Sample records for general missing pattern

  1. Identifying patterns of item missing survey data using latent groups: an observational study

    PubMed Central

    McElwee, Paul; Nathan, Andrea; Burton, Nicola W; Turrell, Gavin

    2017-01-01

    Objectives To examine whether respondents to a survey of health and physical activity and potential determinants could be grouped according to the questions they missed, known as ‘item missing’. Design Observational study of longitudinal data. Setting Residents of Brisbane, Australia. Participants 6901 people aged 40–65 years in 2007. Materials and methods We used a latent class model with a mixture of multinomial distributions and chose the number of classes using the Bayesian information criterion. We used logistic regression to examine if participants’ characteristics were associated with their modal latent class. We used logistic regression to examine whether the amount of item missing in a survey predicted wave missing in the following survey. Results Four per cent of participants missed almost one-fifth of the questions, and this group missed more questions in the middle of the survey. Eighty-three per cent of participants completed almost every question, but had a relatively high missing probability for a question on sleep time, a question which had an inconsistent presentation compared with the rest of the survey. Participants who completed almost every question were generally younger and more educated. Participants who completed more questions were less likely to miss the next longitudinal wave. Conclusions Examining patterns in item missing data has improved our understanding of how missing data were generated and has informed future survey design to help reduce missing data. PMID:29084795

  2. Identifying patterns of item missing survey data using latent groups: an observational study.

    PubMed

    Barnett, Adrian G; McElwee, Paul; Nathan, Andrea; Burton, Nicola W; Turrell, Gavin

    2017-10-30

    To examine whether respondents to a survey of health and physical activity and potential determinants could be grouped according to the questions they missed, known as 'item missing'. Observational study of longitudinal data. Residents of Brisbane, Australia. 6901 people aged 40-65 years in 2007. We used a latent class model with a mixture of multinomial distributions and chose the number of classes using the Bayesian information criterion. We used logistic regression to examine if participants' characteristics were associated with their modal latent class. We used logistic regression to examine whether the amount of item missing in a survey predicted wave missing in the following survey. Four per cent of participants missed almost one-fifth of the questions, and this group missed more questions in the middle of the survey. Eighty-three per cent of participants completed almost every question, but had a relatively high missing probability for a question on sleep time, a question which had an inconsistent presentation compared with the rest of the survey. Participants who completed almost every question were generally younger and more educated. Participants who completed more questions were less likely to miss the next longitudinal wave. Examining patterns in item missing data has improved our understanding of how missing data were generated and has informed future survey design to help reduce missing data. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  3. Noniterative approach to the missing data problem in coherent diffraction imaging by phase retrieval.

    PubMed

    Nakajima, Nobuharu

    2010-07-20

    When a very intense beam is used for illuminating an object in coherent x-ray diffraction imaging, the intensities at the center of the diffraction pattern for the object are cut off by a beam stop that is utilized to block the intense beam. Until now, only iterative phase-retrieval methods have been applied to object reconstruction from a single diffraction pattern with a deficiency of central data due to a beam stop. As an alternative method, I present a noniterative solution in which an interpolation method based on the sampling theorem for the missing data is used for object reconstruction with our previously proposed phase-retrieval method using an aperture-array filter. Computer simulations demonstrate the reconstruction of a complex-amplitude object from a single diffraction pattern with a missing data area, which is generally difficult to treat with the iterative methods because a nonnegativity constraint cannot be used for such an object.

  4. Evaluation of missing value methods for predicting ambient BTEX concentrations in two neighbouring cities in Southwestern Ontario Canada

    NASA Astrophysics Data System (ADS)

    Miller, Lindsay; Xu, Xiaohong; Wheeler, Amanda; Zhang, Tianchu; Hamadani, Mariam; Ejaz, Unam

    2018-05-01

    High density air monitoring campaigns provide spatial patterns of pollutant concentrations which are integral in exposure assessment. Such analysis can assist with the determination of links between air quality and health outcomes, however, problems due to missing data can threaten to compromise these studies. This research evaluates four methods; mean value imputation, inverse distance weighting (IDW), inter-species ratios, and regression, to address missing spatial concentration data ranging from one missing data point up to 50% missing data. BTEX (benzene, toluene, ethylbenzene, and xylenes) concentrations were measured in Windsor and Sarnia, Ontario in the fall of 2005. Concentrations and inter-species ratios were generally similar between the two cities. Benzene (B) was observed to be higher in Sarnia, whereas toluene (T) and the T/B ratios were higher in Windsor. Using these urban, industrialized cities as case studies, this research demonstrates that using inter-species ratios or regression of the data for which there is complete information, along with one measured concentration (i.e. benzene) to predict for missing concentrations (i.e. TEX) results in good agreement between predicted and measured values. In both cities, the general trend remains that best agreement is observed for the leave-one-out scenario, followed by 10% and 25% missing, and the least agreement for the 50% missing cases. In the absence of any known concentrations IDW can provide reasonable agreement between observed and estimated concentrations for the BTEX species, and was superior over mean value imputation which was not able to preserve the spatial trend. The proposed methods can be used to fill in missing data, while preserving the general characteristics and rank order of the data which are sufficient for epidemiologic studies.

  5. Patterns of missing data in the use of the endometriosis symptom diary.

    PubMed

    Seitz, Christian; Lanius, Vivian; Lippert, Susanne; Gerlinger, Christoph; Haberland, Claudia; Oehmke, Frank; Tinneberg, Hans-Rudolf

    2018-06-08

    Endometriosis is a common, chronic condition in women of reproductive age that is characterized by the presence of functional endometriotic lesions outside the uterus. The Endometriosis Symptom Diary (ESD) is an electronic patient-reported outcome (ePRO) instrument that assesses women's experience of endometriosis symptoms, with pain scored using a 0-10 numeric rating scale. This study investigated patterns of data missing from the ESD in the VALEPRO study. Post hoc analyses of missing data were conducted. Of 272 participants using the ESD, 26.5% had no missing diary entries, 46.7% had > 0-5% of entries missing, 13.2% had > 5-10% of entries missing and 13.6% had > 10% of entries missing over the entire study period. The duration of missing episodes (defined as ≥1 consecutive days with missing diary entries) was generally short; most (81.4%) were 1 day. The difference in mean worst pain scores between missing and complete episodes per participant was - 0.1, suggesting that missing episodes were not related to severity of pain. Entries were significantly more likely to be missing on Fridays (18.5%) and Saturdays (22.9%) compared with other days of the week (p < 0.0001). Participants in the USA had significantly more long missing episodes than those in Germany (proportions of missing episodes longer than 1 day, 22.6 and 10.5%, respectively; p < 0.0001). The proportions of women with ≥1 missing entry were 50.0, 70.2 and 79.8% for women with elementary education, secondary education, and a college or university education, respectively. The proportions of women with ≥1 missing entry were similar for those with and without children (72.2 and 74.3%, respectively). Most participants were highly compliant with entering data in the ESD and the amount of missing data was low. Entries were significantly more likely to be missing on Fridays and Saturdays compared with other days of the week, and participants in the USA had significantly more long missing episodes than participants in Germany. Clinicaltrials.gov, NCT01643122 , registered 4 July 2012.

  6. Missing data within a quantitative research study: How to assess it, treat it, and why you should care.

    PubMed

    Bannon, William

    2015-04-01

    Missing data typically refer to the absence of one or more values within a study variable(s) contained in a dataset. The development is often the result of a study participant choosing not to provide a response to a survey item. In general, a greater number of missing values within a dataset reflects a greater challenge to the data analyst. However, if researchers are armed with just a few basic tools, they can quite effectively diagnose how serious the issue of missing data is within a dataset, as well as prescribe the most appropriate solution. Specifically, the keys to effectively assessing and treating missing data values within a dataset involve specifying how missing data will be defined in a study, assessing the amount of missing data, identifying the pattern of the missing data, and selecting the best way to treat the missing data values. I will touch on each of these processes and provide a brief illustration of how the validity of study findings are at great risk if missing data values are not treated effectively. ©2015 American Association of Nurse Practitioners.

  7. Application of pattern mixture models to address missing data in longitudinal data analysis using SPSS.

    PubMed

    Son, Heesook; Friedmann, Erika; Thomas, Sue A

    2012-01-01

    Longitudinal studies are used in nursing research to examine changes over time in health indicators. Traditional approaches to longitudinal analysis of means, such as analysis of variance with repeated measures, are limited to analyzing complete cases. This limitation can lead to biased results due to withdrawal or data omission bias or to imputation of missing data, which can lead to bias toward the null if data are not missing completely at random. Pattern mixture models are useful to evaluate the informativeness of missing data and to adjust linear mixed model (LMM) analyses if missing data are informative. The aim of this study was to provide an example of statistical procedures for applying a pattern mixture model to evaluate the informativeness of missing data and conduct analyses of data with informative missingness in longitudinal studies using SPSS. The data set from the Patients' and Families' Psychological Response to Home Automated External Defibrillator Trial was used as an example to examine informativeness of missing data with pattern mixture models and to use a missing data pattern in analysis of longitudinal data. Prevention of withdrawal bias, omitted data bias, and bias toward the null in longitudinal LMMs requires the assessment of the informativeness of the occurrence of missing data. Missing data patterns can be incorporated as fixed effects into LMMs to evaluate the contribution of the presence of informative missingness to and control for the effects of missingness on outcomes. Pattern mixture models are a useful method to address the presence and effect of informative missingness in longitudinal studies.

  8. Longitudinal data analysis with non-ignorable missing data.

    PubMed

    Tseng, Chi-hong; Elashoff, Robert; Li, Ning; Li, Gang

    2016-02-01

    A common problem in the longitudinal data analysis is the missing data problem. Two types of missing patterns are generally considered in statistical literature: monotone and non-monotone missing data. Nonmonotone missing data occur when study participants intermittently miss scheduled visits, while monotone missing data can be from discontinued participation, loss to follow-up, and mortality. Although many novel statistical approaches have been developed to handle missing data in recent years, few methods are available to provide inferences to handle both types of missing data simultaneously. In this article, a latent random effects model is proposed to analyze longitudinal outcomes with both monotone and non-monotone missingness in the context of missing not at random. Another significant contribution of this article is to propose a new computational algorithm for latent random effects models. To reduce the computational burden of high-dimensional integration problem in latent random effects models, we develop a new computational algorithm that uses a new adaptive quadrature approach in conjunction with the Taylor series approximation for the likelihood function to simplify the E-step computation in the expectation-maximization algorithm. Simulation study is performed and the data from the scleroderma lung study are used to demonstrate the effectiveness of this method. © The Author(s) 2012.

  9. What's missing in missing data? Omissions in survey responses among parents of children with advanced cancer.

    PubMed

    Rosenberg, Abby R; Dussel, Veronica; Orellana, Liliana; Kang, Tammy; Geyer, J Russel; Feudtner, Chris; Wolfe, Joanne

    2014-08-01

    Missing data is a common phenomenon with survey-based research; patterns of missing data may elucidate why participants decline to answer certain questions. To describe patterns of missing data in the Pediatric Quality of Life and Evaluation of Symptoms Technology (PediQUEST) study, and highlight challenges in asking sensitive research questions. Cross-sectional, survey-based study embedded within a randomized controlled trial. Three large children's hospitals: Dana-Farber/Boston Children's Cancer and Blood Disorders Center (DF/BCCDC); Children's Hospital of Philadelphia (CHOP); and Seattle Children's Hospital (SCH). At the time of their child's enrollment, parents completed the Survey about Caring for Children with Cancer (SCCC), including demographics, perceptions of prognosis, treatment goals, quality of life, and psychological distress. Eighty-six of 104 parents completed surveys (83% response). The proportion of missing data varied by question type. While 14 parents (16%) left demographic fields blank, over half (n=48; 56%) declined to answer at least one question about their child's prognosis, especially life expectancy. The presence of missing data was unrelated to the child's diagnosis, time from progression, time to death, or parent distress (p>0.3 for each). Written explanations in survey margins suggested that addressing a child's life expectancy is particularly challenging for parents. Parents of children with cancer commonly refrain from answering questions about their child's prognosis, however, they may be more likely to address general cure likelihood than explicit life expectancy. Understanding acceptability of sensitive questions in survey-based research will foster higher quality palliative care research.

  10. Is Spending More Time Associated With Less Missed Care?: A Comparison of Time Use and Missed Care Across 15 Nursing Units at 2 Hospitals.

    PubMed

    McNair, Norma; Baird, Jennifer; Grogan, Tristan R; Walsh, Catherine M; Liang, Li-Jung; Worobel-Luk, Pamela; Needleman, Jack; Nuckols, Teryl K

    2016-09-01

    The aim of this study is to examine the relationship between nursing time use and perceptions of missed care. Recent literature has highlighted the problem of missed nursing care, but little is known about how nurses' time use patterns are associated with reports of missed care. In 15 nursing units at 2 hospitals, we assessed registered nurse (RN) perceptions of missed care, observed time use by RNs, and examined the relationship between time spent and degree of missed care at the nursing unit level. Patterns of time use were similar across hospitals, with 25% of time spent on documentation. For 6 different categories of nursing tasks, no association was detected between time use, including time spent on documentation, and the degree of missed care at the nursing unit level. Nursing time use cannot fully explain variation in missed care across nursing units. Further work is needed to account for patterns of missed care.

  11. Best Practices for Missing Data Management in Counseling Psychology

    ERIC Educational Resources Information Center

    Schlomer, Gabriel L.; Bauman, Sheri; Card, Noel A.

    2010-01-01

    This article urges counseling psychology researchers to recognize and report how missing data are handled, because consumers of research cannot accurately interpret findings without knowing the amount and pattern of missing data or the strategies that were used to handle those data. Patterns of missing data are reviewed, and some of the common…

  12. Abnormal Complex Auditory Pattern Analysis in Schizophrenia Reflected in an Absent Missing Stimulus Mismatch Negativity.

    PubMed

    Salisbury, Dean F; McCathern, Alexis G

    2016-11-01

    The simple mismatch negativity (MMN) to tones deviating physically (in pitch, loudness, duration, etc.) from repeated standard tones is robustly reduced in schizophrenia. Although generally interpreted to reflect memory or cognitive processes, simple MMN likely contains some activity from non-adapted sensory cells, clouding what process is affected in schizophrenia. Research in healthy participants has demonstrated that MMN can be elicited by deviations from abstract auditory patterns and complex rules that do not cause sensory adaptation. Whether persons with schizophrenia show abnormalities in the complex MMN is unknown. Fourteen schizophrenia participants and 16 matched healthy underwent EEG recording while listening to 400 groups of 6 tones 330 ms apart, separated by 800 ms. Occasional deviant groups were missing the 4th or 6th tone (50 groups each). Healthy participants generated a robust response to a missing but expected tone. The schizophrenia group was significantly impaired in activating the missing stimulus MMN, generating no significant activity at all. Schizophrenia affects the ability of "primitive sensory intelligence" and pre-attentive perceptual mechanisms to form implicit groups in the auditory environment. Importantly, this deficit must relate to abnormalities in abstract complex pattern analysis rather than sensory problems in the disorder. The results indicate a deficit in parsing of the complex auditory scene which likely impacts negatively on successful social navigation in schizophrenia. Knowledge of the location and circuit architecture underlying the true novelty-related MMN and its pathophysiology in schizophrenia will help target future interventions.

  13. Breast Cancer and Modifiable Lifestyle Factors in Argentinean Women: Addressing Missing Data in a Case-Control Study

    PubMed Central

    Coquet, Julia Becaria; Tumas, Natalia; Osella, Alberto Ruben; Tanzi, Matteo; Franco, Isabella; Diaz, Maria Del Pilar

    2016-01-01

    A number of studies have evidenced the effect of modifiable lifestyle factors such as diet, breastfeeding and nutritional status on breast cancer risk. However, none have addressed the missing data problem in nutritional epidemiologic research in South America. Missing data is a frequent problem in breast cancer studies and epidemiological settings in general. Estimates of effect obtained from these studies may be biased, if no appropriate method for handling missing data is applied. We performed Multiple Imputation for missing values on covariates in a breast cancer case-control study of Córdoba (Argentina) to optimize risk estimates. Data was obtained from a breast cancer case control study from 2008 to 2015 (318 cases, 526 controls). Complete case analysis and multiple imputation using chained equations were the methods applied to estimate the effects of a Traditional dietary pattern and other recognized factors associated with breast cancer. Physical activity and socioeconomic status were imputed. Logistic regression models were performed. When complete case analysis was performed only 31% of women were considered. Although a positive association of Traditional dietary pattern and breast cancer was observed from both approaches (complete case analysis OR=1.3, 95%CI=1.0-1.7; multiple imputation OR=1.4, 95%CI=1.2-1.7), effects of other covariates, like BMI and breastfeeding, were only identified when multiple imputation was considered. A Traditional dietary pattern, BMI and breastfeeding are associated with the occurrence of breast cancer in this Argentinean population when multiple imputation is appropriately performed. Multiple Imputation is suggested in Latin America’s epidemiologic studies to optimize effect estimates in the future. PMID:27892664

  14. Missing data exploration: highlighting graphical presentation of missing pattern.

    PubMed

    Zhang, Zhongheng

    2015-12-01

    Functions shipped with R base can fulfill many tasks of missing data handling. However, because the data volume of electronic medical record (EMR) system is always very large, more sophisticated methods may be helpful in data management. The article focuses on missing data handling by using advanced techniques. There are three types of missing data, that is, missing completely at random (MCAR), missing at random (MAR) and not missing at random (NMAR). This classification system depends on how missing values are generated. Two packages, Multivariate Imputation by Chained Equations (MICE) and Visualization and Imputation of Missing Values (VIM), provide sophisticated functions to explore missing data pattern. In particular, the VIM package is especially helpful in visual inspection of missing data. Finally, correlation analysis provides information on the dependence of missing data on other variables. Such information is useful in subsequent imputations.

  15. METHODS FOR CLUSTERING TIME SERIES DATA ACQUIRED FROM MOBILE HEALTH APPS.

    PubMed

    Tignor, Nicole; Wang, Pei; Genes, Nicholas; Rogers, Linda; Hershman, Steven G; Scott, Erick R; Zweig, Micol; Yvonne Chan, Yu-Feng; Schadt, Eric E

    2017-01-01

    In our recent Asthma Mobile Health Study (AMHS), thousands of asthma patients across the country contributed medical data through the iPhone Asthma Health App on a daily basis for an extended period of time. The collected data included daily self-reported asthma symptoms, symptom triggers, and real time geographic location information. The AMHS is just one of many studies occurring in the context of now many thousands of mobile health apps aimed at improving wellness and better managing chronic disease conditions, leveraging the passive and active collection of data from mobile, handheld smart devices. The ability to identify patient groups or patterns of symptoms that might predict adverse outcomes such as asthma exacerbations or hospitalizations from these types of large, prospectively collected data sets, would be of significant general interest. However, conventional clustering methods cannot be applied to these types of longitudinally collected data, especially survey data actively collected from app users, given heterogeneous patterns of missing values due to: 1) varying survey response rates among different users, 2) varying survey response rates over time of each user, and 3) non-overlapping periods of enrollment among different users. To handle such complicated missing data structure, we proposed a probability imputation model to infer missing data. We also employed a consensus clustering strategy in tandem with the multiple imputation procedure. Through simulation studies under a range of scenarios reflecting real data conditions, we identified favorable performance of the proposed method over other strategies that impute the missing value through low-rank matrix completion. When applying the proposed new method to study asthma triggers and symptoms collected as part of the AMHS, we identified several patient groups with distinct phenotype patterns. Further validation of the methods described in this paper might be used to identify clinically important patterns in large data sets with complicated missing data structure, improving the ability to use such data sets to identify at-risk populations for potential intervention.

  16. Examining solutions to missing data in longitudinal nursing research.

    PubMed

    Roberts, Mary B; Sullivan, Mary C; Winchester, Suzy B

    2017-04-01

    Longitudinal studies are highly valuable in pediatrics because they provide useful data about developmental patterns of child health and behavior over time. When data are missing, the value of the research is impacted. The study's purpose was to (1) introduce a three-step approach to assess and address missing data and (2) illustrate this approach using categorical and continuous-level variables from a longitudinal study of premature infants. A three-step approach with simulations was followed to assess the amount and pattern of missing data and to determine the most appropriate imputation method for the missing data. Patterns of missingness were Missing Completely at Random, Missing at Random, and Not Missing at Random. Missing continuous-level data were imputed using mean replacement, stochastic regression, multiple imputation, and fully conditional specification (FCS). Missing categorical-level data were imputed using last value carried forward, hot-decking, stochastic regression, and FCS. Simulations were used to evaluate these imputation methods under different patterns of missingness at different levels of missing data. The rate of missingness was 16-23% for continuous variables and 1-28% for categorical variables. FCS imputation provided the least difference in mean and standard deviation estimates for continuous measures. FCS imputation was acceptable for categorical measures. Results obtained through simulation reinforced and confirmed these findings. Significant investments are made in the collection of longitudinal data. The prudent handling of missing data can protect these investments and potentially improve the scientific information contained in pediatric longitudinal studies. © 2017 Wiley Periodicals, Inc.

  17. Missing data exploration: highlighting graphical presentation of missing pattern

    PubMed Central

    2015-01-01

    Functions shipped with R base can fulfill many tasks of missing data handling. However, because the data volume of electronic medical record (EMR) system is always very large, more sophisticated methods may be helpful in data management. The article focuses on missing data handling by using advanced techniques. There are three types of missing data, that is, missing completely at random (MCAR), missing at random (MAR) and not missing at random (NMAR). This classification system depends on how missing values are generated. Two packages, Multivariate Imputation by Chained Equations (MICE) and Visualization and Imputation of Missing Values (VIM), provide sophisticated functions to explore missing data pattern. In particular, the VIM package is especially helpful in visual inspection of missing data. Finally, correlation analysis provides information on the dependence of missing data on other variables. Such information is useful in subsequent imputations. PMID:26807411

  18. Recurrent Neural Networks for Multivariate Time Series with Missing Values.

    PubMed

    Che, Zhengping; Purushotham, Sanjay; Cho, Kyunghyun; Sontag, David; Liu, Yan

    2018-04-17

    Multivariate time series data in practical applications, such as health care, geoscience, and biology, are characterized by a variety of missing values. In time series prediction and other related tasks, it has been noted that missing values and their missing patterns are often correlated with the target labels, a.k.a., informative missingness. There is very limited work on exploiting the missing patterns for effective imputation and improving prediction performance. In this paper, we develop novel deep learning models, namely GRU-D, as one of the early attempts. GRU-D is based on Gated Recurrent Unit (GRU), a state-of-the-art recurrent neural network. It takes two representations of missing patterns, i.e., masking and time interval, and effectively incorporates them into a deep model architecture so that it not only captures the long-term temporal dependencies in time series, but also utilizes the missing patterns to achieve better prediction results. Experiments of time series classification tasks on real-world clinical datasets (MIMIC-III, PhysioNet) and synthetic datasets demonstrate that our models achieve state-of-the-art performance and provide useful insights for better understanding and utilization of missing values in time series analysis.

  19. A pattern-mixture model approach for handling missing continuous outcome data in longitudinal cluster randomized trials.

    PubMed

    Fiero, Mallorie H; Hsu, Chiu-Hsieh; Bell, Melanie L

    2017-11-20

    We extend the pattern-mixture approach to handle missing continuous outcome data in longitudinal cluster randomized trials, which randomize groups of individuals to treatment arms, rather than the individuals themselves. Individuals who drop out at the same time point are grouped into the same dropout pattern. We approach extrapolation of the pattern-mixture model by applying multilevel multiple imputation, which imputes missing values while appropriately accounting for the hierarchical data structure found in cluster randomized trials. To assess parameters of interest under various missing data assumptions, imputed values are multiplied by a sensitivity parameter, k, which increases or decreases imputed values. Using simulated data, we show that estimates of parameters of interest can vary widely under differing missing data assumptions. We conduct a sensitivity analysis using real data from a cluster randomized trial by increasing k until the treatment effect inference changes. By performing a sensitivity analysis for missing data, researchers can assess whether certain missing data assumptions are reasonable for their cluster randomized trial. Copyright © 2017 John Wiley & Sons, Ltd.

  20. Best practices for missing data management in counseling psychology.

    PubMed

    Schlomer, Gabriel L; Bauman, Sheri; Card, Noel A

    2010-01-01

    This article urges counseling psychology researchers to recognize and report how missing data are handled, because consumers of research cannot accurately interpret findings without knowing the amount and pattern of missing data or the strategies that were used to handle those data. Patterns of missing data are reviewed, and some of the common strategies for dealing with them are described. The authors provide an illustration in which data were simulated and evaluate 3 methods of handling missing data: mean substitution, multiple imputation, and full information maximum likelihood. Results suggest that mean substitution is a poor method for handling missing data, whereas both multiple imputation and full information maximum likelihood are recommended alternatives to this approach. The authors suggest that researchers fully consider and report the amount and pattern of missing data and the strategy for handling those data in counseling psychology research and that editors advise researchers of this expectation.

  1. Examining Solutions to Missing Data in Longitudinal Nursing Research

    PubMed Central

    Roberts, Mary B.; Sullivan, Mary C.; Winchester, Suzy B.

    2017-01-01

    Purpose Longitudinal studies are highly valuable in pediatrics because they provide useful data about developmental patterns of child health and behavior over time. When data are missing, the value of the research is impacted. The study’s purpose was to: (1) introduce a 3-step approach to assess and address missing data; (2) illustrate this approach using categorical and continuous level variables from a longitudinal study of premature infants. Methods A three-step approach with simulations was followed to assess the amount and pattern of missing data and to determine the most appropriate imputation method for the missing data. Patterns of missingness were Missing Completely at Random, Missing at Random, and Not Missing at Random. Missing continuous-level data were imputed using mean replacement, stochastic regression, multiple imputation, and fully conditional specification. Missing categorical-level data were imputed using last value carried forward, hot-decking, stochastic regression, and fully conditional specification. Simulations were used to evaluate these imputation methods under different patterns of missingness at different levels of missing data. Results The rate of missingness was 16–23% for continuous variables and 1–28% for categorical variables. Fully conditional specification imputation provided the least difference in mean and standard deviation estimates for continuous measures. Fully conditional specification imputation was acceptable for categorical measures. Results obtained through simulation reinforced and confirmed these findings. Practice Implications Significant investments are made in the collection of longitudinal data. The prudent handling of missing data can protect these investments and potentially improve the scientific information contained in pediatric longitudinal studies. PMID:28425202

  2. How to Make Our Models More Physically-based

    NASA Astrophysics Data System (ADS)

    Savenije, H. H. G.

    2016-12-01

    Models that are generally called "physically-based" unfortunately only have a partial view of the physical processes at play in hydrology. Although the coupled partial differential equations in these models reflect the water balance equations and the flow descriptors at laboratory scale, they miss essential characteristics of what determines the functioning of catchments. The most important active agent in catchments is the ecosystem (and sometimes people). What these agents do is manipulate the substrate in a way that it supports the essential functions of survival and productivity: infiltration of water, retention of moisture, mobilization and retention of nutrients, and drainage. Ecosystems do this in the most efficient way, in agreement with the landscape, and in response to climatic drivers. In brief, our hydrological system is alive and has a strong capacity to adjust to prevailing and changing circumstances. Although most physically based models take Newtonian theory at heart, as best they can, what they generally miss is Darwinian thinking on how an ecosystem evolves and adjusts its environment to maintain crucial hydrological functions. If this active agent is not reflected in our models, then they miss essential physics. Through a Darwinian approach, we can determine the root zone storage capacity of ecosystems, as a crucial component of hydrological models, determining the partitioning of fluxes and the conservation of moisture to bridge periods of drought. Another crucial element of physical systems is the evolution of drainage patterns, both on and below the surface. On the surface, such patterns facilitate infiltration or surface drainage with minimal erosion; in the unsaturated zone, patterns facilitate efficient replenishment of moisture deficits and preferential drainage when there is excess moisture; in the groundwater, patterns facilitate the efficient and gradual drainage of groundwater, resulting in linear reservoir recession. Models that do not incorporate these patterns are not physical. The parameters in the equations may be adjusted to compensate for the lake of patterns, but this involves scale-dependent calibration. In contrast to what is widely believed, relatively simple conceptual models can accommodate these physical processes accurately and very efficiently.

  3. Understanding repeated non-attendance in health services: a pilot analysis of administrative data and full study protocol for a national retrospective cohort.

    PubMed

    Williamson, Andrea E; Ellis, David A; Wilson, Philip; McQueenie, Ross; McConnachie, Alex

    2017-02-14

    Understanding the causes of low engagement in healthcare is a pre-requisite for improving health services' contribution to tackling health inequalities. Low engagement includes missing healthcare appointments. Serially (having a pattern of) missing general practice (GP) appointments may provide a risk marker for vulnerability and poorer health outcomes. A proof of concept pilot using GP appointment data and a focus group with GPs informed the development of missed appointment categories: patients can be classified based on the number of appointments missed each year. The full study, using a retrospective cohort design, will link routine health service and education data to determine the relationship between GP appointment attendance, health outcomes, healthcare usage, preventive health activity and social circumstances taking a life course approach and using data from the whole journey in the National Health Service (NHS) healthcare. 172 practices will be recruited (∼900 000 patients) across Scotland. The statistical analysis will focus on 2 key areas: factors that predict patients who serially miss appointments, and serial missed appointments as a predictor of future patient outcomes. Regression models will help understand how missed appointment patterns are associated with patient and practice characteristics. We shall identify key factors associated with serial missed appointments and potential interactions that might predict them. The results of the project will inform debates concerning how best to reduce non-attendance and increase patient engagement within healthcare systems. Significant non-academic beneficiaries include governments, policymakers and medical practitioners. Results will be disseminated via a combination of academic outputs (papers, conferences), social media and through collaborative public health/policy fora. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  4. A comparative survey of missed initial and follow-up appointments to psychiatric specialties in the United kingdom.

    PubMed

    Mitchell, Alex J; Selmes, Thomas

    2007-06-01

    Missed appointments are common in psychiatry. Nonattendance at the initial appointment may have different prognostic significance than nonattendance at subsequent appointments. This study examined the frequency of missed appointments among 9,511 initial outpatient appointments and 7,700 follow-up appointments across ten psychiatric subspecialties in a publicly funded mental health service in the United Kingdom. The pooled missed appointment rate was 15.9%, higher than in previous studies on primary and secondary care attendance in the United Kingdom. Nonattendance was lowest on Fridays, in winter months, and in geriatric psychiatry and highest for substance abuse services and in community psychiatry. In most services, attendance improved after the initial appointment, but in psychosomatic medicine and geriatric psychiatry this pattern was reversed. There was a low rate of missed appointments in geriatric psychiatry, rehabilitation psychiatry, cognitive-behavioral therapy, and psychosocial medicine. A high nonattendance rate was found among persons with drug and alcohol difficulties and to a lesser extent in general adult psychiatry. Future studies should consider initial and follow-up appointments as distinct.

  5. 29 CFR 4050.7 - Benefits of missing participants-in general.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 9 2014-07-01 2014-07-01 false Benefits of missing participants-in general. 4050.7 Section... TERMINATIONS MISSING PARTICIPANTS § 4050.7 Benefits of missing participants—in general. (a) If annuity purchased. If a plan administrator distributes a missing participant's benefit by purchasing an irrevocable...

  6. 29 CFR 4050.7 - Benefits of missing participants-in general.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 9 2011-07-01 2011-07-01 false Benefits of missing participants-in general. 4050.7 Section... TERMINATIONS MISSING PARTICIPANTS § 4050.7 Benefits of missing participants—in general. (a) If annuity purchased. If a plan administrator distributes a missing participant's benefit by purchasing an irrevocable...

  7. 29 CFR 4050.7 - Benefits of missing participants-in general.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 9 2010-07-01 2010-07-01 false Benefits of missing participants-in general. 4050.7 Section... TERMINATIONS MISSING PARTICIPANTS § 4050.7 Benefits of missing participants—in general. (a) If annuity purchased. If a plan administrator distributes a missing participant's benefit by purchasing an irrevocable...

  8. 29 CFR 4050.7 - Benefits of missing participants-in general.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 9 2013-07-01 2013-07-01 false Benefits of missing participants-in general. 4050.7 Section... TERMINATIONS MISSING PARTICIPANTS § 4050.7 Benefits of missing participants—in general. (a) If annuity purchased. If a plan administrator distributes a missing participant's benefit by purchasing an irrevocable...

  9. 29 CFR 4050.7 - Benefits of missing participants-in general.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 9 2012-07-01 2012-07-01 false Benefits of missing participants-in general. 4050.7 Section... TERMINATIONS MISSING PARTICIPANTS § 4050.7 Benefits of missing participants—in general. (a) If annuity purchased. If a plan administrator distributes a missing participant's benefit by purchasing an irrevocable...

  10. Growth Modeling with Non-Ignorable Dropout: Alternative Analyses of the STAR*D Antidepressant Trial

    PubMed Central

    Muthén, Bengt; Asparouhov, Tihomir; Hunter, Aimee; Leuchter, Andrew

    2011-01-01

    This paper uses a general latent variable framework to study a series of models for non-ignorable missingness due to dropout. Non-ignorable missing data modeling acknowledges that missingness may depend on not only covariates and observed outcomes at previous time points as with the standard missing at random (MAR) assumption, but also on latent variables such as values that would have been observed (missing outcomes), developmental trends (growth factors), and qualitatively different types of development (latent trajectory classes). These alternative predictors of missing data can be explored in a general latent variable framework using the Mplus program. A flexible new model uses an extended pattern-mixture approach where missingness is a function of latent dropout classes in combination with growth mixture modeling using latent trajectory classes. A new selection model allows not only an influence of the outcomes on missingness, but allows this influence to vary across latent trajectory classes. Recommendations are given for choosing models. The missing data models are applied to longitudinal data from STAR*D, the largest antidepressant clinical trial in the U.S. to date. Despite the importance of this trial, STAR*D growth model analyses using non-ignorable missing data techniques have not been explored until now. The STAR*D data are shown to feature distinct trajectory classes, including a low class corresponding to substantial improvement in depression, a minority class with a U-shaped curve corresponding to transient improvement, and a high class corresponding to no improvement. The analyses provide a new way to assess drug efficiency in the presence of dropout. PMID:21381817

  11. Hydrologic budget and conditions of Permian, Pennsylvanian, and Mississippian aquifers in the Appalachian Plateaus physiographic province

    USGS Publications Warehouse

    McCoy, Kurt J.; Yager, Richard M.; Nelms, David L.; Ladd, David E.; Monti,, Jack; Kozar, Mark D.

    2015-08-13

    A subset of 77 index streamgages, defined as having 60 or more years of complete record between the years 1930 and 2011 with no more than 20 percent missing data, was selected to show spatial patterns of change in the water budget. Data from the index streamgages showed that the overall trends in base flow are dependent upon the period of evaluation. Long-term (1930–2011) increases in base flow were observed throughout the study area. For two shorter periods (1930–1969 and 1970–2011) trends in base flow were largely negative. In general, spatial patterns of change in streamflow, base flow, and runoff were mixed but generally consistent with prevailing climate patterns and land-use changes.

  12. Meta-Analytic Methods of Pooling Correlation Matrices for Structural Equation Modeling under Different Patterns of Missing Data

    ERIC Educational Resources Information Center

    Furlow, Carolyn F.; Beretvas, S. Natasha

    2005-01-01

    Three methods of synthesizing correlations for meta-analytic structural equation modeling (SEM) under different degrees and mechanisms of missingness were compared for the estimation of correlation and SEM parameters and goodness-of-fit indices by using Monte Carlo simulation techniques. A revised generalized least squares (GLS) method for…

  13. Statistical approaches to account for missing values in accelerometer data: Applications to modeling physical activity.

    PubMed

    Yue Xu, Selene; Nelson, Sandahl; Kerr, Jacqueline; Godbole, Suneeta; Patterson, Ruth; Merchant, Gina; Abramson, Ian; Staudenmayer, John; Natarajan, Loki

    2018-04-01

    Physical inactivity is a recognized risk factor for many chronic diseases. Accelerometers are increasingly used as an objective means to measure daily physical activity. One challenge in using these devices is missing data due to device nonwear. We used a well-characterized cohort of 333 overweight postmenopausal breast cancer survivors to examine missing data patterns of accelerometer outputs over the day. Based on these observed missingness patterns, we created psuedo-simulated datasets with realistic missing data patterns. We developed statistical methods to design imputation and variance weighting algorithms to account for missing data effects when fitting regression models. Bias and precision of each method were evaluated and compared. Our results indicated that not accounting for missing data in the analysis yielded unstable estimates in the regression analysis. Incorporating variance weights and/or subject-level imputation improved precision by >50%, compared to ignoring missing data. We recommend that these simple easy-to-implement statistical tools be used to improve analysis of accelerometer data.

  14. Genetic Diversity Analysis of Highly Incomplete SNP Genotype Data with Imputations: An Empirical Assessment

    PubMed Central

    Fu, Yong-Bi

    2014-01-01

    Genotyping by sequencing (GBS) recently has emerged as a promising genomic approach for assessing genetic diversity on a genome-wide scale. However, concerns are not lacking about the uniquely large unbalance in GBS genotype data. Although some genotype imputation has been proposed to infer missing observations, little is known about the reliability of a genetic diversity analysis of GBS data, with up to 90% of observations missing. Here we performed an empirical assessment of accuracy in genetic diversity analysis of highly incomplete single nucleotide polymorphism genotypes with imputations. Three large single-nucleotide polymorphism genotype data sets for corn, wheat, and rice were acquired, and missing data with up to 90% of missing observations were randomly generated and then imputed for missing genotypes with three map-independent imputation methods. Estimating heterozygosity and inbreeding coefficient from original, missing, and imputed data revealed variable patterns of bias from assessed levels of missingness and genotype imputation, but the estimation biases were smaller for missing data without genotype imputation. The estimates of genetic differentiation were rather robust up to 90% of missing observations but became substantially biased when missing genotypes were imputed. The estimates of topology accuracy for four representative samples of interested groups generally were reduced with increased levels of missing genotypes. Probabilistic principal component analysis based imputation performed better in terms of topology accuracy than those analyses of missing data without genotype imputation. These findings are not only significant for understanding the reliability of the genetic diversity analysis with respect to large missing data and genotype imputation but also are instructive for performing a proper genetic diversity analysis of highly incomplete GBS or other genotype data. PMID:24626289

  15. Bias Characterization in Probabilistic Genotype Data and Improved Signal Detection with Multiple Imputation

    PubMed Central

    Palmer, Cameron; Pe’er, Itsik

    2016-01-01

    Missing data are an unavoidable component of modern statistical genetics. Different array or sequencing technologies cover different single nucleotide polymorphisms (SNPs), leading to a complicated mosaic pattern of missingness where both individual genotypes and entire SNPs are sporadically absent. Such missing data patterns cannot be ignored without introducing bias, yet cannot be inferred exclusively from nonmissing data. In genome-wide association studies, the accepted solution to missingness is to impute missing data using external reference haplotypes. The resulting probabilistic genotypes may be analyzed in the place of genotype calls. A general-purpose paradigm, called Multiple Imputation (MI), is known to model uncertainty in many contexts, yet it is not widely used in association studies. Here, we undertake a systematic evaluation of existing imputed data analysis methods and MI. We characterize biases related to uncertainty in association studies, and find that bias is introduced both at the imputation level, when imputation algorithms generate inconsistent genotype probabilities, and at the association level, when analysis methods inadequately model genotype uncertainty. We find that MI performs at least as well as existing methods or in some cases much better, and provides a straightforward paradigm for adapting existing genotype association methods to uncertain data. PMID:27310603

  16. Injury Characteristics of Low-Energy Lisfranc Injuries Compared With High-Energy Injuries.

    PubMed

    Renninger, Christopher H; Cochran, Grant; Tompane, Trevor; Bellamy, Joseph; Kuhn, Kevin

    2017-09-01

    Lisfranc injuries result from high- and low-energy mechanisms though the literature has been more focused on high-energy mechanisms. A comparison of high-energy (HE) and low-energy (LE) injury patterns is lacking. The objective of this study was to report injury patterns in LE Lisfranc joint injuries and compare them to HE injury patterns. Operative Lisfranc injuries were identified over a 5-year period. Patient demographics, mechanism of injury, injury pattern, associated injuries, missed diagnoses, clinical course, and imaging studies were reviewed and compared. HE mechanism was defined as motor vehicle crash, motorcycle crash, direct crush, and fall from greater than 4 feet and LE mechanism as athletic activity, ground level twisting, or fall from less than 4 feet. Thirty-two HE and 48 LE cases were identified with 19.3 months of average follow-up. There were no differences in demographics or missed diagnosis frequency (21% HE vs 18% LE). Time to seek care was not significantly different. HE injuries were more likely to have concomitant nonfoot fractures (37% vs 6%), concomitant foot fractures (78% vs 4%), cuboid fractures (31% vs 6%), metatarsal base fractures (84% vs 29%), displaced intra-articular fractures (59% vs 4%), and involvement of all 5 rays (23% vs 6%). LE injuries were more commonly ligamentous (68% vs 16%), with fewer rays involved (2.7 vs 4.1). LE mechanisms were a more common cause of Lisfranc joint injury in this cohort. These mechanisms generally resulted in an isolated, primarily ligamentous injury sparing the lateral column. Both types had high rates of missed injury that could result in delayed treatment. Differences in injury patterns could help direct future research to optimize treatment algorithms. Level III, comparative series.

  17. Pattern-Directed Attention in Uncertain Frequency Detection.

    DTIC Science & Technology

    1983-10-14

    performance when compared to a single frequency condition even if the listeners are aware that more than one signal can occur ( Creelman , 1960; Green...be missed. On the-other hand, the multiple band approach, introduced by Green (1958) and modified by Creelman (1960), assumes that listeners base...multiple-band approaches ( Creelman , 1960; Green, 1961; Macmillan & Schwartz, 1975). In general, the two views are difficult to distinguish empirically, and

  18. Toward a hybrid brain-computer interface based on repetitive visual stimuli with missing events.

    PubMed

    Wu, Yingying; Li, Man; Wang, Jing

    2016-07-26

    Steady-state visually evoked potentials (SSVEPs) can be elicited by repetitive stimuli and extracted in the frequency domain with satisfied performance. However, the temporal information of such stimulus is often ignored. In this study, we utilized repetitive visual stimuli with missing events to present a novel hybrid BCI paradigm based on SSVEP and omitted stimulus potential (OSP). Four discs flickering from black to white with missing flickers served as visual stimulators to simultaneously elicit subject's SSVEPs and OSPs. Key parameters in the new paradigm, including flicker frequency, optimal electrodes, missing flicker duration and intervals of missing events were qualitatively discussed with offline data. Two omitted flicker patterns including missing black/white disc were proposed and compared. Averaging times were optimized with Information Transfer Rate (ITR) in online experiments, where SSVEPs and OSPs were identified using Canonical Correlation Analysis in the frequency domain and Support Vector Machine (SVM)-Bayes fusion in the time domain, respectively. The online accuracy and ITR (mean ± standard deviation) over nine healthy subjects were 79.29 ± 18.14 % and 19.45 ± 11.99 bits/min with missing black disc pattern, and 86.82 ± 12.91 % and 24.06 ± 10.95 bits/min with missing white disc pattern, respectively. The proposed BCI paradigm, for the first time, demonstrated that SSVEPs and OSPs can be simultaneously elicited in single visual stimulus pattern and recognized in real-time with satisfied performance. Besides the frequency features such as SSVEP elicited by repetitive stimuli, we found a new feature (OSP) in the time domain to design a novel hybrid BCI paradigm by adding missing events in repetitive stimuli.

  19. A study on the mortality patterns of missing and deceased persons with dementia who died due to wandering.

    PubMed

    Kikuchi, Kazunori; Ijuin, Mutsuo; Awata, Shuichi; Suzuki, Takao

    2016-01-01

    To clarify the mortality patterns derived from differences in the causes of death and to subsequently promote search activity and prevent the death of missing persons. The Ministry of Health, Labour and Welfare (MHLW) performed a mail survey using a self-administered questionnaire. The families of all 388 deceased dementia patients from among all of the missing persons reports involving dementia patients that were submitted to the police in 2013, and the 10,322 missing persons with dementia (or suspected cases) were the subjects of this survey. The survey was conducted from January 5 to February 2 in 2015. We analyzed the data provided by the MHLW on 61 cases in which the cause of death was recorded; the factors that were related to the differences in the causes of death were examined using a chi-squared test (Fisher's direct method) and a residual analysis. Based on previous studies, we classified the causes of death into three categories: "drowning," "hypothermia," and "others (e.g., traumatic injury, disease progression)." When the cause of death was hypothermia, death often occurred between three to four days from the time that the deceased individual went missing. A significantly higher number of patients who died of other causes were found to have died on the day that they went missing. More than 40% of the drowning cases occurred on the day that the deceased individual went missing. We identified 3 patterns of mortality: (1) death on the day that the deceased individual went missing due to traumatic injury, disease progression, drowning, and other causes; (2) death due to hypothermia within a few days after the deceased individual went missing; and (3) patterns other than (1) and (2).

  20. Sample size considerations for paired experimental design with incomplete observations of continuous outcomes.

    PubMed

    Zhu, Hong; Xu, Xiaohan; Ahn, Chul

    2017-01-01

    Paired experimental design is widely used in clinical and health behavioral studies, where each study unit contributes a pair of observations. Investigators often encounter incomplete observations of paired outcomes in the data collected. Some study units contribute complete pairs of observations, while the others contribute either pre- or post-intervention observations. Statistical inference for paired experimental design with incomplete observations of continuous outcomes has been extensively studied in literature. However, sample size method for such study design is sparsely available. We derive a closed-form sample size formula based on the generalized estimating equation approach by treating the incomplete observations as missing data in a linear model. The proposed method properly accounts for the impact of mixed structure of observed data: a combination of paired and unpaired outcomes. The sample size formula is flexible to accommodate different missing patterns, magnitude of missingness, and correlation parameter values. We demonstrate that under complete observations, the proposed generalized estimating equation sample size estimate is the same as that based on the paired t-test. In the presence of missing data, the proposed method would lead to a more accurate sample size estimate comparing with the crude adjustment. Simulation studies are conducted to evaluate the finite-sample performance of the generalized estimating equation sample size formula. A real application example is presented for illustration.

  1. Comparability of item quality indices from sparse data matrices with random and non-random missing data patterns.

    PubMed

    Wolfe, Edward W; McGill, Michael T

    2011-01-01

    This article summarizes a simulation study of the performance of five item quality indicators (the weighted and unweighted versions of the mean square and standardized mean square fit indices and the point-measure correlation) under conditions of relatively high and low amounts of missing data under both random and conditional patterns of missing data for testing contexts such as those encountered in operational administrations of a computerized adaptive certification or licensure examination. The results suggest that weighted fit indices, particularly the standardized mean square index, and the point-measure correlation provide the most consistent information between random and conditional missing data patterns and that these indices perform more comparably for items near the passing score than for items with extreme difficulty values.

  2. Influence of Pattern of Missing Data on Performance of Imputation Methods: An Example Using National Data on Drug Injection in Prisons

    PubMed Central

    Haji-Maghsoudi, Saiedeh; Haghdoost, Ali-akbar; Rastegari, Azam; Baneshi, Mohammad Reza

    2013-01-01

    Background: Policy makers need models to be able to detect groups at high risk of HIV infection. Incomplete records and dirty data are frequently seen in national data sets. Presence of missing data challenges the practice of model development. Several studies suggested that performance of imputation methods is acceptable when missing rate is moderate. One of the issues which was of less concern, to be addressed here, is the role of the pattern of missing data. Methods: We used information of 2720 prisoners. Results derived from fitting regression model to whole data were served as gold standard. Missing data were then generated so that 10%, 20% and 50% of data were lost. In scenario 1, we generated missing values, at above rates, in one variable which was significant in gold model (age). In scenario 2, a small proportion of each of independent variable was dropped out. Four imputation methods, under different Event Per Variable (EPV) values, were compared in terms of selection of important variables and parameter estimation. Results: In scenario 2, bias in estimates was low and performances of all methods for handing missing data were similar. All methods at all missing rates were able to detect significance of age. In scenario 1, biases in estimations were increased, in particular at 50% missing rate. Here at EPVs of 10 and 5, imputation methods failed to capture effect of age. Conclusion: In scenario 2, all imputation methods at all missing rates, were able to detect age as being significant. This was not the case in scenario 1. Our results showed that performance of imputation methods depends on the pattern of missing data. PMID:24596839

  3. Multiple imputation for assessment of exposures to drinking water contaminants: evaluation with the Atrazine Monitoring Program.

    PubMed

    Jones, Rachael M; Stayner, Leslie T; Demirtas, Hakan

    2014-10-01

    Drinking water may contain pollutants that harm human health. The frequency of pollutant monitoring may occur quarterly, annually, or less frequently, depending upon the pollutant, the pollutant concentration, and community water system. However, birth and other health outcomes are associated with narrow time-windows of exposure. Infrequent monitoring impedes linkage between water quality and health outcomes for epidemiological analyses. To evaluate the performance of multiple imputation to fill in water quality values between measurements in community water systems (CWSs). The multiple imputation method was implemented in a simulated setting using data from the Atrazine Monitoring Program (AMP, 2006-2009 in five Midwestern states). Values were deleted from the AMP data to leave one measurement per month. Four patterns reflecting drinking water monitoring regulations were used to delete months of data in each CWS: three patterns were missing at random and one pattern was missing not at random. Synthetic health outcome data were created using a linear and a Poisson exposure-response relationship with five levels of hypothesized association, respectively. The multiple imputation method was evaluated by comparing the exposure-response relationships estimated based on multiply imputed data with the hypothesized association. The four patterns deleted 65-92% months of atrazine observations in AMP data. Even with these high rates of missing information, our procedure was able to recover most of the missing information when the synthetic health outcome was included for missing at random patterns and for missing not at random patterns with low-to-moderate exposure-response relationships. Multiple imputation appears to be an effective method for filling in water quality values between measurements. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Effects of mindfulness meditation on occupational functioning and health care utilization in individuals with anxiety.

    PubMed

    Hoge, Elizabeth A; Guidos, Brittany M; Mete, Mihriye; Bui, Eric; Pollack, Mark H; Simon, Naomi M; Dutton, Mary Ann

    2017-04-01

    To examine the effect of mindfulness meditation on occupational functioning in individuals with Generalized anxiety disorder (GAD). Fifty-seven individuals with GAD (mean (SD) age=39 (13); 56% women) participated in an 8-week clinical trial in which they were randomized to mindfulness-based stress reduction (MBSR) or an attention control class. In this secondary analysis, absenteeism, entire workdays missed, partial workdays missed, and healthcare utilization patterns were assessed before and after treatment. Compared to the attention control class, participation in MBSR was associated with a significantly greater decrease in partial work days missed for adults with GAD (t=2.734, df=51, p=0.009). Interestingly, a dose effect was observed during the 24-week post-treatment follow-up period: among MBSR participants, greater home mindfulness meditation practice was associated with less work loss and with fewer mental health professional visits. Mindfulness meditation training may improve occupational functioning and decrease healthcare utilization in adults with GAD. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. A Probability Based Framework for Testing the Missing Data Mechanism

    ERIC Educational Resources Information Center

    Lin, Johnny Cheng-Han

    2013-01-01

    Many methods exist for imputing missing data but fewer methods have been proposed to test the missing data mechanism. Little (1988) introduced a multivariate chi-square test for the missing completely at random data mechanism (MCAR) that compares observed means for each pattern with expectation-maximization (EM) estimated means. As an alternative,…

  6. Injury patterns and injury rates in the circus arts: an analysis of 5 years of data from Cirque du Soleil.

    PubMed

    Shrier, Ian; Meeuwisse, Willem H; Matheson, Gordon O; Wingfield, Kristin; Steele, Russell J; Prince, François; Hanley, James; Montanaro, Michael

    2009-06-01

    Human circus arts are gaining increasing popularity as a physical activity with more than 500 companies and 200 schools. The only injury data that currently exist are a few case reports and 1 survey. To describe injury patterns and injury rates among Cirque du Soleil artists between 2002 and 2006. Descriptive epidemiology study. The authors defined an injury as any work-related condition recorded in an electronic injury database that required a visit to the show therapist. Analyses for treatments, missed performances, and injury rates (per 1000 artist performances) were based on a subset of data that contained appropriate denominator (exposure) information (began in 2004). There were 1376 artists who sustained a total of the 18 336 show- or training-related injuries. The pattern of injuries was generally similar across sex and performance versus training. Most injuries were minor. Of the 6701 injuries with exposure data, 80% required < or =7 treatments and resulted in < or =1 completely missed performance. The overall show injury rate was 9.7 (95% confidence interval, 9.4-10.0; for context, published National Collegiate Athletic Association women's gymnastics rate was 15.2 injuries per 1000 athlete-exposures). The rate for injuries resulting in more than 15 missed performances for acrobats (highest risk group) was 0.74 (95% confidence interval, 0.65-0.83), which is much lower than the corresponding estimated National Collegiate Athletic Association women's gymnastics rate. Most injuries in circus performers are minor, and rates of more serious injuries are lower than for many National Collegiate Athletic Association sports.

  7. Randomly and Non-Randomly Missing Renal Function Data in the Strong Heart Study: A Comparison of Imputation Methods

    PubMed Central

    Shara, Nawar; Yassin, Sayf A.; Valaitis, Eduardas; Wang, Hong; Howard, Barbara V.; Wang, Wenyu; Lee, Elisa T.; Umans, Jason G.

    2015-01-01

    Kidney and cardiovascular disease are widespread among populations with high prevalence of diabetes, such as American Indians participating in the Strong Heart Study (SHS). Studying these conditions simultaneously in longitudinal studies is challenging, because the morbidity and mortality associated with these diseases result in missing data, and these data are likely not missing at random. When such data are merely excluded, study findings may be compromised. In this article, a subset of 2264 participants with complete renal function data from Strong Heart Exams 1 (1989–1991), 2 (1993–1995), and 3 (1998–1999) was used to examine the performance of five methods used to impute missing data: listwise deletion, mean of serial measures, adjacent value, multiple imputation, and pattern-mixture. Three missing at random models and one non-missing at random model were used to compare the performance of the imputation techniques on randomly and non-randomly missing data. The pattern-mixture method was found to perform best for imputing renal function data that were not missing at random. Determining whether data are missing at random or not can help in choosing the imputation method that will provide the most accurate results. PMID:26414328

  8. Randomly and Non-Randomly Missing Renal Function Data in the Strong Heart Study: A Comparison of Imputation Methods.

    PubMed

    Shara, Nawar; Yassin, Sayf A; Valaitis, Eduardas; Wang, Hong; Howard, Barbara V; Wang, Wenyu; Lee, Elisa T; Umans, Jason G

    2015-01-01

    Kidney and cardiovascular disease are widespread among populations with high prevalence of diabetes, such as American Indians participating in the Strong Heart Study (SHS). Studying these conditions simultaneously in longitudinal studies is challenging, because the morbidity and mortality associated with these diseases result in missing data, and these data are likely not missing at random. When such data are merely excluded, study findings may be compromised. In this article, a subset of 2264 participants with complete renal function data from Strong Heart Exams 1 (1989-1991), 2 (1993-1995), and 3 (1998-1999) was used to examine the performance of five methods used to impute missing data: listwise deletion, mean of serial measures, adjacent value, multiple imputation, and pattern-mixture. Three missing at random models and one non-missing at random model were used to compare the performance of the imputation techniques on randomly and non-randomly missing data. The pattern-mixture method was found to perform best for imputing renal function data that were not missing at random. Determining whether data are missing at random or not can help in choosing the imputation method that will provide the most accurate results.

  9. The Impact of Five Missing Data Treatments on a Cross-Classified Random Effects Model

    ERIC Educational Resources Information Center

    Hoelzle, Braden R.

    2012-01-01

    The present study compared the performance of five missing data treatment methods within a Cross-Classified Random Effects Model environment under various levels and patterns of missing data given a specified sample size. Prior research has shown the varying effect of missing data treatment options within the context of numerous statistical…

  10. Simple descriptive missing data indicators in longitudinal studies with attrition, intermittent missing data and a high number of follow-ups.

    PubMed

    Wærsted, Morten; Børnick, Taran Svenssen; Twisk, Jos W R; Veiersted, Kaj Bo

    2018-02-13

    Missing data in longitudinal studies may constitute a source of bias. We suggest three simple missing data indicators for the initial phase of getting an overview of the missingness pattern in a dataset with a high number of follow-ups. Possible use of the indicators is exemplified in two datasets allowing wave nonresponse; a Norwegian dataset of 420 subjects examined at 21 occasions during 6.5 years and a Dutch dataset of 350 subjects with ten repeated measurements over a period of 35 years. The indicators Last response (the timing of last response), Retention (the number of responded follow-ups), and Dispersion (the evenness of the distribution of responses) are introduced. The proposed indicators reveal different aspects of the missing data pattern, and may give the researcher a better insight into the pattern of missingness in a study with several follow-ups, as a starting point for analyzing possible bias. Although the indicators are positively correlated to each other, potential predictors of missingness can have a different relationship with different indicators leading to a better understanding of the missing data mechanism in longitudinal studies. These indictors may be useful descriptive tools when starting to look into a longitudinal dataset with many follow-ups.

  11. Selection-Fusion Approach for Classification of Datasets with Missing Values

    PubMed Central

    Ghannad-Rezaie, Mostafa; Soltanian-Zadeh, Hamid; Ying, Hao; Dong, Ming

    2010-01-01

    This paper proposes a new approach based on missing value pattern discovery for classifying incomplete data. This approach is particularly designed for classification of datasets with a small number of samples and a high percentage of missing values where available missing value treatment approaches do not usually work well. Based on the pattern of the missing values, the proposed approach finds subsets of samples for which most of the features are available and trains a classifier for each subset. Then, it combines the outputs of the classifiers. Subset selection is translated into a clustering problem, allowing derivation of a mathematical framework for it. A trade off is established between the computational complexity (number of subsets) and the accuracy of the overall classifier. To deal with this trade off, a numerical criterion is proposed for the prediction of the overall performance. The proposed method is applied to seven datasets from the popular University of California, Irvine data mining archive and an epilepsy dataset from Henry Ford Hospital, Detroit, Michigan (total of eight datasets). Experimental results show that classification accuracy of the proposed method is superior to those of the widely used multiple imputations method and four other methods. They also show that the level of superiority depends on the pattern and percentage of missing values. PMID:20212921

  12. Finding the missing stimulus mismatch negativity (MMN): Emitted MMN to violations of an auditory gestalt

    PubMed Central

    Salisbury, Dean F

    2011-01-01

    Deviations from repetitive auditory stimuli evoke a mismatch negativity (MMN). Counter-intuitively, omissions of repetitive stimuli do not. Violations of patterns reflecting complex rules also evoke MMN. To detect a MMN to missing stimuli, we developed an auditory gestalt task using one stimulus. Groups of 6 pips (50 msec duration, 330 msec stimulus onset asynchrony (SOA), 400 trials), were presented with an inter-trial interval (ITI) of 750 msec while subjects (n=16) watched a silent video. Occasional deviant groups had missing 4th or 6th tones (50 trials each). Missing stimuli evoked a MMN (p<.05). The missing 4th (−0.8 uV, p <.01) and the missing 6th stimuli (−1.1 uV, p <.05) were more negative than standard 6th stimuli (0.3 uV). MMN can be elicited by a missing stimulus at long SOAs by violation of a gestalt grouping rule. Homogenous stimulus streams appear to differ in the relative weighting of omissions than strongly patterned streams. PMID:22221004

  13. Multiple imputation by chained equations for systematically and sporadically missing multilevel data.

    PubMed

    Resche-Rigon, Matthieu; White, Ian R

    2018-06-01

    In multilevel settings such as individual participant data meta-analysis, a variable is 'systematically missing' if it is wholly missing in some clusters and 'sporadically missing' if it is partly missing in some clusters. Previously proposed methods to impute incomplete multilevel data handle either systematically or sporadically missing data, but frequently both patterns are observed. We describe a new multiple imputation by chained equations (MICE) algorithm for multilevel data with arbitrary patterns of systematically and sporadically missing variables. The algorithm is described for multilevel normal data but can easily be extended for other variable types. We first propose two methods for imputing a single incomplete variable: an extension of an existing method and a new two-stage method which conveniently allows for heteroscedastic data. We then discuss the difficulties of imputing missing values in several variables in multilevel data using MICE, and show that even the simplest joint multilevel model implies conditional models which involve cluster means and heteroscedasticity. However, a simulation study finds that the proposed methods can be successfully combined in a multilevel MICE procedure, even when cluster means are not included in the imputation models.

  14. Multiple imputation to deal with missing EQ-5D-3L data: Should we impute individual domains or the actual index?

    PubMed

    Simons, Claire L; Rivero-Arias, Oliver; Yu, Ly-Mee; Simon, Judit

    2015-04-01

    Missing data are a well-known and widely documented problem in cost-effectiveness analyses alongside clinical trials using individual patient-level data. Current methodological research recommends multiple imputation (MI) to deal with missing health outcome data, but there is little guidance on whether MI for multi-attribute questionnaires, such as the EQ-5D-3L, should be carried out at domain or at summary score level. In this paper, we evaluated the impact of imputing individual domains versus imputing index values to deal with missing EQ-5D-3L data using a simulation study and developed recommendations for future practice. We simulated missing data in a patient-level dataset with complete EQ-5D-3L data at one point in time from a large multinational clinical trial (n = 1,814). Different proportions of missing data were generated using a missing at random (MAR) mechanism and three different scenarios were studied. The performance of using each method was evaluated using root mean squared error and mean absolute error of the actual versus predicted EQ-5D-3L indices. In large sample sizes (n > 500) and a missing data pattern that follows mainly unit non-response, imputing domains or the index produced similar results. However, domain imputation became more accurate than index imputation with pattern of missingness following an item non-response. For smaller sample sizes (n < 100), index imputation was more accurate. When MI models were misspecified, both domain and index imputations were inaccurate for any proportion of missing data. The decision between imputing the domains or the EQ-5D-3L index scores depends on the observed missing data pattern and the sample size available for analysis. Analysts conducting this type of exercises should also evaluate the sensitivity of the analysis to the MAR assumption and whether the imputation model is correctly specified.

  15. How to deal with missing longitudinal data in cost of illness analysis in Alzheimer's disease-suggestions from the GERAS observational study.

    PubMed

    Belger, Mark; Haro, Josep Maria; Reed, Catherine; Happich, Michael; Kahle-Wrobleski, Kristin; Argimon, Josep Maria; Bruno, Giuseppe; Dodel, Richard; Jones, Roy W; Vellas, Bruno; Wimo, Anders

    2016-07-18

    Missing data are a common problem in prospective studies with a long follow-up, and the volume, pattern and reasons for missing data may be relevant when estimating the cost of illness. We aimed to evaluate the effects of different methods for dealing with missing longitudinal cost data and for costing caregiver time on total societal costs in Alzheimer's disease (AD). GERAS is an 18-month observational study of costs associated with AD. Total societal costs included patient health and social care costs, and caregiver health and informal care costs. Missing data were classified as missing completely at random (MCAR), missing at random (MAR) or missing not at random (MNAR). Simulation datasets were generated from baseline data with 10-40 % missing total cost data for each missing data mechanism. Datasets were also simulated to reflect the missing cost data pattern at 18 months using MAR and MNAR assumptions. Naïve and multiple imputation (MI) methods were applied to each dataset and results compared with complete GERAS 18-month cost data. Opportunity and replacement cost approaches were used for caregiver time, which was costed with and without supervision included and with time for working caregivers only being costed. Total costs were available for 99.4 % of 1497 patients at baseline. For MCAR datasets, naïve methods performed as well as MI methods. For MAR, MI methods performed better than naïve methods. All imputation approaches were poor for MNAR data. For all approaches, percentage bias increased with missing data volume. For datasets reflecting 18-month patterns, a combination of imputation methods provided more accurate cost estimates (e.g. bias: -1 % vs -6 % for single MI method), although different approaches to costing caregiver time had a greater impact on estimated costs (29-43 % increase over base case estimate). Methods used to impute missing cost data in AD will impact on accuracy of cost estimates although varying approaches to costing informal caregiver time has the greatest impact on total costs. Tailoring imputation methods to the reason for missing data will further our understanding of the best analytical approach for studies involving cost outcomes.

  16. 40 CFR 75.30 - General provisions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) CONTINUOUS EMISSION MONITORING Missing Data Substitution Procedures § 75.30 General provisions. (a) Except as... continuous emission monitoring system according to the missing data procedures in this subpart whenever the... missing data procedures in this subpart if the owner or operator uses SO2, CO2, NOX, or O2 concentration...

  17. 40 CFR 75.30 - General provisions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) CONTINUOUS EMISSION MONITORING Missing Data Substitution Procedures § 75.30 General provisions. (a) Except as... continuous emission monitoring system according to the missing data procedures in this subpart whenever the... missing data procedures in this subpart if the owner or operator uses SO2, CO2, NOX, or O2 concentration...

  18. 40 CFR 75.30 - General provisions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) CONTINUOUS EMISSION MONITORING Missing Data Substitution Procedures § 75.30 General provisions. (a) Except as... continuous emission monitoring system according to the missing data procedures in this subpart whenever the... missing data procedures in this subpart if the owner or operator uses SO2, CO2, NOX, or O2 concentration...

  19. 40 CFR 75.30 - General provisions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) CONTINUOUS EMISSION MONITORING Missing Data Substitution Procedures § 75.30 General provisions. (a) Except as... continuous emission monitoring system according to the missing data procedures in this subpart whenever the... missing data procedures in this subpart if the owner or operator uses SO2, CO2, NOX, or O2 concentration...

  20. 40 CFR 75.30 - General provisions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) CONTINUOUS EMISSION MONITORING Missing Data Substitution Procedures § 75.30 General provisions. (a) Except as... continuous emission monitoring system according to the missing data procedures in this subpart whenever the... missing data procedures in this subpart if the owner or operator uses SO2, CO2, NOX, or O2 concentration...

  1. Bayesian sensitivity analysis methods to evaluate bias due to misclassification and missing data using informative priors and external validation data.

    PubMed

    Luta, George; Ford, Melissa B; Bondy, Melissa; Shields, Peter G; Stamey, James D

    2013-04-01

    Recent research suggests that the Bayesian paradigm may be useful for modeling biases in epidemiological studies, such as those due to misclassification and missing data. We used Bayesian methods to perform sensitivity analyses for assessing the robustness of study findings to the potential effect of these two important sources of bias. We used data from a study of the joint associations of radiotherapy and smoking with primary lung cancer among breast cancer survivors. We used Bayesian methods to provide an operational way to combine both validation data and expert opinion to account for misclassification of the two risk factors and missing data. For comparative purposes we considered a "full model" that allowed for both misclassification and missing data, along with alternative models that considered only misclassification or missing data, and the naïve model that ignored both sources of bias. We identified noticeable differences between the four models with respect to the posterior distributions of the odds ratios that described the joint associations of radiotherapy and smoking with primary lung cancer. Despite those differences we found that the general conclusions regarding the pattern of associations were the same regardless of the model used. Overall our results indicate a nonsignificantly decreased lung cancer risk due to radiotherapy among nonsmokers, and a mildly increased risk among smokers. We described easy to implement Bayesian methods to perform sensitivity analyses for assessing the robustness of study findings to misclassification and missing data. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Nonparametric Multiple Imputation for Questionnaires with Individual Skip Patterns and Constraints: The Case of Income Imputation in The National Educational Panel Study

    ERIC Educational Resources Information Center

    Aßmann, Christian; Würbach, Ariane; Goßmann, Solange; Geissler, Ferdinand; Bela, Anika

    2017-01-01

    Large-scale surveys typically exhibit data structures characterized by rich mutual dependencies between surveyed variables and individual-specific skip patterns. Despite high efforts in fieldwork and questionnaire design, missing values inevitably occur. One approach for handling missing values is to provide multiply imputed data sets, thus…

  3. Development of an online morbidity, mortality, and near-miss reporting system to identify patterns of adverse events in surgical patients.

    PubMed

    Bilimoria, Karl Y; Kmiecik, Thomas E; DaRosa, Debra A; Halverson, Amy; Eskandari, Mark K; Bell, Richard H; Soper, Nathaniel J; Wayne, Jeffrey D

    2009-04-01

    To design a Web-based system to track adverse and near-miss events, to establish an automated method to identify patterns of events, and to assess the adverse event reporting behavior of physicians. A Web-based system was designed to collect physician-reported adverse events including weekly Morbidity and Mortality (M&M) entries and anonymous adverse/near-miss events. An automated system was set up to help identify event patterns. Adverse event frequency was compared with hospital databases to assess reporting completeness. A metropolitan tertiary care center. Identification of adverse event patterns and completeness of reporting. From September 2005 to August 2007, 15,524 surgical patients were reported including 957 (6.2%) adverse events and 34 (0.2%) anonymous reports. The automated pattern recognition system helped identify 4 event patterns from M&M reports and 3 patterns from anonymous/near-miss reporting. After multidisciplinary meetings and expert reviews, the patterns were addressed with educational initiatives, correction of systems issues, and/or intensive quality monitoring. Only 25% of complications and 42% of inpatient deaths were reported. A total of 75.2% of adverse events resulting in permanent disability or death were attributed to the nature of the disease. Interventions to improve reporting were largely unsuccessful. We have developed a user-friendly Web-based system to track complications and identify patterns of adverse events. Underreporting of adverse events and attributing the complication to the nature of the disease represent a problem in reporting culture among surgeons at our institution. Similar systems should be used by surgery departments, particularly those affiliated with teaching hospitals, to identify quality improvement opportunities.

  4. 19 CFR 201.3a - Missing children information.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 19 Customs Duties 3 2010-04-01 2010-04-01 false Missing children information. 201.3a Section 201.3a Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION GENERAL RULES OF GENERAL APPLICATION Miscellaneous § 201.3a Missing children information. (a) Pursuant to 39 U.S.C. 3220, penalty mail sent by the...

  5. 19 CFR 201.3a - Missing children information.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 19 Customs Duties 3 2013-04-01 2013-04-01 false Missing children information. 201.3a Section 201.3a Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION GENERAL RULES OF GENERAL APPLICATION Miscellaneous § 201.3a Missing children information. (a) Pursuant to 39 U.S.C. 3220, penalty mail sent by the...

  6. 19 CFR 201.3a - Missing children information.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 19 Customs Duties 3 2014-04-01 2014-04-01 false Missing children information. 201.3a Section 201.3a Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION GENERAL RULES OF GENERAL APPLICATION Miscellaneous § 201.3a Missing children information. (a) Pursuant to 39 U.S.C. 3220, penalty mail sent by the...

  7. 19 CFR 201.3a - Missing children information.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 19 Customs Duties 3 2012-04-01 2012-04-01 false Missing children information. 201.3a Section 201.3a Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION GENERAL RULES OF GENERAL APPLICATION Miscellaneous § 201.3a Missing children information. (a) Pursuant to 39 U.S.C. 3220, penalty mail sent by the...

  8. 19 CFR 201.3a - Missing children information.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 19 Customs Duties 3 2011-04-01 2011-04-01 false Missing children information. 201.3a Section 201.3a Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION GENERAL RULES OF GENERAL APPLICATION Miscellaneous § 201.3a Missing children information. (a) Pursuant to 39 U.S.C. 3220, penalty mail sent by the...

  9. Method variation in the impact of missing data on response shift detection.

    PubMed

    Schwartz, Carolyn E; Sajobi, Tolulope T; Verdam, Mathilde G E; Sebille, Veronique; Lix, Lisa M; Guilleux, Alice; Sprangers, Mirjam A G

    2015-03-01

    Missing data due to attrition or item non-response can result in biased estimates and loss of power in longitudinal quality-of-life (QOL) research. The impact of missing data on response shift (RS) detection is relatively unknown. This overview article synthesizes the findings of three methods tested in this special section regarding the impact of missing data patterns on RS detection in incomplete longitudinal data. The RS detection methods investigated include: (1) Relative importance analysis to detect reprioritization RS in stroke caregivers; (2) Oort's structural equation modeling (SEM) to detect recalibration, reprioritization, and reconceptualization RS in cancer patients; and (3) Rasch-based item-response theory-based (IRT) models as compared to SEM models to detect recalibration and reprioritization RS in hospitalized chronic disease patients. Each method dealt with missing data differently, either with imputation (1), attrition-based multi-group analysis (2), or probabilistic analysis that is robust to missingness due to the specific objectivity property (3). Relative importance analyses were sensitive to the type and amount of missing data and imputation method, with multiple imputation showing the largest RS effects. The attrition-based multi-group SEM revealed differential effects of both the changes in health-related QOL and the occurrence of response shift by attrition stratum, and enabled a more complete interpretation of findings. The IRT RS algorithm found evidence of small recalibration and reprioritization effects in General Health, whereas SEM mostly evidenced small recalibration effects. These differences may be due to differences between the two methods in handling of missing data. Missing data imputation techniques result in different conclusions about the presence of reprioritization RS using the relative importance method, while the attrition-based SEM approach highlighted different recalibration and reprioritization RS effects by attrition group. The IRT analyses detected more recalibration and reprioritization RS effects than SEM, presumably due to IRT's robustness to missing data. Future research should apply simulation techniques in order to make conclusive statements about the impacts of missing data according to the type and amount of RS.

  10. 38 CFR 1.705 - Restrictions on use of missing children information.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... missing children information. 1.705 Section 1.705 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS GENERAL PROVISIONS Use of Official Mail in the Location and Recovery of Missing Children § 1.705 Restrictions on use of missing children information. Missing children pictures and...

  11. 38 CFR 1.705 - Restrictions on use of missing children information.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... missing children information. 1.705 Section 1.705 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS GENERAL PROVISIONS Use of Official Mail in the Location and Recovery of Missing Children § 1.705 Restrictions on use of missing children information. Missing children pictures and...

  12. 38 CFR 1.705 - Restrictions on use of missing children information.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... missing children information. 1.705 Section 1.705 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS GENERAL PROVISIONS Use of Official Mail in the Location and Recovery of Missing Children § 1.705 Restrictions on use of missing children information. Missing children pictures and...

  13. 38 CFR 1.705 - Restrictions on use of missing children information.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... missing children information. 1.705 Section 1.705 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS GENERAL PROVISIONS Use of Official Mail in the Location and Recovery of Missing Children § 1.705 Restrictions on use of missing children information. Missing children pictures and...

  14. 38 CFR 1.705 - Restrictions on use of missing children information.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... missing children information. 1.705 Section 1.705 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS GENERAL PROVISIONS Use of Official Mail in the Location and Recovery of Missing Children § 1.705 Restrictions on use of missing children information. Missing children pictures and...

  15. Modeling Nonignorable Missing Data in Speeded Tests

    ERIC Educational Resources Information Center

    Glas, Cees A. W.; Pimentel, Jonald L.

    2008-01-01

    In tests with time limits, items at the end are often not reached. Usually, the pattern of missing responses depends on the ability level of the respondents; therefore, missing data are not ignorable in statistical inference. This study models data using a combination of two item response theory (IRT) models: one for the observed response data and…

  16. I've changed, but I'm not less happy: Interview study among nonclinical relatives of long-term missing persons.

    PubMed

    Lenferink, Lonneke I M; de Keijser, Jos; Piersma, Eline; Boelen, Paul A

    2018-07-01

    Twenty-three nonclinical relatives of long-term missing persons were interviewed. Patterns of functioning over time were studied retrospectively by instructing participants to draw a graph that best described their pattern. Patterns most frequently drawn were a recovery and resilient/stable pattern. Participants were also asked to select 5 out of 15 cards referring to coping strategies, which they considered most helpful in dealing with the disappearance. Acceptance, emotional social support, mental disengagement, and venting emotions were most frequently chosen. This study provided some indication of coping strategies that could be strengthened in treatment for those in need of support.

  17. Age and correlation of the Calera Limestone in the Permanente terrane of northern California

    USGS Publications Warehouse

    Sliter, William V.; McGann, Mary

    1992-01-01

    Planktonic foraminifers indicate that outcrops of Calera Limestone from the Permanente terrane in the Franciscan Complex of northern California range in age from possibly as old as Barremian to late Turonian. Underlying black limestone, which is devoid of planktonic foraminifers, presumably is Barremian in age or older. The top of the sequence exposed in major quarries is always faulted. Improved biostratigraphic resolution shows two patterns of missing time intervals. The primary pattern, which is found at all localities and involves missing planktonic foraminiferal zones in the late Aptian to early Albian and the late Albian, is linked to paleoceanographic changes in the Cretaceous Pacific Ocean. The secondary pattern, which is found at the scattered outcrops outside the major quarries and involves missing zones in the Albian and Cenomanian, suggests the results of a common tectonic history related to the accretion of a large seamount.

  18. Missing value imputation: with application to handwriting data

    NASA Astrophysics Data System (ADS)

    Xu, Zhen; Srihari, Sargur N.

    2015-01-01

    Missing values make pattern analysis difficult, particularly with limited available data. In longitudinal research, missing values accumulate, thereby aggravating the problem. Here we consider how to deal with temporal data with missing values in handwriting analysis. In the task of studying development of individuality of handwriting, we encountered the fact that feature values are missing for several individuals at several time instances. Six algorithms, i.e., random imputation, mean imputation, most likely independent value imputation, and three methods based on Bayesian network (static Bayesian network, parameter EM, and structural EM), are compared with children's handwriting data. We evaluate the accuracy and robustness of the algorithms under different ratios of missing data and missing values, and useful conclusions are given. Specifically, static Bayesian network is used for our data which contain around 5% missing data to provide adequate accuracy and low computational cost.

  19. Use of handheld sonar to locate a missing diver.

    PubMed

    McGrane, Owen; Cronin, Aaron; Hile, David

    2013-03-01

    The purpose of this study was to investigate whether a handheld sonar device significantly reduces the mean time needed to locate a missing diver. This institutional review board approved, prospective, crossover study used a voluntary convenience sample of 10 scuba divers. Participants conducted both a standard and modified search to locate a simulated missing diver. The standard search utilized a conventional search pattern starting at the point where the missing diver (simulated) was last seen. The modified search used a sonar beacon to augment the search. For each search method, successful completion of the search was defined as locating the missing diver within 40 minutes. Twenty total dives were completed. Using a standard search pattern, the missing diver was found by only 1 diver (10%), taking 18 minutes and 45 seconds. In the sonar-assisted search group, the missing diver was found by all 10 participants (100%), taking an average of 2 minutes and 47 seconds (SD 1 minute, 20 seconds). Using the nonparametric related samples Wilcoxon signed rank test, actual times between the sonar group and the standard group were significant (P < .01). Using paired samples t tests, the sonar group's self-assessed confidence increased significantly after using the sonar (P < .001), whereas the standard group decreased in confidence (not statistically significant, P = .111). Handheld sonar significantly reduces the mean duration to locate a missing diver as well as increasing users' confidence in their ability to find a missing diver when compared with standard search techniques. Copyright © 2013 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.

  20. Modeling missing data in knowledge space theory.

    PubMed

    de Chiusole, Debora; Stefanutti, Luca; Anselmi, Pasquale; Robusto, Egidio

    2015-12-01

    Missing data are a well known issue in statistical inference, because some responses may be missing, even when data are collected carefully. The problem that arises in these cases is how to deal with missing data. In this article, the missingness is analyzed in knowledge space theory, and in particular when the basic local independence model (BLIM) is applied to the data. Two extensions of the BLIM to missing data are proposed: The former, called ignorable missing BLIM (IMBLIM), assumes that missing data are missing completely at random; the latter, called missing BLIM (MissBLIM), introduces specific dependencies of the missing data on the knowledge states, thus assuming that the missing data are missing not at random. The IMBLIM and the MissBLIM modeled the missingness in a satisfactory way, in both a simulation study and an empirical application, depending on the process that generates the missingness: If the missing data-generating process is of type missing completely at random, then either IMBLIM or MissBLIM provide adequate fit to the data. However, if the pattern of missingness is functionally dependent upon unobservable features of the data (e.g., missing answers are more likely to be wrong), then only a correctly specified model of the missingness distribution provides an adequate fit to the data. (c) 2015 APA, all rights reserved).

  1. Missing incidents in community-dwelling people with dementia: understanding how these dangerous events differ from dementia-related ‘wandering’ is critical to assessment, intervention, and prevention.

    PubMed

    Rowe, Meredeth A; Greenblum, Catherine A; DʼAoust, Rita F

    2012-12-01

    At every stage of dementia, people with the condition are at risk for both missing incidents, in which they are unattended and unable to navigate a safe return to their caregiver, and "wandering," a term often used to describe repetitive locomotion with patterns such as lapping or pacing. By understanding the differences between these two phenomena, nurses can teach caregivers how to anticipate and prevent missing incidents, which are not necessarily related to wandering. The authors differentiate missing incidents from wandering, describe personal characteristics that may influence the outcomes in missing incidents, and suggest strategies for preventing and responding to missing incidents.

  2. HESS Opinions Catchments as meta-organisms - a new blueprint for hydrological modelling

    NASA Astrophysics Data System (ADS)

    Savenije, Hubert H. G.; Hrachowitz, Markus

    2017-02-01

    Catchment-scale hydrological models frequently miss essential characteristics of what determines the functioning of catchments. The most important active agent in catchments is the ecosystem. It manipulates and partitions moisture in a way that supports the essential functions of survival and productivity: infiltration of water, retention of moisture, mobilization and retention of nutrients, and drainage. Ecosystems do this in the most efficient way, establishing a continuous, ever-evolving feedback loop with the landscape and climatic drivers. In brief, hydrological systems are alive and have a strong capacity to adjust themselves to prevailing and changing environmental conditions. Although most models take Newtonian theory at heart, as best they can, what they generally miss is Darwinian theory on how an ecosystem evolves and adjusts its environment to maintain crucial hydrological functions. In addition, catchments, such as many other natural systems, do not only evolve over time, but develop features of spatial organization, including surface or sub-surface drainage patterns, as a by-product of this evolution. Models that fail to account for patterns and the associated feedbacks miss a critical element of how systems at the interface of atmosphere, biosphere and pedosphere function. In contrast to what is widely believed, relatively simple, semi-distributed conceptual models have the potential to accommodate organizational features and their temporal evolution in an efficient way, a reason for that being that because their parameters (and their evolution over time) are effective at the modelling scale, and thus integrate natural heterogeneity within the system, they may be directly inferred from observations at the same scale, reducing the need for calibration and related problems. In particular, the emergence of new and more detailed observation systems from space will lead towards a more robust understanding of spatial organization and its evolution. This will further permit the development of relatively simple time-dynamic functional relationships that can meaningfully represent spatial patterns and their evolution over time, even in poorly gauged environments.

  3. Construction of quality of life change patterns: example in oncology in a phase III therapeutic trial (FFCD 0307).

    PubMed

    Nuemi, Gillles; Devilliers, Hervé; Le Malicot, Karine; Guimbaud, Rosine; Lepage, Côme; Quantin, Catherine

    2015-09-22

    Quality of life data in cancerology are often difficult to summarize due to missing data and difficulty to analyze the pattern of evolution in different groups of patients. The aim of this work was to apply a new methodology to construct Quality of Life (QoL) change patterns within patients included in a clinical trial comparing to regimen of treatment in locally advanced eosogastric cancer. In this trial, QoL was assessed every 2 months by self-reported EORTC QLQ-C30 questionnaire. Physical dimension scores were analyzed. After multiple imputation of missing data, 27 statistical measures aiming to describe the variation of QoL measures among follow-up were computed for each patient. Based on these measures, patient were grouped into homogenous groups in terms of QoL variation pattern using a K-Means classification method. The mean QoL score at each time was graphically represented in each obtained pattern. Finally, clinical characteristic of patients in each pattern of QoL were described and compared. The trial included 416 patients and 1023 questionnaire were collected. 74% of patients were male with a mean ± SD age of 62 ± 11 years. 43% of scores were missing. Patients were grouped into four classes of homogeneous QoL variation patterns. 1) a Pattern of 24 (6%) patients showing improvement in QoL with a mean variation of +10.7 points on the 0-100 scale, 2) a Pattern of 171 (41 %) patients showing a stability 3) two Patterns of 78 (19%) and 143 (34%) patients respectively showing a deterioration of QoL with a mean variation of -67.2 and -67.6, respectively. There were no difference between patterns in terms of gender or age. Patients within "degradation" pattern had significantly lower performance status (p = 0.015), higher severe after-effects rate (p < 10-3) and death rate (p < 10-3). This work opens up perspectives for longitudinal data analysis with a high probability of missing values while providing a relevant graphical summary. Patterns of QoL evolution with clinical relevance may help to interpret longitudinal QoL data in Cancer studies.

  4. A general method for handling missing binary outcome data in randomized controlled trials.

    PubMed

    Jackson, Dan; White, Ian R; Mason, Dan; Sutton, Stephen

    2014-12-01

    The analysis of randomized controlled trials with incomplete binary outcome data is challenging. We develop a general method for exploring the impact of missing data in such trials, with a focus on abstinence outcomes. We propose a sensitivity analysis where standard analyses, which could include 'missing = smoking' and 'last observation carried forward', are embedded in a wider class of models. We apply our general method to data from two smoking cessation trials. A total of 489 and 1758 participants from two smoking cessation trials. The abstinence outcomes were obtained using telephone interviews. The estimated intervention effects from both trials depend on the sensitivity parameters used. The findings differ considerably in magnitude and statistical significance under quite extreme assumptions about the missing data, but are reasonably consistent under more moderate assumptions. A new method for undertaking sensitivity analyses when handling missing data in trials with binary outcomes allows a wide range of assumptions about the missing data to be assessed. In two smoking cessation trials the results were insensitive to all but extreme assumptions. © 2014 The Authors. Addiction published by John Wiley & Sons Ltd on behalf of Society for the Study of Addiction.

  5. Factors affecting first return to work following a compensable occupational back injury.

    PubMed

    Oleinick, A; Gluck, J V; Guire, K

    1996-11-01

    Occupational back injuries produced $27 billion in direct and indirect costs in 1988. Predictors of prolonged disability have generally been identified in selected clinical populations, but there have been few population-based studies using statewide registries from workers' compensation systems. This study uses a 1986 cohort of 8,628 Michigan workers with compensable back injuries followed to March 1, 1990. Cox proportional hazards analyses with nine categorical covariates identified factors predicting missed worktime for the first disability episode following the injury. The model distinguished factors affecting the acute (< or = 8 weeks) and chronic disability periods (> 8 weeks). The first disability episode following injury contains 69.6% of the missed worktime observed through follow-up. In the acute phase, which contributes 15.2% of first episode missed worktime, gender, age, number of dependents, industry (construction), occupation, and type of accident predict continued work disability. Marital status, weekly wage compensation rate, and establishment size do not. Beyond 8 weeks, age, establishment size and, to a lesser degree, wage compensation rate predict duration of work disability. Graphs show the predicted disability course for injured workers with specific covariate patterns. Future efforts to reduce missed worktime may require modifications in current clinical practice by patient age group and the development of new strategies to encourage small and medium-size employers to find ways to return their injured employees to work sooner. Recent federal statutes covering disabled workers will only partially correct the strong effect of employer establishment size.

  6. Local influence for generalized linear models with missing covariates.

    PubMed

    Shi, Xiaoyan; Zhu, Hongtu; Ibrahim, Joseph G

    2009-12-01

    In the analysis of missing data, sensitivity analyses are commonly used to check the sensitivity of the parameters of interest with respect to the missing data mechanism and other distributional and modeling assumptions. In this article, we formally develop a general local influence method to carry out sensitivity analyses of minor perturbations to generalized linear models in the presence of missing covariate data. We examine two types of perturbation schemes (the single-case and global perturbation schemes) for perturbing various assumptions in this setting. We show that the metric tensor of a perturbation manifold provides useful information for selecting an appropriate perturbation. We also develop several local influence measures to identify influential points and test model misspecification. Simulation studies are conducted to evaluate our methods, and real datasets are analyzed to illustrate the use of our local influence measures.

  7. Congenitally missing teeth (hypodontia): A review of the literature concerning the etiology, prevalence, risk factors, patterns and treatment

    PubMed Central

    Rakhshan, Vahid

    2015-01-01

    Congenitally missing teeth (CMT), or as usually called hypodontia, is a highly prevalent and costly dental anomaly. Besides an unfavorable appearance, patients with missing teeth may suffer from malocclusion, periodontal damage, insufficient alveolar bone growth, reduced chewing ability, inarticulate pronunciation and other problems. Treatment might be usually expensive and multidisciplinary. This highly frequent and yet expensive anomaly is of interest to numerous clinical, basic science and public health fields such as orthodontics, pediatric dentistry, prosthodontics, periodontics, maxillofacial surgery, anatomy, anthropology and even the insurance industry. This essay reviews the findings on the etiology, prevalence, risk factors, occurrence patterns, skeletal changes and treatments of congenitally missing teeth. It seems that CMT usually appears in females and in the permanent dentition. It is not conclusive whether it tends to occur more in the maxilla or mandible and also in the anterior versus posterior segments. It can accompany various complications and should be attended by expert teams as soon as possible. PMID:25709668

  8. The characteristics and distribution of dental anomalies in patients with cleft.

    PubMed

    Wu, Ting-Ting; Chen, Philip K T; Lo, Lun-Jou; Cheng, Min-Chi; Ko, Ellen Wen-Ching

    2011-01-01

    Dental anomalies associated with different severities of cleft lip and palate have been rarely reported. This retrospective study investigates the characteristics of dental anomalies associated with different types of cleft, and compares the dental anomaly traits based on sex and severity of cleft. Cleft patients born in 1995 with qualified diagnostic records from 7 to 11 years were included for evaluation. Records were retrieved from database of Chang Gung Craniofacial Center, including panoramic radiographs and intraoral photographs. In total, 196 patients with complete records were included in the evaluation. This study compares the dental anomalies associated with each type of cleft. The frequency of dental anomalies in the maxillary incisor area in the cleft palate (CP) group (20%) was significantly lower than that in other groups. The frequency of missing maxillary lateral incisors (MLIs) increased as the cleft severity increased. Supernumerary teeth and missing lower incisors exhibited the opposite trend. No sexual dimorphism appeared in terms of the frequencies of peg laterals and missing MLIs. The distribution patterns of missing MLIs and peg laterals in males, but not in females, were consistent for the three types of unilateral clefts. Regarding the characteristics of dental anomalies among the three unilateral clefts, missing MLIs, supernumerary teeth, and missing lower incisors were found to be related to cleft severity. The maxillary lateral incisor was the most affected tooth in the cleft area. The frequency of missing MLIs and peg laterals was not sexual dimorphic, but the distribution pattern was different between the sexes.

  9. Dealing with gene expression missing data.

    PubMed

    Brás, L P; Menezes, J C

    2006-05-01

    Compared evaluation of different methods is presented for estimating missing values in microarray data: weighted K-nearest neighbours imputation (KNNimpute), regression-based methods such as local least squares imputation (LLSimpute) and partial least squares imputation (PLSimpute) and Bayesian principal component analysis (BPCA). The influence in prediction accuracy of some factors, such as methods' parameters, type of data relationships used in the estimation process (i.e. row-wise, column-wise or both), missing rate and pattern and type of experiment [time series (TS), non-time series (NTS) or mixed (MIX) experiments] is elucidated. Improvements based on the iterative use of data (iterative LLS and PLS imputation--ILLSimpute and IPLSimpute), the need to perform initial imputations (modified PLS and Helland PLS imputation--MPLSimpute and HPLSimpute) and the type of relationships employed (KNNarray, LLSarray, HPLSarray and alternating PLS--APLSimpute) are proposed. Overall, it is shown that data set properties (type of experiment, missing rate and pattern) affect the data similarity structure, therefore influencing the methods' performance. LLSimpute and ILLSimpute are preferable in the presence of data with a stronger similarity structure (TS and MIX experiments), whereas PLS-based methods (MPLSimpute, IPLSimpute and APLSimpute) are preferable when estimating NTS missing data.

  10. Agriculture’s Soil Conservation Programs Miss Full Potential in the Fight against Soil Erosion.

    DTIC Science & Technology

    1983-11-28

    Soil Loss Equation ( USLE ) and Wind Erosion Equation can be used with a reasonable degree of accuracy. It is the intention of ASCS to expand VC/SL to...HD-R37 495 AGRICULTURE’S SOIL CONSERVATION PROGRAMS MISS FULL i/i POTENTIAL IN THE FIGHT.(U) GENERAL ACCOUNTING OFFICE WASHINGTON DC RESOURCES...GENERAL Report To The Congress OF THE UNITED STATES Agriculture’s Soil Conservation Programs Miss Full Potential In The Fight Against Soil Erosion

  11. Dark-field phase retrieval under the constraint of the Friedel symmetry in coherent X-ray diffraction imaging.

    PubMed

    Kobayashi, Amane; Sekiguchi, Yuki; Takayama, Yuki; Oroguchi, Tomotaka; Nakasako, Masayoshi

    2014-11-17

    Coherent X-ray diffraction imaging (CXDI) is a lensless imaging technique that is suitable for visualizing the structures of non-crystalline particles with micrometer to sub-micrometer dimensions from material science and biology. One of the difficulties inherent to CXDI structural analyses is the reconstruction of electron density maps of specimen particles from diffraction patterns because saturated detector pixels and a beam stopper result in missing data in small-angle regions. To overcome this difficulty, the dark-field phase-retrieval (DFPR) method has been proposed. The DFPR method reconstructs electron density maps from diffraction data, which are modified by multiplying Gaussian masks with an observed diffraction pattern in the high-angle regions. In this paper, we incorporated Friedel centrosymmetry for diffraction patterns into the DFPR method to provide a constraint for the phase-retrieval calculation. A set of model simulations demonstrated that this constraint dramatically improved the probability of reconstructing correct electron density maps from diffraction patterns that were missing data in the small-angle region. In addition, the DFPR method with the constraint was applied successfully to experimentally obtained diffraction patterns with significant quantities of missing data. We also discuss this method's limitations with respect to the level of Poisson noise in X-ray detection.

  12. Taking into account the impact of attrition on the assessment of response shift and true change: a multigroup structural equation modeling approach.

    PubMed

    Verdam, Mathilde G E; Oort, Frans J; van der Linden, Yvette M; Sprangers, Mirjam A G

    2015-03-01

    Missing data due to attrition present a challenge for the assessment and interpretation of change and response shift in HRQL outcomes. The objective was to handle such missingness and to assess response shift and 'true change' with the use of an attrition-based multigroup structural equation modeling (SEM) approach. Functional limitations and health impairments were measured in 1,157 cancer patients, who were treated with palliative radiotherapy for painful bone metastases, before [time (T) 0], every week after treatment (T1 through T12), and then monthly for up to 2 years (T13 through T24). To handle missing data due to attrition, the SEM procedure was extended to a multigroup approach, in which we distinguished three groups: short survival (3-5 measurements), medium survival (6-12 measurements), and long survival (>12 measurements). Attrition after third, sixth, and 13th measurement occasions was 11, 24, and 41 %, respectively. Results show that patterns of change in functional limitations and health impairments differ between patients with short, medium, or long survival. Moreover, three response-shift effects were detected: recalibration of 'pain' and 'sickness' and reprioritization of 'physical functioning.' If response-shift effects would not have been taken into account, functional limitations and health impairments would generally be underestimated across measurements. The multigroup SEM approach enables the analysis of data from patients with different patterns of missing data due to attrition. This approach does not only allow for detection of response shift and assessment of true change across measurements, but also allow for detection of differences in response shift and true change across groups of patients with different attrition rates.

  13. Allele-sharing models: LOD scores and accurate linkage tests.

    PubMed

    Kong, A; Cox, N J

    1997-11-01

    Starting with a test statistic for linkage analysis based on allele sharing, we propose an associated one-parameter model. Under general missing-data patterns, this model allows exact calculation of likelihood ratios and LOD scores and has been implemented by a simple modification of existing software. Most important, accurate linkage tests can be performed. Using an example, we show that some previously suggested approaches to handling less than perfectly informative data can be unacceptably conservative. Situations in which this model may not perform well are discussed, and an alternative model that requires additional computations is suggested.

  14. Allele-sharing models: LOD scores and accurate linkage tests.

    PubMed Central

    Kong, A; Cox, N J

    1997-01-01

    Starting with a test statistic for linkage analysis based on allele sharing, we propose an associated one-parameter model. Under general missing-data patterns, this model allows exact calculation of likelihood ratios and LOD scores and has been implemented by a simple modification of existing software. Most important, accurate linkage tests can be performed. Using an example, we show that some previously suggested approaches to handling less than perfectly informative data can be unacceptably conservative. Situations in which this model may not perform well are discussed, and an alternative model that requires additional computations is suggested. PMID:9345087

  15. Missing Data in Clinical Studies: Issues and Methods

    PubMed Central

    Ibrahim, Joseph G.; Chu, Haitao; Chen, Ming-Hui

    2012-01-01

    Missing data are a prevailing problem in any type of data analyses. A participant variable is considered missing if the value of the variable (outcome or covariate) for the participant is not observed. In this article, various issues in analyzing studies with missing data are discussed. Particularly, we focus on missing response and/or covariate data for studies with discrete, continuous, or time-to-event end points in which generalized linear models, models for longitudinal data such as generalized linear mixed effects models, or Cox regression models are used. We discuss various classifications of missing data that may arise in a study and demonstrate in several situations that the commonly used method of throwing out all participants with any missing data may lead to incorrect results and conclusions. The methods described are applied to data from an Eastern Cooperative Oncology Group phase II clinical trial of liver cancer and a phase III clinical trial of advanced non–small-cell lung cancer. Although the main area of application discussed here is cancer, the issues and methods we discuss apply to any type of study. PMID:22649133

  16. A general method for handling missing binary outcome data in randomized controlled trials

    PubMed Central

    Jackson, Dan; White, Ian R; Mason, Dan; Sutton, Stephen

    2014-01-01

    Aims The analysis of randomized controlled trials with incomplete binary outcome data is challenging. We develop a general method for exploring the impact of missing data in such trials, with a focus on abstinence outcomes. Design We propose a sensitivity analysis where standard analyses, which could include ‘missing = smoking’ and ‘last observation carried forward’, are embedded in a wider class of models. Setting We apply our general method to data from two smoking cessation trials. Participants A total of 489 and 1758 participants from two smoking cessation trials. Measurements The abstinence outcomes were obtained using telephone interviews. Findings The estimated intervention effects from both trials depend on the sensitivity parameters used. The findings differ considerably in magnitude and statistical significance under quite extreme assumptions about the missing data, but are reasonably consistent under more moderate assumptions. Conclusions A new method for undertaking sensitivity analyses when handling missing data in trials with binary outcomes allows a wide range of assumptions about the missing data to be assessed. In two smoking cessation trials the results were insensitive to all but extreme assumptions. PMID:25171441

  17. Using missing ordinal patterns to detect nonlinearity in time series data.

    PubMed

    Kulp, Christopher W; Zunino, Luciano; Osborne, Thomas; Zawadzki, Brianna

    2017-08-01

    The number of missing ordinal patterns (NMP) is the number of ordinal patterns that do not appear in a series after it has been symbolized using the Bandt and Pompe methodology. In this paper, the NMP is demonstrated as a test for nonlinearity using a surrogate framework in order to see if the NMP for a series is statistically different from the NMP of iterative amplitude adjusted Fourier transform (IAAFT) surrogates. It is found that the NMP works well as a test statistic for nonlinearity, even in the cases of very short time series. Both model and experimental time series are used to demonstrate the efficacy of the NMP as a test for nonlinearity.

  18. 32 CFR 718.1 - General provisions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Defense Department of Defense (Continued) DEPARTMENT OF THE NAVY PERSONNEL MISSING PERSONS ACT § 718.1 General provisions. (a) Under the provisions of the Missing Persons Act, as amended, a finding of... presumptive death are never made when the “missing” status has not continued for at least 12 months. Whenever...

  19. 32 CFR 718.1 - General provisions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Defense Department of Defense (Continued) DEPARTMENT OF THE NAVY PERSONNEL MISSING PERSONS ACT § 718.1 General provisions. (a) Under the provisions of the Missing Persons Act, as amended, a finding of... presumptive death are never made when the “missing” status has not continued for at least 12 months. Whenever...

  20. Missing Oral Health-Related Data in the interRAI-HC - Associations with Selected Variables of General Health and the Effect of Multiple Imputation on the Relationship between Oral and General Health.

    PubMed

    Krausch-Hofmann, Stefanie; Bogaerts, Kris; Hofmann, Michael; de Almeida Mello, Johanna; Fávaro Moreira, Nádia Cristina; Lesaffre, Emmanuel; Declerck, Dominique; Declercq, Anja; Duyck, Joke

    2015-01-01

    Missing data within the comprehensive geriatric assessment of the interRAI suite of assessment instruments potentially imply the under-detection of conditions that require care as well as the risk of biased statistical results. Impaired oral health in older individuals has to be registered accurately as it causes pain and discomfort and is related to the general health status. This study was based on interRAI-Home Care (HC) baseline data from 7590 subjects (mean age 81.2 years, SD 6.9) in Belgium. It was investigated if missingness of the oral health-related items was associated with selected variables of general health. It was also determined if multiple imputation of missing data affected the associations between oral and general health. Multivariable logistic regression was used to determine if the prevalence of missingness in the oral health-related variables was associated with activities of daily life (ADLH), cognitive performance (CPS2) and depression (DRS). Associations between oral health and ADLH, CPS2 and DRS were determined, with missing data treated by 1. the complete-case technique and 2. by multiple imputation, and results were compared. The individual oral health-related variables had a similar proportion of missing values, ranging from 16.3% to 17.2%. The prevalence of missing data in all oral health-related variables was significantly associated with symptoms of depression (dental prosthesis use OR 1.66, CI 1.41-1.95; damaged teeth OR 1.74, CI 1.48-2.04; chewing problems OR 1.74, CI 1.47-2.05; dry mouth OR 1.65, CI 1.40-1.94). Missingness in damaged teeth (OR 1.27, CI 1.08-1.48), chewing problems (OR 1.22, CI 1.04-1.44) and dry mouth (OR 1.23, CI 1.05-1.44) occurred more frequently in cognitively impaired subjects. ADLH was not associated with the prevalence of missing data. When comparing the complete-case technique with the multiple imputation approach, nearly identical odds ratios characterized the associations between oral and general health. Cognitively impaired and depressive individuals had a higher risk of missing oral health-related information. Associations between oral health and ADLH, CPS2 and DRS were not influenced by multiple imputation of missing data. Further research should concentrate on the mechanisms that mediate the occurrence of missingness to develop preventative strategies.

  1. 12 CFR 1282.15 - General requirements.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...). (3) Missing data or information. When an Enterprise lacks sufficient data or information to determine.... Mortgage purchases with missing data in excess of the maximum will be included in the denominator and... missing borrower incomes (as determined by FHFA based on the most recent Home Mortgage Disclosure Act data...

  2. Analysis of Longitudinal Outcome Data with Missing Values in Total Knee Arthroplasty.

    PubMed

    Kang, Yeon Gwi; Lee, Jang Taek; Kang, Jong Yeal; Kim, Ga Hye; Kim, Tae Kyun

    2016-01-01

    We sought to determine the influence of missing data on the statistical results, and to determine which statistical method is most appropriate for the analysis of longitudinal outcome data of TKA with missing values among repeated measures ANOVA, generalized estimating equation (GEE) and mixed effects model repeated measures (MMRM). Data sets with missing values were generated with different proportion of missing data, sample size and missing-data generation mechanism. Each data set was analyzed with three statistical methods. The influence of missing data was greater with higher proportion of missing data and smaller sample size. MMRM tended to show least changes in the statistics. When missing values were generated by 'missing not at random' mechanism, no statistical methods could fully avoid deviations in the results. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Correlation of missed doses of enoxaparin with increased incidence of deep vein thrombosis in trauma and general surgery patients.

    PubMed

    Louis, Scott G; Sato, Misa; Geraci, Travis; Anderson, Ross; Cho, S David; Van, Philbert Y; Barton, Jeffrey S; Riha, Gordon M; Underwood, Samantha; Differding, Jerome; Watters, Jennifer M; Schreiber, Martin A

    2014-04-01

    Enoxaparin sodium is widely used for deep vein thrombosis (DVT) prophylaxis, yet DVT rates remain high in the trauma and general surgery populations. Missed doses during hospitalization are common. To determine if missed doses of enoxaparin correlate with DVT formation. Data were prospectively collected among 202 trauma and general surgery patients admitted to a level I trauma center. Deep vein thrombosis screening was performed using a rigorous standardized protocol. The overall incidence of DVT was 15.8%. In total, 58.9% of patients missed at least 1 dose of enoxaparin. The DVTs occurred in 23.5% of patients who missed at least 1 dose and in 4.8% of patients who did not (P < .01). On univariate analysis, the need for mechanical ventilation (71.8% vs 44.1%), the performance of more than 1 operation (59.3% vs 40.0%), and male sex (75% vs 56%) were associated with DVT formation (P < .05 for all). A bivariate logistic regression was then performed, which revealed age 50 years or older and interrupted enoxaparin therapy as the only independent risk factors for DVT formation. The DVT rate did not differ between trauma and general surgery populations or in patients receiving once-daily vs twice-daily dosing regimens. Interrupted enoxaparin therapy and age 50 years or older are associated with DVT formation among trauma and general surgery patients. Missed doses occur commonly and are the only identified risk factor for DVT that can be ameliorated by physicians. Efforts to minimize interrupted enoxaparin prophylaxis in patients at risk for DVT should be optimized.

  4. Analysis of car-to-bicycle approach patterns for developing active safety devices.

    PubMed

    Matsui, Yasuhiro; Oikawa, Shoko; Hitosugi, Masahito

    2016-05-18

    To reduce the severity of injuries and the number of cyclist deaths in traffic accidents, active safety devices providing cyclist detection are considered to be effective countermeasures. The features of car-to-bicycle collisions need to be known in detail to develop such safety devices. The study investigated near-miss situations captured by drive recorders installed in passenger cars. Because similarities in the approach patterns between near-miss incidents and real-world fatal cyclist accidents in Japan were confirmed, we analyzed the 229 near-miss incident data via video capturing bicycles crossing the road in front of forward-moving cars. Using a video frame captured by a drive recorder, the time to collision (TTC) was calculated from the car's velocity and the distance between the car and bicycle at the moment when the bicycle initially appeared. The average TTC in the cases where bicycles emerged from behind obstructions was shorter than that in the cases where drivers had unobstructed views of the bicycles. In comparing the TTC of car-to-bicycle near-miss incidents to the previously obtained results of car-to-pedestrian near-miss incidents, it was determined that the average TTC in car-to-bicycle near-miss incidents was significantly longer than that in car-to-pedestrian near-miss incidents. When considering the TTC in the test protocol of evaluation for safety performance of active safety devices, we propose individual TTCs for evaluation of cyclist and pedestrian detections, respectively. In the test protocols, the following 2 scenarios should be employed: bicycle emerging from behind an unobstructed view and bicycle emerging from behind obstructions.

  5. Multilevel non-contiguous spinal injuries: incidence and patterns based on whole spine MRI.

    PubMed

    Kanna, Rishi Mugesh; Gaike, Chandrasekar V; Mahesh, Anupama; Shetty, Ajoy Prasad; Rajasekaran, S

    2016-04-01

    Multi-level non-contiguous spinal injuries are not uncommon and their incidence varies from 1.6 to 77% depending on the type of imaging modality used. Delayed diagnosis and missed spinal injuries in non-contiguous spine fractures have been frequently described which can result in significant pain, deformity and neurological deficit. The efficacy of whole spine MRI in detecting asymptomatic significant vertebral fractures is not known. Consecutive spinal injury patients treated between 2011 and 2013 were retrospectively evaluated based on clinical and radiographic records. Patients' demographics, mode of injury, presence of associated injuries, clinical symptoms and the presence of neurological deficit were studied. Radiographs of the fractured region and whole spine MRI were evaluated for the presence of multi-level injuries. Among 484 patients, 95 (19.62%) patients had multilevel injuries including 86 (17.76%) with non-contiguous injuries. Five common patterns of non-contiguous spinal injuries were observed. Pattern I: cervical and thoracic--29.1%, Pattern II: thoracolumbar and lumbosacral--22.1%, Pattern III: thoracic and thoracolumbar--12.8 %, Pattern IV: cervical and thoracolumbar--9.1% and Pattern V: lumbosacral and associated injuries--9.0 %. The incidence of intra-regional non-contiguous injuries was 17.4%. Whole spine MRI scan detected 24 (28.6%) missed secondary injuries of which 5 were unstable. The incidence of multilevel non-contiguous spine injury using whole spine MRI imaging is 17.76%. Five different patterns of multi-level non-contiguous injuries were found with the most common pattern being the cervical and thoracic level injuries. The incidence of unstable injuries can be as high as 21% of missed secondary injuries.

  6. A Simple Approach to Inference in Covariance Structure Modeling with Missing Data: Bayesian Analysis. Project 2.4, Quantitative Models To Monitor the Status and Progress of Learning and Performance and Their Antecedents.

    ERIC Educational Resources Information Center

    Muthen, Bengt

    This paper investigates methods that avoid using multiple groups to represent the missing data patterns in covariance structure modeling, attempting instead to do a single-group analysis where the only action the analyst has to take is to indicate that data is missing. A new covariance structure approach developed by B. Muthen and G. Arminger is…

  7. Should genes with missing data be excluded from phylogenetic analyses?

    PubMed

    Jiang, Wei; Chen, Si-Yun; Wang, Hong; Li, De-Zhu; Wiens, John J

    2014-11-01

    Phylogeneticists often design their studies to maximize the number of genes included but minimize the overall amount of missing data. However, few studies have addressed the costs and benefits of adding characters with missing data, especially for likelihood analyses of multiple loci. In this paper, we address this topic using two empirical data sets (in yeast and plants) with well-resolved phylogenies. We introduce varying amounts of missing data into varying numbers of genes and test whether the benefits of excluding genes with missing data outweigh the costs of excluding the non-missing data that are associated with them. We also test if there is a proportion of missing data in the incomplete genes at which they cease to be beneficial or harmful, and whether missing data consistently bias branch length estimates. Our results indicate that adding incomplete genes generally increases the accuracy of phylogenetic analyses relative to excluding them, especially when there is a high proportion of incomplete genes in the overall dataset (and thus few complete genes). Detailed analyses suggest that adding incomplete genes is especially helpful for resolving poorly supported nodes. Given that we find that excluding genes with missing data often decreases accuracy relative to including these genes (and that decreases are generally of greater magnitude than increases), there is little basis for assuming that excluding these genes is necessarily the safer or more conservative approach. We also find no evidence that missing data consistently bias branch length estimates. Copyright © 2014 Elsevier Inc. All rights reserved.

  8. Detection of Parent-of-Origin Effects Using General Pedigree Data

    PubMed Central

    Zhou, Ji-Yuan; Ding, Jie; Fung, Wing K.; Lin, Shili

    2010-01-01

    Genomic imprinting is an important epigenetic factor in complex traits study, which has generally been examined by testing for parent-of-origin effects of alleles. For a diallelic marker locus, the parental-asymmetry test (PAT) based on case-parents trios and its extensions to incomplete nuclear families (1-PAT and C-PAT) are simple and powerful for detecting parent-of-origin effects. However, these methods are suitable only for nuclear families and thus are not amenable to general pedigree data. Use of data from extended pedigrees, if available, may lead to more powerful methods than randomly selecting one two-generation nuclear family from each pedigree. In this study, we extend PAT to accommodate general pedigree data by proposing the pedigree PAT (PPAT) statistic, which uses all informative family trios from pedigrees. To fully utilize pedigrees with some missing genotypes, we further develop the Monte Carlo (MC) PPAT (MCPPAT) statistic based on MC sampling and estimation. Extensive simulations were carried out to evaluate the performance of the proposed methods. Under the assumption that the pedigrees and their associated affection patterns are randomly drawn from a population of pedigrees with at least one affected offspring, we demonstrated that MCPPAT is a valid test for parent-of-origin effects in the presence of association. Further, MCPPAT is much more powerful compared to PAT for trios or even PPAT for all informative family trios from the same pedigrees if there is missing data. Application of the proposed methods to a rheumatoid arthritis dataset further demonstrates the advantage of MCPPAT. PMID:19676055

  9. Quality Assurance of NCI Thesaurus by Mining Structural-Lexical Patterns

    PubMed Central

    Abeysinghe, Rashmie; Brooks, Michael A.; Talbert, Jeffery; Licong, Cui

    2017-01-01

    Quality assurance of biomedical terminologies such as the National Cancer Institute (NCI) Thesaurus is an essential part of the terminology management lifecycle. We investigate a structural-lexical approach based on non-lattice subgraphs to automatically identify missing hierarchical relations and missing concepts in the NCI Thesaurus. We mine six structural-lexical patterns exhibiting in non-lattice subgraphs: containment, union, intersection, union-intersection, inference-contradiction, and inference union. Each pattern indicates a potential specific type of error and suggests a potential type of remediation. We found 809 non-lattice subgraphs with these patterns in the NCI Thesaurus (version 16.12d). Domain experts evaluated a random sample of 50 small non-lattice subgraphs, of which 33 were confirmed to contain errors and make correct suggestions (33/50 = 66%). Of the 25 evaluated subgraphs revealing multiple patterns, 22 were verified correct (22/25 = 88%). This shows the effectiveness of our structurallexical-pattern-based approach in detecting errors and suggesting remediations in the NCI Thesaurus. PMID:29854100

  10. Misconceptions on Missing Data in RAD-seq Phylogenetics with a Deep-scale Example from Flowering Plants.

    PubMed

    Eaton, Deren A R; Spriggs, Elizabeth L; Park, Brian; Donoghue, Michael J

    2017-05-01

    Restriction-site associated DNA (RAD) sequencing and related methods rely on the conservation of enzyme recognition sites to isolate homologous DNA fragments for sequencing, with the consequence that mutations disrupting these sites lead to missing information. There is thus a clear expectation for how missing data should be distributed, with fewer loci recovered between more distantly related samples. This observation has led to a related expectation: that RAD-seq data are insufficiently informative for resolving deeper scale phylogenetic relationships. Here we investigate the relationship between missing information among samples at the tips of a tree and information at edges within it. We re-analyze and review the distribution of missing data across ten RAD-seq data sets and carry out simulations to determine expected patterns of missing information. We also present new empirical results for the angiosperm clade Viburnum (Adoxaceae, with a crown age >50 Ma) for which we examine phylogenetic information at different depths in the tree and with varied sequencing effort. The total number of loci, the proportion that are shared, and phylogenetic informativeness varied dramatically across the examined RAD-seq data sets. Insufficient or uneven sequencing coverage accounted for similar proportions of missing data as dropout from mutation-disruption. Simulations reveal that mutation-disruption, which results in phylogenetically distributed missing data, can be distinguished from the more stochastic patterns of missing data caused by low sequencing coverage. In Viburnum, doubling sequencing coverage nearly doubled the number of parsimony informative sites, and increased by >10X the number of loci with data shared across >40 taxa. Our analysis leads to a set of practical recommendations for maximizing phylogenetic information in RAD-seq studies. [hierarchical redundancy; phylogenetic informativeness; quartet informativeness; Restriction-site associated DNA (RAD) sequencing; sequencing coverage; Viburnum.]. © The authors 2016. Published by Oxford University Press, on behalf of the Society of Systematic Biologists. All rights reserved. For permissions, please e-mail: journals.permission@oup.com.

  11. Comparison of Modern Methods for Analyzing Repeated Measures Data with Missing Values

    ERIC Educational Resources Information Center

    Vallejo, G.; Fernandez, M. P.; Livacic-Rojas, P. E.; Tuero-Herrero, E.

    2011-01-01

    Missing data are a pervasive problem in many psychological applications in the real world. In this article we study the impact of dropout on the operational characteristics of several approaches that can be easily implemented with commercially available software. These approaches include the covariance pattern model based on an unstructured…

  12. Electronics Devices and Materials

    DTIC Science & Technology

    2008-03-17

    Molecular -bea epitaxy MCNPX ............... Software code Misse6 ................. Satellite expected to carry ORMatE-I Misse7...patterning using electron beam lithography), spaces (class 1000 clean benches), and skills (appropriate mix of skilled technicians and professionals...34 Process samples for various projects such as Antimode Base High Electron Mobility Transistors ( HEMT ) and Double Heterojuction Bipolar Transistors

  13. Prevalence of urinary tract infection in acutely unwell children in general practice: a prospective study with systematic urine sampling.

    PubMed

    O'Brien, Kathryn; Edwards, Adrian; Hood, Kerenza; Butler, Christopher C

    2013-02-01

    Urinary tract infection (UTI) in children may be associated with long-term complications that could be prevented by prompt treatment. To determine the prevalence of UTI in acutely ill children ≤ 5 years presenting in general practice and to explore patterns of presenting symptoms and urine sampling strategies. Prospective observational study with systematic urine sampling, in general practices in Wales, UK. In total, 1003 children were recruited from 13 general practices between March 2008 and July 2010. The prevalence of UTI was determined and multivariable analysis performed to determine the probability of UTI. Out of 597 (60.0%) children who provided urine samples within 2 days, the prevalence of UTI was 5.9% (95% confidence interval [CI] = 4.3% to 8.0%) overall, 7.3% in those < 3 years and 3.2% in 3-5 year olds. Neither a history of fever nor the absence of an alternative source of infection was associated with UTI (P = 0.64; P = 0.69, respectively). The probability of UTI in children aged ≥3 years without increased urinary frequency or dysuria was 2%. The probability of UTI was ≥5% in all other groups. Urine sampling based purely on GP suspicion would have missed 80% of UTIs, while a sampling strategy based on current guidelines would have missed 50%. Approximately 6% of acutely unwell children presenting to UK general practice met the criteria for a laboratory diagnosis of UTI. This higher than previously recognised prior probability of UTI warrants raised awareness of the condition and suggests clinicians should lower their threshold for urine sampling in young children. The absence of fever or presence of an alternative source of infection, as emphasised in current guidelines, may not rule out UTI in young children with adequate certainty.

  14. Facebook intrusion, fear of missing out, narcissism, and life satisfaction: A cross-sectional study.

    PubMed

    Błachnio, Agata; Przepiórka, Aneta

    2018-01-01

    Facebook is one of the most popular social networking sites. The present paper examines the relations between fear of missing out, narcissism, Facebook intrusion, and life satisfaction. We hypothesized that the fear of missing out and narcissism would play a significant role in Facebook intrusion. The participants in the study were 360 Polish users of Facebook. We administered the Facebook Intrusion Scale, the Fear of Missing Out Scale, the Narcissistic Personality Inventory, and the Satisfaction with Life Scale. The results showed that a high level of fear of missing out and high narcissism are predictors of Facebook intrusion, while a low level of fear of missing out and high narcissism are related to satisfaction with life. Our findings provide a more comprehensive picture of the predictors of Facebook intrusion and reveal interesting patterns. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. The missing impact craters on Venus

    NASA Technical Reports Server (NTRS)

    Speidel, D. H.

    1993-01-01

    The size-frequency pattern of the 842 impact craters on Venus measured to date can be well described (across four standard deviation units) as a single log normal distribution with a mean crater diameter of 14.5 km. This result was predicted in 1991 on examination of the initial Magellan analysis. If this observed distribution is close to the real distribution, the 'missing' 90 percent of the small craters and the 'anomalous' lack of surface splotches may thus be neither missing nor anomalous. I think that the missing craters and missing splotches can be satisfactorily explained by accepting that the observed distribution approximates the real one, that it is not craters that are missing but the impactors. What you see is what you got. The implication that Venus crossing impactors would have the same type of log normal distribution is consistent with recently described distribution for terrestrial craters and Earth crossing asteroids.

  16. Imputation of missing data in time series for air pollutants

    NASA Astrophysics Data System (ADS)

    Junger, W. L.; Ponce de Leon, A.

    2015-02-01

    Missing data are major concerns in epidemiological studies of the health effects of environmental air pollutants. This article presents an imputation-based method that is suitable for multivariate time series data, which uses the EM algorithm under the assumption of normal distribution. Different approaches are considered for filtering the temporal component. A simulation study was performed to assess validity and performance of proposed method in comparison with some frequently used methods. Simulations showed that when the amount of missing data was as low as 5%, the complete data analysis yielded satisfactory results regardless of the generating mechanism of the missing data, whereas the validity began to degenerate when the proportion of missing values exceeded 10%. The proposed imputation method exhibited good accuracy and precision in different settings with respect to the patterns of missing observations. Most of the imputations obtained valid results, even under missing not at random. The methods proposed in this study are implemented as a package called mtsdi for the statistical software system R.

  17. Incorrect support and missing center tolerances of phasing algorithms

    DOE PAGES

    Huang, Xiaojing; Nelson, Johanna; Steinbrener, Jan; ...

    2010-01-01

    In x-ray diffraction microscopy, iterative algorithms retrieve reciprocal space phase information, and a real space image, from an object's coherent diffraction intensities through the use of a priori information such as a finite support constraint. In many experiments, the object's shape or support is not well known, and the diffraction pattern is incompletely measured. We describe here computer simulations to look at the effects of both of these possible errors when using several common reconstruction algorithms. Overly tight object supports prevent successful convergence; however, we show that this can often be recognized through pathological behavior of the phase retrieval transfermore » function. Dynamic range limitations often make it difficult to record the central speckles of the diffraction pattern. We show that this leads to increasing artifacts in the image when the number of missing central speckles exceeds about 10, and that the removal of unconstrained modes from the reconstructed image is helpful only when the number of missing central speckles is less than about 50. In conclusion, this simulation study helps in judging the reconstructability of experimentally recorded coherent diffraction patterns.« less

  18. Landscape of supersymmetric particle mass hierarchies and their signature space at the CERN Large Hadron Collider.

    PubMed

    Feldman, Daniel; Liu, Zuowei; Nath, Pran

    2007-12-21

    The minimal supersymmetric standard model with soft breaking has a large landscape of supersymmetric particle mass hierarchies. This number is reduced significantly in well-motivated scenarios such as minimal supergravity and alternatives. We carry out an analysis of the landscape for the first four lightest particles and identify at least 16 mass patterns, and provide benchmarks for each. We study the signature space for the patterns at the CERN Large Hadron Collider by analyzing the lepton+ (jet> or =2) + missing P{T} signals with 0, 1, 2, and 3 leptons. Correlations in missing P{T} are also analyzed. It is found that even with 10 fb{-1} of data a significant discrimination among patterns emerges.

  19. An approximate generalized linear model with random effects for informative missing data.

    PubMed

    Follmann, D; Wu, M

    1995-03-01

    This paper develops a class of models to deal with missing data from longitudinal studies. We assume that separate models for the primary response and missingness (e.g., number of missed visits) are linked by a common random parameter. Such models have been developed in the econometrics (Heckman, 1979, Econometrica 47, 153-161) and biostatistics (Wu and Carroll, 1988, Biometrics 44, 175-188) literature for a Gaussian primary response. We allow the primary response, conditional on the random parameter, to follow a generalized linear model and approximate the generalized linear model by conditioning on the data that describes missingness. The resultant approximation is a mixed generalized linear model with possibly heterogeneous random effects. An example is given to illustrate the approximate approach, and simulations are performed to critique the adequacy of the approximation for repeated binary data.

  20. An auxiliary optimization method for complex public transit route network based on link prediction

    NASA Astrophysics Data System (ADS)

    Zhang, Lin; Lu, Jian; Yue, Xianfei; Zhou, Jialin; Li, Yunxuan; Wan, Qian

    2018-02-01

    Inspired by the missing (new) link prediction and the spurious existing link identification in link prediction theory, this paper establishes an auxiliary optimization method for public transit route network (PTRN) based on link prediction. First, link prediction applied to PTRN is described, and based on reviewing the previous studies, the summary indices set and its algorithms set are collected for the link prediction experiment. Second, through analyzing the topological properties of Jinan’s PTRN established by the Space R method, we found that this is a typical small-world network with a relatively large average clustering coefficient. This phenomenon indicates that the structural similarity-based link prediction will show a good performance in this network. Then, based on the link prediction experiment of the summary indices set, three indices with maximum accuracy are selected for auxiliary optimization of Jinan’s PTRN. Furthermore, these link prediction results show that the overall layout of Jinan’s PTRN is stable and orderly, except for a partial area that requires optimization and reconstruction. The above pattern conforms to the general pattern of the optimal development stage of PTRN in China. Finally, based on the missing (new) link prediction and the spurious existing link identification, we propose optimization schemes that can be used not only to optimize current PTRN but also to evaluate PTRN planning.

  1. Missing links: the genetic architecture of flowers [correction of flower] and floral diversification.

    PubMed

    Soltis, Douglas E; Soltis, Pamela S; Albert, Victor A; Oppenheimer, David G; dePamphilis, Claude W; Ma, Hong; Frohlich, Michael W; Theissen, Günter

    2002-01-01

    To understand the genetic architecture of floral development, including the origin and subsequent diversification of the flower, data are needed not only for a few model organisms but also for gymnosperms, basal angiosperm lineages and early-diverging eudicots. We must link what is known about derived model plants such as Arabidopsis, snapdragon and maize with other angiosperms. To this end, we suggest a massive evolutionary genomics effort focused on the identification and expression patterns of floral genes and elucidation of their expression patterns in 'missing-link' taxa differing in the arrangement, number and organization of floral parts.

  2. Addressing the Missing Instructional Data Problem: Using a Teacher Log to Document Tier 1 Instruction

    ERIC Educational Resources Information Center

    Kurz, Alexander; Elliott, Stephen N.; Roach, Andrew T.

    2015-01-01

    Response-to-intervention (RTI) systems posit that Tier 1 consists of high-quality general classroom instruction using evidence-based methods to address the needs of most students. However, data on the extent to which general education teachers provide such instruction are rarely collected. This missing instructional data problem may result in RTI…

  3. Erratum to Surface‐wave green’s tensors in the near field

    USGS Publications Warehouse

    Haney, Matthew M.; Hisashi Nakahara,

    2016-01-01

    Haney and Nakahara (2014) derived expressions for surface‐wave Green’s tensors that included near‐field behavior. Building on the result for a force source, Haney and Nakahara (2014) further derived expressions for a general point moment tensor source using the exact Green’s tensors. However, it has come to our attention that, although the Green’s tensors were correct, the resulting expressions for a general point moment tensor source were missing some terms. In this erratum, we provide updated expressions with these missing terms. The inclusion of the missing terms changes the example given in Haney and Nakahara (2014).

  4. 40 CFR 75.58 - General recordkeeping provisions for specific situations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... C to this part, for each hour of missing SO2 concentration or volumetric flow data: (i) The... owner or operator shall record: (i) Parametric data which demonstrate, for each hour of missing SO2 or... indicating, for each hour of missing SO2 or NOX emission data, either that the add-on emission controls are...

  5. 40 CFR 75.58 - General recordkeeping provisions for specific situations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... C to this part, for each hour of missing SO2 concentration or volumetric flow data: (i) The... owner or operator shall record: (i) Parametric data which demonstrate, for each hour of missing SO2 or... indicating, for each hour of missing SO2 or NOX emission data, either that the add-on emission controls are...

  6. 40 CFR 75.58 - General recordkeeping provisions for specific situations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... C to this part, for each hour of missing SO2 concentration or volumetric flow data: (i) The... owner or operator shall record: (i) Parametric data which demonstrate, for each hour of missing SO2 or... indicating, for each hour of missing SO2 or NOX emission data, either that the add-on emission controls are...

  7. 40 CFR 75.58 - General recordkeeping provisions for specific situations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... C to this part, for each hour of missing SO2 concentration or volumetric flow data: (i) The... owner or operator shall record: (i) Parametric data which demonstrate, for each hour of missing SO2 or... indicating, for each hour of missing SO2 or NOX emission data, either that the add-on emission controls are...

  8. Handling Missing Data: Analysis of a Challenging Data Set Using Multiple Imputation

    ERIC Educational Resources Information Center

    Pampaka, Maria; Hutcheson, Graeme; Williams, Julian

    2016-01-01

    Missing data is endemic in much educational research. However, practices such as step-wise regression common in the educational research literature have been shown to be dangerous when significant data are missing, and multiple imputation (MI) is generally recommended by statisticians. In this paper, we provide a review of these advances and their…

  9. A group evolving-based framework with perturbations for link prediction

    NASA Astrophysics Data System (ADS)

    Si, Cuiqi; Jiao, Licheng; Wu, Jianshe; Zhao, Jin

    2017-06-01

    Link prediction is a ubiquitous application in many fields which uses partially observed information to predict absence or presence of links between node pairs. The group evolving study provides reasonable explanations on the behaviors of nodes, relations between nodes and community formation in a network. Possible events in group evolution include continuing, growing, splitting, forming and so on. The changes discovered in networks are to some extent the result of these events. In this work, we present a group evolving-based characterization of node's behavioral patterns, and via which we can estimate the probability they tend to interact. In general, the primary aim of this paper is to offer a minimal toy model to detect missing links based on evolution of groups and give a simpler explanation on the rationality of the model. We first introduce perturbations into networks to obtain stable cluster structures, and the stable clusters determine the stability of each node. Then fluctuations, another node behavior, are assumed by the participation of each node to its own belonging group. Finally, we demonstrate that such characteristics allow us to predict link existence and propose a model for link prediction which outperforms many classical methods with a decreasing computational time in large scales. Encouraging experimental results obtained on real networks show that our approach can effectively predict missing links in network, and even when nearly 40% of the edges are missing, it also retains stationary performance.

  10. Missing data and multiple imputation in clinical epidemiological research.

    PubMed

    Pedersen, Alma B; Mikkelsen, Ellen M; Cronin-Fenton, Deirdre; Kristensen, Nickolaj R; Pham, Tra My; Pedersen, Lars; Petersen, Irene

    2017-01-01

    Missing data are ubiquitous in clinical epidemiological research. Individuals with missing data may differ from those with no missing data in terms of the outcome of interest and prognosis in general. Missing data are often categorized into the following three types: missing completely at random (MCAR), missing at random (MAR), and missing not at random (MNAR). In clinical epidemiological research, missing data are seldom MCAR. Missing data can constitute considerable challenges in the analyses and interpretation of results and can potentially weaken the validity of results and conclusions. A number of methods have been developed for dealing with missing data. These include complete-case analyses, missing indicator method, single value imputation, and sensitivity analyses incorporating worst-case and best-case scenarios. If applied under the MCAR assumption, some of these methods can provide unbiased but often less precise estimates. Multiple imputation is an alternative method to deal with missing data, which accounts for the uncertainty associated with missing data. Multiple imputation is implemented in most statistical software under the MAR assumption and provides unbiased and valid estimates of associations based on information from the available data. The method affects not only the coefficient estimates for variables with missing data but also the estimates for other variables with no missing data.

  11. Missing data and multiple imputation in clinical epidemiological research

    PubMed Central

    Pedersen, Alma B; Mikkelsen, Ellen M; Cronin-Fenton, Deirdre; Kristensen, Nickolaj R; Pham, Tra My; Pedersen, Lars; Petersen, Irene

    2017-01-01

    Missing data are ubiquitous in clinical epidemiological research. Individuals with missing data may differ from those with no missing data in terms of the outcome of interest and prognosis in general. Missing data are often categorized into the following three types: missing completely at random (MCAR), missing at random (MAR), and missing not at random (MNAR). In clinical epidemiological research, missing data are seldom MCAR. Missing data can constitute considerable challenges in the analyses and interpretation of results and can potentially weaken the validity of results and conclusions. A number of methods have been developed for dealing with missing data. These include complete-case analyses, missing indicator method, single value imputation, and sensitivity analyses incorporating worst-case and best-case scenarios. If applied under the MCAR assumption, some of these methods can provide unbiased but often less precise estimates. Multiple imputation is an alternative method to deal with missing data, which accounts for the uncertainty associated with missing data. Multiple imputation is implemented in most statistical software under the MAR assumption and provides unbiased and valid estimates of associations based on information from the available data. The method affects not only the coefficient estimates for variables with missing data but also the estimates for other variables with no missing data. PMID:28352203

  12. Learning from Non-Reported Data: Interpreting Missing Body Mass Index Values in Young Children

    ERIC Educational Resources Information Center

    Arbour-Nicitopoulos, Kelly P.; Faulkner, Guy E.; Leatherdale, Scott T.

    2010-01-01

    The objective of this study was to examine the pattern of relations between missing weight and height (BMI) data and a range of demographic, physical activity, sedentary behavior, and academic measures in a young sample of elementary school children. A secondary analysis of a large cross-sectional study, PLAY-On, was conducted using self-reported…

  13. Inverse-Probability-Weighted Estimation for Monotone and Nonmonotone Missing Data.

    PubMed

    Sun, BaoLuo; Perkins, Neil J; Cole, Stephen R; Harel, Ofer; Mitchell, Emily M; Schisterman, Enrique F; Tchetgen Tchetgen, Eric J

    2018-03-01

    Missing data is a common occurrence in epidemiologic research. In this paper, 3 data sets with induced missing values from the Collaborative Perinatal Project, a multisite US study conducted from 1959 to 1974, are provided as examples of prototypical epidemiologic studies with missing data. Our goal was to estimate the association of maternal smoking behavior with spontaneous abortion while adjusting for numerous confounders. At the same time, we did not necessarily wish to evaluate the joint distribution among potentially unobserved covariates, which is seldom the subject of substantive scientific interest. The inverse probability weighting (IPW) approach preserves the semiparametric structure of the underlying model of substantive interest and clearly separates the model of substantive interest from the model used to account for the missing data. However, IPW often will not result in valid inference if the missing-data pattern is nonmonotone, even if the data are missing at random. We describe a recently proposed approach to modeling nonmonotone missing-data mechanisms under missingness at random to use in constructing the weights in IPW complete-case estimation, and we illustrate the approach using 3 data sets described in a companion article (Am J Epidemiol. 2018;187(3):568-575).

  14. Inverse-Probability-Weighted Estimation for Monotone and Nonmonotone Missing Data

    PubMed Central

    Sun, BaoLuo; Perkins, Neil J; Cole, Stephen R; Harel, Ofer; Mitchell, Emily M; Schisterman, Enrique F; Tchetgen Tchetgen, Eric J

    2018-01-01

    Abstract Missing data is a common occurrence in epidemiologic research. In this paper, 3 data sets with induced missing values from the Collaborative Perinatal Project, a multisite US study conducted from 1959 to 1974, are provided as examples of prototypical epidemiologic studies with missing data. Our goal was to estimate the association of maternal smoking behavior with spontaneous abortion while adjusting for numerous confounders. At the same time, we did not necessarily wish to evaluate the joint distribution among potentially unobserved covariates, which is seldom the subject of substantive scientific interest. The inverse probability weighting (IPW) approach preserves the semiparametric structure of the underlying model of substantive interest and clearly separates the model of substantive interest from the model used to account for the missing data. However, IPW often will not result in valid inference if the missing-data pattern is nonmonotone, even if the data are missing at random. We describe a recently proposed approach to modeling nonmonotone missing-data mechanisms under missingness at random to use in constructing the weights in IPW complete-case estimation, and we illustrate the approach using 3 data sets described in a companion article (Am J Epidemiol. 2018;187(3):568–575). PMID:29165557

  15. A Spatiotemporal Prediction Framework for Air Pollution Based on Deep RNN

    NASA Astrophysics Data System (ADS)

    Fan, J.; Li, Q.; Hou, J.; Feng, X.; Karimian, H.; Lin, S.

    2017-10-01

    Time series data in practical applications always contain missing values due to sensor malfunction, network failure, outliers etc. In order to handle missing values in time series, as well as the lack of considering temporal properties in machine learning models, we propose a spatiotemporal prediction framework based on missing value processing algorithms and deep recurrent neural network (DRNN). By using missing tag and missing interval to represent time series patterns, we implement three different missing value fixing algorithms, which are further incorporated into deep neural network that consists of LSTM (Long Short-term Memory) layers and fully connected layers. Real-world air quality and meteorological datasets (Jingjinji area, China) are used for model training and testing. Deep feed forward neural networks (DFNN) and gradient boosting decision trees (GBDT) are trained as baseline models against the proposed DRNN. Performances of three missing value fixing algorithms, as well as different machine learning models are evaluated and analysed. Experiments show that the proposed DRNN framework outperforms both DFNN and GBDT, therefore validating the capacity of the proposed framework. Our results also provides useful insights for better understanding of different strategies that handle missing values.

  16. The HCUP SID Imputation Project: Improving Statistical Inferences for Health Disparities Research by Imputing Missing Race Data.

    PubMed

    Ma, Yan; Zhang, Wei; Lyman, Stephen; Huang, Yihe

    2018-06-01

    To identify the most appropriate imputation method for missing data in the HCUP State Inpatient Databases (SID) and assess the impact of different missing data methods on racial disparities research. HCUP SID. A novel simulation study compared four imputation methods (random draw, hot deck, joint multiple imputation [MI], conditional MI) for missing values for multiple variables, including race, gender, admission source, median household income, and total charges. The simulation was built on real data from the SID to retain their hierarchical data structures and missing data patterns. Additional predictive information from the U.S. Census and American Hospital Association (AHA) database was incorporated into the imputation. Conditional MI prediction was equivalent or superior to the best performing alternatives for all missing data structures and substantially outperformed each of the alternatives in various scenarios. Conditional MI substantially improved statistical inferences for racial health disparities research with the SID. © Health Research and Educational Trust.

  17. Cyclists' Anger As Determinant of Near Misses Involving Different Road Users.

    PubMed

    Marín Puchades, Víctor; Prati, Gabriele; Rondinella, Gianni; De Angelis, Marco; Fassina, Filippo; Fraboni, Federico; Pietrantoni, Luca

    2017-01-01

    Road anger constitutes one of the determinant factors related to safety outcomes (e.g., accidents, near misses). Although cyclists are considered vulnerable road users due to their relatively high rate of fatalities in traffic, previous research has solely focused on car drivers, and no study has yet investigated the effect of anger on cyclists' safety outcomes. The present research aims to investigate, for the first time, the effects of cycling anger toward different types of road users on near misses involving such road users and near misses in general. Using a daily diary web-based questionnaire, we collected data about daily trips, bicycle use, near misses experienced, cyclist's anger and demographic information from 254 Spanish cyclists. Poisson regression was used to assess the association of cycling anger with near misses, which is a count variable. No relationship was found between general cycling anger and near misses occurrence. Anger toward specific road users had different effects on the probability of near misses with different road users. Anger toward the interaction with car drivers increased the probability of near misses involving cyclists and pedestrians. Anger toward interaction with pedestrians was associated with higher probability of near misses with pedestrians. Anger toward cyclists exerted no effect on the probability of near misses with any road user (i.e., car drivers, cyclists or pedestrians), whereas anger toward the interactions with the police had a diminishing effect on the occurrence of near misses' involving all types of road users. The present study demonstrated that the effect of road anger on safety outcomes among cyclists is different from that of motorists. Moreover, the target of anger played an important role on safety both for the cyclist and the specific road users. Possible explanations for these differences are based on the difference in status and power with motorists, as well as on the potential displaced aggression produced by the fear of retaliation by motorized vehicle users.

  18. Self-organizing systems in planetary physics: Harmonic resonances of planet and moon orbits

    NASA Astrophysics Data System (ADS)

    Aschwanden, Markus J.

    2018-01-01

    The geometric arrangement of planet and moon orbits into a regularly spaced pattern of distances is the result of a self-organizing system. The positive feedback mechanism that operates a self-organizing system is accomplished by harmonic orbit resonances, leading to long-term stable planet and moon orbits in solar or stellar systems. The distance pattern of planets was originally described by the empirical Titius-Bode law, and by a generalized version with a constant geometric progression factor (corresponding to logarithmic spacing). We find that the orbital periods Ti and planet distances Ri from the Sun are not consistent with logarithmic spacing, but rather follow the quantized scaling (Ri + 1 /Ri) =(Ti + 1 /Ti) 2 / 3 =(Hi + 1 /Hi) 2 / 3 , where the harmonic ratios are given by five dominant resonances, namely (Hi + 1 :Hi) =(3 : 2) ,(5 : 3) ,(2 : 1) ,(5 : 2) ,(3 : 1) . We find that the orbital period ratios tend to follow the quantized harmonic ratios in increasing order. We apply this harmonic orbit resonance model to the planets and moons in our solar system, and to the exo-planets of 55 Cnc and HD 10180 planetary systems. The model allows us a prediction of missing planets in each planetary system, based on the quasi-regular self-organizing pattern of harmonic orbit resonance zones. We predict 7 (and 4) missing exo-planets around the star 55 Cnc (and HD 10180). The accuracy of the predicted planet and moon distances amounts to a few percents. All analyzed systems are found to have ≈ 10 resonant zones that can be occupied with planets (or moons) in long-term stable orbits.

  19. A structured framework for assessing sensitivity to missing data assumptions in longitudinal clinical trials.

    PubMed

    Mallinckrodt, C H; Lin, Q; Molenberghs, M

    2013-01-01

    The objective of this research was to demonstrate a framework for drawing inference from sensitivity analyses of incomplete longitudinal clinical trial data via a re-analysis of data from a confirmatory clinical trial in depression. A likelihood-based approach that assumed missing at random (MAR) was the primary analysis. Robustness to departure from MAR was assessed by comparing the primary result to those from a series of analyses that employed varying missing not at random (MNAR) assumptions (selection models, pattern mixture models and shared parameter models) and to MAR methods that used inclusive models. The key sensitivity analysis used multiple imputation assuming that after dropout the trajectory of drug-treated patients was that of placebo treated patients with a similar outcome history (placebo multiple imputation). This result was used as the worst reasonable case to define the lower limit of plausible values for the treatment contrast. The endpoint contrast from the primary analysis was - 2.79 (p = .013). In placebo multiple imputation, the result was - 2.17. Results from the other sensitivity analyses ranged from - 2.21 to - 3.87 and were symmetrically distributed around the primary result. Hence, no clear evidence of bias from missing not at random data was found. In the worst reasonable case scenario, the treatment effect was 80% of the magnitude of the primary result. Therefore, it was concluded that a treatment effect existed. The structured sensitivity framework of using a worst reasonable case result based on a controlled imputation approach with transparent and debatable assumptions supplemented a series of plausible alternative models under varying assumptions was useful in this specific situation and holds promise as a generally useful framework. Copyright © 2012 John Wiley & Sons, Ltd.

  20. Missed Lesions at CT Colonography: Lessons Learned

    PubMed Central

    Pickhardt, Perry J.

    2017-01-01

    Misinterpretation at CT colonography (CTC) can result in either a colorectal lesion being missed (false negative) or a false-positive diagnosis. This review will largely focus on potential missed lesions – and ways to avoid such misses. The general causes of false-negative interpretation at CTC can be broadly characterized and grouped into discrete categories related to suboptimal study technique, specific lesion characteristics, anatomic location, and imaging artifacts. Overlapping causes further increase the likelihood of missing a clinically relevant lesion. In the end, if the technical factors of bowel preparation, colonic distention, and robust CTC software are adequately addressed on a consistent basis, and the reader is aware of all the potential pitfalls at CTC, important lesions will seldom be missed. PMID:22539045

  1. Statistical primer: how to deal with missing data in scientific research?

    PubMed

    Papageorgiou, Grigorios; Grant, Stuart W; Takkenberg, Johanna J M; Mokhles, Mostafa M

    2018-05-10

    Missing data are a common challenge encountered in research which can compromise the results of statistical inference when not handled appropriately. This paper aims to introduce basic concepts of missing data to a non-statistical audience, list and compare some of the most popular approaches for handling missing data in practice and provide guidelines and recommendations for dealing with and reporting missing data in scientific research. Complete case analysis and single imputation are simple approaches for handling missing data and are popular in practice, however, in most cases they are not guaranteed to provide valid inferences. Multiple imputation is a robust and general alternative which is appropriate for data missing at random, surpassing the disadvantages of the simpler approaches, but should always be conducted with care. The aforementioned approaches are illustrated and compared in an example application using Cox regression.

  2. Methamphetamine Users Have Increased Dental Disease: A Propensity Score Analysis.

    PubMed

    Shetty, V; Harrell, L; Clague, J; Murphy, D A; Dye, B A; Belin, T R

    2016-07-01

    Methamphetamine (MA) users are assumed to have a high burden of tooth decay. Less clear is how the distribution and severity of dental caries in MA users differ from the general population. Using a covariate-balancing propensity score strategy, we investigated the differential effects of MA use on dental caries by comparing the patterns of decayed, missing, and filled teeth in a community sample of 571 MA users with a subset of 2,755 demographically similar control individuals selected from a National Health and Nutrition Examination Survey (NHANES) cohort. Recruited over a 2-y period with a stratified sampling protocol, the MA users underwent comprehensive dental examinations by 3 trained and calibrated dentists using NHANES protocols. Propensity scores were estimated with logistic regression based on background characteristics, and a subset of closely matched subjects was stratified into quintiles for comparisons. MA users were twice as likely to have untreated caries (odds ratio [OR] = 2.08; 95% confidence interval [95% CI]: 1.55 to 2.78) and 4 times more likely to have caries experience (OR = 4.06; 95% CI: 2.24 to 7.34) than the control group of NHANES participants. Additionally, MA users were twice as likely to have 2 more decayed, missing, or filled teeth (OR = 2.08; 95% CI: 1.29 to 2.79) than the NHANES participants. The differential involvement of the teeth surfaces in MA users was quite distinctive, with carious surface involvement being highest for the maxillary central incisors, followed by maxillary posterior premolars and molars. Users injecting MA had significantly higher rates of tooth decay compared with noninjectors (P = 0.04). Although MA users experienced decayed and missing dental surfaces more frequently than NHANES participants, NHANES participants had more restored surfaces, especially on molars. The high rates and distinctive patterns of dental caries observed could be used 1) to alert dentists to covert MA use in their patients and 2) as the basis for comprehensive management strategies. © International & American Associations for Dental Research 2016.

  3. Near Misses in Slot Machine Gambling Developed Through Generalization of Total Wins.

    PubMed

    Belisle, Jordan; Dixon, Mark R

    2016-06-01

    The purpose of the present study was to evaluate the development of the near miss effect in slot machine gambling as a product of stimulus generalization from total wins. The study was conducted across two experiments. Twelve college students participated in the first experiment, which demonstrated that greater post-reinforcement pauses followed losing outcomes that were formally similar to total wins, relative to losing outcomes that were formally dissimilar [F (5, 7) = 5.24, p = .025] along a generalization gradient (R (2) = .96). Additionally, 11 out of 12 participants showed greater response latencies following near-misses than following total wins. Thirteen college students participated in the second experiment, which demonstrated that symbols that more saliently indicated a loss resulted in lower response latencies than functionally equivalent but visually dissimilar losing symbols [F (3, 10) = 15.50, p = .01]. A generalization gradient was observed across winning symbols (R (2) = .98), and an inverse of the gradient observed across winning symbols was observed across symbols that were the least formally similar (R (2) = .69). The present study replicates and extends previous research on near misses in slot machine gambling, and provides discussion around the clinical utility of such findings on the prevention of problem gambling.

  4. A Novel Higher Order Artificial Neural Networks

    NASA Astrophysics Data System (ADS)

    Xu, Shuxiang

    2010-05-01

    In this paper a new Higher Order Neural Network (HONN) model is introduced and applied in several data mining tasks. Data Mining extracts hidden patterns and valuable information from large databases. A hyperbolic tangent function is used as the neuron activation function for the new HONN model. Experiments are conducted to demonstrate the advantages and disadvantages of the new HONN model, when compared with several conventional Artificial Neural Network (ANN) models: Feedforward ANN with the sigmoid activation function; Feedforward ANN with the hyperbolic tangent activation function; and Radial Basis Function (RBF) ANN with the Gaussian activation function. The experimental results seem to suggest that the new HONN holds higher generalization capability as well as abilities in handling missing data.

  5. For whom the bell tolls: Silver Alerts raise concerns regarding individual rights and governmental interests.

    PubMed

    Wasser, Tobias D; Fox, Patrick K

    2013-01-01

    The Silver Alert system was initially created to help protect missing persons who have cognitive impairments, particularly the elderly. The Silver Alert is modeled after the Amber Alert, created to help locate and safeguard missing children. Unlike the Amber Alert, however, in most states the Silver Alert applies to the elderly, adults with a mental impairment, or both, depending on the state. The goal of the Silver Alert system is the quick dissemination of information about missing persons to law enforcement personnel as well as to the general public. Previously, states notified law enforcement personnel of missing persons through teletype to other public safety jurisdictions to enlist their assistance in the retrieval of the missing person. Silver Alert programs substantially expand the notification to include the general public, who receive information through radio and television broadcasts as well as highway billboards. The programs serve a legitimate governmental interest by protecting a vulnerable population from possible harm. Yet, the implementation of these alerts can have unintended consequences, including the possible violation of an individual's right to privacy. Such consequences require careful consideration.

  6. How consistent are precipitation patterns predicted by GCMs in the absence of cloud radiative effects?

    NASA Astrophysics Data System (ADS)

    Popke, Dagmar; Bony, Sandrine; Mauritsen, Thorsten; Stevens, Bjorn

    2015-04-01

    Model simulations with state-of-the-art general circulation models reveal a strong disagreement concerning the simulated regional precipitation patterns and their changes with warming. The deviating precipitation response even persists when reducing the model experiment complexity to aquaplanet simulation with forced sea surface temperatures (Stevens and Bony, 2013). To assess feedbacks between clouds and radiation on precipitation responses we analyze data from 5 models performing the aquaplanet simulations of the Clouds On Off Klima Intercomparison Experiment (COOKIE), where the interaction of clouds and radiation is inhibited. Although cloud radiative effects are then disabled, the precipitation patterns among models are as diverse as with cloud radiative effects switched on. Disentangling differing model responses in such simplified experiments thus appears to be key to better understanding the simulated regional precipitation in more standard configurations. By analyzing the local moisture and moist static energy budgets in the COOKIE experiments we investigate likely causes for the disagreement among models. References Stevens, B. & S. Bony: What Are Climate Models Missing?, Science, 2013, 340, 1053-1054

  7. Associations of erythrocyte fatty acid patterns with insulin resistance

    USDA-ARS?s Scientific Manuscript database

    Background: Synergistic and/or additive effects on cardiometabolic risk may be missed by examining individual fatty acids (FA). A pattern analysis may be a more useful approach. As well, it remains unclear whether erythrocyte fatty acid composition relates to insulin resistance among Hispanic/Latino...

  8. Prospective Measurement of Daily Health Behaviors: Modeling Temporal Patterns in Missing Data, Sexual Behavior, and Substance Use in an Online Daily Diary Study of Gay and Bisexual Men.

    PubMed

    Rendina, H Jonathon; Ventuneac, Ana; Mustanski, Brian; Grov, Christian; Parsons, Jeffrey T

    2016-08-01

    Daily diary and other intensive longitudinal methods are increasingly being used to investigate fluctuations in psychological and behavioral processes. To inform the development of this methodology, we sought to explore predictors of and patterns in diary compliance and behavioral reports. We used multilevel modeling to analyze data from an online daily diary study of 371 gay and bisexual men focused on sexual behavior and substance use. We found that greater education and older age as well as lower frequency of substance use were associated with higher compliance. Using polynomial and trigonometric functions, we found evidence for circaseptan patterns in compliance, sexual behavior, and substance use, as well as linear declines in compliance and behavior over time. The results suggest potential sources of non-random patterns of missing data and suggest that trigonometric terms provide a similar but more parsimonious investigation of circaseptan rhythms than do third-order polynomial terms.

  9. Prospective Measurement of Daily Health Behaviors: Modeling Temporal Patterns in Missing Data, Sexual Behavior, and Substance Use in an Online Daily Diary Study of Gay and Bisexual Men

    PubMed Central

    Rendina, H. Jonathon; Ventuneac, Ana; Mustanski, Brian; Grov, Christian; Parsons, Jeffrey T.

    2016-01-01

    Daily diary and other intensive longitudinal methods are increasingly being used to investigate fluctuations in psychological and behavioral processes. To inform the development of this methodology, we sought to explore predictors of and patterns in diary compliance and behavioral reports. We used multilevel modeling to analyze data from an online daily diary study of 371 gay and bisexual men focused on sexual behavior and substance use. We found that greater education and older age as well as lower frequency of substance use were associated with higher compliance. Using polynomial and trigonometric functions, we found evidence for circaseptan patterns in compliance, sexual behavior, and substance use, as well as linear declines in compliance and behavior over time. The results suggest potential sources of non-random patterns of missing data and suggest that trigonometric terms provide a similar but more parsimonious investigation of circaseptan rhythms than do third-order polynomial terms. PMID:26992392

  10. Hierarchical imputation of systematically and sporadically missing data: An approximate Bayesian approach using chained equations.

    PubMed

    Jolani, Shahab

    2018-03-01

    In health and medical sciences, multiple imputation (MI) is now becoming popular to obtain valid inferences in the presence of missing data. However, MI of clustered data such as multicenter studies and individual participant data meta-analysis requires advanced imputation routines that preserve the hierarchical structure of data. In clustered data, a specific challenge is the presence of systematically missing data, when a variable is completely missing in some clusters, and sporadically missing data, when it is partly missing in some clusters. Unfortunately, little is known about how to perform MI when both types of missing data occur simultaneously. We develop a new class of hierarchical imputation approach based on chained equations methodology that simultaneously imputes systematically and sporadically missing data while allowing for arbitrary patterns of missingness among them. Here, we use a random effect imputation model and adopt a simplification over fully Bayesian techniques such as Gibbs sampler to directly obtain draws of parameters within each step of the chained equations. We justify through theoretical arguments and extensive simulation studies that the proposed imputation methodology has good statistical properties in terms of bias and coverage rates of parameter estimates. An illustration is given in a case study with eight individual participant datasets. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. The competing risks Cox model with auxiliary case covariates under weaker missing-at-random cause of failure.

    PubMed

    Nevo, Daniel; Nishihara, Reiko; Ogino, Shuji; Wang, Molin

    2017-08-04

    In the analysis of time-to-event data with multiple causes using a competing risks Cox model, often the cause of failure is unknown for some of the cases. The probability of a missing cause is typically assumed to be independent of the cause given the time of the event and covariates measured before the event occurred. In practice, however, the underlying missing-at-random assumption does not necessarily hold. Motivated by colorectal cancer molecular pathological epidemiology analysis, we develop a method to conduct valid analysis when additional auxiliary variables are available for cases only. We consider a weaker missing-at-random assumption, with missing pattern depending on the observed quantities, which include the auxiliary covariates. We use an informative likelihood approach that will yield consistent estimates even when the underlying model for missing cause of failure is misspecified. The superiority of our method over naive methods in finite samples is demonstrated by simulation study results. We illustrate the use of our method in an analysis of colorectal cancer data from the Nurses' Health Study cohort, where, apparently, the traditional missing-at-random assumption fails to hold.

  12. Miss School and Miss Out: Taking on Truancy. A Legal Memorandum: Quarterly Law Topics for School Leaders. Vol. 7, No. 4, Summer 2007

    ERIC Educational Resources Information Center

    Kirby, Elizabeth

    2007-01-01

    The importance of school attendance in relation to achievement, engagement, and educational success has been well researched and documented. As a result, the general philosophy is that the more time students are in school, the better chance they have to be personally and academically successful. Students miss school for myriad reasons. While some…

  13. What impact do assumptions about missing data have on conclusions? A practical sensitivity analysis for a cancer survival registry.

    PubMed

    Smuk, M; Carpenter, J R; Morris, T P

    2017-02-06

    Within epidemiological and clinical research, missing data are a common issue and often over looked in publications. When the issue of missing observations is addressed it is usually assumed that the missing data are 'missing at random' (MAR). This assumption should be checked for plausibility, however it is untestable, thus inferences should be assessed for robustness to departures from missing at random. We highlight the method of pattern mixture sensitivity analysis after multiple imputation using colorectal cancer data as an example. We focus on the Dukes' stage variable which has the highest proportion of missing observations. First, we find the probability of being in each Dukes' stage given the MAR imputed dataset. We use these probabilities in a questionnaire to elicit prior beliefs from experts on what they believe the probability would be in the missing data. The questionnaire responses are then used in a Dirichlet draw to create a Bayesian 'missing not at random' (MNAR) prior to impute the missing observations. The model of interest is applied and inferences are compared to those from the MAR imputed data. The inferences were largely insensitive to departure from MAR. Inferences under MNAR suggested a smaller association between Dukes' stage and death, though the association remained positive and with similarly low p values. We conclude by discussing the positives and negatives of our method and highlight the importance of making people aware of the need to test the MAR assumption.

  14. Missed rib fractures on evaluation of initial chest CT for trauma patients: pattern analysis and diagnostic value of coronal multiplanar reconstruction images with multidetector row CT.

    PubMed

    Cho, S H; Sung, Y M; Kim, M S

    2012-10-01

    The objective of this study was to review the prevalence and radiological features of rib fractures missed on initial chest CT evaluation, and to examine the diagnostic value of additional coronal images in a large series of trauma patients. 130 patients who presented to an emergency room for blunt chest trauma underwent multidetector row CT of the thorax within the first hour during their stay, and had follow-up CT or bone scans as diagnostic gold standards. Images were evaluated on two separate occasions: once with axial images and once with both axial and coronal images. The detection rates of missed rib fractures were compared between readings using a non-parametric method of clustered data. In the cases of missed rib fractures, the shapes, locations and associated fractures were evaluated. 58 rib fractures were missed with axial images only and 52 were missed with both axial and coronal images (p=0.088). The most common shape of missed rib fractures was buckled (56.9%), and the anterior arc (55.2%) was most commonly involved. 21 (36.2%) missed rib fractures had combined fractures on the same ribs, and 38 (65.5%) were accompanied by fracture on neighbouring ribs. Missed rib fractures are not uncommon, and radiologists should be familiar with buckle fractures, which are frequently missed. Additional coronal imagescan be helpful in the diagnosis of rib fractures that are not seen on axial images.

  15. Spatial Patterns in Alternative States and Thresholds: A Missing Link for Management of Landscapes?

    USDA-ARS?s Scientific Manuscript database

    The detection of threshold dynamics (and other dynamics of interest) would benefit from explicit representations of spatial patterns of disturbance, spatial dependence in responses to disturbance, and the spatial structure of feedbacks in the design of monitoring and management strategies. Spatially...

  16. Anthropometric analysis of waist-to-hip ratio in Asian women.

    PubMed

    Hong, Young Jun; Park, Heung Sik; Lee, Eun Sang; Suh, Young Ju

    2009-03-01

    The universally accepted attractive female figure has a waist-to-hip ratio (WHR) of 0.7 or 0.68 (WHR of the Venus de Milo). Using WHR and other parameters, the authors attempted to investigate chronologic changes in perceptions of the attractive female figure in Korean society, differences between Asian and Western societies in this respect, and changes in attractiveness with respect to body mass index (BMI) and age in the general female Korean population. The authors analyzed the anthropometric measurements of 227 Miss Korea winners between 1971 and 2007, 60 candidates of the 2007 Miss Korea contest, 36 candidates of the 2007 Miss France contest, and 1785 normal women in the general population. In the Miss Korea winners' group, the WHR tended toward 0.7. The WHR of the 2007 Miss Korea candidates was statistically smaller than the WHR of the 2007 Miss France candidates. The WHR of normal women was statistically larger than WHR of the 2000s Miss Korea winners. In all age groups of normal women, subjects with a low BMI were not significantly different from the 2000s Miss Koreas in terms of waist circumference, but they had a relatively larger hip circumference. Moreover, subjects with a normal BMI had waist circumferences that were similar to those of the 2000s Miss Koreas but relatively larger hip circumferences, and subjects with high BMI had larger waist and hip circumferences than the 2000s Miss Koreas. The perceived attractive female figure in Asia has moved toward the universally accepted ideal WHR. However, there were still some differences between Asian and Western societies in the concept of ideal body figure. Also, a significant difference in body contour was observed between normal women and the ideal figure. This is because hip volume decreases and waist volume increases with age, although waist and hip volumes increase with BMI.

  17. Prevalence of urinary tract infection in acutely unwell children in general practice: a prospective study with systematic urine sampling

    PubMed Central

    O’Brien, Kathryn; Edwards, Adrian; Hood, Kerenza; Butler, Christopher C

    2013-01-01

    Background Urinary tract infection (UTI) in children may be associated with long-term complications that could be prevented by prompt treatment. Aim To determine the prevalence of UTI in acutely ill children ≤ 5 years presenting in general practice and to explore patterns of presenting symptoms and urine sampling strategies. Design and setting Prospective observational study with systematic urine sampling, in general practices in Wales, UK. Method In total, 1003 children were recruited from 13 general practices between March 2008 and July 2010. The prevalence of UTI was determined and multivariable analysis performed to determine the probability of UTI. Result Out of 597 (60.0%) children who provided urine samples within 2 days, the prevalence of UTI was 5.9% (95% confidence interval [CI] = 4.3% to 8.0%) overall, 7.3% in those < 3 years and 3.2% in 3–5 year olds. Neither a history of fever nor the absence of an alternative source of infection was associated with UTI (P = 0.64; P = 0.69, respectively). The probability of UTI in children aged ≥3 years without increased urinary frequency or dysuria was 2%. The probability of UTI was ≥5% in all other groups. Urine sampling based purely on GP suspicion would have missed 80% of UTIs, while a sampling strategy based on current guidelines would have missed 50%. Conclusion Approximately 6% of acutely unwell children presenting to UK general practice met the criteria for a laboratory diagnosis of UTI. This higher than previously recognised prior probability of UTI warrants raised awareness of the condition and suggests clinicians should lower their threshold for urine sampling in young children. The absence of fever or presence of an alternative source of infection, as emphasised in current guidelines, may not rule out UTI in young children with adequate certainty. PMID:23561695

  18. Using generalized estimating equations and extensions in randomized trials with missing longitudinal patient reported outcome data.

    PubMed

    Bell, Melanie L; Horton, Nicholas J; Dhillon, Haryana M; Bray, Victoria J; Vardy, Janette

    2018-05-26

    Patient reported outcomes (PROs) are important in oncology research; however, missing data can pose a threat to the validity of results. Psycho-oncology researchers should be aware of the statistical options for handling missing data robustly. One rarely used set of methods, which includes extensions for handling missing data, is generalized estimating equations (GEEs). Our objective was to demonstrate use of GEEs to analyze PROs with missing data in randomized trials with assessments at fixed time points. We introduce GEEs and show, with a worked example, how to use GEEs that account for missing data: inverse probability weighted GEEs and multiple imputation with GEE. We use data from an RCT evaluating a web-based brain training for cancer survivors reporting cognitive symptoms after chemotherapy treatment. The primary outcome for this demonstration is the binary outcome of cognitive impairment. Several methods are used, and results are compared. We demonstrate that estimates can vary depending on the choice of analytical approach, with odds ratios for no cognitive impairment ranging from 2.04 to 5.74. While most of these estimates were statistically significant (P < 0.05), a few were not. Researchers using PROs should use statistical methods that handle missing data in a way as to result in unbiased estimates. GEE extensions are analytic options for handling dropouts in longitudinal RCTs, particularly if the outcome is not continuous. Copyright © 2018 John Wiley & Sons, Ltd.

  19. Structural Effects of Network Sampling Coverage I: Nodes Missing at Random1.

    PubMed

    Smith, Jeffrey A; Moody, James

    2013-10-01

    Network measures assume a census of a well-bounded population. This level of coverage is rarely achieved in practice, however, and we have only limited information on the robustness of network measures to incomplete coverage. This paper examines the effect of node-level missingness on 4 classes of network measures: centrality, centralization, topology and homophily across a diverse sample of 12 empirical networks. We use a Monte Carlo simulation process to generate data with known levels of missingness and compare the resulting network scores to their known starting values. As with past studies (Borgatti et al 2006; Kossinets 2006), we find that measurement bias generally increases with more missing data. The exact rate and nature of this increase, however, varies systematically across network measures. For example, betweenness and Bonacich centralization are quite sensitive to missing data while closeness and in-degree are robust. Similarly, while the tau statistic and distance are difficult to capture with missing data, transitivity shows little bias even with very high levels of missingness. The results are also clearly dependent on the features of the network. Larger, more centralized networks are generally more robust to missing data, but this is especially true for centrality and centralization measures. More cohesive networks are robust to missing data when measuring topological features but not when measuring centralization. Overall, the results suggest that missing data may have quite large or quite small effects on network measurement, depending on the type of network and the question being posed.

  20. Distal Fibula Fractures in National Football League Athletes.

    PubMed

    Werner, Brian C; Mack, Christina; Franke, Kristina; Barnes, Ronnie P; Warren, Russell F; Rodeo, Scott A

    2017-09-01

    Despite the frequency of distal fibula fractures in elite athletes and the significant potential impact on the athletes' season and future careers, little data exist characterizing the epidemiology of these injuries or, more importantly, return to competition. To (1) evaluate the incidence of acute distal fibula fractures in National Football League (NFL) athletes, including isolated distal fibula and combined ankle fracture patterns; (2) analyze distal fibula fracture rates in NFL athletes by position, type of play, and contact type; (3) determine the rates of distal fibula fracture surgery in NFL athletes; and (4) report the days missed due to distal fibula fractures in NFL athletes. Descriptive epidemiology study. A retrospective review of distal fibula fractures reported to the NFL from 2000 to 2014 was performed using the NFL Injury Surveillance System. All distal fibula fractures were included, along with isolated and combined fracture patterns. Stress fractures and proximal fibula fractures were excluded. Epidemiological data and rates of surgery were determined. Return to sport was calculated and stratified by injury pattern and management. Overall, 237 distal fibula fractures in NFL athletes from 2000 to 2014 were included; 197 (83%) were isolated distal fibula fractures. A mean of 16 distal fibula fractures occurred each year (median, 16 per year). Fractures occurred most frequently on running (38%) and passing (24%) plays, but the frequency was next highest on kickoffs (16%), despite the relative infrequency of kickoffs during the average game compared with other play types. Surgery was reported for more than half of all distal fibula fractures (n = 128, 54%). Overall, patients who underwent surgery missed significantly more days (mean, 123.8 days) than players who did not undergo surgery (mean, 75.3 days) ( P < .001). Players with isolated distal fibula fractures had significantly fewer days missed (mean, 93.6 days) compared with those with combined patterns (mean, 132.3 days) ( P = .0004). Fibula fractures affect a number of NFL athletes and result in significant time missed from competition. Further research is required to determine the optimal management of fibula fractures in NFL athletes. In this study, time to return to play depended on both the fracture pattern and whether surgery was required and ranged from 72 to 145 days.

  1. Opportunities to diagnose chronic obstructive pulmonary disease in routine care in the UK: a retrospective study of a clinical cohort.

    PubMed

    Jones, Rupert C M; Price, David; Ryan, Dermot; Sims, Erika J; von Ziegenweidt, Julie; Mascarenhas, Laurence; Burden, Anne; Halpin, David M G; Winter, Robert; Hill, Sue; Kearney, Matt; Holton, Kevin; Moger, Anne; Freeman, Daryl; Chisholm, Alison; Bateman, Eric D

    2014-04-01

    Patterns of health-care use and comorbidities present in patients in the period before diagnosis of chronic obstructive pulmonary disease (COPD) are unknown. We investigated these factors to inform future case-finding strategies. We did a retrospective analysis of a clinical cohort in the UK with data from Jan 1, 1990 to Dec 31, 2009 (General Practice Research Database and Optimum Patient Care Research Database). We assessed patients aged 40 years or older who had an electronically coded diagnosis of COPD in their primary care records and had a minimum of 3 years of continuous practice data for COPD (2 years before diagnosis up to a maximum of 20 years, and 1 year after diagnosis) and at least two prescriptions for COPD since diagnosis. We identified missed opportunites to diagnose COPD from routinely collected patient data by reviewing patterns of health-care use and comorbidities present before diagnosis. We assessed patterns of health-care use in terms of lower respiratory consultations (infective and non-infective), lower respiratory consultations with a course of antibiotics or oral steroids, and chest radiography. If these events did not lead to a diagnosis of COPD, they were deemed to be missed opportunities. This study is registered with ClinicalTrials.gov, number NCT01655667. We assessed data for 38,859 patients. Opportunities for diagnosis were missed in 32,900 (85%) of 38,859 patients in the 5 years immediately preceding diagnosis of COPD; in 12,856 (58%) of 22,286 in the 6-10 years before diagnosis, in 3943 (42%) of 9351 in the 11-15 years before diagnosis; and in 95 (8%) of 1167 in the 16-20 years before diagnosis. Between 1990 and 2009, we noted decreases in the age at diagnosis (0·05 years of age per year, 95% CI 0·03-0·07) and yearly frequency of lower respiratory prescribing consultations (rate ratio 0·982 opportunities per year, 95% CI 0·979-0·985). Prevalence of all comorbidities present at COPD diagnosis increased except for asthma and bronchiectasis, which decreased between 1990 and 2007, from 281 (33·4%) of 842 patients to 451 of 1465 (30·8%) for asthma, and from 53 of 842 (6·3%) to 53 of 1465 (3·6%) for bronchiectasis. In the 2 years before diagnosis, of 6897 patients who had had a chest radiography, only 2296 (33%) also had spirometry. Opportunities to diagnose COPD at an earlier stage are being missed, and could be improved by case-finding in patients with lower respiratory tract symptoms and concordant long-term comorbidities. UK Department of Health, Research in Real Life. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Spatial Copula Model for Imputing Traffic Flow Data from Remote Microwave Sensors.

    PubMed

    Ma, Xiaolei; Luan, Sen; Du, Bowen; Yu, Bin

    2017-09-21

    Issues of missing data have become increasingly serious with the rapid increase in usage of traffic sensors. Analyses of the Beijing ring expressway have showed that up to 50% of microwave sensors pose missing values. The imputation of missing traffic data must be urgently solved although a precise solution that cannot be easily achieved due to the significant number of missing portions. In this study, copula-based models are proposed for the spatial interpolation of traffic flow from remote traffic microwave sensors. Most existing interpolation methods only rely on covariance functions to depict spatial correlation and are unsuitable for coping with anomalies due to Gaussian consumption. Copula theory overcomes this issue and provides a connection between the correlation function and the marginal distribution function of traffic flow. To validate copula-based models, a comparison with three kriging methods is conducted. Results indicate that copula-based models outperform kriging methods, especially on roads with irregular traffic patterns. Copula-based models demonstrate significant potential to impute missing data in large-scale transportation networks.

  3. Clustering with Missing Values: No Imputation Required

    NASA Technical Reports Server (NTRS)

    Wagstaff, Kiri

    2004-01-01

    Clustering algorithms can identify groups in large data sets, such as star catalogs and hyperspectral images. In general, clustering methods cannot analyze items that have missing data values. Common solutions either fill in the missing values (imputation) or ignore the missing data (marginalization). Imputed values are treated as just as reliable as the truly observed data, but they are only as good as the assumptions used to create them. In contrast, we present a method for encoding partially observed features as a set of supplemental soft constraints and introduce the KSC algorithm, which incorporates constraints into the clustering process. In experiments on artificial data and data from the Sloan Digital Sky Survey, we show that soft constraints are an effective way to enable clustering with missing values.

  4. Testing Students with Special Educational Needs in Large-Scale Assessments – Psychometric Properties of Test Scores and Associations with Test Taking Behavior

    PubMed Central

    Pohl, Steffi; Südkamp, Anna; Hardt, Katinka; Carstensen, Claus H.; Weinert, Sabine

    2016-01-01

    Assessing competencies of students with special educational needs in learning (SEN-L) poses a challenge for large-scale assessments (LSAs). For students with SEN-L, the available competence tests may fail to yield test scores of high psychometric quality, which are—at the same time—measurement invariant to test scores of general education students. We investigated whether we can identify a subgroup of students with SEN-L, for which measurement invariant competence measures of adequate psychometric quality may be obtained with tests available in LSAs. We furthermore investigated whether differences in test-taking behavior may explain dissatisfying psychometric properties and measurement non-invariance of test scores within LSAs. We relied on person fit indices and mixture distribution models to identify students with SEN-L for whom test scores with satisfactory psychometric properties and measurement invariance may be obtained. We also captured differences in test-taking behavior related to guessing and missing responses. As a result we identified a subgroup of students with SEN-L for whom competence scores of adequate psychometric quality that are measurement invariant to those of general education students were obtained. Concerning test taking behavior, there was a small number of students who unsystematically picked response options. Removing these students from the sample slightly improved item fit. Furthermore, two different patterns of missing responses were identified that explain to some extent problems in the assessments of students with SEN-L. PMID:26941665

  5. Maternal near-miss: a multicenter surveillance in Kathmandu Valley.

    PubMed

    Rana, Ashma; Baral, Gehanath; Dangal, Ganesh

    2013-01-01

    Multicenter surveillance has been carried out on maternal near-miss in the hospitals with sentinel units. Near-miss is recognized as the predictor of level of care and maternal death. Reducing Maternal Mortality Ratio is one of the challenges to achieve Millennium Development Goal. The objective was to determine the frequency and the nature of near-miss events and to analyze the near-miss morbidities among pregnant women. A prospective surveillance was done for a year in 2012 at nine hospitals in Kathmandu valley. Cases eligible by definition were recorded as a census based on WHO near-miss guideline. Similar questionnaires and dummy tables were used to present the results by non-inferential statistics. Out of 157 cases identified with near-miss rate of 3.8 per 1000 live births, severe complications were postpartum hemorrhage 62 (40%) and preeclampsia-eclampsia 25 (17%). Blood transfusion 102 (65%), ICU admission 85 (54%) and surgery 53 (32%) were common critical interventions. Oxytocin was main uterotonic used both prophylactically and therapeutically at health facilities. Total of 30 (19%) cases arrived at health facility after delivery or abortion. MgSO4 was used in all cases of eclampsia. All laparotomies were performed within three hours of arrival. Near-miss to maternal death ratio was 6:1 and MMR was 62. Study result yielded similar pattern amongst developing countries and same near-miss conditions as the causes of maternal death reported by national statistics. Process indicators qualified the recommended standard of care. The near-miss event could be used as a surrogate marker of maternal death and a window for system level intervention.

  6. Missed rib fractures on evaluation of initial chest CT for trauma patients: pattern analysis and diagnostic value of coronal multiplanar reconstruction images with multidetector row CT

    PubMed Central

    Cho, S H; Sung, Y M; Kim, M S

    2012-01-01

    Objective The objective of this study was to review the prevalence and radiological features of rib fractures missed on initial chest CT evaluation, and to examine the diagnostic value of additional coronal images in a large series of trauma patients. Methods 130 patients who presented to an emergency room for blunt chest trauma underwent multidetector row CT of the thorax within the first hour during their stay, and had follow-up CT or bone scans as diagnostic gold standards. Images were evaluated on two separate occasions: once with axial images and once with both axial and coronal images. The detection rates of missed rib fractures were compared between readings using a non-parametric method of clustered data. In the cases of missed rib fractures, the shapes, locations and associated fractures were evaluated. Results 58 rib fractures were missed with axial images only and 52 were missed with both axial and coronal images (p=0.088). The most common shape of missed rib fractures was buckled (56.9%), and the anterior arc (55.2%) was most commonly involved. 21 (36.2%) missed rib fractures had combined fractures on the same ribs, and 38 (65.5%) were accompanied by fracture on neighbouring ribs. Conclusion Missed rib fractures are not uncommon, and radiologists should be familiar with buckle fractures, which are frequently missed. Additional coronal imagescan be helpful in the diagnosis of rib fractures that are not seen on axial images. PMID:22514102

  7. Rotaviral and bacterial gastroenteritis in children during winter: an evaluation of physician ordering patterns.

    PubMed

    Chemaly, Roy F; Yen-Lieberman, Belinda; Schindler, Sue A; Goldfarb, Johanna; Hall, Gerri S; Procop, Gary W

    2003-09-01

    Identification of the agents of infectious diarrhea may facilitate appropriate therapy and prevent inappropriate antibiotic use. To better define the etiology of infectious diarrhea for children <12 years in our community and to study the ordering patterns of physicians. We reviewed test results of stool specimens from children <12 years old at our institution (CCF) and those submitted through our reference laboratory for rotavirus enzyme immunoassay (REIA) and stool cultures for a 7-month period (11/1/00-6/1/01). For CCF patients, REIA and stool cultures for usual bacterial enteric pathogens (BEP) were performed, regardless of the test ordered (i.e. REIA alone, stool culture alone or both). We compared the results with the orders placed to determine if requests for rotavirus alone or bacterial stool culture alone missed BEP or rotavirus, respectively. Overall, REIAs were performed on 81% (538/661) of stool specimens, with 37% positive. Stool cultures were performed on 62% (408/661) of stool specimens, with 4.4% positive. Stool specimens (280) from CCF pediatric patients were evaluated for both rotavirus and BEP. Some 42% of REIA and 23% of stool cultures were ordered as single tests, while both tests were ordered for 35% of the patients. Of the REIA ordered alone, 34% were positive for rotavirus; however, 2.5% of these contained BEP that would have been missed. Of the stool cultures that were ordered alone, 8% were positive; however, 19% of these contained rotavirus that would have been missed. When both tests were ordered, 22% contained rotavirus and 2% contained BEP. Both rotavirus and bacterial enteric infections were missed with selective viral versus bacterial specific ordering patterns. A rotaviral screen prior to stool culture may be useful for children with diarrhea during the winter months.

  8. [Near miss outcomes in gambling games].

    PubMed

    Pecsenye, Zsuzsa; Kurucz, Gyozo

    2017-01-01

    Games of chance operate with an intermittent reinforcement schedule in which the number of games takes the player to win differ in each turn thus they can not predict when the next positive reinforcement arrives. The near miss outcome (close to winning but actually a losing outcome) can be interpreted as a secondary (built in) reinforcement within variable ratio reinforcement schedule that presumably contribute to the development and maintanance of gambling addiction. The aim of this publication would be to introduce near miss outcomes and to summarize and critically analyze literature connected to this issue.We searched internet datebases using word "near miss" and analyse articles focusing on gambling games. Based on numerous authors' results a near miss rate set at around 30% increases the desire to continue playing among gamblers and players who have no former gambling experience as well. Some studies have demonstrated that this effect might be related to the extent the player has the situation under control during the gambling session. The hypothetical inhibiting effect of a 45% near miss ratio has not yet been proven. Neurobiological researches show middle-cerebral activity during near miss outcomes furthermore similar physiological patterns have been discovered following a near miss and winning outcomes. Regarding the connection between intrapsychic variables (cognitive and personality factors) and near misses there are very few studies. The fact that different authors interpret near miss outcomes differently even when studying the same game leads to problems in interpreting their results. It follows from the foregoing empirical results that near miss outcomes contribute to the development and maintanance of pathological gambling but we have little information on the factors implementing this effect.

  9. Predictors of the frequency and subjective experience of cycling near misses: Findings from the first two years of the UK Near Miss Project.

    PubMed

    Aldred, Rachel; Goodman, Anna

    2018-01-01

    Using 2014 and 2015 data from the UK Near Miss Project, this paper examines the stability of self-report incident rates for cycling near misses across these two years. It further examines the stability of the individual-level predictors of experiencing a near miss, including what influences the scariness of an incident. The paper uses three questions asked for only in 2015, which allow further exploration of factors shaping near miss rates and impacts of incidents. Firstly, a respondent's level of cycling experience; secondly, whether an incident was perceived as deliberate; and finally, whether the respondent themselves described the incident as a 'near miss' (as opposed to only a frightening and/or annoying non-injury incident). Using this data, we find a decline of almost a third in incident rates in 2015 compared to 2014, which we believe is likely to be largely an artefact due to differences in reporting rates. This suggests caution about interpreting small fluctuations in subjectively reported near miss rates. However, in both years near miss rates are many times more frequent than injury collisions. In both years of data collection our findings are very similar in terms of the patterning of incident types, and how frightening different incident categories are, which increases confidence in these findings. We find that new cyclists experience very high incident rates compared to other cyclists, and test a conceptual model explaining how perceived deliberateness, near-miss status, and scariness are connected. For example, incidents that are perceived to be deliberate are more likely to be experienced as very frightening, independent of their 'near miss' status. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Impact of missing data strategies in studies of parental employment and health: Missing items, missing waves, and missing mothers.

    PubMed

    Nguyen, Cattram D; Strazdins, Lyndall; Nicholson, Jan M; Cooklin, Amanda R

    2018-07-01

    Understanding the long-term health effects of employment - a major social determinant - on population health is best understood via longitudinal cohort studies, yet missing data (attrition, item non-response) remain a ubiquitous challenge. Additionally, and unique to the work-family context, is the intermittent participation of parents, particularly mothers, in employment, yielding 'incomplete' data. Missing data are patterned by gender and social circumstances, and the extent and nature of resulting biases are unknown. This study investigates how estimates of the association between work-family conflict and mental health depend on the use of four different approaches to missing data treatment, each of which allows for progressive inclusion of more cases in the analyses. We used 5 waves of data from 4983 mothers participating in the Longitudinal Study of Australian Children. Only 23% had completely observed work-family conflict data across all waves. Participants with and without missing data differed such that complete cases were the most advantaged group. Comparison of the missing data treatments indicate the expected narrowing of confidence intervals when more sample were included. However, impact on the estimated strength of association varied by level of exposure: At the lower levels of work-family conflict, estimates strengthened (were larger); at higher levels they weakened (were smaller). Our results suggest that inadequate handling of missing data in extant longitudinal studies of work-family conflict and mental health may have misestimated the adverse effects of work-family conflict, particularly for mothers. Considerable caution should be exercised in interpreting analyses that fail to explore and account for biases arising from missing data. Copyright © 2018. Published by Elsevier Ltd.

  11. Identification and Validation of Human Missing Proteins and Peptides in Public Proteome Databases: Data Mining Strategy.

    PubMed

    Elguoshy, Amr; Hirao, Yoshitoshi; Xu, Bo; Saito, Suguru; Quadery, Ali F; Yamamoto, Keiko; Mitsui, Toshiaki; Yamamoto, Tadashi

    2017-12-01

    In an attempt to complete human proteome project (HPP), Chromosome-Centric Human Proteome Project (C-HPP) launched the journey of missing protein (MP) investigation in 2012. However, 2579 and 572 protein entries in the neXtProt (2017-1) are still considered as missing and uncertain proteins, respectively. Thus, in this study, we proposed a pipeline to analyze, identify, and validate human missing and uncertain proteins in open-access transcriptomics and proteomics databases. Analysis of RNA expression pattern for missing proteins in Human protein Atlas showed that 28% of them, such as Olfactory receptor 1I1 ( O60431 ), had no RNA expression, suggesting the necessity to consider uncommon tissues for transcriptomic and proteomic studies. Interestingly, 21% had elevated expression level in a particular tissue (tissue-enriched proteins), indicating the importance of targeting such proteins in their elevated tissues. Additionally, the analysis of RNA expression level for missing proteins showed that 95% had no or low expression level (0-10 transcripts per million), indicating that low abundance is one of the major obstacles facing the detection of missing proteins. Moreover, missing proteins are predicted to generate fewer predicted unique tryptic peptides than the identified proteins. Searching for these predicted unique tryptic peptides that correspond to missing and uncertain proteins in the experimental peptide list of open-access MS-based databases (PA, GPM) resulted in the detection of 402 missing and 19 uncertain proteins with at least two unique peptides (≥9 aa) at <(5 × 10 -4 )% FDR. Finally, matching the native spectra for the experimentally detected peptides with their SRMAtlas synthetic counterparts at three transition sources (QQQ, QTOF, QTRAP) gave us an opportunity to validate 41 missing proteins by ≥2 proteotypic peptides.

  12. Multiple imputation for multivariate data with missing and below-threshold measurements: time-series concentrations of pollutants in the Arctic.

    PubMed

    Hopke, P K; Liu, C; Rubin, D B

    2001-03-01

    Many chemical and environmental data sets are complicated by the existence of fully missing values or censored values known to lie below detection thresholds. For example, week-long samples of airborne particulate matter were obtained at Alert, NWT, Canada, between 1980 and 1991, where some of the concentrations of 24 particulate constituents were coarsened in the sense of being either fully missing or below detection limits. To facilitate scientific analysis, it is appealing to create complete data by filling in missing values so that standard complete-data methods can be applied. We briefly review commonly used strategies for handling missing values and focus on the multiple-imputation approach, which generally leads to valid inferences when faced with missing data. Three statistical models are developed for multiply imputing the missing values of airborne particulate matter. We expect that these models are useful for creating multiple imputations in a variety of incomplete multivariate time series data sets.

  13. Spacecraft intercept guidance using zero effort miss steering

    NASA Astrophysics Data System (ADS)

    Newman, Brett

    The suitability of proportional navigation, or an equivalent zero effort miss formulation, for spacecraft intercepts during midcourse guidance, followed by a ballistic coast to the endgame, is addressed. The problem is formulated in terms of relative motion in a general 3D framework. The proposed guidance law for the commanded thrust vector orientation consists of the sum of two terms: (1) along the line of sight unit direction and (2) along the zero effort miss component perpendicular to the line of sight and proportional to the miss itself and a guidance gain. If the guidance law is to be suitable for longer range targeting applications with significant ballistic coasting after burnout, determination of the zero effort miss must account for the different gravitational accelerations experienced by each vehicle. The proposed miss determination techniques employ approximations for the true differential gravity effect. Theoretical results are applied to a numerical engagement scenario and the resulting performance is evaluated in terms of the miss distances determined from nonlinear simulation.

  14. Missed doses of oral antihyperglycemic medications in US adults with type 2 diabetes mellitus: prevalence and self-reported reasons.

    PubMed

    Vietri, Jeffrey T; Wlodarczyk, Catherine S; Lorenzo, Rose; Rajpathak, Swapnil

    2016-09-01

    Adherence to antihyperglycemic medication is thought to be suboptimal, but the proportion of patients missing doses, the number of doses missed, and reasons for missing are not well described. This survey was conducted to estimate the prevalence of and reasons for missed doses of oral antihyperglycemic medications among US adults with type 2 diabetes mellitus, and to explore associations between missed doses and health outcomes. The study was a cross-sectional patient survey. Respondents were contacted via a commercial survey panel and completed an on-line questionnaire via the Internet. Respondents provided information about their use of oral antihyperglycemic medications including doses missed in the prior 4 weeks, personal characteristics, and health outcomes. Weights were calculated to project the prevalence to the US adult population with type 2 diabetes mellitus. Outcomes were compared according to number of doses missed in the past 4 weeks using bivariate statistics and generalized linear models. Approximately 30% of adult patients with type 2 diabetes mellitus reported missing or reducing ≥1 dose of oral antihyperglycemic medication in the prior 4 weeks. Accidental missing was more commonly reported than purposeful skipping, with forgetting the most commonly reported reason. The timing of missed doses suggested respondents had also forgotten about doses missed, so the prevalence of missed doses is likely higher than reported. Outcomes were poorer among those who reported missing three or more doses in the prior 4 weeks. A substantial number of US adults with type 2 diabetes mellitus miss doses of their oral antihyperglycemic medications.

  15. College drinking behaviors: mediational links between parenting styles, impulse control, and alcohol-related outcomes.

    PubMed

    Patock-Peckham, Julie A; Morgan-Lopez, Antonio A

    2006-06-01

    Mediational links between parenting styles (authoritative, authoritarian, permissive), impulsiveness (general control), drinking control (specific control), and alcohol use and abuse were tested. A pattern-mixture approach (for modeling non-ignorable missing data) with multiple-group structural equation models with 421 (206 female, 215 male) college students was used. Gender was examined as a potential moderator of parenting styles on control processes related to drinking. Specifically, the parent-child gender match was found to have implications for increased levels of impulsiveness (a significant mediator of parenting effects on drinking control). These findings suggest that a parent with a permissive parenting style who is the same gender as the respondent can directly influence control processes and indirectly influence alcohol use and abuse.

  16. A Two-Step Approach for Analysis of Nonignorable Missing Outcomes in Longitudinal Regression: an Application to Upstate KIDS Study.

    PubMed

    Liu, Danping; Yeung, Edwina H; McLain, Alexander C; Xie, Yunlong; Buck Louis, Germaine M; Sundaram, Rajeshwari

    2017-09-01

    Imperfect follow-up in longitudinal studies commonly leads to missing outcome data that can potentially bias the inference when the missingness is nonignorable; that is, the propensity of missingness depends on missing values in the data. In the Upstate KIDS Study, we seek to determine if the missingness of child development outcomes is nonignorable, and how a simple model assuming ignorable missingness would compare with more complicated models for a nonignorable mechanism. To correct for nonignorable missingness, the shared random effects model (SREM) jointly models the outcome and the missing mechanism. However, the computational complexity and lack of software packages has limited its practical applications. This paper proposes a novel two-step approach to handle nonignorable missing outcomes in generalized linear mixed models. We first analyse the missing mechanism with a generalized linear mixed model and predict values of the random effects; then, the outcome model is fitted adjusting for the predicted random effects to account for heterogeneity in the missingness propensity. Extensive simulation studies suggest that the proposed method is a reliable approximation to SREM, with a much faster computation. The nonignorability of missing data in the Upstate KIDS Study is estimated to be mild to moderate, and the analyses using the two-step approach or SREM are similar to the model assuming ignorable missingness. The two-step approach is a computationally straightforward method that can be conducted as sensitivity analyses in longitudinal studies to examine violations to the ignorable missingness assumption and the implications relative to health outcomes. © 2017 John Wiley & Sons Ltd.

  17. 75 FR 12667 - Airworthiness Directives; Learjet Inc. Model 45 Airplanes

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-17

    ... certain Model 45 airplanes. This AD requires a general visual inspection for cracked and missing ballscrew... sleeve or flap actuator for cracks, and replacement or modification of the flap actuator if necessary. This AD results from reports of cracked and missing ballscrew assembly sleeves of the flap actuators...

  18. A Bayesian model for time-to-event data with informative censoring

    PubMed Central

    Kaciroti, Niko A.; Raghunathan, Trivellore E.; Taylor, Jeremy M. G.; Julius, Stevo

    2012-01-01

    Randomized trials with dropouts or censored data and discrete time-to-event type outcomes are frequently analyzed using the Kaplan–Meier or product limit (PL) estimation method. However, the PL method assumes that the censoring mechanism is noninformative and when this assumption is violated, the inferences may not be valid. We propose an expanded PL method using a Bayesian framework to incorporate informative censoring mechanism and perform sensitivity analysis on estimates of the cumulative incidence curves. The expanded method uses a model, which can be viewed as a pattern mixture model, where odds for having an event during the follow-up interval (tk−1,tk], conditional on being at risk at tk−1, differ across the patterns of missing data. The sensitivity parameters relate the odds of an event, between subjects from a missing-data pattern with the observed subjects for each interval. The large number of the sensitivity parameters is reduced by considering them as random and assumed to follow a log-normal distribution with prespecified mean and variance. Then we vary the mean and variance to explore sensitivity of inferences. The missing at random (MAR) mechanism is a special case of the expanded model, thus allowing exploration of the sensitivity to inferences as departures from the inferences under the MAR assumption. The proposed approach is applied to data from the TRial Of Preventing HYpertension. PMID:22223746

  19. Utility of an airframe referenced spatial auditory display for general aviation operations

    NASA Astrophysics Data System (ADS)

    Naqvi, M. Hassan; Wigdahl, Alan J.; Ranaudo, Richard J.

    2009-05-01

    The University of Tennessee Space Institute (UTSI) completed flight testing with an airframe-referenced localized audio cueing display. The purpose was to assess its affect on pilot performance, workload, and situational awareness in two scenarios simulating single-pilot general aviation operations under instrument meteorological conditions. Each scenario consisted of 12 test procedures conducted under simulated instrument meteorological conditions, half with the cue off, and half with the cue on. Simulated aircraft malfunctions were strategically inserted at critical times during each test procedure. Ten pilots participated in the study; half flew a moderate workload scenario consisting of point to point navigation and holding pattern operations and half flew a high workload scenario consisting of non precision approaches and missed approach procedures. Flight data consisted of aircraft and navigation state parameters, NASA Task Load Index (TLX) assessments, and post-flight questionnaires. With localized cues there was slightly better pilot technical performance, a reduction in workload, and a perceived improvement in situational awareness. Results indicate that an airframe-referenced auditory display has utility and pilot acceptance in general aviation operations.

  20. Imaging in gynaecology: How good are we in identifying endometriomas?

    PubMed Central

    Van Holsbeke, C.; Van Calster, B.; Guerriero, S.; Savelli, L.; Leone, F.; Fischerova, D; Czekierdowski, A.; Fruscio, R.; Veldman, J.; Van de Putte, G.; Testa, A.C.; Bourne, T.; Valentin, L.; Timmerman, D.

    2009-01-01

    Aim: To evaluate the performance of subjective evaluation of ultrasound findings (pattern recognition) to discriminate endometriomas from other types of adnexal masses and to compare the demographic and ultrasound characteristics of the true positive cases with those cases that were presumed to be an endometrioma but proved to have a different histology (false positive cases) and the endometriomas missed by pattern recognition (false negative cases). Methods: All patients in the International Ovarian Tumor Analysis (IOTA ) studies were included for analysis. In the IOTA studies, patients with an adnexal mass that were preoperatively examined by expert sonologists following the same standardized ultrasound protocol were prospectively included in 21 international centres. Sensitivity and specificity to discriminate endometriomas from other types of adnexal masses using pattern recognition were calculated. Ultrasound and some demographic variables of the masses presumed to be an endometrioma were analysed (true positives and false positives) and compared with the variables of the endometriomas missed by pattern recognition (false negatives) as well as the true negatives. Results: IOTA phase 1, 1b and 2 included 3511 patients of which 2560 were benign (73%) and 951 malignant (27%). The dataset included 713 endometriomas. Sensitivity and specificity for pattern recognition were 81% (577/713) and 97% (2723/2798). The true positives were more often unilocular with ground glass echogenicity than the masses in any other category. Among the 75 false positive cases, 66 were benign but 9 were malignant (5 borderline tumours, 1 rare primary invasive tumour and 3 endometrioid adenocarcinomas). The presumed diagnosis suggested by the sonologist in case of a missed endometrioma was mostly functional cyst or cystadenoma. Conclusion: Expert sonologists can quite accurately discriminate endometriomas from other types of adnexal masses, but in this dataset 1% of the masses that were classified as endometrioma by pattern recognition proved to be malignancies. PMID:25478066

  1. Phonological perception by birds: budgerigars can perceive lexical stress.

    PubMed

    Hoeschele, Marisa; Fitch, W Tecumseh

    2016-05-01

    Metrical phonology is the perceptual "strength" in language of some syllables relative to others. The ability to perceive lexical stress is important, as it can help a listener segment speech and distinguish the meaning of words and sentences. Despite this importance, there has been little comparative work on the perception of lexical stress across species. We used a go/no-go operant paradigm to train human participants and budgerigars (Melopsittacus undulatus) to distinguish trochaic (stress-initial) from iambic (stress-final) two-syllable nonsense words. Once participants learned the task, we presented both novel nonsense words, and familiar nonsense words that had certain cues removed (e.g., pitch, duration, loudness, or vowel quality) to determine which cues were most important in stress perception. Members of both species learned the task and were then able to generalize to novel exemplars, showing categorical learning rather than rote memorization. Tests using reduced stimuli showed that humans could identify stress patterns with amplitude and pitch alone, but not with only duration or vowel quality. Budgerigars required more than one cue to be present and had trouble if vowel quality or amplitude were missing as cues. The results suggest that stress patterns in human speech can be decoded by other species. Further comparative stress-perception research with more species could help to determine what species characteristics predict this ability. In addition, tests with a variety of stimuli could help to determine how much this ability depends on general pattern learning processes versus vocalization-specific cues.

  2. Missing data in FFQs: making assumptions about item non-response.

    PubMed

    Lamb, Karen E; Olstad, Dana Lee; Nguyen, Cattram; Milte, Catherine; McNaughton, Sarah A

    2017-04-01

    FFQs are a popular method of capturing dietary information in epidemiological studies and may be used to derive dietary exposures such as nutrient intake or overall dietary patterns and diet quality. As FFQs can involve large numbers of questions, participants may fail to respond to all questions, leaving researchers to decide how to deal with missing data when deriving intake measures. The aim of the present commentary is to discuss the current practice for dealing with item non-response in FFQs and to propose a research agenda for reporting and handling missing data in FFQs. Single imputation techniques, such as zero imputation (assuming no consumption of the item) or mean imputation, are commonly used to deal with item non-response in FFQs. However, single imputation methods make strong assumptions about the missing data mechanism and do not reflect the uncertainty created by the missing data. This can lead to incorrect inference about associations between diet and health outcomes. Although the use of multiple imputation methods in epidemiology has increased, these have seldom been used in the field of nutritional epidemiology to address missing data in FFQs. We discuss methods for dealing with item non-response in FFQs, highlighting the assumptions made under each approach. Researchers analysing FFQs should ensure that missing data are handled appropriately and clearly report how missing data were treated in analyses. Simulation studies are required to enable systematic evaluation of the utility of various methods for handling item non-response in FFQs under different assumptions about the missing data mechanism.

  3. Missing data methods for dealing with missing items in quality of life questionnaires. A comparison by simulation of personal mean score, full information maximum likelihood, multiple imputation, and hot deck techniques applied to the SF-36 in the French 2003 decennial health survey.

    PubMed

    Peyre, Hugo; Leplège, Alain; Coste, Joël

    2011-03-01

    Missing items are common in quality of life (QoL) questionnaires and present a challenge for research in this field. It remains unclear which of the various methods proposed to deal with missing data performs best in this context. We compared personal mean score, full information maximum likelihood, multiple imputation, and hot deck techniques using various realistic simulation scenarios of item missingness in QoL questionnaires constructed within the framework of classical test theory. Samples of 300 and 1,000 subjects were randomly drawn from the 2003 INSEE Decennial Health Survey (of 23,018 subjects representative of the French population and having completed the SF-36) and various patterns of missing data were generated according to three different item non-response rates (3, 6, and 9%) and three types of missing data (Little and Rubin's "missing completely at random," "missing at random," and "missing not at random"). The missing data methods were evaluated in terms of accuracy and precision for the analysis of one descriptive and one association parameter for three different scales of the SF-36. For all item non-response rates and types of missing data, multiple imputation and full information maximum likelihood appeared superior to the personal mean score and especially to hot deck in terms of accuracy and precision; however, the use of personal mean score was associated with insignificant bias (relative bias <2%) in all studied situations. Whereas multiple imputation and full information maximum likelihood are confirmed as reference methods, the personal mean score appears nonetheless appropriate for dealing with items missing from completed SF-36 questionnaires in most situations of routine use. These results can reasonably be extended to other questionnaires constructed according to classical test theory.

  4. HIV-1 Full-Genome Phylogenetics of Generalized Epidemics in Sub-Saharan Africa: Impact of Missing Nucleotide Characters in Next-Generation Sequences

    PubMed Central

    Wymant, Chris; Colijn, Caroline; Danaviah, Siva; Essex, Max; Frost, Simon; Gall, Astrid; Gaseitsiwe, Simani; Grabowski, Mary K.; Gray, Ronald; Guindon, Stephane; von Haeseler, Arndt; Kaleebu, Pontiano; Kendall, Michelle; Kozlov, Alexey; Manasa, Justen; Minh, Bui Quang; Moyo, Sikhulile; Novitsky, Vlad; Nsubuga, Rebecca; Pillay, Sureshnee; Quinn, Thomas C.; Serwadda, David; Ssemwanga, Deogratius; Stamatakis, Alexandros; Trifinopoulos, Jana; Wawer, Maria; Brown, Andy Leigh; de Oliveira, Tulio; Kellam, Paul; Pillay, Deenan; Fraser, Christophe

    2017-01-01

    Abstract To characterize HIV-1 transmission dynamics in regions where the burden of HIV-1 is greatest, the “Phylogenetics and Networks for Generalised HIV Epidemics in Africa” consortium (PANGEA-HIV) is sequencing full-genome viral isolates from across sub-Saharan Africa. We report the first 3,985 PANGEA-HIV consensus sequences from four cohort sites (Rakai Community Cohort Study, n = 2,833; MRC/UVRI Uganda, n = 701; Mochudi Prevention Project, n = 359; Africa Health Research Institute Resistance Cohort, n = 92). Next-generation sequencing success rates varied: more than 80% of the viral genome from the gag to the nef genes could be determined for all sequences from South Africa, 75% of sequences from Mochudi, 60% of sequences from MRC/UVRI Uganda, and 22% of sequences from Rakai. Partial sequencing failure was primarily associated with low viral load, increased for amplicons closer to the 3′ end of the genome, was not associated with subtype diversity except HIV-1 subtype D, and remained significantly associated with sampling location after controlling for other factors. We assessed the impact of the missing data patterns in PANGEA-HIV sequences on phylogeny reconstruction in simulations. We found a threshold in terms of taxon sampling below which the patchy distribution of missing characters in next-generation sequences (NGS) has an excess negative impact on the accuracy of HIV-1 phylogeny reconstruction, which is attributable to tree reconstruction artifacts that accumulate when branches in viral trees are long. The large number of PANGEA-HIV sequences provides unprecedented opportunities for evaluating HIV-1 transmission dynamics across sub-Saharan Africa and identifying prevention opportunities. Molecular epidemiological analyses of these data must proceed cautiously because sequence sampling remains below the identified threshold and a considerable negative impact of missing characters on phylogeny reconstruction is expected. PMID:28540766

  5. HIV-1 full-genome phylogenetics of generalized epidemics in sub-Saharan Africa: impact of missing nucleotide characters in next-generation sequences.

    PubMed

    Ratmann, Oliver; Wymant, Chris; Colijn, Caroline; Danaviah, Siva; Essex, M; Frost, Simon D W; Gall, Astrid; Gaiseitsiwe, Simani; Grabowski, Mary; Gray, Ronald; Guindon, Stephane; von Haeseler, Arndt; Kaleebu, Pontiano; Kendall, Michelle; Kozlov, Alexey; Manasa, Justen; Minh, Bui Quang; Moyo, Sikhulile; Novitsky, Vladimir; Nsubuga, Rebecca; Pillay, Sureshnee; Quinn, Thomas C; Serwadda, David; Ssemwanga, Deogratius; Stamatakis, Alexandros; Trifinopoulos, Jana; Wawer, Maria; Leigh Brown, Andrew; de Oliveira, Tulio; Kellam, Paul; Pillay, Deenan; Fraser, Christophe

    2017-05-25

    To characterize HIV-1 transmission dynamics in regions where the burden of HIV-1 is greatest, the 'Phylogenetics and Networks for Generalised HIV Epidemics in Africa' consortium (PANGEA-HIV) is sequencing full-genome viral isolates from across sub-Saharan Africa. We report the first 3,985 PANGEA-HIV consensus sequences from four cohort sites (Rakai Community Cohort Study, n=2,833; MRC/UVRI Uganda, n=701; Mochudi Prevention Project, n=359; Africa Health Research Institute Resistance Cohort, n=92). Next-generation sequencing success rates varied: more than 80% of the viral genome from the gag to the nef genes could be determined for all sequences from South Africa, 75% of sequences from Mochudi, 60% of sequences from MRC/UVRI Uganda, and 22% of sequences from Rakai. Partial sequencing failure was primarily associated with low viral load, increased for amplicons closer to the 3' end of the genome, was not associated with subtype diversity except HIV-1 subtype D, and remained significantly associated with sampling location after controlling for other factors. We assessed the impact of the missing data patterns in PANGEA-HIV sequences on phylogeny reconstruction in simulations. We found a threshold in terms of taxon sampling below which the patchy distribution of missing characters in next-generation sequences has an excess negative impact on the accuracy of HIV-1 phylogeny reconstruction, which is attributable to tree reconstruction artifacts that accumulate when branches in viral trees are long. The large number of PANGEA-HIV sequences provides unprecedented opportunities for evaluating HIV-1 transmission dynamics across sub-Saharan Africa and identifying prevention opportunities. Molecular epidemiological analyses of these data must proceed cautiously because sequence sampling remains below the identified threshold and a considerable negative impact of missing characters on phylogeny reconstruction is expected.

  6. Spatial Copula Model for Imputing Traffic Flow Data from Remote Microwave Sensors

    PubMed Central

    Ma, Xiaolei; Du, Bowen; Yu, Bin

    2017-01-01

    Issues of missing data have become increasingly serious with the rapid increase in usage of traffic sensors. Analyses of the Beijing ring expressway have showed that up to 50% of microwave sensors pose missing values. The imputation of missing traffic data must be urgently solved although a precise solution that cannot be easily achieved due to the significant number of missing portions. In this study, copula-based models are proposed for the spatial interpolation of traffic flow from remote traffic microwave sensors. Most existing interpolation methods only rely on covariance functions to depict spatial correlation and are unsuitable for coping with anomalies due to Gaussian consumption. Copula theory overcomes this issue and provides a connection between the correlation function and the marginal distribution function of traffic flow. To validate copula-based models, a comparison with three kriging methods is conducted. Results indicate that copula-based models outperform kriging methods, especially on roads with irregular traffic patterns. Copula-based models demonstrate significant potential to impute missing data in large-scale transportation networks. PMID:28934164

  7. Time-series modeling of long-term weight self-monitoring data.

    PubMed

    Helander, Elina; Pavel, Misha; Jimison, Holly; Korhonen, Ilkka

    2015-08-01

    Long-term self-monitoring of weight is beneficial for weight maintenance, especially after weight loss. Connected weight scales accumulate time series information over long term and hence enable time series analysis of the data. The analysis can reveal individual patterns, provide more sensitive detection of significant weight trends, and enable more accurate and timely prediction of weight outcomes. However, long term self-weighing data has several challenges which complicate the analysis. Especially, irregular sampling, missing data, and existence of periodic (e.g. diurnal and weekly) patterns are common. In this study, we apply time series modeling approach on daily weight time series from two individuals and describe information that can be extracted from this kind of data. We study the properties of weight time series data, missing data and its link to individuals behavior, periodic patterns and weight series segmentation. Being able to understand behavior through weight data and give relevant feedback is desired to lead to positive intervention on health behaviors.

  8. Blue Note

    ScienceCinema

    Murray Gibson

    2017-12-09

    Argonne's Murray Gibson is a physicist whose life's work includes finding patterns among atoms. The love of distinguishing patterns also drives Gibson as a musician and Blues enthusiast."Blue" notes are very harmonic notes that are missing from the equal temperament scale.The techniques of piano blues and jazz represent the melding of African and Western music into something totally new and exciting.

  9. Patterns of Heart Attacks

    DTIC Science & Technology

    2010-06-01

    episode of the flu and because of these misdiagnoses , some cardiologists believe that the signs and symptoms of a heart attack are often missed [25...pattern. Coronary Artery Disease Chest Pain Diabetes Lung Cancer Anemias Atrial Fibrillation Hyperlipidemia Metabolic Disorders .1 Bucket 3: Spectral...8217Urologic disease, Male genital disease, Breast disease,Female genital disease ’Complications of pregnancy, Obstetric labor complication, Puerperal

  10. Blue Note

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Murray Gibson

    2007-04-27

    Argonne's Murray Gibson is a physicist whose life's work includes finding patterns among atoms. The love of distinguishing patterns also drives Gibson as a musician and Blues enthusiast."Blue" notes are very harmonic notes that are missing from the equal temperament scale.The techniques of piano blues and jazz represent the melding of African and Western music into something totally new and exciting.

  11. Outlier Removal in Model-Based Missing Value Imputation for Medical Datasets.

    PubMed

    Huang, Min-Wei; Lin, Wei-Chao; Tsai, Chih-Fong

    2018-01-01

    Many real-world medical datasets contain some proportion of missing (attribute) values. In general, missing value imputation can be performed to solve this problem, which is to provide estimations for the missing values by a reasoning process based on the (complete) observed data. However, if the observed data contain some noisy information or outliers, the estimations of the missing values may not be reliable or may even be quite different from the real values. The aim of this paper is to examine whether a combination of instance selection from the observed data and missing value imputation offers better performance than performing missing value imputation alone. In particular, three instance selection algorithms, DROP3, GA, and IB3, and three imputation algorithms, KNNI, MLP, and SVM, are used in order to find out the best combination. The experimental results show that that performing instance selection can have a positive impact on missing value imputation over the numerical data type of medical datasets, and specific combinations of instance selection and imputation methods can improve the imputation results over the mixed data type of medical datasets. However, instance selection does not have a definitely positive impact on the imputation result for categorical medical datasets.

  12. Predicting missing biomarker data in a longitudinal study of Alzheimer disease.

    PubMed

    Lo, Raymond Y; Jagust, William J

    2012-05-01

    To investigate predictors of missing data in a longitudinal study of Alzheimer disease (AD). The Alzheimer's Disease Neuroimaging Initiative (ADNI) is a clinic-based, multicenter, longitudinal study with blood, CSF, PET, and MRI scans repeatedly measured in 229 participants with normal cognition (NC), 397 with mild cognitive impairment (MCI), and 193 with mild AD during 2005-2007. We used univariate and multivariable logistic regression models to examine the associations between baseline demographic/clinical features and loss of biomarker follow-ups in ADNI. CSF studies tended to recruit and retain patients with MCI with more AD-like features, including lower levels of baseline CSF Aβ(42). Depression was the major predictor for MCI dropouts, while family history of AD kept more patients with AD enrolled in PET and MRI studies. Poor cognitive performance was associated with loss of follow-up in most biomarker studies, even among NC participants. The presence of vascular risk factors seemed more critical than cognitive function for predicting dropouts in AD. The missing data are not missing completely at random in ADNI and likely conditional on certain features in addition to cognitive function. Missing data predictors vary across biomarkers and even MCI and AD groups do not share the same missing data pattern. Understanding the missing data structure may help in the design of future longitudinal studies and clinical trials in AD.

  13. Predicting missing biomarker data in a longitudinal study of Alzheimer disease

    PubMed Central

    Jagust, William J.; Aisen, Paul; Jack, Clifford R.; Toga, Arthur W.; Beckett, Laurel; Gamst, Anthony; Soares, Holly; C. Green, Robert; Montine, Tom; Thomas, Ronald G.; Donohue, Michael; Walter, Sarah; Dale, Anders; Bernstein, Matthew; Felmlee, Joel; Fox, Nick; Thompson, Paul; Schuff, Norbert; Alexander, Gene; DeCarli, Charles; Bandy, Dan; Chen, Kewei; Morris, John; Lee, Virginia M.-Y.; Korecka, Magdalena; Crawford, Karen; Neu, Scott; Harvey, Danielle; Kornak, John; Saykin, Andrew J.; Foroud, Tatiana M.; Potkin, Steven; Shen, Li; Buckholtz, Neil; Kaye, Jeffrey; Dolen, Sara; Quinn, Joseph; Schneider, Lon; Pawluczyk, Sonia; Spann, Bryan M.; Brewer, James; Vanderswag, Helen; Heidebrink, Judith L.; Lord, Joanne L.; Petersen, Ronald; Johnson, Kris; Doody, Rachelle S.; Villanueva-Meyer, Javier; Chowdhury, Munir; Stern, Yaakov; Honig, Lawrence S.; Bell, Karen L.; Morris, John C.; Mintun, Mark A.; Schneider, Stacy; Marson, Daniel; Griffith, Randall; Clark, David; Grossman, Hillel; Tang, Cheuk; Marzloff, George; Toledo-Morrell, Leylade; Shah, Raj C.; Duara, Ranjan; Varon, Daniel; Roberts, Peggy; Albert, Marilyn S.; Pedroso, Julia; Toroney, Jaimie; Rusinek, Henry; de Leon, Mony J; De Santi, Susan M; Doraiswamy, P. Murali; Petrella, Jeffrey R.; Aiello, Marilyn; Clark, Christopher M.; Pham, Cassie; Nunez, Jessica; Smith, Charles D.; Given, Curtis A.; Hardy, Peter; Lopez, Oscar L.; Oakley, MaryAnn; Simpson, Donna M.; Ismail, M. Saleem; Brand, Connie; Richard, Jennifer; Mulnard, Ruth A.; Thai, Gaby; Mc-Adams-Ortiz, Catherine; Diaz-Arrastia, Ramon; Martin-Cook, Kristen; DeVous, Michael; Levey, Allan I.; Lah, James J.; Cellar, Janet S.; Burns, Jeffrey M.; Anderson, Heather S.; Laubinger, Mary M.; Bartzokis, George; Silverman, Daniel H.S.; Lu, Po H.; Graff-Radford MBBCH, Neill R; Parfitt, Francine; Johnson, Heather; Farlow, Martin; Herring, Scott; Hake, Ann M.; van Dyck, Christopher H.; MacAvoy, Martha G.; Benincasa, Amanda L.; Chertkow, Howard; Bergman, Howard; Hosein, Chris; Black, Sandra; Graham, Simon; Caldwell, Curtis; Hsiung, Ging-Yuek Robin; Feldman, Howard; Assaly, Michele; Kertesz, Andrew; Rogers, John; Trost, Dick; Bernick, Charles; Munic, Donna; Wu, Chuang-Kuo; Johnson, Nancy; Mesulam, Marsel; Sadowsky, Carl; Martinez, Walter; Villena, Teresa; Turner, Scott; Johnson, Kathleen B.; Behan, Kelly E.; Sperling, Reisa A.; Rentz, Dorene M.; Johnson, Keith A.; Rosen, Allyson; Tinklenberg, Jared; Ashford, Wes; Sabbagh, Marwan; Connor, Donald; Jacobson, Sandra; Killiany, Ronald; Norbash, Alexander; Nair, Anil; Obisesan, Thomas O.; Jayam-Trouth, Annapurni; Wang, Paul; Lerner, Alan; Hudson, Leon; Ogrocki, Paula; DeCarli, Charles; Fletcher, Evan; Carmichael, Owen; Kittur, Smita; Mirje, Seema; Borrie, Michael; Lee, T-Y; Bartha, Dr Rob; Johnson, Sterling; Asthana, Sanjay; Carlsson, Cynthia M.; Potkin, Steven G.; Preda, Adrian; Nguyen, Dana; Tariot, Pierre; Fleisher, Adam; Reeder, Stephanie; Bates, Vernice; Capote, Horacio; Rainka, Michelle; Hendin, Barry A.; Scharre, Douglas W.; Kataki, Maria; Zimmerman, Earl A.; Celmins, Dzintra; Brown, Alice D.; Gandy, Sam; Marenberg, Marjorie E.; Rovner, Barry W.; Pearlson, Godfrey; Anderson, Karen; Saykin, Andrew J.; Santulli, Robert B.; Englert, Jessica; Williamson, Jeff D.; Sink, Kaycee M.; Watkins, Franklin; Ott, Brian R.; Wu, Chuang-Kuo; Cohen, Ronald; Salloway, Stephen; Malloy, Paul; Correia, Stephen; Rosen, Howard J.; Miller, Bruce L.; Mintzer, Jacobo

    2012-01-01

    Objective: To investigate predictors of missing data in a longitudinal study of Alzheimer disease (AD). Methods: The Alzheimer's Disease Neuroimaging Initiative (ADNI) is a clinic-based, multicenter, longitudinal study with blood, CSF, PET, and MRI scans repeatedly measured in 229 participants with normal cognition (NC), 397 with mild cognitive impairment (MCI), and 193 with mild AD during 2005–2007. We used univariate and multivariable logistic regression models to examine the associations between baseline demographic/clinical features and loss of biomarker follow-ups in ADNI. Results: CSF studies tended to recruit and retain patients with MCI with more AD-like features, including lower levels of baseline CSF Aβ42. Depression was the major predictor for MCI dropouts, while family history of AD kept more patients with AD enrolled in PET and MRI studies. Poor cognitive performance was associated with loss of follow-up in most biomarker studies, even among NC participants. The presence of vascular risk factors seemed more critical than cognitive function for predicting dropouts in AD. Conclusion: The missing data are not missing completely at random in ADNI and likely conditional on certain features in addition to cognitive function. Missing data predictors vary across biomarkers and even MCI and AD groups do not share the same missing data pattern. Understanding the missing data structure may help in the design of future longitudinal studies and clinical trials in AD. PMID:22491869

  14. A Comparison of Joint Model and Fully Conditional Specification Imputation for Multilevel Missing Data

    ERIC Educational Resources Information Center

    Mistler, Stephen A.; Enders, Craig K.

    2017-01-01

    Multiple imputation methods can generally be divided into two broad frameworks: joint model (JM) imputation and fully conditional specification (FCS) imputation. JM draws missing values simultaneously for all incomplete variables using a multivariate distribution, whereas FCS imputes variables one at a time from a series of univariate conditional…

  15. A Comparison of Imputation Methods for Bayesian Factor Analysis Models

    ERIC Educational Resources Information Center

    Merkle, Edgar C.

    2011-01-01

    Imputation methods are popular for the handling of missing data in psychology. The methods generally consist of predicting missing data based on observed data, yielding a complete data set that is amiable to standard statistical analyses. In the context of Bayesian factor analysis, this article compares imputation under an unrestricted…

  16. Variable Selection in the Presence of Missing Data: Imputation-based Methods.

    PubMed

    Zhao, Yize; Long, Qi

    2017-01-01

    Variable selection plays an essential role in regression analysis as it identifies important variables that associated with outcomes and is known to improve predictive accuracy of resulting models. Variable selection methods have been widely investigated for fully observed data. However, in the presence of missing data, methods for variable selection need to be carefully designed to account for missing data mechanisms and statistical techniques used for handling missing data. Since imputation is arguably the most popular method for handling missing data due to its ease of use, statistical methods for variable selection that are combined with imputation are of particular interest. These methods, valid used under the assumptions of missing at random (MAR) and missing completely at random (MCAR), largely fall into three general strategies. The first strategy applies existing variable selection methods to each imputed dataset and then combine variable selection results across all imputed datasets. The second strategy applies existing variable selection methods to stacked imputed datasets. The third variable selection strategy combines resampling techniques such as bootstrap with imputation. Despite recent advances, this area remains under-developed and offers fertile ground for further research.

  17. VARIABLE SELECTION FOR REGRESSION MODELS WITH MISSING DATA

    PubMed Central

    Garcia, Ramon I.; Ibrahim, Joseph G.; Zhu, Hongtu

    2009-01-01

    We consider the variable selection problem for a class of statistical models with missing data, including missing covariate and/or response data. We investigate the smoothly clipped absolute deviation penalty (SCAD) and adaptive LASSO and propose a unified model selection and estimation procedure for use in the presence of missing data. We develop a computationally attractive algorithm for simultaneously optimizing the penalized likelihood function and estimating the penalty parameters. Particularly, we propose to use a model selection criterion, called the ICQ statistic, for selecting the penalty parameters. We show that the variable selection procedure based on ICQ automatically and consistently selects the important covariates and leads to efficient estimates with oracle properties. The methodology is very general and can be applied to numerous situations involving missing data, from covariates missing at random in arbitrary regression models to nonignorably missing longitudinal responses and/or covariates. Simulations are given to demonstrate the methodology and examine the finite sample performance of the variable selection procedures. Melanoma data from a cancer clinical trial is presented to illustrate the proposed methodology. PMID:20336190

  18. Is using multiple imputation better than complete case analysis for estimating a prevalence (risk) difference in randomized controlled trials when binary outcome observations are missing?

    PubMed

    Mukaka, Mavuto; White, Sarah A; Terlouw, Dianne J; Mwapasa, Victor; Kalilani-Phiri, Linda; Faragher, E Brian

    2016-07-22

    Missing outcomes can seriously impair the ability to make correct inferences from randomized controlled trials (RCTs). Complete case (CC) analysis is commonly used, but it reduces sample size and is perceived to lead to reduced statistical efficiency of estimates while increasing the potential for bias. As multiple imputation (MI) methods preserve sample size, they are generally viewed as the preferred analytical approach. We examined this assumption, comparing the performance of CC and MI methods to determine risk difference (RD) estimates in the presence of missing binary outcomes. We conducted simulation studies of 5000 simulated data sets with 50 imputations of RCTs with one primary follow-up endpoint at different underlying levels of RD (3-25 %) and missing outcomes (5-30 %). For missing at random (MAR) or missing completely at random (MCAR) outcomes, CC method estimates generally remained unbiased and achieved precision similar to or better than MI methods, and high statistical coverage. Missing not at random (MNAR) scenarios yielded invalid inferences with both methods. Effect size estimate bias was reduced in MI methods by always including group membership even if this was unrelated to missingness. Surprisingly, under MAR and MCAR conditions in the assessed scenarios, MI offered no statistical advantage over CC methods. While MI must inherently accompany CC methods for intention-to-treat analyses, these findings endorse CC methods for per protocol risk difference analyses in these conditions. These findings provide an argument for the use of the CC approach to always complement MI analyses, with the usual caveat that the validity of the mechanism for missingness be thoroughly discussed. More importantly, researchers should strive to collect as much data as possible.

  19. Persons with dementia missing in the community: is it wandering or something unique?

    PubMed

    Rowe, Meredeth A; Vandeveer, Sydney S; Greenblum, Catherine A; List, Cassandra N; Fernandez, Rachael M; Mixson, Natalie E; Ahn, Hyo C

    2011-06-05

    At some point in the disease process many persons with dementia (PWD) will have a missing incident and be unable to safely return to their care setting. In previous research studies, researchers have begun to question whether this phenomenon should continue to be called wandering since the antecedents and characteristics of a missing incident are dissimilar to accepted definitions of wandering in dementia. The purpose of this study was to confirm previous findings regarding the antecedents and characteristics of missing incidents, understand the differences between those found dead and alive, and compare the characteristics of a missing incident to that of wandering. A retrospective design was used to analyse 325 newspaper reports of PWD missing in the community. The primary antecedent to a missing incident, particularly in community-dwelling PWD, was becoming lost while conducting a normal and permitted activity alone in the community. The other common antecedent was a lapse in supervision with the expectation that the PWD would remain in a safe location but did not. Deaths most commonly occurred in unpopulated areas due to exposure and drowning. Those who died were found closer to the place last seen and took longer to find, but there were no significant differences in gender or age. The key characteristics of a missing incident were: unpredictable, non-repetitive, temporally appropriate but spatially-disordered, and while using multiple means of movement (walking, car, public transportation). Missing incidents occurred without the discernible pattern present in wandering such as lapping or pacing, repetitive and temporally-disordered. This research supports the mounting evidence that the concept of wandering, in its formal sense, and missing incidents are two distinct concepts. It will be important to further develop the concept of missing incidents by identifying the differences and similarities from wandering. This will allow a more targeted assessment and intervention strategy for each problem.

  20. Persons with dementia missing in the community: Is it wandering or something unique?

    PubMed Central

    2011-01-01

    Background At some point in the disease process many persons with dementia (PWD) will have a missing incident and be unable to safely return to their care setting. In previous research studies, researchers have begun to question whether this phenomenon should continue to be called wandering since the antecedents and characteristics of a missing incident are dissimilar to accepted definitions of wandering in dementia. The purpose of this study was to confirm previous findings regarding the antecedents and characteristics of missing incidents, understand the differences between those found dead and alive, and compare the characteristics of a missing incident to that of wandering. Methods A retrospective design was used to analyse 325 newspaper reports of PWD missing in the community. Results The primary antecedent to a missing incident, particularly in community-dwelling PWD, was becoming lost while conducting a normal and permitted activity alone in the community. The other common antecedent was a lapse in supervision with the expectation that the PWD would remain in a safe location but did not. Deaths most commonly occurred in unpopulated areas due to exposure and drowning. Those who died were found closer to the place last seen and took longer to find, but there were no significant differences in gender or age. The key characteristics of a missing incident were: unpredictable, non-repetitive, temporally appropriate but spatially-disordered, and while using multiple means of movement (walking, car, public transportation). Missing incidents occurred without the discernible pattern present in wandering such as lapping or pacing, repetitive and temporally-disordered. Conclusions This research supports the mounting evidence that the concept of wandering, in its formal sense, and missing incidents are two distinct concepts. It will be important to further develop the concept of missing incidents by identifying the differences and similarities from wandering. This will allow a more targeted assessment and intervention strategy for each problem. PMID:21639942

  1. Handling missing Mini-Mental State Examination (MMSE) values: Results from a cross-sectional long-term-care study.

    PubMed

    Godin, Judith; Keefe, Janice; Andrew, Melissa K

    2017-04-01

    Missing values are commonly encountered on the Mini Mental State Examination (MMSE), particularly when administered to frail older people. This presents challenges for MMSE scoring in research settings. We sought to describe missingness in MMSEs administered in long-term-care facilities (LTCF) and to compare and contrast approaches to dealing with missing items. As part of the Care and Construction project in Nova Scotia, Canada, LTCF residents completed an MMSE. Different methods of dealing with missing values (e.g., use of raw scores, raw scores/number of items attempted, scale-level multiple imputation [MI], and blended approaches) are compared to item-level MI. The MMSE was administered to 320 residents living in 23 LTCF. The sample was predominately female (73%), and 38% of participants were aged >85 years. At least one item was missing from 122 (38.2%) of the MMSEs. Data were not Missing Completely at Random (MCAR), χ 2 (1110) = 1,351, p < 0.001. Using raw scores for those missing <6 items in combination with scale-level MI resulted in the regression coefficients and standard errors closest to item-level MI. Patterns of missing items often suggest systematic problems, such as trouble with manual dexterity, literacy, or visual impairment. While these observations may be relatively easy to take into account in clinical settings, non-random missingness presents challenges for research and must be considered in statistical analyses. We present suggestions for dealing with missing MMSE data based on the extent of missingness and the goal of analyses. Copyright © 2016 The Authors. Production and hosting by Elsevier B.V. All rights reserved.

  2. Intracoronary beta-radiation for the treatment of patients at very high risk for recurrence of in-stent restenosis: a single center experience.

    PubMed

    Parenti, Dennis Zavalloni; Marsico, Federica; Tosi, Giovanni; Catalano, Gianpiero; Maiello, Luigi; Milone, Francesco; Carcagnì, Addolorata; Pron, Paolo Giay; Orecchia, Roberto; Presbitero, Patrizia

    2003-03-01

    Intracoronary brachytherapy has significantly reduced the recurrence of in-stent restenosis. The aim of this study was to evaluate the feasibility, safety and efficacy of intracoronary beta-radiation in patients at very high risk for recurrence of in-stent restenosis. We analyzed 42 patients with 50 lesions submitted to catheter-based beta-radiation (Beta-Cath System, Novoste Corporation, Norcross, GA, USA) for in-stent restenosis. Thirty-eight lesions were at the second restenosis, 8 at the third, and 4 at the fourth; a diffuse pattern was present in 78%. Balloon angioplasty was performed for 30 lesions (60%) and the cutting balloon technique for 20 (40%). In 12 lesions further 14 stents had to be deployed (28%). The delivery catheter was successfully positioned in 96% of the procedures. The mean dwell time was 179 +/- 50 s with a radiation dose ranging from 18.4 to 25.3 Gy, depending on the vessel size. A complete angiographic success without coronary dissection and without any additional stenting after radiation delivery was achieved in 86%. At follow-up (7.2 +/- 2.1 months), the overall restenosis rate was 30.4% (14 lesions). A recurrence was detected in 1/11 lesions with initial focal pattern and in 13/39 lesions with initial diffuse pattern. The restenosis rate was higher in patients in whom a geographic miss had occurred (p < 0.05 vs lesions without geographic miss) and in those in whom a new stent had been deployed (p < 0.05 vs lesions treated without a stent). Brachytherapy reduces the in-stent restenosis rate in patients who are at very high risk of recurrence. The restenosis pattern, geographic miss and new stent deployment seem to be negative prognostic factors for recurrence of restenosis.

  3. 7 CFR 201.56-6 - Legume or pea family, Fabaceae (Leguminosae).

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... necrosis or decay. (B) All other kinds: (1) Both missing and the seedling generally weak. (2) [Reserved... remaining attached. (B) Less than half of the original tissue free of necrosis or decay. (ii) Epicotyl: (A... necrosis or decay. (ii) Epicotyl: (A) Missing. (B) Less than one primary leaf. (C) Deep open cracks. (D...

  4. 7 CFR 201.56-6 - Legume or pea family, Fabaceae (Leguminosae).

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... necrosis or decay. (B) All other kinds: (1) Both missing and the seedling generally weak. (2) [Reserved... remaining attached. (B) Less than half of the original tissue free of necrosis or decay. (ii) Epicotyl: (A... necrosis or decay. (ii) Epicotyl: (A) Missing. (B) Less than one primary leaf. (C) Deep open cracks. (D...

  5. Growth Modeling with Nonignorable Dropout: Alternative Analyses of the STAR*D Antidepressant Trial

    ERIC Educational Resources Information Center

    Muthen, Bengt; Asparouhov, Tihomir; Hunter, Aimee M.; Leuchter, Andrew F.

    2011-01-01

    This article uses a general latent variable framework to study a series of models for nonignorable missingness due to dropout. Nonignorable missing data modeling acknowledges that missingness may depend not only on covariates and observed outcomes at previous time points as with the standard missing at random assumption, but also on latent…

  6. Chapter 5 - Missing Feedback in Payments for Ecosystem Services

    Treesearch

    Trista M. Patterson; Dana L. Coelho

    2008-01-01

    A general systems analysis of current approaches to payments for ecosystem services reveals a weakness, a missing feedback that ought to be in place pushing the system toward its goal of balancing human needs with the adaptive capacity of ecosystems. In situations of rising demand for ecosystem services among limited means for producing them, the likelihood that...

  7. Assessing written communication during interhospital transfers of emergency general surgery patients

    PubMed Central

    Harl, Felicity N.R.; Saucke, Megan C.; Greenberg, Caprice C.; Ingraham, Angela M.

    2017-01-01

    Background Poor communication causes fragmented care. Studies of transitions of care within a hospital and on discharge suggest significant communication deficits. Communication during transfers between hospitals has not been well studied. We assessed the written communication provided during interhospital transfers of emergency general surgery patients. We hypothesized that patients are transferred with incomplete documentation from referring facilities. Methods We performed a retrospective review of written communication provided during interhospital transfers to our emergency department (ED) from referring EDs for emergency general surgical evaluation between January 1, 2014 and January 1, 2016. Elements of written communication were abstracted from referring facility documents scanned into the medical record using a standardized abstraction protocol. Descriptive statistics summarized the information communicated. Results A total of 129 patients met inclusion criteria. 87.6% (n = 113) of charts contained referring hospital documents. 42.5% (n = 48) were missing history and physicals. Diagnoses were missing in 9.7% (n = 11). Ninety-one computed tomography scans were performed; a mong 70 with reads, final reads were absent for 70.0% (n = 49). 45 ultrasounds and x-rays were performed; among 27 with reads, final reads were missing for 80.0% (n = 36). Reasons for transfer were missing in 18.6% (n = 21). Referring hospital physicians outside the ED were consulted in 32.7% (n = 37); consultants’ notes were absent in 89.2% (n = 33). In 12.4% (n = 14), referring documents arrived after the patient’s ED arrival and were not part of the original documentation provided. Conclusions This study documents that information important to patient care is often missing in the written communication provided during interhospital transfers. This gap affords a foundation for standardizing provider communication during interhospital transfers. PMID:28624064

  8. Using Simplified Sudoku to Promote and Improve Pattern Discovery Skills among School Children

    ERIC Educational Resources Information Center

    Tengah, Khairul A.

    2011-01-01

    As part of promoting and improving pattern discovery skills among school children, a Sudoku puzzle can be used as example of a problem solving task. A simplified version of the puzzle will be used first to explain the aim and reinforce the rules of solving the puzzle. Three strategies--"Strategy of Obvious Missing Number, Strategy of…

  9. Meth mouth severity in response to drug-use patterns and dental access in methamphetamine users.

    PubMed

    Brown, Ronni E; Morisky, Donald E; Silverstein, Steven J

    2013-06-01

    Meth mouth is the rapid development of tooth decay in methamphetamine users. Our study questioned whether drug-use patterns and dental care access are risk factors affecting the severity of meth mouth. Participants received dental examinations, and the number of decayed, missing and filled teeth (DMFT) were counted and used to measure meth mouth severity.

  10. Study on the generation technology of Li brocade pattern mutant genes based on the AI and Java technology

    NASA Astrophysics Data System (ADS)

    Zhou, Yuping; Zhang, Qi

    2018-04-01

    In the information environment, digital and information processing to Li brocade patterns reveals an important means of Li ethnic style and inheriting the national culture. Adobe Illustrator CS3 and Java language were used in the paper to make "variation" processing to Li brocade patterns, and generate "Li brocade pattern mutant genes". The generation of pattern mutant genes includes color mutation, shape mutation, adding and missing transform, and twisted transform, etc. Research shows that Li brocade pattern mutant genes can be generated by using the Adobe Illustrator CS3 and the image processing tools of Java language edit, etc.

  11. Analysis of cohort studies with multivariate and partially observed disease classification data.

    PubMed

    Chatterjee, Nilanjan; Sinha, Samiran; Diver, W Ryan; Feigelson, Heather Spencer

    2010-09-01

    Complex diseases like cancers can often be classified into subtypes using various pathological and molecular traits of the disease. In this article, we develop methods for analysis of disease incidence in cohort studies incorporating data on multiple disease traits using a two-stage semiparametric Cox proportional hazards regression model that allows one to examine the heterogeneity in the effect of the covariates by the levels of the different disease traits. For inference in the presence of missing disease traits, we propose a generalization of an estimating equation approach for handling missing cause of failure in competing-risk data. We prove asymptotic unbiasedness of the estimating equation method under a general missing-at-random assumption and propose a novel influence-function-based sandwich variance estimator. The methods are illustrated using simulation studies and a real data application involving the Cancer Prevention Study II nutrition cohort.

  12. Search for supersymmetry in pp collisions at √7 TeV in events with two photons and missing transverse energy.

    PubMed

    Chatrchyan, S; Khachatryan, V; Sirunyan, A M; Tumasyan, A; Adam, W; Bergauer, T; Dragicevic, M; Erö, J; Fabjan, C; Friedl, M; Frühwirth, R; Ghete, V M; Hammer, J; Hänsel, S; Hoch, M; Hörmann, N; Hrubec, J; Jeitler, M; Kasieczka, G; Kiesenhofer, W; Krammer, M; Liko, D; Mikulec, I; Pernicka, M; Rohringer, H; Schöfbeck, R; Strauss, J; Teischinger, F; Wagner, P; Waltenberger, W; Walzel, G; Widl, E; Wulz, C-E; Mossolov, V; Shumeiko, N; Suarez Gonzalez, J; Benucci, L; De Wolf, E A; Janssen, X; Maes, T; Mucibello, L; Ochesanu, S; Roland, B; Rougny, R; Selvaggi, M; Van Haevermaet, H; Van Mechelen, P; Van Remortel, N; Blekman, F; Blyweert, S; D'Hondt, J; Devroede, O; Gonzalez Suarez, R; Kalogeropoulos, A; Maes, J; Maes, M; Van Doninck, W; Van Mulders, P; Van Onsem, G P; Villella, I; Charaf, O; Clerbaux, B; De Lentdecker, G; Dero, V; Gay, A P R; Hammad, G H; Hreus, T; Marage, P E; Thomas, L; Vander Velde, C; Vanlaer, P; Adler, V; Cimmino, A; Costantini, S; Grunewald, M; Klein, B; Lellouch, J; Marinov, A; McCartin, J; Ryckbosch, D; Thyssen, F; Tytgat, M; Vanelderen, L; Verwilligen, P; Walsh, S; Zaganidis, N; Basegmez, S; Bruno, G; Caudron, J; Ceard, L; Cortina Gil, E; De Favereau De Jeneret, J; Delaere, C; Favart, D; Giammanco, A; Grégoire, G; Hollar, J; Lemaitre, V; Liao, J; Militaru, O; Ovyn, S; Pagano, D; Pin, A; Piotrzkowski, K; Schul, N; Beliy, N; Caebergs, T; Daubie, E; Alves, G A; De Jesus Damiao, D; Pol, M E; Souza, M H G; Carvalho, W; Da Costa, E M; De Oliveira Martins, C; Fonseca De Souza, S; Mundim, L; Nogima, H; Oguri, V; Prado Da Silva, W L; Santoro, A; Silva Do Amaral, S M; Sznajder, A; Torres Da Silva De Araujo, F; Dias, F A; Fernandez Perez Tomei, T R; Gregores, E M; Lagana, C; Marinho, F; Mercadante, P G; Novaes, S F; Padula, Sandra S; Darmenov, N; Dimitrov, L; Genchev, V; Iaydjiev, P; Piperov, S; Rodozov, M; Stoykova, S; Sultanov, G; Tcholakov, V; Trayanov, R; Vankov, I; Dimitrov, A; Hadjiiska, R; Karadzhinova, A; Kozhuharov, V; Litov, L; Mateev, M; Pavlov, B; Petkov, P; Bian, J G; Chen, G M; Chen, H S; Jiang, C H; Liang, D; Liang, S; Meng, X; Tao, J; Wang, J; Wang, J; Wang, X; Wang, Z; Xiao, H; Xu, M; Zang, J; Zhang, Z; Ban, Y; Guo, S; Guo, Y; Li, W; Mao, Y; Qian, S J; Teng, H; Zhang, L; Zhu, B; Zou, W; Cabrera, A; Gomez Moreno, B; Ocampo Rios, A A; Osorio Oliveros, A F; Sanabria, J C; Godinovic, N; Lelas, D; Lelas, K; Plestina, R; Polic, D; Puljak, I; Antunovic, Z; Dzelalija, M; Brigljevic, V; Duric, S; Kadija, K; Morovic, S; Attikis, A; Galanti, M; Mousa, J; Nicolaou, C; Ptochos, F; Razis, P A; Finger, M; Finger, M; Assran, Y; Khalil, S; Mahmoud, M A; Hektor, A; Kadastik, M; Müntel, M; Raidal, M; Rebane, L; Azzolini, V; Eerola, P; Fedi, G; Czellar, S; Härkönen, J; Heikkinen, A; Karimäki, V; Kinnunen, R; Kortelainen, M J; Lampén, T; Lassila-Perini, K; Lehti, S; Lindén, T; Luukka, P; Mäenpää, T; Tuominen, E; Tuominiemi, J; Tuovinen, E; Ungaro, D; Wendland, L; Banzuzi, K; Korpela, A; Tuuva, T; Sillou, D; Besancon, M; Choudhury, S; Dejardin, M; Denegri, D; Fabbro, B; Faure, J L; Ferri, F; Ganjour, S; Gentit, F X; Givernaud, A; Gras, P; Hamel de Monchenault, G; Jarry, P; Locci, E; Malcles, J; Marionneau, M; Millischer, L; Rander, J; Rosowsky, A; Shreyber, I; Titov, M; Verrecchia, P; Baffioni, S; Beaudette, F; Benhabib, L; Bianchini, L; Bluj, M; Broutin, C; Busson, P; Charlot, C; Dahms, T; Dobrzynski, L; Elgammal, S; Granier de Cassagnac, R; Haguenauer, M; Miné, P; Mironov, C; Ochando, C; Paganini, P; Sabes, D; Salerno, R; Sirois, Y; Thiebaux, C; Wyslouch, B; Zabi, A; Agram, J-L; Andrea, J; Bloch, D; Bodin, D; Brom, J-M; Cardaci, M; Chabert, E C; Collard, C; Conte, E; Drouhin, F; Ferro, C; Fontaine, J-C; Gelé, D; Goerlach, U; Greder, S; Juillot, P; Karim, M; Le Bihan, A-C; Mikami, Y; Van Hove, P; Fassi, F; Mercier, D; Baty, C; Beauceron, S; Beaupere, N; Bedjidian, M; Bondu, O; Boudoul, G; Boumediene, D; Brun, H; Chierici, R; Contardo, D; Depasse, P; El Mamouni, H; Fay, J; Gascon, S; Ille, B; Kurca, T; Le Grand, T; Lethuillier, M; 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D'Alfonso, M; Danielson, T; Flowers, K; Geffert, P; Incandela, J; Justus, C; Kalavase, P; Koay, S A; Kovalskyi, D; Krutelyov, V; Lowette, S; McColl, N; Pavlunin, V; Rebassoo, F; Ribnik, J; Richman, J; Rossin, R; Stuart, D; To, W; Vlimant, J R; Apresyan, A; Bornheim, A; Bunn, J; Chen, Y; Gataullin, M; Ma, Y; Mott, A; Newman, H B; Rogan, C; Shin, K; Timciuc, V; Traczyk, P; Veverka, J; Wilkinson, R; Yang, Y; Zhu, R Y; Akgun, B; Carroll, R; Ferguson, T; Iiyama, Y; Jang, D W; Jun, S Y; Liu, Y F; Paulini, M; Russ, J; Vogel, H; Vorobiev, I; Cumalat, J P; Dinardo, M E; Drell, B R; Edelmaier, C J; Ford, W T; Gaz, A; Heyburn, B; Luiggi Lopez, E; Nauenberg, U; Smith, J G; Stenson, K; Ulmer, K A; Wagner, S R; Zang, S L; Agostino, L; Alexander, J; Cassel, D; Chatterjee, A; Das, S; Eggert, N; Gibbons, L K; Heltsley, B; Hopkins, W; Khukhunaishvili, A; Kreis, B; Nicolas Kaufman, G; Patterson, J R; Puigh, D; Ryd, A; Salvati, E; Shi, X; Sun, W; Teo, W D; Thom, J; Thompson, J; Vaughan, J; Weng, Y; Winstrom, L; Wittich, P; Biselli, A; Cirino, G; Winn, D; Abdullin, S; Albrow, M; Anderson, J; Apollinari, G; Atac, M; Bakken, J A; Banerjee, S; Bauerdick, L A T; Beretvas, A; Berryhill, J; Bhat, P C; Bloch, I; Borcherding, F; Burkett, K; Butler, J N; Chetluru, V; Cheung, H W K; Chlebana, F; Cihangir, S; Cooper, W; Eartly, D P; Elvira, V D; Esen, S; Fisk, I; Freeman, J; Gao, Y; Gottschalk, E; Green, D; Gunthoti, K; Gutsche, O; Hanlon, J; Harris, R M; Hirschauer, J; Hooberman, B; Jensen, H; Johnson, M; Joshi, U; Khatiwada, R; Klima, B; Kousouris, K; Kunori, S; Kwan, S; Leonidopoulos, C; Limon, P; Lincoln, D; Lipton, R; Lykken, J; Maeshima, K; Marraffino, J M; Mason, D; McBride, P; Miao, T; Mishra, K; Mrenna, S; Musienko, Y; Newman-Holmes, C; O'Dell, V; Pordes, R; Prokofyev, O; Saoulidou, N; Sexton-Kennedy, E; Sharma, S; Spalding, W J; Spiegel, L; Tan, P; Taylor, L; Tkaczyk, S; Uplegger, L; Vaandering, E W; Vidal, R; Whitmore, J; Wu, W; Yang, F; Yumiceva, F; Yun, J C; Acosta, D; Avery, P; Bourilkov, D; Chen, M; De Gruttola, M; Di Giovanni, G P; Dobur, D; Drozdetskiy, A; Field, R D; Fisher, M; Fu, Y; Furic, I K; Gartner, J; Kim, B; Konigsberg, J; Korytov, A; Kropivnitskaya, A; Kypreos, T; Matchev, K; Mitselmakher, G; Muniz, L; Prescott, C; Remington, R; Schmitt, M; Scurlock, B; Sellers, P; Skhirtladze, N; Snowball, M; Wang, D; Yelton, J; Zakaria, M; Ceron, C; Gaultney, V; Kramer, L; Lebolo, L M; Linn, S; Markowitz, P; Martinez, G; Mesa, D; Rodriguez, J L; Adams, T; Askew, A; Bandurin, D; Bochenek, J; Chen, J; Diamond, B; Gleyzer, S V; Haas, J; Hagopian, S; Hagopian, V; Jenkins, M; Johnson, K F; Prosper, H; Quertenmont, L; Sekmen, S; Veeraraghavan, V; Baarmand, M M; Dorney, B; Guragain, S; Hohlmann, M; Kalakhety, H; Ralich, R; Vodopiyanov, I; Adams, M R; Anghel, I M; Apanasevich, L; Bai, Y; Bazterra, V E; Betts, R R; Callner, J; Cavanaugh, R; Dragoiu, C; Gauthier, L; Gerber, C E; Hofman, D J; Khalatyan, S; Kunde, G J; Lacroix, F; Malek, M; O'Brien, C; Silvestre, C; Smoron, A; Strom, D; Varelas, N; Akgun, U; Albayrak, E A; Bilki, B; Clarida, W; Duru, F; Lae, C K; McCliment, E; Merlo, J-P; Mermerkaya, H; Mestvirishvili, A; Moeller, A; Nachtman, J; Newsom, C R; Norbeck, E; Olson, J; Onel, Y; Ozok, F; Sen, S; Wetzel, J; Yetkin, T; Yi, K; Barnett, B A; Blumenfeld, B; Bonato, A; Eskew, C; Fehling, D; Giurgiu, G; Gritsan, A V; Hu, G; Maksimovic, P; Rappoccio, S; Swartz, M; Tran, N V; Whitbeck, A; Baringer, P; Bean, A; Benelli, G; Grachov, O; Kenny Iii, R P; Murray, M; Noonan, D; Sanders, S; Wood, J S; Zhukova, V; Barfuss, A F; Bolton, T; Chakaberia, I; Ivanov, A; Khalil, S; Makouski, M; Maravin, Y; Shrestha, S; Svintradze, I; Wan, Z; Gronberg, J; Lange, D; Wright, D; Baden, A; Boutemeur, M; Eno, S C; Ferencek, D; Gomez, J A; Hadley, N J; Kellogg, R G; Kirn, M; Lu, Y; Mignerey, A C; Rossato, K; Rumerio, P; Santanastasio, F; Skuja, A; Temple, J; Tonjes, M B; Tonwar, S C; Twedt, E; Alver, B; Bauer, G; Bendavid, J; Busza, W; Butz, E; Cali, I A; Chan, M; Dutta, V; Everaerts, P; Gomez Ceballos, G; Goncharov, M; Hahn, K A; Harris, P; Kim, Y; Klute, M; Lee, Y-J; Li, W; Loizides, C; Luckey, P D; Ma, T; Nahn, S; Paus, C; Ralph, D; Roland, C; Roland, G; Rudolph, M; Stephans, G S F; Stöckli, F; Sumorok, K; Sung, K; Wenger, E A; Xie, S; Yang, M; Yilmaz, Y; Yoon, A S; Zanetti, M; Cooper, S I; Cushman, P; Dahmes, B; De Benedetti, A; Dudero, P R; Franzoni, G; Haupt, J; Klapoetke, K; Kubota, Y; Mans, J; Rekovic, V; Rusack, R; Sasseville, M; Singovsky, A; Cremaldi, L M; Godang, R; Kroeger, R; Perera, L; Rahmat, R; Sanders, D A; Summers, D; Bloom, K; Bose, S; Butt, J; Claes, D R; Dominguez, A; Eads, M; Keller, J; Kelly, T; Kravchenko, I; Lazo-Flores, J; Malbouisson, H; Malik, S; Snow, G R; Baur, U; Godshalk, A; Iashvili, I; Jain, S; Kharchilava, A; Kumar, A; Shipkowski, S P; Smith, K; Alverson, G; Barberis, E; Baumgartel, D; Boeriu, O; Chasco, M; Reucroft, S; Swain, J; Trocino, D; Wood, D; Zhang, J; Anastassov, A; Kubik, A; Odell, N; Ofierzynski, R A; Pollack, B; Pozdnyakov, A; Schmitt, M; Stoynev, S; Velasco, M; Won, S; Antonelli, L; Berry, D; Hildreth, M; Jessop, C; Karmgard, D J; Kolb, J; Kolberg, T; Lannon, K; Luo, W; Lynch, S; Marinelli, N; Morse, D M; Pearson, T; Ruchti, R; Slaunwhite, J; Valls, N; Wayne, M; Ziegler, J; Bylsma, B; Durkin, L S; Gu, J; Hill, C; Killewald, P; Kotov, K; Ling, T Y; Rodenburg, M; Williams, G; Adam, N; Berry, E; Elmer, P; Gerbaudo, D; Halyo, V; Hebda, P; Hunt, A; Jones, J; Laird, E; Lopes Pegna, D; Marlow, D; Medvedeva, T; Mooney, M; Olsen, J; Piroué, P; Quan, X; Saka, H; Stickland, D; Tully, C; Werner, J S; Zuranski, A; Acosta, J G; Huang, X T; Lopez, A; Mendez, H; Oliveros, S; Ramirez Vargas, J E; Zatserklyaniy, A; Alagoz, E; Barnes, V E; Bolla, G; Borrello, L; Bortoletto, D; Everett, A; Garfinkel, A F; Gutay, L; Hu, Z; Jones, M; Koybasi, O; Kress, M; Laasanen, A T; Leonardo, N; Liu, C; Maroussov, V; Merkel, P; Miller, D H; Neumeister, N; Shipsey, I; Silvers, D; Svyatkovskiy, A; Yoo, H D; Zablocki, J; Zheng, Y; Jindal, P; Parashar, N; Boulahouache, C; Cuplov, V; Ecklund, K M; Geurts, F J M; Padley, B P; Redjimi, R; Roberts, J; Zabel, J; Betchart, B; Bodek, A; Chung, Y S; Covarelli, R; de Barbaro, P; Demina, R; Eshaq, Y; Flacher, H; Garcia-Bellido, A; Goldenzweig, P; Gotra, Y; Han, J; Harel, A; Miner, D C; Orbaker, D; Petrillo, G; Vishnevskiy, D; Zielinski, M; Bhatti, A; Ciesielski, R; Demortier, L; Goulianos, K; Lungu, G; Malik, S; Mesropian, C; Yan, M; Atramentov, O; Barker, A; Duggan, D; Gershtein, Y; Gray, R; Halkiadakis, E; Hidas, D; Hits, D; Lath, A; Panwalkar, S; Patel, R; Richards, A; Rose, K; Schnetzer, S; Somalwar, S; Stone, R; Thomas, S; Cerizza, G; Hollingsworth, M; Spanier, S; Yang, Z C; York, A; Asaadi, J; Eusebi, R; Gilmore, J; Gurrola, A; Kamon, T; Khotilovich, V; Montalvo, R; Nguyen, C N; Osipenkov, I; Pakhotin, Y; Pivarski, J; Safonov, A; Sengupta, S; Tatarinov, A; Toback, D; Weinberger, M; Akchurin, N; Bardak, C; Damgov, J; Jeong, C; Kovitanggoon, K; Lee, S W; Roh, Y; Sill, A; Volobouev, I; Wigmans, R; Yazgan, E; Appelt, E; Brownson, E; Engh, D; Florez, C; Gabella, W; Issah, M; Johns, W; Kurt, P; Maguire, C; Melo, A; Sheldon, P; Snook, B; Tuo, S; Velkovska, J; Arenton, M W; Balazs, M; Boutle, S; Cox, B; Francis, B; Hirosky, R; Ledovskoy, A; Lin, C; Neu, C; Yohay, R; Gollapinni, S; Harr, R; Karchin, P E; Lamichhane, P; Mattson, M; Milstène, C; Sakharov, A; Anderson, M; Bachtis, M; Bellinger, J N; Carlsmith, D; Dasu, S; Efron, J; Flood, K; Gray, L; Grogg, K S; Grothe, M; Hall-Wilton, R; Herndon, M; Klabbers, P; Klukas, J; Lanaro, A; Lazaridis, C; Leonard, J; Loveless, R; Mohapatra, A; Palmonari, F; Reeder, D; Ross, I; Savin, A; Smith, W H; Swanson, J; Weinberg, M

    2011-05-27

    A search for supersymmetry in the context of general gauge-mediated breaking with the lightest neutralino as the next-to-lightest supersymmetric particle and the gravitino as the lightest is presented. The data sample corresponds to an integrated luminosity of 36 pb(-1) recorded by the CMS experiment at the LHC. The search is performed by using events containing two or more isolated photons, at least one hadronic jet, and significant missing transverse energy. No excess of events at high missing transverse energy is observed. Upper limits on the signal cross section for general gauge-mediated supersymmetry between 0.3 and 1.1 pb at the 95% confidence level are determined for a range of squark, gluino, and neutralino masses, excluding supersymmetry parameter space that was inaccessible to previous experiments. © 2011 CERN, for the CMS Collaboration

  13. Meta‐analysis of test accuracy studies using imputation for partial reporting of multiple thresholds

    PubMed Central

    Deeks, J.J.; Martin, E.C.; Riley, R.D.

    2017-01-01

    Introduction For tests reporting continuous results, primary studies usually provide test performance at multiple but often different thresholds. This creates missing data when performing a meta‐analysis at each threshold. A standard meta‐analysis (no imputation [NI]) ignores such missing data. A single imputation (SI) approach was recently proposed to recover missing threshold results. Here, we propose a new method that performs multiple imputation of the missing threshold results using discrete combinations (MIDC). Methods The new MIDC method imputes missing threshold results by randomly selecting from the set of all possible discrete combinations which lie between the results for 2 known bounding thresholds. Imputed and observed results are then synthesised at each threshold. This is repeated multiple times, and the multiple pooled results at each threshold are combined using Rubin's rules to give final estimates. We compared the NI, SI, and MIDC approaches via simulation. Results Both imputation methods outperform the NI method in simulations. There was generally little difference in the SI and MIDC methods, but the latter was noticeably better in terms of estimating the between‐study variances and generally gave better coverage, due to slightly larger standard errors of pooled estimates. Given selective reporting of thresholds, the imputation methods also reduced bias in the summary receiver operating characteristic curve. Simulations demonstrate the imputation methods rely on an equal threshold spacing assumption. A real example is presented. Conclusions The SI and, in particular, MIDC methods can be used to examine the impact of missing threshold results in meta‐analysis of test accuracy studies. PMID:29052347

  14. Effects of Negative Emotions and Life Events on Women's Missed Miscarriage.

    PubMed

    Xing, Huilin; Luo, Yaping; Wang, Shouying

    2018-02-01

    To investigate the effects of negative emotions and life events on women's missed miscarriage. Overall, 214 women diagnosed with a missed miscarriage by prenatal examination from 2016-2017 in Xiamen Maternal and Child Health Care Hospital, Xiamen, China were selected as the observation group compared to 214 women as control group. The general data of the patients were investigated by self-programmed questionnaires. Zung Self-Rating Anxiety Scale, Center Epidemiological Studies Depression Scale; Life Events Scale for Pregnant Women were used conduct the study. General data, anxiety, depression and life events were compared between the two groups of patients, and statistically different factors were included in the multivariate Logistic regression analysis. There were statistically significant differences in the educational level, pre-pregnancy health status, planned pregnancy, pre-pregnancy or gestational gynecological inflammation and the initiative to obtain knowledge of prenatal and postnatal care between the two groups of pregnant women ( P <0.01); there were also statistically significant differences in score of life events, score of anxiety and score of depression between them ( P <0.01). The high educational level, good health status before pregnancy and the initiative to obtain the knowledge of prenatal and postnatal care were taken as the independent protective factors for the missed miscarriage in pregnant women, while life events, anxiety and depression were independent risk factors for it. Negative emotions and life events increase the risk of women's missed miscarriage, and the high educational level, good health status before pregnancy and the initiative to obtain the knowledge of prenatal and postnatal care reduce the risk of women's missed miscarriage.

  15. Potential value of health information exchange for people with epilepsy: crossover patterns and missing clinical data.

    PubMed

    Grinspan, Zachary M; Abramson, Erika L; Banerjee, Samprit; Kern, Lisa M; Kaushal, Rainu; Shapiro, Jason S

    2013-01-01

    For people with epilepsy, the potential value of health information exchange (HIE) is unknown. We reviewed two years of clinical encounters for 8055 people with epilepsy from seven Manhattan hospitals. We created network graphs illustrating crossover among these hospitals for multiple encounter types, and calculated a novel metric of care fragmentation: "encounters at risk for missing clinical data." Given two hospitals, a median of 109 [range 46 - 588] patients with epilepsy had visited both. Due to this crossover, recent, relevant clinical data may be missing at the time of care frequently (44.8% of ED encounters, 34.5% inpatient, 24.9% outpatient, and 23.2% radiology). Though a smaller percentage of outpatient encounters were at risk for missing data than ED encounters, the absolute number of outpatient encounters at risk was three times higher (14,579 vs. 5041). People with epilepsy may benefit from HIE. Future HIE initiatives should prioritize outpatient access.

  16. Finding the Missing Patients With Tuberculosis: Lessons Learned From Patient-Pathway Analyses in 5 Countries.

    PubMed

    Hanson, Christy; Osberg, Mike; Brown, Jessie; Durham, George; Chin, Daniel P

    2017-11-06

    Despite significant progress in diagnosis and treatment of tuberculosis over the past 2 decades, millions of patients with tuberculosis go unreported every year. The patient-pathway analysis (PPA) is designed to assess the alignment between tuberculosis care-seeking patterns and the availability of tuberculosis services. The PPA can help programs understand where they might find the missing patients with tuberculosis. This analysis aggregates and compares the PPAs from case studies in Kenya, Ethiopia, Indonesia, the Philippines, and Pakistan. Across the 5 countries, 24% of patients with tuberculosis initiated care seeking in a facility with tuberculosis diagnostic capacity. Forty-two percent of patients sought care at level 0 facilities, where there was generally no tuberculosis diagnostic capacity; another 42% of patients sought care at level 1 facilities, of which 39% had diagnostic capacity. Sixty-six percent of patients initially sought care in private facilities, which had considerably less tuberculosis diagnostic capacity than public facilities; only 7% of notified cases were from the private sector. The GeneXpert system was available in 14%-41% of level 2 facilities in the 3 countries for which there were data. Tuberculosis treatment capacity tracked closely with the availability of diagnostic capacity. There were substantial subnational differences in care-seeking patterns and service availability. The PPA can be a valuable planning and programming tool to ensure that diagnostic and treatment services are available to patients where they seek care. Patient-centered care will require closing the diagnostic gap and engaging the private sector. Extensive subnational differences in patient pathways to care call for differentiated approaches to patient-centered care. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America.

  17. Finding the Missing Patients With Tuberculosis: Lessons Learned From Patient-Pathway Analyses in 5 Countries

    PubMed Central

    Hanson, Christy; Osberg, Mike; Brown, Jessie; Durham, George; Chin, Daniel P

    2017-01-01

    Abstract Background Despite significant progress in diagnosis and treatment of tuberculosis over the past 2 decades, millions of patients with tuberculosis go unreported every year. The patient-pathway analysis (PPA) is designed to assess the alignment between tuberculosis care-seeking patterns and the availability of tuberculosis services. The PPA can help programs understand where they might find the missing patients with tuberculosis. Methods This analysis aggregates and compares the PPAs from case studies in Kenya, Ethiopia, Indonesia, the Philippines, and Pakistan. Results Across the 5 countries, 24% of patients with tuberculosis initiated care seeking in a facility with tuberculosis diagnostic capacity. Forty-two percent of patients sought care at level 0 facilities, where there was generally no tuberculosis diagnostic capacity; another 42% of patients sought care at level 1 facilities, of which 39% had diagnostic capacity. Sixty-six percent of patients initially sought care in private facilities, which had considerably less tuberculosis diagnostic capacity than public facilities; only 7% of notified cases were from the private sector. The GeneXpert system was available in 14%–41% of level 2 facilities in the 3 countries for which there were data. Tuberculosis treatment capacity tracked closely with the availability of diagnostic capacity. There were substantial subnational differences in care-seeking patterns and service availability. Discussion The PPA can be a valuable planning and programming tool to ensure that diagnostic and treatment services are available to patients where they seek care. Patient-centered care will require closing the diagnostic gap and engaging the private sector. Extensive subnational differences in patient pathways to care call for differentiated approaches to patient-centered care. PMID:29117351

  18. Testing treatment effect in schizophrenia clinical trials with heavy patient dropout using latent class growth mixture models.

    PubMed

    Kong, Fanhui; Chen, Yeh-Fong

    2016-07-01

    By examining the outcome trajectories of the dropout patients with different reasons in the schizophrenia trials, we note that although patients are recruited from the same protocol that have compatible baseline characteristics, they may respond differently even to the same treatment. Some patients show consistent improvement while others only have temporary relief. This creates different patient subpopulations characterized by their response and dropout patterns. At the same time, those who continue to improve seem to be more likely to complete the study while those who only experience temporary relief have a higher chance to drop out. Such phenomenon appears to be quite general in schizophrenia clinical trials. This simultaneous inhomogeneity both in patient response as well as dropout patterns creates a scenario of missing not at random and therefore results in biases when we use the statistical methods based on the missing at random assumption to test treatment efficacy. In this paper, we propose to use the latent class growth mixture model, which is a special case of the latent mixture model, to conduct the statistical analyses in such situation. This model allows us to take the inhomogeneity among subpopulations into consideration to make more accurate inferences on the treatment effect at any visit time. Comparing with the conventional statistical methods such as mixed-effects model for repeated measures, we demonstrate through simulations that the proposed latent mixture model approach gives better control on the Type I error rate in testing treatment effect. Published 2016. This article is a U.S. Government work and is in the public domain in the USA. Copyright © 2016 John Wiley & Sons, Ltd.

  19. Retrospective 70 y-spatial analysis of repeated vine mortality patterns using ancient aerial time series, Pléiades images and multi-source spatial and field data

    NASA Astrophysics Data System (ADS)

    Vaudour, E.; Leclercq, L.; Gilliot, J. M.; Chaignon, B.

    2017-06-01

    For any wine estate, there is a need to demarcate homogeneous within-vineyard zones ('terroirs') so as to manage grape production, which depends on vine biological condition. Until now, the studies performing digital zoning of terroirs have relied on recent spatial data and scant attention has been paid to ancient geoinformation likely to retrace past biological condition of vines and especially occurrence of vine mortality. Is vine mortality characterized by recurrent and specific patterns and if so, are these patterns related to terroir units and/or past landuse? This study aimed at performing a historical and spatial tracing of vine mortality patterns using a long time-series of aerial survey images (1947-2010), in combination with recent data: soil apparent electrical conductivity EM38 measurements, very high resolution Pléiades satellite images, and a detailed field survey. Within a 6 ha-estate in the Southern Rhone Valley, landuse and planting history were retraced and the map of missing vines frequency was constructed from the whole time series including a 2015-Pléiades panchromatic band. Within-field terroir units were obtained from a support vector machine classifier computed on the spectral bands and NDVI of Pléiades images, EM38 data and morphometric data. Repeated spatial patterns of missing vines were highlighted throughout several plantings, uprootings, and vine replacements, and appeared to match some within-field terroir units, being explained by their specific soil characteristics, vine/soil management choices and the past landuse of the 1940s. Missing vines frequency was spatially correlated with topsoil CaCO3 content, and negatively correlated with topsoil iron, clay, total N, organic C contents and NDVI. A retrospective spatio-temporal assessment of terroir therefore brings a renewed focus on some key parameters for maintaining a sustainable grape production.

  20. Statistical analysis and handling of missing data in cluster randomized trials: a systematic review.

    PubMed

    Fiero, Mallorie H; Huang, Shuang; Oren, Eyal; Bell, Melanie L

    2016-02-09

    Cluster randomized trials (CRTs) randomize participants in groups, rather than as individuals and are key tools used to assess interventions in health research where treatment contamination is likely or if individual randomization is not feasible. Two potential major pitfalls exist regarding CRTs, namely handling missing data and not accounting for clustering in the primary analysis. The aim of this review was to evaluate approaches for handling missing data and statistical analysis with respect to the primary outcome in CRTs. We systematically searched for CRTs published between August 2013 and July 2014 using PubMed, Web of Science, and PsycINFO. For each trial, two independent reviewers assessed the extent of the missing data and method(s) used for handling missing data in the primary and sensitivity analyses. We evaluated the primary analysis and determined whether it was at the cluster or individual level. Of the 86 included CRTs, 80 (93%) trials reported some missing outcome data. Of those reporting missing data, the median percent of individuals with a missing outcome was 19% (range 0.5 to 90%). The most common way to handle missing data in the primary analysis was complete case analysis (44, 55%), whereas 18 (22%) used mixed models, six (8%) used single imputation, four (5%) used unweighted generalized estimating equations, and two (2%) used multiple imputation. Fourteen (16%) trials reported a sensitivity analysis for missing data, but most assumed the same missing data mechanism as in the primary analysis. Overall, 67 (78%) trials accounted for clustering in the primary analysis. High rates of missing outcome data are present in the majority of CRTs, yet handling missing data in practice remains suboptimal. Researchers and applied statisticians should carry out appropriate missing data methods, which are valid under plausible assumptions in order to increase statistical power in trials and reduce the possibility of bias. Sensitivity analysis should be performed, with weakened assumptions regarding the missing data mechanism to explore the robustness of results reported in the primary analysis.

  1. Depression, Anxiety and Somatization in Women with War Missing Family Members

    PubMed Central

    Baraković, Devla; Avdibegović, Esmina; Sinanović, Osman

    2013-01-01

    Introduction: During the war circumstances, women and children are exposed to multiple traumatic experiences, one of which is an violent disappearance of a family member. Goal: The aim of this research was to establish the presence of symptoms of depression, anxiety and somatization in women in Bosnia and Herzegovina who have sought their war missing family members for 15 to 18 years. Subjects and Methods: The research was based on a sample of 120 women with war missing family member and 40 women without a war missing family member as a control group. For assessment of depression, anxiety and symptoms of somatization the self-rating Beck Depression Inventory (BDI), Hamilton Anxiety Rating Scale (HAM-A), Somatic Symptoms Index (SSI) questionnaire and a general questionnaire on the sociodemographic data and data on war missing family members were used. Results: A significantly higher intensity of symptoms of depression (p<0.001), anxiety (p<0.001) and somatization (p = 0.013) was present in women with, in comparison to women without a missing family member. In comparison of the kinship with the missing family members, statistically significantly higher intensity of symptoms of depression, anxiety and somatization was in women with a missing child (p<0.001) in comparison to other missing family members. Conclusion: A prolonged period of seeking, waiting and uncertainty of what happened in the war with the missing family member presents for those women a prolonged suffering manifested through depression, anxiety and symptoms of somatization. PMID:24167436

  2. Attrition Bias Related to Missing Outcome Data: A Longitudinal Simulation Study.

    PubMed

    Lewin, Antoine; Brondeel, Ruben; Benmarhnia, Tarik; Thomas, Frédérique; Chaix, Basile

    2018-01-01

    Most longitudinal studies do not address potential selection biases due to selective attrition. Using empirical data and simulating additional attrition, we investigated the effectiveness of common approaches to handle missing outcome data from attrition in the association between individual education level and change in body mass index (BMI). Using data from the two waves of the French RECORD Cohort Study (N = 7,172), we first examined how inverse probability weighting (IPW) and multiple imputation handled missing outcome data from attrition in the observed data (stage 1). Second, simulating additional missing data in BMI at follow-up under various missing-at-random scenarios, we quantified the impact of attrition and assessed how multiple imputation performed compared to complete case analysis and to a perfectly specified IPW model as a gold standard (stage 2). With the observed data in stage 1, we found an inverse association between individual education and change in BMI, with complete case analysis, as well as with IPW and multiple imputation. When we simulated additional attrition under a missing-at-random pattern (stage 2), the bias increased with the magnitude of selective attrition, and multiple imputation was useless to address it. Our simulations revealed that selective attrition in the outcome heavily biased the association of interest. The present article contributes to raising awareness that for missing outcome data, multiple imputation does not do better than complete case analysis. More effort is thus needed during the design phase to understand attrition mechanisms by collecting information on the reasons for dropout.

  3. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zhang, Jing, E-mail: jing.zhang2@duke.edu; Ghate, Sujata V.; Yoon, Sora C.

    Purpose: Mammography is the most widely accepted and utilized screening modality for early breast cancer detection. Providing high quality mammography education to radiology trainees is essential, since excellent interpretation skills are needed to ensure the highest benefit of screening mammography for patients. The authors have previously proposed a computer-aided education system based on trainee models. Those models relate human-assessed image characteristics to trainee error. In this study, the authors propose to build trainee models that utilize features automatically extracted from images using computer vision algorithms to predict likelihood of missing each mass by the trainee. This computer vision-based approach tomore » trainee modeling will allow for automatically searching large databases of mammograms in order to identify challenging cases for each trainee. Methods: The authors’ algorithm for predicting the likelihood of missing a mass consists of three steps. First, a mammogram is segmented into air, pectoral muscle, fatty tissue, dense tissue, and mass using automated segmentation algorithms. Second, 43 features are extracted using computer vision algorithms for each abnormality identified by experts. Third, error-making models (classifiers) are applied to predict the likelihood of trainees missing the abnormality based on the extracted features. The models are developed individually for each trainee using his/her previous reading data. The authors evaluated the predictive performance of the proposed algorithm using data from a reader study in which 10 subjects (7 residents and 3 novices) and 3 experts read 100 mammographic cases. Receiver operating characteristic (ROC) methodology was applied for the evaluation. Results: The average area under the ROC curve (AUC) of the error-making models for the task of predicting which masses will be detected and which will be missed was 0.607 (95% CI,0.564-0.650). This value was statistically significantly different from 0.5 (p < 0.0001). For the 7 residents only, the AUC performance of the models was 0.590 (95% CI,0.537-0.642) and was also significantly higher than 0.5 (p = 0.0009). Therefore, generally the authors’ models were able to predict which masses were detected and which were missed better than chance. Conclusions: The authors proposed an algorithm that was able to predict which masses will be detected and which will be missed by each individual trainee. This confirms existence of error-making patterns in the detection of masses among radiology trainees. Furthermore, the proposed methodology will allow for the optimized selection of difficult cases for the trainees in an automatic and efficient manner.« less

  4. Comparison of methods for dealing with missing values in the EPV-R.

    PubMed

    Paniagua, David; Amor, Pedro J; Echeburúa, Enrique; Abad, Francisco J

    2017-08-01

    The development of an effective instrument to assess the risk of partner violence is a topic of great social relevance. This study evaluates the scale of “Predicción del Riesgo de Violencia Grave Contra la Pareja” –Revisada– (EPV-R - Severe Intimate Partner Violence Risk Prediction Scale-Revised), a tool developed in Spain, which is facing the problem of how to treat the high rate of missing values, as is usual in this type of scale. First, responses to the EPV-R in a sample of 1215 male abusers who were reported to the police were used to analyze the patterns of occurrence of missing values, as well as the factor structure. Second, we analyzed the performance of various imputation methods using simulated data that emulates the missing data mechanism found in the empirical database. The imputation procedure originally proposed by the authors of the scale provides acceptable results, although the application of a method based on the Item Response Theory could provide greater accuracy and offers some additional advantages. Item Response Theory appears to be a useful tool for imputing missing data in this type of questionnaire.

  5. Exoatmospheric intercepts using zero effort miss steering for midcourse guidance

    NASA Astrophysics Data System (ADS)

    Newman, Brett

    The suitability of proportional navigation, or an equivalent zero effort miss formulation, for exatmospheric intercepts during midcourse guidance, followed by a ballistic coast to the endgame, is addressed. The problem is formulated in terms of relative motion in a general, three dimensional framework. The proposed guidance law for the commanded thrust vector orientation consists of the sum of two terms: (1) along the line of sight unit direction and (2) along the zero effort miss component perpendicular to the line of sight and proportional to the miss itself and a guidance gain. If the guidance law is to be suitable for longer range targeting applications with significant ballistic coasting after burnout, determination of the zero effort miss must account for the different gravitational accelerations experienced by each vehicle. The proposed miss determination techniques employ approximations for the true differential gravity effect and thus, are less accurate than a direct numerical propagation of the governing equations, but more accurate than a baseline determination, which assumes equal accelerations for both vehicles. Approximations considered are constant, linear, quadratic, and linearized inverse square models. Theoretical results are applied to a numerical engagement scenario and the resulting performance is evaluated in terms of the miss distances determined from nonlinear simulation.

  6. HS-SPME/GC analysis reveals the population variability of terpene contents in Juniperus communis needles.

    PubMed

    Filipowicz, Natalia; Madanecki, Piotr; Gołebiowski, Marek; Stepnowski, Piotr; Ochocka, J Renata

    2009-12-01

    Juniperus communis var. communis L. is an aromatic plant - typical boreal element of flora. In the extensive literature concerning J. communis, there is much data on the composition and the content of essential oil of needles and coneberries, but a detailed analysis of terpene distribution within and between populations is missing. A representative pool of 74 J. communis individuals originating from ten populations of Northern Poland was investigated in order to evaluate the intra- and interpopulational variability of the terpene pattern. Headspace solid-phase microextraction (HS-SPME) coupled with GC/MS and GC/FID was applied in achiral and enantioselective analysis. The majority of the samples (85%), despite different origin, were similar in the terpene pattern. High diversity of terpenes was observed within the populations and low diversity between them. High variation of enantiomeric composition was in accordance with large variation of individual compounds in general (achiral analysis). J. communis samples from Northern Poland could be distinguished by the alpha-pinene/sabinene ratio, and they were divided into three chemical races.

  7. Key Lessons from Performance of the U.S. EPA Endocrine Disruptor Screening Program (EDSP) Tier 1 Male and Female Pubertal Assays

    PubMed Central

    Stump, Donald G; O'Connor, John C; Lewis, Joseph M; Marty, M Sue

    2014-01-01

    The male and female pubertal assays, which are included in the U.S. Environmental Protection Agency's (EPA) Endocrine Disruptor Screening Program (EDSP) Tier 1 battery, can detect endocrine-active compounds operating by various modes of action. This article uses the collective experience of three laboratories to provide information on pubertal assay conduct, interlaboratory reproducibility, endpoint redundancy, and data interpretation. The various criteria used to select the maximum tolerated dose are described. A comparison of historical control data across laboratories confirmed reasonably good interlaboratory reproducibility. With a reliance on apical endpoints, interpretation of pubertal assay effects as specifically endocrine-mediated or secondary to other systemic effects can be problematic and mode of action may be difficult to discern. Across 21–23 data sets, relative liver weight, a nonspecific endocrine endpoint, was the most commonly affected endpoint in male and female assays. For endocrine endpoints, patterns of effects were generally seen; rarely was an endocrine-sensitive endpoint affected in isolation. In males, most frequently missed EPA-established performance criteria included mean weights for kidney and thyroid, and the coefficient of variation for age and body weight at preputial separation, seminal vesicle weight, and final body weight. In females, the frequently missed EPA-established performance criteria included mean adrenal weight and mean age at vaginal opening. To ensure specificity for endocrine effects, the pubertal assays should be interpreted using a weight-of-evidence approach as part of the entire EDSP battery. Based on the frequency with which certain performance criteria were missed, an EPA review of these criteria is warranted. PMID:24510766

  8. Weber's law, the magnitude effect and discrimination of sugar concentrations in nectar-feeding animals.

    PubMed

    Nachev, Vladislav; Stich, Kai Petra; Winter, York

    2013-01-01

    Weber's law quantifies the perception of difference between stimuli. For instance, it can explain why we are less likely to detect the removal of three nuts from a bowl if the bowl is full than if it is nearly empty. This is an example of the magnitude effect - the phenomenon that the subjective perception of a linear difference between a pair of stimuli progressively diminishes when the average magnitude of the stimuli increases. Although discrimination performances of both human and animal subjects in various sensory modalities exhibit the magnitude effect, results sometimes systematically deviate from the quantitative predictions based on Weber's law. An attempt to reformulate the law to better fit data from acoustic discrimination tasks has been dubbed the "near-miss to Weber's law". Here, we tested the gustatory discrimination performance of nectar-feeding bats (Glossophaga soricina), in order to investigate whether the original version of Weber's law accurately predicts choice behavior in a two-alternative forced choice task. As expected, bats either preferred the sweeter of the two options or showed no preference. In 4 out of 6 bats the near-miss to Weber's law provided a better fit and Weber's law underestimated the magnitude effect. In order to test the generality of this observation in nectar-feeders, we reviewed previously published data on bats, hummingbirds, honeybees, and bumblebees. In all groups of animals the near-miss to Weber's law provided better fits than Weber's law. Furthermore, whereas the magnitude effect was stronger than predicted by Weber's law in vertebrates, it was weaker than predicted in insects. Thus nectar-feeding vertebrates and insects seem to differ in how their choice behavior changes as sugar concentration is increased. We discuss the ecological and evolutionary implications of the observed patterns of sugar concentration discrimination.

  9. A Comparison of Factor Score Estimation Methods in the Presence of Missing Data: Reliability and an Application to Nicotine Dependence

    ERIC Educational Resources Information Center

    Estabrook, Ryne; Neale, Michael

    2013-01-01

    Factor score estimation is a controversial topic in psychometrics, and the estimation of factor scores from exploratory factor models has historically received a great deal of attention. However, both confirmatory factor models and the existence of missing data have generally been ignored in this debate. This article presents a simulation study…

  10. Descendant root volume varies as a function of root type: estimation of root biomass lost during uprooting in Pinus pinaster.

    PubMed

    Danjon, Frédéric; Caplan, Joshua S; Fortin, Mathieu; Meredieu, Céline

    2013-01-01

    Root systems of woody plants generally display a strong relationship between the cross-sectional area or cross-sectional diameter (CSD) of a root and the dry weight of biomass (DWd) or root volume (Vd) that has grown (i.e., is descendent) from a point. Specification of this relationship allows one to quantify root architectural patterns and estimate the amount of material lost when root systems are extracted from the soil. However, specifications of this relationship generally do not account for the fact that root systems are comprised of multiple types of roots. We assessed whether the relationship between CSD and Vd varies as a function of root type. Additionally, we sought to identify a more accurate and time-efficient method for estimating missing root volume than is currently available. We used a database that described the 3D root architecture of Pinus pinaster root systems (5, 12, or 19 years) from a stand in southwest France. We determined the relationship between CSD and Vd for 10,000 root segments from intact root branches. Models were specified that did and did not account for root type. The relationships were then applied to the diameters of 11,000 broken root ends to estimate the volume of missing roots. CSD was nearly linearly related to the square root of Vd, but the slope of the curve varied greatly as a function of root type. Sinkers and deep roots tapered rapidly, as they were limited by available soil depth. Distal shallow roots tapered gradually, as they were less limited spatially. We estimated that younger trees lost an average of 17% of root volume when excavated, while older trees lost 4%. Missing volumes were smallest in the central parts of root systems and largest in distal shallow roots. The slopes of the curves for each root type are synthetic parameters that account for differentiation due to genetics, soil properties, or mechanical stimuli. Accounting for this differentiation is critical to estimating root loss accurately.

  11. Descendant root volume varies as a function of root type: estimation of root biomass lost during uprooting in Pinus pinaster

    PubMed Central

    Danjon, Frédéric; Caplan, Joshua S.; Fortin, Mathieu; Meredieu, Céline

    2013-01-01

    Root systems of woody plants generally display a strong relationship between the cross-sectional area or cross-sectional diameter (CSD) of a root and the dry weight of biomass (DWd) or root volume (Vd) that has grown (i.e., is descendent) from a point. Specification of this relationship allows one to quantify root architectural patterns and estimate the amount of material lost when root systems are extracted from the soil. However, specifications of this relationship generally do not account for the fact that root systems are comprised of multiple types of roots. We assessed whether the relationship between CSD and Vd varies as a function of root type. Additionally, we sought to identify a more accurate and time-efficient method for estimating missing root volume than is currently available. We used a database that described the 3D root architecture of Pinus pinaster root systems (5, 12, or 19 years) from a stand in southwest France. We determined the relationship between CSD and Vd for 10,000 root segments from intact root branches. Models were specified that did and did not account for root type. The relationships were then applied to the diameters of 11,000 broken root ends to estimate the volume of missing roots. CSD was nearly linearly related to the square root of Vd, but the slope of the curve varied greatly as a function of root type. Sinkers and deep roots tapered rapidly, as they were limited by available soil depth. Distal shallow roots tapered gradually, as they were less limited spatially. We estimated that younger trees lost an average of 17% of root volume when excavated, while older trees lost 4%. Missing volumes were smallest in the central parts of root systems and largest in distal shallow roots. The slopes of the curves for each root type are synthetic parameters that account for differentiation due to genetics, soil properties, or mechanical stimuli. Accounting for this differentiation is critical to estimating root loss accurately. PMID:24167506

  12. Generalizing Effective Teaching Skills: The Missing Link in Teacher Preparation

    ERIC Educational Resources Information Center

    Scheeler, Mary Catherine

    2008-01-01

    A clear need to teach preservice teachers to generalize newly acquired teaching skills across time and settings has been well established in the literature. Few empirical studies exist that inform teacher educators on ways to promote generalization of teaching skills with beginning teachers, however. Programming for generalization continues to be…

  13. Prevalence of abnormalities in dental structure, position, and eruption pattern in a population of unilateral and bilateral cleft lip and palate patients.

    PubMed

    Tortora, Chiara; Meazzini, Maria C; Garattini, Giovanna; Brusati, Roberto

    2008-03-01

    To evaluate the dental characteristics of patients subjected to a protocol that included early secondary gingivoalveoloplasty (ESGAP). Panoramic radiographs of 87 patients with unilateral cleft lip and palate (UCLP) and 29 with bilateral cleft lip and palate (BCLP) were evaluated. Missing and supernumerary teeth were also quantified on the cleft and noncleft side and in the maxilla and mandible. Crown and root malformations and tooth rotations were quantified. A subsample in permanent dentition was extrapolated to analyze canine eruption patterns. A total of 48.8% of the UCLP patients presented with missing permanent lateral incisors in the cleft area and 6.1% contralaterally. A total of 4.9% presented with missing second maxillary premolars on the cleft site and 1.2% contralaterally. A total of 7.3% presented with supernumerary lateral incisors, and 45% of the BCLP cleft sites presented with missing lateral incisors, while 25% of the cleft sites presented second maxillary premolars agenesis. Five percent of the cleft sites presented with supernumerary lateral incisors. Evaluation of the subsample in permanent dentition showed that 15.5% had a canine retention and 4.4% of the canines had to be surgically exposed. A significant association was observed between canine inclination and retention but not with absence of the lateral incisor. The frequency of dental anomalies in this sample was similar to other cleft populations. As surgical trauma has been suggested to damage forming teeth, the results of this study indicated that ESGAP has no detrimental influence on subsequent dental development.

  14. Multi-task Gaussian process for imputing missing data in multi-trait and multi-environment trials.

    PubMed

    Hori, Tomoaki; Montcho, David; Agbangla, Clement; Ebana, Kaworu; Futakuchi, Koichi; Iwata, Hiroyoshi

    2016-11-01

    A method based on a multi-task Gaussian process using self-measuring similarity gave increased accuracy for imputing missing phenotypic data in multi-trait and multi-environment trials. Multi-environmental trial (MET) data often encounter the problem of missing data. Accurate imputation of missing data makes subsequent analysis more effective and the results easier to understand. Moreover, accurate imputation may help to reduce the cost of phenotyping for thinned-out lines tested in METs. METs are generally performed for multiple traits that are correlated to each other. Correlation among traits can be useful information for imputation, but single-trait-based methods cannot utilize information shared by traits that are correlated. In this paper, we propose imputation methods based on a multi-task Gaussian process (MTGP) using self-measuring similarity kernels reflecting relationships among traits, genotypes, and environments. This framework allows us to use genetic correlation among multi-trait multi-environment data and also to combine MET data and marker genotype data. We compared the accuracy of three MTGP methods and iterative regularized PCA using rice MET data. Two scenarios for the generation of missing data at various missing rates were considered. The MTGP performed a better imputation accuracy than regularized PCA, especially at high missing rates. Under the 'uniform' scenario, in which missing data arise randomly, inclusion of marker genotype data in the imputation increased the imputation accuracy at high missing rates. Under the 'fiber' scenario, in which missing data arise in all traits for some combinations between genotypes and environments, the inclusion of marker genotype data decreased the imputation accuracy for most traits while increasing the accuracy in a few traits remarkably. The proposed methods will be useful for solving the missing data problem in MET data.

  15. Language-Specific and Language-General Factors in Text Reading in Arabic: Evidence from the Missing Letter Effect

    ERIC Educational Resources Information Center

    Saady, Amany; Ibrahim, Raphiq; Eviatar, Zohar

    2015-01-01

    The goal of the present study was to extend the models explaining the missing-letter effect (MLE) to an additional language and orthography, and to test the role of phonology in silent reading in Arabic. We also examined orthographic effects such as letter position and letter shape, morphological effects such as pseudo-prefixes, and phonological…

  16. A Modified General Location Model for Noncompliance with Missing Data: Revisiting the New York City School Choice Scholarship Program Using Principal Stratification

    ERIC Educational Resources Information Center

    Jin, Hui; Barnard, John; Rubin, Donald B.

    2010-01-01

    Missing data, especially when coupled with noncompliance, are a challenge even in the setting of randomized experiments. Although some existing methods can address each complication, it can be difficult to handle both of them simultaneously. This is true in the example of the New York City School Choice Scholarship Program, where both the…

  17. Traffic speed data imputation method based on tensor completion.

    PubMed

    Ran, Bin; Tan, Huachun; Feng, Jianshuai; Liu, Ying; Wang, Wuhong

    2015-01-01

    Traffic speed data plays a key role in Intelligent Transportation Systems (ITS); however, missing traffic data would affect the performance of ITS as well as Advanced Traveler Information Systems (ATIS). In this paper, we handle this issue by a novel tensor-based imputation approach. Specifically, tensor pattern is adopted for modeling traffic speed data and then High accurate Low Rank Tensor Completion (HaLRTC), an efficient tensor completion method, is employed to estimate the missing traffic speed data. This proposed method is able to recover missing entries from given entries, which may be noisy, considering severe fluctuation of traffic speed data compared with traffic volume. The proposed method is evaluated on Performance Measurement System (PeMS) database, and the experimental results show the superiority of the proposed approach over state-of-the-art baseline approaches.

  18. Traffic Speed Data Imputation Method Based on Tensor Completion

    PubMed Central

    Ran, Bin; Feng, Jianshuai; Liu, Ying; Wang, Wuhong

    2015-01-01

    Traffic speed data plays a key role in Intelligent Transportation Systems (ITS); however, missing traffic data would affect the performance of ITS as well as Advanced Traveler Information Systems (ATIS). In this paper, we handle this issue by a novel tensor-based imputation approach. Specifically, tensor pattern is adopted for modeling traffic speed data and then High accurate Low Rank Tensor Completion (HaLRTC), an efficient tensor completion method, is employed to estimate the missing traffic speed data. This proposed method is able to recover missing entries from given entries, which may be noisy, considering severe fluctuation of traffic speed data compared with traffic volume. The proposed method is evaluated on Performance Measurement System (PeMS) database, and the experimental results show the superiority of the proposed approach over state-of-the-art baseline approaches. PMID:25866501

  19. Is Social Categorization the Missing Link Between Weak Central Coherence and Mental State Inference Abilities in Autism? Preliminary Evidence from a General Population Sample.

    PubMed

    Skorich, Daniel P; May, Adrienne R; Talipski, Louisa A; Hall, Marnie H; Dolstra, Anita J; Gash, Tahlia B; Gunningham, Beth H

    2016-03-01

    We explore the relationship between the 'theory of mind' (ToM) and 'central coherence' difficulties of autism. We introduce covariation between hierarchically-embedded categories and social information--at the local level, the global level, or at both levels simultaneously--within a category confusion task. We then ask participants to infer the mental state of novel category members, and measure participants' autism-spectrum quotient (AQ). Results reveal a positive relationship between AQ and the degree of local/global social categorization, which in turn predicts the pattern of mental state inferences. These results provide preliminary evidence for a causal relationship between central coherence and ToM abilities. Implications with regard to ToM processes, social categorization, intervention, and the development of a unified account of autism are discussed.

  20. The impact of loss to follow-up on hypothesis tests of the treatment effect for several statistical methods in substance abuse clinical trials.

    PubMed

    Hedden, Sarra L; Woolson, Robert F; Carter, Rickey E; Palesch, Yuko; Upadhyaya, Himanshu P; Malcolm, Robert J

    2009-07-01

    "Loss to follow-up" can be substantial in substance abuse clinical trials. When extensive losses to follow-up occur, one must cautiously analyze and interpret the findings of a research study. Aims of this project were to introduce the types of missing data mechanisms and describe several methods for analyzing data with loss to follow-up. Furthermore, a simulation study compared Type I error and power of several methods when missing data amount and mechanism varies. Methods compared were the following: Last observation carried forward (LOCF), multiple imputation (MI), modified stratified summary statistics (SSS), and mixed effects models. Results demonstrated nominal Type I error for all methods; power was high for all methods except LOCF. Mixed effect model, modified SSS, and MI are generally recommended for use; however, many methods require that the data are missing at random or missing completely at random (i.e., "ignorable"). If the missing data are presumed to be nonignorable, a sensitivity analysis is recommended.

  1. A review of the handling of missing longitudinal outcome data in clinical trials

    PubMed Central

    2014-01-01

    The aim of this review was to establish the frequency with which trials take into account missingness, and to discover what methods trialists use for adjustment in randomised controlled trials with longitudinal measurements. Failing to address the problems that can arise from missing outcome data can result in misleading conclusions. Missing data should be addressed as a means of a sensitivity analysis of the complete case analysis results. One hundred publications of randomised controlled trials with longitudinal measurements were selected randomly from trial publications from the years 2005 to 2012. Information was extracted from these trials, including whether reasons for dropout were reported, what methods were used for handing the missing data, whether there was any explanation of the methods for missing data handling, and whether a statistician was involved in the analysis. The main focus of the review was on missing data post dropout rather than missing interim data. Of all the papers in the study, 9 (9%) had no missing data. More than half of the papers included in the study failed to make any attempt to explain the reasons for their choice of missing data handling method. Of the papers with clear missing data handling methods, 44 papers (50%) used adequate methods of missing data handling, whereas 30 (34%) of the papers used missing data methods which may not have been appropriate. In the remaining 17 papers (19%), it was difficult to assess the validity of the methods used. An imputation method was used in 18 papers (20%). Multiple imputation methods were introduced in 1987 and are an efficient way of accounting for missing data in general, and yet only 4 papers used these methods. Out of the 18 papers which used imputation, only 7 displayed the results as a sensitivity analysis of the complete case analysis results. 61% of the papers that used an imputation explained the reasons for their chosen method. Just under a third of the papers made no reference to reasons for missing outcome data. There was little consistency in reporting of missing data within longitudinal trials. PMID:24947664

  2. Do missing data influence the accuracy of divergence-time estimation with BEAST?

    PubMed

    Zheng, Yuchi; Wiens, John J

    2015-04-01

    Time-calibrated phylogenies have become essential to evolutionary biology. A recurrent and unresolved question for dating analyses is whether genes with missing data cells should be included or excluded. This issue is particularly unclear for the most widely used dating method, the uncorrelated lognormal approach implemented in BEAST. Here, we test the robustness of this method to missing data. We compare divergence-time estimates from a nearly complete dataset (20 nuclear genes for 32 species of squamate reptiles) to those from subsampled matrices, including those with 5 or 2 complete loci only and those with 5 or 8 incomplete loci added. In general, missing data had little impact on estimated dates (mean error of ∼5Myr per node or less, given an overall age of ∼220Myr in squamates), even when 80% of sampled genes had 75% missing data. Mean errors were somewhat higher when all genes were 75% incomplete (∼17Myr). However, errors increased dramatically when only 2 of 9 fossil calibration points were included (∼40Myr), regardless of missing data. Overall, missing data (and even numbers of genes sampled) may have only minor impacts on the accuracy of divergence dating with BEAST, relative to the dramatic effects of fossil calibrations. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. A novel complete-case analysis to determine statistical significance between treatments in an intention-to-treat population of randomized clinical trials involving missing data.

    PubMed

    Liu, Wei; Ding, Jinhui

    2018-04-01

    The application of the principle of the intention-to-treat (ITT) to the analysis of clinical trials is challenged in the presence of missing outcome data. The consequences of stopping an assigned treatment in a withdrawn subject are unknown. It is difficult to make a single assumption about missing mechanisms for all clinical trials because there are complicated reactions in the human body to drugs due to the presence of complex biological networks, leading to data missing randomly or non-randomly. Currently there is no statistical method that can tell whether a difference between two treatments in the ITT population of a randomized clinical trial with missing data is significant at a pre-specified level. Making no assumptions about the missing mechanisms, we propose a generalized complete-case (GCC) analysis based on the data of completers. An evaluation of the impact of missing data on the ITT analysis reveals that a statistically significant GCC result implies a significant treatment effect in the ITT population at a pre-specified significance level unless, relative to the comparator, the test drug is poisonous to the non-completers as documented in their medical records. Applications of the GCC analysis are illustrated using literature data, and its properties and limits are discussed.

  4. Cambro-ordovician sea-level fluctuations and sequence boundaries: The missing record and the evolution of new taxa

    USGS Publications Warehouse

    Lehnert, O.; Miller, J.F.; Leslie, Stephen A.; Repetski, J.E.; Ethington, Raymond L.

    2005-01-01

    The evolution of early Palaeozoic conodont faunas shows a clear connection to sea-level changes. One way that this connection manifests itself is that thick successions of carbonates are missing beneath major sequence boundaries due to karstification and erosion. From this observation arises the question of how many taxa have been lost from different conodont lineages in these incomplete successions. Although many taxa suffered extinction due to the environmental stresses associated with falling sea-levels, some must have survived in these extreme conditions. The number of taxa missing in the early Palaeozoic tropics always will be unclear, but it will be even more difficult to evaluate the missing record in detrital successions of higher latitudes. A common pattern in the evolution of Cambrian-Ordovician conodont lineages is appearances of new species at sea-level rises and disappearances at sea-level drops. This simple picture can be complicated by intervals that consistently have no representatives of a particular lineage, even after extensive sampling of the most complete sections. Presumably the lineages survived in undocumented refugia. In this paper, we give examples of evolution in Cambrian-Ordovician shallowmarine conodont faunas and highlight problems of undiscovered or truly missing segments of lineages. ?? The Palaeontological Association.

  5. Decoupled temporal patterns of evolution and ecology in two post-Paleozoic clades

    NASA Technical Reports Server (NTRS)

    McKinney, F. K.; Lidgard, S.; Sepkoski, J. J. Jr; Taylor, P. D.

    1998-01-01

    Counts of taxonomic diversity are the prevailing standards for documenting large-scale patterns of evolution in the fossil record. However, the secular pattern of relative ecological importance between the bryozoan clades Cyclostomata and Cheilostomata is not reflected fully in compilations of generic diversity or within-fauna species richness, and the delayed ecological recovery of the Cheilostomata after the mass extinction at the Cretaceous-Tertiary boundary is missed entirely. These observations demonstrate that evolutionary success and ecological dominance can be decoupled and profoundly different, even over tens of millions of years.

  6. An interference account of the missing-VP effect

    PubMed Central

    Häussler, Jana; Bader, Markus

    2015-01-01

    Sentences with doubly center-embedded relative clauses in which a verb phrase (VP) is missing are sometimes perceived as grammatical, thus giving rise to an illusion of grammaticality. In this paper, we provide a new account of why missing-VP sentences, which are both complex and ungrammatical, lead to an illusion of grammaticality, the so-called missing-VP effect. We propose that the missing-VP effect in particular, and processing difficulties with multiply center-embedded clauses more generally, are best understood as resulting from interference during cue-based retrieval. When processing a sentence with double center-embedding, a retrieval error due to interference can cause the verb of an embedded clause to be erroneously attached into a higher clause. This can lead to an illusion of grammaticality in the case of missing-VP sentences and to processing complexity in the case of complete sentences with double center-embedding. Evidence for an interference account of the missing-VP effect comes from experiments that have investigated the missing-VP effect in German using a speeded grammaticality judgments procedure. We review this evidence and then present two new experiments that show that the missing-VP effect can be found in German also with less restricting procedures. One experiment was a questionnaire study which required grammaticality judgments from participants without imposing any time constraints. The second experiment used a self-paced reading procedure and did not require any judgments. Both experiments confirm the prior findings of missing-VP effects in German and also show that the missing-VP effect is subject to a primacy effect as known from the memory literature. Based on this evidence, we argue that an account of missing-VP effects in terms of interference during cue-based retrieval is superior to accounts in terms of limited memory resources or in terms of experience with embedded structures. PMID:26136698

  7. Assessing written communication during interhospital transfers of emergency general surgery patients.

    PubMed

    Harl, Felicity N R; Saucke, Megan C; Greenberg, Caprice C; Ingraham, Angela M

    2017-06-15

    Poor communication causes fragmented care. Studies of transitions of care within a hospital and on discharge suggest significant communication deficits. Communication during transfers between hospitals has not been well studied. We assessed the written communication provided during interhospital transfers of emergency general surgery patients. We hypothesized that patients are transferred with incomplete documentation from referring facilities. We performed a retrospective review of written communication provided during interhospital transfers to our emergency department (ED) from referring EDs for emergency general surgical evaluation between January 1, 2014 and January 1, 2016. Elements of written communication were abstracted from referring facility documents scanned into the medical record using a standardized abstraction protocol. Descriptive statistics summarized the information communicated. A total of 129 patients met inclusion criteria. 87.6% (n = 113) of charts contained referring hospital documents. 42.5% (n = 48) were missing history and physicals. Diagnoses were missing in 9.7% (n = 11). Ninety-one computed tomography scans were performed; among 70 with reads, final reads were absent for 70.0% (n = 49). 45 ultrasounds and x-rays were performed; among 27 with reads, final reads were missing for 80.0% (n = 36). Reasons for transfer were missing in 18.6% (n = 21). Referring hospital physicians outside the ED were consulted in 32.7% (n = 37); consultants' notes were absent in 89.2% (n = 33). In 12.4% (n = 14), referring documents arrived after the patient's ED arrival and were not part of the original documentation provided. This study documents that information important to patient care is often missing in the written communication provided during interhospital transfers. This gap affords a foundation for standardizing provider communication during interhospital transfers. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Exemplar-based inpainting as a solution to the missing wedge problem in electron tomography.

    PubMed

    Trampert, Patrick; Wang, Wu; Chen, Delei; Ravelli, Raimond B G; Dahmen, Tim; Peters, Peter J; Kübel, Christian; Slusallek, Philipp

    2018-04-21

    A new method for dealing with incomplete projection sets in electron tomography is proposed. The approach is inspired by exemplar-based inpainting techniques in image processing and heuristically generates data for missing projection directions. The method has been extended to work on three dimensional data. In general, electron tomography reconstructions suffer from elongation artifacts along the beam direction. These artifacts can be seen in the corresponding Fourier domain as a missing wedge. The new method synthetically generates projections for these missing directions with the help of a dictionary based approach that is able to convey both structure and texture at the same time. It constitutes a preprocessing step that can be combined with any tomographic reconstruction algorithm. The new algorithm was applied to phantom data, to a real electron tomography data set taken from a catalyst, as well as to a real dataset containing solely colloidal gold particles. Visually, the synthetic projections, reconstructions, and corresponding Fourier power spectra showed a decrease of the typical missing wedge artifacts. Quantitatively, the inpainting method is capable to reduce missing wedge artifacts and improves tomogram quality with respect to full width half maximum measurements. Copyright © 2018. Published by Elsevier B.V.

  9. The Skillings-Mack test (Friedman test when there are missing data).

    PubMed

    Chatfield, Mark; Mander, Adrian

    2009-04-01

    The Skillings-Mack statistic (Skillings and Mack, 1981, Technometrics 23: 171-177) is a general Friedman-type statistic that can be used in almost any block design with an arbitrary missing-data structure. The missing data can be either missing by design, for example, an incomplete block design, or missing completely at random. The Skillings-Mack test is equivalent to the Friedman test when there are no missing data in a balanced complete block design, and the Skillings-Mack test is equivalent to the test suggested in Durbin (1951, British Journal of Psychology, Statistical Section 4: 85-90) for a balanced incomplete block design. The Friedman test was implemented in Stata by Goldstein (1991, Stata Technical Bulletin 3: 26-27) and further developed in Goldstein (2005, Stata Journal 5: 285). This article introduces the skilmack command, which performs the Skillings-Mack test.The skilmack command is also useful when there are many ties or equal ranks (N.B. the Friedman statistic compared with the chi(2) distribution will give a conservative result), as well as for small samples; appropriate results can be obtained by simulating the distribution of the test statistic under the null hypothesis.

  10. Integrated built-in-test false and missed alarms reduction based on forward infinite impulse response & recurrent finite impulse response dynamic neural networks

    NASA Astrophysics Data System (ADS)

    Cui, Yiqian; Shi, Junyou; Wang, Zili

    2017-11-01

    Built-in tests (BITs) are widely used in mechanical systems to perform state identification, whereas the BIT false and missed alarms cause trouble to the operators or beneficiaries to make correct judgments. Artificial neural networks (ANN) are previously used for false and missed alarms identification, which has the features such as self-organizing and self-study. However, these ANN models generally do not incorporate the temporal effect of the bottom-level threshold comparison outputs and the historical temporal features are not fully considered. To improve the situation, this paper proposes a new integrated BIT design methodology by incorporating a novel type of dynamic neural networks (DNN) model. The new DNN model is termed as Forward IIR & Recurrent FIR DNN (FIRF-DNN), where its component neurons, network structures, and input/output relationships are discussed. The condition monitoring false and missed alarms reduction implementation scheme based on FIRF-DNN model is also illustrated, which is composed of three stages including model training, false and missed alarms detection, and false and missed alarms suppression. Finally, the proposed methodology is demonstrated in the application study and the experimental results are analyzed.

  11. Missed opportunities for diagnosis: lessons learned from diagnostic errors in primary care.

    PubMed

    Goyder, Clare R; Jones, Caroline H D; Heneghan, Carl J; Thompson, Matthew J

    2015-12-01

    Because of the difficulties inherent in diagnosis in primary care, it is inevitable that diagnostic errors will occur. However, despite the important consequences associated with diagnostic errors and their estimated high prevalence, teaching and research on diagnostic error is a neglected area. To ascertain the key learning points from GPs' experiences of diagnostic errors and approaches to clinical decision making associated with these. Secondary analysis of 36 qualitative interviews with GPs in Oxfordshire, UK. Two datasets of semi-structured interviews were combined. Questions focused on GPs' experiences of diagnosis and diagnostic errors (or near misses) in routine primary care and out of hours. Interviews were audiorecorded, transcribed verbatim, and analysed thematically. Learning points include GPs' reliance on 'pattern recognition' and the failure of this strategy to identify atypical presentations; the importance of considering all potentially serious conditions using a 'restricted rule out' approach; and identifying and acting on a sense of unease. Strategies to help manage uncertainty in primary care were also discussed. Learning from previous examples of diagnostic errors is essential if these events are to be reduced in the future and this should be incorporated into GP training. At a practice level, learning points from experiences of diagnostic errors should be discussed more frequently; and more should be done to integrate these lessons nationally to understand and characterise diagnostic errors. © British Journal of General Practice 2015.

  12. Oral health effects, brushing habits and management of methamphetamine users for the general dental practitioner.

    PubMed

    Smit, D A; Naidoo, S

    2015-05-08

    Methamphetamine is a synthetic drug commonly abused in South Africa and is highly addictive. Users have a higher prevalence of dental caries compared to non-users and the classical caries pattern found in methamphetamine users is termed 'meth mouth'. The increased consumption of soft drinks and the absence of saliva are the main risk factors for 'meth mouth'. To determine the oral health status of individuals using methamphetamine. A cross-sectional study was conducted on a convenience sample of 308 self-reported methamphetamine users at 22 specialised substance addiction treatment centres in the Western Cape, South Africa. There was a significant difference in tooth brushing frequency when using methamphetamine (p = 0.0000022; χ(2) = 23.84; OR = 3.25). The mean decayed, missing and filled teeth score was ten and there was an association between the mean number of decayed teeth and the duration of drug addiction (p = 0.0071; χ(2) = 12.07). Users who were using methamphetamine for less than four years had fewer missing teeth compared to those who were using methamphetamine for more than four years. When methamphetamine abuse is detected, the dentist can play a key role in early management of drug addiction by referring the patient to specialised substance addiction treatment centres. In addition, by restoring the dental appearance, users may regain their self-esteem and improve their oral health quality of life.

  13. Adaptive self-organization in the embryo: its importance to adult anatomy and to tissue engineering.

    PubMed

    Davies, Jamie A

    2018-04-01

    The anatomy of healthy humans shows much minor variation, and twin-studies reveal at least some of this variation cannot be explained genetically. A plausible explanation is that fine-scale anatomy is not specified directly in a genetic programme, but emerges from self-organizing behaviours of cells that, for example, place a new capillary where it happens to be needed to prevent local hypoxia. Self-organizing behaviour can be identified by manipulating growing tissues (e.g. putting them under a spatial constraint) and observing an adaptive change that conserves the character of the normal tissue while altering its precise anatomy. Self-organization can be practically useful in tissue engineering but it is limited; generally, it is good for producing realistic small-scale anatomy but large-scale features will be missing. This is because self-organizing organoids miss critical symmetry-breaking influences present in the embryo: simulating these artificially, for example, with local signal sources, makes anatomy realistic even at large scales. A growing understanding of the mechanisms of self-organization is now allowing synthetic biologists to take their first tentative steps towards constructing artificial multicellular systems that spontaneously organize themselves into patterns, which may soon be extended into three-dimensional shapes. © 2017 The Authors Journal of Anatomy published by John Wiley & Sons Ltd on behalf of Anatomical Society.

  14. Testing for biases in selection on avian reproductive traits and partitioning direct and indirect selection using quantitative genetic models.

    PubMed

    Reed, Thomas E; Gienapp, Phillip; Visser, Marcel E

    2016-10-01

    Key life history traits such as breeding time and clutch size are frequently both heritable and under directional selection, yet many studies fail to document microevolutionary responses. One general explanation is that selection estimates are biased by the omission of correlated traits that have causal effects on fitness, but few valid tests of this exist. Here, we show, using a quantitative genetic framework and six decades of life-history data on two free-living populations of great tits Parus major, that selection estimates for egg-laying date and clutch size are relatively unbiased. Predicted responses to selection based on the Robertson-Price Identity were similar to those based on the multivariate breeder's equation (MVBE), indicating that unmeasured covarying traits were not missing from the analysis. Changing patterns of phenotypic selection on these traits (for laying date, linked to climate change) therefore reflect changing selection on breeding values, and genetic constraints appear not to limit their independent evolution. Quantitative genetic analysis of correlational data from pedigreed populations can be a valuable complement to experimental approaches to help identify whether apparent associations between traits and fitness are biased by missing traits, and to parse the roles of direct versus indirect selection across a range of environments. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

  15. Retracing recurring vine mortality patterns over a long duration: case study of a Mediterranean viticultural estate

    NASA Astrophysics Data System (ADS)

    Vaudour, Emmanuelle; Leclercq, Léa; Gilliot, Jean-Marc; Chaignon, Benoît

    2017-04-01

    This study was aimed at performing both long term historical and spatial tracing, focusing on the vine mortality patterns and their temporal repetition, across a 6 ha-farm, "Domaine des Chauvets", mainly planted with rainfed black Grenache and Syrah varieties in the Southern Rhone Valley in France. In this estate of long-standing wine-growing history, were mortality patterns randomly distributed or were they related to soil or historical management? Along with soil parameters, soil surface condition, vine biological parameters including vigour, presence of diseases, stock-unearthing were collected in the field at a total of 112 sampling locations. A total of 25 aerial photographs in digitized format from the French National Institute of Geographic and Forest Information (IGN) were examined over the 1947-2010 period, of which 7 were retained for further rectification and processing. This dataset was used to retrace the landuse and planting history for each plot, and then extract the frequency of missing vines. Within-field terroir units were demarcated using support vector machine classification of a set of present-day very high resolution data, including soil apparent electrical conductivity EM38 maps and very high resolution Pléiades satellite images of May 2014 and July 2015. Field and recent data revealed important soil erosion rates which are likely to ruin terroir sustainability and pointed out those units for which soil restoration practices are urgently needed, while the temporal dataset exhibited a repeated spatial pattern of missing vines, throughout several plantings, uprootings, and vine replacements. The frequency of missing vines was related to within-field terroir units and also to past landuse, particularly forest or orchard dating back the 1940s, and current soil organic carbon content. This brings renewed questions about the determinism of vine decline, suggesting contribution of soil degradation processes.

  16. Estimating monthly streamflow values by cokriging

    USGS Publications Warehouse

    Solow, A.R.; Gorelick, S.M.

    1986-01-01

    Cokriging is applied to estimation of missing monthly streamflow values in three records from gaging stations in west central Virginia. Missing values are estimated from optimal consideration of the pattern of auto- and cross-correlation among standardized residual log-flow records. Investigation of the sensitivity of estimation to data configuration showed that when observations are available within two months of a missing value, estimation is improved by accounting for correlation. Concurrent and lag-one observations tend to screen the influence of other available observations. Three models of covariance structure in residual log-flow records are compared using cross-validation. Models differ in how much monthly variation they allow in covariance. Precision of estimation, reflected in mean squared error (MSE), proved to be insensitive to this choice. Cross-validation is suggested as a tool for choosing an inverse transformation when an initial nonlinear transformation is applied to flow values. ?? 1986 Plenum Publishing Corporation.

  17. Addressing the Challenges of Obtaining Functional Outcomes in Traumatic Brain Injury Research: Missing Data Patterns, Timing of Follow-Up, and Three Prognostic Models

    PubMed Central

    Morrison, Laurie J.; Devlin, Sean M.; Bulger, Eileen M.; Brasel, Karen J.; Sheehan, Kellie; Minei, Joseph P.; Kerby, Jeffrey D.; Tisherman, Samuel A.; Rizoli, Sandro; Karmy-Jones, Riyad; van Heest, Rardi; Newgard, Craig D.

    2014-01-01

    Abstract Traumatic brain injury (TBI) is common and debilitating. Randomized trials of interventions for TBI ideally assess effectiveness by using long-term functional neurological outcomes, but such outcomes are difficult to obtain and costly. If there is little change between functional status at hospital discharge versus 6 months, then shorter-term outcomes may be adequate for use in future clinical trials. Using data from a previously published multi-center, randomized, placebo-controlled TBI clinical trial, we evaluated patterns of missing outcome data, changes in functional status between hospital discharge and 6 months, and three prognostic models to predict long-term functional outcome from covariates available at hospital discharge (functional measures, demographics, and injury characteristics). The Resuscitation Outcomes Consortium Hypertonic Saline trial enrolled 1282 TBI patients, obtaining the primary outcome of 6-month Glasgow Outcome Score Extended (GOSE) for 85% of patients, but missing the primary outcome for the remaining 15%. Patients with missing outcomes had less-severe injuries, higher neurological function at discharge (GOSE), and shorter hospital stays than patients whose GOSE was obtained. Of 1066 (83%) patients whose GOSE was obtained both at hospital discharge and at 6-months, 71% of patients had the same dichotomized functional status (severe disability/death vs. moderate/no disability) after 6 months as at discharge, 28% had an improved functional status, and 1% had worsened. Performance was excellent (C-statistic between 0.88 and 0.91) for all three prognostic models and calibration adequate for two models (p values, 0.22 and 0.85). Our results suggest that multiple imputation of the standard 6-month GOSE may be reasonable in TBI research when the primary outcome cannot be obtained through other means. PMID:24552494

  18. Addressing the challenges of obtaining functional outcomes in traumatic brain injury research: missing data patterns, timing of follow-up, and three prognostic models.

    PubMed

    Zelnick, Leila R; Morrison, Laurie J; Devlin, Sean M; Bulger, Eileen M; Brasel, Karen J; Sheehan, Kellie; Minei, Joseph P; Kerby, Jeffrey D; Tisherman, Samuel A; Rizoli, Sandro; Karmy-Jones, Riyad; van Heest, Rardi; Newgard, Craig D

    2014-06-01

    Traumatic brain injury (TBI) is common and debilitating. Randomized trials of interventions for TBI ideally assess effectiveness by using long-term functional neurological outcomes, but such outcomes are difficult to obtain and costly. If there is little change between functional status at hospital discharge versus 6 months, then shorter-term outcomes may be adequate for use in future clinical trials. Using data from a previously published multi-center, randomized, placebo-controlled TBI clinical trial, we evaluated patterns of missing outcome data, changes in functional status between hospital discharge and 6 months, and three prognostic models to predict long-term functional outcome from covariates available at hospital discharge (functional measures, demographics, and injury characteristics). The Resuscitation Outcomes Consortium Hypertonic Saline trial enrolled 1282 TBI patients, obtaining the primary outcome of 6-month Glasgow Outcome Score Extended (GOSE) for 85% of patients, but missing the primary outcome for the remaining 15%. Patients with missing outcomes had less-severe injuries, higher neurological function at discharge (GOSE), and shorter hospital stays than patients whose GOSE was obtained. Of 1066 (83%) patients whose GOSE was obtained both at hospital discharge and at 6-months, 71% of patients had the same dichotomized functional status (severe disability/death vs. moderate/no disability) after 6 months as at discharge, 28% had an improved functional status, and 1% had worsened. Performance was excellent (C-statistic between 0.88 and 0.91) for all three prognostic models and calibration adequate for two models (p values, 0.22 and 0.85). Our results suggest that multiple imputation of the standard 6-month GOSE may be reasonable in TBI research when the primary outcome cannot be obtained through other means.

  19. Rural settlements transition (RST) in a suburban area of metropolis: Internal structure perspectives.

    PubMed

    Ma, Wenqiu; Jiang, Guanghui; Wang, Deqi; Li, Wenqing; Guo, Hongquan; Zheng, Qiuyue

    2018-02-15

    Rural settlements transition (RST) is one of the most significant indices for understanding the phenomena of rural reconstruction and urban-rural transformation in China. However, a systematic overview of RST is missing, and there is a lack of evidence regarding its characteristics from the internal structure perspectives. In this paper, we systematically explore the RST regarding spatio-temporal change characteristics of internal structure, patterns and impacts on rural environment and development by using practical survey internal land-use data from 2005 to 2015. The results show that the temporal change characteristics of the internal structure of rural settlements demonstrate a tendency for housing land to decrease and other land-use types to increase. The spatial change characteristics reveal that the structure inclines to more complexity and diversity from an exurban area to an urban-rural fringe area. Based on this finding, we identify that rapid development of rural industrialization, more agglomerate and effective industrial land-use, and improved public infrastructure construction are the general RST patterns. Spatially, there exists a physical decay pattern in the exurban area, thereby resulting in the hollowing-out of rural industries and of the population. In addition, the extensive and disorderly pattern in the suburban area causes low efficiency output and serious environmental pollution. The RST pattern in the urban hinterland promoted the "men-environment" compatible development. The study concludes that regional differentiation in patterns and impacts are significant in the process of RST. Future adaptive strategies for rural settlements adjustment should be conducted according to regional characteristics, including socio-economic status, physical geography condition and economic location to improve the rural environmental sustainability. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. GenomewidePDB 2.0: A Newly Upgraded Versatile Proteogenomic Database for the Chromosome-Centric Human Proteome Project.

    PubMed

    Jeong, Seul-Ki; Hancock, William S; Paik, Young-Ki

    2015-09-04

    Since the launch of the Chromosome-centric Human Proteome Project (C-HPP) in 2012, the number of "missing" proteins has fallen to 2932, down from ∼5932 since the number was first counted in 2011. We compared the characteristics of missing proteins with those of already annotated proteins with respect to transcriptional expression pattern and the time periods in which newly identified proteins were annotated. We learned that missing proteins commonly exhibit lower levels of transcriptional expression and less tissue-specific expression compared with already annotated proteins. This makes it more difficult to identify missing proteins as time goes on. One of the C-HPP goals is to identify alternative spliced product of proteins (ASPs), which are usually difficult to find by shot-gun proteomic methods due to their sequence similarities with the representative proteins. To resolve this problem, it may be necessary to use a targeted proteomics approach (e.g., selected and multiple reaction monitoring [S/MRM] assays) and an innovative bioinformatics platform that enables the selection of target peptides for rarely expressed missing proteins or ASPs. Given that the success of efforts to identify missing proteins may rely on more informative public databases, it was necessary to upgrade the available integrative databases. To this end, we attempted to improve the features and utility of GenomewidePDB by integrating transcriptomic information (e.g., alternatively spliced transcripts), annotated peptide information, and an advanced search interface that can find proteins of interest when applying a targeted proteomics strategy. This upgraded version of the database, GenomewidePDB 2.0, may not only expedite identification of the remaining missing proteins but also enhance the exchange of information among the proteome community. GenomewidePDB 2.0 is available publicly at http://genomewidepdb.proteomix.org/.

  1. Quantification of missing prescriptions in commercial claims databases: results of a cohort study.

    PubMed

    Cepeda, Maria Soledad; Fife, Daniel; Denarié, Michel; Bradford, Dan; Roy, Stephanie; Yuan, Yingli

    2017-04-01

    This study aims to quantify the magnitude of missed dispensings in commercial claims databases. A retrospective cohort study has been used linking PharMetrics, a commercial claims database, to a prescription database (LRx) that captures pharmacy dispensings independently of payment method, including cash transactions. We included adults with dispensings for opioids, diuretics, antiplatelet medications, or anticoagulants. To determine the degree of capture of dispensings, we calculated the number of subjects with the following: (1) same number of dispensings in both databases; (2) at least one dispensing, but not all dispensings, missed in PharMetrics; and (3) all dispensings missing in PharMetrics. Similar analyses were conducted using dispensings as the unit of analysis. To assess whether a dispensing in LRx was in PharMetrics, the dispensing in PharMetrics had to be for the same medication class and within ±7 days in LRx. A total of 1 426 498 subjects were included. Overall, 68% of subjects had the same number of dispensings in both databases. In 13% of subjects, PharMetrics identified ≥1 dispensing but also missed ≥1 dispensing. In 19% of the subjects, PharMetrics missed all the dispensings. Taking dispensings as the unit of analysis, 25% of the dispensings present in LRx were not captured in PharMetrics. These patterns were similar across all four classes of medications. Of the dispensings missing in PharMetrics, 48% involved a subject who had >1 health insurance plan. Commercial claims databases provide an incomplete picture of all prescriptions dispensed to patients. The lack of capture goes beyond cash transactions and potentially introduces substantial misclassification bias. © 2017 The Authors. Pharmacoepidemiology & Drug Safety Published by John Wiley & Sons Ltd. © 2017 The Authors. Pharmacoepidemiology & Drug Safety Published by John Wiley & Sons Ltd.

  2. Multiple imputation for handling missing outcome data when estimating the relative risk.

    PubMed

    Sullivan, Thomas R; Lee, Katherine J; Ryan, Philip; Salter, Amy B

    2017-09-06

    Multiple imputation is a popular approach to handling missing data in medical research, yet little is known about its applicability for estimating the relative risk. Standard methods for imputing incomplete binary outcomes involve logistic regression or an assumption of multivariate normality, whereas relative risks are typically estimated using log binomial models. It is unclear whether misspecification of the imputation model in this setting could lead to biased parameter estimates. Using simulated data, we evaluated the performance of multiple imputation for handling missing data prior to estimating adjusted relative risks from a correctly specified multivariable log binomial model. We considered an arbitrary pattern of missing data in both outcome and exposure variables, with missing data induced under missing at random mechanisms. Focusing on standard model-based methods of multiple imputation, missing data were imputed using multivariate normal imputation or fully conditional specification with a logistic imputation model for the outcome. Multivariate normal imputation performed poorly in the simulation study, consistently producing estimates of the relative risk that were biased towards the null. Despite outperforming multivariate normal imputation, fully conditional specification also produced somewhat biased estimates, with greater bias observed for higher outcome prevalences and larger relative risks. Deleting imputed outcomes from analysis datasets did not improve the performance of fully conditional specification. Both multivariate normal imputation and fully conditional specification produced biased estimates of the relative risk, presumably since both use a misspecified imputation model. Based on simulation results, we recommend researchers use fully conditional specification rather than multivariate normal imputation and retain imputed outcomes in the analysis when estimating relative risks. However fully conditional specification is not without its shortcomings, and so further research is needed to identify optimal approaches for relative risk estimation within the multiple imputation framework.

  3. Choosing relatives for DNA identification of missing persons.

    PubMed

    Ge, Jianye; Budowle, Bruce; Chakraborty, Ranajit

    2011-01-01

    DNA-based analysis is integral to missing person identification cases. When direct references are not available, indirect relative references can be used to identify missing persons by kinship analysis. Generally, more reference relatives render greater accuracy of identification. However, it is costly to type multiple references. Thus, at times, decisions may need to be made on which relatives to type. In this study, pedigrees for 37 common reference scenarios with 13 CODIS STRs were simulated to rank the information content of different combinations of relatives. The results confirm that first-order relatives (parents and fullsibs) are the most preferred relatives to identify missing persons; fullsibs are also informative. Less genetic dependence between references provides a higher on average likelihood ratio. Distant relatives may not be helpful solely by autosomal markers. But lineage-based Y chromosome and mitochondrial DNA markers can increase the likelihood ratio or serve as filters to exclude putative relationships. © 2010 American Academy of Forensic Sciences.

  4. Minimax Rate-optimal Estimation of High-dimensional Covariance Matrices with Incomplete Data*

    PubMed Central

    Cai, T. Tony; Zhang, Anru

    2016-01-01

    Missing data occur frequently in a wide range of applications. In this paper, we consider estimation of high-dimensional covariance matrices in the presence of missing observations under a general missing completely at random model in the sense that the missingness is not dependent on the values of the data. Based on incomplete data, estimators for bandable and sparse covariance matrices are proposed and their theoretical and numerical properties are investigated. Minimax rates of convergence are established under the spectral norm loss and the proposed estimators are shown to be rate-optimal under mild regularity conditions. Simulation studies demonstrate that the estimators perform well numerically. The methods are also illustrated through an application to data from four ovarian cancer studies. The key technical tools developed in this paper are of independent interest and potentially useful for a range of related problems in high-dimensional statistical inference with missing data. PMID:27777471

  5. Minimax Rate-optimal Estimation of High-dimensional Covariance Matrices with Incomplete Data.

    PubMed

    Cai, T Tony; Zhang, Anru

    2016-09-01

    Missing data occur frequently in a wide range of applications. In this paper, we consider estimation of high-dimensional covariance matrices in the presence of missing observations under a general missing completely at random model in the sense that the missingness is not dependent on the values of the data. Based on incomplete data, estimators for bandable and sparse covariance matrices are proposed and their theoretical and numerical properties are investigated. Minimax rates of convergence are established under the spectral norm loss and the proposed estimators are shown to be rate-optimal under mild regularity conditions. Simulation studies demonstrate that the estimators perform well numerically. The methods are also illustrated through an application to data from four ovarian cancer studies. The key technical tools developed in this paper are of independent interest and potentially useful for a range of related problems in high-dimensional statistical inference with missing data.

  6. Pattern masking: the importance of remote spatial frequencies and their phase alignment.

    PubMed

    Huang, Pi-Chun; Maehara, Goro; May, Keith A; Hess, Robert F

    2012-02-16

    To assess the effects of spatial frequency and phase alignment of mask components in pattern masking, target threshold vs. mask contrast (TvC) functions for a sine-wave grating (S) target were measured for five types of mask: a sine-wave grating (S), a square-wave grating (Q), a missing fundamental square-wave grating (M), harmonic complexes consisting of phase-scrambled harmonics of a square wave (Qp), and harmonic complexes consisting of phase-scrambled harmonics of a missing fundamental square wave (Mp). Target and masks had the same fundamental frequency (0.46 cpd) and the target was added in phase with the fundamental frequency component of the mask. Under monocular viewing conditions, the strength of masking depends on phase relationships among mask spatial frequencies far removed from that of the target, at least 3 times the target frequency, only when there are common target and mask spatial frequencies. Under dichoptic viewing conditions, S and Q masks produced similar masking to each other and the phase-scrambled masks (Qp and Mp) produced less masking. The results suggest that pattern masking is spatial frequency broadband in nature and sensitive to the phase alignments of spatial components.

  7. A method to estimate the additional uncertainty in gap-filled NEE resulting from long gaps in the CO2 flux record

    Treesearch

    Andrew D. Richardson; David Y. Hollinger

    2007-01-01

    Missing values in any data set create problems for researchers. The process by which missing values are replaced, and the data set is made complete, is generally referred to as imputation. Within the eddy flux community, the term "gap filling" is more commonly applied. A major challenge is that random errors in measured data result in uncertainty in the gap-...

  8. UV imaging reveals facial areas that are prone to skin cancer are disproportionately missed during sunscreen application.

    PubMed

    Pratt, Harry; Hassanin, Kareem; Troughton, Lee D; Czanner, Gabriela; Zheng, Yalin; McCormick, Austin G; Hamill, Kevin J

    2017-01-01

    Application of sunscreen is a widely used mechanism for protecting skin from the harmful effects of UV light. However, protection can only be achieved through effective application, and areas that are routinely missed are likely at increased risk of UV damage. Here we sought to determine if specific areas of the face are missed during routine sunscreen application, and whether provision of public health information is sufficient to improve coverage. To investigate this, 57 participants were imaged with a UV sensitive camera before and after sunscreen application: first visit; minimal pre-instruction, second visit; provided with a public health information statement. Images were scored using a custom automated image analysis process designed to identify areas of high UV reflectance, i.e. missed during sunscreen application, and analysed for 5% significance. Analyses revealed eyelid and periorbital regions to be disproportionately missed during routine sunscreen application (median 14% missed in eyelid region vs 7% in rest of face, p<0.01). Provision of health information caused a significant improvement in coverage to eyelid areas in general however, the medial canthal area was still frequently missed. These data reveal that a public health announcement-type intervention could be effective at improving coverage of high risk areas of the face, however high risk areas are likely to remain unprotected therefore other mechanisms of sun protection should be widely promoted such as UV blocking sunglasses.

  9. Comparative anatomy of the pelvic vessels in the bearded capuchin (Sapajus libidinosus) and baboons, apes and modern humans.

    PubMed

    Aversi-Ferreira, Roqueline A G M F; de Souza Vieira, Vanessa; Tomaz, Carlos; Aversi-Ferreira, Tales Alexandre

    2014-01-01

    Cebus/Sapajus has shown high cognitive and manipulatory behaviour as well as intermittent bipedalism. Although the function of the muscles and bones of this genus has been widely investigated, the arterial system that supports these tissues has not been studied in much detail, and a full description of the blood vessels of the pelvis is still missing. Therefore, we studied the vessels of the pelvis of Sapajus libidinosus in terms of their origin, distribution and muscle irrigation and compared them with those of other primates available in the literature. In general, the distribution pattern and origin of arteries in the pelvis of the bearded capuchin are more similar to those of baboons compared to other primates. This similarity may be because both have a tail, a similar body shape and use, preferentially, quadrupedal movement. 2014 S. Karger AG, Basel

  10. Discovery of multi-ring basins - Gestalt perception in planetary science

    NASA Technical Reports Server (NTRS)

    Hartmann, W. K.

    1981-01-01

    Early selenographers resolved individual structural components of multi-ring basin systems but missed the underlying large-scale multi-ring basin patterns. The recognition of multi-ring basins as a general class of planetary features can be divided into five steps. Gilbert (1893) took a first step in recognizing radial 'sculpture' around the Imbrium basin system. Several writers through the 1940's rediscovered the radial sculpture and extended this concept by describing concentric rings around several circular maria. Some reminiscences are given about the fourth step - discovery of the Orientale basin and other basin systems by rectified lunar photography at the University of Arizona in 1961-62. Multi-ring basins remained a lunar phenomenon until the fifth step - discovery of similar systems of features on other planets, such as Mars (1972), Mercury (1974), and possibly Callisto and Ganymede (1979). This sequence is an example of gestalt recognition whose implications for scientific research are discussed.

  11. Development of a non-invasive, multifunctional grasp neuroprosthesis and its evaluation in an individual with a high spinal cord injury.

    PubMed

    Rupp, Rüdiger; Kreilinger, Alex; Rohm, Martin; Kaiser, Vera; Müller-Putz, Gernot R

    2012-01-01

    Over the last decade the improvement of a missing hand function by application of neuroprostheses in particular the implantable Freehand system has been successfully shown in high spinal cord injured individuals. The clinically proven advantages of the Freehand system is its ease of use, the reproducible generation of two distinct functional grasp patterns and an analog control scheme based on movements of the contralateral shoulder. However, after the Freehand system is not commercially available for more than ten years, alternative grasp neuroprosthesis with a comparable functionality are still missing. Therefore, the aim of this study was to develop a non-invasive neuroprosthesis and to show that a degree of functional restoration can be provided to end users comparable to implanted devices. By introduction of an easy to handle forearm electrode sleeve the reproducible generation of two grasp patterns has been achieved. Generated grasp forces of the palmar grasp are in the range of the implanted system. Though pinch force of the lateral grasp is significantly lower, it can effectively used by a tetraplegic subject to perform functional tasks. The non-invasive grasp neuroprosthesis developed in this work may serve as an easy to apply and inexpensive way to restore a missing hand and finger function at any time after spinal cord injury.

  12. A systematic review of randomised controlled trials in rheumatoid arthritis: the reporting and handling of missing data in composite outcomes.

    PubMed

    Ibrahim, Fowzia; Tom, Brian D M; Scott, David L; Prevost, Andrew Toby

    2016-06-02

    Most reported outcome measures in rheumatoid arthritis (RA) trials are composite, whose components comprise single measures that are combined into one outcome. The aims of this review were to assess the range of missing data rates in primary composite outcomes and to document the current practice for handling and reporting missing data in published RA trials compared to the Consolidated Standards of Reporting Trials (CONSORT) recommendations. A systematic search for randomised controlled trials was conducted for RA trials published between 2008 and 2013 in four rheumatology and four high impact general medical journals. A total of 51 trials with a composite primary outcome were identified, of which 38 (75 %) used the binary American College of Rheumatology responder index and 13 (25 %) used the Disease Activity Score for 28 joints (DAS28). Forty-four trials (86 %) reported on an intention-to-treat analysis population, while 7 trials (14 %) analysed according to a modified intention-to-treat population. Missing data rates for the primary composite outcome ranged from 2-53 % and were above 30 % in 9 trials, 20-30 % in 11 trials, 10-20 % in 18 trials and below 10 % in 13 trials. Thirty-eight trials (75 %) used non-responder imputation and 10 (20 %) used last observation carried forward to impute missing composite outcome data at the primary time point. The rate of dropout was on average 61 % times higher in the placebo group compared to the treatment group in the 34 placebo controlled trials (relative rate 1.61, 95 % CI: 1.29, 2.02). Thirty-seven trials (73 %) did not report the use of sensitivity analyses to assess the handling of missing data in the primary analysis as recommended by CONSORT guidelines. This review highlights an improvement in rheumatology trial practice since the revision of CONSORT guidelines, in terms of power calculation and participant's flow diagram. However, there is a need to improve the handling and reporting of missing composite outcome data and their components in RA trials. In particular, sensitivity analyses need to be more widely used in RA trials because imputation is widespread and generally uses single imputation methods, and in this area the missing data rates are commonly differentially higher in the placebo group.

  13. Nearest neighbor imputation using spatial–temporal correlations in wireless sensor networks

    PubMed Central

    Li, YuanYuan; Parker, Lynne E.

    2016-01-01

    Missing data is common in Wireless Sensor Networks (WSNs), especially with multi-hop communications. There are many reasons for this phenomenon, such as unstable wireless communications, synchronization issues, and unreliable sensors. Unfortunately, missing data creates a number of problems for WSNs. First, since most sensor nodes in the network are battery-powered, it is too expensive to have the nodes retransmit missing data across the network. Data re-transmission may also cause time delays when detecting abnormal changes in an environment. Furthermore, localized reasoning techniques on sensor nodes (such as machine learning algorithms to classify states of the environment) are generally not robust enough to handle missing data. Since sensor data collected by a WSN is generally correlated in time and space, we illustrate how replacing missing sensor values with spatially and temporally correlated sensor values can significantly improve the network’s performance. However, our studies show that it is important to determine which nodes are spatially and temporally correlated with each other. Simple techniques based on Euclidean distance are not sufficient for complex environmental deployments. Thus, we have developed a novel Nearest Neighbor (NN) imputation method that estimates missing data in WSNs by learning spatial and temporal correlations between sensor nodes. To improve the search time, we utilize a kd-tree data structure, which is a non-parametric, data-driven binary search tree. Instead of using traditional mean and variance of each dimension for kd-tree construction, and Euclidean distance for kd-tree search, we use weighted variances and weighted Euclidean distances based on measured percentages of missing data. We have evaluated this approach through experiments on sensor data from a volcano dataset collected by a network of Crossbow motes, as well as experiments using sensor data from a highway traffic monitoring application. Our experimental results show that our proposed 𝒦-NN imputation method has a competitive accuracy with state-of-the-art Expectation–Maximization (EM) techniques, while using much simpler computational techniques, thus making it suitable for use in resource-constrained WSNs. PMID:28435414

  14. Content Analysis of Contemporary Teen Magazines for Adolescent Females.

    ERIC Educational Resources Information Center

    Evans, Ellis D.; And Others

    1991-01-01

    Patterns in the content of three commercial magazines ("Sassy,""Seventeen," and "Young Miss") oriented toward adolescent female consumers were analyzed by three trained raters. Findings are discussed in terms of print media utilization by adolescents; themes of self-improvement, identity development, and achievement;…

  15. Discovering Structural Regularity in 3D Geometry

    PubMed Central

    Pauly, Mark; Mitra, Niloy J.; Wallner, Johannes; Pottmann, Helmut; Guibas, Leonidas J.

    2010-01-01

    We introduce a computational framework for discovering regular or repeated geometric structures in 3D shapes. We describe and classify possible regular structures and present an effective algorithm for detecting such repeated geometric patterns in point- or mesh-based models. Our method assumes no prior knowledge of the geometry or spatial location of the individual elements that define the pattern. Structure discovery is made possible by a careful analysis of pairwise similarity transformations that reveals prominent lattice structures in a suitable model of transformation space. We introduce an optimization method for detecting such uniform grids specifically designed to deal with outliers and missing elements. This yields a robust algorithm that successfully discovers complex regular structures amidst clutter, noise, and missing geometry. The accuracy of the extracted generating transformations is further improved using a novel simultaneous registration method in the spatial domain. We demonstrate the effectiveness of our algorithm on a variety of examples and show applications to compression, model repair, and geometry synthesis. PMID:21170292

  16. Unusual scarring patterns on cardiac magnetic resonance imaging: A potentially treatable etiology not to be missed.

    PubMed

    Jordan, Andrew; Lyne, Jonathan; Wong, Tom

    2010-04-01

    A case of cardiomyopathy and ventricular tachycardia previously assumed to be idiopathic in origin is described. Investigation with cardiac magnetic resonance imaging prompted the diagnosis and successful treatment of an underlying disorder based on typical scarring patterns seen with late gadolinium enhancement. The present report suggests that clinicians should have a low threshold for actively excluding this condition in patients presenting with cardiomyopathy, even in the absence of other disease features, particularly if typical scarring patterns are found on cardiac magnetic resonance imaging because disease-specific therapy appears to significantly improve both symptoms and prognosis.

  17. How to improve breeding value prediction for feed conversion ratio in the case of incomplete longitudinal body weights.

    PubMed

    Tran, V H Huynh; Gilbert, H; David, I

    2017-01-01

    With the development of automatic self-feeders, repeated measurements of feed intake are becoming easier in an increasing number of species. However, the corresponding BW are not always recorded, and these missing values complicate the longitudinal analysis of the feed conversion ratio (FCR). Our aim was to evaluate the impact of missing BW data on estimations of the genetic parameters of FCR and ways to improve the estimations. On the basis of the missing BW profile in French Large White pigs (male pigs weighed weekly, females and castrated males weighed monthly), we compared 2 different ways of predicting missing BW, 1 using a Gompertz model and 1 using a linear interpolation. For the first part of the study, we used 17,398 weekly records of BW and feed intake recorded over 16 consecutive weeks in 1,222 growing male pigs. We performed a simulation study on this data set to mimic missing BW values according to the pattern of weekly proportions of incomplete BW data in females and castrated males. The FCR was then computed for each week using observed data (obser_FCR), data with missing BW (miss_FCR), data with BW predicted using a Gompertz model (Gomp_FCR), and data with BW predicted by linear interpolation (interp_FCR). Heritability (h) was estimated, and the EBV was predicted for each repeated FCR using a random regression model. In the second part of the study, the full data set (males with their complete BW records, castrated males and females with missing BW) was analyzed using the same methods (miss_FCR, Gomp_FCR, and interp_FCR). Results of the simulation study showed that h were overestimated in the case of missing BW and that predicting BW using a linear interpolation provided a more accurate estimation of h and of EBV than a Gompertz model. Over 100 simulations, the correlation between obser_EBV and interp_EBV, Gomp_EBV, and miss_EBV was 0.93 ± 0.02, 0.91 ± 0.01, and 0.79 ± 0.04, respectively. The heritabilities obtained with the full data set were quite similar for miss_FCR, Gomp_FCR, and interp_FCR. In conclusion, when the proportion of missing BW is high, genetic parameters of FCR are not well estimated. In French Large White pigs, in the growing period extending from d 65 to 168, prediction of missing BW using a Gompertz growth model slightly improved the estimations, but the linear interpolation improved the estimation to a greater extent. This result is due to the linear rather than sigmoidal increase in BW over the study period.

  18. Revamping Newtonian Gravity

    NASA Astrophysics Data System (ADS)

    Eckhardt, Donald H.; Garrido Pestaña, José Luis

    2014-06-01

    The nineteenth century's quest for the missing matter (Vulcan) ended with the publication of Einstein's General Theory of Relativity. We contend that the current quest for the missing matter is parallel in its perseverance and in its ultimate futility. After setting the search for dark matter in its historic perspective, we critique extant dark matter models and offer alternative explanations -- derived from a Lorentz-invariant Lagrangian -- that will, at the very least, sow seeds of doubt about the existence of dark matter.

  19. Causal inference with missing exposure information: Methods and applications to an obstetric study.

    PubMed

    Zhang, Zhiwei; Liu, Wei; Zhang, Bo; Tang, Li; Zhang, Jun

    2016-10-01

    Causal inference in observational studies is frequently challenged by the occurrence of missing data, in addition to confounding. Motivated by the Consortium on Safe Labor, a large observational study of obstetric labor practice and birth outcomes, this article focuses on the problem of missing exposure information in a causal analysis of observational data. This problem can be approached from different angles (i.e. missing covariates and causal inference), and useful methods can be obtained by drawing upon the available techniques and insights in both areas. In this article, we describe and compare a collection of methods based on different modeling assumptions, under standard assumptions for missing data (i.e. missing-at-random and positivity) and for causal inference with complete data (i.e. no unmeasured confounding and another positivity assumption). These methods involve three models: one for treatment assignment, one for the dependence of outcome on treatment and covariates, and one for the missing data mechanism. In general, consistent estimation of causal quantities requires correct specification of at least two of the three models, although there may be some flexibility as to which two models need to be correct. Such flexibility is afforded by doubly robust estimators adapted from the missing covariates literature and the literature on causal inference with complete data, and by a newly developed triply robust estimator that is consistent if any two of the three models are correct. The methods are applied to the Consortium on Safe Labor data and compared in a simulation study mimicking the Consortium on Safe Labor. © The Author(s) 2013.

  20. Generalizing MOND to explain the missing mass in galaxy clusters

    NASA Astrophysics Data System (ADS)

    Hodson, Alistair O.; Zhao, Hongsheng

    2017-02-01

    Context. MOdified Newtonian Dynamics (MOND) is a gravitational framework designed to explain the astronomical observations in the Universe without the inclusion of particle dark matter. MOND, in its current form, cannot explain the missing mass in galaxy clusters without the inclusion of some extra mass, be it in the form of neutrinos or non-luminous baryonic matter. We investigate whether the MOND framework can be generalized to account for the missing mass in galaxy clusters by boosting gravity in high gravitational potential regions. We examine and review Extended MOND (EMOND), which was designed to increase the MOND scale acceleration in high potential regions, thereby boosting the gravity in clusters. Aims: We seek to investigate galaxy cluster mass profiles in the context of MOND with the primary aim at explaining the missing mass problem fully without the need for dark matter. Methods: Using the assumption that the clusters are in hydrostatic equilibrium, we can compute the dynamical mass of each cluster and compare the result to the predicted mass of the EMOND formalism. Results: We find that EMOND has some success in fitting some clusters, but overall has issues when trying to explain the mass deficit fully. We also investigate an empirical relation to solve the cluster problem, which is found by analysing the cluster data and is based on the MOND paradigm. We discuss the limitations in the text.

  1. The Estimation of Gestational Age at Birth in Database Studies.

    PubMed

    Eberg, Maria; Platt, Robert W; Filion, Kristian B

    2017-11-01

    Studies on the safety of prenatal medication use require valid estimation of the pregnancy duration. However, gestational age is often incompletely recorded in administrative and clinical databases. Our objective was to compare different approaches to estimating the pregnancy duration. Using data from the Clinical Practice Research Datalink and Hospital Episode Statistics, we examined the following four approaches to estimating missing gestational age: (1) generalized estimating equations for longitudinal data; (2) multiple imputation; (3) estimation based on fetal birth weight and sex; and (4) conventional approaches that assigned a fixed value (39 weeks for all or 39 weeks for full term and 35 weeks for preterm). The gestational age recorded in Hospital Episode Statistics was considered the gold standard. We conducted a simulation study comparing the described approaches in terms of estimated bias and mean square error. A total of 25,929 infants from 22,774 mothers were included in our "gold standard" cohort. The smallest average absolute bias was observed for the generalized estimating equation that included birth weight, while the largest absolute bias occurred when assigning 39-week gestation to all those with missing values. The smallest mean square errors were detected with generalized estimating equations while multiple imputation had the highest mean square errors. The use of generalized estimating equations resulted in the most accurate estimation of missing gestational age when birth weight information was available. In the absence of birth weight, assignment of fixed gestational age based on term/preterm status may be the optimal approach.

  2. A novel method about detecting missing holes on the motor carling

    NASA Astrophysics Data System (ADS)

    Xu, Hongsheng; Tan, Hao; Li, Guirong

    2018-03-01

    After a deep analysis on how to use an image processing system to detect the missing holes on the motor carling, we design the whole system combined with the actual production conditions of the motor carling. Afterwards we explain the whole system's hardware and software in detail. We introduce the general functions for the system's hardware and software. Analyzed these general functions, we discuss the modules of the system's hardware and software and the theory to design these modules in detail. The measurement to confirm the area to image processing, edge detection, randomized Hough transform to circle detecting is explained in detail. Finally, the system result tested in the laboratory and in the factory is given out.

  3. UV imaging reveals facial areas that are prone to skin cancer are disproportionately missed during sunscreen application

    PubMed Central

    Troughton, Lee D.; Czanner, Gabriela; Zheng, Yalin; McCormick, Austin G.

    2017-01-01

    Application of sunscreen is a widely used mechanism for protecting skin from the harmful effects of UV light. However, protection can only be achieved through effective application, and areas that are routinely missed are likely at increased risk of UV damage. Here we sought to determine if specific areas of the face are missed during routine sunscreen application, and whether provision of public health information is sufficient to improve coverage. To investigate this, 57 participants were imaged with a UV sensitive camera before and after sunscreen application: first visit; minimal pre-instruction, second visit; provided with a public health information statement. Images were scored using a custom automated image analysis process designed to identify areas of high UV reflectance, i.e. missed during sunscreen application, and analysed for 5% significance. Analyses revealed eyelid and periorbital regions to be disproportionately missed during routine sunscreen application (median 14% missed in eyelid region vs 7% in rest of face, p<0.01). Provision of health information caused a significant improvement in coverage to eyelid areas in general however, the medial canthal area was still frequently missed. These data reveal that a public health announcement-type intervention could be effective at improving coverage of high risk areas of the face, however high risk areas are likely to remain unprotected therefore other mechanisms of sun protection should be widely promoted such as UV blocking sunglasses. PMID:28968413

  4. Missed Work Due to Occupational Illness among Hispanic Horse Workers.

    PubMed

    Bush, Ashley M; Westneat, Susan; Browning, Steven R; Swanberg, Jennifer

    2018-05-07

    Occupational illnesses are inadequately reported for agriculture, an industry dominated by a vulnerable Hispanic population and high fatal and nonfatal injury rates. Work-related illnesses can contribute to missed work, caused by a combination of personal and work factors, with costs to the individual, employer, and society. To better understand agricultural occupational illnesses, 225 Hispanic horse workers were interviewed via community-based convenience sampling. Descriptive statistics, bivariate analyses, and log binomial regression modeling were used to: (1) describe the prevalence of missed work due to work-related illnesses among Hispanic horse workers, (2) examine work-related and personal factors associated with missed work, and (3) identify health symptoms and work-related characteristics potentially associated with missed work. Key findings reveal that having at least one child (PR = 1.71, 95% CI = 1.03, 2.84), having poor self-reported general health (PR = 0.72, 95% CI = 0.48, 1.08), experiencing stress during a typical workday (PR = 2.58, 95% CI = 1.25, 5.32), or spending less time with horses (PR = 1.87, 95% CI = 1.15, 3.05) are significant predictors of missing work. Interventions can be designed to identify workers most susceptible to missing work and provide resources to reduce absenteeism. Future research should examine work-related illness in agricultural horse production, including personal and work-related factors, in order to diminish occupational health disparities among these workers, who are more likely to be employed in hazardous agricultural work. Copyright© by the American Society of Agricultural Engineers.

  5. Weber’s Law, the Magnitude Effect and Discrimination of Sugar Concentrations in Nectar-Feeding Animals

    PubMed Central

    Nachev, Vladislav; Stich, Kai Petra; Winter, York

    2013-01-01

    Weber’s law quantifies the perception of difference between stimuli. For instance, it can explain why we are less likely to detect the removal of three nuts from a bowl if the bowl is full than if it is nearly empty. This is an example of the magnitude effect – the phenomenon that the subjective perception of a linear difference between a pair of stimuli progressively diminishes when the average magnitude of the stimuli increases. Although discrimination performances of both human and animal subjects in various sensory modalities exhibit the magnitude effect, results sometimes systematically deviate from the quantitative predictions based on Weber’s law. An attempt to reformulate the law to better fit data from acoustic discrimination tasks has been dubbed the “near-miss to Weber’s law”. Here, we tested the gustatory discrimination performance of nectar-feeding bats (Glossophaga soricina), in order to investigate whether the original version of Weber’s law accurately predicts choice behavior in a two-alternative forced choice task. As expected, bats either preferred the sweeter of the two options or showed no preference. In 4 out of 6 bats the near-miss to Weber’s law provided a better fit and Weber’s law underestimated the magnitude effect. In order to test the generality of this observation in nectar-feeders, we reviewed previously published data on bats, hummingbirds, honeybees, and bumblebees. In all groups of animals the near-miss to Weber’s law provided better fits than Weber’s law. Furthermore, whereas the magnitude effect was stronger than predicted by Weber’s law in vertebrates, it was weaker than predicted in insects. Thus nectar-feeding vertebrates and insects seem to differ in how their choice behavior changes as sugar concentration is increased. We discuss the ecological and evolutionary implications of the observed patterns of sugar concentration discrimination. PMID:24040189

  6. Interlanguage Variation: A Point Missed?

    ERIC Educational Resources Information Center

    Tice, Bradley Scott

    A study investigated patterns in phonological errors occurring in the speaker's second language in both formal and informal speaking situations. Subjects were three adult learners of English as a second language, including a native Spanish-speaker and two Asians. Their speech was recorded during diagnostic testing (formal speech) and in everyday…

  7. Morphological Spatial Pattern Analysis of the Conterminous US

    EPA Science Inventory

    Six data layers, all created using GUIDOS 1.3 MSPA software to identify green infrastructure components (e.g. core, edge, corridor, etc.). Water was treated three different ways: 1) as foreground, 2) as background, and 3) as missing using both NLCD 2001 and 2006 for six total lay...

  8. Genetics Home Reference: Léri-Weill dyschondrosteosis

    MedlinePlus

    ... both females (who have two X chromosomes) and males (who have one X and one Y chromosome ) normally have two functional copies of the SHOX gene in each cell. The inheritance pattern of Léri-Weill dyschondrosteosis is described as dominant because one missing or altered copy of the ...

  9. The mean-square error optimal linear discriminant function and its application to incomplete data vectors

    NASA Technical Reports Server (NTRS)

    Walker, H. F.

    1979-01-01

    In many pattern recognition problems, data vectors are classified although one or more of the data vector elements are missing. This problem occurs in remote sensing when the ground is obscured by clouds. Optimal linear discrimination procedures for classifying imcomplete data vectors are discussed.

  10. Spatial perspectives in state-and-transition models: A missing link to land management?

    USDA-ARS?s Scientific Manuscript database

    Conceptual models of alternative states and thresholds are based largely on observations of ecosystem processes at a few points in space. Because the distribution of alternative states in spatially-structured ecosystems is the result of variations in pattern-process interactions at different scales,...

  11. Missing data frequency and correlates in two randomized surgical trials for urinary incontinence in women.

    PubMed

    Brubaker, Linda; Litman, Heather J; Kim, Hae-Young; Zimmern, Philippe; Dyer, Keisha; Kusek, John W; Richter, Holly E; Stoddard, Anne

    2015-08-01

    Missing data is frequently observed in clinical trials; high rates of missing data may jeopardize trial outcome validity. We determined the rates of missing data over time, by type of data collected and compared demographic and clinical factors associated with missing data among women who participated in two large randomized clinical trials of surgery for stress urinary incontinence, the Stress Incontinence Surgical Treatment Efficacy Trial (SISTEr) and the Trial of Midurethral Sling (TOMUS). The proportions of subjects who attended and missed each follow-up visit were calculated. The chi-squared test, Fisher's exact test and t test were used to compare women with and without missing data, as well as the completeness of the data for each component of the composite primary outcome. Data completeness for the primary outcome computation in the TOMUS trial (62.3%) was nearly double that in the SISTEr trial (35.7%). The follow-up visit attendance rate decreased over time. A higher proportion of subjects attended all follow-up visits in the TOMUS trial and overall there were fewer missing data for the period that included the primary outcome assessment at 12 months. The highest levels of complete data for the composite outcome variables were for the symptoms questionnaire (SISTEr 100 %, TOMUS 99.8%) and the urinary stress test (SISTEr 96.1%, TOMUS 96.7%). In both studies, the pad test was associated with the lowest levels of complete data (SISTEr 85.1%, TOMUS 88.3%) and approximately one in ten subjects had incomplete voiding diaries at the time of primary outcome assessment. Generally, in both studies, a higher proportion of younger subjects had missing data. This analysis lacked a patient perspective as to the reasons for missing data that could have provided additional information on subject burden, motivations for adherence and study design. In addition, we were unable to compare the effects of the different primary outcome assessment time-points in an identically designed trial. Missing visits and data increased with time. Questionnaire data and physical outcome data (urinary stress test) that could be assessed during a visit were least prone to missing data, whereas data for variables that required subject effort while away from the research team (pad test, voiding diary) were more likely to be missing. Older subjects were more likely to provide complete data.

  12. 32 CFR 718.1 - General provisions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 5 2012-07-01 2012-07-01 false General provisions. 718.1 Section 718.1 National Defense Department of Defense (Continued) DEPARTMENT OF THE NAVY PERSONNEL MISSING PERSONS ACT § 718.1... information is received in the Department. The determination of the Secretary of the Navy, or of such...

  13. More than One Way: Stories of UDL and Inclusive Classrooms

    ERIC Educational Resources Information Center

    Lowrey, K. Alisa; Hollingshead, Aleksandra; Howery, Kathy; Bishop, John B.

    2017-01-01

    Voices of practitioners are often missing in research studies. This project focused on examining general education teachers' stories as they relate to implementation of Universal Design for Learning (UDL) framework and inclusion of students with moderate to severe intellectual disability. Seven general education teachers from Canada and the United…

  14. Morphological Idiosyncracies in Classical Arabic: Evidence Favoring Lexical Representations over Rules.

    ERIC Educational Resources Information Center

    Miller, Ann M.

    A lexical representational analysis of Classical Arabic is proposed that captures a generalization that McCarthy's (1979, 1981) autosegmental analysis misses, namely that idiosyncratic characteristics of the derivational binyanim in Arabic are lexical, not morphological. This analysis captures that generalization by treating all the idiosyncracies…

  15. Posttraumatic Growth Among Family Members With Missing Persons From War in Kosovo: Association With Social Support and Community Involvement.

    PubMed

    Arenliu, Aliriza; Shala-Kastrati, Fatmire; Berisha Avdiu, Vjollca; Landsman, Moshe

    2017-01-01

    There is almost no data on the role of social support and in general on posttraumatic growth among people who have missing family member(s) as result of war and who experience ambiguous loss. This study explores relationship between reported posttraumatic growth and perceived social support and social activism in community-based organizations dealing directly with issues of missing persons. Family members who reported higher levels of social support from family, friends, and important others reported significant higher levels of posttraumatic growth. Family members that reported being active in community-based organizations reported significant higher averages in posttraumatic growth scores in total and its subscales. Regression analyses indicates that factors associated posttraumatic growth were as follows: being active in community organization dealing with missing person's issues and higher levels of social support from friends and family. Findings provide insight for clinicians working with this population and psycho social experts working in postconflict contexts.

  16. Multivariate longitudinal data analysis with censored and intermittent missing responses.

    PubMed

    Lin, Tsung-I; Lachos, Victor H; Wang, Wan-Lun

    2018-05-08

    The multivariate linear mixed model (MLMM) has emerged as an important analytical tool for longitudinal data with multiple outcomes. However, the analysis of multivariate longitudinal data could be complicated by the presence of censored measurements because of a detection limit of the assay in combination with unavoidable missing values arising when subjects miss some of their scheduled visits intermittently. This paper presents a generalization of the MLMM approach, called the MLMM-CM, for a joint analysis of the multivariate longitudinal data with censored and intermittent missing responses. A computationally feasible expectation maximization-based procedure is developed to carry out maximum likelihood estimation within the MLMM-CM framework. Moreover, the asymptotic standard errors of fixed effects are explicitly obtained via the information-based method. We illustrate our methodology by using simulated data and a case study from an AIDS clinical trial. Experimental results reveal that the proposed method is able to provide more satisfactory performance as compared with the traditional MLMM approach. Copyright © 2018 John Wiley & Sons, Ltd.

  17. Investigating Factorial Invariance of Latent Variables Across Populations When Manifest Variables Are Missing Completely

    PubMed Central

    Widaman, Keith F.; Grimm, Kevin J.; Early, Dawnté R.; Robins, Richard W.; Conger, Rand D.

    2013-01-01

    Difficulties arise in multiple-group evaluations of factorial invariance if particular manifest variables are missing completely in certain groups. Ad hoc analytic alternatives can be used in such situations (e.g., deleting manifest variables), but some common approaches, such as multiple imputation, are not viable. At least 3 solutions to this problem are viable: analyzing differing sets of variables across groups, using pattern mixture approaches, and a new method using random number generation. The latter solution, proposed in this article, is to generate pseudo-random normal deviates for all observations for manifest variables that are missing completely in a given sample and then to specify multiple-group models in a way that respects the random nature of these values. An empirical example is presented in detail comparing the 3 approaches. The proposed solution can enable quantitative comparisons at the latent variable level between groups using programs that require the same number of manifest variables in each group. PMID:24019738

  18. A Temporal Mining Framework for Classifying Un-Evenly Spaced Clinical Data: An Approach for Building Effective Clinical Decision-Making System.

    PubMed

    Jane, Nancy Yesudhas; Nehemiah, Khanna Harichandran; Arputharaj, Kannan

    2016-01-01

    Clinical time-series data acquired from electronic health records (EHR) are liable to temporal complexities such as irregular observations, missing values and time constrained attributes that make the knowledge discovery process challenging. This paper presents a temporal rough set induced neuro-fuzzy (TRiNF) mining framework that handles these complexities and builds an effective clinical decision-making system. TRiNF provides two functionalities namely temporal data acquisition (TDA) and temporal classification. In TDA, a time-series forecasting model is constructed by adopting an improved double exponential smoothing method. The forecasting model is used in missing value imputation and temporal pattern extraction. The relevant attributes are selected using a temporal pattern based rough set approach. In temporal classification, a classification model is built with the selected attributes using a temporal pattern induced neuro-fuzzy classifier. For experimentation, this work uses two clinical time series dataset of hepatitis and thrombosis patients. The experimental result shows that with the proposed TRiNF framework, there is a significant reduction in the error rate, thereby obtaining the classification accuracy on an average of 92.59% for hepatitis and 91.69% for thrombosis dataset. The obtained classification results prove the efficiency of the proposed framework in terms of its improved classification accuracy.

  19. Children's missed healthcare appointments: professional and organisational responses.

    PubMed

    Appleton, Jane; Powell, Catherine; Coombes, Lindsey

    2016-09-01

    This National Society for the Prevention of Cruelty to Children (NSPCC) funded UK study sought to examine organisational and professional responses to children's missed healthcare appointments. The study comprised two parts: phase I was a web-based scoping and systematic analysis of UK National Health Service healthcare organisations' internal policies on missed appointments. Phase II involved a case study of how missed appointments were managed within one hospital trust, including interviews with hospital-based staff, review of organisational data and examination of policies and 'systems' in place. Policies accessed were of variable quality when benchmarked against a predetermined set of evidence-based standards. Additional material (eg, board minutes) gleaned through the searches found an apparent disconnect between nationally determined safeguarding requirements and strategies to reduce the cost pressures arising from missed appointments. Findings from the case study included the continuing use of the adult-centric term 'did not attend' (DNA), the challenges that may be inherent in attending appointments (with concomitant sympathy for parents) and a need to further explore general practitioner responses to DNA notifications, particularly given the acknowledged association between missed appointments and child maltreatment. The web-based scoping exercise yielded a small number of organisational policies. These were of variable quality when rated against predetermined standards. Other material gathered through the search strategy found evidence that 'missed appointment' strategies aimed at reducing costs did not always acknowledge the discrete needs of children. The case study findings contribute to an understanding of the complexities and challenges of responding to a missed appointment and the importance of taking a child-centred approach. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  20. The differential effects of acute right- vs. left-sided vestibular failure on brain metabolism.

    PubMed

    Becker-Bense, Sandra; Dieterich, Marianne; Buchholz, Hans-Georg; Bartenstein, Peter; Schreckenberger, Mathias; Brandt, Thomas

    2014-07-01

    The human vestibular system is represented in the brain bilaterally, but it has functional asymmetries, i.e., a dominance of ipsilateral pathways and of the right hemisphere in right-handers. To determine if acute right- or left-sided unilateral vestibular neuritis (VN) is associated with differential patterns of brain metabolism in areas representing the vestibular network and the visual-vestibular interaction, patients with acute VN (right n = 9; left n = 13) underwent resting state (18)F-FDG PET once in the acute phase and once 3 months later after central vestibular compensation. The contrast acute vs. chronic phase showed signal differences in contralateral vestibular areas and the inverse contrast in visual cortex areas, both more pronounced in VN right. In VN left additional regions were found in the cerebellar hemispheres and vermis bilaterally, accentuated in severe cases. In general, signal changes appeared more pronounced in patients with more severe vestibular deficits. Acute phase PET data of patients compared to that of age-matched healthy controls disclosed similarities to these patterns, thus permitting the interpretation that the signal changes in vestibular temporo-parietal areas reflect signal increases, and in visual areas, signal decreases. These data imply that brain activity in the acute phase of right- and left-sided VN exhibits different compensatory patterns, i.e., the dominant ascending input is shifted from the ipsilateral to the contralateral pathways, presumably due to the missing ipsilateral vestibular input. The visual-vestibular interaction patterns were preserved, but were of different prominence in each hemisphere and more pronounced in patients with right-sided failure and more severe vestibular deficits.

  1. Feature Detection in SAR Interferograms With Missing Data Displays Fault Slip Near El Mayor-Cucapah and South Napa Earthquakes

    NASA Astrophysics Data System (ADS)

    Parker, J. W.; Donnellan, A.; Glasscoe, M. T.; Stough, T.

    2015-12-01

    Edge detection identifies seismic or aseismic fault motion, as demonstrated in repeat-pass inteferograms obtained by the Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) program. But this identification, demonstrated in 2010, was not robust: for best results, it requires a flattened background image, interpolation into missing data (holes) and outliers, and background noise that is either sufficiently small or roughly white Gaussian. Proper treatment of missing data, bursting noise patches, and tiny noise differences at short distances apart from bursts are essential to creating an acceptably reliable method sensitive to small near-surface fractures. Clearly a robust method is needed for machine scanning of the thousands of UAVSAR repeat-pass interferograms for evidence of fault slip, landslides, and other local features: hand-crafted intervention will not do. Effective methods of identifying, removing and filling in bad pixels reveal significant features of surface fractures. A rich network of edges (probably fractures and subsidence) in difference images spanning the South Napa earthquake give way to a simple set of postseismically slipping faults. Coseismic El Mayor-Cucapah interferograms compared to post-seismic difference images show nearly disjoint patterns of surface fractures in California's Sonoran Desert; the combined pattern reveals a network of near-perpendicular, probably conjugate faults not mapped before the earthquake. The current algorithms for UAVSAR interferogram edge detections are shown to be effective in difficult environments, including agricultural (Napa, Imperial Valley) and difficult urban areas (Orange County.).

  2. Pattern Water Use Efficiency perspective on degradation and recovery of shrublands across Mediterranean to Arid transition zones

    NASA Astrophysics Data System (ADS)

    Shoshany, Maxim

    2017-04-01

    Shrublands cover a total of 12.7 million km2 , a considerable part of them along semi-arid to arid transition zones. Varying patterns of shrubs, grasses and barren land along such climatic gradients express the spatial dimension of climate change and human disturbance which attracted limited attention in the eco-geomorphic literature. Questions concerning relationships between rainfall, shrublands biomass and their patterns are fundamental for the understanding of these ecosystems response to the expected changes in water availability due to global warming and the increase in human disturbance to natural ecosystems following World population growth. While processes leading to the formation of patterns had attracted considerable attention, the spatial dimension of Water Use Efficiency (WUE) which is a parameter measuring ecosystems productivity in relation to water availability is severely missing. Relative shrub cover is a primary estimator of the fraction of water utilized for shrubs growth. Edge effects must be considered as well in fragmented ecosystems in general and in hot regions in particular since soil temperature in hot regions which frequently exceed 50oC during summer months decreases photosynthesis and productivity in plants bordering bare soil. This edge effect is decreasing with the increase in shrubs' height. Pattern Water Use Efficiency describes the combined effect of shrub cover, shrub height and shrub patches edge zone proportion on water use efficiency. In my presentation I will first present mapping od PWUEs across Mediterranean to arid transition zones in the Eastern Mediterranean. Then I will present several mathematical models describing PWUE for simulated patterns, searching for the spatial parameterization providing the highest sensitivity to patterns responses to changes in habitat conditions. Such simulations would allow us to discuss several PWUE strategies for shrublands recovery under the current scenarios of climate change and human driven degradation.

  3. Highlight removal based on the regional-projection fringe projection method

    NASA Astrophysics Data System (ADS)

    Qi, Zhaoshuai; Wang, Zhao; Huang, Junhui; Xing, Chao; Gao, Jianmin

    2018-04-01

    In fringe projection profilometry, highlight usually causes the saturation and blooming in captured fringes and reduces the measurement accuracy. To solve the problem, a regional-projection fringe projection (RP-FP) method is proposed. Regional projection patterns (RP patterns) are projected onto the tested object surface to avoid the saturation and blooming. Then, an image inpainting technique is employed to reconstruct the missing phases in the captured RP patterns and a complete surface of the tested object is obtained. Experiments verified the effectiveness of the proposed method. The method can be widely used in industrial inspections and quality controlling in mechanical and manufacturing industries.

  4. River catchment rainfall series analysis using additive Holt-Winters method

    NASA Astrophysics Data System (ADS)

    Puah, Yan Jun; Huang, Yuk Feng; Chua, Kuan Chin; Lee, Teang Shui

    2016-03-01

    Climate change is receiving more attention from researchers as the frequency of occurrence of severe natural disasters is getting higher. Tropical countries like Malaysia have no distinct four seasons; rainfall has become the popular parameter to assess climate change. Conventional ways that determine rainfall trends can only provide a general result in single direction for the whole study period. In this study, rainfall series were modelled using additive Holt-Winters method to examine the rainfall pattern in Langat River Basin, Malaysia. Nine homogeneous series of more than 25 years data and less than 10% missing data were selected. Goodness of fit of the forecasted models was measured. It was found that seasonal rainfall model forecasts are generally better than the monthly rainfall model forecasts. Three stations in the western region exhibited increasing trend. Rainfall in southern region showed fluctuation. Increasing trends were discovered at stations in the south-eastern region except the seasonal analysis at station 45253. Decreasing trend was found at station 2818110 in the east, while increasing trend was shown at station 44320 that represents the north-eastern region. The accuracies of both rainfall model forecasts were tested using the recorded data of years 2010-2012. Most of the forecasts are acceptable.

  5. Femoral head avascular necrosis: a frequently missed incidental finding on multidetector CT.

    PubMed

    Barille, M F; Wu, Jim S; McMahon, Colm J

    2014-03-01

    To determine the incidence of missed femoral head avascular necrosis (AVN) on pelvic computed tomography (CT) performed for clinical indications other than assessment for AVN. The study was a Health Insurance Portability and Accountability Act (HIPAA)-compliant retrospective study. The picture archiving and communication system (PACS) database was queried for patients with diagnosis of femoral head AVN on magnetic resonance imaging (MRI), who also underwent pelvic multidetector CT after or <30 days before the MRI examination. The MRI and CT images of 144 hips of 72 patients (39 patients with reported AVN on MRI and 33 age-matched controls; mean age = 60 years, 28 male, 44 female), were reviewed in consensus by two readers in a randomized, blinded manner. Using MRI-proven CT-visible AVN as a reference standard, the incidence of missed AVN on initial CT interpretation was determined. Readers confirmed AVN in 33 patients on the MRI images. Nine hips with AVN underwent joint replacement of the affected joint(s) prior to subsequent CT and were excluded. Forty-three MRI-proven AVN cases in 28 patients (15 bilateral, 13 unilateral) were available for analysis. The study readers diagnosed 35/43 (81%) MRI-proven AVN cases in 22/28 (79%) patients. Four of the 35 (11%) cases of MRI-proven, CT-visible AVN were prospectively reported in 3/22 (14%) patients at initial clinical interpretation, with a miss rate of 89% per hip and 86% per patient. Multidetector CT has high accuracy for detection of AVN; however, this is frequently missed as an incidental finding (89% missed in the present study). Assessment for signs of femoral AVN should be part of routine search pattern in interpretation of pelvic CT. Copyright © 2013 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  6. Missed losses loom larger than missed gains: Electrodermal reactivity to decision choices and outcomes in a gambling task.

    PubMed

    Wu, Yin; Van Dijk, Eric; Aitken, Mike; Clark, Luke

    2016-04-01

    Loss aversion is a defining characteristic of prospect theory, whereby responses are stronger to losses than to equivalently sized gains (Kahneman & Tversky Econometrica, 47, 263-291, 1979). By monitoring electrodermal activity (EDA) during a gambling task, in this study we examined physiological activity during risky decisions, as well as to both obtained (e.g., gains and losses) and counterfactual (e.g., narrowly missed gains and losses) outcomes. During the bet selection phase, EDA increased linearly with bet size, highlighting the role of somatic signals in decision-making under uncertainty in a task without any learning requirement. Outcome-related EDA scaled with the magnitudes of monetary wins and losses, and losses had a stronger impact on EDA than did equivalently sized wins. Narrowly missed wins (i.e., near-wins) and narrowly missed losses (i.e., near-losses) also evoked EDA responses, and the change of EDA as a function of the size of the missed outcome was modestly greater for near-losses than for near-wins, suggesting that near-losses have more impact on subjective value than do near-wins. Across individuals, the slope for choice-related EDA (as a function of bet size) correlated with the slope for outcome-related EDA as a function of both the obtained and counterfactual outcome magnitudes, and these correlations were stronger for loss and near-loss conditions than for win and near-win conditions. Taken together, these asymmetrical EDA patterns to objective wins and losses, as well as to near-wins and near-losses, provide a psychophysiological instantiation of the value function curve in prospect theory, which is steeper in the negative than in the positive domain.

  7. Reconstruction of Missing Pixels in Satellite Images Using the Data Interpolating Empirical Orthogonal Function (DINEOF)

    NASA Astrophysics Data System (ADS)

    Liu, X.; Wang, M.

    2016-02-01

    For coastal and inland waters, complete (in spatial) and frequent satellite measurements are important in order to monitor and understand coastal biological and ecological processes and phenomena, such as diurnal variations. High-frequency images of the water diffuse attenuation coefficient at the wavelength of 490 nm (Kd(490)) derived from the Korean Geostationary Ocean Color Imager (GOCI) provide a unique opportunity to study diurnal variation of the water turbidity in coastal regions of the Bohai Sea, Yellow Sea, and East China Sea. However, there are lots of missing pixels in the original GOCI-derived Kd(490) images due to clouds and various other reasons. Data Interpolating Empirical Orthogonal Function (DINEOF) is a method to reconstruct missing data in geophysical datasets based on Empirical Orthogonal Function (EOF). In this study, the DINEOF is applied to GOCI-derived Kd(490) data in the Yangtze River mouth and the Yellow River mouth regions, the DINEOF reconstructed Kd(490) data are used to fill in the missing pixels, and the spatial patterns and temporal functions of the first three EOF modes are also used to investigate the sub-diurnal variation due to the tidal forcing. In addition, DINEOF method is also applied to the Visible Infrared Imaging Radiometer Suite (VIIRS) on board the Suomi National Polar-orbiting Partnership (SNPP) satellite to reconstruct missing pixels in the daily Kd(490) and chlorophyll-a concentration images, and some application examples in the Chesapeake Bay and the Gulf of Mexico will be presented.

  8. Comparing the accuracy and precision of three techniques used for estimating missing landmarks when reconstructing fossil hominin crania.

    PubMed

    Neeser, Rudolph; Ackermann, Rebecca Rogers; Gain, James

    2009-09-01

    Various methodological approaches have been used for reconstructing fossil hominin remains in order to increase sample sizes and to better understand morphological variation. Among these, morphometric quantitative techniques for reconstruction are increasingly common. Here we compare the accuracy of three approaches--mean substitution, thin plate splines, and multiple linear regression--for estimating missing landmarks of damaged fossil specimens. Comparisons are made varying the number of missing landmarks, sample sizes, and the reference species of the population used to perform the estimation. The testing is performed on landmark data from individuals of Homo sapiens, Pan troglodytes and Gorilla gorilla, and nine hominin fossil specimens. Results suggest that when a small, same-species fossil reference sample is available to guide reconstructions, thin plate spline approaches perform best. However, if no such sample is available (or if the species of the damaged individual is uncertain), estimates of missing morphology based on a single individual (or even a small sample) of close taxonomic affinity are less accurate than those based on a large sample of individuals drawn from more distantly related extant populations using a technique (such as a regression method) able to leverage the information (e.g., variation/covariation patterning) contained in this large sample. Thin plate splines also show an unexpectedly large amount of error in estimating landmarks, especially over large areas. Recommendations are made for estimating missing landmarks under various scenarios. Copyright 2009 Wiley-Liss, Inc.

  9. Near Misses in Financial Trading: Skills for Capturing and Averting Error.

    PubMed

    Leaver, Meghan; Griffiths, Alex; Reader, Tom

    2018-05-01

    The aims of this study were (a) to determine whether near-miss incidents in financial trading contain information on the operator skills and systems that detect and prevent near misses and the patterns and trends revealed by these data and (b) to explore if particular operator skills and systems are found as important for avoiding particular types of error on the trading floor. In this study, we examine a cohort of near-miss incidents collected from a financial trading organization using the Financial Incident Analysis System and report on the nontechnical skills and systems that are used to detect and prevent error in this domain. One thousand near-miss incidents are analyzed using distribution, mean, chi-square, and associative analysis to describe the data; reliability is provided. Slips/lapses (52%) and human-computer interface problems (21%) often occur alone and are the main contributors to error causation, whereas the prevention of error is largely a result of teamwork (65%) and situation awareness (46%) skills. No matter the cause of error, situation awareness and teamwork skills are used most often to detect and prevent the error. Situation awareness and teamwork skills appear universally important as a "last line" of defense for capturing error, and data from incident-monitoring systems can be analyzed in a fashion more consistent with a "Safety-II" approach. This research provides data for ameliorating risk within financial trading organizations, with implications for future risk management programs and regulation.

  10. Dark matter particle spectroscopy at the LHC: generalizing M T2 to asymmetric event topologies

    NASA Astrophysics Data System (ADS)

    Konar, Partha; Kong, Kyoungchul; Matchev, Konstantin T.; Park, Myeonghun

    2010-04-01

    We consider SUSY-like missing energy events at hadron colliders and critically examine the common assumption that the missing energy is the result of two identical missing particles. In order to experimentally test this hypothesis, we generalize the subsystem M T2 variable to the case of asymmetric event topologies, where the two SUSY decay chains terminate in different “children” particles. In this more general approach, the endpoint M T2( max) of the M T2 distribution now gives the mass {tilde M_p}left( {tilde M_c^{(a)},tilde M_c^{(b)}} right) of the parent particles as a function of two input children masses tilde M_c^{(a)} and tilde M_c^{(b)} . We propose two methods for an independent determination of the individual children masses M ( a) c and M ( b) c . First, in the presence of upstream transverse momentum PUTM the corresponding function {tilde M_p}left( {tilde M_c^{(a)},tilde M_c^{(b)},{P_{text{UTM}}}} right) is independent of PUTM at precisely the right values of the children masses. Second, the previously discussed M T2 “kink” is now generalized to a “ridge” on the 2-dimensional surface {tilde M_p}left( {tilde M_c^{(a)},tilde M_c^{(b)}} right) . As we show in several examples, quite often there is a special point along that ridge which marks the true values of the children masses. Our results allow collider experiments to probe a multi-component dark matter sector directly and without any theoretical prejudice.

  11. 198 AAAAI Survey on Immunotherapy Practice Patterns Concerning Dosing, Dose-Adjustment after Missed Doses and Duration of Immunotherapy

    PubMed Central

    Linnemann, Désirée Larenas; Gupta, Payel; Mithani, Sima; Ponda, Punita

    2012-01-01

    Background Several practical issues dealing with the exact application of allergen immunotherapy (AIT) among European and US allergists are not well known. Guidelines on AIT give recommendations and suggestions for only some of them. We present this unique survey with worldwide response. Methods The AAAAI immunotherapy committee conducted a web-based practice patterns survey (program: Survey Monkey) among all members in&outside US on dosing, dose-adjustment after missed doses and duration of AIT. Results 1201 Returned questionnaires (almost 25% response rate). 21% were non-US-Canada members. Maintenance doses in USCan are (mean/median): Dermatophagoides farinae (Df) combined with Dermatophagoides pteronyssinus (Dpt): 2155/1000AU; Df solo 2484/1000AU. Dpt when combined with Df 1937/1000AU; Dpt solo: 2183/1000AU.Cat 3224/2000BAU. Grass 11,410/4000BAU. 57-65% of the dosing falls within the recommended Practice Parameters recommended ranges. Non-USCan allergists expressed maintenance doses in many different units making analysis impossible. Dose-adjustment after missed doses is based on ‘time elapsed since the last applied dose’ by 77% of USCan and 58% of non-USCan allergists and on ‘time since missed scheduled dose’ by the rest. Doses are adjusted when a patient comes in more than 14 d/5 wk after the last administration at build-up/maintenance by both USCan and non-USCan colleagues. The mostly followed dose-adjustment schedules after 1, 2, 3 missed doses are: Build-up: repeat last dose, reduce by one dose, reduce by 2 doses; maintenance: reduce by one dose, reduce by 2 doses, reduce by 3 doses. 26% uses a different approach reducing doses by a certain percentage or volume. AIT is restarted after a gap in build-up of >30 days and of >12 weeks during maintenance in both groups (median). Outside USCan AIT is prescribed for 3 years (Median). However, 75% of USCan allergists prescribes AIT for 5 years. Main reasons why to continue AIT beyond 5 years: ‘symptoms came back after stopping’ or “patient afraid to relapse.” Conclusions These results show regional differences on some points (especially AIT duration) and they suggest in which direction to plan further research in 2 areas to establish universal dose-adjustment plans for missed applications and define the usefulness (or lack of) of long-term AIT. Moreover, there is still room for improvement in the way AIT is dosed.

  12. Assessment of BSRN radiation records for the computation of monthly means

    NASA Astrophysics Data System (ADS)

    Roesch, A.; Wild, M.; Ohmura, A.; Dutton, E. G.; Long, C. N.; Zhang, T.

    2011-02-01

    The integrity of the Baseline Surface Radiation Network (BSRN) radiation monthly averages are assessed by investigating the impact on monthly means due to the frequency of data gaps caused by missing or discarded high time resolution data. The monthly statistics, especially means, are considered to be important and useful values for climate research, model performance evaluations and for assessing the quality of satellite (time- and space-averaged) data products. The study investigates the spread in different algorithms that have been applied for the computation of monthly means from 1-min values. The paper reveals that the computation of monthly means from 1-min observations distinctly depends on the method utilized to account for the missing data. The intra-method difference generally increases with an increasing fraction of missing data. We found that a substantial fraction of the radiation fluxes observed at BSRN sites is either missing or flagged as questionable. The percentage of missing data is 4.4%, 13.0%, and 6.5% for global radiation, direct shortwave radiation, and downwelling longwave radiation, respectively. Most flagged data in the shortwave are due to nighttime instrumental noise and can reasonably be set to zero after correcting for thermal offsets in the daytime data. The study demonstrates that the handling of flagged data clearly impacts on monthly mean estimates obtained with different methods. We showed that the spread of monthly shortwave fluxes is generally clearly higher than for downwelling longwave radiation. Overall, BSRN observations provide sufficient accuracy and completeness for reliable estimates of monthly mean values. However, the value of future data could be further increased by reducing the frequency of data gaps and the number of outliers. It is shown that two independent methods for accounting for the diurnal and seasonal variations in the missing data permit consistent monthly means to within less than 1 W m-2 in most cases. The authors suggest using a standardized method for the computation of monthly means which addresses diurnal variations in the missing data in order to avoid a mismatch of future published monthly mean radiation fluxes from BSRN. The application of robust statistics would probably lead to less biased results for data records with frequent gaps and/or flagged data and outliers. The currently applied empirical methods should, therefore, be completed by the development of robust methods.

  13. Characterizing and Managing Missing Structured Data in Electronic Health Records: Data Analysis.

    PubMed

    Beaulieu-Jones, Brett K; Lavage, Daniel R; Snyder, John W; Moore, Jason H; Pendergrass, Sarah A; Bauer, Christopher R

    2018-02-23

    Missing data is a challenge for all studies; however, this is especially true for electronic health record (EHR)-based analyses. Failure to appropriately consider missing data can lead to biased results. While there has been extensive theoretical work on imputation, and many sophisticated methods are now available, it remains quite challenging for researchers to implement these methods appropriately. Here, we provide detailed procedures for when and how to conduct imputation of EHR laboratory results. The objective of this study was to demonstrate how the mechanism of missingness can be assessed, evaluate the performance of a variety of imputation methods, and describe some of the most frequent problems that can be encountered. We analyzed clinical laboratory measures from 602,366 patients in the EHR of Geisinger Health System in Pennsylvania, USA. Using these data, we constructed a representative set of complete cases and assessed the performance of 12 different imputation methods for missing data that was simulated based on 4 mechanisms of missingness (missing completely at random, missing not at random, missing at random, and real data modelling). Our results showed that several methods, including variations of Multivariate Imputation by Chained Equations (MICE) and softImpute, consistently imputed missing values with low error; however, only a subset of the MICE methods was suitable for multiple imputation. The analyses we describe provide an outline of considerations for dealing with missing EHR data, steps that researchers can perform to characterize missingness within their own data, and an evaluation of methods that can be applied to impute clinical data. While the performance of methods may vary between datasets, the process we describe can be generalized to the majority of structured data types that exist in EHRs, and all of our methods and code are publicly available. ©Brett K Beaulieu-Jones, Daniel R Lavage, John W Snyder, Jason H Moore, Sarah A Pendergrass, Christopher R Bauer. Originally published in JMIR Medical Informatics (http://medinform.jmir.org), 23.02.2018.

  14. Past and future implications of near-misses and their emotional consequences.

    PubMed

    Zhang, Qiyuan; Covey, Judith

    2014-01-01

    The Reflection and Evaluation Model (REM) of comparative thinking predicts that temporal perspective could moderate people's emotional reactions to close counterfactuals following near-misses (Markman & McMullen, 2003). The experiments reported in this paper tested predictions derived from this theory by examining how people's emotional reactions to a near-miss at goal during a football match (Experiment 1) or a close score in a TV game show (Experiment 2) depended on the level of perceived future possibility. In support of the theory it was found that the presence of future possibility enhanced affective assimilation (e.g., if the near-miss occurred at the beginning of the game the players who had nearly scored were hopeful of future success) whereas the absence of future possibility enhanced affective contrast (e.g., if the near-miss occurred at the end of the game the players who had nearly scored were disappointed about missing an opportunity). Furthermore the experiments built upon our theoretical understanding by exploring the mechanisms which produce assimilation and contrast effects. In Experiment 1 we examined the incidence of present-oriented or future-oriented thinking, and in Experiment 2 we examined the mediating role of counterfactual thinking in the observed effect of proximity on emotions by testing whether stronger counterfactuals (measured using counterfactual probability estimates) produce bigger contrast and assimilation effects. While the results of these investigations generally support the REM, they also highlight the necessity to consider other psychological mechanisms (e.g., social comparison), in addition to counterfactual thinking, that might contribute to the emotional consequences of near-miss outcomes.

  15. 1. General view of bridge looking north. This is the ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. General view of bridge looking north. This is the only suspension bridge in Cleveland. It was designed by Wilbur J. Watson and Associates, Consulting Engineers. Sections of the Wooden deck are missing, and the bridge is no longer used. - Sidaway Avenue Footbridge, Jackowo & Garden Valley neighborhood Vicinity, Cleveland, Cuyahoga County, OH

  16. Case Study Effectiveness in a Team-Teaching and General-Education Environment

    ERIC Educational Resources Information Center

    Olorunnisola, Anthony A.; Ramasubramanian, Srividya; Russill, Chris; Dumas, Josephine

    2003-01-01

    This paper examines the effectiveness of the case study method in a team-teaching environment designed to augment a large capstone communications course that satisfies general education requirements. Results from a survey revealed that the use of case study enhanced the otherwise missing connection between the large lecture and the recitation…

  17. The Utility of Interaction Analysis for Generalizing Characteristics of Science Classrooms

    ERIC Educational Resources Information Center

    Crippen, Kent J.; Sangueza, Cheryl R.

    2013-01-01

    Validating and generalizing from holistic observation protocols of classroom practice have proven difficult. These tools miss crucial classroom characteristics, like the type of instruction, the organization of learners, and the level of cognitive engagement that occur differentially in the time span of a lesson. As a result, this study examined…

  18. Handling missing rows in multi-omics data integration: multiple imputation in multiple factor analysis framework.

    PubMed

    Voillet, Valentin; Besse, Philippe; Liaubet, Laurence; San Cristobal, Magali; González, Ignacio

    2016-10-03

    In omics data integration studies, it is common, for a variety of reasons, for some individuals to not be present in all data tables. Missing row values are challenging to deal with because most statistical methods cannot be directly applied to incomplete datasets. To overcome this issue, we propose a multiple imputation (MI) approach in a multivariate framework. In this study, we focus on multiple factor analysis (MFA) as a tool to compare and integrate multiple layers of information. MI involves filling the missing rows with plausible values, resulting in M completed datasets. MFA is then applied to each completed dataset to produce M different configurations (the matrices of coordinates of individuals). Finally, the M configurations are combined to yield a single consensus solution. We assessed the performance of our method, named MI-MFA, on two real omics datasets. Incomplete artificial datasets with different patterns of missingness were created from these data. The MI-MFA results were compared with two other approaches i.e., regularized iterative MFA (RI-MFA) and mean variable imputation (MVI-MFA). For each configuration resulting from these three strategies, the suitability of the solution was determined against the true MFA configuration obtained from the original data and a comprehensive graphical comparison showing how the MI-, RI- or MVI-MFA configurations diverge from the true configuration was produced. Two approaches i.e., confidence ellipses and convex hulls, to visualize and assess the uncertainty due to missing values were also described. We showed how the areas of ellipses and convex hulls increased with the number of missing individuals. A free and easy-to-use code was proposed to implement the MI-MFA method in the R statistical environment. We believe that MI-MFA provides a useful and attractive method for estimating the coordinates of individuals on the first MFA components despite missing rows. MI-MFA configurations were close to the true configuration even when many individuals were missing in several data tables. This method takes into account the uncertainty of MI-MFA configurations induced by the missing rows, thereby allowing the reliability of the results to be evaluated.

  19. Missing link in the evolution of Hox clusters.

    PubMed

    Ogishima, Soichi; Tanaka, Hiroshi

    2007-01-31

    Hox cluster has key roles in regulating the patterning of the antero-posterior axis in a metazoan embryo. It consists of the anterior, central and posterior genes; the central genes have been identified only in bilaterians, but not in cnidarians, and are responsible for archiving morphological complexity in bilaterian development. However, their evolutionary history has not been revealed, that is, there has been a "missing link". Here we show the evolutionary history of Hox clusters of 18 bilaterians and 2 cnidarians by using a new method, "motif-based reconstruction", examining the gain/loss processes of evolutionarily conserved sequences, "motifs", outside the homeodomain. We successfully identified the missing link in the evolution of Hox clusters between the cnidarian-bilaterian ancestor and the bilaterians as the ancestor of the central genes, which we call the proto-central gene. Exploring the correspondent gene with the proto-central gene, we found that one of the acoela Hox genes has the same motif repertory as that of the proto-central gene. This interesting finding suggests that the acoela Hox cluster corresponds with the missing link in the evolution of the Hox cluster between the cnidarian-bilaterian ancestor and the bilaterians. Our findings suggested that motif gains/diversifications led to the explosive diversity of the bilaterian body plan.

  20. Modelling Agency in HIV Treatment Decision-Making

    ERIC Educational Resources Information Center

    Moore, Alison

    2005-01-01

    In applying linguistics to the task of analysing how agentivity is construed through verbal interaction, scholars often equate social agency with grammatical agency, and in particular with the grammar of transitivity. The difficulty I want to address in this paper is that we may miss other important, systematic and contrastive patterning in the…

  1. Recommendations of Transgender Students, Staff, and Faculty in the USA for Improving College Campuses

    ERIC Educational Resources Information Center

    Seelman, Kristie L.

    2014-01-01

    Research indicates that transgender individuals frequently experience marginalisation and interpersonal victimisation within college and university settings. Missing from the literature is a discussion of what can be done to address such patterns in higher education, based upon empirical data gathered from transgender and gender non-conforming…

  2. Top Ten Reasons To Use InDesign for Scholastic Media.

    ERIC Educational Resources Information Center

    Communication: Journalism Education Today, 2003

    2003-01-01

    Explains that Adobe InDesign 2.0 moves desktop to new possibilities because it combines the best of modern graphics techniques. Provides explanations of the following aspects of InDesign: drop shadow; align objects; define styles; type on a path; grids; accessible patterns; gradients; create outlines; indexing; and shows missing point. (PM)

  3. Missing Elements in the Discussion of Teacher Shortages

    ERIC Educational Resources Information Center

    Cowan, James; Goldhaber, Dan; Hayes, Kyle; Theobald, Roddy

    2016-01-01

    Though policymakers are increasingly concerned about teacher shortages in U.S. public schools, the national discussion does not reflect historical patterns of the supply of and demand for newly minted teachers. Specifically, the production of teacher candidates has increased steadily since the mid-1980s, and only about half of graduating teacher…

  4. Comparison of Imputation Procedures for Replacing Denied-access Plots

    Treesearch

    Susan L. King

    2005-01-01

    In forest inventories, missing plots are caused by hazardous terrain, inaccessible locations, or denied access. Maryland had a large number of denied-access plots in the latest periodic inventory conducted by the Northeastern Forest Inventory and Analysis unit. The denial pattern, which can introduce error into the estimates, was investigated by dropping the 1999...

  5. Air Quality and Early-Life Mortality: Evidence from Indonesia's Wildfires

    ERIC Educational Resources Information Center

    Jayachandran, Seema

    2009-01-01

    Smoke from massive wildfires blanketed Indonesia in late 1997. This paper examines the impact that this air pollution (particulate matter) had on fetal, infant, and child mortality. Exploiting the sharp timing and spatial patterns of the pollution and inferring deaths from "missing children" in the 2000 Indonesian Census, I find that the…

  6. Exploring the Limitations of Measures of Students' Socioeconomic Status (SES)

    ERIC Educational Resources Information Center

    Dickinson, Emily R.; Adelson, Jill L.

    2014-01-01

    This study uses a nationally representative student dataset to explore the limitations of commonly used measures of socioeconomic status (SES). Among the identified limitations are patterns of missing data that conflate the traditional conceptualization of SES with differences in family structure that have emerged in recent years and a lack of…

  7. Nonsyndromic tooth agenesis patterns and associated developmental dental anomalies: a literature review with radiographic illustrations.

    PubMed

    Agarwal, P; Vinuth, D P; Dube, G; Dube, P

    2013-01-01

    Tooth agenesis is one of the most intriguing phenomena, because it is frequently associated with other oral anomalies, structural variations and malformations of other teeth, late eruption, transposition and crowding. The diagnosis can be quite challenging as radiographic examination is critical for the diagnosis but not always possible and the late developing teeth may be sometimes scored developmentally missing. Accurate diagnosis therefore requires radiographic, clinical, and dental cast examinations. It is an important clinical and public health problem. Patients with missing permanent teeth may suffer from a reduced chewing ability, inarticulate pronunciation, and an unfavorable aesthetic appearance. Clinically, early diagnosis of a dental anomaly can alert the clinician to the possible development of other associated dental anomalies in the same patient or family, and avoid the possible sequelae. Understanding of tooth agenesis patterns and their impact on diagnosis, prevention, and eventually therapeutics are becoming integral parts of comprehensive dental care. Dental examination with radiographic screening of hypodontia in early childhood should be emphasized as part of public oral health policy to allow early diagnosis and timely intervention.

  8. Comparative anatomy, homologies and evolution of the pectoral and forelimb musculature of tetrapods with special attention to extant limbed amphibians and reptiles

    PubMed Central

    Abdala, Virginia; Diogo, Rui

    2010-01-01

    The main aim of the present work is to synthesize the information obtained from our dissections of the pectoral and forelimb muscles of representative members of the major extant taxa of limbed amphibians and reptiles and from our review of the literature, in order to provide an account of the comparative anatomy, homologies and evolution of these muscles in the Tetrapoda. The pectoral and forelimb musculature of all these major taxa conform to a general pattern that seems to have been acquired very early in the evolutionary history of tetrapods. Although some muscles are missing in certain taxa, and a clear departure from this general pattern is obviously present in derived groups such as birds, the same overall configuration is easily distinguishable in these taxa. Among the most notable anatomical differences between the groups, one that seems to have relevant evolutionary and functional implications, concerns the distal insertion points of the forearm musculature. In tetrapods, the muscles of the radial and ulnar complexes of the forearm are pleisomorphically mainly inserted onto the radius/ulna or onto the more proximal carpal bones, but in mammals some of these muscles insert more distally onto bones such as the metacarpals. Interestingly, a similar trend towards a more distal insertion of these muscles is also found in some non-mammalian tetrapod taxa, such as some anurans (e.g. Phyllomedusa). This may be correlated with the acquisition of more subtle digital movement abilities in these latter taxa. PMID:20807270

  9. Sequential Learning and Recognition of Comprehensive Behavioral Patterns Based on Flow of People

    NASA Astrophysics Data System (ADS)

    Gibo, Tatsuya; Aoki, Shigeki; Miyamoto, Takao; Iwata, Motoi; Shiozaki, Akira

    Recently, surveillance cameras have been set up everywhere, for example, in streets and public places, in order to detect irregular situations. In the existing surveillance systems, as only a handful of surveillance agents watch a large number of images acquired from surveillance cameras, there is a possibility that they may miss important scenes such as accidents or abnormal incidents. Therefore, we propose a method for sequential learning and the recognition of comprehensive behavioral patterns in crowded places. First, we comprehensively extract a flow of people from input images by using optical flow. Second, we extract behavioral patterns on the basis of change-point detection of the flow of people. Finally, in order to recognize an observed behavioral pattern, we draw a comparison between the behavioral pattern and previous behavioral patterns in the database. We verify the effectiveness of our approach by placing a surveillance camera on a campus.

  10. Communication at the interface between hospitals and primary care - a general practice audit of hospital discharge summaries.

    PubMed

    Belleli, Esther; Naccarella, Lucio; Pirotta, Marie

    2013-12-01

    Timeliness and quality of hospital discharge summaries are crucial for patient safety and efficient health service provision after discharge. We audited receipt rates, timeliness and the quality of discharge summaries for 49 admissions among 38 patients in an urban general practice. For missing discharge summaries, a hospital medical record search was performed. Discharge summaries were received for 92% of identified admissions; 73% were received within three days and 55% before the first post-discharge visit to the general practitioner (GP). Administrative information and clinical content, including diagnosis, treatment and follow-up plans, were well reported. However, information regarding tests, referrals and discharge medication was often missing; 57% of summaries were entirely typed and 13% had legibility issues. Completion rates were good but utility was compromised by delays, content omissions and formatting. Digital searching enables extraction of information from rich existing datasets contained in GP records for accurate measurement of discharge summary receipt rate and timing.

  11. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Latychevskaia, Tatiana, E-mail: tatiana@physik.uzh.ch; Fink, Hans-Werner; Chushkin, Yuriy

    Coherent diffraction imaging is a high-resolution imaging technique whose potential can be greatly enhanced by applying the extrapolation method presented here. We demonstrate the enhancement in resolution of a non-periodical object reconstructed from an experimental X-ray diffraction record which contains about 10% missing information, including the pixels in the center of the diffraction pattern. A diffraction pattern is extrapolated beyond the detector area and as a result, the object is reconstructed at an enhanced resolution and better agreement with experimental amplitudes is achieved. The optimal parameters for the iterative routine and the limits of the extrapolation procedure are discussed.

  12. Using forbidden ordinal patterns to detect determinism in irregularly sampled time series.

    PubMed

    Kulp, C W; Chobot, J M; Niskala, B J; Needhammer, C J

    2016-02-01

    It is known that when symbolizing a time series into ordinal patterns using the Bandt-Pompe (BP) methodology, there will be ordinal patterns called forbidden patterns that do not occur in a deterministic series. The existence of forbidden patterns can be used to identify deterministic dynamics. In this paper, the ability to use forbidden patterns to detect determinism in irregularly sampled time series is tested on data generated from a continuous model system. The study is done in three parts. First, the effects of sampling time on the number of forbidden patterns are studied on regularly sampled time series. The next two parts focus on two types of irregular-sampling, missing data and timing jitter. It is shown that forbidden patterns can be used to detect determinism in irregularly sampled time series for low degrees of sampling irregularity (as defined in the paper). In addition, comments are made about the appropriateness of using the BP methodology to symbolize irregularly sampled time series.

  13. History of yogurt and current patterns of consumption.

    PubMed

    Fisberg, Mauro; Machado, Rachel

    2015-08-01

    Yogurt has been a part of the human diet for several millennia and goes by many names throughout the world. The word "yogurt" is believed to have come from the Turkish word "yoğurmak," which means to thicken, coagulate, or curdle. While references to the health-promoting properties of yogurt date back to 6000 BC in Indian Ayurvedic scripts, it was not until the 20th century that Stamen Grigorov, a Bulgarian medical student, attributed the benefits to lactic acid bacteria. Today, most yogurt is fermented milk that is acidified with viable and well-defined bacteria (Lactobacillus bulgaricus and Streptococcus thermophiles). While patterns of yogurt consumption vary greatly from country to country, consumption is generally low. In the United States and Brazil, for example, only 6% of the population consume yogurt on a daily basis. Low consumption of yogurt represents a missed opportunity to contribute to a healthy lifestyle, as yogurt provides a good to excellent source of highly bioavailable protein and an excellent source of calcium as well as a source of probiotics that may provide a range of health benefits. © The Author(s) 2015. Published by Oxford University Press on behalf of the International Life Sciences Institute. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  14. Similar but Different: Dynamic Social Network Analysis Highlights Fundamental Differences between the Fission-Fusion Societies of Two Equid Species, the Onager and Grevy’s Zebra

    PubMed Central

    Rubenstein, Daniel I.; Sundaresan, Siva R.; Fischhoff, Ilya R.; Tantipathananandh, Chayant; Berger-Wolf, Tanya Y.

    2015-01-01

    Understanding why animal societies take on the form that they do has benefited from insights gained by applying social network analysis to patterns of individual associations. Such analyses typically aggregate data over long time periods even though most selective forces that shape sociality have strong temporal elements. By explicitly incorporating the temporal signal in social interaction data we re-examine the network dynamics of the social systems of the evolutionarily closely-related Grevy’s zebras and wild asses that show broadly similar social organizations. By identifying dynamic communities, previously hidden differences emerge: Grevy’s zebras show more modularity than wild asses and in wild asses most communities consist of solitary individuals; and in Grevy’s zebras, lactating females show a greater propensity to switch communities than non-lactating females and males. Both patterns were missed by static network analyses and in general, adding a temporal dimension provides insights into differences associated with the size and persistence of communities as well as the frequency and synchrony of their formation. Dynamic network analysis provides insights into the functional significance of these social differences and highlights the way dynamic community analysis can be applied to other species. PMID:26488598

  15. Optimal simultaneous superpositioning of multiple structures with missing data.

    PubMed

    Theobald, Douglas L; Steindel, Phillip A

    2012-08-01

    Superpositioning is an essential technique in structural biology that facilitates the comparison and analysis of conformational differences among topologically similar structures. Performing a superposition requires a one-to-one correspondence, or alignment, of the point sets in the different structures. However, in practice, some points are usually 'missing' from several structures, for example, when the alignment contains gaps. Current superposition methods deal with missing data simply by superpositioning a subset of points that are shared among all the structures. This practice is inefficient, as it ignores important data, and it fails to satisfy the common least-squares criterion. In the extreme, disregarding missing positions prohibits the calculation of a superposition altogether. Here, we present a general solution for determining an optimal superposition when some of the data are missing. We use the expectation-maximization algorithm, a classic statistical technique for dealing with incomplete data, to find both maximum-likelihood solutions and the optimal least-squares solution as a special case. The methods presented here are implemented in THESEUS 2.0, a program for superpositioning macromolecular structures. ANSI C source code and selected compiled binaries for various computing platforms are freely available under the GNU open source license from http://www.theseus3d.org. dtheobald@brandeis.edu Supplementary data are available at Bioinformatics online.

  16. Missed opportunities for earlier diagnosis of HIV in patients who presented with advanced HIV disease: a retrospective cohort study

    PubMed Central

    Levy, Itzchak; Maor, Yasmin; Mahroum, Naim; Olmer, Liraz; Wieder, Anat; Litchevski, Vladislav; Mor, Orna; Rahav, Galia

    2016-01-01

    Objective To quantify and characterise missed opportunities for earlier HIV diagnosis in patients diagnosed with advanced HIV. Design A retrospective observational cohort study. Setting A central tertiary medical centre in Israel. Measures The proportion of patients with advanced HIV, the proportion of missed opportunities to diagnose them earlier, and the rate of clinical indicator diseases (CIDs) in those patients. Results Between 2010 and 2015, 356 patients were diagnosed with HIV, 118 (33.4%) were diagnosed late, 57 (16%) with advanced HIV disease. Old age (OR=1.45 (95% CI 1.16 to 1.74)) and being heterosexual (OR=2.65 (95% CI 1.21 to 5.78)) were significant risk factors for being diagnosed late. All patients with advanced disease had at least one CID that did not lead to an HIV test in the 5 years prior to AIDS diagnosis. The median time between CID and AIDS diagnosis was 24 months (IQR 10–30). 60% of CIDs were missed by a general practitioner and 40% by a specialist. Conclusions Missed opportunities to early diagnosis of HIV occur in primary and secondary care. Lack of national guidelines, lack of knowledge regarding CIDs and communication barriers with patients may contribute to a late diagnosis of HIV. PMID:28186940

  17. The association between missing teeth and non-alcoholic fatty liver disease in adults.

    PubMed

    Qiao, Feng; Fu, Kaiyu; Zhang, Qing; Liu, Li; Meng, Ge; Wu, Hongmei; Xia, Yang; Bao, Xue; Gu, Yeqing; Shi, Hongbin; Sun, Shaomei; Wang, Xing; Zhou, Ming; Jia, Qiyu; Song, Kun; Niu, Kaijun

    2018-05-19

    Long-term oral chronic inflammatory process is closely related to systemic inflammation, which is a main mechanism involved in non-alcoholic fatty liver disease (NAFLD). Tooth loss could reflect the accumulation of oral local inflammation, implying that number of missing teeth may associate with NAFLD. This study evaluated the association between missing teeth and presence of NAFLD in a general population. A cross-sectional study of 24,470 adults was carried out from the Tianjin Chronic Low-grade Systemic Inflammation and Health Cohort Study. The self-reported number of missing teeth (excluding third molars) was recorded and classified into four categories: 0, 1-2, 3-5, and ≥6. The NAFLD was diagnosed by the liver ultrasonography. Associations were analyzed by adjusted multivariable logistic regression. The multivariable-adjusted odds ratios (95% confidence interval) of NAFLD across the categories of missing teeth were as follows: in males, 1.00(reference), 1.04(0.93-1.16), 1.06(0.90-1.24), and 1.40(1.09-1.81) (P for trend=0.04); in females, 1.00(reference), 0.98(0.83-1.15), 1.11(0.90-1.37), and 1.07(0.77-1.48) (P for trend=0.45). The number of missing teeth was associated with a higher presence of NAFLD in males but not females. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  18. 76 FR 3561 - Airworthiness Directives; The Boeing Company Model 777-200 and -300 Series Airplanes Equipped...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-20

    ... proposed AD, contact Boeing Commercial Airplanes, Attention: Data & Services Management, P.O. Box 3707, MC... is cracked, has gaps, is loose, or is missing; repetitive general visual inspections of click bond... sealant Doing an NDT and general visual inspection for thermal degradation of the exposed T/R inner wall...

  19. Math Avoidance: A Barrier to American Indian Science Education and Science Careers.

    ERIC Educational Resources Information Center

    Green, Rayna

    1978-01-01

    For American Indian students, math anxiety and math avoidance are the most serious obstacles to general education and to the choice of scientific careers. Indian students interviewed generally exhibited fear and loathing of mathematics and a major lack of basic skills which were caused by a missing or negative impression of the mathematics…

  20. Access to Information About Missing Children Act of 2012

    THOMAS, 112th Congress

    Sen. Klobuchar, Amy [D-MN

    2011-01-31

    Senate - 08/02/2012 Placed on Senate Legislative Calendar under General Orders. Calendar No. 487. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

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

    PubMed

    Shen, Chung-Wei; Chen, Yi-Hau

    2015-10-01

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

  2. Consent process for US-based family reference DNA samples.

    PubMed

    Katsanis, Sara H; Snyder, Lindsey; Arnholt, Kelly; Mundorff, Amy Z

    2018-01-01

    DNA collection from family members of the missing is a tenet for missing persons' and mass fatality investigations. Procedures for consenting family members are disparate, depending on the context supporting the reason for sample collection. While guidelines and best practices have been developed for handling mass fatalities and for identification of the missing, these guidelines do not address standard consent practices for living family members of potential victims. We examined the relevant U.S. laws, international guidelines and best practices, sampled consent forms currently used for DNA collection of family members, and drafted model language for a consent form to communicate the required and recommended information. We modeled the consent form on biobank consenting practices and tested the consent language among students and the general population for constructive feedback and readability. We also asked respondents to consider the options for DNA collection and either hypothetically agree or disagree. The model language presented here highlights information important to relay in consent processes and can serve as a foundation for future consent practices in mass fatalities and missing persons' investigations. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Flux measurements of volatile organic compounds from an urban landscape

    NASA Astrophysics Data System (ADS)

    Velasco, E.; Lamb, B.; Pressley, S.; Allwine, E.; Westberg, H.; Jobson, B. T.; Alexander, M.; Prazeller, P.; Molina, L.; Molina, M.

    2005-10-01

    Direct measurements of volatile organic compound (VOC) emissions that include all sources in urban areas are a missing requirement to evaluate emission inventories and constrain current photochemical modelling practices. Here we demonstrate the use of micrometeorological techniques coupled with fast-response sensors to measure urban VOC fluxes from a neighbourhood of Mexico City, where the spatial variability of surface cover and roughness is high. Fluxes of olefins, methanol, acetone, toluene and C2-benzenes were measured and compared with the local gridded emissions inventory. VOC fluxes exhibited a clear diurnal pattern with a strong relationship to vehicular traffic. Recent photochemical modelling results suggest that VOC emissions are significantly underestimated in Mexico City, but for the olefin class, toluene, C2-benzenes, and acetone fluxes measured in this work, the results show general agreement with the gridded emissions inventory. While these measurements do not address the full suite of VOC emissions, the comparison with the inventory suggests that other explanations may be needed to explain the photochemical modelling results.

  4. The Costs and Benefits of Testing and Guessing on Recognition Memory

    PubMed Central

    Huff, Mark J.; Balota, David A.; Hutchison, Keith A.

    2016-01-01

    We examined whether two types of interpolated tasks (i.e., retrieval-practice via free recall or guessing a missing critical item) improved final recognition for related and unrelated word lists relative to restudying or completing a filler task. Both retrieval-practice and guessing tasks improved correct recognition relative to restudy and filler tasks, particularly when study lists were semantically related. However, both retrieval practice and guessing also generally inflated false recognition for the non-presented critical words. These patterns were found when final recognition was completed during a short delay within the same experimental session (Experiment 1) and following a 24-hr delay (Experiment 2). In Experiment 3, task instructions were presented randomly after each list to determine whether retrieval-practice and guessing effects were influenced by task-expectancy processes. In contrast to Experiments 1 and 2, final recognition following retrieval practice and guessing was equivalent to restudy, suggesting that the observed retrieval-practice and guessing advantages were in part due to preparatory task-based processing during study. PMID:26950490

  5. Comprehensive histological evaluation of bone implants

    PubMed Central

    Rentsch, Claudia; Schneiders, Wolfgang; Manthey, Suzanne; Rentsch, Barbe; Rammelt, Stephan

    2014-01-01

    To investigate and assess bone regeneration in sheep in combination with new implant materials classical histological staining methods as well as immunohistochemistry may provide additional information to standard radiographs or computer tomography. Available published data of bone defect regenerations in sheep often present none or sparely labeled histological images. Repeatedly, the exact location of the sample remains unclear, detail enlargements are missing and the labeling of different tissues or cells is absent. The aim of this article is to present an overview of sample preparation, staining methods and their benefits as well as a detailed histological description of bone regeneration in the sheep tibia. General histological staining methods like hematoxylin and eosin, Masson-Goldner trichrome, Movat’s pentachrome and alcian blue were used to define new bone formation within a sheep tibia critical size defect containing a polycaprolactone-co-lactide (PCL) scaffold implanted for 3 months (n = 4). Special attention was drawn to describe the bone healing patterns down to cell level. Additionally one histological quantification method and immunohistochemical staining methods are described. PMID:24504113

  6. Web-based health resources at US colleges: early patterns and missed opportunities in preventive health.

    PubMed

    Jue, J Jane S; Metlay, Joshua P

    2011-11-01

    Web-based health resources on college websites have the potential to reach a substantial number of college students. The objective of this study was to characterize how colleges use their websites to educate about and promote health. This study was a cross-sectional analysis of websites from a nationally representative sample of 426 US colleges. Reviewers abstracted information about Web-based health resources from college websites, namely health information, Web links to outside health resources, and interactive Web-based health programs. Nearly 60% of US colleges provided health resources on their websites, 49% provided health information, 48% provided links to outside resources, and 28% provided interactive Web-based health programs. The most common topics of Web-based health resources were mental health and general health. We found widespread presence of Web-based health resources available from various delivery modes and covering a range of health topics. Although further research in this new modality is warranted, Web-based health resources hold promise for reaching more US college students.

  7. Evaluation of two-fold fully conditional specification multiple imputation for longitudinal electronic health record data

    PubMed Central

    Welch, Catherine A; Petersen, Irene; Bartlett, Jonathan W; White, Ian R; Marston, Louise; Morris, Richard W; Nazareth, Irwin; Walters, Kate; Carpenter, James

    2014-01-01

    Most implementations of multiple imputation (MI) of missing data are designed for simple rectangular data structures ignoring temporal ordering of data. Therefore, when applying MI to longitudinal data with intermittent patterns of missing data, some alternative strategies must be considered. One approach is to divide data into time blocks and implement MI independently at each block. An alternative approach is to include all time blocks in the same MI model. With increasing numbers of time blocks, this approach is likely to break down because of co-linearity and over-fitting. The new two-fold fully conditional specification (FCS) MI algorithm addresses these issues, by only conditioning on measurements, which are local in time. We describe and report the results of a novel simulation study to critically evaluate the two-fold FCS algorithm and its suitability for imputation of longitudinal electronic health records. After generating a full data set, approximately 70% of selected continuous and categorical variables were made missing completely at random in each of ten time blocks. Subsequently, we applied a simple time-to-event model. We compared efficiency of estimated coefficients from a complete records analysis, MI of data in the baseline time block and the two-fold FCS algorithm. The results show that the two-fold FCS algorithm maximises the use of data available, with the gain relative to baseline MI depending on the strength of correlations within and between variables. Using this approach also increases plausibility of the missing at random assumption by using repeated measures over time of variables whose baseline values may be missing. PMID:24782349

  8. Empirical Likelihood in Nonignorable Covariate-Missing Data Problems.

    PubMed

    Xie, Yanmei; Zhang, Biao

    2017-04-20

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

  9. Dark Matter Particle Spectroscopy at the LHC: Generalizing M(T2) to Asymmetric Event Topologies

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Konar, Partha; /Florida U.; Kong, Kyoungchul

    2012-04-03

    We consider SUSY-like missing energy events at hadron colliders and critically examine the common assumption that the missing energy is the result of two identical missing particles. In order to experimentally test this hypothesis, we generalize the subsystem M{sub T2} variable to the case of asymmetric event topologies, where the two SUSY decay chains terminate in different 'children' particles. In this more general approach, the endpoint M{sub T2(max)} of the M{sub T2} distribution now gives the mass {tilde M}p({tilde M}{sub c}{sup (a)}, {tilde M}{sub c}{sup (b)}) of the parent particles as a function of two input children masses {tilde M}{submore » c}{sup (a)} and {tilde M}{sub c}{sup (b)}. We propose two methods for an independent determination of the individual children masses M{sub c}{sup (a)} and M{sub c}{sup (b)}. First, in the presence of upstream transverse momentum PUTM the corresponding function {tilde M}p({tilde M}{sub c}{sup (a)}, {tilde M}{sub c}{sup (b)}, P{sub UTM}) is independent of P{sub UTM} at precisely the right values of the children masses. Second, the previously discussed MT2 'kink' is now generalized to a 'ridge' on the 2-dimensional surface {tilde M}p({tilde M}{sub c}{sup (a)}, {tilde M}{sub c}{sup (b)}). As we show in several examples, quite often there is a special point along that ridge which marks the true values of the children masses. Our results allow collider experiments to probe a multi-component dark matter sector directly and without any theoretical prejudice.« less

  10. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zhang, H; Kong, V; Jin, J

    Purpose: A synchronized moving grid (SMOG) has been proposed to reduce scatter and lag artifacts in cone beam computed tomography (CBCT). However, information is missing in each projection because certain areas are blocked by the grid. A previous solution to this issue is acquiring 2 complimentary projections at each position, which increases scanning time. This study reports our first Result using an inter-projection sensor fusion (IPSF) method to estimate missing projection in our prototype SMOG-based CBCT system. Methods: An in-house SMOG assembling with a 1:1 grid of 3 mm gap has been installed in a CBCT benchtop. The grid movesmore » back and forth in a 3-mm amplitude and up-to 20-Hz frequency. A control program in LabView synchronizes the grid motion with the platform rotation and x-ray firing so that the grid patterns for any two neighboring projections are complimentary. A Catphan was scanned with 360 projections. After scatter correction, the IPSF algorithm was applied to estimate missing signal for each projection using the information from the 2 neighboring projections. Feldkamp-Davis-Kress (FDK) algorithm was applied to reconstruct CBCT images. The CBCTs were compared to those reconstructed using normal projections without applying the SMOG system. Results: The SMOG-IPSF method may reduce image dose by half due to the blocked radiation by the grid. The method almost completely removed scatter related artifacts, such as the cupping artifacts. The evaluation of line pair patterns in the CatPhan suggested that the spatial resolution degradation was minimal. Conclusion: The SMOG-IPSF is promising in reducing scatter artifacts and improving image quality while reducing radiation dose.« less

  11. "Miss! I'm Done!" Finishing Craft Assignments as a Situated Activity System in Preschool

    ERIC Educational Resources Information Center

    Deunk, Marjolein; Berenst, Jan; de Glopper, Kees

    2010-01-01

    We describe the Situated Activity System of finishing craft assignments in preschool: the specific, routinized way that child and teacher jointly close the child's craft assignment, employing a specific discourse pattern. We analyzed the interactions of 14 Dutch children between 2.1 and 3.10 years old while they were finishing their craft…

  12. Unsustainable Development: The Missing Discussion about Education at Rio+20

    ERIC Educational Resources Information Center

    Anderson, Allison

    2012-01-01

    The past 20 years have seen an accelerated process of globalization that has impacted countries around the world. However, not all have benefited equally and many have benefited little or not at all from this process. A global economy based on current patterns of consumption and production is placing heavy stresses on many ecosystems and climate…

  13. A Home in the World? Remarks on India and the Future

    DTIC Science & Technology

    2001-05-01

    their loyalties shift. If you ask an Indian working in America what he or she misses about India, the instant reponse is "Family," not corruption...experts, for whom the past is the pattern of the future. Then, in Burma, with a chopstick load of noodles halfway to my snout, the light finally

  14. Academic Performance in the Context of a "Three Excused Absences" Psychiatry Clerkship Policy

    ERIC Educational Resources Information Center

    Schillerstrom, Jason E.; Lutz, Mary

    2013-01-01

    Objective: In order to better manage medical student absences during the psychiatry clerkship, a policy allowing students to miss up to 3 days without penalty was developed. The purpose of this study was to describe absence patterns and compare academic performance between students with and without absences. Method: Authors reviewed the academic…

  15. A Hierarchical and Contextual Model for Learning and Recognizing Highly Variant Visual Categories

    DTIC Science & Technology

    2010-01-01

    neighboring pattern primitives, to create our model. We also present a minimax entropy framework for automatically learning which contextual constraints are...Grammars . . . . . . . . . . . . . . . . . . 19 3.2 Markov Random Fields . . . . . . . . . . . . . . . . . . . . . . . . 23 3.3 Creating a Contextual...Compositional Boosting. . . . . 119 7.8 Top-down hallucinations of missing objects. . . . . . . . . . . . . . . 121 7.9 The bottom-up to top-down

  16. Applications of artificial intelligence systems in the analysis of epidemiological data.

    PubMed

    Flouris, Andreas D; Duffy, Jack

    2006-01-01

    A brief review of the germane literature suggests that the use of artificial intelligence (AI) statistical algorithms in epidemiology has been limited. We discuss the advantages and disadvantages of using AI systems in large-scale sets of epidemiological data to extract inherent, formerly unidentified, and potentially valuable patterns that human-driven deductive models may miss.

  17. The relevance of error analysis in graphical symbols evaluation.

    PubMed

    Piamonte, D P

    1999-01-01

    In an increasing number of modern tools and devices, small graphical symbols appear simultaneously in sets as parts of the human-machine interfaces. The presence of each symbol can influence the other's recognizability and correct association to its intended referents. Thus, aside from correct associations, it is equally important to perform certain error analysis of the wrong answers, misses, confusions, and even lack of answers. This research aimed to show how such error analyses could be valuable in evaluating graphical symbols especially across potentially different user groups. The study tested 3 sets of icons representing 7 videophone functions. The methods involved parameters such as hits, confusions, missing values, and misses. The association tests showed similar hit rates of most symbols across the majority of the participant groups. However, exploring the error patterns helped detect differences in the graphical symbols' performances between participant groups, which otherwise seemed to have similar levels of recognition. These are very valuable not only in determining the symbols to be retained, replaced or re-designed, but also in formulating instructions and other aids in learning to use new products faster and more satisfactorily.

  18. Kriging in the Shadows: Geostatistical Interpolation for Remote Sensing

    NASA Technical Reports Server (NTRS)

    Rossi, Richard E.; Dungan, Jennifer L.; Beck, Louisa R.

    1994-01-01

    It is often useful to estimate obscured or missing remotely sensed data. Traditional interpolation methods, such as nearest-neighbor or bilinear resampling, do not take full advantage of the spatial information in the image. An alternative method, a geostatistical technique known as indicator kriging, is described and demonstrated using a Landsat Thematic Mapper image in southern Chiapas, Mexico. The image was first classified into pasture and nonpasture land cover. For each pixel that was obscured by cloud or cloud shadow, the probability that it was pasture was assigned by the algorithm. An exponential omnidirectional variogram model was used to characterize the spatial continuity of the image for use in the kriging algorithm. Assuming a cutoff probability level of 50%, the error was shown to be 17% with no obvious spatial bias but with some tendency to categorize nonpasture as pasture (overestimation). While this is a promising result, the method's practical application in other missing data problems for remotely sensed images will depend on the amount and spatial pattern of the unobscured pixels and missing pixels and the success of the spatial continuity model used.

  19. Genetic epidemiology of tooth agenesis in Japan: a population- and family-based study.

    PubMed

    Machida, J; Nishiyama, T; Kishino, H; Yamaguchi, S; Kimura, M; Shibata, A; Tatematsu, T; Kamamoto, M; Yamamoto, K; Makino, S; Miyachi, H; Shimozato, K; Tokita, Y

    2015-08-01

    Tooth agenesis is one of the most common congenital anomalies in humans. However, the etiology of tooth agenesis remains largely unclear, as well as evidence base useful for genetic counseling. Therefore, we estimated the prevalence and sibling recurrence risk, and investigated agenetic patterns systematically. Tooth agenesis was classified into two subtypes: hypodontia (one to five missing teeth) and oligodontia (six or more missing teeth). The prevalence of these two subtypes were 6.8% [95% confidence interval (CI): 6.1-7.7%] and 0.1% (95% CI: 0.04-0.3%), respectively, and sibling recurrence risk of these were 24.5% (95% CI: 13.8-38.3%) and 43.8% (95% CI: 26.4-62.3%), respectively. This result suggests that the severe phenotype, oligodontia, might be mostly transmitted in a dominant fashion. Using a simple statistical modeling approach, our data were found to be consistent with a bilateral symmetry model, meaning that there was equal probability of missing teeth from the right and left sides. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  20. Sleepiness and Motor Vehicle Crashes in a Representative Sample of Portuguese Drivers: The Importance of Epidemiological Representative Surveys.

    PubMed

    Gonçalves, M; Peralta, A R; Monteiro Ferreira, J; Guilleminault, Christian

    2015-01-01

    Sleepiness is considered to be a leading cause of crashes. Despite the huge amount of information collected in questionnaire studies, only some are based on representative samples of the population. Specifics of the populations studied hinder the generalization of these previous findings. For the Portuguese population, data from sleep-related car crashes/near misses and sleepiness while driving are missing. The objective of this study is to determine the prevalence of near-miss and nonfatal motor vehicle crashes related to sleepiness in a representative sample of Portuguese drivers. Structured phone interviews regarding sleepiness and sleep-related crashes and near misses, driving habits, demographic data, and sleep quality were conducted using the Pittsburgh Sleep Quality Index and sleep apnea risk using the Berlin questionnaire. A multivariate regression analysis was used to determine the associations with sleepy driving (feeling sleepy or falling asleep while driving) and sleep-related near misses and crashes. Nine hundred subjects, representing the Portuguese population of drivers, were included; 3.1% acknowledged falling asleep while driving during the previous year and 0.67% recalled sleepiness-related crashes. Higher education, driving more than 15,000 km/year, driving more frequently between 12:00 a.m. and 6 a.m., fewer years of having a driver's license, less total sleep time per night, and higher scores on the Epworth Sleepiness Scale (ESS) were all independently associated with sleepy driving. Sleepiness-related crashes and near misses were associated only with falling asleep at the wheel in the previous year. Sleep-related crashes occurred more frequently in drivers who had also had sleep-related near misses. Portugal has lower self-reported sleepiness at the wheel and sleep-related near misses than most other countries where epidemiological data are available. Different population characteristics and cultural, social, and road safety specificities may be involved in these discrepancies. Despite this, Portuguese drivers report sleep-related crashes in frequencies similar to those of drivers in other countries.

  1. Salix polaris growth responses to active layer detachment and solifluction processes in High Arctic.

    NASA Astrophysics Data System (ADS)

    Siekacz, Liliana

    2015-04-01

    The work is dedicated to demonstrate the potential of Salix polaris grow properties in the dendrogemorphologic image, analyzing periglacially induced slope processes in the high Arctic.. Observed anatomical and morphological plants responses to solifluction and active layer detachment processes are presented qualitatively and quantitatively as a summary of presented features frequency. The results are discussed against the background of the other research results in this field. The investigations was performed in Ebba valley, in the vicinity of Petunia Bay, northernmost part of Billefjorden in central Spitsbergen (Svalbard). Environmental conditions are characterized by annual precipitation sum lower than 200 mm (Hagen et al.,1993) and average summer temperature of about 5°C, with maximum daily temperatures rarely exceeding 10°C (Rachlewicz, 2009). Collected shrub material was prepared according to the methods presented by Schweingruber and Poschlod (2005). Thin (approx. 15-20μm) sections of the whole cross-section were prepared with a sledge microtome, stained with Safranine and Astra blue and finally permanently fixed on microslides with Canada balsam and dried. Snapshots were taken partially for each cross-section with digital camera (ColorView III, Olympus) connected to a microscope (Olympus BX41) and merged into one, high resolution image. After all, ring widths were measured in 3-4 radii in every single cross-section using ImageJ software. Analyzed plants revealed extremely harsh environmental conditions of their growth. Buchwał et al. (2013) provided quantitative data concerning missing rings and partially missing rings in shrubs growing on Ebba valley floor. Mean ring width at the level of 79μm represents one of the smallest values of yearly growth ever noted. The share of missing rings and partially missing rings was 11,2% and 13,6% respectively. Plants growing on Ebba valley slope indicate almost twice smaller values of ring width (41μm), and higher participation of missing and partially missing rings. Share of missing rings in shrubs growing within an active layer detachment on the valley slope reached 16,22% and 15,36%. Even higher variation is observed in partially missing rings which account for 31,07% within detachment and 23,39% on surrounding slope. Those values are more than twice higher comparing to the valley floor. There is also noticeable difference between detachment and surrounding slope indicating that wedging rings are an effect of mechanical stress that is higher within the detachment. Comparing growth patterns in aboveground and belowground plant parts different growth allocation is noticed. Years of detachment event growth rings were present only in aboveground parts. It is supposed that mechanical stress delays the onset of the growing season similarly to low temperatures (Buchwał et al., 2013), resulting in not enough time to fully allocate resources for growth in the belowground parts. Growth pattern is extremely irregular, indicating that the slope is in constant movement, which disrupts growth conditions. Analyzed shrubs showed two possible event years: 2006 and 2008, with the highest participation of missing and partially missing rings. Air and ground temperature data were also analyzed and confirmed that active layer detachment happened in 2006. REFERENCES Buchwał A, Rachlewicz G, Fonti P, Cherubini P, Gärtner H, (2013) Temperature modulates intra-plant growth of Salix Polaris from a high Arctic site (Svalbard). Polar Biol 36:1305-1318. Hagen J O, Liestøl O, Roland E, Jørgensen T, (1993) Glacier atlas of Svalbard and Jan Mayen. Norsk Polarinstitutt Meddelelser 129: 160. Rachlewicz G, (2009) Contemporary sediment fluxes and relief changes in high Arctic glacierized valley systems (Billefjorden, Central Spitsbergen). Wyd. Nauk. UAM Poznań, seria Geografia 87:204. Schweingruber FH, Poschlod P, (2005) Growth rings in herbs and shrubs: life span, age determination and stem anatomy. For Snow Landsc Res 79:195-415

  2. Missing Alzheimer's Disease Patient Alert Program Reauthorization of 2009

    THOMAS, 111th Congress

    Rep. Waters, Maxine [D-CA-35

    2009-02-04

    Senate - 06/25/2010 Placed on Senate Legislative Calendar under General Orders. Calendar No. 444. (All Actions) Tracker: This bill has the status Passed HouseHere are the steps for Status of Legislation:

  3. A Child Is Missing Alert and Recovery Center Act

    THOMAS, 111th Congress

    Rep. Klein, Ron [D-FL-22

    2009-04-02

    Senate - 07/13/2010 Placed on Senate Legislative Calendar under General Orders. Calendar No. 458. (All Actions) Tracker: This bill has the status Passed HouseHere are the steps for Status of Legislation:

  4. Forbidden patterns in financial time series

    NASA Astrophysics Data System (ADS)

    Zanin, Massimiliano

    2008-03-01

    The existence of forbidden patterns, i.e., certain missing sequences in a given time series, is a recently proposed instrument of potential application in the study of time series. Forbidden patterns are related to the permutation entropy, which has the basic properties of classic chaos indicators, such as Lyapunov exponent or Kolmogorov entropy, thus allowing to separate deterministic (usually chaotic) from random series; however, it requires fewer values of the series to be calculated, and it is suitable for using with small datasets. In this paper, the appearance of forbidden patterns is studied in different economical indicators such as stock indices (Dow Jones Industrial Average and Nasdaq Composite), NYSE stocks (IBM and Boeing), and others (ten year Bond interest rate), to find evidence of deterministic behavior in their evolutions. Moreover, the rate of appearance of the forbidden patterns is calculated, and some considerations about the underlying dynamics are suggested.

  5. Sequential pattern formation governed by signaling gradients

    NASA Astrophysics Data System (ADS)

    Jörg, David J.; Oates, Andrew C.; Jülicher, Frank

    2016-10-01

    Rhythmic and sequential segmentation of the embryonic body plan is a vital developmental patterning process in all vertebrate species. However, a theoretical framework capturing the emergence of dynamic patterns of gene expression from the interplay of cell oscillations with tissue elongation and shortening and with signaling gradients, is still missing. Here we show that a set of coupled genetic oscillators in an elongating tissue that is regulated by diffusing and advected signaling molecules can account for segmentation as a self-organized patterning process. This system can form a finite number of segments and the dynamics of segmentation and the total number of segments formed depend strongly on kinetic parameters describing tissue elongation and signaling molecules. The model accounts for existing experimental perturbations to signaling gradients, and makes testable predictions about novel perturbations. The variety of different patterns formed in our model can account for the variability of segmentation between different animal species.

  6. Subjective Prior Distributions for Modeling Longitudinal Continuous Outcomes with Non-Ignorable Dropout

    PubMed Central

    Paddock, Susan M.; Ebener, Patricia

    2010-01-01

    Substance abuse treatment research is complicated by the pervasive problem of non-ignorable missing data – i.e., the occurrence of the missing data is related to the unobserved outcomes. Missing data frequently arise due to early client departure from treatment. Pattern-mixture models (PMMs) are often employed in such situations to jointly model the outcome and the missing data mechanism. PMMs require non-testable assumptions to identify model parameters. Several approaches to parameter identification have therefore been explored for longitudinal modeling of continuous outcomes, and informative priors have been developed in other contexts. In this paper, we describe an expert interview conducted with five substance abuse treatment clinical experts who have familiarity with the Therapeutic Community modality of substance abuse treatment and with treatment process scores collected using the Dimensions of Change Instrument. The goal of the interviews was to obtain expert opinion about the rate of change in continuous client-level treatment process scores for clients who leave before completing two assessments and whose rate of change (slope) in treatment process scores is unidentified by the data. We find that the experts’ opinions differed dramatically from widely-utilized assumptions used to identify parameters in the PMM. Further, subjective prior assessment allows one to properly address the uncertainty inherent in the subjective decisions required to identify parameters in the PMM and to measure their effect on conclusions drawn from the analysis. PMID:19012279

  7. Adaptive detection of missed text areas in OCR outputs: application to the automatic assessment of OCR quality in mass digitization projects

    NASA Astrophysics Data System (ADS)

    Ben Salah, Ahmed; Ragot, Nicolas; Paquet, Thierry

    2013-01-01

    The French National Library (BnF*) has launched many mass digitization projects in order to give access to its collection. The indexation of digital documents on Gallica (digital library of the BnF) is done through their textual content obtained thanks to service providers that use Optical Character Recognition softwares (OCR). OCR softwares have become increasingly complex systems composed of several subsystems dedicated to the analysis and the recognition of the elements in a page. However, the reliability of these systems is always an issue at stake. Indeed, in some cases, we can find errors in OCR outputs that occur because of an accumulation of several errors at different levels in the OCR process. One of the frequent errors in OCR outputs is the missed text components. The presence of such errors may lead to severe defects in digital libraries. In this paper, we investigate the detection of missed text components to control the OCR results from the collections of the French National Library. Our verification approach uses local information inside the pages based on Radon transform descriptors and Local Binary Patterns descriptors (LBP) coupled with OCR results to control their consistency. The experimental results show that our method detects 84.15% of the missed textual components, by comparing the OCR ALTO files outputs (produced by the service providers) to the images of the document.

  8. Audio-Enhanced Tablet Computers to Assess Children's Food Frequency From Migrant Farmworker Mothers.

    PubMed

    Kilanowski, Jill F; Trapl, Erika S; Kofron, Ryan M

    2013-06-01

    This study sought to improve data collection in children's food frequency surveys for non-English speaking immigrant/migrant farmworker mothers using audio-enhanced tablet computers (ATCs). We hypothesized that by using technological adaptations, we would be able to improve data capture and therefore reduce lost surveys. This Food Frequency Questionnaire (FFQ), a paper-based dietary assessment tool, was adapted for ATCs and assessed consumption of 66 food items asking 3 questions for each food item: frequency, quantity of consumption, and serving size. The tablet-based survey was audio enhanced with each question "read" to participants, accompanied by food item images, together with an embedded short instructional video. Results indicated that respondents were able to complete the 198 questions from the 66 food item FFQ on ATCs in approximately 23 minutes. Compared with paper-based FFQs, ATC-based FFQs had less missing data. Despite overall reductions in missing data by use of ATCs, respondents still appeared to have difficulty with question 2 of the FFQ. Ability to score the FFQ was dependent on what sections missing data were located. Unlike the paper-based FFQs, no ATC-based FFQs were unscored due to amount or location of missing data. An ATC-based FFQ was feasible and increased ability to score this survey on children's food patterns from migrant farmworker mothers. This adapted technology may serve as an exemplar for other non-English speaking immigrant populations.

  9. Spatial distribution of emergency obstetric and newborn care services in Ghana: Using the evidence to plan interventions.

    PubMed

    Bosomprah, Samuel; Tatem, Andrew J; Dotse-Gborgbortsi, Winfred; Aboagye, Patrick; Matthews, Zoe

    2016-01-01

    To provide clear policy directions for gaps in the provision of signal function services and sub-regions requiring priority attention using data from the 2010 Ghana Emergency Obstetric and Newborn Care (EmONC) survey. Using 2010 survey data, the fraction of facilities with only one or two signal functions missing was calculated for each facility type and EmONC designation. Thematic maps were used to provide insight into inequities in service provision. Of 1159 maternity facilities, 89 provided all the necessary basic or comprehensive EmONC signal functions 3months prior to the 2010 survey. Only 21% of facility-based births were in fully functioning EmONC facilities, but an additional 30% occurred in facilities missing one or two basic signal functions-most often assisted vaginal delivery and removal of retained products. Tackling these missing signal functions would extend births taking place in fully functioning facilities to over 50%. Subnational analyses based on estimated total pregnancies in each district revealed a pattern of inequity in service provision across the country. Upgrading facilities missing only one or two signal functions will allow Ghana to meet international standards for availability of EmONC services. Reducing maternal deaths will require high national priority given to addressing inequities in the distribution of EmONC services. Copyright © 2015 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

  10. Everything You Always Wanted to Know about Judgment, but Were Afraid to Ask!

    ERIC Educational Resources Information Center

    Priest, Simon

    1990-01-01

    Outdoor leaders with sound judgment can gather many specific experiences, induce them into a collection of general concepts, store these as memory maps in the mind, later recall the general concepts as needed, and deduce a specific prediction from them. Proposes that evaluative reflection after a judgment is made is the component missing from most…

  11. Institutional Pedagogy and Semiosis: Investigating the Missing Link between Peirce's Semiotics and Effective Semiotics

    ERIC Educational Resources Information Center

    Pesce, Sebastien

    2011-01-01

    My aim in this paper is to show the relevance of an "effective semiotics"; that is, a field study based upon Peirce's semiotics. The general context of this investigation is educational semiotics rather than semiotics of teaching: I am concerned with a general approach of educational processes, not with skills and curricula. My paper is…

  12. Improving the Teaching/Learning Process in General Chemistry: Report on the 1997 Stony Brook General Chemistry Teaching Workshop.

    ERIC Educational Resources Information Center

    Hanson, David; Wolfskill, Troy

    1998-01-01

    The primary focus of this participant-centered workshop was to introduce the student-centered classroom. Describes the model for the conference and issues addressed which include process as the missing element in the curriculum; peer-led learning teams; integrating chemistry, mathematics, and physics; writing as a learning tool in chemistry;…

  13. Multiple Imputation based Clustering Validation (MIV) for Big Longitudinal Trial Data with Missing Values in eHealth.

    PubMed

    Zhang, Zhaoyang; Fang, Hua; Wang, Honggang

    2016-06-01

    Web-delivered trials are an important component in eHealth services. These trials, mostly behavior-based, generate big heterogeneous data that are longitudinal, high dimensional with missing values. Unsupervised learning methods have been widely applied in this area, however, validating the optimal number of clusters has been challenging. Built upon our multiple imputation (MI) based fuzzy clustering, MIfuzzy, we proposed a new multiple imputation based validation (MIV) framework and corresponding MIV algorithms for clustering big longitudinal eHealth data with missing values, more generally for fuzzy-logic based clustering methods. Specifically, we detect the optimal number of clusters by auto-searching and -synthesizing a suite of MI-based validation methods and indices, including conventional (bootstrap or cross-validation based) and emerging (modularity-based) validation indices for general clustering methods as well as the specific one (Xie and Beni) for fuzzy clustering. The MIV performance was demonstrated on a big longitudinal dataset from a real web-delivered trial and using simulation. The results indicate MI-based Xie and Beni index for fuzzy-clustering are more appropriate for detecting the optimal number of clusters for such complex data. The MIV concept and algorithms could be easily adapted to different types of clustering that could process big incomplete longitudinal trial data in eHealth services.

  14. Multiple Imputation based Clustering Validation (MIV) for Big Longitudinal Trial Data with Missing Values in eHealth

    PubMed Central

    Zhang, Zhaoyang; Wang, Honggang

    2016-01-01

    Web-delivered trials are an important component in eHealth services. These trials, mostly behavior-based, generate big heterogeneous data that are longitudinal, high dimensional with missing values. Unsupervised learning methods have been widely applied in this area, however, validating the optimal number of clusters has been challenging. Built upon our multiple imputation (MI) based fuzzy clustering, MIfuzzy, we proposed a new multiple imputation based validation (MIV) framework and corresponding MIV algorithms for clustering big longitudinal eHealth data with missing values, more generally for fuzzy-logic based clustering methods. Specifically, we detect the optimal number of clusters by auto-searching and -synthesizing a suite of MI-based validation methods and indices, including conventional (bootstrap or cross-validation based) and emerging (modularity-based) validation indices for general clustering methods as well as the specific one (Xie and Beni) for fuzzy clustering. The MIV performance was demonstrated on a big longitudinal dataset from a real web-delivered trial and using simulation. The results indicate MI-based Xie and Beni index for fuzzy-clustering is more appropriate for detecting the optimal number of clusters for such complex data. The MIV concept and algorithms could be easily adapted to different types of clustering that could process big incomplete longitudinal trial data in eHealth services. PMID:27126063

  15. Search for supersymmetry in events with photons and missing transverse energy in pp collisions at 13 TeV

    NASA Astrophysics Data System (ADS)

    Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Asilar, E.; Bergauer, T.; Brandstetter, J.; Brondolin, E.; Dragicevic, M.; Erö, J.; Flechl, M.; Friedl, M.; Frühwirth, R.; Ghete, V. M.; Hartl, C.; Hörmann, N.; Hrubec, J.; Jeitler, M.; König, A.; Krätschmer, I.; Liko, D.; Matsushita, T.; Mikulec, I.; Rabady, D.; Rad, N.; Rahbaran, B.; Rohringer, H.; Schieck, J.; Strauss, J.; Waltenberger, W.; Wulz, C.-E.; Mossolov, V.; Shumeiko, N.; Suarez Gonzalez, J.; Alderweireldt, S.; De Wolf, E. A.; Janssen, X.; Lauwers, J.; Van De Klundert, M.; Van Haevermaet, H.; Van Mechelen, P.; Van Remortel, N.; Van Spilbeeck, A.; Abu Zeid, S.; Blekman, F.; D'Hondt, J.; Daci, N.; De Bruyn, I.; Deroover, K.; Heracleous, N.; Lowette, S.; Moortgat, S.; Moreels, L.; Olbrechts, A.; Python, Q.; Tavernier, S.; Van Doninck, W.; Van Mulders, P.; Van Parijs, I.; Brun, H.; Caillol, C.; Clerbaux, B.; De Lentdecker, G.; Delannoy, H.; Fasanella, G.; Favart, L.; Goldouzian, R.; Grebenyuk, A.; Karapostoli, G.; Lenzi, T.; Léonard, A.; Luetic, J.; Maerschalk, T.; Marinov, A.; Randle-conde, A.; Seva, T.; Vander Velde, C.; Vanlaer, P.; Yonamine, R.; Zenoni, F.; Zhang, F.; Cimmino, A.; Cornelis, T.; Dobur, D.; Fagot, A.; Garcia, G.; Gul, M.; Poyraz, D.; Salva, S.; Schöfbeck, R.; Sharma, A.; Tytgat, M.; Van Driessche, W.; Yazgan, E.; Zaganidis, N.; Bakhshiansohi, H.; Beluffi, C.; Bondu, O.; Brochet, S.; Bruno, G.; Caudron, A.; De Visscher, S.; Delaere, C.; Delcourt, M.; Francois, B.; Giammanco, A.; Jafari, A.; Jez, P.; Komm, M.; Lemaitre, V.; Magitteri, A.; Mertens, A.; Musich, M.; Nuttens, C.; Piotrzkowski, K.; Quertenmont, L.; Selvaggi, M.; Vidal Marono, M.; Wertz, S.; Beliy, N.; Aldá Júnior, W. L.; Alves, F. L.; Alves, G. A.; Brito, L.; Hensel, C.; Moraes, A.; Pol, M. E.; Rebello Teles, P.; Belchior Batista Das Chagas, E.; Carvalho, W.; Chinellato, J.; Custódio, A.; Da Costa, E. M.; Da Silveira, G. G.; De Jesus Damiao, D.; De Oliveira Martins, C.; Fonseca De Souza, S.; Huertas Guativa, L. M.; Malbouisson, H.; Matos Figueiredo, D.; Mora Herrera, C.; Mundim, L.; Nogima, H.; Prado Da Silva, W. L.; Santoro, A.; Sznajder, A.; Tonelli Manganote, E. J.; Vilela Pereira, A.; Ahuja, S.; Bernardes, C. A.; Dogra, S.; Fernandez Perez Tomei, T. R.; Gregores, E. M.; Mercadante, P. G.; Moon, C. S.; Novaes, S. F.; Padula, Sandra S.; Romero Abad, D.; Ruiz Vargas, J. C.; Aleksandrov, A.; Hadjiiska, R.; Iaydjiev, P.; Rodozov, M.; Stoykova, S.; Sultanov, G.; Vutova, M.; Dimitrov, A.; Glushkov, I.; Litov, L.; Pavlov, B.; Petkov, P.; Fang, W.; Ahmad, M.; Bian, J. G.; Chen, G. M.; Chen, H. S.; Chen, M.; Chen, Y.; Cheng, T.; Jiang, C. H.; Leggat, D.; Liu, Z.; Romeo, F.; Shaheen, S. M.; Spiezia, A.; Tao, J.; Wang, C.; Wang, Z.; Zhang, H.; Zhao, J.; Ban, Y.; Chen, G.; Li, Q.; Liu, S.; Mao, Y.; Qian, S. J.; Wang, D.; Xu, Z.; Avila, C.; Cabrera, A.; Chaparro Sierra, L. F.; Florez, C.; Gomez, J. P.; González Hernández, C. F.; Ruiz Alvarez, J. D.; Sanabria, J. C.; Godinovic, N.; Lelas, D.; Puljak, I.; Ribeiro Cipriano, P. M.; Sculac, T.; Antunovic, Z.; Kovac, M.; Brigljevic, V.; Ferencek, D.; Kadija, K.; Micanovic, S.; Sudic, L.; Susa, T.; Attikis, A.; Mavromanolakis, G.; Mousa, J.; Nicolaou, C.; Ptochos, F.; Razis, P. A.; Rykaczewski, H.; Finger, M.; Finger, M.; Carrera Jarrin, E.; Abdelalim, A. A.; Mohammed, Y.; Salama, E.; Calpas, B.; Kadastik, M.; Murumaa, M.; Perrini, L.; Raidal, M.; Tiko, A.; Veelken, C.; Eerola, P.; Pekkanen, J.; Voutilainen, M.; Härkönen, J.; Karimäki, V.; Kinnunen, R.; Lampén, T.; Lassila-Perini, K.; Lehti, S.; Lindén, T.; Luukka, P.; Tuominiemi, J.; Tuovinen, E.; Wendland, L.; Talvitie, J.; Tuuva, T.; Besancon, M.; Couderc, F.; Dejardin, M.; Denegri, D.; Fabbro, B.; Faure, J. L.; Favaro, C.; Ferri, F.; Ganjour, S.; Ghosh, S.; Givernaud, A.; Gras, P.; Hamel de Monchenault, G.; Jarry, P.; Kucher, I.; Locci, E.; Machet, M.; Malcles, J.; Rander, J.; Rosowsky, A.; Titov, M.; Zghiche, A.; Abdulsalam, A.; Antropov, I.; Baffioni, S.; Beaudette, F.; Busson, P.; Cadamuro, L.; Chapon, E.; Charlot, C.; Davignon, O.; Granier de Cassagnac, R.; Jo, M.; Lisniak, S.; Miné, P.; Nguyen, M.; Ochando, C.; Ortona, G.; Paganini, P.; Pigard, P.; Regnard, S.; Salerno, R.; Sirois, Y.; Strebler, T.; Yilmaz, Y.; Zabi, A.; Agram, J.-L.; Andrea, J.; Aubin, A.; Bloch, D.; Brom, J.-M.; Buttignol, M.; Chabert, E. C.; Chanon, N.; Collard, C.; Conte, E.; Coubez, X.; Fontaine, J.-C.; Gelé, D.; Goerlach, U.; Le Bihan, A.-C.; Skovpen, K.; Van Hove, P.; Gadrat, S.; Beauceron, S.; Bernet, C.; Boudoul, G.; Bouvier, E.; Carrillo Montoya, C. A.; Chierici, R.; Contardo, D.; Courbon, B.; Depasse, P.; El Mamouni, H.; Fan, J.; Fay, J.; Gascon, S.; Gouzevitch, M.; Grenier, G.; Ille, B.; Lagarde, F.; Laktineh, I. B.; Lethuillier, M.; Mirabito, L.; Pequegnot, A. L.; Perries, S.; Popov, A.; Sabes, D.; Sordini, V.; Vander Donckt, M.; Verdier, P.; Viret, S.; Khvedelidze, A.; Tsamalaidze, Z.; Autermann, C.; Beranek, S.; Feld, L.; Heister, A.; Kiesel, M. 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J.; Ulrich, R.; Wagner-Kuhr, J.; Wayand, S.; Weber, M.; Weiler, T.; Williamson, S.; Wöhrmann, C.; Wolf, R.; Anagnostou, G.; Daskalakis, G.; Geralis, T.; Giakoumopoulou, V. A.; Kyriakis, A.; Loukas, D.; Topsis-Giotis, I.; Kesisoglou, S.; Panagiotou, A.; Saoulidou, N.; Tziaferi, E.; Evangelou, I.; Flouris, G.; Foudas, C.; Kokkas, P.; Loukas, N.; Manthos, N.; Papadopoulos, I.; Paradas, E.; Filipovic, N.; Bencze, G.; Hajdu, C.; Hidas, P.; Horvath, D.; Sikler, F.; Veszpremi, V.; Vesztergombi, G.; Zsigmond, A. J.; Beni, N.; Czellar, S.; Karancsi, J.; Makovec, A.; Molnar, J.; Szillasi, Z.; Bartók, M.; Raics, P.; Trocsanyi, Z. L.; Ujvari, B.; Bahinipati, S.; Choudhury, S.; Mal, P.; Mandal, K.; Nayak, A.; Sahoo, D. K.; Sahoo, N.; Swain, S. K.; Bansal, S.; Beri, S. B.; Bhatnagar, V.; Chawla, R.; Bhawandeep, U.; Kalsi, A. K.; Kaur, A.; Kaur, M.; Kumar, R.; Kumari, P.; Mehta, A.; Mittal, M.; Singh, J. B.; Walia, G.; Kumar, Ashok; Bhardwaj, A.; Choudhary, B. C.; Garg, R. B.; Keshri, S.; Malhotra, S.; Naimuddin, M.; Nishu, N.; Ranjan, K.; Sharma, R.; Sharma, V.; Bhattacharya, R.; Bhattacharya, S.; Chatterjee, K.; Dey, S.; Dutt, S.; Dutta, S.; Ghosh, S.; Majumdar, N.; Modak, A.; Mondal, K.; Mukhopadhyay, S.; Nandan, S.; Purohit, A.; Roy, A.; Roy, D.; Roy Chowdhury, S.; Sarkar, S.; Sharan, M.; Thakur, S.; Behera, P. K.; Chudasama, R.; Dutta, D.; Jha, V.; Kumar, V.; Mohanty, A. K.; Netrakanti, P. K.; Pant, L. M.; Shukla, P.; Topkar, A.; Aziz, T.; Dugad, S.; Kole, G.; Mahakud, B.; Mitra, S.; Mohanty, G. B.; Parida, B.; Sur, N.; Sutar, B.; Banerjee, S.; Bhowmik, S.; Dewanjee, R. K.; Ganguly, S.; Guchait, M.; Jain, Sa.; Kumar, S.; Maity, M.; Majumder, G.; Mazumdar, K.; Sarkar, T.; Wickramage, N.; Chauhan, S.; Dube, S.; Hegde, V.; Kapoor, A.; Kothekar, K.; Rane, A.; Sharma, S.; Behnamian, H.; Chenarani, S.; Eskandari Tadavani, E.; Etesami, S. M.; Fahim, A.; Khakzad, M.; Mohammadi Najafabadi, M.; Naseri, M.; Paktinat Mehdiabadi, S.; Rezaei Hosseinabadi, F.; Safarzadeh, B.; Zeinali, M.; Felcini, M.; Grunewald, M.; Abbrescia, M.; Calabria, C.; Caputo, C.; Colaleo, A.; Creanza, D.; Cristella, L.; De Filippis, N.; De Palma, M.; Fiore, L.; Iaselli, G.; Maggi, G.; Maggi, M.; Miniello, G.; My, S.; Nuzzo, S.; Pompili, A.; Pugliese, G.; Radogna, R.; Ranieri, A.; Selvaggi, G.; Silvestris, L.; Venditti, R.; Verwilligen, P.; Abbiendi, G.; Battilana, C.; Bonacorsi, D.; Braibant-Giacomelli, S.; Brigliadori, L.; Campanini, R.; Capiluppi, P.; Castro, A.; Cavallo, F. R.; Chhibra, S. S.; Codispoti, G.; Cuffiani, M.; Dallavalle, G. M.; Fabbri, F.; Fanfani, A.; Fasanella, D.; Giacomelli, P.; Grandi, C.; Guiducci, L.; Marcellini, S.; Masetti, G.; Montanari, A.; Navarria, F. L.; Perrotta, A.; Rossi, A. M.; Rovelli, T.; Siroli, G. 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M.; Lanza, G.; Lista, L.; Meola, S.; Paolucci, P.; Sciacca, C.; Thyssen, F.; Azzi, P.; Bacchetta, N.; Benato, L.; Bisello, D.; Boletti, A.; Carlin, R.; Carvalho Antunes De Oliveira, A.; Checchia, P.; Dall'Osso, M.; De Castro Manzano, P.; Dorigo, T.; Dosselli, U.; Gasparini, F.; Gasparini, U.; Gozzelino, A.; Lacaprara, S.; Margoni, M.; Meneguzzo, A. T.; Pazzini, J.; Pozzobon, N.; Ronchese, P.; Simonetto, F.; Torassa, E.; Zanetti, M.; Zotto, P.; Zumerle, G.; Braghieri, A.; Magnani, A.; Montagna, P.; Ratti, S. P.; Re, V.; Riccardi, C.; Salvini, P.; Vai, I.; Vitulo, P.; Alunni Solestizi, L.; Bilei, G. M.; Ciangottini, D.; Fanò, L.; Lariccia, P.; Leonardi, R.; Mantovani, G.; Menichelli, M.; Saha, A.; Santocchia, A.; Androsov, K.; Azzurri, P.; Bagliesi, G.; Bernardini, J.; Boccali, T.; Castaldi, R.; Ciocci, M. A.; Dell'Orso, R.; Donato, S.; Fedi, G.; Giassi, A.; Grippo, M. T.; Ligabue, F.; Lomtadze, T.; Martini, L.; Messineo, A.; Palla, F.; Rizzi, A.; Savoy-Navarro, A.; Spagnolo, P.; Tenchini, R.; Tonelli, G.; Venturi, A.; Verdini, P. G.; Barone, L.; Cavallari, F.; Cipriani, M.; D'imperio, G.; Del Re, D.; Diemoz, M.; Gelli, S.; Longo, E.; Margaroli, F.; Marzocchi, B.; Meridiani, P.; Organtini, G.; Paramatti, R.; Preiato, F.; Rahatlou, S.; Rovelli, C.; Santanastasio, F.; Amapane, N.; Arcidiacono, R.; Argiro, S.; Arneodo, M.; Bartosik, N.; Bellan, R.; Biino, C.; Cartiglia, N.; Cenna, F.; Costa, M.; Covarelli, R.; Degano, A.; Demaria, N.; Finco, L.; Kiani, B.; Mariotti, C.; Maselli, S.; Migliore, E.; Monaco, V.; Monteil, E.; Obertino, M. M.; Pacher, L.; Pastrone, N.; Pelliccioni, M.; Pinna Angioni, G. L.; Ravera, F.; Romero, A.; Ruspa, M.; Sacchi, R.; Shchelina, K.; Sola, V.; Solano, A.; Staiano, A.; Traczyk, P.; Belforte, S.; Casarsa, M.; Cossutti, F.; Della Ricca, G.; Zanetti, A.; Kim, D. H.; Kim, G. N.; Kim, M. S.; Lee, S.; Lee, S. W.; Oh, Y. D.; Sekmen, S.; Son, D. C.; Yang, Y. C.; Lee, A.; Kim, H.; Brochero Cifuentes, J. A.; Kim, T. J.; Cho, S.; Choi, S.; Go, Y.; Gyun, D.; Ha, S.; Hong, B.; Jo, Y.; Kim, Y.; Lee, B.; Lee, K.; Lee, K. S.; Lee, S.; Lim, J.; Park, S. K.; Roh, Y.; Almond, J.; Kim, J.; Lee, H.; Oh, S. B.; Radburn-Smith, B. C.; Seo, S. h.; Yang, U. K.; Yoo, H. D.; Yu, G. B.; Choi, M.; Kim, H.; Kim, J. H.; Lee, J. S. H.; Park, I. C.; Ryu, G.; Ryu, M. S.; Choi, Y.; Goh, J.; Hwang, C.; Lee, J.; Yu, I.; Dudenas, V.; Juodagalvis, A.; Vaitkus, J.; Ahmed, I.; Ibrahim, Z. A.; Komaragiri, J. R.; Md Ali, M. A. B.; Mohamad Idris, F.; Wan Abdullah, W. A. T.; Yusli, M. N.; Zolkapli, Z.; Castilla-Valdez, H.; De La Cruz-Burelo, E.; Heredia-De La Cruz, I.; Hernandez-Almada, A.; Lopez-Fernandez, R.; Magaña Villalba, R.; Mejia Guisao, J.; Sanchez-Hernandez, A.; Carrillo Moreno, S.; Oropeza Barrera, C.; Vazquez Valencia, F.; Carpinteyro, S.; Pedraza, I.; Salazar Ibarguen, H. A.; Uribe Estrada, C.; Morelos Pineda, A.; Krofcheck, D.; Butler, P. H.; Ahmad, A.; Ahmad, M.; Hassan, Q.; Hoorani, H. R.; Khan, W. A.; Saddique, A.; Shah, M. A.; Shoaib, M.; Waqas, M.; Bialkowska, H.; Bluj, M.; Boimska, B.; Frueboes, T.; Górski, M.; Kazana, M.; Nawrocki, K.; Romanowska-Rybinska, K.; Szleper, M.; Zalewski, P.; Bunkowski, K.; Byszuk, A.; Doroba, K.; Kalinowski, A.; Konecki, M.; Krolikowski, J.; Misiura, M.; Olszewski, M.; Walczak, M.; Bargassa, P.; Beirão Da Cruz E Silva, C.; Di Francesco, A.; Faccioli, P.; Ferreira Parracho, P. G.; Gallinaro, M.; Hollar, J.; Leonardo, N.; Lloret Iglesias, L.; Nemallapudi, M. V.; Rodrigues Antunes, J.; Seixas, J.; Toldaiev, O.; Vadruccio, D.; Varela, J.; Vischia, P.; Afanasiev, S.; Alexakhin, V.; Bunin, P.; Gavrilenko, M.; Golutvin, I.; Gorbunov, I.; Karjavin, V.; Lanev, A.; Malakhov, A.; Matveev, V.; Palichik, V.; Perelygin, V.; Savina, M.; Shmatov, S.; Shulha, S.; Skatchkov, N.; Smirnov, V.; Zarubin, A.; Chtchipounov, L.; Golovtsov, V.; Ivanov, Y.; Kim, V.; Kuznetsova, E.; Murzin, V.; Oreshkin, V.; Sulimov, V.; Vorobyev, A.; Andreev, Yu.; Dermenev, A.; Gninenko, S.; Golubev, N.; Karneyeu, A.; Kirsanov, M.; Krasnikov, N.; Pashenkov, A.; Tlisov, D.; Toropin, A.; Epshteyn, V.; Gavrilov, V.; Lychkovskaya, N.; Popov, V.; Pozdnyakov, I.; Safronov, G.; Spiridonov, A.; Toms, M.; Vlasov, E.; Zhokin, A.; Bylinkin, A.; Chistov, R.; Danilov, M.; Rusinov, V.; Andreev, V.; Azarkin, M.; Dremin, I.; Kirakosyan, M.; Leonidov, A.; Rusakov, S. V.; Terkulov, A.; Baskakov, A.; Belyaev, A.; Boos, E.; Bunichev, V.; Dubinin, M.; Dudko, L.; Ershov, A.; Gribushin, A.; Klyukhin, V.; Kodolova, O.; Lokhtin, I.; Miagkov, I.; Obraztsov, S.; Petrushanko, S.; Savrin, V.; Blinov, V.; Skovpen, Y.; Azhgirey, I.; Bayshev, I.; Bitioukov, S.; Elumakhov, D.; Kachanov, V.; Kalinin, A.; Konstantinov, D.; Krychkine, V.; Petrov, V.; Ryutin, R.; Sobol, A.; Troshin, S.; Tyurin, N.; Uzunian, A.; Volkov, A.; Adzic, P.; Cirkovic, P.; Devetak, D.; Dordevic, M.; Milosevic, J.; Rekovic, V.; Alcaraz Maestre, J.; Barrio Luna, M.; Calvo, E.; Cerrada, M.; Chamizo Llatas, M.; Colino, N.; De La Cruz, B.; Delgado Peris, A.; Escalante Del Valle, A.; Fernandez Bedoya, C.; Fernández Ramos, J. P.; Flix, J.; Fouz, M. C.; Garcia-Abia, P.; Gonzalez Lopez, O.; Goy Lopez, S.; Hernandez, J. M.; Josa, M. I.; Navarro De Martino, E.; Pérez-Calero Yzquierdo, A.; Puerta Pelayo, J.; Quintario Olmeda, A.; Redondo, I.; Romero, L.; Soares, M. S.; de Trocóniz, J. F.; Missiroli, M.; Moran, D.; Cuevas, J.; Fernandez Menendez, J.; Gonzalez Caballero, I.; González Fernández, J. R.; Palencia Cortezon, E.; Sanchez Cruz, S.; Suárez Andrés, I.; Vizan Garcia, J. M.; Cabrillo, I. J.; Calderon, A.; Castiñeiras De Saa, J. R.; Curras, E.; Fernandez, M.; Garcia-Ferrero, J.; Gomez, G.; Lopez Virto, A.; Marco, J.; Martinez Rivero, C.; Matorras, F.; Piedra Gomez, J.; Rodrigo, T.; Ruiz-Jimeno, A.; Scodellaro, L.; Trevisani, N.; Vila, I.; Vilar Cortabitarte, R.; Abbaneo, D.; Auffray, E.; Auzinger, G.; Bachtis, M.; Baillon, P.; Ball, A. H.; Barney, D.; Bloch, P.; Bocci, A.; Bonato, A.; Botta, C.; Camporesi, T.; Castello, R.; Cepeda, M.; Cerminara, G.; D'Alfonso, M.; d'Enterria, D.; Dabrowski, A.; Daponte, V.; David, A.; De Gruttola, M.; De Roeck, A.; Di Marco, E.; Dobson, M.; Dorney, B.; du Pree, T.; Duggan, D.; Dünser, M.; Dupont, N.; Elliott-Peisert, A.; Fartoukh, S.; Franzoni, G.; Fulcher, J.; Funk, W.; Gigi, D.; Gill, K.; Girone, M.; Glege, F.; Gulhan, D.; Gundacker, S.; Guthoff, M.; Hammer, J.; Harris, P.; Hegeman, J.; Innocente, V.; Janot, P.; Kieseler, J.; Kirschenmann, H.; Knünz, V.; Kornmayer, A.; Kortelainen, M. J.; Kousouris, K.; Krammer, M.; Lange, C.; Lecoq, P.; Lourenço, C.; Lucchini, M. T.; Malgeri, L.; Mannelli, M.; Martelli, A.; Meijers, F.; Merlin, J. A.; Mersi, S.; Meschi, E.; Moortgat, F.; Morovic, S.; Mulders, M.; Neugebauer, H.; Orfanelli, S.; Orsini, L.; Pape, L.; Perez, E.; Peruzzi, M.; Petrilli, A.; Petrucciani, G.; Pfeiffer, A.; Pierini, M.; Racz, A.; Reis, T.; Rolandi, G.; Rovere, M.; Ruan, M.; Sakulin, H.; Sauvan, J. B.; Schäfer, C.; Schwick, C.; Seidel, M.; Sharma, A.; Silva, P.; Sphicas, P.; Steggemann, J.; Stoye, M.; Takahashi, Y.; Tosi, M.; Treille, D.; Triossi, A.; Tsirou, A.; Veckalns, V.; Veres, G. I.; Wardle, N.; Wöhri, H. K.; Zagozdzinska, A.; Zeuner, W. D.; Bertl, W.; Deiters, K.; Erdmann, W.; Horisberger, R.; Ingram, Q.; Kaestli, H. C.; Kotlinski, D.; Langenegger, U.; Rohe, T.; Bachmair, F.; Bäni, L.; Bianchini, L.; Casal, B.; Dissertori, G.; Dittmar, M.; Donegà, M.; Grab, C.; Heidegger, C.; Hits, D.; Hoss, J.; Kasieczka, G.; Lecomte, P.; Lustermann, W.; Mangano, B.; Marionneau, M.; Martinez Ruiz del Arbol, P.; Masciovecchio, M.; Meinhard, M. T.; Meister, D.; Micheli, F.; Musella, P.; Nessi-Tedaldi, F.; Pandolfi, F.; Pata, J.; Pauss, F.; Perrin, G.; Perrozzi, L.; Quittnat, M.; Rossini, M.; Schönenberger, M.; Starodumov, A.; Tavolaro, V. R.; Theofilatos, K.; Wallny, R.; Aarrestad, T. K.; Amsler, C.; Caminada, L.; Canelli, M. F.; De Cosa, A.; Galloni, C.; Hinzmann, A.; Hreus, T.; Kilminster, B.; Ngadiuba, J.; Pinna, D.; Rauco, G.; Robmann, P.; Salerno, D.; Yang, Y.; Zucchetta, A.; Candelise, V.; Doan, T. H.; Jain, Sh.; Khurana, R.; Konyushikhin, M.; Kuo, C. M.; Lin, W.; Lu, Y. J.; Pozdnyakov, A.; Yu, S. S.; Kumar, Arun; Chang, P.; Chang, Y. H.; Chang, Y. W.; Chao, Y.; Chen, K. F.; Chen, P. H.; Dietz, C.; Fiori, F.; Hou, W.-S.; Hsiung, Y.; Liu, Y. F.; Lu, R.-S.; Miñano Moya, M.; Paganis, E.; Psallidas, A.; Tsai, J. f.; Tzeng, Y. M.; Asavapibhop, B.; Singh, G.; Srimanobhas, N.; Suwonjandee, N.; Adiguzel, A.; Bakirci, M. N.; Damarseckin, S.; Demiroglu, Z. S.; Dozen, C.; Eskut, E.; Girgis, S.; Gokbulut, G.; Guler, Y.; Hos, I.; Kangal, E. E.; Kara, O.; Kiminsu, U.; Oglakci, M.; Onengut, G.; Ozdemir, K.; Ozturk, S.; Polatoz, A.; Sunar Cerci, D.; Turkcapar, S.; Zorbakir, I. S.; Zorbilmez, C.; Bilin, B.; Bilmis, S.; Isildak, B.; Karapinar, G.; Yalvac, M.; Zeyrek, M.; Gülmez, E.; Kaya, M.; Kaya, O.; Yetkin, E. A.; Yetkin, T.; Cakir, A.; Cankocak, K.; Sen, S.; Grynyov, B.; Levchuk, L.; Sorokin, P.; Aggleton, R.; Ball, F.; Beck, L.; Brooke, J. J.; Burns, D.; Clement, E.; Cussans, D.; Flacher, H.; Goldstein, J.; Grimes, M.; Heath, G. P.; Heath, H. F.; Jacob, J.; Kreczko, L.; Lucas, C.; Newbold, D. M.; Paramesvaran, S.; Poll, A.; Sakuma, T.; Seif El Nasr-storey, S.; Smith, D.; Smith, V. J.; Bell, K. W.; Belyaev, A.; Brew, C.; Brown, R. M.; Calligaris, L.; Cieri, D.; Cockerill, D. J. A.; Coughlan, J. A.; Harder, K.; Harper, S.; Olaiya, E.; Petyt, D.; Shepherd-Themistocleous, C. H.; Thea, A.; Tomalin, I. R.; Williams, T.; Baber, M.; Bainbridge, R.; Buchmuller, O.; Bundock, A.; Burton, D.; Casasso, S.; Citron, M.; Colling, D.; Corpe, L.; Dauncey, P.; Davies, G.; De Wit, A.; Della Negra, M.; Di Maria, R.; Dunne, P.; Elwood, A.; Futyan, D.; Haddad, Y.; Hall, G.; Iles, G.; James, T.; Lane, R.; Laner, C.; Lucas, R.; Lyons, L.; Magnan, A.-M.; Malik, S.; Mastrolorenzo, L.; Nash, J.; Nikitenko, A.; Pela, J.; Penning, B.; Pesaresi, M.; Raymond, D. M.; Richards, A.; Rose, A.; Seez, C.; Summers, S.; Tapper, A.; Uchida, K.; Vazquez Acosta, M.; Virdee, T.; Wright, J.; Zenz, S. C.; Cole, J. E.; Hobson, P. R.; Khan, A.; Kyberd, P.; Leslie, D.; Reid, I. D.; Symonds, P.; Teodorescu, L.; Turner, M.; Borzou, A.; Call, K.; Dittmann, J.; Hatakeyama, K.; Liu, H.; Pastika, N.; Charaf, O.; Cooper, S. I.; Henderson, C.; Rumerio, P.; West, C.; Arcaro, D.; Avetisyan, A.; Bose, T.; Gastler, D.; Rankin, D.; Richardson, C.; Rohlf, J.; Sulak, L.; Zou, D.; Benelli, G.; Berry, E.; Cutts, D.; Garabedian, A.; Hakala, J.; Heintz, U.; Hogan, J. M.; Jesus, O.; Kwok, K. H. M.; Laird, E.; Landsberg, G.; Mao, Z.; Narain, M.; Piperov, S.; Sagir, S.; Spencer, E.; Syarif, R.; Breedon, R.; Breto, G.; Burns, D.; Calderon De La Barca Sanchez, M.; Chauhan, S.; Chertok, M.; Conway, J.; Conway, R.; Cox, P. T.; Erbacher, R.; Flores, C.; Funk, G.; Gardner, M.; Ko, W.; Lander, R.; Mclean, C.; Mulhearn, M.; Pellett, D.; Pilot, J.; Shalhout, S.; Smith, J.; Squires, M.; Stolp, D.; Tripathi, M.; Wilbur, S.; Yohay, R.; Cousins, R.; Everaerts, P.; Florent, A.; Hauser, J.; Ignatenko, M.; Saltzberg, D.; Takasugi, E.; Valuev, V.; Weber, M.; Burt, K.; Clare, R.; Ellison, J.; Gary, J. W.; Ghiasi Shirazi, S. M. A.; Hanson, G.; Heilman, J.; Jandir, P.; Kennedy, E.; Lacroix, F.; Long, O. R.; Olmedo Negrete, M.; Paneva, M. I.; Shrinivas, A.; Si, W.; Wei, H.; Wimpenny, S.; Yates, B. R.; Branson, J. G.; Cerati, G. B.; Cittolin, S.; Derdzinski, M.; Gerosa, R.; Holzner, A.; Klein, D.; Krutelyov, V.; Letts, J.; Macneill, I.; Olivito, D.; Padhi, S.; Pieri, M.; Sani, M.; Sharma, V.; Simon, S.; Tadel, M.; Vartak, A.; Wasserbaech, S.; Welke, C.; Wood, J.; Würthwein, F.; Yagil, A.; Zevi Della Porta, G.; Bhandari, R.; Bradmiller-Feld, J.; Campagnari, C.; Dishaw, A.; Dutta, V.; Flowers, K.; Franco Sevilla, M.; Geffert, P.; George, C.; Golf, F.; Gouskos, L.; Gran, J.; Heller, R.; Incandela, J.; Mccoll, N.; Mullin, S. D.; Ovcharova, A.; Richman, J.; Stuart, D.; Suarez, I.; Yoo, J.; Anderson, D.; Apresyan, A.; Bendavid, J.; Bornheim, A.; Bunn, J.; Chen, Y.; Duarte, J.; Lawhorn, J. M.; Mott, A.; Newman, H. B.; Pena, C.; Spiropulu, M.; Vlimant, J. R.; Xie, S.; Zhu, R. Y.; Andrews, M. B.; Azzolini, V.; Ferguson, T.; Paulini, M.; Russ, J.; Sun, M.; Vogel, H.; Vorobiev, I.; Cumalat, J. P.; Ford, W. T.; Jensen, F.; Johnson, A.; Krohn, M.; Mulholland, T.; Stenson, K.; Wagner, S. R.; Alexander, J.; Chaves, J.; Chu, J.; Dittmer, S.; Mcdermott, K.; Mirman, N.; Nicolas Kaufman, G.; Patterson, J. R.; Rinkevicius, A.; Ryd, A.; Skinnari, L.; Soffi, L.; Tan, S. M.; Tao, Z.; Thom, J.; Tucker, J.; Wittich, P.; Zientek, M.; Winn, D.; Abdullin, S.; Albrow, M.; Apollinari, G.; Banerjee, S.; Bauerdick, L. A. T.; Beretvas, A.; Berryhill, J.; Bhat, P. C.; Bolla, G.; Burkett, K.; Butler, J. N.; Cheung, H. W. K.; Chlebana, F.; Cihangir, S.; Cremonesi, M.; Elvira, V. D.; Fisk, I.; Freeman, J.; Gottschalk, E.; Gray, L.; Green, D.; Grünendahl, S.; Gutsche, O.; Hare, D.; Harris, R. M.; Hasegawa, S.; Hirschauer, J.; Hu, Z.; Jayatilaka, B.; Jindariani, S.; Johnson, M.; Joshi, U.; Klima, B.; Kreis, B.; Lammel, S.; Linacre, J.; Lincoln, D.; Lipton, R.; Liu, M.; Liu, T.; Lopes De Sá, R.; Lykken, J.; Maeshima, K.; Magini, N.; Marraffino, J. M.; Maruyama, S.; Mason, D.; McBride, P.; Merkel, P.; Mrenna, S.; Nahn, S.; Newman-Holmes, C.; O'Dell, V.; Pedro, K.; Prokofyev, O.; Rakness, G.; Ristori, L.; Sexton-Kennedy, E.; Soha, A.; Spalding, W. J.; Spiegel, L.; Stoynev, S.; Strobbe, N.; Taylor, L.; Tkaczyk, S.; Tran, N. V.; Uplegger, L.; Vaandering, E. W.; Vernieri, C.; Verzocchi, M.; Vidal, R.; Wang, M.; Weber, H. A.; Whitbeck, A.; Acosta, D.; Avery, P.; Bortignon, P.; Bourilkov, D.; Brinkerhoff, A.; Carnes, A.; Carver, M.; Curry, D.; Das, S.; Field, R. D.; Furic, I. K.; Konigsberg, J.; Korytov, A.; Ma, P.; Matchev, K.; Mei, H.; Milenovic, P.; Mitselmakher, G.; Rank, D.; Shchutska, L.; Sperka, D.; Thomas, L.; Wang, J.; Wang, S.; Yelton, J.; Linn, S.; Markowitz, P.; Martinez, G.; Rodriguez, J. L.; Ackert, A.; Adams, J. R.; Adams, T.; Askew, A.; Bein, S.; Diamond, B.; Hagopian, S.; Hagopian, V.; Johnson, K. F.; Khatiwada, A.; Prosper, H.; Santra, A.; Weinberg, M.; Baarmand, M. M.; Bhopatkar, V.; Colafranceschi, S.; Hohlmann, M.; Noonan, D.; Roy, T.; Yumiceva, F.; Adams, M. R.; Apanasevich, L.; Berry, D.; Betts, R. R.; Bucinskaite, I.; Cavanaugh, R.; Evdokimov, O.; Gauthier, L.; Gerber, C. E.; Hofman, D. J.; Jung, K.; Kurt, P.; O'Brien, C.; Sandoval Gonzalez, I. D.; Turner, P.; Varelas, N.; Wang, H.; Wu, Z.; Zakaria, M.; Zhang, J.; Bilki, B.; Clarida, W.; Dilsiz, K.; Durgut, S.; Gandrajula, R. P.; Haytmyradov, M.; Khristenko, V.; Merlo, J.-P.; Mermerkaya, H.; Mestvirishvili, A.; Moeller, A.; Nachtman, J.; Ogul, H.; Onel, Y.; Ozok, F.; Penzo, A.; Snyder, C.; Tiras, E.; Wetzel, J.; Yi, K.; Anderson, I.; Blumenfeld, B.; Cocoros, A.; Eminizer, N.; Fehling, D.; Feng, L.; Gritsan, A. V.; Maksimovic, P.; Martin, C.; Osherson, M.; Roskes, J.; Sarica, U.; Swartz, M.; Xiao, M.; Xin, Y.; You, C.; Al-bataineh, A.; Baringer, P.; Bean, A.; Boren, S.; Bowen, J.; Bruner, C.; Castle, J.; Forthomme, L.; Kenny, R. P., III; Kropivnitskaya, A.; Majumder, D.; Mcbrayer, W.; Murray, M.; Sanders, S.; Stringer, R.; Tapia Takaki, J. D.; Wang, Q.; Ivanov, A.; Kaadze, K.; Khalil, S.; Maravin, Y.; Mohammadi, A.; Saini, L. K.; Skhirtladze, N.; Toda, S.; Rebassoo, F.; Wright, D.; Anelli, C.; Baden, A.; Baron, O.; Belloni, A.; Calvert, B.; Eno, S. C.; Ferraioli, C.; Gomez, J. A.; Hadley, N. J.; Jabeen, S.; Kellogg, R. G.; Kolberg, T.; Kunkle, J.; Lu, Y.; Mignerey, A. C.; Ricci-Tam, F.; Shin, Y. H.; Skuja, A.; Tonjes, M. B.; Tonwar, S. C.; Abercrombie, D.; Allen, B.; Apyan, A.; Barbieri, R.; Baty, A.; Bi, R.; Bierwagen, K.; Brandt, S.; Busza, W.; Cali, I. A.; Demiragli, Z.; Di Matteo, L.; Gomez Ceballos, G.; Goncharov, M.; Hsu, D.; Iiyama, Y.; Innocenti, G. M.; Klute, M.; Kovalskyi, D.; Krajczar, K.; Lai, Y. S.; Lee, Y.-J.; Levin, A.; Luckey, P. D.; Marini, A. C.; Mcginn, C.; Mironov, C.; Narayanan, S.; Niu, X.; Paus, C.; Roland, C.; Roland, G.; Salfeld-Nebgen, J.; Stephans, G. S. F.; Sumorok, K.; Tatar, K.; Varma, M.; Velicanu, D.; Veverka, J.; Wang, J.; Wang, T. W.; Wyslouch, B.; Yang, M.; Zhukova, V.; Benvenuti, A. C.; Chatterjee, R. M.; Evans, A.; Finkel, A.; Gude, A.; Hansen, P.; Kalafut, S.; Kao, S. C.; Kubota, Y.; Lesko, Z.; Mans, J.; Nourbakhsh, S.; Ruckstuhl, N.; Rusack, R.; Tambe, N.; Turkewitz, J.; Acosta, J. G.; Oliveros, S.; Avdeeva, E.; Bartek, R.; Bloom, K.; Claes, D. R.; Dominguez, A.; Fangmeier, C.; Gonzalez Suarez, R.; Kamalieddin, R.; Kravchenko, I.; Malta Rodrigues, A.; Meier, F.; Monroy, J.; Siado, J. E.; Snow, G. R.; Stieger, B.; Alyari, M.; Dolen, J.; George, J.; Godshalk, A.; Harrington, C.; Iashvili, I.; Kaisen, J.; Kharchilava, A.; Kumar, A.; Parker, A.; Rappoccio, S.; Roozbahani, B.; Alverson, G.; Barberis, E.; Hortiangtham, A.; Massironi, A.; Morse, D. M.; Nash, D.; Orimoto, T.; Teixeira De Lima, R.; Trocino, D.; Wang, R.-J.; Wood, D.; Bhattacharya, S.; Hahn, K. A.; Kubik, A.; Kumar, A.; Low, J. F.; Mucia, N.; Odell, N.; Pollack, B.; Schmitt, M. H.; Sung, K.; Trovato, M.; Velasco, M.; Dev, N.; Hildreth, M.; Hurtado Anampa, K.; Jessop, C.; Karmgard, D. J.; Kellams, N.; Lannon, K.; Marinelli, N.; Meng, F.; Mueller, C.; Musienko, Y.; Planer, M.; Reinsvold, A.; Ruchti, R.; Smith, G.; Taroni, S.; Wayne, M.; Wolf, M.; Woodard, A.; Alimena, J.; Antonelli, L.; Brinson, J.; Bylsma, B.; Durkin, L. S.; Flowers, S.; Francis, B.; Hart, A.; Hill, C.; Hughes, R.; Ji, W.; Liu, B.; Luo, W.; Puigh, D.; Winer, B. L.; Wulsin, H. W.; Cooperstein, S.; Driga, O.; Elmer, P.; Hardenbrook, J.; Hebda, P.; Lange, D.; Luo, J.; Marlow, D.; Medvedeva, T.; Mei, K.; Mooney, M.; Olsen, J.; Palmer, C.; Piroué, P.; Stickland, D.; Tully, C.; Zuranski, A.; Malik, S.; Barker, A.; Barnes, V. E.; Folgueras, S.; Gutay, L.; Jha, M. K.; Jones, M.; Jung, A. W.; Miller, D. H.; Neumeister, N.; Schulte, J. F.; Shi, X.; Sun, J.; Svyatkovskiy, A.; Wang, F.; Xie, W.; Xu, L.; Parashar, N.; Stupak, J.; Adair, A.; Akgun, B.; Chen, Z.; Ecklund, K. M.; Geurts, F. J. M.; Guilbaud, M.; Li, W.; Michlin, B.; Northup, M.; Padley, B. P.; Redjimi, R.; Roberts, J.; Rorie, J.; Tu, Z.; Zabel, J.; Betchart, B.; Bodek, A.; de Barbaro, P.; Demina, R.; Duh, Y. t.; Ferbel, T.; Galanti, M.; Garcia-Bellido, A.; Han, J.; Hindrichs, O.; Khukhunaishvili, A.; Lo, K. H.; Tan, P.; Verzetti, M.; Agapitos, A.; Chou, J. P.; Contreras-Campana, E.; Gershtein, Y.; Gómez Espinosa, T. A.; Halkiadakis, E.; Heindl, M.; Hidas, D.; Hughes, E.; Kaplan, S.; Kunnawalkam Elayavalli, R.; Kyriacou, S.; Lath, A.; Nash, K.; Saka, H.; Salur, S.; Schnetzer, S.; Sheffield, D.; Somalwar, S.; Stone, R.; Thomas, S.; Thomassen, P.; Walker, M.; Delannoy, A. G.; Foerster, M.; Heideman, J.; Riley, G.; Rose, K.; Spanier, S.; Thapa, K.; Bouhali, O.; Celik, A.; Dalchenko, M.; De Mattia, M.; Delgado, A.; Dildick, S.; Eusebi, R.; Gilmore, J.; Huang, T.; Juska, E.; Kamon, T.; Mueller, R.; Pakhotin, Y.; Patel, R.; Perloff, A.; Perniè, L.; Rathjens, D.; Rose, A.; Safonov, A.; Tatarinov, A.; Ulmer, K. A.; Akchurin, N.; Cowden, C.; Damgov, J.; De Guio, F.; Dragoiu, C.; Dudero, P. R.; Faulkner, J.; Gurpinar, E.; Kunori, S.; Lamichhane, K.; Lee, S. W.; Libeiro, T.; Peltola, T.; Undleeb, S.; Volobouev, I.; Wang, Z.; Greene, S.; Gurrola, A.; Janjam, R.; Johns, W.; Maguire, C.; Melo, A.; Ni, H.; Sheldon, P.; Tuo, S.; Velkovska, J.; Xu, Q.; Arenton, M. W.; Barria, P.; Cox, B.; Goodell, J.; Hirosky, R.; Ledovskoy, A.; Li, H.; Neu, C.; Sinthuprasith, T.; Sun, X.; Wang, Y.; Wolfe, E.; Xia, F.; Clarke, C.; Harr, R.; Karchin, P. E.; Sturdy, J.; Belknap, D. A.; Dasu, S.; Dodd, L.; Duric, S.; Gomber, B.; Grothe, M.; Herndon, M.; Hervé, A.; Klabbers, P.; Lanaro, A.; Levine, A.; Long, K.; Loveless, R.; Ojalvo, I.; Perry, T.; Pierro, G. A.; Polese, G.; Ruggles, T.; Savin, A.; Smith, N.; Smith, W. H.; Taylor, D.; Woods, N.; CMS Collaboration

    2017-06-01

    The results of a search for new physics in final states with photons and missing transverse energy are reported. The study is based on a sample of proton-proton collisions collected at a center-of-mass energy of 13 TeV with the CMS detector in 2015, corresponding to an integrated luminosity of 2.3 fb-1. Final states with two photons and significant missing transverse energy are used to search for supersymmetric particles in models of supersymmetry (SUSY) with general gauge-mediated (GGM) supersymmetry breaking. No excess is observed with respect to the standard model expectation, and the results are used to set limits on gluino pair production and squark pair production in the GGM SUSY framework. Gluino masses below 1.65 TeV and squark masses below 1.37 TeV are excluded at a 95% confidence level.

  16. Sensitivity to imputation models and assumptions in receiver operating characteristic analysis with incomplete data

    PubMed Central

    Karakaya, Jale; Karabulut, Erdem; Yucel, Recai M.

    2015-01-01

    Modern statistical methods using incomplete data have been increasingly applied in a wide variety of substantive problems. Similarly, receiver operating characteristic (ROC) analysis, a method used in evaluating diagnostic tests or biomarkers in medical research, has also been increasingly popular problem in both its development and application. While missing-data methods have been applied in ROC analysis, the impact of model mis-specification and/or assumptions (e.g. missing at random) underlying the missing data has not been thoroughly studied. In this work, we study the performance of multiple imputation (MI) inference in ROC analysis. Particularly, we investigate parametric and non-parametric techniques for MI inference under common missingness mechanisms. Depending on the coherency of the imputation model with the underlying data generation mechanism, our results show that MI generally leads to well-calibrated inferences under ignorable missingness mechanisms. PMID:26379316

  17. [Imputing missing data in public health: general concepts and application to dichotomous variables].

    PubMed

    Hernández, Gilma; Moriña, David; Navarro, Albert

    The presence of missing data in collected variables is common in health surveys, but the subsequent imputation thereof at the time of analysis is not. Working with imputed data may have certain benefits regarding the precision of the estimators and the unbiased identification of associations between variables. The imputation process is probably still little understood by many non-statisticians, who view this process as highly complex and with an uncertain goal. To clarify these questions, this note aims to provide a straightforward, non-exhaustive overview of the imputation process to enable public health researchers ascertain its strengths. All this in the context of dichotomous variables which are commonplace in public health. To illustrate these concepts, an example in which missing data is handled by means of simple and multiple imputation is introduced. Copyright © 2017 SESPAS. Publicado por Elsevier España, S.L.U. All rights reserved.

  18. Search for supersymmetry in events with photons and missing transverse energy in pp collisions at 13 TeV

    DOE PAGES

    Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; ...

    2017-04-07

    Results of a search for new physics in final states with photons and missing transverse energy are reported. The study is based on a sample of proton–proton collisions collected at a center-of-mass energy of 13 TeV with the CMS detector in 2015, corresponding to an integrated luminosity of 2.3 fb -1. Final states with two photons and significant missing transverse energy are used to search for supersymmetric particles in models of supersymmetry (SUSY) with general gauge-mediated (GGM) supersymmetry breaking. We did not observe an excess with respect to the standard model expectation, and the results are used to set limitsmore » on gluino pair production and squark pair production in the GGM SUSY framework. Gluino masses below 1.65 TeV and squark masses below 1.37 TeV are excluded at a 95% confidence level.« less

  19. The absence of genes for cytochrome c oxidase and reductase subunits in maxicircle kinetoplast DNA of the respiration-deficient plant trypanosomatid Phytomonas serpens.

    PubMed

    Nawathean, P; Maslov, D A

    2000-08-01

    By completing the sequencing of the maxicircle conserved region in the kinetoplast DNA of Phytomonas serpens, we showed that the genes for subunits I and II (COI and COII) of cytochrome c oxidase in this organism were missing. We had previously shown that the genes for cytochrome c oxidase subunit III and apocytochrome b were also missing. These deletions did not affect the structure or expression of the remaining genes. Partial editing of the mRNA for NADH dehydrogenase subunit 8, previously found in strain IG from insects, was complete in two other strains isolated from plants. The appearance of a novel maxicircle gene for MURF2 block I gRNA, which substitutes for the gene missing due to the COII gene deletion, may illustrate a general mechanism for the origin of gRNAs.

  20. Accounting for informatively missing data in logistic regression by means of reassessment sampling.

    PubMed

    Lin, Ji; Lyles, Robert H

    2015-05-20

    We explore the 'reassessment' design in a logistic regression setting, where a second wave of sampling is applied to recover a portion of the missing data on a binary exposure and/or outcome variable. We construct a joint likelihood function based on the original model of interest and a model for the missing data mechanism, with emphasis on non-ignorable missingness. The estimation is carried out by numerical maximization of the joint likelihood function with close approximation of the accompanying Hessian matrix, using sharable programs that take advantage of general optimization routines in standard software. We show how likelihood ratio tests can be used for model selection and how they facilitate direct hypothesis testing for whether missingness is at random. Examples and simulations are presented to demonstrate the performance of the proposed method. Copyright © 2015 John Wiley & Sons, Ltd.

  1. SU-E-T-310: Targeting Safety Improvements Through Analysis of Near-Miss Error Detection Points in An Incident Learning Database

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Novak, A; Nyflot, M; Sponseller, P

    2014-06-01

    Purpose: Radiation treatment planning involves a complex workflow that can make safety improvement efforts challenging. This study utilizes an incident reporting system to identify detection points of near-miss errors, in order to guide our departmental safety improvement efforts. Previous studies have examined where errors arise, but not where they are detected or their patterns. Methods: 1377 incidents were analyzed from a departmental nearmiss error reporting system from 3/2012–10/2013. All incidents were prospectively reviewed weekly by a multi-disciplinary team, and assigned a near-miss severity score ranging from 0–4 reflecting potential harm (no harm to critical). A 98-step consensus workflow was usedmore » to determine origination and detection points of near-miss errors, categorized into 7 major steps (patient assessment/orders, simulation, contouring/treatment planning, pre-treatment plan checks, therapist/on-treatment review, post-treatment checks, and equipment issues). Categories were compared using ANOVA. Results: In the 7-step workflow, 23% of near-miss errors were detected within the same step in the workflow, while an additional 37% were detected by the next step in the workflow, and 23% were detected two steps downstream. Errors detected further from origination were more severe (p<.001; Figure 1). The most common source of near-miss errors was treatment planning/contouring, with 476 near misses (35%). Of those 476, only 72(15%) were found before leaving treatment planning, 213(45%) were found at physics plan checks, and 191(40%) were caught at the therapist pre-treatment chart review or on portal imaging. Errors that passed through physics plan checks and were detected by therapists were more severe than other errors originating in contouring/treatment planning (1.81 vs 1.33, p<0.001). Conclusion: Errors caught by radiation treatment therapists tend to be more severe than errors caught earlier in the workflow, highlighting the importance of safety checks in dosimetry and physics. We are utilizing our findings to improve manual and automated checklists for dosimetry and physics.« less

  2. Treatment dropout and missed appointments among adults with attention-deficit/hyperactivity disorder: associations with patient- and disorder-related factors.

    PubMed

    Soendergaard, Helle M; Thomsen, Per H; Pedersen, Pernille; Pedersen, Erik; Poulsen, Agnethe E; Nielsen, Jette M; Winther, Lars; Henriksen, Anne; Rungoe, Berit; Soegaard, Hans J

    2016-02-01

    Knowledge of factors associated with treatment dropout and missed appointments in adults with attention-deficit/hyperactivity disorder (ADHD) is very limited. On the basis of proposed hypotheses that past behavior patterns are more predictive of current behaviors of treatment dropout and missed appointments than are sociodemographic and clinical characteristics, we examined the associations of sociodemographic variables, clinical variables, risk-taking behavior, educational and occupational instability, and behaviors during mandatory schooling with the primary outcome measures of treatment dropout and missed appointments. In a naturalistic cohort study of 151 adult outpatients with ADHD initiating assessment in a Danish ADHD unit from September 1, 2010, to September 1, 2011, the Adult ADHD Self-Report Scale v1.1 symptom checklist (ASRS) and a thorough clinical interview were used to assess ADHD according to DSM-IV-TR criteria. Stepwise logistic regression analysis was used to estimate reported associations. A total of 27% of patients dropped out of treatment and a total of 42% had ≥ 3 missed appointments during treatment. Mood and anxiety disorders significantly lowered the odds of treatment dropout (odds ratio [OR] = 0.18; 95% confidence interval [CI], 0.05-0.65), whereas having started but not completed 2 or more educational programs apart from mandatory schooling significantly increased the odds of dropout (OR = 3.01; 95% CI, 1.32-6.89). Variables significantly associated with most missed appointments were low educational level (OR = 2.19; 95% CI, 1.12-4.31), 3 or more employments of less than 3 months' duration (OR = 2.86; 95% CI, 1.30-6.28), and having skipped class often/very often during mandatory schooling (OR = 2.65; 95% CI, 1.29-5.43). Additionally, the predominantly inattentive ADHD (ADHD-I) subtype lowered the odds of missed appointments (OR = 0.17; 95% CI, 0.05-0.62). Our results suggest that past behavior in terms of highest dropout rates in the educational and occupational systems and highest rates of skipping class during mandatory schooling is equally associated with current behavior of treatment dropout and missed appointments as are sociodemographic and clinical factors. ClinicalTrials.gov identifier: NCT02226445. © Copyright 2015 Physicians Postgraduate Press, Inc.

  3. Reviews Exhibitions: Collider: Step inside the World's Greatest Experiment Equipment: Hero Steam Turbine Classroom Video: Most of Our Universe is Missing Book: Serving the Reich Book: Breakthrough to CLIL for Physics Book: The Good Research Guide Apps: Popplet Web Watch Apps

    NASA Astrophysics Data System (ADS)

    2014-03-01

    WE RECOMMEND Collider: step inside the world's greatest experiment A great exhibition at the Science Museum in London Hero Steam Turbine Superb engine model gets up to 2500 rpm Most of Our Universe is Missing BBC video explores the dark truth Serving the Reich Science and morality in Nazi Germany The Good Research Guide A non-specialist book for teachers starting out in education research WORTH A LOOK Breakthrough to CLIL for Physics A book based on a physics curriculum for non-English students WEB WATCH Electric cycles online: patterns of use APPS The virtual laboratory advances personal skills

  4. Piloted simulation study of an ILS approach of a twin-pusher business/commuter turboprop aircraft configuration

    NASA Technical Reports Server (NTRS)

    Riley, Donald R.; Brandon, Jay M.; Glaab, Louis J.

    1994-01-01

    A six-degree-of-freedom nonlinear simulation of a twin-pusher, turboprop business/commuter aircraft configuration representative of the Cessna ATPTB (Advanced turboprop test bed) was developed for use in piloted studies with the Langley General Aviation Simulator. The math models developed are provided, simulation predictions are compared with with Cessna flight-test data for validation purposes, and results of a handling quality study during simulated ILS (instrument landing system) approaches and missed approaches are presented. Simulated flight trajectories, task performance measures, and pilot evaluations are presented for the ILS approach and missed-approach tasks conducted with the vehicle in the presence of moderate turbulence, varying horizontal winds and engine-out conditions. Six test subjects consisting of two research pilots, a Cessna test pilot, and three general aviation pilots participated in the study. This effort was undertaken in cooperation with the Cessna Aircraft Company.

  5. A complete solution classification and unified algorithmic treatment for the one- and two-step asymmetric S-transverse mass event scale statistic

    NASA Astrophysics Data System (ADS)

    Walker, Joel W.

    2014-08-01

    The M T2, or "s-transverse mass", statistic was developed to associate a parent mass scale to a missing transverse energy signature, given that escaping particles are generally expected in pairs, while collider experiments are sensitive to just a single transverse momentum vector sum. This document focuses on the generalized extension of that statistic to asymmetric one- and two-step decay chains, with arbitrary child particle masses and upstream missing transverse momentum. It provides a unified theoretical formulation, complete solution classification, taxonomy of critical points, and technical algorithmic prescription for treatment of the event scale. An implementation of the described algorithm is available for download, and is also a deployable component of the author's selection cut software package AEAC uS (Algorithmic Event Arbiter and C ut Selector). appendices address combinatoric event assembly, algorithm validation, and a complete pseudocode.

  6. Multiple imputation for IPD meta-analysis: allowing for heterogeneity and studies with missing covariates.

    PubMed

    Quartagno, M; Carpenter, J R

    2016-07-30

    Recently, multiple imputation has been proposed as a tool for individual patient data meta-analysis with sporadically missing observations, and it has been suggested that within-study imputation is usually preferable. However, such within study imputation cannot handle variables that are completely missing within studies. Further, if some of the contributing studies are relatively small, it may be appropriate to share information across studies when imputing. In this paper, we develop and evaluate a joint modelling approach to multiple imputation of individual patient data in meta-analysis, with an across-study probability distribution for the study specific covariance matrices. This retains the flexibility to allow for between-study heterogeneity when imputing while allowing (i) sharing information on the covariance matrix across studies when this is appropriate, and (ii) imputing variables that are wholly missing from studies. Simulation results show both equivalent performance to the within-study imputation approach where this is valid, and good results in more general, practically relevant, scenarios with studies of very different sizes, non-negligible between-study heterogeneity and wholly missing variables. We illustrate our approach using data from an individual patient data meta-analysis of hypertension trials. © 2015 The Authors. Statistics in Medicine Published by John Wiley & Sons Ltd. © 2015 The Authors. Statistics in Medicine Published by John Wiley & Sons Ltd.

  7. Why near-miss events can decrease an individual's protective response to hurricanes.

    PubMed

    Dillon, Robin L; Tinsley, Catherine H; Cronin, Matthew

    2011-03-01

    Prior research shows that when people perceive the risk of some hazardous event to be low, they are unlikely to engage in mitigation activities for the potential hazard. We believe one factor that can lower inappropriately (from a normative perspective) people's perception of the risk of a hazard is information about prior near-miss events. A near-miss occurs when an event (such as a hurricane), which had some nontrivial probability of ending in disaster (loss of life, property damage), does not because good fortune intervenes. People appear to mistake such good fortune as an indicator of resiliency. In our first study, people with near-miss information were less likely to purchase flood insurance, and this was shown for both participants from the general population and individuals with specific interests in risk and natural disasters. In our second study, we consider a different mitigation decision, that is, to evacuate from a hurricane, and vary the level of statistical probability of hurricane damage. We still found a strong effect for near-miss information. Our research thus shows how people who have experienced a similar situation but escape damage because of chance will make decisions consistent with a perception that the situation is less risky than those without the past experience. We end by discussing the implications for risk communication. © 2010 Society for Risk Analysis.

  8. Early Elementary Performance and Attendance in Baltimore City Schools' Pre-Kindergarten and Kindergarten

    ERIC Educational Resources Information Center

    Connolly, Faith; Olson, Linda S.

    2012-01-01

    This study looks at attendance in the early grades of elementary school. In particular, the authors focus on students enrolled in Pre-Kindergarten (PreK) and Kindergarten (K). They follow these young students over several years to determine their pattern of chronic absence (CA), defined as missing more than one-ninth of days enrolled, and their…

  9. "STEMming" the Swell of Absenteeism in Urban Middle Grade Schools: Impacts of a Summer Robotics Program

    ERIC Educational Resources Information Center

    Mac Iver, Martha Abele; Mac Iver, Douglas J.

    2014-01-01

    Attendance is probably the most fundamental behavioral indicator of student engagement with school. Though many students fall off-track to success for the first time in ninth grade, poor attendance patterns often begin increasing in middle school and become worse in high school. Missing school during the secondary grades can often be traced to low…

  10. A New Archive and Internet Search Engine May Change the Nature of On-Line Research.

    ERIC Educational Resources Information Center

    Selingo, Jeffrey

    1998-01-01

    In the process of trying to preserve Internet history by archiving it, a company has developed a powerful Internet search engine that provides information on Web site usage patterns, which can act as a relatively objective source of information about information sources and can link sources that a researcher might otherwise miss. However, issues…

  11. More missing VEV mechanism in supersymmetric SO(10) model

    NASA Astrophysics Data System (ADS)

    Berezhiani, Z.; Tavartkiladze, Z.

    1997-02-01

    The anomalous gauge U(1)A symmetry can be a very useful ingredient towards building the complete supersymmetric SO(10) theory. We present an example of the SO(10) × U(1)A model which provides ``all order'' solution to the doublet-triplet splitting problem via the missing VEV mechanism. An interesting feature of the model is that all relevant GUT scales are related to a single dimensional parameter in the Higgs superpotential, which could have a dynamical origin. In this situation the SO(10) symmetry breaks down to the MSSM practically at one step, without intermediate stages. We also present a variant of the model where the colour Higgsino mediated d = 5 operators are naturally suppressed. We also extend the model by implementing U(1)A as a horizontal symmetry for explaining the fermion mass and mixing hierarchy. The obtained pattern of the fermion mass matrices implies a moderate value of tan β (~ 6-10) and leads to the consistent picture for the low energy observables. It also suggests the neutrino mass and mixing pattern that could naturally explain both the solar and atmospheric neutrino problems, respectively through the νe - νμ and νμ - ντ oscillations.

  12. Australian lungfish (Neoceratodus forsteri): a missing link in the evolution of complementary side biases for predator avoidance and prey capture.

    PubMed

    Lippolis, G; Joss, J M P; Rogers, Lesley J

    2009-01-01

    Side biases in behavior, reflecting lateral specializations of the brain, are widespread amongst vertebrates. We studied laterality in the Australian lungfish (Neoceratodus forsteri) to gain insight into the evolution of the complementary specializations of predator avoidance (right hemisphere) and foraging behavior (left hemisphere). Because N. forsteri is the closest extant ancestor of the first land-dwelling vertebrates, knowledge of laterality in this species should provide a missing link in the transition from fish to tetrapods. Predator escape responses were elicited by generating pressure waves and a significant bias for C-start responses to the left side was found. This bias was unaffected by activity levels that change according to a diurnal cycle: activity is higher in the dark phase than the light phase. A complementary bias to turn to the right side was found during feeding behavior. This pattern of opposite-side specializations matches that known for fish, anurans, reptiles, birds and, as some evidence indicates, also mammals. Hence, we conclude that it is a homologous pattern of lateralization that evolved in early aquatic vertebrates and was retained as they made the transition to land-dwelling tetrapods. Copyright 2009 S. Karger AG, Basel.

  13. Conspicuity of target lights: The influence of color

    NASA Technical Reports Server (NTRS)

    Connors, M. M.

    1975-01-01

    The conspicuity (or attention-getting qualities) were investigated of foveally-equated, colored lights, when seen against a star background. Subjects who were periodically engaged in a distracting cockpit task were required to search a large visual field and report the appearance of a target light as quickly as possible. Targets were red, yellow, white, green, and blue, and appeared either as steady or as flashing lights. Results indicate that red targets were missed more frequently and responded to more slowly than lights of other hues. Yellow targets were acquired more slowly than white, green, or blue targets; responses to white targets were significantly slower than responses to green or blue targets. In general, flashing lights were superior to steady lights, but this was not found for all hues. For red, the 2 Hz flash was superior to all other flash rates and to the steady light, none of which differed significantly from each other. Over all hues, conspicuity was found to peak at 2-3 Hz. Response time was found to be fastest, generally, for targets appearing at between 3 and 8 from the center of the visual field. However, this pattern was not repeated for every hue. Conspicuity response times suggest a complex relationship between hue and position in the visual field that is explained only partially by retinal sensitivity.

  14. The sodium-activated potassium channel Slack is required for optimal cognitive flexibility in mice.

    PubMed

    Bausch, Anne E; Dieter, Rebekka; Nann, Yvette; Hausmann, Mario; Meyerdierks, Nora; Kaczmarek, Leonard K; Ruth, Peter; Lukowski, Robert

    2015-07-01

    Kcnt1 encoded sodium-activated potassium channels (Slack channels) are highly expressed throughout the brain where they modulate the firing patterns and general excitability of many types of neurons. Increasing evidence suggests that Slack channels may be important for higher brain functions such as cognition and normal intellectual development. In particular, recent findings have shown that human Slack mutations produce very severe intellectual disability and that Slack channels interact directly with the Fragile X mental retardation protein (FMRP), a protein that when missing or mutated results in Fragile X syndrome (FXS), the most common form of inherited intellectual disability and autism in humans. We have now analyzed a recently developed Kcnt1 null mouse model in several behavioral tasks to assess which aspects of memory and learning are dependent on Slack. We demonstrate that Slack deficiency results in mildly altered general locomotor activity, but normal working memory, reference memory, as well as cerebellar control of motor functions. In contrast, we find that Slack channels are required for cognitive flexibility, including reversal learning processes and the ability to adapt quickly to unfamiliar situations and environments. Our data reveal that hippocampal-dependent spatial learning capabilities require the proper function of Slack channels. © 2015 Bausch et al.; Published by Cold Spring Harbor Laboratory Press.

  15. The sodium-activated potassium channel Slack is required for optimal cognitive flexibility in mice

    PubMed Central

    Bausch, Anne E.; Dieter, Rebekka; Nann, Yvette; Hausmann, Mario; Meyerdierks, Nora; Kaczmarek, Leonard K.

    2015-01-01

    Kcnt1 encoded sodium-activated potassium channels (Slack channels) are highly expressed throughout the brain where they modulate the firing patterns and general excitability of many types of neurons. Increasing evidence suggests that Slack channels may be important for higher brain functions such as cognition and normal intellectual development. In particular, recent findings have shown that human Slack mutations produce very severe intellectual disability and that Slack channels interact directly with the Fragile X mental retardation protein (FMRP), a protein that when missing or mutated results in Fragile X syndrome (FXS), the most common form of inherited intellectual disability and autism in humans. We have now analyzed a recently developed Kcnt1 null mouse model in several behavioral tasks to assess which aspects of memory and learning are dependent on Slack. We demonstrate that Slack deficiency results in mildly altered general locomotor activity, but normal working memory, reference memory, as well as cerebellar control of motor functions. In contrast, we find that Slack channels are required for cognitive flexibility, including reversal learning processes and the ability to adapt quickly to unfamiliar situations and environments. Our data reveal that hippocampal-dependent spatial learning capabilities require the proper function of Slack channels. PMID:26077685

  16. Diel growth dynamics in tree stems: linking anatomy and ecophysiology.

    PubMed

    Steppe, Kathy; Sterck, Frank; Deslauriers, Annie

    2015-06-01

    Impacts of climate on stem growth in trees are studied in anatomical, ecophysiological, and ecological disciplines, but an integrative framework to assess those impacts remains lacking. In this opinion article, we argue that three research efforts are required to provide that integration. First, we need to identify the missing links in diel patterns in stem diameter and stem growth and relate those patterns to the underlying mechanisms that control water and carbon balance. Second, we should focus on the understudied mechanisms responsible for seasonal impacts on such diel patterns. Third, information on stem anatomy and ecophysiology should be integrated in the same experiments and mechanistic plant growth models to capture both diel and seasonal scales. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. A regressive methodology for estimating missing data in rainfall daily time series

    NASA Astrophysics Data System (ADS)

    Barca, E.; Passarella, G.

    2009-04-01

    The "presence" of gaps in environmental data time series represents a very common, but extremely critical problem, since it can produce biased results (Rubin, 1976). Missing data plagues almost all surveys. The problem is how to deal with missing data once it has been deemed impossible to recover the actual missing values. Apart from the amount of missing data, another issue which plays an important role in the choice of any recovery approach is the evaluation of "missingness" mechanisms. When data missing is conditioned by some other variable observed in the data set (Schafer, 1997) the mechanism is called MAR (Missing at Random). Otherwise, when the missingness mechanism depends on the actual value of the missing data, it is called NCAR (Not Missing at Random). This last is the most difficult condition to model. In the last decade interest arose in the estimation of missing data by using regression (single imputation). More recently multiple imputation has become also available, which returns a distribution of estimated values (Scheffer, 2002). In this paper an automatic methodology for estimating missing data is presented. In practice, given a gauging station affected by missing data (target station), the methodology checks the randomness of the missing data and classifies the "similarity" between the target station and the other gauging stations spread over the study area. Among different methods useful for defining the similarity degree, whose effectiveness strongly depends on the data distribution, the Spearman correlation coefficient was chosen. Once defined the similarity matrix, a suitable, nonparametric, univariate, and regressive method was applied in order to estimate missing data in the target station: the Theil method (Theil, 1950). Even though the methodology revealed to be rather reliable an improvement of the missing data estimation can be achieved by a generalization. A first possible improvement consists in extending the univariate technique to the multivariate approach. Another approach follows the paradigm of the "multiple imputation" (Rubin, 1987; Rubin, 1988), which consists in using a set of "similar stations" instead than the most similar. This way, a sort of estimation range can be determined allowing the introduction of uncertainty. Finally, time series can be grouped on the basis of monthly rainfall rates defining classes of wetness (i.e.: dry, moderately rainy and rainy), in order to achieve the estimation using homogeneous data subsets. We expect that integrating the methodology with these enhancements will certainly improve its reliability. The methodology was applied to the daily rainfall time series data registered in the Candelaro River Basin (Apulia - South Italy) from 1970 to 2001. REFERENCES D.B., Rubin, 1976. Inference and Missing Data. Biometrika 63 581-592 D.B. Rubin, 1987. Multiple Imputation for Nonresponce in Surveys, New York: John Wiley & Sons, Inc. D.B. Rubin, 1988. An overview of multiple imputation. In Survey Research Section, pp. 79-84, American Statistical Association, 1988. J.L., Schafer, 1997. Analysis of Incomplete Multivariate Data, Chapman & Hall. J., Scheffer, 2002. Dealing with Missing Data. Res. Lett. Inf. Math. Sci. 3, 153-160. Available online at http://www.massey.ac.nz/~wwiims/research/letters/ H. Theil, 1950. A rank-invariant method of linear and polynomial regression analysis. Indicationes Mathematicae, 12, pp.85-91.

  18. Comparative anatomy, homologies and evolution of the pectoral and forelimb musculature of tetrapods with special attention to extant limbed amphibians and reptiles.

    PubMed

    Abdala, Virginia; Diogo, Rui

    2010-11-01

    The main aim of the present work is to synthesize the information obtained from our dissections of the pectoral and forelimb muscles of representative members of the major extant taxa of limbed amphibians and reptiles and from our review of the literature, in order to provide an account of the comparative anatomy, homologies and evolution of these muscles in the Tetrapoda. The pectoral and forelimb musculature of all these major taxa conform to a general pattern that seems to have been acquired very early in the evolutionary history of tetrapods. Although some muscles are missing in certain taxa, and a clear departure from this general pattern is obviously present in derived groups such as birds, the same overall configuration is easily distinguishable in these taxa. Among the most notable anatomical differences between the groups, one that seems to have relevant evolutionary and functional implications, concerns the distal insertion points of the forearm musculature. In tetrapods, the muscles of the radial and ulnar complexes of the forearm are pleisomorphically mainly inserted onto the radius/ulna or onto the more proximal carpal bones, but in mammals some of these muscles insert more distally onto bones such as the metacarpals. Interestingly, a similar trend towards a more distal insertion of these muscles is also found in some non-mammalian tetrapod taxa, such as some anurans (e.g. Phyllomedusa). This may be correlated with the acquisition of more subtle digital movement abilities in these latter taxa. © 2010 The Authors. Journal of Anatomy © 2010 Anatomical Society of Great Britain and Ireland.

  19. Twentieth anniversary of the European Union health mandate: taking stock of perceived achievements, failures and missed opportunities - a qualitative study.

    PubMed

    Rosenkötter, Nicole; Clemens, Timo; Sørensen, Kristine; Brand, Helmut

    2013-11-14

    The European Union (EU) health mandate was initially defined in the Maastricht Treaty in 1992. The twentieth anniversary of the Treaty offers a unique opportunity to take stock of EU health actions by giving an overview of influential public health related EU-level policy outputs and a summary of policy outputs or actions perceived as an achievement, a failure or a missed opportunity. Semi-structured expert interviews (N = 20) were conducted focusing on EU-level actions that were relevant for health. Respondents were asked to name EU policies or actions that they perceived as an achievement, a failure or a missed opportunity. A directed content analysis approach was used to identify expert perceptions on achievements, failures and missed opportunities in the interviews. Additionally, a nominal group technique was applied to identify influential and public health relevant EU-level policy outputs. The ranking of influential policy outputs resulted in top positions of adjudications and legislations, agencies, European Commission (EC) programmes and strategies, official networks, cooperative structures and exchange efforts, the work on health determinants and uptake of scientific knowledge. The assessment of EU health policies as being an achievement, a failure or a missed opportunity was often characterized by diverging respondent views. Recurring topics that emerged were the Directorate General for Health and Consumers (DG SANCO), EU agencies, life style factors, internal market provisions as well as the EU Directive on patients' rights in cross-border healthcare. Among these recurring topics, expert perceptions on the establishment of DG SANCO, EU public health agencies, and successes in tobacco control were dominated by aspects of achievements. The implementation status of the Health in All Policy approach was perceived as a missed opportunity. When comparing the emerging themes from the interviews conducted with the responsibilities defined in the EU health mandate, one can identify that these responsibilities were only partly fulfilled or acknowledged by the respondents. In general, the EU is a recognized public health player in Europe which over the past two decades, has begun to develop competencies in supporting, coordinating and supplementing member state health actions. However, the assurance of health protection in other European policies seems to require further development.

  20. Twentieth anniversary of the European Union health mandate: taking stock of perceived achievements, failures and missed opportunities – a qualitative study

    PubMed Central

    2013-01-01

    Background The European Union (EU) health mandate was initially defined in the Maastricht Treaty in 1992. The twentieth anniversary of the Treaty offers a unique opportunity to take stock of EU health actions by giving an overview of influential public health related EU-level policy outputs and a summary of policy outputs or actions perceived as an achievement, a failure or a missed opportunity. Methods Semi-structured expert interviews (N = 20) were conducted focusing on EU-level actions that were relevant for health. Respondents were asked to name EU policies or actions that they perceived as an achievement, a failure or a missed opportunity. A directed content analysis approach was used to identify expert perceptions on achievements, failures and missed opportunities in the interviews. Additionally, a nominal group technique was applied to identify influential and public health relevant EU-level policy outputs. Results The ranking of influential policy outputs resulted in top positions of adjudications and legislations, agencies, European Commission (EC) programmes and strategies, official networks, cooperative structures and exchange efforts, the work on health determinants and uptake of scientific knowledge. The assessment of EU health policies as being an achievement, a failure or a missed opportunity was often characterized by diverging respondent views. Recurring topics that emerged were the Directorate General for Health and Consumers (DG SANCO), EU agencies, life style factors, internal market provisions as well as the EU Directive on patients’ rights in cross-border healthcare. Among these recurring topics, expert perceptions on the establishment of DG SANCO, EU public health agencies, and successes in tobacco control were dominated by aspects of achievements. The implementation status of the Health in All Policy approach was perceived as a missed opportunity. Conclusions When comparing the emerging themes from the interviews conducted with the responsibilities defined in the EU health mandate, one can identify that these responsibilities were only partly fulfilled or acknowledged by the respondents. In general, the EU is a recognized public health player in Europe which over the past two decades, has begun to develop competencies in supporting, coordinating and supplementing member state health actions. However, the assurance of health protection in other European policies seems to require further development. PMID:24225055

  1. Extensive antibiotic prescription rate among hospitalized patients in Uganda: but with frequent missed-dose days

    PubMed Central

    Kiguba, Ronald; Karamagi, Charles; Bird, Sheila M.

    2016-01-01

    Objectives To describe the patterns of systemic antibiotic use and missed-dose days and detail the prescription, dispensing and administration of frequently used hospital-initiated antibiotics among Ugandan inpatients. Methods This was a prospective cohort of consented adult inpatients admitted on the medical and gynaecological wards of the 1790 bed Mulago National Referral Hospital. Results Overall, 79% (603/762; 95% CI: 76%–82%) of inpatients received at least one antibiotic during hospitalization while 39% (300/762; 95% CI: 36%–43%) had used at least one antibiotic in the 4 weeks pre-admission; 1985 antibiotic DDDs, half administered parenterally, were consumed in 3741 inpatient-days. Two-fifths of inpatients who received at least one of the five frequently used hospital-initiated antibiotics (ceftriaxone, metronidazole, ciprofloxacin, amoxicillin and azithromycin) missed at least one antibiotic dose-day (44%, 243/558). The per-day risk of missed antibiotic administration was greatest on day 1: ceftriaxone (36%, 143/398), metronidazole (27%, 67/245), ciprofloxacin (34%, 39/114) and all inpatients who missed at least one dose-day of prescribed amoxicillin and azithromycin. Most patients received fewer doses than were prescribed: ceftriaxone (74%, 273/371), ciprofloxacin (90%, 94/105) and metronidazole (97%, 222/230). Of prescribed doses, only 62% of ceftriaxone doses (1178/1895), 35% of ciprofloxacin doses (396/1130) and 27% of metronidazole doses (1043/3862) were administered. Seven percent (13/188) of patients on intravenous metronidazole and 6% (5/87) on intravenous ciprofloxacin switched to oral route. Conclusions High rates of antibiotic use both pre-admission and during hospitalization were observed, with low parenteral/oral switch of hospital-initiated antibiotics. Underadministration of prescribed antibiotics was common, especially on the day of prescription, risking loss of efficacy and antibiotic resistance. PMID:26945712

  2. The impact of sociodemographic, treatment, and work support on missed work after breast cancer diagnosis

    PubMed Central

    Mujahid, Mahasin S.; Janz, Nancy K.; Hawley, Sarah T.; Griggs, Jennifer J.; Hamilton, Ann S.; Katz, Steven J.

    2016-01-01

    Work loss is a potential adverse consequence of cancer. There is limited research on patterns and correlates of paid work after diagnosis of breast cancer, especially among ethnic minorities. Women with non-metastatic breast cancer diagnosed from June 2005 to May 2006 who reported to the Los Angeles County SEER registry were identified and asked to complete the survey after initial treatment (median time from diagnosis = 8.9 months). Latina and African American women were over-sampled. Analyses were restricted to women working at the time of diagnosis, <65 years of age, and who had complete covariate information (N = 589). The outcome of the study was missed paid work (≤ month, >1 month, stopped all together). Approximately 44, 24, and 32% of women missed ≤1 month, >1 month, or stopped working, respectively. African Americans and Latinas were more likely to stop working when compared with Whites [OR for stop working vs. missed ≤1 month: 3.0, 3.4, (P < 0.001), respectively]. Women receiving mastectomy and those receiving chemotherapy were also more likely to stop working, independent of sociodemographic and treatment factors [ORs for stopped working vs. missed ≤1 month: 4.2, P < 0.001; 7.9, P < 0.001, respectively]. Not having a flexible work schedule available through work was detrimental to working [ORs for stopped working 18.9, P < 0.001 after adjusting for sociodemographic and treatment factors]. Many women stop working altogether after a diagnosis of breast cancer, particularly if they are racial/ethnic minorities, receive chemotherapy, or those who are employed in an unsupportive work settings. Health care providers need to be aware of these adverse consequences of breast cancer diagnosis and initial treatment. PMID:19360466

  3. The impact of sociodemographic, treatment, and work support on missed work after breast cancer diagnosis.

    PubMed

    Mujahid, Mahasin S; Janz, Nancy K; Hawley, Sarah T; Griggs, Jennifer J; Hamilton, Ann S; Katz, Steven J

    2010-01-01

    Work loss is a potential adverse consequence of cancer. There is limited research on patterns and correlates of paid work after diagnosis of breast cancer, especially among ethnic minorities. Women with non-metastatic breast cancer diagnosed from June 2005 to May 2006 who reported to the Los Angeles County SEER registry were identified and asked to complete the survey after initial treatment (median time from diagnosis = 8.9 months). Latina and African American women were over-sampled. Analyses were restricted to women working at the time of diagnosis, <65 years of age, and who had complete covariate information (N = 589). The outcome of the study was missed paid work (1 month, stopped all together). Approximately 44, 24, and 32% of women missed 1 month, or stopped working, respectively. African Americans and Latinas were more likely to stop working when compared with Whites [OR for stop working vs. missed

  4. Laugh Yourself into a Healthier Person: A Cross Cultural Analysis of the Effects of Varying Levels of Laughter on Health

    PubMed Central

    Hasan, Hunaid; Hasan, Tasneem Fatema

    2009-01-01

    This cross-cultural study explored along with various personality factors the relationship between laughter and disease prevalence. Previous studies have only determined the effect of laughter on various health dimensions, whereas, this study quantified the level of laughter that was beneficial or detrimental to health. There were a total of 730 participants between the ages of eighteen and thirty-nine years. 366 participants were from Aurangabad, India (AUR), and 364 participants were from Mississauga, Canada (MISS). The participants were provided a survey assessing demographics, laughter, lifestyle, subjective well-being, life satisfaction, emotional well-being and health dimensions. In AUR, a beneficial effect of laughter was mediated through moderate levels (level two) of laughter, whereas both low (level one) and high (level three) levels had no effect. Similarly, in MISS, the beneficial effect was mediated through level two, but a negative effect was also seen at level three. This could be attributable to a higher prevalence of bronchial asthma in western countries. Laughter was associated with emotional well-being in MISS and life satisfaction in AUR, providing cross cultural models to describe the interactions between laughter and disease. This study validated the correlation between emotional well-being and life satisfaction, with a stronger correlation seen in MISS, suggesting that individualists rely more on their emotional well-being to judge their life satisfaction. In conclusion, there is a benefit to clinicians to incorporate laughter history into their general medical history taking. Future research should consider developing mechanisms to explain the effects of level two, determine specific systemic effects and obtain more samples to generalize the cross cultural differences. PMID:19652724

  5. Laugh yourself into a healthier person: a cross cultural analysis of the effects of varying levels of laughter on health.

    PubMed

    Hasan, Hunaid; Hasan, Tasneem Fatema

    2009-07-28

    This cross-cultural study explored along with various personality factors the relationship between laughter and disease prevalence. Previous studies have only determined the effect of laughter on various health dimensions, whereas, this study quantified the level of laughter that was beneficial or detrimental to health. There were a total of 730 participants between the ages of eighteen and thirty-nine years. 366 participants were from Aurangabad, India (AUR), and 364 participants were from Mississauga, Canada (MISS). The participants were provided a survey assessing demographics, laughter, lifestyle, subjective well-being, life satisfaction, emotional well-being and health dimensions. In AUR, a beneficial effect of laughter was mediated through moderate levels (level two) of laughter, whereas both low (level one) and high (level three) levels had no effect. Similarly, in MISS, the beneficial effect was mediated through level two, but a negative effect was also seen at level three. This could be attributable to a higher prevalence of bronchial asthma in western countries. Laughter was associated with emotional well-being in MISS and life satisfaction in AUR, providing cross cultural models to describe the interactions between laughter and disease. This study validated the correlation between emotional well-being and life satisfaction, with a stronger correlation seen in MISS, suggesting that individualists rely more on their emotional well-being to judge their life satisfaction. In conclusion, there is a benefit to clinicians to incorporate laughter history into their general medical history taking. Future research should consider developing mechanisms to explain the effects of level two, determine specific systemic effects and obtain more samples to generalize the cross cultural differences.

  6. Standardized sign-out reduces intern perception of medical errors on the general internal medicine ward.

    PubMed

    Salerno, Stephen M; Arnett, Michael V; Domanski, Jeremy P

    2009-01-01

    Prior research on reducing variation in housestaff handoff procedures have depended on proprietary checkout software. Use of low-technology standardization techniques has not been widely studied. We wished to determine if standardizing the process of intern sign-out using low-technology sign-out tools could reduce perception of errors and missing handoff data. We conducted a pre-post prospective study of a cohort of 34 interns on a general internal medicine ward. Night interns coming off duty and day interns reassuming care were surveyed on their perception of erroneous sign-out data, mistakes made by the night intern overnight, and occurrences unanticipated by sign-out. Trainee satisfaction with the sign-out process was assessed with a 5-point Likert survey. There were 399 intern surveys performed 8 weeks before and 6 weeks after the introduction of a standardized sign-out form. The response rate was 95% for the night interns and 70% for the interns reassuming care in the morning. After the standardized form was introduced, night interns were significantly (p < .003) less likely to detect missing sign-out data including missing important diseases, contingency plans, or medications. Standardized sign-out did not significantly alter the frequency of dropped tasks or missed lab and X-ray data as perceived by the night intern. However, the day teams thought there were significantly less perceived errors on the part of the night intern (p = .001) after introduction of the standardized sign-out sheet. There was no difference in mean Likert scores of resident satisfaction with sign-out before and after the intervention. Standardized written sign-out sheets significantly improve the completeness and effectiveness of handoffs between night and day interns. Further research is needed to determine if these process improvements are related to better patient outcomes.

  7. ‘Care left undone’ during nursing shifts: associations with workload and perceived quality of care

    PubMed Central

    Ball, Jane E; Murrells, Trevor; Rafferty, Anne Marie; Morrow, Elizabeth; Griffiths, Peter

    2014-01-01

    Background There is strong evidence to show that lower nurse staffing levels in hospitals are associated with worse patient outcomes. One hypothesised mechanism is the omission of necessary nursing care caused by time pressure—‘missed care’. Aim To examine the nature and prevalence of care left undone by nurses in English National Health Service hospitals and to assess whether the number of missed care episodes is associated with nurse staffing levels and nurse ratings of the quality of nursing care and patient safety environment. Methods Cross-sectional survey of 2917 registered nurses working in 401 general medical/surgical wards in 46 general acute National Health Service hospitals in England. Results Most nurses (86%) reported that one or more care activity had been left undone due to lack of time on their last shift. Most frequently left undone were: comforting or talking with patients (66%), educating patients (52%) and developing/updating nursing care plans (47%). The number of patients per registered nurse was significantly associated with the incidence of ‘missed care’ (p<0.001). A mean of 7.8 activities per shift were left undone on wards that are rated as ‘failing’ on patient safety, compared with 2.4 where patient safety was rated as ‘excellent’ (p <0. 001). Conclusions Nurses working in English hospitals report that care is frequently left undone. Care not being delivered may be the reason low nurse staffing levels adversely affects quality and safety. Hospitals could use a nurse-rated assessment of ‘missed care’ as an early warning measure to identify wards with inadequate nurse staffing. PMID:23898215

  8. 7 CFR 51.1555 - Fairly well matured.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    .... Fairly well matured means that the skins of the potatoes are generally fairly firmly set and not more than 10 percent of the potatoes in the lot have more than one-fourth of the skin missing or “feathered.” ...

  9. Serotonin-containing neurons in basal insects: In search of ground patterns among tetraconata.

    PubMed

    Stemme, Torben; Stern, Michael; Bicker, Gerd

    2017-01-01

    The ventral nerve cord of Tetraconata contains a comparably low number of serotonin-immunoreactive neurons, facilitating individual identification of cells and their characteristic neurite morphology. This offers the rather unique possibility of establishing homologies at the single cell level. Because phylogenetic relationships within Tetraconata are still discussed controversially, comparisons of individually identifiable neurons can help to unravel these issues. Serotonin immunoreactivity has been investigated in numerous tetraconate taxa, leading to reconstructions of hypothetical ground patterns for major lineages. However, detailed descriptions of basal insects are still missing, but are crucial for meaningful evolutionary considerations. We investigated the morphology of individually identifiable serotonin-immunoreactive neurons in the ventral nerve cord of Zygentoma (Thermobia domestica, Lepisma saccharina, Atelura formicaria) and Archaeognatha (Machilis germanica, Dilta hibernica). To improve immunocytochemical resolution, we also performed preincubation experiments with 5-hydroxy-L-tryptophan and serotonin. Additionally, we checked for immunolabeling of tryptophan hydroxylase, an enzyme associated with the synthesis of serotonin. Besides the generally identified groups of anterolateral, medial, and posterolateral neurons within each ganglion of the ventral nerve cord, we identified several other immunoreactive cells, which seem to have no correspondence in other tetraconates. Furthermore, we show that not all immunoreactive neurons produce serotonin, but have the capability for serotonin uptake. Comparisons with the patterns of serotonin-containing neurons in major tetraconate taxa suggest a close phylogenetic relationship of Remipedia, Cephalocarida, and Hexapoda, supporting the Miracrustacea hypothesis. J. Comp. Neurol., 2016. © 2016 Wiley Periodicals, Inc. J. Comp. Neurol. 525:79-115, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  10. Color preference in red-green dichromats.

    PubMed

    Álvaro, Leticia; Moreira, Humberto; Lillo, Julio; Franklin, Anna

    2015-07-28

    Around 2% of males have red-green dichromacy, which is a genetic disorder of color vision where one type of cone photoreceptor is missing. Here we investigate the color preferences of dichromats. We aim (i) to establish whether the systematic and reliable color preferences of normal trichromatic observers (e.g., preference maximum at blue, minimum at yellow-green) are affected by dichromacy and (ii) to test theories of color preference with a dichromatic sample. Dichromat and normal trichromat observers named and rated how much they liked saturated, light, dark, and focal colors twice. Trichromats had the expected pattern of preference. Dichromats had a reliable pattern of preference that was different to trichromats, with a preference maximum rather than minimum at yellow and a much weaker preference for blue than trichromats. Color preference was more affected in observers who lacked the cone type sensitive to long wavelengths (protanopes) than in those who lacked the cone type sensitive to medium wavelengths (deuteranopes). Trichromats' preferences were summarized effectively in terms of cone-contrast between color and background, and yellow-blue cone-contrast could account for dichromats' pattern of preference, with some evidence for residual red-green activity in deuteranopes' preference. Dichromats' color naming also could account for their color preferences, with colors named more accurately and quickly being more preferred. This relationship between color naming and preference also was present for trichromat males but not females. Overall, the findings provide novel evidence on how dichromats experience color, advance the understanding of why humans like some colors more than others, and have implications for general theories of aesthetics.

  11. Color preference in red–green dichromats

    PubMed Central

    Álvaro, Leticia; Moreira, Humberto; Lillo, Julio; Franklin, Anna

    2015-01-01

    Around 2% of males have red–green dichromacy, which is a genetic disorder of color vision where one type of cone photoreceptor is missing. Here we investigate the color preferences of dichromats. We aim (i) to establish whether the systematic and reliable color preferences of normal trichromatic observers (e.g., preference maximum at blue, minimum at yellow-green) are affected by dichromacy and (ii) to test theories of color preference with a dichromatic sample. Dichromat and normal trichromat observers named and rated how much they liked saturated, light, dark, and focal colors twice. Trichromats had the expected pattern of preference. Dichromats had a reliable pattern of preference that was different to trichromats, with a preference maximum rather than minimum at yellow and a much weaker preference for blue than trichromats. Color preference was more affected in observers who lacked the cone type sensitive to long wavelengths (protanopes) than in those who lacked the cone type sensitive to medium wavelengths (deuteranopes). Trichromats’ preferences were summarized effectively in terms of cone-contrast between color and background, and yellow-blue cone-contrast could account for dichromats’ pattern of preference, with some evidence for residual red–green activity in deuteranopes’ preference. Dichromats’ color naming also could account for their color preferences, with colors named more accurately and quickly being more preferred. This relationship between color naming and preference also was present for trichromat males but not females. Overall, the findings provide novel evidence on how dichromats experience color, advance the understanding of why humans like some colors more than others, and have implications for general theories of aesthetics. PMID:26170287

  12. Computational synchronization of microarray data with application to Plasmodium falciparum.

    PubMed

    Zhao, Wei; Dauwels, Justin; Niles, Jacquin C; Cao, Jianshu

    2012-06-21

    Microarrays are widely used to investigate the blood stage of Plasmodium falciparum infection. Starting with synchronized cells, gene expression levels are continually measured over the 48-hour intra-erythrocytic cycle (IDC). However, the cell population gradually loses synchrony during the experiment. As a result, the microarray measurements are blurred. In this paper, we propose a generalized deconvolution approach to reconstruct the intrinsic expression pattern, and apply it to P. falciparum IDC microarray data. We develop a statistical model for the decay of synchrony among cells, and reconstruct the expression pattern through statistical inference. The proposed method can handle microarray measurements with noise and missing data. The original gene expression patterns become more apparent in the reconstructed profiles, making it easier to analyze and interpret the data. We hypothesize that reconstructed gene expression patterns represent better temporally resolved expression profiles that can be probabilistically modeled to match changes in expression level to IDC transitions. In particular, we identify transcriptionally regulated protein kinases putatively involved in regulating the P. falciparum IDC. By analyzing publicly available microarray data sets for the P. falciparum IDC, protein kinases are ranked in terms of their likelihood to be involved in regulating transitions between the ring, trophozoite and schizont developmental stages of the P. falciparum IDC. In our theoretical framework, a few protein kinases have high probability rankings, and could potentially be involved in regulating these developmental transitions. This study proposes a new methodology for extracting intrinsic expression patterns from microarray data. By applying this method to P. falciparum microarray data, several protein kinases are predicted to play a significant role in the P. falciparum IDC. Earlier experiments have indeed confirmed that several of these kinases are involved in this process. Overall, these results indicate that further functional analysis of these additional putative protein kinases may reveal new insights into how the P. falciparum IDC is regulated.

  13. The Perception of Stress Pattern in Young Cochlear Implanted Children: An EEG Study.

    PubMed

    Vavatzanidis, Niki K; Mürbe, Dirk; Friederici, Angela D; Hahne, Anja

    2016-01-01

    Children with sensorineural hearing loss may (re)gain hearing with a cochlear implant-a device that transforms sounds into electric pulses and bypasses the dysfunctioning inner ear by stimulating the auditory nerve directly with an electrode array. Many implanted children master the acquisition of spoken language successfully, yet we still have little knowledge of the actual input they receive with the implant and specifically which language sensitive cues they hear. This would be important however, both for understanding the flexibility of the auditory system when presented with stimuli after a (life-) long phase of deprivation and for planning therapeutic intervention. In rhythmic languages the general stress pattern conveys important information about word boundaries. Infant language acquisition relies on such cues and can be severely hampered when this information is missing, as seen for dyslexic children and children with specific language impairment. Here we ask whether children with a cochlear implant perceive differences in stress patterns during their language acquisition phase and if they do, whether it is present directly following implant stimulation or if and how much time is needed for the auditory system to adapt to the new sensory modality. We performed a longitudinal ERP study, testing in bimonthly intervals the stress pattern perception of 17 young hearing impaired children (age range: 9-50 months; mean: 22 months) during their first 6 months of implant use. An additional session before the implantation served as control baseline. During a session they passively listened to an oddball paradigm featuring the disyllable "baba," which was stressed either on the first or second syllable (trochaic vs. iambic stress pattern). A group of age-matched normal hearing children participated as controls. Our results show, that within the first 6 months of implant use the implanted children develop a negative mismatch response for iambic but not for trochaic deviants, thus showing the same result as the normal hearing controls. Even congenitally deaf children show the same developing pattern. We therefore conclude (a) that young implanted children have early access to stress pattern information and (b) that they develop ERP responses similar to those of normal hearing children.

  14. MISSE Scattered Atomic Oxygen Characterization Experiment

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A.; deGroh, Kim K.; Miller, Sharon K.

    2006-01-01

    An experiment designed to measure the atomic oxygen (AO) erosion profile of scattered AO was exposed to Low Earth Orbital (LEO) AO for almost four years as part of the Materials International Space Station Experiment 1 and 2 (MISSE 1 and 2). The experiment was flown in MISSE Passive Experiment Carrier 2 (PEC 2), Tray 1, attached to the exterior of the International Space Station (ISS) Quest Airlock. The experiment consisted of an aperture disk lid of Kapton H (DuPont) polyimide coated on the space exposed surface with a thin AO durable silicon dioxide film. The aperture lid had a small hole in its center to allow AO to enter into a chamber and impact a base disk of aluminum. The AO that scattered from the aluminum base could react with the under side of the aperture lid which was coated sporadically with microscopic sodium chloride particles. Scattered AO erosion can occur to materials within a spacecraft that are protected from direct AO attack but because of apertures in the spacecraft the AO can attack the interior materials after scattering. The erosion of the underside of the Kapton lid was sufficient to be able to use profilometry to measure the height of the buttes that remained after washing off the salt particles. The erosion pattern indicated that peak flux of scattered AO occurred at and angle of approximately 45 from the incoming normal incidence on the aluminum base unlike the erosion pattern predicted for scattering based on Monte Carlo computational predictions for AO scattering from Kapton H polyimide. The effective erosion yield for the scattered AO was found to be a factor of 0.214 of that for direct impingement on Kapton H polyimide.

  15. Partial entrainment of gravel bars during floods

    USGS Publications Warehouse

    Konrad, Christopher P.; Booth, Derek B.; Burges, Stephen J.; Montgomery, David R.

    2002-01-01

    Spatial patterns of bed material entrainment by floods were documented at seven gravel bars using arrays of metal washers (bed tags) placed in the streambed. The observed patterns were used to test a general stochastic model that bed material entrainment is a spatially independent, random process where the probability of entrainment is uniform over a gravel bar and a function of the peak dimensionless shear stress τ0* of the flood. The fraction of tags missing from a gravel bar during a flood, or partial entrainment, had an approximately normal distribution with respect to τ0* with a mean value (50% of the tags entrained) of 0.085 and standard deviation of 0.022 (root‐mean‐square error of 0.09). Variation in partial entrainment for a given τ0* demonstrated the effects of flow conditioning on bed strength, with lower values of partial entrainment after intermediate magnitude floods (0.065 < τ0*< 0.08) than after higher magnitude floods. Although the probability of bed material entrainment was approximately uniform over a gravel bar during individual floods and independent from flood to flood, regions of preferential stability and instability emerged at some bars over the course of a wet season. Deviations from spatially uniform and independent bed material entrainment were most pronounced for reaches with varied flow and in consecutive floods with small to intermediate magnitudes.

  16. Multiple sclerosis pathogenesis: missing pieces of an old puzzle.

    PubMed

    Rahmanzadeh, Reza; Brück, Wolfgang; Minagar, Alireza; Sahraian, Mohammad Ali

    2018-06-08

    Traditionally, multiple sclerosis (MS) was considered to be a CD4 T cell-mediated CNS autoimmunity, compatible with experimental autoimmune encephalitis model, which can be characterized by focal lesions in the white matter. However, studies of recent decades revealed several missing pieces of MS puzzle and showed that MS pathogenesis is more complex than the traditional view and may include the following: a primary degenerative process (e.g. oligodendroglial pathology), generalized abnormality of normal-appearing brain tissue, pronounced gray matter pathology, involvement of innate immunity, and CD8 T cells and B cells. Here, we review these findings and discuss their implications in MS pathogenesis.

  17. Current oral contraceptive use instructions: an analysis of patient package inserts.

    PubMed

    Williams-Deane, M; Potter, L S

    1992-01-01

    Oral contraceptive use instructions contained in manufacturers' patient package inserts (PPIs) are often inconsistent or conflicting, both among manufacturers and among different brands and regimens from the same manufacturer. Instructions on what to do about missed pills are often incomplete or inadequate, as are instructions on backup contraceptive use when pills are missed. The format of many PPIs is confusing and makes instructions difficult to find and read. Comprehending the PPIs requires the user to read at a 10th-12th-grade level, far higher than the generally accepted 5th-6th grade level considered standard for health education materials.

  18. The 50 million missing women.

    PubMed

    Allahbadia, Gautam N

    2002-09-01

    The epidemic of gender selection is ravaging countries like India & China. Approximately fifty million women are "missing" in the Indian population. Generally three principle causes are given: female infanticide, better food and health care for boys and maternal death at childbirth. Prenatal sex determination and the abortion of female fetuses threatens to skew the sex ratio to new highs. Estimates of the number of female fetuses being destroyed every year in India vary from two million to five million. This review from India attempts to summarize all the currently available methods of sex selection and also highlights the current medical practice regards the subject in south-east Asia.

  19. RHIC Abort Kicker Prefire Report

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tan, Y.; Perlstein, S.

    2014-07-07

    In an attempt to discover any pattern to prefire events, abort prefire kicker data from 2007 to the present day have been recorded. With the 2014 operations concluding, this comprises 8 years of prefire data. Any activities that the Pulsed Power Group did to decrease prefire occurrences were recorded as well, but some information may be missing. The following information is a compilation of the research to date.

  20. Epigenome-wide association study of fasting measures of glucose, insulin, and HOMA-IR in the genetics of lipid lowering drugs and diet network study

    USDA-ARS?s Scientific Manuscript database

    Known genetic susceptibility loci for type 2 diabetes (T2D) explain only a small proportion of heritable T2D risk. We hypothesize that DNA methylation patterns may contribute to variation in diabetes-related risk factors, and this epigenetic variation across the genome can contribute to the missing ...

  1. Generalized disequilibrium test for association in qualitative traits incorporating imprinting effects based on extended pedigrees.

    PubMed

    Li, Jian-Long; Wang, Peng; Fung, Wing Kam; Zhou, Ji-Yuan

    2017-10-16

    For dichotomous traits, the generalized disequilibrium test with the moment estimate of the variance (GDT-ME) is a powerful family-based association method. Genomic imprinting is an important epigenetic phenomenon and currently, there has been increasing interest of incorporating imprinting to improve the test power of association analysis. However, GDT-ME does not take imprinting effects into account, and it has not been investigated whether it can be used for association analysis when the effects indeed exist. In this article, based on a novel decomposition of the genotype score according to the paternal or maternal source of the allele, we propose the generalized disequilibrium test with imprinting (GDTI) for complete pedigrees without any missing genotypes. Then, we extend GDTI and GDT-ME to accommodate incomplete pedigrees with some pedigrees having missing genotypes, by using a Monte Carlo (MC) sampling and estimation scheme to infer missing genotypes given available genotypes in each pedigree, denoted by MCGDTI and MCGDT-ME, respectively. The proposed GDTI and MCGDTI methods evaluate the differences of the paternal as well as maternal allele scores for all discordant relative pairs in a pedigree, including beyond first-degree relative pairs. Advantages of the proposed GDTI and MCGDTI test statistics over existing methods are demonstrated by simulation studies under various simulation settings and by application to the rheumatoid arthritis dataset. Simulation results show that the proposed tests control the size well under the null hypothesis of no association, and outperform the existing methods under various imprinting effect models. The existing GDT-ME and the proposed MCGDT-ME can be used to test for association even when imprinting effects exist. For the application to the rheumatoid arthritis data, compared to the existing methods, MCGDTI identifies more loci statistically significantly associated with the disease. Under complete and incomplete imprinting effect models, our proposed GDTI and MCGDTI methods, by considering the information on imprinting effects and all discordant relative pairs within each pedigree, outperform all the existing test statistics and MCGDTI can recapture much of the missing information. Therefore, MCGDTI is recommended in practice.

  2. Using linked educational attainment data to reduce bias due to missing outcome data in estimates of the association between the duration of breastfeeding and IQ at 15 years.

    PubMed

    Cornish, Rosie P; Tilling, Kate; Boyd, Andy; Davies, Amy; Macleod, John

    2015-06-01

    Most epidemiological studies have missing information, leading to reduced power and potential bias. Estimates of exposure-outcome associations will generally be biased if the outcome variable is missing not at random (MNAR). Linkage to administrative data containing a proxy for the missing study outcome allows assessment of whether this outcome is MNAR and the evaluation of bias. We examined this in relation to the association between infant breastfeeding and IQ at 15 years, where a proxy for IQ was available through linkage to school attainment data. Subjects were those who enrolled in the Avon Longitudinal Study of Parents and Children in 1990-91 (n = 13 795), of whom 5023 had IQ measured at age 15. For those with missing IQ, 7030 (79%) had information on educational attainment at age 16 obtained through linkage to the National Pupil Database. The association between duration of breastfeeding and IQ was estimated using a complete case analysis, multiple imputation and inverse probability-of-missingness weighting; these estimates were then compared with those derived from analyses informed by the linkage. IQ at 15 was MNAR-individuals with higher attainment were less likely to have missing IQ data, even after adjusting for socio-demographic factors. All the approaches underestimated the association between breastfeeding and IQ compared with analyses informed by linkage. Linkage to administrative data containing a proxy for the outcome variable allows the MNAR assumption to be tested and more efficient analyses to be performed. Under certain circumstances, this may produce unbiased results. © The Author 2015. Published by Oxford University Press on behalf of the International Epidemiological Association.

  3. Identifying missing dictionary entries with frequency-conserving context models.

    PubMed

    Williams, Jake Ryland; Clark, Eric M; Bagrow, James P; Danforth, Christopher M; Dodds, Peter Sheridan

    2015-10-01

    In an effort to better understand meaning from natural language texts, we explore methods aimed at organizing lexical objects into contexts. A number of these methods for organization fall into a family defined by word ordering. Unlike demographic or spatial partitions of data, these collocation models are of special importance for their universal applicability. While we are interested here in text and have framed our treatment appropriately, our work is potentially applicable to other areas of research (e.g., speech, genomics, and mobility patterns) where one has ordered categorical data (e.g., sounds, genes, and locations). Our approach focuses on the phrase (whether word or larger) as the primary meaning-bearing lexical unit and object of study. To do so, we employ our previously developed framework for generating word-conserving phrase-frequency data. Upon training our model with the Wiktionary, an extensive, online, collaborative, and open-source dictionary that contains over 100000 phrasal definitions, we develop highly effective filters for the identification of meaningful, missing phrase entries. With our predictions we then engage the editorial community of the Wiktionary and propose short lists of potential missing entries for definition, developing a breakthrough, lexical extraction technique and expanding our knowledge of the defined English lexicon of phrases.

  4. A Retrospective Review of Forensic Odontology Reports Written by the Joint POW/MIA Accounting Command Central Identification Laboratory for Remains Identified from the Korean War.

    PubMed

    Shiroma, Calvin Y

    2016-01-01

    As of August 2014, the Joint POW/MIA Accounting Command has identified the remains of 1980 previously unknown U.S. service members; 280 were from the Korean War. To determine the accuracy and completeness of the available antemortem (AM) dental records, a review of the AM/postmortem (AM/PM) dental record comparisons from 233 Forensic Odontology Reports written in support of remains identified from the Korean War was performed. Seventy-two AM/PM comparisons resulted in exact dental chartings while 161 contained discrepancies which were explainable. Explainable discrepancies include undocumented treatment (103), incorrectly charted third molars as missing (82), differing opinions of specific molars present/missing (20), and erroneous treatment documentation and/or misidentification of teeth present/missing (22, other than molars). Reassessment has revealed varying levels of completeness for our available AM dental records, the need to thoroughly review our computerized comparisons, adjust our comparisons to include molar pattern variations/third molars, and updating our database comparison program. Published 2015. This article is a U.S. Government work and is in the public domain in the U.S.A.

  5. [Homicides in Rio de Janeiro, Brazil: an analysis of lethal violence].

    PubMed

    Cardoso, Francisca Letícia Miranda Gadelha; Cecchetto, Fátima Regina; Corrêa, Juliana Silva; de Souza, Tiago Oliveira

    2016-04-01

    The evolution of rates were analyzed for the following categories: murder, larceny, bodily harm followed by death, homicide for resistance to police resulting in death, policeman killed, missing persons and dead bodies found in the state and city of Rio de Janeiro and in Integrated Public Security Area 16 (AISP 16). An ecological study was conducted for the period from 2002 to 2013, using data from the Public Security Institute. To analyze the time trend and evolution of murder charges, resistance to police resulting in death and missing persons rates, Joinpoint regression was performed, using these rates as the dependent variables and the calendar year as the independent variable. For the other categories only the time trends of the rates were analyzed for the relative change in rates at the beginning and end of the period. There were falls in rates in all categories, except for missing persons. The murder rate showed a significant downward trend in the three locations. The results contributed to definition of the pattern of violence in the three locations based on the dialogue between the social sciences, public health and safety that made it possible to establish subjective and objective aspects linked to the study findings.

  6. Windowed multipole for cross section Doppler broadening

    NASA Astrophysics Data System (ADS)

    Josey, C.; Ducru, P.; Forget, B.; Smith, K.

    2016-02-01

    This paper presents an in-depth analysis on the accuracy and performance of the windowed multipole Doppler broadening method. The basic theory behind cross section data is described, along with the basic multipole formalism followed by the approximations leading to windowed multipole method and the algorithm used to efficiently evaluate Doppler broadened cross sections. The method is tested by simulating the BEAVRS benchmark with a windowed multipole library composed of 70 nuclides. Accuracy of the method is demonstrated on a single assembly case where total neutron production rates and 238U capture rates compare within 0.1% to ACE format files at the same temperature. With regards to performance, clock cycle counts and cache misses were measured for single temperature ACE table lookup and for windowed multipole. The windowed multipole method was found to require 39.6% more clock cycles to evaluate, translating to a 7.9% performance loss overall. However, the algorithm has significantly better last-level cache performance, with 3 fewer misses per evaluation, or a 65% reduction in last-level misses. This is due to the small memory footprint of the windowed multipole method and better memory access pattern of the algorithm.

  7. Multiple imputation of missing fMRI data in whole brain analysis

    PubMed Central

    Vaden, Kenneth I.; Gebregziabher, Mulugeta; Kuchinsky, Stefanie E.; Eckert, Mark A.

    2012-01-01

    Whole brain fMRI analyses rarely include the entire brain because of missing data that result from data acquisition limits and susceptibility artifact, in particular. This missing data problem is typically addressed by omitting voxels from analysis, which may exclude brain regions that are of theoretical interest and increase the potential for Type II error at cortical boundaries or Type I error when spatial thresholds are used to establish significance. Imputation could significantly expand statistical map coverage, increase power, and enhance interpretations of fMRI results. We examined multiple imputation for group level analyses of missing fMRI data using methods that leverage the spatial information in fMRI datasets for both real and simulated data. Available case analysis, neighbor replacement, and regression based imputation approaches were compared in a general linear model framework to determine the extent to which these methods quantitatively (effect size) and qualitatively (spatial coverage) increased the sensitivity of group analyses. In both real and simulated data analysis, multiple imputation provided 1) variance that was most similar to estimates for voxels with no missing data, 2) fewer false positive errors in comparison to mean replacement, and 3) fewer false negative errors in comparison to available case analysis. Compared to the standard analysis approach of omitting voxels with missing data, imputation methods increased brain coverage in this study by 35% (from 33,323 to 45,071 voxels). In addition, multiple imputation increased the size of significant clusters by 58% and number of significant clusters across statistical thresholds, compared to the standard voxel omission approach. While neighbor replacement produced similar results, we recommend multiple imputation because it uses an informed sampling distribution to deal with missing data across subjects that can include neighbor values and other predictors. Multiple imputation is anticipated to be particularly useful for 1) large fMRI data sets with inconsistent missing voxels across subjects and 2) addressing the problem of increased artifact at ultra-high field, which significantly limit the extent of whole brain coverage and interpretations of results. PMID:22500925

  8. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Goodenough, D; Olafsdottir, H; Olafsson, I

    Purpose: To automatically quantify the amount of missing tissue in a digital breast tomosynthesis system using four stair-stepped chest wall missing tissue gauges in the Tomophan™ from the Phantom Laboratory and image processing from Image Owl. Methods: The Tomophan™ phantom incorporates four stair-stepped missing tissue gauges by the chest wall, allowing measurement of missing chest wall in two different locations along the chest wall at two different heights. Each of the four gauges has 12 steps in 0.5 mm increments rising from the chest wall. An image processing algorithm was developed by Image Owl that first finds the two slicesmore » containing the steps then finds the signal through the highest step in all four gauges. Using the signal drop at the beginning of each gauge the distance to the end of the image gives the length of the missing tissue gauge in millimeters. Results: The Tomophan™ was imaged in digital breast tomosynthesis (DBT) systems from various vendors resulting in 46 cases used for testing. The results showed that on average 1.9 mm of 6 mm of the gauges are visible. A small focus group was asked to count the number of visible steps for each case which resulted in a good agreement between observer counts and computed data. Conclusion: First, the results indicate that the amount of missing chest wall can differ between vendors. Secondly it was shown that an automated method to estimate the amount of missing chest wall gauges agreed well with observer assessments. This finding indicates that consistency testing may be simplified using the Tomophan™ phantom and analysis by an automated image processing named Tomo QA. In general the reason for missing chest wall may be due to a function of the beam profile at the chest wall as DBT projects through the angular sampling. Research supported by Image Owl, Inc., The Phantom Laboratory, Inc. and Raforninn ehf; Mallozzi and Healy employed by The Phantom Laboratory, Inc.; Goodenough is a consultant to The Phantom Laboratory, Inc.; Fredriksson, Kristbjornsson, Olafsson, Oskarsdottir and Olafsdottir are employed by Raforninn, Ehf.« less

  9. Rapid iconic erasure without masking.

    PubMed

    Tijus, Charles Albert; Reeves, Adam

    2004-01-01

    We report on the erasure of the iconic memory of an array of 12 black letters flashed on a continuously- present white field. Erasure is accomplished by replacing the 16 ms letter array (frame 1) with a blank white frame for 16 ms (frame 2). The letter array returns in frame 3, with from one to six letters missing. Report of the missing letters is accurate without the blank white frame but is impoverished with it, as if interposing the blank erases the icon. Erasure occurs without any obvious luminance masking, 'mud splashes', pattern masking (backward, forward, or metacontrast), lateral masking, or masking by object substitution. Erasure is greatly decreased if the blank is presented one frame earlier or later. We speculate that erasure is due to a rapid reset of the icon produced by an informational mis-match.

  10. Multi-view non-negative tensor factorization as relation learning in healthcare data.

    PubMed

    Hang Wu; Wang, May D

    2016-08-01

    Discovering patterns in co-occurrences data between objects and groups of concepts is a useful task in many domains, such as healthcare data analysis, information retrieval, and recommender systems. These relational representations come from objects' behaviors in different views, posing a challenging task of integrating information from these views to uncover the shared latent structures. The problem is further complicated by the high dimension of data and the large ratio of missing data. We propose a new paradigm of learning semantic relations using tensor factorization, by jointly factorizing multi-view tensors and searching for a consistent underlying semantic space across each views. We formulate the idea as an optimization problem and propose efficient optimization algorithms, with a special treatment of missing data as well as high-dimensional data. Experiments results show the potential and effectiveness of our algorithms.

  11. A sensitivity analysis for missing outcomes due to truncation by death under the matched-pairs design.

    PubMed

    Imai, Kosuke; Jiang, Zhichao

    2018-04-29

    The matched-pairs design enables researchers to efficiently infer causal effects from randomized experiments. In this paper, we exploit the key feature of the matched-pairs design and develop a sensitivity analysis for missing outcomes due to truncation by death, in which the outcomes of interest (e.g., quality of life measures) are not even well defined for some units (e.g., deceased patients). Our key idea is that if 2 nearly identical observations are paired prior to the randomization of the treatment, the missingness of one unit's outcome is informative about the potential missingness of the other unit's outcome under an alternative treatment condition. We consider the average treatment effect among always-observed pairs (ATOP) whose units exhibit no missing outcome regardless of their treatment status. The naive estimator based on available pairs is unbiased for the ATOP if 2 units of the same pair are identical in terms of their missingness patterns. The proposed sensitivity analysis characterizes how the bounds of the ATOP widen as the degree of the within-pair similarity decreases. We further extend the methodology to the matched-pairs design in observational studies. Our simulation studies show that informative bounds can be obtained under some scenarios when the proportion of missing data is not too large. The proposed methodology is also applied to the randomized evaluation of the Mexican universal health insurance program. An open-source software package is available for implementing the proposed research. Copyright © 2018 John Wiley & Sons, Ltd.

  12. The CACAO Method for Smoothing, Gap Filling, and Characterizing Seasonal Anomalies in Satellite Time Series

    NASA Technical Reports Server (NTRS)

    Verger, Aleixandre; Baret, F.; Weiss, M.; Kandasamy, S.; Vermote, E.

    2013-01-01

    Consistent, continuous, and long time series of global biophysical variables derived from satellite data are required for global change research. A novel climatology fitting approach called CACAO (Consistent Adjustment of the Climatology to Actual Observations) is proposed to reduce noise and fill gaps in time series by scaling and shifting the seasonal climatological patterns to the actual observations. The shift and scale CACAO parameters adjusted for each season allow quantifying shifts in the timing of seasonal phenology and inter-annual variations in magnitude as compared to the average climatology. CACAO was assessed first over simulated daily Leaf Area Index (LAI) time series with varying fractions of missing data and noise. Then, performances were analyzed over actual satellite LAI products derived from AVHRR Long-Term Data Record for the 1981-2000 period over the BELMANIP2 globally representative sample of sites. Comparison with two widely used temporal filtering methods-the asymmetric Gaussian (AG) model and the Savitzky-Golay (SG) filter as implemented in TIMESAT-revealed that CACAO achieved better performances for smoothing AVHRR time series characterized by high level of noise and frequent missing observations. The resulting smoothed time series captures well the vegetation dynamics and shows no gaps as compared to the 50-60% of still missing data after AG or SG reconstructions. Results of simulation experiments as well as confrontation with actual AVHRR time series indicate that the proposed CACAO method is more robust to noise and missing data than AG and SG methods for phenology extraction.

  13. RADseq dataset with 90% missing data fully resolves recent radiation of Petalidium (Acanthaceae) in the ultra-arid deserts of Namibia.

    PubMed

    Tripp, Erin A; Tsai, Yi-Hsin Erica; Zhuang, Yongbin; Dexter, Kyle G

    2017-10-01

    Deserts, even those at tropical latitudes, often have strikingly low levels of plant diversity, particularly within genera. One remarkable exception to this pattern is the genus Petalidium (Acanthaceae), in which 37 of 40 named species occupy one of the driest environments on Earth, the Namib Desert of Namibia and neighboring Angola. To contribute to understanding this enigmatic diversity, we generated RADseq data for 47 accessions of Petalidium representing 22 species. We explored the impacts of 18 different combinations of assembly parameters in de novo assembly of the data across nine levels of missing data plus a best practice assembly using a reference Acanthaceae genome for a total of 171 sequence datasets assembled. RADseq data assembled at several thresholds of missing data, including 90% missing data, yielded phylogenetic hypotheses of Petalidium that were confidently and nearly fully resolved, which is notable given that divergence time analyses suggest a crown age for African species of 3.6-1.4 Ma. De novo assembly of our data yielded the most strongly supported and well-resolved topologies; in contrast, reference-based assembly performed poorly, perhaps due in part to moderate phylogenetic divergence between the reference genome, Ruellia speciosa , and the ingroup. Overall, we found that Petalidium , despite the harshness of the environment in which species occur, shows a net diversification rate (0.8-2.1 species per my) on par with those of diverse genera in tropical, Mediterranean, and alpine environments.

  14. Audio-Enhanced Tablet Computers to Assess Children’s Food Frequency From Migrant Farmworker Mothers

    PubMed Central

    Kilanowski, Jill F.; Trapl, Erika S.; Kofron, Ryan M.

    2014-01-01

    This study sought to improve data collection in children’s food frequency surveys for non-English speaking immigrant/migrant farmworker mothers using audio-enhanced tablet computers (ATCs). We hypothesized that by using technological adaptations, we would be able to improve data capture and therefore reduce lost surveys. This Food Frequency Questionnaire (FFQ), a paper-based dietary assessment tool, was adapted for ATCs and assessed consumption of 66 food items asking 3 questions for each food item: frequency, quantity of consumption, and serving size. The tablet-based survey was audio enhanced with each question “read” to participants, accompanied by food item images, together with an embedded short instructional video. Results indicated that respondents were able to complete the 198 questions from the 66 food item FFQ on ATCs in approximately 23 minutes. Compared with paper-based FFQs, ATC-based FFQs had less missing data. Despite overall reductions in missing data by use of ATCs, respondents still appeared to have difficulty with question 2 of the FFQ. Ability to score the FFQ was dependent on what sections missing data were located. Unlike the paper-based FFQs, no ATC-based FFQs were unscored due to amount or location of missing data. An ATC-based FFQ was feasible and increased ability to score this survey on children’s food patterns from migrant farmworker mothers. This adapted technology may serve as an exemplar for other non-English speaking immigrant populations. PMID:25343004

  15. A sequential coalescent algorithm for chromosomal inversions

    PubMed Central

    Peischl, S; Koch, E; Guerrero, R F; Kirkpatrick, M

    2013-01-01

    Chromosomal inversions are common in natural populations and are believed to be involved in many important evolutionary phenomena, including speciation, the evolution of sex chromosomes and local adaptation. While recent advances in sequencing and genotyping methods are leading to rapidly increasing amounts of genome-wide sequence data that reveal interesting patterns of genetic variation within inverted regions, efficient simulation methods to study these patterns are largely missing. In this work, we extend the sequential Markovian coalescent, an approximation to the coalescent with recombination, to include the effects of polymorphic inversions on patterns of recombination. Results show that our algorithm is fast, memory-efficient and accurate, making it feasible to simulate large inversions in large populations for the first time. The SMC algorithm enables studies of patterns of genetic variation (for example, linkage disequilibria) and tests of hypotheses (using simulation-based approaches) that were previously intractable. PMID:23632894

  16. Recurrent generalized tetanus: a case report.

    PubMed

    Alhaji, M A; Mustapha, M G; Ashir, G M; Akuhwa, R T; Bello, M A; Farouk, A G

    2011-04-01

    We describe recurrent generalized tetanus in a four-year-old unimmunized boy following recurrent suppurative otitis media (SOM) within an 11-month period. There are not many published reports on recurrent tetanus. We highlight the importance of both primary immunizations and the need for active immunization before discharge as the infection does not confer a lifelong immunity. The usefulness of booster doses of tetanus toxoid and missed opportunities for immunization are emphasized.

  17. Recovery of Missing Persons in Cyprus: Heavy Equipment Methods and Techniques for Complex Well Excavations.

    PubMed

    Ceker, Deren; Stevens, William D

    2015-11-01

    This technical note presents the methods and techniques developed by the Bi-communal Forensic Team (BCFT) of the Committee on Missing Persons in Cyprus (CMP) used to excavate and exhume the remains of missing persons, many of whom were buried in deep wells at sites across the island of Cyprus during the conflict period of the 1960s and 1970s. A total of 493 Turkish Cypriots and 1508 Greek Cypriots were officially reported missing by the two communities as a result of the conflict. Since the team's formation, in 2005, the BCFT has excavated 114 wells, resulting in the recovery of 195 missing individuals from 35 of these well excavations. The standard excavation approach used by the BCFT, especially for deep well recovery, consists of "ramp," "pocket," and "pool" components. These excavation features enable CMP archaeologists to excavate deep wells safely and efficiently while simultaneously permitting time for thorough documentation and unimpeded recovery of human remains. The team uses three variants of this approach to cope with the variety of geological, physical, and hydrological contexts faced in Cyprus' wells, including hard and soft landforms, the presence or absence of water, and limitations imposed by surrounding infrastructure. The "terracing", "double-ramp", and "single-ramp" variations are detailed with respect to the environmental contexts which prescribe their use. The BCFT's general procedures for human remains recovery and standard well safety protocols conclude the article. © 2015 American Academy of Forensic Sciences.

  18. Bi-level Multi-Source Learning for Heterogeneous Block-wise Missing Data

    PubMed Central

    Xiang, Shuo; Yuan, Lei; Fan, Wei; Wang, Yalin; Thompson, Paul M.; Ye, Jieping

    2013-01-01

    Bio-imaging technologies allow scientists to collect large amounts of high-dimensional data from multiple heterogeneous sources for many biomedical applications. In the study of Alzheimer's Disease (AD), neuroimaging data, gene/protein expression data, etc., are often analyzed together to improve predictive power. Joint learning from multiple complementary data sources is advantageous, but feature-pruning and data source selection are critical to learn interpretable models from high-dimensional data. Often, the data collected has block-wise missing entries. In the Alzheimer’s Disease Neuroimaging Initiative (ADNI), most subjects have MRI and genetic information, but only half have cerebrospinal fluid (CSF) measures, a different half has FDG-PET; only some have proteomic data. Here we propose how to effectively integrate information from multiple heterogeneous data sources when data is block-wise missing. We present a unified “bi-level” learning model for complete multi-source data, and extend it to incomplete data. Our major contributions are: (1) our proposed models unify feature-level and source-level analysis, including several existing feature learning approaches as special cases; (2) the model for incomplete data avoids imputing missing data and offers superior performance; it generalizes to other applications with block-wise missing data sources; (3) we present efficient optimization algorithms for modeling complete and incomplete data. We comprehensively evaluate the proposed models including all ADNI subjects with at least one of four data types at baseline: MRI, FDG-PET, CSF and proteomics. Our proposed models compare favorably with existing approaches. PMID:23988272

  19. Bi-level multi-source learning for heterogeneous block-wise missing data.

    PubMed

    Xiang, Shuo; Yuan, Lei; Fan, Wei; Wang, Yalin; Thompson, Paul M; Ye, Jieping

    2014-11-15

    Bio-imaging technologies allow scientists to collect large amounts of high-dimensional data from multiple heterogeneous sources for many biomedical applications. In the study of Alzheimer's Disease (AD), neuroimaging data, gene/protein expression data, etc., are often analyzed together to improve predictive power. Joint learning from multiple complementary data sources is advantageous, but feature-pruning and data source selection are critical to learn interpretable models from high-dimensional data. Often, the data collected has block-wise missing entries. In the Alzheimer's Disease Neuroimaging Initiative (ADNI), most subjects have MRI and genetic information, but only half have cerebrospinal fluid (CSF) measures, a different half has FDG-PET; only some have proteomic data. Here we propose how to effectively integrate information from multiple heterogeneous data sources when data is block-wise missing. We present a unified "bi-level" learning model for complete multi-source data, and extend it to incomplete data. Our major contributions are: (1) our proposed models unify feature-level and source-level analysis, including several existing feature learning approaches as special cases; (2) the model for incomplete data avoids imputing missing data and offers superior performance; it generalizes to other applications with block-wise missing data sources; (3) we present efficient optimization algorithms for modeling complete and incomplete data. We comprehensively evaluate the proposed models including all ADNI subjects with at least one of four data types at baseline: MRI, FDG-PET, CSF and proteomics. Our proposed models compare favorably with existing approaches. © 2013 Elsevier Inc. All rights reserved.

  20. Comparative Analysis of Body Radiologist to Neuroradiologist Evaluation of the Spine in Trauma Settings.

    PubMed

    Zhou, Alice L; Bonham, Luke W; Verde, Franco

    2018-05-24

    CT is routinely performed to evaluate trauma patients. When a radiologist misses an acute finding, there could be serious adverse consequences. In many subspecialty settings, body radiologists and neuroradiologists both interpret the thoracic and lumbar spine. RADPEER has estimated general disagreement rates between radiologists to be 2.9%, but the disagreement rate between neuroradiologists and body radiologists in trauma settings remains unknown. This retrospective case review examined reports from the past 10 years of adult CT scans of the chest, abdomen, and pelvis interpreted by body radiologists, with concurrent thoracic and lumbar spine reconstructions interpreted by neuroradiologists. Reports were scrutinized for disagreement on the presence of acute fractures visible to both radiologists. 1,497 report pairs were analyzed. Of them, 33 pairs (2.2%) disagreed on the presence of an unequivocal acute fracture. In scans where only one miss occurred, the body radiologist and neuroradiologist were attributed with 27 (82%) and 6 (18%) of 32 disagreements, respectively. One scan contained a miss by both the body radiologist and neuroradiologist. Transverse processes were most commonly missed, followed by vertebral body fractures. Misses by body radiologists comprised the majority of disagreements. Neuroradiologists are more sensitive for detecting spinal fractures likely secondary to experience, education, small field of view reconstructed, and more detailed reporting protocols. Additional studies are needed to determine whether emulating neuroradiology practices may help body radiologists detect subtle fractures. Copyright © 2018 American College of Radiology. Published by Elsevier Inc. All rights reserved.

  1. Multiple imputation methods for bivariate outcomes in cluster randomised trials.

    PubMed

    DiazOrdaz, K; Kenward, M G; Gomes, M; Grieve, R

    2016-09-10

    Missing observations are common in cluster randomised trials. The problem is exacerbated when modelling bivariate outcomes jointly, as the proportion of complete cases is often considerably smaller than the proportion having either of the outcomes fully observed. Approaches taken to handling such missing data include the following: complete case analysis, single-level multiple imputation that ignores the clustering, multiple imputation with a fixed effect for each cluster and multilevel multiple imputation. We contrasted the alternative approaches to handling missing data in a cost-effectiveness analysis that uses data from a cluster randomised trial to evaluate an exercise intervention for care home residents. We then conducted a simulation study to assess the performance of these approaches on bivariate continuous outcomes, in terms of confidence interval coverage and empirical bias in the estimated treatment effects. Missing-at-random clustered data scenarios were simulated following a full-factorial design. Across all the missing data mechanisms considered, the multiple imputation methods provided estimators with negligible bias, while complete case analysis resulted in biased treatment effect estimates in scenarios where the randomised treatment arm was associated with missingness. Confidence interval coverage was generally in excess of nominal levels (up to 99.8%) following fixed-effects multiple imputation and too low following single-level multiple imputation. Multilevel multiple imputation led to coverage levels of approximately 95% throughout. © 2016 The Authors. Statistics in Medicine Published by John Wiley & Sons Ltd. © 2016 The Authors. Statistics in Medicine Published by John Wiley & Sons Ltd.

  2. CHARACTERIZATION OF SMALL ESTUARIES AS A COMPONENT OF A REGIONAL-SCALE MONITORING PROGRAM

    EPA Science Inventory

    Large-scale environmental monitoring programs, such as EPA's Environmental Monitoring and Assessment Program (EMAP), by nature focus on estimating the ecological condition of large geographic areas. Generally missing is the ability to provide estimates of condition of individual ...

  3. Annual Coded Wire Tag Program; Oregon Missing Production Groups, 1995 Annual Report.

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Garrison, Robert L.; Mallette, Christine; Lewis, Mark A.

    1995-12-01

    Bonneville Power Administration is the funding source for the Oregon Department of Fish and Wildlife`s Annual Coded Wire Tag Program - Oregon Missing Production Groups Project. Tule brood fall chinook were caught primarily in the British Columbia, Washington and northern Oregon ocean commercial fisheries. The up-river bright fall chinook contributed primarily to the Alaska and British Columbia ocean commercial fisheries and the Columbia River gillnet fishery. Contribution of Rogue fall chinook released in the lower Columbia River system occurred primarily in the Oregon ocean commercial and Columbia river gillnet fisheries Willamette spring chinook salmon contributed primarily to the Alaska andmore » British Columbia ocean commercial, Oregon freshwater sport and Columbia River gillnet fisheries. Restricted ocean sport and commercial fisheries limited contribution of the Columbia coho released in the Umatilla River that survived at an average rate of 1.05% and contributed primarily to the Washington, Oregon and California ocean sport and commercial fisheries and the Columbia River gillnet fishery. The 1987 to 1991 brood years of coho released in the Yakima River survived at an average rate of 0.64% and contributed primarily to the Washington, Oregon and California ocean sport and commercial fisheries and the Columbia River gillnet fishery. Survival rates of salmon and steelhead are influenced, not only by factors in the hatchery, disease, density, diet and size and time of release, but also by environmental factors in the river and ocean. These environmental factors are controlled by large scale weather patterns such as El Nino over which man has no influence. Man could have some influence over river flow conditions, but political and economic pressures generally out weigh the biological needs of the fish.« less

  4. Dissolved organic nitrogen dynamics in the North Sea: A time series analysis (1995-2005)

    NASA Astrophysics Data System (ADS)

    Van Engeland, T.; Soetaert, K.; Knuijt, A.; Laane, R. W. P. M.; Middelburg, J. J.

    2010-09-01

    Dissolved organic nitrogen (DON) dynamics in the North Sea was explored by means of long-term time series of nitrogen parameters from the Dutch national monitoring program. Generally, the data quality was good with little missing data points. Different imputation methods were used to verify the robustness of the patterns against these missing data. No long-term trends in DON concentrations were found over the sampling period (1995-2005). Inter-annual variability in the different time series showed both common and station-specific behavior. The stations could be divided into two regions, based on absolute concentrations and the dominant times scales of variability. Average DON concentrations were 11 μmol l -1 in the coastal region and 5 μmol l -1 in the open sea. Organic fractions of total dissolved nitrogen (TDN) averaged 38 and 71% in the coastal zone and open sea, respectively, but increased over time due to decreasing dissolved inorganic nitrogen (DIN) concentrations. In both regions intra-annual variability dominated over inter-annual variability, but DON variation in the open sea was markedly shifted towards shorter time scales relative to coastal stations. In the coastal zone a consistent seasonal DON cycle existed with high values in spring-summer and low values in autumn-winter. In the open sea seasonality was weak. A marked shift in the seasonality was found at the Dogger Bank, with DON accumulation towards summer and low values in winter prior to 1999, and accumulation in spring and decline throughout summer after 1999. This study clearly shows that DON is a dynamic actor in the North Sea and should be monitored systematically to enable us to understand fully the functioning of this ecosystem.

  5. Age-Related Differences in Working Memory Performance in A 2-Back Task

    PubMed Central

    Wild-Wall, Nele; Falkenstein, Michael; Gajewski, Patrick D.

    2011-01-01

    The present study aimed to elucidate the neuro-cognitive processes underlying age-related differences in working memory. Young and middle-aged participants performed a two-choice task with low and a 2-back task with high working memory load. The P300, an event-related potential reflecting controlled stimulus–response processing in working memory, and the underlying neuronal sources of expected age-related differences were analyzed using sLORETA. Response speed was generally slower for the middle-aged than the young group. Under low working memory load the middle-aged participants traded speed for accuracy. The middle-aged were less efficient in the 2-back task as they responded slower while the error rates did not differ for groups. An age-related decline of the P300 amplitude and characteristic topographical differences were especially evident in the 2-back task. A more detailed analysis of the P300 in non-target trials revealed that amplitudes in the young but not middle-aged group differentiate between correctly detected vs. missed targets in the following trial. For these trials, source analysis revealed higher activation for the young vs. middle-aged group in brain areas which support working memory processes. The relationship between P300 and overt performance was validated by significant correlations. To sum up, under high working memory load the young group showed an increased neuronal activity before a successful detected target, while the middle-aged group showed the same neuronal pattern regardless of whether a subsequent target will be detected or missed. This stable memory trace before detected targets was reflected by a specific activation enhancement in brain areas which orchestrate maintenance, update, storage, and retrieval of information in working memory. PMID:21909328

  6. Constraining a complex biogeochemical model for CO2 and N2O emission simulations from various land uses by model-data fusion

    NASA Astrophysics Data System (ADS)

    Houska, Tobias; Kraus, David; Kiese, Ralf; Breuer, Lutz

    2017-07-01

    This study presents the results of a combined measurement and modelling strategy to analyse N2O and CO2 emissions from adjacent arable land, forest and grassland sites in Hesse, Germany. The measured emissions reveal seasonal patterns and management effects, including fertilizer application, tillage, harvest and grazing. The measured annual N2O fluxes are 4.5, 0.4 and 0.1 kg N ha-1 a-1, and the CO2 fluxes are 20.0, 12.2 and 3.0 t C ha-1 a-1 for the arable land, grassland and forest sites, respectively. An innovative model-data fusion concept based on a multicriteria evaluation (soil moisture at different depths, yield, CO2 and N2O emissions) is used to rigorously test the LandscapeDNDC biogeochemical model. The model is run in a Latin-hypercube-based uncertainty analysis framework to constrain model parameter uncertainty and derive behavioural model runs. The results indicate that the model is generally capable of predicting trace gas emissions, as evaluated with RMSE as the objective function. The model shows a reasonable performance in simulating the ecosystem C and N balances. The model-data fusion concept helps to detect remaining model errors, such as missing (e.g. freeze-thaw cycling) or incomplete model processes (e.g. respiration rates after harvest). This concept further elucidates the identification of missing model input sources (e.g. the uptake of N through shallow groundwater on grassland during the vegetation period) and uncertainty in the measured validation data (e.g. forest N2O emissions in winter months). Guidance is provided to improve the model structure and field measurements to further advance landscape-scale model predictions.

  7. [Comparison of projection radiography and computed tomography for the detection of pulmonary nodules in the dog and cat].

    PubMed

    Niesterok, C; Köhler, C; Ludewig, E; Alef, M; Oechtering, G; Kiefer, I

    2013-01-01

    The aim of our study was to evaluate the value of projection radiography as a standard screening method for the detection of lung nodules compared to computed tomography (CT). Furthermore, we attempted to describe the reasons that might lead to a failed detection of pulmonary nodules in radiography. From dogs and cats which were diagnosed in CT (multislice CT) with nodular changes in the lung pattern we selected radiographs (projection radiography with soft copy reading) in at least two projection planes produced in the same timeframe as the CT images. Exclusion criteria were nodules > 3 cm and homogenously calcified nodules (osteomata). A total of 70 animals (50 dogs and 20 cats) met the inclusion criteria. In 43 animals (61%), nodular changes had already been detected using radiography and were then confirmed by the results of the computed tomography. In detail, 32 of 50 dogs (64%) and 11 of 20 cats (55%) showed nodular lesions in the radiographs. In cats, undetected nodules were often accompanied by highly changed lung opacities, resulting in a poor contrast of the lung. In dogs the reasons for a failed detection of lung nodules were relatively equally distributed to several causes. Interestingly, small nodule size itself was not the predominant reason for missing the nodules in radiographs. In general, radiography still plays an important role as a screening method for the detection of nodular lung lesions. However, one needs to be aware, that a quite high percentage of nodular lung changes can be missed in radiographs. The overall detection rate in this study was 61%. Furthermore, we showed that plane radiographs are of poor diagnostic value when concurrent problems exist which lead to increased lung opacity.

  8. Analysis of partially observed clustered data using generalized estimating equations and multiple imputation

    PubMed Central

    Aloisio, Kathryn M.; Swanson, Sonja A.; Micali, Nadia; Field, Alison; Horton, Nicholas J.

    2015-01-01

    Clustered data arise in many settings, particularly within the social and biomedical sciences. As an example, multiple–source reports are commonly collected in child and adolescent psychiatric epidemiologic studies where researchers use various informants (e.g. parent and adolescent) to provide a holistic view of a subject’s symptomatology. Fitzmaurice et al. (1995) have described estimation of multiple source models using a standard generalized estimating equation (GEE) framework. However, these studies often have missing data due to additional stages of consent and assent required. The usual GEE is unbiased when missingness is Missing Completely at Random (MCAR) in the sense of Little and Rubin (2002). This is a strong assumption that may not be tenable. Other options such as weighted generalized estimating equations (WEEs) are computationally challenging when missingness is non–monotone. Multiple imputation is an attractive method to fit incomplete data models while only requiring the less restrictive Missing at Random (MAR) assumption. Previously estimation of partially observed clustered data was computationally challenging however recent developments in Stata have facilitated their use in practice. We demonstrate how to utilize multiple imputation in conjunction with a GEE to investigate the prevalence of disordered eating symptoms in adolescents reported by parents and adolescents as well as factors associated with concordance and prevalence. The methods are motivated by the Avon Longitudinal Study of Parents and their Children (ALSPAC), a cohort study that enrolled more than 14,000 pregnant mothers in 1991–92 and has followed the health and development of their children at regular intervals. While point estimates were fairly similar to the GEE under MCAR, the MAR model had smaller standard errors, while requiring less stringent assumptions regarding missingness. PMID:25642154

  9. SME filter approach to multiple target tracking with false and missing measurements

    NASA Astrophysics Data System (ADS)

    Lee, Yong J.; Kamen, Edward W.

    1993-10-01

    The symmetric measurement equation (SME) filter for track maintenance in multiple target tracking is extended to the general case when there are an arbitrary unknown number of false and missing position measurements in the measurement set at any time point. It is assumed that the number N of targets is known a priori and that the target motions consist of random perturbations of constant-velocity trajectories. The key idea in the paper is to generate a new measurement vector from sums-of-products of the elements of 'feasible' N-element data vectors that pass a thresholding operation in the sums-of-products framework. Via this construction, the data association problem is completely avoided, and in addition, there is no need to identify which target measurements may correspond to false returns or which target measurements may be missing. A computer simulation of SME filter performance is given, including a comparison with the associated filter (a benchmark) and the joint probabilistic data association (JPDA) filter.

  10. Inference of segmented color and texture description by tensor voting.

    PubMed

    Jia, Jiaya; Tang, Chi-Keung

    2004-06-01

    A robust synthesis method is proposed to automatically infer missing color and texture information from a damaged 2D image by (N)D tensor voting (N > 3). The same approach is generalized to range and 3D data in the presence of occlusion, missing data and noise. Our method translates texture information into an adaptive (N)D tensor, followed by a voting process that infers noniteratively the optimal color values in the (N)D texture space. A two-step method is proposed. First, we perform segmentation based on insufficient geometry, color, and texture information in the input, and extrapolate partitioning boundaries by either 2D or 3D tensor voting to generate a complete segmentation for the input. Missing colors are synthesized using (N)D tensor voting in each segment. Different feature scales in the input are automatically adapted by our tensor scale analysis. Results on a variety of difficult inputs demonstrate the effectiveness of our tensor voting approach.

  11. Search for new physics in events with photons, jets, and missing transverse energy in pp collisions at $$ \\sqrt{s}=7 $$ TeV

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Chatrchyan, S.; Khachatryan, V.; Sirunyan, A. M.

    A search for physics beyond the standard model involving events with one or more photons, jets, and missing transverse energy has been performed by the CMS experiment. The data sample corresponds to an integrated luminosity of 4.93 fb -1 of proton-proton collisions at TeV, produced at the Large Hadron Collider. No excess of events with large missing transverse energy is observed beyond expectations from standard model processes, and upper limits on the signal production cross sections for new physics processes are set at the 95% confidence level. The results of this search are interpreted in the context of three modelsmore » of new physics: a general model of gauge-mediated supersymmetry breaking, Simplified Models, and a theory involving universal extra dimensions. In the absence of evidence for new physics, exclusion regions are derived in the parameter spaces of the respective models.« less

  12. Crisis communication: learning from the 1998 LPG near miss in Stockholm.

    PubMed

    Castenfors, K; Svedin, L

    2001-12-14

    The authors examine current trends in urban risks and resilience in relation to hazardous material transports in general, and crisis communication and the Stockholm liquefied petroleum gas (LPG) near miss in 1998 in particular. The article discusses how current dynamics affecting urban areas, such as the decay in terms of increased condensation and limited expansion alternatives combined with industry site contamination and transports of hazardous materials on old worn-out physical infrastructure, work together to produce high-risk factors and increase urban vulnerability in large parts of the world today. Crisis communication takes a particularly pronounced role in the article as challenges in communication and confidence maintenance under conditions of information uncertainty and limited information control are explored. The LPG near miss case illustrates a Swedish case of urban risk and the tight coupling to hazardous material transports. The case also serves as a current example of Swedish resilience and lack of preparedness in urban crises, with particular observations and lessons learned in regards to crisis communication.

  13. How Should Genes and Taxa be Sampled for Phylogenomic Analyses with Missing Data? An Empirical Study in Iguanian Lizards.

    PubMed

    Streicher, Jeffrey W; Schulte, James A; Wiens, John J

    2016-01-01

    Targeted sequence capture is becoming a widespread tool for generating large phylogenomic data sets to address difficult phylogenetic problems. However, this methodology often generates data sets in which increasing the number of taxa and loci increases amounts of missing data. Thus, a fundamental (but still unresolved) question is whether sampling should be designed to maximize sampling of taxa or genes, or to minimize the inclusion of missing data cells. Here, we explore this question for an ancient, rapid radiation of lizards, the pleurodont iguanians. Pleurodonts include many well-known clades (e.g., anoles, basilisks, iguanas, and spiny lizards) but relationships among families have proven difficult to resolve strongly and consistently using traditional sequencing approaches. We generated up to 4921 ultraconserved elements with sampling strategies including 16, 29, and 44 taxa, from 1179 to approximately 2.4 million characters per matrix and approximately 30% to 60% total missing data. We then compared mean branch support for interfamilial relationships under these 15 different sampling strategies for both concatenated (maximum likelihood) and species tree (NJst) approaches (after showing that mean branch support appears to be related to accuracy). We found that both approaches had the highest support when including loci with up to 50% missing taxa (matrices with ~40-55% missing data overall). Thus, our results show that simply excluding all missing data may be highly problematic as the primary guiding principle for the inclusion or exclusion of taxa and genes. The optimal strategy was somewhat different for each approach, a pattern that has not been shown previously. For concatenated analyses, branch support was maximized when including many taxa (44) but fewer characters (1.1 million). For species-tree analyses, branch support was maximized with minimal taxon sampling (16) but many loci (4789 of 4921). We also show that the choice of these sampling strategies can be critically important for phylogenomic analyses, since some strategies lead to demonstrably incorrect inferences (using the same method) that have strong statistical support. Our preferred estimate provides strong support for most interfamilial relationships in this important but phylogenetically challenging group. © The Author(s) 2015. Published by Oxford University Press, on behalf of the Society of Systematic Biologists. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  14. Making Intercontinental Burning Influences Quantitative: Lessons on Transport and Geochemistry From the 3-D Simulation of CO in PEM-T A and TRACE-A

    NASA Technical Reports Server (NTRS)

    Chatfield, Robert; Houben, Howard; Sachse, Glenn; Hipskind, R. Stephen (Technical Monitor)

    1998-01-01

    We report on two aspects of the simulation of global transport of plumes originating from subtropical biomass fires. We use of meteorological assimilation (MM5) at 2-degree resolution with a Grail cloud parameterization and a Blackadar-based planetary boundary layer parameterization. Ames's GRACES model provides emissions, transport, and an appropriate level of simulated chemical transformation. We have worked with passive-tracer CO or linear chemistry. This is appropriate since we find major work to be done in evaluating CO source strengths and transport mechanisms before chemical integrations could be meaningful. First, we present mechanisms by which CO and other pollutants are introduced into the free troposphere, and are then transported with hate dilution from approx. 0 to approx. 180 degrees longitude. One principal conduit for these plumes is the vernal subtropical jet; however the plumes appear at various altitudes and latitudes as they influenced by frontal motions and (most likely) radiative processes. A common, repeated pattern of transport has pollutant plumes arriving in the distant Pacific Ocean from Africa and South America at 25 degrees south and 14 km altitude. Following this, there is then a general appearance of pollution at extending down to 5 kin at more equatorial (10 S) and polar latitudes (to 45 S). Second, we evaluate the quantitative success of our simulation. (Such success requires efforts considerably beyond trajectory analyses, and is necessary for our community to claim an understanding of the effects of biomass burning on global atmospheric chemistry and the planet's trend in oxidizing capacity.) We find that we simulate most pollution episodes sampled by Glenn Sachse's CO instrument and the Blake hydrocarbon analyses during PENT A. We will present our current ideas on why our general levels appear satisfactory when the observations are within 20 ppb of background levels, but substantially miss the variability associated with the most intense biomass burning plumes. As time allows, we will speculate on the origins of a class of plumes that appear in the mid-troposphere, but are missing from our simulations.

  15. Screening of duplicated loci reveals hidden divergence patterns in a complex salmonid genome

    USGS Publications Warehouse

    Limborg, Morten T.; Larson, Wesley; Seeb, Lisa W.; Seeb, James E.

    2017-01-01

    A whole-genome duplication (WGD) doubles the entire genomic content of a species and is thought to have catalysed adaptive radiation in some polyploid-origin lineages. However, little is known about general consequences of a WGD because gene duplicates (i.e., paralogs) are commonly filtered in genomic studies; such filtering may remove substantial portions of the genome in data sets from polyploid-origin species. We demonstrate a new method that enables genome-wide scans for signatures of selection at both nonduplicated and duplicated loci by taking locus-specific copy number into account. We apply this method to RAD sequence data from different ecotypes of a polyploid-origin salmonid (Oncorhynchus nerka) and reveal signatures of divergent selection that would have been missed if duplicated loci were filtered. We also find conserved signatures of elevated divergence at pairs of homeologous chromosomes with residual tetrasomic inheritance, suggesting that joint evolution of some nondiverged gene duplicates may affect the adaptive potential of these genes. These findings illustrate that including duplicated loci in genomic analyses enables novel insights into the evolutionary consequences of WGDs and local segmental gene duplications.

  16. Fuzzy Markov random fields versus chains for multispectral image segmentation.

    PubMed

    Salzenstein, Fabien; Collet, Christophe

    2006-11-01

    This paper deals with a comparison of recent statistical models based on fuzzy Markov random fields and chains for multispectral image segmentation. The fuzzy scheme takes into account discrete and continuous classes which model the imprecision of the hidden data. In this framework, we assume the dependence between bands and we express the general model for the covariance matrix. A fuzzy Markov chain model is developed in an unsupervised way. This method is compared with the fuzzy Markovian field model previously proposed by one of the authors. The segmentation task is processed with Bayesian tools, such as the well-known MPM (Mode of Posterior Marginals) criterion. Our goal is to compare the robustness and rapidity for both methods (fuzzy Markov fields versus fuzzy Markov chains). Indeed, such fuzzy-based procedures seem to be a good answer, e.g., for astronomical observations when the patterns present diffuse structures. Moreover, these approaches allow us to process missing data in one or several spectral bands which correspond to specific situations in astronomy. To validate both models, we perform and compare the segmentation on synthetic images and raw multispectral astronomical data.

  17. Structural Studies of Fucosylated N-Glycans by Ion Mobility Mass Spectrometry and Collision-Induced Fragmentation of Negative Ions

    NASA Astrophysics Data System (ADS)

    Harvey, David J.; Struwe, Weston B.

    2018-05-01

    There is considerable potential for the use of ion mobility mass spectrometry in structural glycobiology due in large part to the gas-phase separation attributes not typically observed by orthogonal methods. Here, we evaluate the capability of traveling wave ion mobility combined with negative ion collision-induced dissociation to provide structural information on N-linked glycans containing multiple fucose residues forming the Lewisx and Lewisy epitopes. These epitopes are involved in processes such as cell-cell recognition and are important as cancer biomarkers. Specific information that could be obtained from the intact N-glycans by negative ion CID included the general topology of the glycan such as the presence or absence of a bisecting GlcNAc residue and the branching pattern of the triantennary glycans. Information on the location of the fucose residues was also readily obtainable from ions specific to each antenna. Some isobaric fragment ions produced prior to ion mobility could subsequently be separated and, in some cases, provided additional valuable structural information that was missing from the CID spectra alone.

  18. Patient safety in external beam radiotherapy, results of the ACCIRAD project: Recommendations for radiotherapy institutions and national authorities on assessing risks and analysing adverse error-events and near misses.

    PubMed

    Malicki, Julian; Bly, Ritva; Bulot, Mireille; Godet, Jean-Luc; Jahnen, Andreas; Krengli, Marco; Maingon, Philippe; Prieto Martin, Carlos; Skrobala, Agnieszka; Valero, Marc; Jarvinen, Hannu

    2018-05-02

    The ACCIRAD project, commissioned by the European Commission (EC) to develop guidelines for risk analysis of accidental and unintended exposures in external beam radiotherapy (EBRT), was completed in the year 2014. In 2015, the "General guidelines on risk management in external beam radiotherapy" were published as EC report Radiation Protection (RP)-181. The present document is the third and final report of the findings from the ACCIRAD project. The main aim of this paper is to describe the key features of the risk management process and to provide general guidelines for radiotherapy departments and national authorities on risk assessment and analysis of adverse error-events and near misses. The recommendations provided here and in EC report RP-181 are aimed at promoting the harmonisation of risk management systems across Europe, improving patient safety, and enabling more reliable inter-country comparisons. Copyright © 2018 Elsevier B.V. All rights reserved.

  19. Multiple imputation: an application to income nonresponse in the National Survey on Recreation and the Environment

    Treesearch

    Stanley J. Zarnoch; H. Ken Cordell; Carter J. Betz; John C. Bergstrom

    2010-01-01

    Multiple imputation is used to create values for missing family income data in the National Survey on Recreation and the Environment. We present an overview of the survey and a description of the missingness pattern for family income and other key variables. We create a logistic model for the multiple imputation process and to impute data sets for family income. We...

  20. Has Teacher Education Missed out on the "Ethics Boom"? A Comparative Study of Ethics Requirements and Courses in Professional Majors of Christian Colleges and Universities

    ERIC Educational Resources Information Center

    Glanzer, Perry L.; Ream, Todd C.

    2007-01-01

    Scholars of higher education have noted an increased attention to ethics within professional disciplines such as business and journalism. This paper explores the hypothesis that the field of education has not followed that pattern. To test this hypothesis, we review our findings from a study of curricula for professional majors in 156 Christian…

  1. Missing piece of the puzzle in the science of consciousness: Resting state and endogenous correlates of consciousness.

    PubMed

    Havlík, Marek

    2017-03-01

    Consciousness still stands as one of the most interesting and the most elusive problems of neuroscience. Finding its correlates is the first step toward its satisfactory explanation. Several theories have proposed its correlates but none of them seem to be generally accepted even though most of them share some very similar elements. These elements are the activity of the thalamus, which is considered by some as the central region for consciousness, and gamma synchronization, which should be the general principal for the emergence of conscious experience. However, all of these proposed theories share one characteristic and that is that they do not take into consideration the recently discovered endogenous activity of the brain, which is generally associated with the default mode network. Although the activity of this large scale brain network is in correlation with various levels of consciousness it is still missing in discussions of consciousness. This review recognizes the importance of endogenous activity and points out the important discoveries of endogenous activity that could be an important step toward a satisfactory explanation of consciousness. Copyright © 2017 The Author. Published by Elsevier Inc. All rights reserved.

  2. Adapting to an Uncertain World: Cognitive Capacity and Causal Reasoning with Ambiguous Observations

    PubMed Central

    Shou, Yiyun; Smithson, Michael

    2015-01-01

    Ambiguous causal evidence in which the covariance of the cause and effect is partially known is pervasive in real life situations. Little is known about how people reason about causal associations with ambiguous information and the underlying cognitive mechanisms. This paper presents three experiments exploring the cognitive mechanisms of causal reasoning with ambiguous observations. Results revealed that the influence of ambiguous observations manifested by missing information on causal reasoning depended on the availability of cognitive resources, suggesting that processing ambiguous information may involve deliberative cognitive processes. Experiment 1 demonstrated that subjects did not ignore the ambiguous observations in causal reasoning. They also had a general tendency to treat the ambiguous observations as negative evidence against the causal association. Experiment 2 and Experiment 3 included a causal learning task requiring a high cognitive demand in which paired stimuli were presented to subjects sequentially. Both experiments revealed that processing ambiguous or missing observations can depend on the availability of cognitive resources. Experiment 2 suggested that the contribution of working memory capacity to the comprehensiveness of evidence retention was reduced when there were ambiguous or missing observations. Experiment 3 demonstrated that an increase in cognitive demand due to a change in the task format reduced subjects’ tendency to treat ambiguous-missing observations as negative cues. PMID:26468653

  3. Accounting for the Multiple Natures of Missing Values in Label-Free Quantitative Proteomics Data Sets to Compare Imputation Strategies.

    PubMed

    Lazar, Cosmin; Gatto, Laurent; Ferro, Myriam; Bruley, Christophe; Burger, Thomas

    2016-04-01

    Missing values are a genuine issue in label-free quantitative proteomics. Recent works have surveyed the different statistical methods to conduct imputation and have compared them on real or simulated data sets and recommended a list of missing value imputation methods for proteomics application. Although insightful, these comparisons do not account for two important facts: (i) depending on the proteomics data set, the missingness mechanism may be of different natures and (ii) each imputation method is devoted to a specific type of missingness mechanism. As a result, we believe that the question at stake is not to find the most accurate imputation method in general but instead the most appropriate one. We describe a series of comparisons that support our views: For instance, we show that a supposedly "under-performing" method (i.e., giving baseline average results), if applied at the "appropriate" time in the data-processing pipeline (before or after peptide aggregation) on a data set with the "appropriate" nature of missing values, can outperform a blindly applied, supposedly "better-performing" method (i.e., the reference method from the state-of-the-art). This leads us to formulate few practical guidelines regarding the choice and the application of an imputation method in a proteomics context.

  4. Search for supersymmetry in electroweak production with photons and large missing transverse energy in pp collisions at $$\\sqrt{s}$$ = 8 TeV

    DOE PAGES

    Khachatryan, Vardan

    2016-06-01

    Results are reported from a search for supersymmetry with gauge-mediated supersymmetry breaking in electroweak production. Final states with photons and large missing transverse energy (more » $$E_{\\mathrm{T}}^{\\text{miss}}$$) were examined. The data sample was collected in pp collisions at $$\\sqrt{s} = $$ 8 TeV with the CMS detector at the LHC and corresponds to 7.4 fb$$^{-1}$$. The analysis focuses on scenarios in which the lightest neutralino has bino- or wino-like components, resulting in decays to photons and gravitinos, where the gravitinos escape undetected. The data were obtained using a specially designed trigger with dedicated low thresholds, providing good sensitivity to signatures with photons, $$E_{\\mathrm{T}}^{\\text{miss}}$$, and low hadronic energy. No excess of events over the standard model expectation is observed. The results are interpreted using the model of general gauge mediation. With the wino mass fixed at 10 GeV above that of the bino, wino masses below 710 GeV are excluded at 95% confidence level. Lastly, constraints are also set in the context of two simplified models, for which the analysis sets the lowest cross section limits on the electroweak production of supersymmetric particles.« less

  5. On the existence, uniqueness, and asymptotic normality of a consistent solution of the likelihood equations for nonidentically distributed observations: Applications to missing data problems

    NASA Technical Reports Server (NTRS)

    Peters, C. (Principal Investigator)

    1980-01-01

    A general theorem is given which establishes the existence and uniqueness of a consistent solution of the likelihood equations given a sequence of independent random vectors whose distributions are not identical but have the same parameter set. In addition, it is shown that the consistent solution is a MLE and that it is asymptotically normal and efficient. Two applications are discussed: one in which independent observations of a normal random vector have missing components, and the other in which the parameters in a mixture from an exponential family are estimated using independent homogeneous sample blocks of different sizes.

  6. Polarization-transfer measurement to a large-virtuality bound proton in the deuteron

    NASA Astrophysics Data System (ADS)

    Yaron, I.; Izraeli, D.; Achenbach, P.; Arenhövel, H.; Beričič, J.; Böhm, R.; Bosnar, D.; Cohen, E. O.; Debenjak, L.; Distler, M. O.; Esser, A.; Friščić, I.; Gilman, R.; Korover, I.; Lichtenstadt, J.; Merkel, H.; Middleton, D. G.; Mihovilovič, M.; Müller, U.; Piasetzky, E.; Pochodzalla, J.; Ron, G.; Schlimme, B. S.; Schoth, M.; Schulz, F.; Sfienti, C.; Širca, S.; Strauch, S.; Thiel, M.; Tyukin, A.; Weber, A.; A1 Collaboration

    2017-06-01

    We report the measurement of the ratio of polarization-transfer components, Px /Pz, in the 2H (e → ,e‧ p →) n reaction at low and high missing momenta, in search of differences between free and bound protons. The observed deviation of Px /Pz from that of a free proton, which is similar to that observed in 4He, indicates that the effect in nuclei is a function of the virtuality of the knock-out proton and the missing momentum direction, but not the average nuclear density. There is a general agreement between the data and calculations, which assume free proton form factors, however, the measurements are consistently about 10% higher.

  7. Full-arch implant-retained prosthetics in general dental practice.

    PubMed

    Rosenbaum, Nigel

    2012-03-01

    The loss of all teeth from one or both dental arches is a significant disability affecting self-confidence, communication, masticatory function and aesthetics. Whilst missing teeth cannot be restored to the natural state, the development of a prosthetic dentition has been a goal of dental science throughout the centuries. Contemporary techniques allow for the replacement of missing dentition with fixed or removable solutions, solving many of the problems. Implant dentistry has transformed this area of medicine. This article provides dental practitioners with an overview of this important area of patient care. Dental practitioners in clinical practice will frequently see edentulism; a good understanding of the available options for rehabilitation is essential.

  8. The Acquisition of Tense in English

    PubMed Central

    Paradis, Johanne; Rice, Mabel L.; Crago, Martha; Marquis, Janet

    2008-01-01

    This study reports on a comparison of the use and knowledge of tense-marking morphemes in English by first language (L1), second language (L2) and specifically language-impaired (SLI) children. The objective of our research was to ascertain whether the L2 children’s tense acquisition patterns were similar or dissimilar to those of the L1 and SLI groups, and whether they would fit an (Extended) Optional Infinitive profile, or an L2-based profile, e.g., the Missing Surface Inflection Hypothesis. Results showed that the L2 children had a unique profile compared with their monolingual peers, which was better characterized by the Missing Surface Inflection Hypothesis. At the same time, results reinforce the assumption underlying the (Extended) Optional Infinitive profile that internal constraints on the acquisition of tense could be a component of L1 development, with and without SLI. PMID:18852844

  9. Data reliability in complex directed networks

    NASA Astrophysics Data System (ADS)

    Sanz, Joaquín; Cozzo, Emanuele; Moreno, Yamir

    2013-12-01

    The availability of data from many different sources and fields of science has made it possible to map out an increasing number of networks of contacts and interactions. However, quantifying how reliable these data are remains an open problem. From Biology to Sociology and Economics, the identification of false and missing positives has become a problem that calls for a solution. In this work we extend one of the newest, best performing models—due to Guimerá and Sales-Pardo in 2009—to directed networks. The new methodology is able to identify missing and spurious directed interactions with more precision than previous approaches, which renders it particularly useful for analyzing data reliability in systems like trophic webs, gene regulatory networks, communication patterns and several social systems. We also show, using real-world networks, how the method can be employed to help search for new interactions in an efficient way.

  10. Biological Diversity Research: An Analysis

    Treesearch

    James W. McMinn

    1991-01-01

    An appropriate yardstick for a biodiversity program is how it affects the persistence of viable populations. A coordinated program of biodiversity research could be structured under three overlapping subject areas: (1) threatened, endangered, and sensitive species; (2) restoration of missing, underrepresented, or declining communities; and (3) general principles and...

  11. 7 CFR 201.56-8 - Flax family, Linaceae.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...: Flax. (a) General description. (1) Germination habit: Epigeal dicot. (Due to the mucilaginous nature of... development within the test period. (4) Root system: A primary root, with secondary roots usually developing... markedly shortened, curled, or thickened. (4) Root: (i) None. (ii) Weak, stubby, or missing primary root...

  12. 7 CFR 201.56-8 - Flax family, Linaceae.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...: Flax. (a) General description. (1) Germination habit: Epigeal dicot. (Due to the mucilaginous nature of... development within the test period. (4) Root system: A primary root, with secondary roots usually developing... markedly shortened, curled, or thickened. (4) Root: (i) None. (ii) Weak, stubby, or missing primary root...

  13. Library Binding Manual. Revised Edition.

    ERIC Educational Resources Information Center

    Lakhanpal, S. K.

    This procedural manual is designed to be used in bindery sections in public, university and special libraries. It briefly discusses these general matters: administrative control; selection of a binder; when and what to bind; conventional binding; routines; missing issues; schedule for shipments; temporary binding; rare books, maps and newspapers;…

  14. Investigation of probabilistic principal component analysis compared to proper orthogonal decomposition methods for basis extraction and missing data estimation

    NASA Astrophysics Data System (ADS)

    Lee, Kyunghoon

    To evaluate the maximum likelihood estimates (MLEs) of probabilistic principal component analysis (PPCA) parameters such as a factor-loading, PPCA can invoke an expectation-maximization (EM) algorithm, yielding an EM algorithm for PPCA (EM-PCA). In order to examine the benefits of the EM-PCA for aerospace engineering applications, this thesis attempts to qualitatively and quantitatively scrutinize the EM-PCA alongside both POD and gappy POD using high-dimensional simulation data. In pursuing qualitative investigations, the theoretical relationship between POD and PPCA is transparent such that the factor-loading MLE of PPCA, evaluated by the EM-PCA, pertains to an orthogonal basis obtained by POD. By contrast, the analytical connection between gappy POD and the EM-PCA is nebulous because they distinctively approximate missing data due to their antithetical formulation perspectives: gappy POD solves a least-squares problem whereas the EM-PCA relies on the expectation of the observation probability model. To juxtapose both gappy POD and the EM-PCA, this research proposes a unifying least-squares perspective that embraces the two disparate algorithms within a generalized least-squares framework. As a result, the unifying perspective reveals that both methods address similar least-squares problems; however, their formulations contain dissimilar bases and norms. Furthermore, this research delves into the ramifications of the different bases and norms that will eventually characterize the traits of both methods. To this end, two hybrid algorithms of gappy POD and the EM-PCA are devised and compared to the original algorithms for a qualitative illustration of the different basis and norm effects. After all, a norm reflecting a curve-fitting method is found to more significantly affect estimation error reduction than a basis for two example test data sets: one is absent of data only at a single snapshot and the other misses data across all the snapshots. From a numerical performance aspect, the EM-PCA is computationally less efficient than POD for intact data since it suffers from slow convergence inherited from the EM algorithm. For incomplete data, this thesis quantitatively found that the number of data missing snapshots predetermines whether the EM-PCA or gappy POD outperforms the other because of the computational cost of a coefficient evaluation, resulting from a norm selection. For instance, gappy POD demands laborious computational effort in proportion to the number of data-missing snapshots as a consequence of the gappy norm. In contrast, the computational cost of the EM-PCA is invariant to the number of data-missing snapshots thanks to the L2 norm. In general, the higher the number of data-missing snapshots, the wider the gap between the computational cost of gappy POD and the EM-PCA. Based on the numerical experiments reported in this thesis, the following criterion is recommended regarding the selection between gappy POD and the EM-PCA for computational efficiency: gappy POD for an incomplete data set containing a few data-missing snapshots and the EM-PCA for an incomplete data set involving multiple data-missing snapshots. Last, the EM-PCA is applied to two aerospace applications in comparison to gappy POD as a proof of concept: one with an emphasis on basis extraction and the other with a focus on missing data reconstruction for a given incomplete data set with scattered missing data. The first application exploits the EM-PCA to efficiently construct reduced-order models of engine deck responses obtained by the numerical propulsion system simulation (NPSS), some of whose results are absent due to failed analyses caused by numerical instability. Model-prediction tests validate that engine performance metrics estimated by the reduced-order NPSS model exhibit considerably good agreement with those directly obtained by NPSS. Similarly, the second application illustrates that the EM-PCA is significantly more cost effective than gappy POD at repairing spurious PIV measurements obtained from acoustically-excited, bluff-body jet flow experiments. The EM-PCA reduces computational cost on factors 8 ˜ 19 compared to gappy POD while generating the same restoration results as those evaluated by gappy POD. All in all, through comprehensive theoretical and numerical investigation, this research establishes that the EM-PCA is an efficient alternative to gappy POD for an incomplete data set containing missing data over an entire data set. (Abstract shortened by UMI.)

  15. A Combinatorial Approach to Detecting Gene-Gene and Gene-Environment Interactions in Family Studies

    PubMed Central

    Lou, Xiang-Yang; Chen, Guo-Bo; Yan, Lei; Ma, Jennie Z.; Mangold, Jamie E.; Zhu, Jun; Elston, Robert C.; Li, Ming D.

    2008-01-01

    Widespread multifactor interactions present a significant challenge in determining risk factors of complex diseases. Several combinatorial approaches, such as the multifactor dimensionality reduction (MDR) method, have emerged as a promising tool for better detecting gene-gene (G × G) and gene-environment (G × E) interactions. We recently developed a general combinatorial approach, namely the generalized multifactor dimensionality reduction (GMDR) method, which can entertain both qualitative and quantitative phenotypes and allows for both discrete and continuous covariates to detect G × G and G × E interactions in a sample of unrelated individuals. In this article, we report the development of an algorithm that can be used to study G × G and G × E interactions for family-based designs, called pedigree-based GMDR (PGMDR). Compared to the available method, our proposed method has several major improvements, including allowing for covariate adjustments and being applicable to arbitrary phenotypes, arbitrary pedigree structures, and arbitrary patterns of missing marker genotypes. Our Monte Carlo simulations provide evidence that the PGMDR method is superior in performance to identify epistatic loci compared to the MDR-pedigree disequilibrium test (PDT). Finally, we applied our proposed approach to a genetic data set on tobacco dependence and found a significant interaction between two taste receptor genes (i.e., TAS2R16 and TAS2R38) in affecting nicotine dependence. PMID:18834969

  16. Predicate calculus for an architecture of multiple neural networks

    NASA Astrophysics Data System (ADS)

    Consoli, Robert H.

    1990-08-01

    Future projects with neural networks will require multiple individual network components. Current efforts along these lines are ad hoc. This paper relates the neural network to a classical device and derives a multi-part architecture from that model. Further it provides a Predicate Calculus variant for describing the location and nature of the trainings and suggests Resolution Refutation as a method for determining the performance of the system as well as the location of needed trainings for specific proofs. 2. THE NEURAL NETWORK AND A CLASSICAL DEVICE Recently investigators have been making reports about architectures of multiple neural networksL234. These efforts are appearing at an early stage in neural network investigations they are characterized by architectures suggested directly by the problem space. Touretzky and Hinton suggest an architecture for processing logical statements1 the design of this architecture arises from the syntax of a restricted class of logical expressions and exhibits syntactic limitations. In similar fashion a multiple neural netword arises out of a control problem2 from the sequence learning problem3 and from the domain of machine learning. 4 But a general theory of multiple neural devices is missing. More general attempts to relate single or multiple neural networks to classical computing devices are not common although an attempt is made to relate single neural devices to a Turing machines and Sun et a!. develop a multiple neural architecture that performs pattern classification.

  17. Common arc method for diffraction pattern orientation.

    PubMed

    Bortel, Gábor; Tegze, Miklós

    2011-11-01

    Very short pulses of X-ray free-electron lasers opened the way to obtaining diffraction signal from single particles beyond the radiation dose limit. For three-dimensional structure reconstruction many patterns are recorded in the object's unknown orientation. A method is described for the orientation of continuous diffraction patterns of non-periodic objects, utilizing intensity correlations in the curved intersections of the corresponding Ewald spheres, and hence named the common arc orientation method. The present implementation of the algorithm optionally takes into account Friedel's law, handles missing data and is capable of determining the point group of symmetric objects. Its performance is demonstrated on simulated diffraction data sets and verification of the results indicates a high orientation accuracy even at low signal levels. The common arc method fills a gap in the wide palette of orientation methods. © 2011 International Union of Crystallography

  18. ERP Correlates of Pitch Error Detection in Complex Tone and Voice Auditory Feedback with Missing Fundamental

    PubMed Central

    Behroozmand, Roozbeh; Korzyukov, Oleg; Larson, Charles R.

    2012-01-01

    Previous studies have shown that the pitch of a sound is perceived in the absence of its fundamental frequency (F0), suggesting that a distinct mechanism may resolve pitch based on a pattern that exists between harmonic frequencies. The present study investigated whether such a mechanism is active during voice pitch control. ERPs were recorded in response to +200 cents pitch shifts in the auditory feedback of self-vocalizations and complex tones with and without the F0. The absence of the fundamental induced no difference in ERP latencies. However, a right-hemisphere difference was found in the N1 amplitudes with larger responses to complex tones that included the fundamental compared to when it was missing. The P1 and N1 latencies were shorter in the left hemisphere, and the N1 and P2 amplitudes were larger bilaterally for pitch shifts in voice and complex tones compared with pure tones. These findings suggest hemispheric differences in neural encoding of pitch in sounds with missing fundamental. Data from the present study suggest that the right cortical auditory areas, thought to be specialized for spectral processing, may utilize different mechanisms to resolve pitch in sounds with missing fundamental. The left hemisphere seems to perform faster processing to resolve pitch based on the rate of temporal variations in complex sounds compared with pure tones. These effects indicate that the differential neural processing of pitch in the left and right hemispheres may enable the audio-vocal system to detect temporal and spectral variations in the auditory feedback for vocal pitch control. PMID:22386045

  19. Defining near misses: towards a sharpened definition based on empirical data about error handling processes.

    PubMed

    Kessels-Habraken, Marieke; Van der Schaaf, Tjerk; De Jonge, Jan; Rutte, Christel

    2010-05-01

    Medical errors in health care still occur frequently. Unfortunately, errors cannot be completely prevented and 100% safety can never be achieved. Therefore, in addition to error reduction strategies, health care organisations could also implement strategies that promote timely error detection and correction. Reporting and analysis of so-called near misses - usually defined as incidents without adverse consequences for patients - are necessary to gather information about successful error recovery mechanisms. This study establishes the need for a clearer and more consistent definition of near misses to enable large-scale reporting and analysis in order to obtain such information. Qualitative incident reports and interviews were collected on four units of two Dutch general hospitals. Analysis of the 143 accompanying error handling processes demonstrated that different incident types each provide unique information about error handling. Specifically, error handling processes underlying incidents that did not reach the patient differed significantly from those of incidents that reached the patient, irrespective of harm, because of successful countermeasures that had been taken after error detection. We put forward two possible definitions of near misses and argue that, from a practical point of view, the optimal definition may be contingent on organisational context. Both proposed definitions could yield large-scale reporting of near misses. Subsequent analysis could enable health care organisations to improve the safety and quality of care proactively by (1) eliminating failure factors before real accidents occur, (2) enhancing their ability to intercept errors in time, and (3) improving their safety culture. Copyright 2010 Elsevier Ltd. All rights reserved.

  20. Semi-automatic mapping of cultural heritage from airborne laser scanning using deep learning

    NASA Astrophysics Data System (ADS)

    Due Trier, Øivind; Salberg, Arnt-Børre; Holger Pilø, Lars; Tonning, Christer; Marius Johansen, Hans; Aarsten, Dagrun

    2016-04-01

    This paper proposes to use deep learning to improve semi-automatic mapping of cultural heritage from airborne laser scanning (ALS) data. Automatic detection methods, based on traditional pattern recognition, have been applied in a number of cultural heritage mapping projects in Norway for the past five years. Automatic detection of pits and heaps have been combined with visual interpretation of the ALS data for the mapping of deer hunting systems, iron production sites, grave mounds and charcoal kilns. However, the performance of the automatic detection methods varies substantially between ALS datasets. For the mapping of deer hunting systems on flat gravel and sand sediment deposits, the automatic detection results were almost perfect. However, some false detections appeared in the terrain outside of the sediment deposits. These could be explained by other pit-like landscape features, like parts of river courses, spaces between boulders, and modern terrain modifications. However, these were easy to spot during visual interpretation, and the number of missed individual pitfall traps was still low. For the mapping of grave mounds, the automatic method produced a large number of false detections, reducing the usefulness of the semi-automatic approach. The mound structure is a very common natural terrain feature, and the grave mounds are less distinct in shape than the pitfall traps. Still, applying automatic mound detection on an entire municipality did lead to a new discovery of an Iron Age grave field with more than 15 individual mounds. Automatic mound detection also proved to be useful for a detailed re-mapping of Norway's largest Iron Age grave yard, which contains almost 1000 individual graves. Combined pit and mound detection has been applied to the mapping of more than 1000 charcoal kilns that were used by an iron work 350-200 years ago. The majority of charcoal kilns were indirectly detected as either pits on the circumference, a central mound, or both. However, kilns with a flat interior and a shallow ditch along the circumference were often missed by the automatic detection method. The successfulness of automatic detection seems to depend on two factors: (1) the density of ALS ground hits on the cultural heritage structures being sought, and (2) to what extent these structures stand out from natural terrain structures. The first factor may, to some extent, be improved by using a higher number of ALS pulses per square meter. The second factor is difficult to change, and also highlights another challenge: how to make a general automatic method that is applicable in all types of terrain within a country. The mixed experience with traditional pattern recognition for semi-automatic mapping of cultural heritage led us to consider deep learning as an alternative approach. The main principle is that a general feature detector has been trained on a large image database. The feature detector is then tailored to a specific task by using a modest number of images of true and false examples of the features being sought. Results of using deep learning are compared with previous results using traditional pattern recognition.

  1. Hotspot detection using image pattern recognition based on higher-order local auto-correlation

    NASA Astrophysics Data System (ADS)

    Maeda, Shimon; Matsunawa, Tetsuaki; Ogawa, Ryuji; Ichikawa, Hirotaka; Takahata, Kazuhiro; Miyairi, Masahiro; Kotani, Toshiya; Nojima, Shigeki; Tanaka, Satoshi; Nakagawa, Kei; Saito, Tamaki; Mimotogi, Shoji; Inoue, Soichi; Nosato, Hirokazu; Sakanashi, Hidenori; Kobayashi, Takumi; Murakawa, Masahiro; Higuchi, Tetsuya; Takahashi, Eiichi; Otsu, Nobuyuki

    2011-04-01

    Below 40nm design node, systematic variation due to lithography must be taken into consideration during the early stage of design. So far, litho-aware design using lithography simulation models has been widely applied to assure that designs are printed on silicon without any error. However, the lithography simulation approach is very time consuming, and under time-to-market pressure, repetitive redesign by this approach may result in the missing of the market window. This paper proposes a fast hotspot detection support method by flexible and intelligent vision system image pattern recognition based on Higher-Order Local Autocorrelation. Our method learns the geometrical properties of the given design data without any defects as normal patterns, and automatically detects the design patterns with hotspots from the test data as abnormal patterns. The Higher-Order Local Autocorrelation method can extract features from the graphic image of design pattern, and computational cost of the extraction is constant regardless of the number of design pattern polygons. This approach can reduce turnaround time (TAT) dramatically only on 1CPU, compared with the conventional simulation-based approach, and by distributed processing, this has proven to deliver linear scalability with each additional CPU.

  2. Spatial distribution of endogenous retinoids in the murine embryonic mandible.

    PubMed

    Kronmiller, J E; Beeman, C S

    1994-12-01

    Retinoids play an important part in pattern formation during embryonic development. Exogenous retinoids alter the pattern of skeletal, neural and odontogenic tissues. Endogenous retinoids have been demonstrated previously in the murine embryonic mandible, reaching a concentration peak during the initiation of odontogenesis. It was now found that endogenous retinoids are present in a concentration gradient in the embryonic mouse mandible at the time of the initiation of the dental lamina. All-trans-retinoic acid was more concentrated in the incisor region and retinol in the molar region. These results, and the fact that exogenous retinoids produce supernumerary incisors and missing molars, suggest that all-trans-retinoic acid may instruct incisor morphology.

  3. Automated Discovery and Modeling of Sequential Patterns Preceding Events of Interest

    NASA Technical Reports Server (NTRS)

    Rohloff, Kurt

    2010-01-01

    The integration of emerging data manipulation technologies has enabled a paradigm shift in practitioners' abilities to understand and anticipate events of interest in complex systems. Example events of interest include outbreaks of socio-political violence in nation-states. Rather than relying on human-centric modeling efforts that are limited by the availability of SMEs, automated data processing technologies has enabled the development of innovative automated complex system modeling and predictive analysis technologies. We introduce one such emerging modeling technology - the sequential pattern methodology. We have applied the sequential pattern methodology to automatically identify patterns of observed behavior that precede outbreaks of socio-political violence such as riots, rebellions and coups in nation-states. The sequential pattern methodology is a groundbreaking approach to automated complex system model discovery because it generates easily interpretable patterns based on direct observations of sampled factor data for a deeper understanding of societal behaviors that is tolerant of observation noise and missing data. The discovered patterns are simple to interpret and mimic human's identifications of observed trends in temporal data. Discovered patterns also provide an automated forecasting ability: we discuss an example of using discovered patterns coupled with a rich data environment to forecast various types of socio-political violence in nation-states.

  4. Heteroassociative storage of hippocampal pattern sequences in the CA3 subregion

    PubMed Central

    Recio, Renan S.; Reyes, Marcelo B.

    2018-01-01

    Background Recent research suggests that the CA3 subregion of the hippocampus has properties of both autoassociative network, due to its ability to complete partial cues, tolerate noise, and store associations between memories, and heteroassociative one, due to its ability to store and retrieve sequences of patterns. Although there are several computational models of the CA3 as an autoassociative network, more detailed evaluations of its heteroassociative properties are missing. Methods We developed a model of the CA3 subregion containing 10,000 integrate-and-fire neurons with both recurrent excitatory and inhibitory connections, and which exhibits coupled oscillations in the gamma and theta ranges. We stored thousands of pattern sequences using a heteroassociative learning rule with competitive synaptic scaling. Results We showed that a purely heteroassociative network model can (i) retrieve pattern sequences from partial cues with external noise and incomplete connectivity, (ii) achieve homeostasis regarding the number of connections per neuron when many patterns are stored when using synaptic scaling, (iii) continuously update the set of retrievable patterns, guaranteeing that the last stored patterns can be retrieved and older ones can be forgotten. Discussion Heteroassociative networks with synaptic scaling rules seem sufficient to achieve many desirable features regarding connectivity homeostasis, pattern sequence retrieval, noise tolerance and updating of the set of retrievable patterns. PMID:29312826

  5. Graphical modeling of gene expression in monocytes suggests molecular mechanisms explaining increased atherosclerosis in smokers.

    PubMed

    Verdugo, Ricardo A; Zeller, Tanja; Rotival, Maxime; Wild, Philipp S; Münzel, Thomas; Lackner, Karl J; Weidmann, Henri; Ninio, Ewa; Trégouët, David-Alexandre; Cambien, François; Blankenberg, Stefan; Tiret, Laurence

    2013-01-01

    Smoking is a risk factor for atherosclerosis with reported widespread effects on gene expression in circulating blood cells. We hypothesized that a molecular signature mediating the relation between smoking and atherosclerosis may be found in the transcriptome of circulating monocytes. Genome-wide expression profiles and counts of atherosclerotic plaques in carotid arteries were collected in 248 smokers and 688 non-smokers from the general population. Patterns of co-expressed genes were identified by Independent Component Analysis (ICA) and network structure of the pattern-specific gene modules was inferred by the PC-algorithm. A likelihood-based causality test was implemented to select patterns that fit models containing a path "smoking→gene expression→plaques". Robustness of the causal inference was assessed by bootstrapping. At a FDR ≤0.10, 3,368 genes were associated to smoking or plaques, of which 93% were associated to smoking only. SASH1 showed the strongest association to smoking and PPARG the strongest association to plaques. Twenty-nine gene patterns were identified by ICA. Modules containing SASH1 and PPARG did not show evidence for the "smoking→gene expression→plaques" causality model. Conversely, three modules had good support for causal effects and exhibited a network topology consistent with gene expression mediating the relation between smoking and plaques. The network with the strongest support for causal effects was connected to plaques through SLC39A8, a gene with known association to HDL-cholesterol and cellular uptake of cadmium from tobacco, while smoking was directly connected to GAS6, a gene reported to have anti-inflammatory effects in atherosclerosis and to be up-regulated in the placenta of women smoking during pregnancy. Our analysis of the transcriptome of monocytes recovered genes relevant for association to smoking and atherosclerosis, and connected genes that before, were only studied in separate contexts. Inspection of correlation structure revealed candidates that would be missed by expression-phenotype association analysis alone.

  6. Graphical Modeling of Gene Expression in Monocytes Suggests Molecular Mechanisms Explaining Increased Atherosclerosis in Smokers

    PubMed Central

    Verdugo, Ricardo A.; Zeller, Tanja; Rotival, Maxime; Wild, Philipp S.; Münzel, Thomas; Lackner, Karl J.; Weidmann, Henri; Ninio, Ewa; Trégouët, David-Alexandre; Cambien, François; Blankenberg, Stefan; Tiret, Laurence

    2013-01-01

    Smoking is a risk factor for atherosclerosis with reported widespread effects on gene expression in circulating blood cells. We hypothesized that a molecular signature mediating the relation between smoking and atherosclerosis may be found in the transcriptome of circulating monocytes. Genome-wide expression profiles and counts of atherosclerotic plaques in carotid arteries were collected in 248 smokers and 688 non-smokers from the general population. Patterns of co-expressed genes were identified by Independent Component Analysis (ICA) and network structure of the pattern-specific gene modules was inferred by the PC-algorithm. A likelihood-based causality test was implemented to select patterns that fit models containing a path “smoking→gene expression→plaques”. Robustness of the causal inference was assessed by bootstrapping. At a FDR ≤0.10, 3,368 genes were associated to smoking or plaques, of which 93% were associated to smoking only. SASH1 showed the strongest association to smoking and PPARG the strongest association to plaques. Twenty-nine gene patterns were identified by ICA. Modules containing SASH1 and PPARG did not show evidence for the “smoking→gene expression→plaques” causality model. Conversely, three modules had good support for causal effects and exhibited a network topology consistent with gene expression mediating the relation between smoking and plaques. The network with the strongest support for causal effects was connected to plaques through SLC39A8, a gene with known association to HDL-cholesterol and cellular uptake of cadmium from tobacco, while smoking was directly connected to GAS6, a gene reported to have anti-inflammatory effects in atherosclerosis and to be up-regulated in the placenta of women smoking during pregnancy. Our analysis of the transcriptome of monocytes recovered genes relevant for association to smoking and atherosclerosis, and connected genes that before, were only studied in separate contexts. Inspection of correlation structure revealed candidates that would be missed by expression-phenotype association analysis alone. PMID:23372645

  7. Evaluating the granularity balance of hierarchical relationships within large biomedical terminologies towards quality improvement.

    PubMed

    Luo, Lingyun; Tong, Ling; Zhou, Xiaoxi; Mejino, Jose L V; Ouyang, Chunping; Liu, Yongbin

    2017-11-01

    Organizing the descendants of a concept under a particular semantic relationship may be rather arbitrarily carried out during the manual creation processes of large biomedical terminologies, resulting in imbalances in relationship granularity. This work aims to propose scalable models towards systematically evaluating the granularity balance of semantic relationships. We first utilize "parallel concepts set (PCS)" and two features (the length and the strength) of the paths between PCSs to design the general evaluation models, based on which we propose eight concrete evaluation models generated by two specific types of PCSs: single concept set and symmetric concepts set. We then apply those concrete models to the IS-A relationship in FMA and SNOMED CT's Body Structure subset, as well as to the Part-Of relationship in FMA. Moreover, without loss of generality, we conduct two additional rounds of applications on the Part-Of relationship after removing length redundancies and strength redundancies sequentially. At last, we perform automatic evaluation on the imbalances detected after the final round for identifying missing concepts, misaligned relations and inconsistencies. For the IS-A relationship, 34 missing concepts, 80 misalignments and 18 redundancies in FMA as well as 28 missing concepts, 114 misalignments and 1 redundancy in SNOMED CT were uncovered. In addition, 6,801 instances of imbalances for the Part-Of relationship in FMA were also identified, including 3,246 redundancies. After removing those redundancies from FMA, the total number of Part-Of imbalances was dramatically reduced to 327, including 51 missing concepts, 294 misaligned relations, and 36 inconsistencies. Manual curation performed by the FMA project leader confirmed the effectiveness of our method in identifying curation errors. In conclusion, the granularity balance of hierarchical semantic relationship is a valuable property to check for ontology quality assurance, and the scalable evaluation models proposed in this study are effective in fulfilling this task, especially in auditing relationships with sub-hierarchies, such as the seldom evaluated Part-Of relationship. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Relative efficiency of joint-model and full-conditional-specification multiple imputation when conditional models are compatible: The general location model.

    PubMed

    Seaman, Shaun R; Hughes, Rachael A

    2018-06-01

    Estimating the parameters of a regression model of interest is complicated by missing data on the variables in that model. Multiple imputation is commonly used to handle these missing data. Joint model multiple imputation and full-conditional specification multiple imputation are known to yield imputed data with the same asymptotic distribution when the conditional models of full-conditional specification are compatible with that joint model. We show that this asymptotic equivalence of imputation distributions does not imply that joint model multiple imputation and full-conditional specification multiple imputation will also yield asymptotically equally efficient inference about the parameters of the model of interest, nor that they will be equally robust to misspecification of the joint model. When the conditional models used by full-conditional specification multiple imputation are linear, logistic and multinomial regressions, these are compatible with a restricted general location joint model. We show that multiple imputation using the restricted general location joint model can be substantially more asymptotically efficient than full-conditional specification multiple imputation, but this typically requires very strong associations between variables. When associations are weaker, the efficiency gain is small. Moreover, full-conditional specification multiple imputation is shown to be potentially much more robust than joint model multiple imputation using the restricted general location model to mispecification of that model when there is substantial missingness in the outcome variable.

  9. Proteinase pattern in Trametes versicolor in response to carbon and nitrogen starvation.

    PubMed

    Staszczak, M; Nowak, G

    1984-01-01

    In stationary cultures of Trametes versicolor seven proteinase bands were revealed by electrophoresis in mycelium and five in the medium. Under conditions of nitrogen starvation the number of bands in mycelium was unchanged whereas one extracellular proteinase was missing. In the case of carbon starvation one new intracellular proteinase activity appeared and one extracellular activity disappeared. Moreover, in all starved cultures distinct differences in the intensity of particular bands were observed.

  10. Non-ignorable missingness item response theory models for choice effects in examinee-selected items.

    PubMed

    Liu, Chen-Wei; Wang, Wen-Chung

    2017-11-01

    Examinee-selected item (ESI) design, in which examinees are required to respond to a fixed number of items in a given set, always yields incomplete data (i.e., when only the selected items are answered, data are missing for the others) that are likely non-ignorable in likelihood inference. Standard item response theory (IRT) models become infeasible when ESI data are missing not at random (MNAR). To solve this problem, the authors propose a two-dimensional IRT model that posits one unidimensional IRT model for observed data and another for nominal selection patterns. The two latent variables are assumed to follow a bivariate normal distribution. In this study, the mirt freeware package was adopted to estimate parameters. The authors conduct an experiment to demonstrate that ESI data are often non-ignorable and to determine how to apply the new model to the data collected. Two follow-up simulation studies are conducted to assess the parameter recovery of the new model and the consequences for parameter estimation of ignoring MNAR data. The results of the two simulation studies indicate good parameter recovery of the new model and poor parameter recovery when non-ignorable missing data were mistakenly treated as ignorable. © 2017 The British Psychological Society.

  11. Identifying missing dictionary entries with frequency-conserving context models

    NASA Astrophysics Data System (ADS)

    Williams, Jake Ryland; Clark, Eric M.; Bagrow, James P.; Danforth, Christopher M.; Dodds, Peter Sheridan

    2015-10-01

    In an effort to better understand meaning from natural language texts, we explore methods aimed at organizing lexical objects into contexts. A number of these methods for organization fall into a family defined by word ordering. Unlike demographic or spatial partitions of data, these collocation models are of special importance for their universal applicability. While we are interested here in text and have framed our treatment appropriately, our work is potentially applicable to other areas of research (e.g., speech, genomics, and mobility patterns) where one has ordered categorical data (e.g., sounds, genes, and locations). Our approach focuses on the phrase (whether word or larger) as the primary meaning-bearing lexical unit and object of study. To do so, we employ our previously developed framework for generating word-conserving phrase-frequency data. Upon training our model with the Wiktionary, an extensive, online, collaborative, and open-source dictionary that contains over 100 000 phrasal definitions, we develop highly effective filters for the identification of meaningful, missing phrase entries. With our predictions we then engage the editorial community of the Wiktionary and propose short lists of potential missing entries for definition, developing a breakthrough, lexical extraction technique and expanding our knowledge of the defined English lexicon of phrases.

  12. Upper Extremity Functional Status of Female Youth Softball Pitchers Using the Kerlan-Jobe Orthopaedic Clinic Questionnaire.

    PubMed

    Holtz, Kaila A; O'Connor, Russell J

    2018-01-01

    Softball is a popular sport with a high incidence of upper extremity injuries. The Kerlan-Jobe Orthopaedic Clinic (KJOC) questionnaire is a validated performance and functional assessment tool used in overhead athletes. Upper extremity pain patterns and baseline KJOC scores have not been reported for active female youth softball pitchers. The purpose of this study was to establish the prevalence of upper extremity pain and its effect in female youth softball pitchers over a competitive season. We hypothesized that participants who missed time due to injury in the past year would have lower KJOC scores. Cross-sectional study; Level of evidence, 3. Fifty-three female softball pitchers aged 12 to 18 years were recruited from softball clinics in Vancouver, British Columbia, Canada. All participants self-identified as a pitcher on a competitive travel team. Participants were administered the KJOC questionnaire before and during the playing season. Missed time due to injury in the past year, current pain patterns, and KJOC scores were primary outcomes. The mean (±SD) preseason KJOC score was 87.2 ± 10.6. In the preseason, 22.6% of pitchers reported playing with arm trouble, and 32.1% missed time due to injury in the past year. The mean KJOC score for pitchers reporting a previous injury (n = 17) was significantly lower compared with those without an injury (n = 36) (79.5 ± 13.8 vs 90.9 ± 6.2, respectively; P = .02). The posterior shoulder was the most commonly reported pain location. For the cohort completing the questionnaire both before and during the playing season (n = 35), mean KJOC scores did not change significantly over the playing season ( P = .64). Lower preseason KJOC scores were significantly related to the in-season injury risk ( P = .016). Pitchers with a preseason score of less than 90 had a 3.5 (95% CI, 1.1-11.2) times greater risk of reporting an in-season injury. Female youth softball pitchers have a high baseline functional status. However, 1 in 3 pitchers reported missed time due to injury in the previous year, and shoulder pain was more prevalent than elbow pain. The KJOC questionnaire can be used by coaches, researchers, and clinicians to identify youth softball pitchers at risk for injuries who may benefit from interventions.

  13. Upper Extremity Functional Status of Female Youth Softball Pitchers Using the Kerlan-Jobe Orthopaedic Clinic Questionnaire

    PubMed Central

    Holtz, Kaila A.; O’Connor, Russell J.

    2018-01-01

    Background: Softball is a popular sport with a high incidence of upper extremity injuries. The Kerlan-Jobe Orthopaedic Clinic (KJOC) questionnaire is a validated performance and functional assessment tool used in overhead athletes. Upper extremity pain patterns and baseline KJOC scores have not been reported for active female youth softball pitchers. Purpose/Hypothesis: The purpose of this study was to establish the prevalence of upper extremity pain and its effect in female youth softball pitchers over a competitive season. We hypothesized that participants who missed time due to injury in the past year would have lower KJOC scores. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Fifty-three female softball pitchers aged 12 to 18 years were recruited from softball clinics in Vancouver, British Columbia, Canada. All participants self-identified as a pitcher on a competitive travel team. Participants were administered the KJOC questionnaire before and during the playing season. Missed time due to injury in the past year, current pain patterns, and KJOC scores were primary outcomes. Results: The mean (±SD) preseason KJOC score was 87.2 ± 10.6. In the preseason, 22.6% of pitchers reported playing with arm trouble, and 32.1% missed time due to injury in the past year. The mean KJOC score for pitchers reporting a previous injury (n = 17) was significantly lower compared with those without an injury (n = 36) (79.5 ± 13.8 vs 90.9 ± 6.2, respectively; P = .02). The posterior shoulder was the most commonly reported pain location. For the cohort completing the questionnaire both before and during the playing season (n = 35), mean KJOC scores did not change significantly over the playing season (P = .64). Lower preseason KJOC scores were significantly related to the in-season injury risk (P = .016). Pitchers with a preseason score of less than 90 had a 3.5 (95% CI, 1.1-11.2) times greater risk of reporting an in-season injury. Conclusion: Female youth softball pitchers have a high baseline functional status. However, 1 in 3 pitchers reported missed time due to injury in the previous year, and shoulder pain was more prevalent than elbow pain. The KJOC questionnaire can be used by coaches, researchers, and clinicians to identify youth softball pitchers at risk for injuries who may benefit from interventions. PMID:29349094

  14. Latent Patient Cluster Discovery for Robust Future Forecasting and New-Patient Generalization.

    PubMed

    Qian, Ting; Masino, Aaron J

    2016-01-01

    Commonly referred to as predictive modeling, the use of machine learning and statistical methods to improve healthcare outcomes has recently gained traction in biomedical informatics research. Given the vast opportunities enabled by large Electronic Health Records (EHR) data and powerful resources for conducting predictive modeling, we argue that it is yet crucial to first carefully examine the prediction task and then choose predictive methods accordingly. Specifically, we argue that there are at least three distinct prediction tasks that are often conflated in biomedical research: 1) data imputation, where a model fills in the missing values in a dataset, 2) future forecasting, where a model projects the development of a medical condition for a known patient based on existing observations, and 3) new-patient generalization, where a model transfers the knowledge learned from previously observed patients to newly encountered ones. Importantly, the latter two tasks-future forecasting and new-patient generalizations-tend to be more difficult than data imputation as they require predictions to be made on potentially out-of-sample data (i.e., data following a different predictable pattern from what has been learned by the model). Using hearing loss progression as an example, we investigate three regression models and show that the modeling of latent clusters is a robust method for addressing the more challenging prediction scenarios. Overall, our findings suggest that there exist significant differences between various kinds of prediction tasks and that it is important to evaluate the merits of a predictive model relative to the specific purpose of a prediction task.

  15. Defining Weapons of Mass Destruction

    DTIC Science & Technology

    2012-01-01

    physicist Merle Tuve. “Even the atomic bomb didn’t bother him as much as jellied gasoline [napalm].”155 Indeed, it is clear that weapons generally...The official toll was 42,600 dead, not including 2,000 missing. However, the official Royal Air Force history of the bombing campaign suggests that the

  16. Laboratory evaluation of dual-frequency multisensor capacitance probes to monitor soil water and salinity

    USDA-ARS?s Scientific Manuscript database

    Real-time information on salinity levels and transport of fertilizers are generally missing from soil profile knowledge bases. A dual-frequency multisensor capacitance probe (MCP) is now commercially available for sandy soils that simultaneously monitor volumetric soil water content (VWC, ') and sa...

  17. Flight Technical Error for Category B Non-Precision Approaches and Missed Approaches Using Non-Differential GPS for Course Guidance

    DOT National Transportation Integrated Search

    1993-11-01

    Twelve general aviation pilots flew a Beechcraft Baron on 93 non-precision instrument approaches using a nondifferential : GPS receiver nodifled to satisfy selected functional requirements specified in TS0-C129. : The purposes of the effort were to d...

  18. Can Mentoring Assist in the School-to-Work Transition?

    ERIC Educational Resources Information Center

    Lang, Martin

    2010-01-01

    Purpose: Due to recent bottlenecks in the apprenticeship market the transition from general schooling into the German employment system has become more and more problematic for many pupils over the past years. In particular, young persons with migrant backgrounds, low academic achievement or missing school graduations need special help from…

  19. 12 CFR 1281.12 - General counting requirements.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... denominator shall be calculated for purchase money mortgages and for refinancing mortgages. (b) Missing data or information for the housing goals. (1) When a Bank lacks sufficient data or information to... year; a sampling of such purchases is not acceptable. (f) Newly available data. When a Bank uses data...

  20. 12 CFR 1281.12 - General counting requirements.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... denominator shall be calculated for purchase money mortgages and for refinancing mortgages. (b) Missing data or information for the housing goals.—(1) When a Bank lacks sufficient data or information to... year; a sampling of such purchases is not acceptable. (f) Newly available data. When a Bank uses data...

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