Home About us Contact
|
Home About us Contact | ||
|
|
||
Testing Strategies (testing + strategy)
Selected AbstractsTesting strategies looking forwardISBT SCIENCE SERIES: THE INTERNATIONAL JOURNAL OF INTRACELLULAR TRANSPORT, Issue n1 2010C. Bianco First page of article [source] Comparison of the performance of rapid HIV tests using samples collected for surveillance in Mozambique,JOURNAL OF MEDICAL VIROLOGY, Issue 12 2009Josefa Melo Abstract Mozambique had low HIV prevalence until the mid-1990s, but recent data indicate increasing rates. There is little information on HIV-2. Therefore, HIV seroprevalence was assessed among pregnant women and field-ready HIV diagnostic strategies were evaluated. A total of 6,930 samples collected by three health centers from 2002 to 2005 were tested on site by nurses with two simple/rapid tests, Determine HIV-1/2 (Abbott Laboratories; screening) and Uni-Gold HIV (Trinity Biotech; confirmation), which is the national HIV testing strategy. The prevalence of HIV was 14.0% (2002), 17.8% (2003), 16.5% (2004), and 20.2% (2005). A subset of 888 samples collected 2003 was sent to the Central Microbiology Laboratory, Maputo for evaluation of tests and testing strategies. The assays included for comparison were Capillus HIV-1/HIV-2 (Trinity Biotech), DoubleCheckGold HIV-1&2 (Orgenics) and Enzygnost Anti-HIV-1/2 Plus (Behringwerke, reference ELISA). Confirmation of reactive samples was done by Uni-Gold HIV and ImmunoComb II HIV-1&2 BiSpot (for HIV type differentiation). The Capillus HIV-1/ HIV-2,+,ImmunoComb II HIV-1&2 BiSpot combination was the gold standard. The sensitivity of the rapid/simple screening assays (Determine HIV-1/2, DoubleCheckGold HIV-1&2) was 100% (N,=,160) and their (initial) specificities were 99.6% and 99.7%, respectively. Repeated testing and combinations of assays increased the specificity. Four suspected cases of recent seroconversion were found. Together with the increasing prevalence rates, this may indicate that Mozambique is a high-incidence area, although further studies are needed to confirm this. Testing strategies for on-site screening and confirmation based on the combination of Determine HIV-1/2, Uni-Gold HIV and DoubleCheckGold HIV-1&2 are well suited for local field use. J. Med. Virol. 81:1991,1998, 2009. © 2009 Wiley-Liss, Inc. [source] A new multimarker test for family-based association studiesGENETIC EPIDEMIOLOGY, Issue 1 2007Cyril S. Rakovski Abstract We propose a new multimarker test for family-based studies in candidate genes. We use simulations under different genetic models to assess the performance of competing testing strategies, characterized in this study as combinations of the following important factors: genes, statistical tests, tag single nucleotide polymorphisms (SNP) methods, number of tag SNPs and family designs. An ANOVA model is employed to provide descriptive summaries of the effects on power of the above-mentioned factors. We find that tag SNP methods, gene characteristics and family designs have minimal impact on the best testing strategy. The familywise error rate (FWER) controlling multiple comparison procedure and the new multimarker test offer the highest power followed by the asymptotic global haplotype test. Both the FWER and the multimarker test are invariant to family designs and gain power as we increase the number of tag SNPs. However, the performance of the global haplotype test is slightly degraded when analyzing larger numbers of tag SNPs. Within the framework of our study, the best strategy for family-based studies in candidate genes that emerged from our analysis is to use the FWER or the multimarker test and select 6,10 tag SNPs using any of the tag SNP methods considered. We confirm the conclusions of our study with an application to Alzheimer's disease data. Genet. Epidemiol. © 2006 Wiley-Liss, Inc. [source] HPV triage testing or repeat Pap smear for the management of atypical squamous cells (ASCUS) on Pap smear: is there evidence of process utility?HEALTH ECONOMICS, Issue 5 2008Kirsten Howard Abstract A two-stage standard gamble was used to evaluate women's preferences for alternative managements of atypical squamous cells of undermined significance (ASCUS) on Pap smear (repeat Pap smear compared with immediate HPV test), and to test for the evidence of process utility. Women's utilities for the health state scenarios were clustered towards the upper end of the 0,1 scale with considerable variability in women's preferences. There was evidence of process utility, with immediate human papillomavirus (HPV) testing strategies having lower valuations than repeat Pap smear, where the clinical outcome was the same. Mean (95% CI) utilities for HPV testing (negative test) followed by resolution were 0.9967 (0.9957,0.9978) compared with repeat Pap smear followed by resolution: 0.9972 (0.9964,0.9980). Mean (95% CI) utilities for immediate HPV testing (positive test), followed by colposcopy, biopsy and treatment were 0.9354 (0.8544,1.0) compared with repeat Pap smear followed by colposcopy, biopsy and treatment: 0.9656 (0.9081,1.0). Our results add to the existing evidence that the impact of healthcare interventions on well-being is not limited to the effect of the intervention on the health outcomes expected from the intervention; process of care can have quality of life implications for the individual. A modelled application of trial-based data will allow characterisation of the true population costs, benefits, risks and harms of alternative triage strategies and subsequent policy implications thereof. Copyright © 2007 John Wiley & Sons, Ltd. [source] Good practice in plasma collection and fractionationISBT SCIENCE SERIES: THE INTERNATIONAL JOURNAL OF INTRACELLULAR TRANSPORT, Issue n1 2010C. Schärer The control strategy to ensure safety of blood products includes a combination of measures focusing on ensuring the quality and safety of starting material by careful donor selection and testing strategies at different levels, together with validated manufacturing processes, including steps to inactivate or remove potential contaminating agents. Using an approach based on good manufacturing practice (GMP) provides a manufacturing model that allows for a documented system of incorporating quality throughout the entire manufacturing process and describes the activities and controls needed to consistently produce products that comply with specifications and are safe for use. There are no doubts that the aim of providing safe and high-quality product to the patients should be the same for all products derived from human blood, independent of its use either as a blood component for direct transfusion or as industrially manufactured product. It would be difficult to justify whether for blood components the good practice standards and for plasma derivatives the GMP standards for manufacturing would not ensure equivalent levels of quality and safety. To ensure a high level of quality and safety of blood components and plasma derivatives, the implementation of double standards in blood establishments and fractionation industry would not be effective and should be avoided. Harmonized standards and good practices for collection and fractionation, based on the principles of GMP, should be envisaged in the whole chain of manufacturing blood components and plasma derivatives. Global initiatives to further promote the implementation of harmonized GMP for the collection in blood establishments and a stringent regulatory control are ongoing. This would further contribute to the global availability of plasma-derived medicinal products. [source] The adrenal cortex and steroidogenesis as cellular and molecular targets for toxicity: critical omissions from regulatory endocrine disrupter screening strategies for human health?JOURNAL OF APPLIED TOXICOLOGY, Issue 2 2003Philip W. Harvey Abstract Current testing strategies to assess the endocrine disrupting properties of chemicals have omitted examination of the adrenal gland and do not adequately cover the process of steroidogenesis. Steroidogenesis is critical for adrenocortical function as well as that of the testes and ovaries, and presents multiple molecular targets for toxicity, ranging from general effects on all steroidogenic tissues (e.g. via StAR protein or CYP11A1 cholesterol side-chain cleavage) through to speci,c targets affecting only adrenocortical function (e.g. CYP11,/18 and glucocorticoid synthesis). Numerous chemicals of environmental relevance are now being shown to affect adrenocortical function both in vivo in aquatic species and in vitro in human cell lines, and given the vital role of the adrenal gland to human health and development, there is a strong case for including dedicated assessment techniques in screening batteries for endocrine-disrupting chemicals, not least to assist in general data interpretation (e.g. whether adrenal hypertrophy is due to stress or to a more sinister adrenocortical insuf,ciency). Cell lines such as H295R (derived from a human adrenocortical adenocarcinoma) currently exist that will allow assessment of cortisol production and most of the major enzymes and functional proteins in the steroidogenic pathway (e.g. StAR; CYP11A1/scc; CYP11,/18; CYP17; CYP19; CYP21; 3, -hydroxysteroid dehydrogenase). Adequate assessment of adrenocortical function, as with any component of the integrated endocrine system, probably also will require the development of speci,c in vivo methodology to include effects on hypothalamo-pituitary function. Finally, although there is currently no direct evidence that environmental exposure to endocrine-disrupting (oestrogenic) chemicals has actually caused adverse human health effects, lessons have been learned on their potential from the diethylstilboestrol case. Similar evidence exists from aminoglutethimide and etomidate on the lethal impact of unpredicted chemically induced adrenal insuf,ciency in sensitive human subgroups, and it would seem prudent to incorporate relevant tests for adrenal function and steroidogenesis into current regulatory validation programmes. Published in 2003 by John Wiley & Sons, Ltd. [source] Comparison of the performance of rapid HIV tests using samples collected for surveillance in Mozambique,JOURNAL OF MEDICAL VIROLOGY, Issue 12 2009Josefa Melo Abstract Mozambique had low HIV prevalence until the mid-1990s, but recent data indicate increasing rates. There is little information on HIV-2. Therefore, HIV seroprevalence was assessed among pregnant women and field-ready HIV diagnostic strategies were evaluated. A total of 6,930 samples collected by three health centers from 2002 to 2005 were tested on site by nurses with two simple/rapid tests, Determine HIV-1/2 (Abbott Laboratories; screening) and Uni-Gold HIV (Trinity Biotech; confirmation), which is the national HIV testing strategy. The prevalence of HIV was 14.0% (2002), 17.8% (2003), 16.5% (2004), and 20.2% (2005). A subset of 888 samples collected 2003 was sent to the Central Microbiology Laboratory, Maputo for evaluation of tests and testing strategies. The assays included for comparison were Capillus HIV-1/HIV-2 (Trinity Biotech), DoubleCheckGold HIV-1&2 (Orgenics) and Enzygnost Anti-HIV-1/2 Plus (Behringwerke, reference ELISA). Confirmation of reactive samples was done by Uni-Gold HIV and ImmunoComb II HIV-1&2 BiSpot (for HIV type differentiation). The Capillus HIV-1/ HIV-2,+,ImmunoComb II HIV-1&2 BiSpot combination was the gold standard. The sensitivity of the rapid/simple screening assays (Determine HIV-1/2, DoubleCheckGold HIV-1&2) was 100% (N,=,160) and their (initial) specificities were 99.6% and 99.7%, respectively. Repeated testing and combinations of assays increased the specificity. Four suspected cases of recent seroconversion were found. Together with the increasing prevalence rates, this may indicate that Mozambique is a high-incidence area, although further studies are needed to confirm this. Testing strategies for on-site screening and confirmation based on the combination of Determine HIV-1/2, Uni-Gold HIV and DoubleCheckGold HIV-1&2 are well suited for local field use. J. Med. Virol. 81:1991,1998, 2009. © 2009 Wiley-Liss, Inc. [source] Testing and maintaining de-localized software systems in a multi-site environment using Web-based toolsJOURNAL OF SOFTWARE MAINTENANCE AND EVOLUTION: RESEARCH AND PRACTICE, Issue 3 2002Balaji .V Abstract Web-based approaches used during software maintenance for testing de-localized software in a multi-site environment are described. The supporting infrastructure uses the Internet for communications and project management practices for procedural direction. Processes involve specifying personnel roles and using a configuration management system for test schedules and the handling of test results. Different testing strategies are used during various stages of the maintenance lifecycle; each has benefits and weaknesses. Test results are automated using scripts, and a Web interface is provided to obtain better tracking. This achieves a operational effectiveness by using automation and regression testing mechanisms, and results in documented cost savings and software quality improvements. Copyright © 2002 John Wiley & Sons, Ltd. [source] Clinical trial: a randomized trial of early endoscopy, Helicobacter pylori testing and empirical therapy for the management of dyspepsia in primary careALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 1 2009A. E. DUGGAN Summary Background, Early endoscopy, Helicobacter pylori eradication and empirical acid suppression are commonly used dyspepsia management strategies in primary care but have not been directly compared in a single trial. Aim, To compare endoscopy, H. pylori test and refer, H. pylori test and treat and empirical acid suppression for dyspepsia in primary care. Methods, Patients presenting to their general practitioner with dyspepsia were randomized to endoscopy, H. pylori,test and treat', H. pylori test and endoscope positives, or empirical therapy with symptoms, patient satisfaction, healthcare costs and cost effectiveness at 12 months being the outcomes. Results, At 2 months, the proportion of patients reporting no or minimal dyspeptic symptoms ranged from 74% for those having early endoscopy to 55% for those on empirical therapy (P = 0.009), but at 1 year, there was little difference among the four strategies. Early endoscopy was associated with fewer subsequent consultations for dyspepsia (P = 0.003). ,Test and treat' resulted in fewer endoscopies overall and was most cost-effective over a range of cost assumptions. Empirical therapy resulted in the lowest initial costs, but the highest rate of subsequent endoscopy. Gastro-oesophageal cancers were found in four patients randomized to the H. pylori testing strategies. Conclusions, While early endoscopy offered some advantages ,Test and treat' was the most cost-effective strategy. In older patients, early endoscopy may be an appropriate strategy in view of the greater risk of malignant disease. [source] Coating selection and tribological testing for engineering equipment applicationsLUBRICATION SCIENCE, Issue 2 2008S.E. Franklin This paper considers the process of selecting and testing coatings for parts in professional engineering equipment applications in relation to the needs of design engineers in industry and the practical issues encountered. A methodology for pre-selection of potential coating solutions is discussed and consideration is given to the practical implementation of testing strategies in order to obtain results that are pertinent to the application. Two example case studies are described and the results are discussed in terms of their practical relevance and use. Copyright © 2007 John Wiley & Sons, Ltd. [source] Interventions to Promote Physical Activity Among African American WomenPUBLIC HEALTH NURSING, Issue 5 2002JoAnne Banks-Wallace The lack of routine physical activity among African American women places them at risk for negative health outcomes associated with inactivity. The number of studies focused on African American women has increased dramatically in the past decade. This review examined the intervention research literature testing strategies to increase activity among African American women. Eighteen studies with 1,623 subjects were retrieved. Diverse interventions, settings, and measures were reported. Common methodologic weaknesses included lack of randomization of subjects, single-group design, instruments without documented validity and reliability, significant attrition, and questionable timing of outcome variable measurement. Strategies to design and deliver culturally appropriate interventions are reviewed. Suggestions for future research, such as examining intragroup differences and communal resources, are provided. [source] Associations of Rural Residence With Timing of HIV Diagnosis and Stage of Disease at Diagnosis, South Carolina 2001-2005THE JOURNAL OF RURAL HEALTH, Issue 2 2010Kristina E. Weis PhD Abstract Context: Rural areas in the southern United States face many challenges, including limited access to health care services and stigma, which may lead to later HIV diagnosis among rural residents. Purpose: To investigate the associations of rural residence with timing of HIV diagnosis and stage of disease at diagnosis. Methods: Timing of HIV diagnosis was categorized as a diagnosis of acquired immune deficiency syndrome within 1 year of a first positive HIV test or HIV-only. Stage of disease was based on initial CD4+ T-cell count taken within 1 year of diagnosis. County of residence at HIV diagnosis was classified as urban if the population of the largest city was at least 25,000; it was classified as rural otherwise. Logistic regression was used to analyze timing of HIV diagnosis, and analysis of covariance was used to analyze stage of disease. Findings: From 2001 to 2005, 4,137 individuals were diagnosed with HIV infection. Of these, 1,129 (27%) were rural and 3,008 (73%) were urban residents. Among rural residents, 533 (47%) were diagnosed late, compared with 1,258 (42%) urban residents. Rural residents were significantly more likely to be diagnosed late (OR 1.19 [95% CI, 1.02-1.38]). Rural residence was associated with lower initial CD4+ T-cell count in crude analysis (P= .01) but not after adjustment (P > .05). Conclusions: Rural residence is a risk factor for late HIV diagnosis. This may lead to reduced treatment response to antiretroviral medications, increased morbidity and mortality, and greater HIV transmission risks among rural residents. New testing strategies are needed that address challenges to HIV testing and diagnosis specific to rural areas. [source] Alternative Methods for Developmental Toxicity TestingBASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 5 2006Aldert H. Piersma The aims of these investigations have been to reduce animal experimentation, to refine effect assessment and mechanistic studies, and to accelerate and simplify safety testing in an area of toxicology that uses relatively many animals. Many alternatives have been developed over the years with different compexities, using biologic material ranging from continuous cell lines to complete embryos. The validation of alternatives and their application in testing strategies is still in its infancy, although significant steps towards these aims are currently being made. The introduction of the genomics technology is a promising emerging area in developmental toxicity testing in vitro. Future application of alternatives in testing strategies for developmental toxicity may significantly gain from the inclusion of gene expression studies, given the unique programme of gene expression changes in embryonic and foetal development. [source] Costs and Risks of Segregating GM Wheat in CanadaCANADIAN JOURNAL OF AGRICULTURAL ECONOMICS, Issue 3 2006William W. Wilson An analytical model was developed to explore prospective costs and risks of alternative testing strategies for a marketing system in Canada which markets both genetically modified (GM) and Non-GM wheats. The problem is solved using stochastic optimization, base case results are defined, and sensitivities conducted to evaluate impacts of selected variables. Added costs include: testing, rejection, and a risk premium which is required for handlers to be indifferent between the current and the proposed dual system. Protocols would require testing at the point of loading at the primary elevator, and export elevator, and supplementing this information with some form of grower variety declaration. There are several sources of inherent risks in such a system. For buyers, the cumulative impact of these is the risk of receiving GM content in a Non-GM shipment. For sellers, it is the risk of having a Non-GM shipment rejected. For sellers, the risk of rejection was typically less than 2%, and for buyers, the risk was typically less than 0.02%. Nous avons élaboré un modèle analytique pour explorer les coûts et les risques potentiels de la mise en place de nouvelles stratégies pour analyser le grain si le Canada décidait de commercialiser du blé génétiquement modifié (GM) et du blé non génétiquement modifié (NGM). Le problème est résolu à l'aide d'une optimisation stochastique; des scénarios de référence sont définis et des tests de sensitivité sont effectués pour évaluer l'impact de variables sélectionnées. Les coûts supplémentaires comprennent les coûts d'analyses, les coûts liés au rejet ainsi qu'une prime de risque exigée pour que les manutentionnaires demeurent indifférents entre le système actuel et le système double proposé. Les protocoles obligeraient la tenue d'analyses au point de chargement du silo primaire ainsi qu'au silo terminal, auxquelles s'ajouterait une certaine forme de déclaration du céréaliculteur sur la variété. Ce genre de système comporte plusieurs sources de risques inhérents. Pour les acheteurs, l'impact cumulatif est le risque de recevoir un chargement de blé NGM contenant du blé GM. Pour les vendeurs, c'est le risque qu'un chargement de blé NGM soit rejeté. Pour les vendeurs, le risque de rejet était généralement inférieur à 2%, et pour les acheteurs, le risque était généralement inférieur à 0.02%. [source] Phylogenetics and Ecology: As Many Characters as Possible Should Be Included in the Cladistic Analysis,CLADISTICS, Issue 1 2001Philippe Grandcolas As many data as possible must be included in any scientific analysis, provided that they follow the logical principles on which this analysis is based. Phylogenetic analysis is based on the basic principle of evolution, i.e., descent with modification. Consequently, ecological characters or any other nontraditional characters must be included in phylogenetic analyses, provided that they can plausibly be postulated heritable. The claim of Zrzavý (1997, Oikos 80, 186,192) or Luckow and Bruneau (1997, Cladistics 13, 145,151) that any character of interest should be included in the analysis is thus inaccurate. Many characters, broadly defined or extrinsic (such as distribution areas), cannot be considered as actually heritable. It is argued that we should better care for the precise definition and properties of characters of interest than decide a priori to include them in any case in the analysis. The symmetrical claim of de Queiroz (1996, Am. Nat. 148, 700,708) that some characters of interest should better be excluded from analyses to reconstruct their history is similarly inaccurate. If they match the logical principles of phylogenetic analysis, there is no acceptable reason to exclude them. The different statistical testing strategies of Zrzavý (1997) and de Queiroz (1996) aimed at justifying inclusion versus exclusion of characters are ill-conceived, leading respectively to Type II and Type I errors. It is argued that phylogenetic analyses should not be constrained by testing strategies that are downstream of the logical principles of phylogenetics. Excluding characters and mapping them on an independent phylogeny produces a particular and suboptimal kind of secondary homology, the use of which can be justified only for preliminary studies dealing with broadly defined characters. [source] A Note on the Interdependence between Hypothesis Generation and Information Search in Conducting Analytical Procedures,CONTEMPORARY ACCOUNTING RESEARCH, Issue 2 2003Stephen K. Asare Abstract This study examines the linkage among the initial hypothesis set, the information search, and decision performance in performing analytical procedures. We manipulated the quality of the initial hypothesis set and the quality of the information search to investigate the extent to which deficiencies (or benefits) in either process can be remedied (or negated) by the other phase. The hypothesis set manipulation entailed inheriting a correct hypothesis set, inheriting an incorrect hypothesis set, or generating a hypothesis set. The information search was manipulated by providing a balanced evidence set to auditors (i.e., evidence on a range of likely causes including the actual cause - analogous to a standard audit program) or asking them to conduct their own search. One hundred and two auditors participated in the study. The results show that auditors who inherit a correct hypothesis set and receive balanced evidence performed better than those who inherit a correct hypothesis set and did their own search, as well as those who inherited an incorrect hypothesis set and were provided a balanced evidence set. The former performance difference arose because auditors who conducted their own search were found to do repeated testing of non-errors and truncated their search. This suggests that having a correct hypothesis set does not ensure that a balanced testing strategy is employed, which, in turn, diminishes part of the presumed benefits of a correct hypothesis set. The latter performance difference was attributable to auditors' failure to generate new hypotheses when they received evidence about a hypothesis that was not in the current hypothesis set. This demonstrates that balanced evidence does not fully compensate for having an initial incorrect hypothesis set. These findings suggest the need for firm training and/or decision aids to facilitate both a balanced information search and an iterative hypothesis generation process. [source] A new multimarker test for family-based association studiesGENETIC EPIDEMIOLOGY, Issue 1 2007Cyril S. Rakovski Abstract We propose a new multimarker test for family-based studies in candidate genes. We use simulations under different genetic models to assess the performance of competing testing strategies, characterized in this study as combinations of the following important factors: genes, statistical tests, tag single nucleotide polymorphisms (SNP) methods, number of tag SNPs and family designs. An ANOVA model is employed to provide descriptive summaries of the effects on power of the above-mentioned factors. We find that tag SNP methods, gene characteristics and family designs have minimal impact on the best testing strategy. The familywise error rate (FWER) controlling multiple comparison procedure and the new multimarker test offer the highest power followed by the asymptotic global haplotype test. Both the FWER and the multimarker test are invariant to family designs and gain power as we increase the number of tag SNPs. However, the performance of the global haplotype test is slightly degraded when analyzing larger numbers of tag SNPs. Within the framework of our study, the best strategy for family-based studies in candidate genes that emerged from our analysis is to use the FWER or the multimarker test and select 6,10 tag SNPs using any of the tag SNP methods considered. We confirm the conclusions of our study with an application to Alzheimer's disease data. Genet. Epidemiol. © 2006 Wiley-Liss, Inc. [source] Animal use replacement, reduction, and refinement: Development of an integrated testing strategy for bioconcentration of chemicals in fish,INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT, Issue 1 2007Watze de Wolf Abstract When addressing the use of fish for the environmental safety of chemicals and effluents, there are many opportunities for applying the principles of the 3Rs: Reduce, Refine, and Replace. The current environmental regulatory testing strategy for bioconcentration and secondary poisoning has been reviewed, and alternative approaches that provide useful information are described. Several approaches can be used to reduce the number of fish used in the Organization for Economic Cooperation and Development (OECD) Test Guideline 305, including alternative in vivo test methods such as the dietary accumulation test and the static exposure approach. The best replacement approach would seem to use read-across, chemical grouping, and quantitative structure-activity relationships with an assessment of the key processes in bioconcentration: Adsorption, distribution, metabolism, and excretion. Biomimetic extraction has particular usefulness in addressing bioavailable chemicals and is in some circumstances capable of predicting uptake. Use of alternative organisms such as invertebrates should also be considered. A single cut-off value for molecular weight and size beyond which no absorption will take place cannot be identified. Recommendations for their use in bioaccumulative (B) categorization schemes are provided. Assessment of biotransformation with in vitro assays and in silico approaches holds significant promise. Further research is needed to identify their variability and confidence limits and the ways to use this as a basis to estimate bioconcentration factors. A tiered bioconcentration testing strategy has been developed taking account of the alternatives discussed. [source] Strategy for applying genome-wide selection in dairy cattleJOURNAL OF ANIMAL BREEDING AND GENETICS, Issue 4 2006L.R. Schaeffer Summary Animals can be genotyped for thousands of single nucleotide polymorphisms (SNPs) at one time, where the SNPs are located at roughly 1-cM intervals throughout the genome. For each contiguous pair of SNPs there are four possible haplotypes that could be inherited from the sire. The effects of each interval on a trait can be estimated for all intervals simultaneously in a model where interval effects are random factors. Given the estimated effects of each haplotype for every interval in the genome, and given an animal's genotype, a ,genomic' estimated breeding value is obtained by summing the estimated effects for that genotype. The accuracy of that estimator of breeding values is around 80%. Because the genomic estimated breeding values can be calculated at birth, and because it has a high accuracy, a strategy that utilizes these advantages was compared with a traditional progeny testing strategy under a typical Canadian-like dairy cattle situation. Costs of proving bulls were reduced by 92% and genetic change was increased by a factor of 2. Genome-wide selection may become a popular tool for genetic improvement in livestock. [source] Pollinex® Quattro Ragweed: safety evaluation of a new allergy vaccine adjuvanted with monophosphoryl lipid A (MPL®) for the treatment of ragweed pollen allergyJOURNAL OF APPLIED TOXICOLOGY, Issue 4 2007Paul Baldrick Abstract A novel allergy vaccine (Pollinex® Quattro Ragweed) has been developed for the prevention or relief of allergic symptoms caused by pollen from Ambrosia spp. (ragweed). An extract from the pollen (chemically modified by glutaraldehyde) is adsorbed onto l -tyrosine with addition of the immunostimulatory adjuvant, monophosphoryl lipid A (MPL®). A specific preclinical safety testing strategy was developed to support clinical use and comprised reference to preclinical data available for the marketed non-MPL® adjuvanted form of the ragweed vaccine (Pollinex® R) and a new repeat dose toxicity study in the rat. Studies with Pollinex® R comprised single dose subcutaneous toxicity studies in mice and rats, repeat dose (10 injections over 20 days) parenteral toxicity studies in rats and dogs, an in vitro gene mutation assay along with single and multiple injection local tolerance studies in rats and dogs. The repeat dose subcutaneous toxicity study with Pollinex® Quattro Ragweed involved seven injections over 3 weeks (which was more aggressive than the four weekly doses used in the clinic) with dose levels of up to 0.5 ml per animal used. Overall, the product showed no toxicological findings of significance at levels greatly in excess of those proposed for clinical use. As is a feature with vaccination, some dose site irritation was seen. Copyright © 2007 John Wiley & Sons, Ltd. [source] Comparison of the performance of rapid HIV tests using samples collected for surveillance in Mozambique,JOURNAL OF MEDICAL VIROLOGY, Issue 12 2009Josefa Melo Abstract Mozambique had low HIV prevalence until the mid-1990s, but recent data indicate increasing rates. There is little information on HIV-2. Therefore, HIV seroprevalence was assessed among pregnant women and field-ready HIV diagnostic strategies were evaluated. A total of 6,930 samples collected by three health centers from 2002 to 2005 were tested on site by nurses with two simple/rapid tests, Determine HIV-1/2 (Abbott Laboratories; screening) and Uni-Gold HIV (Trinity Biotech; confirmation), which is the national HIV testing strategy. The prevalence of HIV was 14.0% (2002), 17.8% (2003), 16.5% (2004), and 20.2% (2005). A subset of 888 samples collected 2003 was sent to the Central Microbiology Laboratory, Maputo for evaluation of tests and testing strategies. The assays included for comparison were Capillus HIV-1/HIV-2 (Trinity Biotech), DoubleCheckGold HIV-1&2 (Orgenics) and Enzygnost Anti-HIV-1/2 Plus (Behringwerke, reference ELISA). Confirmation of reactive samples was done by Uni-Gold HIV and ImmunoComb II HIV-1&2 BiSpot (for HIV type differentiation). The Capillus HIV-1/ HIV-2,+,ImmunoComb II HIV-1&2 BiSpot combination was the gold standard. The sensitivity of the rapid/simple screening assays (Determine HIV-1/2, DoubleCheckGold HIV-1&2) was 100% (N,=,160) and their (initial) specificities were 99.6% and 99.7%, respectively. Repeated testing and combinations of assays increased the specificity. Four suspected cases of recent seroconversion were found. Together with the increasing prevalence rates, this may indicate that Mozambique is a high-incidence area, although further studies are needed to confirm this. Testing strategies for on-site screening and confirmation based on the combination of Determine HIV-1/2, Uni-Gold HIV and DoubleCheckGold HIV-1&2 are well suited for local field use. J. Med. Virol. 81:1991,1998, 2009. © 2009 Wiley-Liss, Inc. [source] On Business Cycle Asymmetries in G7 CountriesOXFORD BULLETIN OF ECONOMICS & STATISTICS, Issue 3 2004Khurshid M. Kiani Abstract We investigate whether business cycle dynamics in seven industrialized countries (the G7) are characterized by asymmetries in conditional mean. We provide evidence on this issue using a variety of time series models. Our approach is fully parametric. Our testing strategy is robust to any conditional heteroskedasticity, outliers, and/or long memory that may be present. Our results indicate fairly strong evidence of nonlinearities in the conditional mean dynamics of the GDP growth rates for Canada, Germany, Italy, Japan, and the US. For France and the UK, the conditional mean dynamics appear to be largely linear. Our study shows that while the existence of conditional heteroskedasticity and long memory does not have much effect on testing for linearity in the conditional mean, accounting for outliers does reduce the evidence against linearity. [source] Evaluation of the statistical power for multiple tests: a case studyPHARMACEUTICAL STATISTICS: THE JOURNAL OF APPLIED STATISTICS IN THE PHARMACEUTICAL INDUSTRY, Issue 1 2009Adeline Yeo Abstract It is challenging to estimate the statistical power when a complicated testing strategy is used to adjust for the type-I error for multiple comparisons in a clinical trial. In this paper, we use the Bonferroni Inequality to estimate the lower bound of the statistical power assuming that test statistics are approximately normally distributed and the correlation structure among test statistics is unknown or only partially known. The method was applied to the design of a clinical study for sample size and statistical power estimation. Copyright © 2008 John Wiley & Sons, Ltd. [source] Prenatal RHD gene determination and dosage analysis by PCR: clinical evaluationPRENATAL DIAGNOSIS, Issue 4 2001F.-Y. Chan Abstract Background , Use of the polymerase chain reaction (PCR) for detection of the RHD gene can measure the RHD gene status for unborn babies at risk for hemolytic disease of the newborn (HDN). The occurrence of D gene variants has led to errors in prenatal typing. Previous reports have highlighted the danger of assigning a positive fetus as negative, resulting in intrauterine fetal deaths. Objective , To evaluate the effectiveness of a testing strategy whereby PCR was not only performed to determine the presence/absence of the RHD gene, but also used to assess the D gene copy number (zero, one or two RHD genes) in family studies for at risk pregnancies. Methods , Samples comprising maternal (57) and paternal (42) peripheral blood samples, amniotic fluid (64), and matching cord blood (64) were collected. Rhesus (Rh) serotyping was performed on all blood samples. For RHD genotyping, DNA was extracted from all samples except for 28 cord samples, where only serotyping was performed (total 199 DNA genotyping). RHD gene PCR amplified exon 4 and exon 7 regions of the RHD gene. The dosage of RHD gene was determined by comparing the intensity of the RHD gene to that of the RHCE gene. Results , A total of 197/199 samples showed concordance between exon 4 and exon 7 PCR results. Two discrepant results occurred in one family: the father carried one normal D gene and one D gene variant where PCR was tested to be positive using exon 4 but negative using exon 7. One of a pair of dizygotic twins inherited this abnormal D gene and was mildly affected by HDN. This was correctly identified antenatally and the pregnancy successfully managed. The concordance rate between serotypes and genotypes for 135 blood samples was 100%. Amongst the family groups, 8/14 heterozygous fathers transmitted the D gene and 26/26 homozygous fathers transmitted the D gene to the babies. The concordance rate between RHD genotypes from amniotic fluid and Rh D serotypes from cord blood was also 100%. Conclusion , The present study demonstrates the effectiveness of using PCR in a clinical setting. It verifies the importance of testing more than one region of the gene, and also the need for a testing strategy where both maternal and paternal testing for RHD gene dosages are performed. Copyright © 2001 John Wiley & Sons, Ltd. [source] The role of ASTM E27 methods in hazard assessment part II: Flammability and ignitabilityPROCESS SAFETY PROGRESS, Issue 1 2005Laurence G. Britton Accurate flammability and ignitability data for chemicals form the cornerstone of procedures used to assess the hazards associated with commercial chemical production and use. Since 1967 the ASTM E27 Committee on the Hazard Potential of Chemicals has issued numerous, widely used consensus standards dealing with diverse testing and predictive procedures used to obtain relevant chemical hazard properties. The decision to issue a standard rests solely with the membership, which consists of representatives from industry, testing laboratories, consulting firms, government, academia, and instrument suppliers. Consequently, the procedures are automatically relevant, timely, and widely applicable. The purpose of this paper is to highlight some of the widely used standards, complemented with hypothetical but relevant examples describing the testing strategy, interpretation, and application of the results. A further goal of this paper is to encourage participation in the consensus standards development process. The paper is published in two parts. The first part (in the preceding issue of Process Safety Progress) dealt with the E27 standards pertaining to thermodynamics, thermal stability, and chemical compatibility. The second part, published here, focuses on the flammability, ignitability, and explosibility of fuel and air mixtures. © 2005 American Institute of Chemical Engineers Process Saf Prog, 2005 [source] Optimum step-stress for temperature accelerated life testingQUALITY AND RELIABILITY ENGINEERING INTERNATIONAL, Issue 8 2007Evans Gouno Abstract Step-stress accelerated life testing is a design strategy where the stress is modified several times during the test. In this work we address the problem of designing such a test. We focus on temperature accelerated life testing and we address the problems of setting the step duration and the stress levels. Assuming an Arrhenius model, maximum likelihood estimates of the parameters are computed. Relying on the properties of these estimators we compare different criteria for assessing the optimality of the plans produced. Some tables are presented to illustrate the method. For a fixed number of steps and a set of temperatures, a table of optimal length steps can be computed. For fixed step lengths, sets of temperatures leading to optimal plans are also available. Thus, this work provides useful tools to help engineers make decisions in testing strategy. Copyright © 2007 John Wiley & Sons, Ltd. [source] | |||||||||||||||||||||||||