WorldWideScience

Sample records for tissues confounds efforts

  1. Leading Efforts to Increase Organ Donation Through Professionalization of Organ Procurement Organizations and Establishment of Organ and Tissue Donor Registries.

    Science.gov (United States)

    Vertanous, T; Czer, L S C; de Robertis, M; Kiankhooy, A; Kobashigawa, J; Esmailian, F; Trento, A

    2016-01-01

    The influence of new donor registrations through the California Organ and Tissue Donor Registry on the local OneLegacy Organ Procurement Organization (OPO) was examined during a 6-year period. Publicly available data from Donate Life America for California were examined for the 6 calendar years of 2009-2014. Performance data from OneLegacy for the same 6 years for organ donors and number of transplants were also examined. The donor designation rate (DDR) was defined as the rate at which new individuals joined the state donor registry as a percentage of all driver licenses and ID cards issued within a calendar year. The total donor designation (TDD) was defined as the sum of the new and existing people who were registered organ donors. Donor designation share (DDS) was the total number of designated donors as a percentage of all residents of the state who were ≥18 years old. The business practices and educational efforts of the OneLegacy OPO were examined as well. In California, from 2009 through 2014, the DDR was 25.5%-28%. When added to the existing donor registrations, the TDD and DDS increased each year from 2009 through 2014. With the current level of growth, it is projected that California will be able to reach a DDS of 50% by 2017. For the OneLegacy OPO, designated donors from the California Organ and Tissue Donor Registry made up 15% of the total donations in 2009, and 39% of the total donations in 2014, increasing by ∼5% each year since 2009. By increasing professionalization and transparency, and widening its educational and training efforts, OneLegacy was able to take advantage of an increasing percentage of donors who were designated donors and to increase the overall number of donors and organs transplanted, becoming one of the largest OPOs in the nation. This can be a model for OPOs in other donor service areas, and it may set the stage for the United States to serve as an example to the global community in the practice of organ donation. Copyright

  2. Marine oils: Complex, confusing, confounded?

    Directory of Open Access Journals (Sweden)

    Benjamin B. Albert

    2016-09-01

    Full Text Available Marine oils gained prominence following the report that Greenland Inuits who consumed a high-fat diet rich in long-chain n-3 polyunsaturated fatty acids (PUFAs also had low rates of cardiovascular disease. Marine n-3 PUFAs have since become a billion dollar industry, which will continue to grow based on current trends. However, recent systematic reviews question the health benefits of marine oil supplements, particularly in the prevention of cardiovascular disease. Marine oils constitute an extremely complex dietary intervention for a number of reasons: i the many chemical compounds they contain; ii the many biological processes affected by n-3 PUFAs; iii their tendency to deteriorate and form potentially toxic primary and secondary oxidation products; and iv inaccuracy in the labelling of consumer products. These complexities may confound the clinical literature, limiting the ability to make substantive conclusions for some key health outcomes. Thus, there is a pressing need for clinical trials using marine oils whose composition has been independently verified and demonstrated to be minimally oxidised. Without such data, it is premature to conclude that n-3 PUFA rich supplements are ineffective.

  3. 'Mechanical restraint-confounders, risk, alliance score'

    DEFF Research Database (Denmark)

    Deichmann Nielsen, Lea; Bech, Per; Hounsgaard, Lise

    2017-01-01

    . AIM: To clinically validate a new, structured short-term risk assessment instrument called the Mechanical Restraint-Confounders, Risk, Alliance Score (MR-CRAS), with the intended purpose of supporting the clinicians' observation and assessment of the patient's readiness to be released from mechanical...... restraint. METHODS: The content and layout of MR-CRAS and its user manual were evaluated using face validation by forensic mental health clinicians, content validation by an expert panel, and pilot testing within two, closed forensic mental health inpatient units. RESULTS: The three sub-scales (Confounders......, Risk, and a parameter of Alliance) showed excellent content validity. The clinical validations also showed that MR-CRAS was perceived and experienced as a comprehensible, relevant, comprehensive, and useable risk assessment instrument. CONCLUSIONS: MR-CRAS contains 18 clinically valid items...

  4. Resting-state FMRI confounds and cleanup

    Science.gov (United States)

    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

  5. Sensitivity analysis for the effects of multiple unmeasured confounders.

    Science.gov (United States)

    Groenwold, Rolf H H; Sterne, Jonathan A C; Lawlor, Debbie A; Moons, Karel G M; Hoes, Arno W; Tilling, Kate

    2016-09-01

    Observational studies are prone to (unmeasured) confounding. Sensitivity analysis of unmeasured confounding typically focuses on a single unmeasured confounder. The purpose of this study was to assess the impact of multiple (possibly weak) unmeasured confounders. Simulation studies were performed based on parameters estimated from the British Women's Heart and Health Study, including 28 measured confounders and assuming no effect of ascorbic acid intake on mortality. In addition, 25, 50, or 100 unmeasured confounders were simulated, with various mutual correlations and correlations with measured confounders. The correlated unmeasured confounders did not need to be strongly associated with exposure and outcome to substantially bias the exposure-outcome association at interest, provided that there are sufficiently many unmeasured confounders. Correlations between unmeasured confounders, in addition to the strength of their relationship with exposure and outcome, are key drivers of the magnitude of unmeasured confounding and should be considered in sensitivity analyses. However, if the unmeasured confounders are correlated with measured confounders, the bias yielded by unmeasured confounders is partly removed through adjustment for the measured confounders. Discussions of the potential impact of unmeasured confounding in observational studies, and sensitivity analyses to examine this, should focus on the potential for the joint effect of multiple unmeasured confounders to bias results. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Bias formulas for sensitivity analysis of unmeasured confounding for general outcomes, treatments, and confounders.

    Science.gov (United States)

    Vanderweele, Tyler J; Arah, Onyebuchi A

    2011-01-01

    Uncontrolled confounding in observational studies gives rise to biased effect estimates. Sensitivity analysis techniques can be useful in assessing the magnitude of these biases. In this paper, we use the potential outcomes framework to derive a general class of sensitivity-analysis formulas for outcomes, treatments, and measured and unmeasured confounding variables that may be categorical or continuous. We give results for additive, risk-ratio and odds-ratio scales. We show that these results encompass a number of more specific sensitivity-analysis methods in the statistics and epidemiology literature. The applicability, usefulness, and limits of the bias-adjustment formulas are discussed. We illustrate the sensitivity-analysis techniques that follow from our results by applying them to 3 different studies. The bias formulas are particularly simple and easy to use in settings in which the unmeasured confounding variable is binary with constant effect on the outcome across treatment levels.

  7. Tissue

    Directory of Open Access Journals (Sweden)

    David Morrissey

    2012-01-01

    Full Text Available Purpose. In vivo gene therapy directed at tissues of mesenchymal origin could potentially augment healing. We aimed to assess the duration and magnitude of transene expression in vivo in mice and ex vivo in human tissues. Methods. Using bioluminescence imaging, plasmid and adenoviral vector-based transgene expression in murine quadriceps in vivo was examined. Temporal control was assessed using a doxycycline-inducible system. An ex vivo model was developed and optimised using murine tissue, and applied in ex vivo human tissue. Results. In vivo plasmid-based transgene expression did not silence in murine muscle, unlike in liver. Although maximum luciferase expression was higher in muscle with adenoviral delivery compared with plasmid, expression reduced over time. The inducible promoter cassette successfully regulated gene expression with maximum levels a factor of 11 greater than baseline. Expression was re-induced to a similar level on a temporal basis. Luciferase expression was readily detected ex vivo in human muscle and tendon. Conclusions. Plasmid constructs resulted in long-term in vivo gene expression in skeletal muscle, in a controllable fashion utilising an inducible promoter in combination with oral agents. Successful plasmid gene transfection in human ex vivo mesenchymal tissue was demonstrated for the first time.

  8. Effects of honey to mobilize endogenous stem cells in efforts intestinal and ovarian tissue regeneration in rats with protein energy malnutrition

    Directory of Open Access Journals (Sweden)

    R. Heru Prasetyo

    2016-05-01

    Conclusions: Expression of CD34+ and CD45+, which significantly different in treatment 2 (2. Furthermore, increase of immune response (decrease Hsp70 expression and increased PGE2 in intestinal tissue. Increased immune response causes expression of GDF-9 in ovarian tissue. Decreased of Hsp70 expression, increased PGE2 and increased GDF-9 followed the process of regeneration of the intestinal and ovarian tissue.

  9. Effortful echolalia.

    Science.gov (United States)

    Hadano, K; Nakamura, H; Hamanaka, T

    1998-02-01

    We report three cases of effortful echolalia in patients with cerebral infarction. The clinical picture of speech disturbance is associated with Type 1 Transcortical Motor Aphasia (TCMA, Goldstein, 1915). The patients always spoke nonfluently with loss of speech initiative, dysarthria, dysprosody, agrammatism, and increased effort and were unable to repeat sentences longer than those containing four or six words. In conversation, they first repeated a few words spoken to them, and then produced self initiated speech. The initial repetition as well as the subsequent self initiated speech, which were realized equally laboriously, can be regarded as mitigated echolalia (Pick, 1924). They were always aware of their own echolalia and tried to control it without effect. These cases demonstrate that neither the ability to repeat nor fluent speech are always necessary for echolalia. The possibility that a lesion in the left medial frontal lobe, including the supplementary motor area, plays an important role in effortful echolalia is discussed.

  10. Comorbidities, confounders, and the white matter transcriptome in chronic alcoholism.

    Science.gov (United States)

    Sutherland, Greg T; Sheedy, Donna; Sheahan, Pam J; Kaplan, Warren; Kril, Jillian J

    2014-04-01

    Alcohol abuse is the world's third leading cause of disease and disability, and one potential sequel of chronic abuse is alcohol-related brain damage (ARBD). This clinically manifests as cognitive dysfunction and pathologically as atrophy of white matter (WM) in particular. The mechanism linking chronic alcohol intoxication with ARBD remains largely unknown but it is also complicated by common comorbidities such as liver damage and nutritional deficiencies. Liver cirrhosis, in particular, often leads to hepatic encephalopathy (HE), a primary glial disease. In a novel transcriptomic study, we targeted the WM only of chronic alcoholics in an attempt to tease apart the pathogenesis of ARBD. Specifically, in alcoholics with and without HE, we explored both the prefrontal and primary motor cortices, 2 regions that experience differential levels of neuronal loss. Our results suggest that HE, along with 2 confounders, gray matter contamination, and low RNA quality are major drivers of gene expression in ARBD. All 3 exceeded the effects of alcohol itself. In particular, low-quality RNA samples were characterized by an up-regulation of translation machinery, while HE was associated with a down-regulation of mitochondrial energy metabolism pathways. The findings in HE alcoholics are consistent with the metabolic acidosis seen in this condition. In contrast non-HE alcoholics had widespread but only subtle changes in gene expression in their WM. Notwithstanding the latter result, this study demonstrates that significant confounders in transcriptomic studies of human postmortem brain tissue can be identified, quantified, and "removed" to reveal disease-specific signals. Copyright © 2014 by the Research Society on Alcoholism.

  11. Predictive modelling using neuroimaging data in the presence of confounds.

    Science.gov (United States)

    Rao, Anil; Monteiro, Joao M; Mourao-Miranda, Janaina

    2017-04-15

    When training predictive models from neuroimaging data, we typically have available non-imaging variables such as age and gender that affect the imaging data but which we may be uninterested in from a clinical perspective. Such variables are commonly referred to as 'confounds'. In this work, we firstly give a working definition for confound in the context of training predictive models from samples of neuroimaging data. We define a confound as a variable which affects the imaging data and has an association with the target variable in the sample that differs from that in the population-of-interest, i.e., the population over which we intend to apply the estimated predictive model. The focus of this paper is the scenario in which the confound and target variable are independent in the population-of-interest, but the training sample is biased due to a sample association between the target and confound. We then discuss standard approaches for dealing with confounds in predictive modelling such as image adjustment and including the confound as a predictor, before deriving and motivating an Instance Weighting scheme that attempts to account for confounds by focusing model training so that it is optimal for the population-of-interest. We evaluate the standard approaches and Instance Weighting in two regression problems with neuroimaging data in which we train models in the presence of confounding, and predict samples that are representative of the population-of-interest. For comparison, these models are also evaluated when there is no confounding present. In the first experiment we predict the MMSE score using structural MRI from the ADNI database with gender as the confound, while in the second we predict age using structural MRI from the IXI database with acquisition site as the confound. Considered over both datasets we find that none of the methods for dealing with confounding gives more accurate predictions than a baseline model which ignores confounding, although

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

    NARCIS (Netherlands)

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

    2016-01-01

    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

  13. Confounding and exposure measurement error in air pollution epidemiology

    NARCIS (Netherlands)

    Sheppard, L.; Burnett, R.T.; Szpiro, A.A.; Kim, J.Y.; Jerrett, M.; Pope, C.; Brunekreef, B.|info:eu-repo/dai/nl/067548180

    2012-01-01

    Studies in air pollution epidemiology may suffer from some specific forms of confounding and exposure measurement error. This contribution discusses these, mostly in the framework of cohort studies. Evaluation of potential confounding is critical in studies of the health effects of air pollution.

  14. Mismeasurement and the resonance of strong confounders: correlated errors.

    Science.gov (United States)

    Marshall, J R; Hastrup, J L; Ross, J S

    1999-07-01

    Confounding in epidemiology, and the limits of standard methods of control for an imperfectly measured confounder, have been understood for some time. However, most treatments of this problem are based on the assumption that errors of measurement in confounding and confounded variables are independent. This paper considers the situation in which a strong risk factor (confounder) and an inconsequential but suspected risk factor (confounded) are each measured with errors that are correlated; the situation appears especially likely to occur in the field of nutritional epidemiology. Error correlation appears to add little to measurement error as a source of bias in estimating the impact of a strong risk factor: it can add to, diminish, or reverse the bias induced by measurement error in estimating the impact of the inconsequential risk factor. Correlation of measurement errors can add to the difficulty involved in evaluating structures in which confounding and measurement error are present. In its presence, observed correlations among risk factors can be greater than, less than, or even opposite to the true correlations. Interpretation of multivariate epidemiologic structures in which confounding is likely requires evaluation of measurement error structures, including correlations among measurement errors.

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

    Science.gov (United States)

    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.

  16. Environmental confounding in gene-environment interaction studies.

    Science.gov (United States)

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

    2013-07-01

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

  17. Mismeasurement and the resonance of strong confounders: uncorrelated errors.

    Science.gov (United States)

    Marshall, J R; Hastrup, J L

    1996-05-15

    Greenland first documented (Am J Epidemiol 1980; 112:564-9) that error in the measurement of a confounder could resonate--that it could bias estimates of other study variables, and that the bias could persist even with statistical adjustment for the confounder as measured. An important question is raised by this finding: can such bias be more than trivial within the bounds of realistic data configurations? The authors examine several situations involving dichotomous and continuous data in which a confounder and a null variable are measured with error, and they assess the extent of resultant bias in estimates of the effect of the null variable. They show that, with continuous variables, measurement error amounting to 40% of observed variance in the confounder could cause the observed impact of the null study variable to appear to alter risk by as much as 30%. Similarly, they show, with dichotomous independent variables, that 15% measurement error in the form of misclassification could lead the null study variable to appear to alter risk by as much as 50%. Such bias would result only from strong confounding. Measurement error would obscure the evidence that strong confounding is a likely problem. These results support the need for every epidemiologic inquiry to include evaluations of measurement error in each variable considered.

  18. Confounding adjustment through front-door blocking in longitudinal studies

    Directory of Open Access Journals (Sweden)

    Arvid Sjölander

    2013-03-01

    Full Text Available A common aim of epidemiological research is to estimate the causal effect of a particular exposure on a particular outcome. Towards this end, observed associations are often ‘adjusted’ for potential confounding variables. When the potential confounders are unmeasured, explicit adjustment becomes unfeasible. It has been demonstrated that causal effects can be estimated even in the presence of umeasured confounding, utilizing a method called ‘front-door blocking’. In this paper we generalize this method to longitudinal studies. We demonstrate that the method of front-door blocking poses a number of challenging statistical problems, analogous to the famous problems associ- ated with the method of ‘back-door blocking’.

  19. CONFOUNDING STRUCTURE OF TWO-LEVEL NONREGULAR FACTORIAL DESIGNS

    Institute of Scientific and Technical Information of China (English)

    Ren Junbai

    2012-01-01

    In design theory,the alias structure of regular fractional factorial designs is elegantly described with group theory.However,this approach cannot be applied to nonregular designs directly. For an arbitrary nonregular design,a natural question is how to describe the confounding relations between its effects,is there any inner structure similar to regular designs? The aim of this article is to answer this basic question.Using coefficients of indicator function,confounding structure of nonregular fractional factorial designs is obtained as linear constrains on the values of effects.A method to estimate the sparse significant effects in an arbitrary nonregular design is given through an example.

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

    Directory of Open Access Journals (Sweden)

    Doyle Scott

    2012-10-01

    Full Text Available Abstract 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

  1. Confounding and exposure measurement error in air pollution epidemiology.

    Science.gov (United States)

    Sheppard, Lianne; Burnett, Richard T; Szpiro, Adam A; Kim, Sun-Young; Jerrett, Michael; Pope, C Arden; Brunekreef, Bert

    2012-06-01

    Studies in air pollution epidemiology may suffer from some specific forms of confounding and exposure measurement error. This contribution discusses these, mostly in the framework of cohort studies. Evaluation of potential confounding is critical in studies of the health effects of air pollution. The association between long-term exposure to ambient air pollution and mortality has been investigated using cohort studies in which subjects are followed over time with respect to their vital status. In such studies, control for individual-level confounders such as smoking is important, as is control for area-level confounders such as neighborhood socio-economic status. In addition, there may be spatial dependencies in the survival data that need to be addressed. These issues are illustrated using the American Cancer Society Cancer Prevention II cohort. Exposure measurement error is a challenge in epidemiology because inference about health effects can be incorrect when the measured or predicted exposure used in the analysis is different from the underlying true exposure. Air pollution epidemiology rarely if ever uses personal measurements of exposure for reasons of cost and feasibility. Exposure measurement error in air pollution epidemiology comes in various dominant forms, which are different for time-series and cohort studies. The challenges are reviewed and a number of suggested solutions are discussed for both study domains.

  2. Investigating the Idoho oil spillage into Lagos: Some confounding ...

    African Journals Online (AJOL)

    ... caused by these spillages must consider the socio-economic characteristics of the population as this may reveal a true picture of the event and facilitate proper interpretation of the result. Keywords: Toxicity, Idoho Oil Spillage, Confounders, Socio economic factors. Nigerian Journal of Health and Biomedical Sciences Vol.

  3. Hypnotics and mortality – confounding by disease and socioeconomic position

    DEFF Research Database (Denmark)

    Kriegbaum, Margit; Hendriksen, Carsten; Vass, Mikkel

    2015-01-01

    Purpose The aim of this Cohort study of 10 527 Danish men was to investigate the extent to which the association between hypnotics and mortality is confounded by several markers of disease and living conditions. Methods Exposure was purchases of hypnotics 1995–1999 (“low users” (150 or less defined......% confidence intervals (CI). Results When covariates were entered one at a time, the changes in HR estimates showed that psychiatric disease, socioeconomic position and substance abuse reduced the excess risk by 17–36% in the low user group and by 45–52% in the high user group. Somatic disease, intelligence...... point at psychiatric disease, substance abuse and socioeconomic position as potential confounding factors partly explaining the association between use of hypnotics and all-cause mortality....

  4. Confounding of three binary-variables counterfactual model

    OpenAIRE

    Liu, Jingwei; Hu, Shuang

    2011-01-01

    Confounding of three binary-variables counterfactual model is discussed in this paper. According to the effect between the control variable and the covariate variable, we investigate three counterfactual models: the control variable is independent of the covariate variable, the control variable has the effect on the covariate variable and the covariate variable affects the control variable. Using the ancillary information based on conditional independence hypotheses, the sufficient conditions...

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

    Directory of Open Access Journals (Sweden)

    Enrica Migliore

    Full Text Available 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.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.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.The association between maternal paracetamol use during pregnancy and infant wheezing is mainly, if not completely explained by confounding.

  6. Heterogeneity in white blood cells has potential to confound DNA methylation measurements.

    Directory of Open Access Journals (Sweden)

    Bjorn T Adalsteinsson

    Full Text Available Epigenetic studies are commonly conducted on DNA from tissue samples. However, tissues are ensembles of cells that may each have their own epigenetic profile, and therefore inter-individual cellular heterogeneity may compromise these studies. Here, we explore the potential for such confounding on DNA methylation measurement outcomes when using DNA from whole blood. DNA methylation was measured using pyrosequencing-based methodology in whole blood (n = 50-179 and in two white blood cell fractions (n = 20, isolated using density gradient centrifugation, in four CGIs (CpG Islands located in genes HHEX (10 CpG sites assayed, KCNJ11 (8 CpGs, KCNQ1 (4 CpGs and PM20D1 (7 CpGs. Cellular heterogeneity (variation in proportional white blood cell counts of neutrophils, lymphocytes, monocytes, eosinophils and basophils, counted by an automated cell counter explained up to 40% (p<0.0001 of the inter-individual variation in whole blood DNA methylation levels in the HHEX CGI, but not a significant proportion of the variation in the other three CGIs tested. DNA methylation levels in the two cell fractions, polymorphonuclear and mononuclear cells, differed significantly in the HHEX CGI; specifically the average absolute difference ranged between 3.4-15.7 percentage points per CpG site. In the other three CGIs tested, methylation levels in the two fractions did not differ significantly, and/or the difference was more moderate. In the examined CGIs, methylation levels were highly correlated between cell fractions. In summary, our analysis detects region-specific differential DNA methylation between white blood cell subtypes, which can confound the outcome of whole blood DNA methylation measurements. Finally, by demonstrating the high correlation between methylation levels in cell fractions, our results suggest a possibility to use a proportional number of a single white blood cell type to correct for this confounding effect in analyses.

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

    Directory of Open Access Journals (Sweden)

    Anne-Christin Hauschild

    2015-06-01

    Full Text Available 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

  8. Assessment of Confounding in Studies of Delay and Survival

    DEFF Research Database (Denmark)

    Tørring, Marie Louise; Vedsted, Peter; Frydenberg, Morten

    BACKGROUND: Whether longer time to diagnosis (diagnostic delay) in patients with cancer symptoms is directly and independently associated with poor prognosis cannot be determined in randomised controlled trials. Analysis of observational data is therefore necessary. Many previous studies of the i......BACKGROUND: Whether longer time to diagnosis (diagnostic delay) in patients with cancer symptoms is directly and independently associated with poor prognosis cannot be determined in randomised controlled trials. Analysis of observational data is therefore necessary. Many previous studies......) Clarify which factors are considered confounders or intermediate variables in the literature. 2) Assess how and to what extent these factors bias survival estimates. CONSIDERATIONS: As illustrated in Figure 1, symptoms of cancer may alert patients, GP's, and hospital doctors differently and influence both...... delay and survival time in different ways. We therefore assume that the impact of confounding factors depends on the type of delay studied (e.g., patient delay, GP delay, referral delay, or treatment delay). MATERIALS & METHODS: The project includes systematic review and methodological developments...

  9. Negative confounding by essential fatty acids in methylmercury neurotoxicity associations

    DEFF Research Database (Denmark)

    Choi, Anna L; Mogensen, Ulla Brasch; Bjerve, Kristian S

    2014-01-01

    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...... 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...

  10. phMRI: methodological considerations for mitigating potential confounding factors

    Directory of Open Access Journals (Sweden)

    Julius H Bourke

    2015-05-01

    Full Text Available 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.

  11. Multisample adjusted U-statistics that account for confounding covariates.

    Science.gov (United States)

    Satten, Glen A; Kong, Maiying; Datta, Somnath

    2018-06-19

    Multisample U-statistics encompass a wide class of test statistics that allow the comparison of 2 or more distributions. U-statistics are especially powerful because they can be applied to both numeric and nonnumeric data, eg, ordinal and categorical data where a pairwise similarity or distance-like measure between categories is available. However, when comparing the distribution of a variable across 2 or more groups, observed differences may be due to confounding covariates. For example, in a case-control study, the distribution of exposure in cases may differ from that in controls entirely because of variables that are related to both exposure and case status and are distributed differently among case and control participants. We propose to use individually reweighted data (ie, using the stratification score for retrospective data or the propensity score for prospective data) to construct adjusted U-statistics that can test the equality of distributions across 2 (or more) groups in the presence of confounding covariates. Asymptotic normality of our adjusted U-statistics is established and a closed form expression of their asymptotic variance is presented. The utility of our approach is demonstrated through simulation studies, as well as in an analysis of data from a case-control study conducted among African-Americans, comparing whether the similarity in haplotypes (ie, sets of adjacent genetic loci inherited from the same parent) occurring in a case and a control participant differs from the similarity in haplotypes occurring in 2 control participants. Copyright © 2018 John Wiley & Sons, Ltd.

  12. Determining Confounding Sensitivities In Eddy Current Thin Film Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Gros, Ethan; Udpa, Lalita; Smith, James A.; Wachs, Katelyn

    2016-07-01

    Determining Confounding Sensitivities In Eddy Current Thin Film Measurements Ethan Gros, Lalita Udpa, Electrical Engineering, Michigan State University, East Lansing MI 48824 James A. Smith, Experiment Analysis, Idaho National Laboratory, Idaho Falls ID 83415 Eddy current (EC) techniques are widely used in industry to measure the thickness of non-conductive films on a metal substrate. This is done using a system whereby a coil carrying a high-frequency alternating current is used to create an alternating magnetic field at the surface of the instrument's probe. When the probe is brought near a conductive surface, the alternating magnetic field will induce ECs in the conductor. The substrate characteristics and the distance of the probe from the substrate (the coating thickness) affect the magnitude of the ECs. The induced currents load the probe coil affecting the terminal impedance of the coil. The measured probe impedance is related to the lift off between coil and conductor as well as conductivity of the test sample. For a known conductivity sample, the probe impedance can be converted into an equivalent film thickness value. The EC measurement can be confounded by a number of measurement parameters. It is the goal of this research to determine which physical properties of the measurement set-up and sample can adversely affect the thickness measurement. The eddy current testing is performed using a commercially available, hand held eddy current probe (ETA3.3H spring loaded eddy probe running at 8 MHz) that comes with a stand to hold the probe. The stand holds the probe and adjusts the probe on the z-axis to help position the probe in the correct area as well as make precise measurements. The signal from the probe is sent to a hand held readout, where the results are recorded directly in terms of liftoff or film thickness. Understanding the effect of certain factors on the measurements of film thickness, will help to evaluate how accurate the ETA3.3H spring

  13. Estimation of inspection effort

    International Nuclear Information System (INIS)

    Mullen, M.F.; Wincek, M.A.

    1979-06-01

    An overview of IAEA inspection activities is presented, and the problem of evaluating the effectiveness of an inspection is discussed. Two models are described - an effort model and an effectiveness model. The effort model breaks the IAEA's inspection effort into components; the amount of effort required for each component is estimated; and the total effort is determined by summing the effort for each component. The effectiveness model quantifies the effectiveness of inspections in terms of probabilities of detection and quantities of material to be detected, if diverted over a specific period. The method is applied to a 200 metric ton per year low-enriched uranium fuel fabrication facility. A description of the model plant is presented, a safeguards approach is outlined, and sampling plans are calculated. The required inspection effort is estimated and the results are compared to IAEA estimates. Some other applications of the method are discussed briefly. Examples are presented which demonstrate how the method might be useful in formulating guidelines for inspection planning and in establishing technical criteria for safeguards implementation

  14. Handling stress may confound murine gut microbiota studies

    Directory of Open Access Journals (Sweden)

    Cary R. Allen-Blevins

    2017-01-01

    Full Text Available Background Accumulating evidence indicates interactions between human milk composition, particularly sugars (human milk oligosaccharides or HMO, the gut microbiota of human infants, and behavioral effects. Some HMO secreted in human milk are unable to be endogenously digested by the human infant but are able to be metabolized by certain species of gut microbiota, including Bifidobacterium longum subsp. infantis (B. infantis, a species sensitive to host stress (Bailey & Coe, 2004. Exposure to gut bacteria like B. infantisduring critical neurodevelopment windows in early life appears to have behavioral consequences; however, environmental, physical, and social stress during this period can also have behavioral and microbial consequences. While rodent models are a useful method for determining causal relationships between HMO, gut microbiota, and behavior, murine studies of gut microbiota usually employ oral gavage, a technique stressful to the mouse. Our aim was to develop a less-invasive technique for HMO administration to remove the potential confound of gavage stress. Under the hypothesis that stress affects gut microbiota, particularly B. infantis, we predicted the pups receiving a prebiotic solution in a less-invasive manner would have the highest amount of Bifidobacteria in their gut. Methods This study was designed to test two methods, active and passive, of solution administration to mice and the effects on their gut microbiome. Neonatal C57BL/6J mice housed in a specific-pathogen free facility received increasing doses of fructooligosaccharide (FOS solution or deionized, distilled water. Gastrointestinal (GI tracts were collected from five dams, six sires, and 41 pups over four time points. Seven fecal pellets from unhandled pups and two pellets from unhandled dams were also collected. Qualitative real-time polymerase chain reaction (qRT-PCR was used to quantify and compare the amount of Bifidobacterium, Bacteroides, Bacteroidetes, and

  15. Examining the role of unmeasured confounding in mediation analysis with genetic and genomic applications.

    Science.gov (United States)

    Lutz, Sharon M; Thwing, Annie; Schmiege, Sarah; Kroehl, Miranda; Baker, Christopher D; Starling, Anne P; Hokanson, John E; Ghosh, Debashis

    2017-07-19

    In mediation analysis if unmeasured confounding is present, the estimates for the direct and mediated effects may be over or under estimated. Most methods for the sensitivity analysis of unmeasured confounding in mediation have focused on the mediator-outcome relationship. The Umediation R package enables the user to simulate unmeasured confounding of the exposure-mediator, exposure-outcome, and mediator-outcome relationships in order to see how the results of the mediation analysis would change in the presence of unmeasured confounding. We apply the Umediation package to the Genetic Epidemiology of Chronic Obstructive Pulmonary Disease (COPDGene) study to examine the role of unmeasured confounding due to population stratification on the effect of a single nucleotide polymorphism (SNP) in the CHRNA5/3/B4 locus on pulmonary function decline as mediated by cigarette smoking. Umediation is a flexible R package that examines the role of unmeasured confounding in mediation analysis allowing for normally distributed or Bernoulli distributed exposures, outcomes, mediators, measured confounders, and unmeasured confounders. Umediation also accommodates multiple measured confounders, multiple unmeasured confounders, and allows for a mediator-exposure interaction on the outcome. Umediation is available as an R package at https://github.com/SharonLutz/Umediation A tutorial on how to install and use the Umediation package is available in the Additional file 1.

  16. Assessing mediation using marginal structural models in the presence of confounding and moderation

    OpenAIRE

    Coffman, Donna L.; Zhong, Wei

    2012-01-01

    This paper presents marginal structural models (MSMs) with inverse propensity weighting (IPW) for assessing mediation. Generally, individuals are not randomly assigned to levels of the mediator. Therefore, confounders of the mediator and outcome may exist that limit causal inferences, a goal of mediation analysis. Either regression adjustment or IPW can be used to take confounding into account, but IPW has several advantages. Regression adjustment of even one confounder of the mediator and ou...

  17. Directed acyclic graphs (DAGs): an aid to assess confounding in dental research.

    Science.gov (United States)

    Merchant, Anwar T; Pitiphat, Waranuch

    2002-12-01

    Confounding, a special type of bias, occurs when an extraneous factor is associated with the exposure and independently affects the outcome. In order to get an unbiased estimate of the exposure-outcome relationship, we need to identify potential confounders, collect information on them, design appropriate studies, and adjust for confounding in data analysis. However, it is not always clear which variables to collect information on and adjust for in the analyses. Inappropriate adjustment for confounding can even introduce bias where none existed. Directed acyclic graphs (DAGs) provide a method to select potential confounders and minimize bias in the design and analysis of epidemiological studies. DAGs have been used extensively in expert systems and robotics. Robins (1987) introduced the application of DAGs in epidemiology to overcome shortcomings of traditional methods to control for confounding, especially as they related to unmeasured confounding. DAGs provide a quick and visual way to assess confounding without making parametric assumptions. We introduce DAGs, starting with definitions and rules for basic manipulation, stressing more on applications than theory. We then demonstrate their application in the control of confounding through examples of observational and cross-sectional epidemiological studies.

  18. Poppers, Kaposi's sarcoma, and HIV infection: empirical example of a strong confounding effect?

    Science.gov (United States)

    Morabia, A

    1995-01-01

    Are there empirical examples of strong confounding effects? Textbooks usually show examples of weak confounding or use hypothetical examples of strong confounding to illustrate the paradoxical consequences of not separating out the effect of the studied exposure from that of second factor acting as a confounder. HIV infection is a candidate strong confounder of the spuriously high association reported between consumption of poppers, a sexual stimulant, and risk of Kaposi's sarcoma in the early phase of the AIDS epidemic. To examine this hypothesis, assumptions must be made on the prevalence of HIV infection among cases of Kaposi's sarcoma and on the prevalence of heavy popper consumption according to HIV infection in cases and controls. Results show that HIV infection may have confounded the poppers-Kaposi's sarcoma association. However, it cannot be ruled out that HIV did not qualify as a confounder because it was either an intermediate variable or an effect modifier of the association between popper inhalation and Kaposi's sarcoma. This example provides a basis to discuss the mechanism by which confounding occurs as well as the practical importance of confounding in epidemiologic research.

  19. Confounder selection in environmental epidemiology: Assessment of health effects of prenatal mercury exposure

    DEFF Research Database (Denmark)

    Budtz-Jørgensen, Esben; Keiding, Niels; Grandjean, Philippe

    2007-01-01

    PURPOSE: The purpose of the study is to compare different approaches to the identification of confounders needed for analyzing observational data. Whereas standard analysis usually is conducted as if the confounders were known a priori, selection uncertainty also must be taken into account. METHO...

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

    Science.gov (United States)

    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 ...

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

    Science.gov (United States)

    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 ...

  2. Quantitative assessment of unobserved confounding is mandatory in nonrandomized intervention studies

    NARCIS (Netherlands)

    Groenwold, R H H; Hak, E; Hoes, A W

    OBJECTIVE: In nonrandomized intervention studies unequal distribution of patient characteristics in the groups under study may hinder comparability of prognosis and therefore lead to confounding bias. Our objective was to review methods to control for observed confounding, as well as unobserved

  3. Literality and Cognitive Effort

    DEFF Research Database (Denmark)

    Lacruz, Isabel; Carl, Michael; Yamada, Masaru

    2018-01-01

    We introduce a notion of pause-word ratio computed using ranges of pause lengths rather than lower cutoffs for pause lengths. Standard pause-word ratios are indicators of cognitive effort during different translation modalities.The pause range version allows for the study of how different types...... remoteness. We use data from the CRITT TPR database, comparing translation and post-editing from English to Japanese and from English to Spanish, and study the interaction of pause-word ratio for short pauses ranging between 300 and 500ms with syntactic remoteness, measured by the CrossS feature, semantic...... remoteness, measured by HTra, and syntactic and semantic remoteness, measured by Literality....

  4. Breckinridge Project, initial effort

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    1982-09-01

    Report III, Volume 1 contains those specifications numbered A through J, as follows: General Specifications (A); Specifications for Pressure Vessels (C); Specifications for Tanks (D); Specifications for Exchangers (E); Specifications for Fired Heaters (F); Specifications for Pumps and Drivers (G); and Specifications for Instrumentation (J). The standard specifications of Bechtel Petroleum Incorporated have been amended as necessary to reflect the specific requirements of the Breckinridge Project, and the more stringent specifications of Ashland Synthetic Fuels, Inc. These standard specifications are available to the Initial Effort (Phase Zero) work performed by all contractors and subcontractors. Report III, Volume 1 also contains the unique specifications prepared for Plants 8, 15, and 27. These specifications will be substantially reviewed during Phase I of the project, and modified as necessary for use during the engineering, procurement, and construction of this project.

  5. Mapping telemedicine efforts

    DEFF Research Database (Denmark)

    Kierkegaard, Patrick

    2015-01-01

    are being utilized? What medical disciplines are being addressed using telemedicine systems? Methods: All data was surveyed from the "Telemedicinsk Landkort", a newly created database designed to provide a comprehensive and systematic overview of all telemedicine technologies in Denmark. Results......Objectives: The aim of this study is to survey telemedicine services currently in operation across Denmark. The study specifically seeks to answer the following questions: What initiatives are deployed within the different regions? What are the motivations behind the projects? What technologies......: The results of this study suggest that a growing number of telemedicine initiatives are currently in operation across Denmark but that considerable variations existed in terms of regional efforts as the number of operational telemedicine projects varied from region to region. Conclusions: The results...

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

    Science.gov (United States)

    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. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Quantifying the potential role of unmeasured confounders : the example of influenza vaccination

    NARCIS (Netherlands)

    Groenwold, R H H; Hoes, A W; Nichol, K L; Hak, E

    2008-01-01

    BACKGROUND: The validity of non-randomized studies using healthcare databases is often challenged because they lack information on potentially important confounders, such as functional health status and socioeconomic status. In a study quantifying the effects of influenza vaccination among

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

    DEFF Research Database (Denmark)

    Bulik-Sullivan, Brendan K.; Loh, Po-Ru; Finucane, Hilary K.

    2015-01-01

    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...

  9. Confounding in statistical mediation analysis: What it is and how to address it.

    Science.gov (United States)

    Valente, Matthew J; Pelham, William E; Smyth, Heather; MacKinnon, David P

    2017-11-01

    Psychology researchers are often interested in mechanisms underlying how randomized interventions affect outcomes such as substance use and mental health. Mediation analysis is a common statistical method for investigating psychological mechanisms that has benefited from exciting new methodological improvements over the last 2 decades. One of the most important new developments is methodology for estimating causal mediated effects using the potential outcomes framework for causal inference. Potential outcomes-based methods developed in epidemiology and statistics have important implications for understanding psychological mechanisms. We aim to provide a concise introduction to and illustration of these new methods and emphasize the importance of confounder adjustment. First, we review the traditional regression approach for estimating mediated effects. Second, we describe the potential outcomes framework. Third, we define what a confounder is and how the presence of a confounder can provide misleading evidence regarding mechanisms of interventions. Fourth, we describe experimental designs that can help rule out confounder bias. Fifth, we describe new statistical approaches to adjust for measured confounders of the mediator-outcome relation and sensitivity analyses to probe effects of unmeasured confounders on the mediated effect. All approaches are illustrated with application to a real counseling intervention dataset. Counseling psychologists interested in understanding the causal mechanisms of their interventions can benefit from incorporating the most up-to-date techniques into their mediation analyses. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  10. Cardiovascular health, traffic-related air pollution and noise: are associations mutually confounded? A systematic review.

    Science.gov (United States)

    Tétreault, Louis-François; Perron, Stéphane; Smargiassi, Audrey

    2013-10-01

    This review assessed the confounding effect of one traffic-related exposure (noise or air pollutants) on the association between the other exposure and cardiovascular outcomes. A systematic review was conducted with the databases Medline and Embase. The confounding effects in studies were assessed by using change in the estimate with a 10 % cutoff point. The influence on the change in the estimate of the quality of the studies, the exposure assessment methods and the correlation between road noise and air pollutions were also assessed. Nine publications were identified. For most studies, the specified confounders produced changes in estimates noise and pollutants, the quality of the study and of the exposure assessment do not seem to influence the confounding effects. Results from this review suggest that confounding of cardiovascular effects by noise or air pollutants is low, though with further improvements in exposure assessment, the situation may change. More studies using pollution indicators specific to road traffic are needed to properly assess if noise and air pollution are subjected to confounding.

  11. Risk of bias and confounding of observational studies of Zika virus infection: A scoping review of research protocols.

    Science.gov (United States)

    Reveiz, Ludovic; Haby, Michelle M; Martínez-Vega, Ruth; Pinzón-Flores, Carlos E; Elias, Vanessa; Smith, Emma; Pinart, Mariona; Broutet, Nathalie; Becerra-Posada, Francisco; Aldighieri, Sylvain; Van Kerkhove, Maria D

    2017-01-01

    Given the severity and impact of the current Zika virus (ZIKV) outbreak in the Americas, numerous countries have rushed to develop research studies to assess ZIKV and its potential health consequences. In an effort to ensure that studies are comprehensive, both internally and externally valid, and with reliable results, the World Health Organization, the Pan American Health Organization, Institut Pasteur, the networks of Fiocruz, the Consortia for the Standardization of Influenza Seroepidemiology (CONSISE) and the International Severe Acute Respiratory and Emerging Infection Consortium (ISARIC) have generated six standardized clinical and epidemiological research protocols and questionnaires to address key public health questions on ZIKV. We conducted a systematic search of ongoing study protocols related to ZIKV research. We analyzed the content of protocols of 32 cohort studies and 13 case control studies for systematic bias that could produce erroneous results. Additionally we aimed to characterize the risks of bias and confounding in observational studies related to ZIKV and to propose ways to minimize them, including the use of six newly standardized research protocols. Observational studies of ZIKV face an array of challenges, including measurement of exposure and outcomes (microcephaly and Guillain-Barré Syndrome). Potential confounders need to be measured where known and controlled for in the analysis. Selection bias due to non-random selection is a significant issue, particularly in the case-control design, and losses to follow-up is equally important for the cohort design. Observational research seeking to answer key questions on the ZIKV should consider these restrictions and take precautions to minimize bias in an effort to provide reliable and valid results. Utilization of the standardized research protocols developed by the WHO, PAHO, Institut Pasteur, and CONSISE will harmonize the key methodological aspects of each study design to minimize bias at

  12. Risk of bias and confounding of observational studies of Zika virus infection: A scoping review of research protocols.

    Directory of Open Access Journals (Sweden)

    Ludovic Reveiz

    Full Text Available Given the severity and impact of the current Zika virus (ZIKV outbreak in the Americas, numerous countries have rushed to develop research studies to assess ZIKV and its potential health consequences. In an effort to ensure that studies are comprehensive, both internally and externally valid, and with reliable results, the World Health Organization, the Pan American Health Organization, Institut Pasteur, the networks of Fiocruz, the Consortia for the Standardization of Influenza Seroepidemiology (CONSISE and the International Severe Acute Respiratory and Emerging Infection Consortium (ISARIC have generated six standardized clinical and epidemiological research protocols and questionnaires to address key public health questions on ZIKV.We conducted a systematic search of ongoing study protocols related to ZIKV research. We analyzed the content of protocols of 32 cohort studies and 13 case control studies for systematic bias that could produce erroneous results. Additionally we aimed to characterize the risks of bias and confounding in observational studies related to ZIKV and to propose ways to minimize them, including the use of six newly standardized research protocols.Observational studies of ZIKV face an array of challenges, including measurement of exposure and outcomes (microcephaly and Guillain-Barré Syndrome. Potential confounders need to be measured where known and controlled for in the analysis. Selection bias due to non-random selection is a significant issue, particularly in the case-control design, and losses to follow-up is equally important for the cohort design.Observational research seeking to answer key questions on the ZIKV should consider these restrictions and take precautions to minimize bias in an effort to provide reliable and valid results. Utilization of the standardized research protocols developed by the WHO, PAHO, Institut Pasteur, and CONSISE will harmonize the key methodological aspects of each study design to

  13. Swedish nuclear waste efforts

    International Nuclear Information System (INIS)

    Rydberg, J.

    1981-09-01

    After the introduction of a law prohibiting the start-up of any new nuclear power plant until the utility had shown that the waste produced by the plant could be taken care of in an absolutely safe way, the Swedish nuclear utilities in December 1976 embarked on the Nuclear Fuel Safety Project, which in November 1977 presented a first report, Handling of Spent Nuclear Fuel and Final Storage of Vitrified Waste (KBS-I), and in November 1978 a second report, Handling and Final Storage of Unreprocessed Spent Nuclear Fuel (KBS II). These summary reports were supported by 120 technical reports prepared by 450 experts. The project engaged 70 private and governmental institutions at a total cost of US $15 million. The KBS-I and KBS-II reports are summarized in this document, as are also continued waste research efforts carried out by KBS, SKBF, PRAV, ASEA and other Swedish organizations. The KBS reports describe all steps (except reprocessing) in handling chain from removal from a reactor of spent fuel elements until their radioactive waste products are finally disposed of, in canisters, in an underground granite depository. The KBS concept relies on engineered multibarrier systems in combination with final storage in thoroughly investigated stable geologic formations. This report also briefly describes other activities carried out by the nuclear industry, namely, the construction of a central storage facility for spent fuel elements (to be in operation by 1985), a repository for reactor waste (to be in operation by 1988), and an intermediate storage facility for vitrified high-level waste (to be in operation by 1990). The R and D activities are updated to September 1981

  14. Worldwide effort against smoking.

    Science.gov (United States)

    1986-07-01

    The 39th World Health Assembly, which met in May 1986, recognized the escalating health problem of smoking-related diseases and affirmed that tobacco smoking and its use in other forms are incompatible with the attainment of "Health for All by the Year 2000." If properly implemented, antismoking campaigns can decrease the prevalence of smoking. Nations as a whole must work toward changing smoking habits, and governments must support these efforts by officially stating their stand against smoking. Over 60 countries have introduced legislation affecting smoking. The variety of policies range from adopting a health education program designed to increase peoples' awareness of its dangers to increasing taxes to deter smoking by increasing tobacco prices. Each country must adopt an antismoking campaign which works most effectively within the cultural parameters of the society. Other smoking policies include: printed warnings on cigarette packages; health messages via radio, television, mobile teams, pamphlets, health workers, clinic walls, and newspapers; prohibition of smoking in public areas and transportation; prohibition of all advertisement of cigarettes and tobacco; and the establishment of upper limits of tar and nicotine content in cigarettes. The tobacco industry spends about $2000 million annually on worldwide advertising. According to the World Health Organization (WHO), controlling this overabundance of tobacco advertisements is a major priority in preventing the spread of smoking. Cigarette and tobacco advertising can be controlled to varying degrees, e.g., over a dozen countries have enacted a total ban on advertising on television or radio, a mandatory health warning must accompany advertisements in other countries, and tobacco companies often are prohibited from sponsoring sports events. Imposing a substantial tax on cigarettes is one of the most effective means to deter smoking. However, raising taxes and banning advertisements is not enough because

  15. The Effort Paradox: Effort Is Both Costly and Valued.

    Science.gov (United States)

    Inzlicht, Michael; Shenhav, Amitai; Olivola, Christopher Y

    2018-04-01

    According to prominent models in cognitive psychology, neuroscience, and economics, effort (be it physical or mental) is costly: when given a choice, humans and non-human animals alike tend to avoid effort. Here, we suggest that the opposite is also true and review extensive evidence that effort can also add value. Not only can the same outcomes be more rewarding if we apply more (not less) effort, sometimes we select options precisely because they require effort. Given the increasing recognition of effort's role in motivation, cognitive control, and value-based decision-making, considering this neglected side of effort will not only improve formal computational models, but also provide clues about how to promote sustained mental effort across time. Copyright © 2018 Elsevier Ltd. All rights reserved.

  16. The alarming problems of confounding equivalence using logistic regression models in the perspective of causal diagrams

    Directory of Open Access Journals (Sweden)

    Yuanyuan Yu

    2017-12-01

    Full Text Available Abstract Background Confounders can produce spurious associations between exposure and outcome in observational studies. For majority of epidemiologists, adjusting for confounders using logistic regression model is their habitual method, though it has some problems in accuracy and precision. It is, therefore, important to highlight the problems of logistic regression and search the alternative method. Methods Four causal diagram models were defined to summarize confounding equivalence. Both theoretical proofs and simulation studies were performed to verify whether conditioning on different confounding equivalence sets had the same bias-reducing potential and then to select the optimum adjusting strategy, in which logistic regression model and inverse probability weighting based marginal structural model (IPW-based-MSM were compared. The “do-calculus” was used to calculate the true causal effect of exposure on outcome, then the bias and standard error were used to evaluate the performances of different strategies. Results Adjusting for different sets of confounding equivalence, as judged by identical Markov boundaries, produced different bias-reducing potential in the logistic regression model. For the sets satisfied G-admissibility, adjusting for the set including all the confounders reduced the equivalent bias to the one containing the parent nodes of the outcome, while the bias after adjusting for the parent nodes of exposure was not equivalent to them. In addition, all causal effect estimations through logistic regression were biased, although the estimation after adjusting for the parent nodes of exposure was nearest to the true causal effect. However, conditioning on different confounding equivalence sets had the same bias-reducing potential under IPW-based-MSM. Compared with logistic regression, the IPW-based-MSM could obtain unbiased causal effect estimation when the adjusted confounders satisfied G-admissibility and the optimal

  17. The alarming problems of confounding equivalence using logistic regression models in the perspective of causal diagrams.

    Science.gov (United States)

    Yu, Yuanyuan; Li, Hongkai; Sun, Xiaoru; Su, Ping; Wang, Tingting; Liu, Yi; Yuan, Zhongshang; Liu, Yanxun; Xue, Fuzhong

    2017-12-28

    Confounders can produce spurious associations between exposure and outcome in observational studies. For majority of epidemiologists, adjusting for confounders using logistic regression model is their habitual method, though it has some problems in accuracy and precision. It is, therefore, important to highlight the problems of logistic regression and search the alternative method. Four causal diagram models were defined to summarize confounding equivalence. Both theoretical proofs and simulation studies were performed to verify whether conditioning on different confounding equivalence sets had the same bias-reducing potential and then to select the optimum adjusting strategy, in which logistic regression model and inverse probability weighting based marginal structural model (IPW-based-MSM) were compared. The "do-calculus" was used to calculate the true causal effect of exposure on outcome, then the bias and standard error were used to evaluate the performances of different strategies. Adjusting for different sets of confounding equivalence, as judged by identical Markov boundaries, produced different bias-reducing potential in the logistic regression model. For the sets satisfied G-admissibility, adjusting for the set including all the confounders reduced the equivalent bias to the one containing the parent nodes of the outcome, while the bias after adjusting for the parent nodes of exposure was not equivalent to them. In addition, all causal effect estimations through logistic regression were biased, although the estimation after adjusting for the parent nodes of exposure was nearest to the true causal effect. However, conditioning on different confounding equivalence sets had the same bias-reducing potential under IPW-based-MSM. Compared with logistic regression, the IPW-based-MSM could obtain unbiased causal effect estimation when the adjusted confounders satisfied G-admissibility and the optimal strategy was to adjust for the parent nodes of outcome, which

  18. Bias, Confounding, and Interaction: Lions and Tigers, and Bears, Oh My!

    Science.gov (United States)

    Vetter, Thomas R; Mascha, Edward J

    2017-09-01

    Epidemiologists seek to make a valid inference about the causal effect between an exposure and a disease in a specific population, using representative sample data from a specific population. Clinical researchers likewise seek to make a valid inference about the association between an intervention and outcome(s) in a specific population, based upon their randomly collected, representative sample data. Both do so by using the available data about the sample variable to make a valid estimate about its corresponding or underlying, but unknown population parameter. Random error in an experiment can be due to the natural, periodic fluctuation or variation in the accuracy or precision of virtually any data sampling technique or health measurement tool or scale. In a clinical research study, random error can be due to not only innate human variability but also purely chance. Systematic error in an experiment arises from an innate flaw in the data sampling technique or measurement instrument. In the clinical research setting, systematic error is more commonly referred to as systematic bias. The most commonly encountered types of bias in anesthesia, perioperative, critical care, and pain medicine research include recall bias, observational bias (Hawthorne effect), attrition bias, misclassification or informational bias, and selection bias. A confounding variable is a factor associated with both the exposure of interest and the outcome of interest. A confounding variable (confounding factor or confounder) is a variable that correlates (positively or negatively) with both the exposure and outcome. Confounding is typically not an issue in a randomized trial because the randomized groups are sufficiently balanced on all potential confounding variables, both observed and nonobserved. However, confounding can be a major problem with any observational (nonrandomized) study. Ignoring confounding in an observational study will often result in a "distorted" or incorrect estimate of

  19. Propensity score methodology for confounding control in health care utilization databases

    Directory of Open Access Journals (Sweden)

    Elisabetta Patorno

    2013-06-01

    Full Text Available Propensity score (PS methodology is a common approach to control for confounding in nonexperimental studies of treatment effects using health care utilization databases. This methodology offers researchers many advantages compared with conventional multivariate models: it directly focuses on the determinants of treatment choice, facilitating the understanding of the clinical decision-making process by the researcher; it allows for graphical comparisons of the distribution of propensity scores and truncation of subjects without overlapping PS indicating a lack of equipoise; it allows transparent assessment of the confounder balance achieved by the PS at baseline; and it offers a straightforward approach to reduce the dimensionality of sometimes large arrays of potential confounders in utilization databases, directly addressing the “curse of dimensionality” in the context of rare events. This article provides an overview of the use of propensity score methodology for pharmacoepidemiologic research with large health care utilization databases, covering recent discussions on covariate selection, the role of automated techniques for addressing unmeasurable confounding via proxies, strategies to maximize clinical equipoise at baseline, and the potential of machine-learning algorithms for optimized propensity score estimation. The appendix discusses the available software packages for PS methodology. Propensity scores are a frequently used and versatile tool for transparent and comprehensive adjustment of confounding in pharmacoepidemiology with large health care databases.

  20. The performance of random coefficient regression in accounting for residual confounding.

    Science.gov (United States)

    Gustafson, Paul; Greenland, Sander

    2006-09-01

    Greenland (2000, Biometrics 56, 915-921) describes the use of random coefficient regression to adjust for residual confounding in a particular setting. We examine this setting further, giving theoretical and empirical results concerning the frequentist and Bayesian performance of random coefficient regression. Particularly, we compare estimators based on this adjustment for residual confounding to estimators based on the assumption of no residual confounding. This devolves to comparing an estimator from a nonidentified but more realistic model to an estimator from a less realistic but identified model. The approach described by Gustafson (2005, Statistical Science 20, 111-140) is used to quantify the performance of a Bayesian estimator arising from a nonidentified model. From both theoretical calculations and simulations we find support for the idea that superior performance can be obtained by replacing unrealistic identifying constraints with priors that allow modest departures from those constraints. In terms of point-estimator bias this superiority arises when the extent of residual confounding is substantial, but the advantage is much broader in terms of interval estimation. The benefit from modeling residual confounding is maintained when the prior distributions employed only roughly correspond to reality, for the standard identifying constraints are equivalent to priors that typically correspond much worse.

  1. Comparison of statistical approaches dealing with time-dependent confounding in drug effectiveness studies.

    Science.gov (United States)

    Karim, Mohammad Ehsanul; Petkau, John; Gustafson, Paul; Platt, Robert W; Tremlett, Helen

    2018-06-01

    In longitudinal studies, if the time-dependent covariates are affected by the past treatment, time-dependent confounding may be present. For a time-to-event response, marginal structural Cox models are frequently used to deal with such confounding. To avoid some of the problems of fitting marginal structural Cox model, the sequential Cox approach has been suggested as an alternative. Although the estimation mechanisms are different, both approaches claim to estimate the causal effect of treatment by appropriately adjusting for time-dependent confounding. We carry out simulation studies to assess the suitability of the sequential Cox approach for analyzing time-to-event data in the presence of a time-dependent covariate that may or may not be a time-dependent confounder. Results from these simulations revealed that the sequential Cox approach is not as effective as marginal structural Cox model in addressing the time-dependent confounding. The sequential Cox approach was also found to be inadequate in the presence of a time-dependent covariate. We propose a modified version of the sequential Cox approach that correctly estimates the treatment effect in both of the above scenarios. All approaches are applied to investigate the impact of beta-interferon treatment in delaying disability progression in the British Columbia Multiple Sclerosis cohort (1995-2008).

  2. Chasing the effects of Pre-analytical Confounders - a Multicentre Study on CSF-AD biomarkers

    Directory of Open Access Journals (Sweden)

    Maria Joao Leitao

    2015-07-01

    Full Text Available Core cerebrospinal fluid (CSF biomarkers-Aβ42, Tau and pTau–have been recently incorporated in the revised criteria for Alzheimer’s disease (AD. However, their widespread clinical application lacks standardization. Pre-analytical sample handling and storage play an important role in the reliable measurement of these biomarkers across laboratories. In this study, we aim to surpass the efforts from previous studies, by employing a multicentre approach to assess the impact of less studied CSF pre-analytical confounders in AD-biomarkers quantification. Four different centres participated in this study and followed the same established protocol. CSF samples were analysed for three biomarkers (Aβ42, Tau and pTau and tested for different spinning conditions (temperature: Room temperature (RT vs. 4oC; speed: 500g vs. 2000g vs. 3000g, storage volume variations (25%, 50% and 75% of tube total volume as well as freezing-thaw cycles (up to 5 cyles. The influence of sample routine parameters, inter-centre variability and relative value of each biomarker (reported as normal/abnormal, was analysed. Centrifugation conditions did not influence biomarkers levels, except for samples with a high CSF total protein content, where either non centrifugation or centrifugation at RT, compared to 4ºC, led to higher Aβ42 levels. Reducing CSF storage volume from 75% to 50% of total tube capacity, decreased Aβ42 concentration (within analytical CV of the assay, whereas no change in Tau or pTau was observed. Moreover, the concentration of Tau and pTau appears to be stable up to 5 freeze-thaw cycles, whereas Aβ42 levels decrease if CSF is freeze-thawed more than 3 times. This systematic study reinforces the need for CSF centrifugation at 4ºC prior to storage and highlights the influence of storage conditions in Aβ42 levels. This study contributes to the establishment of harmonized standard operating procedures that will help reducing inter-lab variability of CSF

  3. Control principles of confounders in ecological comparative studies: standardization and regressive modelss

    Directory of Open Access Journals (Sweden)

    Varaksin Anatoly

    2014-03-01

    Full Text Available The methods of the analysis of research data including the concomitant variables (confounders associated with both the response and the current factor are considered. There are two usual ways to take into account such variables: the first, at the stage of planning the experiment and the second, in analyzing the received data. Despite the equal effectiveness of these approaches, there exists strong reason to restrict the usage of regression method to accounting for confounders by ANCOVA. Authors consider the standardization by stratification as a reliable method to account for the effect of confounding factors as opposed to the widely-implemented application of logistic regression and the covariance analysis. The program for the automation of standardization procedure is proposed, it is available at the site of the Institute of Industrial Ecology.

  4. Tumor hypoxia - A confounding or exploitable factor in interstitial brachytherapy? Effects of tissue trauma in an experimental rat tumor model

    NARCIS (Netherlands)

    van den Berg, AP; van Geel, CAJF; van Hooije, CMC; van der Kleij, AJ; Visser, AG

    2000-01-01

    Purpose: To evaluate the potential effects of tumor hypoxia induced by afterloading catheter implantation on the effectiveness of brachytherapy in a rat tumor model. Methods and Materials: Afterloading catheters (4) Here implanted in subcutaneously growing R1M rhabdomyosarcoma in female Wag/Rij

  5. An Introduction to Sensitivity Analysis for Unobserved Confounding in Non-Experimental Prevention Research

    Science.gov (United States)

    Kuramoto, S. Janet; Stuart, Elizabeth A.

    2013-01-01

    Despite that randomization is the gold standard for estimating causal relationships, many questions in prevention science are left to be answered through non-experimental studies often because randomization is either infeasible or unethical. While methods such as propensity score matching can adjust for observed confounding, unobserved confounding is the Achilles heel of most non-experimental studies. This paper describes and illustrates seven sensitivity analysis techniques that assess the sensitivity of study results to an unobserved confounder. These methods were categorized into two groups to reflect differences in their conceptualization of sensitivity analysis, as well as their targets of interest. As a motivating example we examine the sensitivity of the association between maternal suicide and offspring’s risk for suicide attempt hospitalization. While inferences differed slightly depending on the type of sensitivity analysis conducted, overall the association between maternal suicide and offspring’s hospitalization for suicide attempt was found to be relatively robust to an unobserved confounder. The ease of implementation and the insight these analyses provide underscores sensitivity analysis techniques as an important tool for non-experimental studies. The implementation of sensitivity analysis can help increase confidence in results from non-experimental studies and better inform prevention researchers and policymakers regarding potential intervention targets. PMID:23408282

  6. An introduction to sensitivity analysis for unobserved confounding in nonexperimental prevention research.

    Science.gov (United States)

    Liu, Weiwei; Kuramoto, S Janet; Stuart, Elizabeth A

    2013-12-01

    Despite the fact that randomization is the gold standard for estimating causal relationships, many questions in prevention science are often left to be answered through nonexperimental studies because randomization is either infeasible or unethical. While methods such as propensity score matching can adjust for observed confounding, unobserved confounding is the Achilles heel of most nonexperimental studies. This paper describes and illustrates seven sensitivity analysis techniques that assess the sensitivity of study results to an unobserved confounder. These methods were categorized into two groups to reflect differences in their conceptualization of sensitivity analysis, as well as their targets of interest. As a motivating example, we examine the sensitivity of the association between maternal suicide and offspring's risk for suicide attempt hospitalization. While inferences differed slightly depending on the type of sensitivity analysis conducted, overall, the association between maternal suicide and offspring's hospitalization for suicide attempt was found to be relatively robust to an unobserved confounder. The ease of implementation and the insight these analyses provide underscores sensitivity analysis techniques as an important tool for nonexperimental studies. The implementation of sensitivity analysis can help increase confidence in results from nonexperimental studies and better inform prevention researchers and policy makers regarding potential intervention targets.

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

    Science.gov (United States)

    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. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    Coffman, Donna L.; Zhong, Wei

    2012-01-01

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

  9. Using ecological propensity score to adjust for missing confounders in small area studies.

    Science.gov (United States)

    Wang, Yingbo; Pirani, Monica; Hansell, Anna L; Richardson, Sylvia; Blangiardo, Marta

    2017-11-09

    Small area ecological studies are commonly used in epidemiology to assess the impact of area level risk factors on health outcomes when data are only available in an aggregated form. However, the resulting estimates are often biased due to unmeasured confounders, which typically are not available from the standard administrative registries used for these studies. Extra information on confounders can be provided through external data sets such as surveys or cohorts, where the data are available at the individual level rather than at the area level; however, such data typically lack the geographical coverage of administrative registries. We develop a framework of analysis which combines ecological and individual level data from different sources to provide an adjusted estimate of area level risk factors which is less biased. Our method (i) summarizes all available individual level confounders into an area level scalar variable, which we call ecological propensity score (EPS), (ii) implements a hierarchical structured approach to impute the values of EPS whenever they are missing, and (iii) includes the estimated and imputed EPS into the ecological regression linking the risk factors to the health outcome. Through a simulation study, we show that integrating individual level data into small area analyses via EPS is a promising method to reduce the bias intrinsic in ecological studies due to unmeasured confounders; we also apply the method to a real case study to evaluate the effect of air pollution on coronary heart disease hospital admissions in Greater London. © The Author 2017. Published by Oxford University Press.

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

    NARCIS (Netherlands)

    Jackson, D.; White, I.; Kostis, J.B.; Wilson, A.C.; Folsom, A.R.; Feskens, E.J.M.

    2009-01-01

    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

  11. The Association Between Headaches and Temporomandibular Disorders is Confounded by Bruxism and Somatic Symptoms.

    Science.gov (United States)

    van der Meer, Hedwig A; Speksnijder, Caroline M; Engelbert, Raoul H H; Lobbezoo, Frank; Nijhuis-van der Sanden, Maria W G; Visscher, Corine M

    2017-09-01

    The objective of this observational study was to establish the possible presence of confounders on the association between temporomandibular disorders (TMD) and headaches in a patient population from a TMD and Orofacial Pain Clinic. Several subtypes of headaches have been diagnosed: self-reported headache, (probable) migraine, (probable) tension-type headache, and secondary headache attributed to TMD. The presence of TMD was subdivided into 2 subtypes: painful TMD and function-related TMD. The associations between the subtypes of TMD and headaches were evaluated by single regression models. To study the influence of possible confounding factors on this association, the regression models were extended with age, sex, bruxism, stress, depression, and somatic symptoms. Of the included patients (n=203), 67.5% experienced headaches. In the subsample of patients with a painful TMD (n=58), the prevalence of self-reported headaches increased to 82.8%. The associations found between self-reported headache and (1) painful TMD and (2) function-related TMD were confounded by the presence of somatic symptoms. For probable migraine, both somatic symptoms and bruxism confounded the initial association found with painful TMD. The findings of this study imply that there is a central working mechanism overlapping TMD and headache. Health care providers should not regard these disorders separately, but rather look at the bigger picture to appreciate the complex nature of the diagnostic and therapeutic process.

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

    DEFF Research Database (Denmark)

    Jackson, D.; White, I.; Kostis, J.B.

    2009-01-01

    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...

  13. Medical versus surgical abortion: comparing satisfaction and potential confounders in a partly randomized study

    DEFF Research Database (Denmark)

    Rørbye, Christina; Nørgaard, Mogens; Nilas, Lisbeth

    2005-01-01

    BACKGROUND: The aim of the study was to compare satisfaction with medical and surgical abortion and to identify potential confounders affecting satisfaction. METHODS: 1033 women with gestational age (GA) < or = 63 days had either a medical (600 mg mifepristone followed by 1 mg gemeprost) or a sur...

  14. The Association between Headaches and Temporomandibular Disorders is Confounded by Bruxism and Somatic Complaints

    NARCIS (Netherlands)

    van der Meer, Hedwig A.; Speksnijder, Caroline M.; Engelbert, Raoul; Lobbezoo, Frank; Nijhuis – van der Sanden, Maria W G; Visscher, Corine M.

    OBJECTIVES:: The objective of this observational study was to establish the possible presence of confounders on the association between temporomandibular disorders (TMD) and headaches in a patient population from a TMD and Orofacial Pain Clinic. METHODS:: Several subtypes of headaches were

  15. The Association Between Headaches and Temporomandibular Disorders is Confounded by Bruxism and Somatic Symptoms

    NARCIS (Netherlands)

    Meer, H.A. van der; Speksnijder, C.M.; Engelbert, R.H.; Lobbezoo, F.; Nijhuis-Van der Sanden, M.W.G.; Visscher, C.M.

    2017-01-01

    OBJECTIVES: The objective of this observational study was to establish the possible presence of confounders on the association between temporomandibular disorders (TMD) and headaches in a patient population from a TMD and Orofacial Pain Clinic. MATERIALS AND METHODS: Several subtypes of headaches

  16. Cognitive effort: A neuroeconomic approach

    Science.gov (United States)

    Braver, Todd S.

    2015-01-01

    Cognitive effort has been implicated in numerous theories regarding normal and aberrant behavior and the physiological response to engagement with demanding tasks. Yet, despite broad interest, no unifying, operational definition of cognitive effort itself has been proposed. Here, we argue that the most intuitive and epistemologically valuable treatment is in terms of effort-based decision-making, and advocate a neuroeconomics-focused research strategy. We first outline psychological and neuroscientific theories of cognitive effort. Then we describe the benefits of a neuroeconomic research strategy, highlighting how it affords greater inferential traction than do traditional markers of cognitive effort, including self-reports and physiologic markers of autonomic arousal. Finally, we sketch a future series of studies that can leverage the full potential of the neuroeconomic approach toward understanding the cognitive and neural mechanisms that give rise to phenomenal, subjective cognitive effort. PMID:25673005

  17. What makes a reach movement effortful? Physical effort discounting supports common minimization principles in decision making and motor control.

    Directory of Open Access Journals (Sweden)

    Pierre Morel

    2017-06-01

    Full Text Available When deciding between alternative options, a rational agent chooses on the basis of the desirability of each outcome, including associated costs. As different options typically result in different actions, the effort associated with each action is an essential cost parameter. How do humans discount physical effort when deciding between movements? We used an action-selection task to characterize how subjective effort depends on the parameters of arm transport movements and controlled for potential confounding factors such as delay discounting and performance. First, by repeatedly asking subjects to choose between 2 arm movements of different amplitudes or durations, performed against different levels of force, we identified parameter combinations that subjects experienced as identical in effort (isoeffort curves. Movements with a long duration were judged more effortful than short-duration movements against the same force, while movement amplitudes did not influence effort. Biomechanics of the movements also affected effort, as movements towards the body midline were preferred to movements away from it. Second, by introducing movement repetitions, we further determined that the cost function for choosing between effortful movements had a quadratic relationship with force, while choices were made on the basis of the logarithm of these costs. Our results show that effort-based action selection during reaching cannot easily be explained by metabolic costs. Instead, force-loaded reaches, a widely occurring natural behavior, imposed an effort cost for decision making similar to cost functions in motor control. Our results thereby support the idea that motor control and economic choice are governed by partly overlapping optimization principles.

  18. Multidisciplinary Efforts Driving Translational Theranostics

    Science.gov (United States)

    Hu, Tony Y.

    2014-01-01

    This themed issue summarizes significant efforts aimed at using “biological language” to discern between “friends” and “foes” in the context of theranostics for true clinical application. It is expected that the success of theranostics depends on multidisciplinary efforts, combined to expedite our understanding of host responses to “customized” theranostic agents and formulating individualized therapies. PMID:25285169

  19. Learning Environment and Student Effort

    Science.gov (United States)

    Hopland, Arnt O.; Nyhus, Ole Henning

    2016-01-01

    Purpose: The purpose of this paper is to explore the relationship between satisfaction with learning environment and student effort, both in class and with homework assignments. Design/methodology/approach: The authors use data from a nationwide and compulsory survey to analyze the relationship between learning environment and student effort. The…

  20. Respiratory effort from the photoplethysmogram.

    Science.gov (United States)

    Addison, Paul S

    2017-03-01

    The potential for a simple, non-invasive measure of respiratory effort based on the pulse oximeter signal - the photoplethysmogram or 'pleth' - was investigated in a pilot study. Several parameters were developed based on a variety of manifestations of respiratory effort in the signal, including modulation changes in amplitude, baseline, frequency and pulse transit times, as well as distinct baseline signal shifts. Thirteen candidate parameters were investigated using data from healthy volunteers. Each volunteer underwent a series of controlled respiratory effort maneuvers at various set flow resistances and respiratory rates. Six oximeter probes were tested at various body sites. In all, over three thousand pleth-based effort-airway pressure (EP) curves were generated across the various airway constrictions, respiratory efforts, respiratory rates, subjects, probe sites, and the candidate parameters considered. Regression analysis was performed to determine the existence of positive monotonic relationships between the respiratory effort parameters and resulting airway pressures. Six of the candidate parameters investigated exhibited a distinct positive relationship (poximeter probe and an ECG (P2E-Effort) and the other using two pulse oximeter probes placed at different peripheral body sites (P2-Effort); and baseline shifts in heart rate, (BL-HR-Effort). In conclusion, a clear monotonic relationship was found between several pleth-based parameters and imposed respiratory loadings at the mouth across a range of respiratory rates and flow constrictions. The results suggest that the pleth may provide a measure of changing upper airway dynamics indicative of the effort to breathe. Copyright © 2017 The Author. Published by Elsevier Ltd.. All rights reserved.

  1. Effort rights-based management

    DEFF Research Database (Denmark)

    Squires, Dale; Maunder, Mark; Allen, Robin

    2017-01-01

    Effort rights-based fisheries management (RBM) is less widely used than catch rights, whether for groups or individuals. Because RBM on catch or effort necessarily requires a total allowable catch (TAC) or total allowable effort (TAE), RBM is discussed in conjunction with issues in assessing fish...... populations and providing TACs or TAEs. Both approaches have advantages and disadvantages, and there are trade-offs between the two approaches. In a narrow economic sense, catch rights are superior because of the type of incentives created, but once the costs of research to improve stock assessments...

  2. Neuropsychological functioning in older people with type 2 diabetes: the effect of controlling for confounding factors.

    Science.gov (United States)

    Asimakopoulou, K G; Hampson, S E; Morrish, N J

    2002-04-01

    Neuropsychological functioning was examined in a group of 33 older (mean age 62.40 +/- 9.62 years) people with Type 2 diabetes (Group 1) and 33 non-diabetic participants matched with Group 1 on age, sex, premorbid intelligence and presence of hypertension and cardio/cerebrovascular conditions (Group 2). Data statistically corrected for confounding factors obtained from the diabetic group were compared with the matched control group. The results suggested small cognitive deficits in diabetic people's verbal memory and mental flexibility (Logical Memory A and SS7). No differences were seen between the two samples in simple and complex visuomotor attention, sustained complex visual attention, attention efficiency, mental double tracking, implicit memory, and self-reported memory problems. These findings indicate minimal cognitive impairment in relatively uncomplicated Type 2 diabetes and demonstrate the importance of control and matching for confounding factors.

  3. A Comprehensive Analysis of the SRS-Schwab Adult Spinal Deformity Classification and Confounding Variables

    DEFF Research Database (Denmark)

    Hallager, Dennis Winge; Hansen, Lars Valentin; Dragsted, Casper Rokkjær

    2016-01-01

    STUDY DESIGN: Cross-sectional analyses on a consecutive, prospective cohort. OBJECTIVE: To evaluate the ability of the Scoliosis Research Society (SRS)-Schwab Adult Spinal Deformity Classification to group patients by widely used health-related quality-of-life (HRQOL) scores and examine possible...... to confounding. However, age group and aetiology had individual significant effects. CONCLUSION: The SRS-Schwab sagittal modifiers reliably grouped patients graded 0 versus + / +  + according to the most widely used HRQOL scores and the effects of increasing grade level on odds for worse ODI scores remained...... confounding variables. SUMMARY OF BACKGROUND DATA: The SRS-Schwab Adult Spinal Deformity Classification includes sagittal modifiers considered important for HRQOL and the clinical impact of the classification has been validated in patients from the International Spine Study Group database; however, equivocal...

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

    Science.gov (United States)

    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 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. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Overview of potential procedural and participant-related confounds for neuroimaging of the resting state

    Science.gov (United States)

    Duncan, Niall W.; Northoff, Georg

    2013-01-01

    Studies of intrinsic brain activity in the resting state have become increasingly common. A productive discussion of what analysis methods are appropriate, of the importance of physiologic correction and of the potential interpretations of results has been ongoing. However, less attention has been paid to factors other than physiologic noise that may confound resting-state experiments. These range from straightforward factors, such as ensuring that participants are all instructed in the same manner, to more obscure participant-related factors, such as body weight. We provide an overview of such potentially confounding factors, along with some suggested approaches for minimizing their impact. A particular theme that emerges from the overview is the range of systematic differences between types of study groups (e.g., between patients and controls) that may influence resting-state study results. PMID:22964258

  6. Syphilis may be a confounding factor, not a causative agent, in syphilitic ALS.

    Science.gov (United States)

    Tuk, Bert

    2016-01-01

    Based upon a review of published clinical observations regarding syphilitic amyotrophic lateral sclerosis (ALS), I hypothesize that syphilis is actually a confounding factor, not a causative factor, in syphilitic ALS. Moreover, I propose that the successful treatment of ALS symptoms in patients with syphilitic ALS using penicillin G and hydrocortisone is an indirect consequence of the treatment regimen and is not due to the treatment of syphilis. Specifically, I propose that the observed effect is due to the various pharmacological activities of penicillin G ( e.g ., a GABA receptor antagonist) and/or the multifaceted pharmacological activity of hydrocortisone. The notion that syphilis may be a confounding factor in syphilitic ALS is highly relevant, as it suggests that treating ALS patients with penicillin G and hydrocortisone-regardless of whether they present with syphilitic ALS or non-syphilitic ALS-may be effective at treating this rapidly progressive, highly devastating disease.

  7. Correction of confounding bias in non-randomized studies by appropriate weighting.

    Science.gov (United States)

    Schmoor, Claudia; Gall, Christine; Stampf, Susanne; Graf, Erika

    2011-03-01

    In non-randomized studies, the assessment of a causal effect of treatment or exposure on outcome is hampered by possible confounding. Applying multiple regression models including the effects of treatment and covariates on outcome is the well-known classical approach to adjust for confounding. In recent years other approaches have been promoted. One of them is based on the propensity score and considers the effect of possible confounders on treatment as a relevant criterion for adjustment. Another proposal is based on using an instrumental variable. Here inference relies on a factor, the instrument, which affects treatment but is thought to be otherwise unrelated to outcome, so that it mimics randomization. Each of these approaches can basically be interpreted as a simple reweighting scheme, designed to address confounding. The procedures will be compared with respect to their fundamental properties, namely, which bias they aim to eliminate, which effect they aim to estimate, and which parameter is modelled. We will expand our overview of methods for analysis of non-randomized studies to methods for analysis of randomized controlled trials and show that analyses of both study types may target different effects and different parameters. The considerations will be illustrated using a breast cancer study with a so-called Comprehensive Cohort Study design, including a randomized controlled trial and a non-randomized study in the same patient population as sub-cohorts. This design offers ideal opportunities to discuss and illustrate the properties of the different approaches. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Confounding Underlies the Apparent Month of Birth Effect in Multiple Sclerosis

    OpenAIRE

    Fiddes, Barnaby; Wason, James; Kemppinen, Anu; Ban, Maria; Compston, Alastair; Sawcer, Stephen

    2013-01-01

    Objective Several groups have reported apparent association between month of birth and multiple sclerosis. We sought to test the extent to which such studies might be confounded by extraneous variables such as year and place of birth. Methods Using national birth statistics from 2 continents, we assessed the evidence for seasonal variations in birth rate and tested the extent to which these are subject to regional and temporal variation. We then established the age and regional origin distrib...

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

    Directory of Open Access Journals (Sweden)

    Johanna M Walz

    Full Text Available 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.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.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.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.

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

    Science.gov (United States)

    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

    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. 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. 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. 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.

  11. Effect decomposition in the presence of an exposure-induced mediator-outcome confounder

    Science.gov (United States)

    VanderWeele, Tyler J.; Vansteelandt, Stijn; Robins, James M.

    2014-01-01

    Methods from causal mediation analysis have generalized the traditional approach to direct and indirect effects in the epidemiologic and social science literature by allowing for interaction and non-linearities. However, the methods from the causal inference literature have themselves been subject to a major limitation in that the so-called natural direct and indirect effects that are employed are not identified from data whenever there is a variable that is affected by the exposure, which also confounds the relationship between the mediator and the outcome. In this paper we describe three alternative approaches to effect decomposition that give quantities that can be interpreted as direct and indirect effects, and that can be identified from data even in the presence of an exposure-induced mediator-outcome confounder. We describe a simple weighting-based estimation method for each of these three approaches, illustrated with data from perinatal epidemiology. The methods described here can shed insight into pathways and questions of mediation even when an exposure-induced mediator-outcome confounder is present. PMID:24487213

  12. The Combined Effects of Measurement Error and Omitting Confounders in the Single-Mediator Model.

    Science.gov (United States)

    Fritz, Matthew S; Kenny, David A; MacKinnon, David P

    2016-01-01

    Mediation analysis requires a number of strong assumptions be met in order to make valid causal inferences. Failing to account for violations of these assumptions, such as not modeling measurement error or omitting a common cause of the effects in the model, can bias the parameter estimates of the mediated effect. When the independent variable is perfectly reliable, for example when participants are randomly assigned to levels of treatment, measurement error in the mediator tends to underestimate the mediated effect, while the omission of a confounding variable of the mediator-to-outcome relation tends to overestimate the mediated effect. Violations of these two assumptions often co-occur, however, in which case the mediated effect could be overestimated, underestimated, or even, in very rare circumstances, unbiased. To explore the combined effect of measurement error and omitted confounders in the same model, the effect of each violation on the single-mediator model is first examined individually. Then the combined effect of having measurement error and omitted confounders in the same model is discussed. Throughout, an empirical example is provided to illustrate the effect of violating these assumptions on the mediated effect.

  13. The relationship between urinary tract infection during pregnancy and preeclampsia: causal, confounded or spurious?

    Science.gov (United States)

    Karmon, Anatte; Sheiner, Eyal

    2008-06-01

    Preeclampsia is a major cause of maternal morbidity, although its precise etiology remains elusive. A number of studies suggest that urinary tract infection (UTI) during the course of gestation is associated with elevated risk for preeclampsia, while others have failed to prove such an association. In our medical center, pregnant women who were exposed to at least one UTI episode during pregnancy were 1.3 times more likely to have mild preeclampsia and 1.8 times more likely to have severe preeclampsia as compared to unexposed women. Our results are based on univariate analyses and are not adjusted for potential confounders. This editorial aims to discuss the relationship between urinary tract infection and preeclampsia, as well as examine the current problems regarding the interpretation of this association. Although the relationship between UTI and preeclampsia has been demonstrated in studies with various designs, carried-out in a variety of settings, the nature of this association is unclear. By taking into account timeline, dose-response effects, treatment influences, and potential confounders, as well as by neutralizing potential biases, future studies may be able to clarify the relationship between UTI and preeclampsia by determining if it is causal, confounded, or spurious.

  14. Assessing moderated mediation in linear models requires fewer confounding assumptions than assessing mediation.

    Science.gov (United States)

    Loeys, Tom; Talloen, Wouter; Goubert, Liesbet; Moerkerke, Beatrijs; Vansteelandt, Stijn

    2016-11-01

    It is well known from the mediation analysis literature that the identification of direct and indirect effects relies on strong no unmeasured confounding assumptions of no unmeasured confounding. Even in randomized studies the mediator may still be correlated with unobserved prognostic variables that affect the outcome, in which case the mediator's role in the causal process may not be inferred without bias. In the behavioural and social science literature very little attention has been given so far to the causal assumptions required for moderated mediation analysis. In this paper we focus on the index for moderated mediation, which measures by how much the mediated effect is larger or smaller for varying levels of the moderator. We show that in linear models this index can be estimated without bias in the presence of unmeasured common causes of the moderator, mediator and outcome under certain conditions. Importantly, one can thus use the test for moderated mediation to support evidence for mediation under less stringent confounding conditions. We illustrate our findings with data from a randomized experiment assessing the impact of being primed with social deception upon observer responses to others' pain, and from an observational study of individuals who ended a romantic relationship assessing the effect of attachment anxiety during the relationship on mental distress 2 years after the break-up. © 2016 The British Psychological Society.

  15. Enhancing the estimation of blood pressure using pulse arrival time and two confounding factors

    International Nuclear Information System (INIS)

    Baek, Hyun Jae; Kim, Ko Keun; Kim, Jung Soo; Lee, Boreom; Park, Kwang Suk

    2010-01-01

    A new method of blood pressure (BP) estimation using multiple regression with pulse arrival time (PAT) and two confounding factors was evaluated in clinical and unconstrained monitoring situations. For the first analysis with clinical data, electrocardiogram (ECG), photoplethysmogram (PPG) and invasive BP signals were obtained by a conventional patient monitoring device during surgery. In the second analysis, ECG, PPG and non-invasive BP were measured using systems developed to obtain data under conditions in which the subject was not constrained. To enhance the performance of BP estimation methods, heart rate (HR) and arterial stiffness were considered as confounding factors in regression analysis. The PAT and HR were easily extracted from ECG and PPG signals. For arterial stiffness, the duration from the maximum derivative point to the maximum of the dicrotic notch in the PPG signal, a parameter called TDB, was employed. In two experiments that normally cause BP variation, the correlation between measured BP and the estimated BP was investigated. Multiple-regression analysis with the two confounding factors improved correlation coefficients for diastolic blood pressure and systolic blood pressure to acceptable confidence levels, compared to existing methods that consider PAT only. In addition, reproducibility for the proposed method was determined using constructed test sets. Our results demonstrate that non-invasive, non-intrusive BP estimation can be obtained using methods that can be applied in both clinical and daily healthcare situations

  16. Enhancing the estimation of blood pressure using pulse arrival time and two confounding factors.

    Science.gov (United States)

    Baek, Hyun Jae; Kim, Ko Keun; Kim, Jung Soo; Lee, Boreom; Park, Kwang Suk

    2010-02-01

    A new method of blood pressure (BP) estimation using multiple regression with pulse arrival time (PAT) and two confounding factors was evaluated in clinical and unconstrained monitoring situations. For the first analysis with clinical data, electrocardiogram (ECG), photoplethysmogram (PPG) and invasive BP signals were obtained by a conventional patient monitoring device during surgery. In the second analysis, ECG, PPG and non-invasive BP were measured using systems developed to obtain data under conditions in which the subject was not constrained. To enhance the performance of BP estimation methods, heart rate (HR) and arterial stiffness were considered as confounding factors in regression analysis. The PAT and HR were easily extracted from ECG and PPG signals. For arterial stiffness, the duration from the maximum derivative point to the maximum of the dicrotic notch in the PPG signal, a parameter called TDB, was employed. In two experiments that normally cause BP variation, the correlation between measured BP and the estimated BP was investigated. Multiple-regression analysis with the two confounding factors improved correlation coefficients for diastolic blood pressure and systolic blood pressure to acceptable confidence levels, compared to existing methods that consider PAT only. In addition, reproducibility for the proposed method was determined using constructed test sets. Our results demonstrate that non-invasive, non-intrusive BP estimation can be obtained using methods that can be applied in both clinical and daily healthcare situations.

  17. The Combined Effects of Measurement Error and Omitting Confounders in the Single-Mediator Model

    Science.gov (United States)

    Fritz, Matthew S.; Kenny, David A.; MacKinnon, David P.

    2016-01-01

    Mediation analysis requires a number of strong assumptions be met in order to make valid causal inferences. Failing to account for violations of these assumptions, such as not modeling measurement error or omitting a common cause of the effects in the model, can bias the parameter estimates of the mediated effect. When the independent variable is perfectly reliable, for example when participants are randomly assigned to levels of treatment, measurement error in the mediator tends to underestimate the mediated effect, while the omission of a confounding variable of the mediator to outcome relation tends to overestimate the mediated effect. Violations of these two assumptions often co-occur, however, in which case the mediated effect could be overestimated, underestimated, or even, in very rare circumstances, unbiased. In order to explore the combined effect of measurement error and omitted confounders in the same model, the impact of each violation on the single-mediator model is first examined individually. Then the combined effect of having measurement error and omitted confounders in the same model is discussed. Throughout, an empirical example is provided to illustrate the effect of violating these assumptions on the mediated effect. PMID:27739903

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

    Science.gov (United States)

    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

  19. Pandemic Influenza: Domestic Preparedness Efforts

    National Research Council Canada - National Science Library

    Lister, Sarah A

    2005-01-01

    .... Though influenza pandemics occur with some regularity, and the United States has been involved in specific planning efforts since the early 1990s, the H5N1 situation has created a sense of urgency...

  20. Effort Estimation in BPMS Migration

    OpenAIRE

    Drews, Christopher; Lantow, Birger

    2018-01-01

    Usually Business Process Management Systems (BPMS) are highly integrated in the IT of organizations and are at the core of their business. Thus, migrating from one BPMS solution to another is not a common task. However, there are forces that are pushing organizations to perform this step, e.g. maintenance costs of legacy BPMS or the need for additional functionality. Before the actual migration, the risk and the effort must be evaluated. This work provides a framework for effort estimation re...

  1. Overlapping neural systems represent cognitive effort and reward anticipation.

    Science.gov (United States)

    Vassena, Eliana; Silvetti, Massimo; Boehler, Carsten N; Achten, Eric; Fias, Wim; Verguts, Tom

    2014-01-01

    Anticipating a potential benefit and how difficult it will be to obtain it are valuable skills in a constantly changing environment. In the human brain, the anticipation of reward is encoded by the Anterior Cingulate Cortex (ACC) and Striatum. Naturally, potential rewards have an incentive quality, resulting in a motivational effect improving performance. Recently it has been proposed that an upcoming task requiring effort induces a similar anticipation mechanism as reward, relying on the same cortico-limbic network. However, this overlapping anticipatory activity for reward and effort has only been investigated in a perceptual task. Whether this generalizes to high-level cognitive tasks remains to be investigated. To this end, an fMRI experiment was designed to investigate anticipation of reward and effort in cognitive tasks. A mental arithmetic task was implemented, manipulating effort (difficulty), reward, and delay in reward delivery to control for temporal confounds. The goal was to test for the motivational effect induced by the expectation of bigger reward and higher effort. The results showed that the activation elicited by an upcoming difficult task overlapped with higher reward prospect in the ACC and in the striatum, thus highlighting a pivotal role of this circuit in sustaining motivated behavior.

  2. Effort in Multitasking: Local and Global Assessment of Effort.

    Science.gov (United States)

    Kiesel, Andrea; Dignath, David

    2017-01-01

    When performing multiple tasks in succession, self-organization of task order might be superior compared to external-controlled task schedules, because self-organization allows optimizing processing modes and thus reduces switch costs, and it increases commitment to task goals. However, self-organization is an additional executive control process that is not required if task order is externally specified and as such it is considered as time-consuming and effortful. To compare self-organized and externally controlled task scheduling, we suggest assessing global subjective and objectives measures of effort in addition to local performance measures. In our new experimental approach, we combined characteristics of dual tasking settings and task switching settings and compared local and global measures of effort in a condition with free choice of task sequence and a condition with cued task sequence. In a multi-tasking environment, participants chose the task order while the task requirement of the not-yet-performed task remained the same. This task preview allowed participants to work on the previously non-chosen items in parallel and resulted in faster responses and fewer errors in task switch trials than in task repetition trials. The free-choice group profited more from this task preview than the cued group when considering local performance measures. Nevertheless, the free-choice group invested more effort than the cued group when considering global measures. Thus, self-organization in task scheduling seems to be effortful even in conditions in which it is beneficiary for task processing. In a second experiment, we reduced the possibility of task preview for the not-yet-performed tasks in order to hinder efficient self-organization. Here neither local nor global measures revealed substantial differences between the free-choice and a cued task sequence condition. Based on the results of both experiments, we suggest that global assessment of effort in addition to

  3. Dopamine, behavioral economics, and effort

    Directory of Open Access Journals (Sweden)

    John D Salamone

    2009-09-01

    Full Text Available Abstract. There are numerous problems with the hypothesis that brain dopamine (DA systems, particularly in the nucleus accumbens, directly mediate the rewarding or primary motivational characteristics of natural stimuli such as food. Research and theory related to the functions of mesolimbic DA are undergoing a substantial conceptual restructuring, with the traditional emphasis on hedonia and primary reward yielding to other concepts and lines of inquiry. The present review is focused upon the involvement of nucleus accumbens DA in behavioral activation and effort-related processes. Viewed from the framework of behavioral economics, the effects of accumbens DA depletions and antagonism on food-reinforced behavior are highly dependent upon the work requirements of the instrumental task, and DA depleted rats are more sensitive to increases in response costs (i.e., ratio requirements. Moreover, interference with accumbens DA transmission exerts a powerful influence over effort-related choice behavior. Rats with accumbens DA depletions or antagonism reallocate their instrumental behavior away from food-reinforced tasks that have high response requirements, and instead these rats select a less-effortful type of food-seeking behavior. Nucleus accumbens DA and adenosine interact in the regulation of effort-related functions, and other brain structures (anterior cingulate cortex, amygdala, ventral pallidum also are involved. Studies of the brain systems regulating effort-based processes may have implications for understanding drug abuse, as well as energy-related disorders such as psychomotor slowing, fatigue or anergia in depression and other neurological disorders.

  4. Maximum effort in the minimum-effort game

    Czech Academy of Sciences Publication Activity Database

    Engelmann, Dirk; Normann, H.-T.

    2010-01-01

    Roč. 13, č. 3 (2010), s. 249-259 ISSN 1386-4157 Institutional research plan: CEZ:AV0Z70850503 Keywords : minimum-effort game * coordination game * experiments * social capital Subject RIV: AH - Economics Impact factor: 1.868, year: 2010

  5. ASME Code Efforts Supporting HTGRs

    Energy Technology Data Exchange (ETDEWEB)

    D.K. Morton

    2012-09-01

    In 1999, an international collaborative initiative for the development of advanced (Generation IV) reactors was started. The idea behind this effort was to bring nuclear energy closer to the needs of sustainability, to increase proliferation resistance, and to support concepts able to produce energy (both electricity and process heat) at competitive costs. The U.S. Department of Energy has supported this effort by pursuing the development of the Next Generation Nuclear Plant, a high temperature gas-cooled reactor. This support has included research and development of pertinent data, initial regulatory discussions, and engineering support of various codes and standards development. This report discusses the various applicable American Society of Mechanical Engineers (ASME) codes and standards that are being developed to support these high temperature gascooled reactors during construction and operation. ASME is aggressively pursuing these codes and standards to support an international effort to build the next generation of advanced reactors so that all can benefit.

  6. ASME Code Efforts Supporting HTGRs

    Energy Technology Data Exchange (ETDEWEB)

    D.K. Morton

    2011-09-01

    In 1999, an international collaborative initiative for the development of advanced (Generation IV) reactors was started. The idea behind this effort was to bring nuclear energy closer to the needs of sustainability, to increase proliferation resistance, and to support concepts able to produce energy (both electricity and process heat) at competitive costs. The U.S. Department of Energy has supported this effort by pursuing the development of the Next Generation Nuclear Plant, a high temperature gas-cooled reactor. This support has included research and development of pertinent data, initial regulatory discussions, and engineering support of various codes and standards development. This report discusses the various applicable American Society of Mechanical Engineers (ASME) codes and standards that are being developed to support these high temperature gascooled reactors during construction and operation. ASME is aggressively pursuing these codes and standards to support an international effort to build the next generation of advanced reactors so that all can benefit.

  7. Effort Estimation in BPMS Migration

    Directory of Open Access Journals (Sweden)

    Christopher Drews

    2018-04-01

    Full Text Available Usually Business Process Management Systems (BPMS are highly integrated in the IT of organizations and are at the core of their business. Thus, migrating from one BPMS solution to another is not a common task. However, there are forces that are pushing organizations to perform this step, e.g. maintenance costs of legacy BPMS or the need for additional functionality. Before the actual migration, the risk and the effort must be evaluated. This work provides a framework for effort estimation regarding the technical aspects of BPMS migration. The framework provides questions for BPMS comparison and an effort evaluation schema. The applicability of the framework is evaluated based on a simplified BPMS migration scenario.

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

    Science.gov (United States)

    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

  9. Effort problem of chemical pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Okrajni, J.; Ciesla, M.; Mutwil, K. [Silesian Technical University, Katowice (Poland)

    1998-12-31

    The problem of the technical state assessment of the chemical pipelines working under mechanical and thermal loading has been shown in the paper. The pipelines effort after the long time operating period has been analysed. Material geometrical and loading conditions of the crack initiation and crack growth process in the chosen object has been discussed. Areas of the maximal effort have been determined. The material structure charges after the long time operating period have been described. Mechanisms of the crack initiation and crack growth in the pipeline elements have been analysed and mutual relations between the chemical and mechanical influences have been shown. (orig.) 16 refs.

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

    Science.gov (United States)

    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

  11. A comparison of Bayesian and Monte Carlo sensitivity analysis for unmeasured confounding.

    Science.gov (United States)

    McCandless, Lawrence C; Gustafson, Paul

    2017-08-15

    Bias from unmeasured confounding is a persistent concern in observational studies, and sensitivity analysis has been proposed as a solution. In the recent years, probabilistic sensitivity analysis using either Monte Carlo sensitivity analysis (MCSA) or Bayesian sensitivity analysis (BSA) has emerged as a practical analytic strategy when there are multiple bias parameters inputs. BSA uses Bayes theorem to formally combine evidence from the prior distribution and the data. In contrast, MCSA samples bias parameters directly from the prior distribution. Intuitively, one would think that BSA and MCSA ought to give similar results. Both methods use similar models and the same (prior) probability distributions for the bias parameters. In this paper, we illustrate the surprising finding that BSA and MCSA can give very different results. Specifically, we demonstrate that MCSA can give inaccurate uncertainty assessments (e.g. 95% intervals) that do not reflect the data's influence on uncertainty about unmeasured confounding. Using a data example from epidemiology and simulation studies, we show that certain combinations of data and prior distributions can result in dramatic prior-to-posterior changes in uncertainty about the bias parameters. This occurs because the application of Bayes theorem in a non-identifiable model can sometimes rule out certain patterns of unmeasured confounding that are not compatible with the data. Consequently, the MCSA approach may give 95% intervals that are either too wide or too narrow and that do not have 95% frequentist coverage probability. Based on our findings, we recommend that analysts use BSA for probabilistic sensitivity analysis. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  12. Role of environmental confounding in the association between FKBP5 and first-episode psychosis

    Directory of Open Access Journals (Sweden)

    Olesya eAjnakina

    2014-07-01

    Full Text Available Background: Failure to account for the etiological diversity that typically occurs in psychiatric cohorts may increase the potential for confounding, as a proportion of genetic variance will be specific to exposures that have variable distribution in cases. This study investigated whether minimizing the potential for such confounding strengthened the evidence for a genetic candidate currently unsupported at the genome-wide level.Methods: 291 first-episode psychosis cases from South London UK, and 218 unaffected controls were evaluated for a functional polymorphism at the rs1360780 locus in FKBP5. The relationship between FKBP5 and psychosis was modelled using logistic regression. Cannabis use (Cannabis Experiences Questionnaire and parental separation (Childhood Experience of Care and Abuse Questionnaire were modelled as confounders in the analysis.Results: Association at rs1360780 was not detected until the effects of the two environmental factors had been adjusted for in the model (OR=2.81, 95% CI 1.23-6.43, p=0.02. A statistical interaction between rs1360780 and parental separation was confirmed by stratified tests (OR=2.8, p=0.02 vs. OR=0.89, p=0.80. The genetic main effect was directionally-consistent with findings in other (stress-related clinical phenotypes. Moreover, the variation in effect magnitude was explained by the level of power associated with different cannabis constructs used in the model (r=0.95.Conclusions: Our results suggest that the extent to which genetic variants in FKBP5 can influence susceptibility to psychosis may depend on the other etiological factors involved. This finding requires further validation in other large independent cohorts. Potentially this work could have translational implications, as the ability to discriminate between genetic etiologies, based on a case-by-case understanding of exposure history would confer an important clinical advantage that would benefit the delivery of personalizable treatment

  13. Clinical and evoked pain, personality traits, and emotional states: can familial confounding explain the associations?

    Science.gov (United States)

    Strachan, Eric; Poeschla, Brian; Dansie, Elizabeth; Succop, Annemarie; Chopko, Laura; Afari, Niloofar

    2015-01-01

    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. 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. 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. 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. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. Bayesian inference in a discrete shock model using confounded common cause data

    International Nuclear Information System (INIS)

    Kvam, Paul H.; Martz, Harry F.

    1995-01-01

    We consider redundant systems of identical components for which reliability is assessed statistically using only demand-based failures and successes. Direct assessment of system reliability can lead to gross errors in estimation if there exist external events in the working environment that cause two or more components in the system to fail in the same demand period which have not been included in the reliability model. We develop a simple Bayesian model for estimating component reliability and the corresponding probability of common cause failure in operating systems for which the data is confounded; that is, the common cause failures cannot be distinguished from multiple independent component failures in the narrative event descriptions

  15. Consequences of exposure measurement error for confounder identification in environmental epidemiology

    DEFF Research Database (Denmark)

    Budtz-Jørgensen, Esben; Keiding, Niels; Grandjean, Philippe

    2003-01-01

    Non-differential measurement error in the exposure variable is known to attenuate the dose-response relationship. The amount of attenuation introduced in a given situation is not only a function of the precision of the exposure measurement but also depends on the conditional variance of the true...... exposure given the other independent variables. In addition, confounder effects may also be affected by the exposure measurement error. These difficulties in statistical model development are illustrated by examples from a epidemiological study performed in the Faroe Islands to investigate the adverse...

  16. Examining confounding by diet in the association between perfluoroalkyl acids and serum cholesterol in pregnancy

    International Nuclear Information System (INIS)

    Skuladottir, Margret; Ramel, Alfons; Rytter, Dorte; Haug, Line Småstuen; Sabaredzovic, Azemira; Bech, Bodil Hammer; Henriksen, Tine Brink; Olsen, Sjurdur F.; Halldorsson, Thorhallur I.

    2015-01-01

    Background: Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) have consistently been associated with higher cholesterol levels in cross sectional studies. Concerns have, however, been raised about potential confounding by diet and clinical relevance. Objective: To examine the association between concentrations of PFOS and PFOA and total cholesterol in serum during pregnancy taking into considerations confounding by diet. Methods: 854 Danish women who gave birth in 1988–89 and provided a blood sample and reported their diet in week 30 of gestation. Results: Mean serum PFOS, PFOA and total cholesterol concentrations were 22.3 ng/mL, 4.1 ng/mL and 7.3 mmol/L, respectively. Maternal diet was a significant predictor of serum PFOS and PFOA concentrations. In particular intake of meat and meat products was positively associated while intake of vegetables was inversely associated (P for trend <0.01) with relative difference between the highest and lowest quartile in PFOS and PFOA concentrations ranging between 6% and 25% of mean values. After adjustment for dietary factors both PFOA and PFOS were positively and similarly associated with serum cholesterol (P for trend ≤0.01). For example, the mean increase in serum cholesterol was 0.39 mmol/L (95%CI: 0.09, 0.68) when comparing women in the highest to lowest quintile of PFOA concentrations. In comparison the mean increase in serum cholesterol was 0.61 mmol/L (95%CI: 0.17, 1.05) when comparing women in the highest to lowest quintile of saturated fat intake. Conclusion: In this study associations between PFOS and PFOA with serum cholesterol appeared unrelated to dietary intake and were similar in magnitude as the associations between saturated fat intake and serum cholesterol. - Highlights: • PFOS and PFOA have consistently been linked with raised serum cholesterol • Clinical relevance remains uncertain and confounding by diet has been suggested • The aim of this study was to address these issues in

  17. Examining confounding by diet in the association between perfluoroalkyl acids and serum cholesterol in pregnancy

    Energy Technology Data Exchange (ETDEWEB)

    Skuladottir, Margret; Ramel, Alfons [Faculty of Food Science and Nutrition, University of Iceland, Reykjavik (Iceland); Unit for Nutrition Research, Landspitali National University Hospital, Reykjavik (Iceland); Rytter, Dorte [Department of Public Health, Section for Epidemiology, Aarhus University, Aarhus (Denmark); Haug, Line Småstuen; Sabaredzovic, Azemira [Division of Environmental Medicine, Norwegian Institute of Public Health, Oslo (Norway); Bech, Bodil Hammer [Department of Public Health, Section for Epidemiology, Aarhus University, Aarhus (Denmark); Henriksen, Tine Brink [Pediatric Department, Aarhus University Hospital, Aarhus (Denmark); Olsen, Sjurdur F. [Center for Fetal Programming, Department of Epidemiology Research, Statens Serum Institut, Copenhagen (Denmark); Department of Nutrition, Harvard School of Public Health, Boston, MA (United States); Halldorsson, Thorhallur I., E-mail: tih@hi.is [Faculty of Food Science and Nutrition, University of Iceland, Reykjavik (Iceland); Unit for Nutrition Research, Landspitali National University Hospital, Reykjavik (Iceland); Center for Fetal Programming, Department of Epidemiology Research, Statens Serum Institut, Copenhagen (Denmark)

    2015-11-15

    Background: Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) have consistently been associated with higher cholesterol levels in cross sectional studies. Concerns have, however, been raised about potential confounding by diet and clinical relevance. Objective: To examine the association between concentrations of PFOS and PFOA and total cholesterol in serum during pregnancy taking into considerations confounding by diet. Methods: 854 Danish women who gave birth in 1988–89 and provided a blood sample and reported their diet in week 30 of gestation. Results: Mean serum PFOS, PFOA and total cholesterol concentrations were 22.3 ng/mL, 4.1 ng/mL and 7.3 mmol/L, respectively. Maternal diet was a significant predictor of serum PFOS and PFOA concentrations. In particular intake of meat and meat products was positively associated while intake of vegetables was inversely associated (P for trend <0.01) with relative difference between the highest and lowest quartile in PFOS and PFOA concentrations ranging between 6% and 25% of mean values. After adjustment for dietary factors both PFOA and PFOS were positively and similarly associated with serum cholesterol (P for trend ≤0.01). For example, the mean increase in serum cholesterol was 0.39 mmol/L (95%CI: 0.09, 0.68) when comparing women in the highest to lowest quintile of PFOA concentrations. In comparison the mean increase in serum cholesterol was 0.61 mmol/L (95%CI: 0.17, 1.05) when comparing women in the highest to lowest quintile of saturated fat intake. Conclusion: In this study associations between PFOS and PFOA with serum cholesterol appeared unrelated to dietary intake and were similar in magnitude as the associations between saturated fat intake and serum cholesterol. - Highlights: • PFOS and PFOA have consistently been linked with raised serum cholesterol • Clinical relevance remains uncertain and confounding by diet has been suggested • The aim of this study was to address these issues in

  18. Confounding and Statistical Significance of Indirect Effects: Childhood Adversity, Education, Smoking, and Anxious and Depressive Symptomatology

    Directory of Open Access Journals (Sweden)

    Mashhood Ahmed Sheikh

    2017-08-01

    Full Text Available The life course perspective, the risky families model, and stress-and-coping models provide the rationale for assessing the role of smoking as a mediator in the association between childhood adversity and anxious and depressive symptomatology (ADS in adulthood. However, no previous study has assessed the independent mediating role of smoking in the association between childhood adversity and ADS in adulthood. Moreover, the importance of mediator-response confounding variables has rarely been demonstrated empirically in social and psychiatric epidemiology. The aim of this paper was to (i assess the mediating role of smoking in adulthood in the association between childhood adversity and ADS in adulthood, and (ii assess the change in estimates due to different mediator-response confounding factors (education, alcohol intake, and social support. The present analysis used data collected from 1994 to 2008 within the framework of the Tromsø Study (N = 4,530, a representative prospective cohort study of men and women. Seven childhood adversities (low mother's education, low father's education, low financial conditions, exposure to passive smoke, psychological abuse, physical abuse, and substance abuse distress were used to create a childhood adversity score. Smoking status was measured at a mean age of 54.7 years (Tromsø IV, and ADS in adulthood was measured at a mean age of 61.7 years (Tromsø V. Mediation analysis was used to assess the indirect effect and the proportion of mediated effect (% of childhood adversity on ADS in adulthood via smoking in adulthood. The test-retest reliability of smoking was good (Kappa: 0.67, 95% CI: 0.63; 0.71 in this sample. Childhood adversity was associated with a 10% increased risk of smoking in adulthood (Relative risk: 1.10, 95% CI: 1.03; 1.18, and both childhood adversity and smoking in adulthood were associated with greater levels of ADS in adulthood (p < 0.001. Smoking in adulthood did not significantly

  19. Recommendations to standardize preanalytical confounding factors in Alzheimer's and Parkinson's disease cerebrospinal fluid biomarkers

    DEFF Research Database (Denmark)

    del Campo, Marta; Mollenhauer, Brit; Bertolotto, Antonio

    2012-01-01

    Early diagnosis of neurodegenerative disorders such as Alzheimer's (AD) or Parkinson's disease (PD) is needed to slow down or halt the disease at the earliest stage. Cerebrospinal fluid (CSF) biomarkers can be a good tool for early diagnosis. However, their use in clinical practice is challenging...... the need to establish standardized operating procedures. Here, we merge two previous consensus guidelines for preanalytical confounding factors in order to achieve one exhaustive guideline updated with new evidence for Aβ42, total tau and phosphorylated tau, and α-synuclein. The proposed standardized...

  20. Reproductive effort in viscous populations

    NARCIS (Netherlands)

    Pen, Ido

    Here I study a kin selection model of reproductive effort, the allocation of resources to fecundity versus survival, in a patch-structured population. Breeding females remain in the same patch for life. Offspring have costly, partial long-distance dispersal and compete for breeding sites, which

  1. High blood pressure and sedentary behavior in adolescents are associated even after controlling for confounding factors.

    Science.gov (United States)

    Christofaro, Diego Giulliano Destro; De Andrade, Selma Maffei; Cardoso, Jefferson Rosa; Mesas, Arthur Eumann; Codogno, Jamile Sanches; Fernandes, Rômulo Araújo

    2015-01-01

    The aim of this study was to determine whether high blood pressure (HBP) is associated with sedentary behavior in young people even after controlling for potential confounders (gender, age, socioeconomic level, tobacco, alcohol, obesity and physical activity). In this epidemiological study, 1231 adolescents were evaluated. Blood pressure was measured with an oscillometric device and waist circumference with an inextensible tape. Sedentary behavior (watching television, computer use and playing video games) and physical activity were assessed by a questionnaire. We used mean and standard deviation to describe the statistical analysis, and the association between HBP and sedentary behavior was assessed by the chi-squared test. Binary logistic regression was used to observe the magnitude of association and cluster analyses (sedentary behavior and abdominal obesity; sedentary behavior and physical inactivity). HBP was associated with sedentary behaviors [odds ratio (OR) = 2.21, 95% confidence interval (CI) = 1.41-3.96], even after controlling for various confounders (OR = 1.68, CI = 1.03-2.75). In cluster analysis the combination of sedentary behavior and elevated abdominal obesity contributed significantly to an increased likelihood of having HBP (OR = 13.51, CI 7.21-23.97). Sedentary behavior was associated with HBP, and excess fat in the abdominal region contributed to the modulation of this association.

  2. Sensitivity analysis for unobserved confounding of direct and indirect effects using uncertainty intervals.

    Science.gov (United States)

    Lindmark, Anita; de Luna, Xavier; Eriksson, Marie

    2018-05-10

    To estimate direct and indirect effects of an exposure on an outcome from observed data, strong assumptions about unconfoundedness are required. Since these assumptions cannot be tested using the observed data, a mediation analysis should always be accompanied by a sensitivity analysis of the resulting estimates. In this article, we propose a sensitivity analysis method for parametric estimation of direct and indirect effects when the exposure, mediator, and outcome are all binary. The sensitivity parameters consist of the correlations between the error terms of the exposure, mediator, and outcome models. These correlations are incorporated into the estimation of the model parameters and identification sets are then obtained for the direct and indirect effects for a range of plausible correlation values. We take the sampling variability into account through the construction of uncertainty intervals. The proposed method is able to assess sensitivity to both mediator-outcome confounding and confounding involving the exposure. To illustrate the method, we apply it to a mediation study based on the data from the Swedish Stroke Register (Riksstroke). An R package that implements the proposed method is available. Copyright © 2018 John Wiley & Sons, Ltd.

  3. Everything that you have ever been told about assessment center ratings is confounded.

    Science.gov (United States)

    Jackson, Duncan J R; Michaelides, George; Dewberry, Chris; Kim, Young-Jae

    2016-07-01

    Despite a substantial research literature on the influence of dimensions and exercises in assessment centers (ACs), the relative impact of these 2 sources of variance continues to raise uncertainties because of confounding. With confounded effects, it is not possible to establish the degree to which any 1 effect, including those related to exercises and dimensions, influences AC ratings. In the current study (N = 698) we used Bayesian generalizability theory to unconfound all of the possible effects contributing to variance in AC ratings. Our results show that ≤1.11% of the variance in AC ratings was directly attributable to behavioral dimensions, suggesting that dimension-related effects have no practical impact on the reliability of ACs. Even when taking aggregation level into consideration, effects related to general performance and exercises accounted for almost all of the reliable variance in AC ratings. The implications of these findings for recent dimension- and exercise-based perspectives on ACs are discussed. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  4. No evidence for thermal transgenerational plasticity in metabolism when minimizing the potential for confounding effects.

    Science.gov (United States)

    Kielland, Ø N; Bech, C; Einum, S

    2017-01-11

    Environmental change may cause phenotypic changes that are inherited across generations through transgenerational plasticity (TGP). If TGP is adaptive, offspring fitness increases with an increasing match between parent and offspring environment. Here we test for adaptive TGP in somatic growth and metabolic rate in response to temperature in the clonal zooplankton Daphnia pulex Animals of the first focal generation experienced thermal transgenerational 'mismatch' (parental and offspring temperatures differed), whereas conditions of the next two generations matched the (grand)maternal thermal conditions. Adjustments of metabolic rate occurred during the lifetime of the first generation (i.e. within-generation plasticity). However, no further change was observed during the subsequent two generations, as would be expected under TGP. Furthermore, we observed no tendency for increased juvenile somatic growth (a trait highly correlated with fitness in Daphnia) over the three generations when reared at new temperatures. These results are inconsistent with existing studies of thermal TGP, and we describe how previous experimental designs may have confounded TGP with within-generation plasticity and selective mortality. We suggest that the current evidence for thermal TGP is weak. To increase our understanding of the ecological and evolutionary role of TGP, future studies should more carefully identify possible confounding factors. © 2017 The Author(s).

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

    International Nuclear Information System (INIS)

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

    2012-01-01

    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. Highlights: ► Study of potential bias associated with the use of infected zebra mussels in ecotoxicological studies. ► Presence of infected mussels on banks and channels, up- and downstream a waste water treatment plant. ► Parasitism influence on biological responses dependent of mussel population history. ► Integrative index, an interesting tool to synthesize the set of biological data. - Parasitism influence on the host physiology would be strongly dependent on environmental conditions but remains a potential confounding factor in ecotoxicological studies.

  6. On the Confounding Effect of Temperature on Chemical Shift-Encoded Fat Quantification

    Science.gov (United States)

    Hernando, Diego; Sharma, Samir D.; Kramer, Harald; Reeder, Scott B.

    2014-01-01

    Purpose To characterize the confounding effect of temperature on chemical shift-encoded (CSE) fat quantification. Methods The proton resonance frequency of water, unlike triglycerides, depends on temperature. This leads to a temperature dependence of the spectral models of fat (relative to water) that are commonly used by CSE-MRI methods. Simulation analysis was performed for 1.5 Tesla CSE fat–water signals at various temperatures and echo time combinations. Oil–water phantoms were constructed and scanned at temperatures between 0 and 40°C using spectroscopy and CSE imaging at three echo time combinations. An explanted human liver, rejected for transplantation due to steatosis, was scanned using spectroscopy and CSE imaging. Fat–water reconstructions were performed using four different techniques: magnitude and complex fitting, with standard or temperature-corrected signal modeling. Results In all experiments, magnitude fitting with standard signal modeling resulted in large fat quantification errors. Errors were largest for echo time combinations near TEinit ≈ 1.3 ms, ΔTE ≈ 2.2 ms. Errors in fat quantification caused by temperature-related frequency shifts were smaller with complex fitting, and were avoided using a temperature-corrected signal model. Conclusion Temperature is a confounding factor for fat quantification. If not accounted for, it can result in large errors in fat quantifications in phantom and ex vivo acquisitions. PMID:24123362

  7. Fresh fruit intake and asthma symptoms in young British adults: confounding or effect modification by smoking?

    Science.gov (United States)

    Butland, B K; Strachan, D P; Anderson, H R

    1999-04-01

    Antioxidant vitamins have been postulated as a protective factor in asthma. The associations between the frequency of fresh fruit consumption in summer, and the prevalence of self-reported asthma symptoms were investigated. The analysis was based on 5,582 males and 5,770 females, born in England, Wales and Scotland between March 3-9, 1958 and aged 33 yrs at the time of survey. The 12-month period prevalence of wheeze and frequent wheeze were inversely associated with frequent intakes of fresh fruit and salad/raw vegetables and positively associated with smoking and lower social class. After adjustment for mutual confounding and sex, associations with smoking persisted, but those with social class and salad/raw vegetable consumption lost significance. The frequency of fresh fruit intake was no longer associated with wheeze after adjustment, but was inversely associated with frequent wheeze and speech-limiting attacks. The association with frequent wheeze differed significantly between smoking groups (never, former, current) and appeared to be confined to exsmokers and current smokers. These findings support postulated associations between infrequent fresh fruit consumption and the prevalence of frequent or severe asthma symptoms in adults. Associations appeared to be restricted to smokers, with effect modification as a more likely explanation of this pattern than residual confounding by smoking.

  8. Offspring ADHD as a risk factor for parental marital problems: controls for genetic and environmental confounds.

    Science.gov (United States)

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

    2012-12-01

    Previous studies have found that child attention-deficit/hyperactivity disorder (ADHD) is associated with more parental marital problems. However, the reasons for this association are unclear. The association might be due to genetic or environmental confounds that contribute to both marital problems and ADHD. Data were drawn from the Australian Twin Registry, including 1,296 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. 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. 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.

  9. External radiation dose and cancer mortality among French nuclear workers. Considering potential confounding by internal radiation exposure

    Energy Technology Data Exchange (ETDEWEB)

    Fournier, L.; Laurent, O.; Samson, E.; Caer-Lorho, S.; Laurier, D.; Leuraud, K. [Institute for Radiological Protection and Nuclear Safety, Fontenay aux Roses (France). Ionizing Radiation Epidemiology Lab.; Laroche, P. [AREVA, Paris (France); Le Guen, B. [EDF, Saint Denis (France)

    2016-11-15

    French nuclear workers have detailed records of their occupational exposure to external radiation that have been used to examine associations with subsequent cancer mortality. However, some workers were also exposed to internal contamination by radionuclides. This study aims to assess the potential for bias due to confounding by internal contamination of estimates of associations between external radiation exposure and cancer mortality. A cohort of 59,004 workers employed for at least 1 year between 1950 and 1994 by CEA (Commissariat a l'Energie Atomique), AREVA NC, or EDF (Electricite de France) and badge-monitored for external radiation exposure were followed through 2004 to assess vital status and cause of death. A flag based on a workstation-exposure matrix defined four levels of potential for internal contamination. Standardized mortality ratios were assessed for each level of the internal contamination indicator. Poisson regression was used to quantify associations between external radiation exposure and cancer mortality, adjusting for potential internal contamination. For solid cancer, the mortality deficit tended to decrease as the levels of potential for internal contamination increased. For solid cancer and leukemia excluding chronic lymphocytic leukemia, adjusting the dose-response analysis on the internal contamination indicator did not markedly change the excess relative risk per Sievert of external radiation dose. This study suggests that in this cohort, neglecting information on internal dosimetry while studying the association between external dose and cancer mortality does not generate a substantial bias. To investigate more specifically the health effects of internal contamination, an effort is underway to estimate organ doses due to internal contamination.

  10. External radiation dose and cancer mortality among French nuclear workers: considering potential confounding by internal radiation exposure.

    Science.gov (United States)

    Fournier, L; Laurent, O; Samson, E; Caër-Lorho, S; Laroche, P; Le Guen, B; Laurier, D; Leuraud, K

    2016-11-01

    French nuclear workers have detailed records of their occupational exposure to external radiation that have been used to examine associations with subsequent cancer mortality. However, some workers were also exposed to internal contamination by radionuclides. This study aims to assess the potential for bias due to confounding by internal contamination of estimates of associations between external radiation exposure and cancer mortality. A cohort of 59,004 workers employed for at least 1 year between 1950 and 1994 by CEA (Commissariat à l'Energie Atomique), AREVA NC, or EDF (Electricité de France) and badge-monitored for external radiation exposure were followed through 2004 to assess vital status and cause of death. A flag based on a workstation-exposure matrix defined four levels of potential for internal contamination. Standardized mortality ratios were assessed for each level of the internal contamination indicator. Poisson regression was used to quantify associations between external radiation exposure and cancer mortality, adjusting for potential internal contamination. For solid cancer, the mortality deficit tended to decrease as the levels of potential for internal contamination increased. For solid cancer and leukemia excluding chronic lymphocytic leukemia, adjusting the dose-response analysis on the internal contamination indicator did not markedly change the excess relative risk per Sievert of external radiation dose. This study suggests that in this cohort, neglecting information on internal dosimetry while studying the association between external dose and cancer mortality does not generate a substantial bias. To investigate more specifically the health effects of internal contamination, an effort is underway to estimate organ doses due to internal contamination.

  11. Correlation between radon level and confounders of cancer. A note on epidemiological inference at low doses

    International Nuclear Information System (INIS)

    Hajnal, M.A.; Toth, E.; Hamori, K.; Minda, M.; Koteles, Gy.J.

    2007-01-01

    Complete text of publication follows. Objective. The aim of this study was to examine and further clarify the extent of radon and progeny induced carcinogenesis, both separated from and combined with other confounders and health risk factors. This work was financed by National Development Agency, Hungary, with GVOP-3.1.1.-2004-05-0384/3.0. Methods. A case-control study was conducted in a Hungarian countryside region where the proportion of houses with yearly average radon level above 200 Bq.m -3 was estimated to be higher than 20% by our preceding regional surveys. Radon levels were measured with CR39 closed etched detectors for three seasons separately yielding yearly average by estimating the low summer level. The detectors were placed in the bedrooms, where people were expected to spend one third of a day. 520 patients with diagnosed cancers were included in these measurements, amongst which 77 developed lung or respiratory cancers. The control group consisted 6333 individuals, above 30 years of age. Lifestyle risk factors of cancers were collected by surveys including social status, pollution from indoor heating, smoking and alcohol history, nutrition, exercise and mental health index 5. Except smoking and alcohol habits, these cofactors were only available for the control group. Comparing disease occurrences the authors selected the multivariate generalised linear models. The case and control proportions along a given factor are binomially distributed, thus the logit link function was used. For radon both log and linear terms were probed for. Results. Many known health confounders of cancers correlated with radon levels, with an estimated total net increase of 50-150 Bq m -3 with increased risks. For lung cancers the model with the terms radon, age, gender and smoking was found to have the lowest Akaike Information Criterion (AIC). Heavy dependency on age, gender and smoking contribute largely to observed lung cancer incidence. However log linear relationship

  12. Familial confounding of the association between maternal smoking during pregnancy and offspring substance use and problems.

    Science.gov (United States)

    D'Onofrio, Brian M; Rickert, Martin E; Langström, Niklas; Donahue, Kelly L; Coyne, Claire A; Larsson, Henrik; Ellingson, Jarrod M; Van Hulle, Carol A; Iliadou, Anastasia N; Rathouz, Paul J; Lahey, Benjamin B; Lichtenstein, Paul

    2012-11-01

    Previous epidemiological, animal, and human cognitive neuroscience research suggests that maternal smoking during pregnancy (SDP) causes increased risk of substance use/problems in offspring. To determine the extent to which the association between SDP and offspring substance use/problems depends on confounded familial background factors by using a quasi-experimental design. We used 2 separate samples from the United States and Sweden. The analyses prospectively predicted multiple indices of substance use and problems while controlling for statistical covariates and comparing differentially exposed siblings to minimize confounding. Offspring of a representative sample of women in the United States (sample 1) and the total Swedish population born during the period from January 1, 1983, to December 31, 1995 (sample 2). Adolescent offspring of the women in the National Longitudinal Survey of Youth 1979 (n = 6904) and all offspring born in Sweden during the 13-year period (n = 1,187,360). Self-reported adolescent alcohol, cigarette, and marijuana use and early onset (before 14 years of age) of each substance (sample 1) and substance-related convictions and hospitalizations for an alcohol- or other drug-related problem (sample 2). The same pattern emerged for each index of substance use/problems across the 2 samples. At the population level, maternal SDP predicted every measure of offspring substance use/problems in both samples, ranging from adolescent alcohol use (hazard ratio [HR](moderate), 1.32 [95% CI, 1.22-1.43]; HR(high), 1.33 [1.17-1.53]) to a narcotics-related conviction (HR(moderate), 2.23 [2.14-2.31]; HR(high), 2.97 [2.86-3.09]). When comparing differentially exposed siblings to minimize genetic and environmental confounds, however, the association between SDP and each measure of substance use/problems was minimal and not statistically significant. The association between maternal SDP and offspring substance use/problems is likely due to familial background

  13. Voluntary versus Enforced Team Effort

    Directory of Open Access Journals (Sweden)

    Claudia Keser

    2011-08-01

    Full Text Available We present a model where each of two players chooses between remuneration based on either private or team effort. Although at least one of the players has the equilibrium strategy to choose private remuneration, we frequently observe both players to choose team remuneration in a series of laboratory experiments. This allows for high cooperation payoffs but also provides individual free-riding incentives. Due to significant cooperation, we observe that, in team remuneration, participants make higher profits than in private remuneration. We also observe that, when participants are not given the option of private remuneration, they cooperate significantly less.

  14. Intratumoral heterogeneity as a confounding factor in clonogenic assays for tumour radioresponsiveness

    International Nuclear Information System (INIS)

    Britten, R.A.; Evans, A.J.; Allalunis-Turner, M.J.; Franko, A.J.; Pearcey, R.G.

    1996-01-01

    The level of intra-tumoral heterogeneity of cellular radiosensitivity within primary cultures of three carcinomas of the cervix has been established. All three cultures contained clones that varied by as much as 3-fold in their clinically relevant radiosensitivity (SF 2 ). The level of intra-tumoral heterogeneity observed in these cervical tumour cultures was sufficient to be a major confounding factor to the use of pre-treatment assessments of radiosensitivity to predict for clinical radioresponsiveness. Mathematical modeling of the relative elimination of the tumour clones during fractionated radiotherapy indicates that, in two of the three biopsy samples, the use of pre-treatment derived SF 2 values from the heterogeneous tumour sample would significantly overestimate radioresponsiveness. We conclude that assays of cellular radiosensitivity that identify the radiosensitivity of the most radioresistant clones and measure their relative abundance could potentially increase the effectiveness of SF 2 values as a predictive marker of radioresponsiveness

  15. Non-Chemical Distant Cellular Interactions as a potential confounder of Cell Biology Experiments

    Directory of Open Access Journals (Sweden)

    Ashkan eFarhadi

    2014-10-01

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

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

    Science.gov (United States)

    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. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. Which Propensity Score Method Best Reduces Confounder Imbalance? An Example From a Retrospective Evaluation of a Childhood Obesity Intervention.

    Science.gov (United States)

    Schroeder, Krista; Jia, Haomiao; Smaldone, Arlene

    Propensity score (PS) methods are increasingly being employed by researchers to reduce bias arising from confounder imbalance when using observational data to examine intervention effects. The purpose of this study was to examine PS theory and methodology and compare application of three PS methods (matching, stratification, weighting) to determine which best improves confounder balance. Baseline characteristics of a sample of 20,518 school-aged children with severe obesity (of whom 1,054 received an obesity intervention) were assessed prior to PS application. Three PS methods were then applied to the data to determine which showed the greatest improvement in confounder balance between the intervention and control group. The effect of each PS method on the outcome variable-body mass index percentile change at one year-was also examined. SAS 9.4 and Comprehensive Meta-analysis statistical software were used for analyses. Prior to PS adjustment, the intervention and control groups differed significantly on seven of 11 potential confounders. PS matching removed all differences. PS stratification and weighting both removed one difference but created two new differences. Sensitivity analyses did not change these results. Body mass index percentile at 1 year decreased in both groups. The size of the decrease was smaller in the intervention group, and the estimate of the decrease varied by PS method. Selection of a PS method should be guided by insight from statistical theory and simulation experiments, in addition to observed improvement in confounder balance. For this data set, PS matching worked best to correct confounder imbalance. Because each method varied in correcting confounder imbalance, we recommend that multiple PS methods be compared for ability to improve confounder balance before implementation in evaluating treatment effects in observational data.

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

    Science.gov (United States)

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

    2016-09-01

    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. 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. miProfile software is freely available at https://medschool.vanderbilt.edu/tang-lab/software/miProfile z.tang@vanderbilt.edu or g.chen@vanderbilt.edu Supplementary data are available at Bioinformatics online. © The Author 2016. Published by Oxford University Press.

  19. Adjusting for Confounding in Early Postlaunch Settings: Going Beyond Logistic Regression Models.

    Science.gov (United States)

    Schmidt, Amand F; Klungel, Olaf H; Groenwold, Rolf H H

    2016-01-01

    Postlaunch data on medical treatments can be analyzed to explore adverse events or relative effectiveness in real-life settings. These analyses are often complicated by the number of potential confounders and the possibility of model misspecification. We conducted a simulation study to compare the performance of logistic regression, propensity score, disease risk score, and stabilized inverse probability weighting methods to adjust for confounding. Model misspecification was induced in the independent derivation dataset. We evaluated performance using relative bias confidence interval coverage of the true effect, among other metrics. At low events per coefficient (1.0 and 0.5), the logistic regression estimates had a large relative bias (greater than -100%). Bias of the disease risk score estimates was at most 13.48% and 18.83%. For the propensity score model, this was 8.74% and >100%, respectively. At events per coefficient of 1.0 and 0.5, inverse probability weighting frequently failed or reduced to a crude regression, resulting in biases of -8.49% and 24.55%. Coverage of logistic regression estimates became less than the nominal level at events per coefficient ≤5. For the disease risk score, inverse probability weighting, and propensity score, coverage became less than nominal at events per coefficient ≤2.5, ≤1.0, and ≤1.0, respectively. Bias of misspecified disease risk score models was 16.55%. In settings with low events/exposed subjects per coefficient, disease risk score methods can be useful alternatives to logistic regression models, especially when propensity score models cannot be used. Despite better performance of disease risk score methods than logistic regression and propensity score models in small events per coefficient settings, bias, and coverage still deviated from nominal.

  20. Interpretational confounding is due to misspecification, not to type of indicator: comment on Howell, Breivik, and Wilcox (2007).

    Science.gov (United States)

    Bollen, Kenneth A

    2007-06-01

    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 (formative) indicators rests on several claims: (a) A latent variable exists apart from the model when there are effect (reflective) indicators but not when there are causal (formative) indicators, (b) causal (formative) indicators need not have the same consequences, (c) causal (formative) indicators are inherently subject to interpretational confounding, and (d) a researcher cannot detect interpretational confounding when using causal (formative) indicators. This article shows that each claim is false. Rather, interpretational confounding is more a problem of structural misspecification of a model combined with an underidentified model that leaves these misspecifications undetected. Interpretational confounding does not occur if the model is correctly specified whether a researcher has causal (formative) or effect (reflective) indicators. It is the validity of a model not the type of indicator that determines the potential for interpretational confounding. Copyright 2007 APA, all rights reserved.

  1. Analysis Efforts Supporting NSTX Upgrades

    International Nuclear Information System (INIS)

    Zhang, H.; Titus, P.; Rogoff, P.; Zolfaghari, A.; Mangra, D.; Smith, M.

    2010-01-01

    The National Spherical Torus Experiment (NSTX) is a low aspect ratio, spherical torus (ST) configuration device which is located at Princeton Plasma Physics Laboratory (PPPL) This device is presently being updated to enhance its physics by doubling the TF field to 1 Tesla and increasing the plasma current to 2 Mega-amperes. The upgrades include a replacement of the centerstack and addition of a second neutral beam. The upgrade analyses have two missions. The first is to support design of new components, principally the centerstack, the second is to qualify existing NSTX components for higher loads, which will increase by a factor of four. Cost efficiency was a design goal for new equipment qualification, and reanalysis of the existing components. Showing that older components can sustain the increased loads has been a challenging effort in which designs had to be developed that would limit loading on weaker components, and would minimize the extent of modifications needed. Two areas representing this effort have been chosen to describe in more details: analysis of the current distribution in the new TF inner legs, and, second, analysis of the out-of-plane support of the existing TF outer legs.

  2. APS Education and Diversity Efforts

    Science.gov (United States)

    Prestridge, Katherine; Hodapp, Theodore

    2015-11-01

    American Physical Society (APS) has a wide range of education and diversity programs and activities, including programs that improve physics education, increase diversity, provide outreach to the public, and impact public policy. We present the latest programs spearheaded by the Committee on the Status of Women in Physics (CSWP), with highlights from other diversity and education efforts. The CSWP is working to increase the fraction of women in physics, understand and implement solutions for gender-specific issues, enhance professional development opportunities for women in physics, and remedy issues that impact gender inequality in physics. The Conferences for Undergraduate Women in Physics, Professional Skills Development Workshops, and our new Professional Skills program for students and postdocs are all working towards meeting these goals. The CSWP also has site visit and conversation visit programs, where department chairs request that the APS assess the climate for women in their departments or facilitate climate discussions. APS also has two significant programs to increase participation by underrepresented minorities (URM). The newest program, the APS National Mentoring Community, is working to provide mentoring to URM undergraduates, and the APS Bridge Program is an established effort that is dramatically increasing the number of URM PhDs in physics.

  3. Termination of prehospital resuscitative efforts

    DEFF Research Database (Denmark)

    Mikkelsen, Søren; Schaffalitzky de Muckadell, Caroline; Binderup, Lars Grassmé

    2017-01-01

    -and-death decision-making in the patient's medical records is required. We suggest that a template be implemented in the prehospital medical records describing the basis for any ethical decisions. This template should contain information regarding the persons involved in the deliberations and notes on ethical......BACKGROUND: Discussions on ethical aspects of life-and-death decisions within the hospital are often made in plenary. The prehospital physician, however, may be faced with ethical dilemmas in life-and-death decisions when time-critical decisions to initiate or refrain from resuscitative efforts...... need to be taken without the possibility to discuss matters with colleagues. Little is known whether these considerations regarding ethical issues in crucial life-and-death decisions are documented prehospitally. This is a review of the ethical considerations documented in the prehospital medical...

  4. On the biomechanical function of scaffolds for engineering load-bearing soft tissues.

    Science.gov (United States)

    Stella, John A; D'Amore, Antonio; Wagner, William R; Sacks, Michael S

    2010-07-01

    Replacement or regeneration of load-bearing soft tissues has long been the impetus for the development of bioactive materials. While maturing, current efforts continue to be confounded by our lack of understanding of the intricate multi-scale hierarchical arrangements and interactions typically found in native tissues. The current state of the art in biomaterial processing enables a degree of controllable microstructure that can be used for the development of model systems to deduce fundamental biological implications of matrix morphologies on cell function. Furthermore, the development of computational frameworks which allow for the simulation of experimentally derived observations represents a positive departure from what has mostly been an empirically driven field, enabling a deeper understanding of the highly complex biological mechanisms we wish to ultimately emulate. Ongoing research is actively pursuing new materials and processing methods to control material structure down to the micro-scale to sustain or improve cell viability, guide tissue growth, and provide mechanical integrity, all while exhibiting the capacity to degrade in a controlled manner. The purpose of this review is not to focus solely on material processing but to assess the ability of these techniques to produce mechanically sound tissue surrogates, highlight the unique structural characteristics produced in these materials, and discuss how this translates to distinct macroscopic biomechanical behaviors. Copyright 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  5. Adjusting for the Confounding Effects of Treatment Switching—The BREAK-3 Trial: Dabrafenib Versus Dacarbazine

    Science.gov (United States)

    Abrams, Keith R.; Amonkar, Mayur M.; Stapelkamp, Ceilidh; Swann, R. Suzanne

    2015-01-01

    Background. Patients with previously untreated BRAF V600E mutation-positive melanoma in BREAK-3 showed a median overall survival (OS) of 18.2 months for dabrafenib versus 15.6 months for dacarbazine (hazard ratio [HR], 0.76; 95% confidence interval, 0.48–1.21). Because patients receiving dacarbazine were allowed to switch to dabrafenib at disease progression, we attempted to adjust for the confounding effects on OS. Materials and Methods. Rank preserving structural failure time models (RPSFTMs) and the iterative parameter estimation (IPE) algorithm were used. Two analyses, “treatment group” (assumes treatment effect could continue until death) and “on-treatment observed” (assumes treatment effect disappears with discontinuation), were used to test the assumptions around the durability of the treatment effect. Results. A total of 36 of 63 patients (57%) receiving dacarbazine switched to dabrafenib. The adjusted OS HRs ranged from 0.50 to 0.55, depending on the analysis. The RPSFTM and IPE “treatment group” and “on-treatment observed” analyses performed similarly well. Conclusion. RPSFTM and IPE analyses resulted in point estimates for the OS HR that indicate a substantial increase in the treatment effect compared with the unadjusted OS HR of 0.76. The results are uncertain because of the assumptions associated with the adjustment methods. The confidence intervals continued to cross 1.00; thus, the adjusted estimates did not provide statistically significant evidence of a treatment benefit on survival. However, it is clear that a standard intention-to-treat analysis will be confounded in the presence of treatment switching—a reliance on unadjusted analyses could lead to inappropriate practice. Adjustment analyses provide useful additional information on the estimated treatment effects to inform decision making. Implications for Practice: Treatment switching is common in oncology trials, and the implications of this for the interpretation of the

  6. Adjusting for the Confounding Effects of Treatment Switching-The BREAK-3 Trial: Dabrafenib Versus Dacarbazine.

    Science.gov (United States)

    Latimer, Nicholas R; Abrams, Keith R; Amonkar, Mayur M; Stapelkamp, Ceilidh; Swann, R Suzanne

    2015-07-01

    Patients with previously untreated BRAF V600E mutation-positive melanoma in BREAK-3 showed a median overall survival (OS) of 18.2 months for dabrafenib versus 15.6 months for dacarbazine (hazard ratio [HR], 0.76; 95% confidence interval, 0.48-1.21). Because patients receiving dacarbazine were allowed to switch to dabrafenib at disease progression, we attempted to adjust for the confounding effects on OS. Rank preserving structural failure time models (RPSFTMs) and the iterative parameter estimation (IPE) algorithm were used. Two analyses, "treatment group" (assumes treatment effect could continue until death) and "on-treatment observed" (assumes treatment effect disappears with discontinuation), were used to test the assumptions around the durability of the treatment effect. A total of 36 of 63 patients (57%) receiving dacarbazine switched to dabrafenib. The adjusted OS HRs ranged from 0.50 to 0.55, depending on the analysis. The RPSFTM and IPE "treatment group" and "on-treatment observed" analyses performed similarly well. RPSFTM and IPE analyses resulted in point estimates for the OS HR that indicate a substantial increase in the treatment effect compared with the unadjusted OS HR of 0.76. The results are uncertain because of the assumptions associated with the adjustment methods. The confidence intervals continued to cross 1.00; thus, the adjusted estimates did not provide statistically significant evidence of a treatment benefit on survival. However, it is clear that a standard intention-to-treat analysis will be confounded in the presence of treatment switching-a reliance on unadjusted analyses could lead to inappropriate practice. Adjustment analyses provide useful additional information on the estimated treatment effects to inform decision making. Treatment switching is common in oncology trials, and the implications of this for the interpretation of the clinical effectiveness and cost-effectiveness of the novel treatment are important to consider. If

  7. Is the association between general cognitive ability and violent crime caused by family-level confounders?

    Science.gov (United States)

    Frisell, Thomas; Pawitan, Yudi; Långström, Niklas

    2012-01-01

    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. 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. 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. Our results suggest that the association between general cognitive ability and violent criminality is confounded partly by factors shared by brothers. However, most of the association remains even

  8. Is the association between general cognitive ability and violent crime caused by family-level confounders?

    Directory of Open Access Journals (Sweden)

    Thomas Frisell

    Full Text Available 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 factors shared by

  9. [Limitation of the therapeutic effort].

    Science.gov (United States)

    Herreros, B; Palacios, G; Pacho, E

    2012-03-01

    The limitation of the therapeutic effort (LTE) consists in not applying extraordinary or disproportionate measures for therapeutic purposes that are proposed for a patient with poor life prognosis and/or poor quality of life. There are two types. The first is to not initiate certain measures or to withdraw them when they are established. A decision of the LTE should be based on some rigorous criteria, so that we make the following proposal. First, it is necessary to know the most relevant details of the case to make a decision: the preferences of the patient, the preferences of the family when pertinent, the prognosis (severity), the quality of life and distribution of the limited resources. After, the decision should be made. In this phase, participatory deliberation should be established to clarify the end of the intervention. Finally, if it is decided to perform an LTE, it should be decided how to do it. Special procedures, disproportionate measures, that are useless and vain should not be initiated for the therapeutic objective designed (withdraw them if they have been established). When it has been decided to treat a condition (interim measures), the treatment should be maintained. This complex phase may need stratification of he measures. Finally, the necessary palliative measures should be established. Copyright © 2011 Elsevier España, S.L. All rights reserved.

  10. Tissue engineering

    CERN Document Server

    Fisher, John P; Bronzino, Joseph D

    2007-01-01

    Increasingly viewed as the future of medicine, the field of tissue engineering is still in its infancy. As evidenced in both the scientific and popular press, there exists considerable excitement surrounding the strategy of regenerative medicine. To achieve its highest potential, a series of technological advances must be made. Putting the numerous breakthroughs made in this field into a broad context, Tissue Engineering disseminates current thinking on the development of engineered tissues. Divided into three sections, the book covers the fundamentals of tissue engineering, enabling technologies, and tissue engineering applications. It examines the properties of stem cells, primary cells, growth factors, and extracellular matrix as well as their impact on the development of tissue engineered devices. Contributions focus on those strategies typically incorporated into tissue engineered devices or utilized in their development, including scaffolds, nanocomposites, bioreactors, drug delivery systems, and gene t...

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

    Science.gov (United States)

    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

  12. Controlling for unmeasured confounding and spatial misalignment in long-term air pollution and health studies.

    Science.gov (United States)

    Lee, Duncan; Sarran, Christophe

    2015-11-01

    The health impact of long-term exposure to air pollution is now routinely estimated using spatial ecological studies, owing to the recent widespread availability of spatial referenced pollution and disease data. However, this areal unit study design presents a number of statistical challenges, which if ignored have the potential to bias the estimated pollution-health relationship. One such challenge is how to control for the spatial autocorrelation present in the data after accounting for the known covariates, which is caused by unmeasured confounding. A second challenge is how to adjust the functional form of the model to account for the spatial misalignment between the pollution and disease data, which causes within-area variation in the pollution data. These challenges have largely been ignored in existing long-term spatial air pollution and health studies, so here we propose a novel Bayesian hierarchical model that addresses both challenges and provide software to allow others to apply our model to their own data. The effectiveness of the proposed model is compared by simulation against a number of state-of-the-art alternatives proposed in the literature and is then used to estimate the impact of nitrogen dioxide and particulate matter concentrations on respiratory hospital admissions in a new epidemiological study in England in 2010 at the local authority level. © 2015 The Authors. Environmetrics published by John Wiley & Sons Ltd.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    Tuomo T Tompuri

    2015-08-01

    Full Text Available 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.

  16. Compromised Motor Dexterity Confounds Processing Speed Task Outcomes in Stroke Patients

    Directory of Open Access Journals (Sweden)

    Essie Low

    2017-09-01

    Full Text Available Most conventional measures of information processing speed require motor responses to facilitate performance. However, although not often addressed clinically, motor impairment, whether due to age or acquired brain injury, would be expected to confound the outcome measure of such tasks. The current study recruited 29 patients (20 stroke and 9 transient ischemic attack with documented reduction in dexterity of the dominant hand, and 29 controls, to investigate the extent to which 3 commonly used processing speed measures with varying motor demands (a Visuo-Motor Reaction Time task, and the Wechsler Adult Intelligence Scale-IV Symbol Search and Coding subtests may be measuring motor-related speed more so than cognitive speed. Analyses include correlations between indices of cognitive and motor speed obtained from two other tasks (Inspection Time and Pegboard task, respectively with the three speed measures, followed by hierarchical regressions to determine the relative contribution of cognitive and motor speed indices toward task performance. Results revealed that speed outcomes on tasks with relatively high motor demands, such as Coding, were largely reflecting motor speed in individuals with reduced dominant hand dexterity. Thus, findings indicate the importance of employing measures with minimal motor requirements, especially when the assessment of speed is aimed at understanding cognitive rather than physical function.

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

    Science.gov (United States)

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

    2013-01-01

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

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

    Science.gov (United States)

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

    2013-12-01

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

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

    Science.gov (United States)

    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.

  20. Harnessing real world data from wearables and self-monitoring devices: feasibility, confounders and ethical considerations

    Directory of Open Access Journals (Sweden)

    Uttam Barick

    2016-07-01

    Full Text Available The increasing usage of smart phones has compelled mobile technology to become a universal part of everyday life. From wearable gadgets to sophisticated implantable medical devices, the advent of mobile technology has completely transformed the healthcare delivery scenario. Self-report measures enabled by mobile technology are increasingly becoming a more time and cost efficient method of assessing real world health outcomes. But, amidst all the optimism, there are concerns also on adopting this technology as regulations and ethical considerations on privacy legislations of end users are unclear. In general, the healthcare industry functions on some stringent regulations and compliances to ensure the safety and protection of patient information. A couple of the most common regulations are Health Insurance Portability Accountability Act (HIPPA and Health Information Technology for Economic and Clinical Health (HITECH. To harness the true potential of mobile technology to empower stakeholders and provide them a common platform which seamlessly integrates healthcare delivery and research, it is imperative that challenges and drawbacks in the sphere are identified and addressed. In this age of information and technology, no stones should be left unturned to ensure that the human race has access to the best healthcare services without an intrusion into his/her confidentiality. This article is an overview of the role of tracking and self-monitoring devices in data collection for real world evidence/observational studies in context to feasibility, confounders and ethical considerations.

  1. The ad-libitum alcohol 'taste test': secondary analyses of potential confounds and construct validity.

    Science.gov (United States)

    Jones, Andrew; Button, Emily; Rose, Abigail K; Robinson, Eric; Christiansen, Paul; Di Lemma, Lisa; Field, Matt

    2016-03-01

    Motivation to drink alcohol can be measured in the laboratory using an ad-libitum 'taste test', in which participants rate the taste of alcoholic drinks whilst their intake is covertly monitored. Little is known about the construct validity of this paradigm. The objective of this study was to investigate variables that may compromise the validity of this paradigm and its construct validity. We re-analysed data from 12 studies from our laboratory that incorporated an ad-libitum taste test. We considered time of day and participants' awareness of the purpose of the taste test as potential confounding variables. We examined whether gender, typical alcohol consumption, subjective craving, scores on the Alcohol Use Disorders Identification Test and perceived pleasantness of the drinks predicted ad-libitum consumption (construct validity). We included 762 participants (462 female). Participant awareness and time of day were not related to ad-libitum alcohol consumption. Males drank significantly more alcohol than females (p alcohol consumption (p = 0.04), craving (p alcohol consumption. The construct validity of the taste test was supported by relationships between ad-libitum consumption and typical alcohol consumption, craving and pleasantness ratings of the drinks. The ad-libitum taste test is a valid method for the assessment of alcohol intake in the laboratory.

  2. Some confounding factors in the study of mortality and occupational exposures

    International Nuclear Information System (INIS)

    Gilbert, E.S.

    1982-01-01

    With the recent interest in the study of occupational exposures, the impact of certain selective biases in the groups studied is a matter of some concern. In this paper, data from the Hanford nuclear facility population (southeastern Washington State, 1947-1976), which includes many radiation workers, are used to illustrate a method for examining the effect on mortality of such potentially confounding variables as calendar year, length of time since entering the industry, employment status, length of employment, job category, and initial employment year. The analysis, which is based on the Mantel-Haenszel procedure as adapted for a prospective study, differs from most previous studies of occupational variables which have relied primarily on comparing standardized mortality ratios (utilizing an external control) for various subgroups of the population. Results of this analysis confirm other studies in that reduced death rates are observed for early years of follow-up and for those with higher socioeconomic status (as indicated by job category). In addition, workers employed less than two years and especially terminated workers are found to have elevated death rates as compared with the remainder of the study population. It is important that such correlations be taken into account in planning and interpreting analyses of the effects of occupational exposure

  3. Comorbidity and confounding factors in attention-deficit/hyperactivity disorder and sleep disorders in children

    Directory of Open Access Journals (Sweden)

    Huang YS

    2011-09-01

    Full Text Available Ya-Wen Jan1,2, Chien-Ming Yang1,3, Yu-Shu Huang4,51Department of Psychology, National Cheng-Chi University, Taipei; 2Sleep Center of Taipei Medical University Hospital, Taipei; 3The Research Center for Mind Brain and Learning, National Cheng-Chi University, Taipei; 4Department of Child Psychiatry and Sleep Center, Chang Gung Memorial Hospital, Taoyuan; 5College of Medicine, Chang Gung University, Taoyuan, TaiwanAbstract: Sleep problems are commonly reported in children with attention-deficit/hyperactivity disorder (ADHD symptoms. Research data regarding the complex and reciprocal relationship between ADHD and sleep disturbances has now accumulated. This paper is focused on the types of sleep problems that are associated with ADHD symptomatology, and attempts to untangle confounding factors and overlapping symptoms. The goal is also to present an updated overview of the pathophysiology of and treatment strategies for sleep problems in children with ADHD. The review also points out that future research will be needed to clarify further the other psychiatric comorbidities and side effects of medication in order to improve treatment outcomes and prevent misdiagnosis in clinical practice.Keywords: attention-deficit/hyperactivity disorder, sleep, children 

  4. Mental and physical effort affect vigilance differently

    NARCIS (Netherlands)

    Smit, A.S.; Eling, P.A.T.M.; Hopman, M.T.E.; Coenen, A.M.L.

    2005-01-01

    Both physical and mental effort are thought to affect vigilance. Mental effort is known for its vigilance declining effects, but the effects of physical effort are less clear. This study investigated whether these two forms of effort affect the EEG and subjective alertness differently. Participants

  5. Mental and physical effort affect vigilance differently.

    NARCIS (Netherlands)

    Smit, A.S.; Eling, P.A.T.M.; Hopman, M.T.E.; Coenen, A.M.L.

    2005-01-01

    Both physical and mental effort are thought to affect vigilance. Mental effort is known for its vigilance declining effects, but the effects of physical effort are less clear. This study investigated whether these two forms of effort affect the EEG and subjective alertness differently. Participants

  6. Artificial light at night confounds broad-scale habitat use by migrating birds

    NARCIS (Netherlands)

    McLaren, J.D.; Buler, J.J.; Schreckengost, T.; Smolinsky, J.A.; Boone, M.; van Loon, E.E.; Dawson, D.K.; Walters, E.L.

    With many of the world's migratory bird populations in alarming decline, broad-scale assessments of responses to migratory hazards may prove crucial to successful conservation efforts. Most birds migrate at night through increasingly light-polluted skies. Bright light sources can attract airborne

  7. Tissue Engineering of the Penis

    Directory of Open Access Journals (Sweden)

    Manish N. Patel

    2011-01-01

    Full Text Available Congenital disorders, cancer, trauma, or other conditions of the genitourinary tract can lead to significant organ damage or loss of function, necessitating eventual reconstruction or replacement of the damaged structures. However, current reconstructive techniques are limited by issues of tissue availability and compatibility. Physicians and scientists have begun to explore tissue engineering and regenerative medicine strategies for repair and reconstruction of the genitourinary tract. Tissue engineering allows the development of biological substitutes which could potentially restore normal function. Tissue engineering efforts designed to treat or replace most organs are currently being undertaken. Most of these efforts have occurred within the past decade. However, before these engineering techniques can be applied to humans, further studies are needed to ensure the safety and efficacy of these new materials. Recent progress suggests that engineered urologic tissues and cell therapy may soon have clinical applicability.

  8. External adjustment of unmeasured confounders in a case-control study of benzodiazepine use and cancer risk

    DEFF Research Database (Denmark)

    Thygesen, Lau Caspar; Pottegård, Anton; Ersbøll, Annette Kjaer

    2017-01-01

    AIMS: Previous studies have reported diverging results on the association between benzodiazepine use and cancer risk. METHODS: We investigated this association in a matched case-control study including incident cancer cases during 2002-2009 in the Danish Cancer Registry (n = 94 923) and age......% confidence interval 1.00-1.19) and for smoking-related cancers from 1.20 to 1.10 (95% confidence interval 1.00-1.21). CONCLUSION: We conclude that the increased risk observed in the solely register-based study could partly be attributed to unmeasured confounding....... PSs were used: The error-prone PS using register-based confounders and the calibrated PS based on both register- and survey-based confounders, retrieved from the Health Interview Survey. RESULTS: Register-based data showed that cancer cases had more diagnoses, higher comorbidity score and more co...

  9. Translational Rodent Models for Research on Parasitic Protozoa-A Review of Confounders and Possibilities.

    Science.gov (United States)

    Ehret, Totta; Torelli, Francesca; Klotz, Christian; Pedersen, Amy B; Seeber, Frank

    2017-01-01

    Rodents, in particular Mus musculus , have a long and invaluable history as models for human diseases in biomedical research, although their translational value has been challenged in a number of cases. We provide some examples in which rodents have been suboptimal as models for human biology and discuss confounders which influence experiments and may explain some of the misleading results. Infections of rodents with protozoan parasites are no exception in requiring close consideration upon model choice. We focus on the significant differences between inbred, outbred and wild animals, and the importance of factors such as microbiota, which are gaining attention as crucial variables in infection experiments. Frequently, mouse or rat models are chosen for convenience, e.g., availability in the institution rather than on an unbiased evaluation of whether they provide the answer to a given question. Apart from a general discussion on translational success or failure, we provide examples where infections with single-celled parasites in a chosen lab rodent gave contradictory or misleading results, and when possible discuss the reason for this. We present emerging alternatives to traditional rodent models, such as humanized mice and organoid primary cell cultures. So-called recombinant inbred strains such as the Collaborative Cross collection are also a potential solution for certain challenges. In addition, we emphasize the advantages of using wild rodents for certain immunological, ecological, and/or behavioral questions. The experimental challenges (e.g., availability of species-specific reagents) that come with the use of such non-model systems are also discussed. Our intention is to foster critical judgment of both traditional and newly available translational rodent models for research on parasitic protozoa that can complement the existing mouse and rat models.

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

    Directory of Open Access Journals (Sweden)

    Mike S Fowler

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

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

    Directory of Open Access Journals (Sweden)

    R. F. Wright

    2001-01-01

    Full Text Available 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. Keywords: acid deposition, global change, water, soil, catchment, experiment, Norway.

  12. Marked EEG worsening following Levetiracetam overdose: How a pharmacological issue can confound coma prognosis.

    Science.gov (United States)

    Bouchier, Baptiste; Demarquay, Geneviève; Guérin, Claude; André-Obadia, Nathalie; Gobert, Florent

    2017-01-01

    Levetiracetam is an anti-epileptic drug commonly used in intensive care when seizure is suspected as a possible cause of coma. We propose to question the cofounding effect of Levetiracetam during the prognostication process in a case of anoxic coma. We report the story of a young woman presenting a comatose state following a hypoxic cardiac arrest. After a first EEG presenting an intermediate EEG pattern, a seizure suspicion led to prescribe Levetiracetam. The EEG showed then the appearance of burst suppression, which was compatible with a very severe pattern of post-anoxic coma. This aggravation was in fact related to an overdose of Levetiracetam (the only medication introduced recently) and was reversible after Levetiracetam cessation. The increased plasmatic dosages of Levetiracetam confirming this overdose could have been favoured by a moderate reduction of renal clearance, previously underestimated because of a low body-weight. This EEG dynamic was unexpected under Levetiracetam and could sign a functional instability after anoxia. Burst suppression is classically observed with high doses of anaesthetics, but is not expected after a minor anti-epileptic drug. This report proposes that Levetiracetam tolerance might not be straightforward after brain lesions and engages us to avoid confounding factors during the awakening prognostication, which is mainly based on the severity of the EEG. Hence, prognosis should not be decided on an isolated parameter, especially if the dynamic is atypical after a new prescription, even for well-known drugs. For any suspicion, the drug's dosage and replacement should be managed before any premature care's withdrawal. Copyright © 2016 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

    Fowler, Mike S; Ruokolainen, Lasse

    2013-01-01

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

  14. Serotonin-1A receptors in major depression quantified using PET: controversies, confounds, and recommendations.

    Science.gov (United States)

    Shrestha, Saurav; Hirvonen, Jussi; Hines, Christina S; Henter, Ioline D; Svenningsson, Per; Pike, Victor W; Innis, Robert B

    2012-02-15

    The serotonin-1A (5-HT(1A)) receptor is of particular interest in human positron emission tomography (PET) studies of major depressive disorder (MDD). Of the eight studies investigating this issue in the brains of patients with MDD, four reported decreased 5-HT(1A) receptor density, two reported no change, and two reported increased 5-HT(1A) receptor density. While clinical heterogeneity may have contributed to these differing results, methodological factors by themselves could also explain the discrepancies. This review highlights several of these factors, including the use of the cerebellum as a reference region and the imprecision of measuring the concentration of parent radioligand in arterial plasma, the method otherwise considered to be the 'gold standard'. Other potential confounds also exist that could restrict or unexpectedly affect the interpretation of results. For example, the radioligand may be a substrate for an efflux transporter - like P-gp - at the blood-brain barrier; furthermore, the binding of the radioligand to the receptor in various stages of cellular trafficking is unknown. Efflux transport and cellular trafficking may also be differentially expressed in patients compared to healthy subjects. We believe that, taken together, the existing disparate findings do not reliably answer the question of whether 5-HT(1A) receptors are altered in MDD or in subgroups of patients with MDD. In addition, useful meta-analysis is precluded because only one of the imaging centers acquired all the data necessary to address these methodological concerns. We recommend that in the future, individual centers acquire more thorough data capable of addressing methodological concerns, and that multiple centers collaborate to meaningfully pool their data for meta-analysis. Published by Elsevier Inc.

  15. Translational Rodent Models for Research on Parasitic Protozoa—A Review of Confounders and Possibilities

    Directory of Open Access Journals (Sweden)

    Totta Ehret

    2017-06-01

    Full Text Available Rodents, in particular Mus musculus, have a long and invaluable history as models for human diseases in biomedical research, although their translational value has been challenged in a number of cases. We provide some examples in which rodents have been suboptimal as models for human biology and discuss confounders which influence experiments and may explain some of the misleading results. Infections of rodents with protozoan parasites are no exception in requiring close consideration upon model choice. We focus on the significant differences between inbred, outbred and wild animals, and the importance of factors such as microbiota, which are gaining attention as crucial variables in infection experiments. Frequently, mouse or rat models are chosen for convenience, e.g., availability in the institution rather than on an unbiased evaluation of whether they provide the answer to a given question. Apart from a general discussion on translational success or failure, we provide examples where infections with single-celled parasites in a chosen lab rodent gave contradictory or misleading results, and when possible discuss the reason for this. We present emerging alternatives to traditional rodent models, such as humanized mice and organoid primary cell cultures. So-called recombinant inbred strains such as the Collaborative Cross collection are also a potential solution for certain challenges. In addition, we emphasize the advantages of using wild rodents for certain immunological, ecological, and/or behavioral questions. The experimental challenges (e.g., availability of species-specific reagents that come with the use of such non-model systems are also discussed. Our intention is to foster critical judgment of both traditional and newly available translational rodent models for research on parasitic protozoa that can complement the existing mouse and rat models.

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

    Science.gov (United States)

    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. © 2015 Wiley Periodicals, Inc.

  17. Tissue types (image)

    Science.gov (United States)

    ... are 4 basic types of tissue: connective tissue, epithelial tissue, muscle tissue, and nervous tissue. Connective tissue supports ... binds them together (bone, blood, and lymph tissues). Epithelial tissue provides a covering (skin, the linings of the ...

  18. When can efforts to control nuisance and invasive species backfire?

    Science.gov (United States)

    Zipkin, Elise F; Kraft, Clifford E; Cooch, Evan G; Sullivan, Patrick J

    2009-09-01

    Population control through harvest has the potential to reduce the abundance of nuisance and invasive species. However, demographic structure and density-dependent processes can confound removal efforts and lead to undesirable consequences, such as overcompensation (an increase in abundance in response to harvest) and instability (population cycling or chaos). Recent empirical studies have demonstrated the potential for increased mortality (such as that caused by harvest) to lead to overcompensation and instability in plant, insect, and fish populations. We developed a general population model with juvenile and adult stages to help determine the conditions under which control harvest efforts can produce unintended outcomes. Analytical and simulation analyses of the model demonstrated that the potential for overcompensation as a result of harvest was significant for species with high fecundity, even when annual stage-specific survivorship values were fairly low. Population instability as a result of harvest occurred less frequently and was only possible with harvest strategies that targeted adults when both fecundity and adult survivorship were high. We considered these results in conjunction with current literature on nuisance and invasive species to propose general guidelines for assessing the risks associated with control harvest based on life history characteristics of target populations. Our results suggest that species with high per capita fecundity (over discrete breeding periods), short juvenile stages, and fairly constant survivorship rates are most likely to respond undesirably to harvest. It is difficult to determine the extent to which overcompensation and instability could occur during real-world removal efforts, and more empirical removal studies should be undertaken to evaluate population-level responses to control harvests. Nevertheless, our results identify key issues that have been seldom acknowledged and are potentially generic across taxa.

  19. Modelling Cardiac Signal as a Confound in EEG-fMRI and its Application in Focal Epilepsy

    DEFF Research Database (Denmark)

    Liston, Adam David; Salek-Haddadi, Afraim; Hamandi, Khalid

    2005-01-01

    Cardiac noise has been shown to reduce the sensitivity of functional Magnetic Resonance Imaging (fMRI) to an experimental effect due to its confounding presence in the blood oxygenation level-dependent (BOLD) signal. Its effect is most severe in particular regions of the brain and a method is yet...

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

    Science.gov (United States)

    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…

  1. Associations between lifestyle and air pollution exposure: Potential for confounding in large administrative data cohorts.

    Science.gov (United States)

    Strak, Maciej; Janssen, Nicole; Beelen, Rob; Schmitz, Oliver; Karssenberg, Derek; Houthuijs, Danny; van den Brink, Carolien; Dijst, Martin; Brunekreef, Bert; Hoek, Gerard

    2017-07-01

    Cohorts based on administrative data have size advantages over individual cohorts in investigating air pollution risks, but often lack in-depth information on individual risk factors related to lifestyle. If there is a correlation between lifestyle and air pollution, omitted lifestyle variables may result in biased air pollution risk estimates. Correlations between lifestyle and air pollution can be induced by socio-economic status affecting both lifestyle and air pollution exposure. Our overall aim was to assess potential confounding by missing lifestyle factors on air pollution mortality risk estimates. The first aim was to assess associations between long-term exposure to several air pollutants and lifestyle factors. The second aim was to assess whether these associations were sensitive to adjustment for individual and area-level socioeconomic status (SES), and whether they differed between subgroups of the population. Using the obtained air pollution-lifestyle associations and indirect adjustment methods, our third aim was to investigate the potential bias due to missing lifestyle information on air pollution mortality risk estimates in administrative cohorts. We used a recent Dutch national health survey of 387,195 adults to investigate the associations of PM 10 , PM 2.5 , PM 2.5-10 , PM 2.5 absorbance, OP DTT, OP ESR and NO 2 annual average concentrations at the residential address from land use regression models with individual smoking habits, alcohol consumption, physical activity and body mass index. We assessed the associations with and without adjustment for neighborhood and individual SES characteristics typically available in administrative data cohorts. We illustrated the effect of including lifestyle information on the air pollution mortality risk estimates in administrative cohort studies using a published indirect adjustment method. Current smoking and alcohol consumption were generally positively associated with air pollution. Physical activity

  2. Measuring collections effort improves cash performance.

    Science.gov (United States)

    Shutts, Joe

    2009-09-01

    Having a satisfied work force can lead to an improved collections effort. Hiring the right people and training them ensures employee engagement. Measuring collections effort and offering incentives is key to revenue cycle success.

  3. Controlling confounding by frailty when estimating influenza vaccine effectiveness using predictors of dependency in activities of daily living.

    Science.gov (United States)

    Zhang, Henry T; McGrath, Leah J; Wyss, Richard; Ellis, Alan R; Stürmer, Til

    2017-12-01

    To improve control of confounding by frailty when estimating the effect of influenza vaccination on all-cause mortality by controlling for a published set of claims-based predictors of dependency in activities of daily living (ADL). Using Medicare claims data, a cohort of beneficiaries >65 years of age was followed from September 1, 2007, to April 12, 2008, with covariates assessed in the 6 months before follow-up. We estimated Cox proportional hazards models of all-cause mortality, with influenza vaccination as a time-varying exposure. We controlled for common demographics, comorbidities, and health care utilization variables and then added 20 ADL dependency predictors. To gauge residual confounding, we estimated pre-influenza season hazard ratios (HRs) between September 1, 2007 and January 5, 2008, which should be 1.0 in the absence of bias. A cohort of 2 235 140 beneficiaries was created, with a median follow-up of 224 days. Overall, 52% were vaccinated and 4% died during follow-up. During the pre-influenza season period, controlling for demographics, comorbidities, and health care use resulted in a HR of 0.66 (0.64, 0.67). Adding the ADL dependency predictors moved the HR to 0.68 (0.67, 0.70). Controlling for demographics and ADL dependency predictors alone resulted in a HR of 0.68 (0.66, 0.70). Results were consistent with those in the literature, with significant uncontrolled confounding after adjustment for demographics, comorbidities, and health care use. Adding ADL dependency predictors moved HRs slightly closer to the null. Of the comorbidities, health care use variables, and ADL dependency predictors, the last set reduced confounding most. However, substantial uncontrolled confounding remained. Copyright © 2017 John Wiley & Sons, Ltd.

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

    International Nuclear Information System (INIS)

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

    2012-01-01

    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.

  5. Tissue Classification

    DEFF Research Database (Denmark)

    Van Leemput, Koen; Puonti, Oula

    2015-01-01

    Computational methods for automatically segmenting magnetic resonance images of the brain have seen tremendous advances in recent years. So-called tissue classification techniques, aimed at extracting the three main brain tissue classes (white matter, gray matter, and cerebrospinal fluid), are now...... well established. In their simplest form, these methods classify voxels independently based on their intensity alone, although much more sophisticated models are typically used in practice. This article aims to give an overview of often-used computational techniques for brain tissue classification...

  6. Zika virus produces noncoding RNAs using a multi-pseudoknot structure that confounds a cellular exonuclease

    International Nuclear Information System (INIS)

    Akiyama, Benjamin M.; Laurence, Hannah M.; University of Colorado, Aurora, CO; University of California, Davis, CA; Massey, Aaron R.

    2016-01-01

    The outbreak of Zika virus (ZIKV) and associated fetal microcephaly mandates efforts to understand the molecular processes of infection. Related flaviviruses produce noncoding subgenomic flaviviral RNAs (sfRNAs) that are linked to pathogenicity in fetal mice. These viruses make sfRNAs by co-opting a cellular exonuclease via structured RNAs called xrRNAs. We found that ZIKV-infected monkey and human epithelial cells, mouse neurons, and mosquito cells produce sfRNAs. The RNA structure that is responsible for ZIKV sfRNA production forms a complex fold that is likely found in many pathogenic flaviviruses. Mutations that disrupt the structure affect exonuclease resistance in vitro and sfRNA formation during infection. The complete ZIKV xrRNA structure clarifies the mechanism of exonuclease resistance and identifies features that may modulate function in diverse flaviviruses.

  7. Artificial light at night confounds broad-scale habitat use by migrating birds

    Science.gov (United States)

    McLaren, James D.; Buler, Jeffrey J.; Schreckengost, Tim; Smolinsky, Jaclyn A.; Boone, Matthew; van Loon, E. Emiel; Dawson, Deanna K.; Walters, Eric L.

    2018-01-01

    With many of the world's migratory bird populations in alarming decline, broad-scale assessments of responses to migratory hazards may prove crucial to successful conservation efforts. Most birds migrate at night through increasingly light-polluted skies. Bright light sources can attract airborne migrants and lead to collisions with structures, but might also influence selection of migratory stopover habitat and thereby acquisition of food resources. We demonstrate, using multi-year weather radar measurements of nocturnal migrants across the northeastern U.S., that autumnal migrant stopover density increased at regional scales with proximity to the brightest areas, but decreased within a few kilometers of brightly-lit sources. This finding implies broad-scale attraction to artificial light while airborne, impeding selection for extensive forest habitat. Given that high-quality stopover habitat is critical to successful migration, and hindrances during migration can decrease fitness, artificial lights present a potentially heightened conservation concern for migratory bird populations.

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

    Science.gov (United States)

    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.

  9. Salivary alpha-amylase: More than an enzyme Investigating confounders of stress-induced and basal amylase activity

    OpenAIRE

    Strahler, Jana

    2010-01-01

    Summary: Salivary alpha-amylase: More than an enzyme - Investigating confounders of stress-induced and basal amylase activity (Dipl.-Psych. Jana Strahler) The hypothalamus-pituitary-adrenal (HPA) axis and the autonomic nervous system (ANS) are two of the major systems playing a role in the adaptation of organisms to developmental changes that threaten homeostasis. The HPA system involves the secretion of glucocorticoids, including cortisol, into the circulatory system. Numerous studies hav...

  10. The impact of bilinguism on cognitive aging and dementia:Finding a path through a forest of confounding variables

    OpenAIRE

    Bak, Thomas

    2016-01-01

    Within the current debates on cognitive reserve, cognitive aging and dementia, showing increasingly a positive effect of mental, social and physical activities on health in older age, bilingualism remains one of the most controversial issues. Some reasons for it might be social or even ideological. However, one of the most important genuine problems facing bilingualism research is the high number of potential confounding variables. Bilingual communities often differ from monolingual ones in a...

  11. Pocket money and child effort at school

    OpenAIRE

    François-Charles Wolff; Christine Barnet-Verzat

    2008-01-01

    In this paper, we study the relationship between the provision of parental pocket and the level of effort undertaken by the child at school. Under altruism, an increased amount of parental transfer should reduce the child's effort. Our empirical analysis is based on a French data set including about 1,400 parent-child pairs. We find that children do not undertake less effort when their parents are more generous.

  12. 'Mechanical restraint-confounders, risk, alliance score': testing the clinical validity of a new risk assessment instrument.

    Science.gov (United States)

    Deichmann Nielsen, Lea; Bech, Per; Hounsgaard, Lise; Alkier Gildberg, Frederik

    2017-08-01

    Unstructured risk assessment, as well as confounders (underlying reasons for the patient's risk behaviour and alliance), risk behaviour, and parameters of alliance, have been identified as factors that prolong the duration of mechanical restraint among forensic mental health inpatients. To clinically validate a new, structured short-term risk assessment instrument called the Mechanical Restraint-Confounders, Risk, Alliance Score (MR-CRAS), with the intended purpose of supporting the clinicians' observation and assessment of the patient's readiness to be released from mechanical restraint. The content and layout of MR-CRAS and its user manual were evaluated using face validation by forensic mental health clinicians, content validation by an expert panel, and pilot testing within two, closed forensic mental health inpatient units. The three sub-scales (Confounders, Risk, and a parameter of Alliance) showed excellent content validity. The clinical validations also showed that MR-CRAS was perceived and experienced as a comprehensible, relevant, comprehensive, and useable risk assessment instrument. MR-CRAS contains 18 clinically valid items, and the instrument can be used to support the clinical decision-making regarding the possibility of releasing the patient from mechanical restraint. The present three studies have clinically validated a short MR-CRAS scale that is currently being psychometrically tested in a larger study.

  13. On Estimation of the Survivor Average Causal Effect in Observational Studies when Important Confounders are Missing Due to Death

    Science.gov (United States)

    Egleston, Brian L.; Scharfstein, Daniel O.; MacKenzie, Ellen

    2008-01-01

    We focus on estimation of the causal effect of treatment on the functional status of individuals at a fixed point in time t* after they have experienced a catastrophic event, from observational data with the following features: (1) treatment is imposed shortly after the event and is non-randomized, (2) individuals who survive to t* are scheduled to be interviewed, (3) there is interview non-response, (4) individuals who die prior to t* are missing information on pre-event confounders, (5) medical records are abstracted on all individuals to obtain information on post-event, pre-treatment confounding factors. To address the issue of survivor bias, we seek to estimate the survivor average causal effect (SACE), the effect of treatment on functional status among the cohort of individuals who would survive to t* regardless of whether or not assigned to treatment. To estimate this effect from observational data, we need to impose untestable assumptions, which depend on the collection of all confounding factors. Since pre-event information is missing on those who die prior to t*, it is unlikely that these data are missing at random (MAR). We introduce a sensitivity analysis methodology to evaluate the robustness of SACE inferences to deviations from the MAR assumption. We apply our methodology to the evaluation of the effect of trauma center care on vitality outcomes using data from the National Study on Costs and Outcomes of Trauma Care. PMID:18759833

  14. Incentive Design and Mis-Allocated Effort

    OpenAIRE

    Schnedler, Wendelin

    2013-01-01

    Incentives often distort behavior: they induce agents to exert effort but this effort is not employed optimally. This paper proposes a theory of incentive design allowing for such distorted behavior. At the heart of the theory is a trade-off between getting the agent to exert effort and ensuring that this effort is used well. The theory covers various moral-hazard models, ranging from traditional single-task to multi-task models. It also provides -for the first time- a formalization and proof...

  15. Updating the mitochondrial free radical theory of aging: an integrated view, key aspects, and confounding concepts.

    Science.gov (United States)

    Barja, Gustavo

    2013-10-20

    An updated version of the mitochondrial free radical theory of aging (MFRTA) and longevity is reviewed. Key aspects of the theory are emphasized. Another main focus concerns common misconceptions that can mislead investigators from other specialties, even to wrongly discard the theory. Those different issues include (i) the main reactive oxygen species (ROS)-generating site in the respiratory chain in relation to aging and longevity: complex I; (ii) the close vicinity or even contact between that site and the mitochondrial DNA, in relation to the lack of local efficacy of antioxidants and to sub-cellular compartmentation; (iii) the relationship between mitochondrial ROS production and oxygen consumption; (iv) recent criticisms on the MFRTA; (v) the widespread assumption that ROS are simple "by-products" of the mitochondrial respiratory chain; (vi) the unnecessary postulation of "vicious cycle" hypotheses of mitochondrial ROS generation which are not central to the free radical theory of aging; and (vii) the role of DNA repair concerning endogenous versus exogenous damage. After considering the large body of data already available, two general characteristics responsible for the high maintenance degree of long-lived animals emerge: (i) a low generation rate of endogenous damage: and (ii) the possession of tissue macromolecules that are highly resistant to oxidative modification.

  16. Infiltrating leukocytes confound the detection of E-cadherin promoter methylation in tumors

    International Nuclear Information System (INIS)

    Lombaerts, Marcel; Middeldorp, Janneke W.; Weide, Esther van der; Philippo, Katja; Wezel, Tom van; Smit, Vincent T.H.B.M.; Cornelisse, Cees J.; Cleton-Jansen, Anne-Marie

    2004-01-01

    Promoter hypermethylation is known to result in transcriptional downregulation of many genes including the CDH1 gene. In this study we set out to determine CDH1 promoter methylation in breast tumors with decreased or absent E-cadherin protein expression and without CDH1 gene mutations by methylation-specific PCR (MSP). Interestingly, some tumor samples with normal E-cadherin expression yielded a methylation-specific PCR product. We hypothesized that other cells than tumor cells contribute to these products. Since in normal breast tissue no CDH1 promoter methylation is detected, infiltrating leukocytes, often present in tumors, might account for these methylation-specific fragments. Indeed, a methylation-specific fragment is found in all twelve leukocyte samples tested. Furthermore, activated T-cells also yielded a methylation-specific fragment. Sequencing of these fragments reveals two distinct methylation profiles. Leukocytes have only partial methylation of some CpGs, while the tumor-associated methylation profile shows complete methylation of most CpGs. Therefore, to assess whether CDH1 methylation is tumor associated, sequencing of MSP products is a prerequisite. Here we show that out of six lobular tumors lacking E-cadherin protein expression, three have tumor-associated CDH1 promoter methylation while in three other tumors no methylation is detected

  17. Time preferences, study effort, and academic performance

    NARCIS (Netherlands)

    Non, J.A.; Tempelaar, D.T.

    2014-01-01

    We analyze the relation between time preferences, study effort, and academic performance among first-year Business and Economics students. Time preferences are measured by stated preferences for an immediate payment over larger delayed payments. Data on study efforts are derived from an electronic

  18. Interests, Effort, Achievement and Vocational Preference.

    Science.gov (United States)

    Sjoberg, L.

    1984-01-01

    Relationships between interest in natural sciences and technology and perceived ability, success, and invested effort were studied in Swedish secondary school students. Interests were accounted for by logical orientation and practical value. Interests and grades were strongly correlated, but correlations between interests and effort and vocational…

  19. Dopamine and Effort-Based Decision Making

    Directory of Open Access Journals (Sweden)

    Irma Triasih Kurniawan

    2011-06-01

    Full Text Available Motivational theories of choice focus on the influence of goal values and strength of reinforcement to explain behavior. By contrast relatively little is known concerning how the cost of an action, such as effort expended, contributes to a decision to act. Effort-based decision making addresses how we make an action choice based on an integration of action and goal values. Here we review behavioral and neurobiological data regarding the representation of effort as action cost, and how this impacts on decision making. Although organisms expend effort to obtain a desired reward there is a striking sensitivity to the amount of effort required, such that the net preference for an action decreases as effort cost increases. We discuss the contribution of the neurotransmitter dopamine (DA towards overcoming response costs and in enhancing an animal’s motivation towards effortful actions. We also consider the contribution of brain structures, including the basal ganglia (BG and anterior cingulate cortex (ACC, in the internal generation of action involving a translation of reward expectation into effortful action.

  20. Listening Effort With Cochlear Implant Simulations

    NARCIS (Netherlands)

    Pals, Carina; Sarampalis, Anastasios; Başkent, Deniz

    2013-01-01

    Purpose: Fitting a cochlear implant (CI) for optimal speech perception does not necessarily optimize listening effort. This study aimed to show that listening effort may change between CI processing conditions for which speech intelligibility remains constant. Method: Nineteen normal-hearing

  1. Effort and Selection Effects of Incentive Contracts

    NARCIS (Netherlands)

    Bouwens, J.F.M.G.; van Lent, L.A.G.M.

    2003-01-01

    We show that the improved effort of employees associated with incentive contracts depends on the properties of the performance measures used in the contract.We also find that the power of incentives in the contract is only indirectly related to any improved employee effort.High powered incentive

  2. The Effect of Age on Listening Effort

    Science.gov (United States)

    Degeest, Sofie; Keppler, Hannah; Corthals, Paul

    2015-01-01

    Purpose: The objective of this study was to investigate the effect of age on listening effort. Method: A dual-task paradigm was used to evaluate listening effort in different conditions of background noise. Sixty adults ranging in age from 20 to 77 years were included. A primary speech-recognition task and a secondary memory task were performed…

  3. Adiposity signals predict vocal effort in Alston's singing mice.

    Science.gov (United States)

    Burkhard, Tracy T; Westwick, Rebecca R; Phelps, Steven M

    2018-04-25

    Advertisement displays often seem extravagant and expensive, and are thought to depend on the body condition of a signaller. Nevertheless, we know little about how signallers adjust effort based on condition, and few studies find a strong relationship between natural variation in condition and display. To examine the relationship between body condition and signal elaboration more fully, we characterized physiological condition and acoustic displays in a wild rodent with elaborate vocalizations, Alston's singing mouse, Scotinomys teguina We found two major axes of variation in condition-one defined by short-term fluctuations in caloric nutrients, and a second by longer-term variation in adiposity. Among acoustic parameters, song effort was characterized by high rates of display and longer songs. Song effort was highly correlated with measures of adiposity. We found that leptin was a particularly strong predictor of display effort. Leptin is known to influence investment in other costly traits, such as immune function and reproduction. Plasma hormone levels convey somatic state to a variety of tissues, and may govern trait investment across vertebrates. Such measures offer new insights into how animals translate body condition into behavioural and life-history decisions. © 2018 The Author(s).

  4. Low-effort thought promotes political conservatism.

    Science.gov (United States)

    Eidelman, Scott; Crandall, Christian S; Goodman, Jeffrey A; Blanchar, John C

    2012-06-01

    The authors test the hypothesis that low-effort thought promotes political conservatism. In Study 1, alcohol intoxication was measured among bar patrons; as blood alcohol level increased, so did political conservatism (controlling for sex, education, and political identification). In Study 2, participants under cognitive load reported more conservative attitudes than their no-load counterparts. In Study 3, time pressure increased participants' endorsement of conservative terms. In Study 4, participants considering political terms in a cursory manner endorsed conservative terms more than those asked to cogitate; an indicator of effortful thought (recognition memory) partially mediated the relationship between processing effort and conservatism. Together these data suggest that political conservatism may be a process consequence of low-effort thought; when effortful, deliberate thought is disengaged, endorsement of conservative ideology increases.

  5. Time-Dependent Confounding in the Study of the Effects of Regular Physical Activity in Chronic Obstructive Pulmonary Disease: An Application of the Marginal Structural Model

    DEFF Research Database (Denmark)

    Garcia-Aymerich, J.; Lange, P.; Serra, I.

    2008-01-01

    this type of confounding. We sought to assess the presence of time-dependent confounding in the association between physical activity and COPD development and course by comparing risk estimates between standard statistical methods and MSMs. METHODS: By using the population-based cohort Copenhagen City Heart...

  6. Visual cues and listening effort: individual variability.

    Science.gov (United States)

    Picou, Erin M; Ricketts, Todd A; Hornsby, Benjamin W Y

    2011-10-01

    To investigate the effect of visual cues on listening effort as well as whether predictive variables such as working memory capacity (WMC) and lipreading ability affect the magnitude of listening effort. Twenty participants with normal hearing were tested using a paired-associates recall task in 2 conditions (quiet and noise) and 2 presentation modalities (audio only [AO] and auditory-visual [AV]). Signal-to-noise ratios were adjusted to provide matched speech recognition across audio-only and AV noise conditions. Also measured were subjective perceptions of listening effort and 2 predictive variables: (a) lipreading ability and (b) WMC. Objective and subjective results indicated that listening effort increased in the presence of noise, but on average the addition of visual cues did not significantly affect the magnitude of listening effort. Although there was substantial individual variability, on average participants who were better lipreaders or had larger WMCs demonstrated reduced listening effort in noise in AV conditions. Overall, the results support the hypothesis that integrating auditory and visual cues requires cognitive resources in some participants. The data indicate that low lipreading ability or low WMC is associated with relatively effortful integration of auditory and visual information in noise.

  7. Programming effort analysis of the ELLPACK language

    Science.gov (United States)

    Rice, J. R.

    1978-01-01

    ELLPACK is a problem statement language and system for elliptic partial differential equations which is implemented by a FORTRAN preprocessor. ELLPACK's principal purpose is as a tool for the performance evaluation of software. However, it is used here as an example with which to study the programming effort required for problem solving. It is obvious that problem statement languages can reduce programming effort tremendously; the goal is to quantify this somewhat. This is done by analyzing the lengths and effort (as measured by Halstead's software science technique) of various approaches to solving these problems.

  8. Examination of the Relationship between Oral Health and Arterial Sclerosis without Genetic Confounding through the Study of Older Japanese Twins.

    Directory of Open Access Journals (Sweden)

    Yuko Kurushima

    Full Text Available Although researchers have recently demonstrated a relationship between oral health and arterial sclerosis, the genetic contribution to this relationship has been ignored even though genetic factors are expected to have some effect on various diseases. The aim of this study was to evaluate oral health as a significant risk factor related to arterial sclerosis after eliminating genetic confounding through study of older Japanese twins.Medical and dental surveys were conducted individually for 106 Japanese twin pairs over the age of 50 years. Maximal carotid intima-media thickness (IMT-Cmax was measured as a surrogate marker of arterial sclerosis. IMT-Cmax > 1.0 mm was diagnosed as arterial sclerosis. All of the twins were examined for the number of remaining teeth, masticatory performance, and periodontal status. We evaluated each measurement related with IMT-Cmax and arterial sclerosis using generalized estimating equations analysis adjusted for potential risk factors. For non-smoking monozygotic twins, a regression analysis using a "between within" model was conducted to evaluate the relationship between IMT-Cmax and the number of teeth as the environmental factor controlling genetic and familial confounding.We examined 91 monozygotic and 15 dizygotic twin pairs (males: 42, females: 64 with a mean (± standard deviation age of 67.4 ± 10.0 years. Out of all of the oral health-related measurements collected, only the number of teeth was significantly related to arterial sclerosis (odds ratio: 0.72, 95% confidence interval: 0.52-0.99 per five teeth. Regression analysis showed a significant association between the IMT-Cmax and the number of teeth as an environmental factor (p = 0.037.Analysis of monozygotic twins older than 50 years of age showed that having fewer teeth could be a significant environmental factor related to arterial sclerosis, even after controlling for genetic and familial confounding.

  9. Control selection and confounding factors: A lesson from a Japanese case-control study to examine acellular pertussis vaccine effectiveness.

    Science.gov (United States)

    Ohfuji, Satoko; Okada, Kenji; Nakano, Takashi; Ito, Hiroaki; Hara, Megumi; Kuroki, Haruo; Hirota, Yoshio

    2017-08-24

    When using a case-control study design to examine vaccine effectiveness, both the selection of control subjects and the consideration of potential confounders must be the important issues to ensure accurate results. In this report, we described our experience from a case-control study conducted to evaluate the effectiveness of acellular pertussis vaccine combined with diphtheria-tetanus toxoids (DTaP vaccine). Newly diagnosed pertussis cases and age- and sex-matched friend-controls were enrolled, and the history of DTaP vaccination was compared between groups. Logistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) of vaccination for development of pertussis. After adjustment for potential confounders, four doses of DTaP vaccination showed a lower OR for pediatrician-diagnosed pertussis (OR=0.11, 95% CI, 0.01-0.99). In addition, the decreasing OR of four doses vaccination was more pronounced for laboratory-confirmed pertussis (OR=0.07, 95%CI, 0.01-0.82). Besides, positive association with pertussis was observed in subjects with a history of steroid treatment (OR=5.67) and those with a recent contact with a lasting cough (OR=4.12). When using a case-control study to evaluate the effectiveness of vaccines, particularly those for uncommon infectious diseases such as pertussis, the use of friend-controls may be optimal due to the fact that they shared a similar experience for exposure to the pathogen as the cases. In addition, to assess vaccine effectiveness as accurately as possible, the effects of confounding should be adequately controlled with a matching or analysis technique. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

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

    Science.gov (United States)

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

    1998-06-01

    A number of studies have reported associations between indoor biofuel air pollution in developing countries and chronic obstructive lung disease (COLD) in adults and acute lower respiratory infection (ALRI) in children. Most of these studies have used indirect measures of exposure and generally dealt inadequately with confounding. More reliable, quantified information about this presumed effect is an important pre-requisite for prevention, not least because of the technical, economic and cultural barriers to achieving substantial exposure reductions in the world's poorest households, where ambient pollution levels are typically between ten and a hundred times higher than recommended standards. This study was carried out as part of a programme of research designed to inform the development of intervention studies capable of providing quantified estimates of health benefits. The association between respiratory symptoms and the use of open fires and chimney woodstoves ('planchas'), and the distribution of confounding factors, were examined in a cross-sectional study of 340 women aged 15-45 years, living in a poor rural area in the western highlands of Guatemala. The prevalence of reported cough and phlegm was significantly higher for three of six symptom measures among women using open fires. Although this finding is consistent with a number of other studies, none has systematically examined the extent to which strong associations with confounding variables in these settings limit the ability of observational studies to define the effect of indoor air pollution adequately. Very strong associations (P air pollution and health, although there is a reasonable case for believing that the observed association is causal. Intervention studies are required for stronger evidence of this association, and more importantly, to determine the size of health benefit achievable through feasible exposure reductions.

  11. Reducing confounding and suppression effects in TCGA data: an integrated analysis of chemotherapy response in ovarian cancer

    Directory of Open Access Journals (Sweden)

    Hsu Fang-Han

    2012-10-01

    Full Text Available Abstract Background Despite initial response in adjuvant chemotherapy, ovarian cancer patients treated with the combination of paclitaxel and carboplatin frequently suffer from recurrence after few cycles of treatment, and the underlying mechanisms causing the chemoresistance remain unclear. Recently, The Cancer Genome Atlas (TCGA research network concluded an ovarian cancer study and released the dataset to the public. The TCGA dataset possesses large sample size, comprehensive molecular profiles, and clinical outcome information; however, because of the unknown molecular subtypes in ovarian cancer and the great diversity of adjuvant treatments TCGA patients went through, studying chemotherapeutic response using the TCGA data is difficult. Additionally, factors such as sample batches, patient ages, and tumor stages further confound or suppress the identification of relevant genes, and thus the biological functions and disease mechanisms. Results To address these issues, herein we propose an analysis procedure designed to reduce suppression effect by focusing on a specific chemotherapeutic treatment, and to remove confounding effects such as batch effect, patient's age, and tumor stages. The proposed procedure starts with a batch effect adjustment, followed by a rigorous sample selection process. Then, the gene expression, copy number, and methylation profiles from the TCGA ovarian cancer dataset are analyzed using a semi-supervised clustering method combined with a novel scoring function. As a result, two molecular classifications, one with poor copy number profiles and one with poor methylation profiles, enriched with unfavorable scores are identified. Compared with the samples enriched with favorable scores, these two classifications exhibit poor progression-free survival (PFS and might be associated with poor chemotherapy response specifically to the combination of paclitaxel and carboplatin. Significant genes and biological processes are

  12. Do patient and practice characteristics confound age-group differences in preferences for general practice care? A quantitative study

    Science.gov (United States)

    2013-01-01

    Background Previous research showed inconsistent results regarding the relationship between the age of patients and preference statements regarding GP care. This study investigates whether elderly patients have different preference scores and ranking orders concerning 58 preference statements for GP care than younger patients. Moreover, this study examines whether patient characteristics and practice location may confound the relationship between age and the categorisation of a preference score as very important. Methods Data of the Consumer Quality Index GP Care were used, which were collected in 32 general practices in the Netherlands. The rank order and preference score were calculated for 58 preference statements for four age groups (0–30, 31–50, 51–74, 75 years and older). Using chi-square tests and logistic regression analyses, it was investigated whether a significant relationship between age and preference score was confounded by patient characteristics and practice location. Results Elderly patients did not have a significant different ranking order for the preference statements than the other three age groups (r = 0.0193; p = 0.41). However, in 53% of the statements significant differences were found in preference score between the four age groups. Elderly patients categorized significantly less preference statements as ‘very important’. In most cases, the significant relationships were not confounded by gender, education, perceived health, the number of GP contacts and location of the GP practice. Conclusion The preferences of elderly patients for GP care concern the same items as younger patients. However, their preferences are less strong, which cannot be ascribed to gender, education, perceived health, the number of GP contacts and practice location. PMID:23800156

  13. Illinois highway materials sustainability efforts of 2015.

    Science.gov (United States)

    2016-08-01

    This report provides a summary of the sustainability efforts of the Illinois Department of Transportation (IDOT) in recycling : reclaimed materials in highway construction during calendar year 2015. This report meets the requirements of Illinois Publ...

  14. EU grid computing effort takes on malaria

    CERN Multimedia

    Lawrence, Stacy

    2006-01-01

    Malaria is the world's most common parasitic infection, affecting more thatn 500 million people annually and killing more than 1 million. In order to help combat malaria, CERN has launched a grid computing effort (1 page)

  15. Illinois highway materials sustainability efforts of 2014.

    Science.gov (United States)

    2015-08-01

    This report presents the 2014 sustainability efforts of the Illinois Department of Transportation (IDOT) in : recycling reclaimed materials in highway construction. This report meets the requirements of Illinois : Public Act 097-0314 by documenting I...

  16. Illinois highway materials sustainability efforts of 2016.

    Science.gov (United States)

    2017-07-04

    This report provides a summary of the sustainability efforts of the Illinois Department of Transportation (IDOT) in recycling : reclaimed materials in highway construction during calendar year 2016. This report meets the requirements of Illinois Publ...

  17. Illinois highway materials sustainability efforts of 2013.

    Science.gov (United States)

    2014-08-01

    This report presents the sustainability efforts of the Illinois Department of Transportation (IDOT) in : recycling and reclaiming materials for use in highway construction. This report meets the requirements of : Illinois Public Act 097-0314 by docum...

  18. Marital well-being and depression in Chinese marriage: Going beyond satisfaction and ruling out critical confounders.

    Science.gov (United States)

    Cao, Hongjian; Zhou, Nan; Fang, Xiaoyi; Fine, Mark

    2017-09-01

    Based on data obtained from 203 Chinese couples during the early years of marriage and utilizing the actor-partner interdependence model, this study examined the prospective associations between different aspects of marital well-being (i.e., marital satisfaction, instability, commitment, and closeness) and depressive symptoms (assessed 2 years later) while controlling for critical intrapersonal (i.e., neuroticism and self-esteem) and contextual (i.e., stressful life events) confounders. Results indicated that (a) when considering different aspects of marital well-being as predictors of depressive symptoms separately, each aspect was significantly associated with spouses' own subsequent depressive symptoms; (b) when examining various aspects of marital well-being simultaneously, only husbands' commitment, husbands' instability, and wives' instability were significantly associated with their own subsequent depressive symptoms above and beyond the other aspects; and (c) the associations between husbands' commitment, husbands' instability, and wives' instability and their own subsequent depressive symptoms remained significant even after controlling for potential major intrapersonal and contextual confounders. Such findings (a) provide evidence that the marital discord model of depression may apply to Chinese couples, (b) highlight the importance of going beyond marital (dis)satisfaction when examining the association between marital well-being and depression, and (c) demonstrate that marital well-being can account for unique variance in depressive symptoms above and beyond an array of intrapersonal and contextual risk factors. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  19. Analysis of Longitudinal Studies With Repeated Outcome Measures: Adjusting for Time-Dependent Confounding Using Conventional Methods.

    Science.gov (United States)

    Keogh, Ruth H; Daniel, Rhian M; VanderWeele, Tyler J; Vansteelandt, Stijn

    2018-05-01

    Estimation of causal effects of time-varying exposures using longitudinal data is a common problem in epidemiology. When there are time-varying confounders, which may include past outcomes, affected by prior exposure, standard regression methods can lead to bias. Methods such as inverse probability weighted estimation of marginal structural models have been developed to address this problem. However, in this paper we show how standard regression methods can be used, even in the presence of time-dependent confounding, to estimate the total effect of an exposure on a subsequent outcome by controlling appropriately for prior exposures, outcomes, and time-varying covariates. We refer to the resulting estimation approach as sequential conditional mean models (SCMMs), which can be fitted using generalized estimating equations. We outline this approach and describe how including propensity score adjustment is advantageous. We compare the causal effects being estimated using SCMMs and marginal structural models, and we compare the two approaches using simulations. SCMMs enable more precise inferences, with greater robustness against model misspecification via propensity score adjustment, and easily accommodate continuous exposures and interactions. A new test for direct effects of past exposures on a subsequent outcome is described.

  20. The obesity paradox in stable chronic heart failure does not persist after matching for indicators of disease severity and confounders.

    Science.gov (United States)

    Frankenstein, Lutz; Zugck, Christian; Nelles, Manfred; Schellberg, Dieter; Katus, Hugo A; Remppis, B Andrew

    2009-12-01

    To verify whether controlling for indicators of disease severity and confounders represents a solution to the obesity paradox in chronic heart failure (CHF). From a cohort of 1790 patients, we formed 230 nested matched triplets by individually matching patients with body mass index (BMI) > 30 kg/m(2) (Group 3), BMI 20-24.9 k/m(2) (Group 1) and BMI 25-29.9 kg/m(2) (Group 2), according to NT-proBNP, age, sex, and NYHA class (triplet = one matched patient from each group). Although in the pre-matching cohort, BMI group was a significant univariable prognostic indicator, it did not retain significance [heart rate (HR): 0.91, 95% CI: 0.78-1.05, chi(2): 1.67] when controlled for group propensities as covariates. Furthermore, in the matched cohort, 1-year mortality and 3-year mortality did not differ significantly. Here, BMI again failed to reach statistical significance for prognosis, either as a continuous or categorical variable, whether crude or adjusted. This result was confirmed in the patients not selected for matching. NT-proBNP, however, remained statistically significant (log(NT-proBNP): HR: 1.49, 95% CI: 1.13-1.97, chi(2): 7.82) after multivariable adjustment. The obesity paradox does not appear to persist in a matched setting with respect to indicators of disease severity and other confounders. NT-proBNP remains an independent prognostic indicator of adverse outcome irrespective of obesity status.

  1. Cross-sectional analysis of food choice frequency, sleep confounding beverages, and psychological distress predictors of sleep quality.

    Science.gov (United States)

    Knowlden, Adam P; Burns, Maranda; Harcrow, Andy; Shewmake, Meghan E

    2016-03-16

    Poor sleep quality is a significant public health problem. The role of nutrition in predicting sleep quality is a relatively unexplored area of inquiry. The purpose of this study was to evaluate the capacity of 10 food choice categories, sleep confounding beverages, and psychological distress to predict the sleep quality of college students. A logistic regression model comprising 10 food choice variables (healthy proteins, unhealthy proteins, healthy dairy, unhealthy dairy, healthy grains, unhealthy grains, healthy fruits and vegetables, unhealthy empty calories, healthy beverages, unhealthy beverages), sleep confounding beverages (caffeinated/alcoholic beverages), as well as psychological distress (low, moderate, serious distress) was computed to determine the capacity of the variables to predict sleep quality (good/poor). The odds of poor sleep quality were 32.4% lower for each unit of increased frequency of healthy proteins consumed (pempty calorie food choices consumed (p=0.003; OR=1.131), and 107.3% higher for those classified in the moderate psychological distress (p=0.016; OR=2.073). Collectively, healthy proteins, healthy dairy, unhealthy empty calories, and moderate psychological distress were moderately predictive of sleep quality in the sample (Nagelkerke R2=23.8%). Results of the study suggested higher frequency of consumption of healthy protein and healthy dairy food choices reduced the odds of poor sleep quality, while higher consumption of empty calories and moderate psychological distress increased the odds of poor sleep quality.

  2. Variation in faecal water content may confound estimates of gastro-intestinal parasite intensity in wild African herbivores.

    Science.gov (United States)

    Turner, W C; Cizauskas, C A; Getz, W M

    2010-03-01

    Estimates of parasite intensity within host populations are essential for many studies of host-parasite relationships. Here we evaluated the seasonal, age- and sex-related variability in faecal water content for two wild ungulate species, springbok (Antidorcas marsupialis) and plains zebra (Equus quagga). We then assessed whether or not faecal water content biased conclusions regarding differences in strongyle infection rates by season, age or sex. There was evidence of significant variation in faecal water content by season and age for both species, and by sex in springbok. Analyses of faecal egg counts demonstrated that sex was a near-significant factor in explaining variation in strongyle parasite infection rates in zebra (P = 0.055) and springbok (P = 0.052) using wet-weight faecal samples. However, once these intensity estimates were re-scaled by the percent of dry matter in the faeces, sex was no longer a significant factor (zebra, P = 0.268; springbok, P = 0.234). These results demonstrate that variation in faecal water content may confound analyses and could produce spurious conclusions, as was the case with host sex as a factor in the analysis. We thus recommend that researchers assess whether water variation could be a confounding factor when designing and performing research using faecal indices of parasite intensity.

  3. Measurement error, time lag, unmeasured confounding: Considerations for longitudinal estimation of the effect of a mediator in randomised clinical trials.

    Science.gov (United States)

    Goldsmith, K A; Chalder, T; White, P D; Sharpe, M; Pickles, A

    2018-06-01

    Clinical trials are expensive and time-consuming and so should also be used to study how treatments work, allowing for the evaluation of theoretical treatment models and refinement and improvement of treatments. These treatment processes can be studied using mediation analysis. Randomised treatment makes some of the assumptions of mediation models plausible, but the mediator-outcome relationship could remain subject to bias. In addition, mediation is assumed to be a temporally ordered longitudinal process, but estimation in most mediation studies to date has been cross-sectional and unable to explore this assumption. This study used longitudinal structural equation modelling of mediator and outcome measurements from the PACE trial of rehabilitative treatments for chronic fatigue syndrome (ISRCTN 54285094) to address these issues. In particular, autoregressive and simplex models were used to study measurement error in the mediator, different time lags in the mediator-outcome relationship, unmeasured confounding of the mediator and outcome, and the assumption of a constant mediator-outcome relationship over time. Results showed that allowing for measurement error and unmeasured confounding were important. Contemporaneous rather than lagged mediator-outcome effects were more consistent with the data, possibly due to the wide spacing of measurements. Assuming a constant mediator-outcome relationship over time increased precision.

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

    Directory of Open Access Journals (Sweden)

    Tianjiao Chu

    Full Text Available 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.

  5. Can statistic adjustment of OR minimize the potential confounding bias for meta-analysis of case-control study? A secondary data analysis.

    Science.gov (United States)

    Liu, Tianyi; Nie, Xiaolu; Wu, Zehao; Zhang, Ying; Feng, Guoshuang; Cai, Siyu; Lv, Yaqi; Peng, Xiaoxia

    2017-12-29

    Different confounder adjustment strategies were used to estimate odds ratios (ORs) in case-control study, i.e. how many confounders original studies adjusted and what the variables are. This secondary data analysis is aimed to detect whether there are potential biases caused by difference of confounding factor adjustment strategies in case-control study, and whether such bias would impact the summary effect size of meta-analysis. We included all meta-analyses that focused on the association between breast cancer and passive smoking among non-smoking women, as well as each original case-control studies included in these meta-analyses. The relative deviations (RDs) of each original study were calculated to detect how magnitude the adjustment would impact the estimation of ORs, compared with crude ORs. At the same time, a scatter diagram was sketched to describe the distribution of adjusted ORs with different number of adjusted confounders. Substantial inconsistency existed in meta-analysis of case-control studies, which would influence the precision of the summary effect size. First, mixed unadjusted and adjusted ORs were used to combine individual OR in majority of meta-analysis. Second, original studies with different adjustment strategies of confounders were combined, i.e. the number of adjusted confounders and different factors being adjusted in each original study. Third, adjustment did not make the effect size of original studies trend to constringency, which suggested that model fitting might have failed to correct the systematic error caused by confounding. The heterogeneity of confounder adjustment strategies in case-control studies may lead to further bias for summary effect size in meta-analyses, especially for weak or medium associations so that the direction of causal inference would be even reversed. Therefore, further methodological researches are needed, referring to the assessment of confounder adjustment strategies, as well as how to take this kind

  6. Tissue irradiator

    International Nuclear Information System (INIS)

    Hungate, F.P.; Riemath, W.F.; Bunnell, L.R.

    1975-01-01

    A tissue irradiator is provided for the in-vivo irradiation of body tissue. The irradiator comprises a radiation source material contained and completely encapsulated within vitreous carbon. An embodiment for use as an in-vivo blood irradiator comprises a cylindrical body having an axial bore therethrough. A radioisotope is contained within a first portion of vitreous carbon cylindrically surrounding the axial bore, and a containment portion of vitreous carbon surrounds the radioisotope containing portion, the two portions of vitreous carbon being integrally formed as a single unit. Connecting means are provided at each end of the cylindrical body to permit connections to blood-carrying vessels and to provide for passage of blood through the bore. In a preferred embodiment, the radioisotope is thulium-170 which is present in the irradiator in the form of thulium oxide. A method of producing the preferred blood irradiator is also provided, whereby nonradioactive thulium-169 is dispersed within a polyfurfuryl alcohol resin which is carbonized and fired to form the integral vitreous carbon body and the device is activated by neutron bombardment of the thulium-169 to produce the beta-emitting thulium-170

  7. Beyond total treatment effects in randomised controlled trials: Baseline measurement of intermediate outcomes needed to reduce confounding in mediation investigations.

    Science.gov (United States)

    Landau, Sabine; Emsley, Richard; Dunn, Graham

    2018-06-01

    Random allocation avoids confounding bias when estimating the average treatment effect. For continuous outcomes measured at post-treatment as well as prior to randomisation (baseline), analyses based on (A) post-treatment outcome alone, (B) change scores over the treatment phase or (C) conditioning on baseline values (analysis of covariance) provide unbiased estimators of the average treatment effect. The decision to include baseline values of the clinical outcome in the analysis is based on precision arguments, with analysis of covariance known to be most precise. Investigators increasingly carry out explanatory analyses to decompose total treatment effects into components that are mediated by an intermediate continuous outcome and a non-mediated part. Traditional mediation analysis might be performed based on (A) post-treatment values of the intermediate and clinical outcomes alone, (B) respective change scores or (C) conditioning on baseline measures of both intermediate and clinical outcomes. Using causal diagrams and Monte Carlo simulation, we investigated the performance of the three competing mediation approaches. We considered a data generating model that included three possible confounding processes involving baseline variables: The first two processes modelled baseline measures of the clinical variable or the intermediate variable as common causes of post-treatment measures of these two variables. The third process allowed the two baseline variables themselves to be correlated due to past common causes. We compared the analysis models implied by the competing mediation approaches with this data generating model to hypothesise likely biases in estimators, and tested these in a simulation study. We applied the methods to a randomised trial of pragmatic rehabilitation in patients with chronic fatigue syndrome, which examined the role of limiting activities as a mediator. Estimates of causal mediation effects derived by approach (A) will be biased if one of

  8. The use of aquatic bioconcentration factors in ecological risk assessments: Confounding issues, laboratory v/s modeled results

    International Nuclear Information System (INIS)

    Brandt, C.; Blanton, M.L.; Dirkes, R.

    1995-01-01

    Bioconcentration in aquatic systems is generally taken to refer to contaminant uptake through non-ingestion pathways (i.e., dermal and respiration uptake). Ecological risk assessments performed on aquatic systems often rely on published data on bioconcentration factors to calibrate models of exposure. However, many published BCFs, especially those from in situ studies, are confounded by uptake from ingestion of prey. As part of exposure assessment and risk analysis of the Columbia River's Hanford Reach, the authors tested a methodology to estimate radionuclide BCFs for several aquatic species in the Hanford Reach of the Columbia River. The iterative methodology solves for BCFs from known body burdens and environmental media concentrations. This paper provides BCF methodology description comparisons of BCF from literature and modeled values and how they were used in the exposure assessment and risk analysis of the Columbia River's Hanford Reach

  9. Modelling cardiac signal as a confound in EEG-fMRI and its application in focal epilepsy studies

    DEFF Research Database (Denmark)

    Liston, A. D.; Ellegaard Lund, Torben; Salek-Haddadi, A

    2006-01-01

    effects to be modelled, as effects of no interest. Our model is based on an over-complete basis set covering a linear relationship between cardiac-related MR signal and the phase of the cardiac cycle or time after pulse (TAP). This method showed that, on average, 24.6 +/- 10.9% of grey matter voxels......Cardiac noise has been shown to reduce the sensitivity of functional Magnetic Resonance Imaging (fMRI) to an experimental effect due to its confounding presence in the blood oxygenation level-dependent (BOLD) signal. Its effect is most severe in particular regions of the brain and a method is yet...... to take it into account in routine fMRI analysis. This paper reports the development of a general and robust technique to improve the reliability of EEG-fMRI studies to BOLD signal correlated with interictal epileptiform discharges (IEDs). In these studies, ECG is routinely recorded, enabling cardiac...

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

    OpenAIRE

    Hunte, Haslyn ER; King, Katherine; Hicken, Margaret; Lee, Hedwig; Lewis, Ten? T

    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 ...

  11. Instruction Emphasizing Effort Improves Physics Problem Solving

    Science.gov (United States)

    Li, Daoquan

    2012-01-01

    Effectively using strategies to solve complex problems is an important educational goal and is implicated in successful academic performance. However, people often do not spontaneously use the effective strategies unless they are motivated to do so. The present study was designed to test whether educating students about the importance of effort in…

  12. Student Effort, Consistency, and Online Performance

    Science.gov (United States)

    Patron, Hilde; Lopez, Salvador

    2011-01-01

    This paper examines how student effort, consistency, motivation, and marginal learning, influence student grades in an online course. We use data from eleven Microeconomics courses taught online for a total of 212 students. Our findings show that consistency, or less time variation, is a statistically significant explanatory variable, whereas…

  13. Net benefits of wildfire prevention education efforts

    Science.gov (United States)

    Jeffrey P. Prestemon; David T. Butry; Karen L. Abt; Ronda Sutphen

    2010-01-01

    Wildfire prevention education efforts involve a variety of methods, including airing public service announcements, distributing brochures, and making presentations, which are intended to reduce the occurrence of certain kinds of wildfires. A Poisson model of preventable Florida wildfires from 2002 to 2007 by fire management region was developed. Controlling for...

  14. Has Malaysia's antidrug effort been effective?

    Science.gov (United States)

    Scorzelli, J F

    1992-01-01

    It is a common belief that a massive effort in law enforcement, preventive education and rehabilitation will result in the elimination of a country's drug problem. Based on this premise. Malaysia in 1983 implemented such a multifaceted anti-drug strategy, and the results of a 1987 study by the author suggested that Malaysia's effort had begun to contribute to a steady decrease in the number of identified drug abusers. Although the number of drug-addicted individuals declined, the country's recidivism rates were still high. Because of this high relapse rate, Malaysia expanded their rehabilitation effort and developed a community transition program. In order to determine the impact of these changes on the country's battle against drug abuse, a follow-up study was conducted in 1990. The results of this study did not clearly demonstrate that the Malaysian effort had been successful in eliminating the problem of drug abuse, and raised some questions concerning the effectiveness of the country's drug treatment programs.

  15. Phase transitions in least-effort communications

    International Nuclear Information System (INIS)

    Prokopenko, Mikhail; Ay, Nihat; Obst, Oliver; Polani, Daniel

    2010-01-01

    We critically examine a model that attempts to explain the emergence of power laws (e.g., Zipf's law) in human language. The model is based on the principle of least effort in communications—specifically, the overall effort is balanced between the speaker effort and listener effort, with some trade-off. It has been shown that an information-theoretic interpretation of this principle is sufficiently rich to explain the emergence of Zipf's law in the vicinity of the transition between referentially useless systems (one signal for all referable objects) and indexical reference systems (one signal per object). The phase transition is defined in the space of communication accuracy (information content) expressed in terms of the trade-off parameter. Our study explicitly solves the continuous optimization problem, subsuming a recent, more specific result obtained within a discrete space. The obtained results contrast Zipf's law found by heuristic search (that attained only local minima) in the vicinity of the transition between referentially useless systems and indexical reference systems, with an inverse-factorial (sub-logarithmic) law found at the transition that corresponds to global minima. The inverse-factorial law is observed to be the most representative frequency distribution among optimal solutions

  16. The Galileo Teacher Training Program Global Efforts

    Science.gov (United States)

    Doran, R.; Pennypacker, C.; Ferlet, R.

    2012-08-01

    The Galileo Teacher Training Program (GTTP) successfully named representatives in nearly 100 nations in 2009, the International Year of Astronomy (IYA2009). The challenge had just begun. The steps ahead are how to reach educators that might benefit from our program and how to help build a more fair and science literate society, a society in which good tools and resources for science education are not the privilege of a few. From 2010 on our efforts have been to strengthen the newly formed network and learn how to equally help educators and students around the globe. New partnerships with other strong programs and institutions are being formed, sponsorship schemes being outlined, new tools and resources being publicized, and on-site and video conference training conducted all over the world. Efforts to officially accredit a GTTP curriculum are on the march and a stronger certification process being outlined. New science topics are being integrated in our effort and we now seek to discuss the path ahead with experts in this field and the community of users, opening the network to all corners of our beautiful blue dot. The main aim of this article is to open the discussion regarding the urgent issue of how to reawaken student interest in science, how to solve the gender inequality in science careers, and how to reach the underprivileged students and open to them the same possibilities. Efforts are in strengthening the newly formed network and learning how to equally help educators and students around the globe.

  17. Effort - Final technical report on task 3

    DEFF Research Database (Denmark)

    Bay, Niels; Henningsen, Poul; Eriksen, Morten

    The present report is documentation for the work carried out at DTU on the Brite/Euram project No. BE96-3340, contract No. BRPR-CT97-0398, with the title Enhanced Framework for forging design using reliable three-dimensional simulation (EFFORTS). The objective of task 3 is to determine data...

  18. Hydrogen economy: a little bit more effort

    International Nuclear Information System (INIS)

    Pauron, M.

    2008-01-01

    In few years, the use of hydrogen in economy has become a credible possibility. Today, billions of euros are invested in the hydrogen industry which is strengthened by technological advances in fuel cells development and by an increasing optimism. However, additional research efforts and more financing will be necessary to make the dream of an hydrogen-based economy a reality

  19. Workplace High Tech Spurs Retraining Efforts.

    Science.gov (United States)

    Davis, Dwight B.

    1984-01-01

    Discusses who should provide training for displaced workers who need new skills. Areas examined include: (1) the need for retraining; (2) current corporate efforts; (3) agreements in the automotive industry; (4) job quality; (5) the federal government's role; and (6) federal legislation related to the problem. (JN)

  20. Testosterone and reproductive effort in male primates.

    Science.gov (United States)

    Muller, Martin N

    2017-05-01

    Considerable evidence suggests that the steroid hormone testosterone mediates major life-history trade-offs in vertebrates, promoting mating effort at the expense of parenting effort or survival. Observations from a range of wild primates support the "Challenge Hypothesis," which posits that variation in male testosterone is more closely associated with aggressive mating competition than with reproductive physiology. In both seasonally and non-seasonally breeding species, males increase testosterone production primarily when competing for fecund females. In species where males compete to maintain long-term access to females, testosterone increases when males are threatened with losing access to females, rather than during mating periods. And when male status is linked to mating success, and dependent on aggression, high-ranking males normally maintain higher testosterone levels than subordinates, particularly when dominance hierarchies are unstable. Trade-offs between parenting effort and mating effort appear to be weak in most primates, because direct investment in the form of infant transport and provisioning is rare. Instead, infant protection is the primary form of paternal investment in the order. Testosterone does not inhibit this form of investment, which relies on male aggression. Testosterone has a wide range of effects in primates that plausibly function to support male competitive behavior. These include psychological effects related to dominance striving, analgesic effects, and effects on the development and maintenance of the armaments and adornments that males employ in mating competition. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Reasonable limits to radiation protection efforts

    International Nuclear Information System (INIS)

    Gonen, Y.G.

    1982-01-01

    It is shown that change in life expectancy (ΔLE) is an improved estimate for risks and safety efforts, reflecting the relevant social goal. A cost-effectiveness index, safety investment/ΔLE, is defined. The harm from low level radiation is seen as a reduction of life expectancy instead of an increased probability of contracting cancer. (author)

  2. Educational gains in cause-specific mortality: Accounting for cognitive ability and family-level confounders using propensity score weighting.

    Science.gov (United States)

    Bijwaard, Govert E; Myrskylä, Mikko; Tynelius, Per; Rasmussen, Finn

    2017-07-01

    A negative educational gradient has been found for many causes of death. This association may be partly explained by confounding factors that affect both educational attainment and mortality. We correct the cause-specific educational gradient for observed individual background and unobserved family factors using an innovative method based on months lost due to a specific cause of death re-weighted by the probability of attaining a higher educational level. We use data on men with brothers from the Swedish Military Conscription Registry (1951-1983), linked to administrative registers. This dataset of some 700,000 men allows us to distinguish between five education levels and many causes of death. The empirical results reveal that raising the educational level from primary to tertiary would result in an additional 20 months of survival between ages 18 and 63. This improvement in mortality is mainly attributable to fewer deaths from external causes. The highly educated gain more than nine months due to the reduction in deaths from external causes, but gain only two months due to the reduction in cancer mortality and four months due to the reduction in cardiovascular mortality. Ignoring confounding would lead to an underestimation of the gains by educational attainment, especially for the less educated. Our results imply that if the education distribution of 50,000 Swedish men from the 1951 cohort were replaced with that of the corresponding 1983 cohort, 22% of the person-years that were lost to death between ages 18 and 63 would have been saved for this cohort. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    Monika eFleischhauer

    2013-09-01

    Full Text Available 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, 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

  4. High SNR Acquisitions Improve the Repeatability of Liver Fat Quantification Using Confounder-corrected Chemical Shift-encoded MR Imaging

    Science.gov (United States)

    Motosugi, Utaroh; Hernando, Diego; Wiens, Curtis; Bannas, Peter; Reeder, Scott. B

    2017-01-01

    Purpose: To determine whether high signal-to-noise ratio (SNR) acquisitions improve the repeatability of liver proton density fat fraction (PDFF) measurements using confounder-corrected chemical shift-encoded magnetic resonance (MR) imaging (CSE-MRI). Materials and Methods: Eleven fat-water phantoms were scanned with 8 different protocols with varying SNR. After repositioning the phantoms, the same scans were repeated to evaluate the test-retest repeatability. Next, an in vivo study was performed with 20 volunteers and 28 patients scheduled for liver magnetic resonance imaging (MRI). Two CSE-MRI protocols with standard- and high-SNR were repeated to assess test-retest repeatability. MR spectroscopy (MRS)-based PDFF was acquired as a standard of reference. The standard deviation (SD) of the difference (Δ) of PDFF measured in the two repeated scans was defined to ascertain repeatability. The correlation between PDFF of CSE-MRI and MRS was calculated to assess accuracy. The SD of Δ and correlation coefficients of the two protocols (standard- and high-SNR) were compared using F-test and t-test, respectively. Two reconstruction algorithms (complex-based and magnitude-based) were used for both the phantom and in vivo experiments. Results: The phantom study demonstrated that higher SNR improved the repeatability for both complex- and magnitude-based reconstruction. Similarly, the in vivo study demonstrated that the repeatability of the high-SNR protocol (SD of Δ = 0.53 for complex- and = 0.85 for magnitude-based fit) was significantly higher than using the standard-SNR protocol (0.77 for complex, P magnitude-based fit, P = 0.003). No significant difference was observed in the accuracy between standard- and high-SNR protocols. Conclusion: Higher SNR improves the repeatability of fat quantification using confounder-corrected CSE-MRI. PMID:28190853

  5. Accounting for the Confound of Meninges in Segmenting Entorhinal and Perirhinal Cortices in T1-Weighted MRI.

    Science.gov (United States)

    Xie, Long; Wisse, Laura E M; Das, Sandhitsu R; Wang, Hongzhi; Wolk, David A; Manjón, Jose V; Yushkevich, Paul A

    2016-10-01

    Quantification of medial temporal lobe (MTL) cortices, including entorhinal cortex (ERC) and perirhinal cortex (PRC), from in vivo MRI is desirable for studying the human memory system as well as in early diagnosis and monitoring of Alzheimer's disease. However, ERC and PRC are commonly over-segmented in T1-weighted (T1w) MRI because of the adjacent meninges that have similar intensity to gray matter in T1 contrast. This introduces errors in the quantification and could potentially confound imaging studies of ERC/PRC. In this paper, we propose to segment MTL cortices along with the adjacent meninges in T1w MRI using an established multi-atlas segmentation framework together with super-resolution technique. Experimental results comparing the proposed pipeline with existing pipelines support the notion that a large portion of meninges is segmented as gray matter by existing algorithms but not by our algorithm. Cross-validation experiments demonstrate promising segmentation accuracy. Further, agreement between the volume and thickness measures from the proposed pipeline and those from the manual segmentations increase dramatically as a result of accounting for the confound of meninges. Evaluated in the context of group discrimination between patients with amnestic mild cognitive impairment and normal controls, the proposed pipeline generates more biologically plausible results and improves the statistical power in discriminating groups in absolute terms comparing to other techniques using T1w MRI. Although the performance of the proposed pipeline is inferior to that using T2-weighted MRI, which is optimized to image MTL sub-structures, the proposed pipeline could still provide important utilities in analyzing many existing large datasets that only have T1w MRI available.

  6. The Application of Tissue Engineering Procedures to Repair the Larynx

    Science.gov (United States)

    Ringel, Robert L.; Kahane, Joel C.; Hillsamer, Peter J.; Lee, Annie S.; Badylak, Stephen F.

    2006-01-01

    The field of tissue engineering/regenerative medicine combines the quantitative principles of engineering with the principles of the life sciences toward the goal of reconstituting structurally and functionally normal tissues and organs. There has been relatively little application of tissue engineering efforts toward the organs of speech, voice,…

  7. Student Effort, Consistency and Online Performance

    Directory of Open Access Journals (Sweden)

    Hilde Patron

    2011-07-01

    Full Text Available This paper examines how student effort, consistency, motivation, and marginal learning, influence student grades in an online course. We use data from eleven Microeconomics courses taught online for a total of 212 students. Our findings show that consistency, or less time variation, is a statistically significant explanatory variable, whereas effort, or total minutes spent online, is not. Other independent variables include GPA and the difference between a pre-test and a post-test. The GPA is used as a measure of motivation, and the difference between a post-test and pre-test as marginal learning. As expected, the level of motivation is found statistically significant at a 99% confidence level, and marginal learning is also significant at a 95% level.

  8. Summary of process research analysis efforts

    Science.gov (United States)

    Burger, D. R.

    1985-01-01

    A summary of solar-cell process research analysis efforts was presented. Process design and cell design are interactive efforts where technology from integrated circuit processes and other processes are blended. The primary factors that control cell efficiency are: (1) the bulk parameters of the available sheet material, (2) the retention and enhancement of these bulk parameters, and (3) the cell design and the cost to produce versus the finished cells performance. The process sequences need to be tailored to be compatible with the sheet form, the cell shape form, and the processing equipment. New process options that require further evaluation and utilization are lasers, robotics, thermal pulse techniques, and new materials. There are numerous process control techniques that can be adapted and used that will improve product uniformity and reduced costs. Two factors that can lead to longer life modules are the use of solar cell diffusion barriers and improved encapsulation.

  9. The growth of tissue engineering.

    Science.gov (United States)

    Lysaght, M J; Reyes, J

    2001-10-01

    This report draws upon data from a variety of sources to estimate the size, scope, and growth rate of the contemporary tissue engineering enterprise. At the beginning of 2001, tissue engineering research and development was being pursued by 3,300 scientists and support staff in more than 70 startup companies or business units with a combined annual expenditure of over $600 million. Spending by tissue engineering firms has been growing at a compound annual rate of 16%, and the aggregate investment since 1990 now exceeds $3.5 billion. At the beginning of 2001, the net capital value of the 16 publicly traded tissue engineering startups had reached $2.6 billion. Firms focusing on structural applications (skin, cartilage, bone, cardiac prosthesis, and the like) comprise the fastest growing segment. In contrast, efforts in biohybrid organs and other metabolic applications have contracted over the past few years. The number of companies involved in stem cells and regenerative medicine is rapidly increasing, and this area represents the most likely nidus of future growth for tissue engineering. A notable recent trend has been the emergence of a strong commercial activity in tissue engineering outside the United States, with at least 16 European or Australian companies (22% of total) now active.

  10. Non-proliferation efforts in South Asia

    International Nuclear Information System (INIS)

    Chellaney, B.

    1994-01-01

    Southern Asia is one of the most volatile regions in the world because of inter-State and intra-State conflicts. Security in the region highly depends on the rival capabilities of the involved states, Pakistan, India, China. Increased Confidence building and nuclear transparency are becoming more significant issues in attaining stability in the region, although non-proliferation efforts in this region have attained little headway

  11. Some recent efforts toward high density implosions

    International Nuclear Information System (INIS)

    McClellan, G.E.

    1980-01-01

    Some recent Livermore efforts towards achieving high-density implosions are presented. The implosion dynamics necessary to compress DT fuel to 10 to 100 times liquid density are discussed. Methods of diagnosing the maximum DT density for a specific design are presented along with results to date. The dynamics of the double-shelled target with an exploding outer shell are described, and some preliminary experimental results are presented

  12. Evaluative language, cognitive effort and attitude change.

    OpenAIRE

    van der Pligt, J.; van Schie, E.C.M.; Martijn, C.

    1994-01-01

    Tested the hypotheses that evaluatively biased language influences attitudes and that the magnitude and persistence of attitude change depends on the amount of cognitive effort. 132 undergraduates participated in the experiment, which used material focusing on the issue of restricting adolescent driving over the weekends to reduce the number of fatal traffic accidents. Results indicate that evaluatively biased language can affect attitudes. Using words that evaluate the pro-position positivel...

  13. Efforts to identify spore forming bacillus

    Energy Technology Data Exchange (ETDEWEB)

    Zuleiha, M.S.; Hilmy, N. (National Atomic Energy Agency, Jakarta (Indonesia). Pasar Djumat Research Centre)

    1982-04-01

    Efforts to identify 47 species of radioresistant spore forming bacillus sp. isolated from locally produced medical devices have been carried out. The identifications was conducted using 19 kinds of biochemical tests and compared to species to bacillus subtilis W. T.; bacillus pumilus E 601 and bacillus sphaericus Csub(I)A. The results showed that bacillus sp. examined could be divided into 6 groups, i.e. bacillus cereus; bacillus subtilis; bacillus stearothermophylus; bacillus coagulans; bacillus sphaericus and bacillus circulans.

  14. Efforts to identify spore forming bacillus

    International Nuclear Information System (INIS)

    Zuleiha, M.S.; Hilmy, Nazly

    1982-01-01

    Efforts to identify 47 species of radioresistant spore forming bacillus sp. isolated from locally produced medical devices have been carried out. The identifications was conducted using 19 kinds of biochemical tests and compared to species to bacillus subtilis W. T.; bacillus pumilus E 601 and bacillus sphaericus Csub(I)A. The results showed that bacillus sp. examined could be divided into 6 groups, i.e. bacillus cereus; bacillus subtilis; bacillus stearothermophylus; bacillus coagulans; bacillus sphaericus and bacillus circulans. (author)

  15. Environmental Determinants of Lexical Processing Effort

    OpenAIRE

    McDonald, Scott

    2000-01-01

    Institute for Adaptive and Neural Computation A central concern of psycholinguistic research is explaining the relative ease or difficulty involved in processing words. In this thesis, we explore the connection between lexical processing effort and measurable properties of the linguistic environment. Distributional information (information about a word’s contexts of use) is easily extracted from large language corpora in the form of co-occurrence statistics. We claim that su...

  16. Duke Power's liquid radwaste processing improvement efforts

    International Nuclear Information System (INIS)

    Baker, R.E. Jr.; Bramblett, J.W.

    1995-01-01

    The rising cost of processing liquid radwaste and industry efforts to reduce offsite isotopic contributions has drawn greater attention to the liquid radwaste area. Because of economic pressures to reduce cost and simultaneously improve performance, Duke Power has undertaken a wide ranging effort to cost effectively achieve improvements in the liquid radwaste processing area. Duke Power has achieved significant reductions over recent years in the release of curies to the environment from the Liquid Radwaste Treatmentt systems at its Catawba, McGuire, and Oconee stations. System wide site curie reductions of 78% have been achieved in a 3 year period. These curie reductions have been achieved while simultaneously reducing the amount of media used to accomplish treatment. The curie and media usage reductions have been achieved at low capital cost expenditures. A large number of approaches and projects have been used to achieve these curie and media usage reductions. This paper will describe the various projects and the associated results for Duke Power's processing improvement efforts. The subjects/projects which will be described include: (1) Cooperative philosophy between stations (2) Source Control (3) Processing Improvements (4) Technology Testing

  17. Effort-reward imbalance at work and the risk of antidepressant treatment in the Danish workforce

    DEFF Research Database (Denmark)

    Nielsen, Maj Britt D.; Madsen, Ida E. H.; Aust, Birgit

    2016-01-01

    Background: Previous studies have shown that high effort-reward imbalance (ERI) at work is a risk factor for the onset of self-reported depressive symptoms. In this study, we examined whether ERI predicts risk of treatment with antidepressant medication in a representative sample of the Danish...... workforce. Methods: We linked survey data on ERI and covariates of 4541 participants from the Danish Work Environment Cohort Study 2000 with the Danish National Prescription Registry that includes all legally purchased prescription drugs at pharmacies in Denmark since 1995. Participants with a history....... Results: A total of 309 (6.8%) participants started antidepressant treatment during follow-up. Exposure to ERI at baseline was not related to risk of antidepressant treatment (hazard ratio: 0.91, 95% CI=0.81–1.03 after adjustment for potential confounders). Limitations: The use of antidepressant treatment...

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

    Science.gov (United States)

    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 interpersonal discrimination remained a positive predictor of depressive symptoms (beta: 0.1176, p 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

  19. Pioneering efforts to control AIDS. Review: IHO.

    Science.gov (United States)

    Chatterji, A; Sehgal, K

    1995-01-01

    The Indian Health Organisation (IHO) is a nongovernmental organization based in Bombay with more than 12 years experience in HIV/AIDS prevention and control efforts. It has attacked ignorance and prejudice via communication efforts. IHO has created a bond with some hospital systems of Bombay. IHO disseminated information about HIV/AIDS in Bombay's red light districts and has bridged the gap between the city's medical establishment and the community most in need. IHO's aggressive street-level fighting in a sector replete with sensitive issues has somewhat isolated it from mainstream national NGOs involved in HIV/AIDS education and control as well as from the medical establishment and potential partners. IHO funds have been reduced, forcing IHO to reduce intervention programs and responses to field demands. It suffers from a high rate of turnover among middle management staff. IHO's chief advantage is its confidence gained over the past 12 years. IHO has clearly delineated the direction it wants to go: care and support programs for persons affected by HIV/AIDS and for commercial sex workers to allow them to quit prostitution, orphan care, and development of training institutions for the education and motivation of medical personnel on HIV/AIDS care and prevention. It plans to build a hospice for AIDS patients and orphans and a training center. Training activities will vary from one-week orientation programs to three-month certificate courses for medical workers, NGOs, and managers from the commercial sector. IHO is prepared to share its experiences in combating HIV/AIDS in Bombay in a team effort. As official and bilateral funding has been decreasing, IHO has targeted industry for funding. Industry has responded, which enables IHO to sustain its core programs and approaches. IHO observations show a decrease in the number of men visiting red-light districts. IHO enjoys a positive relationship with Bombay's media reporting on AIDS.

  20. Economic growth, biodiversity loss and conservation effort.

    Science.gov (United States)

    Dietz, Simon; Adger, W Neil

    2003-05-01

    This paper investigates the relationship between economic growth, biodiversity loss and efforts to conserve biodiversity using a combination of panel and cross section data. If economic growth is a cause of biodiversity loss through habitat transformation and other means, then we would expect an inverse relationship. But if higher levels of income are associated with increasing real demand for biodiversity conservation, then investment to protect remaining diversity should grow and the rate of biodiversity loss should slow with growth. Initially, economic growth and biodiversity loss are examined within the framework of the environmental Kuznets hypothesis. Biodiversity is represented by predicted species richness, generated for tropical terrestrial biodiversity using a species-area relationship. The environmental Kuznets hypothesis is investigated with reference to comparison of fixed and random effects models to allow the relationship to vary for each country. It is concluded that an environmental Kuznets curve between income and rates of loss of habitat and species does not exist in this case. The role of conservation effort in addressing environmental problems is examined through state protection of land and the regulation of trade in endangered species, two important means of biodiversity conservation. This analysis shows that the extent of government environmental policy increases with economic development. We argue that, although the data are problematic, the implications of these models is that conservation effort can only ever result in a partial deceleration of biodiversity decline partly because protected areas serve multiple functions and are not necessarily designated to protect biodiversity. Nevertheless institutional and policy response components of the income biodiversity relationship are important but are not well captured through cross-country regression analysis.

  1. Educational Outreach Efforts at the NNDC

    International Nuclear Information System (INIS)

    Holden, N.E.

    2014-01-01

    Isotopes and nuclides are important in our everyday life. The general public and most students are never exposed to the concepts of stable and radioactive isotopes/nuclides. The National Nuclear Data Center (NNDC) is involved in an international project to develop a Periodic Table of the Isotopes for the educational community to illustrate the importance of isotopes and nuclides in understanding the world around us. This effort should aid teachers in introducing these concepts to students from the high school to the graduate school level

  2. Effort variation regularization in sound field reproduction

    DEFF Research Database (Denmark)

    Stefanakis, Nick; Jacobsen, Finn; Sarris, Ioannis

    2010-01-01

    In this paper, active control is used in order to reproduce a given sound field in an extended spatial region. A method is proposed which minimizes the reproduction error at a number of control positions with the reproduction sources holding a certain relation within their complex strengths......), and adaptive wave field synthesis (AWFS), both under free-field conditions and in reverberant rooms. It is shown that effort variation regularization overcomes the problems associated with small spaces and with a low ratio of direct to reverberant energy, improving thus the reproduction accuracy...

  3. Multipartite Entanglement Detection with Minimal Effort

    Science.gov (United States)

    Knips, Lukas; Schwemmer, Christian; Klein, Nico; Wieśniak, Marcin; Weinfurter, Harald

    2016-11-01

    Certifying entanglement of a multipartite state is generally considered a demanding task. Since an N qubit state is parametrized by 4N-1 real numbers, one might naively expect that the measurement effort of generic entanglement detection also scales exponentially with N . Here, we introduce a general scheme to construct efficient witnesses requiring a constant number of measurements independent of the number of qubits for states like, e.g., Greenberger-Horne-Zeilinger states, cluster states, and Dicke states. For four qubits, we apply this novel method to experimental realizations of the aforementioned states and prove genuine four-partite entanglement with two measurement settings only.

  4. Pattern classification of brain activation during emotional processing in subclinical depression: psychosis proneness as potential confounding factor

    Directory of Open Access Journals (Sweden)

    Gemma Modinos

    2013-02-01

    Full Text Available We used Support Vector Machine (SVM to perform multivariate pattern classification based on brain activation during emotional processing in healthy participants with subclinical depressive symptoms. Six-hundred undergraduate students completed the Beck Depression Inventory II (BDI-II. Two groups were subsequently formed: (i subclinical (mild mood disturbance (n = 17 and (ii no mood disturbance (n = 17. Participants also completed a self-report questionnaire on subclinical psychotic symptoms, the Community Assessment of Psychic Experiences Questionnaire (CAPE positive subscale. The functional magnetic resonance imaging (fMRI paradigm entailed passive viewing of negative emotional and neutral scenes. The pattern of brain activity during emotional processing allowed correct group classification with an overall accuracy of 77% (p = 0.002, within a network of regions including the amygdala, insula, anterior cingulate cortex and medial prefrontal cortex. However, further analysis suggested that the classification accuracy could also be explained by subclinical psychotic symptom scores (correlation with SVM weights r = 0.459, p = 0.006. Psychosis proneness may thus be a confounding factor for neuroimaging studies in subclinical depression.

  5. Is the co-occurrence of smoking and poor consumption of fruits and vegetables confounded by socioeconomic conditions?

    Science.gov (United States)

    Muff, Christine; Dragano, N; Jöckel, K-H; Moebus, S; Möhlenkamp, S; Erbel, R; Mann, K; Siegrist, J

    2010-08-01

    As smoking and unhealthy diet are more prevalent in lower socioeconomic groups, this study aims at exploring whether associations between smoking and fruit and vegetable consumption are confounded by socioeconomic conditions or if smoking is independently associated with consumption. Cross-sectional analyses of 4,814 middle-aged participants from the Heinz Nixdorf recall study, a population-based cohort study in Germany. Fruit and vegetable consumption was assessed by a food frequency questionnaire. Education and income were used as indicators for socioeconomic groups. Logistic regression models were run to estimate odds ratios for consumption by smoking status. Smoking is associated with poor consumption of fruits and raw vegetables/salad in both genders, and with poor consumption of boiled vegetables and fruit/vegetable juice in men. Importantly, poor consumption is related to smoking independently of people's socioeconomic conditions. The findings imply that smokers in all socioeconomic groups are at higher risk for unhealthy intake of fruits and vegetables. Public health interventions targeted to smokers should include dietary instructions.

  6. The associations between serum brain-derived neurotrophic factor, potential confounders, and cognitive decline: a longitudinal study.

    Directory of Open Access Journals (Sweden)

    Jasmine Nettiksimmons

    Full Text Available Brain-derived neurotrophic factor (BDNF plays a role in the maintenance and function of neurons. Although persons with Alzheimer's disease have lower cortical levels of BDNF, evidence regarding the association between circulating BDNF and cognitive function is conflicting. We sought to determine the correlates of BDNF level and whether BDNF level was prospectively associated with cognitive decline in healthy older adults. We measured serum BDNF near baseline in 912 individuals. Cognitive status was assessed repeatedly with the modified Mini-Mental Status Examination and the Digit Symbol Substitution test over the next 10 years. We evaluated the association between BDNF and cognitive decline with longitudinal models. We also assessed the association between BDNF level and demographics, comorbidities and health behaviors. We found an association between serum BDNF and several characteristics that are also associated with dementia (race and depression, suggesting that future studies should control for these potential confounders. We did not find evidence of a longitudinal association between serum BDNF and subsequent cognitive test trajectories in older adults, although we did identify a potential trend toward a cross-sectional association. Our results suggest that serum BDNF may have limited utility as a biomarker of prospective cognitive decline.

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

    Science.gov (United States)

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

    2015-01-01

    This work addresses the existing and emerging evidence of overlap within the environmental and genetic profiles of multiple sclerosis (MS) and schizophrenia. 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. 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. We report suggestive evidence of an association with vitamin D status in established psychosis (ß standardized=0.51, P=0.04). The logistic model fit significantly benefited from controlling for body mass index, depression and ethnicity (χ (2)=91.7; 2 degrees of freedom (df); P=1.2×10(20)). 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.

  8. Pattern classification of brain activation during emotional processing in subclinical depression: psychosis proneness as potential confounding factor.

    Science.gov (United States)

    Modinos, Gemma; Mechelli, Andrea; Pettersson-Yeo, William; Allen, Paul; McGuire, Philip; Aleman, Andre

    2013-01-01

    We used Support Vector Machine (SVM) to perform multivariate pattern classification based on brain activation during emotional processing in healthy participants with subclinical depressive symptoms. Six-hundred undergraduate students completed the Beck Depression Inventory II (BDI-II). Two groups were subsequently formed: (i) subclinical (mild) mood disturbance (n = 17) and (ii) no mood disturbance (n = 17). Participants also completed a self-report questionnaire on subclinical psychotic symptoms, the Community Assessment of Psychic Experiences Questionnaire (CAPE) positive subscale. The functional magnetic resonance imaging (fMRI) paradigm entailed passive viewing of negative emotional and neutral scenes. The pattern of brain activity during emotional processing allowed correct group classification with an overall accuracy of 77% (p = 0.002), within a network of regions including the amygdala, insula, anterior cingulate cortex and medial prefrontal cortex. However, further analysis suggested that the classification accuracy could also be explained by subclinical psychotic symptom scores (correlation with SVM weights r = 0.459, p = 0.006). Psychosis proneness may thus be a confounding factor for neuroimaging studies in subclinical depression.

  9. Adherent Human Alveolar Macrophages Exhibit a Transient Pro-Inflammatory Profile That Confounds Responses to Innate Immune Stimulation

    Science.gov (United States)

    Tomlinson, Gillian S.; Booth, Helen; Petit, Sarah J.; Potton, Elspeth; Towers, Greg J.; Miller, Robert F.; Chain, Benjamin M.; Noursadeghi, Mahdad

    2012-01-01

    Alveolar macrophages (AM) are thought to have a key role in the immunopathogenesis of respiratory diseases. We sought to test the hypothesis that human AM exhibit an anti-inflammatory bias by making genome-wide comparisons with monocyte derived macrophages (MDM). Adherent AM obtained by bronchoalveolar lavage of patients under investigation for haemoptysis, but found to have no respiratory pathology, were compared to MDM from healthy volunteers by whole genome transcriptional profiling before and after innate immune stimulation. We found that freshly isolated AM exhibited a marked pro-inflammatory transcriptional signature. High levels of basal pro-inflammatory gene expression gave the impression of attenuated responses to lipopolysaccharide (LPS) and the RNA analogue, poly IC, but in rested cells pro-inflammatory gene expression declined and transcriptional responsiveness to these stimuli was restored. In comparison to MDM, both freshly isolated and rested AM showed upregulation of MHC class II molecules. In most experimental paradigms ex vivo adherent AM are used immediately after isolation. Therefore, the confounding effects of their pro-inflammatory profile at baseline need careful consideration. Moreover, despite the prevailing view that AM have an anti-inflammatory bias, our data clearly show that they can adopt a striking pro-inflammatory phenotype, and may have greater capacity for presentation of exogenous antigens than MDM. PMID:22768282

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

    Science.gov (United States)

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

    2016-10-01

    Mycobacterium leprae-specific serological and cell-mediated-immunity/CMI test were evaluated for the differential diagnosis of multibacillary/MB, and paucibacillary/PB leprosy from other dermatoses. Whole-blood assay/WBA/IFNγ stimulated with LID-1 antigen and ELISA tests for IgG to LID-1 and IgM to PGL-I were performed. WBA/LID-1/IFNγ production was observed in 72% PB, 11% MB leprosy, 38% dermatoses, 40% healthy endemic controls/EC. The receiver operating curve/ROC for WBA/LID-1 in PB versus other dermatoses showed 72.5% sensitivity, 61.5% specificity and an area-under-the-curve/AUC=0.75; 74% positive predictive value/PPV, 59% negative predictive value/NPV. Anti PGL-I serology was positive in 67% MB, 8% PB leprosy, 6% of other dermatoses; its sensitivity for MB=66%, specificity=93%, AUC=0.89; PPV=91%, NPV=72%. Anti-LID-1 serology was positive in 87% MB, 7% PB leprosy, all other participants were seronegative; 87.5% sensitivity for MB, 100% specificity, AUC=0.97; PPV=100%, NPV=88%. In highly endemic areas anti-LID-1/PGL-I serology and WBA/LID-1-represent useful tools for the differential diagnosis of leprosy from other confounding dermatoses. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. International Efforts for the Nuclear Security

    International Nuclear Information System (INIS)

    Yoo, Ho Sik; Kwak, Sung Woo; Lee, Ho Jin; Shim, Hye Won; Lee, Jong Uk

    2005-01-01

    Many concerns have been focused on the nuclear security since the 9.11. With increasing the threat related to nuclear material and nuclear facilities, the demand of strengthening the international physical protection system has been raised. Along with this, the international communities are making their efforts to increase nuclear security. The agreement of revising the 'Convention on Physical Protection of Nuclear Materials'(hereafter, CPPNM), which was held in Vienna on the July of 2005, was one of these efforts. U.N is also preparing the 'International Convention for the Suppression of Acts of Nuclear Terrorism' to show its firm resolution against nuclear terror. It is important to understand what measures should be taken to meet the international standard for establishing national physical protection system. To do this, international trend on the physical protection system such as CPPNM and U.N. convention should be followed. This paper explains about the content of the CPPNM and U.N convention. They will be helpful to consolidate the physical protection system in Korea

  12. Sidoarjo mudflow phenomenon and its mitigation efforts

    Science.gov (United States)

    Wibowo, H. T.; Williams, V.

    2009-12-01

    Hot mud first erupted in Siring village, Porong, Sidoarjo May 29th 2006. The mud first appeared approximately 200 meters from Banjarpanji-1 gas-drilling well. The mud volume increased day by day, from 5000 cubic meters per day on June 2006 to 50,000 cubic meters per day during the last of 2006, and then increased to 100,000-120,000 cubic meters per day during 2007. Flow still continues at a high rate. Moreover, as the water content has gone down, the clast content has gone up. Consequently, there is now the threat of large amounts of solid material being erupted throughout the area. Also, there is the issue of subsurface collapse and ground surface subsidence. The Indonesian government has set up a permanent team to support communities affected by the mudflow that has swamped a number of villages near LUSI. Toll roads, railway tracks and factories also have been submerged and over 35,000 people have been displaced to date. The Sidoarjo Mudflow Mitigation Agency [SMMA, BPLS (Indonesia)] replaces a temporary team called National Team PSLS which was installed for seven months and ended their work on 7 April 2007. BPLS was set up by Presidential Regulation No. 14 / 2007, and it will have to cover the costs related to the social impact of the disaster, especially outside the swamped area. BPLS is the central government institution designated to handle the disaster by coordination with both the drilling company and local (provincial and district) governments. It takes a comprehensive, integrated and holistic approach for its mission and challenges. Those are: 1) How to stop the mudflow, 2) How to mitigate the impacts of the mudflow, and 3) How to minimize the social, economic, environmental impacts, and infrastructure impacts. The mudflow mitigation efforts were constrained by dynamic geology conditions, as well as resistance to certain measures by residents of impacted areas. Giant dykes were built to retain the spreading mud, and the mudflow from the main vent was

  13. Time-Dependent Confounding in the Study of the Effects of Regular Physical Activity in Chronic Obstructive Pulmonary Disease: An Application of the Marginal Structural Model

    DEFF Research Database (Denmark)

    Garcia-Aymerich, Judith; Lange, Peter; Serra, Ignasi

    2008-01-01

    PURPOSE: Results from longitudinal studies about the association between physical activity and chronic obstructive pulmonary disease (COPD) may have been biased because they did not properly adjust for time-dependent confounders. Marginal structural models (MSMs) have been proposed to address...... this type of confounding. We sought to assess the presence of time-dependent confounding in the association between physical activity and COPD development and course by comparing risk estimates between standard statistical methods and MSMs. METHODS: By using the population-based cohort Copenhagen City Heart...... Study, 6,568 subjects selected from the general population in 1976 were followed up until 2004 with three repeated examinations. RESULTS: Moderate to high compared with low physical activity was associated with a reduced risk of developing COPD both in the standard analysis (odds ratio [OR] 0.76, p = 0...

  14. Supporting Students as Scientists: One Mission's Efforts

    Science.gov (United States)

    Taylor, J.; Chambers, L. H.; Trepte, C. R.

    2012-12-01

    NASA's CALIPSO satellite mission provides an array of opportunities for teachers, students, and the general public. In developing our latest plan for education and public outreach, CALIPSO focused on efforts that would support students as scientists. CALIPSO EPO activities are aimed at inspiring young scientists through multiple avenues of potential contact, including: educator professional development, student-scientist mentoring, curriculum resource development, and public outreach through collaborative mission efforts. In this session, we will explore how these avenues complement one another and take a closer look at the development of the educator professional development activities. As part of CALIPSO's EPO efforts, we have developed the GLOBE Atmosphere Investigations Programs (AIP). The program encourages students to engage in authentic science through research on the atmosphere. The National Research Council (NRC) has emphasized the importance of teaching scientific inquiry in the National Science Education Standards (1996, 2000) and scientific practice in the recent Framework for K-12 Science Education (2011). In order to encourage student-centered science inquiry, teacher training utilizing GLOBE Atmosphere Investigations and GLOBE's Student Research Process are provided to middle and high school teachers to assist them in incorporating real scientific investigations into their classroom. Through participation in the program, teachers become a part of GLOBE (Global Learning and Observations to Benefit the Environment) - an international community of teachers, students, and scientists studying environmental science in over 24,000 schools around the world. The program uses NASA's satellites and the collection of atmosphere data by students to provide an engaging science learning experience for the students, and teachers. The GLOBE Atmosphere Investigations program offers year-long support to both teachers and students through direct involvement with NASA

  15. Kuwait poised for massive well kill effort

    Energy Technology Data Exchange (ETDEWEB)

    1991-04-08

    This paper reports that full scale efforts to extinguish Kuwait's oil well fires are to begin. The campaign to combat history's worst oil fires, originally expected to begin in mid-March, has been hamstrung by logistical problems, including delays in equipment deliveries caused by damage to Kuwait's infrastructure. Meantime, production from a key field off Kuwait--largely unaffected by the war--is expected to resume in May, but Kuwaiti oil exports will still be hindered by damaged onshore facilities. In addition, Kuwait is lining up equipment and personnel to restore production from its heavily damaged oil fields. Elsewhere in the Persian Gulf, Saudi Arabia reports progress in combating history's worst oil spills but acknowledges a continuing threat.

  16. Directed-energy process technology efforts

    Science.gov (United States)

    Alexander, P.

    1985-01-01

    A summary of directed-energy process technology for solar cells was presented. This technology is defined as directing energy or mass to specific areas on solar cells to produce a desired effect in contrast to exposing a cell to a thermal or mass flow environment. Some of these second generation processing techniques are: ion implantation; microwave-enhanced chemical vapor deposition; rapid thermal processing; and the use of lasers for cutting, assisting in metallization, assisting in deposition, and drive-in of liquid dopants. Advantages of directed energy techniques are: surface heating resulting in the bulk of the cell material being cooler and unchanged; better process control yields; better junction profiles, junction depths, and metal sintering; lower energy consumption during processing and smaller factory space requirements. These advantages should result in higher-efficiency cells at lower costs. The results of the numerous contracted efforts were presented as well as the application potentials of these new technologies.

  17. The European fusion nuclear technology effort

    International Nuclear Information System (INIS)

    Darvas, J.

    1989-01-01

    The role of fusion technology in the European fusion development strategy is outlined. The main thrust of the present fusion technology programme is responding to development needs of the Next European Torus. A smaller, but important and growing R and D effort is dealing with problems specific to the Demonstration, or Fusion Power, Reactor. The part of the programme falling under the somewhat arbitrarily defined category of 'fusion nuclear technology' is reviewed and an outlook to future activities is given. The review includes tritium technology, blanket technology and breeder materials development, technology and materials for the protection of the first wall and of other plasma facing components, remote handling technology, and safety and environmental impact studies. A few reflections are offered on the future long-term developments in fusion technology. (orig.)

  18. Peru continues to press privitization efforts

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    This paper reports that Peru has again extended the deadline for bids on a 30 year operating contract for state owned Petromar SA's offshore Block Z-2b. The tender is key to efforts to privatize Petromar, a subsidiary of state oil company Petroleos del Peru. The committee charged with implementing Petromar privatization extended the deadline for bids another 70 days Oct. 30, following a 60 day extension made in September. The latest deadline for bids is Feb. 10, with the contract expected to be awarded Feb. 26. A bid package on Block Z-2b is available from Petroperu's Lima headquarters for $20,000. Petromar operates the former Belco Petroleum Corp. offshore assets Peru's government expropriated in 1985. It currently produces 17,600 b/d, compared with 27,000 b/d at the time of expropriation

  19. The present gravitational wave detection effort

    International Nuclear Information System (INIS)

    Riles, Keith

    2010-01-01

    Gravitational radiation offers a new non-electromagnetic window through which to observe the universe. The LIGO and Virgo Collaborations have completed a first joint data run with unprecedented sensitivities to gravitational waves. Results from searches in the data for a variety of astrophysical sources are presented. A second joint data run with improved detector sensitivities is underway, and soon major upgrades will be carried out to build Advanced LIGO and Advanced Virgo with expected improvements in event rates of more than 1000. In parallel there is a vigorous effort in the radio pulsar community to detect nHz gravitational waves via the timing residuals in an array of pulsars at different locations in the sky.

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

    Science.gov (United States)

    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

  1. Superconducting cavities developments efforts at RRCAT

    International Nuclear Information System (INIS)

    Puntambekar, A.; Bagre, M.; Dwivedi, J.; Shrivastava, P.; Mundra, G.; Joshi, S.C.; Potukuchi, P.N.

    2011-01-01

    Superconducting RE cavities are the work-horse for many existing and proposed linear accelerators. Raja Ramanna Centre for Advanced Technology (RRCAT) has initiated a comprehensive R and D program for development of Superconducting RF cavities suitable for high energy accelerator application like SNS and ADS. For the initial phase of technology demonstration several prototype 1.3 GHz single cell-cavities have been developed. The work began with development of prototype single cell cavities in aluminum and copper. This helped in development of cavity manufacturing process, proving various tooling and learning on various mechanical and RF qualification processes. The parts manufacturing was done at RRCAT and Electron beam welding was carried out at Indian industry. These cavities further served during commissioning trials for various cavity processing infrastructure being developed at RRCAT and are also a potential candidate for Niobium thin film deposition R and D. Based on the above experience, few single cell cavities were developed in fine grain niobium. The critical technology of forming and machining of niobium and the intermediate RF qualification were developed at RRCAT. The EB welding of bulk niobium cavities was carried out in collaboration with IUAC, New Delhi at their facility. As a next logical step efforts are now on for development of multicell cavities. The prototype dumbbells and end group made of aluminium, comprising of RF and HOM couplers ports have also been developed, with their LB welding done at Indian industry. In this paper we shall present the development efforts towards manufacturing of 1.3 GHz single cell cavities and their initial processing and qualification. (author)

  2. Self-regulating the effortful "social dos".

    Science.gov (United States)

    Cortes, Kassandra; Kammrath, Lara K; Scholer, Abigail A; Peetz, Johanna

    2014-03-01

    In the current research, we explored differences in the self-regulation of the personal dos (i.e., engaging in active and effortful behaviors that benefit the self) and in the self-regulation of the social dos (engaging in those same effortful behaviors to benefit someone else). In 6 studies, we examined whether the same trait self-control abilities that predict task persistence on personal dos would also predict task persistence on social dos. That is, would the same behavior, such as persisting through a tedious and attentionally demanding task, show different associations with trait self-control when it is framed as benefitting the self versus someone else? In Studies 1-3, we directly compared the personal and social dos and found that trait self-control predicted self-reported and behavioral personal dos but not social dos, even when the behaviors were identical and when the incentives were matched. Instead, trait agreeableness--a trait linked to successful self-regulation within the social domain--predicted the social dos. Trait self-control did not predict the social dos even when task difficulty increased (Study 4), but it did predict the social don'ts, consistent with past research (Studies 5-6). The current studies provide support for the importance of distinguishing different domains of self-regulated behaviors and suggest that social dos can be successfully performed through routes other than traditional self-control abilities. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

  3. Standardization efforts of digital pathology in Europe.

    Science.gov (United States)

    Rojo, Marcial García; Daniel, Christel; Schrader, Thomas

    2012-01-01

    EURO-TELEPATH is a European COST Action IC0604. It started in 2007 and will end in November 2011. Its main objectives are evaluating and validating the common technological framework and communication standards required to access, transmit, and manage digital medical records by pathologists and other medical specialties in a networked environment. Working Group 1, "Business Modelling in Pathology," has designed main pathology processes - Frozen Study, Formalin Fixed Specimen Study, Telepathology, Cytology, and Autopsy - using Business Process Modelling Notation (BPMN). Working Group 2 has been dedicated to promoting the application of informatics standards in pathology, collaborating with Integrating Healthcare Enterprise (IHE), Digital Imaging and Communications in Medicine (DICOM), Health Level Seven (HL7), and other standardization bodies. Health terminology standardization research has become a topic of great interest. Future research work should focus on standardizing automatic image analysis and tissue microarrays imaging.

  4. Effort, anhedonia, and function in schizophrenia: reduced effort allocation predicts amotivation and functional impairment.

    Science.gov (United States)

    Barch, Deanna M; Treadway, Michael T; Schoen, Nathan

    2014-05-01

    One of the most debilitating aspects of schizophrenia is an apparent interest in or ability to exert effort for rewards. Such "negative symptoms" may prevent individuals from obtaining potentially beneficial outcomes in educational, occupational, or social domains. In animal models, dopamine abnormalities decrease willingness to work for rewards, implicating dopamine (DA) function as a candidate substrate for negative symptoms given that schizophrenia involves dysregulation of the dopamine system. We used the effort-expenditure for rewards task (EEfRT) to assess the degree to which individuals with schizophrenia were wiling to exert increased effort for either larger magnitude rewards or for rewards that were more probable. Fifty-nine individuals with schizophrenia and 39 demographically similar controls performed the EEfRT task, which involves making choices between "easy" and "hard" tasks to earn potential rewards. Individuals with schizophrenia showed less of an increase in effort allocation as either reward magnitude or probability increased. In controls, the frequency of choosing the hard task in high reward magnitude and probability conditions was negatively correlated with depression severity and anhedonia. In schizophrenia, fewer hard task choices were associated with more severe negative symptoms and worse community and work function as assessed by a caretaker. Consistent with patterns of disrupted dopamine functioning observed in animal models of schizophrenia, these results suggest that 1 mechanism contributing to impaired function and motivational drive in schizophrenia may be a reduced allocation of greater effort for higher magnitude or higher probability rewards.

  5. Mixed Connective Tissue Disease

    Science.gov (United States)

    Mixed connective tissue disease Overview Mixed connective tissue disease has signs and symptoms of a combination of disorders — primarily lupus, scleroderma and polymyositis. For this reason, mixed connective tissue disease ...

  6. Undifferentiated Connective Tissue Disease

    Science.gov (United States)

    ... Home Conditions Undifferentiated Connective Tissue Disease (UCTD) Undifferentiated Connective Tissue Disease (UCTD) Make an Appointment Find a Doctor ... by Barbara Goldstein, MD (February 01, 2016) Undifferentiated connective tissue disease (UCTD) is a systemic autoimmune disease. This ...

  7. Soft Tissue Sarcoma

    Science.gov (United States)

    ... muscles, tendons, fat, and blood vessels. Soft tissue sarcoma is a cancer of these soft tissues. There ... have certain genetic diseases. Doctors diagnose soft tissue sarcomas with a biopsy. Treatments include surgery to remove ...

  8. Engineering complex orthopaedic tissues via strategic biomimicry.

    Science.gov (United States)

    Qu, Dovina; Mosher, Christopher Z; Boushell, Margaret K; Lu, Helen H

    2015-03-01

    The primary current challenge in regenerative engineering resides in the simultaneous formation of more than one type of tissue, as well as their functional assembly into complex tissues or organ systems. Tissue-tissue synchrony is especially important in the musculoskeletal system, wherein overall organ function is enabled by the seamless integration of bone with soft tissues such as ligament, tendon, or cartilage, as well as the integration of muscle with tendon. Therefore, in lieu of a traditional single-tissue system (e.g., bone, ligament), composite tissue scaffold designs for the regeneration of functional connective tissue units (e.g., bone-ligament-bone) are being actively investigated. Closely related is the effort to re-establish tissue-tissue interfaces, which is essential for joining these tissue building blocks and facilitating host integration. Much of the research at the forefront of the field has centered on bioinspired stratified or gradient scaffold designs which aim to recapitulate the structural and compositional inhomogeneity inherent across distinct tissue regions. As such, given the complexity of these musculoskeletal tissue units, the key question is how to identify the most relevant parameters for recapitulating the native structure-function relationships in the scaffold design. Therefore, the focus of this review, in addition to presenting the state-of-the-art in complex scaffold design, is to explore how strategic biomimicry can be applied in engineering tissue connectivity. The objective of strategic biomimicry is to avoid over-engineering by establishing what needs to be learned from nature and defining the essential matrix characteristics that must be reproduced in scaffold design. Application of this engineering strategy for the regeneration of the most common musculoskeletal tissue units (e.g., bone-ligament-bone, muscle-tendon-bone, cartilage-bone) will be discussed in this review. It is anticipated that these exciting efforts will

  9. Engineering Complex Orthopaedic Tissues via Strategic Biomimicry

    Science.gov (United States)

    Qu, Dovina; Mosher, Christopher Z.; Boushell, Margaret K.; Lu, Helen H.

    2014-01-01

    The primary current challenge in regenerative engineering resides in the simultaneous formation of more than one type of tissue, as well as their functional assembly into complex tissues or organ systems. Tissue-tissue synchrony is especially important in the musculoskeletal system, whereby overall organ function is enabled by the seamless integration of bone with soft tissues such as ligament, tendon, or cartilage, as well as the integration of muscle with tendon. Therefore, in lieu of a traditional single-tissue system (e.g. bone, ligament), composite tissue scaffold designs for the regeneration of functional connective tissue units (e.g. bone-ligament-bone) are being actively investigated. Closely related is the effort to re-establish tissue-tissue interfaces, which is essential for joining these tissue building blocks and facilitating host integration. Much of the research at the forefront of the field has centered on bioinspired stratified or gradient scaffold designs which aim to recapitulate the structural and compositional inhomogeneity inherent across distinct tissue regions. As such, given the complexity of these musculoskeletal tissue units, the key question is how to identify the most relevant parameters for recapitulating the native structure-function relationships in the scaffold design. Therefore, the focus of this review, in addition to presenting the state-of-the-art in complex scaffold design, is to explore how strategic biomimicry can be applied in engineering tissue connectivity. The objective of strategic biomimicry is to avoid over-engineering by establishing what needs to be learned from nature and defining the essential matrix characteristics that must be reproduced in scaffold design. Application of this engineering strategy for the regeneration of the most common musculoskeletal tissue units (e.g. bone-ligament-bone, muscle-tendon-bone, cartilage-bone) will be discussed in this review. It is anticipated that these exciting efforts will

  10. Neighbourhood social and built environment factors and falls in community-dwelling canadian older adults: A validation study and exploration of structural confounding

    Directory of Open Access Journals (Sweden)

    Afshin Vafaei

    2016-12-01

    Full Text Available Older persons are vulnerable to the ill effects of their social and built environment due to age-related limitations in mobility and bio-psychological vulnerability. Falls are common in older adults and result from complex interactions between individual, social, and contextual determinants. We addressed two methodological issues of neighbourhood-health and social epidemiological studies in this analysis: (1 validity of measures of neighbourhood contexts, and (2 structural confounding resulting from social sorting mechanisms. Baseline data from International Mobility in Aging Study were used. Samples included community-dwelling Canadians older than 65 living in Kingston (Ontario and St-Hyacinthe (Quebec. We performed factor analysis and ecometric analysis to assess the validity of measures of neighbourhood social capital, socioeconomic status, and the built environment and stratified tabular analyses to explore structural confounding. The scales all demonstrated good psychometric and ecometric properties. There was an evidence of the existence of structural confounding in this sample of Canadian older adults as some combinations of strata for the three neighbourhood measures had no population. This limits causal inference in studying relationships between neighbourhood factors and falls and should be taken into account in aetiological aging research. Keywords: Ecometric analysis, Falls, Social and built environment, Neighbourhoods, Older adults, Social Capital, Structural confounding, Validity

  11. Effects of categorization method, regression type, and variable distribution on the inflation of Type-I error rate when categorizing a confounding variable.

    Science.gov (United States)

    Barnwell-Ménard, Jean-Louis; Li, Qing; Cohen, Alan A

    2015-03-15

    The loss of signal associated with categorizing a continuous variable is well known, and previous studies have demonstrated that this can lead to an inflation of Type-I error when the categorized variable is a confounder in a regression analysis estimating the effect of an exposure on an outcome. However, it is not known how the Type-I error may vary under different circumstances, including logistic versus linear regression, different distributions of the confounder, and different categorization methods. Here, we analytically quantified the effect of categorization and then performed a series of 9600 Monte Carlo simulations to estimate the Type-I error inflation associated with categorization of a confounder under different regression scenarios. We show that Type-I error is unacceptably high (>10% in most scenarios and often 100%). The only exception was when the variable categorized was a continuous mixture proxy for a genuinely dichotomous latent variable, where both the continuous proxy and the categorized variable are error-ridden proxies for the dichotomous latent variable. As expected, error inflation was also higher with larger sample size, fewer categories, and stronger associations between the confounder and the exposure or outcome. We provide online tools that can help researchers estimate the potential error inflation and understand how serious a problem this is. Copyright © 2014 John Wiley & Sons, Ltd.

  12. Slow growth efforts renewed in Iran.

    Science.gov (United States)

    Aghajanian, A

    1992-10-01

    Iran's first population policy was developed under the Shah in 1967. Policymakers brought in with the Islamic Revolution of 1979, however, rejected much of the earlier regime's views on women and childbearing. During the Iran-Iraq war of 1980-88, large population size and rapid growth were seen as advantageous to the war effort. After the war, the government of Iran again began to voice concern about rapid population growth. The pragmatic and proactive approach taken by the government since 1988 may, indeed, accelerate a decline in fertility began in the late 1960s, but stalled in the 1980s. The following are examples of the new governmental attitude: the Iranian government announced March 1992 that it would begin importing Norplant and make it available along with other contraceptives at public clinics; last year, the government announced that the fourth child of a family would not be eligible for food rationing or nutritional supplements and other public child benefits; the Minister of Health in 1991 for the first time publicly encouraged male sterilization; and last fall, Iran conducted a special census of the population five years before the regular decennial census date of 1996. These actions represent dramatic policy changes on population growth and family planning in this country of 60 million, the largest and one of the fastest growing in the Middle East.

  13. NREL Quickens its Tech Transfer Efforts

    Energy Technology Data Exchange (ETDEWEB)

    Lammers, H.

    2012-02-01

    Innovations and 'aha' movements in renewable energy and energy efficiency, while exciting in the lab, only truly live up to their promise once they find a place in homes or business. Late last year President Obama issued a directive to all federal agencies to increase their efforts to transfer technologies to the private sector in order to achieve greater societal and economic impacts of federal research investments. The president's call to action includes efforts to establish technology transfer goals and to measure progress, to engage in efforts to increase the speed of technology transfer and to enhance local and regional innovation partnerships. But, even before the White House began its initiative to restructure the commercialization process, the National Renewable Energy Laboratory had a major effort underway designed to increase the speed and impact of technology transfer activities and had already made sure its innovations had a streamlined path to the private sector. For the last three years, NREL has been actively setting commercialization goals and tracking progress against those goals. For example, NREL sought to triple the number of innovations over a five-year period that began in 2009. Through best practices associated with inventor engagement, education and collaboration, NREL quadrupled the number of innovations in just three years. Similar progress has been made in patenting, licensing transactions, income generation and rewards to inventors. 'NREL is known nationally for our cutting-edge research and companies know to call us when they are ready to collaborate,' William Farris, vice president for commercialization and technology transfer, said. 'Once a team is ready to dive in, they don't want be mired in paperwork. We've worked to make our process for licensing NREL technology faster; it now takes less than 60 days for us to come to an agreement and start work with a company interested in our research

  14. ICRP new recommendations. Committee 2's efforts

    International Nuclear Information System (INIS)

    Eckerman, K.F.

    2007-01-01

    The International Commission on Radiological Protection (ICRP) may release new primary radiation protection recommendation in 2007. Committee 2 has underway reviews of the dosimetric and biokinetic models and associated data used in calculating dose coefficients for intakes of radionuclides and exposures to external radiation fields. This paper outlines the work plans of Committee 2 during the current term, 2005-2009, in anticipation of the new primary recommendations. The two task groups of Committee 2 responsible for the computations of dose coefficients, INDOS and DOCAL, are reviewing the models and data used in the computations. INDOS is reviewing the lung model and the biokinetic models that describe the behavior of the radionuclides in the body. DOCAL is reviewing its computational formulations with the objective of harmonizing the formulation with those of nuclear medicine, and developing new computational phantoms representing the adult male and female reference individuals of ICRP Publication 89. In addition, DOCAL will issue a publication on nuclear decay data to replace ICRP Publication 38. While the current efforts are focused on updating the dose coefficients for occupational intakes of radionuclides plans are being formulated to address dose coefficients for external radiation fields which include consideration of high energy fields associated with accelerators and space travel and the updating of dose coefficients for members of the public. (author)

  15. STEM Education Efforts in the Ares Projects

    Science.gov (United States)

    Doreswamy, Rajiv; Armstrong, Robert C.

    2010-01-01

    According to the National Science Foundation, of the more than 4 million first university degrees awarded in science and engineering in 2006, students in China earned about 21%, those in the European Union earned about 19%, and those in the United States earned about 11%. Statistics like these are of great interest to NASA's Ares Projects, which are responsible for building the rockets for the U.S. Constellation Program to send humans beyond low-Earth orbit. Science, technology, engineering, and mathematics students are essential for the long-term sustainability of any space program. Since the Projects creation, the Ares Outreach Team has used a variety of STEM-related media, methods, and materials to engage students, educators, and the general public in Constellation's mission. Like Project Apollo, the nation s exploration destinations and the vehicles used to get there can inspire students to learn more about STEM. Ares has been particularly active in public outreach to schools in Northern Alabama; on the Internet via outreach and grade-specific educational materials; and in more informal social media settings such as YouTube and Facebook. These combined efforts remain integral to America s space program, regardless of its future direction.

  16. Regionally Applied Research Efforts (RARE) Report titled " ...

    Science.gov (United States)

    The traditional methodology for health risk assessment used by the U. S. Environmental Protection Agency (EPA) is based on the use of exposure assumptions (e.g. exposure duration, food ingestion rate, body weight, etc.) that represent the entire American population, either as a central tendency exposure (e.g. average, median) or as a reasonable maximum exposure (e.g. 95% upper confidence limit). Unfortunately, EPA lacked exposure information for assessing health risks for New England regional tribes sustaining a tribal subsistence way of life. As a riverine tribe, the Penobscot culture and traditions are inextricably tied to the Penobscot River watershed. It is through hunting, fishing, trapping, gathering and making baskets, pottery, moccasins, birch-bark canoes and other traditional practices that the Penobscot culture and people are sustained. The Penobscot River receives a variety of pollutant discharges leaving the Penobscot Indian Nation (PIN) questioning the ecological health and water quality of the river and how this may affect the practices that sustain their way of life. The objectives of this Regional Applied Research Effort (RARE) study were to: (1) Develop culturally sensitive methodologies for assessing the potential level of exposure to contaminants that Penobscot Indian Nation tribal members may have from maintaining tribal sustenance practices; (2) Conduct field surveys and laboratory analysis on targeted flora and fauna for chemical expo

  17. Differential recall bias, intermediate confounding, and mediation analysis in life course epidemiology: An analytic framework with empirical example.

    Directory of Open Access Journals (Sweden)

    Mashhood Ahmed Sheikh

    2016-11-01

    Full Text Available The mechanisms by which childhood socioeconomic status (CSES affects adult mental health, general health, and well-being are not clear. Moreover, the analytical assumptions employed when assessing mediation in social and psychiatric epidemiology are rarely explained. The aim of this paper was to explain the intermediate confounding assumption, and to quantify differential recall bias in the association between CSES, childhood abuse, and mental health (SCL-10, general health (EQ-5D, and subjective well-being (SWLS. Furthermore, we assessed the mediating role of psychological and physical abuse in the association between CSES and mental health, general health, and well-being; and the influence of differential recall bias in the estimation of total effects, direct effects, and proportion of mediated effects. The assumptions employed when assessing mediation are explained with reference to a causal diagram. Poisson regression models (relative risk, RR and 99% CI were used to assess the association between CSES and psychological and physical abuse in childhood. Mediation analysis (difference method was used to assess the indirect effect of CSES (through psychological and physical abuse in childhood on mental health, general health, and well-being. Psychological abuse and physical abuse mediated the association between CSES and adult mental health, general health, and well-being (6-16% among men and 7-14% among women, p<0.001. The results suggest that up to 27% of the association between CSES and childhood abuse, 23% of the association between childhood abuse, and mental health, general health, and well-being, and 44% of the association between CSES and mental health, general health, and well-being is driven by differential recall bias. Assessing mediation with cross-sectional data (exposure, mediator, and outcome measured at the same time showed that the total effects and direct effects were vastly overestimated (biased upwards. Consequently, the

  18. The confounding of race and geography: how much of the excess stroke mortality among African Americans is explained by geography?

    Science.gov (United States)

    Yang, Dongyan; Howard, George; Coffey, Christopher S; Roseman, Jeffrey

    2004-01-01

    The excess stroke mortality among African Americans and Southerners is well known. Because a higher proportion of the population living in the 'Stroke Belt' is African American, then a portion of the estimated excess risk of stroke death traditionally associated with African-American race may be attributable to geography (i.e., race and geography are 'confounded'). In this paper we estimate the proportion of the excess stroke mortality among African Americans that is attributable to geography. The numbers of stroke deaths at the county level are available from the vital statistics system of the US. A total of 1,143 counties with a population of at least 500 whites and 500 African Americans were selected for these analyses. The black-to-white stroke mortality ratio was estimated with and without adjustment for county of residence for those aged 45-64 and for those aged 65 and over. The difference in the stroke mortality ratio before versus after adjustment for county provides an estimate of the proportion of the excess stroke mortality inappropriately attributed to race (that is in fact attributable to geographic region). For ages 45-64, the black-to-white stroke mortality ratio was reduced from 3.41 to 3.04 for men, and from 2.82 to 2.60 for women, suggesting that between 10 and 15% of the excess mortality traditionally attributed to race is rather due to geography. Over the age of 65, the black-to-white stroke mortality ratio was reduced from 1.31 to 1.27 for men, and from 1.097 to 1.095 for women, suggesting that between 2 and 13% of the excess mortality attributed to black race is actually attributable to geography. The reductions of all the four age strata gender groups were highly significant. These results suggest that a significant, although relatively small, proportion of the excess mortality traditionally attributed to race is rather a factor of geography. Copyright 2004 S. Karger AG, Basel

  19. A Comprehensive Analysis of the SRS-Schwab Adult Spinal Deformity Classification and Confounding Variables: A Prospective, Non-US Cross-sectional Study in 292 Patients.

    Science.gov (United States)

    Hallager, Dennis Winge; Hansen, Lars Valentin; Dragsted, Casper Rokkjær; Peytz, Nina; Gehrchen, Martin; Dahl, Benny

    2016-05-01

    Cross-sectional analyses on a consecutive, prospective cohort. To evaluate the ability of the Scoliosis Research Society (SRS)-Schwab Adult Spinal Deformity Classification to group patients by widely used health-related quality-of-life (HRQOL) scores and examine possible confounding variables. The SRS-Schwab Adult Spinal Deformity Classification includes sagittal modifiers considered important for HRQOL and the clinical impact of the classification has been validated in patients from the International Spine Study Group database; however, equivocal results were reported for the Pelvic Tilt modifier and potential confounding variables were not evaluated. Between March 2013 and May 2014, all adult spinal deformity patients from our outpatient clinic with sufficient radiographs were prospectively enrolled. Analyses of HRQOL variance and post hoc analyses were performed for each SRS-Schwab modifier. Age, history of spine surgery, and aetiology of spinal deformity were considered potential confounders and their influence on the association between SRS-Schwab modifiers and aggregated Oswestry Disability Index (ODI) scores was evaluated with multivariate proportional odds regressions. P values were adjusted for multiple testing. Two hundred ninety-two of 460 eligible patients were included for analyses. The SRS-Schwab Classification significantly discriminated HRQOL scores between normal and abnormal sagittal modifier classifications. Individual grade comparisons showed equivocal results; however, Pelvic Tilt grade + versus +  + did not discriminate patients according to any HRQOL score. All modifiers showed significant proportional odds for worse aggregated ODI scores with increasing grade levels and the effects were robust to confounding. However, age group and aetiology had individual significant effects. The SRS-Schwab sagittal modifiers reliably grouped patients graded 0 versus + / +  + according to the most widely used HRQOL scores and the

  20. Quality-oriented efforts in IPD, - a framework

    DEFF Research Database (Denmark)

    Andreasen, Mogens Myrup

    1998-01-01

    It is generally expected that modern quality efforts like TQM and ISO9000 should deliver a sufficient framework for quality efforts in industrial companies. Our findings in Danish industry shows a fragmented picture of islands of efforts and a weak understanding of basic quality concepts between...... designers. The paper propose a framework for quality efforts, illustrated by simple metaphors....

  1. IAEA Patient Protection Effort Reaches Key Milestone

    International Nuclear Information System (INIS)

    2012-01-01

    Full text: An International Atomic Energy Agency (IAEA) effort to help people track their radiation exposure from medical procedures achieved a significant milestone this week. The Agency received the final approval from a group of medical oversight organizations for the 'Joint Position Statement on the IAEA Patient Radiation Exposure Tracking', a set of principles to guide patient protection efforts at the sub-national, national, and international level. The joint statement endorses the IAEA's three-year-old Smart Card/SmartRadTrack project, which aims to help nations develop systems to track medical radiation procedures and radiation doses. The statement has been agreed by the World Health Organization (WHO), the U.S. Food and Drug Administration (FDA), the European Society of Radiology (ESR), the International Organization for Medical Physics (IOMP), the International Society of Radiographers and Radiological Technologists (ISRRT), and the Conference of Radiation Control Program Directors, USA (CRCPD). 'This system is critical if the medical community is going to keep patients safe when they are being referred for more and more diagnostic scans. These scans, over the years, are made using more and more powerful machines', said Madan Rehani, Radiation Safety Specialist in the IAEA's Radiation Protection of Patients Unit. 'The tracking system will draw doctors' attention to previous radiological examinations, both in terms of clinical information and radiation dose and thus help them assess whether the 11th or 20th CT scan is really appropriate, whether it will do more good than harm.' Advances in radiation-based diagnostic technologies, such as the CT scan, have led to patients receiving such procedures more frequently. The convenience of CT with the added advantage of increased information has resulted in increased usage to the point that there are instances of patients getting tens of CT scans in a few years, not all of which may be justified, or getting CT

  2. 1996 Design effort for IFMIF HEBT

    International Nuclear Information System (INIS)

    Blind, B.

    1997-01-01

    The paper details the 1996 design effort for the IFMIF HEBT. Following a brief overview, it lists the primary requirements for the beam at the target, describes the design approach and design tools used, introduces the beamline modules, gives the results achieved with the design at this stage, points out possible improvements and gives the names and computer locations of the TRACE3-D and PARMILA files that sum up the design work. The design does not fully meet specifications in regards to the flatness of the distribution at the target. With further work, including if necessary some backup options, the flatness specifications may be realized. It is not proposed that the specifications, namely flatness to ±5% and higher-intensity ridges that are no more than 15% above average, be changed at this time. The design also does not meet the requirement that the modules of all beamlines should operate at the same settings. However, the goal of using identical components and operational procedures has been met and only minor returning is needed to produce very similar beam distributions from all beamlines. Significant further work is required in the following areas: TRACE3-D designs and PARMILA runs must be made for the beams coming from accelerators No. 3 and No. 4. Transport of 30-MeV and 35-MeV beams to the targets and beam dump must be studied. Comprehensive error studies must be made. These must result in tolerance specifications and may require design iterations. Detailed interfacing with target-spot instrumentation is required. This instrumentation must be able to check all aspects of the specifications

  3. Manager's effort and endogenous economic discrimination

    Directory of Open Access Journals (Sweden)

    Jaime Orrillo

    2004-09-01

    Full Text Available Assume a labor supply consisting of two types of workers, 1 and 2. Both workers are equally productive and exhibit supply functions with the same elasticity. We consider a firm (entrepreneur or shareholders that is competitive in the output market and monopsonistic in input markets. The firm uses the services of a manager who has a high human capital and whose wage is given by the market. It is supposed that the manager does not like to work with one type of worker, say type 1. If we allow the manager's effort to be an additional input without any extra (in addition to his salary cost for the firm, then the firm's pricing decision will be different for both workers. That is, there will be a wage differential and therefore endogenous economic discrimination2 in the labor markets.Vamos assumir que a oferta de trabalho consiste de dois tipos de trabalhadores, 1 e 2. Ambos os trabalhadores são igualmente produtivos e exibem funções de oferta com a mesma elasticidade. Consideramos uma firma (empresário ou acionistas, a qual é competitiva no mercado de produtos e monopsonista nos mercados de insumos. A firma usa os serviços de um gerente quem tem um alto capital humano e cujo salário é dado pelo mercado. Suponhamos que o gerente não gosta de trabalhar com um tipo de trabalhador, digamos o tipo 1. Se permitirmos que o esforço do gerente seja um insumo adicional sem nenhum custo extra (além de seu salário, a decisão de salários será diferente para ambos os trabalhadores. Isto é, haverá um diferencial de salários e, em conseqüência, uma discriminação econômica1 endógena nos mercados de trabalho.

  4. Tissue bionics: examples in biomimetic tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Green, David W [Bone and Joint Research Group, Developmental Origins of Health and Disease, General Hospital, University of Southampton, SO16 6YD (United Kingdom)], E-mail: Hindoostuart@googlemail.com

    2008-09-01

    Many important lessons can be learnt from the study of biological form and the functional design of organisms as design criteria for the development of tissue engineering products. This merging of biomimetics and regenerative medicine is termed 'tissue bionics'. Clinically useful analogues can be generated by appropriating, modifying and mimicking structures from a diversity of natural biomatrices ranging from marine plankton shells to sea urchin spines. Methods in biomimetic materials chemistry can also be used to fabricate tissue engineering scaffolds with added functional utility that promise human tissues fit for the clinic.

  5. Tissue bionics: examples in biomimetic tissue engineering

    International Nuclear Information System (INIS)

    Green, David W

    2008-01-01

    Many important lessons can be learnt from the study of biological form and the functional design of organisms as design criteria for the development of tissue engineering products. This merging of biomimetics and regenerative medicine is termed 'tissue bionics'. Clinically useful analogues can be generated by appropriating, modifying and mimicking structures from a diversity of natural biomatrices ranging from marine plankton shells to sea urchin spines. Methods in biomimetic materials chemistry can also be used to fabricate tissue engineering scaffolds with added functional utility that promise human tissues fit for the clinic

  6. Comparison of cardiovascular response to combined static-dynamic effort, postprandial dynamic effort and dynamic effort alone in patients with chronic ischemic heart disease

    International Nuclear Information System (INIS)

    Hung, J.; McKillip, J.; Savin, W.; Magder, S.; Kraus, R.; Houston, N.; Goris, M.; Haskell, W.; DeBusk, R.

    1982-01-01

    The cardiovascular responses to combined static-dynamic effort, postprandial dynamic effort and dynamic effort alone were evaluated by upright bicycle ergometry during equilibrium-gated blood pool scintigraphy in 24 men, mean age 59 +/- 8 years, with chronic ischemic heart disease. Combined static-dynamic effort and the postprandial state elicited a peak cardiovascular response similar to that of dynamic effort alone. Heart rate, intraarterial systolic and diastolic pressures, rate-pressure product and ejection fraction were similar for the three test conditions at the onset of ischemia and at peak effort. The prevalence and extent of exercise-induced ischemic left ventricular dysfunction, ST-segment depression, angina pectoris and ventricular ectopic activity were also similar during the three test conditions. Direct and indirect measurements of systolic and diastolic blood pressure were highly correlated. The onset of ischemic ST-segment depression and angina pectoris correlated as strongly with heart rate alone as with the rate-pressure product during all three test conditions. The cardiovascular response to combined static-dynamic effort and to postprandial dynamic effort becomes more similar to that of dynamic effort alone as dynamic effort reaches a symptom limit. If significant ischemic and arrhythmic abnormalities are absent during symptom-limited dynamic exercise testing, they are unlikely to appear during combined static-dynamic or postprandial dynamic effort

  7. Effort/reward imbalance and sedentary lifestyle: an observational study in a large occupational cohort.

    Science.gov (United States)

    Kouvonen, A; Kivimäki, M; Elovainio, M; Pentti, J; Linna, A; Virtanen, M; Vahtera, J

    2006-06-01

    To investigate the association between effort/reward imbalance (ERI) at work and sedentary lifestyle. Cross sectional data from the ongoing Finnish Public Sector Study related to 30,433 women and 7718 men aged 17-64 were used (n = 35,918 after exclusion of participants with missing values in covariates). From the responses to a questionnaire, an aggregated mean score for ERI in a work unit was assigned to each participant. The outcome was sedentary lifestyle defined as work unit level predictors in the models. Adjustments were made for age, marital status, occupational status, job contract, smoking, and heavy drinking. Twenty five per cent of women and 27% of men had a sedentary lifestyle. High individual level ERI was associated with a higher likelihood of sedentary lifestyle both among women (odds ratio (OR) = 1.08, 95% CI 1.01 to 1.16) and men (OR = 1.17, 95% CI 1.02 to 1.33). These associations were not explained by relevant confounders and they were also independent of work unit level job strain measured as a ratio of job demands and control. A mismatch between high occupational effort spent and low reward received in turn seems to be associated with an increased risk of sedentary lifestyle, although this association is relatively weak.

  8. Effort/reward imbalance and sedentary lifestyle: an observational study in a large occupational cohort

    Science.gov (United States)

    Kouvonen, A; Kivimäki, M; Elovainio, M; Pentti, J; Linna, A; Virtanen, M; Vahtera, J

    2006-01-01

    Objectives To investigate the association between effort/reward imbalance (ERI) at work and sedentary lifestyle. Methods Cross sectional data from the ongoing Finnish Public Sector Study related to 30 433 women and 7718 men aged 17–64 were used (n = 35 918 after exclusion of participants with missing values in covariates). From the responses to a questionnaire, an aggregated mean score for ERI in a work unit was assigned to each participant. The outcome was sedentary lifestyle defined as sedentary lifestyle. High individual level ERI was associated with a higher likelihood of sedentary lifestyle both among women (odds ratio (OR) = 1.08, 95% CI 1.01 to 1.16) and men (OR = 1.17, 95% CI 1.02 to 1.33). These associations were not explained by relevant confounders and they were also independent of work unit level job strain measured as a ratio of job demands and control. Conclusions A mismatch between high occupational effort spent and low reward received in turn seems to be associated with an increased risk of sedentary lifestyle, although this association is relatively weak. PMID:16497854

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

    Directory of Open Access Journals (Sweden)

    Marshall, M. R.

    2004-06-01

    Full Text Available 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

  10. Raman Spectroscopy of Ocular Tissue

    Science.gov (United States)

    Ermakov, Igor V.; Sharifzadeh, Mohsen; Gellermann, Warner

    The optically transparent nature of the human eye has motivated numerous Raman studies aimed at the non-invasive optical probing of ocular tissue components critical to healthy vision. Investigations include the qualitative and quantitative detection of tissue-specific molecular constituents, compositional changes occurring with development of ocular pathology, and the detection and tracking of ocular drugs and nutritional supplements. Motivated by a better understanding of the molecular mechanisms leading to cataract formation in the aging human lens, a great deal of work has centered on the Raman detection of proteins and water content in the lens. Several protein groups and the hydroxyl response are readily detectable. Changes of protein compositions can be studied in excised noncataractous tissue versus aged tissue preparations as well as in tissue samples with artificially induced cataracts. Most of these studies are carried out in vitro using suitable animal models and conventional Raman techniques. Tissue water content plays an important role in optimum light transmission of the outermost transparent ocular structure, the cornea. Using confocal Raman spectroscopy techniques, it has been possible to non-invasively measure the water to protein ratio as a measure of hydration status and to track drug-induced changes of the hydration levels in the rabbit cornea at various depths. The aqueous humor, normally supplying nutrients to cornea and lens, has an advantageous anterior location for Raman studies. Increasing efforts are pursued to non-invasively detect the presence of glucose and therapeutic concentrations of antibiotic drugs in this medium. In retinal tissue, Raman spectroscopy proves to be an important tool for research into the causes of macular degeneration, the leading cause of irreversible vision disorders and blindness in the elderly. It has been possible to detect the spectral features of advanced glycation and advanced lipooxydation end products in

  11. Environmental regulation of valvulogenesis:implications for tissue engineering

    NARCIS (Netherlands)

    Riem Vis, P.W.; Kluin, J.; Sluijter, J.P.G.; Herwerden, van L.A.; Bouten, C.V.C.

    2011-01-01

    Ongoing research efforts aim at improving the creation of tissue-engineered heart valves for in vivo systemic application. Hence, in vitro studies concentrate on optimising culture protocols incorporating biological as well as biophysical stimuli for tissue development. Important lessons can be

  12. Effort-Reward Imbalance at Work and Incident Coronary Heart Disease: A Multicohort Study of 90,164 Individuals.

    Science.gov (United States)

    Dragano, Nico; Siegrist, Johannes; Nyberg, Solja T; Lunau, Thorsten; Fransson, Eleonor I; Alfredsson, Lars; Bjorner, Jakob B; Borritz, Marianne; Burr, Hermann; Erbel, Raimund; Fahlén, Göran; Goldberg, Marcel; Hamer, Mark; Heikkilä, Katriina; Jöckel, Karl-Heinz; Knutsson, Anders; Madsen, Ida E H; Nielsen, Martin L; Nordin, Maria; Oksanen, Tuula; Pejtersen, Jan H; Pentti, Jaana; Rugulies, Reiner; Salo, Paula; Schupp, Jürgen; Singh-Manoux, Archana; Steptoe, Andrew; Theorell, Töres; Vahtera, Jussi; Westerholm, Peter J M; Westerlund, Hugo; Virtanen, Marianna; Zins, Marie; Batty, G David; Kivimäki, Mika

    2017-07-01

    Epidemiologic evidence for work stress as a risk factor for coronary heart disease is mostly based on a single measure of stressful work known as job strain, a combination of high demands and low job control. We examined whether a complementary stress measure that assesses an imbalance between efforts spent at work and rewards received predicted coronary heart disease. This multicohort study (the "IPD-Work" consortium) was based on harmonized individual-level data from 11 European prospective cohort studies. Stressful work in 90,164 men and women without coronary heart disease at baseline was assessed by validated effort-reward imbalance and job strain questionnaires. We defined incident coronary heart disease as the first nonfatal myocardial infarction or coronary death. Study-specific estimates were pooled by random effects meta-analysis. At baseline, 31.7% of study members reported effort-reward imbalance at work and 15.9% reported job strain. During a mean follow-up of 9.8 years, 1,078 coronary events were recorded. After adjustment for potential confounders, a hazard ratio of 1.16 (95% confidence interval, 1.00-1.35) was observed for effort-reward imbalance compared with no imbalance. The hazard ratio was 1.16 (1.01-1.34) for having either effort-reward imbalance or job strain and 1.41 (1.12-1.76) for having both these stressors compared to having neither effort-reward imbalance nor job strain. Individuals with effort-reward imbalance at work have an increased risk of coronary heart disease, and this appears to be independent of job strain experienced. These findings support expanding focus beyond just job strain in future research on work stress.

  13. Adipose tissue Fatty Acid patterns and changes in antrhropometry

    DEFF Research Database (Denmark)

    Dahm, Christina Catherine; Gorst-Rasmussen, Anders; Jakobsen, Marianne Uhre

    2011-01-01

    Introduction Diets rich in n-3 long chain polyunsaturated fatty acids (LC-PUFA), but low in n-6 LC-PUFA and 18:1 trans-fatty acids (TFA), may lower the risk of overweight and obesity. These fatty acids have often been investigated individually. We explored associations between global patterns...... in adipose tissue fatty acids and changes in anthropometry. Methods 34 fatty acid species from adipose tissue biopsies were determined in a random sample of 1100 men and women from a Danish cohort study. We used sex-specific principal component analysis and multiple linear regression to investigate...... the associations of adipose tissue fatty acid patterns with changes in weight, waist circumference (WC), and WC controlled for changes in body mass index (WCBMI), adjusting for confounders. Results 7 principal components were extracted for each sex, explaining 77.6% and 78.3% of fatty acid variation in men...

  14. Desire thinking as a confounder in the relationship between mindfulness and craving: Evidence from a cross-cultural validation of the Desire Thinking Questionnaire.

    Science.gov (United States)

    Chakroun-Baggioni, Nadia; Corman, Maya; Spada, Marcantonio M; Caselli, Gabriele; Gierski, Fabien

    2017-10-01

    Desire thinking and mindfulness have been associated with craving. The aim of the present study was to validate the French version of the Desire Thinking Questionnaire (DTQ) and to investigate the relationship between mindfulness, desire thinking and craving among a sample of university students. Four hundred and ninety six university students completed the DTQ and measures of mindfulness, craving and alcohol use. Results from confirmatory factor analyses showed that the two-factor structure proposed in the original DTQ exhibited suitable goodness-of-fit statistics. The DTQ also demonstrated good internal reliability, temporal stability and predictive validity. A set of linear regressions revealed that desire thinking had a confounding effect in the relationship between mindfulness and craving. The confounding role of desire thinking in the relationship between mindfulness and craving suggests that interrupting desire thinking may be a viable clinical option aimed at reducing craving. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. The comet assay as a rapid test in biomonitoring occupational exposure to DNA-damaging agents and effect of confounding factors

    DEFF Research Database (Denmark)

    Møller, P; Knudsen, Lisbeth E.; Loft, S

    2000-01-01

    appeared to have less power than the positive studies. Also, there were poor dose-response relationships in many of the biomonitoring studies. Many factors have been reported to produce effects by the comet assay, e.g., age, air pollution exposure, diet, exercise, gender, infection, residential radon...... be used as criteria for the selection of populations and that data on exercise, diet, and recent infections be registered before blood sampling. Samples from exposed and unexposed populations should be collected at the same time to avoid seasonal variation. In general, the comet assay is considered...... exposure, smoking, and season. Until now, the use of the comet assay has been hampered by the uncertainty of the influence of confounding factors. We argue that none of the confounding factors are unequivocally positive in the majority of the studies. We recommend that age, gender, and smoking status...

  16. Childhood trauma is not a confounder of the overlap between autistic and schizotypal traits: A study in a non-clinical adult sample.

    Science.gov (United States)

    Gong, Jing-Bo; Wang, Ya; Lui, Simon S Y; Cheung, Eric F C; Chan, Raymond C K

    2017-11-01

    Childhood trauma has been shown to be a robust risk factor for mental disorders, and may exacerbate schizotypal traits or contribute to autistic trait severity. However, little is known whether childhood trauma confounds the overlap between schizotypal traits and autistic traits. This study examined whether childhood trauma acts as a confounding variable in the overlap between autistic and schizotypal traits in a large non-clinical adult sample. A total of 2469 participants completed the Autism Spectrum Quotient (AQ), the Schizotypal Personality Questionnaire (SPQ), and the Childhood Trauma Questionnaire-Short Form. Correlation analysis showed that the majority of associations between AQ variables and SPQ variables were significant (p autistic and schizotypal traits could not be explained by shared variance in terms of exposure to childhood trauma. The findings point to important overlaps in the conceptualization of ASD and SSD, independent of childhood trauma. Copyright © 2017 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

    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.

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

    OpenAIRE

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

    2014-01-01

    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 th...

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

    Science.gov (United States)

    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.

  20. The effects of savings on reservation wages and search effort

    NARCIS (Netherlands)

    Lammers, M.

    2014-01-01

    This paper discusses the interrelations among wealth, reservation wages and search effort. A theoretical job search model predicts wealth to affect reservation wages positively, and search effort negatively. Subsequently, reduced form equations for reservation wages and search intensity take these

  1. Effort levels of the partners in networked manufacturing

    Science.gov (United States)

    Chai, G. R.; Cai, Z.; Su, Y. N.; Zong, S. L.; Zhai, G. Y.; Jia, J. H.

    2017-08-01

    Compared with traditional manufacturing mode, could networked manufacturing improve effort levels of the partners? What factors will affect effort level of the partners? How to encourage the partners to improve their effort levels? To answer these questions, we introduce network effect coefficient to build effort level model of the partners in networked manufacturing. The results show that (1) with the increase of the network effect in networked manufacturing, the actual effort level can go beyond the ideal level of traditional manufacturing. (2) Profit allocation based on marginal contribution rate would help improve effort levels of the partners in networked manufacturing. (3) The partners in networked manufacturing who wishes to have a larger distribution ratio must make a higher effort level, and enterprises with insufficient effort should be terminated in networked manufacturing.

  2. Perceived effort for motor control and decision-making.

    Directory of Open Access Journals (Sweden)

    Ignasi Cos

    2017-08-01

    Full Text Available How effort is internally quantified and how it influences both movement generation and decisions between potential movements are 2 difficult questions to answer. Physical costs are known to influence motor control and decision-making, yet we lack a general, principled characterization of how the perception of effort operates across tasks and conditions. Morel and colleagues introduce an insightful approach to that end, assessing effort indifference points and presenting a quadratic law between perceived effort and force production.

  3. Synthetic aperture tissue and flow ultrasound imaging

    DEFF Research Database (Denmark)

    Nikolov, Svetoslav

    imaging applied to medical ultrasound. It is divided into two major parts: tissue and blood flow imaging. Tissue imaging using synthetic aperture algorithms has been investigated for about two decades, but has not been implemented in medical scanners yet. Among the other reasons, the conventional scanning...... and beamformation methods are adequate for the imaging modalities in clinical use - the B-mode imaging of tissue structures, and the color mapping of blood flow. The acquisition time, however, is too long, and these methods fail to perform real-time three-dimensional scans. The synthetic transmit aperture......, on the other hand, can create a Bmode image with as little as 2 emissions, thus significantly speeding-up the scan procedure. The first part of the dissertation describes the synthetic aperture tissue imaging. It starts with an overview of the efforts previously made by other research groups. A classification...

  4. Plant tissue culture techniques

    Directory of Open Access Journals (Sweden)

    Rolf Dieter Illg

    1991-01-01

    Full Text Available Plant cell and tissue culture in a simple fashion refers to techniques which utilize either single plant cells, groups of unorganized cells (callus or organized tissues or organs put in culture, under controlled sterile conditions.

  5. Plant Tissue Culture

    Indian Academy of Sciences (India)

    Admin

    Plant tissue culture is a technique of culturing plant cells, tissues and organs on ... working methods (Box 2) and discovery of the need for B vita- mins and auxins for ... Kotte (Germany) reported some success with growing isolated root tips.

  6. Breast reconstruction - natural tissue

    Science.gov (United States)

    ... flap; TRAM; Latissimus muscle flap with a breast implant; DIEP flap; DIEAP flap; Gluteal free flap; Transverse upper gracilis flap; TUG; Mastectomy - breast reconstruction with natural tissue; Breast cancer - breast reconstruction with natural tissue

  7. FRD tissue archive

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The fishery genetics tissue collection has over 80,000 tissues stored in 95% ethanol representing fishes and invertebrates collected globally but with a focus on the...

  8. Tissue banking in australia.

    Science.gov (United States)

    Ireland, Lynette; McKelvie, Helen

    2003-01-01

    The legal structure for the regulation of tissue banking has existed for many years. In Australia, the donation of human tissue is regulated by legislation in each of the eight States and Territories. These substantially uniform Acts were passed in the late 1970's and early 1980's, based on model legislation and underpinned by the concept of consensual giving. However, it was not until the early 1990's that tissue banking came under the notice of regulatory authorities. Since then the Australian Government has moved quickly to oversee the tissue banking sector in Australia. Banked human tissue has been deemed to be a therapeutic good under the Therapeutic Goods Act 1989, and tissue banks are required to be licensed by the Therapeutic Goods Administration and are audited for compliance with the Code of Good Manufacturing Practice- Human Blood and Tissues. In addition, tissue banks must comply with a myriad of other standards, guidelines and recommendations.

  9. Breast Cancer Tissue Repository

    National Research Council Canada - National Science Library

    Iglehart, J

    1997-01-01

    The Breast Tissue Repository at Duke enters its fourth year of finding. The purpose of the Repository at Duke is to provide substantial quantities of frozen tissue for explorative molecular studies...

  10. Goal Setting and Expectancy Theory Predictions of Effort and Performance.

    Science.gov (United States)

    Dossett, Dennis L.; Luce, Helen E.

    Neither expectancy (VIE) theory nor goal setting alone are effective determinants of individual effort and task performance. To test the combined ability of VIE and goal setting to predict effort and performance, 44 real estate agents and their managers completed questionnaires. Quarterly income goals predicted managers' ratings of agents' effort,…

  11. Development of tissue bank

    Directory of Open Access Journals (Sweden)

    R P Narayan

    2012-01-01

    Full Text Available The history of tissue banking is as old as the use of skin grafting for resurfacing of burn wounds. Beneficial effects of tissue grafts led to wide spread use of auto and allograft for management of varied clinical conditions like skin wounds, bone defects following trauma or tumor ablation. Availability of adequate amount of tissues at the time of requirement was the biggest challenge that forced clinicians to find out techniques to preserve the living tissue for prolonged period of time for later use and thus the foundation of tissue banking was started in early twentieth century. Harvesting, processing, storage and transportation of human tissues for clinical use is the major activity of tissue banks. Low temperature storage of processed tissue is the best preservation technique at present. Tissue banking organization is a very complex system and needs high technical expertise and skilled personnel for proper functioning in a dedicated facility. A small lapse/deviation from the established protocol leads to loss of precious tissues and or harm to recipients as well as the risk of transmission of deadly diseases and tumors. Strict tissue transplant acts and stringent regulations help to streamline the whole process of tissue banking safe for recipients and to community as whole.

  12. Connective Tissue Disorders

    Science.gov (United States)

    ... of connective tissue. Over 200 disorders that impact connective tissue. There are different types: Genetic disorders, such as Ehlers-Danlos syndrome, Marfan syndrome, and osteogenesis imperfecta Autoimmune disorders, such as lupus and scleroderma Cancers, like some types of soft tissue sarcoma Each ...

  13. Musculoskeletal pain and effort-reward imbalance--a systematic review.

    Science.gov (United States)

    Koch, Peter; Schablon, Anja; Latza, Ute; Nienhaus, Albert

    2014-01-15

    Musculoskeletal pain may be triggered by physical strains and psychosocial risk factors. The effort-reward imbalance model (ERI model) is a stress model which measures psychosocial factors in the working world. The question is whether workers with an effort-reward imbalance report musculoskeletal pain more frequently than those with no effort-reward imbalance. A systematic review using a best evidence synthesis approach was conducted to answer this question. A literature search was conducted for the period from 1996 to 2012, using three databases (Pubmed, Embase and PsycINFO). The research criteria related to psychosocial, work-related stress as per the ERI model and to musculoskeletal pain. A quality score was developed using various quality criteria to assess the standard of the studies. The level of evidence was graded as in (Am J Ind Med 39:180-193, 2001). After applying the inclusion criteria, a total of 19 studies were included in the review: 15 cross-sectional studies, three prospective studies and one case-control study. 74% of all studies exhibited good methodological quality, 53% collected data using the original ERI questionnaire, and in 42% of the studies, there was adequate control for physical working conditions. Furthermore, different cut-off points were used to classify exposed and non-exposed individuals. On the basis of 13 studies with a positive, statistically significant association, a moderate level of evidence was inferred for the association between effort-reward imbalance and musculoskeletal pain. The evidence for a role of over-commitment and for its interaction with effort-reward imbalance was rated as inconclusive - on the basis of eight and five studies, respectively. On the basis of the available evidence, no reliable conclusion may be drawn about any association between the psychosocial factors ascertained using the ERI model and musculoskeletal pain. Before a reliable statement can be made on the association between ERI and

  14. Cell and Tissue Engineering

    CERN Document Server

    2012-01-01

    “Cell and Tissue Engineering” introduces the principles and new approaches in cell and tissue engineering. It includes both the fundamentals and the current trends in cell and tissue engineering, in a way useful both to a novice and an expert in the field. The book is composed of 13 chapters all of which are written by the leading experts. It is organized to gradually assemble an insight in cell and tissue function starting form a molecular nano-level, extending to a cellular micro-level and finishing at the tissue macro-level. In specific, biological, physiological, biophysical, biochemical, medical, and engineering aspects are covered from the standpoint of the development of functional substitutes of biological tissues for potential clinical use. Topics in the area of cell engineering include cell membrane biophysics, structure and function of the cytoskeleton, cell-extracellular matrix interactions, and mechanotransduction. In the area of tissue engineering the focus is on the in vitro cultivation of ...

  15. Engineering Complex Tissues

    Science.gov (United States)

    MIKOS, ANTONIOS G.; HERRING, SUSAN W.; OCHAREON, PANNEE; ELISSEEFF, JENNIFER; LU, HELEN H.; KANDEL, RITA; SCHOEN, FREDERICK J.; TONER, MEHMET; MOONEY, DAVID; ATALA, ANTHONY; VAN DYKE, MARK E.; KAPLAN, DAVID; VUNJAK-NOVAKOVIC, GORDANA

    2010-01-01

    This article summarizes the views expressed at the third session of the workshop “Tissue Engineering—The Next Generation,” which was devoted to the engineering of complex tissue structures. Antonios Mikos described the engineering of complex oral and craniofacial tissues as a “guided interplay” between biomaterial scaffolds, growth factors, and local cell populations toward the restoration of the original architecture and function of complex tissues. Susan Herring, reviewing osteogenesis and vasculogenesis, explained that the vascular arrangement precedes and dictates the architecture of the new bone, and proposed that engineering of osseous tissues might benefit from preconstruction of an appropriate vasculature. Jennifer Elisseeff explored the formation of complex tissue structures based on the example of stratified cartilage engineered using stem cells and hydrogels. Helen Lu discussed engineering of tissue interfaces, a problem critical for biological fixation of tendons and ligaments, and the development of a new generation of fixation devices. Rita Kandel discussed the challenges related to the re-creation of the cartilage-bone interface, in the context of tissue engineered joint repair. Frederick Schoen emphasized, in the context of heart valve engineering, the need for including the requirements derived from “adult biology” of tissue remodeling and establishing reliable early predictors of success or failure of tissue engineered implants. Mehmet Toner presented a review of biopreservation techniques and stressed that a new breakthrough in this field may be necessary to meet all the needs of tissue engineering. David Mooney described systems providing temporal and spatial regulation of growth factor availability, which may find utility in virtually all tissue engineering and regeneration applications, including directed in vitro and in vivo vascularization of tissues. Anthony Atala offered a clinician’s perspective for functional tissue

  16. An electromechanical based deformable model for soft tissue simulation.

    Science.gov (United States)

    Zhong, Yongmin; Shirinzadeh, Bijan; Smith, Julian; Gu, Chengfan

    2009-11-01

    Soft tissue deformation is of great importance to surgery simulation. Although a significant amount of research efforts have been dedicated to simulating the behaviours of soft tissues, modelling of soft tissue deformation is still a challenging problem. This paper presents a new deformable model for simulation of soft tissue deformation from the electromechanical viewpoint of soft tissues. Soft tissue deformation is formulated as a reaction-diffusion process coupled with a mechanical load. The mechanical load applied to a soft tissue to cause a deformation is incorporated into the reaction-diffusion system, and consequently distributed among mass points of the soft tissue. Reaction-diffusion of mechanical load and non-rigid mechanics of motion are combined to govern the simulation dynamics of soft tissue deformation. An improved reaction-diffusion model is developed to describe the distribution of the mechanical load in soft tissues. A three-layer artificial cellular neural network is constructed to solve the reaction-diffusion model for real-time simulation of soft tissue deformation. A gradient based method is established to derive internal forces from the distribution of the mechanical load. Integration with a haptic device has also been achieved to simulate soft tissue deformation with haptic feedback. The proposed methodology does not only predict the typical behaviours of living tissues, but it also accepts both local and large-range deformations. It also accommodates isotropic, anisotropic and inhomogeneous deformations by simple modification of diffusion coefficients.

  17. Engineering Musculoskeletal Tissue Interfaces

    Directory of Open Access Journals (Sweden)

    Ece Bayrak

    2018-04-01

    Full Text Available Tissue engineering aims to bring together biomaterials, cells, and signaling molecules within properly designed microenvironments in order to create viable treatment options for the lost or malfunctioning tissues. Design and production of scaffolds and cell-laden grafts that mimic the complex structural and functional features of tissues are among the most important elements of tissue engineering strategy. Although all tissues have their own complex structure, an even more complex case in terms of engineering a proper carrier material is encountered at the tissue interfaces, where two distinct tissues come together. The interfaces in the body can be examined in four categories; cartilage-bone and ligament-bone interfaces at the knee and the spine, tendon-bone interfaces at the shoulder and the feet, and muscle-tendon interface at the skeletal system. These interfaces are seen mainly at the soft-to-hard tissue transitions and they are especially susceptible to injury and tear due to the biomechanical inconsistency between these tissues where high strain fields are present. Therefore, engineering the musculoskeletal tissue interfaces remain a challenge. This review focuses on recent advancements in strategies for musculoskeletal interface engineering using different biomaterial-based platforms and surface modification techniques.

  18. Mesenchymal Stem Cells in Tissue Repair

    Directory of Open Access Journals (Sweden)

    Amy M DiMarino

    2013-09-01

    Full Text Available The advent of mesenchymal stem cell (MSC based therapies for clinical therapeutics has been an exciting and new innovation for the treatment of a variety of diseases associated with inflammation, tissue damage and subsequent regeneration and repair. Application-based ability to measure MSC potency and fate of the cells post-MSC therapy are the variables that confound the use of MSCs therapeutics in human diseases. An evaluation of MSC function and applications with attention to detail in the preparation as well as quality control (QC and quality assurance (QA are only as good as the assays that are developed. In vivo measures of efficacy and potency require an appreciation of the overall pathophysiology of the model and standardization of outcome measures. The new concepts of how MSC’s participate in the tissue regeneration and wound repair process and further, how this is impacted by estimates of efficacy and potency Are important new topics. In this regard,,, this chapter will review some of the in vitro and in vivo assays for MSC function and activity and their application to the clinical arena.

  19. Influence of GSTM1 and GSTT1 genotypes and confounding factors on the frequency of sister chromatid exchange and micronucleus among road construction workers.

    Science.gov (United States)

    Kumar, Anil; Yadav, Anita; Giri, Shiv Kumar; Dev, Kapil; Gautam, Sanjeev Kumar; Gupta, Ranjan; Aggarwal, Neeraj

    2011-07-01

    In the present study, we have investigated the influence of polymorphism of GSTM1 and GSTT1 genes and confounding factors such as age, sex, exposure duration and consumption habits on cytogenetic biomarkers. Frequency of sister chromatid exchanges (SCEs), high frequency cell (HFC) and cytokinesis blocked micronuclei (CBMN) were evaluated in peripheral blood lymphocytes of 115 occupationally exposed road construction workers and 105 unexposed individuals. The distribution of null and positive genotypes of glutathione-S transferase gene was evaluated by multiplex PCR among control and exposed subjects. An increased frequency of CBMN (7.03±2.08); SCE (6.95±1.76) and HFC (6.28±1.69) were found in exposed subjects when compared to referent (CBMN - 3.35±1.10; SCE - 4.13±1.30 and HFC - 3.98±1.56). These results were found statistically significant at p<0.05. When the effect of confounding factors on the frequency of studied biomarkers was evaluated, a strong positive interaction was found. The individuals having GSTM1 and GSTT1 null genotypes had higher frequency of CBMN, SCE and HFC. The association between GSTM1 and GSTT1 genotypes and studied biomarkers was found statistically significant at p<0.05. Our findings suggest that individuals having null type of GST are more susceptible to cytogenetic damage by occupational exposure regardless of confounding factors. There is a significant effect of polymorphism of these genes on cytogenetic biomarkers which are considered as early effects of genotoxic carcinogens. Copyright © 2011 Elsevier Ltd. All rights reserved.

  20. How to ask about patient satisfaction? The visual analogue scale is less vulnerable to confounding factors and ceiling effect than a symmetric Likert scale.

    Science.gov (United States)

    Voutilainen, Ari; Pitkäaho, Taina; Kvist, Tarja; Vehviläinen-Julkunen, Katri

    2016-04-01

    To study the effects of scale type (visual analogue scale vs. Likert), item order (systematic vs. random), item non-response and patient-related characteristics (age, gender, subjective health, need for assistance with filling out the questionnaire and length of stay) on the results of patient satisfaction surveys. Although patient satisfaction is one of the most intensely studied issues in the health sciences, research information about the effects of possible instrument-related confounding factors on patient satisfaction surveys is scant. A quasi-experimental design was employed. A non-randomized sample of 150 surgical patients was gathered to minimize possible alterations in care quality. Data were collected in May-September 2014 from one tertiary hospital in Finland using the Revised Humane Caring Scale instrument. New versions of the instrument were created for the present purposes. In these versions, items were either in a visual analogue format or Likert-scaled, in systematic or random order. The data were analysed using an analysis of covariance and a paired samples t-test. The visual analogue scale items were less vulnerable to bias from confounding factors than were the Likert-scaled items. The visual analogue scale also avoided the ceiling effect better than Likert and the time needed to complete the visual analogue scale questionnaire was 28% shorter than that needed to complete the Likert-scaled questionnaire. The present results supported the use of visual analogue scale rather than Likert scaling in patient satisfaction surveys and stressed the need to account for as many potential confounding factors as possible. © 2015 John Wiley & Sons Ltd.

  1. Excess Mortality in Hyperthyroidism: The Influence of Preexisting Comorbidity and Genetic Confounding: A Danish Nationwide Register-Based Cohort Study of Twins and Singletons

    Science.gov (United States)

    Brandt, Frans; Almind, Dorthe; Christensen, Kaare; Green, Anders; Brix, Thomas Heiberg

    2012-01-01

    Context: Hyperthyroidism is associated with severe comorbidity, such as stroke, and seems to confer increased mortality. However, it is unknown whether this increased mortality is explained by hyperthyroidism per se, comorbidity, and/or genetic confounding. Objective: The objective of the study was to investigate whether hyperthyroidism is associated with an increased mortality and, if so, whether the association is influenced by comorbidity and/or genetic confounding. Methods: This was an observational cohort study using record-linkage data from nationwide Danish health registers. We identified 4850 singletons and 926 twins from same-sex pairs diagnosed with hyperthyroidism. Each case was matched with four controls for age and gender. The Charlson score was calculated from discharge diagnoses on an individual level to measure comorbidity. Cases and controls were followed up for a mean of 10 yr (range 0–31 yr), and the hazard ratio (HR) for mortality was calculated using Cox regression analyses. Results: In singletons there was a significantly higher mortality in individuals diagnosed with hyperthyroidism than in controls [HR 1.37; 95% confidence interval (CI) 1.30–1.46]. This persisted after adjustment for preexisting comorbidity (HR 1,28; 95% CI 1.21–1.36). In twin pairs discordant for hyperthyroidism (625 pairs), the twin with hyperthyroidism had an increased mortality compared with the corresponding cotwin (HR 1.43; 95% CI 1.09–1.88). However, this was found only in dizygotic pairs (HR 1.80; 95% CI 1.27–2.55) but not in monozygotic pairs (HR 0.95; 95% CI 0.60–1.50). Conclusions: Hyperthyroidism is associated with an increased mortality independent of preexisting comorbidity. The study of twin pairs discordant for hyperthyroidism suggests that genetic confounding influences the association between hyperthyroidism and mortality. PMID:22930783

  2. Distance to High-Voltage Power Lines and Risk of Childhood Leukemia – an Analysis of Confounding by and Interaction with Other Potential Risk Factors

    DEFF Research Database (Denmark)

    Pedersen, Camilla; Bräuner, Elvira V; Rod, Naja Hulvej

    2014-01-01

    . 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......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...

  3. Toward a Rational and Mechanistic Account of Mental Effort.

    Science.gov (United States)

    Shenhav, Amitai; Musslick, Sebastian; Lieder, Falk; Kool, Wouter; Griffiths, Thomas L; Cohen, Jonathan D; Botvinick, Matthew M

    2017-07-25

    In spite of its familiar phenomenology, the mechanistic basis for mental effort remains poorly understood. Although most researchers agree that mental effort is aversive and stems from limitations in our capacity to exercise cognitive control, it is unclear what gives rise to those limitations and why they result in an experience of control as costly. The presence of these control costs also raises further questions regarding how best to allocate mental effort to minimize those costs and maximize the attendant benefits. This review explores recent advances in computational modeling and empirical research aimed at addressing these questions at the level of psychological process and neural mechanism, examining both the limitations to mental effort exertion and how we manage those limited cognitive resources. We conclude by identifying remaining challenges for theoretical accounts of mental effort as well as possible applications of the available findings to understanding the causes of and potential solutions for apparent failures to exert the mental effort required of us.

  4. DNA from keratinous tissue

    DEFF Research Database (Denmark)

    Bengtsson, Camilla F.; Olsen, Maja E.; Brandt, Luise Ørsted

    2011-01-01

    Keratinous tissues such as nail, hair, horn, scales and feather have been used as a source of DNA for over 20 years. Particular benefits of such tissues include the ease with which they can be sampled, the relative stability of DNA in such tissues once sampled, and, in the context of ancient...... genetic analyses, the fact that sampling generally causes minimal visual damage to valuable specimens. Even when freshly sampled, however, the DNA quantity and quality in the fully keratinized parts of such tissues is extremely poor in comparison to other tissues such as blood and muscle – although little...... systematic research has been undertaken to characterize how such degradation may relate to sample source. In this review paper we present the current understanding of the quality and limitations of DNA in two key keratinous tissues, nail and hair. The findings indicate that although some fragments of nuclear...

  5. Effort-Based Career Opportunities and Working Time

    OpenAIRE

    Bratti, M.; Staffolani, S.

    2005-01-01

    The authors evaluate the economic effects of the hypothesis of effort-based career opportunities, described as a situation in which a firm creates incentives for employees to work longer hours than bargained (or desired), by making career prospects depend on relative working hours. Firms' personnel management policies may tend to increase working time (or workers' effort) in order to maximize profits. Effort-based career opportunities raise working time, production and output per worker, and ...

  6. The Role of Cognitive Effort in Framing Effects

    OpenAIRE

    Krzysztof Przybyszewski; Dorota Rutkowska

    2013-01-01

    Framing effects are a common bias in people making risky decisions. The account for this bias is found in the loss aversion derived from Prospect Theory. Most often in the decision making literature this is the effortful processes that are claimed to reduce framing effects in risky choice tasks i.e. investing of mental effort should de-bias the decision makers. However, in goal framing studies, effortful mental processes may produce those effects. In our experiment participants were primed wi...

  7. Greater effort increases perceived value in an invertebrate.

    Science.gov (United States)

    Czaczkes, Tomer J; Brandstetter, Birgit; di Stefano, Isabella; Heinze, Jürgen

    2018-05-01

    Expending effort is generally considered to be undesirable. However, both humans and vertebrates will work for a reward they could also get for free. Moreover, cues associated with high-effort rewards are preferred to low-effort associated cues. Many explanations for these counterintuitive findings have been suggested, including cognitive dissonance (self-justification) or a greater contrast in state (e.g., energy or frustration level) before and after an effort-linked reward. Here, we test whether effort expenditure also increases perceived value in ants, using both classical cue-association methods and pheromone deposition, which correlates with perceived value. In 2 separate experimental setups, we show that pheromone deposition is higher toward the reward that requires more effort: 47% more pheromone deposition was performed for rewards reached via a vertical runway (high effort) compared with ones reached via a horizontal runway (low effort), and deposition rates were 28% higher on rough (high effort) versus smooth (low effort) runways. Using traditional cue-association methods, 63% of ants trained on different surface roughness, and 70% of ants trained on different runway elevations, preferred the high-effort related cues on a Y maze. Finally, pheromone deposition to feeders requiring memorization of one path bifurcation was up to 29% higher than to an identical feeder requiring no learning. Our results suggest that effort affects value perception in ants. This effect may stem from a cognitive process, which monitors the change in a generalized hedonic state before and after reward. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  8. Effort--reward imbalance and medically certified absence for mental health problems: a prospective study of white-collar workers.

    Science.gov (United States)

    Ndjaboué, R; Brisson, C; Vézina, M; Blanchette, C; Bourbonnais, R

    2014-01-01

    Little is known about the effects of psychosocial work factors on objectively assessed mental health problems leading to medically certified absence. Only one study has evaluated the prospective effects of effort-reward imbalance (ERI) at work with regards to this outcome. The present study aimed to evaluate the effects of ERI on the incidence of medically certified absence for mental health problems. The study included 2086 white-collar workers (63.3% women) employed in public organisations in Quebec city. Participants were followed over a 9-year period. Medical absences from work were collected from employers' files and psychosocial factors were measured using the ERI questionnaire. Cox regression models were used to estimate the incidence of certified sickness absence due to mental health problems that lasted 5 workdays or more, while controlling for confounders. Workers exposed to ERI had a higher risk of a first spell of medically certified absence for mental health problems (HR=1.38, 95% CI 1.08 to 1.76) compared with unexposed workers. Low reward was significantly associated with a high risk among men (HR=2.80, 95% CI 1.34 to 5.89) but not in women. (HR=1.24, 95% CI 0.90 to 1.73). Effort at work had no effect on certified absence. All these effects were adjusted for potential confounders. ERI and low reward at work were prospectively associated with medically certified absence for mental health problems. These effects seem to differ by gender. Primary prevention that is aimed at reducing these stressors should be considered to help reduce the incidence of such severe mental health problems.

  9. Test anxiety in medical school is unrelated to academic performance but correlates with an effort/reward imbalance.

    Science.gov (United States)

    Hahn, Henry; Kropp, Peter; Kirschstein, Timo; Rücker, Gernot; Müller-Hilke, Brigitte

    2017-01-01

    During their early years at medical school, students repeatedly criticize their workload, time constraints and test associated stress. At the same time, depressiveness and anxiety among first and second year medical students are on the rise. We therefore hypothesized that test anxiety may be related to depressiveness and considered cognitive and academic performances as confounders for the former and psychosocial distress for the latter. A whole class of 200 second year students was invited to participate in the study. Anxiety as a trait, depressiveness, crystallized intelligence, verbal fluency and psychosocial distress were assessed using validated tests and questionnaires. Acute state anxiety and sympathetic stress parameters were measured in real life situations immediately before an oral and a written exam and paired tests were used to compare the individual anxieties at the various time points. Previous academic performances were self-reported, the results of the impending exams were monitored. Finally, correlations were performed to test for interrelatedness between academic performances and the various personal, cognitive and psychosocial factors. Acute test anxiety did not correlate with depressiveness nor did it correlate with previous nor impending academic performances nor any of the expected confounders on academic performance. However both, depressiveness and test anxiety strongly correlated with the perceived imbalance between efforts spent and rewards received. Moreover, anxiety as a trait not only correlated with acute state anxiety before an exam but was also significantly correlated to the feeling of over-commitment. Depressiveness during the early years of medical school seems unrelated to test anxiety and academic performance. Instead, it strongly correlated with the psychosocial distress emanating from attending medical school and points at a perceived imbalance between efforts spent and rewards received.

  10. Tissue engineering in dentistry.

    Science.gov (United States)

    Abou Neel, Ensanya Ali; Chrzanowski, Wojciech; Salih, Vehid M; Kim, Hae-Won; Knowles, Jonathan C

    2014-08-01

    of this review is to inform practitioners with the most updated information on tissue engineering and its potential applications in dentistry. The authors used "PUBMED" to find relevant literature written in English and published from the beginning of tissue engineering until today. A combination of keywords was used as the search terms e.g., "tissue engineering", "approaches", "strategies" "dentistry", "dental stem cells", "dentino-pulp complex", "guided tissue regeneration", "whole tooth", "TMJ", "condyle", "salivary glands", and "oral mucosa". Abstracts and full text articles were used to identify causes of craniofacial tissue loss, different approaches for craniofacial reconstructions, how the tissue engineering emerges, different strategies of tissue engineering, biomaterials employed for this purpose, the major attempts to engineer different dental structures, finally challenges and future of tissue engineering in dentistry. Only those articles that dealt with the tissue engineering in dentistry were selected. There have been a recent surge in guided tissue engineering methods to manage periodontal diseases beyond the traditional approaches. However, the predictable reconstruction of the innate organisation and function of whole teeth as well as their periodontal structures remains challenging. Despite some limited progress and minor successes, there remain distinct and important challenges in the development of reproducible and clinically safe approaches for oral tissue repair and regeneration. Clearly, there is a convincing body of evidence which confirms the need for this type of treatment, and public health data worldwide indicates a more than adequate patient resource. The future of these therapies involving more biological approaches and the use of dental tissue stem cells is promising and advancing. Also there may be a significant interest of their application and wider potential to treat disorders beyond the craniofacial region. Considering the

  11. Biomaterials for Tissue Engineering

    Science.gov (United States)

    Lee, Esther J.; Kasper, F. Kurtis; Mikos, Antonios G.

    2013-01-01

    Biomaterials serve as an integral component of tissue engineering. They are designed to provide architectural framework reminiscent of native extracellular matrix in order to encourage cell growth and eventual tissue regeneration. Bone and cartilage represent two distinct tissues with varying compositional and mechanical properties. Despite these differences, both meet at the osteochondral interface. This article presents an overview of current biomaterials employed in bone and cartilage applications, discusses some design considerations, and alludes to future prospects within this field of research. PMID:23820768

  12. Stretch-sensitive paresis and effort perception in hemiparesis.

    Science.gov (United States)

    Vinti, Maria; Bayle, Nicolas; Hutin, Emilie; Burke, David; Gracies, Jean-Michel

    2015-08-01

    In spastic paresis, stretch applied to the antagonist increases its inappropriate recruitment during agonist command (spastic co-contraction). It is unknown whether antagonist stretch: (1) also affects agonist recruitment; (2) alters effort perception. We quantified voluntary activation of ankle dorsiflexors, effort perception, and plantar flexor co-contraction during graded dorsiflexion efforts at two gastrocnemius lengths. Eighteen healthy (age 41 ± 13) and 18 hemiparetic (age 54 ± 12) subjects performed light, medium and maximal isometric dorsiflexion efforts with the knee flexed or extended. We determined dorsiflexor torque, Root Mean Square EMG and Agonist Recruitment/Co-contraction Indices (ARI/CCI) from the 500 ms peak voluntary agonist recruitment in a 5-s maximal isometric effort in tibialis anterior, soleus and medial gastrocnemius. Subjects retrospectively reported effort perception on a 10-point visual analog scale. During gastrocnemius stretch in hemiparetic subjects, we observed: (1) a 25 ± 7 % reduction of tibialis anterior voluntary activation (maximum reduction 98 %; knee extended vs knee flexed; p = 0.007, ANOVA); (2) an increase in dorsiflexion effort perception (p = 0.03, ANCOVA). Such changes did not occur in healthy subjects. Effort perception depended on tibialis anterior recruitment only (βARI(TA) = 0.61, p hemiparesis, voluntary ability to recruit agonist motoneurones is impaired--sometimes abolished--by antagonist stretch, a phenomenon defined here as stretch-sensitive paresis. In addition, spastic co-contraction increases effort perception, an additional incentive to evaluate and treat this phenomenon.

  13. Sharing Information among Various Organizations in Relief Efforts

    National Research Council Canada - National Science Library

    Costur, Gurkan

    2005-01-01

    .... An analysis is presented of the December 2004 Indian Ocean tsunami relief effort; specifically, how different organizations such as the military, United Nations, and non-governmental organizations...

  14. Stochastic evolutionary dynamics in minimum-effort coordination games

    Science.gov (United States)

    Li, Kun; Cong, Rui; Wang, Long

    2016-08-01

    The minimum-effort coordination game draws recently more attention for the fact that human behavior in this social dilemma is often inconsistent with the predictions of classical game theory. Here, we combine evolutionary game theory and coalescence theory to investigate this game in finite populations. Both analytic results and individual-based simulations show that effort costs play a key role in the evolution of contribution levels, which is in good agreement with those observed experimentally. Besides well-mixed populations, set structured populations have also been taken into consideration. Therein we find that large number of sets and moderate migration rate greatly promote effort levels, especially for high effort costs.

  15. Tissue banking: public awareness in Indonesia

    International Nuclear Information System (INIS)

    Nazly Hilmy

    1999-01-01

    Public awareness and acceptance on the benefit of Tissue Bank (TB) and its products in Indonesia are still very low, however four productive TBs are in operation by using mostly tissues from living donors. Except for medical doctors, nurses and experts who are involved in the establishment of the TB as well as who applied the products, almost nobody else understand what kind of bank this tissue bank is. Ethical in collecting tissues from non- living donors and using of this human tissues for safe medical application has several considerations that should be overcome, such as religious, legal and medical considerations. Legal and medical considerations are not very difficult to be faced. People are reluctant to give up by cutting off the needed tissue of a dead relative to help someone else who is suffering from a life threatening disease. Our duty is to enlighten the public about this bank by means of seminars, exposition, writings and discussions. We can use the electronic mass- media or printed one to explain the necessity of this tissue bank. We also need to involve leaders of religions, government high ranking officials as well as related Government institutions. Otherwise the tissues that are needed can only be obtained from the poor, the homeless whose health condition we do not know and no relatives who can give their permission for the taking of parts of the body. This is a very unethical way. Since January 1998, Batan Research Tissue Bank together with several hospitals in Indonesia have done four seminars, two discussions, two expositions, producing leaflets and carried out training in this matter. But it is not enough. More efforts should be done

  16. Bioactive polymeric scaffolds for tissue engineering

    Directory of Open Access Journals (Sweden)

    Scott Stratton

    2016-12-01

    Full Text Available A variety of engineered scaffolds have been created for tissue engineering using polymers, ceramics and their composites. Biomimicry has been adopted for majority of the three-dimensional (3D scaffold design both in terms of physicochemical properties, as well as bioactivity for superior tissue regeneration. Scaffolds fabricated via salt leaching, particle sintering, hydrogels and lithography have been successful in promoting cell growth in vitro and tissue regeneration in vivo. Scaffold systems derived from decellularization of whole organs or tissues has been popular due to their assured biocompatibility and bioactivity. Traditional scaffold fabrication techniques often failed to create intricate structures with greater resolution, not reproducible and involved multiple steps. The 3D printing technology overcome several limitations of the traditional techniques and made it easier to adopt several thermoplastics and hydrogels to create micro-nanostructured scaffolds and devices for tissue engineering and drug delivery. This review highlights scaffold fabrication methodologies with a focus on optimizing scaffold performance through the matrix pores, bioactivity and degradation rate to enable tissue regeneration. Review highlights few examples of bioactive scaffold mediated nerve, muscle, tendon/ligament and bone regeneration. Regardless of the efforts required for optimization, a shift in 3D scaffold uses from the laboratory into everyday life is expected in the near future as some of the methods discussed in this review become more streamlined.

  17. Articular cartilage: from formation to tissue engineering.

    Science.gov (United States)

    Camarero-Espinosa, Sandra; Rothen-Rutishauser, Barbara; Foster, E Johan; Weder, Christoph

    2016-05-26

    Hyaline cartilage is the nonlinear, inhomogeneous, anisotropic, poro-viscoelastic connective tissue that serves as friction-reducing and load-bearing cushion in synovial joints and is vital for mammalian skeletal movements. Due to its avascular nature, low cell density, low proliferative activity and the tendency of chondrocytes to de-differentiate, cartilage cannot regenerate after injury, wear and tear, or degeneration through common diseases such as osteoarthritis. Therefore severe damage usually requires surgical intervention. Current clinical strategies to generate new tissue include debridement, microfracture, autologous chondrocyte transplantation, and mosaicplasty. While articular cartilage was predicted to be one of the first tissues to be successfully engineered, it proved to be challenging to reproduce the complex architecture and biomechanical properties of the native tissue. Despite significant research efforts, only a limited number of studies have evolved up to the clinical trial stage. This review article summarizes the current state of cartilage tissue engineering in the context of relevant biological aspects, such as the formation and growth of hyaline cartilage, its composition, structure and biomechanical properties. Special attention is given to materials development, scaffold designs, fabrication methods, and template-cell interactions, which are of great importance to the structure and functionality of the engineered tissue.

  18. Target gene expression levels and competition between transfected and endogenous microRNAs are strong confounding factors in microRNA high-throughput experiments

    Science.gov (United States)

    2012-01-01

    Background MicroRNA (miRNA) target genes tend to have relatively long and conserved 3' untranslated regions (UTRs), but to what degree these characteristics contribute to miRNA targeting is poorly understood. Different high-throughput experiments have, for example, shown that miRNAs preferentially regulate genes with both short and long 3' UTRs and that target site conservation is both important and irrelevant for miRNA targeting. Results We have analyzed several gene context-dependent features, including 3' UTR length, 3' UTR conservation, and messenger RNA (mRNA) expression levels, reported to have conflicting influence on miRNA regulation. By taking into account confounding factors such as technology-dependent experimental bias and competition between transfected and endogenous miRNAs, we show that two factors - target gene expression and competition - could explain most of the previously reported experimental differences. Moreover, we find that these and other target site-independent features explain about the same amount of variation in target gene expression as the target site-dependent features included in the TargetScan model. Conclusions Our results show that it is important to consider confounding factors when interpreting miRNA high throughput experiments and urge special caution when using microarray data to compare average regulatory effects between groups of genes that have different average gene expression levels. PMID:22325809

  19. Is social isolation/alienation confounded with, and non-independent of, emotional distress in its association with early onset of coronary artery disease?

    Science.gov (United States)

    Ketterer, Mark; Rose, Benjamin; Knysz, Walter; Farha, Amjad; Deveshwar, Sangita; Schairer, John; Keteyian, Steven J

    2011-03-01

    Both emotional distress (ED) and social isolation/alienation (SI/A) have been found to prospectively predict adverse cardiac events, but few studies have tested the confounding/redundancy of these measures as correlates/predictors of outcomes. In this study, 163 patients with documented coronary artery disease (CAD) were interviewed for multiple indices of SI/A and administered the Symptom Checklist 90 - Revised (SCL90R). A spouse or friend provided an independent rating of ED using the spouse/friend version of the Ketterer Stress Symptom Frequency Checklist (KSSFC). The measures of ED and SI/A covaried. All three scales from the KSSFC (depression, anxiety, and "AIAI" - aggravation, irritation, anger, and impatience), and three scales from the SCL90R (anxiety, depression, and psychoticism), were associated with early Age at Initial Diagnosis (AAID) of CAD. Neither three scales derived from the SCL90R (shyness, feeling abused, and feeling lonely) nor the interview indices of SI/A (married, living alone, having a confidant, self description as a lone wolf, and self-description as lonely) were associated with early AAID. Thus, it is concluded that the present results indicate that ED and SI/A are confounded and that, even when tested head-to-head in a multivariate analysis, only ED is associated with AAID.

  20. Abnormal mineral metabolism and mortality in hemodialysis patients with secondary hyperparathyroidism: evidence from marginal structural models used to adjust for time-dependent confounding.

    Science.gov (United States)

    Fukagawa, Masafumi; Kido, Ryo; Komaba, Hirotaka; Onishi, Yoshihiro; Yamaguchi, Takuhiro; Hasegawa, Takeshi; Kurita, Noriaki; Fukuma, Shingo; Akizawa, Tadao; Fukuhara, Shunichi

    2014-06-01

    Hemodialysis patients with mineral and bone disorders (MBDs) have an abnormally high relative risk of death, but their absolute risk of death is unknown. Further, previous studies have not accounted for possible time-dependent confounding of the association between MBD markers and death due to the effect of markers of MBD on treatments, which subsequently may affect MBD markers. Multicenter, 3-year, prospective, case-cohort study. 8,229 hemodialysis patients with secondary hyperparathyroidism (parathyroid hormone level ≥180 pg/mL and/or receiving vitamin D receptor activators) at 86 facilities in Japan. Serum phosphorus, calcium, and parathyroid hormone levels. All-cause mortality. Marginal structural models were used to compute absolute differences in all-cause mortality associated with different levels of predictors while accounting for time-dependent confounding. The association between phosphorus level and mortality appeared U-shaped, although only higher phosphorus level categories reached statistical significance: compared to those with phosphorus levels of 5.0-5.9 mg/dL (1.61-1.93 mmol/L), patients with the highest (≥9.0 mg/dL [≥2.90 mmol/L]) phosphorus levels had 9.4 excess deaths/100 person-years (rate ratio, 2.79 [95% CI, 1.26-6.15]), whereas no association was found for the lowest phosphorus category (secondary hyperparathyroidism. Copyright © 2014 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

  1. "I put in effort, therefore I am passionate": Investigating the path from effort to passion in entrepreneurship

    OpenAIRE

    Gielnik, Michael Marcus; Spitzmuller, Matthias; Schmitt, Antje; Klemann, Katharina; Frese, Michael

    2015-01-01

    Most theoretical frameworks in entrepreneurship emphasize that entrepreneurial passion drives entrepreneurial effort. We hypothesize that the reverse effect is also true, and investigate changes in passion as an outcome of effort. Based on theories of self-regulation and self-perception, we hypothesize that making new venture progress and free choice are two factors that help to explain why and under which conditions entrepreneurial effort affects entrepreneurial passion. We undertook two stu...

  2. In-effort perfusion pulmonary tomo-scintigraphies for pre-surgery evaluation of severe emphysema

    International Nuclear Information System (INIS)

    Poiseau, E.; Roue, C.; Bonnin, F.; Stievenart, J.L.; Fournier, M.; Bok, B.

    1997-01-01

    The pulmonary reduction surgery improves the in-effort tolerance of certain severe emphysema, possibly by the compression of zones of adjacent healthy pulmonary parenchyma. Six patients afflicted with severe emphysema (5 M and 1 F, 20 to 63 years old) benefited at each 3 days by an at-rest and in-effort perfusion pulmonary tomo-scintigraphy (PPTS), after a trial interval of 6 minutes. After injection IV of 6 mCi of MAA- 99m Tc, in sitting position, 120 projection images were acquired with a single-head camera on a 128 x 128 matrix, with a high resolution collimator. After reconstruction with a Metz filter, without corrections of attenuations, the coronal and cross sections were recorded on films in a standard procedure. These were visually interpreted by two independent senior physicians. The procedure has been tolerated by all the patients. Differences of pulmonary perfusion occurred at rest in comparison with the in-effort condition in 4 patients. In all the cases concerned were the zones of pulmonary parenchyma appearing as strongly injured in tomodensitometry. The in-effort pulmonary perfusion improves in 3 patients and impairs in one patient. The role of bubble and implied pulmonary diseases in the deterioration of pulmonary function, respectively, is difficult to estimate. The improvement of in-effort pulmonary perfusion could suggest the persistence of functional pulmonary tissue. On the other side, its deterioration could express the compressive character of bubbles and thus could be an indicator of severity. The observation during this pilot study of the differences between at-rest and in-effort pulmonary perfusion urges utilisation of a tool of analysis of image superposition (PPTS and scans) to study in a group of patients the correlations between the perfusion variations and the post-surgery development, in order to know better the pathophysiology of diseases and select better the patients

  3. Damage Models for Soft Tissues: A Survey.

    Science.gov (United States)

    Li, Wenguang

    Damage to soft tissues in the human body has been investigated for applications in healthcare, sports, and biomedical engineering. This paper reviews and classifies damage models for soft tissues to summarize achievements, identify new directions, and facilitate finite element analysis. The main ideas of damage modeling methods are illustrated and interpreted. A few key issues related to damage models, such as experimental data curve-fitting, computational effort, connection between damage and fractures/cracks, damage model applications, and fracture/crack extension simulation, are discussed. Several new challenges in the field are identified and outlined. This review can be useful for developing more advanced damage models and extending damage modeling methods to a variety of soft tissues.

  4. Controlled drug release for tissue engineering.

    Science.gov (United States)

    Rambhia, Kunal J; Ma, Peter X

    2015-12-10

    Tissue engineering is often referred to as a three-pronged discipline, with each prong corresponding to 1) a 3D material matrix (scaffold), 2) drugs that act on molecular signaling, and 3) regenerative living cells. Herein we focus on reviewing advances in controlled release of drugs from tissue engineering platforms. This review addresses advances in hydrogels and porous scaffolds that are synthesized from natural materials and synthetic polymers for the purposes of controlled release in tissue engineering. We pay special attention to efforts to reduce the burst release effect and to provide sustained and long-term release. Finally, novel approaches to controlled release are described, including devices that allow for pulsatile and sequential delivery. In addition to recent advances, limitations of current approaches and areas of further research are discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Best-effort Support for a Virtual Seminar Room

    DEFF Research Database (Denmark)

    Sharp, Robin; Todirica, Edward Alexandru

    2002-01-01

    This paper describes the RTMM Virtual Seminar Room, an interactive distributed multimedia application based on a platform with a simple middleware architecture, using best effort scheduling and a best effort network service. Emphasis has been placed on achieving low latency in all parts...

  6. Development Efforts Of Oil Companies As Perceived By Rural ...

    African Journals Online (AJOL)

    ... that the host communities are highly satisfied with companies' efforts (projects and services) to them. Based on these findings, recommendations were made. Key words: Oil producing communities; oil exploration/production; company's development efforts; Journal of Agriculture and Social Research Vol.4(1) 2004: 60-71 ...

  7. Heuristics Made Easy: An Effort-Reduction Framework

    Science.gov (United States)

    Shah, Anuj K.; Oppenheimer, Daniel M.

    2008-01-01

    In this article, the authors propose a new framework for understanding and studying heuristics. The authors posit that heuristics primarily serve the purpose of reducing the effort associated with a task. As such, the authors propose that heuristics can be classified according to a small set of effort-reduction principles. The authors use this…

  8. 15 CFR 930.114 - Secretarial mediation efforts.

    Science.gov (United States)

    2010-01-01

    ... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false Secretarial mediation efforts. 930.114... MANAGEMENT FEDERAL CONSISTENCY WITH APPROVED COASTAL MANAGEMENT PROGRAMS Secretarial Mediation § 930.114 Secretarial mediation efforts. (a) Following the close of the hearing, the hearing officer shall transmit the...

  9. Seasonal abundance, distribution, and catch per unit effort using gill ...

    African Journals Online (AJOL)

    Catch per unit effort was obtained for the fish of the Sundays .... Methods. Catch per unit effort (numbers and weight/net) of fish in the estuary was obtained from 55 .... Table 1 CPUE (number and mass) of fish caught monthly using gill-net over 12·h periods with 55 nettings at .... The abundance of some other species may.

  10. Quantifying commercial catch and effort of monkfish Lophius ...

    African Journals Online (AJOL)

    Catch-per-unit-effort (cpue) data of vessels targeting monkfish and sole (the two ... analysed using two different methods to construct indices of abundance. ... in Namibia to all tail-weight classes is not appropriate for the current fishery and needs ... Keywords: catch per unit effort, Generalized Linear Model, Lophius vaillanti, ...

  11. Determinants of Tourists Information Search Effort: The Case of ...

    African Journals Online (AJOL)

    The paper examines tourist information search effort prior to the visit to a selected destination. The focus was on identifying the key variables that influence the information search effort of Ghana's international visitors from the United States of America, the United Kingdom and Germany. The Dummy Multiple Regression ...

  12. Policies and Programmatic Efforts Pertaining to Fatherhood: Commentary

    Science.gov (United States)

    Raikes, Helen; Bellotti, Jeanne

    2007-01-01

    The articles in this section focus attention on (1) the historical shift in policies that affect the young men of this nation (2) how fatherhood policies and programmatic efforts are expanding and (3) how fatherhood practices and policies could and perhaps should be expanded and elaborated further. These efforts are linked to a growing body of…

  13. Money Laundering and International Efforts to Fight It

    OpenAIRE

    David Scott

    1996-01-01

    According to one estimate, US$300 billion to US$500 billion in proceeds from serious crime is laundered each year. Left unchecked, money laundering could criminalize the financial system and undermine development efforts in emerging markets. The author reviews efforts by international bodies to fight it.

  14. Polio eradication efforts in regions of geopolitical strife: the Boko ...

    African Journals Online (AJOL)

    Polio eradication efforts in regions of geopolitical strife: the Boko Haram threat to efforts in sub-Saharan Africa. ... Targets of Boko Haram aggression in these zones include violence against polio workers, disruption of polio immunization campaigns, with consequent reduced access to health care and immunization.

  15. Effort reward imbalance, and salivary cortisol in the morning

    DEFF Research Database (Denmark)

    Eller, Nanna Hurwitz; Nielsen, Søren Feodor; Blønd, Morten

    2012-01-01

    Effort reward imbalance (ERI) is suggested to increase risk for stress and is hypothesized to increase cortisol levels, especially the awakening cortisol response, ACR.......Effort reward imbalance (ERI) is suggested to increase risk for stress and is hypothesized to increase cortisol levels, especially the awakening cortisol response, ACR....

  16. Private Speech Moderates the Effects of Effortful Control on Emotionality

    Science.gov (United States)

    Day, Kimberly L.; Smith, Cynthia L.; Neal, Amy; Dunsmore, Julie C.

    2018-01-01

    Research Findings: In addition to being a regulatory strategy, children's private speech may enhance or interfere with their effortful control used to regulate emotion. The goal of the current study was to investigate whether children's private speech during a selective attention task moderated the relations of their effortful control to their…

  17. Functional Attachment of Soft Tissues to Bone: Development, Healing, and Tissue Engineering

    Science.gov (United States)

    Lu, Helen H.; Thomopoulos, Stavros

    2014-01-01

    Connective tissues such as tendons or ligaments attach to bone across a multitissue interface with spatial gradients in composition, structure, and mechanical properties. These gradients minimize stress concentrations and mediate load transfer between the soft and hard tissues. Given the high incidence of tendon and ligament injuries and the lack of integrative solutions for their repair, interface regeneration remains a significant clinical challenge. This review begins with a description of the developmental processes and the resultant structure-function relationships that translate into the functional grading necessary for stress transfer between soft tissue and bone. It then discusses the interface healing response, with a focus on the influence of mechanical loading and the role of cell-cell interactions. The review continues with a description of current efforts in interface tissue engineering, highlighting key strategies for the regeneration of the soft tissue–to-bone interface, and concludes with a summary of challenges and future directions. PMID:23642244

  18. Can tissues be owned?

    African Journals Online (AJOL)

    2013-06-17

    Jun 17, 2013 ... Regulations Regarding Rendering of Clinical Forensic Medicine ... 1 Special Interest Research Group on Biotechnology and Medical Law of the College of Law, University of ... persons for the following medical and dental purposes: ... tissue to the international market were taking tissue without consent.

  19. Neural tissue-spheres

    DEFF Research Database (Denmark)

    Andersen, Rikke K; Johansen, Mathias; Blaabjerg, Morten

    2007-01-01

    By combining new and established protocols we have developed a procedure for isolation and propagation of neural precursor cells from the forebrain subventricular zone (SVZ) of newborn rats. Small tissue blocks of the SVZ were dissected and propagated en bloc as free-floating neural tissue...... content, thus allowing experimental studies of neural precursor cells and their niche...

  20. Men's Work Efforts and the Transition to Fatherhood.

    Science.gov (United States)

    Astone, Nan Marie; Dariotis, Jacinda; Sonenstein, Freya; Pleck, Joseph H; Hynes, Kathryn

    2010-03-01

    In this paper we tested three hypotheses: (a) the transition to fatherhood is associated with an increase in work effort; (b) the positive association (if any) between the transition to fatherhood and work effort is greater for fathers who are married at the time of the transition; and (c) the association (if any) is greater for men who make the transition at younger ages. The data are from the National Longitudinal Survey of Youth 1979 Cohort. The transition to fatherhood was associated with an increase in work effort among young unmarried men, but not for married men. Among married men who were on-time fathers, work effort decreased. Among childless men, the marriage transition was associated with increased work effort.

  1. Perception of effort in Exercise Science: Definition, measurement and perspectives.

    Science.gov (United States)

    Pageaux, Benjamin

    2016-11-01

    Perception of effort, also known as perceived exertion or sense of effort, can be described as a cognitive feeling of work associated with voluntary actions. The aim of the present review is to provide an overview of what is perception of effort in Exercise Science. Due to the addition of sensations other than effort in its definition, the neurophysiology of perceived exertion remains poorly understood. As humans have the ability to dissociate effort from other sensations related to physical exercise, the need to use a narrower definition is emphasised. Consequently, a definition and some brief guidelines for its measurement are provided. Finally, an overview of the models present in the literature aiming to explain its neurophysiology, and some perspectives for future research are offered.

  2. HIV Persistence in Adipose Tissue Reservoirs.

    Science.gov (United States)

    Couturier, Jacob; Lewis, Dorothy E

    2018-02-01

    The purpose of this review is to examine the evidence describing adipose tissue as a reservoir for HIV-1 and how this often expansive anatomic compartment contributes to HIV persistence. Memory CD4 T cells and macrophages, the major host cells for HIV, accumulate in adipose tissue during HIV/SIV infection of humans and rhesus macaques. Whereas HIV and SIV proviral DNA is detectable in CD4 T cells of multiple fat depots in virtually all infected humans and monkeys examined, viral RNA is less frequently detected, and infected macrophages may be less prevalent in adipose tissue. However, based on viral outgrowth assays, adipose-resident CD4 T cells are latently infected with virus that is replication-competent and infectious. Additionally, adipocytes interact with CD4 T cells and macrophages to promote immune cell activation and inflammation which may be supportive for HIV persistence. Antiviral effector cells, such as CD8 T cells and NK/NKT cells, are abundant in adipose tissue during HIV/SIV infection and typically exceed CD4 T cells, whereas B cells are largely absent from adipose tissue of humans and monkeys. Additionally, CD8 T cells in adipose tissue of HIV patients are activated and have a late differentiated phenotype, with unique TCR clonotypes of less diversity relative to blood CD8 T cells. With respect to the distribution of antiretroviral drugs in adipose tissue, data is limited, but there may be class-specific penetration of fat depots. The trafficking of infected immune cells within adipose tissues is a common event during HIV/SIV infection of humans and monkeys, but the virus may be mostly transcriptionally dormant. Viral replication may occur less in adipose tissue compared to other major reservoirs, such as lymphoid tissue, but replication competence and infectiousness of adipose latent virus are comparable to other tissues. Due to the ubiquitous nature of adipose tissue, inflammatory interactions among adipocytes and CD4 T cells and macrophages, and

  3. Goal striving strategies and effort mobilization: When implementation intentions reduce effort-related cardiac activity during task performance.

    Science.gov (United States)

    Freydefont, Laure; Gollwitzer, Peter M; Oettingen, Gabriele

    2016-09-01

    Two experiments investigate the influence of goal and implementation intentions on effort mobilization during task performance. Although numerous studies have demonstrated the beneficial effects of setting goals and making plans on performance, the effects of goals and plans on effort-related cardiac activity and especially the cardiac preejection period (PEP) during goal striving have not yet been addressed. According to the Motivational Intensity Theory, participants should increase effort mobilization proportionally to task difficulty as long as success is possible and justified. Forming goals and making plans should allow for reduced effort mobilization when participants perform an easy task. However, when the task is difficult, goals and plans should differ in their effect on effort mobilization. Participants who set goals should disengage, whereas participants who made if-then plans should stay in the field showing high effort mobilization during task performance. As expected, using an easy task in Experiment 1, we observed a lower cardiac PEP in both the implementation intention and the goal intention condition than in the control condition. In Experiment 2, we varied task difficulty and demonstrated that while participants with a mere goal intention disengaged from difficult tasks, participants with an implementation intention increased effort mobilization proportionally with task difficulty. These findings demonstrate the influence of goal striving strategies (i.e., mere goals vs. if-then plans) on effort mobilization during task performance. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Estimation of total Effort and Effort Elapsed in Each Step of Software Development Using Optimal Bayesian Belief Network

    Directory of Open Access Journals (Sweden)

    Fatemeh Zare Baghiabad

    2017-09-01

    Full Text Available Accuracy in estimating the needed effort for software development caused software effort estimation to be a challenging issue. Beside estimation of total effort, determining the effort elapsed in each software development step is very important because any mistakes in enterprise resource planning can lead to project failure. In this paper, a Bayesian belief network was proposed based on effective components and software development process. In this model, the feedback loops are considered between development steps provided that the return rates are different for each project. Different return rates help us determine the percentages of the elapsed effort in each software development step, distinctively. Moreover, the error measurement resulted from optimized effort estimation and the optimal coefficients to modify the model are sought. The results of the comparison between the proposed model and other models showed that the model has the capability to highly accurately estimate the total effort (with the marginal error of about 0.114 and to estimate the effort elapsed in each software development step.

  5. Mildly elevated serum total bilirubin is negatively associated with hemoglobin A1c independently of confounding factors among community-dwelling middle-aged and elderly persons

    Directory of Open Access Journals (Sweden)

    Ryuichi Kawamoto

    2017-08-01

    Full Text Available Abnormally high glycated hemoglobin (Hb (HbA1c is significantly associated with oxidative stress and an increased risk of cardiovascular disease (CVD. Serum total bilirubin (T-B may have a beneficial role in preventing oxidative changes and be a negative risk factor of CVD. Limited information is available on whether serum T-B is an independent confounding factor of HbA1c. The study subjects were 633 men aged 70 ± 9 (mean ± standard deviation (SD years and 878 women aged 70 ± 8 years who were enrolled consecutively from among patients aged ≥40 years through a community-based annual check-up process. We evaluated the relationship between various confounding factors including serum T-B and HbA1c in each gender. Multiple linear regression analysis pertaining to HbA1c showed that in men, serum T-B ( β = −0.139 as well as waist circumference ( β = 0.099, exercise habit ( β = 0.137, systolic blood pressure (SBP ( β = 0.076, triglycerides ( β = 0.087, and uric acid ( β = −0.123 were significantly and independently associated with HbA1c, and in women, serum T-B ( β = −0.084 as well as body mass index ( β = 0.090, smoking status ( β = −0.077, SBP ( β = 0.117, diastolic blood pressure (DBP ( β = −0.155, low-density lipoprotein cholesterol ( β = 0.074, prevalence of antidyslipidemic medication ( β = 0.174, and uric acid ( β = 0.090 were also significantly and independently associated with HbA1c. Multivariate-adjusted serum HbA1c levels were significantly high in subjects with the lowest serum T-B levels in both genders. Serum T-B is an independent confounding factor for HbA1c among community-dwelling middle-aged and elderly persons.

  6. Trust and Reciprocity: Are Effort and Money Equivalent?

    Science.gov (United States)

    Vilares, Iris; Dam, Gregory; Kording, Konrad

    2011-01-01

    Trust and reciprocity facilitate cooperation and are relevant to virtually all human interactions. They are typically studied using trust games: one subject gives (entrusts) money to another subject, which may return some of the proceeds (reciprocate). Currently, however, it is unclear whether trust and reciprocity in monetary transactions are similar in other settings, such as physical effort. Trust and reciprocity of physical effort are important as many everyday decisions imply an exchange of physical effort, and such exchange is central to labor relations. Here we studied a trust game based on physical effort and compared the results with those of a computationally equivalent monetary trust game. We found no significant difference between effort and money conditions in both the amount trusted and the quantity reciprocated. Moreover, there is a high positive correlation in subjects' behavior across conditions. This suggests that trust and reciprocity may be character traits: subjects that are trustful/trustworthy in monetary settings behave similarly during exchanges of physical effort. Our results validate the use of trust games to study exchanges in physical effort and to characterize inter-subject differences in trust and reciprocity, and also suggest a new behavioral paradigm to study these differences. PMID:21364931

  7. Dissociating variability and effort as determinants of coordination.

    Directory of Open Access Journals (Sweden)

    Ian O'Sullivan

    2009-04-01

    Full Text Available When coordinating movements, the nervous system often has to decide how to distribute work across a number of redundant effectors. Here, we show that humans solve this problem by trying to minimize both the variability of motor output and the effort involved. In previous studies that investigated the temporal shape of movements, these two selective pressures, despite having very different theoretical implications, could not be distinguished; because noise in the motor system increases with the motor commands, minimization of effort or variability leads to very similar predictions. When multiple effectors with different noise and effort characteristics have to be combined, however, these two cost terms can be dissociated. Here, we measure the importance of variability and effort in coordination by studying how humans share force production between two fingers. To capture variability, we identified the coefficient of variation of the index and little fingers. For effort, we used the sum of squared forces and the sum of squared forces normalized by the maximum strength of each effector. These terms were then used to predict the optimal force distribution for a task in which participants had to produce a target total force of 4-16 N, by pressing onto two isometric transducers using different combinations of fingers. By comparing the predicted distribution across fingers to the actual distribution chosen by participants, we were able to estimate the relative importance of variability and effort of 1:7, with the unnormalized effort being most important. Our results indicate that the nervous system uses multi-effector redundancy to minimize both the variability of the produced output and effort, although effort costs clearly outweighed variability costs.

  8. Dopamine does double duty in motivating cognitive effort

    Science.gov (United States)

    Westbrook, Andrew; Braver, Todd S.

    2015-01-01

    Cognitive control is subjectively costly, suggesting that engagement is modulated in relationship to incentive state. Dopamine appears to play key roles. In particular, dopamine may mediate cognitive effort by two broad classes of functions: 1) modulating the functional parameters of working memory circuits subserving effortful cognition, and 2) mediating value-learning and decision-making about effortful cognitive action. Here we tie together these two lines of research, proposing how dopamine serves “double duty”, translating incentive information into cognitive motivation. PMID:26889810

  9. Non-Immunogenic Structurally and Biologically Intact Tissue Matrix Grafts for the Immediate Repair of Ballistic-Induced Vascular and Nerve Tissue Injury in Combat Casualty Care

    National Research Council Canada - National Science Library

    Bachrach, Nathaniel

    2003-01-01

    .... This past year the source of he defects was determined to be the freeze-drying process. Ongoing efforts toward process optimization and design modifications that will provide undamaged tissue grafts are presented in this report...

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

    Science.gov (United States)

    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. PsycINFO Database Record (c) 2014 APA, all rights reserved.

  11. Accounting for Time-Varying Confounding in the Relationship Between Obesity and Coronary Heart Disease: Analysis With G-Estimation: The ARIC Study.

    Science.gov (United States)

    Shakiba, Maryam; Mansournia, Mohammad Ali; Salari, Arsalan; Soori, Hamid; Mansournia, Nasrin; Kaufman, Jay S

    2018-06-01

    In longitudinal studies, standard analysis may yield biased estimates of exposure effect in the presence of time-varying confounders that are also intermediate variables. We aimed to quantify the relationship between obesity and coronary heart disease (CHD) by appropriately adjusting for time-varying confounders. This study was performed in a subset of participants from the Atherosclerosis Risk in Communities (ARIC) Study (1987-2010), a US study designed to investigate risk factors for atherosclerosis. General obesity was defined as body mass index (weight (kg)/height (m)2) ≥30, and abdominal obesity (AOB) was defined according to either waist circumference (≥102 cm in men and ≥88 cm in women) or waist:hip ratio (≥0.9 in men and ≥0.85 in women). The association of obesity with CHD was estimated by G-estimation and compared with results from accelerated failure-time models using 3 specifications. The first model, which adjusted for baseline covariates, excluding metabolic mediators of obesity, showed increased risk of CHD for all obesity measures. Further adjustment for metabolic mediators in the second model and time-varying variables in the third model produced negligible changes in the hazard ratios. The hazard ratios estimated by G-estimation were 1.15 (95% confidence interval (CI): 0.83, 1.47) for general obesity, 1.65 (95% CI: 1.35, 1.92) for AOB based on waist circumference, and 1.38 (95% CI: 1.13, 1.99) for AOB based on waist:hip ratio, suggesting that AOB increased the risk of CHD. The G-estimated hazard ratios for both measures were further from the null than those derived from standard models.

  12. Sesgos de confusión por indicación y gravedad en estudios observacionales Confounding bias due to indication and severity in observational studies

    Directory of Open Access Journals (Sweden)

    Javier Nuevo

    2011-04-01

    Full Text Available Los estudios observacionales están sujetos a sesgos que pueden conducir a una interpretación errónea de los resultados. El presente estudio tuvo como objetivo determinar la influencia del tratamiento con omeprazol sobre la duración de la baja laboral en pacientes con esguince de tobillo que tomaban antiinflamatorios no esteroideos. Se utilizaron los registros de la base de datos de la mutua Ibermutuamur. En contra de lo esperado, se observó que los pacientes que recibieron omeprazol presentaron una baja más prolongada que los que no recibieron omeprazol. Es probable que estos hallazgos se deban a la influencia de un sesgo de confusión por gravedad, pues los pacientes que recibieron omeprazol presentaban un esguince más grave, aunque no se puede descartar un sesgo de confusión por indicación. Para evitar la influencia de estos errores sistemáticos se deben controlar los sesgos a lo largo de todo el estudio, desde el diseño hasta el análisis de los datos.Observational studies are subject to biases that may lead to misinterpretation of the results. This study aimed to determine the influence of omeprazole treatment on the duration of sick leave in patients with ankle sprains treated with non-steroidal anti-inflammatory drugs. We used the Ibermutuamur database. Contrary to our expectations, sick leave was longer in patients who received omeprazole than in those who did not. These findings were probably due to the influence of a bias due to confounding by severity, given that patients who received omeprazole had a worse kind of ankle sprain; however, a bias due to confounding by indication cannot be excluded. To avoid the influence of these systematic errors, biases should be monitored from the design stage to the data analysis stage.

  13. Lumbar disc degeneration was not related to spine and hip bone mineral densities in Chinese: facet joint osteoarthritis may confound the association.

    Science.gov (United States)

    Pan, Jianjiang; Lu, Xuan; Yang, Ge; Han, Yongmei; Tong, Xiang; Wang, Yue

    2017-12-01

    A sample of 512 Chinese was studied and we observed that greater disc degeneration on MRI was associated with greater spine DXA BMD. Yet, this association may be confounded by facet joint osteoarthritis. BMD may not be a risk factor for lumbar disc degeneration in Chinese. Evidence suggested that lumbar vertebral bone and intervertebral disc interact with each other in multiple ways. The current paper aims to determine the association between bone mineral density (BMD) and lumbar disc degeneration using a sample of Chinese. We studied 165 patients with back disorders and 347 general subjects from China. All subjects had lumbar spine magnetic resonance (MR) imaging and dual- energy X-ray absorptiometry (DXA) spine BMD studies, and a subset of general subjects had additional hip BMD measurements. On T2-weighted MR images, Pfirrmann score was used to evaluate the degree of lumbar disc degeneration and facet joint osteoarthritis was assessed as none, slight-moderate, and severe. Regression analyses were used to examine the associations between lumbar and hip BMD and disc degeneration, adjusting for age, gender, body mass index (BMI), lumbar region, and facet joint osteoarthritis. Greater facet joint osteoarthritis was associated with greater spine BMD (P osteoarthritis entered the regression model, however, greater spine BMD was associated with greater facet joint osteoarthritis (P  0.05). No statistical association was observed between spine BMD and lumbar disc degeneration in patients with back disorders (P > 0.05), and between hip BMD and disc degeneration in general subjects (P > 0.05). BMD may not be a risk factor for lumbar disc degeneration in Chinese. Facet joint osteoarthritis inflates DXA spine BMD measurements and therefore, may confound the association between spine BMD and disc degeneration.

  14. Smokers' increased risk for disability pension: social confounding or health-mediated effects? Gender-specific analyses of the Hordaland Health Study cohort.

    Science.gov (United States)

    Haukenes, Inger; Riise, Trond; Haug, Kjell; Farbu, Erlend; Maeland, John Gunnar

    2013-09-01

    Studies indicate that cigarette smokers have an increased risk for disability pension, presumably mediated by adverse health effects. However, smoking is also related to socioeconomic status. The current study examined the association between smoking and subsequent disability pension, and whether the association is explained by social confounding and/or health-related mediation. A subsample of 7934 men and 8488 women, aged 40-46, from the Hordaland Health Study, Norway (1997-1999), provided baseline information on smoking status, self-reported health measures and socioeconomic status. Outcome was register-based disability pension from 12 months after baseline to end of 2004. Gender stratified Cox regression analyses were used adjusted for socioeconomic status, physical activity, self-reported health and musculoskeletal pain sites. A total of 155 (2%) men and 333 (3.9%) women were granted disability pension during follow-up. The unadjusted disability risk associated with heavy smoking versus non-smoking was 1.88 (95% CI 1.23 to 2.89) among men and 3.06 (95% CI 2.23 to 4.20) among women. In multivariate analyses, adjusting for socioeconomic status, HRs were 1.33 (95% CI 0.84 to 2.11) among men and 2.22 (95% CI 1.58 to 3.13) among women. Final adjustment for physical activity, self-reported health and musculoskeletal pain further reduced the effect of heavy smoking in women (HR=1.53, 95% CI 1.09 to 2.16). Socioeconomic status confounded the smoking-related risk for disability pension; for female heavy smokers, however, a significant increased risk persisted after adjustment. Women may be particularly vulnerable to heavy smoking and to its sociomedical consequences, such as disability pension.

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

    Science.gov (United States)

    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

  16. Quantification of the impact of a confounding variable on functional connectivity confirms anti-correlated networks in the resting-state.

    Science.gov (United States)

    Carbonell, F; Bellec, P; Shmuel, A

    2014-02-01

    The effect of regressing out the global average signal (GAS) in resting state fMRI data has become a concern for interpreting functional connectivity analyses. It is not clear whether the reported anti-correlations between the Default Mode and the Dorsal Attention Networks are intrinsic to the brain, or are artificially created by regressing out the GAS. Here we introduce a concept, Impact of the Global Average on Functional Connectivity (IGAFC), for quantifying the sensitivity of seed-based correlation analyses to the regression of the GAS. This voxel-wise IGAFC index is defined as the product of two correlation coefficients: the correlation between the GAS and the fMRI time course of a voxel, times the correlation between the GAS and the seed time course. This definition enables the calculation of a threshold at which the impact of regressing-out the GAS would be large enough to introduce spurious negative correlations. It also yields a post-hoc impact correction procedure via thresholding, which eliminates spurious correlations introduced by regressing out the GAS. In addition, we introduce an Artificial Negative Correlation Index (ANCI), defined as the absolute difference between the IGAFC index and the impact threshold. The ANCI allows a graded confidence scale for ranking voxels according to their likelihood of showing artificial correlations. By applying this method, we observed regions in the Default Mode and Dorsal Attention Networks that were anti-correlated. These findings confirm that the previously reported negative correlations between the Dorsal Attention and Default Mode Networks are intrinsic to the brain and not the result of statistical manipulations. Our proposed quantification of the impact that a confound may have on functional connectivity can be generalized to global effect estimators other than the GAS. It can be readily applied to other confounds, such as systemic physiological or head movement interferences, in order to quantify their

  17. 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).

    Science.gov (United States)

    Verner, Marc-André; 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

    2015-12-01

    Prenatal exposure to perfluoroalkyl substances (PFAS) has been associated with lower birth weight in epidemiologic studies. This association could be attributable to glomerular filtration rate (GFR), which is related to PFAS concentration and birth weight. We used a physiologically based pharmacokinetic (PBPK) model of pregnancy to assess how much of the PFAS-birth weight association observed in epidemiologic studies might be attributable to GFR. We modified a PBPK model to reflect the association of GFR with birth weight (estimated from three studies of GFR and birth weight) and used it to simulate PFAS concentrations in maternal and cord plasma. The model was run 250,000 times, with variation in parameters, to simulate a population. Simulated data were analyzed to evaluate the association between PFAS levels and birth weight due to GFR. We compared simulated estimates with those from a meta-analysis of epidemiologic data. The reduction in birth weight for each 1-ng/mL increase in simulated cord plasma for perfluorooctane sulfonate (PFOS) was 2.72 g (95% CI: -3.40, -2.04), and for perfluorooctanoic acid (PFOA) was 7.13 g (95% CI: -8.46, -5.80); results based on maternal plasma at term were similar. Results were sensitive to variations in PFAS level distributions and the strength of the GFR-birth weight association. In comparison, our meta-analysis of epidemiologic studies suggested that each 1-ng/mL increase in prenatal PFOS and PFOA levels was associated with 5.00 g (95% CI: -21.66, -7.78) and 14.72 g (95% CI: -8.92, -1.09) reductions in birth weight, respectively. Results of our simulations suggest that a substantial proportion of the association between prenatal PFAS and birth weight may be attributable to confounding by GFR and that confounding by GFR may be more important in studies with sample collection later in pregnancy.

  18. Synovial tissue research

    DEFF Research Database (Denmark)

    Orr, Carl; Sousa, Elsa; Boyle, David L

    2017-01-01

    The synovium is the major target tissue of inflammatory arthritides such as rheumatoid arthritis. The study of synovial tissue has advanced considerably throughout the past few decades from arthroplasty and blind needle biopsy to the use of arthroscopic and ultrasonographic technologies that enable...... easier visualization and improve the reliability of synovial biopsies. Rapid progress has been made in using synovial tissue to study disease pathogenesis, to stratify patients, to discover biomarkers and novel targets, and to validate therapies, and this progress has been facilitated by increasingly...... diverse and sophisticated analytical and technological approaches. In this Review, we describe these approaches, and summarize how their use in synovial tissue research has improved our understanding of rheumatoid arthritis and identified candidate biomarkers that could be used in disease diagnosis...

  19. Tissue-engineered trachea: History, problems and the future

    OpenAIRE

    Tan, Qiang; Steiner, Rudolf; Hoerstrup, Simon P.; Weder, Walter

    2017-01-01

    This review tries to summarize the efforts over the past 20 years to construct a tissue-engineered trachea. After illustrating the main technical bottlenecks faced nowadays, we discuss what might be the solutions to these bottlenecks. You may find out why the focus in this research field shifts dramatically from the construction of a tubular cartilage tissue to reepithelialization and revascularization of the prosthesis. In the end we propose a novel concept of ‘in vivo bioreactor', defined a...

  20. Students' Academic Performance: Academic Effort Is an Intervening ...

    African Journals Online (AJOL)

    PROMOTING ACCESS TO AFRICAN RESEARCH ... Students' Academic Performance: Academic Effort Is an Intervening Variable ... This study was designed to seek explanations for differences in academic performance among junior ...

  1. A critical evalluation of internal revenue generating efforts of some ...

    African Journals Online (AJOL)

    Their bad financial state has robbed our rural areas of ... electricity, food production, staff welfare and general condition of living in the rural areas. This ugly ... Inspite of these efforts by successive governments, the problem continues to persist.

  2. Reviewing efforts in global forest conservation for sustainable forest ...

    African Journals Online (AJOL)

    Reviewing efforts in global forest conservation for sustainable forest management: The World Wide Fund (WWF) case study. ... Global Journal of Pure and Applied Sciences. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current ...

  3. NUCLEAR NONPROLIFERATION: U.S. Efforts to Combat Nuclear Smuggling

    National Research Council Canada - National Science Library

    2002-01-01

    ...) information about efforts to combat nuclear smuggling at U.S. borders. My statement today is based on the results of our May 16, 2002, report on this subject1 and information we obtained from the U.S...

  4. Overview of NASA/OAST efforts related to manufacturing technology

    Science.gov (United States)

    Saunders, N. T.

    1976-01-01

    An overview of some of NASA's current efforts related to manufacturing technology and some possible directions for the future are presented. The topics discussed are: computer-aided design, composite structures, and turbine engine components.

  5. AMRDEC's HWIL Synthetic Environment Development Efforts for LADAR Sensors

    National Research Council Canada - National Science Library

    Kim, Hajin J; Cornell, Michael C; Naumann, Charles B

    2004-01-01

    .... With the emerging sensor/electronics technology LADAR sensors are becoming more viable option as an integral part of weapon systems, and AMCOM has been expending efforts to develop the capabilities...

  6. Cognitive dissonance in children: justification of effort or contrast?

    Science.gov (United States)

    Alessandri, Jérôme; Darcheville, Jean-Claude; Zentall, Thomas R

    2008-06-01

    Justification of effort is a form of cognitive dissonance in which the subjective value of an outcome is directly related to the effort that went into obtaining it. However, it is likely that in social contexts (such as the requirements for joining a group) an inference can be made (perhaps incorrectly) that an outcome that requires greater effort to obtain in fact has greater value. Here we present evidence that a cognitive dissonance effect can be found in children under conditions that offer better control for the social value of the outcome. This effect is quite similar to contrast effects that recently have been studied in animals. We suggest that contrast between the effort required to obtain the outcome and the outcome itself provides a more parsimonious account of this phenomenon and perhaps other related cognitive dissonance phenomena as well. Research will be needed to identify cognitive dissonance processes that are different from contrast effects of this kind.

  7. Students Collaborating to Undertake Tracking Efforts for Sturgeon(SCUTES)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Students Collaborating to Undertake Tracking Efforts for Sturgeon (SCUTES) is a collaboration between NOAA Fisheries, sturgeon researchers, and teachers/educators in...

  8. A technique for estimating maximum harvesting effort in a stochastic ...

    Indian Academy of Sciences (India)

    Unknown

    Estimation of maximum harvesting effort has a great impact on the ... fluctuating environment has been developed in a two-species competitive system, which shows that under realistic .... The existence and local stability properties of the equi-.

  9. Book Promotion Efforts in Select Nigerian Newspapers Okere ...

    African Journals Online (AJOL)

    Mrs Afam

    them make informed purchase decision. Hitherto, the ... for product promotion compared to the efforts of manufacturers of consumer goods and other .... The extent of promotion done by a publisher affects greatly the rate of order placed.

  10. Effort-Based Decision-Making in Schizophrenia.

    Science.gov (United States)

    Culbreth, Adam J; Moran, Erin K; Barch, Deanna M

    2018-08-01

    Motivational impairment has long been associated with schizophrenia but the underlying mechanisms are not clearly understood. Recently, a small but growing literature has suggested that aberrant effort-based decision-making may be a potential contributory mechanism for motivational impairments in psychosis. Specifically, multiple reports have consistently demonstrated that individuals with schizophrenia are less willing than healthy controls to expend effort to obtain rewards. Further, this effort-based decision-making deficit has been shown to correlate with severity of negative symptoms and level of functioning, in many but not all studies. In the current review, we summarize this literature and discuss several factors that may underlie aberrant effort-based decision-making in schizophrenia.

  11. Muscle strength, working capacity and effort in patients with fibromyalgia

    DEFF Research Database (Denmark)

    Nørregaard, J; Bülow, P M; Lykkegaard, J J

    1997-01-01

    exercise capacity, work status and psychometric scoring (SCL-90-R) were correlated. The fibromyalgia patients exhibited significant reduction in voluntary muscle strength of the knee and elbow, flexors and extensors in the order of 20-30%. However, the coefficient of variation was higher among patients......, thus indicating lower effort. The physical performance during an ergometer test corresponded to a maximal oxygen consumption of 21 ml/kg-1 x min-1. The maximal increase in heart rate was only 63% (44-90%) of the predicted increase. Degree of effort or physical capacity did not correlate to psychometric...... scores. Work status was related to psychometric scoring, but not to physical capacity or effort. In conclusion, we found a low degree of effort but near normal physical capacity in the fibromyalgia patients....

  12. When expectation confounds iconic memory.

    Science.gov (United States)

    Bachmann, Talis; Aru, Jaan

    2016-10-01

    In response to the methodological criticism (Bachmann & Aru, 2015) of the interpretation of their earlier experimental results (Mack, Erol, & Clarke, 2015) Mack, Erol, Clarke, and Bert (2016) presented new results that they interpret again in favor of the stance that an attention-free phenomenal iconic store does not exist. Here we once more question their conclusions. When their subjects were unexpectedly asked to report the letters instead of the post-cued circles in the 101th trial where letters were actually absent, they likely failed to see the empty display area because prior experience with letters in the preceding trials produced expectancy based illusory experience of letter-like objects. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Optical tomography of tissues

    International Nuclear Information System (INIS)

    Zimnyakov, D A; Tuchin, Valerii V

    2002-01-01

    Methods of optical tomography of biological tissues are considered, which include pulse-modulation and frequency-modulation tomography, diffusion tomography with the use of cw radiation sources, optical coherent tomography, speckle-correlation tomography of nonstationary media, and optoacoustic tomography. The method for controlling the optical properties of tissues is studied from the point of view of increasing a probing depth in optical coherent tomography. The modern state and prospects of the development of optical tomography are discussed. (review)

  14. Self-managed working time and employee effort: Microeconometric evidence

    OpenAIRE

    Beckmann, Michael; Cornelissen, Thomas

    2014-01-01

    Based on German individual-level panel data, this paper empirically examines the impact of self-managed working time (SMWT) on employee effort. Theoretically, workers may respond positively or negatively to having control over their own working hours, depending on whether SMWT increases work morale, induces reciprocal work intensification, or encourages employee shirking. We find that SMWT employees exert higher effort levels than employees with fixed working hours, but after accounting for o...

  15. VIOLENCE IN MARKETING COMMUNICATION EFFORTS OF FASHION BRANDS: SHOCKVERTISING

    OpenAIRE

    BAYAZIT, Zeynep; PANAYIRCI, Uğur Cevdet

    2016-01-01

    Contemporary social and technological changes inevitably affect consumer behaviour. Today’s customer is savvy, have no time and hard to persuade. This new relationship between customers and brands has a deeper impact on competitive industries such as fashion. Fashion brands are eager to adopt shocking themes for their marketing communication efforts in order to emotionally affect and challenge consumers. Aim of this study is to study with a critical perspective the advertisement efforts of fa...

  16. Communication Breakdown: Unraveling the Islamic States Media Efforts

    Science.gov (United States)

    2016-10-01

    Communication Breakdown: Unraveling the Islamic State’s Media Efforts Daniel Milton Communication Breakdown: Unraveling the Islamic State’s Media ...production arm of central media office).28 The high level of communication between the central media office and the satellite offices illustrates the tension...and discussed by the mass media . Those products are likely important to the group’s recruitment efforts, but clearly it is trying to portray itself

  17. Shell Inspection History and Current CMM Inspection Efforts

    Energy Technology Data Exchange (ETDEWEB)

    Montano, Joshua Daniel [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-01-26

    The following report provides a review of past and current CMM Shell Inspection efforts. Calibration of the Sheffield rotary contour gauge has expired and the primary inspector, Matthew Naranjo, has retired. Efforts within the Inspection team are transitioning from maintaining and training new inspectors on Sheffield to off-the-shelf CMM technology. Although inspection of a shell has many requirements, the scope of the data presented in this report focuses on the inner contour, outer contour, radial wall thickness and mass comparisons.

  18. Motivation and effort in individuals with social anhedonia.

    Science.gov (United States)

    McCarthy, Julie M; Treadway, Michael T; Blanchard, Jack J

    2015-06-01

    It has been proposed that anhedonia may, in part, reflect difficulties in reward processing and effortful decision making. The current study aimed to replicate previous findings of effortful decision making deficits associated with elevated anhedonia and expand upon these findings by investigating whether these decision making deficits are specific to elevated social anhedonia or are also associated with elevated positive schizotypy characteristics. The current study compared controls (n=40) to individuals elevated on social anhedonia (n=30), and individuals elevated on perceptual aberration/magical ideation (n=30) on the Effort Expenditure for Rewards Task (EEfRT). Across groups, participants chose a higher proportion of hard tasks with increasing probability of reward and reward magnitude, demonstrating sensitivity to probability and reward values. Contrary to our expectations, when the probability of reward was most uncertain (50% probability), at low and medium reward values, the social anhedonia group demonstrated more effortful decision making than either individuals high in positive schizotypy or controls. The positive schizotypy group only differed from controls (making less effortful choices than controls) when reward probability was lowest (12%) and the magnitude of reward was the smallest. Our results suggest that social anhedonia is related to intact motivation and effort for monetary rewards, but that individuals with this characteristic display a unique and perhaps inefficient pattern of effort allocation when the probability of reward is most uncertain. Future research is needed to better understand effortful decision making and the processing of reward across a range of individual difference characteristics. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Working from Home - What is the Effect on Employees' Effort?

    OpenAIRE

    Rupietta, Kira; Beckmann, Michael

    2016-01-01

    This paper investigates how working from home affects employees' work effort. Employees, who have the possibility to work from home, have a high autonomy in scheduling their work and therefore are assumed to have a higher intrinsic motivation. Thus, we expect working from home to positively influence work effort of employees. For the empirical analysis we use the German Socio-Economic Panel (SOEP). To account for self-selection into working locations we use an instrumental variable (IV) estim...

  20. Goddard Technology Efforts to Improve Space Borne Laser Reliability

    Science.gov (United States)

    Heaps, William S.

    2006-01-01

    In an effort to reduce the risk, perceived and actual, of employing instruments containing space borne lasers NASA initiated the Laser Risk Reduction Program (LRRP) in 2001. This program managed jointly by NASA Langley and NASA Goddard and employing lasers researchers from government, university and industrial labs is nearing the conclusion of its planned 5 year duration. This paper will describe some of the efforts and results obtained by the Goddard half of the program.

  1. Control and Effort Costs Influence the Motivational Consequences of Choice

    Directory of Open Access Journals (Sweden)

    Holly Sullivan-Toole

    2017-05-01

    Full Text Available The act of making a choice, apart from any outcomes the choice may yield, has, paradoxically, been linked to both the enhancement and the detriment of intrinsic motivation. Research has implicated two factors in potentially mediating these contradictory effects: the personal control conferred by a choice and the costs associated with a choice. Across four experiments, utilizing a physical effort task disguised as a simple video game, we systematically varied costs across two levels of physical effort requirements (Low-Requirement, High-Requirement and control over effort costs across three levels of choice (Free-Choice, Restricted-Choice, and No-Choice to disambiguate how these factors affect the motivational consequences of choosing within an effortful task. Together, our results indicated that, in the face of effort requirements, illusory control alone may not sufficiently enhance perceptions of personal control to boost intrinsic motivation; rather, the experience of actual control may be necessary to overcome effort costs and elevate performance. Additionally, we demonstrated that conditions of illusory control, while otherwise unmotivating, can through association with the experience of free-choice, be transformed to have a positive effect on motivation.

  2. Job Satisfaction, Effort, and Performance: A Reasoned Action Perspective

    Directory of Open Access Journals (Sweden)

    Icek Ajzen

    2011-12-01

    Full Text Available In this article the author takes issue with the recurrent reliance on job satisfaction to explain job-related effort and performance.  The disappointing findings in this tradition are explained by lack of compatibility between job satisfaction–-a very broad attitude–-and the more specific effort and performance criteria.  Moreover, attempts to apply the expectancy-value model of attitude to explore the determinants of effort and performance suffer from reliance on unrepresentative sets of beliefs about the likely consequences of these behaviors.  The theory of planned behavior (Ajzen, 1991, 2012, with its emphasis on the proximal antecedents of job effort and performance, is offered as an alternative.  According to the theory, intentions to exert effort and to attain a certain performance level are determined by attitudes, subjective norms, and perceptions of control in relation to these behaviors; and these variables, in turn, are a function of readily accessible beliefs about the likely outcomes of effort and performance, about the normative expectations of important others, and about factors that facilitate or hinder effective performance.

  3. The influence of music on mental effort and driving performance.

    Science.gov (United States)

    Ünal, Ayça Berfu; Steg, Linda; Epstude, Kai

    2012-09-01

    The current research examined the influence of loud music on driving performance, and whether mental effort mediated this effect. Participants (N=69) drove in a driving simulator either with or without listening to music. In order to test whether music would have similar effects on driving performance in different situations, we manipulated the simulated traffic environment such that the driving context consisted of both complex and monotonous driving situations. In addition, we systematically kept track of drivers' mental load by making the participants verbally report their mental effort at certain moments while driving. We found that listening to music increased mental effort while driving, irrespective of the driving situation being complex or monotonous, providing support to the general assumption that music can be a distracting auditory stimulus while driving. However, drivers who listened to music performed as well as the drivers who did not listen to music, indicating that music did not impair their driving performance. Importantly, the increases in mental effort while listening to music pointed out that drivers try to regulate their mental effort as a cognitive compensatory strategy to deal with task demands. Interestingly, we observed significant improvements in driving performance in two of the driving situations. It seems like mental effort might mediate the effect of music on driving performance in situations requiring sustained attention. Other process variables, such as arousal and boredom, should also be incorporated to study designs in order to reveal more on the nature of how music affects driving. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. The RBANS Effort Index: base rates in geriatric samples.

    Science.gov (United States)

    Duff, Kevin; Spering, Cynthia C; O'Bryant, Sid E; Beglinger, Leigh J; Moser, David J; Bayless, John D; Culp, Kennith R; Mold, James W; Adams, Russell L; Scott, James G

    2011-01-01

    The Effort Index (EI) of the RBANS was developed to assist clinicians in discriminating patients who demonstrate good effort from those with poor effort. However, there are concerns that older adults might be unfairly penalized by this index, which uses uncorrected raw scores. Using five independent samples of geriatric patients with a broad range of cognitive functioning (e.g., cognitively intact, nursing home residents, probable Alzheimer's disease), base rates of failure on the EI were calculated. In cognitively intact and mildly impaired samples, few older individuals were classified as demonstrating poor effort (e.g., 3% in cognitively intact). However, in the more severely impaired geriatric patients, over one third had EI scores that fell above suggested cutoff scores (e.g., 37% in nursing home residents, 33% in probable Alzheimer's disease). In the cognitively intact sample, older and less educated patients were more likely to have scores suggestive of poor effort. Education effects were observed in three of the four clinical samples. Overall cognitive functioning was significantly correlated with EI scores, with poorer cognition being associated with greater suspicion of low effort. The current results suggest that age, education, and level of cognitive functioning should be taken into consideration when interpreting EI results and that significant caution is warranted when examining EI scores in elders suspected of having dementia.

  5. Identifying cis-mediators for trans-eQTLs across many human tissues using genomic mediation analysis.

    Science.gov (United States)

    Yang, Fan; Wang, Jiebiao; Pierce, Brandon L; Chen, Lin S

    2017-11-01

    The impact of inherited genetic variation on gene expression in humans is well-established. The majority of known expression quantitative trait loci (eQTLs) impact expression of local genes ( cis -eQTLs). More research is needed to identify effects of genetic variation on distant genes ( trans -eQTLs) and understand their biological mechanisms. One common trans -eQTLs mechanism is "mediation" by a local ( cis ) transcript. Thus, mediation analysis can be applied to genome-wide SNP and expression data in order to identify transcripts that are " cis -mediators" of trans -eQTLs, including those " cis -hubs" involved in regulation of many trans -genes. Identifying such mediators helps us understand regulatory networks and suggests biological mechanisms underlying trans -eQTLs, both of which are relevant for understanding susceptibility to complex diseases. The multitissue expression data from the Genotype-Tissue Expression (GTEx) program provides a unique opportunity to study cis -mediation across human tissue types. However, the presence of complex hidden confounding effects in biological systems can make mediation analyses challenging and prone to confounding bias, particularly when conducted among diverse samples. To address this problem, we propose a new method: Genomic Mediation analysis with Adaptive Confounding adjustment (GMAC). It enables the search of a very large pool of variables, and adaptively selects potential confounding variables for each mediation test. Analyses of simulated data and GTEx data demonstrate that the adaptive selection of confounders by GMAC improves the power and precision of mediation analysis. Application of GMAC to GTEx data provides new insights into the observed patterns of cis -hubs and trans -eQTL regulation across tissue types. © 2017 Yang et al.; Published by Cold Spring Harbor Laboratory Press.

  6. Electrospun nanofiber scaffolds: engineering soft tissues

    International Nuclear Information System (INIS)

    Kumbar, S G; Nukavarapu, S P; Laurencin, C T; James, R

    2008-01-01

    Electrospinning has emerged to be a simple, elegant and scalable technique to fabricate polymeric nanofibers. Pure polymers as well as blends and composites of both natural and synthetics have been successfully electrospun into nanofiber matrices. Physiochemical properties of nanofiber matrices can be controlled by manipulating electrospinning parameters to meet the requirements of a specific application. Such efforts include the fabrication of fiber matrices containing nanofibers, microfibers, combination of nano-microfibers and also different fiber orientation/alignments. Polymeric nanofiber matrices have been extensively investigated for diversified uses such as filtration, barrier fabrics, wipes, personal care, biomedical and pharmaceutical applications. Recently electrospun nanofiber matrices have gained a lot of attention, and are being explored as scaffolds in tissue engineering due to their properties that can modulate cellular behavior. Electrospun nanofiber matrices show morphological similarities to the natural extra-cellular matrix (ECM), characterized by ultrafine continuous fibers, high surface-to-volume ratio, high porosity and variable pore-size distribution. Efforts have been made to modify nanofiber surfaces with several bioactive molecules to provide cells with the necessary chemical cues and a more in vivo like environment. The current paper provides an overlook on such efforts in designing nanofiber matrices as scaffolds in the regeneration of various soft tissues including skin, blood vessel, tendon/ligament, cardiac patch, nerve and skeletal muscle

  7. Electrospun nanofiber scaffolds: engineering soft tissues

    Energy Technology Data Exchange (ETDEWEB)

    Kumbar, S G; Nukavarapu, S P; Laurencin, C T [Department of Orthopaedic Surgery, University of Virginia, VA 22908 (United States); James, R [Department of Biomedical Engineering, University of Virginia, VA 22908 (United States)], E-mail: laurencin@virginia.edu

    2008-09-01

    Electrospinning has emerged to be a simple, elegant and scalable technique to fabricate polymeric nanofibers. Pure polymers as well as blends and composites of both natural and synthetics have been successfully electrospun into nanofiber matrices. Physiochemical properties of nanofiber matrices can be controlled by manipulating electrospinning parameters to meet the requirements of a specific application. Such efforts include the fabrication of fiber matrices containing nanofibers, microfibers, combination of nano-microfibers and also different fiber orientation/alignments. Polymeric nanofiber matrices have been extensively investigated for diversified uses such as filtration, barrier fabrics, wipes, personal care, biomedical and pharmaceutical applications. Recently electrospun nanofiber matrices have gained a lot of attention, and are being explored as scaffolds in tissue engineering due to their properties that can modulate cellular behavior. Electrospun nanofiber matrices show morphological similarities to the natural extra-cellular matrix (ECM), characterized by ultrafine continuous fibers, high surface-to-volume ratio, high porosity and variable pore-size distribution. Efforts have been made to modify nanofiber surfaces with several bioactive molecules to provide cells with the necessary chemical cues and a more in vivo like environment. The current paper provides an overlook on such efforts in designing nanofiber matrices as scaffolds in the regeneration of various soft tissues including skin, blood vessel, tendon/ligament, cardiac patch, nerve and skeletal muscle.

  8. Effort-reward imbalance at work and self-rated health of Las Vegas hotel room cleaners.

    Science.gov (United States)

    Krause, Niklas; Rugulies, Reiner; Maslach, Christina

    2010-04-01

    This study investigates the relationship between effort-reward-imbalance (ERI) at work and self-rated health (SF-36) among 941 Las Vegas hotel room cleaners (99% female, 84% immigrant). Logistic regression models adjust for age, health behaviors, physical workload and other potential confounders. 50% reported ERI and 60% poor or fair general health. Significant associations were found between ERI and all SF-36 health measures. Workers in the upper quartile of the efforts/rewards ratio were 2-5 times more likely to experience poor or fair general health, low physical function, high levels of pain, fatigue, and role limitations due to physical and mental health problems. The cross-sectional design limits causal interpretation of these associations. However, the development of interventions to reduce ERI and to improve general health among room cleaners deserves high priority considering that both high ERI and low self-rated health have predicted chronic diseases and mortality in prospective studies. (c) 2009 Wiley-Liss, Inc.

  9. Growing tissues in real and simulated microgravity: new methods for tissue engineering.

    Science.gov (United States)

    Grimm, Daniela; Wehland, Markus; Pietsch, Jessica; Aleshcheva, Ganna; Wise, Petra; van Loon, Jack; Ulbrich, Claudia; Magnusson, Nils E; Infanger, Manfred; Bauer, Johann

    2014-12-01

    Tissue engineering in simulated (s-) and real microgravity (r-μg) is currently a topic in Space medicine contributing to biomedical sciences and their applications on Earth. The principal aim of this review is to highlight the advances and accomplishments in the field of tissue engineering that could be achieved by culturing cells in Space or by devices created to simulate microgravity on Earth. Understanding the biology of three-dimensional (3D) multicellular structures is very important for a more complete appreciation of in vivo tissue function and advancing in vitro tissue engineering efforts. Various cells exposed to r-μg in Space or to s-μg created by a random positioning machine, a 2D-clinostat, or a rotating wall vessel bioreactor grew in the form of 3D tissues. Hence, these methods represent a new strategy for tissue engineering of a variety of tissues, such as regenerated cartilage, artificial vessel constructs, and other organ tissues as well as multicellular cancer spheroids. These aggregates are used to study molecular mechanisms involved in angiogenesis, cancer development, and biology and for pharmacological testing of, for example, chemotherapeutic drugs or inhibitors of neoangiogenesis. Moreover, they are useful for studying multicellular responses in toxicology and radiation biology, or for performing coculture experiments. The future will show whether these tissue-engineered constructs can be used for medical transplantations. Unveiling the mechanisms of microgravity-dependent molecular and cellular changes is an up-to-date requirement for improving Space medicine and developing new treatment strategies that can be translated to in vivo models while reducing the use of laboratory animals.

  10. Bioreactors in tissue engineering - principles, applications and commercial constraints.

    Science.gov (United States)

    Hansmann, Jan; Groeber, Florian; Kahlig, Alexander; Kleinhans, Claudia; Walles, Heike

    2013-03-01

    Bioreactor technology is vital for tissue engineering. Usually, bioreactors are used to provide a tissue-specific physiological in vitro environment during tissue maturation. In addition to this most obvious application, bioreactors have the potential to improve the efficiency of the overall tissue-engineering concept. To date, a variety of bioreactor systems for tissue-specific applications have been developed. Of these, some systems are already commercially available. With bioreactor technology, various functional tissues of different types were generated and cultured in vitro. Nevertheless, these efforts and achievements alone have not yet led to many clinically successful tissue-engineered implants. We review possible applications for bioreactor systems within a tissue-engineering process and present basic principles and requirements for bioreactor development. Moreover, the use of bioreactor systems for the expansion of clinically relevant cell types is addressed. In contrast to cell expansion, for the generation of functional three-dimensional tissue equivalents, additional physical cues must be provided. Therefore, bioreactors for musculoskeletal tissue engineering are discussed. Finally, bioreactor technology is reviewed in the context of commercial constraints. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Reproductive performance and gestational effort in relation to dietary fatty acids in guinea pigs.

    Science.gov (United States)

    Nemeth, Matthias; Millesi, Eva; Siutz, Carina; Wagner, Karl-Heinz; Quint, Ruth; Wallner, Bernard

    2017-01-01

    Dietary saturated (SFAs) and polyunsaturated (PUFAs) fatty acids can highly affect reproductive functions by providing additional energy, modulating the biochemical properties of tissues, and hormone secretions. In precocial mammals such as domestic guinea pigs the offspring is born highly developed. Gestation might be the most critical reproductive period in this species and dietary fatty acids may profoundly influence the gestational effort. We therefore determined the hormonal status at conception, the reproductive success, and body mass changes during gestation in guinea pigs maintained on diets high in PUFAs or SFAs, or a control diet. The diets significantly affected the females' plasma fatty acid status at conception, while cortisol and estrogen levels did not differ among groups. SFA females exhibited a significantly lower body mass and litter size, while the individual birth mass of pups did not differ among groups and a general higher pup mortality rate in larger litters was diminished by PUFAs and SFAs. The gestational effort, determined by a mother's body mass gain during gestation, increased with total litter mass, whereas this increase was lowest in SFA and highest in PUFA individuals. The mother's body mass after parturition did not differ among groups and was positively affected by the total litter mass in PUFA females. While SFAs reduce the litter size, but also the gestational effort as a consequence, PUFA supplementation may contribute to an adjustment of energy accumulations to the total litter mass, which may both favor a mother's body condition at parturition and perhaps increase the offspring survival at birth.

  12. [Connective tissue and inflammation].

    Science.gov (United States)

    Jakab, Lajos

    2014-03-23

    The author summarizes the structure of the connective tissues, the increasing motion of the constituents, which determine the role in establishing the structure and function of that. The structure and function of the connective tissue are related to each other in the resting as well as inflammatory states. It is emphasized that cellular events in the connective tissue are part of the defence of the organism, the localisation of the damage and, if possible, the maintenance of restitutio ad integrum. The organism responds to damage with inflammation, the non specific immune response, as well as specific, adaptive immunity. These processes are located in the connective tissue. Sterile and pathogenic inflammation are relatively similar processes, but inevitable differences are present, too. Sialic acids and glycoproteins containing sialic acids have important roles, and the role of Siglecs is also highlighted. Also, similarities and differences in damages caused by pathogens and sterile agents are briefly summarized. In addition, the roles of adhesion molecules linked to each other, and the whole event of inflammatory processes are presented. When considering practical consequences it is stressed that the structure (building up) of the organism and the defending function of inflammation both have fundamental importance. Inflammation has a crucial role in maintaining the integrity and the unimpaired somato-psychological state of the organism. Thus, inflammation serves as a tool of organism identical with the natural immune response, inseparably connected with the specific, adaptive immune response. The main events of the inflammatory processes take place in the connective tissue.

  13. Autopsy Tissue Program

    International Nuclear Information System (INIS)

    Fox, T.; Tietjen, G.

    1979-01-01

    The Autopsy Tissue Program was begun in 1960. To date, tissues on 900 or more persons in 7 geographic regions have been collected and analyzed for plutonium content. The tissues generally consist of lung, liver, kidney, lymph, bone, and gonadal tissue for each individual. The original objective of the program was to determine the level of plutonium in human tissues due solely to fall-out from weapons testing. The baseline thus established was to be used to evaluate future changes. From the first, this program was beset with chemical and statistical difficulties. Many factors whose effects were not recognized and not planned for were found later to be important. Privacy and ethical considerations hindered the gathering of adequate data. Since the chemists were looking for amounts of plutonium very close to background, possible contamination was a very real problem. Widely used chemical techniques introduced a host of statistical problems. The difficulties encountered touch on areas common to large data sets, unusual outlier detection methods, minimum detection limits, problems with Aliquot sizes, and time-trends in the data. The conclusions point out areas to which the biologists will have to devote much more careful attention than was believed

  14. Morphology of urethral tissues

    Science.gov (United States)

    Müller, Bert; Schulz, Georg; Herzen, Julia; Mushkolaj, Shpend; Bormann, Therese; Beckmann, Felix; Püschel, Klaus

    2010-09-01

    Micro computed tomography has been developed to a powerful technique for the characterization of hard and soft human and animal tissues. Soft tissues including the urethra, however, are difficult to be analyzed, since the microstructures of interest exhibit X-ray absorption values very similar to the surroundings. Selective staining using highly absorbing species is a widely used approach, but associated with significant tissue modification. Alternatively, one can suitably embed the soft tissue, which requires the exchange of water. Therefore, the more recently developed phase contrast modes providing much better contrast of low X-ray absorbing species are especially accommodating in soft tissue characterization. The present communication deals with the morphological characterization of sheep, pig and human urethras on the micrometer scale taking advantage of micro computed tomography in absorption and phase contrast modes. The performance of grating-based tomography is demonstrated for freshly explanted male and female urethras in saline solution. The micro-morphology of the urethra is important to understand how the muscles close the urethra to reach continence. As the number of incontinent patients is steadily increasing, the function under static and, more important, under stress conditions has to be uncovered for the realization of artificial urinary sphincters, which needs sophisticated, biologically inspired concepts to become nature analogue.

  15. Anticipated emotions and effort allocation in weight goal striving.

    Science.gov (United States)

    Nelissen, Rob M A; de Vet, Emely; Zeelenberg, Marcel

    2011-02-01

    This study aimed to investigate the influence of anticipated emotions on preventive health behaviour if specified at the level of behavioural outcomes. Consistent with predictions from a recently developed model of goal pursuit, we hypothesized that the impact of emotions on effort levels depended on the perceived proximity to the goal. Participants with weight-loss intentions were randomly selected from an Internet panel and completed questionnaires at three points in time, baseline (T1; N= 725), 2 weeks later at T2 (N= 582) and again 2 months later at T3 (N= 528). Questionnaires assessed anticipated emotions (at T1) and experienced emotions (at T2) towards goal attainment and non-attainment. Goal proximity, goal desirability, and effort levels in striving for weight loss were assessed at both T1 and T2. Current and target weights were reported at all three assessments. In line with predictions, we found that negative anticipated emotions towards goal non-attainment resulted in increased effort but only if people perceived themselves in close proximity to their goal. Effort, in turn, predicted weight loss and goal achievement. The current data bear important practical implications as they identify anticipated emotions as targets of behaviour change interventions aimed to stimulate effort in striving for broad, health-related goals like weight loss. ©2010 The British Psychological Society.

  16. Effort sharing in ambitious, global climate change mitigation scenarios

    International Nuclear Information System (INIS)

    Ekholm, Tommi; Soimakallio, Sampo; Moltmann, Sara; Hoehne, Niklas; Syri, Sanna; Savolainen, Ilkka

    2010-01-01

    The post-2012 climate policy framework needs a global commitment to deep greenhouse gas emission cuts. This paper analyzes reaching ambitious emission targets up to 2050, either -10% or -50% from 1990 levels, and how the economic burden from mitigation efforts could be equitably shared between countries. The scenarios indicate a large low-cost mitigation potential in electricity and industry, while reaching low emission levels in international transportation and agricultural emissions might prove difficult. The two effort sharing approaches, Triptych and Multistage, were compared in terms of equitability and coherence. Both approaches produced an equitable cost distribution between countries, with least developed countries having negative or low costs and more developed countries having higher costs. There is, however, no definitive solution on how the costs should be balanced equitably between countries. Triptych seems to be yet more coherent than other approaches, as it can better accommodate national circumstances. Last, challenges and possible hindrances to effective mitigation and equitable effort sharing are presented. The findings underline the significance of assumptions behind effort sharing on mitigation potentials and current emissions, the challenge of sharing the effort with uncertain future allowance prices and how inefficient markets might undermine the efficiency of a cap-and-trade system.

  17. Climate Data Initiative: A Geocuration Effort to Support Climate Resilience

    Science.gov (United States)

    Ramachandran, Rahul; Bugbee, Kaylin; Tilmes, Curt; Pinheiro Privette, Ana

    2015-01-01

    Curation is traditionally defined as the process of collecting and organizing information around a common subject matter or a topic of interest and typically occurs in museums, art galleries, and libraries. The task of organizing data around specific topics or themes is a vibrant and growing effort in the biological sciences but to date this effort has not been actively pursued in the Earth sciences. In this paper, we introduce the concept of geocuration and define it as the act of searching, selecting, and synthesizing Earth science data/metadata and information from across disciplines and repositories into a single, cohesive, and useful compendium We present the Climate Data Initiative (CDI) project as an exemplar example. The CDI project is a systematic effort to manually curate and share openly available climate data from various federal agencies. CDI is a broad multi-agency effort of the U.S. government and seeks to leverage the extensive existing federal climate-relevant data to stimulate innovation and private-sector entrepreneurship to support national climate-change preparedness. We describe the geocuration process used in CDI project, lessons learned, and suggestions to improve similar geocuration efforts in the future.

  18. The effect of sleep loss on next day effort.

    Science.gov (United States)

    Engle-Friedman, Mindy; Riela, Suzanne; Golan, Rama; Ventuneac, Ana M; Davis, Christine M; Jefferson, Angela D; Major, Donna

    2003-06-01

    The study had two primary objectives. The first was to determine whether sleep loss results in a preference for tasks demanding minimal effort. The second was to evaluate the quality of performance when participants, under conditions of sleep loss, have control over task demands. In experiment 1, using a repeated-measures design, 50 undergraduate college students were evaluated, following one night of no sleep loss and one night of sleep loss. The Math Effort Task (MET) presented addition problems via computer. Participants were able to select additions at one of five levels of difficulty. Less-demanding problems were selected and more additions were solved correctly when the participants were subject to sleep loss. In experiment 2, 58 undergraduate college students were randomly assigned to a no sleep deprivation or a sleep deprivation condition. Sleep-deprived participants selected less-demanding problems on the MET. Percentage correct on the MET was equivalent for both the non-sleep-deprived and sleep-deprived groups. On a task selection question, the sleep-deprived participants also selected significantly less-demanding non-academic tasks. Increased sleepiness, fatigue, and reaction time were associated with the selection of less difficult tasks. Both groups of participants reported equivalent effort expenditures; sleep-deprived participants did not perceive a reduction in effort. These studies demonstrate that sleep loss results in the choice of low-effort behavior that helps maintain accurate responding.

  19. Divided attention and mental effort after severe traumatic brain injury.

    Science.gov (United States)

    Azouvi, Philippe; Couillet, Josette; Leclercq, Michel; Martin, Yves; Asloun, Sybille; Rousseaux, Marc

    2004-01-01

    The aim of this study was to assess dual-task performance in TBI patients, under different experimental conditions, with or without explicit emphasis on one of two tasks. Results were compared with measurement of the subjective mental effort required to perform each task. Forty-three severe TBI patients at the subacute or chronic phase performed two tasks under single- and dual-task conditions: (a) random generation; (b) visual go-no go reaction time task. Three dual-task conditions were given, requiring either to consider both tasks as equally important or to focus preferentially on one of them. Patients were compared to matched controls. Subjective mental effort was rated on a visual analogic scale. TBI patients showed a disproportionate increase in reaction time in the go-no go task under the dual-task condition. However, they were just as able as controls to adapt performance to the specific instructions about the task to be emphasised. Patients reported significantly higher subjective mental effort, but the variation of mental effort according to task condition was similar to that of controls. These results suggest that the divided attention deficit of TBI patients is related to a reduction in available processing resources rather than an impairment of strategic processes responsible for attentional allocation and switching. The higher level of subjective mental effort may explain why TBI patients frequently complain of mental fatigue, although this subjective complaint seems to be relatively independent of cognitive impairment.

  20. APA efforts in promoting human rights and social justice.

    Science.gov (United States)

    Leong, Frederick T L; Pickren, Wade E; Vasquez, Melba J T

    2017-11-01

    This article reviews the American Psychological Association's (APA) efforts in promoting human rights and social justice. Beginning with a historical review of the conceptualizations of human rights and social justice, the social challenges that have faced the United States over time are discussed in relation to the APA's evolving mission and strategic initiatives enacted through its boards, committees, and directorates. From early efforts on the Board for Social and Ethical Responsibility in Psychology and the Board of Ethnic Minority Affairs to the establishment of the Public Interest Directorate, the APA's efforts to address these human rights and social justice challenges through its task force reports, guidelines, and policies are described. Specifically, issues related to diversity and underrepresentation of minority group members and perspective within the APA, as well as women's issues (prochoice, violence against women, sexualization of young girls, human trafficking) were central to these efforts. These minority groups included racial and ethnic minority groups; immigrants and refugees; lesbian, gay, bisexual, transgendered, and queer individuals; and those with disabilities. Later attention shifted to broader social justice challenges within a public health perspective, such as AIDS, obesity, and violence. Also included is a brief discussion of the Hoffman Report. The article ends with a discussion of future directions for the APA's efforts related to human rights and social justice related to health disparities, violent extremism, social inequality, migration, cultural and racial diversity, and an evidence-based approach to programming. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  1. Acoustic correlate of vocal effort in spasmodic dysphonia.

    Science.gov (United States)

    Eadie, Tanya L; Stepp, Cara E

    2013-03-01

    This study characterized the relationship between relative fundamental frequency (RFF) and listeners' perceptions of vocal effort and overall spasmodic dysphonia severity in the voices of 19 individuals with adductor spasmodic dysphonia. Twenty inexperienced listeners evaluated the vocal effort and overall severity of voices using visual analog scales. The squared correlation coefficients (R2) between average vocal effort and overall severity and RFF measures were calculated as a function of the number of acoustic instances used for the RFF estimate (from 1 to 9, of a total of 9 voiced-voiceless-voiced instances). Increases in the number of acoustic instances used for the RFF average led to increases in the variance predicted by the RFF at the first cycle of voicing onset (onset RFF) in the perceptual measures; the use of 6 or more instances resulted in a stable estimate. The variance predicted by the onset RFF for vocal effort (R2 range, 0.06 to 0.43) was higher than that for overall severity (R2 range, 0.06 to 0.35). The offset RFF was not related to the perceptual measures, irrespective of the sample size. This study indicates that onset RFF measures are related to perceived vocal effort in patients with adductor spasmodic dysphonia. These results have implications for measuring outcomes in this population.

  2. An opportunity cost model of subjective effort and task performance

    Science.gov (United States)

    Kurzban, Robert; Duckworth, Angela; Kable, Joseph W.; Myers, Justus

    2013-01-01

    Why does performing certain tasks cause the aversive experience of mental effort and concomitant deterioration in task performance? One explanation posits a physical resource that is depleted over time. We propose an alternate explanation that centers on mental representations of the costs and benefits associated with task performance. Specifically, certain computational mechanisms, especially those associated with executive function, can be deployed for only a limited number of simultaneous tasks at any given moment. Consequently, the deployment of these computational mechanisms carries an opportunity cost – that is, the next-best use to which these systems might be put. We argue that the phenomenology of effort can be understood as the felt output of these cost/benefit computations. In turn, the subjective experience of effort motivates reduced deployment of these computational mechanisms in the service of the present task. These opportunity cost representations, then, together with other cost/benefit calculations, determine effort expended and, everything else equal, result in performance reductions. In making our case for this position, we review alternate explanations both for the phenomenology of effort associated with these tasks and for performance reductions over time. Likewise, we review the broad range of relevant empirical results from across subdisciplines, especially psychology and neuroscience. We hope that our proposal will help to build links among the diverse fields that have been addressing similar questions from different perspectives, and we emphasize ways in which alternate models might be empirically distinguished. PMID:24304775

  3. Climate data initiative: A geocuration effort to support climate resilience

    Science.gov (United States)

    Ramachandran, Rahul; Bugbee, Kaylin; Tilmes, Curt; Privette, Ana Pinheiro

    2016-03-01

    Curation is traditionally defined as the process of collecting and organizing information around a common subject matter or a topic of interest and typically occurs in museums, art galleries, and libraries. The task of organizing data around specific topics or themes is a vibrant and growing effort in the biological sciences but to date this effort has not been actively pursued in the Earth sciences. In this paper, we introduce the concept of geocuration and define it as the act of searching, selecting, and synthesizing Earth science data/metadata and information from across disciplines and repositories into a single, cohesive, and useful collection. We present the Climate Data Initiative (CDI) project as a prototypical example. The CDI project is a systematic effort to manually curate and share openly available climate data from various federal agencies. CDI is a broad multi-agency effort of the U.S. government and seeks to leverage the extensive existing federal climate-relevant data to stimulate innovation and private-sector entrepreneurship to support national climate-change preparedness. We describe the geocuration process used in the CDI project, lessons learned, and suggestions to improve similar geocuration efforts in the future.

  4. Effort sharing in ambitious, global climate change mitigation scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Ekholm, Tommi [TKK Helsinki University of Technology, Espoo (Finland); Soimakallio, Sampo; Syri, Sanna; Savolainen, Ilkka [VTT Technical Research Centre of Finland, P.O. Box 1000, FIN-02044 VTT (Finland); Moltmann, Sara; Hoehne, Niklas [Ecofys Germany GmbH, Cologne (Germany)

    2010-04-15

    The post-2012 climate policy framework needs a global commitment to deep greenhouse gas emission cuts. This paper analyzes reaching ambitious emission targets up to 2050, either or from 1990 levels, and how the economic burden from mitigation efforts could be equitably shared between countries. The scenarios indicate a large low-cost mitigation potential in electricity and industry, while reaching low emission levels in international transportation and agricultural emissions might prove difficult. The two effort sharing approaches, Triptych and Multistage, were compared in terms of equitability and coherence. Both approaches produced an equitable cost distribution between countries, with least developed countries having negative or low costs and more developed countries having higher costs. There is, however, no definitive solution on how the costs should be balanced equitably between countries. Triptych seems to be yet more coherent than other approaches, as it can better accommodate national circumstances. Last, challenges and possible hindrances to effective mitigation and equitable effort sharing are presented. The findings underline the significance of assumptions behind effort sharing on mitigation potentials and current emissions, the challenge of sharing the effort with uncertain future allowance prices and how inefficient markets might undermine the efficiency of a cap-and-trade system. (author)

  5. Literacy And Reward: Teachers’ Effort To Build Children Reading Habit

    Directory of Open Access Journals (Sweden)

    Helena Arisandi Komang Widia

    2018-01-01

    Full Text Available Children at early levels of primary school require appropriate guidance in their initial reading skill. They need to be trained on how reading becomes an enjoyable routine activity. This study aimed at describing teachers’ effort to build children reading habit. This study employed a qualitative descriptive study and conducted at North Bali Bilingual School Bali. The data were collected through observations and interview. The findings of the study showed that there were several activities conducted by the teacher as efforts to build children reading habit. In terms of building students’ reading habit, the teacher used (1 Point-written in Reading Rocket Chart (PRRC, (2 Chip (white, yellow, green for appreciating good behaviour in reading and using English, (3 Certificate, (4 Class Reward, and (5 Free Play Time. With these efforts, it is evident that the students’ literacy improves and they exhibited great enthusiasm in their reading and studying literacy in the classroom.

  6. Overview of NASA Magnet and Linear Alternator Research Efforts

    Science.gov (United States)

    Geng, Steven M.; Niedra, Janis M.; Schwarze, Gene E.

    2005-02-01

    The Department of Energy, Lockheed Martin, Stirling Technology Company, and NASA Glenn Research Center are developing a high-efficiency, 110 watt Stirling Radioisotope Generator (SRG110) for NASA Space Science missions. NASA Glenn is conducting in-house research on rare earth permanent magnets and on linear alternators to assist in developing a free-piston Stirling convertor for the SRG110 and for developing advanced technology. The permanent magnet research efforts include magnet characterization, short-term magnet aging tests, and long-term magnet aging tests. Linear alternator research efforts have begun just recently at GRC with the characterization of a moving iron type linear alternator using GRC's alternator test rig. This paper reports on the progress and future plans of GRC's magnet and linear alternator research efforts.

  7. EFFORTS AND INEQUALITY OF OPPORTUNITIES IN THE BOLIVIAN LABOR MARKET

    Directory of Open Access Journals (Sweden)

    Fátima Rico Encinas

    2016-01-01

    Full Text Available The equitable distribution of income, along with human development indices, is among the factors that differentiate developed from developing countries. In this paper, efforts and other variables related to the circumstances of individuals were quantified and analyzed together with traditional determinants in order to explain inequality in the working population of Bolivia. We estimated econometric models by merging the extended Mincer equation with John Roemer’s theory of Inequality of Opportunity. We find that efforts are important determinants of the levels of wage inequality in the country as well as regional development, labor informality, gender and ethnicity. In this sense, the paper separates the part of wage inequality that may be attributed to situations that are beyond the control of individuals and that can be attributed to conscious decisions. Micro simulations determined that it would be possible to reduce inequality by as much as 21% if it gives people the chance to make similar efforts to improve their wages.

  8. Practitioner's knowledge representation a pathway to improve software effort estimation

    CERN Document Server

    Mendes, Emilia

    2014-01-01

    The main goal of this book is to help organizations improve their effort estimates and effort estimation processes by providing a step-by-step methodology that takes them through the creation and validation of models that are based on their own knowledge and experience. Such models, once validated, can then be used to obtain predictions, carry out risk analyses, enhance their estimation processes for new projects and generally advance them as learning organizations.Emilia Mendes presents the Expert-Based Knowledge Engineering of Bayesian Networks (EKEBNs) methodology, which she has used and adapted during the course of several industry collaborations with different companies world-wide over more than 6 years. The book itself consists of two major parts: first, the methodology's foundations in knowledge management, effort estimation (with special emphasis on the intricacies of software and Web development) and Bayesian networks are detailed; then six industry case studies are presented which illustrate the pra...

  9. Inpo/industry job and task analysis efforts

    International Nuclear Information System (INIS)

    Wigley, W.W.

    1985-01-01

    One of the goals of INPO is to develop and coordinate industrywide programs to improve the education, training and qualification of nuclear utility personnel. To accomplish this goal, INPO's Training and Education Division: conducts periodic evaluations of industry training programs; provides assistance to the industry in developing training programs; manages the accreditation of utility training programs. These efforts are aimed at satisfying the need for training programs for nuclear utility personnel to be performance-based. Performance-based means that training programs provide an incumbent with the skills and knowledge required to safely perform the job. One of the ways that INPO has provided assistance to the industry is through the industrywide job and task analysis effort. I will discuss the job analysis and task analysis processes, the current status of JTA efforts, JTA products and JTA lessons learned

  10. The Relationship between Patient Satisfaction with Service Quality and Survival in Non-Small Cell Lung Cancer - Is Self-Rated Health a Potential Confounder?

    Directory of Open Access Journals (Sweden)

    Christopher G Lis

    Full Text Available Previously we reported that higher patient satisfaction (PS with service quality is associated with favorable survival outcomes in a variety of cancers. However, we cautioned the readers that patients with greater satisfaction might be the ones with better self-rated health (SRH, a well-established prognosticator of cancer survival. In other words, SRH could potentially confound the PS and survival relationship. We investigated this hypothesis in non-small cell lung cancer (NSCLC.778 NSCLC patients (327 males and 451 females; mean age 58.8 years treated at 4 Cancer Treatment Centers of America hospitals between July 2011 and March 2013. PS was measured on a 7-point scale ranging from "completely dissatisfied" to "completely satisfied". SRH was measured on a 7-point scale ranging from "very poor" to "excellent". Both were dichotomized into 2 categories: top box response (7 versus all others (1-6. Patient survival was the primary end point. Cox regression was used to evaluate the association between PS and survival controlling for covariates.74, 70, 232 and 391 patients had stage I, II, III and IV disease respectively. 631 (81.1% patients were "completely satisfied". 184 (23.7% patients had "excellent" SRH. There was a weak but significant correlation between overall PS and SRH (Kendall's tau b = 0.19; p<0.001. On univariate analysis, "completely satisfied" patients had a significantly lower risk of mortality (HR = 0.75; 95% CI: 0.57 to 0.99; p = 0.04. Similarly, patients with "excellent" SRH had a significantly lower risk of mortality (HR = 0.61; 95% CI: 0.46 to 0.81; p = 0.001. On multivariate analysis controlling for stage at diagnosis, treatment history and gender, SRH was found to be a significant predictor of survival (HR = 0.67; 95% CI: 0.50 to 0.89; p = 0.007 while PS was not (HR = 0.86; 95% CI: 0.64 to 1.2; p = 0.32. Among the individual PS items, the only significant independent predictor of survival was "teams communicating with each

  11. Radiation Exposure During Uterine Fibroid Embolization (UFE): A Confounder-Controlled Comparison Between a State-of-the-Art Angiography Unit and a Conventional Angiography unit.

    Science.gov (United States)

    Sommer, Christof-Matthias; Voigt, Wieland; Klapp Oliger, Michel; Schlett, Christopher L; Erpenbach, Stefan; Thomas, Katrina; Hatopp, Andreas; Kurz, Patrick; Richter, Goetz M

    2018-03-01

     To compare radiation exposure of a state-of-the-art and a conventional angiography unit in patients undergoing uterine fibroid embolization (UFE).  Between January 2009 and December 2016, 286 patients underwent UFE in our Interdisciplinary Fibroid Center. The inclusion criteria for this retrospective analysis were first-time transarterial embolization for symptomatic fibroids, bilateral embolization, procedures applying a state-of-the-art (Group 1) or a conventional angiography unit (Group 2), and bilateral technical success with an adequate embolization endpoint after the injection of microspheres. Study endpoints included radiation exposure, major complications, morphological success (MRI), and clinical success (questionnaire on quality-of-life). Propensity score matching controlled for confounders.  The inclusion criteria were met by 58 (Group 1) and 177 (Group 2) patients. After propensity score matching, there was no significant difference between Group 1 (n = 46) and Group 2 (n = 92) regarding age, body-mass index, volume of the dominant fibroid and the uterus, fluoroscopy time, and amount of embolic agent (p ≥ 0.10 each). The dose-area product was significantly lower in Group 1 than in Group 2 (1159.0 cGycm 2 vs. 3123.5 cGycm 2 ; p  0.99). There were no significant differences between both groups regarding shrinkage of the dominant fibroid and the uterus and no relevant differences regarding patient-reported quality-of-life.  A state-of-the-art angiography unit has the potential to reduce radiation exposure in patients undergoing UFE without increasing the risk of major complications and with comparably high morphological and clinical success.   · A state-of-the-art angiography unit potentially reduces radiation exposure in patients undergoing UFE.. · Reduced radiation exposure does not seem to negatively influence the rate of major complications.. · Reduced exposure does not seem to negatively affect morphological and clinical

  12. The Relationship between Patient Satisfaction with Service Quality and Survival in Non-Small Cell Lung Cancer - Is Self-Rated Health a Potential Confounder?

    Science.gov (United States)

    Lis, Christopher G; Patel, Kamal; Gupta, Digant

    2015-01-01

    Previously we reported that higher patient satisfaction (PS) with service quality is associated with favorable survival outcomes in a variety of cancers. However, we cautioned the readers that patients with greater satisfaction might be the ones with better self-rated health (SRH), a well-established prognosticator of cancer survival. In other words, SRH could potentially confound the PS and survival relationship. We investigated this hypothesis in non-small cell lung cancer (NSCLC). 778 NSCLC patients (327 males and 451 females; mean age 58.8 years) treated at 4 Cancer Treatment Centers of America hospitals between July 2011 and March 2013. PS was measured on a 7-point scale ranging from "completely dissatisfied" to "completely satisfied". SRH was measured on a 7-point scale ranging from "very poor" to "excellent". Both were dichotomized into 2 categories: top box response (7) versus all others (1-6). Patient survival was the primary end point. Cox regression was used to evaluate the association between PS and survival controlling for covariates. 74, 70, 232 and 391 patients had stage I, II, III and IV disease respectively. 631 (81.1%) patients were "completely satisfied". 184 (23.7%) patients had "excellent" SRH. There was a weak but significant correlation between overall PS and SRH (Kendall's tau b = 0.19; p<0.001). On univariate analysis, "completely satisfied" patients had a significantly lower risk of mortality (HR = 0.75; 95% CI: 0.57 to 0.99; p = 0.04). Similarly, patients with "excellent" SRH had a significantly lower risk of mortality (HR = 0.61; 95% CI: 0.46 to 0.81; p = 0.001). On multivariate analysis controlling for stage at diagnosis, treatment history and gender, SRH was found to be a significant predictor of survival (HR = 0.67; 95% CI: 0.50 to 0.89; p = 0.007) while PS was not (HR = 0.86; 95% CI: 0.64 to 1.2; p = 0.32). Among the individual PS items, the only significant independent predictor of survival was "teams communicating with each other

  13. A two-stage model in a Bayesian framework to estimate a survival endpoint in the presence of confounding by indication.

    Science.gov (United States)

    Bellera, Carine; Proust-Lima, Cécile; Joseph, Lawrence; Richaud, Pierre; Taylor, Jeremy; Sandler, Howard; Hanley, James; Mathoulin-Pélissier, Simone

    2018-04-01

    Background Biomarker series can indicate disease progression and predict clinical endpoints. When a treatment is prescribed depending on the biomarker, confounding by indication might be introduced if the treatment modifies the marker profile and risk of failure. Objective Our aim was to highlight the flexibility of a two-stage model fitted within a Bayesian Markov Chain Monte Carlo framework. For this purpose, we monitored the prostate-specific antigens in prostate cancer patients treated with external beam radiation therapy. In the presence of rising prostate-specific antigens after external beam radiation therapy, salvage hormone therapy can be prescribed to reduce both the prostate-specific antigens concentration and the risk of clinical failure, an illustration of confounding by indication. We focused on the assessment of the prognostic value of hormone therapy and prostate-specific antigens trajectory on the risk of failure. Methods We used a two-stage model within a Bayesian framework to assess the role of the prostate-specific antigens profile on clinical failure while accounting for a secondary treatment prescribed by indication. We modeled prostate-specific antigens using a hierarchical piecewise linear trajectory with a random changepoint. Residual prostate-specific antigens variability was expressed as a function of prostate-specific antigens concentration. Covariates in the survival model included hormone therapy, baseline characteristics, and individual predictions of the prostate-specific antigens nadir and timing and prostate-specific antigens slopes before and after the nadir as provided by the longitudinal process. Results We showed positive associations between an increased prostate-specific antigens nadir, an earlier changepoint and a steeper post-nadir slope with an increased risk of failure. Importantly, we highlighted a significant benefit of hormone therapy, an effect that was not observed when the prostate-specific antigens trajectory was

  14. Phosphate binder use and mortality among hemodialysis patients in the Dialysis Outcomes and Practice Patterns Study (DOPPS): evaluation of possible confounding by nutritional status.

    Science.gov (United States)

    Lopes, Antonio Alberto; Tong, Lin; Thumma, Jyothi; Li, Yun; Fuller, Douglas S; Morgenstern, Hal; Bommer, Jürgen; Kerr, Peter G; Tentori, Francesca; Akiba, Takashi; Gillespie, Brenda W; Robinson, Bruce M; Port, Friedrich K; Pisoni, Ronald L

    2012-07-01

    -sectional; dietary restriction was not assessed; observational design limits causal inference due to possible residual confounding. Longer survival and better nutritional status were observed for maintenance HD patients prescribed phosphate binders and in facilities with a greater percentage of phosphate binder prescription. Understanding the mechanisms for explaining this effect and ruling out possible residual confounding require additional research. Copyright © 2012 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

  15. Skeletal muscle connective tissue

    DEFF Research Database (Denmark)

    Brüggemann, Dagmar Adeline

    in the structure of fibrous collagen and myofibers at high-resolution. The results demonstrate that the collagen composition in the extra cellular matrix of Gadus morhua fish muscle is much more complex than previously anticipated, as it contains type III, IV, V  and VI collagen in addition to type I. The vascular....... Consequently, functional structures, ensuring "tissue maintenance" must form a major role of connective tissue, in addition that is to the force transmitting structures one typically finds in muscle. Vascular structures have also been shown to change their mechanical properties with age and it has been shown...

  16. A Web-based database for pathology faculty effort reporting.

    Science.gov (United States)

    Dee, Fred R; Haugen, Thomas H; Wynn, Philip A; Leaven, Timothy C; Kemp, John D; Cohen, Michael B

    2008-04-01

    To ensure appropriate mission-based budgeting and equitable distribution of funds for faculty salaries, our compensation committee developed a pathology-specific effort reporting database. Principles included the following: (1) measurement should be done by web-based databases; (2) most entry should be done by departmental administration or be relational to other databases; (3) data entry categories should be aligned with funding streams; and (4) units of effort should be equal across categories of effort (service, teaching, research). MySQL was used for all data transactions (http://dev.mysql.com/downloads), and scripts were constructed using PERL (http://www.perl.org). Data are accessed with forms that correspond to fields in the database. The committee's work resulted in a novel database using pathology value units (PVUs) as a standard quantitative measure of effort for activities in an academic pathology department. The most common calculation was to estimate the number of hours required for a specific task, divide by 2080 hours (a Medicare year) and then multiply by 100. Other methods included assigning a baseline PVU for program, laboratory, or course directorship with an increment for each student or staff in that unit. With these methods, a faculty member should acquire approximately 100 PVUs. Some outcomes include (1) plotting PVUs versus salary to identify outliers for salary correction, (2) quantifying effort in activities outside the department, (3) documenting salary expenditure for unfunded research, (4) evaluating salary equity by plotting PVUs versus salary by sex, and (5) aggregating data by category of effort for mission-based budgeting and long-term planning.

  17. Regularization in global sound equalization based on effort variation

    DEFF Research Database (Denmark)

    Stefanakis, Nick; Sarris, John; Jacobsen, Finn

    2009-01-01

    . Effort variation equalization involves modifying the conventional cost function in sound equalization, which is based on minimizing least-squares reproduction errors, by adding a term that is proportional to the squared deviations between complex source strengths, calculated independently for the sources......Sound equalization in closed spaces can be significantly improved by generating propagating waves that are naturally associated with the geometry, as, for example, plane waves in rectangular enclosures. This paper presents a control approach termed effort variation regularization based on this idea...

  18. An Alternative Method of Evaluating 1540NM Exposure Laser Damage using an Optical Tissue Phantom

    National Research Council Canada - National Science Library

    Jindra, Nichole M; Figueroa, Manuel A; Rockwell, Benjamin A; Chavey, Lucas J; Zohner, Justin J

    2006-01-01

    An optical phantom was designed to physically and optically resemble human tissue, in an effort to provide an alternative for detecting visual damage resulting from inadvertent exposure to infrared lasers...

  19. Tissue Sampling Guides for Porcine Biomedical Models.

    Science.gov (United States)

    Albl, Barbara; Haesner, Serena; Braun-Reichhart, Christina; Streckel, Elisabeth; Renner, Simone; Seeliger, Frank; Wolf, Eckhard; Wanke, Rüdiger; Blutke, Andreas

    2016-04-01

    This article provides guidelines for organ and tissue sampling adapted to porcine animal models in translational medical research. Detailed protocols for the determination of sampling locations and numbers as well as recommendations on the orientation, size, and trimming direction of samples from ∼50 different porcine organs and tissues are provided in the Supplementary Material. The proposed sampling protocols include the generation of samples suitable for subsequent qualitative and quantitative analyses, including cryohistology, paraffin, and plastic histology; immunohistochemistry;in situhybridization; electron microscopy; and quantitative stereology as well as molecular analyses of DNA, RNA, proteins, metabolites, and electrolytes. With regard to the planned extent of sampling efforts, time, and personnel expenses, and dependent upon the scheduled analyses, different protocols are provided. These protocols are adjusted for (I) routine screenings, as used in general toxicity studies or in analyses of gene expression patterns or histopathological organ alterations, (II) advanced analyses of single organs/tissues, and (III) large-scale sampling procedures to be applied in biobank projects. Providing a robust reference for studies of porcine models, the described protocols will ensure the efficiency of sampling, the systematic recovery of high-quality samples representing the entire organ or tissue as well as the intra-/interstudy comparability and reproducibility of results. © The Author(s) 2016.

  20. Failure in cartilaginous tissues

    NARCIS (Netherlands)

    Huyghe, J.M.R.J.; Talen-Jongeneelen, C.J.M.; Schroeder, Y.; Kraaijeveld, F.; Borst, de R.; Baaijens, F.P.T.

    2007-01-01

    Cartilaginous tissues high load bearing capacity is explained by osmotic prestressing putting the collagen fiber reinforcement under tension and the proteoglycan gel under compression. The osmotic forces are boosted by a further 50 % by the affinity of the collagen with the aquous solution. The high

  1. Connective tissue activation. XVII

    International Nuclear Information System (INIS)

    Weiss, J.J.; Donakowski, C.; Anderson, B.; Meyers, S.; Castor, C.W.

    1980-01-01

    The platelet-derived connective tissue activating peptide (CTAP-III) has been shown to be an important factor stimulating the metabolism and proliferation of human connective tissue cell strains, including synovial tissue cells. The quantities of CTAP-III affecting the cellular changes and the amounts in various biologic fluids and tissues are small. The objectives of this study were to develop a radioimmunoassay (RIA) for CTAP-III and to ascertain the specificities of the anti-CTAP-III sera reagents. The antisera were shown not to cross-react with a number of polypeptide hormones. However, two other platelet proteins β-thromboglobulin and low affinity platelet factor-4, competed equally as well as CTAP-III for anti-CTAP-III antibodies in the RIA system. Thus, the three platelet proteins are similar or identical with respect to those portions of the molecules constituting the reactive antigenic determinants. The levels of material in normal human platelet-free plasma that inhibited anti-CTAP-III- 125 I-CTAP-III complex formation were determined to be 34+-13 (S.D.) ng/ml. (Auth.)

  2. Soft Tissue Extramedullary Plasmacytoma

    Directory of Open Access Journals (Sweden)

    Fernando Ruiz Santiago

    2010-01-01

    Full Text Available We present the uncommon case of a subcutaneous fascia-based extramedullary plasmacytoma in the leg, which was confirmed by the pathology report and followed up until its remission. We report the differential diagnosis with other more common soft tissue masses. Imaging findings are nonspecific but are important to determine the tumour extension and to plan the biopsy.

  3. Neoproteoglycans in tissue engineering

    Science.gov (United States)

    Weyers, Amanda; Linhardt, Robert J.

    2014-01-01

    Proteoglycans, comprised of a core protein to which glycosaminoglycan chains are covalently linked, are an important structural and functional family of macromolecules found in the extracellular matrix. Advances in our understanding of biological interactions have lead to a greater appreciation for the need to design tissue engineering scaffolds that incorporate mimetics of key extracellular matrix components. A variety of synthetic and semisynthetic molecules and polymers have been examined by tissue engineers that serve as structural, chemical and biological replacements for proteoglycans. These proteoglycan mimetics have been referred to as neoproteoglycans and serve as functional and therapeutic replacements for natural proteoglycans that are often unavailable for tissue engineering studies. Although neoproteoglycans have important limitations, such as limited signaling ability and biocompatibility, they have shown promise in replacing the natural activity of proteoglycans through cell and protein binding interactions. This review focuses on the recent in vivo and in vitro tissue engineering applications of three basic types of neoproteoglycan structures, protein–glycosaminoglycan conjugates, nano-glycosaminoglycan composites and polymer–glycosaminoglycan complexes. PMID:23399318

  4. Sensing in tissue bioreactors

    Science.gov (United States)

    Rolfe, P.

    2006-03-01

    Specialized sensing and measurement instruments are under development to aid the controlled culture of cells in bioreactors for the fabrication of biological tissues. Precisely defined physical and chemical conditions are needed for the correct culture of the many cell-tissue types now being studied, including chondrocytes (cartilage), vascular endothelial cells and smooth muscle cells (blood vessels), fibroblasts, hepatocytes (liver) and receptor neurones. Cell and tissue culture processes are dynamic and therefore, optimal control requires monitoring of the key process variables. Chemical and physical sensing is approached in this paper with the aim of enabling automatic optimal control, based on classical cell growth models, to be achieved. Non-invasive sensing is performed via the bioreactor wall, invasive sensing with probes placed inside the cell culture chamber and indirect monitoring using analysis within a shunt or a sampling chamber. Electroanalytical and photonics-based systems are described. Chemical sensing for gases, ions, metabolites, certain hormones and proteins, is under development. Spectroscopic analysis of the culture medium is used for measurement of glucose and for proteins that are markers of cell biosynthetic behaviour. Optical interrogation of cells and tissues is also investigated for structural analysis based on scatter.

  5. Management of a Septic Open Abdomen Patient with Spontaneous Jejunal Perforation after Emergent C/S with Confounding Factor of Mild Acute Pancreatitis.

    Science.gov (United States)

    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.

  6. The effect of polytrauma as a possible confounder in the outcome of monotraumatic vs polytraumatic paraplegic patients: a clinical cohort study.

    Science.gov (United States)

    Putz, C; Schuld, C; Gantz, S; Grieser, T; Akbar, M; Moradi, B; Wiedenhöfer, B; Fürstenberg, C H; Gerner, H J; Rupp, R

    2011-06-01

    Clinical cohort study. To evaluate if the impact of the severity of the trauma as a possible confounding factor influences the neurological and functional recovery in paraplegia during the course of a 6-month follow-up period after injury. Spinal Cord Injury Center, Heidelberg University Hospital, Germany. A retrospective monocentric analysis, from 2002 to 2008, of the Heidelberg European Multicenter Study about spinal cord injury database was performed. We included 31 paraplegic patients (neurological level T1-T12) who were assigned either to a monotrauma (polytraumaschluessel (PTS) 1) or to a polytrauma (PTS≥2) group. The American Spinal Injury Association Impairment Scale, lower extremity motor score, pin prick, light touch and the spinal cord independence measure (SCIM) were obtained at five distinct time points after trauma. Data were analyzed using Mann-Whitney U-test (αpressure sores between 3 and 6 months (P=0.031). The mean length of primary rehabilitation in the polytrauma group was 5.5 vs 3.6 months in monotrauma. The prognosis of polytraumatic paraplegics in terms of neurological recovery is not inferior to those with monotrauma. Multiple-injured patients need a prolonged hospital stay to reach the functional outcome of monotraumatic patients.

  7. Sequence variation does not confound the measurement of plasma PfHRP2 concentration in African children presenting with severe malaria

    Directory of Open Access Journals (Sweden)

    Ramutton Thiranut

    2012-08-01

    Full Text Available Abstract Background Plasmodium falciparum histidine-rich protein PFHRP2 measurement is used widely for diagnosis, and more recently for severity assessment in falciparum malaria. The Pfhrp2 gene is highly polymorphic, with deletion of the entire gene reported in both laboratory and field isolates. These issues potentially confound the interpretation of PFHRP2 measurements. Methods Studies designed to detect deletion of Pfhrp2 and its paralog Pfhrp3 were undertaken with samples from patients in seven countries contributing to the largest hospital-based severe malaria trial (AQUAMAT. The quantitative relationship between sequence polymorphism and PFHRP2 plasma concentration was examined in samples from selected sites in Mozambique and Tanzania. Results There was no evidence for deletion of either Pfhrp2 or Pfhrp3 in the 77 samples with lowest PFHRP2 plasma concentrations across the seven countries. Pfhrp2 sequence diversity was very high with no haplotypes shared among 66 samples sequenced. There was no correlation between Pfhrp2 sequence length or repeat type and PFHRP2 plasma concentration. Conclusions These findings indicate that sequence polymorphism is not a significant cause of variation in PFHRP2 concentration in plasma samples from African children. This justifies the further development of plasma PFHRP2 concentration as a method for assessing African children who may have severe falciparum malaria. The data also add to the existing evidence base supporting the use of rapid diagnostic tests based on PFHRP2 detection.

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

    International Nuclear Information System (INIS)

    Beketov, Mikhail A.; Liess, Matthias

    2008-01-01

    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. - Indicator for organic toxicants at community level can be independent of natural environmental factors

  9. Management of a Septic Open Abdomen Patient with Spontaneous Jejunal Perforation after Emergent C/S with Confounding Factor of Mild Acute Pancreatitis

    Directory of Open Access Journals (Sweden)

    Fahri Yetisir

    2016-01-01

    Full Text Available 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.

  10. [Biofabrication: new approaches for tissue regeneration].

    Science.gov (United States)

    Horch, Raymund E; Weigand, Annika; Wajant, Harald; Groll, Jürgen; Boccaccini, Aldo R; Arkudas, Andreas

    2018-04-01

    The advent of Tissue Engineering (TE) in the early 1990ies was fostered by the increasing need for functional tissue and organ replacement. Classical TE was based on the combination of carrier matrices, cells and growth factors to reconstitute lost or damaged tissue and organs. Despite considerable results in vitro and in experimental settings the lack of early vascularization has hampered its translation into daily clinical practice so far. A new field of research, called "biofabrication" utilizing latest 3D printing technologies aims at hierarchically and spatially incorporating different cells, biomaterials and molecules into a matrix to alleviate a directed maturation of artificial tissue. A literature research of the relevant publications regarding biofabrication and bioprinting was performed using the PubMed data base. Relevant papers were selected and evaluated with secondary analysis of specific citations on the bioprinting techniques. 180 relevant papers containing the key words were identified and evaluated. Basic principles into the developing field of bioprinting technology could be discerned. Key elements comprise the high-throughput assembly of cells and the fabrication of complex and functional hierarchically organized tissue constructs. Five relevant technological principles for bioprinting were identified, such as stereolithography, extrusion-based printing, laser-assisted printing, inkjet-based printing and nano-bioprinting. The different technical methods of 3D printing were found to be associated with various positive but also negative effects on cells and proteins during the printing process. Research efforts in this field obviously aim towards the development of optimizing the so called bioinks and the printing technologies. This review details the evolution of the classical methods of TE in Regenerative Medicine into the evolving field of biofabrication by bioprinting. The advantages of 3D bioprinting over traditional tissue engineering

  11. Survey of public knowledge in tissue banking in Malaysia

    International Nuclear Information System (INIS)

    Norimah Yusof; Asnah Hassan

    1998-01-01

    A survey was conducted with the objective to determine the level of public knowledge and awareness in tissue banking. From 233 respondents of 62.2% male and 37.8% female, only 44.6% have heard about tissue banking in Malaysia, mainly from newspapers and mass media, and only 11.6% realised the existence of the two tissue banks i.e at MINT, Bangi and USM, Kubang Kerian. However, higher percentage of respondents were aware of donation for both organs (56.2%) and tissues (51.1%). When asked about donating, 54.5% were willing to donate after death and surprisingly only 39.9% as life donors. On the contrary, 71.7% were willing to accept tissue grafts for clinical treatment and transplantation. The findings suggest that more aggressive publicity on tissue banking is necessary and more detailed information have to be made known especially regarding the 'fatwa' in particular for the Muslims and the Human Tissue Act 1974 for the general public. This may lead to even better response to the tissue donation programme which is being planned. Most of the respondents congratulated both tissue banks in our effort to develop indigenous expertise in this interesting new venture with high appreciation to our social and welfare obligations

  12. Nanotopography-guided tissue engineering and regenerative medicine☆

    Science.gov (United States)

    Kim, Hong Nam; Jiao, Alex; Hwang, Nathaniel S.; Kim, Min Sung; Kang, Do Hyun; Kim, Deok-Ho; Suh, Kahp-Yang

    2017-01-01

    Human tissues are intricate ensembles of multiple cell types embedded in complex and well-defined structures of the extracellular matrix (ECM). The organization of ECM is frequently hierarchical from nano to macro, with many proteins forming large scale structures with feature sizes up to several hundred microns. Inspired from these natural designs of ECM, nanotopography-guided approaches have been increasingly investigated for the last several decades. Results demonstrate that the nanotopography itself can activate tissue-specific function in vitro as well as promote tissue regeneration in vivo upon transplantation. In this review, we provide an extensive analysis of recent efforts to mimic functional nanostructures in vitro for improved tissue engineering and regeneration of injured and damaged tissues. We first characterize the role of various nanostructures in human tissues with respect to each tissue-specific function. Then, we describe various fabrication methods in terms of patterning principles and material characteristics. Finally, we summarize the applications of nanotopography to various tissues, which are classified into four types depending on their functions: protective, mechano-sensitive, electro-active, and shear stress-sensitive tissues. Some limitations and future challenges are briefly discussed at the end. PMID:22921841

  13. Tissue engineering and surgery: from translational studies to human trials

    Directory of Open Access Journals (Sweden)

    Vranckx Jan Jeroen

    2017-06-01

    Full Text Available Tissue engineering was introduced as an innovative and promising field in the mid-1980s. The capacity of cells to migrate and proliferate in growth-inducing medium induced great expectancies on generating custom-shaped bioconstructs for tissue regeneration. Tissue engineering represents a unique multidisciplinary translational forum where the principles of biomaterial engineering, the molecular biology of cells and genes, and the clinical sciences of reconstruction would interact intensively through the combined efforts of scientists, engineers, and clinicians. The anticipated possibilities of cell engineering, matrix development, and growth factor therapies are extensive and would largely expand our clinical reconstructive armamentarium. Application of proangiogenic proteins may stimulate wound repair, restore avascular wound beds, or reverse hypoxia in flaps. Autologous cells procured from biopsies may generate an ‘autologous’ dermal and epidermal laminated cover on extensive burn wounds. Three-dimensional printing may generate ‘custom-made’ preshaped scaffolds – shaped as a nose, an ear, or a mandible – in which these cells can be seeded. The paucity of optimal donor tissues may be solved with off-the-shelf tissues using tissue engineering strategies. However, despite the expectations, the speed of translation of in vitro tissue engineering sciences into clinical reality is very slow due to the intrinsic complexity of human tissues. This review focuses on the transition from translational protocols towards current clinical applications of tissue engineering strategies in surgery.

  14. Bone tissue engineering scaffolding: computer-aided scaffolding techniques.

    Science.gov (United States)

    Thavornyutikarn, Boonlom; Chantarapanich, Nattapon; Sitthiseripratip, Kriskrai; Thouas, George A; Chen, Qizhi

    Tissue engineering is essentially a technique for imitating nature. Natural tissues consist of three components: cells, signalling systems (e.g. growth factors) and extracellular matrix (ECM). The ECM forms a scaffold for its cells. Hence, the engineered tissue construct is an artificial scaffold populated with living cells and signalling molecules. A huge effort has been invested in bone tissue engineering, in which a highly porous scaffold plays a critical role in guiding bone and vascular tissue growth and regeneration in three dimensions. In the last two decades, numerous scaffolding techniques have been developed to fabricate highly interconnective, porous scaffolds for bone tissue engineering applications. This review provides an update on the progress of foaming technology of biomaterials, with a special attention being focused on computer-aided manufacturing (Andrade et al. 2002) techniques. This article starts with a brief introduction of tissue engineering (Bone tissue engineering and scaffolds) and scaffolding materials (Biomaterials used in bone tissue engineering). After a brief reviews on conventional scaffolding techniques (Conventional scaffolding techniques), a number of CAM techniques are reviewed in great detail. For each technique, the structure and mechanical integrity of fabricated scaffolds are discussed in detail. Finally, the advantaged and disadvantage of these techniques are compared (Comparison of scaffolding techniques) and summarised (Summary).

  15. The Interaction between Negative Emotionality and Effortful Control in Early

    Science.gov (United States)

    Moran, Lyndsey R.; Lengua, Liliana J.; Zalewski, Maureen

    2013-01-01

    Interactions between reactive and regulatory dimensions of temperament may be particularly relevant to children's adjustment but are examined infrequently. This study investigated these interactions by examining effortful control as a moderator of the relations of fear and frustration reactivity to children's social competence, internalizing, and…

  16. Changing reproductive effort within a semelparous reproductive episode.

    Science.gov (United States)

    Hughes, P William; Simons, Andrew M

    2014-08-01

    • Life-history theory predicts a trade-off between current and future reproduction for iteroparous organisms-as individuals age, the expected value of future reproduction declines, and thus reproductive effort is expected to be higher in later clutches than in earlier. In contrast, models explaining the evolution of semelparity treat semelparous reproduction as instantaneous, with no scope for intraindividual variation. However, semelparous reproduction is also extended, but over shorter time scales; whether there are similar age- or stage-specific changes in reproductive effort within a semelparous episode is unclear. In this study, we assessed whether semelparous individuals increase reproductive effort as residual reproductive value declines by comparing the reproductive phenotype of flowers at five different floral positions along a main inflorescence.• Using the herbaceous monocarp Lobelia inflata, we conducted a longitudinal study of 409 individuals including both laboratory and field populations over three seasons. We recorded six reproductive traits-including the length of three phenological intervals as well as fruit size, seed size, and seed number-for all plants across floral positions produced throughout the reproductive episode.• We found that while the rate of flower initiation did not change, flowers at distal (late) floral positions developed more quickly and contained larger seed than flowers at basal (early) floral positions did.• Our results were consistent with the hypothesis that, like iteroparous organisms, L. inflata increases reproductive effort in response to low residual reproductive value. © 2014 Botanical Society of America, Inc.

  17. Economic response to harvest and effort control in fishery

    DEFF Research Database (Denmark)

    Hoff, Ayoe; Frost, Hans

    for fisheries management. The report outlines bio-economic models, which are designed to shed light on the efficiency of different management tools in terms of quota or effort restrictions given the objectives of the Common Fisheries Policy about sustainable and economic viable fisheries. The report addresses...... the complexities of biological and economic interaction in a multispecies, multifleet framework and outlines consistent mathematical models....

  18. Do Haphazard Reviews Provide Sound Directions for Dissemination Efforts?

    Science.gov (United States)

    Gambrill, Eileen; Littell, Julia H.

    2010-01-01

    Comments on The dissemination and implementation of evidence-based psychological treatments: A review of current efforts by Kathryn R. McHugh and David H. Barlow. The lead article in the February-March issue by McHugh and Barlow (2010) emphasized the need for "dissemination and implementation of evidence-based psychological treatments."…

  19. Separate valuation subsystems for delay and effort decision costs.

    Science.gov (United States)

    Prévost, Charlotte; Pessiglione, Mathias; Météreau, Elise; Cléry-Melin, Marie-Laure; Dreher, Jean-Claude

    2010-10-20

    Decision making consists of choosing among available options on the basis of a valuation of their potential costs and benefits. Most theoretical models of decision making in behavioral economics, psychology, and computer science propose that the desirability of outcomes expected from alternative options can be quantified by utility functions. These utility functions allow a decision maker to assign subjective values to each option under consideration by weighting the likely benefits and costs resulting from an action and to select the one with the highest subjective value. Here, we used model-based neuroimaging to test whether the human brain uses separate valuation systems for rewards (erotic stimuli) associated with different types of costs, namely, delay and effort. We show that humans devalue rewards associated with physical effort in a strikingly similar fashion to those they devalue that are associated with delays, and that a single computational model derived from economics theory can account for the behavior observed in both delay discounting and effort discounting. However, our neuroimaging data reveal that the human brain uses distinct valuation subsystems for different types of costs, reflecting in opposite fashion delayed reward and future energetic expenses. The ventral striatum and the ventromedial prefrontal cortex represent the increasing subjective value of delayed rewards, whereas a distinct network, composed of the anterior cingulate cortex and the anterior insula, represent the decreasing value of the effortful option, coding the expected expense of energy. Together, these data demonstrate that the valuation processes underlying different types of costs can be fractionated at the cerebral level.

  20. The public service-motivated volunteer devoting time or effort

    DEFF Research Database (Denmark)

    Costello, Joyce; Homberg, Fabian; Secchi, Davide

    2017-01-01

    and thus may inform subsequent empirical work. First, we address academic debates concerning the measurement of volunteer effort. Second, we propose using public service motivation (PSM) theory as a means to understand the motivation of volunteers across sectors. We suggest that different PSM dimensions...

  1. Anti-Money Laundering Efforts - Failures, Fixes and the Future

    NARCIS (Netherlands)

    Deleanu, I.S.

    2015-01-01

    In this PhD thesis I address important topics in the debate on and the organisation of the Anti-Money Laundering efforts, which are related to the legitimacy and the effectiveness of the Anti-Money Laundering policies. First of all, this thesis provides a reflection on the assessments of concern

  2. Shopping Effort Classification: Implications for Segmenting the College Student Market

    Science.gov (United States)

    Wright, Robert E.; Palmer, John C.; Eidson, Vicky; Griswold, Melissa

    2011-01-01

    Market segmentation strategies based on levels of consumer shopping effort have long been utilized by marketing professionals. Such strategies can be beneficial in assisting marketers with development of appropriate marketing mix variables for segments. However, these types of strategies have not been assessed by researchers examining segmentation…

  3. Variation in working effort in Danish Little Owls Athene noctua

    DEFF Research Database (Denmark)

    Holsegård-Rasmussen, Miriam H.; Sunde, Peter; Thorup, K.

    2009-01-01

    with extinction. The study is based on 143 one-hour surveys of breeding and 274 surveys of non-breeding Little Owls (27 territorial individuals on 14 territories). Working effort is calculated as the total linear distance between all observed consecutive telemetry fixes during one-hour surveys (Minimum Flight...

  4. NASA OSMA NDE Program Additive Manufacturing Foundational Effort

    Science.gov (United States)

    Waller, Jess; Walker, James; Burke, Eric; Wells, Douglas; Nichols, Charles

    2016-01-01

    NASA is providing key leadership in an international effort linking NASA and non-NASA resources to speed adoption of additive manufacturing (AM) to meet NASA's mission goals. Participants include industry, NASA's space partners, other government agencies, standards organizations and academia. Nondestructive Evaluation (NDE) is identified as a universal need for all aspects of additive manufacturing.

  5. Integration test effort in SAP R/3 systems

    NARCIS (Netherlands)

    Griend, van de P.A.; Kusters, R.J.

    2012-01-01

    This paper describes an experimental approach towards the definition of a metric for integration test effort based on enterprise resource planning (ERP) system logs. By nature, ERP systems are complex. After implementing an ERP-system, it is typically subjected to many, and often concurrent,

  6. A Real-Effort Experiment on Gift Exchange with Temptation

    DEFF Research Database (Denmark)

    Koch, Alexander Karl; Nafziger, Julia

    We conduct a real-effort experiment to test whether workers reciprocate generous wages by managers when workers are tempted to surf the internet. Further, we investigate how an active policy of restricting the usage of the internet affects the workers' motivation. We observe that the temptation o...

  7. City Logistics Modeling Efforts : Trends and Gaps - A Review

    NARCIS (Netherlands)

    Anand, N.R.; Quak, H.J.; Van Duin, J.H.R.; Tavasszy, L.A.

    2012-01-01

    In this paper, we present a review of city logistics modeling efforts reported in the literature for urban freight analysis. The review framework takes into account the diversity and complexity found in the present-day city logistics practice. Next, it covers the different aspects in the modeling

  8. Principal efforts in improving the understanding of Climate impact of ...

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Principal efforts in improving the understanding of Climate impact of aerosols -. New and enhanced satellite borne sensors. Focused field experiments. Establishment and enhancement of ground based networks. Development and deployment of new and enhanced ...

  9. Implementation of Pre-Operative Checklist: An Effort to Reduce ...

    African Journals Online (AJOL)

    Implementation of Pre-Operative Checklist: An Effort to Reduce Delays in. Surgery and ... insight to develop a pre-operative checklist to ensure that patients were prepared for surgery and to minimize disruptions ... documentation audit was conducted in May 2014, showing 59% compliance in completing the checklist. Since.

  10. Efforts towards the development of recombinant Vaccines against ...

    African Journals Online (AJOL)

    Hemorrhagic septicemia is caused by gram-negative bacterium of Pasteurella multocida (P. multocida) strains. Most of the current vaccines against P. multocida have shortcomings. Presently, there is increasing efforts towards construction of recombinant clone for vaccine development against P. multocida. In this review an ...

  11. Efforts Towards The Development Of Recombinant Vaccines Against

    African Journals Online (AJOL)

    ABSTRACT. Hemorrhagic septicemia is caused by gram-negative bacterium of Pasteurella multocida (P. multocida) strains. Most of the current vaccines against P. multocida have shortcomings. Presently, there is increasing efforts towards construction of recombinant clone for vaccine development against P. multocida.

  12. Green Roof Research through EPA's Regional Applied Research Effort - slides

    Science.gov (United States)

    The U.S. Environmental Protection Agency’s (EPA) Regional Applied Research Effort (RARE) allows the Regions of the EPA to choose research projects to be performed in partnership with EPA’s Office of Research and Development (ORD). Over the last decade, several green roof projects...

  13. Green Roof Research through EPA's Regional Applied Research Effort

    Science.gov (United States)

    ABSTRACT The U.S. Environmental Protection Agency’s (EPA) Regional Applied Research Effort (RARE) allows the Regions of the EPA to choose research projects to be performed in partnership with EPA’s Office of Research and Development (ORD). Over the last decade, several green roo...

  14. The Index of Asia-Pacific Regional Integration Effort

    Directory of Open Access Journals (Sweden)

    Victor Yifan Ye

    2016-06-01

    Full Text Available The Asia-Pacific region is not typically seen as one geographic or socio-economic space. Yet, 58 regional economies occupying the space of 28 million square kilometers from Turkey in the West, Russian Federation in the North, French Polynesia in the East and New Zealand in the South belong to the Economic and Social Commission of Asia and the Pacific (ESCAP. This commission provides a forum for member states that "promotes regional cooperation and collective action, assisting countries in building and sustaining shared economic growth and social equity". In 2013, ESCAP's members adopted the Bangkok Declaration to enhance efforts towards deeper regional economic integration. Yet this document neither proposes a concrete modality or modalities of achieving deeper integration, nor provides a sense of distance of individual countries to a "perceived" integrated Asia-Pacific.This paper aims to comprehensively quantify recent integration efforts of economies in the Asia-Pacific region. We provide an "index of integration effort" based on twelve metrics that measure the relative distance of a given economy to the region as an economic entity. Generally, we find that while the region has trended towards becoming integrated in general, both the level of integration and integration effort are inconsistent among Asia-Pacific economies. We discuss potential applications and extensions of the index in developing our perspective of the region's economic and social dynamics.

  15. Anticipated emotions and effort allocation in weight goal striving

    NARCIS (Netherlands)

    Nelissen, R.M.A.; de Vet, H.C.W.; Zeelenberg, M.

    2011-01-01

    Objective. This study aimed to investigate the influence of anticipated emotions on preventive health behaviour if specified at the level of behavioural outcomes. Consistent with predictions from a recently developed model of goal pursuit, we hypothesized that the impact of emotions on effort levels

  16. School Climate and Leadership: Levers for School Improvement Efforts

    Science.gov (United States)

    Costa, Lois

    2016-01-01

    This qualitative study considers which aspects of school climate support or inhibit student achievement as each aspect relates to school leadership and school reform efforts. Due to the increased responsibility and accountability which schools face during these challenging times, school climate and the role of the school principal formed the basis…

  17. Assessing the Army Power and Energy Efforts for the Warfighter

    Science.gov (United States)

    2011-03-01

    term. Details are in Appendix B. The report places energy challenges in three categories: greatest use, greatest difficulty, and greatest impact ...Power and energy testing Silicon carbide Two new energy facilities New types of solar photovoltaic systems Smaller, lighter cogeneration and...Assessing the Army Power and Energy Efforts for the Warfighter John W. Lyons, Richard Chait, and James J. Valdes

  18. Survey of European Community efforts in RF heating

    International Nuclear Information System (INIS)

    Consoli, T.

    1981-01-01

    The present paper briefly reviews the efforts made over the last 10 years, with particular emphasis on the period from 1978 to 1980. The RF heating experiments within EC are presented: low frequency heating; heating at medium frequencies (ICRH); RF heating at low hybrid frequency; heating at the ECR frequency. The plan of Tore-Supra is given

  19. Current research efforts of EP study in Korea

    International Nuclear Information System (INIS)

    Ryu, C.M.

    2013-01-01

    After the successful demonstration of H mode on KSTAR, the problem of fast-ion driven MHD modes such as Alfven eigenmodes (AEs) and the reverse effects on fast ions of MHD modes is under study in KSTAR. In this paper, I will briefly describe some recent efforts of KSTAR on energetic particle physics study. (J.P.N.)

  20. The Vatican and Unesco Link Efforts for World Literacy

    Science.gov (United States)

    Ryan, Leo V., Brother

    1970-01-01

    The problem of functional literacy has been recognized as a moral issue and offers a special challenge to religious authorities. Founded at the Vatican level in March 1969, the Committee on Human Development was commissioned to promote and animate efforts in: (a) basic education; (b) leadership training; (c) vocational education; (d) opinion…