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Sample records for account potential confounders

  1. Assessing Sensitivity to Unmeasured Confounding Using a Simulated Potential Confounder

    ERIC Educational Resources Information Center

    Carnegie, Nicole Bohme; Harada, Masataka; Hill, Jennifer L.

    2016-01-01

    A major obstacle to developing evidenced-based policy is the difficulty of implementing randomized experiments to answer all causal questions of interest. When using a nonexperimental study, it is critical to assess how much the results could be affected by unmeasured confounding. We present a set of graphical and numeric tools to explore the…

  2. Reporting phenotypes in mouse models when considering body size as a potential confounder.

    PubMed

    Oellrich, Anika; Meehan, Terrence F; Parkinson, Helen; Sarntivijai, Sirarat; White, Jacqueline K; Karp, Natasha A

    2016-01-01

    Genotype-phenotype studies aim to identify causative relationships between genes and phenotypes. The International Mouse Phenotyping Consortium is a high throughput phenotyping program whose goal is to collect phenotype data for a knockout mouse strain of every protein coding gene. The scale of the project requires an automatic analysis pipeline to detect abnormal phenotypes, and disseminate the resulting gene-phenotype annotation data into public resources. A body weight phenotype is a common result of knockout studies. As body weight correlates with many other biological traits, this challenges the interpretation of related gene-phenotype associations. Co-correlation can lead to gene-phenotype associations that are potentially misleading. Here we use statistical modelling to account for body weight as a potential confounder to assess the impact. We find that there is a considerable impact on previously established gene-phenotype associations due to an increase in sensitivity as well as the confounding effect. We investigated the existing ontologies to represent this phenotypic information and we explored ways to ontologically represent the results of the influence of confounders on gene-phenotype associations. With the scale of data being disseminated within the high throughput programs and the range of downstream studies that utilise these data, it is critical to consider how we improve the quality of the disseminated data and provide a robust ontological representation.

  3. A method for assessing the potential for confounding applied to ionic strength in central Appalachian streams.

    PubMed

    Suter, Glenn W; Cormier, Susan M

    2013-02-01

    Causal relationships derived from field data are potentially confounded by variables that are correlated with both the cause and its effect. The present study presents a method for assessing the potential for confounding and applies it to the relationship between ionic strength and impairment of benthic invertebrate assemblages in central Appalachian streams. The method weighs all available evidence for and against confounding by each potential confounder. It identifies 10 types of evidence for confounding, presents a qualitative scoring system, and provides rules for applying the scores. Twelve potential confounders were evaluated: habitat, organic enrichment, nutrients, deposited sediments, pH, selenium, temperature, lack of headwaters, catchment area, settling ponds, dissolved oxygen, and metals. One potential confounder, low pH, was found to be biologically significant and eliminated by removing sites with pH < 6. Other potential confounders were eliminated based on the weight of evidence. This method was found to be useful and defensible. It could be applied to other environmental assessments that use field data to develop causal relationships, including contaminated site remediation or management of natural resources.

  4. Event-related potential indices of congruency sequence effects without feature integration or contingency learning confounds.

    PubMed

    Larson, Michael J; Clayson, Peter E; Kirwan, C Brock; Weissman, Daniel H

    2016-06-01

    The congruency effect in Stroop-like tasks (i.e., increased response time and reduced accuracy in incongruent relative to congruent trials) is often smaller when the previous trial was incongruent as compared to congruent. This congruency sequence effect (CSE) is thought to reflect cognitive control processes that shift attention to the target and/or modulate the response engendered by the distracter differently after incongruent relative to congruent trials. The neural signatures of CSEs are therefore usually attributed to cognitive control processes that minimize distraction from irrelevant stimuli. However, CSEs in previous functional neuroimaging studies were ubiquitously confounded with feature integration and/or contingency learning processes. We therefore investigated whether a neural CSE can be observed without such confounds in a group of healthy young adults (n = 56). To this end, we combined a prime-probe task that lacks such confounds with high-density ERPs to identify, for the first time, the neural time course of confound-minimized CSEs. Replicating recent behavioral findings, we observed strong CSEs in this task for mean response time and mean accuracy. Critically, conceptually replicating prior ERP results from confounded tasks, we also observed a CSE in both the parietal conflict slow potential (conflict SP) and the frontomedial N450. These findings indicate for the first time that neural CSEs as indexed by ERPs can be observed without the typical confounds. More broadly, the present study provides a confound-minimized protocol that will help future researchers to better isolate the neural bases of control processes that minimize distraction from irrelevant stimuli. PMID:26854028

  5. Accounting for uncertainty in confounder and effect modifier selection when estimating average causal effects in generalized linear models.

    PubMed

    Wang, Chi; Dominici, Francesca; Parmigiani, Giovanni; Zigler, Corwin Matthew

    2015-09-01

    Confounder selection and adjustment are essential elements of assessing the causal effect of an exposure or treatment in observational studies. Building upon work by Wang et al. (2012, Biometrics 68, 661-671) and Lefebvre et al. (2014, Statistics in Medicine 33, 2797-2813), we propose and evaluate a Bayesian method to estimate average causal effects in studies with a large number of potential confounders, relatively few observations, likely interactions between confounders and the exposure of interest, and uncertainty on which confounders and interaction terms should be included. Our method is applicable across all exposures and outcomes that can be handled through generalized linear models. In this general setting, estimation of the average causal effect is different from estimation of the exposure coefficient in the outcome model due to noncollapsibility. We implement a Bayesian bootstrap procedure to integrate over the distribution of potential confounders and to estimate the causal effect. Our method permits estimation of both the overall population causal effect and effects in specified subpopulations, providing clear characterization of heterogeneous exposure effects that may vary considerably across different covariate profiles. Simulation studies demonstrate that the proposed method performs well in small sample size situations with 100-150 observations and 50 covariates. The method is applied to data on 15,060 US Medicare beneficiaries diagnosed with a malignant brain tumor between 2000 and 2009 to evaluate whether surgery reduces hospital readmissions within 30 days of diagnosis.

  6. Accounting for Uncertainty in Confounder and Effect Modifier Selection when Estimating Average Causal Effects in Generalized Linear Models

    PubMed Central

    Wang, Chi; Dominici, Francesca; Parmigiani, Giovanni; Zigler, Corwin Matthew

    2015-01-01

    Summary Confounder selection and adjustment are essential elements of assessing the causal effect of an exposure or treatment in observational studies. Building upon work by Wang et al. (2012) and Lefebvre et al. (2014), we propose and evaluate a Bayesian method to estimate average causal effects in studies with a large number of potential confounders, relatively few observations, likely interactions between confounders and the exposure of interest, and uncertainty on which confounders and interaction terms should be included. Our method is applicable across all exposures and outcomes that can be handled through generalized linear models. In this general setting, estimation of the average causal effect is different from estimation of the exposure coefficient in the outcome model due to non-collapsibility. We implement a Bayesian bootstrap procedure to integrate over the distribution of potential confounders and to estimate the causal effect. Our method permits estimation of both the overall population causal effect and effects in specified subpopulations, providing clear characterization of heterogeneous exposure effects that may vary considerably across different covariate profiles. Simulation studies demonstrate that the proposed method performs well in small sample size situations with 100 to 150 observations and 50 covariates. The method is applied to data on 15060 US Medicare beneficiaries diagnosed with a malignant brain tumor between 2000 and 2009 to evaluate whether surgery reduces hospital readmissions within thirty days of diagnosis. PMID:25899155

  7. Bounds on potential risks and causal risk differences under assumptions about confounding parameters.

    PubMed

    Chiba, Yasutaka; Sato, Tosiya; Greenland, Sander

    2007-12-10

    Nonparametric bounds on causal effects in observational studies are available under deterministic potential-outcome models. We derive narrower bounds by adding assumptions regarding bias due to confounding. This bias is defined as the difference between the expectation of potential outcomes for the exposed group and that for the unexposed group. We show that crude effect measures bound causal effects under the given assumptions. We then derive bounds for randomized studies with noncompliance, which are given by the per protocol effect. With perfect compliance in one treatment group, the direction of effect becomes identifiable under our assumptions. Although the assumptions are not themselves identifiable, they are nonetheless reasonable in some situations.

  8. Interpersonal discrimination and depressive symptomatology: examination of several personality-related characteristics as potential confounders in a racial/ethnic heterogeneous adult sample

    PubMed Central

    2013-01-01

    Background Research suggests that reports of interpersonal discrimination result in poor mental health. Because personality characteristics may either confound or mediate the link between these reports and mental health, there is a need to disentangle its role in order to better understand the nature of discrimination-mental health association. We examined whether hostility, anger repression and expression, pessimism, optimism, and self-esteem served as confounders in the association between perceived interpersonal discrimination and CESD-based depressive symptoms in a race/ethnic heterogeneous probability-based sample of community-dwelling adults. Methods We employed a series of ordinary least squares regression analyses to examine the potential confounding effect of hostility, anger repression and expression, pessimism, optimism, and self-esteem between interpersonal discrimination and depressive symptoms. Results Hostility, anger repression, pessimism and self-esteem were significant as possible confounders of the relationship between interpersonal discrimination and depressive symptoms, together accounting for approximately 38% of the total association (beta: 0.1892, p < 0.001). However, interpersonal discrimination remained a positive predictor of depressive symptoms (beta: 0.1176, p < 0.001). Conclusion As one of the first empirical attempts to examine the potential confounding role of personality characteristics in the association between reports of interpersonal discrimination and mental health, our results suggest that personality-related characteristics may serve as potential confounders. Nevertheless, our results also suggest that, net of these characteristics, reports of interpersonal discrimination are associated with poor mental health. PMID:24256578

  9. The effect of clozapine on premature mortality: an assessment of clinical monitoring and other potential confounders.

    PubMed

    Hayes, Richard D; Downs, Johnny; Chang, Chin-Kuo; Jackson, Richard G; Shetty, Hitesh; Broadbent, Matthew; Hotopf, Matthew; Stewart, Robert

    2015-05-01

    Clozapine can cause severe adverse effects yet it is associated with reduced mortality risk. We test the hypothesis this association is due to increased clinical monitoring and investigate risk of premature mortality from natural causes. We identified 14 754 individuals (879 deaths) with serious mental illness (SMI) including schizophrenia, schizoaffective and bipolar disorders aged ≥ 15 years in a large specialist mental healthcare case register linked to national mortality tracing. In this cohort study we modeled the effect of clozapine on mortality over a 5-year period (2007-2011) using Cox regression. Individuals prescribed clozapine had more severe psychopathology and poorer functional status. Many of the exposures associated with clozapine use were themselves risk factors for increased mortality. However, we identified a strong association between being prescribed clozapine and lower mortality which persisted after controlling for a broad range of potential confounders including clinical monitoring and markers of disease severity (adjusted hazard ratio 0.4; 95% CI 0.2-0.7; p = .001). This association remained after restricting the sample to those with a diagnosis of schizophrenia or those taking antipsychotics and after using propensity scores to reduce the impact of confounding by indication. Among individuals with SMI, those prescribed clozapine had a reduced risk of mortality due to both natural and unnatural causes. We found no evidence to indicate that lower mortality associated with clozapine in SMI was due to increased clinical monitoring or confounding factors. This is the first study to report an association between clozapine and reduced risk of mortality from natural causes. PMID:25154620

  10. The Effect of Clozapine on Premature Mortality: An Assessment of Clinical Monitoring and Other Potential Confounders

    PubMed Central

    Hayes, Richard D.; Downs, Johnny; Chang, Chin-Kuo; Jackson, Richard G.; Shetty, Hitesh; Broadbent, Matthew; Hotopf, Matthew; Stewart, Robert

    2015-01-01

    Clozapine can cause severe adverse effects yet it is associated with reduced mortality risk. We test the hypothesis this association is due to increased clinical monitoring and investigate risk of premature mortality from natural causes. We identified 14 754 individuals (879 deaths) with serious mental illness (SMI) including schizophrenia, schizoaffective and bipolar disorders aged ≥ 15 years in a large specialist mental healthcare case register linked to national mortality tracing. In this cohort study we modeled the effect of clozapine on mortality over a 5-year period (2007–2011) using Cox regression. Individuals prescribed clozapine had more severe psychopathology and poorer functional status. Many of the exposures associated with clozapine use were themselves risk factors for increased mortality. However, we identified a strong association between being prescribed clozapine and lower mortality which persisted after controlling for a broad range of potential confounders including clinical monitoring and markers of disease severity (adjusted hazard ratio 0.4; 95% CI 0.2–0.7; p = .001). This association remained after restricting the sample to those with a diagnosis of schizophrenia or those taking antipsychotics and after using propensity scores to reduce the impact of confounding by indication. Among individuals with SMI, those prescribed clozapine had a reduced risk of mortality due to both natural and unnatural causes. We found no evidence to indicate that lower mortality associated with clozapine in SMI was due to increased clinical monitoring or confounding factors. This is the first study to report an association between clozapine and reduced risk of mortality from natural causes. PMID:25154620

  11. Statin adherence and risk of acute cardiovascular events among women: a cohort study accounting for time-dependent confounding affected by previous adherence

    PubMed Central

    Lavikainen, Piia; Helin-Salmivaara, Arja; Eerola, Mervi; Fang, Gang; Hartikainen, Juha; Huupponen, Risto; Korhonen, Maarit Jaana

    2016-01-01

    Objectives Previous studies on the effect of statin adherence on cardiovascular events in the primary prevention of cardiovascular disease have adjusted for time-dependent confounding, but potentially introduced bias into their estimates as adherence and confounders were measured simultaneously. We aimed to evaluate the effect when accounting for time-dependent confounding affected by previous adherence as well as time sequence between factors. Design Retrospective cohort study. Setting Finnish healthcare registers. Participants Women aged 45–64 years initiating statin use for primary prevention of cardiovascular disease in 2001–2004 (n=42 807). Outcomes Acute cardiovascular event defined as a composite of acute coronary syndrome and acute ischaemic stroke was our primary outcome. Low-energy fractures were used as a negative control outcome to evaluate the healthy-adherer effect. Results During the 3-year follow-up, 474 women experienced the primary outcome event and 557 suffered a low-energy fracture. The causal HR estimated with marginal structural model for acute cardiovascular events for all the women who remained adherent (proportion of days covered ≥80%) to statin therapy during the previous adherence assessment year was 0.78 (95% CI: 0.65 to 0.94) when compared with everybody remaining non-adherent (proportion of days covered <80%). The result was robust against alternative model specifications. Statin adherers had a potentially reduced risk of experiencing low-energy fractures compared with non-adherers (HR 0.90, 95% CI 0.76 to 1.07). Conclusions Our study, which took into account the time dependence of adherence and confounders, as well as temporal order between these factors, is support for the concept that adherence to statins in women in primary prevention decreases the risk of acute cardiovascular events by about one-fifth in comparison to non-adherence. However, part of the observed effect of statin adherence on acute cardiovascular events

  12. Influence of potentially confounding factors on sea urchin porewater toxicity tests

    USGS Publications Warehouse

    Carr, R.S.; Biedenbach, J.M.; Nipper, M.

    2006-01-01

    The influence of potentially confounding factors has been identified as a concern for interpreting sea urchin porewater toxicity test data. The results from >40 sediment-quality assessment surveys using early-life stages of the sea urchin Arbacia punctulata were compiled and examined to determine acceptable ranges of natural variables such as pH, ammonia, and dissolved organic carbon on the fertilization and embryological development endpoints. In addition, laboratory experiments were also conducted with A. punctulata and compared with information from the literature. Pore water with pH as low as 6.9 is an unlikely contributor to toxicity for the fertilization and embryological development tests with A. punctulata. Other species of sea urchin have narrower pH tolerance ranges. Ammonia is rarely a contributing factor in pore water toxicity tests using the fertilization endpoint, but the embryological development endpoint may be influenced by ammonia concentrations commonly found in porewater samples. Therefore, ammonia needs to be considered when interpreting results for the embryological development test. Humic acid does not affect sea urchin fertilization at saturation concentrations, but it could have an effect on the embryological development endpoint at near-saturation concentrations. There was no correlation between sediment total organic carbon concentrations and porewater dissolved organic carbon concentrations. Because of the potential for many varying substances to activate parthenogenesis in sea urchin eggs, it is recommended that a no-sperm control be included with every fertilization test treatment. ?? 2006 Springer Science+Business Media, Inc.

  13. Influence of potentially confounding factors on sea urchin porewater toxicity tests.

    PubMed

    Carr, R S; Biedenbach, J M; Nipper, M

    2006-11-01

    The influence of potentially confounding factors has been identified as a concern for interpreting sea urchin porewater toxicity test data. The results from >40 sediment-quality assessment surveys using early-life stages of the sea urchin Arbacia punctulata were compiled and examined to determine acceptable ranges of natural variables such as pH, ammonia, and dissolved organic carbon on the fertilization and embryological development endpoints. In addition, laboratory experiments were also conducted with A. punctulata and compared with information from the literature. Pore water with pH as low as 6.9 is an unlikely contributor to toxicity for the fertilization and embryological development tests with A. punctulata. Other species of sea urchin have narrower pH tolerance ranges. Ammonia is rarely a contributing factor in pore water toxicity tests using the fertilization endpoint, but the embryological development endpoint may be influenced by ammonia concentrations commonly found in porewater samples. Therefore, ammonia needs to be considered when interpreting results for the embryological development test. Humic acid does not affect sea urchin fertilization at saturation concentrations, but it could have an effect on the embryological development endpoint at near-saturation concentrations. There was no correlation between sediment total organic carbon concentrations and porewater dissolved organic carbon concentrations. Because of the potential for many varying substances to activate parthenogenesis in sea urchin eggs, it is recommended that a no-sperm control be included with every fertilization test treatment.

  14. Phenotypic variation as an indicator of pesticide stress in gudgeon: Accounting for confounding factors in the wild.

    PubMed

    Shinn, Cândida; Blanchet, Simon; Loot, Géraldine; Lek, Sovan; Grenouillet, Gaël

    2015-12-15

    The response of organisms to environmental stress is currently used in the assessment of ecosystem health. Morphological changes integrate the multiple effects of one or several stress factors upon the development of the exposed organisms. In a natural environment, many factors determine the patterns of morphological differentiation between individuals. However, few studies have sought to distinguish and measure the independent effect of these factors (genetic diversity and structure, spatial structuring of populations, physical-chemical conditions, etc.). Here we investigated the relationship between pesticide levels measured at 11 sites sampled in rivers of the Garonne river basin (SW France) and morphological changes of a freshwater fish species, the gudgeon (Gobio gobio). Each individual sampled was genotyped using 8 microsatellite markers and their phenotype characterized via 17 morphological traits. Our analysis detected a link between population genetic structure (revealed by a Bayesian method) and morphometry (linear discriminant analysis) of the studied populations. We then developed an original method based on general linear models using distance matrices, an extension of the partial Mantel test beyond 3 matrices. This method was used to test the relationship between contamination (toxicity index) and morphometry (PST of morphometric traits), taking into account (1) genetic differentiation between populations (FST), (2) geographical distances between sites, (3) site catchment area, and (4) various physical-chemical parameters for each sampling site. Upon removal of confounding effects, 3 of the 17 morphological traits studied were significantly correlated with pesticide toxicity, suggesting a response of these traits to the anthropogenic stress. These results underline the importance of taking into account the different sources of phenotypic variability between organisms when identifying the stress factors involved. The separation and quantification of

  15. Phenotypic variation as an indicator of pesticide stress in gudgeon: Accounting for confounding factors in the wild.

    PubMed

    Shinn, Cândida; Blanchet, Simon; Loot, Géraldine; Lek, Sovan; Grenouillet, Gaël

    2015-12-15

    The response of organisms to environmental stress is currently used in the assessment of ecosystem health. Morphological changes integrate the multiple effects of one or several stress factors upon the development of the exposed organisms. In a natural environment, many factors determine the patterns of morphological differentiation between individuals. However, few studies have sought to distinguish and measure the independent effect of these factors (genetic diversity and structure, spatial structuring of populations, physical-chemical conditions, etc.). Here we investigated the relationship between pesticide levels measured at 11 sites sampled in rivers of the Garonne river basin (SW France) and morphological changes of a freshwater fish species, the gudgeon (Gobio gobio). Each individual sampled was genotyped using 8 microsatellite markers and their phenotype characterized via 17 morphological traits. Our analysis detected a link between population genetic structure (revealed by a Bayesian method) and morphometry (linear discriminant analysis) of the studied populations. We then developed an original method based on general linear models using distance matrices, an extension of the partial Mantel test beyond 3 matrices. This method was used to test the relationship between contamination (toxicity index) and morphometry (PST of morphometric traits), taking into account (1) genetic differentiation between populations (FST), (2) geographical distances between sites, (3) site catchment area, and (4) various physical-chemical parameters for each sampling site. Upon removal of confounding effects, 3 of the 17 morphological traits studied were significantly correlated with pesticide toxicity, suggesting a response of these traits to the anthropogenic stress. These results underline the importance of taking into account the different sources of phenotypic variability between organisms when identifying the stress factors involved. The separation and quantification of

  16. Accounting for genetic and environmental confounds in associations between parent and child characteristics: a systematic review of children-of-twins studies.

    PubMed

    McAdams, Tom A; Neiderhiser, Jenae M; Rijsdijk, Fruhling V; Narusyte, Jurgita; Lichtenstein, Paul; Eley, Thalia C

    2014-07-01

    Parental psychopathology, parenting style, and the quality of intrafamilial relationships are all associated with child mental health outcomes. However, most research can say little about the causal pathways underlying these associations. This is because most studies are not genetically informative and are therefore not able to account for the possibility that associations are confounded by gene-environment correlation. That is, biological parents not only provide a rearing environment for their child, but also contribute 50% of their genes. Any associations between parental phenotype and child phenotype are therefore potentially confounded. One technique for disentangling genetic from environmental effects is the children-of-twins (COT) method. This involves using data sets comprising twin parents and their children to distinguish genetic from environmental associations between parent and child phenotypes. The COT technique has grown in popularity in the last decade, and we predict that this surge in popularity will continue. In the present article we explain the COT method for those unfamiliar with its use. We present the logic underlying this approach, discuss strengths and weaknesses, and highlight important methodological considerations for researchers interested in the COT method. We also cover variations on basic COT approaches, including the extended-COT method, capable of distinguishing forms of gene-environment correlation. We then present a systematic review of all the behavioral COT studies published to date. These studies cover such diverse phenotypes as psychosis, substance abuse, internalizing, externalizing, parenting, and marital difficulties. In reviewing this literature, we highlight past applications, identify emergent patterns, and suggest avenues for future research.

  17. Non-Chemical Distant Cellular Interactions as a potential confounder of cell biology experiments.

    PubMed

    Farhadi, Ashkan

    2014-01-01

    Distant cells can communicate with each other through a variety of methods. Two such methods involve electrical and/or chemical mechanisms. Non-chemical, distant cellular interactions may be another method of communication that cells can use to modify the behavior of other cells that are mechanically separated. Moreover, non-chemical, distant cellular interactions may explain some cases of confounding effects in Cell Biology experiments. In this article, we review non-chemical, distant cellular interactions studies to try to shed light on the mechanisms in this highly unconventional field of cell biology. Despite the existence of several theories that try to explain the mechanism of non-chemical, distant cellular interactions, this phenomenon is still speculative. Among candidate mechanisms, electromagnetic waves appear to have the most experimental support. In this brief article, we try to answer a few key questions that may further clarify this mechanism.

  18. Task-independent effects are potential confounders in longitudinal imaging studies of learning in schizophrenia

    PubMed Central

    Korostil, Michele; Fatima, Zainab; Kovacevic, Natasha; Menon, Mahesh; McIntosh, Anthony Randal

    2015-01-01

    Learning impairment is a core deficit in schizophrenia that impacts on real-world functioning and yet, elucidating its underlying neural basis remains a challenge. A key issue when interpreting learning-task experiments is that task-independent changes may confound interpretation of task-related signal changes in neuroimaging studies. The nature of these task-independent changes in schizophrenia is unknown. Therefore, we examined task-independent “time effects” in a group of participants with schizophrenia contrasted with healthy participants in a longitudinal fMRI learning-experiment designed to allow for examination of non-specific effects of time. Flanking the learning portions of the experiment with a task-of-no-interest allowed us to extract task-independent BOLD changes. Task-independent effects occurred in both groups, but were more robust in the schizophrenia group. There was a significant interaction effect between group and time in a distributed activity pattern that included inferior and superior temporal regions, frontal areas (left anterior insula and superior medial gyri), and parietal areas (posterior cingulate cortices and precuneus). This pattern showed task-independent linear decrease in BOLD amplitude over the two scanning sessions for the schizophrenia group, but showed either opposite effect or no activity changes for the control group. There was a trend towards a correlation between task-independent effects and the presence of more negative symptoms in the schizophrenia group. The strong interaction between group and time suggests that both the scanning experience as a whole and the transition between task-types evokes a different response in persons with schizophrenia and may confound interpretation of learning-related longitudinal imaging experiments if not explicitly considered. PMID:26759790

  19. Task-independent effects are potential confounders in longitudinal imaging studies of learning in schizophrenia.

    PubMed

    Korostil, Michele; Fatima, Zainab; Kovacevic, Natasha; Menon, Mahesh; McIntosh, Anthony Randal

    2016-01-01

    Learning impairment is a core deficit in schizophrenia that impacts on real-world functioning and yet, elucidating its underlying neural basis remains a challenge. A key issue when interpreting learning-task experiments is that task-independent changes may confound interpretation of task-related signal changes in neuroimaging studies. The nature of these task-independent changes in schizophrenia is unknown. Therefore, we examined task-independent "time effects" in a group of participants with schizophrenia contrasted with healthy participants in a longitudinal fMRI learning-experiment designed to allow for examination of non-specific effects of time. Flanking the learning portions of the experiment with a task-of-no-interest allowed us to extract task-independent BOLD changes. Task-independent effects occurred in both groups, but were more robust in the schizophrenia group. There was a significant interaction effect between group and time in a distributed activity pattern that included inferior and superior temporal regions, frontal areas (left anterior insula and superior medial gyri), and parietal areas (posterior cingulate cortices and precuneus). This pattern showed task-independent linear decrease in BOLD amplitude over the two scanning sessions for the schizophrenia group, but showed either opposite effect or no activity changes for the control group. There was a trend towards a correlation between task-independent effects and the presence of more negative symptoms in the schizophrenia group. The strong interaction between group and time suggests that both the scanning experience as a whole and the transition between task-types evokes a different response in persons with schizophrenia and may confound interpretation of learning-related longitudinal imaging experiments if not explicitly considered.

  20. [COMPUTER TECHNOLOGY FOR ACCOUNTING OF CONFOUNDERS IN THE RISK ASSESSMENT IN COMPARATIVE STUDIES ON THE BASE OF THE METHOD OF STANDARDIZATION].

    PubMed

    Shalaumova, Yu V; Varaksin, A N; Panov, V G

    2016-01-01

    There was performed an analysis of the accounting of the impact of concomitant variables (confounders), introducing a systematic error in the assessment of the impact of risk factors on the resulting variable. The analysis showed that standardization is an effective method for the reduction of the shift of risk assessment. In the work there is suggested an algorithm implementing the method of standardization based on stratification, providing for the minimization of the difference of distributions of confounders in groups on risk factors. To automate the standardization procedures there was developed a software available on the website of the Institute of Industrial Ecology, UB RAS. With the help of the developed software by numerically modeling there were determined conditions of the applicability of the method of standardization on the basis of stratification for the case of the normal distribution on the response and confounder and linear relationship between them. Comparison ofresults obtained with the help of the standardization with statistical methods (logistic regression and analysis of covariance) in solving the problem of human ecology, has shown that obtaining close results is possible if there will be met exactly conditions for the applicability of statistical methods. Standardization is less sensitive to violations of conditions of applicability. PMID:27266034

  1. [COMPUTER TECHNOLOGY FOR ACCOUNTING OF CONFOUNDERS IN THE RISK ASSESSMENT IN COMPARATIVE STUDIES ON THE BASE OF THE METHOD OF STANDARDIZATION].

    PubMed

    Shalaumova, Yu V; Varaksin, A N; Panov, V G

    2016-01-01

    There was performed an analysis of the accounting of the impact of concomitant variables (confounders), introducing a systematic error in the assessment of the impact of risk factors on the resulting variable. The analysis showed that standardization is an effective method for the reduction of the shift of risk assessment. In the work there is suggested an algorithm implementing the method of standardization based on stratification, providing for the minimization of the difference of distributions of confounders in groups on risk factors. To automate the standardization procedures there was developed a software available on the website of the Institute of Industrial Ecology, UB RAS. With the help of the developed software by numerically modeling there were determined conditions of the applicability of the method of standardization on the basis of stratification for the case of the normal distribution on the response and confounder and linear relationship between them. Comparison ofresults obtained with the help of the standardization with statistical methods (logistic regression and analysis of covariance) in solving the problem of human ecology, has shown that obtaining close results is possible if there will be met exactly conditions for the applicability of statistical methods. Standardization is less sensitive to violations of conditions of applicability.

  2. Evaluation of potential confounding factors in sediment toxicity tests with three freshwater benthic invertebrates

    SciTech Connect

    Ankley, G.T.; Benoit, D.A. ); Balogh, J.C. ); Reynoldson, T.B.; Day, K.E. ); Hoke, R.A. )

    1994-04-01

    The authors examined the effects of natural sediment physicochemical properties on the results of lab tests with the amphipod Hyalella azteca, the midge Chironomus tentans, and the oligochaete Lumbriculus variegatus. Ten-day exposures with the three species were conducted with 50 uncontaminated sediment samples from Lakes Erie, Huron, Superior, and Ontario, which differed markedly with regard to characteristics such as grain-size distribution, organic carbon content, and mineralogical composition. Tests were conducted both with and without the addition of exogenous food. Survival of Hyalella azteca, survival and growth of Chironomus tentans, and survival/reproduction and growth of Lumbriculus variegatus were significantly greater in tests in which the animals were fed vs, those in which they were not. Approximately 10% of the tests in which Hyalella azteca was not fed and 80% of tests in which the amphipods were fed resulted in >80% survival, a common criterion for defining the acceptability of tests with Hyalella azteca in clean control sediments. Similarly, a relatively high percentage of the tests in which Chironomus tentans was not fed would have failed a control survival criterion of 70% for the midge. Hence, there is significant potential for false positive results if Hyalella azteca or Chironomus tentans is not fed during sediment tests. Predictive modeling of the assay results in relationship to sediment physicochemical characteristics failed to reveal any additional factors that influenced survival of Hyalella azteca and Chrionomus tentans, or reproduction and growth of Lumbriculus variegatus in tests in which the organisms were fed. However, linear modeling did suggest that growth of fed as well as unfed Chironomus tentans may have been influenced by grain-size distribution of the test sediments.

  3. Potential confounds in estimating trial-to-trial correlations between neuronal response and behavior using choice probabilities

    PubMed Central

    Maunsell, John H. R.

    2012-01-01

    Correlations between trial-to-trial fluctuations in the responses of individual sensory neurons and perceptual reports, commonly quantified with choice probability (CP), have been widely used as an important tool for assessing the contributions of neurons to behavior. These correlations are usually weak and often require a large number of trials for a reliable estimate. Therefore, working with measures such as CP warrants care in data analysis as well as rigorous controls during data collection. Here we identify potential confounds that can arise in data analysis and lead to biased estimates of CP, and suggest methods to avoid the bias. In particular, we show that the common practice of combining neuronal responses across different stimulus conditions with z-score normalization can result in an underestimation of CP when the ratio of the numbers of trials for the two behavioral response categories differs across the stimulus conditions. We also discuss the effects of using variable time intervals for quantifying neuronal response on CP measurements. Finally, we demonstrate that serious artifacts can arise in reaction time tasks that use varying measurement intervals if the mean neuronal response and mean behavioral performance vary over time within trials. To emphasize the importance of addressing these concerns in neurophysiological data, we present a set of data collected from V1 cells in macaque monkeys while the animals performed a detection task. PMID:22993262

  4. Global climate change in large European rivers: long-term effects on macroinvertebrate communities and potential local confounding factors.

    PubMed

    Floury, Mathieu; Usseglio-Polatera, Philippe; Ferreol, Martial; Delattre, Cecile; Souchon, Yves

    2013-04-01

    Aquatic species living in running waters are widely acknowledged to be vulnerable to climate-induced, thermal and hydrological fluctuations. Climate changes can interact with other environmental changes to determine structural and functional attributes of communities. Although such complex interactions are most likely to occur in a multiple-stressor context as frequently encountered in large rivers, they have received little attention in such ecosystems. In this study, we aimed at specifically addressing the issue of relative long-term effects of global and local changes on benthic macroinvertebrate communities in multistressed large rivers. We assessed effects of hydroclimatic vs. water quality factors on invertebrate community structure and composition over 30 years (1979-2008) in the Middle Loire River, France. As observed in other large European rivers, water warming over the three decades (+0.9 °C between 1979-1988 and 1999-2008) and to a lesser extent discharge reduction (-80 m(3) s(-1) ) were significantly involved in the disappearance or decrease in taxa typical from fast running, cold waters (e.g. Chloroperlidae and Potamanthidae). They explained also a major part of the appearance and increase of taxa typical from slow flowing or standing waters and warmer temperatures, including invasive species (e.g. Corbicula sp. and Atyaephyra desmarestii). However, this shift towards a generalist and pollution tolerant assemblage was partially confounded by local improvement in water quality (i.e. phosphate input reduction by about two thirds and eutrophication limitation by almost one half), explaining a significant part of the settlement of new pollution-sensitive taxa (e.g. the caddisfly Brachycentridae and Philopotamidae families) during the last years of the study period. The regain in such taxa allowed maintaining a certain level of specialization in the invertebrate community despite climate change effects.

  5. A population-based study of edentulism in the US: does depression and rural residency matter after controlling for potential confounders?

    PubMed Central

    2014-01-01

    Background Oral health is an integral component of general health and well-being. While edentulism has been examined in relation to socioeconomic status, rural residency, chronic disease and mental health, no study that we know of has examined edentulism and these factors together. The objective of this study was to determine whether depression and rural residency were significantly associated with partial and full edentulism in US adults after controlling for potential confounders. Methods 2006 Behavioral Risk Factor Surveillance Survey (BRFSS) data were analyzed to identify factors associated with increased odds of partial or full edentulism. This year of BRFSS data was chosen for analysis because in this year the standardized and validated Personal Health Questionnaire-8 (PHQ-8) was used to measure current depression. This measure was part of the optional questions BRFSS asks, and in 2006 33 states and/or territories included them in their annual surveillance data collection. Bivariate and logistic regression analyses were performed on weighted BRFSS data. Results Logistic regression analysis using either full or partial edentulism as the dependent variable yielded that rural residency or living in a rural locale, low and/or middle socioeconomic status (SES), depression as measured by the PHQ-8, and African American race/ethnicity were all independent risk factors when controlling for these and a number of additional covariates. Conclusions This study adds to the epidemiological literature by assessing partial and full edentulism in the US utilizing data from the CDC’s Behavioral Risk Factor Surveillance System (BRFSS). Examining data collected through a large national surveillance system such as BRFSS allows for an analysis that incorporates an array of covariates not available from clinically-based data alone. This study demonstrated that current depression and rural residency are important factors related to partial and full edentulism after controlling for

  6. The ACCE method: an approach for obtaining quantitative or qualitative estimates of residual confounding that includes unmeasured confounding

    PubMed Central

    Smith, Eric G.

    2015-01-01

    Background:  Nonrandomized studies typically cannot account for confounding from unmeasured factors.  Method:  A method is presented that exploits the recently-identified phenomenon of  “confounding amplification” to produce, in principle, a quantitative estimate of total residual confounding resulting from both measured and unmeasured factors.  Two nested propensity score models are constructed that differ only in the deliberate introduction of an additional variable(s) that substantially predicts treatment exposure.  Residual confounding is then estimated by dividing the change in treatment effect estimate between models by the degree of confounding amplification estimated to occur, adjusting for any association between the additional variable(s) and outcome. Results:  Several hypothetical examples are provided to illustrate how the method produces a quantitative estimate of residual confounding if the method’s requirements and assumptions are met.  Previously published data is used to illustrate that, whether or not the method routinely provides precise quantitative estimates of residual confounding, the method appears to produce a valuable qualitative estimate of the likely direction and general size of residual confounding. Limitations:  Uncertainties exist, including identifying the best approaches for: 1) predicting the amount of confounding amplification, 2) minimizing changes between the nested models unrelated to confounding amplification, 3) adjusting for the association of the introduced variable(s) with outcome, and 4) deriving confidence intervals for the method’s estimates (although bootstrapping is one plausible approach). Conclusions:  To this author’s knowledge, it has not been previously suggested that the phenomenon of confounding amplification, if such amplification is as predictable as suggested by a recent simulation, provides a logical basis for estimating total residual confounding. The method's basic approach is

  7. Associations of Perfluoroalkyl Substances (PFAS) with Lower Birth Weight: An Evaluation of Potential Confounding by Glomerular Filtration Rate Using a Physiologically Based Pharmacokinetic Model (PBPK)

    PubMed Central

    Loccisano, Anne E.; Morken, Nils-Halvdan; Yoon, Miyoung; Wu, Huali; McDougall, Robin; Maisonet, Mildred; Marcus, Michele; Kishi, Reiko; Miyashita, Chihiro; Chen, Mei-Huei; Hsieh, Wu-Shiun; Andersen, Melvin E.; Clewell, Harvey J.; Longnecker, Matthew P.

    2015-01-01

    Dougall R, Maisonet M, Marcus M, Kishi R, Miyashita C, Chen MH, Hsieh WS, Andersen ME, Clewell HJ III, Longnecker MP. 2015. Associations of perfluoroalkyl substances (PFAS) with lower birth weight: an evaluation of potential confounding by glomerular filtration rate using a physiologically based pharmacokinetic model (PBPK). Environ Health Perspect 123:1317–1324; http://dx.doi.org/10.1289/ehp.1408837 PMID:26008903

  8. Distance to high-voltage power lines and risk of childhood leukemia--an analysis of confounding by and interaction with other potential risk factors.

    PubMed

    Pedersen, Camilla; Bräuner, Elvira V; Rod, Naja H; Albieri, Vanna; Andersen, Claus E; Ulbak, Kaare; Hertel, Ole; Johansen, Christoffer; Schüz, Joachim; Raaschou-Nielsen, Ole

    2014-01-01

    We investigated whether there is an interaction between distance from residence at birth to nearest power line and domestic radon and traffic-related air pollution, respectively, in relation to childhood leukemia risk. Further, we investigated whether adjusting for potential confounders alters the association between distance to nearest power line and childhood leukemia. We included 1024 cases aged <15, diagnosed with leukemia during 1968-1991, from the Danish Cancer Registry and 2048 controls randomly selected from the Danish childhood population and individually matched by gender and year of birth. We used geographical information systems to determine the distance between residence at birth and the nearest 132-400 kV overhead power line. Concentrations of domestic radon and traffic-related air pollution (NOx at the front door) were estimated using validated models. We found a statistically significant interaction between distance to nearest power line and domestic radon regarding risk of childhood leukemia (p = 0.01) when using the median radon level as cut-off point but not when using the 75th percentile (p = 0.90). We found no evidence of an interaction between distance to nearest power line and traffic-related air pollution (p = 0.73). We found almost no change in the estimated association between distance to power line and risk of childhood leukemia when adjusting for socioeconomic status of the municipality, urbanization, maternal age, birth order, domestic radon and traffic-related air pollution. The statistically significant interaction between distance to nearest power line and domestic radon was based on few exposed cases and controls and sensitive to the choice of exposure categorization and might, therefore, be due to chance. PMID:25259740

  9. Identifiability, exchangeability and confounding revisited

    PubMed Central

    Greenland, Sander; Robins, James M

    2009-01-01

    In 1986 the International Journal of Epidemiology published "Identifiability, Exchangeability and Epidemiological Confounding". We review the article from the perspective of a quarter century after it was first drafted and relate it to subsequent developments on confounding, ignorability, and collapsibility. PMID:19732410

  10. Interpretational Confounding or Confounded Interpretations of Causal Indicators?

    ERIC Educational Resources Information Center

    Bainter, Sierra A.; Bollen, Kenneth A.

    2014-01-01

    In measurement theory, causal indicators are controversial and little understood. Methodological disagreement concerning causal indicators has centered on the question of whether causal indicators are inherently sensitive to interpretational confounding, which occurs when the empirical meaning of a latent construct departs from the meaning…

  11. Modeling confounding by half-sibling regression.

    PubMed

    Schölkopf, Bernhard; Hogg, David W; Wang, Dun; Foreman-Mackey, Daniel; Janzing, Dominik; Simon-Gabriel, Carl-Johann; Peters, Jonas

    2016-07-01

    We describe a method for removing the effect of confounders to reconstruct a latent quantity of interest. The method, referred to as "half-sibling regression," is inspired by recent work in causal inference using additive noise models. We provide a theoretical justification, discussing both independent and identically distributed as well as time series data, respectively, and illustrate the potential of the method in a challenging astronomy application. PMID:27382154

  12. Modeling confounding by half-sibling regression.

    PubMed

    Schölkopf, Bernhard; Hogg, David W; Wang, Dun; Foreman-Mackey, Daniel; Janzing, Dominik; Simon-Gabriel, Carl-Johann; Peters, Jonas

    2016-07-01

    We describe a method for removing the effect of confounders to reconstruct a latent quantity of interest. The method, referred to as "half-sibling regression," is inspired by recent work in causal inference using additive noise models. We provide a theoretical justification, discussing both independent and identically distributed as well as time series data, respectively, and illustrate the potential of the method in a challenging astronomy application.

  13. Modeling confounding by half-sibling regression

    PubMed Central

    Schölkopf, Bernhard; Hogg, David W.; Wang, Dun; Foreman-Mackey, Daniel; Janzing, Dominik; Simon-Gabriel, Carl-Johann; Peters, Jonas

    2016-01-01

    We describe a method for removing the effect of confounders to reconstruct a latent quantity of interest. The method, referred to as “half-sibling regression,” is inspired by recent work in causal inference using additive noise models. We provide a theoretical justification, discussing both independent and identically distributed as well as time series data, respectively, and illustrate the potential of the method in a challenging astronomy application. PMID:27382154

  14. Biosolids impact soil phosphorus accountability, fractionation, and potential environmental risk.

    PubMed

    Ippolito, J A; Barbarick, K A; Norvell, K L

    2007-01-01

    Biosolids land application rates are typically based on crop N requirements but can lead to soil P accumulation. The Littleton/Englewood, Colorado, wastewater treatment facility has supported biosolids beneficial-use on a dryland wheat-fallow agroecosystem site since 1982, with observable soil P concentration increases as biyearly repeated biosolids applications increased from 0, 6.7, 13, 27, to 40 Mg ha(-1). The final study year was 2003, after which P accountability, fractionation, and potential environmental risk were assessed. Between 93 and 128% of biosolids-P added was accounted for when considering conventional tillage soil displacement, grain removal, and soil adsorption. The Fe-P fraction dominated all soil surface P fractions, likely due to an increase in amorphous Fe-oxide because Fe2(SO4)3 was added at the wastewater treatment facility inflow for digester H2S reduction. The Ca-P phase dominated all soil subsurface P fractions due to calcareous soil conditions. A combination of conventional tillage, drought from 1999 to 2003, and repeated and increasing biosolids application rates may have forced soil surface microorganism dormancy, reduction, or mortality; thus, biomass P reduction was evident. Subsurface biomass P was greater than surface biomass, possibly due to protection against environmental and anthropogenic variables or to increased dissolved organic carbon inputs. Even given years of biosolids application, the soil surface had the ability to sorb additional P as determined by shaking the soil in an excessive P solution. Biosolids-application regulations based on the Colorado Phosphorus Index would not impede current site practices. Proper monitoring, management, and addition of other best management practices are needed for continued assurance that P movement off-site does not become a major issue. PMID:17412911

  15. Resting-state FMRI confounds and cleanup

    PubMed Central

    Murphy, Kevin; Birn, Rasmus M.; Bandettini, Peter A.

    2013-01-01

    The goal of resting-state functional magnetic resonance imaging (FMRI) is to investigate the brain’s functional connections by using the temporal similarity between blood oxygenation level dependent (BOLD) signals in different regions of the brain “at rest” as an indicator of synchronous neural activity. Since this measure relies on the temporal correlation of FMRI signal changes between different parts of the brain, any non-neural activity-related process that affects the signals will influence the measure of functional connectivity, yielding spurious results. To understand the sources of these resting-state FMRI confounds, this article describes the origins of the BOLD signal in terms of MR physics and cerebral physiology. Potential confounds arising from motion, cardiac and respiratory cycles, arterial CO2 concentration, blood pressure/cerebral autoregulation, and vasomotion are discussed. Two classes of techniques to remove confounds from resting-state BOLD time series are reviewed: 1) those utilising external recordings of physiology and 2) data-based cleanup methods that only use the resting-state FMRI data itself. Further methods that remove noise from functional connectivity measures at a group level are also discussed. For successful interpretation of resting-state FMRI comparisons and results, noise cleanup is an often over-looked but essential step in the analysis pipeline. PMID:23571418

  16. Education, Accountability, and the Ethical Demand: Can the Democratic Potential of Accountability Be Regained?

    ERIC Educational Resources Information Center

    Biesta, Gert J. J.

    2004-01-01

    This paper analyzes the impact of the idea of accountability on education. It considers the kind of relationships that are promoted or produced by the culture of accountability, both in order to understand what kind of relationships are made possible and to understand what kind of relationships are made difficult, or even impossible, as a result…

  17. Ace Your Accounting Classes: 12 Hints to Maximize Your Potential

    ERIC Educational Resources Information Center

    Albrecht, W. David

    2008-01-01

    Many students experience difficulties when they try to get good grades in their accounting classes, and they are searching for answers. There is no single answer. Getting a good grade in an accounting class results from a process. If you know and understand the process--and can apply it--then your chances are much improved for getting a good…

  18. Stewardship and Accountability: Valued Elements in Maximising Human Potential.

    ERIC Educational Resources Information Center

    Todd, Sally M.

    1998-01-01

    Explains the application of five principles of stewardship to the education of gifted children: (1) teachers/parents teach correct principles; (2) students set their own goals in harmony with these principles; (3) teachers serve students as a source of help; (4) students ask for and receive help when needed; and (5) students give an accounting of…

  19. Accountability.

    ERIC Educational Resources Information Center

    Mullen, David J., Ed.

    This monograph, prepared to assist Georgia elementary principals to better understand accountability and its implications for educational improvement, sets forth many of the theoretical and philosophical bases from which accountability is being considered. Leon M. Lessinger begins this 5-paper presentation by describing the need for accountability…

  20. Accountability.

    ERIC Educational Resources Information Center

    Lashway, Larry

    1999-01-01

    This issue reviews publications that provide a starting point for principals looking for a way through the accountability maze. Each publication views accountability differently, but collectively these readings argue that even in an era of state-mandated assessment, principals can pursue proactive strategies that serve students' needs. James A.…

  1. Accountability.

    ERIC Educational Resources Information Center

    The Newsletter of the Comprehensive Center-Region VI, 1999

    1999-01-01

    Controversy surrounding the accountability movement is related to how the movement began in response to dissatisfaction with public schools. Opponents see it as one-sided, somewhat mean-spirited, and a threat to the professional status of teachers. Supporters argue that all other spheres of the workplace have accountability systems and that the…

  2. Sensitivity analysis for interactions under unmeasured confounding.

    PubMed

    Vanderweele, Tyler J; Mukherjee, Bhramar; Chen, Jinbo

    2012-09-28

    We develop a sensitivity analysis technique to assess the sensitivity of interaction analyses to unmeasured confounding. We give bias formulas for sensitivity analysis for interaction under unmeasured confounding on both additive and multiplicative scales. We provide simplified formulas in the case in which either one of the two factors does not interact with the unmeasured confounder in its effects on the outcome. An interesting consequence of the results is that if the two exposures of interest are independent (e.g., gene-environment independence), even under unmeasured confounding, if the estimate of the interaction is nonzero, then either there is a true interaction between the two factors or there is an interaction between one of the factors and the unmeasured confounder; an interaction must be present in either scenario. We apply the results to two examples drawn from the literature.

  3. Air Pollution and Autism Spectrum Disorders: Causal or Confounded?

    PubMed

    Weisskopf, Marc G; Kioumourtzoglou, Marianthi-Anna; Roberts, Andrea L

    2015-12-01

    In the last decade, several studies have examined the association between perinatal exposure to ambient air pollution and risk of autism spectrum disorder (ASD). These studies have largely been consistent, with associations seen with different aspects of air pollution, including hazardous air toxics, ozone, particulate, and traffic-related pollution. Confounding by socioeconomic status (SES) and place of residence are of particular concern, as these can be related to ASD case ascertainment and other potential causal risk factors for ASD. While all studies take steps to address this concern, residual confounding is difficult to rule out. Two recent studies of air pollution and ASD, however, present findings that strongly argue against residual confounding, especially for factors that do not vary over relatively short time intervals. These two studies, conducted in communities around the USA, found a specific association with air pollution exposure during the 3rd, but not the 1st, trimester, when both trimesters were modeled simultaneously. In this review, we discuss confounding possibilities and then explain-with the aid of directed acyclic graphs (DAGs)-why an association that is specific to a particular time window, when multiple exposure windows are simultaneously assessed, argues against residual confounding by (even unmeasured) non-time-varying factors. In addition, we discuss why examining ambient air pollution concentration as a proxy for personal exposure helps avoid confounding by personal behavior differences, and the implications of measurement error in using ambient concentrations as a proxy for personal exposures. Given the general consistency of findings across studies and the exposure-window-specific associations recently reported, the overall evidence for a causal association between air pollution and ASD is increasingly compelling.

  4. Packet Randomized Experiments for Eliminating Classes of Confounders

    PubMed Central

    Pavela, Greg; Wiener, Howard; Fontaine, Kevin R.; Fields, David A.; Voss, Jameson D.; Allison, David B.

    2014-01-01

    Background Although randomization is considered essential for causal inference, it is often not possible to randomize in nutrition and obesity research. To address this, we develop a framework for an experimental design—packet randomized experiments (PREs), which improves causal inferences when randomization on a single treatment variable is not possible. This situation arises when subjects are randomly assigned to a condition (such as a new roommate) which varies in one characteristic of interest (such as weight), but also varies across many others. There has been no general discussion of this experimental design, including its strengths, limitations, and statistical properties. As such, researchers are left to develop and apply PREs on an ad hoc basis, limiting its potential to improve causal inferences among nutrition and obesity researchers. Methods We introduce PREs as an intermediary design between randomized controlled trials and observational studies. We review previous research that used the PRE design and describe its application in obesity-related research, including random roommate assignments, heterochronic parabiosis, and the quasi-random assignment of subjects to geographic areas. We then provide a statistical framework to control for potential packet-level confounders not accounted for by randomization. Results PREs have successfully been used to improve causal estimates of the effect of roommates, altitude, and breastfeeding on weight outcomes. When certain assumptions are met, PREs can asymptotically control for packet-level characteristics. This has the potential to statistically estimate the effect of a single treatment even when randomization to a single treatment did not occur. Conclusions Applying PREs to obesity-related research will improve decisions about clinical, public health, and policy actions insofar as it offers researchers new insight into cause and effect relationships among variables. PMID:25444088

  5. Confounding by dietary pattern of the inverse association between alcohol consumption and type 2 diabetes risk

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Epidemiology of dietary components and disease risk limits interpretability due to potential residual confounding by correlated dietary components. Dietary pattern analyses by factor analysis or partial least squares may overcome the limitation. To examine confounding by dietary pattern as well as ...

  6. Confounding by dietary patterns of the inverse association between alcohol consumption and type 2 diabetes risk

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Epidemiology of dietary components and disease risk limits interpretability due to potential residual confounding by correlated dietary components. Dietary pattern analyses by factor analysis or partial least squares may overcome this limitation. To examine confounding by dietary pattern as well as ...

  7. Arsenic cancer risk confounder in southwest Taiwan data set.

    PubMed

    Lamm, Steven H; Engel, Arnold; Penn, Cecilia A; Chen, Rusan; Feinleib, Manning

    2006-07-01

    Quantitative analysis for the risk of human cancer from the ingestion of inorganic arsenic has been based on the reported cancer mortality experience in the blackfoot disease (BFD) -endemic area of southwest Taiwan. Linear regression analysis shows that arsenic as the sole etiologic factor accounts for only 21% of the variance in the village standardized mortality ratios for bladder and lung cancer. A previous study had reported the influence of confounders (township, BFD prevalence, and artesian well dependency) qualitatively, but they have not been introduced into a quantitative assessment. In this six-township study, only three townships (2, 4, and 6) showed a significant positive dose-response relationship with arsenic exposure. The other three townships (0, 3, and 5) demonstrated significant bladder and lung cancer risks that were independent of arsenic exposure. The data for bladder and lung cancer mortality for townships 2, 4, and 6 fit an inverse linear regression model (p < 0.001) with an estimated threshold at 151 microg/L (95% confidence interval, 42 to 229 microg/L) . Such a model is consistent with epidemiologic and toxicologic literature for bladder cancer. Exploration of the southwest Taiwan cancer mortality data set has clarified the dose-response relationship with arsenic exposure by separating out township as a confounding factor. Key words: arsenic, blackfoot disease, bladder cancer, cancer risk, confounder, dose-response relationship, southwest Taiwan, threshold model.

  8. [Bias and confounding: pharmacoepidemiological study using administrative database].

    PubMed

    Nojiri, Shuko

    2015-01-01

    The provision of health care frequently creates digitalized data such as hospital-based electronic data, medication prescription records, and claims data collectively termed "administrative database research". The data source and analytical opportunities for study create risks that can lead to misinterpretation or bias the results. This review serves as an introduction to the concept of bias and confounding to help researchers conduct methodologically sound pharmacoepidemiologic research projects using administrative databases. Beyond general considerations for observational study, there are several unique issues related to database research that should be addressed. The risks of uninterpretable or biased results can be minimized by: providing a robust description of the data tables used; focusing on why and how they were created; measuring and reporting the accuracy of diagnostic and procedural codes used; and properly accounting for any time-dependent nature of variables. The hallmark of good research is rigorously careful analysis and interpretation. The promise for value of real world evidence using databases in medical decision making must be balanced against concerns related to observational inherited limitations for bias and confounding. Researchers should aim to avoid bias in the design of a study, adjust for confounding, and discuss the effects of residual bias on the results. PMID:26028416

  9. A flexible, interpretable framework for assessing sensitivity to unmeasured confounding.

    PubMed

    Dorie, Vincent; Harada, Masataka; Carnegie, Nicole Bohme; Hill, Jennifer

    2016-09-10

    When estimating causal effects, unmeasured confounding and model misspecification are both potential sources of bias. We propose a method to simultaneously address both issues in the form of a semi-parametric sensitivity analysis. In particular, our approach incorporates Bayesian Additive Regression Trees into a two-parameter sensitivity analysis strategy that assesses sensitivity of posterior distributions of treatment effects to choices of sensitivity parameters. This results in an easily interpretable framework for testing for the impact of an unmeasured confounder that also limits the number of modeling assumptions. We evaluate our approach in a large-scale simulation setting and with high blood pressure data taken from the Third National Health and Nutrition Examination Survey. The model is implemented as open-source software, integrated into the treatSens package for the R statistical programming language. © 2016 The Authors. Statistics in Medicine Published by John Wiley & Sons Ltd. PMID:27139250

  10. Resting-state fMRI confounds and cleanup.

    PubMed

    Murphy, Kevin; Birn, Rasmus M; Bandettini, Peter A

    2013-10-15

    The goal of resting-state functional magnetic resonance imaging (fMRI) is to investigate the brain's functional connections by using the temporal similarity between blood oxygenation level dependent (BOLD) signals in different regions of the brain "at rest" as an indicator of synchronous neural activity. Since this measure relies on the temporal correlation of fMRI signal changes between different parts of the brain, any non-neural activity-related process that affects the signals will influence the measure of functional connectivity, yielding spurious results. To understand the sources of these resting-state fMRI confounds, this article describes the origins of the BOLD signal in terms of MR physics and cerebral physiology. Potential confounds arising from motion, cardiac and respiratory cycles, arterial CO₂ concentration, blood pressure/cerebral autoregulation, and vasomotion are discussed. Two classes of techniques to remove confounds from resting-state BOLD time series are reviewed: 1) those utilising external recordings of physiology and 2) data-based cleanup methods that only use the resting-state fMRI data itself. Further methods that remove noise from functional connectivity measures at a group level are also discussed. For successful interpretation of resting-state fMRI comparisons and results, noise cleanup is an often over-looked but essential step in the analysis pipeline.

  11. Confounding and heterogeneity in genetic association studies with admixed populations.

    PubMed

    Liu, Jinghua; Lewinger, Juan Pablo; Gilliland, Frank D; Gauderman, W James; Conti, David V

    2013-02-15

    Association studies among admixed populations pose many challenges including confounding of genetic effects due to population substructure and heterogeneity due to different patterns of linkage disequilibrium (LD). We use simulations to investigate controlling for confounding by indicators of global ancestry and the impact of including a covariate for local ancestry. In addition, we investigate the use of an interaction term between a single-nucleotide polymorphism (SNP) and local ancestry to capture heterogeneity in SNP effects. Although adjustment for global ancestry can control for confounding, additional adjustment for local ancestry may increase power when the induced admixture LD is in the opposite direction as the LD in the ancestral population. However, if the induced LD is in the same direction, there is the potential for reduced power because of overadjustment. Furthermore, the inclusion of a SNP by local ancestry interaction term can increase power when there is substantial differential LD between ancestry populations. We examine these approaches in genome-wide data using the University of Southern California's Children's Health Study investigating asthma risk. The analysis highlights rs10519951 (P = 8.5 × 10(-7)), a SNP lacking any evidence of association from a conventional analysis (P = 0.5).

  12. Zero-current potentials in a large membrane channel: a simple theory accounts for complex behavior.

    PubMed Central

    Zambrowicz, E B; Colombini, M

    1993-01-01

    Flow of ions through large channels is complex because both cations and anions can penetrate and multiple ions can be in the channel at the same time. A modification of the fixed-charge membrane theory of Teorell was reported (Peng, S., E. Blachly-Dyson, M. Forte, and M. Colombini. 1992. Biophys. J. 62:123-135) in which the channel is divided into two compartments: a relatively charged cylindrical shell of solution adjacent to the wall of the pore and a relatively neutral central cylinder of solution. The zero-current (reversal) potential results in current flow in opposite directions in these two compartments. This description accounted rather well for the observed reversal potential changes following site-directed mutations. Here we report the results of systematic tests of this simple theory with the mitochondrial channel, VDAC (isolated from Neurospora crassa), reconstituted into planar phospholipid membranes. The variation of the observed reversal potential with transmembrane activity ratio, ionic strength, ion mobility ratio, and net charge on the wall of the pore are accounted for reasonably well. The Goldman-Hodgkin-Katz theory fails to account for the observations. PMID:7694668

  13. Confounding Effect in Clinical Research of Otolaryngology and Its Control.

    PubMed

    Yu, Yong-qiang; Huang, Dong-yan; Armijo Olivo, Susan; Yang, Huai-an; Bambanini, Yagesh; Sonnenberg, Lyn; Clark, Brenda; Constantinescu, Gabriela; Qian Yu, Jason; Zhang, Ming

    2015-06-01

    Confounding effect is a critical issue in clinical research of otolaryngology because it can distort the research's conclusion. In this review, we introduce the definition of confounding effect, the methods of verifying and controlling the effect. Confounding effect can be prevented by research's design, and adjusted by data analysis. Clinicians would be aware and cautious about confounding effect in their research. They would be able to set up a research's design in which appropriate methods have been applied to prevent this effect.They would know how to adjust confounding effect after data collection. It is important to remember that sometimes it is impossible to eliminate confounding effect completely, and statistical method is not a master key. Solid research knowledge and critical thinking of our brain are the most important in controlling confounding effect. PMID:26149004

  14. Confounding Effect in Clinical Research of Otolaryngology and Its Control.

    PubMed

    Yu, Yong-qiang; Huang, Dong-yan; Armijo Olivo, Susan; Yang, Huai-an; Bambanini, Yagesh; Sonnenberg, Lyn; Clark, Brenda; Constantinescu, Gabriela; Qian Yu, Jason; Zhang, Ming

    2015-06-01

    Confounding effect is a critical issue in clinical research of otolaryngology because it can distort the research's conclusion. In this review, we introduce the definition of confounding effect, the methods of verifying and controlling the effect. Confounding effect can be prevented by research's design, and adjusted by data analysis. Clinicians would be aware and cautious about confounding effect in their research. They would be able to set up a research's design in which appropriate methods have been applied to prevent this effect.They would know how to adjust confounding effect after data collection. It is important to remember that sometimes it is impossible to eliminate confounding effect completely, and statistical method is not a master key. Solid research knowledge and critical thinking of our brain are the most important in controlling confounding effect.

  15. Still another confounded face in the crowd.

    PubMed

    Purcell, Dean G; Stewart, Alan L

    2010-11-01

    Experiments using schematic faces developed by Öhman (Öhman, Lundqvist, & Esteves, 2001) seem to document an anger-superiority effect, although we have come to question these experiments. Our work shows that the low-level features of these schematic faces interact with the face's surround to produce effects that have been attributed to facial affect. Using relatively neutral faces that preserved the feature and surround spatial relationships of angry and happy schematic faces, we produced reaction times (RTs) that were indistinguishable from those found with angry and happy faces. We also found that the target face's position within the crowd determined the magnitude of the advantage for angry faces as well as for relatively affect-neutral faces. Removing the facial surround reduces the advantage for angry faces, largely by improving performance on happy faces. There was an apparent small advantage for angry features without a surround. Öhman faces avoid the problems associated with modified grayscale faces only to introduce an equally troubling confound.

  16. Post-study therapy as a source of confounding in survival analysis of first-line studies in patients with advanced non-small-cell lung cancer

    PubMed Central

    Zietemann, Vera D; Schuster, Tibor; Duell, Thomas HG

    2011-01-01

    Clinical trials exploring the long-term effects of first-line therapy in patients with advanced non-small-cell lung cancer generally disregard subsequent treatment although most patients receive second and third-line therapies. The choice of further therapy depends on critical intermediate events such as disease progression and it is usually left at the physician’s discretion. Time-dependent confounding may then arise with standard survival analyses producing biased effect estimates, even in randomized trials. Herein we describe the concept of time-dependent confounding in detail and discuss whether the response to first-line treatment may be a potential time-dependent confounding factor for survival in the context of subsequent therapy. A prospective observational study of 406 patients with advanced non-small-cell lung cancer served as an example base. There is evidence that time-dependent confounding may occur in multivariate survival analysis after first-line therapy when disregarding subsequent treatment. In the light of this important but underestimated aspect some of the large and meaningful recent clinical first-line lung cancer studies are discussed, focussing on subsequent treatment and its potential impact on the survival of the study patients. No recently performed lung cancer trial applied adequate statistical analyses despite the frequent use of subsequent therapies. In conclusion, effect estimates from standard survival analysis may be biased even in randomized controlled trials because of time-dependent confounding. To adequately assess treatment effects on long-term outcomes appropriate statistical analyses need to take subsequent treatment into account. PMID:22263071

  17. Coping with confounds in multivoxel pattern analysis: what should we do about reaction time differences? A comment on Todd, Nystrom & Cohen 2013.

    PubMed

    Woolgar, Alexandra; Golland, Polina; Bode, Stefan

    2014-09-01

    Multivoxel pattern analysis (MVPA) is a sensitive and increasingly popular method for examining differences between neural activation patterns that cannot be detected using classical mass-univariate analysis. Recently, Todd et al. ("Confounds in multivariate pattern analysis: Theory and rule representation case study", 2013, NeuroImage 77: 157-165) highlighted a potential problem for these methods: high sensitivity to confounds at the level of individual participants due to the use of directionless summary statistics. Unlike traditional mass-univariate analyses where confounding activation differences in opposite directions tend to approximately average out at group level, group level MVPA results may be driven by any activation differences that can be discriminated in individual participants. In Todd et al.'s empirical data, factoring out differences in reaction time (RT) reduced a classifier's ability to distinguish patterns of activation pertaining to two task rules. This raises two significant questions for the field: to what extent have previous multivoxel discriminations in the literature been driven by RT differences, and by what methods should future studies take RT and other confounds into account? We build on the work of Todd et al. and compare two different approaches to remove the effect of RT in MVPA. We show that in our empirical data, in contrast to that of Todd et al., the effect of RT on rule decoding is negligible, and results were not affected by the specific details of RT modelling. We discuss the meaning of and sensitivity for confounds in traditional and multivoxel approaches to fMRI analysis. We observe that the increased sensitivity of MVPA comes at a price of reduced specificity, meaning that these methods in particular call for careful consideration of what differs between our conditions of interest. We conclude that the additional complexity of the experimental design, analysis and interpretation needed for MVPA is still not a reason to

  18. On the role of marginal confounder prevalence – implications for the high-dimensional propensity score algorithm

    PubMed Central

    Schuster, Tibor; Pang, Menglan; Platt, Robert W

    2016-01-01

    PURPOSE The high-dimensional propensity score algorithm attempts to improve control of confounding in typical treatment effect studies in pharmacoepidemiology and is increasingly being used for the analysis of large administrative databases. Within this multi-step variable selection algorithm, the marginal prevalence of non-zero covariate values is considered to be an indicator for a count variable's potential confounding impact. We investigate the role of the marginal prevalence of confounder variables on potentially caused bias magnitudes when estimating risk ratios in point exposure studies with binary outcomes. METHODS We apply the law of total probability in conjunction with an established bias formula to derive and illustrate relative bias boundaries with respect to marginal confounder prevalence. RESULTS We show that maximum possible bias magnitudes can occur at any marginal prevalence level of a binary confounder variable. In particular, we demonstrate that, in case of rare or very common exposures, low and high prevalent confounder variables can still have large confounding impact on estimated risk ratios. CONCLUSIONS Covariate pre-selection by prevalence may lead to sub-optimal confounder sampling within the high-dimensional propensity score algorithm. While we believe that the high-dimensional propensity score has important benefits in large-scale pharmacoepidemiologic studies, we recommend omitting the prevalence-based empirical identification of candidate covariates. PMID:25866189

  19. Propensity Score-Based Approaches to Confounding by Indication in Individual Patient Data Meta-Analysis: Non-Standardized Treatment for Multidrug Resistant Tuberculosis

    PubMed Central

    Fox, Gregory J.; Benedetti, Andrea; Mitnick, Carole D.; Pai, Madhukar; Menzies, Dick

    2016-01-01

    Background In the absence of randomized clinical trials, meta-analysis of individual patient data (IPD) from observational studies may provide the most accurate effect estimates for an intervention. However, confounding by indication remains an important concern that can be addressed by incorporating individual patient covariates in different ways. We compared different analytic approaches to account for confounding in IPD from patients treated for multi-drug resistant tuberculosis (MDR-TB). Methods Two antibiotic classes were evaluated, fluoroquinolones—considered the cornerstone of effective MDR-TB treatment—and macrolides, which are known to be safe, yet are ineffective in vitro. The primary outcome was treatment success against treatment failure, relapse or death. Effect estimates were obtained using multivariable and propensity-score based approaches. Results Fluoroquinolone antibiotics were used in 28 included studies, within which 6,612 patients received a fluoroquinolone and 723 patients did not. Macrolides were used in 15 included studies, within which 459 patients received this class of antibiotics and 3,670 did not. Both standard multivariable regression and propensity score-based methods resulted in similar effect estimates for early and late generation fluoroquinolones, while macrolide antibiotics use was associated with reduced treatment success. Conclusions In this individual patient data meta-analysis, standard multivariable and propensity-score based methods of adjusting for individual patient covariates for observational studies yielded produced similar effect estimates. Even when adjustment is made for potential confounding, interpretation of adjusted estimates must still consider the potential for residual bias. PMID:27022741

  20. Sensitivity analysis for unmeasured confounding in principal stratification settings with binary variables

    PubMed Central

    Schwartz, Scott; Li, Fan; Reiter, Jerome P.

    2016-01-01

    Within causal inference, principal stratification (PS) is a popular approach for dealing with intermediate variables, that is, variables affected by treatment that also potentially affect the response. However, when there exists unmeasured confounding in the treatment arms—as can happen in observational studies—causal estimands resulting from PS analyses can be biased. We identify the various pathways of confounding present in PS contexts and their effects for PS inference. We present model-based approaches for assessing the sensitivity of complier average causal effect estimates to unmeasured confounding in the setting of binary treatments, binary intermediate variables, and binary outcomes. These same approaches can be used to assess sensitivity to unknown direct effects of treatments on outcomes because, as we show, direct effects are operationally equivalent to one of the pathways of unmeasured confounding. We illustrate the methodology using a randomized study with artificially introduced confounding and a sensitivity analysis for an observational study of the effects of physical activity and body mass index on cardiovascular disease. PMID:22362635

  1. Understanding Confounding Effects in Linguistic Coordination: An Information-Theoretic Approach

    PubMed Central

    Gao, Shuyang; Ver Steeg, Greg; Galstyan, Aram

    2015-01-01

    We suggest an information-theoretic approach for measuring stylistic coordination in dialogues. The proposed measure has a simple predictive interpretation and can account for various confounding factors through proper conditioning. We revisit some of the previous studies that reported strong signatures of stylistic accommodation, and find that a significant part of the observed coordination can be attributed to a simple confounding effect—length coordination. Specifically, longer utterances tend to be followed by longer responses, which gives rise to spurious correlations in the other stylistic features. We propose a test to distinguish correlations in length due to contextual factors (topic of conversation, user verbosity, etc.) and turn-by-turn coordination. We also suggest a test to identify whether stylistic coordination persists even after accounting for length coordination and contextual factors. PMID:26115446

  2. EVALUATING COSTS WITH UNMEASURED CONFOUNDING: A SENSITIVITY ANALYSIS FOR THE TREATMENT EFFECT.

    PubMed

    Handorf, Elizabeth A; Bekelman, Justin E; Heitjan, Daniel F; Mitra, Nandita

    2013-01-01

    Estimates of the effects of treatment on cost from observational studies are subject to bias if there are unmeasured confounders. It is therefore advisable in practice to assess the potential magnitude of such biases. We derive a general adjustment formula for loglinear models of mean cost and explore special cases under plausible assumptions about the distribution of the unmeasured confounder. We assess the performance of the adjustment by simulation, in particular, examining robustness to a key assumption of conditional independence between the unmeasured and measured covariates given the treatment indicator. We apply our method to SEER-Medicare cost data for a stage II/III muscle-invasive bladder cancer cohort. We evaluate the costs for radical cystectomy vs. combined radiation/chemotherapy, and find that the significance of the treatment effect is sensitive to plausible unmeasured Bernoulli, Poisson and Gamma confounders. PMID:24587844

  3. Restricted spatial regression in practice: Geostatistical models, confounding, and robustness under model misspecification

    USGS Publications Warehouse

    Hanks, Ephraim M.; Schliep, Erin M.; Hooten, Mevin B.; Hoeting, Jennifer A.

    2015-01-01

    In spatial generalized linear mixed models (SGLMMs), covariates that are spatially smooth are often collinear with spatially smooth random effects. This phenomenon is known as spatial confounding and has been studied primarily in the case where the spatial support of the process being studied is discrete (e.g., areal spatial data). In this case, the most common approach suggested is restricted spatial regression (RSR) in which the spatial random effects are constrained to be orthogonal to the fixed effects. We consider spatial confounding and RSR in the geostatistical (continuous spatial support) setting. We show that RSR provides computational benefits relative to the confounded SGLMM, but that Bayesian credible intervals under RSR can be inappropriately narrow under model misspecification. We propose a posterior predictive approach to alleviating this potential problem and discuss the appropriateness of RSR in a variety of situations. We illustrate RSR and SGLMM approaches through simulation studies and an analysis of malaria frequencies in The Gambia, Africa.

  4. EVALUATING COSTS WITH UNMEASURED CONFOUNDING: A SENSITIVITY ANALYSIS FOR THE TREATMENT EFFECT

    PubMed Central

    Handorf, Elizabeth A.; Bekelman, Justin E.; Heitjan, Daniel F.; Mitra, Nandita

    2014-01-01

    Estimates of the effects of treatment on cost from observational studies are subject to bias if there are unmeasured confounders. It is therefore advisable in practice to assess the potential magnitude of such biases. We derive a general adjustment formula for loglinear models of mean cost and explore special cases under plausible assumptions about the distribution of the unmeasured confounder. We assess the performance of the adjustment by simulation, in particular, examining robustness to a key assumption of conditional independence between the unmeasured and measured covariates given the treatment indicator. We apply our method to SEER-Medicare cost data for a stage II/III muscle-invasive bladder cancer cohort. We evaluate the costs for radical cystectomy vs. combined radiation/chemotherapy, and find that the significance of the treatment effect is sensitive to plausible unmeasured Bernoulli, Poisson and Gamma confounders. PMID:24587844

  5. Identity and Epistemic Emotions during Knowledge Revision: A Potential Account for the Backfire Effect

    ERIC Educational Resources Information Center

    Trevors, Gregory J.; Muis, Krista R.; Pekrun, Reinhard; Sinatra, Gale M.; Winne, Philip H.

    2016-01-01

    Recent research has shown that for some topics, messages to refute and revise misconceptions may backfire. The current research offers one possible account for this backfire effect (i.e., the ironic strengthening of belief in erroneous information after an attempted refutation) from an educational psychology perspective and examines whether…

  6. Environmental confounding in gene-environment interaction studies.

    PubMed

    Vanderweele, Tyler J; Ko, Yi-An; Mukherjee, Bhramar

    2013-07-01

    We show that, in the presence of uncontrolled environmental confounding, joint tests for the presence of a main genetic effect and gene-environment interaction will be biased if the genetic and environmental factors are correlated, even if there is no effect of either the genetic factor or the environmental factor on the disease. When environmental confounding is ignored, such tests will in fact reject the joint null of no genetic effect with a probability that tends to 1 as the sample size increases. This problem with the joint test vanishes under gene-environment independence, but it still persists if estimating the gene-environment interaction parameter itself is of interest. Uncontrolled environmental confounding will bias estimates of gene-environment interaction parameters even under gene-environment independence, but it will not do so if the unmeasured confounding variable itself does not interact with the genetic factor. Under gene-environment independence, if the interaction parameter without controlling for the environmental confounder is nonzero, then there is gene-environment interaction either between the genetic factor and the environmental factor of interest or between the genetic factor and the unmeasured environmental confounder. We evaluate several recently proposed joint tests in a simulation study and discuss the implications of these results for the conduct of gene-environment interaction studies.

  7. Comorbidity of intellectual disability confounds ascertainment of autism: implications for genetic diagnosis.

    PubMed

    Polyak, Andrew; Kubina, Richard M; Girirajan, Santhosh

    2015-10-01

    While recent studies suggest a converging role for genetic factors towards risk for nosologically distinct disorders including autism, intellectual disability (ID), and epilepsy, current estimates of autism prevalence fail to take into account the impact of comorbidity of these disorders on autism diagnosis. We aimed to assess the effect of comorbidity on the diagnosis and prevalence of autism by analyzing 11 years (2000-2010) of special education enrollment data on approximately 6.2 million children per year. We found a 331% increase in the prevalence of autism from 2000 to 2010 within special education, potentially due to a diagnostic recategorization from frequently comorbid features such as ID. The decrease in ID prevalence equaled an average of 64.2% of the increase of autism prevalence for children aged 3-18 years. The proportion of ID cases potentially undergoing recategorization to autism was higher (P = 0.007) among older children (75%) than younger children (48%). Some US states showed significant negative correlations between the prevalence of autism compared to that of ID while others did not, suggesting state-specific health policy to be a major factor in categorizing autism. Further, a high frequency of autistic features was observed when individuals with classically defined genetic syndromes were evaluated for autism using standardized instruments. Our results suggest that current ascertainment practices are based on a single facet of autism-specific clinical features and do not consider associated comorbidities that may confound diagnosis. Longitudinal studies with detailed phenotyping and deep molecular genetic analyses are necessary to completely understand the cause of this complex disorder.

  8. Limitations of individual causal models, causal graphs, and ignorability assumptions, as illustrated by random confounding and design unfaithfulness.

    PubMed

    Greenland, Sander; Mansournia, Mohammad Ali

    2015-10-01

    We describe how ordinary interpretations of causal models and causal graphs fail to capture important distinctions among ignorable allocation mechanisms for subject selection or allocation. We illustrate these limitations in the case of random confounding and designs that prevent such confounding. In many experimental designs individual treatment allocations are dependent, and explicit population models are needed to show this dependency. In particular, certain designs impose unfaithful covariate-treatment distributions to prevent random confounding, yet ordinary causal graphs cannot discriminate between these unconfounded designs and confounded studies. Causal models for populations are better suited for displaying these phenomena than are individual-level models, because they allow representation of allocation dependencies as well as outcome dependencies across individuals. Nonetheless, even with this extension, ordinary graphical models still fail to capture distinctions between hypothetical superpopulations (sampling distributions) and observed populations (actual distributions), although potential-outcome models can be adapted to show these distinctions and their consequences.

  9. Methodological problems with population cancer studies: The forgotten confounding factors

    PubMed Central

    Blaylock, Russell L.

    2015-01-01

    Among clinical physicians it is the population study that is considered to be the “gold standard” of medical evidence concerning acceptable treatments. As new information comes to light concerning the many variables and confounding factors that can affect such studies, many older studies lose much of their original impact. While newer population studies take into consideration a far greater number of confounding factors many are still omitted and a number of these omitted factors can have profound effects on interpretation and validity of the study. In this editorial, I will discuss some of the omitted confounding factors and demonstrate how they can alter the interpretation of these papers and their clinical application. PMID:26097772

  10. Rigid Response in an Age of Accountability: The Potential of Leadership and Trust

    ERIC Educational Resources Information Center

    Daly, Alan J.

    2009-01-01

    Purpose: The No Child Left Behind Act laudably brings social justice and equity issues to the forefront; however, the act's threat- and sanction-driven methods are not only increasing stress levels but potentially causing a rigid response, especially in the growing population of schools labeled "program improvement" (PI). Specifically,…

  11. Eliminating a Confounding Factor in Power Law Parameter Interpretation

    NASA Astrophysics Data System (ADS)

    Karst, N.; Dralle, D.; Thompson, S. E.

    2015-12-01

    Power law models of the form y = -axb are used to represent a wide range of phenomena in the physical, biological and social sciences. Power laws are well known to display a "scale-free property", meaning that the value of the exponent b is independent of the unit of measurement (the "scale") of the state variable x. While this makes estimation of the exponent robust, it raises significant estimation challenges for the linear multiplier a. Specifically, if both the multiplier a and exponent b are allowed to vary when undertaking an empirical fitting procedure, then physical units used to measure x induce a formal (i.e., entirely nonphysical) dependence between a and b, because the fitted value of a will contain a (potentially large) multiplicative factor that varies depending on the scale of x. This is problematic for two reasons: (i) if a is to be empirically estimated, but admits a physical interpretation, then the scale-dependent factor can confound the physically meaningful value (ii) the formal relationship between a and b due to the scaling of the relationship obscures any true relationship between the parameters and could motivate a spurious interpretation of their co-variation. To correct this issue, we present a technique to remove the formal correlation between a and b, and demonstrate an application of the technique in the context of streamflow recession analysis, where the falling limb of the hydrograph is modeled using a simple power law relationship, dq/dt = -aqb. Following the decorrelation of (a, b) recession parameter pairs, physically intuitive seasonal patterns, greatly obscured in the original data, are clearly found.

  12. Downward relativistic potential step and phenomenological account of Bohmian trajectories of the Klein paradox

    NASA Astrophysics Data System (ADS)

    Razavi, M.; Mollai, M.; Jami, S.; Ahanj, A.

    2016-09-01

    The Dirac equation has been applied to fermions scattering from the downward potential step. The results show that some particles do not fall off the edge of the step and reflect. Then, based on the de Broglie-Bohm interpretation of quantum mechanics (Bohmian mechanics) and Bohmian trajectories we have resolved the problem. Lastly, a phenomenological study of the Bohmian trajectory of the Klein paradox has been discussed.

  13. Assessing residual hydropower potential of the La Plata Basin accounting for future user demands

    NASA Astrophysics Data System (ADS)

    Popescu, I.; Brandimarte, L.; Perera, M. S. U.; Peviani, M.

    2012-04-01

    La Plata Basin is shared by five countries (Argentina, Bolivia, Brazil, Paraguay and Uruguay), which are having fast growing economies in South America. These countries need energy for their sustainable development; hence hydropower can play a very important role as a renewable clean source of energy. This paper presents an analysis of the current hydropower production and electricity demand in La Plata Basin (LPB) and makes an analysis of the maximum and residual hydropower potential of the basin for a horizon of 30 yr (i.e. year 2040). Current hydropower production is estimated based on historic available data while future energy production is deduced from the maximum available water in the catchment, whereas electricity demand is assessed by correlating existing electricity demand with the estimated population growth and economic development. The maximum and residual hydropower potential of the basin, were assessed for the mean annual flows of the present hydrological regime (1970-2000) and topographical characteristics of the area. Computations were performed using an integrated GIS environment called Vapidro-Aste released by the Research on Energy System (Italy). The residual hydropower potential of the basin is computed considering that first the water supply needs for population, industry and agriculture are served and than hydropower energy is produced. The calculated hydropower production is found to be approximately half of the estimated electricity demand, which shows that there is a need to look for other sources of energy in the future.

  14. Assessing residual hydropower potential of the La Plata Basin accounting for future user demands

    NASA Astrophysics Data System (ADS)

    Popescu, I.; Brandimarte, L.; Perera, M. S. U.; Peviani, M.

    2012-08-01

    La Plata Basin is shared by five countries (Argentina, Bolivia, Brazil, Paraguay and Uruguay), which have fast growing economies in South America. These countries need energy for their sustainable development; hence, hydropower can play a very important role as a renewable clean source of energy. This paper presents an analysis of the current hydropower production and electricity demand in La Plata Basin (LPB), and it analyses the maximum and residual hydropower potential of the basin for a horizon of 30 yr (i.e. year 2040). Current hydropower production is estimated based on historical available data, while future energy production is deduced from the available water in the catchment (estimated based on measured hydrographs of the past years), whereas electricity demand is assessed by correlating existing electricity demand with the estimated population growth and economic development. The maximum and residual hydropower potential of the basin were assessed for the mean annual flows of the present hydrological regime (1970-2000) and topographical characteristics of the area. Computations were performed using an integrated GIS environment called VAPIDRO-ASTE released by the Research on Energy System (Italy). The residual hydropower potential of the basin is computed considering first that the water supply needs for population, industry and agriculture are served, and then hydropower energy is produced. The calculated hydropower production is found to be approximately half of the estimated electricity demand, which shows that there is a need to look for other sources of energy in the future.

  15. Consistent accounting of steric effects for prediction of streaming potential in narrow confinements

    NASA Astrophysics Data System (ADS)

    Chakraborty, Jeevanjyoti; Dey, Ranabir; Chakraborty, Suman

    2012-12-01

    The traditional modeling framework for determining streaming potential, when taking into consideration finite size effects, suffers from an oversight in that while the model incorporates the size effects in the ion distribution profiles, it neglects these very same effects in the flux contributions, even though diffusivities are intrinsically linked with ionic friction, which again depends on the size of the ions. This oversight may lead to inconsistent quantitative estimates through ad hoc consideration of diffusivity values, apparently independent of the specific size of the ions, which nevertheless determines the ionic profiles. We remedy this theoretical inconsistency by expressing the diffusivity in terms of the ionic radius and investigate the consequences of such a description of the diffusivity-dependent flux, consistent with the ionic distribution profiles, on streaming potential mediated flow predictions. Additionally, we consider the effects of “charge induced thickening” so that both viscosity and diffusivity are expressed as spatially varying functions. As an unintuitive implication, we also show that calculation of nonzero values of streaming potential under the purview of classical Boltzmann distributions, which consider ions to be pointlike charges, is itself a theoretical inconsistency. We believe that the simple framework presented in this paper will pave the way for more sophisticated modeling efforts in the future.

  16. The Impact of Individual Learning Accounts: A Study of the Early and Potential Impact of Individual Learning Accounts on Learning Providers and Learning. Research Report.

    ERIC Educational Resources Information Center

    Gray, Michael; Peters, Jane; Fletcher, Mick; Kirk, Gordon

    The impact of individual learning accounts (ILAs) on the success of learners in post-16 education sector in the United Kingdom was explored through an examination of available research on ILAs. The following were among the study's 12 messages for providers, the Department for Education and Skills, and the Individual Learning Account Centre: (1)…

  17. Causal diagrams and multivariate analysis III: confound it!

    PubMed

    Jupiter, Daniel C

    2015-01-01

    This commentary concludes my series concerning inclusion of variables in multivariate analyses. We take up the issues of confounding and effect modification and summarize the work we have thus far done. Finally, we provide a rough algorithm to help guide us through the maze of possibilities that we have outlined.

  18. The Threshold of Embedded M Collider Bias and Confounding Bias

    ERIC Educational Resources Information Center

    Kelcey, Benjamin; Carlisle, Joanne

    2011-01-01

    Of particular import to this study, is collider bias originating from stratification on retreatment variables forming an embedded M or bowtie structural design. That is, rather than assume an M structural design which suggests that "X" is a collider but not a confounder, the authors adopt what they consider to be a more reasonable position and…

  19. Wind turbines and idiopathic symptoms: The confounding effect of concurrent environmental exposures.

    PubMed

    Blanes-Vidal, Victoria; Schwartz, Joel

    2016-01-01

    Whether or not wind turbines pose a risk to human health is a matter of heated debate. Personal reactions to other environmental exposures occurring in the same settings as wind turbines may be responsible of the reported symptoms. However, these have not been accounted for in previous studies. We investigated whether there is an association between residential proximity to wind turbines and idiopathic symptoms, after controlling for personal reactions to other environmental co-exposures. We assessed wind turbine exposures in 454 residences as the distance to the closest wind turbine (Dw) and number of wind turbines <1000m (Nw1000). Information on symptoms, demographics and personal reactions to exposures was obtained by a blind questionnaire. We identified confounders using confounders' selection criteria and used adjusted logistic regression models to estimate associations. When controlling only for socio-demographic characteristics, log10Dw was associated with "unnatural fatigue" (ORadj=0.38, 95%CI=0.15-1.00) and "difficulty concentrating" (ORadj=0.26, 95%CI=0.08-0.83) and Nw1000 was associated with "unnatural fatigue" (ORadj=1.35, 95%CI=1.07-1.70) and "headache" (ORadj=1.26, 95%CI=1.00-1.58). After controlling for personal reactions to noise from sources different from wind turbines and agricultural odor exposure, we did not observe a significant relationship between residential proximity to wind turbines and symptoms and the parameter estimates were attenuated toward zero. Wind turbines-health associations can be confounded by personal reactions to other environmental co-exposures. Isolated associations reported in the literature may be due to confounding bias.

  20. Wind turbines and idiopathic symptoms: The confounding effect of concurrent environmental exposures.

    PubMed

    Blanes-Vidal, Victoria; Schwartz, Joel

    2016-01-01

    Whether or not wind turbines pose a risk to human health is a matter of heated debate. Personal reactions to other environmental exposures occurring in the same settings as wind turbines may be responsible of the reported symptoms. However, these have not been accounted for in previous studies. We investigated whether there is an association between residential proximity to wind turbines and idiopathic symptoms, after controlling for personal reactions to other environmental co-exposures. We assessed wind turbine exposures in 454 residences as the distance to the closest wind turbine (Dw) and number of wind turbines <1000m (Nw1000). Information on symptoms, demographics and personal reactions to exposures was obtained by a blind questionnaire. We identified confounders using confounders' selection criteria and used adjusted logistic regression models to estimate associations. When controlling only for socio-demographic characteristics, log10Dw was associated with "unnatural fatigue" (ORadj=0.38, 95%CI=0.15-1.00) and "difficulty concentrating" (ORadj=0.26, 95%CI=0.08-0.83) and Nw1000 was associated with "unnatural fatigue" (ORadj=1.35, 95%CI=1.07-1.70) and "headache" (ORadj=1.26, 95%CI=1.00-1.58). After controlling for personal reactions to noise from sources different from wind turbines and agricultural odor exposure, we did not observe a significant relationship between residential proximity to wind turbines and symptoms and the parameter estimates were attenuated toward zero. Wind turbines-health associations can be confounded by personal reactions to other environmental co-exposures. Isolated associations reported in the literature may be due to confounding bias. PMID:27046778

  1. Subliminal psychodynamic activation: an experiment controlling for major possible confounding influences outlined by Fudin.

    PubMed

    Gustafson, R; Källmén, H

    1991-08-01

    40 and 48 subjects participated in two separate experiments aimed at reproducing the subliminal psychodynamic activation (SPA) phenomenon and taking into account the major methodological critique by Fudin (1986, 1990). Subjects were first exposed either to a full or one of all possible partial symbiotic messages and then to their anagram equivalents. Confounding and irrelevant influences were controlled; the results indicate that only the full symbiotic message improved motor performance. This strongly suggests that subjects encode the meaning of the full message and supports an interpretation in terms of an alleviation of an internal symbiotic conflict leading to a state of calmness conducive to improved motor performance. PMID:1945681

  2. External Adjustment Sensitivity Analysis for Unmeasured Confounding: An Application to Coronary Stent Outcomes, Pennsylvania 2004–2008

    PubMed Central

    Huesch, Marco D

    2013-01-01

    Background Assessing the real-world comparative effectiveness of common interventions is challenged by unmeasured confounding. Objective To determine whether the mortality benefit shown for drug-eluting stents (DES) over bare metal stents (BMS) in observational studies persists after controls for/tests for confounding. Data Sources/Study Setting Retrospective observational study involving 38,019 patients, 65 years or older admitted for an index percutaneous coronary intervention receiving DES or BMS in Pennsylvania in 2004–2005 followed up for death through 3 years. Study Design Analysis was at the patient level. Mortality was analyzed with Cox proportional hazards models allowing for stratification by disease severity or DES use propensity, accounting for clustering of patients. Instrumental variables analysis used lagged physician stent usage to proxy for the focal stent type decision. A method originating in work by Cornfield and others in 1954 and popularized by Greenland in 1996 was used to assess robustness to confounding. Principal Findings DES was associated with a significantly lower adjusted risk of death at 3 years in Cox and in instrumented analyses. An implausibly strong hypothetical unobserved confounder would be required to fully explain these results. Conclusions Confounding by indication can bias observational studies. No strong evidence of such selection biases was found in the reduced risk of death among elderly patients receiving DES instead of BMS in a Pennsylvanian state-wide population. PMID:23206261

  3. Threats to internal validity in exercise science: a review of overlooked confounding variables.

    PubMed

    Halperin, Israel; Pyne, David B; Martin, David T

    2015-10-01

    Internal validity refers to the degree of control exerted over potential confounding variables to reduce alternative explanations for the effects of various treatments. In exercise and sports-science research and routine testing, internal validity is commonly achieved by controlling variables such as exercise and warm-up protocols, prior training, nutritional intake before testing, ambient temperature, time of testing, hours of sleep, age, and gender. However, a number of other potential confounding variables often do not receive adequate attention in sports physiology and performance research. These confounding variables include instructions on how to perform the test, volume and frequency of verbal encouragement, knowledge of exercise endpoint, number and gender of observers in the room, influence of music played before and during testing, and the effects of mental fatigue on performance. In this review the authors discuss these variables in relation to common testing environments in exercise and sports science and present some recommendations with the goal of reducing possible threats to internal validity.

  4. Confounding of the Comparative Safety of Prenatal Opioid Agonist Therapy

    PubMed Central

    Brogly, Susan B; Hahn, Kristen A; Diaz, Sonia Hernandez; Werler, Martha

    2016-01-01

    Prenatal opioid agonist therapy with methadone or buprenorphine prevents maternal illicit opioid use and withdrawal and improves pregnancy outcomes compared to heroin use alone. Historically, methadone has been the first-line opioid agonist therapy for pregnant opioid dependent women; in recent years buprenorphine has become first-line treatment for some opioid dependent pregnant women. While there is some evidence of better outcomes in neonates exposed to buprenorphine vs. methadone, the effect of confounding from differences in women who use buprenorphine and methadone has not been carefully examined in most studies. This review explores mechanisms by which confounding can arise in measuring associations between prenatal buprenorphine vs. methadone exposure on neonatal outcomes using a graphical approach, directed acyclic graphs. The goal of this paper is to facilitate better understanding of the factors influencing neonatal abstinence syndrome and accurate assessment of the comparative safety of opioid agonist therapies on the neonate. PMID:27547489

  5. Air pollutants and health outcomes: Assessment of confounding by influenza

    NASA Astrophysics Data System (ADS)

    Thach, Thuan-Quoc; Wong, Chit-Ming; Chan, King-Pan; Chau, Yuen-Kwan; Neil Thomas, G.; Ou, Chun-Quan; Yang, Lin; Peiris, Joseph S. M.; Lam, Tai-Hing; Hedley, Anthony J.

    2010-04-01

    We assessed confounding of associations between short-term effects of air pollution and health outcomes by influenza using Hong Kong mortality and hospitalization data for 1996-2002. Three measures of influenza were defined: (i) intensity: weekly proportion of positive influenza viruses, (ii) epidemic: weekly number of positive influenza viruses ≥4% of the annual number for ≥2 consecutive weeks, and (iii) predominance: an epidemic period with co-circulation of respiratory syncytial virus <2% of the annual positive isolates for ≥2 consecutive weeks. We examined effects of influenza on associations between nitrogen dioxide (NO 2), sulfur dioxide (SO 2), particulate matter with aerodynamic diameter ≤10 μm (PM 10) and ozone (O 3) and health outcomes including all natural causes mortality, cardiorespiratory mortality and hospitalization. Generalized additive Poisson regression model with natural cubic splines was fitted to control for time-varying covariates to estimate air pollution health effects. Confounding with influenza was assessed using an absolute difference of >0.1% between unadjusted and adjusted excess risks (ER%). Without adjustment, pollutants were associated with positive ER% for all health outcomes except asthma and stroke hospitalization with SO 2 and stroke hospitalization with O 3. Following adjustment, changes in ER% for all pollutants were <0.1% for all natural causes mortality, but >0.1% for mortality from stroke with NO 2 and SO 2, cardiac or heart disease with NO 2, PM 10 and O 3, lower respiratory infections with NO 2 and O 3 and mortality from chronic obstructive pulmonary disease with all pollutants. Changes >0.1% were seen for acute respiratory disease hospitalization with NO 2, SO 2 and O 3 and acute lower respiratory infections hospitalization with PM 10. Generally, influenza does not confound the observed associations of air pollutants with all natural causes mortality and cardiovascular hospitalization, but for some pollutants

  6. Prenatal Paracetamol Exposure and Wheezing in Childhood: Causation or Confounding?

    PubMed Central

    Migliore, Enrica; Zugna, Daniela; Galassi, Claudia; Merletti, Franco; Gagliardi, Luigi; Rasero, Laura; Trevisan, Morena; Rusconi, Franca; Richiardi, Lorenzo

    2015-01-01

    Background Several studies have reported an increased risk of wheezing in the children of mothers who used paracetamol during pregnancy. We evaluated to what extent this association is explained by confounding. Methods We investigated the association between maternal paracetamol use in the first and third trimester of pregnancy and ever wheezing or recurrent wheezing/asthma in infants in the NINFEA cohort study. Risks ratios (RR) and 95% confidence intervals (CI) were estimated after adjustment for confounders, including maternal infections and antibiotic use during pregnancy. Results The prevalence of maternal paracetamol use was 30.6% during the first and 36.7% during the third trimester of pregnancy. The prevalence of ever wheezing and recurrent wheezing/asthma was 16.9% and 5.6%, respectively. After full adjustment, the RR for ever wheezing decreased from 1.25 [1.07–1.47] to 1.10 [0.94–1.30] in the first, and from 1.26 [1.08–1.47] to 1.10 [0.93–1.29] in the third trimester. A similar pattern was observed for recurrent wheezing/asthma. Duration of maternal paracetamol use was not associated with either outcome. Further analyses on paracetamol use for three non-infectious disorders (sciatica, migraine, and headache) revealed no increased risk of wheezing in children. Conclusion The association between maternal paracetamol use during pregnancy and infant wheezing is mainly, if not completely explained by confounding. PMID:26305473

  7. Possible confounding factors on cerebral diffusion tensor imaging measurements

    PubMed Central

    Nenonen, Miina; Hakulinen, Ullamari; Brander, Antti; Ohman, Juha; Dastidar, Prasun

    2015-01-01

    Background Diffusion tensor imaging (DTI) is prone to numerous systemic confounding factors that should be acknowledged to avoid false conclusions. Purpose To investigate the possible effects of age, gender, smoking, alcohol consumption, and education on cerebral DTI parameters in a generally healthy homogenous sample with no neurological or psychiatric diseases. Material and Methods Forty (n = 40) subjects (mean age, 40.3 years; SD, 12.3) underwent brain DTI with 3 T magnetic resonance imaging (MRI). At enrolment, all the subjects were interviewed with respect to general health, education, history of smoking, and alcohol consumption. Studied DTI parameters included: (i) fractional anisotropy (FA); and (ii) apparent diffusion coefficient (ADC). Region-of-interest (ROI)-based measurements were estimated at 13 anatomical locations bilaterally on the axial images, except for the corpus callosum in which the ROIs were placed on the sagittal images. Circular ROI measurements were mainly used. Freehand ROI method was used with the forceps minor, uncinate fasciculus, and thalamus. Intra-observer variability and repeatability were assessed. Results The most consistent finding was that aging decreased FA values in the frontal brain regions. Regarding the other confounding factors, the results were discontinuous and no concrete conclusions could be drawn from these findings. In general, intra-observer repeatability of the DTI measurement was considered relatively good. Conclusion Age should be noted as considerable confounding factors in ROI-based DTI analysis. More research on the effects of gender, smoking, alcohol consumption, and education is needed. PMID:25793107

  8. Rainfall and temperatures changes have confounding impacts on Phytophthora cinnamomi occurrence risk in the southwestern USA under climate change scenarios.

    PubMed

    Thompson, Sally E; Levin, Simon; Rodriguez-Iturbe, Ignacio

    2014-04-01

    Global change will simultaneously impact many aspects of climate, with the potential to exacerbate the risks posed by plant pathogens to agriculture and the natural environment; yet, most studies that explore climate impacts on plant pathogen ranges consider individual climatic factors separately. In this study, we adopt a stochastic modeling approach to address multiple pathways by which climate can constrain the range of the generalist plant pathogen Phytophthora cinnamomi (Pc): through changing winter soil temperatures affecting pathogen survival; spring soil temperatures and thus pathogen metabolic rates; and changing spring soil moisture conditions and thus pathogen growth rates through host root systems. We apply this model to the southwestern USA for contemporary and plausible future climate scenarios and evaluate the changes in the potential range of Pc. The results indicate that the plausible range of this pathogen in the southwestern USA extends over approximately 200,000 km(2) under contemporary conditions. While warming temperatures as projected by the IPCC A2 and B1 emissions scenarios greatly expand the range over which the pathogen can survive winter, projected reductions in spring rainfall reduce its feasible habitat, leading to spatially complex patterns of changing risk. The study demonstrates that temperature and rainfall changes associated with possible climate futures in the southwestern USA have confounding impacts on the range of Pc, suggesting that projections of future pathogen dynamics and ranges should account for multiple pathways of climate-pathogen interaction.

  9. Mediation Analysis With Intermediate Confounding: Structural Equation Modeling Viewed Through the Causal Inference Lens

    PubMed Central

    De Stavola, Bianca L.; Daniel, Rhian M.; Ploubidis, George B.; Micali, Nadia

    2015-01-01

    The study of mediation has a long tradition in the social sciences and a relatively more recent one in epidemiology. The first school is linked to path analysis and structural equation models (SEMs), while the second is related mostly to methods developed within the potential outcomes approach to causal inference. By giving model-free definitions of direct and indirect effects and clear assumptions for their identification, the latter school has formalized notions intuitively developed in the former and has greatly increased the flexibility of the models involved. However, through its predominant focus on nonparametric identification, the causal inference approach to effect decomposition via natural effects is limited to settings that exclude intermediate confounders. Such confounders are naturally dealt with (albeit with the caveats of informality and modeling inflexibility) in the SEM framework. Therefore, it seems pertinent to revisit SEMs with intermediate confounders, armed with the formal definitions and (parametric) identification assumptions from causal inference. Here we investigate: 1) how identification assumptions affect the specification of SEMs, 2) whether the more restrictive SEM assumptions can be relaxed, and 3) whether existing sensitivity analyses can be extended to this setting. Data from the Avon Longitudinal Study of Parents and Children (1990–2005) are used for illustration. PMID:25504026

  10. Evaluating Public Health Interventions: 3. The Two-Stage Design for Confounding Bias Reduction—Having Your Cake and Eating It Two

    PubMed Central

    Spiegelman, Donna; Rivera-Rodriguez, Claudia L.; Haneuse, Sebastien

    2016-01-01

    In public health evaluations, confounding bias in the estimate of the intervention effect will typically threaten the validity of the findings. It is a common misperception that the only way to avoid this bias is to measure detailed, high-quality data on potential confounders for every intervention participant, but this strategy for adjusting for confounding bias is often infeasible. Rather than ignoring confounding altogether, the two-phase design and analysis—in which detailed high-quality confounding data are obtained among a small subsample—can be considered. We describe the two-stage design and analysis approach, and illustrate its use in the evaluation of an intervention conducted in Dar es Salaam, Tanzania, of an enhanced community health worker program to improve antenatal care uptake. PMID:27285260

  11. Evaluating Public Health Interventions: 3. The Two-Stage Design for Confounding Bias Reduction-Having Your Cake and Eating It Two.

    PubMed

    Spiegelman, Donna; Rivera-Rodriguez, Claudia L; Haneuse, Sebastien

    2016-07-01

    In public health evaluations, confounding bias in the estimate of the intervention effect will typically threaten the validity of the findings. It is a common misperception that the only way to avoid this bias is to measure detailed, high-quality data on potential confounders for every intervention participant, but this strategy for adjusting for confounding bias is often infeasible. Rather than ignoring confounding altogether, the two-phase design and analysis-in which detailed high-quality confounding data are obtained among a small subsample-can be considered. We describe the two-stage design and analysis approach, and illustrate its use in the evaluation of an intervention conducted in Dar es Salaam, Tanzania, of an enhanced community health worker program to improve antenatal care uptake.

  12. An assessment of the possible extent of confounding in epidemiological studies of lung cancer risk among roofers

    SciTech Connect

    Mundt, D.J.; van Wijngaarden, E.; Mundt, K.A.

    2007-07-01

    We evaluated the likelihood and extent to which the observed increased risk of lung cancer may be due to confounding (a mixing of effects of multiple exposures) by co-exposure to other potential carcinogens present in roofing or to lifestyle variables. We conducted a review of the epidemiological and industrial hygiene literature of asphalt-exposed workers. Peer-reviewed epidemiological studies of asphalt fumes, related occupational exposures, and confounding factors were identified from MEDLINE (1966 early 2004). Industrial hygiene studies of asphalt workers were identified through MEDLINE, publicly available government documents, and asphalt industry documents. Using well established statistical methods, we quantified the extent to which lung cancer relative risk estimates among roofers reflect confounding from other exposures, using different prevalence and risk scenarios. The relative risk of lung cancer varied from 1.2 to 5.0 in 13 epidemiological studies of roofers; most studies reported a relative risk between 1.2 and 1.4. Smoking, asbestos and coal tar were the most likely confounders, but the prevalence of these factors varied over time. The results of the study indicate that much of the observed risk reported in epidemiological studies of cancer among roofers is well within the range of what may have resulted from confounding by reasonable and expected levels of smoking, asbestos or coal tar. This may be particularly true for those studies that did not adjust for these confounders and where the exposure was defined as employment in the roofing industry. In addition to poorly defined asphalt exposure, uncontrolled confounding cannot reliably be ruled out in studies of lung cancer among asphalt-exposed roofers. Therefore, it is not possible to conclude whether roofers are at increased risk of lung cancer due to asphalt exposure.

  13. A method for controlling complex confounding effects in the detection of adverse drug reactions using electronic health records

    PubMed Central

    Li, Ying; Salmasian, Hojjat; Vilar, Santiago; Chase, Herbert; Friedman, Carol; Wei, Ying

    2014-01-01

    Objective Electronic health records (EHRs) contain information to detect adverse drug reactions (ADRs), as they contain comprehensive clinical information. A major challenge of using comprehensive information involves confounding. We propose a novel data-driven method to identify ADR signals accurately by adjusting for confounders. Materials and methods We focused on two serious ADRs, rhabdomyolysis and pancreatitis, and used information in 264 155 unique patient records. We identified an ADR using established criteria, selected potential confounders, and then used penalized logistic regressions to estimate confounder-adjusted ADR associations. A reference standard was created to evaluate and compare the precision of the proposed method and four others. Results Precision was 83.3% for rhabdomyolysis and 60.8% for pancreatitis when using the proposed method, and we identified several drug safety signals that are interesting for further clinical review. Discussion The proposed method effectively estimated ADR associations after adjusting for confounders. A main cause of error was probably due to the nature of the dataset in that a substantial number of patients had a single visit only and, therefore, it was not possible to determine correctly the appropriate sequence of events for them. It is likely that performance will be improved with use of EHR data that contain more longitudinal records. Conclusions This data-driven method is effective in controlling for confounding, resulting in either a higher or similar precision when compared with four comparators, has the unique ability to provide insight into confounders for each specific medication–ADR pair, and can be easily adapted to other EHR systems. PMID:23907285

  14. Treatment Confounded Missingness: A Comparison of Methods for Addressing Censored or Truncated Data in School Reform Evaluations. CRESST Report 832

    ERIC Educational Resources Information Center

    Rickles, Jordan H.; Hansen, Mark; Wang, Jia

    2013-01-01

    In this paper we examine ways to conceptualize and address potential bias that can arise when the mechanism for missing outcome data is at least partially associated with treatment assignment, an issue we refer to as treatment confounded missingness (TCM). In discussing TCM, we bring together concepts from the methodological literature on missing…

  15. Identification of pim kinases as novel targets for PJ34 with confounding effects in PARP biology.

    PubMed

    Antolín, Albert A; Jalencas, Xavier; Yélamos, José; Mestres, Jordi

    2012-12-21

    Small molecules are widely used in chemical biology without complete knowledge of their target profile, at risk of deriving conclusions that ignore potential confounding effects from unknown off-target interactions. The prediction and further experimental confirmation of novel affinities for PJ34 on Pim1 (IC(50) = 3.7 μM) and Pim2 (IC(50) = 16 μM) serine/threonine kinases, together with their involvement in many of the processes relevant to PARP biology, questions the appropriateness of using PJ34 as a chemical tool to probe the biological role of PARP1 and PARP2 at the high micromolar concentrations applied in most studies. PMID:23025350

  16. Are We Missing Something Pertinent? A Bias Analysis of Unmeasured Confounding in the Firearm-Suicide Literature.

    PubMed

    Miller, M; Swanson, S A; Azrael, D

    2016-01-01

    Despite the magnitude and consistency of risk estimates in the peer-reviewed literature linking firearm availability and suicide, inferring causality has been questioned on the theoretical basis that existing studies may have failed to account for the possibility that members of households with firearms differ from members of households without firearms in important ways related to suicide risk. The current bias analysis directly addresses this concern by describing the salient characteristics that such an unmeasured confounder would need to possess in order to yield the associations between firearm availability and suicide observed in the literature when, in fact, the causal effect is null. Four US studies, published between 1992 and 2003, met our eligibility criteria. We find that any such unmeasured confounder would need to possess an untenable combination of characteristics, such as being not only 1) as potent a suicide risk factor as the psychiatric disorders most tightly linked to suicide (e.g., major depressive and substance use disorders) but also 2) an order of magnitude more imbalanced across households with versus without firearms than is any known risk factor. No such confounder has been found or even suggested. The current study strongly suggests that unmeasured confounding alone is unlikely to explain the association between firearms and suicide.

  17. Problems and the potential direction of reforms for the current individual medical savings accounts in the Chinese health care system.

    PubMed

    Kong, Xiangjin; Yang, Yang; Gong, Fuqing; Zhao, Mingjie

    2012-12-01

    Individual health savings accounts are an important part of the current basic medical insurance system for urban workers in China. Since 1998 when the system of personal medical insurance accounts was first implemented, there has been considerable controversy over its function and significance within different social communities. This paper analyzes the main problems in the practical implementation of individual medical insurance accounts and discusses the social and cultural foundations for the establishment of family health savings accounts from the perspective of Chinese Confucian familism. Accordingly, it addresses the direction of the reform and the development of the current system of individual health insurance accounts in China.

  18. Child welfare clients have higher risks for teenage childbirths: which are the major confounders?

    PubMed Central

    Vinnerljung, Bo; Hjern, Anders

    2016-01-01

    Background: Aiming to support effective social intervention strategies targeting high-risk groups for teenage motherhood, this study examined to what extent the elevated crude risks of teenage childbirth among child welfare groups were attributable to the uneven distribution of adverse individual and family background factors. Methods: Comprehensive longitudinal register data for more than 700 000 Swedish females born 1973–1989 (including around 29 000 child welfare clients) were analysed by means of binary logistic regression. The Karlson/Holm/Breen-method was used to decompose each confounding factor’s relative contribution to the difference between crude and adjusted odds ratios (ORs). Results: Elevated crude risks for teenage childbirth are to a large extent attributable to selection on observables. Girls’ school failure was the most potent confounder, accounting for 28–35% of the difference between crude and adjusted ORs. Conclusion: As in majority populations, girls’ school failure was a strong risk factor for teenage childbirth among former child welfare children. At least among pre-adolescents, promoting school performance among children in the child welfare system seems to be a viable intervention path. PMID:27085195

  19. Evaluation in medical education: A topical review of target parameters, data collection tools and confounding factors

    PubMed Central

    Schiekirka, Sarah; Feufel, Markus A.; Herrmann-Lingen, Christoph; Raupach, Tobias

    2015-01-01

    Background and objective: Evaluation is an integral part of education in German medical schools. According to the quality standards set by the German Society for Evaluation, evaluation tools must provide an accurate and fair appraisal of teaching quality. Thus, data collection tools must be highly reliable and valid. This review summarises the current literature on evaluation of medical education with regard to the possible dimensions of teaching quality, the psychometric properties of survey instruments and potential confounding factors. Methods: We searched Pubmed, PsycINFO and PSYNDEX for literature on evaluation in medical education and included studies published up until June 30, 2011 as well as articles identified in the “grey literature”. Results are presented as a narrative review. Results: We identified four dimensions of teaching quality: structure, process, teacher characteristics, and outcome. Student ratings are predominantly used to address the first three dimensions, and a number of reliable tools are available for this purpose. However, potential confounders of student ratings pose a threat to the validity of these instruments. Outcome is usually operationalised in terms of student performance on examinations, but methodological problems may limit the usability of these data for evaluation purposes. In addition, not all examinations at German medical schools meet current quality standards. Conclusion: The choice of tools for evaluating medical education should be guided by the dimension that is targeted by the evaluation. Likewise, evaluation results can only be interpreted within the context of the construct addressed by the data collection tool that was used as well as its specific confounding factors. PMID:26421003

  20. Moving toward implementation: the potential for accountable care organizations and private-public partnerships to advance active neighborhood design.

    PubMed

    Zusman, Edie E; Carr, Sara Jensen; Robinson, Judy; Kasirye, Olivia; Zell, Bonnie; Miller, William Jahmal; Duarte, Teri; Engel, Adrian B; Hernandez, Monica; Horton, Mark B; Williams, Frank

    2014-12-01

    The 2010 Affordable Care Act's (ACA) aims of lowering costs and improving quality of care will renew focus on preventive health strategies. This coincides with a trend in medicine to reconsider population health approaches as part of the standard curriculum. This intersection of new policy and educational climates presents a unique opportunity to reconsider traditional healthcare structures. This paper introduces and advances an alignment that few have considered. We propose that accountable care organizations (ACOs), which are expected to proliferate under the ACA, present the best opportunity to establish partnerships between healthcare, public health, and community-based organizations to achieve the legislation's goals. One example is encouraging daily physical activity via built environment interventions and programs, which is recommended by numerous groups. We highlight how nonprofit organizations in Sacramento, California have been able to leverage influence, capital, and policy to encourage design for active living, and how their work is coordinating with public health and healthcare initiatives. In conclusion, we critically examine potential barriers to the success of partnerships between ACOs and community organizations and encourage further exploration and evaluation.

  1. Moving toward implementation: the potential for accountable care organizations and private-public partnerships to advance active neighborhood design.

    PubMed

    Zusman, Edie E; Carr, Sara Jensen; Robinson, Judy; Kasirye, Olivia; Zell, Bonnie; Miller, William Jahmal; Duarte, Teri; Engel, Adrian B; Hernandez, Monica; Horton, Mark B; Williams, Frank

    2014-12-01

    The 2010 Affordable Care Act's (ACA) aims of lowering costs and improving quality of care will renew focus on preventive health strategies. This coincides with a trend in medicine to reconsider population health approaches as part of the standard curriculum. This intersection of new policy and educational climates presents a unique opportunity to reconsider traditional healthcare structures. This paper introduces and advances an alignment that few have considered. We propose that accountable care organizations (ACOs), which are expected to proliferate under the ACA, present the best opportunity to establish partnerships between healthcare, public health, and community-based organizations to achieve the legislation's goals. One example is encouraging daily physical activity via built environment interventions and programs, which is recommended by numerous groups. We highlight how nonprofit organizations in Sacramento, California have been able to leverage influence, capital, and policy to encourage design for active living, and how their work is coordinating with public health and healthcare initiatives. In conclusion, we critically examine potential barriers to the success of partnerships between ACOs and community organizations and encourage further exploration and evaluation. PMID:25117525

  2. The Problem of Confounding in Studies of the Effect of Maternal Drug Use on Pregnancy Outcome

    PubMed Central

    Källén, Bengt

    2012-01-01

    In most epidemilogical studies, the problem of confounding adds to the uncertainty in conclusions drawn. This is also true for studies on the effect of maternal drug use on birth defect risks. This paper describes various types of such confounders and discusses methods to identify and adjust for them. Such confounders can be found in maternal characteristics like age, parity, smoking, use of alcohol, and body mass index, subfertility, and previous pregnancies including previous birth of a malformed child, socioeconomy, race/ethnicity, or country of birth. Confounding by concomitant maternal drug use may occur. A geographical or seasonal confounding can exist. In rare instances, infant sex and multiple birth can appear as confounders. The most difficult problem to solve is often confounding by indication. The problem of confounding is less important for congenital malformations than for many other pregnancy outcomes. PMID:22190949

  3. Negative Confounding by Essential Fatty Acids in Methylmercury Neurotoxicity Associations

    PubMed Central

    Choi, Anna L; Mogensen, Ulla B.; Bjerve, Kristian S.; Debes, Frodi; Weihe, Pal; Grandjean, Philippe; Budtz-Jørgensen, Esben

    2014-01-01

    Background Methylmercury, a worldwide contaminant of fish and seafood, can cause adverse effects on the developing nervous system. However, long-chain n-3 polyunsaturated fatty acids in seafood provide beneficial effects on brain development. Negative confounding will likely result in underestimation of both mercury toxicity and nutrient benefits unless mutual adjustment is included in the analysis. Methods We examined these associations in 176 Faroese children, in whom prenatal methylmercury exposure was assessed from mercury concentrations in cord blood and maternal hair. The relative concentrations of fatty acids were determined in cord serum phospholipids. Neuropsychological performance in verbal, motor, attention, spatial, and memory functions was assessed at 7 years of age. Multiple regression and structural equation models (SEMs) were carried out to determine the confounder-adjusted associations with methylmercury exposure. Results A short delay recall (in percent change) in the California Verbal Learning Test (CVLT) was associated with a doubling of cord blood methylmercury (−18.9, 95% confidence interval [CI] = −36.3, −1.51). The association became stronger after the inclusion of fatty acid concentrations in the analysis (−22.0, 95% confidence interval [CI] = −39.4, −4.62). In structural equation models, poorer memory function (corresponding to a lower score in the learning trials and short delay recall in CVLT) was associated with a doubling of prenatal exposure to methylmercury after the inclusion of fatty acid concentrations in the analysis (−1.94, 95% CI = −3.39, −0.49). Conclusions Associations between prenatal exposure to methylmercury and neurobehavioral deficits in memory function at school age were strengthened after fatty acid adjustment, thus suggesting that n-3 fatty acids need to be included in analysis of similar studies to avoid underestimation of the associations with methylmercury exposure. PMID:24561639

  4. Is the inverse association between selenium and bladder cancer due to confounding by smoking?

    PubMed

    Beane Freeman, Laura E; Karagas, Margaret R; Baris, Dalsu; Schwenn, Molly; Johnson, Alison T; Colt, Joanne S; Jackson, Brian; Hosain, G M Monawar; Cantor, Kenneth P; Silverman, Debra T

    2015-04-01

    Selenium has been linked to a reduced risk of bladder cancer in some studies. Smoking, a well-established risk factor for bladder cancer, has been associated with lower selenium levels in the body. We investigated the selenium-bladder cancer association in subjects from Maine, New Hampshire, and Vermont in the New England Bladder Cancer Case-Control Study. At interview (2001-2005), participants provided information on a variety of factors, including a comprehensive smoking history, and submitted toenail samples, from which we measured selenium levels. We estimated odds ratios and 95% confidence intervals among 1,058 cases and 1,271 controls using logistic regression. After controlling for smoking, we saw no evidence of an association between selenium levels and bladder cancer (for fourth quartile vs. first quartile, odds ratio (OR) = 0.98, 95% confidence interval (CI): 0.77, 1.25). When results were restricted to regular smokers, there appeared to be an inverse association (OR = 0.76, 95% CI: 0.58, 0.99); however, when pack-years of smoking were considered, this association was attenuated (OR = 0.91, 95% CI: 0.68, 1.20), indicating potential confounding by smoking. Despite some reports of an inverse association between selenium and bladder cancer overall, our results, combined with an in-depth evaluation of other studies, suggested that confounding from smoking intensity or duration could explain this association. Our study highlights the need to carefully evaluate the confounding association of smoking in the selenium-bladder cancer association.

  5. The potential impact of accountable care organizations with respect to cost and quality with special attention to imaging.

    PubMed

    Mukherji, Suresh K

    2014-04-01

    An accountable care organization is a form of a managed care organization in which a group of networked health care providers, which may include hospitals, group practices, networks of practices, hospital-provider partnerships, or joint ventures, are accountable for the health care of a defined group of patients. Initial results of the institutions participating in CMS's Physician Group Demonstration Project did not demonstrate a substantial reduction in imaging that could be directly attributed to the accountable care organization model. However, the initial results suggest that incentive-based methodology appears to be successful for increasing compliance for measuring quality metrics. PMID:24332427

  6. Confounding Impacts of Iron Reduction on Arsenic Retention

    SciTech Connect

    Tufano, K.J.; Fendorf, S.

    2009-05-26

    A transition from oxidizing to reducing conditions has long been implicated to increase aqueous As concentrations, for which reductive dissolution of iron (hydr)oxides is commonly implicated as the primary culprit. Confounding our understanding of processes controlling As retention, however, is that reductive transformation of ferrihydrite has recently been shown to promote As retention rather than release. To resolve the role iron phases have in regulating arsenic concentrations, here we examine As desorption from ferrihydrite-coated sands presorbed with As(lll); experiments were performed at circumneutral pH under Fe-reducing conditions with the dissimilatory iron reducing bacterium Shewanella putrefaciens strain CN-32 over extended time periods. We reveal that with the initial phase of iron reduction, ferrihydrite undergoes transformation to secondary phases and increases As(lll) retention (relative to abiotic controls). However, with increased reaction time, cessation of the phase transitions and ensuing reductive dissolution result in prolonged release of As(III) to the aqueous phase. Our results suggest that As(lll) retention during iron reduction is temporally dependent on secondary precipitation of iron phases; during transformation to secondary phases, particularly magnetite, As(lll) retention is enhanced even relative to oxidized systems. However, conditions that retard secondary transformation (more stable iron oxides or limited iron reducing bacterial activity), or prolonged anaerobiosis, will lead to both the dissolution of ferric (hydr)oxides and release of As(lll) to the aqueous phase.

  7. Smoking and Hormesis as Confounding Factors in Radiation Pulmonary Carcinogenesis

    PubMed Central

    Sanders, Charles L.; Scott, Bobby R.

    2008-01-01

    Confounding factors in radiation pulmonary carcinogenesis are passive and active cigarette smoke exposures and radiation hormesis. Significantly increased lung cancer risk from ionizing radiation at lung doses < 1 Gy is not observed in never smokers exposed to ionizing radiations. Residential radon is not a cause of lung cancer in never smokers and may protect against lung cancer in smokers. The risk of lung cancer found in many epi-demiological studies was less than the expected risk (hormetic effect) for nuclear weapons and power plant workers, shipyard workers, fluoroscopy patients, and inhabitants of high-dose background radiation. The protective effect was noted for low- and mixed high- and low-linear energy transfer (LET) radiations in both genders. Many studies showed a protection factor (PROFAC) > 0.40 (40% avoided) against the occurrence of lung cancer. The ubiquitous nature of the radiation hormesis response in cellular, animal, and epidemio-logical studies negates the healthy worker effect as an explanation for radiation hormesis. Low-dose radiation may stimulate DNA repair/apoptosis and immunity to suppress and eliminate cigarette-smoke-induced transformed cells in the lung, reducing lung cancer occurrence in smokers. PMID:18648572

  8. Adhesion: a confounding bias in murine cervical heterotopic heart transplantation

    PubMed Central

    Yang, Jinghui; Chen, Qi; Liu, Fang; Fu, Zhiren; Wang, Quanxing

    2015-01-01

    Tissue adhesion is a common postsurgical phenomenon among the human population. This complication also occurs in murine transplant models. In this study, we investigated the impact of adhesion on murine cervical heterotopic heart transplantation by using sodium hyaluronate (SH) as an anti-adhesive agent. Our study revealed that SH administration produced no significant effect on histological change, TNF-α, IFN-γ, MCP-1, IL-2, IL-6 and IL-10 expression, CD4+ T, CD8+ T, or neutrophil and macrophage counts. Our findings suggest that SH was biocompatible and non-immunogenic. Later, we observed that adhesion not only affected the survival of the graft without mediating rejection, but was closely related to the severity of rejection as manifested by larger and more severe adhesion formation in total-allomismatched and MHC class II-allomismatched murine cardiac allografts. Therefore, we inferred that using the murine cervical heterotopic heart transplant model may lead to an exaggerated p-value in statistical significance testing which could mislead experimenters in considering that the results are more significant than the fact. To the best of our knowledge, this study is the first demonstration that proves that adhesion was a confounding bias in the murine cervical heterotopic heart transplant model and highlights the possibilities for improvement in future use. PMID:26550450

  9. Prostate-Specific Antigen Velocity Before and After Elimination of Factors That Can Confound the Prostate-Specific Antigen Level

    SciTech Connect

    Park, Jessica J.; Chen, Ming-Hui; Loffredo, Marian; D'Amico, Anthony V.

    2012-03-01

    Purpose: Prostate-specific antigen (PSA) velocity, like PSA level, can be confounded. In this study, we estimated the impact that confounding factors could have on correctly identifying a patient with a PSA velocity >2 ng/ml/y. Methods and Materials: Between 2006 and 2010, a total of 50 men with newly diagnosed PC comprised the study cohort. We calculated and compared the false-positive and false-negative PSA velocity >2 ng/ml/y rates for all men and those with low-risk disease using two approaches to calculate PSA velocity. First, we used PSA values obtained within 18 months of diagnosis; second, we used values within 18 months of diagnosis, substituting the prebiopsy PSA for a repeat, nonconfounded PSA that was obtained using the same assay and without confounders. Results: Using PSA levels pre-biopsy, 46% of all men had a PSA velocity >2 ng/ml/y; whereas this value declined to 32% when substituting the last prebiopsy PSA for a repeat, nonconfounded PSA using the same assay and without confounders. The false-positive rate for PSA velocity >2 ng/ml/y was 43% as compared with a false-negative rate of PSA velocity >2 ng/ml/y of 11% (p = 0.0008) in the overall cohort. These respective values in the low-risk subgroup were 60% and 16.7% (p = 0.09). Conclusion: This study provides evidence to explain the discordance in cancer-specific outcomes among groups investigating the prognostic significance of PSA velocity >2 ng/ml/y, and highlights the importance of patient education on potential confounders of the PSA test before obtaining PSA levels.

  10. Ultrasound Elastography and MR Elastography for Assessing Liver Fibrosis: Part 2, Diagnostic Performance, Confounders, and Future Directions

    PubMed Central

    Tang, An; Cloutier, Guy; Szeverenyi, Nikolaus M.; Sirlin, Claude B.

    2016-01-01

    OBJECTIVE The purpose of the article is to review the diagnostic performance of ultrasound and MR elastography techniques for detection and staging of liver fibrosis, the main current clinical applications of elastography in the abdomen. CONCLUSION Technical and instrument-related factors and biologic and patient-related factors may constitute potential confounders of stiffness measurements for assessment of liver fibrosis. Future developments may expand the scope of elastography for monitoring liver fibrosis and predict complications of chronic liver disease. PMID:25905762

  11. Calculations of the ionization potentials of the halogens by the relativistic Hartree-Rock-Dirac method taking account of superposition of configurations

    SciTech Connect

    Tupitsyn, I.I.

    1988-03-01

    The ionization potentials of the halogen group have been calculated. The calculations were carried out using the relativistic Hartree-Fock method taking into account correlation effects. Comparison of theoretical results with experimental data for the elements F, Cl, Br, and I allows an estimation of the accuracy and reliability of the method. The theoretical values of the ionization potential of astatine obtained here may be of definite interest for the chemistry of astatine.

  12. Confounding variables in the environmental toxicology of arsenic.

    PubMed

    Gebel, T

    2000-04-01

    Arsenic is one of the most important global environmental toxicants. For example, in regions of West Bengal and Inner Mongolia, more than 100000 persons are chronically exposed to well water often strongly contaminated with As. Unfortunately, a toxicologically safe risk assessment and standard setting, especially for long-term and low-dose exposures to arsenic, is not possible. One reason is that the key mechanism of arsenic's tumorigenicity still is not elucidated. Experimental data indicate that either DNA repair inhibition or DNA methylation status alteration may be causal explanations. Moreover, when comparing epidemiological data, it cannot be ruled out that the susceptibility to arsenic's carcinogenicity may be different between Mexican and Taiwanese people. Some other studies indicate that some Andean populations do not develop skin cancer after long-term exposure to As. It is not known yet how this resistance could be mediated. Finally, the situation is even more complicated when taking into consideration that there are several compounds suspected to modulate the chronic environmental toxicity of arsenic, variables that may either enhance or suppress the in vivo genotoxicity and carcinogenicity of the metalloid. Among them are nutritional factors like selenium and zinc as well as drinking water co-contaminants like antimony. Further, yet unidentified factors influencing the body burden and/or the excretion of arsenic are possibly prevailing: preliminary data from own human biomonitoring studies showed a peaking of As in urine samples of non-exposed people which was not caused by elevated exposure to As through seafood consumption. The relevance of these putative confounding variables cannot be finally evaluated yet. Further experimental as well as epidemiological studies are needed to answer these questions. This would help to conduct a toxicologically improved risk assessment, especially for low-dose and long-term exposures to arsenic.

  13. Measuring rDNA diversity in eukaryotic microbial systems: how intragenomic variation, pseudogenes, and PCR artifacts confound biodiversity estimates.

    PubMed

    Thornhill, Daniel J; Lajeunesse, Todd C; Santos, Scott R

    2007-12-01

    Molecular approaches have revolutionized our ability to study the ecology and evolution of micro-organisms. Among the most widely used genetic markers for these studies are genes and spacers of the rDNA operon. However, the presence of intragenomic rDNA variation, especially among eukaryotes, can potentially confound estimates of microbial diversity. To test this hypothesis, bacterially cloned PCR products of the internal transcribed spacer (ITS) region from clonal isolates of Symbiodinium, a large genus of dinoflagellates that live in symbiosis with many marine protists and invertebrate metazoa, were sequenced and analysed. We found widely differing levels of intragenomic sequence variation and divergence in representatives of Symbiodinium clades A to E, with only a small number of variants attributed to Taq polymerase/bacterial cloning error or PCR chimeras. Analyses of 5.8S-rDNA and ITS2 secondary structure revealed that some variants possessed base substitutions and/or indels that destabilized the folded form of these molecules; given the vital nature of secondary structure to the function of these molecules, these likely represent pseudogenes. When similar controls were applied to bacterially cloned ITS sequences from a recent survey of Symbiodinium diversity in Hawaiian Porites spp., most variants (approximately 87.5%) possessed unstable secondary structures, had unprecedented mutations, and/or were PCR chimeras. Thus, data obtained from sequencing of bacterially cloned rDNA genes can substantially exaggerate the level of eukaryotic microbial diversity inferred from natural samples if appropriate controls are not applied. These considerations must be taken into account when interpreting sequence data generated by bacterial cloning of multicopy genes such as rDNA.

  14. Parasitism can be a confounding factor in assessing the response of zebra mussels to water contamination.

    PubMed

    Minguez, Laëtitia; Buronfosse, Thierry; Beisel, Jean-Nicolas; Giambérini, Laure

    2012-03-01

    Biological responses measured in aquatic organisms to monitor environmental pollution could be also affected by different biotic and abiotic factors. Among these environmental factors, parasitism has often been neglected even if infection by parasites is very frequent. In the present field investigation, the parasite infra-communities and zebra mussel biological responses were studied up- and downstream a waste water treatment plant in northeast France. In both sites, mussels were infected by ciliates and/or intracellular bacteria, but prevalence rates and infection intensities were different according to the habitat. Concerning the biological responses differences were observed related to the site quality and the infection status. Parasitism affects both systems but seemed to depend mainly on environmental conditions. The influence of parasites is not constant, but remains important to consider it as a potential confounding factor in ecotoxicological studies. This study also emphasizes the interesting use of integrative indexes to synthesize data set. PMID:22243869

  15. Duration perception of emotional stimuli: Using evaluative conditioning to avoid sensory confounds.

    PubMed

    Kliegl, Katrin M; Watrin, Luc; Huckauf, Anke

    2015-01-01

    It has been found that emotional pictures are estimated to last longer than neutral ones. However, emotional and neutral stimuli often differ in their physical characteristics, too. Since this might also affect time perception, we present a method disentangling a possible confounding regarding the processing of physically different stimulus material. In the evaluative condition paradigm, participants, at first, learnt the association of neutral images with a certain Landolt ring and of emotional images with another Landolt ring with a different gap position. The conditioned Landolt rings were subsequently used in a temporal bisection task. In two experiments, the results revealed a temporal overestimation of Landolt rings conditioned with emotional pictures compared to neutral pictures showing that the temporal overestimation of emotional stimuli cannot be attributed to perceptual differences between neutral and emotional stimuli. The method provides the potential for investigating emotional effects on various perceptual processes.

  16. Parasitism can be a confounding factor in assessing the response of zebra mussels to water contamination.

    PubMed

    Minguez, Laëtitia; Buronfosse, Thierry; Beisel, Jean-Nicolas; Giambérini, Laure

    2012-03-01

    Biological responses measured in aquatic organisms to monitor environmental pollution could be also affected by different biotic and abiotic factors. Among these environmental factors, parasitism has often been neglected even if infection by parasites is very frequent. In the present field investigation, the parasite infra-communities and zebra mussel biological responses were studied up- and downstream a waste water treatment plant in northeast France. In both sites, mussels were infected by ciliates and/or intracellular bacteria, but prevalence rates and infection intensities were different according to the habitat. Concerning the biological responses differences were observed related to the site quality and the infection status. Parasitism affects both systems but seemed to depend mainly on environmental conditions. The influence of parasites is not constant, but remains important to consider it as a potential confounding factor in ecotoxicological studies. This study also emphasizes the interesting use of integrative indexes to synthesize data set.

  17. Polymorphisms in DNA-Repair Genes in a Cohort of Prostate Cancer Patients from Different Areas in Spain: Heterogeneity between Populations as a Confounding Factor in Association Studies

    PubMed Central

    Henríquez-Hernández, Luis Alberto; Valenciano, Almudena; Foro-Arnalot, Palmira; Álvarez-Cubero, María Jesús; Cozar, José Manuel; Suárez-Novo, José Francisco; Castells-Esteve, Manel; Ayala-Gil, Adriana; Fernández-Gonzalo, Pablo; Ferrer, Montse; Guedea, Ferrán; Sancho-Pardo, Gemma; Craven-Bartle, Jordi; Ortiz-Gordillo, María José; Cabrera-Roldán, Patricia; Herrera-Ramos, Estefanía; Lara, Pedro C.

    2013-01-01

    Background Differences in the distribution of genotypes between individuals of the same ethnicity are an important confounder factor commonly undervalued in typical association studies conducted in radiogenomics. Objective To evaluate the genotypic distribution of SNPs in a wide set of Spanish prostate cancer patients for determine the homogeneity of the population and to disclose potential bias. Design, Setting, and Participants A total of 601 prostate cancer patients from Andalusia, Basque Country, Canary and Catalonia were genotyped for 10 SNPs located in 6 different genes associated to DNA repair: XRCC1 (rs25487, rs25489, rs1799782), ERCC2 (rs13181), ERCC1 (rs11615), LIG4 (rs1805388, rs1805386), ATM (rs17503908, rs1800057) and P53 (rs1042522). The SNP genotyping was made in a Biotrove OpenArray® NT Cycler. Outcome Measurements and Statistical Analysis Comparisons of genotypic and allelic frequencies among populations, as well as haplotype analyses were determined using the web-based environment SNPator. Principal component analysis was made using the SnpMatrix and XSnpMatrix classes and methods implemented as an R package. Non-supervised hierarchical cluster of SNP was made using MultiExperiment Viewer. Results and Limitations We observed that genotype distribution of 4 out 10 SNPs was statistically different among the studied populations, showing the greatest differences between Andalusia and Catalonia. These observations were confirmed in cluster analysis, principal component analysis and in the differential distribution of haplotypes among the populations. Because tumor characteristics have not been taken into account, it is possible that some polymorphisms may influence tumor characteristics in the same way that it may pose a risk factor for other disease characteristics. Conclusion Differences in distribution of genotypes within different populations of the same ethnicity could be an important confounding factor responsible for the lack of validation of

  18. Do pollution time-series studies contain uncontrolled or residual confounding by risk factors for acute health events?

    PubMed

    Bukowski, John

    2008-07-01

    Acute health effects from air pollution are based largely on weak associations identified in time-series studies comparing daily air pollution levels to daily mortality. Much of this mortality is due to cardiovascular disease. Time-series studies have many potential limitations, but are not thought to be confounded by traditional cardiovascular risk factors (e.g., smoking status or hypertension) because these chronic risk factors are not obviously associated with daily pollution levels. However, acute psychobehavioral variants of these risk factors (e.g., smoking patterns and episodes of stress on any given day) are plausible confounders for the associations observed in time-series studies, given that time-series studies attempt to predict acute rather than chronic health outcomes. There is a fairly compelling literature on the strong link between cardiovascular events and daily "triggers" such as stress. Stress-related triggers are plausibly associated with daily pollution levels through surrogate stressors such as ambient temperature, daily workload, local traffic congestion, or other correlates of air pollution. For example, variables such as traffic congestion and industrial activity increase both stress-related health events and air pollution, suggesting the potential for classical confounding. Support for this argument is illustrated through examples of the well-demonstrated relationship between emotional stress and heart attack/stroke.

  19. Sediment organic matter content as a confounding factor in toxicity tests with Chironomus tentans

    SciTech Connect

    Lacey, R.; Watzin, M.C.; McIntosh, A.W.

    1999-02-01

    Physicochemical characteristics of sediment unrelated to contaminant levels and bioavailability may influence the outcome of toxicity tests. In particular, sediment organic matter content has the potential to be a confounding factor in toxicity tests using the midge larva Chironomus tentans because the larvae are infaunal and feed on organic matter in the sediments. To examine the possibility, the authors conducted a series of tests using formulated sediments with varying organic matter contents following the standard US Environmental Protection Agency (US EPA) 10-day C. tentans growth and survival protocol. Formulated sediments made with peat moss, {alpha}-cellulose, and maple leaves were tested. An organic-rich natural sediment diluted with formulated sediment to achieve a range of organic matter contents was also examined. In a final experiment, sediments containing each of the four organic matter sources at the same concentration were tested against one another. Survival was not greatly affected by concentration of organic matter, except at the lowest concentrations in natural sediment, where survival dipped below 70%. In experiments using peat moss, {alpha}-cellulose, and maple leaves, significant differences in C. tentans growth were found at different organic matter concentrations. In contrast, concentration of organic matter in the natural sediment dilution series had little effect on growth, perhaps because much of this material was highly refractory. In the comparison experiment, growth differed significantly among the four sediments, with best growth achieved with {alpha}-cellulose and leaves. These results suggest that both organic matter quantity and quality can be confounding factors in toxicity tests using C. tentans.

  20. On calculation of the electrostatic potential of a phosphatidylinositol phosphate-containing phosphatidylcholine lipid membrane accounting for membrane dynamics.

    PubMed

    Fuller, Jonathan C; Martinez, Michael; Wade, Rebecca C

    2014-01-01

    Many signaling events require the binding of cytoplasmic proteins to cell membranes by recognition of specific charged lipids, such as phosphoinositol-phosphates. As a model for a protein-membrane binding site, we consider one charged phosphoinositol phosphate (PtdIns(3)P) embedded in a phosphatidylcholine bilayer. As the protein-membrane binding is driven by electrostatic interactions, continuum solvent models require an accurate representation of the electrostatic potential of the phosphoinositol phosphate-containing membrane. We computed and analyzed the electrostatic potentials of snapshots taken at regular intervals from molecular dynamics simulations of the bilayer. We observe considerable variation in the electrostatic potential of the bilayer both along a single simulation and between simulations performed with the GAFF or CHARMM c36 force fields. However, we find that the choice of GAFF or CHARMM c36 parameters has little effect on the electrostatic potential of a given configuration of the bilayer with a PtdIns(3)P embedded in it. From our results, we propose a remedian averaging method for calculating the electrostatic potential of a membrane system that is suitable for simulations of protein-membrane binding with a continuum solvent model.

  1. Structural confounding of area-level deprivation and segreation: an empirical example

    EPA Science Inventory

    The neighborhood effects literature has grown, but its utility is limited by the lack of attention paid to non-random selection into neighborhoods. Confounding occurs when an exposure and an outcome share an underlying common cause. Confounding resulting from differential allocat...

  2. Bed Sharing, SIDS Research, and the Concept of Confounding: A Review for Public Health Nurses.

    PubMed

    Keys, Elizabeth M; Rankin, James A

    2015-01-01

    Confounding is an important concept for public health nurses (PHNs) to understand when considering the results of epidemiological research. The term confounding is derived from Latin, confundere, which means to "mix-up" or "mix together". Epidemiologists attempt to derive a cause and effect relationship between two variables traditionally known as the exposure and disease (e.g., smoking and lung cancer). Confounding occurs when a third factor, known as a confounder, leads to an over- or underestimate of the magnitude of the association between the exposure and disease. An understanding of confounding will facilitate critical appraisal of epidemiological research findings. This knowledge will enable PHNs to strengthen their evidence-based practice and better prepare them for policy development and implementation. In recent years, researchers and clinicians have examined the relationship between bed sharing and sudden infant death syndrome (SIDS). The discussion regarding the risk of bed sharing and SIDS provides ample opportunity to discuss the various aspects of confounding. The purpose of this article is to use the bed sharing and SIDS literature to assist PHNs to understand confounding and to apply this knowledge when appraising epidemiological research. In addition, strategies that are used to control confounding are discussed.

  3. A Harmonious Accounting Duo?

    ERIC Educational Resources Information Center

    Schapperle, Robert F.; Hardiman, Patrick F.

    1992-01-01

    Accountants have urged "harmonization" of standards between the Governmental Accounting Standards Board and the Financial Accounting Standards Board, recommending similar reporting of like transactions. However, varying display of similar accounting events does not necessarily indicate disharmony. The potential for problems because of differing…

  4. Diminished KCC2 confounds synapse specificity of LTP during senescence.

    PubMed

    Ferando, Isabella; Faas, Guido C; Mody, Istvan

    2016-09-01

    The synapse specificity of long-term potentiation (LTP) ensures that no interference arises from inputs irrelevant to the memory to be encoded. In hippocampi of aged (21-28 months) mice, LTP was relayed to unstimulated synapses, blemishing its synapse specificity. Diminished levels of the K(+)/Cl(-) cotransporter KCC2 and a depolarizing GABAA receptor-mediated synaptic component following LTP were the most likely causes for the spreading of potentiation, unveiling mechanisms hindering information storage in the aged brain and identifying KCC2 as a potential target for intervention. PMID:27500406

  5. Is it patience or motivation? On motivational confounds in intertemporal choice tasks.

    PubMed

    Paglieri, Fabio; Addessi, Elsa; Sbaffi, Agnese; Tasselli, Maria Isabella; Delfino, Alexia

    2015-01-01

    Intertemporal choices create a tension between amount maximization, which would favor the larger and later option (LL), and delay minimization, which would promote the smaller and sooner reward (SS). Two common interpretations of intertemporal choice behavior are discussed: looking at LL responses as indicative of self-control, and using intertemporal choices to assess delay aversion. We argue that both interpretations need to take into account motivational confounds, in order to be warranted by data. In intertemporal choices with prepotent, salient stimuli (e.g., food amounts, typically used with nonhuman primates), LL responses could also be indicative of failed inhibition of a "go for more" impulsive response-the opposite of self-control. Similarly, intertemporal choices can be used to measure delay aversion only with respect to the subject's baseline motivation to maximize the reinforcer in question, and this baseline is not always assessed in current experimental protocols. This concern is especially crucial in comparing intertemporal choices across different groups or manipulation. We focus in particular on the effects of reward types on intertemporal choices, presenting two experimental studies where the difference in behavior with monetary versus food rewards is the product of different baseline motivation, rather than variations in delay aversion. We conclude discussing the implications of these and other similar recent findings, which are far-reaching. PMID:25545635

  6. A causal examination of the effects of confounding factors on multimetric indices

    USGS Publications Warehouse

    Schoolmaster, Donald R.; Grace, James B.; Schweiger, E. William; Mitchell, Brian R.; Guntenspergen, Glenn R.

    2013-01-01

    The development of multimetric indices (MMIs) as a means of providing integrative measures of ecosystem condition is becoming widespread. An increasingly recognized problem for the interpretability of MMIs is controlling for the potentially confounding influences of environmental covariates. Most common approaches to handling covariates are based on simple notions of statistical control, leaving the causal implications of covariates and their adjustment unstated. In this paper, we use graphical models to examine some of the potential impacts of environmental covariates on the observed signals between human disturbance and potential response metrics. Using simulations based on various causal networks, we show how environmental covariates can both obscure and exaggerate the effects of human disturbance on individual metrics. We then examine from a causal interpretation standpoint the common practice of adjusting ecological metrics for environmental influences using only the set of sites deemed to be in reference condition. We present and examine the performance of an alternative approach to metric adjustment that uses the whole set of sites and models both environmental and human disturbance effects simultaneously. The findings from our analyses indicate that failing to model and adjust metrics can result in a systematic bias towards those metrics in which environmental covariates function to artificially strengthen the metric–disturbance relationship resulting in MMIs that do not accurately measure impacts of human disturbance. We also find that a “whole-set modeling approach” requires fewer assumptions and is more efficient with the given information than the more commonly applied “reference-set” approach.

  7. Choroidal abnormalities and masquerade syndromes confounding the diagnosis of laser-induced eye injuries

    NASA Astrophysics Data System (ADS)

    Hacker, Henry D.; Zwick, Harry; Brown, Jeremiah, Jr.; Dicks, Ronald; Cheramie, Rachel; Stuck, Bruce E.

    2005-04-01

    The diagnosis of a laser-induced eye injury occurring in occupational or military environments is often complicated by confounding symptoms, the possibility of pre-existing pathology, and/or a lack of visual deficits that can be clearly associated with a specific incident. Two recent cases are described that illustrate the importance of a thorough differential diagnosis when coexisting retinal pathologies are present with potentially different (e.g. laser or disease) etiologies. Indocyanine green angiography (ICG) and ocular coherence tomography (OCT) used in combination with standard ophthalmic imaging can provide helpful insights as to the etiology of these lesions. Vascular choroidal abnormalities such as hemangiomas or occult histoplasmosis infection can produce findings that can mimic the leakage that may be evident from neovascular membranes associated with laser injury. Further evaluation with OCT and conventional fluorescein angiography (FA) is helpful to look for the classic signature of retinal disruption and retinal pigment layer changes that are often present in association with laser injury. Furthermore, a careful situational assessment of a potential laser exposure is important to confirm the diagnosis of laser-induced eye injury.

  8. Measuring oxidative stress: the confounding effect of lipid concentration in measures of lipid peroxidation.

    PubMed

    Pérez-Rodríguez, Lorenzo; Romero-Haro, Ana A; Sternalski, Audrey; Muriel, Jaime; Mougeot, Francois; Gil, Diego; Alonso-Alvarez, Carlos

    2015-01-01

    Lipid peroxidation products are widely used as markers of oxidative damage in the organism. To properly interpret the information provided by these markers, it is necessary to know potential sources of bias and control confounding factors. Here, we investigated the relationship between two indicators of lipid mobilization (circulating levels of triglycerides and cholesterol) and two common markers of oxidative damage (plasma levels of malondialdehyde and hydroperoxides; the latter estimated from the d-ROMs assay kit). The following five avian species were studied: red-legged partridge (Alectoris rufa), zebra finch (Taeniopygia guttata), spotless starling (Sturnus unicolor), marsh harrier (Circus aeroginosus), and Montagu's harrier (Circus pygargus). In all cases, plasma triglyceride levels positively and significantly correlated with lipid peroxidation markers, explaining between 8% and 34% of their variability. Plasma cholesterol, in contrast, showed a significant positive relationship only among spotless starling nestlings and a marginally significant association in zebra finches. These results indicate that lipid peroxidation marker levels covary with circulating lipid levels. We discuss the potential causes and implications of this covariation and recommend that future studies that measure oxidative damage using lipid peroxidation markers report both raw and relative levels (i.e., corrected for circulating triglycerides). Whether the observed pattern also holds for other tissues and in other taxa would deserve further research.

  9. Confounding effects of phase delays on causality estimation.

    PubMed

    Vakorin, Vasily A; Mišić, Bratislav; Krakovska, Olga; Bezgin, Gleb; McIntosh, Anthony R

    2013-01-01

    Linear and non-linear techniques for inferring causal relations between the brain signals representing the underlying neuronal systems have become a powerful tool to extract the connectivity patterns in the brain. Typically these tools employ the idea of Granger causality, which is ultimately based on the temporal precedence between the signals. At the same time, phase synchronization between coupled neural ensembles is considered a mechanism implemented in the brain to integrate relevant neuronal ensembles to perform a cognitive or perceptual task. Phase synchronization can be studied by analyzing the effects of phase-locking between the brain signals. However, we should expect that there is no one-to-one mapping between the observed phase lag and the time precedence as specified by physically interacting systems. Specifically, phase lag observed between two signals may interfere with inferring causal relations. This could be of critical importance for the coupled non-linear oscillating systems, with possible time delays in coupling, when classical linear cross-spectrum strategies for solving phase ambiguity are not efficient. To demonstrate this, we used a prototypical model of coupled non-linear systems, and compared three typical pipelines of inferring Granger causality, as established in the literature. Specifically, we compared the performance of the spectral and information-theoretic Granger pipelines as well as standard Granger causality in their relations to the observed phase differences for frequencies at which the signals become synchronized to each other. We found that an information-theoretic approach, which takes into account different time lags between the past of one signal and the future of another signal, was the most robust to phase effects.

  10. Chloroform-induced insanity defence confounds lawyer Lincoln.

    PubMed

    Spiegel, A D; Suskind, P B

    1997-12-01

    During an 1857 trial, the defence claimed that the accused should be absolved of wilful murder because an overdose of chloroform during surgery induced insanity. In a rare appearance as a prosecutor, Abraham Lincoln tried the case for the State of Illinois. Expert medical witnesses testified about the side effects of chloroform and chloroform-induced insanity. Significantly, Lincoln was not knowledgeable about medical jurisprudence and overlooked potential sources of evidence and expert witnesses. Defence lawyers presented an impressive array of physicians to testify about insanity, about chloroform and about the results of an overdosage during anaesthesia. Considering the state of scientific knowledge at the time, the trial was notable.

  11. Vitamin D in Fibromyalgia: A Causative or Confounding Biological Interplay?

    PubMed Central

    Karras, Spyridon; Rapti, Eleni; Matsoukas, Stauros; Kotsa, Kalliopi

    2016-01-01

    Fibromyalgia (FM) is a chronic syndrome with an increasing prevalence, characterized by widespread musculoskeletal pain in combination with a variety of cognitive symptoms and fatigue. A plethora of scientific evidence that has accumulated during the last decades, resulted in a significant improvement of the understanding of the pathophysiology of the disease. However, current therapeutic approaches in patients with FM remains a multidimensional approach including patient education, behavioral therapy, exercise, pain management, and relief of chronic symptoms, rather than the use drug therapies, based on the mechanisms of disease development. Vitamin D, a fat-soluble vitamin derived mainly from skin synthesis through ultraviolet radiation, has been recognized to manifest a plethora of extraskeletal actions, apart from its fundamental role in skeletal and calcium homeostasis, including modulation of cell growth, neuromuscular actions, and potential anti-inflammatory properties. Recent findings indicate that hypovitaminosis D to be highly prevalent in patients with FM. Supplementation studies are limited so far, indicating potential beneficial effects on pain and severity of the disease, however specific recommendations are lacking. This review aims to summarize and critically appraise data regarding the pathophysiological interplay between vitamin D and FM, available results from observational and supplementation studies so far, with a clinical discourse on current knowledge gaps and future research agenda. PMID:27271665

  12. Evening Activities as a Potential Confound in Research on the Adrenocortical System in Children

    ERIC Educational Resources Information Center

    Kertes, Darlene A.; Gunnar, Megan R.

    2004-01-01

    The relation among children's evening activities, behavioral characteristics, and activity of the hypothalamic-pituitary-adrenocortical axis was assessed in normally developing children ages 7 to 10 years. Salivary cortisol at bedtime was compared on evenings when children had structured activities outside of the home with unstructured evenings at…

  13. Gender Bias in the Diagnosis of a Geriatric Standardized Patient: A Potential Confounding Variable

    ERIC Educational Resources Information Center

    Lewis, Roya; Lamdan, Ruth M.; Wald, David; Curtis, Michael

    2006-01-01

    Background: Gender bias has been reported in the diagnosis and treatment of patients with a variety of illnesses. In the context of our 10-station fourth year Objective Structured Clinical Evaluation, we queried whether this could influence diagnosis in a geriatric case. Case writers hypothesized that, due to this bias, the female standardized…

  14. LIFE CLIMATREE project: A novel approach for accounting and monitoring carbon sequestration of tree crops and their potential as carbon sink areas

    NASA Astrophysics Data System (ADS)

    Stergiou, John; Tagaris, Efthimios; -Eleni Sotiropoulou, Rafaella

    2016-04-01

    Climate Change Mitigation is one of the most important objectives of the Kyoto Convention, and is mostly oriented towards reducing GHG emissions. However, carbon sink is retained only in the calculation of the forests capacity since agricultural land and farmers practices for securing carbon stored in soils have not been recognized in GHG accounting, possibly resulting in incorrect estimations of the carbon dioxide balance in the atmosphere. The agricultural sector, which is a key sector in the EU, presents a consistent strategic framework since 1954, in the form of Common Agricultural Policy (CAP). In its latest reform of 2013 (reg. (EU) 1305/13) CAP recognized the significance of Agriculture as a key player in Climate Change policy. In order to fill this gap the "LIFE ClimaTree" project has recently founded by the European Commission aiming to provide a novel method for including tree crop cultivations in the LULUCF's accounting rules for GHG emissions and removal. In the framework of "LIFE ClimaTree" project estimation of carbon sink within EU through the inclusion of the calculated tree crop capacity will be assessed for both current and future climatic conditions by 2050s using the GISS-WRF modeling system in a very fine scale (i.e., 9km x 9km) using RCP8.5 and RCP4.5 climate scenarios. Acknowledgement: LIFE CLIMATREE project "A novel approach for accounting and monitoring carbon sequestration of tree crops and their potential as carbon sink areas" (LIFE14 CCM/GR/000635).

  15. Breast milk and cognitive development—the role of confounders: a systematic review

    PubMed Central

    Walfisch, Asnat; Sermer, Corey; Cressman, Alex; Koren, Gideon

    2013-01-01

    Objectives The association between breastfeeding and child cognitive development is conflicted by studies reporting positive and null effects. This relationship may be confounded by factors associated with breastfeeding, specifically maternal socioeconomic class and IQ. Design Systematic review of the literature. Setting and participants Any prospective or retrospective study, in any language, evaluating the association between breastfeeding and cognitive development using a validated method in healthy term infants, children or adults, was included. Primary and secondary outcome measures Extracted data included the study design, target population and sample size, breastfeeding exposure, cognitive development assessment tool used and participants’ age, summary of the results prior to, and following, adjustment for confounders, and all confounders adjusted for. Study quality was assessed as well. Results 84 studies met our inclusion criteria (34 rated as high quality, 26 moderate and 24 low quality). Critical assessment of accepted studies revealed the following associations: 21 null, 28 positive, 18 null after adjusting for confounders and 17 positive—diminished after adjusting for confounders. Directionality of effect did not correlate with study quality; however, studies showing a decreased effect after multivariate analysis were of superior quality compared with other study groupings (14/17 high quality, 82%). Further, studies that showed null or diminished effect after multivariate analysis corrected for significantly more confounders (7.7±3.4) as compared with those that found no change following adjustment (5.6±4.5, p=0.04). The majority of included studies were carried out during childhood (75%) and set in high-income countries (85.5%). Conclusions Much of the reported effect of breastfeeding on child neurodevelopment is due to confounding. It is unlikely that additional work will change the current synthesis. Future studies should attempt to rigorously

  16. Confounders in interpreting pathology for safety and risk assessment

    SciTech Connect

    Wolf, Douglas C. . E-mail: wolf.doug@epa.gov; Mann, Peter C.

    2005-02-01

    The contribution of pathology to toxicity assessment is invaluable but often not clearly understood. Pathology endpoints are the central response around which human health risk assessment is frequently determined; therefore, it is important that the general toxicology community understand current concepts and nomenclature of toxicologic pathology. Toxicologic pathology encompasses the study of changes in tissue morphology that help define the risk of exposure to xenobiotics. Toxicologic pathology is a discipline that has changed and adapted over time including methods of analysis and nomenclature of lesions. As risk assessments are updated for chemicals in commerce, frequently the older literature must be reviewed and reevaluated. When interpreting pathology data from animal studies, it is important to consider the biological significance of a lesion as well as its relationship to the ultimate adverse health effect. Assessing the potential for a chemical to cause harm to humans must include the examination of the entire pathology database in context of the study design, the mode of action of the chemical of concern, and using the most current interpretation of a lesion to determine the significance for human health effects of a particular tissue response.

  17. Statistically Controlling for Confounding Constructs Is Harder than You Think

    PubMed Central

    Westfall, Jacob; Yarkoni, Tal

    2016-01-01

    Social scientists often seek to demonstrate that a construct has incremental validity over and above other related constructs. However, these claims are typically supported by measurement-level models that fail to consider the effects of measurement (un)reliability. We use intuitive examples, Monte Carlo simulations, and a novel analytical framework to demonstrate that common strategies for establishing incremental construct validity using multiple regression analysis exhibit extremely high Type I error rates under parameter regimes common in many psychological domains. Counterintuitively, we find that error rates are highest—in some cases approaching 100%—when sample sizes are large and reliability is moderate. Our findings suggest that a potentially large proportion of incremental validity claims made in the literature are spurious. We present a web application (http://jakewestfall.org/ivy/) that readers can use to explore the statistical properties of these and other incremental validity arguments. We conclude by reviewing SEM-based statistical approaches that appropriately control the Type I error rate when attempting to establish incremental validity. PMID:27031707

  18. From bad to worse: collider stratification amplifies confounding bias in the "obesity paradox".

    PubMed

    Banack, Hailey R; Kaufman, Jay S

    2015-10-01

    Smoking is often identified as a confounder of the obesity-mortality relationship. Selection bias can amplify the magnitude of an existing confounding bias. The objective of the present report is to demonstrate how confounding bias due to cigarette smoking is increased in the presence of collider stratification bias using an empirical example and directed acyclic graphs. The empirical example uses data from the Atherosclerosis Risk in Communities (ARIC) study, a prospective cohort study of 15,792 men and women in the United States. Poisson regression models were used to examine the confounding effect of smoking. In the total ARIC study population, smoking produced a confounding bias of <3 percentage points. This result was obtained by comparing the incidence rate ratio (IRR) for obesity from a model adjusted for smoking was 1.07 (95 % CI 1.00, 1.15) with one that did not adjust for smoking was 1.10 (95 % CI 1.03, 1.18). However, among smokers with CVD, the obesity IRR was 0.89 (95 % CI 0.81, 0.99), while among non-smokers with CVD the obesity IRR was 1.20 (95 % CI 1.03, 1.41). The empirical and graphical explanations presented suggest that the magnitude of the confounding bias induced by smoking is greater in the presence of collider stratification bias.

  19. Detection rates of geckos in visual surveys: Turning confounding variables into useful knowledge

    USGS Publications Warehouse

    Lardner, Bjorn; Rodda, Gordon H.; Yackel Adams, Amy A.; Savidge, Julie A.; Reed, Robert N.

    2016-01-01

    Transect surveys without some means of estimating detection probabilities generate population size indices prone to bias because survey conditions differ in time and space. Knowing what causes such bias can help guide the collection of relevant survey covariates, correct the survey data, anticipate situations where bias might be unacceptably large, and elucidate the ecology of target species. We used negative binomial regression to evaluate confounding variables for gecko (primarily Hemidactylus frenatus and Lepidodactylus lugubris) counts on 220-m-long transects surveyed at night, primarily for snakes, on 9,475 occasions. Searchers differed in gecko detection rates by up to a factor of six. The worst and best headlamps differed by a factor of at least two. Strong winds had a negative effect potentially as large as those of searchers or headlamps. More geckos were seen during wet weather conditions, but the effect size was small. Compared with a detection nadir during waxing gibbous (nearly full) moons above the horizon, we saw 28% more geckos during waning crescent moons below the horizon. A sine function suggested that we saw 24% more geckos at the end of the wet season than at the end of the dry season. Fluctuations on a longer timescale also were verified. Disturbingly, corrected data exhibited strong short-term fluctuations that covariates apparently failed to capture. Although some biases can be addressed with measured covariates, others will be difficult to eliminate as a significant source of error in longterm monitoring programs.

  20. Wrist actigraphy for scratch detection in the presence of confounding activities.

    PubMed

    Feuerstein, Johanna; Austin, Daniel; Sack, Robert; Hayes, Tamara L

    2011-01-01

    Scratching is a symptom of many dermatological disorders, especially atopic dermatitis. For the development of anti-itch medications, there is a need for objective measures of scratching. Wrist actigraphy (monitoring wrist and hand movements with micro-accelerometers) is a promising method for assessing scratching; however, currently available technology has a limited capacity to discriminate scratching from other similar movements. In this study, we investigated methods to improve the specificity of actigraphy for scratch detection on movement data collected from subjects using the PAM-RL actigraph. A k-means cluster analysis was used to differentiate scratching from walking and restless sleep, which are potential confounds for nighttime scratching. Features used in the analysis include variance, peak frequency, autocorrelation value at one lag, and number of counts above 0.01 g's. The k-means cluster analysis exhibited a high sensitivity (0.90 ± 0.10) and specificity for walking (0.98 ± 0.05) and restless sleep (0.88 ± 0.06), respectively, demonstrating the separability of these activities. This work indicates that the features described here can be used to develop a classifier that discriminates scratch from other activities. The described method of scratch detection shows promise as an objective method for assessing scratching movements in clinical trials and longitudinal studies of scratch. PMID:22255131

  1. Assessing confounding, effect modification, and thresholds in the association between ambient particles and daily deaths.

    PubMed Central

    Schwartz, J

    2000-01-01

    I examined the relationship between daily deaths and airborne particles in 10 U.S. cities with varying climatic conditions and seasons in which particle concentrations were high. Airborne particles were associated with significant increases in daily deaths [0.67% increase for a 10 microg/m(3) increase in particles; 95% confidence interval (CI), 0.52-0.81%]. This association was the same in summer and winter. To examine potential confounding by other pollutants, I regressed city- and season-specific effect sizes against the relationship between airborne particles and other pollutants. Controlling for other pollutants did not substantially (or significantly) change the estimated effect of airborne particles. Socioeconomic differences between cities likewise did not modify the effect. The increase in daily deaths that occurred out of hospitals (0.89% per 10 microg/m(3); CI, 0.67-1.10%) was substantially greater than the increase in deaths in hospitals (0. 49%; CI, 0.31-0.68%). This is consistent with results previously reported in Philadelphia, Pennsylvania, and suggests that the particle-associated deaths are not just being brought forward by a few days. It is also consistent with recent animal and human studies of the mechanisms of particle toxicity. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 PMID:10856032

  2. Do digestive contents confound body mass as a measure of relative condition in nestling songbirds?

    USGS Publications Warehouse

    Streby, Henry M.; Peterson, Sean M.; Lehman, Justin A.; Kramer, Gunnar R.; Vernasco, Ben J.; Andersen, David E.

    2014-01-01

    Relative nestling condition, typically measured as nestling mass or as an index including nestling mass, is commonly purported to correlate with fledgling songbird survival. However, most studies directly investigating fledgling survival have found no such relationship. We weighed feces and stomach contents of nestling golden-winged warblers (Vermivora chrysoptera) to investigate the potential contribution of variation in digestive contents to differences in nestling mass. We estimated that the mass of a seventh-day (near fledging) nestling golden-winged warbler varies by 0.65 g (approx. 9% of mean nestling mass) depending on the contents of the nestling's digestive system at the time of weighing, and that digestive contents are dissimilar among nestlings at any moment the brood is removed from the nest for weighing. Our conservative estimate of within-individual variation in digestive contents equals 72% and 24% of the mean within-brood and population-wide range in nestling mass, respectively. Based on our results, a substantive but typically unknown amount of the variation in body mass among nestlings is confounded by differences in digestive contents. We conclude that short-term variation in digestive contents likely precludes the use of body mass, and therefore any mass-dependent index, as a measure of relative nestling condition or as a predictor of survival in golden-winged warblers and likely in many other songbirds of similar size.

  3. Improved estimation of controlled direct effects in the presence of unmeasured confounding of intermediate variables.

    PubMed

    Kaufman, Sol; Kaufman, Jay S; MacLehose, Richard F; Greenland, Sander; Poole, Charles

    2005-06-15

    Adjusting for a causal intermediate is a common analytic strategy for estimating an average causal direct effect (ACDE). The ACDE is the component of the total exposure effect that is not relayed through the specified intermediate. Even if the total effect is unconfounded, the usual ACDE estimate may be biased when an unmeasured variable affects the intermediate and outcome variables. Using linear programming optimization to compute non-parametric bounds, we develop new ACDE estimators for binary measured variables in this causal structure, and use root mean square confounding bias (RMSB) to compare their performance with the usual stratified estimator in simulated distributions of target populations comprised of the 64 possible potential response types as well as distributions of target populations restricted to subsets of 18 or 12 potential response types defined by monotonicity or no-interactions assumptions of unit-level causal effects. We also consider target population distributions conditioned on fixed outcome risk among the unexposed, or fixed true ACDE in one stratum of the intermediate. Results show that a midpoint estimator constructed from the optimization bounds has consistently lower RMSB than the usual stratified estimator both unconditionally and conditioned on any risk in the unexposed. When conditioning on true ACDE, this midpoint estimator performs more poorly only when conditioned on an extreme true ACDE in one stratum of the intermediate, yet outperforms the stratified estimator in the other stratum when interaction is permitted. An alternate 'limit-modified crude' estimator can never perform less favourably than the stratified estimator, and often has lower RMSB. PMID:15742358

  4. An empirical comparison of several clustered data approaches under confounding due to cluster effects in the analysis of complications of coronary angioplasty.

    PubMed

    Berlin, J A; Kimmel, S E; Ten Have, T R; Sammel, M D

    1999-06-01

    In the analysis of binary response data from many types of large studies, the data are likely to have arisen from multiple centers, resulting in a within-center correlation for the response. Such correlation, or clustering, occurs when outcomes within centers tend to be more similar to each other than to outcomes in other centers. In studies where there is also variability among centers with respect to the exposure of interest, analysis of the exposure-outcome association may be confounded, even after accounting for within-center correlations. We apply several analytic methods to compare the risk of major complications associated with two strategies, staged and combined procedures, for performing percutaneous transluminal coronary angioplasty (PTCA), a mechanical means of relieving blockage of blood vessels due to atherosclerosis. Combined procedures are used in some centers as a cost-cutting strategy. We performed a number of population-averaged and cluster-specific (conditional) analyses, which (a) make no adjustments for center effects of any kind; (b) make adjustments for the effect of center on only the response; or (c) make adjustments for both the effect of center on the response and the relationship between center and exposure. The method used for this third approach decomposes the procedure type variable into within-center and among-center components, resulting in two odds ratio estimates. The naive analysis, ignoring clusters, gave a highly significant effect of procedure type (OR = 1.6). Population average models gave marginally to very nonsignificant estimates of the OR for treatment type ranging from 1.6 to 1.2 with adjustment only for the effect of centers on response. These results depended on the assumed correlation structure. Conditional (cluster-specific) models and other methods that decomposed the treatment type variable into among- and within-center components all found no within-center effect of procedure type (OR = 1.02, consistently) and a

  5. Educational Accountability

    ERIC Educational Resources Information Center

    Pincoffs, Edmund L.

    1973-01-01

    Discusses educational accountability as the paradigm of performance contracting, presents some arguments for and against accountability, and discusses the goals of education and the responsibility of the teacher. (Author/PG)

  6. Adjusting effect estimates for unmeasured confounding with validation data using propensity score calibration

    PubMed Central

    Stürmer, Til; Schneeweiss, Sebastian; Avorn, Jerry; Glynn, Robert J

    2006-01-01

    Often important confounders are not available in studies. Sensitivity analyses based on the relation of single, but not multiple, unmeasured confounders with an exposure of interest in a separate validation study have been proposed. The authors controlled for measured confounding in the main cohort using propensity scores (PS) and addressed unmeasured confounding by estimating two additional PS in a validation study. The ‘error-prone’ PS exclusively used information available in the main cohort. The ‘gold-standard’ PS additionally included covariates available only in the validation study. Based on these two PS in the validation study, regression calibration was applied to adjust regression coefficients. This propensity score calibration (PSC) adjusts for unmeasured confounding in cohort studies with validation data under certain, usually untestable, assumptions. PSC was used to assess nonsteroidal antiinflammatory drugs (NSAID) and 1-year mortality in a large cohort of elderly. ‘Traditional’ adjustment resulted in a relative risk (RR) in NSAID users of 0.80 (95% confidence interval: 0.77–0.83) compared to an unadjusted RR of 0.68 (0.66–0.71). Application of PSC resulted in a more plausible RR of 1.06 (1.00–1.12). Until validity and limitations of PSC have been assessed in different settings, the method should be seen as a sensitivity analysis. PMID:15987725

  7. Assessment and indirect adjustment for confounding by smoking in cohort studies using relative hazards models.

    PubMed

    Richardson, David B; Laurier, Dominique; Schubauer-Berigan, Mary K; Tchetgen Tchetgen, Eric; Cole, Stephen R

    2014-11-01

    Workers' smoking histories are not measured in many occupational cohort studies. Here we discuss the use of negative control outcomes to detect and adjust for confounding in analyses that lack information on smoking. We clarify the assumptions necessary to detect confounding by smoking and the additional assumptions necessary to indirectly adjust for such bias. We illustrate these methods using data from 2 studies of radiation and lung cancer: the Colorado Plateau cohort study (1950-2005) of underground uranium miners (in which smoking was measured) and a French cohort study (1950-2004) of nuclear industry workers (in which smoking was unmeasured). A cause-specific relative hazards model is proposed for estimation of indirectly adjusted associations. Among the miners, the proposed method suggests no confounding by smoking of the association between radon and lung cancer--a conclusion supported by adjustment for measured smoking. Among the nuclear workers, the proposed method suggests substantial confounding by smoking of the association between radiation and lung cancer. Indirect adjustment for confounding by smoking resulted in an 18% decrease in the adjusted estimated hazard ratio, yet this cannot be verified because smoking was unmeasured. Assumptions underlying this method are described, and a cause-specific proportional hazards model that allows easy implementation using standard software is presented.

  8. Assessment and Indirect Adjustment for Confounding by Smoking in Cohort Studies Using Relative Hazards Models

    PubMed Central

    Richardson, David B.; Laurier, Dominique; Schubauer-Berigan, Mary K.; Tchetgen, Eric Tchetgen; Cole, Stephen R.

    2014-01-01

    Workers' smoking histories are not measured in many occupational cohort studies. Here we discuss the use of negative control outcomes to detect and adjust for confounding in analyses that lack information on smoking. We clarify the assumptions necessary to detect confounding by smoking and the additional assumptions necessary to indirectly adjust for such bias. We illustrate these methods using data from 2 studies of radiation and lung cancer: the Colorado Plateau cohort study (1950–2005) of underground uranium miners (in which smoking was measured) and a French cohort study (1950–2004) of nuclear industry workers (in which smoking was unmeasured). A cause-specific relative hazards model is proposed for estimation of indirectly adjusted associations. Among the miners, the proposed method suggests no confounding by smoking of the association between radon and lung cancer—a conclusion supported by adjustment for measured smoking. Among the nuclear workers, the proposed method suggests substantial confounding by smoking of the association between radiation and lung cancer. Indirect adjustment for confounding by smoking resulted in an 18% decrease in the adjusted estimated hazard ratio, yet this cannot be verified because smoking was unmeasured. Assumptions underlying this method are described, and a cause-specific proportional hazards model that allows easy implementation using standard software is presented. PMID:25245043

  9. The essence of linkage-based imprinting detection: comparing power, type 1 error, and the effects of confounders in two different analysis approaches.

    PubMed

    Greenberg, David A; Monti, Maria Cristina; Feenstra, Bjarke; Zhang, Junying; Hodge, Susan E

    2010-05-01

    Imprinting is critical to understanding disease expression. It can be detected using linkage information, but the effects of potential confounders (heterogeneity, sex-specific penetrance, and sex-biased ascertainment) have not been explored. We examine power and confounders in two imprinting detection approaches, and we explore imprinting-linkage interaction. One method (PP) models imprinting by maximising lod scores w.r.t. parent-specific penetrances. The second (DRF) approximates imprinting by maximising lods over differential male-female recombination fractions. We compared power, type 1 error, and confounder effects in these two methods, using computer-simulated data. We varied heterogeneity, penetrance, family and dataset size, and confounders that might mimic imprinting. Without heterogeneity, PP had more imprinting-detecting power than DRF. PP's power increased when parental affectedness status was ignored, but decreased with heterogeneity. With heterogeneity, type 1 error increased dramatically for both methods. However, DRF's power also increased under heterogeneity, more than was attributable to inflated type 1 error. Sex-specific penetrance could increase false positives for PP but not for DRF. False positives did not increase on ascertainment through an affected "mother". For PP, non-penetrant individuals increased information, arguing against using affected-only methods. The high type 1 error levels under some circumstances means these methods must be used cautiously. PMID:20374235

  10. Natural genetic variability of the neuronal nicotinic acetylcholine receptor subunit genes in mice: Consequences and confounds.

    PubMed

    Wilking, Jennifer A; Stitzel, Jerry A

    2015-09-01

    Recent human genetic studies have identified genetic variants in multiple nicotinic acetylcholine receptor (nAChR) subunit genes that are associated with risk for nicotine dependence and other smoking-related measures. Genetic variability also exists in the nAChR subunit genes in mice. Most studies on mouse nAChR subunit gene variability to date have focused on Chrna4, the gene that encodes the α4 nAChR subunit and Chrna7, the gene that encodes the α7 nAChR subunit. However, genetic variability exists for all nAChR genes in mice. In this review, we will describe what is known about nAChR subunit gene polymorphisms in mice and how it relates to variability in nAChR expression and function in brain. The relationship between nAChR genetic variability in mice and the effects of nicotine on several behavioral and physiological measures also will be discussed. In addition, an overview of the contribution of other genetic variation to nicotine sensitivity in mice will be provided. Finally, the potential for natural genetic variability to confound and/or modify the results of studies that utilize genetically engineered mice will be considered. As an example of the ability of a natural genetic variant to modify the effect of an engineered mutation, data will be presented that demonstrate that the effect of Chrna5 deletion on oral nicotine intake is dependent upon naturally occurring variant alleles of Chrna4. This article is part of the Special Issue entitled 'The Nicotinic Acetylcholine Receptor: From Molecular Biology to Cognition'. PMID:25498233

  11. Confounding environmental colour and distribution shape leads to underestimation of population extinction risk.

    PubMed

    Fowler, Mike S; Ruokolainen, Lasse

    2013-01-01

    The colour of environmental variability influences the size of population fluctuations when filtered through density dependent dynamics, driving extinction risk through dynamical resonance. Slow fluctuations (low frequencies) dominate in red environments, rapid fluctuations (high frequencies) in blue environments and white environments are purely random (no frequencies dominate). Two methods are commonly employed to generate the coloured spatial and/or temporal stochastic (environmental) series used in combination with population (dynamical feedback) models: autoregressive [AR(1)] and sinusoidal (1/f) models. We show that changing environmental colour from white to red with 1/f models, and from white to red or blue with AR(1) models, generates coloured environmental series that are not normally distributed at finite time-scales, potentially confounding comparison with normally distributed white noise models. Increasing variability of sample Skewness and Kurtosis and decreasing mean Kurtosis of these series alter the frequency distribution shape of the realised values of the coloured stochastic processes. These changes in distribution shape alter patterns in the probability of single and series of extreme conditions. We show that the reduced extinction risk for undercompensating (slow growing) populations in red environments previously predicted with traditional 1/f methods is an artefact of changes in the distribution shapes of the environmental series. This is demonstrated by comparison with coloured series controlled to be normally distributed using spectral mimicry. Changes in the distribution shape that arise using traditional methods lead to underestimation of extinction risk in normally distributed, red 1/f environments. AR(1) methods also underestimate extinction risks in traditionally generated red environments. This work synthesises previous results and provides further insight into the processes driving extinction risk in model populations. We must let

  12. Distinguishing prostate cancer from benign confounders via a cascaded classifier on multi-parametric MRI

    NASA Astrophysics Data System (ADS)

    Litjens, G. J. S.; Elliott, R.; Shih, N.; Feldman, M.; Barentsz, J. O.; Hulsbergen-van de Kaa, C. A.; Kovacs, I.; Huisman, H. J.; Madabhushi, A.

    2014-03-01

    Learning how to separate benign confounders from prostate cancer is important because the imaging characteristics of these confounders are poorly understood. Furthermore, the typical representations of the MRI parameters might not be enough to allow discrimination. The diagnostic uncertainty this causes leads to a lower diagnostic accuracy. In this paper a new cascaded classifier is introduced to separate prostate cancer and benign confounders on MRI in conjunction with specific computer-extracted features to distinguish each of the benign classes (benign prostatic hyperplasia (BPH), inflammation, atrophy or prostatic intra-epithelial neoplasia (PIN). In this study we tried to (1) calculate different mathematical representations of the MRI parameters which more clearly express subtle differences between different classes, (2) learn which of the MRI image features will allow to distinguish specific benign confounders from prostate cancer, and (2) find the combination of computer-extracted MRI features to best discriminate cancer from the confounding classes using a cascaded classifier. One of the most important requirements for identifying MRI signatures for adenocarcinoma, BPH, atrophy, inflammation, and PIN is accurate mapping of the location and spatial extent of the confounder and cancer categories from ex vivo histopathology to MRI. Towards this end we employed an annotated prostatectomy data set of 31 patients, all of whom underwent a multi-parametric 3 Tesla MRI prior to radical prostatectomy. The prostatectomy slides were carefully co-registered to the corresponding MRI slices using an elastic registration technique. We extracted texture features from the T2-weighted imaging, pharmacokinetic features from the dynamic contrast enhanced imaging and diffusion features from the diffusion-weighted imaging for each of the confounder classes and prostate cancer. These features were selected because they form the mainstay of clinical diagnosis. Relevant features for

  13. Race and Socioeconomic Status as Confounding Variables in the Accurate Diagnosis of Alcoholism.

    ERIC Educational Resources Information Center

    Luepnitz, Roy R.; And Others

    1982-01-01

    Studied the incidence of bias related to race and socioeconomic status which could confound the diagnosis of alcoholism. Graduate psychology students made a diagnosis based on videotapes. Results indicated lower socioeconomic class individuals were more often diagnosed correctly for alcoholism, and Blacks were diagnosed alcoholic more often than…

  14. Confounding Effects of Metformin on the Human Gut Microbiome in Type 2 Diabetes.

    PubMed

    Mardinoglu, Adil; Boren, Jan; Smith, Ulf

    2016-01-12

    Type 2 diabetes (T2D) is associated with dysbiosis of the gut microbiota, though diabetes treatment regimens, including metformin, may confound the results. Forslund et al. (2015) identify distinct disease and drug signatures and highlight the importance of adjusting for treatment when investigating how T2D influences the human gut microbiome. PMID:26771114

  15. Controlling Time-Dependent Confounding by Health Status and Frailty: Restriction Versus Statistical Adjustment

    PubMed Central

    McGrath, Leah J.; Ellis, Alan R.; Brookhart, M. Alan

    2015-01-01

    Nonexperimental studies of preventive interventions are often biased because of the healthy-user effect and, in frail populations, because of confounding by functional status. Bias is evident when estimating influenza vaccine effectiveness, even after adjustment for claims-based indicators of illness. We explored bias reduction methods while estimating vaccine effectiveness in a cohort of adult hemodialysis patients. Using the United States Renal Data System and linked data from a commercial dialysis provider, we estimated vaccine effectiveness using a Cox proportional hazards marginal structural model of all-cause mortality before and during 3 influenza seasons in 2005/2006 through 2007/2008. To improve confounding control, we added frailty indicators to the model, measured time-varying confounders at different time intervals, and restricted the sample in multiple ways. Crude and baseline-adjusted marginal structural models remained strongly biased. Restricting to a healthier population removed some unmeasured confounding; however, this reduced the sample size, resulting in wide confidence intervals. We estimated an influenza vaccine effectiveness of 9% (hazard ratio = 0.91, 95% confidence interval: 0.72, 1.15) when bias was minimized through cohort restriction. In this study, the healthy-user bias could not be controlled through statistical adjustment; however, sample restriction reduced much of the bias. PMID:25868551

  16. Adjusting for unmeasured confounding due to either of two crossed factors with a logistic regression model.

    PubMed

    Li, Li; Brumback, Babette A; Weppelmann, Thomas A; Morris, J Glenn; Ali, Afsar

    2016-08-15

    Motivated by an investigation of the effect of surface water temperature on the presence of Vibrio cholerae in water samples collected from different fixed surface water monitoring sites in Haiti in different months, we investigated methods to adjust for unmeasured confounding due to either of the two crossed factors site and month. In the process, we extended previous methods that adjust for unmeasured confounding due to one nesting factor (such as site, which nests the water samples from different months) to the case of two crossed factors. First, we developed a conditional pseudolikelihood estimator that eliminates fixed effects for the levels of each of the crossed factors from the estimating equation. Using the theory of U-Statistics for independent but non-identically distributed vectors, we show that our estimator is consistent and asymptotically normal, but that its variance depends on the nuisance parameters and thus cannot be easily estimated. Consequently, we apply our estimator in conjunction with a permutation test, and we investigate use of the pigeonhole bootstrap and the jackknife for constructing confidence intervals. We also incorporate our estimator into a diagnostic test for a logistic mixed model with crossed random effects and no unmeasured confounding. For comparison, we investigate between-within models extended to two crossed factors. These generalized linear mixed models include covariate means for each level of each factor in order to adjust for the unmeasured confounding. We conduct simulation studies, and we apply the methods to the Haitian data. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26892025

  17. Confounding Effects of Metformin on the Human Gut Microbiome in Type 2 Diabetes.

    PubMed

    Mardinoglu, Adil; Boren, Jan; Smith, Ulf

    2016-01-12

    Type 2 diabetes (T2D) is associated with dysbiosis of the gut microbiota, though diabetes treatment regimens, including metformin, may confound the results. Forslund et al. (2015) identify distinct disease and drug signatures and highlight the importance of adjusting for treatment when investigating how T2D influences the human gut microbiome.

  18. Assessing Mediation Using Marginal Structural Models in the Presence of Confounding and Moderation

    ERIC Educational Resources Information Center

    Coffman, Donna L.; Zhong, Wei

    2012-01-01

    This article presents marginal structural models with inverse propensity weighting (IPW) for assessing mediation. Generally, individuals are not randomly assigned to levels of the mediator. Therefore, confounders of the mediator and outcome may exist that limit causal inferences, a goal of mediation analysis. Either regression adjustment or IPW…

  19. Confounds in Assessing the Associations between Biliteracy and English Language Proficiency

    ERIC Educational Resources Information Center

    Proctor, C. Patrick; Silverman, Rebecca D.

    2011-01-01

    It has long been theorized, if not exhaustively researched, that bilingualism and biliteracy are beneficial in promoting linguistic and academic gains; but the operationalization of these constructs is confounding. In the current study, the authors worked with 118 Spanish-English bilingual Latina/o students and investigated whether Spanish-English…

  20. An education gradient in health, a health gradient in education, or a confounded gradient in both?

    PubMed

    Lynch, Jamie L; von Hippel, Paul T

    2016-04-01

    There is a positive gradient associating educational attainment with health, yet the explanation for this gradient is not clear. Does higher education improve health (causation)? Do the healthy become highly educated (selection)? Or do good health and high educational attainment both result from advantages established early in the life course (confounding)? This study evaluates these competing explanations by tracking changes in educational attainment and Self-rated Health (SRH) from age 15 to age 31 in the National Longitudinal Study of Youth, 1997 cohort. Ordinal logistic regression confirms that high-SRH adolescents are more likely to become highly educated. This is partly because adolescent SRH is associated with early advantages including adolescents' academic performance, college plans, and family background (confounding); however, net of these confounders adolescent SRH still predicts adult educational attainment (selection). Fixed-effects longitudinal regression shows that educational attainment has little causal effect on SRH at age 31. Completion of a high school diploma or associate's degree has no effect on SRH, while completion of a bachelor's or graduate degree have effects that, though significant, are quite small (less than 0.1 points on a 5-point scale). While it is possible that educational attainment would have greater effect on health at older ages, at age 31 what we see is a health gradient in education, shaped primarily by selection and confounding rather than by a causal effect of education on health.

  1. Combating Unmeasured Confounding in Cross-Sectional Studies: Evaluating Instrumental-Variable and Heckman Selection Models

    PubMed Central

    DeMaris, Alfred

    2014-01-01

    Unmeasured confounding is the principal threat to unbiased estimation of treatment “effects” (i.e., regression parameters for binary regressors) in nonexperimental research. It refers to unmeasured characteristics of individuals that lead them both to be in a particular “treatment” category and to register higher or lower values than others on a response variable. In this article, I introduce readers to 2 econometric techniques designed to control the problem, with a particular emphasis on the Heckman selection model (HSM). Both techniques can be used with only cross-sectional data. Using a Monte Carlo experiment, I compare the performance of instrumental-variable regression (IVR) and HSM to that of ordinary least squares (OLS) under conditions with treatment and unmeasured confounding both present and absent. I find HSM generally to outperform IVR with respect to mean-square-error of treatment estimates, as well as power for detecting either a treatment effect or unobserved confounding. However, both HSM and IVR require a large sample to be fully effective. The use of HSM and IVR in tandem with OLS to untangle unobserved confounding bias in cross-sectional data is further demonstrated with an empirical application. Using data from the 2006–2010 General Social Survey (National Opinion Research Center, 2014), I examine the association between being married and subjective well-being. PMID:25110904

  2. Accounting for time-dependent covariates whose levels are influenced by exposure status.

    PubMed

    Weiss, N S; Dublin, S

    1998-07-01

    When measuring the association between an exposure and disease, one must decide whether to account for confounding or modifying variables whose levels are altered by the presence of the exposure. For example, to assess the impact of cessation of unopposed estrogen therapy on the occurrence of endometrial cancer, a researcher needs to consider the duration of the estrogen therapy, a strong risk factor for endometrial cancer, as a potential confounder or effect modifier. Duration of estrogen therapy, however, is itself influenced by the decision to stop the therapy (the "exposure" of interest). In such a case, two distinct approaches may be taken, depending upon the question being considered. One may wish to assess the degree to which the exposure predicts disease incidence, over and above the additional variable, at some later point in time. In this case, it is appropriate to consider the value of the other variable (for example, duration) at that later time. On the other hand, one may also wish to measure the rate of disease beginning at the time of cessation of the exposure, relative to the corresponding rate in persons with continuing exposure Here, the most appropriate analysis considers the level of the confounding variable (for example, duration) measured only until the time of exposure of interest occurs (for example, cessation of unopposed estrogen therapy). Examples are given to illustrate that the specific question being addressed dictates the handling of covariates of this type. PMID:9647909

  3. Timing of human preimplantation embryonic development is confounded by embryo origin

    PubMed Central

    Kirkegaard, K.; Sundvall, L.; Erlandsen, M.; Hindkjær, J.J.; Knudsen, U.B.; Ingerslev, H.J.

    2016-01-01

    STUDY QUESTION To what extent do patient- and treatment-related factors explain the variation in morphokinetic parameters proposed as embryo viability markers? SUMMARY ANSWER Up to 31% of the observed variation in timing of embryo development can be explained by embryo origin, but no single factor elicits a systematic influence. WHAT IS KNOWN ALREADY Several studies report that culture conditions, patient characteristics and treatment influence timing of embryo development, which have promoted the perception that each clinic must develop individual models. Most of the studies have, however, treated embryos from one patient as independent observations, and only very few studies that evaluate the influence from patient- and treatment-related factors on timing of development or time-lapse parameters as predictors of viability have controlled for confounding, which implies a high risk of overestimating the statistical significance of potential correlations. STUDY DESIGN, SIZE, DURATION Infertile patients were prospectively recruited to a cohort study at a hospital fertility clinic from February 2011 to May 2013. Patients aged <38 years without endometriosis were eligible if ≥8 oocytes were retrieved. Patients were included only once. All embryos were monitored for 6 days in a time-lapse incubator. PARTICIPANTS/MATERIALS, SETTING, METHODS A total of 1507 embryos from 243 patients were included. The influence of fertilization method, BMI, maternal age, FSH dose and number of previous cycles on timing of t2-t5, duration of the 2- and 3-cell stage, and development of a blastocoel (tEB) and full blastocoel (tFB) was tested in multivariate, multilevel linear regression analysis. Predictive parameters for live birth were tested in a logistic regression analysis for 223 single transferred blastocysts, where time-lapse parameters were investigated along with patient and embryo characteristics. MAIN RESULTS AND THE ROLE OF CHANCE Moderate intra-class correlation coefficients

  4. Histopathological baseline levels and confounding factors in common sole (Solea solea) for marine environmental risk assessment.

    PubMed

    Cuevas, N; Zorita, I; Costa, P M; Larreta, J; Franco, J

    2015-09-01

    Liver and gonad histopathology, biometric parameters and hepatic metal bioaccumulation were assessed monthly over a one-year period in common soles from the Basque continental shelf, in order to determine baseline levels and confounding factors within biomonitoring studies. Biometric parameters and hepatic metal bioaccumulation varied according to season and gender. Accordingly, hepatic histopathological traits presented seasonal variations related to the reproductive cycle. However, the hepatic histopathological index showed that seasonality and gender were not significant confounding factors. Conversely, the gonad histopathological index was modulated by season and gender. As for organ comparison, the liver endured more severe histopathological damage than the gonad. In brief, the sampling period and gender may not affect the estimation of hepatic histopathological indices for biomonitoring purposes. Nonetheless, due to different sensitivities to environmental 'noise' variables, the sampling period and gender differentiation should be thoroughly considered for the assessment of gonad histopathology, biometrics and metal bioaccumulation. PMID:26364682

  5. In vivo measurement of 241Am in the lungs confounded by activity deposited in other organs.

    PubMed

    Lobaugh, Megan L; Spitz, Henry B; Glover, Samuel E

    2015-01-01

    Radioactive material deposited in multiple organs of the body is likely to confound a result of an in vivo measurement performed over the lungs, the most frequently monitored organ for occupational exposure. The significance of this interference was evaluated by measuring anthropometric torso phantoms containing lungs, liver, skeleton, and axillary lymph nodes, each with a precisely known quantity of 241Am uniformly distributed in the organs. Arrays of multiple high-resolution germanium detectors were positioned over organs within the torso phantom containing 241Am or over proximal organs without activity to determine the degree of measurement confounding due to photons emitted from other source organs. A set of four mathematical response functions describes the measured count rate with detectors positioned over each of the relevant organs and 241Am contained in the measured organ or one of the other organs selected as a confounder. Simultaneous solution of these equations by matrix algebra, where the diagonal terms of the matrix are calibration factors for a direct measurement of activity in an organ and the off-diagonal terms reflect the contribution (i.e., interference or cross-talk) produced by 241Am in a confounding organ, yields the activity deposited in each of the relevant organs. The matrix solution described in this paper represents a method for adjusting a result of 241Am measured directly in one organ for interferences that may arise from 241Am deposited elsewhere and represents a technically valid procedure to aid in evaluating internal dose based upon in vivo measurements for those radioactive materials known to deposit in multiple organs.

  6. In vivo measurement of 241Am in the lungs confounded by activity deposited in other organs.

    PubMed

    Lobaugh, Megan L; Spitz, Henry B; Glover, Samuel E

    2015-01-01

    Radioactive material deposited in multiple organs of the body is likely to confound a result of an in vivo measurement performed over the lungs, the most frequently monitored organ for occupational exposure. The significance of this interference was evaluated by measuring anthropometric torso phantoms containing lungs, liver, skeleton, and axillary lymph nodes, each with a precisely known quantity of 241Am uniformly distributed in the organs. Arrays of multiple high-resolution germanium detectors were positioned over organs within the torso phantom containing 241Am or over proximal organs without activity to determine the degree of measurement confounding due to photons emitted from other source organs. A set of four mathematical response functions describes the measured count rate with detectors positioned over each of the relevant organs and 241Am contained in the measured organ or one of the other organs selected as a confounder. Simultaneous solution of these equations by matrix algebra, where the diagonal terms of the matrix are calibration factors for a direct measurement of activity in an organ and the off-diagonal terms reflect the contribution (i.e., interference or cross-talk) produced by 241Am in a confounding organ, yields the activity deposited in each of the relevant organs. The matrix solution described in this paper represents a method for adjusting a result of 241Am measured directly in one organ for interferences that may arise from 241Am deposited elsewhere and represents a technically valid procedure to aid in evaluating internal dose based upon in vivo measurements for those radioactive materials known to deposit in multiple organs. PMID:25437522

  7. Cryptic confounding compounds: A brief consideration of the influences of anthropogenic contaminants on courtship and mating behavior

    PubMed Central

    Blocker, Tomica D.; Ophir, Alexander G.

    2012-01-01

    Contaminants, like pesticides, polychlorinated biphenyls (PCBs), dioxins and metals, are persistent and ubiquitous and are known to threaten the environment. Traditionally, scientists have considered the direct physiological risks that these contaminants pose. However, scientists have just begun to integrate ethology and toxicology to investigate the effects that contaminants have on behavior. This review considers the potential for contaminant effects on mating behavior. Here we assess the growing body of research concerning disruptions in sexual differentiation, courtship, sexual receptivity, arousal, and mating. We discuss the implications of these disruptions on conservation efforts and highlight the importance of recognizing the potential for environmental stressors to affect behavioral experimentation. More specifically, we consider the negative implications for anthropogenic contaminants to affect the immediate behavior of animals, and their potential to have cascading and/or long-term effects on the behavioral ecology and evolution of populations. Overall, we aim to raise awareness of the confounding influence that contaminants can have, and promote caution when interpreting results where the potential for cryptic affects are possible. PMID:24244068

  8. Cryptic confounding compounds: A brief consideration of the influences of anthropogenic contaminants on courtship and mating behavior.

    PubMed

    Blocker, Tomica D; Ophir, Alexander G

    2013-06-01

    Contaminants, like pesticides, polychlorinated biphenyls (PCBs), dioxins and metals, are persistent and ubiquitous and are known to threaten the environment. Traditionally, scientists have considered the direct physiological risks that these contaminants pose. However, scientists have just begun to integrate ethology and toxicology to investigate the effects that contaminants have on behavior. This review considers the potential for contaminant effects on mating behavior. Here we assess the growing body of research concerning disruptions in sexual differentiation, courtship, sexual receptivity, arousal, and mating. We discuss the implications of these disruptions on conservation efforts and highlight the importance of recognizing the potential for environmental stressors to affect behavioral experimentation. More specifically, we consider the negative implications for anthropogenic contaminants to affect the immediate behavior of animals, and their potential to have cascading and/or long-term effects on the behavioral ecology and evolution of populations. Overall, we aim to raise awareness of the confounding influence that contaminants can have, and promote caution when interpreting results where the potential for cryptic affects are possible.

  9. The determinants of actinic skin damage: problems of confounding among environmental and constitutional variables.

    PubMed

    Holman, C D; Evans, P R; Lumsden, G J; Armstrong, B K

    1984-09-01

    Constitutional and environmental determinants of actinic skin damage, assessed by cutaneous microtopography, were evaluated in 1,216 subjects attending the 1981 Busselton Health Survey in Western Australia. Increasing age, male sex, the tendency to burn on exposure to sunlight and outdoor occupation were found to have independent predictive value for the presence of actinic skin damage. Crude positive and inverse associations of actinic skin damage with several other factors were shown to arise from confounding. Effect measures for outdoor leisure pursuits and sunscreen use were underestimated due to inverse associations of these factors with older age, and inverse associations of high-exposure outdoor activities with poor skin response to sunlight. Associations of constitutional traits typical of fair individuals and sunscreen use with the tendency to burn resulted in overestimation of effect measures. Empirical relationships of actinic skin damage with certain leisure activities and with use of sunscreens were also confounded by sex. The results indicate a need for greater attention to confounding in nonexperimental skin cancer research.

  10. Automated isolation of translational efficiency bias that resists the confounding effect of GC(AT)-content.

    PubMed

    Raiford, Douglas W; Krane, Dan E; Doom, Travis E; Raymer, Michael L

    2010-01-01

    Genomic sequencing projects are an abundant source of information for biological studies ranging from the molecular to the ecological in scale; however, much of the information present may yet be hidden from casual analysis. One such information domain, trends in codon usage, can provide a wealth of information about an organism's genes and their expression. Degeneracy in the genetic code allows more than one triplet codon to code for the same amino acid, and usage of these codons is often biased such that one or more of these synonymous codons are preferred. Detection of this bias is an important tool in the analysis of genomic data, particularly as a predictor of gene expressivity. Methods for identifying codon usage bias in genomic data that rely solely on genomic sequence data are susceptible to being confounded by the presence of several factors simultaneously influencing codon selection. Presented here is a new technique for removing the effects of one of the more common confounding factors, GC(AT)-content, and of visualizing the search-space for codon usage bias through the use of a solution landscape. This technique successfully isolates expressivity-related codon usage trends, using only genomic sequence information, where other techniques fail due to the presence of GC(AT)-content confounding influences.

  11. Why Do Thin People Have Elevated All-Cause Mortality? Evidence on Confounding and Reverse Causality in the Association of Adiposity and COPD from the British Women’s Heart and Health Study

    PubMed Central

    Dale, Caroline; Nüesch, Eveline; Prieto-Merino, David; Choi, Minkyoung; Amuzu, Antoinette; Ebrahim, Shah; Casas, Juan P.; Davey-Smith, George

    2015-01-01

    Low adiposity has been linked to elevated mortality from several causes including respiratory disease. However, this could arise from confounding or reverse causality. We explore the association between two measures of adiposity (BMI and WHR) with COPD in the British Women’s Heart and Health Study including a detailed assessment of the potential for confounding and reverse causality for each adiposity measure. Low BMI was found to be associated with increased COPD risk while low WHR was not (OR = 2.2; 95% CI 1.3 – 3.1 versus OR = 1.2; 95% CI 0.7 – 1.6). Potential confounding variables (e.g. smoking) and markers of ill-health (e.g. unintentional weight loss) were found to be higher in low BMI but not in low WHR. Women with low BMI have a detrimental profile across a broad range of health markers compared to women with low WHR, and women with low WHR do not appear to have an elevated COPD risk, lending support to the hypothesis that WHR is a less confounded measure of adiposity than BMI. Low adiposity does not in itself appear to increase the risk of respiratory disease, and the apparent adverse consequences of low BMI may be due to reverse causation and confounding. PMID:25884834

  12. Why do thin people have elevated all-cause mortality? Evidence on confounding and reverse causality in the association of adiposity and COPD from the British Women's Heart and Health Study.

    PubMed

    Dale, Caroline; Nüesch, Eveline; Prieto-Merino, David; Choi, Minkyoung; Amuzu, Antoinette; Ebrahim, Shah; Casas, Juan P; Davey-Smith, George

    2015-01-01

    Low adiposity has been linked to elevated mortality from several causes including respiratory disease. However, this could arise from confounding or reverse causality. We explore the association between two measures of adiposity (BMI and WHR) with COPD in the British Women's Heart and Health Study including a detailed assessment of the potential for confounding and reverse causality for each adiposity measure. Low BMI was found to be associated with increased COPD risk while low WHR was not (OR = 2.2; 95% CI 1.3-3.1 versus OR = 1.2; 95% CI 0.7-1.6). Potential confounding variables (e.g. smoking) and markers of ill-health (e.g. unintentional weight loss) were found to be higher in low BMI but not in low WHR. Women with low BMI have a detrimental profile across a broad range of health markers compared to women with low WHR, and women with low WHR do not appear to have an elevated COPD risk, lending support to the hypothesis that WHR is a less confounded measure of adiposity than BMI. Low adiposity does not in itself appear to increase the risk of respiratory disease, and the apparent adverse consequences of low BMI may be due to reverse causation and confounding.

  13. Accountability Overboard

    ERIC Educational Resources Information Center

    Chieppo, Charles D.; Gass, James T.

    2009-01-01

    This article reports that special interest groups opposed to charter schools and high-stakes testing have hijacked Massachusetts's once-independent board of education and stand poised to water down the Massachusetts Comprehensive Assessment System (MCAS) tests and the accountability system they support. President Barack Obama and Massachusetts…

  14. Painless Accountability.

    ERIC Educational Resources Information Center

    Brown, R. W.; And Others

    The computerized Painless Accountability System is a performance objective system from which instructional programs are developed. Three main simplified behavioral response levels characterize this system: (1) cognitive, (2) psychomotor, and (3) affective domains. Each of these objectives are classified by one of 16 descriptors. The second major…

  15. Accounting Specialist.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. Center on Education and Training for Employment.

    This publication identifies 20 subjects appropriate for use in a competency list for the occupation of accounting specialist, 1 of 12 occupations within the business/computer technologies cluster. Each unit consists of a number of competencies; a list of competency builders is provided for each competency. Titles of the 20 units are as follows:…

  16. Confounding factors to predict the awakening effect-site concentration of propofol in target-controlled infusion based on propofol and fentanyl anesthesia.

    PubMed

    Chan, Shun-Ming; Lee, Meei-Shyuan; Lu, Chueng-He; Cherng, Chen-Hwan; Huang, Yuan-Shiou; Yeh, Chun-Chang; Kuo, Chan-Yang; Wu, Zhi-Fu

    2015-01-01

    We conducted a large retrospective study to investigate the confounding factors that predict Ce ROC under propofol-based TIVA with TCI. We recorded sex, age, height, weight, Ce LOC, Ce ROC, total propofol and fentanyl consumption dose, and anesthetic time. Simple linear regression models were used to identify potential predictors of Ce ROC, and multiple linear regression models were used to identify the confounding predictors of Ce ROC. We found that Ce ROC correlated with age, sex, Ce LOC, and both total fentanyl and propofol consumption dose. The prediction formula was: Ce ROC = 0.87 - 0.06 × age + 0.18 × Ce LOC + 0.04 (if fentanyl consumption > 150 μg; if not, ignore this value) + 0.07 × (1 or 2, according to the total propofol consumption dose, 1 for a propofol amount 1000-2000 mg and 2 for a propofol amount > 2000 mg). We simplified the formula further as Ce ROC = 0.87 - 0.06 × age + 0.18 × Ce LOC. In conclusion, Ce ROC can be predicted under TCI with propofol- and fentanyl-based TIVA. The confounding factors that predicted propofol Ce ROC are age, sex, Ce LOC, and total consumption dose of propofol and fentanyl.

  17. Teacher Quality at the High-School Level: The Importance of Accounting for Tracks. Working Paper 17722. Revised

    ERIC Educational Resources Information Center

    Jackson, C. Kirabo

    2013-01-01

    Unlike in elementary school, high-school teacher effects may be confounded with both selection to tracks and unobserved track-level treatments. I document sizable confounding track effects, and show that traditional tests for the existence of teacher effects are likely biased. After accounting for these biases, high-school algebra and English…

  18. Pulmonary impairment in a cotton textile factory in Nigeria: is lifetime alcohol intake with low cigarette smoking a confounding factor?

    PubMed

    Oleru, U G

    1987-01-01

    A study of 60 Nigerian workers who seldom smoked and who were exposed for 2-15 yr in the printing, dyeing, and maintenance sections of a cotton textile factory showed a 38% airway and 20% "probably airway" symptoms. The airway symptoms were significantly (p less than .005) associated with a decrement in spirometric lung function before and after adjustment for age, height, and duration of employment. The change in residual pulmonary function (PFT) per year of employment was three times higher for the subjects with airway symptoms than for subjects presenting no symptoms. Lifetime alcohol intake was significantly (.025 greater than p less than .01) negatively correlated with pulmonary function and obstructive and restrictive lung disease parameters. Together with body weight, alcohol bottle-years accounted for between 18 and 22% of the variation in lung function, in a forward and reverse stepwise regression analysis. When duration of employment was standardized, subjects with considerable alcohol intake had significantly (.025 greater than p less than .005) lower pulmonary function before and after adjustment for age and height. When the residual PFT was further adjusted for duration of employment, the subjects with higher alcohol intake had significantly (.01 greater than p less than .005) higher residual per year of employment. The subjects presenting airway symptoms had significantly (.05 greater than p less than .005) higher alcohol intake than those in other symptom categories. These data suggest that alcohol intake is a probable confounder in the observed airway and PFT changes.

  19. Fluctuating estuarine conditions are not confounding factors for the Comet assay assessment of DNA damage in the mussel Mytilus edulis.

    PubMed

    Singh, Rupika; Hartl, Mark G J

    2012-10-01

    The Comet assay is finding increasing application as a biomarker assay for the genotoxic potential of contaminants in field transplantation experiments involving mussels. Especially in estuaries, habitats that are of particular concern, environmental variables, such as salinity, can vary significantly. Although hinted at in the literature, there is a lack of clarification as to whether changes in salinity or emersion-induced hypoxia have the potential to alter background DNA damage in mussels, thus masking the extent of potential genotoxic effects following exposure to environmental contaminants. The present study exposed Mytilus edulis in the laboratory to static salinities (25, 50, 75, and 100 %) for 72 h. Mussels were also subjected to simulated tidal cycles, including periods of emersion, for 72 h. None of these treatments resulted in a significant change in the level of DNA damage expressed as % tail DNA. These experiments demonstrate that salinity, within the limits of the concentrations tested, and temporary emersion are not confounding factors for Comet assay data derived from M. edulis.

  20. Confronting ‘confounding by health system use’ in Medicare Part D: Comparative effectiveness of propensity score approaches to confounding adjustment

    PubMed Central

    Polinski, Jennifer M.; Schneeweiss, Sebastian; Glynn, Robert J.; Lii, Joyce; Rassen, Jeremy

    2012-01-01

    Purpose Under Medicare Part D, patient characteristics influence plan choice, which in turn influences Part D coverage gap entry. We compared pre-defined propensity score (PS) and high-dimensional propensity score (hdPS) approaches to address such ‘confounding by health system use’ in assessing whether coverage gap entry is associated with cardiovascular events or death. Methods We followed 243,079 Medicare patients aged 65+ with linked prescription, medical, and plan-specific data in 2005–2007. Patients reached the coverage gap and were followed until an event or year’s end. Exposed patients were responsible for drug costs in the gap; unexposed patients (patients with non-Part D drug insurance and Part D patients receiving a low-income subsidy (LIS)) received financial assistance. Exposed patients were 1:1 PS- or hdPS-matched to unexposed patients. The PS model included 52 predefined covariates; the hdPS model added 400 empirically identified covariates. Hazard ratios for death and any of five cardiovascular outcomes were compared. In sensitivity analyses, we explored residual confounding using only LIS patients in the unexposed group. Results In unadjusted analyses, exposed patients had no greater hazard of death (HR=1.00; 95% CI, 0.84–1.20) or other outcomes. PS- (HR=1.29;0.99–1.66) and hdPS- (HR=1.11;0.86–1.42) matched analyses showed elevated but non-significant hazards of death. In sensitivity analyses, the PS analysis showed a protective effect (HR=0.78;0.61–0.98), while the hdPS analysis (HR=1.06;0.82–1.37) confirmed the main hdPS findings. Conclusion Although the PS-matched analysis suggested elevated though non-significant hazards of death among patients with no financial assistance during the gap, the hdPS analysis produced lower estimates that were stable across sensitivity analyses. PMID:22552984

  1. 12 CFR 707.4 - Account disclosures.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 7 2013-01-01 2013-01-01 false Account disclosures. 707.4 Section 707.4 Banks... § 707.4 Account disclosures. (a) Delivery of account disclosures—(1) Account opening. (i) General. A credit union must provide account disclosures to a member or potential member before an account is...

  2. 12 CFR 707.4 - Account disclosures.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 7 2014-01-01 2014-01-01 false Account disclosures. 707.4 Section 707.4 Banks... § 707.4 Account disclosures. (a) Delivery of account disclosures—(1) Account opening. (i) General. A credit union must provide account disclosures to a member or potential member before an account is...

  3. 12 CFR 707.4 - Account disclosures.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 7 2012-01-01 2012-01-01 false Account disclosures. 707.4 Section 707.4 Banks... § 707.4 Account disclosures. (a) Delivery of account disclosures—(1) Account opening. (i) General. A credit union must provide account disclosures to a member or potential member before an account is...

  4. 12 CFR 239.62 - Liquidation accounts.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 4 2012-01-01 2012-01-01 false Liquidation accounts. 239.62 Section 239.62... Liquidation accounts. (a) Liquidation account.(1) A liquidation account represents the potential interest of eligible account holders and supplemental eligible account holders in the mutual holding company's...

  5. 12 CFR 239.62 - Liquidation accounts.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 4 2013-01-01 2013-01-01 false Liquidation accounts. 239.62 Section 239.62... Liquidation accounts. (a) Liquidation account. (1) A liquidation account represents the potential interest of eligible account holders and supplemental eligible account holders in the mutual holding company's...

  6. 12 CFR 239.62 - Liquidation accounts.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 4 2014-01-01 2014-01-01 false Liquidation accounts. 239.62 Section 239.62... Liquidation accounts. (a) Liquidation account. (1) A liquidation account represents the potential interest of eligible account holders and supplemental eligible account holders in the mutual holding company's...

  7. A powerful and efficient set test for genetic markers that handles confounders

    PubMed Central

    Listgarten, Jennifer; Lippert, Christoph; Kang, Eun Yong; Xiang, Jing; Kadie, Carl M.; Heckerman, David

    2013-01-01

    Motivation: Approaches for testing sets of variants, such as a set of rare or common variants within a gene or pathway, for association with complex traits are important. In particular, set tests allow for aggregation of weak signal within a set, can capture interplay among variants and reduce the burden of multiple hypothesis testing. Until now, these approaches did not address confounding by family relatedness and population structure, a problem that is becoming more important as larger datasets are used to increase power. Results: We introduce a new approach for set tests that handles confounders. Our model is based on the linear mixed model and uses two random effects—one to capture the set association signal and one to capture confounders. We also introduce a computational speedup for two random-effects models that makes this approach feasible even for extremely large cohorts. Using this model with both the likelihood ratio test and score test, we find that the former yields more power while controlling type I error. Application of our approach to richly structured Genetic Analysis Workshop 14 data demonstrates that our method successfully corrects for population structure and family relatedness, whereas application of our method to a 15 000 individual Crohn’s disease case–control cohort demonstrates that it additionally recovers genes not recoverable by univariate analysis. Availability: A Python-based library implementing our approach is available at http://mscompbio.codeplex.com. Contact: jennl@microsoft.com or lippert@microsoft.com or heckerma@microsoft.com Supplementary information: Supplementary data are available at Bioinformatics online. PMID:23599503

  8. A comparison of confounding adjustment methods with an application to early life determinants of childhood obesity

    PubMed Central

    Kleinman, Ken; Gillman, Matthew W.

    2014-01-01

    We implemented 6 confounding adjustment methods: 1) covariate-adjusted regression, 2) propensity score (PS) regression, 3) PS stratification, 4) PS matching with two calipers, 5) inverse-probability-weighting, and 6) doubly-robust estimation to examine the associations between the BMI z-score at 3 years and two separate dichotomous exposure measures: exclusive breastfeeding versus formula only (N = 437) and cesarean section versus vaginal delivery (N = 1236). Data were drawn from a prospective pre-birth cohort study, Project Viva. The goal is to demonstrate the necessity and usefulness, and approaches for multiple confounding adjustment methods to analyze observational data. Unadjusted (univariate) and covariate-adjusted linear regression associations of breastfeeding with BMI z-score were −0.33 (95% CI −0.53, −0.13) and −0.24 (−0.46, −0.02), respectively. The other approaches resulted in smaller N (204 to 276) because of poor overlap of covariates, but CIs were of similar width except for inverse-probability-weighting (75% wider) and PS matching with a wider caliper (76% wider). Point estimates ranged widely, however, from −0.01 to −0.38. For cesarean section, because of better covariate overlap, the covariate-adjusted regression estimate (0.20) was remarkably robust to all adjustment methods, and the widths of the 95% CIs differed less than in the breastfeeding example. Choice of covariate adjustment method can matter. Lack of overlap in covariate structure between exposed and unexposed participants in observational studies can lead to erroneous covariate-adjusted estimates and confidence intervals. We recommend inspecting covariate overlap and using multiple confounding adjustment methods. Similar results bring reassurance. Contradictory results suggest issues with either the data or the analytic method. PMID:25171142

  9. Confounding factors in using upward feedback to assess the quality of medical training: a systematic review

    PubMed Central

    2014-01-01

    Purpose: Upward feedback is becoming more widely used in medical training as a means of quality control. Multiple biases exist, thus the accuracy of upward feedback is debatable. This study aims to identify factors that could influence upward feedback, especially in medical training. Methods: A systematic review using a structured search strategy was performed. Thirty-five databases were searched. Results were reviewed and relevant abstracts were shortlisted. All studies in English, both medical and non-medical literature, were included. A simple pro-forma was used initially to identify the pertinent areas of upward feedback, so that a focused pro-forma could be designed for data extraction. Results: A total of 204 articles were reviewed. Most studies on upward feedback bias were evaluative studies and only covered Kirkpatrick level 1-reaction. Most studies evaluated trainers or training, were used for formative purposes and presented quantitative data. Accountability and confidentiality were the most common overt biases, whereas method of feedback was the most commonly implied bias within articles. Conclusion: Although different types of bias do exist, upward feedback does have a role in evaluating medical training. Accountability and confidentiality were the most common biases. Further research is required to evaluate which types of bias are associated with specific survey characteristics and which are potentially modifiable. PMID:25112445

  10. Unknown age in health disorders: A method to account for its cumulative effect and an application to feline viruses interactions.

    PubMed

    Hellard, Eléonore; Pontier, Dominique; Siberchicot, Aurélie; Sauvage, Frank; Fouchet, David

    2015-06-01

    Parasite interactions have been widely evidenced experimentally but field studies remain rare. Such studies are essential to detect interactions of interest and access (co)infection probabilities but face methodological obstacles. Confounding factors can create statistical associations, i.e. false parasite interactions. Among them, host age is a crucial covariate. It influences host exposition and susceptibility to many infections, and has a mechanical effect, older individuals being more at risk because of a longer exposure time. However, age is difficult to estimate in natural populations. Hence, one should be able to deal at least with its cumulative effect. Using a SI type dynamic model, we showed that the cumulative effect of age can generate false interactions theoretically (deterministic modeling) and with a real dataset of feline viruses (stochastic modeling). The risk to wrongly conclude to an association was maximal when parasites induced long-lasting antibodies and had similar forces of infection. We then proposed a method to correct for this effect (and for other potentially confounding shared risk factors) and made it available in a new R package, Interatrix. We also applied the correction to the feline viruses. It offers a way to account for an often neglected confounding factor and should help identifying parasite interactions in the field, a necessary step towards a better understanding of their mechanisms and consequences. PMID:25979281

  11. On the causal interpretation of race in regressions adjusting for confounding and mediating variables.

    PubMed

    VanderWeele, Tyler J; Robinson, Whitney R

    2014-07-01

    We consider several possible interpretations of the "effect of race" when regressions are run with race as an exposure variable, controlling also for various confounding and mediating variables. When adjustment is made for socioeconomic status early in a person's life, we discuss under what contexts the regression coefficients for race can be interpreted as corresponding to the extent to which a racial inequality would remain if various socioeconomic distributions early in life across racial groups could be equalized. When adjustment is also made for adult socioeconomic status, we note how the overall racial inequality can be decomposed into the portion that would be eliminated by equalizing adult socioeconomic status across racial groups and the portion of the inequality that would remain even if adult socioeconomic status across racial groups were equalized. We also discuss a stronger interpretation of the effect of race (stronger in terms of assumptions) involving the joint effects of race-associated physical phenotype (eg, skin color), parental physical phenotype, genetic background, and cultural context when such variables are thought to be hypothetically manipulable and if adequate control for confounding were possible. We discuss some of the challenges with such an interpretation. Further discussion is given as to how the use of selected populations in examining racial disparities can additionally complicate the interpretation of the effects.

  12. On causal interpretation of race in regressions adjusting for confounding and mediating variables

    PubMed Central

    VanderWeele, Tyler J.; Robinson, Whitney R.

    2014-01-01

    We consider several possible interpretations of the “effect of race” when regressions are run with race as an exposure variable, controlling also for various confounding and mediating variables. When adjustment is made for socioeconomic status early in a person’s life, we discuss under what contexts the regression coefficients for race can be interpreted as corresponding to the extent to which a racial inequality would remain if various socioeconomic distributions early in life across racial groups could be equalized. When adjustment is also made for adult socioeconomic status, we note how the overall racial inequality can be decomposed into the portion that would be eliminated by equalizing adult socioeconomic status across racial groups and the portion of the inequality that would remain even if adult socioeconomic status across racial groups were equalized. We also discuss a stronger interpretation of the “effect of race” (stronger in terms of assumptions) involving the joint effects of race-associated physical phenotype (e.g. skin color), parental physical phenotype, genetic background and cultural context when such variables are thought to be hypothetically manipulable and if adequate control for confounding were possible. We discuss some of the challenges with such an interpretation. Further discussion is given as to how the use of selected populations in examining racial disparities can additionally complicate the interpretation of the effects. PMID:24887159

  13. The effect of 5-fluorouracil/leucovorin chemotherapy on CpG methylation, or the confounding role of leukocyte heterogeneity: An illustration.

    PubMed

    Lemire, Mathieu; Zaidi, Syed H E; Zanke, Brent W; Gallinger, Steven; Hudson, Thomas J; Cleary, Sean P

    2015-12-01

    Blood-based epigenome-wide association studies that aim at comparing CpG methylation between colorectal cancer (CRC) patients and controls can lead to the discovery of diagnostic or prognostic biomarkers. Numerous confounders can lead to spurious associations. We aimed to see if 5-fluorouracil (5-FU)/leucovorin chemotherapy administered to cases prior to the collection of their blood has an effect on methylation. 304 patients who received treatment and 273 who did not were profiled on the HumanMethylation450 array. Association tests were adjusted for confounders, including proxies for leukocyte cell counts. There were substantial methylation differences between these two groups that vanished once the leukocyte heterogeneity was accounted for. We observed a significant decrease of T cells in the treatment group (CD4+: p=10(-6); CD8+: p=0.036) and significant increase of NK cells (p=0.05) and monocytes (p=0.0006). 5-FU/leucovorin has no effect on global and local blood-based methylation profiles, other than through differences in the leukocyte compositions that the treatment induced.

  14. Proteasome inhibitor model of Parkinson's disease in mice is confounded by neurotoxicity of the ethanol vehicle.

    PubMed

    Landau, Anne M; Kouassi, Edouard; Siegrist-Johnstone, Rosmarie; Desbarats, Julie

    2007-02-15

    Defects in the ubiquitin-proteasome system have been implicated in Parkinson's Disease (PD). Recently, a rat model of PD was developed using a synthetic proteasome inhibitor (PSI), (Z-lle-Glu(OtBu)-Ala-Leu-al). We attempted to transfer this model to mouse studies, where genetics can be more readily investigated due to the availability of genetically modified mice. We treated C57BL/6 (B6) mice with six intraperitoneal injections of 6 mg/kg PSI in 50 mul of 70% ethanol over a 2-week-period. We found significant decreases in nigrostriatal dopamine in PSI-treated mice compared with saline-treated mice. However, we observed similar decreases in the ethanol-treated vehicle control group. Administration of ethanol alone led to significant long-term alterations in dopamine levels. Ethanol significantly eclipses the effects of PSI in the dopamine system, and therefore is a confounding vehicle for this model. PMID:17230468

  15. How helpers help: disentangling ecological confounds from the benefits of cooperative breeding.

    PubMed

    Wright, Jonathan; Russell, Andrew F

    2008-05-01

    Evolutionary explanations for helping in cooperative breeding systems usually require a positive effect of helping on the fitness of the breeders being assisted. However, such helper effects have proven surprisingly difficult to quantify. Cockburn et al. (this issue) apply detailed statistical analyses to long-term field data on the enigmatic superb fairy-wren. They show that it is possible to disentangle the complex web of ecological and evolutionary interactions that confound so many studies. Whilst fairy-wren helpers may not increase nest productivity, they do increase future survival of breeding females. This study points the way for future statistical explorations of long-term data in other cooperative birds and mammals.

  16. Parietal and bi-occipital lobe infarction confounded by ethanol-induced optic neuropathy.

    PubMed

    Tornatore, C W; Townsend, J C; Selvin, G J

    1991-08-01

    A frequent occurrence in geriatric and chronically ill patients is the exhibition of several simultaneously occurring and confounding health problems. This paper reports the case of a 61-year-old-white male who presented with an extensive history of multiple brain infarcts, hemiparesis, personality changes and varied visual complaints. Tests in the neurooptometric work-up for this patient included static automated perimetry, stereoacuity and optokinetic nystagmus evaluation. The results were suggestive of multiple cerebrovascular accidents which included the right and left occipital lobes as well as the right parietal lobe. This clinical picture was complicated by the presence of nutritional or ethanol-induced optic neuropathy. Emphasis was placed on a detailed sequential history of events and a complete neurological and optometric evaluation to ascertain the multiple foci of cortical infarction. Corroboration of clinical findings was obtained by computerized axial tomography (CT scan).

  17. Can Jurors Recognize Missing Control Groups, Confounds, and Experimenter Bias in Psychological Science?

    PubMed Central

    McAuliff, Bradley D.; Kovera, Margaret Bull; Nunez, Gabriel

    2010-01-01

    This study examined the ability of jury-eligible community members (N = 248) to detect internal validity threats in psychological science presented during a trial. Participants read a case summary in which an expert testified about a study that varied in internal validity (valid, missing control group, confound, and experimenter bias) and ecological validity (high, low). Ratings of expert evidence quality and expert credibility were higher for the valid versus missing control group versions only. Internal validity did not influence verdict or ratings of plaintiff credibility and no differences emerged as a function of ecological validity. Expert evidence quality, expert credibility, and plaintiff credibility were positively correlated with verdict. Implications for the scientific reasoning literature and for trials containing psychological science are discussed. PMID:18587635

  18. Temperature: a prolonged confounding factor on cholinesterase activity in the tropical reef fish Acanthochromis polyacanthus.

    PubMed

    Botté, Emmanuelle S; Smith-Keune, Carolyn; Jerry, Dean R

    2013-09-15

    Cholinesterase activity usually decreases in fish exposed to anticholinesterase compounds such as organophosphate and carbamate pesticides. Here we show that tropical reef fish Acanthochromis polyacanthus (or spiny damsel) also exhibits a decrease in ChE activity when exposed to elevated temperature from 28°C to 32°C or 34°C after 4 days. We further demonstrate that the decline persists even after 7 days of recovery at control temperature. This is the first report of a drop in ChE activity in fish as temperature increases. Our results strongly suggest the need for long-term monitoring of water temperature in the field prior to sampling A. polyacanthus for toxicology studies, as temperature is a prolonged and confounding factor for ChE activity in this species.

  19. Missing variables: how exclusion of human resources policy information confounds research connecting health and business outcomes.

    PubMed

    Lynch, Wendy D; Sherman, Bruce W

    2014-01-01

    When corporate health researchers examine the effects of health on business outcomes or the effect of health interventions on health and business outcomes, results will necessarily be confounded by the corporate environment(s) in which they are studied. In this research setting, most studies control for factors traditionally identified in public health, such as demographics and health status. Nevertheless, often overlooked is the extent to which company policies can also independently impact health care cost, work attendance, and productivity outcomes. With changes in employment and benefits practices resulting from health care reform, including incentives and plan design options, consideration of these largely neglected variables in research design has become increasingly important. This commentary summarizes existing knowledge regarding the implications of policy variations in research outcomes and provides a framework for incorporating them into future employer-based research.

  20. Can jurors recognize missing control groups, confounds, and experimenter bias in psychological science?

    PubMed

    McAuliff, Bradley D; Kovera, Margaret Bull; Nunez, Gabriel

    2009-06-01

    This study examined the ability of jury-eligible community members (N = 248) to detect internal validity threats in psychological science presented during a trial. Participants read a case summary in which an expert testified about a study that varied in internal validity (valid, missing control group, confound, and experimenter bias) and ecological validity (high, low). Ratings of expert evidence quality and expert credibility were higher for the valid versus missing control group versions only. Internal validity did not influence verdict or ratings of plaintiff credibility and no differences emerged as a function of ecological validity. Expert evidence quality, expert credibility, and plaintiff credibility were positively correlated with verdict. Implications for the scientific reasoning literature and for trials containing psychological science are discussed.

  1. PERMANOVA-S: association test for microbial community composition that accommodates confounders and multiple distances

    PubMed Central

    Tang, Zheng-Zheng; Chen, Guanhua; Alekseyenko, Alexander V.

    2016-01-01

    Motivation: Recent advances in sequencing technology have made it possible to obtain high-throughput data on the composition of microbial communities and to study the effects of dysbiosis on the human host. Analysis of pairwise intersample distances quantifies the association between the microbiome diversity and covariates of interest (e.g. environmental factors, clinical outcomes, treatment groups). In the design of these analyses, multiple choices for distance metrics are available. Most distance-based methods, however, use a single distance and are underpowered if the distance is poorly chosen. In addition, distance-based tests cannot flexibly handle confounding variables, which can result in excessive false-positive findings. Results: We derive presence-weighted UniFrac to complement the existing UniFrac distances for more powerful detection of the variation in species richness. We develop PERMANOVA-S, a new distance-based method that tests the association of microbiome composition with any covariates of interest. PERMANOVA-S improves the commonly-used Permutation Multivariate Analysis of Variance (PERMANOVA) test by allowing flexible confounder adjustments and ensembling multiple distances. We conducted extensive simulation studies to evaluate the performance of different distances under various patterns of association. Our simulation studies demonstrate that the power of the test relies on how well the selected distance captures the nature of the association. The PERMANOVA-S unified test combines multiple distances and achieves good power regardless of the patterns of the underlying association. We demonstrate the usefulness of our approach by reanalyzing several real microbiome datasets. Availability and Implementation: miProfile software is freely available at https://medschool.vanderbilt.edu/tang-lab/software/miProfile. Contact: z.tang@vanderbilt.edu or g.chen@vanderbilt.edu Supplementary information: Supplementary data are available at Bioinformatics

  2. Measurement confounding affects the extent to which verbal IQ explains social gradients in mortality

    PubMed Central

    Chapman, Benjamin; Fiscella, Kevin; Duberstein, Paul; Kawachi, Ichiro; Muennig, Peter

    2016-01-01

    Background IQ is thought to explain social gradients in mortality. IQ scores are based roughly equally on Verbal IQ (VIQ) and Performance IQ tests. VIQ tests, however, are suspected to confound true verbal ability with socioeconomic status (SES), raising the possibility that associations between SES and IQ scores might be overestimated. We examined, first, whether two of the most common types of VIQ tests exhibited differential item functioning (DIF) favouring persons of higher SES and/or majority race/ethnicity. Second, we assessed what impact, if any, this had on estimates of the extent to which VIQ explains social gradients in mortality. Methods Data from the General Social Survey-National Death Index cohort, a US population representative dataset, was used. Item response theory models queried social-factor DIF on the Thorndike Verbal Intelligence Scale and Wechsler Adult Intelligence Scales, Revised Similarities test. Cox models examined mortality associations among SES and VIQ scores corrected and uncorrected for DIF. Results When uncorrected for DIF, VIQ was correlated with income, education, occupational prestige and race, with correlation coefficients ranging between |0.12| and |0.43|. After correcting for DIF, correlations ranged from |0.06| to |0.16|. Uncorrected VIQ scores explained 11–40% of the Relative Index of Inequalities in mortality for social factors, while DIF-corrected scores explained 2–29%. Conclusions Two of the common forms of VIQ tests appear confound verbal intelligence with SES. Since these tests appear in most IQ batteries, circumspection may be warranted in estimating the amount of social inequalities in mortality attributable to IQ. PMID:24729404

  3. Electronic structure of UO2.12 calculated in the coherent potential approximation taking into account strong electron correlations and spin-orbit coupling

    NASA Astrophysics Data System (ADS)

    Korotin, M. A.; Pchelkina, Z. V.; Skorikov, N. A.; Efremov, A. V.; Anisimov, V. I.

    2016-07-01

    Based on the coherent potential approximation, the method of calculating the electronic structure of nonstoichiometric and hyperstoichiometric compounds with strong electron correlations and spin-orbit coupling has been developed. This method can be used to study both substitutional and interstitial impurities, which is demonstrated based on the example of the hyperstoichiometric UO2.12 compound. The influence of the coherent potential on the electronic structure of compounds has been shown for the nonstoichiometric UO1.87 containing vacancies in the oxygen sublattice as substitutional impurities, for stoichiometric UO2 containing vacancies in the oxygen sublattice and oxygen as an interstitial impurity, and for hyperstoichiometric UO2.12 with excess oxygen also as interstitial impurity. In the model of the uniform distribution of impurities, which forms the basis of the coherent potential approximation, the energy spectrum of UO2.12 has a metal-like character.

  4. Cesarean Section and Subsequent Stillbirth, Is Confounding by Indication Responsible for the Apparent Association? An Updated Cohort Analysis of a Large Perinatal Database

    PubMed Central

    Wood, Stephen; Ross, Sue; Sauve, Reg

    2015-01-01

    Background Several studies and a recent meta-analysis have suggested that previous Cesarean section may increase the risk of stillbirth in a subsequent pregnancy. Given the high rates of Cesarean section in contemporary obstetric practice, this is of considerable public health importance. We sought to evaluate the potential that this association is the result of residual confounding bias. Methods A large perinatal database (Alberta Perinatal Health Project) was searched to identify a matched set of first and second births from the years 1992–2006. Data on pregnancy outcomes, demographics and potential confounding factors were obtained. Results The cohort was comprised of 98538 matched first and second births. Multivariate analysis did not reveal an association between previous Cesarean section and stillbirth, OR = 1.38 (0.98, 1.93). Restricting the analysis to a low risk group further attenuated the association, OR = .99 (0.62, 1.52). Analysis of the risk by indication for Cesarean section found that the risk was not increased for previous dystocia, OR = .91 (0.53, 1.55) nor for breech presentation, OR = 1.06 (0.50, 2.28) but only for other indications including non reassuring fetal status and fetal distress, OR = 1.96 (1.29, 2.98). Conclusions The results of our cohort analysis suggest that previous Cesarean section does not cause an increased risk of stillbirth. PMID:26331274

  5. Selective predation on hantavirus-infected voles by owls and confounding effects from landscape properties.

    PubMed

    Khalil, Hussein; Ecke, Frauke; Evander, Magnus; Hörnfeldt, Birger

    2016-06-01

    It has been suggested that predators may protect human health through reducing disease-host densities or selectively preying on infected individuals from the population. However, this has not been tested empirically. We hypothesized that Tengmalm's owl (Aegolius funereus) selectively preys on hantavirus-infected individuals of its staple prey, the bank vole (Myodes glareolus). Bank voles are hosts of Puumala hantavirus, which causes a form of hemorrhagic fever in humans. Selective predation by owls on infected voles may reduce human disease risk. We compared the prevalence of anti-Puumala hantavirus antibodies (seroprevalence), in bank voles cached by owls in nest boxes to seroprevalence in voles trapped in closed-canopy forest around each nest box. We found no general difference in seroprevalence. Forest landscape structure could partly account for the observed patterns in seroprevalence. Only in more connected forest patches was seroprevalence in bank voles cached in nest boxes higher than seroprevalence in trapped voles. This effect disappeared with increasing forest patch isolation, as seroprevalence in trapped voles increased with forest patch isolation, but did not in cached voles. Our results suggest a complex relationship between zoonotic disease prevalence in hosts, their predators, and landscape structure. Some mechanisms that may have caused the seroprevalence patterns in our results include higher bank vole density in isolated forest patches. This study offers future research potential to shed further light on the contribution of predators and landscape properties to human health. PMID:26873607

  6. Did the No Child Left Behind Act Miss the Mark? Assessing the Potential Benefits from an Accountability System for Early Childhood Education

    ERIC Educational Resources Information Center

    Miller, Lawrence J.; Smith, Stephanie C.

    2011-01-01

    With growing evidence that human capital investment is more efficiently spent on younger children coupled with wide variation in preschool access across states, this article uses a neoliberal approach to examine the potential social costs and benefits that could accrue should the United States decide to implement a centralized preschool…

  7. A comparative account of quantum dynamics of the H⁺ + H₂ reaction at low temperature on two different potential energy surfaces.

    PubMed

    Rajagopala Rao, T; Mahapatra, S; Honvault, P

    2014-08-14

    Rotationally resolved reaction probabilities, integral cross sections, and rate constant for the H(+) + H2 (v = 0, j = 0 or 1) → H2 (v' = 0, j') + H(+) reaction are calculated using a time-independent quantum mechanical method and the potential energy surface of Kamisaka et al. [J. Chem. Phys. 116, 654 (2002)] (say KBNN PES). All partial wave contributions of the total angular momentum, J, are included to obtain converged cross sections at low collision energies and rate constants at low temperatures. In order to test the accuracy of the KBNN PES, the results obtained here are compared with those obtained in our earlier work [P. Honvault et al., Phys. Rev. Lett. 107, 023201 (2011)] using the accurate potential energy surface of Velilla et al. [J. Chem. Phys. 129, 084307 (2008)]. Integral cross sections and rate constants obtained on the two potential energy surfaces considered here show remarkable differences in terms of magnitude and dependence on collision energy (or temperature) which can be attributed to the differences observed in the topography of the surfaces near to the entrance channel. This clearly shows the inadequacy of the KBNN PES for calculations at low collision energies.

  8. A comparative account of quantum dynamics of the H+ + H2 reaction at low temperature on two different potential energy surfaces

    NASA Astrophysics Data System (ADS)

    Rao, T. Rajagopala; Mahapatra, S.; Honvault, P.

    2014-08-01

    Rotationally resolved reaction probabilities, integral cross sections, and rate constant for the H+ + H2 (v = 0, j = 0 or 1) → H2 (v' = 0, j') + H+ reaction are calculated using a time-independent quantum mechanical method and the potential energy surface of Kamisaka et al. [J. Chem. Phys. 116, 654 (2002)] (say KBNN PES). All partial wave contributions of the total angular momentum, J, are included to obtain converged cross sections at low collision energies and rate constants at low temperatures. In order to test the accuracy of the KBNN PES, the results obtained here are compared with those obtained in our earlier work [P. Honvault et al., Phys. Rev. Lett. 107, 023201 (2011)] using the accurate potential energy surface of Velilla et al. [J. Chem. Phys. 129, 084307 (2008)]. Integral cross sections and rate constants obtained on the two potential energy surfaces considered here show remarkable differences in terms of magnitude and dependence on collision energy (or temperature) which can be attributed to the differences observed in the topography of the surfaces near to the entrance channel. This clearly shows the inadequacy of the KBNN PES for calculations at low collision energies.

  9. [The characteristics of the cortical potentials taking into account the high-frequency components in dogs during their instrumental learning studied using nontraditional analytical methods].

    PubMed

    Dumenko, V N; Kozlov, M K

    1994-01-01

    A new method of EEG coding (alternative to classical FFT) was worked up. It allowed to compensate for limitations of FFT and to obtain new information on the shape of EEG curve reflecting peculiarities of oscillations of potentials. Proposed technique of EEG coding seems to be adequate for revealing individual and regional features of EEG and their estimation at different stages of instrumental conditioning. Data obtained using this method confirm the reality of high frequency EEG components of small power. In addition, by the method used the intensification of slow wave EEG components was demonstrated in some cortical regions which could not be revealed by FFT.

  10. With a careful look: still no low-level confound to face pop-out.

    PubMed

    Hershler, Orit; Hochstein, Shaul

    2006-09-01

    In this issue of Vision Research, VanRullen, R. (2006). On second glance: Still no high-level pop-out effect for faces. Vision Research, in press. challenges our earlier Vision Research paper, "At first sight: A high-level pop-out effect for faces" (Hershler, O., & Hochstein, S. (2005). At first sight: A high-level pop-out effect for faces. Vision Research, 45, 1707-1724). In that paper, we showed that faces pop-out from a great variety of heterogeneous distractors. This search must have been based on a holistic combination of facial features, since it could not have relied on any single low-level distinguishing feature-each of which was present in at least some of the distractors. VanRullen implies that the pop-out effect is not limited to faces, is not holistic, and is due to a low-level confound, namely that the "low-level" Fourier amplitude spectrum may differentiate between faces and other categories. We now show that he fails to substantiate all three claims. His first experiment replicates our own and shows once again that faces do indeed pop-out, while other objects, such as cars, do not. The claim regarding the non-holistic nature of face search is based on a failure to differentiate between holistic processing for face detection and for individual face identification. His central claim is that the Fourier amplitude spectrum is processed low-level and could be used for face pop-out. However, changing the amplitude spectrum may well affect high-level representations as well. For example, his demonstration uses hybrid images which are extremely fuzzy, rendering them difficult to identify. More importantly, this claim would lead to the conclusion that targets with a non-face phase spectrum and only a face amplitude spectrum would pop-out among distractors with different amplitude spectra. We demonstrate that this is, of course, not the case and that the Fourier amplitude is not the hoped for "low-level confound". Until another such "hidden" low level feature

  11. Thinking about Accountability

    PubMed Central

    Deber, Raisa B.

    2014-01-01

    Accountability is a key component of healthcare reforms, in Canada and internationally, but there is increasing recognition that one size does not fit all. A more nuanced understanding begins with clarifying what is meant by accountability, including specifying for what, by whom, to whom and how. These papers arise from a Partnership for Health System Improvement (PHSI), funded by the Canadian Institutes of Health Research (CIHR), on approaches to accountability that examined accountability across multiple healthcare subsectors in Ontario. The partnership features collaboration among an interdisciplinary team, working with senior policy makers, to clarify what is known about best practices to achieve accountability under various circumstances. This paper presents our conceptual framework. It examines potential approaches (policy instruments) and postulates that their outcomes may vary by subsector depending upon (a) the policy goals being pursued, (b) governance/ownership structures and relationships and (c) the types of goods and services being delivered, and their production characteristics (e.g., contestability, measurability and complexity). PMID:25305385

  12. Effect of water quality and confounding factors on digestive enzyme activities in Gammarus fossarum.

    PubMed

    Charron, L; Geffard, O; Chaumot, A; Coulaud, R; Queau, H; Geffard, A; Dedourge-Geffard, O

    2013-12-01

    The feeding activity and subsequent assimilation of the products resulting from food digestion allow organisms to obtain energy for growth, maintenance and reproduction. Among these biological parameters, we studied digestive enzymes (amylase, cellulase and trypsin) in Gammarus fossarum to assess the impact of contaminants on their access to energy resources. However, to enable objective assessment of a toxic effect of decreased water quality on an organisms' digestive capacity, it is necessary to establish reference values based on its natural variability as a function of changing biotic and abiotic factors. To limit the confounding influence of biotic factors, a caging approach with calibrated male organisms from the same population was used. This study applied an in situ deployment at 23 sites of the Rhone basin rivers, complemented by a laboratory experiment assessing the influence of two abiotic factors (temperature and conductivity). The results showed a small effect of conductivity on cellulase activity and a significant effect of temperature on digestive enzyme activity but only at the lowest temperature (7 °C). The experimental conditions allowed us to define an environmental reference value for digestive enzyme activities to select sites where the quality of the water impacted the digestive capacity of the organisms. In addition to the feeding rate, this study showed the relevance of digestive enzymes as biomarkers to be used as an early warning tool to reflect organisms' health and the chemical quality of aquatic ecosystems.

  13. Platelets confound the measurement of extracellular miRNA in archived plasma

    PubMed Central

    Mitchell, Adam J.; Gray, Warren D.; Hayek, Salim S.; Ko, Yi-An; Thomas, Sheena; Rooney, Kim; Awad, Mosaab; Roback, John D.; Quyyumi, Arshed; Searles, Charles D.

    2016-01-01

    Extracellular miRNAs are detectable in biofluids and represent a novel class of disease biomarker. Although many studies have utilized archived plasma for miRNA biomarker discovery, the effects of processing and storage have not been rigorously studied. Previous reports have suggested plasma samples are commonly contaminated by platelets, significantly confounding the measurement of extracellular miRNA, which was thought to be easily addressed by additional post-thaw plasma processing. In a case-control study of archived plasma, we noted a significant correlation between miRNA levels and platelet counts despite post-thaw processing. We thus examined the effects of a single freeze/thaw cycle on microparticles (MPs) and miRNA levels, and show that a single freeze/thaw cycle of plasma dramatically increases the number of platelet-derived MPs, contaminates the extracellular miRNA pool, and profoundly affects the levels of miRNAs detected. The measurement of extracellular miRNAs in archived samples is critically dependent on the removal of residual platelets prior to freezing plasma samples. Many previous clinical studies of extracellular miRNA in archived plasma should be interpreted with caution and future studies should avoid the effects of platelet contamination. PMID:27623086

  14. The Scalp Confounds Near-Infrared Signal from Rat Brain Following Innocuous and Noxious Stimulation

    PubMed Central

    He, Ji-Wei; Liu, Hanli; Peng, Yuan Bo

    2015-01-01

    Functional near-infrared imaging (fNIRI) is a non-invasive, low-cost and highly portable technique for assessing brain activity and functions. Both clinical and experimental evidence suggest that fNIRI is able to assess brain activity at associated regions during pain processing, indicating a strong possibility of using fNIRI-derived brain activity pattern as a biomarker for pain. However, it remains unclear how, especially in small animals, the scalp influences fNIRI signal in pain processing. Previously, we have shown that the use of a multi-channel system improves the spatial resolution of fNIRI in rats (without the scalp) during pain processing. Our current work is to investigate a scalp effect by comparing with new data from rats with the scalp during innocuous or noxious stimulation (n = 6). Results showed remarkable stimulus-dependent differences between the no-scalp and intact-scalp groups. In conclusion, the scalp confounded the fNIRI signal in pain processing likely via an autonomic mechanism; the scalp effect should be a critical factor in image reconstruction and data interpretation. PMID:26426058

  15. Reproductive and socioeconomic determinants of child survival: confounded, interactive, and age-dependent effects.

    PubMed

    Kost, K; Amin, S

    1992-01-01

    Studies of infant and child mortality have evolved to distinguish between two sets of explanatory variables-factors related to reproductive or maternal characteristics and socioeconomic factors, generally described as characteristics of the family or household. Almost all multivariate analyses include variables from each of these two sets, but there has been little consideration of the relationship between them. We examine how these two sets of variables jointly affect mortality. We test first for confounded effects by examining socioeconomic effects while excluding and then including reproductive variables in nested multivariate models. Next, we look for age-dependent effects among the explanatory variables and find that reproductive and socioeconomic factors affect mortality at differing ages of children. Finally, we examine interactive effects of the two sets of variables. We conclude that the higher mortality observed among the low status groups is not a result of greater concentration of poor reproductive patterns in those groups. Instead, higher status groups probably have more resources available for combating the negative effects of the same high-risk reproductive patterns. PMID:1514117

  16. Confounding factors and genetic polymorphism in the evaluation of individual steroid profiling

    PubMed Central

    Kuuranne, Tiia; Saugy, Martial; Baume, Norbert

    2014-01-01

    In the fight against doping, steroid profiling is a powerful tool to detect drug misuse with endogenous anabolic androgenic steroids. To establish sensitive and reliable models, the factors influencing profiling should be recognised. We performed an extensive literature review of the multiple factors that could influence the quantitative levels and ratios of endogenous steroids in urine matrix. For a comprehensive and scientific evaluation of the urinary steroid profile, it is necessary to define the target analytes as well as testosterone metabolism. The two main confounding factors, that is, endogenous and exogenous factors, are detailed to show the complex process of quantifying the steroid profile within WADA-accredited laboratories. Technical aspects are also discussed as they could have a significant impact on the steroid profile, and thus the steroid module of the athlete biological passport (ABP). The different factors impacting the major components of the steroid profile must be understood to ensure scientifically sound interpretation through the Bayesian model of the ABP. Not only should the statistical data be considered but also the experts in the field must be consulted for successful implementation of the steroidal module. PMID:24764553

  17. The confounding complexity of innate immune receptors within and between teleost species.

    PubMed

    Wcisel, Dustin J; Yoder, Jeffrey A

    2016-06-01

    Teleost genomes encode multiple multigene families of immunoglobulin domain-containing innate immune receptors (IIIRs) with unknown function and no clear mammalian orthologs. However, the genomic organization of IIIR gene clusters and the structure and signaling motifs of the proteins they encode are similar to those of mammalian innate immune receptor families such as the killer cell immunoglobulin-like receptors (KIRs), leukocyte immunoglobulin-like receptors (LILRs), Fc receptors, triggering receptors expressed on myeloid cells (TREMs) and CD300s. Teleost IIIRs include novel immune-type receptors (NITRs); diverse immunoglobulin domain containing proteins (DICPs); polymeric immunoglobulin receptor-like proteins (PIGRLs); novel immunoglobulin-like transcripts (NILTs) and leukocyte immune-type receptors (LITRs). The accumulation of genomic sequence data has revealed that IIIR gene clusters in zebrafish display haplotypic and gene content variation. This intraspecific genetic variation, as well as significant interspecific variation, frequently confounds the identification of definitive orthologous IIIR sequences between teleost species. Nevertheless, by defining which teleost lineages encode (and do not encode) different IIIR families, predictions can be made about the presence (or absence) of specific IIIR families in each teleost lineage. It is anticipated that further investigations into available genomic resources and the sequencing of a variety of multiple teleost genomes will identify additional IIIR families and permit the modeling of the evolutionary origins of IIIRs. PMID:26997203

  18. Task differences confound sex differences in receiver permissiveness in túngara frogs.

    PubMed

    Bernal, Ximena E; Rand, A Stanley; Ryan, Michael J

    2009-04-01

    In many mating systems, both sexes respond to the same sexual signal. In frogs, males typically call in response to advertisement calls, while females approach male calls in choosing a mate. The costs of signal detection errors are expected to differ between the sexes. Missed opportunities are costly for males because ignoring a signal results in failing to compete with rivals for mates, while their cost for misidentification is lower (time and energy displaying to the incorrect target). By contrast, for females, the cost of misidentification is high (mating with incorrect species or low-quality partner), while their cost for missed opportunity is lower because the operational sex ratio puts females at a premium. Consequently, females should be more selective in their response to signal variation than males. We report that presumed sexual differences in selectivity in túngara frogs (Physalaemus pustulosus) are task-specific rather than sex-specific. As predicted, male túngara frogs are less selective in their vocal responses than are females in their phonotactic responses. Males exhibiting phonotaxis to the same calls, however, are as selective as females, and are significantly more selective than when they respond vocally to the same calls. Our study shows that apparent differences between the sexes emerge from differences in the behaviours themselves and are not intrinsic to each sex. Analogous behavioural differences might confound sex differences in other systems; thus, we suggest consideration of the behavioural plasticity of sex as well as its stereotypy. PMID:19141428

  19. Isolating Cognitive and Neurologic HIV Effects in Substance-Dependent, Confounded Cohorts: A Pilot Study

    PubMed Central

    Byrd, Desiree A.; Robinson-Papp, Jessica; Mindt, Monica Rivera; Mintz, Letty; Elliott, Kathryn; Lighty, Quenesha; Morgello, Susan

    2013-01-01

    Controversy exists as to whether effects of HIV infection can be detected in the cognitive profiles of substance users, with methodological differences in degree of control for confounding factors a major contributor to empirical discrepancies. To address this shortcoming, we conducted a small but well-controlled study aimed at isolating HIV neurocognitive (NC) effects in a group of chronic substance users. Thirty HIV-negative substance users were individually matched to 30 HIV-positive substance users on relevant medical and demographic factors, including reading level and methadone therapy status. Results revealed that reading level, methadone maintenance therapy, and positive urine toxicology each exerted significant influence on NC function, and that HIV status was a significant predictor of learning and speeded processing after these control factors were considered. The HIV-positive group also displayed significantly more neurologically assessed motor impairment (p <.05), which was specifically related to impaired cognition in this group and independent of degree of immunocompromise. These data demonstrate the need for increased attention to clinical/demographic characteristics of groups under study. They also show that with applied methodological rigor, the deleterious effects of HIV on cognition can be parsed from substance use, even in small samples with chronic and active use histories. PMID:23446056

  20. Platelets confound the measurement of extracellular miRNA in archived plasma.

    PubMed

    Mitchell, Adam J; Gray, Warren D; Hayek, Salim S; Ko, Yi-An; Thomas, Sheena; Rooney, Kim; Awad, Mosaab; Roback, John D; Quyyumi, Arshed; Searles, Charles D

    2016-01-01

    Extracellular miRNAs are detectable in biofluids and represent a novel class of disease biomarker. Although many studies have utilized archived plasma for miRNA biomarker discovery, the effects of processing and storage have not been rigorously studied. Previous reports have suggested plasma samples are commonly contaminated by platelets, significantly confounding the measurement of extracellular miRNA, which was thought to be easily addressed by additional post-thaw plasma processing. In a case-control study of archived plasma, we noted a significant correlation between miRNA levels and platelet counts despite post-thaw processing. We thus examined the effects of a single freeze/thaw cycle on microparticles (MPs) and miRNA levels, and show that a single freeze/thaw cycle of plasma dramatically increases the number of platelet-derived MPs, contaminates the extracellular miRNA pool, and profoundly affects the levels of miRNAs detected. The measurement of extracellular miRNAs in archived samples is critically dependent on the removal of residual platelets prior to freezing plasma samples. Many previous clinical studies of extracellular miRNA in archived plasma should be interpreted with caution and future studies should avoid the effects of platelet contamination. PMID:27623086

  1. Metabolic equivalents of task are confounded by adiposity, which disturbs objective measurement of physical activity.

    PubMed

    Tompuri, Tuomo T

    2015-01-01

    Physical activity refers any bodily movements produced by skeletal muscles that expends energy. Hence the amount and the intensity of physical activity can be assessed by energy expenditure. Metabolic equivalents of task (MET) are multiplies of the resting metabolism reflecting metabolic rate during exercise. The standard MET is defined as 3.5 ml/min/kg. However, the expression of energy expenditure by body weight to normalize the size differences between subjects causes analytical hazards: scaling by body weight does not have a physiological, mathematical, or physical rationale. This review demonstrates by examples that false methodology may cause paradoxical observations if physical activity would be assessed by body weight scaled values such as standard METs. While standard METs are confounded by adiposity, lean mass proportional measures of energy expenditure would enable a more truthful choice to assess physical activity. While physical activity as a behavior and cardiorespiratory fitness or adiposity as a state represents major determinants of public health, specific measurements of health determinants must be understood to enable a truthful evaluation of the interactions and their independent role as a health predictor.

  2. Metabolic equivalents of task are confounded by adiposity, which disturbs objective measurement of physical activity

    PubMed Central

    Tompuri, Tuomo T.

    2015-01-01

    Physical activity refers any bodily movements produced by skeletal muscles that expends energy. Hence the amount and the intensity of physical activity can be assessed by energy expenditure. Metabolic equivalents of task (MET) are multiplies of the resting metabolism reflecting metabolic rate during exercise. The standard MET is defined as 3.5 ml/min/kg. However, the expression of energy expenditure by body weight to normalize the size differences between subjects causes analytical hazards: scaling by body weight does not have a physiological, mathematical, or physical rationale. This review demonstrates by examples that false methodology may cause paradoxical observations if physical activity would be assessed by body weight scaled values such as standard METs. While standard METs are confounded by adiposity, lean mass proportional measures of energy expenditure would enable a more truthful choice to assess physical activity. While physical activity as a behavior and cardiorespiratory fitness or adiposity as a state represents major determinants of public health, specific measurements of health determinants must be understood to enable a truthful evaluation of the interactions and their independent role as a health predictor. PMID:26321958

  3. Study by nontraditional analytic methods of features of cortical potentials, taking high-frequency components into account, in dogs during instrumental learning.

    PubMed

    Dumenko, V N; Kozlov, M K

    1995-01-01

    A new method has been developed for the coding of EEG tracings which is an alternative to the classical spectral correlation analysis. This method has made it possible to compensate to a considerable degree for limitations which are unavoidable with the Fourier transform, and to obtain additional information regarding the form of the tracing, which reflects the fluctuations of brain potentials. The new system that has been presented for coding the EEG is, in our view, the most adequate (of the methods known to us) for identifying the individual features of the EEG, in terms of evaluating both their regional differences and similarities. The data obtained convince us once again of the real existence of high-frequency low-power components of the EEG, and their enhancement during instrumental learning in dogs (motor alimentary conditioned reflexes). In addition, data have been obtained pointing to the intensification in some regions of a slow-wave constituent; this has not been observed previously in carrying out a Fourier transform.

  4. Interpretational Confounding Is Due to Misspecification, Not to Type of Indicator: Comment on Howell, Breivik, and Wilcox (2007)

    ERIC Educational Resources Information Center

    Bollen, Kenneth A.

    2007-01-01

    R. D. Howell, E. Breivik, and J. B. Wilcox (2007) have argued that causal (formative) indicators are inherently subject to interpretational confounding. That is, they have argued that using causal (formative) indicators leads the empirical meaning of a latent variable to be other than that assigned to it by a researcher. Their critique of causal…

  5. Marked overlap of four genetic syndromes with dyskeratosis congenita confounds clinical diagnosis

    PubMed Central

    Walne, Amanda J.; Collopy, Laura; Cardoso, Shirleny; Ellison, Alicia; Plagnol, Vincent; Albayrak, Canan; Albayrak, Davut; Kilic, Sara Sebnem; Patıroglu, Turkan; Akar, Haluk; Godfrey, Keith; Carter, Tina; Marafie, Makia; Vora, Ajay; Sundin, Mikael; Vulliamy, Thomas; Tummala, Hemanth; Dokal, Inderjeet

    2016-01-01

    Dyskeratosis congenita is a highly pleotropic genetic disorder. This heterogeneity can lead to difficulties in making an accurate diagnosis and delays in appropriate management. The aim of this study was to determine the underlying genetic basis in patients presenting with features of dyskeratosis congenita and who were negative for mutations in the classical dyskeratosis congenita genes. By whole exome and targeted sequencing, we identified biallelic variants in genes that are not associated with dyskeratosis congenita in 17 individuals from 12 families. Specifically, these were homozygous variants in USB1 (8 families), homozygous missense variants in GRHL2 (2 families) and identical compound heterozygous variants in LIG4 (2 families). All patients had multiple somatic features of dyskeratosis congenita but not the characteristic short telomeres. Our case series shows that biallelic variants in USB1, LIG4 and GRHL2, the genes mutated in poikiloderma with neutropenia, LIG4/Dubowitz syndrome and the recently recognized ectodermal dysplasia/short stature syndrome, respectively, cause features that overlap with dyskeratosis congenita. Strikingly, these genes also overlap in their biological function with the known dyskeratosis congenita genes that are implicated in telomere maintenance and DNA repair pathways. Collectively, these observations demonstrate the marked overlap of dyskeratosis congenita with four other genetic syndromes, confounding accurate diagnosis and subsequent management. This has important implications for establishing a genetic diagnosis when a new patient presents in the clinic. Patients with clinical features of dyskeratosis congenita need to have genetic analysis of USB1, LIG4 and GRHL2 in addition to the classical dyskeratosis congenita genes and telomere length measurements. PMID:27612988

  6. The essence of linkage-based imprinting detection: Comparing power, type 1 error, and the effects of confounders in two different analysis approaches

    PubMed Central

    Greenberg, David A.; Monti, Maria Cristina; Feenstra, Bjarke; Zhang, Junying; Hodge, Susan E.

    2010-01-01

    Summary Background and goal The epigenetic phenomenon of imprinting is critical to understanding disease expression. However, it is hard to detect and can be species- and tissue-specific. One approach is to detect imprinting by taking advantage of linkage information. Although imprinting detection methods exist, the effects of potential confounders, such as heterogeneity, sex-specific penetrance, and differential sex-based ascertainment, have not been explored in depth. In this study we explored possible confounders using two different imprinting detection approaches. Our goal was to understand the essence of how imprinting and linkage interact and to elucidate the underlying issues in existing imprinting detection approaches. Methods One method (PP) models imprinting by maximizing lod scores with respect to parent-specific penetrances. The other method (DRF) approximates imprinting by maximizing two-point lods with respect to differential male-female recombination fractions. We compared power, type 1 error, and confounder effects in these two linkage-based imprinting detection methods using two-point linkage analysis for simplicity. We computer-simulated data, determining power and type 1 error for imprinting detection among datasets with detectable linkage. We generated data with and without imprinting, with and without heterogeneity, and with varying reduced penetrance, family and dataset size. We also examined non-imprinting situations that could mimic imprinting, e.g., sex-specific penetrances, and a scenario requiring a sex-specified affected parent for ascertainment. Results Without heterogeneity, PP had more imprinting-detecting power than DRF. Surprisingly, PP’s power increased when parental affectedness status was ignored, but decreased with heterogeneity. With heterogeneity, type 1 error could increase dramatically for both methods. However, DRF’s power also appeared to increase under heterogeneity, more than could be attributed to the inflated type

  7. Brief Communication: Latent toxoplasmosis and salivary testosterone concentration--important confounding factors in second to fourth digit ratio studies.

    PubMed

    Flegr, Jaroslav; Lindová, Jitka; Pivoñková, Vera; Havlícek, Jan

    2008-12-01

    A sexually dimorphic characteristic, the second to fourth digit ratio (2D:4D ratio), has been shown to reflect the prenatal concentration of sex steroid hormones and to correlate with many personality, physiological, and life history traits. The correlations are usually stronger for the right than the left hand. Most studies have shown that the 2D:4D ratio does not vary with age or postnatal concentration of sex steroid hormones. Recently, a strong association between left hand 2D:4D ratio and infection with a common human parasite Toxoplasma has been reported. We hypothesized that the confounding effect of Toxoplasma infection on left hand 2D:4D ratio could be responsible for the stronger association between different traits and right hand rather than left hand 2D:4D ratio. This confounding effect of toxoplasmosis could also be responsible for the difficulty in finding an association between 2D:4D ratio and age or postnatal steroid hormone concentration. To test this hypothesis, we analyzed the association between sex and age and 2D:4D ratio in a population of 194 female and 106 male students with and without controlling for the confounding variables of Toxoplasma infection and testosterone concentration. Our results showed that the relationship between age and sex and 2D:4D ratio increased sharply when Toxoplasma infection and testosterone concentration were controlled. These results suggest that left hand 2D:4D ratio is more susceptible to postnatal influences and that the confounding factors of Toxoplasma infection, testosterone concentration and possibly also age, should be controlled in future 2D:4D ratio studies. Because of a stronger 2D:4D dimorphism in Toxoplasma-infected than Toxoplasma-free subjects, we predict that 2D:4D ratio dimorphism as well as right hand/left hand 2D:4D ratio dimorphism will be higher in countries with a high prevalence of Toxoplasma infection than in those with a low prevalence.

  8. Distinguishing benign confounding treatment changes from residual prostate cancer on MRI following laser ablation

    NASA Astrophysics Data System (ADS)

    Litjens, G.; Huisman, H.; Elliott, R.; Shih, N.; Feldman, M.; Viswanath, S.; Fütterer, J.; Bomers, J.; Madabhushi, A.

    2014-03-01

    Laser interstitial thermotherapy (LITT) is a relatively new focal therapy technique for the ablation of localized prostate cancer. However, very little is known about the specific effects of LITT within the ablation zone and the surrounding normal tissue regions. For instance, it is important to be able to assess the extent of residual cancer within the prostate following LITT, which may be masked by thermally induced benign necrotic changes. Fortunately LITT is MRI compatible and hence this allows for quantitatively assessing LITT induced changes via multi-parametric MRI. Of course definite validation of any LITT induced changes on MRI requires confirmation via histopathology. The aim of this study was to quantitatively assess and distinguish the imaging characteristics of prostate cancer and benign confounding treatment changes following LITTon 3 Tesla multi-parametric MRI by carefully mapping the treatment related changes from the ex vivo surgically resected histopathologic specimens onto the pre-operative in vivo imaging. A better understanding of the imaging characteristics of residual disease and successfully ablated tissue might lead to improved treatment monitoring and as such patient prognosis. A unique clinical trial at the Radboud University Medical Center, in which 3 patients underwent a prostatectomy after LITT treatment, yielded ex-vivo histopathologic specimens along with pre- and post-LITT MRI. Using this data we (1) identified the computer extracted MRI signatures associated with treatment effects including benign necrotic changes and residual disease and (2) subsequently evaluated the computer extracted MRI features previously identified in distinguishing LITT induced changes in the ablated area relative to the residual disease. Towards this end first a pathologist annotated the ablated area and the residual disease on the ex-vivo histology and then we transferred the annotations to the post-LITT MRI using semi-automatic elastic registration. The

  9. Blowfly strike in sheep flocks as an example of the use of a time-space scan statistic to control confounding.

    PubMed

    Ward, M P

    2001-04-13

    The use of a time-space scan statistic--defined by a cylindrical window with a circular geographic base and height corresponding to time--was investigated as a method of detecting clustering in veterinary epidemiology whilst controlling confounding. The example data set consisted of farmer-recorded occurrence of body strike and breech strike between August 1998 and May 1999 in 26 sheep flocks located in two local government areas of southeastern Queensland, Australia. This information was derived from a questionnaire survey mailed to farmers. Potentially confounding factors included in the investigation were flock size (< or = median, > median), flock structure (proportion of lambs, wethers, ewes and rams), pesticide application for flystrike control (yes, no) and rainfall (< or = median, > median). The total sheep population within selected flocks was 92,660; 1012 (1.09%) and 518 (0.56%) cases of body strike and breech strike were reported in 16 and 10 flocks, respectively.Clustering analyses of body strike and breech strike were undertaken separately, because different predisposing factors are associated with these diseases. Significant clustering of body strike (28.76 degrees S, 151.82 degrees E) during March 1999 and breech strike (28.73 degrees S, 151.16 degrees E) between February and May 1999 was detected. Adjusting for flock structure, flock size, pesticide use and rainfall did not alter the most likely cluster of body strike identified--although the relative risk changed (> 10%) after adjusting for flock structure. Adjustment for flock structure and rainfall resulted in different clusters of breech strike being identified.

  10. Examining the Relationship between Heavy Alcohol Use and Assaults: With Adjustment for the Effects of Unmeasured Confounders

    PubMed Central

    Liang, Wenbin; Chikritzhs, Tanya

    2015-01-01

    Background. Experimental studies suggest that alcohol can lead to aggression in laboratory settings; however, it is impossible to test the causal relationship between alcohol use and real-life violence among humans in randomized clinical trials. Objectives. (i) To examine the relationship between heavy alcohol use and assaults in a population based study; (ii) to demonstrate the proxy outcome method, as a means of controlling the effects of unknown/unmeasured confounders in observational studies. Methods. This study used data collected from three waves of the National Survey on Drug Use and Health (NSDUH). The effects of heavy alcohol use on assault were measured using multivariable logistic regressions in conjunction with the proxy outcome method. Results. Application of the proxy outcome method indicated that effect sizes of heavy alcohol use on the risk of assault were overestimated in the standard models. After adjusting for the effects of unknown/unmeasured confounders, the risk of assault remained 43% and 63% higher (P < 0.05) among participants who consumed 5+ drinks/day for 5–8 days/month and 9–30 days/month, respectively. Conclusions. Even after adjustment for unknown/unmeasured confounders the association between heavy alcohol use and risk of violence remained significant. These findings support the hypothesis that heavy alcohol use can cause violence. PMID:26380283

  11. Confounding by indication in non-experimental evaluation of vaccine effectiveness: the example of prevention of influenza complications

    PubMed Central

    Hak, E; Verheij, T.; Grobbee, D; Nichol, K; Hoes, A

    2002-01-01

    Randomised allocation of vaccine or placebo is the preferred method to assess the effects of the vaccine on clinical outcomes relevant to the individual patient. In the absence of phase 3 trials using clinical end points, notably post-influenza complications, alternative non-experimental designs to evaluate vaccine effects or safety are often used. The application of these designs may, however, lead to invalid estimates of vaccine effectiveness or safety. As patients with poor prognosis are more likely to be immunised, selection for vaccination is confounded by patient factors that are also related to clinical end points. This paper describes several design and analytical methods aimed at limiting or preventing this confounding by indication in non-experimental studies. In short, comparison of study groups with similar prognosis, restriction of the study population, and statistical adjustment for dissimilarities in prognosis are important tools and should be considered. Only if the investigator is able to show that confounding by indication is sufficiently controlled for, results of a non-experimental study may be of use to direct an evidence based vaccine policy. PMID:12461118

  12. International Accounting and the Accounting Educator.

    ERIC Educational Resources Information Center

    Laribee, Stephen F.

    The American Assembly of Collegiate Schools of Business (AACSB) has been instrumental in internationalizing the accounting curriculum by means of accreditation requirements and standards. Colleges and universities have met the AACSB requirements either by providing separate international accounting courses or by integrating international topics…

  13. Innovations in an Accounting Information Systems Course.

    ERIC Educational Resources Information Center

    Shaoul, Jean

    A new approach to teaching an introductory accounting information systems course is outlined and the potential of this approach for integrating computers into the accounting curriculum at Manchester University (England) is demonstrated. Specifically, the use of a small inventory recording system and database in an accounting information course is…

  14. Meta-analysis of lung cancer in asphalt roofing and paving workers with external adjustment for confounding by coal tar

    SciTech Connect

    Fayerweather, W.E.

    2007-07-01

    The study's objectives were to update Partanen's and Boffetta's 1994 meta-analysis of lung cancer among roofing and paving asphalt workers and explore the role of coal tar in explaining the statistical heterogeneity among these studies. Information retrieval strategies and eligibility criteria were defined for identifying the epidemiologic studies to be included in the analysis. The relative risk ratio (RR) for lung cancer was selected as the effect measure of interest. Coal tar bias factors were developed and used to externally adjust each eligible study's published RR for confounding by coal tar. The meta-Relative Risk (meta-RR) and its variance were estimated by general variance-based methods. Heterogeneity of the RRs was assessed by heterogeneity chi-square and I{sup 2} tests. The results from this update were similar to those in Partanen's and Boffetta's original meta-analysis. Although the meta-RRs for the roofers and the pavers were no longer statistically significantly different from one another, significant heterogeneity remained within each of the coal tar-adjusted sectors. Meta-analysis of non-experimental epidemiologic studies is subject to significant uncertainties as is externally correcting studies for confounding. Given these uncertainties, the specific quantitative estimates in this (or any similar) analysis must be viewed with caution. Nevertheless, this analysis provides support for the hypothesis proposed by several major reviewers that confounding by coal tar-related PAH exposures may explain most or all of the lung cancer risks found in the epidemiologic literature on asphalt roofing and paving workers.

  15. Smoking and degree of occupational exposure: are internal analyses in cohort studies likely to be confounded by smoking status

    SciTech Connect

    Siemiatycki, J.; Wacholder, S.; Dewar, R.; Wald, L.; Begin, D.; Richardson, L.; Rosenman, K.; Gerin, M.

    1988-01-01

    Occupational cohort studies are usually carried out without the benefit of information on smoking habits of cohort members. One common approach to avoid confounding bias related to smoking habits is to carry out an internal analysis, comparing workers with different degrees of occupational exposure. The premise behind this approach is that within a cohort there is unlikely to be correlation between degree of exposure and smoking habits. If this were untrue, smoking could confound the disease-exposure relationships. Our purpose was to verify the premise. The study sample consisted of 857 French-Canadian men born between 1910 and 1930, with 11 or fewer years of education, and interviewed around 1980 in the context of an occupational cancer case-control study. For each man we had information on smoking habits, job history, and a history of the chemicals he was exposed to in each of his jobs. We computed two indices of the dirtiness of workers' job histories: one based on the job titles held by the man and a second based on the degree of exposures to workplace substances. There was no correlation between these indices of job dirtiness and smoking history. We also examined the smoking-exposure relationship among the subsets of men who had been occupationally exposed to ten especially noticeable substances. Within the subsets, there was no indication of a consistent difference among the smoking subgroups in level or duration of exposure to these index substances. These findings do not support the view that nonsmokers sought out cleaner job environments than smokers; they imply that internal analyses of dose-response in cohort studies are unlikely to be seriously confounded by smoking habits.

  16. Gender differences in CNV burden do not confound schizophrenia CNV associations

    PubMed Central

    Han, Jun; Walters, James T. R.; Kirov, George; Pocklington, Andrew; Escott-Price, Valentina; Owen, Michael J.; Holmans, Peter; O’Donovan, Michael C.; Rees, Elliott

    2016-01-01

    Compared with the general population, an excess of rare copy number variants (CNVs) has been identified in people with schizophrenia. Females with neurodevelopmental disorders and in the general population have been reported to carry more large, rare CNVs than males. Given that many schizophrenia datasets do not have equal gender ratios in cases and controls, sex differences in CNV burden might have impacted on estimates of case-related CNV burden and also on associations to individual loci. In a sample of 13,276 cases and 17,863 controls, we observed a small but significant excess of large (≥500 Kb), rare (<1%) CNVs in females compared with males in both cases and controls (OR = 1.17, P = 0.0012 for controls; OR = 1.11, P = 0.045 for cases). The burden of 11 schizophrenia-associated CNVs was significantly higher in female cases compared with male cases (OR = 1.38, P = 0.0055), but after accounting for the rates of CNVs in controls, we found no significant gender difference in the risk conferred by these loci. Controlling for gender had a negligible effect on the significance of association between specific CNVs and schizophrenia. The female excess of large CNVs in both cases and controls suggests a female protective mechanism exists for deleterious CNVs that may extend beyond neurodevelopmental phenotypes. PMID:27185616

  17. Learning bundles of stimuli renders stimulus order as a cue, not a confound.

    PubMed

    Qian, Ting; Aslin, Richard N

    2014-10-01

    The order in which stimuli are presented in an experiment has long been recognized to influence behavior. Previous accounts have often attributed the effect of stimulus order to the mechanisms with which people process information. We propose that stimulus order influences cognition because it is an important cue for learning the underlying structure of a task environment. In particular, stimulus order can be used to infer a "stimulus bundle"--a sequence of consecutive stimuli that share the same underlying latent cluster. We describe a clustering model that successfully explains the perception of streak shooting in basketball games, along with two other cognitive phenomena, as the outcome of finding the statistically optimal bundle representation. We argue that the perspective of viewing stimulus order as a cue may hold the key to explaining behaviors that seemingly deviate from normative theories of cognition and that in task domains where the assumption of stimulus bundles is intuitively appropriate, it can improve the explanatory power of existing models.

  18. [Time-dependent confounding in the estimation of treatment effects in randomised trials with multimodal therapies--an illustration of the problem of time-dependent confounding by causal graphs].

    PubMed

    Zietemann, V D; Schuster, T; Duell, T H G

    2015-01-01

    Biased effect estimates induced by unconsidered confounding variables are a known problem in observational studies. Selection bias, resulting from non-random sampling of study participants, is widely recognised as a problem in case-control and cross-sectional studies. In contrast, possible bias in randomised controlled trials (RCTs) is mostly ignored. This paper illustrates, by applying directed acyclic graphs (DAGs), possible bias in the effect estimates of first-line therapy, caused by subsequent changes in therapy (time-dependent confounding). Possible selection bias, induced by not only random loss to follow-up, will be explained as well using DAGs. Underlying assumptions of standard methods usually used to analyse RCTs (like intention-to-treat, per-protocol) are shown and it is explained why effect estimates may be biased in RCTs, if only these conventional methods are used. Adequate statistical methods (causal inference models as marginal structural models and structural nested models) exist. Higher documentary efforts, however, are necessary, because any changes in medication, loss to follow-up as well as reasons for such changes need to be documented in detail as required by these advanced statistical methods. Nevertheless, causal inference models should become standard along side the currently applied standard methods, especially in studies with high non-compliance due to changes in therapy and substantial loss to follow-up. Possible bias cannot be excluded if similar results are obtained from both methods. However, study results should be interpreted with caution if they differ between both approaches.

  19. HIV infection in the etiology of lung cancer: confounding, causality, and consequences.

    PubMed

    Kirk, Gregory D; Merlo, Christian A

    2011-06-01

    Persons infected with HIV have an elevated risk of lung cancer, but whether the increase simply reflects a higher smoking prevalence continues to be debated. This review summarizes existing data on the association of HIV infection and lung cancer, with particular attention to study design and adjustment for cigarette smoking. Potential mechanisms by which HIV infection may lead to lung cancer are discussed. Finally, irrespective of causality and mechanisms, lung cancer represents an important and growing problem confronting HIV-infected patients and their providers. Substantial efforts are needed to promote smoking cessation and to control lung cancer among HIV-infected populations.

  20. High Levels of Sample-to-Sample Variation Confound Data Analysis for Non-Invasive Prenatal Screening of Fetal Microdeletions.

    PubMed

    Chu, Tianjiao; Yeniterzi, Suveyda; Yatsenko, Svetlana A; Dunkel, Mary; Shaw, Patricia A; Bunce, Kimberly D; Peters, David G

    2016-01-01

    Our goal was to test the hypothesis that inter-individual genomic copy number variation in control samples is a confounding factor in the non-invasive prenatal detection of fetal microdeletions via the sequence-based analysis of maternal plasma DNA. The database of genomic variants (DGV) was used to determine the "Genomic Variants Frequency" (GVF) for each 50kb region in the human genome. Whole genome sequencing of fifteen karyotypically normal maternal plasma and six CVS DNA controls samples was performed. The coefficient of variation of relative read counts (cv.RTC) for these samples was determined for each 50kb region. Maternal plasma from two pregnancies affected with a chromosome 5p microdeletion was also sequenced, and analyzed using the GCREM algorithm. We found strong correlation between high variance in read counts and GVF amongst controls. Consequently we were unable to confirm the presence of the microdeletion via sequencing of maternal plasma samples obtained from two sequential affected pregnancies. Caution should be exercised when performing NIPT for microdeletions. It is vital to develop our understanding of the factors that impact the sensitivity and specificity of these approaches. In particular, benign copy number variation amongst controls is a major confounder, and their effects should be corrected bioinformatically. PMID:27249650

  1. High Levels of Sample-to-Sample Variation Confound Data Analysis for Non-Invasive Prenatal Screening of Fetal Microdeletions

    PubMed Central

    Chu, Tianjiao; Yeniterzi, Suveyda; Yatsenko, Svetlana A.; Dunkel, Mary; Shaw, Patricia A.; Bunce, Kimberly D.; Peters, David G.

    2016-01-01

    Our goal was to test the hypothesis that inter-individual genomic copy number variation in control samples is a confounding factor in the non-invasive prenatal detection of fetal microdeletions via the sequence-based analysis of maternal plasma DNA. The database of genomic variants (DGV) was used to determine the “Genomic Variants Frequency” (GVF) for each 50kb region in the human genome. Whole genome sequencing of fifteen karyotypically normal maternal plasma and six CVS DNA controls samples was performed. The coefficient of variation of relative read counts (cv.RTC) for these samples was determined for each 50kb region. Maternal plasma from two pregnancies affected with a chromosome 5p microdeletion was also sequenced, and analyzed using the GCREM algorithm. We found strong correlation between high variance in read counts and GVF amongst controls. Consequently we were unable to confirm the presence of the microdeletion via sequencing of maternal plasma samples obtained from two sequential affected pregnancies. Caution should be exercised when performing NIPT for microdeletions. It is vital to develop our understanding of the factors that impact the sensitivity and specificity of these approaches. In particular, benign copy number variation amongst controls is a major confounder, and their effects should be corrected bioinformatically. PMID:27249650

  2. Negotiations and Accountability

    ERIC Educational Resources Information Center

    Hough, Charles R.

    1971-01-01

    School boards by state statutes are alone accountable for the education of their communities' youth. What's needed, the writer contends, is a rectification of the statutes so that all parties to negotiations are accountable. (Editor)

  3. LMAL Accounting Office 1936

    NASA Technical Reports Server (NTRS)

    1936-01-01

    Accounting Office: The Langley Memorial Aeronautical Laboratory's accounting office, 1936, with photographs of the Wright brothers on the wall. Although the Lab was named after Samuel P. Langley, most of the NACA staff held the Wrights as their heroes.

  4. Adaption of the LUCI framework to account for detailed farm management: a case study exploring potential for achieving locally and nationally significant greenhouse gas, flooding and nutrient mitigation without compromising livelihoods on New Zealand farm

    NASA Astrophysics Data System (ADS)

    Jackson, Bethanna; Trodahl, Martha; Maxwell, Deborah; Easton, Stuart

    2016-04-01

    This talk discusses recent progress in adapting the Land Utilisation and Capability Indicator (LUCI) framework to take account of the impact of detailed farm management on greenhouse gas emissions and on water, sediment and nutrient delivery to waterways. LUCI is a land management decision support framework which examines the impact of current and potential interventions on a variety of outcomes, including flood mitigation, water supply, greenhouse gas emissions, biodiversity, erosion, sediment and nutrient delivery to waterways, and agricultural production. The potential of the landscape to provide benefits is a function of both the biophysical properties of individual landscape elements and their configuration. Both are respected in LUCI where possible. For example, the hydrology, sediment and chemical routing algorithms are based on physical principles of hillslope flow, taking information on the storage and permeability capacity of elements within the landscape from soil and land use data and honoring physical thresholds, mass and energy balance constraints. LUCI discretizes hydrological response units within the landscape according to similarity of their hydraulic properties and preserves spatially explicit topographical routing. Implications of keeping the "status quo" or potential scenarios of land management change can then be evaluated under different meteorological or climatic events (e.g. flood return periods, rainfall events, droughts), cascading water through the hydrological response units using a "fill and spill" approach. These and other component algorithms are designed to be fast-running while maintaining physical consistency and fine spatial detail. This allows it to operate from subfield level scale to catchment, or even national scale, simultaneously. It analyses and communicates the spatial pattern of individual provision and tradeoffs/synergies between desired outcomes at detailed resolutions and provides suggestions on where management

  5. Managerial Accounting. Study Guide.

    ERIC Educational Resources Information Center

    Plachta, Leonard E.

    This self-instructional study guide is part of the materials for a college-level programmed course in managerial accounting. The study guide is intended for use by students in conjuction with a separate textbook, Horngren's "Accounting for Management Control: An Introduction," and a workbook, Curry's "Student Guide to Accounting for Management…

  6. Accounting & Computing Curriculum Guide.

    ERIC Educational Resources Information Center

    Avani, Nathan T.; And Others

    This curriculum guide consists of materials for use in teaching a competency-based accounting and computing course that is designed to prepare students for employability in the following occupational areas: inventory control clerk, invoice clerk, payroll clerk, traffic clerk, general ledger bookkeeper, accounting clerk, account information clerk,…

  7. Accounting Education in Crisis

    ERIC Educational Resources Information Center

    Turner, Karen F.; Reed, Ronald O.; Greiman, Janel

    2011-01-01

    Almost on a daily basis new accounting rules and laws are put into use, creating information that must be known and learned by the accounting faculty and then introduced to and understood by the accounting student. Even with the 150 hours of education now required for CPA licensure, it is impossible to teach and learn all there is to learn. Over…

  8. The Accounting Capstone Problem

    ERIC Educational Resources Information Center

    Elrod, Henry; Norris, J. T.

    2012-01-01

    Capstone courses in accounting programs bring students experiences integrating across the curriculum (University of Washington, 2005) and offer unique (Sanyal, 2003) and transformative experiences (Sill, Harward, & Cooper, 2009). Students take many accounting courses without preparing complete sets of financial statements. Accountants not only…

  9. From confounders to suspected risk factors: psychosocial factors and work-related upper extremity disorders.

    PubMed

    Feuerstein, Michael; Shaw, William S; Nicholas, Rena A; Huang, Grant D

    2004-02-01

    Psychosocial variables have recently been more prominent among epidemiologic risk factors for work-related upper extremity disorders (WRUEDs), but bio-behavioral mechanisms underlying these associations have been elusive. One reason is that the psychosocial domain has included many broad and disparate variables (e.g. mood, coping skills, job control, job satisfaction, job stress, social support), and this lack of specificity in the conceptualization of psychosocial factors has produced limited hypothesis testing opportunities. Therefore, recent research efforts have focused on identifying and conceptualizing specific psychosocial factors that might more clearly delineate plausible bio-behavioral mechanisms linking psychosocial factors to WRUEDs. One such factor is workstyle, a strategy that workers may employ for completing, responding to, or coping with job demands that might affect musculoskeletal health. Preliminary studies have provided support for measurable differences in workstyle among individual workers and an association with upper extremity pain and discomfort. An initial self-report measure of workstyle has been pilot tested among office workers and shown acceptable reliability and validity. Future studies are needed to study this construct among other working populations and to determine its relationship with other clinical endpoints. Nevertheless, early findings suggest workstyle may be a potential focus of WRUED prevention efforts. PMID:14759762

  10. Prawns, barnacles, and nonsteroidal anti-inflammatory drugs: effect modifiers or diagnostic confounders [corrected].

    PubMed

    Vidal, C; Bartolomé, B; González-Quintela, A; Rodríguez, V; Armisén, M

    2007-01-01

    A 42-year-old woman with no history of atopy reported several episodes of generalized urticaria and shortness of breath after eating shellfish (prawns and barnacles) but with good tolerance of the same foods between episodes. Skin prick tests (SPTs), serum enzyme allergosorbent tests (EAST) for specific immunoglobulin (Ig) E, Western blot and inhibition assays, and oral challenge tests with prawns, barnacles, nonsteroidal anti-inflammatory drugs (NSAIDs), and alcohol as potential effect modifiers were performed. Specific IgE to both barnacle and prawn were detected by SPTs and EAST. Results from a Western blot of raw prawn revealed an IgE binding band of 37 kDa and IgE binding bands of 143, 83, 38, 32, and 20 kDa appeared in the raw barnacle assay. Oral challenge tests were positive with prawns and prawn extract only if preceded by NSAIDs. Oral challenges with NSAIDs alone, prawns alone, barnacles with or without NSAIDs and alcohol led to no reaction. A synergistic effect of NSAIDs in inducing anaphylaxis after prawn intake was confirmed. No similar effect was achieved with barnacles despite the presence of specific IgE. Additional factors needed to elicit a clinical reaction in food allergy may not be obvious and several oral challenge protocols are mandatory in such cases.

  11. Extracellular vesicles in the circulation: are erythrocyte microvesicles a confounder in the plasma haemoglobin assay?

    PubMed

    de Vooght, Karen M K; Lau, Cedric; de Laat, Pim P M; van Wijk, Richard; van Solinge, Wouter W; Schiffelers, Raymond M

    2013-02-01

    Blood contains a mixture of extracellular vesicles from different cell types, primarily platelets, endothelial cells, leucocytes and erythrocytes. Erythrocytes are the most abundant cell type in blood and could, especially in certain pathologies, represent an important source of vesicles. Since erythrocytes contain the haemoglobin components iron and haem, which are potentially toxic, it is important to investigate the contribution of vesicle-associated haemoglobin to total cell-free haemoglobin levels. To our knowledge, this is the first time that cell-free plasma haemoglobin has been differentiated into vesicle-associated and molecular species. We investigated the contribution of vesicle-associated haemoglobin in residual patient material that was routinely analysed for total cell-free plasma haemoglobin. All patient samples included in the study were haemolytic with total cell-free haemoglobin concentration ranging from 80 to 2500 mg/l. In the majority of the samples, total cell-free haemoglobin concentration was between 100 and 200 mg/l. No haemoglobin could be detected in the vesicle fraction, indicating that the contribution of vesicle-associated haemoglobin to total cell free-haemoglobin levels in plasma is negligible. It is important to investigate whether erythrocyte vesicles are not formed in blood or that their production is not increased during pathologies associated with haemolysis or that the clearance rate of the vesicles surpasses the formation rate.

  12. Accountable Care Organizations and Otolaryngology

    PubMed Central

    Contrera, Kevin J.; Ishii, Lisa E.; Setzen, Gavin; Berkowitz, Scott A.

    2016-01-01

    Accountable Care Organizations represent a shift in health care delivery, while providing a significant potential for improved quality and coordination of care across multiple settings. Otolaryngologists have an opportunity to become leaders in this expanding arena. However, the field of otolaryngology-head and neck surgery currently lacks many of the tools necessary to implement value-based care, including performance-measurement, electronic health infrastructure and data management. These resources will become increasingly important for surgical specialists to be active participants in population health. This article reviews the fundamental issues that otolaryngologists should consider when pursuing new roles in Accountable Care Organizations. PMID:26044787

  13. Disentangling the confounding effects of PAR and air temperature on net ecosystem exchange in time and scale

    NASA Astrophysics Data System (ADS)

    yang, Z.; Chen, J.; Becker, R.; Chu, H.; Xie, J.; Shao, C.

    2013-12-01

    Net ecosystem exchange of CO2 (NEE) in temperate forests is modulated by microclimatic factors. The effects of those factors differ at different time scales and during different time periods. Some of them are correlated across a number of time scales, so their effects on NEE are confounded by each other. PAR and air temperature (Ta) are among the two most important drivers of NEE in temperate forests, and among the two most correlated microclimatic factors. PAR and Ta have similar daily, seasonal, and annual cycles. Their influence on NEE is confounded by each other and entangled together especially at those scales. In this study, we tried to disentangle the confounding effects of them on NEE at different time scales and during different time periods. To accomplish this objective, we applied the innovative spectral analysis techniques including Continuous Wavelet Transformation (CWT), Cross Wavelet Transformation (XWT), Wavelet Coherent (WTC), and Partial Wavelet Coherence (PWC) on seven years time series (2004-2010) of PAR, Ta and NEE from the Ohio Oak Openings site (N 41.5545°, W 83.8438°), USA for spectral analysis. We found that PAR is the major driver at short time scales (e.g. semidiurnal and daily) and Ta is the major driver at long time scales (e.g. seasonal and annual). At daily scale during growing seasons, PAR is anti-phase with NEE with no time delay while Ta lagged PAR about 2-3 hours, which could be explained by the strong dependence of photosynthesis on PAR and a 2-3 hours lags of the daily course of Ta to PAR. At daily scale during non-growing season, NEE has little variation and thus neither Ta nor PAR has high common wavelet power and significant coherence with NEE. At annual scale, Ta is anti-phase with NEE and PAR leads NEE about 34 days, which could be explained by the strong dependence of LAI dynamics on Ta and the lag between the LAI/biomass development and the progress of sunlight. We also found that NEE distributes most of its variation

  14. Soil acidification as a confounding factor on metal phytotoxicity in soils spiked with copper-rich mine wastes.

    PubMed

    Ginocchio, Rosanna; De la Fuente, Luz María; Sánchez, Pablo; Bustamante, Elena; Silva, Yasna; Urrestarazu, Paola; Rodríguez, Patricio H

    2009-10-01

    Pollution of soil with mine wastes results in both Cu enrichment and soil acidification. This confounding effect may be very important in terms of phytotoxicity, because pH is a key parameter influencing Cu solubility in soil solution. Laboratory toxicity tests were used to assess the effect of acidification by acidic mine wastes on Cu solubility and on root elongation of barley (Hordeum vulgare L.). Three contrasting substrates (two soils and a commercial sand) and two acidic, Cu-rich mine wastes (oxidized tailings [OxT] and smelter dust [SmD]) were selected as experimental materials. Substrates were spiked with a fixed amount of either SmD or OxT, and the pH of experimental mixtures was then modified in the range of 4.0 to 6.0 and 7.0 using PIPES (piperazine-1,4-bis(2-ethanesulfonic acid)), MES (2-(N-morpholino)ethanesulfonic acid), and MOPS (3-(N-Morpholino)-propanesulfonic acid) buffers. Chemical (pore-water Cu and pH) and toxicological (root length of barley plants) parameters were determined for experimental mixtures. Addition of SmD and OxT to substrates resulted in acidification (0.11-1.16 pH units) and high levels of soluble Cu and Zn. Neutralization of experimental mixtures with MES (pH 6.0) and MOPS (pH 7.0) buffers resulted in a marked decrease in soluble Cu and Zn, but the intensity of the effect was substrate-dependent. Adjustment of soil pH above the range normally considered to be toxic to plants (pH in water extract, > 5.5) significantly reduced metal toxicity in barley, but phytotoxicity was not completely eliminated. The present results stress the importance of considering confounding effects on derivation of toxicity thresholds to plants when using laboratory phytotoxicity tests. PMID:19480535

  15. When can we measure stress noninvasively? Postdeposition effects on a fecal stress metric confound a multiregional assessment.

    PubMed

    Wilkening, Jennifer L; Ray, Chris; Varner, Johanna

    2016-01-01

    Measurement of stress hormone metabolites in fecal samples has become a common method to assess physiological stress in wildlife populations. Glucocorticoid metabolite (GCM) measurements can be collected noninvasively, and studies relating this stress metric to anthropogenic disturbance are increasing. However, environmental characteristics (e.g., temperature) can alter measured GCM concentration when fecal samples cannot be collected immediately after defecation. This effect can confound efforts to separate environmental factors causing predeposition physiological stress in an individual from those acting on a fecal sample postdeposition. We used fecal samples from American pikas (Ochotona princeps) to examine the influence of environmental conditions on GCM concentration by (1) comparing GCM concentration measured in freshly collected control samples to those placed in natural habitats for timed exposure, and (2) relating GCM concentration in samples collected noninvasively throughout the western United States to local environmental characteristics measured before and after deposition. Our timed-exposure trials clarified the spatial scale at which exposure to environmental factors postdeposition influences GCM concentration in pika feces. Also, fecal samples collected from occupied pika habitats throughout the species' range revealed significant relationships between GCM and metrics of climate during the postdeposition period (maximum temperature, minimum temperature, and precipitation during the month of sample collection). Conversely, we found no such relationships between GCM and metrics of climate during the predeposition period (prior to the month of sample collection). Together, these results indicate that noninvasive measurement of physiological stress in pikas across the western US may be confounded by climatic conditions in the postdeposition environment when samples cannot be collected immediately after defecation. Our results reiterate the importance

  16. Emerging accounting trends accounting for leases.

    PubMed

    Valletta, Robert; Huggins, Brian

    2010-12-01

    A new model for lease accounting can have a significant impact on hospitals and healthcare organizations. The new approach proposes a "right-of-use" model that involves complex estimates and significant administrative burden. Hospitals and health systems that draw heavily on lease arrangements should start preparing for the new approach now even though guidance and a final rule are not expected until mid-2011. This article highlights a number of considerations from the lessee point of view.

  17. Interpretation: a confounding factor.

    PubMed

    Gupta, Mohit

    2016-01-01

    With reference to the article "Passive euthanasia in India: a critique", authored by Ms Rohini Shukla and published online on August 5, 2015, I would like to make a few comments and highlight the following points. First, the author notes that Section 309 IPC has been decriminalised. This is not so since there has neither been any amendment to the IPC, nor has any ordinance been passed regarding the matter. Attempting suicide is still an offence in India. Second, the author observes that withholding life support is an act of omission and withdrawing life support is an act of commission and the terms have been used interchangeably by the Hon'ble Court, although there is a subtle difference between the two terms.

  18. Reactive Aggression and Peer Victimization from Pre-Kindergarten to First Grade: Accounting for Hyperactivity and Teacher-Child Conflict

    ERIC Educational Resources Information Center

    Runions, Kevin C.

    2014-01-01

    Background: The role of reactive aggression in the development of peer victimization remains unclear due in part to a failure to account for confounding problems of behavioural undercontrol (e.g., hyperactivity). As well, the school social context has rarely been examined to see whether these risks are mediated by relationships with teachers.…

  19. Public Accountancy Handbook.

    ERIC Educational Resources Information Center

    New York State Education Dept., Albany. Office of the Professions.

    A reference guide to laws, rules, and regulations that govern public accountancy practice in New York State is presented. In addition to identifying licensing requirements/procedures for certified public accountants, general provisions of Title VIII of the Education Law are covered, along with state management, professional misconduct, and…

  20. PLATO IV Accountancy Index.

    ERIC Educational Resources Information Center

    Pondy, Dorothy, Comp.

    The catalog was compiled to assist instructors in planning community college and university curricula using the 48 computer-assisted accountancy lessons available on PLATO IV (Programmed Logic for Automatic Teaching Operation) for first semester accounting courses. It contains information on lesson access, lists of acceptable abbreviations for…

  1. Public Accountancy Handbook.

    ERIC Educational Resources Information Center

    New York State Education Dept., Albany. Office of the Professions.

    The laws, rules and regulations of the State Education Department governing public accountancy practice in New York State are provided in this handbook. Licensure requirements are also described, and the forms for obtaining a license and first registration as a certified public accountant are provided. The booklet is divided into the following…

  2. Leadership for Accountability.

    ERIC Educational Resources Information Center

    Lashway, Larry

    2001-01-01

    This document explores issues of leadership for accountability and reviews five resources on the subject. These include: (1) "Accountability by Carrots and Sticks: Will Incentives and Sanctions Motivate Students, Teachers, and Administrators for Peak Performance?" (Larry Lashway); (2) "Organizing Schools for Teacher Learning" (Judith Warren…

  3. The Accountability Illusion: Arizona

    ERIC Educational Resources Information Center

    Thomas B. Fordham Institute, 2009

    2009-01-01

    The intent of the No Child Left Behind (NCLB) Act of 2001 is to hold schools accountable for ensuring that all their students achieve mastery in reading and math, with a particular focus on groups that have traditionally been left behind. Under NCLB, states submit accountability plans to the U.S. Department of Education detailing the rules and…

  4. The Accountability Illusion: Minnesota

    ERIC Educational Resources Information Center

    Thomas B. Fordham Institute, 2009

    2009-01-01

    The intent of the No Child Left Behind (NCLB) Act of 2001 is to hold schools accountable for ensuring that all their students achieve mastery in reading and math, with a particular focus on groups that have traditionally been left behind. Under NCLB, states submit accountability plans to the U.S. Department of Education detailing the rules and…

  5. The Accountability Illusion: Nevada

    ERIC Educational Resources Information Center

    Thomas B. Fordham Institute, 2009

    2009-01-01

    The intent of the No Child Left Behind (NCLB) Act of 2001 is to hold schools accountable for ensuring that all their students achieve mastery in reading and math, with a particular focus on groups that have traditionally been left behind. Under NCLB, states submit accountability plans to the U.S. Department of Education detailing the rules and…

  6. Teaching Accounting with Computers.

    ERIC Educational Resources Information Center

    Shaoul, Jean

    This paper addresses the numerous ways that computers may be used to enhance the teaching of accounting and business topics. It focuses on the pedagogical use of spreadsheet software to improve the conceptual coverage of accounting principles and practice, increase student understanding by involvement in the solution process, and reduce the amount…

  7. The Accountability Illusion: California

    ERIC Educational Resources Information Center

    Thomas B. Fordham Institute, 2009

    2009-01-01

    The intent of the No Child Left Behind (NCLB) Act of 2001 is to hold schools accountable for ensuring that all their students achieve mastery in reading and math, with a particular focus on groups that have traditionally been left behind. Under NCLB, states submit accountability plans to the U.S. Department of Education detailing the rules and…

  8. Accountability for What?

    ERIC Educational Resources Information Center

    Knowles, Rex; Knowles; Trudy

    2001-01-01

    Our emphasis on accountability overlooks children's differences. Half of all individuals who take a norm-referenced test will be below average. Should such students be pushed, mauled, and remediated or squeezed into a common learning mold? Holding teachers accountable for humane treatment of "whole children" is a worthier pursuit. (MLH)

  9. The Evolution of Accountability

    ERIC Educational Resources Information Center

    Webb, P. Taylor

    2011-01-01

    Campus 2020: Thinking ahead is a policy in British Columbia (BC), Canada, that attempted to hold universities accountable to performance. Within, I demonstrate how this Canadian articulation of educational accountability intended to develop "governmentality constellations" to control the university and regulate its knowledge output. This research…

  10. Accountability in Education.

    ERIC Educational Resources Information Center

    Chippendale, P. R., Ed.; Wilkes, Paula V., Ed.

    This collection of papers delivered at a conference on accountability held at Darling Downs Institute of Advanced Education in Australia examines the meaning of accountability in education for teachers, lecturers, government, parents, administrators, education authorities, and the society at large. In Part 1, W. G. Walker attempts to answer the…

  11. Accountability and Primary Healthcare

    PubMed Central

    Mukhi, Shaheena; Barnsley, Jan; Deber, Raisa B.

    2014-01-01

    This paper examines the accountability structures within primary healthcare (PHC) in Ontario; in particular, who is accountable for what and to whom, and the policy tools being used. Ontario has implemented a series of incremental reforms, using expenditure policy instruments, enforced through contractual agreements to provide a defined set of publicly financed services that are privately delivered, most often by family physicians. The findings indicate that reporting, funding, evaluation and governance accountability requirements vary across service provider models. Accountability to the funder and patients is most common. Agreements, incentives and compensation tools have been used but may be insufficient to ensure parties are being held responsible for their activities related to stated goals. Clear definitions of various governance structures, a cohesive approach to monitoring critical performance indicators and associated improvement strategies are important elements in operationalizing accountability and determining whether goals are being met. PMID:25305392

  12. Accountability and primary healthcare.

    PubMed

    Mukhi, Shaheena; Barnsley, Jan; Deber, Raisa B

    2014-09-01

    This paper examines the accountability structures within primary healthcare (PHC) in Ontario; in particular, who is accountable for what and to whom, and the policy tools being used. Ontario has implemented a series of incremental reforms, using expenditure policy instruments, enforced through contractual agreements to provide a defined set of publicly financed services that are privately delivered, most often by family physicians. The findings indicate that reporting, funding, evaluation and governance accountability requirements vary across service provider models. Accountability to the funder and patients is most common. Agreements, incentives and compensation tools have been used but may be insufficient to ensure parties are being held responsible for their activities related to stated goals. Clear definitions of various governance structures, a cohesive approach to monitoring critical performance indicators and associated improvement strategies are important elements in operationalizing accountability and determining whether goals are being met. PMID:25305392

  13. Holding Kids Accountable: Shaming with Compassion.

    ERIC Educational Resources Information Center

    Campbell, H. Allen; Revering, Andrew C.

    1997-01-01

    Describes the philosophy and procedures of Police Accountability Conferencing, a restorative justice approach in which police and school authorities, victims, offenders, and families are brought together in a process designed to hold youth accountable for their actions. Details the program's potential for reclaiming youth who have engaged in…

  14. RISK REDUCTION FOR MATERIAL ACCOUNTABILITY UPGRADES.

    SciTech Connect

    FISHBONE, L.G.; SISKIND, B.

    2005-05-16

    We present in this paper a method for evaluating explicitly the contribution of nuclear material accountability upgrades to risk reduction at nuclear facilities. The method yields the same types of values for conditional risk reduction that physical protection and material control upgrades yield. Thereby, potential material accountability upgrades can be evaluated for implementation in the same way that protection and control upgrades are evaluated.

  15. Assessment of Telomere Length in Archived Formalin-Fixed, Paraffinized Human Tissue Is Confounded by Chronological Age and Storage Duration

    PubMed Central

    2016-01-01

    Telomeres shorten with physiological aging but undergo substantial restoration during cancer immortalization. Increasingly, cancer studies utilize the archive of formalin-fixed, paraffin-embedded (FFPE) tissues in diagnostic pathology departments. Conceptually, such studies would be confounded by physiological telomere attrition and loss of DNA integrity from prolonged tissue storage. Our study aimed to investigate these two confounding factors. 145 FFPE tissues of surgically-resected, non-diseased appendixes were retrieved from our pathology archive, from years 2008 to 2014. Cases from 2013 to 2014 were categorized by patient chronological age (0–20 years, 21–40 years, 41–60 years, > 60 years). Telomere lengths of age categories were depicted by telomere/chromosome 2 centromere intensity ratio (TCR) revealed by quantitative fluorescence in situ hybridization. Material from individuals aged 0–20 years from years 2013/2014, 2011/2012, 2009/2010, and 2008 were compared for storage effect. Telomere integrity was assessed by telomere fluorescence intensity (TFI). Epithelial TCRs (mean ± SD) for the respective age groups were 4.84 ± 2.08, 3.64 ± 1.21, 2.03 ± 0.37, and 1.93 ± 0.45, whereas corresponding stromal TCRs were 5.16 ± 2.55, 3.84 ± 1.36, 2.49 ± 1.20, and 2.93 ± 1.24. A trend of inverse correlation with age in both epithelial and stromal tissues is supported by r = -0.69, p < 0.001 and r = -0.42, p < 0.001 respectively. Epithelial TFIs (mean ± SD) of years 2013/2014, 2011/2012, 2009/2010 and 2008 were 852.60 ± 432.46, 353.04 ± 127.12, 209.24 ± 55.57 and 429.22 ± 188.75 respectively. Generally, TFIs reduced with storage duration (r = -0.42, p < 0.001). Our findings agree that age-related telomere attrition occurs in normal somatic tissues, and suggest that an age-based reference can be established for telomere studies on FFPE tissues. We also showed that FFPE tissues archived beyond 2 years are suboptimal for telomere analysis. PMID:27598341

  16. Assessment of Telomere Length in Archived Formalin-Fixed, Paraffinized Human Tissue Is Confounded by Chronological Age and Storage Duration.

    PubMed

    Kong, Po-Lian; Looi, Lai-Meng; Lau, Tze-Pheng; Cheah, Phaik-Leng

    2016-01-01

    Telomeres shorten with physiological aging but undergo substantial restoration during cancer immortalization. Increasingly, cancer studies utilize the archive of formalin-fixed, paraffin-embedded (FFPE) tissues in diagnostic pathology departments. Conceptually, such studies would be confounded by physiological telomere attrition and loss of DNA integrity from prolonged tissue storage. Our study aimed to investigate these two confounding factors. 145 FFPE tissues of surgically-resected, non-diseased appendixes were retrieved from our pathology archive, from years 2008 to 2014. Cases from 2013 to 2014 were categorized by patient chronological age (0-20 years, 21-40 years, 41-60 years, > 60 years). Telomere lengths of age categories were depicted by telomere/chromosome 2 centromere intensity ratio (TCR) revealed by quantitative fluorescence in situ hybridization. Material from individuals aged 0-20 years from years 2013/2014, 2011/2012, 2009/2010, and 2008 were compared for storage effect. Telomere integrity was assessed by telomere fluorescence intensity (TFI). Epithelial TCRs (mean ± SD) for the respective age groups were 4.84 ± 2.08, 3.64 ± 1.21, 2.03 ± 0.37, and 1.93 ± 0.45, whereas corresponding stromal TCRs were 5.16 ± 2.55, 3.84 ± 1.36, 2.49 ± 1.20, and 2.93 ± 1.24. A trend of inverse correlation with age in both epithelial and stromal tissues is supported by r = -0.69, p < 0.001 and r = -0.42, p < 0.001 respectively. Epithelial TFIs (mean ± SD) of years 2013/2014, 2011/2012, 2009/2010 and 2008 were 852.60 ± 432.46, 353.04 ± 127.12, 209.24 ± 55.57 and 429.22 ± 188.75 respectively. Generally, TFIs reduced with storage duration (r = -0.42, p < 0.001). Our findings agree that age-related telomere attrition occurs in normal somatic tissues, and suggest that an age-based reference can be established for telomere studies on FFPE tissues. We also showed that FFPE tissues archived beyond 2 years are suboptimal for telomere analysis. PMID:27598341

  17. Accountability in delivering care.

    PubMed

    Castledine, G

    In the penultimate part of this series on issues in ward management facing charge nurses. George Castledine concentrates on the issue of accountability. The immensely powerful position of the charge nurse as arbitrator and co-ordinator of all health care given to the patient demands that helshe exercises this power responsibly and positively; hence, the crucial importance of accountability. The author explores this concept and also those of advocacy and conscientious objection. He concludes by suggesting that the ultimate area of accountability in nursing is the individual conscience of the practitioner and that in this may lie the key to the setting and maintenance of high standards of care.

  18. Environment- and eye-centered inhibitory cueing effects are both observed after a methodological confound is eliminated

    PubMed Central

    He, Tao; Ding, Yun; Wang, Zhiguo

    2015-01-01

    Inhibition of return (IOR), typically explored in cueing paradigms, is a performance cost associated with previously attended locations and has been suggested as a crucial attentional mechanism that biases orientation towards novelty. In their seminal IOR paper, Posner and Cohen (1984) showed that IOR is coded in spatiotopic or environment-centered coordinates. Recent studies, however, have consistently reported IOR effects in both spatiotopic and retinotopic (eye-centered) coordinates. One overlooked methodological confound of all previous studies is that the spatial gradient of IOR is not considered when selecting the baseline for estimating IOR effects. This methodological issue makes it difficult to tell if the IOR effects reported in previous studies were coded in retinotopic or spatiotopic coordinates, or in both. The present study addresses this issue with the incorporation of no-cue trials to a modified cueing paradigm in which the cue and target are always intervened by a gaze-shift. The results revealed that a) IOR is indeed coded in both spatiotopic and retinotopic coordinates, and b) the methodology of previous work may have underestimated spatiotopic and retinotopic IOR effects. PMID:26565380

  19. Application of Mycobacterium Leprae-specific cellular and serological tests for the differential diagnosis of leprosy from confounding dermatoses.

    PubMed

    Freitas, Aline Araújo; Hungria, Emerith Mayra; Costa, Maurício Barcelos; Sousa, Ana Lúcia Osório Maroccolo; Castilho, Mirian Lane Oliveira; Gonçalves, Heitor Sá; Pontes, Maria Araci Andrade; Duthie, Malcolm S; Stefani, Mariane Martins Araújo

    2016-10-01

    Mycobacterium leprae-specific serological and cell-mediated-immunity/CMI test were evaluated for the differential diagnosis of multibacillary/MB, and paucibacillary/PB leprosy from other dermatoses. Whole-blood assay/WBA/IFNγ stimulated with LID-1 antigen and ELISA tests for IgG to LID-1 and IgM to PGL-I were performed. WBA/LID-1/IFNγ production was observed in 72% PB, 11% MB leprosy, 38% dermatoses, 40% healthy endemic controls/EC. The receiver operating curve/ROC for WBA/LID-1 in PB versus other dermatoses showed 72.5% sensitivity, 61.5% specificity and an area-under-the-curve/AUC=0.75; 74% positive predictive value/PPV, 59% negative predictive value/NPV. Anti PGL-I serology was positive in 67% MB, 8% PB leprosy, 6% of other dermatoses; its sensitivity for MB=66%, specificity=93%, AUC=0.89; PPV=91%, NPV=72%. Anti-LID-1 serology was positive in 87% MB, 7% PB leprosy, all other participants were seronegative; 87.5% sensitivity for MB, 100% specificity, AUC=0.97; PPV=100%, NPV=88%. In highly endemic areas anti-LID-1/PGL-I serology and WBA/LID-1-represent useful tools for the differential diagnosis of leprosy from other confounding dermatoses.

  20. Confounding dynamic risk taking propensity with a momentum prognostic strategy: the case of the Columbia Card Task (CCT)

    PubMed Central

    Markiewicz, Łukasz; Kubińska, Elżbieta; Tyszka, Tadeusz

    2015-01-01

    Figner et al. (2009) developed the Columbia Card Task (CCT) to measure risk-taking attitudes. This tool consists of two versions: in the COLD version the decision maker needs to state in advance how many cards (out of 32) they want to turn over (so called static risk taking), in the HOT version they have the possibility of turning over all 32 cards one-by-one until they decide to finish (dynamic risk taking). We argue that the HOT version confounds an individual’s willingness to accept risk with their beliefs in trend continuation vs. trend reversal in a prognostic task. In two experimental studies we show that people believing in trend continuation (momentum subjects) turn over more cards than those believing in trend reversal (contrarians) in the HOT version of the task. However, this is not the case in the COLD version. Thus, we provide evidence that, when considered as a dynamic risk propensity measure, the number of turned over cards in the HOT version of the CCT is a contaminated measure and reflects two phenomena: (1) risk preference and (2) the decision-maker’s belief in trend continuation. We speculate that other dynamic risk taking measures can also be biased by a momentum strategy. PMID:26300799

  1. Reduced risk of pertussis in whole-cell compared to acellular vaccine recipients is not confounded by age or receipt of booster-doses.

    PubMed

    Sheridan, Sarah L; Ware, Robert S; Grimwood, Keith; Lambert, Stephen B

    2015-09-22

    Several observational studies provide evidence that acellular pertussis vaccines (aP) are less protective against pertussis disease than highly effective whole-cell pertussis vaccines (wP), however, concerns have been raised that some of these findings may be confounded by age. By undertaking age-stratified and restricted analyses on a cohort of Australian children primed with either aP-only, wP-only or mixed pertussis vaccine schedules, we demonstrate that compared to aP the association of wP with increased protection from pertussis is not confounded by age, nor by aP booster-dose receipt.

  2. Commentary: Overview of Developmental Perspectives on Creativity and the Realization of Potential.

    PubMed

    Runco, Mark A

    2016-01-01

    The articles in this issue of New Directions for Child and Adolescent Development nicely summarize recent findings about creativity and development. This commentary underscores some of the key ideas and puts them into a larger context (i.e., the corpus of creativity research). It pinpoints areas of agreement (e.g., the need to take both generative and convergent processes into account when examining developmental changes in creative behavior) but balances this with a discussion of concerns. These include (a) problems with the concept of Big C creativity, as it may confound the realization of creative potential, (b) lack of attention given to cultural relativity, and (c) inappropriate testing of divergent thinking. Still, the progress in the research is clear and the fulfillment of creative potentials increasingly likely. PMID:26994728

  3. The Politics of Evaluation and Accountability on the School Scene.

    ERIC Educational Resources Information Center

    Toro, Jose Orlando

    Politics of evaluation and accountability are not practiced solely by evaluators and accountants; everyone does it. This is because evaluation and accountability are fraught with decision situations which embody the potential to become political. Among sources of conflict in evaluation and accountability are questions of goals and priorities,…

  4. Student Academic Performance in Undergraduate Managerial-Accounting Courses

    ERIC Educational Resources Information Center

    Al-Twaijry, Abdulrahman Ali

    2010-01-01

    The author's purpose was to identify potential factors possibly affecting student performance in three sequential management-accounting courses: Managerial Accounting (MA), Cost Accounting (CA), and Advanced Managerial Accounting (AMA) within the Saudi Arabian context. The sample, which was used to test the developed hypotheses, included 312…

  5. Computerized material accounting

    SciTech Connect

    Claborn, J.; Erkkila, B.

    1995-07-01

    With the advent of fast, reliable database servers running on inexpensive networked personal computers, it is possible to create material accountability systems that are easy to learn, easy to use, and cost-effective to implement. Maintaining the material data in a relational database allows data to be viewed in ways that were previously very difficult. This paper describes a software and hardware platforms for the implementation of such an accountability system.

  6. Accounting for the environment.

    PubMed

    Lutz, E; Munasinghe, M

    1991-03-01

    Environmental awareness in the 1980s has led to efforts to improve the current UN System of National Accounts (SNA) for better measurement of the value of environmental resources when estimating income. National governments, the UN, the International Monetary Fund, and the World Bank are interested in solving this issue. The World Bank relies heavily on national aggregates in income accounts compiled by means of the SNA that was published in 1968 and stressed gross domestic product (GDP). GDP measures mainly market activity, but it takes does not consider the consumption of natural capital, and indirectly inhibits sustained development. The deficiencies of the current method of accounting are inconsistent treatment of manmade and natural capital, the omission of natural resources and their depletion from balance sheets, and pollution cleanup costs from national income. In the calculation of GDP pollution is overlooked, and beneficial environmental inputs are valued at zero. The calculation of environmentally adjusted net domestic product (EDP) and environmentally adjusted net income (ENI) would lower income and growth rate, as the World Resources Institute found with respect to Indonesia for 1971-84. When depreciation for oil, timber, and top soil was included the net domestic product (NDP) was only 4% compared with a 7.1% GDP. The World Bank has advocated environmental accounting since 1983 in SNA revisions. The 1989 revised Blue Book of the SNA takes environment concerns into account. Relevant research is under way in Mexico and Papua New Guinea using the UN Statistical Office framework as a system for environmentally adjusted economic accounts that computes EDP and ENI and integrates environmental data with national accounts while preserving SNA concepts. PMID:12285741

  7. Modeling Lung Carcinogenesis in Radon-Exposed Miner Cohorts: Accounting for Missing Information on Smoking.

    PubMed

    van Dillen, Teun; Dekkers, Fieke; Bijwaard, Harmen; Brüske, Irene; Wichmann, H-Erich; Kreuzer, Michaela; Grosche, Bernd

    2016-05-01

    Epidemiological miner cohort data used to estimate lung cancer risks related to occupational radon exposure often lack cohort-wide information on exposure to tobacco smoke, a potential confounder and important effect modifier. We have developed a method to project data on smoking habits from a case-control study onto an entire cohort by means of a Monte Carlo resampling technique. As a proof of principle, this method is tested on a subcohort of 35,084 former uranium miners employed at the WISMUT company (Germany), with 461 lung cancer deaths in the follow-up period 1955-1998. After applying the proposed imputation technique, a biologically-based carcinogenesis model is employed to analyze the cohort's lung cancer mortality data. A sensitivity analysis based on a set of 200 independent projections with subsequent model analyses yields narrow distributions of the free model parameters, indicating that parameter values are relatively stable and independent of individual projections. This technique thus offers a possibility to account for unknown smoking habits, enabling us to unravel risks related to radon, to smoking, and to the combination of both.

  8. Modeling Lung Carcinogenesis in Radon-Exposed Miner Cohorts: Accounting for Missing Information on Smoking.

    PubMed

    van Dillen, Teun; Dekkers, Fieke; Bijwaard, Harmen; Brüske, Irene; Wichmann, H-Erich; Kreuzer, Michaela; Grosche, Bernd

    2016-05-01

    Epidemiological miner cohort data used to estimate lung cancer risks related to occupational radon exposure often lack cohort-wide information on exposure to tobacco smoke, a potential confounder and important effect modifier. We have developed a method to project data on smoking habits from a case-control study onto an entire cohort by means of a Monte Carlo resampling technique. As a proof of principle, this method is tested on a subcohort of 35,084 former uranium miners employed at the WISMUT company (Germany), with 461 lung cancer deaths in the follow-up period 1955-1998. After applying the proposed imputation technique, a biologically-based carcinogenesis model is employed to analyze the cohort's lung cancer mortality data. A sensitivity analysis based on a set of 200 independent projections with subsequent model analyses yields narrow distributions of the free model parameters, indicating that parameter values are relatively stable and independent of individual projections. This technique thus offers a possibility to account for unknown smoking habits, enabling us to unravel risks related to radon, to smoking, and to the combination of both. PMID:27198876

  9. Issues Relating to Confounding and Meta-analysis When Including Non-Randomized Studies in Systematic Reviews on the Effects of Interventions

    ERIC Educational Resources Information Center

    Valentine, Jeffrey C.; Thompson, Simon G.

    2013-01-01

    Background: Confounding caused by selection bias is often a key difference between non-randomized studies (NRS) and randomized controlled trials (RCTs) of interventions. Key methodological issues: In this third paper of the series, we consider issues relating to the inclusion of NRS in systematic reviews on the effects of interventions. We discuss…

  10. Using Rich Data on Comorbidities in Case-Control Study Design with Electronic Health Record Data Improves Control of Confounding in the Detection of Adverse Drug Reactions

    PubMed Central

    Chase, Herbert

    2016-01-01

    Recent research has suggested that the case-control study design, unlike the self-controlled study design, performs poorly in controlling confounding in the detection of adverse drug reactions (ADRs) from administrative claims and electronic health record (EHR) data, resulting in biased estimates of the causal effects of drugs on health outcomes of interest (HOI) and inaccurate confidence intervals. Here we show that using rich data on comorbidities and automatic variable selection strategies for selecting confounders can better control confounding within a case-control study design and provide a more solid basis for inference regarding the causal effects of drugs on HOIs. Four HOIs are examined: acute kidney injury, acute liver injury, acute myocardial infarction and gastrointestinal ulcer hospitalization. For each of these HOIs we use a previously published reference set of positive and negative control drugs to evaluate the performance of our methods. Our methods have AUCs that are often substantially higher than the AUCs of a baseline method that only uses demographic characteristics for confounding control. Our methods also give confidence intervals for causal effect parameters that cover the expected no effect value substantially more often than this baseline method. The case-control study design, unlike the self-controlled study design, can be used in the fairly typical setting of EHR databases without longitudinal information on patients. With our variable selection method, these databases can be more effectively used for the detection of ADRs. PMID:27716785

  11. Confounding effect of EEG implantation surgery: Inadequacy of surgical control in a two hit model of temporal lobe epilepsy.

    PubMed

    Balzekas, Irena; Hernandez, Jose; White, Jacob; Koh, Sookyong

    2016-05-27

    In rodent models of epilepsy, EEG implantation surgery is an essential modality to evaluate electrographic seizures. The inflammatory consequences of EEG electrode-implantation and their resultant effects on seizure susceptibility are unclear. We evaluated electrode-implantation in a two-hit model of epileptogenesis in C57BL/6 mice that included brief, recurrent febrile seizures (FS) at P14 and kainic acid induced seizures (KA-SZ) at P28. During KA-SZ, latencies to first electrographic and behavioral seizures, seizure severity, and KA dose sensitivity were measured. Mice that received subdural screw electrode implants at P25 for EEG monitoring at P28 had significantly shorter latencies to seizures than sham mice, regardless of early life seizure experience. Electrode-implanted mice were sensitive to low dose KA as shown by high mortality rate at KA doses above 10mg/kg. We then directly compared electrode-implantation and KA-SZ in seizure naive CX3CR1(GFP/+) transgenic C57BL/6 mice, wherein microglia express green fluorescent protein (GFP), to determine if microglia activation related to surgery was associated with the increased seizure susceptibility in electrode-implanted mice from the two-hit model. Hippocampal microglia activation, as demonstrated by percent area GFP signal and GFP positive cell counts, prior to seizures was indistinguishable between electrode-implanted mice and controls, but was significantly greater in electrode-implanted mice following seizures. Electrode-implantation had a confounding priming effect on the inflammatory response to subsequent seizures. PMID:27095588

  12. Accounting Issues: An Essay Series Part VII--Liabilities

    ERIC Educational Resources Information Center

    Laux, Judy

    2008-01-01

    This article, the seventh in the series, presents accounting for liabilities along with some related conceptual and measurement issues. Additional coverage is devoted to potential ethical dilemmas and both theoretical and empirical literature related to this set of accounting elements.

  13. 17 CFR 17.01 - Identification of special accounts, volume threshold accounts, and omnibus accounts.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... accounts, volume threshold accounts, and omnibus accounts. 17.01 Section 17.01 Commodity and Securities..., CLEARING MEMBERS, AND FOREIGN BROKERS § 17.01 Identification of special accounts, volume threshold accounts... in § 17.02(b). (b) Identification of volume threshold accounts. Each clearing member shall...

  14. A Pariah Profession? Some Student Perceptions of Accounting and Accountancy.

    ERIC Educational Resources Information Center

    Fisher, Roy; Murphy, Vivienne

    1995-01-01

    Existing literature and a survey of 106 undergraduate accounting students in the United Kingdom were analyzed for perceptions of the accounting profession and the academic discipline of accounting. Results suggest that among accounting and nonaccounting students alike, there exist coexisting perceptions of accounting as having high status and low…

  15. 18 CFR 367.2320 - Account 232, Accounts payable.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 18 Conservation of Power and Water Resources 1 2014-04-01 2014-04-01 false Account 232, Accounts... POWER ACT AND NATURAL GAS ACT UNIFORM SYSTEM OF ACCOUNTS FOR CENTRALIZED SERVICE COMPANIES SUBJECT TO... ACT Balance Sheet Chart of Accounts Current and Accrued Liabilities § 367.2320 Account 232,...

  16. 18 CFR 367.2320 - Account 232, Accounts payable.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Account 232, Accounts... POWER ACT AND NATURAL GAS ACT UNIFORM SYSTEM OF ACCOUNTS FOR CENTRALIZED SERVICE COMPANIES SUBJECT TO... ACT Balance Sheet Chart of Accounts Current and Accrued Liabilities § 367.2320 Account 232,...

  17. 18 CFR 367.2320 - Account 232, Accounts payable.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 18 Conservation of Power and Water Resources 1 2012-04-01 2012-04-01 false Account 232, Accounts... POWER ACT AND NATURAL GAS ACT UNIFORM SYSTEM OF ACCOUNTS FOR CENTRALIZED SERVICE COMPANIES SUBJECT TO... ACT Balance Sheet Chart of Accounts Current and Accrued Liabilities § 367.2320 Account 232,...

  18. 18 CFR 367.2320 - Account 232, Accounts payable.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 18 Conservation of Power and Water Resources 1 2011-04-01 2011-04-01 false Account 232, Accounts... POWER ACT AND NATURAL GAS ACT UNIFORM SYSTEM OF ACCOUNTS FOR CENTRALIZED SERVICE COMPANIES SUBJECT TO... ACT Balance Sheet Chart of Accounts Current and Accrued Liabilities § 367.2320 Account 232,...

  19. 18 CFR 367.2320 - Account 232, Accounts payable.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 18 Conservation of Power and Water Resources 1 2013-04-01 2013-04-01 false Account 232, Accounts... POWER ACT AND NATURAL GAS ACT UNIFORM SYSTEM OF ACCOUNTS FOR CENTRALIZED SERVICE COMPANIES SUBJECT TO... ACT Balance Sheet Chart of Accounts Current and Accrued Liabilities § 367.2320 Account 232,...

  20. Excel in the Accounting Curriculum: Perceptions from Accounting Professors

    ERIC Educational Resources Information Center

    Ramachandran Rackliffe, Usha; Ragland, Linda

    2016-01-01

    Public accounting firms emphasize the importance of accounting graduates being proficient in Excel. Since many accounting graduates often aspire to work in public accounting, a question arises as to whether there should be an emphasis on Excel in accounting education. The purpose of this paper is to specifically look at this issue by examining…

  1. STAR facility tritium accountancy

    SciTech Connect

    Pawelko, R. J.; Sharpe, J. P.; Denny, B. J.

    2008-07-15

    The Safety and Tritium Applied Research (STAR) facility has been established to provide a laboratory infrastructure for the fusion community to study tritium science associated with the development of safe fusion energy and other technologies. STAR is a radiological facility with an administrative total tritium inventory limit of 1.5 g (14,429 Ci) [1]. Research studies with moderate tritium quantities and various radionuclides are performed in STAR. Successful operation of the STAR facility requires the ability to receive, inventory, store, dispense tritium to experiments, and to dispose of tritiated waste while accurately monitoring the tritium inventory in the facility. This paper describes tritium accountancy in the STAR facility. A primary accountancy instrument is the tritium Storage and Assay System (SAS): a system designed to receive, assay, store, and dispense tritium to experiments. Presented are the methods used to calibrate and operate the SAS. Accountancy processes utilizing the Tritium Cleanup System (TCS), and the Stack Tritium Monitoring System (STMS) are also discussed. Also presented are the equations used to quantify the amount of tritium being received into the facility, transferred to experiments, and removed from the facility. Finally, the STAR tritium accountability database is discussed. (authors)

  2. STAR Facility Tritium Accountancy

    SciTech Connect

    R. J. Pawelko; J. P. Sharpe; B. J. Denny

    2007-09-01

    The Safety and Tritium Applied Research (STAR) facility has been established to provide a laboratory infrastructure for the fusion community to study tritium science associated with the development of safe fusion energy and other technologies. STAR is a radiological facility with an administrative total tritium inventory limit of 1.5g (14,429 Ci) [1]. Research studies with moderate tritium quantities and various radionuclides are performed in STAR. Successful operation of the STAR facility requires the ability to receive, inventory, store, dispense tritium to experiments, and to dispose of tritiated waste while accurately monitoring the tritium inventory in the facility. This paper describes tritium accountancy in the STAR facility. A primary accountancy instrument is the tritium Storage and Assay System (SAS): a system designed to receive, assay, store, and dispense tritium to experiments. Presented are the methods used to calibrate and operate the SAS. Accountancy processes utilizing the Tritium Cleanup System (TCS), and the Stack Tritium Monitoring System (STMS) are also discussed. Also presented are the equations used to quantify the amount of tritium being received into the facility, transferred to experiments, and removed from the facility. Finally, the STAR tritium accountability database is discussed.

  3. Planning for Accountability.

    ERIC Educational Resources Information Center

    Cuneo, Tim; Bell, Shareen; Welsh-Gray, Carol

    1999-01-01

    Through its Challenge 2000 program, Joint Venture: Silicon Valley Network's 21st Century Education Initiative has been working with K-12 schools to improve student performance in literature, math, and science. Clearly stated standards, appropriate assessments, formal monitoring, critical friends, and systemwide accountability are keys to success.…

  4. Student Attendance Accounting Manual.

    ERIC Educational Resources Information Center

    Freitas, Joseph M.

    In response to state legislation authorizing procedures for changes in academic calendars and measurement of student workload in California community colleges, this manual from the Chancellor's Office provides guidelines for student attendance accounting. Chapter 1 explains general items such as the academic calendar, admissions policies, student…

  5. Accountability for Productivity

    ERIC Educational Resources Information Center

    Wellman, Jane

    2010-01-01

    Productivity gains in higher education won't be made just by improving cost effectiveness or even performance. They need to be documented, communicated, and integrated into a strategic agenda to increase attainment. This requires special attention to "accountability" for productivity, meaning public presentation and communication of evidence about…

  6. The Accountability Illusion

    ERIC Educational Resources Information Center

    Cronin, John; Dahlin, Michael; Xiang, Yun; McCahon, Donna

    2009-01-01

    The intent of the No Child Left Behind (NCLB) Act of 2001 is to hold schools accountable for ensuring that all their students achieve mastery in reading and math, with a particular focus on groups that have traditionally been left behind. Under NCLB, states have leeway to: (1) Craft their own academic standards, select their own tests, and define…

  7. Accounting for What Counts

    ERIC Educational Resources Information Center

    Milner, Joseph O.; Ferran, Joan E.; Martin, Katharine Y.

    2003-01-01

    No Child Left Behind legislation makes it clear that outside evaluators determine what gets taught in the classroom. It is important to ensure they measure what truly counts in school. This fact is poignantly and sadly true for the under funded, poorly resourced, "low performing" schools that may be hammered by administration accountants in the…

  8. Professional Capital as Accountability

    ERIC Educational Resources Information Center

    Fullan, Michael; Rincón-Gallardo, Santiago; Hargreaves, Andy

    2015-01-01

    This paper seeks to clarify and spells out the responsibilities of policy makers to create the conditions for an effective accountability system that produces substantial improvements in student learning, strengthens the teaching profession, and provides transparency of results to the public. The authors point out that U.S. policy makers will need…

  9. Accountability: A Rationale.

    ERIC Educational Resources Information Center

    Brademas, John

    1974-01-01

    The idea of accountability has by now been interpreted in ways which are different enough from one another to have permitted a certain ambiguity to creep into the notion in its present use within the educational community. The principal purpose of this report is, therefore, to try to set forth some clearer statement of what the idea of…

  10. Fiscal Accounting Manual.

    ERIC Educational Resources Information Center

    California State Dept. of Housing and Community Development, Sacramento. Indian Assistance Program.

    Written in simple, easy to understand form, the manual provides a vehicle for the untrained person in bookkeeping to control funds received from grants for Indian Tribal Councils and Indian organizations. The method used to control grants (federal, state, or private) is fund accounting, designed to organize rendering services on a non-profit…

  11. Curtail Accountability, Cultivate Attainability

    ERIC Educational Resources Information Center

    Wraga, William G.

    2011-01-01

    The current test-driven accountability movement, codified in the No Child Left Behind Act of 2001 ([NCLB] 2002), was a misguided idea that will have the effect not of improving the education of children and youth, but of indicting the public school system of the United States. To improve education in the United States, politicians, policy makers,…

  12. Legal responsibility and accountability.

    PubMed

    Cox, Chris

    2010-06-01

    Shifting boundaries in healthcare roles have led to anxiety among some nurses about their legal responsibilities and accountabilities. This is partly because of a lack of education about legal principles that underpin healthcare delivery. This article explains the law in terms of standards of care, duty of care, vicarious liability and indemnity insurance.

  13. Accounting 202, 302.

    ERIC Educational Resources Information Center

    Manitoba Dept. of Education, Winnipeg.

    This teaching guide consists of guidelines for conducting two secondary-level introductory accounting courses. Intended for vocational business education students, the courses are designed to introduce financial principles and practices important to personal and business life, to promote development of clerical and bookkeeping skills sufficient…

  14. Democracy, Accountability, and Education

    ERIC Educational Resources Information Center

    Levinson, Meira

    2011-01-01

    Educational standards, assessments, and accountability systems are of immense political moment around the world. But there is no developed theory exploring the role that these systems should play within a democratic polity in particular. On the one hand, well-designed standards are public goods, supported by assessment and accountability…

  15. Educational Accounting Procedures.

    ERIC Educational Resources Information Center

    Tidwell, Sam B.

    This chapter of "Principles of School Business Management" reviews the functions, procedures, and reports with which school business officials must be familiar in order to interpret and make decisions regarding the school district's financial position. Among the accounting functions discussed are financial management, internal auditing, annual…

  16. CEBAF beam loss accounting

    SciTech Connect

    Ursic, R.; Mahoney, K.; Hovater, C.; Hutton, A.; Sinclair, C.

    1995-12-31

    This paper describes the design and implementation of a beam loss accounting system for the CEBAF electron accelerator. This system samples the beam curent throughout the beam path and measures the beam current accurately. Personnel Safety and Machine Protection systems use this system to turn off the beam when hazardous beam losses occur.

  17. MATERIAL CONTROL ACCOUNTING INMM

    SciTech Connect

    Hasty, T.

    2009-06-14

    Since 1996, the Mining and Chemical Combine (MCC - formerly known as K-26), and the United States Department of Energy (DOE) have been cooperating under the cooperative Nuclear Material Protection, Control and Accounting (MPC&A) Program between the Russian Federation and the U.S. Governments. Since MCC continues to operate a reactor for steam and electricity production for the site and city of Zheleznogorsk which results in production of the weapons grade plutonium, one of the goals of the MPC&A program is to support implementation of an expanded comprehensive nuclear material control and accounting (MC&A) program. To date MCC has completed upgrades identified in the initial gap analysis and documented in the site MC&A Plan and is implementing additional upgrades identified during an update to the gap analysis. The scope of these upgrades includes implementation of MCC organization structure relating to MC&A, establishing material balance area structure for special nuclear materials (SNM) storage and bulk processing areas, and material control functions including SNM portal monitors at target locations. Material accounting function upgrades include enhancements in the conduct of physical inventories, limit of error inventory difference procedure enhancements, implementation of basic computerized accounting system for four SNM storage areas, implementation of measurement equipment for improved accountability reporting, and both new and revised site-level MC&A procedures. This paper will discuss the implementation of MC&A upgrades at MCC based on the requirements established in the comprehensive MC&A plan developed by the Mining and Chemical Combine as part of the MPC&A Program.

  18. Radiology applications of financial accounting.

    PubMed

    Leibenhaut, Mark H

    2005-03-01

    A basic knowledge of financial accounting can help radiologists analyze business opportunities and examine the potential impacts of new technology or predict the adverse consequences of new competitors entering their service area. The income statement, balance sheet, and cash flow statement are the three basic financial statements that document the current financial position of the radiology practice and allow managers to monitor the ongoing financial operations of the enterprise. Pro forma, or hypothetical, financial statements can be generated to predict the financial impact of specific business decisions or investments on the profitability of the practice. Sensitivity analysis, or what-if scenarios, can be performed to determine the potential impact of changing key revenue, investment, operating cost or financial assumptions. By viewing radiology as both a profession and a business, radiologists can optimize their use of scarce economic resources and maximize the return on their financial investments.

  19. Radiology applications of financial accounting.

    PubMed

    Leibenhaut, Mark H

    2005-03-01

    A basic knowledge of financial accounting can help radiologists analyze business opportunities and examine the potential impacts of new technology or predict the adverse consequences of new competitors entering their service area. The income statement, balance sheet, and cash flow statement are the three basic financial statements that document the current financial position of the radiology practice and allow managers to monitor the ongoing financial operations of the enterprise. Pro forma, or hypothetical, financial statements can be generated to predict the financial impact of specific business decisions or investments on the profitability of the practice. Sensitivity analysis, or what-if scenarios, can be performed to determine the potential impact of changing key revenue, investment, operating cost or financial assumptions. By viewing radiology as both a profession and a business, radiologists can optimize their use of scarce economic resources and maximize the return on their financial investments. PMID:17411807

  20. The Persistent Problems and Confounding Challenges of Educator Incentives: The Case of TIF in Prince George's County, Maryland

    ERIC Educational Resources Information Center

    Rice, Jennifer King; Malen, Betty; Baumann, Paul; Chen, Elke; Dougherty, Amy; Hyde, Laura; Jackson, Cara; Jacobson, Reuben; McKithen, Clarissa

    2012-01-01

    While education accountability systems emphasize teacher quality as a prerequisite for student learning, education administrators have struggled to staff low-performing schools with effective teachers. Fueled in part by the federal Teacher Incentive Fund, compensation reforms have gained center stage status among strategies aimed at improving…

  1. Iowa Community Colleges Accounting Manual.

    ERIC Educational Resources Information Center

    Iowa State Dept. of Education, Des Moines. Div. of Community Colleges and Workforce Preparation.

    This document describes account classifications and definitions for the accounting system of the Iowa community colleges. In view of the objectives of the accounting system, it is necessary to segregate the assets of the community college according to its source and intended use. Additionally, the accounting system should provide for accounting by…

  2. Harnessing Facebook for Student Engagement in Accounting Education: Guiding Principles for Accounting Students and Educators

    ERIC Educational Resources Information Center

    Stone, Gerard; Fiedler, Brenton Andrew; Kandunias, Chris

    2014-01-01

    This paper proposes principles to guide accounting students' and accounting educators' use of Facebook as an educational resource to engage students with their learning. A body of cross-disciplinary research has investigated potential applications of Facebook to invigorate student engagement. Generic guidelines for educators who are contemplating…

  3. Managing global accounts.

    PubMed

    Yip, George S; Bink, Audrey J M

    2007-09-01

    Global account management--which treats a multinational customer's operations as one integrated account, with coherent terms for pricing, product specifications, and service--has proliferated over the past decade. Yet according to the authors' research, only about a third of the suppliers that have offered GAM are pleased with the results. The unhappy majority may be suffering from confusion about when, how, and to whom to provide it. Yip, the director of research and innovation at Capgemini, and Bink, the head of marketing communications at Uxbridge College, have found that GAM can improve customer satisfaction by 20% or more and can raise both profits and revenues by at least 15% within just a few years of its introduction. They provide guidelines to help companies achieve similar results. The first steps are determining whether your products or services are appropriate for GAM, whether your customers want such a program, whether those customers are crucial to your strategy, and how GAM might affect your competitive advantage. If moving forward makes sense, the authors' exhibit, "A Scorecard for Selecting Global Accounts," can help you target the right customers. The final step is deciding which of three basic forms to offer: coordination GAM (in which national operations remain relatively strong), control GAM (in which the global operation and the national operations are fairly balanced), and separate GAM (in which a new business unit has total responsibility for global accounts). Given the difficulty and expense of providing multiple varieties, the vast majority of companies should initially customize just one---and they should be careful not to start with a choice that is too ambitious for either themselves or their customers to handle.

  4. First-Person Accounts.

    ERIC Educational Resources Information Center

    Gribs, H.; And Others

    1995-01-01

    Personal accounts describe the lives of 2 individuals with deaf-blindness, one an 87-year-old woman who was deaf from birth and became totally blind over a 50-year period and the other of a woman who became deaf-blind as a result of a fever at the age of 7. Managing activities of daily life and experiencing sensory hallucinations are among topics…

  5. Managing global accounts.

    PubMed

    Yip, George S; Bink, Audrey J M

    2007-09-01

    Global account management--which treats a multinational customer's operations as one integrated account, with coherent terms for pricing, product specifications, and service--has proliferated over the past decade. Yet according to the authors' research, only about a third of the suppliers that have offered GAM are pleased with the results. The unhappy majority may be suffering from confusion about when, how, and to whom to provide it. Yip, the director of research and innovation at Capgemini, and Bink, the head of marketing communications at Uxbridge College, have found that GAM can improve customer satisfaction by 20% or more and can raise both profits and revenues by at least 15% within just a few years of its introduction. They provide guidelines to help companies achieve similar results. The first steps are determining whether your products or services are appropriate for GAM, whether your customers want such a program, whether those customers are crucial to your strategy, and how GAM might affect your competitive advantage. If moving forward makes sense, the authors' exhibit, "A Scorecard for Selecting Global Accounts," can help you target the right customers. The final step is deciding which of three basic forms to offer: coordination GAM (in which national operations remain relatively strong), control GAM (in which the global operation and the national operations are fairly balanced), and separate GAM (in which a new business unit has total responsibility for global accounts). Given the difficulty and expense of providing multiple varieties, the vast majority of companies should initially customize just one---and they should be careful not to start with a choice that is too ambitious for either themselves or their customers to handle. PMID:17886487

  6. Hospitals' Internal Accountability

    PubMed Central

    Kraetschmer, Nancy; Jass, Janak; Woodman, Cheryl; Koo, Irene; Kromm, Seija K.; Deber, Raisa B.

    2014-01-01

    This study aimed to enhance understanding of the dimensions of accountability captured and not captured in acute care hospitals in Ontario, Canada. Based on an Ontario-wide survey and follow-up interviews with three acute care hospitals in the Greater Toronto Area, we found that the two dominant dimensions of hospital accountability being reported are financial and quality performance. These two dimensions drove both internal and external reporting. Hospitals' internal reports typically included performance measures that were required or mandated in external reports. Although respondents saw reporting as a valuable mechanism for hospitals and the health system to monitor and track progress against desired outcomes, multiple challenges with current reporting requirements were communicated, including the following: 58% of survey respondents indicated that performance-reporting resources were insufficient; manual data capture and performance reporting were prevalent, with the majority of hospitals lacking sophisticated tools or technology to effectively capture, analyze and report performance data; hospitals tended to focus on those processes and outcomes with high measurability; and 53% of respondents indicated that valuable cross-system accountability, performance measures or both were not captured by current reporting requirements. PMID:25305387

  7. Hospitals' internal accountability.

    PubMed

    Kraetschmer, Nancy; Jass, Janak; Woodman, Cheryl; Koo, Irene; Kromm, Seija K; Deber, Raisa B

    2014-09-01

    This study aimed to enhance understanding of the dimensions of accountability captured and not captured in acute care hospitals in Ontario, Canada. Based on an Ontario-wide survey and follow-up interviews with three acute care hospitals in the Greater Toronto Area, we found that the two dominant dimensions of hospital accountability being reported are financial and quality performance. These two dimensions drove both internal and external reporting. Hospitals' internal reports typically included performance measures that were required or mandated in external reports. Although respondents saw reporting as a valuable mechanism for hospitals and the health system to monitor and track progress against desired outcomes, multiple challenges with current reporting requirements were communicated, including the following: 58% of survey respondents indicated that performance-reporting resources were insufficient; manual data capture and performance reporting were prevalent, with the majority of hospitals lacking sophisticated tools or technology to effectively capture, analyze and report performance data; hospitals tended to focus on those processes and outcomes with high measurability; and 53% of respondents indicated that valuable cross-system accountability, performance measures or both were not captured by current reporting requirements. PMID:25305387

  8. Perceived stress in multiple sclerosis: The potential role of mindfulness in health and wellbeing

    PubMed Central

    Senders, Angela; Bourdette, Dennis; Hanes, Douglas; Yadav, Vijayshree; Shinto, Lynne

    2014-01-01

    Stressful life events are associated with worsening neurological symptoms and decreased quality of life in multiple sclerosis (MS). Mindful-consciousness can alter the impact of stressful events and has potential to improve health outcomes in MS. This study evaluated the relationship between trait mindfulness and perceived stress, coping, and resilience in people with MS. Quality of life was assessed as a secondary outcome. 119 people with confirmed MS completed the Five-facet Mindfulness Questionnaire, Perceived Stress Scale, Brief Coping Orientation for Problem Experiences, Connor-Davidson Resilience Scale, and the SF-36. Greater trait mindfulness was significantly associated with decreased psychological stress, better coping skills, increased resilience, and higher quality of life. After controlling for confounders, mindfulness accounted for 25% of the variation in perceived stress scores and 44% of the variation in resilience scores. Results support further investigation of mindfulness training to enhance psychological resilience and improve wellbeing for those living with MS. PMID:24647090

  9. Perceived stress in multiple sclerosis: the potential role of mindfulness in health and well-being.

    PubMed

    Senders, Angela; Bourdette, Dennis; Hanes, Douglas; Yadav, Vijayshree; Shinto, Lynne

    2014-04-01

    Stressful life events are associated with worsening neurological symptoms and decreased quality of life in multiple sclerosis (MS). Mindful consciousness can alter the impact of stressful events and has potential to improve health outcomes in MS. This study evaluated the relationship between trait mindfulness and perceived stress, coping, and resilience in people with MS. Quality of life was assessed as a secondary outcome. One hundred nineteen people with confirmed MS completed the Five-Facet Mindfulness Questionnaire, Perceived Stress Scale, Brief Coping Orientation for Problem Experiences, Connor-Davidson Resilience Scale, and Medical Outcome Study Short Form-36. Greater trait mindfulness was significantly associated with decreased psychological stress, better coping skills, increased resilience, and higher quality of life. After investigators controlled for confounders, mindfulness accounted for 25% of the variation in perceived stress scores and 44% of the variation in resilience scores. Results support further investigation of mindfulness training to enhance psychological resilience and improve well-being for those living with MS.

  10. Estimating the monetary value of willingness to pay for E-book reader's attributes using partially confounded factorial conjoint choice experiment

    NASA Astrophysics Data System (ADS)

    Yong, Chin-Khian

    2013-09-01

    A partially confounded factorial conjoint choice experiments design was used to examine the monetary value of the willingness to pay for E-book Reader's attributes. Conjoint analysis is an efficient, cost-effective, and most widely used quantitative method in marketing research to understand consumer preferences and value trade-off. Value can be interpreted by customer or consumer as the received of multiple benefits from a price that was paid. The monetary value of willingness to pay for battery life, internal memory, external memory, screen size, text to Speech, touch screen, and converting handwriting to digital text of E-book reader were estimated in this study. Due to the significant interaction effect of the attributes with the price, the monetary values for the seven attributes were found to be different at different values of odds of purchasing versus not purchasing. The significant interactions effects were one of the main contribution of the partially confounded factorial conjoint choice experiment.

  11. Teaching Elementary Accounting to Non-Accounting Majors

    ERIC Educational Resources Information Center

    Lloyd, Cynthia B.; Abbey, Augustus

    2009-01-01

    A central recurring theme in business education is the optimal strategy for improving introductory accounting, the gateway subject of business education. For many students, especially non-accounting majors, who are required to take introductory accounting as a requirement of the curriculum, introductory accounting has become a major obstacle for…

  12. New Frontiers: Training Forensic Accountants within the Accounting Program

    ERIC Educational Resources Information Center

    Ramaswamy, Vinita

    2007-01-01

    Accountants have recently been subject to very unpleasant publicity following the collapse of Enron and other major companies. There has been a plethora of accounting failures and accounting restatements of falsified earnings, with litigations and prosecutions taking place every day. As the FASB struggles to tighten the loopholes in accounting,…

  13. 18 CFR 367.1420 - Account 142, Customer accounts receivable.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ..., FEDERAL POWER ACT AND NATURAL GAS ACT UNIFORM SYSTEM OF ACCOUNTS FOR CENTRALIZED SERVICE COMPANIES SUBJECT... GAS ACT Balance Sheet Chart of Accounts Current and Accrued Assets § 367.1420 Account 142, Customer... merchandising, jobbing and contract work. This account must not include amounts due from associate companies....

  14. Annual survival estimation of migratory songbirds confounded by incomplete breeding site-fidelity: Study designs that may help

    USGS Publications Warehouse

    Marshall, M.R.; Diefenbach, D.R.; Wood, L.A.; Cooper, R.J.

    2004-01-01

    Many species of bird exhibit varying degrees of site-fidelity to the previous year's territory or breeding area, a phenomenon we refer to as incomplete breeding site-fidelity. If the territory they occupy is located beyond the bounds of the study area or search area (i.e., they have emigrated from the study area), the bird will go undetected and is therefore indistinguishable from dead individuals in capture-mark-recapture studies. Differential emigration rates confound inferences regarding differences in survival between sexes and among species if apparent survival rates are used as estimates of true survival. Moreover, the bias introduced by using apparent survival rates for true survival rates can have profound effects on the predictions of population persistence through time, source/sink dynamics, and other aspects of life-history theory. We investigated four study design and analysis approaches that result in apparent survival estimates that are closer to true survival estimates. Our motivation for this research stemmed from a multi-year capture-recapture study of Prothonotary Warblers (Protonotaria citrea) on multiple study plots within a larger landscape of suitable breeding habitat where substantial inter-annual movements of marked individuals among neighboring study plots was documented. We wished to quantify the effects of this type of movement on annual survival estimation. The first two study designs we investigated involved marking birds in a core area and resighting them in the core as well as an area surrounding the core. For the first of these two designs, we demonstrated that as the resighting area surrounding the core gets progressively larger, and more "emigrants" are resighted, apparent survival estimates begin to approximate true survival rates (bias < 0.01). However, given observed inter-annual movements of birds, it is likely to be logistically impractical to resight birds on sufficiently large surrounding areas to minimize bias. Therefore

  15. Performance and Accountability Report

    NASA Technical Reports Server (NTRS)

    2003-01-01

    The NASA Fiscal Year 2002 Performance and Accountability Report is presented. Over the past year, significant changes have been implemented to greatly improve NASA's management while continuing to break new ground in science and technology. Excellent progress has been made in implementing the President's Management Agenda. NASA is leading the government in its implementation of the five government-wide initiatives. NASA received an unqualified audit opinion on FY 2002 financial statements. The vast majority of performance goals have been achieved, furthering each area of NASA's mission. The contents include: 1) NASA Vision and Mission; 2) Management's Discussion and Analysis; 3) Performance; and 4) Financial.

  16. Demonstrating marketing accountability.

    PubMed

    Gombeski, William R; Britt, Jason; Taylor, Jan; Riggs, Karen; Wray, Tanya; Adkins, Wanda; Springate, Suzanne

    2008-01-01

    Pressure on health care marketers to demonstrate effectiveness of their strategies and show their contribution to organizational goals is growing. A seven-tiered model based on the concepts of structure (having the right people, systems), process (doing the right things in the right way), and outcomes (results) is discussed. Examples of measures for each tier are provided and the benefits of using the model as a tool for measuring, organizing, tracking, and communicating appropriate information are provided. The model also provides a framework for helping management understand marketing's value and can serve as a vehicle for demonstrating marketing accountability.

  17. What Is the Value of Public School Accountability?

    ERIC Educational Resources Information Center

    Gunzenhauser, Michael G.; Hyde, Andrea M.

    2007-01-01

    In this review essay, Michael Gunzenhauser and Andrea Hyde consider three recent edited collections that address the potential value of public school accountability policy: Kenneth Sirotnik's Holding Accountability Accountable: What Ought to Matter in Public Education; Martin Carnoy, Richard Elmore, and Leslie Santee Siskin's The New…

  18. Revamping High School Accounting Courses.

    ERIC Educational Resources Information Center

    Bittner, Joseph

    2002-01-01

    Provides ideas for updating accounting courses: convert to semester length; focus on financial reporting/analysis, financial statements, the accounting cycle; turn textbook exercises into practice sets for the accounting cycle; teach about corporate accounting; and address individual line items on financial statements. (SK)

  19. Where Are the Accounting Professors?

    ERIC Educational Resources Information Center

    Chang, Jui-Chin; Sun, Huey-Lian

    2008-01-01

    Accounting education is facing a crisis of shortage of accounting faculty. This study discusses the reasons behind the shortage and offers suggestions to increase the supply of accounting faculty. Our suggestions are as followings. First, educators should begin promoting accounting academia as one of the career choices to undergraduate and…

  20. Accountability and the New Essentials.

    ERIC Educational Resources Information Center

    Dowd, Steven B.

    The current emphasis in education on accountability is tending toward "push-button accountability." The challenge is to evaluate access and retention as well as other educationally relevant goals to define "quality" or "accountability." In higher education, accountability should be proven through assessment and should consist of proof that what…

  1. Familial Confounding of the Association between Maternal Smoking during Pregnancy and Offspring Criminality: A Population-Based Study in Sweden

    PubMed Central

    D’Onofrio, Brian M.; Singh, Amber L.; Iliadou, Anastasia; Lambe, Mats; Hultman, Christina M.; Grann, Martin; Neiderhiser, Jenae M.; Långström, Niklas; Lichtenstein, Paul

    2013-01-01

    Context The association between maternal smoking during pregnancy (SDP) and offspring disruptive behaviors has been well documented, but it is unclear whether exposure to SDP or the effects of factors correlated with SDP account for the increased risk. Objective To test whether the association between SDP and offspring criminal convictions was consistent with a causal connection or due to familial background factors by controlling for measured covariates and using a quasi-experimental approach. Design We used a population-based study of children born in Sweden from 1983–1989 (N=609,372) to examine the association between SDP and offspring criminal convictions, while controlling for measured traits of both parents. We also compared siblings differentially exposed to SDP (N=50,339) to account for unmeasured familial factors that could account for the association. Setting Population-based study of all children born in Sweden from 1983–1989 with information on maternal SDP and offspring criminal convictions, based on national registries collected by the Swedish government. Main Outcome Measures Violent and nonviolent convictions, based on the Swedish National Crime Register, a register with detailed information on all convictions in the country. Results Moderate (HR=2.47, CI=2.34–2.60) and high levels (HR=3.43, CI=3.25–3.63) of maternal SDP was associated with an increased risk for offspring violent convictions, even when controlling for maternal and paternal traits. There was no association between SDP and violent convictions, however, when comparing differentially exposed siblings (HRmoderate=1.02, CI=0.79–1.30; HRhigh=1.03, CI=0.78–1.37). SDP also was associated with nonviolent convictions in the entire population (HRmoderate=1.62, CI=1.58–1.66; HRhigh=1.87, CI=1.82–1.92) and when controlling for covariates. But, there was no association when comparing siblings who were differentially exposed (HRmoderate=0.89, CI=0.78–1.01; HRhigh=0.89, CI=0.78–1

  2. Financial accounting for radiology executives.

    PubMed

    Seidmann, Abraham; Mehta, Tushar

    2005-03-01

    The authors review the role of financial accounting information from the perspective of a radiology executive. They begin by introducing the role of pro forma statements. They discuss the fundamental concepts of accounting, including the matching principle and accrual accounting. The authors then explore the use of financial accounting information in making investment decisions in diagnostic medical imaging. The paper focuses on critically evaluating the benefits and limitations of financial accounting for decision making in a radiology practice.

  3. Automated attendance accounting system

    NASA Technical Reports Server (NTRS)

    Chapman, C. P. (Inventor)

    1973-01-01

    An automated accounting system useful for applying data to a computer from any or all of a multiplicity of data terminals is disclosed. The system essentially includes a preselected number of data terminals which are each adapted to convert data words of decimal form to another form, i.e., binary, usable with the computer. Each data terminal may take the form of a keyboard unit having a number of depressable buttons or switches corresponding to selected data digits and/or function digits. A bank of data buffers, one of which is associated with each data terminal, is provided as a temporary storage. Data from the terminals is applied to the data buffers on a digit by digit basis for transfer via a multiplexer to the computer.

  4. Computerized classified document accountability

    SciTech Connect

    Norris, C.B.; Lewin, R.

    1988-08-01

    This step-by-step procedure was established as a guideline to be used with the Savvy PC Database Program for the accountability of classified documents. Its purpose is to eventually phase out the use of logbooks for classified document tracking. The program runs on an IBM PC or compatible computer using a Bernoulli Box, a Hewlett Packard 71B Bar Code Reader, an IOMEGA Host Adapter Board for creating mirror images of data for backup purposes, and the Disk Operating System (DOS). The DOS batch files ''IN'' and ''OUT'' invoke the Savvy Databases for either entering incoming or outgoing documents. The main files are DESTRUCTION, INLOG, OUTLOG, and NAME-NUMBER. The fields in the files are Adding/Changing, Routing, Destroying, Search-Print by document identification, Search/Print Audit by bar code number, Print Holdings of a person, and Print Inventory of an office.

  5. The microphysics of accountability.

    PubMed

    Wieser, Bernhard

    2011-05-01

    How is it possible to deploy the law to create and perform accountability? To answer this question, I address the argumentative function of the law in order to legitimize genetic medicine. Using interview data, I will in particular elaborate on how medical experts strive to convince interviewing social scientists that their own professional action is above all ethical reproach. For this purpose, medical experts capitalize on the law in specific ways. It is the aim of this article to expound exactly how this happens during qualitative research interviews. The analysis of the interview data is informed by the works of Sheila Jasanoff and Michel Foucault. The former provides an instructive conceptual background for demonstrating how the law serves as an important element of accountability practices. The latter is known for his plea not to understand the law in repressive terms. Accordingly, the law does not prohibit specific medical practices, but in a specific sense it rather makes medical practice socially robust. Based on qualitative analysis of interview data, I conclude that referring to the law allows experts of genetic medicine to evade engaging with ethical and social aspects of their work. The law was rhetorically utilized to bring a discussion on such issues to a communicative closure. For that purpose, the existence of the law was presented as proof that undesirable practices would not be possible and consequently further discussions of the matter would be unnecessary. The law allows medical experts to transfer ethical problems to other places and actors and also to promote their professional interests.

  6. Greenhouse gas accounting and waste management.

    PubMed

    Gentil, Emmanuel; Christensen, Thomas H; Aoustin, Emmanuelle

    2009-11-01

    Accounting of emissions of greenhouse gas (GHG) is a major focus within waste management. This paper analyses and compares the four main types of GHG accounting in waste management including their special features and approaches: the national accounting, with reference to the Intergovernmental Panel on Climate Change (IPCC), the corporate level, as part of the annual reporting on environmental issues and social responsibility, life-cycle assessment (LCA), as an environmental basis for assessing waste management systems and technologies, and finally, the carbon trading methodology, and more specifically, the clean development mechanism (CDM) methodology, introduced to support cost-effective reduction in GHG emissions. These types of GHG accounting, in principle, have a common starting point in technical data on GHG emissions from specific waste technologies and plants, but the limited availability of data and, moreover, the different scopes of the accounting lead to many ways of quantifying emissions and producing the accounts. The importance of transparency in GHG accounting is emphasised regarding waste type, waste composition, time period considered, GHGs included, global warming potential (GWP) assigned to the GHGs, counting of biogenic carbon dioxide, choice of system boundaries, interactions with the energy system, and generic emissions factors. In order to enhance transparency and consistency, a format called the upstream-operating-downstream framework (UOD) is proposed for reporting basic technology-related data regarding GHG issues including a clear distinction between direct emissions from waste management technologies, indirect upstream (use of energy and materials) and indirect downstream (production of energy, delivery of secondary materials) activities.

  7. Both direct and indirect effects account for the pro-inflammatory activity of enteropathogenic mycotoxins on the human intestinal epithelium: Stimulation of interleukin-8 secretion, potentiation of interleukin-1{beta} effect and increase in the transepithelial passage of commensal bacteria

    SciTech Connect

    Maresca, Marc; Yahi, Nouara; Younes-Sakr, Lama; Boyron, Marilyn; Caporiccio, Bertrand; Fantini, Jacques

    2008-04-01

    Mycotoxins are fungal secondary metabolites responsible of food-mediated intoxication in animals and humans. Deoxynivalenol, ochratoxin A and patulin are the best known enteropathogenic mycotoxins able to alter intestinal functions resulting in malnutrition, diarrhea, vomiting and intestinal inflammation in vivo. Although their effects on intestinal barrier and transport activities have been extensively characterized, the mechanisms responsible for their pro-inflammatory effect are still poorly understood. Here we investigated if mycotoxin-induced intestinal inflammation results from a direct and/or indirect pro-inflammatory activity of these mycotoxins on human intestinal epithelial cells, using differentiated Caco-2 cells as model and interleukin 8 (IL-8) as an indicator of intestinal inflammation. Deoxynivalenol was the only mycotoxin able to directly increase IL-8 secretion (10- to 15-fold increase). We also investigated if these mycotoxins could indirectly stimulate IL-8 secretion through: (i) a modulation of the action of pro-inflammatory molecules such as the interleukin-1beta (IL-1{beta}), and/or (ii) an increase in the transepithelial passage of non-invasive commensal Escherichia coli. We found that deoxynivalenol, ochratoxin A and patulin all potentiated the effect of IL-1{beta} on IL-8 secretion (ranging from 35% to 138% increase) and increased the transepithelial passage of commensal bacteria (ranging from 12- to 1544-fold increase). In addition to potentially exacerbate established intestinal inflammation, these mycotoxins may thus participate in the induction of sepsis and intestinal inflammation in vivo. Taken together, our results suggest that the pro-inflammatory activity of enteropathogenic mycotoxins is mediated by both direct and indirect effects.

  8. Accounting Issues: An Essay Series. Part II--Accounts Receivable

    ERIC Educational Resources Information Center

    Laux, Judith A.

    2007-01-01

    This is the second in a series of articles designed to help academics refocus the introductory accounting course on the theoretical underpinnings of accounting. Intended as a supplement for the principles course, this article connects the asset Accounts Receivable to the essential theoretical constructs, discusses the inherent tradeoffs and…

  9. Solving Accounting Problems: Differences between Accounting Experts and Novices.

    ERIC Educational Resources Information Center

    Marshall, P. Douglas

    2002-01-01

    Performance of 90 accounting experts (faculty and practitioners) and 60 novices (senior accounting majors) was compared. Experts applied more accounting principles to solving problems. There were no differences in types of principles applied and no correlation between (1) principles applied and number of breadth comments or (2) importance placed…

  10. Keeping Public Officials Accountable through Dialogue: Resolving the Accountability Paradox.

    ERIC Educational Resources Information Center

    Roberts, Nancy C.

    2002-01-01

    Discusses Harmon's Accountability Paradox in relation to the accountability of public officials. Promotes the use of dialogue because its advantage outweighs its cost as a mechanism of accountability when officials confront problems that defy definition and solution and when traditional solution methods have failed. (Contains 54 references.) (JOW)

  11. 18 CFR 367.9040 - Account 904, Uncollectible accounts.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 18 Conservation of Power and Water Resources 1 2012-04-01 2012-04-01 false Account 904, Uncollectible accounts. 367.9040 Section 367.9040 Conservation of Power and Water Resources FEDERAL ENERGY..., FEDERAL POWER ACT AND NATURAL GAS ACT UNIFORM SYSTEM OF ACCOUNTS FOR CENTRALIZED SERVICE COMPANIES...

  12. 18 CFR 367.9040 - Account 904, Uncollectible accounts.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 18 Conservation of Power and Water Resources 1 2013-04-01 2013-04-01 false Account 904, Uncollectible accounts. 367.9040 Section 367.9040 Conservation of Power and Water Resources FEDERAL ENERGY..., FEDERAL POWER ACT AND NATURAL GAS ACT UNIFORM SYSTEM OF ACCOUNTS FOR CENTRALIZED SERVICE COMPANIES...

  13. 18 CFR 367.1420 - Account 142, Customer accounts receivable.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 18 Conservation of Power and Water Resources 1 2012-04-01 2012-04-01 false Account 142, Customer accounts receivable. 367.1420 Section 367.1420 Conservation of Power and Water Resources FEDERAL ENERGY..., FEDERAL POWER ACT AND NATURAL GAS ACT UNIFORM SYSTEM OF ACCOUNTS FOR CENTRALIZED SERVICE COMPANIES...

  14. 18 CFR 367.9040 - Account 904, Uncollectible accounts.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 18 Conservation of Power and Water Resources 1 2014-04-01 2014-04-01 false Account 904, Uncollectible accounts. 367.9040 Section 367.9040 Conservation of Power and Water Resources FEDERAL ENERGY..., FEDERAL POWER ACT AND NATURAL GAS ACT UNIFORM SYSTEM OF ACCOUNTS FOR CENTRALIZED SERVICE COMPANIES...

  15. 18 CFR 367.1430 - Account 143, Other accounts receivable.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 18 Conservation of Power and Water Resources 1 2011-04-01 2011-04-01 false Account 143, Other accounts receivable. 367.1430 Section 367.1430 Conservation of Power and Water Resources FEDERAL ENERGY..., FEDERAL POWER ACT AND NATURAL GAS ACT UNIFORM SYSTEM OF ACCOUNTS FOR CENTRALIZED SERVICE COMPANIES...

  16. 18 CFR 367.1840 - Account 184, Clearing accounts.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Account 184, Clearing accounts. 367.1840 Section 367.1840 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY... POWER ACT AND NATURAL GAS ACT UNIFORM SYSTEM OF ACCOUNTS FOR CENTRALIZED SERVICE COMPANIES SUBJECT...

  17. 18 CFR 367.9040 - Account 904, Uncollectible accounts.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 18 Conservation of Power and Water Resources 1 2011-04-01 2011-04-01 false Account 904, Uncollectible accounts. 367.9040 Section 367.9040 Conservation of Power and Water Resources FEDERAL ENERGY..., FEDERAL POWER ACT AND NATURAL GAS ACT UNIFORM SYSTEM OF ACCOUNTS FOR CENTRALIZED SERVICE COMPANIES...

  18. 18 CFR 367.1840 - Account 184, Clearing accounts.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 18 Conservation of Power and Water Resources 1 2012-04-01 2012-04-01 false Account 184, Clearing accounts. 367.1840 Section 367.1840 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY... POWER ACT AND NATURAL GAS ACT UNIFORM SYSTEM OF ACCOUNTS FOR CENTRALIZED SERVICE COMPANIES SUBJECT...

  19. 18 CFR 367.1430 - Account 143, Other accounts receivable.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 18 Conservation of Power and Water Resources 1 2013-04-01 2013-04-01 false Account 143, Other accounts receivable. 367.1430 Section 367.1430 Conservation of Power and Water Resources FEDERAL ENERGY..., FEDERAL POWER ACT AND NATURAL GAS ACT UNIFORM SYSTEM OF ACCOUNTS FOR CENTRALIZED SERVICE COMPANIES...

  20. 18 CFR 367.1840 - Account 184, Clearing accounts.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 18 Conservation of Power and Water Resources 1 2013-04-01 2013-04-01 false Account 184, Clearing accounts. 367.1840 Section 367.1840 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY... POWER ACT AND NATURAL GAS ACT UNIFORM SYSTEM OF ACCOUNTS FOR CENTRALIZED SERVICE COMPANIES SUBJECT...

  1. 18 CFR 367.1420 - Account 142, Customer accounts receivable.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 18 Conservation of Power and Water Resources 1 2014-04-01 2014-04-01 false Account 142, Customer accounts receivable. 367.1420 Section 367.1420 Conservation of Power and Water Resources FEDERAL ENERGY..., FEDERAL POWER ACT AND NATURAL GAS ACT UNIFORM SYSTEM OF ACCOUNTS FOR CENTRALIZED SERVICE COMPANIES...

  2. 18 CFR 367.1430 - Account 143, Other accounts receivable.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Account 143, Other accounts receivable. 367.1430 Section 367.1430 Conservation of Power and Water Resources FEDERAL ENERGY..., FEDERAL POWER ACT AND NATURAL GAS ACT UNIFORM SYSTEM OF ACCOUNTS FOR CENTRALIZED SERVICE COMPANIES...

  3. 18 CFR 367.1420 - Account 142, Customer accounts receivable.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 18 Conservation of Power and Water Resources 1 2013-04-01 2013-04-01 false Account 142, Customer accounts receivable. 367.1420 Section 367.1420 Conservation of Power and Water Resources FEDERAL ENERGY..., FEDERAL POWER ACT AND NATURAL GAS ACT UNIFORM SYSTEM OF ACCOUNTS FOR CENTRALIZED SERVICE COMPANIES...

  4. 18 CFR 367.1420 - Account 142, Customer accounts receivable.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Account 142, Customer accounts receivable. 367.1420 Section 367.1420 Conservation of Power and Water Resources FEDERAL ENERGY..., FEDERAL POWER ACT AND NATURAL GAS ACT UNIFORM SYSTEM OF ACCOUNTS FOR CENTRALIZED SERVICE COMPANIES...

  5. 18 CFR 367.1430 - Account 143, Other accounts receivable.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 18 Conservation of Power and Water Resources 1 2014-04-01 2014-04-01 false Account 143, Other accounts receivable. 367.1430 Section 367.1430 Conservation of Power and Water Resources FEDERAL ENERGY..., FEDERAL POWER ACT AND NATURAL GAS ACT UNIFORM SYSTEM OF ACCOUNTS FOR CENTRALIZED SERVICE COMPANIES...

  6. 18 CFR 367.1430 - Account 143, Other accounts receivable.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 18 Conservation of Power and Water Resources 1 2012-04-01 2012-04-01 false Account 143, Other accounts receivable. 367.1430 Section 367.1430 Conservation of Power and Water Resources FEDERAL ENERGY..., FEDERAL POWER ACT AND NATURAL GAS ACT UNIFORM SYSTEM OF ACCOUNTS FOR CENTRALIZED SERVICE COMPANIES...

  7. 18 CFR 367.9040 - Account 904, Uncollectible accounts.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Account 904, Uncollectible accounts. 367.9040 Section 367.9040 Conservation of Power and Water Resources FEDERAL ENERGY..., FEDERAL POWER ACT AND NATURAL GAS ACT UNIFORM SYSTEM OF ACCOUNTS FOR CENTRALIZED SERVICE COMPANIES...

  8. The siting record: An account of the programs of federal agencies and events that have led to the selection of a potential site for a geologic respository for high-level radioactive waste

    SciTech Connect

    Lomenick, T.F.

    1996-03-01

    This record of siting a geologic repository for high-level radioactive wastes (HLW) and spent fuel describes the many investigations that culminated on December 22, 1987 in the designation of Yucca Mountain (YM), as the site to undergo detailed geologic characterization. It recounts the important issues and events that have been instrumental in shaping the course of siting over the last three and one half decades. In this long task, which was initiated in 1954, more than 60 regions, areas, or sites involving nine different rock types have been investigated. This effort became sharply focused in 1983 with the identification of nine potentially suitable sites for the first repository. From these nine sites, five were subsequently nominated by the U.S. Department of Energy (DOE) as suitable for characterization and then, in 1986, as required by the Nuclear Waste Policy Act of 1982 (NWPA), three of these five were recommended to the President as candidates for site characterization. President Reagan approved the recommendation on May 28, 1986. DOE was preparing site characterization plans for the three candidate sites, namely Deaf Smith County, Texas; Hanford Site, Washington; and YM. As a consequence of the 1987 Amendment to the NWPA, only the latter was authorized to undergo detailed characterization. A final Site Characterization Plan for Yucca Mountain was published in 1988. Prior to 1954, there was no program for the siting of disposal facilities for high-level waste (HLW). In the 1940s and 1950s, the volume of waste, which was small and which resulted entirely from military weapons and research programs, was stored as a liquid in large steel tanks buried at geographically remote government installations principally in Washington and Tennessee.

  9. NASA Accountability Report

    NASA Technical Reports Server (NTRS)

    1997-01-01

    NASA is piloting fiscal year (FY) 1997 Accountability Reports, which streamline and upgrade reporting to Congress and the public. The document presents statements by the NASA administrator, and the Chief Financial Officer, followed by an overview of NASA's organizational structure and the planning and budgeting process. The performance of NASA in four strategic enterprises is reviewed: (1) Space Science, (2) Mission to Planet Earth, (3) Human Exploration and Development of Space, and (4) Aeronautics and Space Transportation Technology. Those areas which support the strategic enterprises are also reviewed in a section called Crosscutting Processes. For each of the four enterprises, there is discussion about the long term goals, the short term objectives and the accomplishments during FY 1997. The Crosscutting Processes section reviews issues and accomplishments relating to human resources, procurement, information technology, physical resources, financial management, small and disadvantaged businesses, and policy and plans. Following the discussion about the individual areas is Management's Discussion and Analysis, about NASA's financial statements. This is followed by a report by an independent commercial auditor and the financial statements.

  10. Spills, drills, and accountability

    SciTech Connect

    1993-12-31

    NRDC seeks preventive approaches to oil pollution on U.S. coasts. The recent oil spills in Spain and Scotland have highlighted a fact too easy to forget in a society that uses petroleum every minute of every day: oil is profoundly toxic. One tiny drop on a bald eagle`s egg has been known to kill the embryo inside. Every activity involving oil-drilling for it, piping it, shipping it-poses risks that must be taken with utmost caution. Moreover, oil production is highly polluting. It emits substantial air pollution, such as nitrogen oxides that can form smog and acid rain. The wells bring up great quantities of toxic waste: solids, liquids and sludges often contaminated by oil, toxic metals, or even radioactivity. This article examines the following topics focusing on oil pollution control and prevention in coastal regions of the USA: alternate energy sources and accountability of pollutor; ban on offshore drilling as exemplified by the energy policy act; tanker free zones; accurate damage evaluations. Policy of the National Resource Defence Council is articulated.

  11. Holding services to account

    PubMed Central

    Clegg, J

    2008-01-01

    Background Recently, the frequency of audit inspections of health services for people with intellectual disability (ID) in the UK has increased, from occasional inquiries to a systematic audit of all services. From 2008, a process of continuous audit ‘surveillance’ of specialist health services is to be introduced. Similar regimes of inspection are in place for social care services. Aim To explore the conceptual positions which inform audit, through detailed examination of the investigation into the learning disability service at Sutton and Merton. Findings Audit is distinct from evaluation because it neither provides opportunities for service staff to give an account of their work nor represents a search for knowledge. Audit investigates adherence to government policy. In ID, audits measure aspirations derived from normalisation, despite research showing that some of these aspirations have not been achieved by any service. As audit consumes significant public resource, it is questionable whether the dominant finding of the Healthcare Commission's investigation into Sutton and Merton, that the ID service was chronically under-funded, represents value for money. Discussion and conclusions While basic checks on minimum standards will always be necessary, service excellence requires not audit but research-driven evaluation. Audits inhibit rather than open-up debate about improving support to people with ID. They impose an ideology, squander resource, and demoralise carers and staff. Evaluations challenge the implicit management-versus-professional binary enacted by audit, and can inform new care systems which make effective use of all those engaged with people with ID. PMID:18498335

  12. Accountability report - fiscal year 1997

    SciTech Connect

    1998-04-01

    This document contains the US NRC`s accountability report for fiscal year 1997. Topics include uses of funds, financial condition, program performance, management accountability, and the audited financial statement.

  13. Development of histopathological indices in the digestive gland and gonad of mussels: integration with contamination levels and effects of confounding factors.

    PubMed

    Cuevas, Nagore; Zorita, Izaskun; Costa, Pedro M; Franco, Javier; Larreta, Joana

    2015-05-01

    Bivalve histopathology has become an important tool in aquatic toxicology, having been implemented in many biomonitoring programmes worldwide. However, there are various gaps in the knowledge of many sentinel organisms and the interference of confounding factors. This work aimed (i) to develop a detailed semi-quantitative histopathological index of the digestive gland and gonad of the Mytilus galloprovincialis mussel collected from five sites contaminated with distinct patterns of organic and inorganic toxicants along the Basque coast (SE Bay of Biscay) and (ii) to investigate whether seasonal variability and parasitosis act as confounding factors. A total of twenty-three histopathological alterations were analysed in the digestive gland and gonad following a weighed condition index approach. The alterations were integrated into a single value for a better understanding of the mussels' health status. The digestive gland was consistently more damaged than the gonad. Mussels from the most impacted sites endured the most significant deleterious effects showing inflammation-related alterations together with digestive tubule atrophy and necrosis. Neoplastic diseases were scarce, with only a few cases of fibromas (benign neoplasia). In contrast, in moderately or little impacted sites, contamination levels did not cause significant tissue damage. However, parasites contributed to overestimating the values of histopathological indices (i.e. more severe tissue damage) in mussels from little impacted sites, whilst the opposite occurred in mussels from highly polluted sites. Accordingly, inter-site differences were more pronounced in autumn when natural physiological responses of advanced maturation stages did not interfere in the histological response. In conclusion, although seasonal variability and parasitosis mask the response of histopathological indices, this biomonitoring approach may provide good sensitivity for assessing the health status of mussels if fluctuations

  14. A method for improving predictive modeling by taking into account lag time: Example of selenium bioaccumulation in a flowing system.

    PubMed

    Beckon, William N

    2016-07-01

    For bioaccumulative substances, efforts to predict concentrations in organisms at upper trophic levels, based on measurements of environmental exposure, have been confounded by the appreciable but hitherto unknown amount of time it may take for bioaccumulation to occur through various pathways and across several trophic transfers. The study summarized here demonstrates an objective method of estimating this lag time by testing a large array of potential lag times for selenium bioaccumulation, selecting the lag that provides the best regression between environmental exposure (concentration in ambient water) and concentration in the tissue of the target organism. Bioaccumulation lag is generally greater for organisms at higher trophic levels, reaching times of more than a year in piscivorous fish. Predictive modeling of bioaccumulation is improved appreciably by taking into account this lag. More generally, the method demonstrated here may improve the accuracy of predictive modeling in a wide variety of other cause-effect relationships in which lag time is substantial but inadequately known, in disciplines as diverse as climatology (e.g., the effect of greenhouse gases on sea levels) and economics (e.g., the effects of fiscal stimulus on employment).

  15. A method for improving predictive modeling by taking into account lag time: Example of selenium bioaccumulation in a flowing system.

    PubMed

    Beckon, William N

    2016-07-01

    For bioaccumulative substances, efforts to predict concentrations in organisms at upper trophic levels, based on measurements of environmental exposure, have been confounded by the appreciable but hitherto unknown amount of time it may take for bioaccumulation to occur through various pathways and across several trophic transfers. The study summarized here demonstrates an objective method of estimating this lag time by testing a large array of potential lag times for selenium bioaccumulation, selecting the lag that provides the best regression between environmental exposure (concentration in ambient water) and concentration in the tissue of the target organism. Bioaccumulation lag is generally greater for organisms at higher trophic levels, reaching times of more than a year in piscivorous fish. Predictive modeling of bioaccumulation is improved appreciably by taking into account this lag. More generally, the method demonstrated here may improve the accuracy of predictive modeling in a wide variety of other cause-effect relationships in which lag time is substantial but inadequately known, in disciplines as diverse as climatology (e.g., the effect of greenhouse gases on sea levels) and economics (e.g., the effects of fiscal stimulus on employment). PMID:27149556

  16. Gene therapy restores vision in rd1 mice after removal of a confounding mutation in Gpr179

    PubMed Central

    Nishiguchi, Koji M.; Carvalho, Livia S.; Rizzi, Matteo; Powell, Kate; Holthaus, Sophia-Martha kleine; Azam, Selina A.; Duran, Yanai; Ribeiro, Joana; Luhmann, Ulrich F. O.; Bainbridge, James W. B.; Smith, Alexander J.; Ali, Robin R.

    2015-01-01

    The rd1 mouse with a mutation in the Pde6b gene was the first strain of mice identified with a retinal degeneration. However, AAV-mediated gene supplementation of rd1 mice only results in structural preservation of photoreceptors, and restoration of the photoreceptor-mediated a-wave, but not in restoration of the bipolar cell-mediated b-wave. Here we show that a mutation in Gpr179 prevents the full restoration of vision in rd1 mice. Backcrossing rd1 with C57BL6 mice reveals the complete lack of b-wave in a subset of mice, consistent with an autosomal recessive Mendelian inheritance pattern. We identify a mutation in the Gpr179 gene, which encodes for a G-protein coupled receptor localized to the dendrites of ON-bipolar cells. Gene replacement in rd1 mice that are devoid of the mutation in Gpr179 successfully restores the function of both photoreceptors and bipolar cells, which is maintained for up to 13 months. Our discovery may explain the failure of previous gene therapy attempts in rd1 mice, and we propose that Grp179 mutation status should be taken into account in future studies involving rd1 mice. PMID:25613321

  17. Batch-to-batch pharmacokinetic variability confounds current bioequivalence regulations: A dry powder inhaler randomized clinical trial.

    PubMed

    Burmeister Getz, E; Carroll, K J; Jones, B; Benet, L Z

    2016-09-01

    Current pharmacokinetic (PK) bioequivalence guidelines do not account for batch-to-batch variability in study design or analysis. Here we evaluate the magnitude of batch-to-batch PK variability for Advair Diskus 100/50. Single doses of fluticasone propionate and salmeterol combinations were administered by oral inhalation to healthy subjects in a randomized clinical crossover study comparing three different batches purchased from the market, with one batch replicated across two treatment periods. All pairwise comparisons between different batches failed the PK bioequivalence statistical test, demonstrating substantial PK differences between batches that were large enough to demonstrate bio-inequivalence in some cases. In contrast, between-replicate PK bioequivalence was demonstrated for the replicated batch. Between-batch variance was ∼40-70% of the estimated residual error. This large additional source of variability necessitates re-evaluation of bioequivalence assessment criteria to yield a result that is both generalizable and consistent with the principles of type I and type II error rate control.

  18. Fasting substrate oxidation at rest assessed by indirect calorimetry: is prior dietary macronutrient level and composition a confounder?

    PubMed

    Miles-Chan, J L; Dulloo, A G; Schutz, Y

    2015-07-01

    Indirect calorimetry, the measurement of O₂ consumption and CO₂ production, constitutes an invaluable tool as the most common method for analyzing whole-body energy expenditure, and also provides an index of the nature of macronutrient substrate oxidation--namely, carbohydrate (CHO) versus fat oxidation. The latter constitutes a key etiological factor in obesity as this condition can only develop when total fat oxidation is chronically lower than total exogenous fat intake. The standardization of indirect calorimetry measurements is essential for accurately tracking the relative proportion of energy expenditure derived from CHO and fat oxidation. Here we analyze literature data to show that the average fasting respiratory quotient typically shifts from approximately 0.80 to 0.90 (indicating a doubling of resting CHO oxidation) in response to a switch in dietary CHO intake (as % energy) from 30 to 60%. This underscores the importance of taking into account dietary macronutrient composition prior to indirect calorimetry studies in the interpretation of data on substrate utilization and oxidation.

  19. 'Bigger data' on scale-dependent effects of invasive species on biodiversity cannot overcome confounded analyses: a comment on Stohlgren & Rejmánek (2014).

    PubMed

    Chase, Jonathan M; Powell, Kristin I; Knight, Tiffany M

    2015-08-01

    A recent study by Stohlgren & Rejmánek (SR: Stohlgren TJ, Rejmánek M. 2014 Biol. Lett. 10. (doi:10.1098/rsbl.2013.0939)) purported to test the generality of a recent finding of scale-dependent effects of invasive plants on native diversity; dominant invasive plants decreased the intercept and increased the slope of the species-area relationship. SR (2014) find little correlation between invasive species cover and the slopes and intercepts of SARs across a diversity of sites. We show that the analyses of SR (2014) are inappropriate because of confounding causality.

  20. 'Bigger data' on scale-dependent effects of invasive species on biodiversity cannot overcome confounded analyses: a comment on Stohlgren & Rejmánek (2014).

    PubMed

    Chase, Jonathan M; Powell, Kristin I; Knight, Tiffany M

    2015-08-01

    A recent study by Stohlgren & Rejmánek (SR: Stohlgren TJ, Rejmánek M. 2014 Biol. Lett. 10. (doi:10.1098/rsbl.2013.0939)) purported to test the generality of a recent finding of scale-dependent effects of invasive plants on native diversity; dominant invasive plants decreased the intercept and increased the slope of the species-area relationship. SR (2014) find little correlation between invasive species cover and the slopes and intercepts of SARs across a diversity of sites. We show that the analyses of SR (2014) are inappropriate because of confounding causality. PMID:26246332

  1. How to Professionalize Accounting Programs

    ERIC Educational Resources Information Center

    Allyn, Robert G.

    1977-01-01

    The author, a certified public accountant on the State Board for Public Accountancy of New York, Discusses education and training programs to "professionalize" accounting, particularly the need for innovative learning modules that integrate the traditional sequence of courses in baccalaureate programs. (MF)

  2. Standardized Testing and School Accountability

    ERIC Educational Resources Information Center

    Wiliam, Dylan

    2010-01-01

    This article explores the use of standardized tests to hold schools accountable. The history of testing for accountability is reviewed, and it is shown that currently between-school differences account for less than 10% of the variance in student scores, in part because the progress of individuals is small compared to the spread of achievement…

  3. Vocational Accounting and Computing Programs.

    ERIC Educational Resources Information Center

    Avani, Nathan T.

    1986-01-01

    Describes an "Accounting and Computing" program in Michigan that emphasizes computerized accounting procedures. This article describes the program curriculum and duty areas (such as handling accounts receivable), presents a list of sample tasks in each duty area, and specifies components of each task. Computer equipment necessary for this program…

  4. Symphony Time Accounting Resource (STAR)

    SciTech Connect

    Newfield, S.E.; Booth, J.W.; Redman, D.L.

    1986-05-01

    The Symphony Time Accounting Resource, a new time accounting system, that can be run on personal computers instead of computer mainframes is described. This new system is useful for organizations that do work under several job order numbers and/or accounting codes and could also be adapted for use by organizations on the recharge system. 1 fig., 2 tabs.

  5. An Accounting Writing Proficiency Survey

    ERIC Educational Resources Information Center

    Firch, Tim; Campbell, Annhenrie; Filling, Steven; Lindsay, David H.

    2011-01-01

    Although there has been much discussion about improving college student writing with college-level courses, little is known about how accounting programs, in particular, are addressing the writing proficiency challenge. This study surveys the 852 accounting programs in the United States to identify the frequency and types of accounting writing…

  6. Mastering the Vocabulary of Accounting.

    ERIC Educational Resources Information Center

    Tischler, Helene

    Developed for use by students in an introductory accounting course, these learning modules deal with mastering the vocabulary of accounting. Focus of the modules is on vocabulary appearing in the first six chapters of the text, "Accounting Principles" by Niswonger and Fess. Covered in the individual modules are the following topics: discovering…

  7. 46 CFR Sec. 5 - Accounting.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 8 2010-10-01 2010-10-01 false Accounting. Sec. 5 Section 5 Shipping MARITIME... Sec. 5 Accounting. The General Agent shall record the amounts of compensation paid from the NSA... Accounting Office, at which time the Maritime Administration will take custody of the records....

  8. Contamination of Current Accountability Systems

    ERIC Educational Resources Information Center

    McGill-Franzen, Anne; Allington, Richard

    2006-01-01

    As public employees, educators should expect to be held accountable for their use of public funds. Nonetheless, the various state governments and now the U.S. Department of Education have implemented high-stakes achievement testing as the nearly singular approach to accountability. While these accountability efforts vary in a number of ways,…

  9. 12 CFR 390.281 - Account.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 5 2014-01-01 2014-01-01 false Account. 390.281 Section 390.281 Banks and... Associations § 390.281 Account. The term account means any savings account, demand account, certificate account, tax and loan account, note account, United States Treasury general account or United States...

  10. 12 CFR 161.2 - Account.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 1 2014-01-01 2014-01-01 false Account. 161.2 Section 161.2 Banks and Banking... ASSOCIATIONS § 161.2 Account. The term account means any savings account, demand account, certificate account, tax and loan account, note account, United States Treasury general account or United States...

  11. 12 CFR 561.2 - Account.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 6 2014-01-01 2012-01-01 true Account. 561.2 Section 561.2 Banks and Banking... SAVINGS ASSOCIATIONS § 561.2 Account. The term account means any savings account, demand account, certificate account, tax and loan account, note account, United States Treasury general account or...

  12. 12 CFR 161.2 - Account.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 1 2012-01-01 2012-01-01 false Account. 161.2 Section 161.2 Banks and Banking... ASSOCIATIONS § 161.2 Account. The term account means any savings account, demand account, certificate account, tax and loan account, note account, United States Treasury general account or United States...

  13. 12 CFR 561.2 - Account.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 6 2013-01-01 2012-01-01 true Account. 561.2 Section 561.2 Banks and Banking... SAVINGS ASSOCIATIONS § 561.2 Account. The term account means any savings account, demand account, certificate account, tax and loan account, note account, United States Treasury general account or...

  14. 12 CFR 561.2 - Account.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 5 2010-01-01 2010-01-01 false Account. 561.2 Section 561.2 Banks and Banking... SAVINGS ASSOCIATIONS § 561.2 Account. The term account means any savings account, demand account, certificate account, tax and loan account, note account, United States Treasury general account or...

  15. 12 CFR 161.2 - Account.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 1 2013-01-01 2013-01-01 false Account. 161.2 Section 161.2 Banks and Banking... ASSOCIATIONS § 161.2 Account. The term account means any savings account, demand account, certificate account, tax and loan account, note account, United States Treasury general account or United States...

  16. 12 CFR 561.2 - Account.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 5 2011-01-01 2011-01-01 false Account. 561.2 Section 561.2 Banks and Banking... SAVINGS ASSOCIATIONS § 561.2 Account. The term account means any savings account, demand account, certificate account, tax and loan account, note account, United States Treasury general account or...

  17. 12 CFR 390.281 - Account.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 5 2013-01-01 2013-01-01 false Account. 390.281 Section 390.281 Banks and... Associations § 390.281 Account. The term account means any savings account, demand account, certificate account, tax and loan account, note account, United States Treasury general account or United States...

  18. 12 CFR 390.281 - Account.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 5 2012-01-01 2012-01-01 false Account. 390.281 Section 390.281 Banks and... Associations § 390.281 Account. The term account means any savings account, demand account, certificate account, tax and loan account, note account, United States Treasury general account or United States...

  19. 12 CFR 561.2 - Account.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 6 2012-01-01 2012-01-01 false Account. 561.2 Section 561.2 Banks and Banking... SAVINGS ASSOCIATIONS § 561.2 Account. The term account means any savings account, demand account, certificate account, tax and loan account, note account, United States Treasury general account or...

  20. Analysis of the effects of microbiome-related confounding factors on the reproducibility of the volatolomic test.

    PubMed

    Leja, Marcis; Amal, Haitham; Lasina, Ieva; Skapars, Roberts; Sivins, Armands; Ancans, Guntis; Tolmanis, Ivars; Vanags, Aigars; Kupcinskas, Juozas; Ramonaite, Rima; Khatib, Salam; Bdarneh, Shifaa; Natour, Rasha; Ashkar, Areen; Haick, Hossam

    2016-01-01

    Volatile organic compound (VOC) testing in breath has potential in gastric cancer (GC) detection. Our objective was to assess the reproducibility of VOCs in GC, and the effects of conditions modifying gut microbiome on the test results. Ten patients with GC were sampled for VOC over three consecutive days; 17 patients were sampled before and after H. pylori eradication therapy combined with a yeast probiotic; 61 patients were sampled before and after bowel cleansing (interventions affecting the microbiome). The samples were analyzed by: (1) gas chromatography linked to mass spectrometry (GC-MS), applying the non-parametric Wilcoxon test (level of significance p  <  0.05); (2) by cross-reactive nanoarrays combined with pattern recognition. Discriminant function analysis (DFA) was used to build the classification models; and leave-one-out cross-validation analysis was used to classify the findings. Exhaled VOCs profiles were stable for GC patients over a three day period. Alpha pinene (p  =  0.028) and ethyl acetate (p  =  0.030) increased after the antibiotic containing eradication regimen; acetone (p  =  0.0001) increased following bowel cleansing prior to colonoscopy. We further hypothesize that S. boulardii given with the standard eradication regimen to re-establish the gut microbiome was the source for long-term ethyl acetate production. Differences between the initial and the follow-up sample were also revealed in the DFA analysis of the sensor data. VOC measurement results are well-reproducible in GC patients indicating a useful basis for potential disease diagnostics. However, interventions with a potential effect on the gut microbiome may have an effect upon the VOC results, and therefore should be considered for diagnostic accuracy. PMID:27341527

  1. 77 FR 43542 - Cost Accounting Standards: Cost Accounting Standards 412 and 413-Cost Accounting Standards...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-25

    ... Harmonization Rule. The final rule was published at 76 FR 81296 on December 27, 2011. Generally, the technical... BUDGET Office of Federal Procurement Policy 48 CFR Part 9904 Cost Accounting Standards: Cost Accounting Standards 412 and 413--Cost Accounting Standards Pension Harmonization Rule AGENCY: Cost...

  2. Analytic Strategies to Adjust Confounding Using Exposure Propensity Scores and Disease Risk Scores: Nonsteroidal Antiinflammatory Drugs (NSAID) and Short-term Mortality in the Elderly

    PubMed Central

    Stürmer, Til; Schneeweiss, Sebastian; Brookhart, M. Alan; Rothman, Kenneth J; Avorn, Jerry; Glynn, Robert J

    2006-01-01

    Little is known about optimal application and behavior of exposure propensity scores (EPS) in small studies. Based on a cohort of 103,133 elderly Medicaid beneficiaries, the effect of nonsteroidal anti-inflammatory drug (NSAID) use on 1-year all-cause mortality was assessed based on the assumption that there is no protective effect, and the preponderance of any observed effect would be confounded. To study the comparative behavior of EPS, disease risk scores (DRS), and ‘traditional’ disease models, we randomly re-sampled 1,000 subcohorts of 10,000, 1,000 and 500 people. The number of variables was limited in disease models, but not EPS and DRS. Estimated EPS were used to adjust for confounding by matching, inverse probability of treatment weighting (IPTW), stratification, and modeling. The crude rate ratio (RR) of death for NSAID users was 0.68. ‘Traditional’ adjustment resulted in a RR of 0.80 (95% confidence interval:0.77–0.84). The RR closest to 1 was achieved by IPTW (0.85;0.82–0.88). With decreasing study size, estimates remained further from the null, which was most pronounced for IPTW (N=500: RR=0.72;0.26–1.68). In this setting, analytic strategies using EPS or DRS were not generally superior to ‘traditional’. Various ways to use EPS and DRS behaved differently with smaller study size. PMID:15840622

  3. fMRI measurements of amygdala activation are confounded by stimulus correlated signal fluctuation in nearby veins draining distant brain regions

    PubMed Central

    Boubela, Roland N.; Kalcher, Klaudius; Huf, Wolfgang; Seidel, Eva-Maria; Derntl, Birgit; Pezawas, Lukas; Našel, Christian; Moser, Ewald

    2015-01-01

    Imaging the amygdala with functional MRI is confounded by multiple averse factors, notably signal dropouts due to magnetic inhomogeneity and low signal-to-noise ratio, making it difficult to obtain consistent activation patterns in this region. However, even when consistent signal changes are identified, they are likely to be due to nearby vessels, most notably the basal vein of rosenthal (BVR). Using an accelerated fMRI sequence with a high temporal resolution (TR = 333 ms) combined with susceptibility-weighted imaging, we show how signal changes in the amygdala region can be related to a venous origin. This finding is confirmed here in both a conventional fMRI dataset (TR = 2000 ms) as well as in information of meta-analyses, implying that “amygdala activations” reported in typical fMRI studies are likely confounded by signals originating in the BVR rather than in the amygdala itself, thus raising concerns about many conclusions on the functioning of the amygdala that rely on fMRI evidence alone. PMID:25994551

  4. An improved framework for confound regression and filtering for control of motion artifact in the preprocessing of resting-state functional connectivity data.

    PubMed

    Satterthwaite, Theodore D; Elliott, Mark A; Gerraty, Raphael T; Ruparel, Kosha; Loughead, James; Calkins, Monica E; Eickhoff, Simon B; Hakonarson, Hakon; Gur, Ruben C; Gur, Raquel E; Wolf, Daniel H

    2013-01-01

    Several recent reports in large, independent samples have demonstrated the influence of motion artifact on resting-state functional connectivity MRI (rsfc-MRI). Standard rsfc-MRI preprocessing typically includes regression of confounding signals and band-pass filtering. However, substantial heterogeneity exists in how these techniques are implemented across studies, and no prior study has examined the effect of differing approaches for the control of motion-induced artifacts. To better understand how in-scanner head motion affects rsfc-MRI data, we describe the spatial, temporal, and spectral characteristics of motion artifacts in a sample of 348 adolescents. Analyses utilize a novel approach for describing head motion on a voxelwise basis. Next, we systematically evaluate the efficacy of a range of confound regression and filtering techniques for the control of motion-induced artifacts. Results reveal that the effectiveness of preprocessing procedures on the control of motion is heterogeneous, and that improved preprocessing provides a substantial benefit beyond typical procedures. These results demonstrate that the effect of motion on rsfc-MRI can be substantially attenuated through improved preprocessing procedures, but not completely removed.

  5. A procedural, pragmatist account of ethical objectivity.

    PubMed

    Roth, Amanda

    2013-06-01

    This article offers a procedural, pragmatist account of objectivity in the domain of the good that is inspired by pragmatic and feminist critiques of objectivity in philosophy of science and epistemology. I begin by asking first what we want to capture--or ought to want to capture--with a notion of ethical objectivity and in answer to this question I identify four "points" to ethical objectivity: undergirding the possibility of mistakenness, making genuine disagreement possible, making sense of our appreciation of the ethical perspectives of others, and making possible a sense of ethical improvement or learning. I then lay out a process-based account of objectivity in ethics that makes good on the four points I have identified. Finally, I consider worries related to convergence, bias, and ontology and defend the procedural, pragmatist account in light of those potential objections.

  6. Refining Hypertension Surveillance to Account for Potentially Misclassified Cases

    PubMed Central

    Peng, Mingkai; Chen, Guanmin; Lix, Lisa M.; McAlister, Finlay A.; Tu, Karen; Campbell, Norm R.; Hemmelgarn, Brenda R.; Svenson, Lawrence W.; Quan, Hude

    2015-01-01

    Administrative health data have been used in hypertension surveillance using the 1H2P method: the International Classification of Disease (ICD) hypertension diagnosis codes were recorded in at least 1 hospitalization or 2 physician claims within 2 year-period. Accumulation of false positive cases over time using the 1H2P method could result in the overestimation of hypertension prevalence. In this study, we developed and validated a new reclassification method to define hypertension cases using regularized logistic regression with the age, sex, hypertension and comorbidities in physician claims, and diagnosis of hypertension in hospital discharge data as independent variables. A Bayesian method was then used to adjust the prevalence estimated from the reclassification method. We evaluated the hypertension prevalence in data from Alberta, Canada using the currently accepted 1H2P method and these newly developed methods. The reclassification method with Bayesian adjustment produced similar prevalence estimates as the 1H2P method. This supports the continued use of the 1H2P method as a simple and practical way to conduct hypertension surveillance using administrative health data. PMID:25803682

  7. Accounting for population stratification in DNA methylation studies.

    PubMed

    Barfield, Richard T; Almli, Lynn M; Kilaru, Varun; Smith, Alicia K; Mercer, Kristina B; Duncan, Richard; Klengel, Torsten; Mehta, Divya; Binder, Elisabeth B; Epstein, Michael P; Ressler, Kerry J; Conneely, Karen N

    2014-04-01

    DNA methylation is an important epigenetic mechanism that has been linked to complex diseases and is of great interest to researchers as a potential link between genome, environment, and disease. As the scale of DNA methylation association studies approaches that of genome-wide association studies, issues such as population stratification will need to be addressed. It is well-documented that failure to adjust for population stratification can lead to false positives in genetic association studies, but population stratification is often unaccounted for in DNA methylation studies. Here, we propose several approaches to correct for population stratification using principal components (PCs) from different subsets of genome-wide methylation data. We first illustrate the potential for confounding due to population stratification by demonstrating widespread associations between DNA methylation and race in 388 individuals (365 African American and 23 Caucasian). We subsequently evaluate the performance of our PC-based approaches and other methods in adjusting for confounding due to population stratification. Our simulations show that (1) all of the methods considered are effective at removing inflation due to population stratification, and (2) maximum power can be obtained with single-nucleotide polymorphism (SNP)-based PCs, followed by methylation-based PCs, which outperform both surrogate variable analysis and genomic control. Among our different approaches to computing methylation-based PCs, we find that PCs based on CpG sites chosen for their potential to proxy nearby SNPs can provide a powerful and computationally efficient approach to adjust for population stratification in DNA methylation studies when genome-wide SNP data are unavailable.

  8. Accounting for population stratification in DNA methylation studies.

    PubMed

    Barfield, Richard T; Almli, Lynn M; Kilaru, Varun; Smith, Alicia K; Mercer, Kristina B; Duncan, Richard; Klengel, Torsten; Mehta, Divya; Binder, Elisabeth B; Epstein, Michael P; Ressler, Kerry J; Conneely, Karen N

    2014-04-01

    DNA methylation is an important epigenetic mechanism that has been linked to complex diseases and is of great interest to researchers as a potential link between genome, environment, and disease. As the scale of DNA methylation association studies approaches that of genome-wide association studies, issues such as population stratification will need to be addressed. It is well-documented that failure to adjust for population stratification can lead to false positives in genetic association studies, but population stratification is often unaccounted for in DNA methylation studies. Here, we propose several approaches to correct for population stratification using principal components (PCs) from different subsets of genome-wide methylation data. We first illustrate the potential for confounding due to population stratification by demonstrating widespread associations between DNA methylation and race in 388 individuals (365 African American and 23 Caucasian). We subsequently evaluate the performance of our PC-based approaches and other methods in adjusting for confounding due to population stratification. Our simulations show that (1) all of the methods considered are effective at removing inflation due to population stratification, and (2) maximum power can be obtained with single-nucleotide polymorphism (SNP)-based PCs, followed by methylation-based PCs, which outperform both surrogate variable analysis and genomic control. Among our different approaches to computing methylation-based PCs, we find that PCs based on CpG sites chosen for their potential to proxy nearby SNPs can provide a powerful and computationally efficient approach to adjust for population stratification in DNA methylation studies when genome-wide SNP data are unavailable. PMID:24478250

  9. Greenhouse gas accounting and waste management.

    PubMed

    Gentil, Emmanuel; Christensen, Thomas H; Aoustin, Emmanuelle

    2009-11-01

    Accounting of emissions of greenhouse gas (GHG) is a major focus within waste management. This paper analyses and compares the four main types of GHG accounting in waste management including their special features and approaches: the national accounting, with reference to the Intergovernmental Panel on Climate Change (IPCC), the corporate level, as part of the annual reporting on environmental issues and social responsibility, life-cycle assessment (LCA), as an environmental basis for assessing waste management systems and technologies, and finally, the carbon trading methodology, and more specifically, the clean development mechanism (CDM) methodology, introduced to support cost-effective reduction in GHG emissions. These types of GHG accounting, in principle, have a common starting point in technical data on GHG emissions from specific waste technologies and plants, but the limited availability of data and, moreover, the different scopes of the accounting lead to many ways of quantifying emissions and producing the accounts. The importance of transparency in GHG accounting is emphasised regarding waste type, waste composition, time period considered, GHGs included, global warming potential (GWP) assigned to the GHGs, counting of biogenic carbon dioxide, choice of system boundaries, interactions with the energy system, and generic emissions factors. In order to enhance transparency and consistency, a format called the upstream-operating-downstream framework (UOD) is proposed for reporting basic technology-related data regarding GHG issues including a clear distinction between direct emissions from waste management technologies, indirect upstream (use of energy and materials) and indirect downstream (production of energy, delivery of secondary materials) activities. PMID:19808731

  10. Interpreting the temperature of water at cold springs and the importance of gravitational potential energy

    NASA Astrophysics Data System (ADS)

    Manga, Michael; Kirchner, James W.

    2004-05-01

    Circulating groundwater transports heat. If groundwater flow velocities are sufficiently high, most of the subsurface heat transport can occur by advection. This is the case, for example, in the Cascades volcanic arc where much of the background geothermal heat is transported advectively and then discharged when the groundwater emerges at springs. The temperature of spring water can thus be used to infer the geothermal heat flux. If spring water temperature is many degrees warmer than the ambient temperature, as it is at hot springs, determining the heat discharged at springs is straightforward. At large-volume cold springs, however, the geothermal warming of water is small because the added heat is diluted in a large volume of water. We show that in order to interpret the temperature of cold springs we must account for three processes: (1) conversion of gravitational potential energy to heat through viscous dissipation, (2) conduction of heat to or from the Earth's surface, and (3) geothermal warming. Using spring temperature data from the central Oregon Cascades and Mount Shasta, California, we show that the warming due to surface heat exchange and dissipation of gravitational potential energy can be comparable to that due to geothermal heating. Unless these confounding sources of heating are taken into account, estimates of geothermal heat flux derived from temperatures of cold springs can be incorrect by large factors.

  11. Multimedia and Management Accounting: Adding Creativity to Accounting.

    ERIC Educational Resources Information Center

    Heisz, Mary A.; Blake, Catherine M.; Andrusyszyn, Mary-Anne

    2000-01-01

    Describes the development of an interactive multimedia accounting module for management accounting at the University of Western Ontario. Discusses results of a study of graduate students that investigated the influence of the module on learning and retention compared to traditional instruction as well as students' perceptions of the module.…

  12. The Voluntary System of Accountability for Accountability and Institutional Assessment

    ERIC Educational Resources Information Center

    Keller, Christine M.; Hammang, John M.

    2008-01-01

    The Voluntary System of Accountability (VSA) provides a framework for public universities to provide evidence of success and increase public confidence. The goals of the VSA are threefold: (1) Demonstrate greater accountability and stewardship to the public; (2) Enhance effective educational practices by measuring educational outcomes; and (3)…

  13. Accountability Reporting and Tracking System

    1992-07-02

    ARTS is a micro based prototype of the data elements, screens, and information processing rules that apply to the Accountability Reporting Program. The system focuses on the Accountability Event. The Accountability Event is an occurrence of incurring avoidable costs. The system must be able to CRUD (Create, Retrieve, Update, Delete) instances of the Accountability Event. Additionally, the system must provide for a review committee to update the ''event record'' with findings and determination information. Lastly,more » the system must provide for financial representatives to perform a cost reporting process.« less

  14. WAPA Daily Energy Accounting Activities

    1990-10-01

    ISA (Interchange, Scheduling, & Accounting) is the interchange scheduling system used by the DOE Western Area Power Administration to perform energy accounting functions associated with the daily activities of the Watertown Operations Office (WOO). The system's primary role is to provide accounting functions for scheduled energy which is exchanged with other power companies and power operating organizations. The system has a secondary role of providing a historical record of all scheduled interchange transactions. The followingmore » major functions are performed by ISA: scheduled energy accounting for received and delivered energy; generation scheduling accounting for both fossil and hydro-electric power plants; metered energy accounting for received and delivered totals; energy accounting for Direct Current (D.C.) Ties; regulation accounting; automatic generation control set calculations; accounting summaries for Basin, Heartland Consumers Power District, and the Missouri Basin Municipal Power Agency; calculation of estimated generation for the Laramie River Station plant; daily and monthly reports; and dual control areas.« less

  15. Accountability Reporting and Tracking System

    SciTech Connect

    Jones, Jeffery

    1992-07-02

    ARTS is a micro based prototype of the data elements, screens, and information processing rules that apply to the Accountability Reporting Program. The system focuses on the Accountability Event. The Accountability Event is an occurrence of incurring avoidable costs. The system must be able to CRUD (Create, Retrieve, Update, Delete) instances of the Accountability Event. Additionally, the system must provide for a review committee to update the ''event record'' with findings and determination information. Lastly, the system must provide for financial representatives to perform a cost reporting process.

  16. Acetic acid inhibits nutrient uptake in Saccharomyces cerevisiae: auxotrophy confounds the use of yeast deletion libraries for strain improvement.

    PubMed

    Ding, Jun; Bierma, Jan; Smith, Mark R; Poliner, Eric; Wolfe, Carole; Hadduck, Alex N; Zara, Severino; Jirikovic, Mallori; van Zee, Kari; Penner, Michael H; Patton-Vogt, Jana; Bakalinsky, Alan T

    2013-08-01

    Acetic acid inhibition of yeast fermentation has a negative impact in several industrial processes. As an initial step in the construction of a Saccharomyces cerevisiae strain with increased tolerance for acetic acid, mutations conferring resistance were identified by screening a library of deletion mutants in a multiply auxotrophic genetic background. Of the 23 identified mutations, 11 were then introduced into a prototrophic laboratory strain for further evaluation. Because none of the 11 mutations was found to increase resistance in the prototrophic strain, potential interference by the auxotrophic mutations themselves was investigated. Mutants carrying single auxotrophic mutations were constructed and found to be more sensitive to growth inhibition by acetic acid than an otherwise isogenic prototrophic strain. At a concentration of 80 mM acetic acid at pH 4.8, the initial uptake of uracil, leucine, lysine, histidine, tryptophan, phosphate, and glucose was lower in the prototrophic strain than in a non-acetic acid-treated control. These findings are consistent with two mechanisms by which nutrient uptake may be inhibited. Intracellular adenosine triphosphate (ATP) levels were severely decreased upon acetic acid treatment, which likely slowed ATP-dependent proton symport, the major form of transport in yeast for nutrients other than glucose. In addition, the expression of genes encoding some nutrient transporters was repressed by acetic acid, including HXT1 and HXT3 that encode glucose transporters that operate by facilitated diffusion. These results illustrate how commonly used genetic markers in yeast deletion libraries complicate the effort to isolate strains with increased acetic acid resistance.

  17. Variable selection for confounder control, flexible modeling and Collaborative Targeted Minimum Loss-based Estimation in causal inference

    PubMed Central

    Schnitzer, Mireille E.; Lok, Judith J.; Gruber, Susan

    2015-01-01

    This paper investigates the appropriateness of the integration of flexible propensity score modeling (nonparametric or machine learning approaches) in semiparametric models for the estimation of a causal quantity, such as the mean outcome under treatment. We begin with an overview of some of the issues involved in knowledge-based and statistical variable selection in causal inference and the potential pitfalls of automated selection based on the fit of the propensity score. Using a simple example, we directly show the consequences of adjusting for pure causes of the exposure when using inverse probability of treatment weighting (IPTW). Such variables are likely to be selected when using a naive approach to model selection for the propensity score. We describe how the method of Collaborative Targeted minimum loss-based estimation (C-TMLE; van der Laan and Gruber, 2010) capitalizes on the collaborative double robustness property of semiparametric efficient estimators to select covariates for the propensity score based on the error in the conditional outcome model. Finally, we compare several approaches to automated variable selection in low-and high-dimensional settings through a simulation study. From this simulation study, we conclude that using IPTW with flexible prediction for the propensity score can result in inferior estimation, while Targeted minimum loss-based estimation and C-TMLE may benefit from flexible prediction and remain robust to the presence of variables that are highly correlated with treatment. However, in our study, standard influence function-based methods for the variance underestimated the standard errors, resulting in poor coverage under certain data-generating scenarios. PMID:26226129

  18. Shared spatial effects on quantitative genetic parameters: accounting for spatial autocorrelation and home range overlap reduces estimates of heritability in wild red deer.

    PubMed

    Stopher, Katie V; Walling, Craig A; Morris, Alison; Guinness, Fiona E; Clutton-Brock, Tim H; Pemberton, Josephine M; Nussey, Daniel H

    2012-08-01

    Social structure, limited dispersal, and spatial heterogeneity in resources are ubiquitous in wild vertebrate populations. As a result, relatives share environments as well as genes, and environmental and genetic sources of similarity between individuals are potentially confounded. Quantitative genetic studies in the wild therefore typically account for easily captured shared environmental effects (e.g., parent, nest, or region). Fine-scale spatial effects are likely to be just as important in wild vertebrates, but have been largely ignored. We used data from wild red deer to build "animal models" to estimate additive genetic variance and heritability in four female traits (spring and rut home range size, offspring birth weight, and lifetime breeding success). We then, separately, incorporated spatial autocorrelation and a matrix of home range overlap into these models to estimate the effect of location or shared habitat on phenotypic variation. These terms explained a substantial amount of variation in all traits and their inclusion resulted in reductions in heritability estimates, up to an order of magnitude up for home range size. Our results highlight the potential of multiple covariance matrices to dissect environmental, social, and genetic contributions to phenotypic variation, and the importance of considering fine-scale spatial processes in quantitative genetic studies.

  19. Why revisit your cost-accounting strategy.

    PubMed

    Arredondo, Ricky

    2014-07-01

    Healthcare entities seeking to develop effective cost-accounting systems should take six steps to avoid potential pitfalls: Secure broad executive-level support for the effort. Ensure systems are in place to analyze the disparate data. Define measurable objectives to ensure that implementation achieves desired results. Give due consideration to implementation planning. Train support staff sufficiently to avoid underutilization. Develop a sufficiently broad base of staff support for the system.

  20. Revisiting heritability accounting for shared environmental effects and maternal inheritance.

    PubMed

    Liu, Chunyu; Dupuis, Josée; Larson, Martin G; Cupples, L Adrienne; Ordovas, Jose M; Vasan, Ramachandran S; Meigs, James B; Jacques, Paul F; Levy, Daniel

    2015-02-01

    Heritability measures the proportion of phenotypic variation attributable to genetic factors. In addition to a shared nuclear genetic component, a number of additional variance components, such as spousal correlation, sibship, household and maternal effects, may have strong contributions to inter-individual phenotype variation. In humans, the confounding effects of these components on heritability have not been studied thoroughly. We sought to obtain unbiased heritability estimates for complex traits in the presence of multiple variance components and also to estimate the contributions of these variance components to complex traits. We compared regression and variance component methods to estimate heritability in simulations when additional variance components existed. We then revisited heritability for several traits in Framingham Heart Study (FHS) participants. Using simulations, we found that failure to account for or misclassification of necessary variance components yielded biased heritability estimates. The direction and magnitude of the bias varied depending on a variance structure and an estimation method. Using the best fitted models to account for necessary variance components, we found that heritability estimates for most FHS traits were overestimated, ranging from 4 to 47 %, when we compared models that considered necessary variance components to models that only considered familial relationships. Spousal correlation explained 14-36 % of phenotypic variation in several anthropometric and lifestyle traits. Maternal and sibling effects also contributed to phenotypic variation, ranging from 3 to 5 % and 4 to 7 %, respectively, in several anthropometric and metabolic traits. Our findings may explain, in part, the missing heritability for some traits.

  1. Meaning: A Verbal Behavior Account

    ERIC Educational Resources Information Center

    Lowenkron, Barry

    2004-01-01

    Although the verbal operants that comprise Skinner's account of verbal behavior provide a seemingly complete description of the behavior of the speaker with respect to what is ordinarily called the expression of meanings, it may be shown that the account is intrinsically deficient in describing the receptive behavior of listeners with regard to…

  2. Efficacy and Accountability in Organizations.

    ERIC Educational Resources Information Center

    Reitzug, Ulrich C.

    This study examined the relationship among accountability, efficacy, and organizational effectiveness by integrating findings from 17 research and development reports on Management by Objectives (MBO), an intervention that incorporates elements and processes of both accountability (goal-setting, measuring and monitoring, feedback) and efficacy…

  3. Peer-to-peer accountability.

    PubMed

    Guidi, M A

    1995-10-01

    Peer-to-peer accountability is an essential component of empowerment-based management models. To foster this environment, skills such as conflict resolution, team building, communication and group dynamics need to be identified and supported. The lack of peer-to-peer accountability can seriously hinder the development of management models. PMID:7566813

  4. Revised Accounting for Business Combinations

    ERIC Educational Resources Information Center

    Wilson, Arlette C.; Key, Kimberly

    2008-01-01

    The Financial Accounting Standards Board (FASB) has recently issued Statement of Financial Accounting Standards No. 141 (Revised 2007) Business Combinations. The object of this Statement is to improve the relevance, representational faithfulness, and comparability of reported information about a business combination and its effects. This Statement…

  5. The Accountability Illusion: New Mexico

    ERIC Educational Resources Information Center

    Thomas B. Fordham Institute, 2009

    2009-01-01

    The intent of the No Child Left Behind (NCLB) Act of 2001 is to hold schools accountable for ensuring that all their students achieve mastery in reading and math, with a particular focus on groups that have traditionally been left behind. Under NCLB, states submit accountability plans to the U.S. Department of Education detailing the rules and…

  6. PLATO Instruction for Elementary Accounting.

    ERIC Educational Resources Information Center

    McKeown, James C.

    A progress report of a study using computer assisted instruction (CAI) materials for an elementary course in accounting principles is presented. The study was based on the following objectives: (1) improvement of instruction in the elementary accounting sequence, and (2) help for transfer students from two-year institutions. The materials under…

  7. GASB's Basis of Accounting Project.

    ERIC Educational Resources Information Center

    Kovlak, Daniel L.

    1986-01-01

    In July 1984, the Governmental Accounting Standards Board began its "Measurement Focus/Basis of Accounting" project, which addresses measurement issues and revenue and expenditure recognition problems involving governmental funds. This article explains the project's background, alternatives discussed by the board, and tentative conclusions and…

  8. The Accountability Illusion: Rhode Island

    ERIC Educational Resources Information Center

    Thomas B. Fordham Institute, 2009

    2009-01-01

    The intent of the No Child Left Behind (NCLB) Act of 2001 is to hold schools accountable for ensuring that all their students achieve mastery in reading and math, with a particular focus on groups that have traditionally been left behind. Under NCLB, states submit accountability plans to the U.S. Department of Education detailing the rules and…

  9. Canadian Accountants: Examining Workplace Learning

    ERIC Educational Resources Information Center

    Hicks, Elizabeth; Bagg, Robert; Doyle, Wendy; Young, Jeffrey D.

    2007-01-01

    Purpose: This paper seeks to examine workplace learning strategies, learning facilitators and learning barriers of public accountants in Canada across three professional levels--trainees, managers, and partners. Design/methodology/approach: Volunteer participants from public accounting firms in Nova Scotia and New Brunswick completed a demographic…

  10. Open Book Professional Accountancy Examinations

    ERIC Educational Resources Information Center

    Rowlands, J. E.; Forsyth, D.

    2006-01-01

    This article describes the structure and rationale for an open-book approach in professional accountancy examinations. The concept of knowledge management and the recognition that some knowledge ought to be embedded in the minds of professional accountants while other knowledge ought to be readily accessible and capable of application forms the…

  11. The Heavy Hand of Accountability

    ERIC Educational Resources Information Center

    Cory, Christopher T.

    1974-01-01

    This article describes one of the products of accountability in schools--floods of forms and paper work. It centers on the situation in California districts which have the most comprehensive accountability law, questioning whether the quest for this objective is a distraction from teaching. (JA)

  12. School Centered Evidence Based Accountability

    ERIC Educational Resources Information Center

    Milligan, Charles

    2015-01-01

    Achievement scores drive much of the effort in today's accountability system, however, there is much more that occurs in every school, every day. School Centered Evidence Based Accountability can be used from micro to macro giving School Boards and Administration a process for monitoring the results of the entire school operation effectively and…

  13. An Accounting International Experience Course

    ERIC Educational Resources Information Center

    Johnson, Leigh Redd; Rudolph, Holly R.; Seay, Robert A.

    2010-01-01

    Accounting students need practical opportunities to personally experience other cultures and international business practices if they are to effectively compete in today's global marketplace. In order to address this need, the Department of Accounting at Murray State University offers an international experience course which includes a short-term…

  14. Accounting Experiences in Collaborative Learning

    ERIC Educational Resources Information Center

    Edmond, Tracie; Tiggeman, Theresa

    2009-01-01

    This paper discusses incorporating collaborative learning into accounting classes as a response to the Accounting Education Change Commission's call to install a more active student learner in the classroom. Collaborative learning requires the students to interact with each other and with the material within the classroom setting. It is a…

  15. Accountability in Communication and Learning.

    ERIC Educational Resources Information Center

    Findley, Charles A.

    The purpose of this paper is to present a general overview of the nature of and the need for accountability in educational communication. To clarify the nature of a model that will facilitate accountability, a comparative analysis is constructed between a model for instructional design and a model for speech preparation. Detailed attention is…

  16. Incentives for Accountability. ERIC Digest.

    ERIC Educational Resources Information Center

    Lashway, Larry

    Policymakers and educators are taking a new look at incentives as they work to improve accountability systems. This ERIC Digest examines the role of rewards and sanctions in school reform and identifies key issues in implementing incentive systems. The new accountability is based on five components: carefully designed standards, assessments…

  17. A User-Oriented Focus to Evaluating Accountants' Writing Skills.

    ERIC Educational Resources Information Center

    Catanach, Anthony H., Jr.; Golen, Steven

    1996-01-01

    Reviews briefly accounting writing skill research, discusses the subject bias prevalent in that research, and relates this weakness to a potential bias toward grammar and syntax in curriculum development. Argues that the user of accounting information is an important but neglected party in the communication process, whose input should be…

  18. Implications of NCLB Accountability for Comprehensive School Reform

    ERIC Educational Resources Information Center

    Le Floch, Kerstin Carlson; Taylor, James E.; Thomsen, Kerri

    2006-01-01

    No Child Left Behind (NCLB) accountability mechanisms have the potential to derail comprehensive school reform (CSR) implementation. For those pursuing CSR, the question is how to reconcile the implementation of NCLB accountability mandates with ongoing CSR efforts. Drawing from longitudinal data from a national study of CSR, this article explores…

  19. 12 CFR 390.307 - Savings account.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 5 2013-01-01 2013-01-01 false Savings account. 390.307 Section 390.307 Banks... Savings Associations § 390.307 Savings account. The term savings account means any withdrawable account, except a demand account as defined in § 390.290, a tax and loan account, a note account, a United...

  20. 12 CFR 390.307 - Savings account.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 5 2012-01-01 2012-01-01 false Savings account. 390.307 Section 390.307 Banks... Savings Associations § 390.307 Savings account. The term savings account means any withdrawable account, except a demand account as defined in § 390.290, a tax and loan account, a note account, a United...

  1. 12 CFR 390.307 - Savings account.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 5 2014-01-01 2014-01-01 false Savings account. 390.307 Section 390.307 Banks... Savings Associations § 390.307 Savings account. The term savings account means any withdrawable account, except a demand account as defined in § 390.290, a tax and loan account, a note account, a United...

  2. 12 CFR 561.42 - Savings account.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 6 2014-01-01 2012-01-01 true Savings account. 561.42 Section 561.42 Banks and... SAVINGS ASSOCIATIONS § 561.42 Savings account. The term savings account means any withdrawable account, except a demand account as defined in § 561.16 of this chapter, a tax and loan account, a note account,...

  3. 12 CFR 561.42 - Savings account.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 6 2013-01-01 2012-01-01 true Savings account. 561.42 Section 561.42 Banks and... SAVINGS ASSOCIATIONS § 561.42 Savings account. The term savings account means any withdrawable account, except a demand account as defined in § 561.16 of this chapter, a tax and loan account, a note account,...

  4. 40 CFR 97.520 - Establishment of compliance accounts, assurance accounts, and general accounts.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... the 30-day period, the Administrator receives a correctly submitted TR NOX Ozone Season allowance... SO2 TRADING PROGRAMS TR NOX Ozone Season Trading Program § 97.520 Establishment of compliance accounts... representation under § 97.516, the Administrator will establish a compliance account for the TR NOX Ozone...

  5. 40 CFR 97.520 - Establishment of compliance accounts, assurance accounts, and general accounts.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... the 30-day period, the Administrator receives a correctly submitted TR NOX Ozone Season allowance... SO2 TRADING PROGRAMS TR NOX Ozone Season Trading Program § 97.520 Establishment of compliance accounts... representation under § 97.516, the Administrator will establish a compliance account for the TR NOX Ozone...

  6. Counting, accounting, and accountability: Helen Verran's relational empiricism.

    PubMed

    Kenney, Martha

    2015-10-01

    Helen Verran uses the term 'relational empiricism' to describe situated empirical inquiry that is attentive to the relations that constitute its objects of study, including the investigator's own practices. Relational empiricism draws on and reconfigures Science and Technology Studies' traditional concerns with reflexivity and relationality, casting empirical inquiry as an important and non-innocent world-making practice. Through a reading of Verran's postcolonial projects in Nigeria and Australia, this article develops a concept of empirical and political 'accountability' to complement her relational empiricism. In Science and an African Logic, Verran provides accounts of the relations that materialize her empirical objects. These accounts work to decompose her original objects, generating new objects that are more promising for the specific postcolonial contexts of her work. The process of decomposition is part of remaining accountable for her research methods and accountable to the worlds she is working in and writing about. This is a practice of narrating relations and learning to tell better technoscientific stories. What counts as better, however, is not given, but is always contextual and at stake. In this way, Verran acts not as participant-observer, but as participant-storyteller, telling stories to facilitate epistemic flourishing within and as part of a historically located community of practice. The understanding of accountability that emerges from this discussion is designed as a contribution, both practical and evocative, to the theoretical toolkit of Science and Technology Studies scholars who are interested in thinking concretely about how we can be more accountable to the worlds we study.

  7. Counting, accounting, and accountability: Helen Verran's relational empiricism.

    PubMed

    Kenney, Martha

    2015-10-01

    Helen Verran uses the term 'relational empiricism' to describe situated empirical inquiry that is attentive to the relations that constitute its objects of study, including the investigator's own practices. Relational empiricism draws on and reconfigures Science and Technology Studies' traditional concerns with reflexivity and relationality, casting empirical inquiry as an important and non-innocent world-making practice. Through a reading of Verran's postcolonial projects in Nigeria and Australia, this article develops a concept of empirical and political 'accountability' to complement her relational empiricism. In Science and an African Logic, Verran provides accounts of the relations that materialize her empirical objects. These accounts work to decompose her original objects, generating new objects that are more promising for the specific postcolonial contexts of her work. The process of decomposition is part of remaining accountable for her research methods and accountable to the worlds she is working in and writing about. This is a practice of narrating relations and learning to tell better technoscientific stories. What counts as better, however, is not given, but is always contextual and at stake. In this way, Verran acts not as participant-observer, but as participant-storyteller, telling stories to facilitate epistemic flourishing within and as part of a historically located community of practice. The understanding of accountability that emerges from this discussion is designed as a contribution, both practical and evocative, to the theoretical toolkit of Science and Technology Studies scholars who are interested in thinking concretely about how we can be more accountable to the worlds we study. PMID:26630820

  8. Accountancy--An Emerging Profession

    ERIC Educational Resources Information Center

    Ristino, Robert J.

    1971-01-01

    Today, the accountant is widely recognized as a well-educated, well rounded and respected member of his community....part of a professional fraternity that oversees the most complex of human designs--a nation's economy. (Editor)

  9. Accountability Starts with the Superintendent

    ERIC Educational Resources Information Center

    Ricketts, Kenneth E.

    1973-01-01

    Describes how Lawndale District, near Los Angeles, developed a system of accountability starting with the superintendent. Describes the subgoals and objectives developed by the superintendent in cooperation with the Board of Trustees and members of the community. (JF)

  10. The Accounting Curriculum in College

    ERIC Educational Resources Information Center

    Gustafson, George Axel

    1975-01-01

    In discussing the need for combination of theory and practice in the college accounting curriculum, the author presents a conceptual framework for the body of knowledge which teaches the student principles and puts them into practice through illustrations. (JT)

  11. Savings account for health care costs

    MedlinePlus

    ... Flexible Spending Accounts; Medical Savings Accounts; Health Reimbursement Arrangements; HSA; MSA; Archer MSA; FSA; HRA ... Account (HSA) Medical Savings Account (MSA) Flexible Spending Arrangement (FSA) Health Reimbursement Arrangement (HRA) Your employer may ...

  12. Trade-based carbon sequestration accounting.

    PubMed

    King, Dennis M

    2004-04-01

    This article describes and illustrates an accounting method to assess and compare "early" carbon sequestration investments and trades on the basis of the number of standardized CO2 emission offset credits they will provide. The "gold standard" for such credits is assumed to be a relatively riskless credit based on a CO2 emission reduction that provides offsets against CO2 emissions on a one-for-one basis. The number of credits associated with carbon sequestration needs to account for time, risk, durability, permanence, additionality, and other factors that future trade regulators will most certainly use to assign "official" credits to sequestration projects. The method that is presented here uses established principles of natural resource accounting and conventional rules of asset valuation to "score" projects. A review of 20 "early" voluntary United States based CO2 offset trades that involve carbon sequestration reveals that the assumptions that buyers, sellers, brokers, and traders are using to characterize the economic potential of their investments and trades vary enormously. The article develops a "universal carbon sequestration credit scoring equation" and uses two of these trades to illustrate the sensitivity of trade outcomes to various assumptions about how future trade auditors are likely to "score" carbon sequestration projects in terms of their "equivalency" with CO2 emission reductions. The article emphasizes the importance of using a standard credit scoring method that accounts for time and risk to assess and compare even unofficial prototype carbon sequestration trades. The scoring method illustrated in this article is a tool that can protect the integrity of carbon sequestration credit trading and can assist buyers and sellers in evaluating the real economic potential of prospective trades.

  13. Accounting and Accountability for Distributed and Grid Systems

    NASA Technical Reports Server (NTRS)

    Thigpen, William; McGinnis, Laura F.; Hacker, Thomas J.

    2001-01-01

    While the advent of distributed and grid computing systems will open new opportunities for scientific exploration, the reality of such implementations could prove to be a system administrator's nightmare. A lot of effort is being spent on identifying and resolving the obvious problems of security, scheduling, authentication and authorization. Lurking in the background, though, are the largely unaddressed issues of accountability and usage accounting: (1) mapping resource usage to resource users; (2) defining usage economies or methods for resource exchange; (3) describing implementation standards that minimize and compartmentalize the tasks required for a site to participate in a grid.

  14. 7 CFR 1770.12 - Supplementary accounts.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 12 2010-01-01 2010-01-01 false Supplementary accounts. 1770.12 Section 1770.12... Accounts § 1770.12 Supplementary accounts. (a) All borrowers shall maintain the supplementary accounts set forth in § 1770.15. These accounts conform in number and title with accounts prescribed in the...

  15. 12 CFR 561.42 - Savings account.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 5 2010-01-01 2010-01-01 false Savings account. 561.42 Section 561.42 Banks... AFFECTING ALL SAVINGS ASSOCIATIONS § 561.42 Savings account. The term savings account means any withdrawable account, except a demand account as defined in § 561.16 of this chapter, a tax and loan account, a...

  16. 7 CFR 1770.12 - Supplementary accounts.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 12 2013-01-01 2013-01-01 false Supplementary accounts. 1770.12 Section 1770.12... Accounts § 1770.12 Supplementary accounts. (a) All borrowers shall maintain the supplementary accounts set forth in § 1770.15. These accounts conform in number and title with accounts prescribed in the...

  17. 12 CFR 561.42 - Savings account.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 6 2012-01-01 2012-01-01 false Savings account. 561.42 Section 561.42 Banks... AFFECTING ALL SAVINGS ASSOCIATIONS § 561.42 Savings account. The term savings account means any withdrawable account, except a demand account as defined in § 561.16 of this chapter, a tax and loan account, a...

  18. 12 CFR 561.42 - Savings account.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 5 2011-01-01 2011-01-01 false Savings account. 561.42 Section 561.42 Banks... AFFECTING ALL SAVINGS ASSOCIATIONS § 561.42 Savings account. The term savings account means any withdrawable account, except a demand account as defined in § 561.16 of this chapter, a tax and loan account, a...

  19. 12 CFR 1030.4 - Account disclosures.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 8 2012-01-01 2012-01-01 false Account disclosures. 1030.4 Section 1030.4... Account disclosures. (a) Delivery of account disclosures—(1) Account opening. (i) General. A depository institution shall provide account disclosures to a consumer before an account is opened or a service...

  20. 7 CFR 1770.12 - Supplementary accounts.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 12 2011-01-01 2011-01-01 false Supplementary accounts. 1770.12 Section 1770.12... Accounts § 1770.12 Supplementary accounts. (a) All borrowers shall maintain the supplementary accounts set forth in § 1770.15. These accounts conform in number and title with accounts prescribed in the...

  1. 7 CFR 1770.12 - Supplementary accounts.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 12 2012-01-01 2012-01-01 false Supplementary accounts. 1770.12 Section 1770.12... Accounts § 1770.12 Supplementary accounts. (a) All borrowers shall maintain the supplementary accounts set forth in § 1770.15. These accounts conform in number and title with accounts prescribed in the...

  2. 7 CFR 1770.12 - Supplementary accounts.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 12 2014-01-01 2013-01-01 true Supplementary accounts. 1770.12 Section 1770.12... Accounts § 1770.12 Supplementary accounts. (a) All borrowers shall maintain the supplementary accounts set forth in § 1770.15. These accounts conform in number and title with accounts prescribed in the...

  3. 12 CFR 1030.4 - Account disclosures.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 9 2014-01-01 2014-01-01 false Account disclosures. 1030.4 Section 1030.4... Account disclosures. (a) Delivery of account disclosures—(1) Account opening. (i) General. A depository institution shall provide account disclosures to a consumer before an account is opened or a service...

  4. 12 CFR 1030.4 - Account disclosures.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 8 2013-01-01 2013-01-01 false Account disclosures. 1030.4 Section 1030.4... Account disclosures. (a) Delivery of account disclosures. (1) Account opening. (i) General. A depository institution shall provide account disclosures to a consumer before an account is opened or a service...

  5. 12 CFR 161.42 - Savings account.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 1 2013-01-01 2013-01-01 false Savings account. 161.42 Section 161.42 Banks... AFFECTING ALL SAVINGS ASSOCIATIONS § 161.42 Savings account. The term savings account means any withdrawable account, except a demand account as defined in § 161.16 of this chapter, a tax and loan account, a...

  6. 12 CFR 161.42 - Savings account.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 1 2012-01-01 2012-01-01 false Savings account. 161.42 Section 161.42 Banks... AFFECTING ALL SAVINGS ASSOCIATIONS § 161.42 Savings account. The term savings account means any withdrawable account, except a demand account as defined in § 161.16 of this chapter, a tax and loan account, a...

  7. 12 CFR 161.42 - Savings account.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 1 2014-01-01 2014-01-01 false Savings account. 161.42 Section 161.42 Banks... AFFECTING ALL SAVINGS ASSOCIATIONS § 161.42 Savings account. The term savings account means any withdrawable account, except a demand account as defined in § 161.16 of this chapter, a tax and loan account, a...

  8. MASS: An automated accountability system

    SciTech Connect

    Erkkila, B.H.; Kelso, F.

    1994-08-01

    All Department of Energy contractors who manage accountable quantities of nuclear materials are required to implement an accountability system that tracks, and records the activities associated with those materials. At Los Alamos, the automated accountability system allows data entry on computer terminals and data base updating as soon as the entry is made. It is also able to generate all required reports in a timely Fashion. Over the last several years, the hardware and software have been upgraded to provide the users with all the capability needed to manage a large variety of operations with a wide variety of nuclear materials. Enhancements to the system are implemented as the needs of the users are identified. The system has grown with the expanded needs of the user; and has survived several years of changing operations and activity. The user community served by this system includes processing, materials control and accountability, and nuclear material management personnel. In addition to serving the local users, the accountability system supports the national data base (NMMSS). This paper contains a discussion of several details of the system design and operation. After several years of successful operation, this system provides an operating example of how computer systems can be used to manage a very dynamic data management problem.

  9. Incorporating Calculators into the Accounting Curriculum. Accounting II.

    ERIC Educational Resources Information Center

    Clayton, John

    This document is a guide to aid teachers in incorporating the use of calculators in the high school Accounting II curriculum. The guide contains 16 learning modules. Each module consists of an introductory explanation, student performance objectives, content of the module, and teaching suggestions for using calculators in each application of…

  10. Accountability in Arab Bedouin Schools in Israel: Accountable to Whom?

    ERIC Educational Resources Information Center

    Mizel, Omar

    2009-01-01

    "School-based management" (SBM) rose to become a prominent trend in educational reform in Western countries during the last few decades of the 20th century and has likewise been introduced into a number of Asian and African nations. A key component of SBM is the increase of internal accountability within the school with the aim of improving…

  11. 76 FR 53378 - Cost Accounting Standards: Accounting for Insurance Costs

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-26

    ... published the SDP, ``Accounting for Insurance Costs'' (71 FR 4335) which in particular, addressed the use of... paragraph (6) of the preamble to CAS 416 (43 FR 42239, September 20, 1978), which stated: Obviously, a... circumstances.'' (See Preamble to CAS 416 (43 FR 42239, Sept. 20, 1978).) Although CAS 416 has been in...

  12. 18 CFR 367.1840 - Account 184, Clearing accounts.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... accounts. 367.1840 Section 367.1840 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY REGULATIONS UNDER THE PUBLIC UTILITY HOLDING COMPANY ACT OF 2005, FEDERAL... unless the items held relate to a future period....

  13. 18 CFR 367.1840 - Account 184, Clearing accounts.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... accounts. 367.1840 Section 367.1840 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY REGULATIONS UNDER THE PUBLIC UTILITY HOLDING COMPANY ACT OF 2005, FEDERAL... unless the items held relate to a future period....

  14. Management of a Septic Open Abdomen Patient with Spontaneous Jejunal Perforation after Emergent C/S with Confounding Factor of Mild Acute Pancreatitis

    PubMed Central

    Yetisir, Fahri; Sarer, Akgün Ebru; Acar, Hasan Zafer; Osmanoglu, Gokhan; Özer, Mehmet; Yaylak, Faik

    2016-01-01

    Introduction. We report the management of a septic Open Abdomen (OA) patient by the help of negative pressure therapy (NPT) and abdominal reapproximation anchor (ABRA) system in pregnant woman with spontaneous jejunal perforation after emergent cesarean section (C/S) with confounding factor of mild acute pancreatitis (AP). Presentation of Case. A 29-year-old and 34-week pregnant woman with AP underwent C/S. She was arrested after anesthesia induction and responded to cardiopulmonary resuscitation (CPR). There were only ash-colored serosanguinous fluid within abdomen during C/S. After C/S, she was transferred to intensive care unit (ICU) with vasopressor support. On postoperative 1st day, she underwent reoperation due to fecal fluid coming near the drainage. Leakage point could not be identified exactly and operation had to be deliberately abbreviated due to hemodynamic instability. NPT was applied. Two days later source control was provided by conversion of enteroatmospheric fistula (EAF) to jejunostomy. ABRA was added and OA was closed. No hernia developed at 10-month follow-up period. Conclusion. NPT application in septic OA patient may gain time to patient until adequate source control could be achieved. Using ABRA in conjunction with NPT increases the fascial closure rate in infected OA patient. PMID:27006853

  15. Management of a Septic Open Abdomen Patient with Spontaneous Jejunal Perforation after Emergent C/S with Confounding Factor of Mild Acute Pancreatitis.

    PubMed

    Yetisir, Fahri; Sarer, Akgün Ebru; Acar, Hasan Zafer; Osmanoglu, Gokhan; Özer, Mehmet; Yaylak, Faik

    2016-01-01

    Introduction. We report the management of a septic Open Abdomen (OA) patient by the help of negative pressure therapy (NPT) and abdominal reapproximation anchor (ABRA) system in pregnant woman with spontaneous jejunal perforation after emergent cesarean section (C/S) with confounding factor of mild acute pancreatitis (AP). Presentation of Case. A 29-year-old and 34-week pregnant woman with AP underwent C/S. She was arrested after anesthesia induction and responded to cardiopulmonary resuscitation (CPR). There were only ash-colored serosanguinous fluid within abdomen during C/S. After C/S, she was transferred to intensive care unit (ICU) with vasopressor support. On postoperative 1st day, she underwent reoperation due to fecal fluid coming near the drainage. Leakage point could not be identified exactly and operation had to be deliberately abbreviated due to hemodynamic instability. NPT was applied. Two days later source control was provided by conversion of enteroatmospheric fistula (EAF) to jejunostomy. ABRA was added and OA was closed. No hernia developed at 10-month follow-up period. Conclusion. NPT application in septic OA patient may gain time to patient until adequate source control could be achieved. Using ABRA in conjunction with NPT increases the fascial closure rate in infected OA patient. PMID:27006853

  16. Lung cancer mortality among nuclear workers of the Mayak facilities in the former Soviet Union. An updated analysis considering smoking as the main confounding factor.

    PubMed

    Kreisheimer, M; Sokolnikov, M E; Koshurnikova, N A; Khokhryakov, V F; Romanow, S A; Shilnikova, N S; Okatenko, P V; Nekolla, E A; Kellerer, A M

    2003-07-01

    A new analysis of lung cancer mortality in a cohort of male Mayak workers who started their employment in the plutonium and reprocessing plants between 1948 and 1958 has been carried out in terms of a relative risk model. The follow-up has been extended until 1999, moreover a new dosimetry system (DOSES2000) has been established. Particular emphasis has been given to a discrimination of the effects of external gamma-exposure and internal alpha-exposure due to incorporated plutonium. This study has also utilized and incorporated the information from a cohort of Mayak reactor workers, who were exposed only externally to gamma-rays. The influence of smoking as the main confounding factor for lung cancer has been studied. The baseline lung cancer mortality rate was not taken from national statistics but was derived from the cohort itself. The estimated excess relative risk for the plutonium alpha-rays was 0.23/Sv (95%CI: 0.16-0.31). The resulting risk coefficient for external gamma-ray exposure was very low with a statistically insignificant estimate of 0.058/Sv (95%CI: -0.072-0.20). The inferred relative risk for smokers was 16.5 (95%CI: 12.6-20.5).

  17. Accountability in the pesticide industry.

    PubMed

    Riggs, Peter; Waples, Megan

    2003-01-01

    To counter the lack of corporate accountability of the agrochemical industry for the damage caused by its perpetuation of the use of harmful chemical pesticides, the Rockefeller Brothers Fund staff in June 2002 brought together concerned scientists, lawyers, socially responsible investment professionals, and sustainable agriculture advocates at their Pocantico Conference Center. The group's objective was to communicate to market analysts the long-term downside risks of investments in pesticides, in the hope that dissemination of this information would contribute to increasing corporate accountability and safeguarding public and environmental health. Excerpts from its proceedings are presented. PMID:12749634

  18. Managerial accounting applications in radiology.

    PubMed

    Lexa, Frank James; Mehta, Tushar; Seidmann, Abraham

    2005-03-01

    We review the core issues in managerial accounting for radiologists. We introduce the topic and then explore its application to diagnostic imaging. We define key terms such as fixed cost, variable cost, marginal cost, and marginal revenue and discuss their role in understanding the operational and financial implications for a radiology facility by using a cost-volume-profit model. Our work places particular emphasis on the role of managerial accounting in understanding service costs, as well as how it assists executive decision making.

  19. Hospital cost accounting: implementing the system successfully.

    PubMed

    Burik, D; Duvall, T J

    1985-05-01

    To successfully implement a cost accounting system, certain key steps should be undertaken. These steps include developing and installing software; developing cost center budgets and inter-cost center allocations; developing service item standard costs; generating cost center level and patient level standard cost reports and reconciling these costs to actual costs; generating product line profitability reports and reconciling these reports to the financial statements; and providing ad hoc reporting capabilities. By following these steps, potential problems in the implementation process can be anticipated and avoided.

  20. 76 FR 8989 - Federal Acquisition Regulation; Updated Financial Accounting Standards Board Accounting References

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-16

    ... 9000-AM00 Federal Acquisition Regulation; Updated Financial Accounting Standards Board Accounting... to amend the Federal Acquisition Regulation (FAR) to update references to authoritative accounting standards owing to the Financial Accounting Standards Board's (FASB's) Accounting Standards...

  1. Aqueous Processing Material Accountability Instrumentation

    SciTech Connect

    Robert Bean

    2007-09-01

    Increased use of nuclear power will require new facilities. The U.S. has not built a new spent nuclear fuel reprocessing facility for decades. Reprocessing facilities must maintain accountability of their nuclear fuel. This survey report on the techniques used in current aqueous reprocessing facilities, and provides references to source materials to assist facility design efforts.

  2. VOE Accounting: Scope and Sequence.

    ERIC Educational Resources Information Center

    Nashville - Davidson County Metropolitan Public Schools, TN.

    This guide, which was written as an initial step in the development of a systemwide articulated curriculum sequence for all vocational programs within the Metropolitan Nashville Public School System, outlines the suggested scope and sequence of a 2-year program in accounting. The guide consists of a course description; general course objectives;…

  3. Avoiding "Profscam": For Accounting Educators.

    ERIC Educational Resources Information Center

    Dillaway, Manson P.

    In partial response to a recent best-seller decrying the so-called "ProfScam" scenario whereby professors downgrade undergraduate teaching in favor of often irrelevant research, the paper offers guidance to accounting faculty seeking to undertake meaningful publishable research. Recommendations are given for four stages in the research process:…

  4. Cost Accounting for Decision Makers.

    ERIC Educational Resources Information Center

    Kaneklides, Ann L.

    1985-01-01

    Underscores the importance of informed decision making through accurate anticipation of cost incurrence in light of changing economic and environmental conditions. Explains the concepts of cost accounting, full allocation of costs, the selection of an allocation base, the allocation of indirect costs, depreciation, and implications for community…

  5. New Federal Cost Accounting Regulations

    ERIC Educational Resources Information Center

    Wolff, George J.; Handzo, Joseph J.

    1973-01-01

    Discusses a new set of indirect cost accounting procedures which must be followed by school districts wishing to recover any indirect costs of administering federal grants and contracts. Also discusses the amount of indirect costs that may be recovered, computing indirect costs, classifying project costs, and restricted grants. (Author/DN)

  6. Accountability Issues in School Violence.

    ERIC Educational Resources Information Center

    Al-Bataineh, Adel T.

    This paper examines various reasons that would account for school violence and considers ways educators can help eliminate violence from schools. The negative impact of violence in the media and easy access to guns are mentioned as probable causes of violence in youth. Students who do not feel part of the school community often resort to violence…

  7. 46 CFR Sec. 5 - Accounting.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... AGENTS IN PREPARATION OF INVOICES AND PAYMENT OF COMPENSATION PURSUANT TO PROVISIONS OF NSA ORDER NO. 47 Sec. 5 Accounting. The General Agent shall record the amounts of compensation paid from the NSA... compensation paid under sections 3(a), 3(b), 3(c), and 3(d) of NSA Order No. 47. Note: Invoices and...

  8. 46 CFR Sec. 5 - Accounting.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... AGENTS IN PREPARATION OF INVOICES AND PAYMENT OF COMPENSATION PURSUANT TO PROVISIONS OF NSA ORDER NO. 47 Sec. 5 Accounting. The General Agent shall record the amounts of compensation paid from the NSA... compensation paid under sections 3(a), 3(b), 3(c), and 3(d) of NSA Order No. 47. Note: Invoices and...

  9. 46 CFR Sec. 5 - Accounting.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... AGENTS IN PREPARATION OF INVOICES AND PAYMENT OF COMPENSATION PURSUANT TO PROVISIONS OF NSA ORDER NO. 47 Sec. 5 Accounting. The General Agent shall record the amounts of compensation paid from the NSA... compensation paid under sections 3(a), 3(b), 3(c), and 3(d) of NSA Order No. 47. Note: Invoices and...

  10. 46 CFR Sec. 5 - Accounting.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... AGENTS IN PREPARATION OF INVOICES AND PAYMENT OF COMPENSATION PURSUANT TO PROVISIONS OF NSA ORDER NO. 47 Sec. 5 Accounting. The General Agent shall record the amounts of compensation paid from the NSA... compensation paid under sections 3(a), 3(b), 3(c), and 3(d) of NSA Order No. 47. Note: Invoices and...

  11. Needed: An Updated Accountability Model

    ERIC Educational Resources Information Center

    Tucker, Marc

    2015-01-01

    It must have seemed simple to the framers of No Child Left Behind. For years, they had poured more and more money into federal programs for schools, yet reading performance had not improved. It appeared that the money had gone down a rat hole, and Congress was ready to hold schools accountable. It was time to get tough. Unfortunately, the…

  12. Library Labor Cost Accounting System.

    ERIC Educational Resources Information Center

    Du Bois, Dan

    The Library Labor Cost Accounting System will provide visibility on current costs of manually processing library materials, at each campus as well as system-wide. The scope of the study includes the following: (1) 100 individual activities, grouped into 14 functional areas, e.g., Ordering, Receiving; and into 3 major operations: Acquisitions,…

  13. Accounting Principles and Financial Statements.

    ERIC Educational Resources Information Center

    Robinson, Daniel D.

    1973-01-01

    This document presents the background and analysis of the American Institute of Certified Public Accountants (AICPA) guide to auditing colleges and universities. Highlights include the approval of the market value option, the treatment of endowment gains, debt services as transfers, the decisions on pledges, the use of financial statements, the…

  14. Career Expectations of Accounting Students

    ERIC Educational Resources Information Center

    Elam, Dennis; Mendez, Francis

    2010-01-01

    The demographic make-up of accounting students is dramatically changing. This study sets out to measure how well the profession is ready to accommodate what may be very different needs and expectations of this new generation of students. Non-traditional students are becoming more and more of a tradition in the current college classroom.…

  15. Technology's Role in Accountability Reporting.

    ERIC Educational Resources Information Center

    Brooks-Young, Susan

    2003-01-01

    Discusses the stronger accountability required under the No Child Left Behind Act of 2001 and explores how Student Information Systems (SIS) or Student Management Systems may be used to meet the stringent reporting requirements of the new legislation. SIS can enable the school district to manipulate data to generate reports to suit various needs.…

  16. The Disparity of Principal Accountability

    ERIC Educational Resources Information Center

    Taylor, M. Kathryn

    2013-01-01

    This study begins with a review of court cases that have helped shape public education in America. Following the review is an analysis of federal reform in education from 1965 to the present, paired with educational leadership literature to highlight a disparity in what federal mandates and state policies have in place for accountability measures.…

  17. Fraud Education for Accounting Students.

    ERIC Educational Resources Information Center

    Peterson, Bonita K.

    2003-01-01

    Reports that limited fraud education takes place in accounting due to a crowded curriculum and misunderstanding of the extent of fraud. Suggests ways to develop content on the topic and provides a list of teaching materials (textbooks, workbooks, trade books, case materials, videos, and reference materials). (Contains 16 references.) (SK)

  18. Process Accountability in Curriculum Development.

    ERIC Educational Resources Information Center

    Gooler, Dennis D.; Grotelueschen, Arden

    This paper urges the curriculum developer to assume the accountability for his decisions necessitated by the actual ways our society functions. The curriculum developer is encouraged to recognize that he is a salesman with a commodity (the curriculum). He is urged to realize that if he cannot market the package to the customers (the various…

  19. Educational Accountability and Policy Feedback

    ERIC Educational Resources Information Center

    McDonnell, Lorraine M.

    2013-01-01

    Over the past 30 years, accountability policies have become more prominent in public K-12 education and have changed how teaching and learning are organized. It is less clear the extent to which these policies have altered the politics of education. This article begins to address that question through the lens of policy feedback. It identifies…

  20. 77 FR 40253 - Reserve Account

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-09

    ... this final rule Rural Development will now base the reserve account amount on a life-cycle analysis or... formula that will be used in the life cycle analysis. A commenter suggested defining the formula to be used in the life cycle analysis as this could serve as a chart. Having the chart could alleviate...