Home About us Contact
|
Home About us Contact | ||
|
|
||
Test Procedure (test + procedure)
Selected AbstractsAn Adaptive Hierarchical Test Procedure for Selecting Safe and Efficient TreatmentsBIOMETRICAL JOURNAL, Issue 4 2006Franz König Abstract We consider the situation where during a multiple treatment (dose) control comparison high doses are truncated because of lack of safety and low doses are truncated because of lack of efficacy, e.g., by decisions of a data safety monitoring committee in multiple interim looks. We investigate the properties of a hierarchical test procedure for the efficacy outcome in the set of doses carried on until the end of the trial, starting with the highest selected dose group to be compared with the placebo at the full level ,. Left truncation, i.e., dropping doses in a sequence starting with the lowest dose, does not inflate the type I error rate. It is shown that right truncation does not inflate the type I error if efficacy and toxicity are positively related and dose selection is based on monotone functions of the safety data. A positive relation is given e.g. in the case where the efficacy and toxicity data are normally distributed with a positive pairwise correlation. A positive relation also applies if the probability for an adverse event is increasing with a normally distributed efficacy outcome. The properties of such truncation procedures are investigated by simulations. There is a conflict between achieving a small number of unsafely treated patients and a high power to detect safe and efficient doses. We also investigated a procedure to increase power where a reallocation of the sample size to the truncated treatments and the control remaining at the following stages is performed. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Testing Hardy-Weinberg Equilibrium using Family Data from Complex SurveysANNALS OF HUMAN GENETICS, Issue 4 2009Dewei She Summary Genetic data collected during the second phase of the Third National Health and Nutrition Examination Survey (NHANES III) enable us to investigate the association of a wide variety of health factors with regard to genetic variation. The classic question when looking into the genetic variations in a population is whether the population is in the state of Hardy-Weinberg Equilibrium (HWE). Our objective was to develop test procedures using family data from complex surveys such as NHANES III. We developed six Pearson ,2 based tests for a diallelic locus of autosomal genes. The finite sample properties of the proposed test procedures were evaluated via Monte Carlo simulation studies and the Rao-Scott first order corrected test was recommended. Test procedures were applied to three loci from NHANES III genetic databases, i.e., ADRB2, TGFB1, and VDR. HWE was shown to hold at 0.05 level for all three loci when only families with genotypic information available for two parents and for one or more children were used in the analysis. [source] Metabolism of fluoranthene in different plant cell cultures and intact plantsENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 5 2000Marit Kolb Abstract The metabolism of fluoranthene was investigated in 11 cell cultures of different plant species using a [14C]-labeled standard. Most species metabolized less than 5% of fluoranthene to soluble metabolites and formed less than 5% nonextractable residues during the standardized 48-h test procedure. Higher metabolic rates were observed in lettuce (Lactuca sativa, 6%), wheat (Tricitum aestivum, 9%), and tomato (Lycopersicon esculentum, 15%). A special high metabolic rate of nearly 50% was determined for the rose species Paul's Scarlet. Chromatographic analysis of metabolites extracted from aseptically grown tomato plants proved that the metabolites detected in the cell cultures were also formed in the intact plants. Metabolites produced in tomato and rose cells from [14C]-fluoranthene were conjugated with glucose, glucuronic acid, and other cell components. After acid hydrolyses, the main metabolite of both species was 1-hydroxyfluoranthene as identified by gas chromatography,mass spectrometry and high-performance liquid chromatography with diode array detection. The second metabolite formed by both species was 8-hydroxy-fluoranthene. A third metabolite in tomatoes was 3-hydroxyfluoranthene. [source] Influences of the Process Chain on the Fatigue Behavior of Samples with Tension Screw Geometry,ADVANCED ENGINEERING MATERIALS, Issue 4 2010Marcus Klein To analyze the influence of the material batch, the structure of the manufacturing process chain, and the process parameters, four different material batches of the quenched and tempered steel SAE 4140 were used to manufacture samples with tension screw geometry. Five different, manufacturing process chains, consisting of the process steps heat treatment, turning, and grinding, were applied. After selected process steps, light and SEM micrographs as well as fatigue experiments were performed. The process itself as well as the process parameters influences the properties of the surface layers and the fatigue behavior in a characteristic manner. For example the variation of the feed rate and cutting speed in the hard-turning process leads to significantly different mechanical properties of the surface layers and residual stress states, which could be correlated with the fatigue behavior. The cyclic deformation behavior of the investigated components can be benchmarked equivalently with stress,strain hysteresis as well as high precision temperature and electrical resistance measurements. The temperature and electrical resistance measurements are suitable for component applications and provide an enormous advantage of information about the fatigue behavior. The temperature changes of the failed areas of the samples with tension screw geometry were significantly higher, a reliable identification of endangered areas is thereby possible. A new test procedure, developed at the Institute of Materials Science and Engineering of the University of Kaiserslautern, with inserted load-free-states during constant amplitude loading, provides the opportunity to detect proceeding fatigue damage in components during inspections. [source] Generalization of robustness test procedure for error estimators.INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 4 2005Part I: formulation for patches near kinked boundaries Abstract In this part of paper we shall extend the formulation proposed by Babu,ka and co-workers for robustness patch test, for quality assessment of error estimators, to more general cases of patch locations especially in three-dimensional problems. This is performed first by finding an asymptotic finite element solution at interior parts of a problem with assumed smooth exact solution and then adding a correction part to obtain the solution near a kinked boundary irrespective of other boundary conditions at far ends of the domain. It has been shown that the solution corresponding to the correction part may be obtained in a spectral form by assuming a suitable proportionality relation between the nodal values of a mesh with repeatable pattern of macro-patches. Having found the asymptotic finite element solution, the performance of error estimators may be examined. Although in this paper we focus on the asymptotic behaviour of error estimators, the method described in this part may be used to obtain finite element solution for two/three-dimensional unbounded heat/elasticity problems with homogeneous differential equations. Some numerical results are presented to show the validity and performance of the proposed method. Copyright © 2005 John Wiley & Sons, Ltd. [source] Generalization of robustness test procedure for error estimators.INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 4 2005Part II: test results for error estimators using SPR Abstract In this part of the paper we shall use the formulation given in the first part to assess the quality of recovery-based error estimators using two recovery methods, i.e. superconvergent patch recovery (SPR) and recovery by equilibrium in patches (REP). The recovery methods have been shown to be asymptotically robust and superconvergent when applied to two-dimensional problems. In this study we shall examine the behaviour of the recovery methods on several three-dimensional mesh patterns for patches located either inside or at boundaries. This is performed by first finding an asymptotic finite element solution, irrespective of boundary conditions at far ends of the domain, and then applying the recovery methods. The test procedure near kinked boundaries is explained in a step-by-step manner. The results are given in a series of tables and figures for various cases of three-dimensional mesh patterns. It has been experienced that the full superconvergent property is generally lost due to presence of boundary layer solution and the definition of the recoveries near boundaries though the results of the robustness test is still within an acceptable range. Copyright © 2005 John Wiley & Sons, Ltd. [source] A quick, practical test procedure to evaluate the performance of instruments used for in vitro UV protection measurementsINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 6 2002E. Klette Synopsis The in vitro determination of the UV protection of sunscreens is usually performed by means of transmission measurements with special photometers. Many different instruments are used. Besides numerous commercially available instruments, which are equipped by the manufacturer for the specific measurement, other modular instruments are used. We present here a quick and practical method to evaluate the performance of these instruments with respect to their measuring ranges and to compare the uniformity and reliability of the results obtained with these instruments. Résumé La détermination in vitro de la protection anti-UV de produits solaires est généralement réalisée par la mesure de la transmission à l'aide de photomètres spéciaux. De nombreux appareils peuvent être utilisés à cette fin. A côté des instruments disponibles dans le commerce et spécialement équipés par les fabricants, d'autres appareils modulaires peuvent être employés. Nous présentons ici une méthode rapide et pratique pour évaluer les performances de ces appareils en respectant leurs gammes de mesure et pour comparer la crédibilité et l'uniformité des résultats obtenus. [source] A test procedure to characterise the heating performance of domestic microwave ovensINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 1 2008Mark Jeffery Swain Summary A test procedure has been developed and used to characterise the performance of domestic microwave ovens in relation to the heating of chilled ready meals. The procedure uses reproducible test loads, which simulate the heating and weight loss characteristics of a chilled ready meal under consumer use. The temperature distribution after heating from 5 °C to a defined minimum temperature of 70 °C is measured in the food simulant using a purpose designed multipoint thermocouple ,hedgehog' probe. The temperature, weight loss and heating time data from the test are entered into a spreadsheet analysis program, which provides a simple oven performance ,score' and/or comprehensive heating performance data. [source] Quadratic Differential Demand Systems and the Retail Demand for Pork in Great BritainJOURNAL OF AGRICULTURAL ECONOMICS, Issue 3 2003Panos Fousekis The primary objective of this paper is to derive a general synthetic quadratic (rank 3) differential demand system which nests within it a range of testable differential demand models including the quadratic AIDS, CBS, Rotterdam and NBR systems. A model selection test procedure is also outlined. These differential systems are then applied and tested to analyse the monthly retail demand for cuts of pork in Great Britain over the period 1989,2000. The empirical results suggest that a quadratic differential AIDS model is most appropriate for the pork demand system studied, but that the need for inclusion of quadratic income/expenditure terms is not universal for every cut within the demand system. Quadratic expenditure effects were appropriate for pork chops and leg roasts, but log linear expenditure effects were adequate for bellies, shoulders and loin roasts. Roasting cuts were expenditure and own price elastic, with pork loins, chops and bellies all expenditure and own price inelastic. [source] Clinical outcomes following treatment of human intrabony defects with GTR/bone replacement material or access flap aloneJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 9 2004A multicenter randomized controlled clinical trial Abstract Aim: This prospective multicenter randomized controlled clinical trial was designed to compare the clinical outcomes of papilla preservation flap surgery with or without the application of a guided tissue regeneration (GTR)/bone replacement material. Materials and Methods: One hundred and twenty-four patients with advanced chronic periodontitis were recruited in 10 centers in seven countries. All patients had at least one intrabony defect of 3 mm. The surgical procedures included access for root instrumentation using either the simplified or the modified papilla preservation flap in order to obtain optimal tissue adaptation and primary closure. After debridement, the regenerative material was applied in the test subjects, and omitted in the controls. At baseline and 1 year following the interventions, clinical attachment levels (CALs), probing pocket depths (PPDs), recession, full-mouth plaque scores and full-mouth bleeding scores (FMBS) were assessed. Results: One year after treatment, the test defects gained 3.3±1.7 mm of CAL, while the control defects yielded a significantly lower CAL gain of 2.5±1.5 mm. Pocket reduction was also significantly higher in the test group (3.7±1.8 mm) when compared with the controls (3.2±1.5 mm). A multivariate analysis indicated that the treatment, the clinical centers, baseline PPD and baseline FMBS significantly influenced CAL gains. Odds ratios (ORs) of achieving above-median CAL gains were significantly improved by the test procedure (OR=2.6, 95% CI 1.2,5.4) and by starting with deeper PPD (OR=1.7, 1.3,2.2) but were decreased by receiving treatment at the worst-performing clinical center (OR=0.9, 0.76,0.99). Conclusions: The results of this trial indicated that regenerative periodontal surgery with a GTR/bone replacement material offers an additional benefit in terms of CAL gains, PPD reductions and predictability of outcomes with respect to papilla preservation flaps alone. [source] Determining the causality between retail price and consumer demand in a linear function when demand-shift variables are missing but wholesale prices are availableAGRIBUSINESS : AN INTERNATIONAL JOURNAL, Issue 2 2005W. Erno Kuiper A test procedure is proposed to test for the simultaneous nature of the relationship between price and quantity with respect to consumer demand of fresh products at the level of an individual retail chain. It is argued in the literature that, on the sector level, inverse demand systems in which quantities are exogenous and prices are the dependent variables are better able to describe consumer demand behavior in case of perishable products whose quantities may be treated as fully price inelastic in the short run. Nevertheless, applying our test procedure to six fresh vegetable products sold by a Dutch supermarket chain reveals that consumer demand for fresh products is better described by a simultaneous price,quantity relationship. [EconLit citations: C320, D420, Q110.] © 2005 Wiley Periodicals, Inc. Agribusiness 21: 167,176, 2005. [source] Tensile bond strengths of four different dentin adhesives on irradiated and non-irradiated human dentin in vitroJOURNAL OF ORAL REHABILITATION, Issue 9 2001C. R. Gernhardt This study evaluated the influence of irradiation on dentin bond strength. Sixty irradiated and 60 non-irradiated human third molars were used. The irradiation dose of 60 Gy was fractionally applied over 6 weeks (2 Gy day,1, 5 days week,1). All teeth were prepared in a special manner allowing the simulation of intra-pulpal pressure and dentin perfusion. Dentin specimens with a thickness of 2·0 mm were obtained under standardized conditions. The specimens were randomly assigned to four experimental groups. Tensile bond strength of four different dentin bonding agents (ScotchbondÔ 1, Solobond Plus®, Prime&BondÔ 2·1 and Syntac®) was evaluated using an Instron Universal testing machine. Pairwise comparison did not show any significant differences between the irradiated and non-irradiated groups. The influence of the different dentin adhesives was significant (P=0·0001; ANOVA). Compared with Solobond Plus® and Prime&BondÔ 2·1, the use of ScotchbondÔ 1 resulted in a significantly higher tensile bond strength in non-irradiated specimen (P< 0·05; closed test procedure based on Kruskal,Wallis test). Within the limitations of an in vitro study, it can be concluded that adhesive restoration procedures can be successfully used in patients irradiated for cancer of the head and neck. [source] Hydrodynamic investigation of USP dissolution test apparatus IIJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 9 2007Ge Bai Abstract The USP Apparatus II is the device commonly used to conduct dissolution testing in the pharmaceutical industry. Despite its widespread use, dissolution testing remains susceptible to significant error and test failures, and limited information is available on the hydrodynamics of this apparatus. In this work, laser-Doppler velocimetry (LDV) and computational fluid dynamics (CFD) were used, respectively, to experimentally map and computationally predict the velocity distribution inside a standard USP Apparatus II under the typical operating conditions mandated by the dissolution test procedure. The flow in the apparatus is strongly dominated by the tangential component of the velocity. Secondary flows consist of an upper and lower recirculation loop in the vertical plane, above and below the impeller, respectively. A low recirculation zone was observed in the lower part of the hemispherical vessel bottom where the tablet dissolution process takes place. The radial and axial velocities in the region just below the impeller were found to be very small. This is the most critical region of the apparatus since the dissolving tablet will likely be at this location during the dissolution test. The velocities in this region change significantly over short distances along the vessel bottom. This implies that small variations in the location of the tablet on the vessel bottom caused by the randomness of the tablet descent through the liquid are likely to result in significantly different velocities and velocity gradients near the tablet. This is likely to introduce variability in the test. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 96: 2327,2349, 2007 [source] ARTICULATED CONCRETE BLOCK STABILITY TESTING,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 1 2001Steven R. Abt ABSTRACT: An articulated concrete block revetment system was developed by the U.S. Army Corps of Engineers to test and evaluate the practicability of the protocols for overtopping and channelized flow conditions. Test facilities were constructed, prototype articulated concrete blocks were fabricated and installed into the facilities, and the blocks were tested using the established protocols. The test results indicated that both the overtopping and channel flow tests yielded similar results: the blocks reached a point of instability at approximately the same velocity and shear stresses. The similar test results indicate that only one protocol is required to evaluate an articulated concrete block system. It was demonstrated that both protocols can be effectively conducted. It is recommended that the overtopping test be adapted as a standard test procedure because of its reduced construction costs and its efficiency compared to the channelized test. [source] Modifications to improve the accuracy of a four-ball test apparatusLUBRICATION SCIENCE, Issue 1 2000P. I. Lacey Abstract The four-ball wear test machine is one of the most widely used tribological tools in both research and industry. In general, the test geometry is self-aligning and minimises the opportunity for random variation. Nonetheless, accurate control of the test parameters remains vital to repeatability and reproducibility. The present paper details a number of modifications to a commercially available test apparatus that have been found to improve accuracy. The applied load on some apparatus was found to vary from the correct value, probably due to frictional drag in the loading system. A feedback control loop was designed and fitted to the applied load mechanism, which resulted in significantly improved accuracy. Finally, the apparatus was fully automated, with complete computer control of all test parameters. Under this, following cleaning and assembly of the test specimens, the required test procedure could be selected from a menu of standard methods, and the computer program then adjusted the test parameters according to the method selected, greatly reducing the possibility of operator error. [source] A feasibility study of daytime fog and low stratus detection with TERRA/AQUA-MODIS over landMETEOROLOGICAL APPLICATIONS, Issue 2 2006Jörg Bendix Abstract A scheme for the detection of fog and low stratus over land during daytime based on data of the MODIS (Moderate Resolution Imaging Spectroradiometer) instrument is presented. The method is based on an initial threshold test procedure in the MODIS solar bands 1,7 (0.62,2.155µm). Fog and low stratus detection generally relies on the definition of minimum and maximum fog and low stratus properties, which are converted to spectral thresholds by means of radiative transfer calculations (RTC). Extended sensitivity studies reveal that thresholds mainly depend on the solar zenith angle and, hence, illumination-dependent threshold functions are developed. Areas covered by snow, ice and mid-/high-level clouds as well as bright/hazy land surfaces are omitted from the initial classification result by means of a subsequent cloud-top height test based on MODIS IR band 31 (at 12 µm) and a NIR/VIS ratio test. The validation of the final fog and low stratus mask generally shows a satisfactory performance of the scheme. Validation problems occur due to the late overpass time of the TERRA platform and the time lag between SYNOP and satellite observations. Apparent misclassifications are mainly found at the edge of the fog layers, probably due to over- or underestimation of fog and low stratus cover in the transition zone from fog to haze. Copyright © 2006 Royal Meteorological Society. [source] Equivalence of hydroxyethyl starch HES 130/0.ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 9 2003HES 200/0. Background:, Hydroxyethyl starch solutions (HES) are increasingly used for the compensation of surgical blood loss. The objective of this clinical trial was to compare a novel 6% HES 130/0.4 solution with a favourable pharmacological profile and a standard 6% HES 200/0.5 solution for maintenance of haemodynamic stability in major gynaecological surgery. Methods:, Sixty female patients aged 18,80 years undergoing major gynaecological surgery with indication for perioperative colloidal volume replacement were enrolled in this prospective, randomized double-blinded clinical study. The administration of study medication was dependent on individual requirements to maintain haemodynamic stability. The amount of study medication required from induction of anaesthesia until 6 h postoperatively served as the primary investigative parameter. Results:, The two one-sided test procedure by Westlake demonstrated equivalence of mean infused volumes between HES 130/0.4 and HES 200/0.5 during the study period (1224 ± 544 ml and 1389 ± 610 ml, respectively, P < 0.05). Perioperatively, haemodynamics did not differ significantly between treatment groups. While none of the mean values of coagulation parameters shifted outside the normal range, the degree of haemodilution revealed reduced haematocrit values in HES 200/0.5 treated patients at 6 h postoperatively (P < 0.05). Moreover, prothrombin time (PT) was higher and consequently international normalized ratio (INR) was lower at the same time point for patients who received HES 130/0.4 (P < 0.05). Conclusion:, This clinical trial demonstrated therapeutic equivalence of this novel low-substituted HES 130/0.4 solution and a standard HES 200/0.5 solution for perioperative volume replacement. Moreover, both HES preparations were equally well-tolerated and safe. [source] Impact of modified acidic soft drinks on enamel erosionORAL DISEASES, Issue 1 2005T Attin Objective:, To evaluate the enamel erosive potential of modified acidic soft drinks under controlled conditions in an artificial mouth. Materials and methods:, From each of 144 bovine incisors one enamel sample was prepared. Labial surfaces of the samples were ground flat, polished and covered with adhesive tape, leaving an exposed area. The samples were distributed among four (A,D) groups for treatment with A: Coca-Cola, B: Sprite; C: Sprite light, D: orange juice. Either 1.0 mmol l,1 calcium (Ca) or a combination (comb.) of 0.5 mmol l,1 calcium plus 0.5 mmol l,1 phosphate plus 0.031 mmol l,1 fluoride was added to the beverages. Samples of each group were subdivided into three subgroups (-original; -Ca and -comb.) for treatment with original and modified drinks. De- and remineralization cycles were based on a standard protocol described earlier. Surface loss of the specimens was determined using profilometry after test procedure. Results:, In all subgroups, loss of enamel was observed. The enamel loss recorded for the samples rinsed with original Sprite and original orange juice was significantly higher compared with all other solutions (P = 0.001). Lowest enamel loss was recorded for the original Coca-Cola group (P = 0.001). With the exception of Coca-Cola, demineralization with the modified beverages led to significantly lower losses compared with the respective original solutions. Conclusion:, Modification of the test soft drinks with low concentrations of calcium or a combination of calcium, phosphate and fluoride may exert a significant protective potential with respect to dental erosion. [source] Innovational Outlier Unit Root Tests With an Endogenously Determined Break in LevelOXFORD BULLETIN OF ECONOMICS & STATISTICS, Issue 5 2001David I. Harvey We show that a standard unit root test that permits an endogenously determined break in level can generate spurious rejections in practically interesting sample sizes when a large break occurs under the null hypothesis. This problem, which occurs for breaks of the innovational outlier type, can be corrected through a simple modification of the test procedure. [source] Phototoxicity of exogenous protoporphyrin IX and ,-aminolevulinic acid in the photo hen's egg testPHOTODERMATOLOGY, PHOTOIMMUNOLOGY & PHOTOMEDICINE, Issue 5 2004Norbert J. Neumann Background: Oxygen, appropriate light sources, and special photosensitizers are necessary to induce photochemical damage in tumor cells via photodynamic therapy (PDT) ,-aminolevulinic acid (ALA) is increasingly used in PDT, because topical or systemic administration of ALA induces accumulation of endogenous porphyrins preferentially in neoplastic tissues. Subsequent radiation with light of approximately 630 nm leads to selective damage of tumor cells. PDT should optimally leave peritumoral tissues unaffected, but only few data are reported on the effects and the time course of ALA-induced porphyrins in tumor-free tissues. Methods: Therefore, we studied the phototoxic effects of protoporphyrin IX (PP) and ALA-induced porphyrins in a recently established photototoxic model based on tumor-free tissue, the photo hen's egg test (PHET). Results: Employing this test procedure, PP provoked strong phototoxic reactions when irradiated with Ultraviolet A immediately and up to 30 h after substance application. In contrast, ALA induced a significant phototoxic effect only if irradiated 24 h after application. Conclusion: Thus, we observed a delayed phototoxic effect of ALA in tumor-free tissue of the yolk sac (YS) blood vessel system. This delayed phototoxic response 24 h after ALA application is probably caused by endogenously synthesized porphyrins. In contrast, epithelial tumors show a maximum porphyrin accumulation 4,8 h after ALA application whereas in healthy human skin porphyrin synthesis is less intensive but prolonged with maximum levels 24,48 h after ALA application. Thus, ALA induced virtually the same delayed phototoxic effect in the tumor-free YS blood vessel tissue as in healthy human skin. These results show that the PHET is a useful model for the predictive preclinical risk assessment of exogenous or endogenous photosensitizers. [source] Evaluation of a soil-amendment process demonstration for reducing the bioavailability of leadREMEDIATION, Issue 4 2002Edwin F. Barth The U.S. Environmental Protection Agency (EPA) evaluated an in-situ application of a soil-amendment process at a residential site that was contaminated with lead. The goal of the evaluation was to determine if the soil-amendment process resulted in lower concentrations of bioavailable lead in the contaminated soils. The relative bioavailability of lead (bioaccessible lead) was measured by an in vitro test procedure that uses a highly acidic extraction procedure to simulate human digestive processes. The soil-amendment demonstration showed that the 11.2 percent mean reduction in bioavailable lead concentration between untreated and treated soils was not statistically different. © 2002 Wiley Periodicals, Inc. [source] The effect of postevent information on adults' eyewitness reportsAPPLIED COGNITIVE PSYCHOLOGY, Issue 3 2001Rachel Sutherland The present experiment examined the conditions under which adults' reports of an event are influenced by information encountered after the event occurred. Adults were exposed to neutral, leading, and misleading postevent information about a target event 24 hours after that event. Twenty-four hours after exposure to postevent information, participants were first asked a general, open-ended question (free recall test procedure) and were then asked a series of specific questions. Some participants were asked to select their response from two possible alternatives (recognition test procedure) and some participants were required to generate their own answers to the same questions (directed recall test procedure). The nature of the original information, the nature of the postevent information, and the specificity of the questioning procedure influenced the number of correct responses and the number of misleading errors that participants made. These findings have important implications for interviewing adult witnesses. Copyright © 2001 John Wiley & Sons, Ltd. [source] On testing of parameters in modulated power law processAPPLIED STOCHASTIC MODELS IN BUSINESS AND INDUSTRY, Issue 4 2001K. Muralidharan Abstract The modulated power law process (MPLP) is often used to model failure data from repairable system, when both renewal type behaviour and time trends are present. The MPLP allows for the failure rate of a system to be affected by the failure and repair. Since the MLEs of the estimates do not have closed form expressions, they have to be approximated, and hence deriving a test procedure will be difficult. Black and Rigdon (1996) have proposed asymptotic MLEs and asymptotic likelihood ratio tests for the parameters which also do not have closed form expressions and hence are not easy for application. In this paper, we derive a closed form expression for the test statistics which is simple and easy to apply for testing (i) H0: ,=1 versus H1: ,,1 when , is known and (ii) H0: (,=1 and ,=1) versus H1: (,,1 or ,,1). The simulation study for percentiles and powers are given. We also compare the performance of the test with that of Black and Rigdon's (1996) test. Some numerical examples are also provided to illustrate the testing procedures. Copyright © 2001 John Wiley & Sons, Ltd. [source] Heart Transplantation at the Ottawa Heart Institute: Comparison with Canadian and International ResultsARTIFICIAL ORGANS, Issue 2 2004Ross A. Davies Abstract:, Heart transplantation has been carried out in 340 patients in Ottawa, including seventy-one who required mechanical circulatory support as a bridge to transplant. Survival in Ottawa was compared with other Canadian centers based on data from the Canadian Organ Replacement Register up to the year 2000 and with the International Society of Heart and Lung Transplantation (ISHLT) registry 2001. For survival analysis, the number of adult patients at risk at year 0 was 303 (87 transplanted from 1985 to 1990, 105 from 1990 to 1994, and 111 from 1995 to 2000). The Statistical Analysis System (SAS) life test procedure was used. Survival was not adjusted for comorbidities or heart failure class. For the year of transplant 1985,1989, one-, five-, and ten-year patient survival in Ottawa was 83%, 70%, and 60%, respectively, compared to 82%, 71%, and 54%, respectively, for Canada (Wilcoxon test, P = 0.71), and compared to one- and five-year survival for ISHLT from 1980 to 1987 at 76% and 60%, respectively. For 1990,1994, one-, five-, and ten-year patient survival in Ottawa was 88%, 81%, and 74%, respectively, compared to 80%, 71%, and 61%, respectively, for Canada (P = 0.05), and compared to one- and five-year survival for ISHLT from 1998 to 1992 at 80% and 68%, respectively. For 1995,2000, one- and five-year patient survival in Ottawa was 90% and 82%, respectively, compared to 85% and 76%, respectively, for Canada (P = 0.09), and compared to one- and five-year survival for ISHLT from 1993 to 1996 at 82% and 68%, respectively. Survival after heart transplantation in Ottawa compares ,favorably ,with ,Canadian ,and ,international data. [source] Plotting Robust Root Locus For Polynomial Families Of Multilinear Parameter Dependence Based On Zero Inclusion/Exclusion TestsASIAN JOURNAL OF CONTROL, Issue 2 2003Chyi Hwang ABSTRACT The Mapping Theorem by Zadeh and Desoer [17] is a sufficient condition for the zero exclusion of the image or value set of an m -dimensional box B under a multilinear mapping f: Rm , C, where R and C denote the real line and the complex plane, respectively. In this paper, we present a sufficient condition for the zero inclusion of the value set f(B). On the basis of these two conditions and the iterative subdivision of the box B, we propose a numerical procedure for testing whether or not the value set f(B) includes the origin. The procedure is easy to implement and is more efficient than that based on constructing the value set f(B) explicitly. As an application, the proposed zero inclusion test procedure is used along with a homotopy continuation algorithm to trace out the boundary curves of the robust root loci of polynomial families with multilinear parametric uncertainties. [source] ARE CHINESE STOCK MARKETS INCREASING INTEGRATION WITH OTHER MARKETS IN THE GREATER CHINA REGION AND OTHER MAJOR MARKETS?AUSTRALIAN ECONOMIC PAPERS, Issue 3 2007GARY GANG TIAN This paper investigates the cointegrating and long-term causal relationships between the Shanghai A and B-share market, and between these two markets and the Hong Kong, the Taiwanese, the Japanese and the US market of two sub periods between July 1993 and March 2007. On the basis of a new Granger non-causality test procedure developed by Toda-Yamamoto (1995) and Johansen's (1988) cointegration test, my results suggest that a long-term equilibrium relationship measured by cointegration has been merged between the Chinese A-share market and the other markets in greater China region as well as the US market during the post-crisis period which covers the period since Chinese A-share market was opened to the Qualified Foreign Institutional Investors (QFII) in 2002. I also found that the Shanghai A-share market uni-directionally Granger-causes the other regional markets after the Asian financial crisis, while the A-share market and Hong Kong H-share market have had a significant feedback relationship since then. However, I found no evidence there has been cointegrating relationship between Shanghai B-share market and any other market ever since the B-share market was opened to the local retail investors in 2001. [source] Piecewise analysis and modeling of circuit pack temperature cycling dataBELL LABS TECHNICAL JOURNAL, Issue 3 2006Toby Joyce Temperature cycling environmental stress testing (EST) of circuit packs is a standard test procedure for the precipitation of latent defects in order to minimize early product lifecycle customer returns. EST is an expensive, energy-intensive bottleneck in the manufacturing process, one that is based on empiricisms that may be out of date. This presents great opportunity for optimization and test cost reduction. This paper describes the characterization of temperature cycling through analysis and modeling of process data in order to optimize the test parameters,ramp rate, temperature extremes, dwell times, and number of cycles. Failure data from circuit packs tested at a Lucent facility is analyzed using a regression technique and graphical inspection. The dwell and ramp periods of the test are considered in a piecewise manner. A cost model is applied based on distributions fitted to the failure data. The analysis yields a methodology for the dynamic, value-based optimization of temperature cycling EST. © 2006 Lucent Technologies Inc. [source] Adaptive patient enrichment designs in therapeutic trialsBIOMETRICAL JOURNAL, Issue 2 2009Sue-Jane Wang Abstract The utility of clinical trial designs with adaptive patient enrichment is investigated in an adequate and well-controlled trial setting. The overall treatment effect is the weighted average of the treatment effects in the mutually exclusive subsets of the originally intended entire study population. The adaptive enrichment approaches permit assessment of treatment effect that may be applicable to specific nested patient (sub)sets due to heterogeneous patient characteristics and/or differential response to treatment, e.g. a responsive patient subset versus a lack of beneficial patient subset, in all patient (sub)sets studied. The adaptive enrichment approaches considered include three adaptive design scenarios: (i) total sample size fixed and with futility stopping, (ii) sample size adaptation and futility stopping, and (iii) sample size adaptation without futility stopping. We show that regardless of whether the treatment effect eventually assessed is applicable to the originally studied patient population or only to the nested patient subsets; it is possible to devise an adaptive enrichment approach that statistically outperforms one-size-fits-all fixed design approach and the fixed design with a pre-specified multiple test procedure. We emphasize the need of additional studies to replicate the finding of a treatment effect in an enriched patient subset. The replication studies are likely to need fewer number of patients because of an identified treatment effect size that is larger than the diluted overall effect size. The adaptive designs, when applicable, are along the line of efficiency consideration in a drug development program. [source] An Adaptive Hierarchical Test Procedure for Selecting Safe and Efficient TreatmentsBIOMETRICAL JOURNAL, Issue 4 2006Franz König Abstract We consider the situation where during a multiple treatment (dose) control comparison high doses are truncated because of lack of safety and low doses are truncated because of lack of efficacy, e.g., by decisions of a data safety monitoring committee in multiple interim looks. We investigate the properties of a hierarchical test procedure for the efficacy outcome in the set of doses carried on until the end of the trial, starting with the highest selected dose group to be compared with the placebo at the full level ,. Left truncation, i.e., dropping doses in a sequence starting with the lowest dose, does not inflate the type I error rate. It is shown that right truncation does not inflate the type I error if efficacy and toxicity are positively related and dose selection is based on monotone functions of the safety data. A positive relation is given e.g. in the case where the efficacy and toxicity data are normally distributed with a positive pairwise correlation. A positive relation also applies if the probability for an adverse event is increasing with a normally distributed efficacy outcome. The properties of such truncation procedures are investigated by simulations. There is a conflict between achieving a small number of unsafely treated patients and a high power to detect safe and efficient doses. We also investigated a procedure to increase power where a reallocation of the sample size to the truncated treatments and the control remaining at the following stages is performed. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Combining Treatment Selection and Definitive TestingBIOMETRICAL JOURNAL, Issue 4 2006Michael A. Proschan Abstract This is a discussion of the following two papers appearing in this special issue on adaptive designs: ,An adaptive hierarchical test procedure for selecting safe and efficient treatments' by Franz König, Peter Bauer and Werner Brannath, and ,An adaptive two-stage design with treatment selection using the conditional error function approach' by Jixian Wang. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||||||||||||||||||||||||||