Transnasal endoscopic evaluation of swallowing: a bedside technique to evaluate ability to swallow pureed diets in elderly patients with dysphagia.

PubMed

Sakamoto, Torao; Horiuchi, Akira; Nakayama, Yoshiko

2013-08-01

Endoscopic evaluation of swallowing (EES) is not commonly used by gastroenterologists to evaluate swallowing in patients with dysphagia. To use transnasal endoscopy to identify factors predicting successful or failed swallowing of pureed foods in elderly patients with dysphagia. EES of pureed foods was performed by a gastroenterologist using a small-calibre transnasal endoscope. Factors related to successful versus unsuccessful swallowing of pureed foods were analyzed with regard to age, comorbid diseases, swallowing activity, saliva pooling, vallecular residues, pharyngeal residues and airway penetration⁄aspiration. Unsuccessful swallowing was defined in patients who could not eat pureed foods at bedside during hospitalization. Logistic regression analysis was used to identify independent predictors of swallowing of pureed foods. During a six-year period, 458 consecutive patients (mean age 80 years [range 39 to 97 years]) were considered for the study, including 285 (62%) men. Saliva pooling, vallecular residues, pharyngeal residues and penetration⁄aspiration were found in 240 (52%), 73 (16%), 226 (49%) and 232 patients (51%), respectively. Overall, 247 patients (54%) failed to swallow pureed foods. Multivariate logistic regression analysis demonstrated that the presence of pharyngeal residues (OR 6.0) and saliva pooling (OR 4.6) occurred significantly more frequently in patients who failed to swallow pureed foods. Pharyngeal residues and saliva pooling predicted impaired swallowing of pureed foods. Transnasal EES performed by a gastroenterologist provided a unique bedside method of assessing the ability to swallow pureed foods in elderly patients with dysphagia.

A diagnostic analysis of the VVP single-doppler retrieval technique

NASA Technical Reports Server (NTRS)

Boccippio, Dennis J.

1995-01-01

A diagnostic analysis of the VVP (volume velocity processing) retrieval method is presented, with emphasis on understanding the technique as a linear, multivariate regression. Similarities and differences to the velocity-azimuth display and extended velocity-azimuth display retrieval techniques are discussed, using this framework. Conventional regression diagnostics are then employed to quantitatively determine situations in which the VVP technique is likely to fail. An algorithm for preparation and analysis of a robust VVP retrieval is developed and applied to synthetic and actual datasets with high temporal and spatial resolution. A fundamental (but quantifiable) limitation to some forms of VVP analysis is inadequate sampling dispersion in the n space of the multivariate regression, manifest as a collinearity between the basis functions of some fitted parameters. Such collinearity may be present either in the definition of these basis functions or in their realization in a given sampling configuration. This nonorthogonality may cause numerical instability, variance inflation (decrease in robustness), and increased sensitivity to bias from neglected wind components. It is shown that these effects prevent the application of VVP to small azimuthal sectors of data. The behavior of the VVP regression is further diagnosed over a wide range of sampling constraints, and reasonable sector limits are established.

Fuzzy multinomial logistic regression analysis: A multi-objective programming approach

NASA Astrophysics Data System (ADS)

Abdalla, Hesham A.; El-Sayed, Amany A.; Hamed, Ramadan

2017-05-01

Parameter estimation for multinomial logistic regression is usually based on maximizing the likelihood function. For large well-balanced datasets, Maximum Likelihood (ML) estimation is a satisfactory approach. Unfortunately, ML can fail completely or at least produce poor results in terms of estimated probabilities and confidence intervals of parameters, specially for small datasets. In this study, a new approach based on fuzzy concepts is proposed to estimate parameters of the multinomial logistic regression. The study assumes that the parameters of multinomial logistic regression are fuzzy. Based on the extension principle stated by Zadeh and Bárdossy's proposition, a multi-objective programming approach is suggested to estimate these fuzzy parameters. A simulation study is used to evaluate the performance of the new approach versus Maximum likelihood (ML) approach. Results show that the new proposed model outperforms ML in cases of small datasets.

Assessing the Multidimensional Relationship Between Medication Beliefs and Adherence in Older Adults With Hypertension Using Polynomial Regression.

PubMed

Dillon, Paul; Phillips, L Alison; Gallagher, Paul; Smith, Susan M; Stewart, Derek; Cousins, Gráinne

2018-02-05

The Necessity-Concerns Framework (NCF) is a multidimensional theory describing the relationship between patients' positive and negative evaluations of their medication which interplay to influence adherence. Most studies evaluating the NCF have failed to account for the multidimensional nature of the theory, placing the separate dimensions of medication "necessity beliefs" and "concerns" onto a single dimension (e.g., the Beliefs about Medicines Questionnaire-difference score model). To assess the multidimensional effect of patient medication beliefs (concerns and necessity beliefs) on medication adherence using polynomial regression with response surface analysis. Community-dwelling older adults >65 years (n = 1,211) presenting their own prescription for antihypertensive medication to 106 community pharmacies in the Republic of Ireland rated their concerns and necessity beliefs to antihypertensive medications at baseline and their adherence to antihypertensive medication at 12 months via structured telephone interview. Confirmatory polynomial regression found the difference-score model to be inaccurate; subsequent exploratory analysis identified a quadratic model to be the best-fitting polynomial model. Adherence was lowest among those with strong medication concerns and weak necessity beliefs, and adherence was greatest for those with weak concerns and strong necessity beliefs (slope β = -0.77, p<.001; curvature β = -0.26, p = .004). However, novel nonreciprocal effects were also observed; patients with simultaneously high concerns and necessity beliefs had lower adherence than those with simultaneously low concerns and necessity beliefs (slope β = -0.36, p = .004; curvature β = -0.25, p = .003). The difference-score model fails to account for the potential nonreciprocal effects. Results extend evidence supporting the use of polynomial regression to assess the multidimensional effect of medication beliefs on adherence.

Resitting or Compensating a Failed Examination: Does It Affect Subsequent Results?

ERIC Educational Resources Information Center

Arnold, Ivo

2017-01-01

Institutions of higher education commonly employ a conjunctive standard setting strategy, which requires students to resit failed examinations until they pass all tests. An alternative strategy allows students to compensate a failing grade with other test results. This paper uses regression discontinuity design to compare the effect of first-year…

Transnasal endoscopic evaluation of swallowing: A bedside technique to evaluate ability to swallow pureed diets in elderly patients with dysphagia

PubMed Central

Sakamoto, Torao; Horiuchi, Akira; Nakayama, Yoshiko

2013-01-01

BACKGROUND: Endoscopic evaluation of swallowing (EES) is not commonly used by gastroenterologists to evaluate swallowing in patients with dysphagia. OBJECTIVE: To use transnasal endoscopy to identify factors predicting successful or failed swallowing of pureed foods in elderly patients with dysphagia. METHODS: EES of pureed foods was performed by a gastroenterologist using a small-calibre transnasal endoscope. Factors related to successful versus unsuccessful swallowing of pureed foods were analyzed with regard to age, comorbid diseases, swallowing activity, saliva pooling, vallecular residues, pharyngeal residues and airway penetration/aspiration. Unsuccessful swallowing was defined in patients who could not eat pureed foods at bedside during hospitalization. Logistic regression analysis was used to identify independent predictors of swallowing of pureed foods. RESULTS: During a six-year period, 458 consecutive patients (mean age 80 years [range 39 to 97 years]) were considered for the study, including 285 (62%) men. Saliva pooling, vallecular residues, pharyngeal residues and penetration/aspiration were found in 240 (52%), 73 (16%), 226 (49%) and 232 patients (51%), respectively. Overall, 247 patients (54%) failed to swallow pureed foods. Multivariate logistic regression analysis demonstrated that the presence of pharyngeal residues (OR 6.0) and saliva pooling (OR 4.6) occurred significantly more frequently in patients who failed to swallow pureed foods. CONCLUSIONS: Pharyngeal residues and saliva pooling predicted impaired swallowing of pureed foods. Transnasal EES performed by a gastroenterologist provided a unique bedside method of assessing the ability to swallow pureed foods in elderly patients with dysphagia. PMID:23936875

A Bayesian goodness of fit test and semiparametric generalization of logistic regression with measurement data.

PubMed

Schörgendorfer, Angela; Branscum, Adam J; Hanson, Timothy E

2013-06-01

Logistic regression is a popular tool for risk analysis in medical and population health science. With continuous response data, it is common to create a dichotomous outcome for logistic regression analysis by specifying a threshold for positivity. Fitting a linear regression to the nondichotomized response variable assuming a logistic sampling model for the data has been empirically shown to yield more efficient estimates of odds ratios than ordinary logistic regression of the dichotomized endpoint. We illustrate that risk inference is not robust to departures from the parametric logistic distribution. Moreover, the model assumption of proportional odds is generally not satisfied when the condition of a logistic distribution for the data is violated, leading to biased inference from a parametric logistic analysis. We develop novel Bayesian semiparametric methodology for testing goodness of fit of parametric logistic regression with continuous measurement data. The testing procedures hold for any cutoff threshold and our approach simultaneously provides the ability to perform semiparametric risk estimation. Bayes factors are calculated using the Savage-Dickey ratio for testing the null hypothesis of logistic regression versus a semiparametric generalization. We propose a fully Bayesian and a computationally efficient empirical Bayesian approach to testing, and we present methods for semiparametric estimation of risks, relative risks, and odds ratios when parametric logistic regression fails. Theoretical results establish the consistency of the empirical Bayes test. Results from simulated data show that the proposed approach provides accurate inference irrespective of whether parametric assumptions hold or not. Evaluation of risk factors for obesity shows that different inferences are derived from an analysis of a real data set when deviations from a logistic distribution are permissible in a flexible semiparametric framework. © 2013, The International Biometric Society.

Pembrolizumab versus the standard of care for relapsed and refractory classical Hodgkin's lymphoma progressing after brentuximab vedotin: an indirect treatment comparison.

PubMed

Keeping, Sam; Wu, Elise; Chan, Keith; Mojebi, Ali; Ferrante, Shannon Allen; Balakumaran, Arun

2018-05-15

There is significant unmet need among patients with relapsed and refractory classical Hodgkin's lymphoma (RRcHL) who have failed multiple lines of therapy, including brentuximab vedotin (BV). Pembrolizumab, an immune checkpoint inhibitor, is one possible treatment solution for this population. The objective of this study was to compare progression-free survival (PFS) with standard of care (SOC) versus pembrolizumab in previously BV treated RRcHL patients. A systematic literature review identified one observational study (Cheah et al., 2016) of SOC that was suitable for comparison with KEYNOTE-087, the principal trial of pembrolizumab in this population. Both naïve and population-adjusted (using outcomes regression) pairwise indirect comparisons were conducted. The primary analysis included all patients who had failed BV, with a secondary analysis conducted including only those known to have failed BV that was part of definitive treatment. In the primary analysis, SOC was inferior to pembrolizumab in both the unadjusted comparison (HR 5.00 [95% confidence interval (CI) 3.56-7.01]) and the adjusted comparison (HR 6.35 [95% CI 4.04-9.98]). These HRs increased to 5.16 (95% CI 3.61-7.38) and 6.56 (95% CI 4.01-10.72), respectively, in the secondary analysis. Pembrolizumab offers a significant improvement in PFS compared to SOC in this population.

Automating approximate Bayesian computation by local linear regression.

PubMed

Thornton, Kevin R

2009-07-07

In several biological contexts, parameter inference often relies on computationally-intensive techniques. "Approximate Bayesian Computation", or ABC, methods based on summary statistics have become increasingly popular. A particular flavor of ABC based on using a linear regression to approximate the posterior distribution of the parameters, conditional on the summary statistics, is computationally appealing, yet no standalone tool exists to automate the procedure. Here, I describe a program to implement the method. The software package ABCreg implements the local linear-regression approach to ABC. The advantages are: 1. The code is standalone, and fully-documented. 2. The program will automatically process multiple data sets, and create unique output files for each (which may be processed immediately in R), facilitating the testing of inference procedures on simulated data, or the analysis of multiple data sets. 3. The program implements two different transformation methods for the regression step. 4. Analysis options are controlled on the command line by the user, and the program is designed to output warnings for cases where the regression fails. 5. The program does not depend on any particular simulation machinery (coalescent, forward-time, etc.), and therefore is a general tool for processing the results from any simulation. 6. The code is open-source, and modular.Examples of applying the software to empirical data from Drosophila melanogaster, and testing the procedure on simulated data, are shown. In practice, the ABCreg simplifies implementing ABC based on local-linear regression.

Impact of job characteristics on psychological health of Chinese single working women.

PubMed

Yeung, D Y; Tang, C S

2001-01-01

This study aims at investigating the impact of individual and contextual job characteristics of control, psychological and physical demand, and security on psychological distress of 193 Chinese single working women in Hong Kong. The mediating role of job satisfaction in the job characteristics-distress relation is also assessed. Multiple regression analysis results show that job satisfaction mediates the effects of job control and security in predicting psychological distress; whereas psychological job demand has an independent effect on mental distress after considering the effect of job satisfaction. This main effect model indicates that psychological distress is best predicted by small company size, high psychological job demand, and low job satisfaction. Results from a separate regression analysis fails to support the overall combined effect of job demand-control on psychological distress. However, a significant physical job demand-control interaction effect on mental distress is noted, which reduces slightly after controlling the effect of job satisfaction.

Eye regression in blind Astyanax cavefish may facilitate the evolution of an adaptive behavior and its sensory receptors.

PubMed

Borowsky, Richard

2013-07-11

The forces driving the evolutionary loss or simplification of traits such as vision and pigmentation in cave animals are still debated. Three alternative hypotheses are direct selection against the trait, genetic drift, and indirect selection due to antagonistic pleiotropy. Recent work establishes that Astyanax cavefish exhibit vibration attraction behavior (VAB), a presumed behavioral adaptation to finding food in the dark not exhibited by surface fish. Genetic analysis revealed two regions in the genome with quantitative trait loci (QTL) for both VAB and eye size. These observations were interpreted as genetic evidence that selection for VAB indirectly drove eye regression through antagonistic pleiotropy and, further, that this is a general mechanism to account for regressive evolution. These conclusions are unsupported by the data; the analysis fails to establish pleiotropy and ignores the numerous other QTL that map to, and potentially interact, in the same regions. It is likely that all three forces drive evolutionary change. We will be able to distinguish among them in individual cases only when we have identified the causative alleles and characterized their effects.

Machine learning action parameters in lattice quantum chromodynamics

NASA Astrophysics Data System (ADS)

Shanahan, Phiala E.; Trewartha, Daniel; Detmold, William

2018-05-01

Numerical lattice quantum chromodynamics studies of the strong interaction are important in many aspects of particle and nuclear physics. Such studies require significant computing resources to undertake. A number of proposed methods promise improved efficiency of lattice calculations, and access to regions of parameter space that are currently computationally intractable, via multi-scale action-matching approaches that necessitate parametric regression of generated lattice datasets. The applicability of machine learning to this regression task is investigated, with deep neural networks found to provide an efficient solution even in cases where approaches such as principal component analysis fail. The high information content and complex symmetries inherent in lattice QCD datasets require custom neural network layers to be introduced and present opportunities for further development.

Clinical insomnia and associated factors in failed back surgery syndrome: a retrospective cross-sectional study.

PubMed

Yun, Soon Young; Kim, Do Heon; Do, Hae Yoon; Kim, Shin Hyung

2017-01-01

Background Insomnia frequently occurs to patients with persistent back pain. By worsening pain, mood, and physical functioning, insomnia could lead to the negative clinical consequences of patients with failed back surgery syndrome (FBSS). This retrospective and cross-sectional study aims to identify the risk factors associated with clinical insomnia in FBSS patients. Methods A total of 194 patients with FBSS, who met the study inclusion criteria, were included in this analysis. The Insomnia Severity Index (ISI) was utilized to ascertain the presence of clinical insomnia (ISI score ≥ 15). Logistic regression analysis evaluates patient demographic factors, clinical factors including prior surgical factors, and psychological factors to identify the risk factors of clinical insomnia in FBSS patients. Results After the persistent pain following lumbar spine surgery worsened, 63.4% of patients reported a change from mild to severe insomnia. In addition, 26.2% of patients met the criteria for clinically significant insomnia. In a multivariate logistic regression analysis, high pain intensity (odds ratio (OR) =2.742, 95% confidence interval (CI): 1.022 - 7.353, P =0.045), high pain catastrophizing (OR=4.185, 95% CI: 1.697 - 10.324, P =0.002), greater level of depression (OR =3.330, 95% CI: 1.127 - 9.837, P =0.030) were significantly associated with clinical insomnia. However, patient demographic factors and clinical factors including prior surgical factors were not significantly associated with clinical insomnia. Conclusions Insomnia should be addressed as a critical part of pain management in FBSS patients with these risk factors, especially in patients with high pain catastrophizing.

Detection of anatomical changes in lung cancer patients with 2D time-integrated, 2D time-resolved and 3D time-integrated portal dosimetry: a simulation study

NASA Astrophysics Data System (ADS)

Wolfs, Cecile J. A.; Brás, Mariana G.; Schyns, Lotte E. J. R.; Nijsten, Sebastiaan M. J. J. G.; van Elmpt, Wouter; Scheib, Stefan G.; Baltes, Christof; Podesta, Mark; Verhaegen, Frank

2017-08-01

The aim of this work is to assess the performance of 2D time-integrated (2D-TI), 2D time-resolved (2D-TR) and 3D time-integrated (3D-TI) portal dosimetry in detecting dose discrepancies between the planned and (simulated) delivered dose caused by simulated changes in the anatomy of lung cancer patients. For six lung cancer patients, tumor shift, tumor regression and pleural effusion are simulated by modifying their CT images. Based on the modified CT images, time-integrated (TI) and time-resolved (TR) portal dose images (PDIs) are simulated and 3D-TI doses are calculated. The modified and original PDIs and 3D doses are compared by a gamma analysis with various gamma criteria. Furthermore, the difference in the D 95% (ΔD 95%) of the GTV is calculated and used as a gold standard. The correlation between the gamma fail rate and the ΔD 95% is investigated, as well the sensitivity and specificity of all combinations of portal dosimetry method, gamma criteria and gamma fail rate threshold. On the individual patient level, there is a correlation between the gamma fail rate and the ΔD 95%, which cannot be found at the group level. The sensitivity and specificity analysis showed that there is not one combination of portal dosimetry method, gamma criteria and gamma fail rate threshold that can detect all simulated anatomical changes. This work shows that it will be more beneficial to relate portal dosimetry and DVH analysis on the patient level, rather than trying to quantify a relationship for a group of patients. With regards to optimizing sensitivity and specificity, different combinations of portal dosimetry method, gamma criteria and gamma fail rate should be used to optimally detect certain types of anatomical changes.

Detection of anatomical changes in lung cancer patients with 2D time-integrated, 2D time-resolved and 3D time-integrated portal dosimetry: a simulation study.

PubMed

Wolfs, Cecile J A; Brás, Mariana G; Schyns, Lotte E J R; Nijsten, Sebastiaan M J J G; van Elmpt, Wouter; Scheib, Stefan G; Baltes, Christof; Podesta, Mark; Verhaegen, Frank

2017-07-12

The aim of this work is to assess the performance of 2D time-integrated (2D-TI), 2D time-resolved (2D-TR) and 3D time-integrated (3D-TI) portal dosimetry in detecting dose discrepancies between the planned and (simulated) delivered dose caused by simulated changes in the anatomy of lung cancer patients. For six lung cancer patients, tumor shift, tumor regression and pleural effusion are simulated by modifying their CT images. Based on the modified CT images, time-integrated (TI) and time-resolved (TR) portal dose images (PDIs) are simulated and 3D-TI doses are calculated. The modified and original PDIs and 3D doses are compared by a gamma analysis with various gamma criteria. Furthermore, the difference in the D 95% (ΔD 95% ) of the GTV is calculated and used as a gold standard. The correlation between the gamma fail rate and the ΔD 95% is investigated, as well the sensitivity and specificity of all combinations of portal dosimetry method, gamma criteria and gamma fail rate threshold. On the individual patient level, there is a correlation between the gamma fail rate and the ΔD 95% , which cannot be found at the group level. The sensitivity and specificity analysis showed that there is not one combination of portal dosimetry method, gamma criteria and gamma fail rate threshold that can detect all simulated anatomical changes. This work shows that it will be more beneficial to relate portal dosimetry and DVH analysis on the patient level, rather than trying to quantify a relationship for a group of patients. With regards to optimizing sensitivity and specificity, different combinations of portal dosimetry method, gamma criteria and gamma fail rate should be used to optimally detect certain types of anatomical changes.

High-School Exit Examinations and the Schooling Decisions of Teenagers: Evidence From Regression-Discontinuity Approaches

PubMed Central

Papay, John P.; Murnane, Richard J.; Willett, John B.

2014-01-01

We examine whether barely failing one or more state-mandated high school exit examinations in Massachusetts affects the probability that students enroll in college. We extend the exit examination literature in two ways. First, we explore longer term effects of failing these tests. We find that barely failing an exit examination, for students on the margin of passing, reduces the probability of college attendance several years after the test. Second, we explore potential interactions that arise because students must pass exit examinations in both mathematics and English language arts in order to graduate from high school. We adopt a variety of regression-discontinuity approaches to address situations where multiple variables assign individuals to a range of treatments; some of these approaches enable us to examine whether the effect of barely failing one examination depends on student performance on the other. We document the range of causal effects estimated by each approach. We argue that each approach presents opportunities and limitations for making causal inferences in such situations and that the choice of approach should match the question of interest. PMID:25606065

Follistatin-like 1 in Chronic Systolic Heart Failure: A Marker of Left Ventricular Remodeling

PubMed Central

El-Armouche, Ali; Ouchi, Noriyuki; Tanaka, Komei; Doros, Gheorghe; Wittköpper, Katrin; Schulze, Thomas; Eschenhagen, Thomas; Walsh, Kenneth; Sam, Flora

2011-01-01

Background Follistatin-like 1 (FSTL1) is an extracellular glycoprotein that is found in human serum. Recent work suggests that FSTL1 is secreted in response to ischemic injuries and that its overexpression is protective in the heart and vasculature. Methods and Results Here, we examined serum FSTL1 levels in patients with chronic heart failure with left ventricular (LV) ejection fraction <40% (n=86). The distribution of the sample, from these chronic heart failure patients, was separated into three tertiles of low, medium and high FSTL1 levels. Serum FSTL1 levels were increased 56% above age- and gender-matched, healthy controls. Diabetes mellitus, brain natriuretic peptide level, left atrial size, LV posterior wall thickness, LV end-diastolic diameter and LV mass were significant determinants of FSTL1 serum levels by bivariate analysis. After controlling for significant covariates, FSTL1 levels predicted LV hypertrophy (as measured by LV mass index) by multivariate linear regression analysis (P<0.001). Unadjusted survival analysis demonstrated increased mortality in patients with increasing FSTL1 levels (P=0.09). After adjusting for significant parameters, patients with increased FSTL1 remained at the highest risk of death [hazard ratio (95% confidence limits) 1.028, (0.98 and 1.78)]; (P=0.26). To determine whether elevated FSTL1 may be derived from the myocardium, FSTL1 protein expression was measured in samples from explanted, failing (n=18) and non-failing human hearts (n=7). LV failing hearts showed 2.5-fold higher FSTL1 protein levels than non-failing control hearts (P<0.05). Conclusions Elevated serum FSTL1 in human heart failure patients was associated with LV hypertrophy. Further studies on the role of FSTL1 as a biomarker in chronic systolic heart failure are warranted. PMID:21622850

The clustering-based case-based reasoning for imbalanced business failure prediction: a hybrid approach through integrating unsupervised process with supervised process

NASA Astrophysics Data System (ADS)

Li, Hui; Yu, Jun-Ling; Yu, Le-An; Sun, Jie

2014-05-01

Case-based reasoning (CBR) is one of the main forecasting methods in business forecasting, which performs well in prediction and holds the ability of giving explanations for the results. In business failure prediction (BFP), the number of failed enterprises is relatively small, compared with the number of non-failed ones. However, the loss is huge when an enterprise fails. Therefore, it is necessary to develop methods (trained on imbalanced samples) which forecast well for this small proportion of failed enterprises and performs accurately on total accuracy meanwhile. Commonly used methods constructed on the assumption of balanced samples do not perform well in predicting minority samples on imbalanced samples consisting of the minority/failed enterprises and the majority/non-failed ones. This article develops a new method called clustering-based CBR (CBCBR), which integrates clustering analysis, an unsupervised process, with CBR, a supervised process, to enhance the efficiency of retrieving information from both minority and majority in CBR. In CBCBR, various case classes are firstly generated through hierarchical clustering inside stored experienced cases, and class centres are calculated out by integrating cases information in the same clustered class. When predicting the label of a target case, its nearest clustered case class is firstly retrieved by ranking similarities between the target case and each clustered case class centre. Then, nearest neighbours of the target case in the determined clustered case class are retrieved. Finally, labels of the nearest experienced cases are used in prediction. In the empirical experiment with two imbalanced samples from China, the performance of CBCBR was compared with the classical CBR, a support vector machine, a logistic regression and a multi-variant discriminate analysis. The results show that compared with the other four methods, CBCBR performed significantly better in terms of sensitivity for identifying the minority samples and generated high total accuracy meanwhile. The proposed approach makes CBR useful in imbalanced forecasting.

Evaluating effects of developmental education for college students using a regression discontinuity design.

PubMed

Moss, Brian G; Yeaton, William H

2013-10-01

Annually, American colleges and universities provide developmental education (DE) to millions of underprepared students; however, evaluation estimates of DE benefits have been mixed. Using a prototypic exemplar of DE, our primary objective was to investigate the utility of a replicative evaluative framework for assessing program effectiveness. Within the context of the regression discontinuity (RD) design, this research examined the effectiveness of a DE program for five, sequential cohorts of first-time college students. Discontinuity estimates were generated for individual terms and cumulatively, across terms. Participants were 3,589 first-time community college students. DE program effects were measured by contrasting both college-level English grades and a dichotomous measure of pass/fail, for DE and non-DE students. Parametric and nonparametric estimates of overall effect were positive for continuous and dichotomous measures of achievement (grade and pass/fail). The variability of program effects over time was determined by tracking results within individual terms and cumulatively, across terms. Applying this replication strategy, DE's overall impact was modest (an effect size of approximately .20) but quite consistent, based on parametric and nonparametric estimation approaches. A meta-analysis of five RD results yielded virtually the same estimate as the overall, parametric findings. Subset analysis, though tentative, suggested that males benefited more than females, while academic gains were comparable for different ethnicities. The cumulative, within-study comparison, replication approach offers considerable potential for the evaluation of new and existing policies, particularly when effects are relatively small, as is often the case in applied settings.

Medial versus anterior open reduction for developmental hip dislocation in age-matched patients.

PubMed

Hoellwarth, Jason S; Kim, Young-Jo; Millis, Michael B; Kasser, James R; Zurakowski, David; Matheney, Travis H

2015-01-01

The difference between medial (MAOR) and anterior (AAOR) approaches for open reduction of developmental hip dysplasia in terms of risk for avascular necrosis (AVN) and need for further corrective surgery (FCS, femoral and/or acetabular osteotomy) is unclear. This study compared age-matched cohorts undergoing either MAOR or AAOR in terms of these 2 primary outcomes. Prognostic impact of presence of ossific nucleus at time of open reduction was also investigated. Institutional review board approval was obtained. Nineteen hips (14 patients) managed by MAOR were matched with 19 hips (18 patients) managed by AAOR based on age at operation (mean 6.0; range, 1.4 to 14.9 mo). Patients with neuromuscular conditions and known connective tissue disorders were excluded. Primary outcomes assessed at minimum 2 years' follow-up included radiographic evidence of AVN (Kalamchi and MacEwen) or requiring FCS. MAOR and AAOR cohorts were similar regarding age at open reduction, sex, laterality, and follow-up duration. One hip in each group had AVN before open reduction thus were excluded from AVN analysis. At minimum 2 years postoperatively (mean 6.2; range, 1.8 to 11.7 y), 4/18 (22%) MAOR and 5/18 (28%) AAOR met the same criteria for AVN (P=1.0). No predictors of AVN could be identified by regression analysis. Presence of an ossific nucleus preoperatively was not a protective factor from AVN (P=0.27). FCS was required in 4/19 (21%) MAOR and 7/19 (37%) AAOR hips (P=0.48). However, 7/12 (54%) hips failing closed reduction required FCS compared with 4/26 (16%) hips without prior failed closed reduction (P=0.024). Cox regression analysis showed that patients who failed closed reduction had an annual risk of requiring FCS approximately 6 times that of patients without a history of failed closed reduction (hazard ratio=6.1; 95% CI, 1.5-24.4; P=0.009), independent of surgical approach (P=0.55) or length of follow-up (P=0.78). In this study of age-matched patients undergoing either MAOR or AAOR, we found no association between surgical approach and risk of AVN or FCS. In addition, we identified no protective benefit of a preoperative ossific nucleus in terms of development of AVN. However, failing closed reduction was associated with a 6-fold increased annual risk of requiring FCS. To the best of our knowledge, this is the first study comparing these 2 surgical techniques in an age-matched manner. It further corroborates previous studies stating that there may be no difference in risk of AVN based on surgical approach or presence of ossific nucleus preoperatively. Level III-retrospective comparative study.

Review and Recommendations for Zero-inflated Count Regression Modeling of Dental Caries Indices in Epidemiological Studies

PubMed Central

Stamm, John W.; Long, D. Leann; Kincade, Megan E.

2012-01-01

Over the past five to ten years, zero-inflated count regression models have been increasingly applied to the analysis of dental caries indices (e.g., DMFT, dfms, etc). The main reason for that is linked to the broad decline in children’s caries experience, such that dmf and DMF indices more frequently generate low or even zero counts. This article specifically reviews the application of zero-inflated Poisson and zero-inflated negative binomial regression models to dental caries, with emphasis on the description of the models and the interpretation of fitted model results given the study goals. The review finds that interpretations provided in the published caries research are often imprecise or inadvertently misleading, particularly with respect to failing to discriminate between inference for the class of susceptible persons defined by such models and inference for the sampled population in terms of overall exposure effects. Recommendations are provided to enhance the use as well as the interpretation and reporting of results of count regression models when applied to epidemiological studies of dental caries. PMID:22710271

Machine learning action parameters in lattice quantum chromodynamics

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

Shanahan, Phiala; Trewartha, Daneil; Detmold, William

Numerical lattice quantum chromodynamics studies of the strong interaction underpin theoretical understanding of many aspects of particle and nuclear physics. Such studies require significant computing resources to undertake. A number of proposed methods promise improved efficiency of lattice calculations, and access to regions of parameter space that are currently computationally intractable, via multi-scale action-matching approaches that necessitate parametric regression of generated lattice datasets. The applicability of machine learning to this regression task is investigated, with deep neural networks found to provide an efficient solution even in cases where approaches such as principal component analysis fail. Finally, the high information contentmore » and complex symmetries inherent in lattice QCD datasets require custom neural network layers to be introduced and present opportunities for further development.« less

Machine learning action parameters in lattice quantum chromodynamics

DOE PAGES

Shanahan, Phiala; Trewartha, Daneil; Detmold, William

2018-05-16

Numerical lattice quantum chromodynamics studies of the strong interaction underpin theoretical understanding of many aspects of particle and nuclear physics. Such studies require significant computing resources to undertake. A number of proposed methods promise improved efficiency of lattice calculations, and access to regions of parameter space that are currently computationally intractable, via multi-scale action-matching approaches that necessitate parametric regression of generated lattice datasets. The applicability of machine learning to this regression task is investigated, with deep neural networks found to provide an efficient solution even in cases where approaches such as principal component analysis fail. Finally, the high information contentmore » and complex symmetries inherent in lattice QCD datasets require custom neural network layers to be introduced and present opportunities for further development.« less

Analysis of Multivariate Experimental Data Using A Simplified Regression Model Search Algorithm

NASA Technical Reports Server (NTRS)

Ulbrich, Norbert M.

2013-01-01

A new regression model search algorithm was developed that may be applied to both general multivariate experimental data sets and wind tunnel strain-gage balance calibration data. The algorithm is a simplified version of a more complex algorithm that was originally developed for the NASA Ames Balance Calibration Laboratory. The new algorithm performs regression model term reduction to prevent overfitting of data. It has the advantage that it needs only about one tenth of the original algorithm's CPU time for the completion of a regression model search. In addition, extensive testing showed that the prediction accuracy of math models obtained from the simplified algorithm is similar to the prediction accuracy of math models obtained from the original algorithm. The simplified algorithm, however, cannot guarantee that search constraints related to a set of statistical quality requirements are always satisfied in the optimized regression model. Therefore, the simplified algorithm is not intended to replace the original algorithm. Instead, it may be used to generate an alternate optimized regression model of experimental data whenever the application of the original search algorithm fails or requires too much CPU time. Data from a machine calibration of NASA's MK40 force balance is used to illustrate the application of the new search algorithm.

Serum dehydroepiandrosterone sulphate, psychosocial factors and musculoskeletal pain in workers.

PubMed

Marinelli, A; Prodi, A; Pesel, G; Ronchese, F; Bovenzi, M; Negro, C; Larese Filon, F

2017-12-30

The serum level of dehydroepiandrosterone sulphate (DHEA-S) has been suggested as a biological marker of stress. To assess the association between serum DHEA-S, psychosocial factors and musculoskeletal (MS) pain in university workers. The study population included voluntary workers at the scientific departments of the University of Trieste (Italy) who underwent periodical health surveillance from January 2011 to June 2012. DHEA-S level was analysed in serum. The assessment tools included the General Health Questionnaire (GHQ) and a modified Nordic musculoskeletal symptoms questionnaire. The relation between DHEA-S, individual characteristics, pain perception and psychological factors was assessed by means of multivariable linear regression analysis. There were 189 study participants. The study population was characterized by high reward and low effort. Pain perception in the neck, shoulder, upper limbs, upper back and lower back was reported by 42, 32, 19, 29 and 43% of people, respectively. In multivariable regression analysis, gender, age and pain perception in the shoulder and upper limbs were significantly related to serum DHEA-S. Effort and overcommitment were related to shoulder and neck pain but not to DHEA-S. The GHQ score was associated with pain perception in different body sites and inversely to DHEA-S but significance was lost in multivariable regression analysis. DHEA-S was associated with age, gender and perception of MS pain, while effort-reward imbalance dimensions and GHQ score failed to reach the statistical significance in multivariable regression analysis. © The Author(s) 2017. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Using regression analysis to predict emergency patient volume at the Indianapolis 500 mile race.

PubMed

Bowdish, G E; Cordell, W H; Bock, H C; Vukov, L F

1992-10-01

Emergency physicians often plan and provide on-site medical care for mass gatherings. Most of the mass gathering literature is descriptive. Only a few studies have looked at factors such as crowd size, event characteristics, or weather in predicting numbers and types of patients at mass gatherings. We used regression analysis to relate patient volume on Race Day at the Indianapolis Motor Speedway to weather conditions and race characteristics. Race Day weather data for the years 1983 to 1989 were obtained from the National Oceanic and Atmospheric Administration. Data regarding patients treated on 1983 to 1989 Race Days were obtained from the facility hospital (Hannah Emergency Medical Center) data base. Regression analysis was performed using weather factors and race characteristics as independent variables and number of patients seen as the dependent variable. Data from 1990 were used to test the validity of the model. There was a significant relationship between dew point (which is calculated from temperature and humidity) and patient load (P less than .01). Dew point, however, failed to predict patient load during the 1990 race. No relationships could be established between humidity, sunshine, wind, or race characteristics and number of patients. Although higher dew point was associated with higher patient load during the 1983 to 1989 races, dew point was a poor predictor of patient load during the 1990 race. Regression analysis may be useful in identifying relationships between event characteristics and patient load but is probably inadequate to explain the complexities of crowd behavior and too simplified to use as a prediction tool.

Adulteration of Argentinean milk fats with animal fats: Detection by fatty acids analysis and multivariate regression techniques.

PubMed

Rebechi, S R; Vélez, M A; Vaira, S; Perotti, M C

2016-02-01

The aims of the present study were to test the accuracy of the fatty acid ratios established by the Argentinean Legislation to detect adulterations of milk fat with animal fats and to propose a regression model suitable to evaluate these adulterations. For this purpose, 70 milk fat, 10 tallow and 7 lard fat samples were collected and analyzed by gas chromatography. Data was utilized to simulate arithmetically adulterated milk fat samples at 0%, 2%, 5%, 10% and 15%, for both animal fats. The fatty acids ratios failed to distinguish adulterated milk fats containing less than 15% of tallow or lard. For each adulterant, Multiple Linear Regression (MLR) was applied, and a model was chosen and validated. For that, calibration and validation matrices were constructed employing genuine and adulterated milk fat samples. The models were able to detect adulterations of milk fat at levels greater than 10% for tallow and 5% for lard. Copyright © 2015 Elsevier Ltd. All rights reserved.

The experimenters' regress reconsidered: Replication, tacit knowledge, and the dynamics of knowledge generation.

PubMed

Feest, Uljana

2016-08-01

This paper revisits the debate between Harry Collins and Allan Franklin, concerning the experimenters' regress. Focusing my attention on a case study from recent psychology (regarding experimental evidence for the existence of a Mozart Effect), I argue that Franklin is right to highlight the role of epistemological strategies in scientific practice, but that his account does not sufficiently appreciate Collins's point about the importance of tacit knowledge in experimental practice. In turn, Collins rightly highlights the epistemic uncertainty (and skepticism) surrounding much experimental research. However, I will argue that his analysis of tacit knowledge fails to elucidate the reasons why scientists often are (and should be) skeptical of other researchers' experimental results. I will present an analysis of tacit knowledge in experimental research that not only answers to this desideratum, but also shows how such skepticism can in fact be a vital enabling factor for the dynamic processes of experimental knowledge generation. Copyright © 2016 Elsevier Ltd. All rights reserved.

The problem of natural funnel asymmetries: a simulation analysis of meta-analysis in macroeconomics.

PubMed

Callot, Laurent; Paldam, Martin

2011-06-01

Effect sizes in macroeconomic are estimated by regressions on data published by statistical agencies. Funnel plots are a representation of the distribution of the resulting regression coefficients. They are normally much wider than predicted by the t-ratio of the coefficients and often asymmetric. The standard method of meta-analysts in economics assumes that the asymmetries are because of publication bias causing censoring and adjusts the average accordingly. The paper shows that some funnel asymmetries may be 'natural' so that they occur without censoring. We investigate such asymmetries by simulating funnels by pairs of data generating processes (DGPs) and estimating models (EMs), in which the EM has the problem that it disregards a property of the DGP. The problems are data dependency, structural breaks, non-normal residuals, non-linearity, and omitted variables. We show that some of these problems generate funnel asymmetries. When they do, the standard method often fails. Copyright © 2011 John Wiley & Sons, Ltd. Copyright © 2011 John Wiley & Sons, Ltd.

Risk factor assessment to anticipate performance in the National Developmental Screening Test in children from a disadvantaged area.

PubMed

Montes, Alejandro; Pazos, Gustavo

2016-02-01

Identifying children at risk of failing the National Developmental Screening Test by combining prevalences of children suspected of having inapparent developmental disorders (IDDs) and associated risk factors (RFs) would allow to save resources. 1. To estimate the prevalence of children suspected of having IDDs. 2. To identify associated RFs. 3. To assess three methods developed based on observed RFs and propose a pre-screening procedure. The National Developmental Screening Test was administered to 60 randomly selected children aged between 2 and 4 years old from a socioeconomically disadvantaged area from Puerto Madryn. Twenty-four biological and socioenvironmental outcome measures were assessed in order to identify potential RFs using bivariate and multivariate analyses. The likelihood of failing the screening test was estimated as follows: 1. a multivariate logistic regression model was developed; 2. a relationship was established between the number of RFs present in each child and the percentage of children who failed the test; 3. these two methods were combined. The prevalence of children suspected of having IDDs was 55.0% (95% confidence interval: 42.4%-67.6%). Six RFs were initially identified using the bivariate approach. Three of them (maternal education, number of health checkups and Z scores for height-for-age, and maternal age) were included in the logistic regression model, which has a greater explanatory power. The third method included in the assessment showed greater sensitivity and specificity (85% and 79%, respectively). The estimated prevalence of children suspected of having IDDs was four times higher than the national standards. Seven RFs were identified. Combining the analysis of risk factor accumulation and a multivariate model provides a firm basis for developing a sensitive, specific and practical pre-screening procedure for socioeconomically disadvantaged areas. Sociedad Argentina de Pediatría.

An appraisal of convergence failures in the application of logistic regression model in published manuscripts.

PubMed

Yusuf, O B; Bamgboye, E A; Afolabi, R F; Shodimu, M A

2014-09-01

Logistic regression model is widely used in health research for description and predictive purposes. Unfortunately, most researchers are sometimes not aware that the underlying principles of the techniques have failed when the algorithm for maximum likelihood does not converge. Young researchers particularly postgraduate students may not know why separation problem whether quasi or complete occurs, how to identify it and how to fix it. This study was designed to critically evaluate convergence issues in articles that employed logistic regression analysis published in an African Journal of Medicine and medical sciences between 2004 and 2013. Problems of quasi or complete separation were described and were illustrated with the National Demographic and Health Survey dataset. A critical evaluation of articles that employed logistic regression was conducted. A total of 581 articles was reviewed, of which 40 (6.9%) used binary logistic regression. Twenty-four (60.0%) stated the use of logistic regression model in the methodology while none of the articles assessed model fit. Only 3 (12.5%) properly described the procedures. Of the 40 that used the logistic regression model, the problem of convergence occurred in 6 (15.0%) of the articles. Logistic regression tends to be poorly reported in studies published between 2004 and 2013. Our findings showed that the procedure may not be well understood by researchers since very few described the process in their reports and may be totally unaware of the problem of convergence or how to deal with it.

Analysis of Multivariate Experimental Data Using A Simplified Regression Model Search Algorithm

NASA Technical Reports Server (NTRS)

Ulbrich, Norbert Manfred

2013-01-01

A new regression model search algorithm was developed in 2011 that may be used to analyze both general multivariate experimental data sets and wind tunnel strain-gage balance calibration data. The new algorithm is a simplified version of a more complex search algorithm that was originally developed at the NASA Ames Balance Calibration Laboratory. The new algorithm has the advantage that it needs only about one tenth of the original algorithm's CPU time for the completion of a search. In addition, extensive testing showed that the prediction accuracy of math models obtained from the simplified algorithm is similar to the prediction accuracy of math models obtained from the original algorithm. The simplified algorithm, however, cannot guarantee that search constraints related to a set of statistical quality requirements are always satisfied in the optimized regression models. Therefore, the simplified search algorithm is not intended to replace the original search algorithm. Instead, it may be used to generate an alternate optimized regression model of experimental data whenever the application of the original search algorithm either fails or requires too much CPU time. Data from a machine calibration of NASA's MK40 force balance is used to illustrate the application of the new regression model search algorithm.

Regression mixture models: Does modeling the covariance between independent variables and latent classes improve the results?

PubMed Central

Lamont, Andrea E.; Vermunt, Jeroen K.; Van Horn, M. Lee

2016-01-01

Regression mixture models are increasingly used as an exploratory approach to identify heterogeneity in the effects of a predictor on an outcome. In this simulation study, we test the effects of violating an implicit assumption often made in these models – i.e., independent variables in the model are not directly related to latent classes. Results indicated that the major risk of failing to model the relationship between predictor and latent class was an increase in the probability of selecting additional latent classes and biased class proportions. Additionally, this study tests whether regression mixture models can detect a piecewise relationship between a predictor and outcome. Results suggest that these models are able to detect piecewise relations, but only when the relationship between the latent class and the predictor is included in model estimation. We illustrate the implications of making this assumption through a re-analysis of applied data examining heterogeneity in the effects of family resources on academic achievement. We compare previous results (which assumed no relation between independent variables and latent class) to the model where this assumption is lifted. Implications and analytic suggestions for conducting regression mixture based on these findings are noted. PMID:26881956

Patterns and Predictors of Failed and Sustained Return-to-Work in Transport Injury Insurance Claimants.

PubMed

Gray, Shannon E; Hassani-Mahmooei, Behrooz; Cameron, Ian D; Kendall, Elizabeth; Kenardy, Justin; Collie, Alex

2018-02-12

Purpose To determine the incidence of employed people who try and fail to return-to-work (RTW) following a transport crash. To identify predictors of RTW failure. A historical cohort study was conducted in the state of Victoria, Australia. People insured through the state-based compulsory third party transport accident compensation scheme were included. Inclusion criteria included date of crash between 2003 and 2012 (inclusive), age 15-70 years at the time of crash, sustained a non-catastrophic injury and received at least 1 day of income replacement. A matrix was created from an administrative payments dataset that mapped their RTW pattern for each day up to 3 years' post-crash. A gap of 7 days of no payment followed by resumption of a payment was considered a RTW failure and was flagged. These event flags were then entered into a regression analysis to determine the odds of having a failed RTW attempt. 17% of individuals had a RTW fail, with males having 20% lower odds of experiencing RTW failure. Those who were younger, had minor injuries (sprains, strains, contusions, abrasions, non-limb fractures), or were from more advantaged socio-economic group, were less likely to experience a RTW failure. Most likely to experience a RTW failure were individuals with whiplash, dislocations or particularly those admitted to hospital. Understanding the causes and predictors of failed RTW can help insurers, employers and health systems identify at-risk individuals. This can enable earlier and more targeted support and more effective employment outcomes.

Improved amputation-free survival in unreconstructable critical limb ischemia and its implications for clinical trial design and quality measurement.

PubMed

Benoit, Eric; O'Donnell, Thomas F; Kitsios, Georgios D; Iafrati, Mark D

2012-03-01

Amputation-free survival (AFS), a composite endpoint of mortality and amputation, is the preferred outcome measure in critical limb ischemia (CLI). Given the improvements in systemic management of atherosclerosis and interventional management of limb ischemia over the past 2 decades, we examined whether these outcomes have changed in patients with CLI without revascularization options (no option-critical limb ischemia [NO-CLI]). We reviewed the literature for published 1-year AFS, mortality, and amputation rates from control groups in NO-CLI trials. Summary proportions of events were estimated by conducting a random effects meta-analysis of proportions. To determine whether there had been any change in event rates over time, we performed a random effects meta-regression and a mixed effects logistic regression, both regressed against the variable "final year of recruitment." Eleven trials consisting of 886 patients satisfied search criteria, 7 of which presented AFS data. Summary proportion of events (95% confidence interval) were 0.551 (0.399 to 0.693) for AFS; 0.198 (0.116 to 0.317) for death; and 0.341 (0.209 to 0.487) for amputation. Regression analyses demonstrated that AFS has risen over time as mortality rates have fallen, and these improvements are statistically significant. The decrease in amputation rates failed to reach statistical significance. The lack of published data precluded a quantitative evaluation of any change in the clinical severity or comorbidities in the NO-CLI population. AFS and mortality rates in NO-CLI have improved over the past 2 decades. Due to declining event rates, clinical trials may underestimate treatment effects and thus fail to reach statistical significance unless sample sizes are increased or unless a subgroup with a higher event rate can be identified. Alternatively, comparing outcomes to historical values for quality measurement may overestimate treatment effects. Benchmark values of AFS and morality require periodic review and updating. Copyright © 2012 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.

Predicting on-road assessment pass and fail outcomes in older drivers with cognitive impairment using a battery of computerized sensory-motor and cognitive tests.

PubMed

Hoggarth, Petra A; Innes, Carrie R H; Dalrymple-Alford, John C; Jones, Richard D

2013-12-01

To generate a robust model of computerized sensory-motor and cognitive test performance to predict on-road driving assessment outcomes in older persons with diagnosed or suspected cognitive impairment. A logistic regression model classified pass–fail outcomes of a blinded on-road driving assessment. Generalizability of the model was tested using leave-one-out cross-validation. Three specialist clinics in New Zealand. Drivers (n=279; mean age 78.4, 65% male) with diagnosed or suspected dementia, mild cognitive impairment, unspecified cognitive impairment, or memory problems referred for a medical driving assessment. A computerized battery of sensory-motor and cognitive tests and an on-road medical driving assessment. One hundred fifty-five participants (55.5%) received an on-road fail score. Binary logistic regression correctly classified 75.6% of the sample into on-road pass and fail groups. The cross-validation indicated accuracy of the model of 72.0% with sensitivity for detecting on-road fails of 73.5%, specificity of 70.2%, positive predictive value of 75.5%, and negative predictive value of 68%. The off-road assessment prediction model resulted in a substantial number of people who were assessed as likely to fail despite passing an on-road assessment and vice versa. Thus, despite a large multicenter sample, the use of off-road tests previously found to be useful in other older populations, and a carefully constructed and tested prediction model, off-road measures have yet to be found that are sufficiently accurate to allow acceptable determination of on-road driving safety of cognitively impaired older drivers. © 2013, Copyright the Authors Journal compilation © 2013, The American Geriatrics Society.

The Impact of Being Labeled as a Persistently Lowest Achieving School: Regression Discontinuity Evidence on Consequential School Labeling

ERIC Educational Resources Information Center

Saw, Guan; Schneider, Barbara; Frank, Kenneth; Chen, I-Chien; Keesler, Venessa; Martineau, Joseph

2017-01-01

Since the No Child Left Behind Act was enacted, grading and labeling of schools as low performing have been increasingly used as means to incentivize failing schools to raise student achievement. Using statewide high school data from Michigan, our regression discontinuity analyses show that the bottom 5% of schools identified as persistently…

Model selection for marginal regression analysis of longitudinal data with missing observations and covariate measurement error.

PubMed

Shen, Chung-Wei; Chen, Yi-Hau

2015-10-01

Missing observations and covariate measurement error commonly arise in longitudinal data. However, existing methods for model selection in marginal regression analysis of longitudinal data fail to address the potential bias resulting from these issues. To tackle this problem, we propose a new model selection criterion, the Generalized Longitudinal Information Criterion, which is based on an approximately unbiased estimator for the expected quadratic error of a considered marginal model accounting for both data missingness and covariate measurement error. The simulation results reveal that the proposed method performs quite well in the presence of missing data and covariate measurement error. On the contrary, the naive procedures without taking care of such complexity in data may perform quite poorly. The proposed method is applied to data from the Taiwan Longitudinal Study on Aging to assess the relationship of depression with health and social status in the elderly, accommodating measurement error in the covariate as well as missing observations. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

The effect of high leverage points on the logistic ridge regression estimator having multicollinearity

NASA Astrophysics Data System (ADS)

Ariffin, Syaiba Balqish; Midi, Habshah

2014-06-01

This article is concerned with the performance of logistic ridge regression estimation technique in the presence of multicollinearity and high leverage points. In logistic regression, multicollinearity exists among predictors and in the information matrix. The maximum likelihood estimator suffers a huge setback in the presence of multicollinearity which cause regression estimates to have unduly large standard errors. To remedy this problem, a logistic ridge regression estimator is put forward. It is evident that the logistic ridge regression estimator outperforms the maximum likelihood approach for handling multicollinearity. The effect of high leverage points are then investigated on the performance of the logistic ridge regression estimator through real data set and simulation study. The findings signify that logistic ridge regression estimator fails to provide better parameter estimates in the presence of both high leverage points and multicollinearity.

Association between oxidative stress index and post-CPR early mortality in cardiac arrest patients: A prospective observational study.

PubMed

Yücel, Hasan; Türkdoğan, Kenan Ahmet; Zorlu, Ali; Aydın, Hüseyin; Kurt, Recep; Yılmaz, Mehmet Birhan

2015-09-01

Cardiopulmonary resuscitation (CPR) is a series of lifesaving actions that improve the chance of survival following cardiac arrest (CA). Many clinical and laboratory parameters, such as the presence of asystole, out-of-hospital CPR, and duration of cardiac arrest, are associated with failed CPR in patients with CA. Asystole is a state of no cardiac electrical activity, along with the absence of contractions of the myocardium and absence of cardiac output. Oxidative stress index (OSI), which is the ratio of total oxidative status to total antioxidant status, increases by ischemia-reperfusion injury. We investigated whether OSI levels in patients with CA could predict early mortality after CPR. This study has a prospective observational cohort design. Five patients with a history of cancer, four patients who developed hemolysis in their blood, six patients who were transferred to our hospital from other hospitals, and six patients in whom blood samples for OSI could not be stored properly were excluded. Finally, a total of 90 in-hospital or out-of-hospital CA patients and 40 age- and sex-matched healthy volunteers as the control group were evaluated prospectively. The patients were classified according to the CPR response into a successful group (n=46) and a failed group (n=44). Comparisons between groups were performed using one-way ANOVA with post hoc analysis by Tukey's HSD or independent samples t-test and the Kruskal-Wallis tests or Mann- Whitney U test for normally and abnormally distributed data, respectively. Also, we used chi-square test, Spearman's correlation test, univariate and multible logistic regression analyses, and receiver operator characteristic curve analysis. OSI was 3.0±4.0, 5.6±4.3, and 8.7±3.8 in the control group, the successful CPR group, and the failed CPR group, respectively (p<0.001 for the 2 comparisons). OSI on admission, ischemia-modified albumin, presence of asystole, mean duration of cardiac arrest, out-of-hospital CPR, pH, and potassium and sodium levels were found to have prognostic significance in the univariate analysis. In the multivariate logistic regression model, OSI on admission (OR=1.325, p=0.003), ischemia-modified albumin (OR=1.008, p=0.005), presence of asystole (OR=13.576, p<0.001), and sodium level (OR=1.132, p=0.029) remained associated with an increased risk of early mortality. In addition, the optimal cut-off value of OSI to predict post-CPR mortality was measured as >6.02, with 84.1% sensitivity and 76.1% specificity. Elevated OSI levels can predict failed CPR in CA patients.

Efficacy of oral moxifloxacin for aerobic vaginitis.

PubMed

Wang, C; Han, C; Geng, N; Fan, A; Wang, Y; Yue, Y; Zhang, H; Xue, F

2016-01-01

The purpose of this study was to investigate the therapeutic efficacy of oral moxifloxacin for aerobic vaginitis (AV). We also identified factors that are associated with therapeutic efficacy. This prospective study enrolled general gynecological outpatients at Tianjin Medical University General Hospital between September 2012 and May 2014. Women diagnosed with AV (n = 102) were recruited. All enrolled women were treated with oral moxifloxacin, 400 mg once daily for 6 days (one course). Therapeutic efficacy was evaluated based on microscopic criteria, and cure rates were calculated. Women who were microscopically improved (but not cured) received a second course of therapy. Women classified with microscopic failure were treated using other strategies. Univariate and multivariate logistic regression analysis was used to identify factors that may be associated with a cure after one course of therapy. After one course of therapy, 65.7 % (67/102) of women were cured, 29.4 % (30/102) of women were improved (but not cured), 4.9 % (5/102) of women failed to respond to the therapy. After two courses of therapy, 85.3 % (87/102) of women were cured, 9.8 % (10/102) of women were improved, 4.9 % (5/102) of women failed to respond to the therapy, and clinical improvement was achieved in additional women. In the multivariate logistic regression analysis, women with a baseline vaginal pH value of <5.0 had a 3.5-times higher chance of being cured, compared with those with a baseline vaginal pH value of ≥5.0 (OR, 3.503; 95 % CI, 1.278-9.601). Moxifloxacin is an effective therapeutic option for patients with AV. Most women with AV were cured with one course of moxifloxacin. For those with a higher vaginal pH value of ≥5.0 before treatment, two courses of therapy should be considered.

Relationship between COMLEX-USA scores and performance on the American Osteopathic Board of Emergency Medicine Part I certifying examination.

PubMed

Li, Feiming; Gimpel, John R; Arenson, Ethan; Song, Hao; Bates, Bruce P; Ludwin, Fredric

2014-04-01

Few studies have investigated how well scores from the Comprehensive Osteopathic Medical Licensing Examination-USA (COMLEX-USA) series predict resident outcomes, such as performance on board certification examinations. To determine how well COMLEX-USA predicts performance on the American Osteopathic Board of Emergency Medicine (AOBEM) Part I certification examination. The target study population was first-time examinees who took AOBEM Part I in 2011 and 2012 with matched performances on COMLEX-USA Level 1, Level 2-Cognitive Evaluation (CE), and Level 3. Pearson correlations were computed between AOBEM Part I first-attempt scores and COMLEX-USA performances to measure the association between these examinations. Stepwise linear regression analysis was conducted to predict AOBEM Part I scores by the 3 COMLEX-USA scores. An independent t test was conducted to compare mean COMLEX-USA performances between candidates who passed and who failed AOBEM Part I, and a stepwise logistic regression analysis was used to predict the log-odds of passing AOBEM Part I on the basis of COMLEX-USA scores. Scores from AOBEM Part I had the highest correlation with COMLEX-USA Level 3 scores (.57) and slightly lower correlation with COMLEX-USA Level 2-CE scores (.53). The lowest correlation was between AOBEM Part I and COMLEX-USA Level 1 scores (.47). According to the stepwise regression model, COMLEX-USA Level 1 and Level 2-CE scores, which residency programs often use as selection criteria, together explained 30% of variance in AOBEM Part I scores. Adding Level 3 scores explained 37% of variance. The independent t test indicated that the 397 examinees passing AOBEM Part I performed significantly better than the 54 examinees failing AOBEM Part I in all 3 COMLEX-USA levels (P<.001 for all 3 levels). The logistic regression model showed that COMLEX-USA Level 1 and Level 3 scores predicted the log-odds of passing AOBEM Part I (P=.03 and P<.001, respectively). The present study empirically supported the predictive and discriminant validities of the COMLEX-USA series in relation to the AOBEM Part I certification examination. Although residency programs may use COMLEX-USA Level 1 and Level 2-CE scores as partial criteria in selecting residents, Level 3 scores, though typically not available at the time of application, are actually the most statistically related to performances on AOBEM Part I.

Challenges Associated with Estimating Utility in Wet Age-Related Macular Degeneration: A Novel Regression Analysis to Capture the Bilateral Nature of the Disease.

PubMed

Hodgson, Robert; Reason, Timothy; Trueman, David; Wickstead, Rose; Kusel, Jeanette; Jasilek, Adam; Claxton, Lindsay; Taylor, Matthew; Pulikottil-Jacob, Ruth

2017-10-01

The estimation of utility values for the economic evaluation of therapies for wet age-related macular degeneration (AMD) is a particular challenge. Previous economic models in wet AMD have been criticized for failing to capture the bilateral nature of wet AMD by modelling visual acuity (VA) and utility values associated with the better-seeing eye only. Here we present a de novo regression analysis using generalized estimating equations (GEE) applied to a previous dataset of time trade-off (TTO)-derived utility values from a sample of the UK population that wore contact lenses to simulate visual deterioration in wet AMD. This analysis allows utility values to be estimated as a function of VA in both the better-seeing eye (BSE) and worse-seeing eye (WSE). VAs in both the BSE and WSE were found to be statistically significant (p < 0.05) when regressed separately. When included without an interaction term, only the coefficient for VA in the BSE was significant (p = 0.04), but when an interaction term between VA in the BSE and WSE was included, only the constant term (mean TTO utility value) was significant, potentially a result of the collinearity between the VA of the two eyes. The lack of both formal model fit statistics from the GEE approach and theoretical knowledge to support the superiority of one model over another make it difficult to select the best model. Limitations of this analysis arise from the potential influence of collinearity between the VA of both eyes, and the use of contact lenses to reflect VA states to obtain the original dataset. Whilst further research is required to elicit more accurate utility values for wet AMD, this novel regression analysis provides a possible source of utility values to allow future economic models to capture the quality of life impact of changes in VA in both eyes. Novartis Pharmaceuticals UK Limited.

Resident performance on the in-training and board examinations in obstetrics and gynecology: implications for the ACGME Outcome Project.

PubMed

Withiam-Leitch, Matthew; Olawaiye, Alexander

2008-01-01

The Accreditation Council on Graduate Medical Education (ACGME) Outcomes Project has endorsed the in-training examination (ITE) as an example of a multiple-choice question examination that is a valid measure of a resident's attainment of medical knowledge. An outcome measure for performance on the ITE would be the subsequent performance on the board certification examination. However, there are few reports that attempt to correlate a resident's performance on the ITE to subsequent performance on the board certification examination. The Council on Resident Education in Obstetrics and Gynecology (CREOG) has administered the ITE annually since 1970. This study tested the hypothesis that the CREOG-ITE score is a valid assessment tool to predict performance on the American Board of Obstetrics and Gynecology (ABOG) written examination. CREOG-ITE and ABOG written board examination results were collected for 69 resident graduates between the years 1998 and 2005. Logistic regression and receiver operating characteristic analyses were used to estimate the relationship between a resident's score on the CREOG-ITE and subsequent performance on the ABOG written examination. Fifty-seven resident graduates passed (82.6%) and 12 graduates failed (17.4%) the ABOG written examination. The correlation between the CREOG-ITE overall score and performance on the ABOG examination was weak (correlation coefficient =.38, p =.001). Receiver operating characteristic analysis for the CREOG-ITE overall scores and the probability of passing or failing the ABOG examination revealed moderate accuracy (area under the curve = 0.77, 95% CI = 0.62-0.92) with a CREOG-ITE score of 187.5 yielding the best trade-off between specificity (0.79) and sensitivity (0.75). At the cutoff value of 187.5 there was a weak positive predictive value of 43% (i.e., 43% of residents with a score less than 187.5 will fail the ABOG exam) and a strong negative predictive value of 94% (i.e., 94% of the residents with a score above 187.5 will pass the ABOG exam). Logistic regression analysis also revealed a statistically significant relationship between the CREOG-ITE overall score and performance on the ABOG written examination (p = .003). Similar to other specialties, resident performance on the CREOG-ITE is a weak assessment tool to predict the probability of a resident failing the ABOG written examination. Our study highlights the need, in the spirit of the ACGME Outcome Project, for residency and board specialty organizations to coordinate efforts to develop more reliable and correlative measures of a resident's medical knowledge and ability to pass the boards.

Using within-day hive weight changes to measure environmental effects on honey bee colonies

PubMed Central

Holst, Niels; Weiss, Milagra; Carroll, Mark J.; McFrederick, Quinn S.; Barron, Andrew B.

2018-01-01

Patterns in within-day hive weight data from two independent datasets in Arizona and California were modeled using piecewise regression, and analyzed with respect to honey bee colony behavior and landscape effects. The regression analysis yielded information on the start and finish of a colony’s daily activity cycle, hive weight change at night, hive weight loss due to departing foragers and weight gain due to returning foragers. Assumptions about the meaning of the timing and size of the morning weight changes were tested in a third study by delaying the forager departure times from one to three hours using screen entrance gates. A regression of planned vs. observed departure delays showed that the initial hive weight loss around dawn was largely due to foragers. In a similar experiment in Australia, hive weight loss due to departing foragers in the morning was correlated with net bee traffic (difference between the number of departing bees and the number of arriving bees) and from those data the payload of the arriving bees was estimated to be 0.02 g. The piecewise regression approach was then used to analyze a fifth study involving hives with and without access to natural forage. The analysis showed that, during a commercial pollination event, hives with previous access to forage had a significantly higher rate of weight gain as the foragers returned in the afternoon, and, in the weeks after the pollination event, a significantly higher rate of weight loss in the morning, as foragers departed. This combination of continuous weight data and piecewise regression proved effective in detecting treatment differences in foraging activity that other methods failed to detect. PMID:29791462

Regression Rates Following the Treatment of Aggressive Posterior Retinopathy of Prematurity with Bevacizumab Versus Laser: 8-Year Retrospective Analysis

PubMed Central

Nicoară, Simona D.; Ştefănuţ, Anne C.; Nascutzy, Constanta; Zaharie, Gabriela C.; Toader, Laura E.; Drugan, Tudor C.

2016-01-01

Background Retinopathy is a serious complication related to prematurity and a leading cause of childhood blindness. The aggressive posterior form of retinopathy of prematurity (APROP) has a worse anatomical and functional outcome following laser therapy, as compared with the classic form of the disease. The main outcome measures are the APROP regression rate, structural outcomes, and complications associated with intravitreal bevacizumab (IVB) versus laser photocoagulation in APROP. Material/Methods This is a retrospective case series that includes infants with APROP who received either IVB or laser photocoagulation and had a follow-up of at least 60 weeks (for the laser photocoagulation group) and 80 weeks (for the IVB group). In the first group, laser photocoagulation of the retina was carried out and in the second group, 1 bevacizumab injection was administered intravitreally. The following parameters were analyzed in each group: sex, gestational age, birth weight, postnatal age and postmenstrual age at treatment, APROP regression, sequelae, and complications. Statistical analysis was performed using Microsoft Excel and IBM SPSS (version 23.0). Results The laser photocoagulation group consisted of 6 premature infants (12 eyes) and the IVB group consisted of 17 premature infants (34 eyes). Within the laser photocoagulation group, the evolution was favorable in 9 eyes (75%) and unfavorable in 3 eyes (25%). Within the IVB group, APROP regressed in 29 eyes (85.29%) and failed to regress in 5 eyes (14.71%). These differences are statistically significant, as proved by the McNemar test (P<0.001). Conclusions The IVB group had a statistically significant better outcome compared with the laser photocoagulation group, in APROP in our series. PMID:27062023

Using within-day hive weight changes to measure environmental effects on honey bee colonies.

PubMed

Meikle, William G; Holst, Niels; Colin, Théotime; Weiss, Milagra; Carroll, Mark J; McFrederick, Quinn S; Barron, Andrew B

2018-01-01

Patterns in within-day hive weight data from two independent datasets in Arizona and California were modeled using piecewise regression, and analyzed with respect to honey bee colony behavior and landscape effects. The regression analysis yielded information on the start and finish of a colony's daily activity cycle, hive weight change at night, hive weight loss due to departing foragers and weight gain due to returning foragers. Assumptions about the meaning of the timing and size of the morning weight changes were tested in a third study by delaying the forager departure times from one to three hours using screen entrance gates. A regression of planned vs. observed departure delays showed that the initial hive weight loss around dawn was largely due to foragers. In a similar experiment in Australia, hive weight loss due to departing foragers in the morning was correlated with net bee traffic (difference between the number of departing bees and the number of arriving bees) and from those data the payload of the arriving bees was estimated to be 0.02 g. The piecewise regression approach was then used to analyze a fifth study involving hives with and without access to natural forage. The analysis showed that, during a commercial pollination event, hives with previous access to forage had a significantly higher rate of weight gain as the foragers returned in the afternoon, and, in the weeks after the pollination event, a significantly higher rate of weight loss in the morning, as foragers departed. This combination of continuous weight data and piecewise regression proved effective in detecting treatment differences in foraging activity that other methods failed to detect.

Analysis and prediction of flow from local source in a river basin using a Neuro-fuzzy modeling tool.

PubMed

Aqil, Muhammad; Kita, Ichiro; Yano, Akira; Nishiyama, Soichi

2007-10-01

Traditionally, the multiple linear regression technique has been one of the most widely used models in simulating hydrological time series. However, when the nonlinear phenomenon is significant, the multiple linear will fail to develop an appropriate predictive model. Recently, neuro-fuzzy systems have gained much popularity for calibrating the nonlinear relationships. This study evaluated the potential of a neuro-fuzzy system as an alternative to the traditional statistical regression technique for the purpose of predicting flow from a local source in a river basin. The effectiveness of the proposed identification technique was demonstrated through a simulation study of the river flow time series of the Citarum River in Indonesia. Furthermore, in order to provide the uncertainty associated with the estimation of river flow, a Monte Carlo simulation was performed. As a comparison, a multiple linear regression analysis that was being used by the Citarum River Authority was also examined using various statistical indices. The simulation results using 95% confidence intervals indicated that the neuro-fuzzy model consistently underestimated the magnitude of high flow while the low and medium flow magnitudes were estimated closer to the observed data. The comparison of the prediction accuracy of the neuro-fuzzy and linear regression methods indicated that the neuro-fuzzy approach was more accurate in predicting river flow dynamics. The neuro-fuzzy model was able to improve the root mean square error (RMSE) and mean absolute percentage error (MAPE) values of the multiple linear regression forecasts by about 13.52% and 10.73%, respectively. Considering its simplicity and efficiency, the neuro-fuzzy model is recommended as an alternative tool for modeling of flow dynamics in the study area.

Susceptibility of black soldier fly (Diptera: Stratiomyidae) larvae and adults to four insecticides.

PubMed

Tomberlin, Jeffery K; Sheppard, D Craig; Joyce, John A

2002-06-01

Dosage-mortality regressions were determined for black soldier fly, Hermetia illucens (L.), larvae fed cyromazine or pyriproxifen treated media. Cyromazine LC50 for larvae dying before becoming prepupae ranged from 0.25 to 0.28 ppm with dosage-mortality regression slopes between 5.79 and 12.04. Cyromazine LC50s for larvae dying before emergence ranged from 0.13 to 0.19 ppm with dosage-mortality regression slopes between 3.94 and 7.69. Pyriproxifen dosage-mortality regressions were not generated for larvae failing to become prepupae since <32% mortality was recorded at the highest concentration of 1,857 ppm. LC50s for larvae failing to become adults ranged from 0.10 to 0.12 ppm with dosage mortality-regression slopes between 1.67 and 2.32. Lambda-cyhalothrin and permethrin dosage-mortality regressions were determined for wild adult black soldier flies and house flies, Musca domestica L., and for susceptible house flies. Our results indicate that the wild house fly, unlike the black soldier fly, population was highly resistant to each of these pyrethroids. Regression slopes for black soldier flies exposed to lambda-cyhalothrin were twice as steep as those determined for the wild house fly strain. Accordingly, LC50s for the black soldier fly and susceptible house fly were 10- to 30-fold lower than those determined for wild house flies. The differential sensitivity between wild black soldier flies and house flies might be due to behavioral differences. Adult house flies usually remain in animal facilities with the possibility of every adult receiving pesticide exposure, while black soldier fly adults are typically present only during emergence and oviposition thereby limiting their exposure.

Estimating Procurement Cost Growth Using Logistic and Multiple Regression

DTIC Science & Technology

2003-03-01

Figure 4). The plots fail to pass the visual inspection for constant variance as well as the Breusch - Pagan test (Neter, 1996: 112) at an alpha level...plots fail to pass the visual inspection for constant variance as well as the Breusch - Pagan test at an alpha level of 0.05. Based on these findings...amount of cost growth a program will have 13 once model A deems that the program will incur cost growth. Sipple conducts validation testing on

Influence of enamel preservation on failure rates of porcelain laminate veneers.

PubMed

Gurel, Galip; Sesma, Newton; Calamita, Marcelo A; Coachman, Christian; Morimoto, Susana

2013-01-01

The purpose of this study was to evaluate the failure rates of porcelain laminate veneers (PLVs) and the influence of clinical parameters on these rates in a retrospective survey of up to 12 years. Five hundred eighty laminate veneers were bonded in 66 patients. The following parameters were analyzed: type of preparation (depth and margin), crown lengthening, presence of restoration, diastema, crowding, discoloration, abrasion, and attrition. Survival was analyzed using the Kaplan-Meier method. Cox regression modeling was used to determine which factors would predict PLV failure. Forty-two veneers (7.2%) failed in 23 patients, and an overall cumulative survival rate of 86% was observed. A statistically significant association was noted between failure and the limits of the prepared tooth surface (margin and depth). The most frequent failure type was fracture (n = 20). The results revealed no significant influence of crown lengthening apically, presence of restoration, diastema, discoloration, abrasion, or attrition on failure rates. Multivariable analysis (Cox regression model) also showed that PLVs bonded to dentin and teeth with preparation margins in dentin were approximately 10 times more likely to fail than PLVs bonded to enamel. Moreover, coronal crown lengthening increased the risk of PLV failure by 2.3 times. A survival rate of 99% was observed for veneers with preparations confined to enamel and 94% for veneers with enamel only at the margins. Laminate veneers have high survival rates when bonded to enamel and provide a safe and predictable treatment option that preserves tooth structure.

Adolescent sexual victimization: a prospective study on risk factors for first time sexual assault.

PubMed

Bramsen, Rikke Holm; Lasgaard, Mathias; Koss, Mary P; Elklit, Ask; Banner, Jytte

2012-09-01

The present study set out to investigate predictors of first time adolescent peer-on-peer sexual victimization (APSV) among 238 female Grade 9 students from 30 schools in Denmark. A prospective research design was utilized to examine the relationship among five potential predictors as measured at baseline and first time APSV during a 6-month period. Data analysis was a binary logistic regression analysis. Number of sexual partners and displaying sexual risk behaviors significantly predicted subsequent first time peer-on-peer sexual victimization, whereas a history of child sexual abuse, early sexual onset and failing to signal sexual boundaries did not. The present study identifies specific risk factors for first time sexual victimization that are potentially changeable. Thus, the results may inform prevention initiatives targeting initial experiences of APSV.

Estimating Mixture of Gaussian Processes by Kernel Smoothing

PubMed Central

Huang, Mian; Li, Runze; Wang, Hansheng; Yao, Weixin

2014-01-01

When the functional data are not homogeneous, e.g., there exist multiple classes of functional curves in the dataset, traditional estimation methods may fail. In this paper, we propose a new estimation procedure for the Mixture of Gaussian Processes, to incorporate both functional and inhomogeneous properties of the data. Our method can be viewed as a natural extension of high-dimensional normal mixtures. However, the key difference is that smoothed structures are imposed for both the mean and covariance functions. The model is shown to be identifiable, and can be estimated efficiently by a combination of the ideas from EM algorithm, kernel regression, and functional principal component analysis. Our methodology is empirically justified by Monte Carlo simulations and illustrated by an analysis of a supermarket dataset. PMID:24976675

Blood Glucose Reduction by Diabetic Drugs with Minimal Hypoglycemia Risk for Cardiovascular Outcomes: Evidence from Meta-regression Analysis of Randomized Controlled Trials.

PubMed

Huang, Chi-Jung; Wang, Wei-Ting; Sung, Shih-Hsien; Chen, Chen-Huan; Lip, Gregory Yh; Cheng, Hao-Min; Chiang, Chern-En

2018-05-02

To investigate the effects of blood glucose control with antihyperglycemic agents with minimal hypoglycemia risk on cardiovascular outcomes in patients with type 2 diabetes (T2D). Randomized controlled trials (RCTs) comparing the relative efficacy and safety of antidiabetic drugs with less hypoglycemia risk were comprehensively searched in MEDLINE, Embase, and the Cochrane Library up to January 27, 2018. Mixed-effects meta-regression analysis was conducted to explore the relationship between haemoglobin A1c (HbA1c) reduction and the risk of major adverse cardiovascular events (MACE), myocardial infarction, stroke, cardiovascular death, all-cause death, and hospitalization for heart failure. Ten RCTs comprising 92400 participants with T2D were included and provided information on 9773 MACE during a median follow-up of 2.6 years. The mean HbA1c concentration was 0.42% lower (median, 0.27-0.86%) for participants given antihyperglycemic agents than those given placebo. The meta-regression analysis demonstrated that HbA1c reduction was significantly associated with a decreased risk of MACE (β value, -0.39 to -0.55; P<0.02) even after adjusting for each of the following possible confounding factors including age, sex, baseline HbA1c, duration of follow-up, difference in achieved systolic blood pressure, difference in achieved body weight, or risk difference in hypoglycemia. Lowering HbA1c by 1% conferred a significant risk reduction of 30% (95% CI, 17-40%) for MACE. By contrast, the meta-regression analysis for trials using conventional agents failed to demonstrate a significant relationship between achieved HbA1c difference and MACE risk (P>0.74). Compared with placebo, newer T2D agents with less hypoglycemic hazard significantly reduced the risk of MACE. The MACE reduction seems to be associated with HbA1c reduction in a linear relationship. This article is protected by copyright. All rights reserved.

Management of persistent occiput posterior position: a substantial role of instrumental rotation in the setting of failed manual rotation.

PubMed

Guerby, Paul; Allouche, Mickael; Simon-Toulza, Caroline; Vayssiere, Christophe; Parant, Olivier; Vidal, Fabien

2018-01-01

To compare the maternal and neonatal outcomes associated with Instrumental Rotation (IR) to operative vaginal delivery in occiput posterior (OP) position with Thierry's spatulas (TS), in the setting of failed manual rotation (MR). We led a prospective observational cohort study in a tertiary referral hospital in Toulouse, France. All women presenting in labor with persistent OP position at full cervical dilatation and who delivered vaginally after failed MR and with IR or OP assisted delivery were included from January 2014 to December 2015. The main outcomes measured were maternal morbidity parameters including episiotomy rate, incidence and severity of perineal lacerations, perineal hematomas and postpartum hemorrhage. Severe perineal tears corresponded to third and fourth degree lacerations. Fetal morbidity outcomes comprised neonatal Apgar scores, acidemia, fetal injuries, birth trauma and neonatal intensive care unit admissions. Among 9762 women, 910 (9.3%) presented with persistent OP position at full cervical dilatation and 222 deliveries were enrolled. Of 111 attempted IR, 97 were successful (87.4%). The incidence of anal sphincter injuries was significantly reduced after IR attempt (1.8% vs. 12.6%; p < 0.002). Both groups were similar regarding most fetal outcomes and no birth trauma occurred in our study population. In a multivariable logistic regression analysis, OP operative delivery was a significant risk factor of severe perineal lacerations (OR = 9.5; 95% CI: 2.05-44.05). Our results support the use of IR in order to reduce perineal morbidity associated with OP assisted delivery, in the setting of a failed manual rotation.

Factors affecting the results of comprehensive pre-internship exam among medical students of Kermanshah University of Medical Sciences.

PubMed

Khazaei, Mohammad Rasool; Zarin, Afshin; Rezaei, Mansuor; Khazaei, Mozafar

2018-06-01

This study was aimed to evaluate the factors affecting the results of comprehensive pre-internship exam (CPIE) among medicals students of Kermanshah University of Medical Sciences. In this descriptive-analytical study, all students (n=240) participating in CPIE over a 3-year period (2012-2014) were selected. Data were gathered by a questionnaire, including the CPIE results and educational and demographic data. Spearman correlation coefficient, Mann-Whitney U-test, and analysis of variance were used to analyze the association of students' success with study variables. Also, regression analysis was applied to determine the role of independent variables in students' success. The frequency of the failed units in apprenticeship course was one of the most important risk factors associated with failure in CPIE. Average scores of pre-internship course were the most important factors of success in CPIE. The CPIE score had the highest direct relationship with grade point average (GPA) of apprenticeship course, total GPA of all three courses, GPAs of physiopathology and basic sciences courses, and score of comprehensive basic sciences examination, respectively. CPIE showed the highest inverse correlation with the number of failed units in apprenticeship course. The most important factors influencing this exam were failure in apprenticeship course and GPA of previous educational stages.

Spatial interpolation schemes of daily precipitation for hydrologic modeling

USGS Publications Warehouse

Hwang, Y.; Clark, M.R.; Rajagopalan, B.; Leavesley, G.

2012-01-01

Distributed hydrologic models typically require spatial estimates of precipitation interpolated from sparsely located observational points to the specific grid points. We compare and contrast the performance of regression-based statistical methods for the spatial estimation of precipitation in two hydrologically different basins and confirmed that widely used regression-based estimation schemes fail to describe the realistic spatial variability of daily precipitation field. The methods assessed are: (1) inverse distance weighted average; (2) multiple linear regression (MLR); (3) climatological MLR; and (4) locally weighted polynomial regression (LWP). In order to improve the performance of the interpolations, the authors propose a two-step regression technique for effective daily precipitation estimation. In this simple two-step estimation process, precipitation occurrence is first generated via a logistic regression model before estimate the amount of precipitation separately on wet days. This process generated the precipitation occurrence, amount, and spatial correlation effectively. A distributed hydrologic model (PRMS) was used for the impact analysis in daily time step simulation. Multiple simulations suggested noticeable differences between the input alternatives generated by three different interpolation schemes. Differences are shown in overall simulation error against the observations, degree of explained variability, and seasonal volumes. Simulated streamflows also showed different characteristics in mean, maximum, minimum, and peak flows. Given the same parameter optimization technique, LWP input showed least streamflow error in Alapaha basin and CMLR input showed least error (still very close to LWP) in Animas basin. All of the two-step interpolation inputs resulted in lower streamflow error compared to the directly interpolated inputs. ?? 2011 Springer-Verlag.

Factors affecting the dissipation of pharmaceuticals in freshwater sediments.

PubMed

Al-Khazrajy, Omar S A; Bergström, Ed; Boxall, Alistair B A

2018-03-01

Degradation is one of the key processes governing the impact of pharmaceuticals in the aquatic environment. Most studies on the degradation of pharmaceuticals have focused on soil and sludge, with fewer exploring persistence in aquatic sediments. We investigated the dissipation of 6 pharmaceuticals from different therapeutic classes in a range of sediment types. Dissipation of each pharmaceutical was found to follow first-order exponential decay. Half-lives in the sediments ranged from 9.5 (atenolol) to 78.8 (amitriptyline) d. Under sterile conditions, the persistence of pharmaceuticals was considerably longer. Stepwise multiple linear regression analysis was performed to explore the relationships between half-lives of the pharmaceuticals, sediment physicochemical properties, and sorption coefficients for the compounds. Sediment clay, silt, and organic carbon content and microbial activity were the predominant factors related to the degradation rates of diltiazem, cimetidine, and ranitidine. Regression analysis failed to highlight a key property which may be responsible for observed differences in the degradation of the other pharmaceuticals. The present results suggest that the degradation rate of pharmaceuticals in sediments is determined by different factors and processes and does not exclusively depend on a single sediment parameter. Environ Toxicol Chem 2018;37:829-838. © 2017 SETAC. © 2017 SETAC.

Glyburide in gestational diabetes--prediction of treatment failure.

PubMed

Yogev, Yariv; Melamed, Nir; Chen, Rony; Nassie, Daniel; Pardo, Joseph; Hod, Moshe

2011-06-01

To identify factors predicting failure of glyburide treatment in women with gestational diabetes mellitus (GDM). A retrospective study of all women with GDM that were treated with glyburide in a single tertiary referral center. Patients were switched from glyburide to insulin if they failed to achieve glycemic goals, and were then classified as glyburide failure. Overall, 124 women with GDM treated with glyburide were included in the study, of which 31 (25%) failed to achieve glycemic control. Women in the failure group were characterized by a higher weight gain during pregnancy, higher rates of GDM on previous pregnancies, and a glucose challenge test (GCT) result. On multivariate logistic regression analysis, a GCT value of >200 mg/dl (OR = 7.1, 95% CI 2.8-27.6) and weight gain ≥ 12 kg (OR = 3.9, 95% CI 1.2-13.0) were the only significant and independent predictors of glyburide failure. Most women who were successfully treated with glyburide required a daily dose of 5 mg or less and the time required to achieve glycemic control in these cases was 12.4 ± 4.9 days (range 5-24 days). Of the women who failed to achieve glycemic control with gluburide, 26/31 were switched to insulin, of them only 12 (46%) achieved desired level of glycemic control. Most women with GDM achieved desired level of glycemic control under glyburide treatment.

Identifying demographic variables related to failed dental appointments in a university hospital-based residency program.

PubMed

Mathu-Muju, Kavita R; Li, Hsin-Fang; Hicks, James; Nash, David A; Kaplan, Alan; Bush, Heather M

2014-01-01

The objective of this study was to identify characteristics of pediatric patients who failed to keep the majority of their scheduled dental appointments in a pediatric dental clinic staffed by pediatric dental residents and faculty members. The electronic records of all patients appointed over a continuous 54 month period were analyzed. Appointment history and demographic variables were collected. The rate of failed appointments was calculated by dividing the number of failed appointments with the total number of appointments scheduled for the patient. There were 7,591 patients in the analyzable dataset scheduled with a total of 48,932 appointments. Factors associated with an increased rate of failed appointments included self-paying for dental care, having a resident versus a faculty member as the provider, rural residence, and adolescent aged patients. Multivariable regression models indicated self-paying patients had higher odds and rates of failed appointments than patients with Medicaid and private insurance. Access to care for children may be improved by increasing the availability of private and public insurance. The establishment of a dental home and its relationship to a child receiving continuous care in an institutional setting depends upon establishing a relationship with a specific dentist.

Control of Atherosclerosis Regression by PRMT2 in Diabetes

DTIC Science & Technology

2017-08-01

AWARD NUMBER: W81XWH-16-1-0373 TITLE: Control of Atherosclerosis Regression by PRMT2 in Diabetes PRINCIPAL INVESTIGATOR: Michael Garabedian...failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO...THE ABOVE ADDRESS. 1. REPORT DATE August 2017 2. REPORT TYPE Annual 3. DATES COVERED 1 Aug 2016 - 31 Jul 2017 4. TITLE AND SUBTITLE Control of

Assessing the dependence of sensitivity and specificity on prevalence in meta-analysis

PubMed Central

Li, Jialiang; Fine, Jason P.

2011-01-01

We consider modeling the dependence of sensitivity and specificity on the disease prevalence in diagnostic accuracy studies. Many meta-analyses compare test accuracy across studies and fail to incorporate the possible connection between the accuracy measures and the prevalence. We propose a Pearson type correlation coefficient and an estimating equation–based regression framework to help understand such a practical dependence. The results we derive may then be used to better interpret the results from meta-analyses. In the biomedical examples analyzed in this paper, the diagnostic accuracy of biomarkers are shown to be associated with prevalence, providing insights into the utility of these biomarkers in low- and high-prevalence populations. PMID:21525421

Predicting academic performance in surgical training.

PubMed

Yost, Michael J; Gardner, Jeffery; Bell, Richard McMurtry; Fann, Stephen A; Lisk, John R; Cheadle, William G; Goldman, Mitchell H; Rawn, Susan; Weigelt, John A; Termuhlen, Paula M; Woods, Randy J; Endean, Erick D; Kimbrough, Joy; Hulme, Michael

2015-01-01

During surgical residency, trainees are expected to master all the 6 competencies specified by the ACGME. Surgical training programs are also evaluated, in part, by the residency review committee based on the percentage of graduates of the program who successfully complete the qualifying examination and the certification examination of the American Board of Surgery in the first attempt. Many program directors (PDs) use the American Board of Surgery In-Training Examination (ABSITE) as an indicator of future performance on the qualifying examination. Failure to meet an individual program's standard may result in remediation or a delay in promotion to the next level of training. Remediation is expensive in terms of not only dollars but also resources, faculty time, and potential program disruptions. We embarked on an exploratory study to determine if residents who might be at risk for substandard performance on the ABSITE could be identified based on the individual resident's behavior and motivational characteristics. If such were possible, then PDs would have the opportunity to be proactive in developing a curriculum tailored to an individual resident, providing a greater opportunity for success in meeting the program's standards. Overall, 7 surgical training programs agreed to participate in this initial study and residents were recruited to voluntarily participate. Each participant completed an online assessment that characterizes an individual's behavioral style, motivators, and Acumen Index. Residents completed the assessment using a code name assigned by each individual PD or their designee. Assessments and the residents' 2013 ABSITE scores were forwarded for analysis using only the code name, thus insuring anonymity. Residents were grouped into those who took the junior examination, senior examination, and pass/fail categories. A passing score of ≥70% correct was chosen a priori. Correlations were performed using logistic regression and data were also entered into a neural network (NN) to develop a model that would explain performance based on data obtained from the TriMetrix assessments. A total of 117 residents' TriMetrix and ABSITE scores were available for analysis. They were divided into 2 groups of 64 senior residents and 53 junior residents. For each group, the pass/fail criteria for the ABSITE were set at 70 and greater as passing and 69 and lower as failing. Multiple logistic regression analysis was complete for pass/fail vs the TriMetrix assessments. For the senior data group, it was found that the parameter Theoretical correlates with pass rate (p < 0.043, B = -0.513, exp(B) = 0.599), which means increasing theoretical scores yields a decreasing likelihood of passing in the examination. For the junior data, the parameter Internal Role Awareness correlated with pass/fail rate (p < 0.004, B = 0.66, exp(B) = 1.935), which means that an increasing Internal Role Awareness score increases the likelihood of a passing score. The NN was able to be trained to predict ABSITE performance with surprising accuracy for both junior and senior residents. Behavioral, motivational, and acumen characteristics can be useful to identify residents "at risk" for substandard performance on the ABSITE. Armed with this information, PDs have the opportunity to intervene proactively to offer these residents a greater chance for success. The NN was capable of developing a model that explained performance on the examination for both the junior and the senior examinations. Subsequent testing is needed to determine if the NN is a good predictive tool for performance on this examination. Copyright © 2015 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

Empirical models based on the universal soil loss equation fail to predict sediment discharges from Chesapeake Bay catchments.

PubMed

Boomer, Kathleen B; Weller, Donald E; Jordan, Thomas E

2008-01-01

The Universal Soil Loss Equation (USLE) and its derivatives are widely used for identifying watersheds with a high potential for degrading stream water quality. We compared sediment yields estimated from regional application of the USLE, the automated revised RUSLE2, and five sediment delivery ratio algorithms to measured annual average sediment delivery in 78 catchments of the Chesapeake Bay watershed. We did the same comparisons for another 23 catchments monitored by the USGS. Predictions exceeded observed sediment yields by more than 100% and were highly correlated with USLE erosion predictions (Pearson r range, 0.73-0.92; p < 0.001). RUSLE2-erosion estimates were highly correlated with USLE estimates (r = 0.87; p < 001), so the method of implementing the USLE model did not change the results. In ranked comparisons between observed and predicted sediment yields, the models failed to identify catchments with higher yields (r range, -0.28-0.00; p > 0.14). In a multiple regression analysis, soil erodibility, log (stream flow), basin shape (topographic relief ratio), the square-root transformed proportion of forest, and occurrence in the Appalachian Plateau province explained 55% of the observed variance in measured suspended sediment loads, but the model performed poorly (r(2) = 0.06) at predicting loads in the 23 USGS watersheds not used in fitting the model. The use of USLE or multiple regression models to predict sediment yields is not advisable despite their present widespread application. Integrated watershed models based on the USLE may also be unsuitable for making management decisions.

Control of Atherosclerosis Regression by PRMT2 in Diabetes

DTIC Science & Technology

2017-08-01

AWARD NUMBER: W81XWH-16-1-0374 TITLE: Control of Atherosclerosis Regression by PRMT2 in Diabetes PRINCIPAL INVESTIGATOR: Edward Fisher, MD, PhD...for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM...TO THE ABOVE ADDRESS. 1. REPORT DATE August 2017 2. REPORT TYPE Annual 3. DATES COVERED 01 Aug 2016- 31-July 2017 4. TITLE AND SUBTITLE Control of

Is It safe? Nonoperative management of blunt splenic injuries in geriatric trauma patients.

PubMed

Trust, Marc D; Teixeira, Pedro G; Brown, Lawrence H; Ali, Sadia; Coopwood, Ben; Aydelotte, Jayson D; Brown, Carlos V R

2018-01-01

Because of increased failure rates of nonoperative management (NOM) of blunt splenic injuries (BSI) in the geriatric population, dogma dictated that this management was unacceptable. Recently, there has been an increased use of this treatment strategy in the geriatric population. However, published data assessing the safety of NOM of BSI in this population is conflicting, and well-powered multicenter data are lacking. We performed a retrospective analysis of data from the National Trauma Data Bank (NTDB) from 2014 and identified young (age < 65) and geriatric (age ≥ 65) patients with a BSI. Patients who underwent splenectomy within 6 hours of admission were excluded from the analysis. Outcomes were failure of NOM and mortality. We identified 18,917 total patients with a BSI, 2,240 (12%) geriatric patients and 16,677 (88%) young patients. Geriatric patients failed NOM more often than younger patients (6% vs. 4%, p < 0.0001). On logistic regression analysis, Injury Severity Score of 16 or higher was the only independent risk factor associated with failure of NOM in geriatric patients (odds ratio, 2.778; confidence interval, 1.769-4.363; p < 0.0001). There was no difference in mortality in geriatric patients who had successful vs. failed NOM (11% vs. 15%; p = 0.22). Independent risk factors for mortality in geriatric patients included admission hypotension, Injury Severity Score of 16 or higher, Glasgow Coma Scale score of 8 or less, and cardiac disease. However, failure of NOM was not independently associated with mortality (odds ratio, 1.429; confidence interval, 0.776-2.625; p = 0.25). Compared with younger patients, geriatric patients had a higher but comparable rate of failed NOM of BSI, and failure rates are lower than previously reported. Failure of NOM in geriatric patients is not an independent risk factor for mortality. Based on our results, NOM of BSI in geriatric patients is safe. Therapeutic, level IV.

Determining the response of sea level to atmospheric pressure forcing using TOPEX/POSEIDON data

NASA Technical Reports Server (NTRS)

Fu, Lee-Lueng; Pihos, Greg

1994-01-01

The static response of sea level to the forcing of atmospheric pressure, the so-called inverted barometer (IB) effect, is investigated using TOPEX/POSEIDON data. This response, characterized by the rise and fall of sea level to compensate for the change of atmospheric pressure at a rate of -1 cm/mbar, is not associated with any ocean currents and hence is normally treated as an error to be removed from sea level observation. Linear regression and spectral transfer function analyses are applied to sea level and pressure to examine the validity of the IB effect. In regions outside the tropics, the regression coefficient is found to be consistently close to the theoretical value except for the regions of western boundary currents, where the mesoscale variability interferes with the IB effect. The spectral transfer function shows near IB response at periods of 30 degrees is -0.84 +/- 0.29 cm/mbar (1 standard deviation). The deviation from = 1 cm /mbar is shown to be caused primarily by the effect of wind forcing on sea level, based on multivariate linear regression model involving both pressure and wind forcing. The regression coefficient for pressure resulting from the multivariate analysis is -0.96 +/- 0.32 cm/mbar. In the tropics the multivariate analysis fails because sea level in the tropics is primarily responding to remote wind forcing. However, after removing from the data the wind-forced sea level estimated by a dynamic model of the tropical Pacific, the pressure regression coefficient improves from -1.22 +/- 0.69 cm/mbar to -0.99 +/- 0.46 cm/mbar, clearly revealing an IB response. The result of the study suggests that with a proper removal of the effect of wind forcing the IB effect is valid in most of the open ocean at periods longer than 20 days and spatial scales larger than 500 km.

Assessing Spurious Interaction Effects in Structural Equation Modeling

ERIC Educational Resources Information Center

Harring, Jeffrey R.; Weiss, Brandi A.; Li, Ming

2015-01-01

Several studies have stressed the importance of simultaneously estimating interaction and quadratic effects in multiple regression analyses, even if theory only suggests an interaction effect should be present. Specifically, past studies suggested that failing to simultaneously include quadratic effects when testing for interaction effects could…

A general framework for the regression analysis of pooled biomarker assessments.

PubMed

Liu, Yan; McMahan, Christopher; Gallagher, Colin

2017-07-10

As a cost-efficient data collection mechanism, the process of assaying pooled biospecimens is becoming increasingly common in epidemiological research; for example, pooling has been proposed for the purpose of evaluating the diagnostic efficacy of biological markers (biomarkers). To this end, several authors have proposed techniques that allow for the analysis of continuous pooled biomarker assessments. Regretfully, most of these techniques proceed under restrictive assumptions, are unable to account for the effects of measurement error, and fail to control for confounding variables. These limitations are understandably attributable to the complex structure that is inherent to measurements taken on pooled specimens. Consequently, in order to provide practitioners with the tools necessary to accurately and efficiently analyze pooled biomarker assessments, herein, a general Monte Carlo maximum likelihood-based procedure is presented. The proposed approach allows for the regression analysis of pooled data under practically all parametric models and can be used to directly account for the effects of measurement error. Through simulation, it is shown that the proposed approach can accurately and efficiently estimate all unknown parameters and is more computational efficient than existing techniques. This new methodology is further illustrated using monocyte chemotactic protein-1 data collected by the Collaborative Perinatal Project in an effort to assess the relationship between this chemokine and the risk of miscarriage. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Service and sales workers, are they vulnerable to smoking cessation?

PubMed

Cho, Youn-Mo; Myong, Jun-Pyo; Kim, Hyoung-Ryoul; Lee, HyeEun; Koo, Jung-Wan

2017-10-07

The aim of the present study was to evaluate the association between failed smoking cessation and occupation by age stratification among Korean males and provide quantitative evidence of factors associated with failed smoking cessation. The study comprised 3,127 male workers who had attempted smoking cessation during their life time. Data were obtained from the Korea National Health and Nutrition Examination Survey from 2010 to 2012. Participants were stratified by age into two subgroups comprising a younger group (19-40 yr) and an older group (41-60 yr). Multiple logistic regression analyses were used to estimate odds ratios (ORs) for failed smoking cessation. In the younger group, failed smoking cessation was related to the occupational fields "service and sales" and "manual work" compared to "office work" (OR: 2.10, 95% confidence interval (CI): 1.34-3.29; and OR: 1.47, 95% CI: 1.02-2.12, respectively). In the older group, the ORs of failed smoking cessation occupational categories "service and sales" and "manual work" [ref: office workers] were 0.58 (0.40-0.85) and 0.90 (0.66-1.24), respectively. Failed smoking cessation is associated with occupational categories and age stratification. Policy makers need to create tailored anti-smoking policy considering the occupation and the age of the subjects.

Molecular Changes in Children with Heart Failure Undergoing Left Ventricular Assist Device Therapy.

PubMed

Medina, Elizabeth; Sucharov, Carmen C; Nelson, Penny; Miyamoto, Shelley D; Stauffer, Brian L

2017-03-01

To determine whether left ventricular assist device (LVAD) treatment in children with heart failure would result in the modification of molecular pathways involved in heart failure pathophysiology. Forty-seven explanted hearts from children were studied (16 nonfailing control, 20 failing, and 11 failing post-LVAD implantation [F-LVAD]). Protein expression and phosphorylation states were determined by receptor binding assays and Western blots. mRNA expression was measured with real-time quantitative polymerase chain reaction. To evaluate for interactions and identify correlations, 2-way ANOVA and regression analysis were performed. Treatment with LVAD resulted in recovery of total β-adrenergic receptor expression and β 1 -adrenergic receptor (β 1 -AR) in failing hearts to normal levels (β-adrenergic receptor expression : 67.2 ± 11.5 fmol/mg failing vs 99.5 ± 27.7 fmol/mg nonfailing, 104 ± 38.7 fmol/mg F-LVAD, P ≤ .01; β 1 -AR: 52.2 ± 10.3 fmol/mg failing vs 83.0 ± 23 fmol/mg non-failing, 76.5 ± 32.1 fmol/mg F-LVAD P ≤ .03). The high levels of G protein-coupled receptor kinase-2 were returned to nonfailing levels after LVAD treatment (5.6 ± 9.0 failing vs 1.0 ± 0.493 nonfailing, 1.0 ± 1.3 F-LVAD). Interestingly, β 2 -adrenergic receptor expression was significantly greater in F-LVAD (27.5 ± 12; P < .005) hearts compared with nonfailing (16.4 ± 6.1) and failing (15.1 ± 4.2) hearts. Phospholamban phosphorylation at serine 16 was significantly greater in F-LVAD (7.7 ± 11.7) hearts compared with nonfailing (1.0 ± 1.2, P = .02) and failing (0.8 ± 1.0, P = .01) hearts. Also, atrial natriuretic factor (0.6 ± 0.8) and brain natriuretic peptide (0.1 ± 0.1) expression in F-LVAD was significantly lower compared with failing hearts (2.8 ± 3.6, P = .01 and 0.6 ± 0.7, P = .02). LVAD treatment in children with heart failure results in reversal of several pathologic myocellular processes, and G protein-coupled receptor kinase-2 may regulate β 1 -AR but not β 2 -adrenergic receptor expression in children with heart failure. Copyright © 2016 Elsevier Inc. All rights reserved.

Determinants of single family residential water use across scales in four western US cities.

PubMed

Chang, Heejun; Bonnette, Matthew Ryan; Stoker, Philip; Crow-Miller, Britt; Wentz, Elizabeth

2017-10-15

A growing body of literature examines urban water sustainability with increasing evidence that locally-based physical and social spatial interactions contribute to water use. These studies however are based on single-city analysis and often fail to consider whether these interactions occur more generally. We examine a multi-city comparison using a common set of spatially-explicit water, socioeconomic, and biophysical data. We investigate the relative importance of variables for explaining the variations of single family residential (SFR) water uses at Census Block Group (CBG) and Census Tract (CT) scales in four representative western US cities - Austin, Phoenix, Portland, and Salt Lake City, - which cover a wide range of climate and development density. We used both ordinary least squares regression and spatial error regression models to identify the influence of spatial dependence on water use patterns. Our results show that older downtown areas show lower water use than newer suburban areas in all four cities. Tax assessed value and building age are the main determinants of SFR water use across the four cities regardless of the scale. Impervious surface area becomes an important variable for summer water use in all cities, and it is important in all seasons for arid environments such as Phoenix. CT level analysis shows better model predictability than CBG analysis. In all cities, seasons, and spatial scales, spatial error regression models better explain the variations of SFR water use. Such a spatially-varying relationship of urban water consumption provides additional evidence for the need to integrate urban land use planning and municipal water planning. Copyright © 2017 Elsevier B.V. All rights reserved.

When and why a colonoscopist should discontinue colonoscopy by himself?

PubMed

Gan, Tao; Yang, Jin-Lin; Wu, Jun-Chao; Wang, Yi-Ping; Yang, Li

2015-07-07

To investigate when and why a colonoscopist should discontinue incomplete colonoscopy by himself. In this cross-sectional study, 517 difficult colonoscope insertions (Grade C, Kudo's difficulty classification) screened from 37800 colonoscopy insertions were collected from April 2004 to June 2014 by three 4(th)-level (Kudo's classification) colonoscopists. The following common factors for the incomplete insertion were excluded: structural obstruction of the colon or rectum, insufficient colon cleansing, discontinuation due to patient's discomfort or pain, severe colon disease with a perforation risk (e.g., severe ischemic colonopathy). All the excluded patients were re-scheduled if permission was obtained from the patients whose intubation had failed. If the repeat intubations were still a failure because of the difficult operative techniques, those patients were also included in this study. The patient's age, sex, anesthesia and colonoscope type were recorded before colonoscopy. During the colonoscopic examination, the influencing factors of fixation, tortuosity, laxity and redundancy of the colon were assessed, and the insertion time (> 10 min or ≤ 10 min) were registered. The insertion time was analyzed by t-test, and other factors were analyzed by univariate and multivariate logistic regression. Three hundred and twenty-two (62.3%) of the 517 insertions were complete in the colonoscope insertion into the ileocecum, but 195 (37.7%) failed in the insertion. Fixation, tortuosity, laxity or redundancy occurred during the colonoscopic examination. Multivariate logistic regression analysis revealed that fixation (OR = 0.06, 95%CI: 0.03-0.16, P < 0.001) and tortuosity (OR = 0.04, 95%CI: 0.02-0.08, P < 0.001) were significantly related to the insertion into the ileocecum in the left hemicolon; multivariate logistic regression analysis also revealed that fixation (OR = 0.16, 95%CI: 0.06-0.39, P < 0.001), tortuosity (OR 0.23, 95%CI: 0.13-0.43, P < 0.001), redundancy (OR = 0.12, 95%CI: 0.05-0.26, P < 0.001) and sex (OR = 0.35, 95%CI: 0.20-0.63, P < 0.001) were significantly related to the insertion into the ileocecum in the right hemicolon. Prolonged insertion time (> 10 min) was an unfavorable factor for the insertion into the ileocecum. Colonoscopy should be discontinued if freedom of the colonoscope body's insertion and rotation is completely lost, and the insertion time is prolonged over 30 min.

SDN solutions for switching dedicated long-haul connections: Measurements and comparative analysis

DOE PAGES

Rao, Nageswara S. V.

2016-01-01

We consider a scenario of two sites connected over a dedicated, long-haul connection that must quickly fail-over in response to degradations in host-to-host application performance. The traditional layer-2/3 hot stand-by fail-over solutions do not adequately address the variety of application degradations, and more recent single controller Software Defined Networks (SDN) solutions are not effective for long-haul connections. We present two methods for such a path fail-over using OpenFlow enabled switches: (a) a light-weight method that utilizes host scripts to monitor application performance and dpctl API for switching, and (b) a generic method that uses two OpenDaylight (ODL) controllers and RESTmore » interfaces. For both methods, the restoration dynamics of applications contain significant statistical variations due to the complexities of controllers, north bound interfaces and switches; they, together with the wide variety of vendor implementations, complicate the choice among such solutions. We develop the impulse-response method based on regression functions of performance parameters to provide a rigorous and objective comparison of different solutions. We describe testing results of the two proposed methods, using TCP throughput and connection rtt as main parameters, over a testbed consisting of HP and Cisco switches connected over longhaul connections emulated in hardware by ANUE devices. Lastly, the combination of analytical and experimental results demonstrate that the dpctl method responds seconds faster than the ODL method on average, even though both methods eventually restore original TCP throughput.« less

B cells are critical to T-cell-mediated antitumor immunity induced by a combined immune-stimulatory/conditionally cytotoxic therapy for glioblastoma.

PubMed

Candolfi, Marianela; Curtin, James F; Yagiz, Kader; Assi, Hikmat; Wibowo, Mia K; Alzadeh, Gabrielle E; Foulad, David; Muhammad, A K M G; Salehi, Sofia; Keech, Naomi; Puntel, Mariana; Liu, Chunyan; Sanderson, Nicholas R; Kroeger, Kurt M; Dunn, Robert; Martins, Gislaine; Lowenstein, Pedro R; Castro, Maria G

2011-10-01

We have demonstrated that modifying the tumor microenvironment through intratumoral administration of adenoviral vectors (Ad) encoding the conditional cytotoxic molecule, i.e., HSV1-TK and the immune-stimulatory cytokine, i.e., fms-like tyrosine kinase 3 ligand (Flt3L) leads to T-cell-dependent tumor regression in rodent models of glioblastoma. We investigated the role of B cells during immune-mediated glioblastoma multiforme regression. Although treatment with Ad-TK+Ad-Flt3L induced tumor regression in 60% of wild-type (WT) mice, it completely failed in B-cell-deficient Igh6(-/-) mice. Tumor-specific T-cell precursors were detected in Ad-TK+Ad-Flt3L-treated WT mice but not in Igh6(-/-) mice. The treatment also failed in WT mice depleted of total B cells or marginal zone B cells. Because we could not detect circulating antibodies against tumor cells and the treatment was equally efficient in WT mice and in mice with B-cell-specific deletion of Prdm 1 (encoding Blimp-1), in which B cells are present but unable to fully differentiate into antibody-secreting plasma cells, tumor regression in this model is not dependent on B cells' production of tumor antigen-specific immunoglobulins. Instead, B cells seem to play a role as antigen-presenting cells (APCs). Treatment with Ad-TK+Ad-Flt3L led to an increase in the number of B cells in the cervical lymph nodes, which stimulated the proliferation of syngeneic T cells and induced clonal expansion of antitumor T cells. Our data show that B cells act as APCs, playing a critical role in clonal expansion of tumor antigen-specific T cells and brain tumor regression.

Predictors of survival among hemodialysis patients: effect of perceived family support.

PubMed

Christensen, A J; Wiebe, J S; Smith, T W; Turner, C W

1994-11-01

The authors examined the role of perceived family support and symptoms of depression as predictors of survival in a sample of 78 in-center hemodialysis patients. Cox regression analysis revealed significant effects for family support (p < .005), blood urea nitrogen (p < .01), and age (p < .005). The effect for depression was not significant. The Cox model indicated that a 1-point increase on the family support measure was associated with a 13% reduction in the hazard rate (i.e., mortality). Estimated 5-year mortality rates among low family support patients were approximately 3 times higher than estimated mortality for high support patients. Differences in patient adherence to the dietary and medication regimens failed to explain the significant effect of family support.

Admixture Analysis of Spontaneous Hepatitis C Virus Clearance in Individuals of African-Descent

PubMed Central

Wojcik, Genevieve L.; Thio, Chloe L.; Kao, WH Linda; Latanich, Rachel; Goedert, James J.; Mehta, Shruti H.; Kirk, Gregory D.; Peters, Marion G.; Cox, Andrea L.; Kim, Arthur Y.; Chung, Raymond T.; Thomas, David L.; Duggal, Priya

2015-01-01

Hepatitis C virus (HCV) infects an estimated 3% of the global population with the majority of individuals (75–85%) failing to clear the virus without treatment, leading to chronic liver disease. Individuals of African-descent have lower rates of clearance compared to individuals of European-descent and this is not fully explained by social and environmental factors. This suggests that differences in genetic background may contribute to this difference in clinical outcome following HCV infection. Using 473 individuals and 792,721 SNPs from a genome-wide association study (GWAS), we estimated local African ancestry across the genome. Using admixture mapping and logistic regression we identified two regions of interest associated with spontaneous clearance of HCV (15q24, 20p12). A genome-wide significant variant was identified on chromosome 15 at the imputed SNP, rs55817928 (P=6.18×10−8) between the genes SCAPER and RCN. Each additional copy of the African ancestral C allele is associated with 2.4 times the odds of spontaneous clearance. Conditional analysis using this SNP in the logistic regression model explained one-third of the local ancestry association. Additionally, signals of selection in this area suggest positive selection due to some ancestral pathogen or environmental pressure in African, but not in European populations. PMID:24622687

An analysis of hearing screening test results in 2291 premature infants of Chinese population.

PubMed

Huang, Lili; Xiong, Fei; Li, Jinrong; Yang, Fan

2017-04-01

The aim of this study was to analyze the hearing screening program among preterm infants as well as to identify risk factors associated with failing primary newborn hearing screening. The retrospectively selected population included all preterm infants who had primary hearing screening in a neonatal ward from January 1st, 2013 to December 31st, 2015 at West China Second University Hospital, Sichuan University. The newborn hearing screening (NHS) procedure was performed in all preterm infants by automated auditory brainstem response (AABR). Infants who failed the primary hearing screening received a second screening at 42 days after birth. Infants who failed both tests were referred to a tertiary audiology center for diagnostic confirmation and management before 6 months of age. The final diagnosis for referred infants was obtained by telephone follow-up. The risk factors associated with failure to pass the primary hearing screen were evaluated and analyzed for preterm infants. Among 2291 preterm infants recruited, 155 infants (6.8%) failed the primary hearing screening with an abnormal AABR. Of these 155 infants, 113 (72.9%) passed the secondary screening. At the end of the follow-up, 1 infant (0.04%) was diagnosed with hearing loss, 3 infants had delayed language development, and 40 infants were lost to follow up. Multivariate regression analysis revealed that gestational age ≤32 weeks (Odds ratio [OR] = 2.093, 95% confidence interval [CI] 1.370-3.196), super hyperbilirubinemia (≥25 mg/dl) (OR = 3.560, 95% CI 1.009-12.560), and respiratory failure (OR = 1.971, 95% CI 1.188-3.265) were associated with failure to pass newborn hearing screening. The prevalence of failure to pass primary hearing screening among preterm infants was 6.8% in our study, and we found a relatively low prevalence of hearing loss (0.04%). Super hyperbilirubinemia, gestational age ≤32weeks, and respiratory failure were risk factors associated with failure of preterm infants to pass the primary hearing screening. Our results suggest that preterm infants with hyperbilirubinemia, gestational age ≤32 weeks, and respiratory failure should be closely followed. Copyright © 2017 Elsevier B.V. All rights reserved.

Developing Empirical Lightning Cessation Forecast Guidance for the Cape Canaveral Air Force Station and Kennedy Space Center

NASA Technical Reports Server (NTRS)

Stano, Geoffrey T.; Fuelberg, Henry E.; Roeder, William P.

2010-01-01

This research addresses the 45th Weather Squadron's (45WS) need for improved guidance regarding lightning cessation at Cape Canaveral Air Force Station and Kennedy Space Center (KSC). KSC's Lightning Detection and Ranging (LDAR) network was the primary observational tool to investigate both cloud-to-ground and intracloud lightning. Five statistical and empirical schemes were created from LDAR, sounding, and radar parameters derived from 116 storms. Four of the five schemes were unsuitable for operational use since lightning advisories would be canceled prematurely, leading to safety risks to personnel. These include a correlation and regression tree analysis, three variants of multiple linear regression, event time trending, and the time delay between the greatest height of the maximum dBZ value to the last flash. These schemes failed to adequately forecast the maximum interval, the greatest time between any two flashes in the storm. The majority of storms had a maximum interval less than 10 min, which biased the schemes toward small values. Success was achieved with the percentile method (PM) by separating the maximum interval into percentiles for the 100 dependent storms.

Drop-Weight Impact Test on U-Shape Concrete Specimens with Statistical and Regression Analyses

PubMed Central

Zhu, Xue-Chao; Zhu, Han; Li, Hao-Ran

2015-01-01

According to the principle and method of drop-weight impact test, the impact resistance of concrete was measured using self-designed U-shape specimens and a newly designed drop-weight impact test apparatus. A series of drop-weight impact tests were carried out with four different masses of drop hammers (0.875, 0.8, 0.675 and 0.5 kg). The test results show that the impact resistance results fail to follow a normal distribution. As expected, U-shaped specimens can predetermine the location of the cracks very well. It is also easy to record the cracks propagation during the test. The maximum of coefficient of variation in this study is 31.2%; it is lower than the values obtained from the American Concrete Institute (ACI) impact tests in the literature. By regression analysis, the linear relationship between the first-crack and ultimate failure impact resistance is good. It can suggested that a minimum number of specimens is required to reliably measure the properties of the material based on the observed levels of variation. PMID:28793540

Significant Factors Related to Failed Pediatric Dental General Anesthesia Appointments at a Hospital-based Residency Program.

PubMed

Emhardt, John R; Yepes, Juan F; Vinson, LaQuia A; Jones, James E; Emhardt, John D; Kozlowski, Diana C; Eckert, George J; Maupome, Gerardo

2017-05-15

The purposes of this study were to: (1) evaluate the relationship between appointment failure and the factors of age, gender, race, insurance type, day of week, scheduled time of surgery, distance traveled, and weather; (2) investigate reasons for failure; and (3) explore the relationships between the factors and reasons for failure. Electronic medical records were accessed to obtain data for patients scheduled for dental care under general anesthesia from May 2012 to May 2015. Factors were analyzed for relation to appointment failure. Data from 3,513 appointments for 2,874 children were analyzed. Bivariate associations showed statistically significant (P<0.05) relationships between failed appointment and race, insurance type, scheduled time of surgery, distance traveled, snowfall, and temperature. Multinomial regression analysis showed the following associations between factors and the reason for failure (P<0.05): (1) decreased temperature and increased snowfall were associated with weather as reason for failure; (2) the African American population showed an association with family barriers; (3) Hispanic families were less likely to give advanced notice; and (4) the "additional races" category showed an association with fasting violation. Patients who have treatment under general anesthesia face specific barriers to care.

An Alternative Method for Allocating Base Maintenance Supplies to Mission, Design, and Series Aircraft in the United States Air Force.

DTIC Science & Technology

1987-09-01

Edition,. Fail 1986. 33. Neter, John et al. Applied Linear Regression MoceL. Homewood IL: Richard D. Irwin, Incorporated, iJ83. 34. NovicK, David... Linear Regression Models (33) then, for each sample observation (X fh, the method of least squares considers the deviation of Yubms from its expected value...for finding good estimators of b - b5 * In -2raer to explain the procedure, the model Yubms = b0 + b!xfh will be discussed. According to Applied

CD4+ T-cells Contribute to the Remodeling of the Microenvironment Required for Sustained Tumor Regression upon Oncogene Inactivation

PubMed Central

Rakhra, Kavya; Bachireddy, Pavan; Zabuawala, Tahera; Zeiser, Robert; Xu, Liwen; Kopelman, Andrew; Fan, Alice C.; Yang, Qiwei; Braunstein, Lior; Crosby, Erika; Ryeom, Sandra; Felsher, Dean W.

2010-01-01

Summary Oncogene addiction is thought to occur cell autonomously. Immune effectors are implicated in the induction and restraint of tumorigenesis, but their role in oncogene inactivation mediated tumor regression is unclear. Here, we show that an intact immune system, specifically CD4+ T-cells, is required for the induction of cellular senescence, shut down of angiogenesis and chemokine expression resulting in sustained tumor regression upon inactivation of the MYC or BCR-ABL oncogenes in mouse models of T-cell acute lymphoblastic lymphoma and pro-B-cell leukemia, respectively. Moreover, immune effectors knocked out for thrombospondins failed to induce sustained tumor regression. Hence, CD4+ T-cells are required for the remodeling of the tumor microenvironment through the expression of chemokines, such as thrombospondins, in order to elicit oncogene addiction. PMID:21035406

Presenting hydrothorax predicts failure of needle aspiration in primary spontaneous pneumothorax.

PubMed

Wu, Kwok Kei; Lui, Chun Tat; Ho, Chik Leung; Tsui, Kwok Leung; Fung, Hin Tat

2016-06-01

The objective was to evaluate if existence of hydrothorax in initial chest radiograph predicts treatment outcome in patients with primary spontaneous pneumothorax who received needle thoracostomy. This is a retrospective cohort study carried out from January 2011 to August 2014 in 1 public hospital in Hong Kong. All consecutive adult patients aged 18years or above who attended the emergency department with the diagnosis of primary spontaneous pneumothorax with needle aspiration performed as primary treatment were included. Age, smoking status, size of pneumothorax, previous history of pneumothorax, aspirated gas volume and presence of hydropneumothorax in initial radiograph were included in the analysis. The outcome was success or failure of the needle aspiration. Logistic regression was used to identify the predicting factors of failure of needle aspiration. There were a total of 127 patients included. Seventy-three patients (57.5%) were successfully treated with no recurrence upon discharge. Among 54 failure cases, 13 patients (10.2%) failed immediately after procedure as evident by chest radiograph and required second treatment. Forty-one patients (32.3%) failed upon subsequent chest radiographs. Multivariate logistic regression showed factors independently associated with the failure of needle aspiration, which included hydropneumothorax in the initial radiograph (odds ratio [OR]=4.47 [1.56i12.83], P=.005), previous history of pneumothorax (OR=3.92 [1.57-9.79], P=.003), and large size of pneumothorax defined as apex-to-cupola distance ≥5cm (OR=2.75 [1.21-6.26], P=.016). Hydropneumothorax, previous history of pneumothorax, and large size were independent predictors of failure of needle aspiration in treatment of primary spontaneous pneumothorax. Copyright © 2016 Elsevier Inc. All rights reserved.

Variable Selection through Correlation Sifting

NASA Astrophysics Data System (ADS)

Huang, Jim C.; Jojic, Nebojsa

Many applications of computational biology require a variable selection procedure to sift through a large number of input variables and select some smaller number that influence a target variable of interest. For example, in virology, only some small number of viral protein fragments influence the nature of the immune response during viral infection. Due to the large number of variables to be considered, a brute-force search for the subset of variables is in general intractable. To approximate this, methods based on ℓ1-regularized linear regression have been proposed and have been found to be particularly successful. It is well understood however that such methods fail to choose the correct subset of variables if these are highly correlated with other "decoy" variables. We present a method for sifting through sets of highly correlated variables which leads to higher accuracy in selecting the correct variables. The main innovation is a filtering step that reduces correlations among variables to be selected, making the ℓ1-regularization effective for datasets on which many methods for variable selection fail. The filtering step changes both the values of the predictor variables and output values by projections onto components obtained through a computationally-inexpensive principal components analysis. In this paper we demonstrate the usefulness of our method on synthetic datasets and on novel applications in virology. These include HIV viral load analysis based on patients' HIV sequences and immune types, as well as the analysis of seasonal variation in influenza death rates based on the regions of the influenza genome that undergo diversifying selection in the previous season.

Vocal mechanics in Darwin's finches: correlation of beak gape and song frequency.

PubMed

Podos, Jeffrey; Southall, Joel A; Rossi-Santos, Marcos R

2004-02-01

Recent studies of vocal mechanics in songbirds have identified a functional role for the beak in sound production. The vocal tract (trachea and beak) filters harmonic overtones from sounds produced by the syrinx, and birds can fine-tune vocal tract resonance properties through changes in beak gape. In this study, we examine patterns of beak gape during song production in seven species of Darwin's finches of the Galápagos Islands. Our principal goals were to characterize the relationship between beak gape and vocal frequency during song production and to explore the possible influence therein of diversity in beak morphology and body size. Birds were audio and video recorded (at 30 frames s(-1)) as they sang in the field, and 164 song sequences were analyzed. We found that song frequency regressed significantly and positively on beak gape for 38 of 56 individuals and for all seven species examined. This finding provides broad support for a resonance model of vocal tract function in Darwin's finches. Comparison among species revealed significant variation in regression y-intercept values. Body size correlated negatively with y-intercept values, although not at a statistically significant level. We failed to detect variation in regression slopes among finch species, although the regression slopes of Darwin's finch and two North American sparrow species were found to differ. Analysis within one species (Geospiza fortis) revealed significant inter-individual variation in regression parameters; these parameters did not correlate with song frequency features or plumage scores. Our results suggest that patterns of beak use during song production were conserved during the Darwin's finch adaptive radiation, despite the evolution of substantial variation in beak morphology and body size.

A regularization corrected score method for nonlinear regression models with covariate error.

PubMed

Zucker, David M; Gorfine, Malka; Li, Yi; Tadesse, Mahlet G; Spiegelman, Donna

2013-03-01

Many regression analyses involve explanatory variables that are measured with error, and failing to account for this error is well known to lead to biased point and interval estimates of the regression coefficients. We present here a new general method for adjusting for covariate error. Our method consists of an approximate version of the Stefanski-Nakamura corrected score approach, using the method of regularization to obtain an approximate solution of the relevant integral equation. We develop the theory in the setting of classical likelihood models; this setting covers, for example, linear regression, nonlinear regression, logistic regression, and Poisson regression. The method is extremely general in terms of the types of measurement error models covered, and is a functional method in the sense of not involving assumptions on the distribution of the true covariate. We discuss the theoretical properties of the method and present simulation results in the logistic regression setting (univariate and multivariate). For illustration, we apply the method to data from the Harvard Nurses' Health Study concerning the relationship between physical activity and breast cancer mortality in the period following a diagnosis of breast cancer. Copyright © 2013, The International Biometric Society.

Evaluating Federal Information Technology Program Success Based on Earned Value Management

ERIC Educational Resources Information Center

Moy, Mae N.

2016-01-01

Despite the use of earned value management (EVM) techniques to track development progress, federal information (IT) software programs continue to fail by not meeting identified business requirements. The purpose of this logistic regression study was to examine, using IT software data from federal agencies from 2011 to 2014, whether a relationship…

Simulation-Extrapolation for Estimating Means and Causal Effects with Mismeasured Covariates

ERIC Educational Resources Information Center

Lockwood, J. R.; McCaffrey, Daniel F.

2015-01-01

Regression, weighting and related approaches to estimating a population mean from a sample with nonrandom missing data often rely on the assumption that conditional on covariates, observed samples can be treated as random. Standard methods using this assumption generally will fail to yield consistent estimators when covariates are measured with…

Career Management and the Changing Psychological Contract.

ERIC Educational Resources Information Center

Atkinson, Carol

2002-01-01

A 1993 survey in a British bank revealed a lack of strategic approaches to career management and a negative psychological contract. A 2000 follow-up showed that employees viewed the new contract as a regression from a relational to a transactional approach. They had increased responsibility for career development, but management failed to provide…

A National Cohort Study of U.S. Medical School Students Who Initially Failed Step 1 of the United States Medical Licensing Examination

PubMed Central

Andriole, Dorothy A.; Jeffe, Donna B.

2012-01-01

Purpose To describe educational outcomes for a national cohort of U.S. medical students who initially failed Step 1 of the United States Medical Licensing Examination Method The authors analyzed de-identified, individualized records for the 1993–2000 cohort of U.S. medical school matriculants who both initially failed Step l and were no longer in medical school as of March 2, 2009, using multivariable logistic regression to identify factors associated with attempting, and initially passing, Step 2 Clinical Knowledge (CK). Results Of 6,594 students who failed Step l, 5,985 (90.8%) took Step 2CK. Women and Asian/Pacific Islander students were more likely to attempt Step 2CK; more recent matriculants and students with lower failing Step 1 scores were less likely. Of the 5,985 students who attempted Step 2CK, 4,168 (69.6%) initially passed. Women, students with higher Medical College Admission Test scores, and more recent matriculants were more likely to pass Step 2CK; Asian/Pacific Islander students, underrepresented minority students, older students, and students with lower failing Step 1 scores were less likely. Ninety percent of students in the study sample (5,952/6,594) ultimately graduated from medical school, including 99.5% (4,148/4,168) of those who initially passed, 96.7% (1,757/1,817) of those who initially failed, and 7.7% (47/609) of those who never attempted Step 2CK. Conclusions The authors identified variables associated with educational outcomes among students who failed Step l. These findings can inform medical schools’ efforts to develop tailored interventions to maximize the likelihood that students will take Step 2CK and pass it on the first attempt. PMID:22361789

Enhancement of partial robust M-regression (PRM) performance using Bisquare weight function

NASA Astrophysics Data System (ADS)

Mohamad, Mazni; Ramli, Norazan Mohamed; Ghani@Mamat, Nor Azura Md; Ahmad, Sanizah

2014-09-01

Partial Least Squares (PLS) regression is a popular regression technique for handling multicollinearity in low and high dimensional data which fits a linear relationship between sets of explanatory and response variables. Several robust PLS methods are proposed to accommodate the classical PLS algorithms which are easily affected with the presence of outliers. The recent one was called partial robust M-regression (PRM). Unfortunately, the use of monotonous weighting function in the PRM algorithm fails to assign appropriate and proper weights to large outliers according to their severity. Thus, in this paper, a modified partial robust M-regression is introduced to enhance the performance of the original PRM. A re-descending weight function, known as Bisquare weight function is recommended to replace the fair function in the PRM. A simulation study is done to assess the performance of the modified PRM and its efficiency is also tested in both contaminated and uncontaminated simulated data under various percentages of outliers, sample sizes and number of predictors.

Steep discounting of delayed monetary and food rewards in obesity: a meta-analysis.

PubMed

Amlung, M; Petker, T; Jackson, J; Balodis, I; MacKillop, J

2016-08-01

An increasing number of studies have investigated delay discounting (DD) in relation to obesity, but with mixed findings. This meta-analysis synthesized the literature on the relationship between monetary and food DD and obesity, with three objectives: (1) to characterize the relationship between DD and obesity in both case-control comparisons and continuous designs; (2) to examine potential moderators, including case-control v. continuous design, money v. food rewards, sample sex distribution, and sample age (18 years); and (3) to evaluate publication bias. From 134 candidate articles, 39 independent investigations yielded 29 case-control and 30 continuous comparisons (total n = 10 278). Random-effects meta-analysis was conducted using Cohen's d as the effect size. Publication bias was evaluated using fail-safe N, Begg-Mazumdar and Egger tests, meta-regression of publication year and effect size, and imputation of missing studies. The primary analysis revealed a medium effect size across studies that was highly statistically significant (d = 0.43, p < 10-14). None of the moderators examined yielded statistically significant differences, although notably larger effect sizes were found for studies with case-control designs, food rewards and child/adolescent samples. Limited evidence of publication bias was present, although the Begg-Mazumdar test and meta-regression suggested a slightly diminishing effect size over time. Steep DD of food and money appears to be a robust feature of obesity that is relatively consistent across the DD assessment methodologies and study designs examined. These findings are discussed in the context of research on DD in drug addiction, the neural bases of DD in obesity, and potential clinical applications.

Rank-Optimized Logistic Matrix Regression toward Improved Matrix Data Classification.

PubMed

Zhang, Jianguang; Jiang, Jianmin

2018-02-01

While existing logistic regression suffers from overfitting and often fails in considering structural information, we propose a novel matrix-based logistic regression to overcome the weakness. In the proposed method, 2D matrices are directly used to learn two groups of parameter vectors along each dimension without vectorization, which allows the proposed method to fully exploit the underlying structural information embedded inside the 2D matrices. Further, we add a joint [Formula: see text]-norm on two parameter matrices, which are organized by aligning each group of parameter vectors in columns. This added co-regularization term has two roles-enhancing the effect of regularization and optimizing the rank during the learning process. With our proposed fast iterative solution, we carried out extensive experiments. The results show that in comparison to both the traditional tensor-based methods and the vector-based regression methods, our proposed solution achieves better performance for matrix data classifications.

Logistic Regression with Multiple Random Effects: A Simulation Study of Estimation Methods and Statistical Packages.

PubMed

Kim, Yoonsang; Choi, Young-Ku; Emery, Sherry

2013-08-01

Several statistical packages are capable of estimating generalized linear mixed models and these packages provide one or more of three estimation methods: penalized quasi-likelihood, Laplace, and Gauss-Hermite. Many studies have investigated these methods' performance for the mixed-effects logistic regression model. However, the authors focused on models with one or two random effects and assumed a simple covariance structure between them, which may not be realistic. When there are multiple correlated random effects in a model, the computation becomes intensive, and often an algorithm fails to converge. Moreover, in our analysis of smoking status and exposure to anti-tobacco advertisements, we have observed that when a model included multiple random effects, parameter estimates varied considerably from one statistical package to another even when using the same estimation method. This article presents a comprehensive review of the advantages and disadvantages of each estimation method. In addition, we compare the performances of the three methods across statistical packages via simulation, which involves two- and three-level logistic regression models with at least three correlated random effects. We apply our findings to a real dataset. Our results suggest that two packages-SAS GLIMMIX Laplace and SuperMix Gaussian quadrature-perform well in terms of accuracy, precision, convergence rates, and computing speed. We also discuss the strengths and weaknesses of the two packages in regard to sample sizes.

Logistic Regression with Multiple Random Effects: A Simulation Study of Estimation Methods and Statistical Packages

PubMed Central

Kim, Yoonsang; Emery, Sherry

2013-01-01

Several statistical packages are capable of estimating generalized linear mixed models and these packages provide one or more of three estimation methods: penalized quasi-likelihood, Laplace, and Gauss-Hermite. Many studies have investigated these methods’ performance for the mixed-effects logistic regression model. However, the authors focused on models with one or two random effects and assumed a simple covariance structure between them, which may not be realistic. When there are multiple correlated random effects in a model, the computation becomes intensive, and often an algorithm fails to converge. Moreover, in our analysis of smoking status and exposure to anti-tobacco advertisements, we have observed that when a model included multiple random effects, parameter estimates varied considerably from one statistical package to another even when using the same estimation method. This article presents a comprehensive review of the advantages and disadvantages of each estimation method. In addition, we compare the performances of the three methods across statistical packages via simulation, which involves two- and three-level logistic regression models with at least three correlated random effects. We apply our findings to a real dataset. Our results suggest that two packages—SAS GLIMMIX Laplace and SuperMix Gaussian quadrature—perform well in terms of accuracy, precision, convergence rates, and computing speed. We also discuss the strengths and weaknesses of the two packages in regard to sample sizes. PMID:24288415

Driving and off-road impairments underlying failure on road testing in Parkinson's disease.

PubMed

Devos, Hannes; Vandenberghe, Wim; Tant, Mark; Akinwuntan, Abiodun E; De Weerdt, Willy; Nieuwboer, Alice; Uc, Ergun Y

2013-12-01

Parkinson's disease (PD) affects driving ability. We aimed to determine the most critical impairments in specific road skills and in clinical characteristics leading to failure on a road test in PD. In this cross-sectional study, certified driving assessment experts evaluated specific driving skills in 104 active, licensed drivers with PD using a standardized, on-road checklist and issued a global decision of pass/fail. Participants also completed an off-road evaluation assessing demographic features, disease characteristics, motor function, vision, and cognition. The most important driving skills and off-road predictors of the pass/fail outcome were identified using multivariate stepwise regression analyses. Eighty-six (65%) passed and 36 (35%) failed the on-road driving evaluation. Persons who failed performed worse on all on-road items. When adjusted for age and gender, poor performances on lateral positioning at low speed, speed adaptations at high speed, and left turning maneuvers yielded the best model that determined the pass/fail decision (R(2) = 0.56). The fail group performed poorer on all motor, visual, and cognitive tests. Measures of visual scanning, motor severity, PD subtype, visual acuity, executive functions, and divided attention were independent predictors of pass/fail decisions in the multivariate model (R(2) = 0.60). Our study demonstrated that failure on a road test in PD is determined by impairments in specific driving skills and associated with deficits in motor, visual, executive, and visuospatial functions. These findings point to specific driving and off-road impairments that can be targeted in multimodal rehabilitation programs for drivers with PD. © 2013 Movement Disorder Society.

A Comprehensive Reliability Methodology for Assessing Risk of Reusing Failed Hardware Without Corrective Actions with and Without Redundancy

NASA Technical Reports Server (NTRS)

Putcha, Chandra S.; Mikula, D. F. Kip; Dueease, Robert A.; Dang, Lan; Peercy, Robert L.

1997-01-01

This paper deals with the development of a reliability methodology to assess the consequences of using hardware, without failure analysis or corrective action, that has previously demonstrated that it did not perform per specification. The subject of this paper arose from the need to provide a detailed probabilistic analysis to calculate the change in probability of failures with respect to the base or non-failed hardware. The methodology used for the analysis is primarily based on principles of Monte Carlo simulation. The random variables in the analysis are: Maximum Time of Operation (MTO) and operation Time of each Unit (OTU) The failure of a unit is considered to happen if (OTU) is less than MTO for the Normal Operational Period (NOP) in which this unit is used. NOP as a whole uses a total of 4 units. Two cases are considered. in the first specialized scenario, the failure of any operation or system failure is considered to happen if any of the units used during the NOP fail. in the second specialized scenario, the failure of any operation or system failure is considered to happen only if any two of the units used during the MOP fail together. The probability of failure of the units and the system as a whole is determined for 3 kinds of systems - Perfect System, Imperfect System 1 and Imperfect System 2. in a Perfect System, the operation time of the failed unit is the same as that of the MTO. In an Imperfect System 1, the operation time of the failed unit is assumed as 1 percent of the MTO. In an Imperfect System 2, the operation time of the failed unit is assumed as zero. in addition, simulated operation time of failed units is assumed as 10 percent of the corresponding units before zero value. Monte Carlo simulation analysis is used for this study. Necessary software has been developed as part of this study to perform the reliability calculations. The results of the analysis showed that the predicted change in failure probability (P(sub F)) for the previously failed units is as high as 49 percent above the baseline (perfect system) for the worst case. The predicted change in system P(sub F) for the previously failed units is as high as 36% for single unit failure without any redundancy. For redundant systems, with dual unit failure, the predicted change in P(sub F) for the previously failed units is as high as 16%. These results will help management to make decisions regarding the consequences of using previously failed units without adequate failure analysis or corrective action.

Screening for trisomies by cell-free DNA testing of maternal blood: consequences of a failed result.

PubMed

Revello, R; Sarno, L; Ispas, A; Akolekar, R; Nicolaides, K H

2016-06-01

First, to report the distribution of the fetal fraction of cell-free (cf) DNA and the rate of a failed cfDNA test result in trisomies 21, 18 and 13, by comparison with pregnancies unaffected by these trisomies, second, to examine the possible effects of maternal and fetal characteristics on the fetal fraction, and third, to consider the options for further management of pregnancies with a failed result. This was a cohort study of 10 698 singleton pregnancies undergoing screening for fetal trisomies 21, 18 and 13 by cfDNA testing at 10-14 weeks' gestation. There were 160 cases of trisomy 21, 50 of trisomy 18, 16 of trisomy 13 and 10 472 were unaffected by these trisomies. Multivariate regression analysis was used to determine significant predictors of fetal fraction and a failed cfDNA test result amongst maternal and fetal characteristics. Fetal fraction decreased with increasing body mass index and maternal age, was lower in women of South Asian racial origin than in Caucasians and in assisted compared to natural conceptions. It increased with fetal crown-rump length and higher levels of serum pregnancy-associated plasma protein-A and free β-human chorionic gonadotropin. The median fetal fraction was 11.0% (interquartile range (IQR), 8.3-14.4%) in the unaffected group, 10.7% (IQR, 7.8-14.3%) in trisomy 21, 8.6% (IQR, 5.0-10.2%) in trisomy 18 and 7.0% (IQR, 6.0-9.4%) in trisomy 13. There was a failed result from cfDNA testing after first sampling in 2.9% of the unaffected group, 1.9% of trisomy 21, 8.0% of trisomy 18 and 6.3% of trisomy 13. In the cases with a failed result, 7% of women had invasive testing, mainly because of high risk from the combined test and/or presence of sonographic features suggestive of trisomies 18 and 13. All cases of trisomies were detected prenatally. In cases of a failed cfDNA test, the rate of trisomies 18 and 13, but not trisomy 21, is higher than in those with a successful test. In the management of such cases, the decision in favor of invasive testing should depend on the risk of prior screening and the results of detailed ultrasound examination. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Estimating Full IM240 Emissions from Partial Test Results: Evidence from Arizona.

PubMed

Ando, Amy W; Harrington, Winston; McConnell, Virginia

1999-10-01

The expense and inconvenience of enhanced-vehicle-emissions testing using the full 240-second dynamometer test has led states to search for ways to shorten the test process. In fact, all states that currently use the IM240 allow some type of fast-pass, usually as early in the test as second 31, and Arizona has allowed vehicles to fast-fail after second 93. While these shorter tests save states millions of dollars in inspection lanes and driver costs, there is a loss of information since test results are no longer comparable across vehicles. This paper presents a methodology for estimating full 240-second results from partial-test results for three pollutants: HC, CO, and NO x . If states can convert all tests to consistent IM240 readings, they will be able to better characterize fleet emissions and to evaluate the impact of inspection and maintenance and other programs on emissions over time. Using a random sample of vehicles in Arizona which received full 240-second tests, we use regression analysis to estimate the relationship between emissions at second 240 and emissions at earlier seconds in the test. We examine the influence of other variables such as age, model-year group, and the pollution level itself on this relationship. We also use the estimated coefficients in several applications. First, we try to shed light on the frequent assertion that the results of the dynamometer test provide guidance for vehicle repair of failing vehicles. Using a probit analysis, we find that the probability that a failing vehicle will pass the test on the first retest is greater the longer the test has progressed. Second, we test the accuracy of our estimates for forecasting fleet emissions from partial-test emissions results in Arizona. We find forecasted fleet average emissions to be very close to the actual fleet averages for light-duty vehicles, but not quite as good for trucks, particularly when NO x emissions are forecast.

Standard Setting Methods for Pass/Fail Decisions on High-Stakes Objective Structured Clinical Examinations: A Validity Study.

PubMed

Yousuf, Naveed; Violato, Claudio; Zuberi, Rukhsana W

2015-01-01

CONSTRUCT: Authentic standard setting methods will demonstrate high convergent validity evidence of their outcomes, that is, cutoff scores and pass/fail decisions, with most other methods when compared with each other. The objective structured clinical examination (OSCE) was established for valid, reliable, and objective assessment of clinical skills in health professions education. Various standard setting methods have been proposed to identify objective, reliable, and valid cutoff scores on OSCEs. These methods may identify different cutoff scores for the same examinations. Identification of valid and reliable cutoff scores for OSCEs remains an important issue and a challenge. Thirty OSCE stations administered at least twice in the years 2010-2012 to 393 medical students in Years 2 and 3 at Aga Khan University are included. Psychometric properties of the scores are determined. Cutoff scores and pass/fail decisions of Wijnen, Cohen, Mean-1.5SD, Mean-1SD, Angoff, borderline group and borderline regression (BL-R) methods are compared with each other and with three variants of cluster analysis using repeated measures analysis of variance and Cohen's kappa. The mean psychometric indices on the 30 OSCE stations are reliability coefficient = 0.76 (SD = 0.12); standard error of measurement = 5.66 (SD = 1.38); coefficient of determination = 0.47 (SD = 0.19), and intergrade discrimination = 7.19 (SD = 1.89). BL-R and Wijnen methods show the highest convergent validity evidence among other methods on the defined criteria. Angoff and Mean-1.5SD demonstrated least convergent validity evidence. The three cluster variants showed substantial convergent validity with borderline methods. Although there was a high level of convergent validity of Wijnen method, it lacks the theoretical strength to be used for competency-based assessments. The BL-R method is found to show the highest convergent validity evidences for OSCEs with other standard setting methods used in the present study. We also found that cluster analysis using mean method can be used for quality assurance of borderline methods. These findings should be further confirmed by studies in other settings.

[Possibility and predictors of successful cigarette purchase attempts by 201 primary school students in Guangzhou, China].

PubMed

Wen, Xiao-zhong; Huang, Jian-hua; Chen, Wei-qing; Liang, Cai-hua; Han, Ke; Ling, Wen-hua

2007-01-01

To explore the access to tobacco and exam the predictors of successful tobacco purchase attempts among Chinese minors. A simulative trial of purchasing cigarettes was participated by 201 sixth grade students to assess the prevalence of illegal cigarette sales to minors in Guangzhou. Methods of Chi-square and unconditional logistic regression were used to identify the significant predictors,with the result of tobacco purchase as the dependent variable and the characteristics of stores, retailers and minors as the independent variables. A total of 165 students succeeded in purchasing cigarettes but 36 failed, and the percentage of successful purchase attempts was 82. 1% . Data from univariate analysis indicated that 9 factors were significantly associated with students' success in purchasing cigarettes. They were age and height of the purchasers, types of stores, seller's gender and age, posting cigarette advertisements,showing warning signs of 'no cigarette selling to minors' ,asking buyer's age,and asking whom you buy the cigarettes for. The results of multivariable analysis showed that only three variables entering the final logistic regression: the age of students, the type of stores, and showing warning signs of 'no cigarette selling to minors'. Chinese minors have easy access to purchasing cigarettes, especially in groceries and small markets. Selling cigarettes by sellers to minors should be monitored and managed in the future.

The effect of playing tactics and situational variables on achieving score-box possessions in a professional soccer team.

PubMed

Lago-Ballesteros, Joaquin; Lago-Peñas, Carlos; Rey, Ezequiel

2012-01-01

The aim of this study was to analyse the influence of playing tactics, opponent interaction and situational variables on achieving score-box possessions in professional soccer. The sample was constituted by 908 possessions obtained by a team from the Spanish soccer league in 12 matches played during the 2009-2010 season. Multidimensional qualitative data obtained from 12 ordered categorical variables were used. Sampled matches were registered by the AMISCO PRO system. Data were analysed using chi-square analysis and multiple logistic regression analysis. Of 908 possessions, 303 (33.4%) produced score-box possessions, 477 (52.5%) achieved progression and 128 (14.1%) failed to reach any sort of progression. Multiple logistic regression showed that, for the main variable "team possession type", direct attacks and counterattacks were three times more effective than elaborate attacks for producing a score-box possession (P < 0.05). Team possession originating from the middle zones and playing against less than six defending players (P < 0.001) registered a higher success than those started in the defensive zone with a balanced defence. When the team was drawing or winning, the probability of reaching the score-box decreased by 43 and 53 percent, respectively, compared with the losing situation (P < 0.05). Accounting for opponent interactions and situational variables is critical to evaluate the effectiveness of offensive playing tactics on producing score-box possessions.

Predictors of free flap loss in the head and neck region: A four-year retrospective study with 451 microvascular transplants at a single centre.

PubMed

Mücke, Thomas; Ritschl, Lucas M; Roth, Maximilian; Güll, Florian D; Rau, Andrea; Grill, Sonja; Kesting, Marco R; Wolff, Klaus-Dietrich; Loeffelbein, Denys J

2016-09-01

Microvascular free flaps have become an essential part of reconstructive surgery following head and neck tumour ablation. The authors' aim was to investigate the influence of cardiovascular risk factors, preoperative irradiation, previous operations and metabolically active medication on free flap loss in order to predict patients at risk and to improve their therapy. All patients who underwent reconstructive surgery with microvascular free flaps in the head and neck region between 2009 and 2013 were retrospectively analysed. Uni- and multivariate logistic regressions were performed to determine the association between possible predictor variables for free flap loss. We included 451 patients in our analysis. The overall free flap failure rate was 4.0%. Multivariate regression analysis revealed significantly increased risks of free flap failure depending on prior attempts at microvascular transplants (p < 0.001, OR = 14.21) and length of hospitalisation (p = 0.007, OR = 1.05). With consistently low rates of flap failure, microvascular reconstruction of defects in the head and neck region has proven to be highly reliable, even in patients with comorbidities. The expertise of the operating team seems to remain the main factor affecting flap success. The only discerned independent predictor was previously failed attempts at microvascular reconstruction. Copyright © 2016 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Risk factors associated with intestinal necrosis in children with failed non-surgical reduction for intussusception.

PubMed

Huang, Hui-Ya; Huang, Xiao-Zhong; Han, Yi-Jiang; Zhu, Li-Bin; Huang, Kai-Yu; Lin, Jing; Li, Zhong-Rong

2017-05-01

Intestinal necrosis is the most serious complication of intussusception. The risk factors associated with intestinal necrosis in pediatric patients with intussusception have not been well characterized. This study aimed to investigate the risk factors associated with intestinal necrosis in pediatric patients with failed non-surgical reduction for intussusception. Hospitalized patients who failed the air-enema reduction for intussusception in the outpatient department and subsequently underwent surgery were retrospectively reviewed. All cases were categorized into two groups: intestinal necrosis group and non-intestinal necrosis group based on the surgical findings. Demographic and clinical features including the findings from the surgery were recorded and analyzed. Factors associated with intestinal necrosis were analyzed using univariate and multivariate unconditional logistic regression analyses. A total of 728 cases were included. Among them, 171 had intestinal necrosis at the time of surgery. The group with intestinal necrosis had a longer duration of symptom or length of illness (P = 0.000), and younger (P = 0.000) than the non-intestinal necrosis group. Complex/compound type of intussusceptions is more likely to have intestinal necrosis. Multivariate analysis showed that the presence of grossly bloody stool (OR = 2.12; 95% CI 1.19-3.76, P = 0.010) and duration of symptom (OR = 1.07; 95% CI 1.06-1.08, P = 0.000) were independent risk factors for intestinal necrosis in patients hospitalized for surgical reduction for intussusceptions. At time of admission, the presence of bloody stools and duration of symptom are the important risk factors for developing intestinal necrosis for those patients who failed non-surgical reduction. The length of illness has the highest sensitivity and specificity to correlate with intestinal necrosis. This finding may suggest that we should take the intussusception cases that have the longer duration of symptom directly to operation room for reduction.

Outcome of Descemet stripping automated endothelial keratoplasty in eyes with an Ahmed glaucoma valve.

PubMed

Chiam, Patrick J; Cheeseman, Robert; Ho, Vivian W; Romano, Vito; Choudhary, Anshoo; Batterbury, Mark; Kaye, Stephen B; Willoughby, Colin E

2017-05-01

The purpose was to investigate the survival of Descemet stripping automated endothelial keratoplasty (DSAEK) in eyes with an Ahmed glaucoma valve (AGV). The study had a retrospective case-series of patients with an AGV in the anterior chamber undergoing a DSAEK. Included in the analysis were graft size, number of previous operations, post-operative glaucoma medications, post-operative intraocular pressure (IOP) control, graft size and donor factors (age, endothelial cell density, and post-mortem time). A generalised linear model with binary logistic regression was used to test for an effect on graft survival at 1 year and 1.5 years. Fourteen eyes from 13 patients were included. The survival rate of the first DSAEK at 6, 12, 18, 24 and 30-months was 85%, 71%, 50%, 36% and 30%, respectively. The mean duration to graft failure was 12.9 ± 6.2 months. Five of the seven failed first grafts went on to have a repeat DSAEK. The mean follow-up in this subgroup was 30.7 ± 18.4 months. The survival rate of second DSAEK at 6, 12, 18 and 24 months was 100% (5/5), 100% (5/5), 75% (3/4) and 67% (2/3). Only one second DSAEK failed in the duration of the study and went on to receive a third DSAEK which failed at 18-months. The mean IOP within the first year was significantly lower for grafts that survived at 1 and 1.5 years (17.4 mmHg, 16.9 mmHg) than for grafts that failed (19.4 mmHg, 19.4 mmHg) (p = 0.04, p = 0.009). DSAEK is a viable alternative to PK to restore visual function in eyes with an AGV sited in the anterior chamber. IOP is an important risk factor for graft failure.

Outcome of selective non-operative management of penetrating abdominal injuries from the North American National Trauma Database.

PubMed

Zafar, S N; Nabeel Zafar, S; Rushing, A; Haut, E R; Kisat, M T; Villegas, C V; Chi, A; Stevens, K; Efron, D T; Zafar, H; Haider, A H

2012-01-01

The aim of this study was to investigate trends in the practice of selective non-operative management (SNOM) for penetrating abdominal injury (PAI) and to determine factors associated with its failure. The National Trauma Data Bank for 2002-2008 was reviewed. Patients with PAI were categorized as those who underwent successful SNOM (operative management not required) and those who failed SNOM (surgery required more than 4 h after admission). Yearly rates of SNOM versus non-therapeutic laparotomy (NTL) were plotted. Multivariable regression analysis was performed to identify factors associated with failed SNOM and mortality. A total of 12 707 patients with abdominal gunshot and 13 030 with stab wounds were identified. Rates of SNOM were 22.2 per cent for gunshot and 33.9 per cent for stab wounds, and increased with time (P < 0.001). There was a strong correlation between the rise in SNOM and the decline in NTL (r = - 0.70). SNOM failed in 20.8 and 15.2 per cent of patients with gunshot and stab wounds respectively. Factors predicting failure included the need for blood transfusion (odds ratio (OR) 1.96, 95 per cent confidence interval 1.11 to 3.46) and a higher injury score. Failed SNOM was independently associated with mortality in both the gunshot (OR 4.48, 2.07 to 9.70) and stab (OR 9.83, 3.44 to 28.00) wound groups. The practice of SNOM is increasing, with an associated decrease in the rate of NTL for PAI. In most instances SNOM is successful; however, its failure is associated with increased mortality. Careful patient selection and adherence to protocols designed to decrease the failure rate of SNOM are recommended. Copyright © 2011 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd.

High soluble CD30 levels and associated anti-HLA antibodies in patients with failed renal allografts.

PubMed

Karahan, Gonca E; Caliskan, Yasar; Ozdilli, Kursat; Kekik, Cigdem; Bakkaloglu, Huseyin; Caliskan, Bahar; Turkmen, Aydin; Sever, Mehmet S; Oguz, Fatma S

2017-01-13

Serum soluble CD30 (sCD30), a 120-kD glycoprotein that belongs to the tumor necrosis factor receptor family, has been suggested as a marker of rejection in kidney transplant patients. The aim of this study was to evaluate the relationship between sCD30 levels and anti-HLA antibodies, and to compare sCD30 levels in patients undergoing hemodialysis (HD) with and without failed renal allografts and transplant recipients with functioning grafts. 100 patients undergoing HD with failed grafts (group 1), 100 patients undergoing HD who had never undergone transplantation (group 2), and 100 kidney transplant recipients (group 3) were included in this study. Associations of serum sCD30 levels and anti-HLA antibody status were analyzed in these groups. The sCD30 levels of group 1 and group 2 (154 ± 71 U/mL and 103 ± 55 U/mL, respectively) were significantly higher than those of the transplant recipients (group 3) (39 ± 21 U/mL) (p<0.001 and p<0.001). The serum sCD30 levels in group 1 (154 ± 71 U/mL) were also significantly higher than group 2 (103 ± 55 U/mL) (p<0.001). Anti-HLA antibodies were detected in 81 (81%) and 5 (5%) of patients in groups 1 and 2, respectively (p<0.001). When multiple regression analysis was performed to predict sCD30 levels, the independent variables in group 1 were the presence of class I anti-HLA antibodies (β = 0.295; p = 0.003) and age (β = -0.272; p = 0.005), and serum creatinine (β = 0.218; p = 0.027) and presence of class II anti-HLA antibodies (standardized β = 0.194; p = 0.046) in group 3. Higher sCD30 levels and anti-HLA antibodies in patients undergoing HD with failed renal allografts may be related to higher inflammatory status in these patients.

Nonparametric Bayesian Multiple Imputation for Incomplete Categorical Variables in Large-Scale Assessment Surveys

ERIC Educational Resources Information Center

Si, Yajuan; Reiter, Jerome P.

2013-01-01

In many surveys, the data comprise a large number of categorical variables that suffer from item nonresponse. Standard methods for multiple imputation, like log-linear models or sequential regression imputation, can fail to capture complex dependencies and can be difficult to implement effectively in high dimensions. We present a fully Bayesian,…

Mammary Hypertrophy in an Ovariohysterectomized Cat

PubMed Central

Pukay, B.P.; Stevenson, D.A.

1983-01-01

A four year old ovariohysterectomized domestic short-haired cat under treatment for behavioral urine spraying and idiopathic alopecia developed mammary gland hypertrophy following treatment with megestrol acetate. Withdrawal of the progestin and treatment with androgen failed to cause regression of the hypertrophy. The affected mammary gland was surgically excised and recovery was uneventful. ImagesFigure 1. PMID:17422254

Adolescent Work and Alcohol Use Revisited: Variations by Family Structure

ERIC Educational Resources Information Center

Rocheleau, Gregory C.; Swisher, Raymond R.

2012-01-01

Previous research finds adolescent work hours to be associated with increased alcohol use. Most studies, however, fail to account for possible selection effects that lead youth to both work and substance use. Using data from the first two waves of the National Longitudinal Study of Adolescent Health (N = 12,620), a fixed effects regression method…

SU-C-304-05: Use of Local Noise Power Spectrum and Wavelets in Comprehensive EPID Quality Assurance

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

Lee, S; Gopal, A; Yan, G

2015-06-15

Purpose: As EPIDs are increasingly used for IMRT QA and real-time treatment verification, comprehensive quality assurance (QA) of EPIDs becomes critical. Current QA with phantoms such as the Las Vegas and PIPSpro™ can fail in the early detection of EPID artifacts. Beyond image quality assessment, we propose a quantitative methodology using local noise power spectrum (NPS) to characterize image noise and wavelet transform to identify bad pixels and inter-subpanel flat-fielding artifacts. Methods: A total of 93 image sets including bar-pattern images and open exposure images were collected from four iViewGT a-Si EPID systems over three years. Quantitative metrics such asmore » modulation transform function (MTF), NPS and detective quantum efficiency (DQE) were computed for each image set. Local 2D NPS was calculated for each subpanel. A 1D NPS was obtained by radial averaging the 2D NPS and fitted to a power-law function. R-square and slope of the linear regression analysis were used for panel performance assessment. Haar wavelet transformation was employed to identify pixel defects and non-uniform gain correction across subpanels. Results: Overall image quality was assessed with DQE based on empirically derived area under curve (AUC) thresholds. Using linear regression analysis of 1D NPS, panels with acceptable flat fielding were indicated by r-square between 0.8 and 1, and slopes of −0.4 to −0.7. However, for panels requiring flat fielding recalibration, r-square values less than 0.8 and slopes from +0.2 to −0.4 were observed. The wavelet transform successfully identified pixel defects and inter-subpanel flat fielding artifacts. Standard QA with the Las Vegas and PIPSpro phantoms failed to detect these artifacts. Conclusion: The proposed QA methodology is promising for the early detection of imaging and dosimetric artifacts of EPIDs. Local NPS can accurately characterize the noise level within each subpanel, while the wavelet transforms can detect bad pixels and inter-subpanel flat fielding artifacts.« less

Gender-Related and Age-Related Differences in Implantable Defibrillator Recipients: Results From the Pacemaker and Implantable Defibrillator Leads Survival Study ("PAIDLESS").

PubMed

Feldman, Alyssa M; Kersten, Daniel J; Chung, Jessica A; Asheld, Wilbur J; Germano, Joseph; Islam, Shahidul; Cohen, Todd J

2015-12-01

The purpose of this study was to investigate the influences of gender and age on defibrillator lead failure and patient mortality. The specific influences of gender and age on defibrillator lead failure have not previously been investigated. This study analyzed the differences in gender and age in relation to defibrillator lead failure and mortality of patients in the Pacemaker and Implantable Defibrillator Leads Survival Study ("PAIDLESS"). PAIDLESS includes all patients at Winthrop University Hospital who underwent defibrillator lead implantation between February 1, 1996 and December 31, 2011. Male and female patients were compared within each age decile, beginning at 15 years old, to analyze lead failure and patient mortality. Statistical analyses were performed using Wilcoxon rank-sum test, Fisher's exact test, Kaplan-Meier analysis, and multivariable Cox regression models. P<.05 was considered statistically significant. No correction for multiple comparisons was performed for the subgroup analyses. A total of 3802 patients (2812 men and 990 women) were included in the analysis. The mean age was 70 ± 13 years (range, 15-94 years). Kaplan-Meier analysis found that between 45 and 54 years of age, leads implanted in women failed significantly faster than in men (P=.03). Multivariable Cox regression models were built to validate this finding, and they confirmed that male gender was an independent protective factor of lead failure in the 45 to 54 years group (for male gender: HR, 0.37; 95% confidence interval, 0.14-0.96; P=.04). Lead survival time for women in this age group was 13.4 years (standard error, 0.6), while leads implanted in men of this age group survived 14.7 years (standard error, 0.3). Although there were significant differences in lead failure, no differences in mortality between the genders were found for any ages or within each decile. This study is the first to compare defibrillator lead failure and patient mortality in relation to gender and age deciles at a single large implanting center. Within the 45 to 54 years group, leads implanted in women failed faster than in men. Male gender was found to be an independent protective factor in lead survival. This study emphasizes the complex interplay between gender and age with respect to implantable defibrillator lead failure and mortality.

Current clinical nutrition practices in critically ill patients in Latin America: a multinational observational study.

PubMed

Vallejo, Karin Papapietro; Martínez, Carolina Méndez; Matos Adames, Alfredo A; Fuchs-Tarlovsky, Vanessa; Nogales, Guillermo Carlos Contreras; Paz, Roger Enrique Riofrio; Perman, Mario Ignacio; Correia, Maria Isabel Toulson Davisson; Waitzberg, Dan Linetzky

2017-08-25

Malnutrition in critically ill adults in the intensive care unit (ICU) is associated with a significantly elevated risk of mortality. Adequate nutrition therapy is crucial to optimise outcomes. Currently, there is a paucity of such data in Latin America. Our aims were to characterise current clinical nutrition practices in the ICU setting in Latin America and evaluate whether current practices meet caloric and protein requirements in critically ill patients receiving nutrition therapy. We conducted a cross-sectional, retrospective, observational study in eight Latin American countries (Argentina, Brazil, Chile, Colombia, Ecuador, Mexico, Panama, and Peru). Eligible patients were critically ill adults hospitalised in the ICU and receiving enteral nutrition (EN) and/or parenteral nutrition (PN) on the Screening Day and the previous day (day -1). Caloric and protein balance on day -1, nutritional status, and prescribed nutrition therapy were recorded. Multivariable logistic regression analysis was performed to identify independent predictors of reaching daily caloric and protein targets. The analysis included 1053 patients from 116 hospitals. Evaluation of nutritional status showed that 74.1% of patients had suspected/moderate or severe malnutrition according to the Subjective Global Assessment. Prescribed nutrition therapy included EN alone (79.9%), PN alone (9.4%), and EN + PN (10.7%). Caloric intake met >90% of the daily target in 59.7% of patients on day -1; a caloric deficit was present in 40.3%, with a mean (±SD) daily caloric deficit of -688.8 ± 455.2 kcal. Multivariable logistic regression analysis showed that combined administration of EN + PN was associated with a statistically significant increase in the probability of meeting >90% of daily caloric and protein targets compared with EN alone (odds ratio, 1.56; 95% confidence interval, 1.02-2.39; p = 0.038). In the ICU setting in Latin America, malnutrition was highly prevalent and caloric intake failed to meet targeted energy delivery in 40% of critically ill adults receiving nutrition therapy. Supplemental administration of PN was associated with improved energy and protein delivery; however, PN use was low. Collectively, these findings suggest an opportunity for more effective utilisation of supplemental PN in critically ill adults who fail to receive adequate nutrition from EN alone.

Factors associated with quitting areca (betel) quid chewing.

PubMed

Lai, Ching-Shiun; Shieh, Tien-Yu; Yang, Yi-Hsin Connie; Chong, Mian-Yoon; Hung, Hsin-Chia; Tsai, Chi-Cheng

2006-12-01

The purpose of this study was to provide useful data for a future abstinence project by identifying the factors related to quitting areca (betel) quid chewing. The study was cross-sectional. Data on demographic variables, psychological factors and substance-use behaviors were collected via questionnaires from 326 participants. Multiple logistic regression analysis indicated that the areca/betel quid chewers who were less educated (OR = 0.58, 95% CI = 0.34-0.98) were least likely to try to give up. Among the chewers who tried to quit, those employed as full-time drivers (OR = 2.24, 95% CI = 1.14-4.39), who had drinking habits (OR = 2.41, 95% CI = 1.24-4.66), and who preferred to chew only betel quid wrapped with leaf (OR = 4.44, 95% CI = 1.99-9.90) were more likely to fail. Chewers who successfully quit had a higher internal health locus of control compared with those who failed to quit (one-point increments, OR = 0.94, 95% CI = 0.90-0.98). The results suggest that health educators and researchers can better influence people's chewing behavior if the importance of chewers' education level, job type, substance use (i.e. drinking habits, type of betel quid), and level of health locus of control are all taken into consideration when devising interventions.

The Importance of Gestational Sac Size of Ectopic Pregnancy in Response to Single-Dose Methotrexate

PubMed Central

Kimiaei, Parichehr; Khani, Zahra; Marefian, Azadeh; Gholampour Ghavamabadi, Maryam; Salimnejad, Maryam

2013-01-01

This retrospective cohort study was designed in a selective group of 185 patients diagnosed with and treated for ectopic pregnancy. Intramuscular administration of a single dose of methotrexate (50 mg/m2) was performed to measure predictors of failure or resistance to treatment necessitating surgical intervention. During the time of treatment with a single dose of MTX, 20 patients (10.8%) failed to response, in which 6 of 20 (30%) indicated side effects to MTX and rupture of the ectopic pregnancy. Remaining cases (n = 14) showed resistance to the drug; the level of β-hCG did not fall at least 15% during 7 days after treatment and necessitated laparotomy. In backward-step analysis by multiple logistic regressions of various types of predictor factors, size of gestational sac (coefficient = 1.91, OR = 6.78, 95% confidence interval = 3.18–8.22) and baseline level β-hCG (coefficient = 1.60, OR = 5.0, 95% confidence interval = 4.26–6.72) had significant correlation with leading EP patients failing to response to MTX. This study suggests that further investigation for finding relative contraindications of MTX treatment in EP women should be considered on the gestational sac size because other variables are in the causal pathway of this variable. PMID:23762575

Analysis of Wind Tunnel Lateral Oscillatory Data of the F-16XL Aircraft

NASA Technical Reports Server (NTRS)

Klein, Vladislav; Murphy, Patrick C.; Szyba, Nathan M.

2004-01-01

Static and dynamic wind tunnel tests were performed on an 18% scale model of the F-16XL aircraft. These tests were performed over a wide range of angles of attack and sideslip with oscillation amplitudes from 5 deg. to 30 deg. and reduced frequencies from 0.073 to 0.269. Harmonic analysis was used to estimate Fourier coefficients and in-phase and out-of-phase components. For frequency dependent data from rolling oscillations, a two-step regression method was used to obtain unsteady models (indicial functions), and derivatives due to sideslip angle, roll rate and yaw rate from in-phase and out-of-phase components. Frequency dependence was found for angles of attack between 20 deg. and 50 deg. Reduced values of coefficient of determination and increased values of fit error were found for angles of attack between 35 deg. and 45 deg. An attempt to estimate model parameters from yaw oscillations failed, probably due to the low number of test cases at different frequencies.

Normalization of RNA-seq data using factor analysis of control genes or samples

PubMed Central

Risso, Davide; Ngai, John; Speed, Terence P.; Dudoit, Sandrine

2015-01-01

Normalization of RNA-seq data has proven essential to ensure accurate inference of expression levels. Here we show that usual normalization approaches mostly account for sequencing depth and fail to correct for library preparation and other more-complex unwanted effects. We evaluate the performance of the External RNA Control Consortium (ERCC) spike-in controls and investigate the possibility of using them directly for normalization. We show that the spike-ins are not reliable enough to be used in standard global-scaling or regression-based normalization procedures. We propose a normalization strategy, remove unwanted variation (RUV), that adjusts for nuisance technical effects by performing factor analysis on suitable sets of control genes (e.g., ERCC spike-ins) or samples (e.g., replicate libraries). Our approach leads to more-accurate estimates of expression fold-changes and tests of differential expression compared to state-of-the-art normalization methods. In particular, RUV promises to be valuable for large collaborative projects involving multiple labs, technicians, and/or platforms. PMID:25150836

Consumer-choice health plan (first of two parts). Inflation and inequity in health care today: alternatives for cost control and an analysis of proposals for national health insurance.

PubMed

Enthoven, A C

1978-03-23

The financing system for medical costs in this country suffers from severe inflation and inequity. The tax-supported system of fee for service for doctors, third-party intermediaries and cost reimbursement for hospitals produces inflation by rewarding cost-increasing behavior and failing to provide incentives for economy. The system is inequitable because the government pays more on behalf of those who choose more costly systems of care, because tax benefits subsidize the health insurance of the well-to-do, while not helping many low-income people, and because employment health insurance does not guarantee continuity of coverage and is regressive in its financing. Analysis of previous proposals for national health insurance shows none to be capable of solving most of these problems. Direct economic regulation by government will not improve the situation. Cost controls through incentives and regulated competition in the private sector are most likely to be effective.

Parameterization of phosphine ligands demonstrates enhancement of nickel catalysis via remote steric effects.

PubMed

Wu, Kevin; Doyle, Abigail G

2017-08-01

The field of Ni-catalysed cross-coupling has seen rapid recent growth because of the low cost of Ni, its earth abundance, and its ability to promote unique cross-coupling reactions. Whereas advances in the related field of Pd-catalysed cross-coupling have been driven by ligand design, the development of ligands specifically for Ni has received minimal attention. Here, we disclose a class of phosphines that enable the Ni-catalysed Csp 3 Suzuki coupling of acetals with boronic acids to generate benzylic ethers, a reaction that failed with known ligands for Ni and designer phosphines for Pd. Using parameters to quantify phosphine steric and electronic properties together with regression statistical analysis, we identify a model for ligand success. The study suggests that effective phosphines feature remote steric hindrance, a concept that could guide future ligand design tailored to Ni. Our analysis also reveals that two classic descriptors for ligand steric environment-cone angle and % buried volume-are not equivalent, despite their treatment in the literature.

Parameterization of phosphine ligands demonstrates enhancement of nickel catalysis via remote steric effects

NASA Astrophysics Data System (ADS)

Wu, Kevin; Doyle, Abigail G.

2017-08-01

The field of Ni-catalysed cross-coupling has seen rapid recent growth because of the low cost of Ni, its earth abundance, and its ability to promote unique cross-coupling reactions. Whereas advances in the related field of Pd-catalysed cross-coupling have been driven by ligand design, the development of ligands specifically for Ni has received minimal attention. Here, we disclose a class of phosphines that enable the Ni-catalysed Csp3 Suzuki coupling of acetals with boronic acids to generate benzylic ethers, a reaction that failed with known ligands for Ni and designer phosphines for Pd. Using parameters to quantify phosphine steric and electronic properties together with regression statistical analysis, we identify a model for ligand success. The study suggests that effective phosphines feature remote steric hindrance, a concept that could guide future ligand design tailored to Ni. Our analysis also reveals that two classic descriptors for ligand steric environment—cone angle and % buried volume—are not equivalent, despite their treatment in the literature.

Q-learning residual analysis: application to the effectiveness of sequences of antipsychotic medications for patients with schizophrenia.

PubMed

Ertefaie, Ashkan; Shortreed, Susan; Chakraborty, Bibhas

2016-06-15

Q-learning is a regression-based approach that uses longitudinal data to construct dynamic treatment regimes, which are sequences of decision rules that use patient information to inform future treatment decisions. An optimal dynamic treatment regime is composed of a sequence of decision rules that indicate how to optimally individualize treatment using the patients' baseline and time-varying characteristics to optimize the final outcome. Constructing optimal dynamic regimes using Q-learning depends heavily on the assumption that regression models at each decision point are correctly specified; yet model checking in the context of Q-learning has been largely overlooked in the current literature. In this article, we show that residual plots obtained from standard Q-learning models may fail to adequately check the quality of the model fit. We present a modified Q-learning procedure that accommodates residual analyses using standard tools. We present simulation studies showing the advantage of the proposed modification over standard Q-learning. We illustrate this new Q-learning approach using data collected from a sequential multiple assignment randomized trial of patients with schizophrenia. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Clinical effectiveness and safety of leflunomide in inflammatory arthritis: a report from the RAPPORT database with supporting patient survey.

PubMed

Schultz, Morgan; Keeling, Stephanie O; Katz, Steven J; Maksymowych, Walter P; Eurich, Dean T; Hall, Jill J

2017-07-01

Leflunomide is indicated for the treatment of adults with rheumatoid arthritis, yet is underutilized. Given the cost of biologic therapy, understanding real-life effectiveness, safety, and sustainability of leflunomide, particularly in patients who have failed methotrexate, would be of value. The primary objective was to assess the proportion of patients achieving clinically meaningful benefit following an adequate trial of leflunomide. A retrospective analysis of a cohort supplemented with patient self-reported data using a standardized questionnaire. Data were analyzed using descriptive statistics, with a database multivariate logistic regression analysis to determine predictors of leflunomide response. Of the cohort available (N = 2591), 1671 patients with confirmed leflunomide use were included in the retrospective analysis, of whom 249 were incident users. Low disease activity (DAS-28 < 3.2) was achieved or maintained by 20% of incident users, with 19% achieving a clinical response (DAS-28 decrease ≥1.2) at 3 months. Adverse effects (AE) were reported by 29% of incident users and after 1 year, 45% remained on leflunomide. Achievement of "minimal or no joint symptoms" was reported by 34% in the 661 analyzable survey responses (39% response rate). AE were reported by 55%, with nuisance (hair loss, nausea, stomach pain) AE and diarrhea being most common. Leflunomide was discontinued by 67% of responders within 1 year. An important proportion of patients, the majority of whom had previously failed methotrexate, achieved disease response with leflunomide with a low risk of serious adverse effects, suggesting that a trial of leflunomide may be a reasonable and cost-effective strategy prior to biologic therapy.

Exploratory Network Meta Regression Analysis of Stroke Prevention in Atrial Fibrillation Fails to Identify Any Interactions with Treatment Effect.

PubMed

Batson, Sarah; Sutton, Alex; Abrams, Keith

2016-01-01

Patients with atrial fibrillation are at a greater risk of stroke and therefore the main goal for treatment of patients with atrial fibrillation is to prevent stroke from occurring. There are a number of different stroke prevention treatments available to include warfarin and novel oral anticoagulants. Previous network meta-analyses of novel oral anticoagulants for stroke prevention in atrial fibrillation acknowledge the limitation of heterogeneity across the included trials but have not explored the impact of potentially important treatment modifying covariates. To explore potentially important treatment modifying covariates using network meta-regression analyses for stroke prevention in atrial fibrillation. We performed a network meta-analysis for the outcome of ischaemic stroke and conducted an exploratory regression analysis considering potentially important treatment modifying covariates. These covariates included the proportion of patients with a previous stroke, proportion of males, mean age, the duration of study follow-up and the patients underlying risk of ischaemic stroke. None of the covariates explored impacted relative treatment effects relative to placebo. Notably, the exploration of 'study follow-up' as a covariate supported the assumption that difference in trial durations is unimportant in this indication despite the variation across trials in the network. This study is limited by the quantity of data available. Further investigation is warranted, and, as justifying further trials may be difficult, it would be desirable to obtain individual patient level data (IPD) to facilitate an effort to relate treatment effects to IPD covariates in order to investigate heterogeneity. Observational data could also be examined to establish if there are potential trends elsewhere. The approach and methods presented have potentially wide applications within any indication as to highlight the potential benefit of extending decision problems to include additional comparators outside of those of primary interest to allow for the exploration of heterogeneity.

Predictors of pain relief following spinal cord stimulation in chronic back and leg pain and failed back surgery syndrome: a systematic review and meta-regression analysis.

PubMed

Taylor, Rod S; Desai, Mehul J; Rigoard, Philippe; Taylor, Rebecca J

2014-07-01

We sought to assess the extent to which pain relief in chronic back and leg pain (CBLP) following spinal cord stimulation (SCS) is influenced by patient-related factors, including pain location, and technology factors. A number of electronic databases were searched with citation searching of included papers and recent systematic reviews. All study designs were included. The primary outcome was pain relief following SCS, we also sought pain score (pre- and post-SCS). Multiple predictive factors were examined: location of pain, history of back surgery, initial level of pain, litigation/worker's compensation, age, gender, duration of pain, duration of follow-up, publication year, continent of data collection, study design, quality score, method of SCS lead implant, and type of SCS lead. Between-study association in predictive factors and pain relief were assessed by meta-regression. Seventy-four studies (N = 3,025 patients with CBLP) met the inclusion criteria; 63 reported data to allow inclusion in a quantitative analysis. Evidence of substantial statistical heterogeneity (P < 0.0001) in level of pain relief following SCS was noted. The mean level of pain relief across studies was 58% (95% CI: 53% to 64%, random effects) at an average follow-up of 24 months. Multivariable meta-regression analysis showed no predictive patient or technology factors. SCS was effective in reducing pain irrespective of the location of CBLP. This review supports SCS as an effective pain relieving treatment for CBLP with predominant leg pain with or without a prior history of back surgery. Randomized controlled trials need to confirm the effectiveness and cost-effectiveness of SCS in the CLBP population with predominant low back pain. © 2013 The Authors Pain Practice Published by Wiley Periodicals, Inc. on behalf of World Institute of Pain.

Variation of Annual ET Determined from Water Budgets Across Rural Southeastern Basins Differing in Forest Types

NASA Astrophysics Data System (ADS)

Younger, S. E.; Jackson, C. R.

2017-12-01

In the Southeastern United States, evapotranspiration (ET) typically accounts for 60-70% of precipitation. Watershed and plot scale experiments show that evergreen forests have higher ET rates than hardwood forests and pastures. However, some plot experiments indicate that certain hardwood species have higher ET than paired evergreens. The complexity of factors influencing ET in mixed land cover watersheds makes identifying the relative influences difficult. Previous watershed scale studies have relied on regression to understand the influences or low flow analysis to indicate growing season differences among watersheds. Existing studies in the southeast investigating ET rates for watersheds with multiple forest cover types have failed to identify a significant forest type effect, but these studies acknowledge small sample sizes. Trends of decreasing streamflow have been recognized in the region and are generally attributed to five key factors, 1.) influences from multiple droughts, 2.) changes in distribution of precipitation, 3.) reforestation of agricultural land, 4.) increasing consumptive uses, or 5.) a combination of these and other factors. This study attempts to address the influence of forest type on long term average annual streamflow and on stream low flows. Long term annual ET rates were calculated as ET = P-Q for 46 USGS gaged basins with daily data for the 1982 - 2014 water years, >40% forest cover, and no large reservoirs. Land cover data was regressed against ET to describe the relationship between each of the forest types in the National Land Cover Database. Regression analysis indicates evergreen land cover has a positive relationship with ET while deciduous and total forest have a negative relationship with ET. Low flow analysis indicates low flows tend to be lower in watersheds with more evergreen cover, and that low flows increase with increasing deciduous cover, although these relationships are noisy. This work suggests considering forest cover type improves understanding of watershed scale ET at annual and seasonal levels which is consistent with historic paired watershed experiments and some plot scale data.

Diagnosing and dealing with multicollinearity.

PubMed

Schroeder, M A

1990-04-01

The purpose of this article was to increase nurse researchers' awareness of the effects of collinear data in developing theoretical models for nursing practice. Collinear data distort the true value of the estimates generated from ordinary least-squares analysis. Theoretical models developed to provide the underpinnings of nursing practice need not be abandoned, however, because they fail to produce consistent estimates over repeated applications. It is also important to realize that multicollinearity is a data problem, not a problem associated with misspecification of a theorectical model. An investigator must first be aware of the problem, and then it is possible to develop an educated solution based on the degree of multicollinearity, theoretical considerations, and sources of error associated with alternative, biased, least-square regression techniques. Decisions based on theoretical and statistical considerations will further the development of theory-based nursing practice.

Participation in Summer School and High School Graduation in the Sun Valley High School District

ERIC Educational Resources Information Center

Trujillo, Gabriel

2012-01-01

This study examines the effectiveness of a summer school credit recovery program in the Sun Valley High School District. Using logistic regression I assess the relationship between race, gender, course failure, school of origin and summer school participation for a sample of students that failed one or more classes in their first year of high…

Estimation of maximal oxygen uptake by bioelectrical impedance analysis.

PubMed

Stahn, Alexander; Terblanche, Elmarie; Grunert, Sven; Strobel, Günther

2006-02-01

Previous non-exercise models for the prediction of maximal oxygen uptake VO(2max) have failed to accurately discriminate cardiorespiratory fitness within large cohorts. The aim of the present study was to evaluate the feasibility of a completely indirect method for predicting VO(2max) that was based on bioelectrical impedance analysis (BIA) in 66 young, healthy fit men and women. Multiple, stepwise regression analysis was used to determine the usefulness of BIA and additional covariates to estimate VO(2max) (ml min(-1)). BIA was highly correlated to VO(2max) (r = 0.914; P < 0.001) and entered the regression equation first. The inclusion of gender and a physical activity rating further improved the model which accounted for 88% of the variance in VO(2max) and resulted in a relative standard error of the estimate (SEE) of 7.2%. Substantial agreement between the methods was confirmed by the fact that nearly all the differences were within +/-2 SD. Furthermore, in contrast to previously published non-exercise models, no trend of a reduction in prediction accuracy with increasing VO(2max) values was apparent. It was concluded that a non-exercise model based on BIA might be a rapid and useful technique to estimate VO(2max), when a direct test does not seem feasible. However, though the present results are useful to determine the viability of the method, further refinement of the BIA approach and its validation in a large, diverse population is needed before it can be applied to the clinical and epidemiological settings.

SEPARABLE FACTOR ANALYSIS WITH APPLICATIONS TO MORTALITY DATA

PubMed Central

Fosdick, Bailey K.; Hoff, Peter D.

2014-01-01

Human mortality data sets can be expressed as multiway data arrays, the dimensions of which correspond to categories by which mortality rates are reported, such as age, sex, country and year. Regression models for such data typically assume an independent error distribution or an error model that allows for dependence along at most one or two dimensions of the data array. However, failing to account for other dependencies can lead to inefficient estimates of regression parameters, inaccurate standard errors and poor predictions. An alternative to assuming independent errors is to allow for dependence along each dimension of the array using a separable covariance model. However, the number of parameters in this model increases rapidly with the dimensions of the array and, for many arrays, maximum likelihood estimates of the covariance parameters do not exist. In this paper, we propose a submodel of the separable covariance model that estimates the covariance matrix for each dimension as having factor analytic structure. This model can be viewed as an extension of factor analysis to array-valued data, as it uses a factor model to estimate the covariance along each dimension of the array. We discuss properties of this model as they relate to ordinary factor analysis, describe maximum likelihood and Bayesian estimation methods, and provide a likelihood ratio testing procedure for selecting the factor model ranks. We apply this methodology to the analysis of data from the Human Mortality Database, and show in a cross-validation experiment how it outperforms simpler methods. Additionally, we use this model to impute mortality rates for countries that have no mortality data for several years. Unlike other approaches, our methodology is able to estimate similarities between the mortality rates of countries, time periods and sexes, and use this information to assist with the imputations. PMID:25489353

Challenges to cognitive bases for an especial motor skill at the regulation baseball pitching distance.

PubMed

Simons, Jeffery P; Wilson, Jacob M; Wilson, Gabriel J; Theall, Stephen

2009-09-01

We tested expert baseball pitchers for evidence of especial skills at the regulation pitching distance. Seven college pitchers threw indoors to a target placed at 60.5 feet (18.44 m) and four closer and four further distances away. Accuracy at the regulation distance was significantly better than predicted by regression on the nonregulation distances (p < .02), indicating an especial skill effect emerged despite the absence of normal contextual cues. Self-efficacy data failed to support confidence as a mediating factor in especial skill effect. We concluded that cognitive theories fail to fully account for the patterns of observed data, and therefore theoretical explanations of the especial skills must address noncognitive aspects of motor learning and control.

Virtual stress testing of fracture stability in soldiers with severely comminuted tibial fractures.

PubMed

Petfield, Joseph L; Hayeck, Garry T; Kopperdahl, David L; Nesti, Leon J; Keaveny, Tony M; Hsu, Joseph R

2017-04-01

Virtual stress testing (VST) provides a non-invasive estimate of the strength of a healing bone through a biomechanical analysis of a patient's computed tomography (CT) scan. We asked whether VST could improve management of patients who had a tibia fracture treated with external fixation. In a retrospective case-control study of 65 soldier-patients who had tibia fractures treated with an external fixator, we performed VST utilizing CT scans acquired prior to fixator removal. The strength of the healing bone and the amount of tissue damage after application of an overload were computed for various virtual loading cases. Logistic regression identified computed outcomes with the strongest association to clinical events related to nonunion within 2 months after fixator removal. Clinical events (n = 9) were associated with a low tibial strength for compression loading (p < 0.05, AUC = 0.74) or a low proportion of failed cortical bone tissue for torsional loading (p < 0.005, AUC = 0.84). Using post-hoc thresholds of a compressive strength of four times body-weight and a proportional of failed cortical bone tissue of 5%, the test identified all nine patients who failed clinically (100% sensitivity; 40.9% positive predictive value) and over three fourths of those (43 of 56) who progressed to successful healing (76.8% specificity; 100% negative predictive value). In this study, VST identified all patients who progressed to full, uneventful union after fixator removal; thus, we conclude that this new test has the potential to provide a quantitative, objective means of identifying tibia-fracture patients who can safely resume weight bearing. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:805-811, 2017. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Identification of a genetic variant associated with rotator cuff repair healing.

PubMed

Tashjian, Robert Z; Granger, Erin K; Zhang, Yue; Teerlink, Craig C; Cannon-Albright, Lisa A

2016-06-01

A familial and genetic predisposition for the development of rotator cuff tearing has been identified. The purpose of this study was to determine if a familial predisposition exists for healing after rotator cuff repair and if the reported significant association with a single-nucleotide polymorphism (SNP) in the ESRRB gene is present in patients who fail to heal. The study recruited 72 patients undergoing arthroscopic rotator cuff repair for a full-thickness posterosuperior tear. Magnetic resonance imaging studies were performed at a minimum of 1 year postoperatively (average, 2.6 years). Healing failures were classified as lateral or medial. Self-reported family history of rotator cuff tearing data and genome-wide genotypes were available. Characteristics of cases with and without a family history of rotator cuff tearing were compared, and a comparison of the frequency of SNP 1758384 (in ESRRB) was performed between patients who healed and those who failed to heal. Of the rotator cuff repairs, 42% failed to heal; 42% of patients reported a family history of rotator cuff tear. Multivariate regression analysis showed a significant association between familiality and overall healing failure (medial and lateral failures) (P = .036) and lateral failures independently (P = .006). An increased risk for the presence of a rare allele for SNP rs17583842 was present in lateral failures compared with those that healed (P = .005). Individuals with a family history of rotator cuff tearing were more likely to have repair failures. Significant association of a SNP variant in the ESRRB gene was also observed with lateral failure. Copyright © 2016 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Cognition and screening for hearing loss in nursing home residents.

PubMed

Jupiter, Tina

2012-10-01

To compare hearing screening results using pure tones and distortion product otoacoustic emissions (DPOAEs) with nursing home residents who have dementia and explore the relationship of hearing impairment and cognitive function using the Mini- Mental Status Evaluation (MMSE). A correlational design was implemented to evaluate residents in a large inner city nursing home. One hundred one nursing home residents 65-108 years. DPOAEs and pure tone screenings were conducted at 30 dB HL and 40 dB HL at 1, 2, and 3 kHz. Pure tone thresholds at 1, 2, and 3 kHz were obtained. The MMSE was administered to all participants. Results showed that all residents failed the DPOAE screen, 97.1% failed at 30 dB HL, and 90.0% failed at 40 dB HL. Kendall's tau, phi correlation, linear by linear association, and χ(2) results indicated no significant relationship for any of the screening protocols and cognitive status other than a significant finding with left ear screening at 40 dB HL. Logistic regression analysis indicated that individuals who passed the screen had better MMSE scores. Results of the t test and Mann-Whitney U test revealed a significant difference in cognitive function for residents with a mild hearing loss compared with those with a more significant hearing loss. For screening nursing home residents, 40 dB HL screening level or DPOAEs can be used. The significant finding that residents with greater than a mild hearing loss have poorer cognitive function reinforces the importance of identifying residents with a hearing loss and providing rehabilitation and follow-up. Copyright © 2012 American Medical Directors Association, Inc. Published by Elsevier Inc. All rights reserved.

Testing safety eyewear: how frame and lens design affect lens retention.

PubMed

McMahon, Janice M; Beckerman, Stephen

2007-02-01

The aim of this study was to determine the role that frame and lens design play in lens retention during high-impact testing of safety eyewear that advertises conformance to the performance-based ANSI Z87.1-2003 standard. A total of 75 Z87 safety eyeglass frames (3 each of 25 frame models) were used in this study, procured from 5 of the leading U.S. safety frame manufacturers. Frames were fitted by an independent laboratory with 2.0-mm plano polycarbonate lenses in compliance with ANSI Z87.1-2003. Finished spectacles were sent to a subsequent laboratory testing facility where each frame was subjected to both high-mass and oblique-incidence high-velocity impacts to determine frame characteristics that were most highly associated with testing failure. Among the frame and lens parameters that were considered in this analysis were the A and B dimensions, effective diameter, distance between lenses, bridge type, frame material, bevel type, and frame cost. Certain variables were controlled for by maintaining consistency among all spectacle pairs, e.g., lens prescription, center thickness, and edge thickness. Multiple logistic regression was used to control potential confounding variables and to develop the best combination of them for predictive value. Of 25 separate frame models assessed, 10 passed both high-mass and high-velocity impact testing, i.e., none of the 3 frame/lens samples failed. Of the models that failed, 13 failures were caused by high-velocity testing, 1 by high-mass testing, and 1 failed both high-mass and high-velocity testing. None of the 15 spectacles with the SprinGuardtrade mark (Hilco, Plainville, Massachusetts) bevel design failed, although these were proprietary to 1 manufacturer and included only 5 frame models. Two spectacle designs (6 individual frames) incorporated an inverted bevel design of which 3 of the frames failed impact testing. Controlling for drop ball velocity among the 54 remaining standard "V" bevel spectacle pairs, the odds of failure were about 8 to 9 times higher for metal frames than Zylonite frames (odds ratio [OR], 8.5; 95% confidence interval [CI], 1.4 to 52.3; P = 0.02), and the odds of failure were about 4 times higher for lens effective diameters of less than 50 mm than for lens effective diameters more than 50 mm (OR, 4.1; 95% CI, 1.2 to 14.8; P = 0.03). Among our sample of safety spectacles, failure from high-mass impact resistance testing rarely occurred. No spectacles with the SprinGuard bevel design failed in our analysis, but this was limited to a small sample size from a single manufacturer. Among our sample of 54 spectacle pairs with a v-bevel design, metal frame material and an effective diameter of less than 50 mm were the strongest predictors of failure relative to high-velocity impact testing with a 45 degrees temporal angle projectile.

Fluoroscopic tumor tracking for image-guided lung cancer radiotherapy

NASA Astrophysics Data System (ADS)

Lin, Tong; Cerviño, Laura I.; Tang, Xiaoli; Vasconcelos, Nuno; Jiang, Steve B.

2009-02-01

Accurate lung tumor tracking in real time is a keystone to image-guided radiotherapy of lung cancers. Existing lung tumor tracking approaches can be roughly grouped into three categories: (1) deriving tumor position from external surrogates; (2) tracking implanted fiducial markers fluoroscopically or electromagnetically; (3) fluoroscopically tracking lung tumor without implanted fiducial markers. The first approach suffers from insufficient accuracy, while the second may not be widely accepted due to the risk of pneumothorax. Previous studies in fluoroscopic markerless tracking are mainly based on template matching methods, which may fail when the tumor boundary is unclear in fluoroscopic images. In this paper we propose a novel markerless tumor tracking algorithm, which employs the correlation between the tumor position and surrogate anatomic features in the image. The positions of the surrogate features are not directly tracked; instead, we use principal component analysis of regions of interest containing them to obtain parametric representations of their motion patterns. Then, the tumor position can be predicted from the parametric representations of surrogates through regression. Four regression methods were tested in this study: linear and two-degree polynomial regression, artificial neural network (ANN) and support vector machine (SVM). The experimental results based on fluoroscopic sequences of ten lung cancer patients demonstrate a mean tracking error of 2.1 pixels and a maximum error at a 95% confidence level of 4.6 pixels (pixel size is about 0.5 mm) for the proposed tracking algorithm.

Evaluation of the efficiency of continuous wavelet transform as processing and preprocessing algorithm for resolution of overlapped signals in univariate and multivariate regression analyses; an application to ternary and quaternary mixtures

NASA Astrophysics Data System (ADS)

Hegazy, Maha A.; Lotfy, Hayam M.; Mowaka, Shereen; Mohamed, Ekram Hany

2016-07-01

Wavelets have been adapted for a vast number of signal-processing applications due to the amount of information that can be extracted from a signal. In this work, a comparative study on the efficiency of continuous wavelet transform (CWT) as a signal processing tool in univariate regression and a pre-processing tool in multivariate analysis using partial least square (CWT-PLS) was conducted. These were applied to complex spectral signals of ternary and quaternary mixtures. CWT-PLS method succeeded in the simultaneous determination of a quaternary mixture of drotaverine (DRO), caffeine (CAF), paracetamol (PAR) and p-aminophenol (PAP, the major impurity of paracetamol). While, the univariate CWT failed to simultaneously determine the quaternary mixture components and was able to determine only PAR and PAP, the ternary mixtures of DRO, CAF, and PAR and CAF, PAR, and PAP. During the calculations of CWT, different wavelet families were tested. The univariate CWT method was validated according to the ICH guidelines. While for the development of the CWT-PLS model a calibration set was prepared by means of an orthogonal experimental design and their absorption spectra were recorded and processed by CWT. The CWT-PLS model was constructed by regression between the wavelet coefficients and concentration matrices and validation was performed by both cross validation and external validation sets. Both methods were successfully applied for determination of the studied drugs in pharmaceutical formulations.

An Alternative Flight Software Trigger Paradigm: Applying Multivariate Logistic Regression to Sense Trigger Conditions Using Inaccurate or Scarce Information

NASA Technical Reports Server (NTRS)

Smith, Kelly M.; Gay, Robert S.; Stachowiak, Susan J.

2013-01-01

In late 2014, NASA will fly the Orion capsule on a Delta IV-Heavy rocket for the Exploration Flight Test-1 (EFT-1) mission. For EFT-1, the Orion capsule will be flying with a new GPS receiver and new navigation software. Given the experimental nature of the flight, the flight software must be robust to the loss of GPS measurements. Once the high-speed entry is complete, the drogue parachutes must be deployed within the proper conditions to stabilize the vehicle prior to deploying the main parachutes. When GPS is available in nominal operations, the vehicle will deploy the drogue parachutes based on an altitude trigger. However, when GPS is unavailable, the navigated altitude errors become excessively large, driving the need for a backup barometric altimeter to improve altitude knowledge. In order to increase overall robustness, the vehicle also has an alternate method of triggering the parachute deployment sequence based on planet-relative velocity if both the GPS and the barometric altimeter fail. However, this backup trigger results in large altitude errors relative to the targeted altitude. Motivated by this challenge, this paper demonstrates how logistic regression may be employed to semi-automatically generate robust triggers based on statistical analysis. Logistic regression is used as a ground processor pre-flight to develop a statistical classifier. The classifier would then be implemented in flight software and executed in real-time. This technique offers improved performance even in the face of highly inaccurate measurements. Although the logistic regression-based trigger approach will not be implemented within EFT-1 flight software, the methodology can be carried forward for future missions and vehicles.

An Alternative Flight Software Paradigm: Applying Multivariate Logistic Regression to Sense Trigger Conditions using Inaccurate or Scarce Information

NASA Technical Reports Server (NTRS)

Smith, Kelly; Gay, Robert; Stachowiak, Susan

2013-01-01

In late 2014, NASA will fly the Orion capsule on a Delta IV-Heavy rocket for the Exploration Flight Test-1 (EFT-1) mission. For EFT-1, the Orion capsule will be flying with a new GPS receiver and new navigation software. Given the experimental nature of the flight, the flight software must be robust to the loss of GPS measurements. Once the high-speed entry is complete, the drogue parachutes must be deployed within the proper conditions to stabilize the vehicle prior to deploying the main parachutes. When GPS is available in nominal operations, the vehicle will deploy the drogue parachutes based on an altitude trigger. However, when GPS is unavailable, the navigated altitude errors become excessively large, driving the need for a backup barometric altimeter to improve altitude knowledge. In order to increase overall robustness, the vehicle also has an alternate method of triggering the parachute deployment sequence based on planet-relative velocity if both the GPS and the barometric altimeter fail. However, this backup trigger results in large altitude errors relative to the targeted altitude. Motivated by this challenge, this paper demonstrates how logistic regression may be employed to semi-automatically generate robust triggers based on statistical analysis. Logistic regression is used as a ground processor pre-flight to develop a statistical classifier. The classifier would then be implemented in flight software and executed in real-time. This technique offers improved performance even in the face of highly inaccurate measurements. Although the logistic regression-based trigger approach will not be implemented within EFT-1 flight software, the methodology can be carried forward for future missions and vehicles

An Alternative Flight Software Trigger Paradigm: Applying Multivariate Logistic Regression to Sense Trigger Conditions using Inaccurate or Scarce Information

NASA Technical Reports Server (NTRS)

Smith, Kelly M.; Gay, Robert S.; Stachowiak, Susan J.

2013-01-01

In late 2014, NASA will fly the Orion capsule on a Delta IV-Heavy rocket for the Exploration Flight Test-1 (EFT-1) mission. For EFT-1, the Orion capsule will be flying with a new GPS receiver and new navigation software. Given the experimental nature of the flight, the flight software must be robust to the loss of GPS measurements. Once the high-speed entry is complete, the drogue parachutes must be deployed within the proper conditions to stabilize the vehicle prior to deploying the main parachutes. When GPS is available in nominal operations, the vehicle will deploy the drogue parachutes based on an altitude trigger. However, when GPS is unavailable, the navigated altitude errors become excessively large, driving the need for a backup barometric altimeter. In order to increase overall robustness, the vehicle also has an alternate method of triggering the drogue parachute deployment based on planet-relative velocity if both the GPS and the barometric altimeter fail. However, this velocity-based trigger results in large altitude errors relative to the targeted altitude. Motivated by this challenge, this paper demonstrates how logistic regression may be employed to automatically generate robust triggers based on statistical analysis. Logistic regression is used as a ground processor pre-flight to develop a classifier. The classifier would then be implemented in flight software and executed in real-time. This technique offers excellent performance even in the face of highly inaccurate measurements. Although the logistic regression-based trigger approach will not be implemented within EFT-1 flight software, the methodology can be carried forward for future missions and vehicles.

The prevalence and effects of mood disorders on work performance in a nationally representative sample of US workers

PubMed Central

Kessler, Ronald C.; Akiskal, Hagop S.; Ames, Minnie; Birnbaum, Howard; Greenberg, Paul; Hirschfeld, Robert M.A.; Jin, Robert; Merikangas, Kathleen R.; Wang, Philip S.

2007-01-01

OBJECTIVE Research on the workplace costs of mood disorders has focused largely on major depressive episodes (MDE). Bipolar disorder (BPD) has been overlooked both by failing to distinguish MDE due to major depressive disorder (MDD) versus BPD and by failing to evaluate the workplace costs of mania and hypomania. METHOD The National Comorbidity Survey Replication (NCS-R) assessed DSM-IV MDD and BPD with the WHO Composite International Diagnostic Interview (CIDI) and assessed work impairment with the WHO Health and Work Performance Questionnaire (HPQ). Regression analysis of MDD and BPD predicting HPQ among workers (n = 3378) was used to estimate the workplace costs of mood disorders. RESULTS 1.1% of workers met CIDI criteria for 12-month BPD (bipolar I or bipolar II) and 6.4% for 12-month MDD. BPD was associated with 65.5 and MDD with 27.2 annual lost workdays per ill worker. Subgroup analysis showed that the higher work loss associated with BPD than MDD is due to more severe and persistent MDE in BPD than MDD rather than to stronger effects of mania-hypomania than depression. Annual human capital loss per ill worker was estimated at $9619 for BPD and $4426 for MDD. Annual projections to the US labor force were $14.1 billion for BPD and $36.6 billion for MDD. CONCLUSIONS Employer interest in the workplace costs of mood disorders should be broadened beyond MDD to include BPD. Effectiveness trials are needed to study the return on employer investment of coordinated programs for workplace screening and treatment of BPD and MDD. PMID:16946181

Changes in esophageal motility after endoscopic submucosal dissection for superficial esophageal cancer: a high-resolution manometry study.

PubMed

Takahashi, K; Sato, Y; Takeuchi, M; Sato, H; Nakajima, N; Ikarashi, S; Hayashi, K; Mizuno, K-I; Honda, Y; Hashimoto, S; Yokoyama, J; Terai, S

2017-11-01

The effect of endoscopic submucosal dissection (ESD) on esophageal motility remains unknown. Therefore, the aim of this study is to elucidate changes in esophageal motility after ESD along with the cause of dysphagia using high-resolution manometry (HRM). This is a before-and-after trial of the effect of ESD on the esophageal motility. Twenty patients who underwent ESD for superficial esophageal carcinoma were enrolled in this study. Patients filled out a questionnaire about dysphagia and underwent HRM before and after ESD. Results before and after ESD were compared. Data were obtained from 19 patients. The number of patients who complained of dysphagia before and after ESD was 1/19 (5.3%) and 6/19 (31.6%), respectively (P = 0.131). Scores from the five-point Likert scale before and after ESD were 0.1 ± 0.5 and 1.0 ± 1.6, respectively (P = 0.043). The distal contractile integral (DCI) before and after ESD and the number of failed, weak, or fragmented contractions were not significantly different. However, in five patients with circumferential ESD, DCI was remarkably decreased and the frequency of fail, weak, or fragmented contractions increased. Univariate regression analysis showed a relatively strong inverse correlation of ΔDCI with the circumferential mucosal defect ratio {P < 0.01, standardized regression coefficient (r) = -0.65}, the number of stricture preventions (P < 0.01, r = -0.601), and the number of stricture resolutions (P < 0.01, r = -0.77). This HRM study showed that impairment of esophageal motility could be caused by ESD. The impairment of esophageal motility was conspicuous, especially in patients with circumferential ESD and subsequent procedures such as endoscopic triamcinolone injection and endoscopic balloon dilatation. Impaired esophageal motility after ESD might explain dysphagia. © The Authors 2017. Published by Oxford University Press on behalf of International Society for Diseases of the Esophagus. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Factors affecting outcome of triceps motor branch transfer for isolated axillary nerve injury.

PubMed

Lee, Joo-Yup; Kircher, Michelle F; Spinner, Robert J; Bishop, Allen T; Shin, Alexander Y

2012-11-01

Triceps motor branch transfer has been used in upper brachial plexus injury and is potentially effective for isolated axillary nerve injury in lieu of sural nerve grafting. We evaluated the functional outcome of this procedure and determined factors that influenced the outcome. A retrospective chart review was performed of 21 patients (mean age, 38 y; range, 16-79 y) who underwent triceps motor branch transfer for the treatment of isolated axillary nerve injury. Deltoid muscle strength was evaluated using the modified British Medical Research Council grading at the last follow-up (mean, 21 mo; range, 12-41 mo). The following variables were analyzed to determine whether they affected the outcome of the nerve transfer: the age and sex of the patient, delay from injury to surgery, body mass index (BMI), severity of trauma, and presence of rotator cuff lesions. The Spearman correlation coefficient and multiple linear regression were performed for statistical analysis. The average Medical Research Council grade of deltoid muscle strength was 3.5 ± 1.1. Deltoid muscle strength correlated with the age of the patient, delay from injury to surgery, and BMI of the patient. Five patients failed to achieve more than M3 grade. Among them, 4 patients were older than 50 years and 1 was treated 14 months after injury. In the multiple linear regression model, the delay from injury to surgery, age of the patient, and BMI of the patient were the important factors, in that order, that affected the outcome of this procedure. Isolated axillary nerve injury can be treated successfully with triceps motor branch transfer. However, outstanding outcomes are not universal, with one fourth failing to achieve M3 strength. The outcome of this procedure is affected by the delay from injury to surgery and the age and BMI of the patient. Copyright © 2012 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

Mycophenolate mofetil after methotrexate failure or intolerance in the treatment of scleritis and uveitis.

PubMed

Sobrin, Lucia; Christen, William; Foster, C Stephen

2008-08-01

To evaluate the outcomes of treatment with mycophenolate mofetil in patients with scleritis and uveitis refractory to or intolerant of methotrexate. Retrospective noncomparative case series. Eighty-five patients with scleritis and/or uveitis who failed with or did not tolerate methotrexate and were subsequently treated with mycophenolate mofetil between 1998 and 2006. We reviewed medical records of patients who were treated with mycophenolate mofetil after methotrexate intolerance or failure at one tertiary uveitis referral practice. We recorded dose and duration of methotrexate and mycophenolate mofetil therapy, inflammation grade, Snellen visual acuity (VA), use of other immunomodulatory therapy, and adverse events. Multivariate logistic regression was used to identify factors associated with inflammation control. Control of inflammation, steroid-sparing effect, VA, and adverse effects were assessed. Inflammation was controlled with mycophenolate mofetil in 47 patients (55%), with 5 achieving durable remission off all medication. In multivariate logistic regression analysis that adjusted for gender and age, the odds of inflammation control were lower for patients with scleritis (odds ratio [OR], 0.19; 95% confidence interval [CI], 0.04-0.93; P = 0.04) than for patients without scleritis. Among patients without scleritis, the odds of inflammation control were lower for patients with juvenile idiopathic arthritis (JIA)-associated uveitis (OR, 0.14; CI, 0.02-0.81, P = 0.03) compared to patients without JIA-associated uveitis. Eight of the 11 patients (73%) who were taking concomitant prednisone were able to taper their dose to <10 mg daily. Visual acuity declined in a greater percentage of patients who were unresponsive to mycophenolate mofetil (29%) compared with that of patients who responded to mycophenolate mofetil (9%). Side effects requiring discontinuation of mycophenolate mofetil occurred in 18 patients (21%). Mycophenolate mofetil was effective in controlling inflammation in approximately half of the patients who had previously failed with or did not tolerate methotrexate. The odds of inflammation control were less in patients with the diagnoses of scleritis and JIA.

T-tubule disease: Relationship between t-tubule organization and regional contractile performance in human dilated cardiomyopathy.

PubMed

Crossman, David J; Young, Alistair A; Ruygrok, Peter N; Nason, Guy P; Baddelely, David; Soeller, Christian; Cannell, Mark B

2015-07-01

Evidence from animal models suggest that t-tubule changes may play an important role in the contractile deficit associated with heart failure. However samples are usually taken at random with no regard as to regional variability present in failing hearts which leads to uncertainty in the relationship between contractile performance and possible t-tubule derangement. Regional contraction in human hearts was measured by tagged cine MRI and model fitting. At transplant, failing hearts were biopsy sampled in identified regions and immunocytochemistry was used to label t-tubules and sarcomeric z-lines. Computer image analysis was used to assess 5 different unbiased measures of t-tubule structure/organization. In regions of failing hearts that showed good contractile performance, t-tubule organization was similar to that seen in normal hearts, with worsening structure correlating with the loss of regional contractile performance. Statistical analysis showed that t-tubule direction was most highly correlated with local contractile performance, followed by the amplitude of the sarcomeric peak in the Fourier transform of the t-tubule image. Other area based measures were less well correlated. We conclude that regional contractile performance in failing human hearts is strongly correlated with the local t-tubule organization. Cluster tree analysis with a functional definition of failing contraction strength allowed a pathological definition of 't-tubule disease'. The regional variability in contractile performance and cellular structure is a confounding issue for analysis of samples taken from failing human hearts, although this may be overcome with regional analysis by using tagged cMRI and biopsy mapping. Copyright © 2015 Elsevier Ltd. All rights reserved.

Childhood growth and development associated with need for full-time special education at school age.

PubMed

Mannerkoski, Minna; Aberg, Laura; Hoikkala, Marianne; Sarna, Seppo; Kaski, Markus; Autti, Taina; Heiskala, Hannu

2009-01-01

To explore how growth measurements and attainment of developmental milestones in early childhood reflect the need for full-time special education (SE). After stratification in this population-based study, 900 pupils in full-time SE groups (age-range 7-16 years, mean 12 years 8 months) at three levels and 301 pupils in mainstream education (age-range 7-16, mean 12 years 9 months) provided data on height and weight from birth to age 7 years and head circumference to age 1 year. Developmental screening was evaluated from age 1 month to 48 months. Statistical methods included a general linear model (growth measurements), binary logistic regression analysis (odds ratios for growth), and multinomial logistic regression analysis (odds ratios for developmental milestones). At 1 year, a 1 standard deviation score (SDS) decrease in height raised the probability of SE placement by 40%, and a 1 SDS decrease in head size by 28%. In developmental screening, during the first months of life the gross motor milestones, especially head support, differentiated the children at levels 0-3. Thereafter, the fine motor milestones and those related to speech and social skills became more important. Children whose growth is mildly impaired, though in the normal range, and who fail to attain certain developmental milestones have an increased probability for SE and thus a need for special attention when toddlers age. Similar to the growth curves, these children seem to have consistent developmental curves (patterns).

Serum estradiol does not differentiate stress, mixed and urge incontinent women around menopause. A report from the Women's Health in the Lund Area (WHILA) study.

PubMed

Hamer, Maria Andrada; Källén, Karin; Lidfeldt, Jonas; Samsioe, Göran; Teleman, Pia

2011-11-01

To outline serum estradiol levels in perimenopausal women with stress, mixed or urge incontinence. We believe the majority of urgency symptoms in perimenopausal women to be caused by a pelvic floor dysfunction and a hypermobility of the bladder neck. If this is the case, there would be no difference in estradiol levels between the groups. University hospital. In the observational Women's Health in the Lund Area study, a subset of 400/2221 women reporting urinary incontinence completed a detailed questionnaire regarding lower urinary tract symptoms and had their serum steroid hormone levels measured. Statistical analyses were made by Chi-square test, nonparametrical tests, ANOVA, multi- and univariate logistic regression analysis. Stress incontinence was reported by 196, mixed incontinence by 153 and urge incontinence by 43 women; in 369, serumestradiol values were available. Serum estradiol did not differ significantly between stress incontinent (median 49.5 pmo/l, range 2.63-875.4), urge incontinent (median 31.6 pmol/l, range 2.63-460.7) or mixed incontinent women (median 35.5 pmol/l, range 2.63-787.9, p=0.62). Logistic regression analysis correcting for age, parity, hormonal status, smoking, hysterectomy and BMI also failed to show any difference in estradiol levels between the groups (p=0.41-0.58). No significant differences in serum estradiol levels between stress, mixed or urge incontinent perimenopausal women could be demonstrated. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Prostate cancer mortality in Serbia, 1991-2010: a joinpoint regression analysis.

PubMed

Ilic, Milena; Ilic, Irena

2016-06-01

The aim of this descriptive epidemiological study was to analyze the mortality trend of prostate cancer in Serbia (excluding the Kosovo and Metohia) from 1991 to 2010. The age-standardized prostate cancer mortality rates (per 100 000) were calculated by direct standardization, using the World Standard Population. Average annual percentage of change (AAPC) and the corresponding 95% confidence interval (CI) was computed for trend using the joinpoint regression analysis. Significantly increased trend in prostate cancer mortality was recorded in Serbia continuously from 1991 to 2010 (AAPC = +2.2, 95% CI = 1.6-2.9). Mortality rates for prostate cancer showed a significant upward trend in all men aged 50 and over: AAPC (95% CI) was +1.9% (0.1-3.8) in aged 50-59 years, +1.7% (0.9-2.6) in aged 60-69 years, +2.0% (1.2-2.9) in aged 70-79 years and +3.5% (2.4-4.6) in aged 80 years and over. According to comparability test, prostate cancer mortality trends in majority of age groups were parallel (final selected model failed to reject parallelism, P > 0.05). The increasing prostate cancer mortality trend implies the need for more effective measures of prevention, screening and early diagnosis, as well as prostate cancer treatment in Serbia. © The Author 2015. Published by Oxford University Press on behalf of Faculty of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Canadian firearms legislation and effects on homicide 1974 to 2008.

PubMed

Langmann, Caillin

2012-08-01

Canada has implemented legislation covering all firearms since 1977 and presents a model to examine incremental firearms control. The effect of legislation on homicide by firearm and the subcategory, spousal homicide, is controversial and has not been well studied to date. Legislative effects on homicide and spousal homicide were analyzed using data obtained from Statistics Canada from 1974 to 2008. Three statistical methods were applied to search for any associated effects of firearms legislation. Interrupted time series regression, ARIMA, and Joinpoint analysis were performed. Neither were any significant beneficial associations between firearms legislation and homicide or spousal homicide rates found after the passage of three Acts by the Canadian Parliament--Bill C-51 (1977), C-17 (1991), and C-68 (1995)--nor were effects found after the implementation of licensing in 2001 and the registration of rifles and shotguns in 2003. After the passage of C-68, a decrease in the rate of the decline of homicide by firearm was found by interrupted regression. Joinpoint analysis also found an increasing trend in homicide by firearm rate post the enactment of the licensing portion of C-68. Other factors found to be associated with homicide rates were median age, unemployment, immigration rates, percentage of population in low-income bracket, Gini index of income equality, population per police officer, and incarceration rate. This study failed to demonstrate a beneficial association between legislation and firearm homicide rates between 1974 and 2008.

Magnetic resonance spectroscopic determination of a neuronal and axonal marker in white matter predicts reversibility of deficits in secondary normal pressure hydrocephalus

PubMed Central

Shiino, A; Nishida, Y; Yasuda, H; Suzuki, M; Matsuda, M; Inubushi, T

2004-01-01

Background: Normal pressure hydrocephalus (NPH) is considered to be a treatable form of dementia, because cerebrospinal fluid (CSF) shunting can lessen symptoms. However, neuroimaging has failed to predict when shunting will be effective. Objective: To investigate whether 1H (proton) magnetic resonance (MR) spectroscopy could predict functional outcome in patients after shunting. Methods: Neurological state including Hasegawa's dementia scale, gait, continence, and the modified Rankin scale were evaluated in 21 patients with secondary NPH who underwent ventriculo-peritoneal shunting. Outcomes were measured postoperatively at one and 12 months and were classified as excellent, fair, or poor. MR spectra were obtained from left hemispheric white matter. Results: Significant preoperative differences in N-acetyl aspartate (NAA)/creatine (Cr) and NAA/choline (Cho) were noted between patients with excellent and poor outcome at one month (p = 0.0014 and 0.0036, respectively). Multiple regression analysis linked higher preoperative NAA/Cr ratio, gait score, and modified Rankin scale to better one month outcome. Predictive value, sensitivity, and specificity for excellent outcome following shunting were 95.2%, 100%, and 87.5%. Multiple regression analysis indicated that NAA/Cho had the best predictive value for one year outcome (p = 0.0032); predictive value, sensitivity, and specificity were 89.5%, 90.0%, and 88.9%. Conclusions: MR spectroscopy predicted long term post-shunting outcomes in patients with secondary NPH, and it would be a useful assessment tool before lumbar drainage. PMID:15258216

Performance of a fail-safe system to follow up abnormal mammograms in primary care.

PubMed

Grossman, Ellie; Phillips, Russell S; Weingart, Saul N

2010-09-01

Missed and delayed breast cancer diagnoses are major sources of potential harm to patients and medical malpractice liability in the United States. Follow-up of abnormal mammogram results is an essential but challenging component of safe breast care. To explore the value of an inexpensive method to follow up abnormal test results, we examined a paper-based fail-safe system. We examined a fail-safe system used to follow up abnormal mammograms at a primary care practice at an urban teaching hospital. We analyzed all abnormal mammogram reports and clinicians' responses to follow-up reminders. We characterized potential lapses identified in this system and used regression models to identify patient, provider, and test result characteristics associated with such lapses. Clinicians responded to fail-safe reminders for 92% of 948 abnormal mammograms. Clinicians reported that they were unaware of the abnormal result in 8% of cases and that there was no follow-up plan in place for 3% of cases. Clinicians with more years of experience were more likely to be aware of the abnormal result (odds of being unaware per incremental year in practice, 0.92; 95% confidence interval, 0.88-0.97) and were more likely to have a follow-up plan. A paper-based fail-safe system for abnormal mammograms is feasible in a primary care practice. However, special care is warranted to ensure full clinician adherence and address staff transitions and trainee-related issues.

Failure Analysis of Space Shuttle Orbiter Valve Poppet

NASA Technical Reports Server (NTRS)

Russell, Rick

2010-01-01

The poppet failed during STS-126 due to fatigue cracking that most likely was initiated during MDC ground-testing. This failure ultimately led to the discovery that the cracking problem was a generic issue effecting numerous poppets throughout the Shuttle program's history. This presentation has focused on the laboratory analysis of the failed hardware, but this analysis was only one aspect of a comprehensive failure investigation. One critical aspect of the overall investigation was modeling of the fluid flow through this valve to determine the possible sources of cyclic loading. This work has led to the conclusion that the poppets are failing due to flow-induced vibration.

Exploring the issue of failure to fail in a nursing program.

PubMed

Larocque, Sylvie; Luhanga, Florence Loyce

2013-05-18

A study using a qualitative descriptive design was undertaken to explore the issue of "failure to fail" in a nursing program. Individual in-depth interviews were conducted with nursing university faculty members, preceptors, and faculty advisors (n=13). Content analysis was used to analyze the data. Results indicate that: (a) failing a student is a difficult process; (b) both academic and emotional support are required for students and preceptors and faculty advisors; (c) there are consequences for programs, faculty, and students when a student has failed a placement; (d) at times, personal, professional, and structural reasons exist for failing to fail a student; and (e) the reputation of the professional program can be diminished as a result of failing to fail a student. Recommendations for improving assessment, evaluation, and intervention with a failing student include documentation, communication, and support. These findings have implications for improving the quality of clinical experiences.

User-perceived reliability of unrepairable shared protection systems with functionally identical units

NASA Astrophysics Data System (ADS)

Ozaki, Hirokazu; Kara, Atsushi; Cheng, Zixue

2012-05-01

In this article, we investigate the reliability of M-for-N (M:N) shared protection systems. We focus on the reliability that is perceived by an end user of one of N units. We assume that any failed unit is instantly replaced by one of the M units (if available). We describe the effectiveness of such a protection system in a quantitative manner under the condition that the failed units are not repairable. Mathematical analysis gives the closed-form solution of the reliability and mean time to failure (MTTF). We also analyse several numerical examples of the reliability and MTTF. This result can be applied, for example, to the analysis and design of an integrated circuit consisting of redundant backup components. In such a device, repairing a failed component is unrealistic. The analysis provides useful information for the design for general shared protection systems in which the failed units are not repaired.

The Weakness of Stern Alcohol Control Policies.

PubMed

Poikolainen, Kari

2016-01-01

To test the total consumption model claiming that alcohol-related ill health can best be diminished by a policy of severe restrictions and high price. The associations between an index measuring the severity of the alcohol policy, total alcohol consumption and number of disability-adjusted life years (DALYs) lost due to alcohol were compared in 30 OECD countries in 2005. No significant correlations were found between alcohol policy index, alcohol consumption and the number of DALYs due to alcohol use. In regression analysis, alcohol policy index and alcohol consumption were not related to alcohol-related DALYs. Excise tax rate was not related to alcohol-related DALYs (25 countries with tax rate data). These findings suggest that the total consumption model fails. Alcohol-related ill health seems to be mainly due to alcohol dependence, both clinical and subclinical, not to moderate drinking. © The Author 2015. Medical Council on Alcohol and Oxford University Press. All rights reserved.

Threshold and resilience management of coupled urbanization and water environmental system in the rapidly changing coastal region.

PubMed

Li, Yangfan; Li, Yi; Wu, Wei

2016-01-01

The concept of thresholds shows important implications for environmental and resource management. Here we derived potential landscape thresholds which indicated abrupt changes in water quality or the dividing points between exceeding and failing to meet national surface water quality standards for a rapidly urbanizing city on the Eastern Coast in China. The analysis of landscape thresholds was based on regression models linking each of the seven water quality variables to each of the six landscape metrics for this coupled land-water system. We found substantial and accelerating urban sprawl at the suburban areas between 2000 and 2008, and detected significant nonlinear relations between water quality and landscape pattern. This research demonstrated that a simple modeling technique could provide insights on environmental thresholds to support more-informed decision making in land use, water environmental and resilience management. Copyright © 2015 Elsevier Ltd. All rights reserved.

Predictors of invalid neuropsychological test performance after traumatic brain injury.

PubMed

Moore, Bret A; Donders, Jacobus

2004-10-01

To investigate the usefulness of the Test of Memory Malingering (TOMM) and the California Verbal Learning Test-Second Edition (CVLT-II) in assessing invalid test performance after traumatic brain injury (TBI). Consecutive 3-year series of rehabilitation referrals (n = 132). Percentage of participants who failed validity criteria was determined. Hierarchical logistic regression analysis and odds ratios were used to identify predictors of invalid test performance. Twenty patients (15%) performed in the invalid range when held to a priori specified criteria for invalid test performance (i.e. TOMM <45/50 on Trial 2 or CVLT-II <15/16 on Forced-Choice recognition trial). Both psychiatric history and financial compensation seeking were associated with an almost 4-fold increase in likelihood of invalid responding. The TOMM and CVLT-II are sensitive to the potential impact of current financial compensation seeking and prior psychiatric history on neuropsychological test performance after TBI.

[Teaching practices and learning strategies in health careers].

PubMed

Carrasco Z, Constanza; Pérez V, Cristhian; Torres A, Graciela; Fasce H, Eduardo

2016-09-01

Medical Education, according to the constructivist education paradigm, puts students as the protagonists of the teaching and learning process. It demands changes in the practice of teaching. However, it is unclear whether this new model is coherent with the teachers’ ways to cope with learning. To analyze the relationship between teaching practices and learning strategies among teachers of health careers in Chilean universities. The Teaching Practices Questionnaire and Learning Strategies Inventory of Schmeck were applied to 200 teachers aged 24 to 72 years (64% females). Teachers use different types of teaching practices. They commonly use deep and elaborative learning strategies. A multiple regression analysis showed that learning strategies had a 13% predictive value to identify student-centered teaching, but they failed to predict teacher-centered teaching. Teaching practices and learning strategies of teachers are related. Teachers frequently select constructivist model strategies, using different teaching practices in their work.

Rate, causes and reporting of medication errors in Jordan: nurses' perspectives.

PubMed

Mrayyan, Majd T; Shishani, Kawkab; Al-Faouri, Ibrahim

2007-09-01

The aim of the study was to describe Jordanian nurses' perceptions about various issues related to medication errors. This is the first nursing study about medication errors in Jordan. This was a descriptive study. A convenient sample of 799 nurses from 24 hospitals was obtained. Descriptive and inferential statistics were used for data analysis. Over the course of their nursing career, the average number of recalled committed medication errors per nurse was 2.2. Using incident reports, the rate of medication errors reported to nurse managers was 42.1%. Medication errors occurred mainly when medication labels/packaging were of poor quality or damaged. Nurses failed to report medication errors because they were afraid that they might be subjected to disciplinary actions or even lose their jobs. In the stepwise regression model, gender was the only predictor of medication errors in Jordan. Strategies to reduce or eliminate medication errors are required.

The relationship between formative and summative examinations and PANCE scores; can the past predict the future?

PubMed

Massey, Scott; Stallman, John; Lee, Louise; Klingaman, Kathy; Holmerud, David

2011-01-01

This paper describes how a systematic analysis of students at risk for failing the Physician Assistant National Certifying Examination (PANCE) may be used to identify which students may benefit from intervention prior to taking the PANCE and thus increase the likelihood of successful completion of the PANCE. The intervention developed and implemented uses various formative and summative examinations to predict students' PANCE scores with a high degree of accuracy. Eight end-of-rotation exams (EOREs) based upon discipline-specific diseases and averaging 100 questions each, a 360-question PANCE simulation (SUMM I), the PACKRAT, and a 700-question summative cognitive examination based upon the NCCPA blueprint (SUMM II) were administered to all students enrolled in the program during the clinical year starting in January 2010 and concluding in December 2010. When the PACKRAT, SUMM I, SUMM II, and the surgery, women's health, and pediatrics EOREs were combined in a regression model, an Rvalue of 0.87 and an R2 of 0.75 were obtained. A predicted score was generated for the class of 2009. The predicted PANCE score based upon this model had a final correlation of 0.790 with the actual PANCE score. This pilot study demonstrated that valid predicted scores could be generated from formative and summative examinations to provide valuable feedback and to identify students at risk of failing the PANCE.

Declining prevalence of HIV-1 drug resistance in treatment-failing patients: a clinical cohort study.

PubMed

Di Giambenedetto, Simona; Bracciale, Laura; Colafigli, Manuela; Colatigli, Manuela; Cattani, Paola; Pinnetti, Carmen; Pannetti, Carmen; Bacarelli, Alessandro; Prosperi, Mattia; Fadda, Giovanni; Cauda, Roberto; De Luca, Andrea

2007-01-01

A major barrier to successful viral suppression in HIV type 1 (HIV-1)-infected individuals is the emergence of virus resistant to antiretroviral drugs. We explored the evolution of genotypic drug resistance prevalence in treatment-failing patients from 1999 to 2005 in a clinical cohort. Prevalence of major International AIDS Society-USA HIV-1 drug resistance mutations was measured over calendar years in a population with treatment failure and undergoing resistance testing. Predictors of the presence of resistance mutations were analysed by logistic regression. Significant reductions of the prevalence of resistance to all three drug classes examined were observed. This was accompanied by a reduction in the proportion of treatment-failing patients. Independent predictors of drug resistance were the earlier calendar year, prior use of suboptimal nucleoside analogue therapy, male sex and higher CD4 levels at testing. In a single clinical cohort, we observed a decrease in the prevalence of resistance to all three examined antiretroviral drug classes over time. If this finding is confirmed in multicentre cohorts it may translate into reduced transmission of drug-resistant virus from treated patients.

Analysis and Evaluation of the LANDSAT-4 MSS and TM Sensors and Ground Data Processing Systems: Early Results

NASA Technical Reports Server (NTRS)

Bernstein, R.; Lotspiech, J. B.

1985-01-01

The MSS and TM sensor performances were evaluated by studying both the sensors and the characteristics of the data. Information content analysis, image statistics, band-to-band registration, the presence of failed or failing detectors, and sensor resolution are discussed. The TM data were explored from the point of view of adequacy of the ground processing and improvements that could be made to compensate for sensor problems and deficiencies. Radiometric correction processing, compensation for a failed detector, and geometric correction processing are also considered.

Adjusting for overdispersion in piecewise exponential regression models to estimate excess mortality rate in population-based research.

PubMed

Luque-Fernandez, Miguel Angel; Belot, Aurélien; Quaresma, Manuela; Maringe, Camille; Coleman, Michel P; Rachet, Bernard

2016-10-01

In population-based cancer research, piecewise exponential regression models are used to derive adjusted estimates of excess mortality due to cancer using the Poisson generalized linear modelling framework. However, the assumption that the conditional mean and variance of the rate parameter given the set of covariates x i are equal is strong and may fail to account for overdispersion given the variability of the rate parameter (the variance exceeds the mean). Using an empirical example, we aimed to describe simple methods to test and correct for overdispersion. We used a regression-based score test for overdispersion under the relative survival framework and proposed different approaches to correct for overdispersion including a quasi-likelihood, robust standard errors estimation, negative binomial regression and flexible piecewise modelling. All piecewise exponential regression models showed the presence of significant inherent overdispersion (p-value <0.001). However, the flexible piecewise exponential model showed the smallest overdispersion parameter (3.2 versus 21.3) for non-flexible piecewise exponential models. We showed that there were no major differences between methods. However, using a flexible piecewise regression modelling, with either a quasi-likelihood or robust standard errors, was the best approach as it deals with both, overdispersion due to model misspecification and true or inherent overdispersion.

Obstetrical and neonatal outcomes following unsuccessful external cephalic version: a stratified analysis amongst failures, successes, and controls.

PubMed

Balayla, Jacques; Dahdouh, Elias M; Villeneuve, Sophie; Boucher, Marc; Gauthier, Robert J; Audibert, François; Fuchs, Florent

2015-03-01

Though on average one out of every two external cephalic versions (ECV) fails to rotate the breech fetus, little is known about the outcomes of pregnancies in which ECV is unsuccessful. The objective of the present study is to compare obstetrical and neonatal outcomes following failure of ECV, relative to cases of breech controls without an attempt at ECV. We conducted a retrospective, population-based, cohort study using the CDC's Birth Data files from the US for the year 2006. We stratified the cohort according to fetal presentation and ECV status: success, failure, and no ECV (controls). The effect of failure of ECV on the risk of several neonatal and obstetrical outcomes was estimated using logistic regression analysis, adjusting for relevant confounders. We analyzed a total of 4 273 225 births, out of which 183 323 (4.3%) met inclusion criteria. Relative to breech controls, failed ECV occurred more frequently amongst Caucasian, college-educated, married women bearing a female fetus. Compared to no ECV, failure of ECV was associated with increased odds of PROM (aOR, 1.75; 95% CI, 1.60-1.90), elective cesarean delivery (aOR, 1.53; 95% CI, 1.36-1.72), cesarean delivery in labor (aOR, 1.38; 95% CI, 1.21-1.57), abnormal fetal heart tracing (aOR, 1.78; 95% CI, 1.50-2.11), assisted ventilation at birth (aOR, 1.50; 95% CI, 1.27-1.78), 5-min APGAR scores <7 (aOR, 1.35; 95% CI, 1.20-1.51), and NICU admission (aOR, 1.48; 95% CI, 1.20-1.82). The delayed spontaneous fetal restitution rate was 13%. When stratifying controls with regards to trial of labor status, the increased risk of failed ECV persisted for cesarean delivery, NICU admission, assisted ventilation and abnormal fetal tracing, independently of whether a trial of labor took place. Relative to breech controls without attempt at ECV, failure of ECV to restitute cephalic presentation appears to be associated with an increased risk of adverse perinatal and obstetrical outcomes.

[Regression analysis to select native-like structures from decoys of antigen-antibody docking].

PubMed

Chen, Zhengshan; Chi, Xiangyang; Fan, Pengfei; Zhang, Guanying; Wang, Meirong; Yu, Changming; Chen, Wei

2018-06-25

Given the increasing exploitation of antibodies in different contexts such as molecular diagnostics and therapeutics, it would be beneficial to unravel properties of antigen-antibody interaction with modeling of computational protein-protein docking, especially, in the absence of a cocrystal structure. However, obtaining a native-like antigen-antibody structure remains challenging due in part to failing to reliably discriminate accurate from inaccurate structures among tens of thousands of decoys after computational docking with existing scoring function. We hypothesized that some important physicochemical and energetic features could be used to describe antigen-antibody interfaces and identify native-like antigen-antibody structure. We prepared a dataset, a subset of Protein-Protein Docking Benchmark Version 4.0, comprising 37 nonredundant 3D structures of antigen-antibody complexes, and used it to train and test multivariate logistic regression equation which took several important physicochemical and energetic features of decoys as dependent variables. Our results indicate that the ability to identify native-like structures of our method is superior to ZRANK and ZDOCK score for the subset of antigen-antibody complexes. And then, we use our method in workflow of predicting epitope of anti-Ebola glycoprotein monoclonal antibody-4G7 and identify three accurate residues in its epitope.

Plasma Homocysteine and Asymmetrical Dimethyl-l-Arginine (ADMA) and Whole Blood DNA Methylation in Early and Neovascular Age-Related Macular Degeneration: A Pilot Study.

PubMed

Pinna, Antonio; Zinellu, Angelo; Tendas, Donatella; Blasetti, Francesco; Carru, Ciriaco; Castiglia, Paolo

2016-01-01

To compare the plasma levels of homocysteine and asymmetrical dimethyl-l-arginine (ADMA) and the degree of whole blood DNA methylation in patients with early and neovascular age-related macular degeneration (AMD) and in controls without maculopathy of any sort. This observational case-control pilot study included 39 early AMD patients, 27 neovascular AMD patients and 132 sex- and age-matched controls without maculopathy. Plasma homocysteine and ADMA concentrations and the degree of whole blood DNA methylation were measured. Quantitative variables were compared by Student's t-test or Mann-Whitney test. Logistic regression models were used to investigate the significance of the association between early or wet AMD and some variables. There were no significant differences in mean plasma homocysteine and ADMA concentrations and in the degree of whole blood DNA methylation between patients with early or neovascular AMD and their controls. Similarly, logistic regression analysis disclosed that plasma homocysteine and ADMA levels were not associated with an increased risk for early or neovascular AMD. We failed to demonstrate an association between early or neovascular AMD and increased plasma homocysteine and/or ADMA. Results also suggest that the degree of whole blood DNA methylation is not a marker of AMD.

Evaluating a grading change at UCSD school of medicine: pass/fail grading is associated with decreased performance on preclinical exams but unchanged performance on USMLE step 1 scores.

PubMed

McDuff, Susan G R; McDuff, DeForest; Farace, Jennifer A; Kelly, Carolyn J; Savoia, Maria C; Mandel, Jess

2014-06-30

To assess the impact of a change in preclerkship grading system from Honors/Pass/Fail (H/P/F) to Pass/Fail (P/F) on University of California, San Diego (UCSD) medical students' academic performance. Academic performance of students in the classes of 2011 and 2012 (constant-grading classes) were collected and compared with performance of students in the class of 2013 (grading-change class) because the grading policy at UCSD SOM was changed for the class of 2013, from H/P/F during the first year (MS1) to P/F during the second year (MS2). For all students, data consisted of test scores from required preclinical courses from MS1 and MS2 years, and USMLE Step 1 scores. Linear regression analysis controlled for other factors that could be predictive of student performance (i.e., MCAT scores, undergraduate GPA, age, gender, etc.) in order to isolate the effect of the changed grading policy on academic performance. The change in grading policy in the MS2 year only, without any corresponding changes to the medical curriculum, presents a unique natural experiment with which to cleanly evaluate the effect of P/F grading on performance outcomes. After controlling for other factors, the grading policy change to P/F grading in the MS2 year had a negative impact on second-year grades relative to first-year grades (the constant-grading classes performed 1.65% points lower during their MS2 year compared to the MS1 year versus 3.25% points lower for the grading-change class, p < 0.0001), but had no observable impact on USMLE Step 1 scores. A change in grading from H/P/F grading to P/F grading was associated with decreased performance on preclinical examinations but no decrease in performance on the USMLE Step 1 examination. These results are discussed in the broader context of the multitude of factors that should be considered in assessing the merits of various grading systems, and ultimately the authors recommend the continuation of pass-fail grading at UCSD School of Medicine.

Intellectual and Emotional Development and School Adjustment in Preterm Children at 6 and 7 Years of Age. Continuation of a Follow-Up Study.

ERIC Educational Resources Information Center

Grigoroiu-Serbanescu, Maria

1984-01-01

Continues a previous five-year follow-up of preterm and full-term children by studying the continuity in their intellectual and emotional development. Prematurity was predictive for school adjustment at ages six and seven only when regression was performed on the preterm group, but failed to be predictive when mixed groups of preterm and full-term…

Embedded measures of performance validity using verbal fluency tests in a clinical sample.

PubMed

Sugarman, Michael A; Axelrod, Bradley N

2015-01-01

The objective of this study was to determine to what extent verbal fluency measures can be used as performance validity indicators during neuropsychological evaluation. Participants were clinically referred for neuropsychological evaluation in an urban-based Veteran's Affairs hospital. Participants were placed into 2 groups based on their objectively evaluated effort on performance validity tests (PVTs). Individuals who exhibited credible performance (n = 431) failed 0 PVTs, and those with poor effort (n = 192) failed 2 or more PVTs. All participants completed the Controlled Oral Word Association Test (COWAT) and Animals verbal fluency measures. We evaluated how well verbal fluency scores could discriminate between the 2 groups. Raw scores and T scores for Animals discriminated between the credible performance and poor-effort groups with 90% specificity and greater than 40% sensitivity. COWAT scores had lower sensitivity for detecting poor effort. A combination of FAS and Animals scores into logistic regression models yielded acceptable group classification, with 90% specificity and greater than 44% sensitivity. Verbal fluency measures can yield adequate detection of poor effort during neuropsychological evaluation. We provide suggested cut points and logistic regression models for predicting the probability of poor effort in our clinical setting and offer suggested cutoff scores to optimize sensitivity and specificity.

Perceived resource support for chronic illnesses among diabetics in north-western China.

PubMed

Zhong, Huiqin; Shao, Ya; Fan, Ling; Zhong, Tangshen; Ren, Lu; Wang, Yan

2016-06-01

A high level of social support can improve long-term diabetes self-management. Support from a single source has been evaluated. This study aims to analyze support from multiple and multilevel sources for diabetic patients by using the Chronic Illness Resources Survey (CIRS). Factors influencing the utilization of the CIRS were also evaluated. A total of 297 patients with diabetes were investigated using the CIRS and Perceived Diabetes Self-management Scale in Shihezi City, China. Descriptive statistics were used to explain demographic variables and scores of the scales. Factors affecting the utilization of chronic illness resources were determined through univariate analysis and then examined by multivariate logistic regression analysis. Of the 297 diabetic patients surveyed, 67% failed to reach the standard (more than 3 points) of utilizing chronic illness resources. Moreover, utilization of chronic illness resources was positively moderately correlated with self-management of diabetes (r = 0.75, P < 0.05). According to the multivariate logistic regression analysis, age (OR, 3.42; 95%CI, 1.19-9.84) and monthly income (OR, 5.27; 95%CI, 1.86-14.90) were significantly positively associated with the CIRS score. Individuals with high school (OR, 2.61; 95%CI, 1.13-6.05) and college (OR, 3.02; 95%CI, 1.13-8.04) degrees obtained higher scores in the survey than those with elementary school education. Results indicated that utilization of resources and support for chronic illness self-management, particularly personal adjustment and organization, were not ideal among diabetics in the communities of north-western China. Improved utilization of chronic illness resources was conducive for proper diabetes self-management. Furthermore, the level of utilization of chronic illness resources increased with age, literacy level, and monthly income.

Do biomass fuel use and consumption of unsafe water mediate educational inequalities in stillbirth risk? An analysis of the 2007 Ghana Maternal Health Survey

PubMed Central

Näyhä, Simo; Jaakkola, Jouni J K

2017-01-01

Background Numerous studies have explored the association between educational inequalities and stillbirth but most have failed to elaborate how low educational attainment leads to an increased risk of stillbirth. We hypothesised that use of biomass fuels and consumption of unsafe water related to low educational attainment could explain the stillbirth burden in Ghana attributable to socioeconomic disadvantage. Methods Data from the 2007 Ghana Maternal Health Survey, a nationally representative population-based survey were analysed for this study. Of the10 370 women aged 15–49 years interviewed via structured questionnaires for the survey, 7183 primiparous and multiparous women qualified for inclusion in the present study. Results In a logistic regression analysis that adjusted for age, area of residence, marital status and ethnicity of women, lower maternal primary education was associated with a 62% (OR=1.62; 95% CI 1.04 to 2.52) increased lifetime risk of stillbirth. Biomass fuel use and consumption of unsafe water mediated 18% and 8% of the observed effects, respectively. Jointly these two exposures explained 24% of the observed effects. The generalised additive modelling revealed a very flat inverted spoon-shaped smoothed curve which peaked at low levels of schooling (2–3 years) and confirms the findings from the logistic regression analysis. Conclusions Our results show that biomass fuel use and unsafe water consumption could be important pathways through which low maternal educational attainment leads to stillbirths in Ghana and similar developing countries. Addressing educational inequalities in developing countries is thus essential for ensuring household choices that curtail environmental exposures and help improve pregnancy outcomes. PMID:28174221

Disambiguating brain functional connectivity.

PubMed

Duff, Eugene P; Makin, Tamar; Cottaar, Michiel; Smith, Stephen M; Woolrich, Mark W

2018-06-01

Functional connectivity (FC) analyses of correlations of neural activity are used extensively in neuroimaging and electrophysiology to gain insights into neural interactions. However, analyses assessing changes in correlation fail to distinguish effects produced by sources as different as changes in neural signal amplitudes or noise levels. This ambiguity substantially diminishes the value of FC for inferring system properties and clinical states. Network modelling approaches may avoid ambiguities, but require specific assumptions. We present an enhancement to FC analysis with improved specificity of inferences, minimal assumptions and no reduction in flexibility. The Additive Signal Change (ASC) approach characterizes FC changes into certain prevalent classes of signal change that involve the input of additional signal to existing activity. With FMRI data, the approach reveals a rich diversity of signal changes underlying measured changes in FC, suggesting that it could clarify our current understanding of FC changes in many contexts. The ASC method can also be used to disambiguate other measures of dependency, such as regression and coherence, providing a flexible tool for the analysis of neural data. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Failure Analysis of Sapphire Refractive Secondary Concentrators

NASA Technical Reports Server (NTRS)

Salem, Jonathan A.; Quinn, George D.

2009-01-01

Failure analysis was performed on two sapphire, refractive secondary concentrators (RSC) that failed during elevated temperature testing. Both concentrators failed from machining/handling damage on the lens face. The first concentrator, which failed during testing to 1300 C, exhibited a large r-plane twin extending from the lens through much of the cone. The second concentrator, which was an attempt to reduce temperature gradients and failed during testing to 649 C, exhibited a few small twins on the lens face. The twins were not located at the origin, but represent another mode of failure that needs to be considered in the design of sapphire components. In order to estimate the fracture stress from fractographic evidence, branching constants were measured on sapphire strength specimens. The fractographic analysis indicated radial tensile stresses of 44 to 65 MPa on the lens faces near the origins. Finite element analysis indicated similar stresses for the first RSC, but lower stresses for the second RSC. Better machining and handling might have prevented the fractures, however, temperature gradients and resultant thermal stresses need to be reduced to prevent twinning.

Systems and methods for circuit lifetime evaluation

NASA Technical Reports Server (NTRS)

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

2013-01-01

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

More than 100 Colleges Fail Education Department's Test of Financial Strength

ERIC Educational Resources Information Center

Blumenstyk, Goldie

2009-01-01

A newly compiled analysis by the U.S. Department of Education and obtained by "The Chronicle" shows that 114 private nonprofit degree-granting colleges were in such fragile financial condition at the end of their last fiscal year that they failed the department's financial-responsibility test. Colleges that fail the test are subject to extra…

Are learning strategies linked to academic performance among adolescents in two States in India? A tobit regression analysis.

PubMed

Areepattamannil, Shaljan

2014-01-01

The results of the fourth cycle of the Program for International Student Assessment (PISA) revealed that an unacceptably large number of adolescent students in two states in India-Himachal Pradesh and Tamil Nadu-have failed to acquire basic skills in reading, mathematics, and science (Walker, 2011). Drawing on data from the PISA 2009 database and employing multivariate left-censored to bit regression as a data analytic strategy, the present study, therefore, examined whether or not the learning strategies-memorization, elaboration, and control strategies-of adolescent students in Himachal Pradesh (N = 1,616; Mean age = 15.81 years) and Tamil Nadu (N = 3,210; Mean age = 15.64 years) were linked to their performance on the PISA 2009 reading, mathematics, and science assessments. Tobit regression analyses, after accounting for student demographic characteristics, revealed that the self-reported use of control strategies was significantly positively associated with reading, mathematical, and scientific literacy of adolescents in Himachal Pradesh and Tamil Nadu. While the self-reported use of elaboration strategies was not significantly associated with reading literacy among adolescents in Himachal Pradesh and Tamil Nadu, it was significantly positively associated with mathematical literacy among adolescents in Himachal Pradesh and Tamil Nadu. Moreover, the self-reported use of elaboration strategies was significantly and positively linked to scientific literacy among adolescents in Himachal Pradesh alone. The self-reported use of memorization strategies was significantly negatively associated with reading, mathematical, and scientific literacy in Tamil Nadu, while it was significantly negatively associated with mathematical and scientific literacy alone in Himachal Pradesh. Implications of these findings are discussed.

Evaluation of the efficiency of continuous wavelet transform as processing and preprocessing algorithm for resolution of overlapped signals in univariate and multivariate regression analyses; an application to ternary and quaternary mixtures.

PubMed

Hegazy, Maha A; Lotfy, Hayam M; Mowaka, Shereen; Mohamed, Ekram Hany

2016-07-05

Wavelets have been adapted for a vast number of signal-processing applications due to the amount of information that can be extracted from a signal. In this work, a comparative study on the efficiency of continuous wavelet transform (CWT) as a signal processing tool in univariate regression and a pre-processing tool in multivariate analysis using partial least square (CWT-PLS) was conducted. These were applied to complex spectral signals of ternary and quaternary mixtures. CWT-PLS method succeeded in the simultaneous determination of a quaternary mixture of drotaverine (DRO), caffeine (CAF), paracetamol (PAR) and p-aminophenol (PAP, the major impurity of paracetamol). While, the univariate CWT failed to simultaneously determine the quaternary mixture components and was able to determine only PAR and PAP, the ternary mixtures of DRO, CAF, and PAR and CAF, PAR, and PAP. During the calculations of CWT, different wavelet families were tested. The univariate CWT method was validated according to the ICH guidelines. While for the development of the CWT-PLS model a calibration set was prepared by means of an orthogonal experimental design and their absorption spectra were recorded and processed by CWT. The CWT-PLS model was constructed by regression between the wavelet coefficients and concentration matrices and validation was performed by both cross validation and external validation sets. Both methods were successfully applied for determination of the studied drugs in pharmaceutical formulations. Copyright © 2016 Elsevier B.V. All rights reserved.

Failure factors in non-life insurance companies in United Kingdom

NASA Astrophysics Data System (ADS)

Samsudin, Humaida Banu

2013-04-01

Failure in insurance company is a condition of financial distress where a company has difficulty paying off its financial obligations to its creditors. This study continues the research from the study in identifying the determinants for run-off non-life insurance companies in United Kingdom. The analysis continues to identify other variables that could lead companies to financial distress that is macroeconomic factors (GDP rates, inflation rates and interest rates); total companies failed a year before and average size for failed companies'. The result from the analysis indicates that inflation rates, interest rates, total companies failed a year before and average sizes for failed companies are the best predictors. An early detection of failure can prevent companies from bankruptcy and allow management to take action to reduce the failure costs.

Regression Analysis of a Disease Onset Distribution Using Diagnosis Data

PubMed Central

Young, Jessica G.; Jewell, Nicholas P.; Samuels, Steven J.

2008-01-01

Summary We consider methods for estimating the effect of a covariate on a disease onset distribution when the observed data structure consists of right-censored data on diagnosis times and current status data on onset times amongst individuals who have not yet been diagnosed. Dunson and Baird (2001, Biometrics 57, 306–403) approached this problem using maximum likelihood, under the assumption that the ratio of the diagnosis and onset distributions is monotonic nondecreasing. As an alternative, we propose a two-step estimator, an extension of the approach of van der Laan, Jewell, and Petersen (1997, Biometrika 84, 539–554) in the single sample setting, which is computationally much simpler and requires no assumptions on this ratio. A simulation study is performed comparing estimates obtained from these two approaches, as well as that from a standard current status analysis that ignores diagnosis data. Results indicate that the Dunson and Baird estimator outperforms the two-step estimator when the monotonicity assumption holds, but the reverse is true when the assumption fails. The simple current status estimator loses only a small amount of precision in comparison to the two-step procedure but requires monitoring time information for all individuals. In the data that motivated this work, a study of uterine fibroids and chemical exposure to dioxin, the monotonicity assumption is seen to fail. Here, the two-step and current status estimators both show no significant association between the level of dioxin exposure and the hazard for onset of uterine fibroids; the two-step estimator of the relative hazard associated with increasing levels of exposure has the least estimated variance amongst the three estimators considered. PMID:17680832

Risk factors for poor multidrug-resistant tuberculosis treatment outcomes in Kyiv Oblast, Ukraine.

PubMed

Aibana, Omowunmi; Bachmaha, Mariya; Krasiuk, Viatcheslav; Rybak, Natasha; Flanigan, Timothy P; Petrenko, Vasyl; Murray, Megan B

2017-02-07

Ukraine is among ten countries with the highest burden of multidrug- resistant TB (MDR-TB) worldwide. Treatment success rates for MDR-TB in Ukraine remain below global success rates as reported by the World Health Organization. Few studies have evaluated predictors of poor MDR-TB outcomes in Ukraine. We conducted a retrospective analysis of patients initiated on MDR-TB treatment in the Kyiv Oblast of Ukraine between January 01, 2012 and March 31st, 2015. We defined good treatment outcomes as cure or completion and categorized poor outcomes among those who died, failed treatment or defaulted. We used logistic regression analyses to identify baseline patient characteristics associated with poor MDR-TB treatment outcomes. Among 360 patients, 65 (18.1%) achieved treatment cure or completion while 131 (36.4%) died, 115 (31.9%) defaulted, and 37 (10.3%) failed treatment. In the multivariate analysis, the strongest baseline predictors of poor outcomes were HIV infection without anti-retroviral therapy (ART) initiation (aOR 10.07; 95% CI 1.20-84.45; p 0.03) and presence of extensively-drug resistant TB (aOR 9.19; 95% CI 1.17-72.06; p 0.03). HIV-positive patients initiated on ART were not at increased risk of poor outcomes (aOR 1.43; 95% CI 0.58-3.54; p 0.44). There was no statistically significant difference in risk of poor outcomes among patients who received baseline molecular testing with Gene Xpert compared to those who were not tested (aOR 1.31; 95% CI 0.63-2.73). Rigorous compliance with national guidelines recommending prompt initiation of ART among HIV/TB co-infected patients and use of drug susceptibility testing results to construct treatment regimens can have a major impact on improving MDR-TB treatment outcomes in Ukraine.

Analysis of failed discharge after ambulatory surgery: unanticipated admission.

PubMed

Van Caelenberg, Els; De Regge, Melissa; Eeckloo, Kristof; Coppens, Marc

2018-05-30

Advantages of ambulatory surgery are lost when patients need an unplanned admission. This retrospective cohort study investigated reasons for failed discharge and unanticipated admission of adult patients after day surgery. Ambulatory patients (n = 145) requiring unanticipated admission were compared to patients (n = 4980) not requiring admission and timely discharged from a total of 5156 ambulatory surgical procedures. Demographic data, organisational data, reason for admission, type of anesthesia, surgical discipline, length of procedure, ASA classification, surgical completion time and severity of illness score were collected from both groups. Reason for admission was classified according to four subtypes. Logistic regression analysis was used. Incidence of unanticipated admission following day care surgery was 2.89%. The reasons for admission were mainly organisational issues (45.52%), time of completion surgery in the afternoon between 12 pm and 3 pm (OR 1.73; 95% CI 1.05-2.86) and surgery that ends after 3 pm (OR 6.52; 95% CI 4.11-10.34). Surgical factors associated with unanticipated admission (38.62%) were length of surgery of one to three hours (OR 2.05; 95% CI 1.27-3.29), length of surgery more than three hours (OR 8.31; 95% CI 3.56-19.40). Additionally, anaesthetic (10.34%) and medical (5.52%) reasons were found, e.g. ASA class II (OR 1.61; 95% CI 1.06-2.44), ASA class III (OR 2.19; 95% CI 1.10-4.34); moderate severity of illness score (OR 1.72; 95% CI 1.03-2.88) and major of severity of illness score (OR 7.85; 95% CI 2.31-26.62). Unanticipated admissions following day surgery occur mainly due to social/organisational and surgical reasons. However, medical and anaesthetic reasons also explain 15.86% of the unanticipated admissions.

Sustained virological response and baseline predictors in HIV-HCV coinfected patients retreated with pegylated interferon and ribavirin after failing a previous interferon-based therapy: systematic review and meta-analysis.

PubMed

Basso, Monica; Parisi, Saverio Giuseppe; Mengoli, Carlo; Gentilini, Valeria; Menegotto, Nicola; Monticelli, Jacopo; Nicolè, Stefano; Cruciani, Mario; Palù, Giorgio

2013-01-01

Published data on retreatment with pegylated interferon and ribavirin of previously failing HIV-HCV coinfected patients are sparse and limited to observational study. We aimed to evaluate efficacy and pretreatment predictors. Systematic review and meta-analysis of observational studies. The overall and genotype-related success rate was investigated. A direct comparison was performed between genotypes 1/4 and 2/3 by evaluating the sustained virological response (SVR) rate ratio (RR). The effect of study level variables on the effect size was investigated by meta-regression. Variables that were analyzed included age, gender, advanced hepatic fibrosis, pretreatment of HCV RNA and CD4, and successful antiretroviral treatment (ART). The available evidence was from 5 open-label, cohort studies (275 patients). The overall SVR rate was 0.280 (95% CI,0.171-0.425). The SVR rate in genotype 1/4 infections was 0.174 (95% CI, 0.129-0.230), and in genotype 2/3 infections it was 0.474 (95% CI, 0.286-0.670). The pooled RR comparing the SVR of genotype 1/4 to 2/3 was 0.369 (95% CI, 0.239-0.568), with a decreased probability of response for genotype 1/4 (P < .001). HIV RNA suppression had a significant effect on SVR (P = .005). The other covariates had no effect on the overall SVR rate. The overall SVR rate was 28%, consistent with the rate reported in the retreatment of mono-infected patients with the same schedule. A substantial relative reduction in the SVR rate of about one-third, when treating genotypes 1/4, was found, with a low SVR rate of 17%. Successful HIV suppression by ART predicted a higher rate of treatment success.

Examining the association between posttraumatic stress disorder and attention-deficit/hyperactivity disorder: a systematic review and meta-analysis.

PubMed

Spencer, Andrea E; Faraone, Stephen V; Bogucki, Olivia E; Pope, Amanda L; Uchida, Mai; Milad, Mohammed R; Spencer, Thomas J; Woodworth, K Yvonne; Biederman, Joseph

2016-01-01

To conduct a systematic review and meta-analysis examining the relationship between attention-deficit/hyperactivity disorder (ADHD) and posttraumatic stress disorder (PTSD). We reviewed literature through PubMed and PsycINFO without a specified date range, utilizing the search (posttraumatic stress disorder OR PTSD) AND (ADHD OR attention deficit hyperactivity disorder OR ADD OR attention deficit disorder OR hyperkinetic syndrome OR minimal brain dysfunction). References from relevant articles were reviewed. We identified 402 articles; 28 met criteria. We included original human research in English that operationalized diagnoses of ADHD and PTSD, evaluated the relationship between the disorders, and included controls. We excluded articles that failed to differentiate ADHD or PTSD from nonspecific or subsyndromal deficits or failed to compare their relationship. We extracted sample size, age, diagnostic methods, design, referral status, control type, and number of subjects with and without ADHD and PTSD alone and combined. We computed meta-analyses for 22 studies examining ADHD in PTSD and PTSD in ADHD using a random effects model and meta-analytic regression. We assessed for heterogeneity and publication bias and adjusted for intrastudy clustering. The relative risk (RR) for PTSD in ADHD was 2.9 (P < .0005); in samples using healthy controls, the RR was 3.7 (P = .001); and in samples using traumatized controls, the RR was 1.6 (P = .003). The RR for ADHD in PTSD was 1.7 (P < .0005); in samples using traumatized controls, the RR was 2.1 (P < .0005). The association was not significant in samples using psychiatric controls. Results indicate a bidirectional association between ADHD and PTSD, suggesting clinical implications and highlighting the need for neurobiological research that examines the mechanisms underlying this connection. © Copyright 2015 Physicians Postgraduate Press, Inc.

The Influence of Cement Morphology Parameters on the Strength of the Cement-Bone Interface in Tibial Tray Fixation.

PubMed

Nagel, Katrin; Bishop, Nicholas E; Schlegel, Ulf J; Püschel, Klaus; Morlock, Michael M

2017-02-01

The strength of the cement-bone interface in tibial component fixation depends on the morphology of the cement mantle. The purpose of this study was to identify thresholds of cement morphology parameters to maximize fixation strength using a minimum amount of cement. Twenty-three cadaveric tibiae were analyzed that had been implanted with tibial trays in previous studies and for which the pull-out strength of the tray had been measured. Specimens were separated into a group failing at the cement-bone interface (INTERFACE) and one failing in the bulk bone (BULK). Maximum pull-out strength corresponds to the ultimate strength of the bulk bone if the cement-bone interface is sufficiently strong. 3D models of the cement mantle in situ were reconstructed from computed tomography scans. The influences of bone mineral density and 6 cement morphology parameters (reflecting cement penetration, bone-cement interface, cement volume) on pull-out strength of the BULK group were determined using multiple regression analysis. The threshold of each parameter for classification of the specimens into either group was determined using receiver operating characteristic analysis. Cement penetration exceeding a mean of 1.1 mm or with a maximum of 5.6 mm exclusively categorized all BULK bone failure specimens. Failure strength of BULK failure specimens increased with bone mineral density (R 2  = 0.67, P < .001) but was independent of the cement morphology parameters. To maximize fixation strength, a mean cement penetration depth of at least 1.1 mm should be achieved during tibial tray cementing. Copyright © 2016 Elsevier Inc. All rights reserved.

The Impact of Financial Conflict of Interest on Surgical Research: An Observational Study of Published Manuscripts.

PubMed

Cherla, Deepa V; Viso, Cristina P; Olavarria, Oscar A; Bernardi, Karla; Holihan, Julie L; Mueck, Krislynn M; Flores-Gonzalez, Juan; Liang, Mike K; Adams, Sasha D

2018-02-09

Substantial discrepancies exist between industry-reported and self-reported conflicts of interest (COI). Although authors with relevant, self-reported financial COI are more likely to write studies favorable to industry sponsors, it is unknown whether undisclosed COI have the same effect. We hypothesized that surgeons who fail to disclose COI are more likely to publish findings that are favorable to industry than surgeons with no COI. PubMed was searched for articles in multiple surgical specialties. Financial COI reported by surgeons and industry were compared. COI were considered to be relevant if they were associated with the product(s) mentioned by an article. Primary outcome was favorability, which was defined as an impression favorable to the product(s) discussed by an article and was determined by 3 independent, blinded clinicians for each article. Primary analysis compared incomplete self-disclosure to no COI. Ordered logistic multivariable regression modeling was used to assess factors associated with favorability. Overall, 337 articles were reviewed. There was a high rate of discordance in the reporting of COI (70.3%). When surgeons failed to disclose COI, their conclusions were significantly more likely to favor industry than surgeons without COI (RR 1.2, 95% CI 1.1-1.4, p < 0.001). On multivariable analysis, any COI (regardless of relevance, disclosure, or monetary amount) were significantly associated with favorability. Any financial COI (disclosed or undisclosed, relevant or not relevant) significantly influence whether studies report findings favorable to industry. More attention must be paid to improving research design, maximizing transparency in medical research, and insisting that surgeons disclose all COI, regardless of perceived relevance.

Flight Deck Refuelling Hose Failure HMCS Preserver

DTIC Science & Technology

2000-01-01

hose and these were used as a basis for the investigation. Chemical analysis indicated that the inner tube and outer cover of the hose were as...Principal Results Chemical analysis indicated that the inner tube (poly(butadiene-acrylonitrile) rubber) and outer cover of the hose (poly( chloroprene... Analysis Py-GC/MS Instrumentation and Experimental Conditions Failed Titan Hose New Titan Hose German Hose Proof Tests Failed Titan Hose New

Time-resolved versus time-integrated portal dosimetry: the role of an object’s position with respect to the isocenter in volumetric modulated arc therapy

NASA Astrophysics Data System (ADS)

Schyns, Lotte E. J. R.; Persoon, Lucas C. G. G.; Podesta, Mark; van Elmpt, Wouter J. C.; Verhaegen, Frank

2016-05-01

The aim of this work is to compare time-resolved (TR) and time-integrated (TI) portal dosimetry, focussing on the role of an object’s position with respect to the isocenter in volumetric modulated arc therapy (VMAT). Portal dose images (PDIs) are simulated and measured for different cases: a sphere (1), a bovine bone (2) and a patient geometry (3). For the simulated case (1) and the experimental case (2), several transformations are applied at different off-axis positions. In the patient case (3), three simple plans with different isocenters are created and pleural effusion is simulated in the patient. The PDIs before and after the sphere transformations, as well as the PDIs with and without simulated pleural effusion, are compared using a TI and TR gamma analysis. In addition, the performance of the TI and TR gamma analyses for the detection of real geometric changes in patients treated with clinical plans is investigated and a correlation analysis is performed between gamma fail rates and differences in dose volume histogram (DVH) metrics. The TI gamma analysis can show large differences in gamma fail rates for the same transformation at different off-axis positions (or for different plan isocenters). The TR gamma analysis, however, shows consistent gamma fail rates. For the detection of real geometric changes in patients treated with clinical plans, the TR gamma analysis has a higher sensitivity than the TI gamma analysis. However, the specificity for the TR gamma analysis is lower than for the TI gamma analysis. Both the TI and TR gamma fail rates show no correlation with changes in DVH metrics. This work shows that TR portal dosimetry is fundamentally superior to TI portal dosimetry, because it removes the strong dependence of the gamma fail rate on the off-axis position/plan isocenter. However, for 2D TR portal dosimetry, it is still difficult to interpret gamma fail rates in terms of changes in DVH metrics for patients treated with VMAT.

Steep Delay Discounting and Addictive Behavior: A Meta-Analysis of Continuous Associations

PubMed Central

Amlung, Michael; Vedelago, Lana; Acker, John; Balodis, Iris; MacKillop, James

2016-01-01

Aims To synthesize continuous associations between delayed reward discounting (DRD) and both addiction severity and quantity-frequency (QF); to examine moderators of these relationships; and to investigate publication bias. Methods Meta-analysis of published studies examining continuous associations between DRD and addictive behaviors. Published, peer-reviewed studies on addictive behaviors (alcohol, tobacco, cannabis, stimulants, opiates, and gambling) were identified via PubMed, MEDLINE, and PsycInfo. Studies were restricted to DRD measures of monetary gains. Random effects meta-analysis was conducted using Pearson’s r as the effect size. Publication bias was evaluated using fail-safe N, Begg-Mazumdar and Egger’s tests, meta-regression of publication year and effect size, and imputation of missing studies. Results The primary meta-analysis revealed a small magnitude effect size that was highly significant (r = 0.14, p < 10−14). Significantly larger effect sizes were observed for studies examining severity compared with QF (p = 0.01), but not between the type of addictive behavior (p = 0.30) or DRD assessment (p = 0.90). Indices of publication bias suggested a modest impact of unpublished findings. Conclusions Delayed reward discounting is robustly associated with continuous measures of addiction severity and quantity-frequency. This relation is generally robust across type of addictive behavior and delayed reward discounting assessment modality. PMID:27450931

Failure Analysis and Magnetic Evaluation of Tertiary Superheater Tube Used in Gas-Fired Boiler

NASA Astrophysics Data System (ADS)

Mohapatra, J. N.; Patil, Sujay; Sah, Rameshwar; Krishna, P. C.; Eswarappa, B.

2018-02-01

Failure analysis was carried out on a prematurely failed tertiary superheater tube used in gas-fired boiler. The analysis includes a comparative study of visual examination, chemical composition, hardness and microstructure at failed region, adjacent and far to failure as well as on fresh tube. The chemistry was found matching to the standard specification, whereas the hardness was low in failed tube compared to the fish mouth opening region and the fresh tube. Microscopic examination of failed sample revealed the presence of spheroidal carbides of Cr and Mo predominantly along the grain boundaries. The primary cause of failure is found to be localized heating. Magnetic hysteresis loop (MHL) measurements were carried out to correlate the magnetic parameters with microstructure and mechanical properties to establish a possible non-destructive evaluation (NDE) for health monitoring of the tubes. The coercivity of the MHL showed a very good correlation with microstructure and mechanical properties deterioration enabling a possible NDE technique for the health monitoring of the tubes.

Effective palliation for advanced esophageal cancer using intralumenal irradiation.

PubMed

Makarewicz, R; Czechowicz, W; Kabacińska, R

1996-01-01

Palliative treatment by intracavitary irradiation alone has been used in 15 patients with advanced carcinoma of the esophagus. Most of them had already failed other palliative modalities including external irradiation, chemoradiotherapy, laserotherapy and dilatation. Intracavitary irradiation was carried out with a microSelectron HDR afterloading device and usually 22.5 Gy was given in three fractions repeated weekly. Up to three month after treatment, complete endoscopic regression was seen in 1 patient, partial endoscopic regression in 8 patients, no response in one and progressive disease in 5 patients. The median survival time is 6.2 months. There were not severe complications. We conclude that high dose rate intracavitary irradiation is a useful palliative modality in patients with advanced or recurrent esophageal cancer.

Missing data treatments matter: an analysis of multiple imputation for anterior cervical discectomy and fusion procedures.

PubMed

Ondeck, Nathaniel T; Fu, Michael C; Skrip, Laura A; McLynn, Ryan P; Cui, Jonathan J; Basques, Bryce A; Albert, Todd J; Grauer, Jonathan N

2018-04-09

The presence of missing data is a limitation of large datasets, including the National Surgical Quality Improvement Program (NSQIP). In addressing this issue, most studies use complete case analysis, which excludes cases with missing data, thus potentially introducing selection bias. Multiple imputation, a statistically rigorous approach that approximates missing data and preserves sample size, may be an improvement over complete case analysis. The present study aims to evaluate the impact of using multiple imputation in comparison with complete case analysis for assessing the associations between preoperative laboratory values and adverse outcomes following anterior cervical discectomy and fusion (ACDF) procedures. This is a retrospective review of prospectively collected data. Patients undergoing one-level ACDF were identified in NSQIP 2012-2015. Perioperative adverse outcome variables assessed included the occurrence of any adverse event, severe adverse events, and hospital readmission. Missing preoperative albumin and hematocrit values were handled using complete case analysis and multiple imputation. These preoperative laboratory levels were then tested for associations with 30-day postoperative outcomes using logistic regression. A total of 11,999 patients were included. Of this cohort, 63.5% of patients had missing preoperative albumin and 9.9% had missing preoperative hematocrit. When using complete case analysis, only 4,311 patients were studied. The removed patients were significantly younger, healthier, of a common body mass index, and male. Logistic regression analysis failed to identify either preoperative hypoalbuminemia or preoperative anemia as significantly associated with adverse outcomes. When employing multiple imputation, all 11,999 patients were included. Preoperative hypoalbuminemia was significantly associated with the occurrence of any adverse event and severe adverse events. Preoperative anemia was significantly associated with the occurrence of any adverse event, severe adverse events, and hospital readmission. Multiple imputation is a rigorous statistical procedure that is being increasingly used to address missing values in large datasets. Using this technique for ACDF avoided the loss of cases that may have affected the representativeness and power of the study and led to different results than complete case analysis. Multiple imputation should be considered for future spine studies. Copyright © 2018 Elsevier Inc. All rights reserved.

Guiding the Development and Use of Cost-Effectiveness Analysis in Education

ERIC Educational Resources Information Center

Levin, Henry M.; Belfield, Clive

2015-01-01

Cost-effectiveness analysis is rarely used in education. When it is used, it often fails to meet methodological standards, especially with regard to cost measurement. Although there are occasional criticisms of these failings, we believe that it is useful to provide a listing of the more common concerns and how they might be addressed. Based upon…

Supply Rate and Equilibrium Inventory of Air Force Enlisted Personnel: A Simultaneous Model of the Accession and Retention Markets Incorporating Force Level Constraints. Final Report for Period July 1969-June 1976.

ERIC Educational Resources Information Center

DeVany, Arthur S.; And Others

This research was designed to develop and test a model of the Air Force manpower market. The study indicates that previous manpower supply studies failed to account for simultaneous determination of enlistments and retentions and misinterpreted regressions as supply equations. They are, instead, reduced form equations resulting from joint…

Imitating actions on objects in early-onset and regressive autism: Effects and implications of task characteristics on performance

PubMed Central

Rogers, Sally J.; Young, Gregory S.; Cook, Ian; Giolzetti, Angelo; Ozonoff, Sally

2010-01-01

This study was designed to examine the nature of object imitation performance in early autism. We hypothesized that imitation would be relatively preserved when behaviors on objects resulted in salient instrumental effects. We designed tasks in which, in one condition, the motor action resulted in a salient, meaningful effect on an object, whereas in the other condition, the same action resulted in a less salient effect because of differing object characteristics. The motor aspects of the tasks did not vary across conditions. Four participant groups of 2- to 5-year-olds were examined: 17 children with early-onset autism, 24 children with regressive onset autism, 22 children with developmental delays, and 22 children with typical development. Groups were matched on nonverbal skills, and differences in verbal development were examined as a moderator of imitative ability. Results revealed an interaction of group by condition, with the combined autism group failing more tasks than the combined comparison groups, and failing more tasks in the less salient condition than in the more salient condition, as hypothesized. Analyses of autism subgroups revealed these effects were primarily because of the regression onset group. Accuracy of motor performance was examined by analyzing errors. Among children passing imitative acts, there were no group differences and no condition effects in the number, type, or pattern of performance errors. Among children passing the tasks, the group with autism did not demonstrate more emulation errors (imitating the goal but not the means) than other groups. There was no evidence that either motor or attentional aspects of the tasks contributed to the poorer imitative performance of the children with autism. PMID:20102648

Setting appropriate pass or fail cut-off criteria for tests to reflect real life listening difficulties in children with suspected auditory processing disorder.

PubMed

Ahmmed, Ansar U; Ahmmed, Afsara A

2016-05-01

This paper explores the pass or fail cut-off criteria, the number of test fails, and the nature of tests that are most appropriate in predicting listening difficulties (LiD) in children with suspected APD (SusAPD). One hundred and nine English-speaking children (67 males, 42 females) aged between 6 and 11 years with SusAPD were assessed. The Children's Auditory Performance Scale (CHAPS) scores 2 SD below the mean were taken as markers of LiD in different listening conditions. Binary logistic regression analyses were carried out to evaluate the cut-off criterion (2 SD or 1.5 SD or 1 SD below the mean) of failing at least two tests, from the SCAN-C and IMAP test batteries, which significantly predicted LiD. Analyses were also carried out to assess if the group of auditory processing (AP) or cognitive or combination of AP plus cognitive tests were significant in predicting LiD. Receiver Operative Characteristic (ROC) curves were also explored to evaluate how the sensitivity and specificity in confirming LiD varied with the number of test fails. Filtered Words, Competing Words, Competing Sentences, VCV in ICRA noise, Digit Span, Sight Word Reading and the Cued Auditory Attention tests correlated with one or more of the CHAPS domains. Failing at least two of these tests 1.5 SD below the mean significantly predicted (p<.05) CHAPS Ideal scores 2 SD below the mean, and failing at least two of the tests 1 SD below the mean significantly predicted (p<.05) CHAPS Memory and CHAPS Attention scores 2 SD below the mean. The combination of AP plus cognitive tests had significantly higher ability to predict CHAPS Ideal, Memory and Attention scores, compared to the group of AP or cognitive tests separately. ROC curves showed that failing at least two of the tests was associated with the best sensitivity and specificity in predicting LiD. Of the different CHAPS domains only the CHAPS Ideal, Memory and Attention correlated with the APD tests. Failing at least two APD tests from a combination of AP and cognitive tests 1 SD and 1.5 SD below the mean, but not 2 SD, is more appropriate in confirming LiD. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

An analysis of surgical and anaesthetic factors affecting skin graft viability in patients admitted to a Burns Intensive Care Unit.

PubMed

Isitt, Catherine E; McCloskey, Kayleigh A; Caballo, Alvaro; Sharma, Pranev; Williams, Andrew; Leon-Villapalos, Jorge; Vizcaychipi, Marcela P

2016-01-01

Skin graft failure is a recognised complication in the treatment of major burns. Little research to date has analysed the impact of the complex physiological management of burns patients on the success of skin grafting. We analysed surgical and anaesthetic variables to identify factors contributing to graft failure. Inclusion criteria were admission to our Burns Intensive Care Unit (BICU) between January 2009 and October 2013 with a major burn. After exclusion for death before hospital discharge or prior skin graft at a different hospital, 35 patients remained and were divided into those with successful autografts (n=16) and those with a failed autograft (n=19). For the purposes of this study, we defined poor autograft viability as requiring at least one additional skin graft to the same site. Logistic regression of variables was performed using SPSS (Version 22.0 IBMTM). Age, Sex, %Total Burn Surface Area or Belgian Outcome Burns Injury score did not significantly differ between groups. No differences were found in any surgical factor at logistic regression (graft site, harvest site, infection etc.). When all operations were analysed, the use of colloids was found to be significantly associated with graft failure (p=0.035, CI 95%) and this remained significant when only split thickness skin grafts (STSGs) and debridement operations were included (p=0.034, CI 95%). No differences were found in crystalloid use, intraoperative temperature, pre-operative haemoglobin and blood products or vasopressor use. This analysis highlights an independent association between colloids and graft failure which has not been previously documented.

Psychological Predictors of Visual and Auditory P300 Brain-Computer Interface Performance

PubMed Central

Hammer, Eva M.; Halder, Sebastian; Kleih, Sonja C.; Kübler, Andrea

2018-01-01

Brain-Computer Interfaces (BCIs) provide communication channels independent from muscular control. In the current study we used two versions of the P300-BCI: one based on visual the other on auditory stimulation. Up to now, data on the impact of psychological variables on P300-BCI control are scarce. Hence, our goal was to identify new predictors with a comprehensive psychological test-battery. A total of N = 40 healthy BCI novices took part in a visual and an auditory BCI session. Psychological variables were measured with an electronic test-battery including clinical, personality, and performance tests. The personality factor “emotional stability” was negatively correlated (Spearman's rho = −0.416; p < 0.01) and an output variable of the non-verbal learning test (NVLT), which can be interpreted as ability to learn, correlated positively (Spearman's rho = 0.412; p < 0.01) with visual P300-BCI performance. In a linear regression analysis both independent variables explained 24% of the variance. “Emotional stability” was also negatively related to auditory P300-BCI performance (Spearman's rho = −0.377; p < 0.05), but failed significance in the regression analysis. Psychological parameters seem to play a moderate role in visual P300-BCI performance. “Emotional stability” was identified as a new predictor, indicating that BCI users who characterize themselves as calm and rational showed worse BCI performance. The positive relation of the ability to learn and BCI performance corroborates the notion that also for P300 based BCIs learning may constitute an important factor. Further studies are needed to consolidate or reject the presented predictors. PMID:29867319

Climate change but not unemployment explains the changing suicidality in Thessaloniki Greece (2000-2012).

PubMed

Fountoulakis, Konstantinos N; Savopoulos, Christos; Zannis, Prodromos; Apostolopoulou, Martha; Fountoukidis, Ilias; Kakaletsis, Nikolaos; Kanellos, Ilias; Dimellis, Dimos; Hyphantis, Thomas; Tsikerdekis, Athanasios; Pompili, Maurizio; Hatzitolios, Apostolos I

2016-03-15

Recently there was a debate concerning the etiology behind attempts and completed suicides. The aim of the current study was to search for possible correlations between the rates of attempted and completed suicide and climate variables and regional unemployment per year in the county of Thessaloniki, Macedonia, northern Greece, for the years 2000-12. The regional rates of suicide and attempted suicide as well as regional unemployment were available from previous publications of the authors. The climate variables were calculated from the daily E-OBS gridded dataset which is based on observational data Only the male suicide rates correlate significantly with high mean annual temperature but not with unemployment. The multiple linear regression analysis results suggest that temperature is the only variable that determines male suicides and explains 51% of their variance. Unemployment fails to contribute significantly to the model. There seems to be a seasonal distribution for attempts with mean rates being higher for the period from May to October and the rates clearly correlate with temperature. The highest mean rates were observed during May and August and the lowest during December and February. Multiple linear regression analysis suggests that temperature also determines the female attempts rate although the explained variable is significant but very low (3-5%) Climate variables and specifically high temperature correlate both with suicide and attempted suicide rates but with a different way between males and females. The climate effect was stronger than the effect of unemployment. Copyright © 2016 Elsevier B.V. All rights reserved.

Understanding the management and teaching of dental restoration repair: Systematic review and meta-analysis of surveys.

PubMed

Kanzow, Philipp; Wiegand, Annette; Göstemeyer, Gerd; Schwendicke, Falk

2018-02-01

Repair instead of complete replacement is recommended to manage partially defective restorations. It is unclear if and why such treatment is taught at dental schools or practiced by dentists. We aimed to identify barriers and facilitators for repairs using a systematic review and meta- and qualitative analysis. Electronic databases (PubMed, CENTRAL, Embase, PsycINFO) were searched. Quantitative studies reporting on the proportion of (1) dentists stating to perform repairs, (2) dental schools teaching repairs, (3) failed restorations having been repaired were included. We also included qualitative studies on barriers/facilitators for repairs. Random-effects meta-analyses, meta-regression and a thematic analysis using the theoretical domains framework were conducted. 401 articles were assessed and 29, mainly quantitative, studies included. 7228 dentists and 276 dental schools had been surveyed, and treatment data of 30,172 restorations evaluated. The mean (95% CI) proportion of dentists stating to perform repairs was 71.5% (49.7-86.4%). 83.3% (73.6-90.0%) of dental schools taught repairs. 31.3% (26.3-36.7%) of failed restorations had been repaired. More recent studies reported significantly more dentists to repair restorations (p=0.004). Employment in public health practices and being the dentist who placed the original restoration were facilitators for repairs. Amalgam restorations were repaired less often, and financial aspects and regulations came as barriers. While most dentists state to perform repairs and the vast majority of dental schools teach repairs, the proportion of truly repaired restorations was low. A number of interventions to implement repair in dental practice can be deduced from our findings. Partially defective restorations are common in dental practice. While repairs are taught and dentists are aware of the recommendation towards repairs, the actually performed proportion of repairs seems low. Copyright © 2017 Elsevier Ltd. All rights reserved.

Poor-quality antimalarial drugs in southeast Asia and sub-Saharan Africa.

PubMed

Nayyar, Gaurvika M L; Breman, Joel G; Newton, Paul N; Herrington, James

2012-06-01

Poor-quality antimalarial drugs lead to drug resistance and inadequate treatment, which pose an urgent threat to vulnerable populations and jeopardise progress and investments in combating malaria. Emergence of artemisinin resistance or tolerance in Plasmodium falciparum on the Thailand-Cambodia border makes protection of the effectiveness of the drug supply imperative. We reviewed published and unpublished studies reporting chemical analyses and assessments of packaging of antimalarial drugs. Of 1437 samples of drugs in five classes from seven countries in southeast Asia, 497 (35%) failed chemical analysis, 423 (46%) of 919 failed packaging analysis, and 450 (36%) of 1260 were classified as falsified. In 21 surveys of drugs from six classes from 21 countries in sub-Saharan Africa, 796 (35%) of 2297 failed chemical analysis, 28 (36%) of 77 failed packaging analysis, and 79 (20%) of 389 were classified as falsified. Data were insufficient to identify the frequency of substandard (products resulting from poor manufacturing) antimalarial drugs, and packaging analysis data were scarce. Concurrent interventions and a multifaceted approach are needed to define and eliminate criminal production, distribution, and poor manufacturing of antimalarial drugs. Empowering of national medicine regulatory authorities to protect the global drug supply is more important than ever. Copyright © 2012 Elsevier Ltd. All rights reserved.

Principal component regression analysis with SPSS.

PubMed

Liu, R X; Kuang, J; Gong, Q; Hou, X L

2003-06-01

The paper introduces all indices of multicollinearity diagnoses, the basic principle of principal component regression and determination of 'best' equation method. The paper uses an example to describe how to do principal component regression analysis with SPSS 10.0: including all calculating processes of the principal component regression and all operations of linear regression, factor analysis, descriptives, compute variable and bivariate correlations procedures in SPSS 10.0. The principal component regression analysis can be used to overcome disturbance of the multicollinearity. The simplified, speeded up and accurate statistical effect is reached through the principal component regression analysis with SPSS.

Multivariate analysis of risk factors for long-term urethroplasty outcome.

PubMed

Breyer, Benjamin N; McAninch, Jack W; Whitson, Jared M; Eisenberg, Michael L; Mehdizadeh, Jennifer F; Myers, Jeremy B; Voelzke, Bryan B

2010-02-01

We studied the patient risk factors that promote urethroplasty failure. Records of patients who underwent urethroplasty at the University of California, San Francisco Medical Center between 1995 and 2004 were reviewed. Cox proportional hazards regression analysis was used to identify multivariate predictors of urethroplasty outcome. Between 1995 and 2004, 443 patients of 495 who underwent urethroplasty had complete comorbidity data and were included in analysis. Median patient age was 41 years (range 18 to 90). Median followup was 5.8 years (range 1 month to 10 years). Stricture recurred in 93 patients (21%). Primary estimated stricture-free survival at 1, 3 and 5 years was 88%, 82% and 79%. After multivariate analysis smoking (HR 1.8, 95% CI 1.0-3.1, p = 0.05), prior direct vision internal urethrotomy (HR 1.7, 95% CI 1.0-3.0, p = 0.04) and prior urethroplasty (HR 1.8, 95% CI 1.1-3.1, p = 0.03) were predictive of treatment failure. On multivariate analysis diabetes mellitus showed a trend toward prediction of urethroplasty failure (HR 2.0, 95% CI 0.8-4.9, p = 0.14). Length of urethral stricture (greater than 4 cm), prior urethroplasty and failed endoscopic therapy are predictive of failure after urethroplasty. Smoking and diabetes mellitus also may predict failure potentially secondary to microvascular damage. Copyright 2010 American Urological Association. Published by Elsevier Inc. All rights reserved.

Characteristics of Pediatric Performance on a Test Battery Commonly Used in the Diagnosis of Central Auditory Processing Disorder.

PubMed

Weihing, Jeffrey; Guenette, Linda; Chermak, Gail; Brown, Mallory; Ceruti, Julianne; Fitzgerald, Krista; Geissler, Kristin; Gonzalez, Jennifer; Brenneman, Lauren; Musiek, Frank

2015-01-01

Although central auditory processing disorder (CAPD) test battery performance has been examined in adults with neurologic lesions of the central auditory nervous system (CANS), similar data on children being referred for CAPD evaluations are sparse. This study characterizes CAPD test battery performance in children using tests commonly administered to diagnose the disorder. Specifically, this study describes failure rates for various test combinations, relationships between CAPD tests used in the battery, and the influence of cognitive function on CAPD test performance and CAPD diagnosis. A comparison is also made between the performance of children with CAPD and data from patients with neurologic lesions of the CANS. A retrospective study. Fifty-six pediatric patients were referred for CAPD testing. Participants were administered four CAPD tests, including frequency patterns (FP), low-pass filtered speech (LPFS), dichotic digits (DD), and competing sentences (CS). In addition, they were given the Wechsler Intelligence Scale for Children (WISC). Descriptive analyses examined the failure rates of various test combinations, as well as how often children with CAPD failed certain combinations when compared with adults with CANS lesions. A principal components analysis was performed to examine interrelationships between tests. Correlations and regressions were conducted to determine the relationship between CAPD test performance and the WISC. Results showed that the FP and LPFS tests were most commonly failed by children with CAPD. Two-test combinations that included one or both of these two tests and excluded DD tended to be failed more often. Including the DD and CS test in a battery benefited specificity. Tests thought to measure interhemispheric transfer tended to be correlated. Compared with adult patients with neurologic lesions, children with CAPD tended to fail LPFS more frequently and DD less frequently. Both groups failed FP with relatively equal frequency. The two-test combination that showed the highest failure rate for children with CAPD was LPFS-FP. Comparison with adults with CANS lesions, however, suggests that the mechanisms underlying LPFS performance in children need to be better understood. The two-test combination that showed the next highest failure rates among children with CAPD and did not include LPFS was CS-FP. If it is desirable to use a dichotic measure that has a lower linguistic load than CS then DD can be substituted for CS despite the slightly lower failure rate of the DD-FP battery. American Academy of Audiology.

Binomial outcomes in dataset with some clusters of size two: can the dependence of twins be accounted for? A simulation study comparing the reliability of statistical methods based on a dataset of preterm infants.

PubMed

Sauzet, Odile; Peacock, Janet L

2017-07-20

The analysis of perinatal outcomes often involves datasets with some multiple births. These are datasets mostly formed of independent observations and a limited number of clusters of size two (twins) and maybe of size three or more. This non-independence needs to be accounted for in the statistical analysis. Using simulated data based on a dataset of preterm infants we have previously investigated the performance of several approaches to the analysis of continuous outcomes in the presence of some clusters of size two. Mixed models have been developed for binomial outcomes but very little is known about their reliability when only a limited number of small clusters are present. Using simulated data based on a dataset of preterm infants we investigated the performance of several approaches to the analysis of binomial outcomes in the presence of some clusters of size two. Logistic models, several methods of estimation for the logistic random intercept models and generalised estimating equations were compared. The presence of even a small percentage of twins means that a logistic regression model will underestimate all parameters but a logistic random intercept model fails to estimate the correlation between siblings if the percentage of twins is too small and will provide similar estimates to logistic regression. The method which seems to provide the best balance between estimation of the standard error and the parameter for any percentage of twins is the generalised estimating equations. This study has shown that the number of covariates or the level two variance do not necessarily affect the performance of the various methods used to analyse datasets containing twins but when the percentage of small clusters is too small, mixed models cannot capture the dependence between siblings.

Kinetic therapy in multiple trauma patients with severe blunt chest trauma: an analysis at a level-1 trauma center.

PubMed

Zeckey, C; Wendt, K; Mommsen, P; Winkelmann, M; Frömke, C; Weidemann, J; Stübig, T; Krettek, C; Hildebrand, F

2015-01-01

Chest trauma is a relevant risk factor for mortality after multiple trauma. Kinetic therapy (KT) represents a potential treatment option in order to restore pulmonary function. Decision criteria for performing kinetic therapy are not fully elucidated. The purpose of this study was to investigate the decision making process to initiate kinetic therapy in a well defined multiple trauma cohort. A retrospective analysis (2000-2009) of polytrauma patients (age > 16 years, ISS ⩾ 16) with severe chest trauma (AIS(Chest) ⩾ 3) was performed. Patients with AIS(Head) ⩾ 3 were excluded. Patients receiving either kinetic (KT+) or lung protective ventilation strategy (KT-) were compared. Chest trauma was classified according to the AIS(Chest), Pulmonary Contusion Score (PCS), Wagner Jamieson Score and Thoracic Trauma Severity Score (TTS). There were multiple outcome parameters investigated included mortality, posttraumatic complications and clinical data. A multivariate regression analysis was performed. Two hundred and eighty-three patients were included (KT+: n=160; KT-: n=123). AIS(Chest), age and gender were comparable in both groups. There were significant higher values of the ISS, PCS, Wagner Jamieson Score and TTS in group KT+. The incidence of posttraumatic complications and mortality was increased compared to group KT- (p< 0.05). Despite that, kinetic therapy failed to be an independent risk factor for mortality in multivariate logistic regression analysis. Kinetic therapy is an option in severely injured patients with severe chest trauma. Decision making is not only based on anatomical aspects such as the AIS(Chest), but on overall injury severity, pulmonary contusions and physiological deterioration. It could be assumed that the increased mortality in patients receiving KT is primarily caused by these factors and does not reflect an independent adverse effect of KT. Furthermore, KT was not shown to be an independent risk factor for mortality.

Actomyosin contractility regulators stabilize the cytoplasmic bridge between the two primordial germ cells during Caenorhabditis elegans embryogenesis.

PubMed

Goupil, Eugénie; Amini, Rana; Hall, David H; Labbé, Jean-Claude

2017-12-15

Stable cytoplasmic bridges arise from failed cytokinesis, the last step of cell division, and are a key feature of syncytial architectures in the germline of most metazoans. Whereas the Caenorhabditis elegans germline is syncytial, its formation remains poorly understood. We found that the germline precursor blastomere, P 4 , fails cytokinesis, leaving a stable cytoplasmic bridge between the two daughter cells, Z 2 and Z 3 Depletion of several regulators of actomyosin contractility resulted in a regression of the membrane partition between Z 2 and Z 3 , indicating that they are required to stabilize the cytoplasmic bridge. Epistatic analysis revealed a pathway in which Rho regulators promote accumulation of the nonc annonical anillin ANI-2 at the stable cytoplasmic bridge, which in turns promotes the accumulation of the nonm uscle myosin II NMY-2 and the midbody component CYK-7 at the bridge, in part by limiting the accumulation of canonical anillin ANI-1. Our results uncover key steps in C. elegans germline formation and define a set of conserved regulators that are enriched at the primordial germ cell cytoplasmic bridge to ensure its stability during embryonic development. © 2017 Goupil, Amini, et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

Relationships between weather and myocardial infarction: a biometeorological approach.

PubMed

Morabito, Marco; Modesti, Pietro Amedeo; Cecchi, Lorenzo; Crisci, Alfonso; Orlandini, Simone; Maracchi, Giampiero; Gensini, Gian Franco

2005-12-07

To calculate threshold values of weather discomfort which increase the risk of hospital admissions for myocardial infarction in winter and summer. Notwithstanding heat waves were reported to acutely increase hospital admissions for cardiovascular diseases, large surveys failed to reveal any increase of event rates with increasing air temperature. However, the assessment of air temperature does not allow evaluation of the actual discomfort perception caused by the combination of different meteorological parameters. Hospital admissions for myocardial infarction for the period 1998-2002 in Florence, Italy, were considered. The percentages of variation of daily event rates according to daily mean air temperature variations were preliminary derived by using a regression analysis. An alternative biometeorological approach, considering the Apparent Temperature Index (ATI) in summer, and the New U.S./Canada Wind Chill Temperature Index (NWCTI) in winter, which combine air temperature, relative humidity and wind velocity, was then used. The traditional approach showed that daily event rates significantly increased with daily mean air temperature decrease (10 degrees C decrease were associated with 19% increase in daily event rates for people older than 65 years), but failed to show any negative effect caused by hot climatic conditions. Conversely the biometeorological approach allowed to show that at least 9 h per day of severe discomfort caused by hot conditions significantly increased the rate of admission (P<0.01). This approach might be useful for the development of an operative weather watch/warning system for population and for hospital professional care.

Spatial and temporal variability in rates of landsliding in seismically active mountain ranges

NASA Astrophysics Data System (ADS)

Parker, R.; Petley, D.; Rosser, N.; Densmore, A.; Gunasekera, R.; Brain, M.

2012-04-01

Where earthquake and precipitation driven disasters occur in steep, mountainous regions, landslides often account for a large proportion of the associated damage and losses. This research addresses spatial and temporal variability in rates of landslide occurrence in seismically active mountain ranges as a step towards developing better regional scale prediction of losses in such events. In the first part of this paper we attempt to explain reductively the variability in spatial rates of landslide occurrence, using data from five major earthquakes. This is achieved by fitting a regression-based conditional probability model to spatial probabilities of landslide occurrence, using as predictor variables proxies for spatial patterns of seismic ground motion and modelled hillslope stability. A combined model for all earthquakes performs well in hindcasting spatial probabilities of landslide occurrence as a function of readily-attainable spatial variables. We present validation of the model and demonstrate the extent to which it may be applied globally to derive landslide probabilities for future earthquakes. In part two we examine the temporal behaviour of rates of landslide occurrence. This is achieved through numerical modelling to simulate the behaviour of a hypothetical landscape. The model landscape is composed of hillslopes that continually weaken, fail and reset in response to temporally-discrete forcing events that represent earthquakes. Hillslopes with different geometries require different amounts of weakening to fail, such that they fail and reset at different temporal rates. Our results suggest that probabilities of landslide occurrence are not temporally constant, but rather vary with time, irrespective of changes in forcing event magnitudes or environmental conditions. Various parameters influencing the magnitude and temporal patterns of this variability are identified, highlighting areas where future research is needed. This model has important implications for landslide hazard and risk analysis in mountain areas as existing techniques usually assume that susceptibility to failure does not change with time.

Patterns of reoperation after failed fundoplication: an analysis of 9462 patients.

PubMed

Obeid, Nabeel R; Altieri, Maria S; Yang, Jie; Park, Jihye; Price, Kristie; Bates, Andrew; Pryor, Aurora D

2018-01-01

Little is known about the choice of reoperation after failed fundoplication for gastroesophageal reflux disease. Both redo fundoplication and conversion procedure to Roux-en-Y gastric bypass (RYGB) are safe and effective. We aimed to characterize the rates of different revisional procedures and to identify risk factors associated with failed fundoplication. Using a statewide database, we examined records for patients who underwent fundoplication between 2000 and 2010. The primary outcomes were the rate of each type of reoperation and the pattern of subsequent procedures. Demographics and comorbidities were used in a multivariable logistic regression model to identify risk factors associated with reoperation after fundoplication. A total of 9462 patients were included. Overall, 430 (4.5%) patients underwent reoperation. Of those, 46 (10.7%) patients underwent RYGB at first reoperation, with the remainder having a redo fundoplication. An additional five patients were converted to RYGB after undergoing a redo fundoplication (51 total patients converted to RYGB at any point, 11.9%). Eighty-three percent of patients converted to RYGB were obese, as opposed to 8% for redo fundoplication. A single redo fundoplication was done in 81% of patients, while 35 patients (8.1%) underwent two or more revisional procedures. On average, any reoperation was performed 2.9 years after fundoplication, with redo fundoplication 2.5 years and RYGB 6.5 years later. Age 30-49 years (vs. >70 years; OR 2.01, p = 0.011) and 50-69 years (vs. >70 years; OR 1.61, p = 0.011), female gender (OR 1.56, p = < 0.0001), and chronic pulmonary disease (OR 1.40, p = 0.0044) were associated with revisional surgery. Fundoplication has a low reoperation rate within a mean 8.3 years of follow-up. Redo fundoplication is more commonly performed and at an earlier point than conversion to RYGB. Younger age, female gender, and chronic pulmonary disease are associated with reoperation after fundoplication.

Army Physical Therapy Productivity According to the Performance Based Adjustment Model

DTIC Science & Technology

2008-05-02

variation in processes often fell along a bell shaped curve or normal distribution. Shewart later developed a control chart to track and analyze variation in...References Abdi, H. (2003). Partial regression coefficients. In M. Lewis-Beck, A . Bryman & T. Futing (Eds.), Encyclopedia of Social Sciences Research...other provision of law. no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a

[Fractographic analysis of clinically failed anterior all ceramic crowns].

PubMed

DU, Qian; Zhou, Min-bo; Zhang, Xin-ping; Zhao, Ke

2012-04-01

To identify the site of crack initiation and propagation path of clinically failed all ceramic crowns by fractographic analysis. Three clinically failed anterior IPS Empress II crowns and two anterior In-Ceram alumina crowns were retrieved. Fracture surfaces were examined using both optical stereo and scanning electron microscopy. Fractographic theory and fracture mechanics principles were applied to disclose the damage characteristics and fracture mode. All the crowns failed by cohesive failure within the veneer on the labial surface. Critical crack originated at the incisal contact area and propagated gingivally. Porosity was found within the veneer because of slurry preparation and the sintering of veneer powder. Cohesive failure within the veneer is the main failure mode of all ceramic crown. Veneer becomes vulnerable when flaws are present. To reduce the chances of chipping, multi-point occlusal contacts are recommended, and layering and sintering technique of veneering layer should also be improved.

Regression Analysis by Example. 5th Edition

ERIC Educational Resources Information Center

Chatterjee, Samprit; Hadi, Ali S.

2012-01-01

Regression analysis is a conceptually simple method for investigating relationships among variables. Carrying out a successful application of regression analysis, however, requires a balance of theoretical results, empirical rules, and subjective judgment. "Regression Analysis by Example, Fifth Edition" has been expanded and thoroughly…

Classifying Failing States

DTIC Science & Technology

2007-03-01

state failure, and Discriminant Analysis to classify states as Stable, Borderline, or Failing based on these indicators. Furthermore, each...nation’s discriminant function scores are used to determine their degree of instability. The methodology is applied to 200 countries for which open source...and go for a long walk. Finally, to my wonderful wife, who now knows more about Discriminant Analysis than any Legal Assistant on the planet, thank

Breast Cancer and Women's Labor Supply

PubMed Central

Bradley, Cathy J; Bednarek, Heather L; Neumark, David

2002-01-01

Objective To investigate the effect of breast cancer on women's labor supply. Date Source/Study Setting Using the 1992 Health and Retirement Study, we estimate the probability of working using probit regression and then, for women who are employed, we estimate regressions for average weekly hours worked using ordinary least squares (OLS). We control for health status by using responses to perceived health status and comorbidities. For a sample of married women, we control for spouses' employer-based health insurance. We also perform additional analyses to detect selection bias in our sample. Principal Findings We find that the probability of breast cancer survivors working is 10 percentage points less than that for women without breast cancer. Among women who work, breast cancer survivors work approximately three more hours per week than women who do not have cancer. Results of similar magnitude persist after health status is controlled in the analysis, and although we could not definitively rule out selection bias, we could not find evidence that our results are attributable to selection bias. Conclusions For some women, breast cancer may impose an economic hardship because it causes them to leave their jobs. However, for women who survive and remain working, this study failed to show a negative effect on hours worked associated with breast cancer. Perhaps the morbidity associated with certain types and stages of breast cancer and its treatment does not interfere with work. PMID:12479498

Risk Factors for Post-Transplant Death in Donation after Circulatory Death Liver Transplantation.

PubMed

Liu, Song; Miao, Ji; Shi, Xiaolei; Wu, Yafu; Jiang, Chunping; Zhu, Xinhua; Wu, Xingyu; Ding, Yitao; Xu, Qingxiang

2017-08-22

In spite of the increasing success of liver transplantation, there remains inevitable risk of postoperative complications, re-operations, and even death. Risk factors that correlate with post-transplant death have not been fully identified. We performed a retrospective analysis of 65 adults that received donation after circulatory death liver transplantation. Binary logistic regression and Cox's proportional hazards regression were employed to identify risk factors that associate with postoperative death and the length of survival period. Twenty-two recipients (33.8%) deceased during 392.3 ± 45.6 days. The higher preoperative Child-Pugh score (p = .007), prolonged postoperative ICU stay (p = .02), and more postoperative complications (p = .0005) were observed in deceased patients. Advanced pathological staging (p = .02) with more common nerve invasion (p = .03), lymph node invasion (p = .02), and para-tumor satellite lesion (p = .01) were found in deceased group. The higher pre-transplant Child-Pugh score was a risk factor for post-transplant death (OR = 4.38, p = .011), and was correlated with reduced post-transplant survival period (OR = 0.35, p = .009). Nerve invasion was also a risk factor for post-transplant death (OR = 13.85, p = .014), although it failed to affect survival period. Our study emphasizes the impact of recipient's pre-transplant liver function as well as pre-transplant nerve invasion by recipient's liver cancer cells on postoperative outcome and survival period in patients receiving liver transplantation.

Mechanistic analysis of challenge-response experiments.

PubMed

Shotwell, M S; Drake, K J; Sidorov, V Y; Wikswo, J P

2013-09-01

We present an application of mechanistic modeling and nonlinear longitudinal regression in the context of biomedical response-to-challenge experiments, a field where these methods are underutilized. In this type of experiment, a system is studied by imposing an experimental challenge, and then observing its response. The combination of mechanistic modeling and nonlinear longitudinal regression has brought new insight, and revealed an unexpected opportunity for optimal design. Specifically, the mechanistic aspect of our approach enables the optimal design of experimental challenge characteristics (e.g., intensity, duration). This article lays some groundwork for this approach. We consider a series of experiments wherein an isolated rabbit heart is challenged with intermittent anoxia. The heart responds to the challenge onset, and recovers when the challenge ends. The mean response is modeled by a system of differential equations that describe a candidate mechanism for cardiac response to anoxia challenge. The cardiac system behaves more variably when challenged than when at rest. Hence, observations arising from this experiment exhibit complex heteroscedasticity and sharp changes in central tendency. We present evidence that an asymptotic statistical inference strategy may fail to adequately account for statistical uncertainty. Two alternative methods are critiqued qualitatively (i.e., for utility in the current context), and quantitatively using an innovative Monte-Carlo method. We conclude with a discussion of the exciting opportunities in optimal design of response-to-challenge experiments. © 2013, The International Biometric Society.

Bayesian quantile regression-based partially linear mixed-effects joint models for longitudinal data with multiple features.

PubMed

Zhang, Hanze; Huang, Yangxin; Wang, Wei; Chen, Henian; Langland-Orban, Barbara

2017-01-01

In longitudinal AIDS studies, it is of interest to investigate the relationship between HIV viral load and CD4 cell counts, as well as the complicated time effect. Most of common models to analyze such complex longitudinal data are based on mean-regression, which fails to provide efficient estimates due to outliers and/or heavy tails. Quantile regression-based partially linear mixed-effects models, a special case of semiparametric models enjoying benefits of both parametric and nonparametric models, have the flexibility to monitor the viral dynamics nonparametrically and detect the varying CD4 effects parametrically at different quantiles of viral load. Meanwhile, it is critical to consider various data features of repeated measurements, including left-censoring due to a limit of detection, covariate measurement error, and asymmetric distribution. In this research, we first establish a Bayesian joint models that accounts for all these data features simultaneously in the framework of quantile regression-based partially linear mixed-effects models. The proposed models are applied to analyze the Multicenter AIDS Cohort Study (MACS) data. Simulation studies are also conducted to assess the performance of the proposed methods under different scenarios.

Neural net controlled tag gas sampling system for nuclear reactors

DOEpatents

Gross, Kenneth C.; Laug, Matthew T.; Lambert, John D. B.; Herzog, James P.

1997-01-01

A method and system for providing a tag gas identifier to a nuclear fuel rod and analyze escaped tag gas to identify a particular failed nuclear fuel rod. The method and system include disposing a unique tag gas composition into a plenum of a nuclear fuel rod, monitoring gamma ray activity, analyzing gamma ray signals to assess whether a nuclear fuel rod has failed and is emitting tag gas, activating a tag gas sampling and analysis system upon sensing tag gas emission from a failed nuclear rod and evaluating the escaped tag gas to identify the particular failed nuclear fuel rod.

Catchments as non-linear filters: evaluating data-driven approaches for spatio-temporal predictions in ungauged basins

NASA Astrophysics Data System (ADS)

Bellugi, D. G.; Tennant, C.; Larsen, L.

2016-12-01

Catchment and climate heterogeneity complicate prediction of runoff across time and space, and resulting parameter uncertainty can lead to large accumulated errors in hydrologic models, particularly in ungauged basins. Recently, data-driven modeling approaches have been shown to avoid the accumulated uncertainty associated with many physically-based models, providing an appealing alternative for hydrologic prediction. However, the effectiveness of different methods in hydrologically and geomorphically distinct catchments, and the robustness of these methods to changing climate and changing hydrologic processes remain to be tested. Here, we evaluate the use of machine learning techniques to predict daily runoff across time and space using only essential climatic forcing (e.g. precipitation, temperature, and potential evapotranspiration) time series as model input. Model training and testing was done using a high quality dataset of daily runoff and climate forcing data for 25+ years for 600+ minimally-disturbed catchments (drainage area range 5-25,000 km2, median size 336 km2) that cover a wide range of climatic and physical characteristics. Preliminary results using Support Vector Regression (SVR) suggest that in some catchments this nonlinear-based regression technique can accurately predict daily runoff, while the same approach fails in other catchments, indicating that the representation of climate inputs and/or catchment filter characteristics in the model structure need further refinement to increase performance. We bolster this analysis by using Sparse Identification of Nonlinear Dynamics (a sparse symbolic regression technique) to uncover the governing equations that describe runoff processes in catchments where SVR performed well and for ones where it performed poorly, thereby enabling inference about governing processes. This provides a robust means of examining how catchment complexity influences runoff prediction skill, and represents a contribution towards the integration of data-driven inference and physically-based models.

Comparison of Regression Methods to Compute Atmospheric Pressure and Earth Tidal Coefficients in Water Level Associated with Wenchuan Earthquake of 12 May 2008

NASA Astrophysics Data System (ADS)

He, Anhua; Singh, Ramesh P.; Sun, Zhaohua; Ye, Qing; Zhao, Gang

2016-07-01

The earth tide, atmospheric pressure, precipitation and earthquake fluctuations, especially earthquake greatly impacts water well levels, thus anomalous co-seismic changes in ground water levels have been observed. In this paper, we have used four different models, simple linear regression (SLR), multiple linear regression (MLR), principal component analysis (PCA) and partial least squares (PLS) to compute the atmospheric pressure and earth tidal effects on water level. Furthermore, we have used the Akaike information criterion (AIC) to study the performance of various models. Based on the lowest AIC and sum of squares for error values, the best estimate of the effects of atmospheric pressure and earth tide on water level is found using the MLR model. However, MLR model does not provide multicollinearity between inputs, as a result the atmospheric pressure and earth tidal response coefficients fail to reflect the mechanisms associated with the groundwater level fluctuations. On the premise of solving serious multicollinearity of inputs, PLS model shows the minimum AIC value. The atmospheric pressure and earth tidal response coefficients show close response with the observation using PLS model. The atmospheric pressure and the earth tidal response coefficients are found to be sensitive to the stress-strain state using the observed data for the period 1 April-8 June 2008 of Chuan 03# well. The transient enhancement of porosity of rock mass around Chuan 03# well associated with the Wenchuan earthquake (Mw = 7.9 of 12 May 2008) that has taken its original pre-seismic level after 13 days indicates that the co-seismic sharp rise of water well could be induced by static stress change, rather than development of new fractures.

Role of Adjuvant Chemotherapy in ypT0-2N0 Patients Treated with Preoperative Chemoradiation Therapy and Radical Resection for Rectal Cancer.

PubMed

Park, In Ja; Kim, Dae Yong; Kim, Hee Cheol; Kim, Nam Kyu; Kim, Hyeong-Rok; Kang, Sung-Bum; Choi, Gyu-Seog; Lee, Kang Young; Kim, Seon-Hahn; Oh, Seung Taek; Lim, Seok-Byung; Kim, Jin Cheon; Oh, Jae Hwan; Kim, Sun Young; Lee, Woo Yong; Lee, Jung Bok; Yu, Chang Sik

2015-07-01

To explore the role of adjuvant chemotherapy for patients with ypT0-2N0 rectal cancer treated by preoperative chemoradiation therapy (PCRT) and radical resection. A national consortium of 10 institutions was formed, and patients with ypT0-2N0 mid- and low-rectal cancer after PCRT and radical resection from 2004 to 2009 were included. Patients were categorized into 2 groups according to receipt of additional adjuvant chemotherapy: Adj CTx (+) versus Adj CTx (-). Propensity scores were calculated and used to perform matched and adjusted analyses comparing relapse-free survival (RFS) between treatment groups while controlling for potential confounding. A total of 1016 patients, who met the selection criteria, were evaluated. Of these, 106 (10.4%) did not receive adjuvant chemotherapy. There was no overall improvement in 5-year RFS as a result of adjuvant chemotherapy [91.6% for Adj CTx (+) vs 87.5% for Adj CTx (-), P=.18]. There were no differences in 5-year local recurrence and distant metastasis rate between the 2 groups. In patients who show moderate, minimal, or no regression in tumor regression grade, however, possible association of adjuvant chemotherapy with RFS would be considered (hazard ratio 0.35; 95% confidence interval 0.14-0.88; P=.03). Cox regression analysis after propensity score matching failed to show that addition of adjuvant chemotherapy was associated with improved RFS (hazard ratio 0.81; 95% confidence interval 0.39-1.70; P=.58). Adjuvant chemotherapy seemed to not influence the RFS of patients with ypT0-2N0 rectal cancer after PCRT followed by radical resection. Thus, the addition of adjuvant chemotherapy needs to be weighed against its oncologic benefits. Copyright © 2015 Elsevier Inc. All rights reserved.

The failure to fail underperforming trainees in health professions education: A BEME systematic review: BEME Guide No. 42.

PubMed

Yepes-Rios, Monica; Dudek, Nancy; Duboyce, Rita; Curtis, Jerri; Allard, Rhonda J; Varpio, Lara

2016-11-01

Many clinical educators feel unprepared and/or unwilling to report unsatisfactory trainee performance. This systematic review consolidates knowledge from medical, nursing, and dental literature on the experiences and perceptions of evaluators or assessors with this failure to fail phenomenon. We searched the English language literature in CINAHL, EMBASE, and MEDLINE from January 2005 to January 2015. Qualitative and quantitative studies were included. Following our review protocol, registered with BEME, reviewers worked in pairs to identify relevant articles. The investigators participated in thematic analysis of the qualitative data reported in these studies. Through several cycles of analysis, discussion and reflection, the team identified the barriers and enablers to failing a trainee. From 5330 articles, we included 28 publications in the review. The barriers identified were (1) assessor's professional considerations, (2) assessor's personal considerations, (3) trainee related considerations, (4) unsatisfactory evaluator development and evaluation tools, (5) institutional culture and (6) consideration of available remediation for the trainee. The enablers identified were: (1) duty to patients, to society, and to the profession, (2) institutional support such as backing a failing evaluation, support from colleagues, evaluator development, and strong assessment systems, and (3) opportunities for students after failing. The inhibiting and enabling factors to failing an underperforming trainee were common across the professions included in this study, across the 10 years of data, and across the educational continuum. We suggest that these results can inform efforts aimed at addressing the failure to fail problem.

Defining the molecular signatures of human right heart failure.

PubMed

Williams, Jordan L; Cavus, Omer; Loccoh, Emefah C; Adelman, Sara; Daugherty, John C; Smith, Sakima A; Canan, Benjamin; Janssen, Paul M L; Koenig, Sara; Kline, Crystal F; Mohler, Peter J; Bradley, Elisa A

2018-03-01

Right ventricular failure (RVF) varies significantly from the more common left ventricular failure (LVF). This study was undertaken to determine potential molecular pathways that are important in human right ventricular (RV) function and may mediate RVF. We analyzed mRNA of human non-failing LV and RV samples and RVF samples from patients with pulmonary arterial hypertension (PAH), and post-LVAD implantation. We then performed transcript analysis to determine differential expression of genes in the human heart samples. Immunoblot quantification was performed followed by analysis of non-failing and failing phenotypes. Inflammatory pathways were more commonly dysregulated in RV tissue (both non-failing and failing phenotypes). In non-failing human RV tissue we found important differences in expression of FIGF, TRAPPAC, and CTGF suggesting that regulation of normal RV and LV function are not the same. In failing RV tissue, FBN2, CTGF, SMOC2, and TRAPP6AC were differentially expressed, and are potential targets for further study. This work provides some of the first analyses of the molecular heterogeneity between human RV and LV tissue, as well as key differences in human disease (RVF secondary to pulmonary hypertension and LVAD mediated RVF). Our transcriptional data indicated that inflammatory pathways may be more important in RV tissue, and changes in FIGF and CTGF supported this hypothesis. In PAH RV failure samples, upregulation of FBN2 and CTGF further reinforced the potential significance that altered remodeling and inflammation play in normal RV function and failure. Copyright © 2018 Elsevier Inc. All rights reserved.

Metabolomic analysis of 92 pulmonary embolism patients from a nested case-control study identifies metabolites associated with adverse clinical outcomes.

PubMed

Zeleznik, O A; Poole, E M; Lindstrom, S; Kraft, P; Van Hylckama Vlieg, A; Lasky-Su, J A; Harrington, L B; Hagan, K; Kim, J; Parry, B A; Giordano, N; Kabrhel, C

2018-03-01

Essentials Risk-stratification often fails to predict clinical deterioration in pulmonary embolism (PE). First-ever high-throughput metabolomics analysis of risk-stratified PE patients. Changes in circulating metabolites reflect a compromised energy metabolism in PE. Metabolites play a key role in the pathophysiology and risk stratification of PE. Background Patients with acute pulmonary embolism (PE) exhibit wide variation in clinical presentation and outcomes. Our understanding of the pathophysiologic mechanisms differentiating low-risk and high-risk PE is limited, so current risk-stratification efforts often fail to predict clinical deterioration and are insufficient to guide management. Objectives To improve our understanding of the physiology differentiating low-risk from high-risk PE, we conducted the first-ever high-throughput metabolomics analysis (843 named metabolites) comparing PE patients across risk strata within a nested case-control study. Patients/methods We enrolled 92 patients diagnosed with acute PE and collected plasma within 24 h of PE diagnosis. We used linear regression and pathway analysis to identify metabolites and pathways associated with PE risk-strata. Results When we compared 46 low-risk with 46 intermediate/high-risk PEs, 50 metabolites were significantly different after multiple testing correction. These metabolites were enriched in the following pathways: tricarboxylic acid (TCA) cycle, fatty acid metabolism (acyl carnitine) and purine metabolism, (hypo)xanthine/inosine containing. Additionally, energy, nucleotide and amino acid pathways were downregulated in intermediate/high-risk PE patients. When we compared 28 intermediate-risk with 18 high-risk PE patients, 41 metabolites differed at a nominal P-value level. These metabolites were enriched in fatty acid metabolism (acyl cholines), and hemoglobin and porphyrin metabolism. Conclusion Our results suggest that high-throughput metabolomics can provide insight into the pathophysiology of PE. Specifically, changes in circulating metabolites reflect compromised energy metabolism in intermediate/high-risk PE patients. These findings demonstrate the important role metabolites play in the pathophysiology of PE and highlight metabolomics as a potential tool for risk stratification of PE. © 2017 International Society on Thrombosis and Haemostasis.

Conservative management of cesarean scar pregnancies: a prospective randomized controlled trial at a single center.

PubMed

Wang, Mingyi; Yang, Zhiling; Li, Yunming; Chen, Biliang; Wang, Jian; Ma, Xiangdong; Wang, Yu

2015-01-01

To assess clinical outcomes related to conservative management of women with cesarean scar pregnancies (CSPs), specifically through uterine artery embolization (UAE) with local and systemic methotrexate (MTX) treatment (UAE-MTX), or ultrasound-guided local and systemic MTX treatment (USG-MTX). Forty-five patients with CSP were randomly allocated to receive UAE-MTX (n = 24) or USG-MTX (n = 21). Participants' clinical outcomes were compared, and clinical characteristics of failed cases were evaluated relative to successful cases. The 2 groups were similar in clinical characteristics, success rate (83.3% cf. 80.9%), time to normalization of serum beta (β) human chorionic gonadotropin (β-hCG), and percentage of patients receiving multiple doses of systemic MTX. However, within the failed cases, the percentages of patients with gestational sac > 5 cm (87.5%), or type II CSP (75.0%) was significantly higher than in the successful cases (13.5% and 18.9%, respectively; P < 0.001, both), without regard to treatment group. According to the logistic regression model, a gestational sac diameter > 5 cm or type II CSP were independent risk factors for failed CSP management (gestational sac > 5 cm: OR 51.87, 95% CI 3.48-775.91, P < 0.01; type II CSP: OR 15.54, 95% CI 1.25-193.36, P < 0.05). The conservative treatments UAE-MTX and USG-MTX were similarly effective in treating CSP patients. Either treatment was likely to fail for CSP patients with gestational sac > 5 cm or type II CSP.

Statistically Controlling for Confounding Constructs Is Harder than You Think

PubMed Central

Westfall, Jacob; Yarkoni, Tal

2016-01-01

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

Chemotherapeutic potential of curcumin-bearing microcells against hepatocellular carcinoma in model animals

PubMed Central

Farazuddin, Mohammad; Dua, Bhavyata; Zia, Qamar; Khan, Aijaz Ahmad; Joshi, Beenu; Owais, Mohammad

2014-01-01

Curcumin (diferuloylmethane) is found in large quantities in the roots of Curcuma longa. It possesses strong antioxidant and anti-inflammatory properties, and inhibits chemically-induced carcinogenesis in the skin, forestomach, colon, and liver. Unfortunately, the poor bioavailability and hydrophobicity of curcumin pose a major hurdle to its use as a potent anticancer agent. To circumvent some of these problems, we developed a novel, dual-core microcell formulation of curcumin. The encapsulation of curcumin in microcells increases its solubility and bioavailability, and facilitates slow release kinetics over extended periods. Besides being safe, these formulations do not bear any toxicity constraints, as revealed by in vitro and in vivo studies. Histopathological analysis revealed that curcumin-bearing microcells helped in regression of hepatocellular carcinoma and the maintenance of cellular architecture in liver tissue. Free curcumin had a very mild effect on cancer suppression. Empty (sham) microcells and microparticles failed to inhibit cancer cells. The novel curcumin formulation was found to suppress hepatocellular carcinoma efficiently in Swiss albino mice. PMID:24627632

Primary central nervous system lymphoma in immunocompetent individuals: a single center experience.

PubMed

Aki, Hilal; Uzunaslan, Didem; Saygin, Caner; Batur, Sebnem; Tuzuner, Nukhet; Kafadar, Ali; Ongoren, Seniz; Oz, Buge

2013-01-01

Primary central nervous system lymphoma (PCNSL) is defined as the involvement of brain, leptomeninges, eyes or spinal cord by non-Hodgkin lymphoma. The role of various prognostic markers in predicting adverse outcome is debated. To investigate the clinical and immunohistochemical findings of immunocompetent PCNSL cases (39 cases) diagnosed at the study center, and evaluate the influence of potential prognostic factors on overall survival (OS) of patients. Data regarding patient characteristics, neuroimaging, pathological and immunohistochemical features and follow-up were obtained from patient records. The influence of potential prognostic parameters on OS was investigated by log-rank test and Cox regression analysis. Patients who received combined chemotherapy and radiotherapy had a significantly better OS when compared to chemotherapy alone. Other variables included in this study were not associated with a significant survival advantage. In this study, we failed to demonstrate a relationship between different clinicopathological variables and OS of patients. Prospective studies with large patient series are needed to investigate other potential prognostic factors.

The perturbation energy: A missing key to understand the “nobleness” of bulk gold

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

Alcántara Ortigoza, Marisol, E-mail: Marisol.AlcantaraOrtigoza@ucf.edu; Stolbov, Sergey, E-mail: Sergey.Stolbov@ucf.edu

2015-05-21

The nobleness of gold surfaces has been appreciated since long before the beginning of recorded history. Yet, the origin of this phenomenon remains open because the so far existing explanations either incorrectly imply that silver should be the noblest metal or would fail to predict the dissolution of Au in aqua regia. Here, based on our analyses of oxygen adsorption, we advance that bulk gold’s unique resistance to oxidation is traced to the large energy cost associated with the perturbation its surfaces undergo upon adsorption of highly electronegative species. This fact is related to the almost totally filled d-band ofmore » Au and relativistic effects, but does not imply that the strength of the adsorbate-Au bond is weak. The magnitude of the structural and charge-density perturbation energy upon adsorption of atomic oxygen—which is largest for Au—is assessed from first-principles calculations and confirmed via a multiple regression analysis of the binding energy of oxygen on metal surfaces.« less

Middle School Friendships and Academic Achievement in Early Adolescence: A Longitudinal Analysis

PubMed Central

Véronneau, Marie-Hélène; Dishion, Thomas J.

2011-01-01

Early adolescence is a critical transition period for the maintenance of academic achievement. One factor that school systems often fail to take into account is the influence of friends on academic achievement during middle school. This study investigated the influence of friends’ characteristics on change in academic achievement from Grade 6 through 8, and the role of students’ own characteristics as moderators of this relationship. The sample included 1,278 participants (698 girls). Linear regressions suggest that students with academically engaged friends may achieve to levels higher than expected in Grade 8. However, when considering the significant, negative influence of friends’ problem behavior, the role of friend's school engagement became nonsignificant. Low-achieving girls who had high-achieving friends in Grade 6 had lower academic achievement than expected by Grade 8. In contrast, high-achieving girls seemed to benefit from having high-achieving friends. Implications for theory and prevention efforts targeting young adolescents are discussed. PMID:21552353

Elevated-temperature application of the IITRI compression test fixture for graphite/polyimide filamentary composites

NASA Technical Reports Server (NTRS)

Raju, B. B.; Camarda, C. J.; Cooper, P. A.

1979-01-01

Seventy-nine graphite/polyimide compression specimens were tested to investigate experimentally the IITRI test method for determining compressive properties of composite materials at room and elevated temperatures (589 K (600 F)). Minor modifications were made to the standard IITRI fixture and a high degree of precision was maintained in specimen fabrication and load alignment. Specimens included four symmetric laminate orientations. Various widths were tested to evaluate the effect of width on measured modulus and strength. In most cases three specimens of each width were tested at room and elevated temperature and a polynomial regression analysis was used to reduce the data. Scatter of replicate tests and back-to-back strain variations were low, and no specimens failed by instability. Variation of specimen width had a negligible effect on the measured ultimate strengths and initial moduli of the specimens. Measured compressive strength and stiffness values were sufficiently high for the material to be considered a usable structural material at temperatures as high as 589 K (600 F).

Parental guidance about drinking: relationship with teenage psychoactive substance use.

PubMed

Miller, Patrick; Plant, Martin

2010-02-01

Parental guidance concerning alcohol was explored using data from a 2007 survey of 2179 UK school students aged 15 and 16 years. Cluster analysis based on questions about parental advice was used to establish seven student groups. Associations between groups, other family background and psychoactive substance use variables were explored. Substance use was least common amongst students whose parents discouraged drinking and those who claimed to have received no parental guidance. The heaviest substance users were teenagers from families with more favourable, tolerant attitudes to alcohol and intoxication and among students who failed to answer the questions about parental guidance. These scored highly on cannabis and other drug use. The cluster in which there was comprehensive discussion with the parents about alcohol use had an intermediate position in relation to substance use. In logistic regressions parental guidance was consistently associated with substance use with several other background variables controlled. Copyright (c) 2009 The Association for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

Organizational learning and continuous quality improvement: examining the impact on nursing home performance.

PubMed

Rondeau, Kent V; Wagar, Terry H

2002-01-01

Interest is growing in learning more about the ability of total quality management and continuous quality improvement (TQM/CQI) initiatives to contribute to the performance of healthcare organizations. A major factor in the successful implementation of TQM/CQI is the seminal contribution of an organization's culture. Many implementation efforts have not succeeded because of a corporate culture that failed to stress broader organizational learning. This may help to explain why some TQM/CQI programs have been unsuccessful in improving healthcare organization performance. Organizational performance variables and organizational learning orientation were assessed in a sample of 181 Canadian long-term care organizations that had implemented a formal TQM/CQI program. Categorical regression analysis shows that, in the absence of a strong corporAte culture that stresses organizational learning and employee development, few performance enhancements are reported. The results of the assessment suggest that a TQM/CQI program without the backing of a strong organizational learning culture may be insufficient to achieve augmented organizational performance.

Home health agency work environments and hospitalizations.

PubMed

Jarrín, Olga; Flynn, Linda; Lake, Eileen T; Aiken, Linda H

2014-10-01

An important goal of home health care is to assist patients to remain in community living arrangements. Yet home care often fails to prevent hospitalizations and to facilitate discharges to community living, thus putting patients at risk of additional health challenges and increasing care costs. To determine the relationship between home health agency work environments and agency-level rates of acute hospitalization and discharges to community living. Analysis of linked Center for Medicare and Medicaid Services Home Health Compare data and nurse survey data from 118 home health agencies. Robust regression models were used to estimate the effect of work environment ratings on between-agency variation in rates of acute hospitalization and community discharge. Home health agencies with good work environments had lower rates of acute hospitalizations and higher rates of patient discharges to community living arrangements compared with home health agencies with poor work environments. Improved work environments in home health agencies hold promise for optimizing patient outcomes and reducing use of expensive hospital and institutional care.

Model Averaging for Predicting the Exposure to Aflatoxin B1 Using DNA Methylation in White Blood Cells of Infants

NASA Astrophysics Data System (ADS)

Rahardiantoro, S.; Sartono, B.; Kurnia, A.

2017-03-01

In recent years, DNA methylation has been the special issue to reveal the pattern of a lot of human diseases. Huge amount of data would be the inescapable phenomenon in this case. In addition, some researchers interesting to take some predictions based on these huge data, especially using regression analysis. The classical approach would be failed to take the task. Model averaging by Ando and Li [1] could be an alternative approach to face this problem. This research applied the model averaging to get the best prediction in high dimension of data. In the practice, the case study by Vargas et al [3], data of exposure to aflatoxin B1 (AFB1) and DNA methylation in white blood cells of infants in The Gambia, take the implementation of model averaging. The best ensemble model selected based on the minimum of MAPE, MAE, and MSE of predictions. The result is ensemble model by model averaging with number of predictors in model candidate is 15.

Analysis of Naval Facilities Engineering Command’s (NAVFAC) Contracting Processes Using the Contract Management Maturity Model (CMMM)

DTIC Science & Technology

2006-12-01

Antecedents and Consequences of Failed Governance : the Enron Example. Corporate Governance , 5: 5. Garrett, G., & Rendon, R. 2005(a). Contract Management... government organization because NAVFAC faces competition analogous to the corporate world. If NAVFAC fails to provide adequate services, the ...applicable to NAVFAC even though NAVFAC is a government organization because NAVFAC faces competition analogous to the corporate world. If NAVFAC fails to

Role of subdural electrocorticography in prediction of long-term seizure outcome in epilepsy surgery

PubMed Central

Juhász, Csaba; Shah, Aashit; Sood, Sandeep; Chugani, Harry T.

2009-01-01

Since prediction of long-term seizure outcome using preoperative diagnostic modalities remains suboptimal in epilepsy surgery, we evaluated whether interictal spike frequency measures obtained from extraoperative subdural electrocorticography (ECoG) recording could predict long-term seizure outcome. This study included 61 young patients (age 0.4–23.0 years), who underwent extraoperative ECoG recording prior to cortical resection for alleviation of uncontrolled focal seizures. Patient age, frequency of preoperative seizures, neuroimaging findings, ictal and interictal ECoG measures were preoperatively obtained. The seizure outcome was prospectively measured [follow-up period: 2.5–6.4 years (mean 4.6 years)]. Univariate and multivariate logistic regression analyses determined how well preoperative demographic and diagnostic measures predicted long-term seizure outcome. Following the initial cortical resection, Engel Class I, II, III and IV outcomes were noted in 35, 6, 12 and 7 patients, respectively. One child died due to disseminated intravascular coagulation associated with pseudomonas sepsis 2 days after surgery. Univariate regression analyses revealed that incomplete removal of seizure onset zone, higher interictal spike-frequency in the preserved cortex and incomplete removal of cortical abnormalities on neuroimaging were associated with a greater risk of failing to obtain Class I outcome. Multivariate logistic regression analysis revealed that incomplete removal of seizure onset zone was the only independent predictor of failure to obtain Class I outcome. The goodness of regression model fit and the predictive ability of regression model were greatest in the full regression model incorporating both ictal and interictal measures [R2 0.44; Area under the receiver operating characteristic (ROC) curve: 0.81], slightly smaller in the reduced model incorporating ictal but not interictal measures (R2 0.40; Area under the ROC curve: 0.79) and slightly smaller again in the reduced model incorporating interictal but not ictal measures (R2 0.27; Area under the ROC curve: 0.77). Seizure onset zone and interictal spike frequency measures on subdural ECoG recording may both be useful in predicting the long-term seizure outcome of epilepsy surgery. Yet, the additive clinical impact of interictal spike frequency measures to predict long-term surgical outcome may be modest in the presence of ictal ECoG and neuroimaging data. PMID:19286694

Water clustering in glassy polymers.

PubMed

Davis, Eric M; Elabd, Yossef A

2013-09-12

In this study, water solubility and water clustering in several glassy polymers, including poly(methyl methacrylate) (PMMA), poly(styrene) (PS), and poly(vinylpyrrolidone) (PVP), were measured using both quartz spring microbalance (QSM) and Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy. Specifically, QSM was used to determine water solubility, while FTIR-ATR spectroscopy provided a direct, molecular-level measurement of water clustering. The Flory-Huggins theory was employed to obtain a measure of water-polymer interaction and water solubility, through both prediction and regression, where the theory failed to predict water solubility in both PMMA and PVP. Furthermore, a comparison of water clustering between direct FTIR-ATR spectroscopy measurements and predictions from the Zimm-Lundberg clustering analysis produced contradictory results. The failure of the Flory-Huggins theory and Zimm-Lundberg clustering analysis to describe water solubility and water clustering, respectively, in these glassy polymers is in part due to the equilibrium constraints under which these models are derived in contrast to the nonequilibrium state of glassy polymers. Additionally, FTIR-ATR spectroscopy results were compared to temperature-dependent diffusivity data, where a correlation between the activation energy for diffusion and the measured water clustering was observed.

Sociodemographic predictors of elderly's psychological well-being in Malaysia.

PubMed

Momtaz, Yadollah A; Ibrahim, Rahimah; Hamid, Tengku A; Yahaya, Nurizan

2011-05-01

Psychological well-being as one of the most important indicators of successful aging has received substantial attention in the gerontological literature. Prior studies show that sociodemographic factors influencing elderly's psychological well-being are multiple and differ across cultures. The aim of this study was to identify significant sociodemographic predictors of psychological well-being among Malay elders. The study included 1415 older Malays (60-100 years, 722 women), randomly selected through a multistage stratified random method from Peninsular Malaysia. WHO-Five well-being index was used to measure psychological well-being. Data analysis was conducted using the Statistical Package for Social Sciences (SPSS) version 13.0. Using multiple regression analysis a significant model emerged (F(7, 1407) = 20.14, p ≤ 0.001), where age, sex, marital status, and household income were significant predictor variables of psychological well-being among Malay elders. However, level of education, employment status, and place of residence failed to predict psychological well-being. This study showed that the oldest old, elderly women, unmarried, and the poor elderly people are at risk for experiencing low psychological well-being. Therefore, they need special attention from family, policy makers, and those who work with elderly people.

Steep delay discounting and addictive behavior: a meta-analysis of continuous associations.

PubMed

Amlung, Michael; Vedelago, Lana; Acker, John; Balodis, Iris; MacKillop, James

2017-01-01

To synthesize continuous associations between delayed reward discounting (DRD) and both addiction severity and quantity-frequency (QF); to examine moderators of these relationships; and to investigate publication bias. Meta-analysis of published studies examining continuous associations between DRD and addictive behaviors. Published, peer-reviewed studies on addictive behaviors (alcohol, tobacco, cannabis, stimulants, opiates and gambling) were identified via PubMed, MEDLINE and PsycInfo. Studies were restricted to DRD measures of monetary gains. Random-effects meta-analysis was conducted using Pearson's r as the effect size. Publication bias was evaluated using fail-safe N, Begg-Mazumdar and Egger's tests, meta-regression of publication year and effect size and imputation of missing studies. The primary meta-analysis revealed a small magnitude effect size that was highly significant (r = 0.14, P < 10 -14 ). Significantly larger effect sizes were observed for studies examining severity compared with QF (P = 0.01), but not between the type of addictive behavior (P = 0.30) or DRD assessment (P = 0.90). Indices of publication bias suggested a modest impact of unpublished findings. Delayed reward discounting is associated robustly with continuous measures of addiction severity and quantity-frequency. This relation is generally robust across type of addictive behavior and delayed reward discounting assessment modality. © 2016 Society for the Study of Addiction.

Effects of youth, price, and audience size on alcohol advertising in magazines.

PubMed

Nelson, Jon P; Young, Douglas J

2008-04-01

In this paper, we study the effects of youth readership, price of advertisements, and audience size on alcohol advertising in 35 major magazines. The regressions also account for readership demographics (adult reader age, income, gender, race), magazine characteristics (newsstand sales, number of annual issues), and type of beverage (beer, wine, spirits). Using count data models, the results indicate significant effects for price, audience size, and adult demographics, but fail to support claims that alcohol advertisers target adolescent readers.

Prediction failure of a wolf landscape model

USGS Publications Warehouse

Mech, L.D.

2006-01-01

I compared 101 wolf (Canis lupus) pack territories formed in Wisconsin during 1993-2004 to the logistic regression predictive model of Mladenoff et al. (1995, 1997, 1999). Of these, 60% were located in putative habitat suitabilities 50% remained unoccupied by known packs after 24 years of recolonization. This model was a poor predictor of wolf re-colonizing locations in Wisconsin, apparently because it failed to consider the adaptability of wolves. Such models should be used cautiously in wolf-management or restoration plans.

Multivariate Analyses of Balance Test Performance, Vestibular Thresholds, and Age

PubMed Central

Karmali, Faisal; Bermúdez Rey, María Carolina; Clark, Torin K.; Wang, Wei; Merfeld, Daniel M.

2017-01-01

We previously published vestibular perceptual thresholds and performance in the Modified Romberg Test of Standing Balance in 105 healthy humans ranging from ages 18 to 80 (1). Self-motion thresholds in the dark included roll tilt about an earth-horizontal axis at 0.2 and 1 Hz, yaw rotation about an earth-vertical axis at 1 Hz, y-translation (interaural/lateral) at 1 Hz, and z-translation (vertical) at 1 Hz. In this study, we focus on multiple variable analyses not reported in the earlier study. Specifically, we investigate correlations (1) among the five thresholds measured and (2) between thresholds, age, and the chance of failing condition 4 of the balance test, which increases vestibular reliance by having subjects stand on foam with eyes closed. We found moderate correlations (0.30–0.51) between vestibular thresholds for different motions, both before and after using our published aging regression to remove age effects. We found that lower or higher thresholds across all threshold measures are an individual trait that account for about 60% of the variation in the population. This can be further distributed into two components with about 20% of the variation explained by aging and 40% of variation explained by a single principal component that includes similar contributions from all threshold measures. When only roll tilt 0.2 Hz thresholds and age were analyzed together, we found that the chance of failing condition 4 depends significantly on both (p = 0.006 and p = 0.013, respectively). An analysis incorporating more variables found that the chance of failing condition 4 depended significantly only on roll tilt 0.2 Hz thresholds (p = 0.046) and not age (p = 0.10), sex nor any of the other four threshold measures, suggesting that some of the age effect might be captured by the fact that vestibular thresholds increase with age. For example, at 60 years of age, the chance of failing is roughly 5% for the lowest roll tilt thresholds in our population, but this increases to 80% for the highest roll tilt thresholds. These findings demonstrate the importance of roll tilt vestibular cues for balance, even in individuals reporting no vestibular symptoms and with no evidence of vestibular dysfunction. PMID:29167656

Effectiveness of Non-nucleoside Reverse-Transcriptase Inhibitor-Based Antiretroviral Therapy in Women Previously Exposed to a Single Intrapartum Dose of Nevirapine: A Multi-country, Prospective Cohort Study

PubMed Central

Stringer, Jeffrey S. A.; McConnell, Michelle S.; Kiarie, James; Bolu, Omotayo; Anekthananon, Thanomsak; Jariyasethpong, Tavatchai; Potter, Dara; Mutsotso, Winnie; Borkowf, Craig B.; Mbori-Ngacha, Dorothy; Muiruri, Peter; Ong'ech, John Odero; Zulu, Isaac; Njobvu, Lungowe; Jetsawang, Bongkoch; Pathak, Sonal; Bulterys, Marc; Shaffer, Nathan; Weidle, Paul J.

2010-01-01

Background Intrapartum and neonatal single-dose nevirapine (NVP) reduces the risk of mother-to-child HIV transmission but also induces viral resistance to non-nucleoside reverse transcriptase inhibitor (NNRTI) drugs. This drug resistance largely fades over time. We hypothesized that women with a prior single-dose NVP exposure would have no more than a 10% higher cumulative prevalence of failure of their NNRTI-containing antiretroviral therapy (ART) over the first 48 wk of therapy than would women without a prior exposure. Methods and Findings We enrolled 355 NVP-exposed and 523 NVP-unexposed women at two sites in Zambia, one site in Kenya, and two sites in Thailand into a prospective, non-inferiority cohort study and followed them for 48 wk on ART. Those who died, discontinued NNRTI-containing ART, or had a plasma viral load ≥400 copies/ml at either the 24 wk or 48 wk study visits and confirmed on repeat testing were characterized as having failed therapy. Overall, 114 of 355 NVP-exposed women (32.1%) and 132 of 523 NVP-unexposed women (25.2%) met criteria for treatment failure. The difference in failure rates between the exposure groups was 6.9% (95% confidence interval [CI] 0.8%–13.0%). The failure rates of women stratified by our predefined exposure interval categories were as follows: 47 of 116 women in whom less than 6 mo elapsed between exposure and starting ART failed therapy (40%; p<0.001 compared to unexposed women); 25 of 67 women in whom 7–12 mo elapsed between exposure and starting ART failed therapy (37%; p = 0.04 compared to unexposed women); and 42 of 172 women in whom more than 12 mo elapsed between exposure and starting ART failed therapy (24%; p = 0.82 compared to unexposed women). Locally weighted regression analysis also indicated a clear inverse relationship between virologic failure and the exposure interval. Conclusions Prior exposure to single-dose NVP was associated with an increased risk of treatment failure; however, this risk seems largely confined to women with a more recent exposure. Women requiring ART within 12 mo of NVP exposure should not be prescribed an NNRTI-containing regimen as first-line therapy. Please see later in the article for the Editors' Summary PMID:20169113

Evaluating a grading change at UCSD school of medicine: pass/fail grading is associated with decreased performance on preclinical exams but unchanged performance on USMLE step 1 scores

PubMed Central

2014-01-01

Background To assess the impact of a change in preclerkship grading system from Honors/Pass/Fail (H/P/F) to Pass/Fail (P/F) on University of California, San Diego (UCSD) medical students’ academic performance. Methods Academic performance of students in the classes of 2011 and 2012 (constant-grading classes) were collected and compared with performance of students in the class of 2013 (grading-change class) because the grading policy at UCSD SOM was changed for the class of 2013, from H/P/F during the first year (MS1) to P/F during the second year (MS2). For all students, data consisted of test scores from required preclinical courses from MS1 and MS2 years, and USMLE Step 1 scores. Linear regression analysis controlled for other factors that could be predictive of student performance (i.e., MCAT scores, undergraduate GPA, age, gender, etc.) in order to isolate the effect of the changed grading policy on academic performance. The change in grading policy in the MS2 year only, without any corresponding changes to the medical curriculum, presents a unique natural experiment with which to cleanly evaluate the effect of P/F grading on performance outcomes. Results After controlling for other factors, the grading policy change to P/F grading in the MS2 year had a negative impact on second-year grades relative to first-year grades (the constant-grading classes performed 1.65% points lower during their MS2 year compared to the MS1 year versus 3.25% points lower for the grading-change class, p < 0.0001), but had no observable impact on USMLE Step 1 scores. Conclusions A change in grading from H/P/F grading to P/F grading was associated with decreased performance on preclinical examinations but no decrease in performance on the USMLE Step 1 examination. These results are discussed in the broader context of the multitude of factors that should be considered in assessing the merits of various grading systems, and ultimately the authors recommend the continuation of pass-fail grading at UCSD School of Medicine. PMID:24980918

Predictors of early graft failure after coronary artery bypass grafting for chronic total occlusion.

PubMed

Oshima, Hideki; Tokuda, Yoshiyuki; Araki, Yoshimori; Ishii, Hideki; Murohara, Toyoaki; Ozaki, Yukio; Usui, Akihiko

2016-07-01

Little is known regarding the transit-time flow measurement (TTFM) variables in grafts anastomosed to chronically totally occluded vessels (CTOs). We aimed to establish the TTFM cut-off values for detecting graft failure in bypass grafts anastomosed to chronically totally occluded arteries and clarify the relationship between early graft failure and the grade of collateral circulation/regional wall motion of the CTO territory. Among 491 patients who underwent isolated coronary artery bypass grafting (CABG) from 2009 to 2015, 196 cases with CTOs underwent postoperative coronary angiography within 1 month after CABG. Two hundred and forty-one CTOs in all patients were examined. Thirty-two CTOs (13%) were not bypassed and 214 conduits were anastomosed to CTOs and underwent intraoperative TTFM. Arterial conduits and saphenous vein grafts (SVGs) were used in 102 and 112 cases, respectively. Among the arterial conduit procedures that were performed, 78 involved the left internal thoracic artery (LITA), 10 involved the right internal thoracic artery (RITA) and 14 involved the right gastroepiploic artery (rGEA). Any graft showing Fitzgibbon type B or O lesions on angiography was considered to be a failing graft. The insufficiency rates for LITA, RITA, rGEA and SVG procedures were 5.1, 10, 14.3 and 7.1%, respectively. The TTFM variables recorded in failing grafts had a significantly lower mean flow (Qmean) and higher pulsatility index (PI) compared with patent grafts. Furthermore, akinetic or dyskinetic wall motion in the territory of bypassed CTOs was observed at a significantly higher rate in failing grafts. A multivariable regression analysis and receiver operating characteristic analysis revealed good predictors of early graft failure as follows: a Qmean value of < 11.5 ml/min for arterial conduits, a PI value of >5.85 and akinetic/dyskinetic wall motion in the CTO territory for SVGs. The Rentrop collateral grade was not associated with early graft failure. The Qmean value and PI value by the TTFM are useful to detect early graft failure in conduits anastomosed to CTOs. The collateral grade is not associated with graft failure; however, bypass grafting to CTOs with akinetic/dyskinetic wall motion should be carefully considered. © The Author 2016. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

On using summary statistics from an external calibration sample to correct for covariate measurement error.

PubMed

Guo, Ying; Little, Roderick J; McConnell, Daniel S

2012-01-01

Covariate measurement error is common in epidemiologic studies. Current methods for correcting measurement error with information from external calibration samples are insufficient to provide valid adjusted inferences. We consider the problem of estimating the regression of an outcome Y on covariates X and Z, where Y and Z are observed, X is unobserved, but a variable W that measures X with error is observed. Information about measurement error is provided in an external calibration sample where data on X and W (but not Y and Z) are recorded. We describe a method that uses summary statistics from the calibration sample to create multiple imputations of the missing values of X in the regression sample, so that the regression coefficients of Y on X and Z and associated standard errors can be estimated using simple multiple imputation combining rules, yielding valid statistical inferences under the assumption of a multivariate normal distribution. The proposed method is shown by simulation to provide better inferences than existing methods, namely the naive method, classical calibration, and regression calibration, particularly for correction for bias and achieving nominal confidence levels. We also illustrate our method with an example using linear regression to examine the relation between serum reproductive hormone concentrations and bone mineral density loss in midlife women in the Michigan Bone Health and Metabolism Study. Existing methods fail to adjust appropriately for bias due to measurement error in the regression setting, particularly when measurement error is substantial. The proposed method corrects this deficiency.

Medical students' personal experience of high-stakes failure: case studies using interpretative phenomenological analysis.

PubMed

Patel, R S; Tarrant, C; Bonas, S; Shaw, R L

2015-05-12

Failing a high-stakes assessment at medical school is a major event for those who go through the experience. Students who fail at medical school may be more likely to struggle in professional practice, therefore helping individuals overcome problems and respond appropriately is important. There is little understanding about what factors influence how individuals experience failure or make sense of the failing experience in remediation. The aim of this study was to investigate the complexity surrounding the failure experience from the student's perspective using interpretative phenomenological analysis (IPA). The accounts of three medical students who had failed final re-sit exams, were subjected to in-depth analysis using IPA methodology. IPA was used to analyse each transcript case-by-case allowing the researcher to make sense of the participant's subjective world. The analysis process allowed the complexity surrounding the failure to be highlighted, alongside a narrative describing how students made sense of the experience. The circumstances surrounding students as they approached assessment and experienced failure at finals were a complex interaction between academic problems, personal problems (specifically finance and relationships), strained relationships with friends, family or faculty, and various mental health problems. Each student experienced multi-dimensional issues, each with their own individual combination of problems, but experienced remediation as a one-dimensional intervention with focus only on improving performance in written exams. What these students needed to be included was help with clinical skills, plus social and emotional support. Fear of termination of the their course was a barrier to open communication with staff. These students' experience of failure was complex. The experience of remediation is influenced by the way in which students make sense of failing. Generic remediation programmes may fail to meet the needs of students for whom personal, social and mental health issues are a part of the picture.

Internal predictors of burnout in psychiatric nurses: An Indian study

PubMed Central

Chakraborty, Rudraprosad; Chatterjee, Arunima; Chaudhury, Suprakash

2012-01-01

Background: Research has not adequately focused on the issue of burnout in Psychiatric nurses, despite the fact that they suffer considerable stress in their work. Till date no study has been conducted on burnout among psychiatric nurses in India. Further, there is a particular lack of research in internal variables predicting burnout in them. Aims: To determine whether there are any internal psychological factors relevant to burnout in psychiatric nurses in India. Materials and Methods: We recruited 101 psychiatric nurses scoring less than two in General Health Questionnaire, version 12 (GHQ-12) from two psychiatric hospitals after obtaining informed consent. All subjects filled up a sociodemographic data sheet along with global adjustment scale, emotional maturity scale, PGI general well-being scale, locus of control scale, and Copenhagen burnout inventory (CBI). Correlations between burnout and sociodemographic/clinical variables were done by Pearson's r or Spearman's rho. Signi ficant variables were entered in a stepwise multiple linear regression analysis with total burnout score as dependent variable. Results: Age, duration of total period of nursing, prior military training, locus of control, sense of general well-being, adjustment capabilities, and emotional maturity had significant relation with burnout. Of them, emotional maturity was the most significant protective factors against burnout along with adjustment capabilities, sense of physical well-being, and military training in decreasing significance. Together they explained 41% variation in total burnout score which is significant at <0.001 level. An internal locus of control was inversely correlated with burnout, but failed to predict it in regression analysis. Conclusion: Emotional maturity, adjustability, sense of general physical well-being as well as prior military training significantly predicted lower burnout. Of them, emotional maturity was the most important predictor. Internal locus of control was also correlated with lower burnout. PMID:24250044

Effect of Morbid Obesity on Midurethral Sling Efficacy for the Management of Stress Urinary Incontinence.

PubMed

Elshatanoufy, Solafa; Matthews, Alexandra; Yousif, Mairy; Jamil, Marcus; Gutta, Sravanthi; Gill, Harmanjit; Galvin, Shelley L; Luck, Ali M

2018-05-04

The aim of our study was to assess midurethral sling (MUS) failure rate in the morbidly obese (body mass index [BMI] ≥40 kg/m) population as compared with normal-weight individuals. Our secondary objective was to assess the difference in complication rates. This is a retrospective cohort study. We included all patients who underwent a synthetic MUS procedure from January 1, 2008, to December 31, 2015, in our health system. Failure was defined as reported stress urinary incontinence symptoms or treatment for stress urinary incontinence. Variables collected were BMI; smoking status; comorbidities; perioperative (≤24 hours), short-term (≤30 days), and long-term (>30 days) complications; and follow-up time. Statistics include analysis of variance, χ test, logistic regression, Kaplan-Meier method, and Cox regression. There were 431 patients included in our analysis. Forty-nine patients were in class 3 with a BMI mean of 44.9 ± 5.07 kg/m. Median follow-up time was 52 months (range, 6-119 months). Class 3 obesity (BMI ≥40 kg/m) was the only group that had an increased risk of failure when compared with the normal-weight group (P = 0.03; odds ratio, 2.47; 95% confidence interval, 1.09-5.59). Obesity was not a significant predictor of perioperative, short-term, or long-term postoperative complications (P = 0.19, P = 0.28, and P = 0.089, respectively) after controlling for other comorbidities. Patients in the class 3 obesity group who are treated with an MUS are 2 times as likely to fail when compared with those in the normal-weight category on long-term follow-up with similar low complication rates.

How useful is determination of anti-factor Xa activity to guide bridging therapy with enoxaparin? A pilot study.

PubMed

Hammerstingl, Christoph; Omran, Heyder; Tripp, Christian; Poetzsch, Bernd

2009-02-01

Low-molecular-weight heparins (LMWH) are commonly used as peri-procedural bridging anticoagulants. The usefulness of measurement of anti-factor Xa activity (anti-Xa) to guide bridging therapy with LMWH is unknown. It was the objective of this study to determine levels of anti-Xa during standard bridging therapy with enoxaparin, and to examine predictors for residual anti-Xa. Consecutive patients receiving enoxaparin at a dosage of 1 mg/kg body weight/12 hours for temporary interruption of phenprocoumon were prospectively enrolled to the study. Blood-samples were obtained 14 hours after LMWH-application immediately pre- procedurally. Procedural details, clinical and demographic data were collected and subsequently analyzed. Seventy patients were included (age 75.2 +/- 10.8 years, Cr Cl 55.7 +/- 21.7ml/min, body mass index [BMI] 27.1 +/- 4.9). LMWH- therapy was for a mean of 4.2 +/- 1.6 days; overall anti-Xa was 0.58 +/- 0.32 U/ml. In 37 (52.8%) of patients anti-Xa was > or U/ml, including 10 (14.3%) patients with anti-Xa > 1U/ml. Linear regression analysis of single variables and logistic multivariable regression analysis failed to prove a correlation between anti-Xa and single or combined factors. No major bleeding, no thromboembolism and four (5.7%) minor haemorrhages were observed. When bridging OAC with therapeutic doses of enoxaparin a high percentage of patients undergo interventions with high residual anti-Xa. The levels of anti-Xa vary largely and are independent of single or combined clinical variables. Since the anti-Xa-related outcome of patients receiving bridging therapy with LMWH is not investigated, no firm recommendation on the usefulness of monitoring of anti-Xa can be given at this stage.

Comparative Effectiveness of Blood Pressure-lowering Drugs in Patients who have Already Suffered From Stroke

PubMed Central

Wang, Wei-Ting; You, Li-Kai; Chiang, Chern-En; Sung, Shih-Hsien; Chuang, Shao-Yuan; Cheng, Hao-Min; Chen, Chen-Huan

2016-01-01

Abstract Hypertension is the most important risk factor for stroke and stroke recurrence. However, the preferred blood pressure (BP)-lowering drug class for patients who have suffered from a stroke has yet to be determined. To investigate the relative effects of BP-lowering therapies [angiotensin-converting enzyme inhibitor (ACEI), angiotensin receptor blockers (ARB), β blockers, calcium channel blockers (CCBs), diuretics, and combinations of these drugs] in patients with a prior stroke history, we performed a systematic review and meta-analysis using both traditional frequentist and Bayesian random-effects models and meta-regression of randomized controlled trials (RCTs) on the outcomes of recurrent stroke, coronary heart disease (CHD), and any major adverse cardiac and cerebrovascular events (MACCE). Trials were identified from searches of published hypertension guidelines, electronic databases, and previous systematic reviews. Fifteen RCTs composed of 39,329 participants with previous stroke were identified. Compared with the placebo, only ACEI along with diuretics significantly reduced recurrent stroke events [odds ratio (OR) = 0.54, 95% credibility interval (95% CI) 0.33–0.90]. On the basis of the distribution of posterior probabilities, the treatment ranking consistently identified ACEI along with diuretics as the preferred BP-lowering strategy for the reduction of recurrent stroke and CHD (31% and 35%, respectively). For preventing MACCE, diuretics appeared to be the preferred agent for stroke survivors (34%). Moreover, the meta-regression analysis failed to demonstrate a statistical significance between BP reduction and all outcomes (P = 0.1618 for total stroke, 0.4933 for CHD, and 0.2411 for MACCE). Evidence from RCTs supports the use of diuretics-based treatment, especially when combined with ACEI, for the secondary prevention of recurrent stroke and any vascular events in patients who have suffered from stroke. PMID:27082571

Educational attainment has a limited impact on disease management outcomes in heart failure.

PubMed

Smith, Brad; Forkner, Emma; Krasuski, Richard A; Galbreath, Autumn Dawn; Freeman, Gregory L

2006-06-01

The objective of this study was to assess whether educational attainment moderates outcomes in the intervention group in a trial of disease management in heart failure (HF). Data were collected from a sample of 654 patients enrolled in the disease management arm of a community- based study of HF patients. The full sample was used to analyze two primary outcomes- all-cause mortality and cardiac event-free survival. Two other primary outcomes- rates of HF-related emergency department (ED) visits and inpatient admissions-and secondary outcomes (patient self-confidence in managing HF symptoms and daily dietary sodium intake in milligrams) were analyzed in a smaller sample of 602 patients who completed at least 6 months of disease management. One-way analysis of variance and chi (2) tests were used to assess differences in baseline demographic and clinical characteristics. Survival analyses were conducted with proportional hazards regression, while negative binomial regression was used to assess educational differences in ED usage and inpatient admissions. Repeated measures analysis of variance models were used to assess whether secondary outcomes differed across educational strata and/or over time. All outcome analyses were adjusted for confounders. Patients with the least education fared the poorest for all-cause mortality, but education- related differences failed to achieve statistical significance. No education-related differences were observed for cardiac event-free survival, or for the rates of inpatient admission and ED usage. For secondary outcomes, sodium intake differed significantly by education (p = 0.04), with the largest drop (-838 mg/day) observed in the least well-educated group. Confidence increased an approximately equal amount (2.1-3.0 points on a 100-point scale) across all educational strata (p = ns). Low educational attainment may not be a barrier to effective disease management.

Internal predictors of burnout in psychiatric nurses: An Indian study.

PubMed

Chakraborty, Rudraprosad; Chatterjee, Arunima; Chaudhury, Suprakash

2012-07-01

Research has not adequately focused on the issue of burnout in Psychiatric nurses, despite the fact that they suffer considerable stress in their work. Till date no study has been conducted on burnout among psychiatric nurses in India. Further, there is a particular lack of research in internal variables predicting burnout in them. To determine whether there are any internal psychological factors relevant to burnout in psychiatric nurses in India. We recruited 101 psychiatric nurses scoring less than two in General Health Questionnaire, version 12 (GHQ-12) from two psychiatric hospitals after obtaining informed consent. All subjects filled up a sociodemographic data sheet along with global adjustment scale, emotional maturity scale, PGI general well-being scale, locus of control scale, and Copenhagen burnout inventory (CBI). Correlations between burnout and sociodemographic/clinical variables were done by Pearson's r or Spearman's rho. Signi ficant variables were entered in a stepwise multiple linear regression analysis with total burnout score as dependent variable. Age, duration of total period of nursing, prior military training, locus of control, sense of general well-being, adjustment capabilities, and emotional maturity had significant relation with burnout. Of them, emotional maturity was the most significant protective factors against burnout along with adjustment capabilities, sense of physical well-being, and military training in decreasing significance. Together they explained 41% variation in total burnout score which is significant at <0.001 level. An internal locus of control was inversely correlated with burnout, but failed to predict it in regression analysis. Emotional maturity, adjustability, sense of general physical well-being as well as prior military training significantly predicted lower burnout. Of them, emotional maturity was the most important predictor. Internal locus of control was also correlated with lower burnout.

Lowering generic drug prices: less regulation equals more competition.

PubMed

Anis, Aslam H; Guh, Daphne P; Woolcott, John

2003-01-01

In Ontario, Canada, the 70/90 regulations were instituted in May 1993 to establish provincial government procurement prices for generic drugs. Accordingly, the first generic entrant's price could not exceed 70% of the incumbent's branded price. Subsequent entrants' prices could not exceed 90% of the first entrant's price. These regulations' impact on generic market competitiveness are evaluated. Data on 518 drugs spanning nine therapeutic classifications were collected for the period of 04/01/1987 to 12/31/1998 from Ontario Drug Benefit formulary and IMS Canada. The period 04/01/1987 to 04/30/1993 was defined as the before period (BP) and 05/01/1993 to 12/31/1998 was the after period (AP). We compared the price ratio (P = P(G)/P(B) ) between BP and AP and performed regression analysis to assess the determinants of P. in both the BP and AP decreased as the number of generic firms increased within these periods. However, this decrease in was significantly less in the AP (median: 0.75 --> 0.68 --> 0.67) than in BP (0.71 --> 0.61 --> 0.53) as the number of generics increased from 1 to 2 to 3, respectively. The regression analysis showed that the price ratio in the AP was higher than that in the BP by 0.05, 0.09, and 0.13 for first, second, and third generic entrant respectively. Our findings show that the 70/90 regulations not only failed to achieve their goal of lowering the procurement price but instead the opposite occurred. The mandated procurement price became a focal point and resulted in a clustering of prices around the maximum allowable levels with little price dispersion.

Malignant Lymphatic and Hematopoietic Neoplasms Mortality in Serbia, 1991–2010: A Joinpoint Regression Analysis

PubMed Central

Ilic, Milena; Ilic, Irena

2014-01-01

Background Limited data on mortality from malignant lymphatic and hematopoietic neoplasms have been published for Serbia. Methods The study covered population of Serbia during the 1991–2010 period. Mortality trends were assessed using the joinpoint regression analysis. Results Trend for overall death rates from malignant lymphoid and haematopoietic neoplasms significantly decreased: by −2.16% per year from 1991 through 1998, and then significantly increased by +2.20% per year for the 1998–2010 period. The growth during the entire period was on average +0.8% per year (95% CI 0.3 to 1.3). Mortality was higher among males than among females in all age groups. According to the comparability test, mortality trends from malignant lymphoid and haematopoietic neoplasms in men and women were parallel (final selected model failed to reject parallelism, P = 0.232). Among younger Serbian population (0–44 years old) in both sexes: trends significantly declined in males for the entire period, while in females 15–44 years of age mortality rates significantly declined only from 2003 onwards. Mortality trend significantly increased in elderly in both genders (by +1.7% in males and +1.5% in females in the 60–69 age group, and +3.8% in males and +3.6% in females in the 70+ age group). According to the comparability test, mortality trend for Hodgkin's lymphoma differed significantly from mortality trends for all other types of malignant lymphoid and haematopoietic neoplasms (P<0.05). Conclusion Unfavourable mortality trend in Serbia requires targeted intervention for risk factors control, early diagnosis and modern therapy. PMID:25333862

Does higher body mass index contribute to worse asthma control in an urban population?

PubMed Central

Clerisme-Beaty, Emmanuelle M; Karam, Sabine; Rand, Cynthia; Patino, Cecilia M; Bilderback, Andrew; Riekert, Kristin A; Okelo, Sande O.; Diette, Gregory B.

2009-01-01

Background Epidemiologic findings support a positive association between asthma and obesity. Objective Determine whether obesity or increasing level of body mass index (BMI) are associated with worse asthma control in an ethnically diverse urban population. Methods Cross sectional assessment of asthma control was done in asthmatics recruited from primary care offices using four different validated asthma control questionnaires: the Asthma Control and Communication Instrument (ACCI), the Asthma Control Test (ACT), the Asthma Control Questionnaire (ACQ) and the Asthma Therapy Assessment Questionnaire (ATAQ). Multiple linear regression analysis was performed to evaluate the association between obesity and increasing BMI level and asthma control. Results Of 292 subjects mean age of 47 years, the majority were women (82%) and African American (67%). There was a high prevalence of obesity with 63%, with only 15% being normal weight. The mean score from all four questionnaires showed an average sub-optimal asthma control (mean score/maximum possible score): ACCI (8.3/19), ACT (15.4/ 25), ACQ (2.1/ 6), and ATAQ (1.3/ 4). Regression analysis showed no association between obesity or increasing BMI level and asthma control using all four questionnaires. This finding persisted even after adjusting for FEV1, smoking status, race, gender, selected co-morbid illnesses, and long-term asthma controller use. Conclusion Using four validated asthma control questionnaires, we failed to find an association between obesity and asthma control in an urban population with asthma. Weight loss may not be an appropriate strategy to improve asthma control in this population. Capsule Summary Using four different validated asthma control measures, there was no association between obesity or increasing body mass index and asthma control in a largely obese urban outpatient minority population. PMID:19615731

Why fish oil fails: a comprehensive 21st century lipids-based physiologic analysis.

PubMed

Peskin, B S

2014-01-01

The medical community suffered three significant fish oil failures/setbacks in 2013. Claims that fish oil's EPA/DHA would stop the progression of heart disease were crushed when The Risk and Prevention Study Collaborative Group (Italy) released a conclusive negative finding regarding fish oil for those patients with high risk factors but no previous myocardial infarction. Fish oil failed in all measures of CVD prevention-both primary and secondary. Another major 2013 setback occurred when fish oil's DHA was shown to significantly increase prostate cancer in men, in particular, high-grade prostate cancer, in the Selenium and Vitamin E Cancer Prevention Trial (SELECT) analysis by Brasky et al. Another monumental failure occurred in 2013 whereby fish oil's EPA/DHA failed to improve macular degeneration. In 2010, fish oil's EPA/DHA failed to help Alzheimer's victims, even those with low DHA levels. These are by no means isolated failures. The promise of fish oil and its so-called active ingredients EPA / DHA fails time and time again in clinical trials. This lipids-based physiologic review will explain precisely why there should have never been expectation for success. This review will focus on underpublicized lipid science with a focus on physiology.

Why Fish Oil Fails: A Comprehensive 21st Century Lipids-Based Physiologic Analysis

PubMed Central

Peskin, B. S.

2014-01-01

The medical community suffered three significant fish oil failures/setbacks in 2013. Claims that fish oil's EPA/DHA would stop the progression of heart disease were crushed when The Risk and Prevention Study Collaborative Group (Italy) released a conclusive negative finding regarding fish oil for those patients with high risk factors but no previous myocardial infarction. Fish oil failed in all measures of CVD prevention—both primary and secondary. Another major 2013 setback occurred when fish oil's DHA was shown to significantly increase prostate cancer in men, in particular, high-grade prostate cancer, in the Selenium and Vitamin E Cancer Prevention Trial (SELECT) analysis by Brasky et al. Another monumental failure occurred in 2013 whereby fish oil's EPA/DHA failed to improve macular degeneration. In 2010, fish oil's EPA/DHA failed to help Alzheimer's victims, even those with low DHA levels. These are by no means isolated failures. The promise of fish oil and its so-called active ingredients EPA / DHA fails time and time again in clinical trials. This lipids-based physiologic review will explain precisely why there should have never been expectation for success. This review will focus on underpublicized lipid science with a focus on physiology. PMID:24551453

The use of segmented regression in analysing interrupted time series studies: an example in pre-hospital ambulance care.

PubMed

Taljaard, Monica; McKenzie, Joanne E; Ramsay, Craig R; Grimshaw, Jeremy M

2014-06-19

An interrupted time series design is a powerful quasi-experimental approach for evaluating effects of interventions introduced at a specific point in time. To utilize the strength of this design, a modification to standard regression analysis, such as segmented regression, is required. In segmented regression analysis, the change in intercept and/or slope from pre- to post-intervention is estimated and used to test causal hypotheses about the intervention. We illustrate segmented regression using data from a previously published study that evaluated the effectiveness of a collaborative intervention to improve quality in pre-hospital ambulance care for acute myocardial infarction (AMI) and stroke. In the original analysis, a standard regression model was used with time as a continuous variable. We contrast the results from this standard regression analysis with those from segmented regression analysis. We discuss the limitations of the former and advantages of the latter, as well as the challenges of using segmented regression in analysing complex quality improvement interventions. Based on the estimated change in intercept and slope from pre- to post-intervention using segmented regression, we found insufficient evidence of a statistically significant effect on quality of care for stroke, although potential clinically important effects for AMI cannot be ruled out. Segmented regression analysis is the recommended approach for analysing data from an interrupted time series study. Several modifications to the basic segmented regression analysis approach are available to deal with challenges arising in the evaluation of complex quality improvement interventions.

Standardized Regression Coefficients as Indices of Effect Sizes in Meta-Analysis

ERIC Educational Resources Information Center

Kim, Rae Seon

2011-01-01

When conducting a meta-analysis, it is common to find many collected studies that report regression analyses, because multiple regression analysis is widely used in many fields. Meta-analysis uses effect sizes drawn from individual studies as a means of synthesizing a collection of results. However, indices of effect size from regression analyses…

Neural net controlled tag gas sampling system for nuclear reactors

DOEpatents

Gross, K.C.; Laug, M.T.; Lambert, J.B.; Herzog, J.P.

1997-02-11

A method and system are disclosed for providing a tag gas identifier to a nuclear fuel rod and analyze escaped tag gas to identify a particular failed nuclear fuel rod. The method and system include disposing a unique tag gas composition into a plenum of a nuclear fuel rod, monitoring gamma ray activity, analyzing gamma ray signals to assess whether a nuclear fuel rod has failed and is emitting tag gas, activating a tag gas sampling and analysis system upon sensing tag gas emission from a failed nuclear rod and evaluating the escaped tag gas to identify the particular failed nuclear fuel rod. 12 figs.

SVAw - a web-based application tool for automated surrogate variable analysis of gene expression studies

PubMed Central

2013-01-01

Background Surrogate variable analysis (SVA) is a powerful method to identify, estimate, and utilize the components of gene expression heterogeneity due to unknown and/or unmeasured technical, genetic, environmental, or demographic factors. These sources of heterogeneity are common in gene expression studies, and failing to incorporate them into the analysis can obscure results. Using SVA increases the biological accuracy and reproducibility of gene expression studies by identifying these sources of heterogeneity and correctly accounting for them in the analysis. Results Here we have developed a web application called SVAw (Surrogate variable analysis Web app) that provides a user friendly interface for SVA analyses of genome-wide expression studies. The software has been developed based on open source bioconductor SVA package. In our software, we have extended the SVA program functionality in three aspects: (i) the SVAw performs a fully automated and user friendly analysis workflow; (ii) It calculates probe/gene Statistics for both pre and post SVA analysis and provides a table of results for the regression of gene expression on the primary variable of interest before and after correcting for surrogate variables; and (iii) it generates a comprehensive report file, including graphical comparison of the outcome for the user. Conclusions SVAw is a web server freely accessible solution for the surrogate variant analysis of high-throughput datasets and facilitates removing all unwanted and unknown sources of variation. It is freely available for use at http://psychiatry.igm.jhmi.edu/sva. The executable packages for both web and standalone application and the instruction for installation can be downloaded from our web site. PMID:23497726

Setting and validating the pass/fail score for the NBDHE.

PubMed

Tsai, Tsung-Hsun; Dixon, Barbara Leatherman

2013-04-01

This report describes the overall process used for setting the pass/fail score for the National Board Dental Hygiene Examination (NBDHE). The Objective Standard Setting (OSS) method was used for setting the pass/fail score for the NBDHE. The OSS method requires a panel of experts to determine the criterion items and proportion of these items that minimally competent candidates would answer correctly, the percentage of mastery and the confidence level of the error band. A panel of 11 experts was selected by the Joint Commission on National Dental Examinations (Joint Commission). Panel members represented geographic distribution across the U.S. and had the following characteristics: full-time dental hygiene practitioners with experience in areas of preventive, periodontal, geriatric and special needs care, and full-time dental hygiene educators with experience in areas of scientific basis for dental hygiene practice, provision of clinical dental hygiene services and community health/research principles. Utilizing the expert panel's judgments, the pass/fail score was set and then the score scale was established using the Rasch measurement model. Statistical and psychometric analysis shows the actual failure rate and the OSS failure rate are reasonably consistent (2.4% vs. 2.8%). The analysis also showed the lowest error of measurement, an index of the precision at the pass/fail score point and that the highest reliability (0.97) are achieved at the pass/fail score point. The pass/fail score is a valid guide for making decisions about candidates for dental hygiene licensure. This new standard was reviewed and approved by the Joint Commission and was implemented beginning in 2011.

Risk factors for failed conversion of labor epidural analgesia to cesarean delivery anesthesia: a systematic review and meta-analysis of observational trials.

PubMed

Bauer, M E; Kountanis, J A; Tsen, L C; Greenfield, M L; Mhyre, J M

2012-10-01

This systematic review and meta-analysis evaluates evidence for seven risk factors associated with failed conversion of labor epidural analgesia to cesarean delivery anesthesia. Online scientific literature databases were searched using a strategy which identified observational trials, published between January 1979 and May 2011, which evaluated risk factors for failed conversion of epidural analgesia to anesthesia or documented a failure rate resulting in general anesthesia. 1450 trials were screened, and 13 trials were included for review (n=8628). Three factors increase the risk for failed conversion: an increasing number of clinician-administered boluses during labor (OR=3.2, 95% CI 1.8-5.5), greater urgency for cesarean delivery (OR=40.4, 95% CI 8.8-186), and a non-obstetric anesthesiologist providing care (OR=4.6, 95% CI 1.8-11.5). Insufficient evidence is available to support combined spinal-epidural versus standard epidural techniques, duration of epidural analgesia, cervical dilation at the time of epidural placement, and body mass index or weight as risk factors for failed epidural conversion. The risk of failed conversion of labor epidural analgesia to anesthesia is increased with an increasing number of boluses administered during labor, an enhanced urgency for cesarean delivery, and care being provided by a non-obstetric anesthesiologist. Further high-quality studies are needed to evaluate the many potential risk factors associated with failed conversion of labor epidural analgesia to anesthesia for cesarean delivery. Copyright © 2012 Elsevier Ltd. All rights reserved.

A Potent and Highly Efficacious Bcl-2/Bcl-xL Inhibitor

PubMed Central

McEachern, Donna; Yang, Chao-Yie; Meagher, Jennifer; Stuckey, Jeanne; Wang, Shaomeng

2013-01-01

Our previously reported Bcl-2/Bcl-xL inhibitor, 4, effectively inhibited tumor growth but failed to achieve complete regression in vivo. We have now performed extensive modifications on its pyrrole core structure, which has culminated in the discovery of 32 (BM-1074). Compound 32 binds to Bcl-2 and Bcl-xL proteins with Ki values of < 1 nM and inhibits cancer cell growth with IC50 values of 1-2 nM in four small-cell lung cancer cell lines sensitive to potent and specific Bcl-2/Bcl-xL inhibitors. Compound 32 is capable of achieving rapid, complete and durable tumor regression in vivo at a well-tolerated dose-schedule. Compound 32 is the most potent and efficacious Bcl-2/Bcl-xL inhibitor reported to date. PMID:23448298

Gesture and intonation are “sister systems” of infant communication: Evidence from regression patterns of language development

PubMed Central

Snow, David P.

2016-01-01

This study investigates infants’ transition from nonverbal to verbal communication using evidence from regression patterns. As an example of regressions, prelinguistic infants learning American Sign Language (ASL) use pointing gestures to communicate. At the onset of single signs, however, these gestures disappear. Petitto (1987) attributed the regression to the children’s discovery that pointing has two functions, namely, deixis and linguistic pronouns. The 1:2 relation (1 form, 2 functions) violates the simple 1:1 pattern that infants are believed to expect. This kind of conflict, Petitto argued, explains the regression. Based on the additional observation that the regression coincided with the boundary between prelinguistic and linguistic communication, Petitto concluded that the prelinguistic and linguistic periods are autonomous. The purpose of the present study was to evaluate the 1:1 model and to determine whether it explains a previously reported regression of intonation in English. Background research showed that gestures and intonation have different forms but the same pragmatic meanings, a 2:1 form-function pattern that plausibly precipitates the regression. The hypothesis of the study was that gestures and intonation are closely related. Moreover, because gestures and intonation change in the opposite direction, the negative correlation between them indicates a robust inverse relationship. To test this prediction, speech samples of 29 infants (8 to 16 months) were analyzed acoustically and compared to parent-report data on several verbal and gestural scales. In support of the hypothesis, gestures alone were inversely correlated with intonation. In addition, the regression model explains nonlinearities stemming from different form-function configurations. However, the results failed to support the claim that regressions linked to early words or signs reflect autonomy. The discussion ends with a focus on the special role of intonation in children’s transition from “prelinguistic” communication to language. PMID:28729753

Using Dominance Analysis to Determine Predictor Importance in Logistic Regression

ERIC Educational Resources Information Center

Azen, Razia; Traxel, Nicole

2009-01-01

This article proposes an extension of dominance analysis that allows researchers to determine the relative importance of predictors in logistic regression models. Criteria for choosing logistic regression R[superscript 2] analogues were determined and measures were selected that can be used to perform dominance analysis in logistic regression. A…

Predicting Student Success using Analytics in Course Learning Management Systems

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

Olama, Mohammed M; Thakur, Gautam; McNair, Wade

Educational data analytics is an emerging discipline, concerned with developing methods for exploring the unique types of data that come from the educational context. For example, predicting college student performance is crucial for both the student and educational institutions. It can support timely intervention to prevent students from failing a course, increasing efficacy of advising functions, and improving course completion rate. In this paper, we present the efforts carried out at Oak Ridge National Laboratory (ORNL) toward conducting predictive analytics to academic data collected from 2009 through 2013 and available in one of the most commonly used learning management systems,more » called Moodle. First, we have identified the data features useful for predicting student outcomes such as students scores in homework assignments, quizzes, exams, in addition to their activities in discussion forums and their total GPA at the same term they enrolled in the course. Then, Logistic Regression and Neural Network predictive models are used to identify students as early as possible that are in danger of failing the course they are currently enrolled in. These models compute the likelihood of any given student failing (or passing) the current course. Numerical results are presented to evaluate and compare the performance of the developed models and their predictive accuracy.« less

Predicting student success using analytics in course learning management systems

NASA Astrophysics Data System (ADS)

Olama, Mohammed M.; Thakur, Gautam; McNair, Allen W.; Sukumar, Sreenivas R.

2014-05-01

Educational data analytics is an emerging discipline, concerned with developing methods for exploring the unique types of data that come from the educational context. For example, predicting college student performance is crucial for both the student and educational institutions. It can support timely intervention to prevent students from failing a course, increasing efficacy of advising functions, and improving course completion rate. In this paper, we present the efforts carried out at Oak Ridge National Laboratory (ORNL) toward conducting predictive analytics to academic data collected from 2009 through 2013 and available in one of the most commonly used learning management systems, called Moodle. First, we have identified the data features useful for predicting student outcomes such as students' scores in homework assignments, quizzes, exams, in addition to their activities in discussion forums and their total GPA at the same term they enrolled in the course. Then, Logistic Regression and Neural Network predictive models are used to identify students as early as possible that are in danger of failing the course they are currently enrolled in. These models compute the likelihood of any given student failing (or passing) the current course. Numerical results are presented to evaluate and compare the performance of the developed models and their predictive accuracy.

National intelligence estimates and the Failed State Index.

PubMed

Voracek, Martin

2013-10-01

Across 177 countries around the world, the Failed State Index, a measure of state vulnerability, was reliably negatively associated with the estimates of national intelligence. Psychometric analysis of the Failed State Index, compounded of 12 social, economic, and political indicators, suggested factorial unidimensionality of this index. The observed correspondence of higher national intelligence figures to lower state vulnerability might arise through these two macro-level variables possibly being proxies of even more pervasive historical and societal background variables that affect both.

Cooperative Genome-Wide Analysis Shows Increased Homozygosity in Early Onset Parkinson's Disease

PubMed Central

Nalls, Michael A.; Martinez, Maria; Schulte, Claudia; Holmans, Peter; Gasser, Thomas; Hardy, John; Singleton, Andrew B.; Wood, Nicholas W.; Brice, Alexis; Heutink, Peter; Williams, Nigel; Morris, Huw R.

2012-01-01

Parkinson's disease (PD) occurs in both familial and sporadic forms, and both monogenic and complex genetic factors have been identified. Early onset PD (EOPD) is particularly associated with autosomal recessive (AR) mutations, and three genes, PARK2, PARK7 and PINK1, have been found to carry mutations leading to AR disease. Since mutations in these genes account for less than 10% of EOPD patients, we hypothesized that further recessive genetic factors are involved in this disorder, which may appear in extended runs of homozygosity. We carried out genome wide SNP genotyping to look for extended runs of homozygosity (ROHs) in 1,445 EOPD cases and 6,987 controls. Logistic regression analyses showed an increased level of genomic homozygosity in EOPD cases compared to controls. These differences are larger for ROH of 9 Mb and above, where there is a more than three-fold increase in the proportion of cases carrying a ROH. These differences are not explained by occult recessive mutations at existing loci. Controlling for genome wide homozygosity in logistic regression analyses increased the differences between cases and controls, indicating that in EOPD cases ROHs do not simply relate to genome wide measures of inbreeding. Homozygosity at a locus on chromosome19p13.3 was identified as being more common in EOPD cases as compared to controls. Sequencing analysis of genes and predicted transcripts within this locus failed to identify a novel mutation causing EOPD in our cohort. There is an increased rate of genome wide homozygosity in EOPD, as measured by an increase in ROHs. These ROHs are a signature of inbreeding and do not necessarily harbour disease-causing genetic variants. Although there might be other regions of interest apart from chromosome 19p13.3, we lack the power to detect them with this analysis. PMID:22427796

α-Fetoprotein is a surrogate marker for predicting treatment failure in telaprevir-based triple combination therapy for genotype 1b chronic hepatitis C Japanese patients with the IL28B minor genotype.

PubMed

Shimada, Noritomo; Tsubota, Akihito; Atsukawa, Masanori; Abe, Hiroshi; Ika, Makiko; Kato, Keizo; Sato, Yoshiyuki; Kondo, Chisa; Sakamoto, Choitsu; Tanaka, Yasuhito; Aizawa, Yoshio

2014-03-01

Even when treated with telaprevir-based triple therapy, some patients fail to achieve a sustained virological response. This study identified factors related closely to treatment failure. A total of 146 Japanese genotype 1b chronic hepatitis C patients were enrolled in this prospective, multicenter study and received a 24-week regimen of triple therapy. The end-of-treatment response rate was significantly lower in patients with the interleukin 28B (IL28B) (rs8099917) non-TT genotype (85.2%) than in those with the TT genotype (100%, P = 0.0002). Multiple logistic regression analysis identified high α-fetoprotein levels as an independent factor related to non-end-of-treatment response in patients with the non-TT genotype. A cut-off value of 20 ng/ml was determined for a non-end-of-treatment response; sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were 75.0%, 95.7%, 75.0%, 75.0%, and 92.6%, respectively. Multiple logistic regression analysis for a sustained virological response identified the IL28B TT genotype, low α-fetoprotein levels, non-responders, and a rapid virological response. The sustained virological response rate was significantly lower in patients with the non-TT genotype (59.3%) than in those with the TT genotype (96.7%, P < 0.0001). In patients with the non-TT genotype, α-fetoprotein was the most significant predictor for non-sustained virological response by univariate analysis. A cut-off value of 7.4 ng/ml α-fetoprotein was determined for non-sustained virological response; sensitivity, specificity, PPV, NPV, and accuracy were 63.6%, 87.5%, 77.8%, 77.8%, and 77.8%, respectively. For the non-TT patients, serum α-fetoprotein levels may be a surrogate marker for predicting treatment failure in telaprevir-based therapy for genotype 1b chronic hepatitis C. © 2013 Wiley Periodicals, Inc.

Do biomass fuel use and consumption of unsafe water mediate educational inequalities in stillbirth risk? An analysis of the 2007 Ghana Maternal Health Survey.

PubMed

Amegah, A Kofi; Näyhä, Simo; Jaakkola, Jouni J K

2017-02-07

Numerous studies have explored the association between educational inequalities and stillbirth but most have failed to elaborate how low educational attainment leads to an increased risk of stillbirth. We hypothesised that use of biomass fuels and consumption of unsafe water related to low educational attainment could explain the stillbirth burden in Ghana attributable to socioeconomic disadvantage. Data from the 2007 Ghana Maternal Health Survey, a nationally representative population-based survey were analysed for this study. Of the10 370 women aged 15-49 years interviewed via structured questionnaires for the survey, 7183 primiparous and multiparous women qualified for inclusion in the present study. In a logistic regression analysis that adjusted for age, area of residence, marital status and ethnicity of women, lower maternal primary education was associated with a 62% (OR=1.62; 95% CI 1.04 to 2.52) increased lifetime risk of stillbirth. Biomass fuel use and consumption of unsafe water mediated 18% and 8% of the observed effects, respectively. Jointly these two exposures explained 24% of the observed effects. The generalised additive modelling revealed a very flat inverted spoon-shaped smoothed curve which peaked at low levels of schooling (2-3 years) and confirms the findings from the logistic regression analysis. Our results show that biomass fuel use and unsafe water consumption could be important pathways through which low maternal educational attainment leads to stillbirths in Ghana and similar developing countries. Addressing educational inequalities in developing countries is thus essential for ensuring household choices that curtail environmental exposures and help improve pregnancy outcomes. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

'I Beg Your Pardon?': The Preverbal Negotiation of Failed Messages.

ERIC Educational Resources Information Center

Golinkoff, Roberta Michnick

1986-01-01

Analysis of videotapes recorded of three preverbal infants' communication attempts with their mothers revealed three behaviors: Negotiations occurred when mothers helped infants make their intents clear; Immediate Successes occurred when mothers readily comprehended the infants' intents; and Missed Attempts occurred when the mother failed to…

Measuring the impact of energy consumption and air quality indicators on climate change: evidence from the panel of UNFCC classified countries.

PubMed

Ozturk, Ilhan

2015-10-01

This study examines the relationship between energy consumption, air pollution, and climate change in the panel of six economically diversified countries classified by the United Nations Framework Convention on Climate Change (UNFCC) as industrialized countries and economies in transition nations by using the panel econometric techniques for the period of 1990-2012. The results of pooled least square regression show that both the energy consumption and air quality indicators have a positive and significant relationship with the climate change, i.e., 1 % increase in energy consumption increases greenhouse gas emissions by 0.124 %, carbon dioxide emissions increase by 0.652 %, methane emissions increase by 0.123 %, and nitrous oxide emissions increase greenhouse gas emissions by 0.105 % age points. The results of fixed-effect regression and random-effect regression confirmed the deteriorating impact of air quality indicators on climate change; however, the results failed to show any significant association between energy consumption and climate change when absorbing country-specific shocks and time-variant shocks during the study time period.

Sexually Dimorphic Expression of Secreted Frizzled-Related (SFRP) Genes in the Developing Mouse Müllerian Duct

PubMed Central

COX, SAM; SMITH, LEE; BOGANI, DEBORA; CHEESEMAN, MICHAEL; SIGGERS, PAM; GREENFIELD, ANDY

2007-01-01

In developing male embryos, the female reproductive tract primordia (Müllerian ducts) regress due to the production of testicular anti-Müllerian hormone (AMH). Because of the association between secreted frizzled-related proteins (SFRPs) and apoptosis, their reported developmental expression patterns and the role of WNT signaling in female reproductive tract development, we examined expression of Sfrp2 and Sfrp5 during development of the Müllerian duct in male (XY) and female (XX) mouse embryos. We show that expression of both Sfrp2 and Sfrp5 is dynamic and sexually dimorphic. In addition, the male-specific expression observed for both genes prior to the onset of regression is absent in mutant male embryos that fail to undergo Müllerian duct regression. We identified ENU-induced point mutations in Sfrp5 and Sfrp2 that are predicted to severely disrupt the function of these genes. Male embryos and adults homozygous for these mutations, both individually and in combination, are viable and apparently fertile with no overt abnormalities of reproductive tract development. PMID:16700072

Academic and Demographic Predictors of NCLEX-RN Pass Rates in First- and Second-Degree Accelerated BSN Programs.

PubMed

Kaddoura, Mahmoud A; Flint, Elizabeth P; Van Dyke, Olga; Yang, Qing; Chiang, Li-Chi

Relatively few studies have addressed predictors of first-attempt outcomes (pass-fail) on the National Council Licensure Examination-Registered Nurses (NCLEX-RN) for accelerated BSN programs. The purpose of this study was to compare potential predictors of NCLEX outcomes in graduates of first-degree accelerated (FDA; n=62) and second-degree accelerated (SDA; n=173) BSN programs sharing a common nursing curriculum. In this retrospective study, bivariate analyses and multiple logistic regression assessed significance of selected demographic and academic characteristics as predictors of NCLEX-RN outcomes. FDA graduates were more likely than SDA graduates to fail the NCLEX-RN (P=.0013). FDA graduates were more likely to speak English as a second or additional language (P<.0001), have lower end-of-program GPA and HESI Exit Exam scores (both P<.0001), and have a higher proportions of grades ≤ C (P=.0023). All four variables were significant predictors of NCLEX-RN outcomes within both FDA and SDA programs. The only significant predictors in adjusted logistic regression of NCLEX-RN outcome for the pooled FDA+SDA graduate sample were proportion of grades ≤ C (a predictor of NCLEX-RN failure) and HESI Exit Exam score (a predictor of passing NCLEX-RN). Grades of C or lower on any course may indicate inadequate mastery of critical NCLEX-RN content and increased risk of NCLEX-RN failure. Copyright © 2016 Elsevier Inc. All rights reserved.

Age-Related Imbalance Is Associated With Slower Walking Speed: An Analysis From the National Health and Nutrition Examination Survey.

PubMed

Xie, Yanjun J; Liu, Elizabeth Y; Anson, Eric R; Agrawal, Yuri

Walking speed is an important dimension of gait function and is known to decline with age. Gait function is a process of dynamic balance and motor control that relies on multiple sensory inputs (eg, visual, proprioceptive, and vestibular) and motor outputs. These sensory and motor physiologic systems also play a role in static postural control, which has been shown to decline with age. In this study, we evaluated whether imbalance that occurs as part of healthy aging is associated with slower walking speed in a nationally representative sample of older adults. We performed a cross-sectional analysis of the previously collected 1999 to 2002 National Health and Nutrition Examination Survey (NHANES) data to evaluate whether age-related imbalance is associated with slower walking speed in older adults aged 50 to 85 years (n = 2116). Balance was assessed on a pass/fail basis during a challenging postural task-condition 4 of the modified Romberg Test-and walking speed was determined using a 20-ft (6.10 m) timed walk. Multivariable linear regression was used to evaluate the association between imbalance and walking speed, adjusting for demographic and health-related covariates. A structural equation model was developed to estimate the extent to which imbalance mediates the association between age and slower walking speed. In the unadjusted regression model, inability to perform the NHANES balance task was significantly associated with 0.10 m/s slower walking speed (95% confidence interval: -0.13 to -0.07; P < .01). In the multivariable regression analysis, inability to perform the balance task was significantly associated with 0.06 m/s slower walking speed (95% confidence interval: -0.09 to -0.03; P < .01), an effect size equivalent to 12 years of age. The structural equation model estimated that age-related imbalance mediates 12.2% of the association between age and slower walking speed in older adults. In a nationally representative sample, age-related balance limitation was associated with slower walking speed. Balance impairment may lead to walking speed declines. In addition, reduced static postural control and dynamic walking speed that occur with aging may share common etiologic origins, including the decline in visual, proprioceptive, and vestibular sensory and motor functions.

The role of attitudes about vaccine safety, efficacy, and value in explaining parents' reported vaccination behavior.

PubMed

Lavail, Katherine Hart; Kennedy, Allison Michelle

2013-10-01

To explain vaccine confidence as it related to parents' decisions to vaccinate their children with recommended vaccines, and to develop a confidence measure to efficiently and effectively predict parents' self-reported vaccine behaviors. A sample of parents with at least one child younger than 6 years (n = 376) was analyzed using data from the HealthStyles 2010 survey. Questions were grouped into block variables to create three confidence constructs: value, safety, and efficacy. Regression equations controlling for demographic characteristics were used to identify the confidence construct(s) that best predicted parents' self-reported vaccination decisions (accept all, some, or none of the recommended childhood vaccines). Among the three constructs evaluated, confidence in the value of vaccines, that is the belief that vaccines are important and vaccinating one's children is the right thing to do, was the best predictor of parents' vaccine decisions, F(2, 351) = 119.199, p < .001. When combined into a block variable for analysis, two survey items measuring confidence in the value of vaccines accounted for 40% of the variance in parents' self-reported vaccine decisions. Confidence in the safety or efficacy of vaccines failed to account for additional significant variance in parent-reported vaccination behavior. Confidence in the value of vaccines is a helpful predictor of parent-reported vaccination behavior. Attitudinal constructs of confidence in the safety and efficacy of vaccines failed to account for additional significant variance in parents' vaccination behaviors. Future research should assess the role of vaccine knowledge and tangible barriers, such as access and cost, to further explain parents' vaccination behaviors.

Aspects of energy transitions: History and determinants

NASA Astrophysics Data System (ADS)

O'Connor, Peter A.

Energy intensity in the U.S. from 1780 to 2010 shows a declining trend when traditional energy is included, in contrast to the "inverted U-curve" seen when only commercial energy is considered. The analysis quantifies use of human and animal muscle power, wind and water power, biomass, harvested ice, fossil fuels, and nuclear power. Historical prices are provided for many energy resources. The analysis reaffirms the importance of innovation in conversion technologies in energy transitions. An increase in energy intensity in the early 20th century is explained by diminishing returns to pre-electric manufacturing systems, which produced a transformation in manufacturing. In comparison to similar studies for other countries, the U.S. has generally higher energy intensity. A population-weighted series of heating degree days and cooling degree days partially explains differences in energy intensity. Series are developed for 231 countries and territories with multiple reference temperatures, with a "wet-bulb" series accounting for the effects of humidity. Other variables considered include energy prices, income per capita, and governance indices. A panel regression of thirty-two countries from 1995 to 2010 establishes GDP per capita and share of primary energy as determinants of energy intensity, but fails to establish statistical significance of the climate variables. A group mean regression finds average heating and cooling degree days to be significant predictors of average energy intensity over the study period, increasing energy intensity by roughly 1.5 kJ per 2005 international dollar for each annual degree day. Group mean regression results explain differences in countries' average energy intensity, but not changes within a country over time. Energy Return on Investment (EROI) influences the economic competitiveness and environmental impacts of an energy resource and is one driver of energy transitions. The EROI of U.S. petroleum production has declined since 1972, with a partial rebound in the 1980s and 1990s. External Energy Return (EER), which excludes the consumption of energy from within the resource, falls by two-thirds from 1972 to 2007. A literature review finds the projected EROI of oil shale to be much lower than the EROI of U.S. petroleum production.

Comparison of four methods for deriving hospital standardised mortality ratios from a single hierarchical logistic regression model.

PubMed

Mohammed, Mohammed A; Manktelow, Bradley N; Hofer, Timothy P

2016-04-01

There is interest in deriving case-mix adjusted standardised mortality ratios so that comparisons between healthcare providers, such as hospitals, can be undertaken in the controversial belief that variability in standardised mortality ratios reflects quality of care. Typically standardised mortality ratios are derived using a fixed effects logistic regression model, without a hospital term in the model. This fails to account for the hierarchical structure of the data - patients nested within hospitals - and so a hierarchical logistic regression model is more appropriate. However, four methods have been advocated for deriving standardised mortality ratios from a hierarchical logistic regression model, but their agreement is not known and neither do we know which is to be preferred. We found significant differences between the four types of standardised mortality ratios because they reflect a range of underlying conceptual issues. The most subtle issue is the distinction between asking how an average patient fares in different hospitals versus how patients at a given hospital fare at an average hospital. Since the answers to these questions are not the same and since the choice between these two approaches is not obvious, the extent to which profiling hospitals on mortality can be undertaken safely and reliably, without resolving these methodological issues, remains questionable. © The Author(s) 2012.

Seasonally and experimentally induced changes in testicular function of the Australian bush rat (Rattus fuscipes).

PubMed

Irby, D C; Kerr, J B; Risbridger, G P; de Kretser, D M

1984-03-01

Serum concentrations of LH, FSH and testosterone were measured monthly throughout the year in male bush rats. Testicular size and ultrastructure, LH/hCG, FSH and oestradiol receptors and the response of the pituitary to LHRH were also recorded. LH and FSH rose in parallel with an increase in testicular size after the winter solstice with peak gonadotrophin levels in the spring (September). The subsequent fall in LH and FSH levels was associated with a rise in serum testosterone which reached peak levels during summer (December and January). In February serum testosterone levels and testicular size declined in parallel, while the pituitary response to an LHRH injection was maximal during late summer. The number of LH/hCG, FSH and oestradiol receptors per testis were all greatly reduced in the regressed testes when compared to active testes. In a controlled environment of decreased lighting (shortened photoperiod), temperature and food quality, the testes of sexually active adult males regressed at any time of the year, the resultant testicular morphology and endocrine status being identical to that of wild rats in the non-breeding season. Full testicular regression was achieved only when the photoperiod, temperature and food quality were changed: experiments in which only one or two of these factors were altered failed to produce complete sexual regression.

A Meta-Analysis of Reliability Coefficients in Second Language Research

ERIC Educational Resources Information Center

Plonsky, Luke; Derrick, Deirdre J.

2016-01-01

Ensuring internal validity in quantitative research requires, among other conditions, reliable instrumentation. Unfortunately, however, second language (L2) researchers often fail to report and even more often fail to interpret reliability estimates beyond generic benchmarks for acceptability. As a means to guide interpretations of such estimates,…

An analysis of highway condemnation cases under the provisions of Senate Bill 724 : comparisons of jury and commission awards : final report.

DOT National Transportation Integrated Search

1997-01-01

The Virginia Department of Transportation (VDOT) may legally condemn land for road improvements if all purchase negotiations with the landowner fail. If all further negotiations fail, just compensation for the landowner is decided in court by a five ...

Simulating land-use changes by incorporating spatial autocorrelation and self-organization in CLUE-S modeling: a case study in Zengcheng District, Guangzhou, China

NASA Astrophysics Data System (ADS)

Mei, Zhixiong; Wu, Hao; Li, Shiyun

2018-06-01

The Conversion of Land Use and its Effects at Small regional extent (CLUE-S), which is a widely used model for land-use simulation, utilizes logistic regression to estimate the relationships between land use and its drivers, and thus, predict land-use change probabilities. However, logistic regression disregards possible spatial autocorrelation and self-organization in land-use data. Autologistic regression can depict spatial autocorrelation but cannot address self-organization, while logistic regression by considering only self-organization (NElogistic regression) fails to capture spatial autocorrelation. Therefore, this study developed a regression (NE-autologistic regression) method, which incorporated both spatial autocorrelation and self-organization, to improve CLUE-S. The Zengcheng District of Guangzhou, China was selected as the study area. The land-use data of 2001, 2005, and 2009, as well as 10 typical driving factors, were used to validate the proposed regression method and the improved CLUE-S model. Then, three future land-use scenarios in 2020: the natural growth scenario, ecological protection scenario, and economic development scenario, were simulated using the improved model. Validation results showed that NE-autologistic regression performed better than logistic regression, autologistic regression, and NE-logistic regression in predicting land-use change probabilities. The spatial allocation accuracy and kappa values of NE-autologistic-CLUE-S were higher than those of logistic-CLUE-S, autologistic-CLUE-S, and NE-logistic-CLUE-S for the simulations of two periods, 2001-2009 and 2005-2009, which proved that the improved CLUE-S model achieved the best simulation and was thereby effective to a certain extent. The scenario simulation results indicated that under all three scenarios, traffic land and residential/industrial land would increase, whereas arable land and unused land would decrease during 2009-2020. Apparent differences also existed in the simulated change sizes and locations of each land-use type under different scenarios. The results not only demonstrate the validity of the improved model but also provide a valuable reference for relevant policy-makers.

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

PubMed

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.

Prevalence and determinants of non-standard motorcycle safety helmets amongst food delivery workers in Selangor and Kuala Lumpur.

PubMed

Kulanthayan, S; See, Lai Git; Kaviyarasu, Y; Nor Afiah, M Z

2012-05-01

Almost half of the global traffic crashes involve vulnerable groups such as pedestrian, cyclists and two-wheeler users. The main objective of this study was to determine the factors that influence standard of the safety helmets used amongst food delivery workers by presence of Standard and Industrial Research Institute of Malaysia (SIRIM) certification label. A cross sectional study was conducted amongst 150 food delivery workers from fast food outlets in the vicinity of Selangor and Kuala Lumpur. During observation, safety helmets were classified as standard safety helmet in the presence of SIRIM label and non-standard in the absence of the label. They were approached for questionnaire participation once consent was obtained and were requested to exchange their safety helmet voluntarily with a new one after the interview. Data analysis was carried out using SPSS. Chi square and logistic regression analysis was applied to determine the significance and odds ratio of the variables studied, respectively (penetration test, age, education level, knowledge, crash history, types of safety helmet, marital status and years of riding experience) against the presence of SIRIM label. The response rate for this study was 85.2%. The prevalence of non-standard helmets use amongst fast food delivery workers was 55.3%. Safety helmets that failed the penetration test had higher odds of being non-standard helmets compared with safety helmets passing the test. Types of safety helmet indicated half-shell safety helmets had higher odds to be non-standard safety helmets compared to full-shell safety helmets. Riders with more years of riding experience were in high odds of wearing non-standard safety helmets compared to riders with less riding experience. Non-standard (non-SIRIM approved) helmets were more likely to be half-shell helmets, were more likely to fail the standards penetration test, and were more likely to be worn by older, more experienced riders. The implications of these findings are discussed. Copyright © 2011 Elsevier Ltd. All rights reserved.

Does the Rotator Cuff Tear Pattern Influence Clinical Outcomes After Surgical Repair?

PubMed Central

Watson, Scott; Allen, Benjamin; Robbins, Chris; Bedi, Asheesh; Gagnier, Joel J.; Miller, Bruce

2018-01-01

Background: Limited literature exists regarding the influence of rotator cuff tear morphology on patient outcomes. Purpose: To determine the effect of rotator cuff tear pattern (crescent, U-shape, L-shape) on patient-reported outcomes after rotator cuff repair. Study Design: Cohort study; Level of evidence, 3. Methods: Patients undergoing arthroscopic repair of known full-thickness rotator cuff tears were observed prospectively at regular intervals from baseline to 1 year. The tear pattern was classified at the time of surgery as crescent, U-shaped, or L-shaped. Primary outcome measures were the Western Ontario Rotator Cuff Index (WORC), the American Shoulder and Elbow Surgeons (ASES), and a visual analog scale (VAS) for pain. The tear pattern was evaluated as the primary predictor while controlling for variables known to affect rotator cuff outcomes. Mixed-methods regression and analysis of variance (ANOVA) were used to examine the effects of tear morphology on patient-reported outcomes after surgical repair from baseline to 1 year. Results: A total of 82 patients were included in the study (53 male, 29 female; mean age, 58 years [range, 41-75 years]). A crescent shape was the most common tear pattern (54%), followed by U-shaped (25%) and L-shaped tears (21%). There were no significant differences in outcome scores between the 3 groups at baseline. All 3 groups showed statistically significant improvement from baseline to 1 year, but analysis failed to show any predictive effect in the change in outcome scores from baseline to 1 year for the WORC, ASES, or VAS when tear pattern was the primary predictor. Further ANOVA also failed to show any significant difference in the change in outcome scores from baseline to 1 year for the WORC (P = .96), ASES (P = .71), or VAS (P = .86). Conclusion: Rotator cuff tear pattern is not a predictor of functional outcomes after arthroscopic rotator cuff repair. PMID:29623283

Does the Rotator Cuff Tear Pattern Influence Clinical Outcomes After Surgical Repair?

PubMed

Watson, Scott; Allen, Benjamin; Robbins, Chris; Bedi, Asheesh; Gagnier, Joel J; Miller, Bruce

2018-03-01

Limited literature exists regarding the influence of rotator cuff tear morphology on patient outcomes. To determine the effect of rotator cuff tear pattern (crescent, U-shape, L-shape) on patient-reported outcomes after rotator cuff repair. Cohort study; Level of evidence, 3. Patients undergoing arthroscopic repair of known full-thickness rotator cuff tears were observed prospectively at regular intervals from baseline to 1 year. The tear pattern was classified at the time of surgery as crescent, U-shaped, or L-shaped. Primary outcome measures were the Western Ontario Rotator Cuff Index (WORC), the American Shoulder and Elbow Surgeons (ASES), and a visual analog scale (VAS) for pain. The tear pattern was evaluated as the primary predictor while controlling for variables known to affect rotator cuff outcomes. Mixed-methods regression and analysis of variance (ANOVA) were used to examine the effects of tear morphology on patient-reported outcomes after surgical repair from baseline to 1 year. A total of 82 patients were included in the study (53 male, 29 female; mean age, 58 years [range, 41-75 years]). A crescent shape was the most common tear pattern (54%), followed by U-shaped (25%) and L-shaped tears (21%). There were no significant differences in outcome scores between the 3 groups at baseline. All 3 groups showed statistically significant improvement from baseline to 1 year, but analysis failed to show any predictive effect in the change in outcome scores from baseline to 1 year for the WORC, ASES, or VAS when tear pattern was the primary predictor. Further ANOVA also failed to show any significant difference in the change in outcome scores from baseline to 1 year for the WORC ( P = .96), ASES ( P = .71), or VAS ( P = .86). Rotator cuff tear pattern is not a predictor of functional outcomes after arthroscopic rotator cuff repair.

Adherence to Drug-Refill Is a Useful Early Warning Indicator of Virologic and Immunologic Failure among HIV Patients on First-Line ART in South Africa

PubMed Central

El-Khatib, Ziad; Katzenstein, David; Marrone, Gaetano; Laher, Fatima; Mohapi, Lerato; Petzold, Max; Morris, Lynn; Ekström, Anna Mia

2011-01-01

Background Affordable strategies to prevent treatment failure on first-line regimens among HIV patients are essential for the long-term success of antiretroviral therapy (ART) in sub-Saharan Africa. WHO recommends using routinely collected data such as adherence to drug-refill visits as early warning indicators. We examined the association between adherence to drug-refill visits and long-term virologic and immunologic failure among non-nucleoside reverse transcriptase inhibitor (NNRTI) recipients in South Africa. Methods In 2008, 456 patients on NNRTI-based ART for a median of 44 months (range 12–99 months; 1,510 person-years) were enrolled in a retrospective cohort study in Soweto. Charts were reviewed for clinical characteristics before and during ART. Multivariable logistic regression and Kaplan-Meier survival analysis assessed associations with virologic (two repeated VL>50 copies/ml) and immunologic failure (as defined by WHO). Results After a median of 15 months on ART, 19% (n = 88) and 19% (n = 87) had failed virologically and immunologically respectively. A cumulative adherence of <95% to drug-refill visits was significantly associated with both virologic and immunologic failure (p<0.01). In the final multivariable model, risk factors for virologic failure were incomplete adherence (OR 2.8, 95%CI 1.2–6.7), and previous exposure to single-dose nevirapine or any other antiretrovirals (adj. OR 2.1, 95%CI 1.2–3.9), adjusted for age and sex. In Kaplan-Meier analysis, the virologic failure rate by month 48 was 19% vs. 37% among adherent and non-adherent patients respectively (logrank p value = 0.02). Conclusion One in five failed virologically after a median of 15 months on ART. Adherence to drug-refill visits works as an early warning indicator for both virologic and immunologic failure. PMID:21408071

Augmented reality telementoring (ART) platform: a randomized controlled trial to assess the efficacy of a new surgical education technology.

PubMed

Vera, Angelina M; Russo, Michael; Mohsin, Adnan; Tsuda, Shawn

2014-12-01

Laparoscopic skills training has evolved over recent years. However, conveying a mentor's directions using conventional methods, without realistic on-screen visual cues, can be difficult and confusing. To facilitate laparoscopic skill transference, an augmented reality telementoring (ART) platform was designed to overlay the instruments of a mentor onto the trainee's laparoscopic monitor. The aim of this study was to compare the effectiveness of this new teaching modality to traditional methods in novices performing an intracorporeal suturing task. Nineteen pre-medical and medical students were randomized into traditional mentoring (n = 9) and ART (n = 10) groups for a laparoscopic suturing and knot-tying task. Subjects received either traditional mentoring or ART for 1 h on the validated fundamentals of laparoscopic surgery intracorporeal suturing task. Tasks for suturing were recorded and scored for time and errors. Results were analyzed using means, standard deviation, power regression analysis, correlation coefficient, analysis of variance, and student's t test. Using Wright's cumulative average model (Y = aX (b)) the learning curve slope was significantly steeper, demonstrating faster skill acquisition, for the ART group (b = -0.567, r (2) = 0.92) than the control group (b = -0.453, r (2) = 0.74). At the end of 10 repetitions or 1 h of practice, the ART group was faster versus traditional (mean 167.4 vs. 242.4 s, p = 0.014). The ART group also had fewer fails (8) than the traditional group (13). The ART Platform may be a more effective training technique in teaching laparoscopic skills to novices compared to traditional methods. ART conferred a shorter learning curve, which was more pronounced in the first 4 trials. ART reduced the number of failed attempts and resulted in faster suture times by the end of the training session. ART may be a more effective training tool in laparoscopic surgical training for complex tasks than traditional methods.

U.S. Food safety and Inspection Service testing for Salmonella in selected raw meat and poultry products in the United States, 1998 through 2003: an establishment-level analysis.

PubMed

Eblen, Denise R; Barlow, Kristina E; Naugle, Alecia Larew

2006-11-01

The U.S. Food Safety and Inspection Service (FSIS) pathogen reduction-hazard analysis critical control point systems final rule, published in 1996, established Salmonella performance standards for broiler chicken, cow and bull, market hog, and steer and heifer carcasses and for ground beef, chicken, and turkey meat. In 1998, the FSIS began testing to verify that establishments are meeting performance standards. Samples are collected in sets in which the number of samples is defined but varies according to product class. A sample set fails when the number of positive Salmonella samples exceeds the maximum number of positive samples allowed under the performance standard. Salmonella sample sets collected at 1,584 establishments from 1998 through 2003 were examined to identify factors associated with failure of one or more sets. Overall, 1,282 (80.9%) of establishments never had failed sets. In establishments that did experience set failure(s), generally the failed sets were collected early in the establishment testing history, with the exception of broiler establishments where failure(s) occurred both early and late in the course of testing. Small establishments were more likely to have experienced a set failure than were large or very small establishments, and broiler establishments were more likely to have failed than were ground beef, market hog, or steer-heifer establishments. Agency response to failed Salmonella sample sets in the form of in-depth verification reviews and related establishment-initiated corrective actions have likely contributed to declines in the number of establishments that failed sets. A focus on food safety measures in small establishments and broiler processing establishments should further reduce the number of sample sets that fail to meet the Salmonella performance standard.

Regression: The Apple Does Not Fall Far From the Tree.

PubMed

Vetter, Thomas R; Schober, Patrick

2018-05-15

Researchers and clinicians are frequently interested in either: (1) assessing whether there is a relationship or association between 2 or more variables and quantifying this association; or (2) determining whether 1 or more variables can predict another variable. The strength of such an association is mainly described by the correlation. However, regression analysis and regression models can be used not only to identify whether there is a significant relationship or association between variables but also to generate estimations of such a predictive relationship between variables. This basic statistical tutorial discusses the fundamental concepts and techniques related to the most common types of regression analysis and modeling, including simple linear regression, multiple regression, logistic regression, ordinal regression, and Poisson regression, as well as the common yet often underrecognized phenomenon of regression toward the mean. The various types of regression analysis are powerful statistical techniques, which when appropriately applied, can allow for the valid interpretation of complex, multifactorial data. Regression analysis and models can assess whether there is a relationship or association between 2 or more observed variables and estimate the strength of this association, as well as determine whether 1 or more variables can predict another variable. Regression is thus being applied more commonly in anesthesia, perioperative, critical care, and pain research. However, it is crucial to note that regression can identify plausible risk factors; it does not prove causation (a definitive cause and effect relationship). The results of a regression analysis instead identify independent (predictor) variable(s) associated with the dependent (outcome) variable. As with other statistical methods, applying regression requires that certain assumptions be met, which can be tested with specific diagnostics.

Investigating the role of health care at birth on inequalities in neonatal survival: evidence from Bangladesh

PubMed Central

2013-01-01

Introduction In countries such as Bangladesh many women may only seek skilled care at birth when complications become evident. This often results in higher neonatal mortality for women who give birth in institutions than for those that give birth at home. However, we hypothesise that this apparent excess mortality is concentrated among less advantaged women. The aim of this paper is to examine the association between place of birth and neonatal mortality in Bangladesh, and how this varies by socio-economic status. Methodology The study is based on pooled data from four Bangladesh Demographic and Household Surveys, and uses descriptive analysis and binomial multivariate logistic regression. It uses regression models stratified for place of delivery to examine the impact of socio-economic status and place of residence on neonatal mortality. Results Poor women from rural areas and those with no education who gave birth in institutions had much worse outcomes than those who gave birth at home. There is no difference for more wealthy women. There is a much stronger socio-economic gradient in neonatal mortality for women who gave birth in institutions than those who delivered at home. Conclusion In Bangladesh babies from lower socio-economic groups and particularly those in rural areas have very poor outcomes if born in a facility. This suggests poorer, rural and less educated women are failing to obtain the timely access to quality maternal health care services needed to improve newborn outcomes. PMID:23496964

Estimating conditional proportion curves by regression residuals.

PubMed

Han, Bing; Lim, Nelson

2010-06-15

Researchers often derive a categorical outcome from an observed continuous measurement y. For example, human obesity status can be defined by the body mass index. They proceed to estimate the conditional proportion curve p(x) = P(y

Statistical analysis of factors affecting landslide distribution in the new Madrid seismic zone, Tennessee and Kentucky

USGS Publications Warehouse

Jibson, R.W.; Keefer, D.K.

1989-01-01

More than 220 large landslides along the bluffs bordering the Mississippi alluvial plain between Cairo, Ill., and Memphis, Tenn., are analyzed by discriminant analysis and multiple linear regression to determine the relative effects of slope height and steepness, stratigraphic variation, slope aspect, and proximity to the hypocenters of the 1811-12 New Madrid, Mo., earthquakes on the distribution of these landslides. Three types of landslides are analyzed: (1) old, coherent slumps and block slides, which have eroded and revegetated features and no active analogs in the area; (2) old earth flows, which are also eroded and revegetated; and (3) young rotational slumps, which are present only along near-river bluffs, and which are the only young, active landslides in the area. Discriminant analysis shows that only one characteristic differs significantly between bluffs with and without young rotational slumps: failed bluffs tend to have sand and clay at their base, which may render them more susceptible to fluvial erosion. Bluffs having old coherent slides are significantly higher, steeper, and closer to the hypocenters of the 1811-12 earthquakes than bluffs without these slides. Bluffs having old earth flows are likewise higher and closer to the earthquake hypocenters. Multiple regression analysis indicates that the distribution of young rotational slumps is affected most strongly by slope steepness: about one-third of the variation in the distribution is explained by variations in slope steepness. The distribution of old coherent slides and earth flows is affected most strongly by slope height, but the proximity to the hypocenters of the 1811-12 earthquakes also significantly affects the distribution. The results of the statistical analyses indicate that the only recently active landsliding in the area is along actively eroding river banks, where rotational slumps formed as bluffs are undercut by the river. The analyses further indicate that the old coherent slides and earth flows in the area are spatially related to the 1811-12 earthquake hypocenters and were thus probably triggered by those earthquakes. These results are consistent with findings of other recent investigations of landslides in the area that presented field, historical, and analytical evidence to demonstrate that old landslides in the area formed during the 1811-12 New Madrid earthquakes. Results of the multiple linear regression can also be used to approximate the relative susceptibility of the bluffs in the study area to seismically induced landsliding. ?? 1989.

Applied Multiple Linear Regression: A General Research Strategy

ERIC Educational Resources Information Center

Smith, Brandon B.

1969-01-01

Illustrates some of the basic concepts and procedures for using regression analysis in experimental design, analysis of variance, analysis of covariance, and curvilinear regression. Applications to evaluation of instruction and vocational education programs are illustrated. (GR)

Test and analysis of a stitched RFI graphite-epoxy panel with a fuel access door

NASA Technical Reports Server (NTRS)

Jegley, Dawn C.; Waters, W. Allen, Jr.

1994-01-01

A stitched RFI graphite-epoxy panel with a fuel access door was analyzed using a finite element analysis and loaded to failure in compression. The panel was initially 56-inches long and 36.75-inches wide and the oval access door was 18-inches long and 15-inches wide. The panel was impact damaged with impact energy of 100 ft-lb prior to compressive loading; however, no impact damage was detectable visually or by A-scan. The panel carried a failure load of 695,000 Ib and global failure strain of .00494 in/in. Analysis indicated the panel would fail due to collapse at a load of 688,100 Ib. The test data indicate that the maximum strain in a region near the access door was .0096 in/in and analysis indicates a local surface strain of .010 in/in at the panel's failure load. The panel did not fail through the impact damage, but instead failed through bolt holes for attachment of the access door in a region of high strain.

Optical coherence tomography findings of bilateral foveal leukemic infiltration.

PubMed

Le, John Q; Braich, Puneet S; Brar, Vikram S

2016-01-01

We report a case of a 59-year-old man with a history of atypical chronic myelogenous leukemia who presented with a several-week history of decreased vision in both eyes. His clinical examination revealed bilateral foveal infiltration, which was also demonstrated on optical coherence tomography. After a failed induction with imatinib (Gleevec(®)), he was treated with omacetaxine (Synribo(®)) with an appropriate hematologic response. As his leukemia improved with chemotherapy, his retinal lesions regressed as demonstrated by serial optical coherence tomography and fundus photographs, with near complete restoration of foveal architecture.

Informal Taxation*

PubMed Central

Olken, Benjamin A.; Singhal, Monica

2011-01-01

Informal payments are a frequently overlooked source of local public finance in developing countries. We use microdata from ten countries to establish stylized facts on the magnitude, form, and distributional implications of this “informal taxation.” Informal taxation is widespread, particularly in rural areas, with substantial in-kind labor payments. The wealthy pay more, but pay less in percentage terms, and informal taxes are more regressive than formal taxes. Failing to include informal taxation underestimates household tax burdens and revenue decentralization in developing countries. We discuss various explanations for and implications of these observed stylized facts. PMID:22199993

Predicting the dissolution kinetics of silicate glasses using machine learning

NASA Astrophysics Data System (ADS)

Anoop Krishnan, N. M.; Mangalathu, Sujith; Smedskjaer, Morten M.; Tandia, Adama; Burton, Henry; Bauchy, Mathieu

2018-05-01

Predicting the dissolution rates of silicate glasses in aqueous conditions is a complex task as the underlying mechanism(s) remain poorly understood and the dissolution kinetics can depend on a large number of intrinsic and extrinsic factors. Here, we assess the potential of data-driven models based on machine learning to predict the dissolution rates of various aluminosilicate glasses exposed to a wide range of solution pH values, from acidic to caustic conditions. Four classes of machine learning methods are investigated, namely, linear regression, support vector machine regression, random forest, and artificial neural network. We observe that, although linear methods all fail to describe the dissolution kinetics, the artificial neural network approach offers excellent predictions, thanks to its inherent ability to handle non-linear data. Overall, we suggest that a more extensive use of machine learning approaches could significantly accelerate the design of novel glasses with tailored properties.

An evaluation of Ontario's Group Education Session (GES) for license renewal of seniors aged 80 and above.

PubMed

Vanlaar, Ward; Hing, Marisela Mainegra; Robertson, Robyn; Mayhew, Dan; Carr, David

2016-02-01

In 1996, the Ministry of Transportation in Ontario (MTO) implemented the Group Education Session (GES), which is a mandatory license renewal program for drivers aged 80 and older. This study describes an evaluation of the GES to assess its impact on road safety in Ontario, as well as its effect on the safety of individual drivers who participated in the program. Time series analysis of senior driver records both before and after implementation of the GES, and logistic regression and survival analysis examining senior driver records prior to, and following, their participation in the GES. Using time series analysis there is some evidence to suggest that the GES had a positive impact on road safety. According to the other analyses, participation in the GES is associated with a decrease in the odds of collisions and convictions, regardless of whether drivers pass their first attempt of the knowledge test or not. In addition, failing the first road test and/or having demerit points are strong indicators of future collision and conviction involvement. Results from this evaluation suggest that the GES has had a protective effect on the safety of senior drivers. The findings and discussion will help MTO improve the GES program and provide insights to other jurisdictions that have, or are considering, introducing new senior driver programs. Copyright © 2015 Elsevier Ltd and National Safety Council. All rights reserved.

Application of dielectric spectroscopy for monitoring high cell density in monoclonal antibody producing CHO cell cultivations.

PubMed

Párta, László; Zalai, Dénes; Borbély, Sándor; Putics, Akos

2014-02-01

The application of dielectric spectroscopy was frequently investigated as an on-line cell culture monitoring tool; however, it still requires supportive data and experience in order to become a robust technique. In this study, dielectric spectroscopy was used to predict viable cell density (VCD) at industrially relevant high levels in concentrated fed-batch culture of Chinese hamster ovary cells producing a monoclonal antibody for pharmaceutical purposes. For on-line dielectric spectroscopy measurements, capacitance was scanned within a wide range of frequency values (100-19,490 kHz) in six parallel cell cultivation batches. Prior to detailed mathematical analysis of the collected data, principal component analysis (PCA) was applied to compare dielectric behavior of the cultivations. PCA analysis resulted in detecting measurement disturbances. By using the measured spectroscopic data, partial least squares regression (PLS), Cole-Cole, and linear modeling were applied and compared in order to predict VCD. The Cole-Cole and the PLS model provided reliable prediction over the entire cultivation including both the early and decline phases of cell growth, while the linear model failed to estimate VCD in the later, declining cultivation phase. In regards to the measurement error sensitivity, remarkable differences were shown among PLS, Cole-Cole, and linear modeling. VCD prediction accuracy could be improved in the runs with measurement disturbances by first derivative pre-treatment in PLS and by parameter optimization of the Cole-Cole modeling.

Patient characteristics as predictors of clinical outcome of distraction in treatment of severe ankle osteoarthritis.

PubMed

Marijnissen, A C A; Hoekstra, M C L; Pré, B C du; van Roermund, P M; van Melkebeek, J; Amendola, A; Maathuis, P; Lafeber, F P J G; Welsing, P M J

2014-01-01

Osteoarthritis (OA) is a slowly progressive joint disease. Joint distraction can be a treatment of choice in case of severe OA. Prediction of failure will facilitate implementation of joint distraction in clinical practice. Patients with severe ankle OA, who underwent joint distraction were included. Survival analysis was performed over 12 years (n = 25 after 12 years). Regression analyses were used to predict failures and clinical benefit at 2 years after joint distraction (n = 111). Survival analysis showed that 44% of the patients failed, 17% within 2 years and 37% within 5 years after joint distraction (n = 48 after 5 years). Survival analysis in subgroups showed that the percentage failure was only different in women (30% after 2 years) versus men (after 11 years still no 30% failure). In the multivariate analyses female gender was predictive for failure 2 years after joint distraction. Gender and functional disability at baseline predicted more pain. Functional disability and pain at baseline were associated with more functional disability. Joint distraction shows a long-term clinical beneficial outcome. However, failure rate is considerable over the years. Female patients have a higher chance of failure during follow-up. Unfortunately, not all potential predictors could be investigated and other clinically significant predictors were not found. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

External Tank Liquid Hydrogen (LH2) Prepress Regression Analysis Independent Review Technical Consultation Report

NASA Technical Reports Server (NTRS)

Parsons, Vickie s.

2009-01-01

The request to conduct an independent review of regression models, developed for determining the expected Launch Commit Criteria (LCC) External Tank (ET)-04 cycle count for the Space Shuttle ET tanking process, was submitted to the NASA Engineering and Safety Center NESC on September 20, 2005. The NESC team performed an independent review of regression models documented in Prepress Regression Analysis, Tom Clark and Angela Krenn, 10/27/05. This consultation consisted of a peer review by statistical experts of the proposed regression models provided in the Prepress Regression Analysis. This document is the consultation's final report.

40 CFR 82.180 - Agency review of SNAP submissions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... until EPA has received data it judges adequate to support analysis of the submission. (4) Letter of... time the Agency perceives a lack of information necessary to reach a SNAP determination, it will... expires even if the Agency fails to reach a decision within the 90-day review period or fails to...

Decision-Tree Analysis for Predicting First-Time Pass/Fail Rates for the NCLEX-RN® in Associate Degree Nursing Students.

PubMed

Chen, Hsiu-Chin; Bennett, Sean

2016-08-01

Little evidence shows the use of decision-tree algorithms in identifying predictors and analyzing their associations with pass rates for the NCLEX-RN(®) in associate degree nursing students. This longitudinal and retrospective cohort study investigated whether a decision-tree algorithm could be used to develop an accurate prediction model for the students' passing or failing the NCLEX-RN. This study used archived data from 453 associate degree nursing students in a selected program. The chi-squared automatic interaction detection analysis of the decision trees module was used to examine the effect of the collected predictors on passing/failing the NCLEX-RN. The actual percentage scores of Assessment Technologies Institute®'s RN Comprehensive Predictor(®) accurately identified students at risk of failing. The classification model correctly classified 92.7% of the students for passing. This study applied the decision-tree model to analyze a sequence database for developing a prediction model for early remediation in preparation for the NCLEXRN. [J Nurs Educ. 2016;55(8):454-457.]. Copyright 2016, SLACK Incorporated.

Recurrence quantification analysis to characterize cyclical components of environmental elemental exposures during fetal and postnatal development

PubMed Central

Austin, Christine; Gennings, Chris; Tammimies, Kristiina; Bölte, Sven; Arora, Manish

2017-01-01

Environmental exposures to essential and toxic elements may alter health trajectories, depending on the timing, intensity, and mixture of exposures. In epidemiologic studies, these factors are typically analyzed as a function of elemental concentrations in biological matrices measured at one or more points in time. Such an approach, however, fails to account for the temporal cyclicity in the metabolism of environmental chemicals, which if perturbed may lead to adverse health outcomes. Here, we conceptualize and apply a non-linear method–recurrence quantification analysis (RQA)–to quantify cyclical components of prenatal and early postnatal exposure profiles for elements essential to normal development, including Zn, Mn, Mg, and Ca, and elements associated with deleterious health effects or narrow tolerance ranges, including Pb, As, and Cr. We found robust evidence of cyclical patterns in the metabolic profiles of nutrient elements, which we validated against randomized twin-surrogate time-series, and further found that nutrient dynamical properties differ from those of Cr, As, and Pb. Furthermore, we extended this approach to provide a novel method of quantifying dynamic interactions between two environmental exposures. To achieve this, we used cross-recurrence quantification analysis (CRQA), and found that elemental nutrient-nutrient interactions differed from those involving toxicants. These rhythmic regulatory interactions, which we characterize in two geographically distinct cohorts, have not previously been uncovered using traditional regression-based approaches, and may provide a critical unit of analysis for environmental and dietary exposures in epidemiological studies. PMID:29112980

A Low Glycaemic Index Diet in Pregnancy Induces DNA Methylation Variation in Blood of Newborns: Results from the ROLO Randomised Controlled Trial.

PubMed

Geraghty, Aisling A; Sexton-Oates, Alexandra; O'Brien, Eileen C; Alberdi, Goiuri; Fransquet, Peter; Saffery, Richard; McAuliffe, Fionnuala M

2018-04-06

The epigenetic profile of the developing fetus is sensitive to environmental influence. Maternal diet has been shown to influence DNA methylation patterns in offspring, but research in humans is limited. We investigated the impact of a low glycaemic index dietary intervention during pregnancy on offspring DNA methylation patterns using a genome-wide methylation approach. Sixty neonates were selected from the ROLO (Randomised cOntrol trial of LOw glycaemic index diet to prevent macrosomia) study: 30 neonates from the low glycaemic index intervention arm and 30 from the control, whose mothers received no specific dietary advice. DNA methylation was investigated in 771,484 CpG sites in free DNA from cord blood serum. Principal component analysis and linear regression were carried out comparing the intervention and control groups. Gene clustering and pathway analysis were also explored. Widespread variation was identified in the newborns exposed to the dietary intervention, accounting for 11% of the total level of DNA methylation variation within the dataset. No association was found with maternal early-pregnancy body mass index (BMI), infant sex, or birthweight. Pathway analysis identified common influences of the intervention on gene clusters plausibly linked to pathways targeted by the intervention, including cardiac and immune functioning. Analysis in 60 additional samples from the ROLO study failed to replicate the original findings. Using a modest-sized discovery sample, we identified preliminary evidence of differential methylation in progeny of mothers exposed to a dietary intervention during pregnancy.

Maintenance Operations in Mission Oriented Protective Posture Level IV (MOPPIV)

DTIC Science & Technology

1987-10-01

Repair FADAC Printed Circuit Board ............. 6 3. Data Analysis Techniques ............................. 6 a. Multiple Linear Regression... ANALYSIS /DISCUSSION ............................... 12 1. Exa-ple of Regression Analysis ..................... 12 S2. Regression results for all tasks...6 * TABLE 9. Task Grouping for Analysis ........................ 7 "TABXLE 10. Remove/Replace H60A3 Power Pack................. 8 TABLE

Why conventional detection methods fail in identifying the existence of contamination events.

PubMed

Liu, Shuming; Li, Ruonan; Smith, Kate; Che, Han

2016-04-15

Early warning systems are widely used to safeguard water security, but their effectiveness has raised many questions. To understand why conventional detection methods fail to identify contamination events, this study evaluates the performance of three contamination detection methods using data from a real contamination accident and two artificial datasets constructed using a widely applied contamination data construction approach. Results show that the Pearson correlation Euclidean distance (PE) based detection method performs better for real contamination incidents, while the Euclidean distance method (MED) and linear prediction filter (LPF) method are more suitable for detecting sudden spike-like variation. This analysis revealed why the conventional MED and LPF methods failed to identify existence of contamination events. The analysis also revealed that the widely used contamination data construction approach is misleading. Copyright © 2016 Elsevier Ltd. All rights reserved.

[Arthrodesis following revision of a knee endoprosthesis. Literature review 1984-1994].

PubMed

Kohn, D; Schmolke, S

1996-04-01

Two percent of primary and 8% of revision total knee replacements are followed by arthrodesis. Today knee arthrodesis is the most important salvage procedure after failed total knee arthroplasty, resection arthroplasty and above-the-knee amputation being the only alternatives. Analysis of the literature between 1984 and 1994 revealed 533 cases treated with arthrodesis of the knee; 403 were done after failed total knee arthroplasty. The fusion rate was 74%. External fixation, intramedullary nail, plates and combinations of these are currently used for fixation. The literature and an analysis of our own patients from 1988 to 1994 showed that arthrodesis after failed arthroplasty is a difficult procedure, and complications often occur. Bone loss of the distal femur and proximal tibia is the one most important prognostic factor. A new classification system for bone loss is presented.

TH-CD-207A-10: Using the Gamma Index to Flag Changes in Anatomy During Radiation Therapy of Head and Neck Cancer

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

Schaly, B; Battista, J; Department of Medical Biophysics, Western University, London, Ontario Canada

Purpose: This article presents a fast algorithm for comparing 3-D anatomy from Cone-Beam CT (CBCT) imaging using the gamma comparison index and to demonstrate how this can be used to flag patients for possible re-planning of treatment. Methods: CBCT scans acquired on a Varian linear accelerator during treatment were used as input to the gamma comparator using thresholds of 5 mm distance to agreement and 30 Hounsfield Unit CT number difference. The fraction 1 CBCT study was initially used as the reference. Should there be a re-plan during treatment, the reference resets to the CBCT study acquired on the daymore » 1 of the re-plan. Histograms of failing pixels (γ > 1) were generated from each 3-D gamma map. An indicator of anatomy congruence, the match quality parameter (MQP), was derived from failed pixel histograms using the 90th percentile gamma value. The MQP was plotted versus fraction number and related to actual repeat computed tomography (re-CT) order dates as decided by a radiation oncologist. From this, decision criteria were derived for the algorithm to “trigger” re-CT consideration and predictive power was scored using receiver-operator characteristic (ROC) analysis. Results: The MQP plot generally showed that the on-line match from CBCT image guidance deteriorated as the treatment progressed due to weight loss and tumor regression. The optimized MQP criteria for triggering re-CT consideration demonstrated high sensitivity and specificity, consistent with actual re-CT order dates within ± 3 fractions. Out of 20 patients that were actually re-planned, the algorithm failed to trigger a re-CT recommendation only twice and this was caused by CBCT ring artifacts. Conclusion: We have demonstrated that gamma comparisons can be used to evaluate CBCT-acquired anatomy pairs and, from this, an algorithm can be “trained” to flag patients for possible re-planning in a manner consistent with local radiation oncology practice.« less

Towards Adaptive Educational Assessments: Predicting Student Performance using Temporal Stability and Data Analytics in Learning Management Systems

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

Thakur, Gautam; Olama, Mohammed M; McNair, Wade

Data-driven assessments and adaptive feedback are becoming a cornerstone research in educational data analytics and involve developing methods for exploring the unique types of data that come from the educational context. For example, predicting college student performance is crucial for both the students and educational institutions. It can support timely intervention to prevent students from failing a course, increasing efficacy of advising functions, and improving course completion rate. In this paper, we present our efforts in using data analytics that enable educationists to design novel data-driven assessment and feedback mechanisms. In order to achieve this objective, we investigate temporal stabilitymore » of students grades and perform predictive analytics on academic data collected from 2009 through 2013 in one of the most commonly used learning management systems, called Moodle. First, we have identified the data features useful for assessments and predicting student outcomes such as students scores in homework assignments, quizzes, exams, in addition to their activities in discussion forums and their total Grade Point Average(GPA) at the same term they enrolled in the course. Second, time series models in both frequency and time domains are applied to characterize the progression as well as overall projections of the grades. In particular, the model analyzed the stability as well as fluctuation of grades among students during the collegiate years (from freshman to senior) and disciplines. Third, Logistic Regression and Neural Network predictive models are used to identify students as early as possible who are in danger of failing the course they are currently enrolled in. These models compute the likelihood of any given student failing (or passing) the current course. The time series analysis indicates that assessments and continuous feedback are critical for freshman and sophomores (even with easy courses) than for seniors, and those assessments may be provided using the predictive models. Numerical results are presented to evaluate and compare the performance of the developed models and their predictive accuracy. Our results show that there are strong ties associated with the first few weeks for coursework and they have an impact on the design and distribution of individual modules.« less

Creep-Rupture Data Analysis - Engineering Application of Regression Techniques. Ph.D. Thesis - North Carolina State Univ.

NASA Technical Reports Server (NTRS)

Rummler, D. R.

1976-01-01

The results are presented of investigations to apply regression techniques to the development of methodology for creep-rupture data analysis. Regression analysis techniques are applied to the explicit description of the creep behavior of materials for space shuttle thermal protection systems. A regression analysis technique is compared with five parametric methods for analyzing three simulated and twenty real data sets, and a computer program for the evaluation of creep-rupture data is presented.

Resting-state functional magnetic resonance imaging: the impact of regression analysis.

PubMed

Yeh, Chia-Jung; Tseng, Yu-Sheng; Lin, Yi-Ru; Tsai, Shang-Yueh; Huang, Teng-Yi

2015-01-01

To investigate the impact of regression methods on resting-state functional magnetic resonance imaging (rsfMRI). During rsfMRI preprocessing, regression analysis is considered effective for reducing the interference of physiological noise on the signal time course. However, it is unclear whether the regression method benefits rsfMRI analysis. Twenty volunteers (10 men and 10 women; aged 23.4 ± 1.5 years) participated in the experiments. We used node analysis and functional connectivity mapping to assess the brain default mode network by using five combinations of regression methods. The results show that regressing the global mean plays a major role in the preprocessing steps. When a global regression method is applied, the values of functional connectivity are significantly lower (P ≤ .01) than those calculated without a global regression. This step increases inter-subject variation and produces anticorrelated brain areas. rsfMRI data processed using regression should be interpreted carefully. The significance of the anticorrelated brain areas produced by global signal removal is unclear. Copyright © 2014 by the American Society of Neuroimaging.

Social deprivation and prognosis in Scottish patients with pulmonary arterial hypertension.

PubMed

Pellino, Katherine; Kerridge, Simon; Church, Colin; Peacock, Andrew J; Crowe, Timothy; Jayasekera, Geeshath; Johnson, Martin K; MacKenzie, Alison M

2018-02-01

Several demographic and clinical factors have prognostic significance in idiopathic pulmonary arterial hypertension (IPAH). Studies in China and the USA have suggested an association between low socioeconomic status and reduced survival. The impact of social deprivation on IPAH survival in the UK is not known.280 patients with IPAH and hereditary PAH (HPAH) attending the Scottish Pulmonary Vascular Unit (Glasgow, UK) were assigned to social deprivation quintiles using the Scottish Index of Multiple Deprivation database. The association between survival and social deprivation quintile was assessed using Cox proportional hazards regression analysis.The distribution of IPAH/HPAH patients was more socially deprived than would be expected based on Scottish citizenry as a whole (Chi-squared 16.16, p=0.003), suggesting referral and access to care is not impeded by socioeconomic status. Univariate analysis demonstrated no significant association between social deprivation and survival (p=0.81), and this association failed to reach significance with inclusion of time, sex and age as covariates in the model (p=0.23). There were no statistically significant correlations between social deprivation and baseline clinical variables of prognostic importance except for age, sex and quality of life.Social deprivation is not a significant referral barrier or prognostic factor for IPAH and HPAH in Scotland. Copyright ©ERS 2018.

Assessing the risk for suicide in schizophrenia according to migration, ethnicity and geographical ancestry.

PubMed

Hettige, Nuwan C; Bani-Fatemi, Ali; Kennedy, James L; De Luca, Vincenzo

2017-02-09

Suicide is a leading cause of mortality among those afflicted by schizophrenia. Previous studies demonstrated that the stressors associated with immigration may lead to an onset of schizophrenia and suicide separately in susceptible individuals. However, no studies have shown whether immigration may lead to suicidal behaviour for individuals with schizophrenia. Our study proposes that an individual's geographical ancestry, ethnicity or migration status may be predictive of suicide risk in schizophrenia. In a sample of 276 participants with schizophrenia spectrum disorders, we conducted cross-sectional assessments to collect clinical information. Self-identified ethnicity and suicide history were collected through self-report questionnaires and interview-based scales. Ancestry was identified using 292 genetic markers from HapMap. Migrants were classified as those who immigrated to Canada during their lifetime. Using a regression analysis, we tested whether a history of migration, ethnicity or geographical ancestry were predictive of a history of suicide attempts. Our analysis failed to demonstrate a significant relationship between suicide history and migration, ethnicity or ancestry. However, ethnicity appears to be significantly associated with the number of psychiatric hospitalizations in our sample. Ethnicity and migration history are not predictive of previous suicide attempts. Ethnicity may be an important demographic factor affecting access to mental health resources and frequency of hospitalizations.

Longitudinal changes in tooth/single-implant relationship and bone topography: an 8-year retrospective analysis.

PubMed

Chang, Moontaek; Wennström, Jan L

2012-06-01

To evaluate longitudinal changes in tooth/implant relationship and bone topography at single implants with a microthreaded, conical marginal portion (Astra Tech ST® implants, Astra Tech AB, Mölndal, Sweden). Thirty-one subjects with single implant-supported restorations in the esthetic zone were included. Radiographs obtained at crown installation and 1, 5, and 8 years of follow-up were analyzed with regard to changes in (1) bone level at the implant and adjacent teeth and (2) vertical position of adjacent teeth relative to the single implant. The mean marginal bone loss amounted to 0.1 mm at both implants and adjacent teeth during the 8 years of follow-up. Regression analysis failed to identify significant explanatory factors for observed variance in bone level change at the adjacent tooth surfaces. Vertical change in position of the teeth relative to the implants was more frequent and significantly greater in incisor compared with premolar tooth region but not associated with gender or age. The marginal bone level at teeth adjacent to single implants with a microthreaded conical marginal part was not influenced by horizontal and vertical tooth-implant distances. Continuous eruption of adjacent teeth may result in infraocclusal positioning of a single-implant restoration. © 2010 Wiley Periodicals, Inc.

Analysis of clinically important factors on the performance of advanced hydraulic, microprocessor-controlled exo-prosthetic knee joints based on 899 trial fittings

PubMed Central

Hahn, Andreas; Lang, Michael; Stuckart, Claudia

2016-01-01

Abstract The objective of this work is to evaluate whether clinically important factors may predict an individual's capability to utilize the functional benefits provided by an advanced hydraulic, microprocessor-controlled exo-prosthetic knee component. This retrospective cross-sectional cohort analysis investigated the data of above knee amputees captured during routine trial fittings. Prosthetists rated the performance indicators showing the functional benefits of the advanced maneuvering capabilities of the device. Subjects were asked to rate their perception. Simple and multiple linear and logistic regression was applied. Data from 899 subjects with demographics typical for the population were evaluated. Ability to vary gait speed, perform toileting, and ascend stairs were identified as the most sensitive performance predictors. Prior C-Leg users showed benefits during advanced maneuvering. Variables showed plausible and meaningful effects, however, could not claim predictive power. Mobility grade showed the largest effect but also failed to be predictive. Clinical parameters such as etiology, age, mobility grade, and others analyzed here do not suffice to predict individual potential. Daily walking distance may pose a threshold value and be part of a predictive instrument. Decisions based solely on single parameters such as mobility grade rating or walking distance seem to be questionable. PMID:27828871

Analysis of clinically important factors on the performance of advanced hydraulic, microprocessor-controlled exo-prosthetic knee joints based on 899 trial fittings.

PubMed

Hahn, Andreas; Lang, Michael; Stuckart, Claudia

2016-11-01

The objective of this work is to evaluate whether clinically important factors may predict an individual's capability to utilize the functional benefits provided by an advanced hydraulic, microprocessor-controlled exo-prosthetic knee component.This retrospective cross-sectional cohort analysis investigated the data of above knee amputees captured during routine trial fittings. Prosthetists rated the performance indicators showing the functional benefits of the advanced maneuvering capabilities of the device. Subjects were asked to rate their perception. Simple and multiple linear and logistic regression was applied.Data from 899 subjects with demographics typical for the population were evaluated. Ability to vary gait speed, perform toileting, and ascend stairs were identified as the most sensitive performance predictors. Prior C-Leg users showed benefits during advanced maneuvering. Variables showed plausible and meaningful effects, however, could not claim predictive power. Mobility grade showed the largest effect but also failed to be predictive.Clinical parameters such as etiology, age, mobility grade, and others analyzed here do not suffice to predict individual potential. Daily walking distance may pose a threshold value and be part of a predictive instrument. Decisions based solely on single parameters such as mobility grade rating or walking distance seem to be questionable.

Can school choice improve more than just academic achievement? An analysis of post-Katrina New Orleans.

PubMed

Hutchinson, Paul L; Ferrell, Natalie; Broussard, Marsha; Brown, Lisanne; Chrestman, Sarah K

2014-04-01

Recent evaluations of school choice school reforms have focused on improving academic achievement but have ignored associations with adolescent health and the risk of interpersonal violence. The innovative school choice model implemented in post-Katrina New Orleans provides a unique opportunity to examine these effects. Using a sample of approximately 1700 students from the 2009 School Health Connection Survey, the relationships between the type of school attended and depression, suicide planning, absences attributable to fears for personal safety, and threats of violence at school are examined. Multivariate regression analysis adjusting for self-selection into the type of school attended-a city-run high-performing school, a state-run failing school, or an independent charter school-estimates the effects of school type on student health. Relative to students at state-run schools, students who choose to attend city-run schools are less likely to plan for suicide or to miss school because they are afraid of becoming victims of violence. These beneficial effects tend to be larger for students traveling from higher violence neighborhoods. The effects for charter schools are similar but less robust. Local school jurisdictions that implement reforms allowing adolescents and their families greater freedom in school choice may also improve adolescent health. © 2014, American School Health Association.

Maternal Alcohol Consumption during Pregnancy and Early Age Leukemia Risk in Brazil.

PubMed

Ferreira, Jeniffer Dantas; Couto, Arnaldo Cézar; Emerenciano, Mariana; Pombo-de-Oliveira, Maria S; Koifman, Sergio

2015-01-01

Objectives. To investigate the association between the maternal alcohol consumption during pregnancy and early age leukemia (EAL) in offspring. Methods. Datasets were analyzed from a case-control study carried out in Brazil during 1999-2007. Data were obtained by maternal interviews using a standardized questionnaire. The present study included 675 children (193 acute lymphoid leukemia (ALL), 59 acute myeloid leukemia (AML), and 423 controls). Unconditional logistic regression was performed, and adjusted odds ratios (adj. OR) on the association between alcohol consumption and EAL were ascertained. Results. Alcohol consumption was reported by 43% of ALL and 39% of AML case mothers and 35.5% of controls'. Beer consumption before and during pregnancy was associated with ALL in crude analysis (OR = 1.54, 95% CI, 1.08-2.19), although in adjusted analysis no statistical significance was found. For weekly intake of ≤1 glass (adj. OR = 1.30, 95% CI, 0.71-2.36) and ≥1 glass/week (adj. OR = 1.47, 95% CI, 0.88-2.46) a potential dose-response was observed (P trend < 0.03). Conclusion. This study failed to support the hypothesis of an increased risk of EAL associated with maternal alcohol intake during pregnancy, neither with the interaction with tobacco nor with alcohol consumption.

Liver transplantation for neonatal hemochromatosis: analysis of the UNOS database.

PubMed

Sheflin-Findling, Shari; Annunziato, Rachel A; Chu, Jaime; Arvelakis, Antonios; Mahon, Danielle; Arnon, Ronen

2015-03-01

NH is the most common identifiable cause of ALF in the neonate. LT is the definitive treatment for neonates with NH who have failed medical therapy. Our aim was to determine the outcomes of LT in infants with NH. Patients (less than one yr of age) with NH who were listed for LT and patients who underwent LT between 1994 and 2013 were identified from the UNOS database for analysis. Risk factors for death and graft loss were analyzed by multivariate logistic regression. Thirty-eight infants with NH with a total of 43 transplants were identified. One- and five-yr patient and graft survival were 84.2%, 81.6%, 71.1%, and 68.4%, respectively. The outcomes for NH were not significantly different when compared to the same age-matched recipients with other causes of ALF. There were no statistically significant risk factors identified for graft loss or death. Ninety infants with NH were listed for LT. Reasons for removal included transplanted (49%), death (27%), too sick to transplant (7%), and improved status (13%). LT for infants with NH has a high rate of graft loss and death; however, outcomes are comparable to the same age-matched recipients with other causes of ALF. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Sources and implications of whole-brain fMRI signals in humans

PubMed Central

Power, Jonathan D; Plitt, Mark; Laumann, Timothy O; Martin, Alex

2016-01-01

Whole-brain fMRI signals are a subject of intense interest: variance in the global fMRI signal (the spatial mean of all signals in the brain) indexes subject arousal, and psychiatric conditions such as schizophrenia and autism have been characterized by differences in the global fMRI signal. Further, vigorous debates exist on whether global signals ought to be removed from fMRI data. However, surprisingly little research has focused on the empirical properties of whole-brain fMRI signals. Here we map the spatial and temporal properties of the global signal, individually, in 1000+ fMRI scans. Variance in the global fMRI signal is strongly linked to head motion, to hardware artifacts, and to respiratory patterns and their attendant physiologic changes. Many techniques used to prepare fMRI data for analysis fail to remove these uninteresting kinds of global signal fluctuations. Thus, many studies include, at the time of analysis, prominent global effects of yawns, breathing changes, and head motion, among other signals. Such artifacts will mimic dynamic neural activity and will spuriously alter signal covariance throughout the brain. Methods capable of isolating and removing global artifactual variance while preserving putative “neural” variance are needed; this paper adopts no position on the topic of global signal regression. PMID:27751941

Standards for Standardized Logistic Regression Coefficients

ERIC Educational Resources Information Center

Menard, Scott

2011-01-01

Standardized coefficients in logistic regression analysis have the same utility as standardized coefficients in linear regression analysis. Although there has been no consensus on the best way to construct standardized logistic regression coefficients, there is now sufficient evidence to suggest a single best approach to the construction of a…

Association between prenatal exposure to ambient diesel particulate matter and perchloroethylene with children's 3rd grade standardized test scores

PubMed Central

Stingone, Jeanette A.; McVeigh, Katharine H.; Claudio, Luz

2016-01-01

The objective of this research was to determine if prenatal exposure to two common urban air pollutants, diesel and perchloroethylene, affects children's 3rd grade standardized test scores in mathematics and English language arts (ELA). Exposure estimates consisted of annual average ambient concentrations of diesel particulate matter and perchloroethylene obtained from the Environmental Protection Agency's 1996 National Air Toxics Assessment for the residential census tract at birth. Outcome data consisted of linked birth and educational records for 201,559 singleton, non-anomalous children born between 1994-1998 who attended New York City public schools. Quantile regression models were used to estimate the effects of these exposures on multiple points within the continuous distribution of standardized test scores. Modified Poisson regression models were used to calculate risk ratios (RR) and 95% confidence intervals (CI) of failing to meet curricula standards, an indicator derived from test scores. Models were adjusted for a number of maternal, neighborhood and childhood factors. Results showed that math scores were approximately 6% of a standard deviation lower for children exposed to the highest levels of both pollutants as compared to children with low levels of both pollutants. Children exposed to high levels of both pollutants also had the largest risk of failing to meet math test standards when compared to children with low levels of exposure to the pollutants (RR 1.10 95%CI 1.07,1.12 RR high perchloroethylene only 1.03 95%CI 1.00,1.06; RR high diesel PM only 1.02 95%CI 0.99,1.06). There was no association observed between exposure to only one of the pollutants and failing to meet ELA standards. This study provides preliminary evidence of associations between prenatal exposure to urban air pollutants and lower academic outcomes. Additionally, these findings suggest that individual pollutants may additively impact health and point to the need to study the collective effects of air pollutant mixtures. Key Words: air toxics, academic outcomes, urban health, tetrachloroethylene, air pollutant mixtures PMID:27058443

Association between prenatal exposure to ambient diesel particulate matter and perchloroethylene with children's 3rd grade standardized test scores.

PubMed

Stingone, Jeanette A; McVeigh, Katharine H; Claudio, Luz

2016-07-01

The objective of this research was to determine if prenatal exposure to two common urban air pollutants, diesel and perchloroethylene, affects children's 3rd grade standardized test scores in mathematics and English language arts (ELA). Exposure estimates consisted of annual average ambient concentrations of diesel particulate matter and perchloroethylene obtained from the Environmental Protection Agency's 1996 National Air Toxics Assessment for the residential census tract at birth. Outcome data consisted of linked birth and educational records for 201,559 singleton, non-anomalous children born between 1994 and 1998 who attended New York City public schools. Quantile regression models were used to estimate the effects of these exposures on multiple points within the continuous distribution of standardized test scores. Modified Poisson regression models were used to calculate risk ratios (RR) and 95% confidence intervals (CI) of failing to meet curricula standards, an indicator derived from test scores. Models were adjusted for a number of maternal, neighborhood and childhood factors. Results showed that math scores were approximately 6% of a standard deviation lower for children exposed to the highest levels of both pollutants as compared to children with low levels of both pollutants. Children exposed to high levels of both pollutants also had the largest risk of failing to meet math test standards when compared to children with low levels of exposure to the pollutants (RR 1.10 95%CI 1.07,1.12 RR high perchloroethylene only 1.03 95%CI 1.00,1.06; RR high diesel PM only 1.02 95%CI 0.99,1.06). There was no association observed between exposure to the pollutants and failing to meet ELA standards. This study provides preliminary evidence of associations between prenatal exposure to urban air pollutants and lower academic outcomes. Additionally, these findings suggest that individual pollutants may additively impact health and point to the need to study the collective effects of air pollutant mixtures. air toxics, academic outcomes, urban health, tetrachloroethylene, air pollutant mixtures. Copyright © 2016 Elsevier Inc. All rights reserved.

Linear regression analysis: part 14 of a series on evaluation of scientific publications.

PubMed

Schneider, Astrid; Hommel, Gerhard; Blettner, Maria

2010-11-01

Regression analysis is an important statistical method for the analysis of medical data. It enables the identification and characterization of relationships among multiple factors. It also enables the identification of prognostically relevant risk factors and the calculation of risk scores for individual prognostication. This article is based on selected textbooks of statistics, a selective review of the literature, and our own experience. After a brief introduction of the uni- and multivariable regression models, illustrative examples are given to explain what the important considerations are before a regression analysis is performed, and how the results should be interpreted. The reader should then be able to judge whether the method has been used correctly and interpret the results appropriately. The performance and interpretation of linear regression analysis are subject to a variety of pitfalls, which are discussed here in detail. The reader is made aware of common errors of interpretation through practical examples. Both the opportunities for applying linear regression analysis and its limitations are presented.

An improved multiple linear regression and data analysis computer program package

NASA Technical Reports Server (NTRS)

Sidik, S. M.

1972-01-01

NEWRAP, an improved version of a previous multiple linear regression program called RAPIER, CREDUC, and CRSPLT, allows for a complete regression analysis including cross plots of the independent and dependent variables, correlation coefficients, regression coefficients, analysis of variance tables, t-statistics and their probability levels, rejection of independent variables, plots of residuals against the independent and dependent variables, and a canonical reduction of quadratic response functions useful in optimum seeking experimentation. A major improvement over RAPIER is that all regression calculations are done in double precision arithmetic.

Dancing in a Minefield: An Analysis of Turnaround Specialists in Arizona Schools

ERIC Educational Resources Information Center

McMillie, Kyann L.

2010-01-01

In 2008, educational leaders from the Arizona Department of Education (ADE) assigned a group of turnaround specialists to work in four failing public schools in a large, urban school district in Phoenix, Arizona in hopes of improving those schools. The utilization of turnaround specialists in failing schools was Arizona's method of enacting…

Why Children Fail in First Grade in Rio Grande do Sul: Implications for Policy and Research.

ERIC Educational Resources Information Center

Wolff, Laurence

This study, exploring why first grade children from Rio Grande do Sul, Brazil, fail in school, utilized computerized techniques of statistical analysis to measure the relationships of various school and family characteristics with student achievement. Four types of schools--urban state, rural state, municipal, and private--were used to test the…

An Unfulfilled Dream of an Urban Community School for Girls: A Failed Experiment in Educational Reform

ERIC Educational Resources Information Center

Doyle, Kerri

2013-01-01

This research presents the qualitative case study of an urban community school initiative that began as an educational reform effort and that ultimately failed. The process of emergence for this school and factors leading to its collapse are described through participant interviews and document analysis. Nationally, policy reformers,…

Factors Associated with Failure of Non-invasive Positive Pressure Ventilation in a Critical Care Helicopter Emergency Medical Service.

PubMed

Lee, James S; O'Dochartaigh, Domhnall; MacKenzie, Mark; Hudson, Darren; Couperthwaite, Stephanie; Villa-Roel, Cristina; Rowe, Brian H

2015-06-01

Non-invasive positive pressure ventilation (NIPPV) is used to treat severe acute respiratory distress. Prehospital NIPPV has been associated with a reduction in both in-hospital mortality and the need for invasive ventilation. The authors of this study examined factors associated with NIPPV failure and evaluated the impact of NIPPV on scene times in a critical care helicopter Emergency Medical Service (HEMS). Non-invasive positive pressure ventilation failure was defined as the need for airway intervention or alternative means of ventilatory support. A retrospective chart review of consecutive patients where NIPPV was completed in a critical care HEMS was conducted. Factors associated with NIPPV failure in univariate analyses and from published literature were included in a multivariable, logistic regression model. From a total of 44 patients, NIPPV failed in 14 (32%); a Glasgow Coma Scale (GCS)<15 at HEMS arrival was associated independently with NIPPV failure (adjusted odds ratio 13.9; 95% CI, 2.4-80.3; P=.003). Mean scene times were significantly longer in patients who failed NIPPV when compared with patients in whom NIPPV was successful (95 minutes vs 51 minutes; 39.4 minutes longer; 95% CI, 16.2-62.5; P=.001). Patients with a decreased level of consciousness were more likely to fail NIPPV. Furthermore, patients who failed NIPPV had significantly longer scene times. The benefits of NIPPV should be balanced against risks of long scene times by HEMS providers. Knowing risk factors of NIPPV failure could assist HEMS providers to make the safest decision for patients on whether to initiate NIPPV or proceed directly to endotracheal intubation prior to transport.

The relationship between internal medicine residency graduate performance on the ABIM certifying examination, yearly in-service training examinations, and the USMLE Step 1 examination.

PubMed

Kay, Cynthia; Jackson, Jeffrey L; Frank, Michael

2015-01-01

To explore the relationship between United States Medical Licensing Examination (USMLE) Step 1 scores, yearly in-service training exam (ITE) scores, and passing the American Board of Internal Medicine certifying examination (ABIM-CE). The authors conducted a retrospective database review of internal medicine residents from the Medical College of Wisconsin from 2004 through 2012. Residents' USMLE Step 1, ITE, and ABIM-CE scores were extracted. Pearson rho, chi-square, and logistic regression were used to determine whether relationships existed between the scores and if Step 1 and ITE scores correlate with passing the ABIM-CE. There were 241 residents, who participated in 728 annual ITEs. There were Step 1 scores for 195 (81%) residents and ABIM-CE scores for 183 (76%). Step 1 and ABIM-CE scores had a modest correlation (rho: 0.59), as did ITE and ABIM-CE scores (rho: 0.48-0.67). Failing Step 1 or being in the bottom ITE quartile during any year of testing markedly increased likelihood of failing the boards (Step 1: relative risk [RR]: 2.4; 95% CI: 1.0-5.9; first-year residents' RR: 1.3; 95% CI: 1.0-1.6; second-year residents' RR: 1.3; 95% CI: 1.1-1.5; third-year residents' RR: 1.3; 95% CI: 1.1-1.5). USMLE Step 1 and ITE scores have a modest correlation with board scores. Failing Step 1 or scoring in the bottom quartile of the ITE increased the risk of failing the boards. What effective intervention, if any, program directors may use with at-risk residents is a question deserving further research.

Elderly patients are at increased risk for treatment failure in outpatient management of purulent skin infections.

PubMed

Haran, John P; Wilsterman, Eric; Zeoli, Tyler; Beaudoin, Francesca L; Tjia, Jennifer; Hibberd, Patricia L

2017-02-01

Current Infectious Disease Society of America (IDSA) guidelines for the management of purulent skin or soft tissue infections do not account for patient age in treatment recommendations. The study objective was to determine if age was associated with outpatient treatment failure for purulent skin infection after adjusting for IDSA treatment guidelines. We conducted a multicenter retrospective study of adult patients treated for a purulent skin infection and discharged home from four emergency departments between April and September 2014. Patients were followed for one month to assess for treatment failure (defined as need for a change in antibiotics, surgical intervention, or hospitalization). We used multivariable logistic regression to examine the role of patient age on treatment failure adjusting for demographic variables (gender, race), comorbidities and severity of infection. A total of 467 patients met inclusion criteria (mean age 37.9years [SD 14.0], 48.2% of whom were women). Overall, 12.4% failed initial therapy. Patients 65years and older (n=35) were almost 4 times more likely to fail initial ED therapy in follow-up compared with younger patients (adjusted Odds Ratio (OR) 3.87, 95% Confidence Interval (CI) 1.24-12.10). After adjustment, for every 10years of advancing age there was a 43% increased odds of failing initial treatment (OR 1.43 95% CI 1.09-1.88). Elderly patients with purulent skin infections, whose providers followed the 2014 IDSA guidelines, were more likely to fail initial treatment than younger patients. This study suggests that there is a need to re-evaluate treatment guidelines in elderly patients. Copyright © 2016 Elsevier Inc. All rights reserved.

Prevalence of, and risk factors for, presenting visual impairment: findings from a vision screening programme based on UK NSC guidance in a multi-ethnic population.

PubMed

Bruce, Alison; Santorelli, Gillian; Wright, John; Bradbury, John; Barrett, Brendan T; Bloj, Marina; Sheldon, Trevor A

2018-06-13

To determine presenting visual acuity levels and explore the factors associated with failing vision screening in a multi-ethnic population of UK children aged 4-5 years. Visual acuity (VA) using the logMAR Crowded Test was measured in 16,541 children in a population-based vision screening programme. Referral for cycloplegic examination was based on national recommendations (>0.20logMAR in one or both eyes). Presenting visual impairment (PVI) was defined as VA >0.3logMAR in the better eye. Multivariable logistic regression was used to assess the association of ethnicity, maternal, and early-life factors with failing vision screening and PVI in participants of the Born in Bradford birth cohort. In total, 2467/16,541 (15%) failed vision screening, 732 (4.4%) had PVI. Children of Pakistani (OR: 2.49; 95% CI: 1.74-3.60) and other ethnicities (OR: 2.00; 95% CI: 1.28-3.12) showed increased odds of PVI compared to white children. Children born to older mothers (OR: 1.63; 95% CI: 1.19-2.24) and of low birth weight (OR: 1.52; 95% CI: 1.00-2.34) also showed increased odds. Follow-up results were available for 1068 (43.3%) children, 993 (93%) were true positives; 932 (94%) of these had significant refractive error. Astigmatism (>1DC) (44%) was more common in children of Pakistani ethnicity and hypermetropia (>3.0DS) (27%) in white children (Fisher's exact, p < 0.001). A high prevalence of PVI is reported. Failing vision screening and PVI were highly associated with ethnicity. The positive predictive value of the vision screening programme was good, with only 7% of children followed up confirmed as false positives.

Home Health Agency Work Environments and Hospitalizations

PubMed Central

Flynn, Linda; Lake, Eileen T.; Aiken, Linda H.

2014-01-01

Background: An important goal of home health care is to assist patients to remain in community living arrangements. Yet home care often fails to prevent hospitalizations and to facilitate discharges to community living, thus putting patients at risk of additional health challenges and increasing care costs. Objectives: To determine the relationship between home health agency work environments and agency-level rates of acute hospitalization and discharges to community living. Methods and Design: Analysis of linked Center for Medicare and Medicaid Services Home Health Compare data and nurse survey data from 118 home health agencies. Robust regression models were used to estimate the effect of work environment ratings on between-agency variation in rates of acute hospitalization and community discharge. Results: Home health agencies with good work environments had lower rates of acute hospitalizations and higher rates of patient discharges to community living arrangements compared with home health agencies with poor work environments. Conclusion: Improved work environments in home health agencies hold promise for optimizing patient outcomes and reducing use of expensive hospital and institutional care. PMID:25215647

Meconium exposure and autism risk.

PubMed

Miller, K M; Xing, G; Walker, C K

2017-02-01

This study aims to determine whether fetal meconium passage is associated with autism. This retrospective birth cohort analysis of 9 945 896 children born in California 1991 to 2008 linked discharge diagnosis and procedure codes for prenatal stressors, meconium-stained amniotic fluid (MSAF) and meconium aspiration syndrome (MAS) with autism diagnoses for 47 277 children through 2012. We assessed the relative risk of autism by meconium status using logistic regression, adjusting for demographic and clinical features. Children exposed to meconium (MSAF and MAS) were more likely to be diagnosed with autism in comparison with unexposed children (0.60% and 0.52%, vs 0.47%, respectively). In adjusted analyses, there was a small increase in autism risk associated with MSAF exposure (adjusted relative risk (aRR) 1.18, 95% confidence interval (CI) 1.12 to 1.25), and a marginal association that failed to achieve significance between MAS and autism (aRR 1.08, 95% CI 0.98 to 1.20). Resuscitation of neonates with respiratory compromise from in utero meconium exposure may mitigate long-term neurodevelopmental damage.

Statin initiation by GPs in WA--a structured vignette study.

PubMed

Stafford, Leanne; Harmer, Nichola; Dhaliwal, Satvinder; Jiwa, Moyez

2009-09-01

Statins are recommended for all patients with known coronary heart disease. This pilot study investigated statin initiation by a Western Australian general practitioner cohort and the influence of prescriber and patient characteristics on prescribing. A structured vignette questionnaire was posted to members of the Fremantle GP Network. Respondents indicated their prescribing decisions for nine hypothetical patients who had recently suffered a myocardial infarction. Data analysis utilised logistic regression analyses and a generalised linear model with a logit link function. Fifty-five GPs responded (16.0% response rate). In over 20% of cases a statin was not prescribed. Male (OR 4.71; 95% CI: 1.24-17.87) and GPs with fewer years in practice (4.50; 1.21-16.77) were more likely to prescribe appropriately. Younger patients (2.21; 1.38-3.53), and those with diabetes (1.74; 1.09-2.76) or hypercholesterolaemia (4.81; 2.88-8.03) were more likely to receive therapy. Prescribing practices failed to comply with current guidelines in a significant number of cases. Further research to confirm these findings is warranted.

Modeling the germination kinetics of clostridium botulinum 56A spores as affected by temperature, pH, and sodium chloride.

PubMed

Chea, F P; Chen, Y; Montville, T J; Schaffner, D W

2000-08-01

The germination kinetics of proteolytic Clostridium botulinum 56A spores were modeled as a function of temperature (15, 22, 30 degrees C), pH (5.5, 6.0, 6.5), and sodium chloride (0.5, 2.0, 4.0%). Germination in brain heart infusion (BHI) broth was followed with phase-contrast microscopy. Data collected were used to develop the mathematical models. The germination kinetics expressed as cumulated fraction of germinated spores over time at each environmental condition were best described by an exponential distribution. Quadratic polynomial models were developed by regression analysis to describe the exponential parameter (time to 63% germination) (r2 = 0.982) and the germination extent (r2 = 0.867) as a function of temperature, pH, and sodium chloride. Validation experiments in BHI broth (pH: 5.75, 6.25; NaCl: 1.0, 3.0%; temperature: 18, 26 degrees C) confirmed that the model's predictions were within an acceptable range compared to the experimental results and were fail-safe in most cases.

Mediation Analysis with Multiple Mediators

PubMed Central

VanderWeele, T.J.; Vansteelandt, S.

2014-01-01

Recent advances in the causal inference literature on mediation have extended traditional approaches to direct and indirect effects to settings that allow for interactions and non-linearities. In this paper, these approaches from causal inference are further extended to settings in which multiple mediators may be of interest. Two analytic approaches, one based on regression and one based on weighting are proposed to estimate the effect mediated through multiple mediators and the effects through other pathways. The approaches proposed here accommodate exposure-mediator interactions and, to a certain extent, mediator-mediator interactions as well. The methods handle binary or continuous mediators and binary, continuous or count outcomes. When the mediators affect one another, the strategy of trying to assess direct and indirect effects one mediator at a time will in general fail; the approach given in this paper can still be used. A characterization is moreover given as to when the sum of the mediated effects for multiple mediators considered separately will be equal to the mediated effect of all of the mediators considered jointly. The approach proposed in this paper is robust to unmeasured common causes of two or more mediators. PMID:25580377

Mediation Analysis with Multiple Mediators.

PubMed

VanderWeele, T J; Vansteelandt, S

2014-01-01

Recent advances in the causal inference literature on mediation have extended traditional approaches to direct and indirect effects to settings that allow for interactions and non-linearities. In this paper, these approaches from causal inference are further extended to settings in which multiple mediators may be of interest. Two analytic approaches, one based on regression and one based on weighting are proposed to estimate the effect mediated through multiple mediators and the effects through other pathways. The approaches proposed here accommodate exposure-mediator interactions and, to a certain extent, mediator-mediator interactions as well. The methods handle binary or continuous mediators and binary, continuous or count outcomes. When the mediators affect one another, the strategy of trying to assess direct and indirect effects one mediator at a time will in general fail; the approach given in this paper can still be used. A characterization is moreover given as to when the sum of the mediated effects for multiple mediators considered separately will be equal to the mediated effect of all of the mediators considered jointly. The approach proposed in this paper is robust to unmeasured common causes of two or more mediators.

Impact of increasing heat waves on U.S. ozone episodes in the 2050s: Results from a multimodel analysis using extreme value theory

NASA Astrophysics Data System (ADS)

Shen, L.; Mickley, L. J.; Gilleland, E.

2016-04-01

We develop a statistical model using extreme value theory to estimate the 2000-2050 changes in ozone episodes across the United States. We model the relationships between daily maximum temperature (Tmax) and maximum daily 8 h average (MDA8) ozone in May-September over 2003-2012 using a Point Process (PP) model. At ~20% of the sites, a marked decrease in the ozone-temperature slope occurs at high temperatures, defined as ozone suppression. The PP model sometimes fails to capture ozone-Tmax relationships, so we refit the ozone-Tmax slope using logistic regression and a generalized Pareto distribution model. We then apply the resulting hybrid-extreme value theory model to projections of Tmax from an ensemble of downscaled climate models. Assuming constant anthropogenic emissions at the present level, we find an average increase of 2.3 d a-1 in ozone episodes (>75 ppbv) across the United States by the 2050s, with a change of +3-9 d a-1 at many sites.

Determinants of access to experimental antiretroviral drugs in an Italian cohort of patients with HIV: a multilevel analysis.

PubMed

Girardi, Enrico; Scognamiglio, Paola; Angeletti, Claudio; Gori, Andrea; Buonfrate, Dora; Arlotti, Massimo; Mazzarello, Giovanni; Castagna, Antonella; Andreoni, Massimo; d'Arminio Monforte, Antonella; Antinori, Andrea; Ippolito, Giuseppe

2012-02-15

Identification of the determinants of access to investigational drugs is important to promote equity and scientific validity in clinical research. We aimed to analyze factors associated with the use of experimental antiretrovirals in Italy. We studied participants in the Italian Cohort of Antiretroviral-Naive Patients (ICoNA). All patients 18 years or older who had started cART (≥ 3 drugs including at least two NRTI) after their enrolment and during 1997-2007 were included in this analysis. We performed a random effect logistic regression analysis to take into account clustering observations within clinical units. The outcome variable was the use of an experimental antiretroviral, defined as an antiretroviral started before commercial availability, in any episode of therapy initiation/change. Use of an experimental antiretroviral obtained through a clinical trial or an expanded access program (EAP) was also analyzed separately. A total of 9,441 episodes of therapy initiation/change were analyzed in 3,752 patients. 392 episodes (360 patients) involved an experimental antiretroviral. In multivariable analysis, factors associated with the overall use of experimental antiretrovirals were: number of experienced drugs (≥ 8 drugs versus "naive": adjusted odds ratio [AOR] = 3.71) or failed antiretrovirals(3-4 drugs and ≥ 5 drugs versus 0-2 drugs: AOR = 1.42 and 2.38 respectively); calendar year (AOR = 0.80 per year) and plasma HIV-RNA copies/ml at therapy change (≥ 4 log versus < 2 log: AOR = 1.55). The probability of taking an experimental antiretroviral through a trial was significantly lower for patients suffering from liver co-morbidity(AOR = 0.65) and for those who experienced 3-4 drugs (vs naive) (AOR = 0.55), while it increased for multi-treated patients(AOR = 2.60). The probability to start an experimental antiretroviral trough an EAP progressively increased with the increasing number of experienced and of failed drugs and also increased for patients with liver co-morbidity (AOR = 1.44; p = 0.053). and for male homosexuals (vs heterosexuals: AOR = 1.67). Variability of the random effect associated to clinical units was statistically significant (p < 0.001) although no association was found with specific characteristics of clinical unit examined. Among patients with HIV infection in Italy, access to experimental antiretrovirals seems to be influenced mainly by exhaustion of treatment options and not by socio-demographic factors.

[A SAS marco program for batch processing of univariate Cox regression analysis for great database].

PubMed

Yang, Rendong; Xiong, Jie; Peng, Yangqin; Peng, Xiaoning; Zeng, Xiaomin

2015-02-01

To realize batch processing of univariate Cox regression analysis for great database by SAS marco program. We wrote a SAS macro program, which can filter, integrate, and export P values to Excel by SAS9.2. The program was used for screening survival correlated RNA molecules of ovarian cancer. A SAS marco program could finish the batch processing of univariate Cox regression analysis, the selection and export of the results. The SAS macro program has potential applications in reducing the workload of statistical analysis and providing a basis for batch processing of univariate Cox regression analysis.

Exact Analysis of Squared Cross-Validity Coefficient in Predictive Regression Models

ERIC Educational Resources Information Center

Shieh, Gwowen

2009-01-01

In regression analysis, the notion of population validity is of theoretical interest for describing the usefulness of the underlying regression model, whereas the presumably more important concept of population cross-validity represents the predictive effectiveness for the regression equation in future research. It appears that the inference…

Selective principal component regression analysis of fluorescence hyperspectral image to assess aflatoxin contamination in corn

USDA-ARS?s Scientific Manuscript database

Selective principal component regression analysis (SPCR) uses a subset of the original image bands for principal component transformation and regression. For optimal band selection before the transformation, this paper used genetic algorithms (GA). In this case, the GA process used the regression co...

Difficult Airway Characteristics Associated with First-Attempt Failure at Intubation Using Video Laryngoscopy in the Intensive Care Unit.

PubMed

Joshi, Raj; Hypes, Cameron D; Greenberg, Jeremy; Snyder, Linda; Malo, Josh; Bloom, John W; Chopra, Harsharon; Sakles, John C; Mosier, Jarrod M

2017-03-01

Video laryngoscopy has overcome the need to align the anatomic axes to obtain a view of the glottic opening to place a tracheal tube. However, despite this advantage, a large number of attempts are unsuccessful. There are no existing data on anatomic characteristics in critically ill patients associated with a failed first attempt at laryngoscopy when using video laryngoscopy. To identify characteristics associated with first-attempt failure at intubation when using video laryngoscopy in the intensive care unit (ICU). This is an observational study of 906 consecutive patients intubated in the ICU with a video laryngoscope between January 2012 and January 2016 in a single-center academic medical ICU. After each intubation, the operator completed a data collection form, which included information on difficult airway characteristics, device used, and outcome of each attempt. Multivariable regression models were constructed to determine the difficult airway characteristics associated with a failed first attempt at intubation. There were no significant differences in sex, age, reason for intubation, or device used between first-attempt failures and first-attempt successes. First-attempt successes more commonly reported no difficult airway characteristics were present (23.9%; 95% confidence interval [CI], 20.7-27.0% vs. 13.3%; 95% CI, 8.0-18.8%). In logistic regression analysis of the entire 906-patient database, blood in the airway (odds ratio [OR], 2.63; 95% CI, 1.64-4.20), airway edema (OR, 2.85; 95% CI, 1.48-5.45), and obesity (OR, 1.59; 95% CI, 1.08-2.32) were significantly associated with first-attempt failure. Data collection on limited mouth opening and secretions began after the first 133 intubations, and we fit a second logistic model to examine cases in which these additional difficult airway characteristics were collected. In this subset (n = 773), the presence of blood (OR, 2.73; 95% CI, 1.60-4.64), cervical immobility (OR, 3.34; 95% CI, 1.28-8.72), and airway edema (OR, 3.10; 95% CI, 1.42-6.70) were associated with first-attempt failure. In this single-center study, presence of blood in the airway, airway edema, cervical immobility, and obesity are associated with higher odds of first-attempt failure, when intubation was performed with video laryngoscopy in an ICU.

First regulatory inspections measuring adherence to Good Pharmacy Practices in the public sector in Uganda: a cross-sectional comparison of performance between supervised and unsupervised facilities.

PubMed

Trap, Birna; Kikule, Kate; Vialle-Valentin, Catherine; Musoke, Richard; Lajul, Grace Otto; Hoppenworth, Kim; Konradsen, Dorthe

2016-01-01

Since its inception, the Uganda National Drug Authority (NDA) has regularly inspected private sector pharmacies to monitor adherence to Good Pharmacy Practices (GPP). This study reports findings from the first public facility inspections following an intervention (SPARS: Supervision, Performance Assessment, and Recognition Strategy) to build GPP and medicines management capacity in the public sector. The study includes 455 public facilities: 417 facilities were inspected after at least four SPARS visits by trained managerial district staff (SPARS group), 38 before any exposure to SPARS. NDA inspectors measured 10 critical, 20 major, and 37 minor GPP indicators in every facility and only accredited facilities that passed all 10 critical and failed no more than 7 major indicators. Lack of compliance for a given indicator was defined as less than 75 % facilities passing that indicator. We assessed factors associated with certification using logistic regression analysis and compared number of failed indicators between the SPARS and comparative groups using two sample t-tests with equal or unequal variance. 57.4 % of inspected facilities obtained GPP certification: 57.1 % in the SPARS and 60.5 % in the comparative group (Adj. OR = 0.91, 95 % CI 0.45-1.85, p = 0.802). Overall, facilities failed an average of 10 indicators. SPARS facilities performed better than comparative facilities (9 (SD 6.1) vs. 13 (SD 7.7) failed indicators respectively; p = 0.017), and SPARS supported facilities scored better on indicators covered by SPARS. For all indicators but one minor, performance in the SPARS group was equal to or significantly better than in unsupervised facilities. Within the SPARS (intervention) group, certified facilities had < 75 % compliance on 7 indicators (all minor), and uncertified facilities on 19 (4 critical, 2 major, and 13 minor) indicators. Half of the Ugandan population obtains medicines from the public sector. Yet, we found only 3/5 of inspected public health facilities meet GPP standards. SPARS facilities tended to perform better than unsupervised facilities, substantiating the value of supporting supervision interventions in GPP areas that need strengthening. None compliant indicators can be improved through practices and behavioral changes; some require infrastructure investments. We conclude that regular NDA inspections of public sector pharmacies in conjunction with interventions to improve GPP adherence can revolutionize patient care in Uganda.

Primary vs Conversion Total Hip Arthroplasty: A Cost Analysis

PubMed Central

Chin, Garwin; Wright, David J.; Snir, Nimrod; Schwarzkopf, Ran

2018-01-01

Introduction Increasing hip fracture incidence in the United States is leading to higher occurrences of conversion total hip arthroplasty (THA) for failed surgical treatment of the hip. In spite of studies showing higher complication rates in conversion THA, the Centers for Medicare and Medicaid services currently bundles conversion and primary THA under the same diagnosis-related group. We examined the cost of treatment of conversion THA compared with primary THA. Our hypothesis is that conversion THA will have higher cost and resource use than primary THA. Methods Fifty-one consecutive conversion THA patients (Current Procedure Terminology code 27132) and 105 matched primary THA patients (Current Procedure Terminology code 27130) were included in this study. The natural log-transformed costs for conversion and primary THA were compared using regression analysis. Age, gender, body mass index, American Society of Anesthesiologist, Charlson comorbidity score, and smoker status were controlled in the analysis. Conversion THA subgroups formed based on etiology were compared using analysis of variance analysis. Results Conversion and primary THAs were determined to be significantly different (P < .05) and greater in the following costs: hospital operating direct cost (29.2% greater), hospital operating total cost (28.8% greater), direct hospital cost (24.7% greater), and total hospital cost (26.4% greater). Conclusions Based on greater hospital operating direct cost, hospital operating total cost, direct hospital cost, and total hospital cost, conversion THA has significantly greater cost and resource use than primary THA. In order to prevent disincentives for treating these complex surgical patients, reclassification of conversion THA is needed, as they do not fit together with primary THA. PMID:26387923

Time Spent Walking and Risk of Diabetes in Japanese Adults: The Japan Public Health Center-Based Prospective Diabetes Study.

PubMed

Kabeya, Yusuke; Goto, Atsushi; Kato, Masayuki; Matsushita, Yumi; Takahashi, Yoshihiko; Isogawa, Akihiro; Inoue, Manami; Mizoue, Tetsuya; Tsugane, Shoichiro; Kadowaki, Takashi; Noda, Mitsuhiko

2016-01-01

The association between time spent walking and risk of diabetes was investigated in a Japanese population-based cohort. Data from the Japan Public Health Center-based Prospective Diabetes cohort were analyzed. The surveys of diabetes were performed at baseline and at the 5-year follow-up. Time spent walking per day was assessed using a self-reported questionnaire (<30 minutes, 30 minutes to <1 hour, 1 to <2 hours, or ≥2 hours). A cross-sectional analysis was performed among 26 488 adults in the baseline survey. Logistic regression was used to examine the association between time spent walking and the presence of unrecognized diabetes. We then performed a longitudinal analysis that was restricted to 11 101 non-diabetic adults who participated in both the baseline and 5-year surveys. The association between time spent walking and the incidence of diabetes during the 5 years was examined. In the cross-sectional analysis, 1058 participants had unrecognized diabetes. Those with time spent walking of <30 minutes per day had increased odds of having diabetes in relation to those with time spent walking of ≥2 hours (adjusted odds ratio [OR] 1.23; 95% CI, 1.02-1.48). In the longitudinal analysis, 612 participants developed diabetes during the 5 years of follow-up. However, a significant association between time spent walking and the incidence of diabetes was not observed. Increased risk of diabetes was implied in those with time spent walking of <30 minutes per day, although the longitudinal analysis failed to show a significant result.

Reliability and sensitivity analysis of a system with multiple unreliable service stations and standby switching failures

NASA Astrophysics Data System (ADS)

Ke, Jyh-Bin; Lee, Wen-Chiung; Wang, Kuo-Hsiung

2007-07-01

This paper presents the reliability and sensitivity analysis of a system with M primary units, W warm standby units, and R unreliable service stations where warm standby units switching to the primary state might fail. Failure times of primary and warm standby units are assumed to have exponential distributions, and service times of the failed units are exponentially distributed. In addition, breakdown times and repair times of the service stations also follow exponential distributions. Expressions for system reliability, RY(t), and mean time to system failure, MTTF are derived. Sensitivity analysis, relative sensitivity analysis of the system reliability and the mean time to failure, with respect to system parameters are also investigated.

Cost-utility analysis of competing treatment strategies for drug-resistant epilepsy in children with Tuberous Sclerosis Complex.

PubMed

Fallah, Aria; Weil, Alexander G; Wang, Shelly; Lewis, Evan; Baca, Christine B; Mathern, Gary W

2016-10-01

The management of drug-resistant epilepsy in children with Tuberous Sclerosis Complex (TSC) is challenging because of the multitude of treatment options, wide range of associated costs, and uncertainty of seizure outcomes. The most cost-effective approach for children whose epilepsy has failed to improve with first-line medical therapy is uncertain. A review of MEDLINE from 1990 to 2015 was conducted. A cost-utility analysis, from a third-party payer perspective, was performed for children with drug-resistant epilepsy that had failed to improve with 2 antiseizure drugs (ASDs) and that was amenable to resective epilepsy surgery, across a time-horizon of 5years. Four strategies were included: (1) resective epilepsy surgery, (2) vagus nerve stimulator (VNS) implantation, (3) ketogenic diet, and (4) addition of a third ASD (specifically, carbamazepine). The incremental cost per quality-adjusted life year (QALY) gained was analyzed. Given a willingness-to-pay (WTP) of $100,000 per QALY, the addition of a third ASD ($6600 for a gain of 4.14 QALYs) was the most cost-effective treatment strategy. In a secondary analysis, if the child whose epilepsy had failed to improve with 3 ASDs, ketogenic diet, addition of a fourth ASD, and resective epilepsy surgery were incrementally cost-effective treatment strategies. Vagus nerve stimulator implantation was more expensive yet less effective than alternative strategies and should not be prioritized. The addition of a third ASD is a universally cost-effective treatment option in the management of children with drug-resistant epilepsy that has failed to improve with 2 ASDs. For children whose epilepsy has failed to improve with 3 ASDs, the most cost-effective treatment depends on the health-care resources available reflected by the WTP. Copyright © 2016 Elsevier Inc. All rights reserved.

Study of a fail-safe abort system for an actively cooled hypersonic aircraft: Computer program documentation

NASA Technical Reports Server (NTRS)

Haas, L. A., Sr.

1976-01-01

The Fail-Safe Abort System TEMPerature Analysis Program, (FASTEMP), user's manual is presented. This program was used to analyze fail-safe abort systems for an actively cooled hypersonic aircraft. FASTEMP analyzes the steady state or transient temperature response of a thermal model defined in rectangular, cylindrical, conical and/or spherical coordinate system. FASTEMP provides the user with a large selection of subroutines for heat transfer calculations. The various modes of heat transfer available from these subroutines are: heat storage, conduction, radiation, heat addition or generation, convection, and fluid flow.

The reliability of the pass/fail decision for assessments comprised of multiple components.

PubMed

Möltner, Andreas; Tımbıl, Sevgi; Jünger, Jana

2015-01-01

The decision having the most serious consequences for a student taking an assessment is the one to pass or fail that student. For this reason, the reliability of the pass/fail decision must be determined for high quality assessments, just as the measurement reliability of the point values. Assessments in a particular subject (graded course credit) are often composed of multiple components that must be passed independently of each other. When "conjunctively" combining separate pass/fail decisions, as with other complex decision rules for passing, adequate methods of analysis are necessary for estimating the accuracy and consistency of these classifications. To date, very few papers have addressed this issue; a generally applicable procedure was published by Douglas and Mislevy in 2010. Using the example of an assessment comprised of several parts that must be passed separately, this study analyzes the reliability underlying the decision to pass or fail students and discusses the impact of an improved method for identifying those who do not fulfill the minimum requirements. The accuracy and consistency of the decision to pass or fail an examinee in the subject cluster Internal Medicine/General Medicine/Clinical Chemistry at the University of Heidelberg's Faculty of Medicine was investigated. This cluster requires students to separately pass three components (two written exams and an OSCE), whereby students may reattempt to pass each component twice. Our analysis was carried out using the method described by Douglas and Mislevy. Frequently, when complex logical connections exist between the individual pass/fail decisions in the case of low failure rates, only a very low reliability for the overall decision to grant graded course credit can be achieved, even if high reliabilities exist for the various components. For the example analyzed here, the classification accuracy and consistency when conjunctively combining the three individual parts is relatively low with κ=0.49 or κ=0.47, despite the good reliability of over 0.75 for each of the three components. The option to repeat each component twice leads to a situation in which only about half of the candidates who do not satisfy the minimum requirements would fail the overall assessment, while the other half is able to continue their studies despite having deficient knowledge and skills. The method put forth by Douglas and Mislevy allows the analysis of the decision accuracy and consistency for complex combinations of scores from different components. Even in the case of highly reliable components, it is not necessarily so that a reliable pass/fail decision has been reached - for instance in the case of low failure rates. Assessments must be administered with the explicit goal of identifying examinees that do not fulfill the minimum requirements.

The reliability of the pass/fail decision for assessments comprised of multiple components

PubMed Central

Möltner, Andreas; Tımbıl, Sevgi; Jünger, Jana

2015-01-01

Objective: The decision having the most serious consequences for a student taking an assessment is the one to pass or fail that student. For this reason, the reliability of the pass/fail decision must be determined for high quality assessments, just as the measurement reliability of the point values. Assessments in a particular subject (graded course credit) are often composed of multiple components that must be passed independently of each other. When “conjunctively” combining separate pass/fail decisions, as with other complex decision rules for passing, adequate methods of analysis are necessary for estimating the accuracy and consistency of these classifications. To date, very few papers have addressed this issue; a generally applicable procedure was published by Douglas and Mislevy in 2010. Using the example of an assessment comprised of several parts that must be passed separately, this study analyzes the reliability underlying the decision to pass or fail students and discusses the impact of an improved method for identifying those who do not fulfill the minimum requirements. Method: The accuracy and consistency of the decision to pass or fail an examinee in the subject cluster Internal Medicine/General Medicine/Clinical Chemistry at the University of Heidelberg’s Faculty of Medicine was investigated. This cluster requires students to separately pass three components (two written exams and an OSCE), whereby students may reattempt to pass each component twice. Our analysis was carried out using the method described by Douglas and Mislevy. Results: Frequently, when complex logical connections exist between the individual pass/fail decisions in the case of low failure rates, only a very low reliability for the overall decision to grant graded course credit can be achieved, even if high reliabilities exist for the various components. For the example analyzed here, the classification accuracy and consistency when conjunctively combining the three individual parts is relatively low with κ=0.49 or κ=0.47, despite the good reliability of over 0.75 for each of the three components. The option to repeat each component twice leads to a situation in which only about half of the candidates who do not satisfy the minimum requirements would fail the overall assessment, while the other half is able to continue their studies despite having deficient knowledge and skills. Conclusion: The method put forth by Douglas and Mislevy allows the analysis of the decision accuracy and consistency for complex combinations of scores from different components. Even in the case of highly reliable components, it is not necessarily so that a reliable pass/fail decision has been reached – for instance in the case of low failure rates. Assessments must be administered with the explicit goal of identifying examinees that do not fulfill the minimum requirements. PMID:26483855

Bentamapimod (JNK Inhibitor AS602801) Induces Regression of Endometriotic Lesions in Animal Models.

PubMed

Palmer, Stephen S; Altan, Melis; Denis, Deborah; Tos, Enrico Gillio; Gotteland, Jean-Pierre; Osteen, Kevin G; Bruner-Tran, Kaylon L; Nataraja, Selvaraj G

2016-01-01

Endometriosis is an estrogen (ER)-dependent gynecological disease caused by the growth of endometrial tissue at extrauterine sites. Current endocrine therapies address the estrogenic aspect of disease and offer some relief from pain but are associated with significant side effects. Immune dysfunction is also widely believed to be an underlying contributor to the pathogenesis of this disease. This study evaluated an inhibitor of c-Jun N-terminal kinase, bentamapimod (AS602801), which interrupts immune pathways, in 2 rodent endometriosis models. Treatment of nude mice bearing xenografts biopsied from women with endometriosis (BWE) with 30 mg/kg AS602801 caused 29% regression of lesion. Medroxyprogesterone acetate (MPA) or progesterone (PR) alone did not cause regression of BWE lesions, but combining 10 mg/kg AS602801 with MPA caused 38% lesion regression. In human endometrial organ cultures (from healthy women), treatment with AS602801 or MPA reduced matrix metalloproteinase-3 (MMP-3) release into culture medium. In organ cultures established with BWE, PR or MPA failed to inhibit MMP-3 secretion, whereas AS602801 alone or MPA + AS602801 suppressed MMP-3 production. In an autologous rat endometriosis model, AS602801 caused 48% regression of lesions compared to GnRH antagonist Antide (84%). AS602801 reduced inflammatory cytokines in endometriotic lesions, while levels of cytokines in ipsilateral horns were unaffected. Furthermore, AS602801 enhanced natural killer cell activity, without apparent negative effects on uterus. These results indicate that bentamapimod induced regression of endometriotic lesions in endometriosis rodent animal models without suppressing ER action. c-Jun N-terminal kinase inhibition mediated a comprehensive reduction in cytokine secretion and moreover was able to overcome PR resistance. © The Author(s) 2015.

Outcomes of Term Induction in Trial of Labor After Cesarean Delivery: Analysis of a Modern Obstetric Cohort.

PubMed

Lappen, Justin R; Hackney, David N; Bailit, Jennifer L

2015-07-01

To evaluate outcomes of induction of labor, compared with expectant management, in women attempting trial of labor after cesarean delivery (TOLAC) in a large obstetric cohort. We performed a secondary analysis of data from the Consortium on Safe Labor that included women with term (37 weeks of gestation or greater) singleton gestations and a history of one prior cesarean delivery who attempted TOLAC. Induction of labor was compared with expectant management by week of gestation from 37 to 40 weeks in both high- and low-risk cohorts. The primary outcome was failed TOLAC. Secondary outcomes included composite maternal morbidity (hysterectomy, transfusion, intensive care unit (ICU) transfer, venous thromboembolism, death), composite neonatal morbidity (5-minute Apgar score less than 5, cord pH less than 7.0, asphyxia, hypoxic ischemic encephalopathy, neonatal death), and neonatal ICU admission. Multivariate logistic regression was performed with adjustment for confounding factors. We identified 6,033 women attempting TOLAC of whom 1,626 (27.0%) underwent induction of labor and 4,407 (73.0%) did not. Compared with expectant management, induction was associated with an increased risk of failed TOLAC at 37-39 weeks of gestation but not at 40 weeks of gestation (37 weeks of gestation, 48.5% compared with 34.3%, adjusted odds ratio [OR] 1.53, 95% confidence interval [CI] 1.02-2.28]; 38 weeks of gestation, 47.0% compared with 33.0%, adjusted OR 1.74, 95% CI 1.29-2.34; 39 weeks of gestation, 45.6% compared with 29.8%, adjusted OR 2.16, 95% CI 1.76-2.67; 40 weeks of gestation, 37.9% compared with 29.4%, adjusted OR 1.21, 95% CI 0.90-1.66). Induction was associated with an increased risk of composite maternal morbidity at 39 weeks of gestation (adjusted OR 1.87, 95% CI 1.22-2.87) and neonatal ICU admission at 37 weeks of gestation (adjusted OR 2.51, 95% CI 1.62-3.90). Induction was not associated with an increased risk of neonatal morbidity. Induction of labor in women with one prior cesarean delivery, compared with expectant management, is associated with an increased risk of failed TOLAC. Apart from small increases in maternal morbidity at 39 weeks and neonatal ICU admission at 37 weeks of gestation, induction is not associated with an increased risk of severe maternal or neonatal morbidity. II.

Development of a User Interface for a Regression Analysis Software Tool

NASA Technical Reports Server (NTRS)

Ulbrich, Norbert Manfred; Volden, Thomas R.

2010-01-01

An easy-to -use user interface was implemented in a highly automated regression analysis tool. The user interface was developed from the start to run on computers that use the Windows, Macintosh, Linux, or UNIX operating system. Many user interface features were specifically designed such that a novice or inexperienced user can apply the regression analysis tool with confidence. Therefore, the user interface s design minimizes interactive input from the user. In addition, reasonable default combinations are assigned to those analysis settings that influence the outcome of the regression analysis. These default combinations will lead to a successful regression analysis result for most experimental data sets. The user interface comes in two versions. The text user interface version is used for the ongoing development of the regression analysis tool. The official release of the regression analysis tool, on the other hand, has a graphical user interface that is more efficient to use. This graphical user interface displays all input file names, output file names, and analysis settings for a specific software application mode on a single screen which makes it easier to generate reliable analysis results and to perform input parameter studies. An object-oriented approach was used for the development of the graphical user interface. This choice keeps future software maintenance costs to a reasonable limit. Examples of both the text user interface and graphical user interface are discussed in order to illustrate the user interface s overall design approach.

Regression Analysis and the Sociological Imagination

ERIC Educational Resources Information Center

De Maio, Fernando

2014-01-01

Regression analysis is an important aspect of most introductory statistics courses in sociology but is often presented in contexts divorced from the central concerns that bring students into the discipline. Consequently, we present five lesson ideas that emerge from a regression analysis of income inequality and mortality in the USA and Canada.

The annealing helicase and branch migration activities of Drosophila HARP.

PubMed

Kassavetis, George A; Kadonaga, James T

2014-01-01

HARP (SMARCAL1, MARCAL1) is an annealing helicase that functions in the repair and restart of damaged DNA replication forks through its DNA branch migration and replication fork regression activities. HARP is conserved among metazoans. HARP from invertebrates differs by the absence of one of the two HARP-specific domain repeats found in vertebrates. The annealing helicase and branch migration activity of invertebrate HARP has not been documented. We found that HARP from Drosophila melanogaster retains the annealing helicase activity of human HARP, the ability to disrupt D-loops and to branch migrate Holliday junctions, but fails to regress model DNA replication fork structures. A comparison of human and Drosophila HARP on additional substrates revealed that both HARPs are competent in branch migrating a bidirectional replication bubble composed of either DNA:DNA or RNA:DNA hybrid. Human, but not Drosophila, HARP is also capable of regressing a replication fork structure containing a highly stable poly rG:dC hybrid. Persistent RNA:DNA hybrids in vivo can lead to replication fork arrest and genome instability. The ability of HARP to strand transfer hybrids may signify a hybrid removal function for this enzyme, in vivo.

Genetic prediction of type 2 diabetes using deep neural network.

PubMed

Kim, J; Kim, J; Kwak, M J; Bajaj, M

2018-04-01

Type 2 diabetes (T2DM) has strong heritability but genetic models to explain heritability have been challenging. We tested deep neural network (DNN) to predict T2DM using the nested case-control study of Nurses' Health Study (3326 females, 45.6% T2DM) and Health Professionals Follow-up Study (2502 males, 46.5% T2DM). We selected 96, 214, 399, and 678 single-nucleotide polymorphism (SNPs) through Fisher's exact test and L1-penalized logistic regression. We split each dataset randomly in 4:1 to train prediction models and test their performance. DNN and logistic regressions showed better area under the curve (AUC) of ROC curves than the clinical model when 399 or more SNPs included. DNN was superior than logistic regressions in AUC with 399 or more SNPs in male and 678 SNPs in female. Addition of clinical factors consistently increased AUC of DNN but failed to improve logistic regressions with 214 or more SNPs. In conclusion, we show that DNN can be a versatile tool to predict T2DM incorporating large numbers of SNPs and clinical information. Limitations include a relatively small number of the subjects mostly of European ethnicity. Further studies are warranted to confirm and improve performance of genetic prediction models using DNN in different ethnic groups. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

A Nomogram to Predict Anastomotic Leakage in Open Rectal Surgery-Hope or Hype?

PubMed

Klose, Johannes; Tarantino, Ignazio; von Fournier, Armin; Stowitzki, Moritz J; Kulu, Yakup; Bruckner, Thomas; Volz, Claudia; Schmidt, Thomas; Schneider, Martin; Büchler, Markus W; Ulrich, Alexis

2018-05-18

Anastomotic leakage is the most dreaded complication after rectal resection and total mesorectal excision, leading to increased morbidity and mortality. Formation of a diverting ileostomy is generally performed to protect anastomotic healing. Identification of variables predicting anastomotic leakage might help to select patients who are under increased risk for the development of anastomotic leakage prior to surgery. The objective of this study was to assess the applicability of a nomogram as prognostic model for the occurrence of anastomotic leakage after rectal resection in a cohort of rectal cancer patients. Nine hundred seventy-two consecutive patients who underwent surgery for rectal cancer were retrospectively analyzed. Univariate and multivariable Cox regression analyses were used to determine independent risk factors associated with anastomotic leakage. Receiver operating characteristics (ROC) curve analysis was performed to calculate the sensitivity, specificity, and overall model correctness of a recently published nomogram and an adopted risk score based on the variables identified in this study as a predictive model. Male sex (p = 0.042), obesity (p = 0.017), smoking (p = 0.012), postoperative bleeding (p = 0.024), and total protein level ≤ 5.6 g/dl (p = 0.007) were identified as independent risk factors for anastomotic leakage. The investigated nomogram and the adopted risk score failed to reach relevant areas under the ROC curve greater than 0.700 for the prediction of anastomotic leakage. The proposed nomogram and the adopted risk score failed to reliably predict the occurrence of anastomotic leakage after rectal resection. Risk scores as prognostic models for the prediction of anastomotic leakage, independently of the study population, still need to be identified.

Effectiveness of the Baby Friendly Community Initiative in Italy: a non-randomised controlled study

PubMed Central

Cattaneo, Adriano; Bettinelli, Maria Enrica; Chapin, Elise; Macaluso, Anna; Córdova do Espírito Santo, Lílian; Murante, Anna Maria; Montico, Marcella

2016-01-01

Objective To assess the effectiveness of the Baby Friendly Community Initiative (BFCI) on exclusive breast feeding at 6 months. Design Controlled, non-randomised trial. Setting 18 Local Health Authorities in 9 regions of Italy. Participants 5094 mother/infant dyads in 3 cohorts were followed up to 12 months after birth in 3 rounds of data collection: at baseline, after implementation of the intervention in the early intervention group and after implementation in the late intervention group. 689 (14%) dyads did not complete the study. Intervention Implementation of the 7 steps of the BFCI. Main outcome measures The rate of exclusive breast feeding at 6 months was the primary outcome; breast feeding at discharge, 3 and 12 months was also measured. Results The crude rates of exclusive breast feeding at discharge, 3 and 6 months, and of any breast feeding at 6 and 12 months increased at each round of data collection after baseline in the early and late intervention groups. At the end of the project, 10% of infants were exclusively breast fed at 6 months and 38% were continuing to breast feed at 12 months. However, the comparison by adjusted rates and logistic regression failed to show statistically significant differences between groups and rounds of data collection in the intention-to-treat analysis, as well as when compliance with the intervention and training coverage was taken into account. Conclusions The study failed to demonstrate an effect of the BFCI on the rates of breast feeding. This may be due, among other factors, to the time needed to observe an effect on breast feeding following this complex intervention. PMID:27154476

Renal function preservation with pioglitazone or with basal insulin as an add-on therapy for patients with type 2 diabetes mellitus.

PubMed

Chang, Yu-Hung; Hwu, Der-Wei; Chang, Dao-Ming; An, Ling-Wang; Hsieh, Chang-Hsun; Lee, Yau-Jiunn

2017-06-01

Clinical outcome may differ owing to the distinct pharmacological characteristics of insulin sensitizers and insulin. This study was performed to compare the metabolic and renal function changes with add-on pioglitazone treatment versus basal insulin in patients with type 2 diabetes mellitus (DM) in whom sulfonylurea and metformin regimens failed. Patients who were consecutively managed in the diabetes comprehensive program with add-on pioglitazone or detemir/glargine treatment for at least 2 years following sulfonylurea and metformin treatment failure were included. A total of 1002 patients were enrolled (pioglitazone: 559, detemir: 264, glargine: 179). After propensity score matching, there were 105 patients with matchable baseline characteristics in each group. After a mean of 3.5 years of follow-up, the pioglitazone group showed a greater HbA1c reduction than the detemir group and the glargine group. Despite patients in all three groups exhibiting significant body weight gain, those in the pioglitazone group and the glargine group showed greater body weight increases than the patients in the detemir group (2.1, 1.6 and 0.8 kg, respectively, p < 0.05). Interestingly, Cox regression analysis indicated that patients under detemir or glargine treatment had a higher probability of CKD progression as compared with the pioglitazone group, with hazard ratios of 2.63 (95% CI 1.79-3.88) and 3.13 (95% CI 2.01-4.87), respectively. Our study first showed that treatment with both pioglitazone and basal insulin improved glycemic control, while only pioglitazone treatment was observed to be advantageous in terms of preserving renal function when used as an add-on therapy for patients with type 2 DM in whom sulfonylurea and metformin regimens failed.

Pneumatic balloon dilation in pediatric achalasia: efficacy and factors predicting outcome at a single tertiary pediatric gastroenterology center.

PubMed

Di Nardo, Giovanni; Rossi, Paolo; Oliva, Salvatore; Aloi, Marina; Cozzi, Denis A; Frediani, Simone; Redler, Adriano; Mallardo, Saverio; Ferrari, Federica; Cucchiara, Salvatore

2012-11-01

The use of pneumatic dilation (PD) is well established in adults with achalasia; however, it is less commonly used in children. To evaluate the efficacy of PD in pediatric achalasia and to define predictive factors for its treatment failure. Single-center, prospective cohort study. Academic tertiary referral center. Twenty-four patients with achalasia were enrolled from January 2004 to November 2009 and were followed for a median of 6 years. PD was performed with the patients under general anesthesia. Efficacy and safety of PD. Follow-up was performed by using the Eckardt score, barium swallow contrast studies, and esophageal manometry at baseline; 1, 3, and 6 months after dilation; and every year thereafter. A Cox regression model was used to identify independent predictors of failure after the first PD. The PD success rate was 67%. In 8 patients, the first PD failed, but the parents of one patient refused a second PD and requested surgery. Of the 7 patients who underwent repeated treatment, the second PD failed in 3 (43%). Overall, only 3 of the 24 patients underwent surgery (overall success rate after a maximum of 3 PDs was 87%). Multivariate analysis showed that only older age was independently associated with a higher probability of the procedure success (hazard ratio [HR] 0.66; 95% CI, 0.45-0.97). Small sample size, single-center study. PD is a safe and effective technique in the management of pediatric achalasia. Young age is an independent negative predictive factor for successful clinical outcome. Copyright © 2012 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.

Mortality after Renal Allograft Failure and Return to Dialysis.

PubMed

Brar, Amarpali; Markell, Mariana; Stefanov, Dimitre G; Timpo, Edem; Jindal, Rahul M; Nee, Robert; Sumrani, Nabil; John, Devon; Tedla, Fasika; Salifu, Moro O

2017-01-01

The outcomes of patients who fail their kidney transplant and return to dialysis (RTD) has not been investigated in a nationally representative sample. We hypothesized that variations in management of transplant chronic kidney disease stage 5 leading to kidney allograft failure (KAF) and RTD, such as access, nutrition, timing of dialysis, and anemia management predict long-term survival. We used an incident cohort of patients from the United States Renal Data System who initiated hemodialysis between January 1, 2003 and December 31, 2008, after KAF. We used Cox regression analysis for statistical associations, with mortality as the primary outcome. We identified 5,077 RTD patients and followed them for a mean of 30.9 ± 22.6 months. Adjusting for all possible confounders at the time of RTD, the adjusted hazards ratio (AHR) for death was increased with lack of arteriovenous fistula at initiation of dialysis (AHR 1.22, 95% CI 1.02-1.46, p = 0.03), albumin <3.5 g/dL (AHR 1.33, 95% CI 1.18-1.49, p = 0.0001), and being underweight (AHR 1.30, 95% CI 1.07-1.58, p = 0.006). Hemoglobin <10 g/dL (AHR 0.96, 95% CI 0.86-1.06, p = 0.46), type of insurance, and zip code-based median household income were not associated with higher mortality. Glomerular filtration rate <10 mL/min/1.73 m2 at time of dialysis initiation (AHR 0.83, 95% CI 0.75-0.93, p = 0.001) was associated with reduction in mortality. Excess mortality risk observed in patients starting dialysis after KAF is multifactorial, including nutritional issues and vascular access. Adequate preparation of patients with failing kidney transplants prior to resuming dialysis may improve outcomes. © 2017 S. Karger AG, Basel.

Publication Bias in Meta-Analysis: Confidence Intervals for Rosenthal's Fail-Safe Number.

PubMed

Fragkos, Konstantinos C; Tsagris, Michail; Frangos, Christos C

2014-01-01

The purpose of the present paper is to assess the efficacy of confidence intervals for Rosenthal's fail-safe number. Although Rosenthal's estimator is highly used by researchers, its statistical properties are largely unexplored. First of all, we developed statistical theory which allowed us to produce confidence intervals for Rosenthal's fail-safe number. This was produced by discerning whether the number of studies analysed in a meta-analysis is fixed or random. Each case produces different variance estimators. For a given number of studies and a given distribution, we provided five variance estimators. Confidence intervals are examined with a normal approximation and a nonparametric bootstrap. The accuracy of the different confidence interval estimates was then tested by methods of simulation under different distributional assumptions. The half normal distribution variance estimator has the best probability coverage. Finally, we provide a table of lower confidence intervals for Rosenthal's estimator.

Publication Bias in Meta-Analysis: Confidence Intervals for Rosenthal's Fail-Safe Number

PubMed Central

Fragkos, Konstantinos C.; Tsagris, Michail; Frangos, Christos C.

2014-01-01

The purpose of the present paper is to assess the efficacy of confidence intervals for Rosenthal's fail-safe number. Although Rosenthal's estimator is highly used by researchers, its statistical properties are largely unexplored. First of all, we developed statistical theory which allowed us to produce confidence intervals for Rosenthal's fail-safe number. This was produced by discerning whether the number of studies analysed in a meta-analysis is fixed or random. Each case produces different variance estimators. For a given number of studies and a given distribution, we provided five variance estimators. Confidence intervals are examined with a normal approximation and a nonparametric bootstrap. The accuracy of the different confidence interval estimates was then tested by methods of simulation under different distributional assumptions. The half normal distribution variance estimator has the best probability coverage. Finally, we provide a table of lower confidence intervals for Rosenthal's estimator. PMID:27437470

Role of Adjuvant Chemotherapy in ypT0-2N0 Patients Treated with Preoperative Chemoradiation Therapy and Radical Resection for Rectal Cancer

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

Park, In Ja; Kim, Dae Yong; Kim, Hee Cheol

2015-07-01

Objective: To explore the role of adjuvant chemotherapy for patients with ypT0-2N0 rectal cancer treated by preoperative chemoradiation therapy (PCRT) and radical resection. Patients and Methods: A national consortium of 10 institutions was formed, and patients with ypT0-2N0 mid- and low-rectal cancer after PCRT and radical resection from 2004 to 2009 were included. Patients were categorized into 2 groups according to receipt of additional adjuvant chemotherapy: Adj CTx (+) versus Adj CTx (−). Propensity scores were calculated and used to perform matched and adjusted analyses comparing relapse-free survival (RFS) between treatment groups while controlling for potential confounding. Results: A totalmore » of 1016 patients, who met the selection criteria, were evaluated. Of these, 106 (10.4%) did not receive adjuvant chemotherapy. There was no overall improvement in 5-year RFS as a result of adjuvant chemotherapy [91.6% for Adj CTx (+) vs 87.5% for Adj CTx (−), P=.18]. There were no differences in 5-year local recurrence and distant metastasis rate between the 2 groups. In patients who show moderate, minimal, or no regression in tumor regression grade, however, possible association of adjuvant chemotherapy with RFS would be considered (hazard ratio 0.35; 95% confidence interval 0.14-0.88; P=.03). Cox regression analysis after propensity score matching failed to show that addition of adjuvant chemotherapy was associated with improved RFS (hazard ratio 0.81; 95% confidence interval 0.39-1.70; P=.58). Conclusions: Adjuvant chemotherapy seemed to not influence the RFS of patients with ypT0-2N0 rectal cancer after PCRT followed by radical resection. Thus, the addition of adjuvant chemotherapy needs to be weighed against its oncologic benefits.« less

Performance on the adult rheumatology in-training examination and relationship to outcomes on the rheumatology certification examination.

PubMed

Lohr, Kristine M; Clauser, Amanda; Hess, Brian J; Gelber, Allan C; Valeriano-Marcet, Joanne; Lipner, Rebecca S; Haist, Steven A; Hawley, Janine L; Zirkle, Sarah; Bolster, Marcy B

2015-11-01

The American College of Rheumatology (ACR) Adult Rheumatology In-Training Examination (ITE) is a feedback tool designed to identify strengths and weaknesses in the content knowledge of individual fellows-in-training and the training program curricula. We determined whether scores on the ACR ITE, as well as scores on other major standardized medical examinations and competency-based ratings, could be used to predict performance on the American Board of Internal Medicine (ABIM) Rheumatology Certification Examination. Between 2008 and 2012, 629 second-year fellows took the ACR ITE. Bivariate correlation analyses of assessment scores and multiple linear regression analyses were used to determine whether ABIM Rheumatology Certification Examination scores could be predicted on the basis of ACR ITE scores, United States Medical Licensing Examination scores, ABIM Internal Medicine Certification Examination scores, fellowship directors' ratings of overall clinical competency, and demographic variables. Logistic regression was used to evaluate whether these assessments were predictive of a passing outcome on the Rheumatology Certification Examination. In the initial linear model, the strongest predictors of the Rheumatology Certification Examination score were the second-year fellows' ACR ITE scores (β = 0.438) and ABIM Internal Medicine Certification Examination scores (β = 0.273). Using a stepwise model, the strongest predictors of higher scores on the Rheumatology Certification Examination were second-year fellows' ACR ITE scores (β = 0.449) and ABIM Internal Medicine Certification Examination scores (β = 0.276). Based on the findings of logistic regression analysis, ACR ITE performance was predictive of a pass/fail outcome on the Rheumatology Certification Examination (odds ratio 1.016 [95% confidence interval 1.011-1.021]). The predictive value of the ACR ITE score with regard to predicting performance on the Rheumatology Certification Examination supports use of the Adult Rheumatology ITE as a valid feedback tool during fellowship training. © 2015, American College of Rheumatology.

Multivariate Regression Analysis and Slaughter Livestock,

DTIC Science & Technology

AGRICULTURE, *ECONOMICS), (*MEAT, PRODUCTION), MULTIVARIATE ANALYSIS, REGRESSION ANALYSIS , ANIMALS, WEIGHT, COSTS, PREDICTIONS, STABILITY, MATHEMATICAL MODELS, STORAGE, BEEF, PORK, FOOD, STATISTICAL DATA, ACCURACY

Regression Analysis: Legal Applications in Institutional Research

ERIC Educational Resources Information Center

Frizell, Julie A.; Shippen, Benjamin S., Jr.; Luna, Andrew L.

2008-01-01

This article reviews multiple regression analysis, describes how its results should be interpreted, and instructs institutional researchers on how to conduct such analyses using an example focused on faculty pay equity between men and women. The use of multiple regression analysis will be presented as a method with which to compare salaries of…

RAWS II: A MULTIPLE REGRESSION ANALYSIS PROGRAM,

DTIC Science & Technology

This memorandum gives instructions for the use and operation of a revised version of RAWS, a multiple regression analysis program. The program...of preprocessed data, the directed retention of variable, listing of the matrix of the normal equations and its inverse, and the bypassing of the regression analysis to provide the input variable statistics only. (Author)

Development of a reliable simulation-based test for diagnostic abdominal ultrasound with a pass/fail standard usable for mastery learning.

PubMed

Østergaard, Mia L; Nielsen, Kristina R; Albrecht-Beste, Elisabeth; Konge, Lars; Nielsen, Michael B

2018-01-01

This study aimed to develop a test with validity evidence for abdominal diagnostic ultrasound with a pass/fail-standard to facilitate mastery learning. The simulator had 150 real-life patient abdominal scans of which 15 cases with 44 findings were selected, representing level 1 from The European Federation of Societies for Ultrasound in Medicine and Biology. Four groups of experience levels were constructed: Novices (medical students), trainees (first-year radiology residents), intermediates (third- to fourth-year radiology residents) and advanced (physicians with ultrasound fellowship). Participants were tested in a standardized setup and scored by two blinded reviewers prior to an item analysis. The item analysis excluded 14 diagnoses. Both internal consistency (Cronbach's alpha 0.96) and inter-rater reliability (0.99) were good and there were statistically significant differences (p < 0.001) between all four groups, except the intermediate and advanced groups (p = 1.0). There was a statistically significant correlation between experience and test scores (Pearson's r = 0.82, p < 0.001). The pass/fail-standard failed all novices (no false positives) and passed all advanced (no false negatives). All intermediate participants and six out of 14 trainees passed. We developed a test for diagnostic abdominal ultrasound with solid validity evidence and a pass/fail-standard without any false-positive or false-negative scores. • Ultrasound training can benefit from competency-based education based on reliable tests. • This simulation-based test can differentiate between competency levels of ultrasound examiners. • This test is suitable for competency-based education, e.g. mastery learning. • We provide a pass/fail standard without false-negative or false-positive scores.

Balance failure in single limb stance due to ankle sprain injury: an analysis of center of pressure using the fractal dimension method.

PubMed

Doherty, Cailbhe; Bleakley, Chris; Hertel, Jay; Caulfield, Brian; Ryan, John; Delahunt, Eamonn

2014-01-01

Instrumented postural control analysis plays an important role in evaluating the effects of injury on dynamic stability during balance tasks, and is often conveyed with measures based on the displacement of the center-of-pressure (COP) assessed with a force platform. However, the desired outcome of the task is frequently characterized by a loss of dynamic stability, secondary to injury. Typically, these failed trials are discarded during research investigations, with the potential loss of informative data pertaining to task success. The novelty of the present study is that COP characteristics of failed trials in injured participants are compared to successful trial data in another injured group, and a control group of participants, using the fractal dimension (FD) method. Three groups of participants attempted a task of eyes closed single limb stance (SLS): twenty-nine participants with acute ankle sprain successfully completed the task on their non-injured limb (successful injury group); twenty eight participants with acute ankle sprain failed their attempt on their injured limb (failed injury group); sixteen participants with no current injury successfully completed the task on their non-dominant limb (successful non-injured group). Between trial analyses of these groups revealed significant differences in COP trajectory FD (successful injury group: 1.58±0.06; failed injury group: 1.54±0.07; successful non-injured group: 1.64±0.06) with a large effect size (0.27). These findings demonstrate that successful eyes-closed SLS is characterized by a larger FD of the COP path when compared to failed trials, and that injury causes a decrease in COP path FD. Copyright © 2014 Elsevier B.V. All rights reserved.

A Retrospective Analysis of Dental Implants Replacing Failed Implants in Grafted Maxillary Sinus: A Case Series.

PubMed

Manor, Yifat; Chaushu, Gavriel; Lorean, Adi; Mijiritzky, Eithan

2015-01-01

To evaluate the survival rate of dental implants replacing failed implants in grafted maxillary sinuses using the lateral approach vs nongrafted posterior maxillae. A retrospective analysis was conducted to study the survival of secondary dental implants inserted in the posterior maxilla in previously failed implant sites between the years 2000 and 2010. The study group consisted of patients who had also undergone maxillary sinus augmentation, and the control group consisted of patients in whom implants in the posterior maxilla had failed. Clinical and demographic data were analyzed using a structured form. Seventy-five patients with a total of 75 replaced implants were included in the study. The study group comprised 40 patients and the control group, 35 patients. None of the replaced implants in the study group failed, resulting in an overall survival of 100%; three replaced implants in the control group failed (92% survival). The main reason for the primary implant removal was lack of osseointegration (35 [87.5%] of 40 study group implants and 23 [65.7%] of 35 control group implants [P = .027]). The difference between the groups with regard to the timing of primary implant failure was statistically significant. The study group had more early failures of the primary implant than did the control group (77% vs 62%; P = .038). Dental implants replaced in the posterior maxilla had a high survival rate. A higher rate of survival was found in augmented maxillary sinus sites. Within the limits of the present study, it can be concluded that previous implant failures in the grafted maxillary sinus should not discourage practitioners from a second attempt.

Targeting regional pediatric congenital hearing loss using a spatial scan statistic.

PubMed

Bush, Matthew L; Christian, Warren Jay; Bianchi, Kristin; Lester, Cathy; Schoenberg, Nancy

2015-01-01

Congenital hearing loss is a common problem, and timely identification and intervention are paramount for language development. Patients from rural regions may have many barriers to timely diagnosis and intervention. The purpose of this study was to examine the spatial and hospital-based distribution of failed infant hearing screening testing and pediatric congenital hearing loss throughout Kentucky. Data on live births and audiological reporting of infant hearing loss results in Kentucky from 2009 to 2011 were analyzed. The authors used spatial scan statistics to identify high-rate clusters of failed newborn screening tests and permanent congenital hearing loss (PCHL), based on the total number of live births per county. The authors conducted further analyses on PCHL and failed newborn hearing screening tests, based on birth hospital data and method of screening. The authors observed four statistically significant (p < 0.05) high-rate clusters with failed newborn hearing screenings in Kentucky, including two in the Appalachian region. Hospitals using two-stage otoacoustic emission testing demonstrated higher rates of failed screening (p = 0.009) than those using two-stage automated auditory brainstem response testing. A significant cluster of high rate of PCHL was observed in Western Kentucky. Five of the 54 birthing hospitals were found to have higher relative risk of PCHL, and two of those hospitals are located in a very rural region of Western Kentucky within the cluster. This spatial analysis in children in Kentucky has identified specific regions throughout the state with high rates of congenital hearing loss and failed newborn hearing screening tests. Further investigation regarding causative factors is warranted. This method of analysis can be useful in the setting of hearing health disparities to focus efforts on regions facing high incidence of congenital hearing loss.

Influence of diabetes mellitus on postoperative complications and failure in head and neck free flap reconstruction: a systematic review and meta-analysis.

PubMed

Rosado, Pablo; Cheng, Hsu-Tang; Wu, Chao-Min; Wei, Fu-Chan

2015-04-01

We performed a systematic review and meta-analysis to determine whether diabetic patients have an increased rate of postoperative complications compared to nondiabetic patients after head and neck free flap reconstruction. A systematic review of PubMed Database between 1966 and 2012 was performed. RevMan 5.0 was used for meta-analysis. A retrospective medical chart review of 7890 patients to identify those who had a failed microsurgical reconstruction of the head and neck region at Chang Gung Memorial Hospital was also carried out. The result revealed that patients with diabetes mellitus have a 1.76 increased risk of complications (odds ratio [OR] = 1.76; 95% confidence interval [CI] = 1.11-2.79) with minimal heterogeneity (I( 2)  = 22%; p = .28). The prevalence of diabetes mellitus in patients with failed free flaps for head and neck reconstruction is 15%. The incidence of diabetes mellitus in these patients with failed free flaps is 2.3 times higher than in the general population. © 2014 Wiley Periodicals, Inc.

[Comparison of application of Cochran-Armitage trend test and linear regression analysis for rate trend analysis in epidemiology study].

PubMed

Wang, D Z; Wang, C; Shen, C F; Zhang, Y; Zhang, H; Song, G D; Xue, X D; Xu, Z L; Zhang, S; Jiang, G H

2017-05-10

We described the time trend of acute myocardial infarction (AMI) from 1999 to 2013 in Tianjin incidence rate with Cochran-Armitage trend (CAT) test and linear regression analysis, and the results were compared. Based on actual population, CAT test had much stronger statistical power than linear regression analysis for both overall incidence trend and age specific incidence trend (Cochran-Armitage trend P value

Why Students Fail at Volumetric Analysis.

ERIC Educational Resources Information Center

Pickering, Miles

1979-01-01

Investigates the reasons for students' failure in an introductory volumetric analysis course by analyzing test papers and judging them against a hypothetical ideal method of grading laboratory techniques. (GA)

Optical coherence tomography findings of bilateral foveal leukemic infiltration

PubMed Central

Le, John Q; Braich, Puneet S; Brar, Vikram S

2016-01-01

We report a case of a 59-year-old man with a history of atypical chronic myelogenous leukemia who presented with a several-week history of decreased vision in both eyes. His clinical examination revealed bilateral foveal infiltration, which was also demonstrated on optical coherence tomography. After a failed induction with imatinib (Gleevec®), he was treated with omacetaxine (Synribo®) with an appropriate hematologic response. As his leukemia improved with chemotherapy, his retinal lesions regressed as demonstrated by serial optical coherence tomography and fundus photographs, with near complete restoration of foveal architecture. PMID:27540313

A primer for biomedical scientists on how to execute model II linear regression analysis.

PubMed

Ludbrook, John

2012-04-01

1. There are two very different ways of executing linear regression analysis. One is Model I, when the x-values are fixed by the experimenter. The other is Model II, in which the x-values are free to vary and are subject to error. 2. I have received numerous complaints from biomedical scientists that they have great difficulty in executing Model II linear regression analysis. This may explain the results of a Google Scholar search, which showed that the authors of articles in journals of physiology, pharmacology and biochemistry rarely use Model II regression analysis. 3. I repeat my previous arguments in favour of using least products linear regression analysis for Model II regressions. I review three methods for executing ordinary least products (OLP) and weighted least products (WLP) regression analysis: (i) scientific calculator and/or computer spreadsheet; (ii) specific purpose computer programs; and (iii) general purpose computer programs. 4. Using a scientific calculator and/or computer spreadsheet, it is easy to obtain correct values for OLP slope and intercept, but the corresponding 95% confidence intervals (CI) are inaccurate. 5. Using specific purpose computer programs, the freeware computer program smatr gives the correct OLP regression coefficients and obtains 95% CI by bootstrapping. In addition, smatr can be used to compare the slopes of OLP lines. 6. When using general purpose computer programs, I recommend the commercial programs systat and Statistica for those who regularly undertake linear regression analysis and I give step-by-step instructions in the Supplementary Information as to how to use loss functions. © 2011 The Author. Clinical and Experimental Pharmacology and Physiology. © 2011 Blackwell Publishing Asia Pty Ltd.

Decline in bloater fecundity in Southern Lake Michigan after decline of Diporeia

USGS Publications Warehouse

Bunnell, D.B.; David, S.R.; Madenjian, C.P.

2009-01-01

Population fecundity can vary through time, sometimes owing to changes in adult condition. Consideration of these fecundity changes can improve understanding of recruitment variation. Herein, we estimated fecundity of Lake Michigan bloater Coregonus hoyi during December 2005 and February 2006. Bloater recruitment has been highly variable from 1962 to present, and consistently poor since 1992. We compared our fecundity vs. weight regression to a previously published regression that used fish sampled in October 1969. We wanted to develop a new regression for two reasons. First, it should be more accurate because it uses fish collected closer to spawning, thus minimizing the potential for atresia (egg reabsorption) which could bias fecundity high. Second, we hypothesized that fecundity would be lower in 2006 because adult condition was 41% lower in 2006 compared to 1969, likely owing to the decline of Diporeia spp, a primary prey for bloater. Although the slope of the fecundity versus weight regression was similar between the years, fecundity was 24% lower in 2006 than in 1969 for bloater weighing between 70 and 240??g. Whether this was the result of the difference in sampling time prior to spawning or of differences in condition is unknown. We also found no relationship between maternal size and mature oocyte size. Incorporating our updated fecundity regression into a stock/recruit model failed to improve the model fit, indicating that the low bloater recruitment that has been observed since the early 1990s is not solely the result of reduced fecundity. ?? 2008 Elsevier Inc. All rights reserved.

Water quality parameter measurement using spectral signatures

NASA Technical Reports Server (NTRS)

White, P. E.

1973-01-01

Regression analysis is applied to the problem of measuring water quality parameters from remote sensing spectral signature data. The equations necessary to perform regression analysis are presented and methods of testing the strength and reliability of a regression are described. An efficient algorithm for selecting an optimal subset of the independent variables available for a regression is also presented.

Multiplication factor versus regression analysis in stature estimation from hand and foot dimensions.

PubMed

Krishan, Kewal; Kanchan, Tanuj; Sharma, Abhilasha

2012-05-01

Estimation of stature is an important parameter in identification of human remains in forensic examinations. The present study is aimed to compare the reliability and accuracy of stature estimation and to demonstrate the variability in estimated stature and actual stature using multiplication factor and regression analysis methods. The study is based on a sample of 246 subjects (123 males and 123 females) from North India aged between 17 and 20 years. Four anthropometric measurements; hand length, hand breadth, foot length and foot breadth taken on the left side in each subject were included in the study. Stature was measured using standard anthropometric techniques. Multiplication factors were calculated and linear regression models were derived for estimation of stature from hand and foot dimensions. Derived multiplication factors and regression formula were applied to the hand and foot measurements in the study sample. The estimated stature from the multiplication factors and regression analysis was compared with the actual stature to find the error in estimated stature. The results indicate that the range of error in estimation of stature from regression analysis method is less than that of multiplication factor method thus, confirming that the regression analysis method is better than multiplication factor analysis in stature estimation. Copyright © 2012 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

Dysregulation of follicle development in a mouse model of premature ovarian insufficiency

PubMed Central

Grasa, P; Sheikh, S; Krzys, N; Millar, K; Janjua, S; Nawaggi, P

2016-01-01

Premature ovarian insufficiency (POI) occurs in 1% of reproductive-age women. The ovarian manifestation ranges from the presence of a variable population of follicles (follicular) to the absence of follicles (afollicular), and in the majority of cases the cause is unknown. A transgenic mouse model of follicular POI, the Double Mutant (DM), arises from oocyte-specific deletion of Mgat1 and C1galt1 required for the generation of O- and N-glycans. DM females are subfertile at 6 weeks, infertile by 9 weeks and exhibit POI by 12 weeks of age. In this study we investigate the cause of the reduced fertility at 6 weeks and infertility at 9 weeks of DM females. Ovary sections were used to analyse follicle and corpora lutea (CL) numbers, apoptosis, and levels of laminin and 3β-hydroxysteroid dehydrogenase using immunohistochemistry. After POI, DM females unexpectedly remained sexually receptive. At both 6 and 9 weeks, DM ovaries contained more primary follicles, however, at 9 weeks DM follicles were proportionally healthier, revealed by TUNEL analysis compared with Controls. In 9 week DM ovaries (collected post-mating), secondary follicles had theca and basal lamina structure abnormalities, whilst preovulatory follicles failed to ovulate resulting in the presence of numerous luteinised unruptured follicles, indicative of ovulation failure. Finally, DM ovaries contained more regressing CL with decreased luteal cell apoptosis indicative of a defect in CL regression. Identifying these follicular modifications have provided insight into the aetiology of a model of POI and highlight targets to investigate with the hope of developing new fertility treatments. PMID:27581083

A known-groups evaluation of the response bias scale in a neuropsychological setting.

PubMed

Sullivan, Karen A; Elliott, Cameron D; Lange, Rael T; Anderson, Deborah S

2013-01-01

We evaluated the Minnesota Multiphasic Personality Inventory-Second Edition (MMPI-2) Response Bias Scale (RBS). Archival data from 83 individuals who were referred for neuropsychological assessment with no formal diagnosis (n = 10), following a known or suspected traumatic brain injury (n = 36), with a psychiatric diagnosis (n = 20), or with a history of both trauma and a psychiatric condition (n = 17) were retrieved. The criteria for malingered neurocognitive dysfunction (MNCD) were applied, and two groups of participants were formed: poor effort (n = 15) and genuine responders (n = 68). Consistent with previous studies, the difference in scores between groups was greatest for the RBS (d = 2.44), followed by two established MMPI-2 validity scales, F (d = 0.25) and K (d = 0.23), and strong significant correlations were found between RBS and F (rs = .48) and RBS and K (r = -.41). When MNCD group membership was predicted using logistic regression, the RBS failed to add incrementally to F. In a separate regression to predict group membership, K added significantly to the RBS. Receiver-operating curve analysis revealed a nonsignificant area under the curve statistic, and at the ideal cutoff in this sample of >12, specificity was moderate (.79), sensitivity was low (.47), and positive and negative predictive power values at a 13% base rate were .25 and .91, respectively. Although the results of this study require replication because of a number of limitations, this study has made an important first attempt to report RBS classification accuracy statistics for predicting poor effort at a range of base rates.

Systolic blood pressure variability in patients with early severe sepsis or septic shock: a prospective cohort study.

PubMed

Tang, Yi; Sorenson, Jeff; Lanspa, Michael; Grissom, Colin K; Mathews, V J; Brown, Samuel M

2017-06-17

Severe sepsis and septic shock are often lethal syndromes, in which the autonomic nervous system may fail to maintain adequate blood pressure. Heart rate variability has been associated with outcomes in sepsis. Whether systolic blood pressure (SBP) variability is associated with clinical outcomes in septic patients is unknown. The propose of this study is to determine whether variability in SBP correlates with vasopressor independence and mortality among septic patients. We prospectively studied patients with severe sepsis or septic shock, admitted to an intensive care unit (ICU) with an arterial catheter. We analyzed SBP variability on the first 5-min window immediately following ICU admission. We performed principal component analysis of multidimensional complexity, and used the first principal component (PC 1 ) as input for Firth logistic regression, controlling for mean systolic pressure (SBP) in the primary analyses, and Acute Physiology and Chronic Health Evaluation (APACHE) II score or NEE dose in the ancillary analyses. Prespecified outcomes were vasopressor independence at 24 h (primary), and 28-day mortality (secondary). We studied 51 patients, 51% of whom achieved vasopressor independence at 24 h. Ten percent died at 28 days. PC 1 represented 26% of the variance in complexity measures. PC 1 was not associated with vasopressor independence on Firth logistic regression (OR 1.04; 95% CI: 0.93-1.16; p = 0.54), but was associated with 28-day mortality (OR 1.16, 95% CI: 1.01-1.35, p = 0.040). Early SBP variability appears to be associated with 28-day mortality in patients with severe sepsis and septic shock.

Skinfold Prediction Equations Fail to Provide an Accurate Estimate of Body Composition in Elite Rugby Union Athletes of Caucasian and Polynesian Ethnicity.

PubMed

Zemski, Adam J; Broad, Elizabeth M; Slater, Gary J

2018-01-01

Body composition in elite rugby union athletes is routinely assessed using surface anthropometry, which can be utilized to provide estimates of absolute body composition using regression equations. This study aims to assess the ability of available skinfold equations to estimate body composition in elite rugby union athletes who have unique physique traits and divergent ethnicity. The development of sport-specific and ethnicity-sensitive equations was also pursued. Forty-three male international Australian rugby union athletes of Caucasian and Polynesian descent underwent surface anthropometry and dual-energy X-ray absorptiometry (DXA) assessment. Body fat percent (BF%) was estimated using five previously developed equations and compared to DXA measures. Novel sport and ethnicity-sensitive prediction equations were developed using forward selection multiple regression analysis. Existing skinfold equations provided unsatisfactory estimates of BF% in elite rugby union athletes, with all equations demonstrating a 95% prediction interval in excess of 5%. The equations tended to underestimate BF% at low levels of adiposity, whilst overestimating BF% at higher levels of adiposity, regardless of ethnicity. The novel equations created explained a similar amount of variance to those previously developed (Caucasians 75%, Polynesians 90%). The use of skinfold equations, including the created equations, cannot be supported to estimate absolute body composition. Until a population-specific equation is established that can be validated to precisely estimate body composition, it is advocated to use a proven method, such as DXA, when absolute measures of lean and fat mass are desired, and raw anthropometry data routinely to derive an estimate of body composition change.

[Association between stress and depression levels and treatment adherence among HIV-positive individuals in Hermosillo, México].

PubMed

Piña López, Julio Alfonso; Dávila Tapia, Mariana; Sánchez-Sosa, Juan José; Togawa, Carlos; Cázares Robles, Oscar

2008-06-01

To evaluate the association between variables related to stress, reasons, and depression, and adherence to treatment in HIV-positive individuals, and to analyze the robustness according to a theoretical psychology model. This was a cross-sectional study of 25 female and 39 male HIV-positive participants receiving services at the Outpatient Center for Prevention and Treatment of HIV/AIDS and Sexually-transmitted Diseases (Centro Ambulatorio para la Prevención y Atención del VIH/Sida e Infecciones de Transmisión Sexual) in Hermosillo, Sonora, Mexico. The psychological variables, the degree of treatment adherence, stress-related circumstances, and the severity of depression were examined. Rates were calculated for the key variables associated with stress, reasons, and depression. The associations among variables were determined by multiple regression. During the month preceding the study, 65.6% of the 64 participants reported having faithfully followed the prescribed treatment, while 34.4% had failed, in some way, to follow the treatment (chi(2) = 6.250; P = 0.012). Regression analysis found that there was only one combination, an intermediate level of stress linked to tolerance of uncertainty and low levels of depression, that was significantly associated (F [3.58] = 3.298; P = 0.027) with adherence to treatment; the combination of these two variables explained 38.2% of the total variance found. The combination of stress levels with tolerance of uncertainty and depression could be used as a predictor for true compliance with prescribed treatment plans. These results should be taken into account when designing intervention and treatment-adherence campaigns in HIV-positive individuals.

Arthrodesis following failed total knee arthroplasty: comprehensive review and meta-analysis of recent literature.

PubMed

Damron, T A; McBeath, A A

1995-04-01

With the increasing duration of follow up on total knee arthroplasties, more revision arthroplasties are being performed. When revision is not advisable, a salvage procedure such as arthrodesis or resection arthroplasty is indicated. This article provides a comprehensive review of the literature regarding arthrodesis following failed total knee arthroplasty. In addition, a statistical meta-analysis of five studies using modern arthrodesis techniques is presented. A statistically significant greater fusion rate with intramedullary nail arthrodesis compared to external fixation is documented. Gram negative and mixed infections are found to be significant risk factors for failure of arthrodesis.

Failure Investigation of a Cage Suspension Gear Chain used in Coal Mines

NASA Astrophysics Data System (ADS)

Ghosh, Debashis; Dutta, Shamik; Shukla, Awdhesh Kumar; Roy, Himadri

2016-10-01

This investigation is primarily aimed to examine the probable causes of in-service failure of cage suspension gear chain used in coal mines. Preliminary visual examination, dimensional measurement, chemical analysis, magnetic particle inspection and estimation of mechanical properties are necessary supplement to this investigation. Optical microscopic analysis along with scanning electron microscopy examinations are carried out to understand the metallurgical reasons for failure. The visual examination and magnetic particle investigations reveal presence of fissure cracks at weld joint for both un-failed and failed end link chain. The average hardness value has been found to increase gradually with the distance from the weld interface. The macro and microstructural examinations of the samples prepared from both failed and un-failed specimens depict presence of continuous as well as aligned linear inclusions randomly distributed along with decarburized layer at weld interface/fusion zone. Fractographic examination shows flat fracture covering major portion of cross-section, which is surrounded by a narrow annular metallic fracture surface having a texture different from that of the remaining surface. Fracture mechanics principles have been used to study the fatigue crack growth rate in both weld region and base region of the un-failed gear chain material. Detailed stress analyses are also carried out to evaluate the stress generated along the chain periphery. Finally, it is concluded that presence of serious weld defect due to use of improper welding parameters/procedure caused failure of the end links of the investigated chain link.

Using Robust Standard Errors to Combine Multiple Regression Estimates with Meta-Analysis

ERIC Educational Resources Information Center

Williams, Ryan T.

2012-01-01

Combining multiple regression estimates with meta-analysis has continued to be a difficult task. A variety of methods have been proposed and used to combine multiple regression slope estimates with meta-analysis, however, most of these methods have serious methodological and practical limitations. The purpose of this study was to explore the use…

A Quality Assessment Tool for Non-Specialist Users of Regression Analysis

ERIC Educational Resources Information Center

Argyrous, George

2015-01-01

This paper illustrates the use of a quality assessment tool for regression analysis. It is designed for non-specialist "consumers" of evidence, such as policy makers. The tool provides a series of questions such consumers of evidence can ask to interrogate regression analysis, and is illustrated with reference to a recent study published…

A retrospective analysis to identify the factors affecting infection in patients undergoing chemotherapy.

PubMed

Park, Ji Hyun; Kim, Hyeon-Young; Lee, Hanna; Yun, Eun Kyoung

2015-12-01

This study compares the performance of the logistic regression and decision tree analysis methods for assessing the risk factors for infection in cancer patients undergoing chemotherapy. The subjects were 732 cancer patients who were receiving chemotherapy at K university hospital in Seoul, Korea. The data were collected between March 2011 and February 2013 and were processed for descriptive analysis, logistic regression and decision tree analysis using the IBM SPSS Statistics 19 and Modeler 15.1 programs. The most common risk factors for infection in cancer patients receiving chemotherapy were identified as alkylating agents, vinca alkaloid and underlying diabetes mellitus. The logistic regression explained 66.7% of the variation in the data in terms of sensitivity and 88.9% in terms of specificity. The decision tree analysis accounted for 55.0% of the variation in the data in terms of sensitivity and 89.0% in terms of specificity. As for the overall classification accuracy, the logistic regression explained 88.0% and the decision tree analysis explained 87.2%. The logistic regression analysis showed a higher degree of sensitivity and classification accuracy. Therefore, logistic regression analysis is concluded to be the more effective and useful method for establishing an infection prediction model for patients undergoing chemotherapy. Copyright © 2015 Elsevier Ltd. All rights reserved.

Visual grading characteristics and ordinal regression analysis during optimisation of CT head examinations.

PubMed

Zarb, Francis; McEntee, Mark F; Rainford, Louise

2015-06-01

To evaluate visual grading characteristics (VGC) and ordinal regression analysis during head CT optimisation as a potential alternative to visual grading assessment (VGA), traditionally employed to score anatomical visualisation. Patient images (n = 66) were obtained using current and optimised imaging protocols from two CT suites: a 16-slice scanner at the national Maltese centre for trauma and a 64-slice scanner in a private centre. Local resident radiologists (n = 6) performed VGA followed by VGC and ordinal regression analysis. VGC alone indicated that optimised protocols had similar image quality as current protocols. Ordinal logistic regression analysis provided an in-depth evaluation, criterion by criterion allowing the selective implementation of the protocols. The local radiology review panel supported the implementation of optimised protocols for brain CT examinations (including trauma) in one centre, achieving radiation dose reductions ranging from 24 % to 36 %. In the second centre a 29 % reduction in radiation dose was achieved for follow-up cases. The combined use of VGC and ordinal logistic regression analysis led to clinical decisions being taken on the implementation of the optimised protocols. This improved method of image quality analysis provided the evidence to support imaging protocol optimisation, resulting in significant radiation dose savings. • There is need for scientifically based image quality evaluation during CT optimisation. • VGC and ordinal regression analysis in combination led to better informed clinical decisions. • VGC and ordinal regression analysis led to dose reductions without compromising diagnostic efficacy.

REGRESSION ANALYSIS OF SEA-SURFACE-TEMPERATURE PATTERNS FOR THE NORTH PACIFIC OCEAN.

DTIC Science & Technology

SEA WATER, *SURFACE TEMPERATURE, *OCEANOGRAPHIC DATA, PACIFIC OCEAN, REGRESSION ANALYSIS , STATISTICAL ANALYSIS, UNDERWATER EQUIPMENT, DETECTION, UNDERWATER COMMUNICATIONS, DISTRIBUTION, THERMAL PROPERTIES, COMPUTERS.

76 FR 6536 - Airworthiness Directives; Bombardier, Inc. Model CL-215-1A10 (CL-215), CL-215-6B11 (CL-215T...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-07

... analysis of the systems and structure in the potential line of trajectory of a failed screw cap/end cap for... of aileron control [and consequent reduced controllability of the airplane]. * * * * * We are issuing... in the potential line of trajectory of a failed screw cap/end cap for each accumulator has been...

The Midwest flood of 1993: did trees protect levees along the Missouri River?

Treesearch

John P. Dwyer; Douglas Wallace; David R. Larsen

1997-01-01

Following the Midwest flood of 1993, a study was initiated along a 39-mile segment of the Missouri River to determine if there was an association between woody corridors and levee stability. A systematic sample of levee failures revealed that primary levees which did not fail had a significantly wider woody corridor than failed levees. Analysis of the total inventory...

The process and utility of classification and regression tree methodology in nursing research

PubMed Central

Kuhn, Lisa; Page, Karen; Ward, John; Worrall-Carter, Linda

2014-01-01

Aim This paper presents a discussion of classification and regression tree analysis and its utility in nursing research. Background Classification and regression tree analysis is an exploratory research method used to illustrate associations between variables not suited to traditional regression analysis. Complex interactions are demonstrated between covariates and variables of interest in inverted tree diagrams. Design Discussion paper. Data sources English language literature was sourced from eBooks, Medline Complete and CINAHL Plus databases, Google and Google Scholar, hard copy research texts and retrieved reference lists for terms including classification and regression tree* and derivatives and recursive partitioning from 1984–2013. Discussion Classification and regression tree analysis is an important method used to identify previously unknown patterns amongst data. Whilst there are several reasons to embrace this method as a means of exploratory quantitative research, issues regarding quality of data as well as the usefulness and validity of the findings should be considered. Implications for Nursing Research Classification and regression tree analysis is a valuable tool to guide nurses to reduce gaps in the application of evidence to practice. With the ever-expanding availability of data, it is important that nurses understand the utility and limitations of the research method. Conclusion Classification and regression tree analysis is an easily interpreted method for modelling interactions between health-related variables that would otherwise remain obscured. Knowledge is presented graphically, providing insightful understanding of complex and hierarchical relationships in an accessible and useful way to nursing and other health professions. PMID:24237048

The process and utility of classification and regression tree methodology in nursing research.

PubMed

Kuhn, Lisa; Page, Karen; Ward, John; Worrall-Carter, Linda

2014-06-01

This paper presents a discussion of classification and regression tree analysis and its utility in nursing research. Classification and regression tree analysis is an exploratory research method used to illustrate associations between variables not suited to traditional regression analysis. Complex interactions are demonstrated between covariates and variables of interest in inverted tree diagrams. Discussion paper. English language literature was sourced from eBooks, Medline Complete and CINAHL Plus databases, Google and Google Scholar, hard copy research texts and retrieved reference lists for terms including classification and regression tree* and derivatives and recursive partitioning from 1984-2013. Classification and regression tree analysis is an important method used to identify previously unknown patterns amongst data. Whilst there are several reasons to embrace this method as a means of exploratory quantitative research, issues regarding quality of data as well as the usefulness and validity of the findings should be considered. Classification and regression tree analysis is a valuable tool to guide nurses to reduce gaps in the application of evidence to practice. With the ever-expanding availability of data, it is important that nurses understand the utility and limitations of the research method. Classification and regression tree analysis is an easily interpreted method for modelling interactions between health-related variables that would otherwise remain obscured. Knowledge is presented graphically, providing insightful understanding of complex and hierarchical relationships in an accessible and useful way to nursing and other health professions. © 2013 The Authors. Journal of Advanced Nursing Published by John Wiley & Sons Ltd.

Advantages of the net benefit regression framework for economic evaluations of interventions in the workplace: a case study of the cost-effectiveness of a collaborative mental health care program for people receiving short-term disability benefits for psychiatric disorders.

PubMed

Hoch, Jeffrey S; Dewa, Carolyn S

2014-04-01

Economic evaluations commonly accompany trials of new treatments or interventions; however, regression methods and their corresponding advantages for the analysis of cost-effectiveness data are not well known. To illustrate regression-based economic evaluation, we present a case study investigating the cost-effectiveness of a collaborative mental health care program for people receiving short-term disability benefits for psychiatric disorders. We implement net benefit regression to illustrate its strengths and limitations. Net benefit regression offers a simple option for cost-effectiveness analyses of person-level data. By placing economic evaluation in a regression framework, regression-based techniques can facilitate the analysis and provide simple solutions to commonly encountered challenges. Economic evaluations of person-level data (eg, from a clinical trial) should use net benefit regression to facilitate analysis and enhance results.

Clinical and histopathological factors affecting failed sentinel node localization in axillary staging for breast cancer.

PubMed

Dordea, Matei; Colvin, Hugh; Cox, Phil; Pujol Nicolas, Andrea; Kanakala, Venkat; Iwuchukwu, Obi

2013-04-01

Sentinel lymph node biopsy (SLNB) has become the standard of care in axillary staging of clinically node-negative breast cancer patients. To analyze reasons for failure of SLN localization by means of a multivariate analysis of clinical and histopathological factors. We performed a review of 164 consecutive breast cancer patients who underwent SLNB. A superficial injection technique was used. 9/164 patients failed to show nodes. In 7/9 patients no evidence of radioactivity or blue dye was observed. Age and nodal status were the only statistically significant factors (p < 0.05). For every unit increase in age there was a 9% reduced chance of failed SLN localization. Patients with negative nodal status have 90% reduced risk of failed sentinel node localization than patients with macro or extra capsular nodal invasion. The results suggest that altered lymphatic dynamics secondary to tumour burden may play a role in failed sentinel node localization. We showed that in all failed localizations the radiocolloid persisted around the injection site, showing limited local diffusion only. While clinical and histopathological data may provide some clues as to why sentinel node localization fails, we further hypothesize that integrity of peri-areolar lymphatics is important for successful localization. Copyright © 2012 Royal College of Surgeons of Edinburgh (Scottish charity number SC005317) and Royal College of Surgeons in Ireland. Published by Elsevier Ltd. All rights reserved.

Factors Influencing Enrollment in the Medication Therapy Management Clinic at an Academic Ambulatory Care Clinic.

PubMed

Shah, Mansi; Tilton, Jessica; Kim, Shiyun

2016-04-01

In 2001, the University of Illinois Hospital and Health Sciences System (UI Health) established a pharmacist-run, referral-based medication therapy management clinic (MTMC). Referrals are obtained from any UI Health provider or by self-referral. Although there is a high volume of referrals, a large percentage of patients do not enroll. This study was designed to determine the various factors that influence patient enrollment in the MTMC. This study was a retrospective chart review of demographic and patient variable data during years 2010 and 2011. Disabilities, distance from MTMC, mode of transportation, past medical history, and appointment dates were extracted from the medical records. Results were analyzed using descriptive statistics and logistic regression analysis. A total of 103 referrals were made; however, only 17% of patients remain enrolled in MTMC. The baseline demographics included a mean age of 63 years, 68% female, 70% African American, and 81% English speaking. Patients lived an average of 8 miles from MTMC; most utilized public or government-supplemented transport services; 24% of patients reported some type of disability, most commonly utilizing a walker or a wheelchair. On average, patients were prescribed 13 medications with hypertension (70%), diabetes (56%), and hyperlipidemia (48%) being the most common chronic disease states. The reason for referral included medication management, education, medication reconciliation, and disease state management. Five patients were unable to be contacted to schedule an initial appointment. Additionally, 18 patients failed their scheduled initial appointment and did not reschedule. Logistic regression analysis demonstrated distance traveled for clinic visit, age, and history of hypertension affected the probability of patients showing for their appointments (chi-square = 19.7, P < .001). This study demonstrated that distance from MTMC is the most common barrier in patient enrollment; therefore, strategies to improve patient access are necessary. © The Author(s) 2014.

Uterine Fibroids: Correlation of T2 Signal Intensity with Semiquantitative Perfusion MR Parameters in Patients Screened for MR-guided High-Intensity Focused Ultrasound Ablation.

PubMed

Kim, Young-Sun; Lee, Jeong-Won; Choi, Chel Hun; Kim, Byoung-Gie; Bae, Duk-Soo; Rhim, Hyunchul; Lim, Hyo Keun

2016-03-01

To evaluate the relationships between T2 signal intensity and semiquantitative perfusion magnetic resonance (MR) parameters of uterine fibroids in patients who were screened for MR-guided high-intensity focused ultrasound (HIFU) ablation. Institutional review board approval was granted, and informed consents were waived. One hundred seventy most symptom-relevant, nondegenerated uterine fibroids (mean diameter, 7.3 cm; range, 3.0-17.2 cm) in 170 women (mean age, 43.5 years; range, 24-56 years) undergoing screening MR examinations for MR-guided HIFU ablation from October 2009 to April 2014 were retrospectively analyzed. Fibroid signal intensity was assessed as the ratio of the fibroid T2 signal intensity to that of skeletal muscle. Parameters of semiquantitative perfusion MR imaging obtained during screening MR examination (peak enhancement, percentage of relative peak enhancement, time to peak [in seconds], wash-in rate [per seconds], and washout rate [per seconds]) were investigated to assess their relationships with T2 signal ratio by using multiple linear regression analysis. Correlations between T2 signal intensity and independently significant perfusion parameters were then evaluated according to fibroid type by using Spearman correlation test. Multiple linear regression analysis revealed that relative peak enhancement showed an independently significant correlation with T2 signal ratio (Β = 0.004, P < .001). Submucosal intracavitary (n = 20, ρ = 0.275, P = .240) and type III (n = 18, ρ = 0.082, P = .748) fibroids failed to show significant correlations between perfusion and T2 signal intensity, while significant correlations were found for all other fibroid types (ρ = 0.411-0.629, P < .05). In possible candidates for MR-guided HIFU ablation, the T2 signal intensity of nondegenerated uterine fibroids showed an independently significant positive correlation with relative peak enhancement in most cases, except those of submucosal intracavitary or type III fibroids.

Pathways-Driven Sparse Regression Identifies Pathways and Genes Associated with High-Density Lipoprotein Cholesterol in Two Asian Cohorts

PubMed Central

Silver, Matt; Chen, Peng; Li, Ruoying; Cheng, Ching-Yu; Wong, Tien-Yin; Tai, E-Shyong; Teo, Yik-Ying; Montana, Giovanni

2013-01-01

Standard approaches to data analysis in genome-wide association studies (GWAS) ignore any potential functional relationships between gene variants. In contrast gene pathways analysis uses prior information on functional structure within the genome to identify pathways associated with a trait of interest. In a second step, important single nucleotide polymorphisms (SNPs) or genes may be identified within associated pathways. The pathways approach is motivated by the fact that genes do not act alone, but instead have effects that are likely to be mediated through their interaction in gene pathways. Where this is the case, pathways approaches may reveal aspects of a trait's genetic architecture that would otherwise be missed when considering SNPs in isolation. Most pathways methods begin by testing SNPs one at a time, and so fail to capitalise on the potential advantages inherent in a multi-SNP, joint modelling approach. Here, we describe a dual-level, sparse regression model for the simultaneous identification of pathways and genes associated with a quantitative trait. Our method takes account of various factors specific to the joint modelling of pathways with genome-wide data, including widespread correlation between genetic predictors, and the fact that variants may overlap multiple pathways. We use a resampling strategy that exploits finite sample variability to provide robust rankings for pathways and genes. We test our method through simulation, and use it to perform pathways-driven gene selection in a search for pathways and genes associated with variation in serum high-density lipoprotein cholesterol levels in two separate GWAS cohorts of Asian adults. By comparing results from both cohorts we identify a number of candidate pathways including those associated with cardiomyopathy, and T cell receptor and PPAR signalling. Highlighted genes include those associated with the L-type calcium channel, adenylate cyclase, integrin, laminin, MAPK signalling and immune function. PMID:24278029

Pathways-driven sparse regression identifies pathways and genes associated with high-density lipoprotein cholesterol in two Asian cohorts.

PubMed

Silver, Matt; Chen, Peng; Li, Ruoying; Cheng, Ching-Yu; Wong, Tien-Yin; Tai, E-Shyong; Teo, Yik-Ying; Montana, Giovanni

2013-11-01

Standard approaches to data analysis in genome-wide association studies (GWAS) ignore any potential functional relationships between gene variants. In contrast gene pathways analysis uses prior information on functional structure within the genome to identify pathways associated with a trait of interest. In a second step, important single nucleotide polymorphisms (SNPs) or genes may be identified within associated pathways. The pathways approach is motivated by the fact that genes do not act alone, but instead have effects that are likely to be mediated through their interaction in gene pathways. Where this is the case, pathways approaches may reveal aspects of a trait's genetic architecture that would otherwise be missed when considering SNPs in isolation. Most pathways methods begin by testing SNPs one at a time, and so fail to capitalise on the potential advantages inherent in a multi-SNP, joint modelling approach. Here, we describe a dual-level, sparse regression model for the simultaneous identification of pathways and genes associated with a quantitative trait. Our method takes account of various factors specific to the joint modelling of pathways with genome-wide data, including widespread correlation between genetic predictors, and the fact that variants may overlap multiple pathways. We use a resampling strategy that exploits finite sample variability to provide robust rankings for pathways and genes. We test our method through simulation, and use it to perform pathways-driven gene selection in a search for pathways and genes associated with variation in serum high-density lipoprotein cholesterol levels in two separate GWAS cohorts of Asian adults. By comparing results from both cohorts we identify a number of candidate pathways including those associated with cardiomyopathy, and T cell receptor and PPAR signalling. Highlighted genes include those associated with the L-type calcium channel, adenylate cyclase, integrin, laminin, MAPK signalling and immune function.

CADDIS Volume 4. Data Analysis: Basic Analyses

EPA Pesticide Factsheets

Use of statistical tests to determine if an observation is outside the normal range of expected values. Details of CART, regression analysis, use of quantile regression analysis, CART in causal analysis, simplifying or pruning resulting trees.

Population heterogeneity in the salience of multiple risk factors for adolescent delinquency.

PubMed

Lanza, Stephanie T; Cooper, Brittany R; Bray, Bethany C

2014-03-01

To present mixture regression analysis as an alternative to more standard regression analysis for predicting adolescent delinquency. We demonstrate how mixture regression analysis allows for the identification of population subgroups defined by the salience of multiple risk factors. We identified population subgroups (i.e., latent classes) of individuals based on their coefficients in a regression model predicting adolescent delinquency from eight previously established risk indices drawn from the community, school, family, peer, and individual levels. The study included N = 37,763 10th-grade adolescents who participated in the Communities That Care Youth Survey. Standard, zero-inflated, and mixture Poisson and negative binomial regression models were considered. Standard and mixture negative binomial regression models were selected as optimal. The five-class regression model was interpreted based on the class-specific regression coefficients, indicating that risk factors had varying salience across classes of adolescents. Standard regression showed that all risk factors were significantly associated with delinquency. Mixture regression provided more nuanced information, suggesting a unique set of risk factors that were salient for different subgroups of adolescents. Implications for the design of subgroup-specific interventions are discussed. Copyright © 2014 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Insulin-like Growth Factor 1 (IGF-1) Stabilizes Nascent Blood Vessels*

PubMed Central

Jacobo, Sarah Melissa P.; Kazlauskas, Andrius

2015-01-01

Here we report that VEGF-A and IGF-1 differ in their ability to stabilize newly formed blood vessels and endothelial cell tubes. Although VEGF-A failed to support an enduring vascular response, IGF-1 stabilized neovessels generated from primary endothelial cells derived from various vascular beds and mouse retinal explants. In these experimental systems, destabilization/regression was driven by lysophosphatidic acid (LPA). Because previous studies have established that Erk antagonizes LPA-mediated regression, we considered whether Erk was an essential component of IGF-dependent stabilization. Indeed, IGF-1 lost its ability to stabilize neovessels when the Erk pathway was inhibited pharmacologically. Furthermore, stabilization was associated with prolonged Erk activity. In the presence of IGF-1, Erk activity persisted longer than in the presence of VEGF or LPA alone. These studies reveal that VEGF and IGF-1 can have distinct inputs in the angiogenic process. In contrast to VEGF, IGF-1 stabilizes neovessels, which is dependent on Erk activity and associated with prolonged activation. PMID:25564613

Robust nonlinear system identification: Bayesian mixture of experts using the t-distribution

NASA Astrophysics Data System (ADS)

Baldacchino, Tara; Worden, Keith; Rowson, Jennifer

2017-02-01

A novel variational Bayesian mixture of experts model for robust regression of bifurcating and piece-wise continuous processes is introduced. The mixture of experts model is a powerful model which probabilistically splits the input space allowing different models to operate in the separate regions. However, current methods have no fail-safe against outliers. In this paper, a robust mixture of experts model is proposed which consists of Student-t mixture models at the gates and Student-t distributed experts, trained via Bayesian inference. The Student-t distribution has heavier tails than the Gaussian distribution, and so it is more robust to outliers, noise and non-normality in the data. Using both simulated data and real data obtained from the Z24 bridge this robust mixture of experts performs better than its Gaussian counterpart when outliers are present. In particular, it provides robustness to outliers in two forms: unbiased parameter regression models, and robustness to overfitting/complex models.

Preoperative ultrasound measurements predict the feasibility of gallbladder extraction during transgastric natural orifice translumenal endoscopic surgery cholecystectomy.

PubMed

Santos, Byron F; Auyang, Edward D; Hungness, Eric S; Desai, Kush R; Chan, Edward S; van Beek, Darren B; Wang, Edward C; Soper, Nathaniel J

2011-04-01

Extraction of a gallbladder through an endoscopic overtube during natural orifice translumenal endoscopic surgery (NOTES) transgastric cholecystectomy avoids potential injury to the esophagus. This study examined the rate of successful gallbladder specimen extraction through an overtube and hypothesized that preoperative ultrasound findings could predict successful specimen passage. Gallbladder specimens from patients undergoing laparoscopic cholecystectomy were measured, and an attempt was made to pull the specimens through a commercially available overtube with an inner diameter of 16.7-mm. A radiologist blinded to the outcomes reviewed the available preoperative ultrasound measurements from these patients. Ultrasound dimensions including gallbladder length, width, and depth; wall thickness; common bile duct diameter; and size of the largest gallstone (LGS) were recorded. Multiple logistic regression analysis was performed to determine whether ultrasound findings and patient characteristics (age, body mass index [BMI], and sex) could predict the ability of a specimen to pass through the overtube. Of 57 patients, 44 (77%) who had preoperative ultrasounds available for electronic review were included in the final analysis. Gallstones were present in 35 (79%) of these 44 patients. Intraoperative gallbladder perforation occurred in 18 (41%) of the 44 patients, and 16 (36%) of the 44 gallbladders could be extracted through the overtube. Measurement of LGS was possible for 23 patients, and indeterminate gallstone size (IGS) was determined for 12 patients. The rate for passage of perforated versus intact gallbladders was similar (40% vs. 23%; p = 0.054). The LGS (odds ratio [OR], 1.17; 95% confidence interval [CI], 1.02-1.33; p = 0.021) and IGS (OR, 22.97; 95% CI, 1.99-265.63; p = 0.025) predicted failed passage on multivariate logistic regression analysis. The passage rate was 80% for LGS smaller than 10 mm or no stones present, 18% for LGS 10 mm or larger, and 8% for IGS (p < 0.001). A majority of cholecystectomy specimens cannot pass through an endoscopic overtube. Preoperative ultrasound findings can predict successful specimen extraction. An IGS or a gallstone 10 mm or larger should be considered a relative contraindication to transgastric NOTES cholecystectomy.

Impact of flavor attributes on consumer liking of Swiss cheese.

PubMed

Liggett, R E; Drake, M A; Delwiche, J F

2008-02-01

Although Swiss cheese is growing in popularity, no research has examined what flavor characteristics consumers desire in Swiss cheese, which was the main objective of this study. To this end, a large group of commercially available Swiss-type cheeses (10 domestic Swiss cheeses, 4 domestic Baby Swiss cheeses, and one imported Swiss Emmenthal) were assessed both by 12 trained panelists for flavor and feeling factors and by 101 consumers for overall liking. In addition, a separate panel of 24 consumers rated the same cheeses for dissimilarity. On the basis of liking ratings, the 101 consumers were segmented by cluster analysis into 2 groups: nondistinguishers (n = 40) and varying responders (n = 61). Partial least squares regression, a statistical modeling technique that relates 2 data sets (in this case, a set of descriptive analysis data and a set of consumer liking data), was used to determine which flavor attributes assessed by the trained panel were important variables in overall liking of the cheeses for the varying responders. The model explained 93% of the liking variance on 3 normally distributed components and had 49% predictability. Diacetyl, whey, milk fat, and umami were found to be drivers of liking, whereas cabbage, cooked, and vinegar were drivers of disliking. Nutty flavor was not particularly important to liking and it was present in only 2 of the cheeses. The dissimilarity ratings were combined with the liking ratings of both segments and analyzed by probabilistic multidimensional scaling. The ideals of each segment completely overlapped, with the variance of the varying responders being smaller than the variance of the non-distinguishers. This model indicated that the Baby Swiss cheeses were closer to the consumers' ideals than were the other cheeses. Taken together, the 2 models suggest that the partial least squares regression failed to capture one or more attributes that contribute to consumer acceptance, although the descriptive analysis of flavor and feeling factors was able to account for 93% of the variance in the liking ratings. These findings indicate the flavor characteristics Swiss cheese producers should optimize, and minimize, to create cheeses that best match consumer desires.

A Note on the Relationship between the Number of Indicators and Their Reliability in Detecting Regression Coefficients in Latent Regression Analysis

ERIC Educational Resources Information Center

Dolan, Conor V.; Wicherts, Jelte M.; Molenaar, Peter C. M.

2004-01-01

We consider the question of how variation in the number and reliability of indicators affects the power to reject the hypothesis that the regression coefficients are zero in latent linear regression analysis. We show that power remains constant as long as the coefficient of determination remains unchanged. Any increase in the number of indicators…

Failure Analysis of Fractured Poppet from Space Shuttle Orbiter Flow Control Valve

NASA Technical Reports Server (NTRS)

Russell, Richard

2010-01-01

This slide presentation reviews the failure analysis of a fractured poppet from a flow control valve (FCV) used on the space shuttle. This presentation has focused on the laboratory analysis of the failed hardware. The use of Scanning electron fractography during the investigation led to the conclusion that the poppet failed due to fatigue cracking that, most likely, occurred under changing loading conditions. The initial investigation led to a more thorough test of poppets that had been retired, this testing led to the conclusion that the thumbnail cracks in the flight hardware had existed for the life of the shuttle program. This led to a program to develop an eddy current technique that was capable of detecting small very tight cracks.

Association between attempted suicide and academic performance indicators among middle and high school students in Mexico: results from a national survey.

PubMed

Orozco, Ricardo; Benjet, Corina; Borges, Guilherme; Moneta Arce, María Fátima; Fregoso Ito, Diana; Fleiz, Clara; Villatoro, Jorge Ameth

2018-01-01

Students' mental health is associated to academic performance. In high income countries, higher students' grades are related to lower odds of suicidal behaviors, but studies on other indicators of academic performance are more limited, specially in middle income countries. Data from 28,519 middle and high school students selected with multistage clustered sampling in the Mexican National Survey of Student's Drug Use. Using a self-administered questionnaire, lifetime suicidal attempt and four indicators of academic performance were assessed: age inconsistency with grade level, not being a student in the last year, perceived academic performance and number of failed courses. Multiple logistic regression models were used to control for sociodemographic and school characteristics. The lifetime prevalence of attempted suicide was 3.0% for middle school students and 4.2% for high school students. Among middle school students, statistically adjusted significant associations of suicide attempt with academic performance indicators were: not being a student the year before, worse self-perceived performance and a higher number of failed courses; among high school students, predictors were failed courses and self-perceived academic performance, with ORs of 1.65 and 1.96 for the categories of good and fair/poor respectively, compared to those who reported very good performance. Self-perceived academic performance was the main indicator for suicide in both school levels. Suicide prevention efforts in Mexico's schools should include asking students about the perception they have about their own academic performance.

Transcranial Doppler quantification of residual shunt after percutaneous patent foramen ovale closure: correlation of device efficacy with intracardiac anatomic measures.

PubMed

Sorensen, Sherman G; Spruance, Spotswood L; Smout, Randall; Horn, Susan

2012-06-01

Percutaneous, mechanical closure of defects of the atrial septum fails to completely resolve shunting in up to 20% of cases. Little is known about the factors associated with device failure. We measured the left atrial opening (X), right atrial opening (Z), tunnel length (Y), septum secundum, device-septum primum separation, and tunnel compressibility of the patent foramen ovale (PFO) in 301 patients with cryptogenic neurological events, PFO anatomy, and severe Valsalva shunting (Spencer Grade 5-5+). All patients then underwent percutaneous closure with the GORE®HELEX Septal Occluder device and were evaluated at 3 months for residual shunt by transcranial Doppler (TCD). Severe residual Valsalva shunt (TCD Grade 5-5+) was found at 3 months in 21 of 301 (7%) patients. X, Y, and Z were associated with failure with a high degree of statistical significance, whereas the width of the septum secundum, device-septum primum separation, and tunnel compressibility were not. An unanticipated finding was that 14 of 35 (40%) patients sized with a large balloon failed compared with 9 of 280 (3%) sized with a small balloon (P < 0.0001). In the multivariate logistic regression model, X (P = < 0.0001) and balloon size (P < 0.0001) were both strong predictors of failure. In an intracardiac echocardiography-defined PFO population, characterized by severe baseline Valsalva shunt and a high incidence of persistent (rest) shunting, association of six intracardiac measurements to closure device failure by multivariate logistic regression showed that the width of the left atrial opening was a strong predictor of residual shunting. An unanticipated finding was that use of a large sizing balloon was also strongly associated with failure. ©2012, Wiley Periodicals, Inc.

Prediction of successful weight reduction after bariatric surgery by data mining technologies.

PubMed

Lee, Yi-Chih; Lee, Wei-Jei; Lee, Tian-Shyug; Lin, Yang-Chu; Wang, Weu; Liew, Phui-Ly; Huang, Ming-Te; Chien, Ching-Wen

2007-09-01

Surgery is the only long-lasting effective treatment for morbid obesity. Prediction on successful weight loss after surgery by data mining technologies is lacking. We analyze the available information during the initial evaluation of patients referred to bariatric surgery by data mining methods for predictors of successful weight loss. 249 patients undergoing laparoscopic mini-gastric bypass (LMGB) or adjustable gastric banding (LAGB) were enrolled. Logistic Regression and Artificial Neural Network (ANN) technologies were used to predict weight loss. Overall classification capability of the designed diagnostic models was evaluated by the misclassification costs. We studied 249 patients consisting of 72 men and 177 women over 2 years. Mean age was 33 +/- 9 years. 208 (83.5%) patients had successful weight reduction while 41 (16.5%) did not. Logistic Regression revealed that the type of operation had a significant prediction effect (P = 0.000). Patients receiving LMGB had a better weight loss than those receiving LAGB (78.54% +/- 26.87 vs 43.65% +/- 26.08). ANN provided the same predicted factor on the type of operation but it further proposed that HbAlc and triglyceride were associated with success. HbAlc is lower in the successful than failed group (5.81 +/- 1.06 vs 6.05 +/- 1.49; P = NS), and triglyceride in the successful group is higher than in the failed group (171.29 +/- 112.62 vs 144.07 +/- 89.90; P = NS). Artificial neural network is a better modeling technique and the overall predictive accuracy is higher on the basis of multiple variables related to laboratory tests. LMGB, high preoperative triglyceride level, and low HbAlc level can predict successful weight reduction at 2 years.

Predicting failing performance on a standardized patient clinical performance examination: the importance of communication and professionalism skills deficits.

PubMed

Chang, Anna; Boscardin, Christy; Chou, Calvin L; Loeser, Helen; Hauer, Karen E

2009-10-01

The purpose is to determine which assessment measures identify medical students at risk of failing a clinical performance examination (CPX). Retrospective case-control, multiyear design, contingency table analysis, n = 149. We identified two predictors of CPX failure in patient-physician interaction skills: low clerkship ratings (odds ratio 1.79, P = .008) and student progress review for communication or professionalism concerns (odds ratio 2.64, P = .002). No assessments predicted CPX failure in clinical skills. Performance concerns in communication and professionalism identify students at risk of failing the patient-physician interaction portion of a CPX. This correlation suggests that both faculty and standardized patients can detect noncognitive traits predictive of failing performance. Early identification of these students may allow for development of a structured supplemental curriculum with increased opportunities for practice and feedback. The lack of predictors in the clinical skills portion suggests limited faculty observation or feedback.

Murine Intracisternal A Type Particles Fail to Separate from the Membrane of the Endoplasmic Reticulum

PubMed Central

Perk, Kalman; Dahlberg, John E.

1974-01-01

Analysis of serial sections of murine cells containing intracisternal A particles revealed that over 99% of all A particles remain in a budding configuration. This indicates that these particles fail to detach from the membrane of the endoplasmic reticulum. This observation explains how, despite their intracellular abundance in certain murine tumors, no extracellular A-type particles can be found. Images PMID:4431082

Moderation analysis using a two-level regression model.

PubMed

Yuan, Ke-Hai; Cheng, Ying; Maxwell, Scott

2014-10-01

Moderation analysis is widely used in social and behavioral research. The most commonly used model for moderation analysis is moderated multiple regression (MMR) in which the explanatory variables of the regression model include product terms, and the model is typically estimated by least squares (LS). This paper argues for a two-level regression model in which the regression coefficients of a criterion variable on predictors are further regressed on moderator variables. An algorithm for estimating the parameters of the two-level model by normal-distribution-based maximum likelihood (NML) is developed. Formulas for the standard errors (SEs) of the parameter estimates are provided and studied. Results indicate that, when heteroscedasticity exists, NML with the two-level model gives more efficient and more accurate parameter estimates than the LS analysis of the MMR model. When error variances are homoscedastic, NML with the two-level model leads to essentially the same results as LS with the MMR model. Most importantly, the two-level regression model permits estimating the percentage of variance of each regression coefficient that is due to moderator variables. When applied to data from General Social Surveys 1991, NML with the two-level model identified a significant moderation effect of race on the regression of job prestige on years of education while LS with the MMR model did not. An R package is also developed and documented to facilitate the application of the two-level model.

Management of pediatric patients with refractory constipation who fail cecostomy.

PubMed

Bonilla, Silvana F; Flores, Alejandro; Jackson, Carl-Christian A; Chwals, Walter J; Orkin, Bruce A

2013-09-01

Antegrade continence enema (ACE) is a recognized therapeutic option in the management of pediatric refractory constipation. Data on the long-term outcome of patients who fail to improve after an ACE-procedure are lacking. To describe the rate of ACE bowel management failure in pediatric refractory constipation, and the management and long term outcome of these patients. Retrospective analysis of a cohort of patients that underwent ACE-procedure and had at least 3-year-follow-up. Detailed analysis of subsequent treatment and outcome of those patients with a poor functional outcome was performed. 76 patients were included. 12 (16%) failed successful bowel management after ACE requiring additional intervention. Mean follow-up was 66.3 (range 35-95 months) after ACE-procedure. Colonic motility studies demonstrated colonic neuropathy in 7 patients (58%); abnormal motility in 4 patients (33%), and abnormal left-sided colonic motility in 1 patient (9%). All 12 patients were ultimately treated surgically. Nine patients (75%) had marked clinical improvement, whereas 3 patients (25%) continued to have poor function issues at long term follow-up. Colonic resection, either segmental or total, led to improvement or resolution of symptoms in the majority of patients who failed cecostomy. However, this is a complex and heterogeneous group and some patients will have continued issues. Copyright © 2013 Elsevier Inc. All rights reserved.

Bacterial plaque colonization around dental implant surfaces.

PubMed

Covani, Ugo; Marconcini, Simone; Crespi, Roberto; Barone, Antonio

2006-09-01

To examine the distribution of bacteria into the internal and external surfaces of failed implants using histologic analysis. There were 10 failed pure titanium and 5 failed hydroxyapatite-coated titanium implants consecutively removed various years after their placement. Criteria for fixture removal were peri-implant radiolucency and clinical mobility. The mobile fixtures were retrieved with the patients under local anesthesia. Fixtures were removed maintaining the abutments with the aim to observe the bacterial infiltration at the level of abutment/implant interface and on the implant surface. A thin radiolucent space was always present around all the failed implants. The abutments screws were tightly secured in all clinical cases. The bacterial cells were composed of cocci and filaments, which were adherent to the implant surface with an orientation perpendicular to the long axis of the implant. All the specimens included in this study showed bacteria at the level of implant/abutment interface. Histologic analysis at the level of abutment/implant interface in 2-stage implants identified heavy bacterial colonization. These findings appear to support those studies showing bacteria penetration at the level of the micro-gap, which can legitimate the hypothesis that the micro-gap at the bone level could present a risk for bone loss caused by bacterial colonization.

Nonlinear isochrones in murine left ventricular pressure-volume loops: how well does the time-varying elastance concept hold?

PubMed

Claessens, T E; Georgakopoulos, D; Afanasyeva, M; Vermeersch, S J; Millar, H D; Stergiopulos, N; Westerhof, N; Verdonck, P R; Segers, P

2006-04-01

The linear time-varying elastance theory is frequently used to describe the change in ventricular stiffness during the cardiac cycle. The concept assumes that all isochrones (i.e., curves that connect pressure-volume data occurring at the same time) are linear and have a common volume intercept. Of specific interest is the steepest isochrone, the end-systolic pressure-volume relationship (ESPVR), of which the slope serves as an index for cardiac contractile function. Pressure-volume measurements, achieved with a combined pressure-conductance catheter in the left ventricle of 13 open-chest anesthetized mice, showed a marked curvilinearity of the isochrones. We therefore analyzed the shape of the isochrones by using six regression algorithms (two linear, two quadratic, and two logarithmic, each with a fixed or time-varying intercept) and discussed the consequences for the elastance concept. Our main observations were 1) the volume intercept varies considerably with time; 2) isochrones are equally well described by using quadratic or logarithmic regression; 3) linear regression with a fixed intercept shows poor correlation (R(2) < 0.75) during isovolumic relaxation and early filling; and 4) logarithmic regression is superior in estimating the fixed volume intercept of the ESPVR. In conclusion, the linear time-varying elastance fails to provide a sufficiently robust model to account for changes in pressure and volume during the cardiac cycle in the mouse ventricle. A new framework accounting for the nonlinear shape of the isochrones needs to be developed.

Does Nonlinear Modeling Play a Role in Plasmid Bioprocess Monitoring Using Fourier Transform Infrared Spectra?

PubMed

Lopes, Marta B; Calado, Cecília R C; Figueiredo, Mário A T; Bioucas-Dias, José M

2017-06-01

The monitoring of biopharmaceutical products using Fourier transform infrared (FT-IR) spectroscopy relies on calibration techniques involving the acquisition of spectra of bioprocess samples along the process. The most commonly used method for that purpose is partial least squares (PLS) regression, under the assumption that a linear model is valid. Despite being successful in the presence of small nonlinearities, linear methods may fail in the presence of strong nonlinearities. This paper studies the potential usefulness of nonlinear regression methods for predicting, from in situ near-infrared (NIR) and mid-infrared (MIR) spectra acquired in high-throughput mode, biomass and plasmid concentrations in Escherichia coli DH5-α cultures producing the plasmid model pVAX-LacZ. The linear methods PLS and ridge regression (RR) are compared with their kernel (nonlinear) versions, kPLS and kRR, as well as with the (also nonlinear) relevance vector machine (RVM) and Gaussian process regression (GPR). For the systems studied, RR provided better predictive performances compared to the remaining methods. Moreover, the results point to further investigation based on larger data sets whenever differences in predictive accuracy between a linear method and its kernelized version could not be found. The use of nonlinear methods, however, shall be judged regarding the additional computational cost required to tune their additional parameters, especially when the less computationally demanding linear methods herein studied are able to successfully monitor the variables under study.

Multiple Correlation versus Multiple Regression.

ERIC Educational Resources Information Center

Huberty, Carl J.

2003-01-01

Describes differences between multiple correlation analysis (MCA) and multiple regression analysis (MRA), showing how these approaches involve different research questions and study designs, different inferential approaches, different analysis strategies, and different reported information. (SLD)

Functional Relationships and Regression Analysis.

ERIC Educational Resources Information Center

Preece, Peter F. W.

1978-01-01

Using a degenerate multivariate normal model for the distribution of organismic variables, the form of least-squares regression analysis required to estimate a linear functional relationship between variables is derived. It is suggested that the two conventional regression lines may be considered to describe functional, not merely statistical,…

Isolating and Examining Sources of Suppression and Multicollinearity in Multiple Linear Regression

ERIC Educational Resources Information Center

Beckstead, Jason W.

2012-01-01

The presence of suppression (and multicollinearity) in multiple regression analysis complicates interpretation of predictor-criterion relationships. The mathematical conditions that produce suppression in regression analysis have received considerable attention in the methodological literature but until now nothing in the way of an analytic…

General Nature of Multicollinearity in Multiple Regression Analysis.

ERIC Educational Resources Information Center

Liu, Richard

1981-01-01

Discusses multiple regression, a very popular statistical technique in the field of education. One of the basic assumptions in regression analysis requires that independent variables in the equation should not be highly correlated. The problem of multicollinearity and some of the solutions to it are discussed. (Author)

Logistic Regression: Concept and Application

ERIC Educational Resources Information Center

Cokluk, Omay

2010-01-01

The main focus of logistic regression analysis is classification of individuals in different groups. The aim of the present study is to explain basic concepts and processes of binary logistic regression analysis intended to determine the combination of independent variables which best explain the membership in certain groups called dichotomous…

Failure investigations of failed valve plug SS410 steel due to cracking

NASA Astrophysics Data System (ADS)

Kalyankar, V. D.; Deshmukh, D. D.

2017-12-01

Premature and sudden in service failure of a valve plug due to crack formation, applied in power plant has been investigated. The plug was tempered and heat treated, the crack was originated at centre, developed along the axis and propagates radially towards outer surface of plug. The expected life of the component is 10-15 years while, the component had failed just after the installation that is, within 3 months of its service. No corrosion products were observed on the crack interface and on the failed surface; hence, causes of corrosion failure are neglected. This plug of level separator control valve, is welded to the stem by means of plasma-transferred arc welding and as there is no crack observed at the welding zone, the failure due to welding residual stresses are also neglected. The failed component discloses exposed surface of a crack interface that originated from centre and propagates radially. The micro-structural observation, hardness testing, and visual observation are carried out of the specimen prepared from the failed section and base portion. The microstructure from the cracked interface showed severe carbide formation along the grain boundaries. From the microstructural analysis of the failed sample, it is observed that there is a formation of acicular carbides along the grain boundaries due to improper tempering heat treatment.

Time Spent Walking and Risk of Diabetes in Japanese Adults: The Japan Public Health Center-Based Prospective Diabetes Study

PubMed Central

Kabeya, Yusuke; Goto, Atsushi; Kato, Masayuki; Matsushita, Yumi; Takahashi, Yoshihiko; Isogawa, Akihiro; Inoue, Manami; Mizoue, Tetsuya; Tsugane, Shoichiro; Kadowaki, Takashi; Noda, Mitsuhiko

2016-01-01

Background The association between time spent walking and risk of diabetes was investigated in a Japanese population-based cohort. Methods Data from the Japan Public Health Center-based Prospective Diabetes cohort were analyzed. The surveys of diabetes were performed at baseline and at the 5-year follow-up. Time spent walking per day was assessed using a self-reported questionnaire (<30 minutes, 30 minutes to <1 hour, 1 to <2 hours, or ≥2 hours). A cross-sectional analysis was performed among 26 488 adults in the baseline survey. Logistic regression was used to examine the association between time spent walking and the presence of unrecognized diabetes. We then performed a longitudinal analysis that was restricted to 11 101 non-diabetic adults who participated in both the baseline and 5-year surveys. The association between time spent walking and the incidence of diabetes during the 5 years was examined. Results In the cross-sectional analysis, 1058 participants had unrecognized diabetes. Those with time spent walking of <30 minutes per day had increased odds of having diabetes in relation to those with time spent walking of ≥2 hours (adjusted odds ratio [OR] 1.23; 95% CI, 1.02–1.48). In the longitudinal analysis, 612 participants developed diabetes during the 5 years of follow-up. However, a significant association between time spent walking and the incidence of diabetes was not observed. Conclusions Increased risk of diabetes was implied in those with time spent walking of <30 minutes per day, although the longitudinal analysis failed to show a significant result. PMID:26725285

O6-Methylguanine-DNA methyltransferase protein expression by immunohistochemistry in brain and non-brain systemic tumours: systematic review and meta-analysis of correlation with methylation-specific polymerase chain reaction.

PubMed

Brell, Marta; Ibáñez, Javier; Tortosa, Avelina

2011-01-26

The DNA repair protein O6-Methylguanine-DNA methyltransferase (MGMT) confers resistance to alkylating agents. Several methods have been applied to its analysis, with methylation-specific polymerase chain reaction (MSP) the most commonly used for promoter methylation study, while immunohistochemistry (IHC) has become the most frequently used for the detection of MGMT protein expression. Agreement on the best and most reliable technique for evaluating MGMT status remains unsettled. The aim of this study was to perform a systematic review and meta-analysis of the correlation between IHC and MSP. A computer-aided search of MEDLINE (1950-October 2009), EBSCO (1966-October 2009) and EMBASE (1974-October 2009) was performed for relevant publications. Studies meeting inclusion criteria were those comparing MGMT protein expression by IHC with MGMT promoter methylation by MSP in the same cohort of patients. Methodological quality was assessed by using the QUADAS and STARD instruments. Previously published guidelines were followed for meta-analysis performance. Of 254 studies identified as eligible for full-text review, 52 (20.5%) met the inclusion criteria. The review showed that results of MGMT protein expression by IHC are not in close agreement with those obtained with MSP. Moreover, type of tumour (primary brain tumour vs others) was an independent covariate of accuracy estimates in the meta-regression analysis beyond the cut-off value. Protein expression assessed by IHC alone fails to reflect the promoter methylation status of MGMT. Thus, in attempts at clinical diagnosis the two methods seem to select different groups of patients and should not be used interchangeably.

Applying Regression Analysis to Problems in Institutional Research.

ERIC Educational Resources Information Center

Bohannon, Tom R.

1988-01-01

Regression analysis is one of the most frequently used statistical techniques in institutional research. Principles of least squares, model building, residual analysis, influence statistics, and multi-collinearity are described and illustrated. (Author/MSE)

Molecular characterization and expression profile of partial TLR4 gene in association to mastitis in crossbred cattle.

PubMed

Panigrahi, Manjit; Sharma, Arjava; Bhushan, Bharat

2014-01-01

Crossbred cattle are more prone to mastitis in comparison to indigenous cattle. Toll-like receptor 4 (TLR4) recognizes pathogen ligands, for example, lipopolysaccharide (LPS) endotoxin from Escherichia coli and mediates signaling to initiate innate and adaptive immune responses. Mutations in TLR4 can compromise the host immune response to certain pathogens, so it may be a potential candidate for marker assisted selection to enhance mastitis resistance in dairy cattle. Hence, in this study role of bovine TLR4 gene in mastitis resistance was investigated by association as well as expression profiling analysis in crossbred cattle. The animals were divided into mastitis affected and unaffected groups on the basis of history of animals and California Mastitis Test (CMT). PCR-SSCP and Sequence analysis revealed three genotypes of coreceptor binding region 1 (CRBR1) fragment of TLR4 gene namely AA, AB, and BB in both groups of cattle. The logistic regression model did not show any significant effect of these genotypes on the occurrence of clinical mastitis. Moreover, in vitro challenge of peripheral blood mononuclear cells (PBMCs) with LPS failed to show any association of the genotypes with TLR4 gene expression. In a nutshell, in the present study enough evidence was not found for association of the SNP variants of CRBR1 fragment of TLR4 gene with mastitis susceptibility in crossbred cattle.

CANcer-specific Evaluation System (CANES): a high-accuracy platform, for preclinical single/multi-biomarker discovery

PubMed Central

Kwon, Min-Seok; Nam, Seungyoon; Lee, Sungyoung; Ahn, Young Zoo; Chang, Hae Ryung; Kim, Yon Hui; Park, Taesung

2017-01-01

The recent creation of enormous, cancer-related “Big Data” public depositories represents a powerful means for understanding tumorigenesis. However, a consistently accurate system for clinically evaluating single/multi-biomarkers remains lacking, and it has been asserted that oft-failed clinical advancement of biomarkers occurs within the very early stages of biomarker assessment. To address these challenges, we developed a clinically testable, web-based tool, CANcer-specific single/multi-biomarker Evaluation System (CANES), to evaluate biomarker effectiveness, across 2,134 whole transcriptome datasets, from 94,147 biological samples (from 18 tumor types). For user-provided single/multi-biomarkers, CANES evaluates the performance of single/multi-biomarker candidates, based on four classification methods, support vector machine, random forest, neural networks, and classification and regression trees. In addition, CANES offers several advantages over earlier analysis tools, including: 1) survival analysis; 2) evaluation of mature miRNAs as markers for user-defined diagnostic or prognostic purposes; and 3) provision of a “pan-cancer” summary view, based on each single marker. We believe that such “landscape” evaluation of single/multi-biomarkers, for diagnostic therapeutic/prognostic decision-making, will be highly valuable for the discovery and “repurposing” of existing biomarkers (and their specific targeted therapies), leading to improved patient therapeutic stratification, a key component of targeted therapy success for the avoidance of therapy resistance. PMID:29050243

Investigating elementary principals' science beliefs and knowledge and its relationship to students' science outcomes

NASA Astrophysics Data System (ADS)

Khan, Uzma Zafar

The aim of this quantitative study was to investigate elementary principals' beliefs about reformed science teaching and learning, science subject matter knowledge, and how these factors relate to fourth grade students' superior science outcomes. Online survey methodology was used for data collection and included a demographic questionnaire and two survey instruments: the K-4 Physical Science Misconceptions Oriented Science Assessment Resources for Teachers (MOSART) and the Beliefs About Reformed Science Teaching and Learning (BARSTL). Hierarchical multiple regression analysis was used to assess the separate and collective contributions of background variables such as principals' personal and school characteristics, principals' science teaching and learning beliefs, and principals' science knowledge on students' superior science outcomes. Mediation analysis was also used to explore whether principals' science knowledge mediated the relationship between their beliefs about science teaching and learning and students' science outcomes. Findings indicated that principals' science beliefs and knowledge do not contribute to predicting students' superior science scores. Fifty-two percent of the variance in percentage of students with superior science scores was explained by school characteristics with free or reduced price lunch and school type as the only significant individual predictors. Furthermore, principals' science knowledge did not mediate the relationship between their science beliefs and students' science outcomes. There was no statistically significant variation among the variables. The data failed to support the proposed mediation model of the study. Implications for future research are discussed.

Success and duration of dynamic bracing for pectus carinatum: A four-year prospective study.

PubMed

Emil, Sherif; Sévigny, Marika; Montpetit, Kathleen; Baird, Robert; Laberge, Jean-Martin; Goyette, Jade; Finlay, Ian; Courchesne, Guylaine

2017-01-01

This study sought to establish factors that can prognosticate outcomes of bracing for pectus carinatum (PC). Prospective data were collected on all patients enrolled in a dynamic bracing protocol from July 2011 to July 2015. Pressure of correction (POC) was measured at initiation of treatment, and pressure of treatment (POT) was measured pre- and post-adjustment at every follow-up visit. Univariate and Cox regression analysis tested the following possible determinants of success and bracing duration: age, sex, symmetry, POC, and POT drop during the first two follow-up visits. Of 114 patients, 64 (56%) succeeded, 33 (29%) were still in active bracing, and 17 (15%) failed or were lost to follow-up. In successful patients, active and maintenance bracing was 5.66±3.81 and 8.80±3.94months, respectively. Asymmetry and older age were significantly associated with failure. Multivariable Cox proportional hazard analysis of time-to-maintenance showed that asymmetry (p=0.01) and smaller first drop in POT (p=0.02) were associated with longer time to reach maintenance. Pressure of correction does not predict failure of bracing, but older age, asymmetry, and smaller first drop in pressure of treatment are associated with failure and longer bracing duration. Prospective Study/Level of Evidence IV. Copyright © 2017 Elsevier Inc. All rights reserved.

The Empirical Review of Meta-Analysis Published in Korea

ERIC Educational Resources Information Center

Park, Sunyoung; Hong, Sehee

2016-01-01

Meta-analysis is a statistical method that is increasingly utilized to combine and compare the results of previous primary studies. However, because of the lack of comprehensive guidelines for how to use meta-analysis, many meta-analysis studies have failed to consider important aspects, such as statistical programs, power analysis, publication…

Multicollinearity in Regression Analyses Conducted in Epidemiologic Studies

PubMed Central

Vatcheva, Kristina P.; Lee, MinJae; McCormick, Joseph B.; Rahbar, Mohammad H.

2016-01-01

The adverse impact of ignoring multicollinearity on findings and data interpretation in regression analysis is very well documented in the statistical literature. The failure to identify and report multicollinearity could result in misleading interpretations of the results. A review of epidemiological literature in PubMed from January 2004 to December 2013, illustrated the need for a greater attention to identifying and minimizing the effect of multicollinearity in analysis of data from epidemiologic studies. We used simulated datasets and real life data from the Cameron County Hispanic Cohort to demonstrate the adverse effects of multicollinearity in the regression analysis and encourage researchers to consider the diagnostic for multicollinearity as one of the steps in regression analysis. PMID:27274911

Multicollinearity in Regression Analyses Conducted in Epidemiologic Studies.

PubMed

Vatcheva, Kristina P; Lee, MinJae; McCormick, Joseph B; Rahbar, Mohammad H

2016-04-01

The adverse impact of ignoring multicollinearity on findings and data interpretation in regression analysis is very well documented in the statistical literature. The failure to identify and report multicollinearity could result in misleading interpretations of the results. A review of epidemiological literature in PubMed from January 2004 to December 2013, illustrated the need for a greater attention to identifying and minimizing the effect of multicollinearity in analysis of data from epidemiologic studies. We used simulated datasets and real life data from the Cameron County Hispanic Cohort to demonstrate the adverse effects of multicollinearity in the regression analysis and encourage researchers to consider the diagnostic for multicollinearity as one of the steps in regression analysis.

[Fatigue damage analysis of porcelain in all-ceramic crowns].

PubMed

Liu, Yi-hong; Feng, Hai-lan; Liu, Guang-hua; Shen, Zhi-jian

2010-02-18

To investigate the fatigue damage mechanism of porcelain, and its relation with the microscopic defects in clinically failed all-ceramic crowns. Collecting the bilayered all-ceramic crowns failed in vivo. The fractured surfaces and occlusial surfaces of failed crowns were examined by an optical microscope followed by detailed fractography investigations using a field emission scanning electron microscope. When chemical impurities were of concern, energy-dispersive X-ray spectroscopy analysis was performed to examine chemical composition. A standard practice for fractography failure analysis of advanced ceramics is applied to disclose the fracture mode, and damage character. Three types of fracture features are defined as breakdown of the entire crown, and porcelain chipping-off/delamination. Alumina crowns were usually characterized by breakdown of the entire crown, while zirconia crowns by porcelain chipping-off and delamination. The fatigue damage of porcelain was classified into surface wear, cone crack, and porcelain delamination. The observed microscopic defects in this study included air bubbles and impurity particles. The multi-point occlusial contacts were recommended in all-ceramic restorations clinically. The thickness of porcelain is important for the anti-fatigue ability of porcelain. Cautions have to be taken to avoid contaminations during the veneering processes.

GPU-accelerated Kernel Regression Reconstruction for Freehand 3D Ultrasound Imaging.

PubMed

Wen, Tiexiang; Li, Ling; Zhu, Qingsong; Qin, Wenjian; Gu, Jia; Yang, Feng; Xie, Yaoqin

2017-07-01

Volume reconstruction method plays an important role in improving reconstructed volumetric image quality for freehand three-dimensional (3D) ultrasound imaging. By utilizing the capability of programmable graphics processing unit (GPU), we can achieve a real-time incremental volume reconstruction at a speed of 25-50 frames per second (fps). After incremental reconstruction and visualization, hole-filling is performed on GPU to fill remaining empty voxels. However, traditional pixel nearest neighbor-based hole-filling fails to reconstruct volume with high image quality. On the contrary, the kernel regression provides an accurate volume reconstruction method for 3D ultrasound imaging but with the cost of heavy computational complexity. In this paper, a GPU-based fast kernel regression method is proposed for high-quality volume after the incremental reconstruction of freehand ultrasound. The experimental results show that improved image quality for speckle reduction and details preservation can be obtained with the parameter setting of kernel window size of [Formula: see text] and kernel bandwidth of 1.0. The computational performance of the proposed GPU-based method can be over 200 times faster than that on central processing unit (CPU), and the volume with size of 50 million voxels in our experiment can be reconstructed within 10 seconds.

Stepwise versus Hierarchical Regression: Pros and Cons

ERIC Educational Resources Information Center

Lewis, Mitzi

2007-01-01

Multiple regression is commonly used in social and behavioral data analysis. In multiple regression contexts, researchers are very often interested in determining the "best" predictors in the analysis. This focus may stem from a need to identify those predictors that are supportive of theory. Alternatively, the researcher may simply be interested…

Interpreting Bivariate Regression Coefficients: Going beyond the Average

ERIC Educational Resources Information Center

Halcoussis, Dennis; Phillips, G. Michael

2010-01-01

Statistics, econometrics, investment analysis, and data analysis classes often review the calculation of several types of averages, including the arithmetic mean, geometric mean, harmonic mean, and various weighted averages. This note shows how each of these can be computed using a basic regression framework. By recognizing when a regression model…

Regression Commonality Analysis: A Technique for Quantitative Theory Building

ERIC Educational Resources Information Center

Nimon, Kim; Reio, Thomas G., Jr.

2011-01-01

When it comes to multiple linear regression analysis (MLR), it is common for social and behavioral science researchers to rely predominately on beta weights when evaluating how predictors contribute to a regression model. Presenting an underutilized statistical technique, this article describes how organizational researchers can use commonality…

Precision Efficacy Analysis for Regression.

ERIC Educational Resources Information Center

Brooks, Gordon P.

When multiple linear regression is used to develop a prediction model, sample size must be large enough to ensure stable coefficients. If the derivation sample size is inadequate, the model may not predict well for future subjects. The precision efficacy analysis for regression (PEAR) method uses a cross- validity approach to select sample sizes…

Performance of bias-correction methods for exposure measurement error using repeated measurements with and without missing data.

PubMed

Batistatou, Evridiki; McNamee, Roseanne

2012-12-10

It is known that measurement error leads to bias in assessing exposure effects, which can however, be corrected if independent replicates are available. For expensive replicates, two-stage (2S) studies that produce data 'missing by design', may be preferred over a single-stage (1S) study, because in the second stage, measurement of replicates is restricted to a sample of first-stage subjects. Motivated by an occupational study on the acute effect of carbon black exposure on respiratory morbidity, we compare the performance of several bias-correction methods for both designs in a simulation study: an instrumental variable method (EVROS IV) based on grouping strategies, which had been recommended especially when measurement error is large, the regression calibration and the simulation extrapolation methods. For the 2S design, either the problem of 'missing' data was ignored or the 'missing' data were imputed using multiple imputations. Both in 1S and 2S designs, in the case of small or moderate measurement error, regression calibration was shown to be the preferred approach in terms of root mean square error. For 2S designs, regression calibration as implemented by Stata software is not recommended in contrast to our implementation of this method; the 'problematic' implementation of regression calibration although substantially improved with use of multiple imputations. The EVROS IV method, under a good/fairly good grouping, outperforms the regression calibration approach in both design scenarios when exposure mismeasurement is severe. Both in 1S and 2S designs with moderate or large measurement error, simulation extrapolation severely failed to correct for bias. Copyright © 2012 John Wiley & Sons, Ltd.

Cell Death and Reproductive Regression in Female Schistosoma mansoni

PubMed Central

Galanti, Sarah E.; Huang, Stanley Ching-Cheng; Pearce, Edward J.

2012-01-01

The vitellarium is a highly proliferative organ, producing cells which are incorporated along with a fertilized ovum into the schistosome egg. Vitellarial growth fails to occur in virgin female schistosomes in single sex (female-only) infections, and involution of this tissue, which is accompanied by physical shrinkage of the entire worm, occurs when mature females sexually regress upon removal from their male partners. We have found that upon removal from their hosts into tissue culture, female parasites regress whether they are mated or not, but that cessation of egg production and a decline in expression of the vitelline gene p14 is delayed by mating. We used BrdU labeling to investigate whether there was a loss of proliferation in the vittelarium that might account for regression and found that the proliferation rate declined equally in paired and singled females once placed into culture. However, TUNEL staining and Caspase 3 activity measurements indicate that the loss of vitrellarial cellularity associated with regression is associated with profound apoptotic vitelline cell death, which is not apparent in the vitellaria of paired females immediately ex vivo, and which develops in vitro regardless of whether males are present or not. Furthermore, primordial vitellaria in virgin females have a high frequency of apoptotic cells but are characterized by a proliferation rate that is indistinguishable from that in fully developed vitellaria in mature paired females. Taken together, our data suggest that the vitelline proliferation rate is independent of pairing status. In contrast, the survival of vitelline cells, and therefore the development of the vitellarium, is highly male-dependent. Both processes are negatively affected by removal from the host regardless of whether male worms are present or not, and are unsustainable using standard tissue culture approaches. PMID:22363825

Estimation of 1RM for knee extension based on the maximal isometric muscle strength and body composition.

PubMed

Kanada, Yoshikiyo; Sakurai, Hiroaki; Sugiura, Yoshito; Arai, Tomoaki; Koyama, Soichiro; Tanabe, Shigeo

2017-11-01

[Purpose] To create a regression formula in order to estimate 1RM for knee extensors, based on the maximal isometric muscle strength measured using a hand-held dynamometer and data regarding the body composition. [Subjects and Methods] Measurement was performed in 21 healthy males in their twenties to thirties. Single regression analysis was performed, with measurement values representing 1RM and the maximal isometric muscle strength as dependent and independent variables, respectively. Furthermore, multiple regression analysis was performed, with data regarding the body composition incorporated as another independent variable, in addition to the maximal isometric muscle strength. [Results] Through single regression analysis with the maximal isometric muscle strength as an independent variable, the following regression formula was created: 1RM (kg)=0.714 + 0.783 × maximal isometric muscle strength (kgf). On multiple regression analysis, only the total muscle mass was extracted. [Conclusion] A highly accurate regression formula to estimate 1RM was created based on both the maximal isometric muscle strength and body composition. Using a hand-held dynamometer and body composition analyzer, it was possible to measure these items in a short time, and obtain clinically useful results.

Regression Model Optimization for the Analysis of Experimental Data

NASA Technical Reports Server (NTRS)

Ulbrich, N.

2009-01-01

A candidate math model search algorithm was developed at Ames Research Center that determines a recommended math model for the multivariate regression analysis of experimental data. The search algorithm is applicable to classical regression analysis problems as well as wind tunnel strain gage balance calibration analysis applications. The algorithm compares the predictive capability of different regression models using the standard deviation of the PRESS residuals of the responses as a search metric. This search metric is minimized during the search. Singular value decomposition is used during the search to reject math models that lead to a singular solution of the regression analysis problem. Two threshold dependent constraints are also applied. The first constraint rejects math models with insignificant terms. The second constraint rejects math models with near-linear dependencies between terms. The math term hierarchy rule may also be applied as an optional constraint during or after the candidate math model search. The final term selection of the recommended math model depends on the regressor and response values of the data set, the user s function class combination choice, the user s constraint selections, and the result of the search metric minimization. A frequently used regression analysis example from the literature is used to illustrate the application of the search algorithm to experimental data.

[Application of negative binomial regression and modified Poisson regression in the research of risk factors for injury frequency].

PubMed

Cao, Qingqing; Wu, Zhenqiang; Sun, Ying; Wang, Tiezhu; Han, Tengwei; Gu, Chaomei; Sun, Yehuan

2011-11-01

To Eexplore the application of negative binomial regression and modified Poisson regression analysis in analyzing the influential factors for injury frequency and the risk factors leading to the increase of injury frequency. 2917 primary and secondary school students were selected from Hefei by cluster random sampling method and surveyed by questionnaire. The data on the count event-based injuries used to fitted modified Poisson regression and negative binomial regression model. The risk factors incurring the increase of unintentional injury frequency for juvenile students was explored, so as to probe the efficiency of these two models in studying the influential factors for injury frequency. The Poisson model existed over-dispersion (P < 0.0001) based on testing by the Lagrangemultiplier. Therefore, the over-dispersion dispersed data using a modified Poisson regression and negative binomial regression model, was fitted better. respectively. Both showed that male gender, younger age, father working outside of the hometown, the level of the guardian being above junior high school and smoking might be the results of higher injury frequencies. On a tendency of clustered frequency data on injury event, both the modified Poisson regression analysis and negative binomial regression analysis can be used. However, based on our data, the modified Poisson regression fitted better and this model could give a more accurate interpretation of relevant factors affecting the frequency of injury.

Logistic regression analysis of conventional ultrasonography, strain elastosonography, and contrast-enhanced ultrasound characteristics for the differentiation of benign and malignant thyroid nodules

PubMed Central

Deng, Yingyuan; Wang, Tianfu; Chen, Siping; Liu, Weixiang

2017-01-01

The aim of the study is to screen the significant sonographic features by logistic regression analysis and fit a model to diagnose thyroid nodules. A total of 525 pathological thyroid nodules were retrospectively analyzed. All the nodules underwent conventional ultrasonography (US), strain elastosonography (SE), and contrast -enhanced ultrasound (CEUS). Those nodules’ 12 suspicious sonographic features were used to assess thyroid nodules. The significant features of diagnosing thyroid nodules were picked out by logistic regression analysis. All variables that were statistically related to diagnosis of thyroid nodules, at a level of p < 0.05 were embodied in a logistic regression analysis model. The significant features in the logistic regression model of diagnosing thyroid nodules were calcification, suspected cervical lymph node metastasis, hypoenhancement pattern, margin, shape, vascularity, posterior acoustic, echogenicity, and elastography score. According to the results of logistic regression analysis, the formula that could predict whether or not thyroid nodules are malignant was established. The area under the receiver operating curve (ROC) was 0.930 and the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were 83.77%, 89.56%, 87.05%, 86.04%, and 87.79% respectively. PMID:29228030

Logistic regression analysis of conventional ultrasonography, strain elastosonography, and contrast-enhanced ultrasound characteristics for the differentiation of benign and malignant thyroid nodules.

PubMed

Pang, Tiantian; Huang, Leidan; Deng, Yingyuan; Wang, Tianfu; Chen, Siping; Gong, Xuehao; Liu, Weixiang

2017-01-01

The aim of the study is to screen the significant sonographic features by logistic regression analysis and fit a model to diagnose thyroid nodules. A total of 525 pathological thyroid nodules were retrospectively analyzed. All the nodules underwent conventional ultrasonography (US), strain elastosonography (SE), and contrast -enhanced ultrasound (CEUS). Those nodules' 12 suspicious sonographic features were used to assess thyroid nodules. The significant features of diagnosing thyroid nodules were picked out by logistic regression analysis. All variables that were statistically related to diagnosis of thyroid nodules, at a level of p < 0.05 were embodied in a logistic regression analysis model. The significant features in the logistic regression model of diagnosing thyroid nodules were calcification, suspected cervical lymph node metastasis, hypoenhancement pattern, margin, shape, vascularity, posterior acoustic, echogenicity, and elastography score. According to the results of logistic regression analysis, the formula that could predict whether or not thyroid nodules are malignant was established. The area under the receiver operating curve (ROC) was 0.930 and the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were 83.77%, 89.56%, 87.05%, 86.04%, and 87.79% respectively.

Optimisation in the Design of Environmental Sensor Networks with Robustness Consideration

PubMed Central

Budi, Setia; de Souza, Paulo; Timms, Greg; Malhotra, Vishv; Turner, Paul

2015-01-01

This work proposes the design of Environmental Sensor Networks (ESN) through balancing robustness and redundancy. An Evolutionary Algorithm (EA) is employed to find the optimal placement of sensor nodes in the Region of Interest (RoI). Data quality issues are introduced to simulate their impact on the performance of the ESN. Spatial Regression Test (SRT) is also utilised to promote robustness in data quality of the designed ESN. The proposed method provides high network representativeness (fit for purpose) with minimum sensor redundancy (cost), and ensures robustness by enabling the network to continue to achieve its objectives when some sensors fail. PMID:26633392

A molecular diagnostic test for persistent Müllerian duct syndrome in miniature schnauzer dogs.

PubMed

Pujar, S; Meyers-Wallen, V N

2009-01-01

In persistent Müllerian duct syndrome (PMDS), Müllerian ducts fail to regress in males during sexual differentiation. In the canine miniature schnauzer model, PMDS is caused by a C to T transition in exon 3 of the Müllerian inhibiting substance type II receptor (MISRII), which introduces a DdeI restriction site. Here we report a molecular diagnostic test for PMDS in the miniature schnauzer to identify affected dogs and carriers. As our test results suggest that the mutation is identical by descent in affected dogs of this breed, the test could be used to eliminate this mutation from the miniature schnauzer breed worldwide.

[Long-term treatment of Cushing's disease using ketoconazole. Possibility of therapeutic escape].

PubMed

Diop, S N; Warnet, A; Duet, M; Firmin, C; Mosse, A; Lubetzki, J

Five women suffering from Cushing's disease were treated with ketoconazole 800 mg per day for 2 to 28 months (mean 12.4 months). Four of them had full clinical and biochemical regression. However, after 8 months of therapy the disease failed to respond in three of these four women. Increasing the ketoconazole dosage up to 1,200 mg per day was ineffective in two patients. Such an escape phenomenon, not described until now, will restrict the use of ketoconazole in the treatment of Cushing's disease, although the drug is easy to administer and well tolerated globally and by the liver in most cases.

Why campaigns for local transportation funding initiatives succeed or fail : an analysis of four communities and national data

DOT National Transportation Integrated Search

2000-06-01

This report uses statistical analysis of community-level characteristics and qualitatively focused case studies to explore what determines the success of local transportation-related tax measures. The report contains both a statistical analysis of lo...

Fractographic ceramic failure analysis using the replica technique

PubMed Central

Scherrer, Susanne S.; Quinn, Janet B.; Quinn, George D.; Anselm Wiskott, H. W.

2007-01-01

Objectives To demonstrate the effectiveness of in vivo replicas of fractured ceramic surfaces for descriptive fractography as applied to the analysis of clinical failures. Methods The fracture surface topography of partially failed veneering ceramic of a Procera Alumina molar and an In Ceram Zirconia premolar were examined utilizing gold-coated epoxy poured replicas viewed using scanning electron microscopy. The replicas were inspected for fractographic features such as hackle, wake hackle, twist hackle, compression curl and arrest lines for determination of the direction of crack propagation and location of the origin. Results For both veneering ceramics, replicas provided an excellent reproduction of the fractured surfaces. Fine details including all characteristic fracture features produced by the interaction of the advancing crack with the material's microstructure could be recognized. The observed features are indicators of the local direction of crack propagation and were used to trace the crack's progression back to its initial starting zone (the origin). Drawbacks of replicas such as artifacts (air bubbles) or imperfections resulting from inadequate epoxy pouring were noted but not critical for the overall analysis of the fractured surfaces. Significance The replica technique proved to be easy to use and allowed an excellent reproduction of failed ceramic surfaces. It should be applied before attempting to remove any failed part remaining in situ as the fracture surface may be damaged during this procedure. These two case studies are intended as an introduction for the clinical researcher in using qualitative (descriptive) fractography as a tool for understanding fracture processes in brittle restorative materials and, secondarily, to draw conclusions as to possible design inadequacies in failed restorations. PMID:17270267

Failure Analysis of PRDS Pipe in a Thermal Power Plant Boiler

NASA Astrophysics Data System (ADS)

Ghosh, Debashis; Ray, Subrata; Mandal, Jiten; Mandal, Nilrudra; Shukla, Awdhesh Kumar

2018-04-01

The pressure reducer desuperheater (PRDS) pipeline is used for reducing the pressure and desuperheating of the steam in different auxiliary pipeline. When the PRDS pipeline is failed, the reliability of the boiler is affected. This paper investigates the probable cause/causes of failure of the PRDS tapping line. In that context, visual inspection, outside diameter and wall thickness measurement, chemical analysis, metallographic examination and hardness measurement are conducted as part of the investigative studies. Apart from these tests, mechanical testing and fractographic analysis are also conducted as supplements. Finally, it has been concluded that the PRDS pipeline has mainly failed due to graphitization due to prolonged exposure of the pipe at higher temperature. The improper material used is mainly responsible for premature failure of the pipe.

Destructive physical analysis results of Ni/H2 cells cycled in LEO regime

NASA Technical Reports Server (NTRS)

Lim, Hong S.; Zelter, Gabriela R.; Smithrick, John J.; Hall, Stephen W.

1991-01-01

Six 48-Ah individual pressure vessel (IPV) Ni/H2 cells containing 26 and 31 percent KOH electrolyte were life cycle tested in low Earth orbit. All three cells containing 31 percent KOH failed (3729, 4165, and 11,355 cycles), while those with 26 percent KOH were cycled over 14,000 times in the continuing test. Destructive physical analysis (DPA) of the failed cells included visual inspections, measurements of electrode thickness, scanning electron microscopy, chemical analysis, and measurements of nickel electrode capacity in an electrolyte flooded cell. The cycling failure was due to a decrease of nickel electrode capacity. As possible causes of the capacity decrease, researchers observed electrode expansion, rupture, and corrosion of the nickel electrode substrate, active material redistribution, and accumulation of electrochemically undischargeable active material with cycling.

Intensification of Diabetes Therapy and Time Until A1C Goal Attainment Among Patients With Newly Diagnosed Type 2 Diabetes Who Fail Metformin Monotherapy Within a Large Integrated Health System.

PubMed

Pantalone, Kevin M; Wells, Brian J; Chagin, Kevin M; Ejzykowicz, Flavia; Yu, Changhong; Milinovich, Alex; Bauman, Janine M; Kattan, Michael W; Rajpathak, Swapnil; Zimmerman, Robert S

2016-09-01

"Clinical inertia" has been used to describe the delay in the intensification of type 2 diabetes treatment among patients with poor glycemic control. Previous studies may have exaggerated the prevalence of clinical inertia by failing to adequately monitor drug dose changes and nonmedication interventions. This project evaluated the intensification of diabetes therapy and hemoglobin A1c (A1C) goal attainment among patients with newly diagnosed type 2 diabetes when metformin monotherapy failed. The electronic health record at Cleveland Clinic was used to identify patients with newly diagnosed type 2 diabetes between 2005 and 2013 who failed to reach the A1C goal after 3 months of metformin monotherapy. A time-dependent survival analysis was used to compare the time until A1C goal attainment in patients who received early intensification of therapy (within 6 months of metformin failure) or late intensification. The analysis was performed for A1C goals of 7% (n = 1,168), 7.5% (n = 679), and 8% (n = 429). Treatment was intensified early in 62%, 69%, and 72% of patients when poor glycemic control was defined as an A1C >7%, >7.5%, and >8%, respectively. The probability of undergoing an early intensification was greater the higher the A1C category. Time until A1C goal attainment was shorter among patients who received early intensification regardless of the A1C goal (all P < 0.05). A substantial number of patients with newly diagnosed type 2 diabetes fail to undergo intensification of therapy within 6 months of metformin monotherapy failure. Early intervention in patients when metformin monotherapy failed resulted in more rapid attainment of A1C goals. © 2016 by the American Diabetes Association.

Deep RNA sequencing reveals dynamic regulation of myocardial noncoding RNAs in failing human heart and remodeling with mechanical circulatory support.

PubMed

Yang, Kai-Chien; Yamada, Kathryn A; Patel, Akshar Y; Topkara, Veli K; George, Isaac; Cheema, Faisal H; Ewald, Gregory A; Mann, Douglas L; Nerbonne, Jeanne M

2014-03-04

Microarrays have been used extensively to profile transcriptome remodeling in failing human heart, although the genomic coverage provided is limited and fails to provide a detailed picture of the myocardial transcriptome landscape. Here, we describe sequencing-based transcriptome profiling, providing comprehensive analysis of myocardial mRNA, microRNA (miRNA), and long noncoding RNA (lncRNA) expression in failing human heart before and after mechanical support with a left ventricular (LV) assist device (LVAD). Deep sequencing of RNA isolated from paired nonischemic (NICM; n=8) and ischemic (ICM; n=8) human failing LV samples collected before and after LVAD and from nonfailing human LV (n=8) was conducted. These analyses revealed high abundance of mRNA (37%) and lncRNA (71%) of mitochondrial origin. miRNASeq revealed 160 and 147 differentially expressed miRNAs in ICM and NICM, respectively, compared with nonfailing LV. Among these, only 2 (ICM) and 5 (NICM) miRNAs are normalized with LVAD. RNASeq detected 18 480, including 113 novel, lncRNAs in human LV. Among the 679 (ICM) and 570 (NICM) lncRNAs differentially expressed with heart failure, ≈10% are improved or normalized with LVAD. In addition, the expression signature of lncRNAs, but not miRNAs or mRNAs, distinguishes ICM from NICM. Further analysis suggests that cis-gene regulation represents a major mechanism of action of human cardiac lncRNAs. The myocardial transcriptome is dynamically regulated in advanced heart failure and after LVAD support. The expression profiles of lncRNAs, but not mRNAs or miRNAs, can discriminate failing hearts of different pathologies and are markedly altered in response to LVAD support. These results suggest an important role for lncRNAs in the pathogenesis of heart failure and in reverse remodeling observed with mechanical support.

SU-E-T-479: IMRT Plan Recalculation in Patient Based On Dynalog Data and the Effect of a Single Failing MLC Motor

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

Morcos, M; Mitrou, E

2015-06-15

Purpose: Using Linac dynamic logs (Dynalogs) we evaluate the impact of a single failing MLC motor on the deliverability of an IMRT plan by assessing the recalculated dose volume histograms (DVHs) taking the delivered MLC positions and beam hold-offs into consideration. Methods: This is a retrospective study based on a deteriorating MLC motor (leaf 36B) which was observed to be failing via Dynalog analysis. To investigate further, Eclipse-importable MLC files were generated from Dynalogs to recalculate the actual delivered dose and to assess the clinical impact through DVHs. All deliveries were performed on a Varian 21EX linear accelerator equipped withmore » Millennium-120 MLC. The analysis of Dynalog files and subsequent conversion to Eclipse-importable MLC files were all performed by in-house programming in Python. Effects on plan DVH are presented in the following section on a particular brain-IMRT plan which was delivered with a failing MLC motor which was then replaced. Results: Global max dose increased by 13.5%, max dose to the brainstem PRV increased by 8.2%, max dose to the optic chiasm increased by 7.6%, max dose to optic nerve increased by 8.8% and the mean dose to the PTV increased by 7.9% when comparing the original plan to the fraction with the failing MLC motor. The reason the dose increased was due to the failure being on the B-bank which is the lagging side on a sliding window delivery, therefore any failures on this side will cause an over-irradiation as the B-bank leaves struggles to keep the window from growing. Conclusion: Our findings suggest that a single failing MLC motor may jeopardize the entire delivery. This may be due to the bad MLC motor drawing too much current causing all MLCs on the same bank to underperform. This hypothesis will be investigated in a future study.« less

Patterns of medicinal plant use: an examination of the Ecuadorian Shuar medicinal flora using contingency table and binomial analyses.

PubMed

Bennett, Bradley C; Husby, Chad E

2008-03-28

Botanical pharmacopoeias are non-random subsets of floras, with some taxonomic groups over- or under-represented. Moerman [Moerman, D.E., 1979. Symbols and selectivity: a statistical analysis of Native American medical ethnobotany, Journal of Ethnopharmacology 1, 111-119] introduced linear regression/residual analysis to examine these patterns. However, regression, the commonly-employed analysis, suffers from several statistical flaws. We use contingency table and binomial analyses to examine patterns of Shuar medicinal plant use (from Amazonian Ecuador). We first analyzed the Shuar data using Moerman's approach, modified to better meet requirements of linear regression analysis. Second, we assessed the exact randomization contingency table test for goodness of fit. Third, we developed a binomial model to test for non-random selection of plants in individual families. Modified regression models (which accommodated assumptions of linear regression) reduced R(2) to from 0.59 to 0.38, but did not eliminate all problems associated with regression analyses. Contingency table analyses revealed that the entire flora departs from the null model of equal proportions of medicinal plants in all families. In the binomial analysis, only 10 angiosperm families (of 115) differed significantly from the null model. These 10 families are largely responsible for patterns seen at higher taxonomic levels. Contingency table and binomial analyses offer an easy and statistically valid alternative to the regression approach.

Predictors of restraint use among child occupants.

PubMed

Benedetti, Marco; Klinich, Kathleen D; Manary, Miriam A; Flannagan, Carol A

2017-11-17

The objective of this study was to identify factors that predict restraint use and optimal restraint use among children aged 0 to 13 years. The data set is a national sample of police-reported crashes for years 2010-2014 in which type of child restraint is recorded. The data set was supplemented with demographic census data linked by driver ZIP code, as well as a score for the state child restraint law during the year of the crash relative to best practice recommendations for protecting child occupants. Analysis used linear regression techniques. The main predictor of unrestrained child occupants was the presence of an unrestrained driver. Among restrained children, children had 1.66 (95% confidence interval, 1.27, 2.17) times higher odds of using the recommended type of restraint system if the state law at the time of the crash included requirements based on best practice recommendations. Children are more likely to ride in the recommended type of child restraint when their state's child restraint law includes wording that follows best practice recommendations for child occupant protection. However, state child restraint law requirements do not influence when caregivers fail to use an occupant restraint for their child passengers.

Catastrophic Health Expenditure and Rural Household Impoverishment in China: What Role Does the New Cooperative Health Insurance Scheme Play?

PubMed Central

Wu, Qunhong; Liu, Chaojie; Jiao, Mingli; Liu, Guoxiang; Hao, Yanhua; Ning, Ning

2014-01-01

Objective To determine whether the New Cooperative Medical Insurance Scheme (NCMS) is associated with decreased levels of catastrophic health expenditure and reduced impoverishment due to medical expenses in rural households of China. Methods An analysis of a national representative sample of 38,945 rural households (129,635 people) from the 2008 National Health Service Survey was performed. Logistic regression models used binary indicator of catastrophic health expenditure as dependent variable, with household consumption, demographic characteristics, health insurance schemes, and chronic illness as independent variables. Results Higher percentage of households experiencing catastrophic health expenditure and medical impoverishment correlates to increased health care need. While the higher socio-economic status households had similar levels of catastrophic health expenditure as compared with the lowest. Households covered by the NCMS had similar levels of catastrophic health expenditure and medical impoverishment as those without health insurance. Conclusion Despite over 95% of coverage, the NCMS has failed to prevent catastrophic health expenditure and medical impoverishment. An upgrade of benefit packages is needed, and effective cost control mechanisms on the provider side needs to be considered. PMID:24714605

Some See It, Some Don’t: Exploring the Relation between Inattentional Blindness and Personality Factors

PubMed Central

Kreitz, Carina; Schnuerch, Robert; Gibbons, Henning; Memmert, Daniel

2015-01-01

Human awareness is highly limited, which is vividly demonstrated by the phenomenon that unexpected objects go unnoticed when attention is focused elsewhere (inattentional blindness). Typically, some people fail to notice unexpected objects while others detect them instantaneously. Whether this pattern reflects stable individual differences is unclear to date. In particular, hardly anything is known about the influence of personality on the likelihood of inattentional blindness. To fill this empirical gap, we examined the role of multiple personality factors, namely the Big Five, BIS/BAS, absorption, achievement motivation, and schizotypy, in these failures of awareness. In a large-scale sample (N = 554), susceptibility to inattentional blindness was associated with a low level of openness to experience and marginally with a low level of achievement motivation. However, in a multiple regression analysis, only openness emerged as an independent, negative predictor. This suggests that the general tendency to be open to experience extends to the domain of perception. Our results complement earlier work on the possible link between inattentional blindness and personality by demonstrating, for the first time, that failures to consciously perceive unexpected objects reflect individual differences on a fundamental dimension of personality. PMID:26011567

Crop area estimation using high and medium resolution satellite imagery in areas with complex topography

USGS Publications Warehouse

Husak, G.J.; Marshall, M. T.; Michaelsen, J.; Pedreros, Diego; Funk, Christopher C.; Galu, G.

2008-01-01

Reliable estimates of cropped area (CA) in developing countries with chronic food shortages are essential for emergency relief and the design of appropriate market-based food security programs. Satellite interpretation of CA is an effective alternative to extensive and costly field surveys, which fail to represent the spatial heterogeneity at the country-level. Bias-corrected, texture based classifications show little deviation from actual crop inventories, when estimates derived from aerial photographs or field measurements are used to remove systematic errors in medium resolution estimates. In this paper, we demonstrate a hybrid high-medium resolution technique for Central Ethiopia that combines spatially limited unbiased estimates from IKONOS images, with spatially extensive Landsat ETM+ interpretations, land-cover, and SRTM-based topography. Logistic regression is used to derive the probability of a location being crop. These individual points are then aggregated to produce regional estimates of CA. District-level analysis of Landsat based estimates showed CA totals which supported the estimates of the Bureau of Agriculture and Rural Development. Continued work will evaluate the technique in other parts of Africa, while segmentation algorithms will be evaluated, in order to automate classification of medium resolution imagery for routine CA estimation in the future.

American export control, technology spillover and innovation of Chinese pharmaceutical Industry.

PubMed

Hui, Jiang

2017-05-01

This paper was aimed to analyze whether the U.S. strict export control to China affects the technological innovation of Chinese pharmaceutical industry. This paper selected the data of technological innovation and the expenditure of high and new technology adoption in China's pharmaceutical industry from 1995 to 2014, created panel regression model to study the impact of export controls on technology spillovers and the impact of technology spillovers on innovation capacity. The results show that US export control has a significant impact on technology spillovers, but foreign technology spillovers have no significant impact on the innovation of Chinese pharmaceutical industry. Although the US export control prevented foreign technology spillovers to China, but indirectly stimulated the domestic technology spillovers to pharmaceutical manufacturing industry in China. Statistical analysis show that the correlation coefficient between innovation capacity and expenditure for high technology adoption is not significant, but the expenditure of purchasing domestic technical is essential to pharmaceutical innovation. This study shows that US export control indirectly, not directly, affected the technological innovation of China's pharmaceutical industry, affected the allocation of innovative resources, but failed to prevent the technological progress and competitiveness improvement of Chinese pharmaceutical industry.

Attachment style and treatment completion among psychiatric inpatients with substance use disorders.

PubMed

Fowler, James Christopher; Groat, Michael; Ulanday, Mike

2013-01-01

A strong dose-response relationship exists for psychosocial treatments for co-morbid substance abuse disorders; yet rates of attrition are exceedingly high for those seeking treatment in residential and hospital settings. This study examined patient characteristics, including attachment style as predictors of completing 42 contiguous days of inpatient dual-diagnosis treatment among patients with substance use disorders. Baseline characteristics were assessed in 187 consecutively admitted patients with research diagnosis of substance use disorders. Hierarchical logistic regression analysis was used to examine predictors of treatment retention. Results indicated a two-variable model consisting of total number of co-occurring Axis I and II disorders, and pre-occupied attachment style, accounting for 17% of the variance. Attachment status predicted retention above and beyond psychiatric co-morbid disorders, demonstrating incremental predictive validity. Moderator analyses failed to detect an interaction. Among inpatients with substance abuse disorders, anxious-preoccupied attachment style predicted treatment retention, reflecting the importance of interpersonal components of treatment relationships in completing treatment. This study adds to a growing body of evidence linking attachment style with treatment adherence. Further research is needed to examine possible mechanisms associated with this relationship. Copyright © American Academy of Addiction Psychiatry.

Gender-specific risk factors for virologic failure in KwaZulu-Natal: Automobile ownership and financial insecurity

PubMed Central

HARE, Anna Q.; ORDÓÑEZ, Claudia E.; JOHNSON, Brent A.; RIO, Carlos DEL; KEARNS, Rachel A.; WU, Baohua; HAMPTON, Jane; WU, Peng; SUNPATH, Henry; MARCONI, Vincent C.

2014-01-01

We sought to examine which socioeconomic indicators are risk factors for virologic failure among HIV-1 infected patients receiving antiretroviral therapy in KwaZulu-Natal, South Africa. A case-control study of virologic failure was conducted among patients recruited from the outpatient clinic at McCord Hospital in Durban, South Africa between October 1, 2010 and June 30, 2012. Cases were those failing first-line antiretroviral therapy (ART), defined as viral load > 1000 copies/mL. Univariate logistic regression was performed on sociodemographic data for the outcome of virologic failure. Variables found significant (p<.05) were used in multivariate models and all models were stratified by gender. Of 158 cases and 300 controls, 35% were male and median age was 40 years. Gender stratification of models revealed automobile ownership was a risk factor among males, while variables of financial insecurity (unemployment, non-spouse family paying for care, staying with family) were risk factors for women. In this cohort, financial insecurity among women and automobile ownership among men were risk factors for virologic failure. Risk factor differences between genders demonstrate limitations of generalized risk factor analysis. PMID:25037488

Crop area estimation using high and medium resolution satellite imagery in areas with complex topography

NASA Astrophysics Data System (ADS)

Husak, G. J.; Marshall, M. T.; Michaelsen, J.; Pedreros, D.; Funk, C.; Galu, G.

2008-07-01

Reliable estimates of cropped area (CA) in developing countries with chronic food shortages are essential for emergency relief and the design of appropriate market-based food security programs. Satellite interpretation of CA is an effective alternative to extensive and costly field surveys, which fail to represent the spatial heterogeneity at the country-level. Bias-corrected, texture based classifications show little deviation from actual crop inventories, when estimates derived from aerial photographs or field measurements are used to remove systematic errors in medium resolution estimates. In this paper, we demonstrate a hybrid high-medium resolution technique for Central Ethiopia that combines spatially limited unbiased estimates from IKONOS images, with spatially extensive Landsat ETM+ interpretations, land-cover, and SRTM-based topography. Logistic regression is used to derive the probability of a location being crop. These individual points are then aggregated to produce regional estimates of CA. District-level analysis of Landsat based estimates showed CA totals which supported the estimates of the Bureau of Agriculture and Rural Development. Continued work will evaluate the technique in other parts of Africa, while segmentation algorithms will be evaluated, in order to automate classification of medium resolution imagery for routine CA estimation in the future.

Association of Nurse Engagement and Nurse Staffing on Patient Safety.

PubMed

Brooks Carthon, J Margo; Hatfield, Linda; Plover, Colin; Dierkes, Andrew; Davis, Lawrence; Hedgeland, Taylor; Sanders, Anne Marie; Visco, Frank; Holland, Sara; Ballinghoff, Jim; Del Guidice, Mary; Aiken, Linda H

2018-06-08

Nurse engagement is a modifiable element of the work environment and has shown promise as a potential safety intervention. Our study examined the relationship between the level of engagement, staffing, and assessments of patient safety among nurses working in hospital settings. A secondary analysis of linked cross-sectional data was conducted using survey data of 26 960 nurses across 599 hospitals in 4 states. Logistic regression models were used to examine the association between nurse engagement, staffing, and nurse assessments of patient safety. Thirty-two percent of nurses gave their hospital a poor or failing patient safety grade. In 25% of hospitals, nurses fell in the least or only somewhat engaged categories. A 1-unit increase in engagement lowered the odds of an unfavorable safety grade by 29% (P < .001). Hospitals where nurses reported higher levels of engagement were 19% (P < .001) less likely to report that mistakes were held against them. Nurses in poorly staffed hospitals were 6% more likely to report that important information about patients "fell through the cracks" when transferring patients across units (P < .001). Interventions to improve nurse engagement and adequate staffing serve as strategies to improve patient safety.

Gender-specific risk factors for virologic failure in KwaZulu-Natal: automobile ownership and financial insecurity.

PubMed

Hare, Anna Q; Ordóñez, Claudia E; Johnson, Brent A; Del Rio, Carlos; Kearns, Rachel A; Wu, Baohua; Hampton, Jane; Wu, Peng; Sunpath, Henry; Marconi, Vincent C

2014-11-01

We sought to examine which socioeconomic indicators are risk factors for virologic failure among HIV-1 infected patients receiving antiretroviral therapy (ART) in KwaZulu-Natal, South Africa. A case-control study of virologic failure was conducted among patients recruited from the outpatient clinic at McCord Hospital in Durban, South Africa between October 1, 2010 and June 30, 2012. Cases were those failing first-line ART, defined as viral load >1,000 copies/mL. Univariate logistic regression was performed on sociodemographic data for the outcome of virologic failure. Variables found significant (p < 0.05) were used in multivariate models and all models were stratified by gender. Of 158 cases and 300 controls, 35 % were male and median age was 40 years. Gender stratification of models revealed automobile ownership was a risk factor among males, while variables of financial insecurity (unemployment, non-spouse family paying for care, staying with family) were risk factors for women. In this cohort, financial insecurity among women and automobile ownership among men were risk factors for virologic failure. Risk factor differences between genders demonstrate limitations of generalized risk factor analysis.

An open trial of outpatient group therapy for bulimic disorders: combination program of cognitive behavioral therapy with assertive training and self-esteem enhancement.

PubMed

Shiina, Akihiro; Nakazato, Michiko; Mitsumori, Makoto; Koizumi, Hiroki; Shimizu, Eiji; Fujisaki, Mihisa; Iyo, Masaomi

2005-12-01

The purposes of this study were to examine the therapeutic efficacy of combined group cognitive behavioral therapy (CGCBT) and to explore the characteristics of the patients who failed to complete it. Our group cognitive behavioral therapy combined with assertiveness training for alexithymia and self-esteem enhancement therapy were attended over a 10-week period. Twenty-five participants were enrolled in the study. The clinical symptoms were assessed before and after treatment, using rating scales including the Eating Disorder Inventory-2, the Bulimic Investigatory Test, Edinburgh, the Toronto Alexithymia Scale, the Rosenberg Self-Esteem Scale, and Global Assessment of Functioning. Sixteen participants (64%) completed the CGCBT program. Completion of the CGCBT resulted in significant improvements in reducing binge-eating behavior and improving social functioning. Eight patients (32%) significantly improved using the Clinical Global Impression Change (CGI-C). Stepwise logistic regression analysis of the results indicated that a lower age (P=0.04) and psychiatric comorbidity (P=0.06) were predictors of dropout from the CGCBT program. Our CGCBT program is a promising first-line treatment for bulimic outpatients. Lower age and the presence of comorbidity had effects on dropout rates.

Smoking, death, and Alzheimer disease: a case of competing risks.

PubMed

Chang, Chung-Chou H; Zhao, Yongyun; Lee, Ching-Wen; Ganguli, Mary

2012-01-01

If smoking is a risk factor for Alzheimer disease (AD) but a smoker dies of another cause before developing or manifesting AD, smoking-related mortality may mask the relationship between smoking and AD. This phenomenon, referred to as competing risk, complicates efforts to model the effect of smoking on AD. Typical survival regression models assume that censorship from analysis is unrelated to an individual's probability for developing AD (ie, censoring is noninformative). However, if individuals who die before developing AD are younger than those who survive long enough to develop AD, and if they include a higher percentage of smokers than nonsmokers, the incidence of AD will appear to be higher in older individuals and in nonsmokers. Further, age-specific mortality rates are higher in smokers because they die earlier than nonsmokers. Therefore, if we fail to take into account the competing risk of death when we estimate the effect of smoking on AD, we bias the results and are in fact only comparing the incidence of AD in nonsmokers with that in the healthiest smokers. In this study, we demonstrate that the effect of smoking on AD differs in models that are and are not adjusted for competing risks.