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Standard Tests (standard + test)

Distribution by Scientific Domains

Medical Sciences	51%
Life Sciences	14%
Earth and Environmental Science	8%
Business, Economics, Finance and Accounting	8%
Engineering	5%
Chemistry	5%
2 Other Domains	9%

Distribution within Medical Sciences

Neurology	15%
Radiology & Imaging	9%

Kinds of Standard Tests

gold standard test

Terms modified by Standard Tests

standard test problem

Selected Abstracts

Measurement of the setting expansion of phosphate-bonded investment materials: Part I , Development of the Casting-Ring Test

JOURNAL OF ORAL REHABILITATION, Issue 7 2004
C. H. Lloyd
summary, The setting expansion is an important property for a phosphate-bonded investment material. This research was undertaken to investigate a test that might be suitable for its measurement when used in a Standard. In the ,Casting-Ring Test', the investment sample is contained in a steel ring and expands to displace a precisely positioned pin. Variables with the potential to alter routine reproduction of the value were investigated. The vacuum-mixer model is a production laboratory variable that must not be ignored and for this reason, experiments were repeated using a different vacuum-mixer located at a second test site. Restraint by the rigid ring material increased expansion, while force on the pin reduced it. Expansion was specific to the lining selected. Increased environmental temperature decreased the final value. Expansion was still taking place at a time at which its value might be measured. However, when these factors are set, the reproducibility of values for setting expansion was good at both test sites (coefficient of variation 14%, at most). The results revealed that with the control that is available reliable routine measurement is possible in a Standard test. The inter-laboratory variable, vacuum-mixer model, produced significant differences and it should be the subject of further investigation. [source]

The Long-Run Relationship between House Prices and Income: Evidence from Local Housing Markets

REAL ESTATE ECONOMICS, Issue 3 2006
Joshua Gallin
Many in the housing literature argue that house prices and income are cointegrated. I show that the data do not support this view. Standard tests using 27 years of national-level data do not find evidence of cointegration. However, standard tests for cointegration have low power, especially in small samples. I use panel-data tests for cointegration that are more powerful than their time-series counterparts to test for cointegration in a panel of 95 metro areas over 23 years. Using a bootstrap approach to allow for cross-correlations in city-level house-price shocks, I show that even these more powerful tests do not reject the hypothesis of no cointegration. Thus the error-correction specification for house prices and income commonly found in the literature may be inappropriate. [source]

Measurement of the setting expansion of phosphate-bonded investment materials: Part II , An evaluation of the Casting-Ring Test at 10 laboratories

JOURNAL OF ORAL REHABILITATION, Issue 7 2004
C. H. Lloyd
summary, The Casting-Ring Test has the potential to fulfil the requirement for a reliable ,Standard' test to measure the setting expansion of phosphate-bonded investment materials. The purpose of this study was to investigate the reproducibility of the measurements and the value that is produced at 10 test sites. The Casting-Ring Test apparatus, three phosphate-bonded investment products and one ring liner product were sent to the 10 participants, together with a detailed test protocol. Participants were asked to use their normal vacuum mixers. Reproducibility at individual sites was good. However, there were significant differences between test sites for the mean setting expansions, attributed to the range of vacuum mixers employed. From these results, the Casting-Ring Test appears to satisfy the requirements for adoption as an ISO standard test. The effect produced by different vacuum-mixer models would be manifest in any test. Not only does this have implications when determining the value of setting expansion for product information, but such a range of setting expansions will also be reproduced during production of moulds in commercial dental laboratory practice. However, for any specific product and vacuum-mixer combination, the setting expansion will be consistent and will not vary from mould to mould. [source]

Assessing immunophenotyping performance: Proficiency-validation for adopting improved flow cytometry methods

CYTOMETRY, Issue 4 2007
Lance E. Hultin
Abstract Background: The continuous improvement and evolution of immune cell phenotyping requires periodic upgrading of laboratory methods and technology. Flow cytometry laboratories that are participating in research protocols sponsored by the NIAID are required to perform "switch" studies to validate performance before methods for T-cell subset analysis can be changed. Methods: Switch studies were conducted among the four flow cytometry laboratories of the Multicenter AIDS Cohort Study (MACS), comparing a 2-color, lyse-wash method and a newer, 3-color, lyse no-wash method. Two of the laboratories twice failed to satisfy the criteria for acceptable differences from the previous method. Rather than repeating more switch studies, these laboratories were allowed to adopt the 3-color, lyse no-wash method. To evaluate the impact of the switch to the new method at these two sites, their results with the new method were evaluated within the context of all laboratories participating in the NIH-NIAID-Division of AIDS Immunology Quality Assurance (IQA) proficiency-testing program. Results: Laboratory performance at these two sites substantially improved relative to the IQA standard test results. Variation across the four MACS sites and across replicate samples was also reduced. Conclusions: Although switch studies are the conventional method for assessing comparability of laboratory methods, two alternatives to the requirement of repeating failed switch studies should be considered: (1) test the new method and assess performance on the proficiency testing reference panel, and (2) prior to adoption of the new methods, use both the old and the new method on the reference panel samples and demonstrate that performance with the new method is better according to standard statistical procedures. These alternatives may help some laboratories' transition to a new and superior methodology more quickly than if they are required to attempt multiple, serial switch studies. © 2007 Clinical Cytometry Society [source]

Diagnostic accuracy of digitized periapical radiographs validated against micro-computed tomography scanning in evaluating orthodontically induced apical root resorption

EUROPEAN JOURNAL OF ORAL SCIENCES, Issue 5 2008
Alexander Dudic
The aim of this study was to validate the use of digitized periapical radiographs in evaluating orthodontically induced apical root resorption against micro-computed tomography (micro-CT) scanning as a criterion standard test. In a standardized experimental protocol, 29 premolars in 16 subjects were tipped buccally for 8 wk. Nineteen contralateral premolars not subjected to orthodontic movement served as controls. Standardized periapical radiographs were taken before and after the experimental period (Rx method). These teeth were extracted and scanned using a micro-CT technique with a 9 ,m resolution. Two calibrated examiners assessed blindly the presence or absence of apical root resorption on digitized radiographs and three-dimensional reconstructions of the scans. Significant differences were detected between the orthodontically moved teeth and controls: 86% of the orthodontically moved teeth and 21% of the control teeth showed apical root resorption when using micro-CT as a validation method. A total of 55% of the experimental teeth and 5% of the control teeth showed resorption when assessed using Rx method. The Rx method showed a specificity of 78% and a sensitivity of 44%, which means that less than half of the cases with root resorption identified using a CT scanner were identified by radiography. Nearly all the orthodontically moved teeth showed apical root resorption. Apical root resorption may be underestimated when evaluated using digitized periapical radiographs. [source]

Robustness of a 3 min all-out cycling test to manipulations of power profile and cadence in humans

EXPERIMENTAL PHYSIOLOGY, Issue 3 2008
Anni Vanhatalo
The purpose of this study was to assess whether end-test power output (EP, synonymous with ,critical power') and the work done above EP (WEP) during a 3 min all-out cycling test against a fixed resistance were affected by the manipulation of cadence or pacing. Nine subjects performed a ramp test followed, in random order, by three cadence trials (in which flywheel resistance was manipulated to achieve end-test cadences which varied by ,20 r.p.m.) and two pacing trials (30 s at 100 or 130% of maximal ramp test power, followed by 2.5 min all-out effort against standard resistance). End-test power output was calculated as the mean power output over the final 30 s and the WEP as the power,time integral over 180 s for each trial. End-test power output was unaffected by reducing cadence below that of the ,standard test' but was reduced by ,10 W on the adoption of a higher cadence [244 ± 41 W for high cadence (at an end-test cadence of 95 ± 7 r.p.m.), 254 ± 40 W for the standard test (at 88 ± 6 r.p.m.) and 251 ± 38 W for low cadence (at 77 ± 5 r.p.m.)]. Pacing over the initial 30 s of the test had no effect on the EP or WEP estimates in comparison with the standard trial. The WEP was significantly higher in the low cadence trial (16.2 ± 4.4 kJ) and lower in the high cadence trial (12.9 ± 3.6 kJ) than in the standard test (14.2 ± 3.7 kJ). Thus, EP is robust to the manipulation of power profile but is reduced by adopting cadences higher than ,standard'. While the WEP is robust to initial pacing applied, it is sensitive to even relatively minor changes in cadence. [source]

Non-invasive markers for the prediction of fibrosis in chronic hepatitis C infection

HEPATOLOGY RESEARCH, Issue 8 2008
Timothy Cross
Liver fibrosis occurs as a result of chronic liver injury and is the hallmark of chronic liver disease. The final stage of progressive liver fibrosis is cirrhosis, which is implicated in portal hypertension, end-stage liver disease and hepatocellular carcinoma. Liver biopsy has historically been the gold standard test for the assessment of liver fibrosis for liver diseases such as viral hepatitis, autoimmune hepatitis and primary biliary cirrhosis. Improved serological tests have enhanced the diagnosis of these conditions and reduced the need for liver biopsy. Liver biopsy is unpopular among patients and clinicians. It is associated with morbidity and mortality, and in addition is subject to sampling error, inter- and intra-observer variability. There is therefore a need for non-invasive markers of liver fibrosis that are accurate, reliable, cheap and easy to use. The aim of this review is to examine the different non-invasive methods that can be used to estimate the severity of fibrosis. The methods evaluated include clinical examination, routine laboratory investigations, imaging tests, specialized tests of liver function and finally serum extra-cellular matrix markers of fibrosis. The review mainly focuses on fibrogenesis in the context of chronic hepatitis C infection. [source]

Involuntary, unreinforced (pure) spatial learning is impaired by fimbria-fornix but not by dorsal hippocampus lesions

HIPPOCAMPUS, Issue 3 2003
Norman M. White
Abstract Pure spatial learning occurs when rats acquire information about an environment while exploring it in the absence of reinforcers. We previously reported that voluntary, unreinforced exploration of a radial maze retards subsequent reinforced conditioned cue preference (CCP) learning in the same maze. In the present experiment, we examined the effects of involuntary, unreinforced pre-exposure to a radial maze. During pre-exposure, rats were moved by an experimenter between the ends of two arms of a radial maze five times in 30 min. This form of pre-exposure retarded CCP learning, whereas rats that were not pre-exposed and rats that were pre-exposed to a maze in a different room displayed normal CCP learning. These findings suggest that some information specific to the maze environment was acquired during involuntary unreinforced pre-exposure to it. In experiment 2, the retardation of reinforced CCP learning by involuntary unreinforced pre-exposure was eliminated by fimbria-fornix lesions made before pre-exposure but was unaffected by fimbria-fornix lesions made after pre-exposure but before training. Large neurotoxic lesions of the dorsal hippocampus made before pre-exposure had no effect on the retardation of CCP learning, but the rats with these lesions were impaired on a standard test of reinforced spatial learning in a water maze. The lesion effects in experiment 2 are similar to those previously reported for voluntary exploration and suggest that pure spatial learning may occur during both voluntary exploration of and involuntary exposure to an environment in the absence of reinforcers. Pure spatial learning can apparently occur with exposure to two different locations within an environment, but the rats do not have to move between the locations voluntarily. An intact fimbria-fornix is required for acquisition but not expression of this form of learning. The hippocampus is not involved in this form of learning. Hippocampus 2003;13:324,333. © 2003 Wiley-Liss, Inc. [source]

Reliability of a telephone-administered cognitive test battery (TACT) between telephone and face-to-face administration

INTERNATIONAL JOURNAL OF METHODS IN PSYCHIATRIC RESEARCH, Issue 1 2001
Neil R. Thompson
Abstract We have previously described the development and initial validation of a telephone administered cognitive test battery (TACT). This report investigates the retest reliability of the TACT battery between telephone administration and face-to-face administration and measures the concurrent validity of the test components against a standard test of cognitive ability, the WAIS-RUK. Data were collected on 27 participants aged 62,63 years. There was a two- to 10-month interval between time 1 (telephone) and time 2 (face-to-face) administration. Intra-class correlation coefficients for telephone versus face-to-face administration of the TACT were satisfactory for all component measures except for ,object rotation' and WAIS similarities. There was no evidence of systematic cheating on the telephone-administered test. Tests of concurrent validity showed stronger correlations for the TACT battery components with verbal tests rather than performance tests, as measured by the WAIS-RUK. A few administration difficulties are noted and recommendations for change are outlined. The TACT is a convenient assessment tool with potential for measuring cognitive change in epidemiological studies. Copyright © 2001 Whurr Publishers Ltd. [source]

Measurement of the setting expansion of phosphate-bonded investment materials: Part II , An evaluation of the Casting-Ring Test at 10 laboratories

Laboratory identification of lupus anticoagulants,

AMERICAN JOURNAL OF HEMATOLOGY, Issue 7 2009
Kristi J. Smock
Lupus anticoagulants (LA) are acquired autoantibodies that can cause antiphospholipid syndrome. LAs prolong phospholipid-dependent coagulation tests, acting as nonspecific inhibitors that are neutralized in the presence of excess phospholipid. However, there is no gold standard test and the testing is influenced by a number of variables. This article summarizes laboratory testing for LAs, with particular focus on technical issues and limitations of testing. Am. J. Hematol. 2009. © 2009 Wiley-Liss, Inc. [source]

The effect of a prior cognitive interview on children's acceptance of misinformation

APPLIED COGNITIVE PSYCHOLOGY, Issue 4 2003
Robyn E. Holliday
This research examined whether a Cognitive interview facilitates correct recall in children aged 4 to 5 and 9 to 10 years, and whether a Cognitive interview given before post-event misinformation reduces children's reporting of suggestions on subsequent memory tests. Children were presented with an event followed the next day by a Cognitive or a Memorandum interview. Children were then read a post-event summary containing misleading suggestions. The next day all children were given both standard test and modified forced-choice cued-recall tests. The free recall phase of the Cognitive interview elicited the greatest number of correct details. Age differences were found such that 9- to 10-year-old children's reports were more accurate and more complete than those of the 4- to 5-year-olds. More correct person, action and object details were reported in a Cognitive interview. Misinformation effects were found in both age groups on the standard test whereas on the modified test such an effect was only found in the 4- to 5-year-olds. Children's reporting of suggestions was unaffected by prior interview. Copyright © 2003 John Wiley & Sons, Ltd. [source]

A standard test for AGCMs including their physical parametrizations: I: the proposal

ATMOSPHERIC SCIENCE LETTERS, Issue 2 2000
R. B. Neale
Abstract To assist model intercomparison and development of a set of eight numerical experiments is proposed as a test-bed for the interaction of dynamics and physical parameterizations in atmospheric GCMs. The framework for the experiments is that of an aqua-planet and the prescribed sea-surface temperatures (SSTs) are highly idealized. Copyright © 2001 Royal Meteorological Society. [source]

A standard test for AGCMs including their physical parametrizations.

ATMOSPHERIC SCIENCE LETTERS, Issue 2 2000
II: results for the Met Office Model
Abstract Example results are shown for the proposed aqua-planet experiments using a version of The Met Office Unified Model (UM). The zonal mean circulation exhibits strong sensitivity to the latitudinal distribution of sea-surface temperatures (SST). Longitudinal variation of SST yields information on the linearity and distribution of the convective response. Copyright © 2001 Royal Meteorological Society. [source]

Knowledge and practical performance gained by Iraqi residents after participation to a neonatal resuscitation program course

ACTA PAEDIATRICA, Issue 8 2009
Maysoon M Jabir
Abstract Aim:, neonatal resuscitation program (NRP) course is effective in improving knowledge in participants coming from developed as well as developing countries; however, its impact on practical performances has not been yet formally evaluated in participants coming from developing countries. We evaluate the knowledge and the performance on clinical simulations gained by Iraqi residents following participation in the NRP course. Methods:, A 71-item questionnaire derived from the standard test contained in the American Heart Association and American Academy of Pediatrics Neonatal Resuscitation Manual was administered to participants before and after the course. All participants were tested with a final Mega code (Mega code A scenario,NRP textbook) to evaluate their performance on clinical simulations. Results:, Twenty-six obstetrical and 2 pediatric residents participated in the NRP course, respectively. The percentages of correct answers significantly improved from before (52 ± 14%) to immediately after the course (85 ± 7%); p < 0.001. Mean score obtained at the final Mega code was 68 ± 8%. Four out of 28 (14%) participants reached the minimum score required for passing the exam (80%). Conclusion:, Residents coming from a developing country (Iraq) significantly improved their knowledge attainment following participation in the NRP course; however, their performance on clinical simulations was unsatisfactory, suggesting that this aspect needs to be improved. [source]

The role of desmopressin in bilateral and simultaneous inferior petrosal sinus sampling for differential diagnosis of ACTH-dependent Cushing's syndrome

CLINICAL ENDOCRINOLOGY, Issue 1 2007
Marcio Carlos Machado
Summary Objective, ,Bilateral inferior petrosal sinus sampling (BIPSS) with corticotrophin-releasing hormone (CRH) stimulation is currently the gold standard test for the differential diagnosis of ACTH-dependent Cushing's syndrome. Reports on the use of desmopressin in this approach are limited. The aim of this study was to evaluate the use of desmopressin during BIPSS in a cohort of patients with ACTH-dependent Cushing's syndrome. Design, ,A retrospective case-record study. Patients,, Fifty-six patients with confirmed ACTH-dependent Cushing's syndrome underwent BIPSS with desmopressin stimulation when presenting negative pituitary tumour imaging. Measurements,, Central to peripheral (CEN:PER) ACTH gradient, lateralization of the ACTH source and surgical tumour confirmation were evaluated. Results,, A CEN:PER ACTH gradient was found in 40 patients under basal conditions (CEN:PER , 2) and in 47 patients after desmopressin stimulation (CEN:PER , 3). Ectopic ACTH-producing tumours (three lung carcinoid tumour, one thymus carcinoid tumour and one thymus hyperplasia) were confirmed in five out of nine patients without the CEN:PER ACTH gradient, and four cases were false negative for Cushing's disease. Lateralization (IPS:IPS , 1·4) was observed in 80·8% of patients under basal conditions (38/47) and in 97·8% after desmopressin (46/47), and it was surgically confirmed in 78·7%. There were no false-positive cases. Sensitivity and specificity were 92·1% and 100%, respectively. Conclusions, ,Desmopressin improves the differential diagnosis of ACTH-dependent Cushing's syndrome by amplifying the CEN:PER and IPS:IPS ACTH gradients, and is therefore a useful ACTH secretagogue in BIPSS. [source]

Robustness of a 3 min all-out cycling test to manipulations of power profile and cadence in humans

Identification of low-dye-binding (ldb) mutants of Saccharomyces cerevisiae

FEMS YEAST RESEARCH, Issue 4-5 2004
Isaac Corbacho
ldb, low-dye-binding; mnn, mannan-defective; MP, mannosylphosphate Abstract We have completed the identification of Saccharomyces cerevisiae genes that are defective in previously isolated ldb (low-dye-binding) mutants. This was done by complementation of the mutant's phenotype with DNA fragments from a genomic library and by running standard tests of allelism with single-gene deletion mutants of similar phenotype. The results were as follows: LDB2 is allelic to ERD1; LDB4 to SPC72; LDB5 to RLR1; LDB6 to GON7/YJL184W; LDB7 to YBL006C; LDB9 to ELM1; LDB10 to CWH36; LDB11 to COG1; LDB12 to OCH1; LDB13 to VAN1; LDB14 to BUD32; and LDB15 to PHO85. Since the precise function of some of the genes is not known, these data may contribute to the functional characterization of the S. cerevisiae genome. [source]

Novel approaches to assessing renal function in cirrhotic liver disease

HEPATOLOGY RESEARCH, Issue 9 2007
Andrew J. Portal
Renal dysfunction is common in patients with end-stage liver disease. Etiological factors include conditions as diverse as acute tubular necrosis, immunoglobulin A nephropathy and hepatorenal syndrome. Current standard tests of renal function, such as measurement of serum urea and creatinine levels, are inaccurate as the synthesis of these markers is affected by the native liver pathology. This article reviews novel markers of renal function and their potential use in patients with liver disease. [source]

Using faecal elastase-1 to screen for chronic pancreatitis in patients admitted with acute pancreatitis

HPB, Issue 3 2006
R.C. Turner
Abstract Background: Patients presenting with acute pancreatitis may have co-existing chronic pancreatitis, the accurate diagnosis of which would potentially guide appropriate management. Gold standard tests are often invasive, costly or time-consuming, but the faecal elastase-1 assay has been shown to be comparatively accurate for moderate and severe exocrine deficiency. This study aimed to evaluate fecal elastase-1 concentration [FE-1] against clinical criteria for chronicity in an acute setting. Patients and methods: [FE-1] was performed on patients admitted with acute onset of epigastric pain and a serum lipase at least three times the upper limit of normal. Clinical diagnosis of chronic pancreatitis was defined by the presence of specific clinical, pathological or radiological criteria. A [FE-1] value of <200 µg/g was similarly considered indicative of chronic exocrine insufficiency. Thus a 2×2 table comparing [FE-1] and clinical diagnosis was constructed. Results: After exclusion of liquid stool specimens, 105 stool specimens from 87 patients were suitable for [FE-1] determination. [FE-1] was evaluated against the clinical diagnosis of chronic pancreatitis, initially for the whole sample, and then after exclusion of cases of moderate and severe acute pancreatitis (Ranson score >2). The latter analysis, based on an exocrine insufficiency threshold of 200 µg/g, yielded a sensitivity of 79.5%, specificity of 98.0%, positive predictive value of 96.9% and negative predictive value of 86.0%. Conclusion: [FE-1] is an accurate screening tool for underlying chronic exocrine insufficiency when taken in the course of a hospital admission for mild acute pancreatitis. [source]

Fecal S100A12 and fecal calprotectin as noninvasive markers for inflammatory bowel disease in children

INFLAMMATORY BOWEL DISEASES, Issue 3 2008
Marc A. Sidler MD
Abstract Background: Fecal calprotectin is a sensitive marker for gut inflammation. Recently, we have established that a related protein, S100A12, is elevated in the feces of children with inflammatory bowel disease (IBD). This may represent a specific and sensitive disease marker. The objective was to investigate the utility of fecal S100A12, in comparison to fecal calprotectin and standard inflammatory markers, as a screening marker for IBD in children with gastrointestinal symptoms. Methods: Stool samples were obtained from 61 children presenting with gastrointestinal symptoms requiring endoscopy. Fecal S100A12, calprotectin, and serum S100A12 levels were measured and correlated to final diagnosis and standard tests (ESR, CRP, platelet count, and albumin). Results: Children diagnosed with IBD (n = 31) had elevated fecal S100A12 (median 55.2 mg/kg) and calprotectin (median 1265 mg/kg) levels compared with the children without IBD (n = 30; S100A12: median 1.1 mg/kg, P < 0.0001; calprotectin: median 30.5 mg/kg; P < 0.0001). The sensitivity and specificity of fecal S100A12 (cutoff 10 mg/kg) for the detection of IBD were both 97%, whereas fecal calprotectin (cutoff 50 mg/kg) gave a sensitivity of 100% and a specificity of 67%. Conclusions: Both fecal markers were superior to the sensitivities and specificities of any standard inflammatory test. Both fecal S100A12 and calprotectin are sensitive markers of gastrointestinal inflammation, but fecal S100A12 provided exceptional specificity in distinguishing children with IBD from children without IBD. Fecal S100A12 is a simple, noninvasive test that can be used to screen and select children warranting further invasive and laborious procedures such as endoscopy for the investigation of their gastrointestinal symptoms. (Inflamm Bowel Dis 2007) [source]

A coupled damage,plasticity model for concrete based on thermodynamic principles: Part I: model formulation and parameter identification

INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 4 2008
Giang D. Nguyen
Abstract The development of a coupled damage-plasticity constitutive model for concrete is presented. Emphasis is put on thermodynamic admissibility, rigour and consistency both in the formulation of the model, and in the identification of model parameters based on experimental tests. The key feature of the thermodynamic framework used in this study is that all behaviour of the model can be derived from two specified energy potentials, following procedures established beforehand. Based on this framework, a constitutive model featuring full coupling between damage and plasticity in both tension and compression is developed. Tensile and compressive responses of the material are captured using two separate damage criteria, and a yield criterion with a multiple hardening rule. A crucial part of this study is the identification of model parameters, with these all being shown to be identifiable and computable based on standard tests on concrete. Behaviour of the model is assessed against experimental data on concrete. Copyright © 2007 John Wiley & Sons, Ltd. [source]

An analytical and experimental analysis of a very fast thermal transient

INTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 11 2001
C. Aprea
Abstract According to some international standards, some products, developed for use under heavy thermal conditions, have to be tested by subjecting them for a short time to a particular heating and cooling thermal stress to allow them an acceptable future operative life. It is possible to obtain these fast thermal gradients in confined environments, called climatic chambers where the air is heated by an electrical resistance and is cooled with a finned evaporator which is linked to a vapour compression system subjected to a particular control system of the refrigerating power. In particular, in this paper the air and object tested thermal transients are studied from an analytical and experimental point of view. The study of the mathematical model is realized assuming simplified hypotheses about the air, the object and the air cooled evaporator temperature. The most complex circumstances are related to a very fast temperature decrease because under this working condition the mathematical model is characterized by a nonlinear differential system. The nonlinear term is represented by the refrigerating power that varies in a definite range with the evaporator temperature according to a sinusoid trend. For this power a suitable analytical expression, derived by the control system performance and by the compressor characteristic, has been found. The analytical,experimental comparison during a cooling thermal stress of typical products subjected to international standard tests as the electronic boards, has been carried out showing acceptable results. The model presented is useful to foresee the climatic chamber performances in the presence of a specific refrigerating power trend; this is the start-point for the design of the vapour compression plant and its control system. Copyright © 2001 John Wiley & Sons, Ltd. [source]

Independent comparative study of PCA, ICA, and LDA on the FERET data set

INTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY, Issue 5 2005
Kresimir Delac
Abstract Face recognition is one of the most successful applications of image analysis and understanding and has gained much attention in recent years. Various algorithms were proposed and research groups across the world reported different and often contradictory results when comparing them. The aim of this paper is to present an independent, comparative study of three most popular appearance-based face recognition projection methods (PCA, ICA, and LDA) in completely equal working conditions regarding preprocessing and algorithm implementation. We are motivated by the lack of direct and detailed independent comparisons of all possible algorithm implementations (e.g., all projection,metric combinations) in available literature. For consistency with other studies, FERET data set is used with its standard tests (gallery and probe sets). Our results show that no particular projection,metric combination is the best across all standard FERET tests and the choice of appropriate projection,metric combination can only be made for a specific task. Our results are compared to other available studies and some discrepancies are pointed out. As an additional contribution, we also introduce our new idea of hypothesis testing across all ranks when comparing performance results. © 2006 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 15, 252,260, 2005 [source]

Performance-Based Measures of Physical Function for High-Function Populations

JOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 5 2006
J. David Curb MD
OBJECTIVES: To improve and broaden the applicability of performance-based measures of function for use in clinical and research settings. DESIGN: Cross-sectional repeated-measures study. SETTING: Research clinic. PARTICIPANTS: Population-based sample of Japanese Americans without significant functional impairments aged 35 to 55 and 56 to 71 (N=203). MEASUREMENTS: Performance-based measures of physical function, including range of standard tests, newer automated measures of balance and strength and data on cognitive function, lifestyle, medical history, and physical activity. RESULTS: Of the nonplatform balance measures, only the one-leg stand was reliable (reliability coefficient (rc) =0.69) and able to discriminate between functional levels. Combining the Fourth National Health and Nutrition Examination Survey protocol of folded arm position while standing on a foam pad with the more-sophisticated balance platform test had the highest reliability and discrimination. With the strength chair, high rcs (0.88,0.96) were found for upper and lower extremity tests. Timed chair stands, a test of lower extremity and central strength were reliable. The 6-minute walk had a high rc (0.90). CONCLUSION: Many performance tests used today are not reliable. Only a few discriminate between the most highly functioning individuals and individuals with good function. Thus, a new recommended battery includes unassisted single-leg stand, balance platform "foam pad, eyes closed," elbow flexion and knee extension strength (strength chair), grip strength, timed chair stands, and the 6-minute walk. These simple performance-based tests have good reliability and discrimination across the range of function and can be used in most clinical and research settings to quickly assess global functional level. [source]

Parabens, oestrogenicity, underarm cosmetics and breast cancer: a perspective on a hypothesis

JOURNAL OF APPLIED TOXICOLOGY, Issue 5 2003
Philip W. Harvey
Abstract A recent review by Darbre (2003) published in this journal (J. Appi. Toxicol. 23: 89,95) has attracted public and scienti,c interest that requires perspective, particularly on the use of esters of p -hydroxybenzoic acid (parabens) as preservatives in underarm cosmetics. Although parabens are generally regarded as safe, recent reports suggest that they are oestrogenic in a variety of in vitro (including MCF7 and ZR-75-1 human breast cancer cell lines) and in vivo tests for oestrogenicity (uterotrophic assays in both rat and mouse). There are also recent reports of adverse reproductive and developmental outcomes in rodent toxicity studies. Of interest is the lack of activity by the oral route but clear activity by the subcutaneous and topical routes, which is of some relevance to the use of underarm cosmetics. There would seem to be a case now to supplement these emerging toxicity data with longer term regulatory standard tests examining other oestrogenic endpoints and at least to consider these ,ndings in more up-to-date risk assessments speci,c for cosmetic use. Further, there are few data on the use of underarm cosmetics and the risk of breast cancer, and although one recent retrospective interview-based study found no association there is a need for more thorough investigation taking into account the type of chemicals used. Darbre has forwarded a hypothesis and called for further work to establish whether or not the use of underarm cosmetics (particularly containing oestrogenic formulants) contributes to the rising incidence of breast cancer. It would seem prudent to conduct this work because the current database is sparse and the effects of long-term low-level exposures to weakly oestrogenic chemicals on human health, particularly their application to the underarm and the risks of breast cancer, are unknown. The role of oestrogens in breast cancer, however, is undisputed. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Assessment of the dyeing properties of pigments from Monascus purpureus

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 9 2005
Diana De Santis
Abstract Monascus purpureus C322 was cultivated on well-established production media to yield prevailingly red or orange pigment-rich ethanolic extracts. Once these extracts had been diluted by an overall factor of 50, they were used as such to dye raw wool standard specimens differently premordanted using alum or stannic chloride. Independently of the mordant used, the specimens dyed with the red pigment-rich extracts showed a pale red colour tending to pink, whereas the specimens dyed with the orange pigment-rich extracts exhibited a more definite orange colour. By carrying out a few colourfastness standard tests (manual washing at 40 °C, acid and basic perspiration and hot pressing), stannic chloride-premordanted wool specimens dyed with the red pigment-rich extracts were found to be less resistant to acid and basic perspiration than their orange counterparts. Since the production of the orange pigment-rich ethanolic extracts appeared to be more cost-effective than that of their red counterparts, the former might support the present demand for colorants of natural origin in the textile sector. Copyright © 2005 Society of Chemical Industry [source]

Renal sonography in the diagnosis of renal obstruction or hydronephrosis in patients with cervical cancer

JOURNAL OF CLINICAL ULTRASOUND, Issue 7 2002
Verna Vanderpuye MBCHB
Abstract Purpose The aim of this prospective study was to evaluate the role of renal sonography and its use as an alternative to intravenous urography in detecting ureteral obstruction or hydronephrosis in patients with cervical cancer. Materials and Methods Patients with biopsy-confirmed carcinoma of the cervix who were referred to the radiotherapy center from February 6, 2001, through July 20, 2001, were enrolled in this trial. All patients had previously undergone clinical staging by physical examination and either intravenous urography or CT scanning as the standard tests for diagnosing ureteral obstruction or hydronephrosis. All patients underwent renal sonography as an alternative diagnostic tool for diagnosing ureteral obstruction or hydronephrosis. Results Forty patients were enrolled. Their mean age was 46 years (range, 26,65 years). According to the FIGO staging system, 12% of the patients had clinical stages 1B2 and 2A disease, 20% had stage 2B, 8% had stage 3A, 50% had stage 3B, and 10% had a postoperative recurrence of cervical cancer. Thirty-four patients had had intravenous urography and 6 had had CT scans of the abdomen and pelvis. Sensitivity, specificity, positive and negative predictive values and overall accuracy rates for renal sonography were 76.5% (13/17), 100% (23/23), 100% (13/13), 85% (23/27), and 90% (36/40), respectively. Seventy-five percent (3/4) of the false-negative results occurred in patients with pelvic sidewall thickening on physical examination. Conclusions Renal sonography may be used as an effective and relatively low-cost means of diagnosing ureteral obstruction in patients with cervical cancer without clinically evident pelvic sidewall thickening. © 2002 Wiley Periodicals, Inc. J Clin Ultrasound 30:424,427, 2002 [source]

Validating multiple-period density-forecasting models

JOURNAL OF FORECASTING, Issue 4 2007
Kevin Dowd
Abstract This paper examines the problem of how to validate multiple-period density forecasting models. Such models are more difficult to validate than their single-period equivalents, because consecutive observations are subject to common shocks that undermine i.i.d. The paper examines various solutions to this problem, and proposes a new solution based on the application of standard tests to a resample that is constructed to be i.i.d. It suggests that this solution is superior to alternatives, and presents results indicating that tests based on the i.i.d. resample approach have good power.,,Copyright © 2007 John Wiley & Sons, Ltd. [source]