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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. PMID:26865945

  3. phMRI: methodological considerations for mitigating potential confounding factors

    PubMed Central

    Bourke, Julius H.; Wall, Matthew B.

    2015-01-01

    Pharmacological Magnetic Resonance Imaging (phMRI) is a variant of conventional MRI that adds pharmacological manipulations in order to study the effects of drugs, or uses pharmacological probes to investigate basic or applied (e.g., clinical) neuroscience questions. Issues that may confound the interpretation of results from various types of phMRI studies are briefly discussed, and a set of methodological strategies that can mitigate these problems are described. These include strategies that can be employed at every stage of investigation, from study design to interpretation of resulting data, and additional techniques suited for use with clinical populations are also featured. Pharmacological MRI is a challenging area of research that has both significant advantages and formidable difficulties, however with due consideration and use of these strategies many of the key obstacles can be overcome. PMID:25999812

  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 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

  6. 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

  7. 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

  8. Medications and surgical interventions for benign prostatic hyperplasia are potential confounders of prostate-specific antigen.

    PubMed

    Modi, Parth; Helfand, Brian T; McVary, Kevin T

    2010-07-01

    Prostate-specific antigen (PSA) is the most widely used marker for prostate cancer (CaP) screening and monitoring benign prostatic hyperplasia (BPH) progression. However, lack of an established abnormal threshold and the presence of other benign processes confound the interpretation of PSA levels. Many factors besides inflammation, trauma, and instrumentation can influence PSA levels; specifically, BPH and its associated medical and surgical therapies frequently complicate the interpretation of this serum blood test. For example, the commonly used 5 alpha reductase inhibitor (5ARI) medications directly affect PSA levels by decreasing prostate volume. The amount of time and potentially even the 5ARI formulary a patient is administered has been implicated to directly impact the degree of reduction in PSA (a proxy for prostate volume). In addition, each of the currently available surgical procedures for BPH appears to remove varying amounts of prostatic adenoma. This directly confounds CaP screening because each procedure is associated with a relatively specific postoperative nadir PSA level, and PSA kinetics are not well described in the literature. Taken together, it is important for clinicians to comprehend that BPH and its associated medical and surgical interventions should directly influence their interpretation of PSA and PSA velocity when screening for CaP or following BPH progression. PMID:20467844

  9. The assessment of cortisol in human hair: associations with sociodemographic variables and potential confounders.

    PubMed

    Dettenborn, L; Tietze, A; Kirschbaum, C; Stalder, T

    2012-11-01

    To inform the future use of hair cortisol measurement, we have investigated influences of potential confounding variables (natural hair colour, frequency of hair washes, age, sex, oral contraceptive (OC) use and smoking status) on hair cortisol levels. The main study sample comprised 360 participants (172 women) covering a wide range of ages (1-91 years; mean = 25.95). In addition, to more closely examine influences of natural hair colour and young age on hair cortisol levels, two additional samples comprising 69 participants with natural blond or dark brown hair (hair colour sample) as well as 28 young children and 34 adults (young age sample) were recruited. Results revealed a lack of an effect for natural hair colour, OC use, and smoking status on hair cortisol levels (all p's >0.10). No influence of frequency of hair washes was seen for proximal hair segments (p = 0.335) but for the third hair segment indicating lower cortisol content (p = 0.008). We found elevated hair cortisol levels in young children and older adults (p < 0.001). Finally, men showed higher hair cortisol levels than women (p = 0.002). The present data indicate that hair cortisol measurement provides a useful tool in stress-related psychobiological research when applied with the consideration of possible confounders including age and sex. PMID:22356099

  10. 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

  11. 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.

  12. 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

  13. 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. PMID:24749497

  14. 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

  15. KIR Genotypic Diversity Can Track Ancestries in Heterogeneous Populations: A Potential Confounder for Disease Association Studies

    PubMed Central

    Singh, Komal Manpreet; Phung, Yume T.; Kohla, Mohamed S.; Lan, Billy Y-A; Chan, Sharon; Suen, Diana L.; Murad, Sahar; Rheault, Shana; Davidson, Peter; Evans, Jennifer; Singh, Manpreet; Dohil, Sofie; Osorio, Robert W.; Wakil, Adil E.; Page, Kimberly; Feng, Sandy; Cooper, Stewart L.

    2014-01-01

    Killer cell immunoglobulin-like receptors (KIR) are encoded by highly polymorphic genes that regulate the activation of natural killer (NK) cells and other lymphocyte subsets, and likely play key roles in innate and adaptive immunity. Association studies increasingly implicate KIR in disease predisposition and outcome but could be confounded by unknown KIR genetic structure in heterogeneous populations. To examine this we characterized the diversity of 16 KIR genes in 712 Northern Californians (NC) stratified by selfassigned ethnicities, and compared the profiles of KIR polymorphism with other US and global populations using a reference database. Sixty-eight distinct KIR genotypes were characterized: 58 in 457 Caucasians (NCC); 17 in 47 African Americans (NCAA); 21 in 80 Asians (NCA); 20 in 74 Hispanics (NCH) and 18 in 54 “other” ethnicities (NCO). KIR genotype patterns and frequencies in the 4 defined ethnicities were compared with each other and with 34 global populations by phylogenetic analysis. Although there were no population-specific genotypes, the KIR genotype frequency patterns faithfully traced the ancestry of NCC, NCAA and NCA but not of NCH whose ancestries are known to be more heterogeneous. KIR genotype frequencies can therefore track ethnic ancestries in modern urban populations. Our data emphasize the importance of selecting ethnically matched controls in KIR based studies to avert spurious associations. PMID:21898189

  16. Diffusion Tensor Imaging in Young Children with Autism: Biological Effects and Potential Confounds

    PubMed Central

    Walker, Lindsay; Gozzi, Marta; Lenroot, Rhoshel; Thurm, Audrey; Behseta, Babak; Swedo, Susan; Pierpaoli, Carlo

    2012-01-01

    Background Diffusion tensor imaging (DTI) has been used over the past decade to study structural differences in the brains of children with autism compared to typically developing children. These studies generally find reduced fractional anisotropy (FA) and increased mean diffusivity (MD) in children with autism, however the regional pattern of findings varies greatly. Methods We used DTI to investigate the brains of sedated children with autism (N=39) and naturally asleep typically developing children (N=39) between 2 and 8 years of age. Tract Based Spatial Statistics (TBSS) and whole brain voxel-wise analysis were performed to investigate the regional distribution of differences between groups. Results In children with autism, we found significantly reduced FA in widespread regions, and increased MD only in posterior brain regions. Significant age by group interaction was found, indicating a difference in developmental trends of FA and MD between children with autism and typically developing children. The magnitude of the measured differences between groups was small, on the order of ~1–2%. Subjects and controls showed distinct regional differences in imaging artifacts that can affect DTI measures. Conclusions We found statistically significant differences in DTI metrics between children with autism and typically developing children, including different developmental trends of these metrics. However, this study indicates that between-group differences in DTI studies of autism should be interpreted with caution, as their small magnitude make these measurements particularly vulnerable to the effects of artifacts and confounds, which may lead to false positive and/or false negative biological inferences. PMID:22906515

  17. [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

  18. Metformin and Cancer Risk and Mortality: A Systematic Review and Meta-Analysis taking into account Biases and Confounders

    PubMed Central

    Gandini, Sara; Puntoni, Matteo; Heckman-Stoddard, Brandy M; Dunn, Barbara K; Ford, Leslie; DeCensi, Andrea; Szabo, Eva

    2014-01-01

    Previous meta-analyses have shown that the anti-diabetic agent metformin is associated with reduced cancer incidence and mortality. However, this effect has not been consistently demonstrated in animal models and recent epidemiological studies. We performed a meta-analysis with a focus on confounders and biases, including BMI, study type, and time related biases. We identified 71 articles published between January 1, 1966 to May 31, 2013 through Pubmed, ISI Web of Science (Science Citation Index Expanded), Embase, and the Cochrane library that were related to metformin and cancer incidence or mortality. Study characteristics and outcomes were abstracted for each study that met inclusion criteria. We included estimates from 47 independent studies and 65,540 cancer cases in diabetic patients. Overall cancer incidence was reduced by 31% (SRR=0.69, 95%CI: 0.52–0.90), although between-study heterogeneity was considerable (I2=88%). Cancer mortality was reduced by 34% (SRR=0.66, 95%CI: 0.54–0.81; I2=21%). BMI-adjusted studies and studies without time-related biases also showed significant reduction in cancer incidence (SRR=0.82, 95%CI: 0.70–0.96 with I2=76% and SRR=0.90; 95%CI: 0.89–0.91 with I2=56%, respectively), albeit with lesser magnitude (18% and 10% reduction, respectively). However, studies of cancer mortality and individual organ sites did not consistently show significant reductions across all types of analyses. Although these associations may not be causal, our results show that metformin may reduce cancer incidence and mortality in diabetic patients. However the reduction seems to be of modest magnitude and not affecting all populations equally. Clinical trials are needed to determine if these observations apply to non-diabetic populations and to specific organ sites. PMID:24985407

  19. Gene targeting: technical confounds and potential solutions in behavioral brain research.

    PubMed

    Gerlai, R

    2001-11-01

    Gene targeting allows one to create null mutations in mice and to analyze how the mutant organism responds to the lack of a single gene product. This has facilitated the molecular dissection of such complex characteristics as mammalian brain function and behavior, including learning, memory, aggression, and maternal behavior to mention a few. However, the interpretation of the phenotypical changes that arise in null mutant mice has been questioned. The possibility that genes other than the targeted one may contribute to phenotypical alterations has been raised and the importance of compensatory mechanisms has been brought to attention. This review focuses on recent advances in the literature that illustrate the caveats associated with gene targeting and also presents an overview of potential solutions for the discussed problems. PMID:11682088

  20. Divergent phenotypes in mutant TDP-43 transgenic mice highlight potential confounds in TDP-43 transgenic modeling.

    PubMed

    D'Alton, Simon; Altshuler, Marcelle; Cannon, Ashley; Dickson, Dennis W; Petrucelli, Leonard; Lewis, Jada

    2014-01-01

    The majority of cases of frontotemporal lobar degeneration and amyotrophic lateral sclerosis are pathologically defined by the cleavage, cytoplasmic redistribution and aggregation of TAR DNA binding protein of 43 kDa (TDP-43). To examine the contribution of these potentially toxic mechanisms in vivo, we generated transgenic mice expressing human TDP-43 containing the familial amyotrophic lateral sclerosis-linked M337V mutation and identified two lines that developed neurological phenotypes of differing severity and progression. The first developed a rapid cortical neurodegenerative phenotype in the early postnatal period, characterized by fragmentation of TDP-43 and loss of endogenous murine Tdp-43, but entirely lacking aggregates of ubiquitin or TDP-43. A second, low expressing line was aged to 25 months without a severe neurodegenerative phenotype, despite a 30% loss of mouse Tdp-43 and accumulation of lower molecular weight TDP-43 species. Furthermore, TDP-43 fragments generated during neurodegeneration were not C-terminal, but rather were derived from a central portion of human TDP-43. Thus we find that aggregation is not required for cell loss, loss of murine Tdp-43 is not necessarily sufficient in order to develop a severe neurodegenerative phenotype and lower molecular weight TDP-43 positive species in mouse models should not be inherently assumed to be representative of human disease. Our findings are significant for the interpretation of other transgenic studies of TDP-43 proteinopathy. PMID:24466128

  1. 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

  2. Potential confounding effects of benzyl alcohol as a formulation excipient support the elimination of the abnormal toxicity test from pharmacopoeias.

    PubMed

    Xie, Jianxun; Ottaviani, Giorgio; Sun, Kai; Lu, Mingqiu; Wu, Xiaoqin; Huang, Sunfeng; Bopst, Martin

    2015-11-01

    Benzyl alcohol is an excipient used in many drugs as a stabilizer. Depending on the amount present in drug formulations there might be confounding findings in the Abnormal Toxicity Test (ATT). The ATT is utilized as a quality control (QC) release test to detect extraneous contaminants according to national pharmacopoeias. Our study assessed the effects of benzyl alcohol as defined in ATT designs. This study - the first thorough evaluation of the confounding effects of benzyl alcohol on the ATT - was conducted in relation to particular health authority questions and was part of the root-cause analyses resulting from some transient behavioral findings observed in the test. Two strains of mice, CD-1 & Kunming, plus Hartley guinea pigs were administered intraperitoneally (ip), subcutaneously (sc), or intravenously (iv) with benzyl alcohol at dose level defined in the ATT design. In both mice and guinea pigs, only after ip administration, minimal behavioral changes were observed transiently within 2-3 min after administration. Therefore, the presence of benzyl alcohol in the product batch may confound the ATT results. This study provides further evidence to question the validity of the ATT for its intended use. PMID:26449397

  3. Accounting: Recordkeeping-Accounting Competencies Needed by Potential Office Workers

    ERIC Educational Resources Information Center

    Schmidt, B. June

    1978-01-01

    The recordkeeping-accounting competencies in business education curriculums should be those needed by all prospective office workers, not just bookkeepers. A task inventory booklet (developed by the Vocational Technical Education Consortium of States) completed by incumbent office workers showed that some of the recordkeeping-accounting tasks…

  4. Insulin-Like Growth Factor 1 (IGF-1) in Parkinson's Disease: Potential as Trait-, Progression- and Prediction Marker and Confounding Factors

    PubMed Central

    Binder, Gerhard; Weber, Karin; Apel, Anja; Roeben, Benjamin; Deuschle, Christian; Maechtel, Mirjam; Heger, Tanja; Nussbaum, Susanne; Gasser, Thomas; Maetzler, Walter; Berg, Daniela

    2016-01-01

    Introduction Biomarkers indicating trait, progression and prediction of pathology and symptoms in Parkinson's disease (PD) often lack specificity or reliability. Investigating biomarker variance between individuals and over time and the effect of confounding factors is essential for the evaluation of biomarkers in PD, such as insulin-like growth factor 1 (IGF-1). Materials and Methods IGF-1 serum levels were investigated in up to 8 biannual visits in 37 PD patients and 22 healthy controls (HC) in the longitudinal MODEP study. IGF-1 baseline levels and annual changes in IGF-1 were compared between PD patients and HC while accounting for baseline disease duration (19 early stage: ≤3.5 years; 18 moderate stage: >4 years), age, sex, body mass index (BMI) and common medical factors putatively modulating IGF-1. In addition, associations of baseline IGF-1 with annual changes of motor, cognitive and depressive symptoms and medication dose were investigated. Results PD patients in moderate (130±26 ng/mL; p = .004), but not early stages (115±19, p>.1), showed significantly increased baseline IGF-1 levels compared with HC (106±24 ng/mL; p = .017). Age had a significant negative correlation with IGF-1 levels in HC (r = -.47, p = .028) and no correlation in PD patients (r = -.06, p>.1). BMI was negatively correlated in the overall group (r = -.28, p = .034). The annual changes in IGF-1 did not differ significantly between groups and were not correlated with disease duration. Baseline IGF-1 levels were not associated with annual changes of clinical parameters. Discussion Elevated IGF-1 in serum might differentiate between patients in moderate PD stages and HC. However, the value of serum IGF-1 as a trait-, progression- and prediction marker in PD is limited as IGF-1 showed large inter- and intraindividual variability and may be modulated by several confounders. PMID:26967642

  5. 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

  6. 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

  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. Cord Blood Methylmercury and Fetal Growth Outcomes in Baltimore Newborns: Potential Confounding and Effect Modification by Omega-3 Fatty Acids, Selenium, and Sex

    PubMed Central

    Wells, Ellen M.; Herbstman, Julie B.; Lin, Yu Hong; Jarrett, Jeffery; Verdon, Carl P.; Ward, Cynthia; Caldwell, Kathleen L.; Hibbeln, Joseph R.; Witter, Frank R.; Halden, Rolf U.; Goldman, Lynn R.

    2015-01-01

    Background Methylmercury (MeHg) may affect fetal growth; however, prior research often lacked assessment of mercury speciation, confounders, and interactions. Objective Our objective was to assess the relationship between MeHg and fetal growth as well as the potential for confounding or interaction of this relationship from speciated mercury, fatty acids, selenium, and sex. Methods This cross-sectional study includes 271 singletons born in Baltimore, Maryland, 2004–2005. Umbilical cord blood was analyzed for speciated mercury, serum omega-3 highly unsaturated fatty acids (n-3 HUFAs), and selenium. Multivariable linear regression models controlled for gestational age, birth weight, maternal age, parity, prepregnancy body mass index, smoking, hypertension, diabetes, selenium, n-3 HUFAs, and inorganic mercury (IHg). Results Geometric mean cord blood MeHg was 0.94 μg/L (95% CI: 0.84, 1.07). In adjusted models for ponderal index, βln(MeHg) = –0.045 (g/cm3) × 100 (95% CI: –0.084, –0.005). There was no evidence of a MeHg × sex interaction with ponderal index. Contrastingly, there was evidence of a MeHg × n-3 HUFAs interaction with birth length [among low n-3 HUFAs, βln(MeHg) = 0.40 cm, 95% CI: –0.02, 0.81; among high n-3 HUFAs, βln(MeHg) = –0.15, 95% CI: –0.54, 0.25; p-interaction = 0.048] and head circumference [among low n-3 HUFAs, βln(MeHg) = 0.01 cm, 95% CI: –0.27, 0.29; among high n-3 HUFAs, βln(MeHg) = –0.37, 95% CI: –0.63, –0.10; p-interaction = 0.042]. The association of MeHg with birth weight and ponderal index was affected by n-3 HUFAs, selenium, and IHg. For birth weight, βln(MeHg) without these variables was –16.8 g (95% CI: –75.0, 41.3) versus –29.7 (95% CI: –93.9, 34.6) with all covariates. Corresponding values for ponderal index were –0.030 (g/cm3) × 100 (95% CI: –0.065, 0.005) and –0.045 (95% CI: –0.084, –0005). Conclusion We observed an association of increased MeHg with decreased ponderal index. There is

  9. 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

  10. Interpretational Confounding or Confounded Interpretations of Causal Indicators?

    PubMed Central

    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 intended by a researcher. This article questions the validity of evidence used to claim that causal indicators are inherently susceptible to interpretational confounding. Further, a simulation study demonstrates that causal indicator coefficients are stable across correctly-specified models. Determining the suitability of causal indicators has implications for the way we conceptualize measurement and build and evaluate measurement models. PMID:25530730

  11. 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…

  12. 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

  13. 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

  14. 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

  15. Confounded by sequencing depth in association studies of rare alleles.

    PubMed

    Garner, Chad

    2011-05-01

    Next-generation DNA sequencing technologies are facilitating large-scale association studies of rare genetic variants. The depth of the sequence read coverage is an important experimental variable in the next-generation technologies and it is a major determinant of the quality of genotype calls generated from sequence data. When case and control samples are sequenced separately or in different proportions across batches, they are unlikely to be matched on sequencing read depth and a differential misclassification of genotypes can result, causing confounding and an increased false-positive rate. Data from Pilot Study 3 of the 1000 Genomes project was used to demonstrate that a difference between the mean sequencing read depth of case and control samples can result in false-positive association for rare and uncommon variants, even when the mean coverage depth exceeds 30× in both groups. The degree of the confounding and inflation in the false-positive rate depended on the extent to which the mean depth was different in the case and control groups. A logistic regression model was used to test for association between case-control status and the cumulative number of alleles in a collapsed set of rare and uncommon variants. Including each individual's mean sequence read depth across the variant sites in the logistic regression model nearly eliminated the confounding effect and the inflated false-positive rate. Furthermore, accounting for the potential error by modeling the probability of the heterozygote genotype calls in the regression analysis had a relatively minor but beneficial effect on the statistical results. PMID:21328616

  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

    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…

  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. 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. PMID:26399256

  2. 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

  3. Are the apparent effects of cigarette smoking on lung and bladder cancers due to uncontrolled confounding by occupational exposures?

    PubMed

    Siemiatycki, J; Dewar, R; Krewski, D; Désy, M; Richardson, L; Franco, E

    1994-01-01

    It has been suggested that the well known associations between smoking and cancer may in part reflect inadequately controlled confounding due to occupational exposures. The purpose of the present analysis is to describe the association between cigarette smoking and both lung and bladder cancers, taking into account the potential confounding effects of over 300 covariates, most of which represent occupational exposures. A population-based case-control study was undertaken in Montreal to investigate the associations between a large variety of environmental and occupational exposures, on the one hand, and several types of cancer, on the other. Interviews were carried out with male incident cases of several sites of cancer, including 857 lung cancers and 484 bladder cancers. A group of non-smoking-related cancers, comprising 1,707 interviewed subjects, was used as one control group. Additionally, 533 population controls were interviewed and constituted a second control group. Interview information included detailed lifetime smoking histories, job histories, and other potential confounders. Each job history was reviewed by a team of experts who translated it into a history of occupational exposures. These occupational exposures, as well as nonoccupational covariates, were treated as potential confounders in the analysis of cigarette smoking effects. Regardless of whether population controls or cancer controls were used, the odds ratio (OR) between smoking and lung cancer (ranging from 12 to 16 for ever vs never smokers) was not materially affected by adjustment for occupational exposures. The odds ratios for bladder cancer (ranging from 2 to 3) were also unaffected by confounding due to occupational exposures.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8117783

  4. Determinants of congruency sequence effects without learning and memory confounds.

    PubMed

    Weissman, Daniel H; Jiang, Jiefeng; Egner, Tobias

    2014-10-01

    A common finding in distracter interference (e.g., Flanker) tasks is that the difference in mean reaction time (RT) between incongruent and congruent trials-the congruency effect-is smaller when the previous trial was incongruent relative to congruent. Over the past 2 decades, 2 main accounts of this congruency sequence effect (CSE) have been proposed. One posits that the CSE indexes trial-by-trial adjustments of cognitive control, which are triggered by expectation, response conflict, negative affect, or response suppression. The other holds that the CSE indexes feature integration and/or contingency learning processes that are confounded with congruency sequence in most studies. In 3 online experiments involving over 450 participants, we observed CSEs without such confounds when 2 preconditions were met: (a) stimulus-response translation could be completed more rapidly for the distracter than for the target and (b) the distracter and target appeared at the same location. We also found that CSE magnitude did not vary consistently with the size of the congruency effect. These findings reveal that CSEs can be observed in the absence of feature integration and contingency learning confounds, but impose important new constraints on certain cognitive control accounts of this phenomenon. PMID:25089574

  5. The fallacy of Ratio Correction to address confounding factors

    PubMed Central

    Karp, Natasha A; Segonds-Pichon, Anne; Gerdin, Anna-Karin B; Ramírez-Solis, Ramiro; White, Jacqueline K

    2014-01-01

    Scientists aspire to measure cause and effect. Unfortunately confounding variables, ones that are associated with both the probable cause and the outcome, can lead to an association that is true but potentially misleading. For example, altered body weight is often observed in a gene knockout, however many other variables, such as lean mass, will also change as the body weight changes. This leaves the researcher asking whether the change in that variable is expected for that change in weight. Ratio Correction, which is often referred to as Normalization, is a method used commonly to remove the effect of a confounding variable. Although Ratio Correction is used widely in biological research, it is not the method recommended in the statistical literature to address confounding factors; instead regression methods such as the analysis of covariance (ANCOVA) are proposed. This method examines the difference in means after adjusting for the confounding relationship. Using real data, this manuscript demonstrates how the Ratio Correction approach is flawed and can result in erroneous calls of significance leading to inappropriate biological conclusions. This arises as some of the underlying assumptions are not met. The manuscript goes on to demonstrate that researchers should use ANCOVA, and discusses how graphical tools can be used readily to judge the robustness of this method. This study is therefore a clear example of why assumption testing is an important component of a study and thus why it is included in the Animal Research: reporting of In Vivo Experiment (ARRIVE) guidelines. PMID:22829707

  6. Confounding in the Estimation of Mediation Effects.

    PubMed

    Li, Yan; Bienias, Julia L; Bennett, David A

    2007-03-01

    A mediation effect explains the relationship of a risk factor and an outcome through a mediator variable which is a step in their pathway. Under the assumption of no cycling in the causal relationship, we consider various situations in which a fourth variable may interfere the estimation of a mediation effect as a confounding factor. Our asymptotic results, which are supported by a Monte Carlo study, show that adjusting for confounding factors under certain conditions might lead to biased estimates. A general guideline is provided for when it is appropriate to adjust for confounding factors in estimating a mediation effect. We apply the guideline to the estimation of the mediation effect of Alzheimer's disease pathology in the relationship between the Apolipoprotein E ε4 allele and cognitive function among 125 deceased participants from the Religious Orders Study, a longitudinal, clinical-pathologic study of aging and Alzheimer's disease. PMID:17940582

  7. Confounding in the Estimation of Mediation Effects

    PubMed Central

    Li, Yan; Bienias, Julia L.; Bennett, David A.

    2007-01-01

    Summary A mediation effect explains the relationship of a risk factor and an outcome through a mediator variable which is a step in their pathway. Under the assumption of no cycling in the causal relationship, we consider various situations in which a fourth variable may interfere the estimation of a mediation effect as a confounding factor. Our asymptotic results, which are supported by a Monte Carlo study, show that adjusting for confounding factors under certain conditions might lead to biased estimates. A general guideline is provided for when it is appropriate to adjust for confounding factors in estimating a mediation effect. We apply the guideline to the estimation of the mediation effect of Alzheimer’s disease pathology in the relationship between the Apolipoprotein E ε4 allele and cognitive function among 125 deceased participants from the Religious Orders Study, a longitudinal, clinical-pathologic study of aging and Alzheimer’s disease. PMID:17940582

  8. 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 ...

  9. 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 ...

  10. [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

  11. 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

  12. Systematically missing confounders in individual participant data meta-analysis of observational cohort studies.

    PubMed

    Jackson, Dan; White, Ian; Kostis, J B; Wilson, A C; Folsom, A R; Wu, K; Chambless, L; Benderly, M; Goldbourt, U; Willeit, J; Kiechl, S; Yarnell, J W G; Sweetnam, P M; Elwood, P C; Cushman, M; Psaty, B M; Tracy, R P; Tybjaerg-Hansen, A; Haverkate, F; de Maat, M P M; Thompson, S G; Fowkes, F G R; Lee, A J; Smith, F B; Salomaa, V; Harald, K; Rasi, V; Vahtera, E; Jousilahti, P; D'Agostino, R; Kannel, W B; Wilson, P W F; Tofler, G; Levy, D; Marchioli, R; Valagussa, F; Rosengren, A; Wilhelmsen, L; Lappas, G; Eriksson, H; Cremer, P; Nagel, D; Curb, J D; Rodriguez, B; Yano, K; Salonen, J T; Nyyssönen, K; Tuomainen, T-P; Hedblad, B; Engström, G; Berglund, G; Loewel, H; Koenig, W; Hense, H W; Meade, T W; Cooper, J A; De Stavola, B; Knottenbelt, C; Miller, G J; Cooper, J A; Bauer, K A; Rosenberg, R D; Sato, S; Kitamura, A; Naito, Y; Iso, H; Salomaa, V; Harald, K; Rasi, V; Vahtera, E; Jousilahti, P; Palosuo, T; Ducimetiere, P; Amouyel, P; Arveiler, D; Evans, A E; Ferrieres, J; Juhan-Vague, I; Bingham, A; Schulte, H; Assmann, G; Cantin, B; Lamarche, B; Despres, J-P; Dagenais, G R; Tunstall-Pedoe, H; Lowe, G D O; Woodward, M; Ben-Shlomo, Y; Davey Smith, G; Palmieri, V; Yeh, J L; Meade, T W; Rudnicka, A; Brennan, P; Knottenbelt, C; Cooper, J A; Ridker, P; Rodeghiero, F; Tosetto, A; Shepherd, J; Lowe, G D O; Ford, I; Robertson, M; Brunner, E; Shipley, M; Feskens, E J M; Di Angelantonio, E; Kaptoge, S; Lewington, S; Lowe, G D O; Sarwar, N; Thompson, S G; Walker, M; Watson, S; White, I R; Wood, A M; Danesh, J

    2009-04-15

    One difficulty in performing meta-analyses of observational cohort studies is that the availability of confounders may vary between cohorts, so that some cohorts provide fully adjusted analyses while others only provide partially adjusted analyses. Commonly, analyses of the association between an exposure and disease either are restricted to cohorts with full confounder information, or use all cohorts but do not fully adjust for confounding. We propose using a bivariate random-effects meta-analysis model to use information from all available cohorts while still adjusting for all the potential confounders. Our method uses both the fully adjusted and the partially adjusted estimated effects in the cohorts with full confounder information, together with an estimate of their within-cohort correlation. The method is applied to estimate the association between fibrinogen level and coronary heart disease incidence using data from 154,012 participants in 31 cohorts PMID:19222087

  13. Does exposure prediction bias health effect estimation? The relationship between confounding adjustment and exposure prediction

    PubMed Central

    Dominici, Francesca

    2014-01-01

    In environmental epidemiology, we are often faced with two challenges. First, an exposure prediction model is needed to estimate the exposure to an agent of interest, ideally at the individual level. Second, when estimating the health-effect associated with the exposure, confounding adjustment is needed in the health-effects regression model. The current literature addresses these two challenges separately. That is, methods that account for measurement error in the predicted exposure often fail to acknowledge the possibility of confounding, while methods designed to control confounding often fail to acknowledge that the exposure has been predicted. In this paper, we consider exposure prediction and confounding adjustment in a health-effects regression model simultaneously. By using theoretical arguments and simulation studies, we show that the bias of a health-effect estimate is influenced by the exposure prediction model, the type of confounding adjustment used in the health-effects regression model, and the relationship between these two. Moreover, we argue that even with a health-effects regression model that properly adjusts for confounding, the use of a predicted exposure can bias the health-effect estimate unless all confounders included in the health-effects regression model are also included in the exposure prediction model. While these results of this paper were motivated by studies of environmental contaminants, they apply more broadly to any context where an exposure needs to be predicted. PMID:24815302

  14. 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

  15. Confounding effects of indirect connections on causality estimation.

    PubMed

    Vakorin, Vasily A; Krakovska, Olga A; McIntosh, Anthony R

    2009-10-30

    Addressing the issue of effective connectivity, this study focuses on effects of indirect connections on inferring stable causal relations: partial transfer entropy. We introduce a Granger causality measure based on a multivariate version of transfer entropy. The statistic takes into account the influence of the rest of the network (environment) on observed coupling between two given nodes. This formalism allows us to quantify, for a specific pathway, the total amount of indirect coupling mediated by the environment. We show that partial transfer entropy is a more sensitive technique to identify robust causal relations than its bivariate equivalent. In addition, we demonstrate the confounding effects of the variation in indirect coupling on the detectability of robust causal links. Finally, we consider the problem of model misspecification and its effect on the robustness of the observed connectivity patterns, showing that misspecifying the model may be an issue even for model-free information-theoretic approach. PMID:19628006

  16. Carotta: Revealing Hidden Confounder Markers in Metabolic Breath Profiles

    PubMed Central

    Hauschild, Anne-Christin; Frisch, Tobias; Baumbach, Jörg Ingo; Baumbach, Jan

    2015-01-01

    Computational breath analysis is a growing research area aiming at identifying volatile organic compounds (VOCs) in human breath to assist medical diagnostics of the next generation. While inexpensive and non-invasive bioanalytical technologies for metabolite detection in exhaled air and bacterial/fungal vapor exist and the first studies on the power of supervised machine learning methods for profiling of the resulting data were conducted, we lack methods to extract hidden data features emerging from confounding factors. Here, we present Carotta, a new cluster analysis framework dedicated to uncovering such hidden substructures by sophisticated unsupervised statistical learning methods. We study the power of transitivity clustering and hierarchical clustering to identify groups of VOCs with similar expression behavior over most patient breath samples and/or groups of patients with a similar VOC intensity pattern. This enables the discovery of dependencies between metabolites. On the one hand, this allows us to eliminate the effect of potential confounding factors hindering disease classification, such as smoking. On the other hand, we may also identify VOCs associated with disease subtypes or concomitant diseases. Carotta is an open source software with an intuitive graphical user interface promoting data handling, analysis and visualization. The back-end is designed to be modular, allowing for easy extensions with plugins in the future, such as new clustering methods and statistics. It does not require much prior knowledge or technical skills to operate. We demonstrate its power and applicability by means of one artificial dataset. We also apply Carotta exemplarily to a real-world example dataset on chronic obstructive pulmonary disease (COPD). While the artificial data are utilized as a proof of concept, we will demonstrate how Carotta finds candidate markers in our real dataset associated with confounders rather than the primary disease (COPD) and bronchial

  17. Carotta: Revealing Hidden Confounder Markers in Metabolic Breath Profiles.

    PubMed

    Hauschild, Anne-Christin; Frisch, Tobias; Baumbach, Jörg Ingo; Baumbach, Jan

    2015-01-01

    Computational breath analysis is a growing research area aiming at identifying volatile organic compounds (VOCs) in human breath to assist medical diagnostics of the next generation. While inexpensive and non-invasive bioanalytical technologies for metabolite detection in exhaled air and bacterial/fungal vapor exist and the first studies on the power of supervised machine learning methods for profiling of the resulting data were conducted, we lack methods to extract hidden data features emerging from confounding factors. Here, we present Carotta, a new cluster analysis framework dedicated to uncovering such hidden substructures by sophisticated unsupervised statistical learning methods. We study the power of transitivity clustering and hierarchical clustering to identify groups of VOCs with similar expression behavior over most patient breath samples and/or groups of patients with a similar VOC intensity pattern. This enables the discovery of dependencies between metabolites. On the one hand, this allows us to eliminate the effect of potential confounding factors hindering disease classification, such as smoking. On the other hand, we may also identify VOCs associated with disease subtypes or concomitant diseases. Carotta is an open source software with an intuitive graphical user interface promoting data handling, analysis and visualization. The back-end is designed to be modular, allowing for easy extensions with plugins in the future, such as new clustering methods and statistics. It does not require much prior knowledge or technical skills to operate. We demonstrate its power and applicability by means of one artificial dataset. We also apply Carotta exemplarily to a real-world example dataset on chronic obstructive pulmonary disease (COPD). While the artificial data are utilized as a proof of concept, we will demonstrate how Carotta finds candidate markers in our real dataset associated with confounders rather than the primary disease (COPD) and bronchial

  18. 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

  19. Processed Pseudogene Confounding Deletion/Duplication Assays for SMAD4.

    PubMed

    Millson, Alison; Lewis, Tracey; Pesaran, Tina; Salvador, David; Gillespie, Katrina; Gau, Chia-Ling; Pont-Kingdon, Genevieve; Lyon, Elaine; Bayrak-Toydemir, Pinar

    2015-09-01

    Mutations in SMAD4 have been associated with juvenile polyposis syndrome and combined juvenile polyposis/hereditary hemorrhagic telangiectasia syndrome. SMAD4 is part of the SMAD gene family. To date, there has been no report in the literature of a SMAD4 pseudogene. An unusual SMAD4 duplication pattern was seen in multiple patient samples using two different duplication/deletion platforms: multiplex ligation-dependent probe amplification and chromosomal microarray. Follow-up confirmatory testing included real-time quantitative PCR and sequencing of an exon/exon junction, all results leading to the conclusion of the existence of a processed pseudogene. Examination of clinical results from two laboratories found a frequency of 0.26% (12 in 4672 cases) for this processed pseudogene. This is the first report of the presence of a processed pseudogene for SMAD4. We believe that knowledge of its existence is important for accurate interpretation of clinical diagnostic test results and for new assay designs. This study also indicates how a processed pseudogene may confound quantitative results, dependent on placement of probes and/or primers in a particular assay design, potentially leading to both false-positive and false-negative results. We also found that the SMAD4 processed pseudogene affects next-generation sequencing results by confounding the alignment of the sequences, resulting in erroneous variant calls. We recommend Sanger sequencing confirmation for SMAD4 variants. PMID:26165824

  20. 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

  1. Does Electroencephalogram Phase Variability Account for Reduced P3 Brain Potential in Externalizing Disorders?

    PubMed Central

    Burwell, Scott J.; Malone, Stephen M.; Bernat, Edward M.; Iacono, William G.

    2014-01-01

    Objective Amplitude deficits of the P3 event-related potential (ERP) are associated with externalizing psychopathology but little is known about the nature of underlying brain electrical activity that accounts for this amplitude reduction. We sought to understand if group differences in task-induced phase-locking in electroencephalographic (EEG) delta and theta frequencies may account for P3-externalizing associations. Methods Adult males (N = 410) completed a visual oddball task and frontal and parietal P3-related delta- and theta-band phase-invariant evoked energy and inter-trial phase-locking measures were investigated with respect to the externalizing spectrum, including substance dependence, adult antisociality, and childhood disruptive disorders. We hypothesized that P3-related phase-locking is weaker in externalizing-diagnosed individuals and this might mediate prior findings of reduced evoked P3energy. Results Reductions in both evoked energy and phase-locking, in both frequency bands, at both scalp sites, were associated with greater odds of externalizing diagnoses. Generally, adding phase-locking to evoked energy came with better prediction model fit. Moreover, reduced theta-band phase-locking partially mediated the effects of within-frequency evoked energy on externalizing prediction. Conclusions Inter-trial phase-locking underlying P3 appears to be an important distinction between externalizing and control subjects. Significance This cross-trial phase-variability for externalizing-diagnosed individuals might reflect deficient top-down “tuning” by neuromodulatory systems. PMID:24656843

  2. Confounding Factors in the Transcriptome Analysis of an In-Vivo Exposure Experiment

    PubMed Central

    Wackers, Paul F. K.; van Oostrom, Conny; Jonker, Martijs J.; Dekker, Rob J.; Rauwerda, Han; Ensink, Wim A.; de Vries, Annemieke; Breit, Timo M.

    2016-01-01

    Confounding factors In transcriptomics experimentation, confounding factors frequently exist alongside the intended experimental factors and can severely influence the outcome of a transcriptome analysis. Confounding factors are regularly discussed in methodological literature, but their actual, practical impact on the outcome and interpretation of transcriptomics experiments is, to our knowledge, not documented. For instance, in-vivo experimental factors; like Individual, Sample-Composition and Time-of-Day are potentially formidable confounding factors. To study these confounding factors, we designed an extensive in-vivo transcriptome experiment (n = 264) with UVR exposure of murine skin containing six consecutive samples from each individual mouse (n = 64). Analysis Approach Evaluation of the confounding factors: Sample-Composition, Time-of-Day, Handling-Stress, and Individual-Mouse resulted in the identification of many genes that were affected by them. These genes sometimes showed over 30-fold expression differences. The most prominent confounding factor was Sample-Composition caused by mouse-dependent skin composition differences, sampling variation and/or influx/efflux of mobile cells. Although we can only evaluate these effects for known cell type specifically expressed genes in our complex heterogeneous samples, it is clear that the observed variations also affect the cumulative expression levels of many other non-cell-type-specific genes. ANOVA ANOVA analysis can only attempt to neutralize the effects of the well-defined confounding factors, such as Individual-Mouse, on the experimental factors UV-Dose and Recovery-Time. Also, by definition, ANOVA only yields reproducible gene-expression differences, but we found that these differences were very small compared to the fold changes induced by the confounding factors, questioning the biological relevance of these ANOVA-detected differences. Furthermore, it turned out that many of the differentially expressed

  3. 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

  4. 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

  5. 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

  6. 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.

  7. 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

  8. Methods to control for unmeasured confounding in pharmacoepidemiology: an overview.

    PubMed

    Uddin, Md Jamal; Groenwold, Rolf H H; Ali, Mohammed Sanni; de Boer, Anthonius; Roes, Kit C B; Chowdhury, Muhammad A B; Klungel, Olaf H

    2016-06-01

    Background Unmeasured confounding is one of the principal problems in pharmacoepidemiologic studies. Several methods have been proposed to detect or control for unmeasured confounding either at the study design phase or the data analysis phase. Aim of the Review To provide an overview of commonly used methods to detect or control for unmeasured confounding and to provide recommendations for proper application in pharmacoepidemiology. Methods/Results Methods to control for unmeasured confounding in the design phase of a study are case only designs (e.g., case-crossover, case-time control, self-controlled case series) and the prior event rate ratio adjustment method. Methods that can be applied in the data analysis phase include, negative control method, perturbation variable method, instrumental variable methods, sensitivity analysis, and ecological analysis. A separate group of methods are those in which additional information on confounders is collected from a substudy. The latter group includes external adjustment, propensity score calibration, two-stage sampling, and multiple imputation. Conclusion As the performance and application of the methods to handle unmeasured confounding may differ across studies and across databases, we stress the importance of using both statistical evidence and substantial clinical knowledge for interpretation of the study results. PMID:27091131

  9. The Table 2 Fallacy: Presenting and Interpreting Confounder and Modifier Coefficients

    PubMed Central

    Westreich, Daniel; Greenland, Sander

    2013-01-01

    It is common to present multiple adjusted effect estimates from a single model in a single table. For example, a table might show odds ratios for one or more exposures and also for several confounders from a single logistic regression. This can lead to mistaken interpretations of these estimates. We use causal diagrams to display the sources of the problems. Presentation of exposure and confounder effect estimates from a single model may lead to several interpretative difficulties, inviting confusion of direct-effect estimates with total-effect estimates for covariates in the model. These effect estimates may also be confounded even though the effect estimate for the main exposure is not confounded. Interpretation of these effect estimates is further complicated by heterogeneity (variation, modification) of the exposure effect measure across covariate levels. We offer suggestions to limit potential misunderstandings when multiple effect estimates are presented, including precise distinction between total and direct effect measures from a single model, and use of multiple models tailored to yield total-effect estimates for covariates. PMID:23371353

  10. 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. PMID:26198689

  11. 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

  12. 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,…

  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.

    2012-08-01

    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.

  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.

    2012-04-01

    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.

  15. Reducing Bias Amplification in the Presence of Unmeasured Confounding Through Out-of-Sample Estimation Strategies for the Disease Risk Score

    PubMed Central

    Wyss, Richard; Lunt, Mark; Brookhart, M. Alan; Glynn, Robert J.; Stürmer, Til

    2014-01-01

    The prognostic score, or disease risk score (DRS), is a summary score that is used to control for confounding in non-experimental studies. While the DRS has been shown to effectively control for measured confounders, unmeasured confounding continues to be a fundamental obstacle in non-experimental research. Both theory and simulations have shown that in the presence of unmeasured confounding, controlling for variables that affect treatment (both instrumental variables and measured confounders) amplifies the bias caused by unmeasured confounders. In this paper, we use causal diagrams and path analysis to review and illustrate the process of bias amplification. We show that traditional estimation strategies for the DRS do not avoid bias amplification when controlling for predictors of treatment. We then discuss estimation strategies for the DRS that can potentially reduce bias amplification that is caused by controlling both instrumental variables and measured confounders. We show that under certain assumptions, estimating the DRS in populations outside the defined study cohort where treatment has not been introduced, or in outside populations with reduced treatment prevalence can control for the confounding effects of measured confounders while at the same time reduce bias amplification. PMID:25313347

  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. 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…

  18. Doubly robust methods for handling confounding by cluster.

    PubMed

    Zetterqvist, Johan; Vansteelandt, Stijn; Pawitan, Yudi; Sjölander, Arvid

    2016-04-01

    In clustered designs such as family studies, the exposure-outcome association is usually confounded by both cluster-constant and cluster-varying confounders. The influence of cluster-constant confounders can be eliminated by studying the exposure-outcome association within (conditional on) clusters, but additional regression modeling is usually required to control for observed cluster-varying confounders. A problem is that the working regression model may be misspecified, in which case the estimated within-cluster association may be biased. To reduce sensitivity to model misspecification we propose to augment the standard working model for the outcome with an auxiliary working model for the exposure. We derive a doubly robust conditional generalized estimating equation (DRCGEE) estimator for the within-cluster association. This estimator combines the two models in such a way that it is consistent if either model is correct, not necessarily both. Thus, the DRCGEE estimator gives the researcher two chances instead of only one to make valid inference on the within-cluster association. We have implemented the estimator in an R package and we use it to examine the association between smoking during pregnancy and cognitive abilities in offspring, in a sample of siblings. PMID:26508769

  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. PMID:27046778

  20. 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

  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. 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. PMID:25756869

  3. 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

  4. 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

  5. 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. PMID:27285260

  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. 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.

  8. 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

  9. Smoking during pregnancy and offspring externalizing problems: An exploration of genetic and environmental confounds

    PubMed Central

    D’Onofrio, Brian M.; Van Hulle, Carol A.; Waldman, Irwin D.; Rodgers, Joseph Lee; Harden, K. Paige; Rathouz, Paul J.; Lahey, Benjamin B.

    2013-01-01

    Previous studies have documented that smoking during pregnancy (SDP) is associated with offspring externalizing problems, even when measured covariates were used to control for possible confounds. However, the association may be due to non-measured environmental and genetic factors that increase risk for offspring externalizing problems. The current project used the National Longitudinal Survey of Youth and their children, ages 4–10 years, to explore the relations between SDP and offspring conduct problems (CP), oppositional-defiant problems (ODP), and attention deficit hyperactivity problems (ADHP) using methodological and statistical controls for confounds. When offspring were compared to their own siblings who differed in their exposure to prenatal nicotine, there was no effect of SDP on offspring CP and ODP. This suggests that SDP does not have a causal effect on offspring CP and ODP. There was a small association between SDP and ADHP, consistent with a causal effect of SDP, but the magnitude of the association was greatly reduced by methodological and statistical controls. Genetically informed analyses suggest that unmeasured environmental variables influencing both SDP and offspring externalizing behaviors account for the previously observed associations. That is, the current analyses imply that important unidentified environmental factors account for the association between SDP and offspring externalizing problems, not teratogenic effects of SDP. PMID:18211732

  10. Accounting for Accountability.

    ERIC Educational Resources Information Center

    Colorado State Dept. of Education, Denver. Cooperative Accountability Project.

    This publication reports on two Regional Educational Accountability Conferences on Techniques sponsored by the Cooperative Accountability Project. Accountability is described as an "emotionally-charged issue" and an "operationally demanding concept." Overviewing accountability, major speakers emphasized that accountability is a means toward…

  11. Clinical and Evoked Pain, Personality Traits, and Emotional States: Can Familial Confounding Explain the Associations?

    PubMed Central

    Dansie, Elizabeth; Succop, Annemarie; Chopko, Laura; Afari, Niloofar

    2014-01-01

    Objectives Pain is a complex phenomenon influenced by context and person-specific factors. Affective dimensions of pain involve both enduring personality traits and fleeting emotional states. We examined how personality traits and emotional states are linked with clinical and evoked pain in a twin sample. Methods 99 female twin pairs were evaluated for clinical and evoked pain using the McGill Pain Questionnaire (MPQ) and dolorimetry, and completed the 120-item International Personality Item Pool (IPIP), the Positive and Negative Affect Scale (PANAS), and ratings of stress and mood. Using a co-twin control design we examined a) the relationship of personality traits and emotional states with clinical and evoked pain, and b) whether genetics and common environment (i.e. familial factors) may account for the associations. Results Neuroticism was associated with the sensory component of the MPQ; this relationship was not confounded by familial factors. None of the emotional state measures was associated with the MPQ. PANAS Negative Affect was associated with lower evoked pressure pain threshold and tolerance; these associations were confounded by familial factors. There were no associations between IPIP traits and evoked pain. Conclusions A relationship exists between neuroticism and clinical pain that is not confounded by familial factors. There is no similar relationship between negative emotional states and clinical pain. In contrast, the relationship between negative emotional states and evoked pain is strong while the relationship with enduring personality traits is weak. The relationship between negative emotional states and evoked pain appears to be non-causal and due to familial factors. PMID:25311873

  12. 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. PMID:26769723

  13. 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. PMID:23192456

  14. 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

  15. 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

  16. 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

  17. 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

  18. Antimony: an unlikely confounder in the relationship between well water arsenic and health outcomes in Bangladesh.

    PubMed Central

    McCarty, Kathleen M; Senn, David B; Kile, Molly L; Quamruzzaman, Quazi; Rahman, Mahmuder; Mahiuddin, Golam; Christiani, David C

    2004-01-01

    Recent in vitro studies have suggested a potential role for antimony as a confounder in human health studies related to arsenic in drinking water. We measured tube-well water concentrations of antimony and arsenic in the Pabna region of Bangladesh, where arsenic concentrations are known to be elevated and the concentrations of antimony have not yet been thoroughly documented. Two hundred forty-five tube-well water samples were collected from various regions in Pabna, Bangladesh, as part of an ongoing case-control study. Water samples were analyzed for arsenic and antimony concentrations by inductively coupled plasma-mass spectrometry using U.S. Environmental Protection Agency method 200.8. The arsenic concentrations in the tube-well water samples ranged from < 1 microg/L to 747 microg/L. All 245 water samples had antimony concentrations < 1 microg/L. Based on consideration of the concentrations used the in vitro studies compared with field-observed concentrations, our results do not support the hypothesis that antimony would be a significant confounder in observed relationships between arsenic exposure through drinking water and potential health outcomes in Pabna, Bangladesh. PMID:15175164

  19. 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

  20. Adjusting for confounding by neighborhood using complex survey data.

    PubMed

    Brumback, Babette A; He, Zhulin

    2011-04-30

    Recently, we examined methods of adjusting for confounding by neighborhood of an individual exposure effect on a binary outcome, using complex survey data; the methods were found to fail when the neighborhood sample sizes are small and the selection bias is strongly informative. More recently, other authors have adapted an older method from the genetics literature for application to complex survey data; their adaptation achieves a consistent estimator under a broad range of circumstances. The method is based on weighted pseudolikelihoods, in which the contribution from each neighborhood involves all pairs of cases and controls in the neighborhood. The pairs are treated as if they were independent, a pairwise pseudo-conditional likelihood is thus derived, and then the corresponding score equation is weighted with inverse-probabilities of sampling each case-control pair. We have greatly simplified the implementation by translating the pairwise pseudo-conditional likelihood into an equivalent ordinary weighted log-likelihood formulation. We show how to program the method using standard software for ordinary logistic regression with complex survey data (e.g. SAS PROC SURVEYLOGISTIC). We also show that the methodology applies to a broader set of sampling scenarios than the ones considered by the previous authors. We demonstrate the validity of our simplified implementation by applying it to a simulation for which previous methods failed; the new method performs beautifully. We also apply the new method to an analysis of 2009 National Health Interview Survey (NHIS) public-use data, to estimate the effect of education on health insurance coverage, adjusting for confounding by neighborhood. PMID:21287588

  1. LD Score regression distinguishes confounding from polygenicity in genome-wide association studies.

    PubMed

    Bulik-Sullivan, Brendan K; Loh, Po-Ru; Finucane, Hilary K; Ripke, Stephan; Yang, Jian; Patterson, Nick; Daly, Mark J; Price, Alkes L; Neale, Benjamin M

    2015-03-01

    Both polygenicity (many small genetic effects) and confounding biases, such as cryptic relatedness and population stratification, can yield an inflated distribution of test statistics in genome-wide association studies (GWAS). However, current methods cannot distinguish between inflation from a true polygenic signal and bias. We have developed an approach, LD Score regression, that quantifies the contribution of each by examining the relationship between test statistics and linkage disequilibrium (LD). The LD Score regression intercept can be used to estimate a more powerful and accurate correction factor than genomic control. We find strong evidence that polygenicity accounts for the majority of the inflation in test statistics in many GWAS of large sample size. PMID:25642630

  2. 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. PMID:25776013

  3. Hamilton study: distribution of factors confounding the relationship between air quality and respiratory health

    SciTech Connect

    Pengelly, L.D.; Kerigan, A.T.; Goldsmith, C.H.; Inman, E.M.

    1984-10-01

    Hamilton, Ontario is an industrial city with a population of 300,000 which is situated at the western end of Lake Ontario. Canada's two largest iron and steel mills are located here; the city historically has had relatively poor air quality, which has improved markedly in the last 25 years. Concern about the health effects of current air quality recently led us to carry out an epidemiological study of the effects of air pollution on the respiratory health of over 3500 school children. Respiratory health was measured by pulmonary function testing of each child, and by an assessment of each child's respiratory symptoms via a questionnaire administered to the parents. Previous studies had shown that other environmental factors (e.g. parental smoking, parental cough, socioeconomic level, housing, and gas cooking) might also affect respiratory health, and thus confound any potential relationships between health and air pollution. The questionnaire also collected information on many of these confounding factors. For the purposes of initial analysis, the city was divided into five areas in which differences in air quality were expected. In general, factors which have been associated with poor respiratory health were observed to be more prevalent in areas of poorer air quality.

  4. 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.

  5. 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

  6. Counterfactual graphical models for longitudinal mediation analysis with unobserved confounding.

    PubMed

    Shpitser, Ilya

    2013-08-01

    Questions concerning mediated causal effects are of great interest in psychology, cognitive science, medicine, social science, public health, and many other disciplines. For instance, about 60% of recent papers published in leading journals in social psychology contain at least one mediation test (Rucker, Preacher, Tormala, & Petty, 2011). Standard parametric approaches to mediation analysis employ regression models, and either the "difference method" (Judd & Kenny, 1981), more common in epidemiology, or the "product method" (Baron & Kenny, 1986), more common in the social sciences. In this article, we first discuss a known, but perhaps often unappreciated, fact that these parametric approaches are a special case of a general counterfactual framework for reasoning about causality first described by Neyman (1923) and Rubin (1924) and linked to causal graphical models by Robins (1986) and Pearl (2006). We then show a number of advantages of this framework. First, it makes the strong assumptions underlying mediation analysis explicit. Second, it avoids a number of problems present in the product and difference methods, such as biased estimates of effects in certain cases. Finally, we show the generality of this framework by proving a novel result which allows mediation analysis to be applied to longitudinal settings with unobserved confounders. PMID:23899340

  7. 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.

  8. 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

  9. 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.

  10. 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. PMID:10781883

  11. Spatial analysis of the air pollution-mortality relationship in the context of ecologic confounders.

    PubMed

    Jerrett, Michael; Burnett, Richard T; Willis, Alette; Krewski, Daniel; Goldberg, Mark S; DeLuca, Patrick; Finkelstein, Norm

    Lack of control for confounding by ecological covariates that may relate to sulfate air pollution and mortality was a key criticism of the two studies that were the focus of the Particle Reanalysis Project. To assess the validity of this criticism, we address the question: "Does sulfate air pollution exert health effects when the impact of other individual and ecologic variables thought to influence health is taken into account?" A related question arises from the possibility of autocorrelation in the mortality risks and ecologic covariates. Failure to control for autocorrelation can lead to false positive significance tests and may indicate bias resulting from a missing variable or group of variables. We control for more than 25 individual risk factors and for 20 ecologic variables representing environmental, socioeconomic, demographic, health- care, and lifestyle determinants of health in a two-stage multilevel analysis. Four modeling strategies are used to control for spatial autocorrelation. Of the 20 ecologic variables tested, only sulfate and sulfur dioxide are significant in models that incorporate spatial autocorrelation. Accounting for autocorrelation also reduces the size and certainty of the sulfate effect on mortality when compared to results generated from Cox models where independent observations are assumed. Confidence limits for the sulfate relative risk include unity in models that simultaneously control for sulfur dioxide and autocorrelation. PMID:12959842

  12. Homophily and Contagion Are Generically Confounded in Observational Social Network Studies

    PubMed Central

    Shalizi, Cosma Rohilla; Thomas, Andrew C.

    2012-01-01

    The authors consider processes on social networks that can potentially involve three factors: homophily, or the formation of social ties due to matching individual traits; social contagion, also known as social influence; and the causal effect of an individual’s covariates on his or her behavior or other measurable responses. The authors show that generically, all of these are confounded with each other. Distinguishing them from one another requires strong assumptions on the parametrization of the social process or on the adequacy of the covariates used (or both). In particular the authors demonstrate, with simple examples, that asymmetries in regression coefficients cannot identify causal effects and that very simple models of imitation (a form of social contagion) can produce substantial correlations between an individual’s enduring traits and his or her choices, even when there is no intrinsic affinity between them. The authors also suggest some possible constructive responses to these results. PMID:22523436

  13. 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

  14. [Use of causal diagrams in Epidemiology: application to a situation with confounding].

    PubMed

    Cortes, Taísa Rodrigues; Faerstein, Eduardo; Struchiner, Claudio José

    2016-08-01

    Epidemiological research still rarely uses causal diagrams, despite growing recognition of their explanatory potential. One possible reason is that many research programs involve themes in which there is a certain degree of uncertainty as to mechanisms in the processes that generate the data. In this study, the relationship between occupational stress and obesity is used as an example of the application of causal diagrams to questions related to confounding. The article presents the selection stages for variables in statistical adjustment and the derivation of a causal diagram's statistical implications. The main advantage of causal diagrams is that they explicitly reveal the respective model's underlying hypotheses, allowing critical analysis of the implications and thereby facilitating identification of sources of bias and uncertainty in the epidemiological study's results. PMID:27509550

  15. The importance of confounding in observational before-and-after studies of road safety measures.

    PubMed

    Elvik, Rune

    2002-09-01

    This paper discusses the importance of confounding in observational before-and-after studies of road safety measures. The importance of the approach taken to controlling for confounding factors is shown by means of examples. It is shown that the size of the effect on accidents attributed to a road safety measure can be profoundly affected by which confounding factors are controlled for in an evaluation study, and the way this is done. Simple before-and-after studies, not controlling for any confounding factors should never be trusted and are likely to overstate the effects of road safety measures. PMID:12214957

  16. 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.

  17. 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...

  18. 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…

  19. 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

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

    USGS Publications Warehouse

    Schoolmaster, Donald R., Jr.; 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.

  1. Fat Confounds the Observed Apparent Diffusion Coefficient in Patients with Hepatic Steatosis

    PubMed Central

    Hansmann, Jan; Hernando, Diego; Reeder, Scott B.

    2013-01-01

    Purpose Triglyceride signal contained in peaks near the water peak remain unsuppressed by conventional fat suppression techniques used in diffusion-weighted imaging (DWI). In this work we investigated the dependence of the apparent diffusion coefficient (ADC) on liver fat content and whether it is confounded by fat signal. Methods 43 patients underwent liver DWI (b=0,500s/mm2) and single-voxel MR-spectroscopy (MRS). Proton density fat-fraction (PDFF;range 0.23–34.5%) was measured from MRS. A theoretical model was developed to account for the effects of fat on observed ADC, and used to correct the ADC. Linear correlation analysis was performed to assess the relationship between PDFF and ADC before and after correction. Results Linear correlation analysis showed an inverse dependence between observed ADC and PDFF before correction (r2=0.132;p=0.017), and no dependence after correction (r2=0.033;p=0.24). Conclusion The observed decrease in ADC in patients with fatty liver is, at least in part, artifactual due to residual fat signal near the water peak. PMID:23161434

  2. Review of methods for handling confounding by cluster and informative cluster size in clustered data

    PubMed Central

    Seaman, Shaun; Pavlou, Menelaos; Copas, Andrew

    2014-01-01

    Clustered data are common in medical research. Typically, one is interested in a regression model for the association between an outcome and covariates. Two complications that can arise when analysing clustered data are informative cluster size (ICS) and confounding by cluster (CBC). ICS and CBC mean that the outcome of a member given its covariates is associated with, respectively, the number of members in the cluster and the covariate values of other members in the cluster. Standard generalised linear mixed models for cluster-specific inference and standard generalised estimating equations for population-average inference assume, in general, the absence of ICS and CBC. Modifications of these approaches have been proposed to account for CBC or ICS. This article is a review of these methods. We express their assumptions in a common format, thus providing greater clarity about the assumptions that methods proposed for handling CBC make about ICS and vice versa, and about when different methods can be used in practice. We report relative efficiencies of methods where available, describe how methods are related, identify a previously unreported equivalence between two key methods, and propose some simple additional methods. Unnecessarily using a method that allows for ICS/CBC has an efficiency cost when ICS and CBC are absent. We review tools for identifying ICS/CBC. A strategy for analysis when CBC and ICS are suspected is demonstrated by examining the association between socio-economic deprivation and preterm neonatal death in Scotland. PMID:25087978

  3. 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.

  4. 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. PMID:25860832

  5. Confounding Effects of Phase Delays on Causality Estimation

    PubMed Central

    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. PMID:23349720

  6. 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. PMID:11619819

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

    PubMed

    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

  8. 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…

  9. The MTT and Crystal Violet Assays: Potential Confounders in Nanoparticle Toxicity Testing.

    PubMed

    Almutary, A; Sanderson, B J S

    2016-07-01

    The toxicological effects of nanoparticles (NPs) on humans, animals, and environment are largely unknown. Assessment of NPs cytotoxicity depends on the choice of the test system. Due to NPs optical activity and absorption values, they can influence the classical cytotoxicity assay. Eight NPs were spiked in the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and crystal violet assays and tested with HaCaT human skin cells. The MTT assay standard curve optical density (OD) measurements were altered by the presence of trisilanol phenyl and trisilanol isooctyl polyhedral oligomeric silsesquioxane particles. The crystal violet standard curve OD measurements were significantly shifted by gold NPs, but they did not affect the MTT assay. Carbon black decreased ODs in the MTT and crystal violet assays and was localized in the cell cytoplasm. These findings strongly indicate that a careful choice of in vitro viability systems is required to avoid flawed measurement of NPs toxicity. PMID:27207930

  10. 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…

  11. Depletion of liver glutathione levels in rats: a potential confound of nose-only inhalation.

    PubMed

    Fechter, Laurence D; Nelson-Miller, Alisa; Gearhart, Caroline

    2008-07-01

    Nose-only inhalation exposure chambers offer key advantages to whole-body systems, particularly when aerosol or mixed aerosol-vapor exposures are used. Specifically, nose-only chambers provide enhanced control over the route of exposure and dose by minimizing the deposition of particles either on the subjects skin/fur or on surfaces of a whole-body exposure system. In the current series of experiments, liver, brain, and lung total glutathione (GSH) levels were assessed following either nose-only or whole-body exposures to either jet fuel or to clean, filtered air. The data were compared to untreated control subjects. Acute nose-only inhalation exposures of rats resulted in a significant depletion of liver GSH levels both in subjects that were exposed to clean, filtered air as well as those exposed to JP-8 jet fuel and to a synthetic jet fuel. Glutathione levels were not altered in lung or brain tissue. Whole-body inhalation exposure had no effect on GSH levels in any tissue for any of the treatment groups. A second experiment demonstrated that the loss of GSH did not occur if rats were anaesthetized prior to and during nose-only exposure to clean, filtered air or to mixed hydrocarbons. These data appear to be consistent with studies demonstrating depletion in liver GSH levels among rats subjected to restraint stress. Finally, the depletion of GSH that was observed in liver following a single acute exposure was reduced following five daily exposures to clean, filtered air, suggesting the possibility of habituation to restraint in the nose-only exposure chamber. The finding that placement in a nose-only exposure chamber per se yields liver GSH depletion raises the possibility of an interaction between this mode of toxicant exposure and the toxicological effects of certain inhaled test substances. PMID:18645729

  12. 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

  13. 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).

  14. Familial Confounding of the Association between Maternal Smoking During Pregnancy and ADHD in Offspring

    PubMed Central

    Skoglund, Charlotte; Chen, Qi; D´Onofrio, Brian M; Lichtenstein, Paul; Larsson, Henrik

    2013-01-01

    Background Maternal Smoking During Pregnancy (SDP) has consistently been associated with increased risk of attention deficit hyperactivity disorder (ADHD) in offspring, but recent studies indicate that this association might be due to unmeasured familial confounding. Methods A total of 813 030 individuals born in Sweden between 1992 and 2000 were included in this nationwide population based cohort study. Data on maternal SDP and ADHD diagnosis were obtained from national registers and patients were followed up from the age of 3 to the end of 2009. Hazard Ratios (HRs) were estimated using stratified Cox regression models. Cousin and sibling data were used to control for unmeasured familial confounding. Results At the population level maternal SDP predicted ADHD in offspring (HRModerateSDP=1.89; HRHighSDP=2.50). This estimate gradually attenuated towards the null when adjusting for measured confounders (HRModerateSDP=1.62; HRHighSDP=2.04), unmeasured confounders shared within the extended family (i.e., cousin comparison) (HRModerateSDP= 1.45; HRHighSDP=1.69), and unmeasured confounders within the nuclear family (i.e., sibling comparison) (HRModerateSDP=0.88; HRHighSDP=0.84). Conclusions Our results suggest that the association between maternal SDP and offspring ADHD are due to unmeasured familial confounding. PMID:25359172

  15. Structural equation modeling versus marginal structural modeling for assessing mediation in the presence of posttreatment confounding.

    PubMed

    Moerkerke, Beatrijs; Loeys, Tom; Vansteelandt, Stijn

    2015-06-01

    Inverse probability weighting for marginal structural models has been suggested as a strategy to estimate the direct effect of a treatment or exposure on an outcome in studies where the effect of mediator on outcome is subject to posttreatment confounding. This type of confounding, whereby confounders of the effect of mediator on outcome are themselves affected by the exposure, complicates mediation analyses and necessitates apt analysis strategies. In this article, we contrast the inverse probability weighting approach with the traditional path analysis approach to mediation analysis. We show that in a particular class of linear models, adjustment for posttreatment confounding can be realized via a fairly standard modification of the traditional path analysis approach. The resulting approach is simpler; by avoiding inverse probability weighting, it moreover results in direct effect estimators with smaller finite sample bias and greater precision. We further show that a particular variant of the G-estimation approach from the causal inference literature is equivalent with the path analysis approach in simple linear settings but is more generally applicable in settings with interactions and/or noncontinuous mediators and confounders. We conclude that the use of inverse probability weighting for marginal structural models to adjust for posttreatment confounding in mediation analysis is primarily indicated in nonlinear models for the outcome. PMID:25751514

  16. Is the Association between General Cognitive Ability and Violent Crime Caused by Family-Level Confounders?

    PubMed Central

    Frisell, Thomas; Pawitan, Yudi; Långström, Niklas

    2012-01-01

    Background Research has consistently found lower cognitive ability to be related to increased risk for violent and other antisocial behaviour. Since this association has remained when adjusting for childhood socioeconomic position, ethnicity, and parental characteristics, it is often assumed to be causal, potentially mediated through school adjustment problems and conduct disorder. Socioeconomic differences are notoriously difficult to quantify, however, and it is possible that the association between intelligence and delinquency suffer substantial residual confounding. Methods We linked longitudinal Swedish total population registers to study the association of general cognitive ability (intelligence) at age 18 (the Conscript Register, 1980–1993) with the incidence proportion of violent criminal convictions (the Crime Register, 1973–2009), among all men born in Sweden 1961–1975 (N = 700,514). Using probit regression, we controlled for measured childhood socioeconomic variables, and further employed sibling comparisons (family pedigree data from the Multi-Generation Register) to adjust for shared familial characteristics. Results Cognitive ability in early adulthood was inversely associated to having been convicted of a violent crime (β = −0.19, 95% CI: −0.19; −0.18), the association remained when adjusting for childhood socioeconomic factors (β = −0.18, 95% CI: −0.18; −0.17). The association was somewhat lower within half-brothers raised apart (β = −0.16, 95% CI: −0.18; −0.14), within half-brothers raised together (β = −0.13, 95% CI: (−0.15; −0.11), and lower still in full-brother pairs (β = −0.10, 95% CI: −0.11; −0.09). The attenuation among half-brothers raised together and full brothers was too strong to be attributed solely to attenuation from measurement error. Discussion Our results suggest that the association between general cognitive ability and violent criminality is confounded partly by

  17. 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.

  18. 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

  19. 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

  20. 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.

  1. 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

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

    PubMed

    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

  3. 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.

  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. 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

  6. Using instrumental variables to estimate a Cox's proportional hazards regression subject to additive confounding

    PubMed Central

    Tosteson, Tor D.; Morden, Nancy E.; Stukel, Therese A.; O'Malley, A. James

    2014-01-01

    The estimation of treatment effects is one of the primary goals of statistics in medicine. Estimation based on observational studies is subject to confounding. Statistical methods for controlling bias due to confounding include regression adjustment, propensity scores and inverse probability weighted estimators. These methods require that all confounders are recorded in the data. The method of instrumental variables (IVs) can eliminate bias in observational studies even in the absence of information on confounders. We propose a method for integrating IVs within the framework of Cox's proportional hazards model and demonstrate the conditions under which it recovers the causal effect of treatment. The methodology is based on the approximate orthogonality of an instrument with unobserved confounders among those at risk. We derive an estimator as the solution to an estimating equation that resembles the score equation of the partial likelihood in much the same way as the traditional IV estimator resembles the normal equations. To justify this IV estimator for a Cox model we perform simulations to evaluate its operating characteristics. Finally, we apply the estimator to an observational study of the effect of coronary catheterization on survival. PMID:25506259

  7. 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

  8. Randomly Accountable

    ERIC Educational Resources Information Center

    Kane, Thomas J.; Staiger, Douglas O.; Geppert, Jeffrey

    2002-01-01

    The accountability debate tends to devolve into a battle between the pro-testing and anti-testing crowds. When it comes to the design of a school accountability system, the devil is truly in the details. A well-designed accountability plan may go a long way toward giving school personnel the kinds of signals they need to improve performance.…

  9. School Accountability.

    ERIC Educational Resources Information Center

    Evers, Williamson M., Ed.; Walberg, Herbert J., Ed.

    This book presents the perspectives of experts from the fields of history, economics, political science, and psychology on what is known about accountability, what still needs to be learned, what should be done right now, and what should be avoided in devising accountability systems. The common myths about accountability are dispelled and how it…

  10. Colorful Accounting

    ERIC Educational Resources Information Center

    Warrick, C. Shane

    2006-01-01

    As instructors of accounting, we should take an abstract topic (at least to most students) and connect it to content known by students to help increase the effectiveness of our instruction. In a recent semester, ordinary items such as colors, a basketball, and baseball were used to relate the subject of accounting. The accounting topics of account…

  11. Utility of ethological analysis to overcome locomotor confounds in elevated maze models of anxiety.

    PubMed

    Weiss, S M; Wadsworth, G; Fletcher, A; Dourish, C T

    1998-01-01

    The elevated plus-maze is a commonly used model to identify putative anxiolytic and anxiogenic drugs. However, the validity of elevated plus-maze and other recently developed variants such as the elevated zero-maze has recently been questioned on the grounds that both the reference anxiolytic drug chlordiazepoxide and the psychostimulant d-amphetamine increase open arm exploration and stimulate locomotor activity. These findings suggest that measures of "anxiety" in the elevated maze cannot be adequately dissociated from simple changes in locomotor activity, which may confound the interpretation of results obtained using these models. A variety of approaches to assess drug effects on locomotor activity in the elevated maze have been suggested, including the use of total and closed arm entries, as well as supplementary tests such as exploration of the holeboard apparatus. However, all these approaches utilise the measurement of exploration in a novel environment, and as such, could potentially be influenced by either changes in anxiety or locomotor activity. Recently, it has been shown that ethological measures of "risk assessment", such as stretched-attend postures and head-dipping, are sensitive indicators of drug-effects in the elevated maze. The present study assessed the utility of ethological analysis in dissociating locomotor activity from "anxiety" by comparing the effects of d-amphetamine to those of chlordiazepoxide in the rat elevated zero-maze. The results showed that both chlordiazepoxide and d-amphetamine increase the amount of time spent in the open arms and reduce "risk assessment" without increasing line crossing or rearing. These results confirm that under certain test conditions, psychostimulants are capable of producing "false-positives" in elevated maze models, and that both traditional methods and the ethological measures used in this study fail to unequivocally dissociate drug effects on anxiety from effects on locomotor activity. Further

  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. Sharp sensitivity bounds for mediation under unmeasured mediator-outcome confounding

    PubMed Central

    Ding, Peng; Vanderweele, Tyler J.

    2016-01-01

    It is often of interest to decompose the total effect of an exposure into a component that acts on the outcome through some mediator and a component that acts independently through other pathways. Said another way, we are interested in the direct and indirect effects of the exposure on the outcome. Even if the exposure is randomly assigned, it is often infeasible to randomize the mediator, leaving the mediator-outcome confounding not fully controlled. We develop a sensitivity analysis technique that can bound the direct and indirect effects without parametric assumptions about the unmeasured mediator-outcome confounding.

  14. 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

  15. Removing the influence of feature repetitions on the congruency sequence effect: why regressing out confounds from a nested design will often fall short.

    PubMed

    Schmidt, James R; De Schryver, Maarten; Weissman, Daniel H

    2014-12-01

    This article illustrates a shortcoming of using regression to control for confounds in nested designs. As an example, we consider the congruency sequence effect, which is the observation that the congruency effect in distractor interference (e.g., Stroop) tasks is smaller following incongruent as compared with congruent trials. The congruency sequence effect is often interpreted as indexing conflict adaptation: a relative increase of attention to the target following incongruent trials. However, feature repetitions across consecutive trials can complicate this interpretation. To control for this confound, the standard procedure is to delete all trials with a stimulus or response repetition and analyze the remaining trials. Notebaert and Verguts (2007) present an alternative method that allows researchers to use all trials. Specifically, they employ multiple regression to model conflict adaptation independent of feature repetitions. We show here that this approach fails to account for certain feature repetition effects. Furthermore, modeling these additional effects is typically not possible because of an upper bound on the number of degrees of freedom in the experiment. These findings have important implications for future investigations of conflict adaptation and, more broadly, for all researchers who attempt to regress out confounds in nested designs. PMID:25419672

  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. 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

  18. Consistent causal effect estimation under dual misspecification and implications for confounder selection procedures

    PubMed Central

    Gruber, Susan; van der Laan, Mark J

    2014-01-01

    In a previously published article in this journal, Vansteeland et al. [Stat Methods Med Res. Epub ahead of print 12 November 2010. DOI: 10.1177/0962280210387717] address confounder selection in the context of causal effect estimation in observational studies. They discuss several selection strategies and propose a procedure whose performance is guided by the quality of the exposure effect estimator. The authors note that when a particular linearity condition is met, consistent estimation of the target parameter can be achieved even under dual misspecification of models for the association of confounders with exposure and outcome and demonstrate the performance of their procedure relative to other estimators when this condition holds. Our earlier published work on collaborative targeted minimum loss based learning provides a general theoretical framework for effective confounder selection that explains the findings of Vansteelandt et al. and underscores the appropriateness of their suggestions that a confounder selection procedure should be concerned with directly targeting the quality of the estimate and that desirable estimators produce valid confidence intervals and are robust to dual misspecification. PMID:22368176

  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. PMID:26943010

  1. 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

  2. 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

  3. Health Effects of Lesion Localization in Multiple Sclerosis: Spatial Registration and Confounding Adjustment

    PubMed Central

    Eloyan, Ani; Shou, Haochang; Shinohara, Russell T.; Sweeney, Elizabeth M.; Nebel, Mary Beth; Cuzzocreo, Jennifer L.; Calabresi, Peter A.; Reich, Daniel S.; Lindquist, Martin A.; Crainiceanu, Ciprian M.

    2014-01-01

    Brain lesion localization in multiple sclerosis (MS) is thought to be associated with the type and severity of adverse health effects. However, several factors hinder statistical analyses of such associations using large MRI datasets: 1) spatial registration algorithms developed for healthy individuals may be less effective on diseased brains and lead to different spatial distributions of lesions; 2) interpretation of results requires the careful selection of confounders; and 3) most approaches have focused on voxel-wise regression approaches. In this paper, we evaluated the performance of five registration algorithms and observed that conclusions regarding lesion localization can vary substantially with the choice of registration algorithm. Methods for dealing with confounding factors due to differences in disease duration and local lesion volume are introduced. Voxel-wise regression is then extended by the introduction of a metric that measures the distance between a patient-specific lesion mask and the population prevalence map. PMID:25233361

  4. 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

  5. Clinical and methodological confounders in assessing the cerebellar cognitive affective syndrome in adult patients with posterior fossa tumours.

    PubMed

    Omar, Dashne; Ryan, Tracy; Carson, Alan; Bak, Thomas H; Torrens, Lorna; Whittle, Ian

    2014-12-01

    The cerebellar cognitive affective syndrome (CCAS) was first described by Schmahmann and Sherman as a constellation of symptoms including dysexecutive syndrome, spatial cognitive deficit, linguistic deficits and behavioural abnormalities in patients with a lesion in the cerebellum with otherwise normal brain. Neurosurgical patients with cerebellar tumours constitute one of the cohorts in which the CCAS has been described. In this paper, we present a critical review of the literature of this syndrome in neurosurgical patients. Thereafter, we present a prospective clinical study of 10 patients who underwent posterior fossa tumour resection and had a detailed post-operative neuropsychological, neuropsychiatric and neuroradiological assessment. Because our findings revealed a large number of perioperative neuroradiological confounding variables, we reviewed the neuroimaging of a further 20 patients to determine their prevalence. Our literature review revealed that study design, methodological quality and sometimes both diagnostic criteria and findings were inconsistent. The neuroimaging study (pre-operative, n = 10; post-operative, n = 10) showed very frequent neuroradiological confounding complications (e.g. hydrocephalus; brainstem compression; supratentorial lesions and post-operative subdural hygroma); the impact of such features had largely been ignored in the literature. Findings from our clinical study showed various degree of deficits in neuropsychological testing (n = 1, memory; n = 3, verbal fluency; n = 3, attention; n = 2, spatial cognition deficits; and n = 1, behavioural changes), but no patient had full-blown features of CCAS. Our study, although limited, finds no robust evidence of the CCAS following surgery. This and our literature review highlight a need for guidelines regarding study design and methodology when attempting to evaluate neurosurgical cases with regard to the potential CCAS. PMID:24881640

  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. The confounding effect of cryptic relatedness for environmental risks of systolic blood pressure on cohort studies

    PubMed Central

    Shibata, Kyoko; Hozawa, Atsushi; Tamiya, Gen; Ueki, Masao; Nakamura, Tomohiro; Narimatsu, Hiroto; Kubota, Isao; Ueno, Yoshiyuki; Kato, Takeo; Yamashita, Hidetoshi; Fukao, Akira; Kayama, Takamasa

    2013-01-01

    The impact of cryptic relatedness (CR) on genomic association studies is well studied and known to inflate false-positive rates as reported by several groups. In contrast, conventional epidemiological studies for environmental risks, the confounding effect of CR is still uninvestigated. In this study, we investigated the confounding effect of unadjusted CR among a rural cohort in the relationship between environmental risk factors (body mass index, smoking status, alcohol consumption) and systolic blood pressure. We applied the methods of population-based whole-genome association studies for the analysis of the genome-wide single nucleotide polymorphism data in 1622 subjects, and detected 20.2% CR in this cohort population. In the case of the sample size, approximately 1000, the ratio of CR to the population was 20.2%, the population prevalence 25%, the prevalence in the CR 26%, heritability for liability 14.3% and prevalence in the subpopulation without CR 26%, the difference of estimated regression coefficient between samples with and without CR was not significant (P-value = 0.55). On the other hand, in another case with approximately >20% heritability for liability, we showed that confounding due to CR biased the estimation of exposure effects. PMID:24498600

  8. The importance of scale for spatial-confounding bias and precision of spatial regression estimators

    PubMed Central

    Paciorek, Christopher J

    2010-01-01

    Residuals in regression models are often spatially correlated. Prominent examples include studies in environmental epidemiology to understand the chronic health effects of pollutants. I consider the effects of residual spatial structure on the bias and precision of regression coefficients, developing a simple framework in which to understand the key issues and derive informative analytic results. When unmeasured confounding introduces spatial structure into the residuals, regression models with spatial random effects and closely-related models such as kriging and penalized splines are biased, even when the residual variance components are known. Analytic and simulation results show how the bias depends on the spatial scales of the covariate and the residual: one can reduce bias by fitting a spatial model only when there is variation in the covariate at a scale smaller than the scale of the unmeasured confounding. I also discuss how the scales of the residual and the covariate affect efficiency and uncertainty estimation when the residuals are independent of the covariate. In an application on the association between black carbon particulate matter air pollution and birth weight, controlling for large-scale spatial variation appears to reduce bias from unmeasured confounders, while increasing uncertainty in the estimated pollution effect. PMID:21528104

  9. The confounding effect of cryptic relatedness for environmental risks of systolic blood pressure on cohort studies.

    PubMed

    Shibata, Kyoko; Hozawa, Atsushi; Tamiya, Gen; Ueki, Masao; Nakamura, Tomohiro; Narimatsu, Hiroto; Kubota, Isao; Ueno, Yoshiyuki; Kato, Takeo; Yamashita, Hidetoshi; Fukao, Akira; Kayama, Takamasa

    2013-05-01

    The impact of cryptic relatedness (CR) on genomic association studies is well studied and known to inflate false-positive rates as reported by several groups. In contrast, conventional epidemiological studies for environmental risks, the confounding effect of CR is still uninvestigated. In this study, we investigated the confounding effect of unadjusted CR among a rural cohort in the relationship between environmental risk factors (body mass index, smoking status, alcohol consumption) and systolic blood pressure. We applied the methods of population-based whole-genome association studies for the analysis of the genome-wide single nucleotide polymorphism data in 1622 subjects, and detected 20.2% CR in this cohort population. In the case of the sample size, approximately 1000, the ratio of CR to the population was 20.2%, the population prevalence 25%, the prevalence in the CR 26%, heritability for liability 14.3% and prevalence in the subpopulation without CR 26%, the difference of estimated regression coefficient between samples with and without CR was not significant (P-value = 0.55). On the other hand, in another case with approximately >20% heritability for liability, we showed that confounding due to CR biased the estimation of exposure effects. PMID:24498600

  10. Sensitivity analysis for direct and indirect effects in the presence of exposure-induced mediator-outcome confounders

    PubMed Central

    Chiba, Yasutaka

    2014-01-01

    Questions of mediation are often of interest in reasoning about mechanisms, and methods have been developed to address these questions. However, these methods make strong assumptions about the absence of confounding. Even if exposure is randomized, there may be mediator-outcome confounding variables. Inference about direct and indirect effects is particularly challenging if these mediator-outcome confounders are affected by the exposure because in this case these effects are not identified irrespective of whether data is available on these exposure-induced mediator-outcome confounders. In this paper, we provide a sensitivity analysis technique for natural direct and indirect effects that is applicable even if there are mediator-outcome confounders affected by the exposure. We give techniques for both the difference and risk ratio scales and compare the technique to other possible approaches. PMID:25580387

  11. 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…

  12. 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:…

  13. 12 CFR 707.4 - Account disclosures.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 6 2011-01-01 2011-01-01 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...

  14. Pre-Analytical Parameters Affecting Vascular Endothelial Growth Factor Measurement in Plasma: Identifying Confounders

    PubMed Central

    Walz, Johanna M.; Boehringer, Daniel; Deissler, Heidrun L.; Faerber, Lothar; Goepfert, Jens C.; Heiduschka, Peter; Kleeberger, Susannah M.; Klettner, Alexa; Krohne, Tim U.; Schneiderhan-Marra, Nicole; Ziemssen, Focke; Stahl, Andreas

    2016-01-01

    Background Vascular endothelial growth factor-A (VEGF-A) is intensively investigated in various medical fields. However, comparing VEGF-A measurements is difficult because sample acquisition and pre-analytic procedures differ between studies. We therefore investigated which variables act as confounders of VEGF-A measurements. Methods Following a standardized protocol, blood was taken at three clinical sites from six healthy participants (one male and one female participant at each center) twice one week apart. The following pre-analytical parameters were varied in order to analyze their impact on VEGF-A measurements: analyzing center, anticoagulant (EDTA vs. PECT / CTAD), cannula (butterfly vs. neonatal), type of centrifuge (swing-out vs. fixed-angle), time before and after centrifugation, filling level (completely filled vs. half-filled tubes) and analyzing method (ELISA vs. multiplex bead array). Additionally, intrapersonal variations over time and sex differences were explored. Statistical analysis was performed using a linear regression model. Results The following parameters were identified as statistically significant independent confounders of VEGF-A measurements: analyzing center, anticoagulant, centrifuge, analyzing method and sex of the proband. The following parameters were no significant confounders in our data set: intrapersonal variation over one week, cannula, time before and after centrifugation and filling level of collection tubes. Conclusion VEGF-A measurement results can be affected significantly by the identified pre-analytical parameters. We recommend the use of CTAD anticoagulant, a standardized type of centrifuge and one central laboratory using the same analyzing method for all samples. PMID:26730574

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

    PubMed

    Li, L; Kleinman, K; Gillman, M W

    2014-12-01

    We implemented six 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 body mass index (BMI) z-score at 3 years and two separate dichotomous exposure measures: exclusive breastfeeding v. formula only (n=437) and cesarean section v. 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 (204-276) 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

  16. 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

  17. 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

  18. Offspring ADHD as a Risk Factor for Parental Marital Problems: Controls for Genetic and Environmental Confounds

    PubMed Central

    Schermerhorn, Alice C.; D’Onofrio, Brian M.; Slutske, Wendy S.; Emery, Robert E.; Turkheimer, Eric; Harden, K. Paige; Heath, Andrew C.; Martin, Nicholas G.

    2013-01-01

    Background Previous studies have found that child attention-deficit/hyperactivity disorder (ADHD) is associated with more parental marital problems. The reasons for this association are unclear, however. The association might be due to genetic or environmental confounds that contribute to both marital problems and ADHD. Method Data were drawn from the Australian Twin Registry, including 1296 individual twins, their spouses, and offspring. We studied adult twins who were discordant for offspring ADHD. Using a discordant twin pairs design, we examined the extent to which genetic and environmental confounds, as well as measured parental and offspring characteristics, explain the ADHD-marital problems association. Results Offspring ADHD predicted parental divorce and marital conflict. The associations were also robust when comparing differentially exposed identical twins to control for unmeasured genetic and environmental factors, when controlling for measured maternal and paternal psychopathology, when restricting the sample based on timing of parental divorce and ADHD onset, and when controlling for other forms of offspring psychopathology. Each of these controls rules out alternative explanations for the association. Conclusion The results of the current study converge with those of prior research in suggesting that factors directly associated with offspring ADHD increase parental marital problems. PMID:22958575

  19. Low HbA1c and Increased Mortality Risk-is Frailty a Confounding Factor?

    PubMed Central

    Abdelhafiz, Ahmed H; Sinclair, Alan J

    2015-01-01

    Diabetes mellitus is increasingly becoming an older person disease due to the increased survival and aging of the population. Previous studies which showed benefits of tight glycemic control and a linear relationship between HbA1c and mortality have largely included younger patients newly diagnosed with diabetes and with less comorbidities. Recent studies, which included older population with diabetes, have shown a U-shaped relationship of increased mortality associated with low HbA1c. The mechanism of such relationship is unclear. There was no direct causal link between low HbA1c and mortality. It appears that malnutrition, inflammation and functional decline are characteristics shared by the populations that showed increased mortality and low HbA1c. In these studies functional status, disability or frailty was not routinely measured. Therefore, although adjustment for comorbidities was made there may be a residual confounding by unmeasured factors such as frailty. Thus, frailty or decline in functional reserve may be the main confounding factor explaining the relationship between increased mortality risk and low HbA1c. PMID:26236548

  20. Does environmental confounding mask pleiotropic effects of a multiple sclerosis susceptibility variant on vitamin D in psychosis?

    PubMed Central

    Iyegbe, Conrad O; Acharya, Anita; Lally, John; Gardner-Sood, Poonam; Smith, Louise S; Smith, Shubulade; Murray, Robin; Howes, Oliver; Gaughran, Fiona

    2015-01-01

    Background: This work addresses the existing and emerging evidence of overlap within the environmental and genetic profiles of multiple sclerosis (MS) and schizophrenia. Aims: To investigate whether a genetic risk factor for MS (rs703842), whose variation is indicative of vitamin D status in the disorder, could also be a determinant of vitamin D status in chronic psychosis patients. Methods: A cohort of 224 chronic psychosis cases was phenotyped and biologically profiled. The relationship between rs703842 and physiological vitamin D status in the blood plasma was assessed by logistic regression. Deficiency was defined as a blood plasma concentration below 10 ng/µl. Potential environmental confounders of the vitamin D status were considered as part of the analysis. Results: We report suggestive evidence of an association with vitamin D status in established psychosis (ßstandardized=0.51, P=0.04). The logistic model fit significantly benefited from controlling for body mass index, depression and ethnicity (χ2=91.7; 2 degrees of freedom (df); P=1.2×1020). Conclusions: The results suggest that, in addition to lifestyle changes that accompany the onset of illness, vitamin D dysregulation in psychosis has a genetic component that links into MS. Further, comprehensive studies are needed to evaluate this prospect. PMID:27336042

  1. Confounding factors in HGT detection: statistical error, coalescent effects, and multiple solutions.

    PubMed

    Than, Cuong; Ruths, Derek; Innan, Hideki; Nakhleh, Luay

    2007-05-01

    Prokaryotic organisms share genetic material across species boundaries by means of a process known as horizontal gene transfer (HGT). This process has great significance for understanding prokaryotic genome diversification and unraveling their complexities. Phylogeny-based detection of HGT is one of the most commonly used methods for this task, and is based on the fundamental fact that HGT may cause gene trees to disagree with one another, as well as with the species phylogeny. Using these methods, we can compare gene and species trees, and infer a set of HGT events to reconcile the differences among these trees. In this paper, we address three factors that confound the detection of the true HGT events, including the donors and recipients of horizontally transferred genes. First, we study experimentally the effects of error in the estimated gene trees (statistical error) on the accuracy of inferred HGT events. Our results indicate that statistical error leads to overestimation of the number of HGT events, and that HGT detection methods should be designed with unresolved gene trees in mind. Second, we demonstrate, both theoretically and empirically, that based on topological comparison alone, the number of HGT scenarios that reconcile a pair of species/gene trees may be exponential. This number may be reduced when branch lengths in both trees are estimated correctly. This set of results implies that in the absence of additional biological information, and/or a biological model of how HGT occurs, multiple HGT scenarios must be sought, and efficient strategies for how to enumerate such solutions must be developed. Third, we address the issue of lineage sorting, how it confounds HGT detection, and how to incorporate it with HGT into a single stochastic framework that distinguishes between the two events by extending population genetics theories. This result is very important, particularly when analyzing closely related organisms, where coalescent effects may not be

  2. Cascaded discrimination of normal, abnormal, and confounder classes in histopathology: Gleason grading of prostate cancer

    PubMed Central

    2012-01-01

    Background Automated classification of histopathology involves identification of multiple classes, including benign, cancerous, and confounder categories. The confounder tissue classes can often mimic and share attributes with both the diseased and normal tissue classes, and can be particularly difficult to identify, both manually and by automated classifiers. In the case of prostate cancer, they may be several confounding tissue types present in a biopsy sample, posing as major sources of diagnostic error for pathologists. Two common multi-class approaches are one-shot classification (OSC), where all classes are identified simultaneously, and one-versus-all (OVA), where a “target” class is distinguished from all “non-target” classes. OSC is typically unable to handle discrimination of classes of varying similarity (e.g. with images of prostate atrophy and high grade cancer), while OVA forces several heterogeneous classes into a single “non-target” class. In this work, we present a cascaded (CAS) approach to classifying prostate biopsy tissue samples, where images from different classes are grouped to maximize intra-group homogeneity while maximizing inter-group heterogeneity. Results We apply the CAS approach to categorize 2000 tissue samples taken from 214 patient studies into seven classes: epithelium, stroma, atrophy, prostatic intraepithelial neoplasia (PIN), and prostate cancer Gleason grades 3, 4, and 5. A series of increasingly granular binary classifiers are used to split the different tissue classes until the images have been categorized into a single unique class. Our automatically-extracted image feature set includes architectural features based on location of the nuclei within the tissue sample as well as texture features extracted on a per-pixel level. The CAS strategy yields a positive predictive value (PPV) of 0.86 in classifying the 2000 tissue images into one of 7 classes, compared with the OVA (0.77 PPV) and OSC approaches (0.76 PPV

  3. gespeR: a statistical model for deconvoluting off-target-confounded RNA interference screens.

    PubMed

    Schmich, Fabian; Szczurek, Ewa; Kreibich, Saskia; Dilling, Sabrina; Andritschke, Daniel; Casanova, Alain; Low, Shyan Huey; Eicher, Simone; Muntwiler, Simone; Emmenlauer, Mario; Rämö, Pauli; Conde-Alvarez, Raquel; von Mering, Christian; Hardt, Wolf-Dietrich; Dehio, Christoph; Beerenwinkel, Niko

    2015-01-01

    Small interfering RNAs (siRNAs) exhibit strong off-target effects, which confound the gene-level interpretation of RNA interference screens and thus limit their utility for functional genomics studies. Here, we present gespeR, a statistical model for reconstructing individual, gene-specific phenotypes. Using 115,878 siRNAs, single and pooled, from three companies in three pathogen infection screens, we demonstrate that deconvolution of image-based phenotypes substantially improves the reproducibility between independent siRNA sets targeting the same genes. Genes selected and prioritized by gespeR are validated and shown to constitute biologically relevant components of pathogen entry mechanisms and TGF-β signaling. gespeR is available as a Bioconductor R-package. PMID:26445817

  4. 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

  5. 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

  6. Adolescent Alcohol Abuse and Adverse Adult Outcomes: Evaluating Confounds with Drinking-Discordant Twins

    PubMed Central

    Rose, Richard J.; Winter, Torsten; Viken, Richard J.; Kaprio, Jaakko

    2014-01-01

    Background Adolescent alcohol abuse is associated with adverse outcomes in early adulthood, but differences in familial status and structure and household and community environments correlate with both adolescent drinking and adverse adult outcomes and may explain their association. We studied drinking-discordant twin pairs to evaluate such confounds to ask: Will between-family associations replicate in within-family comparisons? Methods With longitudinal data from > 3,000 Finnish twins, we associated drinking problems at age 18½ with 13 outcomes assessed at age 25; included were sustained substance abuse, poor health, physical symptoms, early coital debut, multiple sexual partners, life dissatisfaction, truncated education, and financial problems. We assessed associations among twins as individuals with linear regression adjusted for correlated observations; within-family analyses of discordant twin pairs followed, comparing paired means for adult outcomes among co-twins discordant for adolescent problem drinking. Defining discordance by extreme scores on self-reported problem drinking at age 18½ permitted parallel analyses of twins as individuals and discordant twin pairs. Alternate definitions of pair-wise discordance and difference score correlations across the entire twin sample yielded supplementary analyses. Results All individual associations were highly significant for all definitions of discordance we employed. Depending on definitions of discordance, 11 to 13 comparisons of all drinking-discordant twin pairs and 3 to 6 comparisons of discordant monozygotic twin pairs replicated between-family associations. For most outcomes, effect size attenuated from individual level analysis to that within discordant MZ twin pairs providing evidence of partial confounding in associations reported in earlier research. The exception was the General Health Questionnaire; at age 25, GHQ-12 had equivalent associations with age 18½ RAPI across all comparisons

  7. Depression and Physical Inactivity as Confounding the Effect of Obesity on Atrial Fibrillation.

    PubMed

    Garimella, Roja S; Sears, Samuel F; Gehi, Anil K

    2016-06-01

    Obesity is associated with an increased likelihood for the development of atrial fibrillation (AF) and with worsened AF symptom severity. However, other factors that are correlated with obesity may confound or mediate the relation of obesity with AF symptom severity. The purpose of this study was to determine if depression and physical inactivity may confound the association of obesity and AF symptom severity. Health status and demographic data were captured by questionnaire for 332 outpatients with documented AF. Weight/height was measured and body mass index (kg/m(2)) calculated. Recent depression symptom severity was assessed using the Patient Health Questionnaire-9 questionnaire. Physical activity during the last month was assessed by questionnaire. AF symptom severity was assessed using the University of Toronto AF Severity scale. Multivariate linear regression was used to evaluate which factors were associated with AF symptom severity. Obesity in patients with AF is associated with increased depression severity. In bivariate analysis, increasing body mass index (p = 0.001), lower levels of physical activity (p <0.001), and more severe depression (p <0.001) were associated with worsened AF symptom severity. In multivariate analysis, only physical activity and depression persisted as significant predictors of AF symptom severity. In conclusion, although obesity likely contributes to the substrate predisposing to the development of AF, other factors may contribute to or mediate the worsened AF symptoms associated with obesity. Depression symptoms and physical inactivity, factors closely correlated with obesity, may exacerbate symptoms in patients with AF. PMID:27067618

  8. Correlation between heart rate variability and pulmonary function adjusted by confounding factors in healthy adults.

    PubMed

    Bianchim, M S; Sperandio, E F; Martinhão, G S; Matheus, A C; Lauria, V T; da Silva, R P; Spadari, R C; Gagliardi, A R T; Arantes, R L; Romiti, M; Dourado, V Z

    2016-03-01

    The autonomic nervous system maintains homeostasis, which is the state of balance in the body. That balance can be determined simply and noninvasively by evaluating heart rate variability (HRV). However, independently of autonomic control of the heart, HRV can be influenced by other factors, such as respiratory parameters. Little is known about the relationship between HRV and spirometric indices. In this study, our objective was to determine whether HRV correlates with spirometric indices in adults without cardiopulmonary disease, considering the main confounders (e.g., smoking and physical inactivity). In a sample of 119 asymptomatic adults (age 20-80 years), we evaluated forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1). We evaluated resting HRV indices within a 5-min window in the middle of a 10-min recording period, thereafter analyzing time and frequency domains. To evaluate daily physical activity, we instructed participants to use a triaxial accelerometer for 7 days. Physical inactivity was defined as <150 min/week of moderate to intense physical activity. We found that FVC and FEV1, respectively, correlated significantly with the following aspects of the RR interval: standard deviation of the RR intervals (r =0.31 and 0.35), low-frequency component (r =0.38 and 0.40), and Poincaré plot SD2 (r =0.34 and 0.36). Multivariate regression analysis, adjusted for age, sex, smoking, physical inactivity, and cardiovascular risk, identified the SD2 and dyslipidemia as independent predictors of FVC and FEV1 (R2=0.125 and 0.180, respectively, for both). We conclude that pulmonary function is influenced by autonomic control of cardiovascular function, independently of the main confounders. PMID:26840706

  9. 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

  10. Correlation between heart rate variability and pulmonary function adjusted by confounding factors in healthy adults

    PubMed Central

    Bianchim, M.S.; Sperandio, E.F.; Martinhão, G.S.; Matheus, A.C.; Lauria, V.T.; da Silva, R.P.; Spadari, R.C.; Gagliardi, A.R.T.; Arantes, R.L.; Romiti, M.; Dourado, V.Z.

    2016-01-01

    The autonomic nervous system maintains homeostasis, which is the state of balance in the body. That balance can be determined simply and noninvasively by evaluating heart rate variability (HRV). However, independently of autonomic control of the heart, HRV can be influenced by other factors, such as respiratory parameters. Little is known about the relationship between HRV and spirometric indices. In this study, our objective was to determine whether HRV correlates with spirometric indices in adults without cardiopulmonary disease, considering the main confounders (e.g., smoking and physical inactivity). In a sample of 119 asymptomatic adults (age 20-80 years), we evaluated forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1). We evaluated resting HRV indices within a 5-min window in the middle of a 10-min recording period, thereafter analyzing time and frequency domains. To evaluate daily physical activity, we instructed participants to use a triaxial accelerometer for 7 days. Physical inactivity was defined as <150 min/week of moderate to intense physical activity. We found that FVC and FEV1, respectively, correlated significantly with the following aspects of the RR interval: standard deviation of the RR intervals (r =0.31 and 0.35), low-frequency component (r =0.38 and 0.40), and Poincaré plot SD2 (r =0.34 and 0.36). Multivariate regression analysis, adjusted for age, sex, smoking, physical inactivity, and cardiovascular risk, identified the SD2 and dyslipidemia as independent predictors of FVC and FEV1 (R 2=0.125 and 0.180, respectively, for both). We conclude that pulmonary function is influenced by autonomic control of cardiovascular function, independently of the main confounders. PMID:26840706

  11. 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

  12. 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.

  13. 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…

  14. 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

  15. 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

  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. 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

  18. 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

  19. Common confounders of dietary elimination trials contain the antigens soy, pork, and beef.

    PubMed

    Parr, Jacqueline M; Remillard, Rebecca L

    2014-01-01

    Nutritionists and dermatologists recommend avoiding flavored over-the-counter (OTC) products and medications during dietary elimination trials because those products are thought to contain common proteins that may confound the trial. The objective of this study was to determine if there are soy, pork, and beef antigens in flavored OTC products and medications and, if so, could those antigens be identified. Seven products, three OTC products and four veterinary therapeutics, were tested using enzyme-linked immunosorbent assays (ELISA) for the presence of soy, pork, and beef antigens, in addition to positive and negative controls. All OTC test products produced ELISA results in agreement with their ingredient lists. ELISA testing of veterinary therapeutic products did not agree with either their ingredient lists or product inserts because of other ingredients not listed. Veterinarians should contact manufacturers of oral therapeutics prior to prescribing them to determine other ingredients. Likewise, manufacturers should be contacted regarding "natural and artificial flavors." Lastly, gelatin capsules may contain either beef or pork proteins and should not be administered during a trial. In conclusion, flavored medications contain the common antigens soy, pork, and beef although they may or may not be listed on the ingredient list or product insert. PMID:25028437

  20. 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

  1. Applying propensity scores estimated in a full cohort to adjust for confounding in subgroup analyses

    PubMed Central

    Rassen, Jeremy A.; Glynn, Robert J.; Rothman, Kenneth J.; Setoguchi, Soko; Schneeweiss, Sebastian

    2012-01-01

    A correctly-specified propensity score (PS) estimated in a cohort (“cohort PS”) should in expectation remain valid in a subgroup population. We sought to determine whether using a cohort PS can be validly applied to subgroup analyses and thus add efficiency to studies with many subgroups or restricted data. In each of 3 cohort studies we estimated a cohort PS, defined 5 subgroups, and then estimated subgroup-specific PSs. We compared difference in treatment effect estimates for subgroup analyses adjusted by cohort PSs versus subgroup-specific PSs. Then, 10M times, we simulated a population with known characteristics of confounding, subgroup size, treatment interactions, and treatment effect, and again assessed difference in point estimates. We observed that point estimates in most subgroups were substantially similar with the two methods of adjustment. In simulations, the effect estimates differed by a median of 3.4% (interquartile [IQ] range 1.3% to 10.0%). The IQ range exceeded 10% only in cases where the subgroup had <1000 patients or few outcome events. Our empirical and simulation results indicated that using a cohort PS in subgroup analyses was a feasible approach, particularly in larger subgroups. PMID:22162077

  2. 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

  3. Stream solute tracer timescales changing with discharge and reach length confound process interpretation

    NASA Astrophysics Data System (ADS)

    Schmadel, Noah M.; Ward, Adam S.; Kurz, Marie J.; Fleckenstein, Jan H.; Zarnetske, Jay P.; Hannah, David M.; Blume, Theresa; Vieweg, Michael; Blaen, Phillip J.; Schmidt, Christian; Knapp, Julia L. A.; Klaar, Megan J.; Romeijn, Paul; Datry, Thibault; Keller, Toralf; Folegot, Silvia; Arricibita, Amaia I. Marruedo; Krause, Stefan

    2016-04-01

    Improved understanding of stream solute transport requires meaningful comparison of processes across a wide range of discharge conditions and spatial scales. At reach scales where solute tracer tests are commonly used to assess transport behavior, such comparison is still confounded due to the challenge of separating dispersive and transient storage processes from the influence of the advective timescale that varies with discharge and reach length. To better resolve interpretation of these processes from field-based tracer observations, we conducted recurrent conservative solute tracer tests along a 1 km study reach during a storm discharge period and further discretized the study reach into six segments of similar length but different channel morphologies. The resulting suite of data, spanning an order of magnitude in advective timescales, enabled us to (1) characterize relationships between tracer response and discharge in individual segments and (2) determine how combining the segments into longer reaches influences interpretation of dispersion and transient storage from tracer tests. We found that the advective timescale was the primary control on the shape of the observed tracer response. Most segments responded similarly to discharge, implying that the influence of morphologic heterogeneity was muted relative to advection. Comparison of tracer data across combined segments demonstrated that increased advective timescales could be misinterpreted as a change in dispersion or transient storage. Taken together, our results stress the importance of characterizing the influence of changing advective timescales on solute tracer responses before such reach-scale observations can be used to infer solute transport at larger network scales.

  4. 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

  5. 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

  6. 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…

  7. Climate change as a confounding factor in reversibility of acidification: RAIN and CLIMEX projects

    NASA Astrophysics Data System (ADS)

    Wright, R. F.; Jenkins, A.

    The RAIN and CLIMEX experiments at Risdalsheia, southernmost Norway, together cover 17 years (1984-2000) of whole-catchment manipulation of acid deposition and climate. A 1200 m2 roof placed over the forest canopy at KIM catchment excluded about 80% of ambient acid deposition; clean rain was sprinkled under the roof. A climate change treatment (3.7°C increase in air temperature and increase in air carbon dioxide concentrations to 560 ppmv) was superimposed on the clean rain treatment for four years (1995-1998). Sea-salt inputs and temperature are climate-related factors that influence water chemistry and can confound long-term trends caused by changes in deposition of sulphur and nitrogen. The RAIN and CLIMEX experiments at Risdalsheia provided direct experimental data that allow quantitative assessment of these factors. Run-off chemistry responded rapidly to the decreased acid deposition. Sulphate concentrations decreased by 50% within three years; nitrate and ammonium concentrations decreased to new steady-state levels within the first year. Acid neutralising capacity increased and hydrogen ion and inorganic aluminium decreased. Similar recovery from acidification was also observed at the reference catchment, ROLF, in response to the general 50% reduction in sulphate deposition over southern Norway in the late 1980s and 1990s. Variations in sea-salt deposition caused large variations in run-off chemistry at the reference catchment ROLF and the year-to-year noise in acid neutralising capacity was as large as the overall trend over the period. These variations were absent at KIM catchment because the sea-salt inputs were held constant over the entire 17 years of the clean rain treatment. The climate change experiment at KIM catchment resulted in increased leaching of inorganic nitrogen, probably due to increased mineralisation and nitrification rates in the soils.

  8. Incorporating linked healthcare claims to improve confounding control in a study of in-hospital medication use

    PubMed Central

    Franklin, Jessica M; Eddings, Wesley; Schneeweiss, Sebastian; Rassen, Jeremy A

    2015-01-01

    Introduction The Premier Perspective hospital billing database provides a promising data source for studies of inpatient medication use. However, in-hospital recording of confounders is limited, and incorporating linked healthcare claims data available for a subset of the cohort may improve confounding control. We investigated methods capable of adjusting for confounders measured in a subset, including complete case analysis, multiple imputation of missing data, and propensity score (PS) calibration. Methods Methods were implemented in an example study of adults in Premier undergoing percutaneous coronary intervention (PCI) in 2004-2008 and exposed to either bivalirudin or heparin. In a subset of patients enrolled in UnitedHealth for at least 90 days before hospitalization, additional confounders were assessed from healthcare claims, including comorbidities, prior medication use, and service use intensity. Diagnostics for each method were evaluated, and methods were compared with respect to the estimates and confidence intervals of treatment effects on repeat PCI, bleeding, and in-hospital death. Results Of 210,268 patients in the hospital-based cohort, 3,240 (1.5%) had linked healthcare claims. This subset was younger and healthier than the overall study population. The linked subset was too small for complete case evaluation of 2 of the 3 outcomes of interest. Multiple imputation and PS calibration did not meaningfully impact treatment effect estimates and associated confidence intervals. Conclusions Despite more than 98% missingness on 24 variables, PS calibration and multiple imputation incorporated confounders from healthcare claims without major increases in estimate uncertainty. Additional research is needed to determine the relative bias of these methods. PMID:25935198

  9. Levels and confounders of morning cortisol collected from adolescents in a naturalistic (school) setting.

    PubMed

    Kelly, Shona J; Young, Robert; Sweeting, Helen; Fischer, Joachim E; West, Patrick

    2008-10-01

    Salivary cortisol is widely used in research but little is known about the typical, or expected, functioning of the HPA-axis in adolescents in naturalistic settings, nor whether the extensive array of confounders documented in the literature is applicable in this situation. In a school-based study, 2995 15-year-old pupils provided two saliva samples, 30 min apart, in morning sessions timed to capture peak cortisol decline. The collection protocol was a balance between the large sample size obtainable in a school situation and a limited number of samples, constrained by the school timetable. In addition, pupils completed a questionnaire containing items previously shown to be associated with cortisol levels (e.g. time since awakening and life events), and their height and weight were measured. Outcome measures were cortisol levels at Times 1 and 2, and change (per minute) in cortisol between the two time points. Median (IQR) cortisol levels for males and females were 10.5 (8.1) and 11.6 (9.3) nmol/L at Time 1, and 8.2 (6.0) and 8.1 (6.5) nmol/L at Time 2. 73% had a decline in cortisol level of more than 10% across the two time points, compatible with the expected diurnal pattern. In bivariate analyses, cortisol sampled on Monday, times of measurement and since awakening, prior smoking and several life events were associated with cortisol levels at Times 1 and 2 in both sexes. However, in multivariate analysis, few of these variables remained after controlling for times of measurement and since awakening and, in addition, the final models differed between the sexes. Two events (friend dying and splitting with a boy/girlfriend) predicted cortisol levels in both sexes while age, maturity, recent eating and smoking were predictors only in males. Several factors associated with cortisol change differed from those observed for absolute levels. Further adjustment for school clustering affected some associations, particularly time of measurement. This study managed many of

  10. Highway proximity associated with cardiovascular disease risk: the influence of individual-level confounders and exposure misclassification

    PubMed Central

    2013-01-01

    Background Elevated cardiovascular disease risk has been reported with proximity to highways or busy roadways, but proximity measures can be challenging to interpret given potential confounders and exposure error. Methods We conducted a cross sectional analysis of plasma levels of C-Reactive Protein (hsCRP), Interleukin-6 (IL-6), Tumor Necrosis Factor alpha receptor II (TNF-RII) and fibrinogen with distance of residence to a highway in and around Boston, Massachusetts. Distance was assigned using ortho-photo corrected parcel matching, as well as less precise approaches such as simple parcel matching and geocoding addresses to street networks. We used a combined random and convenience sample of 260 adults >40 years old. We screened a large number of individual-level variables including some infrequently collected for assessment of highway proximity, and included a subset in our final regression models. We monitored ultrafine particle (UFP) levels in the study areas to help interpret proximity measures. Results Using the orthophoto corrected geocoding, in a fully adjusted model, hsCRP and IL-6 differed by distance category relative to urban background: 43% (-16%,141%) and 49% (6%,110%) increase for 0-50 m; 7% (-39%,45%) and 41% (6%,86%) for 50-150 m; 54% (-2%,142%) and 18% (-11%,57%) for 150-250 m, and 49% (-4%, 131%) and 42% (6%, 89%) for 250-450 m. There was little evidence for association for TNF-RII or fibrinogen. Ortho-photo corrected geocoding resulted in stronger associations than traditional methods which introduced differential misclassification. Restricted analysis found the effect of proximity on biomarkers was mostly downwind from the highway or upwind where there was considerable local street traffic, consistent with patterns of monitored UFP levels. Conclusion We found associations between highway proximity and both hsCRP and IL-6, with non-monotonic patterns explained partly by individual-level factors and differences between proximity and UFP

  11. Indoor biofuel air pollution and respiratory health: the role of confounding factors among women in highland Guatemala.

    PubMed

    Bruce, N; Neufeld, L; Boy, E; West, C

    1998-06-01

    The authors investigated the association between respiratory symptoms and the use of open fires and chimney woodstoves, as well as the distribution of confounding factors, in a cross-sectional study of 340 women aged 15-45 years living in a poor rural area in the western highlands of Guatemala, and found a significantly higher prevalence of reported cough and phlegm for 3 of 6 symptom measures among women using open fires. When considering confounding factors, very strong associations were found between the type of fire and a number of household and socioeconomic factors including the arrangement of rooms, floor type, and possession of a radio and television. The spouse's economic activity type was also significantly associated. 82% of open fire users had dirt floors, with the remaining 18% having cement or tile floors, while only 16% of chimney woodstove users had dirt floors. PMID:9698135

  12. Stratification-score matching improves correction for confounding by population stratification in case-control association studies.

    PubMed

    Epstein, Michael P; Duncan, Richard; Broadaway, K Alaine; He, Min; Allen, Andrew S; Satten, Glen A

    2012-04-01

    Proper control of confounding due to population stratification is crucial for valid analysis of case-control association studies. Fine matching of cases and controls based on genetic ancestry is an increasingly popular strategy to correct for such confounding, both in genome-wide association studies (GWASs) as well as studies that employ next-generation sequencing, where matching can be used when selecting a subset of participants from a GWAS for rare-variant analysis. Existing matching methods match on measures of genetic ancestry that combine multiple components of ancestry into a scalar quantity. However, we show that including nonconfounding ancestry components in a matching criterion can lead to inaccurate matches, and hence to an improper control of confounding. To resolve this issue, we propose a novel method that assigns cases and controls to matched strata based on the stratification score (Epstein et al. [2007] Am J Hum Genet 80:921-930), which is the probability of disease given genomic variables. Matching on the stratification score leads to more accurate matches because case participants are matched to control participants who have a similar risk of disease given ancestry information. We illustrate our matching method using the African-American arm of the GAIN GWAS of schizophrenia. In this study, we observe that confounding due to stratification can be resolved by our matching approach but not by other existing matching procedures. We also use simulated data to show our novel matching approach can provide a more appropriate correction for population stratification than existing matching approaches. PMID:22714934

  13. 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

  14. 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

  15. Holding Accountability to Account. Research Brief

    ERIC Educational Resources Information Center

    National Center on Performance Incentives, 2008

    2008-01-01

    In "Holding Accountability to Account: How Scholarship and Experience in Other Fields Inform Exploration of Performance Incentives in Education"--a paper presented at the National Center on Performance Incentives research to policy conference in February--Richard Rothstein, a research associate at the Economic Policy Institute, argues educational…

  16. Accountability, California Style: Counting or Accounting?

    ERIC Educational Resources Information Center

    Russell, Michael; Higgins, Jennifer; Raczek, Anastasia

    2004-01-01

    Across the nation and at nearly all levels of our educational system, efforts to hold schools accountable for student learning dominate strategies for improving the quality of education. At both the national and state level, student testing stands at the center of educational accountability programs, such that schools are effectively held…

  17. 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…

  18. Land surface controls on afternoon precipitation diagnosed from observational data: Uncertainties and confounding factors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The feedback between soil moisture and precipitation has long been a topic of interest due to its potential for improving weather and seasonal forecasts. The generally proposed mechanism assumes a control of soil moisture on precipitation via the partitioning of the surface fluxes (the Evaporative F...

  19. 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.

  20. 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.

  1. 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

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

    PubMed

    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

  3. Counselor Accountability Through Advisory Groups

    ERIC Educational Resources Information Center

    Johnson, Josephine; O'Brien, Charles R.

    1975-01-01

    Citizens' committees and advisory groups are one means of addressing the issue of accountability. This article suggests that such groups offer real potential to counselors for increasing their visibility, gaining substantive feedback and developing program improvement. Practical hints are included for the formation and operation of a Counseling…

  4. A principal stratification approach for evaluating natural direct and indirect effects in the presence of treatment-induced intermediate confounding.

    PubMed

    Taguri, Masataka; Chiba, Yasutaka

    2015-01-15

    Recently, several authors have shown that natural direct and indirect effects (NDEs and NIEs) can be identified under the sequential ignorability assumptions, as long as there is no mediator-outcome confounder that is affected by the treatment. However, if such a confounder exists, NDEs and NIEs will generally not be identified without making additional identifying assumptions. In this article, we propose novel identification assumptions and estimators for evaluating NDEs and NIEs under the usual sequential ignorability assumptions, using the principal stratification framework. It is assumed that the treatment and the mediator are dichotomous. We must impose strong assumptions for identification. However, even if these assumptions were violated, the bias of our estimator would be small under typical conditions, which can be easily evaluated from the observed data. This conjecture is confirmed for binary outcomes by deriving the bounds of the bias terms. In addition, the advantage of our estimator is illustrated through a simulation study. We also propose a method of sensitivity analysis that examines what happens when our assumptions are violated. We apply the proposed method to data from the National Center for Health Statistics. PMID:25312003

  5. Correlations between cannabis use and IQ change in the Dunedin cohort are consistent with confounding from socioeconomic status.

    PubMed

    Rogeberg, Ole

    2013-03-12

    Does cannabis use have substantial and permanent effects on neuropsychological functioning? Renewed and intense attention to the issue has followed recent research on the Dunedin cohort, which found a positive association between, on the one hand, adolescent-onset cannabis use and dependence and, on the other hand, a decline in IQ from childhood to adulthood [Meier et al. (2012) Proc Natl Acad Sci USA 109(40):E2657-E2664]. The association is given a causal interpretation by the authors, but existing research suggests an alternative confounding model based on time-varying effects of socioeconomic status on IQ. A simulation of the confounding model reproduces the reported associations from the Dunedin cohort, suggesting that the causal effects estimated in Meier et al. are likely to be overestimates, and that the true effect could be zero. Further analyses of the Dunedin cohort are proposed to distinguish between the competing interpretations. Although it would be too strong to say that the results have been discredited, the methodology is flawed and the causal inference drawn from the results premature. PMID:23319626

  6. Correlations between cannabis use and IQ change in the Dunedin cohort are consistent with confounding from socioeconomic status

    PubMed Central

    Rogeberg, Ole

    2013-01-01

    Does cannabis use have substantial and permanent effects on neuropsychological functioning? Renewed and intense attention to the issue has followed recent research on the Dunedin cohort, which found a positive association between, on the one hand, adolescent-onset cannabis use and dependence and, on the other hand, a decline in IQ from childhood to adulthood [Meier et al. (2012) Proc Natl Acad Sci USA 109(40):E2657–E2664]. The association is given a causal interpretation by the authors, but existing research suggests an alternative confounding model based on time-varying effects of socioeconomic status on IQ. A simulation of the confounding model reproduces the reported associations from the Dunedin cohort, suggesting that the causal effects estimated in Meier et al. are likely to be overestimates, and that the true effect could be zero. Further analyses of the Dunedin cohort are proposed to distinguish between the competing interpretations. Although it would be too strong to say that the results have been discredited, the methodology is flawed and the causal inference drawn from the results premature. PMID:23319626

  7. 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

  8. 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

  9. Accountability: A Mosaic Image

    ERIC Educational Resources Information Center

    Turner, Teri

    1977-01-01

    The problems involved in definition, implementation and control of accountability processes are discussed. It is stated that "...emotional involvement in accountability is one of the most difficult aspects to deal with, the chief emotion being fear". (Author/RW)

  10. 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.

  11. 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

  12. 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…

  13. 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…

  14. 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,…

  15. Intelligent Accountability in Education

    ERIC Educational Resources Information Center

    O'Neill, Onora

    2013-01-01

    Systems of accountability are "second order" ways of using evidence of the standard to which "first order" tasks are carried out for a great variety of purposes. However, more accountability is not always better, and processes of holding to account can impose high costs without securing substantial benefits. At their worst,…

  16. 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…

  17. Estimating controlled direct effects in the presence of intermediate confounding of the mediator-outcome relationship: Comparison of five different methods.

    PubMed

    Lepage, B; Dedieu, D; Savy, N; Lang, T

    2016-04-01

    In mediation analysis between an exposure X and an outcome Y, estimation of the direct effect of X on Y by usual regression after adjustment for the mediator M may be biased if Z is a confounder between M and Y, and is also affected by X Alternative methods have been described to avoid such a bias: inverse probability of treatment weighting with and without weight truncation, the sequential g-estimator and g-computation. Our aim was to compare the usual linear regression adjusted for M to these methods when estimating the controlled direct effect between X and Y in the causal structure and to explore the size of the potential bias. Estimations were computed in several simulated data sets as well as real data. We observed an increased bias of the controlled direct effect estimation using linear regression adjusted for M for larger effects of X on M and larger effects of Z on M The sequential g-estimator and g-computation gave unbiased estimations with adequate coverage values in every situation studied. With continuous exposure X and mediator M, inverse probability of treatment weighting resulted in some bias and less satisfactory coverage for large effects of X on M and Z on M. PMID:23070596

  18. Diffuse large B-cell lymphoma in colon confounded by prior history of colorectal cancer: A case report and literature review

    PubMed Central

    REN, YANLING; CHEN, ZHILU; SU, CHUANYONG; TONG, HONGYAN; QIAN, WENBIN

    2016-01-01

    A 66-year-old male underwent left hemicolectomy for rectal adenocarcinoma in 2008. Five years later he was admitted to hospital with abdominal pain. A computed tomography scan revealed notable thickening of the middle of the ascending colon wall, and colonoscopy revealed an ulcerofungating mass of 3×3 cm in the cecum and extending to the ascending colon. Under the consideration of cancer recurrence, laparoscopic right hemicolectomy was performed directly. Surgical specimens revealed sheets of large pleomorphic lymphoid cells with nuclei of different sizes, nucleoli and mitotic phases visible in most cells. These tested positive for CD45, CD20 and CD79a diffusely, but negative for CD3, CD5, Bcl-2, Bcl-6 and ALK. The Ki-67 proliferation index was 40%. Epstein-Barr virus in situ hybridization did not reveal any positive signals in any of the tumor cells. Based on these findings, the recurrent tumor was diagnosed as diffuse large B-cell lymphoma. The patient could have avoided surgery and received chemotherapy only; however, the case was confounded by the patient's prior history of colorectal cancer due to the rarity of colon lymphoma following rectal cancer in the same patient. It is therefore essential to investigate carefully and differentiate between potential lesions during routine postoperative colonoscopy following colorectal cancer surgery, as patients may present with rare colon lymphoma, which may be confused with a recurrence of colorectal cancer. PMID:26893766

  19. 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

  20. The confounded self-efficacy construct: conceptual analysis and recommendations for future research.

    PubMed

    Williams, David M; Rhodes, Ryan E

    2016-06-01

    Self-efficacy is central to health behaviour theories due to its robust predictive capabilities. In this paper, we present and review evidence for a self-efficacy-as-motivation argument in which standard self-efficacy questionnaires - i.e., ratings of whether participants 'can do' the target behaviour - reflect motivation rather than perceived capability. The potential implication is that associations between self-efficacy ratings (particularly those that employ a 'can do' operationalisation) and health-related behaviours simply indicate that people are likely to do what they are motivated to do. There is some empirical evidence for the self-efficacy-as-motivation argument, with three studies demonstrating causal effects of outcome expectancy on subsequent self-efficacy ratings. Three additional studies show that - consistent with the self-efficacy-as-motivation argument - controlling for motivation by adding the phrase 'if you wanted to' to the end of self-efficacy items decreases associations between self-efficacy ratings and motivation. Likewise, a qualitative study using a thought-listing procedure demonstrates that self-efficacy ratings have motivational antecedents. The available evidence suggests that the self-efficacy-as-motivation argument is viable, although more research is needed. Meanwhile, we recommend that researchers look beyond self-efficacy to identify the many and diverse sources of motivation for health-related behaviours. PMID:25117692

  1. Mutant DNA quantification by digital PCR can be confounded by heating during DNA fragmentation.

    PubMed

    Kang, Qing; Parkin, Brian; Giraldez, Maria D; Tewari, Muneesh

    2016-04-01

    Digital PCR (dPCR) is gaining popularity as a DNA mutation quantification method for clinical specimens. Fragmentation prior to dPCR is required for non-fragmented genomic DNA samples; however, the effect of fragmentation on DNA analysis has not been well-studied. Here we evaluated three fragmentation methods for their effects on dPCR point mutation assay performance. Wild-type (WT) human genomic DNA was fragmented by heating, restriction digestion, or acoustic shearing using a Covaris focused-ultrasonicator. dPCR was then used to determine the limit of blank (LoB) by quantifying observed WT and mutant allele counts of the proto-oncogenes KRAS and BRAF in the WT DNA sample. DNA fragmentation by heating to 95°C, while the simplest and least expensive method, produced a high background mutation frequency for certain KRAS mutations relative to the other methods. This was due to heat-induced mutations, specifically affecting dPCR assays designed to interrogate guanine to adenine (G>A) mutations. Moreover, heat-induced fragmentation overestimated gene copy number, potentially due to denaturation and partition of single-stranded DNA into different droplets. Covaris acoustic shearing and restriction enzyme digestion showed similar LoBs and gene copy number estimates to one another. It should be noted that moderate heating, commonly used in genomic DNA extraction protocols, did not significantly increase observed KRAS mutation counts. PMID:27071606

  2. 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

  3. Loss of mitochondrial transmembrane potential and glutathione depletion are not sufficient to account for induction of apoptosis by carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone in human leukemia K562 cells.

    PubMed

    Mlejnek, Petr; Dolezel, Petr

    2015-09-01

    Carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone (FCCP), an uncoupler of mitochondrial oxidative phosphorylation, inhibits cell proliferation and induces cell death with apoptotic features. It was reported that the cytotoxic effects of FCCP are preceded by a rapid glutathione (GSH) depletion with a subsequent loss of mitochondrial transmembrane potential (ΔΨ). The GSH depletion was suggested as the cause of apoptosis in FCCP treated cells. This conclusion was further supported by the finding that all adverse effects of FCCP including cell death can be prevented by N-acetylcysteine (NAC) a precursor of GSH synthesis (Han and Park, 2011). Here, we argue that neither loss of ΔΨ nor GSH depletion is sufficient to account for induction of apoptosis in FCCP treated leukemia K562 cells. Indeed, the lowest concentration of FCCP that brings about the permanent loss of ΔΨ and the extensive decrease in GSH level induces cell death in minor population of cells. Only much higher concentrations of FCCP, that exceed the range to achieve permanent collapse of ΔΨ, induce extensive apoptosis. The low proapoptotic activity of FCCP could be explained by hyperactivation of protein kinase B/Akt. A detailed LC/MS/MS analysis of cell extracts revealed extensive formation of FCCP adducts with GSH. This effect could explain the mechanism of GSH depletion, which is currently unknown. Although NAC induces an increase in the GSH pool, this effect is not crucial for abrogation of FCCP cytotoxicity. Indeed, the presence of NAC in the growth medium causes a rapid clearance of FCCP due to its quantitative conversion into the FCCP-NAC adduct, which is the real cause of abrogated FCCP cytotoxicity. PMID:26115783

  4. 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

  5. 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

  6. Neuroticism explains unwanted variance in Implicit Association Tests of personality: possible evidence for an affective valence confound

    PubMed Central

    Fleischhauer, Monika; Enge, Sören; Miller, Robert; Strobel, Alexander; Strobel, Anja

    2013-01-01

    Meta-analytic data highlight the value of the Implicit Association Test (IAT) as an indirect measure of personality. Based on evidence suggesting that confounding factors such as cognitive abilities contribute to the IAT effect, this study provides a first investigation of whether basic personality traits explain unwanted variance in the IAT. In a gender-balanced sample of 204 volunteers, the Big-Five dimensions were assessed via self-report, peer-report, and IAT. By means of structural equation modeling (SEM), latent Big-Five personality factors (based on self- and peer-report) were estimated and their predictive value for unwanted variance in the IAT was examined. In a first analysis, unwanted variance was defined in the sense of method-specific variance which may result from differences in task demands between the two IAT block conditions and which can be mirrored by the absolute size of the IAT effects. In a second analysis, unwanted variance was examined in a broader sense defined as those systematic variance components in the raw IAT scores that are not explained by the latent implicit personality factors. In contrast to the absolute IAT scores, this also considers biases associated with the direction of IAT effects (i.e., whether they are positive or negative in sign), biases that might result, for example, from the IAT's stimulus or category features. None of the explicit Big-Five factors was predictive for method-specific variance in the IATs (first analysis). However, when considering unwanted variance that goes beyond pure method-specific variance (second analysis), a substantial effect of neuroticism occurred that may have been driven by the affective valence of IAT attribute categories and the facilitated processing of negative stimuli, typically associated with neuroticism. The findings thus point to the necessity of using attribute category labels and stimuli of similar affective valence in personality IATs to avoid confounding due to recoding. PMID

  7. 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.…

  8. Computerizing the Accounting Curriculum.

    ERIC Educational Resources Information Center

    Nash, John F.; England, Thomas G.

    1986-01-01

    Discusses the use of computers in college accounting courses. Argues that the success of new efforts in using computers in teaching accounting is dependent upon increasing instructors' computer skills, and choosing appropriate hardware and software, including commercially available business software packages. (TW)

  9. 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…

  10. The Choreography of Accountability

    ERIC Educational Resources Information Center

    Webb, P. Taylor

    2006-01-01

    The prevailing performance discourse in education claims school improvements can be achieved through transparent accountability procedures. The article identifies how teachers generate performances of their work in order to satisfy accountability demands. By identifying sources of teachers' knowledge that produce choreographed performances, I…

  11. 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…

  12. 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…

  13. 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…

  14. The Accountability Illusion: Georgia

    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…

  15. The Accountability Controversy

    ERIC Educational Resources Information Center

    Glisson, Charles

    1975-01-01

    Author discusses accountability controversy concerning effectiveness of social services. Turem's mechanistic and Gruber's organic models of accountability are compared and an alternate open system model of organization is offered which combines positive aspects of Turem's and Gruber's models as well as adds other constructive elements to them. (SE)

  16. The Accountability Illusion: Kansas

    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…

  17. 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…

  18. The Accountability Illusion: Texas

    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…

  19. Responsible and accountable.

    PubMed

    Woodrow, Philip

    2006-03-01

    Healthcare assistants are valuable members of the multi-disciplinary team, using many skills outlined in previous articles in this series. But anyone exceeding the limits of their skills can cause harm and may be called to account. This article explains how everyone is accountable. PMID:16538993

  20. 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…

  1. 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

  2. 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

  3. 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. PMID:27260827

  4. 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…

  5. 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

  6. 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

  7. Human Resource Accounting System

    ERIC Educational Resources Information Center

    Cerullo, Michael J.

    1974-01-01

    Main objectives of human resource accounting systems are to satisfy the informational demands made by investors and by operating managers. The paper's main concern is with the internal uses of a human asset system. (Author)

  8. Cannabinoid receptor activation in the juvenile rat brain results in rapid biomechanical alterations: Neurovascular mechanism as a putative confounding factor.

    PubMed

    Chatelin, Simon; Humbert-Claude, Marie; Garteiser, Philippe; Ricobaraza, Ana; Vilgrain, Valérie; Van Beers, Bernard E; Sinkus, Ralph; Lenkei, Zsolt

    2016-05-01

    We have recently reported cannabinoid-induced rapid changes in the structure of individual neurons. In order to investigate the presence of similar effects at the regional level, measures of brain tissue biomechanics are required. However, cannabinoids are known to alter cerebral blood flow (CBF), putatively resulting in presently unexplored changes in cerebral tissue biomechanics. Here we used magnetic resonance elastography (MRE) and flow-sensitive alternating inversion recovery (FAIR) imaging to measure in vivo alterations of mechanical properties and CBF, respectively, in the rat hippocampus, a brain region with a high density of type-1 cannabinoid receptors (CB1R). Systemic injection of the cannabinoid agonist CP55,940 (0.7 mg/kg) induced a significant stiffness decrease of 10.5 ± 1.2% at 15 minutes. FAIR imaging indicated a comparable decrease (11.3 ± 1.9%) in CBF. Both effects were specific to CB1R activation, as shown by pretreatment with the CB1R-specific antagonist AM251. Strikingly, similar rapid parallel changes of brain elasticity and CBF were also observed after systemic treatment with the hypotensive drug nicardipine. Our results reveal important drug-induced parallel changes in CBF and brain mechanical characteristics, and show that blood flow-dependent tissue softening has to be considered as an important putative confounding factor when cerebral viscoelastic changes are investigated. PMID:26661178

  9. 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

  10. Zooplankton community changes confound the biodilution theory of methylmercury accumulation in a recovering mercury-contaminated lake.

    PubMed

    Todorova, Svetoslava; Driscoll, Charles T; Matthews, David A; Effler, Steven W

    2015-04-01

    In this study, the biodilution hypothesis of methylmercury (MeHg) accumulation was examined in a Hg-contaminated ecosystem that has undergone concurrent changes in nutrient loading and zooplankton community composition. Using a long-term record of 17 years (between 1980 and 2009), we demonstrate that zooplankton MeHg concentrations in Onondaga Lake, NY, are strongly driven by changes in the zooplankton community and body size. MeHg concentrations in zooplankton increased with an increase in body size and biomass. The highest concentrations of MeHg were observed under eutrophic and hypereutrophic conditions when large-bodied Daphnia species, Daphnia pulicaria and Daphnia galeata mendotae, were present. Bioconcentration rather than biodilution was governing the accumulation of MeHg in zooplankton without apparent growth dilution or zooplankton biomass dilution. Algal-bloom dilution controlled the variability in the MeHg concentration only under hypereutrophic conditions when Ceriodaphnia predominated the cladoceran population. Our study demonstrates that changes in zooplankton community composition confound the biodilution theory in Onondaga Lake and that the presence of large-bodied zooplankton species drives elevated MeHg concentrations. PMID:25741879

  11. The confounding effects of light, sonication, and Mn(III)TBAP on quantitation of superoxide using hydroethidine.

    PubMed

    Zielonka, Jacek; Vasquez-Vivar, Jeannette; Kalyanaraman, B

    2006-10-01

    Previously, we showed that hydroethidine (HE) reacts with intracellular superoxide radical anion (O2-*) to form a unique fluorescent marker product, 2-hydroxyethidium cation (2-OH-E+), that was not formed from HE reaction with other biologically relevant oxidants (H. Zhao et al. Proc. Natl. Acad. Sci. USA102:5727-5732; 2005). Here we rigorously assessed the confounding effects of light, sonication, and Mn(III)TBAP on 2-OH-E+, the HE/O2-* reaction product. Results indicate that continuous exposure to visible light induced photo-oxidation of HE to ethidium cation (E+) by a 2-OH-E+ -dependent mechanism. Treatment of HE with ultrasound, a frequently used technique to lyse cell membranes, induced 2-OH-E+ from in situ generation of O2-*. Mn(III)TBAP, a cell-permeable metal-porphyrin complex used as a catalytic antioxidant, reacts with HE to form E+. This finding provides an alternative interpretation for Mn(III)TBAP effects during the HE/O2-* reaction. In order to correctly interpret the HE reaction with O2-* in cells, it is therefore imperative that HE and HE-derived products be measured by HPLC. A new and improved HPLC-electrochemical (HPLC-EC) detection has been developed for analysis of intracellular O2-*. The HPLC-EC method is at least 10 times more sensitive than the HPLC-fluorescence technique for detecting O2-* in cells. PMID:16962930

  12. 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…

  13. 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

  14. 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

  15. Do time-invariant confounders explain away the association between job stress and workers' mental health? Evidence from Japanese occupational panel data.

    PubMed

    Oshio, Takashi; Tsutsumi, Akizumi; Inoue, Akiomi

    2015-02-01

    It is well known that job stress is negatively related to workers' mental health, but most recent studies have not controlled for unobserved time-invariant confounders. In the current study, we attempted to validate previous observations on the association between job stress and workers' mental health, by removing the effects of unobserved time-invariant confounders. We used data from three to four waves of an occupational Japanese cohort survey, focusing on 31,382 observations of 9741 individuals who participated in at least two consecutive waves. We estimated mean-centered fixed effects models to explain psychological distress in terms of the Kessler 6 (K6) scores (range: 0-24) by eight job stress indicators related to the job demands-control, effort-reward imbalance, and organizational injustice models. Mean-centered fixed effects models reduced the magnitude of the association between jobs stress and K6 scores to 44.8-54.2% of those observed from pooled ordinary least squares. However, the association remained highly significant even after controlling for unobserved time-invariant confounders for all job stress indicators. In addition, alternatively specified models showed the robustness of the results. In all, we concluded that the validity of major job stress models, which link job stress and workers' mental health, was robust, although unobserved time-invariant confounders led to an overestimation of the association. PMID:25550077

  16. Are apparent negative effects of feeding GM MON810 maize to Atlantic salmon, Salmo salar, caused by confounding factors?

    PubMed

    Sissener, Nini H; Hemre, Gro-Ingunn; Lall, Santosh P; Sagstad, Anita; Petersen, Kjell; Williams, Jason; Rohloff, Jens; Sanden, Monica

    2011-07-01

    The present study was conducted to follow up on apparent differences in growth, relative organ sizes, cellular stress and immune function in Atlantic salmon fed feed containing GM Bacillus thuringiensis maize compared with feed containing the non-modified parental maize line. Gene expression profiling on the distal intestinal segment and liver was performed by microarray, and selected genes were followed up by quantitative PCR (qPCR). In the liver, qPCR revealed some differentially regulated genes, including up-regulation of gelsolin precursor, down-regulation of ferritin heavy subunit and a tendency towards down-regulation of metallothionein (MT)-B. This, combined with the up-regulation of anti-apoptotic protein NR13 and similar tendencies for ferritin heavy chain and MT-A and -B in the distal intestine, suggests changes in cellular stress/antioxidant status. This corresponds well with and strengthens previous findings in these fish. To exclude possible confounding factors, the maize ingredients were analysed for mycotoxins and metabolites. The GM maize contained 90 μg/kg of deoxynivalenol (DON), while the non-GM maize was below the detection limit. Differences were also observed in the metabolite profiles of the two maize varieties, some of which seemed connected to the mycotoxin level. The effects on salmon observed in the present and previous studies correspond relatively well with the effects of DON as reported in the literature for other production animals, but knowledge regarding effects and harmful dose levels in fish is scarce. Thus, it is difficult to conclude whether the observed effects are caused by the DON level or by some other aspect of the GM maize ingredient. PMID:21418706

  17. 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

  18. 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.

  19. 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...

  20. 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... GAS ACT Operation and Maintenance Expense Chart of Accounts § 367.9040 Account 904, Uncollectible accounts. This account must be charged with amounts sufficient to provide for losses from...

  1. 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…

  2. 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…

  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. Accountability Measures Report, 2007

    ERIC Educational Resources Information Center

    North Dakota University System, 2007

    2007-01-01

    This document is a tool for demonstrating that the University System is meeting the "flexibility with accountability" expectations of SB 2003 passed by the 2001 Legislative Assembly. The 2007 report reflects some of the many ways North Dakota University System (NDUS) colleges and universities are developing the human capital needed to create a…

  5. Accountability Measures Report, 2006

    ERIC Educational Resources Information Center

    North Dakota University System, 2006

    2006-01-01

    This document is a valuable tool for demonstrating that the University System is meeting the "flexibility with accountability" expectations of SB 2003 passed by the 2001 Legislative Assembly. The 2006 report reflects some of the many ways North Dakota University System (NDUS) colleges and universities are developing the human capital needed to…

  6. Accounting Forms. Instructor's Handbook.

    ERIC Educational Resources Information Center

    Itter, Pat

    Supporting performance objective of the 16 V-TECS (Vocational-Technical Education Consortium of States) Bookkeeper Catalog, this instructor's manual contains copies of accounting forms which can be used to make spirit masters or transparencies. (This module is the first in a set of ten on bookkeeping [CE 019 480-489].) Twenty forms grouped under…

  7. Viewpoints on Accountability.

    ERIC Educational Resources Information Center

    Educational Innovators Press, Tucson, AZ.

    This booklet contains five papers which examine the activities, successes, and pitfalls encountered by educators who are introducing accountability techniques into instructional programs where they did not exist in the past. The papers are based on actual programs and offer possible solutions in the areas considered, which are 1) performance…

  8. 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…

  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. 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…

  11. 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…

  12. 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.

  13. 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…

  14. 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…

  15. Assessment and Accountability.

    ERIC Educational Resources Information Center

    Au, Kathryn

    2001-01-01

    Discusses six books that give a range of perspectives on the issues of assessment and accountability, from the use of standardized reading tests to creating student and professional portfolios. States that these books will provide teachers with the knowledge to make sound assessment decisions and with practical suggestions to document student and…

  16. 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…

  17. Accountability in Action.

    ERIC Educational Resources Information Center

    Dumke, Glenn S.

    Since education has become big business, the reactions of the academic community to social change are of immense political and social effect. Therefore, before higher education can deal with the question of accountability, it has to define the role of the college or university in relation to society. One alternative is that the campus operate as…

  18. 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…

  19. Measurements and material accounting

    SciTech Connect

    Hammond, G.A. )

    1989-11-01

    The DOE role for the NBL in safeguarding nuclear material into the 21st century is discussed. Development of measurement technology and reference materials supporting requirements of SDI, SIS, AVLIS, pyrochemical reprocessing, fusion, waste storage, plant modernization program, and improved tritium accounting are some of the suggested examples.

  20. 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…

  1. 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…

  2. 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. PMID:20583648

  3. 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.

  4. 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

  5. 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…

  6. 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…

  7. 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…

  8. Evaluation of accountability measurements

    SciTech Connect

    Cacic, C.G.

    1988-01-01

    The New Brunswick Laboratory (NBL) is programmatically responsible to the U.S. Department of Energy (DOE) Office of Safeguards and Security (OSS) for providing independent review and evaluation of accountability measurement technology in DOE nuclear facilities. This function is addressed in part through the NBL Safegaurds Measurement Evaluation (SME) Program. The SME Program utilizes both on-site review of measurement methods along with material-specific measurement evaluation studies to provide information concerning the adequacy of subject accountability measurements. This paper reviews SME Program activities for the 1986-87 time period, with emphasis on noted improvements in measurement capabilities. Continued evolution of the SME Program to respond to changing safeguards concerns is discussed.

  9. 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

  10. 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…

  11. 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

  12. 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

  13. 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.

  14. 18 CFR 367.1840 - Account 184, Clearing accounts.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 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... ACT Balance Sheet Chart of Accounts Deferred Debits § 367.1840 Account 184, Clearing accounts....

  15. 18 CFR 367.1840 - Account 184, Clearing accounts.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 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... ACT Balance Sheet Chart of Accounts Deferred Debits § 367.1840 Account 184, Clearing accounts....

  16. 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... ACT Balance Sheet Chart of Accounts Deferred Debits § 367.1840 Account 184, Clearing accounts....

  17. 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... ACT Balance Sheet Chart of Accounts Deferred Debits § 367.1840 Account 184, Clearing accounts....

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

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 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... ACT Balance Sheet Chart of Accounts Deferred Debits § 367.1840 Account 184, Clearing accounts....

  19. 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,…

  20. 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…

  1. 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. PMID:19064476

  2. 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.

  3. 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

  4. Performance testing accountability measurements

    SciTech Connect

    Oldham, R.D.; Mitchell, W.G.; Spaletto, M.I.

    1993-12-31

    The New Brunswick Laboratory (NBL) provides assessment support to the DOE Operations Offices in the area of Material Control and Accountability (MC and A). During surveys of facilities, the Operations Offices have begun to request from NBL either assistance in providing materials for performance testing of accountability measurements or both materials and personnel to do performance testing. To meet these needs, NBL has developed measurement and measurement control performance test procedures and materials. The present NBL repertoire of performance tests include the following: (1) mass measurement performance testing procedures using calibrated and traceable test weights, (2) uranium elemental concentration (assay) measurement performance tests which use ampulated solutions of normal uranyl nitrate containing approximately 7 milligrams of uranium per gram of solution, and (3) uranium isotopic measurement performance tests which use ampulated uranyl nitrate solutions with enrichments ranging from 4% to 90% U-235. The preparation, characterization, and packaging of the uranium isotopic and assay performance test materials were done in cooperation with the NBL Safeguards Measurements Evaluation Program since these materials can be used for both purposes.

  5. 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…

  6. 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…

  7. Program Accounting for Indiana Schools.

    ERIC Educational Resources Information Center

    Copeland, Jack; Costerison, Dennis

    This booklet outlines the conversion of the Western Wayne (Indiana) Schools from a traditional school accounting and budgeting system to a program accounting and budgeting system. The Western Wayne Schools became the first district to adopt Indiana's new program accounting and budgeting system in 1975. The Indiana approach to program accounting is…

  8. 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)

  9. 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. PMID:17411806

  10. 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.

  11. 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.

  12. 18 CFR 367.1420 - Account 142, Customer accounts receivable.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... merchandising, jobbing and contract work. This account must not include amounts due from associate companies. (b) This account must be maintained so as to permit ready segregation of the amounts due for...

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

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... merchandising, jobbing and contract work. This account must not include amounts due from associate companies. (b) This account must be maintained so as to permit ready segregation of the amounts due for...

  14. Accounting for smoking in the radon-related lung cancer risk among German uranium miners: results of a nested case-control study.

    PubMed

    Schnelzer, Maria; Hammer, Gaël P; Kreuzer, Michaela; Tschense, Annemarie; Grosche, Bernd

    2010-01-01

    The possible confounding effect of smoking on radon-associated risk for lung cancer mortality was investigated in a case-control study nested in the cohort of German uranium miners. The study included 704 miners who died of lung cancer and 1,398 controls matched individually for birth year and attained age. Smoking status was reconstructed from questionnaires and records from the mining company's health archives for 421 cases and 620 controls. Data on radon exposure were taken from a job-exposure matrix. Smoking adjusted odds ratios for lung cancer in relation to cumulative radon exposure have been calculated with conditional logistic regression. The increase in risk per Working Level Month (WLM) was assessed with a linear excess relative risk (ERR) model taking smoking into account as a multiplicative factor. In addition, the potential impact of temporal factors on the ERR per WLM was examined. Lung cancer mortality risk increased with increasing radon exposure, yielding a crude ERR per WLM of 0.25% (95% CI: 0.13-0.46%). Adjustment for smoking led only to marginal changes of the radon-associated lung cancer risks. The adjusted ERR per WLM was very similar (0.23%, 95%-CI: 0.11-0.46%) to the crude risk and to the risk found in the Wismut cohort study. This stability of the radon-related lung cancer risks with and without adjustment for smoking suggests that smoking does not act as a major confounder in this study and presumably also not in the cohort study. PMID:19959947

  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. 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...

  17. 18 CFR 367.1430 - Account 143, Other accounts receivable.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... accounts receivable. 367.1430 Section 367.1430 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY REGULATIONS UNDER THE PUBLIC UTILITY HOLDING COMPANY ACT OF 2005... GAS ACT Balance Sheet Chart of Accounts Current and Accrued Assets § 367.1430 Account 143,...

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

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... accounts receivable. 367.1430 Section 367.1430 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY REGULATIONS UNDER THE PUBLIC UTILITY HOLDING COMPANY ACT OF 2005... GAS ACT Balance Sheet Chart of Accounts Current and Accrued Assets § 367.1430 Account 143,...

  19. 18 CFR 367.1430 - Account 143, Other accounts receivable.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... accounts receivable. 367.1430 Section 367.1430 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY REGULATIONS UNDER THE PUBLIC UTILITY HOLDING COMPANY ACT OF 2005... GAS ACT Balance Sheet Chart of Accounts Current and Accrued Assets § 367.1430 Account 143,...

  20. 18 CFR 367.1430 - Account 143, Other accounts receivable.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... accounts receivable. 367.1430 Section 367.1430 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY REGULATIONS UNDER THE PUBLIC UTILITY HOLDING COMPANY ACT OF 2005... GAS ACT Balance Sheet Chart of Accounts Current and Accrued Assets § 367.1430 Account 143,...

  1. 18 CFR 367.1420 - Account 142, Customer accounts receivable.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... accounts receivable. 367.1420 Section 367.1420 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY REGULATIONS UNDER THE PUBLIC UTILITY HOLDING COMPANY ACT OF 2005... GAS ACT Balance Sheet Chart of Accounts Current and Accrued Assets § 367.1420 Account 142,...

  2. 18 CFR 367.1420 - Account 142, Customer accounts receivable.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... accounts receivable. 367.1420 Section 367.1420 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY REGULATIONS UNDER THE PUBLIC UTILITY HOLDING COMPANY ACT OF 2005... GAS ACT Balance Sheet Chart of Accounts Current and Accrued Assets § 367.1420 Account 142,...

  3. 18 CFR 367.1430 - Account 143, Other accounts receivable.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... accounts receivable. 367.1430 Section 367.1430 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY REGULATIONS UNDER THE PUBLIC UTILITY HOLDING COMPANY ACT OF 2005... GAS ACT Balance Sheet Chart of Accounts Current and Accrued Assets § 367.1430 Account 143,...

  4. 18 CFR 367.1420 - Account 142, Customer accounts receivable.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... accounts receivable. 367.1420 Section 367.1420 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY REGULATIONS UNDER THE PUBLIC UTILITY HOLDING COMPANY ACT OF 2005... GAS ACT Balance Sheet Chart of Accounts Current and Accrued Assets § 367.1420 Account 142,...

  5. 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)

  6. 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…

  7. 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…

  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. 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.

  10. 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.

  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. Experimental Subarachnoid Hemorrhage in Rats: Comparison of Two Endovascular Perforation Techniques with Respect to Success Rate, Confounding Pathologies and Early Hippocampal Tissue Lesion Pattern

    PubMed Central

    Höllig, Anke; Weinandy, Agnieszka; Nolte, Kay; Clusmann, Hans; Rossaint, Rolf; Coburn, Mark

    2015-01-01

    Recently aside from the “classic” endovascular monofilament perforation technique to induce experimental subarachnoid hemorrhage (SAH) a modification using a tungsten wire advanced through a guide tube has been described. We aim to assess both techniques for their success rate (induction of SAH without confounding pathologies) as primary endpoint. Further, the early tissue lesion pattern as evidence for early brain injury will be analyzed as secondary endpoint. Sprague Dawley rats (n=39) were randomly assigned to receive either Sham surgery (n=4), SAH using the “classic” technique (n=18) or using a modified technique (n=17). Course of intracranial pressure (ICP) and regional cerebral blood flow (rCBF) was analyzed; subsequent pathologies were documented either 6 or 24 h after SAH. Hippocampal tissue samples were analyzed via immunohistochemistry and western blotting. SAH-induction, regardless of confounding pathologies, was independent from type of technique (p=0.679). There was no significant difference concerning case fatality rate (classic: 40%; modified: 20%; p=0.213). Successful induction of SAH without collateral ICH or SDH was possible in 40% with the classic and in 86.7% with the modified technique (p=0.008). Peak ICP levels differed significantly between the two groups (classic: 94 +/- 23 mmHg; modified: 68 +/- 19 mmHg; p=0.003). Evidence of early cellular stress response and activation of apoptotic pathways 6 h after SAH was demonstrated. The extent of stress response is not dependent on type of technique. Both tested techniques successfully produce SAH including activation of an early stress response and apoptotic pathways in the hippocampal tissue. However, the induction of SAH with less confounding pathologies was more frequently achieved with the modified tungsten wire technique. PMID:25867893

  13. 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.

  14. '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

  15. Accounting Systems for School Districts.

    ERIC Educational Resources Information Center

    Atwood, E. Barrett, Jr.

    1983-01-01

    Advises careful analysis and improvement of existing school district accounting systems prior to investment in new ones. Emphasizes the importance of attracting and maintaining quality financial staffs, developing an accounting policies and procedures manual, and designing a good core accounting system before purchasing computer hardware and…

  16. Model Accounting Program. Adopters Guide.

    ERIC Educational Resources Information Center

    Beaverton School District 48, OR.

    The accounting cluster demonstration project conducted at Aloha High School in the Beaverton, Oregon, school district developed a model curriculum for high school accounting. The curriculum is based on interviews with professionals in the accounting field and emphasizes the use of computers. It is suitable for use with special needs students as…

  17. 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…

  18. 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…

  19. 46 CFR Sec. 5 - Accounting.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 8 2011-10-01 2011-10-01 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....

  20. 46 CFR Sec. 5 - Accounting.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 8 2012-10-01 2012-10-01 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....

  1. 46 CFR Sec. 5 - Accounting.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 8 2014-10-01 2014-10-01 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....

  2. 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....

  3. 46 CFR Sec. 5 - Accounting.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 8 2013-10-01 2013-10-01 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....

  4. 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…

  5. 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…

  6. 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

  7. 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. PMID:27037630

  8. Gene therapy restores vision in rd1 mice after removal of a confounding mutation in Gpr179.

    PubMed

    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

  9. 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...

  10. 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...

  11. Moral accountability and debriefing.

    PubMed

    Benham, Bryan

    2008-09-01

    What is the ethical significance of debriefing in deceptive research? The standard view of debriefing is that it serves to disclose the deception to the participant and is a means of evaluating and mitigating potential harms that may have resulted from involvement in the research. However, as the article by Miller, Gluck, and Wendler in this issue of the Kennedy Institute of Ethics Journal points out, there has been little systematic attention to the ethics of debriefing, particularly with regard to the role of debriefing in addressing the prima facie moral wrong of deception itself. They argue that in addition to mitigating the harms of deception, debriefing should include an apology to participants for being deceived. In the current paper, I argue that an apology is not morally obligatory in most research contexts. Debriefing should be considered an opportunity to further define the researcher-participant relationship without the need to be remorseful about the research practice. PMID:18935923

  12. 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

  13. 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

  14. Improving CSF Biomarkers’ Performance for Predicting Progression from Mild Cognitive Impairment to Alzheimer’s Disease by Considering Different Confounding Factors: A Meta-Analysis

    PubMed Central

    Ferreira, Daniel; Rivero-Santana, Amado; Perestelo-Pérez, Lilisbeth; Westman, Eric; Wahlund, Lars-Olof; Sarría, Antonio; Serrano-Aguilar, Pedro

    2014-01-01

    Background: Cerebrospinal fluid (CSF) biomarkers’ performance for predicting conversion from mild cognitive impairment (MCI) to Alzheimer’s disease (AD) is still suboptimal. Objective: By considering several confounding factors we aimed to identify in which situations these CSF biomarkers can be useful. Data Sources: A systematic review was conducted on MEDLINE, PreMedline, EMBASE, PsycInfo, CINAHL, Cochrane, and CRD (1990–2013). Eligibility Criteria: (1) Prospective studies of CSF biomarkers’ performance for predicting conversion from MCI to AD/dementia; (2) inclusion of Aβ42 and T-tau and/or p-tau. Several meta-analyses were performed. Results: Aβ42/p-tau ratio had high capacity to predict conversion to AD in MCI patients younger than 70 years. The p-tau had high capacity to identify MCI cases converting to AD in ≤24 months. Conclusions: Explaining how different confounding factors influence CSF biomarkers’ predictive performance is mandatory to elaborate a definitive map of situations, where these CSF biomarkers are useful both in clinics and research. PMID:25360114

  15. 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

  16. Phosphotyrosine signaling analysis in human tumors is confounded by systemic ischemia-driven artifacts and intra-specimen heterogeneity.

    PubMed

    Gajadhar, Aaron S; Johnson, Hannah; Slebos, Robbert J C; Shaddox, Kent; Wiles, Kerry; Washington, Mary Kay; Herline, Alan J; Levine, Douglas A; Liebler, Daniel C; White, Forest M

    2015-04-01

    Tumor protein phosphorylation analysis may provide insight into intracellular signaling networks underlying tumor behavior, revealing diagnostic, prognostic or therapeutic information. Human tumors collected by The Cancer Genome Atlas program potentially offer the opportunity to characterize activated networks driving tumor progression, in parallel with the genetic and transcriptional landscape already documented for these tumors. However, a critical question is whether cellular signaling networks can be reliably analyzed in surgical specimens, where freezing delays and spatial sampling disparities may potentially obscure physiologic signaling. To quantify the extent of these effects, we analyzed the stability of phosphotyrosine (pTyr) sites in ovarian and colon tumors collected under conditions of controlled ischemia and in the context of defined intratumoral sampling. Cold-ischemia produced a rapid, unpredictable, and widespread impact on tumor pTyr networks within 5 minutes of resection, altering up to 50% of pTyr sites by more than 2-fold. Effects on adhesion and migration, inflammatory response, proliferation, and stress response pathways were recapitulated in both ovarian and colon tumors. In addition, sampling of spatially distinct colon tumor biopsies revealed pTyr differences as dramatic as those associated with ischemic times, despite uniform protein expression profiles. Moreover, intratumoral spatial heterogeneity and pTyr dynamic response to ischemia varied dramatically between tumors collected from different patients. Overall, these findings reveal unforeseen phosphorylation complexity, thereby increasing the difficulty of extracting physiologically relevant pTyr signaling networks from archived tissue specimens. In light of this data, prospective tumor pTyr analysis will require appropriate sampling and collection protocols to preserve in vivo signaling features. PMID:25670172

  17. 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

  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. PMID:22834741

  19. Ex Vivo Restimulation of Human PBMC Expands a CD3+CD4−CD8−γδ+ T Cell Population That Can Confound the Evaluation of CD4 and CD8 T Cell Responses to Vaccination

    PubMed Central

    Sedgmen, B. J.; Papalia, L.; Wang, L.; Dyson, A. R.; McCallum, H. A.; Simson, C. M.; Pearse, M. J.; Maraskovsky, E.; Hung, D.; Eomois, P. P.; Hartel, G.; Barnden, M. J.; Rockman, S. P.

    2013-01-01

    The measurement of vaccine-induced humoral and CD4+ and CD8+ cellular immune responses represents an important correlate of vaccine efficacy. Accurate and reliable assays evaluating such responses are therefore critical during the clinical development phase of vaccines. T cells play a pivotal role both in coordinating the adaptive and innate immune responses and as effectors. During the assessment of cell-mediated immunity (CMI) in subjects participating in a large-scale influenza vaccine trial, we identified the expansion of an IFN-γ-producing CD3+CD4−CD8−γδ+ T cell population in the peripheral blood of 90/610 (15%) healthy subjects. The appearance of CD3+CD4−CD8−γδ+ T cells in the blood of subjects was transient and found to be independent of the study cohort, vaccine group, subject gender and ethnicity, and ex vivo restimulation conditions. Although the function of this population and relevance to vaccination are unclear, their inclusion in the total vaccine-specific T-cell response has the potential to confound data interpretation. It is thus recommended that when evaluating the induction of IFN-γ-producing CD4+ and CD8+ immune responses following vaccination, the CD3+CD4−CD8−γδ+ T cells are either excluded or separately enumerated from the overall frequency determination. PMID:24066003

  20. Ex vivo restimulation of human PBMC expands a CD3+CD4-CD8- γδ+ T cell population that can confound the evaluation of CD4 and CD8 T cell responses to vaccination.

    PubMed

    Sedgmen, B J; Papalia, L; Wang, L; Dyson, A R; McCallum, H A; Simson, C M; Pearse, M J; Maraskovsky, E; Hung, D; Eomois, P P; Hartel, G; Barnden, M J; Rockman, S P

    2013-01-01

    The measurement of vaccine-induced humoral and CD4(+) and CD8(+) cellular immune responses represents an important correlate of vaccine efficacy. Accurate and reliable assays evaluating such responses are therefore critical during the clinical development phase of vaccines. T cells play a pivotal role both in coordinating the adaptive and innate immune responses and as effectors. During the assessment of cell-mediated immunity (CMI) in subjects participating in a large-scale influenza vaccine trial, we identified the expansion of an IFN-γ-producing CD3(+)CD4(-)CD8(-) γδ (+) T cell population in the peripheral blood of 90/610 (15%) healthy subjects. The appearance of CD3(+)CD4(-)CD8(-) γδ (+) T cells in the blood of subjects was transient and found to be independent of the study cohort, vaccine group, subject gender and ethnicity, and ex vivo restimulation conditions. Although the function of this population and relevance to vaccination are unclear, their inclusion in the total vaccine-specific T-cell response has the potential to confound data interpretation. It is thus recommended that when evaluating the induction of IFN-γ-producing CD4(+) and CD8(+) immune responses following vaccination, the CD3(+)CD4(-)CD8(-) γδ (+) T cells are either excluded or separately enumerated from the overall frequency determination. PMID:24066003

  1. 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

  2. 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.…

  3. 18 CFR 367.2320 - Account 232, Accounts payable.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... payable. 367.2320 Section 367.2320 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY REGULATIONS UNDER THE PUBLIC UTILITY HOLDING COMPANY ACT OF 2005, FEDERAL... ACT Balance Sheet Chart of Accounts Current and Accrued Liabilities § 367.2320 Account 232,...

  4. Connecting Accounting and Communication: A Survey of Public Accounting Firms.

    ERIC Educational Resources Information Center

    Stowers, Robert H.; White, G. Thomas

    1999-01-01

    Reports on accounting professionals' self-assessment of their communication abilities (presentation, writing, interpersonal, and interviewing skills), factors contributing to these skills, and rankings of them. Shows that the development of effective communication skills, which are highly valued in public accounting firms, was not part of formal…

  5. 18 CFR 367.2320 - Account 232, Accounts payable.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... payable. 367.2320 Section 367.2320 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY REGULATIONS UNDER THE PUBLIC UTILITY HOLDING COMPANY ACT OF 2005, FEDERAL... ACT Balance Sheet Chart of Accounts Current and Accrued Liabilities § 367.2320 Account 232,...

  6. 18 CFR 367.2320 - Account 232, Accounts payable.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... payable. 367.2320 Section 367.2320 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY REGULATIONS UNDER THE PUBLIC UTILITY HOLDING COMPANY ACT OF 2005, FEDERAL... ACT Balance Sheet Chart of Accounts Current and Accrued Liabilities § 367.2320 Account 232,...

  7. 18 CFR 367.2320 - Account 232, Accounts payable.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... payable. 367.2320 Section 367.2320 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY REGULATIONS UNDER THE PUBLIC UTILITY HOLDING COMPANY ACT OF 2005, FEDERAL... ACT Balance Sheet Chart of Accounts Current and Accrued Liabilities § 367.2320 Account 232,...

  8. 18 CFR 367.2320 - Account 232, Accounts payable.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... payable. 367.2320 Section 367.2320 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY REGULATIONS UNDER THE PUBLIC UTILITY HOLDING COMPANY ACT OF 2005, FEDERAL... ACT Balance Sheet Chart of Accounts Current and Accrued Liabilities § 367.2320 Account 232,...

  9. 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

  10. 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

  11. 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

  12. Diagnosis of Tuberculosis by Trained African Giant Pouched Rats and Confounding Impact of Pathogens and Microflora of the Respiratory Tract

    PubMed Central

    Mgode, Georgies F.; Weetjens, Bart J.; Nawrath, Thorben; Cox, Christophe; Jubitana, Maureen; Machang'u, Robert S.; Cohen-Bacrie, Stéphan; Bedotto, Marielle; Drancourt, Michel; Schulz, Stefan

    2012-01-01

    Trained African giant-pouched rats (Cricetomys gambianus) can detect Mycobacterium tuberculosis and show potential for the diagnosis of tuberculosis (TB). However, rats' ability to discriminate between clinical sputum containing other Mycobacterium spp. and nonmycobacterial species of the respiratory tract is unknown. It is also unknown whether nonmycobacterial species produce odor similar to M. tuberculosis and thereby cause the detection of smear-negative sputum. Sputum samples from 289 subjects were analyzed by smear microscopy, culture, and rats. Mycobacterium spp. were isolated on Lowenstein-Jensen medium, and nonmycobacterial species were isolated on four different media. The odor from nonmycobacterial species from smear- and M. tuberculosis culture-negative sputa detected by ≥2 rats (“rat positive”) was analyzed by gas chromatography-mass spectrometry and compared to the M. tuberculosis odor. Rats detected 45 of 56 confirmed cases of TB, 4 of 5 suspected cases of TB, and 63 of 228 TB-negative subjects (sensitivity, 80.4%; specificity, 72.4%; accuracy, 73.9%; positive predictive value, 41.7%; negative predictive value, 93.8%). A total of 37 (78.7%) of 47 mycobacterial isolates were M. tuberculosis complex, with 75.7% from rat-positive sputa. Ten isolates were nontuberculous mycobacteria, one was M. intracellulare, one was M. avium subsp. hominissuis, and eight were unidentified. Rat-positive sputa with Moraxella catarrhalis, Streptococcus pneumoniae, Staphylococcus spp., and Enterococcus spp. were associated with TB. Rhodococcus, Nocardia, Streptomyces, Staphylococcus, and Candida spp. from rat-positive sputa did not produce M. tuberculosis-specific volatiles (methyl nicotinate, methyl para-anisate, and ortho-phenylanisole). Prevalence of Mycobacterium-related Nocardia and Rhodococcus in smear-negative sputa did not equal that of smear-negative mycobacteria (44.7%), of which 28.6% were rat positive. These findings and the absence of M. tuberculosis

  13. Diagnosis of tuberculosis by trained African giant pouched rats and confounding impact of pathogens and microflora of the respiratory tract.

    PubMed

    Mgode, Georgies F; Weetjens, Bart J; Nawrath, Thorben; Cox, Christophe; Jubitana, Maureen; Machang'u, Robert S; Cohen-Bacrie, Stéphan; Bedotto, Marielle; Drancourt, Michel; Schulz, Stefan; Kaufmann, Stefan H E

    2012-02-01

    Trained African giant-pouched rats (Cricetomys gambianus) can detect Mycobacterium tuberculosis and show potential for the diagnosis of tuberculosis (TB). However, rats' ability to discriminate between clinical sputum containing other Mycobacterium spp. and nonmycobacterial species of the respiratory tract is unknown. It is also unknown whether nonmycobacterial species produce odor similar to M. tuberculosis and thereby cause the detection of smear-negative sputum. Sputum samples from 289 subjects were analyzed by smear microscopy, culture, and rats. Mycobacterium spp. were isolated on Lowenstein-Jensen medium, and nonmycobacterial species were isolated on four different media. The odor from nonmycobacterial species from smear- and M. tuberculosis culture-negative sputa detected by ≥2 rats ("rat positive") was analyzed by gas chromatography-mass spectrometry and compared to the M. tuberculosis odor. Rats detected 45 of 56 confirmed cases of TB, 4 of 5 suspected cases of TB, and 63 of 228 TB-negative subjects (sensitivity, 80.4%; specificity, 72.4%; accuracy, 73.9%; positive predictive value, 41.7%; negative predictive value, 93.8%). A total of 37 (78.7%) of 47 mycobacterial isolates were M. tuberculosis complex, with 75.7% from rat-positive sputa. Ten isolates were nontuberculous mycobacteria, one was M. intracellulare, one was M. avium subsp. hominissuis, and eight were unidentified. Rat-positive sputa with Moraxella catarrhalis, Streptococcus pneumoniae, Staphylococcus spp., and Enterococcus spp. were associated with TB. Rhodococcus, Nocardia, Streptomyces, Staphylococcus, and Candida spp. from rat-positive sputa did not produce M. tuberculosis-specific volatiles (methyl nicotinate, methyl para-anisate, and ortho-phenylanisole). Prevalence of Mycobacterium-related Nocardia and Rhodococcus in smear-negative sputa did not equal that of smear-negative mycobacteria (44.7%), of which 28.6% were rat positive. These findings and the absence of M. tuberculosis

  14. Variable Selection for Confounder Control, Flexible Modeling and Collaborative Targeted Minimum Loss-Based Estimation in Causal Inference.

    PubMed

    Schnitzer, Mireille E; Lok, Judith J; Gruber, Susan

    2016-05-01

    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 [27]) 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

  15. Principals as Morally Accountable Leaders.

    ERIC Educational Resources Information Center

    Ehrich, Lisa Catherine

    2000-01-01

    Moral (rather than "corporate") accountability in education is essential; so is a human-centered leadership approach. Findings from an Australian study that investigated elementary principals' responsiveness to teachers' learning show how these leaders exercised their moral, professional, and contractual accountability to support a caring,…

  16. Making Educational Accountability More Democratic

    ERIC Educational Resources Information Center

    Ryan, Katherine

    2005-01-01

    Educational accountability is a fundamental right of citizens in a democratic society serving the public interest. The No Child Left Behind Act of 2001 holds states, school districts, public officials, educators, parents, and students accountable through auditable performance standards. At the same time, the lack of discussion about how to decide…

  17. Accountability in Education: Discussion Paper.

    ERIC Educational Resources Information Center

    Alberta Dept. of Education, Edmonton.

    To make the education system more open and accountable, Alberta (Canada) designated in 1994 the formation of an MLA (Member of Legislative Assembly) implementation team for educational accountability. The MLA team is consulting with Albertans about which results should be included in school reports, which measures should be used to report…

  18. 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…

  19. 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…

  20. Training within the Accounting Firm.

    ERIC Educational Resources Information Center

    Finch, Beth; And Others

    1991-01-01

    A survey received 509 responses from 2,000 randomly selected accounting employees about which training topics are receiving the most attention and who is receiving the training. Results prove that training has become an integral part of a certified public accountant's job; topics most often covered were tax related--individual and corporate income…

  1. Bringing Accountability to Elementary Art.

    ERIC Educational Resources Information Center

    Siegesmund, Richard

    2002-01-01

    Asserts that art is not an impractical "break" from serious learning but rather an essential part of that learning, focusing on the art classroom's traditional status as a refuge, the importance of accountability in art education, and benefits for classroom teachers. The paper explains that accountability does not mean the end of the art classroom…

  2. Machine Accounting. An Instructor's Guide.

    ERIC Educational Resources Information Center

    Gould, E. Noah, Ed.

    Designed to prepare students to operate the types of accounting machines used in many medium-sized businesses, this instructor's guide presents a full-year high school course in machine accounting covering 120 hours of instruction. An introduction for the instructor suggests how to adapt the guide to present a 60-hour module which would be…

  3. 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…

  4. Accounting Occupations Cluster Assessment Guide.

    ERIC Educational Resources Information Center

    Beaverton School District 48, OR.

    This assessment guide, developed by the Model Accounting Project at Aloha High School in the Beaverton, Oregon, school district, contains criteria statements that reflect factors deemed essential for quality instruction and overall effectiveness of the accounting program. The guide can be used by an instructor as a self-assessment instrument or by…

  5. 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…

  6. Accountability: the force behind empowerment.

    PubMed

    Horsfall, G A

    1996-11-01

    The first part of this article will focus on an examination of the more traditional practice of "process accountability," which typically uses policy-based methods that rely on the development, measurement, and reporting of standards. This will be followed up by an examination of the more ephemeral, though vastly more valuable and powerful "attitude" of "personal accountability." PMID:10162361

  7. 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…

  8. 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…

  9. 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…

  10. 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…

  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. Degrees of Success in Accounting.

    ERIC Educational Resources Information Center

    Bourner, Jill; Bourner, Tom

    1985-01-01

    Analysis of degree awards in Great Britain shows considerable inconsistency across disciplines and poor results in the accounting field. The implications for the labor market and accounting employment prospects are examined, and a reexamination of the application of equivalent standards across subjects is recommended. (MSE)

  13. 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…

  14. 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…

  15. 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…

  16. An indicator for effects of organic toxicants on lotic invertebrate communities: Independence of confounding environmental factors over an extensive river continuum.

    PubMed

    Beketov, Mikhail A; Liess, Matthias

    2008-12-01

    Distinguishing between effects of natural and anthropogenic environmental factors on ecosystems is a fundamental problem in environmental science. In river systems the longitudinal gradient of environmental factors is one of the most relevant sources of dissimilarity between communities that could be confounded with anthropogenic disturbances. To test the hypothesis that in macroinvertebrate communities the distribution of species' sensitivity to organic toxicants is independent of natural longitudinal factors, but depends on contamination with organic toxicants, we analysed the relationship between community sensitivity SPEAR(organic) (average community sensitivity to organic toxicants) and natural and anthropogenic environmental factors in a large-scale river system, from alpine streams to a lowland river. The results show that SPEAR(organic) is largely independent of natural longitudinal factors, but strongly dependent on contamination with organic toxicants (petrochemicals and synthetic surfactants). Usage of SPEAR(organic) as a stressor-specific longitude-independent measure will facilitate detection of community disturbance by organic toxicants. PMID:18547697

  17. Remedial habitat creation: does Nereis diversicolor play a confounding role in the colonisation and establishment of the pioneering saltmarsh plant, Spartina anglica?

    NASA Astrophysics Data System (ADS)

    Emmerson, M.

    2000-07-01

    Increasing concerns over global warming and expected sea level rises have led to the adoption of new coastal management strategies around the south-east coast of England. This paper explores the role played by the estuarine invertebrate Nereis diversicolor in limiting the colonisation and establishment of the invasive pioneering salt marsh plant, Spartina anglica. The biology of N. diversicolor is briefly reviewed and data from field experiments are presented demonstrating significant negative effects of worm abundance on transplanted S. anglica biomass. Laboratory-based experiments demonstrated significant negative effects of N. diversicolor abundance on the survival of S. anglica seeds transplanted to sediment cores. The importance of estuarine invertebrates in engineering the mudflat habitat may confound the foreseen ecosystem services and function provided by saltmarsh management schemes.

  18. The impact of synaptic conductance on action potential waveform: evoking realistic action potentials with a simulated synaptic conductance.

    PubMed

    Johnston, Jamie; Postlethwaite, Michael; Forsythe, Ian D

    2009-10-15

    Most current clamp studies trigger action potentials (APs) by step current injection through the recording electrode and assume that the resulting APs are essentially identical to those triggered by orthodromic synaptic inputs. However this assumption is not always valid, particularly when the synaptic conductance is of large magnitude and of close proximity to the axon initial segment. We addressed this question of similarity using the Calyx of Held/MNTB synapse; we compared APs evoked by long duration step current injections, short step current injections and orthodromic synaptic stimuli. Neither injected current protocol evoked APs that matched the evoked orthodromic AP waveform, showing differences in AP height, half-width and after-hyperpolarization. We postulated that this 'error' could arise from changes in the instantaneous conductance during the combined synaptic and AP waveforms, since the driving forces for the respective ionic currents are integrating and continually evolving over this time-course. We demonstrate that a simple Ohm's law manipulation of the EPSC waveform, which accounts for the evolving driving force on the synaptic conductance during the AP, produces waveforms that closely mimic those generated by physiological synaptic stimulation. This stimulation paradigm allows supra-threshold physiological stimulation (single stimuli or trains) without the variability caused by quantal fluctuation in transmitter release, and can be implemented without a specialised dynamic clamp system. Combined with pharmacological tools this method provides a reliable means to assess the physiological roles of postsynaptic ion channels without confounding affects from the presynaptic input. PMID:19560491

  19. Empirically Assessing the Importance of Characteristics of Accounting Students.

    ERIC Educational Resources Information Center

    Baker, William M.; McGregor, Calvert C.

    2000-01-01

    Three employer groups (n=117), 47 accounting faculty, and 63 students rated the following characteristics of potential employees: master's degree, overall and accounting grade point average, personal integrity, communication skills, energy/drive/enthusiasm, and appearance. Employers and faculty considered integrity extremely important; students…

  20. 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…

  1. Labour and Individual Learning Accounts: Let's Keep Talking.

    ERIC Educational Resources Information Center

    Thomson, Alastair

    1996-01-01

    Reviews British political party proposals for individual learning accounts, designed to give adults purchasing power for further education and training. Raises concerns about effects on existing employee development programs and other potential problems. (SK)

  2. 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

  3. Who Is Accountable for "Thoughtfulness"?

    ERIC Educational Resources Information Center

    Brown, Rexford

    1987-01-01

    Schools need more incentives to begin to produce more "thoughtfulness." As it is now they respond by "getting by" because they are only held accountable for minimal levels of achievement. Policymakers need to develop a different system of acccountability. (MD)

  4. 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)

  5. Accounting Internships: A Practical Framework.

    ERIC Educational Resources Information Center

    Henry, Linvol G.; And Others

    1988-01-01

    The authors describe a framework for administration and implementation of postsecondary internships in accounting. Topics covered include (1) qualifications, (2) duration, (3) timing, (4) granting credit and providing grades, and (5) evaluation criteria. Implementation guidelines are included. (CH)

  6. 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)

  7. Competency-Based Accounting Instruction

    ERIC Educational Resources Information Center

    Graham, John E.

    1977-01-01

    Shows how the proposed model (an individualized competency based learning system) can be used effectively to produce a course in accounting principles which adapts to different entering competencies and to different rates and styles of learning. (TA)

  8. Influence of histologic criteria and confounding factors in staging equivocal cases for microscopic perivesical tissue invasion (pT3a): an interobserver study among genitourinary pathologists.

    PubMed

    Ananthanarayanan, Vijayalakshmi; Pan, Yi; Tretiakova, Maria; Amin, Mahul B; Cheng, Liang; Epstein, Jonathan I; Grignon, David J; Hansel, Donna E; Jimenez, Rafael E; McKenney, Jesse K; Montironi, Rodolfo; Oliva, Esther; Osunkoya, Adeboye O; Rao, Priya; Reuter, Victor E; Ro, Jae Y; Shen, Steven S; Srigley, John R; Tsuzuki, Toyonori; Yao, Jorge L; Antic, Tatjana; Haber, Michael; Taxy, Jerome B; Paner, Gladell P

    2014-02-01

    Current oncology guidelines and clinical trials consider giving adjuvant chemotherapy to bladder cancer patients with at least microscopic perivesical tissue invasion (MPVTI) (≥pT3a) on cystectomy. The boundary of muscularis propria (MP) and perivesical tissue is commonly ill defined, and hence, when the tumor involves the interface, interpretation of MPVTI is likely to be subjective. In this study, 20 sets of static images that included 1 nontumoral bladder wall for defining MP-perivesical tissue boundary and 19 bladder cancer cases equivocal for MPVTI with confounding factors were sent to 17 expert genitourinary pathologists for review. The confounding factors were "histoanatomic," as defined by the irregular MP-perivesical tissue boundary, and "tumor related," such as fibrosis, dense inflammation, tumor cells at the edge of the outermost MP muscle bundle, and lymphovascular invasion. These equivocal cases were divided into 3 categories according to the following factors: (1) histoanatomic only (7/19), (2) histoanatomic+tumor related (7/19), and (3) tumor related only (5/19). Participating genitourinary pathologists used different criteria to assess MPVTI: (A) drawing a straight horizontal line using the outermost MP muscle bundle edge as the MP-perivesical tissue boundary reference (3/17); (B) drawing multiple straight lines interconnecting the outermost MP muscle bundle edges (9/17); (C) following the curves of every outermost MP muscle bundle edge (4/17). In category 1 cases, most pathologists who used the A criterion called for absence (6/7), whereas those who used the C criterion called for presence (5/7) of MPVTI, which resulted in disparity in 4/7 cases. There was no circumstance in which criteria A and C agreed on the presence or absence of MPVTI but was opposed by the B criterion in category 1 cases. Median pairwise agreement among all pathologists (regardless of criteria) for all cases (regardless of category) was only "fair" (κ=0.281). However, when

  9. 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. PMID:15453408

  10. 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.

  11. 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...

  12. 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...

  13. 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...

  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. 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.

  16. 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…

  17. 76 FR 53378 - Cost Accounting Standards: Accounting for Insurance Costs

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-26

    ... 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 effect... published the SDP, ``Accounting for Insurance Costs'' (71 FR 4335) which in particular, addressed the use...

  18. Incorporating Calculators into the Accounting Curriculum. Accounting I.

    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 Curriculum. The guide contains four 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 course…

  19. Performance measurement: the new accountability.

    PubMed

    Martin, L L; Kettner, P M

    1997-01-01

    Over the years, "accountability" in the human services has focused upon issues such as the legal framework, organizational management, financial responsibility, political concerns, and client inputs and expectations. Within the past decade, the meaning of "accountability" has been extended to the more dynamic organizational functions of "efficiency" and " effectiveness." Efficiency and effectiveness increasingly must be put to the tests of performance measurement and outcome evaluation. Forces outside the social work profession, including, among others, federal expectations and initiatives and the increased implementation of the concept of managed care, will ensure that efficiency and effectiveness will be central and highlighted concerns far into the future. This "new accountability" is demanded by the stakeholders in the nonprofit sector and by federal requirements built into the planning, funding, and implementation processes for nonprofits and for-profits alike. PMID:10166757

  20. A Liberal Account of Addiction

    PubMed Central

    Foddy, Bennett; Savulescu, Julian

    2014-01-01

    Philosophers and psychologists have been attracted to two differing accounts of addictive motivation. In this paper, we investigate these two accounts and challenge their mutual claim that addictions compromise a person’s self-control. First, we identify some incompatibilities between this claim of reduced self-control and the available evidence from various disciplines. A critical assessment of the evidence weakens the empirical argument for reduced autonomy. Second, we identify sources of unwarranted normative bias in the popular theories of addiction that introduce systematic errors in interpreting the evidence. By eliminating these errors, we are able to generate a minimal, but correct account, of addiction that presumes addicts to be autonomous in their addictive behavior, absent further evidence to the contrary. Finally, we explore some of the implications of this minimal, correct view. PMID:24659901

  1. 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

  2. A managerial accounting analysis of hospital costs.

    PubMed

    Frank, W G

    1976-01-01

    Variance analysis, an accounting technique, is applied to an eight-component model of hospital costs to determine the contribution each component makes to cost increases. The method is illustrated by application to data on total costs from 1950 to 1973 for all U.S. nongovernmental not-for-profit short-term general hospitals. The costs of a single hospital are analyzed and compared to the group costs. The potential uses and limitations of the method as a planning and research tool are discussed. PMID:965233

  3. 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. PMID:17411809

  4. Investigating the Potential Causal Relationship between Parental Knowledge and Youth Risky Behavior: A Propensity Score Analysis

    PubMed Central

    Lippold, Melissa A.; Coffman, Donna L.; Greenberg, Mark T.

    2014-01-01

    This longitudinal study aims to explore the potential causal relationship between parental knowledge and youth risky behavior among a sample of rural, early adolescents (84% White, 47% male). Using Inverse Propensity Weighting, the sample was adjusted by controlling for 33 potential confounding variables. Confounding variables include other aspects of the parent-child relationship, parental monitoring, demographic variables and earlier levels of problem behavior. The effect of parental knowledge was significant for youth substance and polysubstance use initiation, alcohol and cigarette use, attitudes towards substance use, and delinquency. Our results suggest that parental knowledge may be causally related to substance use during middle school, as the relationship between knowledge and youth outcomes remained after controlling for 33 different confounding variables. The discussion focuses on understanding issues of causality in parenting and intervention implications. PMID:24292890

  5. Investigating the potential causal relationship between parental knowledge and youth risky behavior: a propensity score analysis.

    PubMed

    Lippold, Melissa A; Coffman, Donna L; Greenberg, Mark T

    2014-12-01

    This longitudinal study aims to explore the potential causal relationship between parental knowledge and youth risky behavior among a sample of rural, early adolescents (84 % White, 47 % male). Using inverse propensity weighting, the sample was adjusted by controlling for 33 potential confounding variables. Confounding variables include other aspects of the parent-child relationship, parental monitoring, demographic variables, and earlier levels of problem behavior. The effect of parental knowledge was significant for youth substance and polysubstance use initiation, alcohol and cigarette use, attitudes towards substance use, and delinquency. Our results suggest that parental knowledge may be causally related to substance use during middle school, as the relationship between knowledge and youth outcomes remained after controlling for 33 different confounding variables. The discussion focuses on understanding issues of causality in parenting and intervention implications. PMID:24292890

  6. Accountability Is a Calculated Effort

    ERIC Educational Resources Information Center

    Vekich, Michael; Coborn, Daniel

    2004-01-01

    As part-time volunteer members who have few direct operational duties, board members constantly are bombarded with information on matters ranging from strategic plans to operating budgets to tuition rates to parking permits. In the end, it is they who are accountable for all activities that occur in their institutions and systems. The need for…

  7. 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.…

  8. Accountable Professional Practice in ELT

    ERIC Educational Resources Information Center

    Farmer, Frank

    2006-01-01

    Professionalism is widely thought to be desirable in ELT, and at the same time institutions are taking seriously the need to evaluate their teachers. This article presents a general approach to professionalism focused on the accountability of the professional to the client based on TESOL's (2000) classification of adult ELT within eight general…

  9. Accountability in Adult Farmer Education

    ERIC Educational Resources Information Center

    Callanan, Paul J.; Jackson, Dennis L.

    1978-01-01

    Two instructors write about some ideas they have implemented in their farm management program to help measure accountability. They describe the Minnesota Farm Business Analysis, use of the analysis summary book, income tax management, and budgeting and cash flow planning. (MF)

  10. 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…

  11. Accounting Procedures for Student Organizations.

    ERIC Educational Resources Information Center

    California State Dept. of Education, Sacramento.

    This two-part handbook presents information on accounting procedures for student organizations, with a focus on the laws, policies, and procedures that affect student body organizations. Part 1 contains information about: (1) legal status of a school's student body organization; (2) principles governing student body finance; (3) administration of…

  12. Accountability--A Historical Perspective.

    ERIC Educational Resources Information Center

    Keefover, Karen Shade

    1983-01-01

    Asserts that existing accountability policies assume that a single behaviorist theory is the one best system for effective education. Examines the pitfalls of the one-system approach through the examples of John Stuart Mill's utilitarian upbringing and "Gradgrindism" in Charles Dickens' novel "Hard Times." (SK)

  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. Kant's Account of Moral Education

    ERIC Educational Resources Information Center

    Giesinger, Johannes

    2012-01-01

    While Kant's pedagogical lectures present an account of moral education, his theory of freedom and morality seems to leave no room for the possibility of an education for freedom and morality. In this paper, it is first shown that Kant's moral philosophy and his educational philosophy are developed within different theoretical paradigms: whereas…

  15. 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…

  16. Accountability, Diagnostics, and Information Technology

    ERIC Educational Resources Information Center

    Doyle, Denis P.

    2004-01-01

    This article argues that while accountability is the watchword of overseers, too often it is the bane of the overseen. At its best, it reflects a prudent concern for good stewardship and responsible management of necessarily scarce resources; at its worst, it becomes a form of mindless hector-ing, in which careful oversight gives way to invective…

  17. Accounting for What Youngsters Learn.

    ERIC Educational Resources Information Center

    Bell, Terrel H.

    In this speech, the author discusses the use of the management by objectives (MBO) approach as a means for accomplishing accountability. He traces the steps to be taken by participants -- from superintendent to school staff -- in implementing an MBO program. (JF)

  18. Trading Accountability for Greater Flexibility.

    ERIC Educational Resources Information Center

    Sanders, Ted

    1991-01-01

    Describes the plight of two risk-taking principals who drastically improved their schools' academic performance, only to be defeated by bureaucratic regulations and business-as-usual attitudes. Allowing schools greater flexibility in exchange for increased accountability will free talented teachers and principals to restructure schools and solve…

  19. Holding Schools Accountable for Equity.

    ERIC Educational Resources Information Center

    Olsen, Laurie

    2001-01-01

    Good reforms can have harmful results if equity effects are ignored. As California implements its accountability system, certain questions must be addressed concerning the system's data use, measurement features (consistency, meaningfulness, achievement growth, achievement gaps among groups), instructional improvement focus, incentives for…

  20. NCEO Framework for Educational Accountability.

    ERIC Educational Resources Information Center

    Ysseldyke, Jim; Krentz, Jane; Elliott, Judy; Thurlow, Martha; Erickson, Ronald; Moore, Michael

    This report describes how the National Center on Educational Outcomes (NCEO) Framework for Educational Accountability, which specifies outcomes and indicators for six developmental levels (ages three and six, grades four, eight, and twelve, and post-school), can be used to implement parts of the National Association of State Directors of Special…

  1. Academic Accountability and State Intervention.

    ERIC Educational Resources Information Center

    Duncan, John W.

    This speech discusses the national emerging trend toward state intervention in local educational processes as part of the academic accountability movement. It provides examples of reforms and improvements whereby state intervention furnished local school improvement. The address focuses on state intervention in Jersey City, New Jersey; predicts…

  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. Program Accountability: "The State Audit".

    ERIC Educational Resources Information Center

    Charles, Richard F.

    Guidelines, based on the California Education Code and the California Community College Student Attendance Accounting Manual, are presented as an aid to program-level administrators and staff preparing for a state audit of program attendance records. After introductory material examining the role of average daily attendance (ADA) and weekly…

  4. 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)

  5. JSC interactive basic accounting system

    NASA Technical Reports Server (NTRS)

    Spitzer, J. F.

    1978-01-01

    Design concepts for an interactive basic accounting system (IBAS) are considered in terms of selecting the design option which provides the best response at the lowest cost. Modeling the IBAS workload and applying this workload to a U1108 EXEC 8 based system using both a simulation model and the real system is discussed.

  6. Accountability: Stepping Stones to Success

    ERIC Educational Resources Information Center

    Loy, Darcy

    2010-01-01

    Lack of accountability is a leading topic in today's workforce. It costs corporate America billions of dollars each year and has financial impact on educational institutions as well. From employee theft to poor production of product and inefficiency, it is a serious problem. Facilities leaders need to take ownership and strive to implement…

  7. 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)

  8. 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:…

  9. 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…

  10. From Transactional to Transformational Accounting.

    ERIC Educational Resources Information Center

    Cooper, Bruce S.; Randall, E. Vance

    1998-01-01

    Accurate transactional financial data are necessary for governmental compliance; transformational information is crucial for measuring and improving school performance. Some districts are shifting from a systems to a service, focus, from partial to full-cost accounting, from centralized to decentralized reporting procedures and facilities, and…

  11. Accounting. Occupational Competency Analysis Profile.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. Vocational Instructional Materials Lab.

    This Accounting Occupational Competency Analysis Profile (OCAP) is one of a series of competency lists, verified by expert workers, that have evolved from a modified DACUM (Developing a Curriculum) job analysis process involving business, industry, labor, and community agency representatives from throughout Ohio. This OCAP identifies the…

  12. Managerial Accounting. Course Administrative Manual.

    ERIC Educational Resources Information Center

    Central Michigan Univ., Mount Pleasant. Inst. for Personal and Career Development.

    This manual is part of the materials for a college-level programmed course in managerial accounting and intended to aid instructors in helping students to work their way through the self-instructional study guide around which the course is organized. The manual describes the various materials and components used in the self-instructional sequence…

  13. Accounting. Ohio's Competency Analysis Profile.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. Vocational Instructional Materials Lab.

    Developed through a modified DACUM (Developing a Curriculum) process involving business, industry, labor, and community agency representatives in Ohio, this document is a comprehensive and verified employer competency profile for accounting occupations. The list contains units (with and without subunits), competencies, and competency builders that…

  14. Incivility in the Accounting Classroom

    ERIC Educational Resources Information Center

    Swinney, Laurie; Elder, Bruce; Seaton, Lloyd

    2010-01-01

    Classroom incivility is any action that interferes with a harmonious and cooperative learning atmosphere in the classroom (Feldman, 2001). We compared the perceptions of accounting faculty to the perceptions of cross-disciplinary faculty relating to both the definition of student actions as incivility and the occurrence of incivility. We also…

  15. Increasing accountability to drive improvement.

    PubMed

    Abbott, John G

    2012-01-01

    Governments need to be more strategic in their approach to healthcare and ensure greater accountability for the performance of their health systems. They can start by agreeing on a pan-Canadian vision for the health of Canadians and the services to be provided, accompanied by explicit policy goals, evidence-based performance targets, and more transparent public reporting. PMID:23387134

  16. 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…

  17. 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…

  18. Converting accounts receivable into cash.

    PubMed

    Folk, M D; Roest, P R

    1995-09-01

    In recent years, increasing numbers of healthcare providers have converted their accounts receivable into cash through a process called securitization. This practice has gained popularity because it provides a means to raise capital necessary to healthcare organizations. Although securitization transactions can be complex, they may provide increased financial flexibility to providers as they prepare for continuing change in the healthcare industry. PMID:10145096

  19. Why it is too early to lose control in accounts of item-specific proportion congruency effects.

    PubMed

    Bugg, Julie M; Jacoby, Larry L; Chanani, Swati

    2011-06-01

    The item-specific proportion congruency (ISPC) effect is the finding of attenuated interference for mostly incongruent as compared to mostly congruent items. A debate in the Stroop literature concerns the mechanisms underlying this effect. Noting a confound between proportion congruency and contingency, Schmidt and Besner (2008) suggested that ISPC effects are entirely contingency based. We introduce a broader theoretical analysis that points to the contribution of both contingency and item-specific control mechanisms. Our analysis highlights that proportion congruency is not confounded with contingency when the relevant dimension functions as the ISPC signal, and predicts that evidence of item-specific control should be obtained by shifting the signal from the irrelevant to the relevant dimension. We examine this prediction in a picture-word Stroop paradigm. When the relevant dimension functions as the ISPC signal (Experiments 1 and 2), evidence of control is obtained. When the irrelevant dimension functions as the ISPC signal (Experiment 3), contingencies can account for the ISPC effect. These patterns support our theoretical analysis, challenge a pure contingency account, and favor the inclusion of control in accounts of ISPC effects. PMID:20718569

  20. Educational Accountability and Evaluation. PREP-35.

    ERIC Educational Resources Information Center

    Krystal, Sheila; Henrie, Samuel

    Educational accountability is treated as a philosophy and as a means of introducing system into an educational enterprise. The philosophy of accountability is discussed as to the demand for accountability, the possibility of using accountability as a political tool, the promise made by accountability and whether the promise can be kept, difficult…

  1. 31 CFR 515.319 - Blocked account.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Blocked account. 515.319 Section 515... § 515.319 Blocked account. The term blocked account shall mean an account in which any designated national has an interest, with respect to which account payments, transfers or withdrawals or...

  2. 31 CFR 515.319 - Blocked account.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Blocked account. 515.319 Section 515... § 515.319 Blocked account. The term blocked account shall mean an account in which any designated national has an interest, with respect to which account payments, transfers or withdrawals or...

  3. 50 CFR 259.36 - CCF accounts.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 9 2011-10-01 2011-10-01 false CCF accounts. 259.36 Section 259.36....36 CCF accounts. (a) General: Each CCF account in each scheduled depository shall have an account number, which must be reflected on the reports required by § 259.35. All CCF accounts shall be...

  4. 50 CFR 259.36 - CCF accounts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 7 2010-10-01 2010-10-01 false CCF accounts. 259.36 Section 259.36....36 CCF accounts. (a) General: Each CCF account in each scheduled depository shall have an account number, which must be reflected on the reports required by § 259.35. All CCF accounts shall be...

  5. 12 CFR 561.33 - Note account.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 5 2011-01-01 2011-01-01 false Note account. 561.33 Section 561.33 Banks and... SAVINGS ASSOCIATIONS § 561.33 Note account. The term note account means a note, subject to the right of... States Treasury Department regulations. Note accounts are not savings accounts or savings deposits....

  6. 31 CFR 500.319 - Blocked account.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Blocked account. 500.319 Section 500... § 500.319 Blocked account. The term blocked account shall mean an account in which any designated national has an interest, with respect to which account payments, transfers or withdrawals of...

  7. 12 CFR 561.33 - Note account.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 5 2010-01-01 2010-01-01 false Note account. 561.33 Section 561.33 Banks and... SAVINGS ASSOCIATIONS § 561.33 Note account. The term note account means a note, subject to the right of... States Treasury Department regulations. Note accounts are not savings accounts or savings deposits....

  8. Arkansas' Curriculum Guide. Competency Based Computerized Accounting.

    ERIC Educational Resources Information Center

    Arkansas State Dept. of Education, Little Rock. Div. of Vocational, Technical and Adult Education.

    This guide contains the essential parts of a total curriculum for a one-year secondary-level course in computerized accounting. Addressed in the individual sections of the guide are the following topics: the complete accounting cycle, computer operations for accounting, computerized accounting and general ledgers, computerized accounts payable,…

  9. 7 CFR 1902.15 - Closing accounts.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 12 2012-01-01 2012-01-01 false Closing accounts. 1902.15 Section 1902.15 Agriculture... SUPERVISED BANK ACCOUNTS Supervised Bank Accounts of Loan, Grant, and Other Funds § 1902.15 Closing accounts... consent (and of another lender or grantor, if involved) to close the supervised bank account in...

  10. 7 CFR 1902.15 - Closing accounts.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 12 2014-01-01 2013-01-01 true Closing accounts. 1902.15 Section 1902.15 Agriculture... SUPERVISED BANK ACCOUNTS Supervised Bank Accounts of Loan, Grant, and Other Funds § 1902.15 Closing accounts... consent (and of another lender or grantor, if involved) to close the supervised bank account in...

  11. 7 CFR 1902.15 - Closing accounts.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 12 2011-01-01 2011-01-01 false Closing accounts. 1902.15 Section 1902.15 Agriculture... SUPERVISED BANK ACCOUNTS Supervised Bank Accounts of Loan, Grant, and Other Funds § 1902.15 Closing accounts... consent (and of another lender or grantor, if involved) to close the supervised bank account in...

  12. 7 CFR 1902.15 - Closing accounts.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 12 2010-01-01 2010-01-01 false Closing accounts. 1902.15 Section 1902.15 Agriculture... SUPERVISED BANK ACCOUNTS Supervised Bank Accounts of Loan, Grant, and Other Funds § 1902.15 Closing accounts... consent (and of another lender or grantor, if involved) to close the supervised bank account in...

  13. 7 CFR 1902.15 - Closing accounts.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 12 2013-01-01 2013-01-01 false Closing accounts. 1902.15 Section 1902.15 Agriculture... SUPERVISED BANK ACCOUNTS Supervised Bank Accounts of Loan, Grant, and Other Funds § 1902.15 Closing accounts... consent (and of another lender or grantor, if involved) to close the supervised bank account in...

  14. 14 CFR 1-6 - Accounting entities.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false Accounting entities. Sec. 1-6 Section Sec... General Accounting Provisions Sec. 1-6 Accounting entities. (a) Separate accounting records shall be... forth above. (c) The records for each required accounting entity shall be maintained with...

  15. 14 CFR 2-4 - Accounting period.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false Accounting period. Sec. 2-4 Section Sec. 2... Accounting Provisions Sec. 2-4 Accounting period. (a) The accounting year of each air carrier subject to this... settlement with debtors or creditors. (c) Expenditures incurred during the current accounting year...

  16. REASSESSMENT OF TSUNAMI HAZARD IN THE CITY OF IQUIQUE, CHILE, AFTER THE PISAGUA EARTHQUAKE OF APRIL 2014 In the present contribution, we will reassess the tsunami hazard for the North of Chile taking into account the occurrence of the recent events, focusing on the potential tsunami impact that a worse case scenario could produce in the city of Iquique.

    NASA Astrophysics Data System (ADS)

    Cienfuegos, R.; Suarez, L.; Aránguiz, R.; Gonzalez, G.; González-Carrasco, J. F.; Catalan, P. A.; Dominguez, J. C.; Tomita, T.

    2014-12-01

    On April 1st2014 a 8.1 Mw Earthquake occurred at 23:46:50 UTC (20:46:50 local time) with its epicenter located off the coast of Pisagua, 68 km north of the city of Iquique (An et al., 2014). The potential risk of earthquake and tsunami in this area was widely recognized by the scientific community (Chlieh et al., 2004). Nevertheless, the energy released by this earthquake and the associated slip distribution was much less than expected. In the present contribution, we will reassess the tsunami hazard for the North of Chile taking into account the occurrence of the recent events, focusing on the potential impact that a worse case scenario could produce in the city of Iquique. For that purpose, an updated tsunami source will be derived using updated information on the seismic and co-seismic tectonic displacements that is available from historical, geological information, and the dense GPS and seismometer networks available in the North of Chile. The updated tsunami source will be used to generate initial conditions for a tsunami and analyze the following aspects: i) large scale hydrodynamics, ii) arrival times, maximum flow depths, and inundation area, iii) potential impact on the port of Iquique, and more specifically on the container's drift that the tsunami could produce. This analysis is essential to reassess tsunami hazard in Iquique, evaluate evacuation plans and mitigation options regarding the port operation. Tsunami propagation and inundation will be conducted using the STOC model (Tomita and Honda, 2010), and a high resolution Lidar topographic database. ReferencesAn, C. et al. (2014). Tsunami source and its validation of the 2014 Iquique, Chile Earthquake, Geophys. Res. Lett., 41, doi:10.1002/2014GL060567. Chlieh, et al. (2004). Crustal deformation and fault slip during the seismic cycle in the north Chile subduction zone, from GPS and INSAR observations, Geophys J. Int., 158(2), 695-711, 10.1111/j.1365-246X.2004.02326.x. Tomita, T., & Honda, K. (2010

  17. The OECD as Pivot of the Emerging Global Educational Accountability Regime: How Accountable Are the Accountants?

    ERIC Educational Resources Information Center

    Meyer, Heinz-Dieter

    2014-01-01

    Background/Context: PISA has catapulted the OECD- an organization whose mission is the global growth of market economies-to a central role in international education policy making, rivaling and sometimes outdoing the various national governments in influence. While claiming scientific evidence as the basis for the accountability regime it…

  18. 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... Standard (CAS) 412, ``Composition and Measurement of Pension Cost,'' and CAS 413, ``Adjustment and... the final rule that revised Cost Accounting Standard (CAS) 412, ``Composition and Measurement...

  19. Adjusting for confounding effects of treatment switching in a randomized phase II study of dabrafenib plus trametinib in BRAF V600+ metastatic melanoma.

    PubMed

    Latimer, Nicholas R; Amonkar, Mayur M; Stapelkamp, Ceilidh; Sun, Peng

    2015-12-01

    Patients with BRAF V600E mutation-positive melanoma who were assigned to 150 mg dabrafenib twice daily combined with 2 mg trametinib once daily in a phase I/II study showed a median overall survival (OS) of 23.8 months, compared with 20.2 months for patients assigned to dabrafenib alone [hazard ratio (HR)=0.73, 95% confidence interval (CI) 0.43-1.24; data cutoff March 2013], on the basis of an intention-to-treat analysis. Because patients assigned to dabrafenib monotherapy were allowed to switch to combination therapy upon disease progression, we attempted to adjust for confounding effects on OS. Randomization-based adjustment methods, Rank Preserving Structural Failure Time Models and the Iterative Parameter Estimation algorithm, were used. Two analyses, 'treatment group' (assumes that treatment effect continues beyond treatment discontinuation) and 'on treatment' (assumes that the treatment effect disappears upon treatment discontinuation), were used to test assumptions on the durability of the treatment effect. A total of 45/54 (83%) patients assigned to dabrafenib monotherapy switched to the trametinib/dabrafenib combination. Adjusted OS HRs ranged from 0.47 to 0.50, depending on the analysis, compared with the unadjusted OS HR of 0.73. CIs continued to cross 1.00; thus, adjusted estimates did not provide statistically significant evidence of a treatment benefit on survival. Reduction of HRs after adjusting for the effect of treatment switching suggests that the intention-to-treat analysis underestimates the effect of dabrafenib plus trametinib on OS, although several factors, such as small trial size and methodological assumptions, affect the certainty of the conclusions. PMID:26340744

  20. Observed effects of “distributional learning” may not relate to the number of peaks. A test of “dispersion” as a confounding factor

    PubMed Central

    Wanrooij, Karin; Boersma, Paul; Benders, Titia

    2015-01-01

    Distributional learning of speech sounds is learning from simply being exposed to frequency distributions of speech sounds in one’s surroundings. In laboratory settings, the mechanism has been reported to be discernible already after a few minutes of exposure, in both infants and adults. These “effects of distributional training” have traditionally been attributed to the difference in the number of peaks between the experimental distribution (two peaks) and the control distribution (one or zero peaks). However, none of the earlier studies fully excluded a possibly confounding effect of the dispersion in the distributions. Additionally, some studies with a non-speech control condition did not control for a possible difference between processing speech and non-speech. The current study presents an experiment that corrects both imperfections. Spanish listeners were exposed to either a bimodal distribution encompassing the Dutch contrast /ɑ/∼/a/ or a unimodal distribution with the same dispersion. Before and after training, their accuracy of categorization of [ɑ]- and [a]-tokens was measured. A traditionally calculated p-value showed no significant difference in categorization improvement between bimodally and unimodally trained participants. Because of this null result, a Bayesian method was used to assess the odds in favor of the null hypothesis. Four different Bayes factors, each calculated on a different belief in the truth value of previously found effect sizes, indicated the absence of a difference between bimodally and unimodally trained participants. The implication is that “effects of distributional training” observed in the lab are not induced by the number of peaks in the distributions. PMID:26441719