lifts (MRL) under very small bending conditions.

  10. Scaling Laws for the Lifetimes of Governments in the Sznajd Democracy

    NASA Astrophysics Data System (ADS)

    Schneider, Johannes J.; Hirtreiter, Christian

    We investigate the lifetimes of governments in the original and a randomized one-dimensional Sznajd model. We find various scaling laws for the lifetime of the democracy and for the reigning time of governments in this model, depending on the system size N.

  11. Inhomogeneous dephasing masks coherence lifetimes in ensemble measurements

    SciTech Connect

    Pelzer, Kenley M.; Griffin, Graham B.; Engel, Gregory S.; Gray, Stephen K.

    2012-04-28

    An open question at the forefront of modern physical sciences is what role, if any, quantum effects may play in biological sensing and energy transport mechanisms. One area of such research concerns the possibility of coherent energy transport in photosynthetic systems. Spectroscopic evidence of long-lived quantum coherence in photosynthetic light-harvesting pigment protein complexes (PPCs), along with theoretical modeling of PPCs, has indicated that coherent energy transport might boost efficiency of energy transport in photosynthesis. Accurate assessment of coherence lifetimes is crucial for modeling the extent to which quantum effects participate in this energy transfer, because such quantum effects can only contribute to mechanisms proceeding on timescales over which the coherences persist. While spectroscopy is a useful way to measure coherence lifetimes, inhomogeneity in the transition energies across the measured ensemble may lead to underestimation of coherence lifetimes from spectroscopic experiments. Theoretical models of antenna complexes generally model a single system, and direct comparison of single system models to ensemble averaged experimental data may lead to systematic underestimation of coherence lifetimes, distorting much of the current discussion. In this study, we use simulations of the Fenna-Matthews-Olson complex to model single complexes as well as averaged ensembles to demonstrate and roughly quantify the effect of averaging over an inhomogeneous ensemble on measured coherence lifetimes. We choose to model the Fenna-Matthews-Olson complex because that system has been a focus for much of the recent discussion of quantum effects in biology, and use an early version of the well known environment-assisted quantum transport model to facilitate straightforward comparison between the current model and past work. Although ensemble inhomogeneity is known to lead to shorter lifetimes of observed oscillations (simply inhomogeneous spectral

  12. Lifetime measurements for bottom hadrons

    SciTech Connect

    Wolf, G.

    1984-09-01

    The review of lifetime measurements of bottom hadrons begins with a first measurement by JADE, followed by similar measurements by MAC and MKII groups. New MAC data are reviewed based on a total of 75,000 multihadron events taken at a c.m. energy of 29 GeV. According to Monte Carlo calculations, 18% of the lepton candidates stem from charm decay and roughly 30% were misidentified hadrons. DELCO studied electrons obtained from 42,000 multihadron events at 29 GeV. The electrons were identified by means of Cerenkov counters. JADE analayzed 22,000 multihadron events at 35 GeV. Data were analyzed using two methods - one using a sample of b-enriched events, and the other using weighted distributions. The TASSO results were obtained with two different configurations of the detector - one of which used a drift chamber and the other a vertex detector. (LEW)

  13. The He II Proximity Effect and The Lifetime of Quasars

    NASA Astrophysics Data System (ADS)

    Khrykin, I. S.; Hennawi, J. F.; McQuinn, M.; Worseck, G.

    2016-06-01

    The lifetime of quasars is fundamental for understanding the growth of supermassive black holes, and is an important ingredient in models of the reionization of the intergalactic medium (IGM). However, despite various attempts to determine quasar lifetimes, current estimates from a variety of methods are uncertain by orders of magnitude. This work combines cosmological hydrodynamical simulations and 1D radiative transfer to investigate the structure and evolution of the He ii Lyα proximity zones around quasars at z ≃ 3-4. We show that the time evolution in the proximity zone can be described by a simple analytical model for the approach of the He ii fraction {x}{He{{II}}}(t) to ionization equilibrium, and use this picture to illustrate how the transmission profile depends on the quasar lifetime, quasar UV luminosity, and the ionization state of Helium in the ambient IGM (i.e., the average He ii fraction, or equivalently the metagalactic He ii ionizing background). A significant degeneracy exists between the lifetime and the average He ii fraction, however the latter can be determined from measurements of the He ii Lyα optical depth far from quasars, allowing the lifetime to be measured. We advocate stacking existing He ii quasar spectra at z ˜ 3, and show that the shape of this average proximity zone profile is sensitive to lifetimes as long as ˜30 Myr. At higher redshift z ˜ 4 where the He ii fraction is poorly constrained, degeneracies will make it challenging to determine these parameters independently. Our analytical model for He ii proximity zones should also provide a useful description of the properties of H i proximity zones around quasars at z ≃ 6-7.

  14. High-Resolution Association Mapping of Quantitative Trait Loci: A Population-Based Approach

    PubMed Central

    Fan, Ruzong; Jung, Jeesun; Jin, Lei

    2006-01-01

    In this article, population-based regression models are proposed for high-resolution linkage disequilibrium mapping of quantitative trait loci (QTL). Two regression models, the “genotype effect model” and the “additive effect model,” are proposed to model the association between the markers and the trait locus. The marker can be either diallelic or multiallelic. If only one marker is used, the method is similar to a classical setting by Nielsen and Weir, and the additive effect model is equivalent to the haplotype trend regression (HTR) method by Zaykin et al. If two/multiple marker data with phase ambiguity are used in the analysis, the proposed models can be used to analyze the data directly. By analytical formulas, we show that the genotype effect model can be used to model the additive and dominance effects simultaneously; the additive effect model takes care of the additive effect only. On the basis of the two models, F-test statistics are proposed to test association between the QTL and markers. By a simulation study, we show that the two models have reasonable type I error rates for a data set of moderate sample size. The noncentrality parameter approximations of F-test statistics are derived to make power calculation and comparison. By a simulation study, it is found that the noncentrality parameter approximations of F-test statistics work very well. Using the noncentrality parameter approximations, we compare the power of the two models with that of the HTR. In addition, a simulation study is performed to make a comparison on the basis of the haplotype frequencies of 10 SNPs of angiotensin-1 converting enzyme (ACE) genes. PMID:16172503

  15. Lifetime risk of diabetes among First Nations and non–First Nations people

    PubMed Central

    Turin, Tanvir Chowdhury; Saad, Nathalie; Jun, Min; Tonelli, Marcello; Ma, Zhihai; Barnabe, Cheryl Carmelle Marie; Manns, Braden; Hemmelgarn, Brenda

    2016-01-01

    Background: Lifetime risk is a relatively straightforward measure used to communicate disease burden, representing the cumulative risk of an outcome during the remainder of an individual’s life starting from a disease-free index age. We estimated the lifetime risk of diabetes among men and women in both First Nations and non–First Nations populations using a cohort of adults in a single Canadian province. Methods: We used a population-based cohort consisting of Alberta residents from 1997 to 2008 who were free of diabetes at cohort entry to estimate the lifetime risk of diabetes among First Nations and non–First Nations people. We calculated age-specific incidence rates with the person-year method in 5-year bands. We estimated the sex- and index-age–specific lifetime risk of incident diabetes, after adjusting for the competing risk of death. Results: The cohort included 70 631 First Nations and 2 732 214 non–First Nations people aged 18 years or older. The lifetime risk of diabetes at 20 years of age was 75.6% among men and 87.3% among women in the First Nations group, as compared with 55.6% among men and 46.5% among women in the non–First Nations group. The risk was higher among First Nations people than among non–First Nations people for all index ages and for both sexes. Among non–First Nations people, men had a higher lifetime risk of diabetes than women across all index ages. In contrast, among First Nations people, women had a higher lifetime risk than men across all index ages. Interpretation: About 8 in 10 First Nations people and about 5 in 10 non–First Nations people of young age will develop diabetes in their remaining lifetime. These population-based estimates may help health care planners and decision-makers set priorities and increase public awareness and interest in the prevention of diabetes. PMID:27647609

  16. Single photon counting fluorescence lifetime detection of pericellular oxygen concentrations

    NASA Astrophysics Data System (ADS)

    Hosny, Neveen A.; Lee, David A.; Knight, Martin M.

    2012-01-01

    Fluorescence lifetime imaging microscopy offers a non-invasive method for quantifying local oxygen concentrations. However, existing methods are either invasive, require custom-made systems, or show limited spatial resolution. Therefore, these methods are unsuitable for investigation of pericellular oxygen concentrations. This study describes an adaptation of commercially available equipment which has been optimized for quantitative extracellular oxygen detection with high lifetime accuracy and spatial resolution while avoiding systematic photon pile-up. The oxygen sensitive fluorescent dye, tris(2,2'-bipyridyl)ruthenium(II) chloride hexahydrate [Ru(bipy)3]2+, was excited using a two-photon excitation laser. Lifetime was measured using a Becker & Hickl time-correlated single photon counting, which will be referred to as a TCSPC card. [Ru(bipy)3]2+ characterization studies quantified the influences of temperature, pH, cellular culture media and oxygen on the fluorescence lifetime measurements. This provided a precisely calibrated and accurate system for quantification of pericellular oxygen concentration based on measured lifetimes. Using this technique, quantification of oxygen concentrations around isolated viable chondrocytes, seeded in three-dimensional agarose gel, revealed a subpopulation of cells that exhibited significant spatial oxygen gradients such that oxygen concentration reduced with increasing proximity to the cell. This technique provides a powerful tool for quantifying spatial oxygen gradients within three-dimensional cellular models.

  17. Photoacoustic imaging of the excited state lifetime of fluorophores

    NASA Astrophysics Data System (ADS)

    Märk, Julia; Schmitt, Franz-Josef; Laufer, Jan

    2016-05-01

    Photoacoustic (PA) imaging using pump-probe excitation has been shown to allow the detection and visualization of fluorescent contrast agents. The technique relies upon inducing stimulated emission using pump and probe pulses at excitation wavelengths that correspond to the absorption and fluorescence spectra. By changing the time delay between the pulses, the excited state lifetime of the fluorophore is modulated to vary the amount of thermalized energy, and hence PA signal amplitude, to provide fluorophore-specific PA contrast. In this study, this approach was extended to the detection of differences in the excited state lifetime of fluorophores. PA waveforms were measured in solutions of a near-infrared fluorophore using simultaneous and time-delayed pump-probe excitation. The lifetime of the fluorophore solutions was varied by using different solvents and quencher concentrations. By calculating difference signals and by plotting their amplitude as a function of pump-probe time delay, a correlation with the excited state lifetime of the fluorophore was observed. The results agreed with the output of a forward model of the PA signal generation in fluorophores. The application of this method to tomographic PA imaging of differences in the excited state lifetime was demonstrated in tissue phantom experiments.

  18. Predictors of Cerebral Palsy in Very Preterm Infants: The EPIPAGE Prospective Population-Based Cohort Study

    ERIC Educational Resources Information Center

    Beaino, Ghada; Khoshnood, Babak; Kaminski, Monique; Pierrat, Veronique; Marret, Stephane; Matis, Jacqueline; Ledesert, Bernard; Thiriez, Gerard; Fresson, Jeanne; Roze, Jean-Christophe; Zupan-Simunek, Veronique; Arnaud, Catherine; Burguet, Antoine; Larroque, Beatrice; Breart, Gerard; Ancel, Pierre-Yves

    2010-01-01

    Aim: The aim of this study was to assess the independent role of cerebral lesions on ultrasound scan, and several other neonatal and obstetric factors, as potential predictors of cerebral palsy (CP) in a large population-based cohort of very preterm infants. Method: As part of EPIPAGE, a population-based prospective cohort study, perinatal data…

  19. Optimal estimator for tomographic fluorescence lifetime multiplexing

    PubMed Central

    Hou, Steven S.; Bacskai, Brian J.; Kumar, Anand T. N.

    2016-01-01

    We use the model resolution matrix to analytically derive an optimal Bayesian estimator for multiparameter inverse problems that simultaneously minimizes inter-parameter cross talk and the total reconstruction error. Application of this estimator to time-domain diffuse fluorescence imaging shows that the optimal estimator for lifetime multiplexing is identical to a previously developed asymptotic time-domain (ATD) approach, except for the inclusion of a diagonal regularization term containing decay amplitude uncertainties. We show that, while the optimal estimator and ATD provide zero cross talk, the optimal estimator provides lower reconstruction error, while ATD results in superior relative quantitation. The framework presented here is generally applicable to other multiplexing problems where the simultaneous and accurate relative quantitation of multiple parameters is of interest. PMID:27192234

  20. Lifetime measurements in {sup 133}Ce

    SciTech Connect

    Emediato, L.G.; Rao, M.N.; Medina, N.H.; Seale, W.A.; Botelho, S.; Ribas, R.V.; Oliveira, J.R.; Cybulska, E.W.; Espinoza-Quinones, F.R.; Guimaraes, V.; Rizzutto, M.A.; Acquadro, J.C.

    1997-04-01

    Lifetimes of low-lying levels in the one- and three-quasiparticle bands in {sup 133}Ce have been measured using the recoil-distance Doppler-shift technique. The E2 transition strengths extracted for the negative parity yrast states are well described by the triaxial-rotor-plus-quasiparticle and the geometrical models, but the interacting-boson-plus-fermion predictions are too small by about a factor of 3. The B(M1) values extracted for the levels in the positive parity three-quasiparticle band are consistent with the previous {nu}h{sub 11/2}{circle_times}{pi}h{sub 11/2}{circle_times}{pi}g{sub 7/2} configuration assignment to this band. {copyright} {ital 1997} {ital The American Physical Society}

  1. Surface plasmon lifetime in metal nanoshells

    NASA Astrophysics Data System (ADS)

    Kirakosyan, Arman S.; Stockman, Mark I.; Shahbazyan, Tigran V.

    2016-10-01

    The lifetime of localized surface plasmon plays an important role in many aspects of plasmonics and its applications. In small metal nanostructures, the dominant mechanism of plasmon decay is size-dependent Landau damping. We performed quantum-mechanical calculations of Landau damping for the bright surface plasmon mode in a metal nanoshell with dielectric core. In contrast to the conventional model based on the electron surface scattering, we found that the damping rate decreases as the nanoshell thickness is reduced. The origin of this behavior is traced to the spatial distribution of plasmon local field in the metal shell. We also found that, due to the interference of electron scattering amplitudes from the two nanoshell metal surfaces, the damping rate exhibits pronounced quantum beats with changing shell thickness.

  2. Finite quasiparticle lifetime in disordered superconductors.

    SciTech Connect

    Zemlicka, M.; Neilinger, P.; Trgala, M; Rehak, M; Manca, D.; Grajcar, M.; Szabo, P.; Samuely, P.; Gazi, S.; Hubner, U.; Vinokur, V. M.; Il'ichev, E.

    2015-12-08

    We investigate the complex conductivity of a highly disordered MoC superconducting film with k(F)l approximate to 1, where k(F) is the Fermi wave number and l is the mean free path, derived from experimental transmission characteristics of coplanar waveguide resonators in a wide temperature range below the superconducting transition temperature T-c. We find that the original Mattis-Bardeen model with a finite quasiparticle lifetime, tau, offers a perfect description of the experimentally observed complex conductivity. We show that iota is appreciably reduced by scattering effects. Characteristics of the scattering centers are independently found by scanning tunneling spectroscopy and agree with those determined from the complex conductivity.

  3. Position sensitive detector for fluorescence lifetime imaging

    NASA Astrophysics Data System (ADS)

    Prokazov, Y.; Turbin, E.; Weber, A.; Hartig, R.; Zuschratter, W.

    2014-12-01

    We present a detector system with a microchannel plate based photomultiplier tube (MCP-PMT) and its application for fluorescence lifetime imaging (FLIM) in visible light. A capacity coupled imaging technique (charge image) combined with a charge division anode is employed for the positional readout. Using an artificial neural network's (ANN) computation model we are able to reconstruct the position of the incident photon as precise as 20 microns over the detector active area of 25 mm diameter. Thus, the resulting image quality corresponds roughly to a megapixel conventional CCD camera. Importantly, it is feasible to reach such resolution using only 9 charge acquisition channels supporting the anode structure of 14 interconnected readout electrodes. Additionally, the system features better than 50 ps temporal resolution allowing single photon counting FLIM acquisition with a regular fluorescence wide-field microscope.

  4. Neutron lifetime measurement with pulsed beam at JPARC: Overview

    NASA Astrophysics Data System (ADS)

    Mishima, Kenji; Ino, Takashi; Taketani, Kaoru; Yamada, Takahito; Katayama, Ryo; Higashi, Nao; Yokoyama, Harumichi; Sumino, Hirochika; Yamashita, Satoru; Sakakibara, Risa; Sugino, Tomoaki; Kitaguchi, Masaaki; Hirota, Katsuya; Shimizu, Hirohiko M.; Tanaka, Genki; Sumi, Naoyuki; Otono, Hidetoshi; Yoshioka, Tamaki; Kitahara, Ryunosuke; Iwashita, Yoshihisa; Oide, Hideyuki; Shima, Tatsushi; Seki, Yoshichika; NOP Collaboration

    2014-09-01

    The neutron lifetime is an important parameter for a test of the Standard Model of elementary particles, as well for the production of light mass nuclei in big bang nucleosynthesis. There are two principally different approaches to measure the neutron lifetime: In-beam methods and storage of ultracold neutron. At present, there is a discrepancy of 8.4 sec (3.8 sigma) between the two methods. We are performing a new In-beam experiment with an intense pulsed neutron source at J-PARC, which has different systematic uncertainties from the previous experiments. We introduce the overview of the experiment and report present status.

  5. Photovoltaic lifetime and degradation science statistical pathway development: acrylic degradation

    NASA Astrophysics Data System (ADS)

    Bruckman, Laura S.; Wheeler, Nicholas R.; Kidd, Ian V.; Sun, Jiayang; French, Roger H.

    2013-09-01

    In order to optimize and extend the life of photovoltaics (PV) modules, scienti c and mechanistic statistical analytics must be performed on a large sample of materials, components and systems. Statistically signi - cant relationships were investigated between di erent mechanistically based variables to develop a statistical pathway diagram for the degradation of acrylic that is important in concentrating photovoltaics. The statisti- cally signi cant relationships were investigated using lifetime and degradation science using a domain knowledge semi-supervised generalized structural equation modeling (semi-gSEM. Predictive analytics and prognostics are informed from the statistical pathway diagram in order to predictively understand the lifetime of PV modules in di erent stress conditions and help with these critical lifetime technologies.

  6. Developing and Testing a Bayesian Analysis of Fluorescence Lifetime Measurements

    PubMed Central

    Needleman, Daniel J.

    2017-01-01

    FRET measurements can provide dynamic spatial information on length scales smaller than the diffraction limit of light. Several methods exist to measure FRET between fluorophores, including Fluorescence Lifetime Imaging Microscopy (FLIM), which relies on the reduction of fluorescence lifetime when a fluorophore is undergoing FRET. FLIM measurements take the form of histograms of photon arrival times, containing contributions from a mixed population of fluorophores both undergoing and not undergoing FRET, with the measured distribution being a mixture of exponentials of different lifetimes. Here, we present an analysis method based on Bayesian inference that rigorously takes into account several experimental complications. We test the precision and accuracy of our analysis on controlled experimental data and verify that we can faithfully extract model parameters, both in the low-photon and low-fraction regimes. PMID:28060890

  7. Radiative lifetimes and cooling functions for astrophysically important molecules

    NASA Astrophysics Data System (ADS)

    Tennyson, Jonathan; Hulme, Kelsey; Naim, Omree K.; Yurchenko, Sergei N.

    2016-02-01

    Extensive line lists generated as part of the ExoMol project are used to compute lifetimes for individual rotational, rovibrational and rovibronic excited states, and temperature-dependent cooling functions by summing over all dipole-allowed transitions for the states concerned. Results are presented for SiO, CaH, AlO, ScH, H2O and methane. The results for CH4 are particularly unusual with four excited states with no dipole-allowed decay route and several others, where these decays lead to exceptionally long lifetimes. These lifetime data should be useful in models of masers and estimates of critical densities, and can provide a link with laboratory measurements. Cooling functions are important in stellar and planet formation.

  8. Systems and methods for circuit lifetime evaluation

    NASA Technical Reports Server (NTRS)

    Heaps, Timothy L. (Inventor); Sheldon, Douglas J. (Inventor); Bowerman, Paul N. (Inventor); Everline, Chester J. (Inventor); Shalom, Eddy (Inventor); Rasmussen, Robert D. (Inventor)

    2013-01-01

    Systems and methods for estimating the lifetime of an electrical system in accordance with embodiments of the invention are disclosed. One embodiment of the invention includes iteratively performing Worst Case Analysis (WCA) on a system design with respect to different system lifetimes using a computer to determine the lifetime at which the worst case performance of the system indicates the system will pass with zero margin or fail within a predetermined margin for error given the environment experienced by the system during its lifetime. In addition, performing WCA on a system with respect to a specific system lifetime includes identifying subcircuits within the system, performing Extreme Value Analysis (EVA) with respect to each subcircuit to determine whether the subcircuit fails EVA for the specific system lifetime, when the subcircuit passes EVA, determining that the subcircuit does not fail WCA for the specified system lifetime, when a subcircuit fails EVA performing at least one additional WCA process that provides a tighter bound on the WCA than EVA to determine whether the subcircuit fails WCA for the specified system lifetime, determining that the system passes WCA with respect to the specific system lifetime when all subcircuits pass WCA, and determining that the system fails WCA when at least one subcircuit fails WCA.

  9. Measurement of masses and lifetimes of B hadrons

    SciTech Connect

    Filthaut, F.; /Nijmegen U.

    2007-05-01

    We present recent measurements by the CDF and D{O} Collaborations at the Tevatron Collider on the masses and lifetimes of B hadrons. The results are compared to predictions based on Heavy Quark Effective Theory, lattice gauge theory, and quark models.

  10. Bowel Obstruction in Elderly Ovarian Cancer Patients: A Population-Based Study

    PubMed Central

    Mooney, Stephen J.; Winner, Megan; Hershman, Dawn L.; Wright, Jason D.; Feingold, Daniel L.; Allendorf, John D.; Neugut, Alfred I.

    2013-01-01

    PURPOSE Bowel obstruction is a common pre-terminal event in abdominal/pelvic cancer that has mainly been described in small single-institution studies. We used a large, population-based database to investigate the incidence, management, and outcomes of obstruction in ovarian cancer patients. PATIENTS AND METHODS We identified patients with stages IC-IV ovarian cancer, aged 65 years or older, in the Surveillance, Epidemiology and End Results (SEER)-Medicare database diagnosed between January 1, 1991 and December 31, 2005. We modeled predictors of inpatient hospitalization for bowel obstruction after cancer diagnosis, categorized management of obstruction, and analyzed the associations between treatment for obstruction and outcomes. RESULTS Of 8607 women with ovarian cancer, 1518 (17.6%) were hospitalized for obstruction subsequent to cancer diagnosis. Obstruction at cancer diagnosis (HR=2.17, 95% CI: 1.86–2.52) and mucinous tumor histology (HR=1.45, 95% CI: 1.15–1.83) were associated with increased risk of subsequent obstruction. Surgical management of obstruction was associated with lower 30-day mortality (13.4% in women managed surgically vs. 20.2% in women managed non-surgically), but equivalent survival after 30 days and equivalent rates of post-obstruction chemotherapy. Median post-obstruction survival was 382 days in women with obstructions of adhesive origin and 93 days in others. CONCLUSION In this large-scale, population-based assessment of patients with advanced ovarian cancer, nearly 20% of women developed bowel obstruction after cancer diagnosis. While obstruction due to adhesions did not signal the end of life, all other obstructions were pre-terminal events for the majority of patients regardless of treatment. PMID:23274561

  11. Hip Fracture in People with Erectile Dysfunction: A Nationwide Population-Based Cohort Study

    PubMed Central

    Wu, Chieh-Hsin; Tung, Yi-Ching; Lin, Tzu-Kang; Chai, Chee-Yin; Su, Yu-Feng; Tsai, Tai-Hsin; Tsai, Cheng-Yu; Lu, Ying-Yi; Lin, Chih-Lung

    2016-01-01

    The aims of this study were to investigate the risk of hip fracture and contributing factors in patients with erectile dysfunction(ED). This population-based study was performed using the Taiwan National Health Insurance Research Database. The analysis included4636 patients aged ≥ 40 years who had been diagnosed with ED (International Classification of Diseases, Ninth Revision, Clinical Modification codes 302.72, 607.84) during 1996–2010. The control group included 18,544 randomly selected age-matched patients without ED (1:4 ratio). The association between ED and hip fracture risk was estimated using a Cox proportional hazard regression model. During the follow-up period, 59 (1.27%) patients in the ED group and 140 (0.75%) patients in the non-ED group developed hip fracture. After adjusting for covariates, the overall incidence of hip fracture was 3.74-times higher in the ED group than in the non-ED group (2.03 vs. 0.50 per 1000 person-years, respectively). The difference in the overall incidence of hip fracture was largest during the 3-year follow-up period (hazard ratio = 7.85; 95% confidence interval = 2.94–20.96; P <0.0001). To the best of our knowledge, this nationwide population-based study is the first to investigate the relationship between ED and subsequent hip fracture in an Asian population. The results showed that ED patients had a higher risk of developing hip fracture. Patients with ED, particularly those aged 40–59 years, should undergo bone mineral density examinations as early as possible and should take measures to reduce the risk of falls. PMID:27078254

  12. Organization of population-based cancer control programs: Europe and the world.

    PubMed

    Otter, Renée; Qiao, You-Lin; Burton, Robert; Samiei, Massoud; Parkin, Max; Trapido, Edward; Weller, David; Magrath, Ian; Sutcliffe, Simon

    2009-01-01

    As cancer is to a large extent avoidable and treatable, a cancer control program should be able to reduce mortality and morbidity and improve the quality of life of cancer patients and their families. However, the extent to which the goals of a cancer control program can be achieved will depend on the resource constraints a country faces. Such population-based cancer control plans should prioritize effective interventions and programs that are beneficial to the largest part of the population, and should include activities devoted to prevention, screening and early detection, treatment, palliation and end-of-life care, and rehabilitation. In order to develop a successful cancer control program, leadership and the relevant stakeholders, including patient organizations, need to be identified early on in the process so that all partners can take ownership and responsibility for the program. Various tools have been developed to aid them in the planning and implementation process. However, countries developing a national cancer control program would benefit from a discussion of different models for planning and delivery of population-based cancer control in settings with differing levels of resource commitment, in order to determine how best to proceed given their current level of commitment, political engagement and resources. As the priority assigned to different components of cancer control will differ depending on available resources and the burden and pattern of cancer, it is important to consider the relative roles of prevention, early detection, diagnosis, treatment, rehabilitation and palliative care in a cancer control program, as well as how to align available resources to meet prioritized needs. Experiences from countries with differing levels of resources are presented and serve to illustrate the difficulties in developing and implementing cancer control programs, as well as the innovative strategies that are being used to maximize available resources and

  13. Preoperative risk score predicting 90-day mortality after liver resection in a population-based study.

    PubMed

    Chang, Chun-Ming; Yin, Wen-Yao; Su, Yu-Chieh; Wei, Chang-Kao; Lee, Cheng-Hung; Juang, Shiun-Yang; Chen, Yi-Ting; Chen, Jin-Cherng; Lee, Ching-Chih

    2014-09-01

    The impact of important preexisting comorbidities, such as liver and renal disease, on the outcome of liver resection remains unclear. Identification of patients at risk of mortality will aid in improving preoperative preparations. The purpose of this study is to develop and validate a population-based score based on available preoperative and predictable parameters predicting 90-day mortality after liver resection using data from a hepatitis endemic country.We identified 13,159 patients who underwent liver resection between 2002 and 2006 in the Taiwan National Health Insurance Research Database. In a randomly selected half of the total patients, multivariate logistic regression analysis was used to develop a prediction score for estimating the risk of 90-day mortality by patient demographics, preoperative liver disease and comorbidities, indication for surgery, and procedure type. The score was validated with the remaining half of the patients.Overall 90-day mortality was 3.9%. Predictive characteristics included in the model were age, preexisting cirrhosis-related complications, ischemic heart disease, heart failure, cerebrovascular disease, renal disease, malignancy, and procedure type. Four risk groups were stratified by mortality scores of 1.1%, 2.2%, 7.7%, and 15%. Preexisting renal disease and cirrhosis-related complications were the strongest predictors. The score discriminated well in both the derivation and validation sets with c-statistics of 0.75 and 0.75, respectively.This population-based score could identify patients at risk of 90-day mortality before liver resection. Preexisting renal disease and cirrhosis-related complications had the strongest influence on mortality. This score enables preoperative risk stratification, decision-making, quality assessment, and counseling for individual patients.

  14. Cost burden of type 2 diabetes in Germany: results from the population-based KORA studies

    PubMed Central

    Ulrich, Susanne; Holle, Rolf; Wacker, Margarethe; Stark, Renee; Icks, Andrea; Thorand, Barbara; Peters, Annette

    2016-01-01

    Objective To examine the impact of type 2 diabetes on direct and indirect costs and to describe the effect of relevant diabetes-related factors, such as type of treatment or glycaemic control on direct costs. Design Bottom-up excess cost analysis from a societal perspective based on population-based survey data. Participants 9160 observations from 6803 individuals aged 31–96 years (9.6% with type 2 diabetes) from the population-based KORA (Cooperative Health Research in the Region of Augsburg) studies in Southern Germany. Outcome measures Healthcare usage, productivity losses, and resulting direct and indirect costs. Methods Information on diabetes status, biomedical/sociodemographic variables, medical history and on healthcare usage and productivity losses was assessed in standardised interviews and examinations. Healthcare usage and productivity losses were costed with reference to unit prices and excess costs of type 2 diabetes were calculated using generalised linear models. Results Individuals with type 2 diabetes had 1.81 (95% CI 1.56 to 2.11) times higher direct (€3352 vs €1849) and 2.07 (1.51 to 2.84) times higher indirect (€4103 vs €1981) annual costs than those without diabetes. Cardiovascular complications, a long diabetes duration and treatment with insulin were significantly associated with increased direct costs; however, glycaemic control was only weakly insignificantly associated with costs. Conclusions This study illustrates the substantial direct and indirect societal cost burden of type 2 diabetes in Germany. Strong effort is needed to optimise care to avoid progression of the disease and costly complications. PMID:27872118

  15. A Nationwide Population-Based Cohort Study of Migraine and Organic-Psychogenic Erectile Dysfunction

    PubMed Central

    Wu, Szu-Hsien; Chuang, Eric; Chuang, Tien-Yow; Lin, Cheng-Li; Lin, Ming-Chia; Yen, Der-Jen; Kao, Chia-Hung

    2016-01-01

    Abstract As chronic illnesses and chronic pain are related to erectile dysfunction (ED), migraine as a prevalent chronic disorder affecting lots of people all over the world may negatively affect quality of life as well as sexual function. However, a large-scale population-based study of erectile dysfunction and other different comorbidities in patients with migraine is quite limited. This cohort longitudinal study aimed to estimate the association between migraine and ED using a nationwide population-based database in Taiwan. The data used for this cohort study were retrieved from the Longitudinal Health Insurance Database 2000 in Taiwan. We identified 5015 patients with migraine and frequency matched 20,060 controls without migraine from 2000 to 2011. The occurrence of ED was followed up until the end of 2011. We used Cox proportional hazard regression models to analyze the risks of ED. The overall incidence of ED was 1.78-fold greater in the migraine cohort than in the comparison cohort (23.3 vs 10.5 per 10,000 person-years; 95% confidence interval [CI] = 1.31–2.41). Furthermore, patients with migraine were 1.75-fold more likely to develop organic ED (95% CI = 1.27–2.41) than were the comparison cohort. The migraine patients with anxiety had a 3.6-fold higher HR of having been diagnosed with ED than the comparison cohort without anxiety (95% CI, 2.10–6.18). The results support that patients with migraine have a higher incidence of being diagnosed with ED, particularly in the patient with the comorbidity of anxiety. PMID:26962838

  16. Correlation between systemic lupus erythematosus and malignancies: a cross-sectional population-based study.

    PubMed

    Azrielant, Shir; Tiosano, Shmuel; Watad, Abdulla; Mahroum, Naim; Whitby, Aaron; Comaneshter, Doron; Cohen, Arnon D; Amital, Howard

    2017-01-14

    Autoimmune conditions reflect dysregulation of the immune system; this may be of clinical significance in the development of several malignancies. Previous studies show an association between systemic lupus erythematosus (SLE) and the development of malignancies; however, their investigations into the development of specific malignancies are inconsistent, and their external validity may be questionable. The main objective of this study is to investigate the association between the presence of SLE and various malignancies, in a large-scale population-based study. Data for this study was collected from Clalit Health Services, the largest state-mandated health service organization in Israel. All adult members diagnosed with SLE were included (n = 5018) and their age and sex-matched controls (n = 25,090), creating a cross-sectional population-based study. Medical records of all subjects were analyzed for documentation of malignancies. Logistic regression models were built separately for each malignant condition, controlling for age, gender, BMI, smoking, and socioeconomic status. Diagnosis of malignancy (of any type) was more prevalent in the SLE population (odds ratio [OR] 3.35, 95% confidence interval [CI] 3.02-3.72). SLE diagnosis was also found to be independently associated with higher proportions of non-Hodgkin lymphoma (OR 3.02, 95% CI 2.72-3.33), Hodgkin lymphoma (OR 2.43, 95% CI 1.88-2.99), multiple myeloma (OR 2.57, 95% CI 1.85-3.28), cervix uteri malignancies (OR 1.65, 95% CI 1.10-2.20), and genital organ malignancies (OR 2.32, 95% CI 1.42-3.22), after adjustment for confounding variables. The presence of an SLE diagnosis was found to be independently associated with higher proportions of malignancies, particularly hematologic malignancies. These findings should be considered while treating SLE patients, and possibly supplement their screening routine.

  17. Non-invasive imaging of skin cancer with fluorescence lifetime imaging using two photon tomography

    NASA Astrophysics Data System (ADS)

    Patalay, Rakesh; Talbot, Clifford; Alexandrov, Yuriy; Munro, Ian; Breunig, Hans Georg; König, Karsten; Warren, Sean; Neil, Mark A. A.; French, Paul M. W.; Chu, Anthony; Stamp, Gordon W.; Dunsby, Christopher

    2011-07-01

    Multispectral fluorescence lifetime imaging (FLIM) using two photon microscopy as a non-invasive technique for the diagnosis of skin lesions is described. Skin contains fluorophores including elastin, keratin, collagen, FAD and NADH. This endogenous contrast allows tissue to be imaged without the addition of exogenous agents and allows the in vivo state of cells and tissues to be studied. A modified DermaInspect® multiphoton tomography system was used to excite autofluorescence at 760 nm in vivo and on freshly excised ex vivo tissue. This instrument simultaneously acquires fluorescence lifetime images in four spectral channels between 360-655 nm using time-correlated single photon counting and can also provide hyperspectral images. The multispectral fluorescence lifetime images were spatially segmented and binned to determine lifetimes for each cell by fitting to a double exponential lifetime model. A comparative analysis between the cellular lifetimes from different diagnoses demonstrates significant diagnostic potential.

  18. Estimating the personal cure rate of cancer patients using population-based grouped cancer survival data.

    PubMed

    Binbing Yu; Tiwari, Ram C; Feuer, Eric J

    2011-06-01

    Cancer patients are subject to multiple competing risks of death and may die from causes other than the cancer diagnosed. The probability of not dying from the cancer diagnosed, which is one of the patients' main concerns, is sometimes called the 'personal cure' rate. Two approaches of modelling competing-risk survival data, namely the cause-specific hazards approach and the mixture model approach, have been used to model competing-risk survival data. In this article, we first show the connection and differences between crude cause-specific survival in the presence of other causes and net survival in the absence of other causes. The mixture survival model is extended to population-based grouped survival data to estimate the personal cure rate. Using the colorectal cancer survival data from the Surveillance, Epidemiology and End Results Programme, we estimate the probabilities of dying from colorectal cancer, heart disease, and other causes by age at diagnosis, race and American Joint Committee on Cancer stage.

  19. On estimating mean lifetimes by a weighted sum of lifetime measurements

    NASA Astrophysics Data System (ADS)

    Prosper, Harrison Bertrand

    1987-10-01

    Given N lifetime measurements an estimate of the mean lifetime can be obtained from a weighted sum of these measurements. We derive exact expressions for the probability density function, the moment-generating function, and the cumulative distribution function for the weighted sum. We indicate how these results might be used in the estimation of particle lifetimes. The probability distribution function of Yost for the distribution of lifetime measurements with finite measurement error is our starting point.

  20. Aspects of silicon bulk lifetimes

    NASA Technical Reports Server (NTRS)

    Landsberg, P. T.

    1985-01-01

    The best lifetimes attained for bulk crytalline silicon as a function of doping concentrations are analyzed. It is assumed that the dopants which set the Fermi level do not contribute to the recombination traffic which is due to the unknown defect. This defect is assumed to have two charge states: neutral and negative, the neutral defect concentration is frozen-in at some temperature T sub f. The higher doping concentrations should include the band-band Auger effect by using a generalization of the Shockley-Read-Hall (SRH) mechanism. The generalization of the SRH mechanism is discussed. This formulation gives a straightforward procedure for incorporating both band-band and band-trap Auger effects in the SRH procedure. Two related questions arise in this context: (1) it may sometimes be useful to write the steady-state occupation probability of the traps implied by SRH procedure in a form which approximates to the Fermi-Dirac distribution; and (2) the effect on the SRH mechanism of spreading N sub t levels at one energy uniformly over a range of energies is discussed.

  1. Lifetime Evolution of UV Jets

    NASA Technical Reports Server (NTRS)

    Corti, G.; Poletto, G.; Suess, S. T.; Moore, R.; Sterling, A.

    2006-01-01

    We report on observations acquired in May 2003 during a SOHO-Ulysses quadrature campaign. From May 25 to May 28, the SoHO LASCO Coronal Mass Ejection (CME) catalog lists a number of events which might have been observed by SOHO/UVCS, whose slit was centered along the Ulysses direction. However, because of time gaps in the observing schedule, or because of the unfavorable position of some CMEs, the most interesting events recorded by UVCS were a few short-lived ejections that represent the extension at higher altitudes of recursive EIT jets. We focus on jets occurring on May 26/27, visible also in EIT and LASCO images, which seem to propagate along the radial to Ulysses. UVCS spectra at 1.7 Rsun showed an unusually high emission in cool lines, lasting for about 10 to 25 minutes, with no evidence of hot plasma. Analysis of the cool line emission allowed us to infer the evolution of physical parameters during the jets lifetime and derive a crude estimate of the energy needed to account for their properties. We also looked for any evidence of the event in in situ data. Whether UVCS is observing jets or narrow CMEs is discussed in the contest of previous works on these classes of events and, in the last Section, we propose a scenario that accounts for our observations.

  2. Cosmology in Mr. Tompkins' Lifetime

    NASA Astrophysics Data System (ADS)

    Lindner, Rudi Paul

    2016-01-01

    Mr. Tompkins, the hero of George Gamow's most famous book, was born in the first decade of the twentieth century and lived until its end. A bank clerk by day, Mr. Tompkins had wide-ranging interests, and his curiosity led him to popular scientific presentations, and these in turn brought him a long and happy marriage to Maud, the daughter of a professor of physics. His lifetime offers an appropriate framework for a meditation on the history of cosmology during the century in which cosmology became a scientific enterprise. As it happens, Mr. Tompkins' first exposure to cosmology, in which he observed both the expansion and contraction of an oscillating universe in 1939, happened during the long night of relativity, the generation in which relativity specialists became few and, like the galaxies, far between. This talk will consider the heyday of early relativistic cosmology from 1917 to 1935, the causes and consequences of the "long night" from 1935 until 1963, and the renaissance of cosmology, which, occurring as it did upon the retirement of Mr. Tompkins, afforded him great pleasure in his later years.

  3. Lifetime Sports in Pennsylvania. A Position Paper.

    ERIC Educational Resources Information Center

    Pennsylvania State Dept. of Education, Harrisburg. Bureau of Curriculum Services.

    This document describes "lifetime sports" education in Pennsylvania. "Lifetime sports" is defined as individual and dual sports that increase energy expenditure and contribute to personal fitness so that people can safely pursue them throughout their life. The historical background is given for the specific program in…

  4. Recent measurements of the B hadron lifetime

    SciTech Connect

    Ong, R.A.

    1987-12-01

    Recent measurements of the B hadron lifetime from PEP and PETRA experiments are presented. These measurements firmly establish that the B lifetime is long (approx.1 psec), implying that the mixing between the third generation of quarks and the lighter quarks is much weaker that the mixing between the first two generations.

  5. Indices of Lifetime Polydrug Use among Adolescents

    ERIC Educational Resources Information Center

    Sneed, Carl D.; Morisky, Donald E.; Rotheram-Borus, Mary Jane; Lee, Sung-Jae; Ebin, V. J. Vicki J.

    2004-01-01

    The functional equivalency for three indices of lifetime polydrug use was examined in a sample of adolescents (N=794). The following indices were included in analyses: (a) a count of lifetime self-report of substances used; (b) an index weighted by the severity of the substances used; and (c) a hierarchical index of substance use. Analyses for…

  6. Multimodel Estimates of Atmospheric Lifetimes of Long-lived Ozone-Depleting Substances: Present and Future

    NASA Technical Reports Server (NTRS)

    Chipperfield, M. P.; Liang, Q.; Strahan, S. E.; Morgenstern, O.; Dhomse, S. S.; Abraham, N. L.; Archibald, A. T.; Bekki, S.; Braesicke, P.; Di Genova, G.; Fleming, E. L.; Hardiman, S. C.; Iachetti, D.; Jackman, C. H.; Kinnison, D. E.; Marchand, M.; Pitari, G.; Pyle, J. A.; Rozanov, E.; Stenke, A.; Tummon, F.

    2014-01-01

    We have diagnosed the lifetimes of long-lived source gases emitted at the surface and removed in the stratosphere using six three-dimensional chemistry-climate models and a two-dimensional model. The models all used the same standard photochemical data. We investigate the effect of different definitions of lifetimes, including running the models with both mixing ratio (MBC) and flux (FBC) boundary conditions. Within the same model, the lifetimes diagnosed by different methods agree very well. Using FBCs versus MBCs leads to a different tracer burden as the implied lifetime contained in the MBC value does not necessarily match a model's own calculated lifetime. In general, there are much larger differences in the lifetimes calculated by different models, the main causes of which are variations in the modeled rates of ascent and horizontal mixing in the tropical midlower stratosphere. The model runs have been used to compute instantaneous and steady state lifetimes. For chlorofluorocarbons (CFCs) their atmospheric distribution was far from steady state in their growth phase through to the 1980s, and the diagnosed instantaneous lifetime is accordingly much longer. Following the cessation of emissions, the resulting decay of CFCs is much closer to steady state. For 2100 conditions the model circulation speeds generally increase, but a thicker ozone layer due to recovery and climate change reduces photolysis rates. These effects compensate so the net impact on modeled lifetimes is small. For future assessments of stratospheric ozone, use of FBCs would allow a consistent balance between rate of CFC removal and model circulation rate

  7. Effects of Low Activity Solar Cycle on Orbital Debris Lifetime

    NASA Technical Reports Server (NTRS)

    Cable, Samual B.; Sutton, Eric K.; Lin, chin S.; Liou, J.-C.

    2011-01-01

    Long duration of low solar activity in the last solar minimum has an undesirable consequence of extending the lifetime of orbital debris. The AFRL TacSat-2 satellite decommissioned in 2008 has finally re-entered into the atmosphere on February 5th after more than one year overdue. Concerning its demise we have monitored its orbital decay and monthly forecasted Tacsat-2 re-entry since September 2010 by using the Orbital Element Prediction (OEP) model developed by the AFRL Orbital Drag Environment program. The model combines estimates of future solar activity with neutral density models, drag coefficient models, and an orbit propagator to predict satellite lifetime. We run the OEP model with solar indices forecast by the NASA Marshall Solar Activity Future Estimation model, and neutral density forecast by the MSIS-00 neutral density model. Based on the two line elements in 2010 up to mid September, we estimated at a 50% confidence level TacSat-2's re-entry time to be in early February 2011, which turned out to be in good agreement with Tacsat-2's actual re-entry date. The potential space weather effects of the coming low activity solar cycle on satellite lifetime and orbital debris population are examined. The NASA long-term orbital debris evolutionary model, LEGEND, is used to quantify the effects of solar flux on the orbital debris population in the 200-600 km altitude environment. The results are discussed for developing satellite orbital drag application product.

  8. Materials analysis using positron beam lifetime spectroscopy

    SciTech Connect

    Hartley, J.; Howell, R. H., Asoka-Kumar, P.; Sterne, P.; Stoeffl, W.

    1998-11-12

    We are using a defect analysis capabilities based on two positron beam lifetime spectrometers: the first is based on a 3 MeV electrostatic accelerator and the second on our high current linac beam. The high energy beam lifetime spectrometer is routinely used to perform positron lifetime analysis with a 3 MeV positron beam on thick sample specimens. It is being used for bulk sample analysis and analysis of samples encapsulated in controlled environments for in situ measurements. A second, low energy, microscopically focused, pulsed positron beam for defect analysis by positron lifetime spectroscopy is under development at the LLNL high current positron source. This beam will enable defect-specific, 3-dimensional maps of defect concentration with sub-micron location resolution. When coupled with first principles calculations of defect specific positron lifetimes it will enable new levels of defect concentration mapping and defect identification.

  9. Predictors of Colorectal Cancer Survival in Golestan, Iran: A Population-based Study

    PubMed Central

    Aryaie, Mohammad; Roshandel, Gholamreza; Semnani, Shahryar; Asadi-Lari, Mohsen; Aarabi, Mohsen; Vakili, Mohammad Ali; Kazemnejhad, Vahideh; Sedaghat, Seyed Mehdi

    2013-01-01

    OBJECTIVES We aimed to investigate factors associated with colorectal cancer survival in Golestan, Iran. METHODS We used a population based cancer registry to recruit study subjects. All patients registered since 2004 were contacted and data were collected using structured questionnaires and trained interviewers. All the existing evidences to determine the stage of the cancer were also collected. The time from first diagnosis to death was compared in patients according to their stage of cancer using the Kaplan-Meir method. A Cox proportional hazard model was built to examine their survival experience by taking into account other covariates. RESULTS Out of a total of 345 subjects, 227 were traced. Median age of the subjects was 54 and more than 42% were under 50 years old. We found 132 deaths among these patients, 5 of which were non-colorectal related deaths. The median survival time for the entire cohort was 3.56 years. A borderline significant difference in survival experience was detected for ethnicity (log rank test, p=0.053). Using Cox proportional hazard modeling, only cancer stage remained significantly associated with time of death in the final model. CONCLUSIONS Colorectal cancer occurs at a younger age among people living in Golestan province. A very young age at presentation and what appears to be a high proportion of patients presenting with late stage in this area suggest this population might benefit substantially from early diagnoses by introducing age adapted screening programs. PMID:23807907

  10. The lifetime of axion stars

    NASA Astrophysics Data System (ADS)

    Eby, Joshua; Suranyi, Peter; Wijewardhana, L. C. R.

    2016-05-01

    We investigate the decay of condensates of scalars in a field theory defined by V (𝒜) = m2f2[1 -cos(𝒜/f)], where m and f are the mass and decay constant of the scalar field. An example of such a theory is that of the axion, in which case the condensates are called axion stars. The axion field, 𝒜, is self-adjoint. As a result, the axion number is not an absolutely conserved quantity. Therefore, axion stars are not stable and have finite lifetimes. Bound axions, localized on the volume of the star, have a coordinate uncertainty δx ˜ R ˜ 1/(maΔ), where R is the radius of the star and Δ = 1 - E0 2/ma 2. Here ma and E0 are the mass, and the ground state energy of the bound axion. Then the momentum distribution of axions has a width of δp ˜ maΔ. At strong binding, Δ = 𝒪(1), bound axions can easily transfer a sufficient amount of momentum to create and emit a free axion, leading to fast decay of the star with a transition rate Γ ˜ ma. However, when Δ ≪ 1, the momentum distribution is more restricted, and as shown in this paper, the transition rate for creating a free axion decreases as exp(-pδx) ˜exp(-Δ-1). Then sufficiently large, weakly bound axion stars, produced after the Big Bang, survive until the present time. We plot the region of their stability, limited by decay through axion loss and by gravitational instability, as a function of the mass of the axion and the mass of the star.

  11. When to be skeptical of negative studies: pitfalls in evaluating occupational risks using population-based case-control studies.

    PubMed

    Hu, S W; Hertz-Picciotto, I; Siemiatycki, J

    1999-01-01

    This study investigated arsenic and lung cancer incidence in a community setting in the Montreal area. Job histories and sociodemographic factors were collected by interview from 857 lung cancer cases, 533 general population controls, and 1,360 controls with other cancers. Chemist-hygienists assessed each subject's life-time occupational exposure to 294 substances. Logistic regressions yielded arsenic/lung cancer odds ratios of 1.1 (95% confidence interval = 0.60, 1.7) based on cancer controls, and 0.82 (95% confidence interval = 0.41, 1.6) based on population controls. Risk did not rise with increasing level or probability of exposure. Worksite studies consistently show lung carcinogenicity from arsenic. Since confounding from other chemicals was well controlled, the most likely explanation is substantially lower exposures than in previous studies. The lack of association in this study demonstrates the need for caution in interpreting negative findings from population-based case-control studies, particularly when exposures are low or rare, as well as the difficulty in generating hypotheses from such studies.

  12. Photosensitizing agents and the risk of non-melanoma skin cancer: a population-based case-control study.

    PubMed

    Robinson, Sarah N; Zens, Michael S; Perry, Ann E; Spencer, Steven K; Duell, Eric J; Karagas, Margaret R

    2013-08-01

    It is well-known that UV light exposure and a sun-sensitive phenotype are risk factors for the development of non-melanoma skin cancer (NMSC), including basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). In this New Hampshire population-based case-control study, we collected data from 5,072 individuals, including histologically confirmed cases of BCC and SCC, and controls via a personal interview to investigate possible associations between photosensitizing medication use and NMSC. After adjustment for potentially confounding factors (e.g., lifetime number of painful sunburns), we found a modest increase in risk of SCC (odds ratio (OR)=1.2, 95% confidence interval (CI)=1.0-1.4) and BCC (OR=1.2, 95% CI=0.9-1.5), in particular early-onset BCC, (≤ 50 years of age) (OR=1.5, 95% CI=1.1-2.1) associated with photosensitizing medication use. For SCC the association was strongest among those with tendency to sunburn rather than tan. We also specifically found associations with BCC, and especially early-onset BCC, and photosensitizing antimicrobials. In conclusion, certain commonly prescribed photosensitizing medications may enhance the risk of developing SCC, especially in individuals with a sun-sensitive phenotype, and may increase the risk of developing BCC and incidence of BCC at a younger age.

  13. The PACE study: lifetime and past-year prevalence of headache in Parma's adult general population.

    PubMed

    Taga, Arens; Russo, Marco; Manzoni, Gian Camillo; Torelli, Paola

    2017-02-17

    Headache is a widespread disorder and therefore it has a strong impact on quality of life. In the present work we focused on lifetime and past-year prevalence of headache in general and by gender, in a population-based sample in Parma. A total of 904 subjects representative of Parma's adult general population were interviewed face-to-face by a physician from the Parma Headache Centre, using a validated questionnaire. The lifetime prevalence of headache was 69.1%, i.e. 75.8% in women and 60.6% in men; the crude past-year prevalence of headache was 42.8%, i.e. 52.0% in women and 31.1% in men. Both lifetime and past-year prevalence rates were significantly higher in females than in males (odds ratio, respectively, 2.0 and 2.4). In our study, past-year prevalence decreased after age 50 in both genders. Most people suffer from one headache subtype. In over 80% of cases, headache starts before age 40 and therefore people were not very likely to develop headache after 50 years. The past-year and lifetime prevalence rate of headache in general that we found in our study falls within the lower range of values for headache prevalence in European countries. Further researches need to be set in the Italian epidemiological background.

  14. Passive-aggressive (negativistic) personality disorder: a population-based twin study.

    PubMed

    Czajkowski, Nikolai; Kendler, Kenneth S; Jacobson, Kristen C; Tambs, Kristian; Røysamb, Espen; Reichborn-Kjennerud, Ted

    2008-02-01

    The objective of this study was to investigate the familial aggregation of passive aggressive personality disorder (PAPD), and explore issues regarding PAPD raised by the DSM-IV Personality Disorder Work Group. Two thousand seven hundred and ninety-four Norwegian twins from the population-based Norwegian Institute of Public Health Twin Panel were interviewed with the Structured Interview for DSM-IV Personality (SIDP-IV). Because of the rarity of the twins meeting full diagnostic criteria for PAPD a dimensional representation of the disorder was used for the analyses. Overlap with other axis II disorders was assessed by polychoric correlations, while familial aggregation was explored by structural equation twin models. Overlap was highest with paranoid (r = 0.52) and borderline personality disorder (r = 0.53), and lowest with schizoid (r = 0.26). Significant familial aggregation was found for PAPD. The twin correlations and parameter estimates in the full model indicated genetic and shared environmental effects for females, and only shared environmental effects for males, but the prevalence of endorsed PAPD criteria in this community sample was too low to permit us to conclude with confidence regarding the relative influence of genetic and shared environmental factors on the familial aggregation of PAPD.

  15. Associations of childhood eczema severity: A US population based study

    PubMed Central

    Silverberg, Jonathan I.; Simpson, Eric L.

    2014-01-01

    Little is known about predictors of eczema severity in the US population. We sought to determine the distribution and associations of childhood eczema severity in the US. We analyzed data from the 2007 National Survey of Children's Health, a prospective questionnaire-based study of a nationally representative sample of 91,642 children (0-17yr). The prevalence of childhood eczema was 12.97% (95% confidence interval [95% CI]=12.42–13.53); 67.0% (95% CI: 64.8–69.2) had mild, 26.0% (95% CI: 23.9–28.1) moderate and 7.0% (95% CI: 5.8–8.3) severe disease. There was significant statewide-variation of the distribution of eczema severity (Rao-Scott chi square, P=0.004), with highest rates of severe disease in Northeastern and Midwestern states. In univariate models, eczema severity was increased with older age, African-American and Hispanic race/ethnicity, lower household income, oldest child in the family, home with a single mother, lower paternal/maternal education level, maternal general health, maternal/paternal emotional health, dilapidated housing and garbage on the streets. In multivariate survey logistic regression models using stepwise and backward selection, moderate–severe eczema was associated with older age, lower household income and fair or poor maternal health, but inversely associated with birthplace outside the US. These data indicate that environmental and/or lifestyle factors play an important role in eczema severity. PMID:24819283

  16. Propranolol Reduces Cancer Risk: A Population-Based Cohort Study.

    PubMed

    Chang, Ping-Ying; Huang, Wen-Yen; Lin, Cheng-Li; Huang, Tzu-Chuan; Wu, Yi-Ying; Chen, Jia-Hong; Kao, Chia-Hung

    2015-07-01

    β-Blockers have been reported to exhibit potential anticancer effects in cancer cell lines and animal models. However, clinical studies have yielded inconsistent results regarding cancer outcomes and cancer risk when β-blockers were used. This study investigated the association between propranolol and cancer risk.Between January 1, 2000 and December 31, 2011, a patient cohort was extracted from the Longitudinal Health Insurance Database 2000, a subset of the Taiwan National Health Insurance Research Database. A propranolol cohort (propranolol usage >6 months) and nonpropranolol cohort were matched using a propensity score. Cox proportional hazard models were used to estimate the hazard ratio (HR) and 95% confidence intervals (CIs) of cancer associated with propranolol treatment.The study sample comprised 24,238 patients. After a 12-year follow-up period, the cumulative incidence for developing cancer was low in the propranolol cohort (HR: 0.75; 95% CI: 0.67-0.85; P < 0.001). Patients with propranolol treatment exhibited significantly lower risks of cancers in head and neck (HR: 0.58; 95% CI: 0.35-0.95), esophagus (HR: 0.35; 95% CI: 0.13-0.96), stomach (HR: 0.54; 95% CI: 0.30-0.98), colon (HR: 0.68; 95% CI: 0.49-0.93), and prostate cancers (HR: 0.52; 95% CI: 0.33-0.83). The protective effect of propranolol for head and neck, stomach, colon, and prostate cancers was most substantial when exposure duration exceeded 1000 days.This study supports the proposition that propranolol can reduce the risk of head and neck, esophagus, stomach, colon, and prostate cancers. Further prospective study is necessary to confirm these findings.

  17. High speed multispectral fluorescence lifetime imaging.

    PubMed

    Fereidouni, Farzad; Reitsma, Keimpe; Gerritsen, Hans C

    2013-05-20

    We report a spectrally resolved fluorescence lifetime imaging system based on time gated single photon detection with a fixed gate width of 200 ps and 7 spectral channels. Time gated systems can operate at high count rates but usually have large gate widths and sample only part of the fluorescence decay curve. In the system presented in this work, the fluorescence signal is sampled using a high speed transceiver. An error analysis is carried out to characterize the performance of both lifetime and spectral detection. The effect of gate width and spectral channel width on the accuracy of estimated lifetimes and spectral widths is described. The performance of the whole instrument is evaluated at count rates of up to 12 MHz. Accurate fluorescence lifetimes (error < 2%) are recorded at count rates as high as 5 MHz. This is limited by the PMT performance, not by the electronics. Analysis of the large spectral lifetime image sets is challenging and time-consuming. Here, we demonstrate the use of lifetime and spectral phasors for analyzing images of fibroblast cells with 2 different labeled components. The phasor approach provides a fast and intuitive way of analyzing the results of spectrally resolved fluorescence lifetime imaging experiments.

  18. Lifetime Measurements and Deformation in ^79Sr

    NASA Astrophysics Data System (ADS)

    Ryu, Y. K.; Kaye, R. A.; Arora, S. R.; Tabor, S. L.; Baldwin, T.; Campbell, D. B.; Chandler, C.; Cooper, M. W.; Hoffman, C. R.; Pavan, J.; Wiedeking, M.; D"Oring, J.; Sun, Y.; Gerbick, S. M.; Grubor-Urosevic, O.; Riley, L. A.

    2006-10-01

    High-spin states in ^79Sr were produced following the ^54Fe(^28Si, 2pn) fusion-evaporation reaction using a beam energy of 90 MeV at the Florida State University (FSU) Tandem-Linac facility, and the resulting de-exciting γ rays were detected with the FSU Ge array of 10 Compton-suppressed detectors. The ^54Fe target was thick enough so that all of the synthesized nuclei could stop completely in the target, resulting in Doppler-shifted γ-ray line shapes that could be analyzed using the Doppler-shift attenuation method. In all, 23 lifetimes were measured in three separate band structures using this method, and then used to infer transition quadrupole moments (Qt) and quadrupole deformations (β2) using the rotational model. The results show good qualitative agreement with the predictions of both cranked Woods-Saxon (CWS) and projected shell model (PSM) calculations. The band based on a d5/2 single-particle orbit, verified in this study through γ- γ coincidences, intensity measurements, and directional correlation of oriented nuclei (DCO) ratios, was found to have the largest average deformation (β2,ave= 0.41) among the three bands, in agreement with the CWS and PSM predictions. Supported in part by the NSF and the OWU SSRP.

  19. Lifetime Measurements and Deformation in ^79Sr

    NASA Astrophysics Data System (ADS)

    Ryu, Y. K.; Kaye, R. A.; Arora, S. R.; Tabor, S. L.; Baldwin, T.; Campbell, D. B.; Chandler, C.; Cooper, M. W.; Hoffman, C. R.; Pavan, J.; Wiedeking, M.; D"Oring, J.; Sun, Y.; Gerbick, S. M.; Grubor-Urosevic, O.; Riley, L. A.

    2006-10-01

    High-spin states in ^79Sr were produced following the ^54Fe(^28Si, 2pn) fusion-evaporation reaction using a beam energy of 90 MeV at the Florida State University (FSU) Tandem-Linac facility, and the resulting de-exciting γ rays were detected with the FSU Ge array of 10 Compton-suppressed detectors. The ^54Fe target was thick enough so that all of the synthesized nuclei could stop completely in the target, resulting in Doppler-shifted γ-ray line shapes that could be analyzed using the Doppler-shift attenuation method. In all, 23 lifetimes were measured in three separate band structures using this method, and then used to infer transition quadrupole moments (Qt) and quadrupole deformations (β2) using the rotational model. The results show good qualitative agreement with the predictions of both cranked Woods-Saxon (CWS) and projected shell model (PSM) calculations. The band based on a d5/2 single-particle orbit, verified in this study through γ- γ coincidences, intensity measurements, and directional correlation of oriented nuclei (DCO) ratios, was found to have the largest average deformation (β2,ave = 0.41) among the three bands, in agreement with the CWS and PSM predictions.

  20. Measurement of Rydberg positronium fluorescence lifetimes

    NASA Astrophysics Data System (ADS)

    Deller, A.; Alonso, A. M.; Cooper, B. S.; Hogan, S. D.; Cassidy, D. B.

    2016-06-01

    We report measurements of the fluorescence lifetimes of positronium (Ps) atoms with principal quantum numbers n =10 -19 . Ps atoms in Rydberg-Stark states were produced via a two-color two-step 1 3S→2 3P→n 3S/n lifetimes of the Rydberg levels, yielding values ranging from 3 μ s to 26 μ s . Our data are in accord with the expected radiative lifetimes of Rydberg-Stark states of Ps.

  1. Lifetimes of Electrodes for AMTEC Cells

    NASA Technical Reports Server (NTRS)

    Ryan, M. A.; Kisor, A.; Williams, R F.; Jeffries-Nakamura, B.; O'Connor, D.

    1994-01-01

    The lifetime of an AMTEC electrode depends on the rate of grain growth, which in turn depends on the surface self-diffusion coefficient of the electrode material under AMTEC operating conditions. Grain growth rates for molybdenum and platinum-tungsten alloy electrodes have been determined, and have been used to predict operating lifetimes of AMTEC electrodes. For lifetimes of 10 years of more, Mo may be used in AMTEC cells only at operating temperatures under 1100 K. Pt(sub 2.5)W electrodes may be used at much higher temperatures, up to 1300 K.

  2. Family of lifetime sensors for medical purposes

    NASA Astrophysics Data System (ADS)

    Lippitsch, Max E.; Draxler, Sonja

    1995-05-01

    A family of indicators has been developed for fluorescence lifetime-based measurement of oxygen, pH, carbon dioxide, and potassium, all the indicators being derivatives of the same chemical compound and having identical spectral and lifetime properties. The indicators show an absorption accessible to low- cast light sources, a large Stokes shift, and long fluorescence decay time. all indicators can be excited at the same excitation wavelength, monitored at the same emission wavelength, and measured within the same time range. This opens the possibility of building a compact lifetime-based instrument to simultaneously measure blood gases and cations.

  3. Health Literacy in Taiwan: A Population-Based Study.

    PubMed

    Duong, Van Tuyen; Lin, I-Feng; Sorensen, Kristine; Pelikan, Jürgen M; Van Den Broucke, Stephan; Lin, Ying-Chin; Chang, Peter Wushou

    2015-11-01

    Data on health literacy (HL) in the population is limited for Asian countries. This study aimed to test the validity of the Mandarin version of the European Health Literacy Survey Questionnaire (HLS-EU-Q) for use in the general public in Taiwan. Multistage stratification random sampling resulted in a sample of 2989 people aged 15 years and above. The HLS-EU-Q was validated by confirmatory factor analysis with excellent model data fit indices. The general HL of the Taiwanese population was 34.4 ± 6.6 on a scale of 50. Multivariate regression analysis showed that higher general HL is significantly associated with the higher ability to pay for medication, higher self-perceived social status, higher frequency of watching health-related TV, and community involvement but associated with younger age. HL is also associated with health status, health behaviors, and health care accessibility and use. The HLS-EU-Q was found to be a useful tool to assess HL and its associated factors in the general population.

  4. A Population Based Twin Study of DSM-5 Maladaptive Personality Domains.

    PubMed

    South, Susan C; Krueger, Robert F; Knudsen, Gun Peggy; Ystrom, Eivind; Czajkowski, Nikolai; Aggen, Steven H; Neale, Michael C; Gillespie, Nathan A; Kendler, Kenneth S; Reichborn-Kjennerud, Ted

    2016-10-31

    Personality disorders (PDs) can be partly captured by dimensional traits, a viewpoint reflected in the most recent Diagnostic and Statistical Manual of Mental Disorders-Fifth Edition (DSM-5) Alternative (Section III) Model for PD classification. The current study adds to the literature on the Alternative Model by examining the magnitude of genetic and environmental influences on 6 domains of maladaptive personality: negative emotionality, detachment, antagonism, disinhibition, compulsivity, and psychoticism. In a large, population-based sample (N = 2,293) of Norwegian male and female twin pairs, we investigated (a) if the domains demonstrated measurement invariance across gender at the phenotypic level, meaning that the relationships between the items and the latent factor were equivalent in men and women; and (b) if genetic and environmental influences on variation in these domains were equivalent across gender. Multiple group confirmatory factor modeling provided evidence that all 6 domain scale measurement models were gender-invariant. The best fitting biometric model for 4 of the 6 domains (negative emotionality, detachment, disinhibition, and compulsivity) was one in which genetic and environmental influences could be set invariant across gender. Evidence for sex differences in psychoticism was mixed, but the only clear evidence for quantitative sex differences was for the antagonism scale, with greater genetic influences found for men than women. Genetic influences across domains were moderate overall (19-37%), in line with previous research using symptom-based measures of PDs. This study adds to the very limited knowledge currently existing on the etiology of maladaptive personality traits. (PsycINFO Database Record

  5. Public assistance, drug testing, and the law: the limits of population-based legal analysis.

    PubMed

    Player, Candice T

    2014-01-01

    In Populations, Public Health and the Law, legal scholar Wendy Parmet urges courts to embrace population-based legal analysis, a public health inspired approach to legal reasoning. Parmet contends that population-based legal analysis offers a way to analyze legal issues--not unlike law and economics--as well as a set of values from which to critique contemporary legal discourse. Population-based analysis has been warmly embraced by the health law community as a bold new way of analyzing legal issues. Still, population-based analysis is not without its problems. At times, Parmet claims too much territory for the population perspective. Moreover, Parmet urges courts to recognize population health as an important norm in legal reasoning. What should we do when the insights of public health and conventional legal reasoning conflict? Still in its infancy, population-based analysis offers little in the way of answers to these questions. This Article applies population-based legal analysis to the constitutional problems that arise when states condition public assistance benefits on passing a drug test, thereby highlighting the strengths of the population perspective and exposing its weaknesses.

  6. Assessing the Validity of a Stage Measure on Physical Activity in a Population-Based Sample of Individuals with Type 1 or Type 2 Diabetes

    ERIC Educational Resources Information Center

    Plotnikoff, Ronald C.; Lippke, Sonia; Reinbold-Matthews, Melissa; Courneya, Kerry S.; Karunamuni, Nandini; Sigal, Ronald J.; Birkett, Nicholas

    2007-01-01

    This study was designed to test the validity of a transtheoretical model's physical activity (PA) stage measure with intention and different intensities of behavior in a large population-based sample of adults living with diabetes (Type 1 diabetes, n = 697; Type 2 diabetes, n = 1,614) and examine different age groups. The overall…

  7. Topological lifetimes of polydisperse colloidal hard spheres at a wall

    NASA Astrophysics Data System (ADS)

    Dullens, Roel P. A.; Kegel, Willem K.

    2005-01-01

    Confocal scanning laser microscopy was used to study the behavior of dense suspensions of model colloidal hard spheres at a single wall. Due to the slight polydispersity, our system shows a reentrant melting transition at high densities involving a hexatic structure [R. P. A. Dullens and W. K. Kegel, Phys. Rev. Lett 92, 195702 (2004)]. The reentrant melting transition is accompanied by an increase in the mean-squared displacement. The correlation between structure and dynamics was quantitatively analyzed on a single-particle level. In particular, the topological lifetime, being the average time that a particle spends having the same coordination number, is determined for all coordination numbers and as a function of volume fraction. The defective (non-sixfold-coordinated) particles exhibit shorter lifetimes than sixfold-coordinated particles, indicating that the mobility of the system is larger at or close to defective particles. The lifetime itself is a strong function of volume fraction. In particular, the global behavior of the mean-squared displacement is proportional to the hopping frequency (the inverse of the lifetime), showing that particles changing their coordination number contribute most to the local mobility.

  8. Monitoring photosensitizer uptake using two photon fluorescence lifetime imaging microscopy.

    PubMed

    Yeh, Shu-Chi Allison; Diamond, Kevin R; Patterson, Michael S; Nie, Zhaojun; Hayward, Joseph E; Fang, Qiyin

    2012-01-01

    Photodynamic Therapy (PDT) provides an opportunity for treatment of various invasive tumors by the use of a cancer targeting photosensitizing agent and light of specific wavelengths. However, real-time monitoring of drug localization is desirable because the induction of the phototoxic effect relies on interplay between the dosage of localized drug and light. Fluorescence emission in PDT may be used to monitor the uptake process but fluorescence intensity is subject to variability due to scattering and absorption; the addition of fluorescence lifetime may be beneficial to probe site-specific drug-molecular interactions and cell damage. We investigated the fluorescence lifetime changes of Photofrin(®) at various intracellular components in the Mat-LyLu (MLL) cell line. The fluorescence decays were analyzed using a bi-exponential model, followed by segmentation analysis of lifetime parameters. When Photofrin(®) was localized at the cell membrane, the slow lifetime component was found to be significantly shorter (4.3 ± 0.5 ns) compared to those at other locations (cytoplasm: 7.3 ± 0.3 ns; mitochondria: 7.0 ± 0.2 ns, p < 0.05).

  9. The lifetime of electronic excitations in metal clusters

    NASA Astrophysics Data System (ADS)

    Quijada, M.; Díez Muiño, R.; Echenique, P. M.

    2005-05-01

    Density functional theory and the self-energy formalism are used to evaluate the lifetime of electronic excitations in metal clusters of nanometre size. The electronic structure of the cluster is obtained in the jellium model and spherical symmetry is assumed. Two effects that depend on the size of the clusters are discussed: the change in the number of final states to which the excitation can decay, and the modification in the screened interaction between electrons. For clusters with density parameter rs = 4 and diameter a few nanometres, a lifetime value of {\\approx }5 fs is reached for electronic excitations of {\\approx }1 eV. This value is of the same order of magnitude of that obtained in the bulk limit at the same level of approximation. For smaller clusters, a distinct non-monotonic behaviour of the lifetime as a function of the cluster size is found and the lifetime of excitations of {\\approx }1 eV can vary between 4 and 30 fs.

  10. Lifetimes of Stratospheric Ozone-Depleting Substances, Their Replacements, and Related Species

    NASA Astrophysics Data System (ADS)

    Newman, P. A.; Ko, M. K.; Reimann, S.; Strahan, S. E.; Atlas, E. L.; Burkholder, J. B.; Chipperfield, M.; Engel, A.; Liang, Q.; Plumb, R. A.; Stolarski, R. S.

    2013-12-01

    Estimating the average lifetime of a chemical in the atmosphere is crucial to understanding its current and future atmospheric concentration. Furthermore, for both ozone depleting substances (ODSs) and greenhouse gases, information on their lifetimes is of paramount importance for obtaining future estimates for ozone depletion and climate forcing. The 'Lifetimes of Stratospheric Ozone-Depleting Substances, Their Replacements, and Related Species', under the World Climate Research Programme/Stratospheric Processes And their Role in Climate project, was completed in August 2013. The goal was to estimate both lifetimes and uncertainties. In this presentation we will provide: 1) an overview of key aspects of the definitions of lifetimes, 2) discuss the extensively revised photochemical values and uncertainties for obtaining lifetimes, 3) show new observational and 4) modeling estimates of lifetimes, and finally, 5) show new recommendations for the steady-state atmospheric lifetimes of 27 long-lived species. New findings include: * New chemical kinetic and photochemical information on the uncertainties associated with the Lyman-a absorption cross-sections, and revisions of absorption cross-section parameterizations for several chlorofluorocarbons. * State-of-the-art chemistry-climate models (CCMs) were used to estimate lifetimes over the course of the 21st century. Projected increases of the Brewer-Dobson circulation suggest that lifetimes should be shorter during the 21st century. However, the recovery of ozone in the CCMs shows that the photolysis of many species will decline, yielding only small changes in lifetimes of most species * The CFC-11 recommended lifetime increases to 52 years from the WMO (2011) value of 45 years. The most likely range is narrowed to 43-67 years. * The 44 year steady-state lifetime of CCl4 due to atmospheric loss determined in this report is substantially longer than the 35 years from WMO (2011). However, inclusion of the land and ocean

  11. Explaining lifetime criminal arrests among clients of a psychiatric probation and parole service.

    PubMed

    Solomon, P; Draine, J

    1999-01-01

    This study examines the extent to which sociodemographic characteristics, clinical characteristics, substance abuse problems, and the array of lifetime criminal behavior may explain lifetime arrests among offenders supervised by the psychiatric probation and parole service. Three hundred twenty-five clients with new cases at a psychiatric probation and parole service in a large urban center were screened for major psychiatric disorders. They were also interviewed for socio-demographic characteristics, mental health treatment history, criminal behavior, and arrest history. Hierarchical block multiple regression analysis tested a model explaining lifetime arrests. After controlling for age and other demographic variables, the number of lifetime psychiatric hospitalizations and lifetime occurrences of mania diagnosis significantly explained lifetime arrests. The total model explained about 10 percent of the variance in lifetime arrests after controlling for opportunity variables, which explained 45 percent. The explanatory power of lifetime hospitalizations and mania support the contention that symptoms, rather than diagnosis, may be the most important clinical factor in explaining criminal arrest among persons with mental illness. Implications for psychiatric services include the development of effective jail diversion programs.

  12. Temperature Compensation of Oxygen Sensing Films Utilizing a Dynamic Dual Lifetime Calculation Technique

    PubMed Central

    Collier, Bradley B.; McShane, Michael J.

    2014-01-01

    With advances to chemical sensing, methods for compensation of errors introduced by interfering analytes are needed. In this work, a dual lifetime calculation technique was developed to enable simultaneous monitoring of two luminescence decays. Utilizing a windowed time-domain luminescence approach, the response of two luminophores is separated temporally. The ability of the dual dynamic rapid lifetime determination (DDRLD) approach to determine the response of two luminophores simultaneously was investigated through mathematical modeling and experimental testing. Modeling results indicated that lifetime predictions will be most accurate when the ratio of the lifetimes from each luminophore is at least three and the ratio of intensities is near unity. In vitro experiments were performed using a porphyrin that is sensitive to both oxygen and temperature, combined with a temperature-sensitive inorganic phosphor used for compensation of the porphyrin response. In static experiments, the dual measurements were found to be highly accurate when compared to single-luminophore measurements—statistically equivalent for the long lifetime emission and an average difference of 2% for the short lifetimes. Real-time testing with dynamic windowing was successful in demonstrating dual lifetime measurements and temperature compensation of the oxygen sensitive dye. When comparing the actual oxygen and temperature values with predictions made using a dual calibration approach, an overall difference of less than 1% was obtained. Thus, this method enables rapid, accurate extraction of multiple lifetimes without requiring computationally intense curve fitting, providing a significant advancement toward multi-analyte sensing and imaging techniques. PMID:26566384

  13. Ambient Fine Particulate Matter and Mortality among Survivors of Myocardial Infarction: Population-Based Cohort Study

    PubMed Central

    Chen, Hong; Burnett, Richard T.; Copes, Ray; Kwong, Jeffrey C.; Villeneuve, Paul J.; Goldberg, Mark S.; Brook, Robert D.; van Donkelaar, Aaron; Jerrett, Michael; Martin, Randall V.; Brook, Jeffrey R.; Kopp, Alexander; Tu, Jack V.

    2016-01-01

    Background: Survivors of acute myocardial infarction (AMI) are at increased risk of dying within several hours to days following exposure to elevated levels of ambient air pollution. Little is known, however, about the influence of long-term (months to years) air pollution exposure on survival after AMI. Objective: We conducted a population-based cohort study to determine the impact of long-term exposure to fine particulate matter ≤ 2.5 μm in diameter (PM2.5) on post-AMI survival. Methods: We assembled a cohort of 8,873 AMI patients who were admitted to 1 of 86 hospital corporations across Ontario, Canada in 1999–2001. Mortality follow-up for this cohort extended through 2011. Cumulative time-weighted exposures to PM2.5 were derived from satellite observations based on participants’ annual residences during follow-up. We used standard and multilevel spatial random-effects Cox proportional hazards models and adjusted for potential confounders. Results: Between 1999 and 2011, we identified 4,016 nonaccidental deaths, of which 2,147 were from any cardiovascular disease, 1,650 from ischemic heart disease, and 675 from AMI. For each 10-μg/m3 increase in PM2.5, the adjusted hazard ratio (HR10) of nonaccidental mortality was 1.22 [95% confidence interval (CI): 1.03, 1.45]. The association with PM2.5 was robust to sensitivity analyses and appeared stronger for cardiovascular-related mortality: ischemic heart (HR10 = 1.43; 95% CI: 1.12, 1.83) and AMI (HR10 = 1.64; 95% CI: 1.13, 2.40). We estimated that 12.4% of nonaccidental deaths (or 497 deaths) could have been averted if the lowest measured concentration in an urban area (4 μg/m3) had been achieved at all locations over the course of the study. Conclusions: Long-term air pollution exposure adversely affects the survival of AMI patients. Citation: Chen H, Burnett RT, Copes R, Kwong JC, Villeneuve PJ, Goldberg MS, Brook RD, van Donkelaar A, Jerrett M, Martin RV, Brook JR, Kopp A, Tu JV. 2016. Ambient fine

  14. Method of processing positron lifetime spectra

    SciTech Connect

    Valuev, N.P.; Klimov, A.B.; Zhikharev, A.N.

    1985-05-01

    This paper describes a method for the processing of spectra of positron annihilation which permits a much more relaible determination of the lifetime during numerical processing of spectra by computer.

  15. Physical Trauma and Amyotrophic Lateral Sclerosis: A Population-Based Study Using Danish National Registries

    PubMed Central

    Seals, Ryan M.; Hansen, Johnni; Gredal, Ole; Weisskopf, Marc G.

    2016-01-01

    Prior studies have suggested that physical trauma might be associated with the development of amyotrophic lateral sclerosis (ALS). We conducted a population-based, individually matched case-control study in Denmark to assess whether hospitalization for trauma is associated with a higher risk of developing ALS. There were 3,650 incident cases of ALS in the Danish National Patient Register from 1982 to 2009. We used risk-set sampling to match each case to 100 age- and sex-matched population controls alive on the date of the case's diagnosis. Odds ratios and 95% confidence intervals were calculated using a conditional logistic regression model. History of trauma diagnosis was also obtained from the Danish Patient Register. When traumas in the 5 years prior to the index date were excluded, there was a borderline association between any trauma and ALS (odds ratio (OR) = 1.09, 95% confidence interval (CI): 0.99, 1.19). A first trauma before age 55 years was associated with ALS (OR = 1.22, 95% CI: 1.08, 1.37), whereas first traumas at older ages were not (OR = 0.97, 95% CI: 0.85, 1.10). Our data suggest that physical trauma at earlier ages is associated with ALS risk. Age at first trauma could help explain discrepancies in results of past studies of trauma and ALS. PMID:26825926

  16. Cognitive functioning in children with internalising, externalising and dysregulation problems: a population-based study.

    PubMed

    Blanken, Laura M E; White, Tonya; Mous, Sabine E; Basten, Maartje; Muetzel, Ryan L; Jaddoe, Vincent W V; Wals, Marjolein; van der Ende, Jan; Verhulst, Frank C; Tiemeier, Henning

    2017-04-01

    Psychiatric symptoms in childhood are closely related to neurocognitive deficits. However, it is unclear whether internalising and externalising symptoms are associated with general or distinct cognitive problems. We examined the relation between different types of psychiatric symptoms and neurocognitive functioning in a population-based sample of 1177 school-aged children. Internalising and externalising behaviour was studied both continuously and categorically. For continuous, variable-centred analyses, broadband scores of internalising and externalising symptoms were used. However, these measures are strongly correlated, which may prevent identification of distinct cognitive patterns. To distinguish groups of children with relatively homogeneous symptom patterns, a latent profile analysis of symptoms at age 6 yielded four exclusive groups of children: a class of children with predominantly internalising symptoms, a class with externalising symptoms, a class with co-occurring internalising and externalising symptoms, that resembles the CBCL dysregulation profile and a class with no problems. Five domains of neurocognitive ability were tested: attention/executive functioning, language, memory and learning, sensorimotor functioning, and visuospatial processing. Consistently, these two different modelling approaches demonstrated that children with internalising and externalising symptoms show distinct cognitive profiles. Children with more externalising symptoms performed lower in the attention/executive functioning domain, while children with more internalising symptoms showed impairment in verbal fluency and memory. In the most severely affected class of children with internalising and externalising symptoms, we found specific impairment in the sensorimotor domain. This study illustrates the specific interrelation of internalising and externalising symptoms and cognition in young children.

  17. Firearm and Nonfirearm Homicide in 5 South African Cities: A Retrospective Population-Based Study

    PubMed Central

    Thompson, Mary Lou; Myers, Jonathan E.

    2014-01-01

    Objective. We assessed the effectiveness of South Africa’s Firearm Control Act (FCA), passed in 2000, on firearm homicide rates compared with rates of nonfirearm homicide across 5 South African cities from 2001 to 2005. Methods. We conducted a retrospective population-based study of 37 067 firearm and nonfirearm homicide cases. Generalized linear models helped estimate and compare time trends of firearm and nonfirearm homicides, adjusting for age, sex, race, day of week, city, year of death, and population size. Results. There was a statistically significant decreasing trend regarding firearm homicides from 2001, with an adjusted year-on-year homicide rate ratio of 0.864 (95% confidence interval [CI] = 0.848, 0.880), representing a decrease of 13.6% per annum. The year-on-year decrease in nonfirearm homicide rates was also significant, but considerably lower at 0.976 (95% CI = 0.954, 0.997). Results suggest that 4585 (95% CI = 4427, 4723) lives were saved across 5 cities from 2001 to 2005 because of the FCA. Conclusions. Strength, timing and consistent decline suggest stricter gun control mediated by the FCA accounted for a significant decrease in homicide overall, and firearm homicide in particular, during the study period. PMID:24432917

  18. Multiple myeloma and infections: a population-based study on 9253 multiple myeloma patients.

    PubMed

    Blimark, Cecilie; Holmberg, Erik; Mellqvist, Ulf-Henrik; Landgren, Ola; Björkholm, Magnus; Hultcrantz, Malin; Kjellander, Christian; Turesson, Ingemar; Kristinsson, Sigurdur Y

    2015-01-01

    Infections are a major cause of morbidity and mortality in patients with multiple myeloma. To estimate the risk of bacterial and viral infections in multiple myeloma patients, we used population-based data from Sweden to identify all multiple myeloma patients (n=9253) diagnosed from 1988 to 2004 with follow up to 2007 and 34,931 matched controls. Cox proportional hazard models were used to estimate the risk of infections. Overall, multiple myeloma patients had a 7-fold (hazard ratio =7.1; 95% confidence interval = 6.8-7.4) risk of developing any infection compared to matched controls. The increased risk of developing a bacterial infection was 7-fold (7.1; 6.8-7.4), and for viral infections 10-fold (10.0; 8.9-11.4). Multiple myeloma patients diagnosed in the more recent calendar periods had significantly higher risk of infections compared to controls (P<0.001). At one year of follow up, infection was the underlying cause in 22% of deaths in multiple myeloma patients. Mortality due to infections remained constant during the study period. Our findings confirm that infections represent a major threat to multiple myeloma patients. The effect on infectious complications due to novel drugs introduced in the treatment of multiple myeloma needs to be established and trials on prophylactic measures are needed.

  19. Associating optical measurements of MEO and GEO objects using Population-Based Meta-Heuristic methods

    NASA Astrophysics Data System (ADS)

    Zittersteijn, M.; Vananti, A.; Schildknecht, T.; Dolado Perez, J. C.; Martinot, V.

    2016-11-01

    Currently several thousands of objects are being tracked in the MEO and GEO regions through optical means. The problem faced in this framework is that of Multiple Target Tracking (MTT). The MTT problem quickly becomes an NP-hard combinatorial optimization problem. This means that the effort required to solve the MTT problem increases exponentially with the number of tracked objects. In an attempt to find an approximate solution of sufficient quality, several Population-Based Meta-Heuristic (PBMH) algorithms are implemented and tested on simulated optical measurements. These first results show that one of the tested algorithms, namely the Elitist Genetic Algorithm (EGA), consistently displays the desired behavior of finding good approximate solutions before reaching the optimum. The results further suggest that the algorithm possesses a polynomial time complexity, as the computation times are consistent with a polynomial model. With the advent of improved sensors and a heightened interest in the problem of space debris, it is expected that the number of tracked objects will grow by an order of magnitude in the near future. This research aims to provide a method that can treat the association and orbit determination problems simultaneously, and is able to efficiently process large data sets with minimal manual intervention.

  20. Metformin use and survival from lung cancer: A population-based cohort study.

    PubMed

    Menamin, Úna C Mc; Cardwell, Chris R; Hughes, Carmel M; Murray, Liam M

    2016-04-01

    Preclinical evidence suggests that metformin, a widely prescribed anti-diabetic drug, may inhibit lung cancer progression. We investigated whether metformin use was associated with decreased risk of cancer-specific mortality in lung cancer patients. This study included newly diagnosed lung cancer patients (identified from English National Cancer Data Repository, 1998-2009) with type 2 diabetes (based on UK Clinical Practice Research Datalink prescriptions and diagnosis records). Lung cancer deaths occurring up to 2012 were identified using Office of National Statistics mortality data and the association between metformin use (before and after diagnosis) and risk of lung cancer-specific mortality was calculated using Cox regression models. In analysis of 533 patients, we found a weak non-significant reduction in lung cancer-specific mortality with metformin use after diagnosis (adjusted HR, 0.86; 95% CI, 0.68-1.09). No association was evident for metformin use before diagnosis and cancer-specific mortality in analysis of 1350 patients (adjusted HR, 0.97; 95% CI, 0.86, 1.11). Associations were similar by duration of use. In addition, after adjustment for potential confounders, there was little evidence of an association between the use of other anti-diabetic medications (either before or after diagnosis) and lung cancer-specific mortality; including sulfonylureas, insulin or other anti-diabetic medications (such as thiazolidinediones). Overall, the results from this population-based study provide little evidence of a protective association between metformin use and cancer mortality in lung cancer patients.

  1. Population-based survival-cure analysis of ER-negative breast cancer.

    PubMed

    Huang, Lan; Johnson, Karen A; Mariotto, Angela B; Dignam, James J; Feuer, Eric J

    2010-08-01

    This study investigated the trends over time in age and stage specific population-based survival of estrogen receptor negative (ER-) breast cancer patients by examining the fraction of cured patients and the median survival time for uncured patients. Cause-specific survival data from the Surveillance, Epidemiology, and End Results program for cases diagnosed during 1992-1998 were used in mixed survival cure models to evaluate the cure fraction and the extension in survival for uncured patients. Survival trends were compared with adjuvant chemotherapy data available from an overlapping patterns-of-care study. For stage II N+ disease, the largest increase in cure fraction was 44-60% (P = 0.0257) for women aged >or=70 in contrast to a 7-8% point increase for women aged <50 or 50-69 (P = 0.056 and 0.038, respectively). For women with stage III disease, the increases in the cure fraction were not statistically significant, although women aged 50-69 had a 10% point increase (P = 0.103). Increases in cure fraction correspond with increases in the use of adjuvant chemotherapy, particularly for the oldest age group. In this article, for the first time, we estimate the cure fraction for ER- patients. We notice that at age >o5r=70, the accelerated increase in cure fraction from 1992 to 1998 for women with stage II N+ compared with stage III suggests a selective benefit for chemotherapy in the lower stage group.

  2. Inverse Association of Parkinson Disease With Systemic Lupus Erythematosus: A Nationwide Population-based Study.

    PubMed

    Liu, Feng-Cheng; Huang, Wen-Yen; Lin, Te-Yu; Shen, Chih-Hao; Chou, Yu-Ching; Lin, Cheng-Li; Lin, Kuen-Tze; Kao, Chia-Hung

    2015-11-01

    The effects of the inflammatory mediators involved in systemic lupus erythematous (SLE) on subsequent Parkinson disease have been reported, but no relevant studies have focused on the association between the 2 diseases. This nationwide population-based study evaluated the risk of Parkinson disease in patients with SLE.We identified 12,817 patients in the Taiwan National Health Insurance database diagnosed with SLE between 2000 and 2010 and compared the incidence rate of Parkinson disease among these patients with that among 51,268 randomly selected age and sex-matched non-SLE patients. A Cox multivariable proportional-hazards model was used to evaluate the risk factors of Parkinson disease in the SLE cohort.We observed an inverse association between a diagnosis of SLE and the risk of subsequent Parkinson disease, with the crude hazard ratio (HR) being 0.60 (95% confidence interval 0.45-0.79) and adjusted HR being 0.68 (95% confidence interval 0.51-0.90). The cumulative incidence of Parkinson disease was 0.83% lower in the SLE cohort than in the non-SLE cohort. The adjusted HR of Parkinson disease decreased as the follow-up duration increased and was decreased among older lupus patients with comorbidity.We determined that patients with SLE had a decreased risk of subsequent Parkinson disease. Further research is required to elucidate the underlying mechanism.

  3. Noise Annoyance in Urban Children: A Cross-Sectional Population-Based Study

    PubMed Central

    Grelat, Natacha; Houot, Hélène; Pujol, Sophie; Levain, Jean-Pierre; Defrance, Jérôme; Mariet, Anne-Sophie; Mauny, Frédéric

    2016-01-01

    Acoustical and non-acoustical factors influencing noise annoyance in adults have been well-documented in recent years; however, similar knowledge is lacking in children. The aim of this study was to quantify the annoyance caused by chronic ambient noise at home in children and to assess the relationship between these children′s noise annoyance level and individual and contextual factors in the surrounding urban area. A cross sectional population-based study was conducted including 517 children attending primary school in a European city. Noise annoyance was measured using a self-report questionnaire adapted for children. Six noise exposure level indicators were built at different locations at increasing distances from the child′s bedroom window using a validated strategic noise map. Multilevel logistic models were constructed to investigate factors associated with noise annoyance in children. Noise indicators in front of the child′s bedroom (p ≤ 0.01), family residential satisfaction (p ≤ 0.03) and socioeconomic characteristics of the individuals and their neighbourhood (p ≤ 0.05) remained associated with child annoyance. These findings illustrate the complex relationships between our environment, how we may perceive it, social factors and health. Better understanding of these relationships will undoubtedly allow us to more effectively quantify the actual effect of noise on human health. PMID:27801858

  4. Incidence of hidradenitis suppurativa and associated factors: a population-based study of Olmsted County, Minnesota.

    PubMed

    Vazquez, Benjamin G; Alikhan, Ali; Weaver, Amy L; Wetter, David A; Davis, Mark D

    2013-01-01

    There are no population-based incidence studies of hidradenitis suppurativa (HS). Using the medical record linkage system of the Rochester Epidemiology Project, we sought to determine the incidence of the disease, as well as other associations and characteristics, among HS patients diagnosed in Olmsted County, Minnesota, between 1968 and 2008. Incidence was estimated using the decennial census data for the county. Logistic regression models were fit to evaluate associations between patient characteristics and disease severity. A total of 268 incident cases were identified, with an overall annual age- and sex-adjusted incidence of 6.0 per 100,000. Age-adjusted incidence was significantly higher in women compared with men (8.2 (95% confidence interval (CI), 7.0-9.3) vs. 3.8 (95% CI, 3.0-4.7). The highest incidence was among young women aged 20-29 years (18.4 per 100,000). The incidence has risen over the past four decades, particularly among women. Women were more likely to have axillary and upper anterior torso involvement, whereas men were more likely to have perineal or perianal disease. In addition, 54.9% (140/255) patients were obese; 70.2% were current or former smokers; 42.9% carried a diagnosis of depression; 36.2% carried a diagnosis of acne; and 6% had pilonidal disease. Smoking and gender were significantly associated with more severe disease.

  5. Insomnia and the Risk of Atrial Fibrillation: A Population-Based Cohort Study

    PubMed Central

    Lee, Hsiu-Hao; Chen, Yueh-Chung; Chen, Jien-Jiun; Lo, Shih-Hsiang; Guo, Yue-Liang; Hu, Hsiao-Yun

    2017-01-01

    Background Although advancements in the treatment of atrial fibrillation have improved patient prognosis for this persistent condition, interest in atrial fibrillation development is growing. Of note is the fact that additional attention is being focused on the accompanying effect of insomnia. The aim of the study was to investigate the effects of insomnia on the risk of atrial fibrillation development. Methods This was a nationwide population-based retrospective cohort study using data from the Taiwan National health Insurance Research Database. We analyzed 64,421 insomnia cases and 128,842 matched controls without insomnia from January 1, 2000, to December 31, 2010. A Cox regression model was used to estimate the adjusted hazard ratios (HRs) and 95% confidence intervals (CI) for atrial fibrillation development. Results During the follow-up period, the incidence of atrial fibrillation development was significantly higher in the insomnia cases than in the comparison cohort (2.6% vs. 2.3%, p < 0.001). Insomnia was associated with an increased risk of atrial fibrillation (HR = 1.08, 95% CI: 1.01-1.14). Males, those > 65 years of age, and patients with peripheral artery disease who have insomnia had a higher rate of atrial fibrillation development. Conclusions The findings of this nationwide analysis support the hypothesis that insomnia is associated with a significant risk of atrial fibrillation development. PMID:28344420

  6. Sleep and academic performance in later adolescence: results from a large population-based study.

    PubMed

    Hysing, Mari; Harvey, Allison G; Linton, Steven J; Askeland, Kristin G; Sivertsen, Børge

    2016-06-01

    The aim of the current study was to assess the association between sleep duration and sleep patterns and academic performance in 16-19 year-old adolescents using registry-based academic grades. A large population-based study from Norway conducted in 2012, the youth@hordaland-survey, surveyed 7798 adolescents aged 16-19 years (53.5% girls). The survey was linked with objective outcome data on school performance. Self-reported sleep measures provided information on sleep duration, sleep efficiency, sleep deficit and bedtime differences between weekday and weekend. School performance [grade point average (GPA)] was obtained from official administrative registries. Most sleep parameters were associated with increased risk for poor school performance. After adjusting for sociodemographic information, short sleep duration and sleep deficit were the sleep measures with the highest odds of poor GPA (lowest quartile). Weekday bedtime was associated significantly with GPA, with adolescents going to bed between 22:00 and 23:00 hours having the best GPA. Also, delayed sleep schedule during weekends was associated with poor academic performance. The associations were somewhat reduced after additional adjustment for non-attendance at school, but remained significant in the fully adjusted models. In conclusion, the demonstrated relationship between sleep problems and poor academic performance suggests that careful assessment of sleep is warranted when adolescents are underperforming at school. Future studies are needed on the association between impaired sleep in adolescence and later functioning in adulthood.

  7. Population-based 3D genome structure analysis reveals driving forces in spatial genome organization

    PubMed Central

    Li, Wenyuan; Kalhor, Reza; Dai, Chao; Hao, Shengli; Gong, Ke; Zhou, Yonggang; Li, Haochen; Zhou, Xianghong Jasmine; Le Gros, Mark A.; Larabell, Carolyn A.; Chen, Lin; Alber, Frank

    2016-01-01

    Conformation capture technologies (e.g., Hi-C) chart physical interactions between chromatin regions on a genome-wide scale. However, the structural variability of the genome between cells poses a great challenge to interpreting ensemble-averaged Hi-C data, particularly for long-range and interchromosomal interactions. Here, we present a probabilistic approach for deconvoluting Hi-C data into a model population of distinct diploid 3D genome structures, which facilitates the detection of chromatin interactions likely to co-occur in individual cells. Our approach incorporates the stochastic nature of chromosome conformations and allows a detailed analysis of alternative chromatin structure states. For example, we predict and experimentally confirm the presence of large centromere clusters with distinct chromosome compositions varying between individual cells. The stability of these clusters varies greatly with their chromosome identities. We show that these chromosome-specific clusters can play a key role in the overall chromosome positioning in the nucleus and stabilizing specific chromatin interactions. By explicitly considering genome structural variability, our population-based method provides an important tool for revealing novel insights into the key factors shaping the spatial genome organization. PMID:26951677

  8. Efficiency and lifetime of carbon foils

    SciTech Connect

    Chou, W.; Kostin, M.; Tang, Z.; /Fermilab

    2006-11-01

    Charge-exchange injection by means of carbon foils is a widely used method in accelerators. This paper discusses two critical issues concerning the use of carbon foils: efficiency and lifetime. An energy scaling of stripping efficiency was suggested and compared with measurements. Several factors that determine the foil lifetime--energy deposition, heating, stress and buckling--were studied by using the simulation codes MARS and ANSYS.

  9. High Precision Measurement of the ^19Ne Lifetime

    NASA Astrophysics Data System (ADS)

    Broussard, Leah; Back, H. O.; Boswell, M. S.; Crowell, A. S.; Howell, C. R.; Kidd, M. F.; Pattie, R. W., Jr.; Young, A. R.; Dendooven, P. G.; Giri, G. S.; van der Hoek, D. J.; Jungmann, K.; Kruithof, W. L.; Onderwater, C. J. G.; Santra, B.; Shidling, P. D.; Sohani, M.; Versolota, O. O.; Willmann, L.; Wilschut, H. W.

    2009-10-01

    Recently, a rigorous review of the T=12 mirror transitions has identified several systems which can contribute to high precision tests exploring deviations from the Standard Model's description of the electroweak interaction. Arguably, one of the best candidates is the &+circ; decay of ^19Ne to ^19F. In this system, the main contribution to the uncertainty of extracted Standard Model parameters is due to the measured value of the lifetime of the decay. In March 2009, a high precision measurement of the lifetime of ^19Ne was made by a collaboration between the Triangle Universities Nuclear Laboratory (TUNL) and the Kernfysisch Versneller Instituut (KVI) at the Trapped Radioactive Isotopes: Microlaboratories for Fundamental Physics (Triμp) facility. An overview of the experiment and preliminary results will be presented.

  10. Phonon-lifetimes in demixing systems

    NASA Astrophysics Data System (ADS)

    Davaasambuu, J.; Güthoff, F.; Petri, M.; Hradil, K.; Schober, H.; Ollivier, J.; Eckold, G.

    2012-06-01

    The dynamics of silver-alkali halide mixed single crystals (AgxNa1-xBr, x = 0.23, 0.35, 0.40 and 0.70) were studied by inelastic neutron scattering during the process of spinodal decomposition. Using the thermal three-axes spectrometer PUMA as well as the time-of-flight spectrometer IN5, the time evolution of phonons was observed in time-resolved, stroboscopic measurements. Complementary to the study of long wavelength acoustic phonons, as studied previously, we extended these investigations to Brillouin-zone boundary modes that are particularly sensitive to variations of the local structure. Starting from the homogeneous mixed phase the behaviour of these modes during demixing is observed in real-time. A simple dynamical model based on local structure variants helps to interpret the results. It is shown that the phonon lifetimes vary strongly during the phase separation and increase drastically during the coarsening process. Up to a critical size of precipitates of about 10 nm, zone-boundary modes are found to be strongly damped, while beyond the line widths are reduced to the experimental resolution. This finding leads to the conclusion that the typical mean free path of these modes is of the order of 10 nm, which corresponds to 20 unit cells.

  11. A Measurement of the Bs Lifetime at CDF Run II

    SciTech Connect

    Farrington, Sinead

    2004-01-01

    This thesis describes a measurement of the proper lifetime of the B$0\\atop{s}$ mesons produced in proton-antiproton collisions at a center of mass energy of 1.96 TeV, collected by the CDF experiment at Fermilab. The B$0\\atop{s}$ meson lifetime is measured in its semileptonic decay mode, B$0\\atop{s}$ → ℓ+vD$-\\atop{s}$. The D$-\\atop{s}$ meson candidates are reconstructed in the decay mode D$-\\atop{s}$ → Φπ, with Φ → K+K-, in a trigger sample which requires a muon or an electron and another track which has a large impact parameters. The large impact parameter track is required by the silicon vertex trigger which is an innovative triggering device which has not previously been used in lifetime measurements. A total of 905 ± B$0\\atop{s}$ candidates are reconstructed in a sample which has an integrated luminosity of 140 pb-1 using data gathered between February 2002 and August 2003. The pseudo-proper lifetime distribution of these candidates is fitted with an unbinned maximum likelihood fit. This fit takes into account the missing momentum carried by the neutrino and the bias caused by requiring a track with large impact parameter by modeling these effects in simulations. The fit yields the result for the B$0\\atop{s}$ proper lifetime: cτ(B$0\\atop{s}$) = 419 ± 28$+16\\atop{-13}$ μm and τ(B$0\\atop{s}$) = 1.397 ± 0.093$+0.053\\atop{-0.043}$ ps where the first error is statistical and the second is systematic.

  12. Total variation versus wavelet-based methods for image denoising in fluorescence lifetime imaging microscopy.

    PubMed

    Chang, Ching-Wei; Mycek, Mary-Ann

    2012-05-01

    We report the first application of wavelet-based denoising (noise removal) methods to time-domain box-car fluorescence lifetime imaging microscopy (FLIM) images and compare the results to novel total variation (TV) denoising methods. Methods were tested first on artificial images and then applied to low-light live-cell images. Relative to undenoised images, TV methods could improve lifetime precision up to 10-fold in artificial images, while preserving the overall accuracy of lifetime and amplitude values of a single-exponential decay model and improving local lifetime fitting in live-cell images. Wavelet-based methods were at least 4-fold faster than TV methods, but could introduce significant inaccuracies in recovered lifetime values. The denoising methods discussed can potentially enhance a variety of FLIM applications, including live-cell, in vivo animal, or endoscopic imaging studies, especially under challenging imaging conditions such as low-light or fast video-rate imaging.

  13. Effects of surface orientation on lifetime of near-surface nanoscale He bubble in tungsten

    NASA Astrophysics Data System (ADS)

    Cui, Jiechao; Fu, Baoqin; Wu, Zhangwen; Hou, Qing

    2017-02-01

    In multiscale modeling of the morphological evolution of plasma facing materials in nuclear fusion reactors, the knowledge of the timescales of the involved physical processes is important. In the present study, a new method based on molecular dynamics simulations was developed to extract the lifetime of helium bubbles near tungsten surfaces. It was found that the lifetime of a helium bubble can be described by the Arrhenius equation. However, the lifetime of a helium bubble depends on the thickness of tungsten film above the helium bubble in the substrate and the bubble size. The influence of surface orientations on the lifetime of helium bubbles was also observed, and the performance of helium bubbles on the (1 1 1) surface is very different from on the (0 0 1) and (0 1 1) surfaces. The role of the helium bubble lifetime in other simulation techniques, such as in kinetic Monte Carlo methods and rate theory, is discussed.

  14. Fatigue-creep lifetime analysis of four advanced central receiver concepts

    NASA Astrophysics Data System (ADS)

    Jones, J.

    1981-01-01

    Four advanced central receiver concepts were analyzed for their fatigue-creep design lifetimes. Using the flux profiles provided by the designers, the thermal hydraulic performance of an individual tube in a receiver panel was ascertained by computer analysis. A linear model of the tube crown strain for the tube on given thermal and structural finite element analyses were performed. The computed stresses and strains were used in evaluation of the creep and fatigue design lifetimes by N-47 and compared to the desired lifetime of 30 years. Three of the four designs met or exceeded the desired lifetime and the fourth met the desired lifetime when the factor of safety incorporated in N-47 was reduced. All four designs were judged adequate for the current level of design effort.

  15. Long-term air pollution exposure and diabetes in a population-based Swiss cohort.

    PubMed

    Eze, Ikenna C; Schaffner, Emmanuel; Fischer, Evelyn; Schikowski, Tamara; Adam, Martin; Imboden, Medea; Tsai, Ming; Carballo, David; von Eckardstein, Arnold; Künzli, Nino; Schindler, Christian; Probst-Hensch, Nicole

    2014-09-01

    Air pollution is an important risk factor for global burden of disease. There has been recent interest in its possible role in the etiology of diabetes mellitus. Experimental evidence is suggestive, but epidemiological evidence is limited and mixed. We therefore explored the association between air pollution and prevalent diabetes, in a population-based Swiss cohort. We did cross-sectional analyses of 6392 participants of the Swiss Cohort Study on Air Pollution and Lung and Heart Diseases in Adults [SAPALDIA], aged between 29 and 73 years. We used estimates of average individual home outdoor PM10 [particulate matter <10μm in diameter] and NO2 [nitrogen dioxide] exposure over the 10 years preceding the survey. Their association with diabetes was modeled using mixed logistic regression models, including participants' study area as random effect, with incremental adjustment for confounders. There were 315 cases of diabetes (prevalence: 5.5% [95% confidence interval (CI): 2.8, 7.2%]). Both PM10 and NO2 were associated with prevalent diabetes with respective odds ratios of 1.40 [95% CI: 1.17, 1.67] and 1.19 [95% CI: 1.03, 1.38] per 10μg/m(3) increase in the average home outdoor level. Associations with PM10 were generally stronger than with NO2, even in the two-pollutant model. There was some indication that beta blockers mitigated the effect of PM10. The associations remained stable across different sensitivity analyses. Our study adds to the evidence that long term air pollution exposure is associated with diabetes mellitus. PM10 appears to be a useful marker of aspects of air pollution relevant for diabetes. This association can be observed at concentrations below air quality guidelines.

  16. A Population-Based Genomic Study of Inherited Metabolic Diseases Detected Through Newborn Screening

    PubMed Central

    Park, Kyoung-Jin; Park, Seungman; Lee, Eunhee; Park, Jong-Ho; Park, June-Hee; Park, Hyung-Doo; Lee, Soo-Youn

    2016-01-01

    Background A newborn screening (NBS) program has been utilized to detect asymptomatic newborns with inherited metabolic diseases (IMDs). There have been some bottlenecks such as false-positives and imprecision in the current NBS tests. To overcome these issues, we developed a multigene panel for IMD testing and investigated the utility of our integrated screening model in a routine NBS environment. We also evaluated the genetic epidemiologic characteristics of IMDs in a Korean population. Methods In total, 269 dried blood spots with positive results from current NBS tests were collected from 120,700 consecutive newborns. We screened 97 genes related to NBS in Korea and detected IMDs, using an integrated screening model based on biochemical tests and next-generation sequencing (NGS) called NewbornSeq. Haplotype analysis was conducted to detect founder effects. Results The overall positive rate of IMDs was 20%. We identified 10 additional newborns with preventable IMDs that would not have been detected prior to the implementation of our NGS-based platform NewbornSeq. The incidence of IMDs was approximately 1 in 2,235 births. Haplotype analysis demonstrated founder effects in p.Y138X in DUOXA2, p.R885Q in DUOX2, p.Y439C in PCCB, p.R285Pfs*2 in SLC25A13, and p.R224Q in GALT. Conclusions Through a population-based study in the NBS environment, we highlight the screening and epidemiological implications of NGS. The integrated screening model will effectively contribute to public health by enabling faster and more accurate IMD detection through NBS. This study suggested founder mutations as an explanation for recurrent IMD-causing mutations in the Korean population. PMID:27578510

  17. Lifetimes and Structure of Excited States of 73AS

    NASA Astrophysics Data System (ADS)

    Bucurescu, D.; Căta-Danil, I.; Ivaşcu, M.; Mărginean, N.; Stroe, L.; Ur, C. A.; Dinu, N.

    The lifetimes of twelve low spin excited states in 73As, below 2 MeV excitation, have been measured with the DSA method in the 73Ge(p,nγ) reaction. The existing data (energy levels, electromagnetic moments, transition probabilities and branching ratios, one-nucleon transfer spectroscopic factors) are discussed in the frame of multi-shell interacting boson-fermion model calculations. A good agreement is obtained for a large number of levels.

  18. T Tauri Disk Lifetime in the Lupus Association

    NASA Astrophysics Data System (ADS)

    Galli, P. A. B.; Bertout, C.; Teixeira, R.; Ducourant, C.

    2016-01-01

    In a recent study, we derived individual distances for a sample of pre-main sequence stars that define the comoving association of young stars in the Lupus star-forming region. Here, we use these new distances to investigate the mass and age distributions of Lupus T Tauri stars and derive the average disk lifetime in the Lupus association based on an empirical disk model.

  19. Lifetime-based sensing:  influence of the microenvironment.

    PubMed

    Draxler, S; Lippitsch, M E

    1996-03-01

    The influence of the microenvironment on the fluorescence behavior of indicator molecules is investigated. A model is developed to describe the fluorescence decay of indicator molecules in a nonuniform medium. Its consequences for fluorescence lifetime-based chemical sensors are discussed and verified in two examples, namely, a pH sensor using a pyrene compound in a hydrogel and a ruthenium complex for oxygen sensing embedded in a polystyrene membrane.

  20. Prevalence of Hidradenitis Suppurativa (HS): A Population-Based Study in Olmsted County, Minnesota

    PubMed Central

    Shahi, Varun; Alikhan, Ali; Vazquez, Benjamin G.; Weaver, Amy L.; Davis, Mark D.

    2014-01-01

    BACKGROUND/AIMS Hidradenitis suppurativa (HS) is a follicular occlusion disorder occurring in apocrine-rich regions of the skin. Estimates of the prevalence of this disorder have not been population-based. We sought to provide population-based information on the prevalence of HS in Olmsted County, Minnesota as of 1/1/2009. METHODS Rochester Epidemiology Project, a unique infrastructure that combines and makes accessible all medical records in Olmsted County since the 1960s, was used to collect population-based data on the prevalence of HS. RESULTS We identified 178 confirmed cases of HS that included 135 females and 43 males, and estimated the total sex- and age-adjusted prevalence in Olmsted County to be 127.8 per 100,000 or 0.13%. The total prevalence was significantly higher among women than men. CONCLUSION This study represents the first population-based investigation on the prevalence of HS. In this population-based cohort, HS was less prevalent than previous reports have suggested. PMID:25228133

  1. Fluorescence lifetime excitation cytometry by kinetic dithering.

    PubMed

    Li, Wenyan; Vacca, Giacomo; Castillo, Maryann; Houston, Kevin D; Houston, Jessica P

    2014-07-01

    Flow cytometers are powerful high-throughput devices that capture spectroscopic information from individual particles or cells. These instruments provide a means of multi-parametric analyses for various cellular biomarkers or labeled organelles and cellular proteins. However, the spectral overlap of fluorophores limits the number of fluorophores that can be used simultaneously during experimentation. Time-resolved parameters enable the quantification of fluorescence decay kinetics, thus circumventing common issues associated with intensity-based measurements. This contribution introduces fluorescence lifetime excitation cytometry by kinetic dithering (FLECKD) as a method to capture multiple fluorescence lifetimes using a hybrid time-domain approach. The FLECKD approach excites fluorophores by delivering short pulses of light to cells or particles by rapid dithering and facilitates measurement of complex fluorescence decay kinetics by flow cytometry. Our simulations demonstrated a resolvable fluorescence lifetime value as low as 1.8 ns (±0.3 ns) with less than 20% absolute error. Using the FLECKD instrument, we measured the shortest average fluorescence lifetime value of 2.4 ns and found the system measurement error to be ±0.3 ns (SEM), from hundreds of monodisperse and chemically stable fluorescent microspheres. Additionally, we demonstrate the ability to detect two distinct excited state lifetimes from fluorophores in single cells using FLECKD. This approach presents a new ability to resolve multiple fluorescence lifetimes while retaining the fluidic throughput of a cytometry system. The ability to discriminate more than one average fluorescence lifetime expands the current capabilities of high-throughput and intensity-based cytometry assays as the need to tag one single cell with multiple fluorophores is now widespread.

  2. Use of BPPV processes in Emergency Department Dizziness Presentations: A Population-Based Study

    PubMed Central

    Kerber, Kevin A.; Burke, James F.; Skolarus, Lesli E.; Meurer, William J.; Callaghan, Brian C.; Brown, Devin L.; Lisabeth, Lynda D.; McLaughlin, Thomas J.; Fendrick, A. Mark; Morgenstern, Lewis B.

    2013-01-01

    Objective A common cause of dizziness, benign paroxysmal positional vertigo (BPPV), is effectively diagnosed and cured with the Dix-Hallpike test (DHT) and the canalith repositioning maneuver (CRM). We aimed to describe the use of these processes in Emergency Departments (ED), to assess for trends in use over time, and to determine provider level variability in use. Design Prospective population-based surveillance study Setting EDs in Nueces County, Texas, January 15, 2008 to January 14, 2011 Subjects and Methods Adult patients discharged from EDs with dizziness, vertigo, or imbalance documented at triage. Clinical information was abstracted from source documents. A hierarchical logistic regression model adjusting for patient and provider characteristics was used to estimate trends in DHT use and provider level variability. Results 3,522 visits for dizziness were identified. A DHT was documented in 137 visits (3.9%). A CRM was documented in 8 visits (0.2%). Among patients diagnosed with BPPV, a DHT was documented in only 21.8% (34 of 156) and a CRM in 3.9% (6 of 156). In the hierarchical model (c statistic = 0.93), DHT was less likely to be used over time (odds ratio, 0.97, 95% CI [0.95, 0.99]) and the provider level explained 50% (ICC, 0.50) of the variance in the probability of DHT use. Conclusion BPPV is seldom examined for, and when diagnosed, infrequently treated in this ED population. DHT use is decreasing over time, and varies substantially by provider. Implementation research focused on BPPV care may be an opportunity to optimize management in ED dizziness presentations. PMID:23264119

  3. Radiotherapy and Survival in Prostate Cancer Patients: A Population-Based Study

    SciTech Connect

    Zhou, Esther H. Ellis, Rodney J.; Cherullo, Edward; Colussi, Valdir; Xu Fang; Chen Weidong; Gupta, Sanjay; Whalen, Christopher C.; Bodner, Donald; Resnick, Martin I.; Rimm, Alfred A.

    2009-01-01

    Purpose: To investigate the association of overall and disease-specific survival with the five standard treatment modalities for prostate cancer (CaP): radical prostatectomy (RP), brachytherapy (BT), external beam radiotherapy, androgen deprivation therapy, and no treatment (NT) within 6 months after CaP diagnosis. Methods and Materials: The study population included 10,179 men aged 65 years and older with incident CaP diagnosed between 1999 and 2001. Using the linked Ohio Cancer Incidence Surveillance System, Medicare, and death certificate files, overall and disease-specific survival through 2005 among the five clinically accepted therapies were analyzed. Results: Disease-specific survival rates were 92.3% and 23.9% for patients with localized vs. distant disease at 7 years, respectively. Controlling for age, race, comorbidities, stage, and Gleason score, results from the Cox multiple regression models indicated that the risk of CaP-specific death was significantly reduced in patients receiving RP or BT, compared with NT. For localized disease, compared with NT, in the monotherapy cohort, RP and BT were associated with reduced hazard ratios (HR) of 0.25 and 0.45 (95% confidence intervals 0.13-0.48 and 0.23-0.87, respectively), whereas in the combination therapy cohort, HR were 0.40 (0.17-0.94) and 0.46 (0.27-0.80), respectively. Conclusions: The present population-based study indicates that RP and BT are associated with improved survival outcomes. Further studies are warranted to improve clinical determinates in the selection of appropriate management of CaP and to improve predictive modeling for which patient subsets may benefit most from definitive therapy vs. conservative management and/or observation.

  4. Direct costs in impaired glucose regulation: results from the population-based Heinz Nixdorf Recall study

    PubMed Central

    Bächle, C; Claessen, H; Andrich, S; Brüne, M; Dintsios, C M; Slomiany, U; Roggenbuck, U; Jöckel, K H; Moebus, S; Icks, A

    2016-01-01

    Objective For the first time, this population-based study sought to analyze healthcare utilization and associated costs in people with normal fasting glycemia (NFG), impaired fasting glycemia (IFG), as well as previously undetected diabetes and previously diagnosed diabetes linking data from the prospective German Heinz Nixdorf Recall (HNR) study with individual claims data from German statutory health insurances. Research design and methods A total of 1709 participants of the HNR 5-year follow-up (mean age (SD) 64.9 (7.5) years, 44.5% men) were included in the study. Age-standardized and sex-standardized healthcare utilization and associated costs (reported as € for the year 2008, perspective of the statutory health insurance) were stratified by diabetes stage defined by the participants' self-report and fasting plasma glucose values. Cost ratios (CRs) were estimated using two-part regression models, adjusting for age, sex, sociodemographic variables and comorbidity. Results The mean total direct healthcare costs for previously diagnosed diabetes, previously undetected diabetes, IFG, and NFG were €2761 (95% CI 2378 to 3268), €2210 (1483 to 4279), €2035 (1732 to 2486) and €1810 (1634 to 2035), respectively. Corresponding age-adjusted and sex-adjusted CRs were 1.53 (1.30 to 1.80), 1.16 (0.91 to 1.47), and 1.09 (0.95 to 1.25) (reference: NFG). Inpatient, outpatient and medication costs varied in order between people with IFG and those with previously undetected diabetes. Conclusions The study provides claims-based detailed cost data in well-defined glucose metabolism subgroups. CRs of individuals with IFG and previously undetected diabetes were surprisingly low. Data are important for the model-based evaluation of screening programs and interventions that are aimed either to prevent diabetes onset or to improve diabetes therapy as well. PMID:27252871

  5. Usefulness of data from magnetic resonance imaging to improve prediction of dementia: population based cohort study

    PubMed Central

    Stephan, Blossom C M; Tzourio, Christophe; Auriacombe, Sophie; Amieva, Hélène; Dufouil, Carole; Alpérovitch, Annick

    2015-01-01

    Objective To determine whether the addition of data derived from magnetic resonance imaging (MRI) of the brain to a model incorporating conventional risk variables improves prediction of dementia over 10 years of follow-up. Design Population based cohort study of individuals aged ≥65. Setting The Dijon magnetic resonance imaging study cohort from the Three-City Study, France. Participants 1721 people without dementia who underwent an MRI scan at baseline and with known dementia status over 10 years’ follow-up. Main outcome measure Incident dementia (all cause and Alzheimer’s disease). Results During 10 years of follow-up, there were 119 confirmed cases of dementia, 84 of which were Alzheimer’s disease. The conventional risk model incorporated age, sex, education, cognition, physical function, lifestyle (smoking, alcohol use), health (cardiovascular disease, diabetes, systolic blood pressure), and the apolipoprotein genotype (C statistic for discrimination performance was 0.77, 95% confidence interval 0.71 to 0.82). No significant differences were observed in the discrimination performance of the conventional risk model compared with models incorporating data from MRI including white matter lesion volume (C statistic 0.77, 95% confidence interval 0.72 to 0.82; P=0.48 for difference of C statistics), brain volume (0.77, 0.72 to 0.82; P=0.60), hippocampal volume (0.79, 0.74 to 0.84; P=0.07), or all three variables combined (0.79, 0.75 to 0.84; P=0.05). Inclusion of hippocampal volume or all three MRI variables combined in the conventional model did, however, lead to significant improvement in reclassification measured by using the integrated discrimination improvement index (P=0.03 and P=0.04) and showed increased net benefit in decision curve analysis. Similar results were observed when the outcome was restricted to Alzheimer’s disease. Conclusions Data from MRI do not significantly improve discrimination performance in prediction of all cause dementia

  6. Stream Lifetimes Against Planetary Encounters

    NASA Technical Reports Server (NTRS)

    Valsecchi, G. B.; Lega, E.; Froeschle, Cl.

    2011-01-01

    We study, both analytically and numerically, the perturbation induced by an encounter with a planet on a meteoroid stream. Our analytical tool is the extension of pik s theory of close encounters, that we apply to streams described by geocentric variables. The resulting formulae are used to compute the rate at which a stream is dispersed by planetary encounters into the sporadic background. We have verified the accuracy of the analytical model using a numerical test.

  7. Open volume in bioadhesive detected by positron annihilation lifetime spectroscopy.

    PubMed

    Rätzke, Klaus; Wiegemann, Maja; Shaikh, Muhammad Qasim; Harms, Stephan; Adelung, Rainer; Egger, Werner; Sperr, Peter

    2010-07-01

    Barnacles attach to a wide variety of surfaces underwater and show substrate-specific adhesion mechanisms. Investigating and understanding these mechanisms is a key for developing new technical adhesives. We expected open volume (porosity) at the sub-nanometre scale to occur in barnacle adhesive. With positron annihilation lifetime spectroscopy (PALS) it is possible to detect porosity at the nanometre scale by determining the lifetime of positrons. This method has not been applied to bioadhesives so far. We showed that PALS is a suitable technique for the investigation of the barnacle base and its adhesive with respect to open volume. The results were interpreted using a standard model adapted from polymers. We thereby estimated pore sizes of 0.5 nm.

  8. Autoionizing states of He: Projectile-velocity-dependent lifetime

    NASA Astrophysics Data System (ADS)

    Otranto, S.; Garibotti, C. R.; Colavecchia, F. D.; Gasaneo, G.

    2001-02-01

    In this work, we study the dependence of the lifetime (τ) of an autoionizing state with the velocity (vP) of an ionic projectile of charge Z. We use a C2 model to represent the final state of the autoionized electron in the continuum of two centers. Explicit calculations for the helium autoionizing states 2s2(1S), 2p2(1D), and 2s2p(1P) are analyzed. We evaluate the decay law for the metastable initial state and find that τ increases as the projectile becomes faster and converges to the photoionization lifetime for high impact energies. A scaling law for τ is obtained in terms of the Sommerfeld parameter (Z/vP). Finally, we evaluate the transition probability for the autoionized electron and show that the mean half-width of the focusing peak decreases as vP increases.

  9. Lifetime reduction of a quantum emitter with quasiperiodic metamaterials

    NASA Astrophysics Data System (ADS)

    Moritake, Yuto; Nakayama, Kazuyuki; Suzuki, Toshihiro; Kurosawa, Hiroyuki; Kodama, Toshiyuki; Tomita, Satoshi; Yanagi, Hisao; Ishihara, Teruya

    2014-08-01

    Enhancement of light-matter interaction of a quantum emitter with subwavelength quasiperiodic metamaterials is proposed and demonstrated. The quasiperiodic metamaterials consist of subwavelength metal-dielectric multilayers, which are arranged into a Fibonacci lattice. The influence of Fibonacci metamaterials (FM) on the dipole emission is analyzed with a semiclassical model. The local density of states near FM is evaluated and a characteristic mode in higher wave numbers is revealed; a strong enhancement of the decay rate was predicted. A lifetime measurement is carried out and a reduction of lifetime of quantum dots on the surface of FM is observed. The enhancement of light-matter interaction arises from the localized latticelike state inherent for self-similar quasiperiodic order.

  10. Improved lifetime of microchannel-plate PMTs

    NASA Astrophysics Data System (ADS)

    Lehmann, A.; Britting, A.; Eyrich, W.; Uhlig, F.; Dzhygadlo, R.; Gerhardt, A.; Götzen, K.; Höhler, R.; Kalicy, G.; Kumawat, H.; Lehmann, D.; Lewandowski, B.; Patsyuk, M.; Peters, K.; Schepers, G.; Schmitt, L.; Schwarz, C.; Schwiening, J.; Traxler, M.; Zühlsdorf, M.; Dodokhov, V. Kh.; Düren, M.; Föhl, K.; Hayrapetyan, A.; Kröck, B.; Merle, O.; Rieke, J.; Cowie, E.; Keri, T.; Montgomery, R.; Rosner, G.; Achenbach, P.; Cardinali, M.; Hoek, M.; Lauth, W.; Sfienti, C.; Thiel, M.; Bühler, P.; Gruber, L.; Marton, J.; Suzuki, K.

    2014-12-01

    The charged particle identification at the PANDA experiment will be mainly performed with DIRC detectors. Because of their advantageous properties the preferred photon sensors are MCP-PMTs. However, until recently these devices showed serious aging problems which resulted in a diminishing quantum efficiency (QE) of the photo cathode. By applying innovative countermeasures against the aging causes, the manufacturers recently succeeded in drastically improving the lifetime of MCP-PMTs. Especially the application of an ALD coating technique to seal the material of the micro-channels proves very powerful and results in a lifetime of ≈ 6 C /cm2 integrated anode charge without a substantial QE degradation for the latest PHOTONIS XP85112. This paper will present a comparative measurement of the lifetime of several older and recent MCP-PMTs demonstrating this progress.

  11. Lifetimes of Rydberg states of Eu atoms

    NASA Astrophysics Data System (ADS)

    Jing, Hua; Ye, Shi-Wei; Dai, Chang-Jian

    2015-01-01

    The radiative lifetimes of the Eu 4f76snp (8PJ or 10PJ) Rydberg states with J = 5/2 and 11/2 are investigated with a combination of multi-step laser excitation and pulsed electric field ionization, from which their dependence on the effective principal quantum number is observed. The lifetimes of 21 states are reported along with an evaluation of their experimental uncertainty. The influence of blackbody radiation, due to the oven temperature, on the lifetime of the higher-n states is detected. The non-hydrogen behavior of the investigated states is also observed. Project supported by the National Natural Science Foundation of China (Grant No. 11174218).

  12. The lifetime and evolution of fibrils

    NASA Technical Reports Server (NTRS)

    Marsh, K. A.

    1976-01-01

    A detailed study was made of the lifetimes and evolution of fibrils in McMath 12417, using high resolution filtergrams in H alpha and CaII K made at Big Bear Solar Observatory. It was found that the lifetime of a fibril increases monotonically with its length. This relationship, together with the form of the variation of fibril lengths as a function of time, suggests that fibrils result from material being impulsively injected into magnetic field lines at approximately 30 km/sec, and returning under gravity. The lifetimes and apparent lengths of fibrils are then a function of the inclination of the field lines only. A study of wavelength scans through the H alpha line confirms that the apparent expansion and contraction of fibrils represents true mass motion.

  13. Tobacco-related cancers in India: A review of incidence reported from population-based cancer registries

    PubMed Central

    Asthana, Smita; Patil, Rakshit S.; Labani, Satyanarayana

    2016-01-01

    Background: Tobacco related cancers (TRC) account for major share of all cancers and updated of incidence data are helpful in policy changes. The aim was to present an update of TRCs on age-adjusted incidence data and corresponding lifetime risk of developing TRC for different regions of the country. Methods: The data for this study were obtained from published reports of 25 population-based cancer registries (PBCRs) in India. The PBCRs in different parts of India were divided into seven regions such as North, South, Central, Northeast, West, Rural West, and East. Data indicators such as age-adjusted rates (AARs) of incidence and the cumulative risks of TRCs up to the age of 64 years for each of the 10 TRC sites of either sex in each of 25 registries were obtained from the National Cancer Registry Programme reports. Results: Among all TRCs, esophagus, lung, hypopharynx, and mouth are the leading sites for both males and females. Males in Northeast region had the highest risk 1 in 27 of developing esophageal cancer, 1 in 67 for cancer of lungs and hypopharynx, followed by 1 in 143 for both mouth and tongue cancers. Females also had the highest risk of esophagus and lungs (1 in 63 female) and cancer of mouth (1 in 250) in Northeast region. Proportion of TRC in comparison of all cancer ranged from 11–25% for men and 3–18% for women. Conclusions: Proportion of TRC in relation to all cancers was still high in different registries of India including the Northeast region. PMID:27688608

  14. Prevalence of physical violence against children in Haiti: A national population-based cross-sectional survey.

    PubMed

    Flynn-O'Brien, Katherine T; Rivara, Frederick P; Weiss, Noel S; Lea, Veronica A; Marcelin, Louis H; Vertefeuille, John; Mercy, James A

    2016-01-01

    Although physical violence against children is common worldwide, there are no national estimates in Haiti. To establish baseline national estimates, a three-stage clustered sampling design was utilized to administer a population-based household survey about victimization due to physical violence to 13-24 year old Haitians (n=2,916), including those residing in camps or settlements. Descriptive statistics and weighted analysis techniques were used to estimate national lifetime prevalence and characteristics of physical violence against children. About two-thirds of respondents reported having experienced physical violence during childhood (67.0%; 95% CI 63.4-70.4), the percentage being similar in males and females. More than one-third of 13-17 year old respondents were victimized in the 12 months prior to survey administration (37.8%; 95% CI 33.6-42.1). The majority of violence was committed by parents and teachers; and the perceived intent was often punishment or discipline. While virtually all (98.8%; 95% CI 98.0-99.3) victims of childhood physical violence were punched, kicked, whipped or beaten; 11.0% (95% CI 9.2-13.2) were subject to abuse by a knife or other weapon. Injuries sustained from violence varied by victim gender and perpetrator, with twice as many females (9.6%; 95% CI 7.1-12.7) than males (4.0%; 95% CI 2.6-6.1) sustaining permanent injury or disfigurement by a family member or caregiver (p-value<.001). Our findings suggest that physical violence against children in Haiti is common, and may lead to severe injury. Characterization of the frequency and nature of this violence provides baseline estimates to inform interventions.

  15. The Mortality Penalty of Incarceration: Evidence from a Population-based Case-control Study of Working-age Males.

    PubMed

    Pridemore, William Alex

    2014-06-01

    There is a growing body of research on the effects of incarceration on health, though there are few studies in the sociological literature of the association between incarceration and premature mortality. This study examined the risk of male premature mortality associated with incarceration. Data came from the Izhevsk (Russia) Family Study, a large-scale population-based case-control design. Cases (n = 1,750) were male deaths aged 25 to 54 in Izhevsk between October 2003 and October 2005. Controls (n = 1,750) were selected at random from a city population register. The key independent variable was lifetime prevalence of incarceration. I used logistic regression to estimate mortality odds ratios, controlling for age, hazardous drinking, smoking status, marital status, and education. Seventeen percent of cases and 5 percent of controls had been incarcerated. Men who had been incarcerated were more than twice as likely as those who had not to experience premature mortality (odds ratio = 2.2, 95 percent confidence interval: 1.6-3.0). Relative to cases with no prior incarceration, cases who had been incarcerated were more likely to die from infectious diseases, respiratory diseases, non-alcohol-related accidental poisonings, and homicide. Taken together with other recent research, these results from a rigorous case-control design reveal not only that incarceration has durable effects on illness, but that its consequences extend to a greater risk of early death. I draw on the sociology of health literature on exposure, stress, and social integration to speculate about the reasons for this mortality penalty of incarceration.

  16. Vibrational lifetimes of protein amide modes

    SciTech Connect

    Peterson, K.A.; Rella, C.A.

    1995-12-31

    Measurement of the lifetimes of vibrational modes in proteins has been achieved with a single frequency infrared pump-probe technique using the Stanford Picosecond Free-electron Laser, These are the first direct measurements of vibrational dynamics in the polyamide structure of proteins. In this study, modes associated with the protein backbone are investigated. Results for the amide I band, which consists mainly of the stretching motion of the carbonyl unit of the amide linkage, show that relaxation from the first vibrational excited level (v=1) to the vibrational ground state (v=0) occurs within 1.5 picoseconds with apparent first order kinetics. Comparison of lifetimes for myoglobin and azurin, which have differing secondary structures, show a small but significant difference. The lifetime for the amide I band of myoglobin is 300 femtoseconds shorter than for azurin. Further measurements are in progress on other backbone vibrational modes and on the temperature dependence of the lifetimes. Comparison of vibrational dynamics for proteins with differing secondary structure and for different vibrational modes within a protein will lead to a greater understanding of energy transfer and dissipation in biological systems. In addition, these results have relevance to tissue ablation studies which have been conducted with pulsed infrared lasers. Vibrational lifetimes are necessary for calculating the rate at which the energy from absorbed infrared photons is converted to equilibrium thermal energy within the irradiated volume. The very fast vibrational lifetimes measured here indicate that mechanisms which involve direct vibrational up-pumping of the amide modes with consecutive laser pulses, leading to bond breakage or weakening, are not valid.

  17. Population-based analysis of Alzheimer’s disease risk alleles implicates genetic interactions

    PubMed Central

    Ebbert, Mark T. W.; Ridge, Perry G.; Wilson, Andrew R.; Sharp, Aaron R.; Bailey, Matthew; Norton, Maria C.; Tschanz, JoAnn T.; Munger, Ronald G.; Corcoran, Christopher D.; Kauwe, John S. K.

    2013-01-01

    Background Reported odds ratios and population attributable fractions (PAF) for late-onset Alzheimer’s disease (LOAD) risk loci (BIN1, ABCA7, CR1, MS4A4E, CD2AP, PICALM, MS4A6A, CD33, and CLU) come from clinically ascertained samples. Little is known about the combined PAF for these LOAD risk alleles and the utility of these combined markers for case-control prediction. Here we evaluate these loci in a large population-based sample to estimate PAF and explore the effects of additive and non-additive interactions on LOAD status prediction performance. Methods 2,419 samples from the Cache County Memory Study were genotyped for APOE and nine LOAD risk loci from AlzGene.org. We used logistic regression and ROC analysis to assess the LOAD status prediction performance of these loci using additive and non-additive models, and compared ORs and PAFs between AlzGene.org and Cache County. Results Odds ratios were comparable between Cache County and AlzGene.org when identical SNPs were genotyped. PAFs from AlzGene.org ranged from 2.25–37%; those from Cache County ranged from 0.05–20%. Including non-APOE alleles significantly improved LOAD status prediction performance (AUC = 0.80) over APOE alone (AUC = 0.78) when not constrained to an additive relationship (p < 0.03). We identified potential allelic interactions (p-values uncorrected): CD33-MS4A4E (Synergy Factor = 5.31; p < 0.003) and CLU-MS4A4E (SF = 3.81; p < 0.016). Conclusions While non-additive interactions between loci significantly improve diagnostic ability, the improvement does not reach the desired sensitivity or specificity for clinical use. Nevertheless, these results suggest that understanding gene-gene interactions may be important in resolving Alzheimer’s disease etiology. PMID:23954108

  18. Early Cognitive Deficits in Type 2 Diabetes: A Population-Based Study

    PubMed Central

    Marseglia, Anna; Fratiglioni, Laura; Laukka, Erika J.; Santoni, Giola; Pedersen, Nancy L.; Bäckman, Lars; Xu, Weili

    2016-01-01

    Evidence links type 2 diabetes to dementia risk. However, our knowledge on the initial cognitive deficits in diabetic individuals and the factors that might promote such deficits is still limited. This study aimed to identify the cognitive domains initially impaired by diabetes and the factors that play a role in this first stage. Within the population-based Swedish National Study on Aging and Care–Kungsholmen, 2305 cognitively intact participants aged ≥60 y were identified. Attention/working memory, perceptual speed, category fluency, letter fluency, semantic memory, and episodic memory were assessed. Diabetes (controlled and uncontrolled) and prediabetes were ascertained by clinicians, who also collected information on vascular disorders (hypertension, heart diseases, and stroke) and vascular risk factors (VRFs, including smoking and overweight/obesity). Data were analyzed with linear regression models. Overall, 196 participants (8.5%) had diabetes, of which 144 (73.5%) had elevated glycaemia (uncontrolled diabetes); 571 (24.8%) persons had prediabetes. In addition, diabetes, mainly uncontrolled, was related to lower performance in perceptual speed (β – 1.10 [95% CI – 1.98, – 0.23]), category fluency (β – 1.27 [95% CI – 2.52, – 0.03]), and digit span forward (β – 0.35 [95% CI – 0.54, – 0.17]). Critically, these associations were present only among APOE ɛ4 non–carriers. The associations of diabetes with perceptual speed and category fluency were present only among participants with VRFs or vascular disorders. Diabetes, especially uncontrolled diabetes, is associated with poorer performance in perceptual speed, category fluency, and attention/primary memory. VRFs, vascular disorders, and APOE status play a role in these associations. PMID:27314527

  19. Healthcare Costs Attributable to Hypertension: Canadian Population-Based Cohort Study.

    PubMed

    Weaver, Colin G; Clement, Fiona M; Campbell, Norm R C; James, Matthew T; Klarenbach, Scott W; Hemmelgarn, Brenda R; Tonelli, Marcello; McBrien, Kerry A

    2015-09-01

    Accurately documenting the current and future costs of hypertension is required to fully understand the potential economic impact of currently available and future interventions to prevent and treat hypertension. The objective of this work was to calculate the healthcare costs attributable to hypertension in Canada and to project these costs to 2020. Using population-based administrative data for the province of Alberta, Canada (>3 million residents) from 2002 to 2010, we identified individuals with and without diagnosed hypertension. We calculated their total healthcare costs and estimated costs attributable to hypertension using a regression model adjusting for comorbidities and sociodemographic factors. We then extrapolated hypertension-attributable costs to the rest of Canada and projected costs to the year 2020. Twenty-one percent of adults in Alberta had diagnosed hypertension in 2010, with a projected increase to 27% by 2020. The average individual with hypertension had annual healthcare costs of $5768, of which $2341 (41%) were attributed to hypertension. In Alberta, the healthcare costs attributable to hypertension were $1.4 billion in 2010. In Canada, the hypertension-attributable costs were estimated to be $13.9 billion in 2010, rising to $20.5 billion by 2020. The increase was ascribed to demographic changes (52%), increasing prevalence (16%), and increasing per-patient costs (32%). Hypertension accounts for a significant proportion of healthcare spending (10.2% of the Canadian healthcare budget) and is projected to rise even further. Interventions to prevent and treat hypertension may play a role in limiting this cost growth.

  20. The changing face of thyroid cancer in a population-based cohort.

    PubMed

    Pathak, K Alok; Leslie, William D; Klonisch, Thomas C; Nason, Richard W

    2013-08-01

    In North America, the incidence of thyroid cancer is increasing by over 6% per year. We studied the trends and factors influencing thyroid cancer incidence, its clinical presentation, and treatment outcome during 1970-2010 in a population-based cohort of 2306 consecutive thyroid cancers in Canada, that was followed up for a median period of 10.5 years. Disease-specific survival (DSS) and disease-free survival were estimated by the Kaplan-Meier method and the independent influence of various prognostic factors was evaluated by Cox proportional hazard models. Cumulative incidence of deaths resulting from thyroid cancer was calculated by competing risk analysis. A P-value <0.05 was considered to indicate statistical significance. The age standardized incidence of thyroid cancer by direct method increased from 2.52/100,000 (1970) to 9.37/100,000 (2010). Age at diagnosis, gender distribution, tumor size, and initial tumor stage did not change significantly during this period. The proportion of papillary thyroid cancers increased significantly (P < 0.001) from 58% (1970-1980) to 85.9% (2000-2010) while that of anaplastic cancer fell from 5.7% to 2.1% (P < 0.001). Ten-year DSS improved from 85.4% to 95.6%, and was adversely influenced by anaplastic histology (hazard ratio [HR] = 8.7; P < 0.001), male gender (HR = 1.8; P = 0.001), TNM stage IV (HR = 8.4; P = 0.001), incomplete surgical resection (HR = 2.4; P = 0.002), and age at diagnosis (HR = 1.05 per year; P < 0.001). There was a 373% increase in the incidence of thyroid cancer in Manitoba with a marked improvement in the thyroid cancer-specific survival that was independent of changes in patient demographics, tumor stage, or treatment practices, and is largely attributed to the declining proportion of anaplastic thyroid cancers.

  1. Pediatric Sleep Disorders and Special Educational Need at 8 Years: A Population-Based Cohort Study

    PubMed Central

    Rao, Trupti; Xu, Linzhi

    2012-01-01

    OBJECTIVES: To examine associations between sleep-disordered breathing (SDB) and behavioral sleep problems (BSPs) through 5 years of age and special educational need (SEN) at 8 years. METHODS: Parents in the Avon Longitudinal Study of Parents and Children reported on children’s snoring, witnessed apnea, and mouth-breathing at 6, 18, 30, 42, and 57 months, from which SDB symptom trajectories, or clusters, were derived. BSPs were based on report of ≥5 of 7 sleep behaviors at each of the 18-, 30-, 42-, and 57-month questionnaires. Parent report of SEN (yes/no) at 8 years was available for 11 049 children with SDB data and 11 467 children with BSP data. Multivariable logistic regression models were used to predict SEN outcome by SDB cluster and by cumulative report of SEN. RESULTS: Controlling for 16 putative confounders, previous history of SDB and BSPs was significantly associated with an SEN. BSPs were associated with a 7% increased odds of SEN (95% confidence interval [CI] 1.01–1.15), for each ∼1-year interval at which a BSP was reported. SDB, overall, was associated with a near 40% increased odds of SEN (95% CI 1.18–1.62). Children in the worst symptom cluster were 60% more likely to have an SEN (95% CI 1.23–2.08). CONCLUSIONS: In this population-based longitudinal study, history of either SDB or BSPs in the first 5 years of life was associated with increased likelihood of SEN at 8 years of age. Findings highlight the need for pediatric sleep disorder screening by early interventionists, early childhood educators, and health professionals. PMID:22945405

  2. Medication use and survival in diabetic patients with kidney cancer: A population-based cohort study.

    PubMed

    Nayan, Madhur; Macdonald, Erin M; Juurlink, David N; Austin, Peter C; Finelli, Antonio; Kulkarni, Girish S; Hamilton, Robert J

    2016-11-01

    Survival rates in kidney cancer have improved little over time, and diabetes may be an independent risk factor for poor survival in kidney cancer. We sought to determine whether medications with putative anti-neoplastic properties (statins, metformin and non-steroidal anti-inflammatory drugs (NSAIDs)) are associated with survival in diabetics with kidney cancer. We conducted a population-based cohort study utilizing linked healthcare databases in Ontario, Canada. Patients were aged 66 or older with newly diagnosed diabetes and a subsequent diagnosis of incident kidney cancer. Receipt of metformin, statins or NSAIDs was defined using prescription claims. The primary outcome was all-cause mortality and the secondary outcome was cancer-specific mortality. We used multivariable Cox proportional hazard regression, with medication use modeled with time-varying and cumulative exposure analyses to account for intermittent use. During the 14-year study period, we studied 613 patients. Current statin use was associated with a markedly reduced risk of death from any cause (adjusted hazard ratio 0.74; 95% CI 0.59-0.91) and death due to kidney cancer (adjusted hazard ratio 0.71; 95% CI 0.51-0.97). However, survival was not associated with current use of metformin or NSAIDs, or cumulative exposure to any of the medications studied. Among diabetic patients with kidney cancer, survival outcomes are associated with active statin use, rather than total cumulative use. These findings support the use of randomized trials to confirm whether diabetics with kidney cancer should be started on a statin at the time of cancer diagnosis to improve survival outcomes.

  3. Recurrent Clostridium difficile infection among Medicare patients in nursing homes: A population-based cohort study.

    PubMed

    Zilberberg, Marya D; Shorr, Andrew F; Jesdale, William M; Tjia, Jennifer; Lapane, Kate

    2017-03-01

    We explored the epidemiology and outcomes of Clostridium difficile infection (CDI) recurrence among Medicare patients in a nursing home (NH) whose CDI originated in acute care hospitals.We conducted a retrospective, population-based matched cohort combining Medicare claims with Minimum Data Set 3.0, including all hospitalized patients age ≥65 years transferred to an NH after hospitalization with CDI 1/2011-11/2012. Incident CDI was defined as ICD-9-CM code 008.45 with no others in prior 60 days. CDI recurrence was defined as (within 60 days of last day of CDI treatment): oral metronidazole, oral vancomycin, or fidaxomicin for ≥3 days in part D file; or an ICD-9-CM code for CDI (008.45) during a rehospitalization. Cox proportional hazards and linear models, adjusted for age, gender, race, and comorbidities, examined mortality within 60 days and excess hospital days and costs, in patients with recurrent CDI compared to those without.Among 14,472 survivors of index CDI hospitalization discharged to an NH, 4775 suffered a recurrence. Demographics and clinical characteristics at baseline were similar, as was the risk of death (24.2% with vs 24.4% without). Median number of hospitalizations was 2 (IQR 1-3) among those with and 0 (IQR 0-1) among those without recurrence. Adjusted excess hospital days per patient were 20.3 (95% CI 19.1-21.4) and Medicare reimbursements $12,043 (95% CI $11,469-$12,617) in the group with a recurrence.Although recurrent CDI did not increase the risk of death, it was associated with a far higher risk of rehospitalization, excess hospital days, and costs to Medicare.

  4. Long-term sedative use among community-dwelling adults: a population-based analysis

    PubMed Central

    Weymann, Deirdre; Gladstone, Emilie J.; Smolina, Kate; Morgan, Steven G.

    2017-01-01

    Background: Chronic use of benzodiazepines and benzodiazepine-like sedatives (z-drugs) presents substantial risks to people of all ages. We sought to assess trends in long-term sedative use among community-dwelling adults in British Columbia. Methods: Using population-based linked administrative databases, we examined longitudinal trends in age-standardized rates of sedative use among different age groups of community-dwelling adults (age ≥ 18 yr), from 2004 to 2013. For each calendar year, we classified adults as nonusers, short-term users, or long-term users of sedatives based on their patterns of sedative dispensation. For calendar year 2013, we applied cross-sectional analysis and estimated logistic regression models to identify health and socioeconomic risk factors associated with long-term sedative use. Results: More than half (53.4%) of long-term users of sedatives in British Columbia are between ages 18 and 64 years (young and middle-aged adults). From 2004 to 2013, long-term sedative use remained stable among adults more than 65 years of age (older adults) and increased slightly among young and middle-aged adults. Although the use of benzodiazepines decreased during the study period, the trend was offset by equal or greater increases in long-term use of z-drugs. Being an older adult, sick, poor and single were associated with increased odds of long-term sedative use. Interpretation: Despite efforts to stem such patterns of medication use, long-term use of sedatives increased in British Columbia between 2004 and 2013. This increase was driven largely by increased use among middle-aged adults. Future deprescribing efforts that target adults of all ages may help curb this trend.

  5. Aspirin Use Associated With Amyotrophic Lateral Sclerosis: a Total Population-Based Case-Control Study

    PubMed Central

    Tsai, Ching-Piao; Lin, Feng-Cheng; Lee, Johnny Kuang-Wu; Lee, Charles Tzu-Chi

    2015-01-01

    Background The association of aspirin use and nonsteroid anti-inflammatory drug (NSAID) use with amyotrophic lateral sclerosis (ALS) risk is unclear. This study determined whether use of any individual compound is associated with ALS risk by conducting a total population-based case-control study in Taiwan. Methods A total of 729 patients with newly diagnosed ALS who had a severely disabling disease certificate between January 1, 2002, and December 1, 2008, comprised the case group. These cases were compared with 7290 sex-, age-, residence-, and insurance premium-matched controls. Drug use by each Anatomical Therapeutic Chemical code was analyzed using conditional logistic regression models. False discovery rate (FDR)-adjusted P values were reported in order to avoid inflating false positives. Results Of the 1336 compounds, only the 266 with use cases exceeding 30 in our database were included in the screening analysis. Without controlling for steroid use, the analysis failed to reveal any compound that was inversely associated with ALS risk according to FDR criteria. After controlling for steroid use, we found use of the following compounds to be associated with ALS risk: aspirin, diphenhydramine (one of the antihistamines), and mefenamic acid (one of the NSAIDs). A multivariate analysis revealed that aspirin was independently inversely associated with ALS risk after controlling for diphenhydramine, mefenamic acid, and steroid use. The inverse association between aspirin and ALS was present predominately in patients older than 55 years. Conclusions The results of this study suggested that aspirin use might reduce the risk of ALS, and the benefit might be more prominent for older people. PMID:25721071

  6. Predicting mortality with biomarkers: a population-based prospective cohort study for elderly Costa Ricans

    PubMed Central

    2012-01-01

    Background Little is known about adult health and mortality relationships outside high-income nations, partly because few datasets have contained biomarker data in representative populations. Our objective is to determine the prognostic value of biomarkers with respect to total and cardiovascular mortality in an elderly population of a middle-income country, as well as the extent to which they mediate the effects of age and sex on mortality. Methods This is a prospective population-based study in a nationally representative sample of elderly Costa Ricans. Baseline interviews occurred mostly in 2005 and mortality follow-up went through December 2010. Sample size after excluding observations with missing values: 2,313 individuals and 564 deaths. Main outcome: prospective death rate ratios for 22 baseline biomarkers, which were estimated with hazard regression models. Results Biomarkers significantly predict future death above and beyond demographic and self-reported health conditions. The studied biomarkers account for almost half of the effect of age on mortality. However, the sex gap in mortality became several times wider after controlling for biomarkers. The most powerful predictors were simple physical tests: handgrip strength, pulmonary peak flow, and walking speed. Three blood tests also predicted prospective mortality: C-reactive protein (CRP), glycated hemoglobin (HbA1c), and dehydroepiandrosterone sulfate (DHEAS). Strikingly, high blood pressure (BP) and high total cholesterol showed little or no predictive power. Anthropometric measures also failed to show significant mortality effects. Conclusions This study adds to the growing evidence that blood markers for CRP, HbA1c, and DHEAS, along with organ-specific functional reserve indicators (handgrip, walking speed, and pulmonary peak flow), are valuable tools for identifying vulnerable elderly. The results also highlight the need to better understand an anomaly noted previously in other settings: despite the

  7. Genocide Exposure and Subsequent Suicide Risk: A Population-Based Study

    PubMed Central

    Levine, Stephen Z.; Levav, Itzhak; Yoffe, Rinat; Becher, Yifat; Pugachova, Inna

    2016-01-01

    The association between periods of genocide-related exposures and suicide risk remains unknown. Our study tests that association using a national population-based study design. The source population comprised of all persons born during1922-1945 in Nazi-occupied or dominated European nations, that immigrated to Israel by 1965, were identified in the Population Register (N = 220,665), and followed up for suicide to 2014, totaling 16,953,602 person-years. The population was disaggregated to compare a trauma gradient among groups that immigrated before (indirect, n = 20,612, 9%); during (partial direct, n = 17,037, 8%); or after (full direct, n = 183,016, 83%) exposure to the Nazi era. Also, the direct exposure groups were examined regarding pre- or post-natal exposure periods. Cox regression models were used to compute Hazard Ratios (HR) of suicide risk to compare the exposure groups, adjusting for confounding by gender, residential SES and history of psychiatric hospitalization. In the total population, only the partial direct exposure subgroup was at greater risk compared to the indirect exposure group (HR = 1.73, 95% CI, 1.10, 2.73; P < .05). That effect replicated in six sensitivity analyses. In addition, sensitivity analyses showed that exposure at ages 13 plus among females, and follow-up by years since immigration were associated with a greater risk; whereas in utero exposure among persons with no psychiatric hospitalization and early postnatal exposure among males were at a reduced risk. Tentative mechanisms impute biopsychosocial vulnerability and natural selection during early critical periods among males, and feelings of guilt and entrapment or defeat among females. PMID:26901411

  8. Characterization of mitochondrial haplogroups in a large population-based sample from the United States.

    PubMed

    Mitchell, Sabrina L; Goodloe, Robert; Brown-Gentry, Kristin; Pendergrass, Sarah A; Murdock, Deborah G; Crawford, Dana C

    2014-07-01

    Mitochondrial DNA (mtDNA) haplogroups are valuable for investigations in forensic science, molecular anthropology, and human genetics. In this study, we developed a custom panel of 61 mtDNA markers for high-throughput classification of European, African, and Native American/Asian mitochondrial haplogroup lineages. Using these mtDNA markers, we constructed a mitochondrial haplogroup classification tree and classified 18,832 participants from the National Health and Nutrition Examination Surveys (NHANES). To our knowledge, this is the largest study to date characterizing mitochondrial haplogroups in a population-based sample from the United States, and the first study characterizing mitochondrial haplogroup distributions in self-identified Mexican Americans separately from Hispanic Americans of other descent. We observed clear differences in the distribution of maternal genetic ancestry consistent with proposed admixture models for these subpopulations, underscoring the genetic heterogeneity of the United States Hispanic population. The mitochondrial haplogroup distributions in the other self-identified racial/ethnic groups within NHANES were largely comparable to previous studies. Mitochondrial haplogroup classification was highly concordant with self-identified race/ethnicity (SIRE) in non-Hispanic whites (94.8 %), but was considerably lower in admixed populations including non-Hispanic blacks (88.3 %), Mexican Americans (81.8 %), and other Hispanics (61.6 %), suggesting SIRE does not accurately reflect maternal genetic ancestry, particularly in populations with greater proportions of admixture. Thus, it is important to consider inconsistencies between SIRE and genetic ancestry when performing genetic association studies. The mitochondrial haplogroup data that we have generated, coupled with the epidemiologic variables in NHANES, is a valuable resource for future studies investigating the contribution of mtDNA variation to human health and disease.

  9. Severity of malocclusion in adolescents: populational-based study in the north of Minas Gerais, Brazil

    PubMed Central

    Silveira, Marise Fagundes; Freire, Rafael Silveira; Nepomuceno, Marcela Oliveira; Martins, Andrea Maria Eleutério de Barros Lima; Marcopito, Luiz Francisco

    2016-01-01

    ABSTRACT OBJECTIVE To identify the factors associated with severity of malocclusion in a population of adolescents. METHODS In this cross-sectional population-based study, the sample size (n = 761) was calculated considering a prevalence of malocclusion of 50.0%, with a 95% confidence level and a 5.0% precision level. The study adopted correction for the effect of delineation (deff = 2), and a 20.0% increase to offset losses and refusals. Multistage probability cluster sampling was adopted. Trained and calibrated professionals performed the intraoral examinations and interviews in households. The dependent variable (severity of malocclusion) was assessed using the Dental Aesthetic Index (DAI). The independent variables were grouped into five blocks: demographic characteristics, socioeconomic condition, use of dental services, health-related behavior and oral health subjective conditions. The ordinal logistic regression model was used to identify the factors associated with severity of malocclusion. RESULTS We interviewed and examined 736 adolescents (91.5% response rate), 69.9% of whom showed no abnormalities or slight malocclusion. Defined malocclusion was observed in 17.8% of the adolescents, being severe or very severe in 12.6%, with pressing or essential need of orthodontic treatment. The probabilities of greater severity of malocclusion were higher among adolescents who self-reported as black, indigenous, pardo or yellow, with lower per capita income, having harmful oral habits, negative perception of their appearance and perception of social relationship affected by oral health. CONCLUSIONS Severe or very severe malocclusion was more prevalent among socially disadvantaged adolescents, with reported harmful habits and perception of compromised esthetics and social relationships. Given that malocclusion can interfere with the self-esteem of adolescents, it is essential to improve public policy for the inclusion of orthodontic treatment among health care

  10. Opportunities for improving triple-negative breast cancer outcomes: results of a population-based study.

    PubMed

    Rapiti, Elisabetta; Pinaud, Kim; Chappuis, Pierre O; Viassolo, Valeria; Ayme, Aurélie; Neyroud-Caspar, Isabelle; Usel, Massimo; Bouchardy, Christine

    2017-03-01

    Triple-negative breast cancer (TNBC) is associated with a poor prognosis. Surgery, radiotherapy, chemotherapy, and referral for genetic counseling are the standard of care. We assessed TNBC prevalence, management, and outcome using data from the population-based Geneva cancer registry. 2591 women had a first invasive stage I-III breast cancer diagnosed between 2003 and 2011. We compared TNBC to other breast cancers (OBC) by χ(2) -test and logistic regression. Kaplan-Meier survival curves, up to 31-12-2014, were compared using log-rank test. TNBC risk of mortality overall (OS) and for breast cancer (BCSS) was evaluated through Cox models. Linkage with the Oncogenetics and Cancer Prevention Unit (OCPU) database of the Geneva University Hospitals provided genetic counseling information. TNBC patients (n = 192, 7.4%) were younger, more often born in Africa or Central-South America than OBC, had larger and more advanced tumors. 18% of TNBC patients did not receive chemotherapy. Thirty-one (17%) TNBC women consulted the OCPU, 39% among those aged <40 years. Ten-year survival was lower in TNBC than OBC (72% vs. 82% for BCSS; P < 0.001; 80% vs. 91% for OS; P < 0.001). The mortality risks remained significant after adjustment for other prognostic variables. The strongest determinants of mortality were age, place of birth, and lymph node status. A substantial proportion of TNBC patients in Geneva did not receive optimal care. Over 60% of eligible women did not receive genetic counseling and 18% did not receive chemotherapy. To improve TNBC prognosis, comprehensive care as recommended by standard guidelines should be offered to all patients.

  11. Occupational Chronic Obstructive Pulmonary Disease in a Danish Population-Based Study.

    PubMed

    Würtz, Else Toft; Schlünssen, Vivi; Malling, Tine Halsen; Hansen, Jens Georg; Omland, Øyvind

    2015-08-01

    The aim was to explore the impact of occupation on chronic obstructive pulmonary disease (COPD) in a cross-sectional population-based study among subjects aged 45 to 84 years. In a stratified sampling 89 general practitioners practices (GPP) in Denmark recruited 3106 males and 1636 females through the Danish Civil Registration System. COPD was defined by spirometry by the 2.5(th)-centile Lower Limit of Normal of FEV1 and FEV1/FVC. Information about smoking, occupational exposure and the respective occupations were obtained from questionnaires. Occupations followed the Danish adaptation of The International Standard Classification of Occupations, revision 1988 (DISCO-88). Exposure to vapour, gas, dust (organic and inorganic), and fume (VGDF) in each occupation (yes/no) was evaluated by two independent specialist in occupational medicine. Exposures were divided in no, low, medium, and high exposure as 0, < 5, 5-14, and ≥ 15 years in the job, respectively. Data was analysed by a mixed random effect logistic regression model. The age-standardised COPD study prevalence was 5.0%. Of 372 DISCO-88 codes 72 were identified with relevant exposure to VGDF. 46% of the participants reported at least one occupation with VGDF exposure. Adjusted for smoking, age, sex, and GPP a dose-dependent association of COPD was found among workers in jobs with high organic dust exposure, with OR 1.56 (95% CI 1.09-2.24). Restricted to agriculture the OR was 1.59 (95% CI: 1.08-2.33). No association was observed for workers in jobs with inorganic dust, fume/gas, or vapour exposures. In summary, occupational organic dust exposure was associated to the prevalence of COPD.

  12. Population-Based Study of QT Interval Prolongation in Patients with Rheumatoid Arthritis

    PubMed Central

    Chauhan, Krati; Ackerman, Michael J.; Crowson, Cynthia S.; Matteson, Eric L.; Gabriel, Sherine E.

    2015-01-01

    Background Patients with rheumatoid arthritis (RA) are at increased risk of cardiovascular morbidity and mortality. Heart rate corrected QT interval (QTc) (which is obtained from a 12-lead electrocardiogram (ECG) and reflects ventricular repolarization duration) is a strong predictor of cardiovascular mortality. Our primary purpose is to determine the impact of QTc prolongation on mortality in RA patients. Methods A population-based inception cohort of patients with RA fulfilling 1987 ACR criteria in 1988–2007 was identified, with an age- and sex-matched comparison cohort and followed until death, migration or 12-31-2008. Data were collected on ECG variables, medications known to prolong QT interval, electrolytes, cardiovascular risk factors and disease status and RA disease characteristics. Cox proportional hazards models were used to examine QTc prolongation as predictor of mortality. Results QTc prolongation prior to RA incidence/index date was similar in RA (15%) and non-RA (18%) subjects. During follow-up, the cumulative incidence of QTc prolongation was higher among RA (48% at 20 years after RA incidence) than non-RA (38% at 20 years after index date; p= 0.004). Idiopathic QTc prolongation (excluding prolongations explained by ECG changes, medications, etc.) was marginally associated with all-cause mortality (HR: 1.28; 95% CI: 0.91–1.81, p=0.16), but was not associated with cardiovascular mortality (HR: 1.10; 95% CI:0.43–2.86, p= 0.83) in RA. Conclusion RA patients have a significantly elevated risk of developing QTc prolongation. However, idiopathic prolonged QTc was only marginally associated with all-cause mortality in RA patients. The clinical implications of these findings in RA require further study. PMID:25572282

  13. Tamoxifen use and acute pancreatitis: A population-based cohort study

    PubMed Central

    Hsu, Fan-Gen; Hsieh, Yow-Wen; Sheu, Ming-Jyh; Lin, Che-Chen; Lin, Cheng-Li; Hsu, Chung Y.; Lee, Chang-Yin; Chang, Mei-Yin

    2017-01-01

    Background Several case reports have indicated that tamoxifen induced acute pancreatitis (AP); but no pharmacoepidemiological data support the claim. Therefore, we investigated whether tamoxifen use is correlated with the risk of AP in patients with breast cancer. Methods This population-based cohort study used the Taiwan National Health Insurance Research Database. A cohort of 22 005 patients aged ≥20 years with breast cancer from January 1, 2000 to December 31, 2009 was identified and the date of cancer diagnosis was set as the index date. The end point was developing AP during the follow-up. Hazard ratios (HRs) and 95% confidence intervals (CIs) were evaluated to determine the correlation between the risk of AP and tamoxifen use. Because the drug use varied over time, it was measured as a time-dependent covariate in the Cox proportional hazard model. The same approaches were applied in PS-matched cohorts. Results After adjustment for covariates and medication use including fluorouracil and doxorubicin, the risk of AP was not significant between tamoxifen users and tamoxifen nonusers (adjusted HR = 0.94, 95% CI = 0.74–1.19) in the non-matching cohorts. The results revealed no dose–response trend between tamoxifen use and the risk of AP (adjusted HR = 0.98, 95% CI = 0.96–1.00). The comorbidities DM and gallstones were associated with a significantly increased risk of AP. Similar trends were observed in PS-matched cohorts. Conclusions No significant correlation was observed between tamoxifen use and the risk of AP in patients with breast cancer. PMID:28291833

  14. HIV testing in national population-based surveys: experience from the Demographic and Health Surveys.

    PubMed Central

    Mishra, Vinod; Vaessen, Martin; Boerma, J. Ties; Arnold, Fred; Way, Ann; Barrere, Bernard; Cross, Anne; Hong, Rathavuth; Sangha, Jasbir

    2006-01-01

    OBJECTIVES: To describe the methods used in the Demographic and Health Surveys (DHS) to collect nationally representative data on the prevalence of human immunodeficiency virus (HIV) and assess the value of such data to country HIV surveillance systems. METHODS: During 2001-04, national samples of adult women and men in Burkina Faso, Cameroon, Dominican Republic, Ghana, Mali, Kenya, United Republic of Tanzania and Zambia were tested for HIV. Dried blood spot samples were collected for HIV testing, following internationally accepted ethical standards. The results for each country are presented by age, sex, and urban versus rural residence. To estimate the effects of non-response, HIV prevalence among non-responding males and females was predicted using multivariate statistical models for those who were tested, with a common set of predictor variables. RESULTS: Rates of HIV testing varied from 70% among Kenyan men to 92% among women in Burkina Faso and Cameroon. Despite large differences in HIV prevalence between the surveys (1-16%), fairly consistent patterns of HIV infection were observed by age, sex and urban versus rural residence, with considerably higher rates in urban areas and in women, especially at younger ages. Analysis of non-response bias indicates that although predicted HIV prevalence tended to be higher in non-tested males and females than in those tested, the overall effects of non-response on the observed national estimates of HIV prevalence are insignificant. CONCLUSIONS: Population-based surveys can provide reliable, direct estimates of national and regional HIV seroprevalence among men and women irrespective of pregnancy status. Survey data greatly enhance surveillance systems and the accuracy of national estimates in generalized epidemics. PMID:16878227

  15. Digoxin use after diagnosis of breast cancer and survival: a population-based cohort study.

    PubMed

    Karasneh, Reema A; Murray, Liam J; Mc Menamin, Úna C; Hughes, Carmel M; Cardwell, Chris R

    2015-06-01

    Digoxin has been shown to have an estrogenic effect and is associated with increased risk of gynecomastia and estrogen-sensitive cancers such as breast and uterus cancer. These findings, particularly recent observations of increased breast cancer risk, raise questions about the safety of digoxin use in breast cancer patients. Therefore, we investigated whether digoxin use after breast cancer diagnosis increased the risk of breast cancer-specific mortality in breast cancer patients. A cohort of 17,842 breast cancer patients newly diagnosed from 1998 to 2009 was identified from English cancer registries (from the National Cancer Data Repository). This cohort was linked to the UK Clinical Practice Research Datalink (to provide digoxin and other prescription records) and to the Office of National Statistics mortality data (to identify breast cancer-specific deaths). Using time-dependent Cox regression models, unadjusted and adjusted hazard ratios (HR) and 95 % confidence intervals (CIs) were calculated for the association between post-diagnostic exposure to digoxin and breast cancer-specific and all-cause mortality. In 17,842 breast cancer patients, there were 2219 breast cancer-specific deaths. Digoxin users appeared to have increased breast cancer-specific mortality compared with non-users (HR 1.73; 95 % CI 1.39-2.15) but this association was entirely attenuated after adjustment for potential confounders (adjusted HR 0.91; 95 % CI 0.72-1.14). In this large population-based breast cancer cohort study, there was little evidence of an increase in breast cancer-specific mortality with digoxin use after diagnosis. These results provide some reassurance that digoxin use is safe in breast cancer patients.

  16. Tuberculosis infection in primary Sjögren's syndrome: a nationwide population-based study.

    PubMed

    Chang, Yu-Sheng; Liu, Chia-Jen; Ou, Shou-Ming; Hu, Yu-Wen; Chen, Tzeng-Ji; Lee, Hui-Ting; Chang, Chi-Ching; Chou, Chung-Tei

    2014-03-01

    Primary Sjögren's syndrome (pSS) is a systemic autoimmune disease and may complicate with interstitial lung disease. The risk of Mycobacterium tuberculosis (TB) infection in patients with pSS has not been determined. This nationwide population-based study aimed to explore the incidence and risk factors of TB infection in patients with pSS. We identified 4,822 pSS patients from the Taiwan National Health Insurance database and compared the incidence rates of TB infection in these patients with 48,220 randomly selected age-, sex-, and comorbidity-matched subjects without pSS. The Cox proportional hazard model was used to identify risk factors for TB in patients with pSS. The risk of TB was higher in the pSS cohort than in the control cohort with an incidence rate ratio (IRR) of 1.58 (95% confidence interval [95% CI] 1.13-2.18, p = 0.006). The risk factors for TB in the pSS cohort were age ≥60 years (hazard ratio [HR] 3.22, 95% CI 1.78-5.84; p < 0.001), and corticosteroid usage, which had a dose-dependent effect in the pSS patients compared to the nonusers (daily prednisolone dose or equivalent less than 5 mg/day: HR 2.34; p = 0.020, 95% CI 1.14-4.78; 5 mg/day to less than 10 mg/day: HR 4.79, 95% CI 2.15-10.68; p < 0.001; 10 mg/day or more: HR 12.19, 95% CI 4.42-33.63; p < 0.001). Patients with pSS had a higher risk of pulmonary TB in Taiwan, which was related to age ≥60 years and corticosteroid usage.

  17. The Association Between Peptic Ulcer Disease and Ischemic Stroke: A Population-Based Longitudinal Study.

    PubMed

    Cheng, Tain-Junn; Guo, How-Ran; Chang, Chia-Yu; Weng, Shih-Feng; Li, Pi-I; Wang, Jhi-Joung; Wu, Wen-Shiann

    2016-05-01

    Stroke is a common cause of death worldwide, but about 30% of ischemic stroke (IS) patients have no identifiable contributing risk factors. Because peptic ulcer disease (PUD) and vascular events share some common risk factors, we conducted a population-based study to evaluate the association between PUD and IS.We followed up a representative sample of 1 million residents of Taiwan using the National Health Insurance Research Database from 1997 to 2011. We defined patients who received medications for PUD and had related diagnosis codes as the PUD group, and a reference group matched by age and sex was sampled from those who did not have PUD. We also collected data on medical history and monthly income. The events of IS occurred after enrollment were compared between the 2 groups. The data were analyzed using Cox proportional hazard models at the 2-tailed significant level of 0.05.The PUD group had higher income and prevalence of hypertension, diabetes mellitus (DM), heart disease, and hyperlipidemia. They also had a higher risk of developing IS with an adjusted hazard ratio of 1.31 (95% confidence interval: 1.20-1.41). Other independent risk factors included male sex, older age, lower income, and co-morbidity of hypertension, diabetes mellitus (DM), and heart disease.PUD is a risk factor for IS, independent of conventional risk factors such as male sex, older age, lower income, and co-morbidity of hypertension, DM, and heart disease. Prevention strategies taking into account PUD should be developed and evaluated.

  18. Gout increases risk of fracture: A nationwide population-based cohort study.

    PubMed

    Tzeng, Huey-En; Lin, Che-Chen; Wang, I-Kuan; Huang, Po-Hao; Tsai, Chun-Hao

    2016-08-01

    There is still debate on whether high uric acid increases bone mineral density (BMD) against osteoporotic fracture or bone resorption caused by gout inflammation. This study aimed to evaluate whether gout offers a protective effect on bone health or not. We conducted a nationwide population-based retrospective cohort study to evaluate the association between gout history and risk factors of fracture.A retrospective cohort study was designed using the claim data from Longitudinal Health Insurance Database (LHID). A total of 43,647 subjects with gout and a cohort of 87,294 comparison subjects without gout were matched in terms of age and sex between 2001 and 2009, and the data were followed until December 31, 2011. The primary outcome of the study was the fracture incidence, and the impacts of gout on fracture risks were analyzed using the Cox proportional hazards model.After an 11-year follow-up period, 6992 and 11,412 incidents of fracture were reported in gout and comparison cohorts, respectively. The overall incidence rate of fracture in individuals with gout was nearly 23%, which was higher than that in individuals without gout (252 vs 205 per 10,000 person-years) at an adjusted hazard ratio of 1.17 (95% confidence interval = 1.14-1.21). Age, sex, and fracture-associated comorbidities were adjusted accordingly. As for fracture locations, patients with gout were found at significant higher fracture risks for upper/lower limbs and spine fractures. In gout patient, the user of allopurinol or benzbromarone has significantly lower risk of facture than nonusers.Gout history is considered as a risk factor for fractures, particularly in female individuals and fracture sites located at the spine or upper/lower limbs.

  19. Measurement of the Omega0(c) lifetime

    SciTech Connect

    Iori, M.; Ayan, A.S.; Akgun, U.; Alkhazov, G.; Amaro-Reyes, J.; Atamantchouk, A.G.; Balatz, M.Y.; Blanco-Covarrubias, A.; Bondar, N.F.; Cooper, P.S.; Dauwe, L.J.; /Ball State U. /Bogazici U. /Carnegie Mellon U. /Rio de Janeiro, CBPF /Fermilab /Serpukhov, IHEP /Beijing, Inst. High Energy Phys. /Moscow, ITEP /Heidelberg, Max Planck Inst. /Moscow State U. /St. Petersburg, INP

    2007-01-01

    The authors report a precise measurement of the {Omega}{sub c}{sup 0} lifetime. The data were taken by the SELEX (E781) experiment using 600 GeV/c {Sigma}{sup -}, {pi}{sup -} and p beams. The measurement has been made using 83 {+-} 19 reconstructed {Omega}{sub c}{sup 0} in the {Omega}{sup -} {pi}{sup -}{pi}{sup +}{pi}{sup +} and {Omega}{sup -} {pi}{sup +} decay modes. The lifetime of the {Omega}{sub c}{sup 0} is measured to be 65 {+-} 13(stat) {+-} 9(sys) fs.

  20. Fluorescence Lifetime Techniques in Medical Applications

    PubMed Central

    Marcu, Laura

    2012-01-01

    This article presents an overview of time-resolved (lifetime) fluorescence techniques used in biomedical diagnostics. In particular, we review the development of time-resolved fluorescence spectroscopy (TRFS) and fluorescence lifetime imaging (FLIM) instrumentation and associated methodologies which allows for in vivo characterization and diagnosis of biological tissues. Emphasis is placed on the translational research potential of these techniques and on evaluating whether intrinsic fluorescence signals provide useful contrast for the diagnosis of human diseases including cancer (gastrointestinal tract, lung, head and neck, and brain), skin and eye diseases, and atherosclerotic cardiovascular disease. PMID:22273730

  1. An approach for longer lifetime MCFCs

    SciTech Connect

    Matsumoto, Masaru; Tatsumi, Masahiko; Hayano, Takuro

    1996-12-31

    For entering into commercialization of MCFC power plants in the beginning of the 21st century, we will devote to research for increasing lifetime as long as 40,000 hours with cell performance decay rate of 0.25 %/1000hrs as the target in FY 1999. This paper will discuss on our approach for longer lifetime MCFCs through electrolyte-loss management and NiO precipitation management as well as micro-structural control of electrodes and matrix plates. Cell voltage decay rate will be estimated by simulation through series of experiments on accelerated conditions.

  2. Scaling of multiexciton lifetimes in semiconductor nanocrystals

    NASA Astrophysics Data System (ADS)

    Klimov, V. I.; McGuire, J. A.; Schaller, R. D.; Rupasov, V. I.

    2008-05-01

    Ultrafast multiexciton decay via Auger recombination is a major impediment for prospective applications of semiconductor nanocrystals (NCs) in lasing and solar cells enabled by carrier multiplication. One important unexplored aspect of Auger recombination is the scaling of multiexciton lifetimes with the number of excitons per NC. To address this question, we analyze multiexciton dynamics in PbSe and CdSe NCs. We observe that these two systems show a distinct difference in scaling of multiexciton lifetimes, which can be explained in terms of a difference in symmetries of high-order multiexcitons resulting from significant disparity in degeneracies of the lowest-energy quantized states.

  3. B lifetimes and mixing at the Tevatron

    SciTech Connect

    Bedeschi, Franco; /INFN, Pisa

    2005-05-01

    The authors present recent results on b-hadron lifetimes and mixing obtained from the analysis of the data collected at the Tevatron Collider by the CDF and D0 Collaborations in the period 2002-2004. Many lifetime measurements have been updated since the Summer 2004 conferences, sometimes improving significantly the accuracy. Likewise the measurement of the B{sub d} oscillation frequency has been updated. New limits on the B{sub s} oscillation frequency have been determined using for the first time Run II data.

  4. Lifetime evaluation of CMOS mixed signal devices

    NASA Astrophysics Data System (ADS)

    Linder, A.; Furlong, J.; Malone, N.; Madajian, D.; Kar-Roy, A.

    2012-10-01

    New foundry processes continue to produce smaller features and new designs. These new devices must be screened to validate their usefulness for long lifetime use. The Failure-in-Time analysis in conjunction with foundry qualification information can be used to evaluate foundry device lifetimes. This analysis is a helpful tool when zero failure life tests are performed. The reliability of the device is estimated by applying the failure rate to the use conditions. JEDEC publications.2,3,4 are the industry accepted methods.

  5. Fluorescent Lifetime Spectroscopy in Random Media

    NASA Astrophysics Data System (ADS)

    Hutchinson, Christina Laura

    Recently, an abundance of near-infrared phosphorescent and fluorescent probes have been developed whose lifetime is sensitive to changes in the local environment. The lifetime of these probes can be readily determined in a dilute, non-scattering media using conventional time- and frequency-domain techniques. From the lifetime, the concentration of metabolites can be found using the Stern-Volmer relationship. However, in highly scattering media such as tissues and particulate process streams, measurement of lifetime is complicated by the time delay associated with light scatter. In this dissertation, frequency-domain measurements of photon migration are developed for measuring fluorescent lifetimes independent of absorption and scattering properties of tissues and other random media. The measurement consists of launching, onto the surface of the medium, excitation light whose intensity is sinusoidally modulated at megahertz frequencies. The fluorescent light generated within the medium is intensity modulated at the same frequency, but phase-shifted and amplitude demodulated relative to the incident excitation source. In addition, the excitation light is also phase-shifted and amplitude demodulated relative to the incident excitation source. From Green's function analysis, finite element computations, and experimental measurements of fluorescent phase-shift and amplitude demodulation, we show it is possible to determine fluorophore lifetime of common laser dyes in a tissue mimicking phantom. Furthermore, the finite element computations of excitation and fluorescent light fluence show that when the fluorophore is uniformly distributed within a medium, signals re-emitted at the surface do not originate from significant depths if its lifetime is greater than the photon migration time associated with scatter. Consequently, this research points to the development of short-lived fluorescent compounds for biodiagnostics using properly referenced frequency

  6. Association between chronic osteomyelitis and deep-vein thrombosis. Analysis of a nationwide population-based registry.

    PubMed

    Lin, T-Y; Chen, Y-G; Huang, W-Y; Lin, C-L; Peng, C-L; Sung, F-C; Kao, C-H

    2014-09-02

    Studies on the association between chronic osteomyelitis and deep vein thrombosis (DVT) and pulmonary thromboembolism (PE) are scarce. The aim of this study was to analyse a nationwide population-based database for association between DVT or PE after a diagnosis of chronic osteomyelitis. This nationwide population-based cohort study was based on data obtained from the Taiwan National Health Insurance Database from 1998 to 2008, with a follow-up period extending to the end of 2010. We identified patients with chronic osteomyelitis using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes. The patients with chronic osteomyelitis and comparison controls were selected by 1:1 matching on a propensity score. The propensity score was calculated by a logistic regression to estimate the probability of the treatment assignment given the baseline variables including age, sex, and Charlson comorbidity index score. We analysed the risks of DVT and PE by using Cox proportional hazards regression models, including sex, age, and comorbidities. In total, 24,335 chronic osteomyelitis patients and 24,335 controls were enrolled in the study. The risk of developing DVT was 2.49-fold in patients with chronic osteomyelitis compared with the comparison cohort, after adjusting for age, sex, and comorbidities. The multiplicative increased risks of DVT were also significant in patients with chronic osteomyelitis with any comorbidity. In conclusion, physicians should consider chronic osteomyelitis in their evaluation of risk factors for DVT.

  7. Development of a Late-Life Dementia Prediction Index with Supervised Machine Learning in the Population-Based CAIDE Study

    PubMed Central

    Pekkala, Timo; Hall, Anette; Lötjönen, Jyrki; Mattila, Jussi; Soininen, Hilkka; Ngandu, Tiia; Laatikainen, Tiina; Kivipelto, Miia; Solomon, Alina

    2016-01-01

    Background and objective: This study aimed to develop a late-life dementia prediction model using a novel validated supervised machine learning method, the Disease State Index (DSI), in the Finnish population-based CAIDE study. Methods: The CAIDE study was based on previous population-based midlife surveys. CAIDE participants were re-examined twice in late-life, and the first late-life re-examination was used as baseline for the present study. The main study population included 709 cognitively normal subjects at first re-examination who returned to the second re-examination up to 10 years later (incident dementia n = 39). An extended population (n = 1009, incident dementia 151) included non-participants/non-survivors (national registers data). DSI was used to develop a dementia index based on first re-examination assessments. Performance in predicting dementia was assessed as area under the ROC curve (AUC). Results: AUCs for DSI were 0.79 and 0.75 for main and extended populations. Included predictors were cognition, vascular factors, age, subjective memory complaints, and APOE genotype. Conclusion: The supervised machine learning method performed well in identifying comprehensive profiles for predicting dementia development up to 10 years later. DSI could thus be useful for identifying individuals who are most at risk and may benefit from dementia prevention interventions. PMID:27802228

  8. Automated reference region extraction and population-based input function for brain [11C]TMSX PET image analyses

    PubMed Central

    Rissanen, Eero; Tuisku, Jouni; Luoto, Pauliina; Arponen, Eveliina; Johansson, Jarkko; Oikonen, Vesa; Parkkola, Riitta; Airas, Laura; Rinne, Juha O

    2015-01-01

    [11C]TMSX ([7-N-methyl-11C]-(E)-8-(3,4,5-trimethoxystyryl)-1,3,7-trimethylxanthine) is a selective adenosine A2A receptor (A2AR) radioligand. In the central nervous system (CNS), A2AR are linked to dopamine D2 receptor function in striatum, but they are also important modulators of inflammation. The golden standard for kinetic modeling of brain [11C]TMSX positron emission tomography (PET) is to obtain arterial input function via arterial blood sampling. However, this method is laborious, prone to errors and unpleasant for study subjects. The aim of this work was to evaluate alternative input function acquisition methods for brain [11C]TMSX PET imaging. First, a noninvasive, automated method for the extraction of gray matter reference region using supervised clustering (SCgm) was developed. Second, a method for obtaining a population-based arterial input function (PBIF) was implemented. These methods were created using data from 28 study subjects (7 healthy controls, 12 multiple sclerosis patients, and 9 patients with Parkinson's disease). The results with PBIF correlated well with original plasma input, and the SCgm yielded similar results compared with cerebellum as a reference region. The clustering method for extracting reference region and the population-based approach for acquiring input for dynamic [11C]TMSX brain PET image analyses appear to be feasible and robust methods, that can be applied in patients with CNS pathology. PMID:25370856

  9. Automated reference region extraction and population-based input function for brain [(11)C]TMSX PET image analyses.

    PubMed

    Rissanen, Eero; Tuisku, Jouni; Luoto, Pauliina; Arponen, Eveliina; Johansson, Jarkko; Oikonen, Vesa; Parkkola, Riitta; Airas, Laura; Rinne, Juha O

    2015-01-01

    [(11)C]TMSX ([7-N-methyl-(11)C]-(E)-8-(3,4,5-trimethoxystyryl)-1,3,7-trimethylxanthine) is a selective adenosine A2A receptor (A2AR) radioligand. In the central nervous system (CNS), A2AR are linked to dopamine D2 receptor function in striatum, but they are also important modulators of inflammation. The golden standard for kinetic modeling of brain [(11)C]TMSX positron emission tomography (PET) is to obtain arterial input function via arterial blood sampling. However, this method is laborious, prone to errors and unpleasant for study subjects. The aim of this work was to evaluate alternative input function acquisition methods for brain [(11)C]TMSX PET imaging. First, a noninvasive, automated method for the extraction of gray matter reference region using supervised clustering (SCgm) was developed. Second, a method for obtaining a population-based arterial input function (PBIF) was implemented. These methods were created using data from 28 study subjects (7 healthy controls, 12 multiple sclerosis patients, and 9 patients with Parkinson's disease). The results with PBIF correlated well with original plasma input, and the SCgm yielded similar results compared with cerebellum as a reference region. The clustering method for extracting reference region and the population-based approach for acquiring input for dynamic [(11)C]TMSX brain PET image analyses appear to be feasible and robust methods, that can be applied in patients with CNS pathology.

  10. The impact of truncation and missing family links in population-based registers on familial risk estimates.

    PubMed

    Leu, Monica; Czene, Kamila; Reilly, Marie

    2007-12-15

    Family history information is often incomplete in population-based disease registers because of truncation and/or missing family links. In this study, the authors simulated complete populations of related individuals with realistic age, family structure, and incidence rates. After mimicking the realities of register-based data, such as left truncation of family history and missing family links due to death, the authors explored recovery of familial association parameters from standard epidemiologic models. Truncation of family history produced almost no bias for a familial risk of 2 and 50 years of follow-up, but it had a dramatic impact when the familial risk was 10. The age distribution of disease and the magnitude of background incidence rates also affected family history loss and thus the magnitude of bias. One can safeguard against bias by starting follow-up later, with the number of registration years to be ignored in the analysis depending on the value of familial risk. The missing familial links due to death had no effect, except when there was differential mortality for cases with and without a family history of disease. In summary, truncation, and to a lesser extent missing family links, induces bias in familial risk estimates from population-based registers.

  11. Asthma and Attention-Deficit/Hyperactivity Disorder: A Nationwide Population-Based Prospective Cohort Study

    ERIC Educational Resources Information Center

    Chen, Mu-Hong; Su, Tung-Ping; Chen, Ying-Sheue; Hsu, Ju-Wei; Huang, Kai-Lin; Chang, Wen-Han; Chen, Tzeng-Ji; Bai, Ya-Mei

    2013-01-01

    Background: Previous cross-sectional studies have suggested an association between asthma and attention-deficit/hyperactivity disorder (ADHD), but the temporal relationship was not determined. Using a nationwide population-based prospective case-control cohort study (1:4, age-/gender-matched), we hypothesized that asthma in infanthood or early…

  12. HIV/AIDS Misconceptions among Latinos: Findings from a Population-Based Survey of California Adults

    ERIC Educational Resources Information Center

    Ritieni, Assunta; Moskowitz, Joel; Tholandi, Maya

    2008-01-01

    Misconceptions about HIV/AIDS among Latino adults (N=454) in California were examined using data from a population-based telephone survey conducted in 2000. Common misconceptions concerning modes of HIV transmission included transmission via mosquito or animal bite (64.1%), public facilities (48.3%), or kissing someone on the cheek (24.8%). A…

  13. Epilepsy Among Children and Adolescents with Autism Spectrum Disorders: A Population-Based Study

    ERIC Educational Resources Information Center

    Jokiranta, Elina; Sourander, Andre; Suominen, Auli; Timonen-Soivio, Laura; Brown, Alan S.; Sillanpää, Matti

    2014-01-01

    The present population-based study examines associations between epilepsy and autism spectrum disorders (ASD). The cohort includes register data of 4,705 children born between 1987 and 2005 and diagnosed as cases of childhood autism, Asperger's syndrome or pervasive developmental disorders--not otherwise specified. Each case was matched to four…

  14. Methods of Suicide among Cancer Patients: A Nationwide Population-Based Study

    ERIC Educational Resources Information Center

    Chung, Kuo-Hsuan; Lin, Herng-Ching

    2010-01-01

    A 3-year nationwide population-based data set was used to explore methods of suicide (violent vs. nonviolent) and possible contributing factors among cancer patients in Taiwan. A total of 1,065 cancer inpatients who committed suicide were included as our study sample. The regression shows that those who had genitourinary cancer were 0.55 times (p…

  15. Sexually Transmitted Diseases and Risk Behaviors among California Farmworkers: Results from a Population-Based Survey

    ERIC Educational Resources Information Center

    Brammeier, Monique; Chow, Joan M.; Samuel, Michael C.; Organista, Kurt C.; Miller, Jamie; Bolan, Gail

    2008-01-01

    Context: The prevalence of sexually transmitted diseases and associated risk behaviors among California farmworkers is not well described. Purpose: To estimate the prevalence of sexually transmitted diseases (STDs) and associated risk behaviors among California farmworkers. Methods: Cross-sectional analysis of population-based survey data from 6…

  16. Psychological Abuse between Parents: Associations with Child Maltreatment from a Population-Based Sample

    ERIC Educational Resources Information Center

    Chang, Jen Jen; Theodore, Adrea D.; Martin, Sandra L.; Runyan, Desmond K.

    2008-01-01

    Objective: This study examined the association between partner psychological abuse and child maltreatment perpetration. Methods: This cross-sectional study examined a population-based sample of mothers with children aged 0-17 years in North and South Carolina (n = 1,149). Mothers were asked about the occurrence of potentially neglectful or abusive…

  17. Mortality in Adults with Moderate to Profound Intellectual Disability: A Population-Based Study

    ERIC Educational Resources Information Center

    Tyrer, F.; Smith, L. K.; McGrother, C. W.

    2007-01-01

    Background: People with intellectual disability (ID) experience a variety of health inequalities compared with the general population including higher mortality rates. This is the first UK population-based study to measure the extent of excess mortality in people with ID compared with the general population. Method: Indirectly standardized…

  18. Long-Term Benefits of Full-Day Kindergarten: A Longitudinal Population-Based Study

    ERIC Educational Resources Information Center

    Brownell, M. D.; Nickel, N. C.; Chateau, D.; Martens, P. J.; Taylor, C.; Crockett, L.; Katz, A.; Sarkar, J.; Burland, E.; Goh, C. Y.

    2015-01-01

    In the first longitudinal, population-based study of full-day kindergarten (FDK) outcomes beyond primary school in Canada, we used linked administrative data to follow 15 kindergarten cohorts (n ranging from 112 to 736) up to grade 9. Provincial assessments conducted in grades 3, 7, and 8 and course marks and credits earned in grade 9 were…

  19. A Population-Based Study of Preschoolers' Food Neophobia and Its Associations with Food Preferences

    ERIC Educational Resources Information Center

    Russell, Catherine Georgina; Worsley, Anthony

    2008-01-01

    Objective: This cross-sectional study was designed to investigate the relationships between food preferences, food neophobia, and children's characteristics among a population-based sample of preschoolers. Design: A parent-report questionnaire. Setting: Child-care centers, kindergartens, playgroups, day nurseries, and swimming centers. Subjects:…

  20. Risk of fragility fracture among patients with sarcoidosis: a population-based study 1976-2013.

    PubMed

    Ungprasert, P; Crowson, C S; Matteson, E L

    2017-02-16

    Incidence of fragility fracture of a population-based cohort of 345 patients with sarcoidosis was compared with age and sex-matched comparators. The incidence of fragility fracture was higher among patients with sarcoidosis with hazard ratio (HR) of 2.18.

  1. Understanding Disabled Childhoods: What Can We Learn from Population-Based Studies?

    ERIC Educational Resources Information Center

    Emerson, Eric

    2012-01-01

    This article illustrates the potential value of undertaking secondary analyses of large-scale population-based survey data to better inform our understanding of disabled childhoods. It is argued that while such approaches can never address the lived experience of growing up with disability, they can provide valuable insights into the ways in which…

  2. Associated Medical Disorders and Disabilities in Children with Autistic Disorder: A Population-Based Study

    ERIC Educational Resources Information Center

    Kielinen, Marko; Rantala, Heikki; Timonen, Eija; Linna, Sirkka-Liisa; Moilanen, Irma

    2004-01-01

    A population-based survey was conducted among 152,732 Finnish children and adolescents aged under 16 years and living in northern Finland. Diagnoses and associated medical conditions were derived from the hospital and institutional records of this area. One hundred and eighty-seven children with DSM-IV autistic disorder were identified. Associated…

  3. Relationship Status among Parents of Children with Autism Spectrum Disorders: A Population-Based Study

    ERIC Educational Resources Information Center

    Freedman, Brian H.; Kalb, Luther G.; Zablotsky, Benjamin; Stuart, Elizabeth A.

    2012-01-01

    Despite speculation about an 80% divorce rate among parents of children with an Autism Spectrum Disorder (ASD), very little empirical and no epidemiological research has addressed the issue of separation and divorce among this population. Data for this study was taken from the 2007 National Survey of Children's Health, a population-based,…

  4. Evaluating Nicotine Replacement Therapy and Stage-Based Therapies in a Population-Based Effectiveness Trial

    ERIC Educational Resources Information Center

    Velicer, Wayne F.; Friedman, Robert H.; Fava, Joseph L.; Gulliver, Suzy B.; Keller, Stefan; Sun, Xiaowu; Ramelson, Harley; Prochaska, James O.

    2006-01-01

    Pharmacological interventions for smoking cessation are typically evaluated using volunteer samples (efficacy trials) but should also be evaluated in population-based trials (effectiveness trials). Nicotine replacement therapy (NRT) alone and in combination with behavioral interventions was evaluated on a population of smokers from a New England…

  5. Paediatric cancer stage in population-based cancer registries: the Toronto consensus principles and guidelines.

    PubMed

    Gupta, Sumit; Aitken, Joanne F; Bartels, Ute; Brierley, James; Dolendo, Mae; Friedrich, Paola; Fuentes-Alabi, Soad; Garrido, Claudia P; Gatta, Gemma; Gospodarowicz, Mary; Gross, Thomas; Howard, Scott C; Molyneux, Elizabeth; Moreno, Florencia; Pole, Jason D; Pritchard-Jones, Kathy; Ramirez, Oscar; Ries, Lynn A G; Rodriguez-Galindo, Carlos; Shin, Hee Young; Steliarova-Foucher, Eva; Sung, Lillian; Supriyadi, Eddy; Swaminathan, Rajaraman; Torode, Julie; Vora, Tushar; Kutluk, Tezer; Frazier, A Lindsay

    2016-04-01

    Population-based cancer registries generate estimates of incidence and survival that are essential for cancer surveillance, research, and control strategies. Although data on cancer stage allow meaningful assessments of changes in cancer incidence and outcomes, stage is not recorded by most population-based cancer registries. The main method of staging adult cancers is the TNM classification. The criteria for staging paediatric cancers, however, vary by diagnosis, have evolved over time, and sometimes vary by cooperative trial group. Consistency in the collection of staging data has therefore been challenging for population-based cancer registries. We assembled key experts and stakeholders (oncologists, cancer registrars, epidemiologists) and used a modified Delphi approach to establish principles for paediatric cancer stage collection. In this Review, we make recommendations on which staging systems should be adopted by population-based cancer registries for the major childhood cancers, including adaptations for low-income countries. Wide adoption of these guidelines in registries will ease international comparative incidence and outcome studies.

  6. Big data for population-based cancer research: the integrated cancer information and surveillance system.

    PubMed

    Meyer, Anne-Marie; Olshan, Andrew F; Green, Laura; Meyer, Adrian; Wheeler, Stephanie B; Basch, Ethan; Carpenter, William R

    2014-01-01

    The Integrated Cancer Information and Surveillance System (ICISS) facilitates population-based cancer research by developing extensive information technology systems that can link and manage large data sets. Taking an interdisciplinary 'team science' approach, ICISS has developed data, systems, and methods that allow researchers to better leverage the power of big data to improve population health.

  7. A Population-Based Longitudinal Study of Depression in Children with Developmental Disabilities in Manitoba

    ERIC Educational Resources Information Center

    Shooshtari, Shahin; Brownell, Marni; Dik, Natalia; Chateau, Dan; Yu, C. T.; Mills, Rosemary S. L.; Burchill, Charles A.; Wetzel, Monika

    2014-01-01

    In this population-based study, prevalence of depression was estimated and compared between children with and without developmental disability (DD). Twelve years of administrative data were linked to identify a cohort of children with DD living in the Canadian province of Manitoba. Children in the study cohort were matched with children without DD…

  8. Understanding Risk and Protective Factors for Child Maltreatment: The Value of Integrated, Population-Based Data

    ERIC Educational Resources Information Center

    Putnam-Hornstein, Emily; Needell, Barbara; Rhodes, Anne E.

    2013-01-01

    In this article, we argue for expanded efforts to integrate administrative data systems as a "practical strategy" for developing a richer understanding of child abuse and neglect. Although the study of child maltreatment is often critiqued for being atheoretical, we believe that a more pressing concern is the absence of population-based and…

  9. Oceanic eddy detection and lifetime forecast using machine learning methods

    NASA Astrophysics Data System (ADS)

    Ashkezari, Mohammad D.; Hill, Christopher N.; Follett, Christopher N.; Forget, Gaël.; Follows, Michael J.

    2016-12-01

    We report a novel altimetry-based machine learning approach for eddy identification and characterization. The machine learning models use daily maps of geostrophic velocity anomalies and are trained according to the phase angle between the zonal and meridional components at each grid point. The trained models are then used to identify the corresponding eddy phase patterns and to predict the lifetime of a detected eddy structure. The performance of the proposed method is examined at two dynamically different regions to demonstrate its robust behavior and region independency.

  10. Lifetimes and structure of excited states of 115Sb

    NASA Astrophysics Data System (ADS)

    Lobach, Yu. N.; Bucurescu, D.

    1998-06-01

    Lifetimes of excited states of 115Sb were measured by the Doppler shift attenuation method in the (α,2nγ) reaction at Eα = 27.2 MeV. The experimental level scheme and the electromagnetic transition probabilities have been interpreted in terms of the interacting boson-fermion model. A reasonable agreement with the experiment was obtained for the positive-parity states. The experimental data also show the applicability of the cluster-vibrational model for the mixing of two 9/2+ states having different intrinsic configurations.

  11. MSFC solar activity predictions for satellite orbital lifetime estimation

    NASA Technical Reports Server (NTRS)

    Fuler, H. C.; Lundquist, C. A.; Vaughan, W. W.

    1979-01-01

    The procedure to predict solar activity indexes for use in upper atmosphere density models is given together with an example of the performance. The prediction procedure employs a least square linear regression model to generate the predicted smoothed vinculum R sub 13 and geomagnetic vinculum A sub p(13) values. Linear regression equations are then employed to compute corresponding vinculum F sub 10.7(13) solar flux values from the predicted vinculum R sub 13 values. The output is issued principally for satellite orbital lifetime estimations.

  12. B Physics Results from the Tevatron: Lifetimes and Rare Decays

    SciTech Connect

    Lewis, Jonathan; /Fermilab

    2009-01-01

    With data samples of up to 2 fb{sup -1} of p{bar p} interactions at {radical}s = 1960 GeV, the CDF and D0 experiments are beginning to make precision measurements of the lifetime of bottom hadrons not produced in e{sup +}e{sup -} colliders operating at the {Upsilon}(4S) and set limits on the branching ratios of many decay modes that are predicted to be rare or forbidden under the standard model. Both sets of measurements are providing limits on physics beyond the standard model.

  13. Electron Beam Lifetime in SPEAR3: Measurement and Simulation

    SciTech Connect

    Corbett, J.; Huang, X.; Lee, M.; Lui, P.; Sayyar-Rodsari, B.; /Pavilon Tech., Austin

    2007-12-19

    In this paper we report on electron beam lifetime measurements as a function of scraper position, RF voltage and bunch fill pattern in SPEAR3. We then outline development of an empirical, macroscopic model using the beam-loss rate equation. By identifying the dependence of loss coefficients on accelerator and beam parameters, a numerically-integrating simulator can be constructed to compute beam decay with time. In a companion paper, the simulator is used to train a parametric, non-linear dynamics model for the system [1].

  14. Lifetime measurements and shape coexistence in {sup 144}Dy

    SciTech Connect

    Procter, M. G.; Cullen, D. M.; Niclasen, B.; Mason, P. J. R.; Rigby, S. V.; Dare, J. A.; Lumley, N. M.; Scholey, C.; Greenlees, P. T.; Jakobsson, U.; Jones, P. M.; Julin, R.; Juutinen, S.; Ketelhut, S.; Leino, M.; Nyman, M.; Puurunen, A.; Rahkila, P.; Ruotsalainen, P.; Saren, J.

    2010-05-15

    The known level scheme of {sup 144}Dy has been extended and lifetime measurements have been made with the recoil-distance Doppler-shift method. Reduced transition probabilities and deformations have been determined for four low-lying transitions. These states form part of the first observed band crossing, giving information on the change in nuclear deformation resulting from the rearrangement of h{sub 11/2} protons in the nucleus. Two bands built upon excited 10{sup +} states have been assigned pi(h{sub 11/2}){sup 2} prolate and nu(h{sub 11/2}){sup -2} oblate configurations with tau=12(2)ps and 0.01lifetimes are reasoned to be a result of shape coexistence at low energy and moderate spin. A known four-quasiparticle dipole band has been extended to higher spin and lifetime measurements suggest a long-lived bandhead state. In this case, the excited states in the band may be consistent with a shears model interpretation of a magnetic dipole rotor. However, the measured B(M1)/B(E2) branching ratios reveal a larger than expected deformed rotational component compared with that in the analogous band in the lower mass isotone {sup 142}Gd.

  15. Lifetime measurements and shape coexistence in Dy144

    NASA Astrophysics Data System (ADS)

    Procter, M. G.; Cullen, D. M.; Scholey, C.; Niclasen, B.; Mason, P. J. R.; Rigby, S. V.; Dare, J. A.; Dewald, A.; Greenlees, P. T.; Iwasaki, H.; Jakobsson, U.; Jones, P. M.; Julin, R.; Juutinen, S.; Ketelhut, S.; Leino, M.; Lumley, N. M.; Möller, O.; Nyman, M.; Peura, P.; Pissulla, T.; Puurunen, A.; Rahkila, P.; Rother, W.; Ruotsalainen, P.; Sarén, J.; Sorri, J.; Uusitalo, J.

    2010-05-01

    The known level scheme of Dy144 has been extended and lifetime measurements have been made with the recoil-distance Doppler-shift method. Reduced transition probabilities and deformations have been determined for four low-lying transitions. These states form part of the first observed band crossing, giving information on the change in nuclear deformation resulting from the rearrangement of h11/2 protons in the nucleus. Two bands built upon excited 10+ states have been assigned π(h11/2)2 prolate and ν(h11/2)-2 oblate configurations with τ=12(2)ps and 0.01<τ≲16ns, respectively. These long lifetimes are reasoned to be a result of shape coexistence at low energy and moderate spin. A known four-quasiparticle dipole band has been extended to higher spin and lifetime measurements suggest a long-lived bandhead state. In this case, the excited states in the band may be consistent with a shears model interpretation of a magnetic dipole rotor. However, the measured B(M1)/B(E2) branching ratios reveal a larger than expected deformed rotational component compared with that in the analogous band in the lower mass isotone Gd142.

  16. Reducing variability in short term orbital lifetime prediction

    N