PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Measurement Fidelity”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4Linked to original sources
PubMed2001

Wave-front measurement errors from restricted concentric subdomains.

In interferometry and optical testing, system wave-front measurements that are analyzed on a restricted subdomain of the full pupil can include predictable systematic errors. In nearly all cases, the measured rms wave-front error and the magnitudes of the individual aberration polynomial coefficients underestimate the wave-front error magnitudes present in the full-pupil domain. We present an analytic method to determine the relationships between the coefficients of aberration polynomials defined on the full-pupil domain and those defined on a restricted concentric subdomain. In this way, systematic wave-front measurement errors introduced by subregion selection are investigated. Using vector and matrix representations for the wave-front aberration coefficients, we generalize the method to the study of arbitrary input wave fronts and subdomain sizes. While wave-front measurements on a restricted subdomain are insufficient for predicting the wave front of the full-pupil domain, studying the relationship between known full-pupil wave fronts and subdomain wave fronts allows us to set subdomain size limits for arbitrary measurement fidelity.

Journal Article↗
PubMed1994

Frequency (pitch) and duration pattern tests.

Compact disc versions of the frequency (pitch) and duration pattern tests are reported. Results are similar to previous reports on these tests using taped materials. Mean performance of normal-hearing young adults for both pattern perception tests was approximately 90 percent. There was no effect of the two presentation levels used in this study. The compact disc version of these tests provides a high-fidelity measure of auditory pattern identification that can be administered easily.

Acoustic Stimulation↗
PubMed2006

Fidelity and coherence measures from interference.

By utilizing single particle interferometry, the fidelity or coherence of a pair of quantum states is identified with their capacity for interference. We consider processes acting on the internal degree of freedom (e.g., spin or polarization) of the interfering particle, preparing it in states rho_{A} or rho_{B} in the respective path of the interferometer. The maximal visibility depends on the choice of interferometer, as well as the locality or nonlocality of the preparations, but otherwise depends only on the states rho_{A} and rho_{B} and not the individual preparation processes themselves. This allows us to define interferometric measures which probe locality and correlation properties of spatially or temporally separated processes, and can be used to differentiate between processes that cannot be distinguished by direct process tomography using only the internal state of the particle.

Journal Article↗
PubMed2002

Beyond components: using fidelity scales to measure and assure choice in program implementation and quality assurance.

Fidelity scales have become an accepted part of intervention research. Initially, fidelity scales focused on critical components of an intervention. In this paper we argue that the next generation of fidelity scales should include key process variables such as choice. Since choice is an essential element in all empowerment and recovery driven intervention models, a fidelity scale for an enhanced version of the Individual Placement and Support (IPS) supported employment model that incorporates choice as a fundamental component was developed as part of a SAMHSA community action grant. The process for developing the choice component and the dimensions measured are also described.

Choice Behavior↗
PubMed2003

A review of research on fidelity of implementation: implications for drug abuse prevention in school settings.

To help inform drug abuse prevention research in school settings about the issues surrounding implementation, we conducted a review of the fidelity of implementation research literature spanning a 25-year period. Fidelity has been measured in five ways: (1) adherence, (2) dose, (3) quality of program delivery, (4) participant responsiveness and (5) program differentiation. Definitions and measures of fidelity were found not to be consistent across studies, and new definitions are proposed. While there has been limited research on fidelity of implementation in the social sciences, research in drug abuse prevention provides evidence that poor implementation is likely to result in a loss of program effectiveness. Studies indicate that most teachers do not cover everything in a curriculum, they are likely to teach less over time and training alone is not sufficient to ensure fidelity of implementation. Key elements of high fidelity include teacher training, program characteristics, teacher characteristics and organizational characteristics. The review concludes with a discussion of the tension between fidelity and reinvention/adaptation, and ways of resolving this tension. Recommendations are made for developing a consistent methodology for measuring and analyzing fidelity of implementation. Further, researchers and providers should collaborate to develop ways of introducing flexibility into prevention programs.

Curriculum↗
PubMed2003

Fidelity of select restriction endonucleases in determining microbial diversity by terminal-restriction fragment length polymorphism.

An evaluation of 18 DNA restriction endonucleases for use in terminal-restriction fragment length polymorphism (T-RFLP) analysis was performed by using richness and density indices in conjunction with computer simulations for 4,603 bacterial small-subunit rRNA gene sequences. T-RFLP analysis has become a commonly used method for screening environmental samples for precursory identification and community comparison studies due to its precision and high-throughput capability. The accuracy of T-RFLP analysis for describing a community has not yet been thoroughly evaluated. In this study, we attempted to classify restriction endonucleases based upon the ability to resolve unique terminal-restriction fragments (T-RFs) or operational taxonomic units (OTUs) from a database of gene sequences. Furthermore, we assessed the predictive accuracy of T-RFLP at fixed values of community richness (n = 1, 5, 10, 50, and 100). Classification of restriction endonuclease fidelity was performed by measuring richness and density for the entire database of T-RFs. Further analysis of T-RFLP accuracy for determining richness was performed by iterative, random sampling from the derived database of T-RFs. It became apparent that two constraints were influential for measuring the fidelity of a given restriction endonuclease: (i) the ability to resolve unique sequence variants and (ii) the number of unique T-RFs that fell within a measurable size range. The latter constraint was found to be more significant for estimating restriction endonuclease fidelity. Of the 18 restriction endonucleases examined, BstUI, DdeI, Sau96I, and MspI had the highest frequency of resolving single populations in model communities. All restriction endonucleases used in this study detected < or =70% of the OTUs at richness values greater than 50 OTUs per modeled community. Based on the results of our in silico experiments, the most efficacious uses of T-RFLP for microbial diversity studies are those that address situations where there is low to intermediate species richness (e.g., colonization, early successional stages, biofilm formation).

Bacteria↗
PubMed2006

The impact of therapeutic case management on participation in adolescent substance abuse treatment.

Establishing the efficacy of case management in substance abuse treatment has been confounded by the lack of attention given to assessing the fidelity of case management implementation. The current study measured the fidelity of case management implementation and used fidelity information to examine the impact of therapeutic case management on attrition in an adolescent, outpatient, group, substance abuse treatment program. Ninety adolescent women enrolled in substance abuse treatment were randomly assigned to receive or to not receive case management. Treatment fidelity was measured using the Case Management Quality Inventory. Cox regression analyses revealed that higher fidelity of case management implementation predicted a decreased risk of dropping out of the substance abuse treatment program (RR = -11.21, p < 0.02). Higher proportions of total case management time spent on case management core functions predicted a decreased risk of dropping out of treatment (RR = 4.32, p < 0.03). This study confirms that programs need to first demonstrate that the case management model has been implemented faithfully before its efficacy in reducing attrition in the substance abuse treatment program can be fairly evaluated. It also suggests that core case management functions may have a greater influence on attrition in substance abuse treatment than does intensity.

Adolescent↗
PubMed1990

DNA polymerase alpha from HeLa cells synthesizes DNA with high fidelity in a reconstituted replication system.

To determine the contribution that DNA polymerase alpha makes to the overall DNA replication fidelity in mammalian systems, we measured the fidelity of replication of the SV40-based shuttle vector, pZ189, in a reconstituted in vitro DNA replication system which contained purified HeLa DNA polymerase alpha (in addition to single-stranded DNA binding protein, topoisomerase II, DNA ligase, 5'----3' exonuclease, ribonuclease H, and SV40 T-antigen). We found that DNA polymerase alpha is highly accurate when carrying out bidirectional replication in this system. This high fidelity of replication by DNA polymerase alpha in the reconstituted replication system contrasts with a relatively low fidelity of gap-filling DNA synthesis on the same target gene by purified HeLa cell DNA polymerase alpha in the absence of other replication factors. The fidelity of DNA replication by DNA polymerase alpha, although relatively high in the reconstituted system, is about 4-fold lower than DNA replication in a crude HeLa cell extract which contains additional replication factors including DNA polymerase delta. These results demonstrate that DNA polymerase alpha has the capacity to replicate DNA with high fidelity when carrying out semiconservative DNA replication in a minimal reconstituted replication system, but additional cellular factors not present in the reconstituted system may contribute to the higher replication fidelity of the crude system.

Cell-Free System↗
PubMed1983

Diastolic function in hypertrophic cardiomyopathy: effects of propranolol and verapamil on diastolic stiffness.

In patients with hypertrophic cardiomyopathy (HCM), impaired left ventricular (LV) relaxation and diastolic filling have been reported. Therefore, we determined LV diastolic stiffness in nine patients with HCM before and 10 to 15 min after 0.15 mg/kg propranolol i.v. (group 1) and in six patients with HCM before and 10 to 15 min after 0.1 mg/kg verapamil i.v. (group 2). Simultaneous LV cineangiography and high-fidelity pressure measurements were performed in group 1 and simultaneous M-mode echocardiography and high-fidelity pressure measurements in group 2. Passive LV chamber stiffness was determined in group 1 from the diastolic pressure-volume data using an exponential three-parameter model: P = ae beta V + C, where P = pressure, alpha = intercept, beta = constant of chamber stiffness, V = volume and C = baseline pressure. Passive LV myocardial stiffness was estimated in group 2 from the diastolic stress-strain data using a viscoelastic model: sigma = alpha' (e beta' epsilon -1) + eta epsilon, where sigma = meridional wall stress, alpha = intercept, beta' = constant of myocardial stiffness, epsilon = midwall strain, eta = constant of myocardial viscosity and epsilon = strain rate. LV relaxation was assessed from the time constant of LV pressure decay (T) by plotting LV pressure versus negative dP/dt. LV diastolic filling was evaluated from peak and mean LV filling rate in group 1 and from peak and mean midwall lengthening rate in group 2. LV chamber and myocardial stiffness, respectively, remained unchanged before and after administration of propranolol (beta = 0.054 and 0.047) and verapamil (beta' = 14.8 and 12.6); however, the time constant of LV pressure decay T increased significantly in group 1 from 45 to 66 ms (P less than 0.05) and decreased significantly in group 2 from 53 to 43 ms (P less than 0.05). Parallel to the changes in LV isovolumic relaxation, mean LV diastolic filling rate decreased significantly in group 1 from 257 to 196 ml m-2 s-1 (P less than 0.025) and mean LV midwall lengthening rate increased significantly in group 2 from 2.37 to 4.31 cm/sec (P less than 0.05). It is concluded that LV diastolic stiffness remains unchanged in patients with HCM after propranolol and verapamil. LV relaxation and mean diastolic filling, however, are impaired in patients with HCM following propranolol but are improved after verapamil. Thus, the beneficial effect of verapamil on diastolic mechanics is related to improved relaxation and diastolic filling rather than to changes in LV diastolic stiffness.

Cardiomyopathy, Hypertrophic↗
PubMed2000

[A study of the guideline of case management for persons with mental disorders analyzed with fidelity index. The conditions of effective implementation].

OBJECTIVE: The present study examines the condition of effective case management based on the guideline of case management for persons with mental disorders. METHODS: A total of 295 clients were admitted to a case management trial for about 2 months. A fidelity index of program implementation and outcome measures of case management were developed. The relationship between implementation of critical program components measured by fidelity index, and outcome was analyzed. RESULTS: Fidelity Index was significantly correlated with outcome measures of clients, staffs and the care system. Effective but not-easily-feasible elements of program were having case-conference, application, of informal support and development of services. CONCLUSION: It is necessary to facilitate application of informal support with liaison with public health nurses, to standardize case-conference and to place development of care services in the core of programs for ensuring effective implementation of case management for persons with mental disorders in Japan.

Adult↗
PubMed1987

Echocardiographic left ventricular mass and function in the hypertensive baboon.

Nonhuman primates with chronic systemic hypertension provide an ideal model for studying structural and functional alterations associated with compensatory cardiac hypertrophy. Since noninvasive techniques are useful for the longitudinal evaluation of these animals, we sought to critically asses the M-mode echocardiographic estimation of left ventricular mass in the baboon and to characterize estimates of left ventricular size and function in baboons with chronic renal hypertension. In 23 baboons (12 normotensive, 11 chronic hypertensive), M-mode echocardiography-determined left ventricular mass was 73 +/- 13 (SE) g as compared with the necropsy weight of 69 +/- 11 g (p = NS), and the correlation was excellent (r = 0.94). When 30 chronically hypertensive baboons being observed longitudinally were compared with 10 normotensive control animals studied under identical conditions, several differences were noted in measures derived from echocardiography and high fidelity pressure measurements. Left ventricular systolic pressure was considerably higher in the hypertensive baboons (113 +/- 23 vs 90 +/- 11 mm Hg; p less than 0.001), as was left ventricular mass (148 +/- 60 vs 103 +/- 38 g; p less than 0.03). However, since the ratio of posterior wall thickness to cavity dimension was larger in the hypertensive baboons (0.52 +/- 0.17 vs 0.43 +/- 0.07; p less than 0.05), this concentric hypertrophy maintained values for left ventricular meridional stress at the same level as in the control animals. Despite matched heart rate and left ventricular stress, the rates of change in left ventricular dimensions and wall thickness in systole and diastole were all approximately 25% less in the hypertrophied baboons.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Fidelity of a human cell DNA replication complex.

We have measured the fidelity of bidirectional, semiconservative DNA synthesis by a human DNA replication complex in vitro. Replication was performed by extracts of HeLa cells in the presence of simian virus 40 (SV40) large tumor antigen by using a double-stranded phage M13mp2 DNA template containing the SV40 origin of replication and either of two different target sequences for scoring mutations in the lacZ alpha-complementation gene, which encodes the alpha region (specifying the amino-terminal portion) of beta-galactosidase. Replicative synthesis was substantially more accurate than synthesis by the human DNA polymerase alpha-DNA primase complex purified from HeLa cell extracts by immunoaffinity chromatography, suggesting that additional factors or activities in the extract may increase fidelity during bidirectional replication. However, by using a sensitive opal codon reversion assay, single-base substitution errors were readily detected in the replication products at frequencies significantly higher than estimated spontaneous mutation rates in vivo. These data suggest that additional fidelity factors may be present during chromosomal replication in vivo and/or that the fidelity of replication alone does not account for the low spontaneous mutation rates in eukaryotes.

Antigens, Polyomavirus Transforming↗
PubMedDate not supplied

A method for describing and evaluating naturopathic whole practice.

CONTEXT: Even though complementary and alternative medicine (CAM) is generally practiced as distinct systems of medicine, almost all CAM research has focused on single therapies. In order to more adequately evaluate the effectiveness of these medical systems, studies that evaluate the outcome of intact whole systems are needed. One challenge lies in defining the whole medical system (and any medical system it is compared to) in a way that ensures treatment fidelity. OBJECTIVE: This paper presents a proposed method to measure treatment fidelity (treatment criteria) in studies of the naturopathic medical system. DESIGN: Illustrative example of the theory-based development and post-hoc "testing" of treatment criteria against an existing database of actual treatments prescribed by a random sample of naturopathic physicians. MAIN OUTCOME MEASURES: Treatment criteria for 3 conditions--menopausal symptoms, bowel dysfunction, and fatigue/fibromyalgia--and their comparison to actual treatments prescribed. RESULTS: A set of meaningful, measurable treatment criteria based on the naturopathic practice principles were defined that could have generated the majority (82%-93%) of treatment prescriptions given at visits for these conditions. Several of the treatment criteria components are common across the 3 conditions studied, and might be appropriate for all visits to doctors of naturopathy (NDs). Others are specific to each condition. In addition to ensuring model validity, these criteria help identify critical components of care, enable study replication, provide a measure of quality of care, and are one step toward allowing CAM to be studied as it is generally practiced-as distinct systems of medicine. SETTING: Work was performed at Bastyr University and the University of Arizona.

Clinical Protocols↗
PubMed1977

Infidelity of DNA synthesis as related to mutagenesis and carcinogenesis.

An assay system has been developed for measuring the fidelity of DNA synthesis in vitro by using synthetic polynucleotide templates and purified DNA polymerases. Nearest-neighbor analysis of the synthesized product indicates that noncomplementary nucleotides are incorporated as single base substitutions. The accuracy of DNA synthesis can be decreased by (1) prior alkylation of the template, (2) increasing the relative concentration of incorrect nucleotides, and (3) addition of specific metal salts to the reaction mixture. As an initial evaluation of the utility of this system, the effects of 31 metal salts on the fidelity of DNA synthesis have been determined. The results indicate that potential metal mutagens and/or carcinogens may be detected by measuring alterations in the fidelity of DNA synthesis.

Avian Myeloblastosis Virus↗
PubMed2005

Information theory-based algorithm for in silico prediction of PCR products with whole genomic sequences as templates.

BACKGROUND: A new algorithm for assessing similarity between primer and template has been developed based on the hypothesis that annealing of primer to template is an information transfer process. RESULTS: Primer sequence is converted to a vector of the full potential hydrogen numbers (3 for G or C, 2 for A or T), while template sequence is converted to a vector of the actual hydrogen bond numbers formed after primer annealing. The former is considered as source information and the latter destination information. An information coefficient is calculated as a measure for fidelity of this information transfer process and thus a measure of similarity between primer and potential annealing site on template. CONCLUSION: Successful prediction of PCR products from whole genomic sequences with a computer program based on the algorithm demonstrated the potential of this new algorithm in areas like in silico PCR and gene finding.

Algorithms↗
PubMed2006

Relations between program and system variables and fidelity to the wraparound process for children and families.

OBJECTIVE: Past research and experience have indicated that characteristics of organizations and service systems influence the quality of mental health services delivery. The study aimed to illuminate such associations by examining the relationship between a set of program- and system-level variables and fidelity to the wraparound model for children and families. METHODS: A measure of fidelity to the wraparound process for children and families (the Wraparound Fidelity Index) was administered to families receiving services in eight mental health agencies across the United States. Program administrators at each agency also completed by telephone a standardized interview for assessing program and system conditions hypothesized to influence quality of implementation (Program Administrator version of the Wraparound Fidelity Index). Regression analyses were used to assess the relationship between program and system variables and fidelity. RESULTS: Results of interviews with program administrators revealed substantial variation across programs in the number and type of program and system supports for wraparound implementation. Regression analyses found a significant association between the number of organizational and system supports and Wraparound Fidelity Index scores. CONCLUSIONS: Results support the hypothesized relationship between program and system conditions and the quality of service delivery. Results also highlight the importance of engineering the system and organizational context (maintaining low caseload sizes, establishing interagency partnerships, and implementing accountability mechanisms) in order to provide a solid foundation for high-quality wraparound to children and families.

Child↗