A meta-analysis of in vitro antibiotic synergy against Acinetobacter baumannii.

PubMed

March, Gabriel A; Bratos, Miguel A

2015-12-01

The aim of the work was to describe the different in vitro models for testing synergism of antibiotics and gather the results of antibiotic synergy against multidrug-resistant Acinetobacter baumannii (MDR-Ab). The different original articles were obtained from different web sites. In order to compare the results obtained by the different methods for synergy testing, the Pearson chi-square and the Fischer tests were used. Moreover, non-parametric chi-square test was used in order to compare the frequency distribution in each analysed manuscript. In the current meta-analysis 24 manuscripts, which encompassed 2016 tests of in vitro synergism of different antimicrobials against MDR-Ab, were revised. Checkerboard synergy testing was used in 11 studies, which encompasses 1086 tests (53.9%); time-kill assays were applied in 12 studies, which encompass 359 tests (17.8%); gradient diffusion methods were used in seven studies, encompassing 293 tests (14.5%). And, finally, time-kill plus checkerboard were applied in two studies, encompassing 278 tests (13.8%). By comparing these data, checkerboard and time-kill methods were significantly more used than gradient diffusion methods (p<0.005). Regarding synergy rates obtained on the basis of the applied method, checkerboard provided 227 tests (20.9%) with a synergistic effect; time-kill assays yielded 222 tests (61.8%) with a synergistic effect; gradient diffusion methods only provided 29 tests (9.9%) with a synergistic effect; and, finally, time-kill plus checkerboard yielded just 15 tests (5.4%) with a synergistic effect. When comparing these percentages, synergy rates reported by time-kill methods were significantly higher than that obtained by checkerboard and gradient diffusion methods (p<0.005). On the basis of the revised data, the combinations of a bactericidal antibiotic plus Tigecycline, Vancomycin or Teicoplanin are not recommended. The best combinations of antibiotics are those which include bactericidal antibiotics such as Carbapenems, Fosfomycin, Amikacin, Polymyxins, Rifampicin and Ampicillin/Sulbactam. Copyright © 2015. Published by Elsevier B.V.

Automated Dissolution for Enteric-Coated Aspirin Tablets: A Case Study for Method Transfer to a RoboDis II.

PubMed

Ibrahim, Sarah A; Martini, Luigi

2014-08-01

Dissolution method transfer is a complicated yet common process in the pharmaceutical industry. With increased pharmaceutical product manufacturing and dissolution acceptance requirements, dissolution testing has become one of the most labor-intensive quality control testing methods. There is an increased trend for automation in dissolution testing, particularly for large pharmaceutical companies to reduce variability and increase personnel efficiency. There is no official guideline for dissolution testing method transfer from a manual, semi-automated, to automated dissolution tester. In this study, a manual multipoint dissolution testing procedure for an enteric-coated aspirin tablet was transferred effectively and reproducibly to a fully automated dissolution testing device, RoboDis II. Enteric-coated aspirin samples were used as a model formulation to assess the feasibility and accuracy of media pH change during continuous automated dissolution testing. Several RoboDis II parameters were evaluated to ensure the integrity and equivalency of dissolution method transfer from a manual dissolution tester. This current study provides a systematic outline for the transfer of the manual dissolution testing protocol to an automated dissolution tester. This study further supports that automated dissolution testers compliant with regulatory requirements and similar to manual dissolution testers facilitate method transfer. © 2014 Society for Laboratory Automation and Screening.

Research design and statistical methods in Pakistan Journal of Medical Sciences (PJMS).

PubMed

Akhtar, Sohail; Shah, Syed Wadood Ali; Rafiq, M; Khan, Ajmal

2016-01-01

This article compares the study design and statistical methods used in 2005, 2010 and 2015 of Pakistan Journal of Medical Sciences (PJMS). Only original articles of PJMS were considered for the analysis. The articles were carefully reviewed for statistical methods and designs, and then recorded accordingly. The frequency of each statistical method and research design was estimated and compared with previous years. A total of 429 articles were evaluated (n=74 in 2005, n=179 in 2010, n=176 in 2015) in which 171 (40%) were cross-sectional and 116 (27%) were prospective study designs. A verity of statistical methods were found in the analysis. The most frequent methods include: descriptive statistics (n=315, 73.4%), chi-square/Fisher's exact tests (n=205, 47.8%) and student t-test (n=186, 43.4%). There was a significant increase in the use of statistical methods over time period: t-test, chi-square/Fisher's exact test, logistic regression, epidemiological statistics, and non-parametric tests. This study shows that a diverse variety of statistical methods have been used in the research articles of PJMS and frequency improved from 2005 to 2015. However, descriptive statistics was the most frequent method of statistical analysis in the published articles while cross-sectional study design was common study design.

Four applications of permutation methods to testing a single-mediator model.

PubMed

Taylor, Aaron B; MacKinnon, David P

2012-09-01

Four applications of permutation tests to the single-mediator model are described and evaluated in this study. Permutation tests work by rearranging data in many possible ways in order to estimate the sampling distribution for the test statistic. The four applications to mediation evaluated here are the permutation test of ab, the permutation joint significance test, and the noniterative and iterative permutation confidence intervals for ab. A Monte Carlo simulation study was used to compare these four tests with the four best available tests for mediation found in previous research: the joint significance test, the distribution of the product test, and the percentile and bias-corrected bootstrap tests. We compared the different methods on Type I error, power, and confidence interval coverage. The noniterative permutation confidence interval for ab was the best performer among the new methods. It successfully controlled Type I error, had power nearly as good as the most powerful existing methods, and had better coverage than any existing method. The iterative permutation confidence interval for ab had lower power than do some existing methods, but it performed better than any other method in terms of coverage. The permutation confidence interval methods are recommended when estimating a confidence interval is a primary concern. SPSS and SAS macros that estimate these confidence intervals are provided.

On sample size of the kruskal-wallis test with application to a mouse peritoneal cavity study.

PubMed

Fan, Chunpeng; Zhang, Donghui; Zhang, Cun-Hui

2011-03-01

As the nonparametric generalization of the one-way analysis of variance model, the Kruskal-Wallis test applies when the goal is to test the difference between multiple samples and the underlying population distributions are nonnormal or unknown. Although the Kruskal-Wallis test has been widely used for data analysis, power and sample size methods for this test have been investigated to a much lesser extent. This article proposes new power and sample size calculation methods for the Kruskal-Wallis test based on the pilot study in either a completely nonparametric model or a semiparametric location model. No assumption is made on the shape of the underlying population distributions. Simulation results show that, in terms of sample size calculation for the Kruskal-Wallis test, the proposed methods are more reliable and preferable to some more traditional methods. A mouse peritoneal cavity study is used to demonstrate the application of the methods. © 2010, The International Biometric Society.

Do Examinees Understand Score Reports for Alternate Methods of Scoring Computer Based Tests?

ERIC Educational Resources Information Center

Whittaker, Tiffany A.; Williams, Natasha J.; Dodd, Barbara G.

2011-01-01

This study assessed the interpretability of scaled scores based on either number correct (NC) scoring for a paper-and-pencil test or one of two methods of scoring computer-based tests: an item pattern (IP) scoring method and a method based on equated NC scoring. The equated NC scoring method for computer-based tests was proposed as an alternative…

Equating Scores from Adaptive to Linear Tests

ERIC Educational Resources Information Center

van der Linden, Wim J.

2006-01-01

Two local methods for observed-score equating are applied to the problem of equating an adaptive test to a linear test. In an empirical study, the methods were evaluated against a method based on the test characteristic function (TCF) of the linear test and traditional equipercentile equating applied to the ability estimates on the adaptive test…

Desensitization And Study-Skills Training As Treatment For Two Types of Test-Anxious Students

ERIC Educational Resources Information Center

Osterhouse, Robert A.

1972-01-01

This study compared the effectiveness of systematic desensitization and training in efficient study methods for reducing test anxiety among subjects selected on the basis of two types of self reported anxiety. Desensitization offered more promise as a treatment method for test anxiety than did training in study skills. (Author)

A comparative study of biodegradability of a carcinogenic aromatic amine (4,4'-diaminodiphenylmethane) with OECD 301 test methods.

PubMed

Mei, Cheng-Fang; Liu, Yan-Zhen; Long, Wei-Nian; Sun, Guo-Ping; Zeng, Guo-Qu; Xu, Mei-Ying; Luan, Tian-Gang

2015-01-01

4,4'-Diaminodiphenylmethane (MDA) is a widely used compound in industries. Studies on the biodegradability of MDA are necessary for environmental hazard identification and risk assessment. Previous studies have suggested that MDA was not readily biodegradable. In the present study, three batches of biodegradation tests (OECD 301A, B, D and F tests) were performed on MDA in June, August and December of 2012. MDA was found to be readily biodegradable and produced colored intermediates in the 301A, B and F test systems. MDA biodegradation measurements were consistent among the three batches of tests. Differences in the extent of biodegradation determined in different methods originated from different test conditions and assessment endpoints. The 301D test has stringent test conditions and is usually performed on chemicals that are toxic to microorganisms, so the test results obtained from 301D tests are less meaningful for evaluating the biodegradability of MDA. The low MDA biodegradation measurements in the 301B tests compared to the 301A and F tests were due to the assessment method, which did not account for MDA incorporation into biomass in its calculation of CO2 formation rate. The differences in the biodegradation rates, as measured by the different OECD 301 test systems, could also be related to the structure and properties of the chemical. For test substances that can be assessed by all OECD 301 test methods, the highest biodegradation values may be obtained from the 301A and F test methods. This study provides new information to assess the environmental fate in the risk assessment of MDA. Copyright © 2014 Elsevier Inc. All rights reserved.

Study of methods of improving the performance of the Langley Research Center Transonic Dynamics Tunnel (TDT)

NASA Technical Reports Server (NTRS)

1973-01-01

A study has been made of possible ways to improve the performance of the Langley Research Center's Transonic Dynamics Tunnel (TDT). The major effort was directed toward obtaining increased dynamic pressure in the Mach number range from 0.8 to 1.2, but methods to increase Mach number capability were also considered. Methods studied for increasing dynamic pressure capability were higher total pressure, auxiliary suction, reducing circuit losses, reduced test medium temperature, smaller test section and higher molecular weight test medium. Increased Mach number methods investigated were nozzle block inserts, variable geometry nozzle, changes in test section wall configuration, and auxiliary suction.

Study on the system-level test method of digital metering in smart substation

NASA Astrophysics Data System (ADS)

Zhang, Xiang; Yang, Min; Hu, Juan; Li, Fuchao; Luo, Ruixi; Li, Jinsong; Ai, Bing

2017-03-01

Nowadays, the test methods of digital metering system in smart substation are used to test and evaluate the performance of a single device, but these methods can only effectively guarantee the accuracy and reliability of the measurement results of a digital metering device in a single run, it does not completely reflect the performance when each device constitutes a complete system. This paper introduced the shortages of the existing test methods. A system-level test method of digital metering in smart substation was proposed, and the feasibility of the method was proved by the actual test.

Development of a nondestructive leak testing method utilizing the head space analyzer for ampoule products containing ethanol-based solutions.

PubMed

Sudo, Hirotaka; O'driscoll, Michael; Nishiwaki, Kenji; Kawamoto, Yuji; Gammell, Philip; Schramm, Gerhard; Wertli, Toni; Prinz, Heino; Mori, Atsuhide; Sako, Kazuhiro

2012-01-01

The application of a head space analyzer for oxygen concentration was examined to develop a novel ampoule leak test method. Studies using ampoules filled with ethanol-based solution and with nitrogen in the headspace demonstrated that the head space analysis (HSA) method showed sufficient sensitivity in detecting an ampoule crack. The proposed method is the use of HSA in conjunction with the pretreatment of an overpressurising process known as bombing to facilitate the oxygen flow through the crack in the ampoule. The method was examined in comparative studies with a conventional dye ingress method, and the results showed that the HSA method exhibits sensitivity superior to the dye method. The results indicate that the HSA method in combination with the bombing treatment provides potential application as a leak test for the detection of container defects not only for ampoule products with ethanol-based solutions, but also for testing lyophilized products in vials with nitrogen in the head space. The application of a head space analyzer for oxygen concentration was examined to develop a novel ampoule leak test method. The proposed method is the use of head space analysis (HSA) in conjunction with the pretreatment of an overpressurising process known as bombing to facilitate oxygen flow through the crack in the ampoule for use in routine production. The result of the comparative study with a conventional dye leak test method indicates that the HSA method in combination with the bombing treatment can be used as a leak test method, enabling detection of container defects.

Research design and statistical methods in Pakistan Journal of Medical Sciences (PJMS)

PubMed Central

Akhtar, Sohail; Shah, Syed Wadood Ali; Rafiq, M.; Khan, Ajmal

2016-01-01

Objective: This article compares the study design and statistical methods used in 2005, 2010 and 2015 of Pakistan Journal of Medical Sciences (PJMS). Methods: Only original articles of PJMS were considered for the analysis. The articles were carefully reviewed for statistical methods and designs, and then recorded accordingly. The frequency of each statistical method and research design was estimated and compared with previous years. Results: A total of 429 articles were evaluated (n=74 in 2005, n=179 in 2010, n=176 in 2015) in which 171 (40%) were cross-sectional and 116 (27%) were prospective study designs. A verity of statistical methods were found in the analysis. The most frequent methods include: descriptive statistics (n=315, 73.4%), chi-square/Fisher’s exact tests (n=205, 47.8%) and student t-test (n=186, 43.4%). There was a significant increase in the use of statistical methods over time period: t-test, chi-square/Fisher’s exact test, logistic regression, epidemiological statistics, and non-parametric tests. Conclusion: This study shows that a diverse variety of statistical methods have been used in the research articles of PJMS and frequency improved from 2005 to 2015. However, descriptive statistics was the most frequent method of statistical analysis in the published articles while cross-sectional study design was common study design. PMID:27022365

TEST METHODS TO DETERMINE THE MERCURY EMISSIONS FROM SLUDGE INCINERATION PLANTS

EPA Science Inventory

Two test methods for mercury are described along with the laboratory and field studies done in developing and validating them. One method describes how to homogenize and analyze large quantities of sewage sludge. The other test method describes how to measure the mercury emission...

Investigating Item Exposure Control Methods in Computerized Adaptive Testing

ERIC Educational Resources Information Center

Ozturk, Nagihan Boztunc; Dogan, Nuri

2015-01-01

This study aims to investigate the effects of item exposure control methods on measurement precision and on test security under various item selection methods and item pool characteristics. In this study, the Randomesque (with item group sizes of 5 and 10), Sympson-Hetter, and Fade-Away methods were used as item exposure control methods. Moreover,…

Comparison of 3 in vivo methods for assessment of alcohol-based hand rubs.

PubMed

Edmonds-Wilson, Sarah; Campbell, Esther; Fox, Kyle; Macinga, David

2015-05-01

Alcohol-based hand rubs (ABHRs) are the primary method of hand hygiene in health-care settings. ICPs increasingly are assessing ABHR product efficacy data as improved products and test methods are developed. As a result, ICPs need better tools and recommendations for how to assess and compare ABHRs. Two ABHRs (70% ethanol) were tested according to 3 in vivo methods approved by ASTM International: E1174, E2755, and E2784. Log10 reductions were measured after a single test product use and after 10 consecutive uses at an application volume of 2 mL. The test method used had a significant influence on ABHR efficacy; however, in this study the test product (gel or foam) did not significantly influence efficacy. In addition, for all test methods, log10 reductions obtained after a single application were not predictive of results after 10 applications. Choice of test method can significantly influence efficacy results. Therefore, when assessing antimicrobial efficacy data of hand hygiene products, ICPs should pay close attention to the test method used, and ensure that product comparisons are made head to head in the same study using the same test methodology. Copyright © 2015 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

Variance Difference between Maximum Likelihood Estimation Method and Expected A Posteriori Estimation Method Viewed from Number of Test Items

ERIC Educational Resources Information Center

Mahmud, Jumailiyah; Sutikno, Muzayanah; Naga, Dali S.

2016-01-01

The aim of this study is to determine variance difference between maximum likelihood and expected A posteriori estimation methods viewed from number of test items of aptitude test. The variance presents an accuracy generated by both maximum likelihood and Bayes estimation methods. The test consists of three subtests, each with 40 multiple-choice…

General Framework for Meta-analysis of Rare Variants in Sequencing Association Studies

PubMed Central

Lee, Seunggeun; Teslovich, Tanya M.; Boehnke, Michael; Lin, Xihong

2013-01-01

We propose a general statistical framework for meta-analysis of gene- or region-based multimarker rare variant association tests in sequencing association studies. In genome-wide association studies, single-marker meta-analysis has been widely used to increase statistical power by combining results via regression coefficients and standard errors from different studies. In analysis of rare variants in sequencing studies, region-based multimarker tests are often used to increase power. We propose meta-analysis methods for commonly used gene- or region-based rare variants tests, such as burden tests and variance component tests. Because estimation of regression coefficients of individual rare variants is often unstable or not feasible, the proposed method avoids this difficulty by calculating score statistics instead that only require fitting the null model for each study and then aggregating these score statistics across studies. Our proposed meta-analysis rare variant association tests are conducted based on study-specific summary statistics, specifically score statistics for each variant and between-variant covariance-type (linkage disequilibrium) relationship statistics for each gene or region. The proposed methods are able to incorporate different levels of heterogeneity of genetic effects across studies and are applicable to meta-analysis of multiple ancestry groups. We show that the proposed methods are essentially as powerful as joint analysis by directly pooling individual level genotype data. We conduct extensive simulations to evaluate the performance of our methods by varying levels of heterogeneity across studies, and we apply the proposed methods to meta-analysis of rare variant effects in a multicohort study of the genetics of blood lipid levels. PMID:23768515

Multiple testing and power calculations in genetic association studies.

PubMed

So, Hon-Cheong; Sham, Pak C

2011-01-01

Modern genetic association studies typically involve multiple single-nucleotide polymorphisms (SNPs) and/or multiple genes. With the development of high-throughput genotyping technologies and the reduction in genotyping cost, investigators can now assay up to a million SNPs for direct or indirect association with disease phenotypes. In addition, some studies involve multiple disease or related phenotypes and use multiple methods of statistical analysis. The combination of multiple genetic loci, multiple phenotypes, and multiple methods of evaluating associations between genotype and phenotype means that modern genetic studies often involve the testing of an enormous number of hypotheses. When multiple hypothesis tests are performed in a study, there is a risk of inflation of the type I error rate (i.e., the chance of falsely claiming an association when there is none). Several methods for multiple-testing correction are in popular use, and they all have strengths and weaknesses. Because no single method is universally adopted or always appropriate, it is important to understand the principles, strengths, and weaknesses of the methods so that they can be applied appropriately in practice. In this article, we review the three principle methods for multiple-testing correction and provide guidance for calculating statistical power.

Tube and column agglutination technology for autocontrol testing.

PubMed

Courtney, J E; Vincent, J L; Indrikovs, A J

2001-01-01

The incidence of positive autocontrol test results with column agglutination technology is a concern. This study investigates the incidence and significance of positive autocontrols in the ID Micro Typing System (gel) and the Gamma ReACT (ReACT). The study encompassed a total of 1021 randomly selected samples from patients and 95 samples from donors collected during 1 month. The autocontrol testing was carried out according to the manufacturer's instructions for the column agglutination tests. The tube method was carried out using low-ionic-strength solution (LISS). The direct antiglobulin test (DAT) was performed using the tube method, and further investigated with elution studies if warranted. Seventy-nine patient's samples (7.74%) had a positive autocontrol: the gel test, 72 (91.13%); ReACT, 21 (26.58%); and the tube method, 27 (34.18%). Of the 79 positive autocontrols, 44 samples had a negative DAT. Of the samples with positive DAT results, only one possessed a clinically significant antibody, anti-D. Moreover, the same sample also tested positive in all three methods. Column agglutination techniques have increased sensitivity for a positive autocontrol beyond the conventional tube method. However, ReACT and gel tests differ significantly in their frequency of positives. Investigation of the significance of a positive autocontrol in column agglutination technology when the conventional tube method is also positive is suggested.

A study of short test and charge retention test methods for nickel-cadmium spacecraft cells

NASA Technical Reports Server (NTRS)

Scott, W. R.

1975-01-01

Methods for testing nickel-cadmium cells for internal shorts and charge retention were studied. Included were (a) open circuit voltage decay after a brief charge, (b) open circuit voltage recovery after shorting, and (c) open circuit voltage decay and capacity loss after a full charge. The investigation included consideration of the effects of prior history, of conditioning cells prior to testing, and of various test method variables on the results of the tests. Sensitivity of the tests was calibrated in terms of equivalent external resistance. The results were correlated. It was shown that a large number of variables may affect the results of these tests. It is concluded that the voltage decay after a brief charge and the voltage recovery methods are more sensitive than the charged stand method, and can detect an internal short equivalent to a resistance of about (10,000/C)ohms where "C' is the numerical value of the capacity of the cell in ampere hours.

Some important considerations in the development of stress corrosion cracking test methods.

NASA Technical Reports Server (NTRS)

Wei, R. P.; Novak, S. R.; Williams, D. P.

1972-01-01

Discussion of some of the precaution needs the development of fracture-mechanics based test methods for studying stress corrosion cracking involves. Following a review of pertinent analytical fracture mechanics considerations and of basic test methods, the implications for test corrosion cracking studies of the time-to-failure determining kinetics of crack growth and life are examined. It is shown that the basic assumption of the linear-elastic fracture mechanics analyses must be clearly recognized and satisfied in experimentation and that the effects of incubation and nonsteady-state crack growth must also be properly taken into account in determining the crack growth kinetics, if valid data are to be obtained from fracture-mechanics based test methods.

Method modification of the Legipid® Legionella fast detection test kit.

PubMed

Albalat, Guillermo Rodríguez; Broch, Begoña Bedrina; Bono, Marisa Jiménez

2014-01-01

Legipid(®) Legionella Fast Detection is a test based on combined magnetic immunocapture and enzyme-immunoassay (CEIA) for the detection of Legionella in water. The test is based on the use of anti-Legionella antibodies immobilized on magnetic microspheres. Target microorganism is preconcentrated by filtration. Immunomagnetic analysis is applied on these preconcentrated water samples in a final test portion of 9 mL. The test kit was certified by the AOAC Research Institute as Performance Tested Method(SM) (PTM) No. 111101 in a PTM validation which certifies the performance claims of the test method in comparison to the ISO reference method 11731-1998 and the revision 11731-2004 "Water Quality: Detection and Enumeration of Legionella pneumophila" in potable water, industrial water, and waste water. The modification of this test kit has been approved. The modification includes increasing the target analyte from L. pneumophila to Legionella species and adding an optical reader to the test method. In this study, 71 strains of Legionella spp. other than L. pneumophila were tested to determine its reactivity with the kit based on CEIA. All the strains of Legionella spp. tested by the CEIA test were confirmed positive by reference standard method ISO 11731. This test (PTM 111101) has been modified to include a final optical reading. A methods comparison study was conducted to demonstrate the equivalence of this modification to the reference culture method. Two water matrixes were analyzed. Results show no statistically detectable difference between the test method and the reference culture method for the enumeration of Legionella spp. The relative level of detection was 93 CFU/volume examined (LOD50). For optical reading, the LOD was 40 CFU/volume examined and the LOQ was 60 CFU/volume examined. Results showed that the test Legipid Legionella Fast Detection is equivalent to the reference culture method for the enumeration of Legionella spp.

A prevalence-based association test for case-control studies.

PubMed

Ryckman, Kelli K; Jiang, Lan; Li, Chun; Bartlett, Jacquelaine; Haines, Jonathan L; Williams, Scott M

2008-11-01

Genetic association is often determined in case-control studies by the differential distribution of alleles or genotypes. Recent work has demonstrated that association can also be assessed by deviations from the expected distributions of alleles or genotypes. Specifically, multiple methods motivated by the principles of Hardy-Weinberg equilibrium (HWE) have been developed. However, these methods do not take into account many of the assumptions of HWE. Therefore, we have developed a prevalence-based association test (PRAT) as an alternative method for detecting association in case-control studies. This method, also motivated by the principles of HWE, uses an estimated population allele frequency to generate expected genotype frequencies instead of using the case and control frequencies separately. Our method often has greater power, under a wide variety of genetic models, to detect association than genotypic, allelic or Cochran-Armitage trend association tests. Therefore, we propose PRAT as a powerful alternative method of testing for association.

Nondestructive equipment study

NASA Technical Reports Server (NTRS)

1985-01-01

Identification of existing nondestructive Evaluation (NDE) methods that could be used in a low Earth orbit environment; evaluation of each method with respect to the set of criteria called out in the statement of work; selection of the most promising NDE methods for further evaluation; use of selected NDE methods to test samples of pressure vessel materials in a vacuum; pressure testing of a complex monolythic pressure vessel with known flaws using acoustic emissions in a vacuum; and recommendations for further studies based on analysis and testing are covered.

A Residual Mass Ballistic Testing Method to Compare Armor Materials or Components (Residual Mass Ballistic Testing Method)

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

Benjamin Langhorst; Thomas M Lillo; Henry S Chu

2014-05-01

A statistics based ballistic test method is presented for use when comparing multiple groups of test articles of unknown relative ballistic perforation resistance. The method is intended to be more efficient than many traditional methods for research and development testing. To establish the validity of the method, it is employed in this study to compare test groups of known relative ballistic performance. Multiple groups of test articles were perforated using consistent projectiles and impact conditions. Test groups were made of rolled homogeneous armor (RHA) plates and differed in thickness. After perforation, each residual projectile was captured behind the target andmore » its mass was measured. The residual masses measured for each test group were analyzed to provide ballistic performance rankings with associated confidence levels. When compared to traditional V50 methods, the residual mass (RM) method was found to require fewer test events and be more tolerant of variations in impact conditions.« less

[Application of Stata software to test heterogeneity in meta-analysis method].

PubMed

Wang, Dan; Mou, Zhen-yun; Zhai, Jun-xia; Zong, Hong-xia; Zhao, Xiao-dong

2008-07-01

To introduce the application of Stata software to heterogeneity test in meta-analysis. A data set was set up according to the example in the study, and the corresponding commands of the methods in Stata 9 software were applied to test the example. The methods used were Q-test and I2 statistic attached to the fixed effect model forest plot, H statistic and Galbraith plot. The existence of the heterogeneity among studies could be detected by Q-test and H statistic and the degree of the heterogeneity could be detected by I2 statistic. The outliers which were the sources of the heterogeneity could be spotted from the Galbraith plot. Heterogeneity test in meta-analysis can be completed by the four methods in Stata software simply and quickly. H and I2 statistics are more robust, and the outliers of the heterogeneity can be clearly seen in the Galbraith plot among the four methods.

Oral acute toxic class method: a successful alternative to the oral LD50 test.

PubMed

Schlede, Eva; Genschow, Elke; Spielmann, Horst; Stropp, Gisela; Kayser, Detlev

2005-06-01

The oral acute toxic class method (ATC method) was developed as an alternative to replace the oral LD50 test. The ATC method is a sequential testing procedure using only three animals of one sex per step at any of the defined dose levels. Depending on the mortality rate three but never more than six animals are used per dose level. This approach results in the reduction of numbers of animals used in comparison to the LD50 test by 40-70%. The principle of the oral ATC method is based on the Probit model and it was first evaluated on a biometric basis before a national and subsequently an international ring study were conducted. The results demonstrated an excellent agreement between the toxicity and the animal numbers predicted biometrically and observed in the validation studies. The oral ATC method was adopted as an official test guideline by OECD in 1996 and was slightly amended in 2001. The ATC method has been successfully used in Germany and in 2003 >85% of all tests on acute oral toxicity testing was conducted as oral ATC tests. In member states of the European Union the ATC method is used in the range of 50% of all tests conducted. Meanwhile the oral LD50 test has been deleted by OECD, by the European Union and by the USA, making the use of alternatives to the oral LD50 test mandatory.

Rapid and Accurate Multiple Testing Correction and Power Estimation for Millions of Correlated Markers

PubMed Central

Han, Buhm; Kang, Hyun Min; Eskin, Eleazar

2009-01-01

With the development of high-throughput sequencing and genotyping technologies, the number of markers collected in genetic association studies is growing rapidly, increasing the importance of methods for correcting for multiple hypothesis testing. The permutation test is widely considered the gold standard for accurate multiple testing correction, but it is often computationally impractical for these large datasets. Recently, several studies proposed efficient alternative approaches to the permutation test based on the multivariate normal distribution (MVN). However, they cannot accurately correct for multiple testing in genome-wide association studies for two reasons. First, these methods require partitioning of the genome into many disjoint blocks and ignore all correlations between markers from different blocks. Second, the true null distribution of the test statistic often fails to follow the asymptotic distribution at the tails of the distribution. We propose an accurate and efficient method for multiple testing correction in genome-wide association studies—SLIDE. Our method accounts for all correlation within a sliding window and corrects for the departure of the true null distribution of the statistic from the asymptotic distribution. In simulations using the Wellcome Trust Case Control Consortium data, the error rate of SLIDE's corrected p-values is more than 20 times smaller than the error rate of the previous MVN-based methods' corrected p-values, while SLIDE is orders of magnitude faster than the permutation test and other competing methods. We also extend the MVN framework to the problem of estimating the statistical power of an association study with correlated markers and propose an efficient and accurate power estimation method SLIP. SLIP and SLIDE are available at http://slide.cs.ucla.edu. PMID:19381255

[Research progress on mechanical performance evaluation of artificial intervertebral disc].

PubMed

Li, Rui; Wang, Song; Liao, Zhenhua; Liu, Weiqiang

2018-03-01

The mechanical properties of artificial intervertebral disc (AID) are related to long-term reliability of prosthesis. There are three testing methods involved in the mechanical performance evaluation of AID based on different tools: the testing method using mechanical simulator, in vitro specimen testing method and finite element analysis method. In this study, the testing standard, testing equipment and materials of AID were firstly introduced. Then, the present status of AID static mechanical properties test (static axial compression, static axial compression-shear), dynamic mechanical properties test (dynamic axial compression, dynamic axial compression-shear), creep and stress relaxation test, device pushout test, core pushout test, subsidence test, etc. were focused on. The experimental techniques using in vitro specimen testing method and testing results of available artificial discs were summarized. The experimental methods and research status of finite element analysis were also summarized. Finally, the research trends of AID mechanical performance evaluation were forecasted. The simulator, load, dynamic cycle, motion mode, specimen and test standard would be important research fields in the future.

[Interlaboratory Study on Evaporation Residue Test for Food Contact Products (Report 2)].

PubMed

Ohno, Hiroyuki; Mutsuga, Motoh; Abe, Tomoyuki; Abe, Yutaka; Amano, Homare; Ishihara, Kinuyo; Ohsaka, Ikue; Ohno, Haruka; Ohno, Yuichiro; Ozaki, Asako; Kakihara, Yoshiteru; Kobayashi, Hisashi; Sakuragi, Hiroshi; Shibata, Hiroshi; Shirono, Katsuhiro; Sekido, Haruko; Takasaka, Noriko; Takenaka, Yu; Tajima, Yoshiyasu; Tanaka, Aoi; Tanaka, Hideyuki; Nakanishi, Toru; Nomura, Chie; Haneishi, Nahoko; Hayakawa, Masato; Miura, Toshihiko; Yamaguchi, Miku; Yamada, Kyohei; Watanabe, Kazunari; Sato, Kyoko

2018-01-01

An interlaboratory study was performed to evaluate the equivalence between an official method and a modified method of evaporation residue test using heptane as a food-simulating solvent for oily or fatty foods, based on the Japanese Food Sanitation Law for food contact products. Twenty-three laboratories participated, and tested the evaporation residues of nine test solutions as blind duplicates. In the official method, heating for evaporation was done with a water bath. In the modified method, a hot plate was used for evaporation, and/or a vacuum concentration procedure was skipped. In most laboratories, the test solutions were heated until just prior to dryness, and then allowed to dry under residual heat. Statistical analysis revealed that there was no significant difference between the two methods. Accordingly, the modified method provides performance equal to the official method, and is available as an alternative method. Furthermore, an interlaboratory study was performed to evaluate and compare two leaching solutions (95% ethanol and isooctane) used as food-simulating solvents for oily or fatty foods in the EU. The results demonstrated that there was no significant difference between heptane and these two leaching solutions.

Practicing Accounting Profession Criterial Skills in the Classroom: A Study of Collaborative Testing and the Impact on Final Exam Scores

ERIC Educational Resources Information Center

VanderLaan, Ski R.

2010-01-01

This mixed methods study (Creswell, 2008) was designed to test the influence of collaborative testing on learning using a quasi-experimental approach. This study used a modified embedded mixed method design in which the qualitative and quantitative data, associated with the secondary questions, provided a supportive role in a study based primarily…

Historical Development of Asphalt Content Determination by the Ignition Method

DOT National Transportation Integrated Search

1996-01-01

This study was conducted to develop a reliable, detailed test procedure for determining asphalt cement (AC) content by the ignition method. The goal was to minimize the overall test time as well as technician time, and to produce a test method with a...

Standardization of Laboratory Methods for the PERCH Study

PubMed Central

Karron, Ruth A.; Morpeth, Susan C.; Bhat, Niranjan; Levine, Orin S.; Baggett, Henry C.; Brooks, W. Abdullah; Feikin, Daniel R.; Hammitt, Laura L.; Howie, Stephen R. C.; Knoll, Maria Deloria; Kotloff, Karen L.; Madhi, Shabir A.; Scott, J. Anthony G.; Thea, Donald M.; Adrian, Peter V.; Ahmed, Dilruba; Alam, Muntasir; Anderson, Trevor P.; Antonio, Martin; Baillie, Vicky L.; Dione, Michel; Endtz, Hubert P.; Gitahi, Caroline; Karani, Angela; Kwenda, Geoffrey; Maiga, Abdoul Aziz; McClellan, Jessica; Mitchell, Joanne L.; Morailane, Palesa; Mugo, Daisy; Mwaba, John; Mwansa, James; Mwarumba, Salim; Nyongesa, Sammy; Panchalingam, Sandra; Rahman, Mustafizur; Sawatwong, Pongpun; Tamboura, Boubou; Toure, Aliou; Whistler, Toni; O’Brien, Katherine L.; Murdoch, David R.

2017-01-01

Abstract The Pneumonia Etiology Research for Child Health study was conducted across 7 diverse research sites and relied on standardized clinical and laboratory methods for the accurate and meaningful interpretation of pneumonia etiology data. Blood, respiratory specimens, and urine were collected from children aged 1–59 months hospitalized with severe or very severe pneumonia and community controls of the same age without severe pneumonia and were tested with an extensive array of laboratory diagnostic tests. A standardized testing algorithm and standard operating procedures were applied across all study sites. Site laboratories received uniform training, equipment, and reagents for core testing methods. Standardization was further assured by routine teleconferences, in-person meetings, site monitoring visits, and internal and external quality assurance testing. Targeted confirmatory testing and testing by specialized assays were done at a central reference laboratory. PMID:28575358

Outcomes Definitions and Statistical Tests in Oncology Studies: A Systematic Review of the Reporting Consistency

PubMed Central

Rivoirard, Romain; Duplay, Vianney; Oriol, Mathieu; Tinquaut, Fabien; Chauvin, Franck; Magne, Nicolas; Bourmaud, Aurelie

2016-01-01

Background Quality of reporting for Randomized Clinical Trials (RCTs) in oncology was analyzed in several systematic reviews, but, in this setting, there is paucity of data for the outcomes definitions and consistency of reporting for statistical tests in RCTs and Observational Studies (OBS). The objective of this review was to describe those two reporting aspects, for OBS and RCTs in oncology. Methods From a list of 19 medical journals, three were retained for analysis, after a random selection: British Medical Journal (BMJ), Annals of Oncology (AoO) and British Journal of Cancer (BJC). All original articles published between March 2009 and March 2014 were screened. Only studies whose main outcome was accompanied by a corresponding statistical test were included in the analysis. Studies based on censored data were excluded. Primary outcome was to assess quality of reporting for description of primary outcome measure in RCTs and of variables of interest in OBS. A logistic regression was performed to identify covariates of studies potentially associated with concordance of tests between Methods and Results parts. Results 826 studies were included in the review, and 698 were OBS. Variables were described in Methods section for all OBS studies and primary endpoint was clearly detailed in Methods section for 109 RCTs (85.2%). 295 OBS (42.2%) and 43 RCTs (33.6%) had perfect agreement for reported statistical test between Methods and Results parts. In multivariable analysis, variable "number of included patients in study" was associated with test consistency: aOR (adjusted Odds Ratio) for third group compared to first group was equal to: aOR Grp3 = 0.52 [0.31–0.89] (P value = 0.009). Conclusion Variables in OBS and primary endpoint in RCTs are reported and described with a high frequency. However, statistical tests consistency between methods and Results sections of OBS is not always noted. Therefore, we encourage authors and peer reviewers to verify consistency of statistical tests in oncology studies. PMID:27716793

A new method of sweat testing: the CF Quantum®sweat test.

PubMed

Rock, Michael J; Makholm, Linda; Eickhoff, Jens

2014-09-01

Conventional methods of sweat testing are time consuming and have many steps that can and do lead to errors. This study compares conventional sweat testing to a new quantitative method, the CF Quantum® (CFQT) sweat test. This study tests the diagnostic accuracy and analytic validity of the CFQT. Previously diagnosed CF patients and patients who required a sweat test for clinical indications were invited to have the CFQT test performed. Both conventional sweat testing and the CFQT were performed bilaterally on the same day. Pairs of data from each test are plotted as a correlation graph and Bland-Altman plot. Sensitivity and specificity were calculated as well as the means and coefficient of variation by test and by extremity. After completing the study, subjects or their parents were asked for their preference of the CFQT and conventional sweat testing. The correlation coefficient between the CFQT and conventional sweat testing was 0.98 (95% confidence interval: 0.97-0.99). The sensitivity and specificity of the CFQT in diagnosing CF was 100% (95% confidence interval: 94-100%) and 96% (95% confidence interval: 89-99%), respectively. In one center in this three center multicenter study, there were higher sweat chloride values in patients with CF and also more tests that were invalid due to discrepant values between the two extremities. The percentage of invalid tests was higher in the CFQT method (16.5%) compared to conventional sweat testing (3.8%) (p < 0.001). In the post-test questionnaire, 88% of subjects/parents preferred the CFQT test. The CFQT is a fast and simple method of quantitative sweat chloride determination. This technology requires further refinement to improve the analytic accuracy at higher sweat chloride values and to decrease the number of invalid tests. Copyright © 2014 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

Tests of Measurement Invariance without Subgroups: A Generalization of Classical Methods

ERIC Educational Resources Information Center

Merkle, Edgar C.; Zeileis, Achim

2013-01-01

The issue of measurement invariance commonly arises in factor-analytic contexts, with methods for assessment including likelihood ratio tests, Lagrange multiplier tests, and Wald tests. These tests all require advance definition of the number of groups, group membership, and offending model parameters. In this paper, we study tests of measurement…

Meta-analysis of diagnostic accuracy studies in mental health

PubMed Central

Takwoingi, Yemisi; Riley, Richard D; Deeks, Jonathan J

2015-01-01

Objectives To explain methods for data synthesis of evidence from diagnostic test accuracy (DTA) studies, and to illustrate different types of analyses that may be performed in a DTA systematic review. Methods We described properties of meta-analytic methods for quantitative synthesis of evidence. We used a DTA review comparing the accuracy of three screening questionnaires for bipolar disorder to illustrate application of the methods for each type of analysis. Results The discriminatory ability of a test is commonly expressed in terms of sensitivity (proportion of those with the condition who test positive) and specificity (proportion of those without the condition who test negative). There is a trade-off between sensitivity and specificity, as an increasing threshold for defining test positivity will decrease sensitivity and increase specificity. Methods recommended for meta-analysis of DTA studies --such as the bivariate or hierarchical summary receiver operating characteristic (HSROC) model --jointly summarise sensitivity and specificity while taking into account this threshold effect, as well as allowing for between study differences in test performance beyond what would be expected by chance. The bivariate model focuses on estimation of a summary sensitivity and specificity at a common threshold while the HSROC model focuses on the estimation of a summary curve from studies that have used different thresholds. Conclusions Meta-analyses of diagnostic accuracy studies can provide answers to important clinical questions. We hope this article will provide clinicians with sufficient understanding of the terminology and methods to aid interpretation of systematic reviews and facilitate better patient care. PMID:26446042

Evaluation of selected static methods used to estimate element mobility, acid-generating and acid-neutralizing potentials associated with geologically diverse mining wastes

USGS Publications Warehouse

Hageman, Philip L.; Seal, Robert R.; Diehl, Sharon F.; Piatak, Nadine M.; Lowers, Heather

2015-01-01

A comparison study of selected static leaching and acid–base accounting (ABA) methods using a mineralogically diverse set of 12 modern-style, metal mine waste samples was undertaken to understand the relative performance of the various tests. To complement this study, in-depth mineralogical studies were conducted in order to elucidate the relationships between sample mineralogy, weathering features, and leachate and ABA characteristics. In part one of the study, splits of the samples were leached using six commonly used leaching tests including paste pH, the U.S. Geological Survey (USGS) Field Leach Test (FLT) (both 5-min and 18-h agitation), the U.S. Environmental Protection Agency (USEPA) Method 1312 SPLP (both leachate pH 4.2 and leachate pH 5.0), and the USEPA Method 1311 TCLP (leachate pH 4.9). Leachate geochemical trends were compared in order to assess differences, if any, produced by the various leaching procedures. Results showed that the FLT (5-min agitation) was just as effective as the 18-h leaching tests in revealing the leachate geochemical characteristics of the samples. Leaching results also showed that the TCLP leaching test produces inconsistent results when compared to results produced from the other leaching tests. In part two of the study, the ABA was determined on splits of the samples using both well-established traditional static testing methods and a relatively quick, simplified net acid–base accounting (NABA) procedure. Results showed that the traditional methods, while time consuming, provide the most in-depth data on both the acid generating, and acid neutralizing tendencies of the samples. However, the simplified NABA method provided a relatively fast, effective estimation of the net acid–base account of the samples. Overall, this study showed that while most of the well-established methods are useful and effective, the use of a simplified leaching test and the NABA acid–base accounting method provide investigators fast, quantitative tools that can be used to provide rapid, reliable information about the leachability of metals and other constituents of concern, and the acid-generating potential of metal mining waste.

Agreement between gastrointestinal panel testing and standard microbiology methods for detecting pathogens in suspected infectious gastroenteritis: Test evaluation and meta-analysis in the absence of a reference standard.

PubMed

Freeman, Karoline; Tsertsvadze, Alexander; Taylor-Phillips, Sian; McCarthy, Noel; Mistry, Hema; Manuel, Rohini; Mason, James

2017-01-01

Multiplex gastrointestinal pathogen panel (GPP) tests simultaneously identify bacterial, viral and parasitic pathogens from the stool samples of patients with suspected infectious gastroenteritis presenting in hospital or the community. We undertook a systematic review to compare the accuracy of GPP tests with standard microbiology techniques. Searches in Medline, Embase, Web of Science and the Cochrane library were undertaken from inception to January 2016. Eligible studies compared GPP tests with standard microbiology techniques in patients with suspected gastroenteritis. Quality assessment of included studies used tailored QUADAS-2. In the absence of a reference standard we analysed test performance taking GPP tests and standard microbiology techniques in turn as the benchmark test, using random effects meta-analysis of proportions. No study provided an adequate reference standard with which to compare the test accuracy of GPP and conventional tests. Ten studies informed a meta-analysis of positive and negative agreement. Positive agreement across all pathogens was 0.93 (95% CI 0.90 to 0.96) when conventional methods were the benchmark and 0.68 (95% CI: 0.58 to 0.77) when GPP provided the benchmark. Negative agreement was high in both instances due to the high proportion of negative cases. GPP testing produced a greater number of pathogen-positive findings than conventional testing. It is unclear whether these additional 'positives' are clinically important. GPP testing has the potential to simplify testing and accelerate reporting when compared to conventional microbiology methods. However the impact of GPP testing upon the management, treatment and outcome of patients is poorly understood and further studies are needed to evaluate the health economic impact of GPP testing compared with standard methods. The review protocol is registered with PROSPERO as CRD42016033320.

Validation of Alternative In Vitro Methods to Animal Testing: Concepts, Challenges, Processes and Tools.

PubMed

Griesinger, Claudius; Desprez, Bertrand; Coecke, Sandra; Casey, Warren; Zuang, Valérie

This chapter explores the concepts, processes, tools and challenges relating to the validation of alternative methods for toxicity and safety testing. In general terms, validation is the process of assessing the appropriateness and usefulness of a tool for its intended purpose. Validation is routinely used in various contexts in science, technology, the manufacturing and services sectors. It serves to assess the fitness-for-purpose of devices, systems, software up to entire methodologies. In the area of toxicity testing, validation plays an indispensable role: "alternative approaches" are increasingly replacing animal models as predictive tools and it needs to be demonstrated that these novel methods are fit for purpose. Alternative approaches include in vitro test methods, non-testing approaches such as predictive computer models up to entire testing and assessment strategies composed of method suites, data sources and decision-aiding tools. Data generated with alternative approaches are ultimately used for decision-making on public health and the protection of the environment. It is therefore essential that the underlying methods and methodologies are thoroughly characterised, assessed and transparently documented through validation studies involving impartial actors. Importantly, validation serves as a filter to ensure that only test methods able to produce data that help to address legislative requirements (e.g. EU's REACH legislation) are accepted as official testing tools and, owing to the globalisation of markets, recognised on international level (e.g. through inclusion in OECD test guidelines). Since validation creates a credible and transparent evidence base on test methods, it provides a quality stamp, supporting companies developing and marketing alternative methods and creating considerable business opportunities. Validation of alternative methods is conducted through scientific studies assessing two key hypotheses, reliability and relevance of the test method for a given purpose. Relevance encapsulates the scientific basis of the test method, its capacity to predict adverse effects in the "target system" (i.e. human health or the environment) as well as its applicability for the intended purpose. In this chapter we focus on the validation of non-animal in vitro alternative testing methods and review the concepts, challenges, processes and tools fundamental to the validation of in vitro methods intended for hazard testing of chemicals. We explore major challenges and peculiarities of validation in this area. Based on the notion that validation per se is a scientific endeavour that needs to adhere to key scientific principles, namely objectivity and appropriate choice of methodology, we examine basic aspects of study design and management, and provide illustrations of statistical approaches to describe predictive performance of validated test methods as well as their reliability.

Measuring Core/Facesheet Bond Toughness in Honeycomb Sandwich Structures

NASA Technical Reports Server (NTRS)

Nettles, A. T.

2006-01-01

This study examines two test methods to evaluate the peel toughness of the skin to core debond of sandwich panels. The methods tested were the climbing drum (CD) peel test and the double cantilever beam (DCB) test. While the CD peel test is only intended for qualitative measurements, it is shown in this study that qualitative measurements can be performed and compare well with DCB test data. It is also shown that artificially stiffening the facesheets of a DCB specimen can cause the test to behave more like a flatwise tensile test than a peel test.

Evaluation of Modification of the 3M™ Molecular Detection Assay (MDA) Salmonella Method (2013.09) for the Detection of Salmonella in Selected Foods: Collaborative Study.

PubMed

Bird, Patrick; Fisher, Kiel; Boyle, Megan; Huffman, Travis; Benzinger, M Joseph; Bedinghaus, Paige; Flannery, Jonathon; Crowley, Erin; Agin, James; Goins, David; Benesh, DeAnn; David, John

2014-01-01

The 3M(™) Molecular Detection Assay (MDA) Salmonella utilizes isothermal amplification of nucleic acid sequences with high specificity, efficiency, rapidity and bioluminescence to detect amplification of Salmonella spp. in food, food-related, and environmental samples after enrichment. A method modification and matrix extension study of the previously approved AOAC Official Method(SM) 2013.09 was conducted, and approval of the modification was received on March 20, 2014. Using an unpaired study design in a multilaboratory collaborative study, the 3M MDA Salmonella method was compared to the U.S. Department of Agriculture/Food Safety and Inspection Service (USDA/FSIS) Microbiology Laboratory Guidebook (MLG) 4.05 (2011), Isolation and Identification of Salmonella from Meat, Poultry, Pasteurized Egg, and Catfish Products for raw ground beef and the U.S. Food and Drug Administration (FDA)/Bacteriological Analytical Manual (BAM) Chapter 5, Salmonella reference method for wet dog food following the current AOAC guidelines. A total of 20 laboratories participated. For the 3M MDA Salmonella method, raw ground beef was analyzed using 25 g test portions, and wet dog food was analyzed using 375 g test portions. For the reference methods, 25 g test portions of each matrix were analyzed. Each matrix was artificially contaminated with Salmonella at three inoculation levels: an uninoculated control level (0 CFU/test portion), a low inoculum level (0.2-2 CFU/test portion), and a high inoculum level (2-5 CFU/test portion). In this study, 1512 unpaired replicate samples were analyzed. Statistical analysis was conducted according to the probability of detection (POD). For the low-level raw ground beef test portions, the following dLPOD (difference between the LPODs of the reference and candidate method) values with 95% confidence intervals were obtained: -0.01 (-0.14, +0.12). For the low-level wet dog food test portions, the following dLPOD with 95% confidence intervals were obtained: -0.04 (-0.16, +0.09). No significant differences were observed in the number of positive samples detected by the 3M MDA Salmonella method versus either the USDA/FSIS-MLG or FDA/BAM methods.

The Effect of Schooling and Ability on Achievement Test Scores. NBER Working Paper Series.

ERIC Educational Resources Information Center

Hansen, Karsten; Heckman, James J.; Mullen, Kathleen J.

This study developed two methods for estimating the effect of schooling on achievement test scores that control for the endogeneity of schooling by postulating that both schooling and test scores are generated by a common unobserved latent ability. The methods were applied to data on schooling and test scores. Estimates from the two methods are in…

Method of Curved Models and Its Application to the Study of Curvilinear Flight of Airships. Part II

NASA Technical Reports Server (NTRS)

Gourjienko, G A

1937-01-01

This report compares the results obtained by the aid of curved models with the results of tests made by the method of damped oscillations, and with flight tests. Consequently we shall be able to judge which method of testing in the tunnel produces results that are in closer agreement with flight test results.

Vacuum decay container/closure integrity testing technology. Part 2. Comparison to dye ingress tests.

PubMed

Wolf, Heinz; Stauffer, Tony; Chen, Shu-Chen Y; Lee, Yoojin; Forster, Ronald; Ludzinski, Miron; Kamat, Madhav; Mulhall, Brian; Guazzo, Dana Morton

2009-01-01

Part 1 of this series demonstrated that a container closure integrity test performed according to ASTM F2338-09 Standard Test Method for Nondestructive Detection of Leaks in Packages by Vacuum Decay Method using a VeriPac 325/LV vacuum decay leak tester by Packaging Technologies & Inspection, LLC (PTI) is capable of detecting leaks > or = 5.0 microm (nominal diameter) in rigid, nonporous package systems, such as prefilled glass syringes. The current study compared USP, Ph.Eur. and ISO dye ingress integrity test methods to PTI's vacuum decay technology for the detection of these same 5-, 10-, and 15-microm laser-drilled hole defects in 1-mL glass prefilled syringes. The study was performed at three test sites using several inspectors and a variety of inspection conditions. No standard dye ingress method was found to reliably identify all holed syringes. Modifications to these standard dye tests' challenge conditions increased the potential for dye ingress, and adjustments to the visual inspection environment improved dye ingress detection. However, the risk of false positive test results with dye ingress tests remained. In contrast, the nondestructive vacuum decay leak test method reliably identified syringes with holes > or = 5.0 microm.

Statistics of software vulnerability detection in certification testing

NASA Astrophysics Data System (ADS)

Barabanov, A. V.; Markov, A. S.; Tsirlov, V. L.

2018-05-01

The paper discusses practical aspects of introduction of the methods to detect software vulnerability in the day-to-day activities of the accredited testing laboratory. It presents the approval results of the vulnerability detection methods as part of the study of the open source software and the software that is a test object of the certification tests under information security requirements, including software for communication networks. Results of the study showing the allocation of identified vulnerabilities by types of attacks, country of origin, programming languages used in the development, methods for detecting vulnerability, etc. are given. The experience of foreign information security certification systems related to the detection of certified software vulnerabilities is analyzed. The main conclusion based on the study is the need to implement practices for developing secure software in the development life cycle processes. The conclusions and recommendations for the testing laboratories on the implementation of the vulnerability analysis methods are laid down.

A Multi-Method Approach to Studying the Relationship between Character Strengths and Vocational Interests in Adolescents

ERIC Educational Resources Information Center

Proyer, Rene T.; Sidler, Nicole; Weber, Marco; Ruch, Willibald

2012-01-01

The relationship between character strengths and vocational interests was tested. In an online study, 197 thirteen to eighteen year-olds completed a questionnaire measuring character strengths and a multi-method measure for interests (questionnaire, nonverbal test, and objective personality tests). The main findings were that intellectual…

Development of a REBCO HTS magnet for Maglev - repeated bending tests of HTS pancake coils -

NASA Astrophysics Data System (ADS)

Sugino, Motohikoa; Mizuno, Katsutoshi; Tanaka, Minoru; Ogata, Masafumi

2018-01-01

In the past study, two manufacturing methods were developed that can manufacture pancake coils by using REBCO coated conductors. It was confirmed that the conductors have no electric degradation that caused by the manufacturing method. The durability evaluation tests of the pancake coils were conducted as the final evaluation of the coil manufacturing method in this study. The repeated bending deformation was applied to manufactured pancake coils in the tests. As the results of these tests, it was confirmed that the pancake coils that were manufactured by two methods had the durability for the repeated bending deformation and the coils maintained the appropriate mechanical performance and electric performance. We adopted the fusion bonding method as the coil manufacturing method of the HTS magnet Furthermore, using the prototype pancake coil that was manufactured by the fusion bonding method as a test sample, the repeated bending test under the exited condition was conducted. Thus it was confirmed that the coil manufactured by the fusion bonding method has no degradation of the electricity performance and the mechanical properties even if the repeated bending deformation was applied under the exited condition.

EVALUATION AND IMPORTANCE OF SELECTED MICROBIOLOGICAL METHODS IN THE DIAGNOSIS OF HUMAN BRUCELLOSIS

PubMed Central

Šiširak, Maida; Hukić, Mirsada

2009-01-01

Brucellosis is an important public health problem in Bosnia and Herzegovina. The diagnosis of bru-cellosis in the country without any experiences with this kind of infection may be very difficult. The aim of this study was to evaluate diagnostic methods: Rose Bengal test, blood cultures and ELISA IgM and IgG in the patients with brucellosis. The study included 91 brucellosis patients in the period 2004 to 2007. All the patients were treated at the Clinic for Infectious Diseases, University of Sarajevo Clinics Centre. Blood cultures were positive in 28/91 (30, 8%) patients. This method often needs a long period of incubation and specimens need to be obtained early. These limitations make serology the most useful tool for the laboratory diagnosis of Brucella infection. Rose Bengal is a rapid plate agglutination test, very sensitive irrespective of the stage of the disease. In our study, Rose Bengal test was positive in all patients 91/91 (100, 0%). Brucella IgM antibodies with ELISA were positive in 59/91 (64, 8%). Brucella IgG antibodies with ELISA were positive in 51/91 (56%). In order to determine the diagnostic value of the different tests, we compared the sensitivity among test-methods: Rose Bengal test-100.0%, blood culture-30.8%, ELISA IgM-64.8% and ELISA IgG-56.1%. Sensitivity of test methods was different in the different stages of illness. It is necessary to use combination of different tests such are blood culture, Rose Bengal test and ELISA in order to ensure the diagnosis. Rose Bengal test is excellent for the screening. Blood culture is a method of choice for the diagnosis acute infection. ELISA is a very good method for the diagnostic chronic disease and relapse. PMID:19754473

The PneuCarriage Project: A Multi-Centre Comparative Study to Identify the Best Serotyping Methods for Examining Pneumococcal Carriage in Vaccine Evaluation Studies

PubMed Central

Satzke, Catherine; Dunne, Eileen M.; Porter, Barbara D.; Klugman, Keith P.; Mulholland, E. Kim

2015-01-01

Background The pneumococcus is a diverse pathogen whose primary niche is the nasopharynx. Over 90 different serotypes exist, and nasopharyngeal carriage of multiple serotypes is common. Understanding pneumococcal carriage is essential for evaluating the impact of pneumococcal vaccines. Traditional serotyping methods are cumbersome and insufficient for detecting multiple serotype carriage, and there are few data comparing the new methods that have been developed over the past decade. We established the PneuCarriage project, a large, international multi-centre study dedicated to the identification of the best pneumococcal serotyping methods for carriage studies. Methods and Findings Reference sample sets were distributed to 15 research groups for blinded testing. Twenty pneumococcal serotyping methods were used to test 81 laboratory-prepared (spiked) samples. The five top-performing methods were used to test 260 nasopharyngeal (field) samples collected from children in six high-burden countries. Sensitivity and positive predictive value (PPV) were determined for the test methods and the reference method (traditional serotyping of >100 colonies from each sample). For the alternate serotyping methods, the overall sensitivity ranged from 1% to 99% (reference method 98%), and PPV from 8% to 100% (reference method 100%), when testing the spiked samples. Fifteen methods had ≥70% sensitivity to detect the dominant (major) serotype, whilst only eight methods had ≥70% sensitivity to detect minor serotypes. For the field samples, the overall sensitivity ranged from 74.2% to 95.8% (reference method 93.8%), and PPV from 82.2% to 96.4% (reference method 99.6%). The microarray had the highest sensitivity (95.8%) and high PPV (93.7%). The major limitation of this study is that not all of the available alternative serotyping methods were included. Conclusions Most methods were able to detect the dominant serotype in a sample, but many performed poorly in detecting the minor serotype populations. Microarray with a culture amplification step was the top-performing method. Results from this comprehensive evaluation will inform future vaccine evaluation and impact studies, particularly in low-income settings, where pneumococcal disease burden remains high. PMID:26575033

Solar panel thermal cycling testing by solar simulation and infrared radiation methods

NASA Technical Reports Server (NTRS)

Nuss, H. E.

1980-01-01

For the solar panels of the European Space Agency (ESA) satellites OTS/MAROTS and ECS/MARECS the thermal cycling tests were performed by using solar simulation methods. The performance data of two different solar simulators used and the thermal test results are described. The solar simulation thermal cycling tests for the ECS/MARECS solar panels were carried out with the aid of a rotatable multipanel test rig by which simultaneous testing of three solar panels was possible. As an alternative thermal test method, the capability of an infrared radiation method was studied and infrared simulation tests for the ultralight panel and the INTELSAT 5 solar panels were performed. The setup and the characteristics of the infrared radiation unit using a quartz lamp array of approx. 15 sq and LN2-cooled shutter and the thermal test results are presented. The irradiation uniformity, the solar panel temperature distribution, temperature changing rates for both test methods are compared. Results indicate the infrared simulation is an effective solar panel thermal testing method.

Performance of the AOAC use-dilution method with targeted modifications: collaborative study.

PubMed

Tomasino, Stephen F; Parker, Albert E; Hamilton, Martin A; Hamilton, Gordon C

2012-01-01

The U.S. Environmental Protection Agency (EPA), in collaboration with an industry work group, spearheaded a collaborative study designed to further enhance the AOAC use-dilution method (UDM). Based on feedback from laboratories that routinely conduct the UDM, improvements to the test culture preparation steps were prioritized. A set of modifications, largely based on culturing the test microbes on agar as specified in the AOAC hard surface carrier test method, were evaluated in a five-laboratory trial. The modifications targeted the preparation of the Pseudomonas aeruginosa test culture due to the difficulty in separating the pellicle from the broth in the current UDM. The proposed modifications (i.e., the modified UDM) were compared to the current UDM methodology for P. aeruginosa and Staphylococcus aureus. Salmonella choleraesuis was not included in the study. The goal was to determine if the modifications reduced method variability. Three efficacy response variables were statistically analyzed: the number of positive carriers, the log reduction, and the pass/fail outcome. The scope of the collaborative study was limited to testing one liquid disinfectant (an EPA-registered quaternary ammonium product) at two levels of presumed product efficacies, high and low. Test conditions included use of 400 ppm hard water as the product diluent and a 5% organic soil load (horse serum) added to the inoculum. Unfortunately, the study failed to support the adoption of the major modification (use of an agar-based approach to grow the test cultures) based on an analysis of method's variability. The repeatability and reproducibility standard deviations for the modified method were equal to or greater than those for the current method across the various test variables. However, the authors propose retaining the frozen stock preparation step of the modified method, and based on the statistical equivalency of the control log densities, support its adoption as a procedural change to the current UDM. The current UDM displayed acceptable responsiveness to changes in product efficacy; acceptable repeatability across multiple tests in each laboratory for the control counts and log reductions; and acceptable reproducibility across multiple laboratories for the control log density values and log reductions. Although the data do not support the adoption of all modifications, the UDM collaborative study data are valuable for assessing sources of method variability and a reassessment of the performance standard for the UDM.

Structural Integrity Testing Method for PRSEUS Rod-Wrap Stringer Design

NASA Technical Reports Server (NTRS)

Wang, John T.; Grenoble, Ray W.; Pickell, Robert D.

2012-01-01

NASA Langley Research Center and The Boeing Company are developing an innovative composite structural concept, called PRSEUS, for the flat center section of a future environmentally friendly hybrid wing body (HWB) aircraft. The PRSEUS (Pultruded Rod Stitched Efficient Unitized Structure) concept uses dry textile preforms for the skins, frames, and stiffener webs. The highly loaded stiffeners are made from precured unidirectional carbon/epoxy rods and dry fiber preforms. The rods are wrapped with the dry fiber preforms and a resin infusion process is used to form the rod-wrap stiffeners. The structural integrity of the rod-wrap interface is critical for maintaining the panel s high strength and bending rigidity. No standard testing method exists for testing the strength of the rod-wrap bondline. Recently, Boeing proposed a rod push-out testing method and conducted some preliminary tests using this method. This paper details an analytical study of the rod-wrap bondline. The rod-wrap interface is modeled as a cohesive zone for studying the initiation and growth of interfacial debonding during push-out testing. Based on the correlations of analysis results and Boeing s test data, the adequacy of the rod-wrap testing method is evaluated, and potential approaches for improvement of the test method are proposed.

A comparison of 2 methods of endoscopic laryngeal sensory testing: a preliminary study.

PubMed

Kaneoka, Asako; Krisciunas, Gintas P; Walsh, Kayo; Raade, Adele S; Langmore, Susan E

2015-03-01

This study examined the association between laryngeal sensory deficits and penetration or aspiration. Two methods of testing laryngeal sensation were carried out to determine which was more highly correlated with Penetration-Aspiration Scale (PAS) scores. Healthy participants and patients with dysphagia received an endoscopic swallowing evaluation including 2 sequential laryngeal sensory tests-air pulse followed by touch method. Normal/impaired responses were correlated with PAS scores. Fourteen participants completed the endoscopic swallowing evaluation and both sensory tests. The air pulse method identified sensory impairment with greater frequency than the touch method (P<.0001). However, the impairment identified by the air pulse method was not associated with abnormal PAS scores (P=.46). The sensory deficits identified by the touch method were associated with abnormal PAS scores (P=.05). Sensory impairment detected by the air pulse method does not appear to be associated with risk of penetration/aspiration. Significant laryngeal sensory loss revealed by the touch method is associated with compromised airway protection. © The Author(s) 2014.

Using Epidemiologic Methods to Test Hypotheses regarding Causal Influences on Child and Adolescent Mental Disorders

ERIC Educational Resources Information Center

Lahey, Benjamin B.; D'Onofrio, Brian M.; Waldman, Irwin D.

2009-01-01

Epidemiology uses strong sampling methods and study designs to test refutable hypotheses regarding the causes of important health, mental health, and social outcomes. Epidemiologic methods are increasingly being used to move developmental psychopathology from studies that catalogue correlates of child and adolescent mental health to designs that…

The PneuCarriage Project: A Multi-Centre Comparative Study to Identify the Best Serotyping Methods for Examining Pneumococcal Carriage in Vaccine Evaluation Studies.

PubMed

Satzke, Catherine; Dunne, Eileen M; Porter, Barbara D; Klugman, Keith P; Mulholland, E Kim

2015-11-01

The pneumococcus is a diverse pathogen whose primary niche is the nasopharynx. Over 90 different serotypes exist, and nasopharyngeal carriage of multiple serotypes is common. Understanding pneumococcal carriage is essential for evaluating the impact of pneumococcal vaccines. Traditional serotyping methods are cumbersome and insufficient for detecting multiple serotype carriage, and there are few data comparing the new methods that have been developed over the past decade. We established the PneuCarriage project, a large, international multi-centre study dedicated to the identification of the best pneumococcal serotyping methods for carriage studies. Reference sample sets were distributed to 15 research groups for blinded testing. Twenty pneumococcal serotyping methods were used to test 81 laboratory-prepared (spiked) samples. The five top-performing methods were used to test 260 nasopharyngeal (field) samples collected from children in six high-burden countries. Sensitivity and positive predictive value (PPV) were determined for the test methods and the reference method (traditional serotyping of >100 colonies from each sample). For the alternate serotyping methods, the overall sensitivity ranged from 1% to 99% (reference method 98%), and PPV from 8% to 100% (reference method 100%), when testing the spiked samples. Fifteen methods had ≥70% sensitivity to detect the dominant (major) serotype, whilst only eight methods had ≥70% sensitivity to detect minor serotypes. For the field samples, the overall sensitivity ranged from 74.2% to 95.8% (reference method 93.8%), and PPV from 82.2% to 96.4% (reference method 99.6%). The microarray had the highest sensitivity (95.8%) and high PPV (93.7%). The major limitation of this study is that not all of the available alternative serotyping methods were included. Most methods were able to detect the dominant serotype in a sample, but many performed poorly in detecting the minor serotype populations. Microarray with a culture amplification step was the top-performing method. Results from this comprehensive evaluation will inform future vaccine evaluation and impact studies, particularly in low-income settings, where pneumococcal disease burden remains high.

Receiver operating characteristic (ROC) curves: review of methods with applications in diagnostic medicine

NASA Astrophysics Data System (ADS)

Obuchowski, Nancy A.; Bullen, Jennifer A.

2018-04-01

Receiver operating characteristic (ROC) analysis is a tool used to describe the discrimination accuracy of a diagnostic test or prediction model. While sensitivity and specificity are the basic metrics of accuracy, they have many limitations when characterizing test accuracy, particularly when comparing the accuracies of competing tests. In this article we review the basic study design features of ROC studies, illustrate sample size calculations, present statistical methods for measuring and comparing accuracy, and highlight commonly used ROC software. We include descriptions of multi-reader ROC study design and analysis, address frequently seen problems of verification and location bias, discuss clustered data, and provide strategies for testing endpoints in ROC studies. The methods are illustrated with a study of transmission ultrasound for diagnosing breast lesions.

Effects of test method and participant musical training on preference ratings of stimuli with different reverberation times.

PubMed

Lawless, Martin S; Vigeant, Michelle C

2017-10-01

Selecting an appropriate listening test design for concert hall research depends on several factors, including listening test method and participant critical-listening experience. Although expert listeners afford more reliable data, their perceptions may not be broadly representative. The present paper contains two studies that examined the validity and reliability of the data obtained from two listening test methods, a successive and a comparative method, and two types of participants, musicians and non-musicians. Participants rated their overall preference of auralizations generated from eight concert hall conditions with a range of reverberation times (0.0-7.2 s). Study 1, with 34 participants, assessed the two methods. The comparative method yielded similar results and reliability as the successive method. Additionally, the comparative method was rated as less difficult and more preferable. For study 2, an additional 37 participants rated the stimuli using the comparative method only. An analysis of variance of the responses from both studies revealed that musicians are better than non-musicians at discerning their preferences across stimuli. This result was confirmed with a k-means clustering analysis on the entire dataset that revealed five preference groups. Four groups exhibited clear preferences to the stimuli, while the fifth group, predominantly comprising non-musicians, demonstrated no clear preference.

Experimental and simulation flow rate analysis of the 3/2 directional pneumatic valve

NASA Astrophysics Data System (ADS)

Blasiak, Slawomir; Takosoglu, Jakub E.; Laski, Pawel A.; Pietrala, Dawid S.; Zwierzchowski, Jaroslaw; Bracha, Gabriel; Nowakowski, Lukasz; Blasiak, Malgorzata

The work includes a study on the comparative analysis of two test methods. The first method - numerical method, consists in determining the flow characteristics with the use of ANSYS CFX. A modeled poppet directional valve 3/2 3D CAD software - SolidWorks was used for this purpose. Based on the solid model that was developed, simulation studies of the air flow through the way valve in the software for computational fluid dynamics Ansys CFX were conducted. The second method - experimental, entailed conducting tests on a specially constructed test stand. The comparison of the test results obtained on the basis of both methods made it possible to determine the cross-correlation. High compatibility of the results confirms the usefulness of the numerical procedures. Thus, they might serve to determine the flow characteristics of directional valves as an alternative to a costly and time-consuming test stand.

Study on ABO and RhD blood grouping: Comparison between conventional tile method and a new solid phase method (InTec Blood Grouping Test Kit).

PubMed

Yousuf, R; Abdul Ghani, S A; Abdul Khalid, N; Leong, C F

2018-04-01

'InTec Blood Grouping Test kit' using solid-phase technology is a new method which may be used at outdoor blood donation site or at bed side as an alternative to the conventional tile method in view of its stability at room temperature and fulfilled the criteria as point of care test. This study aimed to compare the efficiency of this solid phase method (InTec Blood Grouping Test Kit) with the conventional tile method in determining the ABO and RhD blood group of healthy donors. A total of 760 voluntary donors who attended the Blood Bank, Penang Hospital or offsite blood donation campaigns from April to May 2014 were recruited. The ABO and RhD blood groups were determined by the conventional tile method and the solid phase method, in which the tube method was used as the gold standard. For ABO blood grouping, the tile method has shown 100% concordance results with the gold standard tube method, whereas the solid-phase method only showed concordance result for 754/760 samples (99.2%). Therefore, for ABO grouping, tile method has 100% sensitivity and specificity while the solid phase method has slightly lower sensitivity of 97.7% but both with good specificity of 100%. For RhD grouping, both the tile and solid phase methods have grouped one RhD positive specimen as negative each, thus giving the sensitivity and specificity of 99.9% and 100% for both methods respectively. The 'InTec Blood Grouping Test Kit' is suitable for offsite usage because of its simplicity and user friendliness. However, further improvement in adding the internal quality control may increase the test sensitivity and validity of the test results.

Methods specification for diagnostic test accuracy studies in fine-needle aspiration cytology: a survey of reporting practice.

PubMed

Schmidt, Robert L; Factor, Rachel E; Affolter, Kajsa E; Cook, Joshua B; Hall, Brian J; Narra, Krishna K; Witt, Benjamin L; Wilson, Andrew R; Layfield, Lester J

2012-01-01

Diagnostic test accuracy (DTA) studies on fine-needle aspiration cytology (FNAC) often show considerable variability in diagnostic accuracy between study centers. Many factors affect the accuracy of FNAC. A complete description of the testing parameters would help make valid comparisons between studies and determine causes of performance variation. We investigated the manner in which test conditions are specified in FNAC DTA studies to determine which parameters are most commonly specified and the frequency with which they are specified and to see whether there is significant variability in reporting practice. We identified 17 frequently reported test parameters and found significant variation in the reporting of these test specifications across studies. On average, studies reported 5 of the 17 items that would be required to specify the test conditions completely. A more complete and standardized reporting of methods, perhaps by means of a checklist, would improve the interpretation of FNAC DTA studies.

Post-hoc simulation study to adopt a computerized adaptive testing (CAT) for a Korean Medical License Examination.

PubMed

Seo, Dong Gi; Choi, Jeongwook

2018-05-17

Computerized adaptive testing (CAT) has been adopted in license examinations due to a test efficiency and accuracy. Many research about CAT have been published to prove the efficiency and accuracy of measurement. This simulation study investigated scoring method and item selection methods to implement CAT in Korean medical license examination (KMLE). This study used post-hoc (real data) simulation design. The item bank used in this study was designed with all items in a 2017 KMLE. All CAT algorithms for this study were implemented by a 'catR' package in R program. In terms of accuracy, Rasch and 2parametric logistic (PL) model performed better than 3PL model. Modal a Posteriori (MAP) or Expected a Posterior (EAP) provided more accurate estimates than MLE and WLE. Furthermore Maximum posterior weighted information (MPWI) or Minimum expected posterior variance (MEPV) performed better than other item selection methods. In terms of efficiency, Rasch model was recommended to reduce test length. Simulation study should be performed under varied test conditions before adopting a live CAT. Based on a simulation study, specific scoring and item selection methods should be predetermined before implementing a live CAT.

A Comparison of Methods for Transforming Sentences into Test Questions for Instructional Materials. Technical Report #1.

ERIC Educational Resources Information Center

Roid, Gale; And Others

Several measurement theorists have convincingly argued that methods of writing test questions, particularly for criterion-referenced tests, should be based on operationally defined rules. This study was designed to examine and further refine a method for objectively generating multiple-choice questions for prose instructional materials. Important…

An Evaluation of the Kernel Equating Method: A Special Study with Pseudotests Constructed from Real Test Data. Research Report. ETS RR-06-02

ERIC Educational Resources Information Center

von Davier, Alina A.; Holland, Paul W.; Livingston, Samuel A.; Casabianca, Jodi; Grant, Mary C.; Martin, Kathleen

2006-01-01

This study examines how closely the kernel equating (KE) method (von Davier, Holland, & Thayer, 2004a) approximates the results of other observed-score equating methods--equipercentile and linear equatings. The study used pseudotests constructed of item responses from a real test to simulate three equating designs: an equivalent groups (EG)…

An Evaluation of Kernel Equating: Parallel Equating with Classical Methods in the SAT Subject Tests[TM] Program. Research Report. ETS RR-09-06

ERIC Educational Resources Information Center

Grant, Mary C.; Zhang, Lilly; Damiano, Michele

2009-01-01

This study investigated kernel equating methods by comparing these methods to operational equatings for two tests in the SAT Subject Tests[TM] program. GENASYS (ETS, 2007) was used for all equating methods and scaled score kernel equating results were compared to Tucker, Levine observed score, chained linear, and chained equipercentile equating…

Identifying High Academic Potential in Australian Aboriginal Children Using Dynamic Testing

ERIC Educational Resources Information Center

Chaffey, Graham W.; Bailey, Stan B.; Vine, Ken W.

2015-01-01

The primary purpose of this study was to determine the effectiveness of dynamic testing as a method for identifying high academic potential in Australian Aboriginal children. The 79 participating Aboriginal children were drawn from Years 3-5 in rural schools in northern New South Wales. The dynamic testing method used in this study involved a…

Manual of Scaling Methods

NASA Technical Reports Server (NTRS)

Bond, Thomas H. (Technical Monitor); Anderson, David N.

2004-01-01

This manual reviews the derivation of the similitude relationships believed to be important to ice accretion and examines ice-accretion data to evaluate their importance. Both size scaling and test-condition scaling methods employing the resulting similarity parameters are described, and experimental icing tests performed to evaluate scaling methods are reviewed with results. The material included applies primarily to unprotected, unswept geometries, but some discussion of how to approach other situations is included as well. The studies given here and scaling methods considered are applicable only to Appendix-C icing conditions. Nearly all of the experimental results presented have been obtained in sea-level tunnels. Recommendations are given regarding which scaling methods to use for both size scaling and test-condition scaling, and icing test results are described to support those recommendations. Facility limitations and size-scaling restrictions are discussed. Finally, appendices summarize the air, water and ice properties used in NASA scaling studies, give expressions for each of the similarity parameters used and provide sample calculations for the size-scaling and test-condition scaling methods advocated.

A new low-cost procedure for detecting nucleic acids in low-incidence samples: a case study of detecting spores of Paenibacillus larvae from bee debris.

PubMed

Ryba, Stepan; Kindlmann, Pavel; Titera, Dalibor; Haklova, Marcela; Stopka, Pavel

2012-10-01

American foulbrood, because of its virulence and worldwide spread, is currently one of the most dangerous diseases of honey bees. Quick diagnosis of this disease is therefore vitally important. For its successful eradication, however, all the hives in the region must be tested. This is time consuming and costly. Therefore, a fast and sensitive method of detecting American foulbrood is needed. Here we present a method that significantly reduces the number of tests needed by combining batches of samples from different hives. The results of this method were verified by testing each sample. A simulation study was used to compare the efficiency of the new method with testing all the samples and to develop a decision tool for determining when best to use the new method. The method is suitable for testing large numbers of samples (over 100) when the incidence of the disease is low (10% or less).

Laboratory based instruction in Pakistan: Comparative evaluation of three laboratory instruction methods in biological science at higher secondary school level

NASA Astrophysics Data System (ADS)

Cheema, Tabinda Shahid

This study of laboratory based instruction at higher secondary school level was an attempt to gain some insight into the effectiveness of three laboratory instruction methods: cooperative group instruction method, individualised instruction method and lecture demonstration method on biology achievement and retention. A Randomised subjects, Pre-test Post-test Comparative Methods Design was applied. Three groups of students from a year 11 class in Pakistan conducted experiments using the different laboratory instruction methods. Pre-tests, achievement tests after the experiments and retention tests one month later were administered. Results showed no significant difference between the groups on total achievement and retention, nor was there any significant difference on knowledge and comprehension test scores or skills performance. Future research investigating a similar problem is suggested.

Validation of alternative methods for toxicity testing.

PubMed Central

Bruner, L H; Carr, G J; Curren, R D; Chamberlain, M

1998-01-01

Before nonanimal toxicity tests may be officially accepted by regulatory agencies, it is generally agreed that the validity of the new methods must be demonstrated in an independent, scientifically sound validation program. Validation has been defined as the demonstration of the reliability and relevance of a test method for a particular purpose. This paper provides a brief review of the development of the theoretical aspects of the validation process and updates current thinking about objectively testing the performance of an alternative method in a validation study. Validation of alternative methods for eye irritation testing is a specific example illustrating important concepts. Although discussion focuses on the validation of alternative methods intended to replace current in vivo toxicity tests, the procedures can be used to assess the performance of alternative methods intended for other uses. Images Figure 1 PMID:9599695

Test Guideline Methods for Bed Bug Pesticide Products Now Available

EPA Pesticide Factsheets

EPA’s final test guidelines, 810.3900 - Laboratory Product Performance Testing Methods for Bed Bug Pesticide Products, provides recommendations for the design and execution of laboratory studies to evaluate the performance of pesticide products.

Validation in Support of Internationally Harmonised OECD Test Guidelines for Assessing the Safety of Chemicals.

PubMed

Gourmelon, Anne; Delrue, Nathalie

Ten years elapsed since the OECD published the Guidance document on the validation and international regulatory acceptance of test methods for hazard assessment. Much experience has been gained since then in validation centres, in countries and at the OECD on a variety of test methods that were subjected to validation studies. This chapter reviews validation principles and highlights common features that appear to be important for further regulatory acceptance across studies. Existing OECD-agreed validation principles will most likely generally remain relevant and applicable to address challenges associated with the validation of future test methods. Some adaptations may be needed to take into account the level of technique introduced in test systems, but demonstration of relevance and reliability will continue to play a central role as pre-requisite for the regulatory acceptance. Demonstration of relevance will become more challenging for test methods that form part of a set of predictive tools and methods, and that do not stand alone. OECD is keen on ensuring that while these concepts evolve, countries can continue to rely on valid methods and harmonised approaches for an efficient testing and assessment of chemicals.

Evaluation of dysphagia in early stroke patients by bedside, endoscopic, and electrophysiological methods.

PubMed

Umay, Ebru Karaca; Unlu, Ece; Saylam, Guleser Kılıc; Cakci, Aytul; Korkmaz, Hakan

2013-09-01

We aimed in this study to evaluate dysphagia in early stroke patients using a bedside screening test and flexible fiberoptic endoscopic evaluation of swallowing (FFEES) and electrophysiological evaluation (EE) methods and to compare the effectiveness of these methods. Twenty-four patients who were hospitalized in our clinic within the first 3 months after stroke were included in this study. Patients were evaluated using a bedside screening test [including bedside dysphagia score (BDS), neurological examination dysphagia score (NEDS), and total dysphagia score (TDS)] and FFEES and EE methods. Patients were divided into normal-swallowing and dysphagia groups according to the results of the evaluation methods. Patients with dysphagia as determined by any of these methods were compared to the patients with normal swallowing based on the results of the other two methods. Based on the results of our study, a high BDS was positively correlated with dysphagia identified by FFEES and EE methods. Moreover, the FFEES and EE methods were positively correlated. There was no significant correlation between NEDS and TDS levels and either EE or FFEES method. Bedside screening tests should be used mainly as an initial screening test; then FFEES and EE methods should be combined in patients who show risks. This diagnostic algorithm may provide a practical and fast solution for selected stroke patients.

Comparison of Three Methods of Reducing Test Anxiety: Systematic Desensitization, Implosive Therapy, and Study Counseling

ERIC Educational Resources Information Center

Cornish, Richard D.; Dilley, Josiah S.

1973-01-01

Systematic desensitization, implosive therapy, and study counseling have all been effective in reducing test anxiety. In addition, systematic desensitization has been compared to study counseling for effectiveness. This study compares all three methods and suggests that systematic desentization is more effective than the others, and that implosive…

Test methods for determining the suitability of metal alloys for use in oxygen-enriched environments

NASA Technical Reports Server (NTRS)

Stoltzfus, Joel M.; Gunaji, Mohan V.

1991-01-01

Materials are more flammable in oxygen rich environments than in air. When the structural elements of a system containing oxygen ignite and burn, the results are often catastrophic, causing loss of equipment and perhaps even human lives. Therefore, selection of the proper metallic and non-metallic materials for use in oxygen systems is extremely important. While test methods for the selection of non-metallic materials have been available for years, test methods for the selection of alloys have not been available until recently. Presented here are several test methods that were developed recently at NASA's White Sands Test Facility (WSTF) to study the ignition and combustion of alloys, including the supersonic and subsonic speed particle impact tests, the frictional heating and coefficient of friction tests, and the promoted combustion test. These test methods are available for commercial use.

Tests of Independence for Ordinal Data Using Bootstrap.

ERIC Educational Resources Information Center

Chan, Wai; Yung, Yiu-Fai; Bentler, Peter M.; Tang, Man-Lai

1998-01-01

Two bootstrap tests are proposed to test the independence hypothesis in a two-way cross table. Monte Carlo studies are used to compare the traditional asymptotic test with these bootstrap methods, and the bootstrap methods are found superior in two ways: control of Type I error and statistical power. (SLD)

Estimating Total-Test Scores from Partial Scores in a Matrix Sampling Design.

ERIC Educational Resources Information Center

Sachar, Jane; Suppes, Patrick

1980-01-01

The present study compared six methods, two of which utilize the content structure of items, to estimate total-test scores using 450 students and 60 items of the 110-item Stanford Mental Arithmetic Test. Three methods yielded fairly good estimates of the total-test score. (Author/RL)

Duct Leakage Repeatability Testing

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

Walker, Iain; Sherman, Max

2014-08-01

The purpose of this report is to evaluate the repeatability of the three most significant measurement techniques for duct leakage using data from the literature and recently obtained field data. We will also briefly discuss the first two factors. The main question to be answered by this study is to determine if differences in the repeatability of these tests methods is sufficient to indicate that any of these methods is so poor that it should be excluded from consideration as an allowed procedure in codes and standards. The three duct leak measurement methods assessed in this report are the twomore » duct pressurization methods that are commonly used by many practitioners and the DeltaQ technique. These are methods B, C and A, respectively of the ASTM E1554 standard. Although it would be useful to evaluate other duct leak test methods, this study focused on those test methods that are commonly used and are required in various test standards, such as BPI (2010), RESNET (2014), ASHRAE 62.2 (2013), California Title 24 (CEC 2012), DOE Weatherization and many other energy efficiency programs.« less

Alternative Confidence Interval Methods Used in the Diagnostic Accuracy Studies

PubMed Central

Gülhan, Orekıcı Temel

2016-01-01

Background/Aim. It is necessary to decide whether the newly improved methods are better than the standard or reference test or not. To decide whether the new diagnostics test is better than the gold standard test/imperfect standard test, the differences of estimated sensitivity/specificity are calculated with the help of information obtained from samples. However, to generalize this value to the population, it should be given with the confidence intervals. The aim of this study is to evaluate the confidence interval methods developed for the differences between the two dependent sensitivity/specificity values on a clinical application. Materials and Methods. In this study, confidence interval methods like Asymptotic Intervals, Conditional Intervals, Unconditional Interval, Score Intervals, and Nonparametric Methods Based on Relative Effects Intervals are used. Besides, as clinical application, data used in diagnostics study by Dickel et al. (2010) has been taken as a sample. Results. The results belonging to the alternative confidence interval methods for Nickel Sulfate, Potassium Dichromate, and Lanolin Alcohol are given as a table. Conclusion. While preferring the confidence interval methods, the researchers have to consider whether the case to be compared is single ratio or dependent binary ratio differences, the correlation coefficient between the rates in two dependent ratios and the sample sizes. PMID:27478491

Alternative Confidence Interval Methods Used in the Diagnostic Accuracy Studies.

PubMed

Erdoğan, Semra; Gülhan, Orekıcı Temel

2016-01-01

Background/Aim. It is necessary to decide whether the newly improved methods are better than the standard or reference test or not. To decide whether the new diagnostics test is better than the gold standard test/imperfect standard test, the differences of estimated sensitivity/specificity are calculated with the help of information obtained from samples. However, to generalize this value to the population, it should be given with the confidence intervals. The aim of this study is to evaluate the confidence interval methods developed for the differences between the two dependent sensitivity/specificity values on a clinical application. Materials and Methods. In this study, confidence interval methods like Asymptotic Intervals, Conditional Intervals, Unconditional Interval, Score Intervals, and Nonparametric Methods Based on Relative Effects Intervals are used. Besides, as clinical application, data used in diagnostics study by Dickel et al. (2010) has been taken as a sample. Results. The results belonging to the alternative confidence interval methods for Nickel Sulfate, Potassium Dichromate, and Lanolin Alcohol are given as a table. Conclusion. While preferring the confidence interval methods, the researchers have to consider whether the case to be compared is single ratio or dependent binary ratio differences, the correlation coefficient between the rates in two dependent ratios and the sample sizes.

An efficient genome-wide association test for mixed binary and continuous phenotypes with applications to substance abuse research.

PubMed

Buu, Anne; Williams, L Keoki; Yang, James J

2018-03-01

We propose a new genome-wide association test for mixed binary and continuous phenotypes that uses an efficient numerical method to estimate the empirical distribution of the Fisher's combination statistic under the null hypothesis. Our simulation study shows that the proposed method controls the type I error rate and also maintains its power at the level of the permutation method. More importantly, the computational efficiency of the proposed method is much higher than the one of the permutation method. The simulation results also indicate that the power of the test increases when the genetic effect increases, the minor allele frequency increases, and the correlation between responses decreases. The statistical analysis on the database of the Study of Addiction: Genetics and Environment demonstrates that the proposed method combining multiple phenotypes can increase the power of identifying markers that may not be, otherwise, chosen using marginal tests.

Testing Faith: A Mixed Methods Study Investigating the Relationship between Prayer and Test Anxiety amongst College Students

ERIC Educational Resources Information Center

Campbell, Drey

2016-01-01

Test anxiety is problem that affects college students. Explanatory mixed methods research was completed with the objective of understanding the interrelationship of prayer and test anxiety as well as the potential therapeutic effects of Christian prayer on test anxiety. It was hypothesized that Christian prayer would have significant effects on…

Outcomes Definitions and Statistical Tests in Oncology Studies: A Systematic Review of the Reporting Consistency.

PubMed

Rivoirard, Romain; Duplay, Vianney; Oriol, Mathieu; Tinquaut, Fabien; Chauvin, Franck; Magne, Nicolas; Bourmaud, Aurelie

2016-01-01

Quality of reporting for Randomized Clinical Trials (RCTs) in oncology was analyzed in several systematic reviews, but, in this setting, there is paucity of data for the outcomes definitions and consistency of reporting for statistical tests in RCTs and Observational Studies (OBS). The objective of this review was to describe those two reporting aspects, for OBS and RCTs in oncology. From a list of 19 medical journals, three were retained for analysis, after a random selection: British Medical Journal (BMJ), Annals of Oncology (AoO) and British Journal of Cancer (BJC). All original articles published between March 2009 and March 2014 were screened. Only studies whose main outcome was accompanied by a corresponding statistical test were included in the analysis. Studies based on censored data were excluded. Primary outcome was to assess quality of reporting for description of primary outcome measure in RCTs and of variables of interest in OBS. A logistic regression was performed to identify covariates of studies potentially associated with concordance of tests between Methods and Results parts. 826 studies were included in the review, and 698 were OBS. Variables were described in Methods section for all OBS studies and primary endpoint was clearly detailed in Methods section for 109 RCTs (85.2%). 295 OBS (42.2%) and 43 RCTs (33.6%) had perfect agreement for reported statistical test between Methods and Results parts. In multivariable analysis, variable "number of included patients in study" was associated with test consistency: aOR (adjusted Odds Ratio) for third group compared to first group was equal to: aOR Grp3 = 0.52 [0.31-0.89] (P value = 0.009). Variables in OBS and primary endpoint in RCTs are reported and described with a high frequency. However, statistical tests consistency between methods and Results sections of OBS is not always noted. Therefore, we encourage authors and peer reviewers to verify consistency of statistical tests in oncology studies.

A Note on Testing Mediated Effects in Structural Equation Models: Reconciling Past and Current Research on the Performance of the Test of Joint Significance

ERIC Educational Resources Information Center

Valente, Matthew J.; Gonzalez, Oscar; Miocevic, Milica; MacKinnon, David P.

2016-01-01

Methods to assess the significance of mediated effects in education and the social sciences are well studied and fall into two categories: single sample methods and computer-intensive methods. A popular single sample method to detect the significance of the mediated effect is the test of joint significance, and a popular computer-intensive method…

Three methods to construct predictive models using logistic regression and likelihood ratios to facilitate adjustment for pretest probability give similar results.

PubMed

Chan, Siew Foong; Deeks, Jonathan J; Macaskill, Petra; Irwig, Les

2008-01-01

To compare three predictive models based on logistic regression to estimate adjusted likelihood ratios allowing for interdependency between diagnostic variables (tests). This study was a review of the theoretical basis, assumptions, and limitations of published models; and a statistical extension of methods and application to a case study of the diagnosis of obstructive airways disease based on history and clinical examination. Albert's method includes an offset term to estimate an adjusted likelihood ratio for combinations of tests. Spiegelhalter and Knill-Jones method uses the unadjusted likelihood ratio for each test as a predictor and computes shrinkage factors to allow for interdependence. Knottnerus' method differs from the other methods because it requires sequencing of tests, which limits its application to situations where there are few tests and substantial data. Although parameter estimates differed between the models, predicted "posttest" probabilities were generally similar. Construction of predictive models using logistic regression is preferred to the independence Bayes' approach when it is important to adjust for dependency of tests errors. Methods to estimate adjusted likelihood ratios from predictive models should be considered in preference to a standard logistic regression model to facilitate ease of interpretation and application. Albert's method provides the most straightforward approach.

[Alternatives to animal testing].

PubMed

Fabre, Isabelle

2009-11-01

The use of alternative methods to animal testing are an integral part of the 3Rs concept (refine, reduce, replace) defined by Russel & Burch in 1959. These approaches include in silico methods (databases and computer models), in vitro physicochemical analysis, biological methods using bacteria or isolated cells, reconstructed enzyme systems, and reconstructed tissues. Emerging "omic" methods used in integrated approaches further help to reduce animal use, while stem cells offer promising approaches to toxicologic and pathophysiologic studies, along with organotypic cultures and bio-artificial organs. Only a few alternative methods can so far be used in stand-alone tests as substitutes for animal testing. The best way to use these methods is to integrate them in tiered testing strategies (ITS), in which animals are only used as a last resort.

Practical Applications of a Building Method to Construct Aerodynamic Database of Guided Missile Using Wind Tunnel Test Data

NASA Astrophysics Data System (ADS)

Kim, Duk-hyun; Lee, Hyoung-Jin

2018-04-01

A study of efficient aerodynamic database modeling method was conducted. A creation of database using periodicity and symmetry characteristic of missile aerodynamic coefficient was investigated to minimize the number of wind tunnel test cases. In addition, studies of how to generate the aerodynamic database when the periodicity changes due to installation of protuberance and how to conduct a zero calibration were carried out. Depending on missile configurations, the required number of test cases changes and there exist tests that can be omitted. A database of aerodynamic on deflection angle of control surface can be constituted using phase shift. A validity of modeling method was demonstrated by confirming that the result which the aerodynamic coefficient calculated by using the modeling method was in agreement with wind tunnel test results.

Modification to the AOAC Sporicidal Activity of Disinfectants Test (Method 966.04): collaborative study.

PubMed

Tomasino, Stephen F; Hamilton, Martin A

2006-01-01

In an effort to improve AOAC Method 966.04, the Sporicidal Activity of Disinfectants Test, selected modifications to the procedure were evaluated in a collaborative study. Method 966.04 is used to generate efficacy data to support the product registration of sporicides and sterilants. The method is a carrier-based test that provides a qualitative measure of product efficacy against spores of Bacillus subtilis and Clostridium sporogenes. The use of garden soil extract and the lack of standard procedures for the enumeration of spores and neutralization of the test chemicals have been considered problematic for many years. The proposed modifications were limited to the B. subtilis and hard surface carrier (porcelain penicylinder) components of the method. The study included the evaluation of a replacement for soil extract nutrient broth and an establishment of a minimum spore titer per carrier, both considered crucial for the improvement and utilization of the method. Additionally, an alternative hard surface material and a neutralization confirmation procedure were evaluated. To determine the equivalence of the proposed alternatives to the standard method, 3 medium/carrier combinations, (1) soil extract nutrient broth/porcelain carrier (current method), (2) nutrient agar amended with 5 microg/mL manganese sulfate/porcelain carrier, and (3) nutrient agar amended with 5 microg/mL manganese sulfate/stainless steel carrier were analyzed for carrier counts, HCI resistance, efficacy, quantitative efficacy, and spore wash-off. The test chemicals used in the study represent 3 chemical classes and are commercially available antimicrobial liquid products: sodium hypochlorite (bleach), glutaraldehyde, and a combination of peracetic acid and hydrogen peroxide. Four laboratories participated in the study. The results of the spore titer per carrier, HCI resistance, efficacy, and wash-off studies demonstrate that amended nutrient agar in conjunction with the porcelain is comparable to the current method, soil extract nutrient broth/porcelain. The nutrient agar method is simple, inexpensive, reproducible, and provides an ample supply of high quality spores. Due to the current use of porcelain carriers for testing C. sporogenes, it is advisable to retain the use of porcelain carriers until stainless steel can be evaluated as a replacement carrier material for Clostridium. The evaluation of stainless steel for Clostridium has been initiated by the Study Director. Study Director recommendations for First Action revisions are provided in a modified method.

[Do different interpretative methods used for evaluation of checkerboard synergy test affect the results?].

PubMed

Ozseven, Ayşe Gül; Sesli Çetin, Emel; Ozseven, Levent

2012-07-01

In recent years, owing to the presence of multi-drug resistant nosocomial bacteria, combination therapies are more frequently applied. Thus there is more need to investigate the in vitro activity of drug combinations against multi-drug resistant bacteria. Checkerboard synergy testing is among the most widely used standard technique to determine the activity of antibiotic combinations. It is based on microdilution susceptibility testing of antibiotic combinations. Although this test has a standardised procedure, there are many different methods for interpreting the results. In many previous studies carried out with multi-drug resistant bacteria, different rates of synergy have been reported with various antibiotic combinations using checkerboard technique. These differences might be attributed to the different features of the strains. However, different synergy rates detected by checkerboard method have also been reported in other studies using the same drug combinations and same types of bacteria. It was thought that these differences in synergy rates might be due to the different methods of interpretation of synergy test results. In recent years, multi-drug resistant Acinetobacter baumannii has been the most commonly encountered nosocomial pathogen especially in intensive-care units. For this reason, multidrug resistant A.baumannii has been the subject of a considerable amount of research about antimicrobial combinations. In the present study, the in vitro activities of frequently preferred combinations in A.baumannii infections like imipenem plus ampicillin/sulbactam, and meropenem plus ampicillin/sulbactam were tested by checkerboard synergy method against 34 multi-drug resistant A.baumannii isolates. Minimum inhibitory concentration (MIC) values for imipenem, meropenem and ampicillin/sulbactam were determined by the broth microdilution method. Subsequently the activity of two different combinations were tested in the dilution range of 4 x MIC and 0.03 x MIC in 96-well checkerboard plates. The results were obtained separately using the four different interpretation methods frequently preferred by researchers. Thus, it was aimed to detect to what extent the rates of synergistic, indifferent and antagonistic interactions were affected by different interpretation methods. The differences between the interpretation methods were tested by chi-square analysis for each combination used. Statistically significant differences were detected between the four different interpretation methods for the determination of synergistic and indifferent interactions (p< 0.0001). Highest rates of synergy were observed with both combinations by the method that used the lowest fractional inhibitory concentration index of all the non-turbid wells along the turbidity/non-turbidity interface. There was no statistically significant difference between the four methods for the detection of antagonism (p> 0.05). In conclusion although there is a standard procedure for checkerboard synergy testing it fails to exhibit standard results owing to different methods of interpretation of the results. Thus, there is a need to standardise the interpretation method for checkerboard synergy testing. To determine the most appropriate method of interpretation further studies investigating the clinical benefits of synergic combinations and additionally comparing the consistency of the results obtained from the other standard combination tests like time-kill studies, are required.

Comparative evaluation of two quantitative test methods for determining the efficacy of liquid sporicides and sterilants on a hard surface: a precollaborative study.

PubMed

Tomasino, Stephen F; Hamilton, Martin A

2007-01-01

Two quantitative carrier-based test methods for determining the efficacy of liquid sporicides and sterilants on a hard surface, the Standard Quantitative Carrier Test Method-ASTM E 2111-00 and an adaptation of a quantitative micro-method as reported by Sagripanti and Bonifacino, were compared in this study. The methods were selected based on their desirable characteristics (e.g., well-developed protocol, previous use with spores, fully quantitative, and use of readily available equipment) for testing liquid sporicides and sterilants on a hard surface. In this paper, the Sagripanti-Bonifacino procedure is referred to as the Three Step Method (TSM). AOAC Official Method 966.04 was included in this study as a reference method. Three laboratories participated in the evaluation. Three chemical treatments were tested: (1) 3000 ppm sodium hypochlorite with pH adjusted to 7.0, (2) a hydrogen peroxide/peroxyacetic acid product, and (3) 3000 ppm sodium hypochlorite with pH unadjusted (pH of approximately 10.0). A fourth treatment, 6000 ppm sodium hypochlorite solution with pH adjusted to 7.0, was included only for Method 966.04 as a positive control (high level of efficacy). The contact time was 10 min for all chemical treatments except the 6000 ppm sodium hypochlorite treatment which was tested at 30 min. Each chemical treatment was tested 3 times using each of the methods. Only 2 of the laboratories performed the AOAC method. Method performance was assessed by the within-laboratory variance, between-laboratory variance, and total variance associated with the log reduction (LR) estimates generated by each quantitative method. The quantitative methods performed similarly, and the LR values generated by each method were not statistically different for the 3 treatments evaluated. Based on feedback from the participating laboratories, compared to the TSM, ASTM E 2111-00 was more resource demanding and required more set-up time. The logistical and resource concerns identified for ASTM E 2111-00 were largely associated with the filtration process and counting bacterial colonies on filters. Thus, the TSM was determined to be the most suitable method.

Final Report, Volume 2, The Development of Qualification Standards for Cast Duplex Stainless Steel

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

Russell, Steven, W.; Lundin, Carl, W.

2005-09-30

The scope of testing cast Duplex Stainless Steel (DSS) required testing to several ASTM specifications, while formulating and conducting industry round robin tests to verify and study the reproducibility of the results. ASTM E562 (Standard Test Method for Determining Volume Fraction by Systematic manual Point Count) and ASTM A923 (Standard Test Methods for Detecting Detrimental Intermetallic Phase in Wrought Duplex Austenitic/Ferritic Stainless Steels) were the specifications utilized in conducting this work. An ASTM E562 industry round robin, ASTM A923 applicability study, ASTM A923 industry round robin, and an ASTM A923 study of the effectiveness of existing foundry solution annealing proceduresmore » for producing cast DSS without intermetallic phases were implemented. In the ASTM E562 study, 5 samples were extracted from various cast austenitic and DSS in order to have varying amounts of ferrite. Each sample was metallographically prepared by UT and sent to each of 8 participants for volume fraction of ferrite measurements. Volume fraction of ferrite was measured using manual point count per ASTM E562. FN was measured from the Feritescope® and converted to volume fraction of ferrite. Results indicate that ASTM E562 is applicable to DSS and the results have excellent lab-to-lab reproducibility. Also, volume fraction of ferrite conversions from the FN measured by the Feritescope® were similar to volume fraction of ferrite measured per ASTM E562. In the ASTM A923 applicability to cast DSS study, 8 different heat treatments were performed on 3 lots of ASTM A890-4A (CD3MN) castings and 1 lot of 2205 wrought DSS. The heat treatments were selected to produce a wide range of cooling rates and hold times in order to study the suitability of ASTM A923 to the response of varying amounts on intermetallic phases [117]. The test parameters were identical to those used to develop ASTM A923 for wrought DSS. Charpy V-notch impact samples were extracted from the castings and wrought DSS and tested per ASTM A923 method B (Charpy impact test). Method A (sodium hydroxide etch test) was performed on one half of a fractured Charpy V-notch impact sample and Method C (ferric chloride corrosion weight loss test) was performed on another half. Test results for the three cast lots and one wrought lot indicate that ASTM A923 is relevant for detecting intermetallic phases in cast DSS. In the ASTM A923 round robin study, five laboratories conducted ASTM A923 Methods A & C on cast DSS material and the lab-to-lab reproducibility of the data was determined. Two groups of samples were sent to the participants. Group 1 samples were tested per ASTM A923 Method A, group 2 samples were tested by ASTM A923 Method C. Testing procedures for this round robin study were identical to those used in the ASTM A923 applicability study. Results from this round robin indicate that there is excellent lab-to-lab reproducibility of ASTM A923 with respect to cast DSS and that ASTM A923 could be expanded to cover both wrought and cast DSS. In the ASTM A923 study of the effectiveness of existing foundry solution annealing procedures for producing cast DSS without intermetallic phases, Ten heats of ASTM A890-4A (CD3MN) in the foundry solution annealed condition were tested per ASTM A923 Methods A, B, & C. Testing of these materials per ASTM A923 was used to determine if the foundry solution anneal procedures were adequate to completely eliminate any intermetallic phases, which may have precipitated during the casting and subsequent heat treatment processes. All heats showed no sign of intermetallic phase per Method A, passed minimum Charpy impact energy requirements per Method B (> 40 ft-lbs @ -40°C (-40°F)), and showed negligible weight loss per Method C (< 10 mdd). These results indicate that the solution annealing procedure used by foundries is adequate to produce a product free from intermetallic phases.« less

Final Report, Volume 2, The Development of Qualification Standards for Cast Duplex Stainless Steel

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

Russell, Steven, W.; Lundin, Carl, D.

2005-09-30

The scope of testing cast Duplex Stainless Steel (DSS) required testing to several ASTM specifications, while formulating and conducting industry round robin tests to verify and study the reproducibility of the results. ASTM E562 (Standard Test Method for Determining Volume Fraction by Systematic manual Point Count) and ASTM A923 (Standard Test Methods for Detecting Detrimental Intermetallic Phase in Wrought Duplex Austenitic/Ferritic Stainless Steels) were the specifications utilized in conducting this work. An ASTM E562 industry round robin, ASTM A923 applicability study, ASTM A923 industry round robin, and an ASTM A923 study of the effectiveness of existing foundry solution annealing proceduresmore » for producing cast DSS without intermetallic phases were implemented. In the ASTM E562 study, 5 samples were extracted from various cast austenitic and DSS in order to have varying amounts of ferrite. Each sample was metallographically prepared by UT and sent to each of 8 participants for volume fraction of ferrite measurements. Volume fraction of ferrite was measured using manual point count per ASTM E562. FN was measured from the Feritescope{reg_sign} and converted to volume fraction of ferrite. Results indicate that ASTM E562 is applicable to DSS and the results have excellent lab-to-lab reproducibility. Also, volume fraction of ferrite conversions from the FN measured by the Feritescope{reg_sign} were similar to volume fraction of ferrite measured per ASTM E562. In the ASTM A923 applicability to cast DSS study, 8 different heat treatments were performed on 3 lots of ASTM A890-4A (CD3MN) castings and 1 lot of 2205 wrought DSS. The heat treatments were selected to produce a wide range of cooling rates and hold times in order to study the suitability of ASTM A923 to the response of varying amounts on intermetallic phases [117]. The test parameters were identical to those used to develop ASTM A923 for wrought DSS. Charpy V-notch impact samples were extracted from the castings and wrought DSS and tested per ASTM A923 method B (Charpy impact test). Method A (sodium hydroxide etch test) was performed on one half of a fractured Charpy V-notch impact sample and Method C (ferric chloride corrosion weight loss test) was performed on another half. Test results for the three cast lots and one wrought lot indicate that ASTM A923 is relevant for detecting intermetallic phases in cast DSS. In the ASTM A923 round robin study, five laboratories conducted ASTM A923 Methods A & C on cast DSS material and the lab-to-lab reproducibility of the data was determined. Two groups of samples were sent to the participants. Group 1 samples were tested per ASTM A923 Method A, group 2 samples were tested by ASTM A923 Method C. Testing procedures for this round robin study were identical to those used in the ASTM A923 applicability study. Results from this round robin indicate that there is excellent lab-to-lab reproducibility of ASTM A923 with respect to cast DSS and that ASTM A923 could be expanded to cover both wrought and cast DSS. In the ASTM A923 study of the effectiveness of existing foundry solution annealing procedures for producing cast DSS without intermetallic phases, Ten heats of ASTM A890-4A (CD3MN) in the foundry solution annealed condition were tested per ASTM A923 Methods A, B, & C. Testing of these materials per ASTM A923 was used to determine if the foundry solution anneal procedures were adequate to completely eliminate any intermetallic phases, which may have precipitated during the casting and subsequent heat treatment processes. All heats showed no sign of intermetallic phase per Method A, passed minimum Charpy impact energy requirements per Method B (> 40 ft-lbs {at} -40 C (-40 F)), and showed negligible weight loss per Method C (< 10 mdd). These results indicate that the solution annealing procedure used by foundries is adequate to produce a product free from intermetallic phases.« less

Systematic Review of Health Economic Evaluations of Diagnostic Tests in Brazil: How accurate are the results?

PubMed

Oliveira, Maria Regina Fernandes; Leandro, Roseli; Decimoni, Tassia Cristina; Rozman, Luciana Martins; Novaes, Hillegonda Maria Dutilh; De Soárez, Patrícia Coelho

2017-08-01

The aim of this study is to identify and characterize the health economic evaluations (HEEs) of diagnostic tests conducted in Brazil, in terms of their adherence to international guidelines for reporting economic studies and specific questions in test accuracy reports. We systematically searched multiple databases, selecting partial and full HEEs of diagnostic tests, published between 1980 and 2013. Two independent reviewers screened articles for relevance and extracted the data. We performed a qualitative narrative synthesis. Forty-three articles were reviewed. The most frequently studied diagnostic tests were laboratory tests (37.2%) and imaging tests (32.6%). Most were non-invasive tests (51.2%) and were performed in the adult population (48.8%). The intended purposes of the technologies evaluated were mostly diagnostic (69.8%), but diagnosis and treatment and screening, diagnosis, and treatment accounted for 25.6% and 4.7%, respectively. Of the reviewed studies, 12.5% described the methods used to estimate the quantities of resources, 33.3% reported the discount rate applied, and 29.2% listed the type of sensitivity analysis performed. Among the 12 cost-effectiveness analyses, only two studies (17%) referred to the application of formal methods to check the quality of the accuracy studies that provided support for the economic model. The existing Brazilian literature on the HEEs of diagnostic tests exhibited reasonably good performance. However, the following points still require improvement: 1) the methods used to estimate resource quantities and unit costs, 2) the discount rate, 3) descriptions of sensitivity analysis methods, 4) reporting of conflicts of interest, 5) evaluations of the quality of the accuracy studies considered in the cost-effectiveness models, and 6) the incorporation of accuracy measures into sensitivity analyses.

Testing high SPF sunscreens: a demonstration of the accuracy and reproducibility of the results of testing high SPF formulations by two methods and at different testing sites.

PubMed

Agin, Patricia Poh; Edmonds, Susan H

2002-08-01

The goals of this study were (i) to demonstrate that existing and widely used sun protection factor (SPF) test methodologies can produce accurate and reproducible results for high SPF formulations and (ii) to provide data on the number of test-subjects needed, the variability of the data, and the appropriate exposure increments needed for testing high SPF formulations. Three high SPF formulations were tested, according to the Food and Drug Administration's (FDA) 1993 tentative final monograph (TFM) 'very water resistant' test method and/or the 1978 proposed monograph 'waterproof' test method, within one laboratory. A fourth high SPF formulation was tested at four independent SPF testing laboratories, using the 1978 waterproof SPF test method. All laboratories utilized xenon arc solar simulators. The data illustrate that the testing conducted within one laboratory, following either the 1978 proposed or the 1993 TFM SPF test method, was able to reproducibly determine the SPFs of the formulations tested, using either the statistical analysis method in the proposed monograph or the statistical method described in the TFM. When one formulation was tested at four different laboratories, the anticipated variation in the data owing to the equipment and other operational differences was minimized through the use of the statistical method described in the 1993 monograph. The data illustrate that either the 1978 proposed monograph SPF test method or the 1993 TFM SPF test method can provide accurate and reproducible results for high SPF formulations. Further, these results can be achieved with panels of 20-25 subjects with an acceptable level of variability. Utilization of the statistical controls from the 1993 sunscreen monograph can help to minimize lab-to-lab variability for well-formulated products.

Experimental Evaluation of Suitability of Selected Multi-Criteria Decision-Making Methods for Large-Scale Agent-Based Simulations.

PubMed

Tučník, Petr; Bureš, Vladimír

2016-01-01

Multi-criteria decision-making (MCDM) can be formally implemented by various methods. This study compares suitability of four selected MCDM methods, namely WPM, TOPSIS, VIKOR, and PROMETHEE, for future applications in agent-based computational economic (ACE) models of larger scale (i.e., over 10 000 agents in one geographical region). These four MCDM methods were selected according to their appropriateness for computational processing in ACE applications. Tests of the selected methods were conducted on four hardware configurations. For each method, 100 tests were performed, which represented one testing iteration. With four testing iterations conducted on each hardware setting and separated testing of all configurations with the-server parameter de/activated, altogether, 12800 data points were collected and consequently analyzed. An illustrational decision-making scenario was used which allows the mutual comparison of all of the selected decision making methods. Our test results suggest that although all methods are convenient and can be used in practice, the VIKOR method accomplished the tests with the best results and thus can be recommended as the most suitable for simulations of large-scale agent-based models.

Spread Spectrum Receiver Electromagnetic Interference (EMI) Test Guide

NASA Technical Reports Server (NTRS)

Wheeler, M. L.

1998-01-01

The objective of this test guide is to document appropriate unit level test methods and techniques for the performance of EMI testing of Direct Sequence (DS) spread spectrum receivers. Consideration of EMI test methods tailored for spread spectrum receivers utilizing frequency spreading, techniques other than direct sequence (such as frequency hopping, frequency chirping, and various hybrid methods) is beyond the scope of this test guide development program and is not addressed as part of this document EMI test requirements for NASA programs are primarily developed based on the requirements contained in MIL-STD-46 1 D (or earlier revisions of MIL-STD-46 1). The corresponding test method guidelines for the MIL-STD-461 D tests are provided in MIL-STD-462D. These test methods are well documented with the exception of the receiver antenna port susceptibility tests (intermodulation, cross modulation, and rejection of undesired signals) which must be tailored to the specific type of receiver that is being tested. Thus, test methods addressed in this guide consist only of antenna port tests designed to evaluate receiver susceptibility characteristics. MIL-STD-462D should be referred for guidance pertaining to test methods for EMI tests other than the antenna port tests. The scope of this test guide includes: (1) a discussion of generic DS receiver performance characteristics; (2) a summary of S-band TDRSS receiver operation; (3) a discussion of DS receiver EMI susceptibility mechanisms and characteristics; (4) a summary of military standard test guidelines; (5) recommended test approach and methods; and (6) general conclusions and recommendations for future studies in the area of spread spectrum receiver testing.

Repeatability study of replicate crash tests: A signal analysis approach.

PubMed

Seppi, Jeremy; Toczyski, Jacek; Crandall, Jeff R; Kerrigan, Jason

2017-10-03

To provide an objective basis on which to evaluate the repeatability of vehicle crash test methods, a recently developed signal analysis method was used to evaluate correlation of sensor time history data between replicate vehicle crash tests. The goal of this study was to evaluate the repeatability of rollover crash tests performed with the Dynamic Rollover Test System (DRoTS) relative to other vehicle crash test methods. Test data from DRoTS tests, deceleration rollover sled (DRS) tests, frontal crash tests, frontal offset crash tests, small overlap crash tests, small overlap impact (SOI) crash tests, and oblique crash tests were obtained from the literature and publicly available databases (the NHTSA vehicle database and the Insurance Institute for Highway Safety TechData) to examine crash test repeatability. Signal analysis of the DRoTS tests showed that force and deformation time histories had good to excellent repeatability, whereas vehicle kinematics showed only fair repeatability due to the vehicle mounting method for one pair of tests and slightly dissimilar mass properties (2.2%) in a second pair of tests. Relative to the DRS, the DRoTS tests showed very similar or higher levels of repeatability in nearly all vehicle kinematic data signals with the exception of global X' (road direction of travel) velocity and displacement due to the functionality of the DRoTS fixture. Based on the average overall scoring metric of the dominant acceleration, DRoTS was found to be as repeatable as all other crash tests analyzed. Vertical force measures showed good repeatability and were on par with frontal crash barrier forces. Dynamic deformation measures showed good to excellent repeatability as opposed to poor repeatability seen in SOI and oblique deformation measures. Using the signal analysis method as outlined in this article, the DRoTS was shown to have the same or better repeatability of crash test methods used in government regulatory and consumer evaluation test protocols.

Effects of Problem-Solving Method on Secondary School Students' Achievement and Retention in Social Studies, in Ekiti State, Nigeria

ERIC Educational Resources Information Center

Abdu-Raheem, B. O.

2012-01-01

This study investigated the effects of problem-solving method of teaching on secondary school students' achievement and retention in Social Studies. The study adopted the quasi-experimental, pre-test, post-test, control group design. The sample for the study consisted of 240 Junior Secondary School Class II students randomly selected from six…

MicroSEQ® Salmonella spp. Detection Kit Using the Pathatrix® 10-Pooling Salmonella spp. Kit Linked Protocol Method Modification.

PubMed

Wall, Jason; Conrad, Rick; Latham, Kathy; Liu, Eric

2014-03-01

Real-time PCR methods for detecting foodborne pathogens offer the advantages of simplicity and quick time to results compared to traditional culture methods. The addition of a recirculating pooled immunomagnetic separation method prior to real-time PCR analysis increases processing output while reducing both cost and labor. This AOAC Research Institute method modification study validates the MicroSEQ® Salmonella spp. Detection Kit [AOAC Performance Tested Method (PTM) 031001] linked with the Pathatrix® 10-Pooling Salmonella spp. Kit (AOAC PTM 090203C) in diced tomatoes, chocolate, and deli ham. The Pathatrix 10-Pooling protocol represents a method modification of the enrichment portion of the MicroSEQ Salmonella spp. The results of the method modification were compared to standard cultural reference methods for diced tomatoes, chocolate, and deli ham. All three matrixes were analyzed in a paired study design. An additional set of chocolate test portions was analyzed using an alternative enrichment medium in an unpaired study design. For all matrixes tested, there were no statistically significant differences in the number of positive test portions detected by the modified candidate method compared to the appropriate reference method. The MicroSEQ Salmonella spp. protocol linked with the Pathatrix individual or 10-Pooling procedure demonstrated reliability as a rapid, simplified, method for the preparation of samples and subsequent detection of Salmonella in diced tomatoes, chocolate, and deli ham.

Gene-Based Testing of Interactions in Association Studies of Quantitative Traits

PubMed Central

Ma, Li; Clark, Andrew G.; Keinan, Alon

2013-01-01

Various methods have been developed for identifying gene–gene interactions in genome-wide association studies (GWAS). However, most methods focus on individual markers as the testing unit, and the large number of such tests drastically erodes statistical power. In this study, we propose novel interaction tests of quantitative traits that are gene-based and that confer advantage in both statistical power and biological interpretation. The framework of gene-based gene–gene interaction (GGG) tests combine marker-based interaction tests between all pairs of markers in two genes to produce a gene-level test for interaction between the two. The tests are based on an analytical formula we derive for the correlation between marker-based interaction tests due to linkage disequilibrium. We propose four GGG tests that extend the following P value combining methods: minimum P value, extended Simes procedure, truncated tail strength, and truncated P value product. Extensive simulations point to correct type I error rates of all tests and show that the two truncated tests are more powerful than the other tests in cases of markers involved in the underlying interaction not being directly genotyped and in cases of multiple underlying interactions. We applied our tests to pairs of genes that exhibit a protein–protein interaction to test for gene-level interactions underlying lipid levels using genotype data from the Atherosclerosis Risk in Communities study. We identified five novel interactions that are not evident from marker-based interaction testing and successfully replicated one of these interactions, between SMAD3 and NEDD9, in an independent sample from the Multi-Ethnic Study of Atherosclerosis. We conclude that our GGG tests show improved power to identify gene-level interactions in existing, as well as emerging, association studies. PMID:23468652

Data entry errors and design for model-based tight glycemic control in critical care.

PubMed

Ward, Logan; Steel, James; Le Compte, Aaron; Evans, Alicia; Tan, Chia-Siong; Penning, Sophie; Shaw, Geoffrey M; Desaive, Thomas; Chase, J Geoffrey

2012-01-01

Tight glycemic control (TGC) has shown benefits but has been difficult to achieve consistently. Model-based methods and computerized protocols offer the opportunity to improve TGC quality but require human data entry, particularly of blood glucose (BG) values, which can be significantly prone to error. This study presents the design and optimization of data entry methods to minimize error for a computerized and model-based TGC method prior to pilot clinical trials. To minimize data entry error, two tests were carried out to optimize a method with errors less than the 5%-plus reported in other studies. Four initial methods were tested on 40 subjects in random order, and the best two were tested more rigorously on 34 subjects. The tests measured entry speed and accuracy. Errors were reported as corrected and uncorrected errors, with the sum comprising a total error rate. The first set of tests used randomly selected values, while the second set used the same values for all subjects to allow comparisons across users and direct assessment of the magnitude of errors. These research tests were approved by the University of Canterbury Ethics Committee. The final data entry method tested reduced errors to less than 1-2%, a 60-80% reduction from reported values. The magnitude of errors was clinically significant and was typically by 10.0 mmol/liter or an order of magnitude but only for extreme values of BG < 2.0 mmol/liter or BG > 15.0-20.0 mmol/liter, both of which could be easily corrected with automated checking of extreme values for safety. The data entry method selected significantly reduced data entry errors in the limited design tests presented, and is in use on a clinical pilot TGC study. The overall approach and testing methods are easily performed and generalizable to other applications and protocols. © 2012 Diabetes Technology Society.

Using a fuzzy comprehensive evaluation method to determine product usability: A test case

PubMed Central

Zhou, Ronggang; Chan, Alan H. S.

2016-01-01

BACKGROUND: In order to take into account the inherent uncertainties during product usability evaluation, Zhou and Chan [1] proposed a comprehensive method of usability evaluation for products by combining the analytic hierarchy process (AHP) and fuzzy evaluation methods for synthesizing performance data and subjective response data. This method was designed to provide an integrated framework combining the inevitable vague judgments from the multiple stages of the product evaluation process. OBJECTIVE AND METHODS: In order to illustrate the effectiveness of the model, this study used a summative usability test case to assess the application and strength of the general fuzzy usability framework. To test the proposed fuzzy usability evaluation framework [1], a standard summative usability test was conducted to benchmark the overall usability of a specific network management software. Based on the test data, the fuzzy method was applied to incorporate both the usability scores and uncertainties involved in the multiple components of the evaluation. Then, with Monte Carlo simulation procedures, confidence intervals were used to compare the reliabilities among the fuzzy approach and two typical conventional methods combining metrics based on percentages. RESULTS AND CONCLUSIONS: This case study showed that the fuzzy evaluation technique can be applied successfully for combining summative usability testing data to achieve an overall usability quality for the network software evaluated. Greater differences of confidence interval widths between the method of averaging equally percentage and weighted evaluation method, including the method of weighted percentage averages, verified the strength of the fuzzy method. PMID:28035942

A study: Effect of Students Peer Assisted Learning on Magnetic Field Achievement

NASA Astrophysics Data System (ADS)

Mueanploy, Wannapa

2016-04-01

This study is the case study of Physic II Course for students of Pathumwan Institute of Technology. The purpose of this study is: 1) to develop cooperative learning method of peer assisted learning (PAL), 2) to compare the learning achievement before and after studied magnetic field lesson by cooperative learning method of peer assisted learning. The population was engineering students of Pathumwan Institute of Technology (PIT’s students) who registered Physic II Course during year 2014. The sample used in this study was selected from the 72 students who passed in Physic I Course. The control groups learning magnetic fields by Traditional Method (TM) and experimental groups learning magnetic field by method of peers assisted learning. The students do pretest before the lesson and do post-test after the lesson by 20 items achievement tests of magnetic field. The post-test higher than pretest achievement significantly at 0.01 level.

Study on AC loss measurements of HTS power cable for standardizing

NASA Astrophysics Data System (ADS)

Mukoyama, Shinichi; Amemiya, Naoyuki; Watanabe, Kazuo; Iijima, Yasuhiro; Mido, Nobuhiro; Masuda, Takao; Morimura, Toshiya; Oya, Masayoshi; Nakano, Tetsutaro; Yamamoto, Kiyoshi

2017-09-01

High-temperature superconducting power cables (HTS cables) have been developed for more than 20 years. In addition of the cable developments, the test methods of the HTS cables have been discussed and proposed in many laboratories and companies. Recently the test methods of the HTS cables is required to standardize and to common in the world. CIGRE made the working group (B1-31) for the discussion of the test methods of the HTS cables as a power cable, and published the recommendation of the test method. Additionally, IEC TC20 submitted the New Work Item Proposal (NP) based on the recommendation of CIGRE this year, IEC TC20 and IEC TC90 started the standardization work on Testing of HTS AC cables. However, the individual test method that used to measure a performance of HTS cables hasn’t been established as world’s common methods. The AC loss is one of the most important properties to disseminate low loss and economical efficient HTS cables in the world. We regard to establish the method of the AC loss measurements in rational and in high accuracy. Japan is at a leading position in the AC loss study, because Japanese researchers have studied on the AC loss technically and scientifically, and also developed the effective technologies for the AC loss reduction. The JP domestic commission of TC90 made a working team to discussion the methods of the AC loss measurements for aiming an international standard finally. This paper reports about the AC loss measurement of two type of the HTS conductors, such as a HTS conductor without a HTS shield and a HTS conductor with a HTS shield. The AC loss measurement method is suggested by the electrical method..

Develop a new testing and evaluation protocol to assess flexbase performance using strength of soil binder.

DOT National Transportation Integrated Search

2008-01-01

This research involved a detailed laboratory study of a new test method for evaluating road base materials based on : the strength of the soil binder. In this test method, small test specimens (5.0in length and 0.75in square cross : section) of binde...

Magic Finger Teaching Method in Learning Multiplication Facts among Deaf Students

ERIC Educational Resources Information Center

Thai, Liong; Yasin, Mohd. Hanafi Mohd

2016-01-01

Deaf students face problems in mastering multiplication facts. This study aims to identify the effectiveness of Magic Finger Teaching Method (MFTM) and students' perception towards MFTM. The research employs a quasi experimental with non-equivalent pre-test and post-test control group design. Pre-test, post-test and questionnaires were used. As…

The Development of MST Test Information for the Prediction of Test Performances

ERIC Educational Resources Information Center

Park, Ryoungsun; Kim, Jiseon; Chung, Hyewon; Dodd, Barbara G.

2017-01-01

The current study proposes novel methods to predict multistage testing (MST) performance without conducting simulations. This method, called MST test information, is based on analytic derivation of standard errors of ability estimates across theta levels. We compared standard errors derived analytically to the simulation results to demonstrate the…

Efficient Testing Combining Design of Experiment and Learn-to-Fly Strategies

NASA Technical Reports Server (NTRS)

Murphy, Patrick C.; Brandon, Jay M.

2017-01-01

Rapid modeling and efficient testing methods are important in a number of aerospace applications. In this study efficient testing strategies were evaluated in a wind tunnel test environment and combined to suggest a promising approach for both ground-based and flight-based experiments. Benefits of using Design of Experiment techniques, well established in scientific, military, and manufacturing applications are evaluated in combination with newly developing methods for global nonlinear modeling. The nonlinear modeling methods, referred to as Learn-to-Fly methods, utilize fuzzy logic and multivariate orthogonal function techniques that have been successfully demonstrated in flight test. The blended approach presented has a focus on experiment design and identifies a sequential testing process with clearly defined completion metrics that produce increased testing efficiency.

Methods for evaluating the biological impact of potentially toxic waste applied to soils

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

Neuhauser, E.F.; Loehr, R.C.; Malecki, M.R.

1985-12-01

The study was designed to evaluate two methods that can be used to estimate the biological impact of organics and inorganics that may be in wastes applied to land for treatment and disposal. The two methods were the contact test and the artificial soil test. The contact test is a 48 hr test using an adult worm, a small glass vial, and filter paper to which the test chemical or waste is applied. The test is designed to provide close contact between the worm and a chemical similar to the situation in soils. The method provides a rapid estimate ofmore » the relative toxicity of chemicals and industrial wastes. The artificial soil test uses a mixture of sand, kaolin, peat, and calcium carbonate as a representative soil. Different concentrations of the test material are added to the artificial soil, adult worms are added and worm survival is evaluated after two weeks. These studies have shown that: earthworms can distinguish between a wide variety of chemicals with a high degree of accuracy.« less

The effect of explanations on mathematical reasoning tasks

NASA Astrophysics Data System (ADS)

Norqvist, Mathias

2018-01-01

Studies in mathematics education often point to the necessity for students to engage in more cognitively demanding activities than just solving tasks by applying given solution methods. Previous studies have shown that students that engage in creative mathematically founded reasoning to construct a solution method, perform significantly better in follow up tests than students that are given a solution method and engage in algorithmic reasoning. However, teachers and textbooks, at least occasionally, provide explanations together with an algorithmic method, and this could possibly be more efficient than creative reasoning. In this study, three matched groups practiced with either creative, algorithmic, or explained algorithmic tasks. The main finding was that students that practiced with creative tasks did, outperform the students that practiced with explained algorithmic tasks in a post-test, despite a much lower practice score. The two groups that got a solution method presented, performed similarly in both practice and post-test, even though one group got an explanation to the given solution method. Additionally, there were some differences between the groups in which variables predicted the post-test score.

AFNOR validation of Premi Test, a microbiological-based screening tube-test for the detection of antimicrobial residues in animal muscle tissue.

PubMed

Gaudin, Valerie; Juhel-Gaugain, Murielle; Morétain, Jean-Pierre; Sanders, Pascal

2008-12-01

Premi Test contains viable spores of a strain of Bacillus stearothermophilus which is sensitive to antimicrobial residues, such as beta-lactams, tetracyclines, macrolides and sulphonamides. The growth of the strain is inhibited by the presence of antimicrobial residues in muscle tissue samples. Premi Test was validated according to AFNOR rules (French Association for Normalisation). The AFNOR validation was based on the comparison of reference methods (French Official method, i.e. four plate test (FPT) and the STAR protocol (five plate test)) with the alternative method (Premi Test). A preliminary study was conducted in an expert laboratory (Community Reference Laboratory, CRL) on both spiked and incurred samples (field samples). Several method performance criteria (sensitivity, specificity, relative accuracy) were estimated and are discussed, in addition to detection capabilities. Adequate agreement was found between the alternative method and the reference methods. However, Premi Test was more sensitive to beta-lactams and sulphonamides than the FPT. Subsequently, a collaborative study with 11 laboratories was organised by the CRL. Blank and spiked meat juice samples were sent to participants. The expert laboratory (CRL) statistically analysed the results. It was concluded that Premi Test could be used for the routine determination of antimicrobial residues in muscle of different animal origin with acceptable analytical performance. The detection capabilities of Premi Test for beta-lactams (amoxicillin, ceftiofur), one macrolide (tylosin) and tetracycline were at the level of the respective maximum residue limits (MRL) in muscle samples or even lower.

The Effects of Process Oriented Guided Inquiry Learning on Secondary Student ACT Science Scores

NASA Astrophysics Data System (ADS)

Judd, William Lindsey

The purpose of this study was to examine any significant difference on secondary school chemistry students' ACT Science Test scores between students taught by the Process Oriented Guided Inquiry Learning (POGIL) method versus students taught by traditional, teacher-centered pedagogy. This study also examined any difference between students taught by the POGIL method versus students taught by traditional, teacher-centered pedagogy in regard to the three different types of questions on the ACT Science Test: data representation, research summaries, and conflicting viewpoints. The sample consisted of sophomore-level students at two private, suburban Christian schools. A pretest-posttest design was used to compare the mean difference in scores from ACT issued sample test booklets before and after each group had received instruction via the POGIL method or more traditional methods. This study found that there was no significant difference in the mean difference of test scores between the two groups. This study also found that there was not a significant difference in the mean difference of scores in regard to the three different types of questions on the ACT Science Test. Further implications of this study are discussed.

An efficient genome-wide association test for multivariate phenotypes based on the Fisher combination function.

PubMed

Yang, James J; Li, Jia; Williams, L Keoki; Buu, Anne

2016-01-05

In genome-wide association studies (GWAS) for complex diseases, the association between a SNP and each phenotype is usually weak. Combining multiple related phenotypic traits can increase the power of gene search and thus is a practically important area that requires methodology work. This study provides a comprehensive review of existing methods for conducting GWAS on complex diseases with multiple phenotypes including the multivariate analysis of variance (MANOVA), the principal component analysis (PCA), the generalizing estimating equations (GEE), the trait-based association test involving the extended Simes procedure (TATES), and the classical Fisher combination test. We propose a new method that relaxes the unrealistic independence assumption of the classical Fisher combination test and is computationally efficient. To demonstrate applications of the proposed method, we also present the results of statistical analysis on the Study of Addiction: Genetics and Environment (SAGE) data. Our simulation study shows that the proposed method has higher power than existing methods while controlling for the type I error rate. The GEE and the classical Fisher combination test, on the other hand, do not control the type I error rate and thus are not recommended. In general, the power of the competing methods decreases as the correlation between phenotypes increases. All the methods tend to have lower power when the multivariate phenotypes come from long tailed distributions. The real data analysis also demonstrates that the proposed method allows us to compare the marginal results with the multivariate results and specify which SNPs are specific to a particular phenotype or contribute to the common construct. The proposed method outperforms existing methods in most settings and also has great applications in GWAS on complex diseases with multiple phenotypes such as the substance abuse disorders.

gsSKAT: Rapid gene set analysis and multiple testing correction for rare-variant association studies using weighted linear kernels.

PubMed

Larson, Nicholas B; McDonnell, Shannon; Cannon Albright, Lisa; Teerlink, Craig; Stanford, Janet; Ostrander, Elaine A; Isaacs, William B; Xu, Jianfeng; Cooney, Kathleen A; Lange, Ethan; Schleutker, Johanna; Carpten, John D; Powell, Isaac; Bailey-Wilson, Joan E; Cussenot, Olivier; Cancel-Tassin, Geraldine; Giles, Graham G; MacInnis, Robert J; Maier, Christiane; Whittemore, Alice S; Hsieh, Chih-Lin; Wiklund, Fredrik; Catalona, William J; Foulkes, William; Mandal, Diptasri; Eeles, Rosalind; Kote-Jarai, Zsofia; Ackerman, Michael J; Olson, Timothy M; Klein, Christopher J; Thibodeau, Stephen N; Schaid, Daniel J

2017-05-01

Next-generation sequencing technologies have afforded unprecedented characterization of low-frequency and rare genetic variation. Due to low power for single-variant testing, aggregative methods are commonly used to combine observed rare variation within a single gene. Causal variation may also aggregate across multiple genes within relevant biomolecular pathways. Kernel-machine regression and adaptive testing methods for aggregative rare-variant association testing have been demonstrated to be powerful approaches for pathway-level analysis, although these methods tend to be computationally intensive at high-variant dimensionality and require access to complete data. An additional analytical issue in scans of large pathway definition sets is multiple testing correction. Gene set definitions may exhibit substantial genic overlap, and the impact of the resultant correlation in test statistics on Type I error rate control for large agnostic gene set scans has not been fully explored. Herein, we first outline a statistical strategy for aggregative rare-variant analysis using component gene-level linear kernel score test summary statistics as well as derive simple estimators of the effective number of tests for family-wise error rate control. We then conduct extensive simulation studies to characterize the behavior of our approach relative to direct application of kernel and adaptive methods under a variety of conditions. We also apply our method to two case-control studies, respectively, evaluating rare variation in hereditary prostate cancer and schizophrenia. Finally, we provide open-source R code for public use to facilitate easy application of our methods to existing rare-variant analysis results. © 2017 WILEY PERIODICALS, INC.

Validation of a new ELISA method for in vitro potency testing of hepatitis A vaccines.

PubMed

Morgeaux, S; Variot, P; Daas, A; Costanzo, A

2013-01-01

The goal of the project was to standardise a new in vitro method in replacement of the existing standard method for the determination of hepatitis A virus antigen content in hepatitis A vaccines (HAV) marketed in Europe. This became necessary due to issues with the method used previously, requiring the use of commercial test kits. The selected candidate method, not based on commercial kits, had already been used for many years by an Official Medicines Control Laboratory (OMCL) for routine testing and batch release of HAV. After a pre-qualification phase (Phase 1) that showed the suitability of the commercially available critical ELISA reagents for the determination of antigen content in marketed HAV present on the European market, an international collaborative study (Phase 2) was carried out in order to fully validate the method. Eleven laboratories took part in the collaborative study. They performed assays with the candidate standard method and, in parallel, for comparison purposes, with their own in-house validated methods where these were available. The study demonstrated that the new assay provides a more reliable and reproducible method when compared to the existing standard method. A good correlation of the candidate standard method with the in vivo immunogenicity assay in mice was shown previously for both potent and sub-potent (stressed) vaccines. Thus, the new standard method validated during the collaborative study may be implemented readily by manufacturers and OMCLs for routine batch release but also for in-process control or consistency testing. The new method was approved in October 2012 by Group of Experts 15 of the European Pharmacopoeia (Ph. Eur.) as the standard method for in vitro potency testing of HAV. The relevant texts will be revised accordingly. Critical reagents such as coating reagent and detection antibodies have been adopted by the Ph. Eur. Commission and are available from the EDQM as Ph. Eur. Biological Reference Reagents (BRRs).

[Cancer nursing care education programs: the effectiveness of different teaching methods].

PubMed

Cheng, Yun-Ju; Kao, Yu-Hsiu

2012-10-01

In-service education affects the quality of cancer care directly. Using classroom teaching to deliver in-service education is often ineffective due to participants' large workload and shift requirements. This study evaluated the learning effectiveness of different teaching methods in the dimensions of knowledge, attitude, and learning satisfaction. This study used a quasi-experimental study design. Participants were cancer ward nurses working at one medical center in northern Taiwan. Participants were divided into an experimental group and control group. The experimental group took an e-learning course and the control group took a standard classroom course using the same basic course material. Researchers evaluated the learning efficacy of each group using a questionnaire based on the quality of cancer nursing care learning effectiveness scale. All participants answered the questionnaire once before and once after completing the course. (1) Post-test "knowledge" scores for both groups were significantly higher than pre-test scores for both groups. Post-test "attitude" scores were significantly higher for the control group, while the experimental group reported no significant change. (2) after a covariance analysis of the pre-test scores for both groups, the post-test score for the experimental group was significantly lower than the control group in the knowledge dimension. Post-test scores did not differ significantly from pre-test scores for either group in the attitude dimension. (3) Post-test satisfaction scores between the two groups did not differ significantly with regard to teaching methods. The e-learning method, however, was demonstrated as more flexible than the classroom teaching method. Study results demonstrate the importance of employing a variety of teaching methods to instruct clinical nursing staff. We suggest that both classroom teaching and e-learning instruction methods be used to enhance the quality of cancer nursing care education programs. We also encourage that interactivity between student and instructor be incorporated into e-learning course designs to enhance effectiveness.

Nonvolatile, semivolatile, or volatile: redefining volatile for volatile organic compounds.

PubMed

Võ, Uyên-Uyén T; Morris, Michael P

2014-06-01

Although widely used in air quality regulatory frameworks, the term "volatile organic compound" (VOC) is poorly defined. Numerous standardized tests are currently used in regulations to determine VOC content (and thus volatility), but in many cases the tests do not agree with each other, nor do they always accurately represent actual evaporation rates under ambient conditions. The parameters (time, temperature, reference material, column polarity, etc.) used in the definitions and the associated test methods were created without a significant evaluation of volatilization characteristics in real world settings. Not only do these differences lead to varying VOC content results, but occasionally they conflict with one another. An ambient evaporation study of selected compounds and a few formulated products was conducted and the results were compared to several current VOC test methodologies: SCAQMD Method 313 (M313), ASTM Standard Test Method E 1868-10 (E1868), and US. EPA Reference Method 24 (M24). The ambient evaporation study showed a definite distinction between nonvolatile, semivolatile, and volatile compounds. Some low vapor pressure (LVP) solvents, currently considered exempt as VOCs by some methods, volatilize at ambient conditions nearly as rapidly as the traditional high-volatility solvents they are meant to replace. Conversely, bio-based and heavy hydrocarbons did not readily volatilize, though they often are calculated as VOCs in some traditional test methods. The study suggests that regulatory standards should be reevaluated to more accurately reflect real-world emission from the use of VOC containing products. The definition of VOC in current test methods may lead to regulations that exclude otherwise viable alternatives or allow substitutions of chemicals that may limit the environmental benefits sought in the regulation. A study was conducted to examine volatility of several compounds and a few formulated products under several current VOC test methodologies and ambient evaporation. This paper provides ample evidence to warrant a reevaluation of regulatory standards and provides a framework for progressive developments based on reasonable and scientifically justifiable definitions of VOCs.

The Effect of Using Discourse Analysis Method on Improving Cognitive and Affective Skills in Language and Literature Teaching

ERIC Educational Resources Information Center

Kapanadze, Dilek Ünveren

2018-01-01

The aim of this study is to identify the effect of using discourse analysis method on the skills of reading comprehension, textual analysis, creating discourse and use of language. In this study, the authentic test model with pre-test and post-test control group was used in order to determine the difference of academic achievement between…

Evaluation of the White Test for the Intraoperative Detection of Bile Leakage

PubMed Central

Leelawat, Kawin; Chaiyabutr, Kittipong; Subwongcharoen, Somboon; Treepongkaruna, Sa-ad

2012-01-01

We assess whether the White test is better than the conventional bile leakage test for the intraoperative detection of bile leakage in hepatectomized patients. This study included 30 patients who received elective liver resection. Both the conventional bile leakage test (injecting an isotonic sodium chloride solution through the cystic duct) and the White test (injecting a fat emulsion solution through the cystic duct) were carried out in the same patients. The detection of bile leakage was compared between the conventional method and the White test. A bile leak was demonstrated in 8 patients (26.7%) by the conventional method and in 19 patients (63.3%) by the White test. In addition, the White test detected a significantly higher number of bile leakage sites compared with the conventional method (Wilcoxon signed-rank test; P < 0.001). The White test is better than the conventional test for the intraoperative detection of bile leakage. Based on our study, we recommend that surgeons investigating bile leakage sites during liver resections should use the White test instead of the conventional bile leakage test. PMID:22547901

Evaluation of the white test for the intraoperative detection of bile leakage.

PubMed

Leelawat, Kawin; Chaiyabutr, Kittipong; Subwongcharoen, Somboon; Treepongkaruna, Sa-Ad

2012-01-01

We assess whether the White test is better than the conventional bile leakage test for the intraoperative detection of bile leakage in hepatectomized patients. This study included 30 patients who received elective liver resection. Both the conventional bile leakage test (injecting an isotonic sodium chloride solution through the cystic duct) and the White test (injecting a fat emulsion solution through the cystic duct) were carried out in the same patients. The detection of bile leakage was compared between the conventional method and the White test. A bile leak was demonstrated in 8 patients (26.7%) by the conventional method and in 19 patients (63.3%) by the White test. In addition, the White test detected a significantly higher number of bile leakage sites compared with the conventional method (Wilcoxon signed-rank test; P < 0.001). The White test is better than the conventional test for the intraoperative detection of bile leakage. Based on our study, we recommend that surgeons investigating bile leakage sites during liver resections should use the White test instead of the conventional bile leakage test.

Descriptive and inferential statistical methods used in burns research.

PubMed

Al-Benna, Sammy; Al-Ajam, Yazan; Way, Benjamin; Steinstraesser, Lars

2010-05-01

Burns research articles utilise a variety of descriptive and inferential methods to present and analyse data. The aim of this study was to determine the descriptive methods (e.g. mean, median, SD, range, etc.) and survey the use of inferential methods (statistical tests) used in articles in the journal Burns. This study defined its population as all original articles published in the journal Burns in 2007. Letters to the editor, brief reports, reviews, and case reports were excluded. Study characteristics, use of descriptive statistics and the number and types of statistical methods employed were evaluated. Of the 51 articles analysed, 11(22%) were randomised controlled trials, 18(35%) were cohort studies, 11(22%) were case control studies and 11(22%) were case series. The study design and objectives were defined in all articles. All articles made use of continuous and descriptive data. Inferential statistics were used in 49(96%) articles. Data dispersion was calculated by standard deviation in 30(59%). Standard error of the mean was quoted in 19(37%). The statistical software product was named in 33(65%). Of the 49 articles that used inferential statistics, the tests were named in 47(96%). The 6 most common tests used (Student's t-test (53%), analysis of variance/co-variance (33%), chi(2) test (27%), Wilcoxon & Mann-Whitney tests (22%), Fisher's exact test (12%)) accounted for the majority (72%) of statistical methods employed. A specified significance level was named in 43(88%) and the exact significance levels were reported in 28(57%). Descriptive analysis and basic statistical techniques account for most of the statistical tests reported. This information should prove useful in deciding which tests should be emphasised in educating burn care professionals. These results highlight the need for burn care professionals to have a sound understanding of basic statistics, which is crucial in interpreting and reporting data. Advice should be sought from professionals in the fields of biostatistics and epidemiology when using more advanced statistical techniques. Copyright 2009 Elsevier Ltd and ISBI. All rights reserved.

Correlating the EMC analysis and testing methods for space systems in MIL-STD-1541A

NASA Technical Reports Server (NTRS)

Perez, Reinaldo J.

1990-01-01

A study was conducted to improve the correlation between the electromagnetic compatibility (EMC) analysis models stated in MIL-STD-1541A and the suggested testing methods used for space systems. The test and analysis methods outlined in MIL-STD-1541A are described, and a comparative assessment of testing and analysis techniques as they relate to several EMC areas is presented. Suggestions on present analysis and test methods are introduced to harmonize and bring the analysis and testing tools in MIL-STD-1541A into closer agreement. It is suggested that test procedures in MIL-STD-1541A must be improved by providing alternatives to the present use of shielded enclosures as the primary site for such tests. In addition, the alternate use of anechoic chambers and open field test sites must be considered.

Microbiologic tests in epidemiologic studies: are they reproducible?

PubMed

Aass, A M; Preus, H R; Zambon, J J; Gjermo, P

1994-12-01

Microbiologic assessments are often included in longitudinal studies to elucidate the significance of the association of certain Gram-negative bacteria and the development of periodontal diseases. In such studies, the reliability of methods is crucial. There are several methods to identify putative pathogens, and some of them are commercially available. The purpose of the present study was to compare the reproducibility of four different methods for detecting Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia in order to evaluate their usefulness in epidemiologic studies. The test panel consisted of 10 young subjects and 10 adult periodontitis patients. Subgingival plaque was sampled from sites showing bone loss and "healthy" control sites. The four different methods for detecting the target bacteria were 1) cultivation, 2) Evalusite (a chair-side kit based on ELISA), 3) OmniGene, Inc, based on DNA probes, and 4) indirect immunofluorescence (IIF). The test procedure was repeated after a 1-wk interval and was performed by one examiner. Sites reported to be positive for a microorganism by any of the four methods at one or both examinations were considered to be positive for that organism and included in the analysis. The reproducibility of the four methods was low. The IIF and the cultivation methods showed somewhat higher reproducibility than did the commercial systems. A second test was done for Evalusite, three paper points for sampling being used instead of one as described in the manual. The reproducibility of the second test was improved, indicating that the detection level of the system may influence the reliability.

A Study of the Application of the Lognormal and Gamma Distributions to Corrective Maintenance Repair Time Data.

DTIC Science & Technology

1982-10-01

K-S A R A j 1 10 23 R 3 8 11 16 18 For the lognormal methods the test methods sometimes give different results. The K-S test and the chi-square...significant difference among the three test methods . A previous study has been done using 24 data sets of electronic systems and equipments, using only the W...are suitable descriptors for corrective maintenance repair times, and to estimate the difference caused in assuming an exponential distribution for

Testing for genetic association taking into account phenotypic information of relatives.

PubMed

Uh, Hae-Won; Wijk, Henk Jan van der; Houwing-Duistermaat, Jeanine J

2009-12-15

We investigated efficient case-control association analysis using family data. The outcome of interest was coronary heart disease. We employed existing and new methods that take into account the correlations among related individuals to obtain the proper type I error rates. The methods considered for autosomal single-nucleotide polymorphisms were: 1) generalized estimating equations-based methods, 2) variance-modified Cochran-Armitage (MCA) trend test incorporating kinship coefficients, and 3) genotypic modified quasi-likelihood score test. Additionally, for X-linked single-nucleotide polymorphisms we proposed a two-degrees-of-freedom test. Performance of these methods was tested using Framingham Heart Study 500 k array data.

Toxicity and bioaccumulation of sediment-associated contaminants using freshwater invertebrates: A review of methods and applications

USGS Publications Warehouse

Ingersoll, C.G.; Ankley, G.T.; Benoit, D.A.; Brunson, E.L.; Burton, G.A.; Dwyer, F.J.; Hoke, R.A.; Landrum, P.F.; Norberg-King, T. J.; Winger, P.V.

1995-01-01

This paper reviews recent developments in methods for evaluating the toxicity and bioaccumulation of contaminants associated with freshwater sediments and summarizes example case studies demonstrating the application of these methods. Over the past decade, research has emphasized development of more specific testing procedures for conducting 10-d toxicity tests with the amphipod Hyalella azteca and the midge Chironomus tentans. Toxicity endpoints measured in these tests are survival for H. azteca and survival and growth for C. tentans. Guidance has also been developed for conducting 28-d bioaccumulation tests with the oligochaete Lumbriculus variegatus, including determination of bioaccumulation kinetics for different compound classes. These methods have been applied to a variety of sediments to address issues ranging from site assessments to bioavailability of organic and inorganic contaminants using field-collected and laboratory-spiked samples. Survival and growth of controls routinely meet or exceed test acceptability criteria. Results of laboratory bioaccumulation studies with L. variegatus have been confirmed with comparisons to residues (PCBs, PAHs, DDT) present from synoptically collected field populations of oligochaetes. Additional method development is currently underway to develop chronic toxicity tests and to provide additional data-confirming responses observed in laboratory sediment tests with natural benthic populations.

Estimating a test's accuracy using tailored meta-analysis-How setting-specific data may aid study selection.

PubMed

Willis, Brian H; Hyde, Christopher J

2014-05-01

To determine a plausible estimate for a test's performance in a specific setting using a new method for selecting studies. It is shown how routine data from practice may be used to define an "applicable region" for studies in receiver operating characteristic space. After qualitative appraisal, studies are selected based on the probability that their study accuracy estimates arose from parameters lying in this applicable region. Three methods for calculating these probabilities are developed and used to tailor the selection of studies for meta-analysis. The Pap test applied to the UK National Health Service (NHS) Cervical Screening Programme provides a case example. The meta-analysis for the Pap test included 68 studies, but at most 17 studies were considered applicable to the NHS. For conventional meta-analysis, the sensitivity and specificity (with 95% confidence intervals) were estimated to be 72.8% (65.8, 78.8) and 75.4% (68.1, 81.5) compared with 50.9% (35.8, 66.0) and 98.0% (95.4, 99.1) from tailored meta-analysis using a binomial method for selection. Thus, for a cervical intraepithelial neoplasia (CIN) 1 prevalence of 2.2%, the post-test probability for CIN 1 would increase from 6.2% to 36.6% between the two methods of meta-analysis. Tailored meta-analysis provides a method for augmenting study selection based on the study's applicability to a setting. As such, the summary estimate is more likely to be plausible for a setting and could improve diagnostic prediction in practice. Copyright © 2014 Elsevier Inc. All rights reserved.

Effectiveness of Jigsaw learning compared to lecture-based learning in dental education.

PubMed

Sagsoz, O; Karatas, O; Turel, V; Yildiz, M; Kaya, E

2017-02-01

The objective of this study was to evaluate the success levels of students using the Jigsaw learning method in dental education. Fifty students with similar grade point average (GPA) scores were selected and randomly assigned into one of two groups (n = 25). A pretest concerning 'adhesion and bonding agents in dentistry' was administered to all students before classes. The Jigsaw learning method was applied to the experimental group for 3 weeks. At the same time, the control group was taking classes using the lecture-based learning method. At the end of the 3 weeks, all students were retested (post-test) on the subject. A retention test was administered 3 weeks after the post-test. Mean scores were calculated for each test for the experimental and control groups, and the data obtained were analysed using the independent samples t-test. No significant difference was determined between the Jigsaw and lecture-based methods at pretest or post-test. The highest mean test score was observed in the post-test with the Jigsaw method. In the retention test, success with the Jigsaw method was significantly higher than that with the lecture-based method. The Jigsaw method is as effective as the lecture-based method. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Using a fuzzy comprehensive evaluation method to determine product usability: A test case.

PubMed

Zhou, Ronggang; Chan, Alan H S

2017-01-01

In order to take into account the inherent uncertainties during product usability evaluation, Zhou and Chan [1] proposed a comprehensive method of usability evaluation for products by combining the analytic hierarchy process (AHP) and fuzzy evaluation methods for synthesizing performance data and subjective response data. This method was designed to provide an integrated framework combining the inevitable vague judgments from the multiple stages of the product evaluation process. In order to illustrate the effectiveness of the model, this study used a summative usability test case to assess the application and strength of the general fuzzy usability framework. To test the proposed fuzzy usability evaluation framework [1], a standard summative usability test was conducted to benchmark the overall usability of a specific network management software. Based on the test data, the fuzzy method was applied to incorporate both the usability scores and uncertainties involved in the multiple components of the evaluation. Then, with Monte Carlo simulation procedures, confidence intervals were used to compare the reliabilities among the fuzzy approach and two typical conventional methods combining metrics based on percentages. This case study showed that the fuzzy evaluation technique can be applied successfully for combining summative usability testing data to achieve an overall usability quality for the network software evaluated. Greater differences of confidence interval widths between the method of averaging equally percentage and weighted evaluation method, including the method of weighted percentage averages, verified the strength of the fuzzy method.

Validation of an Instrument to Measure High School Students' Attitudes toward Fitness Testing

ERIC Educational Resources Information Center

Mercier, Kevin; Silverman, Stephen

2014-01-01

Purpose: The purpose of this investigation was to develop an instrument that has scores that are valid and reliable for measuring students' attitudes toward fitness testing. Method: The method involved the following steps: (a) an elicitation study, (b) item development, (c) a pilot study, and (d) a validation study. The pilot study included 427…

Development of a diagnostic test set to assess agreement in breast pathology: practical application of the Guidelines for Reporting Reliability and Agreement Studies (GRRAS).

PubMed

Oster, Natalia V; Carney, Patricia A; Allison, Kimberly H; Weaver, Donald L; Reisch, Lisa M; Longton, Gary; Onega, Tracy; Pepe, Margaret; Geller, Berta M; Nelson, Heidi D; Ross, Tyler R; Tosteson, Aanna N A; Elmore, Joann G

2013-02-05

Diagnostic test sets are a valuable research tool that contributes importantly to the validity and reliability of studies that assess agreement in breast pathology. In order to fully understand the strengths and weaknesses of any agreement and reliability study, however, the methods should be fully reported. In this paper we provide a step-by-step description of the methods used to create four complex test sets for a study of diagnostic agreement among pathologists interpreting breast biopsy specimens. We use the newly developed Guidelines for Reporting Reliability and Agreement Studies (GRRAS) as a basis to report these methods. Breast tissue biopsies were selected from the National Cancer Institute-funded Breast Cancer Surveillance Consortium sites. We used a random sampling stratified according to woman's age (40-49 vs. ≥50), parenchymal breast density (low vs. high) and interpretation of the original pathologist. A 3-member panel of expert breast pathologists first independently interpreted each case using five primary diagnostic categories (non-proliferative changes, proliferative changes without atypia, atypical ductal hyperplasia, ductal carcinoma in situ, and invasive carcinoma). When the experts did not unanimously agree on a case diagnosis a modified Delphi method was used to determine the reference standard consensus diagnosis. The final test cases were stratified and randomly assigned into one of four unique test sets. We found GRRAS recommendations to be very useful in reporting diagnostic test set development and recommend inclusion of two additional criteria: 1) characterizing the study population and 2) describing the methods for reference diagnosis, when applicable.

Correlation between microdilution, Etest, and disk diffusion methods for antifungal susceptibility testing of fluconazole against Candida sp. blood isolates.

PubMed

Menezes, Everardo Albuquerque; Vasconcelos Júnior, Antônio Alexandre de; Ângelo, Maria Rozzelê Ferreira; Cunha, Maria da Conceição dos Santos Oliveira; Cunha, Francisco Afrânio

2013-01-01

Antifungal susceptibility testing assists in finding the appropriate treatment for fungal infections, which are increasingly common. However, such testing is not very widespread. There are several existing methods, and the correlation between such methods was evaluated in this study. The susceptibility to fluconazole of 35 strains of Candida sp. isolated from blood cultures was evaluated by the following methods: microdilution, Etest, and disk diffusion. The correlation between the methods was around 90%. The disk diffusion test exhibited a good correlation and can be used in laboratory routines to detect strains of Candida sp. that are resistant to fluconazole.

A Computationally Efficient Hypothesis Testing Method for Epistasis Analysis using Multifactor Dimensionality Reduction

PubMed Central

Pattin, Kristine A.; White, Bill C.; Barney, Nate; Gui, Jiang; Nelson, Heather H.; Kelsey, Karl R.; Andrew, Angeline S.; Karagas, Margaret R.; Moore, Jason H.

2008-01-01

Multifactor dimensionality reduction (MDR) was developed as a nonparametric and model-free data mining method for detecting, characterizing, and interpreting epistasis in the absence of significant main effects in genetic and epidemiologic studies of complex traits such as disease susceptibility. The goal of MDR is to change the representation of the data using a constructive induction algorithm to make nonadditive interactions easier to detect using any classification method such as naïve Bayes or logistic regression. Traditionally, MDR constructed variables have been evaluated with a naïve Bayes classifier that is combined with 10-fold cross validation to obtain an estimate of predictive accuracy or generalizability of epistasis models. Traditionally, we have used permutation testing to statistically evaluate the significance of models obtained through MDR. The advantage of permutation testing is that it controls for false-positives due to multiple testing. The disadvantage is that permutation testing is computationally expensive. This is in an important issue that arises in the context of detecting epistasis on a genome-wide scale. The goal of the present study was to develop and evaluate several alternatives to large-scale permutation testing for assessing the statistical significance of MDR models. Using data simulated from 70 different epistasis models, we compared the power and type I error rate of MDR using a 1000-fold permutation test with hypothesis testing using an extreme value distribution (EVD). We find that this new hypothesis testing method provides a reasonable alternative to the computationally expensive 1000-fold permutation test and is 50 times faster. We then demonstrate this new method by applying it to a genetic epidemiology study of bladder cancer susceptibility that was previously analyzed using MDR and assessed using a 1000-fold permutation test. PMID:18671250

[Serological diagnosis of whooping cough using immunoblot methods].

PubMed

Lochman, I; Pokorná, L; Mertová, H

2017-01-01

The aim of this study was to challenge the conclusion presented in the current recommendations of the EU Perstrain Group (European group of reference laboratories) [17] that immunoblotting methods are not appropriate serological methods for the diagnosis of pertussis because their results cannot be quantified. To consider benefits of these methods for the diagnosis of Bordetella infections was another aim of this work. The residual sera from routine testing intended for disposal and results of routine tests for Bordetella infections performed in Spadia Lab in 2015 and 2016 were used in this study. The test samples were anonymized. Standard commercial ELISA and immunoblot kits were used for analyses. Using the TestLine Clinical Diagnostics Company kits, we have shown that, contrary to the conclusion of the EU Perstrain Group, quantification of the immunoblot results is possible and that these methods can improve the diagnosis of Bordetella infections, ultimately making it more effective.

Study of the location of testing area in residual stress measurement by Moiré interferometry combined with hole-drilling method

NASA Astrophysics Data System (ADS)

Qin, Le; Xie, HuiMin; Zhu, RongHua; Wu, Dan; Che, ZhiGang; Zou, ShiKun

2014-04-01

This paper investigates the effect of the location of testing area in residual stress measurement by Moiré interferometry combined with hole-drilling method. The selection of the location of the testing area is analyzed from theory and experiment. In the theoretical study, the factors which affect the surface released radial strain ɛ r were analyzed on the basis of the formulae of the hole-drilling method, and the relations between those factors and ɛ r were established. By combining Moiré interferometry with the hole-drilling method, the residual stress of interference-fit specimen was measured to verify the theoretical analysis. According to the analysis results, the testing area for minimizing the error of strain measurement is determined. Moreover, if the orientation of the maximum principal stress is known, the value of strain will be measured with higher precision by the Moiré interferometry method.

How to test validity in orthodontic research: a mixed dentition analysis example.

PubMed

Donatelli, Richard E; Lee, Shin-Jae

2015-02-01

The data used to test the validity of a prediction method should be different from the data used to generate the prediction model. In this study, we explored whether an independent data set is mandatory for testing the validity of a new prediction method and how validity can be tested without independent new data. Several validation methods were compared in an example using the data from a mixed dentition analysis with a regression model. The validation errors of real mixed dentition analysis data and simulation data were analyzed for increasingly large data sets. The validation results of both the real and the simulation studies demonstrated that the leave-1-out cross-validation method had the smallest errors. The largest errors occurred in the traditional simple validation method. The differences between the validation methods diminished as the sample size increased. The leave-1-out cross-validation method seems to be an optimal validation method for improving the prediction accuracy in a data set with limited sample sizes. Copyright © 2015 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

A new method to address verification bias in studies of clinical screening tests: cervical cancer screening assays as an example.

PubMed

Xue, Xiaonan; Kim, Mimi Y; Castle, Philip E; Strickler, Howard D

2014-03-01

Studies to evaluate clinical screening tests often face the problem that the "gold standard" diagnostic approach is costly and/or invasive. It is therefore common to verify only a subset of negative screening tests using the gold standard method. However, undersampling the screen negatives can lead to substantial overestimation of the sensitivity and underestimation of the specificity of the diagnostic test. Our objective was to develop a simple and accurate statistical method to address this "verification bias." We developed a weighted generalized estimating equation approach to estimate, in a single model, the accuracy (eg, sensitivity/specificity) of multiple assays and simultaneously compare results between assays while addressing verification bias. This approach can be implemented using standard statistical software. Simulations were conducted to assess the proposed method. An example is provided using a cervical cancer screening trial that compared the accuracy of human papillomavirus and Pap tests, with histologic data as the gold standard. The proposed approach performed well in estimating and comparing the accuracy of multiple assays in the presence of verification bias. The proposed approach is an easy to apply and accurate method for addressing verification bias in studies of multiple screening methods. Copyright © 2014 Elsevier Inc. All rights reserved.

Identifying Dyslexia in Adults: An Iterative Method Using the Predictive Value of Item Scores and Self-Report Questions

ERIC Educational Resources Information Center

Tamboer, Peter; Vorst, Harrie C. M.; Oort, Frans J.

2014-01-01

Methods for identifying dyslexia in adults vary widely between studies. Researchers have to decide how many tests to use, which tests are considered to be the most reliable, and how to determine cut-off scores. The aim of this study was to develop an objective and powerful method for diagnosing dyslexia. We took various methodological measures,…

A Comparison of the Approaches of Generalizability Theory and Item Response Theory in Estimating the Reliability of Test Scores for Testlet-Composed Tests

ERIC Educational Resources Information Center

Lee, Guemin; Park, In-Yong

2012-01-01

Previous assessments of the reliability of test scores for testlet-composed tests have indicated that item-based estimation methods overestimate reliability. This study was designed to address issues related to the extent to which item-based estimation methods overestimate the reliability of test scores composed of testlets and to compare several…

DuPont qualicon BAX system real-time PCR assay for Escherichia coli O157:H7.

PubMed

Burns, Frank; Fleck, Lois; Andaloro, Bridget; Davis, Eugene; Rohrbeck, Jeff; Tice, George; Wallace, Morgan

2011-01-01

Evaluations were conducted to test the performance of the BAX System Real-Time PCR assay, which was certified as Performance Tested Method 031002 for screening E. coli O157:H7 in ground beef, beef trim, spinach, and lettuce. Method comparison studies performed on samples with low-level inoculates showed that the BAX System demonstrates a sensitivity equivalent or superior to the FDA-BAM and the USDA-FSIS culture methods, but with a significantly shorter time to result. Tests to evaluate inclusivity and exclusivity returned no false-negative and no false-positive results on a diverse panel of isolates, and tests for lot-to-lot variability and tablet stability demonstrated consistent performance. Ruggedness studies determined that none of the factors examined affect the performance of the assay. An accelerated shelf life study determined an initial 36 month shelf life for the test kit.

An extended sequential goodness-of-fit multiple testing method for discrete data.

PubMed

Castro-Conde, Irene; Döhler, Sebastian; de Uña-Álvarez, Jacobo

2017-10-01

The sequential goodness-of-fit (SGoF) multiple testing method has recently been proposed as an alternative to the familywise error rate- and the false discovery rate-controlling procedures in high-dimensional problems. For discrete data, the SGoF method may be very conservative. In this paper, we introduce an alternative SGoF-type procedure that takes into account the discreteness of the test statistics. Like the original SGoF, our new method provides weak control of the false discovery rate/familywise error rate but attains false discovery rate levels closer to the desired nominal level, and thus it is more powerful. We study the performance of this method in a simulation study and illustrate its application to a real pharmacovigilance data set.

A comparative study of the effectiveness of "Star Show" vs. "Participatory Oriented Planetarium" lessons in a middle school Starlab setting

NASA Astrophysics Data System (ADS)

Platco, Nicholas L.., Jr.

2005-06-01

The purpose of this study was to compare the effectiveness of "Star Show" and the "Participatory Oriented Planetarium" (POP) instructional programs in a middle school Starlab setting. The Star Show is a planetarium program that relies heavily on an audiovisual/lecture format to impart information, while the POP method of instruction is an inquiry, activity-based approach to teaching astronomy. All Star Show and POP lessons were conducted in a Starlab planetarium. This study examined the effectiveness of the two methods on the attainment of astronomy knowledge, changes in student attitudes toward astronomy, retention of knowledge, and gender differences. A pilot study (N = 69) was conducted at a middle school near King of Prussia, Pennsylvania. The main study (N = 295) was conducted at a middle school near Reading, Pennsylvania. All students were pretested and posttested in both studies. The testing instruments included a 60-question paper-and-pencil content test and a 22-item Likert-style science attitude test. The content test was judged to be valid and reliable by a panel of science educators. The attitude test is a field-tested attitude survey developed by Michael Zeilik. The topics included in the Star Show and POP lessons were seasons, moon phases, eclipses, stars, and constellations. The Star Show programs used in this study are professionally prepared planetarium programs from Jeff Bowen Productions. Several planetarium educators who have been involved with planetarium training workshops throughout the United States developed the POP lessons used in this study. The Star Show was clearly the more effective method for improving student knowledge in both the pilot and main studies. Both methods were equally effective for improving student attitudes toward astronomy. The POP method was the more effective method of instruction when retention of knowledge was examined four weeks after the treatments ended. Gender did not have any significant effect on this study. In light of the results of this study, it appears that both Star Show and POP methods of instruction should continue to play important roles in planetarium education. A combination of the two methods is clearly the ideal solution when teaching astronomy to middle school students in a Starlab setting.

Resampling and Distribution of the Product Methods for Testing Indirect Effects in Complex Models

ERIC Educational Resources Information Center

Williams, Jason; MacKinnon, David P.

2008-01-01

Recent advances in testing mediation have found that certain resampling methods and tests based on the mathematical distribution of 2 normal random variables substantially outperform the traditional "z" test. However, these studies have primarily focused only on models with a single mediator and 2 component paths. To address this limitation, a…

A Primer-Test Centered Equating Method for Setting Cut-Off Scores

ERIC Educational Resources Information Center

Zhu, Weimo; Plowman, Sharon Ann; Park, Youngsik

2010-01-01

This study evaluated the use of a new primary field test method based on test equating to address inconsistent classification among field tests. We analyzed students' information on the Progressive Aerobic Cardiovascular Endurance Run (PACER), mile run (MR), and VO[subscript 2]max from three data sets (college: n = 94; middle school: n = 39;…

Using an interlaboratory study to revise methods for conducting 10-d to 42-d water or sediment toxicity tests with Hyalella azteca

USGS Publications Warehouse

Ivey, Chris D.; Ingersoll, Christopher G.; Brumbaugh, William G.; Hammer, Edward J.; Mount, David R.; Hockett, J. Russell; Norberg-King, Teresa J.; Soucek, Dave; Taylor, Lisa

2016-01-01

Studies have been conducted to refine US Environmental Protection Agency, ASTM International, and Environment Canada standard methods for conducting 42-d reproduction tests with Hyalella azteca in water or in sediment. Modifications to the H. azteca method include better-defined ionic composition requirements for exposure water (i.e., >15 mg/L of chloride and >0.02 mg/L of bromide) and improved survival, growth, and reproduction with alternate diets provided as increased rations over time in water-only or whole-sediment toxicity tests. A total of 24 laboratories volunteered to participate in the present interlaboratory study evaluating the performance of H. azteca in 42-d studies in control sand or control sediment using the refined methods. Improved growth and reproduction of H. azteca was observed with 2 alternate diets of 1) ramped diatoms (Thalassiosira weissflogii) + ramped Tetramin or 2) yeast–cerophyll–trout chow (YCT) + ramped Tetramin, especially when compared with results from the traditional diet of 1.8 mg YCT/d. Laboratories were able to meet proposed test acceptability criteria and in most cases had lower variation in growth or reproduction compared with previous interlaboratory studies using the traditional YCT diet. Laboratory success in conducting 42-d H. azteca exposures benefited from adherence to several key requirements of the detailed testing, culturing, and handling methods. Results from the present interlaboratory study are being used to help revise standard methods for conducting 10-d to 42-d water or sediment toxicity exposures with H. azteca.

Further development of LLNA:DAE method as stand-alone skin-sensitization testing method and applied for evaluation of relative skin-sensitizing potency between chemicals.

PubMed

Yamashita, Kunihiko; Shinoda, Shinsuke; Hagiwara, Saori; Itagaki, Hiroshi

2015-04-01

To date, there has been no well-established local lymph node assay (LLNA) that includes an elicitation phase. Therefore, we developed a modified local lymph node assay with an elicitation phase (LLNA:DAE) to discriminate true skin sensitizers from chemicals that gave borderline positive results and previously reported this assay. To develop the LLNA:DAE method as a useful stand-alone testing method, we investigated the complete procedure for the LLNA:DAE method using hexyl cinnamic aldehyde (HCA), isoeugenol, and 2,4-dinitrochlorobenzene (DNCB) as test compounds. We defined the LLNA:DAE procedure as follows: in the dose-finding test, four concentrations of chemical applied to dorsum of the right ear on days 1, 2, and 3 and dorsum of both ears on day 10. Ear thickness and skin irritation score were measured on days 1, 3, 5, 10, and 12. Local lymph nodes were excised and weighed on day 12. The test dose for the primary LLNA:DAE study was selected as the dose that gave the highest left ear lymph node weight in the dose-finding study, or the lowest dose that produced a left ear lymph node of over 4 mg. This procedure was validated using nine different chemicals. Furthermore, qualitative relationship was observed between the degree of elicitation response in the left ear lymph node and the skin sensitizing potency of 32 chemicals tested in this study and the previous study. These results indicated that LLNA:DAE method was as first LLNA method that was able to evaluate the skin sensitizing potential and potency in elicitation response.

Comparison of Parametric and Nonparametric Bootstrap Methods for Estimating Random Error in Equipercentile Equating

ERIC Educational Resources Information Center

Cui, Zhongmin; Kolen, Michael J.

2008-01-01

This article considers two methods of estimating standard errors of equipercentile equating: the parametric bootstrap method and the nonparametric bootstrap method. Using a simulation study, these two methods are compared under three sample sizes (300, 1,000, and 3,000), for two test content areas (the Iowa Tests of Basic Skills Maps and Diagrams…

Adjusting for partial verification or workup bias in meta-analyses of diagnostic accuracy studies.

PubMed

de Groot, Joris A H; Dendukuri, Nandini; Janssen, Kristel J M; Reitsma, Johannes B; Brophy, James; Joseph, Lawrence; Bossuyt, Patrick M M; Moons, Karel G M

2012-04-15

A key requirement in the design of diagnostic accuracy studies is that all study participants receive both the test under evaluation and the reference standard test. For a variety of practical and ethical reasons, sometimes only a proportion of patients receive the reference standard, which can bias the accuracy estimates. Numerous methods have been described for correcting this partial verification bias or workup bias in individual studies. In this article, the authors describe a Bayesian method for obtaining adjusted results from a diagnostic meta-analysis when partial verification or workup bias is present in a subset of the primary studies. The method corrects for verification bias without having to exclude primary studies with verification bias, thus preserving the main advantages of a meta-analysis: increased precision and better generalizability. The results of this method are compared with the existing methods for dealing with verification bias in diagnostic meta-analyses. For illustration, the authors use empirical data from a systematic review of studies of the accuracy of the immunohistochemistry test for diagnosis of human epidermal growth factor receptor 2 status in breast cancer patients.

Two-probe versus van der Pauw method in studying the piezoresistivity of single-wall carbon nanotube thin films

NASA Astrophysics Data System (ADS)

Yao, Yanbo; Duan, Xiaoshuang; Luo, Jiangjiang; Liu, Tao

2017-11-01

The use of the van der Pauw (VDP) method for characterizing and evaluating the piezoresistive behavior of carbon nanomaterial enabled piezoresistive sensors have not been systematically studied. By using single-wall carbon nanotube (SWCNT) thin films as a model system, herein we report a coupled electrical-mechanical experimental study in conjunction with a multiphysics finite element simulation as well as an analytic analysis to compare the two-probe and VDP testing configuration in evaluating the piezoresistive behavior of carbon nanomaterial enabled piezoresistive sensors. The key features regarding the sample aspect ratio dependent piezoresistive sensitivity or gauge factor were identified for the VDP testing configuration. It was found that the VDP test configuration offers consistently higher piezoresistive sensitivity than the two-probe testing method.

The Impact of Test Dimensionality, Common-Item Set Format, and Scale Linking Methods on Mixed-Format Test Equating

ERIC Educational Resources Information Center

Öztürk-Gübes, Nese; Kelecioglu, Hülya

2016-01-01

The purpose of this study was to examine the impact of dimensionality, common-item set format, and different scale linking methods on preserving equity property with mixed-format test equating. Item response theory (IRT) true-score equating (TSE) and IRT observed-score equating (OSE) methods were used under common-item nonequivalent groups design.…

The importance of aerodynamics for prosthetic limb design used by competitive cyclists with an amputation: An introduction.

PubMed

Dyer, Bryce

2015-06-01

This study introduces the importance of the aerodynamics to prosthetic limb design for athletes with either a lower-limb or upper-limb amputation. The study comprises two elements: 1) An initial experiment investigating the stability of outdoor velodrome-based field tests, and 2) An experiment evaluating the application of outdoor velodrome aerodynamic field tests to detect small-scale changes in aerodynamic drag respective of prosthetic limb componentry changes. An outdoor field-testing method is used to detect small and repeatable changes in the aerodynamic drag of an able-bodied cyclist. These changes were made at levels typical of alterations in prosthetic componentry. The field-based test method of assessment is used at a smaller level of resolution than previously reported. With a carefully applied protocol, the field test method proved to be statistically stable. The results of the field test experiments demonstrate a noticeable change in overall athlete performance. Aerodynamic refinement of artificial limbs is worthwhile for athletes looking to maximise their competitive performance. A field-testing method illustrates the importance of the aerodynamic optimisation of prosthetic limb components. The field-testing protocol undertaken in this study gives an accessible and affordable means of doing so by prosthetists and sports engineers. Using simple and accessible field-testing methods, this exploratory experiment demonstrates how small changes to riders' equipment, consummate of the scale of a small change in prosthetics componentry, can affect the performance of an athlete. Prosthetists should consider such opportunities for performance enhancement when possible. © The International Society for Prosthetics and Orthotics 2014.

Principles and Applications of Ultrasonic-Based Nondestructive Methods for Self-Healing in Cementitious Materials

PubMed Central

Ahn, Eunjong; Kim, Hyunjun; Sim, Sung-Han; Shin, Sung Woo; Shin, Myoungsu

2017-01-01

Recently, self-healing technologies have emerged as a promising approach to extend the service life of social infrastructure in the field of concrete construction. However, current evaluations of the self-healing technologies developed for cementitious materials are mostly limited to lab-scale experiments to inspect changes in surface crack width (by optical microscopy) and permeability. Furthermore, there is a universal lack of unified test methods to assess the effectiveness of self-healing technologies. Particularly, with respect to the self-healing of concrete applied in actual construction, nondestructive test methods are required to avoid interrupting the use of the structures under evaluation. This paper presents a review of all existing research on the principles of ultrasonic test methods and case studies pertaining to self-healing concrete. The main objective of the study is to examine the applicability and limitation of various ultrasonic test methods in assessing the self-healing performance. Finally, future directions on the development of reliable assessment methods for self-healing cementitious materials are suggested. PMID:28772640

Cosmetics Europe multi-laboratory pre-validation of the SkinEthic™ reconstituted human corneal epithelium test method for the prediction of eye irritation.

PubMed

Alépée, N; Bessou-Touya, S; Cotovio, J; de Smedt, A; de Wever, B; Faller, C; Jones, P; Le Varlet, B; Marrec-Fairley, M; Pfannenbecker, U; Tailhardat, M; van Goethem, F; McNamee, P

2013-08-01

Cosmetics Europe, The Personal Care Association, known as Colipa before 2012, conducted a program of technology transfer and assessment of Within/Between Laboratory (WLV/BLV) reproducibility of the SkinEthic™ Reconstituted Human Corneal Epithelium (HCE) as one of two human reconstructed tissue eye irritation test methods. The SkinEthic™ HCE test method involves two exposure time treatment procedures - one for short time exposure (10 min - SE) and the other for long time exposure (60 min - LE) of tissues to test substance. This paper describes pre-validation studies of the SkinEthic™ HCE test method (SE and LE protocols) as well as the Eye Peptide Reactivity Assay (EPRA). In the SE WLV study, 30 substances were evaluated. A consistent outcome with respect to viability measurement across all runs was observed with all substances showing an SD of less than 18%. In the LE WLV study, 44 out of 45 substances were consistently classified. These data demonstrated a high level of reproducibility within laboratory for both the SE and LE treatment procedures. For the LE BLV, 19 out of 20 substances were consistently classified between the three laboratories, again demonstrating a high level of reproducibility between laboratories. The results for EPRA WLV and BLV studies demonstrated that all substances analysed were categorised similarly and that the method is reproducible. The SkinEthic™ HCE test method entered into the experimental phase of a formal ECVAM validation program in 2010. Copyright © 2013. Published by Elsevier Ltd.

Self-directed learning can outperform direct instruction in the course of a modern German medical curriculum - results of a mixed methods trial.

PubMed

Peine, Arne; Kabino, Klaus; Spreckelsen, Cord

2016-06-03

Modernised medical curricula in Germany (so called "reformed study programs") rely increasingly on alternative self-instructed learning forms such as e-learning and curriculum-guided self-study. However, there is a lack of evidence that these methods can outperform conventional teaching methods such as lectures and seminars. This study was conducted in order to compare extant traditional teaching methods with new instruction forms in terms of learning effect and student satisfaction. In a randomised trial, 244 students of medicine in their third academic year were assigned to one of four study branches representing self-instructed learning forms (e-learning and curriculum-based self-study) and instructed learning forms (lectures and seminars). All groups participated in their respective learning module with standardised materials and instructions. Learning effect was measured with pre-test and post-test multiple-choice questionnaires. Student satisfaction and learning style were examined via self-assessment. Of 244 initial participants, 223 completed the respective module and were included in the study. In the pre-test, the groups showed relatively homogenous scores. All students showed notable improvements compared with the pre-test results. Participants in the non-self-instructed learning groups reached scores of 14.71 (seminar) and 14.37 (lecture), while the groups of self-instructed learners reached higher scores with 17.23 (e-learning) and 15.81 (self-study). All groups improved significantly (p < .001) in the post-test regarding their self-assessment, led by the e-learning group, whose self-assessment improved by 2.36. The study shows that students in modern study curricula learn better through modern self-instructed methods than through conventional methods. These methods should be used more, as they also show good levels of student acceptance and higher scores in personal self-assessment of knowledge.

Software Engineering Laboratory (SEL) Ada performance study report

NASA Technical Reports Server (NTRS)

Booth, Eric W.; Stark, Michael E.

1991-01-01

The goals of the Ada Performance Study are described. The methods used are explained. Guidelines for future Ada development efforts are given. The goals and scope of the study are detailed, and the background of Ada development in the Flight Dynamics Division (FDD) is presented. The organization and overall purpose of each test are discussed. The purpose, methods, and results of each test and analyses of these results are given. Guidelines for future development efforts based on the analysis of results from this study are provided. The approach used on the performance tests is discussed.

Non-destructive vacuum decay method for pre-filled syringe closure integrity testing compared with dye ingress testing and high-voltage leak detection.

PubMed

Simonetti, Andrea; Amari, Filippo

2015-01-01

In reaction to the limitations of the traditional sterility test methods, in 2008, the U.S. Food and Drug Administration issued the guidance "Container and Closure System Integrity Testing in Lieu of Sterility Testing as a Component of the Stability Protocol for Sterile Products" encouraging sterile drug manufacturers to use properly validated physical methods, apart from conventional microbial challenge testing, to confirm container closure integrity as part of the stability protocol. The case study presented in this article investigated the capability of four container closure integrity testing methods to detect simulated defects of different sizes and types on glass syringes, prefilled both with drug product intended for parenteral administration and sterile water. The drug product was a flu vaccine (Agrippal, Novartis Vaccines, Siena, Italy). Vacuum decay, pharmacopoeial dye ingress test, Novartis specific dye ingress test, and high-voltage leak detection were, in succession, the methods involved in the comparative studies. The case study execution was preceded by the preparation of two independent sets of reference prefilled syringes, classified, respectively, as examples of conforming to closure integrity requirements (negative controls) and as defective (positive controls). Positive controls were, in turn, split in six groups, three of with holes laser-drilled through the prefilled syringe glass barrel, while the other three with capillary tubes embedded in the prefilled syringe plunger. These reference populations were then investigated by means of validated equipment used for container closure integrity testing of prefilled syringe commercial production; data were collected and analyzed to determine the detection rate and the percentage of false results. Results showed that the vacuum decay method had the highest performance in terms of detection sensitivity and also ensured the best reliability and repeatability of measurements. An innovative technical solution, preventing possible prefilled syringe plunger movement during container closure integrity testing execution, is presented as well. The growing need to meet sterile drug products' regulatory, quality, and safety expectations has progressively driven new developments and improvements both in container closure integrity testing methods and in the respective equipment, over the last years. Indeed, container closure integrity testing establishes the container closure system capability to provide required protection to the drug product and to demonstrate maintenance of product sterility over its shelf life. This article describes the development of four container closure integrity testing approaches for the evaluation of glass prefilled syringe closure integrity, including two destructive (pharmacopoeial and Novartis specific dye ingress test) and two non-destructive (vacuum decay and high-voltage leak detection) methods. The important finding from the validation of comparative studies was that the vacuum decay method resulted in the most effective, reliable and repeatable detection of defective samples, whether the defect was exposed to sterile water, to drug product, or to air. Complete sets of known defects were created for this purpose (5 μm, 10 μm, 20 μm certified leakages by laser drilled holes and capillary tubes). All investigations and studies were conducted at Bonfiglioli Engineering S.r.l. (Vigarano Pieve, Ferrara, Italy) and at Novartis Vaccines (Sovicille, Siena, Italy). © PDA, Inc. 2015.

Half Wing N219 Aircraft Model Clean Configuration for Flutter Test On Low Speed Wind Tunnel

NASA Astrophysics Data System (ADS)

Syamsuar, Sayuti; Sampurno, Budi; Mayang Mahasti, Katia; Bayu Sakti Pratama, Muchamad; Widi Sasongko, Triyono; Kartika, Nina; Suksmono, Adityo; Aji Saputro, Mohamad Ivan; Bahtera Eskayudha, Dimas

2018-04-01

Flutter is a rapid self-feeding motion which is caused by the interaction of aerodynamic, structural and inertial forces. Flutter can cause major damage on aircraft structure which can lead to fatal accident in aviation. Several methods have been evolved to avoid the flutter phenomena occur during the flight envelope of aircraft design. On this study, method was developed by Indonesian Aerospace which consist of Finite Element Method (FEM) analysis, Ground Vibration Test (GVT), and Wind Tunnel Flutter Test (WTT). Based on the study, FEM have similar results toward to Wind Tunnel Flutter Test conjunction the clean configuration of N219 aircraft half wing model.

Experimental Evaluation of Suitability of Selected Multi-Criteria Decision-Making Methods for Large-Scale Agent-Based Simulations

PubMed Central

2016-01-01

Multi-criteria decision-making (MCDM) can be formally implemented by various methods. This study compares suitability of four selected MCDM methods, namely WPM, TOPSIS, VIKOR, and PROMETHEE, for future applications in agent-based computational economic (ACE) models of larger scale (i.e., over 10 000 agents in one geographical region). These four MCDM methods were selected according to their appropriateness for computational processing in ACE applications. Tests of the selected methods were conducted on four hardware configurations. For each method, 100 tests were performed, which represented one testing iteration. With four testing iterations conducted on each hardware setting and separated testing of all configurations with the–server parameter de/activated, altogether, 12800 data points were collected and consequently analyzed. An illustrational decision-making scenario was used which allows the mutual comparison of all of the selected decision making methods. Our test results suggest that although all methods are convenient and can be used in practice, the VIKOR method accomplished the tests with the best results and thus can be recommended as the most suitable for simulations of large-scale agent-based models. PMID:27806061

A systematic review of statistical methods used to test for reliability of medical instruments measuring continuous variables.

PubMed

Zaki, Rafdzah; Bulgiba, Awang; Nordin, Noorhaire; Azina Ismail, Noor

2013-06-01

Reliability measures precision or the extent to which test results can be replicated. This is the first ever systematic review to identify statistical methods used to measure reliability of equipment measuring continuous variables. This studyalso aims to highlight the inappropriate statistical method used in the reliability analysis and its implication in the medical practice. In 2010, five electronic databases were searched between 2007 and 2009 to look for reliability studies. A total of 5,795 titles were initially identified. Only 282 titles were potentially related, and finally 42 fitted the inclusion criteria. The Intra-class Correlation Coefficient (ICC) is the most popular method with 25 (60%) studies having used this method followed by the comparing means (8 or 19%). Out of 25 studies using the ICC, only 7 (28%) reported the confidence intervals and types of ICC used. Most studies (71%) also tested the agreement of instruments. This study finds that the Intra-class Correlation Coefficient is the most popular method used to assess the reliability of medical instruments measuring continuous outcomes. There are also inappropriate applications and interpretations of statistical methods in some studies. It is important for medical researchers to be aware of this issue, and be able to correctly perform analysis in reliability studies.

Identification of characteristic frequencies of damaged railway tracks using field hammer test measurements

NASA Astrophysics Data System (ADS)

Oregui, M.; Li, Z.; Dollevoet, R.

2015-03-01

In this paper, the feasibility of the Frequency Response Function (FRF)-based statistical method to identify the characteristic frequencies of railway track defects is studied. The method compares a damaged track state to a healthy state based on non-destructive field hammer test measurements. First, a study is carried out to investigate the repeatability of hammer tests in railway tracks. By changing the excitation and measurement locations it is shown that the variability introduced by the test process is negligible. Second, following the concepts of control charts employed in process monitoring, a method to define an approximate healthy state is introduced by using hammer test measurements at locations without visual damage. Then, the feasibility study includes an investigation into squats (i.e. a major type of rail surface defect) of varying severity. The identified frequency ranges related to squats agree with those found in an extensively validated vehicle-borne detection system. Therefore, the FRF-based statistical method in combination with the non-destructive hammer test measurements has the potential to be employed to identify the characteristic frequencies of damaged conditions in railway tracks in the frequency range of 300-3000 Hz.

Catch-up validation study of an in vitro skin irritation test method based on an open source reconstructed epidermis (phase II).

PubMed

Groeber, F; Schober, L; Schmid, F F; Traube, A; Kolbus-Hernandez, S; Daton, K; Hoffmann, S; Petersohn, D; Schäfer-Korting, M; Walles, H; Mewes, K R

2016-10-01

To replace the Draize skin irritation assay (OECD guideline 404) several test methods based on reconstructed human epidermis (RHE) have been developed and were adopted in the OECD test guideline 439. However, all validated test methods in the guideline are linked to RHE provided by only three companies. Thus, the availability of these test models is dependent on the commercial interest of the producer. To overcome this limitation and thus to increase the accessibility of in vitro skin irritation testing, an open source reconstructed epidermis (OS-REp) was introduced. To demonstrate the capacity of the OS-REp in regulatory risk assessment, a catch-up validation study was performed. The participating laboratories used in-house generated OS-REp to assess the set of 20 reference substances according to the performance standards amending the OECD test guideline 439. Testing was performed under blinded conditions. The within-laboratory reproducibility of 87% and the inter-laboratory reproducibility of 85% prove a high reliability of irritancy testing using the OS-REp protocol. In addition, the prediction capacity was with an accuracy of 80% comparable to previous published RHE based test protocols. Taken together the results indicate that the OS-REp test method can be used as a standalone alternative skin irritation test replacing the OECD test guideline 404. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Novel MRI tests of orocecal transit time and whole gut transit time: studies in normal subjects

PubMed Central

Chaddock, G; Lam, C; Hoad, C L; Costigan, C; Cox, E F; Placidi, E; Thexton, I; Wright, J; Blackshaw, P E; Perkins, A C; Marciani, L; Gowland, P A; Spiller, R C

2014-01-01

Background Colonic transit tests are used to manage patients with Functional Gastrointestinal Disorders. Some tests used expose patients to ionizing radiation. The aim of this study was to compare novel magnetic resonance imaging (MRI) tests for measuring orocecal transit time (OCTT) and whole gut transit time (WGT), which also provide data on colonic volumes. Methods 21 healthy volunteers participated. Study 1: OCTT was determined from the arrival of the head of a meal into the cecum using MRI and the Lactose Ureide breath test (LUBT), performed concurrently. Study 2: WGT was assessed using novel MRI marker capsules and radio-opaque markers (ROMs), taken on the same morning. Studies were repeated 1 week later. Key Results OCTT measured using MRI and LUBT was 225 min (IQR 180–270) and 225 min (IQR 165–278), respectively, correlation rs = 0.28 (ns). WGT measured using MRI marker capsules and ROMs was 28 h (IQR 4–50) and 31 h ± 3 (SEM), respectively, correlation rs = 0.85 (p < 0.0001). Repeatability assessed using the intraclass correlation coefficient (ICC) was 0.45 (p = 0.017) and 0.35 (p = 0.058) for MRI and LUBT OCTT tests. Better repeatability was observed for the WGT tests, ICC being 0.61 for the MRI marker capsules (p = 0.001) and 0.69 for the ROM method (p < 0.001) respectively. Conclusions & Inferences The MRI WGT method is simple, convenient, does not use X-ray and compares well with the widely used ROM method. Both OCTT measurements showed modest reproducibility and the MRI method showed modest inter-observer agreement. PMID:24165044

Equivalence testing using existing reference data: An example with genetically modified and conventional crops in animal feeding studies.

PubMed

van der Voet, Hilko; Goedhart, Paul W; Schmidt, Kerstin

2017-11-01

An equivalence testing method is described to assess the safety of regulated products using relevant data obtained in historical studies with assumedly safe reference products. The method is illustrated using data from a series of animal feeding studies with genetically modified and reference maize varieties. Several criteria for quantifying equivalence are discussed, and study-corrected distribution-wise equivalence is selected as being appropriate for the example case study. An equivalence test is proposed based on a high probability of declaring equivalence in a simplified situation, where there is no between-group variation, where the historical and current studies have the same residual variance, and where the current study is assumed to have a sample size as set by a regulator. The method makes use of generalized fiducial inference methods to integrate uncertainties from both the historical and the current data. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Using imputed genotype data in the joint score tests for genetic association and gene-environment interactions in case-control studies.

PubMed

Song, Minsun; Wheeler, William; Caporaso, Neil E; Landi, Maria Teresa; Chatterjee, Nilanjan

2018-03-01

Genome-wide association studies (GWAS) are now routinely imputed for untyped single nucleotide polymorphisms (SNPs) based on various powerful statistical algorithms for imputation trained on reference datasets. The use of predicted allele counts for imputed SNPs as the dosage variable is known to produce valid score test for genetic association. In this paper, we investigate how to best handle imputed SNPs in various modern complex tests for genetic associations incorporating gene-environment interactions. We focus on case-control association studies where inference for an underlying logistic regression model can be performed using alternative methods that rely on varying degree on an assumption of gene-environment independence in the underlying population. As increasingly large-scale GWAS are being performed through consortia effort where it is preferable to share only summary-level information across studies, we also describe simple mechanisms for implementing score tests based on standard meta-analysis of "one-step" maximum-likelihood estimates across studies. Applications of the methods in simulation studies and a dataset from GWAS of lung cancer illustrate ability of the proposed methods to maintain type-I error rates for the underlying testing procedures. For analysis of imputed SNPs, similar to typed SNPs, the retrospective methods can lead to considerable efficiency gain for modeling of gene-environment interactions under the assumption of gene-environment independence. Methods are made available for public use through CGEN R software package. © 2017 WILEY PERIODICALS, INC.

DC/DC Converter Stability Testing Study

NASA Technical Reports Server (NTRS)

Wang, Bright L.

2008-01-01

This report presents study results on hybrid DC/DC converter stability testing methods. An input impedance measurement method and a gain/phase margin measurement method were evaluated to be effective to determine front-end oscillation and feedback loop oscillation. In particular, certain channel power levels of converter input noises have been found to have high degree correlation with the gain/phase margins. It becomes a potential new method to evaluate stability levels of all type of DC/DC converters by utilizing the spectral analysis on converter input noises.

Operational methods of HIV testing in emergency departments: a systematic review.

PubMed

Haukoos, Jason S; White, Douglas A E; Lyons, Michael S; Hopkins, Emily; Calderon, Yvette; Kalish, Brian; Rothman, Richard E

2011-07-01

Casual review of existing literature reveals a multitude of individualized approaches to emergency department (ED) HIV testing. Cataloging the operational options of each approach could assist translation by disseminating existing knowledge, endorsing variability as a means to address testing barriers, and laying a foundation for future work in the area of operational models and outcomes investigation. The objective of this study is to provide a detailed account of the various models and operational constructs that have been described for performing HIV testing in EDs. Systematic review of PUBMED, EMBASE, the Cumulative Index to Nursing and Allied Health Literature (CINAHL), and the Web of Science through February 6, 2009 was performed. Three investigators independently reviewed all potential abstracts and identified all studies that met the following criteria for inclusion: original research, performance of HIV testing in an ED in the United States, description of operational methods, and reporting of specific testing outcomes. Each study was independently assessed and data from each were abstracted with standardized instruments. Summary and pooled descriptive statistics were reported by using recently published nomenclature and definitions for ED HIV testing. The primary search yielded 947 potential studies, of which 25 (3%) were included in the final analysis. Of the 25 included studies, 13 (52%) reported results using nontargeted screening as the only patient selection method. Most programs reported using voluntary, opt-in consent and separate, signed consent forms. A variety of assays and communication methods were used, but relatively limited outcomes data were reported. Currently, limited evidence exists to inform HIV testing practices in EDs. There appears to be recent progression toward the use of rapid assays and nontargeted patient selection methods, with the rate at which reports are published in the peer-reviewed literature increasing. Additional research will be required, including controlled clinical trials, more structured program evaluation, and a focus on an expanded profile of outcome measures, to further improve our understanding of which HIV testing methods are most effective in the ED. Copyright © 2011. Published by Mosby, Inc.

The Effect of Pilates Exercise on Trunk and Postural Stability and Throwing Velocity in College Baseball Pitchers: Single Subject Design

PubMed Central

Howe, Katherine

2007-01-01

Background Baseball pitchers need trunk strength to maximize performance. The Pilates method of exercise is gaining popularity throughout the country as a fitness and rehabilitation method of exercise. However, very few studies exist that examine the effects of the Pilates method of exercise on trunk strength or performance. Objectives Using a single subject, multiple baseline across subjects design, this study examines the effects of the Pilates method of exercise on performance of double leg lowering, star excursion balance test, and throwing velocity in college-aged baseball pitchers. Methods A convenience sample of three college baseball pitchers served as the subjects for this single subject design study. For each subject, double leg lowering, star excursion balance test, and throwing speed were measured prior to the introduction of the intervention. When baseline test values showed consistent performance, the intervention was introduced to one subject at a time. Intervention was introduced to the other subjects over a period of 4 weeks as they also demonstrated consistent performance on the baseline tests. Intervention was continued with periodic tests for the remainder of the 10 week trial. Results Each subject improved in performance on double leg lowering (increased 24.43-32.7%) and star excursion balance test (increased 4.63-17.84%) after introduction of the intervention. Throwing speed improved in two of the three subjects (up to 5.61%). Discussion and Conclusions The Pilates method of exercise may contribute to improved performance in double leg lowering, star excursion balance tests, and throwing speed in college baseball pitchers. PMID:21522199

A Retrospective Performance Assessment of the Developmental Neurotoxicity Study in Support of OECD Test Guideline 426

PubMed Central

Makris, Susan L.; Raffaele, Kathleen; Allen, Sandra; Bowers, Wayne J.; Hass, Ulla; Alleva, Enrico; Calamandrei, Gemma; Sheets, Larry; Amcoff, Patric; Delrue, Nathalie; Crofton, Kevin M.

2009-01-01

Objective We conducted a review of the history and performance of developmental neurotoxicity (DNT) testing in support of the finalization and implementation of Organisation of Economic Co-operation and Development (OECD) DNT test guideline 426 (TG 426). Information sources and analysis In this review we summarize extensive scientific efforts that form the foundation for this testing paradigm, including basic neurotoxicology research, interlaboratory collaborative studies, expert workshops, and validation studies, and we address the relevance, applicability, and use of the DNT study in risk assessment. Conclusions The OECD DNT guideline represents the best available science for assessing the potential for DNT in human health risk assessment, and data generated with this protocol are relevant and reliable for the assessment of these end points. The test methods used have been subjected to an extensive history of international validation, peer review, and evaluation, which is contained in the public record. The reproducibility, reliability, and sensitivity of these methods have been demonstrated, using a wide variety of test substances, in accordance with OECD guidance on the validation and international acceptance of new or updated test methods for hazard characterization. Multiple independent, expert scientific peer reviews affirm these conclusions. PMID:19165382

Comparison of Quantitative Antifungal Testing Methods for Textile Fabrics.

PubMed

Imoto, Yasuo; Seino, Satoshi; Nakagawa, Takashi; Yamamoto, Takao A

2017-01-01

　Quantitative antifungal testing methods for textile fabrics under growth-supportive conditions were studied. Fungal growth activities on unfinished textile fabrics and textile fabrics modified with Ag nanoparticles were investigated using the colony counting method and the luminescence method. Morphological changes of the fungi during incubation were investigated by microscopic observation. Comparison of the results indicated that the fungal growth activity values obtained with the colony counting method depended on the morphological state of the fungi on textile fabrics, whereas those obtained with the luminescence method did not. Our findings indicated that unique characteristics of each testing method must be taken into account for the proper evaluation of antifungal activity.

Effects of Content Balancing and Item Selection Method on Ability Estimation in Computerized Adaptive Tests

ERIC Educational Resources Information Center

Sahin, Alper; Ozbasi, Durmus

2017-01-01

Purpose: This study aims to reveal effects of content balancing and item selection method on ability estimation in computerized adaptive tests by comparing Fisher's maximum information (FMI) and likelihood weighted information (LWI) methods. Research Methods: Four groups of examinees (250, 500, 750, 1000) and a bank of 500 items with 10 different…

A comparison of interteaching and lecture in the college classroom.

PubMed

Saville, Bryan K; Zinn, Tracy E; Neef, Nancy A; Van Norman, Renee; Ferreri, Summer J

2006-01-01

Interteaching is a new method of classroom instruction that is based on behavioral principles but offers more flexibility than other behaviorally based methods. We examined the effectiveness of interteaching relative to a traditional form of classroom instruction-the lecture. In Study 1, participants in a graduate course in special education took short quizzes after alternating conditions of interteaching and lecture. Quiz scores following interteaching were higher than quiz scores following lecture, although both methods improved performance relative to pretest measures. In Study 2, we also alternated interteaching and lecture but counterbalanced the conditions across two sections of an undergraduate research methods class. After each unit of information, participants from both sections took the same test. Again, test scores following interteaching were higher than test scores following lecture. In addition, students correctly answered more interteaching-based questions than lecture-based questions on a cumulative final test. In both studies, the majority of students reported a preference for interteaching relative to traditional lecture. In sum, the results suggest that interteaching may be an effective alternative to traditional lecture-based methods of instruction.

Research of laser stealth performance test technology

NASA Astrophysics Data System (ADS)

Chen, Zhen-xing; Shi, Sheng-bing; Han, Fu-li; Wu, Yan-lin; Song, Chun-yan

2014-09-01

Laser stealth is an important way of photoelectric stealth weapons systems. According to operational principle of laser range finder, we actively explore and study the stealth performance approval testing technology of laser stealth materials, and bring forward and establish the stealth performance field test methods of stealth efficiency evaluation. Through contrastive test of two kinds of materials, the method is correct and effective.

A study on scattering correction for γ-photon 3D imaging test method

NASA Astrophysics Data System (ADS)

Xiao, Hui; Zhao, Min; Liu, Jiantang; Chen, Hao

2018-03-01

A pair of 511KeV γ-photons is generated during a positron annihilation. Their directions differ by 180°. The moving path and energy information can be utilized to form the 3D imaging test method in industrial domain. However, the scattered γ-photons are the major factors influencing the imaging precision of the test method. This study proposes a γ-photon single scattering correction method from the perspective of spatial geometry. The method first determines possible scattering points when the scattered γ-photon pair hits the detector pair. The range of scattering angle can then be calculated according to the energy window. Finally, the number of scattered γ-photons denotes the attenuation of the total scattered γ-photons along its moving path. The corrected γ-photons are obtained by deducting the scattered γ-photons from the original ones. Two experiments are conducted to verify the effectiveness of the proposed scattering correction method. The results concluded that the proposed scattering correction method can efficiently correct scattered γ-photons and improve the test accuracy.

Toxicity assessment of industrial chemicals and airborne contaminants: transition from in vivo to in vitro test methods: a review.

PubMed

Bakand, S; Winder, C; Khalil, C; Hayes, A

2005-12-01

Exposure to occupational and environmental contaminants is a major contributor to human health problems. Inhalation of gases, vapors, aerosols, and mixtures of these can cause a wide range of adverse health effects, ranging from simple irritation to systemic diseases. Despite significant achievements in the risk assessment of chemicals, the toxicological database, particularly for industrial chemicals, remains limited. Considering there are approximately 80,000 chemicals in commerce, and an extremely large number of chemical mixtures, in vivo testing of this large number is unachievable from both economical and practical perspectives. While in vitro methods are capable of rapidly providing toxicity information, regulatory agencies in general are still cautious about the replacement of whole-animal methods with new in vitro techniques. Although studying the toxic effects of inhaled chemicals is a complex subject, recent studies demonstrate that in vitro methods may have significant potential for assessing the toxicity of airborne contaminants. In this review, current toxicity test methods for risk evaluation of industrial chemicals and airborne contaminants are presented. To evaluate the potential applications of in vitro methods for studying respiratory toxicity, more recent models developed for toxicity testing of airborne contaminants are discussed.

A comparative laboratory diagnosis of malaria: microscopy versus rapid diagnostic test kits.

PubMed

Azikiwe, C C A; Ifezulike, C C; Siminialayi, I M; Amazu, L U; Enye, J C; Nwakwunite, O E

2012-04-01

To compare the two methods of rapid diagnostic tests (RDTs) and microscopy in the diagnosis of malaria. RDTs and microscopy were carried out to diagnose malaria. Percentage malaria parasitaemia was calculated on thin films and all non-acute cases of plasmodiasis with less than 0.001% malaria parasitaemia were regarded as negative. Results were simply presented as percentage positive of the total number of patients under study. The results of RDTs were compared to those of microscopy while those of RDTs based on antigen were compared to those of RDTs based on antibody. Patients' follow-up was made for all cases. All the 200 patients under present study tested positive to RDTs based on malaria antibodies (serum) method (100%). 128 out of 200 tested positive to RDTs based on malaria antigen (whole blood) method (64%), while 118 out of 200 patients under present study tested positive to visual microscopy of Lieshman and diluted Giemsa (59%). All patients that tested positive to microscopy also tested positive to RDTs based on antigen. All patients on the second day of follow-up were non-febrile and had antimalaria drugs. We conclude based on the present study that the RDTs based on malaria antigen (whole blood) method is as specific as the traditional microscopy and even appears more sensitive than microscopy. The RDTs based on antibody (serum) method is unspecific thus it should not be encouraged. It is most likely that Africa being an endemic region, formation of certain levels of malaria antibody may not be uncommon. The present study also supports the opinion that a good number of febrile cases is not due to malaria. We support WHO's report on cost effectiveness of RDTs but, recommend that only the antigen based method should possibly, be adopted in Africa and other malaria endemic regions of the world.

Compensation of kinematic geometric parameters error and comparative study of accuracy testing for robot

NASA Astrophysics Data System (ADS)

Du, Liang; Shi, Guangming; Guan, Weibin; Zhong, Yuansheng; Li, Jin

2014-12-01

Geometric error is the main error of the industrial robot, and it plays a more significantly important fact than other error facts for robot. The compensation model of kinematic error is proposed in this article. Many methods can be used to test the robot accuracy, therefore, how to compare which method is better one. In this article, a method is used to compare two methods for robot accuracy testing. It used Laser Tracker System (LTS) and Three Coordinate Measuring instrument (TCM) to test the robot accuracy according to standard. According to the compensation result, it gets the better method which can improve the robot accuracy apparently.

Sensitivity for Diagnosing Group A Streptococcal Pharyngitis from Manufacturers is 10% Higher than Reported in Peer-Reviewed Publications.

PubMed

Vachhani, Raj; Patel, Toral; Centor, Robert M; Estrada, Carlos A

2017-01-01

Meta-analyses based on peer-reviewed publications report a sensitivity of approximately 85% for rapid antigen streptococcus tests to diagnose group A streptococcal (GAS) pharyngitis. Because these meta-analyses excluded package inserts, we examined the test characteristics of rapid antigen streptococcal tests and molecular methods that manufacturers report in their package inserts. We included tests available in the US market (Food and Drug Administration, period searched 1993-2015) and used package insert data to calculate pooled sensitivity and specificity. To examine quality, we used the Quality Assessment of Diagnostic Accuracy Studies-2. We excluded 26 tests having different trade names but identical methods and data. The study design was prospective in 41.7% (10 of 24). The pooled sensitivity of the most commonly used method, lateral flow/immunochromatographic, was 95% (95% confidence interval [CI] 94-96) and the pooled specificity was 98% (96-98); 7108 patients. The pooled sensitivity of the polymerase chain reaction or molecular methods was 98% (95% CI 96-98) and the pooled specificity was 96% (95% CI 95-97); 5685 patients. Package inserts include sponsored studies that overestimate the sensitivity of rapid tests to diagnose GAS pharyngitis by approximately 10%. Physicians should understand that package inserts overestimate diagnostic test utility; a negative test cannot be used to exclude GAS pharyngitis.

Diagnostic Performance of a Molecular Test versus Clinician Assessment of Vaginitis

PubMed Central

Gaydos, Charlotte A.; Nyirjesy, Paul; Paradis, Sonia; Kodsi, Salma; Cooper, Charles K.

2018-01-01

ABSTRACT Vaginitis is a common complaint, diagnosed either empirically or using Amsel's criteria and wet mount microscopy. This study sought to determine characteristics of an investigational test (a molecular test for vaginitis), compared to reference, for detection of bacterial vaginosis, Candida spp., and Trichomonas vaginalis. Vaginal specimens from a cross-sectional study were obtained from 1,740 women (≥18 years old), with vaginitis symptoms, during routine clinic visits (across 10 sites in the United States). Specimens were analyzed using a commercial PCR/fluorogenic probe-based investigational test that detects bacterial vaginosis, Candida spp., and Trichomonas vaginalis. Clinician diagnosis and in-clinic testing (Amsel's test, potassium hydroxide preparation, and wet mount) were also employed to detect the three vaginitis causes. All testing methods were compared to the respective reference methods (Nugent Gram stain for bacterial vaginosis, detection of the Candida gene its2, and Trichomonas vaginalis culture). The investigational test, clinician diagnosis, and in-clinic testing were compared to reference methods for bacterial vaginosis, Candida spp., and Trichomonas vaginalis. The investigational test resulted in significantly higher sensitivity and negative predictive value than clinician diagnosis or in-clinic testing. In addition, the investigational test showed a statistically higher overall percent agreement with each of the three reference methods than did clinician diagnosis or in-clinic testing. The investigational test showed significantly higher sensitivity for detecting vaginitis, involving more than one cause, than did clinician diagnosis. Taken together, these results suggest that a molecular investigational test can facilitate accurate detection of vaginitis. PMID:29643195

Applied Chaos Level Test for Validation of Signal Conditions Underlying Optimal Performance of Voice Classification Methods.

PubMed

Liu, Boquan; Polce, Evan; Sprott, Julien C; Jiang, Jack J

2018-05-17

The purpose of this study is to introduce a chaos level test to evaluate linear and nonlinear voice type classification method performances under varying signal chaos conditions without subjective impression. Voice signals were constructed with differing degrees of noise to model signal chaos. Within each noise power, 100 Monte Carlo experiments were applied to analyze the output of jitter, shimmer, correlation dimension, and spectrum convergence ratio. The computational output of the 4 classifiers was then plotted against signal chaos level to investigate the performance of these acoustic analysis methods under varying degrees of signal chaos. A diffusive behavior detection-based chaos level test was used to investigate the performances of different voice classification methods. Voice signals were constructed by varying the signal-to-noise ratio to establish differing signal chaos conditions. Chaos level increased sigmoidally with increasing noise power. Jitter and shimmer performed optimally when the chaos level was less than or equal to 0.01, whereas correlation dimension was capable of analyzing signals with chaos levels of less than or equal to 0.0179. Spectrum convergence ratio demonstrated proficiency in analyzing voice signals with all chaos levels investigated in this study. The results of this study corroborate the performance relationships observed in previous studies and, therefore, demonstrate the validity of the validation test method. The presented chaos level validation test could be broadly utilized to evaluate acoustic analysis methods and establish the most appropriate methodology for objective voice analysis in clinical practice.

How Management Information Systems Can Enhance the Air Force Drug Testing Program

DTIC Science & Technology

1989-12-01

promising processes to positively identify potential system users (46:401). Scope This study will cover issues concerning the Air Force drug testing...7 Scope....................10 Limitations of the Research . . . 10 Investigative Questions ............ 10 Expected Benefits of the Study . . . . 11...Resource Allocation. ....... 41 M1.>ethodology....................44 The Historical Research Method . . .. 44 The Historical Research Method for this Study

EPA flow reference method testing and analysis: Data report -- Pennsylvania Electric Company, G.P.U. Genco Homer City Station. Volume 1: Test description and appendix A (data distribution package)

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

NONE

1998-09-01

This report describes the test site, equipment, and procedures and presents the data obtained during field testing at G.P.U. Genco Homer City Station, August 19--24, 1997. This was the third of three field tests that the US Environmental Protection Agency (EPA) conducted in 1997 as part of a major study to evaluate potential improvements to Method 3, EPA`s test method for measuring flue gas volumetric flow in stacks. The report also includes a Data Distribution Package, the official, complete repository of the results obtained at the test site.

Preliminary evaluation of a gel tube agglutination major cross-match method in dogs.

PubMed

Villarnovo, Dania; Burton, Shelley A; Horney, Barbara S; MacKenzie, Allan L; Vanderstichel, Raphaël

2016-09-01

A major cross-match gel tube test is available for use in dogs yet has not been clinically evaluated. This study compared cross-match results obtained using the gel tube and the standard tube methods for canine samples. Study 1 included 107 canine sample donor-recipient pairings cross-match tested with the RapidVet-H method gel tube test and compared results with the standard tube method. Additionally, 120 pairings using pooled sera containing anti-canine erythrocyte antibody at various concentrations were tested with leftover blood from a hospital population to assess sensitivity and specificity of the gel tube method in comparison with the standard method. The gel tube method had a good relative specificity of 96.1% in detecting lack of agglutination (compatibility) compared to the standard tube method. Agreement between the 2 methods was moderate. Nine of 107 pairings showed agglutination/incompatibility on either test, too few to allow reliable calculation of relative sensitivity. Fifty percent of the gel tube method results were difficult to interpret due to sample spreading in the reaction and/or negative control tubes. The RapidVet-H method agreed with the standard cross-match method on compatible samples, but detected incompatibility in some sample pairs that were compatible with the standard method. Evaluation using larger numbers of incompatible pairings is needed to assess diagnostic utility. The gel tube method results were difficult to categorize due to sample spreading. Weak agglutination reactions or other factors such as centrifuge model may be responsible. © 2016 American Society for Veterinary Clinical Pathology.

A conjugate gradient method with descent properties under strong Wolfe line search

NASA Astrophysics Data System (ADS)

Zull, N.; ‘Aini, N.; Shoid, S.; Ghani, N. H. A.; Mohamed, N. S.; Rivaie, M.; Mamat, M.

2017-09-01

The conjugate gradient (CG) method is one of the optimization methods that are often used in practical applications. The continuous and numerous studies conducted on the CG method have led to vast improvements in its convergence properties and efficiency. In this paper, a new CG method possessing the sufficient descent and global convergence properties is proposed. The efficiency of the new CG algorithm relative to the existing CG methods is evaluated by testing them all on a set of test functions using MATLAB. The tests are measured in terms of iteration numbers and CPU time under strong Wolfe line search. Overall, this new method performs efficiently and comparable to the other famous methods.

Roche/BIOTECON Diagnostics LightCycler foodproof L. monocytogenes detection kit in combination with ShortPrep foodproof II Kit. Performance-Tested Method 070401.

PubMed

Junge, Benjamin; Berghof-Jäger, Kornelia

2006-01-01

A method was developed for the detection of L. monocytogenes in food based on real-time polymerase chain reaction (PCR). This advanced PCR method was designed to reduce the time needed to achieve results from PCR reactions and to enable the user to monitor the amplification of the PCR product simultaneously, in real-time. After DNA isolation using the Roche/BIOTECON Diagnostics ShortPrep foodproof II Kit (formerly called Listeria ShortPrep Kit) designed for the rapid preparation of L. monocytogenes DNA for direct use in PCR, the real-time detection of L. monocytogenes DNA is performed by using the Roche/BIOTECON Diagnostics LightCycler foodproof L. monocytogenes Detection Kit. This kit provides primers and hybridization probes for sequence-specific detection, convenient premixed reagents, and different controls for reliable interpretation of results. For repeatability studies, 20 different foods, covering the 15 food groups recommended from the AOAC Research Institute (AOAC RI) for L. monocytogenes detection were analyzed: raw meats, fresh produce/vegetables, processed meats, seafood, egg and egg products, dairy (cultured/noncultured), spices, dry foods, fruit/juices, uncooked pasta, nuts, confectionery, pet food, food dyes and colorings, and miscellaneous. From each food 20, samples were inoculated with a low level (1-10 colony-forming units (CFU)/25 g) and 20 samples with a high level (10-50 CFU/25 g) of L. monocytogenes. Additionally, 5 uninoculated samples were prepared from each food. The food samples were examined with the test kits and in correlation with the cultural methods according to U.S. Food and Drug Administration (FDA) Bacteriological Analytical Manual (BAM) or U.S. Department of Agriculture (USDA)/Food Safety and Inspection Service (FSIS) Microbiology Laboratory Guidebook. After 48 h of incubation, the PCR method in all cases showed equal or better results than the reference cultural FDA/BAM or USDA/FSIS methods. Fifteen out of 20 tested food types gave exactly the same amount of positive samples for both methods in both inoculation levels. For 5 out of 20 foodstuffs, the PCR method resulted in more positives than the reference method after 48 h of incubation. Following AOAC RI definition, these were false positives because they were not confirmed by the reference method (false-positive rate for low inoculated foodstuffs: 5.4%; for high inoculated foodstuffs: 7.1%). Without calculating these unconfirmed positives, the PCR method showed equal sensitivity results compared to the alternative method. With the unconfirmed PCR-positives included into the calculations, the alternative PCR method showed a higher sensitivity than the microbiological methods (low inoculation level: 100 vs 98.0%; sensitivity rate: 1; high inoculation level: 99.7 vs 97.7%; sensitivity rate, 1). All in-house and independently tested uninoculated food samples were negative for L. monocytogenes. The ruggedness testing of both ShortPrep foodproof II Kit and Roche/BIOTECON LightCycler foodproof L. monocytogenes Detection Kit showed no noteworthy influences to any variation of the parameters component concentration, apparatus comparison, tester comparison, and sample volumes. In total, 102 L. monocytogenes isolates (cultures and pure DNA) were tested and detected for the inclusivity study, including all isolates claimed by the AOAC RI. The exclusivity study included 60 non-L. monocytogenes bacteria. None of the tested isolates gave a false-positive result; specificity was 100%. Three different lots were tested in the lot-to-lot study. All 3 lots gave equal results. The stability study was subdivided into 3 parts: long-term study, stress test, and freeze-defrost test. Three lots were tested in 4 time intervals within a period of 13 months. They all gave comparable results for all test intervals. For the stress test, LightCycler L. monocytogenes detection mixes were stored at different temperatures and tested at different time points during 1 month. Stable results were produced at all storage temperatures. The freeze-defrost analysis showed no noteworthy aggravation of test results. The independent validation study examined by Campden and Chorleywood Food Research Association Group (CCFRA) demonstrated again that the LightCycler L. monocytogenes detection system shows a comparable sensitivity to reference methods. With both the LightCycler PCR and BAM methods, 19 out of 20 inoculated food samples were detected. The 24 h PCR results generated by the LightCycler system corresponded directly with the FDA/BAM culture results. However, the 48 h PCR results did not relate exactly to the FDA/BAM results, as one sample found to be positive by the 48 h PCR could not be culturally confirmed and another sample which was negative by the 48 h PCR was culturally positive.

Product Quality Research Institute evaluation of cascade impactor profiles of pharmaceutical aerosols: part 2--evaluation of a method for determining equivalence.

PubMed

Christopher, David; Adams, Wallace P; Lee, Douglas S; Morgan, Beth; Pan, Ziqing; Singh, Gur Jai Pal; Tsong, Yi; Lyapustina, Svetlana

2007-01-19

The purpose of this article is to present the thought process, methods, and interim results of a PQRI Working Group, which was charged with evaluating the chi-square ratio test as a potential method for determining in vitro equivalence of aerodynamic particle size distribution (APSD) profiles obtained from cascade impactor measurements. Because this test was designed with the intention of being used as a tool in regulatory review of drug applications, the capability of the test to detect differences in APSD profiles correctly and consistently was evaluated in a systematic way across a designed space of possible profiles. To establish a "base line," properties of the test in the simplest case of pairs of identical profiles were studied. Next, the test's performance was studied with pairs of profiles, where some difference was simulated in a systematic way on a single deposition site using realistic product profiles. The results obtained in these studies, which are presented in detail here, suggest that the chi-square ratio test in itself is not sufficient to determine equivalence of particle size distributions. This article, therefore, introduces the proposal to combine the chi-square ratio test with a test for impactor-sized mass based on Population Bioequivalence and describes methods for evaluating discrimination capabilities of the combined test. The approaches and results described in this article elucidate some of the capabilities and limitations of the original chi-square ratio test and provide rationale for development of additional tests capable of comparing APSD profiles of pharmaceutical aerosols.

Comparison of a New and Rapid Method: Brucella Coombs Gel Test With Other Diagnostic Tests.

PubMed

Kalem, Fatma; Ergün, Ayşe Gül; Durmaz, Süleyman; Doğan, Metin; Ertuğrul, Ömür; Gündem, Seval

2016-09-01

The aim of this study was to detect reliability of Brucella Coombs gel test (BCGT) by comparing with with ELISA (IgG + IgM), Standard agglutination test, and Brucella immunocapture agglutination methods in serological diagnosis of brucellosis. Brucella Coombs gel test (BCGT), Brucella ELISA (IgG + IgM), Standard agglutination test, and Brucella immunocapture agglutination tests of 78 patients with presumptive diagnosis of brucellosis which were sent to Microbiology Laboratory of Konya Numune Hospital from various regions of Konya were studied. Of 78 patients with ELISA IgG and IgM, STA, BICA and BCGT; 26, 21, 10, 12 and 12 were positive. When compared with BICA, the sensitivity and specifity of BCGT were 100% and 100%, respectively. According to results BCGT can be used as a diagnostic test in routine laboratories after more comprehensive studies in control groups and patients. © 2016 Wiley Periodicals, Inc.

Testing prediction methods: Earthquake clustering versus the Poisson model

USGS Publications Warehouse

Michael, A.J.

1997-01-01

Testing earthquake prediction methods requires statistical techniques that compare observed success to random chance. One technique is to produce simulated earthquake catalogs and measure the relative success of predicting real and simulated earthquakes. The accuracy of these tests depends on the validity of the statistical model used to simulate the earthquakes. This study tests the effect of clustering in the statistical earthquake model on the results. Three simulation models were used to produce significance levels for a VLF earthquake prediction method. As the degree of simulated clustering increases, the statistical significance drops. Hence, the use of a seismicity model with insufficient clustering can lead to overly optimistic results. A successful method must pass the statistical tests with a model that fully replicates the observed clustering. However, a method can be rejected based on tests with a model that contains insufficient clustering. U.S. copyright. Published in 1997 by the American Geophysical Union.

A new alternative method for testing skin irritation using a human skin model: a pilot study.

PubMed

Miles, A; Berthet, A; Hopf, N B; Gilliet, M; Raffoul, W; Vernez, D; Spring, P

2014-03-01

Studies assessing skin irritation to chemicals have traditionally used laboratory animals; however, such methods are questionable regarding their relevance for humans. New in vitro methods have been validated, such as the reconstructed human epidermis (RHE) model (Episkin®, Epiderm®). The comparison (accuracy) with in vivo results such as the 4-h human patch test (HPT) is 76% at best (Epiderm®). There is a need to develop an in vitro method that better simulates the anatomo-pathological changes encountered in vivo. To develop an in vitro method to determine skin irritation using human viable skin through histopathology, and compare the results of 4 tested substances to the main in vitro methods and in vivo animal method (Draize test). Human skin removed during surgery was dermatomed and mounted on an in vitro flow-through diffusion cell system. Ten chemicals with known non-irritant (heptylbutyrate, hexylsalicylate, butylmethacrylate, isoproturon, bentazon, DEHP and methylisothiazolinone (MI)) and irritant properties (folpet, 1-bromohexane and methylchloroisothiazolinone (MCI/MI)), a negative control (sodiumchloride) and a positive control (sodiumlaurylsulphate) were applied. The skin was exposed at least for 4h. Histopathology was performed to investigate irritation signs (spongiosis, necrosis, vacuolization). We obtained 100% accuracy with the HPT model; 75% with the RHE models and 50% with the Draize test for 4 tested substances. The coefficients of variation (CV) between our three test batches were <0.1, showing good reproducibility. Furthermore, we reported objectively histopathological irritation signs (irritation scale): strong (folpet), significant (1-bromohexane), slight (MCI/MI at 750/250ppm) and none (isoproturon, bentazon, DEHP and MI). This new in vitro test method presented effective results for the tested chemicals. It should be further validated using a greater number of substances; and tested in different laboratories in order to suitably evaluate reproducibility. Copyright © 2013 Elsevier Ltd. All rights reserved.

Students Perception on the Use of Computer Based Test

NASA Astrophysics Data System (ADS)

Nugroho, R. A.; Kusumawati, N. S.; Ambarwati, O. C.

2018-02-01

Teaching nowadays might use technology in order to disseminate science and knowledge. As part of teaching, the way evaluating study progress and result has also benefited from this IT rapid progress. The computer-based test (CBT) has been introduced to replace the more conventional Paper and Pencil Test (PPT). CBT are considered more advantageous than PPT. It is considered as more efficient, transparent, and has the ability of minimising fraud in cognitive evaluation. Current studies have indicated the debate of CBT vs PPT usage. Most of the current research compares the two methods without exploring the students’ perception about the test. This study will fill the gap in the literature by providing students’ perception on the two tests method. Survey approach is conducted to obtain the data. The sample is collected in two identical classes with similar subject in a public university in Indonesia. Mann-Whitney U test used to analyse the data. The result indicates that there is a significant difference between two groups of students regarding CBT usage. Student with different test method prefers to have test other than what they were having. Further discussion and research implication is discussed in the paper.

CAT Procedures for Passage-Based Tests.

ERIC Educational Resources Information Center

Thompson, Tony D.; Davey, Tim

Methods to control the test construct and the efficiency of a computerized adaptive test (CAT) were studied in the context of a reading comprehension test given as a part of a battery of tests for college admission. A goal of the study was to create test scores that were interchangeable with those from a fixed form paper and pencil test. The first…

Modification of the BAX System PCR assay for detecting Salmonella in beef, produce, and soy protein isolate. Performance Tested Method 100201.

PubMed

Peng, Linda X; Wallace, Morgan; Andaloro, Bridget; Fallon, Dawn; Fleck, Lois; Delduco, Dan; Tice, George

2011-01-01

The BAX System PCR assay for Salmonella detection in foods was previously validated as AOAC Research Institute (RI) Performance Tested Method (PTM) 100201. New studies were conducted on beef and produce using the same media and protocol currently approved for the BAX System PCR assay for E. coli O157:H7 multiplex (MP). Additionally, soy protein isolate was tested for matrix extension using the U.S. Food and Drug Administration-Bacteriological Analytical Manual (FDA-BAM) enrichment protocols. The studies compared the BAX System method to the U.S. Department of Agriculture culture method for detecting Salmonella in beef and the FDA-BAM culture method for detecting Salmonella in produce and soy protein isolate. Method comparison studies on low-level inoculates showed that the BAX System assay for Salmonella performed as well as or better than the reference method for detecting Salmonella in beef and produce in 8-24 h enrichment when the BAX System E. coli O157:H7 MP media was used, and soy protein isolate in 20 h enrichment with lactose broth followed by 3 h regrowth in brain heart infusion broth. An inclusivity panel of 104 Salmonella strains with diverse serotypes was tested by the BAX System using the proprietary BAX System media and returned all positive results. Ruggedness factors involved in the enrichment phase were also evaluated by testing outside the specified parameters, and none of the factors examined affected the performance of the assay.

Absorbing Software Testing into the Scrum Method

NASA Astrophysics Data System (ADS)

Tuomikoski, Janne; Tervonen, Ilkka

In this paper we study, how to absorb software testing into the Scrum method. We conducted the research as an action research during the years 2007-2008 with three iterations. The result showed that testing can and even should be absorbed to the Scrum method. The testing team was merged into the Scrum teams. The teams can now deliver better working software in a shorter time, because testing keeps track of the progress of the development. Also the team spirit is higher, because the Scrum team members are committed to the same goal. The biggest change from test manager’s point of view was the organized Product Owner Team. Test manager don’t have testing team anymore, and in the future all the testing tasks have to be assigned through the Product Backlog.

Simple F Test Reveals Gene-Gene Interactions in Case-Control Studies

PubMed Central

Chen, Guanjie; Yuan, Ao; Zhou, Jie; Bentley, Amy R.; Adeyemo, Adebowale; Rotimi, Charles N.

2012-01-01

Missing heritability is still a challenge for Genome Wide Association Studies (GWAS). Gene-gene interactions may partially explain this residual genetic influence and contribute broadly to complex disease. To analyze the gene-gene interactions in case-control studies of complex disease, we propose a simple, non-parametric method that utilizes the F-statistic. This approach consists of three steps. First, we examine the joint distribution of a pair of SNPs in cases and controls separately. Second, an F-test is used to evaluate the ratio of dependence in cases to that of controls. Finally, results are adjusted for multiple tests. This method was used to evaluate gene-gene interactions that are associated with risk of Type 2 Diabetes among African Americans in the Howard University Family Study. We identified 18 gene-gene interactions (P < 0.0001). Compared with the commonly-used logistical regression method, we demonstrate that the F-ratio test is an efficient approach to measuring gene-gene interactions, especially for studies with limited sample size. PMID:22837643

Comparison of shear test methods for evaluating the bond strength of resin cement to zirconia ceramic.

PubMed

Kim, Jae-Hoon; Chae, Soyeon; Lee, Yunhee; Han, Geum-Jun; Cho, Byeong-Hoon

2014-11-01

This study compared the sensitivity of three shear test methods for measuring the shear bond strength (SBS) of resin cement to zirconia ceramic and evaluated the effects of surface treatment methods on the bonding. Polished zirconia ceramic (Cercon base, DeguDent) discs were randomly divided into four surface treatment groups: no treatment (C), airborne-particle abrasion (A), conditioning with Alloy primer (Kuraray Medical Co.) (P) and conditioning with Alloy primer after airborne-particle abrasion (AP). The bond strengths of the resin cement (Multilink N, Ivoclar Vivadent) to the zirconia specimens of each surface treatment group were determined by three SBS test methods: the conventional SBS test with direct filling of the mold (Ø 4 mm × 3 mm) with resin cement (Method 1), the conventional SBS test with cementation of composite cylinders (Ø 4 mm × 3 mm) using resin cement (Method 2) and the microshear bond strength (μSBS) test with cementation of composite cylinders (Ø 0.8 mm × 1 mm) using resin cement (Method 3). Both the test method and the surface treatment significantly influenced the SBS values. In Method 3, as the SBS values increased, the coefficients of variation decreased and the Weibull parameters increased. The AP groups showed the highest SBS in all of the test methods. Only in Method 3 did the P group show a higher SBS than the A group. The μSBS test was more sensitive to differentiating the effects of surface treatment methods than the conventional SBS tests. Primer conditioning was a stronger contributing factor for the resin bond to zirconia ceramic than was airborne-particle abrasion.

Antifungal susceptibility testing of Malassezia yeast: comparison of two different methodologies.

PubMed

Rojas, Florencia D; Córdoba, Susana B; de Los Ángeles Sosa, María; Zalazar, Laura C; Fernández, Mariana S; Cattana, María E; Alegre, Liliana R; Carrillo-Muñoz, Alfonso J; Giusiano, Gustavo E

2017-02-01

All Malassezia species are lipophilic; thus, modifications are required in susceptibility testing methods to ensure their growth. Antifungal susceptibility of Malassezia species using agar and broth dilution methods has been studied. Currently, few tests using disc diffusion methods are being performed. The aim was to evaluate the in vitro susceptibility of Malassezia yeast against antifungal agents using broth microdilution and disc diffusion methods, then to compare both methodologies. Fifty Malassezia isolates were studied. Microdilution method was performed as described in reference document and agar diffusion test was performed using antifungal tablets and discs. To support growth, culture media were supplemented. To correlate methods, linear regression analysis and categorical agreement was determined. The strongest linear association was observed for fluconazole and miconazole. The highest agreement between both methods was observed for itraconazole and voriconazole and the lowest for amphotericin B and fluconazole. Although modifications made to disc diffusion method allowed to obtain susceptibility data for Malassezia yeast, variables cannot be associated through a linear correlation model, indicating that inhibition zone values cannot predict MIC value. According to the results, disc diffusion assay may not represent an alternative to determine antifungal susceptibility of Malassezia yeast. © 2016 Blackwell Verlag GmbH.

A method for determining the column curve from tests of columns with equal restraints against rotation on the ends

NASA Technical Reports Server (NTRS)

Lundquist, Eugene E; Rossman, Carl A; Houbolt, John C

1943-01-01

The results are presented of a theoretical study for the determination of the column curve from tests of column specimens having ends equally restrained against rotation. The theory of this problem is studied and a curve is shown relating the fixity coefficient c to the critical load, the length of the column, and the magnitude of the elastic restraint. A method of using this curve for the determination of the column curve for columns with pin ends from tests of columns with elastically restrained ends is presented. The results of the method as applied to a series of tests on thin-strip columns of stainless steel are also given.

Meta-Analysis of Rare Binary Adverse Event Data

PubMed Central

Bhaumik, Dulal K.; Amatya, Anup; Normand, Sharon-Lise; Greenhouse, Joel; Kaizar, Eloise; Neelon, Brian; Gibbons, Robert D.

2013-01-01

We examine the use of fixed-effects and random-effects moment-based meta-analytic methods for analysis of binary adverse event data. Special attention is paid to the case of rare adverse events which are commonly encountered in routine practice. We study estimation of model parameters and between-study heterogeneity. In addition, we examine traditional approaches to hypothesis testing of the average treatment effect and detection of the heterogeneity of treatment effect across studies. We derive three new methods, simple (unweighted) average treatment effect estimator, a new heterogeneity estimator, and a parametric bootstrapping test for heterogeneity. We then study the statistical properties of both the traditional and new methods via simulation. We find that in general, moment-based estimators of combined treatment effects and heterogeneity are biased and the degree of bias is proportional to the rarity of the event under study. The new methods eliminate much, but not all of this bias. The various estimators and hypothesis testing methods are then compared and contrasted using an example dataset on treatment of stable coronary artery disease. PMID:23734068

Bivariate random-effects meta-analysis models for diagnostic test accuracy studies using arcsine-based transformations.

PubMed

Negeri, Zelalem F; Shaikh, Mateen; Beyene, Joseph

2018-05-11

Diagnostic or screening tests are widely used in medical fields to classify patients according to their disease status. Several statistical models for meta-analysis of diagnostic test accuracy studies have been developed to synthesize test sensitivity and specificity of a diagnostic test of interest. Because of the correlation between test sensitivity and specificity, modeling the two measures using a bivariate model is recommended. In this paper, we extend the current standard bivariate linear mixed model (LMM) by proposing two variance-stabilizing transformations: the arcsine square root and the Freeman-Tukey double arcsine transformation. We compared the performance of the proposed methods with the standard method through simulations using several performance measures. The simulation results showed that our proposed methods performed better than the standard LMM in terms of bias, root mean square error, and coverage probability in most of the scenarios, even when data were generated assuming the standard LMM. We also illustrated the methods using two real data sets. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Stress Corrosion Testing

NASA Technical Reports Server (NTRS)

1985-01-01

Advanced testing of structural materials was developed by Lewis Research Center and Langley Research Center working with the American Society for Testing and Materials (ASTM). Under contract, Aluminum Company of America (Alcoa) conducted a study for evaluating stress corrosion cracking, and recommended the "breaking load" method which determines fracture strengths as well as measuring environmental degradation. Alcoa and Langley plan to submit the procedure to ASTM as a new testing method.

Methods for Equating Mental Tests.

DTIC Science & Technology

1984-11-01

1983) compared conventional and IRT methods for equating the Test of English as a Foreign Language ( TOEFL ) after chaining. Three conventional and...three IRT equating methods were examined in this study; two sections of TOEFL were each (separately) equated. The IRT methods included the following: (a...group. A separate base form was established for each of the six equating methods. Instead of equating the base-form TOEFL to itself, the last (eighth

Evaluation of 3M molecular detection assay (MDA) Salmonella for the detection of Salmonella in selected foods: collaborative study.

PubMed

Bird, Patrick; Fisher, Kiel; Boyle, Megan; Huffman, Travis; Benzinger, M Joseph; Bedinghaus, Paige; Flannery, Jonathan; Crowley, Erin; Agin, James; Goins, David; Benesh, DeAnn; David, John

2013-01-01

The 3M Molecular Detection Assay (MDA) Salmonella is used with the 3M Molecular Detection System for the detection of Salmonella spp. in food, food-related, and environmental samples after enrichment. The assay utilizes loop-mediated isothermal amplification to rapidly amplify Salmonella target DNA with high specificity and sensitivity, combined with bioluminescence to detect the amplification. The 3M MDA Salmonella method was compared using an unpaired study design in a multilaboratory collaborative study to the U.S. Department of Agriculture/Food Safety and Inspection Service-Microbiology Laboratory Guidebook (USDA/FSIS-MLG 4.05), Isolation and Identification of Salmonella from Meat, Poultry, Pasteurized Egg and Catfish Products for raw ground beef and the U.S. Food and Drug Administration/Bacteriological Analytical Manual (FDA/BAM) Chapter 5 Salmonella reference method for wet dog food following the current AOAC guidelines. A total of 20 laboratories participated. For the 3M MDA Salmonella method, raw ground beef was analyzed using 25 g test portions, and wet dog food was analyzed using 375 g test portions. For the reference methods, 25 g test portions of each matrix were analyzed. Each matrix was artificially contaminated with Salmonella at three inoculation levels: an uninoculated control level (0 CFU/test portion), a low inoculum level (0.2-2 CFU/test portion), and a high inoculum level (2-5 CFU/test portion). In this study, 1512 unpaired replicate samples were analyzed. Statistical analysis was conducted according to the probability of detection (POD). For the low-level raw ground beef test portions, the following dLPOD (difference between the POD of the reference and candidate method) values with 95% confidence intervals were obtained: -0.01 (-0.14, +0.12). For the low-level wet dog food test portions, the following dLPOD with 95% confidence intervals were obtained: -0.04 (-0.16, +0.09). No significant differences were observed in the number of positive samples detected by the 3M MDA Salmonella method versus either the USDA/FSIS-MLG or FDA/BAM methods.

Developing a Non-Language Related Span Test for the Use in Language-Specific and Cross-Language Studies

ERIC Educational Resources Information Center

Shahnazari-Dorcheh, Mohammadtaghi; Roshan, Saeed

2012-01-01

Due to the lack of span test for the use in language-specific and cross-language studies, this study provides L1 and L2 researchers with a reliable language-independent span test (math span test) for the measurement of working memory capacity. It also describes the development, validation, and scoring method of this test. This test included 70…

Portable apparatus with CRT display for nondestructive testing of concrete by the ultrasonic pulse method

NASA Technical Reports Server (NTRS)

Manta, G.; Gurau, Y.; Nica, P.; Facacaru, I.

1974-01-01

The development of methods for the nondestructive study of concrete structures is discussed. The nondestructive test procedure is based on the method of ultrasonic pulse transmission through the material. The measurements indicate that the elastic properties of concrete or other heterogeneous materials are a function of the rate of ultrasonic propagation. Diagrams of the test equipment are provided. Mathematical models are included to support the theoretical aspects.

Case Study: Testing with Case Studies

ERIC Educational Resources Information Center

Herreid, Clyde Freeman

2015-01-01

This column provides original articles on innovations in case study teaching, assessment of the method, as well as case studies with teaching notes. This month's issue discusses using case studies to test for knowledge or lessons learned.

[Selection of risk and diagnosis in diabetic polyneuropathy. Validation of method of new systems].

PubMed

Jurado, Jerónimo; Caula, Jacinto; Pou i Torelló, Josep Maria

2006-06-30

In a previous study we developed a specific algorithm, the polyneuropathy selection method (PSM) with 4 parameters (age, HDL-C, HbA1c, and retinopathy), to select patients at risk of diabetic polyneuropathy (DPN). We also developed a simplified method for DPN diagnosis: outpatient polyneuropathy diagnosis (OPD), with 4 variables (symptoms and 3 objective tests). To confirm the validity of conventional tests for DPN diagnosis; to validate the discriminatory power of the PSM and the diagnostic value of OPD by evaluating their relationship to electrodiagnosis studies and objective clinical neurological assessment; and to evaluate the correlation of DPN and pro-inflammatory status. Cross-sectional, crossed association for PSM validation. Paired samples for OPD validation. Primary care in 3 counties. Random sample of 75 subjects from the type-2 diabetes census for PSM evaluation. Thirty DPN patients and 30 non-DPN patients (from 2 DM2 sub-groups in our earlier study) for OPD evaluation. The gold standard for DPN diagnosis will be studied by means of a clinical neurological study (symptoms, physical examination, and sensitivity tests) and electrodiagnosis studies (sensitivity and motor EMG). Risks of neuropathy, macroangiopathy and pro-inflammatory status (PCR, TNF soluble fraction and total TGF-beta1) will be studied in every subject. Electrodiagnosis studies should confirm the validity of conventional tests for DPN diagnosis. PSM and OPD will be valid methods for selecting patients at risk and diagnosing DPN. There will be a significant relationship between DPN and pro-inflammatory tests.

Meta‐analysis of test accuracy studies using imputation for partial reporting of multiple thresholds

PubMed Central

Deeks, J.J.; Martin, E.C.; Riley, R.D.

2017-01-01

Introduction For tests reporting continuous results, primary studies usually provide test performance at multiple but often different thresholds. This creates missing data when performing a meta‐analysis at each threshold. A standard meta‐analysis (no imputation [NI]) ignores such missing data. A single imputation (SI) approach was recently proposed to recover missing threshold results. Here, we propose a new method that performs multiple imputation of the missing threshold results using discrete combinations (MIDC). Methods The new MIDC method imputes missing threshold results by randomly selecting from the set of all possible discrete combinations which lie between the results for 2 known bounding thresholds. Imputed and observed results are then synthesised at each threshold. This is repeated multiple times, and the multiple pooled results at each threshold are combined using Rubin's rules to give final estimates. We compared the NI, SI, and MIDC approaches via simulation. Results Both imputation methods outperform the NI method in simulations. There was generally little difference in the SI and MIDC methods, but the latter was noticeably better in terms of estimating the between‐study variances and generally gave better coverage, due to slightly larger standard errors of pooled estimates. Given selective reporting of thresholds, the imputation methods also reduced bias in the summary receiver operating characteristic curve. Simulations demonstrate the imputation methods rely on an equal threshold spacing assumption. A real example is presented. Conclusions The SI and, in particular, MIDC methods can be used to examine the impact of missing threshold results in meta‐analysis of test accuracy studies. PMID:29052347

Exploration of Analysis Methods for Diagnostic Imaging Tests: Problems with ROC AUC and Confidence Scores in CT Colonography

PubMed Central

Mallett, Susan; Halligan, Steve; Collins, Gary S.; Altman, Doug G.

2014-01-01

Background Different methods of evaluating diagnostic performance when comparing diagnostic tests may lead to different results. We compared two such approaches, sensitivity and specificity with area under the Receiver Operating Characteristic Curve (ROC AUC) for the evaluation of CT colonography for the detection of polyps, either with or without computer assisted detection. Methods In a multireader multicase study of 10 readers and 107 cases we compared sensitivity and specificity, using radiological reporting of the presence or absence of polyps, to ROC AUC calculated from confidence scores concerning the presence of polyps. Both methods were assessed against a reference standard. Here we focus on five readers, selected to illustrate issues in design and analysis. We compared diagnostic measures within readers, showing that differences in results are due to statistical methods. Results Reader performance varied widely depending on whether sensitivity and specificity or ROC AUC was used. There were problems using confidence scores; in assigning scores to all cases; in use of zero scores when no polyps were identified; the bimodal non-normal distribution of scores; fitting ROC curves due to extrapolation beyond the study data; and the undue influence of a few false positive results. Variation due to use of different ROC methods exceeded differences between test results for ROC AUC. Conclusions The confidence scores recorded in our study violated many assumptions of ROC AUC methods, rendering these methods inappropriate. The problems we identified will apply to other detection studies using confidence scores. We found sensitivity and specificity were a more reliable and clinically appropriate method to compare diagnostic tests. PMID:25353643

A STUDY OF RECOVERING A REED ECOSYSTEM USING POROUS CONCRETE IN THE LAKE BIWA SHORE

NASA Astrophysics Data System (ADS)

Takeda, Naho; Kato, Hayato; Okamoto, Takahisa; Kojima, Takayuki

In this study, reed planting tests were carried out at the Biyo-center, an experiment station on the Lake Biwa shore, in order to evaluate the feasibility of a planting method with porous concrete (PoC method). Reed planting tests with coconut-fiber mats (mat method), which were generally used around Lake Biwa, were simultaneously carried out to compare with the PoC method. The reeds planted by the PoC method grew better than the ones planted by the mat method, and the number of reeds which were washed away by waves was smaller than that planted by the mat method. The result of the observation of reeds planted in the PoC showed plant maturation, and reeds could ta ke root into the PoC without interference with the voids of the PoC. As a result, it was shown that the reed planting tests with the PoC method was simple and effective, so it would become in harmony with the environment around Lake Biwa.

Colorimetric determination of alkaline phosphatase as indicator of mammalian feces in corn meal: collaborative study.

PubMed

Gerber, H

1986-01-01

In the official method for rodent filth in corn meal, filth and corn meal are separated in organic solvents, and particles are identified by the presence of hair and a mucous coating. The solvents are toxic, poor separation yields low recoveries, and fecal characteristics are rarely present on all fragments, especially on small particles. The official AOAC alkaline phosphatase test for mammalian feces, 44.181-44.184, has therefore been adapted to determine the presence of mammalian feces in corn meal. The enzyme cleaves phosphate radicals from a test indicator/substrate, phenolphthalein diphosphate. As free phenolphthalein accumulates, a pink-to-red color develops in the gelled test agar medium. In a collaborative study conducted to compare the proposed method with the official method for corn meal, 44.049, the proposed method yielded 45.5% higher recoveries than the official method. Repeatability and reproducibility for the official method were roughly 1.8 times more variable than for the proposed method. The method has been adopted official first action.

Statistical inference methods for two crossing survival curves: a comparison of methods.

PubMed

Li, Huimin; Han, Dong; Hou, Yawen; Chen, Huilin; Chen, Zheng

2015-01-01

A common problem that is encountered in medical applications is the overall homogeneity of survival distributions when two survival curves cross each other. A survey demonstrated that under this condition, which was an obvious violation of the assumption of proportional hazard rates, the log-rank test was still used in 70% of studies. Several statistical methods have been proposed to solve this problem. However, in many applications, it is difficult to specify the types of survival differences and choose an appropriate method prior to analysis. Thus, we conducted an extensive series of Monte Carlo simulations to investigate the power and type I error rate of these procedures under various patterns of crossing survival curves with different censoring rates and distribution parameters. Our objective was to evaluate the strengths and weaknesses of tests in different situations and for various censoring rates and to recommend an appropriate test that will not fail for a wide range of applications. Simulation studies demonstrated that adaptive Neyman's smooth tests and the two-stage procedure offer higher power and greater stability than other methods when the survival distributions cross at early, middle or late times. Even for proportional hazards, both methods maintain acceptable power compared with the log-rank test. In terms of the type I error rate, Renyi and Cramér-von Mises tests are relatively conservative, whereas the statistics of the Lin-Xu test exhibit apparent inflation as the censoring rate increases. Other tests produce results close to the nominal 0.05 level. In conclusion, adaptive Neyman's smooth tests and the two-stage procedure are found to be the most stable and feasible approaches for a variety of situations and censoring rates. Therefore, they are applicable to a wider spectrum of alternatives compared with other tests.

Statistical Inference Methods for Two Crossing Survival Curves: A Comparison of Methods

PubMed Central

Li, Huimin; Han, Dong; Hou, Yawen; Chen, Huilin; Chen, Zheng

2015-01-01

A common problem that is encountered in medical applications is the overall homogeneity of survival distributions when two survival curves cross each other. A survey demonstrated that under this condition, which was an obvious violation of the assumption of proportional hazard rates, the log-rank test was still used in 70% of studies. Several statistical methods have been proposed to solve this problem. However, in many applications, it is difficult to specify the types of survival differences and choose an appropriate method prior to analysis. Thus, we conducted an extensive series of Monte Carlo simulations to investigate the power and type I error rate of these procedures under various patterns of crossing survival curves with different censoring rates and distribution parameters. Our objective was to evaluate the strengths and weaknesses of tests in different situations and for various censoring rates and to recommend an appropriate test that will not fail for a wide range of applications. Simulation studies demonstrated that adaptive Neyman’s smooth tests and the two-stage procedure offer higher power and greater stability than other methods when the survival distributions cross at early, middle or late times. Even for proportional hazards, both methods maintain acceptable power compared with the log-rank test. In terms of the type I error rate, Renyi and Cramér—von Mises tests are relatively conservative, whereas the statistics of the Lin-Xu test exhibit apparent inflation as the censoring rate increases. Other tests produce results close to the nominal 0.05 level. In conclusion, adaptive Neyman’s smooth tests and the two-stage procedure are found to be the most stable and feasible approaches for a variety of situations and censoring rates. Therefore, they are applicable to a wider spectrum of alternatives compared with other tests. PMID:25615624

Sensitivity and specificity of normality tests and consequences on reference interval accuracy at small sample size: a computer-simulation study.

PubMed

Le Boedec, Kevin

2016-12-01

According to international guidelines, parametric methods must be chosen for RI construction when the sample size is small and the distribution is Gaussian. However, normality tests may not be accurate at small sample size. The purpose of the study was to evaluate normality test performance to properly identify samples extracted from a Gaussian population at small sample sizes, and assess the consequences on RI accuracy of applying parametric methods to samples that falsely identified the parent population as Gaussian. Samples of n = 60 and n = 30 values were randomly selected 100 times from simulated Gaussian, lognormal, and asymmetric populations of 10,000 values. The sensitivity and specificity of 4 normality tests were compared. Reference intervals were calculated using 6 different statistical methods from samples that falsely identified the parent population as Gaussian, and their accuracy was compared. Shapiro-Wilk and D'Agostino-Pearson tests were the best performing normality tests. However, their specificity was poor at sample size n = 30 (specificity for P < .05: .51 and .50, respectively). The best significance levels identified when n = 30 were 0.19 for Shapiro-Wilk test and 0.18 for D'Agostino-Pearson test. Using parametric methods on samples extracted from a lognormal population but falsely identified as Gaussian led to clinically relevant inaccuracies. At small sample size, normality tests may lead to erroneous use of parametric methods to build RI. Using nonparametric methods (or alternatively Box-Cox transformation) on all samples regardless of their distribution or adjusting, the significance level of normality tests depending on sample size would limit the risk of constructing inaccurate RI. © 2016 American Society for Veterinary Clinical Pathology.

Effect of Direct Teaching Method on the Academic Achievement of High and Low Achievers in the Subject of English at the Secondary Level

ERIC Educational Resources Information Center

Hussain, Ishtiaq; Hamdani, Syed Nisar Hussain; Quraishi, Uzma; Zeeshan, Muhammad

2010-01-01

The major objective of the study was to determine the role of the direct teaching method in the academic achievement of students in English at the secondary level. To achieve the said objective, the Solomon Four-Design pre-test/post-test equivalent group design was considered to be the most useful design for this study. The pre-test was used to…

Interlaboratory Study of Quality Control Isolates for a Broth Microdilution Method (Modified CLSI M38-A) for Testing Susceptibilities of Dermatophytes to Antifungals▿

PubMed Central

Ghannoum, M. A.; Arthington-Skaggs, B.; Chaturvedi, V.; Espinel-Ingroff, A.; Pfaller, M. A.; Rennie, R.; Rinaldi, M. G.; Walsh, T. J.

2006-01-01

The Clinical and Laboratory Standards Institute (CLSI; formerly National Committee for Clinical Laboratory Standards, or NCCLS) M38-A standard for the susceptibility testing of filamentous fungi does not specifically address the testing of dermatophytes. In 2003, a multicenter study investigated the reproducibility of the microdilution method developed at the Center for Medical Mycology, Cleveland, Ohio, for testing the susceptibility of dermatophytes. Data from that study supported the introduction of this method for testing dermatophytes in the future version of the CLSI M38-A standard. In order for the method to be accepted by CLSI, appropriate quality control isolates needed to be identified. To that end, an interlaboratory study, involving the original six laboratories plus two additional sites, was conducted to evaluate potential candidates for quality control isolates. These candidate strains included five Trichophyton rubrum strains known to have elevated MICs to terbinafine and five Trichophyton mentagrophytes strains. Antifungal agents tested included ciclopirox, fluconazole, griseofulvin, itraconazole, posaconazole, terbinafine, and voriconazole. Based on the data generated, two quality control isolates, one T. rubrum isolate and one T. mentagrophytes isolate, were identified and submitted to the American Type Culture Collection (ATCC) for inclusion as reference strains. Ranges encompassing 95.2 to 97.9% of all data points for all seven drugs were established. PMID:17050812

Local tolerance testing under REACH: Accepted non-animal methods are not on equal footing with animal tests.

PubMed

Sauer, Ursula G; Hill, Erin H; Curren, Rodger D; Raabe, Hans A; Kolle, Susanne N; Teubner, Wera; Mehling, Annette; Landsiedel, Robert

2016-07-01

In general, no single non-animal method can cover the complexity of any given animal test. Therefore, fixed sets of in vitro (and in chemico) methods have been combined into testing strategies for skin and eye irritation and skin sensitisation testing, with pre-defined prediction models for substance classification. Many of these methods have been adopted as OECD test guidelines. Various testing strategies have been successfully validated in extensive in-house and inter-laboratory studies, but they have not yet received formal acceptance for substance classification. Therefore, under the European REACH Regulation, data from testing strategies can, in general, only be used in so-called weight-of-evidence approaches. While animal testing data generated under the specific REACH information requirements are per se sufficient, the sufficiency of weight-of-evidence approaches can be questioned under the REACH system, and further animal testing can be required. This constitutes an imbalance between the regulatory acceptance of data from approved non-animal methods and animal tests that is not justified on scientific grounds. To ensure that testing strategies for local tolerance testing truly serve to replace animal testing for the REACH registration 2018 deadline (when the majority of existing chemicals have to be registered), clarity on their regulatory acceptance as complete replacements is urgently required. 2016 FRAME.

CTEPP STANDARD OPERATING PROCEDURE FOR PACKING AND SHIPPING STUDY SAMPLES (SOP-3.11)

EPA Science Inventory

This SOP describes the methods for packing and shipping study samples. These methods are for packing and shipping biological and environmental samples. The methods have been tested and used in the previous pilot studies.

The Effects of Web-Based Interactive Virtual Tours on the Development of Prospective Mathematics Teachers' Spatial Skills

ERIC Educational Resources Information Center

Kurtulus, Aytac

2013-01-01

The aim of this study was to investigate the effects of web-based interactive virtual tours on the development of prospective mathematics teachers' spatial skills. The study was designed based on experimental method. The "one-group pre-test post-test design" of this method was taken as the research model. The study was conducted with 3rd year…

Gene toxicity studies on titanium dioxide and zinc oxide nanomaterials used for UV-protection in cosmetic formulations.

PubMed

Landsiedel, Robert; Ma-Hock, Lan; Van Ravenzwaay, Ben; Schulz, Markus; Wiench, Karin; Champ, Samantha; Schulte, Stefan; Wohlleben, Wendel; Oesch, Franz

2010-12-01

Titanium dioxide and zinc oxide nanomaterials, used as UV protecting agents in sunscreens, were investigated for their potential genotoxicity in in vitro and in vivo test systems. Since standard OECD test methods are designed for soluble materials and genotoxicity testing for nanomaterials is still under revision, a battery of standard tests was used, covering different endpoints. Additionally, a procedure to disperse the nanomaterials in the test media and careful characterization of the dispersed test item was added to the testing methods. No genotoxicity was observed in vitro (Ames' Salmonella gene mutation test and V79 micronucleus chromosome mutation test) or in vivo (mouse bone marrow micronucleus test and Comet DNA damage assay in lung cells from rats exposed by inhalation). These results add to the still limited data base on genotoxicity test results with nanomaterials and provide congruent results of a battery of standard OECD test methods applied to nanomaterials.

Warm-Up Effect in Panelist-Articulated-2-Alternative Forced Choice Test.

PubMed

Bloom, David J; Baik, Hwa-Young; Lee, Soo-Yeun

2018-01-01

Panelist performance in discrimination tests has been shown to increase when warm-up samples are provided prior to the actual test. Samples are used prior to the actual test for the attribute articulation process of a panelist-articulated-2-alternative forced choice (PA-2-AFC) procedure; however, it is yet unknown if the pretest articulation phase adds to the power of this testing method as with the warm-up. The goal of the study was to determine if a "warm-up" effect was displayed in the PA-2-AFC test resulting in greater power compared to the researcher-designated-2-AFC (RD-2-AFC) test. A RD-2-AFC test, with and without warm-up samples, and a PA-2-AFC test were performed by 61 panelists. A reduced calorie, citrus-flavored, and carbonated beverage was used in the tests. During RD-2-AFC testing, panelists were asked to identify which sample was more sour. For PA-2-AFC testing, panelists individually articulated the nature and direction of the difference between the 2 samples through a pretesting articulation procedure. The articulated difference was, then, used in standard 2-AFC test procedure. A warm-up effect was observed when comparing the standard RD-2-AFC with and without warm-up samples. The addition of warm up samples significantly increased the power of the test, in addition, the PA-2-AFC method had lower power than the RD-2-AFC method. The increase in power with the addition of warm-up samples for the RD-2-AFC procedure supports literature findings on the benefit of providing warm-up samples. No warm-up effect can be attributed to the PA-2-AFC method evidenced by the overall low power observed, which may be attributed to sample complexity. Selecting a specified discrimination testing method is advantageous and can reduce costs of sensory testing, but has been considered unpractical when samples may differ in unknown ways. This research explores the use of panelist derived terms to circumvent the need for researchers to identify these differences and compares the results to using research designated terms in discrimination testing. Results from this study can be utilized in creating ways to incorporate more powerful methods into sensory discrimination testing plans and provides researchers with a means for selecting terms for use in specified discrimination testing methods. © 2017 Institute of Food Technologists®.

Specific Yields Estimated from Gravity Change during Pumping Test

NASA Astrophysics Data System (ADS)

Chen, K. H.; Hwang, C.; Chang, L. C.

2017-12-01

Specific yield (Sy) is the most important parameter to describe available groundwater capacity in an unconfined aquifer. When estimating Sy by a field pumping test, aquifer heterogeneity and well performers will cause a large uncertainty. In this study, we use a gravity-based method to estimate Sy. At the time of pumping test, amounts of mass (groundwater) are forced to be taken out. If drawdown corn is big and close enough to high precision gravimeter, the gravity change can be detected. The gravity-based method use gravity observations that are independent from traditional flow computation. Only the drawdown corn should be modeled with observed head and hydrogeology data. The gravity method can be used in most groundwater field tests, such as locally pumping/injection tests initiated by active man-made or annual variations due to natural sources. We apply our gravity method at few sites in Taiwan situated over different unconfined aquifer. Here pumping tests for Sy determinations were also carried out. We will discuss why the gravity method produces different results from traditional pumping test, field designs and limitations of the gravity method.

Clinical experimental stress studies: methods and assessment.

PubMed

Bali, Anjana; Jaggi, Amteshwar Singh

2015-01-01

Stress is a state of threatened homeostasis during which a variety of adaptive processes are activated to produce physiological and behavioral changes. Stress induction methods are pivotal for understanding these physiological or pathophysiological changes in the body in response to stress. Furthermore, these methods are also important for the development of novel pharmacological agents for stress management. The well-described methods to induce stress in humans include the cold pressor test, Trier Social Stress Test, Montreal Imaging Stress Task, Maastricht Acute Stress Test, CO2 challenge test, Stroop test, Paced Auditory Serial Addition Task, noise stress, and Mannheim Multicomponent Stress Test. Stress assessment in humans is done by measuring biochemical markers such as cortisol, cortisol awakening response, dexamethasone suppression test, salivary α-amylase, plasma/urinary norepinephrine, norepinephrine spillover rate, and interleukins. Physiological and behavioral changes such as galvanic skin response, heart rate variability, pupil size, and muscle and/or skin sympathetic nerve activity (microneurography) and cardiovascular parameters such as heart rate, blood pressure, and self-reported anxiety are also monitored to assess stress response. This present review describes these commonly employed methods to induce stress in humans along with stress assessment methods.

Estimation of the Operating Characteristics when the Test Information of the Old Test is not Constant II: Simple Sum Procedure of the Conditional P.D.F. Approach/Normal Approach Method Using Three Subtests of the Old Test. Research Report 80-4.

ERIC Educational Resources Information Center

Samejima, Fumiko

The rationale behind the method of estimating the operating characteristics of discrete item responses when the test information of the Old Test is not constant was presented previously. In the present study, two subtests of the Old Test, i.e. Subtests 1, and 2, each of which has a different non-constant test information function, are used in…

Working with Sparse Data in Rated Language Tests: Generalizability Theory Applications

ERIC Educational Resources Information Center

Lin, Chih-Kai

2017-01-01

Sparse-rated data are common in operational performance-based language tests, as an inevitable result of assigning examinee responses to a fraction of available raters. The current study investigates the precision of two generalizability-theory methods (i.e., the rating method and the subdividing method) specifically designed to accommodate the…

Testing for association with multiple traits in generalized estimation equations, with application to neuroimaging data.

PubMed

Zhang, Yiwei; Xu, Zhiyuan; Shen, Xiaotong; Pan, Wei

2014-08-01

There is an increasing need to develop and apply powerful statistical tests to detect multiple traits-single locus associations, as arising from neuroimaging genetics and other studies. For example, in the Alzheimer's Disease Neuroimaging Initiative (ADNI), in addition to genome-wide single nucleotide polymorphisms (SNPs), thousands of neuroimaging and neuropsychological phenotypes as intermediate phenotypes for Alzheimer's disease, have been collected. Although some classic methods like MANOVA and newly proposed methods may be applied, they have their own limitations. For example, MANOVA cannot be applied to binary and other discrete traits. In addition, the relationships among these methods are not well understood. Importantly, since these tests are not data adaptive, depending on the unknown association patterns among multiple traits and between multiple traits and a locus, these tests may or may not be powerful. In this paper we propose a class of data-adaptive weights and the corresponding weighted tests in the general framework of generalized estimation equations (GEE). A highly adaptive test is proposed to select the most powerful one from this class of the weighted tests so that it can maintain high power across a wide range of situations. Our proposed tests are applicable to various types of traits with or without covariates. Importantly, we also analytically show relationships among some existing and our proposed tests, indicating that many existing tests are special cases of our proposed tests. Extensive simulation studies were conducted to compare and contrast the power properties of various existing and our new methods. Finally, we applied the methods to an ADNI dataset to illustrate the performance of the methods. We conclude with the recommendation for the use of the GEE-based Score test and our proposed adaptive test for their high and complementary performance. Copyright © 2014 Elsevier Inc. All rights reserved.

Development of test methods for scale model simulation of aerial applications in the NASA Langley Vortex Research Facility. [agricultural aircraft

NASA Technical Reports Server (NTRS)

Jordan, F. L., Jr.

1980-01-01

As part of basic research to improve aerial applications technology, methods were developed at the Langley Vortex Research Facility to simulate and measure deposition patterns of aerially-applied sprays and granular materials by means of tests with small-scale models of agricultural aircraft and dynamically-scaled test particles. Interactions between the aircraft wake and the dispersed particles are being studied with the objective of modifying wake characteristics and dispersal techniques to increase swath width, improve deposition pattern uniformity, and minimize drift. The particle scaling analysis, test methods for particle dispersal from the model aircraft, visualization of particle trajectories, and measurement and computer analysis of test deposition patterns are described. An experimental validation of the scaling analysis and test results that indicate improved control of chemical drift by use of winglets are presented to demonstrate test methods.

The history and development of FETAX (ASTM standard guide, E-1439 on conducting the frog embryo teratogenesis Assay-Xenopus)

USGS Publications Warehouse

Dumont, J.N.; Bantle, J.A.; Linder, G.; ,

2003-01-01

The energy crisis of the 1970's and 1980's prompted the search for alternative sources of fuel. With development of alternate sources of energy, concerns for biological resources potentially adversely impacted by these alternative technologies also heightened. For example, few biological tests were available at the time to study toxic effects of effluents on surface waters likely to serve as receiving streams for energy-production facilities; hence, we began to use Xenopus laevis embryos as test organisms to examine potential toxic effects associated with these effluents upon entering aquatic systems. As studies focused on potential adverse effects on aquatic systems continued, a test procedure was developed that led to the initial standardization of FETAX. Other .than a limited number of aquatic toxicity tests that used fathead minnows and cold-water fishes such as rainbow trout, X. laevis represented the only other aquatic vertebrate test system readily available to evaluate complex effluents. With numerous laboratories collaborating, the test with X. laevis was refined, improved, and developed as ASTM E-1439, Standard Guide for the Conducting Frog Embryo Teratogenesis Assay-Xenopus (FETAX). Collabrative work in the 1990s yielded procedural enhancements, for example, development of standard test solutions and exposure methods to handle volatile organics and hydrophobic compounds. As part of the ASTM process, a collaborative interlaboratory study was performed to determine the repeatability and reliability of FETAX. Parallel to these efforts, methods were also developed to test sediments and soils, and in situ test methods were developed to address "lab-to-field extrapolation errors" that could influence the method's use in ecological risk assessments. Additionally, a metabolic activation system composed of rat liver microsomes was developed which made FETAX more relevant to mammalian studies.

An Adaptive Association Test for Multiple Phenotypes with GWAS Summary Statistics.

PubMed

Kim, Junghi; Bai, Yun; Pan, Wei

2015-12-01

We study the problem of testing for single marker-multiple phenotype associations based on genome-wide association study (GWAS) summary statistics without access to individual-level genotype and phenotype data. For most published GWASs, because obtaining summary data is substantially easier than accessing individual-level phenotype and genotype data, while often multiple correlated traits have been collected, the problem studied here has become increasingly important. We propose a powerful adaptive test and compare its performance with some existing tests. We illustrate its applications to analyses of a meta-analyzed GWAS dataset with three blood lipid traits and another with sex-stratified anthropometric traits, and further demonstrate its potential power gain over some existing methods through realistic simulation studies. We start from the situation with only one set of (possibly meta-analyzed) genome-wide summary statistics, then extend the method to meta-analysis of multiple sets of genome-wide summary statistics, each from one GWAS. We expect the proposed test to be useful in practice as more powerful than or complementary to existing methods. © 2015 WILEY PERIODICALS, INC.

[Study on seed testing for Salvia miltiorrhiza].

PubMed

Dan, Hong-mei; Qi, Jian-jun; Zhou, Li-li; Li, Xian-en

2008-09-01

To establish a seed testing methods for Salvia miltiorrhiza. Referring to the International Seed Testing Rules made by ISTA and the Seed Testing for Crops (GB/T3543. 1-1995) issued by China. The seeds are selected by winnowing; the seed purity is about 50%-60%; 100 grain weight is used to determine the quality of the seed; the seed moisture content is determined by air drying, the drying hour is 3 h. Seed viability is tested by TFC method.

Acceptability of Using Electronic Vending Machines to Deliver Oral Rapid HIV Self-Testing Kits: A Qualitative Study

PubMed Central

Young, Sean D.; Daniels, Joseph; Chiu, ChingChe J.; Bolan, Robert K.; Flynn, Risa P.; Kwok, Justin; Klausner, Jeffrey D.

2014-01-01

Introduction Rates of unrecognized HIV infection are significantly higher among Latino and Black men who have sex with men (MSM). Policy makers have proposed that HIV self-testing kits and new methods for delivering self-testing could improve testing uptake among minority MSM. This study sought to conduct qualitative assessments with MSM of color to determine the acceptability of using electronic vending machines to dispense HIV self-testing kits. Materials and Methods African American and Latino MSM were recruited using a participant pool from an existing HIV prevention trial on Facebook. If participants expressed interest in using a vending machine to receive an HIV self-testing kit, they were emailed a 4-digit personal identification number (PIN) code to retrieve the test from the machine. We followed up with those who had tested to assess their willingness to participate in an interview about their experience. Results Twelve kits were dispensed and 8 interviews were conducted. In general, participants expressed that the vending machine was an acceptable HIV test delivery method due to its novelty and convenience. Discussion Acceptability of this delivery model for HIV testing kits was closely associated with three main factors: credibility, confidentiality, and convenience. Future research is needed to address issues, such as user-induced errors and costs, before scaling up the dispensing method. PMID:25076208

The Effect of Montessori Method on Cognitive Tempo of Kindergarten Children

ERIC Educational Resources Information Center

Kayili, Gökhan

2018-01-01

This study was undertaken to discover the effect of the Montessori Method on the cognitive tempo of 4-5-year-old children. Using an experimental pre-test-post-test paired control group design, the study sample included 60 children attending Ihsan Dogramaci Applied Nursery School (affiliated to Selcuk University, Department of Health Sciences) in…

Secondary Schools Principals and Their Job Satisfaction: A Test of Process Theories

ERIC Educational Resources Information Center

Maforah, Tsholofelo Paulinah

2015-01-01

The study aims to test the validity of process theories on the job satisfaction of previously disadvantaged Secondary School principals in the North West province. A mixed-method approach consisting of both quantitative and qualitative methods was used for the study. A questionnaire was administered during the quantitative phase with a sample that…

Exploring and Testing the Predictors of New Faculty Success: A Mixed Methods Study

ERIC Educational Resources Information Center

Stupnisky, R. H.; Weaver-Hightower, M. B.; Kartoshkina, Y.

2015-01-01

The purpose of this mixed methods study was to investigate and test the factors contributing to new faculty members' success. In the first phase, qualitative analysis of focus groups revealed four prominent themes affecting new faculty members: expectations, collegiality, balance, and location. In the second phase, new faculty members completed an…

A Comparison of Methods to Test for Mediation in Multisite Experiments

ERIC Educational Resources Information Center

Pituch, Keenan A.; Whittaker, Tiffany A.; Stapleton, Laura M.

2005-01-01

A Monte Carlo study extended the research of MacKinnon, Lockwood, Hoffman, West, and Sheets (2002) for single-level designs by examining the statistical performance of four methods to test for mediation in a multilevel experimental design. The design studied was a two-group experiment that was replicated across several sites, included a single…

Staff Study on Cost and Training Effectiveness of Proposed Training Systems. TAEG Report 1.

ERIC Educational Resources Information Center

Naval Training Equipment Center, Orlando, FL. Training Analysis and Evaluation Group.

A study began the development and initial testing of a method for predicting cost and training effectiveness of proposed training programs. A prototype Training Effectiveness and Cost Effectiveness Prediction (TECEP) model was developed and tested. The model was a method for optimization of training media allocation on the basis of fixed training…

Studies of the Lateral-Directional Flying Qualities of a Tandem Helicopter in Forward Flight

NASA Technical Reports Server (NTRS)

Amer, Kenneth B; Tapscott, Robert J

1954-01-01

An investigation of the lateral-directional flying qualities of a tandem-rotor helicopter in forward flight was undertaken to determine desirable goals for helicopter lateral-directional flying qualities and possible methods of achieving these goals in the tandem-rotor helicopter. Comparison between directional stability as measured in flight and rotor-off model tests in a wind tunnel shows qualitative agreement and, hence, indicates such wind-tunnel test, despite the absence of the rotors, to be one effective method of studying means of improving the directional stability of the tandem helicopter. Flight-test measurements of turns and oscillations, in conjunction with analytical studies, suggest possible practical methods of achieving the goals of satisfactory turn and oscillatory characteristics in the tandem helicopter.

Comparison of attrition test methods: ASTM standard fluidized bed vs jet cup

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

Zhao, R.; Goodwin, J.G. Jr.; Jothimurugesan, K.

2000-05-01

Attrition resistance is one of the key design parameters for catalysts used in fluidized-bed and slurry phase types of reactors. The ASTM fluidized-bed test has been one of the most commonly used attrition resistance evaluation methods; however, it requires the use of 50 g samples--a large amount for catalyst development studies. Recently a test using the jet cup requiring only 5 g samples has been proposed. In the present study, two series of spray-dried iron catalysts were evaluated using both the ASTM fluidized-bed test and a test based on the jet cup to determine this comparability. It is shown thatmore » the two tests give comparable results. This paper, by reporting a comparison of the jet-cup test with the ASTM standard, provides a basis for utilizing the more efficient jet cup with confidence in catalyst attrition studies.« less

Effectiveness of Video Demonstration over Conventional Methods in Teaching Osteology in Anatomy.

PubMed

Viswasom, Angela A; Jobby, Abraham

2017-02-01

Technology and its applications are the most happening things in the world. So, is it in the field of medical education. This study was an evaluation of whether the conventional methods can compete with the test of technology. A comparative study of traditional method of teaching osteology in human anatomy with an innovative visual aided method. The study was conducted on 94 students admitted to MBBS 2014 to 2015 batch of Travancore Medical College. The students were divided into two academically validated groups. They were taught using conventional and video demonstrational techniques in a systematic manner. Post evaluation tests were conducted. Analysis of the mark pattern revealed that the group taught using traditional method scored better when compared to the visual aided method. Feedback analysis showed that, the students were able to identify bony features better with clear visualisation and three dimensional view when taught using the video demonstration method. The students identified visual aided method as the more interesting one for learning which helped them in applying the knowledge gained. In most of the questions asked, the two methods of teaching were found to be comparable on the same scale. As the study ends, we discover that, no new technique can be substituted for time tested techniques of teaching and learning. The ideal method would be incorporating newer multimedia techniques into traditional classes.

Diagnostic Performance of a Molecular Test versus Clinician Assessment of Vaginitis.

PubMed

Schwebke, Jane R; Gaydos, Charlotte A; Nyirjesy, Paul; Paradis, Sonia; Kodsi, Salma; Cooper, Charles K

2018-06-01

Vaginitis is a common complaint, diagnosed either empirically or using Amsel's criteria and wet mount microscopy. This study sought to determine characteristics of an investigational test (a molecular test for vaginitis), compared to reference, for detection of bacterial vaginosis, Candida spp., and Trichomonas vaginalis Vaginal specimens from a cross-sectional study were obtained from 1,740 women (≥18 years old), with vaginitis symptoms, during routine clinic visits (across 10 sites in the United States). Specimens were analyzed using a commercial PCR/fluorogenic probe-based investigational test that detects bacterial vaginosis, Candida spp., and Trichomonas vaginalis Clinician diagnosis and in-clinic testing (Amsel's test, potassium hydroxide preparation, and wet mount) were also employed to detect the three vaginitis causes. All testing methods were compared to the respective reference methods (Nugent Gram stain for bacterial vaginosis, detection of the Candida gene its2 , and Trichomonas vaginalis culture). The investigational test, clinician diagnosis, and in-clinic testing were compared to reference methods for bacterial vaginosis, Candida spp., and Trichomonas vaginalis The investigational test resulted in significantly higher sensitivity and negative predictive value than clinician diagnosis or in-clinic testing. In addition, the investigational test showed a statistically higher overall percent agreement with each of the three reference methods than did clinician diagnosis or in-clinic testing. The investigational test showed significantly higher sensitivity for detecting vaginitis, involving more than one cause, than did clinician diagnosis. Taken together, these results suggest that a molecular investigational test can facilitate accurate detection of vaginitis. Copyright © 2018 Schwebke et al.

Evaluation of 3 dental unit waterline contamination testing methods

PubMed Central

Porteous, Nuala; Sun, Yuyu; Schoolfield, John

2015-01-01

Previous studies have found inconsistent results from testing methods used to measure heterotrophic plate count (HPC) bacteria in dental unit waterline (DUWL) samples. This study used 63 samples to compare the results obtained from an in-office chairside method and 2 currently used commercial laboratory HPC methods (Standard Methods 9215C and 9215E). The results suggest that the Standard Method 9215E is not suitable for application to DUWL quality monitoring, due to the detection of limited numbers of heterotrophic organisms at the required 35°C incubation temperature. The results also confirm that while the in-office chairside method is useful for DUWL quality monitoring, the Standard Method 9215C provided the most accurate results. PMID:25574718

Evaluation performance of diagnostic methods of intestinal parasitosis in school age children in Ethiopia.

PubMed

Yimer, Mulat; Hailu, Tadesse; Mulu, Wondemagegn; Abera, Bayeh

2015-12-26

Although the sensitivity of Wet mount technique is questionable, it is the major diagnostic technique for routine diagnosis of intestinal parasitosis in Ethiopia. Therefore, the aim of this study was the evaluation performance of diagnostic methods of intestinal parasitosis in school age children in Ethiopia. A cross sectional study was conducted from May to June 2013. Single stool sample was processed for direct, Formol ether concentration (FEC) and Kato Katz methods. The sensitivity and negative predictive value (NPV) of diagnostic tests were calculated in terms of the "Gold" standard method (the combined result of the three methods altogether). A total of 422 school age children were participated in this study. The prevalence of intestinal parasites was high (74.6%) with Kato Katz technique. The sensitivity of Wet mount, FEC and Kato Katz tests against the Gold standard test was 48.9, 63.1 and 93.7%, respectively. Kato Katz technique revealed a better NPV 80.4 (80.1-80.6) as compared to the Wet mount (33.7%) and FEC techniques (41.3%). In this study, the Kato Katz technique outperformed the other two methods but the true values for sensitivity, specificity and diagnostic values are not known. Moreover, it is labor intensive and not easily accessible. Hence, it is preferable to use FEC technique to complement the Wet mount test.

Hybrid Residual Flexibility/Mass-Additive Method for Structural Dynamic Testing

NASA Technical Reports Server (NTRS)

Tinker, M. L.

2003-01-01

A large fixture was designed and constructed for modal vibration testing of International Space Station elements. This fixed-base test fixture, which weighs thousands of pounds and is anchored to a massive concrete floor, initially utilized spherical bearings and pendulum mechanisms to simulate Shuttle orbiter boundary constraints for launch of the hardware. Many difficulties were encountered during a checkout test of the common module prototype structure, mainly due to undesirable friction and excessive clearances in the test-article-to-fixture interface bearings. Measured mode shapes and frequencies were not representative of orbiter-constrained modes due to the friction and clearance effects in the bearings. As a result, a major redesign effort for the interface mechanisms was undertaken. The total cost of the fixture design, construction and checkout, and redesign was over $2 million. Because of the problems experienced with fixed-base testing, alternative free-suspension methods were studied, including the residual flexibility and mass-additive approaches. Free-suspension structural dynamics test methods utilize soft elastic bungee cords and overhead frame suspension systems that are less complex and much less expensive than fixed-base systems. The cost of free-suspension fixturing is on the order of tens of thousands of dollars as opposed to millions, for large fixed-base fixturing. In addition, free-suspension test configurations are portable, allowing modal tests to be done at sites without modal test facilities. For example, a mass-additive modal test of the ASTRO-1 Shuttle payload was done at the Kennedy Space Center launch site. In this Technical Memorandum, the mass-additive and residual flexibility test methods are described in detail. A discussion of a hybrid approach that combines the best characteristics of each method follows and is the focus of the study.

Evaluation of FEM engineering parameters from insitu tests

DOT National Transportation Integrated Search

2001-12-01

The study looked critically at insitu test methods (SPT, CPT, DMT, and PMT) as a means for developing finite element constitutive model input parameters. The first phase of the study examined insitu test derived parameters with laboratory triaxial te...

The relationship between ground reaction force in sit-to-stand movement and lower extremity function in community-dwelling Japanese older adults using long-term care insurance services

PubMed Central

Shen, Shaoshuai; Abe, Takumi; Tsuji, Taishi; Fujii, Keisuke; Ma, Jingyu; Okura, Tomohiro

2017-01-01

[Purpose] The purpose of this study was to investigate which of the four chair-rising methods has low-load and the highest success rate, and whether the GRF parameters in that method are useful for measuring lower extremity function among physically frail Japanese older adults. [Subjects and Methods] Fifty-two individuals participated in this study. The participants voluntarily attempted four types of Sit-to-stand test (one variation without and three variations with the use of their arms). The following parameters were measured: peak reaction force (F/w), two force development rate parameters (RFD1.25/w, RFD8.75/w) and two time-related parameters (T1, T2). Three additional commonly employed clinical tests (One-leg balance with eyes open, Timed up and go and 5-meter walk test) were also conducted. [Results] “Hands on a chair” chair-rising method produced the highest success rate among the four methods. All parameters were highly reliable between testing occasions. T2 showed strongly significant associations with Timed up and go and 5-meter walk test in males. RFD8.75/w showed significant associations with Timed up and go and 5-meter walk test in females. [Conclusion] Ground reaction force parameters in the Sit-to-stand test are a reliable and useful method for assessment of lower extremity function in physically frail Japanese older adults. PMID:28931988

The study of stiffness modulus values for AC-WC pavement

NASA Astrophysics Data System (ADS)

Lubis, AS; Muis, Z. A.; Iskandar, T. D.

2018-02-01

One of the parameters of the asphalt mixture in order for the strength and durability to be achieved as required is the stress-and-strain showing the stiffness of a material. Stiffness modulus is a very necessary factor that will affect the performance of asphalt pavements. If the stiffness modulus value decreases there will be a cause of aging asphalt pavement crack easily when receiving a heavy load. The high stiffness modulus asphalt concrete causes more stiff and resistant to bending. The stiffness modulus value of an asphalt mixture material can be obtained from the theoretical (indirect methods) and laboratory test results (direct methods). For the indirect methods used Brown & Brunton method, and Shell Bitumen method; while for the direct methods used the UMATTA tool. This study aims to determine stiffness modulus values for AC-WC pavement. The tests were conducted in laboratory that used 3 methods, i.e. Brown & Brunton Method, Shell Bitumen Method and Marshall Test as a substitute tool for the UMATTA tool. Hotmix asphalt made from type AC-WC with pen 60/70 using a mixture of optimum bitumen content was 5.84% with a standard temperature variation was 60°C and several variations of temperature that were 30, 40, 50, 70 and 80°C. The stiffness modulus value results obtained from Brown & Brunton Method, Shell Bitumen Method and Marshall Test which were 1374,93 Mpa, 235,45 Mpa dan 254,96 Mpa. The stiffness modulus value decreases with increasing temperature of the concrete asphalt. The stiffness modulus value from the Bitumen Shell method and the Marshall Test has a relatively similar value.The stiffness modulus value from the Brown & Brunton method is greater than the Bitumen Shell method and the Marshall Test, but can not measure the stiffness modulus value at temperature above 80°C.

Comparative Study of Impedance Eduction Methods. Part 1; DLR Tests and Methodology

NASA Technical Reports Server (NTRS)

Busse-Gerstengarbe, Stefan; Bake, Friedrich; Enghardt, Lars; Jones, Michael G.

2013-01-01

The absorption efficiency of acoustic liners used in aircraft engines is characterized by the acoustic impedance. World wide, many grazing ow test rigs and eduction methods are available that provide values for that impedance. However, a direct comparison and assessment of the data of the di erent rigs and methods is often not possible because test objects and test conditions are quite di erent. Only a few papers provide a direct comparison. Therefore, this paper together with a companion paper, present data measured with a reference test object under similar conditions in the DLR and NASA grazing ow test rigs. Additionally, by applying the in-house methods Liner Impedance Non-Uniform ow Solving algorithm (LINUS, DLR) and Convected Helmhholtz Equation approach (CHE, NASA) on the data sets, similarities and differences due to underlying theory are identi ed and discussed.

A hybrid method in combining treatment effects from matched and unmatched studies.

PubMed

Byun, Jinyoung; Lai, Dejian; Luo, Sheng; Risser, Jan; Tung, Betty; Hardy, Robert J

2013-12-10

The most common data structures in the biomedical studies have been matched or unmatched designs. Data structures resulting from a hybrid of the two may create challenges for statistical inferences. The question may arise whether to use parametric or nonparametric methods on the hybrid data structure. The Early Treatment for Retinopathy of Prematurity study was a multicenter clinical trial sponsored by the National Eye Institute. The design produced data requiring a statistical method of a hybrid nature. An infant in this multicenter randomized clinical trial had high-risk prethreshold retinopathy of prematurity that was eligible for treatment in one or both eyes at entry into the trial. During follow-up, recognition visual acuity was accessed for both eyes. Data from both eyes (matched) and from only one eye (unmatched) were eligible to be used in the trial. The new hybrid nonparametric method is a meta-analysis based on combining the Hodges-Lehmann estimates of treatment effects from the Wilcoxon signed rank and rank sum tests. To compare the new method, we used the classic meta-analysis with the t-test method to combine estimates of treatment effects from the paired and two sample t-tests. We used simulations to calculate the empirical size and power of the test statistics, as well as the bias, mean square and confidence interval width of the corresponding estimators. The proposed method provides an effective tool to evaluate data from clinical trials and similar comparative studies. Copyright © 2013 John Wiley & Sons, Ltd.

An inter-laboratory comparison study of the ANSI/BIFMA standard test method M7.1 for furniture

EPA Science Inventory

Five laboratories using five different test chambers participated in the study to quantify within- and between-laboratory variability in the measurement of emissions of volatile organic compounds (VOCs) from new commercial furniture test items following ANSI/BIFMA M7.1. Test item...

Collaborative Test Reviews: Student Performance

ERIC Educational Resources Information Center

Bhatia, Anuradha; Makela, Carole J.

2010-01-01

A group study method proved helpful in improving senior-level students' performance on unit tests through collaborative learning. Students of a History of Textiles course voluntarily attended study sessions to review course content and prepare for unit tests. The students who attended the group reviews scored better on tests than those who did…

Assessment of cosmetic ingredients in the in vitro reconstructed human epidermis test method EpiSkin™ using HPLC/UPLC-spectrophotometry in the MTT-reduction assay.

PubMed

Alépée, N; Hibatallah, J; Klaric, M; Mewes, K R; Pfannenbecker, U; McNamee, P

2016-06-01

Cosmetics Europe recently established HPLC/UPLC-spectrophotometry as a suitable alternative endpoint detection system for measurement of formazan in the MTT-reduction assay of reconstructed human tissue test methods irrespective of the test system involved. This addressed a known limitation for such test methods that use optical density for measurement of formazan and may be incompatible for evaluation of strong MTT reducer and/or coloured chemicals. To build on the original project, Cosmetics Europe has undertaken a second study that focuses on evaluation of chemicals with functionalities relevant to cosmetic products. Such chemicals were primarily identified from the Scientific Committee on Consumer Safety (SCCS) 2010 memorandum (addendum) on the in vitro test EpiSkin™ for skin irritation testing. Fifty test items were evaluated in which both standard photometry and HPLC/UPLC-spectrophotometry were used for endpoint detection. The results obtained in this study: 1) provide further support for Within Laboratory Reproducibility of HPLC-UPLC-spectrophotometry for measurement of formazan; 2) demonstrate, through use a case study with Basazol C Blue pr. 8056, that HPLC/UPLC-spectrophotometry enables determination of an in vitro classification even when this is not possible using standard photometry and 3) addresses the question raised by SCCS in their 2010 memorandum (addendum) to consider an endpoint detection system not involving optical density quantification in in vitro reconstructed human epidermis skin irritation test methods. Copyright © 2016 Elsevier Ltd. All rights reserved.

Does the Irlen[R] Method Bring about an Increase in Reading Scores on a Specific Test of Reading for Students Found to Have Scotopic Sensitivity Syndrome?

ERIC Educational Resources Information Center

Faraci, Marie Elaine

2009-01-01

The problem. The purpose of this study was to examine the effect of the Irlen[R] method's use of colored overlays on the reading achievement of 3rd-grade students who were identified as having Scotopic Sensitivity Syndrome/Irlen[R] Syndrome. Method. This was a true experimental, pre-test, post-test design. The Irlen[R] overlay, either present…

Revealing barriers and facilitators to use a new genetic test: comparison of three user involvement methods.

PubMed

Rhebergen, Martijn D F; Visser, Maaike J; Verberk, Maarten M; Lenderink, Annet F; van Dijk, Frank J H; Kezic, Sanja; Hulshof, Carel T J

2012-10-01

We compared three common user involvement methods in revealing barriers and facilitators from intended users that might influence their use of a new genetic test. The study was part of the development of a new genetic test on the susceptibility to hand eczema for nurses. Eighty student nurses participated in five focus groups (n = 33), 15 interviews (n = 15) or questionnaires (n = 32). For each method, data were collected until saturation. We compared the mean number of items and relevant remarks that could influence the use of the genetic test obtained per method, divided by the number of participants in that method. Thematic content analysis was performed using MAXQDA software. The focus groups revealed 30 unique items compared to 29 in the interviews and 21 in the questionnaires. The interviews produced more items and relevant remarks per participant (1.9 and 8.4 pp) than focus groups (0.9 and 4.8 pp) or questionnaires (0.7 and 2.3 pp). All three involvement methods revealed relevant barriers and facilitators to use a new genetic test. Focus groups and interviews revealed substantially more items than questionnaires. Furthermore, this study suggests a preference for the use of interviews because the number of items per participant was higher than for focus groups and questionnaires. This conclusion may be valid for other genetic tests as well.

EVALUATION OF THE ROBUSTNESS OF THE FATHEAD MINNOW, PIMEPHALES PROMELAS, LARVAL SURVIVAL AND GROWTH TEST, U.S. EPA METHOD 1000.0

EPA Science Inventory

An intralaboratory study was conducted to evaluate the robustness of the Fathead Minnow (Pimephales promelas) Larval Survival and Growth Test, Method 1000.0 Toxicity tests were conducted with the reference toxicants hexavalent chromium (Cr6+) and copper (Cu), and the data were st...

Nondestructive Testing Eddy Current Equipment, Methods and Applications RQA/M1-5330.12 (V-II).

ERIC Educational Resources Information Center

National Aeronautics and Space Administration, Huntsville, AL. George C. Marshall Space Flight Center.

As one in the series of programmed instruction handbooks, prepared by the U. S. space program, home study material is presented in this volume concerning familiarization and orientation on eddy current testing. The subject is presented under the following headings: Test Coils, Methods and Indications, and Applications. High product quality and…

Comparison of real-time PCR with disk diffusion, agar screen and E-test methods for detection of methicillin-resistant Staphylococcus aureus.

PubMed

Shariati, Laleh; Validi, Majid; Tabatabaiefar, Mohammad Amin; Karimi, Ali; Nafisi, Mohammad Reza

2010-12-01

Methicillin-resistant Staphylococcus aureus (MRSA) is a nosocomial pathogen. Our main objective was to compare oxacillin disk test, oxacillin E-test, and oxacillin agar screen for detection of methicillin resistance in S. aureus, using real-time PCR for mecA as the "gold standard" comparison assay. 196 S. aureus isolates were identified out of 284 Staphylococcus isolates. These isolates were screened for MRSA with several methods: disk diffusion, agar screen (6.0 μg/ml), oxacillin E-test, and real-time PCR for detection of mecA gene. Of the 196 S. aureus isolates tested, 96 isolates (49%) were mecA-positive and 100 isolates (51%) mecA-negative. All methods tested had a statistically significant agreement with real-time PCR. E-test was 100% sensitive and specific for mecA presence. The sensitivity and specificity of oxacillin agar screen method were 98 and 99%, respectively and sensitivity and specificity of oxacillin disk diffusion method were 95 and 93%, respectively. In the present study, oxacillin E-test is proposed as the best phenotypic method. For economic reasons, the oxacillin agar screen method (6.0 μg/ml), which is suitable for the detection of MRSA, is recommended due to its accuracy and low cost.

The Effect of Social and Token Economy Reinforcements on Academic Achievement of Students with Intellectual Disabilities

PubMed Central

Ashoori, Mohammad; Sereshki, Narges Adib

2011-01-01

Objective This study investigates the effect of social and token economy reinforcements on academic achievement of 9th grade boy students with intellectual disabilities in an experimental science class in Tehran Province. Method The method used for this study was experimental by pre-test, post- test with a control group. The boy students with intellectual disabilities from three junior high schools participated in this study. The sample consisted of thirty, 9th grade boy students with intellectual disabilities in the selected schools; the schools were chosen by the multi-stage cluster method. To measure the progress of students in the science class, a teacher made test and the Wechsler intelligence test for matching the groups for IQ were used. To ensure validity, the content validity criteria depended tests calculated by the Lashe method and teachers' perspective were used. The reliability coefficient was obtained by the reliability coefficient of related tests; the percent agreement method and the obtained data were analyzed using one-way variance analysis and Shefe prosecution test. Results The results showed that there was a significant increase in academic achievement of students with intellectual disabilities when using token economy than using social reinforcements compared with the control group. Also, when using social reinforcements, the academic achievement of students was more than the control group. Conclusion Token economy and social reinforcements increased the academic achievement of students with intellectual disabilities in the science class; and also the effect of token economy reinforcements was more than social reinforcements on the subjects. PMID:22952517

Testing procedures for carbon fiber reinforced plastic components

NASA Technical Reports Server (NTRS)

Gosse, H. J.; Kaitatzidi, M.; Roth, S.

1977-01-01

Tests for studying the basic material are considered and quality control investigations involving preimpregnated materials (prepreg) are discussed. Attention is given to the prepreg area weight, the fiber area weight of prepregs, the resin content, volatile components, the effective thickness, resin flow, the resistance to bending strain, tensile strength, and shear strength. A description of tests conducted during the manufacturing process is also presented, taking into account X-ray methods, approaches of neutron radiography, ultrasonic procedures, resonance methods and impedance studies.

Improvement of human cell line activation test (h-CLAT) using short-time exposure methods for prevention of false-negative results.

PubMed

Narita, Kazuto; Ishii, Yuuki; Vo, Phuc Thi Hong; Nakagawa, Fumiko; Ogata, Shinichi; Yamashita, Kunihiko; Kojima, Hajime; Itagaki, Hiroshi

2018-01-01

Recently, animal testing has been affected by increasing ethical, social, and political concerns regarding animal welfare. Several in vitro safety tests for evaluating skin sensitization, such as the human cell line activation test (h-CLAT), have been proposed. However, similar to other tests, the h-CLAT has produced false-negative results, including in tests for acid anhydride and water-insoluble chemicals. In a previous study, we demonstrated that the cause of false-negative results from phthalic anhydride was hydrolysis by an aqueous vehicle, with IL-8 release from THP-1 cells, and that short-time exposure to liquid paraffin (LP) dispersion medium could reduce false-negative results from acid anhydrides. In the present study, we modified the h-CLAT by applying this exposure method. We found that the modified h-CLAT is a promising method for reducing false-negative results obtained from acid anhydrides and chemicals with octanol-water partition coefficients (LogK ow ) greater than 3.5. Based on the outcomes from the present study, a combination of the original and the modified h-CLAT is suggested for reducing false-negative results. Notably, the combination method provided a sensitivity of 95% (overall chemicals) or 93% (chemicals with LogK ow > 2.0), and an accuracy of 88% (overall chemicals) or 81% (chemicals with LogK ow > 2.0). We found that the combined method is a promising evaluation scheme for reducing false-negative results seen in existing in vitro skin-sensitization tests. In the future, we expect a combination of original and modified h-CLAT to be applied in a newly developed in vitro test for evaluating skin sensitization.

Vacuum decay container/closure integrity testing technology. Part 1. ASTM F2338-09 precision and bias studies.

PubMed

Wolf, Heinz; Stauffer, Tony; Chen, Shu-Chen Y; Lee, Yoojin; Forster, Ronald; Ludzinski, Miron; Kamat, Madhav; Godorov, Phillip; Guazzo, Dana Morton

2009-01-01

ASTM F2338-09 Standard Test Method for Nondestructive Detection of Leaks in Packages by Vacuum Decay Method is applicable for leak-testing rigid and semi-rigid non-lidded trays; trays or cups sealed with porous barrier lidding materials; rigid, nonporous packages; and flexible, nonporous packages. Part 1 of this series describes the precision and bias studies performed in 2008 to expand this method's scope to include rigid, nonporous packages completely or partially filled with liquid. Round robin tests using three VeriPac 325/LV vacuum decay leak testers (Packaging Technologies & Inspection, LLC, Tuckahoe, NY) were performed at three test sites. Test packages were 1-mL glass syringes. Positive controls had laser-drilled holes in the barrel ranging from about 5 to 15 microm in nominal diameter. Two different leak tests methods were performed at each site: a "gas leak test" performed at 250 mbar (absolute) and a "liquid leak test" performed at about 1 mbar (absolute). The gas leak test was used to test empty, air-filled syringes. All defects with holes > or = 5.0 microm and all no-defect controls were correctly identified. The only false negative result was attributed to a single syringe with a < 5.0-microm hole. Tests performed using a calibrated air leak supported a 0.10-cm3 x min(-1) (ccm) sensitivity limit (99/99 lower tolerance limit). The liquid leak test was used to test both empty, air-filled syringes and water-filled syringes. Test results were 100% accurate for all empty and water-filled syringes, both without holes and with holes (5, 10, and 15 microm). Tests performed using calibrated air flow leaks of 0, 0.05, and 0.10 ccm were also 100% accurate; data supported a 0.10-ccm sensitivity limit (99/99 lower tolerance limit). Quantitative differential pressure results strongly correlated to hole size using either liquid or gas vacuum decay leak tests. The higher vacuum liquid leak test gave noticeably higher pressure readings when water was present in the defect. Both the ASTM F2338-09 test method and the precision and bias study report are available by contacting ASTM International in West Conshohocken, PA, USA (www.astm.org).

A comparison of in vitro cytotoxicity assays in medical device regulatory studies.

PubMed

Liu, Xuemei; Rodeheaver, Denise P; White, Jeffrey C; Wright, Ann M; Walker, Lisa M; Zhang, Fan; Shannon, Stephen

2018-06-06

Medical device biocompatibility testing is used to evaluate the risk of adverse effects on tissues from exposure to leachates/extracts. A battery of tests is typically recommended in accordance with regulatory standards to determine if the device is biocompatible. In vitro cytotoxicity, a key element of the standards, is a required endpoint for all types of medical devices. Each validated cytotoxicity method has different methodology and acceptance criteria that could influence the selection of a specific test. In addition, some guidances are more specific than others as to the recommended test methods. For example, the International Organization for Standardization (ISO 1 ) cites preference for quantitative methods (e.g., tetrazolium (MTT/XTT), neutral red (NR), or colony formation assays (CFA)) over qualitative methods (e.g., elution, agar overlay/diffusion, or direct), while a recent ISO standard for contact lens/lens care solutions specifically requires a qualitative direct test. Qualitative methods are described in United States Pharmacopeia (USP) while quantitative CFAs are listed in Japan guidance. The aim of this review is to compare the methodologies such as test article preparation, test conditions, and criteria for six cytotoxicity methods recommended in regulatory standards in order to inform decisions on which method(s) to select during the medical device safety evaluation. Copyright © 2018. Published by Elsevier Inc.

Validation studies and proficiency testing.

PubMed

Ankilam, Elke; Heinze, Petra; Kay, Simon; Van den Eede, Guy; Popping, Bert

2002-01-01

Genetically modified organisms (GMOs) entered the European food market in 1996. Current legislation demands the labeling of food products if they contain <1% GMO, as assessed for each ingredient of the product. To create confidence in the testing methods and to complement enforcement requirements, there is an urgent need for internationally validated methods, which could serve as reference methods. To date, several methods have been submitted to validation trials at an international level; approaches now exist that can be used in different circumstances and for different food matrixes. Moreover, the requirement for the formal validation of methods is clearly accepted; several national and international bodies are active in organizing studies. Further validation studies, especially on the quantitative polymerase chain reaction methods, need to be performed to cover the rising demand for new extraction methods and other background matrixes, as well as for novel GMO constructs.

Exploration of analysis methods for diagnostic imaging tests: problems with ROC AUC and confidence scores in CT colonography.

PubMed

Mallett, Susan; Halligan, Steve; Collins, Gary S; Altman, Doug G

2014-01-01

Different methods of evaluating diagnostic performance when comparing diagnostic tests may lead to different results. We compared two such approaches, sensitivity and specificity with area under the Receiver Operating Characteristic Curve (ROC AUC) for the evaluation of CT colonography for the detection of polyps, either with or without computer assisted detection. In a multireader multicase study of 10 readers and 107 cases we compared sensitivity and specificity, using radiological reporting of the presence or absence of polyps, to ROC AUC calculated from confidence scores concerning the presence of polyps. Both methods were assessed against a reference standard. Here we focus on five readers, selected to illustrate issues in design and analysis. We compared diagnostic measures within readers, showing that differences in results are due to statistical methods. Reader performance varied widely depending on whether sensitivity and specificity or ROC AUC was used. There were problems using confidence scores; in assigning scores to all cases; in use of zero scores when no polyps were identified; the bimodal non-normal distribution of scores; fitting ROC curves due to extrapolation beyond the study data; and the undue influence of a few false positive results. Variation due to use of different ROC methods exceeded differences between test results for ROC AUC. The confidence scores recorded in our study violated many assumptions of ROC AUC methods, rendering these methods inappropriate. The problems we identified will apply to other detection studies using confidence scores. We found sensitivity and specificity were a more reliable and clinically appropriate method to compare diagnostic tests.

Comparison of Fecal Collection Methods for Microbiota Studies in Bangladesh

PubMed Central

Chen, Jun; Kibriya, Muhammad G.; Chen, Yu; Islam, Tariqul; Eunes, Mahbubul; Ahmed, Alauddin; Naher, Jabun; Rahman, Anisur; Amir, Amnon; Shi, Jianxin; Abnet, Christian C.; Nelson, Heidi; Knight, Rob; Chia, Nicholas; Ahsan, Habibul; Sinha, Rashmi

2017-01-01

ABSTRACT To our knowledge, fecal microbiota collection methods have not been evaluated in low- and middle-income countries. Therefore, we evaluated five different fecal sample collection methods for technical reproducibility, stability, and accuracy within the Health Effects of Arsenic Longitudinal Study (HEALS) in Bangladesh. Fifty participants from the HEALS provided fecal samples in the clinic which were aliquoted into no solution, 95% ethanol, RNAlater, postdevelopment fecal occult blood test (FOBT) cards, and fecal immunochemical test (FIT) tubes. Half of the aliquots were frozen immediately at −80°C (day 0) and the remaining samples were left at ambient temperature for 96 h and then frozen (day 4). Intraclass correlation coefficients (ICC) were calculated for the relative abundances of the top three phyla, for two alpha diversity measures, and for four beta diversity measures. The duplicate samples had relatively high ICCs for technical reproducibility at day 0 and day 4 (range, 0.79 to 0.99). The FOBT card and samples preserved in RNAlater and 95% ethanol had the highest ICCs for stability over 4 days. The FIT tube had lower stability measures overall. In comparison to the “gold standard” method using immediately frozen fecal samples with no solution, the ICCs for many of the microbial metrics were low, but the rank order appeared to be preserved as seen by the Spearman correlation. The FOBT cards, 95% ethanol, and RNAlater were effective fecal preservatives. These fecal collection methods are optimal for future cohort studies, particularly in low- and middle-income countries. IMPORTANCE The collection of fecal samples in prospective cohort studies is essential to provide the opportunity to study the effect of the human microbiota on numerous health conditions. However, these collection methods have not been adequately tested in low- and middle-income countries. We present estimates of technical reproducibility, stability at ambient temperature for 4 days, and accuracy comparing a “gold standard” for fecal samples in no solution, 95% ethanol, RNAlater, postdevelopment fecal occult blood test cards, and fecal immunochemical test tubes in a study conducted in Bangladesh. Fecal occult blood test cards and fecal samples stored in 95% ethanol or RNAlater adequately preserve fecal samples in this setting. Therefore, new studies in low- and middle-income countries should include collection of fecal samples using fecal occult blood test cards, 95% ethanol, or RNAlater for prospective cohort studies. PMID:28258145

Diagnosing systemic lupus erythematosus: new-generation immunoassays for measurement of anti-dsDNA antibodies are an effective alternative to the Farr technique and the Crithidia luciliae immunofluorescence test.

PubMed

Antico, A; Platzgummer, S; Bassetti, D; Bizzaro, N; Tozzoli, R; Villalta, D

2010-07-01

The aim of this study was to evaluate the diagnostic performance of four new enzyme immunoassays (EIAs) for anti-double-stranded-DNA (anti-dsDNA) antibodies, in comparison with the Farr assay and the Crithidia luciliae immunofluorescence test (CLIFT). To this purpose, sera from four patient groups were collected: 52 sera from patients with systemic lupus erythematosus (SLE); 28 from patients with other connective tissue diseases (CTD); 36 from patients with hepatitis C virus (HCV) infection; and 24 from those with acute viral infection. All sera were tested for anti-dsDNA antibodies by four EIA methods using a different antigenic DNA source [synthetic oligonucleotide (Method A), circular plasmid (Method B), recombinant (Method C), and purified extracted (Method D)], and by CLIFT and Farr assays. The diagnostic sensitivity of the assays was as follows: 84.6% (Method A), 73% (B), 82.7% (C), 84.6% (D), 55.8% (CLIFT), and 78.8% (Farr). Specificity was 82.9% (A), 97.7% (B), 96.5% (C), 94.3% (D), 96.5% (CLIFT), and 90.9% (Farr). From these data, we can conclude that the new-generation EIA methods evaluated in this study have higher sensitivity than the CLIFT and Farr assays and, with the exception of Method A, have specificity similar to the CLIFT and slightly higher than the Farr assay. These findings suggest that EIA tests may replace CLIFT as a screening test and the Farr assay as a specific test, for anti-dsDNA antibody detection.

Evaluation of DuPont Qualicon Bax System PCR assay for yeast and mold.

PubMed

Wallace, F Morgan; Burns, Frank; Fleck, Lois; Andaloro, Bridget; Farnum, Andrew; Tice, George; Ruebl, Joanne

2010-01-01

Evaluations were conducted to test the performance of the BAX System PCR assay which was certified as Performance Tested Method 010902 for screening yeast and mold in yogurt, corn starch, and milk-based powdered infant formula. Method comparison studies performed on samples with low-level inoculates showed that the BAX System demonstrates a sensitivity equivalent to the U.S. Food and Drug Administration's Bacteriological Analytical Manual culture method, but with a significantly shorter time to obtain results. Tests to evaluate inclusivity and exclusivity returned no false-negative and no false-positive results on a diverse panel of isolates, and tests for lot-to-lot variability and tablet stability demonstrated consistent performance. Ruggedness studies determined that none of the factors examined affected the performance of the assay.

Comparison of chemiluminescence methods for analysis of hydrogen peroxide and hydroxyl radicals

NASA Astrophysics Data System (ADS)

Pehrman, R.; Amme, M.; Cachoir, C.

2006-01-01

Assessment of alpha radiolysis influence on the chemistry of geologically disposed spent fuel demands analytical methods for radiolytic product determination at trace levels. Several chemiluminescence methods for the detection of radiolytic oxidants hydrogen peroxide and hydroxyl radicals are tested. Two of hydrogen peroxide methods use luminol, catalyzed by either μ-peroxidase or hemin, one uses 10-methyl-9-(p-formylphenyl)-acridinium carboxylate trifluoromethanesulfonate and one potassium periodate. All recipes are tested as batch systems in basic conditions. For hydroxyl radical detection luminophores selected are 3-hydroxyphthalic hydrazide and rutin. Both methods are tested as batch systems. The results are compared and the applicability of the methods for near-field dissolution studies is discussed.

Performance of CarbaNP and CIM tests in OXA-48 carbapenemase-producing Enterobacteriaceae.

PubMed

Yıldız, Serap Süzük; Kaşkatepe, Banu; Avcıküçük, Havva; Öztürk, Şükran

2017-03-01

This study applied two phenotypic tests, namely "Carbapenemase Nordmann-Poirel" (CarbaNP) test and "Carbapenem Inactivation Method" (CIM), against the isolates carrying the carbapenem resistance genes. The study included 83 carbapenem-resistant Enterobacteriaceae isolates producing oxacillinase-48 (OXA-48) and 30 carbapenem-sensitive Enterobacteriaceae isolates. Out of the total isolates studied, 77 isolates (92.77%) were identified as Klebsiella pneumoniae and six isolates (7.23%) were identified as Escherichia coli by Matrix Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry. Polymerase chain reaction (PCR) method used to detect resistance genes found that 74 isolates (89.16%) produced OXA-48 carbapenemase, whereas nine isolates (10.84%) produced both OXA-48 and New Delhi metallo-beta-lactamase-1 (NDM-1). The isolates producing both OXA-48 and NDM-1 were found to be positive by both phenotypic tests. Among isolates carrying only bla OXA-48 gene alone, nine isolates (13.04%) for CarbaNP test and two isolates for CIM test (2.90%) displayed false negative results, respectively. The sensitivity of CarbaNP and CIM tests was found to be 89.16% and 97.59%, respectively, whereas the specificity was determined to be 100% for both tests. These findings suggest that CarbaNP and CIM tests are useful tools to identify the carbapenemase producers. Molecular methods like PCR are recommended to verify false negative tests predicted to have OXA-48 activity.

Study on the method to test large-aperture hyperboloid convex mirror

NASA Astrophysics Data System (ADS)

Meng, Xiaohui; Dong, Huiwen; Guo, Wen; Wang, Huijun

2014-08-01

There are numerous reflecting optical system designs that call for large-aperture convex surfaces, such as secondary mirror in on-axis three mirror anastigmatic (TMA). Several methods to test high accuracy hyperboloid convex surfaces are introduced separately in this paper. A kind of arrangement is chosen to test a surface with diameter of 420mm, radius of 1371mm, and conic K -2.1229. The CGH compensator for testing is designed, which is made up of illumination lens and hologram test plate with designed residual wavefront aberration less than 0.001λ (RMS). The second transmitted method that is equipped with a technical flat surface coating by Ag film in the bottom of surface mirror under test, which form an auto-collimation optical system to eliminate the aberration. The Hindle-Simpson test that requires a larger meniscus lens to compensate the optical aberration, and the designed result of optical test system is less than 0.0016λ. Contrasting the CGH compensator and the second transmitted method, the Hindle-Simpson testing method has the advantage of it is easily to manufacture and adjust; meanwhile the test result is stable and has been less affected by the environment. It has been found that the method is rational and reliable, and it can fulfill the requirement of manufacturing and testing process for hyperboloid convex mirrors.

Estimation and test for linkage between markers: a comparison of lod score and χ (2) test in a linkage study of maritime pine (Pinus pinaster Ait.).

PubMed

Gerber, S; Rodolphe, F

1994-06-01

The first step in the construction of a linkage map involves the estimation and test for linkage between all possible pairs of markers. The lod score method is used in many linkage studies for the latter purpose. In contrast with classical statistical tests, this method does not rely on the choice of a first-type error level. We thus provide a comparison between the lod score and a χ (2) test on linkage data from a gymnosperm, the maritime pine. The lod score appears to be a very conservative test with the usual thresholds. Its severity depends on the type of data used.

Methods in pharmacoepidemiology: a review of statistical analyses and data reporting in pediatric drug utilization studies.

PubMed

Sequi, Marco; Campi, Rita; Clavenna, Antonio; Bonati, Maurizio

2013-03-01

To evaluate the quality of data reporting and statistical methods performed in drug utilization studies in the pediatric population. Drug utilization studies evaluating all drug prescriptions to children and adolescents published between January 1994 and December 2011 were retrieved and analyzed. For each study, information on measures of exposure/consumption, the covariates considered, descriptive and inferential analyses, statistical tests, and methods of data reporting was extracted. An overall quality score was created for each study using a 12-item checklist that took into account the presence of outcome measures, covariates of measures, descriptive measures, statistical tests, and graphical representation. A total of 22 studies were reviewed and analyzed. Of these, 20 studies reported at least one descriptive measure. The mean was the most commonly used measure (18 studies), but only five of these also reported the standard deviation. Statistical analyses were performed in 12 studies, with the chi-square test being the most commonly performed test. Graphs were presented in 14 papers. Sixteen papers reported the number of drug prescriptions and/or packages, and ten reported the prevalence of the drug prescription. The mean quality score was 8 (median 9). Only seven of the 22 studies received a score of ≥10, while four studies received a score of <6. Our findings document that only a few of the studies reviewed applied statistical methods and reported data in a satisfactory manner. We therefore conclude that the methodology of drug utilization studies needs to be improved.

TECRA Unique test for rapid detection of Salmonella in food: collaborative study.

PubMed

Hughes, D; Dailianis, A E; Hill, L; McIntyre, D A; Anderson, A

2001-01-01

The TECRA Unique Salmonella test uses the principle of immunoenrichment to allow rapid detection of Salmonellae in food. A collaborative study was conducted to compare the TECRA Salmonella Unique test with the reference culture method given in the U.S. Food and Drug Administration's Bacteriological Analytical Manual. Three food types (milk powder, pepper, and soy flour) were analyzed in Australia and 2 food types (milk chocolate and dried egg) were analyzed in the United States. Forty-one collaborators participated in the study. For each of the 5 foods at each of the 3 levels, a comparison showed no significant differences (p > or = 0.05) in the proportion of positive test samples for Unique and that for the reference method using the Chi-square test for independence with continuity correction.

Determination of Failure Point of Asphalt-Mixture Fatigue-Test Results Using the Flow Number Method

NASA Astrophysics Data System (ADS)

Wulan, C. E. P.; Setyawan, A.; Pramesti, F. P.

2018-03-01

The failure point of the results of fatigue tests of asphalt mixtures performed in controlled stress mode is difficult to determine. However, several methods from empirical studies are available to solve this problem. The objectives of this study are to determine the fatigue failure point of the results of indirect tensile fatigue tests using the Flow Number Method and to determine the best Flow Number model for the asphalt mixtures tested. In order to achieve these goals, firstly the best asphalt mixture of three was selected based on their Marshall properties. Next, the Indirect Tensile Fatigue Test was performed on the chosen asphalt mixture. The stress-controlled fatigue tests were conducted at a temperature of 20°C and frequency of 10 Hz, with the application of three loads: 500, 600, and 700 kPa. The last step was the application of the Flow Number methods, namely the Three-Stages Model, FNest Model, Francken Model, and Stepwise Method, to the results of the fatigue tests to determine the failure point of the specimen. The chosen asphalt mixture is EVA (Ethyl Vinyl Acetate) polymer -modified asphalt mixture with 6.5% OBC (Optimum Bitumen Content). Furthermore, the result of this study shows that the failure points of the EVA-modified asphalt mixture under loads of 500, 600, and 700 kPa are 6621, 4841, and 611 for the Three-Stages Model; 4271, 3266, and 537 for the FNest Model; 3401, 2431, and 421 for the Francken Model, and 6901, 6841, and 1291 for the Stepwise Method, respectively. These different results show that the bigger the loading, the smaller the number of cycles to failure. However, the best FN results are shown by the Three-Stages Model and the Stepwise Method, which exhibit extreme increases after the constant development of accumulated strain.

New methods of testing nonlinear hypothesis using iterative NLLS estimator

NASA Astrophysics Data System (ADS)

Mahaboob, B.; Venkateswarlu, B.; Mokeshrayalu, G.; Balasiddamuni, P.

2017-11-01

This research paper discusses the method of testing nonlinear hypothesis using iterative Nonlinear Least Squares (NLLS) estimator. Takeshi Amemiya [1] explained this method. However in the present research paper, a modified Wald test statistic due to Engle, Robert [6] is proposed to test the nonlinear hypothesis using iterative NLLS estimator. An alternative method for testing nonlinear hypothesis using iterative NLLS estimator based on nonlinear hypothesis using iterative NLLS estimator based on nonlinear studentized residuals has been proposed. In this research article an innovative method of testing nonlinear hypothesis using iterative restricted NLLS estimator is derived. Pesaran and Deaton [10] explained the methods of testing nonlinear hypothesis. This paper uses asymptotic properties of nonlinear least squares estimator proposed by Jenrich [8]. The main purpose of this paper is to provide very innovative methods of testing nonlinear hypothesis using iterative NLLS estimator, iterative NLLS estimator based on nonlinear studentized residuals and iterative restricted NLLS estimator. Eakambaram et al. [12] discussed least absolute deviation estimations versus nonlinear regression model with heteroscedastic errors and also they studied the problem of heteroscedasticity with reference to nonlinear regression models with suitable illustration. William Grene [13] examined the interaction effect in nonlinear models disused by Ai and Norton [14] and suggested ways to examine the effects that do not involve statistical testing. Peter [15] provided guidelines for identifying composite hypothesis and addressing the probability of false rejection for multiple hypotheses.

16 CFR 1000.29 - Directorate for Engineering Sciences.

Code of Federal Regulations, 2010 CFR

2010-01-01

... standards, product safety tests and test methods, performance criteria, design specifications, and quality control standards for consumer products, based on engineering and scientific methods. It conducts... consumer interest groups. The Directorate conducts human factors studies and research of consumer product...

16 CFR 1000.29 - Directorate for Engineering Sciences.

Code of Federal Regulations, 2012 CFR

2012-01-01

... standards, product safety tests and test methods, performance criteria, design specifications, and quality control standards for consumer products, based on engineering and scientific methods. It conducts... consumer interest groups. The Directorate conducts human factors studies and research of consumer product...

Comparison of bulk sediment and sediment elutriate toxicity testing methods

EPA Science Inventory

Elutriate bioassays are among numerous methods that exist for assessing the potential toxicity of sediments in aquatic systems. In this study, interlaboratory results were compared from 96-hour Ceriodaphnia dubia and Pimephales promelas static-renewal acute toxicity tests conduct...

Mechanical testing of internal fixation devices: A theoretical and practical examination of current methods.

PubMed

Grant, Caroline A; Schuetz, Michael; Epari, Devakar

2015-11-26

Successful healing of long bone fractures is dependent on the mechanical environment created within the fracture, which in turn is dependent on the fixation strategy. Recent literature reports have suggested that locked plating devices are too stiff to reliably promote healing. However, in vitro testing of these devices has been inconsistent in both method of constraint and reported outcomes, making comparisons between studies and the assessment of construct stiffness problematic. Each of the methods previously used in the literature were assessed for their effect on the bending of the sample and concordant stiffness. The choice of outcome measures used in in vitro fracture studies was also assessed. Mechanical testing was conducted on seven hole locked plated constructs in each method for comparison. Based on the assessment of each method the use of spherical bearings, ball joints or similar is suggested at both ends of the sample. The use of near and far cortex movement was found to be more comprehensive and more accurate than traditional centrally calculated interfragmentary movement values; stiffness was found to be highly susceptible to the accuracy of deformation measurements and constraint method, and should only be used as a within study comparison method. The reported stiffness values of locked plate constructs from in vitro mechanical testing is highly susceptible to testing constraints and output measures, with many standard techniques overestimating the stiffness of the construct. This raises the need for further investigation into the actual mechanical behaviour within the fracture gap of these devices. Copyright © 2015 Elsevier Ltd. All rights reserved.

Comparison of the transformation temperatures of heat-activated Nickel-Titanium orthodontic archwires by two different techniques.

PubMed

Obaisi, Noor Aminah; Galang-Boquiren, Maria Therese S; Evans, Carla A; Tsay, Tzong Guang Peter; Viana, Grace; Berzins, David; Megremis, Spiro

2016-07-01

The purpose of this study was to investigate the suitability of the Bend and Free Recovery (BFR) method as a standard test method to determine the transformation temperatures of heat-activated Ni-Ti orthodontic archwires. This was done by determining the transformation temperatures of two brands of heat-activated Ni-Ti orthodontic archwires using the both the BFR method and the standard method of Differential Scanning Calorimetry (DSC). The values obtained from the two methods were compared with each other and to the manufacturer-listed values. Forty heat-activated Ni-Ti archwires from both Rocky Mountain Orthodontics (RMO) and Opal Orthodontics (Opal) were tested using BFR and DSC. Round (0.016 inches) and rectangular (0.019×0.025 inches) archwires from each manufacturer were tested. The austenite start temperatures (As) and austenite finish temperatures (Af) were recorded. For four of the eight test groups, the BFR method resulted in lower standard deviations than the DSC method, and, overall, the average standard deviation for BFR testing was slightly lower than for DSC testing. Statistically significant differences were seen between the transformation temperatures obtained from the BFR and DSC test methods. However, the Af temperatures obtained from the two methods were remarkably similar with the mean differences ranging from 0.0 to 2.1°C: Af Opal round (BFR 26.7°C, DSC 27.6°C) and rectangular (BFR 27.6°C, DSC 28.6°C); Af RMO round (BFR 25.5°C, DSC 25.5°C) and rectangular (BFR 28.0°C, DSC 25.9°C). Significant differences were observed between the manufacturer-listed transformation temperatures and those obtained with BFR and DSC testing for both manufacturers. The results of this study suggest that the Bend and Free Recovery method is suitable as a standard method to evaluate the transformation temperatures of heat-activated Ni-Ti orthodontic archwires. Copyright © 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Laser notching ceramics for reliable fracture toughness testing

DOE PAGES

Barth, Holly D.; Elmer, John W.; Freeman, Dennis C.; ...

2015-09-19

A new method for notching ceramics was developed using a picosecond laser for fracture toughness testing of alumina samples. The test geometry incorporated a single-edge-V-notch that was notched using picosecond laser micromachining. This method has been used in the past for cutting ceramics, and is known to remove material with little to no thermal effect on the surrounding material matrix. This study showed that laser-assisted-machining for fracture toughness testing of ceramics was reliable, quick, and cost effective. In order to assess the laser notched single-edge-V-notch beam method, fracture toughness results were compared to results from other more traditional methods, specificallymore » surface-crack in flexure and the chevron notch bend tests. Lastly, the results showed that picosecond laser notching produced precise notches in post-failure measurements, and that the measured fracture toughness results showed improved consistency compared to traditional fracture toughness methods.« less

The Objective Borderline Method: A Probabilistic Method for Standard Setting

ERIC Educational Resources Information Center

Shulruf, Boaz; Poole, Phillippa; Jones, Philip; Wilkinson, Tim

2015-01-01

A new probability-based standard setting technique, the Objective Borderline Method (OBM), was introduced recently. This was based on a mathematical model of how test scores relate to student ability. The present study refined the model and tested it using 2500 simulated data-sets. The OBM was feasible to use. On average, the OBM performed well…

Survey of the Methods and Reporting Practices in Published Meta-analyses of Test Performance: 1987 to 2009

ERIC Educational Resources Information Center

Dahabreh, Issa J.; Chung, Mei; Kitsios, Georgios D.; Terasawa, Teruhiko; Raman, Gowri; Tatsioni, Athina; Tobar, Annette; Lau, Joseph; Trikalinos, Thomas A.; Schmid, Christopher H.

2013-01-01

We performed a survey of meta-analyses of test performance to describe the evolution in their methods and reporting. Studies were identified through MEDLINE (1966-2009), reference lists, and relevant reviews. We extracted information on clinical topics, literature review methods, quality assessment, and statistical analyses. We reviewed 760…

The Performance of Methods to Test Upper-Level Mediation in the Presence of Nonnormal Data

ERIC Educational Resources Information Center

Pituch, Keenan A.; Stapleton, Laura M.

2008-01-01

A Monte Carlo study compared the statistical performance of standard and robust multilevel mediation analysis methods to test indirect effects for a cluster randomized experimental design under various departures from normality. The performance of these methods was examined for an upper-level mediation process, where the indirect effect is a fixed…

The Development of a New Method of Idiographic Measurement for Dynamic Assessment Intervention

ERIC Educational Resources Information Center

Hurley, Emma; Murphy, Raegan

2015-01-01

This paper proposes a new method of idiographic measurement for dynamic assessment (DA) intervention. There are two main methods of measurement for DA intervention; split-half tests and integrated scoring systems. Split-half tests of ability have proved useful from a research perspective. Integrated scoring systems coupled with case studies are…

Statistical methods used to test for agreement of medical instruments measuring continuous variables in method comparison studies: a systematic review.

PubMed

Zaki, Rafdzah; Bulgiba, Awang; Ismail, Roshidi; Ismail, Noor Azina

2012-01-01

Accurate values are a must in medicine. An important parameter in determining the quality of a medical instrument is agreement with a gold standard. Various statistical methods have been used to test for agreement. Some of these methods have been shown to be inappropriate. This can result in misleading conclusions about the validity of an instrument. The Bland-Altman method is the most popular method judging by the many citations of the article proposing this method. However, the number of citations does not necessarily mean that this method has been applied in agreement research. No previous study has been conducted to look into this. This is the first systematic review to identify statistical methods used to test for agreement of medical instruments. The proportion of various statistical methods found in this review will also reflect the proportion of medical instruments that have been validated using those particular methods in current clinical practice. Five electronic databases were searched between 2007 and 2009 to look for agreement studies. A total of 3,260 titles were initially identified. Only 412 titles were potentially related, and finally 210 fitted the inclusion criteria. The Bland-Altman method is the most popular method with 178 (85%) studies having used this method, followed by the correlation coefficient (27%) and means comparison (18%). Some of the inappropriate methods highlighted by Altman and Bland since the 1980s are still in use. This study finds that the Bland-Altman method is the most popular method used in agreement research. There are still inappropriate applications of statistical methods in some studies. It is important for a clinician or medical researcher to be aware of this issue because misleading conclusions from inappropriate analyses will jeopardize the quality of the evidence, which in turn will influence quality of care given to patients in the future.

Statistical Methods Used to Test for Agreement of Medical Instruments Measuring Continuous Variables in Method Comparison Studies: A Systematic Review

PubMed Central

Zaki, Rafdzah; Bulgiba, Awang; Ismail, Roshidi; Ismail, Noor Azina

2012-01-01

Background Accurate values are a must in medicine. An important parameter in determining the quality of a medical instrument is agreement with a gold standard. Various statistical methods have been used to test for agreement. Some of these methods have been shown to be inappropriate. This can result in misleading conclusions about the validity of an instrument. The Bland-Altman method is the most popular method judging by the many citations of the article proposing this method. However, the number of citations does not necessarily mean that this method has been applied in agreement research. No previous study has been conducted to look into this. This is the first systematic review to identify statistical methods used to test for agreement of medical instruments. The proportion of various statistical methods found in this review will also reflect the proportion of medical instruments that have been validated using those particular methods in current clinical practice. Methodology/Findings Five electronic databases were searched between 2007 and 2009 to look for agreement studies. A total of 3,260 titles were initially identified. Only 412 titles were potentially related, and finally 210 fitted the inclusion criteria. The Bland-Altman method is the most popular method with 178 (85%) studies having used this method, followed by the correlation coefficient (27%) and means comparison (18%). Some of the inappropriate methods highlighted by Altman and Bland since the 1980s are still in use. Conclusions This study finds that the Bland-Altman method is the most popular method used in agreement research. There are still inappropriate applications of statistical methods in some studies. It is important for a clinician or medical researcher to be aware of this issue because misleading conclusions from inappropriate analyses will jeopardize the quality of the evidence, which in turn will influence quality of care given to patients in the future. PMID:22662248

Indirect scaling methods for testing quantitative emotion theories.

PubMed

Junge, Martin; Reisenzein, Rainer

2013-01-01

Two studies investigated the utility of indirect scaling methods, based on graded pair comparisons, for the testing of quantitative emotion theories. In Study 1, we measured the intensity of relief and disappointment caused by lottery outcomes, and in Study 2, the intensity of disgust evoked by pictures, using both direct intensity ratings and graded pair comparisons. The stimuli were systematically constructed to reflect variables expected to influence the intensity of the emotions according to theoretical models of relief/disappointment and disgust, respectively. Two probabilistic scaling methods were used to estimate scale values from the pair comparison judgements: Additive functional measurement (AFM) and maximum likelihood difference scaling (MLDS). The emotion models were fitted to the direct and indirect intensity measurements using nonlinear regression (Study 1) and analysis of variance (Study 2). Both studies found substantially improved fits of the emotion models for the indirectly determined emotion intensities, with their advantage being evident particularly at the level of individual participants. The results suggest that indirect scaling methods yield more precise measurements of emotion intensity than rating scales and thereby provide stronger tests of emotion theories in general and quantitative emotion theories in particular.

Efficiency tests of samplers for microbiological aerosols, a review

NASA Technical Reports Server (NTRS)

Henningson, E.; Faengmark, I.

1984-01-01

To obtain comparable results from studies using a variety of samplers of microbiological aerosols with different collection performances for various particle sizes, methods reported in the literature were surveyed, evaluated, and tabulated for testing the efficiency of the samplers. It is concluded that these samplers were not thoroughly tested, using reliable methods. Tests were conducted in static air chambers and in various outdoor and work environments. Results are not reliable as it is difficult to achieve stable and reproducible conditions in these test systems. Testing in a wind tunnel is recommended.

A Modified Edge Crack Torsion Test for Measurement of Mode III Fracture Toughness of Laminated Tape Composites

NASA Technical Reports Server (NTRS)

Czabaj, Michael W.; Davidson, Barry D.; Ratcliffe, James G.

2016-01-01

Modifications to the edge crack torsion (ECT) test are studied to improve the reliability of this test for measuring the mode-III fracture toughness, G (sub IIIc), of laminated tape fiber-reinforced polymeric (FRP) composites. First, the data reduction methods currently used in the ECT test are evaluated and deficiencies in their accuracy are discussed. An alternative data reduction technique, which uses a polynomial form to represent ECT specimen compliance solution, is evaluated and compared to FEA (finite element analysis) results. Second, seven batches of ECT specimens are tested, each batch containing specimens with a preimplanted midplane edge delamination and midplane plies with orientations of plus theta divided by minus theta, with theta ranging from 0 degrees to 90 degrees in 15-degree increments. Tests on these specimens show that intralaminar cracking occurs in specimens from all batches except for which theta = 15 degrees and 30 degrees. Tests on specimens of these two batches are shown to result in mode-III delamination growth at the intended ply interface. The findings from this study are encouraging steps towards the use of the ECT test as a standardized method for measuring G (sub IIIc), although further modification to the data reduction method is required to make it suitable for use as part of a standardized test method.

Unified Least Squares Methods for the Evaluation of Diagnostic Tests With the Gold Standard

PubMed Central

Tang, Liansheng Larry; Yuan, Ao; Collins, John; Che, Xuan; Chan, Leighton

2017-01-01

The article proposes a unified least squares method to estimate the receiver operating characteristic (ROC) parameters for continuous and ordinal diagnostic tests, such as cancer biomarkers. The method is based on a linear model framework using the empirically estimated sensitivities and specificities as input “data.” It gives consistent estimates for regression and accuracy parameters when the underlying continuous test results are normally distributed after some monotonic transformation. The key difference between the proposed method and the method of Tang and Zhou lies in the response variable. The response variable in the latter is transformed empirical ROC curves at different thresholds. It takes on many values for continuous test results, but few values for ordinal test results. The limited number of values for the response variable makes it impractical for ordinal data. However, the response variable in the proposed method takes on many more distinct values so that the method yields valid estimates for ordinal data. Extensive simulation studies are conducted to investigate and compare the finite sample performance of the proposed method with an existing method, and the method is then used to analyze 2 real cancer diagnostic example as an illustration. PMID:28469385

Lyophilic matrix method for dissolution and release studies of nanoscale particles.

PubMed

Pessi, Jenni; Svanbäck, Sami; Lassila, Ilkka; Hæggström, Edward; Yliruusi, Jouko

2017-10-25

We introduce a system with a lyophilic matrix to aid dissolution studies of powders and particulate systems. This lyophilic matrix method (LM method) is based on the ability to discriminate between non-dissolved particles and the dissolved species. In the LM method the test substance is embedded in a thin lyophilic core-shell matrix. This permits rapid contact with the dissolution medium while minimizing dispersion of non-dissolved particles without presenting a substantial diffusion barrier. The method produces realistic dissolution and release results for particulate systems, especially those featuring nanoscale particles. By minimizing method-induced effects on the dissolution profile of nanopowders, the LM method overcomes shortcomings associated with current dissolution tests. Copyright © 2017 Elsevier B.V. All rights reserved.

HILIS - A HIGH INTENSITY LIGHT SYSTEM FOR ALGAE FOOD PRODUCTION,

DTIC Science & Technology

ALGAE, PRODUCTION CONTROL), (*FOOD, FEASIBILITY STUDIES), CHLORELLA , CALORIMETRY, NUTRITION, MODEL TESTS, ILLUMINATION, BRIGHTNESS, TEMPERATURE CONTROL, HEAT TRANSFER, SPECTRUM SIGNATURES, TEST METHODS, TEST EQUIPMENT.

The Effect of DBAE Approach on Teaching Painting of Undergraduate Art Students

ERIC Educational Resources Information Center

Hedayat, Mina; Kahn, Sabzali Musa; Honarvar, Habibeh; Bakar, Syed Alwi Syed Abu; Samsuddin, Mohd Effindi

2013-01-01

The aim of this study is to implement a new method of teaching painting which uses the Discipline-Based Art Education (DBAE) approach for the undergraduate art students at Tehran University. In the current study, the quasi-experimental method was used to test the hypothesis three times (pre, mid and post-tests). Thirty students from two classes…

Applied Chaos Level Test for Validation of Signal Conditions Underlying Optimal Performance of Voice Classification Methods

ERIC Educational Resources Information Center

Liu, Boquan; Polce, Evan; Sprott, Julien C.; Jiang, Jack J.

2018-01-01

Purpose: The purpose of this study is to introduce a chaos level test to evaluate linear and nonlinear voice type classification method performances under varying signal chaos conditions without subjective impression. Study Design: Voice signals were constructed with differing degrees of noise to model signal chaos. Within each noise power, 100…

Characterization of new eye drops with choline salicylate and assessment of their irritancy by in vitro short time exposure tests.

PubMed

Wroblewska, Katarzyna; Kucinska, Małgorzata; Murias, Marek; Lulek, Janina

2015-09-01

The aim of our study was to examine the irritation potential of new eye drops containing 2% choline salicylate (CS) as an active pharmaceutical ingredient (API) and various polymers increasing eye drop viscosity (hydroxyethylcellulose, hydroxypropyl methylcellulose, methylcellulose, polyvinyl alcohol, polyvinylpyrrolidone). The standard method for assessing the potential of irritating substances has been the Draize rabbit eye test. However the European Centre for Validation of Alternative Methods and the Coordinating Committee for Validation of Alternative Methods recommend, short time exposure (STE) in vitro tests as an alternative method for assessing eye irritation. The eye irritation potential was determined using cytotoxicity test methods for rabbit corneal cell line (SIRC) after 5 min exposure. The viability of cells was determined using two cytotoxicity assays: MTT and Neutral Red Uptake. According to the irritation rankings for the short time exposure test, all tested eye drops are classified as non-irritating (cell viability >70%).

Characterization of new eye drops with choline salicylate and assessment of their irritancy by in vitro short time exposure tests

PubMed Central

Wroblewska, Katarzyna; Kucinska, Małgorzata; Murias, Marek; Lulek, Janina

2014-01-01

The aim of our study was to examine the irritation potential of new eye drops containing 2% choline salicylate (CS) as an active pharmaceutical ingredient (API) and various polymers increasing eye drop viscosity (hydroxyethylcellulose, hydroxypropyl methylcellulose, methylcellulose, polyvinyl alcohol, polyvinylpyrrolidone). The standard method for assessing the potential of irritating substances has been the Draize rabbit eye test. However the European Centre for Validation of Alternative Methods and the Coordinating Committee for Validation of Alternative Methods recommend, short time exposure (STE) in vitro tests as an alternative method for assessing eye irritation. The eye irritation potential was determined using cytotoxicity test methods for rabbit corneal cell line (SIRC) after 5 min exposure. The viability of cells was determined using two cytotoxicity assays: MTT and Neutral Red Uptake. According to the irritation rankings for the short time exposure test, all tested eye drops are classified as non-irritating (cell viability >70%). PMID:27134543

Evaluating the dynamic response of in-flight thrust calculation techniques during throttle transients

NASA Technical Reports Server (NTRS)

Ray, Ronald J.

1994-01-01

New flight test maneuvers and analysis techniques for evaluating the dynamic response of in-flight thrust models during throttle transients have been developed and validated. The approach is based on the aircraft and engine performance relationship between thrust and drag. Two flight test maneuvers, a throttle step and a throttle frequency sweep, were developed and used in the study. Graphical analysis techniques, including a frequency domain analysis method, were also developed and evaluated. They provide quantitative and qualitative results. Four thrust calculation methods were used to demonstrate and validate the test technique. Flight test applications on two high-performance aircraft confirmed the test methods as valid and accurate. These maneuvers and analysis techniques were easy to implement and use. Flight test results indicate the analysis techniques can identify the combined effects of model error and instrumentation response limitations on the calculated thrust value. The methods developed in this report provide an accurate approach for evaluating, validating, or comparing thrust calculation methods for dynamic flight applications.

A studentized permutation test for three-arm trials in the 'gold standard' design.

PubMed

Mütze, Tobias; Konietschke, Frank; Munk, Axel; Friede, Tim

2017-03-15

The 'gold standard' design for three-arm trials refers to trials with an active control and a placebo control in addition to the experimental treatment group. This trial design is recommended when being ethically justifiable and it allows the simultaneous comparison of experimental treatment, active control, and placebo. Parametric testing methods have been studied plentifully over the past years. However, these methods often tend to be liberal or conservative when distributional assumptions are not met particularly with small sample sizes. In this article, we introduce a studentized permutation test for testing non-inferiority and superiority of the experimental treatment compared with the active control in three-arm trials in the 'gold standard' design. The performance of the studentized permutation test for finite sample sizes is assessed in a Monte Carlo simulation study under various parameter constellations. Emphasis is put on whether the studentized permutation test meets the target significance level. For comparison purposes, commonly used Wald-type tests, which do not make any distributional assumptions, are included in the simulation study. The simulation study shows that the presented studentized permutation test for assessing non-inferiority in three-arm trials in the 'gold standard' design outperforms its competitors, for instance the test based on a quasi-Poisson model, for count data. The methods discussed in this paper are implemented in the R package ThreeArmedTrials which is available on the comprehensive R archive network (CRAN). Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Ignitability test method

NASA Technical Reports Server (NTRS)

Bement, Laurence J.; Schimmel, Morry L.

1989-01-01

To overcome serious weaknesses in determining the performance of initiating devices, a novel 'ignitability test method', representing actual design interfaces and ignition materials, has been developed. Ignition device output consists of heat, light, gas an burning particles. Past research methods have evaluated these parameters individually. This paper describes the development and demonstration of an ignitability test method combining all these parameters, and the quantitative assessment of the ignition performance of two widely used percussion primers, the M42C1-PA101 and the M42C2-793. The ignition materials used for this evaluation were several powder, granule and pellet sizes of black powder and boron-potassium nitrate. This test method should be useful for performance evaluation of all initiator types, quality assurance, evaluation of ignition interfaces, and service life studies of initiators and ignition materials.

Proposal of a method for the evaluation of inaccuracy of home sphygmomanometers.

PubMed

Akpolat, Tekin

2009-10-01

There is no formal protocol for evaluating the individual accuracy of home sphygmomanometers. The aims of this study were to propose a method for achieving accuracy in automated home sphygmomanometers and to test the applicability of the defined method. The purposes of this method were to avoid major inaccuracies and to estimate the optimal circumstance for individual accuracy. The method has three stages and sequential measurement of blood pressure is used. The tested devices were categorized into four groups: accurate, acceptable, inaccurate and very inaccurate (major inaccuracy). The defined method takes approximately 10 min (excluding relaxation time) and was tested on three different occasions. The application of the method has shown that inaccuracy is a common problem among non-tested devices, that validated devices are superior to those that are non-validated or whose validation status is unknown, that major inaccuracy is common, especially in non-tested devices and that validation does not guarantee individual accuracy. A protocol addressing the accuracy of a particular sphygmomanometer in an individual patient is required, and a practical method has been suggested to achieve this. This method can be modified, but the main idea and approach should be preserved unless a better method is proposed. The purchase of validated devices and evaluation of accuracy for the purchased device in an individual patient will improve the monitoring of self-measurement of blood pressure at home. This study addresses device inaccuracy, but errors related to the patient, observer or blood pressure measurement technique should not be underestimated, and strict adherence to the manufacturer's instructions is essential.

Comparison of broth macrodilution, broth microdilution, and E test antifungal susceptibility tests for fluconazole.

PubMed Central

Sewell, D L; Pfaller, M A; Barry, A L

1994-01-01

A comparison of the E test, the broth microdilution test, and the reference broth macrodilution susceptibility test of the National Committee for Clinical Laboratory Standards for fluconazole susceptibility testing was performed with 238 clinical isolates of Candida species and Torulopsis (Candida) glabrata. An 80% inhibition endpoint MIC was determined by the reference broth macrodilution method after 48 h of incubation. The MICs obtained by the two study methods were read after 24 and 48 h of incubation. Overall, excellent agreement within 2 doubling dilutions was obtained between the broth microdilution and the broth macrodilution methods for the combined results for all species at both 24 h (93%) and 48 h (94%). The correlation of 24-h MIC endpoints between the E test and the broth macrodilution methods was 37% for T. glabrata, 56% for Candida tropicalis, 93% for Candida albicans, and 90% for other Candida species. The percent agreement at 48 h ranged from 34% for T. glabrata to 97% for Candida species other than C. albicans and C. tropicalis. These initial results support the further evaluation of the E test as an alternative method for fluconazole susceptibility testing of Candida species. PMID:7814531

Comparison of Clark's presence-absence test and the membrane filter method for coliform detection in potable water samples.

PubMed Central

Pipes, W O; Minnigh, H A; Moyer, B; Troy, M A

1986-01-01

A total of 2,601 water samples from six different water systems were tested for coliform bacteria by Clark's presence-absence (P-A) test and by the membrane filter (MF) method. There was no significant difference in the fraction of samples positive for coliform bacteria for any of the systems tested. It was concluded that the two tests are equivalent for monitoring purposes. However, 152 samples were positive for coliform bacteria by the MF method but negative by the P-A test, and 132 samples were positive by the P-A test but negative by the MF method. Many of these differences for individual samples can be explained by random dispersion of bacteria in subsamples when the coliform density is low. However, 15 samples had MF counts greater than 3 and gave negative P-A results. The only apparent explanation for most of these results is that coliform bacteria were present in the P-A test bottles but did not produce acid and gas. Two other studies have reported more samples positive by Clark's P-A test than by the MF method. PMID:3532953

Patient simulation: a literary synthesis of assessment tools in anesthesiology.

PubMed

Edler, Alice A; Fanning, Ruth G; Chen, Michael I; Claure, Rebecca; Almazan, Dondee; Struyk, Brain; Seiden, Samuel C

2009-12-20

High-fidelity patient simulation (HFPS) has been hypothesized as a modality for assessing competency of knowledge and skill in patient simulation, but uniform methods for HFPS performance assessment (PA) have not yet been completely achieved. Anesthesiology as a field founded the HFPS discipline and also leads in its PA. This project reviews the types, quality, and designated purpose of HFPS PA tools in anesthesiology. We used the systematic review method and systematically reviewed anesthesiology literature referenced in PubMed to assess the quality and reliability of available PA tools in HFPS. Of 412 articles identified, 50 met our inclusion criteria. Seventy seven percent of studies have been published since 2000; more recent studies demonstrated higher quality. Investigators reported a variety of test construction and validation methods. The most commonly reported test construction methods included "modified Delphi Techniques" for item selection, reliability measurement using inter-rater agreement, and intra-class correlations between test items or subtests. Modern test theory, in particular generalizability theory, was used in nine (18%) of studies. Test score validity has been addressed in multiple investigations and shown a significant improvement in reporting accuracy. However the assessment of predicative has been low across the majority of studies. Usability and practicality of testing occasions and tools was only anecdotally reported. To more completely comply with the gold standards for PA design, both shared experience of experts and recognition of test construction standards, including reliability and validity measurements, instrument piloting, rater training, and explicit identification of the purpose and proposed use of the assessment tool, are required.

Screening tests for hazard classification of complex waste materials - Selection of methods

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

Weltens, R., E-mail: reinhilde.weltens@vito.be; Vanermen, G.; Tirez, K.

In this study we describe the development of an alternative methodology for hazard characterization of waste materials. Such an alternative methodology for hazard assessment of complex waste materials is urgently needed, because the lack of a validated instrument leads to arbitrary hazard classification of such complex waste materials. False classification can lead to human and environmental health risks and also has important financial consequences for the waste owner. The Hazardous Waste Directive (HWD) describes the methodology for hazard classification of waste materials. For mirror entries the HWD classification is based upon the hazardous properties (H1-15) of the waste which canmore » be assessed from the hazardous properties of individual identified waste compounds or - if not all compounds are identified - from test results of hazard assessment tests performed on the waste material itself. For the latter the HWD recommends toxicity tests that were initially designed for risk assessment of chemicals in consumer products (pharmaceuticals, cosmetics, biocides, food, etc.). These tests (often using mammals) are not designed nor suitable for the hazard characterization of waste materials. With the present study we want to contribute to the development of an alternative and transparent test strategy for hazard assessment of complex wastes that is in line with the HWD principles for waste classification. It is necessary to cope with this important shortcoming in hazardous waste classification and to demonstrate that alternative methods are available that can be used for hazard assessment of waste materials. Next, by describing the pros and cons of the available methods, and by identifying the needs for additional or further development of test methods, we hope to stimulate research efforts and development in this direction. In this paper we describe promising techniques and argument on the test selection for the pilot study that we have performed on different types of waste materials. Test results are presented in a second paper. As the application of many of the proposed test methods is new in the field of waste management, the principles of the tests are described. The selected tests tackle important hazardous properties but refinement of the test battery is needed to fulfil the a priori conditions.« less

Least squares regression methods for clustered ROC data with discrete covariates.

PubMed

Tang, Liansheng Larry; Zhang, Wei; Li, Qizhai; Ye, Xuan; Chan, Leighton

2016-07-01

The receiver operating characteristic (ROC) curve is a popular tool to evaluate and compare the accuracy of diagnostic tests to distinguish the diseased group from the nondiseased group when test results from tests are continuous or ordinal. A complicated data setting occurs when multiple tests are measured on abnormal and normal locations from the same subject and the measurements are clustered within the subject. Although least squares regression methods can be used for the estimation of ROC curve from correlated data, how to develop the least squares methods to estimate the ROC curve from the clustered data has not been studied. Also, the statistical properties of the least squares methods under the clustering setting are unknown. In this article, we develop the least squares ROC methods to allow the baseline and link functions to differ, and more importantly, to accommodate clustered data with discrete covariates. The methods can generate smooth ROC curves that satisfy the inherent continuous property of the true underlying curve. The least squares methods are shown to be more efficient than the existing nonparametric ROC methods under appropriate model assumptions in simulation studies. We apply the methods to a real example in the detection of glaucomatous deterioration. We also derive the asymptotic properties of the proposed methods. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

An Empirical Comparison of Methods for Equating with Randomly Equivalent Groups of 50 to 400 Test Takers. Research Report. ETS RR-10-05

ERIC Educational Resources Information Center

Livingston, Samuel A.; Kim, Sooyeon

2010-01-01

A series of resampling studies investigated the accuracy of equating by four different methods in a random groups equating design with samples of 400, 200, 100, and 50 test takers taking each form. Six pairs of forms were constructed. Each pair was constructed by assigning items from an existing test taken by 9,000 or more test takers. The…

Diagnostic Value of Leukocyte Esterase Test Strip Reagents for Rapid Clinical Diagnosis of Spontaneous Bacterial Peritonitis in Patients Admitted to Hospital Emergency Departments in Iran.

PubMed

Hashemian, Amir Masoud; Ahmadi, Koorosh; Zamani Moghaddam, Hamid; Zakeri, Hosein; Davoodi Navakh, Seyed Akbar; Sharifi, Mohammad Davood; Bahrami, Abdollah

2015-10-01

Spontaneous bacterial peritonitis (SBP) is a common and important clinical problem and is life-threatening in decompensated liver disease. Ascites fluid test by leukocyte esterase test strip has been recently proposed as an effective and rapid method to diagnose SBP in patients with cirrhosis. This study aimed to evaluate sensitivity and specificity of leukocyte esterase test strip in the diagnosis of SBP. The population of this research was all patients with cirrhosis and ascites admitted to the emergency room at Imam Reza (AS) hospital, Mashhad. A written consent was taken for inclusion in the study. 50 mL ascites sample was taken from all patients for use in a urine test strip (LER) (Urine Test Strips Convergys®Urine Matrix 11). The patient's ascites samples were evaluated for cell counting. Positive dipstick test for LER in this study considered as grade 3 +. The values of WBC > 500 cell/mm(3) or PMN > 250 cell/mm(3) considered as positive result of the gold standard method for the diagnosis of SBP. In this study, 100 patients with ascites due to cirrhosis, with an average age of 38.9 ± 6.54 years were evaluated. Twenty cases had positive results, of whom 17 cases were also detected based on the standard diagnostic criteria and other three cases were healthy individuals. Thus, sensitivity, specificity, positive and negative predictive values, and accuracy of the method were 95%, 96.3%, 85%, 97.5% and 95%, respectively. The use of leukocyte esterase urine dipstick test can be a quick and easy method in early diagnosis of SBP to start the treatment until preparation of SBP-cell count results.

The strength of plants: theory and experimental methods to measure the mechanical properties of stems.

PubMed

Shah, Darshil U; Reynolds, Thomas P S; Ramage, Michael H

2017-07-20

From the stems of agricultural crops to the structural trunks of trees, studying the mechanical behaviour of plant stems is critical for both commerce and science. Plant scientists are also increasingly relying on mechanical test data for plant phenotyping. Yet there are neither standardized methods nor systematic reviews of current methods for the testing of herbaceous stems. We discuss the architecture of plant stems and highlight important micro- and macrostructural parameters that need to be controlled and accounted for when designing test methodologies, or that need to be understood in order to explain observed mechanical behaviour. Then, we critically evaluate various methods to test structural properties of stems, including flexural bending (two-, three-, and four-point bending) and axial loading (tensile, compressive, and buckling) tests. Recommendations are made on best practices. This review is relevant to fundamental studies exploring plant biomechanics, mechanical phenotyping of plants, and the determinants of mechanical properties in cell walls, as well as to application-focused studies, such as in agro-breeding and forest management projects, aiming to understand deformation processes of stem structures. The methods explored here can also be extended to other elongated, rod-shaped organs (e.g. petioles, midribs, and even roots). © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Interlaboratory study of a method for determining nonvolatile organic carbon in aquifer materials

USGS Publications Warehouse

Caughey, M.E.; Barcelona, M.J.; Powell, R.M.; Cahill, R.A.; Gron, C.; Lawrenz, D.; Meschi, P.L.

1995-01-01

The organic carbon fraction in aquifer materials exerts a major influence on the subsurface mobilities of organic and organic-associated contaminants. The spatial distribution of total organic carbon (TOC) in aquifer materials must be determined before the transport of hydrophobic organic pollutants in aquifers can be modeled accurately. Previous interlaboratory studies showed that it is difficult to measure TOC concentrations 1%. We have tested a new analytical method designed to improve the accuracy and precision of nonvolatile TOC quantitation in geologic materials that also contain carbonate minerals. Four authentic aquifer materials and one NIST standard reference material were selected as test materials for a blind collaborative study. Nonvolatile TOC in these materials ranged from 0.05 to 1.4%, while TIC ranged from 0.46 to 12.6%. Sample replicates were digested with sulfurous acid, dried at 40??C, and then combusted at 950??C using LECO or UIC instruments. For the three test materials that contained >2% TIC, incomplete acidification resulted in a systematic positive bias of TOC values reported by five of the six laboratories that used the test method. Participants did not have enough time to become proficient with the new method before they analyzed the test materials. A seventh laboratory successfully used an alternative method that analyzed separate liquid and solid fractions of the acidified sample residues. ?? 1995 Springer-Verlag.

Held Back: The Impact of Curricular and Pedagogical Factors on Tested Achievement in High School Mathematics

ERIC Educational Resources Information Center

Agvanian, Zara

2013-01-01

This study examined the impact of curricular factors and teaching practices on students' tested achievement in mathematics, explored the best predictors of the tested achievement, and examined differences in the tested achievement among student subgroups. The study utilized qualitative and quantitative methods and triangulated findings from…

Effects of Alternate Test Formats in Online Courses

ERIC Educational Resources Information Center

Francis, Alan

2010-01-01

The purpose of this study was to compare differences in methods of testing for two undergraduate online courses to determine the effect of alternate test formats in relation to participant grades. Specific purposes of this study were to determine whether a difference existed in student test scores between the control and treatment groups and…

Diagnostic accuracy of different caries risk assessment methods. A systematic review.

PubMed

Senneby, Anna; Mejàre, Ingegerd; Sahlin, Nils-Eric; Svensäter, Gunnel; Rohlin, Madeleine

2015-12-01

To evaluate the accuracy of different methods used to identify individuals with increased risk of developing dental coronal caries. Studies on following methods were included: previous caries experience, tests using microbiota, buffering capacity, salivary flow rate, oral hygiene, dietary habits and sociodemographic variables. QUADAS-2 was used to assess risk of bias. Sensitivity, specificity, predictive values, and likelihood ratios (LR) were calculated. Quality of evidence based on ≥3 studies of a method was rated according to GRADE. PubMed, Cochrane Library, Web of Science and reference lists of included publications were searched up to January 2015. From 5776 identified articles, 18 were included. Assessment of study quality identified methodological limitations concerning study design, test technology and reporting. No study presented low risk of bias in all domains. Three or more studies were found only for previous caries experience and salivary mutans streptococci and quality of evidence for these methods was low. Evidence regarding other methods was lacking. For previous caries experience, sensitivity ranged between 0.21 and 0.94 and specificity between 0.20 and 1. Tests using salivary mutans streptococci resulted in low sensitivity and high specificity. For children with primary teeth at baseline, pooled LR for a positive test was 3 for previous caries experience and 4 for salivary mutans streptococci, given a threshold ≥10(5) CFU/ml. Evidence on the validity of analysed methods used for caries risk assessment is limited. As methodological quality was low, there is a need to improve study design. Low validity for the analysed methods may lead to patients with increased risk not being identified, whereas some are falsely identified as being at risk. As caries risk assessment guides individualized decisions on interventions and intervals for patient recall, improved performance based on best evidence is greatly needed. Copyright © 2015 Elsevier Ltd. All rights reserved.

Optimizing the performance of Hyalella azteca in chronic toxicity tests: Results of feeding studies with various foods and feeding regimes

EPA Science Inventory

The freshwater amphipod Hyalella azteca is a common organism used for sediment toxicity testing in the United States and elsewhere. Standard methods for 10-d and 42-d toxicity tests with H. azteca were last revised and published by USEPA/ASTM in 2000. Under the methods in the man...

Optimizing the performance of the amphipod, Hyalella azteca, in chronic toxicity tests: Results of feeding studies with various foods and feeding regimes

EPA Science Inventory

The freshwater amphipod, Hyalella azteca, is a common organism used for sediment toxicity testing. Standard methods for 10-d and 42-d sediment toxicity tests with H. azteca were last revised and published by USEPA/ASTM in 2000. While Hyalella azteca methods exist for sediment tox...

A Model-Based Method for Content Validation of Automatically Generated Test Items

ERIC Educational Resources Information Center

Zhang, Xinxin; Gierl, Mark

2016-01-01

The purpose of this study is to describe a methodology to recover the item model used to generate multiple-choice test items with a novel graph theory approach. Beginning with the generated test items and working backward to recover the original item model provides a model-based method for validating the content used to automatically generate test…

Fiber Optics at the JLab CLAS12 Detector

NASA Astrophysics Data System (ADS)

Kroon, John; Giovanetti, Kevin

2008-10-01

The performance of wavelength shifting fibers, WLS, and method of coupling these fibers to extruded polystyrene scintillators are currently under study at James Madison University. These components are two of the main elements for the PCAL, preshower calorimeter, proposed as part of the 12 GeV upgrade for the CLAS detector at Jefferson Laboratory. The WLS fibers have been prepared, optically coupled to scintillator, and tested in order to determine their overall performance as a method of readout. Methods of coupling fiber to scintillator, a description of the test setup, test methods, PCAL readout performance, and fabrication recommendations will be presented.

Making Test Anxiety a Laughing Matter: A Quantitative Study

ERIC Educational Resources Information Center

Repass, Jim T.

2017-01-01

Relieving test anxiety actions range from relaxation exercises to prescription medication. Humor can be a simple method of test anxiety relief. The current study was used to determine if humor, in the form of a cartoon, placed on the splash page of an online exam improved the test scores of students who have high test anxiety. In the current…

An interlaboratory comparison of sediment elutriate preparation and toxicity test methods

EPA Science Inventory

Elutriate bioassays are among numerous methods that exist for assessing the potential toxicity of sediments in aquatic systems. In this study, interlaboratory results were compared from 96-hour Ceriodaphnia dubia and Pimephales promelas static-renewal acute toxicity tests conduct...

Comparative In Vitro Efficacy of Doripenem and Imipenem Against Multi-Drug Resistant Pseudomonas aeruginosa.

PubMed

Wali, Nadia; Mirza, Irfan Ali

2016-04-01

To compare the in vitro efficacy of doripenem and imipenem against multi-drug resistant (MDR) Pseudomonas aeruginosa from various clinical specimens. Descriptive cross-sectional study. Department of Microbiology, Armed Forces Institute of Pathology, Rawalpindi, from November 2012 to November 2013. MDR Pseudomonas aeruginosa isolates from various clinical samples were included in the study. Susceptibility of Pseudomonas aeruginosa against doripenem and imipenem was performed by E-test strip and agar dilution methods. The results were interpreted as recommended by Clinical Laboratory Standard Institute (CLSI) guidelines. The maximum number of Pseudomonas aeruginosa were isolated from pure pus and pus swabs. In vitro efficacy of doripenem was found to be more effective as compared to imipenem against MDR Pseudomonas aeruginosa with both E-test strip and agar dilution methods. Overall, p-values of 0.014 and 0.037 were observed when susceptibility patterns of doripenem and imipenem were evaluated with E-test strip and agar dilution methods. In vitro efficacy of doripenem was found to be better against MDR Pseudomonas aeruginosaas compared to imipenem when tested by both E-test and agar dilution methods.

Testing for measurement invariance and latent mean differences across methods: interesting incremental information from multitrait-multimethod studies

PubMed Central

Geiser, Christian; Burns, G. Leonard; Servera, Mateu

2014-01-01

Models of confirmatory factor analysis (CFA) are frequently applied to examine the convergent validity of scores obtained from multiple raters or methods in so-called multitrait-multimethod (MTMM) investigations. We show that interesting incremental information about method effects can be gained from including mean structures and tests of MI across methods in MTMM models. We present a modeling framework for testing MI in the first step of a CFA-MTMM analysis. We also discuss the relevance of MI in the context of four more complex CFA-MTMM models with method factors. We focus on three recently developed multiple-indicator CFA-MTMM models for structurally different methods [the correlated traits-correlated (methods – 1), latent difference, and latent means models; Geiser et al., 2014a; Pohl and Steyer, 2010; Pohl et al., 2008] and one model for interchangeable methods (Eid et al., 2008). We demonstrate that some of these models require or imply MI by definition for a proper interpretation of trait or method factors, whereas others do not, and explain why MI may or may not be required in each model. We show that in the model for interchangeable methods, testing for MI is critical for determining whether methods can truly be seen as interchangeable. We illustrate the theoretical issues in an empirical application to an MTMM study of attention deficit and hyperactivity disorder (ADHD) with mother, father, and teacher ratings as methods. PMID:25400603

A study protocol for enriching the interprofessional collaborative competency attainment survey insights.

PubMed

Jackson, Jeffrey B

2017-11-01

The following short report outlines a proposed study designed to evaluate the Interprofessional Collaborative Competency Attainment Survey and its recommended method of administration. This exploratory study seeks to determine if there is a significant difference between two methods of administration, the recommended and validated retrospective pre-test and post-test, and a traditional pre-test and post-test. If a significant difference does exist, this data will provide a means to determine the effect size of that difference. The comparison will be done using repeated measure ANOVA and the subsequent effect size will be evaluated using Cohen's d. As the retrospective design is utilised to evaluate a change in perceived competency, comparison of data from a traditional pre-test with a retrospective pre-test may provide a means for evaluation of the participants' change in understanding of the construct, and thus a more thorough picture of the forces driving changes to scores.

Nozzle Initiative Industry Advisory Committee on Standardization of Carbon-Phenolic Test Methods and Specifications

NASA Technical Reports Server (NTRS)

Bull, William B. (Compiler); Pinoli, Pat C. (Compiler); Upton, Cindy G. (Compiler); Day, Tony (Compiler); Hill, Keith (Compiler); Stone, Frank (Compiler); Hall, William B.

1994-01-01

This report is a compendium of the presentations of the 12th biannual meeting of the Industry Advisory Committee under the Solid Propulsion Integrity Program. A complete transcript of the welcoming talks is provided. Presentation outlines and overheads are included for the other sessions: SPIP Overview, Past, Current and Future Activity; Test Methods Manual and Video Tape Library; Air Force Developed Computer Aided Cure Program and SPC/TQM Experience; Magneto-Optical mapper (MOM), Joint Army/NASA program to assess composite integrity; Permeability Testing; Moisture Effusion Testing by Karl Fischer Analysis; Statistical Analysis of Acceptance Test Data; NMR Phenolic Resin Advancement; Constituent Testing Highlights on the LDC Optimization Program; Carbon Sulfur Study, Performance Related Testing; Current Rayon Specifications and Future Availability; RSRM/SPC Implementation; SRM Test Methods, Delta/Titan/FBM/RSRM; and Open Forum on Performance Based Acceptance Testing -- Industry Experience.

The effect of grinding and/or airborne-particle abrasion on the bond strength between zirconia and veneering porcelain: a systematic review

PubMed Central

Lundberg, Karin; Wu, Lindsey; Papia, Evaggelia

2017-01-01

Abstract Objective: The aim of the study was to make an inventory of current literature on the bond strength between zirconia and veneering porcelain after surface treatment of zirconia by grinding with diamond bur and/or with airborne-particle abrasion. Material and methods: The literature search for the present review was made following recommended guidelines using acknowledged methodology on how to do a systematic review. The electronic databases PubMed, Cochrane Library, and Science Direct were used in the present study. Results: Twelve studies were selected. Test methods used in the original studies included shear bond strength (SBS) test, tensile bond strength test, and micro-tensile bond strength test. The majority of studies used SBS. Results showed a large variation within each surface treatment of zirconia, using different grain size, blasting time, and pressure. Conclusions: Airborne-particle abrasion might improve the bond strength and can therefore be considered a feasible surface treatment for zirconia that is to be bonded. Grinding has been recommended as a surface treatment for zirconia to improve the bond strength; however, this recommendation cannot be verified. A standardized test method and surface treatment are required to be able to compare the results from different studies and draw further conclusions. PMID:28642927

Current status of antifungal susceptibility testing methods.

PubMed

Arikan, Sevtap

2007-11-01

Antifungal susceptibility testing is a very dynamic field of medical mycology. Standardization of in vitro susceptibility tests by the Clinical and Laboratory Standards Institute (CLSI) and the European Committee for Antimicrobial Susceptibility Testing (EUCAST), and current availability of reference methods constituted the major remarkable steps in the field. Based on the established minimum inhibitory concentration (MIC) breakpoints, it is now possible to determine the susceptibilities of Candida strains to fluconazole, itraconazole, voriconazole, and flucytosine. Moreover, utility of fluconazole antifungal susceptibility tests as an adjunct in optimizing treatment of candidiasis has now been validated. While the MIC breakpoints and clinical significance of susceptibility testing for the remaining fungi and antifungal drugs remain yet unclear, modifications of the available methods as well as other methodologies are being intensively studied to overcome the present drawbacks and limitations. Among the other methods under investigation are Etest, colorimetric microdilution, agar dilution, determination of fungicidal activity, flow cytometry, and ergosterol quantitation. Etest offers the advantage of practical application and favorable agreement rates with the reference methods that are frequently above acceptable limits. However, MIC breakpoints for Etest remain to be evaluated and established. Development of commercially available, standardized colorimetric panels that are based on CLSI method parameters has added more to the antifungal susceptibility testing armamentarium. Flow cytometry, on the other hand, appears to offer rapid susceptibility testing but requires specified equipment and further evaluation for reproducibility and standardization. Ergosterol quantitation is another novel approach, which appears potentially beneficial particularly in discrimination of azole-resistant isolates from heavy trailers. The method is yet investigational and requires to be further studied. Developments in methodology and applications of antifungal susceptibility testing will hopefully provide enhanced utility in clinical guidance of antifungal therapy. However, and particularly in immunosuppressed host, in vitro susceptibility is and will remain only one of several factors that influence clinical outcome.

Does rational selection of training and test sets improve the outcome of QSAR modeling?

PubMed

Martin, Todd M; Harten, Paul; Young, Douglas M; Muratov, Eugene N; Golbraikh, Alexander; Zhu, Hao; Tropsha, Alexander

2012-10-22

Prior to using a quantitative structure activity relationship (QSAR) model for external predictions, its predictive power should be established and validated. In the absence of a true external data set, the best way to validate the predictive ability of a model is to perform its statistical external validation. In statistical external validation, the overall data set is divided into training and test sets. Commonly, this splitting is performed using random division. Rational splitting methods can divide data sets into training and test sets in an intelligent fashion. The purpose of this study was to determine whether rational division methods lead to more predictive models compared to random division. A special data splitting procedure was used to facilitate the comparison between random and rational division methods. For each toxicity end point, the overall data set was divided into a modeling set (80% of the overall set) and an external evaluation set (20% of the overall set) using random division. The modeling set was then subdivided into a training set (80% of the modeling set) and a test set (20% of the modeling set) using rational division methods and by using random division. The Kennard-Stone, minimal test set dissimilarity, and sphere exclusion algorithms were used as the rational division methods. The hierarchical clustering, random forest, and k-nearest neighbor (kNN) methods were used to develop QSAR models based on the training sets. For kNN QSAR, multiple training and test sets were generated, and multiple QSAR models were built. The results of this study indicate that models based on rational division methods generate better statistical results for the test sets than models based on random division, but the predictive power of both types of models are comparable.

Thermal comfort of aeroplane seats: influence of different seat materials and the use of laboratory test methods.

PubMed

Bartels, Volkmar T

2003-07-01

This study determined the influence of different cover and cushion materials on the thermal comfort of aeroplane seats. Different materials as well as ready made seats were investigated by the physiological laboratory test methods Skin Model and seat comfort tester. Additionally, seat trials with human test subjects were performed in a climatic chamber. Results show that a fabric cover produces a considerably higher sweat transport than leather. A three-dimensional knitted spacer fabric turns out to be the better cushion alternative in comparison to a moulded foam pad. Results from the physiological laboratory test methods nicely correspond to the seat trials with human test subjects.

Performance Assessment of Internal Quality Control (IQC) Products in Blood Transfusion Compatibility Testing in China

PubMed Central

Li, Jing-Jing; Gao, Qi; Liu, Zhi-Dong; Kang, Qiong-Hua; Hou, Yi-Jun; Zhang, Luo-Chuan; Hu, Xiao-Mei; Li, Jie; Zhang, Juan

2015-01-01

Internal quality control (IQC) is a critical component of laboratory quality management, and IQC products can determine the reliability of testing results. In China, given the fact that most blood transfusion compatibility laboratories do not employ IQC products or do so minimally, there is a lack of uniform and standardized IQC methods. To explore the reliability of IQC products and methods, we studied 697 results from IQC samples in our laboratory from 2012 to 2014. The results showed that the sensitivity and specificity of the IQCs in anti-B testing were 100% and 99.7%, respectively. The sensitivity and specificity of the IQCs in forward blood typing, anti-A testing, irregular antibody screening, and cross-matching were all 100%. The reliability analysis indicated that 97% of anti-B testing results were at a 99% confidence level, and 99.9% of forward blood typing, anti-A testing, irregular antibody screening, and cross-matching results were at a 99% confidence level. Therefore, our IQC products and methods are highly sensitive, specific, and reliable. Our study paves the way for the establishment of a uniform and standardized IQC method for pre-transfusion compatibility testing in China and other parts of the world. PMID:26488582

New pharmacokinetic methods. III. Two simple test for deep pool effect

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

Browne, T.R.; Greenblatt, D.J.; Schumacher, G.E.

1990-08-01

If a portion of administered drug is distributed into a deep peripheral compartment, the drug's actual elimination half-life during the terminal exponential phase of elimination may be longer than determined by a single dose study or a tracer dose study (deep pool effect). Two simple methods of testing for deep pool effect applicable to drugs with either linear or nonlinear pharmacokinetic properties are described. The methods are illustrated with stable isotope labeled (13C15N2) tracer dose studies of phenytoin. No significant (P less than .05) deep pool effect was detected.

Evaluation of the Thermo Scientific SureTect Listeria species assay. AOAC Performance Tested Method 071304.

PubMed

Cloke, Jonathan; Evans, Katharine; Crabtree, David; Hughes, Annette; Simpson, Helen; Holopainen, Jani; Wickstrand, Nina; Kauppinen, Mikko; Leon-Velarde, Carlos; Larson, Nathan; Dave, Keron

2014-01-01

The Thermo Scientific SureTect Listeria species Assay is a new real-time PCR assay for the detection of all species of Listeria in food and environmental samples. This validation study was conducted using the AOAC Research Institute (RI) Performance Tested Methods program to validate the SureTect Listeria species Assay in comparison to the reference method detailed in International Organization for Standardization 11290-1:1996 including amendment 1:2004 in a variety of foods plus plastic and stainless steel. The food matrixes validated were smoked salmon, processed cheese, fresh bagged spinach, cantaloupe, cooked prawns, cooked sliced turkey meat, cooked sliced ham, salami, pork frankfurters, and raw ground beef. All matrixes were tested by Thermo Fisher Scientific, Microbiology Division, Basingstoke, UK. In addition, three matrixes (pork frankfurters, fresh bagged spinach, and stainless steel surface samples) were analyzed independently as part of the AOAC-RI-controlled independent laboratory study by the University ofGuelph, Canada. Using probability of detection statistical analysis, a significant difference in favour of the SureTect assay was demonstrated between the SureTect and reference method for high level spiked samples of pork frankfurters, smoked salmon, cooked prawns, stainless steel, and low-spiked samples of salami. For all other matrixes, no significant difference was seen between the two methods during the study. Inclusivity testing was conducted with 68 different isolates of Listeria species, all of which were detected by the SureTect Listeria species Assay. None of the 33 exclusivity isolates were detected by the SureTect Listeria species Assay. Ruggedness testing was conducted to evaluate the performance of the assay with specific method deviations outside of the recommended parameters open to variation, which demonstrated that the assay gave reliable performance. Accelerated stability testing was additionally conducted, validating the assay shelf life.

Simple, Low-Cost Data Collection Methods for Agricultural Field Studies.

ERIC Educational Resources Information Center

Koenig, Richard T.; Winger, Marlon; Kitchen, Boyd

2000-01-01

Summarizes relatively simple and inexpensive methods for collecting data from agricultural field studies. Describes methods involving on-farm testing, crop yield measurement, quality evaluations, weed control effectiveness, plant nutrient status, and other measures. Contains 29 references illustrating how these methods were used to conduct…

A Comparison of Fuzzy Models in Similarity Assessment of Misregistered Area Class Maps

NASA Astrophysics Data System (ADS)

Brown, Scott

Spatial uncertainty refers to unknown error and vagueness in geographic data. It is relevant to land change and urban growth modelers, soil and biome scientists, geological surveyors and others, who must assess thematic maps for similarity, or categorical agreement. In this paper I build upon prior map comparison research, testing the effectiveness of similarity measures on misregistered data. Though several methods compare uncertain thematic maps, few methods have been tested on misregistration. My objective is to test five map comparison methods for sensitivity to misregistration, including sub-pixel errors in both position and rotation. Methods included four fuzzy categorical models: fuzzy kappa's model, fuzzy inference, cell aggregation, and the epsilon band. The fifth method used conventional crisp classification. I applied these methods to a case study map and simulated data in two sets: a test set with misregistration error, and a control set with equivalent uniform random error. For all five methods, I used raw accuracy or the kappa statistic to measure similarity. Rough-set epsilon bands report the most similarity increase in test maps relative to control data. Conversely, the fuzzy inference model reports a decrease in test map similarity.

Grouping methods for estimating the prevalences of rare traits from complex survey data that preserve confidentiality of respondents.

PubMed

Hyun, Noorie; Gastwirth, Joseph L; Graubard, Barry I

2018-03-26

Originally, 2-stage group testing was developed for efficiently screening individuals for a disease. In response to the HIV/AIDS epidemic, 1-stage group testing was adopted for estimating prevalences of a single or multiple traits from testing groups of size q, so individuals were not tested. This paper extends the methodology of 1-stage group testing to surveys with sample weighted complex multistage-cluster designs. Sample weighted-generalized estimating equations are used to estimate the prevalences of categorical traits while accounting for the error rates inherent in the tests. Two difficulties arise when using group testing in complex samples: (1) How does one weight the results of the test on each group as the sample weights will differ among observations in the same group. Furthermore, if the sample weights are related to positivity of the diagnostic test, then group-level weighting is needed to reduce bias in the prevalence estimation; (2) How does one form groups that will allow accurate estimation of the standard errors of prevalence estimates under multistage-cluster sampling allowing for intracluster correlation of the test results. We study 5 different grouping methods to address the weighting and cluster sampling aspects of complex designed samples. Finite sample properties of the estimators of prevalences, variances, and confidence interval coverage for these grouping methods are studied using simulations. National Health and Nutrition Examination Survey data are used to illustrate the methods. Copyright © 2018 John Wiley & Sons, Ltd.

The effect of social and token economy reinforcements on academic achievement of students with intellectual disabilities.

PubMed

Mirzamani, S Mahmood; Ashoori, Mohammad; Sereshki, Narges Adib

2011-01-01

This study investigates the effect of social and token economy reinforcements on academic achievement of 9th grade boy students with intellectual disabilities in an experimental science class in Tehran Province. The method used for this study was experimental by pre-test, post- test with a control group. The boy students with intellectual disabilities from three junior high schools participated in this study. The sample consisted of thirty, 9th grade boy students with intellectual disabilities in the selected schools; the schools were chosen by the multi-stage cluster method. To measure the progress of students in the science class, a teacher made test and the Wechsler intelligence test for matching the groups for IQ were used. To ensure validity, the content validity criteria depended tests calculated by the Lashe method and teachers' perspective were used. The reliability coefficient was obtained by the reliability coefficient of related tests; the percent agreement method and the obtained data were analyzed using one-way variance analysis and Shefe prosecution test. The results showed that there was a significant increase in academic achievement of students with intellectual disabilities when using token economy than using social reinforcements compared with the control group. Also, when using social reinforcements, the academic achievement of students was more than the control group. Token economy and social reinforcements increased the academic achievement of students with intellectual disabilities in the science class; and also the effect of token economy reinforcements was more than social reinforcements on the subjects.

Evaluation of Cortez OneStep Chlamydia Rapicard™ Insta Test for the Detection of Chlamydia trachomatis in Pregnant Women at Mbare Polyclinic in Harare, Zimbabwe

PubMed Central

Stephen, Stephen; Muchaneta-Kubara, Chiwoneso Gwyneth Elizabeth; Munjoma, Marshall Wesley; Mandozana, Gibson

2017-01-01

Background: Cervical chlamydia infection poses high risk of pregnancy complications and neonatal infection. Reference methods for the detection of chlamydia infection are not available for routine use in developing countries. Point-of-care (POC) tests can bridge this gap. This study evaluated Cortez Onestep Chlamydia Rapicard™ insta test for the detection of Chlamydia trachomatis in pregnant women at Mbare Polyclinic and determined the prevalence of C. trachomatis. Methods: This was a cross sectional study in 242 pregnant women aged ≥18 years attending their first ANC visit at Mbare polyclinic in Harare, Zimbabwe. Data collection form was used to obtain demographic and predisposing factors to Chlamydia infection and two endocervical swabs were collected from each patient. One specimen was examined by the POC test at the clinic and the other by SDA method in the laboratory. Results: The sensitivity, specificity, positive and negative predictive values of the rapid kit were 71.4%, 99.6%, 90.9% and 98.3% respectively. Prevalence of C. trachomitis was 5.8% by SDA method. Conclusion and Global Health Implications: The kit’s sensitivity (71.4%) and specificity (99.6%) implies that the rapid test is an important test which needs further evaluations. The prevalence of C. trichomitis of 5.8% is comparable to studies done elsewhere in Africa. PMID:28798890

The presence-absence coliform test for monitoring drinking water quality.

PubMed Central

Rice, E W; Geldreich, E E; Read, E J

1989-01-01

The concern for improved monitoring of the sanitary quality of drinking water has prompted interest in alternative methods for the detection of total coliform bacteria. A simplified qualitative presence-absence test has been proposed as an alternate procedure for detecting coliform bacteria in potable water. In this paper data from four comparative studies were analyzed to compare the recovery of total coliform bacteria from drinking water using the presence-absence test, the multiple fermentation tube procedure, and the membrane filter technique. The four studies were of water samples taken from four different geographic areas of the United States: Hawaii, New England (Vermont and New Hampshire), Oregon, and Pennsylvania. Analysis of the results of these studies were compared, based upon the number of positive samples detected by each method. Combined recoveries showed the presence-absence test detected significantly higher numbers of samples with coliforms than either the fermentation tube or membrane filter methods, P less than 0.01. The fermentation tube procedure detected significantly more positive samples than the membrane filter technique, P less than 0.01. Based upon the analysis of the combined data base, it is clear that the presence-absence test is as sensitive as the current coliform methods for the examination of potable water. The presence-absence test offers a viable alternative to water utility companies that elect to use the frequency-of-occurrence approach for compliance monitoring. PMID:2493663

Performing a urine dipstick test with a clean-catch urine sample is an accurate screening method for urinary tract infections in young infants.

PubMed

Herreros, María Luisa; Tagarro, Alfredo; García-Pose, Araceli; Sánchez, Aida; Cañete, Alfonso; Gili, Pablo

2018-01-01

This study evaluated using urine dipstick tests with the clean-catch method to screen for urinary tract infection (UTI) in febrile infants under 90 days of age. We carried out a comparative diagnostic accuracy study of infants under 90 days old, who were studied for unexplained fever without any source, in the emergency room of a hospital in Madrid from January 2011 to January 2013. We obtained matched samples of urine using two different methods: a clean-catch, standardised stimulation technique and catheterisation collection. The results of the leucocyte esterase test and nitrite test were compared with their urine cultures. We obtained 60 pairs of matched samples. A combined analysis of leukocyte esterase and, or, nitrites yielded a sensitivity of 86% and a specificity of 80% for the diagnosis of UTIs in clean-catch samples. The sensitivity of leukocyte esterase and, or, nitrites in samples obtained by catheterisation were not statistically different to the clean-catch samples (p = 0.592). Performing urine dipstick tests using urine samples obtained by the clean-catch method was an accurate screening test for diagnosing UTIs in febrile infants of less than 90 days old. This provided a good alternative to bladder catheterisation when screening for UTIs. ©2017 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.

Field test comparison of two dermal tolerance assessment methods of hand hygiene products.

PubMed

Girard, R; Carré, E; Pires-Cronenberger, S; Bertin-Mandy, M; Favier-Bulit, M C; Coyault, C; Coudrais, S; Billard, M; Regard, A; Kerhoas, A; Valdeyron, M L; Cracco, B; Misslin, P

2008-06-01

This study aimed to compare the sensitivity and workload requirement of two dermal tolerance assessment methods of hand hygiene products, in order to select a suitable pilot testing method for field tests. An observer-rating method and a self-assessment method were compared in 12 voluntary hospital departments (autumn/winter of 2005-2006). Three test-periods of three weeks were separated by two-week intervals during which the routine products were reintroduced. The observer rating method scored dryness and irritation on four-point scales. In the self-assessment method, the user rated appearance, intactness, moisture content, and sensation on a visual analogue scale which was converted into a 10-point numerical scale. Eleven products (soaps) were tested (223/250 complete reports for observer rating, 131/251 for self-assessment). Two products were significantly less well tolerated than the routine product according to the observers, four products according to the self-assessments. There was no significant difference between the two methods when products were classified according to tolerance (Fisher's test: P=0.491). For the symptom common to both assessment methods (dryness), there is a good correlation between the two methods (Spearman's Rho: P=0.032). The workload was higher for observer rating method (288 h of observer time plus 122 h of prevention team and pharmacist time compared with 15 h of prevention team and pharmacist time for self-assessment). In conclusion, the self-assessment method was considered more suitable for pilot testing, although further time should be allocated for educational measures as the return rate of complete self-assessment forms was poor.

Susceptibility screening of hyphae-forming fungi with a new, easy, and fast inoculum preparation method.

PubMed

Schmalreck, Arno; Willinger, Birgit; Czaika, Viktor; Fegeler, Wolfgang; Becker, Karsten; Blum, Gerhard; Lass-Flörl, Cornelia

2012-12-01

In vitro susceptibility testing of clinically important fungi becomes more and more essential due to the rising number of fungal infections in patients with impaired immune system. Existing standardized microbroth dilution methods for in vitro testing of molds (CLSI, EUCAST) are not intended for routine testing. These methods are very time-consuming and dependent on sporulating of hyphomycetes. In this multicentre study, a new (independent of sporulation) inoculum preparation method (containing a mixture of vegetative cells, hyphae, and conidia) was evaluated. Minimal inhibitory concentrations (MIC) of amphotericin B, posaconazole, and voriconazole of 180 molds were determined with two different culture media (YST and RPMI 1640) according to the DIN (Deutsches Institut für Normung) microdilution assay. 24 and 48 h MIC of quality control strains, tested per each test run, prepared with the new inoculum method were in the range of DIN. YST and RPMI 1640 media showed similar MIC distributions for all molds tested. MIC readings at 48 versus 24 h yield 1 log(2) higher MIC values and more than 90 % of the MICs read at 24 and 48 h were within ± 2 log(2) dilution. MIC end point reading (log(2 MIC-RPMI 1640)-log(2 MIC-YST)) of both media demonstrated a tendency to slightly lower MICs with RPMI 1640 medium. This study reports the results of a new, time-saving, and easy-to-perform method for inoculum preparation for routine susceptibility testing that can be applied for all types of spore-/non-spore and hyphae-forming fungi.

Feasibility of supervised self-testing using an oral fluid-based HIV rapid testing method: a cross-sectional, mixed method study among pregnant women in rural India

PubMed Central

Sarkar, Archana; Mburu, Gitau; Shivkumar, Poonam Varma; Sharma, Pankhuri; Campbell, Fiona; Behera, Jagannath; Dargan, Ritu; Mishra, Surendra Kumar; Mehra, Sunil

2016-01-01

Introduction HIV self-testing can increase coverage of essential HIV services. This study aimed to establish the acceptability, concordance and feasibility of supervised HIV self-testing among pregnant women in rural India. Methods A cross-sectional, mixed methods study was conducted among 202 consenting pregnant women in a rural Indian hospital between August 2014 and January 2015. Participants were provided with instructions on how to self-test using OraQuick® HIV antibody test, and subsequently asked to self-test under supervision of a community health worker. Test results were confirmed at a government-run integrated counselling and testing centre. A questionnaire was used to obtain information on patient demographics and the ease, acceptability and difficulties of self-testing. In-depth interviews were conducted with a sub-sample of 35 participants to understand their experiences. Results In total, 202 participants performed the non-invasive, oral fluid-based, rapid test under supervision for HIV screening. Acceptance rate was 100%. Motivators for self-testing included: ease of testing (43.4%), quick results (27.3%) and non-invasive procedure (23.2%). Sensitivity and specificity were 100% for 201 tests, and one test was invalid. Concordance of test result interpretation between community health workers and participants was 98.5% with a Cohen's Kappa (k) value of k=0.566 with p<0.001 for inter-rater agreement. Although 92.6% participants reported that the instructions for the test were easy to understand, 18.7% required the assistance of a supervisor to self-test. Major themes that emerged from the qualitative interviews indicated the importance of the following factors in influencing acceptability of self-testing: clarity and accessibility of test instructions; time-efficiency and convenience of testing; non-invasiveness of the test; and fear of incorrect results. Overall, 96.5% of the participants recommended that the OraQuick® test kits should become publicly available. Conclusions Self-testing for HIV status using an oral fluid-based rapid test under the supervision of a community health worker was acceptable and feasible among pregnant women in rural India. Participants were supportive of making self-testing publicly available. Policy guidelines and implementation research are required to advance HIV self-testing for larger populations at scale. PMID:27630096

A robust method using propensity score stratification for correcting verification bias for binary tests

PubMed Central

He, Hua; McDermott, Michael P.

2012-01-01

Sensitivity and specificity are common measures of the accuracy of a diagnostic test. The usual estimators of these quantities are unbiased if data on the diagnostic test result and the true disease status are obtained from all subjects in an appropriately selected sample. In some studies, verification of the true disease status is performed only for a subset of subjects, possibly depending on the result of the diagnostic test and other characteristics of the subjects. Estimators of sensitivity and specificity based on this subset of subjects are typically biased; this is known as verification bias. Methods have been proposed to correct verification bias under the assumption that the missing data on disease status are missing at random (MAR), that is, the probability of missingness depends on the true (missing) disease status only through the test result and observed covariate information. When some of the covariates are continuous, or the number of covariates is relatively large, the existing methods require parametric models for the probability of disease or the probability of verification (given the test result and covariates), and hence are subject to model misspecification. We propose a new method for correcting verification bias based on the propensity score, defined as the predicted probability of verification given the test result and observed covariates. This is estimated separately for those with positive and negative test results. The new method classifies the verified sample into several subsamples that have homogeneous propensity scores and allows correction for verification bias. Simulation studies demonstrate that the new estimators are more robust to model misspecification than existing methods, but still perform well when the models for the probability of disease and probability of verification are correctly specified. PMID:21856650

Testing the feasibility of eliciting preferences for health states from adolescents using direct methods.

PubMed

Crump, R Trafford; Lau, Ryan; Cox, Elizabeth; Currie, Gillian; Panepinto, Julie

2018-06-22

Measuring adolescents' preferences for health states can play an important role in evaluating the delivery of pediatric healthcare. However, formal evaluation of the common direct preference elicitation methods for health states has not been done with adolescents. Therefore, the purpose of this study is to test how these methods perform in terms of their feasibility, reliability, and validity for measuring health state preferences in adolescents. This study used a web-based survey of adolescents, 18 years of age or younger, living in the United States. The survey included four health states, each comprised of six attributes. Preferences for these health states were elicited using the visual analogue scale, time trade-off, and standard gamble. The feasibility, test-retest reliability, and construct validity of each of these preference elicitation methods were tested and compared. A total of 144 participants were included in this study. Using a web-based survey format to elicit preferences for health states from adolescents was feasible. A majority of participants completed all three elicitation methods, ranked those methods as being easy, with very few requiring assistance from someone else. However, all three elicitation methods demonstrated weak test-retest reliability, with Kendall's tau-a values ranging from 0.204 to 0.402. Similarly, all three methods demonstrated poor construct validity, with 9-50% of all rankings aligning with our expectations. There were no significant differences across age groups. Using a web-based survey format to elicit preferences for health states from adolescents is feasible. However, the reliability and construct validity of the methods used to elicit these preferences when using this survey format are poor. Further research into the effects of a web-based survey approach to eliciting preferences for health states from adolescents is needed before health services researchers or pediatric clinicians widely employ these methods.

The Effect of Coordinated Teaching Method Practices on Some Motor Skills of 6-Year-Old Children

ERIC Educational Resources Information Center

Altinkok, Mustafa

2017-01-01

Purpose: This study was designed to examine the effects of Coordinated Teaching Method activities applied for 10 weeks on 6-year-old children, and to examine the effects of these activities on the development of some motor skills in children. Research Methods: The "Experimental Research Model with Pre-test and Post-test Control Group"…

Inter-lab testing of Hyalella azteca water and sediment methods: 3 Results from 10- to 42-d tests conducted with the new water-only method

EPA Science Inventory

Over the past four years, USEPA-Duluth, USGS-Columbia, the Illinois Natural History Survey, and Environment Canada have been conducting studies to refine the USEPA and ASTM International methods for conducting 10- to 42-d water or sediment toxicity exposures with the amphipod Hya...

Comparison of manual and automatic techniques for substriatal segmentation in 11C-raclopride high-resolution PET studies.

PubMed

Johansson, Jarkko; Alakurtti, Kati; Joutsa, Juho; Tohka, Jussi; Ruotsalainen, Ulla; Rinne, Juha O

2016-10-01

The striatum is the primary target in regional C-raclopride-PET studies, and despite its small volume, it contains several functional and anatomical subregions. The outcome of the quantitative dopamine receptor study using C-raclopride-PET depends heavily on the quality of the region-of-interest (ROI) definition of these subregions. The aim of this study was to evaluate subregional analysis techniques because new approaches have emerged, but have not yet been compared directly. In this paper, we compared manual ROI delineation with several automatic methods. The automatic methods used either direct clustering of the PET image or individualization of chosen brain atlases on the basis of MRI or PET image normalization. State-of-the-art normalization methods and atlases were applied, including those provided in the FreeSurfer, Statistical Parametric Mapping8, and FSL software packages. Evaluation of the automatic methods was based on voxel-wise congruity with the manual delineations and the test-retest variability and reliability of the outcome measures using data from seven healthy male participants who were scanned twice with C-raclopride-PET on the same day. The results show that both manual and automatic methods can be used to define striatal subregions. Although most of the methods performed well with respect to the test-retest variability and reliability of binding potential, the smallest average test-retest variability and SEM were obtained using a connectivity-based atlas and PET normalization (test-retest variability=4.5%, SEM=0.17). The current state-of-the-art automatic ROI methods can be considered good alternatives for subjective and laborious manual segmentation in C-raclopride-PET studies.

Adaptive Set-Based Methods for Association Testing

PubMed Central

Su, Yu-Chen; Gauderman, W. James; Kiros, Berhane; Lewinger, Juan Pablo

2017-01-01

With a typical sample size of a few thousand subjects, a single genomewide association study (GWAS) using traditional one-SNP-at-a-time methods can only detect genetic variants conferring a sizable effect on disease risk. Set-based methods, which analyze sets of SNPs jointly, can detect variants with smaller effects acting within a gene, a pathway, or other biologically relevant sets. While self-contained set-based methods (those that test sets of variants without regard to variants not in the set) are generally more powerful than competitive set-based approaches (those that rely on comparison of variants in the set of interest with variants not in the set), there is no consensus as to which self-contained methods are best. In particular, several self-contained set tests have been proposed to directly or indirectly ‘adapt’ to the a priori unknown proportion and distribution of effects of the truly associated SNPs in the set, which is a major determinant of their power. A popular adaptive set-based test is the adaptive rank truncated product (ARTP), which seeks the set of SNPs that yields the best-combined evidence of association. We compared the standard ARTP, several ARTP variations we introduced, and other adaptive methods in a comprehensive simulation study to evaluate their performance. We used permutations to assess significance for all the methods and thus provide a level playing field for comparison. We found the standard ARTP test to have the highest power across our simulations followed closely by the global model of random effects (GMRE) and a LASSO based test. PMID:26707371

Extracting laboratory test information from biomedical text

PubMed Central

Kang, Yanna Shen; Kayaalp, Mehmet

2013-01-01

Background: No previous study reported the efficacy of current natural language processing (NLP) methods for extracting laboratory test information from narrative documents. This study investigates the pathology informatics question of how accurately such information can be extracted from text with the current tools and techniques, especially machine learning and symbolic NLP methods. The study data came from a text corpus maintained by the U.S. Food and Drug Administration, containing a rich set of information on laboratory tests and test devices. Methods: The authors developed a symbolic information extraction (SIE) system to extract device and test specific information about four types of laboratory test entities: Specimens, analytes, units of measures and detection limits. They compared the performance of SIE and three prominent machine learning based NLP systems, LingPipe, GATE and BANNER, each implementing a distinct supervised machine learning method, hidden Markov models, support vector machines and conditional random fields, respectively. Results: Machine learning systems recognized laboratory test entities with moderately high recall, but low precision rates. Their recall rates were relatively higher when the number of distinct entity values (e.g., the spectrum of specimens) was very limited or when lexical morphology of the entity was distinctive (as in units of measures), yet SIE outperformed them with statistically significant margins on extracting specimen, analyte and detection limit information in both precision and F-measure. Its high recall performance was statistically significant on analyte information extraction. Conclusions: Despite its shortcomings against machine learning methods, a well-tailored symbolic system may better discern relevancy among a pile of information of the same type and may outperform a machine learning system by tapping into lexically non-local contextual information such as the document structure. PMID:24083058

MEASUREMENT OF INDOOR AIR EMISSIONS FROM DRY-PROCESS PHOTOCOPY MACHINES

EPA Science Inventory

The article provides background information on indoor air emissions from office equipment, with emphasis on dry-process photocopy machines. The test method is described in detail along with results of a study to evaluate the test method using four dry-process photocopy machines. ...

Approximations to the distribution of a test statistic in covariance structure analysis: A comprehensive study.

PubMed

Wu, Hao

2018-05-01

In structural equation modelling (SEM), a robust adjustment to the test statistic or to its reference distribution is needed when its null distribution deviates from a χ 2 distribution, which usually arises when data do not follow a multivariate normal distribution. Unfortunately, existing studies on this issue typically focus on only a few methods and neglect the majority of alternative methods in statistics. Existing simulation studies typically consider only non-normal distributions of data that either satisfy asymptotic robustness or lead to an asymptotic scaled χ 2 distribution. In this work we conduct a comprehensive study that involves both typical methods in SEM and less well-known methods from the statistics literature. We also propose the use of several novel non-normal data distributions that are qualitatively different from the non-normal distributions widely used in existing studies. We found that several under-studied methods give the best performance under specific conditions, but the Satorra-Bentler method remains the most viable method for most situations. © 2017 The British Psychological Society.

Novel scanning electron microscope bulge test technique integrated with loading function

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

Li, Chuanwei; Xie, Huimin, E-mail: liuzw@bit.edu.cn, E-mail: xiehm@mail.tsinghua.edu.cn; Liu, Zhanwei, E-mail: liuzw@bit.edu.cn, E-mail: xiehm@mail.tsinghua.edu.cn

2014-10-15

Membranes and film-on-substrate structures are critical elements for some devices in electronics industry and for Micro Electro Mechanical Systems devices. These structures are normally at the scale of micrometer or even nanometer. Thus, the measurement for the mechanical property of these membranes poses a challenge over the conventional measurements at macro-scales. In this study, a novel bulge test method is presented for the evaluation of mechanical property of micro thin membranes. Three aspects are discussed in the study: (a) A novel bulge test with a Scanning Electron Microscope system realizing the function of loading and measuring simultaneously; (b) a simplifiedmore » Digital Image Correlation method for a height measurement; and (c) an imaging distortion correction by the introduction of a scanning Moiré method. Combined with the above techniques, biaxial modulus as well as Young's modulus of the polyimide film can be determined. Besides, a standard tensile test is conducted as an auxiliary experiment to validate the feasibility of the proposed method.« less

Satellite Vibration Testing: Angle optimisation method to Reduce Overtesting

NASA Astrophysics Data System (ADS)

Knight, Charly; Remedia, Marcello; Aglietti, Guglielmo S.; Richardson, Guy

2018-06-01

Spacecraft overtesting is a long running problem, and the main focus of most attempts to reduce it has been to adjust the base vibration input (i.e. notching). Instead this paper examines testing alternatives for secondary structures (equipment) coupled to the main structure (satellite) when they are tested separately. Even if the vibration source is applied along one of the orthogonal axes at the base of the coupled system (satellite plus equipment), the dynamics of the system and potentially the interface configuration mean the vibration at the interface may not occur all along one axis much less the corresponding orthogonal axis of the base excitation. This paper proposes an alternative testing methodology in which the testing of a piece of equipment occurs at an offset angle. This Angle Optimisation method may have multiple tests but each with an altered input direction allowing for the best match between all specified equipment system responses with coupled system tests. An optimisation process that compares the calculated equipment RMS values for a range of inputs with the maximum coupled system RMS values, and is used to find the optimal testing configuration for the given parameters. A case study was performed to find the best testing angles to match the acceleration responses of the centre of mass and sum of interface forces for all three axes, as well as the von Mises stress for an element by a fastening point. The angle optimisation method resulted in RMS values and PSD responses that were much closer to the coupled system when compared with traditional testing. The optimum testing configuration resulted in an overall average error significantly smaller than the traditional method. Crucially, this case study shows that the optimum test campaign could be a single equipment level test opposed to the traditional three orthogonal direction tests.

A nonparametric smoothing method for assessing GEE models with longitudinal binary data.

PubMed

Lin, Kuo-Chin; Chen, Yi-Ju; Shyr, Yu

2008-09-30

Studies involving longitudinal binary responses are widely applied in the health and biomedical sciences research and frequently analyzed by generalized estimating equations (GEE) method. This article proposes an alternative goodness-of-fit test based on the nonparametric smoothing approach for assessing the adequacy of GEE fitted models, which can be regarded as an extension of the goodness-of-fit test of le Cessie and van Houwelingen (Biometrics 1991; 47:1267-1282). The expectation and approximate variance of the proposed test statistic are derived. The asymptotic distribution of the proposed test statistic in terms of a scaled chi-squared distribution and the power performance of the proposed test are discussed by simulation studies. The testing procedure is demonstrated by two real data. Copyright (c) 2008 John Wiley & Sons, Ltd.

Diagnostic efficacy of in vitro methods vs. skin testing in patients with inhalant allergies

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

Corey, J.P.; Liudahl, J.J.; Young, S.A.

1991-03-01

The purpose of our study was to investigate the diagnostic efficacy of two selected methods of in vitro allergy testing. Specifically, the PRIST/modified RAST I125 isotope systems and the Quantizyme/modified EAST alkaline phosphatase method were compared. The time, expense, convenience, and diagnostic efficacy of the two procedures are discussed. Special attention is given to the practicality of each method for the practicing physician.

Assessment of corrosion fatigue damage by acoustic emission and periodic proof tests

NASA Astrophysics Data System (ADS)

Mehdizadeh, P.

1976-03-01

The development of a better nondestructive inspection method for detecting corrosion fatigue damage based on acoustic emission (AE) and periodic proof testing (PPT) is studied for corrosion fatigue tests in salt water solution under tension-tension loading. It is shown that PPT combined with AE monitoring can be a sensitive method for assessing the progress of corrosion fatigue damage as the continuous AE monitoring method. The AE-PPT technique is shown to be dependent on the geometry and size of the crack relative to the test specimen. A qualitative method based on plateauing of acoustic emission counts during proof tests due to changes in the fracture mode is used to predict the remaining fatigue life up to 70% of the actual values. PPT is shown to have no adverse effect on fatigue performance in salt water.

Masonry fireplace emissions test method: Repeatability and sensitivity to fueling protocol.

PubMed

Stern, C H; Jaasma, D R; Champion, M R

1993-03-01

A test method for masonry fireplaces has been evaluated during testing on six masonry fireplace configurations. The method determines carbon monoxide and particulate matter emission rates (g/h) and factors (g/kg) and does not require weighing of the appliance to determine the timing of fuel loading.The intralaboratory repeatability of the test method has been determined from multiple tests on the six fireplaces. For the tested fireplaces, the ratio of the highest to lowest measured PM rate averaged 1.17 and in no case was greater than 1.32. The data suggest that some of the variation is due to differences in fuel properties.The influence of fueling protocol on emissions has also been studied. A modified fueling protocol, tested in large and small fireplaces, reduced CO and PM emission factors by roughly 40% and reduced CO and PM rates from 0 to 30%. For both of these fireplaces, emission rates were less sensitive to fueling protocol than emission factors.

Diagnosis of Dementia by Machine learning methods in Epidemiological studies: a pilot exploratory study from south India.

PubMed

Bhagyashree, Sheshadri Iyengar Raghavan; Nagaraj, Kiran; Prince, Martin; Fall, Caroline H D; Krishna, Murali

2018-01-01

There are limited data on the use of artificial intelligence methods for the diagnosis of dementia in epidemiological studies in low- and middle-income country (LMIC) settings. A culture and education fair battery of cognitive tests was developed and validated for population based studies in low- and middle-income countries including India by the 10/66 Dementia Research Group. We explored the machine learning methods based on the 10/66 battery of cognitive tests for the diagnosis of dementia based in a birth cohort study in South India. The data sets for 466 men and women for this study were obtained from the on-going Mysore Studies of Natal effect of Health and Ageing (MYNAH), in south India. The data sets included: demographics, performance on the 10/66 cognitive function tests, the 10/66 diagnosis of mental disorders and population based normative data for the 10/66 battery of cognitive function tests. Diagnosis of dementia from the rule based approach was compared against the 10/66 diagnosis of dementia. We have applied machine learning techniques to identify minimal number of the 10/66 cognitive function tests required for diagnosing dementia and derived an algorithm to improve the accuracy of dementia diagnosis. Of 466 subjects, 27 had 10/66 diagnosis of dementia, 19 of whom were correctly identified as having dementia by Jrip classification with 100% accuracy. This pilot exploratory study indicates that machine learning methods can help identify community dwelling older adults with 10/66 criterion diagnosis of dementia with good accuracy in a LMIC setting such as India. This should reduce the duration of the diagnostic assessment and make the process easier and quicker for clinicians, patients and will be useful for 'case' ascertainment in population based epidemiological studies.

Study of the integration of wind tunnel and computational methods for aerodynamic configurations

NASA Technical Reports Server (NTRS)

Browne, Lindsey E.; Ashby, Dale L.

1989-01-01

A study was conducted to determine the effectiveness of using a low-order panel code to estimate wind tunnel wall corrections. The corrections were found by two computations. The first computation included the test model and the surrounding wind tunnel walls, while in the second computation the wind tunnel walls were removed. The difference between the force and moment coefficients obtained by comparing these two cases allowed the determination of the wall corrections. The technique was verified by matching the test-section, wall-pressure signature from a wind tunnel test with the signature predicted by the panel code. To prove the viability of the technique, two cases were considered. The first was a two-dimensional high-lift wing with a flap that was tested in the 7- by 10-foot wind tunnel at NASA Ames Research Center. The second was a 1/32-scale model of the F/A-18 aircraft which was tested in the low-speed wind tunnel at San Diego State University. The panel code used was PMARC (Panel Method Ames Research Center). Results of this study indicate that the proposed wind tunnel wall correction method is comparable to other methods and that it also inherently includes the corrections due to model blockage and wing lift.

The effectiveness of constructivist science instructional methods on middle school students' student achievement and motivation

NASA Astrophysics Data System (ADS)

Brooks, John

A problem facing science educators is determining the most effective means of science instruction so that students will meet or exceed the new rigorous standards. The theoretical framework for this study was based on reform and research efforts that have informed science teachers that using constructivism is the best method of science instruction. The purpose of this study was to investigate how the constructivist method of science instruction affected student achievement and student motivation in a sixth grade science classroom. The guiding research question involved understanding which method of science instruction would be most effective at improving student achievement in science. Other sub-questions included the factors that contribute to student motivation in science and the method of science instruction students receive that affects motivation to learn science. Quantitative data were collected using a pre-test and post-test single group design. T-test and ANCOVA were used to test quantitative hypotheses. Qualitative data were collected using student reflective journals and classroom discussions. Students' perspectives were transcribed, coded and used to further inform quantitative findings. The findings of this study supported the recommendations made by science reformists that the best method of science instruction was a constructivist method. This study also found that participant comments favored constructivist taught classes. The implications for social change at the local level included potential increases in student achievement in science and possibly increased understanding that can facilitate similar changes at other schools. From a global perspective, constructivist-oriented methods might result in students becoming more interested in majoring in science at the college level and in becoming part of a scientifically literate work force.

The choice of statistical methods for comparisons of dosimetric data in radiotherapy.

PubMed

Chaikh, Abdulhamid; Giraud, Jean-Yves; Perrin, Emmanuel; Bresciani, Jean-Pierre; Balosso, Jacques

2014-09-18

Novel irradiation techniques are continuously introduced in radiotherapy to optimize the accuracy, the security and the clinical outcome of treatments. These changes could raise the question of discontinuity in dosimetric presentation and the subsequent need for practice adjustments in case of significant modifications. This study proposes a comprehensive approach to compare different techniques and tests whether their respective dose calculation algorithms give rise to statistically significant differences in the treatment doses for the patient. Statistical investigation principles are presented in the framework of a clinical example based on 62 fields of radiotherapy for lung cancer. The delivered doses in monitor units were calculated using three different dose calculation methods: the reference method accounts the dose without tissues density corrections using Pencil Beam Convolution (PBC) algorithm, whereas new methods calculate the dose with tissues density correction for 1D and 3D using Modified Batho (MB) method and Equivalent Tissue air ratio (ETAR) method, respectively. The normality of the data and the homogeneity of variance between groups were tested using Shapiro-Wilks and Levene test, respectively, then non-parametric statistical tests were performed. Specifically, the dose means estimated by the different calculation methods were compared using Friedman's test and Wilcoxon signed-rank test. In addition, the correlation between the doses calculated by the three methods was assessed using Spearman's rank and Kendall's rank tests. The Friedman's test showed a significant effect on the calculation method for the delivered dose of lung cancer patients (p <0.001). The density correction methods yielded to lower doses as compared to PBC by on average (-5 ± 4.4 SD) for MB and (-4.7 ± 5 SD) for ETAR. Post-hoc Wilcoxon signed-rank test of paired comparisons indicated that the delivered dose was significantly reduced using density-corrected methods as compared to the reference method. Spearman's and Kendall's rank tests indicated a positive correlation between the doses calculated with the different methods. This paper illustrates and justifies the use of statistical tests and graphical representations for dosimetric comparisons in radiotherapy. The statistical analysis shows the significance of dose differences resulting from two or more techniques in radiotherapy.

Detecting a Weak Association by Testing its Multiple Perturbations: a Data Mining Approach

NASA Astrophysics Data System (ADS)

Lo, Min-Tzu; Lee, Wen-Chung

2014-05-01

Many risk factors/interventions in epidemiologic/biomedical studies are of minuscule effects. To detect such weak associations, one needs a study with a very large sample size (the number of subjects, n). The n of a study can be increased but unfortunately only to an extent. Here, we propose a novel method which hinges on increasing sample size in a different direction-the total number of variables (p). We construct a p-based `multiple perturbation test', and conduct power calculations and computer simulations to show that it can achieve a very high power to detect weak associations when p can be made very large. As a demonstration, we apply the method to analyze a genome-wide association study on age-related macular degeneration and identify two novel genetic variants that are significantly associated with the disease. The p-based method may set a stage for a new paradigm of statistical tests.

Detection of BRAF V600 Mutations in Melanoma: Evaluation of Concordance between the Cobas® 4800 BRAF V600 Mutation Test and the Methods Used in French National Cancer Institute (INCa) Platforms in a Real-Life Setting

PubMed Central

Mourah, Samia; Denis, Marc G.; Narducci, Fabienne Escande; Solassol, Jérôme; Merlin, Jean-Louis; Sabourin, Jean-Christophe; Scoazec, Jean-Yves; Ouafik, L’Houcine; Emile, Jean-François; Heller, Remy; Souvignet, Claude; Bergougnoux, Loïc; Merlio, Jean-Philippe

2015-01-01

Vemurafenib is approved for the treatment of metastatic melanoma in patients with BRAF V600 mutation. In pivotal clinical trials, BRAF testing has always been done with the approved cobas 4800 BRAF test. In routine practice, several methods are available and are used according to the laboratories usual procedures. A national, multicenter, non-interventional study was conducted with prospective and consecutive collection of tumor samples. A parallel evaluation was performed in routine practice between the cobas 4800 BRAF V600 mutation test and home brew methods (HBMs) of 12 national laboratories, labelled and funded by the French National Cancer Institute (INCa). For 420 melanoma samples tested, the cobas method versus HBM showed a high concordance (93.3%; kappa = 0.86) in BRAF V600 genotyping with similar mutation rates (34.0% versus 35.7%, respectively). Overall, 97.4% and 98.6% of samples gave valid results using the cobas and HBM, respectively. Of the 185 samples strictly fulfilling the cobas guidelines, the concordance rate was even higher (95.7%; kappa = 0.91; 95%CI [0.85; 0.97]). Out of the 420 samples tested, 28 (6.7%) showed discordance between HBM and cobas. This prospective study shows a high concordance rate between the cobas 4800 BRAF V600 test and home brew methods in the routine detection of BRAF V600E mutations. PMID:25789737

Thin layer chromatographic method for the detection of uric acid: collaborative study.

PubMed

Thrasher, J J; Abadie, A

1978-07-01

A collaborative study has been completed on an improved method for the detection and confirmation of uric acid from bird and insect excreta. The proposed method involves the lithium carbonate solubilization of the suspect excreta material, followed by butanol-methanol-water-acetic acid thin layer chromatography, and trisodium phosphate-phosphotungstic acid color development. The collaborative tests resulted in 100% detection of uric acid standard at the 50 ng level and 75% detection at the 20-25 ng level. No false positives were reported during tests of compounds similar to uric acid. The proposed method has been adopted official first action; the present official final action method, 44.161, will be retained for screening purposes.

Effects of Project, Inquiry and Lecture-Demonstration Teaching Methods on Senior Secondary Students' Achievement in Separation of Mixtures Practical Test

ERIC Educational Resources Information Center

Sola, Agboola Omowunmi; Ojo, Oloyede Ezekiel

2007-01-01

This study assessed and compared the relative effectiveness of three methods for teaching and conducting experiments in separation of mixtures in chemistry. A pre-test, post-test experimental design with a control group was used. Two hundred and thirty three randomly selected Senior Secondary School I (SSS I) chemistry students were drawn from…

Attitudes about Advances in Sweat Patch Testing in Drug Courts: Insights from a Case Study in Southern California

ERIC Educational Resources Information Center

Polzer, Katherine

2010-01-01

Drug courts are reinventing the drug testing framework by experimenting with new methods, including use of the sweat patch. The sweat patch is a band-aid like strip used to monitor drug court participants. The validity and reliability of the sweat patch as an effective testing method was examined, as well as the effectiveness, meaning how likely…

Results of a Test and Win Contest to Raise Radon Awareness in Urban and Rural Settings

ERIC Educational Resources Information Center

Hahn, Ellen J.; Rayens, Mary Kay; Kercsmar, Sarah E.; Robertson, Heather; Adkins, Sarah M.

2014-01-01

Background: Radon is a leading cause of lung cancer, but few test their homes to determine radon levels. Purpose: The study assessed feasibility and success of a Test and Win Contest to promote radon testing in rural and urban communities. Methods: The prospective, quasi-experimental study tested a novel contest to raise radon awareness. Paid and…

Acceptability of using electronic vending machines to deliver oral rapid HIV self-testing kits: a qualitative study.

PubMed

Young, Sean D; Daniels, Joseph; Chiu, ChingChe J; Bolan, Robert K; Flynn, Risa P; Kwok, Justin; Klausner, Jeffrey D

2014-01-01

Rates of unrecognized HIV infection are significantly higher among Latino and Black men who have sex with men (MSM). Policy makers have proposed that HIV self-testing kits and new methods for delivering self-testing could improve testing uptake among minority MSM. This study sought to conduct qualitative assessments with MSM of color to determine the acceptability of using electronic vending machines to dispense HIV self-testing kits. African American and Latino MSM were recruited using a participant pool from an existing HIV prevention trial on Facebook. If participants expressed interest in using a vending machine to receive an HIV self-testing kit, they were emailed a 4-digit personal identification number (PIN) code to retrieve the test from the machine. We followed up with those who had tested to assess their willingness to participate in an interview about their experience. Twelve kits were dispensed and 8 interviews were conducted. In general, participants expressed that the vending machine was an acceptable HIV test delivery method due to its novelty and convenience. Acceptability of this delivery model for HIV testing kits was closely associated with three main factors: credibility, confidentiality, and convenience. Future research is needed to address issues, such as user-induced errors and costs, before scaling up the dispensing method.

A study of compositional verification based IMA integration method

NASA Astrophysics Data System (ADS)

Huang, Hui; Zhang, Guoquan; Xu, Wanmeng

2018-03-01

The rapid development of avionics systems is driving the application of integrated modular avionics (IMA) systems. But meanwhile it is improving avionics system integration, complexity of system test. Then we need simplify the method of IMA system test. The IMA system supports a module platform that runs multiple applications, and shares processing resources. Compared with federated avionics system, IMA system is difficult to isolate failure. Therefore, IMA system verification will face the critical problem is how to test shared resources of multiple application. For a simple avionics system, traditional test methods are easily realizing to test a whole system. But for a complex system, it is hard completed to totally test a huge and integrated avionics system. Then this paper provides using compositional-verification theory in IMA system test, so that reducing processes of test and improving efficiency, consequently economizing costs of IMA system integration.

Moles: Tool-Assisted Environment Isolation with Closures

NASA Astrophysics Data System (ADS)

de Halleux, Jonathan; Tillmann, Nikolai

Isolating test cases from environment dependencies is often desirable, as it increases test reliability and reduces test execution time. However, code that calls non-virtual methods or consumes sealed classes is often impossible to test in isolation. Moles is a new lightweight framework which addresses this problem. For any .NET method, Moles allows test-code to provide alternative implementations, given as .NET delegates, for which C# provides very concise syntax while capturing local variables in a closure object. Using code instrumentation, the Moles framework will redirect calls to provided delegates instead of the original methods. The Moles framework is designed to work together with the dynamic symbolic execution tool Pex to enable automated test generation. In a case study, testing code programmed against the Microsoft SharePoint Foundation API, we achieved full code coverage while running tests in isolation without an actual SharePoint server. The Moles framework integrates with .NET and Visual Studio.

A SAS macro for testing differences among three or more independent groups using Kruskal-Wallis and Nemenyi tests.

PubMed

Liu, Yuewei; Chen, Weihong

2012-02-01

As a nonparametric method, the Kruskal-Wallis test is widely used to compare three or more independent groups when an ordinal or interval level of data is available, especially when the assumptions of analysis of variance (ANOVA) are not met. If the Kruskal-Wallis statistic is statistically significant, Nemenyi test is an alternative method for further pairwise multiple comparisons to locate the source of significance. Unfortunately, most popular statistical packages do not integrate the Nemenyi test, which is not easy to be calculated by hand. We described the theory and applications of the Kruskal-Wallis and Nemenyi tests, and presented a flexible SAS macro to implement the two tests. The SAS macro was demonstrated by two examples from our cohort study in occupational epidemiology. It provides a useful tool for SAS users to test the differences among three or more independent groups using a nonparametric method.

Correlation of Simulation Examination to Written Test Scores for Advanced Cardiac Life Support Testing: Prospective Cohort Study.

PubMed

Strom, Suzanne L; Anderson, Craig L; Yang, Luanna; Canales, Cecilia; Amin, Alpesh; Lotfipour, Shahram; McCoy, C Eric; Osborn, Megan Boysen; Langdorf, Mark I

2015-11-01

Traditional Advanced Cardiac Life Support (ACLS) courses are evaluated using written multiple-choice tests. High-fidelity simulation is a widely used adjunct to didactic content, and has been used in many specialties as a training resource as well as an evaluative tool. There are no data to our knowledge that compare simulation examination scores with written test scores for ACLS courses. To compare and correlate a novel high-fidelity simulation-based evaluation with traditional written testing for senior medical students in an ACLS course. We performed a prospective cohort study to determine the correlation between simulation-based evaluation and traditional written testing in a medical school simulation center. Students were tested on a standard acute coronary syndrome/ventricular fibrillation cardiac arrest scenario. Our primary outcome measure was correlation of exam results for 19 volunteer fourth-year medical students after a 32-hour ACLS-based Resuscitation Boot Camp course. Our secondary outcome was comparison of simulation-based vs. written outcome scores. The composite average score on the written evaluation was substantially higher (93.6%) than the simulation performance score (81.3%, absolute difference 12.3%, 95% CI [10.6-14.0%], p<0.00005). We found a statistically significant moderate correlation between simulation scenario test performance and traditional written testing (Pearson r=0.48, p=0.04), validating the new evaluation method. Simulation-based ACLS evaluation methods correlate with traditional written testing and demonstrate resuscitation knowledge and skills. Simulation may be a more discriminating and challenging testing method, as students scored higher on written evaluation methods compared to simulation.

Does Subjective Rating Reflect Behavioural Coding? Personality in 2 Month-Old Dog Puppies: An Open-Field Test and Adjective-Based Questionnaire.

PubMed

Barnard, Shanis; Marshall-Pescini, Sarah; Passalacqua, Chiara; Beghelli, Valentina; Capra, Alexa; Normando, Simona; Pelosi, Annalisa; Valsecchi, Paola

2016-01-01

A number of studies have recently investigated personality traits in non-human species, with the dog gaining popularity as a subject species for research in this area. Recent research has shown the consistency of personality traits across both context and time for adult dogs, both when using questionnaire based methods of investigation and behavioural analyses of the dogs' behaviour. However, only a few studies have assessed the correspondence between these two methods, with results varying considerably across studies. Furthermore, most studies have focused on adult dogs, despite the fact that an understanding of personality traits in young puppies may be important for research focusing on the genetic basis of personality traits. In the current study, we sought to evaluate the correspondence between a questionnaire based method and the in depth analyses of the behaviour of 2-month old puppies in an open-field test in which a number of both social and non-social stimuli were presented to the subjects. We further evaluated consistency of traits over time by re-testing a subset of puppies. The correspondence between methods was high and test- retest consistency (for the main trait) was also good using both evaluation methods. Results showed clear factors referring to the two main personality traits 'extroversion,' (i.e. the enthusiastic, exuberant approach to the stimuli) and 'neuroticism,' (i.e. the more cautious and fearful approach to the stimuli), potentially similar to the shyness-boldness dimension found in previous studies. Furthermore, both methods identified an 'amicability' dimension, expressing the positive interactions the pups directed at the humans stranger, and a 'reservedness' dimension which identified pups who largely chose not to interact with the stimuli, and were defined as quiet and not nosey in the questionnaire.

Application of Rapid Prototyping Methods to High-Speed Wind Tunnel Testing

NASA Technical Reports Server (NTRS)

Springer, A. M.

1998-01-01

This study was undertaken in MSFC's 14-Inch Trisonic Wind Tunnel to determine if rapid prototyping methods could be used in the design and manufacturing of high speed wind tunnel models in direct testing applications, and if these methods would reduce model design/fabrication time and cost while providing models of high enough fidelity to provide adequate aerodynamic data, and of sufficient strength to survive the test environment. Rapid prototyping methods utilized to construct wind tunnel models in a wing-body-tail configuration were: fused deposition method using both ABS plastic and PEEK as building materials, stereolithography using the photopolymer SL-5170, selective laser sintering using glass reinforced nylon, and laminated object manufacturing using plastic reinforced with glass and 'paper'. This study revealed good agreement between the SLA model, the metal model with an FDM-ABS nose, an SLA nose, and the metal model for most operating conditions, while the FDM-ABS data diverged at higher loading conditions. Data from the initial SLS model showed poor agreement due to problems in post-processing, resulting in a different configuration. A second SLS model was tested and showed relatively good agreement. It can be concluded that rapid prototyping models show promise in preliminary aerodynamic development studies at subsonic, transonic, and supersonic speeds.

Shuttle crew escape systems test conducted in JSC Bldg 9A CCT

NASA Image and Video Library

1987-03-20

Shuttle crew escape systems test is conducted by astronauts Steven R. Nagel (left) and Manley L. (Sonny) Carter in JSC One Gravity Mockup and Training Facilities Bldg 9A crew compartment trainer (CCT). Nagel and Carter are evaluating methods for crew escape during Space Shuttle controlled gliding flight. JSC test was done in advance of tests scheduled for facilities in California and Utah. Here, Carter serves as test subject evaluating egress positioning for the tractor rocket escape method - one of the two systems currently being closely studied by NASA.

Atomization and Mixing Study

NASA Technical Reports Server (NTRS)

Ferrenberg, A.; Hunt, K.; Duesberg, J.

1985-01-01

The primary objective was the obtainment of atomization and mixing performance data for a variety of typical liquid oxygen/hydrocarbon injector element designs. Such data are required to establish injector design criteria and to provide critical inputs to liquid rocket engine combustor performance and stability analysis, and computational codes and methods. Deficiencies and problems with the atomization test equipment were identified, and action initiated to resolve them. Test results of the gas/liquid mixing tests indicated that an assessment of test methods was required. A series of 71 liquid/liquid tests were performed.

Nondestructive Testing Residual Stress Using Ultrasonic Critical Refracted Longitudinal Wave

NASA Astrophysics Data System (ADS)

Xu, Chunguang; Song, Wentao; Pan, Qinxue; Li, Huanxin; Liu, Shuai

Residual stress has significant impacts on the performance of the mechanical components, especially on its strength, fatigue life and corrosion resistance and dimensional stability. Based on theory of acoustoelasticity, the testing principle of ultrasonic LCR wave method is analyzed. The testing system of residual stress is build. The method of calibration of stress coefficient is proposed in order to improve the detection precision. At last, through experiments and applications on residual stress testing of oil pipeline weld joint, vehicle's torsion shaft, glass and ceramics, gear tooth root, and so on, the result show that it deserved to be studied deeply on application and popularization of ultrasonic LCR wave method.

Longitudinal Multistage Testing

ERIC Educational Resources Information Center

Pohl, Steffi

2013-01-01

This article introduces longitudinal multistage testing (lMST), a special form of multistage testing (MST), as a method for adaptive testing in longitudinal large-scale studies. In lMST designs, test forms of different difficulty levels are used, whereas the values on a pretest determine the routing to these test forms. Since lMST allows for…

A novel in chemico method to detect skin sensitizers in highly diluted reaction conditions.

PubMed

Yamamoto, Yusuke; Tahara, Haruna; Usami, Ryota; Kasahara, Toshihiko; Jimbo, Yoshihiro; Hioki, Takanori; Fujita, Masaharu

2015-11-01

The direct peptide reactivity assay (DPRA) is a simple and versatile alternative method for the evaluation of skin sensitization that involves the reaction of test chemicals with two peptides. However, this method requires concentrated solutions of test chemicals, and hydrophobic substances may not dissolve at the concentrations required. Furthermore, hydrophobic test chemicals may precipitate when added to the reaction solution. We previously established a high-sensitivity method, the amino acid derivative reactivity assay (ADRA). This method uses novel cysteine (NAC) and novel lysine derivatives (NAL), which were synthesized by introducing a naphthalene ring to the amine group of cysteine and lysine residues. In this study, we modified the ADRA method by reducing the concentration of the test chemicals 100-fold. We investigated the accuracy of skin sensitization predictions made using the modified method, which was designated the ADRA-dilutional method (ADRA-DM). The predictive accuracy of the ADRA-DM for skin sensitization was 90% for 82 test chemicals which were also evaluated via the ADRA, and the predictive accuracy in the ADRA-DM was higher than that in the ADRA and DPRA. Furthermore, no precipitation of test compounds was observed at the initiation of the ADRA-DM reaction. These results show that the ADRA-DM allowed the use of test chemicals at concentrations two orders of magnitude lower than that possible with the ADRA. In addition, ADRA-DM does not have the restrictions on test compound solubility that were a major problem with the DPRA. Therefore, the ADRA-DM is a versatile and useful method. Copyright © 2015 John Wiley & Sons, Ltd.

Shuttle filter study. Volume 2: Contaminant generation and sensitivity studies

NASA Technical Reports Server (NTRS)

1974-01-01

Contaminant generation studies were conducted at the component level using two different methods, radioactive tracer technique and gravimetric analysis test procedure. Both of these were reduced to practice during this program. In the first of these methods, radioactively tagged components typical of those used in spacecraft were studied to determine their contaminant generation characteristics under simulated operating conditions. Because the purpose of the work was: (1) to determine the types and quantities of contaminants generated; and (2) to evaluate improved monitoring and detection schemes, no attempt was made to evaluate or qualify specific components. The components used in this test program were therefore not flight hardware items. Some of them had been used in previous tests; some were obsolete; one was an experimental device. In addition to the component tests, various materials of interest to contaminant and filtration studies were irradiated and evaluated for use as autotracer materials. These included test dusts, plastics, valve seat materials, and bearing cage materials.

Experimental Investigations on Subsequent Yield Surface of Pure Copper by Single-Sample and Multi-Sample Methods under Various Pre-Deformation.

PubMed

Liu, Gui-Long; Huang, Shi-Hong; Shi, Che-Si; Zeng, Bin; Zhang, Ke-Shi; Zhong, Xian-Ci

2018-02-10

Using copper thin-walled tubular specimens, the subsequent yield surfaces under pre-tension, pre-torsion and pre-combined tension-torsion are measured, where the single-sample and multi-sample methods are applied respectively to determine the yield stresses at specified offset strain. The rule and characteristics of the evolution of the subsequent yield surface are investigated. Under the conditions of different pre-strains, the influence of test point number, test sequence and specified offset strain on the measurement of subsequent yield surface and the concave phenomenon for measured yield surface are studied. Moreover, the feasibility and validity of the two methods are compared. The main conclusions are drawn as follows: (1) For the single or multi-sample method, the measured subsequent yield surfaces are remarkably different from cylindrical yield surfaces proposed by the classical plasticity theory; (2) there are apparent differences between the test results from the two kinds of methods: the multi-sample method is not influenced by the number of test points, test order and the cumulative effect of residual plastic strain resulting from the other test point, while those are very influential in the single-sample method; and (3) the measured subsequent yield surface may appear concave, which can be transformed to convex for single-sample method by changing the test sequence. However, for the multiple-sample method, the concave phenomenon will disappear when a larger offset strain is specified.

New decision criteria for selecting delta check methods based on the ratio of the delta difference to the width of the reference range can be generally applicable for each clinical chemistry test item.

PubMed

Park, Sang Hyuk; Kim, So-Young; Lee, Woochang; Chun, Sail; Min, Won-Ki

2012-09-01

Many laboratories use 4 delta check methods: delta difference, delta percent change, rate difference, and rate percent change. However, guidelines regarding decision criteria for selecting delta check methods have not yet been provided. We present new decision criteria for selecting delta check methods for each clinical chemistry test item. We collected 811,920 and 669,750 paired (present and previous) test results for 27 clinical chemistry test items from inpatients and outpatients, respectively. We devised new decision criteria for the selection of delta check methods based on the ratio of the delta difference to the width of the reference range (DD/RR). Delta check methods based on these criteria were compared with those based on the CV% of the absolute delta difference (ADD) as well as those reported in 2 previous studies. The delta check methods suggested by new decision criteria based on the DD/RR ratio corresponded well with those based on the CV% of the ADD except for only 2 items each in inpatients and outpatients. Delta check methods based on the DD/RR ratio also corresponded with those suggested in the 2 previous studies, except for 1 and 7 items in inpatients and outpatients, respectively. The DD/RR method appears to yield more feasible and intuitive selection criteria and can easily explain changes in the results by reflecting both the biological variation of the test item and the clinical characteristics of patients in each laboratory. We suggest this as a measure to determine delta check methods.

Experimental Study on Welded Headed Studs Used In Steel Plate-Concrete Composite Structures Compared with Contactless Method of Measuring Displacement

NASA Astrophysics Data System (ADS)

Kisała, Dawid; Tekieli, Marcin

2017-10-01

Steel plate-concrete composite structures are a new innovative design concept in which a thin steel plate is attached to the reinforced concrete beam by means of welded headed studs. The comparison between experimental studies and theoretical analysis of this type of structures shows that their behaviour is dependent on the load-slip relationship of the shear connectors used to ensure sufficient bond between the concrete and steel parts of the structure. The aim of this paper is to describe an experimental study on headed studs used in steel plate-concrete composite structures. Push-out tests were carried out to investigate the behaviour of shear connectors. The test specimens were prepared according to standard push-out tests, however, instead of I-beam, a steel plate 16 mm thick was used to better reflect the conditions in the real structure. The test specimens were produced in two batches using concrete with significantly different compressive strength. The experimental study was carried out on twelve specimens. Besides the traditional measurements based on LVDT sensors, optical measurements based on the digital image correlation method (DIC) and pattern tracking methods were used. DIC is a full-field contactless optical method for measuring displacements in experimental testing, based on the correlation of the digital images taken during test execution. With respect to conventional methods, optical measurements offer a wider scope of results and can give more information about the material or construction behaviour during the test. The ultimate load capacity and load-slip curves obtained from the experiments were compared with the values calculated based on Eurocodes, American and Chinese design specifications. It was observed that the use of the relationships developed for the traditional steel-concrete composite structures is justified in the case of ultimate load capacity of shear connectors in steel plate-concrete composite structures.

37: COMPARISON OF TWO METHODS: TBL-BASED AND LECTURE-BASED LEARNING IN NURSING CARE OF PATIENTS WITH DIABETES IN NURSING STUDENTS

PubMed Central

Khodaveisi, Masoud; Qaderian, Khosro; Oshvandi, Khodayar; Soltanian, Ali Reza; Vardanjani, Mehdi molavi

2017-01-01

Background and aims learning plays an important role in developing nursing skills and right care-taking. The Present study aims to evaluate two learning methods based on team –based learning and lecture-based learning in learning care-taking of patients with diabetes in nursing students. Method In this quasi-experimental study, 64 students in term 4 in nursing college of Bukan and Miandoab were included in the study based on knowledge and performance questionnaire including 15 questions based on knowledge and 5 questions based on performance on care-taking in patients with diabetes were used as data collection tool whose reliability was confirmed by cronbach alpha (r=0.83) by the researcher. To compare the mean score of knowledge and performance in each group in pre-test step and post-test step, pair –t test and to compare mean of scores in two groups of control and intervention, the independent t- test was used. Results There was not significant statistical difference between two groups in pre terms of knowledge and performance score (p=0.784). There was significant difference between the mean of knowledge scores and diabetes performance in the post-test in the team-based learning group and lecture-based learning group (p=0.001). There was significant difference between the mean score of knowledge of diabetes care in pre-test and post-test in base learning groups (p=0.001). Conclusion In both methods team-based and lecture-based learning approaches resulted in improvement in learning in students, but the rate of learning in the team-based learning approach is greater compared to that of lecture-based learning and it is recommended that this method be used as a higher education method in the education of students.

Implementation of Testing Equipment for Asphalt Materials : Tech Summary

DOT National Transportation Integrated Search

2009-05-01

Three new automated methods for related asphalt material and mixture testing were evaluated under this study. Each of these devices is designed to reduce testing time considerably and reduce operator error by automating the testing process. The Thery...

Implementation of testing equipment for asphalt materials : tech summary.

DOT National Transportation Integrated Search

2009-05-01

Three new automated methods for related asphalt material and mixture testing were evaluated : under this study. Each of these devices is designed to reduce testing time considerably and reduce : operator error by automating the testing process. The T...

Terahertz Imaging and Backscatter Radiography Probability of Detection Study for Space Shuttle Foam Inspections

NASA Technical Reports Server (NTRS)

Ussery, Warren; Johnson, Kenneth; Walker, James; Rummel, Ward

2008-01-01

This slide presentation reviews the use of terahertz imaging and Backscatter Radiography in a probability of detection study of the foam on the external tank (ET) shedding and damaging the shuttle orbiter. Non-destructive Examination (NDE) is performed as one method of preventing critical foam debris during the launch. Conventional NDE methods for inspection of the foam are assessed and the deficiencies are reviewed. Two methods for NDE inspection are reviewed: Backscatter Radiography (BSX) and Terahertz (THZ) Imaging. The purpose of the Probability of Detection (POD) study was to assess performance and reliability of the use of BSX and or THZ as an appropriate NDE method. The study used a test article with inserted defects, and a sample of blanks included to test for false positives. The results of the POD study are reported.

Detection of fatigue cracks by nondestructive testing methods

NASA Technical Reports Server (NTRS)

Anderson, R. T.; Delacy, T. J.; Stewart, R. C.

1973-01-01

The effectiveness was assessed of various NDT methods to detect small tight cracks by randomly introducing fatigue cracks into aluminum sheets. The study included optimizing NDT methods calibrating NDT equipment with fatigue cracked standards, and evaluating a number of cracked specimens by the optimized NDT methods. The evaluations were conducted by highly trained personnel, provided with detailed procedures, in order to minimize the effects of human variability. These personnel performed the NDT on the test specimens without knowledge of the flaw locations and reported on the flaws detected. The performance of these tests was measured by comparing the flaws detected against the flaws present. The principal NDT methods utilized were radiographic, ultrasonic, penetrant, and eddy current. Holographic interferometry, acoustic emission monitoring, and replication methods were also applied on a reduced number of specimens. Generally, the best performance was shown by eddy current, ultrasonic, penetrant and holographic tests. Etching provided no measurable improvement, while proof loading improved flaw detectability. Data are shown that quantify the performances of the NDT methods applied.

Efficient computation of significance levels for multiple associations in large studies of correlated data, including genomewide association studies.

PubMed

Dudbridge, Frank; Koeleman, Bobby P C

2004-09-01

Large exploratory studies, including candidate-gene-association testing, genomewide linkage-disequilibrium scans, and array-expression experiments, are becoming increasingly common. A serious problem for such studies is that statistical power is compromised by the need to control the false-positive rate for a large family of tests. Because multiple true associations are anticipated, methods have been proposed that combine evidence from the most significant tests, as a more powerful alternative to individually adjusted tests. The practical application of these methods is currently limited by a reliance on permutation testing to account for the correlated nature of single-nucleotide polymorphism (SNP)-association data. On a genomewide scale, this is both very time-consuming and impractical for repeated explorations with standard marker panels. Here, we alleviate these problems by fitting analytic distributions to the empirical distribution of combined evidence. We fit extreme-value distributions for fixed lengths of combined evidence and a beta distribution for the most significant length. An initial phase of permutation sampling is required to fit these distributions, but it can be completed more quickly than a simple permutation test and need be done only once for each panel of tests, after which the fitted parameters give a reusable calibration of the panel. Our approach is also a more efficient alternative to a standard permutation test. We demonstrate the accuracy of our approach and compare its efficiency with that of permutation tests on genomewide SNP data released by the International HapMap Consortium. The estimation of analytic distributions for combined evidence will allow these powerful methods to be applied more widely in large exploratory studies.

A fast boosting-based screening method for large-scale association study in complex traits with genetic heterogeneity.

PubMed

Wang, Lu-Yong; Fasulo, D

2006-01-01

Genome-wide association study for complex diseases will generate massive amount of single nucleotide polymorphisms (SNPs) data. Univariate statistical test (i.e. Fisher exact test) was used to single out non-associated SNPs. However, the disease-susceptible SNPs may have little marginal effects in population and are unlikely to retain after the univariate tests. Also, model-based methods are impractical for large-scale dataset. Moreover, genetic heterogeneity makes the traditional methods harder to identify the genetic causes of diseases. A more recent random forest method provides a more robust method for screening the SNPs in thousands scale. However, for more large-scale data, i.e., Affymetrix Human Mapping 100K GeneChip data, a faster screening method is required to screening SNPs in whole-genome large scale association analysis with genetic heterogeneity. We propose a boosting-based method for rapid screening in large-scale analysis of complex traits in the presence of genetic heterogeneity. It provides a relatively fast and fairly good tool for screening and limiting the candidate SNPs for further more complex computational modeling task.

Multi-Reader ROC studies with Split-Plot Designs: A Comparison of Statistical Methods

PubMed Central

Obuchowski, Nancy A.; Gallas, Brandon D.; Hillis, Stephen L.

2012-01-01

Rationale and Objectives Multi-reader imaging trials often use a factorial design, where study patients undergo testing with all imaging modalities and readers interpret the results of all tests for all patients. A drawback of the design is the large number of interpretations required of each reader. Split-plot designs have been proposed as an alternative, in which one or a subset of readers interprets all images of a sample of patients, while other readers interpret the images of other samples of patients. In this paper we compare three methods of analysis for the split-plot design. Materials and Methods Three statistical methods are presented: Obuchowski-Rockette method modified for the split-plot design, a newly proposed marginal-mean ANOVA approach, and an extension of the three-sample U-statistic method. A simulation study using the Roe-Metz model was performed to compare the type I error rate, power and confidence interval coverage of the three test statistics. Results The type I error rates for all three methods are close to the nominal level but tend to be slightly conservative. The statistical power is nearly identical for the three methods. The coverage of 95% CIs fall close to the nominal coverage for small and large sample sizes. Conclusions The split-plot MRMC study design can be statistically efficient compared with the factorial design, reducing the number of interpretations required per reader. Three methods of analysis, shown to have nominal type I error rate, similar power, and nominal CI coverage, are available for this study design. PMID:23122570

The use and interpretation of in vitro data in regulatory toxicology: cosmetics, toiletries and household products.

PubMed

Indans, Ian

2002-02-28

There is currently a drive to eliminate animal testing for cosmetics, toiletries and household products; indeed, the European Union Cosmetics Directive aims to prohibit the use of experimental animals for the testing of finished cosmetic products after 2002. At present, national prohibitions are in place in the UK, Germany, Austria and the Netherlands, for the testing of finished cosmetic products and cosmetic ingredients. In the USA animal testing for certain types of finished products is mandatory. Against this background, the currently available regulatory in vitro tests comprise methods for eye irritation, skin corrosivity, genotoxicity, dermal penetration and photoirritation. The draft updates to the Organisation for Economic Co-operation and Development guidelines for eye and skin irritation advocate the use of in vitro or ex vivo methods prior to the commencement of animal studies. At present, testing for these endpoints cannot be completed in vitro, but potentially corrosive substances and products can be classified without the need for animal studies. Regulatory genotoxicity testing can be completed using only in vitro methods, provided that a clear negative outcome is obtained for each test. Data from dermal penetration studies may be used to refine risk assessments. Current developments in areas such as skin sensitisation and skin irritation promise that in the reasonably near future such information may be generated without the use of animals.

Evaluation of new aquatic toxicity test methods for oil dispersants

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

Pace, C.B.; Clark, J.R.; Bragin, G.E.

1994-12-31

Current aquatic toxicity test methods used for dispersant registration do not address real world exposure scenarios. Current test methods require 48 or 96 hour constant exposure conditions. In contrast, environmentally realistic exposures can be described as a pulse in which the initial concentration declines over time. Recent research using a specially designed testing apparatus (the California system) has demonstrated that exposure to Corexit 9527{reg_sign} under pulsed exposure conditions may be 3 to 22 times less toxic compared to continuous exposure scenarios. The objectives of this study were to compare results of toxicity tests using the California test system to resultsmore » from standardized tests, evaluate sensitivity of regional (Holmesimysis cast and Atherinops affinis) vs. standard test species (Mysidopsis bahia and Menidia beryllina) and determine if tests using the California test system and method are reproducible. All tests were conducted using Corexit 9527{reg_sign} as the test material. Standard toxicity tests conducted with M. bahia and H. cast resulted in LC50s similar to those from tests using the California apparatus. LC50s from tests conducted in the authors` laboratory with the California system and standard test species were within a factor of 2 to 6 of data previously reported for west coast species. Results of tests conducted with H. cast in the laboratory compared favorably to data reported by Singer et al. 1991.« less

The Effectiveness of the Component Impact Test Method for the Side Impact Injury Assessment of the Door Trim

NASA Astrophysics Data System (ADS)

Youn, Younghan; Koo, Jeong-Seo

The complete evaluation of the side vehicle structure and the occupant protection is only possible by means of the full scale side impact crash test. But, auto part manufacturers such as door trim makers can not conduct the test especially when the vehicle is under the developing process. The main objective of this study is to obtain the design guidelines by a simple component level impact test. The relationship between the target absorption energy and impactor speed were examined using the energy absorbed by the door trim. Since each different vehicle type required different energy levels on the door trim. A simple impact test method was developed to estimate abdominal injury by measuring reaction force of the impactor. The reaction force will be converted to a certain level of the energy by the proposed formula. The target of absorption energy for door trim only and the impact speed of simple impactor are derived theoretically based on the conservation of energy. With calculated speed of dummy and the effective mass of abdomen, the energy allocated in the abdomen area of door trim was calculated. The impactor speed can be calculated based on the equivalent energy of door trim absorbed during the full crash test. With the proposed design procedure for the door trim by a simple impact test method was demonstrated to evaluate the abdominal injury. This paper describes a study that was conducted to determine sensitivity of several design factors for reducing abdominal injury values using the matrix of orthogonal array method. In conclusion, with theoretical considerations and empirical test data, the main objective, standardization of door trim design using the simple impact test method was established.

Knowledge sharing to facilitate regulatory decision-making in regard to alternatives to animal testing: Report of an EPAA workshop.

PubMed

Ramirez, Tzutzuy; Beken, Sonja; Chlebus, Magda; Ellis, Graham; Griesinger, Claudius; De Jonghe, Sandra; Manou, Irene; Mehling, Annette; Reisinger, Kerstin; Rossi, Laura H; van Benthem, Jan; van der Laan, Jan Willem; Weissenhorn, Renate; Sauer, Ursula G

2015-10-01

The European Partnership for Alternative Approaches to Animal Testing (EPAA) convened a workshop Knowledge sharing to facilitate regulatory decision-making. Fifty invited participants from the European Commission, national and European agencies and bodies, different industry sectors (chemicals, cosmetics, fragrances, pharmaceuticals, vaccines), and animal protection organizations attended the workshop. Four case studies exemplarily revealed which procedures are in place to obtain regulatory acceptance of new test methods in different sectors. Breakout groups discussed the status quo identifying the following facilitators for regulatory acceptance of alternatives to animal testing: Networking and communication (including cross-sector collaboration, international cooperation and harmonization); involvement of regulatory agencies from the initial stages of test method development on; certainty on prerequisites for test method acceptance including the establishment of specific criteria for regulatory acceptance. Data sharing and intellectual property issues affect many aspects of test method development, validation and regulatory acceptance. In principle, all activities should address replacement, reduction and refinement methods (albeit animal testing is generally prohibited in the cosmetics sector). Provision of financial resources and education support all activities aiming at facilitating the acceptance and use of alternatives to animal testing. Overall, workshop participants recommended building confidence in new methodologies by applying and gaining experience with them. Copyright © 2015 Elsevier Inc. All rights reserved.

Trends in Mediation Analysis in Nursing Research: Improving Current Practice.

PubMed

Hertzog, Melody

2018-06-01

The purpose of this study was to describe common approaches used by nursing researchers to test mediation models and evaluate them within the context of current methodological advances. MEDLINE was used to locate studies testing a mediation model and published from 2004 to 2015 in nursing journals. Design (experimental/correlation, cross-sectional/longitudinal, model complexity) and analysis (method, inclusion of test of mediated effect, violations/discussion of assumptions, sample size/power) characteristics were coded for 456 studies. General trends were identified using descriptive statistics. Consistent with findings of reviews in other disciplines, evidence was found that nursing researchers may not be aware of the strong assumptions and serious limitations of their analyses. Suggestions for strengthening the rigor of such studies and an overview of current methods for testing more complex models, including longitudinal mediation processes, are presented.

Validation of catchment models for predicting land-use and climate change impacts. 1. Method

NASA Astrophysics Data System (ADS)

Ewen, J.; Parkin, G.

1996-02-01

Computer simulation models are increasingly being proposed as tools capable of giving water resource managers accurate predictions of the impact of changes in land-use and climate. Previous validation testing of catchment models is reviewed, and it is concluded that the methods used do not clearly test a model's fitness for such a purpose. A new generally applicable method is proposed. This involves the direct testing of fitness for purpose, uses established scientific techniques, and may be implemented within a quality assured programme of work. The new method is applied in Part 2 of this study (Parkin et al., J. Hydrol., 175:595-613, 1996).

Effect of Web Assisted Education Supported by Six Thinking Hats on Students' Academic Achievement in Science and Technology Classes

ERIC Educational Resources Information Center

Ercan, Orhan; Bilen, Kadir

2014-01-01

Advances in computer technologies and adoption of related methods and techniques in education have developed parallel to each other. This study focuses on the need to utilize more than one teaching method and technique in education rather than focusing on a single teaching method. By using the pre-test post-test and control group semi-experimental…

A Study Comparing the Pedagogical Effectiveness of Virtual Worlds and of Classical Methods

DTIC Science & Technology

2014-08-01

Approved for public release; distribution is unlimited. A Study Comparing the Pedagogical Effectiveness of Virtual Worlds and of Classical Methods...ABSTRACT A Study Comparing the Pedagogical Effectiveness of Virtual Worlds and of Classical Methods Report Title This experiment tests whether a virtual... PEDAGOGICAL EFFECTIVENESS OF VIRTUAL WORLDS AND OF TRADITIONAL TRAINING METHODS A Thesis by BENJAMIN PETERS

The admixture maximum likelihood test to test for association between rare variants and disease phenotypes.

PubMed

Tyrer, Jonathan P; Guo, Qi; Easton, Douglas F; Pharoah, Paul D P

2013-06-06

The development of genotyping arrays containing hundreds of thousands of rare variants across the genome and advances in high-throughput sequencing technologies have made feasible empirical genetic association studies to search for rare disease susceptibility alleles. As single variant testing is underpowered to detect associations, the development of statistical methods to combine analysis across variants - so-called "burden tests" - is an area of active research interest. We previously developed a method, the admixture maximum likelihood test, to test multiple, common variants for association with a trait of interest. We have extended this method, called the rare admixture maximum likelihood test (RAML), for the analysis of rare variants. In this paper we compare the performance of RAML with six other burden tests designed to test for association of rare variants. We used simulation testing over a range of scenarios to test the power of RAML compared to the other rare variant association testing methods. These scenarios modelled differences in effect variability, the average direction of effect and the proportion of associated variants. We evaluated the power for all the different scenarios. RAML tended to have the greatest power for most scenarios where the proportion of associated variants was small, whereas SKAT-O performed a little better for the scenarios with a higher proportion of associated variants. The RAML method makes no assumptions about the proportion of variants that are associated with the phenotype of interest or the magnitude and direction of their effect. The method is flexible and can be applied to both dichotomous and quantitative traits and allows for the inclusion of covariates in the underlying regression model. The RAML method performed well compared to the other methods over a wide range of scenarios. Generally power was moderate in most of the scenarios, underlying the need for large sample sizes in any form of association testing.

Bio-Contamination Control for Spacesuit Garments - A Preliminary Study

NASA Technical Reports Server (NTRS)

Rhodes, Richard; Korona, Adam; Orndoff, Evelyn; Ott, Mark; Poritz, Darwin

2010-01-01

This paper outlines a preliminary study to review, test, and improve upon the current state of spacesuit bio-contamination control. The study includes an evaluation of current and advanced suit materials, ground and on-orbit cleaning methods, and microbial test and analysis methods. The first aspect of this study was to identify potential anti-microbial textiles and cleaning agents, and to review current microbial test methods. The anti-microbial cleaning agent and textile market survey included a review of current commercial-off-the-shelf (COTS) products that could potentially be used as future space flight hardware. This review included replacements for any of the softgood layers that may become contaminated during an extravehicular activity (EVA), including the pressure bladder, liquid cooling garment, and ancillary comfort undergarment. After a series of COTS anti-microbial textiles and clean ing agents were identified, a series of four tests were conducted: (1) a stacked configuration test that was conducted in order to review how bio-contamination would propagate through the various suit layers, (2) a individual materials test that evaluated how well each softgood layer either promoted or repressed growth, (3) a cleaning agent test that evaluated the efficacy on each of the baseline bladders, and (4) an evaluation of various COTS anti-microbial textiles. All antimicrobial COTS materials tested appeared to control bacteria colony forming unit (CFU) growth better than the Thermal Comfort Undergarment (TCU) and ACES Liquid Cooling Garment (LCG)/EMU Liquid Cooling Ventilation Garment (LCVG) materials currently in use. However, a comparison of fungi CFU growth in COTS to current suit materials appeared to vary per material. All cleaning agents tested in this study appeared to inhibit the level of bacteria and fungi growth to acceptable levels for short duration tests. While several trends can be obtained from the current analysis, a series of test improvements are described for future microbial testing.

Quantitative methods used in Australian health promotion research: a review of publications from 1992-2002.

PubMed

Smith, Ben J; Zehle, Katharina; Bauman, Adrian E; Chau, Josephine; Hawkshaw, Barbara; Frost, Steven; Thomas, Margaret

2006-04-01

This study examined the use of quantitative methods in Australian health promotion research in order to identify methodological trends and priorities for strengthening the evidence base for health promotion. Australian health promotion articles were identified by hand searching publications from 1992-2002 in six journals: Health Promotion Journal of Australia, Australian and New Zealand journal of Public Health, Health Promotion International, Health Education Research, Health Education and Behavior and the American Journal of Health Promotion. The study designs and statistical methods used in articles presenting quantitative research were recorded. 591 (57.7%) of the 1,025 articles used quantitative methods. Cross-sectional designs were used in the majority (54.3%) of studies with pre- and post-test (14.6%) and post-test only (9.5%) the next most common designs. Bivariate statistical methods were used in 45.9% of papers, multivariate methods in 27.1% and simple numbers and proportions in 25.4%. Few studies used higher-level statistical techniques. While most studies used quantitative methods, the majority were descriptive in nature. The study designs and statistical methods used provided limited scope for demonstrating intervention effects or understanding the determinants of change.

Accelerated radiation damage testing of x-ray mask membrane materials

NASA Astrophysics Data System (ADS)

Seese, Philip A.; Cummings, Kevin D.; Resnick, Douglas J.; Yanof, Arnold W.; Johnson, William A.; Wells, Gregory M.; Wallace, John P.

1993-06-01

An accelerated test method and resulting metrology data are presented to show the effects of x- ray radiation on various x-ray mask membrane materials. A focused x-ray beam effectively reduces the radiation time to 1/5 of that required by normal exposure beam flux. Absolute image displacement results determined by this method indicate imperceptible movement for boron-doped silicon and silicon carbide membranes at a total incident dose of 500 KJ/cm2, while image displacement for diamond is 50 nm at 150 KJ/cm2 and silicon nitride is 70 nm at 36 KJ/cm2. Studies of temperature rise during the radiation test and effects of the high flux radiation, i.e., reciprocity tests, demonstrate the validity of this test method.

Evaluation of Pyrrolidonyl Arylamidase Activity in Staphylococcus delphini.

PubMed

Compton, Samantha T; Kania, Stephen A; Robertson, Amy E; Lawhon, Sara D; Jenkins, Stephen G; Westblade, Lars F; Bemis, David A

2017-03-01

Clinical reference textbooks lack data for pyrrolidonyl arylamidase (PYR) activity in Staphylococcus delphini This study evaluated PYR activities of 21 S. delphini strains by reference broth, rapid disc, and rapid slide methods. Species and subgroup identifications were confirmed by nucleic acid-based methods and included nine group A and 12 group B strains. Testing by rapid PYR methods with products from four manufacturers was performed at two testing locations, and, with the exception of one strain tested at one location using reagents from one manufacturer, each S. delphini strain tested positive for PYR activity. Therefore, PYR may be a useful single-test adjunct for distinguishing Staphylococcus aureus from S. delphini and other members of the Staphylococcus intermedius group. Copyright © 2017 American Society for Microbiology.

Quantifying Acoustic Impacts on Marine Mammals and Sea Turtles: Methods and Analytical Approach for Phase III Training and Testing

DTIC Science & Technology

2017-06-16

Acoustic Impacts on Marine Mammals and Sea Turtles: Methods and Analytical Approach for Phase III Training and Testing Sarah A. Blackstock Joseph O...December 2017 4. TITLE AND SUBTITLE Quantifying Acoustic Impacts on Marine Mammals and Sea Turtles: Methods and Analytical Approach for Phase III...Navy’s Phase III Study Areas as described in each Environmental Impact Statement/ Overseas Environmental Impact Statement and describes the methods

Testing Methods for Challenging the National Wetland Plant List: Using Tsuga canadensis (L.) Carr. (Eastern Hemlock) as a Case Study

DTIC Science & Technology

2017-07-01

ESRI (Nature Conservancy and Environmental Systems Research Institute). 1994. Field Methods . In Field Methods for Vegetation Mapping: United States...ER D C/ CR RE L TR -1 7- 9 Wetlands Regulatory Assistance Program (WRAP) Testing Methods for Challenging the National Wetland Plant List...Robert W. Lichvar and Jennifer J. Goulet July 2017 Approved for public release; distribution is unlimited. The U.S. Army Engineer Research

The transmission/disequilibrium test and parental-genotype reconstruction: the reconstruction-combined transmission/ disequilibrium test.

PubMed Central

Knapp, M

1999-01-01

Spielman and Ewens recently proposed a method for testing a marker for linkage with a disease, which combines data from families with and without information on parental genotypes. For some families without parental-genotype information, it may be possible to reconstruct missing parental genotypes from the genotypes of their offspring. The treatment of such a reconstructed family as if parental genotypes have been typed, however, can introduce bias. In the present study, a new method is presented that employs parental-genotype reconstruction and corrects for the biases resulting from reconstruction. The results of an application of this method to a real data set and of a simulation study suggest that this approach may increase the power to detect linkage. PMID:10053021

A method of determining bending properties of poultry long bones using beam analysis and micro-CT data.

PubMed

Vaughan, Patrick E; Orth, Michael W; Haut, Roger C; Karcher, Darrin M

2016-01-01

While conventional mechanical testing has been regarded as a gold standard for the evaluation of bone heath in numerous studies, with recent advances in medical imaging, virtual methods of biomechanics are rapidly evolving in the human literature. The objective of the current study was to evaluate the feasibility of determining the elastic and failure properties of poultry long bones using established methods of analysis from the human literature. In order to incorporate a large range of bone sizes and densities, a small number of specimens were utilized from an ongoing study of Regmi et al. (2016) that involved humeri and tibiae from 3 groups of animals (10 from each) including aviary, enriched, and conventional housing systems. Half the animals from each group were used for 'training' that involved the development of a regression equation relating bone density and geometry to bending properties from conventional mechanical tests. The remaining specimens from each group were used for 'testing' in which the mechanical properties from conventional tests were compared to those predicted by the regression equations. Based on the regression equations, the coefficients of determination for the 'test' set of data were 0.798 for bending bone stiffness and 0.901 for the yield (or failure) moment of the bones. All regression slopes and intercepts values for the tests versus predicted plots were not significantly different from 1 and 0, respectively. The study showed the feasibility of developing future methods of virtual biomechanics for the evaluation of poultry long bones. With further development, virtual biomechanics may have utility in future in vivo studies to assess laying hen bone health over time without the need to sacrifice large groups of animals at each time point. © 2016 Poultry Science Association Inc.

Role of the Direct Teaching Method in the Academic Achievement of Students in English at the Secondary Level

ERIC Educational Resources Information Center

Hussain, Ishtiaq; Inamullah, Hafiz; Naseer-Ud-Din, Muhammad; Hafizatullah, Hafiz

2009-01-01

The major objective of this study was to determine the role of the direct teaching method in the academic achievement of students in English at the secondary level. To achieve the said objective, the "Solomon Four-Design pre-test/post-test equivalent group design" was considered to be the most useful design for this study. The pre-test…

Methodical Challenges Concerning the Draw-A-Scientist Test: A Critical View about the Assessment and Evaluation of Learners' Conceptions of Scientists

ERIC Educational Resources Information Center

Reinisch, Bianca; Krell, Moritz; Hergert, Susann; Gogolin, Sarah; Krüger, Dirk

2017-01-01

Students' and pre-service teachers' conceptions of scientists have been assessed in a variety of studies. One of the most commonly used instruments is the Draw-A-Scientist Test (DAST) which offers the advantage that no verbal skills are needed by the participants. In some studies, methodical challenges related to the DAST have been discussed; for…

The estimation of 3D SAR distributions in the human head from mobile phone compliance testing data for epidemiological studies

NASA Astrophysics Data System (ADS)

Wake, Kanako; Varsier, Nadège; Watanabe, Soichi; Taki, Masao; Wiart, Joe; Mann, Simon; Deltour, Isabelle; Cardis, Elisabeth

2009-10-01

A worldwide epidemiological study called 'INTERPHONE' has been conducted to estimate the hypothetical relationship between brain tumors and mobile phone use. In this study, we proposed a method to estimate 3D distribution of the specific absorption rate (SAR) in the human head due to mobile phone use to provide the exposure gradient for epidemiological studies. 3D SAR distributions due to exposure to an electromagnetic field from mobile phones are estimated from mobile phone compliance testing data for actual devices. The data for compliance testing are measured only on the surface in the region near the device and in a small 3D region around the maximum on the surface in a homogeneous phantom with a specific shape. The method includes an interpolation/extrapolation and a head shape conversion. With the interpolation/extrapolation, SAR distributions in the whole head are estimated from the limited measured data. 3D SAR distributions in the numerical head models, where the tumor location is identified in the epidemiological studies, are obtained from measured SAR data with the head shape conversion by projection. Validation of the proposed method was performed experimentally and numerically. It was confirmed that the proposed method provided good estimation of 3D SAR distribution in the head, especially in the brain, which is the tissue of major interest in epidemiological studies. We conclude that it is possible to estimate 3D SAR distributions in a realistic head model from the data obtained by compliance testing measurements to provide a measure for the exposure gradient in specific locations of the brain for the purpose of exposure assessment in epidemiological studies. The proposed method has been used in several studies in the INTERPHONE.

The estimation of 3D SAR distributions in the human head from mobile phone compliance testing data for epidemiological studies.

PubMed

Wake, Kanako; Varsier, Nadège; Watanabe, Soichi; Taki, Masao; Wiart, Joe; Mann, Simon; Deltour, Isabelle; Cardis, Elisabeth

2009-10-07

A worldwide epidemiological study called 'INTERPHONE' has been conducted to estimate the hypothetical relationship between brain tumors and mobile phone use. In this study, we proposed a method to estimate 3D distribution of the specific absorption rate (SAR) in the human head due to mobile phone use to provide the exposure gradient for epidemiological studies. 3D SAR distributions due to exposure to an electromagnetic field from mobile phones are estimated from mobile phone compliance testing data for actual devices. The data for compliance testing are measured only on the surface in the region near the device and in a small 3D region around the maximum on the surface in a homogeneous phantom with a specific shape. The method includes an interpolation/extrapolation and a head shape conversion. With the interpolation/extrapolation, SAR distributions in the whole head are estimated from the limited measured data. 3D SAR distributions in the numerical head models, where the tumor location is identified in the epidemiological studies, are obtained from measured SAR data with the head shape conversion by projection. Validation of the proposed method was performed experimentally and numerically. It was confirmed that the proposed method provided good estimation of 3D SAR distribution in the head, especially in the brain, which is the tissue of major interest in epidemiological studies. We conclude that it is possible to estimate 3D SAR distributions in a realistic head model from the data obtained by compliance testing measurements to provide a measure for the exposure gradient in specific locations of the brain for the purpose of exposure assessment in epidemiological studies. The proposed method has been used in several studies in the INTERPHONE.

Selection and Reporting of Statistical Methods to Assess Reliability of a Diagnostic Test: Conformity to Recommended Methods in a Peer-Reviewed Journal

PubMed Central

Park, Ji Eun; Han, Kyunghwa; Sung, Yu Sub; Chung, Mi Sun; Koo, Hyun Jung; Yoon, Hee Mang; Choi, Young Jun; Lee, Seung Soo; Kim, Kyung Won; Shin, Youngbin; An, Suah; Cho, Hyo-Min

2017-01-01

Objective To evaluate the frequency and adequacy of statistical analyses in a general radiology journal when reporting a reliability analysis for a diagnostic test. Materials and Methods Sixty-three studies of diagnostic test accuracy (DTA) and 36 studies reporting reliability analyses published in the Korean Journal of Radiology between 2012 and 2016 were analyzed. Studies were judged using the methodological guidelines of the Radiological Society of North America-Quantitative Imaging Biomarkers Alliance (RSNA-QIBA), and COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) initiative. DTA studies were evaluated by nine editorial board members of the journal. Reliability studies were evaluated by study reviewers experienced with reliability analysis. Results Thirty-one (49.2%) of the 63 DTA studies did not include a reliability analysis when deemed necessary. Among the 36 reliability studies, proper statistical methods were used in all (5/5) studies dealing with dichotomous/nominal data, 46.7% (7/15) of studies dealing with ordinal data, and 95.2% (20/21) of studies dealing with continuous data. Statistical methods were described in sufficient detail regarding weighted kappa in 28.6% (2/7) of studies and regarding the model and assumptions of intraclass correlation coefficient in 35.3% (6/17) and 29.4% (5/17) of studies, respectively. Reliability parameters were used as if they were agreement parameters in 23.1% (3/13) of studies. Reproducibility and repeatability were used incorrectly in 20% (3/15) of studies. Conclusion Greater attention to the importance of reporting reliability, thorough description of the related statistical methods, efforts not to neglect agreement parameters, and better use of relevant terminology is necessary. PMID:29089821

A Comparison of Didactic and Inquiry Teaching Methods in a Rural Community College Earth Science Course

NASA Astrophysics Data System (ADS)

Beam, Margery Elizabeth

The combination of increasing enrollment and the importance of providing transfer students a solid foundation in science calls for science faculty to evaluate teaching methods in rural community colleges. The purpose of this study was to examine and compare the effectiveness of two teaching methods, inquiry teaching methods and didactic teaching methods, applied in a rural community college earth science course. Two groups of students were taught the same content via inquiry and didactic teaching methods. Analysis of quantitative data included a non-parametric ranking statistical testing method in which the difference between the rankings and the median of the post-test scores was analyzed for significance. Results indicated there was not a significant statistical difference between the teaching methods for the group of students participating in the research. The practical and educational significance of this study provides valuable perspectives on teaching methods and student learning styles in rural community colleges.

A Comparative Study of Online Item Calibration Methods in Multidimensional Computerized Adaptive Testing

ERIC Educational Resources Information Center

Chen, Ping

2017-01-01

Calibration of new items online has been an important topic in item replenishment for multidimensional computerized adaptive testing (MCAT). Several online calibration methods have been proposed for MCAT, such as multidimensional "one expectation-maximization (EM) cycle" (M-OEM) and multidimensional "multiple EM cycles"…

Using the Climbing Drum Peel (CDP) Test to Obtain a G(sub IC) value for Core/Facesheet Bonds

NASA Technical Reports Server (NTRS)

Nettles, A. T.; Gregory, Elizabeth D.; Jackson, Justin R.

2006-01-01

A method of measuring the Mode I fracture toughness of core/facesheet bonds in sandwich Structures is desired, particularly with the widespread use of models that need this data as input. This study examined if a critical strain energy release rate, G(sub IC), can be obtained from the climbing drum peel (CDP) test. The CDP test is relatively simple to perform and does not rely on measuring small crack lengths such as required by the double cantilever beam (DCB) test. Simple energy methods were used to calculate G(sub IC) from CDP test data on composite facesheets bonded to a honeycomb core. Facesheet thicknesses from 2 to 5 plies were tested to examine the upper and lower bounds on facesheet thickness requirements. Results from the study suggest that the CDP test, with certain provisions, can be used to find the GIG value of a core/facesheet bond.

Experimental Design for a Sponge-Wipe Study to Relate the Recovery Efficiency and False Negative Rate to the Concentration of a Bacillus anthracis Surrogate for Six Surface Materials

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

Piepel, Gregory F.; Amidan, Brett G.; Krauter, Paula

2011-05-01

Two concerns were raised by the Government Accountability Office following the 2001 building contaminations via letters containing Bacillus anthracis (BA). These included the: 1) lack of validated sampling methods, and 2) need to use statistical sampling to quantify the confidence of no contamination when all samples have negative results. Critical to addressing these concerns is quantifying the false negative rate (FNR). The FNR may depend on the 1) method of contaminant deposition, 2) surface concentration of the contaminant, 3) surface material being sampled, 4) sample collection method, 5) sample storage/transportation conditions, 6) sample processing method, and 7) sample analytical method.more » A review of the literature found 17 laboratory studies that focused on swab, wipe, or vacuum samples collected from a variety of surface materials contaminated by BA or a surrogate, and used culture methods to determine the surface contaminant concentration. These studies quantified performance of the sampling and analysis methods in terms of recovery efficiency (RE) and not FNR (which left a major gap in available information). Quantifying the FNR under a variety of conditions is a key aspect of validating sample and analysis methods, and also for calculating the confidence in characterization or clearance decisions based on a statistical sampling plan. A laboratory study was planned to partially fill the gap in FNR results. This report documents the experimental design developed by Pacific Northwest National Laboratory and Sandia National Laboratories (SNL) for a sponge-wipe method. The testing was performed by SNL and is now completed. The study investigated the effects on key response variables from six surface materials contaminated with eight surface concentrations of a BA surrogate (Bacillus atrophaeus). The key response variables include measures of the contamination on test coupons of surface materials tested, contamination recovered from coupons by sponge-wipe samples, RE, and FNR. The experimental design involves 16 test runs, performed in two blocks of eight runs. Three surface materials (stainless steel, vinyl tile, and ceramic tile) were tested in the first block, while three other surface materials (plastic, painted wood paneling, and faux leather) were tested in the second block. The eight surface concentrations of the surrogate were randomly assigned to test runs within each block. Some of the concentrations were very low and presented challenges for deposition, sampling, and analysis. However, such tests are needed to investigate RE and FNR over the full range of concentrations of interest. In each run, there were 10 test coupons of each of the three surface materials. A positive control sample was generated at the same time as each test sample. The positive control results will be used to 1) calculate RE values for the wipe sampling and analysis method, and 2) fit RE- and FNR-concentration equations, for each of the six surface materials. Data analyses will support 1) estimating the FNR for each combination of contaminant concentration and surface material, 2) estimating the surface concentrations and their uncertainties of the contaminant for each combination of concentration and surface material, 3) estimating RE (%) and their uncertainties for each combination of contaminant concentration and surface material, 4) fitting FNR-concentration and RE-concentration equations for each of the six surface materials, 5) assessing goodness-of-fit of the equations, and 6) quantifying the uncertainty in FNR and RE predictions made with the fitted equations.« less

Reveal Salmonella 2.0 test for detection of Salmonella spp. in foods and environmental samples. Performance Tested Method 960801.

PubMed

Hoerner, Rebecca; Feldpausch, Jill; Gray, R Lucas; Curry, Stephanie; Islam, Zahidul; Goldy, Tim; Klein, Frank; Tadese, Theodros; Rice, Jennifer; Mozola, Mark

2011-01-01

Reveal Salmonella 2.0 is an improved version of the original Reveal Salmonella lateral flow immunoassay and is applicable to the detection of Salmonella enterica serogroups A-E in a variety of food and environmental samples. A Performance Tested Method validation study was conducted to compare performance of the Reveal 2.0 method with that of the U.S. Department of Agriculture-Food Safety and Inspection Service or U.S. Food and Drug Administration/Bacteriological Analytical Manual reference culture methods for detection of Salmonella spp. in chicken carcass rinse, raw ground turkey, raw ground beef, hot dogs, raw shrimp, a ready-to-eat meal product, dry pet food, ice cream, spinach, cantaloupe, peanut butter, stainless steel surface, and sprout irrigation water. In a total of 17 trials performed internally and four trials performed in an independent laboratory, there were no statistically significant differences in performance of the Reveal 2.0 and reference culture procedures as determined by Chi-square analysis, with the exception of one trial with stainless steel surface and one trial with sprout irrigation water where there were significantly more positive results by the Reveal 2.0 method. Considering all data generated in testing food samples using enrichment procedures specifically designed for the Reveal method, overall sensitivity of the Reveal method relative to the reference culture methods was 99%. In testing environmental samples, sensitivity of the Reveal method relative to the reference culture method was 164%. For select foods, use of the Reveal test in conjunction with reference method enrichment resulted in overall sensitivity of 92%. There were no unconfirmed positive results on uninoculated control samples in any trials for specificity of 100%. In inclusivity testing, 102 different Salmonella serovars belonging to serogroups A-E were tested and 99 were consistently positive in the Reveal test. In exclusivity testing of 33 strains of non-salmonellae representing 14 genera, 32 were negative when tested with Reveal following nonselective enrichment, and the remaining strain was found to be substantially inhibited by the enrichment media used with the Reveal method. Results of ruggedness testing showed that the Reveal test produces accurate results even with substantial deviation in sample volume or device development time.

Testing the efficiency of rover science protocols for robotic sample selection: A GeoHeuristic Operational Strategies Test

NASA Astrophysics Data System (ADS)

Yingst, R. A.; Bartley, J. K.; Chidsey, T. C.; Cohen, B. A.; Gilleaudeau, G. J.; Hynek, B. M.; Kah, L. C.; Minitti, M. E.; Williams, R. M. E.; Black, S.; Gemperline, J.; Schaufler, R.; Thomas, R. J.

2018-05-01

The GHOST field tests are designed to isolate and test science-driven rover operations protocols, to determine best practices. During a recent field test at a potential Mars 2020 landing site analog, we tested two Mars Science Laboratory data-acquisition and decision-making methods to assess resulting science return and sample quality: a linear method, where sites of interest are studied in the order encountered, and a "walkabout-first" method, where sites of interest are examined remotely before down-selecting to a subset of sites that are interrogated with more resource-intensive instruments. The walkabout method cost less time and fewer resources, while increasing confidence in interpretations. Contextual data critical to evaluating site geology was acquired earlier than for the linear method, and given a higher priority, which resulted in development of more mature hypotheses earlier in the analysis process. Combined, this saved time and energy in the collection of data with more limited spatial coverage. Based on these results, we suggest that the walkabout method be used where doing so would provide early context and time for the science team to develop hypotheses-critical tests; and that in gathering context, coverage may be more important than higher resolution.

Assessment of learning, memory, and attention in developmental neurotoxicity regulatory studies: synthesis, commentary, and recommendations.

PubMed

Vorhees, Charles V; Makris, Susan L

2015-01-01

Cognitive tests of learning and memory (L&M) have been required by U.S. Environmental Protection Agency (EPA) developmental neurotoxicity test (DNT) guidelines for more than two decades. To evaluate the utility of these guidelines, the EPA reviewed 69 pesticide DNT studies. This review found that the DNT provided or could provide the point-of-departure for risk assessment by showing the Lowest Observable Adverse Effect Level (LOAEL) in 28 of these studies in relation to other reported end points. Among the behavioral tests, locomotor activity and auditory/acoustic startle provided the most LOAELs, and tests of cognitive function and the Functional Observational Battery (FOB) the fewest. Two issues arose from the review: (1) what is the relative utility of cognitive tests versus tests of unconditioned behavior, and (2) how might cognitive tests be improved? The EPA sponsored a symposium to address this. Bushnell reviewed studies in which both screening (locomotor activity, FOB, reflex ontogeny, etc.) and complex tests (those requiring training) were used within the same study; he found relatively little evidence that complex tests provided a LOAEL lower than screening tests (with exceptions). Levin reviewed reasons for including cognitive tests in regulatory studies and methods and evidence for the radial arm maze and its place in developmental neurotoxicity assessments. Driscoll and Strupp reviewed the value of serial reaction time operant methods for assessing executive function in developmental neurotoxicity studies. Vorhees and Williams reviewed the value of allocentric (spatial) and egocentric cognitive tests and presented methods for using the Morris water maze for spatial and the Cincinnati water maze for egocentric cognitive assessment. They also reviewed the possible use of water radial mazes. The relatively lower impact of cognitive tests in previous DNT studies in the face of the frequency of human complaints of chemical-induced cognitive dysfunction indicates that animal cognitive tests need improvement. The contributors to this symposium suggest that if the guidelines are updated, they be made more specific by recommending preferred tests and providing greater detail on key characteristics of such tests. Additionally, it is recommended that guidance be developed to address important issues with cognitive tests and to provide the information needed to improve the design, conduct, and interpretation of tests of higher function within a regulatory context. These steps will maximize the value of cognitive tests for use in hazard evaluation and risk assessment. Copyright © 2015 Elsevier Inc. All rights reserved.

Study Of Nondestructive Techniques For Testing Composites

NASA Technical Reports Server (NTRS)

Roth, D.; Kautz, H.; Draper, S.; Bansal, N.; Bowles, K.; Bashyam, M.; Bishop, C.

1995-01-01

Study evaluates some nondestructive methods for characterizing ceramic-, metal-, and polymer-matrix composite materials. Results demonstrated utility of two ultrasonic methods for obtaining quantitative data on microstructural anomalies in composite materials.

Hypothesis testing on the fractal structure of behavioral sequences: the Bayesian assessment of scaling methodology.

PubMed

Moscoso del Prado Martín, Fermín

2013-12-01

I introduce the Bayesian assessment of scaling (BAS), a simple but powerful Bayesian hypothesis contrast methodology that can be used to test hypotheses on the scaling regime exhibited by a sequence of behavioral data. Rather than comparing parametric models, as typically done in previous approaches, the BAS offers a direct, nonparametric way to test whether a time series exhibits fractal scaling. The BAS provides a simpler and faster test than do previous methods, and the code for making the required computations is provided. The method also enables testing of finely specified hypotheses on the scaling indices, something that was not possible with the previously available methods. I then present 4 simulation studies showing that the BAS methodology outperforms the other methods used in the psychological literature. I conclude with a discussion of methodological issues on fractal analyses in experimental psychology. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Recent advances in testing of microsphere drug delivery systems.

PubMed

Andhariya, Janki V; Burgess, Diane J

2016-01-01

This review discusses advances in the field of microsphere testing. In vitro release-testing methods such as sample and separate, dialysis membrane sacs and USP apparatus IV have been used for microspheres. Based on comparisons of these methods, USP apparatus IV is currently the method of choice. Accelerated in vitro release tests have been developed to shorten the testing time for quality control purposes. In vitro-in vivo correlations using real-time and accelerated release data have been developed, to minimize the need to conduct in vivo performance evaluation. Storage stability studies have been conducted to investigate the influence of various environmental factors on microsphere quality throughout the product shelf life. New tests such as the floating test and the in vitro wash-off test have been developed along with advancement in characterization techniques for other physico-chemical parameters such as particle size, drug content, and thermal properties. Although significant developments have been made in microsphere release testing, there is still a lack of guidance in this area. Microsphere storage stability studies should be extended to include microspheres containing large molecules. An agreement needs to be reached on the use of particle sizing techniques to avoid inconsistent data. An approach needs to be developed to determine total moisture content of microspheres.

VIDAS Listeria species Xpress (LSX).

PubMed

Johnson, Ronald; Mills, John

2013-01-01

The AOAC GovVal study compared the VIDAS Listeria species Xpress (LSX) to the Health Products and Food Branch MFHPB-30 reference method for detection of Listeria on stainless steel. The LSX method utilizes a novel and proprietary enrichment media, Listeria Xpress broth, enabling detection of Listeria species in environmental samples with the automated VIDAS in a minimum of 26 h. The LSX method also includes the use of the chromogenic media, chromID Ottaviani Agosti Agar (OAA) and chromID Lmono for confirmation of LSX presumptive results. In previous AOAC validation studies comparing VIDAS LSX to the U.S. Food and Drug Administration's Bacteriological Analytical Manual (FDA-BAM) and the U.S. Department of Agriculture-Food Safety and Inspection Service (USDA-FSIS) reference methods, the LSX method was approved as AOAC Official Method 2010.02 for the detection of Listeria species in dairy products, vegetables, seafood, raw meats and poultry, and processed meats and poultry, and as AOAC Performance Tested Method 100501 in a variety of foods and on environmental surfaces. The GovVal comparative study included 20 replicate test portions each at two contamination levels for stainless steel where fractionally positive results (5-15 positive results/20 replicate portions tested) were obtained by at least one method at one level. Five uncontaminated controls were included. In the stainless steel artificially contaminated surface study, there were 25 confirmed positives by the VIDAS LSX assay and 22 confirmed positives by the standard culture methods. Chi-square analysis indicated no statistical differences between the VIDAS LSX method and the MFHPB-30 standard methods at the 5% level of significance. Confirmation of presumptive LSX results with the chromogenic OAA and Lmono media was shown to be equivalent to the appropriate reference method agars. The data in this study demonstrate that the VIDAS LSX method is an acceptable alternative method to the MFHPB-30 standard culture method for the detection of Listeria species on stainless steel.

Reevaluation of confirmatory tests for human T-cell leukemia virus Type 1 using a luciferase immunoprecipitation system in blood donors.

PubMed

Furuta, Rika A; Ma, Guangyong; Matsuoka, Masao; Otani, Satoshi; Matsukura, Harumichi; Hirayama, Fumiya

2015-04-01

Recently, Japanese Red Cross blood centers have changed the confirmatory test method from an indirect immunofluorescence (IF) technique to Western blotting (WB) for antibodies against human T-cell leukemia virus Type 1 (HTLV-1). In this study, these HTLV-1 tests were assessed using another sensitive method, that is, a luciferase immunoprecipitation system (LIPS), to identify a better confirmatory test for HTLV-1 infection. Plasma samples from 54 qualified donors and 114 HTLV-1 screening-positive donors were tested by LIPS for antibodies against HTLV-1 Gag, Tax, Env, and HBZ recombinant proteins. The donors were categorized into six groups, namely, (Group I) qualified donors, screening positive; (Group II) IF positive; (Group III) IF negative; (Group IV) WB positive; (Group V) WB negative; and (Group VI) screening positive in the previous blood donation, but WB-indeterminate during this study period. In Groups II and IV, all plasma samples tested positive by LIPS for antibodies against Gag and Env proteins. In Group V, all samples tested negative by LIPS, whereas some Group III samples reacted with single or double antigens in LIPS. In Group VI, the LIPS test identified a donor with suspected HTLV-1 infection. The first case of a blood donor with plasma that reacted with HBZ was identified by LIPS. Reevaluation of the current HTLV-1 screening method using the LIPS test showed that both confirmatory tests had similar sensitivity and specificity only when WB indeterminate results were eliminated. LIPS is a promising method for detecting and characterizing HTLV-1 antibodies. © 2014 AABB.

In vitro eye corrosion study of agrochemicals on isolated chicken eye.

PubMed

Buda, I; Budai, P; Szabó, R; Lehel, J

2013-01-01

Agrochemicals must undergo numberless toxicological tests before marketing. The eye irritation test is part of this test packet. Nowadays, OECD 405 can be used to classify the irritation potential of substances, the base of the OECD 405 guideline is the Draize test, which is one of the most criticized in vivo methods because of the injuries of the test animals and subjective nature of the test in recording the results. Therefore, several in vitro tests have been developed to replace totally or partly the in vivo eye irritation testing. The isolated chicken eye test method (OECD 438), which was used, is one of these alternative methods. Five different agrochemicals were examined in the following way: All test compounds were applied in a single dose onto the cornea of isolated chicken eyes in order to potentially classify the test compounds as ocular corrosive and/or severe irritant. The damages caused by the test substances were assessed by the determination of corneal swelling, opacity, fluorescein retention and morphological effects. These parameters were evaluated pre-treatment and starting at approximately 30, 75, 120, 180, and 240 minutes after the post-treatment rinse. The endpoints evaluated were corneal opacity, swelling, fluorescein retention and morphological effects. All of the endpoints, with the exception of fluorescein retention (which was determined only at pre-treatment and 30 minutes after test substance exposure) were determined at each of the above time points. Positive and negative controls were used and they showed the expected results in each study. In these in vitro eye corrosives and severe irritants studies, using the Isolated Chicken Eye model with five different products, no ocular corrosion or severe irritation potential were observed. These results correspond to the available information about the tested agrochemicals, so these studies with isolated chicken eye are considered to be successful.

Multiple Phenotype Association Tests Using Summary Statistics in Genome-Wide Association Studies

PubMed Central

Liu, Zhonghua; Lin, Xihong

2017-01-01

Summary We study in this paper jointly testing the associations of a genetic variant with correlated multiple phenotypes using the summary statistics of individual phenotype analysis from Genome-Wide Association Studies (GWASs). We estimated the between-phenotype correlation matrix using the summary statistics of individual phenotype GWAS analyses, and developed genetic association tests for multiple phenotypes by accounting for between-phenotype correlation without the need to access individual-level data. Since genetic variants often affect multiple phenotypes differently across the genome and the between-phenotype correlation can be arbitrary, we proposed robust and powerful multiple phenotype testing procedures by jointly testing a common mean and a variance component in linear mixed models for summary statistics. We computed the p-values of the proposed tests analytically. This computational advantage makes our methods practically appealing in large-scale GWASs. We performed simulation studies to show that the proposed tests maintained correct type I error rates, and to compare their powers in various settings with the existing methods. We applied the proposed tests to a GWAS Global Lipids Genetics Consortium summary statistics data set and identified additional genetic variants that were missed by the original single-trait analysis. PMID:28653391

Multiple phenotype association tests using summary statistics in genome-wide association studies.

PubMed

Liu, Zhonghua; Lin, Xihong

2018-03-01

We study in this article jointly testing the associations of a genetic variant with correlated multiple phenotypes using the summary statistics of individual phenotype analysis from Genome-Wide Association Studies (GWASs). We estimated the between-phenotype correlation matrix using the summary statistics of individual phenotype GWAS analyses, and developed genetic association tests for multiple phenotypes by accounting for between-phenotype correlation without the need to access individual-level data. Since genetic variants often affect multiple phenotypes differently across the genome and the between-phenotype correlation can be arbitrary, we proposed robust and powerful multiple phenotype testing procedures by jointly testing a common mean and a variance component in linear mixed models for summary statistics. We computed the p-values of the proposed tests analytically. This computational advantage makes our methods practically appealing in large-scale GWASs. We performed simulation studies to show that the proposed tests maintained correct type I error rates, and to compare their powers in various settings with the existing methods. We applied the proposed tests to a GWAS Global Lipids Genetics Consortium summary statistics data set and identified additional genetic variants that were missed by the original single-trait analysis. © 2017, The International Biometric Society.

Coupling Finite Element and Meshless Local Petrov-Galerkin Methods for Two-Dimensional Potential Problems

NASA Technical Reports Server (NTRS)

Chen, T.; Raju, I. S.

2002-01-01

A coupled finite element (FE) method and meshless local Petrov-Galerkin (MLPG) method for analyzing two-dimensional potential problems is presented in this paper. The analysis domain is subdivided into two regions, a finite element (FE) region and a meshless (MM) region. A single weighted residual form is written for the entire domain. Independent trial and test functions are assumed in the FE and MM regions. A transition region is created between the two regions. The transition region blends the trial and test functions of the FE and MM regions. The trial function blending is achieved using a technique similar to the 'Coons patch' method that is widely used in computer-aided geometric design. The test function blending is achieved by using either FE or MM test functions on the nodes in the transition element. The technique was evaluated by applying the coupled method to two potential problems governed by the Poisson equation. The coupled method passed all the patch test problems and gave accurate solutions for the problems studied.

Improved Serodiagnostic Performance for Lyme Disease by Use of Two Recombinant Proteins in Enzyme-Linked Immunosorbent Assay Compared to Standardized Two-Tier Testing.

PubMed

Bradshaw, Gary L; Thueson, R Kelley; Uriona, Todd J

2017-10-01

The most reliable test method for the serological confirmation of Lyme disease (LD) is a 2-tier method recommended by the CDC in 1995. The first-tier test is a low-specificity enzyme-linked immunosorbent assay (ELISA), and the second-tier tests are higher-specificity IgG and IgM Western blots. This study describes the selection of two Borrelia burgdorferi recombinant proteins and evaluation of their performance in a simple 1-tier test for the serological confirmation of LD. These two proteins were generated from (i) the full-length dbpA gene combined with the invariable region 6 of the vlsE gene (DbpA/C6) and (b) the full-length ospC gene (OspC). The expressed DbpA/C6 and OspC proteins were useful in detecting anti- Borrelia IgG and IgM antibodies, respectively. A blind study was conducted on a well-characterized panel of 279 human sera from the CDC, comparing ELISAs using these two recombinant antigens with the 2-tier test method. The two methods (DbpA/C6-OspC versus 2-tier test) were equivalent in identifying sera from negative-control subjects (99% and 100% specificity, respectively) and in detecting stage II and III LD patient sera (100% and 100% sensitivity). However, the DbpA/C6-OspC ELISA was markedly better (80% versus 63%) than the 2-tier test method in detecting anti- Borrelia antibodies in stage I LD patients. The findings suggest that these antigens could be used in a simple 1-tier ELISA that is faster to perform, easier to interpret, and less expensive than the 2-tier test method and which is better at detecting Borrelia -specific antibodies in sera from patients with stage I LD. Copyright © 2017 Bradshaw et al.

Evaluation of the Thermo Scientific SureTect Salmonella species assay. AOAC Performance Tested Method 051303.

PubMed

Cloke, Jonathan; Clark, Dorn; Radcliff, Roy; Leon-Velarde, Carlos; Larson, Nathan; Dave, Keron; Evans, Katharine; Crabtree, David; Hughes, Annette; Simpson, Helen; Holopainen, Jani; Wickstrand, Nina; Kauppinen, Mikko

2014-01-01

The Thermo Scientific SureTect Salmonella species Assay is a new real-time PCR assay for the detection of Salmonellae in food and environmental samples. This validation study was conducted using the AOAC Research Institute (RI) Performance Tested Methods program to validate the SureTect Salmonella species Assay in comparison to the reference method detailed in International Organization for Standardization 6579:2002 in a variety of food matrixes, namely, raw ground beef, raw chicken breast, raw ground pork, fresh bagged lettuce, pork frankfurters, nonfat dried milk powder, cooked peeled shrimp, pasteurized liquid whole egg, ready-to-eat meal containing beef, and stainless steel surface samples. With the exception of liquid whole egg and fresh bagged lettuce, which were tested in-house, all matrixes were tested by Marshfield Food Safety, Marshfield, WI, on behalf of Thermo Fisher Scientific. In addition, three matrixes (pork frankfurters, lettuce, and stainless steel surface samples) were analyzed independently as part of the AOAC-RI-controlled laboratory study by the University of Guelph, Canada. No significant difference by probability of detection or McNemars Chi-squared statistical analysis was found between the candidate or reference methods for any of the food matrixes or environmental surface samples tested during the validation study. Inclusivity and exclusivity testing was conducted with 117 and 36 isolates, respectively, which demonstrated that the SureTect Salmonella species Assay was able to detect all the major groups of Salmonella enterica subspecies enterica (e.g., Typhimurium) and the less common subspecies of S. enterica (e.g., arizoniae) and the rarely encountered S. bongori. None of the exclusivity isolates analyzed were detected by the SureTect Salmonella species Assay. Ruggedness testing was conducted to evaluate the performance of the assay with specific method deviations outside of the recommended parameters open to variation (enrichment time and temperature, and lysis temperature), which demonstrated that the assay gave reliable performance. Accelerated stability testing was additionally conducted, validating the assay shelf life.

In vivo distribution of spinal intervertebral stiffness based on clinical flexibility tests.

PubMed

Lafon, Yoann; Lafage, Virginie; Steib, Jean-Paul; Dubousset, Jean; Skalli, Wafa

2010-01-15

A numerical study was conducted to identify the intervertebral stiffness of scoliotic spines from spinal flexibility tests. To study the intervertebral 3-dimensional (3D) stiffness distribution along scoliotic spine. Few methods have been reported in literature to quantify the in vivo 3D intervertebral stiffness of the scoliotic spine. Based on the simulation of flexibility tests, these methods were operator-dependent and could yield to clinically irrelevant stiffnesses. This study included 30 patients surgically treated for severe idiopathic scoliosis. A previously validated trunk model, with patient-specific geometry, was used to simulate bending tests according to the in vivo displacements of T1 and L5 measured from bending test radiographs. Differences between in vivo and virtual spinal behaviors during bending tests (left and right) were computed in terms of vertebral rotations and translation. An automated method, driven by a priori knowledge, identified intervertebral stiffnesses in order to reproduce the in vivo spinal behavior. Because of the identification of intervertebral stiffnesses, differences between in vivo and virtual spinal displacements were drastically reduced (95% of the differences less than +/-3 mm for vertebral translation). Intervertebral stiffness distribution after identification was analyzed. On convex side test, the intervertebral stiffness of the compensatory curves increased in most cases, whereas the major curve became more flexible. Stiffness singularities were found in junctional zones: these specific levels were predominantly flexible, both in torsion and in lateral bending. The identification of in vivo intervertebral stiffness may improve our understanding of scoliotic spine and the relevance of patient-specific methods for surgical planning.

Quality and Reporting of Diagnostic Accuracy Studies in TB, HIV and Malaria: Evaluation Using QUADAS and STARD Standards

PubMed Central

Fontela, Patricia Scolari; Pant Pai, Nitika; Schiller, Ian; Dendukuri, Nandini; Ramsay, Andrew; Pai, Madhukar

2009-01-01

Background Poor methodological quality and reporting are known concerns with diagnostic accuracy studies. In 2003, the QUADAS tool and the STARD standards were published for evaluating the quality and improving the reporting of diagnostic studies, respectively. However, it is unclear whether these tools have been applied to diagnostic studies of infectious diseases. We performed a systematic review on the methodological and reporting quality of diagnostic studies in TB, malaria and HIV. Methods We identified diagnostic accuracy studies of commercial tests for TB, malaria and HIV through a systematic search of the literature using PubMed and EMBASE (2004–2006). Original studies that reported sensitivity and specificity data were included. Two reviewers independently extracted data on study characteristics and diagnostic accuracy, and used QUADAS and STARD to evaluate the quality of methods and reporting, respectively. Findings Ninety (38%) of 238 articles met inclusion criteria. All studies had design deficiencies. Study quality indicators that were met in less than 25% of the studies included adequate description of withdrawals (6%) and reference test execution (10%), absence of index test review bias (19%) and reference test review bias (24%), and report of uninterpretable results (22%). In terms of quality of reporting, 9 STARD indicators were reported in less than 25% of the studies: methods for calculation and estimates of reproducibility (0%), adverse effects of the diagnostic tests (1%), estimates of diagnostic accuracy between subgroups (10%), distribution of severity of disease/other diagnoses (11%), number of eligible patients who did not participate in the study (14%), blinding of the test readers (16%), and description of the team executing the test and management of indeterminate/outlier results (both 17%). The use of STARD was not explicitly mentioned in any study. Only 22% of 46 journals that published the studies included in this review required authors to use STARD. Conclusion Recently published diagnostic accuracy studies on commercial tests for TB, malaria and HIV have moderate to low quality and are poorly reported. The more frequent use of tools such as QUADAS and STARD may be necessary to improve the methodological and reporting quality of future diagnostic accuracy studies in infectious diseases. PMID:19915664

Study on optimization method of test conditions for fatigue crack detection using lock-in vibrothermography

NASA Astrophysics Data System (ADS)

Min, Qing-xu; Zhu, Jun-zhen; Feng, Fu-zhou; Xu, Chao; Sun, Ji-wei

2017-06-01

In this paper, the lock-in vibrothermography (LVT) is utilized for defect detection. Specifically, for a metal plate with an artificial fatigue crack, the temperature rise of the defective area is used for analyzing the influence of different test conditions, i.e. engagement force, excitation intensity, and modulated frequency. The multivariate nonlinear and logistic regression models are employed to estimate the POD (probability of detection) and POA (probability of alarm) of fatigue crack, respectively. The resulting optimal selection of test conditions is presented. The study aims to provide an optimized selection method of the test conditions in the vibrothermography system with the enhanced detection ability.

Conventional Rapid Latex Agglutination in Estimation of von Willebrand Factor: Method Revisited and Potential Clinical Applications

PubMed Central

Che Hussin, Che Maraina

2014-01-01

Measurement of von Willebrand factor antigen (VWF : Ag) levels is usually performed in a specialised laboratory which limits its application in routine clinical practice. So far, no commercial rapid test kit is available for VWF : Ag estimation. This paper discusses the technical aspect of latex agglutination method which was established to suit the purpose of estimating von Willebrand factor (VWF) levels in the plasma sample. The latex agglutination test can be performed qualitatively and semiquantitatively. Reproducibility, stability, linearity, limit of detection, interference, and method comparison studies were conducted to evaluate the performance of this test. Semiquantitative latex agglutination test was strongly correlated with the reference immunoturbidimetric assay (Spearman's rho = 0.946, P < 0.001, n = 132). A substantial agreement (κ = 0.77) was found between qualitative latex agglutination test and the reference assay. Using the scoring system for the rapid latex test, no agglutination is with 0% VWF : Ag (control negative), 1+ reaction is equivalent to <20% VWF : Ag, and 4+ reaction indicates >150% VWF : Ag (when comparing with immunoturbidimetric assay). The findings from evaluation studies suggest that latex agglutination method is suitable to be used as a rapid test kit for the estimation of VWF : Ag levels in various clinical conditions associated with high levels and low levels of VWF : Ag. PMID:25759835

Methodological Issues in Antifungal Susceptibility Testing of Malassezia pachydermatis

PubMed Central

Peano, Andrea; Pasquetti, Mario; Tizzani, Paolo; Chiavassa, Elisa; Guillot, Jacques; Johnson, Elizabeth

2017-01-01

Reference methods for antifungal susceptibility testing of yeasts have been developed by the Clinical and Laboratory Standards Institute (CLSI) and the European Committee on Antibiotic Susceptibility Testing (EUCAST). These methods are intended to test the main pathogenic yeasts that cause invasive infections, namely Candida spp. and Cryptococcus neoformans, while testing other yeast species introduces several additional problems in standardization not addressed by these reference procedures. As a consequence, a number of procedures have been employed in the literature to test the antifungal susceptibility of Malassezia pachydermatis. This has resulted in conflicting results. The aim of the present study is to review the procedures and the technical parameters (growth media, inoculum preparation, temperature and length of incubation, method of reading) employed for susceptibility testing of M. pachydermatis, and when possible, to propose recommendations for or against their use. Such information may be useful for the future development of a reference assay. PMID:29371554

Use of implantable pellets to administer low levels of methyl mercury to fish

USGS Publications Warehouse

Arnold, B.S.; Jagoe, C.H.; Gross, T.S.

1999-01-01

Implantable pellets of methyl mercury chloride were tested in Nile Tilapia (Oreochromis niloticus) to appraise the effectiveness of the method for chronic studies of mercury. Two dosing regimes of 15 and 1.5 grams/CH3HgCl pellet (test 1) and 1 and 0.1 grams/pellet (test 2-3) of methyl mercury chloride were used in three tests. Additional pellets containing only matrix were used as controls. The pellets were inserted into the peritoneal cavity along with a microchip for identification. Three methods of incision closure: sutures and two types of surgical glue, were tested. Pellets used in test one released the dose too fast, resulting in premature death of the fish. Results from test 2 and 3 show blood mercury concentrations over time and tissue levels at necropsy consistent with dose suggesting that this is a viable method of dosing fish.

Fostering Effective Studying and Study Planning with Study Questions

ERIC Educational Resources Information Center

Wilhelm, Pascal; Pieters, Jules M.

2007-01-01

In a course on biological psychology and neuropsychology, study questions were provided that also appeared as test questions in the course exam. This method was introduced to support students in active processing and reproduction of the study texts, and study planning. Data were gathered to test the hypothesis that study question use would be…

Adaptive Set-Based Methods for Association Testing.

PubMed

Su, Yu-Chen; Gauderman, William James; Berhane, Kiros; Lewinger, Juan Pablo

2016-02-01

With a typical sample size of a few thousand subjects, a single genome-wide association study (GWAS) using traditional one single nucleotide polymorphism (SNP)-at-a-time methods can only detect genetic variants conferring a sizable effect on disease risk. Set-based methods, which analyze sets of SNPs jointly, can detect variants with smaller effects acting within a gene, a pathway, or other biologically relevant sets. Although self-contained set-based methods (those that test sets of variants without regard to variants not in the set) are generally more powerful than competitive set-based approaches (those that rely on comparison of variants in the set of interest with variants not in the set), there is no consensus as to which self-contained methods are best. In particular, several self-contained set tests have been proposed to directly or indirectly "adapt" to the a priori unknown proportion and distribution of effects of the truly associated SNPs in the set, which is a major determinant of their power. A popular adaptive set-based test is the adaptive rank truncated product (ARTP), which seeks the set of SNPs that yields the best-combined evidence of association. We compared the standard ARTP, several ARTP variations we introduced, and other adaptive methods in a comprehensive simulation study to evaluate their performance. We used permutations to assess significance for all the methods and thus provide a level playing field for comparison. We found the standard ARTP test to have the highest power across our simulations followed closely by the global model of random effects (GMRE) and a least absolute shrinkage and selection operator (LASSO)-based test. © 2015 WILEY PERIODICALS, INC.

A two-hour antibiotic susceptibility test by ATP-bioluminescence.

PubMed

March Rosselló, Gabriel Alberto; García-Loygorri Jordán de Urries, María Cristina; Gutiérrez Rodríguez, María Purificación; Simarro Grande, María; Orduña Domingo, Antonio; Bratos Pérez, Miguel Ángel

2016-01-01

The antibiotic susceptibility test (AST) in Clinical Microbiology laboratories is still time-consuming, and most procedures take 24h to yield results. In this study, a rapid antimicrobial susceptibility test using ATP-bioluminescence has been developed. The design of method was performed using five ATCC collection strains of known susceptibility. This procedure was then validated against standard commercial methods on 10 strains of enterococci, 10 staphylococci, 10 non-fermenting gram negative bacilli, and 13 Enterobacteriaceae from patients. The agreement obtained in the sensitivity between the ATP-bioluminescence method and commercial methods (E-test, MicroScan and VITEK2) was 100%. In summary, the preliminary results obtained in this work show that the ATP-bioluminescence method could provide a fast and reliable AST in two hours. Copyright © 2015 Elsevier España, S.L.U. and Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

Giardia cyst destruction: effectiveness of six small-quantity water disinfection methods.

PubMed

Jarroll, E L; Bingham, A K; Meyer, E A

1980-01-01

None of the available chemical methods for disinfecting drinking water has ever been tested for its ability to destory Giardia cysts. We tested the ability of six such methods to act against Giardia, using excystation as the criterion of viability. Two water qualities (cloudy and clear) and two temperatures (3 and 20 degrees C) were tested. At 20 degrees C, using cloudy and clear water, all of the method proved completely effective. However, at 3 degrees C, in cloudy water one method ("saturated" iodine) was less than completely effective, and in clear water four methods (bleach, Globaline, tincture of iodine and "saturated" iodine) failed to destory all of the cysts. The failure of these methods appears to be related to either an insufficient halogen residual or contact time. This study underlines the importance of considering water temperature when employing halogen disinfection methods.

Validation of the ANSR® Listeria Method for Detection of Listeria spp. in Selected Foods.

PubMed

Caballero, Oscar; Alles, Susan; Wendorf, Michael; Gray, R Lucas; Walton, Kayla; Pinkava, Lisa; Mozola, Mark; Rice, Jennifer

2015-01-01

ANSR® Listeria was previously certified as Performance Tested Method(SM) 101202 for detection of Listeria spp. on selected environmental surfaces. This study proposes a matrix extension to the method for detection of Listeria spp. in selected food matrixes. The method is an isothermal nucleic acid amplification assay based on the nicking enzyme amplification reaction technology. Following single-step sample enrichment for 16-24 h, the assay is completed in less than 50 min, requiring only simple instrumentation. Inclusivity testing was performed using a panel of 51 strains of Listeria spp., representing the species L. grayi, L. innocua, L. ivanovii, L. monocytogenes, L. seeligeri, and L. welshimeri. All strains tested were detected by the ANSR assay. Exclusivity testing of 30 strains representing non-Listeria Gram-positive bacteria yielded no evidence of cross-reactivity. Performance of the ANSR method for detection of Listeria spp. was compared to that of reference culture procedures for pasteurized liquid egg, pasteurized 2% milk, Mexican-style cheese, ice cream, smoked salmon, lettuce, cantaloupe, and guacamole. Data obtained in these unpaired studies and analyzed using a probability of detection model demonstrated that there were no statistically significant differences in results between the ANSR and reference culture methods, except for milk at 16 h and cantaloupe. In milk and smoked salmon, ANSR sensitivity was low at 16 h and therefore the recommended incubation time is 24 h. In cantaloupe, ANSR was found to be more sensitive than the reference culture method at both 16 and 24 h in independent laboratory testing. The ANSR Listeria method can be used as an accurate, rapid, and simple alternative to standard culture methods for detection of Listeria spp. in selected food types.

Questions of testing rate and flexibility of rocket test benches, discussed on the basis of the test benches of Nitrochemie GMBH in Aschau

NASA Technical Reports Server (NTRS)

LEGRAND

1987-01-01

The rocket test benches are used to study burnup behavior by various methods. In the first ten months of 1966, 1578 shots were performed to test propellants, and 920 to test 14 thrust and pressure measurement projects.

Comparison of hydraulic conductivities for a sand and gravel aquifer in southeastern Massachusetts, estimated by three methods

USGS Publications Warehouse

Warren, L.P.; Church, P.E.; Turtora, Michael

1996-01-01

Hydraulic conductivities of a sand and gravel aquifer were estimated by three methods: constant- head multiport-permeameter tests, grain-size analyses (with the Hazen approximation method), and slug tests. Sediment cores from 45 boreholes were undivided or divided into two or three vertical sections to estimate hydraulic conductivity based on permeameter tests and grain-size analyses. The cores were collected from depth intervals in the screened zone of the aquifer in each observation well. Slug tests were performed on 29 observation wells installed in the boreholes. Hydraulic conductivities of 35 sediment cores estimated by use of permeameter tests ranged from 0.9 to 86 meters per day, with a mean of 22.8 meters per day. Hydraulic conductivities of 45 sediment cores estimated by use of grain-size analyses ranged from 0.5 to 206 meters per day, with a mean of 40.7 meters per day. Hydraulic conductivities of aquifer material at 29 observation wells estimated by use of slug tests ranged from 0.6 to 79 meters per day, with a mean of 32.9 meters per day. The repeatability of estimated hydraulic conductivities were estimated to be within 30 percent for the permeameter method, 12 percent for the grain-size method, and 9.5 percent for the slug test method. Statistical tests determined that the medians of estimates resulting from the slug tests and grain-size analyses were not significantly different but were significantly higher than the median of estimates resulting from the permeameter tests. Because the permeameter test is the only method considered which estimates vertical hydraulic conductivity, the difference in estimates may be attributed to vertical or horizontal anisotropy. The difference in the average hydraulic conductivities estimated by use of each method was less than 55 percent when compared to the estimated hydraulic conductivity determined from an aquifer test conducted near the study area.

A Generalized Pivotal Quantity Approach to Analytical Method Validation Based on Total Error.

PubMed

Yang, Harry; Zhang, Jianchun

2015-01-01

The primary purpose of method validation is to demonstrate that the method is fit for its intended use. Traditionally, an analytical method is deemed valid if its performance characteristics such as accuracy and precision are shown to meet prespecified acceptance criteria. However, these acceptance criteria are not directly related to the method's intended purpose, which is usually a gurantee that a high percentage of the test results of future samples will be close to their true values. Alternate "fit for purpose" acceptance criteria based on the concept of total error have been increasingly used. Such criteria allow for assessing method validity, taking into account the relationship between accuracy and precision. Although several statistical test methods have been proposed in literature to test the "fit for purpose" hypothesis, the majority of the methods are not designed to protect the risk of accepting unsuitable methods, thus having the potential to cause uncontrolled consumer's risk. In this paper, we propose a test method based on generalized pivotal quantity inference. Through simulation studies, the performance of the method is compared to five existing approaches. The results show that both the new method and the method based on β-content tolerance interval with a confidence level of 90%, hereafter referred to as the β-content (0.9) method, control Type I error and thus consumer's risk, while the other existing methods do not. It is further demonstrated that the generalized pivotal quantity method is less conservative than the β-content (0.9) method when the analytical methods are biased, whereas it is more conservative when the analytical methods are unbiased. Therefore, selection of either the generalized pivotal quantity or β-content (0.9) method for an analytical method validation depends on the accuracy of the analytical method. It is also shown that the generalized pivotal quantity method has better asymptotic properties than all of the current methods. Analytical methods are often used to ensure safety, efficacy, and quality of medicinal products. According to government regulations and regulatory guidelines, these methods need to be validated through well-designed studies to minimize the risk of accepting unsuitable methods. This article describes a novel statistical test for analytical method validation, which provides better protection for the risk of accepting unsuitable analytical methods. © PDA, Inc. 2015.

A new approach to accelerated drug-excipient compatibility testing.

PubMed

Sims, Jonathan L; Carreira, Judith A; Carrier, Daniel J; Crabtree, Simon R; Easton, Lynne; Hancock, Stephen A; Simcox, Carol E

2003-01-01

The purpose of this study was to develop a method of qualitatively predicting the most likely degradants in a formulation or probing specific drug-excipient interactions in a significantly shorter time frame than the typical 1 month storage testing. In the example studied, accelerated storage testing of a solid dosage form at 50 degrees C, the drug substance SB-243213-A degraded via the formation of two oxidative impurities. These impurities reached a level of 1% PAR after 3 months. Various stressing methods were examined to try to recreate this degradation and in doing so provide a practical and reliable method capable of predicting drug-excipient interactions. The technique developed was able to mimic the 1-month's accelerated degradation in just 1 hr. The method was suitable for automated analysis, capable of multisample stressing, and ideal for use in drug-excipient compatibility screening.

[An evaluation of the effectiveness of laboratory diagnostic methods for brucellosis].

PubMed

Gandara, B; Zheludkov, M M; Chernysheva, M I

1994-01-01

The diagnostic value of bacteriological and serological methods for the laboratory diagnosis of brucellosis was studied. In the analysis of milk and cheese specimens Brucella cultures were isolated and differentiated as B.melitensis, biovar I, and B.abortus, biovar 4. In 25.6% of cases B.melitensis culture, biovar 1, was isolated from the blood of persons suspected for brucellosis. The isolation of B.melitensis culture from milk showed that this infective agent migrated from small animals to cattle, which was indicative of a high risk of human infection in the state of Zacatecas, Mexico. The comparative evaluation of serological diagnostic methods (the agglutination test in test tubes, Huddleson's slide test, the acidic rose bengal test and the 2-mercaptoethanol test) showed high sensitivity of rapid tests (Huddleson's test and the rose bengal test in 93.7% and 87.9% of cases respectively). The 2-mercaptoethanol test which gave positive results in 63.8% of cases provided additional information characterizing the course of infections process.

Accelerated in vitro release testing method for naltrexone loaded PLGA microspheres.

PubMed

Andhariya, Janki V; Choi, Stephanie; Wang, Yan; Zou, Yuan; Burgess, Diane J; Shen, Jie

2017-03-30

The objective of the present study was to develop a discriminatory and reproducible accelerated release testing method for naltrexone loaded parenteral polymeric microspheres. The commercially available naltrexone microsphere product (Vivitrol ® ) was used as the testing formulation in the in vitro release method development, and both sample-and-separate and USP apparatus 4 methods were investigated. Following an in vitro drug stability study, frequent media replacement and addition of anti-oxidant in the release medium were used to prevent degradation of naltrexone during release testing at "real-time" (37°C) and "accelerated" (45°C), respectively. The USP apparatus 4 method was more reproducible than the sample-and-separate method. In addition, the accelerated release profile obtained using USP apparatus 4 had a shortened release duration (within seven days), and good correlation with the "real-time" release profile. Lastly, the discriminatory ability of the developed accelerated release method was assessed using compositionally equivalent naltrexone microspheres with different release characteristics. The developed accelerated USP apparatus 4 release method was able to detect differences in the release characteristics of the prepared naltrexone microspheres. Moreover, a linear correlation was observed between the "real-time" and accelerated release profiles of all the formulations investigated, suggesting that the release mechanism(s) may be similar under both conditions. These results indicate that the developed accelerated USP apparatus 4 method has the potential to be an appropriate fast quality control tool for long-acting naltrexone PLGA microspheres. Copyright © 2017 Elsevier B.V. All rights reserved.

Comparison of four methods to assess colostral IgG concentration in dairy cows.

PubMed

Chigerwe, Munashe; Tyler, Jeff W; Middleton, John R; Spain, James N; Dill, Jeffrey S; Steevens, Barry J

2008-09-01

To determine sensitivity and specificity of 4 methods to assess colostral IgG concentration in dairy cows and determine the optimal cutpoint for each method. Cross-sectional study. 160 Holstein dairy cows. 171 composite colostrum samples collected within 2 hours after parturition were used in the study. Test methods used to estimate colostral IgG concentration consisted of weight of the first milking, 2 hydrometers, and an electronic refractometer. Results of the test methods were compared with colostral IgG concentration determined by means of radial immunodiffusion. For each method, sensitivity and specificity for detecting colostral IgG concentration < 50 g/L were calculated across a range of potential cutpoints, and the optimal cutpoint for each test was selected to maximize sensitivity and specificity. At the optimal cutpoint for each method, sensitivity for weight of the first milking (0.42) was significantly lower than sensitivity for each of the other 3 methods (hydrometer 1, 0.75; hydrometer 2, 0.76; refractometer, 0.75), but no significant differences were identified among the other 3 methods with regard to sensitivity. Specificities at the optimal cutpoint were similar for all 4 methods. Results suggested that use of either hydrometer or the electronic refractometer was an acceptable method of screening colostrum for low IgG concentration; however, the manufacturer-defined scale for both hydrometers overestimated colostral IgG concentration. Use of weight of the first milking as a screening test to identify bovine colostrum with inadequate IgG concentration could not be justified because of the low sensitivity.

Comparison between Different Methods for Biomechanical Assessment of Ex Vivo Fracture Callus Stiffness in Small Animal Bone Healing Studies

PubMed Central

Steiner, Malte; Volkheimer, David; Meyers, Nicholaus; Wehner, Tim; Wilke, Hans-Joachim; Claes, Lutz; Ignatius, Anita

2015-01-01

For ex vivo measurements of fracture callus stiffness in small animals, different test methods, such as torsion or bending tests, are established. Each method provides advantages and disadvantages, and it is still debated which of those is most sensitive to experimental conditions (i.e. specimen alignment, directional dependency, asymmetric behavior). The aim of this study was to experimentally compare six different testing methods regarding their robustness against experimental errors. Therefore, standardized specimens were created by selective laser sintering (SLS), mimicking size, directional behavior, and embedding variations of respective rat long bone specimens. For the latter, five different geometries were created which show shifted or tilted specimen alignments. The mechanical tests included three-point bending, four-point bending, cantilever bending, axial compression, constrained torsion, and unconstrained torsion. All three different bending tests showed the same principal behavior. They were highly dependent on the rotational direction of the maximum fracture callus expansion relative to the loading direction (creating experimental errors of more than 60%), however small angular deviations (<15°) were negligible. Differences in the experimental results between the bending tests originate in their respective location of maximal bending moment induction. Compared to four-point bending, three-point bending is easier to apply on small rat and mouse bones under realistic testing conditions and yields robust measurements, provided low variation of the callus shape among the tested specimens. Axial compressive testing was highly sensitive to embedding variations, and therefore cannot be recommended. Although it is experimentally difficult to realize, unconstrained torsion testing was found to be the most robust method, since it was independent of both rotational alignment and embedding uncertainties. Constrained torsional testing showed small errors (up to 16.8%, compared to corresponding alignment under unconstrained torsion) due to a parallel offset between the specimens’ axis of gravity and the torsional axis of rotation. PMID:25781027

Implementation of an Improved Adaptive Testing Theory

ERIC Educational Resources Information Center

Al-A'ali, Mansoor

2007-01-01

Computer adaptive testing is the study of scoring tests and questions based on assumptions concerning the mathematical relationship between examinees' ability and the examinees' responses. Adaptive student tests, which are based on item response theory (IRT), have many advantages over conventional tests. We use the least square method, a…

Multi-reader ROC studies with split-plot designs: a comparison of statistical methods.

PubMed

Obuchowski, Nancy A; Gallas, Brandon D; Hillis, Stephen L

2012-12-01

Multireader imaging trials often use a factorial design, in which study patients undergo testing with all imaging modalities and readers interpret the results of all tests for all patients. A drawback of this design is the large number of interpretations required of each reader. Split-plot designs have been proposed as an alternative, in which one or a subset of readers interprets all images of a sample of patients, while other readers interpret the images of other samples of patients. In this paper, the authors compare three methods of analysis for the split-plot design. Three statistical methods are presented: the Obuchowski-Rockette method modified for the split-plot design, a newly proposed marginal-mean analysis-of-variance approach, and an extension of the three-sample U-statistic method. A simulation study using the Roe-Metz model was performed to compare the type I error rate, power, and confidence interval coverage of the three test statistics. The type I error rates for all three methods are close to the nominal level but tend to be slightly conservative. The statistical power is nearly identical for the three methods. The coverage of 95% confidence intervals falls close to the nominal coverage for small and large sample sizes. The split-plot multireader, multicase study design can be statistically efficient compared to the factorial design, reducing the number of interpretations required per reader. Three methods of analysis, shown to have nominal type I error rates, similar power, and nominal confidence interval coverage, are available for this study design. Copyright © 2012 AUR. All rights reserved.

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

Rowe, M.D.; Pierce, B.L.

This report presents results of tests of different final site selection methods used for siting large-scale facilities such as nuclear power plants. Test data are adapted from a nuclear power plant siting study conducted on Long Island, New York. The purpose of the tests is to determine whether or not different final site selection methods produce different results, and to obtain some understanding of the nature of any differences found. Decision rules and weighting methods are included. Decision rules tested are Weighting Summation, Power Law, Decision Analysis, Goal Programming, and Goal Attainment; weighting methods tested are Categorization, Ranking, Rating Ratiomore » Estimation, Metfessel Allocation, Indifferent Tradeoff, Decision Analysis lottery, and Global Evaluation. Results show that different methods can, indeed, produce different results, but that the probability that they will do so is controlled by the structure of differences among the sites being evaluated. Differences in weights and suitability scores attributable to methods have reduced significance if the alternatives include one or two sites that are superior to all others in many attributes. The more tradeoffs there are among good and bad levels of different attributes at different sites, the more important are the specifics of methods to the final decision. 5 refs., 14 figs., 19 tabs.« less

Evaluation of PDA Technical Report No 33. Statistical Testing Recommendations for a Rapid Microbiological Method Case Study.

PubMed

Murphy, Thomas; Schwedock, Julie; Nguyen, Kham; Mills, Anna; Jones, David

2015-01-01

New recommendations for the validation of rapid microbiological methods have been included in the revised Technical Report 33 release from the PDA. The changes include a more comprehensive review of the statistical methods to be used to analyze data obtained during validation. This case study applies those statistical methods to accuracy, precision, ruggedness, and equivalence data obtained using a rapid microbiological methods system being evaluated for water bioburden testing. Results presented demonstrate that the statistical methods described in the PDA Technical Report 33 chapter can all be successfully applied to the rapid microbiological method data sets and gave the same interpretation for equivalence to the standard method. The rapid microbiological method was in general able to pass the requirements of PDA Technical Report 33, though the study shows that there can be occasional outlying results and that caution should be used when applying statistical methods to low average colony-forming unit values. Prior to use in a quality-controlled environment, any new method or technology has to be shown to work as designed by the manufacturer for the purpose required. For new rapid microbiological methods that detect and enumerate contaminating microorganisms, additional recommendations have been provided in the revised PDA Technical Report No. 33. The changes include a more comprehensive review of the statistical methods to be used to analyze data obtained during validation. This paper applies those statistical methods to analyze accuracy, precision, ruggedness, and equivalence data obtained using a rapid microbiological method system being validated for water bioburden testing. The case study demonstrates that the statistical methods described in the PDA Technical Report No. 33 chapter can be successfully applied to rapid microbiological method data sets and give the same comparability results for similarity or difference as the standard method. © PDA, Inc. 2015.

Olive leaf extract activity against Candida albicans and C. dubliniensis - the in vitro viability study.

PubMed

Zorić, Nataša; Kopjar, Nevenka; Kraljić, Klara; Oršolić, Nada; Tomić, Siniša; Kosalec, Ivan

2016-09-01

Olive leaf extract is characterized by a high content of polyphenols (oleuropein, hydroxytyrosol and their derivatives), which is associated with its therapeutic properties. The objective of the present research was to evaluate the antifungal activity of olive leaf extract against Candida albicans ATCC 10231 and C. dubliniensis CBS 7987 strains. Minimum inhibitory concentrations (MIC) of the extract were determined by several in vitro assays. The extract showed a concentration depended effect on the viability of C. albicans with MIC value of 46.875 mg mL-1 and C. dubliniensis with MIC value 62.5 mg mL-1. Most sensitive methods for testing the antifungal effect of the extracts were the trypan blue exclusion method and fluorescent dye exclusion method while MIC could not be determined by the method according to the EUCAST recommendation suggesting that herbal preparations contain compounds that may interfere with this susceptibility testing. The fluorescent dye exclusion method was also used for the assessment of morphological changes in the nuclei of treated cells. According to the obtained results, olive leaf extract is less effective against the tested strains than hydroxytyrosol, an olive plant constituent tested in our previous study.

Acoustic Treatment Design Scaling Methods. Volume 1; Overview, Results, and Recommendations

NASA Technical Reports Server (NTRS)

Kraft, R. E.; Yu, J.

1999-01-01

Scale model fan rigs that simulate new generation ultra-high-bypass engines at about 1/5-scale are achieving increased importance as development vehicles for the design of low-noise aircraft engines. Testing at small scale allows the tests to be performed in existing anechoic wind tunnels, which provides an accurate simulation of the important effects of aircraft forward motion on the noise generation. The ability to design, build, and test miniaturized acoustic treatment panels on scale model fan rigs representative of the fullscale engine provides not only a cost-savings, but an opportunity to optimize the treatment by allowing tests of different designs. The primary objective of this study was to develop methods that will allow scale model fan rigs to be successfully used as acoustic treatment design tools. The study focuses on finding methods to extend the upper limit of the frequency range of impedance prediction models and acoustic impedance measurement methods for subscale treatment liner designs, and confirm the predictions by correlation with measured data. This phase of the program had as a goal doubling the upper limit of impedance measurement from 6 kHz to 12 kHz. The program utilizes combined analytical and experimental methods to achieve the objectives.

Experiments of the selection of a method evaluating the fire resistance of some materials based on macromolecular compounds

NASA Technical Reports Server (NTRS)

Stoica, Steln; Sebe, Mircea Octavian

1987-01-01

A comparative experimental study on the application of various tests for the evaluation of the fire-resistant properties of plastic materials is presented. On the basis of the results obtained conclusions are drawn on the advantages and disadvantages of the methods used, and a preferred test method is picked, i.e., the introduction of fire retardant materials into the polymers.

A novel method for single sample multi-axial nanoindentation of hydrated heterogeneous tissues based on testing great white shark jaws.

PubMed

Ferrara, Toni L; Boughton, Philip; Slavich, Eve; Wroe, Stephen

2013-01-01

Nanomechanical testing methods that are suitable for a range of hydrated tissues are crucial for understanding biological systems. Nanoindentation of tissues can provide valuable insights into biology, tissue engineering and biomimetic design. However, testing hydrated biological samples still remains a significant challenge. Shark jaw cartilage is an ideal substrate for developing a method to test hydrated tissues because it is a unique heterogeneous composite of both mineralized (hard) and non-mineralized (soft) layers and possesses a jaw geometry that is challenging to test mechanically. The aim of this study is to develop a novel method for obtaining multidirectional nanomechanical properties for both layers of jaw cartilage from a single sample, taken from the great white shark (Carcharodon carcharias). A method for obtaining multidirectional data from a single sample is necessary for examining tissue mechanics in this shark because it is a protected species and hence samples may be difficult to obtain. Results show that this method maintains hydration of samples that would otherwise rapidly dehydrate. Our study is the first analysis of nanomechanical properties of great white shark jaw cartilage. Variation in nanomechanical properties were detected in different orthogonal directions for both layers of jaw cartilage in this species. The data further suggest that the mineralized layer of shark jaw cartilage is less stiff than previously posited. Our method allows multidirectional nanomechanical properties to be obtained from a single, small, hydrated heterogeneous sample. Our technique is therefore suitable for use when specimens are rare, valuable or limited in quantity, such as samples obtained from endangered species or pathological tissues. We also outline a method for tip-to-optic calibration that facilitates nanoindentation of soft biological tissues. Our technique may help address the critical need for a nanomechanical testing method that is applicable to a variety of hydrated biological materials whether soft or hard.

Nanoparticle filtration performance of NIOSH-certified particulate air-purifying filtering facepiece respirators: evaluation by light scattering photometric and particle number-based test methods.

PubMed

Rengasamy, Samy; Eimer, Benjamin C

2012-01-01

National Institute for Occupational Safety and Health (NIOSH) certification test methods employ charge neutralized NaCl or dioctyl phthalate (DOP) aerosols to measure filter penetration levels of air-purifying particulate respirators photometrically using a TSI 8130 automated filter tester at 85 L/min. A previous study in our laboratory found that widely different filter penetration levels were measured for nanoparticles depending on whether a particle number (count)-based detector or a photometric detector was used. The purpose of this study was to better understand the influence of key test parameters, including filter media type, challenge aerosol size range, and detector system. Initial penetration levels for 17 models of NIOSH-approved N-, R-, and P-series filtering facepiece respirators were measured using the TSI 8130 photometric method and compared with the particle number-based penetration (obtained using two ultrafine condensation particle counters) for the same challenge aerosols generated by the TSI 8130. In general, the penetration obtained by the photometric method was less than the penetration obtained with the number-based method. Filter penetration was also measured for ambient room aerosols. Penetration measured by the TSI 8130 photometric method was lower than the number-based ambient aerosol penetration values. Number-based monodisperse NaCl aerosol penetration measurements showed that the most penetrating particle size was in the 50 nm range for all respirator models tested, with the exception of one model at ~200 nm size. Respirator models containing electrostatic filter media also showed lower penetration values with the TSI 8130 photometric method than the number-based penetration obtained for the most penetrating monodisperse particles. Results suggest that to provide a more challenging respirator filter test method than what is currently used for respirators containing electrostatic media, the test method should utilize a sufficient number of particles <100 nm and a count (particle number)-based detector.

Alternative methods for toxicity assessments in fish: comparison of the fish embryo toxicity and the larval growth and survival tests in zebrafish and fathead minnows.

PubMed

Jeffries, Marlo K Sellin; Stultz, Amy E; Smith, Austin W; Rawlings, Jane M; Belanger, Scott E; Oris, James T

2014-11-01

An increased demand for chemical toxicity evaluations has resulted in the need for alternative testing strategies that address animal welfare concerns. The fish embryo toxicity (FET) test developed for zebrafish (Danio rerio) is one such alternative, and the application of the FET test to other species such as the fathead minnow (Pimephales promelas) has been proposed. In the present study, the performances of the FET test and the larval growth and survival (LGS; a standard toxicity testing method) test in zebrafish and fathead minnows were evaluated. This required that testing methods for the fathead minnow FET and zebrafish LGS tests be harmonized with existing test methods and that the performance of these testing strategies be evaluated by comparing the median lethal concentrations of 2 reference toxicants, 3,4-dicholoraniline and ammonia, obtained via each of the test types. The results showed that procedures for the zebrafish FET test can be adapted and applied to the fathead minnow. Differences in test sensitivity were observed for 3,4-dicholoraniline but not ammonia; therefore, conclusions regarding which test types offer the least or most sensitivity could not be made. Overall, these results show that the fathead minnow FET test has potential as an alternative toxicity testing strategy and that further analysis with other toxicants is warranted in an effort to better characterize the sensitivity and feasibility of this testing strategy. © 2014 SETAC.

Relationship between Study Habits and Test Anxiety of Higher Secondary Students

ERIC Educational Resources Information Center

Lawrence, Arul A. S.

2014-01-01

The present study aims to probe the relationship between study habits and test anxiety of higher secondary students. In this normative study survey method was employed. The population for the present study consisted of higher secondary students studying in Tirunelveli district. The investigator used the simple random sampling technique. The sample…

Evaluation of Cortez OneStep Chlamydia Rapicard™ Insta Test for the Detection of Chlamydia trachomatis in Pregnant Women at Mbare Polyclinic in Harare, Zimbabwe.

PubMed

Stephen, Stephen; Muchaneta-Kubara, Chiwoneso Gwyneth Elizabeth; Munjoma, Marshall Wesley; Mandozana, Gibson

2017-01-01

Cervical chlamydia infection poses high risk of pregnancy complications and neonatal infection. Reference methods for the detection of chlamydia infection are not available for routine use in developing countries. Point-of-care (POC) tests can bridge this gap. This study evaluated Cortez Onestep Chlamydia Rapicard™ insta test for the detection of Chlamydia trachomatis in pregnant women at Mbare Polyclinic and determined the prevalence of C. trachomatis . This was a cross sectional study in 242 pregnant women aged ≥18 years attending their first ANC visit at Mbare polyclinic in Harare, Zimbabwe. Data collection form was used to obtain demographic and predisposing factors to Chlamydia infection and two endocervical swabs were collected from each patient. One specimen was examined by the POC test at the clinic and the other by SDA method in the laboratory. The sensitivity, specificity, positive and negative predictive values of the rapid kit were 71.4%, 99.6%, 90.9% and 98.3% respectively. Prevalence of C. trachomitis was 5.8% by SDA method. The kit's sensitivity (71.4%) and specificity (99.6%) implies that the rapid test is an important test which needs further evaluations. The prevalence of C. trichomitis of 5.8% is comparable to studies done elsewhere in Africa.

Laboratory-based testing to evaluate abuse-deterrent formulations and satisfy the Food and Drug Administration's recommendation for Category 1 Testing.

PubMed

Altomare, Christopher; Kinzler, Eric R; Buchhalter, August R; Cone, Edward J; Costantino, Anthony

The US Food and Drug Administration (FDA) considers the development of abuse-deterrent formulations of solid oral dosage forms a public health priority and has outlined a series of premarket studies that should be performed prior to submitting an application to the Agency. Category 1 studies are performed to characterize whether the abuse-deterrent properties of a new formulation can be easily defeated. Study protocols are designed to evaluate common abuse patterns of prescription medications as well as more advanced methods that have been reported on drug abuse websites and forums. Because FDA believes Category 1 testing should fully characterize the abuse-deterrent characteristics of an investigational formulation, Category 1 testing is time consuming and requires specialized laboratory resources as well as advanced knowledge of prescription medication abuse. Recent Advisory Committee meetings at FDA have shown that Category 1 tests play a critical role in FDA's evaluation of an investigational formulation. In this article, we will provide a general overview of the methods of manipulation and routes of administration commonly utilized by prescription drug abusers, how those methods and routes are evaluated in a laboratory setting, and discuss data intake, analysis, and reporting to satisfy FDA's Category 1 testing requirements.

Studies with the USF/NASA toxicity screening test method - Exercise wheels and oxygen replenishment

NASA Technical Reports Server (NTRS)

Hilado, C. J.; Cumming, H. J.

1977-01-01

Continuing efforts to improve the University of San Francisco/NASA toxicity screening test method have included the addition of exercise wheels to provide a different measure of incapacitation, and oxygen replenishment to offset any effect of oxygen depletion by the test animals. The addition of exercise wheels limited the number of animals in each test and doubled the required number of tests without any significant improvement in reproducibility. Oxygen replenishment appears to have an effect on survival in the last 5 minutes of the 30-minute test, but the effect is expected to be similar for most materials.

Evaluation of Enterococcus faecalis clinical isolates with 'penicillin-resistant, ampicillin-susceptible' phenotype as reported by Vitek-2 Compact system.

PubMed

Tan, Yen Ee; Ng, Lily S Y; Tan, Thean Yen

2014-10-01

It has been recently reported that ampicillin susceptibility cannot accurately predict piperacillin and imipenem susceptibilities in penicillin-resistant, ampicillin-susceptible (Pen-R, Amp-S) Enterococcus faecalis isolates, contrary to the current Clinical and Laboratory Standards Institute (CLSI) recommendations. This has important therapeutic implications. Such isolates were noted after the use of Vitek-2 Compact system AST-GP67 susceptibility cards in a Singapore general hospital and they were increasing in numbers. The primary aim of this study was to evaluate these clinical isolates against microbroth dilution (MBD) technique and other commonly used antimicrobial susceptibility test (AST) methods for penicillin and ampicillin. The secondary aim was to evaluate whether ampicillin susceptibility could indeed be a reliable surrogate marker for piperacillin and imipenem susceptibilities in E. faecalis isolates that were confirmed Pen-R, Amp-S.From 2009 to 2013, a total of 49 isolates (5%) of 983 non-duplicate E. faecalis tested by Vitek-2 displayed the 'Pen-R, Amp-S' phenotype in a general hospital in Singapore. These were tested against MBD which was the reference method, Etest and disc diffusion for penicillin and ampicillin. Susceptibilities to piperacillin and imipenem were also tested using MBD. In addition, β-lactamase production test was performed. Forty E. faecalis isolates with penicillin-susceptible, ampicillin-susceptible (Pen-S, Amp-S) phenotype were included for comparative purposes.The categorical agreement rate was 100% for all AST methods in ampicillin reporting for the 'Pen-R, Amp-S' group of E. faecalis isolates. However, a large number of isolates (46 isolates, 93.9%) fell into the major error category for penicillin testing by the Vitek-2 system. Penicillin minimum inhibitory concentrations (MICs) generated by the Vitek-2 system for the majority of these isolates were two doubling dilutions higher compared to those obtained by the reference test. The Etest method correlated well with the MBD method. Thirty-two isolates (65.3%) were in categorical agreement with the MBD method when tested by the disc diffusion method for penicillin. Only three E. faecalis isolates (6.1%) were confirmed to have the uncommon penicillin resistance phenotype, with two of them showing resistance to piperacillin and intermediate to imipenem. β-lactamase production test was negative for all isolates. Among the Pen-S, Amp-S E. faecalis isolates, the categorical agreement was 100% for penicillin and ampicillin in all the tested methods.Enterococcus faecalis with 'Pen-R, Amp-S' phenotype reported by the Vitek-2 system using AST-GP67 susceptibility cards must be confirmed with a reference test, the Etest method being a good alternative. The Vitek-2 system generated higher penicillin MIC readings compared to MBD in this study. The actual prevalence of this uncommon penicillin resistance phenotype in E. faecalis was found to be low in this institution. More studies are required to confirm the reliability of ampicillin as a surrogate marker for piperacillin and imipenem susceptibilities in these isolates.

A simple screening test for the detection of metallo-β-lactamase-producing Pseudomonas aeruginosa and Acinetobacter in a tertiary care hospital.

PubMed

Wan Nor Amilah, W A W; Noor Izani, N J; Ng, W K; Ashraful Haq, J

2012-12-01

Clinical utilization of carbapenems remains under threat with the emergence of acquired carbapenemase-producing bacteria, particularly metallo-β-lactamases (MBL). Rapid detection of MBL-producing Gram-negative bacilli is essential to prevent their widespread dissemination. However, no standardized detection method is available for routine laboratory use. The purpose of the study was to evaluate a chelating-agent based double disk synergic test and disk potentiation test for MBL-producing strain detection and to determine the isolation rate of MBL-producing Pseudomonas aeruginosa and Acinetobacter from clinical samples in our tertiary teaching hospital. A total of 22 and 66 imipenem-resistant P. aeruginosa and Acinetobacter isolates respectively were tested with ceftazidime (CAZ) disk by modified double disk synergic test and disk potentiation test using ethylenediaminetetraacetic acid (EDTA) and 2-mercaptopropionic acid (as chelating agents) to detect MBL production. The tests were compared with EDTA-phenanthroline-imipenem (EPI) microdilution MIC test as gold standard. MBL positive strains were detected in 17 (77.3%) P. aeruginosa and 2 (3.5%) Acinetobacter isolates. The disk potentiation test with 2-mercaptopropionic acid (2-MPA) dilution of 1:12 provided the most acceptable sensitivities and specificities (88.2% sensitivity and 100% specificity in P. aeruginosa; 100% sensitivity and specificity in Acinetobacter) compared to other screening methods used in this study. This study provided useful information on the local prevalence of MBL-producing P. aeruginosa and Acinetobacter in our hospital. Disc potentiation test with CAZ/2-MPA disc appears to be reliable and convenient MBL detection method in the routine clinical laboratory.

Methanogenic activity tests by Infrared Tunable Diode Laser Absorption Spectroscopy.

PubMed

Martinez-Cruz, Karla; Sepulveda-Jauregui, Armando; Escobar-Orozco, Nayeli; Thalasso, Frederic

2012-10-01

Methanogenic activity (MA) tests are commonly carried out to estimate the capability of anaerobic biomass to treat effluents, to evaluate anaerobic activity in bioreactors or natural ecosystems, or to quantify inhibitory effects on methanogenic activity. These activity tests are usually based on the measurement of the volume of biogas produced by volumetric, pressure increase or gas chromatography (GC) methods. In this study, we present an alternative method for non-invasive measurement of methane produced during activity tests in closed vials, based on Infrared Tunable Diode Laser Absorption Spectroscopy (MA-TDLAS). This new method was tested during model acetoclastic and hydrogenotrophic methanogenic activity tests and was compared to a more traditional method based on gas chromatography. From the results obtained, the CH(4) detection limit of the method was estimated to 60 ppm and the minimum measurable methane production rate was estimated to 1.09(.)10(-3) mg l(-1) h(-1), which is below CH(4) production rate usually reported in both anaerobic reactors and natural ecosystems. Additionally to sensitivity, the method has several potential interests compared to more traditional methods among which short measurements time allowing the measurement of a large number of MA test vials, non-invasive measurements avoiding leakage or external interferences and similar cost to GC based methods. It is concluded that MA-TDLAS is a promising method that could be of interest not only in the field of anaerobic digestion but also, in the field of environmental ecology where CH(4) production rates are usually very low. Copyright © 2012 Elsevier B.V. All rights reserved.

The sensitivity of relative toxicity rankings by the USF/NASA test method to some test variables

NASA Technical Reports Server (NTRS)

Hilado, C. J.; Labossiere, L. A.; Leon, H. A.; Kourtides, D. A.; Parker, J. A.; Hsu, M.-T. S.

1976-01-01

Pyrolysis temperature and the distance between the source and sensor of effluents are two important variables in tests for relative toxicity. Modifications of the USF/NASA toxicity screening test method to increase the upper temperature limit of pyrolysis, reduce the distance between the sample and the test animals, and increase the chamber volume available for animal occupancy, did not significantly alter rankings of relative toxicity of four representative materials. The changes rendered some differences no longer significant, but did not reverse any rankings. The materials studied were cotton, wool, aromatic polyamide, and polybenzimidazole.

A stochastic visco-hyperelastic model of human placenta tissue for finite element crash simulations.

PubMed

Hu, Jingwen; Klinich, Kathleen D; Miller, Carl S; Rupp, Jonathan D; Nazmi, Giseli; Pearlman, Mark D; Schneider, Lawrence W

2011-03-01

Placental abruption is the most common cause of fetal deaths in motor-vehicle crashes, but studies on the mechanical properties of human placenta are rare. This study presents a new method of developing a stochastic visco-hyperelastic material model of human placenta tissue using a combination of uniaxial tensile testing, specimen-specific finite element (FE) modeling, and stochastic optimization techniques. In our previous study, uniaxial tensile tests of 21 placenta specimens have been performed using a strain rate of 12/s. In this study, additional uniaxial tensile tests were performed using strain rates of 1/s and 0.1/s on 25 placenta specimens. Response corridors for the three loading rates were developed based on the normalized data achieved by test reconstructions of each specimen using specimen-specific FE models. Material parameters of a visco-hyperelastic model and their associated standard deviations were tuned to match both the means and standard deviations of all three response corridors using a stochastic optimization method. The results show a very good agreement between the tested and simulated response corridors, indicating that stochastic analysis can improve estimation of variability in material model parameters. The proposed method can be applied to develop stochastic material models of other biological soft tissues.

VoIP Accessibility: A Usability Study of Voice over Internet Protocol (VoIP) Systems and A Survey of VoIP Users with Vision Loss

ERIC Educational Resources Information Center

Packer, Jaclyn; Reuschel, William

2018-01-01

Introduction: Accessibility of Voice over Internet Protocol (VoIP) systems was tested with a hands-on usability study and an online survey of VoIP users who are visually impaired. The survey examined the importance of common VoIP features, and both methods assessed difficulty in using those features. Methods: The usability test included four paid…

Study on cord/rubber interface at elevated temperatures by H-pull test method

NASA Astrophysics Data System (ADS)

Jamshidi, M.; Afshar, F.; Mohammadi, N.; Pourmahdian, S.

2005-08-01

Cords are used as reinforcing materials in rubber compounds. To increase cord/rubber interfacial adhesion, they are coated by an adhesive (usually based on resorcinol-formaldehyde-latex). These composites are used in many sectors such as tire and belt industries. Cord/rubber adhesion strength is an important aspect to determine the durability of system. Due to temperature increase during running tires, the adhesion energy becomes different from initial one. To study cord/rubber interface at elevated temperatures, H-adhesion test method was used. H-pull test is a simple method for adhesion evaluation at ambient temperature, so it is usually used for material quality control. In this research, cord/rubber systems were vulcanized at different temperatures and H-adhesion of samples were evaluated at elevated temperatures. Also cord/rubber interface was studied by ATR analyze to determine interfacial interactions kind.

Testing the Intervention Effect in Single-Case Experiments: A Monte Carlo Simulation Study

ERIC Educational Resources Information Center

Heyvaert, Mieke; Moeyaert, Mariola; Verkempynck, Paul; Van den Noortgate, Wim; Vervloet, Marlies; Ugille, Maaike; Onghena, Patrick

2017-01-01

This article reports on a Monte Carlo simulation study, evaluating two approaches for testing the intervention effect in replicated randomized AB designs: two-level hierarchical linear modeling (HLM) and using the additive method to combine randomization test "p" values (RTcombiP). Four factors were manipulated: mean intervention effect,…

Cognitive Process Modeling of Spatial Ability: The Assembling Objects Task

ERIC Educational Resources Information Center

Ivie, Jennifer L.; Embretson, Susan E.

2010-01-01

Spatial ability tasks appear on many intelligence and aptitude tests. Although the construct validity of spatial ability tests has often been studied through traditional correlational methods, such as factor analysis, less is known about the cognitive processes involved in solving test items. This study examines the cognitive processes involved in…

A systematic review and meta-analysis of the diagnostic accuracy of point-of-care tests for the detection of hyperketonemia in dairy cows.

PubMed

Tatone, Elise H; Gordon, Jessica L; Hubbs, Jessie; LeBlanc, Stephen J; DeVries, Trevor J; Duffield, Todd F

2016-08-01

Several rapid tests for use on farm have been validated for the detection of hyperketonemia (HK) in dairy cattle, however the reported sensitivity and specificity of each method varies and no single study has compared them all. Meta-analysis of diagnostic test accuracy is becoming more common in human medical literature but there are few veterinary examples. The objective of this work was to perform a systematic review and meta-analysis to determine the point-of-care testing method with the highest combined sensitivity and specificity, the optimal threshold for each method, and to identify gaps in the literature. A comprehensive literature search resulted in 5196 references. After removing duplicates and performing relevance screening, 23 studies were included for the qualitative synthesis and 18 for the meta-analysis. The three index tests evaluated in the meta-analysis were: the Precision Xtra(®) handheld device measuring beta-hydroxybutyrate (BHB) concentration in whole blood, and Ketostix(®) and KetoTest(®) semi-quantitative strips measuring the concentration of acetoacetate in urine and BHB in milk, respectively. The diagnostic accuracy of the 3 index tests relative to the reference standard measurement of BHB in serum or whole blood between 1.0-1.4mmol/L was compared using the hierarchical summary receiver operator characteristic (HSROC) method. Subgroup analysis was conducted for each index test to examine the accuracy at different thresholds. The impact of the reference standard threshold, the reference standard method, the prevalence of HK in the population, the primary study source and risk of bias of the primary study was explored using meta-regression. The Precision Xtra(®) device had the highest summary sensitivity in whole blood BHB at 1.2mmol/L, 94.8% (CI95%: 92.6-97.0), and specificity, 97.5% (CI95%: 96.9-98.1). The threshold employed (1.2-1.4mmol/L) did not impact the diagnostic accuracy of the test. The Ketostix(®) and KetoTest(®) strips had the highest summary sensitivity and specificity when the trace and weak positive thresholds were used, respectively. Controlling for the source of publication, HK prevalence and reference standard employed did not impact the estimated sensitivity and specificity of the tests. Including only peer-reviewed studies reduced the number of primary studies evaluating the Precision Xtra(®) by 43% and Ketostix(®) by 33%. Diagnosing HK with blood, urine or milk are valid options, however, the diagnostic inaccuracy of urine and milk should be considered when making economic and treatment decisions. Copyright © 2016 Elsevier B.V. All rights reserved.

Comparison of formula and number-right scoring in undergraduate medical training: a Rasch model analysis.

PubMed

Cecilio-Fernandes, Dario; Medema, Harro; Collares, Carlos Fernando; Schuwirth, Lambert; Cohen-Schotanus, Janke; Tio, René A

2017-11-09

Progress testing is an assessment tool used to periodically assess all students at the end-of-curriculum level. Because students cannot know everything, it is important that they recognize their lack of knowledge. For that reason, the formula-scoring method has usually been used. However, where partial knowledge needs to be taken into account, the number-right scoring method is used. Research comparing both methods has yielded conflicting results. As far as we know, in all these studies, Classical Test Theory or Generalizability Theory was used to analyze the data. In contrast to these studies, we will explore the use of the Rasch model to compare both methods. A 2 × 2 crossover design was used in a study where 298 students from four medical schools participated. A sample of 200 previously used questions from the progress tests was selected. The data were analyzed using the Rasch model, which provides fit parameters, reliability coefficients, and response option analysis. The fit parameters were in the optimal interval ranging from 0.50 to 1.50, and the means were around 1.00. The person and item reliability coefficients were higher in the number-right condition than in the formula-scoring condition. The response option analysis showed that the majority of dysfunctional items emerged in the formula-scoring condition. The findings of this study support the use of number-right scoring over formula scoring. Rasch model analyses showed that tests with number-right scoring have better psychometric properties than formula scoring. However, choosing the appropriate scoring method should depend not only on psychometric properties but also on self-directed test-taking strategies and metacognitive skills.

When Your Brother or Sister Has Cancer: A Guide for Teens

MedlinePlus

... can be given as pills, through an injection (shot), or through an intravenous (IV) line. It is ... research study that tests how well new medical approaches work in people. These studies test new methods ...

[Performance evaluation of a fluorescamine-HPLC method for determination of histamine in fish and fish products].

PubMed

Kikuchi, Hiroyuki; Tsutsumi, Tomoaki; Matsuda, Rieko

2012-01-01

A method for the quantification of histamine in fish and fish products using tandem solid-phase extraction and fluorescence derivatization with fluorescamine was previously developed. In this study, we improved this analytical method to develop an official test method for quantification of histamine in fish and fish products, and performed a single laboratory study to validate it. Recovery tests of histamine from fillet (Thunnus obesus), and two fish products (fish sauce and salted and dried whole big-eye sardine) that were spiked at the level of 25 and 50 µg/g for T. obesus, and 50 and 100 µg/g for the two fish products, were carried out. The recoveries of histamine from the three samples tested were 88.8-99.6% with good repeatability (1.3-2.1%) and reproducibility (2.1-4.7%). Therefore, this method is acceptable for the quantification of histamine in fish and fish products. Moreover, surveillance of histamine content in food on the market was conducted using this method, and high levels of histamine were detected in some fish products.

Application of the digital image correlation method in the study of cohesive coarse soil deformations

NASA Astrophysics Data System (ADS)

Kogut, Janusz P.; Tekieli, Marcin

2018-04-01

Non-contact video measurement methods are used to extend the capabilities of standard measurement systems, based on strain gauges or accelerometers. In most cases, they are able to provide more accurate information about the material or construction being tested than traditional sensors, while maintaining a high resolution and measurement stability. With the use of optical methods, it is possible to generate a full field of displacement on the surface of the test sample. The displacement value is the basic (primary) value determined using optical methods, and it is possible to determine the size of the derivative in the form of a sample deformation. This paper presents the application of a non-contact optical method to investigate the deformation of coarse soil material. For this type of soil, it is particularly difficult to obtain basic strength parameters. The use of a non-contact optical method, followed by a digital image correlation (DIC) study of the sample obtained during the tests, effectively completes the description of the behaviour of this type of material.

Finding differentially expressed genes in high dimensional data: Rank based test statistic via a distance measure.

PubMed

Mathur, Sunil; Sadana, Ajit

2015-12-01

We present a rank-based test statistic for the identification of differentially expressed genes using a distance measure. The proposed test statistic is highly robust against extreme values and does not assume the distribution of parent population. Simulation studies show that the proposed test is more powerful than some of the commonly used methods, such as paired t-test, Wilcoxon signed rank test, and significance analysis of microarray (SAM) under certain non-normal distributions. The asymptotic distribution of the test statistic, and the p-value function are discussed. The application of proposed method is shown using a real-life data set. © The Author(s) 2011.

The effect of four-phase teaching method on midwifery students’ emotional intelligence in managing the childbirth

PubMed Central

Mohamadirizi, Soheila; Fahami, Fariba; Bahadoran, Parvin; Ehsanpour, Soheila

2015-01-01

Background: An active teaching method has been used widely in medical education. The aim of this study was to determine the effectiveness of the four-phase teaching method on midwifery students’ emotional intelligence (EQ) in managing the childbirth. Materials and Methods: This was an experimental study that performed in 2013 in Isfahan University of Medical Sciences. Thirty midwifery students were involved in this study and selected through a random sampling method. The EQ questionnaire (43Q) was completed by both the groups, before and after the education. The collected data were analyzed using SPSS 14, the independent t-test, and the paired t-test. The statistically significant level was considered to be <0.05. Results: The findings of the independent t-test did not show any significant difference between EQ scores of the experimental and the control group before the intervention, whereas a statistically significant difference was observed after the intervention between the scores of two groups (P = 0.009). The paired t-test showed a statistically significant difference in EQ scores in the two groups after the intervention in the four-phase and the control group, respectively, as P = 0.005 and P = 0.018. Furthermore, the rate of self-efficiency has increased in the experimental group and control group as 66% and 13% (P = 0.024), respectively. Conclusion: The four-phase teaching method can increase the EQ levels of midwifery students. Therefore, the conduction of this educational model is recommended as an effective learning method. PMID:26097861

Graphical method for comparative statistical study of vaccine potency tests.

PubMed

Pay, T W; Hingley, P J

1984-03-01

Producers and consumers are interested in some of the intrinsic characteristics of vaccine potency assays for the comparative evaluation of suitable experimental design. A graphical method is developed which represents the precision of test results, the sensitivity of such results to changes in dosage, and the relevance of the results in the way they reflect the protection afforded in the host species. The graphs can be constructed from Producer's scores and Consumer's scores on each of the scales of test score, antigen dose and probability of protection against disease. A method for calculating these scores is suggested and illustrated for single and multiple component vaccines, for tests which do or do not employ a standard reference preparation, and for tests which employ quantitative or quantal systems of scoring.

Development of a new test cell to measure cumulative permeation of water-insoluble pesticides with low vapor pressure through protective clothing and glove materials

PubMed Central

SHAW, Anugrah; COLEONE-CARVALHO, Ana Carla; HOLLINGSHURST, Julien; DRAPER, Michael; MACHADO NETO, Joaquim Gonçalves

2017-01-01

A collaborative approach, involving resources and expertise from several countries, was used to develop a test cell to measure cumulative permeation by a solid-state collection technique. The new technique was developed to measure the permeation of pesticide active ingredients and other chemicals with low vapor pressure that would otherwise be difficult to test via standard techniques. The development process is described and the results from the final chosen test method are reported. Inter-laboratory studies were conducted to further refine the new method and determine repeatability and reliability. The revised test method has been approved as a new ISO/EN standard to measure permeation of chemicals with low vapor pressure and/or solubility in water. PMID:29033403

Online Social Networking for HIV Education and Prevention: A Mixed Methods Analysis

PubMed Central

Young, Sean D.; Jaganath, Devan

2013-01-01

Background The purpose of this study is to use mixed (qualitative/quantitative) methods to determine 1) the feasibility and acceptability of using online social networking to facilitate HIV-related discussions, and 2) the relationship between HIV-related online discussions and requests for a home-based HIV testing kit, among men who have sex with men (MSM). Methods Participants, primarily African American and Latino, were invited to join a “secret” group on the social networking website, Facebook. Peer leaders, trained in HIV prevention, posted HIV-related content. Participants were not obligated to respond to discussions or remain within the group. Participant public group conversations were qualitatively and thematically analyzed. Quantitative methods tested associations between qualitative data, participants’ demographic information, and likelihood of requesting a home-based HIV testing kit. Results Latino and African-American participants (N=57) voluntarily used Facebook to discuss the following HIV-related topics (N=485 conversations): Prevention and Testing; Knowledge; Stigma; and Advocacy. Older participants more frequently discussed Prevention and Testing, Stigma, and Advocacy, though younger participants more frequently discussed HIV Knowledge-related conversations. As the study progressed, the proportion of messages related to Prevention and Testing and HIV Stigma increased. Multivariate analysis showed that participants posting about HIV Prevention and Testing (compared to those who did not) were significantly more likely to request an HIV testing kit (OR 11.14, p = 0.001). Conclusions Facebook can serve as an innovative forum to increase both HIV prevention discussions and HIV testing requests among at-risk groups. PMID:23324979

A Latent Class Approach to Estimating Test-Score Reliability

ERIC Educational Resources Information Center

van der Ark, L. Andries; van der Palm, Daniel W.; Sijtsma, Klaas

2011-01-01

This study presents a general framework for single-administration reliability methods, such as Cronbach's alpha, Guttman's lambda-2, and method MS. This general framework was used to derive a new approach to estimating test-score reliability by means of the unrestricted latent class model. This new approach is the latent class reliability…