Study of MRI in stratified viscous plasma configuration

NASA Astrophysics Data System (ADS)

Carlevaro, Nakia; Montani, Giovanni; Renzi, Fabrizio

2017-02-01

We analyze the morphology of the magneto-rotational instability (MRI) for a stratified viscous plasma disk configuration in differential rotation, taking into account the so-called corotation theorem for the background profile. In order to select the intrinsic Alfvénic nature of MRI, we deal with an incompressible plasma and we adopt a formulation of the local perturbation analysis based on the use of the magnetic flux function as a dynamical variable. Our study outlines, as consequence of the corotation condition, a marked asymmetry of the MRI with respect to the equatorial plane, particularly evident in a complete damping of the instability over a positive critical height on the equatorial plane. We also emphasize how such a feature is already present (although less pronounced) even in the ideal case, restoring a dependence of the MRI on the stratified morphology of the gravitational field.

Undersized description on motile gyrotactic micro-organisms individualities in MHD stratified water-based Newtonian nanofluid

NASA Astrophysics Data System (ADS)

Rehman, Khalil Ur; Malik, Aneeqa Ashfaq; Tahir, M.; Malik, M. Y.

2018-03-01

The current pagination summarized the influence of bio-convection Schmidt number, bio-convection Peclet number and micro-organisms concentration difference parameter on the density of motile gyrotactic micro-organisms when they have interaction with the thermally stratified magneto-nanofluid flow past a vertical stretching surface. It is observed that the density of motile microorganisms is the decreasing function of the bio-convection Schmidt and Peclet numbers. It is trusted that the outcomes of present analysis will serve as a helping source for the upcoming developments regarding individualities of motile gyrotactic micro-organisms subject to boundary layer flows induced by stretching surfaces.

Exploring the cost-utility of stratified primary care management for low back pain compared with current best practice within risk-defined subgroups.

PubMed

Whitehurst, David G T; Bryan, Stirling; Lewis, Martyn; Hill, Jonathan; Hay, Elaine M

2012-11-01

Stratified management for low back pain according to patients' prognosis and matched care pathways has been shown to be an effective treatment approach in primary care. The aim of this within-trial study was to determine the economic implications of providing such an intervention, compared with non-stratified current best practice, within specific risk-defined subgroups (low-risk, medium-risk and high-risk). Within a cost-utility framework, the base-case analysis estimated the incremental healthcare cost per additional quality-adjusted life year (QALY), using the EQ-5D to generate QALYs, for each risk-defined subgroup. Uncertainty was explored with cost-utility planes and acceptability curves. Sensitivity analyses were performed to consider alternative costing methodologies, including the assessment of societal loss relating to work absence and the incorporation of generic (ie, non-back pain) healthcare utilisation. The stratified management approach was a cost-effective treatment strategy compared with current best practice within each risk-defined subgroup, exhibiting dominance (greater benefit and lower costs) for medium-risk patients and acceptable incremental cost to utility ratios for low-risk and high-risk patients. The likelihood that stratified care provides a cost-effective use of resources exceeds 90% at willingness-to-pay thresholds of £4000 (≈ 4500; $6500) per additional QALY for the medium-risk and high-risk groups. Patients receiving stratified care also reported fewer back pain-related days off work in all three subgroups. Compared with current best practice, stratified primary care management for low back pain provides a highly cost-effective use of resources across all risk-defined subgroups.

Aligning population-based care management with chronic disease complexity.

PubMed

Hewner, Sharon; Seo, Jin Young; Gothard, Sandra E; Johnson, Barbara J

2014-01-01

Risk-stratified care management requires knowledge of the complexity of chronic disease and comorbidity, information that is often not readily available in the primary care setting. The purpose of this article was to describe a population-based approach to risk-stratified care management that could be applied in primary care. Three populations (Medicaid, Medicare, and privately insured) at a regional health plan were divided into risk-stratified cohorts based on chronic disease and complexity, and utilization was compared before and after the implementation of population-specific care management teams of nurses. Risk-stratified care management was associated with reductions in hospitalization rates in all three populations, but the opportunities to avoid admissions were different. Knowledge of population complexity is critical to the development of risk-stratified care management in primary care, and a complexity matrix can help nurses identify gaps in care and align interventions to cohort and population needs. Copyright © 2014 Elsevier Inc. All rights reserved.

Physical Activity among Rural Older Adults with Diabetes

ERIC Educational Resources Information Center

Arcury, Thomas A.; Snively, Beverly M.; Bell, Ronny A.; Smith, Shannon L.; Stafford, Jeanette M.; Wetmore-Arkader, Lindsay K.; Quandt, Sara A.

2006-01-01

Purpose: This analysis describes physical activity levels and factors associated with physical activity in an ethnically diverse (African American, Native American, white) sample of rural older adults with diabetes. Method: Data were collected using a population-based, cross-sectional stratified random sample survey of 701 community-dwelling…

Genome-wide meta-analyses of stratified depression in Generation Scotland and UK Biobank.

PubMed

Hall, Lynsey S; Adams, Mark J; Arnau-Soler, Aleix; Clarke, Toni-Kim; Howard, David M; Zeng, Yanni; Davies, Gail; Hagenaars, Saskia P; Maria Fernandez-Pujals, Ana; Gibson, Jude; Wigmore, Eleanor M; Boutin, Thibaud S; Hayward, Caroline; Scotland, Generation; Porteous, David J; Deary, Ian J; Thomson, Pippa A; Haley, Chris S; McIntosh, Andrew M

2018-01-10

Few replicable genetic associations for Major Depressive Disorder (MDD) have been identified. Recent studies of MDD have identified common risk variants by using a broader phenotype definition in very large samples, or by reducing phenotypic and ancestral heterogeneity. We sought to ascertain whether it is more informative to maximize the sample size using data from all available cases and controls, or to use a sex or recurrent stratified subset of affected individuals. To test this, we compared heritability estimates, genetic correlation with other traits, variance explained by MDD polygenic score, and variants identified by genome-wide meta-analysis for broad and narrow MDD classifications in two large British cohorts - Generation Scotland and UK Biobank. Genome-wide meta-analysis of MDD in males yielded one genome-wide significant locus on 3p22.3, with three genes in this region (CRTAP, GLB1, and TMPPE) demonstrating a significant association in gene-based tests. Meta-analyzed MDD, recurrent MDD and female MDD yielded equivalent heritability estimates, showed no detectable difference in association with polygenic scores, and were each genetically correlated with six health-correlated traits (neuroticism, depressive symptoms, subjective well-being, MDD, a cross-disorder phenotype and Bipolar Disorder). Whilst stratified GWAS analysis revealed a genome-wide significant locus for male MDD, the lack of independent replication, and the consistent pattern of results in other MDD classifications suggests that phenotypic stratification using recurrence or sex in currently available sample sizes is currently weakly justified. Based upon existing studies and our findings, the strategy of maximizing sample sizes is likely to provide the greater gain.

Stratified rotating Boussinesq equations in geophysical fluid dynamics: Dynamic bifurcation and periodic solutions

NASA Astrophysics Data System (ADS)

Hsia, Chun-Hsiung; Ma, Tian; Wang, Shouhong

2007-06-01

The main objective of this article is to study the dynamics of the stratified rotating Boussinesq equations, which are a basic model in geophysical fluid dynamics. First, for the case where the Prandtl number is greater than 1, a complete stability and bifurcation analysis near the first critical Rayleigh number is carried out. Second, for the case where the Prandtl number is smaller than 1, the onset of the Hopf bifurcation near the first critical Rayleigh number is established, leading to the existence of nontrivial periodic solutions. The analysis is based on a newly developed bifurcation and stability theory for nonlinear dynamical systems (both finite and infinite dimensional) by two of the authors [T. Ma and S. Wang, Bifurcation Theory and Applications, World Scientific Series on Nonlinear Sciences Vol. 53 (World Scientific, Singapore, 2005)].

Survival analysis of cervical cancer using stratified Cox regression

NASA Astrophysics Data System (ADS)

Purnami, S. W.; Inayati, K. D.; Sari, N. W. Wulan; Chosuvivatwong, V.; Sriplung, H.

2016-04-01

Cervical cancer is one of the mostly widely cancer cause of the women death in the world including Indonesia. Most cervical cancer patients come to the hospital already in an advanced stadium. As a result, the treatment of cervical cancer becomes more difficult and even can increase the death's risk. One of parameter that can be used to assess successfully of treatment is the probability of survival. This study raises the issue of cervical cancer survival patients at Dr. Soetomo Hospital using stratified Cox regression based on six factors such as age, stadium, treatment initiation, companion disease, complication, and anemia. Stratified Cox model is used because there is one independent variable that does not satisfy the proportional hazards assumption that is stadium. The results of the stratified Cox model show that the complication variable is significant factor which influent survival probability of cervical cancer patient. The obtained hazard ratio is 7.35. It means that cervical cancer patient who has complication is at risk of dying 7.35 times greater than patient who did not has complication. While the adjusted survival curves showed that stadium IV had the lowest probability of survival.

Ancestry-based stratified analysis of Immunochip data identifies novel associations with celiac disease.

PubMed

Garcia-Etxebarria, Koldo; Jauregi-Miguel, Amaia; Romero-Garmendia, Irati; Plaza-Izurieta, Leticia; Legarda, Maria; Irastorza, Iñaki; Bilbao, Jose Ramon

2016-12-01

To identify candidate genes in celiac disease (CD), we reanalyzed the whole Immunochip CD cohort using a different approach that clusters individuals based on immunoancestry prior to disease association analysis, rather than by geographical origin. We detected 636 new associated SNPs (P<7.02 × 10 -07 ) and identified 5 novel genomic regions, extended 8 others previously identified and also detected 18 isolated signals defined by one or very few significant SNPs. To test whether we could identify putative candidate genes, we performed expression analyses of several genes from the top novel region (chr2:134533564-136169524), from a previously identified locus that is now extended, and a gene marked by an isolated SNP, in duodenum biopsies of active and treated CD patients, and non-celiac controls. In the largest novel region, CCNT2 and R3HDM1 were constitutively underexpressed in disease, even after gluten removal. Moreover, several genes within this region were coexpressed in patients, but not in controls. Other novel genes like KIF21B, REL and SORD also showed altered expression in active disease. Apart from the identification of novel CD loci, these results suggest that ancestry-based stratified analysis is an efficient strategy for association studies in complex diseases.

Development of WAIS-III General Ability Index Minus WMS-III memory discrepancy scores.

PubMed

Lange, Rael T; Chelune, Gordon J; Tulsky, David S

2006-09-01

Analysis of the discrepancy between intellectual functioning and memory ability has received some support as a useful means for evaluating memory impairment. In recent additions to Wechlser scale interpretation, the WAIS-III General Ability Index (GAI) and the WMS-III Delayed Memory Index (DMI) were developed. The purpose of this investigation is to develop base rate data for GAI-IMI, GAI-GMI, and GAI-DMI discrepancy scores using data from the WAIS-III/WMS-III standardization sample (weighted N = 1250). Base rate tables were developed using the predicted-difference method and two simple-difference methods (i.e., stratified and non-stratified). These tables provide valuable data for clinical reference purposes to determine the frequency of GAI-IMI, GAI-GMI, and GAI-DMI discrepancy scores in the WAIS-III/WMS-III standardization sample.

Analysis of Turbulent Combustion in Simplified Stratified Charge Conditions

NASA Astrophysics Data System (ADS)

Moriyoshi, Yasuo; Morikawa, Hideaki; Komatsu, Eiji

The stratified charge combustion system has been widely studied due to the significant potentials for low fuel consumption rate and low exhaust gas emissions. The fuel-air mixture formation process in a direct-injection stratified charge engine is influenced by various parameters, such as atomization, evaporation, and in-cylinder gas motion at high temperature and high pressure conditions. It is difficult to observe the in-cylinder phenomena in such conditions and also challenging to analyze the following stratified charge combustion. Therefore, the combustion phenomena in simplified stratified charge conditions aiming to analyze the fundamental stratified charge combustion are examined. That is, an experimental apparatus which can control the mixture distribution and the gas motion at ignition timing was developed, and the effects of turbulence intensity, mixture concentration distribution, and mixture composition on stratified charge combustion were examined. As a result, the effects of fuel, charge stratification, and turbulence on combustion characteristics were clarified.

Use of simulation to compare the performance of minimization with stratified blocked randomization.

PubMed

Toorawa, Robert; Adena, Michael; Donovan, Mark; Jones, Steve; Conlon, John

2009-01-01

Minimization is an alternative method to stratified permuted block randomization, which may be more effective at balancing treatments when there are many strata. However, its use in the regulatory setting for industry trials remains controversial, primarily due to the difficulty in interpreting conventional asymptotic statistical tests under restricted methods of treatment allocation. We argue that the use of minimization should be critically evaluated when designing the study for which it is proposed. We demonstrate by example how simulation can be used to investigate whether minimization improves treatment balance compared with stratified randomization, and how much randomness can be incorporated into the minimization before any balance advantage is no longer retained. We also illustrate by example how the performance of the traditional model-based analysis can be assessed, by comparing the nominal test size with the observed test size over a large number of simulations. We recommend that the assignment probability for the minimization be selected using such simulations. Copyright (c) 2008 John Wiley & Sons, Ltd.

Stratifying to reduce bias caused by high nonresponse rates: A case study from New Mexico’s forest inventory

Treesearch

Sara A. Goeking; Paul L. Patterson

2013-01-01

The USDA Forest Service’s Forest Inventory and Analysis (FIA) Program applies specific sampling and analysis procedures to estimate a variety of forest attributes. FIA’s Interior West region uses post-stratification, where strata consist of forest/nonforest polygons based on MODIS imagery, and assumes that nonresponse plots are distributed at random across each stratum...

A Matter of Classes: Stratifying Health Care Populations to Produce Better Estimates of Inpatient Costs

PubMed Central

Rein, David B

2005-01-01

Objective To stratify traditional risk-adjustment models by health severity classes in a way that is empirically based, is accessible to policy makers, and improves predictions of inpatient costs. Data Sources Secondary data created from the administrative claims from all 829,356 children aged 21 years and under enrolled in Georgia Medicaid in 1999. Study Design A finite mixture model was used to assign child Medicaid patients to health severity classes. These class assignments were then used to stratify both portions of a traditional two-part risk-adjustment model predicting inpatient Medicaid expenditures. Traditional model results were compared with the stratified model using actuarial statistics. Principal Findings The finite mixture model identified four classes of children: a majority healthy class and three illness classes with increasing levels of severity. Stratifying the traditional two-part risk-adjustment model by health severity classes improved its R2 from 0.17 to 0.25. The majority of additional predictive power resulted from stratifying the second part of the two-part model. Further, the preference for the stratified model was unaffected by months of patient enrollment time. Conclusions Stratifying health care populations based on measures of health severity is a powerful method to achieve more accurate cost predictions. Insurers who ignore the predictive advances of sample stratification in setting risk-adjusted premiums may create strong financial incentives for adverse selection. Finite mixture models provide an empirically based, replicable methodology for stratification that should be accessible to most health care financial managers. PMID:16033501

Depression-related differences in lean body mass distribution from National Health and Nutrition Examination Survey 2005-2006.

PubMed

Li, Ying; Meng, Lu; Li, Yue; Sato, Yasuto

2014-03-01

Although the association between depression and body composition has been widely discussed, the effects of depression on lean body mass (LBM) are unclear. The present study aimed to investigate the association of depression with LBM. The study included 2406 participants aged 18-69 years. The sex and body mass index (BMI) stratified analysis of covariance was performed to compare total LBM and percentage LBM (%LBM) in subjects with different depression score levels. Multiple linear regression analysis was conducted to estimate the association between depression score and serum albumin level. An analysis of covariance stratified by sex showed that participants with moderate-to-severe depression had significantly decreased total LBM and total and regional %LBM in men, except for total LBM and percentage gynoid LBM, which was observed in women. In the BMI stratified analysis of covariance, depression was significantly associated with decreased total and regional %LBM and with increased total and regional percentage fat body mass. In people with BMI≥25kg/m(2), the associations between depression or depressive syndrome and LBM, and total and regional %LBM are stronger compared to those with BMI<25kg/m(2). Multiple linear regression analysis showed that depression score was significantly negatively associated with serum albumin level. This is a cross-sectional study based on a general population, some information about clinical diagnosis and medication use is not available. Depression had a significant negative association with LBM and serum albumin level. Copyright © 2014 Elsevier B.V. All rights reserved.

The first report of Japanese antimicrobial use measured by national database based on health insurance claims data (2011-2013): comparison with sales data, and trend analysis stratified by antimicrobial category and age group.

PubMed

Yamasaki, Daisuke; Tanabe, Masaki; Muraki, Yuichi; Kato, Genta; Ohmagari, Norio; Yagi, Tetsuya

2018-04-01

Our objective was to evaluate the utility of the national database (NDB) based on health insurance claims data for antimicrobial use (AMU) surveillance in medical institutions in Japan. The population-weighted total AMU expressed as defined daily doses (DDDs) per 1000 inhabitants per day (DID) was measured by the NDB. The data were compared with our previous study measured by the sales data. Trend analysis of DID from 2011 to 2013 and subgroup analysis stratified by antimicrobial category and age group were performed. There was a significant linear correlation between the AMUs measured by the sales data and the NDB. Total oral and parenteral AMUs (expressed in DID) were 1.04-fold from 12.654 in 2011 to 13.202 in 2013 and 1.13-fold from 0.734 to 0.829, respectively. Percentage of oral form among total AMU was high with more than 94% during the study period. AMU in the children group (0-14 years) decreased from 2011 to 2013 regardless of dosage form, although the working age group (15-64 years) and elderly group (65 and above years) increased. Oral AMU in the working age group was approximately two-thirds of those in the other age groups. In contrast, parenteral AMU in the elderly group was extremely high compared to the other age groups. The trend of AMU stratified by antimicrobial category and age group were successfully measured using the NDB, which can be a tool to monitor outcome indices for the national action plan on antimicrobial resistance.

Effect of stratified care for low back pain in family practice (IMPaCT Back): a prospective population-based sequential comparison.

PubMed

Foster, Nadine E; Mullis, Ricky; Hill, Jonathan C; Lewis, Martyn; Whitehurst, David G T; Doyle, Carol; Konstantinou, Kika; Main, Chris; Somerville, Simon; Sowden, Gail; Wathall, Simon; Young, Julie; Hay, Elaine M

2014-01-01

We aimed to determine the effects of implementing risk-stratified care for low back pain in family practice on physician's clinical behavior, patient outcomes, and costs. The IMPaCT Back Study (IMplementation to improve Patient Care through Targeted treatment) prospectively compared separate patient cohorts in a preintervention phase (6 months of usual care) and a postintervention phase (12 months of stratified care) in family practice, involving 64 family physicians and linked physical therapy services. A total of 1,647 adults with low back pain were invited to participate. Stratified care entailed use of a risk stratification tool to classify patients into groups at low, medium, or high risk for persistent disability and provision of risk-matched treatment. The primary outcome was 6-month change in disability as assessed with the Roland-Morris Disability Questionnaire. Process outcomes captured physician behavior change in risk-appropriate referral to physical therapy, diagnostic tests, medication prescriptions, and sickness certifications. A cost-utility analysis estimated incremental quality-adjusted life-years and back-related health care costs. Analysis was by intention to treat. The 922 patients studied (368 in the preintervention phase and 554 in the postintervention phase) had comparable baseline characteristics. At 6 months follow-up, stratified care had a small but significant benefit relative to usual care as seen from a mean difference in Roland-Morris Disability Questionnaire scores of 0.7 (95% CI, 0.1-1.4), with a large, clinically important difference in the high risk group of 2.3 (95% CI, 0.8-3.9). Mean time off work was 50% shorter (4 vs 8 days, P = .03) and the proportion of patients given sickness certifications was 30% lower (9% vs 15%, P = .03) in the postintervention cohort. Health care cost savings were also observed. Stratified care for back pain implemented in family practice leads to significant improvements in patient disability outcomes and a halving in time off work, without increasing health care costs. Wider implementation is recommended.

A Description of the Building Materials Data Base for Portland, Maine.

DTIC Science & Technology

1986-06-01

WORDS (Continue on reveree side if neceseary and Identify by block number)". Acid precipitation, , Data bases, Damage assessment, Environmental...protection) Damage from acid deposition, Portland, Maine Damage to buildings, - Statistical analysis, . 20. ASsrRACT (Conlaue a reverse e(A It n -cwery md...types and amounts of building surface materials ex- posed to acid deposition. The stratified, systematic, unaligned random sampling approach was used

Effects of equivalence ratio variation on lean, stratified methane-air laminar counterflow flames

NASA Astrophysics Data System (ADS)

Richardson, E. S.; Granet, V. E.; Eyssartier, A.; Chen, J. H.

2010-11-01

The effects of equivalence ratio variations on flame structure and propagation have been studied computationally. Equivalence ratio stratification is a key technology for advanced low emission combustors. Laminar counterflow simulations of lean methane-air combustion have been presented which show the effect of strain variations on flames stabilized in an equivalence ratio gradient, and the response of flames propagating into a mixture with a time-varying equivalence ratio. 'Back supported' lean flames, whose products are closer to stoichiometry than their reactants, display increased propagation velocities and reduced thickness compared with flames where the reactants are richer than the products. The radical concentrations in the vicinity of the flame are modified by the effect of an equivalence ratio gradient on the temperature profile and thermal dissociation. Analysis of steady flames stabilized in an equivalence ratio gradient demonstrates that the radical flux through the flame, and the modified radical concentrations in the reaction zone, contribute to the modified propagation speed and thickness of stratified flames. The modified concentrations of radical species in stratified flames mean that, in general, the reaction rate is not accurately parametrized by progress variable and equivalence ratio alone. A definition of stratified flame propagation based upon the displacement speed of a mixture fraction dependent progress variable was seen to be suitable for stratified combustion. The response times of the reaction, diffusion, and cross-dissipation components which contribute to this displacement speed have been used to explain flame response to stratification and unsteady fluid dynamic strain.

The effectiveness of a community-based breast cancer education intervention in the New York State Capital Region.

PubMed

Zeinomar, Nur; Moslehi, Roxana

2013-09-01

We determined the effectiveness of a community-based breast cancer education intervention among understudied populations in the New York State (NYS) Capital Region by assessing and comparing baseline and post-education breast cancer knowledge. Participants included 417 students recruited from five colleges/universities and 67 women from four community group organizations. Baseline and post-education knowledge was assessed via self-administered mostly multiple-choice questionnaires. An open-ended question soliciting opinions about public health prevention strategies against breast cancer was included on college/university students' questionnaires. Effectiveness of education intervention was estimated through a paired t test. Stratified analysis was done using demographic and descriptive variables. Answers to the open-ended questions were analyzed qualitatively. The mean percentage of correct answers increased from 39.9% at baseline to 80.8% post-education (P < 0.0001) among college/university students and from 43.5% to 77.8% (P < 0.0001) among community group members. Effectiveness remained statistically significant in all stratified analyses with similarly high percentage of correct answers achieved post-education irrespective of knowledge level at baseline. Stratified analysis also revealed similar patterns of improvement in overall knowledge and narrowing of the gap in post-education knowledge. Primary prevention emerged as the dominant theme post-education in students' responses to the open-ended question, signifying the effectiveness of our education in raising awareness about modifiable risk factors and inspiring proactive thinking about public health prevention strategies. This community-based education intervention was effective in increasing breast cancer knowledge among demographically diverse groups with low levels of baseline knowledge in the NYS Capital Region. Our findings provide leads for future public health prevention strategies.

Evidence base and future research directions in the management of low back pain.

PubMed

Abbott, Allan

2016-03-18

Low back pain (LBP) is a prevalent and costly condition. Awareness of valid and reliable patient history taking, physical examination and clinical testing is important for diagnostic accuracy. Stratified care which targets treatment to patient subgroups based on key characteristics is reliant upon accurate diagnostics. Models of stratified care that can potentially improve treatment effects include prognostic risk profiling for persistent LBP, likely response to specific treatment based on clinical prediction models or suspected underlying causal mechanisms. The focus of this editorial is to highlight current research status and future directions for LBP diagnostics and stratified care.

Optimal Stratification of Item Pools in a-Stratified Computerized Adaptive Testing.

ERIC Educational Resources Information Center

Chang, Hua-Hua; van der Linden, Wim J.

2003-01-01

Developed a method based on 0-1 linear programming to stratify an item pool optimally for use in alpha-stratified adaptive testing. Applied the method to a previous item pool from the computerized adaptive test of the Graduate Record Examinations. Results show the new method performs well in practical situations. (SLD)

Spatial Analysis of Geothermal Resource Potential in New York and Pennsylvania: A Stratified Kriging Approach

NASA Astrophysics Data System (ADS)

Smith, J. D.; Whealton, C. A.; Stedinger, J. R.

2014-12-01

Resource assessments for low-grade geothermal applications employ available well temperature measurements to determine if the resource potential is sufficient for supporting district heating opportunities. This study used a compilation of bottomhole temperature (BHT) data from recent unconventional shale oil and gas wells, along with legacy oil, gas, and storage wells, in Pennsylvania (PA) and New York (NY). Our study's goal was to predict the geothermal resource potential and associated uncertainty for the NY-PA region using kriging interpolation. The dataset was scanned for outliers, and some observations were removed. Because these wells were drilled for reasons other than geothermal resource assessment, their spatial density varied widely. An exploratory spatial statistical analysis revealed differences in the spatial structure of the geothermal gradient data (the kriging semi-variogram and its nugget variance, shape, sill, and the degree of anisotropy). As a result, a stratified kriging procedure was adopted to better capture the statistical structure of the data, to generate an interpolated surface, and to quantify the uncertainty of the computed surface. The area was stratified reflecting different physiographic provinces in NY and PA that have geologic properties likely related to variations in the value of the geothermal gradient. The kriging prediction and the variance-of-prediction were determined for each province by the generation of a semi-variogram using only the wells that were located within that province. A leave-one-out cross validation (LOOCV) was conducted as a diagnostic tool. The results of stratified kriging were compared to kriging using the whole region to determine the impact of stratification. The two approaches provided similar predictions of the geothermal gradient. However, the variance-of-prediction was different. The stratified approach is recommended because it gave a more appropriate site-specific characterization of uncertainty based upon a more realistic description of the statistical structure of the data given the geologic characteristics of each province.

Limitations of studies on school-based nutrition education interventions for obesity in China: a systematic review and meta-analysis.

PubMed

Kong, Kaimeng; Liu, Jie; Tao, Yexuan

2016-01-01

School-based nutrition education has been widely implemented in recent years to fight the increasing prevalence of childhood obesity in China. A comprehensive literature search was performed using six databases to identify studies of school-based nutrition education interventions in China. The methodological quality and the risk of bias of selected literature were evaluated. Stratified analysis was performed to identify whether different methodologies influenced the estimated effect of the intervention. Seventeen articles were included in the analysis. Several of the included studies had inadequate intervention duration, inappropriate randomization methods, selection bias, unbalanced baseline characteristics between control and intervention groups, and absent sample size calculation. Overall, the studies showed no significant impact of nutrition education on obesity (OR=0.76; 95% CI=0.55-1.05; p=0.09). This can be compared with an OR of 0.68 for interventions aimed at preventing malnutrition and an OR of 0.49 for interventions aimed at preventing iron-deficiency anemia. When studies with unbalanced baseline characteristics between groups and selection bias in the study subjects were excluded, the impact of nutrition education on obesity was significant (OR=0.73; 95% CI=0.55-0.98; p=0.003). An analysis stratified according to the duration of intervention revealed that the intervention was effective only when it lasted for more than 2 years (OR=0.49, 95% CI=0.42-0.58; p<0.001). Studies of school-based nutrition education programs in China have some important limitations that might affect the estimated effectiveness of the intervention.

The linear trend of headache prevalence and some headache features in school children.

PubMed

Ozge, Aynur; Buğdayci, Resul; Saşmaz, Tayyar; Kaleağasi, Hakan; Kurt, Oner; Karakelle, Ali; Siva, Aksel

2007-04-01

The objectives of this study were to determine the age and sex dependent linear trend of recurrent headache prevalence in schoolchildren in Mersin. A stratified sample composed of 5562 children; detailed characteristics were previously published. In this study the prevalence distribution of headache by age and sex showed a peak in the female population at the age of 11 (27.2%) with a plateau in the following years. The great stratified random sample results suggested that, in addition to socio-demographic features, detailed linear trend analysis showed headache features of children with headache have some specific characteristics dependent on age, gender and headache type. This study results can constitute a basis for the future epidemiological based studies.

Stratified spin-up in a sliced, square cylinder

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

Munro, R. J.; Foster, M. R.

We previously reported experimental and theoretical results on the linear spin-up of a linearly stratified, rotating fluid in a uniform-depth square cylinder [M. R. Foster and R. J. Munro, “The linear spin-up of a stratified, rotating fluid in a square cylinder,” J. Fluid Mech. 712, 7–40 (2012)]. Here we extend that analysis to a “sliced” square cylinder, which has a base-plane inclined at a shallow angle α. Asymptotic results are derived that show the spin-up phase is achieved by a combination of the Ekman-layer eruptions (from the perimeter region of the cylinder's lid and base) and cross-slope-propagating stratified Rossby waves.more » The final, steady state limit for this spin-up phase is identical to that found previously for the uniform depth cylinder, but is reached somewhat more rapidly on a time scale of order E{sup −1/2}Ω{sup −1}/log (α/E{sup 1/2}) (compared to E{sup −1/2}Ω{sup −1} for the uniform-depth cylinder), where Ω is the rotation rate and E the Ekman number. Experiments were performed for Burger numbers, S, between 0.4 and 16, and showed that for S≳O(1), the Rossby modes are severely damped, and it is only at small S, and during the early stages, that the presence of these wave modes was evident. These observations are supported by the theory, which shows the damping factors increase with S and are numerically large for S≳O(1)« less

Ultrasound-Based Risk Stratification for Malignancy in Thyroid Nodules: A Four-Tier Categorization System.

PubMed

Seo, Hyobin; Na, Dong Gyu; Kim, Ji-Hoon; Kim, Kyung Won; Yoon, Ji Won

2015-07-01

The purpose of this study was to stratify the malignancy risk of US features, with an emphasis on nodule echogenicity. A total of 1,058 nodules of 824 consecutive patients (236 malignant and 822 benign) were included in this study. Malignancy risk of each nodule was analyzed according to US features, with an emphasis on nodule echogenecity, and was stratified into 4-tier categories. In multivariate analysis, isoechogenicity, indistinct margin, non-solid internal content, and parallel orientation were predictive of benign nodules (P < 0.002), while hypoechogenicity, marked hypoechogenicity, spiculated/microlobulated margin, solid content, nonparallel orientation (taller than wide), microcalcification, and macrocalcification were predictive of malignancy (P ≤ 0.037). Although the presence of US features associated with malignancy was significantly predictive of malignancy in hypoechoic and markedly hypoechoic nodules (P ≤ 0.004), it was not associated with malignancy in isoechoic or hyperechoic nodules. Thyroid nodules could be stratified into four categories according to the malignancy risk: benign (risk 0%), probably benign (risk ≤ 5%), indeterminate (risk > 5 and < 50%), and suspicion of malignancy (risk > 50%). The US-based four-tier categorization system will be useful for predicting the risk of malignancy and decisions regarding FNA for thyroid nodules. • No US feature was predictive of malignancy in isoechoic nodules. • Isoechoic nodules without calcification can be included in the probably benign category. • We suggest a four-tier categorization stratified primarily by nodule echogenecity. • The four-tier categorization of thyroid nodules will be useful for FNA decisions.

Identifying prognostic intratumor heterogeneity using pre- and post-radiotherapy 18F-FDG PET images for pancreatic cancer patients.

PubMed

Yue, Yong; Osipov, Arsen; Fraass, Benedick; Sandler, Howard; Zhang, Xiao; Nissen, Nicholas; Hendifar, Andrew; Tuli, Richard

2017-02-01

To stratify risks of pancreatic adenocarcinoma (PA) patients using pre- and post-radiotherapy (RT) PET/CT images, and to assess the prognostic value of texture variations in predicting therapy response of patients. Twenty-six PA patients treated with RT from 2011-2013 with pre- and post-treatment 18F-FDG-PET/CT scans were identified. Tumor locoregional texture was calculated using 3D kernel-based approach, and texture variations were identified by fitting discrepancies of texture maps of pre- and post-treatment images. A total of 48 texture and clinical variables were identified and evaluated for association with overall survival (OS). The prognostic heterogeneity features were selected using lasso/elastic net regression, and further were evaluated by multivariate Cox analysis. Median age was 69 y (range, 46-86 y). The texture map and temporal variations between pre- and post-treatment were well characterized by histograms and statistical fitting. The lasso analysis identified seven predictors (age, node stage, post-RT SUVmax, variations of homogeneity, variance, sum mean, and cluster tendency). The multivariate Cox analysis identified five significant variables: age, node stage, variations of homogeneity, variance, and cluster tendency (with P=0.020, 0.040, 0.065, 0.078, and 0.081, respectively). The patients were stratified into two groups based on the risk score of multivariate analysis with log-rank P=0.001: a low risk group (n=11) with a longer mean OS (29.3 months) and higher texture variation (>30%), and a high risk group (n=15) with a shorter mean OS (17.7 months) and lower texture variation (<15%). Locoregional metabolic texture response provides a feasible approach for evaluating and predicting clinical outcomes following treatment of PA with RT. The proposed method can be used to stratify patient risk and help select appropriate treatment strategies for individual patients toward implementing response-driven adaptive RT.

Evidence base and future research directions in the management of low back pain

PubMed Central

Abbott, Allan

2016-01-01

Low back pain (LBP) is a prevalent and costly condition. Awareness of valid and reliable patient history taking, physical examination and clinical testing is important for diagnostic accuracy. Stratified care which targets treatment to patient subgroups based on key characteristics is reliant upon accurate diagnostics. Models of stratified care that can potentially improve treatment effects include prognostic risk profiling for persistent LBP, likely response to specific treatment based on clinical prediction models or suspected underlying causal mechanisms. The focus of this editorial is to highlight current research status and future directions for LBP diagnostics and stratified care. PMID:27004162

Assessment of the prognostic and predictive utility of the Breast Cancer Index (BCI): an NCIC CTG MA.14 study.

PubMed

Sgroi, Dennis C; Chapman, Judy-Anne W; Badovinac-Crnjevic, T; Zarella, Elizabeth; Binns, Shemeica; Zhang, Yi; Schnabel, Catherine A; Erlander, Mark G; Pritchard, Kathleen I; Han, Lei; Shepherd, Lois E; Goss, Paul E; Pollak, Michael

2016-01-04

Biomarkers that can be used to accurately assess the residual risk of disease recurrence in women with hormone receptor-positive breast cancer are clinically valuable. We evaluated the prognostic value of the Breast Cancer Index (BCI), a continuous risk index based on a combination of HOXB13:IL17BR and molecular grade index, in women with early breast cancer treated with either tamoxifen alone or tamoxifen plus octreotide in the NCIC MA.14 phase III clinical trial (ClinicalTrials.gov Identifier NCT00002864; registered 1 November 1999). Gene expression analysis of BCI by real-time polymerase chain reaction was performed blinded to outcome on RNA extracted from archived formalin-fixed, paraffin-embedded tumor samples of 299 patients with both lymph node-negative (LN-) and lymph node-positive (LN+) disease enrolled in the MA.14 trial. Our primary objective was to determine the prognostic performance of BCI based on relapse-free survival (RFS). MA.14 patients experienced similar RFS on both treatment arms. Association of gene expression data with RFS was evaluated in univariate analysis with a stratified log-rank test statistic, depicted with a Kaplan-Meier plot and an adjusted Cox survivor plot. In the multivariate assessment, we used stratified Cox regression. The prognostic performance of an emerging, optimized linear BCI model was also assessed in a post hoc analysis. Of 299 samples, 292 were assessed successfully for BCI for 146 patients accrued in each MA.14 treatment arm. BCI risk groups had a significant univariate association with RFS (stratified log-rank p = 0.005, unstratified log-rank p = 0.007). Adjusted 10-year RFS in BCI low-, intermediate-, and high-risk groups was 87.5 %, 83.9 %, and 74.7 %, respectively. BCI had a significant prognostic effect [hazard ratio (HR) 2.34, 95 % confidence interval (CI) 1.33-4.11; p = 0.004], although not a predictive effect, on RFS in stratified multivariate analysis, adjusted for pathological tumor stage (HR 2.22, 95 % CI 1.22-4.07; p = 0.01). In the post hoc multivariate analysis, higher linear BCI was associated with shorter RFS (p = 0.002). BCI had a strong prognostic effect on RFS in patients with early-stage breast cancer treated with tamoxifen alone or with tamoxifen and octreotide. BCI was prognostic in both LN- and LN+ patients. This retrospective study is an independent validation of the prognostic performance of BCI in a prospective trial.

Extricating Sex and Gender in Air Pollution Research: A Community-Based Study on Cardinal Symptoms of Exposure

PubMed Central

Oiamo, Tor H.; Luginaah, Isaac N.

2013-01-01

This study investigated sex and gender differences in cardinal symptoms of exposure to a mixture of ambient pollutants. A cross sectional population-based study design was utilized in Sarnia, ON, Canada. Stratified random sampling in census tracts of residents aged 18 and over recruited 804 respondents. Respondents completed a community health survey of chronic disease, general health, and socioeconomic indicators. Residential concentrations of NO2, SO2, benzene, toluene, ethylbenzene and o/m/p-xylene were estimated by land use regression on data collected through environmental monitoring. Classification and Regression Tree (CART) analysis was used to identify variables that interacted with sex and cardinal symptoms of exposure, and a series of logistic regression models were built to predict the reporting of five or more cardinal symptoms (5+ CS). Without controlling for confounders, higher pollution ranks increased the odds ratio (OR) of reporting 5+ CS by 28% (p < 0.01; Confidence Interval (CI): 1.07–1.54). Females were 1.52 (p < 0.05; CI: 1.03–2.26) times more likely more likely to report 5+ CS after controlling for income, age and chronic diseases. The CART analysis showed that allergies and occupational exposure classified the sample into the most homogenous groups of males and females. The likelihood of reporting 5+ CS among females was higher after stratifying the sample based on occupational exposure. However, stratifying by allergic disease resulted in no significant sex difference in symptom reporting. The results confirmed previous research that found pre-existing health conditions to increase susceptibility to ambient air pollution, but additionally indicated that stronger effects on females is partly due to autoimmune disorders. Furthermore, gender differences in occupational exposure confound the effect size of exposure in studies based on residential levels of air pollution. PMID:23975108

Comparison of exact, efron and breslow parameter approach method on hazard ratio and stratified cox regression model

NASA Astrophysics Data System (ADS)

Fatekurohman, Mohamat; Nurmala, Nita; Anggraeni, Dian

2018-04-01

Lungs are the most important organ, in the case of respiratory system. Problems related to disorder of the lungs are various, i.e. pneumonia, emphysema, tuberculosis and lung cancer. Comparing all those problems, lung cancer is the most harmful. Considering about that, the aim of this research applies survival analysis and factors affecting the endurance of the lung cancer patient using comparison of exact, Efron and Breslow parameter approach method on hazard ratio and stratified cox regression model. The data applied are based on the medical records of lung cancer patients in Jember Paru-paru hospital on 2016, east java, Indonesia. The factors affecting the endurance of the lung cancer patients can be classified into several criteria, i.e. sex, age, hemoglobin, leukocytes, erythrocytes, sedimentation rate of blood, therapy status, general condition, body weight. The result shows that exact method of stratified cox regression model is better than other. On the other hand, the endurance of the patients is affected by their age and the general conditions.

Numerical simulation of turbulent stratified flame propagation in a closed vessel

NASA Astrophysics Data System (ADS)

Gruselle, Catherine; Lartigue, Ghislain; Pepiot, Perrine; Moureau, Vincent; D'Angelo, Yves

2012-11-01

Reducing pollutants emissions while keeping a high combustion efficiency and a low fuel consumption is an important challenge for both gas turbine (GT) and internal combustion engines (ICE). To fulfill these new constraints, stratified combustion may constitute an efficient strategy. A tabulated chemistry approach based on FPI combined to a low-Mach number method is applied in the analysis of a turbulent propane-air flame with equivalence ratio (ER) stratification, which has been studied experimentally by Balusamy [S. Balusamy, Ph.D Thesis, INSA-Rouen (2010)]. Flame topology, along with flame velocity statistics, are well reproduced in the simulation, even if time-history effects are not accounted for in the tabulated approach. However, these effects may become significant when exhaust gas recirculation (EGR) is introduced. To better quantify them, both ER and EGR-stratified two-dimensional flames are simulated using finite-rate chemistry and a semi-detailed mechanism for propane oxidation. The numerical implementation is first investigated in terms of efficiency and accuracy, with a focus on splitting errors. The resulting flames are then analyzed to investigate potential extensions of the FPI technique to EGR stratification.

The Association of Health and Functional Status with Private and Public Religious Practice among Rural, Ethnically Diverse, Older Adults with Diabetes

ERIC Educational Resources Information Center

Arcury, Thomas A.; Stafford, Jeanette M.; Bell, Ronny A.; Golden, Shannon L.; Snively, Beverly M.; Quandt, Sara A.

2007-01-01

Purpose: This analysis describes the association of health and functional status with private and public religious practice among ethnically diverse (African American, Native American, white) rural older adults with diabetes. Methods: Data were collected using a population-based, cross-sectional, stratified, random sample survey of 701…

Northeastern FIA Tree Taper Study: Current Status and Future Work

Treesearch

James A. Westfall; Charles T. Scott

2005-01-01

The northeastern unit of the Forest Inventory and Analysis program (NE-FIA) is engaged in an ongoing project to develop regionwide tree taper equations. Sampling intensity is based on NE-FIA plot data and is stratified by species, diameter class, and height class. To date, modeling research has been aimed largely at evaluating existing model forms (and hybrids thereof...

The Relevance of Objective and Subjective Social Position for Self-Rated Health: A Combined Approach for the Swedish Context

ERIC Educational Resources Information Center

Miething, Alexander

2013-01-01

The study investigates the health effects of subjective class position stratified by objective social position. Four types of subjective class were analysed separately for individuals with manual or non-manual occupational background. The cross-sectional analysis is based on the Swedish Level-of-Living Survey from 2000 and includes 4,139…

Real-time real-world analysis of seasonal influenza vaccine effectiveness: method development and assessment of a population-based cohort in Stockholm County, Sweden, seasons 2011/12 to 2014/15.

PubMed

Leval, Amy; Hergens, Maria Pia; Persson, Karin; Örtqvist, Åke

2016-10-27

Real-world estimates of seasonal influenza vaccine effectiveness (VE) are important for early detection of vaccine failure. We developed a method for evaluating real-time in-season vaccine effectiveness (IVE) and overall seasonal VE. In a retrospective, register-based, cohort study including all two million individuals in Stockholm County, Sweden, during the influenza seasons from 2011/12 to 2014/15, vaccination status was obtained from Stockholm's vaccine register. Main outcomes were hospitalisation or primary care visits for influenza (International Classification of Disease (ICD)-10 codes J09-J11). VE was assessed using Cox multivariate stratified and non-stratified analyses adjusting for age, sex, socioeconomic status, comorbidities and previous influenza vaccinations. Stratified analyses showed moderate VE in prevention of influenza hospitalisations among chronically ill adults ≥ 65 years in two of four seasons, and lower but still significant VE in one season; 53% (95% confidence interval (CI): 33-67) in 2012/13, 55% (95% CI: 25-73) in 2013/14 and 18% (95% CI: 3-31) in 2014/15. In conclusion, seasonal influenza vaccination was associated with substantial reductions in influenza-specific hospitalisation, particularly in adults ≥ 65 years with underlying chronic conditions. With the use of population-based patient register data on influenza-specific outcomes it will be possible to obtain real-time estimates of seasonal influenza VE. This article is copyright of The Authors, 2016.

Real-time real-world analysis of seasonal influenza vaccine effectiveness: method development and assessment of a population-based cohort in Stockholm County, Sweden, seasons 2011/12 to 2014/15

PubMed Central

Leval, Amy; Hergens, Maria Pia; Persson, Karin; Örtqvist, Åke

2016-01-01

Real-world estimates of seasonal influenza vaccine effectiveness (VE) are important for early detection of vaccine failure. We developed a method for evaluating real-time in-season vaccine effectiveness (IVE) and overall seasonal VE. In a retrospective, register-based, cohort study including all two million individuals in Stockholm County, Sweden, during the influenza seasons from 2011/12 to 2014/15, vaccination status was obtained from Stockholm’s vaccine register. Main outcomes were hospitalisation or primary care visits for influenza (International Classification of Disease (ICD)-10 codes J09-J11). VE was assessed using Cox multivariate stratified and non-stratified analyses adjusting for age, sex, socioeconomic status, comorbidities and previous influenza vaccinations. Stratified analyses showed moderate VE in prevention of influenza hospitalisations among chronically ill adults ≥ 65 years in two of four seasons, and lower but still significant VE in one season; 53% (95% confidence interval (CI): 33–67) in 2012/13, 55% (95% CI: 25–73) in 2013/14 and 18% (95% CI: 3–31) in 2014/15. In conclusion, seasonal influenza vaccination was associated with substantial reductions in influenza-specific hospitalisation, particularly in adults ≥ 65 years with underlying chronic conditions. With the use of population-based patient register data on influenza-specific outcomes it will be possible to obtain real-time estimates of seasonal influenza VE. PMID:27813473

Racial sexual mixing and factors associated with condom use among Middle Eastern-Canadians.

PubMed

Schoueri, Nour; Bullock, Sandra L; Dubin, Joel A

2010-02-01

Interracial relationships in Canada have increased over the years. However, little research has focused on comparing STI/HIV risk and condom use between those in intra- and interracial relationships, specifically among Middle Eastern-Canadians. A web-based survey was administered to Middle Eastern-Canadians. Logistic regression analysis was used to assess factors associated with consistent condom use. Analyses were stratified by partner's race (Middle Eastern or non-Middle Eastern). The analysis sub-sample consisted of 92 participants. Factors associated with consistent condom use varied between the stratified groups. Among those with Middle Eastern partners, attitude towards marriage and the family and control in the relationship were associated with condom use. Among participants with non-Middle Eastern partners, acculturation and HIV knowledge were found to be associated with condom use. Factors associated with condom use varied between Middle Eastern-Canadians in intra- and interracial relationships. These differences illustrate the need for tailored interventions aimed at increasing condom use among this racial group.

Study on Reform of College English Stratified Teaching Based on School-Based Characteristics

ERIC Educational Resources Information Center

Yang, Liu

2012-01-01

Considering the status quo of college English teaching, we implement stratified teaching, which reflects the idea of stratification in terms of teaching objects, teaching management, teaching process and assessment and evaluation, makes each students get development to the greatest extent in interactive teaching practice of teaching and learning…

The association between long working hours and the metabolic syndrome: evidences from the 5th Korean National Health and Nutrition Examination Survey of 2010 and 2012.

PubMed

Jeong, Jae Uk; Jeon, Man Joong; Sakong, Joon

2014-01-01

This study was conducted in order to evaluate the association between the working hours of Korean employees and the metabolic syndrome and the effects of long working hours on metabolic syndrome based on the 5th Korean National Health and Nutrition Examination Survey (2010-2012). Based on the 5th Korean National Health and Nutrition Examination Survey (2010-2012), 4,456 Korean employees without shift work, aged over 15, who work 30 hours or more per week were targeted in this study. The association between the general characteristics, including age, smoking, alcohol drinking, exercise, and the metabolic syndrome criteria defined by International Diabetes Federation (IDF) and weekly working hours were analyzed. In addition, the association between weekly working hours and the metabolic syndrome of the subjects stratified by gender was analyzed through multiple logistic regression analyses and generalized linear mixed model after adjusting the general characteristics. In the results of stratified analysis by gender, in male subjects, in comparison with the 30-39 weekly working hours group, there were no significant adjusted odds ratios to the other working hours groups. In female subjects, in comparison with the 30-39 weekly working hours group, there were no significant adjusted odds ratios to the other working hours groups. In addition, no trend associations were observed among weekly working hour groups in both stratified genders. No significant differences in prevalence of metabolic syndrome of the subjects stratified by gender were found according to weekly increasing working hours. However, due to some limitations of this study, further prospective studies may be necessary for verification.

The Association Between Body Mass Index and Open-angle Glaucoma in a South Korean Population-based Sample.

PubMed

Lin, Shuai-Chun; Pasquale, Louis R; Singh, Kuldev; Lin, Shan C

2018-03-01

The purpose of this article is to investigate the association between body mass index (BMI) and open-angle glaucoma (OAG) in a sample of the South Korean population. The sample consisted of a cross-sectional, population-based sample of 10,978 participants, 40 years of age and older, enrolled in the 2008 to 2011 Korean National Health and Nutrition Examination Survey. All participants had measured intraocular pressure <22 mm Hg and open anterior chamber angles. OAG was defined using disc and visual field criteria established by the International Society for Geographical and Epidemiological Ophthalmology. Multivariable analyses were performed to determine the association between BMI and OAG. These analyses were also performed in a sex-stratified and age-stratified manner. After adjusting for potential confounding variables, lower BMI (<19 kg/m) was associated with greater risk of OAG compared with normal BMI (19 to 24.9 kg/m) [odds ratio (OR), 2.28; 95% confidence interval (CI), 1.22-4.26]. In sex-stratified analyses, low BMI remained adversely related to glaucoma in women (OR, 3.45; 95% CI, 1.42-8.38) but not in men (OR, 1.72; 95% CI, 0.71-4.20). In age-stratified analyses, lower BMI was adversely related to glaucoma among subjects 40- to 49-year old (OR, 5.16; 95% CI, 1.86-14.36) but differences in glaucoma prevalence were not statistically significant between those with low versus normal BMI in other age strata. Lower BMI was associated with increased odds of OAG in a sample of the South Korean population. Multivariate analysis revealed the association to be statistically significant in women and those in the youngest age stratum.

International Symposium on Stratified Flows (4th) Held in Grenoble, France on June 29-July 2, 1994. Volume 2

DTIC Science & Technology

1994-10-10

G . Pawlal4 L. Arm, 11:30 Measuremtents of a turbulent patch in a rotating, 11:30 Constricted flows from the Pacific to the Indian ilnearly stratified...flow through a channel with an low-Reynolds-number convective boundary layer - underwater sill - 157 198 Z. Zhu, 6. A Lawrence G . N. Colemnan, J. H...vortex 12:15 Hydraulic control analysis of an integrated gravity interactions in stably stratified homogeneous current model - 134 turbulence - 246 ( G

Lessons learned and insights from the implementation of a food and physical activity policy to prevent obesity in Mexican schools: An analysis of nationally representative survey results.

PubMed

Théodore, Florence L; Moreno-Saracho, Jessica E; Bonvecchio, Anabelle; Morales-Ruán, María Del Carmen; Tolentino-Mayo, Lizbeth; López-Olmedo, Nancy; Shamah-Levy, Teresa; Rivera, Juan A

2018-01-01

Obesity is a serious problem among children in Mexico. In 2010, the government implemented a national food and physical activity policy in elementary schools, to prevent obesity. The goal of this study is to assess the implementation of this policy, using the logic model from a descriptive survey with national representativeness at the elementary school level and based on a stratified cluster design. We used a systematic random sampling of schools (n = 122), stratified into public and private. We administered questionnaires to 116 principals, 165 members of the Food and Physical Activity Committees, 132 food school food vendors, 119 teachers, 348 parents. This study evidences a significant deviation in implementation from what had been planned. Our lessons learned are the importance to: base the design/implementation of the policy on a theoretical framework, make programs appealing to stakeholders, select concrete and measurable objective or goals, and support stakeholders during the implementation process.

Stratification of American hearing aid users by age and audiometric characteristics: a method for representative sampling.

PubMed

Aronoff, Justin M; Yoon, Yang-soo; Soli, Sigfrid D

2010-06-01

Stratified sampling plans can increase the accuracy and facilitate the interpretation of a dataset characterizing a large population. However, such sampling plans have found minimal use in hearing aid (HA) research, in part because of a paucity of quantitative data on the characteristics of HA users. The goal of this study was to devise a quantitatively derived stratified sampling plan for HA research, so that such studies will be more representative and generalizable, and the results obtained using this method are more easily reinterpreted as the population changes. Pure-tone average (PTA) and age information were collected for 84,200 HAs acquired in 2006 and 2007. The distribution of PTA and age was quantified for each HA type and for a composite of all HA users. Based on their respective distributions, PTA and age were each divided into three groups, the combination of which defined the stratification plan. The most populous PTA and age group was also subdivided, allowing greater homogeneity within strata. Finally, the percentage of users in each stratum was calculated. This article provides a stratified sampling plan for HA research, based on a quantitative analysis of the distribution of PTA and age for HA users. Adopting such a sampling plan will make HA research results more representative and generalizable. In addition, data acquired using such plans can be reinterpreted as the HA population changes.

Turbulent mixing in stably stratified flows of the environment: The current state of the problem (Review)

NASA Astrophysics Data System (ADS)

Vasil'Ev, O. F.; Voropaeva, O. F.; Kurbatskii, A. F.

2011-06-01

Specific features of the turbulent transfer of the momentum and heat in stably stratified geophysical flows, as well as possibilities for including them into RANS turbulence models, are analyzed. The momentum (but not heat) transfer by internal gravity waves under conditions of strong stability is, for example, one such feature. Laboratory data and measurements in the atmosphere fix a clear dropping trend of the inverse turbulent Prandtl number with an increasing gradient Richardson number, which must be reproduced by turbulence models. Ignoring this feature can cause a false diffusion of heat under conditions of strong stability and lead, in particular, to noticeable errors in calculations of the temperature in the atmospheric boundary layer. Therefore, models of turbulent transfer must include the effect of the action of buoyancy and internal gravity waves on turbulent flows of the momentum. Such a strategy of modeling the stratified turbulence is presented in the review by a concrete RANS model and original results obtained during the modeling of stratified flows in the environment. Semiempirical turbulence models used for calculations of complex turbulent flows in deep stratified bodies of water are also analyzed. This part of the review is based on the data of investigations within the framework of the large international scientific Comparative Analysis and Rationalization of Second-Moment Turbulence Models (CARTUM) project and other publications of leading specialists. The most economical and effective approach associated with modified two-parameter turbulence models is a real alternative to classical variants of these models. A class of test problems and laboratory and full-scale experiments used by the participants of the CARTUM project for the approbation of numerical models are considered.

The Relationship of Family Satisfaction to Satisfaction with the Military Way of Life among Soldiers. Technical Report 864.

ERIC Educational Resources Information Center

Bowen, Gary L.

This study investigated the relationship between soldiers' satisfaction with the environment for families in the Army and satisfaction with the military way of life. The report is based on a secondary analysis of the responses of a stratified random sample of 9,198 Army personnel, a sample that participated in the 1985 Department of Defense…

Baseline characteristics predict risk of progression and response to combined medical therapy for benign prostatic hyperplasia (BPH).

PubMed

Kozminski, Michael A; Wei, John T; Nelson, Jason; Kent, David M

2015-02-01

To better risk stratify patients, using baseline characteristics, to help optimise decision-making for men with moderate-to-severe lower urinary tract symptoms (LUTS) secondary to benign prostatic hyperplasia (BPH) through a secondary analysis of the Medical Therapy of Prostatic Symptoms (MTOPS) trial. After review of the literature, we identified potential baseline risk factors for BPH progression. Using bivariate tests in a secondary analysis of MTOPS data, we determined which variables retained prognostic significance. We then used these factors in Cox proportional hazard modelling to: i) more comprehensively risk stratify the study population based on pre-treatment parameters and ii) to determine which risk strata stood to benefit most from medical intervention. In all, 3047 men were followed in MTOPS for a mean of 4.5 years. We found varying risks of progression across quartiles. Baseline BPH Impact Index score, post-void residual urine volume, serum prostate-specific antigen (PSA) level, age, American Urological Association Symptom Index score, and maximum urinary flow rate were found to significantly correlate with overall BPH progression in multivariable analysis. Using baseline factors permits estimation of individual patient risk for clinical progression and the benefits of medical therapy. A novel clinical decision tool based on these analyses will allow clinicians to weigh patient-specific benefits against possible risks of adverse effects for a given patient. © 2014 The Authors. BJU International © 2014 BJU International.

Forest inventory and stratified estimation: a cautionary note

Treesearch

John Coulston

2008-01-01

The Forest Inventory and Analysis (FIA) Program uses stratified estimation techniques to produce estimates of forest attributes. Stratification must be unbiased and stratification procedures should be examined to identify any potential bias. This note explains simple techniques for identifying potential bias, discriminating between sample bias and stratification bias,...

Numerical analysis of internal waves in stratified wake flows

NASA Astrophysics Data System (ADS)

Fraunie, Philppe

2014-05-01

In laboratory investigations, increased attention has been given to internal waves generated by stationary placed oscillating sources and moving bodies in stratified fluids [1]. The main attention was paid to study flows past bodies of perfect shapes like sphere [2], cylinder [3] of thin strip [3] which are the best theoretical (analytical or numerical) studies. Due to simplicity of geometry, flow around a strip has a potential to investigate separately effects of a drag and lift forces on the body by changing the slope of the horizontally moving strip which can be placed vertically [1], horizontally [2], or be tilted under some angle to the direction of towing velocity [5]. Numeric modeling of a flow past vertical strip uniformly towing with permanent velocity in horizontal direction in a linearly stratified talk which was based on a finite differences solver adapted to the low Reynolds Navier-Stokes equation with transport equation for salinity (LES simulation [6] and RANS [7]) has demonstrated reasonable agreement with data of Schlieren visualization, density marker and probe measurements of internal wave fields. The chosen test cases allowed demonstrating the ability of selected numerical methods to represent stably stratified flows over horizontal strip [4] and hill type 2D obstacles [1, 3] with generation of internal waves. ACKNOWLEDGMENTS This research work was supported by the Region Provence Alpes Côte d'Azur - Modtercom project. The work was also supported by the Russian Foundation for Basic Research (grant 12-01-00128). REFERENCES [1] Chashechkin Yu.D., Mitkin V.V. Experimental study of a fine structure of 2D wakes and mixing past an obstacle in a continuously stratified fluid // Dynamics of Atmosphere and Oceans. 2001. V. 34. P. 165-187. [2] Chashechkin, Yu. D. Hydrodynamics of a sphere in a stratified fluid // Fluid Dyn. 1989. V.24(1) P. 1-7. [3] Mitkin V. V., Chashechkin Yu. D. Transformation of hanging discontinuities into vortex systems in a stratified flow behind a cylinder // 2007. Fluid Dyn. V. 42 (1). P. 12-23. [4] Bardakov R. N., Mitkin V. V., Chashechkin Yu. D. Fine structure of a stratified flow near a flat-plate surface // J. Appl. Mech. Tech. Phys. 2007. V. 48(6) P. 840-851. [5] Chashechkin Yu. D., Mitkin V. V. An effect of a lift force on the structure of attached internal waves in a continuously stratified fluid // Dokl. Phys. 2001. V. 46 (6). P. 425-428. [6] Houcine H., Chashechkin Yu.D, Fraunié P., Fernando H.J.S., Gharbi A., Lili T. Numerical modeling of the generation of internal waves by uniform stratified flow over a thin vertical barrier // Int J. Num Methods in Fluids. 2012. V.68(4). P. 451-466. DOI: 10.1002/fld.2513 [7] Bodnar T., Benes , Fraunié P., Kozel K.. Application of Compact Finite-Difference Schemes to Simulations of Stably Stratified Fluid Flows. Applied Mathematics and Computation 219 : 3336-3353 2012. doi:10.1016/j.amc.2011.08.058

CerebralWeb: a Cytoscape.js plug-in to visualize networks stratified by subcellular localization.

PubMed

Frias, Silvia; Bryan, Kenneth; Brinkman, Fiona S L; Lynn, David J

2015-01-01

CerebralWeb is a light-weight JavaScript plug-in that extends Cytoscape.js to enable fast and interactive visualization of molecular interaction networks stratified based on subcellular localization or other user-supplied annotation. The application is designed to be easily integrated into any website and is configurable to support customized network visualization. CerebralWeb also supports the automatic retrieval of Cerebral-compatible localizations for human, mouse and bovine genes via a web service and enables the automated parsing of Cytoscape compatible XGMML network files. CerebralWeb currently supports embedded network visualization on the InnateDB (www.innatedb.com) and Allergy and Asthma Portal (allergen.innatedb.com) database and analysis resources. Database tool URL: http://www.innatedb.com/CerebralWeb © The Author(s) 2015. Published by Oxford University Press.

Stemflow estimation in a redwood forest using model-based stratified random sampling

Treesearch

Jack Lewis

2003-01-01

Model-based stratified sampling is illustrated by a case study of stemflow volume in a redwood forest. The approach is actually a model-assisted sampling design in which auxiliary information (tree diameter) is utilized in the design of stratum boundaries to optimize the efficiency of a regression or ratio estimator. The auxiliary information is utilized in both the...

Balance in non-hydrostatic rotating stratified turbulence

NASA Astrophysics Data System (ADS)

McKiver, William J.; Dritschel, David G.

It is now well established that two distinct types of motion occur in geophysical turbulence: slow motions associated with potential vorticity advection and fast oscillations due to inertiamaster variable this is known as balance. In real geophysical flows, deviations from balance in the form of inertiaimbalance|N/f) where optimal potential vorticity balancenonlinear quasi-geostrophic balance’ procedure expands the equations of motion to second order in Rossby number but retains the exact (unexpanded) definition of potential vorticity. This proves crucial for obtaining an accurate estimate of balanced motions. In the analysis of rotating stratified turbulence at Ro1 and N/f1, this procedure captures a significantly greater fraction of the underlying balance than standard (linear) quasi-geostrophic balance (which is based on the linearized equations about a state of rest). Nonlinear quasi-geostrophic balance also compares well with optimal potential vorticity balance, which captures the greatest fraction of the underlying balance overall.More fundamentally, the results of these analyses indicate that balance dominates in carefully initialized simulations of freely decaying rotating stratified turbulence up to O(1) Rossby numbers when N/f1. The fluid motion exhibits important quasi-geostrophic features with, in particular, typical height-to-width scale ratios remaining comparable to f/N.

Re-analysis of health and educational impacts of a school-based deworming programme in western Kenya: a statistical replication of a cluster quasi-randomized stepped-wedge trial

PubMed Central

Davey, Calum; Aiken, Alexander M; Hayes, Richard J; Hargreaves, James R

2015-01-01

Introduction: Helminth (worm) infections cause morbidity among poor communities worldwide. An influential study conducted in Kenya in 1998–99 reported that a school-based drug-and-educational intervention had benefits for worm infections and school attendance. Methods: In this statistical replication, we re-analysed data from this cluster quasi-randomized stepped-wedge trial, specifying two co-primary outcomes: school attendance and examination performance. We estimated intention-to-treat effects using year-stratified cluster-summary analysis and observation-level random-effects regression, and combined both years with a random-effects model accounting for year. The participants were not blinded to allocation status, and other interventions were concurrently conducted in a sub-set of schools. A protocol guiding outcome data collection was not available. Results: Quasi-randomization resulted in three similar groups of 25 schools. There was a substantial amount of missing data. In year-stratified cluster-summary analysis, there was no clear evidence for improvement in either school attendance or examination performance. In year-stratified regression models, there was some evidence of improvement in school attendance [adjusted odds ratios (aOR): year 1: 1.48, 95% confidence interval (CI) 0.88–2.52, P = 0.147; year 2: 1.23, 95% CI 1.01–1.51, P = 0.044], but not examination performance (adjusted differences: year 1: −0.135, 95% CI −0.323–0.054, P = 0.161; year 2: −0.017, 95% CI −0.201–0.166, P = 0.854). When both years were combined, there was strong evidence of an effect on attendance (aOR 1.82, 95% CI 1.74–1.91, P < 0.001), but not examination performance (adjusted difference −0.121, 95% CI −0.293–0.052, P = 0.169). Conclusions: The evidence supporting an improvement in school attendance differed by analysis method. This, and various other important limitations of the data, caution against over-interpretation of the results. We find that the study provides some evidence, but with high risk of bias, that a school-based drug-treatment and health-education intervention improved school attendance and no evidence of effect on examination performance. PMID:26203171

Geohydrology and water quality of stratified-drift aquifers in the middle Merrimack River basin, south-central New Hampshire

USGS Publications Warehouse

Ayotte, Joseph D.; Toppin, Kenneth W.

1995-01-01

The U.S. Geological Survey, in cooperation with the State of New Hampshire, Department of Environmental Services, Water Resources Division has assessed the geohydrology and water quality of stratified-drift aquifers in the middle Merrimack River basin in south-central New Hampshire. The middle Merrimack River basin drains 469 square miles; 98 square miles is underlain by stratified-drift aquifers. Saturated thickness of stratified drift within the study area is generally less than 40 feet but locally greater than 100 feet. Transmissivity of stratified-drift aquifers is generally less than 2,000 feet squared per day but locally exceeds 6, 000 feet squared per day. At present (1990), ground-water withdrawals from stratified drift for public supply are about 0.4 million gallons per day within the basin. Many of the stratified-drift aquifers within the study area are not developed to their fullest potential. The geohydrology of stratified-drift aquifers was investigated by focusing on basic aquifer properties, including aquifer boundaries; recharge, discharge, and direction of ground-water flow; saturated thickness and storage; and transmissivity. Surficial geologic mapping assisted in the determination of aquifer boundaries. Data from 757 wells and test borings were used to produce maps of water-table altitude, saturated thickness, and transmissivity of stratified drift. More than 10 miles of seismic-refraction profiling and 14 miles of seismic-reflection profiling were also used to construct the water table and saturated-thickness maps. Stratified-drift aquifers in the southern, western, and central parts of the study area are typically small and discontinuous, whereas aquifers in the eastern part along the Merrimack River valley are continuous. The Merrimack River valley aquifers formed in glacial Lakes Merrimack and Hooksett. Many other smaller discontinuous aquifers formed in small temporary ponds during deglaciation. A stratified-drift aquifer in Goffstown was analyzed for aquifer yield by use of a two-dimensional, finite-difference ground-water-flow model. Yield of the Goffstown aquifer was estimated to be 2.5 million gallons per day. Sensitivity analysis showed that the estimate of aquifer yield was most sensitive to changes in hydraulic conductivity. The amount of water induced into the aquifer from the Piscataquog River was most affected by changes in estimates of streambed conductance. Results of analysis of water samples from 10 test wells indicate that, with some exceptions, water in the stratified-drift aquifers generally meets U.S. Environmental Protection Agency primary and secondary drinking-water regulations. Water from two wells had elevated sodium concentrations, waterfront two wells had elevated concentrations of dissolved iron, and waterfront seven wells had elevated concentrations of manganese. Known areas of contamination were avoided during water-quality sampling.

[Challenges of an integrative and personalised health care for health economics and the insurance system].

PubMed

Schoch, Goentje-Gesine; Würdemann, E

2014-11-01

"Stratifying medicine" is a topic of increasing importance in the public health system. There are several questions related to "stratifying medicine". This paper reconsiders definitions, opportunities and risks related to "stratifying medicine" as well as the main challenges of "stratifying medicine" from the perspective of a public health insurance. The application of the term and the definition are important points to discuss. Terms such as "stratified medicine", "personalised medicine" or "individualised medicine" are used. The Techniker Krankenkasse prefers "stratifying medicine", because it usually means a medicine that tailors therapy to specific groups of patients by biomarkers. OPPORTUNITIES AND RISKS: "Stratifying medicine" is associated with various hopes, e. g., the avoidance of ineffective therapies and early detection of diseases. But "stratifying medicine" also carries risks, such as an increase in the number of cases by treatment of disease risks, a duty for health and the weakening of the criteria of evidence-based medicine. The complexity of "stratifying medicine" is a big challenge for all involved parties in the health system. A lot of interrelations are still not completely understood. So the statutory health insurance faces the challenge of making innovative therapy concepts accessible in a timely manner to all insured on the one hand but on the other hand also to protect the community from harmful therapies. Information and advice to patients related to "stratifying medicine" is of particular importance. The equitable distribution of fees for diagnosis and counselling presents a particular challenge. The solidarity principle of public health insurance may be challenged by social and ethical issues of "stratifying medicine". "Stratifying medicine" offers great potential to improve medical care. However, false hopes must be avoided. Providers and payers should measure chances and risks of "stratifying medicine" together for the welfare of the patients. © Georg Thieme Verlag KG Stuttgart · New York.

Stratified flows in complex terrain

NASA Astrophysics Data System (ADS)

Retallack, Charles

The focus of this dissertation is the study of stratified atmospheric flows in the presence of complex terrain. Two large-scale field study campaigns were carried out, each with a focus on a specific archetypal terrain. Each field study involved the utilization of remote and in-situ atmospheric monitoring devices to collect experimental data. The first of the two field studies focused on pollution transport mechanisms near an escarpment. The analysis aimed to determine the combined effect of the escarpment and ambient density stratification on the flow and aerosol pollution transport. It was found that under specific atmospheric conditions, the escarpment prompted the channeling, down-mixing, and trapping of aerosol pollutant plumes. The objective of the second field campaign was the study of stratified flows in a mountain valley. Analysis revealed that buoyancy driven katabatic currents originating on the surrounding valley slopes created a scenario in which a down-slope gravity current transitioned into an intrusive gravity current. The intrusive gravity current propagated near the interface of a density stratified lower ambient layer and a non-stratified upper ambient layer. A combination of shallow water theory and energy arguments is used to produce a model for the propagation of a gravity current moving along the interface of a homogeneous ambient layer and a linearly stratified layer. It is found that the gravity current propagating entirely within the homogeneous layer travels at the greatest speed. As the relative density of the gravity current is increased, the gravity current begins to slump below the interface of the two layers and the propagation speed decreases.

Recurrence networks from multivariate signals for uncovering dynamic transitions of horizontal oil-water stratified flows

NASA Astrophysics Data System (ADS)

Gao, Zhong-Ke; Zhang, Xin-Wang; Jin, Ning-De; Donner, Reik V.; Marwan, Norbert; Kurths, Jürgen

2013-09-01

Characterizing the mechanism of drop formation at the interface of horizontal oil-water stratified flows is a fundamental problem eliciting a great deal of attention from different disciplines. We experimentally and theoretically investigate the formation and transition of horizontal oil-water stratified flows. We design a new multi-sector conductance sensor and measure multivariate signals from two different stratified flow patterns. Using the Adaptive Optimal Kernel Time-Frequency Representation (AOK TFR) we first characterize the flow behavior from an energy and frequency point of view. Then, we infer multivariate recurrence networks from the experimental data and investigate the cross-transitivity for each constructed network. We find that the cross-transitivity allows quantitatively uncovering the flow behavior when the stratified flow evolves from a stable state to an unstable one and recovers deeper insights into the mechanism governing the formation of droplets at the interface of stratified flows, a task that existing methods based on AOK TFR fail to work. These findings present a first step towards an improved understanding of the dynamic mechanism leading to the transition of horizontal oil-water stratified flows from a complex-network perspective.

The utility of presacral drainage in penetrating rectal injuries in adult and pediatric patients.

PubMed

Savoie, Kate B; Beazley, Thomas M; Cleveland, Brent; Khaneki, Sina; Markel, Troy A; Hammer, Peter M; Savage, Stephanie; Williams, Regan F

2017-11-01

With changing weaponry associated with injuries in civilian trauma, there is no clinical census on the utility of presacral drainage (PSD) in penetrating rectal injuries (PRIs), particularly in pediatric patients. Patients with PRI from July 2004-June 2014 treated at two free-standing children's hospitals and two adult level 1 trauma centers were compared by age (pediatric patients ≤16 years) and PSD. A stratified analysis was performed based on age. The primary outcome was pelvic/presacral abscess. We identified 81 patients with PRI; 19 pediatric, 62 adult. Forty patients had PSD; only three pediatric patients had a drain. Adult patients were more likely to have sustained gunshot wounds (84%), whereas pediatric patients were more likely to sustain impalement injuries (59%). Pediatric patients were more likely to have distal extraperitoneal injuries (56% versus 27% in adults, P = 0.03). PSD was more common in adult patients (59% versus 14%, P = 0.0004), African-Americans (71% versus 11% Caucasian, P < 0.01), and those sustaining gun shot wounds (63% versus 18% impalement, P < 0.01); only race remained significant in stratified analysis for both adult and pediatric patients. There were three cases of pelvic/presacral abscess, all in the adult patients (P = 0.31); one patient with PSD and two without PSD (P = 0.58). In stratified analysis, there were no differences in any infectious complication between those with and without PSD. Pelvic/presacral abscess is a rare complication of PRI, especially in pediatric patients. PSD is not associated with decreased rates of infectious complications and may not be necessary in the treatment of PRI. Copyright © 2017 Elsevier Inc. All rights reserved.

Quantum image pseudocolor coding based on the density-stratified method

NASA Astrophysics Data System (ADS)

Jiang, Nan; Wu, Wenya; Wang, Luo; Zhao, Na

2015-05-01

Pseudocolor processing is a branch of image enhancement. It dyes grayscale images to color images to make the images more beautiful or to highlight some parts on the images. This paper proposes a quantum image pseudocolor coding scheme based on the density-stratified method which defines a colormap and changes the density value from gray to color parallel according to the colormap. Firstly, two data structures: quantum image GQIR and quantum colormap QCR are reviewed or proposed. Then, the quantum density-stratified algorithm is presented. Based on them, the quantum realization in the form of circuits is given. The main advantages of the quantum version for pseudocolor processing over the classical approach are that it needs less memory and can speed up the computation. Two kinds of examples help us to describe the scheme further. Finally, the future work are analyzed.

Web-based thyroid imaging reporting and data system: Malignancy risk of atypia of undetermined significance or follicular lesion of undetermined significance thyroid nodules calculated by a combination of ultrasonography features and biopsy results.

PubMed

Choi, Young Jun; Baek, Jung Hwan; Shin, Jung Hee; Shim, Woo Hyun; Kim, Seon-Ok; Lee, Won-Hong; Song, Dong Eun; Kim, Tae Yong; Chung, Ki-Wook; Lee, Jeong Hyun

2018-05-13

The purpose of this study was to construct a web-based predictive model using ultrasound characteristics and subcategorized biopsy results for thyroid nodules of atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) to stratify the risk of malignancy. Data included 672 thyroid nodules from 656 patients from a historical cohort. We analyzed ultrasound images of thyroid nodules and biopsy results according to nuclear atypia and architectural atypia. Multivariate logistic regression analysis was performed to predict whether nodules were diagnosed as malignant or benign. The ultrasound features, including spiculated margin, marked hypoechogenicity, calcifications, biopsy results, and cytologic atypia, showed significant differences between groups. A 13-point risk scoring system was developed, and the area under the curve (AUC) of the receiver operating characteristic (ROC) curve of the development and validation sets were 0.837 and 0.830, respectively (http://www.gap.kr/thyroidnodule_b3.php). We devised a web-based predictive model using the combined information of ultrasound characteristics and biopsy results for AUS/FLUS thyroid nodules to stratify the malignant risk. © 2018 Wiley Periodicals, Inc.

Domain Growth Kinetics in Stratifying Foam Films

NASA Astrophysics Data System (ADS)

Zhang, Yiran; Sharma, Vivek

2015-03-01

Baking bread, brewing cappuccino, pouring beer, washing dishes, shaving, shampooing, whipping eggs and blowing bubbles all involve creation of aqueous foam films. Typical foam films consist of two surfactant-laden surfaces that are μ 5 nm - 10 micron apart. Sandwiched between these interfacial layers is a fluid that drains primarily under the influence of viscous and interfacial forces, including disjoining pressure. Interestingly, for certain low molecular weight surfactants, a layered ordering of micelles inside the foam films (thickness <100 nm) leads to a stepwise thinning phenomena called stratification. We experimentally elucidate the influence of these different driving forces, and confinement on drainage kinetics of horizontal stratifying foam films. Thinner, darker domains spontaneously grow within foam films. Quantitative characterization of domain growth visualized in a using Scheludko-type thin film cell and a theoretical model based on lubrication analysis, provide critical insights into hydrodynamics of thin foam films, and the strength and nature of surface forces, including supramolecular oscillatory structural forces.

Hydrodynamics of stratified epithelium: Steady state and linearized dynamics

NASA Astrophysics Data System (ADS)

Yeh, Wei-Ting; Chen, Hsuan-Yi

2016-05-01

A theoretical model for stratified epithelium is presented. The viscoelastic properties of the tissue are assumed to be dependent on the spatial distribution of proliferative and differentiated cells. Based on this assumption, a hydrodynamic description of tissue dynamics at the long-wavelength, long-time limit is developed, and the analysis reveals important insights into the dynamics of an epithelium close to its steady state. When the proliferative cells occupy a thin region close to the basal membrane, the relaxation rate towards the steady state is enhanced by cell division and cell apoptosis. On the other hand, when the region where proliferative cells reside becomes sufficiently thick, a flow induced by cell apoptosis close to the apical surface enhances small perturbations. This destabilizing mechanism is general for continuous self-renewal multilayered tissues; it could be related to the origin of certain tissue morphology, tumor growth, and the development pattern.

VERTICAL DIFFUSION IN SMALL STRATIFIED LAKES: DATA AND ERROR ANALYSIS

EPA Science Inventory

Water temperature profiles were measured at 2-min intervals in a stratified temperate lake with a surface area of 0.06 km2 and a aximum depth of 10 m from May 7 to August 9, 1989. he data were used to calculate the vertical eddy diffusion coefficient K2 in the hypolimnion. he dep...

Analysis of Wave Propagation in Stratified Structures Using Circuit Analogues, with Application to Electromagnetic Absorbers

ERIC Educational Resources Information Center

Sjoberg, Daniel

2008-01-01

This paper presents an overview of how circuit models can be used for analysing wave propagation in stratified structures. Relatively complex structures can be analysed using models which are accessible to undergraduate students. Homogeneous slabs are modelled as transmission lines, and thin sheets between the slabs are modelled as lumped…

Implementing a land cover stratification on-the-fly

Treesearch

Ronald E. McRoberts; Daniel G. Wendt

2002-01-01

Stratified estimation is used by the Forest Inventory and Analysis program of the USDA Forest Service to increase the precision of county-level inventory estimates. Stratified estimation requires that plots be assigned to strata and that proportions of land area in each strata be determined. Classified satellite imagery has been found to be an efficient and effective...

Decision tree analysis to stratify risk of de novo non-melanoma skin cancer following liver transplantation.

PubMed

Tanaka, Tomohiro; Voigt, Michael D

2018-03-01

Non-melanoma skin cancer (NMSC) is the most common de novo malignancy in liver transplant (LT) recipients; it behaves more aggressively and it increases mortality. We used decision tree analysis to develop a tool to stratify and quantify risk of NMSC in LT recipients. We performed Cox regression analysis to identify which predictive variables to enter into the decision tree analysis. Data were from the Organ Procurement Transplant Network (OPTN) STAR files of September 2016 (n = 102984). NMSC developed in 4556 of the 105984 recipients, a mean of 5.6 years after transplant. The 5/10/20-year rates of NMSC were 2.9/6.3/13.5%, respectively. Cox regression identified male gender, Caucasian race, age, body mass index (BMI) at LT, and sirolimus use as key predictive or protective factors for NMSC. These factors were entered into a decision tree analysis. The final tree stratified non-Caucasians as low risk (0.8%), and Caucasian males > 47 years, BMI < 40 who did not receive sirolimus, as high risk (7.3% cumulative incidence of NMSC). The predictions in the derivation set were almost identical to those in the validation set (r 2  = 0.971, p < 0.0001). Cumulative incidence of NMSC in low, moderate and high risk groups at 5/10/20 year was 0.5/1.2/3.3, 2.1/4.8/11.7 and 5.6/11.6/23.1% (p < 0.0001). The decision tree model accurately stratifies the risk of developing NMSC in the long-term after LT.

Hydrogeology and water quality of the Pepacton Reservoir Watershed in Southeastern New York. Part 2. Hydrogeology, stream base flow, and ground-water recharge

USGS Publications Warehouse

Reynolds, R.J.

2004-01-01

The hydrogeology of the 372-square-mile Pepacton Reservoir watershed (herein called the East Branch Delaware River Basin) in the southwestern Catskill Mountain region of Southeastern New York is described and depicted in a detailed surficial geologic map and two geologic sections. An analysis of stream discharge records and estimates of mean annual ground-water recharge and stream base flow for eight subbasins in the basin are included.Analysis of surficial geologic data indicates that the most widespread geologic unit within the basin is till, which occurs as masses of ablation till in major stream valleys and as thick deposits of lodgment till that fill upland basins. Till covers about 91.5 percent of the Pepacton Reservoir watershed, whereas stratified drift (alluvium, outwash, and ice-contact deposits) accounts for 6.3 percent. The Pepacton Reservoir occupies about 2.3 percent of the basin area. Large outwash and ice-contact deposits occupy the valleys of the upper East Branch Delaware River, the Tremper Kill, the Platte Kill, the Bush Kill, and Dry Brook. These deposits form stratified-drift aquifers that range in thickness from 90 feet in parts of the upper East Branch Delaware River Valley to less than 30 feet in the Dry Brook valley, and average about 50 feet in the main East Branch Delaware River Valley near Margaretville.An analysis of daily mean stream discharge for the six eastern subbasins for 1998–2001, and for two western subbasins for 1945–52, was performed using three computer programs to obtain estimates of mean annual base flow and mean annual ground-water recharge for the eight subbasins. Mean annual base flow ranged from 15.3 inches per year for the Tremper Kill subbasin to 22.3 inches per year for the Mill Brook subbasin; the latter reflects the highest mean annual precipitation of all the subbasins studied. Estimated mean annual ground-water recharge ranged from 24.3 inches per year for Mill Brook to 15.8 inches per year for the Tremper Kill. The base flow index, which is the mean annual base flow expressed as a percentage of mean annual streamflow, ranged from 69.1 percent for Coles Clove Kill to 75.6 percent for the upper East Branch Delaware River; most subbasin indices were greater than 70 percent. These high base flow indices indicate that because stratified drift covers only a small percentage of subbasin areas (generally 5 to 7 percent), most of the base flow is derived from the fractured sandstone bedrock that underlies the basin.

The effectiveness of a stratified care model for non-specific low back pain in Danish primary care compared to current practice: study protocol of a randomised controlled trial.

PubMed

Morso, Lars; Schiøttz-Christensen, Berit; Søndergaard, Jens; Andersen, Nils-Bo de Vos; Pedersen, Flemming; Olsen, Kim Rose; Jensen, Morten Sall; Hill, Jonathan; Christiansen, David Høyrup

2018-06-08

Prior studies indicate that stratified care for low back pain results in better clinical outcome and reduced costs in healthcare compared to current practice. Stratified care may be associated with clinical benefits for patients with low back pain at a lower cost, but evidence is sparse. Hence this study aims to evaluate the clinical effects and cost-effectiveness of stratified care in patients with non-specific low back pain compared to current practice. The study is a two-armed randomised controlled trial in primary care in the Regions of Southern and Central Denmark (2.5 million citizens). Patients with non-specific low back will be recruited by paticpating GPs. Patients are randomised to either (1) stratified care or (2) current practice at participating physiotherapy clinics. In the stratified care arm, the intervention is based on the patient's STarT Back Tool classification and trained accordingly, whereas physiotherapists in the current pratice arm are blinded to the STarT score. Primary outcomes in the trial will be group differences in time off work, improvement in LBP disability measured by the Roland Morris Disability Questionnaire (RMDQ) and patient-reported global change. Secondary measures will be pain intensity, patient satisfaction, data on patient healthcare resource utilisation and quality-adjusted life year based on the EQ-5D-5L. Stratified care that effectively targets treatment to relevant sub-groups of patients has potentially great impact on the treatment pathways of low back pain. Thus, if effective, this could result in better patient outcomes and at the same time reduce the costs for treatment of low back pain. ClinicalTrials.gov , NCT02612467 . Registered on 16 November 2015.

Degradation of organic dyes using spray deposited nanocrystalline stratified WO3/TiO2 photoelectrodes under sunlight illumination

NASA Astrophysics Data System (ADS)

Hunge, Y. M.; Yadav, A. A.; Mahadik, M. A.; Bulakhe, R. N.; Shim, J. J.; Mathe, V. L.; Bhosale, C. H.

2018-02-01

The need to utilize TiO2 based metal oxide hetero nanostructures for the degradation of environmental pollutants like Rhodamine B and reactive red 152 from the wastewater using stratified WO3/TiO2 catalyst under sunlight illumination. WO3, TiO2 and stratified WO3/TiO2 catalysts were prepared by a spray pyrolysis method. It was found that the stratified WO3/TiO2 heterostructure has high crystallinity, no mixed phase formation occurs, strong optical absorption in the visible region of the solar spectrum, and large surface area. The photocatalytic activity was tested for degradation of Rhodamine B (Rh B) and reactive red 152 in an aqueous medium. TiO2 layer in stratified WO3/TiO2 catalyst helps to extend its absorption spectrum in the solar light region. Rh B and Reactive red 152is eliminated up to 98 and 94% within the 30 and 40 min respectively at optimum experimental condition by stratified WO3/TiO2. Moreover, stratified WO3/TiO2 photoelectrode has good stability and reusability than individual TiO2 and WO3 thin film in the degradation of Rh B and reactive red 152. The photoelectrocatalytic experimental results indicate that stratified WO3/TiO2 photoelectrode is a promising material for dye removal.

Validation of 1-hour post-thyroidectomy parathyroid hormone level in predicting hypocalcemia

PubMed Central

2014-01-01

Background Prior work by our group suggested that a single one hour post-thyroidectomy parathyroid hormone (1 hr PTH) level could accurately stratify patients into high and low risk groups for the development of hypocalcemia. This study looks to validate the safety and efficacy of a protocol based on a 1 hr PTH threshold of 12 pg/ml. Study design Retrospective analysis of consecutive cohort treated with standardized protocol. Methods One hundred and twenty five consecutive patients underwent total or completion thyroidectomy and their PTH level was drawn 1-hour post operatively. Based on our previous work, patients were stratified into either a low risk group (PTH < 12 pg/ml) or a high risk group (PTH ≥ 12 pg/ml). Patients in the high risk group were immediately started on prophylactic calcium carbonate (5–10 g/d) and calcitriol (0.5-1.0 mcg/d). The outcomes were then reviewed focusing mainly on how many low risk patients developed hypocalcemia (false negative rate), and how many high risk patients failed prophylactic therapy. Results Thirty one patients (25%) were stratified as high risk, and 94 (75%) as low risk. Five (16%) of the high risk patients became hypocalcemic despite prophylactic therapy. Two of the low risk group became hypocalcemic, (negative predictive value = 98%). None of the hypocalcemic patients had anything more than mild symptoms. Conclusions A single 1-hour post-thyroidectomy PTH level is a very useful way to stratify thyroidectomy patients into high and low risk groups for development of hypocalcemia. Early implementation of oral prophylactic calcium and vitamin D in the high risk patients is a very effective way to prevent serious hypocalcemia. Complex protocols requiring multiple calcium and PTH measurements are not required to guide post-thyroidectomy management. PMID:24476535

Stratified Whole Genome Linkage Analysis of Chiari Type I Malformation Implicates Known Klippel-Feil Syndrome Genes as Putative Disease Candidates

PubMed Central

Markunas, Christina A.; Soldano, Karen; Dunlap, Kaitlyn; Cope, Heidi; Asiimwe, Edgar; Stajich, Jeffrey; Enterline, David; Grant, Gerald; Fuchs, Herbert

2013-01-01

Chiari Type I Malformation (CMI) is characterized by displacement of the cerebellar tonsils below the base of the skull, resulting in significant neurologic morbidity. Although multiple lines of evidence support a genetic contribution to disease, no genes have been identified. We therefore conducted the largest whole genome linkage screen to date using 367 individuals from 66 families with at least two individuals presenting with nonsyndromic CMI with or without syringomyelia. Initial findings across all 66 families showed minimal evidence for linkage due to suspected genetic heterogeneity. In order to improve power to localize susceptibility genes, stratified linkage analyses were performed using clinical criteria to differentiate families based on etiologic factors. Families were stratified on the presence or absence of clinical features associated with connective tissue disorders (CTDs) since CMI and CTDs frequently co-occur and it has been proposed that CMI patients with CTDs represent a distinct class of patients with a different underlying disease mechanism. Stratified linkage analyses resulted in a marked increase in evidence of linkage to multiple genomic regions consistent with reduced genetic heterogeneity. Of particular interest were two regions (Chr8, Max LOD = 3.04; Chr12, Max LOD = 2.09) identified within the subset of “CTD-negative” families, both of which harbor growth differentiation factors (GDF6, GDF3) implicated in the development of Klippel-Feil syndrome (KFS). Interestingly, roughly 3–5% of CMI patients are diagnosed with KFS. In order to investigate the possibility that CMI and KFS are allelic, GDF3 and GDF6 were sequenced leading to the identification of a previously known KFS missense mutation and potential regulatory variants in GDF6. This study has demonstrated the value of reducing genetic heterogeneity by clinical stratification implicating several convincing biological candidates and further supporting the hypothesis that multiple, distinct mechanisms are responsible for CMI. PMID:23620759

Health care professionals' attitudes towards population-based genetic testing and risk-stratification for ovarian cancer: a cross-sectional survey.

PubMed

Hann, Katie E J; Fraser, Lindsay; Side, Lucy; Gessler, Sue; Waller, Jo; Sanderson, Saskia C; Freeman, Madeleine; Jacobs, Ian; Lanceley, Anne

2017-12-16

Ovarian cancer is usually diagnosed at a late stage when outcomes are poor. Personalised ovarian cancer risk prediction, based on genetic and epidemiological information and risk stratified management in adult women could improve outcomes. Examining health care professionals' (HCP) attitudes to ovarian cancer risk stratified management, willingness to support women, self-efficacy (belief in one's own ability to successfully complete a task), and knowledge about ovarian cancer will help identify training needs in anticipation of personalised ovarian cancer risk prediction being introduced. An anonymous survey was distributed online to HCPs via relevant professional organisations in the UK. Kruskal-Wallis tests and pairwise comparisons were used to compare knowledge and self-efficacy scores between different types of HCPs, and attitudes toward population-based genetic testing and risk stratified management were described. Content analysis was undertaken of free text responses concerning HCPs willingness to discuss risk management options with women. One hundred forty-six eligible HCPs completed the survey: oncologists (31%); genetics clinicians (30%); general practitioners (22%); gynaecologists (10%); nurses (4%); and 'others'. Scores for knowledge of ovarian cancer and genetics, and self-efficacy in conducting a cancer risk consultation were generally high but significantly lower for general practitioners compared to genetics clinicians, oncologists, and gynaecologists. Support for population-based genetic testing was not high (<50%). Attitudes towards ovarian cancer risk stratification were mixed, although the majority of participants indicated a willingness to discuss management options with patients. Larger samples are required to investigate attitudes to population-based genetic testing for ovarian cancer risk and to establish why some HCPs are hesitant to offer testing to all adult female patients. If ovarian cancer risk assessment using genetic testing and non-genetic information including epidemiological information is rolled out on a population basis, training will be needed for HCPs in primary care to enable them to provide appropriate support to women at each stage of the process.

Sampling Strategies for Evaluating the Rate of Adventitious Transgene Presence in Non-Genetically Modified Crop Fields.

PubMed

Makowski, David; Bancal, Rémi; Bensadoun, Arnaud; Monod, Hervé; Messéan, Antoine

2017-09-01

According to E.U. regulations, the maximum allowable rate of adventitious transgene presence in non-genetically modified (GM) crops is 0.9%. We compared four sampling methods for the detection of transgenic material in agricultural non-GM maize fields: random sampling, stratified sampling, random sampling + ratio reweighting, random sampling + regression reweighting. Random sampling involves simply sampling maize grains from different locations selected at random from the field concerned. The stratified and reweighting sampling methods make use of an auxiliary variable corresponding to the output of a gene-flow model (a zero-inflated Poisson model) simulating cross-pollination as a function of wind speed, wind direction, and distance to the closest GM maize field. With the stratified sampling method, an auxiliary variable is used to define several strata with contrasting transgene presence rates, and grains are then sampled at random from each stratum. With the two methods involving reweighting, grains are first sampled at random from various locations within the field, and the observations are then reweighted according to the auxiliary variable. Data collected from three maize fields were used to compare the four sampling methods, and the results were used to determine the extent to which transgene presence rate estimation was improved by the use of stratified and reweighting sampling methods. We found that transgene rate estimates were more accurate and that substantially smaller samples could be used with sampling strategies based on an auxiliary variable derived from a gene-flow model. © 2017 Society for Risk Analysis.

Catholic High Schools and Their Finances. 1986.

ERIC Educational Resources Information Center

Augenstein, John J.

This report is based on a randomly selected and stratified sample of 208 United States Catholic high schools. The sample was stratified by governance (diocesan, parochial/interparochial, and private); five categories of enrollment; and six regions. Data are compared with an earlier study, "The Catholic High School: A National Portrait" and show…

Reconstruction of refractive index profile of a stratified medium

NASA Astrophysics Data System (ADS)

Vogelzang, E.; Ferwerda, H. A.; Yevick, D.

In this paper, a method for determining the permittivity profile of a stratified medium terminated by a perfect conductor from the (complex) reflectivity is presented. The calculations are based on the Gelfand-Levitan and the Marchenko equations. The bound modes of the system are explicitly taken into account.

Periodicity of the density wake past a vortex ring in a stratified liquid

NASA Astrophysics Data System (ADS)

Prokhorov, V.

2009-04-01

Spatial coherent structure of the density wake past a vortex ring moving horizontally in viscid stratified liquid is experimentally revealed. It follows from analysis that repetition period of the structure is determined by rotation radial frequency (or mean vorticity) of the vortex core and toward speed of the vortex ring. The wake formation of the ring is considered in respect to vorticity shedding which produces velocity disturbances in ambient medium. In case of stratified liquid velocity fluctuations, in their turn, cause density field distortion. This process is superimposed by vortex core oscillations, and, in result, vorticity shedding will be not monotonous but modulated at some frequency. So, the density wake is periodically structured, and the spatial period is defined by intrinsic frequency of the core and forward speed of the ring. To support analysis, experiments were conducted in which vortex rings excited by spring-piston generator were observed with high-sensitive Schlieren instrument and computer-controlled camera. Experimental tank was filled with salt-stratified water of constant buoyancy period, vortex ring velocities range from 3 to 16 cm/s. Spatial period is derived from schlieren image using two independent methods, both 2D spectral analysis and geometry calculations of the vortex core. Spatial periods and vortex intrinsic frequencies calculated by both algorithms are in good agreement; they vary in power lows depending on vortex speed

Damage localization and quantification of composite stratified beam Structures using residual force method

NASA Astrophysics Data System (ADS)

Behtani, A.; Bouazzouni, A.; Khatir, S.; Tiachacht, S.; Zhou, Y.-L.; Abdel Wahab, M.

2017-05-01

In this paper, the problem of using measured modal parameters to detect and locate damage in beam composite stratified structures with four layers of graphite/epoxy [0°/902°/0°] is investigated. A technique based on the residual force method is applied to composite stratified structure with different boundary conditions, the results of damage detection for several damage cases demonstrate that using residual force method as damage index, the damage location can be identified correctly and the damage extents can be estimated as well.

Language with Character: A Stratified Corpus Comparison of Individual Differences in E-Mail Communication

ERIC Educational Resources Information Center

Oberlander, Jon; Gill, Alastair J.

2006-01-01

To what extent does the wording and syntactic form of people's writing reflect their personalities? Using a bottom-up stratified corpus comparison, rather than the top-down content analysis techniques that have been used before, we examine a corpus of e-mail messages elicited from individuals of known personality, as measured by the Eysenck…

Experimental analysis of an oblique turbulent flame front propagating in a stratified flow

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

Galizzi, C.; Escudie, D.

2010-12-15

This paper details the experimental study of a turbulent V-shaped flame expanding in a nonhomogeneous premixed flow. Its aim is to characterize the effects of stratification on turbulent flame characteristics. The setup consists of a stationary V-shaped flame stabilized on a rod and expanding freely in a lean premixed methane-air flow. One of the two oblique fronts interacts with a stratified slice, which has an equivalence ratio close to one and a thickness greater than that of the flame front. Several techniques such as PIV and CH{sup *} chemiluminescence are used to investigate the instantaneous fields, while laser Doppler anemometrymore » and thermocouples are combined with a concentration probe to provide information on the mean fields. First, in order to provide a reference, the homogeneous turbulent case is studied. Next, the stratified turbulent premixed flame is investigated. Results show significant modifications of the whole flame and of the velocity field upstream of the flame front. The analysis of the geometric properties of the stratified flame indicates an increase in flame brush thickness, closely related to the local equivalence ratio. (author)« less

Simulation model of stratified thermal energy storage tank using finite difference method

NASA Astrophysics Data System (ADS)

Waluyo, Joko

2016-06-01

Stratified TES tank is normally used in the cogeneration plant. The stratified TES tanks are simple, low cost, and equal or superior in thermal performance. The advantage of TES tank is that it enables shifting of energy usage from off-peak demand for on-peak demand requirement. To increase energy utilization in a stratified TES tank, it is required to build a simulation model which capable to simulate the charging phenomenon in the stratified TES tank precisely. This paper is aimed to develop a novel model in addressing the aforementioned problem. The model incorporated chiller into the charging of stratified TES tank system in a closed system. The model was developed in one-dimensional type involve with heat transfer aspect. The model covers the main factors affect to degradation of temperature distribution namely conduction through the tank wall, conduction between cool and warm water, mixing effect on the initial flow of the charging as well as heat loss to surrounding. The simulation model is developed based on finite difference method utilizing buffer concept theory and solved in explicit method. Validation of the simulation model is carried out using observed data obtained from operating stratified TES tank in cogeneration plant. The temperature distribution of the model capable of representing S-curve pattern as well as simulating decreased charging temperature after reaching full condition. The coefficient of determination values between the observed data and model obtained higher than 0.88. Meaning that the model has capability in simulating the charging phenomenon in the stratified TES tank. The model is not only capable of generating temperature distribution but also can be enhanced for representing transient condition during the charging of stratified TES tank. This successful model can be addressed for solving the limitation temperature occurs in charging of the stratified TES tank with the absorption chiller. Further, the stratified TES tank can be charged with the cooling energy of absorption chiller that utilizes from waste heat from gas turbine of the cogeneration plant.

A Stratified Acoustic Model Accounting for Phase Shifts for Underwater Acoustic Networks

PubMed Central

Wang, Ping; Zhang, Lin; Li, Victor O. K.

2013-01-01

Accurate acoustic channel models are critical for the study of underwater acoustic networks. Existing models include physics-based models and empirical approximation models. The former enjoy good accuracy, but incur heavy computational load, rendering them impractical in large networks. On the other hand, the latter are computationally inexpensive but inaccurate since they do not account for the complex effects of boundary reflection losses, the multi-path phenomenon and ray bending in the stratified ocean medium. In this paper, we propose a Stratified Acoustic Model (SAM) based on frequency-independent geometrical ray tracing, accounting for each ray's phase shift during the propagation. It is a feasible channel model for large scale underwater acoustic network simulation, allowing us to predict the transmission loss with much lower computational complexity than the traditional physics-based models. The accuracy of the model is validated via comparisons with the experimental measurements in two different oceans. Satisfactory agreements with the measurements and with other computationally intensive classical physics-based models are demonstrated. PMID:23669708

A stratified acoustic model accounting for phase shifts for underwater acoustic networks.

PubMed

Wang, Ping; Zhang, Lin; Li, Victor O K

2013-05-13

Accurate acoustic channel models are critical for the study of underwater acoustic networks. Existing models include physics-based models and empirical approximation models. The former enjoy good accuracy, but incur heavy computational load, rendering them impractical in large networks. On the other hand, the latter are computationally inexpensive but inaccurate since they do not account for the complex effects of boundary reflection losses, the multi-path phenomenon and ray bending in the stratified ocean medium. In this paper, we propose a Stratified Acoustic Model (SAM) based on frequency-independent geometrical ray tracing, accounting for each ray's phase shift during the propagation. It is a feasible channel model for large scale underwater acoustic network simulation, allowing us to predict the transmission loss with much lower computational complexity than the traditional physics-based models. The accuracy of the model is validated via comparisons with the experimental measurements in two different oceans. Satisfactory agreements with the measurements and with other computationally intensive classical physics-based models are demonstrated.

Increased Rate of Poor Laryngoscopic Views in Patients Scheduled for Cardiac Surgery Versus Patients Scheduled for General Surgery: A Propensity Score-Based Analysis of 21,561 Cases.

PubMed

Heinrich, Sebastian; Ackermann, Andreas; Prottengeier, Johannes; Castellanos, Ixchel; Schmidt, Joachim; Schüttler, Jürgen

2015-12-01

Former analyses reported an increased rate of poor direct laryngoscopy view in cardiac surgery patients; however, these findings frequently could be attributed to confounding patient characteristics. In most of the reported cardiac surgery cohorts, the rate of well-known risk factors for poor direct laryngoscopy view such as male sex, obesity, or older age, were increased compared with the control groups. Especially in the ongoing debate on anesthesia staff qualification for cardiac interventions outside the operating room a detailed and stratified risk analysis seems necessary. Retrospective, anonymous, propensity score-based, matched-pair analysis. Single-center study in a university hospital. No active participants. Retrospective, anonymous chart analysis. The anesthesia records of patients undergoing cardiac surgery in a period of 6 consecutive years were analyzed retrospectively. The results were compared with those of a control group of patients who underwent general surgery. Poor laryngoscopic view was defined as Cormack and Lehane classification grade 3 or 4. The records of 21,561 general anesthesia procedures were reviewed for the study. The incidence of poor direct laryngoscopic views in patients scheduled for cardiac surgery was significantly increased compared with those of the general surgery cohort (7% v 4.2%). Using propensity score-based matched-pair analysis, equal subgroups were generated of each surgical department, with 2,946 patients showing identical demographic characteristics. After stratifying for demographic characteristics, the rate of poor direct laryngoscopy view remained statistically significantly higher in the cardiac surgery group (7.5% v 5.7%). Even with stratification for demographic risk factors, cardiac surgery patients showed a significantly higher rate of poor direct laryngoscopic view compared with general surgery patients. These results should be taken into account for human resource management and distribution of difficult airway equipment, especially when cardiac interventional programs are implemented in remote hospital locations. Copyright © 2015 Elsevier Inc. All rights reserved.

The Utility of Discriminant Analysis for Predicting Farmers' Intentions to Participate in Farmer-Managed Irrigation Systems in Iran

NASA Astrophysics Data System (ADS)

Zarafshani, Kiumars; Hossien Alibaygi, Amir; Afshar, Nasrin

Participatory irrigation management has been problematic in most parts of the world and Iran has been no exception. The purpose of this study was to assess farmers' intentions to participate in irrigation management based on selected variables using discriminant analysis. A survey questionnaire was used to collect information from a sample of Water Cooperatives in Javanrood Townships using stratified random sampling (n = 106). Results indicated that age, educational level, attitude towards PIM, irrigation performance, landholding size, agricultural and non-agricultural income affected farmers' intentions to participate in irrigation management.

Mapping permafrost in the boreal forest with Thematic Mapper satellite data

NASA Technical Reports Server (NTRS)

Morrissey, L. A.; Strong, L. L.; Card, D. H.

1986-01-01

A geographic data base incorporating Landsat TM data was used to develop and evaluate logistic discriminant functions for predicting the distribution of permafrost in a boreal forest watershed. The data base included both satellite-derived information and ancillary map data. Five permafrost classifications were developed from a stratified random sample of the data base and evaluated by comparison with a photo-interpreted permafrost map using contingency table analysis and soil temperatures recorded at sites within the watershed. A classification using a TM thermal band and a TM-derived vegetation map as independent variables yielded the highest mapping accuracy for all permafrost categories.

A mechanically enhanced hybrid nano-stratified barrier with a defect suppression mechanism for highly reliable flexible OLEDs.

PubMed

Jeong, Eun Gyo; Kwon, Seonil; Han, Jun Hee; Im, Hyeon-Gyun; Bae, Byeong-Soo; Choi, Kyung Cheol

2017-05-18

Understanding the mechanical behaviors of encapsulation barriers under bending stress is important when fabricating flexible organic light-emitting diodes (FOLEDs). The enhanced mechanical characteristics of a nano-stratified barrier were analyzed based on a defect suppression mechanism, and then experimentally demonstrated. Following the Griffith model, naturally-occurring cracks, which were caused by Zn etching at the interface of the nano-stratified structure, can curb the propagation of defects. Cross-section images after bending tests provided remarkable evidence to support the existence of a defect suppression mechanism. Many visible cracks were found in a single Al 2 O 3 layer, but not in the nano-stratified structure, due to the mechanism. The nano-stratified structure also enhanced the barrier's physical properties by changing the crystalline phase of ZnO. In addition, experimental results demonstrated the effect of the mechanism in various ways. The nano-stratified barrier maintained a low water vapor transmission rate after 1000 iterations of a 1 cm bending radius test. Using this mechanically enhanced hybrid nano-stratified barrier, FOLEDs were successfully encapsulated without losing mechanical or electrical performance. Finally, comparative lifetime measurements were conducted to determine reliability. After 2000 hours of constant current driving and 1000 iterations with a 1 cm bending radius, the FOLEDs retained 52.37% of their initial luminance, which is comparable to glass-lid encapsulation, with 55.96% retention. Herein, we report a mechanically enhanced encapsulation technology for FOLEDs using a nano-stratified structure with a defect suppression mechanism.

Domestic violence is associated with adult and childhood asthma prevalence in India.

PubMed

Subramanian, S V; Ackerson, Leland K; Subramanyam, Malavika A; Wright, Rosalind J

2007-06-01

Little is known on the influence of stressful psychosocial circumstances in predicting asthma. We examine the link between asthma prevalence and domestic violence (DV) in a nationally representative sample of adults and children in India. Analyses were based on the 1998-99 cross-sectional nationally representative Indian National Family Health Survey administered in 92 486 households. Individual-level prevalence of asthma was the primary outcome for this study. Exposure to DV was based on women's self-report of DV. In adjusted models, women who experienced DV either recently or in the past were at greater risk of being asthmatic [odds ratio (OR) range 1.26-1.37], compared with those who did not report any abuse. In households where women reported to have experienced DV, asthma risk was higher for all individuals in those households (OR range 1.15-1.19). The association between household DV and individual risk for asthma was also observed in gender-stratified analysis, and also in age-stratified analysis, with strong association observed in age groups of under-five, 5-14, 15-24 and 25-44 years. We find a consistent association between being exposed to, and having experienced, DV and asthma prevalence. Stress-induced mechanisms, partially captured through violence and social circumstances, may be a critical explanatory link in furthering our understanding of the social disparities in asthma.

Elliptical instability in stably stratified fluid interiors

NASA Astrophysics Data System (ADS)

Vidal, J.; Hollerbach, R.; Schaeffer, N.; Cebron, D.

2016-12-01

Self-sustained magnetic fields in celestial bodies (planets, moons, stars) are due to flows in internal electrically conducting fluids. These fluid motions are often attributed to convection, as it is the case for the Earth's liquid core and the Sun. However some past or present liquid cores may be stably stratified. Alternative mechanisms may thus be needed to understand the dynamo process in these celestial objects. Turbulent flows driven by mechanical forcings, such as tides or precession, seem very promising since they are dynamo capable. However the effect of density stratification is not clear, because it can stabilize or destabilize mechanically-driven flows.To mimic an elliptical distortion due to tidal forcing in spherical geometry (full sphere and shell), we consider a theoretical base flow with elliptical streamlines and an associated density profile. It allows to keep the numerical efficiency of spectral methods in this geometry. The flow satisfies the stress-free boundary condition. We perform the stability analysis of the base state using three-dimensional simulations to study both the linear and nonlinear regimes. Stable and unstable density profiles are considered. A complementary local stability analysis (WKB) is also performed. We show that elliptical instability can still grow upon a stable stratification. We also study the mixing of the stratification by the elliptical instability. Finally we look at the dynamo capability of these flows.

Dedicated Perioperative Hip Fracture Comanagement Programs are Cost-effective in High-volume Centers: An Economic Analysis.

PubMed

Swart, Eric; Vasudeva, Eshan; Makhni, Eric C; Macaulay, William; Bozic, Kevin J

2016-01-01

Osteoporotic hip fractures are common injuries typically occurring in patients who are older and medically frail. Studies have suggested that creation of a multidisciplinary team including orthopaedic surgeons, internal medicine physicians, social workers, and specialized physical therapists, to comanage these patients can decrease complication rates, improve time to surgery, and reduce hospital length of stay; however, they have yet to achieve widespread implementation, partly owing to concerns regarding resource requirements necessary for a comanagement program. We performed an economic analysis to determine whether implementation of a comanagement model of care for geriatric patients with osteoporotic hip fractures would be a cost-effective intervention at hospitals with moderate volume. We also calculated what annual volume of cases would be needed for a comanagement program to "break even", and finally we evaluated whether universal or risk-stratified comanagement was more cost effective. Decision analysis techniques were used to model the effect of implementing a systems-based strategy to improve inpatient perioperative care. Costs were obtained from best-available literature and included salary to support personnel and resources to expedite time to the operating room. The major economic benefit was decreased initial hospital length of stay, which was determined via literature review and meta-analysis, and a health benefit was improvement in perioperative mortality owing to expedited preoperative evaluation based on previously conducted meta-analyses. A break-even analysis was conducted to determine the annual case volume necessary for comanagement to be either (1) cost effective (improve health-related quality of life enough to be worth additional expenses) or (2) result in cost savings (actually result in decreased total expenses). This calculation assumed the scenario in which a hospital could hire only one hospitalist (and therapist and social worker) on a full-time basis. Additionally, we evaluated the scenario where the necessary staff was already employed at the hospital and could be dedicated to a comanagement service on a part-time basis, and explored the effect of triaging only patients considered high risk to a comanagement service versus comanaging all geriatric patients. Finally, probabilistic sensitivity analysis was conducted on all critical variables, with broad ranges used for values around which there was higher uncertainty. For the base case, universal comanagement was more cost effective than traditional care and risk-stratified comanagement (incremental cost effectiveness ratios of USD 41,100 per quality-adjusted life-year and USD 81,900 per quality-adjusted life-year, respectively). Comanagement was more cost effective than traditional management as long as the case volume was more than 54 patients annually (range, 41-68 patients based on sensitivity analysis) and resulted in cost savings when there were more than 318 patients annually (range, 238-397 patients). In a scenario where staff could be partially dedicated to a comanagement service, universal comanagement was more cost effective than risk-stratified comanagement (incremental cost effectiveness of USD 2300 per quality-adjusted life-year), and both comanagement programs had lower costs and better outcomes compared with traditional management. Sensitivity analysis was conducted and showed that the level of uncertainty in key variables was not high enough to change the core conclusions of the model. Implementation of a systems-based comanagement strategy using a dedicated team to improve perioperative medical care and expedite preoperative evaluation is cost effective in hospitals with moderate volume and can result in cost savings at higher-volume centers. The optimum patient population for a comanagement strategy is still being defined. Level 1, Economic and Decision Analysis.

In silico Pathway Activation Network Decomposition Analysis (iPANDA) as a method for biomarker development.

PubMed

Ozerov, Ivan V; Lezhnina, Ksenia V; Izumchenko, Evgeny; Artemov, Artem V; Medintsev, Sergey; Vanhaelen, Quentin; Aliper, Alexander; Vijg, Jan; Osipov, Andreyan N; Labat, Ivan; West, Michael D; Buzdin, Anton; Cantor, Charles R; Nikolsky, Yuri; Borisov, Nikolay; Irincheeva, Irina; Khokhlovich, Edward; Sidransky, David; Camargo, Miguel Luiz; Zhavoronkov, Alex

2016-11-16

Signalling pathway activation analysis is a powerful approach for extracting biologically relevant features from large-scale transcriptomic and proteomic data. However, modern pathway-based methods often fail to provide stable pathway signatures of a specific phenotype or reliable disease biomarkers. In the present study, we introduce the in silico Pathway Activation Network Decomposition Analysis (iPANDA) as a scalable robust method for biomarker identification using gene expression data. The iPANDA method combines precalculated gene coexpression data with gene importance factors based on the degree of differential gene expression and pathway topology decomposition for obtaining pathway activation scores. Using Microarray Analysis Quality Control (MAQC) data sets and pretreatment data on Taxol-based neoadjuvant breast cancer therapy from multiple sources, we demonstrate that iPANDA provides significant noise reduction in transcriptomic data and identifies highly robust sets of biologically relevant pathway signatures. We successfully apply iPANDA for stratifying breast cancer patients according to their sensitivity to neoadjuvant therapy.

In silico Pathway Activation Network Decomposition Analysis (iPANDA) as a method for biomarker development

PubMed Central

Ozerov, Ivan V.; Lezhnina, Ksenia V.; Izumchenko, Evgeny; Artemov, Artem V.; Medintsev, Sergey; Vanhaelen, Quentin; Aliper, Alexander; Vijg, Jan; Osipov, Andreyan N.; Labat, Ivan; West, Michael D.; Buzdin, Anton; Cantor, Charles R.; Nikolsky, Yuri; Borisov, Nikolay; Irincheeva, Irina; Khokhlovich, Edward; Sidransky, David; Camargo, Miguel Luiz; Zhavoronkov, Alex

2016-01-01

Signalling pathway activation analysis is a powerful approach for extracting biologically relevant features from large-scale transcriptomic and proteomic data. However, modern pathway-based methods often fail to provide stable pathway signatures of a specific phenotype or reliable disease biomarkers. In the present study, we introduce the in silico Pathway Activation Network Decomposition Analysis (iPANDA) as a scalable robust method for biomarker identification using gene expression data. The iPANDA method combines precalculated gene coexpression data with gene importance factors based on the degree of differential gene expression and pathway topology decomposition for obtaining pathway activation scores. Using Microarray Analysis Quality Control (MAQC) data sets and pretreatment data on Taxol-based neoadjuvant breast cancer therapy from multiple sources, we demonstrate that iPANDA provides significant noise reduction in transcriptomic data and identifies highly robust sets of biologically relevant pathway signatures. We successfully apply iPANDA for stratifying breast cancer patients according to their sensitivity to neoadjuvant therapy. PMID:27848968

Incorporating genomics into breast and prostate cancer screening: assessing the implications

PubMed Central

Chowdhury, Susmita; Dent, Tom; Pashayan, Nora; Hall, Alison; Lyratzopoulos, Georgios; Hallowell, Nina; Hall, Per; Pharoah, Paul; Burton, Hilary

2013-01-01

Individual risk prediction and stratification based on polygenic profiling may be useful in disease prevention. Risk-stratified population screening based on multiple factors including a polygenic risk profile has the potential to be more efficient than age-stratified screening. In this article, we summarize the implications of personalized screening for breast and prostate cancers. We report the opinions of multidisciplinary international experts who have explored the scientific, ethical, and logistical aspects of stratified screening. We have identified (i) the need to recognize the benefits and harms of personalized screening as compared with existing screening methods, (ii) that the use of genetic data highlights complex ethical issues including discrimination against high-risk individuals by insurers and employers and patient autonomy in relation to genetic testing of minors, (iii) the need for transparency and clear communication about risk scores, about harms and benefits, and about reasons for inclusion and exclusion from the risk-based screening process, and (iv) the need to develop new professional competences and to assess cost-effectiveness and acceptability of stratified screening programs before implementation. We conclude that health professionals and stakeholders need to consider the implications of incorporating genetic information in intervention strategies for health-care planning in the future. Genet Med 2013:15(6):423–432 PMID:23412607

Direct numerical simulation of a high Ka CH 4/air stratified premixed jet flame

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

Wang, Haiou; Hawkes, Evatt R.; Savard, Bruno

Here, direct numerical simulation (DNS) of a high Karlovitz number (Ka) CH 4/air stratified premixed jet flame was performed and used to provide insights into fundamentals of turbulent stratified premixed flames and their modelling implications. The flame exhibits significant stratification where the central jet has an equivalence ratio of 0.4, which is surrounded by a pilot flame with an equivalence ratio of 0.9. A reduced chemical mechanism for CH 4/air combustion based on GRI-Mech3.0 was used, including 268 elementary reactions and 28 transported species.

Direct numerical simulation of a high Ka CH 4/air stratified premixed jet flame

DOE PAGES

Wang, Haiou; Hawkes, Evatt R.; Savard, Bruno; ...

2018-04-24

Here, direct numerical simulation (DNS) of a high Karlovitz number (Ka) CH 4/air stratified premixed jet flame was performed and used to provide insights into fundamentals of turbulent stratified premixed flames and their modelling implications. The flame exhibits significant stratification where the central jet has an equivalence ratio of 0.4, which is surrounded by a pilot flame with an equivalence ratio of 0.9. A reduced chemical mechanism for CH 4/air combustion based on GRI-Mech3.0 was used, including 268 elementary reactions and 28 transported species.

Many multicenter trials had few events per center, requiring analysis via random-effects models or GEEs.

PubMed

Kahan, Brennan C; Harhay, Michael O

2015-12-01

Adjustment for center in multicenter trials is recommended when there are between-center differences or when randomization has been stratified by center. However, common methods of analysis (such as fixed-effects, Mantel-Haenszel, or stratified Cox models) often require a large number of patients or events per center to perform well. We reviewed 206 multicenter randomized trials published in four general medical journals to assess the average number of patients and events per center and determine whether appropriate methods of analysis were used in trials with few patients or events per center. The median number of events per center/treatment arm combination for trials using a binary or survival outcome was 3 (interquartile range, 1-10). Sixteen percent of trials had less than 1 event per center/treatment combination, 50% fewer than 3, and 63% fewer than 5. Of the trials which adjusted for center using a method of analysis which requires a large number of events per center, 6% had less than 1 event per center-treatment combination, 25% fewer than 3, and 50% fewer than 5. Methods of analysis that allow for few events per center, such as random-effects models or generalized estimating equations (GEEs), were rarely used. Many multicenter trials contain few events per center. Adjustment for center using random-effects models or GEE with model-based (non-robust) standard errors may be beneficial in these scenarios. Copyright © 2015 Elsevier Inc. All rights reserved.

Association between the BRCA2 rs144848 polymorphism and cancer susceptibility: a meta-analysis.

PubMed

Li, Qiuyan; Guan, Rongwei; Qiao, Yuandong; Liu, Chang; He, Ning; Zhang, Xuelong; Jia, Xueyuan; Sun, Haiming; Yu, Jingcui; Xu, Lidan

2017-06-13

The BRCA2 gene plays an important role in cancer carcinogenesis, and polymorphisms in this gene have been associated with cancer risk. The BRCA2 rs144848 polymorphism has been associated with several cancers, but results have been inconsistent. In the present study, a meta-analysis was performed to assess the association between the rs144848 polymorphism and cancer risk. Literature was searched from the databases of PubMed, Embase and Google Scholar before April 2016. The fixed or random effects model was used to calculate pooled odd ratios on the basis of heterogeneity. Meta-regression, sensitivity analysis, subgroup analysis and publication bias assessment were also performed using STATA 11.0 software according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2009. A total of 40 relevant studies from 30 publications including 34,911 cases and 48,329 controls were included in the final meta-analysis. Among them, 22 studies focused on breast cancer, seven on ovarian cancer, five on non-Hodgkin lymphoma, and the remaining six studies examined various other cancers. The meta-analysis results showed that there were significant associations between the rs144848 polymorphism and cancer risk in all genetic models. Stratified by cancer type, the rs144848 polymorphism was associated with non-Hodgkin lymphoma. Stratified by study design, the allele model was associated with breast cancer risk in population-based studies. The meta-analysis suggests that the BRCA2 rs144848 polymorphism may play a role in cancer risk. Further well-designed studies are warranted to confirm these results.

Efficacy of Intensive Control of Glucose in Stroke Prevention: A Meta-Analysis of Data from 59197 Participants in 9 Randomized Controlled Trials

PubMed Central

Zhang, Chi; Zhou, Yu-Hao; Xu, Chun-Li; Chi, Feng-Ling; Ju, Hai-Ning

2013-01-01

Background The efficacy of treatments that lower glucose in reducing the risk of incident stroke remains unclear. We therefore did a systematic review and meta-analysis to evaluate the efficacy of intensive control of glucose in the prevention of stroke. Methodology/Principal Findings We systematically searched Medline, EmBase, and the Cochrane Library for trials published between 1950 and June, 2012. We included randomized controlled trials that reported on the effects of intensive control of glucose on incident stroke compared with standard care. Summary estimates of relative risk (RR) reductions were calculated with a random effects model, and the analysis was further stratified by factors that could affect the treatment effects. Of 649 identified studies, we included nine relevant trials, which provided data for 59197 patients and 2037 events of stroke. Overall, intensive control of glucose as compared to standard care had no effect on incident stroke (RR, 0.96; 95%CI 0.88–1.06; P = 0.445). In the stratified analyses, a beneficial effect was seen in those trials when body mass index (BMI) more than 30 (RR, 0.86; 95%CI: 0.75–0.99; P = 0.041). No other significant differences were detected between the effect of intensive control of glucose and standard care when based on other subset factors. Conclusions/Significance Our study indicated intensive control of glucose can effectively reduce the risk of incident stroke when patients with BMI more than 30. PMID:23372729

Profiling of poorly stratified atmospheres with scanning lidar

Treesearch

C. E. Wold; V. A. Kovalev; A. P. Petkov; W. M. Hao

2012-01-01

The direct multiangle solution may allow inversion of the scanning lidar data even when the requirement of the horizontally stratified atmosphere is poorly met. The solution is based on two principles: (1) The signal measured in zenith is the core source for extracting the information about the atmospheric aerosol loading, and (2) The multiangle signals are used as...

An optimal stratified Simon two-stage design.

PubMed

Parashar, Deepak; Bowden, Jack; Starr, Colin; Wernisch, Lorenz; Mander, Adrian

2016-07-01

In Phase II oncology trials, therapies are increasingly being evaluated for their effectiveness in specific populations of interest. Such targeted trials require designs that allow for stratification based on the participants' molecular characterisation. A targeted design proposed by Jones and Holmgren (JH) Jones CL, Holmgren E: 'An adaptive Simon two-stage design for phase 2 studies of targeted therapies', Contemporary Clinical Trials 28 (2007) 654-661.determines whether a drug only has activity in a disease sub-population or in the wider disease population. Their adaptive design uses results from a single interim analysis to decide whether to enrich the study population with a subgroup or not; it is based on two parallel Simon two-stage designs. We study the JH design in detail and extend it by providing a few alternative ways to control the familywise error rate, in the weak sense as well as the strong sense. We also introduce a novel optimal design by minimising the expected sample size. Our extended design contributes to the much needed framework for conducting Phase II trials in stratified medicine. © 2016 The Authors Pharmaceutical Statistics Published by John Wiley & Sons Ltd. © 2016 The Authors Pharmaceutical Statistics Published by John Wiley & Sons Ltd.

Using impedance cardiography with postural change to stratify patients with hypertension.

PubMed

DeMarzo, Arthur P

2011-06-01

Early detection of cardiovascular disease in patients with hypertension could initiate appropriate treatment to control blood pressure and prevent the progression of cardiovascular disease. The goal of this study was to show how impedance cardiography waveform analysis with postural change can be used to detect subclinical cardiovascular disease in patients with high blood pressure. Patients with high blood pressure had impedance cardiography data obtained in two positions, standing upright and supine. In 50 adults, impedance cardiography indicated that all patients had abnormal data, with 44 (88%) having multiple abnormalities. Impedance cardiography showed 32 (64%) had ventricular dysfunction, 48 (96%) had vascular load abnormalities, 34 (68%) had hemodynamic abnormalities, 2 (4%) had hypovolemia, and 3 (6%) had hypervolemia. Hypertensive patients have diverse cardiovascular abnormalities that can be quantified by impedance cardiography. By stratifying patients with ventricular, vascular, and hemodynamic abnormalities, treatment could be customized based on the abnormal underlying mechanisms with the potential to rapidly control blood pressure, prevent progression of cardiovascular disease, and possibly reverse remodeling.

Measurements of fluid transport by controllable vertical migrations of plankton

NASA Astrophysics Data System (ADS)

Houghton, Isabel A.; Dabiri, John O.

2016-11-01

Diel vertical migration of zooplankton has been proposed to be a significant contributor to local and possibly large-scale fluid transport in the ocean. However, studies of this problem to date have been limited to order-of-magnitude estimates based on first principles and a small number of field observations. In this work, we leverage the phototactic behavior of zooplankton to stimulate controllable vertical migrations in the laboratory and to study the associated fluid transport and mixing. Building upon a previous prototype system, a laser guidance system induces vertical swimming of brine shrimp (Artemia salina) in a 2.1 meter tall, density-stratified water tank. The animal swimming speed and spacing during the controlled vertical migration is characterized with video analysis. A schlieren imaging system is utilized to visualize density perturbations to a stable stratification for quantification of fluid displacement length scales and restratification timescales. These experiments can add to our understanding of the dynamics of active particles in stratified flows. NSF and US-Israel Binational Science Foundation.

The stratifying role of job level for sickness absence and the moderating role of gender and occupational gender composition.

PubMed

Kröger, Hannes

2017-08-01

The study investigates whether sickness absence is stratified by job level - understood as the authority and autonomy a worker holds - beyond the association with education, income, and occupation. A second objective is to establish the moderating role of gender and occupational gender composition on this stratification of sickness absence. Four competing hypotheses are developed that predict different patterns of moderation. Associations between job level and sickness absence are estimated for men and women in three groups of differing occupational gender composition, using data from the German Socio-Economic Panel Study (SOEP). For the purpose of moderation analysis, this study employs a new method based on Bayesian statistics, which enables the testing of complex moderation hypotheses. The data support the hypothesis that the stratification of sickness absence by job level is strongest for occupational minorities, meaning men in female-dominated and women in male-dominated occupations. Copyright © 2017 Elsevier Ltd. All rights reserved.

Stratified prevention: opportunities and limitations. Report on the 1st interdisciplinary cardiovascular workshop in Augsburg.

PubMed

Kirchhof, Gregor; Lindner, Josef Franz; Achenbach, Stephan; Berger, Klaus; Blankenberg, Stefan; Fangerau, Heiner; Gimpel, Henner; Gassner, Ulrich M; Kersten, Jens; Magnus, Dorothea; Rebscher, Herbert; Schunkert, Heribert; Rixen, Stephan; Kirchhof, Paulus

2018-03-01

Sufficient exercise and sleep, a balanced diet, moderate alcohol consumption and a good approach to handle stress have been known as lifestyles that protect health and longevity since the Middle Age. This traditional prevention quintet, turned into a sextet by smoking cessation, has been the basis of the "preventive personality" that formed in the twentieth century. Recent analyses of big data sets including genomic and physiological measurements have unleashed novel opportunities to estimate individual health risks with unprecedented accuracy, allowing to target preventive interventions to persons at high risk and at the same time to spare those in whom preventive measures may not be needed or even be harmful. To fully grasp these opportunities for modern preventive medicine, the established healthy life styles require supplementation by stratified prevention. The opportunities of these developments for life and health contrast with justified concerns: A "surveillance society", able to predict individual behaviour based on big data, threatens individual freedom and jeopardises equality. Social insurance law and the new German Disease Prevention Act (Präventionsgesetz) rightly stress the need for research to underpin stratified prevention which is accessible to all, ethical, effective, and evidence based. An ethical and acceptable development of stratified prevention needs to start with autonomous individuals who control and understand all information pertaining to their health. This creates a mandate for lifelong health education, enabled in an individualised form by digital technology. Stratified prevention furthermore requires the evidence-based development of a new taxonomy of cardiovascular diseases that reflects disease mechanisms. Such interdisciplinary research needs broad support from society and a better use of biosamples and data sets within an updated research governance framework.

Race/ethnicity and income in relation to the home food environment in US youth aged 6 to 19 years.

PubMed

Masters, Melissa A; Stanek Krogstrand, Kaye L; Eskridge, Kent M; Albrecht, Julie A

2014-10-01

The home food environment is complex and has the potential to influence dietary habit development in young people. Several factors may influence the home food environment, including income and race/ethnicity. To examine the relationship of income and race/ethnicity with three home food environment factors (ie, food availability frequency, family meal patterns [frequency of family and home cooked meals], and family food expenditures). A cross-sectional analysis of the National Health and Nutrition Examination Survey (NHANES). A total of 5,096 youth aged 6 to 19 years from a nationally representative sample of US individuals participating in NHANES 2007-10. Prevalence of food availability frequency was assessed for the entire sample, race/ethnicity, poverty income ratio (PIR), and race/ethnicity stratified by PIR. Mean values of family meal patterns and food expenditures were calculated based on race/ethnicity, PIR, and race/ethnicity stratified by PIR using analysis of variance and least squares means. Tests of main effects were used to assess differences in food availability prevalence and mean values of family meal patterns and food expenditures. Non-Hispanic whites had the highest prevalence of salty snacks (51.1%±1.5%) and fat-free/low-fat milk (39.2%±1.7%) always available. High-income homes had the highest prevalence of fruits (75.4%±2.4%) and fat-free/low-fat milk (38.4%±2.1%) always available. Differences were found for prevalence of food availability when race/ethnicity was stratified by PIR. Non-Hispanic blacks had the lowest prevalence of fat-free/low-fat milk always available across PIR groups. Differences in mean levels of family meal patterns and food expenditures were found for race/ethnicity, PIR, and race/ethnicity stratified by PIR. Race/ethnicity and PIR appear to influence food availability, family meal patterns, and family food expenditures in homes of youth. Knowledge of factors that influence the home food environment could assist in developing effective strategies to improve food environments for young people. Copyright © 2014 Academy of Nutrition and Dietetics. Published by Elsevier Inc. All rights reserved.

Interleukin-10 -1082 promoter polymorphism associated with gastric cancer among Asians.

PubMed

Zhou, Yong; Li, Ni; Zhuang, Wen; Liu, Guan-Jian; Wu, Tai-Xiang; Yao, Xun; Du, Liang; Wei, Mao-Ling; Wu, Xiao-Ting

2008-11-01

Studies investigating the association between interleukin-10 (IL-10) -1082 promoter polymorphism and gastric cancer risk report conflicting results. The objective of this study was to quantitatively summarise the evidence for such a relationship. Two investigators independently searched the Medline and Embase databases. This meta-analysis included 13 case-control studies, which included 2227 gastric cancer cases and 3538 controls. The combined results based on all studies showed that there was no significant difference in genotype distribution [AA odds ratio (OR)=0.92, 95% confidence interval (CI)=0.73, 1.14; AG (OR=1.09, 95% CI=0.87, 1.36); GG (OR=1.03, 95% CI=0.85, 1.25)] between gastric cancer and noncancer patients. When stratifying for race, results were similar except that patients with gastric cancer had a significantly lower frequency of AA (OR=0.71, 95% CI=0.52, 0.97) and higher frequency AG (OR=1.53, 95% CI=1.15, 2.03) than noncancer patients among Asians. When stratifying by the location of gastric cancer, we found that patients with cardia gastric cancer had a significantly lower frequency of AA (OR=0.53, 95% CI=0.34, 0.83) and higher frequency AG (OR=1.50, 95% CI=1.06, 2.11) than those with noncardia gastric cancer among Caucasians. When stratifying by the Lauren's classification of gastric cancer, we observed no statistically significant differences in genotype distribution. This meta-analysis suggests that the IL-10 -1082 promoter polymorphism may be associated with gastric cancer among Asians, and that differences in genotype distribution may be associated with the location of gastric cancer.

Coffee consumption modifies risk of estrogen-receptor negative breast cancer

PubMed Central

2011-01-01

Introduction Breast cancer is a complex disease and may be sub-divided into hormone-responsive (estrogen receptor (ER) positive) and non-hormone-responsive subtypes (ER-negative). Some evidence suggests that heterogeneity exists in the associations between coffee consumption and breast cancer risk, according to different estrogen receptor subtypes. We assessed the association between coffee consumption and postmenopausal breast cancer risk in a large population-based study (2,818 cases and 3,111 controls), overall, and stratified by ER tumour subtypes. Methods Odds ratios (OR) and corresponding 95% confidence intervals (CI) were estimated using the multivariate logistic regression models fitted to examine breast cancer risk in a stratified case-control analysis. Heterogeneity among ER subtypes was evaluated in a case-only analysis, by fitting binary logistic regression models, treating ER status as a dependent variable, with coffee consumption included as a covariate. Results In the Swedish study, coffee consumption was associated with a modest decrease in overall breast cancer risk in the age-adjusted model (OR> 5 cups/day compared to OR≤ 1 cup/day: 0.80, 95% CI: 0.64, 0.99, P trend = 0.028). In the stratified case-control analyses, a significant reduction in the risk of ER-negative breast cancer was observed in heavy coffee drinkers (OR> 5 cups/day compared to OR≤ 1 cup/day : 0.43, 95% CI: 0.25, 0.72, P trend = 0.0003) in a multivariate-adjusted model. The breast cancer risk reduction associated with higher coffee consumption was significantly higher for ER-negative compared to ER-positive tumours (P heterogeneity (age-adjusted) = 0.004). Conclusions A high daily intake of coffee was found to be associated with a statistically significant decrease in ER-negative breast cancer among postmenopausal women. PMID:21569535

Variation in Outcomes for Risk-Stratified Pediatric Cardiac Surgical Operations: An Analysis of the STS Congenital Heart Surgery Database

PubMed Central

Jacobs, Jeffrey Phillip; O'Brien, Sean M.; Pasquali, Sara K.; Jacobs, Marshall Lewis; Lacour-Gayet, François G.; Tchervenkov, Christo I.; Austin III, Erle H.; Pizarro, Christian; Pourmoghadam, Kamal K.; Scholl, Frank G.; Welke, Karl F.; Gaynor, J. William; Clarke, David R.; Mayer, John E.; Mavroudis, Constantine

2013-01-01

Background. We evaluated outcomes for groups of risk-stratified operations in The Society of Thoracic Surgeons Congenital Heart Surgery Database to provide contemporary benchmarks and examine variation between centers. Methods. Patients undergoing surgery from 2005 to 2009 were included. Centers with more than 10% missing data were excluded. Discharge mortality and postoperative length of stay (PLOS) among patients discharged alive were calculated for groups of risk-stratified operations using the five Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery Congenital Heart Surgery mortality categories (STAT Mortality Categories). Power for analyzing between-center differences in outcome was determined for each STAT Mortality Category. Variation was evaluated using funnel plots and Bayesian hierarchical modeling. Results. In this analysis of risk-stratified operations, 58,506 index operations at 73 centers were included. Overall discharge mortality (interquartile range among programs with more than 10 cases) was as follows: STAT Category 1 = 0.55% (0% to 1.0%), STAT Category 2 = 1.7% (1.0% to 2.2%), STAT Category 3 = 2.6% (1.1% to 4.4%), STAT Category 4 = 8.0% (6.3% to 11.1%), and STAT Category 5 = 18.4% (13.9% to 27.9%). Funnel plots with 95% prediction limits revealed the number of centers characterized as outliers by STAT Mortality Categories was as follows: Category 1 = 3 (4.1%), Category 2 = 1 (1.4%), Category 3 = 7 (9.7%), Category 4 = 13 (17.8%), and Category 5 = 13 (18.6%). Between-center variation in PLOS was analyzed for all STAT Categories and was greatest for STAT Category 5 operations. Conclusions. This analysis documents contemporary benchmarks for risk-stratified pediatric cardiac surgical operations grouped by STAT Mortality Categories and the range of outcomes among centers. Variation was greatest for the more complex operations. These data may aid in the design and planning of quality assessment and quality improvement initiatives. PMID:22704799

Variation in outcomes for risk-stratified pediatric cardiac surgical operations: an analysis of the STS Congenital Heart Surgery Database.

PubMed

Jacobs, Jeffrey Phillip; O'Brien, Sean M; Pasquali, Sara K; Jacobs, Marshall Lewis; Lacour-Gayet, François G; Tchervenkov, Christo I; Austin, Erle H; Pizarro, Christian; Pourmoghadam, Kamal K; Scholl, Frank G; Welke, Karl F; Gaynor, J William; Clarke, David R; Mayer, John E; Mavroudis, Constantine

2012-08-01

We evaluated outcomes for groups of risk-stratified operations in The Society of Thoracic Surgeons Congenital Heart Surgery Database to provide contemporary benchmarks and examine variation between centers. Patients undergoing surgery from 2005 to 2009 were included. Centers with more than 10% missing data were excluded. Discharge mortality and postoperative length of stay (PLOS) among patients discharged alive were calculated for groups of risk-stratified operations using the five Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery Congenital Heart Surgery mortality categories (STAT Mortality Categories). Power for analyzing between-center differences in outcome was determined for each STAT Mortality Category. Variation was evaluated using funnel plots and Bayesian hierarchical modeling. In this analysis of risk-stratified operations, 58,506 index operations at 73 centers were included. Overall discharge mortality (interquartile range among programs with more than 10 cases) was as follows: STAT Category 1=0.55% (0% to 1.0%), STAT Category 2=1.7% (1.0% to 2.2%), STAT Category 3=2.6% (1.1% to 4.4%), STAT Category 4=8.0% (6.3% to 11.1%), and STAT Category 5=18.4% (13.9% to 27.9%). Funnel plots with 95% prediction limits revealed the number of centers characterized as outliers by STAT Mortality Categories was as follows: Category 1=3 (4.1%), Category 2=1 (1.4%), Category 3=7 (9.7%), Category 4=13 (17.8%), and Category 5=13 (18.6%). Between-center variation in PLOS was analyzed for all STAT Categories and was greatest for STAT Category 5 operations. This analysis documents contemporary benchmarks for risk-stratified pediatric cardiac surgical operations grouped by STAT Mortality Categories and the range of outcomes among centers. Variation was greatest for the more complex operations. These data may aid in the design and planning of quality assessment and quality improvement initiatives. Copyright © 2012 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Assessing the impact of natural policy experiments on socioeconomic inequalities in health: how to apply commonly used quantitative analytical methods?

PubMed

Hu, Yannan; van Lenthe, Frank J; Hoffmann, Rasmus; van Hedel, Karen; Mackenbach, Johan P

2017-04-20

The scientific evidence-base for policies to tackle health inequalities is limited. Natural policy experiments (NPE) have drawn increasing attention as a means to evaluating the effects of policies on health. Several analytical methods can be used to evaluate the outcomes of NPEs in terms of average population health, but it is unclear whether they can also be used to assess the outcomes of NPEs in terms of health inequalities. The aim of this study therefore was to assess whether, and to demonstrate how, a number of commonly used analytical methods for the evaluation of NPEs can be applied to quantify the effect of policies on health inequalities. We identified seven quantitative analytical methods for the evaluation of NPEs: regression adjustment, propensity score matching, difference-in-differences analysis, fixed effects analysis, instrumental variable analysis, regression discontinuity and interrupted time-series. We assessed whether these methods can be used to quantify the effect of policies on the magnitude of health inequalities either by conducting a stratified analysis or by including an interaction term, and illustrated both approaches in a fictitious numerical example. All seven methods can be used to quantify the equity impact of policies on absolute and relative inequalities in health by conducting an analysis stratified by socioeconomic position, and all but one (propensity score matching) can be used to quantify equity impacts by inclusion of an interaction term between socioeconomic position and policy exposure. Methods commonly used in economics and econometrics for the evaluation of NPEs can also be applied to assess the equity impact of policies, and our illustrations provide guidance on how to do this appropriately. The low external validity of results from instrumental variable analysis and regression discontinuity makes these methods less desirable for assessing policy effects on population-level health inequalities. Increased use of the methods in social epidemiology will help to build an evidence base to support policy making in the area of health inequalities.

Obstetric mode of delivery and attention-deficit/hyperactivity disorder: a sibling-matched study.

PubMed

Curran, Eileen A; Khashan, Ali S; Dalman, Christina; Kenny, Louise C; Cryan, John F; Dinan, Timothy G; Kearney, Patricia M

2016-04-01

It has been suggested that birth by caesarean section (CS) may affect psychological development through changes in microbiota or stress response. We assessed the impact of mode of delivery, specifically CS, on the development of attention-deficit/hyperactivity disorder (ADHD), using a large, population-based cohort. The study cohort consisted of all singleton live births in Sweden from 1990 to 2008 using data from Swedish national registers. Mode of delivery included: unassisted vaginal delivery(VD), assisted VD, elective CS or emergency CS. ADHD was determined using International Classification of Diseases version 10 (F90 or F98.8), or prescription for ADHD medication. We used Cox regression to assess the association between birth by CS and ADHD in the total study population, adjusting for perinatal and sociodemographic factors, then stratified Cox regression analysis on maternal identification number to assess the association among siblings. Our cohort consisted of 1 722 548 children, and among these 47 778 cases of ADHD. The hazard ratio (HR) of the association between elective CS, compared with unassisted VD, and ADHD was 1.15 [95% confidence interval (CI): 1.11-1.20] in the cohort, and 1.05 (95% CI: 0.93-1.18) in the stratified analysis. The HR of the association between emergency CS and ADHD was 1.16 (95% CI: 1.12-1.20])in the cohort and 1.13 (95% CI: 1.01-1.26) in the stratified analysis. Birth by CS is associated with a small increased risk of ADHD. However among siblings the association only remained for emergency CS. If this were a causal effect by CS, the association would be expected to persist for both types of CS, suggesting the observed association is due to confounding. © The Author 2016; all rights reserved. Published by Oxford University Press on behalf of the International Epidemiological Association.

Generalization and fine mapping of European ancestry-based central adiposity variants in African ancestry populations

PubMed Central

Yoneyama, Sachiko; Yao, Jie; Guo, Xiuqing; Fernandez-Rhodes, Lindsay; Lim, Unhee; Boston, Jonathan; Buzková, Petra; Carlson, Christopher S.; Cheng, Iona; Cochran, Barbara; Cooper, Richard; Ehret, Georg; Fornage, Myriam; Gong, Jian; Gross, Myron; Gu, C. Charles; Haessler, Jeff; Haiman, Christopher A.; Henderson, Brian; Hindorff, Lucia A.; Houston, Denise; Irvin, Marguerite R.; Jackson, Rebecca; Kuller, Lew; Leppert, Mark; Lewis, Cora E.; Li, Rongling; Le Marchand, Loic; Matise, Tara C.; Nguyen, Khanh-Dung H.; Chakravarti, Aravinda; Pankow, James S.; Pankratz, Nathan; Pooler, Loreall; Ritchie, Marylyn D.; Bien, Stephanie A.; Wassel, Christina L.; Chen, Yii-Der I.; Taylor, Kent D.; Allison, Matthew; Rotter, Jerome I.; Schreiner, Pamela J.; Schumacher, Fredrick; Wilkens, Lynne; Boerwinkle, Eric; Kooperberg, Charles; Peters, Ulrike; Buyske, Steven; Graff, Mariaelisa; North, Kari E.

2016-01-01

Background/Objectives Central adiposity measures such as waist circumference (WC) and waist-to-hip ratio (WHR) are associated with cardiometabolic disorders independently of BMI and are gaining clinically utility. Several studies report genetic variants associated with central adiposity, but most utilize only European ancestry populations. Understanding whether the genetic associations discovered among mainly European descendants are shared with African ancestry populations will help elucidate the biological underpinnings of abdominal fat deposition. Subjects/Methods To identify the underlying functional genetic determinants of body fat distribution, we conducted an array-wide association meta-analysis among persons of African ancestry across seven studies/consortia participating in the Population Architecture using Genomics and Epidemiology (PAGE) consortium. We used the Metabochip array, designed for fine mapping cardiovascular associated loci, to explore novel array-wide associations with WC and WHR among 15 945 African descendants using all and sex-stratified groups. We further interrogated 17 known WHR regions for African ancestry-specific variants. Results Of the 17 WHR loci, eight SNPs located in four loci were replicated in the sex-combined or sex-stratified meta-analyses. Two of these eight independently associated with WHR after conditioning on the known variant in European descendants (rs12096179 in TBX15-WARS2 and rs2059092 in ADAMTS9). In the fine mapping assessment, the putative functional region was reduced across all four loci but to varying degrees (average 40% drop in number of putative SNPs and 20% drop in genomic region). Similar to previous studies, the significant SNPs in the female stratified analysis were stronger than the significant SNPs from the sex-combined analysis. No novel associations were detected in the array-wide analyses. Conclusions Of 17 previously identified loci, four loci replicated in the African ancestry populations of this study. Utilizing different linkage disequilibrium patterns observed between European and African ancestries, we narrowed the suggestive region containing causative variants for all four loci. PMID:27867202

Post-stratified estimation of forest area and growing stock volume using lidar-based stratifications

Treesearch

Ronald E. McRoberts; Terje Gobakken; Erik Næsset

2012-01-01

National forest inventories report estimates of parameters related to forest area and growing stock volume for geographic areas ranging in size from municipalities to entire countries. Landsat imagery has been shown to be a source of auxiliary information that can be used with stratified estimation to increase the precision of estimates, although the increase is...

Vortex ring motions in stratified media

NASA Astrophysics Data System (ADS)

Auvity, Bruno; Koulal, Mokrane; Dupont, Pascal; Peerhossaini, Hassan

2003-11-01

The behavior of vortex rings generated in a stably stratified media has received only weak treatment in the literature. This configuration is believed to shed light on the basic phenomena involved in the collapse of wake in stratified fluid. The present study focused on experimental observations of the formation, the advection and the collapse of horizontal vortex rings in stratified media. Stable continuous vertical stratification was produced in a tank using the well-known two-tanks method. The generation of vortex ring was realized moving a piston through a tube. The maximum piston stroke achievable was seven tube diameters. The problem is mainly characterized by two parameters : the initial Reynolds number and the initial Froude number of the vortex ring. Both these numbers were varied in the study. The Reynolds number based on the tube diameter and piston velocity was in the range 1,500 - 5,500 and the Froude number based on the same parameters in the range 1.4 - 4.7. Dye visualizations were performed from the top and the side of the tank showing the vortex ring may develop an important asymmetry. Different processes to the complete collapse of the vortex ring were identified.

Node Redeployment Algorithm Based on Stratified Connected Tree for Underwater Sensor Networks

PubMed Central

Liu, Jun; Jiang, Peng; Wu, Feng; Yu, Shanen; Song, Chunyue

2016-01-01

During the underwater sensor networks (UWSNs) operation, node drift with water environment causes network topology changes. Periodic node location examination and adjustment are needed to maintain good network monitoring quality as long as possible. In this paper, a node redeployment algorithm based on stratified connected tree for UWSNs is proposed. At every network adjustment moment, self-examination and adjustment on node locations are performed firstly. If a node is outside the monitored space, it returns to the last location recorded in its memory along straight line. Later, the network topology is stratified into a connected tree that takes the sink node as the root node by broadcasting ready information level by level, which can improve the network connectivity rate. Finally, with synthetically considering network coverage and connectivity rates, and node movement distance, the sink node performs centralized optimization on locations of leaf nodes in the stratified connected tree. Simulation results show that the proposed redeployment algorithm can not only keep the number of nodes in the monitored space as much as possible and maintain good network coverage and connectivity rates during network operation, but also reduce node movement distance during node redeployment and prolong the network lifetime. PMID:28029124

Single-particle dispersion in stably stratified turbulence

NASA Astrophysics Data System (ADS)

Sujovolsky, N. E.; Mininni, P. D.; Rast, M. P.

2018-03-01

We present models for single-particle dispersion in vertical and horizontal directions of stably stratified flows. The model in the vertical direction is based on the observed Lagrangian spectrum of the vertical velocity, while the model in the horizontal direction is a combination of a continuous-time eddy-constrained random walk process with a contribution to transport from horizontal winds. Transport at times larger than the Lagrangian turnover time is not universal and dependent on these winds. The models yield results in good agreement with direct numerical simulations of stratified turbulence, for which single-particle dispersion differs from the well-studied case of homogeneous and isotropic turbulence.

New Correlation Methods of Evaporation Heat Transfer in Horizontal Microfine Tubes

NASA Astrophysics Data System (ADS)

Makishi, Osamu; Honda, Hiroshi

A stratified flow model and an annular flow model of evaporation heat transfer in horizontal microfin tubes have been proposed. In the stratified flow model, the contributions of thin film evaporation and nucleate boiling in the groove above a stratified liquid were predicted by a previously reported numerical analysis and a newly developed correlation, respectively. The contributions of nucleate boiling and forced convection in the stratified liquid region were predicted by the new correlation and the Carnavos equation, respectively. In the annular flow model, the contributions of nucleate boiling and forced convection were predicted by the new correlation and the Carnavos equation in which the equivalent Reynolds number was introduced, respectively. A flow pattern transition criterion proposed by Kattan et al. was incorporated to predict the circumferential average heat transfer coefficient in the intermediate region by use of the two models. The predictions of the heat transfer coefficient compared well with available experimental data for ten tubes and four refrigerants.

Unsteady Shear Disturbances Within a Two Dimensional Stratified Flow

NASA Technical Reports Server (NTRS)

Yokota, Jeffrey W.

1992-01-01

The origin and evolution of shear disturbances within a stratified, inviscid, incompressible flow are investigated numerically by a Clebsch/Weber decomposition based scheme. In contrast to homogeneous flows, within which vorticity can be redistributed but not generated, the presence of a density stratification can render an otherwise irrotational flow vortical. In this work, a kinematic decomposition of the unsteady Euler equations separates the unsteady velocity field into rotational and irrotational components. The subsequent evolution of these components is used to study the influence various velocity disturbances have on both stratified and homogeneous flows. In particular, the flow within a two-dimensional channel is used to investigate the evolution of rotational disturbances, generated or convected, downstream from an unsteady inflow condition. Contrasting simulations of both stratified and homogeneous flows are used to distinguish between redistributed inflow vorticity and that which is generated by a density stratification.

A Meta-Analysis to Determine the Impact of Restaurant Menu Labeling on Calories and Nutrients (Ordered or Consumed) in U.S. Adults

PubMed Central

Cantu-Jungles, Thaisa M.; McCormack, Lacey A.; Slaven, James E.; Slebodnik, Maribeth

2017-01-01

A systematic review and meta-analysis determined the effect of restaurant menu labeling on calories and nutrients chosen in laboratory and away-from-home settings in U.S. adults. Cochrane-based criteria adherent, peer-reviewed study designs conducted and published in the English language from 1950 to 2014 were collected in 2015, analyzed in 2016, and used to evaluate the effect of nutrition labeling on calories and nutrients ordered or consumed. Before and after menu labeling outcomes were used to determine weighted mean differences in calories, saturated fat, total fat, carbohydrate, and sodium ordered/consumed which were pooled across studies using random effects modeling. Stratified analysis for laboratory and away-from-home settings were also completed. Menu labeling resulted in no significant change in reported calories ordered/consumed in studies with full criteria adherence, nor the 14 studies analyzed with ≤1 unmet criteria, nor for change in total ordered carbohydrate, fat, and saturated fat (three studies) or ordered or consumed sodium (four studies). A significant reduction of 115.2 calories ordered/consumed in laboratory settings was determined when analyses were stratified by study setting. Menu labeling away-from-home did not result in change in quantity or quality, specifically for carbohydrates, total fat, saturated fat, or sodium, of calories consumed among U.S. adults. PMID:28973989

Likelihood analysis of spatial capture-recapture models for stratified or class structured populations

USGS Publications Warehouse

Royle, J. Andrew; Sutherland, Christopher S.; Fuller, Angela K.; Sun, Catherine C.

2015-01-01

We develop a likelihood analysis framework for fitting spatial capture-recapture (SCR) models to data collected on class structured or stratified populations. Our interest is motivated by the necessity of accommodating the problem of missing observations of individual class membership. This is particularly problematic in SCR data arising from DNA analysis of scat, hair or other material, which frequently yields individual identity but fails to identify the sex. Moreover, this can represent a large fraction of the data and, given the typically small sample sizes of many capture-recapture studies based on DNA information, utilization of the data with missing sex information is necessary. We develop the class structured likelihood for the case of missing covariate values, and then we address the scaling of the likelihood so that models with and without class structured parameters can be formally compared regardless of missing values. We apply our class structured model to black bear data collected in New York in which sex could be determined for only 62 of 169 uniquely identified individuals. The models containing sex-specificity of both the intercept of the SCR encounter probability model and the distance coefficient, and including a behavioral response are strongly favored by log-likelihood. Estimated population sex ratio is strongly influenced by sex structure in model parameters illustrating the importance of rigorous modeling of sex differences in capture-recapture models.

A Meta-Analysis to Determine the Impact of Restaurant Menu Labeling on Calories and Nutrients (Ordered or Consumed) in U.S. Adults.

PubMed

Cantu-Jungles, Thaisa M; McCormack, Lacey A; Slaven, James E; Slebodnik, Maribeth; Eicher-Miller, Heather A

2017-09-30

A systematic review and meta-analysis determined the effect of restaurant menu labeling on calories and nutrients chosen in laboratory and away-from-home settings in U.S. adults. Cochrane-based criteria adherent, peer-reviewed study designs conducted and published in the English language from 1950 to 2014 were collected in 2015, analyzed in 2016, and used to evaluate the effect of nutrition labeling on calories and nutrients ordered or consumed. Before and after menu labeling outcomes were used to determine weighted mean differences in calories, saturated fat, total fat, carbohydrate, and sodium ordered/consumed which were pooled across studies using random effects modeling. Stratified analysis for laboratory and away-from-home settings were also completed. Menu labeling resulted in no significant change in reported calories ordered/consumed in studies with full criteria adherence, nor the 14 studies analyzed with ≤1 unmet criteria, nor for change in total ordered carbohydrate, fat, and saturated fat (three studies) or ordered or consumed sodium (four studies). A significant reduction of 115.2 calories ordered/consumed in laboratory settings was determined when analyses were stratified by study setting. Menu labeling away-from-home did not result in change in quantity or quality, specifically for carbohydrates, total fat, saturated fat, or sodium, of calories consumed among U.S. adults.

Assessment of the association between overweight/obesity and traumatic dental injury among Brazilian schoolchildren.

PubMed

Martins, Veruska M; Sousa, Raulison V; Rocha, Eveline S; Leite, Rafaella B; Gomes, Monalisa C; Granville-Garcia, Ana F

2014-01-01

The aim of this study was to evaluate the association between overweight/obesity and the occurrence of traumatic dental injury among schoolchildren aged 7 to 14 years. A cross-sectional study was carried out involving 590 students at public schools in the city of Campina Grande, Brazil. The classification proposed by O'Brien (1994) was used for the diagnosis of traumatic dental injury. Overweight/obesity was determined based on the body mass index. Clinical examinations were performed by two examiners who had undergone a calibration exercise (Kappa statistics of 0.87 and 0.90 for intra-examiner and inter-examiner, respectively). Data analysis involved the chi-square test and Fisher's exact test with a 5% level of significance. Traumatic dental injury was less prevalent among the schoolchildren with overweight/obesity than those without this condition (8.7% and 13.3%, respectively). When the sample was stratified by gender and age, traumatic dental injury was also more prevalent among schoolchildren without overweight/obesity. When the sample was stratified based on ethnicity, prevalence rates were similar between those with and without overweight/obesity. In the overall sample, no significant association was found between overweight/obesity and traumatic dental injury (p = 0.253). Overweight/obesity among schoolchildren aged 7 to 14 years was not associated with traumatic dental injury in this study. The analysis of physical activity may be important to gain a better understanding of this finding.

The Impact of Race in Male Breast Cancer Treatment and Outcome in the United States: A Population-Based Analysis of 4,279 Patients

PubMed Central

Shin, Jacob Y.; Kachnic, Lisa A.; Hirsch, Ariel E.

2014-01-01

The purpose of this study is to compare the racial differences in treatment and overall survival (OS) of male breast cancer (MBC) patients. Data were extracted from the NCI SEER database that included population-based registries from 1988 to 2010 and analyzed using SPSS 20.0. 4,279 MBC patients were identified. 3,266 (76.3%) patients were White, 552 (12.9%) Black, 246 (5.7%) Hispanic, and 215 (5.0%) Asian. Black patients were more likely to be diagnosed at younger age (P < 0.001), have advanced stage disease (P = 0.001), and be unmarried (P < 0.001) and less likely to undergo lymph node dissection (P = 0.006). When stratified by stage, there was no difference in receipt of primary treatment by race. The 5-year OS for White, Black, Hispanic, and Asian races was 73.8%, 66.3%, 74.0%, and 85.3% (P < 0.001). This significant worse 5-year OS for Blacks persisted regardless of age, stage II or III disease, and grade 2 or 3 disease. On multivariate analysis, Black race was a significant independent prognostic factor for worse OS. Blacks were less likely to receive lymph node dissection of which patients may derive benefit, though we did not observe receipt of primary treatment, after stratifying for disease stage, to be an underlying factor contributing to racial outcome differences. PMID:25349739

Coffee consumption is not associated with ovarian cancer risk: a dose-response meta-analysis of prospective cohort studies.

PubMed

Berretta, Massimiliano; Micek, Agnieszka; Lafranconi, Alessandra; Rossetti, Sabrina; Di Francia, Raffaele; De Paoli, Paolo; Rossi, Paola; Facchini, Gaetano

2018-04-17

Coffee consumption has been associated with numerous cancers, but evidence on ovarian cancer risk is controversial. Therefore, we performed a meta-analysis on prospective cohort studies in order to review the evidence on coffee consumption and risk of ovarian cancer. Studies were identified through searching the PubMed and MEDLINE databases up to March 2017. Risk estimates were retrieved from the studies, and dose-response analysis was modelled by using restricted cubic splines. Additionally, a stratified analysis by menopausal status was performed. A total of 8 studies were eligible for the dose-response meta-analysis. Studies included in the analysis comprised 787,076 participants and 3,541 ovarian cancer cases. The results showed that coffee intake was not associated with ovarian cancer risk (RR = 1.06, 95% CI: 0.89, 1.26). Stratified and subgroup analysis showed consisted results. This comprehensive meta-analysis did not find evidence of an association between the consumption of coffee and risk of ovarian cancer.

Development of Improved Algorithms and Multiscale Modeling Capability with SUNTANS

DTIC Science & Technology

2013-09-30

solves the Navier-Stokes equations under the Boussinesq approximation (Fringer et al.,2006). The formulation is based on the method outlined by...stratified systems . Figure 4 shows a nonhydrostatic isopycnal simulation of oscillatory flow in a continuously stratified fluid over a Gaussian sill. This...Modeling the Earth System , Boulder (invited). Sankaranarayanan, S., and Fringer, O. B., 2013, "Dynamics of barotropic low-frequency fluctuations in

Combined assessment of myocardial damage and electrical disturbance in chronic heart failure

PubMed Central

Kadowaki, Shinpei; Watanabe, Tetsu; Otaki, Yoichiro; Narumi, Taro; Honda, Yuki; Takahashi, Hiroki; Arimoto, Takanori; Shishido, Tetsuro; Miyamoto, Takuya; Kubota, Isao

2017-01-01

AIM To investigate feasibility of combined assessment of biochemical and electrophysiological myocardial impairment markers risk-stratifying patients with chronic heart failure (CHF). METHODS Serum levels of heart-type fatty acid binding protein (H-FABP) as a marker of ongoing myocardial damage and QRS duration on electrocardiogram were measured at admission in 322 consecutive patients with CHF. A prolonged QRS duration was defined as 120 ms or longer. The cut-off value for H-FABP level (4.5 ng/mL) was determined from a previous study. Patients were prospectively followed during a median follow up period of 534 d. The primary endpoint was cardiac deaths and rehospitalization for worsening CHF. RESULTS There were 117 primary events, including 27 cardiac deaths and 90 rehospitalizations. Patients were stratified into four groups according to H-FABP level and QRS duration (≥ 120 ms). Multivariate analysis demonstrated that high H-FABP levels [hazard ratio (HR) = 1.745, P = 0.021] and QRS prolongation (HR 1.612, P = 0.0258) were independent predictors of cardiac events. Kaplan-Meier analysis demonstrated that the combination of high H-FABP levels and QRS prolongation could be used to reliably stratify patients at high risk for cardiac events (log rank test P < 0.0001). CONCLUSION Combined assessment of myocardial damage and electrical disturbance can be used to risk-stratify patients with CHF. PMID:28603594

Background stratified Poisson regression analysis of cohort data.

PubMed

Richardson, David B; Langholz, Bryan

2012-03-01

Background stratified Poisson regression is an approach that has been used in the analysis of data derived from a variety of epidemiologically important studies of radiation-exposed populations, including uranium miners, nuclear industry workers, and atomic bomb survivors. We describe a novel approach to fit Poisson regression models that adjust for a set of covariates through background stratification while directly estimating the radiation-disease association of primary interest. The approach makes use of an expression for the Poisson likelihood that treats the coefficients for stratum-specific indicator variables as 'nuisance' variables and avoids the need to explicitly estimate the coefficients for these stratum-specific parameters. Log-linear models, as well as other general relative rate models, are accommodated. This approach is illustrated using data from the Life Span Study of Japanese atomic bomb survivors and data from a study of underground uranium miners. The point estimate and confidence interval obtained from this 'conditional' regression approach are identical to the values obtained using unconditional Poisson regression with model terms for each background stratum. Moreover, it is shown that the proposed approach allows estimation of background stratified Poisson regression models of non-standard form, such as models that parameterize latency effects, as well as regression models in which the number of strata is large, thereby overcoming the limitations of previously available statistical software for fitting background stratified Poisson regression models.

Quasi-Likelihood Techniques in a Logistic Regression Equation for Identifying Simulium damnosum s.l. Larval Habitats Intra-cluster Covariates in Togo.

PubMed

Jacob, Benjamin G; Novak, Robert J; Toe, Laurent; Sanfo, Moussa S; Afriyie, Abena N; Ibrahim, Mohammed A; Griffith, Daniel A; Unnasch, Thomas R

2012-01-01

The standard methods for regression analyses of clustered riverine larval habitat data of Simulium damnosum s.l. a major black-fly vector of Onchoceriasis, postulate models relating observational ecological-sampled parameter estimators to prolific habitats without accounting for residual intra-cluster error correlation effects. Generally, this correlation comes from two sources: (1) the design of the random effects and their assumed covariance from the multiple levels within the regression model; and, (2) the correlation structure of the residuals. Unfortunately, inconspicuous errors in residual intra-cluster correlation estimates can overstate precision in forecasted S.damnosum s.l. riverine larval habitat explanatory attributes regardless how they are treated (e.g., independent, autoregressive, Toeplitz, etc). In this research, the geographical locations for multiple riverine-based S. damnosum s.l. larval ecosystem habitats sampled from 2 pre-established epidemiological sites in Togo were identified and recorded from July 2009 to June 2010. Initially the data was aggregated into proc genmod. An agglomerative hierarchical residual cluster-based analysis was then performed. The sampled clustered study site data was then analyzed for statistical correlations using Monthly Biting Rates (MBR). Euclidean distance measurements and terrain-related geomorphological statistics were then generated in ArcGIS. A digital overlay was then performed also in ArcGIS using the georeferenced ground coordinates of high and low density clusters stratified by Annual Biting Rates (ABR). This data was overlain onto multitemporal sub-meter pixel resolution satellite data (i.e., QuickBird 0.61m wavbands ). Orthogonal spatial filter eigenvectors were then generated in SAS/GIS. Univariate and non-linear regression-based models (i.e., Logistic, Poisson and Negative Binomial) were also employed to determine probability distributions and to identify statistically significant parameter estimators from the sampled data. Thereafter, Durbin-Watson test statistics were used to test the null hypothesis that the regression residuals were not autocorrelated against the alternative that the residuals followed an autoregressive process in AUTOREG. Bayesian uncertainty matrices were also constructed employing normal priors for each of the sampled estimators in PROC MCMC. The residuals revealed both spatially structured and unstructured error effects in the high and low ABR-stratified clusters. The analyses also revealed that the estimators, levels of turbidity and presence of rocks were statistically significant for the high-ABR-stratified clusters, while the estimators distance between habitats and floating vegetation were important for the low-ABR-stratified cluster. Varying and constant coefficient regression models, ABR- stratified GIS-generated clusters, sub-meter resolution satellite imagery, a robust residual intra-cluster diagnostic test, MBR-based histograms, eigendecomposition spatial filter algorithms and Bayesian matrices can enable accurate autoregressive estimation of latent uncertainity affects and other residual error probabilities (i.e., heteroskedasticity) for testing correlations between georeferenced S. damnosum s.l. riverine larval habitat estimators. The asymptotic distribution of the resulting residual adjusted intra-cluster predictor error autocovariate coefficients can thereafter be established while estimates of the asymptotic variance can lead to the construction of approximate confidence intervals for accurately targeting productive S. damnosum s.l habitats based on spatiotemporal field-sampled count data.

A lung cancer risk classifier comprising genome maintenance genes measured in normal bronchial epithelial cells.

PubMed

Yeo, Jiyoun; Crawford, Erin L; Zhang, Xiaolu; Khuder, Sadik; Chen, Tian; Levin, Albert; Blomquist, Thomas M; Willey, James C

2017-05-02

Annual low dose CT (LDCT) screening of individuals at high demographic risk reduces lung cancer mortality by more than 20%. However, subjects selected for screening based on demographic criteria typically have less than a 10% lifetime risk for lung cancer. Thus, there is need for a biomarker that better stratifies subjects for LDCT screening. Toward this goal, we previously reported a lung cancer risk test (LCRT) biomarker comprising 14 genome-maintenance (GM) pathway genes measured in normal bronchial epithelial cells (NBEC) that accurately classified cancer (CA) from non-cancer (NC) subjects. The primary goal of the studies reported here was to optimize the LCRT biomarker for high specificity and ease of clinical implementation. Targeted competitive multiplex PCR amplicon libraries were prepared for next generation sequencing (NGS) analysis of transcript abundance at 68 sites among 33 GM target genes in NBEC specimens collected from a retrospective cohort of 120 subjects, including 61 CA cases and 59 NC controls. Genes were selected for analysis based on contribution to the previously reported LCRT biomarker and/or prior evidence for association with lung cancer risk. Linear discriminant analysis was used to identify the most accurate classifier suitable to stratify subjects for screening. After cross-validation, a model comprising expression values from 12 genes (CDKN1A, E2F1, ERCC1, ERCC4, ERCC5, GPX1, GSTP1, KEAP1, RB1, TP53, TP63, and XRCC1) and demographic factors age, gender, and pack-years smoking, had Receiver Operator Characteristic area under the curve (ROC AUC) of 0.975 (95% CI: 0.96-0.99). The overall classification accuracy was 93% (95% CI 88%-98%) with sensitivity 93.1%, specificity 92.9%, positive predictive value 93.1% and negative predictive value 93%. The ROC AUC for this classifier was significantly better (p < 0.0001) than the best model comprising demographic features alone. The LCRT biomarker reported here displayed high accuracy and ease of implementation on a high throughput, quality-controlled targeted NGS platform. As such, it is optimized for clinical validation in specimens from the ongoing LCRT blinded prospective cohort study. Following validation, the biomarker is expected to have clinical utility by better stratifying subjects for annual lung cancer screening compared to current demographic criteria alone.

Regression analysis on the variation in efficiency frontiers for prevention stage of HIV/AIDS.

PubMed

Kamae, Maki S; Kamae, Isao; Cohen, Joshua T; Neumann, Peter J

2011-01-01

To investigate how the cost effectiveness of preventing HIV/AIDS varies across possible efficiency frontiers (EFs) by taking into account potentially relevant external factors, such as prevention stage, and how the EFs can be characterized using regression analysis given uncertainty of the QALY-cost estimates. We reviewed cost-effectiveness estimates for the prevention and treatment of HIV/AIDS published from 2002-2007 and catalogued in the Tufts Medical Center Cost-Effectiveness Analysis (CEA) Registry. We constructed efficiency frontier (EF) curves by plotting QALYs against costs, using methods used by the Institute for Quality and Efficiency in Health Care (IQWiG) in Germany. We stratified the QALY-cost ratios by prevention stage, country of study, and payer perspective, and estimated EF equations using log and square-root models. A total of 53 QALY-cost ratios were identified for HIV/AIDS in the Tufts CEA Registry. Plotted ratios stratified by prevention stage were visually grouped into a cluster consisting of primary/secondary prevention measures and a cluster consisting of tertiary measures. Correlation coefficients for each cluster were statistically significant. For each cluster, we derived two EF equations - one based on the log model, and one based on the square-root model. Our findings indicate that stratification of HIV/AIDS interventions by prevention stage can yield distinct EFs, and that the correlation and regression analyses are useful for parametrically characterizing EF equations. Our study has certain limitations, such as the small number of included articles and the potential for study populations to be non-representative of countries of interest. Nonetheless, our approach could help develop a deeper appreciation of cost effectiveness beyond the deterministic approach developed by IQWiG.

Medical therapy v. PCI in stable coronary artery disease: a cost-effectiveness analysis.

PubMed

Wijeysundera, Harindra C; Tomlinson, George; Ko, Dennis T; Dzavik, Vladimir; Krahn, Murray D

2013-10-01

Percutaneous coronary intervention (PCI) with either drug-eluting stents (DES) or bare metal stents (BMS) reduces angina and repeat procedures compared with optimal medical therapy alone. It remains unclear if these benefits are sufficient to offset their increased costs and small increase in adverse events. Cost utility analysis of initial medical therapy v. PCI with either BMS or DES. . Markov cohort decision model. Data Sources. Propensity-matched observational data from Ontario, Canada, for baseline event rates. Effectiveness and utility data obtained from the published literature, with costs from the Ontario Case Costing Initiative. Patients with stable coronary artery disease, confirmed after angiography, stratified by risk of restenosis based on diabetic status, lesion size, and lesion length. Time Horizon. Lifetime. Perspective. Ontario Ministry of Health and Long Term Care. Interventions. Optimal medical therapy, PCI with BMS or DES. Lifetime costs, quality-adjusted life years (QALYs), and the incremental cost-effectiveness ratio (ICER). of Base Case Analysis. In the overall population, medical therapy had the lowest lifetime costs at $22,952 v. $25,081 and $25,536 for BMS and DES, respectively. Medical therapy had a quality-adjusted life expectancy of 10.1 v. 10.26 QALYs for BMS, producing an ICER of $13,271/QALY. The DES strategy had a quality-adjusted life expectancy of only 10.20 QALYs and was dominated by the BMS strategy. This ranking was consistent in all groups stratified by restenosis risk, except diabetic patients with long lesions in small arteries, in whom DES was cost-effective compared with medical therapy (ICER of $18,826/QALY). Limitations. There is the possibility of residual unobserved confounding. In patients with stable coronary artery disease, an initial BMS strategy is cost-effective.

XPG genetic polymorphisms and clinical outcome of patients with advanced non-small cell lung cancer under platinum-based treatment: a meta-analysis of 12 studies.

PubMed

Xiang, Tianxin; Kang, Xiuhua; Gong, Zhenghua; Bai, Wei; Chen, Chuanhui; Zhang, Wei

2017-04-01

A number of studies on the relationship between xeroderma pigmentosum group G (XPG) polymorphisms and clinical outcomes in non-small cell cancer (NSCLC) have led to inconclusive results. This meta-analysis evaluates the predictive value of XPG polymorphisms on the treatment response rate and overall survival of patients with NSCLC. To measure the correlative strength of the relationship between XPG polymorphisms and outcomes of patients with NSCLC, we searched electronic databases, including PubMed and China National Knowledge Infrastructure, to retrieve studies up to August 2016. We also employed pooled odds ratios (ORs) and hazard ratios (HRs) corresponding to 95% confidence intervals (95% CIs). Twelve studies involving 2877 patients with NSCLC were included: 8 studies involving 1473 patients examined the correlation between XPG polymorphisms and tumor response rate and 7 studies involving 2329 patients reported on the correlation of XPG polymorphisms with overall survival. None of the XPG His1104Asp(C>G)/His46His(C>T) polymorphisms exhibited a correlation with treatment response rate or overall survival. However, in a further stratified analysis by ethnicity, carriers of the 1104G allele were associated with good response among Asians in the homozygote model (GG vs. CC: OR = 1.57, 95% CI: 1.05-2.34, P = 0.027). Meanwhile, further stratified by ethnicity, His46His polymorphism was not associated with RR and OS in any genetic models. No strong evidence was found to support the use of XPG polymorphisms as tumor response and prognostic factors of patients with NSCLC receiving a platinum-based treatment regimen, which is attributed to marginal association. Studies with large-scale and multiple ethnicities need to be conducted to verify the conclusion.

Randomization in cancer clinical trials: permutation test and development of a computer program.

PubMed Central

Ohashi, Y

1990-01-01

When analyzing cancer clinical trial data where the treatment allocation is done using dynamic balancing methods such as the minimization method for balancing the distribution of important prognostic factors in each arm, conservativeness occurs if such a randomization scheme is ignored and a simple unstratified analysis is carried out. In this paper, the above conservativeness is demonstrated by computer simulation, and the development of a computer program that carries out permutation tests of the log-rank statistics for clinical trial data where the allocation is done by the minimization method or a stratified permuted block design is introduced. We are planning to use this program in practice to supplement a usual stratified analysis and model-based methods such as the Cox regression. The most serious problem in cancer clinical trials in Japan is how to carry out the quality control or data management in trials that are initiated and conducted by researchers without support from pharmaceutical companies. In the final section of this paper, one international collaborative work for developing international guidelines on data management in clinical trials of bladder cancer is briefly introduced, and the differences between the system adopted in US/European statistical centers and the Japanese system is described. PMID:2269216

Cure of cancer for seven cancer sites in the Flemish Region.

PubMed

Silversmit, Geert; Jegou, David; Vaes, Evelien; Van Hoof, Elke; Goetghebeur, Els; Van Eycken, Liesbet

2017-03-01

Cumulative relative survival curves for many cancers reach a plateau several years after diagnosis, indicating that the cancer survivor group has reached "statistical" cure. Parametric mixture cure model analysis on grouped relative survival curves provide an interesting way to determine the proportion of statistically cured cases and the mean survival time of the fatal cases in particular for population-based cancer registries. Based on the relative survival data from the Belgian Cancer Registry, parametric cure models were applied to seven cancer sites (cervix, colon, corpus uteri, skin melanoma, pancreas, stomach and oesophagus), at the Flemish Regional level for the incidence period 1999-2011. Statistical cure was observed for the examined cancer sites except for oesophageal cancer. The estimated cured proportion ranged from 5.9% [5.7, 6.1] for pancreatic cancer to 80.8% [80.5, 81.2] for skin melanoma. Cure results were further stratified by gender or age group. Stratified cured proportions were higher for females compared to males in colon cancer, stomach cancer, pancreas cancer and skin melanoma, which can mainly be attributed to differences in stage and age distribution between both sexes. This study demonstrates the applicability of cure rate models for the selected cancer sites after 14 years of follow-up and presents the first population-based results on the cure of cancer in Belgium. © 2016 UICC.

Susceptibility to Exercise-Induced Muscle Damage: a Cluster Analysis with a Large Sample.

PubMed

Damas, F; Nosaka, K; Libardi, C A; Chen, T C; Ugrinowitsch, C

2016-07-01

We investigated the responses of indirect markers of exercise-induced muscle damage (EIMD) among a large number of young men (N=286) stratified in clusters based on the largest decrease in maximal voluntary contraction torque (MVC) after an unaccustomed maximal eccentric exercise bout of the elbow flexors. Changes in MVC, muscle soreness (SOR), creatine kinase (CK) activity, range of motion (ROM) and upper-arm circumference (CIR) before and for several days after exercise were compared between 3 clusters established based on MVC decrease (low, moderate, and high responders; LR, MR and HR). Participants were allocated to LR (n=61), MR (n=152) and HR (n=73) clusters, which depicted significantly different cluster centers of 82%, 61% and 42% of baseline MVC, respectively. Once stratified by MVC decrease, all muscle damage markers were significantly different between clusters following the same pattern: small changes for LR, larger changes for MR, and the largest changes for HR. Stratification of individuals based on the magnitude of MVC decrease post-exercise greatly increases the precision in estimating changes in EIMD by proxy markers such as SOR, CK activity, ROM and CIR. This indicates that the most commonly used markers are valid and MVC orchestrates their responses, consolidating the role of MVC as the best EIMD indirect marker. © Georg Thieme Verlag KG Stuttgart · New York.

Morphology of the epithelium of the lower rectum and the anal canal in the adult human.

PubMed

Tanaka, Eiichi; Noguchi, Tsuyoshi; Nagai, Kaoruko; Akashi, Yuichi; Kawahara, Katsunobu; Shimada, Tatsuo

2012-06-01

The anal canal is an important body part clinically. However, there is no agreement about the epithelium of the anal canal, the anal transitional zone (ATZ) epithelium in particular. The aim of this study is to clarify the structure of the epithelium of the human lower rectum and anal canal. Intact rectum and anus obtained from patients who underwent surgery for rectal carcinoma were examined by light and scanning electron microscopy (LM and SEM). By LM, three types of epithelium were observed in the anal canal: simple columnar epithelium, stratified squamous epithelium, and stratified columnar epithelium. The lower rectum was composed of simple columnar epithelium. SEM findings showed stratified squamous epithelium that consisted of squamous cells with microridges, changing to simple columnar epithelium consisting of columnar cells with short microvilli at the anorectal line. LM and SEM observations in a one-to-one ratio revealed that the area of stratified columnar epithelium based on LM corresponded to the anal crypt and sinus. In conclusion, the epithelium of the human anal canal was fundamentally composed of simple columnar epithelium and stratified squamous epithelium. We found no evidence of the ATZ.

Treatment strategies in the acute therapy of migraine: stratified care and early intervention.

PubMed

D'Amico, D; Moschiano, F; Usai, S; Bussone, G

2006-05-01

Various treatment strategies have been proposed to help clinicians provide the most effective acute treatment for migraine patients. Stratified care is based on the concept that the most appropriate initial treatment can be prescribed after evaluation of each patient's headache characteristics. The results of a large multicentre trial showed that when patients were stratified according to disability grade, clinical outcomes were significantly better than with step-care approaches. Prospective studies have shown that treating migraines with triptans when pain is mild (early intervention) considerably increases success rates for endpoints (pain-free at 2 h, sustained pain-free state) for which triptans had relatively poor efficacy in pivotal trials, and which contribute most to patient satisfaction. Stratified care and early treatment are also cost-effective. However these strategies are not suitable for all patients. Stratified care may be rendered difficult by medication contraindications and changes in attack characteristics over time. Early triptan intervention carries a risk of medication overuse and might not be indicated in patients with lack of pain progression. Successful implementation of both strategies requires that physicians are well informed, and that they elicit an exhaustive headache history from each patient.

CT-based texture analysis potentially provides prognostic information complementary to interim fdg-pet for patients with hodgkin's and aggressive non-hodgkin's lymphomas.

PubMed

Ganeshan, B; Miles, K A; Babikir, S; Shortman, R; Afaq, A; Ardeshna, K M; Groves, A M; Kayani, I

2017-03-01

The purpose of this study was to investigate the ability of computed tomography texture analysis (CTTA) to provide additional prognostic information in patients with Hodgkin's lymphoma (HL) and high-grade non-Hodgkin's lymphoma (NHL). This retrospective, pilot-study approved by the IRB comprised 45 lymphoma patients undergoing routine 18F-FDG-PET-CT. Progression-free survival (PFS) was determined from clinical follow-up (mean-duration: 40 months; range: 10-62 months). Non-contrast-enhanced low-dose CT images were submitted to CTTA comprising image filtration to highlight features of different sizes followed by histogram-analysis using kurtosis. Prognostic value of CTTA was compared to PET FDG-uptake value, tumour-stage, tumour-bulk, lymphoma-type, treatment-regime, and interim FDG-PET (iPET) status using Kaplan-Meier analysis. Cox regression analysis determined the independence of significantly prognostic imaging and clinical features. A total of 27 patients had aggressive NHL and 18 had HL. Mean PFS was 48.5 months. There was no significant difference in pre-treatment CTTA between the lymphoma sub-types. Kaplan-Meier analysis found pre-treatment CTTA (medium feature scale, p=0.010) and iPET status (p<0.001) to be significant predictors of PFS. Cox analysis revealed that an interaction between pre-treatment CTTA and iPET status was the only independent predictor of PFS (HR: 25.5, 95% CI: 5.4-120, p<0.001). Specifically, pre-treatment CTTA risk stratified patients with negative iPET. CTTA can potentially provide prognostic information complementary to iPET for patients with HL and aggressive NHL. • CT texture-analysis (CTTA) provides prognostic information complementary to interim FDG-PET in Lymphoma. • Pre-treatment CTTA and interim PET status were significant predictors of progression-free survival. • Patients with negative interim PET could be further stratified by pre-treatment CTTA. • Provide precision surveillance where additional imaging reserved for patients at greatest recurrence-risk. • Assists in risk-adapted treatment strategy based on interim PET and CTTA.

Modified Team-Based Learning in an Ophthalmology Clerkship in China

PubMed Central

Zhou, Yuxian; Ao, Yong; Xin, Wei; Jia, Yu; Yang, Ying; Cai, Yu; Xu, Chaochao; Yang, Yangfan; Lin, Haotian

2016-01-01

Objective Team-based learning (TBL) is an increasingly popular teaching method in medical education. However, TBL hasn’t been well-studied in the ophthalmology clerkship context. This study was to examine the impact of modified TBL in such context and to assess the student evaluations of TBL. Methods Ninety-nine students of an 8-year clinical medicine program from Zhongshan Ophthalmic Centre, Sun Yat-sen University, were randomly divided into four sequential units and assigned to six teams with the same faculty. The one-week ophthalmology clerkship module included traditional lectures, gross anatomy and a TBL module. The effects of the TBL module on student performance were measured by the Individual Readiness Assurance Test (IRAT), the Group Readiness Assurance Test (GRAT), the Group Application Problem (GAP) and final examination scores (FESs). Students’ evaluations of TBL were measured by a 16-item questionnaire. IRAT and GRAT scores were compared using a paired t-test. One-way analysis of variance (ANOVA) and subgroup analysis compared the effects among quartiles that were stratified by the Basic Ophthalmology Levels (BOLs). The BOLs were evaluated before the ophthalmology clerkship. Results In TBL classes, the GRAT scores were significantly higher than the IRAT scores in both the full example and the BOL-stratified groups. It highlighted the advantages of TBL compared to the individual learning. Quartile-stratified ANOVA comparisons showed significant differences at FES scores (P < 0.01). In terms to IRAT, GRAT and GAP scores, there was no significant result. Moreover, IRAT scores only significantly differed between the first and fourth groups. The FES scores of the first three groups are significantly higher than the fourth group. Gender-specific differences were significant in FES but not the IRAT. Overall, 57.65% of student respondents agreed that TBL was helpful. Male students tended to rate TBL higher than female students. Conclusion The application of modified TBL to the ophthalmology clerkship curriculum improved students’ performance and increased students’ engagement and satisfaction. TBL should be further optimized and developed to enhance the educational outcomes among multi-BOLs medical students. PMID:27100286

Post-stroke hemiparesis: Does chronicity, etiology, and lesion side are associated with gait pattern?

PubMed

Gama, Gabriela Lopes; Larissa, Coutinho de Lucena; Brasileiro, Ana Carolina de Azevedo Lima; Silva, Emília Márcia Gomes de Souza; Galvão, Élida Rayanne Viana Pinheiro; Maciel, Álvaro Cavalcanti; Lindquist, Ana Raquel Rodrigues

2017-07-01

Studies that evaluate gait rehabilitation programs for individuals with stroke often consider time since stroke of more than six months. In addition, most of these studies do not use lesion etiology or affected cerebral hemisphere as study factors. However, it is unknown whether these factors are associated with post-stroke motor performance after the spontaneous recovery period. To investigate whether time since stroke onset, etiology, and lesion side is associated with spatiotemporal and angular gait parameters of individuals with chronic stroke. Fifty individuals with chronic hemiparesis (20 women) were evaluated. The sample was stratified according to time since stroke (between 6 and 12 months, between 13 and 36 months, and over 36 months), affected cerebral hemisphere (left or right) and lesion etiology (ischemic and hemorrhagic). The participants were evaluated during overground walking at self-selected gait speed, and spatiotemporal and angular gait parameters were calculated. Results Differences between gait speed, stride length, hip flexion, and knee flexion were observed in subgroups stratified based on lesion etiology. Survivors of a hemorrhagic stroke exhibited more severe gait impairment. Subgroups stratified based on time since stroke only showed intergroup differences for stride length, and subgroups stratified based on affected cerebral hemisphere displayed between-group differences for swing time symmetry ratio. In order to recruit a more homogeneous sample, more accurate results were obtained and an appropriate rehabilitation program was offered, researchers and clinicians should consider that gait pattern might be associated with time since stroke, affected cerebral hemisphere and lesion etiology.

Numerical simulation of stratified flows from laboratory experiments to coastal ocean

NASA Astrophysics Data System (ADS)

Fraunie, Philippe

2014-05-01

Numeric modeling of a flow past vertical strip uniformly towing with permanent velocity in horizontal direction in a linearly stratified talk which was based on a finite differences solver adapted to the low Reynolds Navier-Stokes equation with transport equation for salinity (LES simulation [6]) has demonstrated reasonable agreement with data of schlieren visualization, density marker and probe measurements of internal wave fields. Another approach based on two different numerical methods for one specific case of stably stratified incompressible flow was developed, using the compact finite-difference discretizations. The numerical scheme itself follows the principle of semi-discretisation, with high order compact discretisation in space, while the time integration is carried out by the Strong Stability Preserving Runge-Kutta scheme. Results were compared against the reference solution obtained by the AUSM finite volume method [7]. The test case allowed demonstrating the ability of selected numerical methods to represent stably stratified flows over horizontal strip [4] and hill type 2D obstacles [1, 3] with generation of internal waves. From previous LES [4] and RANS [8] realistic simulations code, the ability of research codes to reproduce field observations is discussed. ACKNOWLEDGMENTS This research work was supported by Region Provence Alpes Côte d'Azur - Modtercom project, the Research Plan MSM 6840770010 of the Ministry of education of Czech Republic and the Russian Foundation for Basic Research (grant 12-01-00128). REFERENCES 1. Chashechkin Yu.D., Mitkin V.V. Experimental study of a fine structure of 2D wakes and mixing past an obstacle in a continuously stratified fluid // Dynamics of Atmosphere and Oceans. 2001. V. 34. P. 165-187. 2. Chashechkin, Yu. D. Hydrodynamics of a sphere in a stratified fluid // Fluid Dyn. 1989. V.24(1) P. 1-7. 3. Mitkin V. V., Chashechkin Yu. D. Transformation of hanging discontinuities into vortex systems in a stratified flow behind a cylinder // 2007. Fluid Dyn. V. 42 (1). P. 12-23. 4. Bardakov R. N., Mitkin V. V., Chashechkin Yu. D. Fine structure of a stratified flow near a flat-plate surface // J. Appl. Mech. Tech. Phys. 2007. V. 48(6) P. 840-851. 5. Chashechkin Yu. D., Mitkin V. V. An effect of a lift force on the structure of attached internal waves in a continuously stratified fluid // Dokl. Phys. 2001. V. 46 (6). P. 425-428. 6. Houcine H., Chashechkin Yu.D, Fraunié P., Fernando H.J.S., Gharbi A., Lili T. Numerical modeling of the generation of internal waves by uniform stratified flow over a thin vertical barrier // Int J. Num Methods in Fluids. 2012. V.68(4). P. 451-466. DOI: 10.1002/fld.2513 7. Bodnar T., Benes , Fraunié P., Kozel K.. Application of Compact Finite-Difference Schemes to Simulations of Stably Stratified Fluid Flows. Applied Mathematics and Computation 219 : 3336-3353 2012. doi:10.1016/j.amc.2011.08.058 8. Schaeffer A. Molcard A. Forget P. Fraunié P. Garreau P. Generation mechanisms for mesoscale eddies in the Gulf of Lions: radar observation and modelling. Ocean Dynamics vol 61, 10, pp1587-1609, 2011. DOI.1007/s10236-011-0482-8.

Development of portable defocusing micro-scale spatially offset Raman spectroscopy.

PubMed

Realini, Marco; Botteon, Alessandra; Conti, Claudia; Colombo, Chiara; Matousek, Pavel

2016-05-10

We present, for the first time, portable defocusing micro-Spatially Offset Raman Spectroscopy (micro-SORS). Micro-SORS is a concept permitting the analysis of thin, highly turbid stratified layers beyond the reach of conventional Raman microscopy. The technique is applicable to the analysis of painted layers in cultural heritage (panels, canvases and mural paintings, painted statues and decorated objects in general) as well as in many other areas including polymer, biological and biomedical applications, catalytic and forensics sciences where highly turbid stratified layers are present and where invasive analysis is undesirable or impossible. So far the technique has been demonstrated only on benchtop Raman microscopes precluding the non-invasive analysis of larger samples and samples in situ. The new set-up is characterised conceptually on a range of artificially assembled two-layer systems demonstrating its benefits and performance across several application areas. These included stratified polymer sample, pharmaceutical tablet and layered paint samples. The same samples were also analysed by a high performance (non-portable) benchtop Raman microscope to provide benchmarking against our earlier research. The realisation of the vision of delivering portability to micro-SORS has a transformative potential spanning across multiple disciplines as it fully unlocks, for the first time, the non-invasive and non-destructive aspects of micro-SORS enabling it to be applied also to large and non-portable samples in situ without recourse to removing samples, or their fragments, for laboratory analysis on benchtop Raman microscopes.

Identifying Treatment Effect Modifiers in the STarT Back Trial: A Secondary Analysis.

PubMed

Beneciuk, Jason M; Hill, Jonathan C; Campbell, Paul; Afolabi, Ebenezer; George, Steven Z; Dunn, Kate M; Foster, Nadine E

2017-01-01

Identification of patient characteristics influencing treatment outcomes is a top low back pain (LBP) research priority. Results from the STarT Back trial support the effectiveness of prognostic stratified care for LBP compared with current best care, however, patient characteristics associated with treatment response have not yet been explored. The purpose of this secondary analysis was to identify treatment effect modifiers within the STarT Back trial at 4-month follow-up (n = 688). Treatment response was dichotomized using back-specific physical disability measured using the Roland-Morris Disability Questionnaire (≥7). Candidate modifiers were identified using previous literature and evaluated using logistic regression with statistical interaction terms to provide preliminary evidence of treatment effect modification. Socioeconomic status (SES) was identified as an effect modifier for disability outcomes (odds ratio [OR] = 1.71, P = .028). High SES patients receiving prognostic stratified care were 2.5 times less likely to have a poor outcome compared with low SES patients receiving best current care (OR = .40, P = .006). Education level (OR = 1.33, P = .109) and number of pain medications (OR = .64, P = .140) met our criteria for effect modification with weaker evidence (.20 > P ≥ .05). These findings provide preliminary evidence for SES, education, and number of pain medications as treatment effect modifiers of prognostic stratified care delivered in the STarT Back Trial. This analysis provides preliminary exploratory findings about the characteristics of patients who might least likely benefit from targeted treatment using prognostic stratified care for LBP. Copyright © 2016 American Pain Society. Published by Elsevier Inc. All rights reserved.

First Investigation of Microbial Community Composition in the Bridge (Gadeok Channel) between the Jinhae-Masan Bay and the South Sea of Korea

NASA Astrophysics Data System (ADS)

Lee, Jiyoung; Lim, Jae-Hyun; Park, Junhyung; Youn, Seok-Hyun; Oh, Hyun-Ju; Kim, Ju-Hyoung; Kim, Myung Kyum; Cho, Hyeyoun; Yoon, Joo-Eun; Kim, Soyeon; Markkandan, Kesavan; Park, Ki-Tae; Kim, Il-Nam

2018-02-01

Microbial community composition varies based on seasonal dynamics (summer: strongly stratified water column; autumn: weakly stratified water column; winter: vertically homogeneous water column) and vertical distributions (surface, middle, and bottom depths) in the Gadeok Channel, which is the primary passage to exchange waters and materials between the Jinhae-Masan Bay and the South Sea waters. The microbial community composition was analyzed from June to December 2016 using 16S rRNA gene sequencing. The community was dominated by the phyla Proteobacteria (45%), Bacteroidetes (18%), Cyanobacteria (15%), Verrucomicrobia (6%), and Actinobacteria (6%). Alphaproteobacteria (29%) was the most abundant microbial class, followed by Flavobacteria (15%) and Gammaproteobacteria (15%) in all samples. The composition of the microbial communities was found to vary vertically and seasonally. The orders Flavobacteriales and Stramenopiles showed opposing seasonal patterns; Flavobacteriales was more abundant in August and December while Stramenopiles showed high abundance in June and October at all depths. The genus Synechococcus reached extremely high abundance (14%) in the June surface water column, but was much less abundant in December water columns. Clustering analysis showed that there was a difference in the microbial community composition pattern between the strongly stratified season and well-mixed season. These results indicate that the seasonal dynamics of physicochemical and hydrologic conditions throughout the water column are important parameters in shaping the microbial community composition in the Gadeok Channel.

Reuse, Recycle, Reweigh: Combating Influenza through Efficient Sequential Bayesian Computation for Massive Data.

PubMed

Tom, Jennifer A; Sinsheimer, Janet S; Suchard, Marc A

Massive datasets in the gigabyte and terabyte range combined with the availability of increasingly sophisticated statistical tools yield analyses at the boundary of what is computationally feasible. Compromising in the face of this computational burden by partitioning the dataset into more tractable sizes results in stratified analyses, removed from the context that justified the initial data collection. In a Bayesian framework, these stratified analyses generate intermediate realizations, often compared using point estimates that fail to account for the variability within and correlation between the distributions these realizations approximate. However, although the initial concession to stratify generally precludes the more sensible analysis using a single joint hierarchical model, we can circumvent this outcome and capitalize on the intermediate realizations by extending the dynamic iterative reweighting MCMC algorithm. In doing so, we reuse the available realizations by reweighting them with importance weights, recycling them into a now tractable joint hierarchical model. We apply this technique to intermediate realizations generated from stratified analyses of 687 influenza A genomes spanning 13 years allowing us to revisit hypotheses regarding the evolutionary history of influenza within a hierarchical statistical framework.

Reuse, Recycle, Reweigh: Combating Influenza through Efficient Sequential Bayesian Computation for Massive Data

PubMed Central

Tom, Jennifer A.; Sinsheimer, Janet S.; Suchard, Marc A.

2015-01-01

Massive datasets in the gigabyte and terabyte range combined with the availability of increasingly sophisticated statistical tools yield analyses at the boundary of what is computationally feasible. Compromising in the face of this computational burden by partitioning the dataset into more tractable sizes results in stratified analyses, removed from the context that justified the initial data collection. In a Bayesian framework, these stratified analyses generate intermediate realizations, often compared using point estimates that fail to account for the variability within and correlation between the distributions these realizations approximate. However, although the initial concession to stratify generally precludes the more sensible analysis using a single joint hierarchical model, we can circumvent this outcome and capitalize on the intermediate realizations by extending the dynamic iterative reweighting MCMC algorithm. In doing so, we reuse the available realizations by reweighting them with importance weights, recycling them into a now tractable joint hierarchical model. We apply this technique to intermediate realizations generated from stratified analyses of 687 influenza A genomes spanning 13 years allowing us to revisit hypotheses regarding the evolutionary history of influenza within a hierarchical statistical framework. PMID:26681992

Hierarchical model analysis of the Atlantic Flyway Breeding Waterfowl Survey

USGS Publications Warehouse

Sauer, John R.; Zimmerman, Guthrie S.; Klimstra, Jon D.; Link, William A.

2014-01-01

We used log-linear hierarchical models to analyze data from the Atlantic Flyway Breeding Waterfowl Survey. The survey has been conducted by state biologists each year since 1989 in the northeastern United States from Virginia north to New Hampshire and Vermont. Although yearly population estimates from the survey are used by the United States Fish and Wildlife Service for estimating regional waterfowl population status for mallards (Anas platyrhynchos), black ducks (Anas rubripes), wood ducks (Aix sponsa), and Canada geese (Branta canadensis), they are not routinely adjusted to control for time of day effects and other survey design issues. The hierarchical model analysis permits estimation of year effects and population change while accommodating the repeated sampling of plots and controlling for time of day effects in counting. We compared population estimates from the current stratified random sample analysis to population estimates from hierarchical models with alternative model structures that describe year to year changes as random year effects, a trend with random year effects, or year effects modeled as 1-year differences. Patterns of population change from the hierarchical model results generally were similar to the patterns described by stratified random sample estimates, but significant visibility differences occurred between twilight to midday counts in all species. Controlling for the effects of time of day resulted in larger population estimates for all species in the hierarchical model analysis relative to the stratified random sample analysis. The hierarchical models also provided a convenient means of estimating population trend as derived statistics from the analysis. We detected significant declines in mallard and American black ducks and significant increases in wood ducks and Canada geese, a trend that had not been significant for 3 of these 4 species in the prior analysis. We recommend using hierarchical models for analysis of the Atlantic Flyway Breeding Waterfowl Survey.

Implementing the Keele stratified care model for patients with low back pain: an observational impact study.

PubMed

Bamford, Adrian; Nation, Andy; Durrell, Susie; Andronis, Lazaros; Rule, Ellen; McLeod, Hugh

2017-02-03

The Keele stratified care model for management of low back pain comprises use of the prognostic STarT Back Screening Tool to allocate patients into one of three risk-defined categories leading to associated risk-specific treatment pathways, such that high-risk patients receive enhanced treatment and more sessions than medium- and low-risk patients. The Keele model is associated with economic benefits and is being widely implemented. The objective was to assess the use of the stratified model following its introduction in an acute hospital physiotherapy department setting in Gloucestershire, England. Physiotherapists recorded data on 201 patients treated using the Keele model in two audits in 2013 and 2014. To assess whether implementation of the stratified model was associated with the anticipated range of treatment sessions, regression analysis of the audit data was used to determine whether high- or medium-risk patients received significantly more treatment sessions than low-risk patients. The analysis controlled for patient characteristics, year, physiotherapists' seniority and physiotherapist. To assess the physiotherapists' views on the usefulness of the stratified model, audit data on this were analysed using framework methods. To assess the potential economic consequences of introducing the stratified care model in Gloucestershire, published economic evaluation findings on back-related National Health Service (NHS) costs, quality-adjusted life years (QALYs) and societal productivity losses were applied to audit data on the proportion of patients by risk classification and estimates of local incidence. When the Keele model was implemented, patients received significantly more treatment sessions as the risk-rating increased, in line with the anticipated impact of targeted treatment pathways. Physiotherapists were largely positive about using the model. The potential annual impact of rolling out the model across Gloucestershire is a gain in approximately 30 QALYs, a reduction in productivity losses valued at £1.4 million and almost no change to NHS costs. The Keele model was implemented and risk-specific treatment pathways successfully used for patients presenting with low back pain. Applying published economic evidence to the Gloucestershire locality suggests that substantial health and productivity outcomes would be associated with rollout of the Keele model while being cost-neutral for the NHS.

Calculation of periodic flows in a continuously stratified fluid

NASA Astrophysics Data System (ADS)

Vasiliev, A.

2012-04-01

Analytic theory of disturbances generated by an oscillating compact source in a viscous continuously stratified fluid was constructed. Exact solution of the internal waves generation problem was constructed taking into account diffusivity effects. This analysis is based on set of fundamental equations of incompressible flows. The linearized problem of periodic flows in a continuously stratified fluid, generated by an oscillating part of the inclined plane was solved by methods of singular perturbation theory. A rectangular or disc placed on a sloping plane and oscillating linearly in an arbitrary direction was selected as a source of disturbances. The solutions include regularly perturbed on dissipative component functions describing internal waves and a family of singularly perturbed functions. One of the functions from the singular components family has an analogue in a homogeneous fluid that is a periodic or Stokes' flow. Its thickness is defined by a universal micro scale depending on kinematics viscosity coefficient and a buoyancy frequency with a factor depending on the wave slope. Other singular perturbed functions are specific for stratified flows. Their thickness are defined the diffusion coefficient, kinematic viscosity and additional factor depending on geometry of the problem. Fields of fluid density, velocity, vorticity, pressure, energy density and flux as well as forces acting on the source are calculated for different types of the sources. It is shown that most effective source of waves is the bi-piston. Complete 3D problem is transformed in various limiting cases that are into 2D problem for source in stratified or homogeneous fluid and the Stokes problem for an oscillating infinite plane. The case of the "critical" angle that is equality of the emitting surface and the wave cone slope angles needs in separate investigations. In this case, the number of singular component is saved. Patterns of velocity and density fields were constructed and analyzed by methods of computational mathematics. Singular components of the solution affect the flow pattern of the inhomogeneous stratified fluid, not only near the source of the waves, but at a large distance. Analytical calculations of the structure of wave beams are matched with laboratory experiments. Some deviations at large distances from the source are formed due to the contribution of background wave field associated with seiches in the laboratory tank. In number of the experiments vortices with closed contours were observed on some distances from the disk. The work was supported by Ministry of Education and Science RF (Goscontract No. 16.518.11.7059), experiments were performed on set up USU "HPC IPMec RAS".

Performance of Stratified and Subgrouped Disproportionality Analyses in Spontaneous Databases.

PubMed

Seabroke, Suzie; Candore, Gianmario; Juhlin, Kristina; Quarcoo, Naashika; Wisniewski, Antoni; Arani, Ramin; Painter, Jeffery; Tregunno, Philip; Norén, G Niklas; Slattery, Jim

2016-04-01

Disproportionality analyses are used in many organisations to identify adverse drug reactions (ADRs) from spontaneous report data. Reporting patterns vary over time, with patient demographics, and between different geographical regions, and therefore subgroup analyses or adjustment by stratification may be beneficial. The objective of this study was to evaluate the performance of subgroup and stratified disproportionality analyses for a number of key covariates within spontaneous report databases of differing sizes and characteristics. Using a reference set of established ADRs, signal detection performance (sensitivity and precision) was compared for stratified, subgroup and crude (unadjusted) analyses within five spontaneous report databases (two company, one national and two international databases). Analyses were repeated for a range of covariates: age, sex, country/region of origin, calendar time period, event seriousness, vaccine/non-vaccine, reporter qualification and report source. Subgroup analyses consistently performed better than stratified analyses in all databases. Subgroup analyses also showed benefits in both sensitivity and precision over crude analyses for the larger international databases, whilst for the smaller databases a gain in precision tended to result in some loss of sensitivity. Additionally, stratified analyses did not increase sensitivity or precision beyond that associated with analytical artefacts of the analysis. The most promising subgroup covariates were age and region/country of origin, although this varied between databases. Subgroup analyses perform better than stratified analyses and should be considered over the latter in routine first-pass signal detection. Subgroup analyses are also clearly beneficial over crude analyses for larger databases, but further validation is required for smaller databases.

Integral Equation Method for Electromagnetic Wave Propagation in Stratified Anisotropic Dielectric-Magnetic Materials

NASA Astrophysics Data System (ADS)

Shu, Wei-Xing; Fu, Na; Lü, Xiao-Fang; Luo, Hai-Lu; Wen, Shuang-Chun; Fan, Dian-Yuan

2010-11-01

We investigate the propagation of electromagnetic waves in stratified anisotropic dielectric-magnetic materials using the integral equation method (IEM). Based on the superposition principle, we use Hertz vector formulations of radiated fields to study the interaction of wave with matter. We derive in a new way the dispersion relation, Snell's law and reflection/transmission coefficients by self-consistent analyses. Moreover, we find two new forms of the generalized extinction theorem. Applying the IEM, we investigate the wave propagation through a slab and disclose the underlying physics, which are further verified by numerical simulations. The results lead to a unified framework of the IEM for the propagation of wave incident either from a medium or vacuum in stratified dielectric-magnetic materials.

Oil-Water Flow Investigations using Planar-Laser Induced Fluorescence and Particle Velocimetry

NASA Astrophysics Data System (ADS)

Ibarra, Roberto; Matar, Omar K.; Markides, Christos N.

2017-11-01

The study of the complex behaviour of immiscible liquid-liquid flow in pipes requires the implementation of advanced measurement techniques in order to extract detailed in situ information. Laser-based diagnostic techniques allow the extraction of high-resolution space- and time resolve phase and velocity information, which aims to improve the fundamental understanding of these flows and to validate closure relations for advanced multiphase flow models. This work shows a novel simultaneous planar-laser induced fluorescence and particle velocimetry in stratified oil-water flows using two laser light sheets at two different wavelengths for fluids with different refractive indices at horizontal and upward pipe inclinations (<5°) in stratified flow conditions (i.e. separated layers). Complex flow structures are extracted from 2-D instantaneous velocity fields, which are strongly dependent on the pipe inclination at low velocities. The analysis of mean wall-normal velocity profiles and velocity fluctuations suggests the presence of single- and counter-rotating vortices in the azimuthal direction, especially in the oil layer, which can be attributed to the influence of the interfacial waves. Funding from BP, and the TMF Consortium is gratefully acknowledged.

Methionine Synthase A2756G Polymorphism and Risk of Colorectal Adenoma and Cancer: Evidence Based on 27 Studies

PubMed Central

Jiang, Xun; Lu, Lie-sheng

2013-01-01

Methionine synthase (MTR), which plays a central role in maintaining adequate intracellular folate, methionine and normal homocysteine concentrations, was thought to be involved in the development of colorectal cancer (CRC) and colorectal adenoma (CRA) by affecting DNA methylation. However, studies on the association between MTR A2756G polymorphism and CRC/CRA remain conflicting. We conducted a meta-analysis of 27 studies, including 13465 cases and 20430 controls for CRC, and 4844 cases and 11743 controls for CRA. Potential sources of heterogeneity and publication bias were also systematically explored. Overall, the summary odds ratio of G variant for CRC was 1.03 (95% CI: 0.96–1.09) and 1.05 (95% CI: 0.99–1.12) for CRA. No significant results were observed in heterozygous and homozygous when compared with wild genotype for these polymorphisms. In the stratified analyses according to ethnicity, source of controls, sample size, sex, and tumor site, no evidence of any gene-disease association was obtained. Results from the meta-analysis of four studies on MTR stratified according to smoking and alcohol drinking status showed an increased CRC risk in heavy smokers (OR = 2.06, 95% CI: 1.32–3.20) and heavy drinkers (OR = 2.00, 95% CI: 1.28–3.09) for G allele carriers. This meta-analysis suggests that the MTR A2756G polymorphism is not associated with CRC/CRA susceptibility and that gene-environment interaction may exist. PMID:23593229

Association between F508 deletion in CFTR and chronic pancreatitis risk.

PubMed

Zhao, Dong; Xu, Yanzhen; Li, Jiatong; Fu, Shien; Xiao, Feifan; Song, Xiaowei; Xie, Zhibin; Jiang, Min; He, Yan; Liu, Chengwu; Wen, Qiongxian; Yang, Xiaoli

2017-09-01

The cystic fibrosis transmembrane conductance regulator (CFTR) has been reported to influence individual susceptibility to chronic pancreatitis (CP), but the results of previous studies are controversial. We performed a study to demonstrate the relationship between CFTR and CP. We searched PubMed, Scopus, and Embase for studies of patients with CP. Seven studies from 1995 to 2016 were identified, and included 64,832 patients. Pooled prevalence and 95% confidence intervals (CIs) were calculated. F508 deletion in CFTR was significantly positively associated with CP risk in the overall analysis (odds ratio [OR]=3.20, 95% CI: 2.30-4.44, I 2 =31.7%). In subgroup analysis stratified by ethnicity, F508 deletion was significantly associated with CP risk in Indian populations, using a fixed effects model (ORs=5.45, 95% CI: 2.52-11.79, I 2 =0.0%), and in non-Indian populations, using a random effects model (ORs=3.59, 95% CI: 1.73-7.48, I 2 =60.9%). At the same time, we found that Indians with F508 deletion had much higher CP prevalence than non-Indians. Interestingly, F508 deletion was also associated with CP and idiopathic CP risk in subgroup analysis stratified by aeitiology, using the fixed effects model. Based on current evidence, F508 deletion is a risk factor for CP, and Indians with F508 deletion have much higher CP morbidity. Copyright © 2017 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.

Factors Associated With Inadequate Effectiveness of a Multidisciplinary Disease Management Program in Heart Failure Patients Stratified by Galectin 3 Level.

PubMed

Liu, Min-Hui; Wang, Chao-Hung; Chiou, Ai-Fu; Yang, Ning-I; Kuo, Li-Tang

2016-07-21

This study investigated whether multidisciplinary disease management programs (MDPs) exert the same effects in heart failure (HF) patients across risk levels stratified by galectin-3 (Gal-3) level and what factors are associated with inadequate effectiveness of MDP. We used a longitudinal follow-up design based on a previous randomized trial. A total of 355 stabilized hospitalized HF patients were enrolled. The effects of MDP on death and HF-related rehospitalization were analyzed according to Gal-3 levels. During the 4-year follow-up, Gal-3 levels predicted mortality and composite events (p < .001). Multivariable analysis demonstrated the event-lowering effect of MDP (hazard ratio [HR] = 0.49, p = .001 for death and HR = 0.50, p < .001 for composite events). However, the effect of MDP was inadequate for those with high Gal-3 levels (≥17.9 ng/ml), whose 4-year composite event rate was 43% in the MDP arm. Further analysis showed that, in patients with Gal-3 ≥ 17.9 ng/ml, the independent factors associated with a high composite event rate were no MDP, older age, worse New York Heart Association functional class, no angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker use, higher predischarge natriuretic peptide levels, and wider QRS complexes. The effectiveness of MDP for HF patients at high risk was inadequate. Our findings identified the characteristics of these MDP nonresponders. Better integration of advanced care plans based on strategies guided by Gal-3 level is needed to improve care quality. © The Author(s) 2016.

Comparison of the risk factors effects between two populations: two alternative approaches illustrated by the analysis of first and second kidney transplant recipients

PubMed Central

2013-01-01

Background Whereas the prognosis of second kidney transplant recipients (STR) compared to the first ones has been frequently analyzed, no study has addressed the issue of comparing the risk factor effects on graft failure between both groups. Methods Here, we propose two alternative strategies to study the heterogeneity of risk factors between two groups of patients: (i) a multiplicative-regression model for relative survival (MRS) and (ii) a stratified Cox model (SCM) specifying the graft rank as strata and assuming subvectors of the explicatives variables. These developments were motivated by the analysis of factors associated with time to graft failure (return-to-dialysis or patient death) in second kidney transplant recipients (STR) compared to the first ones. Estimation of the parameters was based on partial likelihood maximization. Monte-Carlo simulations associated with bootstrap re-sampling was performed to calculate the standard deviations for the MRS. Results We demonstrate, for the first time in renal transplantation, that: (i) male donor gender is a specific risk factor for STR, (ii) the adverse effect of recipient age is enhanced for STR and (iii) the graft failure risk related to donor age is attenuated for STR. Conclusion While the traditional Cox model did not provide original results based on the renal transplantation literature, the proposed relative and stratified models revealed new findings that are useful for clinicians. These methodologies may be of interest in other medical fields when the principal objective is the comparison of risk factors between two populations. PMID:23915191

Turbulent Heat Transfer from a Thermally Forced Boundary in a Stratified Fluid

NASA Astrophysics Data System (ADS)

Burns, K. J.; Wells, A.; Flierl, G.

2017-12-01

When a marine-terminating glacier melts into a stratified ocean, a buoyancy-driven flow develops along the ice surface. The resulting turbulent heat and salt fluxes provide a key feedback on the ice melting rate. To build insight into such flows, we consider direct numerical simulations of an analogue problem with convection driven by a thermally forced sidewall in a stably stratified Boussinesq fluid. Our model considers vertical and inclined periodic channels in 2D with a constant background buoyancy gradient. When the lateral or upper boundary is given a sufficient thermal perturbation relative to the ambient, a confined and homogeneous turbulent plume emerges along the heated wall. We present a scaling analysis for the resulting heat transport across the plume, and compare it to simulations over a range of Rayleigh numbers, Prandtl numbers, and wall-inclination angles.

Pro-Active Fall-Risk Management is Mandatory to Sustain in Hospital-Fall Prevention in Older Patients--Validation of the LUCAS Fall-Risk Screening in 2,337 Patients.

PubMed

Hoffmann, V S; Neumann, L; Golgert, S; von Renteln-Kruse, W

2015-12-01

Prevention of in-hospital falls contributes to improvement of patient safety. However, the identification of high-risk patients remains a challenge despite knowledge of fall-risk factors. Hence, objective was to prospectively validate the performance of the LUCAS (Longitudinal Urban Cohort Ageing Study) fall-risk screening, based on routine data (fall history, mobility, mental status) and applied by nurses. Observational study comparing two groups of patients who underwent different fall-risk screenings; the LUCAS screening (2010 - 2011) and the STRATIFY (St. Thomas's Risk Assessment Tool In Falling Elderly Inpatients) (2004 - 2006). Urban teaching hospital. Consecutively hospitalized patients (≥ 65 years old) were screened on admission; LUCAS n = 2,337, STRATIFY n = 4,735. The proportions of fallers were compared between the STRATIFY and the LUCAS time periods. The number of fallers expected was compared to that observed in the LUCAS time period. Standardized fall-incidence recording included case-note checks for unreported falls. Plausibility checks of fall-risk factors and logistic regression analysis for variable fall-risk factors were performed. The proportions of fallers during the two time periods were LUCAS n = 291/2,337 (12.5%) vs. STRATIFY n = 508/4,735 (10.7%). After adjustment for risk-factor prevalence, the proportion of fallers expected was 14.5% (334/2,337), the proportion observed was 12.5% (291/2,337) (p = 0.038). In-hospital fall prevention including systematic use of the LUCAS fall-risk screening reduced the proportion of fallers compared to that expected from the patients' fall-risk profile. Raw proportions of fallers are not suitable to evaluate fall prevention in hospital because of variable prevalence of patients' fall-risk factors over time. Continuous communication, education and training is needed to sustain in-hospital falls prevention.

3D architecture of cyclic-step and antidune deposits in glacigenic subaqueous fan and delta settings: Integrating outcrop and ground-penetrating radar data

NASA Astrophysics Data System (ADS)

Lang, Jörg; Sievers, Julian; Loewer, Markus; Igel, Jan; Winsemann, Jutta

2017-12-01

Bedforms related to supercritical flows are increasingly recognised as important constituents of many depositional environments, but outcrop studies are commonly hampered by long bedform wavelengths and complex three-dimensional geometries. We combined outcrop-based facies analysis with ground-penetrating radar (GPR) surveys to analyse the 3D facies architecture of subaqueous ice-contact fan and glacifluvial delta deposits. The studied sedimentary systems were deposited at the margins of the Middle Pleistocene Scandinavian ice sheets in Northern Germany. Glacifluvial Gilbert-type deltas are characterised by steeply dipping foreset beds, comprising cyclic-step deposits, which alternate with antidune deposits. Deposits of cyclic steps consist of lenticular scours infilled by backset cross-stratified pebbly sand and gravel. The GPR sections show that the scour fills form trains along the delta foresets, which can locally be traced for up to 15 m. Perpendicular and oblique to palaeoflow direction, these deposits appear as troughs with concentric or low-angle cross-stratified infills. Downflow transitions from scour fills into sheet-like low-angle cross-stratified or sinusoidally stratified pebbly sand, deposited by antidunes, are common. Cyclic steps and antidunes were deposited by sustained and surge-type supercritical density flows, which were related to hyperpycnal flows, triggered by major meltwater discharge or slope-failure events. Subaqueous ice-contact fan deposits include deposits of progradational scour fills, isolated hydraulic jumps, antidunes and (humpback) dunes. The gravel-rich fan succession consists of vertical stacks of laterally amalgamated pseudo-sheets, indicating deposition by pulses of waning supercritical flows under high aggradation rates. The GPR sections reveal the large-scale architecture of the sand-rich fan succession, which is characterised by lobe elements with basal erosional surfaces associated with scours filled with backsets related to hydraulic jumps, passing upwards and downflow into deposits of antidunes and (humpback) dunes. The recurrent facies architecture of the lobe elements and their prograding and retrograding stacking pattern are interpreted as related to autogenic flow morphodynamics.

XPA A23G polymorphism and risk of digestive system cancers: a meta-analysis.

PubMed

He, Lei; Deng, Tao; Luo, Hesheng

2015-01-01

Several studies have reported an association between the A23G polymorphism (rs 1800975) in the xeroderma pigmentosum group A (XPA) gene and risk of digestive system cancers. However, the results are inconsistent. In this study, we performed a meta-analysis to assess the association between XPA A23G polymorphism and the risk of digestive system cancers. Relevant studies were identified using the PubMed, Web of Science, China National Knowledge Infrastructure, WanFang, and VIP databases up to August 30, 2014. The pooled odds ratio (OR) with a 95% confidence interval (CI) was calculated using the fixed or random effects model. A total of 18 case-control studies from 16 publications with 4,170 patients and 6,929 controls were included. Overall, no significant association was found between XPA A23G polymorphism and the risk of digestive system cancers (dominant model: GA + AA versus GG, OR 0.89, 95% CI 0.74-1.08; recessive model: AA versus GA + GG, OR 0.94, 95% CI 0.74-1.20; GA versus GG, OR 0.89, 95% CI 0.77-1.03; and AA versus GG, OR 0.87, 95% CI 0.64-1.19). When the analysis was stratified by ethnicity, similar results were observed among Asians and Caucasians in all genetic models. In stratified analysis based on tumor type, we also failed to detect any association between XPA A23G polymorphism and the risk of esophageal, gastric, or colorectal cancers. This meta-analysis indicates that the XPA A23G polymorphism is not associated with a risk of digestive system cancers.

A software suite for the generation and comparison of peptide arrays from sets of data collected by liquid chromatography-mass spectrometry.

PubMed

Li, Xiao-jun; Yi, Eugene C; Kemp, Christopher J; Zhang, Hui; Aebersold, Ruedi

2005-09-01

There is an increasing interest in the quantitative proteomic measurement of the protein contents of substantially similar biological samples, e.g. for the analysis of cellular response to perturbations over time or for the discovery of protein biomarkers from clinical samples. Technical limitations of current proteomic platforms such as limited reproducibility and low throughput make this a challenging task. A new LC-MS-based platform is able to generate complex peptide patterns from the analysis of proteolyzed protein samples at high throughput and represents a promising approach for quantitative proteomics. A crucial component of the LC-MS approach is the accurate evaluation of the abundance of detected peptides over many samples and the identification of peptide features that can stratify samples with respect to their genetic, physiological, or environmental origins. We present here a new software suite, SpecArray, that generates a peptide versus sample array from a set of LC-MS data. A peptide array stores the relative abundance of thousands of peptide features in many samples and is in a format identical to that of a gene expression microarray. A peptide array can be subjected to an unsupervised clustering analysis to stratify samples or to a discriminant analysis to identify discriminatory peptide features. We applied the SpecArray to analyze two sets of LC-MS data: one was from four repeat LC-MS analyses of the same glycopeptide sample, and another was from LC-MS analysis of serum samples of five male and five female mice. We demonstrate through these two study cases that the SpecArray software suite can serve as an effective software platform in the LC-MS approach for quantitative proteomics.

Lithofacies and seismic-reflection interpretation of temperate glacimarine sedimentation in Tarr Inlet, Glacier Bay, Alaska

USGS Publications Warehouse

Cai, J.; Powell, R.D.; Cowan, E.A.; Carlson, P.R.

1997-01-01

High-resolution seismic-reflection profiles of sediment fill within Tart Inlet of Glacier Bay, Alaska, show seismic facies changes with increasing distance from the glacial termini. Five types of seismic facies are recognized from analysis of Huntec and minisparker records, and seven lithofacies are determined from detailed sedimentologic study of gravity-, vibro- and box-cores, and bottom grab samples. Lithofacies and seismic facies associations, and fjord-floor morphology allow us to divide the fjord into three sedimentary environments: ice-proximal, iceberg-zone and ice-distal. The ice-proximal environment, characterized by a morainal-bank depositional system, can be subdivided into bank-back, bank-core and bank-front subenvironments, each of which is characterized by a different depositional subsystem. A bank-back subsystem shows chaotic seismic facies with a mounded surface, which we infer consists mainly of unsorted diamicton and poorly sorted coarse-grained sediments. A bank-core depositional subsystem is a mixture of diamicton, rubble, gravel, sand and mud. Seismic-reflection records of this subsystem are characterized by chaotic seismic facies with abundant hyperbolic diffractions and a hummocky surface. A bank-front depositional subsystem consists of mainly stratified and massive sand, and is characterized by internal hummocky facies on seismic-reflection records with significant surface relief and sediment gravity flow channels. The depositional system formed in the iceberg-zone environment consists of rhythmically laminated mud interbedded with thin beds of weakly stratified diamicton and stratified or massive sand and silt. On seismic-reflection profiles, this depositional system is characterized by discontinuously stratified facies with multiple channels on the surface in the proximal zone and a single channel on the largely flat sediment surface in the distal zone. The depositional system formed in the ice-distal environment consists of interbedded homogeneous or laminated mud and massive or stratified sand and coarse silt. This depositional system shows continuously stratified seismic facies with smooth and flat surfaces on minisparker records, and continuously stratified seismic facies which are interlayered with thin weakly stratified facies on Huntec records.

Using known map category marginal frequencies to improve estimates of thematic map accuracy

NASA Technical Reports Server (NTRS)

Card, D. H.

1982-01-01

By means of two simple sampling plans suggested in the accuracy-assessment literature, it is shown how one can use knowledge of map-category relative sizes to improve estimates of various probabilities. The fact that maximum likelihood estimates of cell probabilities for the simple random sampling and map category-stratified sampling were identical has permitted a unified treatment of the contingency-table analysis. A rigorous analysis of the effect of sampling independently within map categories is made possible by results for the stratified case. It is noted that such matters as optimal sample size selection for the achievement of a desired level of precision in various estimators are irrelevant, since the estimators derived are valid irrespective of how sample sizes are chosen.

The influence of IQ stratification on WAIS-III/WMS-III FSIQ-general memory index discrepancy base-rates in the standardization sample.

PubMed

Hawkins, K A; Tulsky, D S

2001-11-01

Since memory performance expectations may be IQ-based, unidirectional base rate data for IQ-Memory Score discrepancies are provided in the WAIS-III/WMS-III Technical Manual. The utility of these data partially rests on the assumption that discrepancy base rates do not vary across ability levels. FSIQ stratified base rate data generated from the standardization sample, however, demonstrate substantial variability across the IQ spectrum. A superiority of memory score over FSIQ is typical at lower IQ levels, whereas the converse is true at higher IQ levels. These data indicate that the use of IQ-memory score unstratified "simple difference" tables could lead to erroneous conclusions for clients with low or high IQ. IQ stratified standardization base rate data are provided as a complement to the "predicted difference" method detailed in the Technical Manual.

Entrainment-Zone Restratification and Flow Structures in Stratified Shear Turbulence

NASA Technical Reports Server (NTRS)

Reif, B. Anders Pettersson; Werne, Joseph; Andreassen, Oyvind; Meyer, Christian; Davis-Mansour, Melissa

2002-01-01

Late-time dynamics and morphology of a stratified turbulent shear layer are examined using 1) Reynolds-stress and heat-flux budgets, 2) the single-point structure tensors introduced by Kassinos et al. (2001), and 3) flow visualization via 3D volume rendering. Flux reversal is observed during restratification in the edges of the turbulent layer. We present a first attempt to quantify the turbulence-mean-flow interaction and to characterize the predominant flow structures. Future work will extend this analysis to earlier times and different values of the Reynolds and Richardson numbers.

Association of arsenobetaine with beta-cell function assessed by homeostasis model assessment (HOMA) in nondiabetic Koreans: data from the fourth Korea National Health and Nutrition Examination Survey (KNHANES) 2008-2009.

PubMed

Baek, Kiook; Lee, Namhoon; Chung, Insung

2017-01-01

Arsenic is known as an endocrine disruptor that people are exposed to through various sources such as drinking water and indigestion of marine products. Although some epidemiological and animal studies have reported a correlation between arsenic exposure and diabetes development, there are limited studies regarding the toxic effects of organic arsenic including arsenobetaine on the human body. Here, we analyzed the association between urine arsenobetaine and the homeostasis model assessment of β-cell function (HOMA-β), which is an index for predicting diabetes development and reflecting the function of pancreatic β-cells. In the fourth Korea National Health and Nutrition Examination Survey (KNHANES), health and nutrition surveys and screening tests were performed. Of the total survey population, people with confirmed values for urine total arsenic and arsenobetaine were included, and known diabetic patients were excluded. A total 369 participants were finally included in the study. We collected surveys on health, height, body weight, body mass index, blood mercury level, fasting glucose level, and serum insulin level and calculated HOMA index. Owing to sexual discrepancy, we performed sexually stratified analysis. Urine total arsenic and total arsenic minus arsenobetaine was not associated with HOMA-IR and HOMA-β in univariate analysis or in sexually stratified analysis. However, urine arsenobetaine showed a statistically significant relationship with HOMA-β in univariate analysis, and only male participants showed a significant correlation in sexually stratified analysis. In the analysis adjusted for age, BMI, smoking, alcohol drinking, physical activity and blood mercury, the HOMA-β value in the group below the 25th percentile of arsenobetaine was significantly higher than the group between 50 and 75th percentile, while no difference was shown for HOMA-IR. In sexually stratified analysis, The value of HOMA-β was significantly higher in male participants with below the 25th percentile urine arsenobetaine than the group between 25 and 50th and between 50 and 75th, while no difference was shown for HOMA-IR. However, female participants did not demonstrate a relationship between HOMA-IR, HOMA-β and urine arsenobetaine. This study revealed the association between urine arsenobetaine and pancreatic β-cell function assessed by HOMA-β in the normal population (without diabetes), especially in males, despite adjusting for factors affecting pancreatic β-cell function and diabetes.

Convergence acceleration of computer methods for grounding analysis in stratified soils

NASA Astrophysics Data System (ADS)

Colominas, I.; París, J.; Navarrina, F.; Casteleiro, M.

2010-06-01

The design of safe grounding systems in electrical installations is essential to assure the protection of the equipment, the power supply continuity and the security of the persons. In order to achieve these goals, it is necessary to compute the equivalent electrical resistance of the system and the potential distribution on the earth surface when a fault condition occurs. In the last years the authors have developed a numerical formulation based on the BEM for the analysis of grounding systems embedded in uniform and layered soils. As it is known, in practical cases the underlying series have a poor rate of convergence and the use of multilayer soils requires an out of range computational cost. In this paper we present an efficient technique based on the Aitken δ2-process in order to improve the rate of convergence of the involved series expansions.

Stratified turbulent Bunsen flames: flame surface analysis and flame surface density modelling

NASA Astrophysics Data System (ADS)

Ramaekers, W. J. S.; van Oijen, J. A.; de Goey, L. P. H.

2012-12-01

In this paper it is investigated whether the Flame Surface Density (FSD) model, developed for turbulent premixed combustion, is also applicable to stratified flames. Direct Numerical Simulations (DNS) of turbulent stratified Bunsen flames have been carried out, using the Flamelet Generated Manifold (FGM) reduction method for reaction kinetics. Before examining the suitability of the FSD model, flame surfaces are characterized in terms of thickness, curvature and stratification. All flames are in the Thin Reaction Zones regime, and the maximum equivalence ratio range covers 0.1⩽φ⩽1.3. For all flames, local flame thicknesses correspond very well to those observed in stretchless, steady premixed flamelets. Extracted curvature radii and mixing length scales are significantly larger than the flame thickness, implying that the stratified flames all burn in a premixed mode. The remaining challenge is accounting for the large variation in (subfilter) mass burning rate. In this contribution, the FSD model is proven to be applicable for Large Eddy Simulations (LES) of stratified flames for the equivalence ratio range 0.1⩽φ⩽1.3. Subfilter mass burning rate variations are taken into account by a subfilter Probability Density Function (PDF) for the mixture fraction, on which the mass burning rate directly depends. A priori analysis point out that for small stratifications (0.4⩽φ⩽1.0), the replacement of the subfilter PDF (obtained from DNS data) by the corresponding Dirac function is appropriate. Integration of the Dirac function with the mass burning rate m=m(φ), can then adequately model the filtered mass burning rate obtained from filtered DNS data. For a larger stratification (0.1⩽φ⩽1.3), and filter widths up to ten flame thicknesses, a β-function for the subfilter PDF yields substantially better predictions than a Dirac function. Finally, inclusion of a simple algebraic model for the FSD resulted only in small additional deviations from DNS data, thereby rendering this approach promising for application in LES.

Frequency of distracting tasks people do while driving : an analysis of the ACAS FOT data.

DOT National Transportation Integrated Search

2007-06-01

This report describes further analysis of data from the advanced collision avoidance system (ACAS) field operational test, a naturalistic driving study. To determine how distracted and nondistracted driving differ, a stratified sample of 2,914 video ...

Monitoring land cover changes by remote sensing in north west Egypt

NASA Astrophysics Data System (ADS)

Richards, Timothy Steven

The Mediterratiean coastal strip of Egypt is a semi-arid environment which supports a variety of agricultural practices ranging from irrigated sedentary agriculture to semi-nomadic pastoralism. The sedentarisation of the nomadic Bedouin coupled with an increase in population of both people and livestock and a decrease in the extent of the rangelands, has resulted in severe pressure being exerted upon the environment. Satellite remote sensing of vegetation offers the potential to aid regional management by complementing conventional techniques of vegetation mapping and monitoring. This thesis examines the different techniques available for vegetation mapping using visible and near infrared spectral wave bands. The different techniques available for vegetation mapping using remotely sensed data are reviewed and discussed with reference to semi-arid environments. The underlying similarity of many of the techniques is emphasised and their individual merits discussed. The spectral feature-space of Landsat data of two representative study areas in northern Egypt is explored and examined using graphical techniques and principal components analysis. Hand held radiometric field data are also presented for individual soil types within the region. It is proposed that by using reference data for individual soil types, improved estimates of vegetation cover can be ascertained. A number of radiometric corrections are applied to the digital Landsat data in order to convert the arbitrary digital values of the different spectral bands into physical values of reflectance. The effect of this standardization on the principal components is examined. The stratified approach to vegetation mapping which was explored using the field data is applied in turn to the digital Landsat images. Whilst the stratified approach was not found to offer significant advantages over the non-stratified approach in this case, the analysis does serve to provide an accurate datum against which to measure vegetation. In conclusion a satellite based system for operational vegetation monitoring is proposed.

Electrocardiographic Findings in Brazilian Adults without Heart Disease: ELSA-Brasil.

PubMed

Pinto, Marcelo Martins; Brant, Luisa C C; Padilha-da-Silva, José Luiz; Foppa, Murilo; Lotufo, Paulo A; Mill, José Geraldo; Vasconcelo-Silva, Paulo R; Almeida, Maria da Conceição C; Barreto, Sandhi Maria; Ribeiro, Antônio Luiz Pinho

2017-11-01

The electrocardiogram (ECG) is widely used in population-based studies. However, there are few studies on electrocardiographic findings in Latin America and in Brazil. The Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) comprised 15,105 participants (35-74 years) from six Brazilian capitals. To describe electrocardiographic findings in Brazilian adults without heart disease, stratified by sex, age and race/skin color. Cross-sectional study with baseline data of 11,094 adults (44.5% men) without heart disease from ELSA-Brasil. The ECGs were recorded with the Burdick Atria 6100 machine and stored at the Pyramis System. ECG analysis was automatically performed using the Glasgow University software. A descriptive analysis of heart rate (HR), P, QRS and T waves' duration, PR and QT intervals, and P, R and T axes was performed. After stratification by sex, race/color and age, the groups were compared by the Wilcoxon and Kruskal-Wallis test at a significance level of 5%. Linear regression models were used to evaluate the behavior of electrocardiographic parameters over age. Major electrocardiographic abnormalities defined by the Minnesota code were manually revised. Medians values of the electrocardiographic parameters were different between men and women: HR 63 vs. 66 bpm, PR 164 vs.158 ms, QT corrected 410 vs. 421 ms, QRS duration 92 vs. 86 ms, P-wave duration 112 vs. 108 ms, P-wave axis 54 vs. 57 degrees, R-wave axis 35 vs. 39 degrees, T-wave axis 39 vs. 45 degrees (p < 0.001 for all). The 2nd and the 98th percentiles of each variable were also obtained, and graphs were constructed to illustrate the behavior of the electrocardiographic findings over age of participants stratified by sex and race/skin color. The values for the electrocardiographic measurements herein described can be used as reference for Brazilian adults free of heart disease, stratified by sex. Our results suggest that self-reported race/skin color have no significant influence on electrocardiographic parameters.

Electrocardiographic Findings in Brazilian Adults without Heart Disease: ELSA-Brasil

PubMed Central

Pinto Filho, Marcelo Martins; Brant, Luisa C. C.; Padilha-da-Silva, José Luiz; Foppa, Murilo; Lotufo, Paulo A.; Mill, José Geraldo; Vasconcelo-Silva, Paulo R.; Almeida, Maria da Conceição C.; Barreto, Sandhi Maria; Ribeiro, Antônio Luiz Pinho

2017-01-01

Background The electrocardiogram (ECG) is widely used in population-based studies. However, there are few studies on electrocardiographic findings in Latin America and in Brazil. The Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) comprised 15,105 participants (35-74 years) from six Brazilian capitals. Objectives To describe electrocardiographic findings in Brazilian adults without heart disease, stratified by sex, age and race/skin color. Methods Cross-sectional study with baseline data of 11,094 adults (44.5% men) without heart disease from ELSA-Brasil. The ECGs were recorded with the Burdick Atria 6100 machine and stored at the Pyramis System. ECG analysis was automatically performed using the Glasgow University software. A descriptive analysis of heart rate (HR), P, QRS and T waves’ duration, PR and QT intervals, and P, R and T axes was performed. After stratification by sex, race/color and age, the groups were compared by the Wilcoxon and Kruskal-Wallis test at a significance level of 5%. Linear regression models were used to evaluate the behavior of electrocardiographic parameters over age. Major electrocardiographic abnormalities defined by the Minnesota code were manually revised. Results Medians values of the electrocardiographic parameters were different between men and women: HR 63 vs. 66 bpm, PR 164 vs.158 ms, QT corrected 410 vs. 421 ms, QRS duration 92 vs. 86 ms, P-wave duration 112 vs. 108 ms, P-wave axis 54 vs. 57 degrees, R-wave axis 35 vs. 39 degrees, T-wave axis 39 vs. 45 degrees (p < 0.001 for all). The 2nd and the 98th percentiles of each variable were also obtained, and graphs were constructed to illustrate the behavior of the electrocardiographic findings over age of participants stratified by sex and race/skin color. Conclusions The values for the electrocardiographic measurements herein described can be used as reference for Brazilian adults free of heart disease, stratified by sex. Our results suggest that self-reported race/skin color have no significant influence on electrocardiographic parameters. PMID:28977056

A radiative transfer model for microwave emissions from bare agricultural soils

NASA Technical Reports Server (NTRS)

Burke, W. J.; Paris, J. F.

1975-01-01

A radiative transfer model for microwave emissions from bare, stratified agricultural soils was developed to assist in the analysis of data gathered in the joint soil moisture experiment. The predictions of the model were compared with preliminary X band (2.8 cm) microwave and ground based observations. Measured brightness temperatures at vertical and horizontal polarizations can be used to estimate the moisture content of the top centimeter of soil with + or - 1 percent accuracy. It is also shown that the Stokes parameters can be used to distinguish between moisture and surface roughness effects.

Adiabatic Wankel type rotary engine

NASA Technical Reports Server (NTRS)

Kamo, R.; Badgley, P.; Doup, D.

1988-01-01

This SBIR Phase program accomplished the objective of advancing the technology of the Wankel type rotary engine for aircraft applications through the use of adiabatic engine technology. Based on the results of this program, technology is in place to provide a rotor and side and intermediate housings with thermal barrier coatings. A detailed cycle analysis of the NASA 1007R Direct Injection Stratified Charge (DISC) rotary engine was performed which concluded that applying thermal barrier coatings to the rotor should be successful and that it was unlikely that the rotor housing could be successfully run with thermal barrier coatings as the thermal stresses were extensive.

Quantifying factors for the success of stratified medicine.

PubMed

Trusheim, Mark R; Burgess, Breon; Hu, Sean Xinghua; Long, Theresa; Averbuch, Steven D; Flynn, Aiden A; Lieftucht, Alfons; Mazumder, Abhijit; Milloy, Judy; Shaw, Peter M; Swank, David; Wang, Jian; Berndt, Ernst R; Goodsaid, Federico; Palmer, Michael C

2011-10-31

Co-developing a drug with a diagnostic to create a stratified medicine - a therapy that is targeted to a specific patient population on the basis of a clinical characteristic such as a biomarker that predicts treatment response - presents challenges for product developers, regulators, payers and physicians. With the aim of developing a shared framework and tools for addressing these challenges, here we present an analysis using data from case studies in oncology and Alzheimer's disease, coupled with integrated computational modelling of clinical outcomes and developer economic value, to quantify the effects of decisions related to key issues such as the design of clinical trials. This illustrates how such analyses can aid the coordination of diagnostic and drug development, and the selection of optimal development and commercialization strategies. It also illustrates the impact of the interplay of these factors on the economic feasibility of stratified medicine, which has important implications for public policy makers.

Embodied innovation and regulation of medical technoscience: transformations in cancer patienthood

PubMed Central

Kerr, Anne; Cunningham-Burley, Sarah

2015-01-01

ABSTRACT Biomedical advances are transforming the diagnosis and treatment of disease. Patienthood is also transforming, as patients actively participate in research, innovation and regulation of novel technologies and therapies. In this paper we explore the new kinds of practices that patients are performing in their roles as research subject, co-researchers, donors, campaigners, representatives and consumers of novel stratified therapies. We outline their embodied contributions to clinical trials, biobanks and stratified therapies prior to, during and after having cancer. Exploring how patienthood involves donating more than tissue or data to these developments, we consider their emotional and identity work which informs and shapes the novel diagnostics and therapies being developed. We also consider how this kind of work is stratified according to the social and biological location of participants, and end by reflecting on the implications of our analysis for the organisation and regulation of biomedicine. PMID:27996062

Parametric instability and wave turbulence driven by tidal excitation of internal waves

NASA Astrophysics Data System (ADS)

Le Reun, Thomas; Favier, Benjamin; Le Bars, Michael

2018-04-01

We investigate the stability of stratified fluid layers undergoing homogeneous and periodic tidal deformation. We first introduce a local model which allows to study velocity and buoyancy fluctuations in a Lagrangian domain periodically stretched and sheared by the tidal base flow. While keeping the key physical ingredients only, such a model is efficient to simulate planetary regimes where tidal amplitudes and dissipation are small. With this model, we prove that tidal flows are able to drive parametric subharmonic resonances of internal waves, in a way reminiscent of the elliptical instability in rotating fluids. The growth rates computed via Direct Numerical Simulations (DNS) are in very good agreement with WKB analysis and Floquet theory. We also investigate the turbulence driven by this instability mechanism. With spatio-temporal analysis, we show that it is a weak internal wave turbulence occurring at small Froude and buoyancy Reynolds numbers. When the gap between the excitation and the Brunt-V\\"ais\\"al\\"a frequencies is increased, the frequency spectrum of this wave turbulence displays a -2 power law reminiscent of the high-frequency branch of the Garett and Munk spectrum (Garrett & Munk 1979) which has been measured in the oceans. In addition, we find that the mixing efficiency is altered compared to what is computed in the context of DNS of stratified turbulence excited at small Froude and large buoyancy Reynolds numbers and is consistent with a superposition of waves.

On comparison of net survival curves.

PubMed

Pavlič, Klemen; Perme, Maja Pohar

2017-05-02

Relative survival analysis is a subfield of survival analysis where competing risks data are observed, but the causes of death are unknown. A first step in the analysis of such data is usually the estimation of a net survival curve, possibly followed by regression modelling. Recently, a log-rank type test for comparison of net survival curves has been introduced and the goal of this paper is to explore its properties and put this methodological advance into the context of the field. We build on the association between the log-rank test and the univariate or stratified Cox model and show the analogy in the relative survival setting. We study the properties of the methods using both the theoretical arguments as well as simulations. We provide an R function to enable practical usage of the log-rank type test. Both the log-rank type test and its model alternatives perform satisfactory under the null, even if the correlation between their p-values is rather low, implying that both approaches cannot be used simultaneously. The stratified version has a higher power in case of non-homogeneous hazards, but also carries a different interpretation. The log-rank type test and its stratified version can be interpreted in the same way as the results of an analogous semi-parametric additive regression model despite the fact that no direct theoretical link can be established between the test statistics.

A numerical procedure for solving the inverse scattering problem for stratified dielectric media

NASA Astrophysics Data System (ADS)

Vogelzang, E.; Yevick, D.; Ferwerda, H. A.

1983-05-01

In this paper the refractive index profile of a dielectric stratified medium, terminated by a perfect conductor, is calculated from the complex reflection coefficient for monochromatic plane waves, incident from different directions. The advantage of this approach is that the dispersion of the refractive index does not enter the calculations. The calculation is based on the Marchenko and Gelfand-Levitan equations taking into account the bound modes of the layer. Some illustrative numerical examples are presented.

Water resources of the New Jersey part of the Ramapo River basin

USGS Publications Warehouse

Vecchioli, John; Miller, E.G.

1973-01-01

The Ramapo River, a major stream in the Passaic River basin, drains an area of 161 square miles, 70 percent of which is in Orange and Rockland Counties, N.Y., and 30 percent is in Bergen and Passaic Counties, N.J. This report describes the hydrology of the New Jersey part of the basin and evaluates the feasibility of developing large ground-water supplies from the stratified drift in the Ramapo River valley by inducing recharge to the aquifer from the river. The ground water and surface water of the basin are considered as a single resource because the development of either ground water or surface water affects the availability of the other. Precambrian gneiss, sparsely mantled with Pleistocene glacial drift, underlies the basin west of the Ramapo River in New Jersey. To the east, bedrock consists of the Watchung Basalt and of shale, sandstone, and conglomerate of the Brunswick Formation of Triassic age. Glacial drift occurs nearly everywhere in the eastern part of the basin, and deposits of stratified drift more than 100 feet thick occur in the Ramapo valley. Average annual runoff at Pompton Lakes accounts for 25 inches of the 45 inches of annual precipitation in the New Jersey part of the basin, and the remaining 20 inches is accounted for by evapotranspiration. Streamflow is highly variable--particularly in the area underlain by gneissic rocks-because of the low storage capacity of the rocks and the rough topography. Many of the small tributaries go dry during extended periods of no precipitation. Small domestic supplies of ground water can be obtained nearly everywhere, but the Brunswick Formation is the only consolidated-rock aquifer in the basin that can be depended upon to yield 100-200 gallons per minute to wells. Supplies of more than 1,000 gallons per minute are available from wells tapping the stratified drift in the Ramapo valley. The drift supplies 75 percent of the ground water pumped for public supply in the basin. Sustained ground-water yield in upland areas, based on stream base-flow recession, is estimated to be 200,000-300,000 gallons per day per square mile for the drift-covered Brunswick Formation and about 100,000-200,000 gallons per day per square mile for the gneiss and basalt. Potential sustained yield of the stratified drift in the valley depends on the availability of the streamflow and on the induced rate of infiltration. Pumping from the stratified drift results in a reduction in streamflow, which may be undesirable, mainly because of prior downstream water rights. On the basis of the storage available in the stratified drift and an analysis of daily flow during the drought period of October 1964 to September 1967 at Pompton Lakes, 20-25 million gallons per day of Ramapo River water are available for development after existing downstream water requirements are supplied. However, some low-flow augmentation will be. necessary to insure downstream rights. Rates of infiltration computed from seepage losses observed near Mahwah indicate that at least 11 million gallons per day, on an average basis, can be infiltrated from the river by the pumping of wells tapping the stratified drift. The use of recharge pits and spreading areas would increase the rate of infiltration. Losses from the Ramapo River could be minimized by returning treated sewage effluent directly to the river or, preferably, by recharging the stratified-drift aquifer with the treated effluent. Ground-water quality and surface-water quality at times of low-flow vary according to the type of rock from which the water is obtained. Water from the gneiss is low in dissolved solids--less than 127 mg/l (milligrams per liter)--and soft to moderately hard--less than 94 rag/l. Water from the Brunswick Formation is more mineralized--total dissolved-solids content is as much as 278 mg/1 and hardness as much as 188 mg/1. Water from the stratified drift is generally intermediate in quality--that is, total dissolved-solids content is as

Flow dynamics and salt transport in a coastal aquifer driven by a stratified saltwater body: Lab experiment and numerical modeling

NASA Astrophysics Data System (ADS)

Oz, Imri; Shalev, Eyal; Yechieli, Yoseph; Gavrieli, Ittai; Gvirtzman, Haim

2014-04-01

This paper examines the transient development and the steady-state configuration of groundwater within a coastal aquifer adjacent to a stratified saltwater body. Such systems consist of three different water types: the regional fresh groundwater, and low and high salinity brines forming the upper and lower water layers of the stratified water body, respectively. The dynamics, location and the geometry of the interfaces and the density-driven circulation flows that develop in the aquifer are examined using laboratory experiments and numerical modeling at the same scale. The results show that the transient intrusion of the different water bodies into the aquifer takes place at different rates, and that the locations of the interfaces between them change with time, before reaching steady-state. Under steady-state conditions both the model and the experiments show the existence of three interfaces between the three water types. The numerical model, which is calibrated against the salinity distribution and groundwater discharge rate in the laboratory experiments, allows the quantification of the flow rates and flow patterns within the aquifer. These flow patterns, which cannot be derived from laboratory experiments, show the transient development of three circulation cells which are confined between the three interfaces. These results confirm the hypothesis that has been previously suggested based solely on a steady-state numerical modeling defined by a conceptual understanding. Parametric analysis shows that the creation of three circulation cells and three interfaces is limited to certain conditions and defines the ranges for the creation of this unique system.

Development and validation of quasi-steady-state heat pump water heater model having stratified water tank and wrapped-tank condenser

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

Shen, Bo; Nawaz, Kashif; Baxter, Van D.

Heat pump water heater systems (HPWH) introduce new challenges for design and modeling tools, because they require vapor compression system balanced with a water storage tank. In addition, a wrapped-tank condenser coil has strong coupling with a stratified water tank, which leads HPWH simulation to a transient process. To tackle these challenges and deliver an effective, hardware-based HPWH equipment design tool, a quasi-steady-state HPWH model was developed based on the DOE/ORNL Heat Pump Design Model (HPDM). Two new component models were added via this study. One is a one-dimensional stratified water tank model, an improvement to the open-source EnergyPlus watermore » tank model, by introducing a calibration factor to account for bulk mixing effect due to water draws, circulations, etc. The other is a wrapped-tank condenser coil model, using a segment-to-segment modeling approach. In conclusion, the HPWH system model was validated against available experimental data. After that, the model was used for parametric simulations to determine the effects of various design factors.« less

Development and validation of quasi-steady-state heat pump water heater model having stratified water tank and wrapped-tank condenser

DOE PAGES

Shen, Bo; Nawaz, Kashif; Baxter, Van D.; ...

2017-10-31

Heat pump water heater systems (HPWH) introduce new challenges for design and modeling tools, because they require vapor compression system balanced with a water storage tank. In addition, a wrapped-tank condenser coil has strong coupling with a stratified water tank, which leads HPWH simulation to a transient process. To tackle these challenges and deliver an effective, hardware-based HPWH equipment design tool, a quasi-steady-state HPWH model was developed based on the DOE/ORNL Heat Pump Design Model (HPDM). Two new component models were added via this study. One is a one-dimensional stratified water tank model, an improvement to the open-source EnergyPlus watermore » tank model, by introducing a calibration factor to account for bulk mixing effect due to water draws, circulations, etc. The other is a wrapped-tank condenser coil model, using a segment-to-segment modeling approach. In conclusion, the HPWH system model was validated against available experimental data. After that, the model was used for parametric simulations to determine the effects of various design factors.« less

Generalized large-scale semigeostrophic approximations for the f-plane primitive equations

NASA Astrophysics Data System (ADS)

Oliver, Marcel; Vasylkevych, Sergiy

2016-05-01

We derive a family of balance models for rotating stratified flow in the primitive equation (PE) setting. By construction, the models possess conservation laws for energy and potential vorticity and are formally of the same order of accuracy as Hoskins’ semigeostrophic equations. Our construction is based on choosing a new coordinate frame for the PE variational principle in such a way that the consistently truncated Lagrangian degenerates. We show that the balance relations so obtained are elliptic when the fluid is stably stratified and certain smallness assumptions are satisfied. Moreover, the potential temperature can be recovered from the potential vorticity via inversion of a non-standard Monge-Ampère problem which is subject to the same ellipticity condition. While the present work is entirely formal, we conjecture, based on a careful rewriting of the equations of motion and a straightforward derivative count, that the Cauchy problem for the balance models is well posed subject to conditions on the initial data. Our family of models includes, in particular, the stratified analog of the L 1 balance model of Salmon.

Testing of RANS Turbulence Models for Stratified Flows Based on DNS Data

NASA Technical Reports Server (NTRS)

Venayagamoorthy, S. K.; Koseff, J. R.; Ferziger, J. H.; Shih, L. H.

2003-01-01

In most geophysical flows, turbulence occurs at the smallest scales and one of the two most important additional physical phenomena to account for is strati cation (the other being rotation). In this paper, the main objective is to investigate proposed changes to RANS turbulence models which include the effects of stratifi- cation more explicitly. These proposed changes were developed using a DNS database on strati ed and sheared homogenous turbulence developed by Shih et al. (2000) and are described more fully in Ferziger et al. (2003). The data generated by Shih, et al. (2000) (hereinafter referred to as SKFR) are used to study the parameters in the k- model as a function of the turbulent Froude number, Frk. A modified version of the standard k- model based on the local turbulent Froude number is proposed. The proposed model is applied to a stratified open channel flow, a test case that differs significantly from the flows from which the modified parameters were derived. The turbulence modeling and results are discussed in the next two sections followed by suggestions for future work.

Analysis of rotary engine combustion processes based on unsteady, three-dimensional computations

NASA Technical Reports Server (NTRS)

Raju, M. S.; Willis, E. A.

1990-01-01

A new computer code was developed for predicting the turbulent and chemically reacting flows with sprays occurring inside of a stratified charge rotary engine. The solution procedure is based on an Eulerian Lagrangian approach where the unsteady, three-dimensional Navier-Stokes equations for a perfect gas mixture with variable properties are solved in generalized, Eulerian coordinates on a moving grid by making use of an implicit finite volume, Steger-Warming flux vector splitting scheme, and the liquid phase equations are solved in Lagrangian coordinates. Both the details of the numerical algorithm and the finite difference predictions of the combustor flow field during the opening of exhaust and/or intake, and also during fuel vaporization and combustion, are presented.

Analysis of rotary engine combustion processes based on unsteady, three-dimensional computations

NASA Technical Reports Server (NTRS)

Raju, M. S.; Willis, E. A.

1989-01-01

A new computer code was developed for predicting the turbulent, and chemically reacting flows with sprays occurring inside of a stratified charge rotary engine. The solution procedure is based on an Eulerian Lagrangian approach where the unsteady, 3-D Navier-Stokes equations for a perfect gas mixture with variable properties are solved in generalized, Eulerian coordinates on a moving grid by making use of an implicit finite volume, Steger-Warming flux vector splitting scheme, and the liquid phase equations are solved in Lagrangian coordinates. Both the details of the numerical algorithm and the finite difference predictions of the combustor flow field during the opening of exhaust and/or intake, and also during fuel vaporization and combustion, are presented.

Analysing stratified medicine business models and value systems: innovation-regulation interactions.

PubMed

Mittra, James; Tait, Joyce

2012-09-15

Stratified medicine offers both opportunities and challenges to the conventional business models that drive pharmaceutical R&D. Given the increasingly unsustainable blockbuster model of drug development, due in part to maturing product pipelines, alongside increasing demands from regulators, healthcare providers and patients for higher standards of safety, efficacy and cost-effectiveness of new therapies, stratified medicine promises a range of benefits to pharmaceutical and diagnostic firms as well as healthcare providers and patients. However, the transition from 'blockbusters' to what might now be termed 'niche-busters' will require the adoption of new, innovative business models, the identification of different and perhaps novel types of value along the R&D pathway, and a smarter approach to regulation to facilitate innovation in this area. In this paper we apply the Innogen Centre's interdisciplinary ALSIS methodology, which we have developed for the analysis of life science innovation systems in contexts where the value creation process is lengthy, expensive and highly uncertain, to this emerging field of stratified medicine. In doing so, we consider the complex collaboration, timing, coordination and regulatory interactions that shape business models, value chains and value systems relevant to stratified medicine. More specifically, we explore in some depth two convergence models for co-development of a therapy and diagnostic before market authorisation, highlighting the regulatory requirements and policy initiatives within the broader value system environment that have a key role in determining the probable success and sustainability of these models. Copyright © 2012 Elsevier B.V. All rights reserved.

Support of personalized medicine through risk-stratified treatment recommendations - an environmental scan of clinical practice guidelines

PubMed Central

2013-01-01

Background Risk-stratified treatment recommendations facilitate treatment decision-making that balances patient-specific risks and preferences. It is unclear if and how such recommendations are developed in clinical practice guidelines (CPGs). Our aim was to assess if and how CPGs develop risk-stratified treatment recommendations for the prevention or treatment of common chronic diseases. Methods We searched the United States National Guideline Clearinghouse for US, Canadian and National Institute for Health and Clinical Excellence (United Kingdom) CPGs for heart disease, stroke, cancer, chronic obstructive pulmonary disease and diabetes that make risk-stratified treatment recommendations. We included only those CPGs that made risk-stratified treatment recommendations based on risk assessment tools. Two reviewers independently identified CPGs and extracted information on recommended risk assessment tools; type of evidence about treatment benefits and harms; methods for linking risk estimates to treatment evidence and for developing treatment thresholds; and consideration of patient preferences. Results We identified 20 CPGs that made risk-stratified treatment recommendations out of 133 CPGs that made any type of treatment recommendations for the chronic diseases considered in this study. Of the included 20 CPGs, 16 (80%) used evidence about treatment benefits from randomized controlled trials, meta-analyses or other guidelines, and the source of evidence was unclear in the remaining four (20%) CPGs. Nine CPGs (45%) used evidence on harms from randomized controlled trials or observational studies, while 11 CPGs (55%) did not clearly refer to harms. Nine CPGs (45%) explained how risk prediction and evidence about treatments effects were linked (for example, applying estimates of relative risk reductions to absolute risks), but only one CPG (5%) assessed benefit and harm quantitatively and three CPGs (15%) explicitly reported consideration of patient preferences. Conclusions Only a small proportion of CPGs for chronic diseases make risk-stratified treatment recommendations with a focus on heart disease and stroke prevention, diabetes and breast cancer. For most CPGs it is unclear how risk-stratified treatment recommendations were developed. As a consequence, it is uncertain if CPGs support patients and physicians in finding an acceptable benefit- harm balance that reflects both profile-specific outcome risks and preferences. PMID:23302096

Effectiveness of a two-step population-based osteoporosis screening program using FRAX: the randomized Risk-stratified Osteoporosis Strategy Evaluation (ROSE) study.

PubMed

Rubin, K H; Rothmann, M J; Holmberg, T; Høiberg, M; Möller, S; Barkmann, R; Glüer, C C; Hermann, A P; Bech, M; Gram, J; Brixen, K

2018-03-01

The Risk-stratified Osteoporosis Strategy Evaluation (ROSE) study investigated the effectiveness of a two-step screening program for osteoporosis in women. We found no overall reduction in fractures from systematic screening compared to the current case-finding strategy. The group of moderate- to high-risk women, who accepted the invitation to DXA, seemed to benefit from the program. The purpose of the ROSE study was to investigate the effectiveness of a two-step population-based osteoporosis screening program using the Fracture Risk Assessment Tool (FRAX) derived from a self-administered questionnaire to select women for DXA scan. After the scanning, standard osteoporosis management according to Danish national guidelines was followed. Participants were randomized to either screening or control group, and randomization was stratified according to age and area of residence. Inclusion took place from February 2010 to November 2011. Participants received a self-administered questionnaire, and women in the screening group with a FRAX score ≥ 15% (major osteoporotic fractures) were invited to a DXA scan. Primary outcome was incident clinical fractures. Intention-to-treat analysis and two per-protocol analyses were performed. A total of 3416 fractures were observed during a median follow-up of 5 years. No significant differences were found in the intention-to-treat analyses with 34,229 women included aged 65-80 years. The per-protocol analyses showed a risk reduction in the group that underwent DXA scanning compared to women in the control group with a FRAX ≥ 15%, in regard to major osteoporotic fractures, hip fractures, and all fractures. The risk reduction was most pronounced for hip fractures (adjusted SHR 0.741, p = 0.007). Compared to an office-based case-finding strategy, the two-step systematic screening strategy had no overall effect on fracture incidence. The two-step strategy seemed, however, to be beneficial in the group of women who were identified by FRAX as moderate- or high-risk patients and complied with DXA.

Oral and inhaled glucocorticoid use and risk of Achilles or biceps tendon rupture: a population-based case-control study.

PubMed

Spoendlin, Julia; Meier, Christian; Jick, Susan S; Meier, Christoph R

2015-01-01

Tendinotoxicity of glucocorticoids (GC) has been shown, but evidence on how this translates into clinical practice remains scarce. To explore the association between oral or inhaled GC use and the risk of Achilles or biceps tendon rupture (ATR/BTR). We identified patients aged 18 to 89 years with incident ATR or BTR (1995-2013) for a matched (1:4) case-control analysis using the UK-based Clinical Practice Research Datalink. We stratified oral GC use by indication, timing and duration of use, continuous versus intermittent use, cumulative dose, and average daily dose. We stratified inhaled GC use by timing and number of prescriptions. Among 8,202 cases, we observed increased odds ratios (ORs) around 3.0 for continuous oral GC use, which declined shortly after therapy cessation (similarly across indications). Odds ratios increased with average daily dose (≥ 10 mg/day, OR 4.05, 95% CI 2.32-7.08) and were elevated after one cycle of high-dose oral GC (≥ 20 mg/day). There was no effect of inhaled GC at any level of exposure. Our results provide evidence that oral GC therapy increases the risk of tendon rupture in a dose-response relationship. A single short-term high-dose GC treatment course may be sufficient transiently to increase the risk of tendon rupture.

Persistence of Antipsychotic Treatment in Elderly Dementia Patients: A Retrospective, Population-Based Cohort Study.

PubMed

Mast, Gavin; Fernandes, Kimberly; Tadrous, Mina; Martins, Diana; Herrmann, Nathan; Gomes, Tara

2016-06-01

Antipsychotics are commonly used to manage behavioral and psychological symptoms of dementia. Concerns over their safety and efficacy in this role have resulted in antipsychotics typically being recommended for short-term usage only when used among dementia patients. However, there is little work examining the duration of antipsychotic treatment in the elderly dementia patient population. To determine the persistence of use of antipsychotics in elderly dementia patients and the role of dose on therapy duration. A retrospective, population-based cohort study using administrative data, including dispensing records from a provincial public drug program, from Ontario, Canada between 2009 and 2012. Elderly dementia patients newly initiated onto antipsychotics were followed until drug discontinuation, death, 2-year follow-up, or end of study. Competing risk analysis was performed to determine time to discontinuation, stratified by categories of initial dose. After 2 years 49.1 % of the cohort ( N  = 22,927 of 46,695) had discontinued treatment. When stratified by dose, the high-dose group (51.1 % discontinued) discontinued more frequently than the medium- (48.7 % discontinued) and low- (47.5 % discontinued) dose groups ( p  < 0.0001). Approximately half of elderly dementia patients treated with antipsychotics discontinue within 2 years, with those on higher doses more likely to discontinue. However, the number of patients remaining on therapy represents a serious public health concern.

Utilization of medical services in the public health system in the Southern Brazil.

PubMed

Bastos, Gisele Alsina Nader; Duca, Giovâni Firpo Del; Hallal, Pedro Curi; Santos, Iná S

2011-06-01

To estimate the prevalence and analyze factors associated with the utilization of medical services in the public health system. Cross-sectional population-based study with 2,706 individuals aged 20-69 years carried out in Pelotas, Southern Brazil, in 2008. A systematic sampling with probability proportional to the number of households in each sector was adopted. The outcome was defined by the combination of the questions related to medical consultation in the previous three months and place. The exposure variables were: sex, age, marital status, level of schooling, family income, self-reported hospital admission in the previous year, having a regular physician, self-perception of health, and the main reason for the last consultation. Descriptive analysis was stratified by sex and the analytical statistics included the use of the Wald test for tendency and heterogeneity in the crude analysis and Poisson regression with robust variance in the adjusted analysis, taking into consideration cluster sampling. The prevalence of utilization of medical services in the three previous months was 60.6%, almost half of these (42.0%, 95%CI: 36.6;47.5) in public services. The most utilized public services were the primary care units (49.5%). In the adjusted analysis stratified by sex, men with advanced age and young women had higher probability of using the medical services in the public system. In both sexes, low level of schooling, low per capita family income, not having a regular physician and hospital admission in the previous year were associated with the outcome. Despite the expressive reduction in the utilization of medical health services in the public system in the last 15 years, the public services are now reaching a previously unassisted portion of the population (individuals with low income and schooling).

Stratification of a cityscape using census and land use variables for inventory of building materials

USGS Publications Warehouse

Rosenfield, G.H.; Fitzpatrick-Lins, K.; Johnson, T.L.

1987-01-01

A cityscape (or any landscape) can be stratified into environmental units using multiple variables of information. For the purposes of sampling building materials, census and land use variables were used to identify similar strata. In the Metropolitan Statistical Area of a cityscape, the census tract is the smallest unit for which census data are summarized and digitized boundaries are available. For purposes of this analysis, census data on total population, total number of housing units, and number of singleunit dwellings were aggregated into variables of persons per square kilometer and proportion of housing units in single-unit dwellings. The level 2 categories of the U.S. Geological Survey's land use and land cover data base were aggregated into variables of proportion of residential land with buildings, proportion of nonresidential land with buildings, and proportion of open land. The cityscape was stratified, from these variables, into environmental strata of Urban Central Business District, Urban Livelihood Industrial Commercial, Urban Multi-Family Residential, Urban Single Family Residential, Non-Urban Suburbanizing, and Non-Urban Rural. The New England region was chosen as a region with commonality of building materials, and a procedure developed for trial classification of census tracts into one of the strata. Final stratification was performed by discriminant analysis using the trial classification and prior probabilities as weights. The procedure was applied to several cities, and the results analyzed by correlation analysis from a field sample of building materials. The methodology developed for stratification of a cityscape using multiple variables has application to many other types of environmental studies, including forest inventory, hydrologic unit management, waste disposal, transportation studies, and other urban studies. Multivariate analysis techniques have recently been used for urban stratification in England. ?? 1987 Annals of Regional Science.

Deposition and deformation of stratified rocks in the northern Nia Mensa region of Valles Marineris, Mars

NASA Astrophysics Data System (ADS)

Okubo, C. H.

2016-12-01

Large-scale structural and geologic mapping based on HiRISE (High Resolution Imaging Science Experiment) digital elevation models reveals new details of the depositional environment for the stratified rocks in the northern Nia Mensa region of eastern Candor Chasma, Valles Marineris, Mars. The map area encompasses the contact between massive sedimentary rocks that comprise most of Nia Mensa and the stratified sedimentary and mass-wasting deposits exposed between Nia Mensa and the north wall of eastern Candor Chasma. The area contains a stratified fan-like deposit on the lower slopes of Nia Mensa. The strata within this deposit dip outward at < 10°, away from its morphologic apex, consistent with an origin as a depositional fan (rather than being carved into a fan shape by erosion). Whether this fan has a subaerial or submarine origin has not yet been determined. Additionally, the fan and surrounding stratified rocks exhibit evidence of soft-sediment deformation in the form of clastic dikes and contorted bedding, indicating that these deposits were water-saturated at the time of deformation. Finally, the northern section of the map area encompasses part of a fractured rise, and deposits interpreted as mud flows mantle the top of this rise. Inferred flow directions suggest that the mud erupted out of these fractures. These findings place constraints on the depositional environment of the local stratified bedrock. The presence of the fan deposit indicates that lateral transport was a component in the depositional history of these sediments. Therefore the sediments did not form entirely as a mantling deposit, such as air fall ash or sediments settled out of a water column. The soft-sediment deformation and subsurface mobilized sediments indicate that groundwater was present in the area after emplacement of the stratified deposits, but before its lithification. These findings point to a wet-playa to lacustrine depositional environment.

Dose-Dependent Associations between Wine Drinking and Breast Cancer Risk - Meta-Analysis Findings.

PubMed

Chen, Jia-Yan; Zhu, Hong-Cheng; Guo, Qing; Shu, Zheng; Bao, Xu-Hui; Sun, Feng; Qin, Qin; Yang, Xi; Zhang, Chi; Cheng, Hong-Yan; Sun, Xin-Chen

2016-01-01

To investigate any potential association between wine and breast cancer risk. We quantitatively assessed associations by conducting a meta-analysis based on evidence from observational studies. In May 2014, we performed electronic searches in PubMed, EmBase and the Cochrane Library to identify studies examining the effect of wine drinking on breast cancer incidence. The relative risk (RR) or odds ratio (OR) were used to measure any such association. The analysis was further stratified by confounding factors that could influence the results. A total of twenty-six studies (eight case-control and eighteen cohort studies) involving 21,149 cases were included in our meta-analysis. Our study demonstrated that wine drinking was associated with breast cancer risk. A 36% increase in breast cancer risk was observed across overall studies based on the highest versus lowest model, with a combined RR of 1.0059 (95%CI 0.97-1.05) in dose-response analysis. However, 5 g/d ethanol from wine seemed to have protective value from our non-linear model. Our findings indicate that wine drinking is associated with breast cancer risk in a dose-dependent manner. High consumption of wine contributes to breast cancer risk with protection exerted by low doses. Further investigations are needed for clarification.

Patent Foramen Ovale, Ischemic Stroke and Migraine: Systematic Review and Stratified Meta-Analysis of Association Studies

PubMed Central

Davis, Daniel; Gregson, John; Willeit, Peter; Stephan, Blossom; Al-Shahi Salman, Rustam; Brayne, Carol

2012-01-01

Background Observational data have reported associations between patent foramen ovale (PFO), cryptogenic stroke and migraine. However, randomized trials of PFO closure do not demonstrate a clear benefit either because the underlying association is weaker than previously suggested or because the trials were underpowered. In order to resolve the apparent discrepancy between observational data and randomized trials, we investigated associations between (1) migraine and ischemic stroke, (2) PFO and ischemic stroke, and (3) PFO and migraine. Methods Eligibility criteria were consistent; including all studies with specifically defined exposures and outcomes unrestricted by language. We focused on studies at lowest risk of bias by stratifying analyses based on methodological design and quantified associations using fixed-effects meta-analysis models. Results We included 37 studies of 7,686 identified. Compared to reports in the literature as a whole, studies with population-based comparators showed weaker associations between migraine with aura and cryptogenic ischemic stroke in younger women (OR 1.4; 95% CI 0.9–2.0; 1 study), PFO and ischemic stroke (HR 1.6; 95 CI 1.0–2.5; 2 studies; OR 1.3; 95% CI 0.9–1.9; 3 studies), or PFO and migraine (OR 1.0; 95% CI 0.6–1.6; 1 study). It was not possible to look for interactions or effect modifiers. These results are limited by sources of bias within individual studies. Conclusions The overall pairwise associations between PFO, cryptogenic ischemic stroke and migraine do not strongly suggest a causal role for PFO. Ongoing randomized trials of PFO closure may need larger numbers of participants to detect an overall beneficial effect. PMID:23075508

Patent foramen ovale, ischemic stroke and migraine: systematic review and stratified meta-analysis of association studies.

PubMed

Davis, Daniel; Gregson, John; Willeit, Peter; Stephan, Blossom; Al-Shahi Salman, Rustam; Brayne, Carol

2013-01-01

Observational data have reported associations between patent foramen ovale (PFO), cryptogenic stroke and migraine. However, randomized trials of PFO closure do not demonstrate a clear benefit either because the underlying association is weaker than previously suggested or because the trials were underpowered. In order to resolve the apparent discrepancy between observational data and randomized trials, we investigated associations between (1) migraine and ischemic stroke, (2) PFO and ischemic stroke, and (3) PFO and migraine. Eligibility criteria were consistent; including all studies with specifically defined exposures and outcomes unrestricted by language. We focused on studies at lowest risk of bias by stratifying analyses based on methodological design and quantified associations using fixed-effects meta-analysis models. We included 37 studies of 7,686 identified. Compared to reports in the literature as a whole, studies with population-based comparators showed weaker associations between migraine with aura and cryptogenic ischemic stroke in younger women (OR 1.4; 95% CI 0.9-2.0; 1 study), PFO and ischemic stroke (HR 1.6; 95 CI 1.0-2.5; 2 studies; OR 1.3; 95% CI 0.9-1.9; 3 studies), or PFO and migraine (OR 1.0; 95% CI 0.6-1.6; 1 study). It was not possible to look for interactions or effect modifiers. These results are limited by sources of bias within individual studies. The overall pairwise associations between PFO, cryptogenic ischemic stroke and migraine do not strongly suggest a causal role for PFO. Ongoing randomized trials of PFO closure may need larger numbers of participants to detect an overall beneficial effect. Copyright © 2012 S. Karger AG, Basel.

Multiparticle imaging technique for two-phase fluid flows using pulsed laser speckle velocimetry. Final report, September 1988--November 1992

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

Hassan, T.A.

1992-12-01

The practical use of Pulsed Laser Velocimetry (PLV) requires the use of fast, reliable computer-based methods for tracking numerous particles suspended in a fluid flow. Two methods for performing tracking are presented. One method tracks a particle through multiple sequential images (minimum of four required) by prediction and verification of particle displacement and direction. The other method, requiring only two sequential images uses a dynamic, binary, spatial, cross-correlation technique. The algorithms are tested on computer-generated synthetic data and experimental data which was obtained with traditional PLV methods. This allowed error analysis and testing of the algorithms on real engineering flows.more » A novel method is proposed which eliminates tedious, undersirable, manual, operator assistance in removing erroneous vectors. This method uses an iterative process involving an interpolated field produced from the most reliable vectors. Methods are developed to allow fast analysis and presentation of sets of PLV image data. Experimental investigation of a two-phase, horizontal, stratified, flow regime was performed to determine the interface drag force, and correspondingly, the drag coefficient. A horizontal, stratified flow test facility using water and air was constructed to allow interface shear measurements with PLV techniques. The experimentally obtained local drag measurements were compared with theoretical results given by conventional interfacial drag theory. Close agreement was shown when local conditions near the interface were similar to space-averaged conditions. However, theory based on macroscopic, space-averaged flow behavior was shown to give incorrect results if the local gas velocity near the interface as unstable, transient, and dissimilar from the average gas velocity through the test facility.« less

Multiparticle imaging technique for two-phase fluid flows using pulsed laser speckle velocimetry

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

Hassan, T.A.

1992-12-01

The practical use of Pulsed Laser Velocimetry (PLV) requires the use of fast, reliable computer-based methods for tracking numerous particles suspended in a fluid flow. Two methods for performing tracking are presented. One method tracks a particle through multiple sequential images (minimum of four required) by prediction and verification of particle displacement and direction. The other method, requiring only two sequential images uses a dynamic, binary, spatial, cross-correlation technique. The algorithms are tested on computer-generated synthetic data and experimental data which was obtained with traditional PLV methods. This allowed error analysis and testing of the algorithms on real engineering flows.more » A novel method is proposed which eliminates tedious, undersirable, manual, operator assistance in removing erroneous vectors. This method uses an iterative process involving an interpolated field produced from the most reliable vectors. Methods are developed to allow fast analysis and presentation of sets of PLV image data. Experimental investigation of a two-phase, horizontal, stratified, flow regime was performed to determine the interface drag force, and correspondingly, the drag coefficient. A horizontal, stratified flow test facility using water and air was constructed to allow interface shear measurements with PLV techniques. The experimentally obtained local drag measurements were compared with theoretical results given by conventional interfacial drag theory. Close agreement was shown when local conditions near the interface were similar to space-averaged conditions. However, theory based on macroscopic, space-averaged flow behavior was shown to give incorrect results if the local gas velocity near the interface as unstable, transient, and dissimilar from the average gas velocity through the test facility.« less

Precarious employment and the risk of serious psychological distress: a population-based cohort study in Japan.

PubMed

Kachi, Yuko; Otsuka, Toshiaki; Kawada, Tomoyuki

2014-09-01

This study examines whether precarious employment increases the risk of serious psychological distress (SPD) in a nationally representative cohort of Japanese middle-aged people. From 2005-2009, we followed 8486 male and 6736 female participants (aged 50-59 years) in the Longitudinal Survey of Middle-aged and Elderly Persons. All individuals were employed and free of SPD, cardiovascular disease, and cancer at baseline. The participants were classified into two groups based on their baseline employment contract: precarious and full-time permanent work. SPD was assessed at each year during the study, using the K6 scale, a self-rated 6-item scale that screens for mood or anxiety disorders. We used discrete-time survival analysis, with a complementary log-log link, to examine the effect of precarious employment on SPD incidence. During a maximum follow-up period of four years, 374 men and 364 women developed SPD. Male precarious employees were more likely to develop SPD than male full-time permanent employees (hazard ratio 1.79, 95% confidence interval 1.28-2.51) in the full model, after adjusting for sociodemographic and occupational factors, cardiovascular disease risk, and K6 scores at baseline. By contrast, no significant association was observed among female employees. However, an analysis stratified by marital status revealed an association similar to that found among men but only among unmarried women. The findings suggest that precarious employment is associated with double the risk of SPD incidence among middle-aged Japanese men and - when stratified by marital status - among unmarried women. This highlights a major gender difference in the association between precarious employment and risk of SPD.

A Tissue Systems Pathology Assay for High-Risk Barrett's Esophagus.

PubMed

Critchley-Thorne, Rebecca J; Duits, Lucas C; Prichard, Jeffrey W; Davison, Jon M; Jobe, Blair A; Campbell, Bruce B; Zhang, Yi; Repa, Kathleen A; Reese, Lia M; Li, Jinhong; Diehl, David L; Jhala, Nirag C; Ginsberg, Gregory; DeMarshall, Maureen; Foxwell, Tyler; Zaidi, Ali H; Lansing Taylor, D; Rustgi, Anil K; Bergman, Jacques J G H M; Falk, Gary W

2016-06-01

Better methods are needed to predict risk of progression for Barrett's esophagus. We aimed to determine whether a tissue systems pathology approach could predict progression in patients with nondysplastic Barrett's esophagus, indefinite for dysplasia, or low-grade dysplasia. We performed a nested case-control study to develop and validate a test that predicts progression of Barrett's esophagus to high-grade dysplasia (HGD) or esophageal adenocarcinoma (EAC), based upon quantification of epithelial and stromal variables in baseline biopsies. Data were collected from Barrett's esophagus patients at four institutions. Patients who progressed to HGD or EAC in ≥1 year (n = 79) were matched with patients who did not progress (n = 287). Biopsies were assigned randomly to training or validation sets. Immunofluorescence analyses were performed for 14 biomarkers and quantitative biomarker and morphometric features were analyzed. Prognostic features were selected in the training set and combined into classifiers. The top-performing classifier was assessed in the validation set. A 3-tier, 15-feature classifier was selected in the training set and tested in the validation set. The classifier stratified patients into low-, intermediate-, and high-risk classes [HR, 9.42; 95% confidence interval, 4.6-19.24 (high-risk vs. low-risk); P < 0.0001]. It also provided independent prognostic information that outperformed predictions based on pathology analysis, segment length, age, sex, or p53 overexpression. We developed a tissue systems pathology test that better predicts risk of progression in Barrett's esophagus than clinicopathologic variables. The test has the potential to improve upon histologic analysis as an objective method to risk stratify Barrett's esophagus patients. Cancer Epidemiol Biomarkers Prev; 25(6); 958-68. ©2016 AACR. ©2016 American Association for Cancer Research.

The relationship between urban environment and the inflammatory bowel diseases: a systematic review and meta-analysis.

PubMed

Soon, Ing Shian; Molodecky, Natalie A; Rabi, Doreen M; Ghali, William A; Barkema, Herman W; Kaplan, Gilaad G

2012-05-24

The objective of this study was to conduct a systematic review with meta-analysis of studies assessing the association between living in an urban environment and the development of the Crohn's disease (CD) or ulcerative colitis (UC). A systematic literature search of MEDLINE (1950-Oct. 2009) and EMBASE (1980-Oct. 2009) was conducted to identify studies investigating the relationship between urban environment and IBD. Cohort and case-control studies were analyzed using incidence rate ratio (IRR) or odds ratio (OR) with 95 % confidence intervals (CIs), respectively. Stratified and sensitivity analyses were performed to explore heterogeneity between studies and assess effects of study quality. The search strategy retrieved 6940 unique citations and 40 studies were selected for inclusion. Of these, 25 investigated the relationship between urban environment and UC and 30 investigated this relationship with CD. Included in our analysis were 7 case-control UC studies, 9 case-control CD studies, 18 cohort UC studies and 21 cohort CD studies. Based on a random effects model, the pooled IRRs for urban compared to rural environment for UC and CD studies were 1.17 (1.03, 1.32) and 1.42 (1.26, 1.60), respectively. These associations persisted across multiple stratified and sensitivity analyses exploring clinical and study quality factors. Heterogeneity was observed in the cohort studies for both UC and CD, whereas statistically significant heterogeneity was not observed for the case-control studies. A positive association between urban environment and both CD and UC was found. Heterogeneity may be explained by differences in study design and quality factors.

Performance and combustion characteristics of direct-injection stratified-charge rotary engines

NASA Technical Reports Server (NTRS)

Nguyen, Hung Lee

1987-01-01

Computer simulations of the direct-injection stratified-charge (DISC) Wankel engine have been used to calculate heat release rates and performance and efficiency characteristics of the 1007R engine. Engine pressure data have been used in a heat release analysis to study the effects of heat transfer, leakage, and crevice flows. Predicted engine performance data are compared with experimental test data over a range of engine speeds and loads. An examination of methods to improve the performance of the Wankel engine with faster combustion, reduced leakage, higher compression ratio, and turbocharging is presented.

Analysis of regional-scale vegetation dynamics of Mexico using stratified AVHRR NDVI data. [Normalized Difference Vegetaion Index

NASA Technical Reports Server (NTRS)

Turcotte, Kevin M.; Kramber, William J.; Venugopal, Gopalan; Lulla, Kamlesh

1989-01-01

Previous studies have shown that a good relationship exists between AVHRR Normalized Difference Vegetation Index (NDVI) measurements, and both regional-scale patterns of vegetation seasonality and productivity. Most of these studies used known samples of vegetation types. An alternative approach, and the objective was to examine the above relationships by analyzing one year of AVHRR NDVI data that was stratified using a small-scale vegetation map of Mexico. The results show that there is a good relationship between AVHRR NDVI measurements and regional-scale vegetation dynamics of Mexico.

A Citation Analysis of Who's Who in Introductory Textbooks

ERIC Educational Resources Information Center

Griggs, Richard A.; Proctor, Derrick L.

2002-01-01

Given the many changes in the introductory psychology textbook market in the past 2 decades and the lack of a recent citation study of introductory texts, we conducted a citation analysis of a stratified random sample of current texts. To provide a more comprehensive picture of current citation emphases, we extended our analysis to the top 60…

[Developing Perceived Competence Scale (PCS) for Adolescents].

PubMed

Özer, Arif; Gençtanirim Kurt, Dilek; Kizildağ, Seval; Demırtaş Zorbaz, Selen; Arici Şahın, Fatma; Acar, Tülin; Ergene, Tuncay

2016-01-01

In this study, Perceived Competence Scale was developed to measure high school students' perceived competence. Scale development process was verified on three different samples. Participants of the research are some high school students in 2011-2012 academic terms from Ankara. Participants' numbers are incorporated in exploratory factor analysis, confirmatory factor analysis and test-retest reliability respectively, as follows: 372, 668 and 75. Internal consistency coefficients (Cronbach's and stratified α) are calculated separately for each group. For data analysis Factor 8.02 and LISREL 8.70 package programs were used. According to results of the analyses, internal consistency coefficients (α) are .90 - .93 for academic competence, .82 - .86 for social competence in the samples that exploratory and confirmatory factor analysis performed. For the whole scale internal consistency coefficient (stratified α) is calculated as .91. As a result of test-retest reliability, adjusted correlation coefficients (r) are .94 for social competence and .90 for academic competence. In addition, to fit indexes and regression weights obtained from factor analysis, findings related convergent and discriminant validity, indicating that competence can be addressed in two dimensions which are academic (16 items) and social (14 items).

Realist theory construction for a mixed method multilevel study of neighbourhood context and postnatal depression.

PubMed

Eastwood, John G; Kemp, Lynn A; Jalaludin, Bin B

2016-01-01

We have recently described a protocol for a study that aims to build a theory of neighbourhood context and postnatal depression. That protocol proposed a critical realist Explanatory Theory Building Method comprising of an: (1) emergent phase, (2) construction phase, and (3) confirmatory phase. A concurrent triangulated mixed method multilevel cross-sectional study design was described. The protocol also described in detail the Theory Construction Phase which will be presented here. The Theory Construction Phase will include: (1) defining stratified levels; (2) analytic resolution; (3) abductive reasoning; (4) comparative analysis (triangulation); (5) retroduction; (6) postulate and proposition development; (7) comparison and assessment of theories; and (8) conceptual frameworks and model development. The stratified levels of analysis in this study were predominantly social and psychological. The abductive analysis used the theoretical frames of: Stress Process; Social Isolation; Social Exclusion; Social Services; Social Capital, Acculturation Theory and Global-economic level mechanisms. Realist propositions are presented for each analysis of triangulated data. Inference to best explanation is used to assess and compare theories. A conceptual framework of maternal depression, stress and context is presented that includes examples of mechanisms at psychological, social, cultural and global-economic levels. Stress was identified as a necessary mechanism that has the tendency to cause several outcomes including depression, anxiety, and health harming behaviours. The conceptual framework subsequently included conditional mechanisms identified through the retroduction including the stressors of isolation and expectations and buffers of social support and trust. The meta-theory of critical realism is used here to generate and construct social epidemiological theory using stratified ontology and both abductive and retroductive analysis. The findings will be applied to the development of a middle range theory and subsequent programme theory for local perinatal child and family interventions.

Significance of sarcopenia as a prognostic factor for metastatic urothelial carcinoma patients treated with systemic chemotherapy.

PubMed

Abe, Hideyuki; Takei, Kohei; Uematsu, Toshitaka; Tokura, Yuumi; Suzuki, Issei; Sakamoto, Kazumasa; Nishihara, Daisaku; Yamaguchi, Yoshiyuki; Mizuno, Tomoya; Nukui, Akinori; Kobayashi, Minoru; Kamai, Takao

2018-04-01

Recently, numerous studies have reported an association between sarcopenia and poor outcomes in various kinds of malignancies. We investigated whether sarcopenia predicts the survival of patients with metastatic urothelial carcinoma who underwent systemic chemotherapy. We reviewed 87 metastatic urothelial carcinoma patients who underwent chemotherapy (gemcitabine plus cisplatin or gemcitabine plus carboplatin for cisplatin-unfit patients) between 2007 and 2015. A computed tomography scan prior to chemotherapy was used for evaluating sarcopenia, and we measured three cross-sectional areas of skeletal muscle at the third lumbar vertebra and calculated the skeletal muscle index (SMI), the paraspinal muscle index (PSMI), and the total psoas area (TPA) of each patient. Predictive values of survival were assessed using Cox regression analysis. The median overall survival (OS) was 16 months (95% CI 13.5-18). Although SMI alone was not a significant predictor of shorter OS (P = 0.117) in univariate analysis, SMI stratified by the value of the body mass index (BMI) was a significant predictor of shorter OS in univariate analysis (P = 0.037) and was also an independent predictor of shorter OS in multivariate analysis (P = 0.026). PSMI and TPA were not significant prognostic factors even when stratified by BMI (P = 0.294 and 0.448), respectively. Neither PSMI nor TPA could substitute SMI as a predictor for poor outcomes in metastatic urothelial carcinoma patients treated with systemic chemotherapy in our study. SMI stratified by BMI is a useful predictor of prognosis in these patients.

The Relationship between Serum Zinc Level and Heart Failure: A Meta-Analysis

PubMed Central

Yu, Xuefang; Huang, Lei; Zhao, Jinyan; Wang, Zhuoqun; Yao, Wei; Wu, Xianming; Huang, Jingjing

2018-01-01

Zinc is essential for the maintenance of normal cellular structure and functions. Zinc dyshomeostasis can lead to many diseases, such as cardiovascular disease. However, there are conflicting reports on the relationship between serum zinc levels and heart failure (HF). The purpose of the present study is to explore the relationship between serum zinc levels and HF by using a meta-analysis approach. PubMed, Web of Science, and OVID databases were searched for reports on the association between serum zinc levels and HF until June 2016. 12 reports with 1453 subjects from 27 case-control studies were chosen for the meta-analysis. Overall, the pooled analysis indicated that patients with HF had lower zinc levels than the control subjects. Further subgroup analysis stratified by different geographic locations also showed that HF patients had lower zinc levels than the control subjects. In addition, subgroup analysis stratified by HF subgroups found that patients with idiopathic dilated cardiomyopathy (IDCM) had lower zinc levels than the control subjects, except for patients with ischemic cardiomyopathy (ICM). In conclusion, the results of the meta-analysis indicate that there is a significant association between low serum zinc levels and HF. PMID:29682528

Development of the GREEN (Garden Resources, Education, and Environment Nexus) Tool: An Evidence-Based Model for School Garden Integration.

PubMed

Burt, Kate Gardner; Koch, Pamela; Contento, Isobel

2017-10-01

Researchers have established the benefits of school gardens on students' academic achievement, dietary outcomes, physical activity, and psychosocial skills, yet limited research has been conducted about how school gardens become institutionalized and sustained. Our aim was to develop a tool that captures how gardens are effectively established, integrated, and sustained in schools. We conducted a sequential, exploratory, mixed-methods study. Participants were identified with the help of Grow To Learn, the organization coordinating the New York City school garden initiative, and recruited via e-mail. A stratified, purposeful sample of 21 New York City elementary and middle schools participated in this study throughout the 2013/2014 school year. The sample was stratified in their garden budgets and purposeful in that each of the schools' gardens were determined to be well integrated and sustained. The processes and strategies used by school gardeners to establish well-integrated school gardens were assessed via data collected from surveys, interviews, observations, and concept mapping. Descriptive statistics as well as multidimensional scaling and hierarchical cluster analysis were used to examine the survey and concept mapping data. Qualitative data analysis consisted of thematic coding, pattern matching, explanation building and cross-case synthesis. Nineteen components within four domains of school garden integration were found through the mixed-methods concept mapping analysis. When the analyses of other data were combined, relationships between domains and components emerged. These data resulted in the development of the GREEN (Garden Resources, Education, and Environment Nexus) Tool. When schools with integrated and sustained gardens were studied, patterns emerged about how gardeners achieve institutionalization through different combinations of critical components. These patterns are best described by the GREEN Tool, the first framework to identify how to operationalize school gardening components and describe an evidence-based strategy of successful school garden integration. Copyright © 2017 Academy of Nutrition and Dietetics. Published by Elsevier Inc. All rights reserved.

Obesity and response to anti-tumor necrosis factor-α agents in patients with select immune-mediated inflammatory diseases: A systematic review and meta-analysis.

PubMed

Singh, Siddharth; Facciorusso, Antonio; Singh, Abha G; Casteele, Niels Vande; Zarrinpar, Amir; Prokop, Larry J; Grunvald, Eduardo L; Curtis, Jeffrey R; Sandborn, William J

2018-01-01

We sought to evaluate the association between obesity and response to anti-tumor necrosis factor-α (TNF) agents, through a systematic review and meta-analysis. Through a systematic search through January 24, 2017, we identified randomized controlled trials (RCTs) or observational studies in adults with select immune-mediated inflammatory diseases-inflammatory bowel diseases (IBD), rheumatoid arthritis (RA), spondyloarthropathies (SpA), psoriasis and psoriatic arthritis (PsA)-treated with anti-TNF agents, and reporting outcomes, stratified by body mass index (BMI) categories or weight. Primary outcome was failure to achieve clinical remission or response or treatment modification. We performed random effects meta-analysis and estimated odds ratios (OR) and 95% confidence interval (CI). Based on 54 cohorts including 19,372 patients (23% obese), patients with obesity had 60% higher odds of failing therapy (OR,1.60; 95% CI,1.39-1.83;I2 = 71%). Dose-response relationship was observed (obese vs. normal BMI: OR,1.87 [1.39-2.52]; overweight vs. normal BMI: OR,1.38 [1.11-1.74],p = 0.11); a 1kg/m2 increase in BMI was associated with 6.5% higher odds of failure (OR,1.065 [1.043-1.087]). These effects were observed across patients with rheumatic diseases, but not observed in patients with IBD. Effect was consistent based on dosing regimen/route, study design, exposure definition, and outcome measures. Less than 10% eligible RCTs reported outcomes stratified by BMI. Obesity is an under-reported predictor of inferior response to anti-TNF agents in patients with select immune-mediated inflammatory diseases. A thorough evaluation of obesity as an effect modifier in clinical trials is warranted, and intentional weight loss may serve as adjunctive treatment in patients with obesity failing anti-TNF therapy.

On the Chronological Structure of the Solutrean in Southern Iberia

PubMed Central

Cascalheira, João; Bicho, Nuno

2015-01-01

The Solutrean techno-complex has gained particular significance over time for representing a clear demographic and techno-typological deviation from the developments occurred during the course of the Upper Paleolithic in Western Europe. Some of Solutrean’s most relevant features are the diversity and techno-typological characteristics of the lithic armatures. These have been recurrently used as pivotal elements in numerous Solutrean-related debates, including the chronological organization of the techno-complex across Iberia and Southwestern France. In Southern Iberia, patterns of presence and/or absence of specific point types in stratified sequences tend to validate the classical ordering of the techno-complex into Lower, Middle and Upper phases, although some evidence, namely radiocarbon determinations, have not always been corroborative. Here we present the first comprehensive analysis of the currently available radiocarbon data for the Solutrean in Southern Iberia. We use a Bayesian statistical approach from 13 stratified sequences to compare the duration, and the start and end moments of each classic Solutrean phase across sites. We conclude that, based on the current data, the traditional organization of the Solutrean cannot be unquestionably confirmed for Southern Iberia, calling into doubt the status of the classically-defined type-fossils as precise temporal markers. PMID:26355459

Blood pressure at age 60-65 versus age 70-75 and vascular dementia: a population based observational study.

PubMed

Peng, Mingkai; Chen, Guanmin; Tang, Karen L; Quan, Hude; Smith, Eric E; Faris, Peter; Hachinski, Vladimir; Campbell, Norm R C

2017-10-27

Vascular dementia (VaD) is the second most common form of dementia. However, there were mixed evidences about the association between blood pressure (BP) and risk of VaD in midlife and late life and limited evidence on the association between pulse pressure and VaD. This is a population-based observational study. 265,897 individuals with at least one BP measurement between the ages of 60 to 65 years and 211,116 individuals with at least one BP measurement between the ages of 70 to 75 years were extracted from The Health Improvement Network in United Kingdom. Blood pressures were categorized into four groups: normal, prehypertension, stage 1 hypertension, and stage 2 hypertension. Cases of VaD were identified from the recorded clinical diagnoses. Multivariable survival analysis was used to adjust other confounders and competing risk of death. All the analysis were stratified based on antihypertensive drug use status. Multiple imputation was used to fill in missing values. After accounting for the competing risk of death and adjustment for potential confounders, there was an association between higher BP levels in the age 60-65 cohort with the risk of developing VaD (hazard ratio [HR] 1.53 (95% confidence interval: 1.04, 2.25) for prehypertension, 1.90 (1.30, 2.78) for stage 1 hypertension, and 2.19 (1.48, 3.26) for stage 2 hypertension) in the untreated group. There was no statistically significant association between BP levels and VaD in the treated group in the age 60-65 cohort and age 70-75 cohort. Analysis on Pulse Pressure (PP) stratified by blood pressure level showed that PP was not independently associated with VaD. High BP between the ages of 60 to 65 years is a significant risk for VaD in late midlife. Greater efforts should be placed on early diagnosis of hypertension and tight control of BP for hypertensive patients for the prevention of VaD.

Half wavelength dipole antennas over stratified media

NASA Technical Reports Server (NTRS)

Latorraca, G. A.

1972-01-01

Theoretical solutions of the fields induced by half-wavelength, horizontal, electric field dipoles (HEDS) are determined based on studies of infinitesimal, horizontal, electric field dipoles over low loss plane-stratified media. To determine these solutions, an approximation to the current distribution of a half-wavelength HED is derived and experimentally verified. Traverse and antenna measurements obtained on the Athabasca Glacier in the summer of 1971 are related to the characteristics of the transmitting antenna design, and the measurement techniques and field equipment used in the glacier trials are described and evaluated.

Proteomic Analysis of Disease Stratified Human Pancreas Tissue Indicates Unique Signature of Type 1 Diabetes.

PubMed

Burch, Tanya C; Morris, Margaret A; Campbell-Thompson, Martha; Pugliese, Alberto; Nadler, Jerry L; Nyalwidhe, Julius O

2015-01-01

Type 1 diabetes (T1D) and type 2 diabetes (T2D) are associated with functional beta cell loss due to ongoing inflammation. Despite shared similarities, T1D is an autoimmune disease with evidence of autoantibody production, as well as a role for exocrine pancreas involvement. Our hypothesis is that differential protein expression occurs in disease stratified pancreas tissues and regulated proteins from endocrine and exocrine tissues are potential markers of disease and potential therapeutic targets. The study objective was to identify novel proteins that distinguish the pancreas from donors with T1D from the pancreas from patients with T2D, or autoantibody positive non-diabetic donors. Detailed quantitative comprehensive proteomic analysis was applied to snap frozen human pancreatic tissue lysates from organ donors without diabetes, with T1D-associated autoantibodies in the absence of diabetes, with T1D, or with T2D. These disease-stratified human pancreas tissues contain exocrine and endocrine tissues (with dysfunctional islets) in the same microenvironment. The expression profiles of several of the proteins were further verified by western blot. We identified protein panels that are significantly and uniquely upregulated in the three disease-stratified pancreas tissues compared to non-disease control tissues. These proteins are involved in inflammation, metabolic regulation, and autoimmunity, all of which are pathways linked to, and likely involved in, T1 and T2 diabetes pathogenesis. Several new proteins were differentially upregulated in prediabetic, T1D, and T2D pancreas. The results identify proteins that could serve as novel prognostic, diagnostic, and therapeutic tools to preserve functional islet mass in Type 1 Diabetes.

Molecular subtyping of bladder cancer using Kohonen self-organizing maps

PubMed Central

Borkowska, Edyta M; Kruk, Andrzej; Jedrzejczyk, Adam; Rozniecki, Marek; Jablonowski, Zbigniew; Traczyk, Magdalena; Constantinou, Maria; Banaszkiewicz, Monika; Pietrusinski, Michal; Sosnowski, Marek; Hamdy, Freddie C; Peter, Stefan; Catto, James WF; Kaluzewski, Bogdan

2014-01-01

Kohonen self-organizing maps (SOMs) are unsupervised Artificial Neural Networks (ANNs) that are good for low-density data visualization. They easily deal with complex and nonlinear relationships between variables. We evaluated molecular events that characterize high- and low-grade BC pathways in the tumors from 104 patients. We compared the ability of statistical clustering with a SOM to stratify tumors according to the risk of progression to more advanced disease. In univariable analysis, tumor stage (log rank P = 0.006) and grade (P < 0.001), HPV DNA (P < 0.004), Chromosome 9 loss (P = 0.04) and the A148T polymorphism (rs 3731249) in CDKN2A (P = 0.02) were associated with progression. Multivariable analysis of these parameters identified that tumor grade (Cox regression, P = 0.001, OR.2.9 (95% CI 1.6–5.2)) and the presence of HPV DNA (P = 0.017, OR 3.8 (95% CI 1.3–11.4)) were the only independent predictors of progression. Unsupervised hierarchical clustering grouped the tumors into discreet branches but did not stratify according to progression free survival (log rank P = 0.39). These genetic variables were presented to SOM input neurons. SOMs are suitable for complex data integration, allow easy visualization of outcomes, and may stratify BC progression more robustly than hierarchical clustering. PMID:25142434

An improved algorithm of image processing technique for film thickness measurement in a horizontal stratified gas-liquid two-phase flow

NASA Astrophysics Data System (ADS)

Kuntoro, Hadiyan Yusuf; Hudaya, Akhmad Zidni; Dinaryanto, Okto; Majid, Akmal Irfan; Deendarlianto

2016-06-01

Due to the importance of the two-phase flow researches for the industrial safety analysis, many researchers developed various methods and techniques to study the two-phase flow phenomena on the industrial cases, such as in the chemical, petroleum and nuclear industries cases. One of the developing methods and techniques is image processing technique. This technique is widely used in the two-phase flow researches due to the non-intrusive capability to process a lot of visualization data which are contain many complexities. Moreover, this technique allows to capture direct-visual information data of the flow which are difficult to be captured by other methods and techniques. The main objective of this paper is to present an improved algorithm of image processing technique from the preceding algorithm for the stratified flow cases. The present algorithm can measure the film thickness (hL) of stratified flow as well as the geometrical properties of the interfacial waves with lower processing time and random-access memory (RAM) usage than the preceding algorithm. Also, the measurement results are aimed to develop a high quality database of stratified flow which is scanty. In the present work, the measurement results had a satisfactory agreement with the previous works.

An improved algorithm of image processing technique for film thickness measurement in a horizontal stratified gas-liquid two-phase flow

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

Kuntoro, Hadiyan Yusuf, E-mail: hadiyan.y.kuntoro@mail.ugm.ac.id; Majid, Akmal Irfan; Deendarlianto, E-mail: deendarlianto@ugm.ac.id

Due to the importance of the two-phase flow researches for the industrial safety analysis, many researchers developed various methods and techniques to study the two-phase flow phenomena on the industrial cases, such as in the chemical, petroleum and nuclear industries cases. One of the developing methods and techniques is image processing technique. This technique is widely used in the two-phase flow researches due to the non-intrusive capability to process a lot of visualization data which are contain many complexities. Moreover, this technique allows to capture direct-visual information data of the flow which are difficult to be captured by other methodsmore » and techniques. The main objective of this paper is to present an improved algorithm of image processing technique from the preceding algorithm for the stratified flow cases. The present algorithm can measure the film thickness (h{sub L}) of stratified flow as well as the geometrical properties of the interfacial waves with lower processing time and random-access memory (RAM) usage than the preceding algorithm. Also, the measurement results are aimed to develop a high quality database of stratified flow which is scanty. In the present work, the measurement results had a satisfactory agreement with the previous works.« less

Numerical study on interaction of local air cooler with stratified hydrogen cloud in a large vessel

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

Liang, Z.; Andreani, M.

2012-07-01

Within the framework of the ERCOSAM project, planning calculations are performed to examine sensitivity parameters that can affect the break-up (erosion) of a helium layer by mitigation devices (i.e., cooler, spray, or Passive Autocatalytic Recombiner - PAR). This paper reports the GOTHIC analysis results for the cooler tests to be performed in the PANDA facility. The cooler elevation and geometry, helium layer thickness, steam distribution in the vessel, and the vessel geometry (inter-connected multi-compartments versus a single volume) on the erosion process as well as the cooling capacity are studied. This analysis is valuable because only a limited number ofmore » conditions will be examined in the planned experiments. The study provides a useful understanding of the interaction of a cooler with a stratified atmosphere. (authors)« less

An affordable and accurate conductivity probe for density measurements in stratified flows

NASA Astrophysics Data System (ADS)

Carminati, Marco; Luzzatto-Fegiz, Paolo

2015-11-01

In stratified flow experiments, conductivity (combined with temperature) is often used to measure density. The probes typically used can provide very fine spatial scales, but can be fragile, expensive to replace, and sensitive to environmental noise. A complementary instrument, comprising a low-cost conductivity probe, would prove valuable in a wide range of applications where resolving extremely small spatial scales is not needed. We propose using micro-USB cables as the actual conductivity sensors. By removing the metallic shield from a micro-B connector, 5 gold-plated microelectrodes are exposed and available for 4-wire measurements. These have a cell constant ~550m-1, an intrinsic thermal noise of at most 30pA/Hz1/2, as well as sub-millisecond time response, making them highly suitable for many stratified flow measurements. In addition, we present the design of a custom electronic board (Arduino-based and Matlab-controlled) for simultaneous acquisition from 4 sensors, with resolution (in conductivity, and resulting density) exceeding the performance of typical existing probes. We illustrate the use of our conductivity-measuring system through stratified flow experiments, and describe plans to release simple instructions to construct our complete system for around 200.

THE WESTERN LAKE SUPERIOR COMPARATIVE WATERSHED FRAMEWORK: A FIELD TEST OF GEOGRAPHICALLY-DEPENDENT VS. THRESHOLD-BASED GEOGRAPHICALLY-INDEPENDENT CLASSIFICATION

EPA Science Inventory

Stratified random selection of watersheds allowed us to compare geographically-independent classification schemes based on watershed storage (wetland + lake area/watershed area) and forest fragmentation with a geographically-based classification scheme within the Northern Lakes a...

Level of literacy and dementia: A secondary post-hoc analysis from North-West India.

PubMed

Raina, Sunil Kumar; Chander, Vishav; Kumar, Dinesh; Raina, Sujeet; Bhardwaj, Ashok

2014-10-01

A relation between literacy and dementia has been studied in past and an association has been documented. This is in spite of some studies pointing to the contrary. The current study was aimed at investigating the influence of level of literacy on dementia in a sample stratified by geography (Migrant, Urban, Rural and Tribal areas of sub-Himalayan state of Himachal Pradesh, India). The study was based on post-hoc analysis of data obtained from a study conducted on elderly population (60 years and above) from selected geographical areas (Migrant, Urban, Rural and Tribal) of Himachal Pradesh state in North-west India. Analysis of variance revealed an effect of education on cognitive scores [F = 2.823, P =0.01], however, post-hoc Tukey's HSD test did not reveal any significant pairwise comparisons. The possibility that education effects dementia needs further evaluation, more so in Indian context.

Analysis of forest structure using thematic mapper simulator data

NASA Technical Reports Server (NTRS)

Peterson, D. L.; Westman, W. E.; Brass, J. A.; Stephenson, N. J.; Ambrosia, V. G.; Spanner, M. A.

1986-01-01

The potential of Thematic Mapper Simulator (TMS) data for sensing forest structure information has been explored by principal components and feature selection techniques. In a survey of forest structural properties conducted for 123 field sites of the Sequoia National Park, the canopy closure could be well estimated (r = 0.62 to 0.69) by a variety of channel bands and band ratios, without reference to the forest type. Estimation of the basal area was less successful (r = 0.51 or less) on the average, but could be improved for certain forest types when data were stratified by floristic composition. To achieve such a stratification, individual sites were ordinated by a detrended correspondence analysis based on the canopy of dominant species. The analysis of forest structure in the Sequoia data suggests that total basal area can be best predicted in stands of lower density, and in younger even-aged managed stands.

Experimental and Numerical Investigation of Internal Gravity Waves Excited by Turbulent Penetrative Convection in Water Around Its Density Maximum

NASA Astrophysics Data System (ADS)

Perrard, Stéphane; Le Bars, Michaël; Le Gal, Patrice

This study is devoted to the experimental and numerical analysis of the excitation of gravity waves by turbulent convection. This situation is representative of many geophysical or astrophysical systems such as the convective bottom layer of the atmosphere that radiates internal waves in the stratosphere, or the interaction between the convective and the radiative zones in stars. In our experiments, we use water as a working fluid as it possesses the remarkable property of having a maximum density at 4 °C. Therefore, when establishing on a water layer a temperature gradient between 0 °C at the bottom and room temperature at the top, a turbulent convective region appears spontaneously under a stably stratified zone. In these conditions, gravity waves are excited by the convective fluid motions penetrating the stratified layer. Although this type of flow, called penetrative convection, has already been described, we present here the first velocity field measurement of wave emission and propagation. We show in particular that an intermediate layer that we call the buffer layer emerges between the convective and the stratified zones. In this buffer layer, the angle of propagation of the waves varies with the altitude since it is slaved to the Brunt-Väisälä frequency which evolves rapidly between the convective and the stratified layer. A minimum angle is reached at the end of the buffer layer. Then we observe that an angle of propagation is selected when the waves travel through the stratified layer. We expect this process of wave selection to take place in natural situations.

The growth and breakdown of a vortex-pair in a stably stratified fluid

NASA Astrophysics Data System (ADS)

Advaith, S.; Tinaikar, Aashay; Manu, K. V.; Basu, Saptarshi

2017-11-01

Vortex interaction with density stratification is ubiquitous in nature and applied to various engineering applications. Present study have characterized the spatial and temporal dynamics of the interaction between a vortex and a density stratified interface. The present work is prompted by our research on single tank Thermal Energy Storage (TES) system used in concentrated solar power (CSP) plants where hot and cold fluids are separated by means of density stratification. Rigorous qualitative (High speed Shadowgraph) and quantitative (high speed PIV) studies enable us to have great understanding about vortex formation, propagation, interaction dynamics with density stratified interface, resulted plume characteristics and so on. We have categorized this interaction phenomena in to three different cases based on its nature as non-penetrative, partial penetrative and extensively penetrative. Along with that we have proposed a regime map consisting non-dimensional parameters like Reynolds, Richardson and Atwood numbers which predicts the occurrence above mentioned cases.

Ultrasonically Assisted Cutting of Bio-tissues in Microtomy

NASA Astrophysics Data System (ADS)

Wang, Dong; Roy, Anish; Silberschmidt, Vadim V.

Modern-day histology of bio-tissues for supporting stratified medicine diagnoses requires high-precision cutting to ensure high quality extremely thin specimens used in analysis. Additionally, the cutting quality is significantly affected by a wide variety of soft and hard tissues in the samples. This paper deals with development of a next generation of microtome employing introduction of controlled ultrasonic vibration to realise a hybrid cutting process of bio-tissues. The study is based on a combination of advanced experimental and numerical (finite-element) studies of multi-body dynamics of a cutting system. The quality of cut samples produced with the prototype is compared with the state-of-the-art.

Effect of Biocompatible Peritoneal Dialysis Solution on Residual Renal Function: A Systematic Review of Randomized Controlled Trials

PubMed Central

Seo, Eun-Young; An, Sook Hee; Cho, Jang-Hee; Suh, Hae Sun; Park, Sun-Hee; Gwak, Hyesun; Kim, Yong-Lim; Ha, Hunjoo

2014-01-01

♦ Introduction: Residual renal function (RRF) plays an important role in outcome of peritoneal dialysis (PD) including mortality. It is, therefore, important to provide a strategy for the preservation of RRF. The objective of this study was to evaluate relative protective effects of new glucose-based multicompartmental PD solution (PDS), which is well known to be more biocompatible than glucose-based conventional PDS, on RRF compared to conventional PDS by performing a systematic review (SR) of randomized controlled trials. ♦ Methods: We searched studies presented up to January 2014 in MEDLINE, EMBASE, the COCHRANE library, and local databases. Three independent reviewers reviewed and extracted prespecified data from each study. The random effects model, a more conservative analysis model, was used to combine trials and to perform stratified analyses based on the duration of follow-up. Study quality was assessed using the Cochrane Handbook for risk of bias. Eleven articles with 1,034 patients were identified for the SR. ♦ Results: The heterogeneity of the studies under 12 months was very high, and the heterogeneity decreased substantially when we stratified studies by the duration of follow-up. The mean difference of the studies after 12 months was 0.46 mL/min/1.73 m2 (95% confidence interval = 0.25 to + 0.67). ♦ Conclusion: New PDS showed the effect to preserve and improve RRF for long-term use compared to conventional PDS, even though it did not show a significant difference to preserve RRF for short-term use. PMID:25185015

Predictive Accuracy of the Liverpool Lung Project Risk Model for Stratifying Patients for Computed Tomography Screening for Lung Cancer

PubMed Central

Raji, Olaide Y.; Duffy, Stephen W.; Agbaje, Olorunshola F.; Baker, Stuart G.; Christiani, David C.; Cassidy, Adrian; Field, John K.

2013-01-01

Background External validation of existing lung cancer risk prediction models is limited. Using such models in clinical practice to guide the referral of patients for computed tomography (CT) screening for lung cancer depends on external validation and evidence of predicted clinical benefit. Objective To evaluate the discrimination of the Liverpool Lung Project (LLP) risk model and demonstrate its predicted benefit for stratifying patients for CT screening by using data from 3 independent studies from Europe and North America. Design Case–control and prospective cohort study. Setting Europe and North America. Patients Participants in the European Early Lung Cancer (EUELC) and Harvard case–control studies and the LLP population-based prospective cohort (LLPC) study. Measurements 5-year absolute risks for lung cancer predicted by the LLP model. Results The LLP risk model had good discrimination in both the Harvard (area under the receiver-operating characteristic curve [AUC], 0.76 [95% CI, 0.75 to 0.78]) and the LLPC (AUC, 0.82 [CI, 0.80 to 0.85]) studies and modest discrimination in the EUELC (AUC, 0.67 [CI, 0.64 to 0.69]) study. The decision utility analysis, which incorporates the harms and benefit of using a risk model to make clinical decisions, indicates that the LLP risk model performed better than smoking duration or family history alone in stratifying high-risk patients for lung cancer CT screening. Limitations The model cannot assess whether including other risk factors, such as lung function or genetic markers, would improve accuracy. Lack of information on asbestos exposure in the LLPC limited the ability to validate the complete LLP risk model. Conclusion Validation of the LLP risk model in 3 independent external data sets demonstrated good discrimination and evidence of predicted benefits for stratifying patients for lung cancer CT screening. Further studies are needed to prospectively evaluate model performance and evaluate the optimal population risk thresholds for initiating lung cancer screening. Primary Funding Source Roy Castle Lung Cancer Foundation. PMID:22910935

Modeling abundance using multinomial N-mixture models

USGS Publications Warehouse

Royle, Andy

2016-01-01

Multinomial N-mixture models are a generalization of the binomial N-mixture models described in Chapter 6 to allow for more complex and informative sampling protocols beyond simple counts. Many commonly used protocols such as multiple observer sampling, removal sampling, and capture-recapture produce a multivariate count frequency that has a multinomial distribution and for which multinomial N-mixture models can be developed. Such protocols typically result in more precise estimates than binomial mixture models because they provide direct information about parameters of the observation process. We demonstrate the analysis of these models in BUGS using several distinct formulations that afford great flexibility in the types of models that can be developed, and we demonstrate likelihood analysis using the unmarked package. Spatially stratified capture-recapture models are one class of models that fall into the multinomial N-mixture framework, and we discuss analysis of stratified versions of classical models such as model Mb, Mh and other classes of models that are only possible to describe within the multinomial N-mixture framework.

Chronological record of environmental chemicals from analysis of stratified vertebrate excretion deposited in a sheltered environment

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

Petit, M.G.; Altenbach, J.S.

1973-01-01

Guano deposits of the migratory free-tailed bat Tadarida brasiliensis are stratified into distinguishable annual layers in some caves in the American Southwest. These layers may be dated and analyzed for environmental chemicals thus providing a chronological record of selected chemicals in the food chain of this mammal. It is found that the annual Hg fluctuations observed in the guano correlate with annual production figures of a nearby copper smelter. Analysis of the terms in a mathematical model suggests that the major mechanism by which smelter mercury enters the bat's food chain is dry fallout. A 1-yr delay time between peaksmore » and dips in industrial output and peaks and dips in the mercury present in guano indicate that industrial mercury is ingested by the bat indirectly via the food chain. The preliminary data presented here indicate that analysis of old deposits (preindustrial revolution) will provide baseline data for environmental chemicals.« less

Identifying molecular features for prostate cancer with Gleason 7 based on microarray gene expression profiles.

PubMed

Bălăcescu, Loredana; Bălăcescu, O; Crişan, N; Fetica, B; Petruţ, B; Bungărdean, Cătălina; Rus, Meda; Tudoran, Oana; Meurice, G; Irimie, Al; Dragoş, N; Berindan-Neagoe, Ioana

2011-01-01

Prostate cancer represents the first leading cause of cancer among western male population, with different clinical behavior ranging from indolent to metastatic disease. Although many molecules and deregulated pathways are known, the molecular mechanisms involved in the development of prostate cancer are not fully understood. The aim of this study was to explore the molecular variation underlying the prostate cancer, based on microarray analysis and bioinformatics approaches. Normal and prostate cancer tissues were collected by macrodissection from prostatectomy pieces. All prostate cancer specimens used in our study were Gleason score 7. Gene expression microarray (Agilent Technologies) was used for Whole Human Genome evaluation. The bioinformatics and functional analysis were based on Limma and Ingenuity software. The microarray analysis identified 1119 differentially expressed genes between prostate cancer and normal prostate, which were up- or down-regulated at least 2-fold. P-values were adjusted for multiple testing using Benjamini-Hochberg method with a false discovery rate of 0.01. These genes were analyzed with Ingenuity Pathway Analysis software and were established 23 genetic networks. Our microarray results provide new information regarding the molecular networks in prostate cancer stratified as Gleason 7. These data highlighted gene expression profiles for better understanding of prostate cancer progression.

Effect of gravity modulation on thermosolutal convection in an infinite layer of fluid

NASA Astrophysics Data System (ADS)

Saunders, B. V.; Murray, B. T.; McFadden, G. B.; Coriell, S. R.; Wheeler, A. A.

1991-10-01

The effect of time-periodic vertical gravity modulation on the onset of thermosolutal convection in an infinite horizontal layer with stress free boundaries is studied using Floquet theory for the linear stability analysis. Situations are considered for which the fluid layer is stably stratified in either the fingering or diffusive regimes of double diffusive convection. Results are presented both with and without steady background acceleration. Modulation may stabilize an unstable base solution or destabilize a stable base solution. In addition to synchronous and subharmonic response to the modulation frequency, instability in the double diffusive system can occur via a complex conjugate mode. In the diffusive regime, where oscillatory onset occurs in the unmodulated system, regions of resonant instability occur and exhibit strong coupling with the unmodulated oscillatory frequency.

Effect of PR interval prolongation on long-term outcomes in patients with left bundle branch block vs non-left bundle branch block morphologies undergoing cardiac resynchronization therapy.

PubMed

Rickard, John; Karim, Mohammad; Baranowski, Bryan; Cantillon, Daniel; Spragg, David; Tang, W H Wilson; Niebauer, Mark; Grimm, Richard; Trulock, Kevin; Wilkoff, Bruce; Varma, Niraj

2017-10-01

Although the influence of QRS duration (QRSd) and/or bundle branch block morphology on outcomes of cardiac resynchronization therapy (CRT) have been well studied, the effect of PR interval remains uncertain. The purpose of this study was to evaluate the impact of PR prolongation (PRp) before CRT on long-term outcomes, specifically taking into account bundle branch block morphology and QRSd. We extracted clinical data on consecutive patients undergoing CRT. Multivariate models were constructed to analyze the effect of PRp (≥200 ms) on the combined endpoint of death, heart transplant, or left ventricular assist device. Kaplan-Meier curves were constructed stratifying patients based on bundle branch block and QRSd (dichotomized by 150 ms). Of the 472 patients who met inclusion criteria, 197 (41.7%) had PR interval ≥200 ms. During follow-up (mean 5.1 ± 2.6 years) there were 214 endpoints, of which 109 (23.1%) occurred in patients with PRp. In multivariate analysis, PRp was independently associated with worsened outcomes (hazard ratio 1.34, 95% confidence interval 1.01-1.77, P = .04). When stratified by bundle branch block morphology, PRp was significantly associated with worsened outcomes (log-rank P <.001) in patients with LBBB but not in those with non-LBBB (log-rank P = .55). Among patients with LBBB, stratified by QRSd, patients without PRp had improved outcomes compared to those with PRp independent of QRSd (log-rank P <.001). PRp is an independent predictor of impaired long-term outcome after CRT among patients with LBBB but not in non-LBBB patients. Notably, among LBBB patients, PRp is a more important predictor than QRSd in assessing long-term outcomes. Copyright © 2017. Published by Elsevier Inc.

Environmental Transitions Recorded by Fluvial Fan Stratigraphy at Dingo Gap and Moonlight Valley, Gale Crater, Mars

NASA Astrophysics Data System (ADS)

Edgar, L. A.; Gupta, S.; Rubin, D. M.; Schieber, J.; Stack, K.; Lewis, K. W.

2016-12-01

The Mars Science Laboratory (MSL) Curiosity rover investigated a number of sedimentary outcrops across Aeolis Palus. Observations of conglomerates, cross-bedded sandstones, and mudstones suggest that fluvial and lacustrine environments were common. Outcrops that expose cross-sections are particularly helpful for identifying stratigraphic relationships and changes through time. In the vicinity of an outcrop informally named Dingo Gap, the drive strategy shifted from driving on the topographic high areas to the topographic low areas, which resulted in a unique vantage point to observe stratigraphy in cross-section. During Sols 513-541, Curiosity investigated 4 m of stratigraphy exposed at Dingo Gap and Moonlight Valley. The valley walls reveal five distinct sedimentary facies, including 1) a fine-grained evenly laminated facies interpreted as upper plane bed stratification, 2) ripple and dune cross-stratified sandstone facies, interpreted to represent the southward migration of subaqueous bedforms, 3) fully preserved bedform sandstone facies, formed during high rates of deposition, 4) planar-bedded granule-rich sandstone facies, interpreted as sheet flood deposits, and 5) a weakly stratified, poorly-sorted conglomerate facies, interpreted to represent rapid deposition from a high-energy fluvial flow. The conglomerate facies is unlike other conglomerates observed thus far in the mission, on the basis of both texture and chemistry. Analysis of conglomerates reveal that they occur as distinct channel bodies, incised into cross-stratified sandstones. This coarsening upward signature is interpreted to record a prograding fan succession. Channel bodies appear to be time-equivalent, which suggests a major change in the system, likely associated with a drop in base level. The unique viewing geometry offered by Dingo Gap and Moonlight Valley makes it possible to observe these environmental changes.

Layering of sustained vortices in rotating stratified fluids

NASA Astrophysics Data System (ADS)

Aubert, O.; Le Bars, M.; Le Gal, P.

2013-05-01

The ocean is a natural stratified fluid layer where large structures are influenced by the rotation of the planet through the Coriolis force. In particular, the ocean Meddies are long-lived anticyclonic pancake vortices of Mediterranean origin evolving in the Atlantic Ocean: they have a saltier and warmer core than the sourrounding oceanic water, their diameters go up to 100 km and they can survive for 2 to 3 years in the ocean. Their extensive study using seismic images revealed finestructures surrounding their core (Biescas et al., 2008; Ruddick et al., 2009) corresponding to layers of constant density which thickness is about 40 m and horizontal extent is more than 10 km. These layers can have different origins: salt fingers from a double-diffusive instabilities of salt and heat (Ruddick & Gargett, 2003), viscous overturning motions from a double-diffusive instabilities of salt and momentum (McIntyre, 1970) or global modes of the quasi-geostrophic instability (Nguyen et al., 2011)? As observed by Griffiths & Linden (1981), sustained laboratory anticyclonic vortices created via a continuous injection of isodense fluid in a rotating and linearly stratified layer of salty water are quickly surrounded by layers of constant density. In the continuity of their experiments, we systematically investigated the double-diffusive instability of McIntyre by varying the Coriolis parameter f and the buoyancy frequency N of the background both in experiments and in numerical simulations, and studied the influence of the Schmidt number in numerical simulations. Following McIntyre's approach, typical length and time scales of the instability are well described by a linear stability analysis based on a gaussian model that fits both laboratory and oceanic vortices. The instability appears to be favoured by high Rossby numbers and ratios f/N. We then apply these results to ocean Meddies and conclude about their stability.

Anatomy of small-scale mixing along a Northeast Atlantic transect

NASA Astrophysics Data System (ADS)

Jurado, Elena; Dijkstra, Henk A.; van der Woerd, Hans; Brussaard, Corina

2010-05-01

The study of turbulence occurring at the smallest scales, in the energy dissipation range, is required when evaluating interrelations between turbulent mixing and phytoplankton distribution. To derive microturbulent parameters, microstructure profiler surveys, consisting in high resolution temperature, salinity or velocity vertical profiles have been performed in localized regions of the open ocean. However, they are very localized and based on few datasets, difficult to extrapolate to other regions due to the dependence on the local background conditions. During the STRATIPHYT-I cruise (July-August 2009) from Las Palmas (Gran Canaria) to Reykjavik (Iceland), high resolution measurements of both turbulent mixing (with a Self Contained Autonomous Micro Profiler, SCAMP) and phytoplankton have been carried out in the top 100 m of the ocean. With these data, the gradient from a more stratified, warmer surface water tropical environment to a less stratified subpolar ocean environment is covered. Adding up a total of 15 stations and 148 profiles, it constitutes the most extensive dataset of directly derived vertical mixing coefficients in a latitudinal transect of the Northeast Atlantic. In the presentation, the focus is on the explanation of the changes in turbulent mixing along the cruise section, recalling in its latitudinal gradient and presenting parameters that can further help to evaluate effects in the phytoplankton distribution. Side issues such as the encountered disagreement between heat and density eddy diffusivities and an analysis of the main source of instabilities through GOTM model and an internal wave analysis, are also treated in detail.

Extended Subadiabatic Layer in Simulations of Overshooting Convection

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

Käpylä, Petri J.; Arlt, Rainer; Rheinhardt, Matthias

2017-08-20

We present numerical simulations of hydrodynamic overshooting convection in local Cartesian domains. We find that a substantial fraction of the lower part of the convection zone (CZ) is stably stratified according to the Schwarzschild criterion while the enthalpy flux is outward directed. This occurs when the heat conduction profile at the bottom of the CZ is smoothly varying, based either on a Kramers-like opacity prescription as a function of temperature and density or a static profile of a similar shape. We show that the subadiabatic layer arises due to nonlocal energy transport by buoyantly driven downflows in the upper partsmore » of the CZ. Analysis of the force balance of the upflows and downflows confirms that convection is driven by cooling at the surface. We find that the commonly used prescription for the convective enthalpy flux being proportional to the negative entropy gradient does not hold in the stably stratified layers where the flux is positive. We demonstrate the existence of a non-gradient contribution to the enthalpy flux, which is estimated to be important throughout the convective layer. A quantitative analysis of downflows indicates a transition from a tree-like structure where smaller downdrafts merge into larger ones in the upper parts to a structure in the deeper parts where a height-independent number of strong downdrafts persist. This change of flow topology occurs when a substantial subadiabatic layer is present in the lower part of the CZ.« less

Risk factors associated with leptospirosis during an outbreak in Middle Andaman, India.

PubMed

Sugunan, A P; Vijayachari, P; Sharma, S; Roy, Subarna; Manickam, P; Natarajaseenivasan, K; Gupte, M D; Sehgal, S C

2009-07-01

Leptospirosis outbreaks occur frequently in North and South Andaman Islands but not in Middle Andaman. In 2002, an outbreak appeared in Middle Andaman for the first time. Although a study on risk factors was conducted in North Andaman, it used seropositivity to define leptospirosis. Since seropositivity might not indicate current leptospiral infection and as no study on risk factors was conducted in Middle Andaman, we carried out this study to identify the risk factors during the outbreak. A suspected outbreak of leptospirosis occurred in Rangat of Middle Andaman during October - November 2002. Suspected cases were screened for leptospirosis using microscopic agglutination test (MAT). Fifty two patients confirmed to have leptospirosis based on rising titres in MAT on paired sera, and 104 age, sex and neighbourhood seronegative matched controls, were included in the study. A conditional multiple regression by backward elimination process was carried out with acute leptospirosis as the dependent factor and various environmental, occupational and behavioural factors as independent factors. A stratified analysis was also carried out. The presence of cattle in the house, drinking stream water, contact with garbage, walking barefoot and standing in water while working were identified as significant factors associated with leptospirosis. Stratified analysis showed a dose response relationship between number of cattle in the house and the risk of leptospiral infection suugesting that cattle could be a source of infection. Identification of the potential risk factors would help understand the transmission dynamics of the disease and formulate public health interventions.

Nottingham Prognostic Index Plus (NPI+): a modern clinical decision making tool in breast cancer.

PubMed

Rakha, E A; Soria, D; Green, A R; Lemetre, C; Powe, D G; Nolan, C C; Garibaldi, J M; Ball, G; Ellis, I O

2014-04-02

Current management of breast cancer (BC) relies on risk stratification based on well-defined clinicopathologic factors. Global gene expression profiling studies have demonstrated that BC comprises distinct molecular classes with clinical relevance. In this study, we hypothesised that molecular features of BC are a key driver of tumour behaviour and when coupled with a novel and bespoke application of established clinicopathologic prognostic variables can predict both clinical outcome and relevant therapeutic options more accurately than existing methods. In the current study, a comprehensive panel of biomarkers with relevance to BC was applied to a large and well-characterised series of BC, using immunohistochemistry and different multivariate clustering techniques, to identify the key molecular classes. Subsequently, each class was further stratified using a set of well-defined prognostic clinicopathologic variables. These variables were combined in formulae to prognostically stratify different molecular classes, collectively known as the Nottingham Prognostic Index Plus (NPI+). The NPI+ was then used to predict outcome in the different molecular classes. Seven core molecular classes were identified using a selective panel of 10 biomarkers. Incorporation of clinicopathologic variables in a second-stage analysis resulted in identification of distinct prognostic groups within each molecular class (NPI+). Outcome analysis showed that using the bespoke NPI formulae for each biological BC class provides improved patient outcome stratification superior to the traditional NPI. This study provides proof-of-principle evidence for the use of NPI+ in supporting improved individualised clinical decision making.

Optimal spatial sampling techniques for ground truth data in microwave remote sensing of soil moisture

NASA Technical Reports Server (NTRS)

Rao, R. G. S.; Ulaby, F. T.

1977-01-01

The paper examines optimal sampling techniques for obtaining accurate spatial averages of soil moisture, at various depths and for cell sizes in the range 2.5-40 acres, with a minimum number of samples. Both simple random sampling and stratified sampling procedures are used to reach a set of recommended sample sizes for each depth and for each cell size. Major conclusions from statistical sampling test results are that (1) the number of samples required decreases with increasing depth; (2) when the total number of samples cannot be prespecified or the moisture in only one single layer is of interest, then a simple random sample procedure should be used which is based on the observed mean and SD for data from a single field; (3) when the total number of samples can be prespecified and the objective is to measure the soil moisture profile with depth, then stratified random sampling based on optimal allocation should be used; and (4) decreasing the sensor resolution cell size leads to fairly large decreases in samples sizes with stratified sampling procedures, whereas only a moderate decrease is obtained in simple random sampling procedures.

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

Rubin, H.; Bemporad, G.A.

The advanced solar pond (ASP) is characterized by having two thermal layers. The homogeneous thermal layer is adjacent to the pond bottom. On top of this layer a stratified thermal layer is located. One of the major advantages of the solar pond (SP) stems from its capability to store large quantities of thermal energy. In cases of excessive needs for thermal energy, the flow of the thermal layers may be subject to turbulent flow conditions. In this paper the effect of such conditions on transport phenomena in the ASP is analyzed. The analysis indicates that whereas the homogeneous thermal layermore » flows turbulently, the stratified thermal layer may be subject to laminar flow.« less

Development of a resource allocation formula for substance misuse treatment services.

PubMed

Jones, Andrew; Hayhurst, Karen P; Whittaker, Will; Mason, Thomas; Sutton, Matt

2017-11-23

Funding for substance misuse services comprises one-third of Public Health spend in England. The current allocation formula contains adjustments for actual activity, performance and need, proxied by the Standardized Mortality Ratio for under-75s (SMR < 75). Additional measures, such as deprivation, may better identify differential service need. We developed an age-standardized and an age-stratified model (over-18s, under-18s), with the outcome of expected/actual cost at postal sector/Local Authority level. A third, person-based model incorporated predictors of costs at the individual level. Each model incorporated both needs and supply variables, with the relative effects of their inclusion assessed. Mean estimated annual cost (2013/14) per English Local Authority area was £5 032 802 (sd: 3 951 158). Costs for drug misuse treatment represented the majority (83%) of costs. Models achieved adjusted R-squared values of 0.522 (age-standardized), 0.533 (age-stratified over-18s), 0.232 (age-stratified under-18s) and 0.470 (person-based). Improvements can be made to the existing resource allocation formulae to better reflect population need. The person-based model permits inclusion of a range of needs variables, in addition to strong predictors of cost based on the receipt of treatment in the previous year. Adoption of this revised person-based formula for substance misuse would shift resources towards more deprived areas. © The Author 2017. Published by Oxford University Press on behalf of Faculty of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

A stratified random survey of the proportion of poor quality oral artesunate sold at medicine outlets in the Lao PDR – implications for therapeutic failure and drug resistance

PubMed Central

Sengaloundeth, Sivong; Green, Michael D; Fernández, Facundo M; Manolin, Ot; Phommavong, Khamlieng; Insixiengmay, Vongsavanh; Hampton, Christina Y; Nyadong, Leonard; Mildenhall, Dallas C; Hostetler, Dana; Khounsaknalath, Lamphet; Vongsack, Latsamy; Phompida, Samlane; Vanisaveth, Viengxay; Syhakhang, Lamphone; Newton, Paul N

2009-01-01

Background Counterfeit oral artesunate has been a major public health problem in mainland SE Asia, impeding malaria control. A countrywide stratified random survey was performed to determine the availability and quality of oral artesunate in pharmacies and outlets (shops selling medicines) in the Lao PDR (Laos). Methods In 2003, 'mystery' shoppers were asked to buy artesunate tablets from 180 outlets in 12 of the 18 Lao provinces. Outlets were selected using stratified random sampling by investigators not involved in sampling. Samples were analysed for packaging characteristics, by the Fast Red Dye test, high-performance liquid chromatography (HPLC), mass spectrometry (MS), X-ray diffractometry and pollen analysis. Results Of 180 outlets sampled, 25 (13.9%) sold oral artesunate. Outlets selling artesunate were more commonly found in the more malarious southern Laos. Of the 25 outlets, 22 (88%; 95%CI 68–97%) sold counterfeit artesunate, as defined by packaging and chemistry. No artesunate was detected in the counterfeits by any of the chemical analysis techniques and analysis of the packaging demonstrated seven different counterfeit types. There was complete agreement between the Fast Red dye test, HPLC and MS analysis. A wide variety of wrong active ingredients were found by MS. Of great concern, 4/27 (14.8%) fakes contained detectable amounts of artemisinin (0.26–115.7 mg/tablet). Conclusion This random survey confirms results from previous convenience surveys that counterfeit artesunate is a severe public health problem. The presence of artemisinin in counterfeits may encourage malaria resistance to artemisinin derivatives. With increasing accessibility of artemisinin-derivative combination therapy (ACT) in Laos, the removal of artesunate monotherapy from pharmacies may be an effective intervention. PMID:19638225

A stratified random survey of the proportion of poor quality oral artesunate sold at medicine outlets in the Lao PDR - implications for therapeutic failure and drug resistance.

PubMed

Sengaloundeth, Sivong; Green, Michael D; Fernández, Facundo M; Manolin, Ot; Phommavong, Khamlieng; Insixiengmay, Vongsavanh; Hampton, Christina Y; Nyadong, Leonard; Mildenhall, Dallas C; Hostetler, Dana; Khounsaknalath, Lamphet; Vongsack, Latsamy; Phompida, Samlane; Vanisaveth, Viengxay; Syhakhang, Lamphone; Newton, Paul N

2009-07-28

Counterfeit oral artesunate has been a major public health problem in mainland SE Asia, impeding malaria control. A countrywide stratified random survey was performed to determine the availability and quality of oral artesunate in pharmacies and outlets (shops selling medicines) in the Lao PDR (Laos). In 2003, 'mystery' shoppers were asked to buy artesunate tablets from 180 outlets in 12 of the 18 Lao provinces. Outlets were selected using stratified random sampling by investigators not involved in sampling. Samples were analysed for packaging characteristics, by the Fast Red Dye test, high-performance liquid chromatography (HPLC), mass spectrometry (MS), X-ray diffractometry and pollen analysis. Of 180 outlets sampled, 25 (13.9%) sold oral artesunate. Outlets selling artesunate were more commonly found in the more malarious southern Laos. Of the 25 outlets, 22 (88%; 95%CI 68-97%) sold counterfeit artesunate, as defined by packaging and chemistry. No artesunate was detected in the counterfeits by any of the chemical analysis techniques and analysis of the packaging demonstrated seven different counterfeit types. There was complete agreement between the Fast Red dye test, HPLC and MS analysis. A wide variety of wrong active ingredients were found by MS. Of great concern, 4/27 (14.8%) fakes contained detectable amounts of artemisinin (0.26-115.7 mg/tablet). This random survey confirms results from previous convenience surveys that counterfeit artesunate is a severe public health problem. The presence of artemisinin in counterfeits may encourage malaria resistance to artemisinin derivatives. With increasing accessibility of artemisinin-derivative combination therapy (ACT) in Laos, the removal of artesunate monotherapy from pharmacies may be an effective intervention.

Stratified probabilistic bias analysis for BMI-related exposure misclassification in postmenopausal women.

PubMed

Banack, Hailey R; Stokes, Andrew; Fox, Matthew P; Hovey, Kathleen M; Cespedes-Feliciano, Elizabeth M; LeBlanc, Erin; Bird, Chloe; Caan, Bette J; Kroenke, Candyce H; Allison, Matthew A; Going, Scott B; Snetslaar, Linda; Cheng, Ting-Yuan David; Chlebowski, Rowan T; Stefanick, Marcia L; LaMonte, Michael J; Wactawski-Wende, Jean

2018-06-01

There is widespread concern about the use of body mass index (BMI) to define obesity status in postmenopausal women because it may not accurately represent an individual's true obesity status. The objective of the present study is to examine and adjust for exposure misclassification bias from using an indirect measure of obesity (BMI) compared with a direct measure of obesity (percent body fat). We used data from postmenopausal non-Hispanic black and non-Hispanic white women in the Women's Health Initiative (WHI; n=126,459). Within the WHI, a sample of 11,018 women were invited to participate in a sub-study involving dual-energy x-ray absorptiometry (DXA) scans. We examined indices of validity comparing BMI-defined obesity (≥30kg/m) with obesity defined by percent body fat. We then used probabilistic bias analysis models stratified by age and race to explore the effect of exposure misclassification on the obesity-mortality relationship. Validation analyses highlight that using a BMI cutpoint of 30 kg/m to define obesity in postmenopausal women is associated with poor validity. There were notable differences in sensitivity by age and race. Results from the stratified bias analysis demonstrated that failing to adjust for exposure misclassification bias results in attenuated estimates of the obesity-mortality relationship. For example, in non-Hispanic white women age 50-59, the conventional risk difference was 0.017 (95% CI 0.01, 0.023) and the bias-adjusted risk difference was 0.035 (95% SI 0.028, 0.043). These results demonstrate the importance of using quantitative bias analysis techniques to account for non-differential exposure misclassification of BMI-defined obesity.

Evaluation of different approaches for identifying optimal sites to predict mean hillslope soil moisture content

NASA Astrophysics Data System (ADS)

Liao, Kaihua; Zhou, Zhiwen; Lai, Xiaoming; Zhu, Qing; Feng, Huihui

2017-04-01

The identification of representative soil moisture sampling sites is important for the validation of remotely sensed mean soil moisture in a certain area and ground-based soil moisture measurements in catchment or hillslope hydrological studies. Numerous approaches have been developed to identify optimal sites for predicting mean soil moisture. Each method has certain advantages and disadvantages, but they have rarely been evaluated and compared. In our study, surface (0-20 cm) soil moisture data from January 2013 to March 2016 (a total of 43 sampling days) were collected at 77 sampling sites on a mixed land-use (tea and bamboo) hillslope in the hilly area of Taihu Lake Basin, China. A total of 10 methods (temporal stability (TS) analyses based on 2 indices, K-means clustering based on 6 kinds of inputs and 2 random sampling strategies) were evaluated for determining optimal sampling sites for mean soil moisture estimation. They were TS analyses based on the smallest index of temporal stability (ITS, a combination of the mean relative difference and standard deviation of relative difference (SDRD)) and based on the smallest SDRD, K-means clustering based on soil properties and terrain indices (EFs), repeated soil moisture measurements (Theta), EFs plus one-time soil moisture data (EFsTheta), and the principal components derived from EFs (EFs-PCA), Theta (Theta-PCA), and EFsTheta (EFsTheta-PCA), and global and stratified random sampling strategies. Results showed that the TS based on the smallest ITS was better (RMSE = 0.023 m3 m-3) than that based on the smallest SDRD (RMSE = 0.034 m3 m-3). The K-means clustering based on EFsTheta (-PCA) was better (RMSE <0.020 m3 m-3) than these based on EFs (-PCA) and Theta (-PCA). The sampling design stratified by the land use was more efficient than the global random method. Forty and 60 sampling sites are needed for stratified sampling and global sampling respectively to make their performances comparable to the best K-means method (EFsTheta-PCA). Overall, TS required only one site, but its accuracy was limited. The best K-means method required <8 sites and yielded high accuracy, but extra soil and terrain information is necessary when using this method. The stratified sampling strategy can only be used if no pre-knowledge about soil moisture variation is available. This information will help in selecting the optimal methods for estimation the area mean soil moisture.

Cardiorespiratory Fitness Levels among U.S. Youth Aged 12-15 Years: United States, 1999-2004 and 2012

MedlinePlus

... use a complex, stratified, multistage probability cluster sampling design. NHANES data collection is based on a nationally ... conjunction with the 2012 NHANES and the survey design was based on the design for NHANES, with ...

Education-stratified base-rate information on discrepancy scores within and between the Wechsler Adult Intelligence Scale--Third Edition and the Wechsler Memory Scale--Third Edition.

PubMed

Dori, Galit A; Chelune, Gordon J

2004-06-01

The Wechsler Adult Intelligence Scale--Third Edition (WAIS-III; D. Wechsler, 1997a) and the Wechsler Memory Scale--Third Edition (WMS-III; D. Wechsler, 1997b) are 2 of the most frequently used measures in psychology and neuropsychology. To facilitate the diagnostic use of these measures in the clinical decision-making process, this article provides information on education-stratified, directional prevalence rates (i.e., base rates) of discrepancy scores between the major index scores for the WAIS-III, the WMS-III, and between the WAIS-III and WMS-III. To illustrate how such base-rate data can be clinically used, this article reviews the relative risk (i.e., odds ratio) of empirically defined "rare" cognitive deficits in 2 of the clinical samples presented in the WAIS-III--WMS-III Technical Manual (The Psychological Corporation, 1997). ((c) 2004 APA, all rights reserved)

Acculturation, gender, and mental health of Southeast Asian immigrant youth in Canada.

PubMed

Hilario, Carla T; Vo, Dzung X; Johnson, Joy L; Saewyc, Elizabeth M

2014-12-01

The relationships between mental health, protective factors and acculturation among Southeast Asian youth were examined in this study using a gender-based analysis. Population-based data from the 2008 British Columbia Adolescent Health Survey were used to examine differences in extreme stress and despair by acculturation. Associations between emotional distress and hypothesized protective factors were examined using logistic regression. Stratified analyses were performed to assess gender-related differences. Recent immigrant youth reported higher odds of emotional distress. Family connectedness and school connectedness were linked to lower odds of extreme stress and despair among girls. Family connectedness was associated with lower odds of extreme stress and despair among boys. Higher cultural connectedness was associated with lower odds of despair among boys but with higher odds of extreme stress among girls. Findings are discussed in relation to acculturation and gender-based patterns in protective factors for mental health among Southeast Asian immigrant youth.

Impact of asian ethnicity on colorectal cancer screening: a population-based analysis.

PubMed

Homayoon, Babak; Shahidi, Neal C; Cheung, Winson Y

2013-04-01

Although research shows that African Americans and Hispanics frequently receive less colorectal cancer screening (CRCS) than whites, few studies have focused on CRCS among Asians. The aims of this study were to compare CRCS between Asians and whites and to evaluate for clinical predictors of CRCS. From the 2007 California Health Interview Survey, we identified all Asian and white respondents who were eligible for CRCS. Logistic regression was performed to evaluate for differences in CRCS. We used stratified and interaction analyses to examine whether associations between race and CRCS were modified by insurance status, birthplace, or language skills, while controlling for other confounders. Baseline characteristics were similar between Asians and whites. Only 58% of Asians and 66% of whites reported undergoing up-to-date CRCS (P < 0.01). In multivariate analyses, visiting a physician more than 5 times produced the highest odds of being up-to-date with screening. When compared with whites, Asians had decreased odds of being up-to-date with screening. Stratified analyses showed that this disparity existed mainly in the insured, but not in the uninsured, and it was not modified by place of birth or English language proficiency. Despite its ability to reduce mortality, CRCS is suboptimal in our US population-based cohort of Asians when compared with whites. A contributing factor to this problem for the Chinese and Koreans may be a lack of awareness regarding CRCS, whereas the source of the problem in the Vietnamese seems to be related to healthcare access.

Modelling the distribution of domestic ducks in Monsoon Asia

USGS Publications Warehouse

Van Bockel, Thomas P.; Prosser, Diann; Franceschini, Gianluca; Biradar, Chandra; Wint, William; Robinson, Tim; Gilbert, Marius

2011-01-01

Domestic ducks are considered to be an important reservoir of highly pathogenic avian influenza (HPAI), as shown by a number of geospatial studies in which they have been identified as a significant risk factor associated with disease presence. Despite their importance in HPAI epidemiology, their large-scale distribution in Monsoon Asia is poorly understood. In this study, we created a spatial database of domestic duck census data in Asia and used it to train statistical distribution models for domestic duck distributions at a spatial resolution of 1km. The method was based on a modelling framework used by the Food and Agriculture Organisation to produce the Gridded Livestock of the World (GLW) database, and relies on stratified regression models between domestic duck densities and a set of agro-ecological explanatory variables. We evaluated different ways of stratifying the analysis and of combining the prediction to optimize the goodness of fit of the predictions. We found that domestic duck density could be predicted with reasonable accuracy (mean RMSE and correlation coefficient between log-transformed observed and predicted densities being 0.58 and 0.80, respectively), using a stratification based on livestock production systems. We tested the use of artificially degraded data on duck distributions in Thailand and Vietnam as training data, and compared the modelled outputs with the original high-resolution data. This showed, for these two countries at least, that these approaches could be used to accurately disaggregate provincial level (administrative level 1) statistical data to provide high resolution model distributions.

Cerebrovascular accidents in patients treated for choroidal neovascularization with ranibizumab in randomized controlled trials.

PubMed

Bressler, Neil M; Boyer, David S; Williams, David F; Butler, Steven; Francom, Steven F; Brown, Benton; Di Nucci, Flavia; Cramm, Timothy; Tuomi, Lisa L; Ianchulev, Tsontcho; Rubio, Roman G

2012-10-01

To analyze cerebrovascular accidents (CVAs) pooled from large, randomized, controlled clinical trials of ranibizumab treatment for neovascular age-related macular degeneration. Events in five trials (FOCUS, MARINA, ANCHOR, PIER, and SAILOR) were analyzed using a standard safety monitoring process. Exact methods, stratified by study, were used to test for treatment differences based on odds ratios. A stepwise logistic regression model was fit to classify subjects' risk for CVA based on medical history. Treatment differences in CVA rates at 1 year or 2 years were evaluated within risk groups using stratified exact methods. Pooled 2-year CVA rates were <3%; odds ratios (95% confidence intervals) for CVA risk were 1.2 (0.4-4.4) for ranibizumab 0.3-mg versus control, 2.2 (0.8-7.1) for 0.5 mg versus control, and 1.5 (0.8-3.0) for 0.5-mg versus 0.3-mg ranibizumab. No substantial increased risk of CVA for 0.5 mg versus 0.3 mg was identified in pooled analyses or any of the individual trials. In pooled analyses, the difference between 0.5-mg ranibizumab and control was larger (7.7 [1.2-177]) among high-risk CVA patients. This analysis provided some evidence, although not definitive, of a potential increased risk of CVA with ranibizumab versus control or with 0.5-mg versus 0.3-mg ranibizumab. Continued monitoring for CVA within clinical trials seems warrented.

Landsat image and sample design for water reservoirs (Rapel dam Central Chile).

PubMed

Lavanderos, L; Pozo, M E; Pattillo, C; Miranda, H

1990-01-01

Spatial heterogeneity of the Rapel reservoir surface waters is analyzed through Landsat images. The image digital counts are used with the aim or developing an aprioristic quantitative sample design.Natural horizontal stratification of the Rapel Reservoir (Central Chile) is produced mainly by suspended solids. The spatial heterogeneity conditions of the reservoir for the Spring 86-Summer 87 period were determined by qualitative analysis and image processing of the MSS Landsat, bands 1 and 3. The space-time variations of the different observed strata obtained with multitemporal image analysis.A random stratified sample design (r.s.s.d) was developed, based on the digital counts statistical analysis. Strata population size as well as the average, variance and sampling size of the digital counts were obtained by the r.s.s.d method.Stratification determined by analysis of satellite images were later correlated with ground data. Though the stratification of the reservoir is constant over time, the shape and size of the strata varys.

Performance of FDG-PET/CT in solitary pulmonary nodule based on pre-test likelihood of malignancy: results from the ITALIAN retrospective multicenter trial.

PubMed

Evangelista, Laura; Cuocolo, Alberto; Pace, Leonardo; Mansi, Luigi; Del Vecchio, Silvana; Miletto, Paolo; Sanfilippo, Silvia; Pellegrino, Sara; Guerra, Luca; Pepe, Giovanna; Peluso, Giuseppina; Salvatore, Marco; Galicchio, Rosj; Zuffante, Michele; Annunziata, Salvatore; Farsad, Mohsen; Chiaravalloti, Agostino; Spadafora, Marco

2018-05-07

The aim of this study was to determine the performance of 18 F-FDG-PET/CT in patients with solitary pulmonary nodule (SPN), stratifying the risk according to the likelihood of pulmonary malignancy. FDG-PET/CT of 502 patients, stratified for pre-test cancer risk, were retrospectively analyzed. FDG uptake in SPN was assessed by a 4-point scoring system and semiquantitative analysis using the ratio between SUVmax in SPN and SUVmean in mediastinal blood pool (BP) and between SUVmax in SPN and SUVmean in liver (L). Histopathology and/or follow-up data were used as standard of reference. SPN was malignant in 180 (36%) patients, benign in 175 (35%), and indeterminate in 147 (29%). The 355 patients with a definitive SPN nature (malignant or benign) were considered for the analysis. Considering FDG uptake ≥ 2, sensitivity, specificity, positive (PPV) and negative (NPV) predictive values, and accuracy were 85.6%, 85.7%, 86%, 85.2%, and 85.6% respectively. Sensitivity and PPV were higher (P < 0.05) in intermediate and high-risk patients, while specificity and NPV were higher (P < 0.05) in low-risk patients. On receiver operating characteristic curve analysis, the cut-offs for better discrimination between benign and malignant SPN were 1.56 (sensitivity 81% and specificity 87%) and 1.12 (sensitivity 81% and specificity 86%) for SUVmax/SUVmeanBP and SUVmax/SUVmeanL respectively. In intermediate and high-risk patients, including the SUVmax/SUVmeanBP, the specificity shifted from 85% and 50% to 100%. Visual FDG-PET/CT has an acceptable performance in patients with SPN, but accuracy improves when SUVratios are considered, particularly in patients with intermediate and high risk of malignancy.

Familial intracranial aneurysms: is anatomic vulnerability heritable?

PubMed

Mackey, Jason; Brown, Robert D; Moomaw, Charles J; Hornung, Richard; Sauerbeck, Laura; Woo, Daniel; Foroud, Tatiana; Gandhi, Dheeraj; Kleindorfer, Dawn; Flaherty, Matthew L; Meissner, Irene; Anderson, Craig; Rouleau, Guy; Connolly, E Sander; Deka, Ranjan; Koller, Daniel L; Abruzzo, Todd; Huston, John; Broderick, Joseph P

2013-01-01

Previous studies have suggested that family members with intracranial aneurysms (IAs) often harbor IAs in similar anatomic locations. IA location is important because of its association with rupture. We tested the hypothesis that anatomic susceptibility to IA location exists using a family-based IA study. We identified all affected probands and first-degree relatives (FDRs) with a definite or probable phenotype in each family. We stratified each IA of the probands by major arterial territory and calculated each family's proband-FDR territory concordance and overall contribution to the concordance analysis. We then matched each family unit to an unrelated family unit selected randomly with replacement and performed 1001 simulations. The median concordance proportions, odds ratios (ORs), and P values from the 1001 logistic regression analyses were used to represent the final results of the analysis. There were 323 family units available for analysis, including 323 probands and 448 FDRs, with a total of 1176 IAs. IA territorial concordance was higher in the internal carotid artery (55.4% versus 45.6%; OR, 1.54 [1.04-2.27]; P=0.032), middle cerebral artery (45.8% versus 30.5%; OR, 1.99 [1.22-3.22]; P=0.006), and vertebrobasilar system (26.6% versus 11.3%; OR, 2.90 [1.05-8.24], P=0.04) distributions in the true family compared with the comparison family. Concordance was also higher when any location was considered (53.0% versus 40.7%; OR, 1.82 [1.34-2.46]; P<0.001). In a highly enriched sample with familial predisposition to IA development, we found that IA territorial concordance was higher when probands were compared with their own affected FDRs than with comparison FDRs, which suggests that anatomic vulnerability to IA formation exists. Future studies of IA genetics should consider stratifying cases by IA location.

How Big of a Problem is Analytic Error in Secondary Analyses of Survey Data?

PubMed

West, Brady T; Sakshaug, Joseph W; Aurelien, Guy Alain S

2016-01-01

Secondary analyses of survey data collected from large probability samples of persons or establishments further scientific progress in many fields. The complex design features of these samples improve data collection efficiency, but also require analysts to account for these features when conducting analysis. Unfortunately, many secondary analysts from fields outside of statistics, biostatistics, and survey methodology do not have adequate training in this area, and as a result may apply incorrect statistical methods when analyzing these survey data sets. This in turn could lead to the publication of incorrect inferences based on the survey data that effectively negate the resources dedicated to these surveys. In this article, we build on the results of a preliminary meta-analysis of 100 peer-reviewed journal articles presenting analyses of data from a variety of national health surveys, which suggested that analytic errors may be extremely prevalent in these types of investigations. We first perform a meta-analysis of a stratified random sample of 145 additional research products analyzing survey data from the Scientists and Engineers Statistical Data System (SESTAT), which describes features of the U.S. Science and Engineering workforce, and examine trends in the prevalence of analytic error across the decades used to stratify the sample. We once again find that analytic errors appear to be quite prevalent in these studies. Next, we present several example analyses of real SESTAT data, and demonstrate that a failure to perform these analyses correctly can result in substantially biased estimates with standard errors that do not adequately reflect complex sample design features. Collectively, the results of this investigation suggest that reviewers of this type of research need to pay much closer attention to the analytic methods employed by researchers attempting to publish or present secondary analyses of survey data.

How Big of a Problem is Analytic Error in Secondary Analyses of Survey Data?

PubMed Central

West, Brady T.; Sakshaug, Joseph W.; Aurelien, Guy Alain S.

2016-01-01

Secondary analyses of survey data collected from large probability samples of persons or establishments further scientific progress in many fields. The complex design features of these samples improve data collection efficiency, but also require analysts to account for these features when conducting analysis. Unfortunately, many secondary analysts from fields outside of statistics, biostatistics, and survey methodology do not have adequate training in this area, and as a result may apply incorrect statistical methods when analyzing these survey data sets. This in turn could lead to the publication of incorrect inferences based on the survey data that effectively negate the resources dedicated to these surveys. In this article, we build on the results of a preliminary meta-analysis of 100 peer-reviewed journal articles presenting analyses of data from a variety of national health surveys, which suggested that analytic errors may be extremely prevalent in these types of investigations. We first perform a meta-analysis of a stratified random sample of 145 additional research products analyzing survey data from the Scientists and Engineers Statistical Data System (SESTAT), which describes features of the U.S. Science and Engineering workforce, and examine trends in the prevalence of analytic error across the decades used to stratify the sample. We once again find that analytic errors appear to be quite prevalent in these studies. Next, we present several example analyses of real SESTAT data, and demonstrate that a failure to perform these analyses correctly can result in substantially biased estimates with standard errors that do not adequately reflect complex sample design features. Collectively, the results of this investigation suggest that reviewers of this type of research need to pay much closer attention to the analytic methods employed by researchers attempting to publish or present secondary analyses of survey data. PMID:27355817

Impact of a decision aid about stratified ovarian cancer risk-management on women's knowledge and intentions: a randomised online experimental survey study.

PubMed

Meisel, Susanne F; Freeman, Maddie; Waller, Jo; Fraser, Lindsay; Gessler, Sue; Jacobs, Ian; Kalsi, Jatinderpal; Manchanda, Ranjit; Rahman, Belinda; Side, Lucy; Wardle, Jane; Lanceley, Anne; Sanderson, Saskia C

2017-11-16

Risk stratification using genetic and other types of personal information could improve current best available approaches to ovarian cancer risk reduction, improving identification of women at increased risk of ovarian cancer and reducing unnecessary interventions for women at lower risk. Amounts of information given to women may influence key informed decision-related outcomes, e.g. knowledge. The primary aim of this study was to compare informed decision-related outcomes between women given one of two versions (gist vs. extended) of a decision aid about stratified ovarian cancer risk-management. This was an experimental survey study comparing the effects of brief (gist) information with lengthier, more detailed (extended) information on cognitions relevant to informed decision-making about participating in risk-stratified ovarian cancer screening. Women with no personal history of ovarian cancer were recruited through an online survey company and randomised to view the gist (n = 512) or extended (n = 519) version of a website-based decision aid and completed an online survey. Primary outcomes were knowledge and intentions. Secondary outcomes included attitudes (values) and decisional conflict. There were no significant differences between the gist and extended conditions in knowledge about ovarian cancer (time*group interaction: F = 0.20, p = 0.66) or intention to participate in ovarian cancer screening based on genetic risk assessment (t(1029) = 0.43, p = 0.67). There were also no between-groups differences in secondary outcomes. In the sample overall (n = 1031), knowledge about ovarian cancer increased from before to after exposure to the decision aid (from 5.71 to 6.77 out of a possible 10: t = 19.04, p < 0.001), and 74% of participants said that they would participate in ovarian cancer screening based on genetic risk assessment. No differences in knowledge or intentions were found between women who viewed the gist version and women who viewed the extended version of a decision aid about risk-stratified ovarian cancer screening. Knowledge increased for women in both decision aid groups. Further research is needed to determine the ideal volume and type of content for decision aids about stratified ovarian cancer risk-management. This study was registered with the ISRCTN registry; registration number: ISRCTN48627877 .

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.

Atmospheric surface and boundary layers of the Amazon Basin

NASA Technical Reports Server (NTRS)

Garstang, Michael

1987-01-01

Three phases of work were performed: design of and preparation for the Amazon Boundary Layer Experiment (ABLE 2-A); execution of the ABLE 2-A field program; and analysis of the ABLE 2-A data. Three areas of experiment design were dealt with: surface based meteorological measurements; aircraft missions; and project meteorological support. The primary goal was to obtain a good description of the structure of the atmosphere immediately above the rain forest canopy (top of canopy to a few thousand meters), to describe this region during the growing daytime phase of the boundary layer; and to examine the nighttime stratified state. A secondary objective was to examine the role that deep convective storms play in the vertical transport of heat, water vapor, and other trace gases. While significant progress was made, much of the analysis remains to be done.

Intra-Group Motivational Analysis of Students with Learning Disabilities: A Goal Orientation Approach

ERIC Educational Resources Information Center

Sideris, Georgios D.; Tsorbatzoudis, Charalambos

2003-01-01

The purpose of the present study was to profile, using a K-means cluster analysis, the cognitive, motivational, affective, and goal orientation characteristics of elementary school students with and without learning disabilities (LD). Participants were 58 fifth and 6 sixth graders (29 typical and 29 LD) selected using stratified random procedures.…

Antiviral Therapy in Steroid-refractory Ulcerative Colitis with Cytomegalovirus: Systematic Review and Meta-analysis.

PubMed

Shukla, Tushar; Singh, Siddharth; Loftus, Edward V; Bruining, David H; McCurdy, Jeffrey D

2015-11-01

The role of antiviral therapy in patients with ulcerative colitis (UC) with cytomegalovirus (CMV) remains unclear. We therefore performed a systematic review and meta-analysis to assess the association between antiviral therapy and the risk of colectomy. Multiple electronic databases were searched systematically through July 2014 for studies reporting the risk of colectomy in patients with UC with CMV stratified by treatment with antiviral agents. Colectomy rates were assessed for the overall cohort and stratified by corticosteroid (CS) refractoriness. We estimated summary odds ratios and 95% confidence intervals, using random-effects model, and used Grading of Recommendations Assessment, Development, and Evaluation criteria to appraise the quality of evidence. Fifteen observational studies (333 patients with UC with CMV, 43.2% treated with antiviral agents) were identified, of which 8 stratified patients according to CS-refractory disease (55.4% treated with antiviral agents). Antiviral therapy resulted in a significantly lower risk of colectomy in patients with CS-refractory disease (odds ratio, 0.20; 95% confidence interval, 0.08-0.49; I = 0%) but not in the overall population of patients with UC (odds ratio, 0.92; 95% confidence interval, 0.31-2.76; I = 65). The quality evidence was low. The results were stable when restricting the analysis to patients with a tissue diagnosis of CMV and studies that defined CS-refractory disease as a failure to respond to intravenous CS. Antiviral therapy may benefit a subgroup of patients with UC who are refractory to CS. Further prospective trials are required to confirm these findings.

Sensitivity of the Geomagnetic Octupole to a Stably Stratified Layer in the Earth's Core

NASA Astrophysics Data System (ADS)

Yan, C.; Stanley, S.

2017-12-01

The presence of a stably stratified layer at the top of the core has long been proposed for Earth, based on evidence from seismology and geomagnetic secular variation. Geodynamo modeling offers a unique window to inspect the properties and dynamics in Earth's core. For example, numerical simulations have shown that magnetic field morphology is sensitive to the presence of stably stratified layers in a planet's core. Here we use the mMoSST numerical dynamo model to investigate the effects of a thin stably stratified layer at the top of the fluid outer core in Earth on the resulting large-scale geomagnetic field morphology. We find that the existence of a stable layer has significant influence on the octupolar component of the magnetic field in our models, whereas the quadrupole doesn't show an obvious trend. This suggests that observations of the geomagnetic field can be applied to provide information of the properties of this plausible stable layer, such as how thick and how stable this layer could be. Furthermore, we have examined whether the dominant thermal signature from mantle tomography at the core-mantle boundary (CMB) (a degree & order 2 spherical harmonic) can influence our results. We found that this heat flux pattern at the CMB has no outstanding effects on the quadrupole and octupole magnetic field components. Our studies suggest that if there is a stably stratified layer at the top of the Earth's core, it must be limited in terms of stability and thickness, in order to be compatible with the observed paleomagnetic record.

Experimental and numerical study on the onset of natural convection in a cavity open at the top

NASA Astrophysics Data System (ADS)

Saxena, Ashish; Kishor, Vimal; Singh, Suneet; Srivastava, Atul

2018-05-01

The onset of natural convection in a 2D air filled cavity open at the top with adiabatic side walls is studied. The numerical model shows the existence of weak convective flow near the top corner of a cavity due to the thermal gradient between the walls and the atmosphere even at low Rayleigh numbers, as also confirmed by the interferometry-based experimental data. Additionally, a thermally stratified layer is formed on the lower side of the cavity. The onset of convection is seen to be dependent on the interaction of these two features in the cavity. Results of the study show that in low aspect ratio cavities, the thermally stratified layers are clearly formed and are not significantly disturbed by the flow at the corners. The onset of convection takes place in these earlier thermally stratified layers beyond a certain Rayleigh number. This convective movement is characterized by a sudden jump in the heat transfer coefficient at a critical Rayleigh number. However, for high aspect ratio cavities, the flow at the corners has significant influence on the stratified layers and results in a decrease in the value of critical Rayleigh number. Beyond a certain aspect ratio, these layers cannot be formed and hence there is no onset of convection. Simulations as well as the interferometric measurements show an inherent symmetry in the corner flows, which was seen to breakdown due to the flow-induced instabilities in the thermally stratified layers for Rayleigh numbers greater than the critical value.

Almost All Antipsychotics Result in Weight Gain: A Meta-Analysis

PubMed Central

Bak, Maarten; Fransen, Annemarie; Janssen, Jouke; van Os, Jim; Drukker, Marjan

2014-01-01

Introduction Antipsychotics (AP) induce weight gain. However, reviews and meta-analyses generally are restricted to second generation antipsychotics (SGA) and do not stratify for duration of AP use. It is hypothesised that patients gain more weight if duration of AP use is longer. Method A meta-analysis was conducted of clinical trials of AP that reported weight change. Outcome measures were body weight change, change in BMI and clinically relevant weight change (7% weight gain or loss). Duration of AP-use was stratified as follows: ≤6 weeks, 6–16 weeks, 16–38 weeks and >38 weeks. Forest plots stratified by AP as well as by duration of use were generated and results were summarised in figures. Results 307 articles met inclusion criteria. The majority were AP switch studies. Almost all AP showed a degree of weight gain after prolonged use, except for amisulpride, aripiprazole and ziprasidone, for which prolonged exposure resulted in negligible weight change. The level of weight gain per AP varied from discrete to severe. Contrary to expectations, switch of AP did not result in weight loss for amisulpride, aripiprazole or ziprasidone. In AP-naive patients, weight gain was much more pronounced for all AP. Conclusion Given prolonged exposure, virtually all AP are associated with weight gain. The rational of switching AP to achieve weight reduction may be overrated. In AP-naive patients, weight gain is more pronounced. PMID:24763306

Almost all antipsychotics result in weight gain: a meta-analysis.

PubMed

Bak, Maarten; Fransen, Annemarie; Janssen, Jouke; van Os, Jim; Drukker, Marjan

2014-01-01

Antipsychotics (AP) induce weight gain. However, reviews and meta-analyses generally are restricted to second generation antipsychotics (SGA) and do not stratify for duration of AP use. It is hypothesised that patients gain more weight if duration of AP use is longer. A meta-analysis was conducted of clinical trials of AP that reported weight change. Outcome measures were body weight change, change in BMI and clinically relevant weight change (7% weight gain or loss). Duration of AP-use was stratified as follows: ≤6 weeks, 6-16 weeks, 16-38 weeks and >38 weeks. Forest plots stratified by AP as well as by duration of use were generated and results were summarised in figures. 307 articles met inclusion criteria. The majority were AP switch studies. Almost all AP showed a degree of weight gain after prolonged use, except for amisulpride, aripiprazole and ziprasidone, for which prolonged exposure resulted in negligible weight change. The level of weight gain per AP varied from discrete to severe. Contrary to expectations, switch of AP did not result in weight loss for amisulpride, aripiprazole or ziprasidone. In AP-naive patients, weight gain was much more pronounced for all AP. Given prolonged exposure, virtually all AP are associated with weight gain. The rational of switching AP to achieve weight reduction may be overrated. In AP-naive patients, weight gain is more pronounced.

Molecular subtyping of bladder cancer using Kohonen self-organizing maps.

PubMed

Borkowska, Edyta M; Kruk, Andrzej; Jedrzejczyk, Adam; Rozniecki, Marek; Jablonowski, Zbigniew; Traczyk, Magdalena; Constantinou, Maria; Banaszkiewicz, Monika; Pietrusinski, Michal; Sosnowski, Marek; Hamdy, Freddie C; Peter, Stefan; Catto, James W F; Kaluzewski, Bogdan

2014-10-01

Kohonen self-organizing maps (SOMs) are unsupervised Artificial Neural Networks (ANNs) that are good for low-density data visualization. They easily deal with complex and nonlinear relationships between variables. We evaluated molecular events that characterize high- and low-grade BC pathways in the tumors from 104 patients. We compared the ability of statistical clustering with a SOM to stratify tumors according to the risk of progression to more advanced disease. In univariable analysis, tumor stage (log rank P = 0.006) and grade (P < 0.001), HPV DNA (P < 0.004), Chromosome 9 loss (P = 0.04) and the A148T polymorphism (rs 3731249) in CDKN2A (P = 0.02) were associated with progression. Multivariable analysis of these parameters identified that tumor grade (Cox regression, P = 0.001, OR.2.9 (95% CI 1.6-5.2)) and the presence of HPV DNA (P = 0.017, OR 3.8 (95% CI 1.3-11.4)) were the only independent predictors of progression. Unsupervised hierarchical clustering grouped the tumors into discreet branches but did not stratify according to progression free survival (log rank P = 0.39). These genetic variables were presented to SOM input neurons. SOMs are suitable for complex data integration, allow easy visualization of outcomes, and may stratify BC progression more robustly than hierarchical clustering. © 2014 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.

Long-term on-farm participatory maize breeding by stratified mass selection retains molecular diversity while improving agronomic performance.

PubMed

Alves, Mara Lisa; Belo, Maria; Carbas, Bruna; Brites, Cláudia; Paulo, Manuel; Mendes-Moreira, Pedro; Brites, Carla; Bronze, Maria do Rosário; Šatović, Zlatko; Vaz Patto, Maria Carlota

2018-02-01

Modern maize breeding programs gave rise to genetically uniform varieties that can affect maize's capacity to cope with increasing climate unpredictability. Maize populations, genetically more heterogeneous, can evolve and better adapt to a broader range of edaphic-climatic conditions. These populations usually suffer from low yields; it is therefore desirable to improve their agronomic performance while maintaining their valuable diversity levels. With this objective, a long-term participatory breeding/on-farm conservation program was established in Portugal. In this program, maize populations were subject to stratified mass selection. This work aimed to estimate the effect of on-farm stratified mass selection on the agronomic performance, quality, and molecular diversity of two historical maize populations. Multilocation field trials, comparing the initial populations with the derived selection cycles, showed that this selection methodology led to agronomic improvement for one of the populations. The molecular diversity analysis, using microsatellites, revealed that overall genetic diversity in both populations was maintained throughout selection. The comparison of quality parameters between the initial populations and the derived selection cycles was made using kernel from a common-garden experiment. This analysis showed that the majority of the quality traits evaluated progressed erratically over time. In conclusion, this breeding approach, through simple and low-cost methodologies, proved to be an alternative strategy for genetic resources' on-farm conservation.

Flow and transport within a coastal aquifer adjacent to a stratified water body

NASA Astrophysics Data System (ADS)

Oz, Imri; Yechieli, Yoseph; Eyal, Shalev; Gavrieli, Ittai; Gvirtzman, Haim

2016-04-01

The existence of a freshwater-saltwater interface and the circulation flow of saltwater beneath the interface is a well-known phenomenon found at coastal aquifers. This flow is a natural phenomenon that occurs due to density differences between fresh groundwater and the saltwater body. The goals of this research are to use analytical, numerical, and physical models in order to examine the configuration of the freshwater-saltwater interface and the density-driven flow patterns within a coastal aquifer adjacent to long-term stratified saltwater bodies (e.g. meromictic lake). Such hydrological systems are unique, as they consist of three different water types: the regional fresh groundwater, and low and high salinity brines forming the upper and lower water layers of the stratified water body, respectively. This research also aims to examine the influence of such stratification on hydrogeological processes within the coastal aquifer. The coastal aquifer adjacent to the Dead Sea, under its possible future meromictic conditions, serves as an ideal example to examine these processes. The results show that adjacent to a stratified saltwater body three interfaces between three different water bodies are formed, and that a complex flow system, controlled by the density differences, is created, where three circulation cells are developed. These results are significantly different from the classic circulation cell that is found adjacent to non-stratified water bodies (lakes or oceans). In order to obtain a more generalized insight into the groundwater behavior adjacent to a stratified water body, we used the numerical model to perform sensitivity analysis. The hydrological system was found be sensitive to three dimensionless parameters: dimensionless density (i.e. the relative density of the three water bodies'); dimensionless thickness (i.e. the ratio between the relative thickness of the upper layer and the whole thickness of the lake); and dimensionless flux. The results also show that this configuration of three interfaces and three circulation cells, which is expected to develop adjacent to the stratified Dead Sea, is expected to decrease the dissolution rates of salt layer that is located within the adjacent aquifer, by one order of magnitude in comparison to the dissolution rates today. Therefore, the processes of salt dissolution and sinkhole formation adjacent to the Dead Sea will be relatively restrained.

Variability of Currents in Great South Channel and Over Georges Bank: Observation and Modeling

DTIC Science & Technology

1992-06-01

Rizzoli motivated me to study the driv:,: mechanism of stratified tidal rectification using diagnostic analysis methods . Conversations with Glen...drifter trajectories in the 1988 and 1989 surveys give further encouragement that the analysis method yields an accurate picture of the nontidal flow...harmonic truncation method . Scaling analysis argues that this method is not appropriate for a step topography because it is valid only when the

Performance and efficiency evaluation and heat release study of a direct-injection stratified-charge rotary engine

NASA Technical Reports Server (NTRS)

Nguyen, H. L.; Addy, H. E.; Bond, T. H.; Lee, C. M.; Chun, K. S.

1987-01-01

A computer simulation which models engine performance of the Direct Injection Stratified Charge (DISC) rotary engines was used to study the effect of variations in engine design and operating parameters on engine performance and efficiency of an Outboard Marine Corporation (OMC) experimental rotary combustion engine. Engine pressure data were used in a heat release analysis to study the effects of heat transfer, leakage, and crevice flows. Predicted engine data were compared with experimental test data over a range of engine speeds and loads. An examination of methods to improve the performance of the rotary engine using advanced heat engine concepts such as faster combustion, reduced leakage, and turbocharging is also presented.

Effect of risk-stratified, protocol-based perioperative chemoprophylaxis on nosocomial infection rates in a series of 31 927 consecutive neurosurgical procedures (1994-2006).

PubMed

Sharma, Manish S; Vohra, Ashma; Thomas, Ponnamma; Kapil, Arti; Suri, Ashish; Chandra, P Sarat; Kale, Shashank S; Mahapatra, Ashok K; Sharma, Bhawani S

2009-06-01

Although the use of prophylactic antibiotics has been shown to significantly decrease the incidence of meningitis after neurosurgery, its effect on extra-neurosurgical-site infections has not been documented. The authors explore the effect of risk-stratified, protocol-based perioperative antibiotic prophylaxis on nosocomial infections in an audit of 31 927 consecutive routine and emergency neurosurgical procedures. Infection rates were objectively quantified by bacteriological positivity on culture of cerebrospinal fluid (CSF), blood, urine, wound swab, and tracheal aspirate samples derived from patients with clinicoradiological features of sepsis. Infections were recorded as pulmonary, wound, blood, CSF, and urinary. The total numbers of hospital-acquired infections and the number of patients infected were also recorded. A protocol of perioperative antibiotic prophylaxis of variable duration stratified by patient risk factors was introduced in 2000, which was chosen as the historical turning point. The chi test was used to compare infection rates. A P value of <0.05 was considered significant. A total of 31 927 procedures were performed during the study period 1994-2006; 5171 culture-proven hospital-acquired infections (16.2%) developed in 3686 patients (11.6%). The most common infections were pulmonary (4.4%), followed by bloodstream (3.5%), urinary (3.0%), CSF (2.9%), and wound (2.5%). The incidence of positive tracheal, CSF, blood, wound, and urine cultures decreased significantly after 2000. Chemoprophylaxis, however, altered the prevalent bacterial flora and may have led to the emergence of methicillin-resistant Staphylococcus aureus. A risk-stratified protocol of perioperative antibiotic prophylaxis may help to significantly decrease not only neurosurgical, but also extra-neurosurgical-site body fluid bacteriological culture positivity.

Stratified premedication strategy for the prevention of contrast media hypersensitivity in high-risk patients.

PubMed

Lee, Suh-Young; Yang, Min Suk; Choi, Young-Hoon; Park, Chang Min; Park, Heung-Woo; Cho, Sang Heon; Kang, Hye-Ryun

2017-03-01

Although the severity of hypersensitivity reactions to iodinated contrast media varies, it is well correlated with the severity of recurrent reactions; however, prophylaxis protocols are not severity-stratified. To assess the outcomes of tailored prophylaxis according to the severity of hypersensitivity reactions to iodinated contrast media. Our premedication protocols were stratified based on the severity of previous reactions: (1) 4 mg of chlorpheniramine for mild reactions, (2) adding 40 mg of methylprednisolone for moderate reactions, and (3) adding multiple doses of 40 mg of methylprednisolone for severe index reactions. Cases of reexposure in patients with a history of hypersensitivity reactions were routinely monitored and mandatorily recorded. Among a total of 850 patients who underwent enhanced computed tomography after severity-tailored prophylaxis, breakthrough reactions occurred in 17.1%, but most breakthrough reactions (89.0%) were mild and did not require medical treatment. Additional corticosteroid use did not reduce the breakthrough reaction rate in cases with a mild index reaction (16.8% vs 17.2%, P = .70). However, underpremedication with a single dose of corticosteroid revealed significantly higher rates of breakthrough reaction than did double doses of corticosteroid in cases with a severe index reaction (55.6% vs 17.4%, P = .02). Changing the iodinated contrast media resulted in an additional reduction of the breakthrough reaction rate overall (14.9% vs 32.1%, P = .001). In a total severity-based stratified prophylaxis regimens and changing iodinated contrast media can be considered in patients with a history of previous hypersensitivity reaction to iodinated contrast media to reduce the risk of breakthrough reactions. Copyright © 2016 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Stratifying Parkinson's Patients With STN-DBS Into High-Frequency or 60 Hz-Frequency Modulation Using a Computational Model.

PubMed

Khojandi, Anahita; Shylo, Oleg; Mannini, Lucia; Kopell, Brian H; Ramdhani, Ritesh A

2017-07-01

High frequency stimulation (HFS) of the subthalamic nucleus (STN) is a well-established therapy for Parkinson's disease (PD), particularly the cardinal motor symptoms and levodopa induced motor complications. Recent studies have suggested the possible role of 60 Hz stimulation in STN-deep brain stimulation (DBS) for patients with gait disorder. The objective of this study was to develop a computational model, which stratifies patients a priori based on symptomatology into different frequency settings (i.e., high frequency or 60 Hz). We retrospectively analyzed preoperative MDS-Unified Parkinson's Disease Rating Scale III scores (32 indicators) collected from 20 PD patients implanted with STN-DBS at Mount Sinai Medical Center on either 60 Hz stimulation (ten patients) or HFS (130-185 Hz) (ten patients) for an average of 12 months. Predictive models using the Random Forest classification algorithm were built to associate patient/disease characteristics at surgery to the stimulation frequency. These models were evaluated objectively using leave-one-out cross-validation approach. The computational models produced, stratified patients into 60 Hz or HFS (130-185 Hz) with 95% accuracy. The best models relied on two or three predictors out of the 32 analyzed for classification. Across all predictors, gait and rest tremor of the right hand were consistently the most important. Computational models were developed using preoperative clinical indicators in PD patients treated with STN-DBS. These models were able to accurately stratify PD patients into 60 Hz stimulation or HFS (130-185 Hz) groups a priori, offering a unique potential to enhance the utilization of this therapy based on clinical subtypes. © 2017 International Neuromodulation Society.

Distribution-Preserving Stratified Sampling for Learning Problems.

PubMed

Cervellera, Cristiano; Maccio, Danilo

2017-06-09

The need for extracting a small sample from a large amount of real data, possibly streaming, arises routinely in learning problems, e.g., for storage, to cope with computational limitations, obtain good training/test/validation sets, and select minibatches for stochastic gradient neural network training. Unless we have reasons to select the samples in an active way dictated by the specific task and/or model at hand, it is important that the distribution of the selected points is as similar as possible to the original data. This is obvious for unsupervised learning problems, where the goal is to gain insights on the distribution of the data, but it is also relevant for supervised problems, where the theory explains how the training set distribution influences the generalization error. In this paper, we analyze the technique of stratified sampling from the point of view of distances between probabilities. This allows us to introduce an algorithm, based on recursive binary partition of the input space, aimed at obtaining samples that are distributed as much as possible as the original data. A theoretical analysis is proposed, proving the (greedy) optimality of the procedure together with explicit error bounds. An adaptive version of the algorithm is also introduced to cope with streaming data. Simulation tests on various data sets and different learning tasks are also provided.

Analysis and test of insulated components for rotary engine

NASA Technical Reports Server (NTRS)

Badgley, Patrick R.; Doup, Douglas; Kamo, Roy

1989-01-01

The direct-injection stratified-charge (DISC) rotary engine, while attractive for aviation applications due to its light weight, multifuel capability, and potentially low fuel consumption, has until now required a bulky and heavy liquid-cooling system. NASA-Lewis has undertaken the development of a cooling system-obviating, thermodynamically superior adiabatic rotary engine employing state-of-the-art thermal barrier coatings to thermally insulate engine components. The thermal barrier coating material for the cast aluminum, stainless steel, and ductile cast iron components was plasma-sprayed zirconia. DISC engine tests indicate effective thermal barrier-based heat loss reduction, but call for superior coefficient-of-thermal-expansion matching of materials and better tribological properties in the coatings used.

Effect of interleukin-6 polymorphism on risk of preterm birth within population strata: a meta-analysis.

PubMed

Wu, Wilfred; Clark, Erin A S; Stoddard, Gregory J; Watkins, W Scott; Esplin, M Sean; Manuck, Tracy A; Xing, Jinchuan; Varner, Michael W; Jorde, Lynn B

2013-04-25

Because of the role of inflammation in preterm birth (PTB), polymorphisms in and near the interleukin-6 gene (IL6) have been association study targets. Several previous studies have assessed the association between PTB and a single nucleotide polymorphism (SNP), rs1800795, located in the IL6 gene promoter region. Their results have been inconsistent and SNP frequencies have varied strikingly among different populations. We therefore conducted a meta-analysis with subgroup analysis by population strata to: (1) reduce the confounding effect of population structure, (2) increase sample size and statistical power, and (3) elucidate the association between rs1800975 and PTB. We reviewed all published papers for PTB phenotype and SNP rs1800795 genotype. Maternal genotype and fetal genotype were analyzed separately and the analyses were stratified by population. The PTB phenotype was defined as gestational age (GA) < 37 weeks, but results from earlier GA were selected when available. All studies were compared by genotype (CC versus CG+GG), based on functional studies.For the maternal genotype analysis, 1,165 PTBs and 3,830 term controls were evaluated. Populations were stratified into women of European descent (for whom the most data were available) and women of heterogeneous origin or admixed populations. All ancestry was self-reported. Women of European descent had a summary odds ratio (OR) of 0.68, (95% confidence interval (CI) 0.51 - 0.91), indicating that the CC genotype is protective against PTB. The result for non-European women was not statistically significant (OR 1.01, 95% CI 0.59 - 1.75). For the fetal genotype analysis, four studies were included; there was no significant association with PTB (OR 0.98, 95% CI 0.72 - 1.33). Sensitivity analysis showed that preterm premature rupture of membrane (PPROM) may be a confounding factor contributing to phenotype heterogeneity. IL6 SNP rs1800795 genotype CC is protective against PTB in women of European descent. It is not significant in other heterogeneous or admixed populations, or in fetal genotype analysis.Population structure is an important confounding factor that should be controlled for in studies of PTB.

Data splitting for artificial neural networks using SOM-based stratified sampling.

PubMed

May, R J; Maier, H R; Dandy, G C

2010-03-01

Data splitting is an important consideration during artificial neural network (ANN) development where hold-out cross-validation is commonly employed to ensure generalization. Even for a moderate sample size, the sampling methodology used for data splitting can have a significant effect on the quality of the subsets used for training, testing and validating an ANN. Poor data splitting can result in inaccurate and highly variable model performance; however, the choice of sampling methodology is rarely given due consideration by ANN modellers. Increased confidence in the sampling is of paramount importance, since the hold-out sampling is generally performed only once during ANN development. This paper considers the variability in the quality of subsets that are obtained using different data splitting approaches. A novel approach to stratified sampling, based on Neyman sampling of the self-organizing map (SOM), is developed, with several guidelines identified for setting the SOM size and sample allocation in order to minimize the bias and variance in the datasets. Using an example ANN function approximation task, the SOM-based approach is evaluated in comparison to random sampling, DUPLEX, systematic stratified sampling, and trial-and-error sampling to minimize the statistical differences between data sets. Of these approaches, DUPLEX is found to provide benchmark performance with good model performance, with no variability. The results show that the SOM-based approach also reliably generates high-quality samples and can therefore be used with greater confidence than other approaches, especially in the case of non-uniform datasets, with the benefit of scalability to perform data splitting on large datasets. Copyright 2009 Elsevier Ltd. All rights reserved.

Effectiveness of Provider and Community Interventions to Improve Treatment of Uncomplicated Malaria in Nigeria: A Cluster Randomized Controlled Trial.

PubMed

Onwujekwe, Obinna; Mangham-Jefferies, Lindsay; Cundill, Bonnie; Alexander, Neal; Langham, Julia; Ibe, Ogochukwu; Uzochukwu, Benjamin; Wiseman, Virginia

2015-01-01

The World Health Organization recommends that malaria be confirmed by parasitological diagnosis before treatment using Artemisinin-based Combination Therapy (ACT). Despite this, many health workers in malaria endemic countries continue to diagnose malaria based on symptoms alone. This study evaluates interventions to help bridge this gap between guidelines and provider practice. A stratified cluster-randomized trial in 42 communities in Enugu state compared 3 scenarios: Rapid Diagnostic Tests (RDTs) with basic instruction (control); RDTs with provider training (provider arm); and RDTs with provider training plus a school-based community intervention (provider-school arm). The primary outcome was the proportion of patients treated according to guidelines, a composite indicator requiring patients to be tested for malaria and given treatment consistent with the test result. The primary outcome was evaluated among 4946 (93%) of the 5311 patients invited to participate. A total of 40 communities (12 in control, 14 per intervention arm) were included in the analysis. There was no evidence of differences between the three arms in terms of our composite indicator (p = 0.36): stratified risk difference was 14% (95% CI -8.3%, 35.8%; p = 0.26) in the provider arm and 1% (95% CI -21.1%, 22.9%; p = 0.19) in the provider-school arm, compared with control. The level of testing was low across all arms (34% in control; 48% provider arm; 37% provider-school arm; p = 0.47). Presumptive treatment of uncomplicated malaria remains an ingrained behaviour that is difficult to change. With or without extensive supporting interventions, levels of testing in this study remained critically low. Governments and researchers must continue to explore alternative ways of encouraging providers to deliver appropriate treatment and avoid the misuse of valuable medicines. ClinicalTrials.gov NCT01350752.

Comparison of sampling strategies for object-based classification of urban vegetation from Very High Resolution satellite images

NASA Astrophysics Data System (ADS)

Rougier, Simon; Puissant, Anne; Stumpf, André; Lachiche, Nicolas

2016-09-01

Vegetation monitoring is becoming a major issue in the urban environment due to the services they procure and necessitates an accurate and up to date mapping. Very High Resolution satellite images enable a detailed mapping of the urban tree and herbaceous vegetation. Several supervised classifications with statistical learning techniques have provided good results for the detection of urban vegetation but necessitate a large amount of training data. In this context, this study proposes to investigate the performances of different sampling strategies in order to reduce the number of examples needed. Two windows based active learning algorithms from state-of-art are compared to a classical stratified random sampling and a third combining active learning and stratified strategies is proposed. The efficiency of these strategies is evaluated on two medium size French cities, Strasbourg and Rennes, associated to different datasets. Results demonstrate that classical stratified random sampling can in some cases be just as effective as active learning methods and that it should be used more frequently to evaluate new active learning methods. Moreover, the active learning strategies proposed in this work enables to reduce the computational runtime by selecting multiple windows at each iteration without increasing the number of windows needed.

A new approach to modelling schistosomiasis transmission based on stratified worm burden.

PubMed

Gurarie, D; King, C H; Wang, X

2010-11-01

Multiple factors affect schistosomiasis transmission in distributed meta-population systems including age, behaviour, and environment. The traditional approach to modelling macroparasite transmission often exploits the 'mean worm burden' (MWB) formulation for human hosts. However, typical worm distribution in humans is overdispersed, and classic models either ignore this characteristic or make ad hoc assumptions about its pattern (e.g., by assuming a negative binomial distribution). Such oversimplifications can give wrong predictions for the impact of control interventions. We propose a new modelling approach to macro-parasite transmission by stratifying human populations according to worm burden, and replacing MWB dynamics with that of 'population strata'. We developed proper calibration procedures for such multi-component systems, based on typical epidemiological and demographic field data, and implemented them using Wolfram Mathematica. Model programming and calibration proved to be straightforward. Our calibrated system provided good agreement with the individual level field data from the Msambweni region of eastern Kenya. The Stratified Worm Burden (SWB) approach offers many advantages, in that it accounts naturally for overdispersion and accommodates other important factors and measures of human infection and demographics. Future work will apply this model and methodology to evaluate innovative control intervention strategies, including expanded drug treatment programmes proposed by the World Health Organization and its partners.

Spectral reflectance of surface soils: Relationships with some soil properties

NASA Technical Reports Server (NTRS)

Kiesewetter, C. H.

1983-01-01

Using a published atlas of reflectance curves and physicochemical properties of soils, a statistical analysis was carried out. Reflectance bands which correspond to five of the wavebands used by NASA's Thematic Mapper were examined for relationships to specific soil properties. The properties considered in this study include: Sand Content, Silt Content, Clay Content, Organic Matter Content, Cation Exchange Capacity, Iron Oxide Content and Moisture Content. Regression of these seven properties on the mean values of five TM bands produced results that indicate that the predictability of the properties can be increased by stratifying the data. The data was stratified by parent material, taxonomic order, temperature zone, moisture zone and climate (combined temperature and moisture). The best results were obtained when the sample was examined by climatic classes. The middle Infra-red bands, 5 and 7, as well as the visible bands, 2 and 3, are significant in the model. The near Infra-red band, band 4, is almost as useful and should be included in any studies. General linear modeling procedures examined relationships of the seven properties with certain wavebands in the stratified samples.

Analysis of host response to bacterial infection using error model based gene expression microarray experiments

PubMed Central

Stekel, Dov J.; Sarti, Donatella; Trevino, Victor; Zhang, Lihong; Salmon, Mike; Buckley, Chris D.; Stevens, Mark; Pallen, Mark J.; Penn, Charles; Falciani, Francesco

2005-01-01

A key step in the analysis of microarray data is the selection of genes that are differentially expressed. Ideally, such experiments should be properly replicated in order to infer both technical and biological variability, and the data should be subjected to rigorous hypothesis tests to identify the differentially expressed genes. However, in microarray experiments involving the analysis of very large numbers of biological samples, replication is not always practical. Therefore, there is a need for a method to select differentially expressed genes in a rational way from insufficiently replicated data. In this paper, we describe a simple method that uses bootstrapping to generate an error model from a replicated pilot study that can be used to identify differentially expressed genes in subsequent large-scale studies on the same platform, but in which there may be no replicated arrays. The method builds a stratified error model that includes array-to-array variability, feature-to-feature variability and the dependence of error on signal intensity. We apply this model to the characterization of the host response in a model of bacterial infection of human intestinal epithelial cells. We demonstrate the effectiveness of error model based microarray experiments and propose this as a general strategy for a microarray-based screening of large collections of biological samples. PMID:15800204

A SWOT Analysis of Male and Female Students' Performance in Chemistry: A Comparative Study

ERIC Educational Resources Information Center

Ezeudu, Florence O.; Chiaha, Gertrude-Theresa Uzoamaka; Anazor, Lynda Chioma; Eze, Justina Uzoamaka; Omeke, Faith Chinwe

2015-01-01

The purpose of this study was to do a SWOT analysis and compare performances of male and female students in chemistry. Four research questions and four null hypotheses guided the study. Two boys', two girls' and two coeducational schools involving 1319 males and 1831 females, were selected by a stratified, deliberate sampling technique. A…

Maternal Smoking and Autism Spectrum Disorder: A Meta-Analysis

ERIC Educational Resources Information Center

Rosen, Brittany N.; Lee, Brian K.; Lee, Nora L.; Yang, Yunwen; Burstyn, Igor

2015-01-01

We conducted a meta-analysis of 15 studies on maternal prenatal smoking and ASD risk in offspring. Using a random-effects model, we found no evidence of an association (summary OR 1.02, 95% CI 0.93-1.12). Stratifying by study design, birth year, type of healthcare system, and adjustment for socioeconomic status or psychiatric history did not alter…

Predictors of Eligibility for ESY. Final Report.

ERIC Educational Resources Information Center

Browder, Diane M.; And Others

Evaluation of eligibility for extended school year (ESY) services was made based on informaton contained in school files in a stratified sampling across Pennsylvania. Subjects had been classified as severely and profoundly mentally retarded and were divided into groups based on eligibility for programming in excess of 180 days or ineligibility for…

Lake Superior Phytoplankton Characterization from the 2006 Probability Based Survey

EPA Science Inventory

We conducted a late summer probability based survey of Lake Superior in 2006 which consisted of 52 sites stratified across 3 depth zones. As part of this effort, we collected composite phytoplankton samples from the epilimnion and the fluorescence maxima (Fmax) at 29 of the site...

Gender-stratified analysis of DLG5 R30Q in 4707 patients with Crohn disease and 4973 controls from 12 Caucasian cohorts.

PubMed

Browning, B L; Annese, V; Barclay, M L; Bingham, S A; Brand, S; Büning, C; Castro, M; Cucchiara, S; Dallapiccola, B; Drummond, H; Ferguson, L R; Ferraris, A; Fisher, S A; Gearry, R B; Glas, J; Henckaerts, L; Huebner, C; Knafelz, D; Lakatos, L; Lakatos, P L; Latiano, A; Liu, X; Mathew, C; Müller-Myhsok, B; Newman, W G; Nimmo, E R; Noble, C L; Palmieri, O; Parkes, M; Petermann, I; Rutgeerts, P; Satsangi, J; Shelling, A N; Siminovitch, K A; Török, H-P; Tremelling, M; Vermeire, S; Valvano, M R; Witt, H

2008-01-01

DLG5 p.R30Q has been reported to be associated with Crohn disease (CD), but this association has not been replicated in most studies. A recent analysis of gender-stratified data from two case-control studies and two population cohorts found an association of DLG5 30Q with increased risk of CD in men but not in women and found differences between 30Q population frequencies for males and females. Male-female differences in population allele frequencies and male-specific risk could explain the difficulty in replicating the association with CD. DLG5 R30Q genotype data were collected for patients with CD and controls from 11 studies that did not include gender-stratified allele counts in their published reports and tested for male-female frequency differences in controls and for case-control frequency differences in men and in women. The data showed no male-female allele frequency differences in controls. An exact conditional test gave marginal evidence that 30Q is associated with decreased risk of CD in women (p = 0.049, OR = 0.87, 95% CI 0.77 to 1.00). There was also a trend towards reduced 30Q frequencies in male patients with CD compared with male controls, but this was not significant at the 0.05 level (p = 0.058, OR = 0.87, 95% CI 0.74 to 1.01). When data from this study were combined with previously published, gender-stratified data, the 30Q allele was found to be associated with decreased risk of CD in women (p = 0.010, OR = 0.86, 95% CI 0.76 to 0.97), but not in men. DLG5 30Q is associated with a small reduction in risk of CD in women.

Sub-grouping patients with non-specific low back pain based on cluster analysis of discriminatory clinical items.

PubMed

Billis, Evdokia; McCarthy, Christopher J; Roberts, Chris; Gliatis, John; Papandreou, Maria; Gioftsos, George; Oldham, Jacqueline A

2013-02-01

To identify potential subgroups amongst patients with non-specific low back pain based on a consensus list of potentially discriminatory examination items. Exploratory study. A convenience sample of 106 patients with non-specific low back pain (43 males, 63 females, mean age 36 years, standard deviation 15.9 years) and 7 physiotherapists. Based on 3 focus groups and a two-round Delphi involving 23 health professionals and a random stratified sample of 150 physiotherapists, respectively, a comprehensive examination list comprising the most "discriminatory" items was compiled. Following reliability analysis, the most reliable clinical items were assessed with a sample of patients with non-specific low back pain. K-means cluster analysis was conducted for 2-, 3- and 4-cluster options to explore for meaningful homogenous subgroups. The most clinically meaningful cluster was a two-subgroup option, comprising a small group (n = 24) with more severe clinical presentation (i.e. more widespread pain, functional and sleeping problems, other symptoms, increased investigations undertaken, more severe clinical signs, etc.) and a larger less dysfunctional group (n = 80). A number of potentially discriminatory clinical items were identified by health professionals and sub-classified, based on a sample of patients with non-specific low back pain, into two subgroups. However, further work is needed to validate this classification process.

Flow-graph approach for optical analysis of planar structures.

PubMed

Minkov, D

1994-11-20

The flow-graph approach (FGA) is applied to optical analysis of isotropic stratified planar structures (ISPS's) at inclined light incidence. Conditions for the presence of coherent and noncoherent light interaction within ISPS's are determined. Examples of the use of FGA for calculation of the transmission and the reflection of two-layer ISPS's for different types of light interaction are given. The advantages of the use of FGA for optical analysis of ISPS's are discussed.

Automated Analysis of Zooplankton Size and Taxonomic Composition.

DTIC Science & Technology

1998-07-01

Gallager, and P. Alatalo. Seasonal evolution of plankton and particle distributions across Georges Bank as measured using the Video Plankton Recorder... pteropods , and larvaceans estimated from concurrent Video Plankton Recorder and MOCNESS tows in the stratified region of Georges Bank. Deep Sea Res

Structure and functions of keratin proteins in simple, stratified, keratinized and cornified epithelia

PubMed Central

Bragulla, Hermann H; Homberger, Dominique G

2009-01-01

Historically, the term ‘keratin’ stood for all of the proteins extracted from skin modifications, such as horns, claws and hooves. Subsequently, it was realized that this keratin is actually a mixture of keratins, keratin filament-associated proteins and other proteins, such as enzymes. Keratins were then defined as certain filament-forming proteins with specific physicochemical properties and extracted from the cornified layer of the epidermis, whereas those filament-forming proteins that were extracted from the living layers of the epidermis were grouped as ‘prekeratins’ or ‘cytokeratins’. Currently, the term ‘keratin’ covers all intermediate filament-forming proteins with specific physicochemical properties and produced in any vertebrate epithelia. Similarly, the nomenclature of epithelia as cornified, keratinized or non-keratinized is based historically on the notion that only the epidermis of skin modifications such as horns, claws and hooves is cornified, that the non-modified epidermis is a keratinized stratified epithelium, and that all other stratified and non-stratified epithelia are non-keratinized epithelia. At this point in time, the concepts of keratins and of keratinized or cornified epithelia need clarification and revision concerning the structure and function of keratin and keratin filaments in various epithelia of different species, as well as of keratin genes and their modifications, in view of recent research, such as the sequencing of keratin proteins and their genes, cell culture, transfection of epithelial cells, immunohistochemistry and immunoblotting. Recently, new functions of keratins and keratin filaments in cell signaling and intracellular vesicle transport have been discovered. It is currently understood that all stratified epithelia are keratinized and that some of these keratinized stratified epithelia cornify by forming a Stratum corneum. The processes of keratinization and cornification in skin modifications are different especially with respect to the keratins that are produced. Future research in keratins will provide a better understanding of the processes of keratinization and cornification of stratified epithelia, including those of skin modifications, of the adaptability of epithelia in general, of skin diseases, and of the changes in structure and function of epithelia in the course of evolution. This review focuses on keratins and keratin filaments in mammalian tissue but keratins in the tissues of some other vertebrates are also considered. PMID:19422428

An evaluation of flow-stratified sampling for estimating suspended sediment loads

Treesearch

Robert B. Thomas; Jack Lewis

1995-01-01

Abstract - Flow-stratified sampling is a new method for sampling water quality constituents such as suspended sediment to estimate loads. As with selection-at-list-time (SALT) and time-stratified sampling, flow-stratified sampling is a statistical method requiring random sampling, and yielding unbiased estimates of load and variance. It can be used to estimate event...

Impact of aging on host immune response and survival in melanoma: an analysis of 3 patient cohorts.

PubMed

Weiss, Sarah A; Han, Joseph; Darvishian, Farbod; Tchack, Jeremy; Han, Sung Won; Malecek, Karolina; Krogsgaard, Michelle; Osman, Iman; Zhong, Judy

2016-10-19

Age has been reported as an independent prognostic factor for melanoma-specific survival (MSS). We tested the hypothesis that age impacts the host anti-tumor immune response, accounting for age-specific survival outcomes in three unique melanoma patient cohorts. We queried the U.S. population-based Surveillance, Epidemiology, and End Results Program (SEER), the prospective tertiary care hospital-based Interdisciplinary Melanoma Cooperative Group (IMCG) biorepository, and the Cancer Genome Atlas (TCGA) biospecimen database to test the association of patient age at time of melanoma diagnosis with clinicopathologic features and survival outcomes. Age groups were defined as ≤45 (young), 46-65 (intermediate), and >65 (older). Each age group in the IMCG and TCGA cohorts was stratified by tumor infiltrating lymphocyte (TIL) measurements and tested for association with MSS. Differential expression of 594 immunoregulatory genes was assessed in a subset of primary melanomas in the IMCG and TCGA cohorts using an integrative pathway analysis. We analyzed 304, 476 (SEER), 1241 (IMCG), and 292 (TCGA) patients. Increasing age at melanoma diagnosis in both the SEER and IMCG cohorts demonstrated a positive correlation with tumor thickness, ulceration, stage, and mortality, however age in the TCGA cohort did not correlate with mortality. Older age was associated with shorter MSS in all three cohorts. When the young age group in both the IMCG and TCGA cohorts was stratified by TIL status, there were no differences in MSS. However, older IMCG patients with brisk TILs and intermediate aged TCGA patients with high lymphocyte scores (3-6) had improved MSS. Gene expression analysis revealed top pathways (T cell trafficking, communication, and differentiation) and top upstream regulators (CD3, CD28, IFNG, and STAT3) that significantly changed with age in 84 IMCG and 43 TCGA primary melanomas. Older age at time of melanoma diagnosis is associated with shorter MSS, however age's association with clinicopathologic features is dependent upon specific characteristics of the study population. TIL as a read-out of the host immune response may have greater prognostic impact in patients older than age 45. Recognition of age-related factors negatively impacting host immune responses may provide new insights into therapeutic strategies for the elderly.

Automated analysis of electronic medical record data reflects the pathophysiology of operative complications.

PubMed

Tepas, Joseph J; Rimar, Joan M; Hsiao, Allen L; Nussbaum, Michael S

2013-10-01

We hypothesized that a novel algorithm that uses data from the electronic medical record (EMR) from multiple clinical and biometric sources could provide early warning of organ dysfunction in patients with high risk for postoperative complications and sepsis. Operative patients undergoing colorectal procedures were evaluated. The Rothman Index (RI) is a predictive model based on heuristic equations derived from 26 variables related to inpatient care. The RI integrates clinical nursing observations, bedside biometrics, and laboratory data into a continuously updated, numeric physiologic assessment, ranging from 100 (unimpaired) to -91. The RI can be displayed within the EMR as a graphic trend, with a decreasing trend reflecting physiologic dysfunction. Patients undergoing colorectal procedures between June and October 2011 were evaluated to determine correlation of initial RI, average inpatient RI, and lowest RI to incidence of complications and/or postoperative sepsis. Patients were stratified by color-coded RI risk group (100-65, blue; 64-40, yellow; <40 red). One-way or repeated-measures analysis of variance was used to compare groups by age, number of complications, and presence of sepsis defined by discharge International Classification of Diseases, 9(th) Revision, codes. Mean direct cost of care and duration of stay also was calculated for each group. The overall incidence of perioperative complications in the 124 patient cohort was 51% (n = 64 patients). The 261 complications sustained by this group represented 82 distinct diagnoses. The 10 patients with sepsis (8%) experienced a 40% mortality. Analysis of initial RI for the population stratified by number of complications and/or sepsis demonstrated a risk-related difference. With progressive onset of complications, the RI decreased, suggesting worsening physiologic dysfunction and linear increase in direct cost of care. These findings demonstrate that EMR data can be automatically compiled into an objective metric that reflects patient risk and changing physiologic state. The automated process of continuous update reflects a physiologic trajectory associated with evolving organ system dysfunction indicative of postoperative complications. Early intervention based on these trends may guide preoperative counseling, enhance pre-emptive management of adverse occurrences, and improve cost-efficiency of care. Copyright © 2013 Mosby, Inc. All rights reserved.

Air pollution and the incidence of ischaemic and haemorrhagic stroke in the South London Stroke Register: a case-cross-over analysis.

PubMed

Butland, B K; Atkinson, R W; Crichton, S; Barratt, B; Beevers, S; Spiridou, A; Hoang, U; Kelly, F J; Wolfe, C D

2017-07-01

Few European studies investigating associations between short-term exposure to air pollution and incident stroke have considered stroke subtypes. Using information from the South London Stroke Register for 2005-2012, we investigated associations between daily concentrations of gaseous and particulate air pollutants and incident stroke subtypes in an ethnically diverse area of London, UK. Modelled daily pollutant concentrations based on a combination of measurements and dispersion modelling were linked at postcode level to incident stroke events stratified by haemorrhagic and ischaemic subtypes. The data were analysed using a time-stratified case-cross-over approach. Conditional logistic regression models included natural cubic splines for daily mean temperature and daily mean relative humidity, a binary term for public holidays and a sine-cosine annual cycle. Of primary interest were same day mean concentrations of particulate matter <2.5 and <10 µm in diameter (PM 2.5 , PM 10 ), ozone (O 3 ), nitrogen dioxide (NO 2 ) and NO 2 +nitrogen oxide (NO X ). Our analysis was based on 1758 incident strokes (1311 were ischaemic and 256 were haemorrhagic). We found no evidence of an association between all stroke or ischaemic stroke and same day exposure to PM 2.5 , PM 10 , O 3 , NO 2 or NO X . For haemorrhagic stroke, we found a negative association with PM 10 suggestive of a 14.6% (95% CI 0.7% to 26.5%) fall in risk per 10 µg/m 3 increase in pollutant. Using data from the South London Stroke Register, we found no evidence of a positive association between outdoor air pollution and incident stroke or its subtypes. These results, though in contrast to recent meta-analyses, are not inconsistent with the mixed findings of other UK studies. 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/.

Molecular Diagnostic Yield of Chromosomal Microarray Analysis and Whole-Exome Sequencing in Children With Autism Spectrum Disorder.

PubMed

Tammimies, Kristiina; Marshall, Christian R; Walker, Susan; Kaur, Gaganjot; Thiruvahindrapuram, Bhooma; Lionel, Anath C; Yuen, Ryan K C; Uddin, Mohammed; Roberts, Wendy; Weksberg, Rosanna; Woodbury-Smith, Marc; Zwaigenbaum, Lonnie; Anagnostou, Evdokia; Wang, Zhuozhi; Wei, John; Howe, Jennifer L; Gazzellone, Matthew J; Lau, Lynette; Sung, Wilson W L; Whitten, Kathy; Vardy, Cathy; Crosbie, Victoria; Tsang, Brian; D'Abate, Lia; Tong, Winnie W L; Luscombe, Sandra; Doyle, Tyna; Carter, Melissa T; Szatmari, Peter; Stuckless, Susan; Merico, Daniele; Stavropoulos, Dimitri J; Scherer, Stephen W; Fernandez, Bridget A

2015-09-01

The use of genome-wide tests to provide molecular diagnosis for individuals with autism spectrum disorder (ASD) requires more study. To perform chromosomal microarray analysis (CMA) and whole-exome sequencing (WES) in a heterogeneous group of children with ASD to determine the molecular diagnostic yield of these tests in a sample typical of a developmental pediatric clinic. The sample consisted of 258 consecutively ascertained unrelated children with ASD who underwent detailed assessments to define morphology scores based on the presence of major congenital abnormalities and minor physical anomalies. The children were recruited between 2008 and 2013 in Newfoundland and Labrador, Canada. The probands were stratified into 3 groups of increasing morphological severity: essential, equivocal, and complex (scores of 0-3, 4-5, and ≥6). All probands underwent CMA, with WES performed for 95 proband-parent trios. The overall molecular diagnostic yield for CMA and WES in a population-based ASD sample stratified in 3 phenotypic groups. Of 258 probands, 24 (9.3%, 95%CI, 6.1%-13.5%) received a molecular diagnosis from CMA and 8 of 95 (8.4%, 95%CI, 3.7%-15.9%) from WES. The yields were statistically different between the morphological groups. Among the children who underwent both CMA and WES testing, the estimated proportion with an identifiable genetic etiology was 15.8% (95%CI, 9.1%-24.7%; 15/95 children). This included 2 children who received molecular diagnoses from both tests. The combined yield was significantly higher in the complex group when compared with the essential group (pairwise comparison, P = .002). [table: see text]. Among a heterogeneous sample of children with ASD, the molecular diagnostic yields of CMA and WES were comparable, and the combined molecular diagnostic yield was higher in children with more complex morphological phenotypes in comparison with the children in the essential category. If replicated in additional populations, these findings may inform appropriate selection of molecular diagnostic testing for children affected by ASD.

Percutaneous intervention versus coronary artery bypass graft surgery in left main coronary artery stenosis: a systematic review and meta-analysis.

PubMed

Zhang, Xin-Lin; Zhu, Qing-Qing; Yang, Jing-Jing; Chen, Yu-Han; Li, Yang; Zhu, Su-Hui; Xie, Jun; Wang, Lian; Kang, Li-Na; Xu, Biao

2017-04-21

The optimal revascularization technique in patients with left main coronary artery disease (CAD) remains controversial. We aimed to compare the long-term performance of percutaneous coronary intervention (PCI) versus coronary artery bypass graft (CABG) surgery in treatment of left main CAD. PubMed, EMBASE, and the Cochrane Library were searched until November 16, 2016. Six randomized controlled trials and 22 matched observational studies including 22,487 patients and 90,167 patient-years of follow-up were included. PCI was associated with an overall higher risk for the major adverse cardiac and cerebrovascular events (hazard ratio (HR), 1.42; 95% confidence interval (CI), 1.14-1.77), mainly driven by higher rates of myocardial infarction (HR, 1.69; 95% CI, 1.22-2.34) and revascularization (HR, 2.80; 95% CI, 1.86-4.22). The overall risks for all-cause death (HR, 1.05; 95% CI, 0.93-1.20), cardiac death (HR, 1.05; 95% CI, 0.69-1.59), stroke (HR, 0.64; 95% CI, 0.33-1.24), and the composite safety endpoint of death, myocardial infarction, or stroke (HR, 1.06; 95% CI, 0.97-1.16) were similar between PCI and CABG. Stratified analysis based on stent types showed that the increased risk for myocardial infarction associated with PCI was only evident in patients with bare-metal stents or early-generation drug-eluting stents (DES), but not newer-generation DES. Stratified analyses based on study designs showed largely similar findings with the overall analyses, except for a significantly higher incidence of myocardial infarction in adjusted studies (HR, 2.01; 95% CI, 1.64-2.45) but a trend toward higher incidence in randomized trials (HR, 1.39; 95% CI, 0.85-2.27) associated with PCI. Compared with CABG, PCI with newer-generation DES might be a safe alternative revascularization strategy for treatment of left main CAD, but is associated with more repeat revascularization.

Neurodevelopmental outcomes of infants with very low birth weights are associated with the severity of their extra-uterine growth retardation.

PubMed

Chien, Han-Chun; Chen, Chao-Huei; Wang, Teh-Ming; Hsu, Ya-Chi; Lin, Ming-Chih

2018-04-01

For infants with very low birth weights (VLBW), their neurodevelopmental outcomes are thought to be associated with extra-uterine growth retardation (EUGR). In this study, based on a single institute, we analyzed the association between different levels or severity of EUGR of VLBW infants and their neurodevelopmental outcomes later at a corrected age of 24 months. This is a hospital-based retrospective cohort study. The severity of EUGR was classified into three categories according to the z-score of discharge weight: z < -2.0, <-2.5, and <-3.0. The outcomes were assessed using the Bayley Scales of Infant Development-II (BSID-II) at a corrected age of 24 months. We then estimated the association of EUGR with low mental developmental index (MDI) or low psychomotor developmental index (PDI). Multiple logistic regression and stratified analyses were used to adjust for the possible confounding factors. In total, 224 VLBW infants were enrolled in this study from 1997 to 2006. In the univariate analysis, EUGR for weight at discharge from hospital was associated with MDI <85 at the corrected age of 24 months, and this association was related to the severity of EUGR (z < -2.5, OR: 1.92 (1.04-3.53); z < -3.0, OR: 2.83 (1.26-6.36)). In addition, the relationship was not confounded by gender nor small for gestational age. The stratified analysis against hemodynamic significant patent ductus arteriosus also revealed that EUGR was an independent predictor for neurodevelopmental outcomes. In VLBW preterm infants, EUGR was significantly associated with low MDI scores assessed at a corrected age of 24 months. Early evaluation and recognition of EUGR should be emphasized when caring for preterm infants. Copyright © 2017. Published by Elsevier B.V.

Cost-effectiveness of the implantable cardioverter defibrillator: a review of current evidence.

PubMed

Lynd, Larry D; O'Brien, Bernie J

2003-09-01

Implantable cardioverter defibrillator (ICD) therapy is indicated for patients at risk for sudden cardiac death (SCD) due to ventricular tachycardia (VT) or ventricular fibrillation (VF). The high relative cost of therapy with the ICD versus antiarrhythmic drugs has raised questions regarding its cost-effectiveness. To address these questions, we review the literature on ICD cost-effectiveness. MEDLINE and other databases were searched for articles published since 1980 reporting original data on the cost-effectiveness of ICD versus drug therapy for patients at risk for SCD. Data on costs and life-years were abstracted and studies grouped into decision analysis models and trial-based analyses. Cost-effectiveness ratios were inflated to 2002 US dollars. Thirteen economic studies were included in this review: 6 decision-analytic models, 4 economic analysis alongside randomized controlled trials, and 1 observational study. Two additional studies evaluated the cost-effectiveness of ICDs stratified by mortality risk. Studies varied in time horizon, and in all but one study ICD therapy was more costly than drug therapy. Early models assumed larger survival benefits than were observed in subsequent trials; therefore, ICDs appeared to be more cost-effective (i.e., US dollars 28000-US dollars 60000 per life-year gained). Three large clinical trial-based studies estimated that the cost per life-year gained was between US dollars 30181 and US dollars 185000. Stratified analyses show that patients at higher risk for mortality due to structural heart disease (e.g., left ventricular ejection fraction <35%) benefit more from ICD therapy, resulting in lower cost-effectiveness ratios. ICD therapy continues to evolve with changing methods of implantation and improving technology. Current evidence suggests that ICDs may be a cost-effective option in patients at high risk for VT/VF. The cost-effectiveness of ICD therapy for primary and secondary prevention of SCD depends upon patient characteristics that influence their prior risk of mortality. Further research on patient selection criteria and the measurement of health-related quality of life is required.

Meta-analytic approaches to determine gender differences in the age-incidence characteristics of schizophrenia and related psychoses.

PubMed

Jackson, Dan; Kirkbride, James; Croudace, Tim; Morgan, Craig; Boydell, Jane; Errazuriz, Antonia; Murray, Robin M; Jones, Peter B

2013-03-01

A recent systematic review and meta-analysis of the incidence and prevalence of schizophrenia and other psychoses in England investigated the variation in the rates of psychotic disorders. However, some of the questions of interest, and the data collected to answer these, could not be adequately addressed using established meta-analysis techniques. We developed a novel statistical method, which makes combined use of fractional polynomials and meta-regression. This was used to quantify the evidence of gender differences and a secondary peak onset in women, where the outcome of interest is the incidence of schizophrenia. Statistically significant and epidemiologically important effects were obtained using our methods. Our analysis is based on data from four studies that provide 50 incidence rates, stratified by age and gender. We describe several variations of our method, in particular those that might be used where more data is available, and provide guidance for assessing the model fit. Copyright © 2013 John Wiley & Sons, Ltd.

[Path analysis on workplace violence affecting work ability, job satisfaction and turnover intent in health professionals in Shangqiu City].

PubMed

Wang, Pei-xi; Wang, Mian-zhen; Bai, Qin; Jia, Cai-feng; Lan, Ya-jia; Wang, Zhi-ming; Luan, Rong-sheng

2006-11-01

To explore the effects of workplace violence on work ability, work satisfaction and turnover intent based on the theory of occupational stress in health professionals and to provide evidence for evaluating the process and consequence of workplace violence. Subjects of 483 health professionals from 5 hospitals in Shangqiu city of Hennan Province were selected with stratified cluster random sampling method. Workplace violence, violent fear at work, coping resources, work ability, job satisfaction and turnover intent were measured with questionnaires. Ordinal regression analysis and path analysis were applied to analyze the data. Workplace violence had direct or indirect effects on the work ability and job satisfaction through the fear of future violence at work. Workplace violence only had indirect effects on turnover intent through the fear and job satisfaction in health professionals. Workplace violence had direct and indirect effects on the work ability, job satisfaction and turnover intent. Measures should be taken to reduce workplace violence and it' s effects in health professionals.

[Item function analysis on the Quality of Life-Alzheimer's Disease(QOL-AD)Chinese version, based on the Item Response Theory(IRT)].

PubMed

Wan, Li-ping; He, Run-lian; Ai, Yong-mei; Zhang, Hui-min; Xing, Min; Yang, Lin; Song, Yan-long; Yu, Hong-mei

2013-07-01

To introduce the Item Function Analysis(IFA) of Quality of Life- Alzheimer's disease(QOL-AD)Chinese version and to explore the feasibility of its application on Chinese patients with AD. Two hundred AD patients were interviewed and assessed by QOL-AD, through the stratified cluster sampling method. Multilog 7.03. was used for Item Function Analysis. Difference scale(a), difficulty scale(b)and Item Characteristic Curve(ICC) of each item of QOL-AD were provided. Different scales of the item 1, 7 were below 0.6, while all the others were above 0.6. As for ICC. The first and last lines for the other items were monotonic in which the two in between were in inverted V-shape, with very steep slopes, except for the item 1 and 7. Results form the IFA showed that QOL-AD was applicable to be used in the Chinese patients with AD.

Visual accumulation tube for size analysis of sands

USGS Publications Warehouse

Colby, B.C.; Christensen, R.P.

1956-01-01

The visual-accumulation-tube method was developed primarily for making size analyses of the sand fractions of suspended-sediment and bed-material samples. Because the fundamental property governing the motion of a sediment particle in a fluid is believed to be its fall velocity. the analysis is designed to determine the fall-velocity-frequency distribution of the individual particles of the sample. The analysis is based on a stratified sedimentation system in which the sample is introduced at the top of a transparent settling tube containing distilled water. The procedure involves the direct visual tracing of the height of sediment accumulation in a contracted section at the bottom of the tube. A pen records the height on a moving chart. The method is simple and fast, provides a continuous and permanent record, gives highly reproducible results, and accurately determines the fall-velocity characteristics of the sample. The apparatus, procedure, results, and accuracy of the visual-accumulation-tube method for determining the sedimentation-size distribution of sands are presented in this paper.

Folic acid supplements and colorectal cancer risk: meta-analysis of randomized controlled trials

NASA Astrophysics Data System (ADS)

Qin, Tingting; Du, Mulong; Du, Haina; Shu, Yongqian; Wang, Meilin; Zhu, Lingjun

2015-07-01

Numerous studies have investigated the effects of folic acid supplementation on colorectal cancer risk, but conflicting results were reported. We herein performed a meta-analysis based on relevant studies to reach a more definitive conclusion. The PubMed and Embase databases were searched for quality randomized controlled trials (RCTs) published before October 2014. Eight articles met the inclusion criteria and were subsequently analyzed. The results suggested that folic acid treatment was not associated with colorectal cancer risk in the total population (relative risk [RR] = 1.00, 95% confidence interval [CI] = 0.82-1.22, P = 0.974). Moreover, no statistical effect was identified in further subgroup analyses stratified by ethnicity, gender, body mass index (BMI) and potential confounding factors. No significant heterogeneity or publication bias was observed. In conclusion, our meta-analysis demonstrated that folic acid supplementation had no effect on colorectal cancer risk. However, this finding must be validated by further large studies.

Definition of two-phase flow behaviors for spacecraft design

NASA Technical Reports Server (NTRS)

Reinarts, Thomas R.; Best, Frederick R.; Miller, Katherine M.; Hill, Wayne S.

1991-01-01

Data for complete models of two-phase flow in microgravity are taken from in-flight experiments and applied to an adiabatic flow-regime analysis to study the feasibility of two-phase systems for spacecraft. The data are taken from five in-flight experiments by Hill et al. (1990) in which a two-phase pump circulates a freon mixture and vapor and liquid flow streams are measured. Adiabatic flow regimes are analyzed based on the experimental superficial velocities of liquid and vapor, and comparisons are made with the results of two-phase flow regimes at 1 g. A motion analyzer records the flow characteristics at a rate of 1000 frames/sec, and stratified flow regimes are reported at 1 g. The flow regimes observed under microgravitational conditions are primarily annular and include slug and bubbly-slug regimes. The present data are of interest to the design and analysis of two-phase thermal-management systems for use in space missions.

MTHFR genetic polymorphisms may contribute to the risk of chronic myelogenous leukemia in adults: a meta-analysis of 12 genetic association studies.

PubMed

Li, Bin; Zhang, Jian; Wang, Lei; Li, Yan; Jin, Juping; Ai, Limei; Li, Chong; Li, Zhe; Mao, Shudan

2014-05-01

Chronic myelogenous leukemia (CML) is a complex disease with a genetic basis. The genetic association studies (GASs) that have investigated the association between adult CML and 5,10-methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C polymorphisms have produced contradictory and inconclusive results. The aim of this meta-analysis is to provide a relatively comprehensive assessment of the association of these polymorphisms with adult CML risk. A literature search for eligible GAS published before September 15, 2013 was conducted in PubMed, Embase, Web of Science, Cochrane Library, and China National Knowledge Infrastructure (CNKI) databases. Pooled odds ratios (ORs) with their corresponding 95% confidence intervals (95% CIs) were used to evaluate the strength of the association under a fixed or random effect model according to heterogeneity test results. All analyses were performed using the Stata software, version 12.0. Twelve case-control studies were included in this meta-analysis with a total of 932 CML patients and 3,465 healthy controls. For MTHFR C677T (dbSNP: rs1801133, C>T), though the pooled ORs were not significant in the overall population, all the ORs greater than 1 suggested an increased risk of CML for carriers of the risk allele. However, stratified analysis based on genotyping method revealed a significant association in the PCR-restriction fragment length polymorphism (RFLP) subgroup, possibly as a result of heterogeneity. For MTHFR A1298C (dbSNP: rs1801131, A>C), the combined results showed that carriers of the C allele may be associated with a decreased risk of adult CML. Stratified analysis showed that the magnitude of this effect was especially significant among Asians, indicating ethnicity differences in adult CML susceptibility. This meta-analysis shows that the C allele of MTHFR A1298C may be associated with a decreased risk in adult CML, especially among Asians, while MTHFR C677T may not be associated with adult CML risk. However, the development of adult CML may be the result of gene-gene and gene-environment interactions, which should be considered in future individual GAS and subsequent meta-analyses.

Development and assessment of an e-learning course on breast imaging for radiographers: a stratified randomized controlled trial.

PubMed

Moreira, Inês C; Ventura, Sandra Rua; Ramos, Isabel; Rodrigues, Pedro Pereira

2015-01-05

Mammography is considered the best imaging technique for breast cancer screening, and the radiographer plays an important role in its performance. Therefore, continuing education is critical to improving the performance of these professionals and thus providing better health care services. Our goal was to develop an e-learning course on breast imaging for radiographers, assessing its efficacy, effectiveness, and user satisfaction. A stratified randomized controlled trial was performed with radiographers and radiology students who already had mammography training, using pre- and post-knowledge tests, and satisfaction questionnaires. The primary outcome was the improvement in test results (percentage of correct answers), using intention-to-treat and per-protocol analysis. A total of 54 participants were assigned to the intervention (20 students plus 34 radiographers) with 53 controls (19+34). The intervention was completed by 40 participants (11+29), with 4 (2+2) discontinued interventions, and 10 (7+3) lost to follow-up. Differences in the primary outcome were found between intervention and control: 21 versus 4 percentage points (pp), P<.001. Stratified analysis showed effect in radiographers (23 pp vs 4 pp; P=.004) but was unclear in students (18 pp vs 5 pp; P=.098). Nonetheless, differences in students' posttest results were found (88% vs 63%; P=.003), which were absent in pretest (63% vs 63%; P=.106). The per-protocol analysis showed a higher effect (26 pp vs 2 pp; P<.001), both in students (25 pp vs 3 pp; P=.004) and radiographers (27 pp vs 2 pp; P<.001). Overall, 85% were satisfied with the course, and 88% considered it successful. This e-learning course is effective, especially for radiographers, which highlights the need for continuing education.

Development and Assessment of an E-Learning Course on Breast Imaging for Radiographers: A Stratified Randomized Controlled Trial

PubMed Central

Ventura, Sandra Rua; Ramos, Isabel; Rodrigues, Pedro Pereira

2015-01-01

Background Mammography is considered the best imaging technique for breast cancer screening, and the radiographer plays an important role in its performance. Therefore, continuing education is critical to improving the performance of these professionals and thus providing better health care services. Objective Our goal was to develop an e-learning course on breast imaging for radiographers, assessing its efficacy, effectiveness, and user satisfaction. Methods A stratified randomized controlled trial was performed with radiographers and radiology students who already had mammography training, using pre- and post-knowledge tests, and satisfaction questionnaires. The primary outcome was the improvement in test results (percentage of correct answers), using intention-to-treat and per-protocol analysis. Results A total of 54 participants were assigned to the intervention (20 students plus 34 radiographers) with 53 controls (19+34). The intervention was completed by 40 participants (11+29), with 4 (2+2) discontinued interventions, and 10 (7+3) lost to follow-up. Differences in the primary outcome were found between intervention and control: 21 versus 4 percentage points (pp), P<.001. Stratified analysis showed effect in radiographers (23 pp vs 4 pp; P=.004) but was unclear in students (18 pp vs 5 pp; P=.098). Nonetheless, differences in students’ posttest results were found (88% vs 63%; P=.003), which were absent in pretest (63% vs 63%; P=.106). The per-protocol analysis showed a higher effect (26 pp vs 2 pp; P<.001), both in students (25 pp vs 3 pp; P=.004) and radiographers (27 pp vs 2 pp; P<.001). Overall, 85% were satisfied with the course, and 88% considered it successful. Conclusions This e-learning course is effective, especially for radiographers, which highlights the need for continuing education. PMID:25560547

Comparison between thromboelastography and conventional coagulation test: Should we abandon conventional coagulation tests in polytrauma patients?

PubMed

Tur Martínez, Jaume; Petrone, Patrizio; Axelrad, Alexander; Marini, Corrado P

2018-05-12

TEG provides an in-vivo assessment of viscoelastic clot strength in whole blood compared with CCT, which may not reflect the influence of platelets. The aim of this study was to compare TEG vs. CCT in trauma patients stratified by mechanism of injury (MOI) and pre-existing coagulation status. A retrospective, observational study of 230 polytrauma patients admitted to a University Hospital Level 1 Trauma Center, with TEG and CCT on admission stratified by MOI: multiple trauma (MT), isolated traumatic brain injury (TBI) or MT+TBI. Statistical analysis included correlation between TEG and CCT in all groups and a subgroup analysis of anticoagulated patients. Data were analyzed with ANOVA, Spearman and lineal regression when appropriate. Statistical significance was accepted at P<0.05. TEG was normal in 28.7%, hypercoagulable in 68.3%, hypocoagulable in 7%. There was no difference in TEG status among the groups. The coagulation status was not affected by age, ISS or shock. The CCT were abnormal in 63.6% of patients with normal TEG. Normal or hypercoagulable-TEG was found in 21/23 patients on Coumadin who had elevated INR and in 10/11 patients on NOAC. An analysis of the 23 patients on Coumadin stratified by INR showed a normal or hypercoagulable-TEG in 21/23 patients. Only 2 patients had a hypocoagulable-TEG. Mortality was 5.2% (58.3% severe TBI). TEG is more useful than CCT in polytrauma patients, including patients on anticoagulants. TBI could increase the incidence of hypercoagulability in trauma. CCT are not useful from the standpoint of treatment. Copyright © 2018 AEC. Publicado por Elsevier España, S.L.U. All rights reserved.

Iodine and mental development of children 5 years old and under: a systematic review and meta-analysis.

PubMed

Bougma, Karim; Aboud, Frances E; Harding, Kimberly B; Marquis, Grace S

2013-04-22

Several reviews and meta-analyses have examined the effects of iodine on mental development. None focused on young children, so they were incomplete in summarizing the effects on this important age group. The current systematic review therefore examined the relationship between iodine and mental development of children 5 years old and under. A systematic review of articles using Medline (1980-November 2011) was carried out. We organized studies according to four designs: (1) randomized controlled trial with iodine supplementation of mothers; (2) non-randomized trial with iodine supplementation of mothers and/or infants; (3) prospective cohort study stratified by pregnant women's iodine status; (4) prospective cohort study stratified by newborn iodine status. Average effect sizes for these four designs were 0.68 (2 RCT studies), 0.46 (8 non-RCT studies), 0.52 (9 cohort stratified by mothers' iodine status), and 0.54 (4 cohort stratified by infants' iodine status). This translates into 6.9 to 10.2 IQ points lower in iodine deficient children compared with iodine replete children. Thus, regardless of study design, iodine deficiency had a substantial impact on mental development. Methodological concerns included weak study designs, the omission of important confounders, small sample sizes, the lack of cluster analyses, and the lack of separate analyses of verbal and non-verbal subtests. Quantifying more precisely the contribution of iodine deficiency to delayed mental development in young children requires more well-designed randomized controlled trials, including ones on the role of iodized salt.

Training set optimization under population structure in genomic selection.

PubMed

Isidro, Julio; Jannink, Jean-Luc; Akdemir, Deniz; Poland, Jesse; Heslot, Nicolas; Sorrells, Mark E

2015-01-01

Population structure must be evaluated before optimization of the training set population. Maximizing the phenotypic variance captured by the training set is important for optimal performance. The optimization of the training set (TRS) in genomic selection has received much interest in both animal and plant breeding, because it is critical to the accuracy of the prediction models. In this study, five different TRS sampling algorithms, stratified sampling, mean of the coefficient of determination (CDmean), mean of predictor error variance (PEVmean), stratified CDmean (StratCDmean) and random sampling, were evaluated for prediction accuracy in the presence of different levels of population structure. In the presence of population structure, the most phenotypic variation captured by a sampling method in the TRS is desirable. The wheat dataset showed mild population structure, and CDmean and stratified CDmean methods showed the highest accuracies for all the traits except for test weight and heading date. The rice dataset had strong population structure and the approach based on stratified sampling showed the highest accuracies for all traits. In general, CDmean minimized the relationship between genotypes in the TRS, maximizing the relationship between TRS and the test set. This makes it suitable as an optimization criterion for long-term selection. Our results indicated that the best selection criterion used to optimize the TRS seems to depend on the interaction of trait architecture and population structure.

Double-diffusive convection and baroclinic instability in a differentially heated and initially stratified rotating system: the barostrat instability

NASA Astrophysics Data System (ADS)

Vincze, Miklos; Borcia, Ion; Harlander, Uwe; Le Gal, Patrice

2016-12-01

A water-filled differentially heated rotating annulus with initially prepared stable vertical salinity profiles is studied in the laboratory. Based on two-dimensional horizontal particle image velocimetry data and infrared camera visualizations, we describe the appearance and the characteristics of the baroclinic instability in this original configuration. First, we show that when the salinity profile is linear and confined between two non-stratified layers at top and bottom, only two separate shallow fluid layers can be destabilized. These unstable layers appear nearby the top and the bottom of the tank with a stratified motionless zone between them. This laboratory arrangement is thus particularly interesting to model geophysical or astrophysical situations where stratified regions are often juxtaposed to convective ones. Then, for more general but stable initial density profiles, statistical measures are introduced to quantify the extent of the baroclinic instability at given depths and to analyze the connections between this depth-dependence and the vertical salinity profiles. We find that, although the presence of stable stratification generally hinders full-depth overturning, double-diffusive convection can lead to development of multicellular sideways convection in shallow layers and subsequently to a multilayered baroclinic instability. Therefore we conclude that by decreasing the characteristic vertical scale of the flow, stratification may even enhance the formation of cyclonic and anticyclonic eddies (and thus, mixing) in a local sense.

Management of kidney cancer in Asia: resource-stratified guidelines from the Asian Oncology Summit 2012.

PubMed

Chiong, Edmund; Tay, Miah Hiang; Tan, Min Han; Kumar, Santosh; Sim, Hong Gee; Teh, Bin Tean; Umbas, Rainy; Chau, Noan Minh

2012-11-01

Treatment of renal-cell carcinoma has progressed over the past decade, in terms of surgical and systemic therapy. Current treatment guidelines are based on clinical evidence, but do not take into account resource limitations among different countries. These limitations, which include financial and logistical challenges and lack of skilled health-care professionals, have the greatest effect in low-income countries. This consolidated statement gives treatment recommendations for renal-cell carcinoma that are based on clinical evidence and stratified according to extent of resource availability. The statement was formulated by a panel of urologists, medical oncologists, and clinical oncologists from Asian countries, at a consensus session on kidney cancer that was held as part of the 2012 Asian Oncology Summit in Singapore. Resource levels are defined according to a four-tier system (basic, limited, enhanced, and maximum), and treatment recommendations are specified based on availability of financial, skill, and logistical resources. Copyright © 2012 Elsevier Ltd. All rights reserved.

Chemical discrimination of lubricant marketing types using direct analysis in real time time-of-flight mass spectrometry.

PubMed

Maric, Mark; Harvey, Lauren; Tomcsak, Maren; Solano, Angelique; Bridge, Candice

2017-06-30

In comparison to other violent crimes, sexual assaults suffer from very low prosecution and conviction rates especially in the absence of DNA evidence. As a result, the forensic community needs to utilize other forms of trace contact evidence, like lubricant evidence, in order to provide a link between the victim and the assailant. In this study, 90 personal bottled and condom lubricants from the three main marketing types, silicone-based, water-based and condoms, were characterized by direct analysis in real time time of flight mass spectrometry (DART-TOFMS). The instrumental data was analyzed by multivariate statistics including hierarchal cluster analysis, principal component analysis, and linear discriminant analysis. By interpreting the mass spectral data with multivariate statistics, 12 discrete groupings were identified, indicating inherent chemical diversity not only between but within the three main marketing groups. A number of unique chemical markers, both major and minor, were identified, other than the three main chemical components (i.e. PEG, PDMS and nonoxynol-9) currently used for lubricant classification. The data was validated by a stratified 20% withheld cross-validation which demonstrated that there was minimal overlap between the groupings. Based on the groupings identified and unique features of each group, a highly discriminating statistical model was then developed that aims to provide the foundation for the development of a forensic lubricant database that may eventually be applied to casework. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Early psychological interventions for posttraumatic stress, depression and anxiety after traumatic injury: A systematic review and meta-analysis.

PubMed

Giummarra, Melita J; Lennox, Alyse; Dali, Gezelle; Costa, Beth; Gabbe, Belinda J

2018-06-01

The psychological impacts of injury have significant long-term implications on injury recovery. This review examined the effectiveness of interventions delivered within three months of injury on reducing the severity of posttraumatic stress disorder (PTSD), anxiety and depression symptoms. A systematic search of seven databases (PsycINFO, Medline, Web of Science, CINAHL, Embase, Scopus and Cochrane Library) identified 15,224 records. 212 full-text articles were retrieved, 26 studies were included in narrative synthesis, and 12 studies with lower risk of bias were included in meta-analyses. Prolonged exposure, and cognitive and behavioural interventions elicited improvements in PTSD, anxiety and depression symptoms; multidisciplinary interventions improved PTSD and depression symptoms; and education-based interventions had little impact on any psychological symptoms. Studies comprising risk stratified or stepped care methods showed markedly greater population impact through better reach, implementation and adoption. Meta-analyses revealed small-medium reductions in PTSD symptoms over the first 12 months postinjury (SMD = 0.32 to 0.49) with clinically meaningful effects in 64% of studies; reduced depression symptoms at 0-3 (small effect; SMD = 0.34) and 6-12 months postinjury (medium effect; SMD = 0.60), with clinically meaningful effects in 40% of studies; but no pooled effects on anxiety symptoms at any time. Altogether, exposure- and CBT-based psychological interventions had the greatest impact on PTSD and depression symptoms postinjury when delivered within three months of injury, with risk-stratified, stepped care having the greatest population impact potential. Copyright © 2018 Elsevier Ltd. All rights reserved.

Leveling the field: addressing health disparities through diabetes disease management.

PubMed

White, Richard O; DeWalt, Darren A; Malone, Robert M; Osborn, Chandra Y; Pignone, Michael P; Rothman, Russell L

2010-01-01

To examine the relationships among patient characteristics, labor inputs, and improvement in glycosylated hemoglobin (A1C) level in a successful primary care-based diabetes disease management program (DDMP). We performed subanalyses to examine the relationships among patient characteristics, labor inputs, and improvement in A1C level within a randomized controlled trial. Control patients received usual care, while intervention patients received usual care plus a comprehensive DDMP. The primary outcome was improvement in A1C level over 12 months stratified by intervention status and patient characteristics. Process outcomes included the number of actions or contacts with patients, time spent with patients, and number of glucose medication titrations or additions. One hundred ninety-three of 217 enrolled patients (88.9%) had complete 12-month followup data. Patients in the intervention group had significantly greater improvement in A1C level than the control group (-2.1% vs -1.2%, P = .007). In multivariate analysis, no significant differences were observed in improvement in A1C level when stratified by age, race/ethnicity, income, or insurance status, and no interaction effect was observed between any covariate and intervention status. Among intervention patients, we observed similar labor inputs regardless of age, race/ethnicity, sex, education, or whether goal A1C level was achieved. Among intervention patients in a successful DDMP, improvement in A1C level was achieved regardless of age, race/ethnicity, sex, income, education, or insurance status. Labor inputs were similar regardless of age, race/ethnicity, sex, or education and may reflect the nondiscriminatory nature of providing algorithm-based disease management care.

The Associations between RNA Splicing Complex Gene SF3A1 Polymorphisms and Colorectal Cancer Risk in a Chinese Population.

PubMed

Chen, Xiaohua; Du, Hua; Liu, Binjian; Zou, Li; Chen, Wei; Yang, Yang; Zhu, Ying; Gong, Yajie; Tian, Jianbo; Li, Feng; Zhong, Shan

2015-01-01

Aberrant alternative splicing included alterations in components of the mRNA splicing machinery often occurred in colon cancer. However, the role of SF3A1, one key component of the mRNA splicing machinery, on colorectal cancer (CRC) risk was still not elucidated. We performed a hospital-based case-control study containing 801 CRC patients and 817 cancer-free controls to examine the association between SF3A1 polymorphisms and CRC risk in a Chinese population. Four candidate SNPs (rs10376, rs5753073, rs2839998 and rs2074733) were selected based on bioinformatics analysis and previous findings. The results showed no significant associations between these SNPs and CRC risk (P > 0.05). Besides, the stratified analysis based on the smoking and alcohol use status obtained no statistically significant results. Our study was the first one to investigate the association between SF3A1 polymorphisms and CRC risk. The results suggested these four SNPs in SF3A1 were not associated with CRC risk in a Chinese population, however, further more studies are needed to confirm our findings.

Trans-Ethnic Meta-Analysis Identifies Common and Rare Variants Associated with Hepatocyte Growth Factor Levels in the Multi-Ethnic Study of Atherosclerosis (MESA)

PubMed Central

Larson, Nicholas B.; Berardi, Cecilia; Decker, Paul A.; Wassel, Christina L.; Kirsch, Phillip S.; Pankow, James S.; Sale, Michele M.; de Andrade, Mariza; Sicotte, Hugues; Tang, Weihong; Hanson, Naomi Q.; Tsai, Michael Y.; Taylor, Kent D.; Bielinski, Suzette J.

2015-01-01

Summary Hepatocyte growth factor (HGF) is a mesenchyme-derived pleiotropic factor that regulates cell growth, motility, mitogenesis, and morphogenesis in a variety of cells, and increased serum levels of HGF have been linked to a number of clinical and subclinical cardiovascular disease phenotypes. However, little is currently known regarding what genetic factors influence HGF levels, despite evidence of substantial genetic contributions to HGF variation. Based upon ethnicity-stratified single-variant association analysis and trans-ethnic meta-analysis of 6201 participants of the Multi-Ethnic Study of Atherosclerosis (MESA), we discovered five statistically significant common and low-frequency variants: HGF missense polymorphism rs5745687 (p.E299K) as well as four variants (rs16844364, rs4690098, rs114303452, rs3748034) within or in proximity to HGFAC. We also identified two significant ethnicity-specific gene-level associations (A1BG in African Americans; FASN in Chinese Americans) based upon low-frequency/rare variants, while meta-analysis of gene-level results identified a significant association for HGFAC. However, identified single-variant associations explained modest proportions of the total trait variation and were not significantly associated with coronary artery calcium or coronary heart disease. Our findings indicate genetic factors influencing circulating HGF levels may be complex and ethnically diverse. PMID:25998175

On The Determination of Shadow Boundaries and Relevant Eigenrays For Sound Propagation In Stratified Moving Media

NASA Technical Reports Server (NTRS)

Mcaninch, Gerry L.; Heath, Stephanie L.

2006-01-01

The eiconal and ray equations for a stratified moving medium are analyzed to determine which rays connect a source located at an altitude z = z(sub s) to an observer on the ground plane. The characteristics of all available rays are ascertained. Further, the rays which determine the shadow boundary are found. Thus, the shadow boundary may be easily calculated and any observers for which an eigenray does not exist eliminated from further consideration. Therefore, the analysis may be applied to save computer time in two ways. First, rays that do not reach the ground may be eliminated before they are traced, and observers for which no eigenray exists may be eliminated from consideration.

Systematic review of fall risk screening tools for older patients in acute hospitals.

PubMed

Matarese, Maria; Ivziku, Dhurata; Bartolozzi, Francesco; Piredda, Michela; De Marinis, Maria Grazia

2015-06-01

To determine the most accurate fall risk screening tools for predicting falls among patients aged 65 years or older admitted to acute care hospitals. Falls represent a serious problem in older inpatients due to the potential physical, social, psychological and economic consequences. Older inpatients present with risk factors associated with age-related physiological and psychological changes as well as multiple morbidities. Thus, fall risk screening tools for older adults should include these specific risk factors. There are no published recommendations addressing what tools are appropriate for older hospitalized adults. Systematic review. MEDLINE, CINAHL and Cochrane electronic databases were searched between January 1981-April 2013. Only prospective validation studies reporting sensitivity and specificity values were included. Recommendations of the Cochrane Handbook of Diagnostic Test Accuracy Reviews have been followed. Three fall risk assessment tools were evaluated in seven articles. Due to the limited number of studies, meta-analysis was carried out only for the STRATIFY and Hendrich Fall Risk Model II. In the combined analysis, the Hendrich Fall Risk Model II demonstrated higher sensitivity than STRATIFY, while the STRATIFY showed higher specificity. In both tools, the Youden index showed low prognostic accuracy. The identified tools do not demonstrate predictive values as high as needed for identifying older inpatients at risk for falls. For this reason, no tool can be recommended for fall detection. More research is needed to evaluate fall risk screening tools for older inpatients. © 2014 John Wiley & Sons Ltd.

Design of dry sand soil stratified sampler

NASA Astrophysics Data System (ADS)

Li, Erkang; Chen, Wei; Feng, Xiao; Liao, Hongbo; Liang, Xiaodong

2018-04-01

This paper presents a design of a stratified sampler for dry sand soil, which can be used for stratified sampling of loose sand under certain conditions. Our group designed the mechanical structure of a portable, single - person, dry sandy soil stratified sampler. We have set up a mathematical model for the sampler. It lays the foundation for further development of design research.

An Analysis of the Status of Kentucky's Educational Adequacy Goal: A Five-Year Comparative Study of Academic Attainment and per Pupil Expenditures

ERIC Educational Resources Information Center

Chedester, Cheryl G. Moore

2012-01-01

Using an equal-group stratified sample of 42 Kentucky public P-12 school districts, the researcher conducted a quantitative correlational analysis to examine the relationship between per pupil expenditures in reading and mathematics proficiency. Repeated measures t tests analyzed the differences of the mean scores for the study variables of…

VALIDITY OF A TWO-DIMENSIONAL MODEL FOR VARIABLE-DENSITY HYDRODYNAMIC CIRCULATION

EPA Science Inventory

A three-dimensional model of temperatures and currents has been formulated to assist in the analysis and interpretation of the dynamics of stratified lakes. In this model, nonlinear eddy coefficients for viscosity and conductivities are included. A two-dimensional model (one vert...

Setting the stage for equity-sensitive monitoring of the maternal and child health Millennium Development Goals.

PubMed Central

Wirth, Meg E.; Balk, Deborah; Delamonica, Enrique; Storeygard, Adam; Sacks, Emma; Minujin, Alberto

2006-01-01

OBJECTIVE: This analysis seeks to set the stage for equity-sensitive monitoring of the health-related Millennium Development Goals (MDGs). METHODS: We use data from international household-level surveys (Demographic and Health Surveys (DHS) and Multiple Indicator Cluster Surveys (MICS)) to demonstrate that establishing an equity baseline is necessary and feasible, even in low-income and data-poor countries. We assess data from six countries using 11 health indicators and six social stratifiers. Simple bivariate stratification is complemented by simultaneous stratification to expose the compound effect of multiple forms of vulnerability. FINDINGS: The data reveal that inequities are complex and interactive: inferences cannot be drawn about the nature or extent of inequities in health outcomes from a single stratifier or indicator. CONCLUSION: The MDGs and other development initiatives must become more comprehensive and explicit in their analysis and tracking of inequities. The design of policies to narrow health gaps must take into account country-specific inequities. PMID:16878225

Prior pregnancy and antenatal rubella sero-negativity-evidence of persistent maternal immunologic alteration?

PubMed

Lao, Terence T; Hui, Annie S Y; Sahota, Daljit S

2017-09-01

It is unclear if the immunologic alterations induced by pregnancy could persist. Antenatal rubella sero-negativity was correlated with gravidity, abortions and parity in 112 083 gravidae managed during 1997-2015, with further analysis stratified for factors known to influence rubella serology. The 10.2% sero-negative gravidae had different characteristics, and the incidence showed significant difference and positive trend (P<.001 for both) with gravidity, abortions and parity. The pattern remained consistent when analysis was stratified for advanced age, high body mass index and medical history, but was negated by hepatitis B virus infection except for abortions, and by high body mass index for parity. For gravidity 2-4, no difference in rubella sero-negativity was found between gravidae with all previous pregnancies ended in abortion vs delivery. Prior pregnancies diminished rubella immunity in a dose-dependent manner, which may be a reflection of the cumulative effect of pregnancy-associated maternal immunologic alteration. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

English in the French Workplace: Realism and Anxieties

ERIC Educational Resources Information Center

Deneire, Marc

2008-01-01

The adoption of English as a corporate language in an increasingly large number of French companies has provoked various reactions ranging from enthusiastic embrace to strong rejection based on anxiety and cultural protectionism. This paper is an attempt to understand these reactions based on a stratified study of the extent to which English has…

Lake Superior Zooplankton Biomass Predictions from LOPC Tow Surveys Compare Well with a Probability Based Net Survey

EPA Science Inventory

We conducted a probability-based sampling of Lake Superior in 2006 and compared the zooplankton biomass estimate with laser optical plankton counter (LOPC) predictions. The net survey consisted of 52 sites stratified across three depth zones (0-30, 30-150, >150 m). The LOPC tow...

Alachlor transformation patterns in aquatic field mesocosms under variable oxygen and nutrient conditions

USGS Publications Warehouse

Graham, D.W.; Miley, M.K.; Denoyelles, F.; Smith, Val H.; Thurman, E.M.; Carter, R.

2000-01-01

Alachlor is one of the most commonly used herbicides in both Europe and North America. Because of its toxic properties, its fate and attenuation in natural waters is practically important. This paper assesses factors that affect alachlor decay rate in aquatic systems using field-scale experimental units. In particular, we used field mesocosms (11.3 m3 outdoor fiberglass tanks) to examine the affect of oxygen level and other factors on decay rate in water columns. This is one of the first studies ever performed where diverse water column conditions have been successfully simulated using common mesocosm-scale facilities. Four treatments were assessed, including aerobic systems (aerobic); low nutrient, oxygen-stratified systems (stratified-LN); moderate nutrient, oxygen-stratified systems (stratified-HN); and anaerobic systems (anaerobic). The lowest half-lives were observed in the anaerobic units (9.7 days) followed by the aerobic (21 days), stratified-HN (22 days), and stratified-LN (46 days) units. Our results indicate that alachlor is transformed most rapidly under anaerobic conditions, although the ambient phosphorus level also appears to influence decay rate. In this study, two common alachlor breakdown products, ethane sulfonic acid (ESA) and oxanilic acid, were also monitored. Oxanilic acid was produced in greater quantities than ESA under all treatments with the highest levels being produced in the stratified-HN units. In general, our results suggest that previous laboratory data, which indicated that high rates of alachlor decay can occur under oxygen-free methanogenic conditions, is translatable to field-scale applications. Copyright (C) 2000 Elsevier Science Ltd.Alachlor is one of the most commonly used herbicides in both Europe and North America. Because of its toxic properties, its fate and attenuation in natural waters is practically important. This paper assesses factors that affect alachlor decay rate in aquatic systems using field-scale experimental units. In particular, we used field mesocosms (11.3 m3 outdoor fiberglass tanks) to examine the affect of oxygen level and other factors on decay rate in water columns. This is one of the first studies ever performed where diverse water column conditions have been successfully simulated using common mesocosm-scale facilities. Four treatments were assessed, including aerobic systems (aerobic); low nutrient, oxygen-stratified systems (stratified-LN); moderate nutrient, oxygen-stratified systems (stratified-HN); and anaerobic systems (anaerobic). The lowest half-lives were observed in the anaerobic units (9.7 days) followed by the aerobic (21 days), stratified-HN (22 days), and stratified-LN (46 days) units. Our results indicate that alachlor is transformed most rapidly under anaerobic conditions, although the ambient phosphorus level also appears to influence decay rate. In this study, two common alachlor breakdown products, ethane sulfonic acid (ESA) and oxanilic acid, were also monitored. Oxanilic acid was produced in greater quantities than ESA under all treatments with the highest levels being produced in the stratified-HN units. In general, our results suggest that previous laboratory data, which indicated that high rates of alachlor decay can occur under oxygen-free methanogenic conditions, is translatable to field-scale applications.Aquatic field mesocosms were used to examine the influence of DO concentration and the presence of nutrients on alachlor transformation. Four treatments were used: wholly aerobic water columns, thermally and oxygen stratified water columns with low nutrient levels, stratified water columns with moderate nutrient levels, and wholly anaerobic water columns. The anaerobic treatment produced the highest rate of alachlor decay, followed by the aerobic and stratified treatments. The lowest decay rate occurred in the aerobic, low-nutrient stratified units.

A review of accuracy assessment for object-based image analysis: From per-pixel to per-polygon approaches

NASA Astrophysics Data System (ADS)

Ye, Su; Pontius, Robert Gilmore; Rakshit, Rahul

2018-07-01

Object-based image analysis (OBIA) has gained widespread popularity for creating maps from remotely sensed data. Researchers routinely claim that OBIA procedures outperform pixel-based procedures; however, it is not immediately obvious how to evaluate the degree to which an OBIA map compares to reference information in a manner that accounts for the fact that the OBIA map consists of objects that vary in size and shape. Our study reviews 209 journal articles concerning OBIA published between 2003 and 2017. We focus on the three stages of accuracy assessment: (1) sampling design, (2) response design and (3) accuracy analysis. First, we report the literature's overall characteristics concerning OBIA accuracy assessment. Simple random sampling was the most used method among probability sampling strategies, slightly more than stratified sampling. Office interpreted remotely sensed data was the dominant reference source. The literature reported accuracies ranging from 42% to 96%, with an average of 85%. A third of the articles failed to give sufficient information concerning accuracy methodology such as sampling scheme and sample size. We found few studies that focused specifically on the accuracy of the segmentation. Second, we identify a recent increase of OBIA articles in using per-polygon approaches compared to per-pixel approaches for accuracy assessment. We clarify the impacts of the per-pixel versus the per-polygon approaches respectively on sampling, response design and accuracy analysis. Our review defines the technical and methodological needs in the current per-polygon approaches, such as polygon-based sampling, analysis of mixed polygons, matching of mapped with reference polygons and assessment of segmentation accuracy. Our review summarizes and discusses the current issues in object-based accuracy assessment to provide guidance for improved accuracy assessments for OBIA.

Asymptomatic Ventricular Pre-excitation: Between Sudden Cardiac Death and Catheter Ablation.

PubMed

Brugada, Josep; Keegan, Roberto

2018-03-01

Debate about the best clinical approach to the management of asymptomatic patients with ventricular pre-excitation and advice on whether or not to invasively stratify and ablate is on-going. Weak evidence about the real risk of sudden cardiac death and the potential benefit of catheter ablation has probably prevented the clarification of action in this not infrequent and sometimes conflicting clinical situation. After analysing all available data, real evidence-based medicine could be the alternative strategy for managing this group of patients. According to recent surveys, most electrophysiologists invasively stratify. Based on all accepted risk factors - younger age, male, associated structural heart disease, posteroseptal localisation, ability of the accessory pathway to conduct anterogradely at short intervals of ≤250 milliseconds and inducibility of sustained atrioventricular re-entrant tachycardia and/or atrial fibrillation - a shared decisionmaking process on catheter ablation is proposed.

Asymptomatic Ventricular Pre-excitation: Between Sudden Cardiac Death and Catheter Ablation

PubMed Central

Brugada, Josep

2018-01-01

Debate about the best clinical approach to the management of asymptomatic patients with ventricular pre-excitation and advice on whether or not to invasively stratify and ablate is on-going. Weak evidence about the real risk of sudden cardiac death and the potential benefit of catheter ablation has probably prevented the clarification of action in this not infrequent and sometimes conflicting clinical situation. After analysing all available data, real evidence-based medicine could be the alternative strategy for managing this group of patients. According to recent surveys, most electrophysiologists invasively stratify. Based on all accepted risk factors – younger age, male, associated structural heart disease, posteroseptal localisation, ability of the accessory pathway to conduct anterogradely at short intervals of ≤250 milliseconds and inducibility of sustained atrioventricular re-entrant tachycardia and/or atrial fibrillation – a shared decisionmaking process on catheter ablation is proposed. PMID:29636970

Evaluation of SLAR and thematic mapper MSS data for forest cover mapping using computer-aided analysis techniques

NASA Technical Reports Server (NTRS)

Hoffer, R. M. (Principal Investigator); Knowlton, D. J.; Dean, M. E.

1981-01-01

A set of training statistics for the 30 meter resolution simulated thematic mapper MSS data was generated based on land use/land cover classes. In addition to this supervised data set, a nonsupervised multicluster block of training statistics is being defined in order to compare the classification results and evaluate the effect of the different training selection methods on classification performance. Two test data sets, defined using a stratified sampling procedure incorporating a grid system with dimensions of 50 lines by 50 columns, and another set based on an analyst supervised set of test fields were used to evaluate the classifications of the TMS data. The supervised training data set generated training statistics, and a per point Gaussian maximum likelihood classification of the 1979 TMS data was obtained. The August 1980 MSS data was radiometrically adjusted. The SAR data was redigitized and the SAR imagery was qualitatively analyzed.

Similarity Theory of Withdrawn Water Temperature Experiment

PubMed Central

2015-01-01

Selective withdrawal from a thermal stratified reservoir has been widely utilized in managing reservoir water withdrawal. Besides theoretical analysis and numerical simulation, model test was also necessary in studying the temperature of withdrawn water. However, information on the similarity theory of the withdrawn water temperature model remains lacking. Considering flow features of selective withdrawal, the similarity theory of the withdrawn water temperature model was analyzed theoretically based on the modification of governing equations, the Boussinesq approximation, and some simplifications. The similarity conditions between the model and the prototype were suggested. The conversion of withdrawn water temperature between the model and the prototype was proposed. Meanwhile, the fundamental theory of temperature distribution conversion was firstly proposed, which could significantly improve the experiment efficiency when the basic temperature of the model was different from the prototype. Based on the similarity theory, an experiment was performed on the withdrawn water temperature which was verified by numerical method. PMID:26065020

Which factor contribute most to empower farmers through e-Agriculture in Bangladesh?

PubMed

Rashid, Sheikh Mohammed Mamur; Islam, Md Rezwan; Quamruzzaman, Md

2016-01-01

The purpose of this research was designed to investigate the impact of e-Agriculture on farmers of Bangladesh. Empowerment is stratified as economic, family and social, political, knowledge and psychological empowerment. Data were collected in Bhatbour Block of Dhighi union under Sadar Upazila of Minikganj District. Data were collected in two phases from the same group of respondents (in August, 2013 and September, 2015). Two sample t test and step-wise multiple regression method were used for analysis. The results showed that e-Agriculture had significant impact on the empowerment of farmers of Bangladesh. Additionally, the study concluded that the most significant factor behind the empowerment of farmer was the use of e-Agriculture which could explain almost 84 % of the total variation of the empowerment. Based on the findings, it is recommended that government should implement e-Agriculture based projects on a massive scale for the empowerment of the farmers.

Coronary heart disease index based on longitudinal electrocardiography

NASA Technical Reports Server (NTRS)

Townsend, J. C.; Cronin, J. P.

1977-01-01

A coronary heart disease index was developed from longitudinal ECG (LCG) tracings to serve as a cardiac health measure in studies of working and, essentially, asymptomatic populations, such as pilots and executives. For a given subject, the index consisted of a composite score based on the presence of LCG aberrations and weighted values previously assigned to them. The index was validated by correlating it with the known presence or absence of CHD as determined by a complete physical examination, including treadmill, resting ECG, and risk factor information. The validating sample consisted of 111 subjects drawn by a stratified-random procedure from 5000 available case histories. The CHD index was found to be significantly more valid as a sole indicator of CHD than the LCG without the use of the index. The index consistently produced higher validity coefficients in identifying CHD than did treadmill testing, resting ECG, or risk factor analysis.

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

Baker, Erin Shammel; Burnum-Johnson, Kristin E.; Jacobs, Jon M.

Rapid diagnosis of disease states using less invasive, safer, and more clinically acceptable approaches than presently employed is an imperative goal for the field of medicine. While mass spectrometry (MS)-based proteomics approaches have attempted to meet these objectives, challenges such as the enormous dynamic range of protein concentrations in clinically relevant biofluid samples coupled with the need to address human biodiversity have slowed their employment. Herein, we report on the use of a new platform that addresses these challenges by coupling technical advances in rapid gas phase multiplexed ion mobility spectrometry (IMS) separations [1, 2] with liquid chromatography (LC) andmore » MS to dramatically increase measurement sensitivity and throughput, further enabling future MS-based clinical applications. An initial application of the LC-IMS-MS platform for the analysis of blood serum samples from stratified post-liver transplant patients with recurrent fibrosis progression illustrates its potential utility for disease characterization and use in personalized medicine [3, 4].« less

Mitigation of Atmospheric Delay in SAR Absolute Ranging Using Global Numerical Weather Prediction Data: Corner Reflector Experiments at 3 Different Test Sites

NASA Astrophysics Data System (ADS)

Cong, Xiaoying; Balss, Ulrich; Eineder, Michael

2015-04-01

The atmospheric delay due to vertical stratification, the so-called stratified atmospheric delay, has a great impact on both interferometric and absolute range measurements. In our current researches [1][2][3], centimeter-range accuracy has been proven based on Corner Reflector (CR) based measurements by applying atmospheric delay correction using the Zenith Path Delay (ZPD) corrections derived from nearby Global Positioning System (GPS) stations. For a global usage, an effective method has been introduced to estimate the stratified delay based on global 4-dimensional Numerical Weather Prediction (NWP) products: the direct integration method [4][5]. Two products, ERA-Interim and operational data, provided by European Centre for Medium-Range Weather Forecast (ECMWF) are used to integrate the stratified delay. In order to access the integration accuracy, a validation approach is investigated based on ZPD derived from six permanent GPS stations located in different meteorological conditions. Range accuracy at centimeter level is demonstrated using both ECMWF products. Further experiments have been carried out in order to determine the best interpolation method by analyzing the temporal and spatial correlation of atmospheric delay using both ECMWF and GPS ZPD. Finally, the integrated atmospheric delays in slant direction (Slant Path Delay, SPD) have been applied instead of the GPS ZPD for CR experiments at three different test sites with more than 200 TerraSAR-X High Resolution SpotLight (HRSL) images. The delay accuracy is around 1-3 cm depending on the location of test site due to the local water vapor variation and the acquisition time/date. [1] Eineder M., Minet C., Steigenberger P., et al. Imaging geodesy - Toward centimeter-level ranging accuracy with TerraSAR-X. Geoscience and Remote Sensing, IEEE Transactions on, 2011, 49(2): 661-671. [2] Balss U., Gisinger C., Cong X. Y., et al. Precise Measurements on the Absolute Localization Accuracy of TerraSAR-X on the Base of Far-Distributed Test Sites; EUSAR 2014; 10th European Conference on Synthetic Aperture Radar; Proceedings of. VDE, 2014: 1-4. [3] Eineder M., Balss U., Gisinger C., et al. TerraSAR-X pixel localization accuracy: Approaching the centimeter level, Geoscience and Remote Sensing Symposium (IGARSS), 2014 IEEE International. IEEE, 2014: 2669-2670. [4] Cong X., Balss U., Eineder M., et al. Imaging Geodesy -- Centimeter-Level Ranging Accuracy With TerraSAR-X: An Update. Geoscience and Remote Sensing Letters, IEEE, 2012, 9(5): 948-952. [5] Cong X. SAR Interferometry for Volcano Monitoring: 3D-PSI Analysis and Mitigation of Atmospheric Refractivity. München, Technische Universität München, Dissertation, 2014.

Thermal Non-equilibrium Revealed by Periodic Pulses of Random Amplitudes in Solar Coronal Loops

NASA Astrophysics Data System (ADS)

Auchère, F.; Froment, C.; Bocchialini, K.; Buchlin, E.; Solomon, J.

2016-08-01

We recently detected variations in extreme ultraviolet intensity in coronal loops repeating with periods of several hours. Models of loops including stratified and quasi-steady heating predict the development of a state of thermal non-equilibrium (TNE): cycles of evaporative upflows at the footpoints followed by falling condensations at the apex. Based on Fourier and wavelet analysis, we demonstrate that the observed periodic signals are indeed not signatures of vibrational modes. Instead, superimposed on the power law expected from the stochastic background emission, the power spectra of the time series exhibit the discrete harmonics and continua expected from periodic trains of pulses of random amplitudes. These characteristics reinforce our earlier interpretation of these pulsations as being aborted TNE cycles.

Thermal Non-Equilibrium Revealed by Periodic Pulses of Random Amplitudes in Solar Coronal Loops

NASA Astrophysics Data System (ADS)

Auchère, F.; Froment, C.; Bocchialini, K.; Buchlin, E.; Solomon, J.

2016-10-01

We recently detected variations in extreme ultraviolet intensity in coronal loops repeating with periods of several hours. Models of loops including stratified and quasi-steady heating predict the development of a state of thermal non-equilibrium (TNE): cycles of evaporative upflows at the footpoints followed by falling condensations at the apex. Based on Fourier and wavelet analysis, we demonstrate that the observed periodic signals are indeed not signatures of vibrational modes. Instead, superimposed on the power law expected from the stochastic background emission, the power spectra of the time series exhibit the discrete harmonics and continua expected from periodic trains of pulses of random amplitudes. These characteristics reinforce our earlier interpretation of these pulsations as being aborted TNE cycles.

[Study of spatial stratified sampling strategy of Oncomelania hupensis snail survey based on plant abundance].

PubMed

Xun-Ping, W; An, Z

2017-07-27

Objective To optimize and simplify the survey method of Oncomelania hupensis snails in marshland endemic regions of schistosomiasis, so as to improve the precision, efficiency and economy of the snail survey. Methods A snail sampling strategy (Spatial Sampling Scenario of Oncomelania based on Plant Abundance, SOPA) which took the plant abundance as auxiliary variable was explored and an experimental study in a 50 m×50 m plot in a marshland in the Poyang Lake region was performed. Firstly, the push broom surveyed data was stratified into 5 layers by the plant abundance data; then, the required numbers of optimal sampling points of each layer through Hammond McCullagh equation were calculated; thirdly, every sample point in the line with the Multiple Directional Interpolation (MDI) placement scheme was pinpointed; and finally, the comparison study among the outcomes of the spatial random sampling strategy, the traditional systematic sampling method, the spatial stratified sampling method, Sandwich spatial sampling and inference and SOPA was performed. Results The method (SOPA) proposed in this study had the minimal absolute error of 0.213 8; and the traditional systematic sampling method had the largest estimate, and the absolute error was 0.924 4. Conclusion The snail sampling strategy (SOPA) proposed in this study obtains the higher estimation accuracy than the other four methods.

[Identifying areas of epidemiological stratification in an onchocerciasis focus in Yanomami territory, Roraima, Brazil].

PubMed

Coelho, G E; Vieira, J B; Garcia-Zapata, M T; Schuertz, J C

1998-01-01

In this paper, aimed at suitable planning, analysis, and follow-up of treatment, control, and eradication in a human onchocerciasis program, were studied 27 geographic areas and examined 3,974 inhabitants. Four epidemiological areas with different prevalences were identified and stratified.

Characterization of aluminum nitride based films with high resolution X-ray fluorescence spectroscopy

NASA Astrophysics Data System (ADS)

Anagnostopoulos, D. F.; Siozios, A.; Patsalas, P.

2018-02-01

X-ray fluorescence spectra of Al based films are measured, using a lab-scale wavelength dispersive flat crystal spectrometer. Various structures of AlN films were studied, like single layered, capped, stratified, nanostructured, crystalline, or amorphous. By optimizing the set-up for enhanced energy resolution and detection efficiency, the measured line shapes of Κα, Kβ, and KLL radiative Auger transitions are shown to be adequately detailed to allow chemical characterization. The chemistry identification is based on the pattern comparison of the emitted line shape from the chemically unknown film and the reference line shapes from standard materials, recorded under identical experimental conditions. The ultimate strength of lab-scale high resolution X-ray fluorescence spectroscopy on film analysis is verified, in cases that ordinary applied techniques like X-ray photoelectron and X-ray diffraction fail, while the characterization refers to the non-destructive determination of the bulk properties of the film and not to its surface, as the probed depth is in the micrometer range.

The role of the complete Coriolis force in weakly stratified oceanic flows

NASA Astrophysics Data System (ADS)

Tort, M.; Winters, K. B.; Ribstein, B.; Zeitlin, V.

2016-02-01

Ocean dynamics is usually described using the primitive equations based on the so-called traditional approximation (TA), where the Coriolis force associated with the horizontal component of the planetary rotation is neglected (also called non-traditional (NT) part proportional to cosΦ, see Fig 1.). However, recent studies have shown that the NT part of the Coriolis force plays a non-negligible dynamical role in some particular oceanic flows (see Gerkema et al., 2008 for an extensive review of NT effects for geophysical and astrophysical flows). Here we explore the relevance of including the NT component of the Coriolis force in ocean models, by presenting particular results regarding two different mid-latitude flow configurations after relaxing the TA: Propagation of wind-induced near-inertial waves (NIWs). Under the TA, NIWs propagate toward the equator, the inertially poleward propagation being internally reflected at a depth-independent critical latitude. The combined effects of the NT Coriolis force and weak stratification in the deep ocean leads to the existence of waveguides for sub-inertial waves, which get trapped and propagate further poleward (Winters et al., 2011). Here we consider storm-induced NIWs and their evolution in a non-linear Boussinesq model on the β-plane in the NT approximation. Preliminary results are presented concerning the behavior of the waves in a weakly stratified mixed-layer, where NT effects are expected to be significant. Inertial instability. A detailed linear stability analysis of the Bickley jet at large Rossby numbers in the NT approximation on the f-plane is performed for long waves in a continuously stratified Boussinesq model. For a sufficiently weak stratification, both symmetric and asymmetric inertial instabilities have substantially higher growth rates than in the TA while no discernible differences between the two approximations are observed for strong enough stratifications (Tort et al., 2015).

Long-Term Survival Prediction for Coronary Artery Bypass Grafting: Validation of the ASCERT Model Compared With The Society of Thoracic Surgeons Predicted Risk of Mortality.

PubMed

Lancaster, Timothy S; Schill, Matthew R; Greenberg, Jason W; Ruaengsri, Chawannuch; Schuessler, Richard B; Lawton, Jennifer S; Maniar, Hersh S; Pasque, Michael K; Moon, Marc R; Damiano, Ralph J; Melby, Spencer J

2018-05-01

The recently developed American College of Cardiology Foundation-Society of Thoracic Surgeons (STS) Collaboration on the Comparative Effectiveness of Revascularization Strategy (ASCERT) Long-Term Survival Probability Calculator is a valuable addition to existing short-term risk-prediction tools for cardiac surgical procedures but has yet to be externally validated. Institutional data of 654 patients aged 65 years or older undergoing isolated coronary artery bypass grafting between 2005 and 2010 were reviewed. Predicted survival probabilities were calculated using the ASCERT model. Survival data were collected using the Social Security Death Index and institutional medical records. Model calibration and discrimination were assessed for the overall sample and for risk-stratified subgroups based on (1) ASCERT 7-year survival probability and (2) the predicted risk of mortality (PROM) from the STS Short-Term Risk Calculator. Logistic regression analysis was performed to evaluate additional perioperative variables contributing to death. Overall survival was 92.1% (569 of 597) at 1 year and 50.5% (164 of 325) at 7 years. Calibration assessment found no significant differences between predicted and actual survival curves for the overall sample or for the risk-stratified subgroups, whether stratified by predicted 7-year survival or by PROM. Discriminative performance was comparable between the ASCERT and PROM models for 7-year survival prediction (p < 0.001 for both; C-statistic = 0.815 for ASCERT and 0.781 for PROM). Prolonged ventilation, stroke, and hospital length of stay were also predictive of long-term death. The ASCERT survival probability calculator was externally validated for prediction of long-term survival after coronary artery bypass grafting in all risk groups. The widely used STS PROM performed comparably as a predictor of long-term survival. Both tools provide important information for preoperative decision making and patient counseling about potential outcomes after coronary artery bypass grafting. Copyright © 2018 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Computational Pathology to Discriminate Benign from Malignant Intraductal Proliferations of the Breast

PubMed Central

Oh, Eun-Yeong; Lerwill, Melinda F.; Brachtel, Elena F.; Jones, Nicholas C.; Knoblauch, Nicholas W.; Montaser-Kouhsari, Laleh; Johnson, Nicole B.; Rao, Luigi K. F.; Faulkner-Jones, Beverly; Wilbur, David C.; Schnitt, Stuart J.; Beck, Andrew H.

2014-01-01

The categorization of intraductal proliferative lesions of the breast based on routine light microscopic examination of histopathologic sections is in many cases challenging, even for experienced pathologists. The development of computational tools to aid pathologists in the characterization of these lesions would have great diagnostic and clinical value. As a first step to address this issue, we evaluated the ability of computational image analysis to accurately classify DCIS and UDH and to stratify nuclear grade within DCIS. Using 116 breast biopsies diagnosed as DCIS or UDH from the Massachusetts General Hospital (MGH), we developed a computational method to extract 392 features corresponding to the mean and standard deviation in nuclear size and shape, intensity, and texture across 8 color channels. We used L1-regularized logistic regression to build classification models to discriminate DCIS from UDH. The top-performing model contained 22 active features and achieved an AUC of 0.95 in cross-validation on the MGH data-set. We applied this model to an external validation set of 51 breast biopsies diagnosed as DCIS or UDH from the Beth Israel Deaconess Medical Center, and the model achieved an AUC of 0.86. The top-performing model contained active features from all color-spaces and from the three classes of features (morphology, intensity, and texture), suggesting the value of each for prediction. We built models to stratify grade within DCIS and obtained strong performance for stratifying low nuclear grade vs. high nuclear grade DCIS (AUC = 0.98 in cross-validation) with only moderate performance for discriminating low nuclear grade vs. intermediate nuclear grade and intermediate nuclear grade vs. high nuclear grade DCIS (AUC = 0.83 and 0.69, respectively). These data show that computational pathology models can robustly discriminate benign from malignant intraductal proliferative lesions of the breast and may aid pathologists in the diagnosis and classification of these lesions. PMID:25490766

Meta-analysis of neutropenia or leukopenia as a prognostic factor in patients with malignant disease undergoing chemotherapy.

PubMed

Shitara, Kohei; Matsuo, Keitaro; Oze, Isao; Mizota, Ayako; Kondo, Chihiro; Nomura, Motoo; Yokota, Tomoya; Takahari, Daisuke; Ura, Takashi; Muro, Kei

2011-08-01

We performed a systematic review and meta-analysis to determine the impact of neutropenia or leukopenia experienced during chemotherapy on survival. Eligible studies included prospective or retrospective analyses that evaluated neutropenia or leukopenia as a prognostic factor for overall survival or disease-free survival. Statistical analyses were conducted to calculate a summary hazard ratio and 95% confidence interval (CI) using random-effects or fixed-effects models based on the heterogeneity of the included studies. Thirteen trials were selected for the meta-analysis, with a total of 9,528 patients. The hazard ratio of death was 0.69 (95% CI, 0.64-0.75) for patients with higher-grade neutropenia or leukopenia compared to patients with lower-grade or lack of cytopenia. Our analysis was also stratified by statistical method (any statistical method to decrease lead-time bias; time-varying analysis or landmark analysis), but no differences were observed. Our results indicate that neutropenia or leukopenia experienced during chemotherapy is associated with improved survival in patients with advanced cancer or hematological malignancies undergoing chemotherapy. Future prospective analyses designed to investigate the potential impact of chemotherapy dose adjustment coupled with monitoring of neutropenia or leukopenia on survival are warranted.

Ancestry informative markers for distinguishing between Thai populations based on genome-wide association datasets

PubMed Central

Vongpaisarnsin, Kornkiat; Listman, Jennifer Beth; Malison, Robert T; Gelernter, Joel

2015-01-01

The main purpose of this work was to identify a set of AIMs that stratify the genetic structure and diversity of the Thai population from a high-throughput autosomal genome-wide association study. In this study, more than one million SNPs from the International HapMap database and the Thai depression genome-wide association study have been examined to identify ancestry informative markers (AIMs) that distinguish between Thai populations. An efficient strategy is proposed to identify and characterize such SNPs and to test high-resolution SNP data from international HapMap populations. The best AIMs are identified to stratify the population and to infer genetic ancestry structure. A total of 124 AIMs were clearly clustered geographically across the continent, whereas only 89 AIMs stratified the Thai population from East Asian populations. Finally, a set of 273 AIMs was able to distinguish northern from southern Thai subpopulations. These markers will be of particular value in identifying the ethnic origins in regions where matching by self-reports is unavailable or unreliable, which usually occurs in real forensic cases. PMID:25759192

Ancestry informative markers for distinguishing between Thai populations based on genome-wide association datasets.

PubMed

Vongpaisarnsin, Kornkiat; Listman, Jennifer Beth; Malison, Robert T; Gelernter, Joel

2015-07-01

The main purpose of this work was to identify a set of AIMs that stratify the genetic structure and diversity of the Thai population from a high-throughput autosomal genome-wide association study. In this study, more than one million SNPs from the international HapMap database and the Thai depression genome-wide association study have been examined to identify ancestry informative markers (AIMs) that distinguish between Thai populations. An efficient strategy is proposed to identify and characterize such SNPs and to test high-resolution SNP data from international HapMap populations. The best AIMs are identified to stratify the population and to infer genetic ancestry structure. A total of 124 AIMs were clearly clustered geographically across the continent, whereas only 89 AIMs stratified the Thai population from East Asian populations. Finally, a set of 273 AIMs was able to distinguish northern from southern Thai subpopulations. These markers will be of particular value in identifying the ethnic origins in regions where matching by self-reports is unavailable or unreliable, which usually occurs in real forensic cases. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Association between TNFA Gene Polymorphisms and Helicobacter pylori Infection: A Meta-Analysis

PubMed Central

Sun, Xudong; Xu, Yuanyuan; Wang, Li; Zhang, Fuhua; Zhang, Jinhua; Fu, Ximei; Jing, Tao; Han, Jian

2016-01-01

Background Several host genetic factors are thought to affect susceptibility to Helicobacter pylori infection-related diseases, including tumor necrosis factor (TNF)-α. Previous studies have evaluated the association between TNFA gene polymorphisms and H. pylori infection, but the results were inconclusive. We conducted this meta-analysis to clarify the association between TNFA polymorphisms and H. pylori infection. Methods Published literature within PubMed, Embase, and the Cochrane Library were used in our meta-analysis. Data were analyzed with the Stata13.1 software package using pooled odds ratios (ORs) with 95% confidence intervals (CI). Results A total of 24 studies were included in our study. The TNFA -308G>A polymorphism was associated with decreasing H. pylori infection (AA vs. AG+GG, OR = 0.64, 95% CI = 0.43–0.97; AA vs. GG, OR = 0.64, 95% CI = 0.43–0.97). A significantly decreased risk was also found for -1031T>C polymorphism (CC vs. CT+TT, OR = 0.61, 95% CI = 0.44–0.84). -863C>A polymorphism was associated with increasing risk of H. pylori infection (AA+AC vs. CC, OR = 1.47, 95% CI = 1.16–1.86; A allele vs. C allele, OR = 1.40, 95% CI = 1.14–1.72). There was no significant association between -857C>T polymorphism and H. pylori infection. When stratified analysis was conducted on H. pylori infection detection methods, -857C>T and -863C>A polymorphisms were associated with H. pylori infection for the non-ELISA subgroup. When stratified for ethnicity or study design, -863C>A significantly increased the risk and -1031T>C decreased the risk for the Asian subgroup and hospital-based subgroup. Conclusion Results of our meta-analysis demonstrate that TNFA -308G>A and -1031 T>C polymorphisms may be protective factors against H. pylori infection, and -863C>A may be a risk factor, especially in Asian populations. Further studies with larger sample sizes are required to validate these results. PMID:26815578

Cost-Savings Analysis of Renal Scintigraphy, Stratified by Renal Function Thresholds: Mercaptoacetyltriglycine Versus Diethylene Triamine Penta-Acetic Acid.

PubMed

Parikh, Kushal R; Davenport, Matthew S; Viglianti, Benjamin L; Hubers, David; Brown, Richard K J

2016-07-01

To determine the financial implications of switching technetium (Tc)-99m mercaptoacetyltriglycine (MAG-3) to Tc-99m diethylene triamine penta-acetic acid (DTPA) at certain renal function thresholds before renal scintigraphy. Institutional review board approval was obtained, and informed consent was waived for this HIPAA-compliant, retrospective, cohort study. Consecutive adult subjects (27 inpatients; 124 outpatients) who underwent MAG-3 renal scintigraphy, in the period from July 1, 2012 to June 30, 2013, were stratified retrospectively by hypothetical serum creatinine and estimated glomerular filtration rate (eGFR) thresholds, based on pre-procedure renal function. Thresholds were used to estimate the financial effects of using MAG-3 when renal function was at or worse than a given cutoff value, and DTPA otherwise. Cost analysis was performed with consideration of raw material and preparation costs, with radiotracer costs estimated by both vendor list pricing and proprietary institutional pricing. The primary outcome was a comparison of each hypothetical threshold to the clinical reality in which all subjects received MAG-3, and the results were supported by univariate sensitivity analysis. Annual cost savings by serum creatinine threshold were as follows (threshold given in mg/dL): $17,319 if ≥1.0; $33,015 if ≥1.5; and $35,180 if ≥2.0. Annual cost savings by eGFR threshold were as follows (threshold given in mL/min/1.73 m(2)): $21,649 if ≤60; $28,414 if ≤45; and $32,744 if ≤30. Cost-savings inflection points were approximately 1.25 mg/dL (serum creatinine) and 60 mL/min/1.73m(2) (eGFR). Secondary analysis by proprietary institutional pricing revealed similar trends, and cost savings of similar magnitude. Sensitivity analysis confirmed cost savings at all tested thresholds. Reserving MAG-3 utilization for patients who have impaired renal function can impart substantial annual cost savings to a radiology department. Copyright © 2016 American College of Radiology. Published by Elsevier Inc. All rights reserved.

Short-term effects of floods on Japanese encephalitis in Nanchong, China, 2007-2012: A time-stratified case-crossover study.

PubMed

Zhang, Feifei; Liu, Zhidong; Zhang, Caixia; Jiang, Baofa

2016-09-01

This time-stratified case-crossover study aimed to quantify the impact of floods on daily Japanese encephalitis (JE) cases from 2007 to 2012 in Nanchong city of Sichuan Province, China. Using conditional logistic regression analysis, we calculated the odds ratios (ORs) and 95% confidence intervals (CIs) at different lagged days, adjusting for daily average temperature (AT) and daily average relative humidity (ARH). A total of 370 JE cases were notified during the study period, with the median patient age being 4.2years. The seasonal pattern of JE cases clustered in July and August during the study period. Floods were significantly associated with an increased number of JE cases from lag 23 to lag 24, with the strongest lag effect at lag 23 (OR=2.00, 95% CI: 1.14-3.52). Similarly, AT and ARH were positively associated with daily JE cases from lag 0 to lag 8 and from lag 0 to lag 9, respectively. Floods, with AT and ARH, can be used to forecast JE outbreaks in the study area. Based on the results of this study, recommendations include undertaking control measures before the number of cases increases, especially for regions with similar geographic, climatic, and socio-economic conditions as those in the study area. Copyright © 2016 Elsevier B.V. All rights reserved.

Geographically-based discrimination is a social determinant of mental health in a deprived or stigmatized area in Japan: a cross-sectional study.

PubMed

Tabuchi, Takahiro; Fukuhara, Hiroyuki; Iso, Hiroyasu

2012-09-01

Perceived discrimination has been shown to be associated with health. However, it is uncertain whether discrimination based on geographical place of residence (geographically-based discrimination), such as Buraku or Nishinari discrimination in Japan, is associated with health. We conducted a cross-sectional study (response rate = 52.3%) from February to March 2009 in a Buraku district of Nishinari ward in Osaka city, one of the most deprived areas in Japan. We implemented sex-stratified and education-stratified multivariate regression models to examine the association between geographically-based discrimination and two mental health outcomes (depressive symptoms and diagnosis of mental illness) with adjustment for age, socioeconomic status, social relationships and lifestyle factors. A total of 1994 persons aged 25-79 years (928 men and 1066 women) living in the district were analyzed. In the fully-adjusted model, perceived geographically-based discrimination was significantly associated with depressive symptoms and diagnosis of mental illness. It was more strongly associated among men or highly educated people than among women or among less educated people. The effect of geographically-based discrimination on mental health is independent of socioeconomic status, social relationship and lifestyle factors. Geographically-based discrimination may be one of the social determinants of mental health. Copyright © 2012. Published by Elsevier Ltd.

Students Helping Students: Evaluating a Pilot Program of Peer Teaching for an Undergraduate Course in Human Anatomy

ERIC Educational Resources Information Center

Bruno, Paul A.; Love Green, Jennifer K.; Illerbrun, Sara L.; Holness, Duncan A.; Illerbrun, Samantha J.; Haus, Kara A.; Poirier, Sylvianne M.; Sveinson, Katherine L.

2016-01-01

The educational literature generally suggests that supplemental instruction (SI) is effective in improving academic performance in traditionally difficult courses. A pilot program of peer teaching based on the SI model was implemented for an undergraduate course in human anatomy. Students in the course were stratified into three groups based on…

Stratified Failure: Educational Stratification and Students' Attributions of Their Mathematics Performance in 24 Countries

ERIC Educational Resources Information Center

Mijs, Jonathan J. B.

2016-01-01

Country rankings based on the Programme for International Student Assessment (PISA) invite politicians and specialists to speculate about the reasons their countries did well or failed to do well. Rarely, however, do we hear from the students on whose performance these rankings are based. This omission is unfortunate for two reasons. First,…

Problem-Based Learning in an Eleventh Grade Chemistry Class: "Factors Affecting Cell Potential"

ERIC Educational Resources Information Center

Tarhan, Leman; Acar, Burcin

2007-01-01

The purpose of this research study was to examine the effectiveness of problem-based learning (PBL) on eleventh grade students' understanding of "The effects of temperature, concentration and pressure on cell potential" and also their social skills. Stratified randomly selected control and experimental groups with 20 students each were used in…

The Predictive Effects of Early Pregnancy Lipid Profiles and Fasting Glucose on the Risk of Gestational Diabetes Mellitus Stratified by Body Mass Index.

PubMed

Wang, Chen; Zhu, Weiwei; Wei, Yumei; Su, Rina; Feng, Hui; Lin, Li; Yang, Huixia

2016-01-01

This study aimed at evaluating the predictive effects of early pregnancy lipid profiles and fasting glucose on the risk of gestational diabetes mellitus (GDM) in patients stratified by prepregnancy body mass index (p-BMI) and to determine the optimal cut-off values of each indicator for different p-BMI ranges. A retrospective system cluster sampling survey was conducted in Beijing during 2013 and a total of 5,265 singleton pregnancies without prepregnancy diabetes were included. The information for each participant was collected individually using questionnaires and medical records. Logistic regression analysis and receiver operator characteristics analysis were used in the analysis. Outcomes showed that potential markers for the prediction of GDM include early pregnancy lipid profiles (cholesterol, triacylglycerols, low-density lipoprotein cholesterol/high-density lipoprotein cholesterol ratios [LDL-C/HDL-C], and triglyceride to high-density lipoprotein cholesterol ratios [TG/HDL-C]) and fasting glucose, of which fasting glucose level was the most accurate indicator. Furthermore, the predictive effects and cut-off values for these factors varied according to p-BMI. Thus, p-BMI should be a consideration for the risk assessment of pregnant patients for GDM development.

The effects of hydrological dynamics on benthic diatom community structure in a highly stratified estuary: The case of the Ebro Estuary (Catalonia, Spain)

NASA Astrophysics Data System (ADS)

Rovira, L.; Trobajo, R.; Leira, M.; Ibáñez, C.

2012-04-01

This study of the distribution of benthic diatom assemblages and their relationship with environmental factors in a highly stratified Mediterranean estuary, i.e. the Ebro Estuary, shows the importance of hydrological dynamics to explain the features of the diatom community in such an estuary, where river flow magnitude and fluctuations imply strong physicochemical variability especially in sites close to the sea. Eight sites along the estuary were sampled during 2007-2008 both at superficial and deep water layers, in order to gather both horizontal and vertical estuarine physicochemical and hydrological gradients. Canonical Variates Analysis and Hierarchical Cluster Analysis segregated diatom community in two assemblages depending on the dynamics of the salt-wedge. The diatom assemblages of riverine conditions (i.e. without salt-wedge influence) where characterised by high abundances of Cocconeis placentula var. euglypta and Amphora pediculus, meanwhile high abundances of Nizschia frustulum and Nitzschia inconspicua were characteristic of estuarine conditions (i.e. under salt-wedge influence). Redundancy Analysis showed that both diatom assemblages responded seasonally to Ebro River flows, especially in estuarine conditions, where fluctuating conditions affected diatom assemblages both at spatial and temporal scale.

Surface electrical properties experiment, Part 3

NASA Technical Reports Server (NTRS)

1974-01-01

A complete unified discussion of the electromagnetic response of a plane stratified structure is reported. A detailed and comprehensive analysis of the theoretical parts of the electromagnetic is given. The numerical problem of computing numbers of the electromagnetic field strengths is discussed. It is shown that the analysis of the conductive media is not very far removed from the theoretical analysis and the numerical difficulties are not as accute as for the low-loss problem. For Vol. 1, see N75-15570; for Vol. 2 see N75-15571.

Does educational attainment increase the risk of low back pain when genetics are considered? A population-based study of Spanish twins.

PubMed

Zadro, Joshua R; Shirley, Debra; Pinheiro, Marina B; Sánchez-Romera, Juan F; Pérez-Riquelme, Francisco; Ordoñana, Juan R; Ferreira, Paulo H

2017-04-01

There is limited research investigating educational attainment as a risk factor for low back pain (LBP), with the influence of gender commonly being neglected. Furthermore, genetics and early shared environment explain a substantial proportion of LBP cases and need to be controlled for when investigating risk factors for LBP. To investigate whether educational attainment affects the prevalence and risk of LBP differently in men and women while controlling for the influence of genetics and early shared environment. This is a cross-sectional and prospective twin case-control study. Adult monozygotic (MZ) and dizygotic (DZ) twins from the Murcia Twin Registry, with available data on educational attainment, formed the base sample for this study. The prevalence analysis considered twins with available data on LBP in 2013 (n=1,580). The longitudinal analysis considered twins free of LBP at baseline (2009-2011), with available data on LBP at follow-up (2013) (n=1,077). Data on the lifetime prevalence of activity limiting LBP (outcome) and educational attainment (risk factor) were self-reported. The prevalence analysis investigated the cross-sectional association between educational attainment and LBP, whereas the longitudinal analysis investigated whether educational attainment increased the risk of developing LBP. Both analyses were performed in the following sequence. First, a total sample analysis was performed on all twins (considering them as individuals), adjusting for confounding variables selected by the data. Second, to control for the influence of genetics and early shared environment, a within-pair case-control analysis (stratified by zygosity) was performed on complete twin pairs discordant for LBP (ie, one twin had LBP, whereas the co-twin did not). All analyses were stratified for gender where possible, with an interaction term determining whether gender was a significant moderator of the association between educational attainment and LBP. Women with either general secondary or university education were less likely to experience (prevalence analysis) or to develop LBP (longitudinal analysis). Educational attainment did not affect the risk of LBP in men. When controlling for the effects of genetics and early shared environment, the relationship between educational status and LBP in women was no longer statistically significant. Educational attainment affects LBP differently in men and women, with higher levels of education only decreasing the risk of developing LBP in women. After adjusting for genetics and early shared environment, the relationship between educational attainment and LBP in women disappears. This suggests that genetics and early shared environment are confounding the relationship between educational attainment and LBP in women. Copyright © 2016 Elsevier Inc. All rights reserved.

Causative factors and countermeasures for rural and suburban pedestrian accidents : accident data collection and analysis

DOT National Transportation Integrated Search

1977-03-01

The objectives of the study were to collect and analyze data on rural pedestrian accidents and to identify potential countermeasures. Data on a stratified random sample of over 1,500 rural and suburban accidents from six states was collected during i...

The Contours of Tracking in North Carolina

ERIC Educational Resources Information Center

Kelly, Sean

2007-01-01

In this analysis of North Carolina high schools the author examines school tracking policies using an amended version of Sorensen's (1970) conceptualization of the organizational dimensions of tracking. Data from curriculum guides in a stratified sample of 92 high schools reveal both consistency and variation in how tracking is implemented at the…

The Analysis of Iranian Students' Persistence in Online Education

ERIC Educational Resources Information Center

Mahmodi, Mahdi; Ebrahimzade, Issa

2015-01-01

In the following research, the relationship between instructional interaction and student persistence in e-learning has been analyzed. In order to conduct a descriptive-analytic survey, 744 undergraduate e-students were selected by stratified random sampling method to examine not only the frequency and the methods of establishing an instructional…

Causative factors and countermeasures for rural and suburban pedestrian accidents : accident data collection and analysis--appendices

DOT National Transportation Integrated Search

1977-06-01

The objectives of the study were to collect and analyze data on rural pedestrian accidents and to identify potential countermeasures. Data on a stratified random sample of over 1,500 rural and suburban accidents from six states was collected during i...

Prevalence rates of six selected infectious diseases among African migrants and refugees: a systematic review and meta-analysis.

PubMed

Chernet, A; Utzinger, J; Sydow, V; Probst-Hensch, N; Paris, D H; Labhardt, N D; Neumayr, A

2018-04-01

The objective of this paper was to systematically review the literature on the prevalence of selected infectious diseases among migrants/refugees of African origin and to provide policy makers and health care professionals with evidence-based information. We pursued a systematic review and meta-analysis to determine the prevalence of six selected infectious diseases (i.e., syphilis, helminthiasis, schistosomiasis, intestinal protozoa infections, hepatitis B, and hepatitis C) among migrants/refugees of African origin. Three electronic databases (i.e., PubMed, EMBASE, and ISI Web of Science) were searched without language restrictions. Relevant data were extracted and random-effects meta-analyses conducted. Only adjusted estimates were analyzed to help account for heterogeneity and potential confounding. We assessed the quality of evidence using the GRADE approach. The results were stratified by geographical region. Ninety-six studies were included. The evidence was of low quality due to the small numbers of countries, infectious diseases, and participants included. African migrants/refugees had median (with 95% confidence interval [95% CI]) prevalence for syphilis, helminthiasis, schistosomiasis, intestinal protozoa infection, hepatitis B, and hepatitis C of 6.0% [95% CI: 2.0-7.0%], 13.0% [95% CI: 9.5-14.5%], 14.0% [95% CI: 13.0-17.0%], 15.0% [95% CI: 10.5-21.0%], 10.0% [95% CI: 6.0-14.0%], and 3.0% [95% CI: 1.0-4.0%], respectively. We found high heterogeneity regardless of the disease (I 2 ; minimum 97.5%, maximum 99.7%). The relatively high prevalence of some infectious diseases among African migrants/refugees warrants for systematic screening. The large heterogeneity of the available published data does not allow for stratifying such screening programs according to the geographical origin of African migrants/refugees.

School Violence, Depressive Symptoms, and Help-seeking Behavior: A Gender-stratified Analysis of Biethnic Adolescents in South Korea.

PubMed

Kim, Ji-Hwan; Kim, Ja Young; Kim, Seung-Sup

2016-01-01

In South Korea (hereafter Korea), the number of adolescent offspring of immigrants has rapidly increased since the early 1990s, mainly due to international marriage. This research sought to examine the association between the experience of school violence and mental health outcomes, and the role of help-seeking behaviors in the association, among biethnic adolescents in Korea. We analyzed cross-sectional data of 3627 biethnic adolescents in Korea from the 2012 National Survey of Multicultural Families. Based on the victim's help-seeking behavior, adolescents who experienced school violence were classified into three groups: 'seeking help' group; 'feeling nothing' group; 'not seeking help' group. Multivariate logistic regression was applied to examine the associations between the experience of school violence and depressive symptoms for males and females separately. In the gender-stratified analysis, school violence was associated with depressive symptoms in the 'not seeking help' (odds ratio [OR], 7.05; 95% confidence interval [CI], 3.76 to 13.23) and the 'seeking help' group (OR, 2.77; 95% CI, 1.73 to 4.44) among male adolescents after adjusting for potential confounders, including the nationality of the immigrant parent and Korean language fluency. Similar associations were observed in the female groups. However, in the 'feeling nothing' group, the association was only significant for males (OR, 8.34; 95% CI, 2.82 to 24.69), but not females (OR, 0.77; 95% CI, 0.18 to 3.28). This study suggests that experience of school violence is associated with depressive symptoms and that the role of victims' help-seeking behaviors in the association may differ by gender among biethnic adolescents in Korea.

Age-specific impact of diabetes mellitus on the risk of cardiovascular mortality: An overview from the evidence for Cardiovascular Prevention from Observational Cohorts in the Japan Research Group (EPOCH-JAPAN).

PubMed

Hirakawa, Yoichiro; Ninomiya, Toshiharu; Kiyohara, Yutaka; Murakami, Yoshitaka; Saitoh, Shigeyuki; Nakagawa, Hideaki; Okayama, Akira; Tamakoshi, Akiko; Sakata, Kiyomi; Miura, Katsuyuki; Ueshima, Hirotsugu; Okamura, Tomonori

2017-03-01

Diabetes mellitus is a strong risk factor for cardiovascular disease. However, the age-specific association of diabetes with cardiovascular risk, especially in the elderly, remains unclear in non-Western populations. A pooled analysis was conducted using 8 cohort studies (mean follow-up period, 10.3 years) in Japan, combining the data from 38,854 individual participants without history of cardiovascular disease. In all, 1867 of the participants had diabetes, defined based on the 1998 World Health Organization criteria. The association between diabetes and the risk of death from cardiovascular disease, coronary heart disease (CHD), and stroke was estimated using a stratified Cox model, accounting for variability of baseline hazard functions among cohorts. During the follow-up, 1376 subjects died of cardiovascular disease (including 268 of coronary heart disease and 621 of stroke). Diabetes was associated with an increased risk of cardiovascular death after multivariable adjustment (hazard ratio [HR] 1.62; 95% confidence interval [CI], 1.35-1.94). Similarly, diabetes was a risk factor for CHD (HR 2.13; 95% CI, 1.47-3.09) and stroke (HR 1.40; 95% CI, 1.05-1.85). In the age-stratified analysis of the risk of cardiovascular death, the relative effects of diabetes were consistent across age groups (p for heterogeneity = 0.18), whereas the excess absolute risks of diabetes were greater in participants in their 70s and 80s than in younger subjects. The management of diabetes is important to reduce the risk of death from cardiovascular disease, not only in midlife but also in late life, in the Japanese population. Copyright © 2016. Production and hosting by Elsevier B.V.

Development of hypertension after long-term exposure to static magnetic fields among workers from a magnetic resonance imaging device manufacturing facility.

PubMed

Bongers, Suzan; Slottje, Pauline; Kromhout, Hans

2018-07-01

To assess the association between long-term exposure to static magnetic fields (SMF) in a magnetic resonance imaging (MRI)-manufacturing environment and hypertension. In an occupational cohort of male workers (n = 538) of an MRI-manufacturing facility, the first and last available blood pressure measurements from the facility's medical surveillance scheme were associated with modeled cumulative exposure to SMF. Exposure modeling was based on linkage of individual job histories from the facility's personnel records with a facility specific historical job exposure matrix. Hypertension was defined as a systolic pressure of above 140 mm Hg and/or a diastolic blood pressure above 90 mm Hg. Logistic regression models were used to associate cumulative SMF exposure to hypertension while adjusting for age, body mass index and blood pressure at time of first blood pressure measurement. Stratified analysis by exposure duration was performed similarly. High cumulative exposure to SMF (≥ 7.4 K Tesla minutes) was positively associated with development of hypertension (Odds Ratio [OR] 2.32, 95% confidence interval [CI] 1.27 - 4.25, P = 0.006). Stratified analysis showed a stronger association for those with high cumulative SMF exposure within a period up to 10 years (OR 3.96, 95% CI 1.62 - 9.69, P = 0.003), but no significant association was found for (high) cumulative exposure accumulated in a period of 10 or more years. Our findings suggest SMF exposure intensity to be more important than exposure duration for the risk of developing hypertension. Our data revealed that exposure to high levels of MRI-related SMF during MRI-manufacturing might be associated with developing hypertension. Copyright © 2018 Elsevier Inc. All rights reserved.

Comparative evidence of the consumption from fast-food restaurants between normal-weight and obese Saudi schoolchildren.

PubMed

Alturki, Hmidan A; Brookes, Denise Sk; Davies, Peter Sw

2018-04-06

To provide an in-depth analysis of the relationship between obesity and fast-food consumption by comparing urban obese and normal-weight Saudi Arabian children. A multicentre cross-sectional study was conducted from December 2015 to March 2016. Participants were divided into two groups (normal weight and obese) and further stratified by sex. Groups were randomly selected using a multistage stratified cluster-sampling technique. A self-paced questionnaire was used to collect data relating to food consumption. Weight height and waist circumference were measured and bioelectrical impedance analysis was performed in all children. Capital of Saudi Arabia, Riyadh. Children aged 9·00-11·99 years (n 1023). Compared with normal-weight groups, intake frequency of fast food/week was higher among the obese groups (P<0·001), irrespective of fast-food consumption outside (P<0·001) or inside (P<0·001) the home; and larger portion sizes were preferred in obese groups (P<0·001). Families eating fast-food meals together was a protective factor against obesity (OR; 95 % CI: 2·67; 1·44, 4·96, P<0·001), with similar results for families ordering from a 'healthy meals menu' for their children (1·90; 1·24, 2·90, P=0·002). Taste of fast foods (P=0·021), child-friendly menu (P=0·020) and meal cost (P<0·001) were identified as main reasons why parents took their children to fast-food restaurants; these data were replicated for parents with obese boys, but not girls. Development of effective interventions to reduce fast-food consumption in Saudi Arabian schoolchildren requires greater research-based evidence of fast-food consumption habits and practices associated with increased childhood obesity.

Exposure to negative acts and risk of turnover: a study of a register-based outcome among employees in three occupational groups.

PubMed

Clausen, Thomas; Hansen, Jørgen V; Hogh, Annie; Garde, Anne Helene; Persson, Roger; Conway, Paul Maurice; Grynderup, Matias; Hansen, Åse Marie; Rugulies, Reiner

2016-11-01

To investigate whether self-reported exposure to negative acts in the workplace (bullying and threats of violence) predicted turnover in three occupational groups (human service and sales workers, office workers and manual workers). Survey data on 2766 respondents were combined with data from a national labour force register to assess turnover. Mixed effects logistic regression analysis was used to examine the association between self-reported exposure to negative acts at baseline and risk of turnover after a 1-year follow-up. We found no significant associations between exposure to negative acts (bullying and threats of violence) and risk of turnover. When participants were stratified by occupational group and analyses were adjusted for age, gender, tenure and psychosocial working conditions, we found that exposure to bullying predicted risk of turnover in office workers (OR 2.03, 95 % CI 1.05-3.90), but neither in human service and sales workers, nor in manual workers. The association in office workers lost statistical significance when additionally adjusted for depressive symptoms (OR 1.77, 95 % CI 0.90-3.49). However, in a sensitivity analysis in which we used a 2-year (instead of a 1-year) follow-up period the association between bullying and turnover remained statistically significant in office workers even after adjusting for depressive symptoms (OR 2.10, 95 % CI 1.17-3.76). We found no statistically significant associations between threats of violence and risk of turnover in the stratified analyses. Exposure to bullying predicted risk of turnover among office workers but not among human service and sales workers and among manual workers. Threats of violence were not associated with turnover in any occupational group.

CT-Guided Microwave Ablation of 45 Renal Tumors: Analysis of Procedure Complexity Utilizing a Percutaneous Renal Ablation Complexity Scoring System.

PubMed

Mansilla, Alberto V; Bivins, Eugene E; Contreras, Francisco; Hernandez, Manuel A; Kohler, Nathan; Pepe, Julie W

2017-02-01

To develop a scoring system that stratifies complexity of percutaneous ablation of renal tumors. Analysis was performed of 36 consecutive patients (mean age, 64 y; range, 30-89 y) who underwent CT-guided microwave (MW) ablation of 45 renal tumors (mean tumor diameter, 2.4 cm; range, 1.2-4.0 cm). Technical success and effectiveness were determined based on intraprocedural and follow-up imaging studies. The RENAL score and the proposed percutaneous renal ablation complexity (P-RAC) score were calculated for each tumor. Technical success was 93.3% (n = 42). Biopsy of 38 of 45 renal tumors revealed 23 renal cell carcinomas. Median follow-up period was 9.7 months (range, 2.9-46.8 months). There were no tumor recurrences. One major complication, ureteropelvic junction stricture, occurred (2.6%). The P-RAC score was found to differ statistically from the RENAL score (t = 3.754, df = 44, P = .001). A positive correlation was found between the P-RAC score and number of antenna insertions (r = .378, n = 45, P = .011) and procedure duration (r = .328, n = 45, P = .028). No correlation was found between the RENAL score and number of MW antenna insertions (r = .110, n = 45, P = .472) or procedure duration (r = .263, n = 45, P = .081). Hydrodissection was significantly more common in the P-RAC high-complexity category than in low-complexity category (χ 2 = 12.073, df = 2, P = .002). The P-RAC score may be useful in stratifying percutaneous renal ablation complexity. Further studies with larger sample sizes are necessary to validate the P-RAC score and to determine if it can predict risk of complications. Copyright © 2016 SIR. Published by Elsevier Inc. All rights reserved.

The numerical study of the influence of rheological parameters stratified flows characteristics in cable dies

NASA Astrophysics Data System (ADS)

Kozitsyna, M. V.; Trufanova, N. M.

2017-01-01

Today the process of coextrusion is the most technological in the cable production with cross-linked polyethylene, composed of two or more layers of polymeric insulation. Since the covering technology is a simultaneous imposition of all necessary layers (two semiconducting shields on the insulation and conductor and one - on insulation), the main focus of this study is the analysis of significance of various factors influence on stratified flows characteristics. This paper has considered the flow of two abnormally viscous liquids in the cable head. The problem has been solved through a three-dimensional statement by applying the finite element method in the Ansys software package. The influence has been estimated by varying the rheological properties of materials to create all necessary layers thickness.

Economic viability of Stratified Medicine concepts: An investor perspective on drivers and conditions that favour using Stratified Medicine approaches in a cost-contained healthcare environment.

PubMed

Fugel, Hans-Joerg; Nuijten, Mark; Postma, Maarten

2016-12-25

Stratified Medicine (SM) is becoming a natural result of advances in biomedical science and a promising path for the innovation-based biopharmaceutical industry to create new investment opportunities. While the use of biomarkers to improve R&D efficiency and productivity is very much acknowledged by industry, much work remains to be done to understand the drivers and conditions that favour using a stratified approach to create economically viable products and to justify the investment in SM interventions as a stratification option. In this paper we apply a decision analytical methodology to address the economic attractiveness of different SM development options in a cost-contained healthcare environment. For this purpose, a hypothetical business case in the oncology market has been developed considering four feasible development scenarios. The article outlines the effects of development time and time to peak sales as key economic value drivers influencing profitability of SM interventions under specific conditions. If regulatory and reimbursement challenges can be solved, decreasing development time and enhancing early market penetration would most directly improve the economic attractiveness of SM interventions. Appropriate tailoring of highly differentiated patient subgroups is the prerequisite to leverage potential efficiency gains in the R&D process. Also, offering a better targeted and hence ultimately more cost-effective therapy at reimbursable prices will facilitate time to market access and allow increasing market share gains within the targeted populations. Copyright © 2016 Elsevier B.V. All rights reserved.

SU-E-J-219: A Dixon Based Pseudo-CT Generation Method for MR-Only Radiotherapy Treatment Planning of the Pelvis and Head and Neck

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

Maspero, M.; Meijer, G.J.; Lagendijk, J.J.W.

2015-06-15

Purpose: To develop an image processing method for MRI-based generation of electron density maps, known as pseudo-CT (pCT), without usage of model- or atlas-based segmentation, and to evaluate the method in the pelvic and head-neck region against CT. Methods: CT and MRI scans were obtained from the pelvic region of four patients in supine position using a flat table top only for CT. Stratified CT maps were generated by classifying each voxel based on HU ranges into one of four classes: air, adipose tissue, soft tissue or bone.A hierarchical region-selective algorithm, based on automatic thresholding and clustering, was used tomore » classify tissues from MR Dixon reconstructed fat, In-Phase (IP) and Opposed-Phase (OP) images. First, a body mask was obtained by thresholding the IP image. Subsequently, an automatic threshold on the Dixon fat image differentiated soft and adipose tissue. K-means clustering on IP and OP images resulted in a mask that, via a connected neighborhood analysis, allowing the user to select the components corresponding to bone structures.The pCT was estimated through assignment of bulk HU to the tissue classes. Bone-only Digital Reconstructed Radiographs (DRR) were generated as well. The pCT images were rigidly registered to the stratified CT to allow a volumetric and voxelwise comparison. Moreover, pCTs were also calculated within the head-neck region in two volunteers using the same pipeline. Results: The volumetric comparison resulted in differences <1% for each tissue class. A voxelwise comparison showed a good classification, ranging from 64% to 98%. The primary misclassified classes were adipose/soft tissue and bone/soft tissue. As the patients have been imaged on different table tops, part of the misclassification error can be explained by misregistration. Conclusion: The proposed approach does not rely on an anatomy model providing the flexibility to successfully generate the pCT in two different body sites. This research is founded by ZonMw IMDI Programme, project name: “RASOR sharp: MRI based radiotherapy planning using a single MRI sequence”, project number: 10-104003010.« less

Baroclinic Vortices in Rotating Stratified Shearing Flows: Cyclones, Anticyclones, and Zombie Vortices

NASA Astrophysics Data System (ADS)

Hassanzadeh, Pedram

Large coherent vortices are abundant in geophysical and astrophysical flows. They play significant roles in the Earth's oceans and atmosphere, the atmosphere of gas giants, such as Jupiter, and the protoplanetary disks around forming stars. These vortices are essentially three-dimensional (3D) and baroclinic, and their dynamics are strongly influenced by the rotation and density stratification of their environments. This work focuses on improving our understanding of the physics of 3D baroclinic vortices in rotating and continuously stratified flows using 3D spectral simulations of the Boussinesq equations, as well as simplified mathematical models. The first chapter discusses the big picture and summarizes the results of this work. In Chapter 2, we derive a relationship for the aspect ratio (i.e., vertical half-thickness over horizontal length scale) of steady and slowly-evolving baroclinic vortices in rotating stratified fluids. We show that the aspect ratio is a function of the Brunt-Vaisala frequencies within the vortex and outside the vortex, the Coriolis parameter, and the Rossby number of the vortex. This equation is basically the gradient-wind equation integrated over the vortex, and is significantly different from the previously proposed scaling laws that find the aspect ratio to be only a function of the properties of the background flow, and independent of the dynamics of the vortex. Our relation is valid for cyclones and anticyclones in either the cyclostrophic or geostrophic regimes; it works with vortices in Boussinesq fluids or ideal gases, and non-uniform background density gradient. The relation for the aspect ratio has many consequences for quasi-equilibrium vortices in rotating stratified flows. For example, cyclones must have interiors more stratified than the background flow (i.e., super-stratified), and weak anticyclones must have interiors less stratified than the background (i.e., sub-stratified). In addition, this equation is useful to infer the height and internal stratification of some astrophysical and geophysical vortices because direct measurements of their vertical structures are difficult. In Chapter 3, we show numerically and experimentally that localized suction in rotating continuously stratified flows produces three-dimensional baroclinic cyclones. As expected from Chapter 2, the interiors of these cyclones are super-stratified. Suction, modeled as a small spherical sink in the simulations, creates an anisotropic flow toward the sink with directional dependence changing with the ratio of the Coriolis parameter to the Brunt-Vaisala frequency. Around the sink, this flow generates cyclonic vorticity and deflects isopycnals so that the interior of the cyclone becomes super-stratified. The super-stratified region is visualized in the companion experiments that we helped to design and analyze using the synthetic schlieren technique. Once the suction stops, the cyclones decay due to viscous dissipation in the simulations and experiments. The numerical results show that the vertical velocity of viscously decaying cyclones flows away from the cyclone's midplane, while the radial velocity flows toward the cyclone's center. This observation is explained based on the cyclo-geostrophic balance. This vertical velocity mixes the flow inside and outside of cyclone and reduces the super-stratification. We speculate that the predominance of anticyclones in geophysical and astrophysical flows is due to the fact that anticyclones require sub-stratification, which occurs naturally by mixing, while cyclones require super-stratification. In Chapter 4, we show that a previously unknown instability creates space-filling lattices of 3D turbulent baroclinic vortices in linearly-stable, rotating, stratified shear flows. The instability starts from a newly discovered family of easily-excited critical layers. This new family, named the baroclinic critical layer, has singular vertical velocities; the traditional family of (barotropic) critical layer has singular stream-wise velocities and is hard to excite. In our simulations, the baroclinic critical layers in rotating stably-stratified linear shear are excited by small-volume, small-amplitude vortices or waves. The excited baroclinic critical layers then intensify by drawing energy from the background shear and roll-up into large coherent 3D vortices that excite new critical layers and vortices. The vortices self-similarly replicate to create lattices of turbulent vortices. These vortices persist for all time and are called zombie vortices because they can occur in the dead zones of protoplanetary disks. The self-replication of zombie vortices can de-stabilize the otherwise linearly and finite-amplitude stable Keplerian shear and lead to the formation of stars and planets. (Abstract shortened by UMI.)

Single Versus Double Lung Retransplantation Does Not Affect Survival Based on Previous Transplant Type.

PubMed

Schumer, Erin M; Rice, Jonathan D; Kistler, Amanda M; Trivedi, Jaimin R; Black, Matthew C; Bousamra, Michael; van Berkel, Victor

2017-01-01

Survival following retransplantation with a single lung is worse than after double lung transplant. We sought to characterize survival of patients who underwent lung retransplantation based on the type of their initial transplant, single or double. The United Network for Organ Sharing database was queried for adult patients who underwent lung retransplantation from 2005 onward. Patients were excluded if they underwent more than one retransplantation. The patient population was divided into 4 groups based on first followed by second transplant type, respectively: single then single, double then single, double then double, and single then double. Descriptive analysis and Kaplan-Meier survival analysis were performed. A p value less than 0.05 was considered significant. A total of 410 patients underwent retransplantation in the study time period. Overall mean survival for all patients who underwent retransplantation was 1,213 days. Kaplan-Meier survival analysis demonstrated no difference in graft survival between the 4 study groups (p = 0.146). There was no significant difference in graft survival between recipients of retransplant with single or double lungs when stratified by previous transplant type. These results suggest that when retransplantation is performed, single lung retransplantation should be considered, regardless of previous transplant type, in an effort to maximize organ resources. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Obesity as a risk factor for developing functional limitation among older adults: A conditional inference tree analysis.

PubMed

Cheng, Feon W; Gao, Xiang; Bao, Le; Mitchell, Diane C; Wood, Craig; Sliwinski, Martin J; Smiciklas-Wright, Helen; Still, Christopher D; Rolston, David D K; Jensen, Gordon L

2017-07-01

To examine the risk factors of developing functional decline and make probabilistic predictions by using a tree-based method that allows higher order polynomials and interactions of the risk factors. The conditional inference tree analysis, a data mining approach, was used to construct a risk stratification algorithm for developing functional limitation based on BMI and other potential risk factors for disability in 1,951 older adults without functional limitations at baseline (baseline age 73.1 ± 4.2 y). We also analyzed the data with multivariate stepwise logistic regression and compared the two approaches (e.g., cross-validation). Over a mean of 9.2 ± 1.7 years of follow-up, 221 individuals developed functional limitation. Higher BMI, age, and comorbidity were consistently identified as significant risk factors for functional decline using both methods. Based on these factors, individuals were stratified into four risk groups via the conditional inference tree analysis. Compared to the low-risk group, all other groups had a significantly higher risk of developing functional limitation. The odds ratio comparing two extreme categories was 9.09 (95% confidence interval: 4.68, 17.6). Higher BMI, age, and comorbid disease were consistently identified as significant risk factors for functional decline among older individuals across all approaches and analyses. © 2017 The Obesity Society.

Spatial Sampling of Weather Data for Regional Crop Yield Simulations

NASA Technical Reports Server (NTRS)

Van Bussel, Lenny G. J.; Ewert, Frank; Zhao, Gang; Hoffmann, Holger; Enders, Andreas; Wallach, Daniel; Asseng, Senthold; Baigorria, Guillermo A.; Basso, Bruno; Biernath, Christian;

Polymorphisms in tumor necrosis factor-alpha (-863C>A, -857C>T and +488G>A) are associated with idiopathic recurrent pregnancy loss in Korean women.

PubMed

Jang, Hyo Geun; Choi, Youngsok; Kim, Jung Oh; Jeon, Young Joo; Rah, HyungChul; Cho, Sung Hwan; Kim, Ji Hyang; Lee, Woo Sik; Kim, Nam Keun

2016-06-01

Polymorphisms in TNF-a have been reported as genetic risk factors for recurrent spontaneous abortion and TNF-α may be immunologically important. We therefore examined the contribution of several TNF-a mutations to this phenomenon. The study participants consisted of 388 patients with idiopathic recurrent pregnancy loss (RPL), which was diagnosed on the basis of at least two consecutive spontaneous abortions; control subjects were 224 healthy women with a history of successful pregnancies. Polymerase chain reaction-restriction fragment length polymorphism analysis was performed to determine the TNF-α -863C>A, -857C>T, and +488G>A genotypes. The TNF-α -863C>A variants correlated with increased risk of RPL (CA+AA; adjusted odds ratio [AOR], 2.142; 95% confidence interval [CI], 1.493-3.074). These data did not differ in a stratified analysis according to number of consecutive spontaneous abortions. In haplotype analysis, there were similar trends of data for combination analysis, but in patients with 3+ pregnancy losses, a stratified analysis revealed that this correlation did not increase directly with the number of pregnancy losses. The TNF-α -863C>A variant is a possible genetic risk factor for idiopathic RPL in Korean women. Copyright © 2016 American Society for Histocompatibility and Immunogenetics. Published by Elsevier Inc. All rights reserved.

Mediterranean Land Use and Land Cover Classification Assessment Using High Spatial Resolution Data

NASA Astrophysics Data System (ADS)

Elhag, Mohamed; Boteva, Silvena

2016-10-01

Landscape fragmentation is noticeably practiced in Mediterranean regions and imposes substantial complications in several satellite image classification methods. To some extent, high spatial resolution data were able to overcome such complications. For better classification performances in Land Use Land Cover (LULC) mapping, the current research adopts different classification methods comparison for LULC mapping using Sentinel-2 satellite as a source of high spatial resolution. Both of pixel-based and an object-based classification algorithms were assessed; the pixel-based approach employs Maximum Likelihood (ML), Artificial Neural Network (ANN) algorithms, Support Vector Machine (SVM), and, the object-based classification uses the Nearest Neighbour (NN) classifier. Stratified Masking Process (SMP) that integrates a ranking process within the classes based on spectral fluctuation of the sum of the training and testing sites was implemented. An analysis of the overall and individual accuracy of the classification results of all four methods reveals that the SVM classifier was the most efficient overall by distinguishing most of the classes with the highest accuracy. NN succeeded to deal with artificial surface classes in general while agriculture area classes, and forest and semi-natural area classes were segregated successfully with SVM. Furthermore, a comparative analysis indicates that the conventional classification method yielded better accuracy results than the SMP method overall with both classifiers used, ML and SVM.

Addition of 24-Hour Heart Rate Variability Parameters to the Cardiovascular Health Study Stroke Risk Score and Prediction of Incident Stroke: The Cardiovascular Health Study.

PubMed

Bodapati, Rohan K; Kizer, Jorge R; Kop, Willem J; Kamel, Hooman; Stein, Phyllis K

2017-07-21

Heart rate variability (HRV) characterizes cardiac autonomic functioning. The association of HRV with stroke is uncertain. We examined whether 24-hour HRV added predictive value to the Cardiovascular Health Study clinical stroke risk score (CHS-SCORE), previously developed at the baseline examination. N=884 stroke-free CHS participants (age 75.3±4.6), with 24-hour Holters adequate for HRV analysis at the 1994-1995 examination, had 68 strokes over ≤8 year follow-up (median 7.3 [interquartile range 7.1-7.6] years). The value of adding HRV to the CHS-SCORE was assessed with stepwise Cox regression analysis. The CHS-SCORE predicted incident stroke (HR=1.06 per unit increment, P =0.005). Two HRV parameters, decreased coefficient of variance of NN intervals (CV%, P =0.031) and decreased power law slope (SLOPE, P =0.033) also entered the model, but these did not significantly improve the c-statistic ( P =0.47). In a secondary analysis, dichotomization of CV% (LOWCV% ≤12.8%) was found to maximally stratify higher-risk participants after adjustment for CHS-SCORE. Similarly, dichotomizing SLOPE (LOWSLOPE <-1.4) maximally stratified higher-risk participants. When these HRV categories were combined (eg, HIGHCV% with HIGHSLOPE), the c-statistic for the model with the CHS-SCORE and combined HRV categories was 0.68, significantly higher than 0.61 for the CHS-SCORE alone ( P =0.02). In this sample of older adults, 2 HRV parameters, CV% and power law slope, emerged as significantly associated with incident stroke when added to a validated clinical risk score. After each parameter was dichotomized based on its optimal cut point in this sample, their composite significantly improved prediction of incident stroke during ≤8-year follow-up. These findings will require validation in separate, larger cohorts. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

Association of SLC6A4 variants with obsessive-compulsive disorder in a large multicenter US family study.

PubMed

Voyiaziakis, E; Evgrafov, O; Li, D; Yoon, H-J; Tabares, P; Samuels, J; Wang, Y; Riddle, M A; Grados, M A; Bienvenu, O J; Shugart, Y Y; Liang, K-Y; Greenberg, B D; Rasmussen, S A; Murphy, D L; Wendland, J R; McCracken, J T; Piacentini, J; Rauch, S L; Pauls, D L; Nestadt, G; Fyer, A J; Knowles, J A

2011-01-01

Genetic association studies of SLC6A4 (SERT) and obsessive-compulsive disorder (OCD) have been equivocal. We genotyped 1241 individuals in 278 pedigrees from the OCD Collaborative Genetics Study for 13 single-nucleotide polymorphisms, for the linked polymorphic region (LPR) indel with molecular haplotypes at rs25531, for VNTR polymorphisms in introns 2 and 7 and for a 381-bp deletion 3' to the LPR. We analyzed using the Family-Based Association Test (FBAT) under additive, dominant, recessive and genotypic models, using both OCD and sex-stratified OCD as phenotypes. Two-point FBAT analysis detected association between Int2 (P = 0.0089) and Int7 (P = 0.0187) (genotypic model). Sex-stratified two-point analysis showed strong association in females with Int2 (P<0.0002), significant after correction for linkage disequilibrium, and multiple marker and model testing (P(Adj) = 0.0069). The SLC6A4 gene is composed of two haplotype blocks (our data and the HapMap); FBAT whole-marker analysis conducted using this structure was not significant. Several noteworthy nonsignificant results have emerged. Unlike Hu et al., we found no evidence for overtransmission of the LPR L(A) allele (genotype relative risk = 1.11, 95% confidence interval: 0.77-1.60); however, rare individual haplotypes containing L(A) with P<0.05 were observed. Similarly, three individuals (two with OCD/OCPD) carried the rare I425V SLC6A4 variant, but none of them passed it on to their six OCD-affected offspring, suggesting that it is unlikely to be solely responsible for the 'OCD plus syndrome', as reported by Ozaki et al. In conclusion, we found evidence of genetic association at the SLC6A4 locus with OCD. A noteworthy lack of association at the LPR, LPR-rs25531 and rare 425V variants suggests that hypotheses about OCD risk need revision to accommodate these new findings, including a possible gender effect.

DWI-associated entire-tumor histogram analysis for the differentiation of low-grade prostate cancer from intermediate-high-grade prostate cancer.

PubMed

Wu, Chen-Jiang; Wang, Qing; Li, Hai; Wang, Xiao-Ning; Liu, Xi-Sheng; Shi, Hai-Bin; Zhang, Yu-Dong

2015-10-01

To investigate diagnostic efficiency of DWI using entire-tumor histogram analysis in differentiating the low-grade (LG) prostate cancer (PCa) from intermediate-high-grade (HG) PCa in comparison with conventional ROI-based measurement. DW images (b of 0-1400 s/mm(2)) from 126 pathology-confirmed PCa (diameter >0.5 cm) in 110 patients were retrospectively collected and processed by mono-exponential model. The measurement of tumor apparent diffusion coefficients (ADCs) was performed with using histogram-based and ROI-based approach, respectively. The diagnostic ability of ADCs from two methods for differentiating LG-PCa (Gleason score, GS ≤ 6) from HG-PCa (GS > 6) was determined by ROC regression, and compared by McNemar's test. There were 49 LG-tumor and 77 HG-tumor at pathologic findings. Histogram-based ADCs (mean, median, 10th and 90th) and ROI-based ADCs (mean) showed dominant relationships with ordinal GS of Pca (ρ = -0.225 to -0.406, p < 0.05). All above imaging indices reflected significant difference between LG-PCa and HG-PCa (all p values <0.01). Histogram 10th ADCs had dominantly high Az (0.738), Youden index (0.415), and positive likelihood ratio (LR+, 2.45) in stratifying tumor GS against mean, median and 90th ADCs, and ROI-based ADCs. Histogram mean, median, and 10th ADCs showed higher specificity (65.3%-74.1% vs. 44.9%, p < 0.01), but lower sensitivity (57.1%-71.3% vs. 84.4%, p < 0.05) than ROI-based ADCs in differentiating LG-PCa from HG-PCa. DWI-associated histogram analysis had higher specificity, Az, Youden index, and LR+ for differentiation of PCa Gleason grade than ROI-based approach.

Web-based Factors Affecting Online Purchasing Behaviour

NASA Astrophysics Data System (ADS)

Ariff, Mohd Shoki Md; Sze Yan, Ng; Zakuan, Norhayati; Zaidi Bahari, Ahamad; Jusoh, Ahmad

2013-06-01

The growing use of internet and online purchasing among young consumers in Malaysia provides a huge prospect in e-commerce market, specifically for B2C segment. In this market, if E-marketers know the web-based factors affecting online buyers' behaviour, and the effect of these factors on behaviour of online consumers, then they can develop their marketing strategies to convert potential customers into active one, while retaining existing online customers. Review of previous studies related to the online purchasing behaviour in B2C market has point out that the conceptualization and empirical validation of the online purchasing behaviour of Information and Communication Technology (ICT) literate users, or ICT professional, in Malaysia has not been clearly addressed. This paper focuses on (i) web-based factors which online buyers (ICT professional) keep in mind while shopping online; and (ii) the effect of web-based factors on online purchasing behaviour. Based on the extensive literature review, a conceptual framework of 24 items of five factors was constructed to determine web-based factors affecting online purchasing behaviour of ICT professional. Analysis of data was performed based on the 310 questionnaires, which were collected using a stratified random sampling method, from ICT undergraduate students in a public university in Malaysia. The Exploratory factor analysis performed showed that five factors affecting online purchase behaviour are Information Quality, Fulfilment/Reliability/Customer Service, Website Design, Quick and Details, and Privacy/Security. The result of Multiple Regression Analysis indicated that Information Quality, Quick and Details, and Privacy/Security affect positively online purchase behaviour. The results provide a usable model for measuring web-based factors affecting buyers' online purchase behaviour in B2C market, as well as for online shopping companies to focus on the factors that will increase customers' online purchase.

Patterns in bacterial and archaeal community structure and diversity in western Beaufort Sea sediments and waters

NASA Astrophysics Data System (ADS)

Hamdan, L. J.; Sikaroodi, M.; Coffin, R. B.; Gillevet, P. M.

2010-12-01

A culture-independent phylogenetic study of microbial communities in water samples and sediment cores recovered from the Beaufort Sea slope east of Point Barrow, Alaska was conducted. The goal of the work was to describe community composition in sediment and water samples and determine the influence of local environmental conditions on microbial populations. Archaeal and bacterial community composition was studied using length heterogeneity-polymerase chain reaction (LH-PCR) and multitag pyrosequencing (MTPS). Sediment samples were obtained from three piston cores on the slope (~1000m depth) arrayed along an east-west transect and one core from a depth of approximately 2000m. Discrete water samples were obtained using a CTD-rosette from three locations adjacent to piston core sites. Water sample were selected at three discrete depths within a vertically stratified (density) water column. The microbial community in near surface waters was distinct from the community observed in deeper stratified layers of the water column. Multidimensional scaling analysis (MDS) revealed that water samples from mid and deep stratified layers bore high similarity to communities in cores collected in close proximity. Overall, the highest diversity (bacteria and archaea) was observed in a core which had elevated methane concentration relative to other locations. Geochemical (e.g., bulk organic and inorganic carbon pools, nutrients, metabolites) and physical data (e.g. depth, water content) were used to reveal the abiotic factors structuring microbial communities. The analysis indicates that sediment water content (porosity) and inorganic carbon concentration are the most significant structuring elements on Beaufort shelf sedimentary microbial communities.

Gender adjustment or stratification in discerning upper extremity musculoskeletal disorder risk?

PubMed

Silverstein, Barbara; Fan, Z Joyce; Smith, Caroline K; Bao, Stephen; Howard, Ninica; Spielholz, Peregrin; Bonauto, David; Viikari-Juntura, Eira

2009-03-01

The aim was to explore whether "adjustment" for gender masks important exposure differences between men and women in a study of rotator cuff syndrome (RCS) and carpal tunnel syndrome (CTS) and work exposures. This cross-sectional study of 733 subjects in 12 health care and manufacturing workplaces used detailed individual health and work exposure assessment methods. Multiple logistic regression analysis was used to compare gender stratified and adjusted models. Prevalence of RCS and CTS among women was 7.1% and 11.3% respectively, and among men 7.8% and 6.4%. In adjusted (gender, age, body mass index) multivariate analyses of RCS and CTS, gender was not statistically significantly different. For RCS, upper arm flexion >/=45 degrees and forceful pinch increased the odds in the gender-adjusted model (OR 2.66, 95% CI 1.26-5.59) but primarily among women in the stratified analysis (OR 6.68, 95% CI 1.81-24.66 versus OR 1.45, 95% CI 0.53-4.00). For CTS, wrist radial/ulnar deviation >/=4% time and lifting >/=4.5kg >3% time, the adjusted OR was higher for women (OR 4.85, 95% CI 2.12-11.11) and in the gender stratified analyses, the odds were increased for both genders (women OR 5.18, 95% CI 1.70-15.81 and men OR 3.63, 95% CI 1.08-12.18). Gender differences in response to physical work exposures may reflect gender segregation in work and potential differences in pinch and lifting capacity. Reduction in these exposures may reduce prevalence of upper extremity disorders for all workers.

Body mass index and risk of BPH: a meta-analysis.

PubMed

Wang, S; Mao, Q; Lin, Y; Wu, J; Wang, X; Zheng, X; Xie, L

2012-09-01

Epidemiological studies have reported conflicting results relating obesity to BPH. A meta-analysis of cohort and case-control studies was conducted to pool the risk estimates of the association between obesity and BPH. Eligible studies were retrieved by both computer searches and review of references. We analyzed abstracted data with random effects models to obtain the summary risk estimates. Dose-response meta-analysis was performed for studies reporting categorical risk estimates for a series of exposure levels. A total of 19 studies met the inclusion criteria of the meta-analysis. Positive association with body mass index (BMI) was observed in BPH and lower urinary tract symptoms (LUTS) combined group (odds ratio=1.27, 95% confidence intervals 1.05-1.53). In subgroup analysis, BMI exhibited a positive dose-response relationship with BPH/LUTS in population-based case-control studies and a marginal positive association was observed between risk of BPH and increased BMI. However, no association between BPH/LUTS and BMI was observed in other subgroups stratified by study design, geographical region or primary outcome. The overall current literatures suggested that BMI was associated with increased risk of BPH. Further efforts should be made to confirm these findings and clarify the underlying biological mechanisms.

PLUME DISPERSION IN STABLY STRATIFIED FLOWS OVER COMPLEX TERRAIN, PHASE 2

EPA Science Inventory

Laboratory experiments were conducted in a stratified towing tank to investigate plume dispersion in stably stratified flows. First, plume dispersion over an idealized terrain model with a simulated elevated inversion in the atmosphere was investigated. These results were compare...

Management of adult and paediatric acute lymphoblastic leukaemia in Asia: resource-stratified guidelines from the Asian Oncology Summit 2013

PubMed Central

Yeoh, Allen EJ; Tan, Daryl; Li, Chi-Kong; Hori, Hiroki; Tse, Eric; Pui, Ching-Hon

2014-01-01

The survival rates for both adult and children with acute lymphoblastic leukaemia have improved substantially in recent years with wider use of improved risk-directed therapy and supportive care. In nearly all developed countries, clinical practice guidelines have been formulated by multidisciplinary panels of leukaemia experts, with the goal of providing recommendations on standard treatment approaches based on current evidence. However, those guidelines do not take into account resource limitations in low-income countries, including financial and technical challenges. In Asia, there are huge disparities in economy and infrastructure among the countries, and even among different regions in some large countries. This review summarizes the recommendations developed for Asian countries by a panel of adult and paediatric leukaemia therapists, based on the availability of financial, skill and logistical resources, at a consensus session held as part of the 2013 Asian Oncology Summit in Bangkok, Thailand. The management strategies described here are stratified by a four-tier system (basic, limited, enhanced and maximum) based on the resources available to a particular country or region. PMID:24176570

Perioperative Serum Lipid Status and Statin Use Affect the Revision Surgery Rate After Arthroscopic Rotator Cuff Repair.

PubMed

Cancienne, Jourdan M; Brockmeier, Stephen F; Rodeo, Scott A; Werner, Brian C

2017-11-01

Recent animal studies have demonstrated that hyperlipidemia is associated with poor tendon-bone healing after rotator cuff repair; however, these findings have not been substantiated in human studies. To examine any association between hyperlipidemia and the failure of arthroscopic rotator cuff repair requiring revision surgery and to investigate whether the use of statin lipid-lowering agents had any influence on observed associations. Cohort study; Level of evidence, 3. From a national insurance database, patients who underwent arthroscopic rotator cuff repair with perioperative lipid levels (total cholesterol, low-density lipoprotein [LDL], and triglycerides) recorded were reviewed. For each lipid test, patients were stratified into normal, moderate, and high groups based on published standards. For the total cholesterol and LDL cohorts, a subgroup analysis of patients stratified by statin use was performed. The primary outcome measure was ipsilateral revision rotator cuff surgery, including revision repair or debridement. A logistic regression analysis controlling for patient demographics and comorbidities was utilized for comparison. There were 30,638 patients included in the study. The rate of revision rotator cuff surgery was significantly increased in patients with moderate (odds ratio [OR], 1.20; 95% CI, 1.03-1.40; P = .022) and high total cholesterol levels (OR, 1.36; 95% CI, 1.10-1.55; P = .006) compared with patients with normal total cholesterol levels perioperatively. Within each of these groups, patients without statin use had significantly higher rates of revision surgery, while those with statin prescriptions did not. The absolute risk reduction for statin use ranged from 0.24% to 1.87% when stratified by the total cholesterol level, yielding a number needed to treat from 54 to 408 patients. The rate of revision surgery was significantly increased in patients with moderate (OR, 1.24; 95% CI, 1.10-1.41; P = .001) and high LDL levels (OR, 1.46; 95% CI, 1.08-1.99; P = .014) compared with patients with normal LDL levels perioperatively. Again, patients without statin prescriptions had significantly increased rates of revision surgery, whereas patients with statin use did not. The absolute risk reduction for statin use ranged from 0.26% to 1.89% when stratified by the LDL level, yielding a number needed to treat from 53 to 387 patients. There were no significant differences in the rates of revision rotator cuff surgery between patients with moderate and high triglyceride levels compared with patients with normal triglyceride levels. The present study found a significant association between moderate and high perioperative total cholesterol and LDL levels and the rate of revision surgery after primary arthroscopic rotator cuff repair. Furthermore, the use of statin agents appeared to mitigate the need for revision rotator cuff repair. Further prospective studies are necessary to validate these preliminary findings and determine if better perioperative lipid control can improve clinical outcomes after arthroscopic rotator cuff repair.

Assessing soil carbon vulnerability in the Western USA by geospatial modeling of pyrogenic and particulate carbon stocks

NASA Astrophysics Data System (ADS)

Ahmed, Zia U.; Woodbury, Peter B.; Sanderman, Jonathan; Hawke, Bruce; Jauss, Verena; Solomon, Dawit; Lehmann, Johannes

2017-02-01

To predict how land management practices and climate change will affect soil carbon cycling, improved understanding of factors controlling soil organic carbon fractions at large spatial scales is needed. We analyzed total soil organic (SOC) as well as pyrogenic (PyC), particulate (POC), and other soil organic carbon (OOC) fractions in surface layers from 650 stratified-sampling locations throughout Colorado, Kansas, New Mexico, and Wyoming. PyC varied from 0.29 to 18.0 mg C g-1 soil with a mean of 4.05 mg C g-1 soil. The mean PyC was 34.6% of the SOC and ranged from 11.8 to 96.6%. Both POC and PyC were highest in forests and canyon bottoms. In the best random forest regression model, normalized vegetation index (NDVI), mean annual precipitation (MAP), mean annual temperature (MAT), and elevation were ranked as the top four important variables determining PyC and POC variability. Random forests regression kriging (RFK) with environmental covariables improved predictions over ordinary kriging by 20 and 7% for PyC and POC, respectively. Based on RFK, 8% of the study area was dominated (≥50% of SOC) by PyC and less than 1% was dominated by POC. Furthermore, based on spatial analysis of the ratio of POC to PyC, we estimated that about 16% of the study area is medium to highly vulnerable to SOC mineralization in surface soil. These are the first results to characterize PyC and POC stocks geospatially using stratified sampling scheme at the scale of 1,000,000 km2, and the methods are scalable to other regions.

Proposal of a new stage grouping of gastric cancer for TNM classification: International Gastric Cancer Association staging project.

PubMed

Sano, Takeshi; Coit, Daniel G; Kim, Hyung Ho; Roviello, Franco; Kassab, Paulo; Wittekind, Christian; Yamamoto, Yuko; Ohashi, Yasuo

2017-03-01

The current AJCC staging system for gastric cancer (AJCC7) incorporated several major revisions to the previous edition. The T and N categories and the stage groups were newly defined, and adenocarcinoma of the esophagogastric junction (EGJ) was reclassified and staged according to the esophageal system. Studies to validate these changes showed inconsistent results. The International Gastric Cancer Association (IGCA) launched a project to support evidence-based revisions to the next edition of the AJCC staging system. Clinical and pathological data on patients who underwent curative gastrectomy at 59 institutions in 15 countries between 2000 and 2004 were retrospectively collected. Patients lost to follow-up within 5 years of surgery were excluded. Patients treated with neoadjuvant therapy were excluded. The data were analyzed in total, and separately by region of treatment. Of 25,411 eligible cases, 84.8 % were submitted from 24 institutions of Japan and Korea, 6.4 % from other Asian countries, and 8.8 % from 29 Western institutions. The T and N categories of AJCC7 clearly stratified the patient survival. Patients with pN3a and pN3b showed distinct prognosis in all regions, and by introducing pN3a and pN3b into a cluster analysis, we established a new stage grouping with better stratification than AJCC7, especially among stage III subgroups. Survival of Siewert type 2 and 3 EGJ tumors was better stratified by this IGCA stage grouping than by either esophageal or gastric scheme of AJCC7. For the next revision of AJCC classification, we propose a new stage grouping based on a large, worldwide data collection.

Generation of 2D Land Cover Maps for Urban Areas Using Decision Tree Classification

NASA Astrophysics Data System (ADS)

Höhle, J.

2014-09-01

A 2D land cover map can automatically and efficiently be generated from high-resolution multispectral aerial images. First, a digital surface model is produced and each cell of the elevation model is then supplemented with attributes. A decision tree classification is applied to extract map objects like buildings, roads, grassland, trees, hedges, and walls from such an "intelligent" point cloud. The decision tree is derived from training areas which borders are digitized on top of a false-colour orthoimage. The produced 2D land cover map with six classes is then subsequently refined by using image analysis techniques. The proposed methodology is described step by step. The classification, assessment, and refinement is carried out by the open source software "R"; the generation of the dense and accurate digital surface model by the "Match-T DSM" program of the Trimble Company. A practical example of a 2D land cover map generation is carried out. Images of a multispectral medium-format aerial camera covering an urban area in Switzerland are used. The assessment of the produced land cover map is based on class-wise stratified sampling where reference values of samples are determined by means of stereo-observations of false-colour stereopairs. The stratified statistical assessment of the produced land cover map with six classes and based on 91 points per class reveals a high thematic accuracy for classes "building" (99 %, 95 % CI: 95 %-100 %) and "road and parking lot" (90 %, 95 % CI: 83 %-95 %). Some other accuracy measures (overall accuracy, kappa value) and their 95 % confidence intervals are derived as well. The proposed methodology has a high potential for automation and fast processing and may be applied to other scenes and sensors.

Individuals With Type 2 Diabetes Mellitus Are at an Increased Risk of Gout But This Is Not Due to Diabetes: A Population-Based Cohort Study.

PubMed

Wijnands, José Maria Andreas; van Durme, Caroline Marie Pierre Ghislaine; Driessen, Johanna Hendrika Maria; Boonen, Annelies; Klop, Corinne; Leufkens, Bert; Cooper, Cyrus; Stehouwer, Coen Dirk Adriaan; de Vries, Frank

2015-08-01

The relationship between type 2 diabetes and gout is complex. The objective of this study was to understand the role of diabetes itself and its comorbidities within the association between type 2 diabetes and gout.We conducted a retrospective cohort study using the UK Clinical Practice Research Datalink (CPRD) GOLD. Persons with type 2 diabetes were identified as persons on a noninsulin antidiabetic drug (NIAD) between 2004 and 2012, and were matched to 1 control based on age, sex, and general practice. We estimated gout risk in NIAD users using Cox regression analysis. All analyses were stratified for sex.In total, 221,117 NIAD users were identified. NIAD users had an increased risk of gout (hazard ratio (HR) 1.48; 95% CI 1.41-1.54). This association was stronger in women (HR 2.23; 95% CI 2.07-2.41) compared with men (HR 1.19; 95% CI 1.13-1.26). After adjustments for BMI, eGFR, hypertension, renal transplantation, diuretics, statins, low-dose aspirin, ciclosporin, and tacrolimus, the risk disappeared in women (HR 1.01; 95% CI 0.92-1.11) and reversed in men (HR 0.61; 95% CI 0.58-0.66) (P for interaction <0.001). When stratifying gout risk according to HbA1c in male and female NIAD users, we found an inverse association between raising HbA1c and incident gout in men only. Further adjustment gave similar results.Individuals with type 2 diabetes are at increased risk of gout. This is not due to diabetes itself, but to the comorbid conditions. Diabetes itself is apparently associated with a decreased risk of gout, especially in men.

Air pollution from industrial waste gas emissions is associated with cancer incidences in Shanghai, China.

PubMed

Cong, Xiaowei

2018-05-01

Outdoor air pollution may be associated with cancer risk at different sites. This study sought to investigate outdoor air pollution from waste gas emission effects on multiple cancer incidences in a retrospective population-based study in Shanghai, China. Trends in cancer incidence for males and females and trends in waste gas emissions for the total waste gas, industrial waste gas, other waste gas, SO 2 , and soot were investigated between 1983 and 2010 in Shanghai, China. Regression models after adjusting for confounding variables were constructed to estimate associations between waste gas emissions and multiple cancer incidences in the whole group and stratified by sex, Engel coefficient, life expectancy, and number of doctors per 10,000 populations to further explore whether changes of waste gas emissions were associated with multiple cancer incidences. More than 550,000 new cancer patients were enrolled and reviewed. Upward trends in multiple cancer incidences for males and females and in waste gas emissions were observed from 1983 to 2010 in Shanghai, China. Waste gas emissions came mainly from industrial waste gas. Waste gas emissions was significantly positively associated with cancer incidence of salivary gland, small intestine, colorectal, anus, gallbladder, thoracic organs, connective and soft tissue, prostate, kidney, bladder, thyroid, non-Hodgkin's lymphoma, lymphatic leukemia, myeloid leukemia, and other unspecified sites (all p < 0.05). Negative association between waste gas emissions and the esophagus cancer incidence was observed (p < 0.05). The results of the whole group were basically consistent with the results of the stratified analysis. The results from this retrospective population-based study suggest ambient air pollution from waste gas emissions was associated with multiple cancer incidences.

Do Men and Women Need to Be Screened Differently with Fecal Immunochemical Testing? A Cost-Effectiveness Analysis.

PubMed

Meulen, Miriam P van der; Kapidzic, Atija; Leerdam, Monique E van; van der Steen, Alex; Kuipers, Ernst J; Spaander, Manon C W; de Koning, Harry J; Hol, Lieke; Lansdorp-Vogelaar, Iris

2017-08-01

Background: Several studies suggest that test characteristics for the fecal immunochemical test (FIT) differ by gender, triggering a debate on whether men and women should be screened differently. We used the microsimulation model MISCAN-Colon to evaluate whether screening stratified by gender is cost-effective. Methods: We estimated gender-specific FIT characteristics based on first-round positivity and detection rates observed in a FIT screening pilot (CORERO-1). Subsequently, we used the model to estimate harms, benefits, and costs of 480 gender-specific FIT screening strategies and compared them with uniform screening. Results: Biennial FIT screening from ages 50 to 75 was less effective in women than men [35.7 vs. 49.0 quality-adjusted life years (QALY) gained, respectively] at higher costs (€42,161 vs. -€5,471, respectively). However, the incremental QALYs gained and costs of annual screening compared with biennial screening were more similar for both genders (8.7 QALYs gained and €26,394 for women vs. 6.7 QALYs gained and €20,863 for men). Considering all evaluated screening strategies, optimal gender-based screening yielded at most 7% more QALYs gained than optimal uniform screening and even resulted in equal costs and QALYs gained from a willingness-to-pay threshold of €1,300. Conclusions: FIT screening is less effective in women, but the incremental cost-effectiveness is similar in men and women. Consequently, screening stratified by gender is not more cost-effective than uniform FIT screening. Impact: Our conclusions support the current policy of uniform FIT screening. Cancer Epidemiol Biomarkers Prev; 26(8); 1328-36. ©2017 AACR . ©2017 American Association for Cancer Research.

Establishing the minimal clinically important difference for the Questionnaire of Olfactory Disorders.

PubMed

Mattos, Jose L; Schlosser, Rodney J; Mace, Jess C; Smith, Timothy L; Soler, Zachary M

2018-05-02

Olfactory-specific quality of life (QOL) can be measured using the Questionnaire of Olfactory Disorders Negative Statements (QOD-NS). Changes in the QOD-NS after treatment can be difficult to interpret since there is no standardized definition of clinically meaningful improvement. Patients with chronic rhinosinusitis (CRS) completed the QOD-NS. Four distribution-based methods were used to calculate the minimal clinically important difference (MCID): (1) one-half standard deviation (SD); (2) standard error of the mean (SEM); (3) Cohen's effect size (d) of the smallest unit of change; and (4) minimal detectable change (MDC). We also averaged all 4 of the scores together. Finally, the likelihood of achieving a MCID after sinus surgery using these methods, as well as average QOD-NS scores, was stratified by normal vs abnormal baseline QOD-NS scores. Outcomes were examined on 128 patients. The mean ± SD improvement in QOD-NS score after surgery was 4.3 ± 11.0 for the entire cohort and 9.6 ± 12.9 for those with abnormal baseline scores (p < 0.001). The MCID values using the different techniques were: (1) SD = 6.5; (2) SEM = 3.1; (3) d = 2.6; and (4) MDC = 8.6. The MCID score was 5.2 on average. For the total cohort analysis, the likelihood of reporting a MCID ranged from 26% to 51%, and 49% to 70% for patients reporting preoperative abnormal olfaction. Distribution-based MCID values of the QOD-NS range between 2.6 and 8.6 points, with an average of 5.2. When stratified by preoperative QOD-NS scores the majority of patients reporting abnormal preoperative QOD-NS scores achieved a MCID. © 2018 ARS-AAOA, LLC.

A generalised model of secondary circulation for a wide range of geophysical flows from direct observations of natural turbidity currents

NASA Astrophysics Data System (ADS)

Azpiroz, M.; Cartigny, M.; Sumner, E. J.; Talling, P.; Parsons, D. R.; Clare, M. A.; Cooper, C.

2017-12-01

Turbidity currents transport sediment through submarine channel systems for hundreds of kilometres to form vast deposits of sediment in the deep sea called submarine fans. The largest submarine fans are fed by meandering channels suggesting that bends may enhance sediment transport distances. The interaction between meander bends and turbidity currents has been a topic of intense debate. Due to the absence of observations of deep-sea turbidity currents flowing through meander bends, our understanding has been based on experimental and numerical models. Measurements of geophysical flows demonstrate a common helical flow structure around meanders. Previous work has demonstrated that helical circulation in rivers is dominated by a single helix that rotates towards the inner bend at near-bed depths. In contrast, initial numerical and experimental models for turbidity currents found both river-like and river-reversed circulations. Saline flows in well-mixed estuaries show a river-like basal helical circulation, while stratified estuaries and saline flows are river-reversed. The existence of lateral stratification in stratified flows is thought to be the key factor in the change of direction of rotation. Stratification causes lateral pressure gradients that can govern the rotation of the flow helix. Turbidity currents are stratified due to their upwards-decreasing sediment load. It has therefore been proposed that stratified turbidity currents behave like stratified saline flow, but this hypothesis remains so far untested. Here we present the first observations of the helical flow in turbidity currents, which occurred within the deep-sea Congo Canyon. The measurements show a consistent river-reversed pattern downstream of the bend apex. Those results lead us to develop a new generalised model for a wide range of flows around meanders. Our conclusions have implications for understanding the flow erosional and depositional patterns, the evolution of channel systems and the architecture of the depositional record.

Health/functioning characteristics, gambling behaviors and gambling-related motivations in adolescents stratified by gambling problem severity: Findings from a high-school survey

PubMed Central

Yip, Sarah W.; Desai, Rani A.; Steinberg, Marvin A.; Rugle, Loreen; Cavallo, Dana A.; Krishnan-Sarin, Suchitra; Potenza, Marc N.

2013-01-01

In adults, different levels of gambling problem severity are differentially associated with measures of health and general functioning, gambling behaviors and gambling-related motivations. Here we present data from a survey of 2,484 Connecticut high school students, and investigate the data stratifying by gambling problem severity based on DSM-IV criteria for pathological gambling. Problem/pathological gambling was associated with a range of negative functions; e.g., poor academic performance, substance use, dysphoria/depression, and aggression. These findings suggest a need for improved interventions related to adolescent gambling and a need for additional research into the relationship (e.g., mediating factors) between gambling and risk and protective behaviors. PMID:21999494

Management of prostate cancer in Asia: resource-stratified guidelines from the Asian Oncology Summit 2013.

PubMed

Williams, Scott; Chiong, Edmund; Lojanapiwat, Bannakij; Umbas, Rainy; Akaza, Hideyuki

2013-11-01

Many local and systemic options for prostate cancer have emerged in recent years, but existing management guidelines do not account for diversity in health resources between different countries. We present recommendations for the management of prostate cancer, stratified according to the extent of resource availability-based on a four-tier system of basic, limited, enhanced, and maximum resources-to enable applicability to Asian countries with differing levels of health-care resources. This statement of recommendations was formulated by a multidisciplinary panel from Asia-Pacific countries, at a consensus session on prostate cancer that was held as part of the 2013 Asian Oncology Summit in Bangkok, Thailand. Copyright © 2013 Elsevier Ltd. All rights reserved.

Strongly Stratified Turbulence Wakes and Mixing Produced by Fractal Wakes

NASA Astrophysics Data System (ADS)

Dimitrieva, Natalia; Redondo, Jose Manuel; Chashechkin, Yuli; Fraunie, Philippe; Velascos, David

2017-04-01

This paper describes Shliering and Shadowgraph experiments of the wake induced mixing produced by tranversing a vertical or horizontal fractal grid through the interfase between two miscible fluids at low Atwood and Reynolds numbers. This is a configuration design to models the mixing across isopycnals in stably-stratified flows in many environmental relevant situations (either in the atmosphere or in the ocean. The initial unstable stratification is characterized by a reduced gravity: g' = gΔρ ρ where g is gravity, Δρ being the initial density step and ρ the reference density. Here the Atwood number is A = g' _ 2 g . The topology of the fractal wake within the strong stratification, and the internal wave field produces both a turbulent cascade and a wave cascade, with frecuen parametric resonances, the envelope of the mixing front is found to follow a complex non steady 3rd order polinomial function with a maximum at about 4-5 Brunt-Vaisalla non-dimensional time scales: t/N δ = c1(t/N) + c2g Δρ ρ (t/N)2 -c3(t/N)3. Conductivity probes and Shliering and Shadowgraph visual techniques, including CIV with (Laser induced fluorescence and digitization of the light attenuation across the tank) are used in order to investigate the density gradients and the three-dimensionality of the expanding and contracting wake. Fractal analysis is also used in order to estimate the fastest and slowest growing wavelengths. The large scale structures are observed to increase in wave-length as the mixing progresses, and the processes involved in this increase in scale are also examined.Measurements of the pointwise and horizontally averaged concentrations confirm the picture obtained from past flow visualization studies. They show that the fluid passes through the mixing region with relatively small amounts of molecular mixing,and the molecular effects only dominate on longer time scales when the small scales have penetrated through the large scale structures. The Non-stationary dynamicss and structure of stratified fluid flows around a wedge were also studied based of the fundamental equations set using numerical modeling. Due to breaking of naturally existing background diffusion flux of stratifying agent by an impermeable surface of the wedge a complex multi-level vortex system of compensatory fluid motions is formed around the obstacle. The flow is characterized by a wide range of values of internal scales that are absent in a homogeneous liquid. Numerical solution of the fundamental system with the boundary conditions is constructed using a solver such as stratifiedFoam developed within the frame of the open source computational package OpenFOAM using the finite volume method. The computations were performed in parallel using computing resources of the Scientific Research Supercomputer Complex of MSU (SRCC MSU) and the technological platform UniHUB. The evolution of the flow pattern of the wedge by stratified flow has been demonstrated. The complex structure of the fields of physical quantities and their gradients has been shown. Observed in experiment are multiple flow components, including upstream disturbances, internal waves and the downstream wake with submerged transient vortices well reproduced. Structural elements of flow differ in size and laws of variation in space and time. Rich fine flow structure visualized in vicinity and far from the obstacle. The global efficiency of the mixing process is measured and compared with previous estimates of mixing efficiency.

Cardiac imaging: working towards fully-automated machine analysis & interpretation.

PubMed

Slomka, Piotr J; Dey, Damini; Sitek, Arkadiusz; Motwani, Manish; Berman, Daniel S; Germano, Guido

2017-03-01

Non-invasive imaging plays a critical role in managing patients with cardiovascular disease. Although subjective visual interpretation remains the clinical mainstay, quantitative analysis facilitates objective, evidence-based management, and advances in clinical research. This has driven developments in computing and software tools aimed at achieving fully automated image processing and quantitative analysis. In parallel, machine learning techniques have been used to rapidly integrate large amounts of clinical and quantitative imaging data to provide highly personalized individual patient-based conclusions. Areas covered: This review summarizes recent advances in automated quantitative imaging in cardiology and describes the latest techniques which incorporate machine learning principles. The review focuses on the cardiac imaging techniques which are in wide clinical use. It also discusses key issues and obstacles for these tools to become utilized in mainstream clinical practice. Expert commentary: Fully-automated processing and high-level computer interpretation of cardiac imaging are becoming a reality. Application of machine learning to the vast amounts of quantitative data generated per scan and integration with clinical data also facilitates a move to more patient-specific interpretation. These developments are unlikely to replace interpreting physicians but will provide them with highly accurate tools to detect disease, risk-stratify, and optimize patient-specific treatment. However, with each technological advance, we move further from human dependence and closer to fully-automated machine interpretation.

US forests are showing increased rates of decline in response to a changing climate

Treesearch

Warren B. Cohen; Zhiqiang Yang; David M. Bell; Stephen V. Stehman

2015-01-01

How vulnerable are US forest to a changing climate? We answer this question using Landsat time series data and a unique interpretation approach, TimeSync, a plot-based Landsat visualization and data collection tool. Original analyses were based on a stratified two-stage cluster sample design that included interpretation of 3858 forested plots. From these data, we...

Web-Based Tutoring of the Structure Strategy with or without Elaborated Feedback or Choice for Fifth- and Seventh-Grade Readers

ERIC Educational Resources Information Center

Meyer, Bonnie J. F.; Wijekumar, Kay; Middlemiss, Wendy; Higley, Kelli; Lei, Pui-Wa; Meier, Catherine; Spielvogel, James

2010-01-01

This study investigated the effects of different versions of Web-based instruction focused on text structure on fifth- and seventh-grade students' reading comprehension. Stratified random assignment was employed in a two-factor experiment embedded within a pretest and multiple posttests design (immediate and four-month delayed posttests). The two…

Crystal Identification in Dual-Layer-Offset DOI-PET Detectors Using Stratified Peak Tracking Based on SVD and Mean-Shift Algorithm

NASA Astrophysics Data System (ADS)

Wei, Qingyang; Dai, Tiantian; Ma, Tianyu; Liu, Yaqiang; Gu, Yu

2016-10-01

An Anger-logic based pixelated PET detector block requires a crystal position map (CPM) to assign the position of each detected event to a most probable crystal index. Accurate assignments are crucial to PET imaging performance. In this paper, we present a novel automatic approach to generate the CPMs for dual-layer offset (DLO) PET detectors using a stratified peak tracking method. In which, the top and bottom layers are distinguished by their intensity difference and the peaks of the top and bottom layers are tracked based on a singular value decomposition (SVD) and mean-shift algorithm in succession. The CPM is created by classifying each pixel to its nearest peak and assigning the pixel with the crystal index of that peak. A Matlab-based graphical user interface program was developed including the automatic algorithm and a manual interaction procedure. The algorithm was tested for three DLO PET detector blocks. Results show that the proposed method exhibits good performance as well as robustness for all the three blocks. Compared to the existing methods, our approach can directly distinguish the layer and crystal indices using the information of intensity and offset grid pattern.

Classification of drugs with different risk profiles.

PubMed

Saedder, Eva Aggerholm; Brock, Birgitte; Nielsen, Lars Peter; Bonnerup, Dorthe Krogsgaard; Lisby, Marianne

2015-08-01

A risk stratification approach is needed to identify patients at high risk of medication errors and a resulting high need of medication review. The aim of this study was to perform risk stratification (distinguishing between low-risk, medium-risk and high-risk drugs) for drugs found to cause serious adverse reactions due to medication errors. The study employed a modified Delphi technique. Drugs from a systematic literature search were included into two rounds of a Delphi process. A panel of experts was asked to evaluate each identified drug's potential for harm and for clinically relevant drug-drug interactions on a scale from 1 (low risk) to 9 (high risk). A total of 36 experts were appointed to serve on the panel. Consensus was reached for 29/57 (51%) drugs or drug classes that cause harm, and for 32/57 (56%) of the drugs or drug classes that cause interactions. For the remaining drugs, a decision was made based on the median score. Two lists, one stating the drugs' potential for causing harm and the other stating clinically relevant drug-drug interactions, were stratified into low-risk, medium-risk and high-risk drugs. Based on a modified Delphi technique, we created two lists of drugs stratified into a low-risk, a medium-risk and a high-risk group of clinically relevant interactions or risk of harm to patients. The lists could be incorporated into a risk-scoring tool that stratifies the performance of medication reviews according to patients' risk of experiencing adverse reactions. none. not relevant.

Generalized scaling of seasonal thermal stratification in lakes

NASA Astrophysics Data System (ADS)

Shatwell, T.; Kirillin, G.

2016-12-01

The mixing regime is fundamental to the biogeochemisty and ecology of lakes because it determines the vertical transport of matter such as gases, nutrients, and organic material. Whereas shallow lakes are usually polymictic and regularly mix to the bottom, deep lakes tend to stratify seasonally, separating surface water from deep sediments and deep water from the atmosphere. Although empirical relationships exist to predict the mixing regime, a physically based, quantitative criterion is lacking. Here we review our recent research on thermal stratification in lakes at the transition between polymictic and stratified regimes. Using the mechanistic balance between potential and kinetic energy in terms of the Richardson number, we derive a generalized physical scaling for seasonal stratification in a closed lake basin. The scaling parameter is the critical mean basin depth that delineates polymictic and seasonally stratified lakes based on lake water transparency (Secchi depth), lake length, and an annual mean estimate for the Monin-Obukhov length. We validated the scaling on available data of 374 global lakes using logistic regression and found it to perform better than other criteria including a conventional open basin scaling or a simple depth threshold. The scaling has potential applications in estimating large scale greenhouse gas fluxes from lakes because the required inputs, like water transparency and basin morphology, can be acquired using the latest remote sensing technologies. The generalized scaling is universal for freshwater lakes and allows the seasonal mixing regime to be estimated without numerically solving the heat transport equations.

Postoperative Complications of Total Joint Arthroplasty in Obese Patients Stratified by BMI.

PubMed

Zusmanovich, Mikhail; Kester, Benjamin S; Schwarzkopf, Ran

2018-03-01

High body mass index (BMI) is associated with significant complications in patients undergoing total joint arthroplasty. Many studies have evaluated this trend, but few have looked at the rates of complications based on BMI as a continuous variable. The purpose of this study was to stratify obese patients into 3 BMI categories and evaluate their rates of complications and gauge whether transitioning from higher to lower BMI category lowers complication. Patients undergoing primary total joint arthroplasty were selected from the National Surgical Quality Improvement Program database from 2008-2015 and arranged into 3 groups based on BMI: O1 (BMI 30-34.9 kg/m 2 ), O2 (BMI 35-39.9 kg/m 2 ), and O3 (BMI >40 kg/m 2 ). Thirty-day complications were recorded and evaluated utilizing univariate and multivariate analyses stratified by BMI. A total of 268,663 patients were identified. Patients with a BMI >30 kg/m 2 had more infectious and medical complications compared with nonobese patients. Furthermore, there were increased complications as the BMI categories increased. Patients with a BMI >40 kg/m 2 (O3) had longer operating times, length of stay, higher rates of readmissions, reoperations, deep venous thrombosis, renal insufficiency, superficial infections, deep infections, and wound dehiscence. These trends were present when comparing the O2 with O1 category as well. We have demonstrated increased rates of medical and surgical complications in obese patients. Furthermore, we demonstrated a stepwise increase in complication rates when transitioning to higher BMI groups. Based on our data, we believe that preoperative counseling and interventions to decrease BMI should be explored before offering elective surgery to obese patients. Copyright © 2017 Elsevier Inc. All rights reserved.

Trace fossils from storm-influenced, oxygen-deficient outer shelf: lower Mississippian Price Formation of southern West Virginia

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

Bjerstedt, T.W.

The Price Formation in southern West Virginia was deposited dominantly in an oxygen-deficient, outer shelf environment along a siliciclastic profile from the basin plain to the alluvial plain. An overturned section at Bluefield, West Virginia, exposes the following lithofacies and environments in ascending order: laminated black silt-shales from the basin plain; a sand-rich submarine fan; outer shelf tempestites of hummocky, cross-stratified fine sandstone and completely bioturbated grayish-black, silt-shales; and shoreline sands in transition to thin, dirty coals of the coastal plain and Maccrady red beds of the alluvial plain. Trace fossils are abundant and are best preserved on the solesmore » of hummocky, cross-stratified sandstones. The Zoophycos ichnofacies occurs throughout 80 m of outer shelf deposits, which accumulated above storm wave base. The Zoophycos ichnofacies grades into the nearshore Skolithus ichnofacies with no apparent intervening Cruziana ichnofacies. Most ichnotaxa identified from the outer shelf are fodinichnia or pascichnia. Planar and helical Zoophycos, Helminthopsis, Helminthoida, Sclarituba (neonereites form), and Chondrites are characteristics. In most schemes, the Zoophycos ichnofacies occurs below storm wave base. At Bluefield, it has displaced the Cruziana ichnofacies above storm wave base due to the maintenance of a dysaerobic environment. The abundant organic matter preserved in a density-stratified water column was continually replenished during periods of upwelling. Conditions were extremely favorable for deposit feeders, but inhibiting to suspension feeders that were less tolerant of oxygen stress. The absence of distributary channel sands in the vertical sequence also indicates that offshore environments received no influx of oxygenated waters from the Price delta.« less

Uncertainty characterization approaches for risk assessment of DBPs in drinking water: a review.

PubMed

Chowdhury, Shakhawat; Champagne, Pascale; McLellan, P James

2009-04-01

The management of risk from disinfection by-products (DBPs) in drinking water has become a critical issue over the last three decades. The areas of concern for risk management studies include (i) human health risk from DBPs, (ii) disinfection performance, (iii) technical feasibility (maintenance, management and operation) of treatment and disinfection approaches, and (iv) cost. Human health risk assessment is typically considered to be the most important phase of the risk-based decision-making or risk management studies. The factors associated with health risk assessment and other attributes are generally prone to considerable uncertainty. Probabilistic and non-probabilistic approaches have both been employed to characterize uncertainties associated with risk assessment. The probabilistic approaches include sampling-based methods (typically Monte Carlo simulation and stratified sampling) and asymptotic (approximate) reliability analysis (first- and second-order reliability methods). Non-probabilistic approaches include interval analysis, fuzzy set theory and possibility theory. However, it is generally accepted that no single method is suitable for the entire spectrum of problems encountered in uncertainty analyses for risk assessment. Each method has its own set of advantages and limitations. In this paper, the feasibility and limitations of different uncertainty analysis approaches are outlined for risk management studies of drinking water supply systems. The findings assist in the selection of suitable approaches for uncertainty analysis in risk management studies associated with DBPs and human health risk.

Stratified at Seven: In-Class Ability Grouping and the Relative Age Effect

ERIC Educational Resources Information Center

Campbell, Tammy

2014-01-01

There is an established body of evidence indicating that a pupil's relative age within their school year cohort is associated with academic attainment throughout compulsory education. In England, autumn-born pupils consistently attain at higher levels than summer-born pupils. Analysis here investigates a possible channel of this relative age…

An Analysis of Job Satisfaction Among Public, College or University, and Special Librarians.

ERIC Educational Resources Information Center

Miniter, John J.

Usable data relating to six elements of job satisfaction: work, supervision, people, pay, promotion, and total satisfaction, were collected from 190 of a total sample of 310 librarians, chosen by stratified random sampling techniques from library association membership lists. The librarians, both male and female, represented three types of…

Trends in Antipsychotic Drug Use by Very Young, Privately Insured Children

ERIC Educational Resources Information Center

Olfson, Mark; Crystal, Stephen; Huang, Cecilia; Gerhard, Tobias

2010-01-01

Objective: This study describes recent trends and patterns in antipsychotic treatment of privately insured children aged 2 through 5 years. Method: A trend analysis is presented of antipsychotic medication use (1999-2001 versus 2007) stratified by patient characteristics. Data are analyzed from a large administrative database of privately insured…

Understanding the Priorities of Australian Secondary Schools through an Analysis of Their Mission and Vision Statements

ERIC Educational Resources Information Center

Allen, Kelly-Ann; Kern, Margaret L.; Vella-Brodrick, Dianne; Waters, Lea

2018-01-01

Purpose: The vision or mission statement of a school outlines the school's purpose and defines the context, goals, and aspirations that govern the institution. Using vision and mission statements, the present descriptive research study investigated trends in Australian secondary schools' priorities. Research Methods: A stratified sample of…

Computers in the Schools: How Will Educators Cope with the Revolution?

ERIC Educational Resources Information Center

Gleason, Gerald T.; Reed, Timothy

A study was implemented to conduct a long-range observation and analysis of the process by which computers are channeled into educational practice. Data collection involved a structured interview with knowledgeable representatives of 35 school districts in Wisconsin. Participating schools were selected randomly and stratified by size. Questions in…

Sensitivity of FIA Volume Estimates to Changes in Stratum Weights and Number of Strata

Treesearch

James A. Westfall; Michael Hoppus

2005-01-01

In the Northeast region, the USDA Forest Service Forest Inventory and Analysis (FIA) program utilizes stratified sampling techniques to improve the precision of population estimates. Recently, interpretation of aerial photographs was replaced with classified remotely sensed imagery to determine stratum weights and plot stratum assignments. However, stratum weights...

Information Needs of State Directors of Vocational Education.

ERIC Educational Resources Information Center

McCracken, J. David

To identify the critical problems of state directors of vocational education and the information sources utilized by them, data were collected by mail questionnaire and a series of telephone interviews with a stratified random sample of 15 state directors. Analysis of the data with respect to major problems, methods used to seek information,…

Reference List Accuracy in Social Work Journals: A Follow-Up Analysis

ERIC Educational Resources Information Center

Mitchell-Williams, Missy T.; Skipper, Antonius D.; Alexander, Marvin C.; Wilks, Scott E.

2017-01-01

Purpose: Following up an "Research on Social Work Practice" article published a decade ago, this study aimed to examine reference error rates among five, widely circulated social work journals. Methods: A stratified random sample of references was selected from the year 2013 (N = 500, 100/journal). Each was verified against the original…

Integrated Modeling and Analysis of Physical Oceanographic and Acoustic Processes

DTIC Science & Technology

2013-09-30

email: swinney@chaos.utexas.edu John Wilkin Department of Marine and Coastal Sciences, Rutgers University New Brunswick, NJ 08901-8521 phone...Doppler-shift field scattered by an object moving in a stratified medium, J. Acoust. Soc. Am., 113, 223-244, 2003. [11] Tang , D. J., J. N. Moum, J. F

Doing More with Less: A Preliminary Study of the School District Investment.

ERIC Educational Resources Information Center

MacPhail-Wilcox, Bettye

1983-01-01

Changes in cash management practices from 1978 to 1981 were investigated in a random sample of 145 North Carolina school districts, stratified by attendance size. Analysis using chi-square tests indicated the level of investment sophistication (as measured by the proportion of cash invested) has increased, especially for large districts. (RW)

GPX2 overexpression indicates poor prognosis in patients with hepatocellular carcinoma.

PubMed

Liu, Ting; Kan, Xue-Feng; Ma, Charlie; Chen, Li-Li; Cheng, Tian-Tian; Zou, Zhen-Wei; Li, Yong; Cao, Feng-Jun; Zhang, Wen-Jie; Yao, Jing; Li, Pin-Dong

2017-06-01

Glutathione peroxidase 2 has important role of tumor progression in lots of carcinomas, yet little is known about the prognosis of glutathione peroxidase 2 in hepatocellular carcinoma. Glutathione peroxidase 2 expression was assessed by immunohistochemistry in hepatocellular carcinoma tissues. The association between glutathione peroxidase 2 expression with clinicopathological/prognostic value was examined. Glutathione peroxidase 2 overexpression was correlated with alpha-fetoprotein level, larger tumor, BCLC stage, and tumor recurrence. Kaplan-Meier analysis showed that glutathione peroxidase 2 was an independent predictor for overall survival and time to recurrence. glutathione peroxidase 2 overexpression was correlated with poor prognosis in patient subgroups stratified by tumor size, differentiation, tumor-node-metastasis, and BCLC stage. Moreover, stratified analysis showed that tumor-node-metastasis stage-I patients with high glutathione peroxidase 2 expression had poor prognosis than those with low glutathione peroxidase 2 expression. Additionally, combination of glutathione peroxidase 2 and serum alpha-fetoprotein was correlated with prognosis in hepatocellular carcinoma. In conclusion, glutathione peroxidase 2 overexpression contributes to poor prognosis of hepatocellular carcinoma patients and helps to identify the high-risk hepatocellular carcinoma patients.

THERMAL NON-EQUILIBRIUM REVEALED BY PERIODIC PULSES OF RANDOM AMPLITUDES IN SOLAR CORONAL LOOPS

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

Auchère, F.; Froment, C.; Bocchialini, K.

2016-08-20

We recently detected variations in extreme ultraviolet intensity in coronal loops repeating with periods of several hours. Models of loops including stratified and quasi-steady heating predict the development of a state of thermal non-equilibrium (TNE): cycles of evaporative upflows at the footpoints followed by falling condensations at the apex. Based on Fourier and wavelet analysis, we demonstrate that the observed periodic signals are indeed not signatures of vibrational modes. Instead, superimposed on the power law expected from the stochastic background emission, the power spectra of the time series exhibit the discrete harmonics and continua expected from periodic trains of pulsesmore » of random amplitudes. These characteristics reinforce our earlier interpretation of these pulsations as being aborted TNE cycles.« less

Field strategies for the calibration and validation of high-resolution forest carbon maps: Scaling from plots to a three state region MD, DE, & PA, USA.

NASA Astrophysics Data System (ADS)

Dolan, K. A.; Huang, W.; Johnson, K. D.; Birdsey, R.; Finley, A. O.; Dubayah, R.; Hurtt, G. C.

2016-12-01

In 2010 Congress directed NASA to initiate research towards the development of Carbon Monitoring Systems (CMS). In response, our team has worked to develop a robust, replicable framework to quantify and map aboveground forest biomass at high spatial resolutions. Crucial to this framework has been the collection of field-based estimates of aboveground tree biomass, combined with remotely detected canopy and structural attributes, for calibration and validation. Here we evaluate the field- based calibration and validation strategies within this carbon monitoring framework and discuss the implications on local to national monitoring systems. Through project development, the domain of this research has expanded from two counties in MD (2,181 km2), to the entire state of MD (32,133 km2), and most recently the tri-state region of MD, PA, and DE (157,868 km2) and covers forests in four major USDA ecological providences. While there are approximately 1000 Forest Inventory and Analysis (FIA) plots distributed across the state of MD, 60% fell in areas considered non-forest or had conditions that precluded them from being measured in the last forest inventory. Across the two pilot counties, where population and landuse competition is high, that proportion rose to 70% Thus, during the initial phases of this project 850 independent field plots were established for model calibration following a random stratified design to insure the adequate representation of height and vegetation classes found across the state, while FIA data were used as an independent data source for validation. As the project expanded to cover the larger spatial tri-state domain, the strategy was flipped to base calibration on more than 3,300 measured FIA plots, as they provide a standardized, consistent and available data source across the nation. An additional 350 stratified random plots were deployed in the Northern Mixed forests of PA and the Coastal Plains forests of DE for validation.

Characterizing the performance of an affordable, multichannel conductivity probe for density measurements in stratified flows

NASA Astrophysics Data System (ADS)

Subramanian, Balaji; Carminati, Marco; Luzzatto-Fegiz, Paolo

2017-11-01

In stratified flows, conductivity (combined with temperature) is often used to measure density. The conductivity probes typically used can resolve very fine spatial scales, but on the downside they are fragile, expensive, sensitive to environmental noise and have only single channel capability. Recently a low-cost, robust, arduino-based probe called Conduino was developed, which can be valuable in a wide range of applications where resolving extremely small spatial scales is not needed. This probe uses micro-USB connectors as actual conductivity sensors with a custom designed electronic board for simultaneous acquisition from multiple probes, with conductivity resolution comparable to commercially available PME conductivity probe. A detailed assessment of performance of this Conduino probe is described here. To establish time response and sensitivity as a function of electrode geometry, we build a variety of shapes for different kinds of applications, with tip spacing ranging from 0.5-2.5 mm, and with electrode length ranging from 2.3-6 mm. We set up a two-layer density profile and traverse it rapidly, yielding a time response comparable to PME. The Conduino's multi-channel capability is used to operate probe arrays, which helps to construct density fields in stratified flows.

Robust computation of dipole electromagnetic fields in arbitrarily anisotropic, planar-stratified environments.

PubMed

Sainath, Kamalesh; Teixeira, Fernando L; Donderici, Burkay

2014-01-01

We develop a general-purpose formulation, based on two-dimensional spectral integrals, for computing electromagnetic fields produced by arbitrarily oriented dipoles in planar-stratified environments, where each layer may exhibit arbitrary and independent anisotropy in both its (complex) permittivity and permeability tensors. Among the salient features of our formulation are (i) computation of eigenmodes (characteristic plane waves) supported in arbitrarily anisotropic media in a numerically robust fashion, (ii) implementation of an hp-adaptive refinement for the numerical integration to evaluate the radiation and weakly evanescent spectra contributions, and (iii) development of an adaptive extension of an integral convergence acceleration technique to compute the strongly evanescent spectrum contribution. While other semianalytic techniques exist to solve this problem, none have full applicability to media exhibiting arbitrary double anisotropies in each layer, where one must account for the whole range of possible phenomena (e.g., mode coupling at interfaces and nonreciprocal mode propagation). Brute-force numerical methods can tackle this problem but only at a much higher computational cost. The present formulation provides an efficient and robust technique for field computation in arbitrary planar-stratified environments. We demonstrate the formulation for a number of problems related to geophysical exploration.

Detectable end of radiation prostate specific antigen assists in identifying men with unfavorable intermediate-risk prostate cancer at high risk of distant recurrence and cancer-specific mortality.

PubMed

Hayman, Jonathan; Phillips, Ryan; Chen, Di; Perin, Jamie; Narang, Amol K; Trieu, Janson; Radwan, Noura; Greco, Stephen; Deville, Curtiland; McNutt, Todd; Song, Daniel Y; DeWeese, Theodore L; Tran, Phuoc T

2018-06-01

Undetectable End of Radiation PSA (EOR-PSA) has been shown to predict improved survival in prostate cancer (PCa). While validating the unfavorable intermediate-risk (UIR) and favorable intermediate-risk (FIR) stratifications among Johns Hopkins PCa patients treated with radiotherapy, we examined whether EOR-PSA could further risk stratify UIR men for survival. A total of 302 IR patients were identified in the Johns Hopkins PCa database (178 UIR, 124 FIR). Kaplan-Meier curves and multivariable analysis was performed via Cox regression for biochemical recurrence free survival (bRFS), distant metastasis free survival (DMFS), and overall survival (OS), while a competing risks model was used for PCa specific survival (PCSS). Among the 235 patients with known EOR-PSA values, we then stratified by EOR-PSA and performed the aforementioned analysis. The median follow-up time was 11.5 years (138 months). UIR was predictive of worse DMFS and PCSS (P = 0.008 and P = 0.023) on multivariable analysis (MVA). Increased radiation dose was significant for improved DMFS (P = 0.016) on MVA. EOR-PSA was excluded from the models because it did not trend towards significance as a continuous or binary variable due to interaction with UIR, and we were unable to converge a multivariable model with a variable to control for this interaction. However, when stratifying by detectable versus undetectable EOR-PSA, UIR had worse DMFS and PCSS among detectable EOR-PSA patients, but not undetectable patients. UIR was significant on MVA among detectable EOR-PSA patients for DMFS (P = 0.021) and PCSS (P = 0.033), while RT dose also predicted PCSS (P = 0.013). EOR-PSA can assist in predicting DMFS and PCSS among UIR patients, suggesting a clinically meaningful time point for considering intensification of treatment in clinical trials of intermediate-risk men. © 2018 Wiley Periodicals, Inc.

Association of vitamin D receptor BsmI, TaqI, FokI, and ApaI polymorphisms with susceptibility of chronic periodontitis: A systematic review and meta-analysis based on 38 case -control studies.

PubMed

Mashhadiabbas, Fatemeh; Neamatzadeh, Hossein; Nasiri, Rezvan; Foroughi, Elnaz; Farahnak, Soudabeh; Piroozmand, Parisa; Mazaheri, Mahta; Zare-Shehneh, Masoud

2018-01-01

There has been increasing interest in the study of the association between Vitamin D receptor (VDR) gene polymorphisms and risk of chronic periodontitis. However, the results remain inconclusive. To better understand the roles of VDR polymorphisms (BsmI, TaqI, FokI, and ApaI) in chronic periodontitis susceptibility, we conducted this systematic review and meta-analysis. The PubMed, Google Scholar, and Web of Science database were systemically searched to determine all the eligible studies about VDR polymorphisms and risk of chronic periodontitis up to April 2017. Odds ratio (OR) and 95% confidence interval (CI) were used to evaluate the associations between VDR polymorphisms and chronic periodontitis risk. All the statistical analyses were performed by Comprehensive Meta-Analysis. All P values were two-tailed with a significant level at 0.05. Finally, a total of 38 case-control studies in 19 publications were identified which met our inclusion criteria. There are ten studies with 866 chronic periodontitis cases and 786 controls for BsmI, 16 studies with 1570 chronic periodontitis cases and 1676 controls for TaqI, five studies with 374 chronic periodontitis cases and 382 controls for FokI, and seven studies with 632 chronic periodontitis cases and 604 controls for ApaI. Overall, no significant association was observed between VDR gene BsmI, TaqI, FokI, and ApaI polymorphisms and risk of chronic periodontitis in any genetic model. Subgroup analysis stratified by ethnicity suggested a significant association between BsmI polymorphism and chronic periodontitis risk in the Caucasian subgroup under allele model (A vs. G: OR = 1.747, 95% CI = 1.099-2.778, P = 0.018). Further, no significant associations were observed when stratified by Hardy-Weinberg equilibrium status for BsmI, TaqI, and ApaI. Our results suggest that BsmI, TaqI, FokI, and ApaI polymorphisms in the VDR gene might not be associated with risk of chronic periodontitis in overall population.

Association of vitamin D receptor BsmI, TaqI, FokI, and ApaI polymorphisms with susceptibility of chronic periodontitis: A systematic review and meta-analysis based on 38 case –control studies

PubMed Central

Mashhadiabbas, Fatemeh; Neamatzadeh, Hossein; Nasiri, Rezvan; Foroughi, Elnaz; Farahnak, Soudabeh; Piroozmand, Parisa; Mazaheri, Mahta; Zare-Shehneh, Masoud

2018-01-01

Background: There has been increasing interest in the study of the association between Vitamin D receptor (VDR) gene polymorphisms and risk of chronic periodontitis. However, the results remain inconclusive. To better understand the roles of VDR polymorphisms (BsmI, TaqI, FokI, and ApaI) in chronic periodontitis susceptibility, we conducted this systematic review and meta-analysis. Materials and Methods: The PubMed, Google Scholar, and Web of Science database were systemically searched to determine all the eligible studies about VDR polymorphisms and risk of chronic periodontitis up to April 2017. Odds ratio (OR) and 95% confidence interval (CI) were used to evaluate the associations between VDR polymorphisms and chronic periodontitis risk. All the statistical analyses were performed by Comprehensive Meta-Analysis. All P values were two-tailed with a significant level at 0.05. Results: Finally, a total of 38 case–control studies in 19 publications were identified which met our inclusion criteria. There are ten studies with 866 chronic periodontitis cases and 786 controls for BsmI, 16 studies with 1570 chronic periodontitis cases and 1676 controls for TaqI, five studies with 374 chronic periodontitis cases and 382 controls for FokI, and seven studies with 632 chronic periodontitis cases and 604 controls for ApaI. Overall, no significant association was observed between VDR gene BsmI, TaqI, FokI, and ApaI polymorphisms and risk of chronic periodontitis in any genetic model. Subgroup analysis stratified by ethnicity suggested a significant association between BsmI polymorphism and chronic periodontitis risk in the Caucasian subgroup under allele model (A vs. G: OR = 1.747, 95% CI = 1.099–2.778, P = 0.018). Further, no significant associations were observed when stratified by Hardy–Weinberg equilibrium status for BsmI, TaqI, and ApaI. Conclusion: Our results suggest that BsmI, TaqI, FokI, and ApaI polymorphisms in the VDR gene might not be associated with risk of chronic periodontitis in overall population. PMID:29922333

A prognostic classifier for patients with colorectal cancer liver metastasis, based on AURKA, PTGS2 and MMP9.

PubMed

Goos, Jeroen A C M; Coupé, Veerle M H; van de Wiel, Mark A; Diosdado, Begoña; Delis-Van Diemen, Pien M; Hiemstra, Annemieke C; de Cuba, Erienne M V; Beliën, Jeroen A M; Menke-van der Houven van Oordt, C Willemien; Geldof, Albert A; Meijer, Gerrit A; Hoekstra, Otto S; Fijneman, Remond J A

2016-01-12

Prognosis of patients with colorectal cancer liver metastasis (CRCLM) is estimated based on clinicopathological models. Stratifying patients based on tumor biology may have additional value. Tissue micro-arrays (TMAs), containing resected CRCLM and corresponding primary tumors from a multi-institutional cohort of 507 patients, were immunohistochemically stained for 18 candidate biomarkers. Cross-validated hazard rate ratios (HRRs) for overall survival (OS) and the proportion of HRRs with opposite effect (P(HRR < 1) or P(HRR > 1)) were calculated. A classifier was constructed by classification and regression tree (CART) analysis and its prognostic value determined by permutation analysis. Correlations between protein expression in primary tumor-CRCLM pairs were calculated. Based on their putative prognostic value, EGFR (P(HRR < 1) = .02), AURKA (P(HRR < 1) = .02), VEGFA (P(HRR < 1) = .02), PTGS2 (P(HRR < 1) = .01), SLC2A1 (P(HRR > 1) < 01), HIF1α (P(HRR > 1) = .06), KCNQ1 (P(HRR > 1) = .09), CEA (P (HRR > 1) = .05) and MMP9 (P(HRR < 1) = .07) were included in the CART analysis (n = 201). The resulting classifier was based on AURKA, PTGS2 and MMP9 expression and was associated with OS (HRR 2.79, p < .001), also after multivariate analysis (HRR 3.57, p < .001). The prognostic value of the biomarker-based classifier was superior to the clinicopathological model (p = .001). Prognostic value was highest for colon cancer patients (HRR 5.71, p < .001) and patients not treated with systemic therapy (HRR 3.48, p < .01). Classification based on protein expression in primary tumors could be based on AURKA expression only (HRR 2.59, p = .04). A classifier was generated for patients with CRCLM with improved prognostic value compared to the standard clinicopathological prognostic parameters, which may aid selection of patients who may benefit from adjuvant systemic therapy.

In-hospital fall-risk screening in 4,735 geriatric patients from the LUCAS project.

PubMed

Neumann, L; Hoffmann, V S; Golgert, S; Hasford, J; Von Renteln-Kruse, W

2013-03-01

In-hospital falls in older patients are frequent, but the identification of patients at risk of falling is challenging. Aim of this study was to improve the identification of high-risk patients. Therefore, a simplified screening-tool was developed, validated, and compared to the STRATIFY predictive accuracy. Retrospective analysis of 4,735 patients; evaluation of predictive accuracy of STRATIFY and its single risk factors, as well as age, gender and psychotropic medication; splitting the dataset into a learning and a validation sample for modelling fall-risk screening and independent, temporal validation. Geriatric clinic at an academic teaching hospital in Hamburg, Germany. 4,735 hospitalised patients ≥65 years. Sensitivity, specificity, positive and negative predictive value, Odds Ratios, Youden-Index and the rates of falls and fallers were calculated. There were 10.7% fallers, and the fall rate was 7.9/1,000 hospital days. In the learning sample, mental alteration (OR 2.9), fall history (OR 2.1), and insecure mobility (Barthel-Index items 'transfer' + 'walking' score = 5, 10 or 15) (OR 2.3) had the most strongest association to falls. The LUCAS Fall-Risk Screening uses these risk factors, and patients with ≥2 risk factors contributed to the high-risk group (30.9%). In the validation sample, STRATIFY SENS was 56.8, SPEC 59.6, PPV 13.5 and NPV 92.6 vs. LUCAS Fall-Risk Screening was SENS 46.0, SPEC 71.1, PPV 14.9 and NPV 92.3. Both the STRATIFY and the LUCAS Fall-Risk Screening showed comparable results in defining a high-risk group. Impaired mobility and cognitive status were closely associated to falls. The results do underscore the importance of functional status as essential fall-risk factor in older hospitalised patients.

A pretest prognostic score to assess patients undergoing exercise or pharmacological stress testing

PubMed Central

Morise, Anthony; Evans, Matthew; Jalisi, Farrukh; Shetty, Rajendra; Stauffer, Marc

2007-01-01

Objective A previously developed pretest score was validated to stratify patients presenting for exercise testing with suspected coronary disease according to the presence of angiographic coronary disease. Our goal was to determine how well this pretest score risk stratified patients undergoing pharmacological and exercise stress tests concerning prognostic endpoints. Design Retrospective cohort analysis. Setting University hospital stress laboratory. Patients 7452 unselected ambulatory patients with symptoms of suspected coronary disease undergoing stress testing between 1995 and 2004. Main outcomes measures All‐cause death, cardiac death and non‐fatal myocardial infarction. Results The rate of all‐cause death was 5.5% (CI 5.0 to 6.1) with 4.3 (SD 2.4) years of follow‐up (Exercise 2.8% (CI 2.3 to 3.2) v Pharmacological group 11.9% (CI 10.5 to 13.3); p<0.001). The rate of cardiac death/myocardial infarction was 2.6% (CI 2.2 to 3.0) (Exercise 1.4% (CI 1.1 to 1.8) v Pharmacological group 5.3% (CI 4.3 to 6.2); p<0.001). In both groups, stratification by pretest score was significant for all‐cause death and the combined endpoint. However, stratification was more effective in the pharmacological group using the combined endpoint rather than all‐cause death. Pharmacological stress patients in intermediate and high risk groups were at higher risk than their respective exercise test cohorts. Referral for pharmacological stress testing was found to be an independent predictor of time to death (2.7 (CI 2.0 to 3.6); p<0.001). Conclusion A pretest score previously validated to stratify according to angiographic outcomes, effectively risk stratified pharmacological and exercise stress patients according to the combined endpoint of cardiac death/myocardial infarction. PMID:17228070

A pretest prognostic score to assess patients undergoing exercise or pharmacological stress testing.

PubMed

Morise, Anthony; Evans, Matthew; Jalisi, Farrukh; Shetty, Rajendra; Stauffer, Marc

2007-02-01

A previously developed pretest score was validated to stratify patients presenting for exercise testing with suspected coronary disease according to the presence of angiographic coronary disease. Our goal was to determine how well this pretest score risk stratified patients undergoing pharmacological and exercise stress tests concerning prognostic endpoints. Retrospective cohort analysis. University hospital stress laboratory. 7452 unselected ambulatory patients with symptoms of suspected coronary disease undergoing stress testing between 1995 and 2004. All-cause death, cardiac death and non-fatal myocardial infarction. The rate of all-cause death was 5.5% (CI 5.0 to 6.1) with 4.3 (SD 2.4) years of follow-up (Exercise 2.8% (CI 2.3 to 3.2) v Pharmacological group 11.9% (CI 10.5 to 13.3); p<0.001). The rate of cardiac death/myocardial infarction was 2.6% (CI 2.2 to 3.0) (Exercise 1.4% (CI 1.1 to 1.8) v Pharmacological group 5.3% (CI 4.3 to 6.2); p<0.001). In both groups, stratification by pretest score was significant for all-cause death and the combined endpoint. However, stratification was more effective in the pharmacological group using the combined endpoint rather than all-cause death. Pharmacological stress patients in intermediate and high risk groups were at higher risk than their respective exercise test cohorts. Referral for pharmacological stress testing was found to be an independent predictor of time to death (2.7 (CI 2.0 to 3.6); p<0.001). A pretest score previously validated to stratify according to angiographic outcomes, effectively risk stratified pharmacological and exercise stress patients according to the combined endpoint of cardiac death/myocardial infarction.

DSM-5 field trials in the United States and Canada, Part I: study design, sampling strategy, implementation, and analytic approaches.

PubMed

Clarke, Diana E; Narrow, William E; Regier, Darrel A; Kuramoto, S Janet; Kupfer, David J; Kuhl, Emily A; Greiner, Lisa; Kraemer, Helena C

2013-01-01

This article discusses the design,sampling strategy, implementation,and data analytic processes of the DSM-5 Field Trials. The DSM-5 Field Trials were conducted by using a test-retest reliability design with a stratified sampling approach across six adult and four pediatric sites in the United States and one adult site in Canada. A stratified random sampling approach was used to enhance precision in the estimation of the reliability coefficients. A web-based research electronic data capture system was used for simultaneous data collection from patients and clinicians across sites and for centralized data management.Weighted descriptive analyses, intraclass kappa and intraclass correlation coefficients for stratified samples, and receiver operating curves were computed. The DSM-5 Field Trials capitalized on advances since DSM-III and DSM-IV in statistical measures of reliability (i.e., intraclass kappa for stratified samples) and other recently developed measures to determine confidence intervals around kappa estimates. Diagnostic interviews using DSM-5 criteria were conducted by 279 clinicians of varied disciplines who received training comparable to what would be available to any clinician after publication of DSM-5.Overall, 2,246 patients with various diagnoses and levels of comorbidity were enrolled,of which over 86% were seen for two diagnostic interviews. A range of reliability coefficients were observed for the categorical diagnoses and dimensional measures. Multisite field trials and training comparable to what would be available to any clinician after publication of DSM-5 provided “real-world” testing of DSM-5 proposed diagnoses.

Diffusion of breast conserving surgery in medical communities.

PubMed

Jerome-D'Emilia, Bonnie; Begun, James W

2005-01-01

Excluding skin cancers, breast cancer is the most common form of cancer in women. Due to an increased focus on early detection, many more cases of breast cancer are now diagnosed at an early stage, which makes the use of breast conserving surgery (BCS) an efficacious and often more desirable treatment choice than mastectomy. An analysis of the variation in the use of BCS in the United States was performed using data from the years 1988 and 1994, and stratifying hospitals on the basis of teaching status. In both 1988 and 1994, BCS was highest in academic teaching hospitals and lowest in community hospitals. This finding is interpreted within the framework of classical diffusion theory. Social and cultural norms in local medical communities have a strong effect on the degree to which innovations diffuse rapidly or not. This analysis is useful in the understanding of geographic and hospital-based variations in treatment for early stage breast cancer and other illnesses that have long and strongly held traditions of treatment.

Gender differences and age-related changes in body fat mass in Tibetan children and teenagers: an analysis by the bioelectrical impedance method.

PubMed

Zhang, Hai-Long; Fu, Qiang; Li, Wen-Hui; Liu, Su-Wei; Zhong, Hua; Duoji, Bai-Ma; Zhang, Mei-Zhi; Lv, Po; Xi, Huan-Jiu

2015-01-01

We aimed to obtain the fat base value and the fat distribution characteristics of Tibetan children and teenagers by estimating their body fat content with the bioelectrical impedance method. We recruited 1427 healthy children and teenagers by a stratified cluster sampling method. By using bioelectrical impedance analysis, we obtained various values relevant to fat. We found that total body fat mass and the fat mass of various body parts increased with age in boys and girls. Yet there were no differences between age groups until 11 years. However, fat mass increased quickly between 11 and 18 years, and significant differences were seen between adolescent boys and girls; all fat indices were higher in girls than in boys (p<0.05). The characteristics of fat in Tibetan children and teenagers in Tibet is related to age and gender related hormone secretion, which reflects the physiological characteristics in different developmental stages.

Phenotypes of organ involvement in sarcoidosis.

PubMed

Schupp, Jonas Christian; Freitag-Wolf, Sandra; Bargagli, Elena; Mihailović-Vučinić, Violeta; Rottoli, Paola; Grubanovic, Aleksandar; Müller, Annegret; Jochens, Arne; Tittmann, Lukas; Schnerch, Jasmin; Olivieri, Carmela; Fischer, Annegret; Jovanovic, Dragana; Filipovic, Snežana; Videnovic-Ivanovic, Jelica; Bresser, Paul; Jonkers, René; O'Reilly, Kate; Ho, Ling-Pei; Gaede, Karoline I; Zabel, Peter; Dubaniewicz, Anna; Marshall, Ben; Kieszko, Robert; Milanowski, Janusz; Günther, Andreas; Weihrich, Anette; Petrek, Martin; Kolek, Vitezslav; Keane, Michael P; O'Beirne, Sarah; Donnelly, Seamas; Haraldsdottir, Sigridur Olina; Jorundsdottir, Kristin B; Costabel, Ulrich; Bonella, Francesco; Wallaert, Benoît; Grah, Christian; Peroš-Golubičić, Tatjana; Luisetti, Mauritio; Kadija, Zamir; Pabst, Stefan; Grohé, Christian; Strausz, János; Vašáková, Martina; Sterclova, Martina; Millar, Ann; Homolka, Jiří; Slováková, Alena; Kendrick, Yvonne; Crawshaw, Anjali; Wuyts, Wim; Spencer, Lisa; Pfeifer, Michael; Valeyre, Dominique; Poletti, Venerino; Wirtz, Hubertus; Prasse, Antje; Schreiber, Stefan; Krawczak, Michael; Müller-Quernheim, Joachim

2018-01-01

Sarcoidosis is a highly variable, systemic granulomatous disease of hitherto unknown aetiology. The GenPhenReSa (Genotype-Phenotype Relationship in Sarcoidosis) project represents a European multicentre study to investigate the influence of genotype on disease phenotypes in sarcoidosis.The baseline phenotype module of GenPhenReSa comprised 2163 Caucasian patients with sarcoidosis who were phenotyped at 31 study centres according to a standardised protocol.From this module, we found that patients with acute onset were mainly female, young and of Scadding type I or II. Female patients showed a significantly higher frequency of eye and skin involvement, and complained more of fatigue. Based on multidimensional correspondence analysis and subsequent cluster analysis, patients could be clearly stratified into five distinct, yet undescribed, subgroups according to predominant organ involvement: 1) abdominal organ involvement, 2) ocular-cardiac-cutaneous-central nervous system disease involvement, 3) musculoskeletal-cutaneous involvement, 4) pulmonary and intrathoracic lymph node involvement, and 5) extrapulmonary involvement.These five new clinical phenotypes will be useful to recruit homogenous cohorts in future biomedical studies. Copyright ©ERS 2018.

Sampling design for an integrated socioeconomic and ecological survey by using satellite remote sensing and ordination

PubMed Central

Binford, Michael W.; Lee, Tae Jeong; Townsend, Robert M.

2004-01-01

Environmental variability is an important risk factor in rural agricultural communities. Testing models requires empirical sampling that generates data that are representative in both economic and ecological domains. Detrended correspondence analysis of satellite remote sensing data were used to design an effective low-cost sampling protocol for a field study to create an integrated socioeconomic and ecological database when no prior information on ecology of the survey area existed. We stratified the sample for the selection of tambons from various preselected provinces in Thailand based on factor analysis of spectral land-cover classes derived from satellite data. We conducted the survey for the sampled villages in the chosen tambons. The resulting data capture interesting variations in soil productivity and in the timing of good and bad years, which a purely random sample would likely have missed. Thus, this database will allow tests of hypotheses concerning the effect of credit on productivity, the sharing of idiosyncratic risks, and the economic influence of environmental variability. PMID:15254298

ARIANNA: A research environment for neuroimaging studies in autism spectrum disorders.

PubMed

Retico, Alessandra; Arezzini, Silvia; Bosco, Paolo; Calderoni, Sara; Ciampa, Alberto; Coscetti, Simone; Cuomo, Stefano; De Santis, Luca; Fabiani, Dario; Fantacci, Maria Evelina; Giuliano, Alessia; Mazzoni, Enrico; Mercatali, Pietro; Miscali, Giovanni; Pardini, Massimiliano; Prosperi, Margherita; Romano, Francesco; Tamburini, Elena; Tosetti, Michela; Muratori, Filippo

2017-08-01

The complexity and heterogeneity of Autism Spectrum Disorders (ASD) require the implementation of dedicated analysis techniques to obtain the maximum from the interrelationship among many variables that describe affected individuals, spanning from clinical phenotypic characterization and genetic profile to structural and functional brain images. The ARIANNA project has developed a collaborative interdisciplinary research environment that is easily accessible to the community of researchers working on ASD (https://arianna.pi.infn.it). The main goals of the project are: to analyze neuroimaging data acquired in multiple sites with multivariate approaches based on machine learning; to detect structural and functional brain characteristics that allow the distinguishing of individuals with ASD from control subjects; to identify neuroimaging-based criteria to stratify the population with ASD to support the future development of personalized treatments. Secure data handling and storage are guaranteed within the project, as well as the access to fast grid/cloud-based computational resources. This paper outlines the web-based architecture, the computing infrastructure and the collaborative analysis workflows at the basis of the ARIANNA interdisciplinary working environment. It also demonstrates the full functionality of the research platform. The availability of this innovative working environment for analyzing clinical and neuroimaging information of individuals with ASD is expected to support researchers in disentangling complex data thus facilitating their interpretation. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Impact of Behavioral Health Issues on Soldiers Returning from Deployment -- Assessing the Programs for Reintegration of South Carolina National Guard Soldiers

DTIC Science & Technology

2011-05-23

determine if the group means are significantly different. Analysis should include comparison of pretest - posttest means within- group and between... groups . A repeated measures analysis should also be conducted on subject‘s pretest - posttest means within groups . Information gained from the statistical...Black Single Unemployed 30 - 39 Senior NCO Hispanic ≥ 40 Officers Other - A research design embedding a pretest / posttest with a stratified then

Torsional Oscillations in a Global Solar Dynamo

NASA Astrophysics Data System (ADS)

Beaudoin, P.; Charbonneau, P.; Racine, E.; Smolarkiewicz, P. K.

2013-02-01

We characterize and analyze rotational torsional oscillations developing in a large-eddy magnetohydrodynamical simulation of solar convection (Ghizaru, Charbonneau, and Smolarkiewicz, Astrophys. J. Lett. 715, L133, 2010; Racine et al., Astrophys. J. 735, 46, 2011) producing an axisymmetric, large-scale, magnetic field undergoing periodic polarity reversals. Motivated by the many solar-like features exhibited by these oscillations, we carry out an analysis of the large-scale zonal dynamics. We demonstrate that simulated torsional oscillations are not driven primarily by the periodically varying large-scale magnetic torque, as one might have expected, but rather via the magnetic modulation of angular-momentum transport by the large-scale meridional flow. This result is confirmed by a straightforward energy analysis. We also detect a fairly sharp transition in rotational dynamics taking place as one moves from the base of the convecting layers to the base of the thin tachocline-like shear layer formed in the stably stratified fluid layers immediately below. We conclude by discussing the implications of our analyses with regard to the mechanism of amplitude saturation in the global dynamo operating in the simulation, and speculate on the possible precursor value of torsional oscillations for the forecast of solar-cycle characteristics.

Accelerometry-based gait analysis, an additional objective approach to screen subjects at risk for falling.

PubMed

Senden, R; Savelberg, H H C M; Grimm, B; Heyligers, I C; Meijer, K

2012-06-01

This study investigated whether the Tinetti scale, as a subjective measure for fall risk, is associated with objectively measured gait characteristics. It is studied whether gait parameters are different for groups that are stratified for fall risk using the Tinetti scale. Moreover, the discriminative power of gait parameters to classify elderly according to the Tinetti scale is investigated. Gait of 50 elderly with a Tinneti>24 and 50 elderly with a Tinetti≤24 was analyzed using acceleration-based gait analysis. Validated algorithms were used to derive spatio-temporal gait parameters, harmonic ratio, inter-stride amplitude variability and root mean square (RMS) from the accelerometer data. Clear differences in gait were found between the groups. All gait parameters correlated with the Tinetti scale (r-range: 0.20-0.73). Only walking speed, step length and RMS showed moderate to strong correlations and high discriminative power to classify elderly according to the Tinetti scale. It is concluded that subtle gait changes that have previously been related to fall risk are not captured by the subjective assessment. It is therefore worthwhile to include objective gait assessment in fall risk screening. Copyright © 2012 Elsevier B.V. All rights reserved.

Genetic structure of the populations migrating from San Luis Potosi and Zacatecas to Nuevo León in Mexico.

PubMed

Cerda-Flores, R M; Kshatriya, G K; Barton, S A; Leal-Garza, C H; Garza-Chapa, R; Schull, W J; Chakraborty, R

1991-06-01

The Mexicans residing in the Monterrey metropolitan area in Nuevo León, Mexico, were grouped by generation and birthplace [Monterrey Metropolitan Area (MMA), San Luis Potosi (SLP), and Zacatecas (ZAC)] of the four grandparents to determine the extent of genetic variation within this population and the genetic differences, if any, between the natives living in the MMA and the immigrant populations from SLP and ZAC. Nine genetic marker systems were analyzed. The genetic distance analysis indicates that SLP and ZAC are similar to the MMA, irrespective of birthplace and generation. Gene diversity analysis (GST) suggests that more than 96% of the total gene diversity (HT) can be attributed to individual variation within the population. The genetic admixture analysis suggests that the Mexicans of the MMA, SLP, and ZAC, stratified by birthplace and generation, have received a predominantly Spanish contribution (78.5%), followed by a Mexican Indian contribution (21.5%). Similarly, admixture analysis, conducted on the population of Nuevo León and stratified by generation, indicates a substantial contribution from the MMA (64.6%), followed by ZAC (22.1%) and SLP (13.3%). Finally, we demonstrate that there is no nonrandom association of alleles among the genetic marker systems (i.e., no evidence of gametic disequilibrium) despite the Mestizo origin of this population.

Results of complex aortic stent grafting of abdominal aortic aneurysms stratified according to the proximal landing zone using the Society for Vascular Surgery classification.

PubMed

Patel, Sanjay D; Constantinou, Jason; Simring, Dominic; Ramirez, Manfred; Agu, Obiekezie; Hamilton, Hamish; Ivancev, Krassi

2015-08-01

Advances in endovascular technology have led to the successful treatment of complex abdominal aortic aneurysms. However, there is currently no consensus on what constitutes a juxtarenal, pararenal, or suprarenal aneurysm. There is emerging evidence that the extent of the aneurysm repair is associated with outcome. We compare the outcomes of 150 consecutive patients treated with a fenestrated or branched stent graft and present the data stratified according to the Society for Vascular Surgery classification based on proximal anatomic landing zones. A prospectively collected database of consecutive patients undergoing fenestrated or branched stent graft insertion in a tertiary center between 2008 and 2013 was retrospectively analyzed. Aneurysms were subdivided into zones according to where the area of proximal seal could be achieved in relation to the visceral arteries. Zone 8 covers the renal arteries, zone 7 covers the superior mesenteric artery, and zone 6 covers the celiac axis. Patient demographics, operative variables, mortality, and major morbidity were analyzed by univariate and multivariate analysis to assess for differences between zones. During the study period, 150 patients were treated. There were 49 in zone 8, 76 in zone 7, and 25 in zone 6. Prior aortic surgery had been performed in 19 patients, which included 11 patients with previous endovascular aneurysm repairs. There was significantly increased blood loss (P < .001), operative time (P < .0001), total hospital stay (P = .018), and intensive care unit stay (P < .0001) as the zones ascended the aorta. There were 14 inpatient deaths recorded across all zones with a 30-day mortality rate of 8%. Logistic regression analysis for 30 day mortality showed a significant increase as the zones ascended (P = .007). Kaplan-Meier analysis showed that 5-year survival significantly deteriorated as the zones ascended (P = .039), with no significant difference in the freedom from reintervention curves between zones (P = .37). We have shown that the extent of the aneurysm repair as determined by the proximal sealing zone is associated with outcome. Mortality, operative duration, blood loss, and hospital stay all significantly increased as the zones ascended. These data also validate the use of the proposed new classification based on aortic anatomy. Copyright © 2015 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Prevalence of antepartum hemorrhage in women with placenta previa: a systematic review and meta-analysis

PubMed Central

Fan, Dazhi; Wu, Song; Liu, Li; Xia, Qing; Wang, Wen; Guo, Xiaoling; Liu, Zhengping

2017-01-01

Antepartum hemorrhage (APH) is an important cause of perinatal mortality and maternal morbidity in pregnant women with placenta previa in the world. However, the epidemiological characteristics are not completely understood. We performed an initial systematic review and meta-analysis to assess the prevalence of APH in pregnant women with placenta previa. It was totally performed following the Preferred Reporting Items for Systematic reviews and Meta-Analysis statement. PubMed, Elsevier Science Direct, and the Cochrane Library were searched before April 2016. A meta-analysis with a random-effects model based on a proportions approach was performed to determine the prevalence. Stratified analyses, meta-regression method, and sensitivity analysis were utilized to analyze the heterogeneity. A total of 29 articles were included. The pooled overall prevalence of APH among pregnant women with placenta previa was 51.6% (95% CI 42.7–60.6) in a heterogeneous set of studies (I2 = 97.9). Correlation analysis found that there was a positive correlation between prevalence and percentage of multiparous (r = 0.534, P = 0.027) and a negative correlation between prevalence and survey year (r = −0.400, P = 0.031). In conclusion, the prevalence of APH was a high condition among pregnant women with placenta previa. PMID:28067303

Instruments for assessing the risk of falls in acute hospitalized patients: a systematic review and meta-analysis

PubMed Central

2013-01-01

Background Falls are a serious problem for hospitalized patients, reducing the duration and quality of life. It is estimated that over 84% of all adverse events in hospitalized patients are related to falls. Some fall risk assessment tools have been developed and tested in environments other than those for which they were developed with serious validity discrepancies. The aim of this review is to determine the accuracy of instruments for detecting fall risk and predicting falls in acute hospitalized patients. Methods Systematic review and meta-analysis. Main databases, related websites and grey literature were searched. Two blinded reviewers evaluated title and abstracts of the selected articles and, if they met inclusion criteria, methodological quality was assessed in a new blinded process. Meta-analyses of diagnostic ORs (DOR) and likelihood (LH) coefficients were performed with the random effects method. Forest plots were calculated for sensitivity and specificity, DOR and LH. Additionally, summary ROC (SROC) curves were calculated for every analysis. Results Fourteen studies were selected for the review. The meta-analysis was performed with the Morse (MFS), STRATIFY and Hendrich II Fall Risk Model scales. The STRATIFY tool provided greater diagnostic validity, with a DOR value of 7.64 (4.86 - 12.00). A meta-regression was performed to assess the effect of average patient age over 65 years and the performance or otherwise of risk reassessments during the patient’s stay. The reassessment showed a significant reduction in the DOR on the MFS (rDOR 0.75, 95% CI: 0.64 - 0.89, p = 0.017). Conclusions The STRATIFY scale was found to be the best tool for assessing the risk of falls by hospitalized acutely-ill adults. However, the behaviour of these instruments varies considerably depending on the population and the environment, and so their operation should be tested prior to implementation. Further studies are needed to investigate the effect of the reassessment of these instruments with respect to hospitalized adult patients, and to consider the real compliance by healthcare personnel with procedures related to patient safety, and in particular concerning the prevention of falls. PMID:23547708

The validity of three fall risk screening tools in an acute geriatric inpatient population.

PubMed

Latt, Mark Dominic; Loh, K Florence; Ge, Ludi; Hepworth, Annie

2016-09-01

We examined the validity of the Ontario Modified STRATIFY (OM) (St Thomas's Risk Assessment Tool in Falling Elderly Inpatients), The Northern Hospital Modified STRATIFY (TNH) and STRATIFY in predicting falls in an acute aged care unit. Data were collected prospectively from 217 people presenting consecutively and falls identified during hospitalisation. Sensitivities of OM (80.0, 95% confidence interval (CI) 58.4 to 91.9%), TNH (85, CI 64.0 to 94.8%) and STRATIFY (80.0, CI 58.4 to 91.0%) were similar. The STRATIFY had higher specificity (61.4, CI 54.5 to 67.9%) than OM (37.1, CI 30.6 to 44.0%) and TNH (51.3, CI 44.3 to 58.2%). Accuracy (percentage of patients correctly classified as 'faller' or 'non-faller') was higher using STRATIFY (63.1, CI 56.5 to 69.3%) and TNH (54.4, CI 47.8 to 61.0%) than with OM (41.0, CI 34.7 to 47.7%, P < 0.0001). Screening tools have limited accuracy in identifying patients at high risk of falls. © 2016 AJA Inc.

SPONTANEOUS FORMATION OF SURFACE MAGNETIC STRUCTURE FROM LARGE-SCALE DYNAMO IN STRONGLY STRATIFIED CONVECTION

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

Masada, Youhei; Sano, Takayoshi, E-mail: ymasada@auecc.aichi-edu.ac.jp, E-mail: sano@ile.osaka-u.ac.jp

We report the first successful simulation of spontaneous formation of surface magnetic structures from a large-scale dynamo by strongly stratified thermal convection in Cartesian geometry. The large-scale dynamo observed in our strongly stratified model has physical properties similar to those in earlier weakly stratified convective dynamo simulations, indicating that the α {sup 2}-type mechanism is responsible for the dynamo. In addition to the large-scale dynamo, we find that large-scale structures of the vertical magnetic field are spontaneously formed in the convection zone (CZ) surface only in cases with a strongly stratified atmosphere. The organization of the vertical magnetic field proceedsmore » in the upper CZ within tens of convective turnover time and band-like bipolar structures recurrently appear in the dynamo-saturated stage. We consider several candidates to be possibly be the origin of the surface magnetic structure formation, and then suggest the existence of an as-yet-unknown mechanism for the self-organization of the large-scale magnetic structure, which should be inherent in the strongly stratified convective atmosphere.« less

Geohydrology of the Gallup's Quarry area, Plainfield, Connecticut

USGS Publications Warehouse

Melvin, Robert L.; Stone, Janet Radway; Craft, Patrick A.; Lane, John W.

1995-01-01

The geohydrology of the Gallup's Quarry area in Plainfield, Connecticut was characterized by the U.S. Geological Survey, in cooperation with the U.S. Environmental Protection Agency, to provide a preliminary framework for future remedial efforts. Gallup's Quarry, an inactive sand and gravel pit, was the site of unregulated disposal of an unknown volume of chemical wastes from at least the summer of 1977 until January 1978. Existing information collected for the Connecticut Department of Environmental Protection during 1978-82 showed that ground water beneath Gallup's Quarry and adjacent land to the northwest was contaminated by organic and inorganic compounds. There is also some evidence for contamination of Mill Brook, which is located north and northwest of the disposal areas. Geologic mapping and subsurface data show that unconsolidated surficial materials up to 90 feet thick overlie fractured crystalline bedrock in most of the Gallup's Quarry area. The surficial materials consist primarily of stratified drift and till. Texture changes vertically and laterally within the stratified drift; grain size ranges from very coarse to fine. Till blankets the bedrock surface beneath the stratified drift and is a few feet to as much as 25 feet thick. Bedrock is exposed at land surface in a hill in the southeastern part of the quarry and slopes to depths of up to 90 feet beneath the area west and north of the disposal sites. The bedrock is a dark, fine-grained, fractured and jointed blastomylonite and hornblende gneiss of the Quinebaug Formation. It is likely that a west- northwest-trending fault is present in the bedrock beneath Gallup's Quarry; this fault, if present, may provide a preferential pathway for ground-water flow and contaminant transport. The principal horizontal direction of ground-water flow and movement of dissolved contaminants in the stratified drift was to the northwest of the waste-disposal areas toward Mill Brook in 1978. Estimates of average annual recharge based on regional analyses for 1978-91 are 30 inches in areas where stratified drift are exposed and 9.6 inches in areas where till and crystalline bedrock are exposed. The hydraulic conductivity of the coarse-grained stratified drift, identified in earlier U.S. Geological Survey studies as part of an aquifer capable of yielding large quantities of water, may be several hundred feet per day. The hydraulic conductivity of the till, based on regional information, is likely 0.04 to 24 feet per day. More detailed geohydrologic information is required to develop effective remedial programs at Gallup's Quarry, particularly in the areas north and west of the waste-disposal areas. Detailed subsurface geologic mapping and definition of head distribution and other hydraulic properties of each geohydrologic unit would indicate directions and rates of ground-water flow. Most importantly, the present extent of contamination of water and sediments throughout the area will have to be determined.

Impact of statins on cognitive deficits in adult male rodents after traumatic brain injury: a systematic review.

PubMed

Peng, Weijun; Yang, Jingjing; Yang, Bo; Wang, Lexing; Xiong, Xin-gui; Liang, Qinghua

2014-01-01

The efficacy of statin treatment on cognitive decline is controversial, and the effect of statins on cognitive deficits in individuals with traumatic brain injury (TBI) has yet to be investigated. Therefore, we systematically reviewed the effect of statins on cognitive deficits in adult male rodents after TBI. After identifying eligible studies by searching four electronic databases on February 28, 2014, we assessed study quality, evaluated the efficacy of statin treatment, and performed stratified metaregression and metaregression to assess the influence of study design on statin efficacy. Eleven studies fulfilled our inclusion criteria from a total of 183 publications. The overall methodological quality of these studies was poor. Meta-analysis showed that statins exert statistically significant positive effects on cognitive performance after TBI. Stratified analysis showed that atorvastatin has the greatest effect on acquisition memory, simvastatin has the greatest effect on retention memory, and statin effects on acquisition memory are higher in closed head injury models. Metaregression analysis further showed that that animal species, study quality, and anesthetic agent impact statin effects on retention memory. We conclude that statins might reduce cognitive deficits after TBI. However, additional well-designed and well-reported animal studies are needed to inform further clinical study.

Palliative interventions for hepatocellular carcinoma patients: analysis of the National Cancer Database.

PubMed

Hammad, Abdulrahman Y; Robbins, Jared R; Turaga, Kiran K; Christians, Kathleen K; Gamblin, T Clark; Johnston, Fabian M

2017-01-01

Palliative therapies are provided to a subset of hepatocellular carcinoma (HCC) patients with the aim of providing symptomatic relief, better quality of life and improved survival. The present study sought to assess and compare the efficacy of different palliative therapies for HCC. The National Cancer Database (NCDB), a retrospective national database that captures approximately 70% of all patients treated for cancer in the US, was queried for patients with HCC who were deemed unresectable from 1998-2011. Patients were stratified by receipt of palliative therapy. Survival analysis was examined by log-rank test and Kaplan Meier curves, and a multivariate proportional hazards model was utilized to identify the predictors of survival. A total of 3,267 patients were identified; 287 (8.7%) received surgical palliation, 827 (25.3%) received radiotherapy (RT), 877 (26.8%) received chemotherapy, 1,067 (32.6%) received pain management therapy, while 209 (6.4%) received a combination of the previous three modalities. On multivariate analysis palliative RT was identified as a positive predictor of survival [hazards ratio (HR) 0.65; 95% CI, 0.50-0.83]. Stratifying by disease stage, palliative RT provided a significant survival benefit for patients with stage IV disease. Palliative RT appears to extend survival and should be considered for patients presenting with late stage HCC.

Texting to increase physical activity in teens: Development & preliminary

USDA-ARS?s Scientific Manuscript database

Our purpose was to present formative research and preliminary results for a self-determination-theory (SDT)-based text messages to promote physical activity (PA) among teens. Thirty 14- to 17-year olds, stratified by gender and race/ethnicity (Black, Hispanic, White), were recruited to participate i...

Representativeness-based sampling network design for the State of Alaska

Treesearch

Forrest M. Hoffman; Jitendra Kumar; Richard T. Mills; William W. Hargrove

2013-01-01

Resource and logistical constraints limit the frequency and extent of environmental observations, particularly in the Arctic, necessitating the development of a systematic sampling strategy to maximize coverage and objectively represent environmental variability at desired scales. A quantitative methodology for stratifying sampling domains, informing site selection,...

Self-identity Changes and English Learning among Chinese Undergraduates.

ERIC Educational Resources Information Center

Yihong, Gao; Ying, Cheng; Yuan, Zhao; Yan, Zhou

2005-01-01

This quantitative study investigated Chinese college students' self-identity changes associated with English learning. The subjects were 2,278 undergraduates from 30 universities, obtained from a stratified sampling. Based on existing literature of bilinguals identities, the self-designed questionnaire defined six categories of self-identity…

Multi-Sensory Intervention Observational Research

ERIC Educational Resources Information Center

Thompson, Carla J.

2011-01-01

An observational research study based on sensory integration theory was conducted to examine the observed impact of student selected multi-sensory experiences within a multi-sensory intervention center relative to the sustained focus levels of students with special needs. A stratified random sample of 50 students with severe developmental…

Efficacy and Safety of the SGLT2 Inhibitor Luseogliflozin in Japanese Patients With Type 2 Diabetes Mellitus Stratified According to Baseline Body Mass Index: Pooled Analysis of Data From 52-Week Phase III Trials.

PubMed

Sakai, Soichi; Kaku, Kohei; Seino, Yutaka; Inagaki, Nobuya; Haneda, Masakazu; Sasaki, Takashi; Fukatsu, Atsushi; Kakiuchi, Haruka; Samukawa, Yoshishige

2016-04-01

Luseogliflozin, a sodium-glucose cotransporter-2 inhibitor, may be beneficial in obese diabetic patients based on its potential to decrease blood glucose and body weight, but there is limited proof. This analysis aimed to investigate the efficacy and safety of luseogliflozin in patients with varying levels of obesity. A pooled analysis of four 52-week Phase III trials of luseogliflozin 2.5 mg daily (or up to 5 mg daily) in Japanese patients with type 2 diabetes mellitus stratified according to baseline body mass index (BMI) was conducted. Efficacy end points included changes in glycosylated hemoglobin (HbA1c), fasting plasma glucose (FPG), and body weight. In total, 1031 patients were included and stratified into 5 BMI (kg/m(2)) groups: low-to-medium (<22.5, n = 222); medium (≥22.5 to <25, n = 270); high-level 1 (≥25 to <27.5, n = 262); high-level 2 (≥27.5 to <30, n = 142); and very-high (≥30, n = 135). HbA1c decreased significantly compared with baseline until week 52 in all groups, and a similar trend was observed with FPG and body weight. The reduction in glycemic parameters tended to be slightly smaller in patients with BMI <22.5 kg/m(2), and the reduction in body weight tended to be greater in patients with higher BMI, especially those with BMI ≥30 kg/m(2). Levels of fasting insulin, C-peptide immunoreactivity, triglyceride, blood pressure, aspartate aminotransferase, alanine aminotransferase, and uric acid decreased significantly at week 52 in all groups (except for aspartate aminotransferase in patients with BMI <22.5 kg/m(2)). Levels of these parameters tended to be higher at baseline and these enhanced levels resulted in a greater decrease in patients with higher BMI. In safety, the incidence of adverse events was similar between groups, and most of them were mild in severity. HbA1c and body weight decreased significantly in all groups. Decrease in glycemic parameters tended to be smaller in patients with BMI <22.5 kg/m(2), while that of body weight was larger in patients with higher BMI. Furthermore, luseogliflozin was especially beneficial in patients with higher BMI in terms of metabolic abnormalities, including insulin secretion and hypertension. Luseogliflozin exhibited a favorable and similar safety profile over 52 weeks in all groups. This agent can be an effective and well-tolerated therapeutic option in patients with a wide range of BMI levels, and it may be more beneficial in patients with higher BMI. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Comparison of survival between radiation therapy and trans-oral laser microsurgery for early glottic cancer patients; a retrospective cohort study.

PubMed

De Santis, R J; Poon, I; Lee, J; Karam, I; Enepekides, D J; Higgins, K M

2016-08-02

The literature reports various treatment methodologies, such as trans-oral laser microsurgery, radiation therapy, total/partial laryngectomies, and concurrent radiation chemotherapy for patients with early larynx cancer. However, at the forefront of early glottis treatment is trans-oral laser microsurgery and radiation therapy, likely due to better functional and survival outcomes. Here we conduct the largest Canadian head-to-head comparison of consecutive patients treated with either radiation therapy or trans-oral laser microsurgery. Additionally, we compare these two treatments and their 5-year survival rates post treatment to add to the existing literature. Charts of patients who were diagnosed with early glottic cancer between 2006 and 2013 were reviewed. Seventy-five patients were identified, and split into 2 groups based on their primary treatment, trans-oral laser microsurgery and radiation therapy. Kaplan-Meier survival curves, life-tables, and the log-rank statistic were reported to determine if there was a difference between the two treatment groups and their disease-specific survival, disease-free survival, and total laryngectomy-free survival. Additionally, each different survival analysis was stratified by potential confounding variables, to help conclude which treatment is more efficacious in this population. The 5-year disease-specific survival rate is 93.3 % σ = 0.063 and 90.8 % σ = 0.056 for patients treated with trans-oral laser microsurgery and radiation therapy, respectively (χ (2) < 0.001, p = 0.983). The disease free survival rate is 60.0 % (σ =0.121) for patients treated with trans-oral laser microsurgery, and 67.2 % (σ = 0.074) for those who received RT (χ (2) = 0.19, p = 0.663). Additionally, the total laryngectomy-free survival rate is 84.1 % (σ = 0.1) and 79.1 % (σ = 0.072) for patients' early glottic cancer treated by trans-oral laser microsurgery and radiation therapy, respectively (χ (2) = 0.235, p = 0.628). Chi-square analysis of age-group versus treatment group (χ (2) = 6.455, p = 0.04) and T-stage versus treatment group (χ (2) = 11.3, p = 0.001) revealed a statistically significant relationship, suggesting survival analysis should be stratified by these variables. However, after stratification, there was no statistically significant difference between the trans-oral laser microsurgery and radiation therapy groups in any of the survival analyses. No difference was demonstrated in the 5-year disease-specific survival, disease-free survival, and total laryngectomy-free survival, between the RT and TLM treatment groups. Additionally, both groups showed similar 5-year survival after stratifying by confounding variables.

Postpartum pelvic floor muscle training and urinary incontinence: a randomized controlled trial.

PubMed

Hilde, Gunvor; Stær-Jensen, Jette; Siafarikas, Franziska; Ellström Engh, Marie; Bø, Kari

2013-12-01

To evaluate whether postpartum pelvic floor muscle training decrease prevalence of any urinary incontinence (UI) in primiparous women with and without UI at inclusion (mixed population) and further to perform stratified analyses on women with and without major levator ani muscle defects. A two-armed assessor-blinded randomized controlled trial including primiparous women 6 weeks after vaginal delivery was conducted. Participants were stratified on major levator ani muscle defects, verified by transperineal ultrasonography, and thereafter randomly allocated to training or control. All participants were taught to contract the pelvic floor muscles. The control participants received no further intervention, whereas training participants attended a weekly supervised pelvic floor muscle training class and performed daily home exercise for 16 weeks. Primary outcome was self-reported UI analyzed by relative risk. We included 175 women, 55 with major levator ani muscle defects and 120 without. Prevalence of UI at baseline was 39.1% in the training group (n=87) and 50% among those in the control group (n=88). Fifteen women (8.6%) were lost to follow-up. At 6 months after delivery (postintervention), 34.5% and 38.6% reported UI in the training and control groups, respectively. Relative risk analysis of UI gave a nonsignificant effect size of 0.89 (95% confidence interval [CI] 0.60-1.32). Results were similar for the stratum with and without major levator ani muscle defects, 0.89 (95% CI 0.51-1.56) and 0.90 (95% CI 0.53-1.52), respectively. Postpartum pelvic floor training did not decrease UI prevalence 6 months after delivery in primiparous women. Stratified analysis on women with and without major levator ani muscle defects showed similar nonsignificant results. ClinicalTrials.gov, www.clinicaltrials.gov, NCT01069484. : I.

Case-Crossover Analysis of Air Pollution Health Effects: A Systematic Review of Methodology and Application

PubMed Central

Carracedo-Martínez, Eduardo; Taracido, Margarita; Tobias, Aurelio; Saez, Marc; Figueiras, Adolfo

2010-01-01

Background Case-crossover is one of the most used designs for analyzing the health-related effects of air pollution. Nevertheless, no one has reviewed its application and methodology in this context. Objective We conducted a systematic review of case-crossover (CCO) designs used to study the relationship between air pollution and morbidity and mortality, from the standpoint of methodology and application. Data sources and extraction A search was made of the MEDLINE and EMBASE databases. Reports were classified as methodologic or applied. From the latter, the following information was extracted: author, study location, year, type of population (general or patients), dependent variable(s), independent variable(s), type of CCO design, and whether effect modification was analyzed for variables at the individual level. Data synthesis The review covered 105 reports that fulfilled the inclusion criteria. Of these, 24 addressed methodological aspects, and the remainder involved the design’s application. In the methodological reports, the designs that yielded the best results in simulation were symmetric bidirectional CCO and time-stratified CCO. Furthermore, we observed an increase across time in the use of certain CCO designs, mainly symmetric bidirectional and time-stratified CCO. The dependent variables most frequently analyzed were those relating to hospital morbidity; the pollutants most often studied were those linked to particulate matter. Among the CCO-application reports, 13.6% studied effect modification for variables at the individual level. Conclusions The use of CCO designs has undergone considerable growth; the most widely used designs were those that yielded better results in simulation studies: symmetric bidirectional and time-stratified CCO. However, the advantages of CCO as a method of analysis of variables at the individual level are put to little use. PMID:20356818

The sociodemographic patterning of opposition to raising taxes on tobacco and restricting tobacco advertisements in Argentina.

PubMed

Konfino, J; De Maio, F; Ondarsuhu, D; Goldberg, L; Linetzky, B; Ferrante, D

2015-04-01

Argentina has enacted important tobacco control initiatives in recent years. Yet little is known about the social patterning of attitudes toward tobacco control. Research is needed to explore what predicts opposition to tobacco control initiatives such as higher taxes on tobacco and the prohibition of tobacco advertising. Secondary analysis of Argentina's Global Adult Tobacco Survey (N = 6645). Binary logistic regression analysis examining opposition to raising tobacco taxes and banning tobacco publicity. Models were stratified by smoking status. Respondents generally indicated very little opposition to either tobacco control measure, with only 15.6% of respondents opposed to increasing taxes on tobacco products and 9.6% opposed to banning tobacco advertisements. Smoking status is the most important predictor of opposition to increasing taxes (OR = 7.85, 95% CI = 6.60-9.34) and banning advertisements (OR = 1.72, 95% CI = 1.39-2.11). Opposition to these measures is most likely among young respondents (aged 15-24) and least likely among older age groups (55-64 and 65 or over), compared to the 25-34 age group. Stratified models suggest that the effect of age may be different for smokers and non-smokers. Low income is a significant predictor of opposition, but only in stratified models for smokers. There is general support for stronger tobacco control measures in Argentina. Opposition to raising taxes on tobacco products and banning tobacco advertisement appears to be concentrated among young smokers with low and medium levels of household income. Copyright © 2015 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

Race influences warfarin dose changes associated with genetic factors

PubMed Central

Brown, Todd M.; Yan, Qi; Thigpen, Jonathan L.; Shendre, Aditi; Liu, Nianjun; Hill, Charles E.; Arnett, Donna K.; Beasley, T. Mark

2015-01-01

Warfarin dosing algorithms adjust for race, assigning a fixed effect size to each predictor, thereby attenuating the differential effect by race. Attenuation likely occurs in both race groups but may be more pronounced in the less-represented race group. Therefore, we evaluated whether the effect of clinical (age, body surface area [BSA], chronic kidney disease [CKD], and amiodarone use) and genetic factors (CYP2C9*2, *3, *5, *6, *11, rs12777823, VKORC1, and CYP4F2) on warfarin dose differs by race using regression analyses among 1357 patients enrolled in a prospective cohort study and compared predictive ability of race-combined vs race-stratified models. Differential effect of predictors by race was assessed using predictor-race interactions in race-combined analyses. Warfarin dose was influenced by age, BSA, CKD, amiodarone use, and CYP2C9*3 and VKORC1 variants in both races, by CYP2C9*2 and CYP4F2 variants in European Americans, and by rs12777823 in African Americans. CYP2C9*2 was associated with a lower dose only among European Americans (20.6% vs 3.0%, P < .001) and rs12777823 only among African Americans (12.3% vs 2.3%, P = .006). Although VKORC1 was associated with dose decrease in both races, the proportional decrease was higher among European Americans (28.9% vs 19.9%, P = .003) compared with African Americans. Race-stratified analysis improved dose prediction in both race groups compared with race-combined analysis. We demonstrate that the effect of predictors on warfarin dose differs by race, which may explain divergent findings reported by recent warfarin pharmacogenetic trials. We recommend that warfarin dosing algorithms should be stratified by race rather than adjusted for race. PMID:26024874

Race influences warfarin dose changes associated with genetic factors.

PubMed

Limdi, Nita A; Brown, Todd M; Yan, Qi; Thigpen, Jonathan L; Shendre, Aditi; Liu, Nianjun; Hill, Charles E; Arnett, Donna K; Beasley, T Mark

2015-07-23

Warfarin dosing algorithms adjust for race, assigning a fixed effect size to each predictor, thereby attenuating the differential effect by race. Attenuation likely occurs in both race groups but may be more pronounced in the less-represented race group. Therefore, we evaluated whether the effect of clinical (age, body surface area [BSA], chronic kidney disease [CKD], and amiodarone use) and genetic factors (CYP2C9*2, *3, *5, *6, *11, rs12777823, VKORC1, and CYP4F2) on warfarin dose differs by race using regression analyses among 1357 patients enrolled in a prospective cohort study and compared predictive ability of race-combined vs race-stratified models. Differential effect of predictors by race was assessed using predictor-race interactions in race-combined analyses. Warfarin dose was influenced by age, BSA, CKD, amiodarone use, and CYP2C9*3 and VKORC1 variants in both races, by CYP2C9*2 and CYP4F2 variants in European Americans, and by rs12777823 in African Americans. CYP2C9*2 was associated with a lower dose only among European Americans (20.6% vs 3.0%, P < .001) and rs12777823 only among African Americans (12.3% vs 2.3%, P = .006). Although VKORC1 was associated with dose decrease in both races, the proportional decrease was higher among European Americans (28.9% vs 19.9%, P = .003) compared with African Americans. Race-stratified analysis improved dose prediction in both race groups compared with race-combined analysis. We demonstrate that the effect of predictors on warfarin dose differs by race, which may explain divergent findings reported by recent warfarin pharmacogenetic trials. We recommend that warfarin dosing algorithms should be stratified by race rather than adjusted for race. © 2015 by The American Society of Hematology.

Creation of a Prognostic Index for Spine Metastasis to Stratify Survival in Patients Treated With Spinal Stereotactic Radiosurgery: Secondary Analysis of Mature Prospective Trials

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

Tang, Chad; Hess, Kenneth; Bishop, Andrew J.

Purpose: There exists uncertainty in the prognosis of patients following spinal metastasis treatment. We sought to create a scoring system that stratifies patients based on overall survival. Methods and Materials: Patients enrolled in 2 prospective trials investigating stereotactic spine radiation surgery (SSRS) for spinal metastasis with ≥3-year follow-up were analyzed. A multivariate Cox regression model was used to create a survival model. Pretreatment variables included were race, sex, age, performance status, tumor histology, extent of vertebrae involvement, previous therapy at the SSRS site, disease burden, and timing of diagnosis and metastasis. Four survival groups were generated based on the model-derivedmore » survival score. Results: Median follow-up in the 206 patients included in this analysis was 70 months (range: 37-133 months). Seven variables were selected: female sex (hazard ratio [HR] = 0.7, P=.02), Karnofsky performance score (HR = 0.8 per 10-point increase above 60, P=.007), previous surgery at the SSRS site (HR = 0.7, P=.02), previous radiation at the SSRS site (HR = 1.8, P=.001), the SSRS site as the only site of metastatic disease (HR = 0.5, P=.01), number of organ systems involved outside of bone (HR = 1.4 per involved system, P<.001), and >5 year interval from initial diagnosis to detection of spine metastasis (HR = 0.5, P<.001). The median survival among all patients was 25.5 months and was significantly different among survival groups (in group 1 [excellent prognosis], median survival was not reached; group 2 reached 32.4 months; group 3 reached 22.2 months; and group 4 [poor prognosis] reached 9.1 months; P<.001). Pretreatment symptom burden was significantly higher in the patient group with poor survival than in the group with excellent survival (all metrics, P<.05). Conclusions: We developed the prognostic index for spinal metastases (PRISM) model, a new model that identified patient subgroups with poor and excellent prognoses.« less

Retrospective study of long-term outcome after brain arteriovenous malformation rupture: the RAP score.

PubMed

Shotar, Eimad; Debarre, Matthieu; Sourour, Nader-Antoine; Di Maria, Federico; Gabrieli, Joseph; Nouet, Aurélien; Chiras, Jacques; Degos, Vincent; Clarençon, Frédéric

2018-01-01

OBJECTIVE The authors aimed to design a score for stratifying patients with brain arteriovenous malformation (BAVM) rupture, based on the likelihood of a poor long-term neurological outcome. METHODS The records of consecutive patients with BAVM hemorrhagic events who had been admitted over a period of 11 years were retrospectively reviewed. Independent predictors of a poor long-term outcome (modified Rankin Scale score ≥ 3) beyond 1 year after admission were identified. A risk stratification scale was developed and compared with the intracranial hemorrhage (ICH) score to predict poor outcome and inpatient mortality. RESULTS One hundred thirty-five patients with 139 independent hemorrhagic events related to BAVM rupture were included in this analysis. Multivariate logistic regression followed by stepwise analysis showed that consciousness level according to the Glasgow Coma Scale (OR 6.5, 95% CI 3.1-13.7, p < 10 -3 ), hematoma volume (OR 1.8, 95% CI 1.2-2.8, p = 0.005), and intraventricular hemorrhage (OR 7.5, 95% CI 2.66-21, p < 10 -3 ) were independently associated with a poor outcome. A 12-point scale for ruptured BAVM prognostication was constructed combining these 3 factors. The score obtained using this new scale, the ruptured AVM prognostic (RAP) score, was a stronger predictor of a poor long-term outcome (area under the receiver operating characteristic curve [AUC] 0.87, 95% CI 0.8-0.92, p = 0.009) and inpatient mortality (AUC 0.91, 95% CI 0.85-0.95, p = 0.006) than the ICH score. For a RAP score ≥ 6, sensitivity and specificity for predicting poor outcome were 76.8% (95% CI 63.6-87) and 90.8% (95% CI 81.9-96.2), respectively. CONCLUSIONS The authors propose a new admission score, the RAP score, dedicated to stratifying the risk of poor long-term outcome after BAVM rupture. This easy-to-use scoring system may help to improve communication between health care providers and consistency in clinical research. Only external prospective cohorts and population-based studies will ensure full validation of the RAP scores' capacity to predict outcome after BAVM rupture.

Analysis of hepatocyte growth factor immunostaining in the placenta of HIV-infected normotensive versus preeclamptic pregnant women.

PubMed

Cele, S B; Odun-Ayo, F; Onyangunga, O A; Moodley, J; Naicker, T

2018-08-01

Hepatocyte Growth Factor (HGF) plays a role in the migration and morphogenesis of different cell types and tissues. Preeclampsia (PE) is associated with deficient trophoblast invasion and placental insufficiency; hence HGF production is expected to be compromised. This study therefore aimed to immunolocalize and morphometrically analyse placental HGF in normotensive versus PE pregnancies stratified by HIV status and gestational age. Normotensive (N; n = 40) and preeclamptic (PE; n = 80) women were stratified by HIV status (HIV- and HIV+), and gestational age i.e. early onset of PE (EOPE; <34 weeks) and late onset of PE (LOPE; ≥34 weeks). Placental tissues were stained using conventional immunohistochemistry, performed using mouse anti-human HGF antibody. Morphometric image analysis was performed using Zeiss Axio-Vision software. HGF was immuno-localized within the syncytiotrophoblast, cytotrophoblast, endothelial and fibroblast-like cell populations of both conducting and exchange villi. Based on pregnancy type, HGF immunoexpression within the conducting villi was significantly different between Nvs EOPE (p = 0.0372) and EOPE vs LOPE (p = 0.0006). Within the exchange villi, no significant difference of HGF immunostaining was noted between N vs EOPE and N vs LOPE. A down-regulation of HGF immuno-expression was observed in LOPE compared to other groups within both villi types, albeit non-significant. Based on HIV status, no significant difference in HGF immuno-expression was demonstrated between HIV- vs HIV + within the exchange and conducting villi. However, the expression of HGF in HIV- group was elevated in both villi types. Across the groups, a significant difference was found between N+ vs EOPE- (p  = 0.0207), EOPE+ vs LOPE- (p = 0.0036) and EOPE- vs LOPE- (p = 0.0016) of the conducting villi while no significant difference was found within the exchange villi. This novel study demonstrates that HGF was two-fold higher in conducting compared to exchange villi irrespective of the pregnancy type. HIV infection does not influence HGF expression within the conducting and exchange villi. The HGF/c-MET receptor complex may modulate the ligand expression within the placenta. Copyright © 2018 Elsevier B.V. All rights reserved.

Developmental changes in hippocampal shape among preadolescent children.

PubMed

Lin, Muqing; Fwu, Peter T; Buss, Claudia; Davis, Elysia P; Head, Kevin; Muftuler, L Tugan; Sandman, Curt A; Su, Min-Ying

2013-11-01

It is known that the largest developmental changes in the hippocampus take place during the prenatal period and during the first two years of postnatal life. Few studies have been conducted to address the normal developmental trajectory of the hippocampus during childhood. In this study shape analysis was applied to study the normal developing hippocampus in a group of 103 typically developing 6- to 10-year-old preadolescent children. The individual brain was normalized to a template, and then the hippocampus was manually segmented and further divided into the head, body, and tail sub-regions. Three different methods were applied for hippocampal shape analysis: radial distance mapping, surface-based template registration using the robust point matching (RPM) algorithm, and volume-based template registration using the Demons algorithm. All three methods show that the older children have bilateral expanded head segments compared to the younger children. The results analyzed based on radial distance to the centerline were consistent with those analyzed using template-based registration methods. In analyses stratified by sex, it was found that the age-associated anatomical changes were similar in boys and girls, but the age-association was strongest in girls. Total hippocampal volume and sub-regional volumes analyzed using manual segmentation did not show a significant age-association. Our results suggest that shape analysis is sensitive to detect sub-regional differences that are not revealed in volumetric analysis. The three methods presented in this study may be applied in future studies to investigate the normal developmental trajectory of the hippocampus in children. They may be further applied to detect early deviations from the normal developmental trajectory in young children for evaluating susceptibility for psychopathological disorders involving hippocampus. Copyright © 2013 ISDN. Published by Elsevier Ltd. All rights reserved.

Subanalysis of the CONFIRM Registries: Acute Procedural Outcomes in Claudicant and Critical Limb Ischemia Patients With Varying Levels of Calcification Treated for Peripheral Arterial Disease With Orbital Atherectomy.

PubMed

Adams, George L; Das, Tony; Lee, Michael S; Beasley, Robert; Mustapha, Jihad

2015-11-01

Patients with peripheral arterial disease (PAD) can be classified into groups based upon the severity of the disease using the Rutherford classification system. This analysis compares the procedural outcomes of PAD patients treated with orbital atherectomy stratified by Rutherford class (1-3 = intermittent claudication; 4-6 = critical limb ischemia [CLI]), and acute angiographic outcomes of these patients stratified by degree of lesion calcification. The CONFIRM registry series was analyzed and included 1697 patients with intermittent claudication (Rutherford class 1-3) and 1320 patients with CLI (Rutherford class 4-6) treated with orbital atherectomy. The composite rate of dissection, perforation, slow-flow, vessel closure, spasm, embolism, and thrombus formation was compared between claudicants and CLI patients with varying degrees of lesion calcification. Patients with CLI were older and had a higher prevalence of diabetes, coronary artery disease, and renal disease (P<.001). Claudicants with moderately/severely calcified lesions had a lower rate of dissection (both non-flow limiting and flow-limiting) than claudicants with mildly/minimally calcified lesions. CLI patients with mildly/minimally calcified lesions had higher rates of embolism and thrombus than CLI patients with moderately/severely calcified lesions. Plaque modification with orbital atherectomy resulted in similar low procedural complication rates in the CLI group compared with the claudicant group. These results suggest that orbital atherectomy is safe and effective for treating calcified lesions in high-risk patients with varying severity of PAD symptoms.

Current and Future Carbon Budgets of Tropical Rain Forest: A Cross Scale Analysis. Final Report

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

Oberbauer, S. F.

2004-01-16

The goal of this project was to make a first assessment of the major carbon stocks and fluxes and their climatic determinants in a lowland neotropical rain forest, the La Selva Biological Station, Costa Rica. Our research design was based on the concurrent use of several of the best available approaches, so that data could be cross-validated. A major focus of our effort was to combine meteorological studies of whole-forest carbon exchange (eddy flux), with parallel independent measurements of key components of the forest carbon budget. The eddy flux system operated from February 1998 to February 2001. To obtain fieldmore » data that could be scaled up to the landscape level, we monitored carbon stocks, net primary productivity components including tree growth and mortality, litterfall, woody debris production, root biomass, and soil respiration in a series of replicated plots stratified across the major environmental gradients of the forest. A second major focus of this project was on the stocks and changes of carbon in the soil. We used isotope studies and intensive monitoring to investigate soil organic stocks and the climate-driven variation of soil respiration down the soil profile, in a set of six 4m deep soil shafts stratified across the landscape. We measured short term tree growth, climate responses of sap flow, and phenology in a suite of ten canopy trees to develop individual models of tree growth to daytime weather variables.« less

Familial Risk of Biliary Tract Cancers: A Population-Based Study in Utah.

PubMed

Samadder, N Jewel; Smith, Ken Robert; Wong, Jathine; Hanson, Heidi; Boucher, Kenneth; Burt, Randall W; Charlton, Michael; Byrne, Kathryn R; Gallegos-Orozco, Juan F; Koptiuch, Cathryn; Curtin, Karen

2016-12-01

Biliary tract cancers (BTC) including, cholangiocarcinoma (CC) and gallbladder cancer (GBC), are rare and highly fatal malignancies. The etiology and inherited susceptibility of both malignancies are poorly understood. We quantified the risk of BTC in first-degree (FDR), second-degree (SDR), and first cousin (FC) relatives of individuals with BTC, stratified by tumor subsite. BTC diagnosed between 1980 and 2011 were identified from the Utah Cancer Registry and linked to pedigrees from the Utah Population Database. Age- and gender-matched BTC-free controls were selected to form the comparison group for determining BTC risk in relatives using Cox regression analysis. Of the 1302 index patients diagnosed with BTC, 550 (42.2 %) were located in the gallbladder and 752 (57.8 %) were cholangiocarcinomas. There was no elevated risk of BTC (all subsites combined) in FDRs (HR 0.94, 95 % CI 0.29-3.0), SDRs (HR 0.25, 95 % CI 0.06-1.03), and FCs (HR 0.96, 95 % CI 0.61-1.51) of BTC cases compared to cancer-free controls. Similarly, no increased familial risk of GBC or CC was found in relatives of BTC patients stratified by tumor subsite compared to relatives of controls. Relatives of BTC patients are not at an increased risk of GBC or CC in a statewide population. This suggests that biliary tract cancer risk is not associated with a familial predisposition and may be mitigated more strongly by environmental modifiers.

Statistical and Graphical Assessment of Circumferential and Radial Hardness Variation of AISI 4140, AISI 1020 and AA 6082 Aluminum Alloy

PubMed Central

Al-Khalid, Hamad; Alaskari, Ayman; Oraby, Samy

2011-01-01

Hardness homogeneity of the commonly used structural ferrous and nonferrous engineering materials is of vital importance in the design stage, therefore, reliable information regarding material properties homogeneity should be validated and any deviation should be addressed. In the current study the hardness variation, over wide spectrum radial locations of some ferrous and nonferrous structural engineering materials, was investigated. Measurements were performed over both faces (cross-section) of each stock bar according to a pre-specified stratified design, ensuring the coverage of the entire area both in radial and circumferential directions. Additionally the credibility of the apparatus and measuring procedures were examined through a statistically based calibration process of the hardness reference block. Statistical and response surface graphical analysis are used to examine the nature, adequacy and significance of the measured hardness values. Calibration of the apparatus reference block proved the reliability of the measuring system, where no strong evidence was found against the stochastic nature of hardness measures over the various stratified locations. Also, outlier elimination procedures were proved to be beneficial only at fewer measured points. Hardness measurements showed a dispersion domain that is within the acceptable confidence interval. For AISI 4140 and AISI 1020 steels, hardness is found to have a slight decrease trend as the diameter is reduced, while an opposite behavior is observed for AA 6082 aluminum alloy. However, no definite significant behavior was noticed regarding the effect of the sector sequence (circumferential direction). PMID:28817030

Statistical and Graphical Assessment of Circumferential and Radial Hardness Variation of AISI 4140, AISI 1020 and AA 6082 Aluminum Alloy.

PubMed

Al-Khalid, Hamad; Alaskari, Ayman; Oraby, Samy

2011-12-23

Hardness homogeneity of the commonly used structural ferrous and nonferrous engineering materials is of vital importance in the design stage, therefore, reliable information regarding material properties homogeneity should be validated and any deviation should be addressed. In the current study the hardness variation, over wide spectrum radial locations of some ferrous and nonferrous structural engineering materials, was investigated. Measurements were performed over both faces (cross-section) of each stock bar according to a pre-specified stratified design, ensuring the coverage of the entire area both in radial and circumferential directions. Additionally the credibility of the apparatus and measuring procedures were examined through a statistically based calibration process of the hardness reference block. Statistical and response surface graphical analysis are used to examine the nature, adequacy and significance of the measured hardness values. Calibration of the apparatus reference block proved the reliability of the measuring system, where no strong evidence was found against the stochastic nature of hardness measures over the various stratified locations. Also, outlier elimination procedures were proved to be beneficial only at fewer measured points. Hardness measurements showed a dispersion domain that is within the acceptable confidence interval. For AISI 4140 and AISI 1020 steels, hardness is found to have a slight decrease trend as the diameter is reduced, while an opposite behavior is observed for AA 6082 aluminum alloy. However, no definite significant behavior was noticed regarding the effect of the sector sequence (circumferential direction).

Clinical and hematological data to group different chronic kidney disease patients: A practical approach to establish different groups of patients.

PubMed

Péterle, Vinícius B; Souza, Jéssica de O; Busato, Fernanda de O; Eutrópio, Frederico J; da Costa, Gisele de A P; Olivieri, David N; Tadokoro, Carlos E

2018-06-01

Chronic kidney disease (CKD) is the convergent point of several pathological processes, and its evolution is insidious and characterized by a progressive and irreversible loss of kidney function. This impaired function induces the accumulation of uremic toxins and individuals with terminal CKD often have altered physiological responses, including a persistent state of immuno-suppression and development of diseases. A better characterization and stratification of these patients with CKD in different immuno-compromised groups would contribute to more effective and personalized treatments. The focus of this study was to use two parameters to stratify patients with CKD into four separate groups that are representative of different immunological status. Patients with CKD were chosen randomly and stratified into four separate groups according to the period of time receiving dialysis treatment and leukocyte blood counts. The amount of apoptotic CD4 T cells were measured in each group of patients, and clinical/hematological parameters were correlated by multivariate analysis with each group. Observations reveal that one of the four groups of patients with CKD (group 3) had more apoptotic CD4 T cells than the other group; this group also had an increased malnutrition inflammation score (MIS), an elevated Kt/V, and a higher incidence of smoking. A simple two-parameter-based stratification strategy could be used to design effective immunological therapies that differentiate the degrees of immuno-suppression across groups of patients with CKD. © 2018 Wiley Periodicals, Inc.

Is prolonged cold ischemia a contraindication to using kidneys from acute kidney injury donors?

PubMed

Orlando, Giuseppe; Khan, Muhammad A; El-Hennawy, Hany; Farney, Alan C; Rogers, Jeffrey; Reeves-Daniel, Amber; Gautreaux, Michael D; Doares, William; Kaczmorski, Scott; Stratta, Robert J

2018-03-01

To determine the impact of prolonged cold ischemia time (CIT) on the outcome of acute kidney injury (AKI) renal grafts, we therefore performed a single-center retrospective analysis in adult patients receiving kidney transplantation (KT) from AKI donors. Outcomes were stratified according to duration of CIT. A total of 118 patients receiving AKI grafts were enrolled. Based on CIT, patients were stratified as follows: (i) <20 hours, 27 patients; (ii) 20-30 hours, 52 patients; (iii) 30-40 hours, 30 patients; (iv) ≥40 hours, nine patients. The overall incidence of delayed graft function DGF was 41.5%. According to increasing CIT category, DGF rates were 30%, 42%, 40%, and 78%, respectively (P = .03). With a mean follow-up of 48 months, overall patient and graft survival rates were 91% and 81%. Death-censored graft survival (DCGS) rates were 84% and 88% for patients with and without DGF (P = NS). DCGS rates were 92% in patients with CIT <20 hours compared to 85% with CIT >20 hours (P = NS). In the nine patients with CIT >40 hours, the 4-year DCGS rate was 100%. We conclude that prolonged CIT in AKI grafts may not adversely influence outcomes and so discard of AKI kidneys because of projected long CIT is not warranted when donors are wisely triaged. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Toward tailored disease management for type 2 diabetes.

PubMed

Elissen, Arianne M J; Duimel-Peeters, Inge G P; Spreeuwenberg, Cor; Spreeuwenberg, Marieke; Vrijhoef, Hubertus J M

2012-10-01

To assess the differentiated effects of population-based disease management programs (DMPs) for type 2 diabetes on intermediary clinical outcomes in The Netherlands. Data covering a period from 20 to 24 months between January 2008 and December 2010 were collected from 18 Dutch care groups (primary care provider networks that have bundled payment contracts for delivery of diabetes DMPs). Meta-analysis and meta-regression methods were used to conduct differentiated analyses of these programs' effects over time on 4 clinical indicators: glycated hemoglobin, lowdensity lipoprotein, systolic blood pressure, and body mass index. Heterogeneous average results were stratified according to various patient and process characteristics to investigate whether differences in these features could explain variation in outcomes. Between 56% and 71% of patients (N = 105,056) had valid first- and second-year measurements of the study outcomes. Although average changes in these measures over time were small, stratified analyses demonstrated that clinically relevant improvements were achieved in patients with poor first-year health values. Interactions with age, disease duration, comorbidity, and smoking status were not consistent across outcomes; nonetheless, heterogeneity in results decreased considerably when simultaneously correcting for known patient characteristics. Positive effects tended to diminish with longer length of follow-up, while greater measurement frequency was associated with improved results, especially in patients with poor health. Our data suggest that tailored disease management, in which not only evidencebased guidelines but also patient characteristics directly determine care processes, including self-management support, has great potential to improve the cost-effectiveness of current chronic care delivery.

Partial Wave Analysis of Coupled Photonic Structures

NASA Technical Reports Server (NTRS)

Fuller, Kirk A.; Smith, David D.; Curreri, Peter A. (Technical Monitor)

2002-01-01

The very high quality factors sustained by microcavity optical resonators are relevant to applications in wavelength filtering, routing, switching, modulation, and multiplexing/demultiplexing. Increases in the density of photonic elements require that attention be paid to how electromagnetic (EM) coupling modifies their optical properties. This is especially true when cavity resonances are involved, in which case, their characteristics may be fundamentally altered. Understanding the optical properties of microcavities that are near or in contact with photonic elements---such as other microcavities, nanostructures, couplers, and substrates---can be expected to advance our understanding of the roles that these structures may play in VLSI photonics, biosensors and similar device technologies. Wc present results from recent theoretical studies of the effects of inter- and intracavity coupling on optical resonances in compound spherical particles. Concentrically stratified spheres and bispheres constituted from homogeneous and stratified spheres are subjects of this investigation. A new formulation is introduced for the absorption of light in an arbitrary layer of a multilayered sphere, which is based on multiple reflections of the spherical partial waves of the Lorenz-Mie solution for scattering by a sphere. Absorption efficiencies, which can be used to profile cavity resonances and to infer fluorescence yields or the onset of nonlinear optical processes in the microcavities, are presented. Splitting of resonances in these multisphere systems is paid particular attention, and consequences for photonic device development and possible performance enhancements through carefully designed architectures that exploit EM coupling are considered.

In the Aftermath of Act 10: The Changed State of Teaching in a Changed State

ERIC Educational Resources Information Center

Swalwell, Katy; Schweber, Simone; Sinclair, Kristin; Gallagher, Jennifer; Schirmer, Eleni

2017-01-01

Act 10, the 2011 legislative ruling in Wisconsin that reduced public-sector unions' collective bargaining power, provides a descriptive case study to examine what happens to teachers when collective bargaining disappears. Analysis of interviews with social studies teachers (n = 26) from a stratified random sample of 13 districts shows that the…

Response of the Elderly to Disaster: An Age-Stratified Analysis.

ERIC Educational Resources Information Center

Bolin, Robert; Klenow, Daniel J.

1982-01-01

Analyzed the effect of age on elderly tornado victims' (N=62) responses to stress effects. Compared to younger victims (N=240), the elderly did not suffer disproportionate material losses, but were more likely to be injured and have a death in the household. Elderly victims had a lower incidene of emotional and family problems. (Author/JAC)

Classroom Questioning Tendencies from the Perspective of Big Data

ERIC Educational Resources Information Center

Lu, Wang; Rongxiao, Cai

2016-01-01

We are now living in an era of big data. From the perspective of data analysis of classroom questioning, the paper chooses three districts in City B that have significant differences. These are educationally developed District D, less developed District F, and developing District M. The study uses the stratified sampling method to choose from…

Unmet Dental Needs and Barriers to Dental Care among Children with Autism Spectrum Disorders

ERIC Educational Resources Information Center

Lai, Bien; Milano, Michael; Roberts, Michael W.; Hooper, Stephen R.

2012-01-01

Mail-in pilot-tested questionnaires were sent to a stratified random sample of 1,500 families from the North Carolina Autism Registry. Multivariate logistic regression analysis was used to determine the significance of unmet dental needs and other predictors. Of 568 surveys returned (Response Rate = 38%), 555 were complete and usable. Sixty-five…

The Development and Validation of a Mechanical Critical Thinking Scale for High School Students

ERIC Educational Resources Information Center

Yu, Kuang-Chao; Lin, Kuen-Yi; Chang, Shu-Fen

2017-01-01

The purpose of this study was to develop a mechanical critical thinking scale for high school students. A stratified random sampling method was used to establish the norms. After pre-tests and item analysis, the scale was determined to have five subtest sections (i.e., recognition of assumptions, induction, deduction, interpretation, and…