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PubMed1993

Misinformation and warnings in eyewitness testimony: a new testing procedure to differentiate explanations.

Although psychologists agree that the presentation of misleading post-event information often results in errant recollections, there is disagreement about the explanation as to why this occurs. Some (cf. Loftus, Donders, Hoffman, & Schooler, 1989) believe this misinformation alters the memory trace created by the original information, whereas others (cf. McCloskey & Zaragoza, 1985) have argued that the data do not necessitate this explanation. An experiment, designed to differentiate the various explanations, was conducted. Its critical elements were: (1) a condition with a specific warning presented immediately after the misleading information; and (2) a ranking procedure used at testing. The results suggest multiple traces may exist for a limited period, but not indefinitely.

Chi-Square Distribution↗
PubMed1994

Why are there sometimes concreteness effects in memory for prose?

Four experiments explored on-line encoding strategies and memory for high imagery and low imagery texts. Results consistently indicated that concreteness effects in memory for text depend on how materials are presented in several different respects. Most importantly, the experiments clarified apparently contradictory results of previous studies by indicating that concreteness effects generally do not occur in memory for prose when imageability is manipulated between-subjects, and that their occurrence when imageability is manipulated within-subjects depends on the order occurrence when imageability is manipulated within-subjects depends on the order of presentation. In addition, moving window analyses of text processing strategies indicated that differential strategies observed in previous studies when subjects listened to high vs low imagery text do not generalize to reading of the same materials. Potential explanations for the pattern of results are evaluated, and implications for theories of mental imagery and memory are considered.

Analysis of Variance↗
PubMed1994

Assessment of long-term verbal memory in children.

This study was designed to evaluate the use of a Paired Associate Learning Test (PALT) and a Story Recall test with children aged from 8 to 12 years. 46 normal control children and 19 children of low ability were given the PALT from the Wechsler Memory Scale, and a story recall task, based on Wechsler's Logical Memory subtest, but using stories designed to be suitable for children. Performance on PALT approached ceiling levels for the control children. Both PALT and story recall were more strongly correlated with measures of verbal ability than with digit span. Reliable measures of immediate story recall can be obtained using two or three stories. Many children who are unable to recall a story after a 45 minute delay show dramatic improvement when given a single cue, and it is argued that cued delayed recall gives a better index of long-term memory than uncued recall. Correlations between immediate recall and cued delayed recall are high, and the data presented here may be used to compute a forgetting score which takes into account the level of immediate recall. In the sample seen here, rate of forgetting was remarkably constant across individuals, in both normal and low ability individuals. It is concluded that memory deficits affecting rate of forgetting are rare, but that the test materials described here could be useful for identifying such disorders in children with neurological impairments.

Case-Control Studies↗
PubMed2004

Methodological problems related to alcohol research among Turks and Moroccans living in the Netherlands: findings from semi-structured interviews.

OBJECTIVES: To identify factors related to alcohol use among Turks and Moroccans living in the Netherlands. Furthermore, to reveal methodological problems related to research among Turks and Moroccans in general and to alcohol research among these groups in particular. DESIGN: Individual face-to-face interviews were carried out with Dutch researchers (n = 9), Turkish and Moroccan (health) practitioners working in the field with Turks (n = 4) or Moroccans (n = 2), and members of the target population with a Turkish (n = 3) or a Moroccan background (n = 2). Furthermore, focus-group interviews were held with Turkish women (n = 4), Turkish men (n = 3), Moroccan women (n = 4) and Moroccan men (n = 3) working as health professionals. RESULTS: Alcohol use seems prevalent particularly among second-generation Turks and Moroccans and is related to: upbringing, influence of peer groups, integration and the degree in which Islamic rules are practised. Written questionnaires seem more appropriate for second-generation Turks and Moroccans, because they have fewer language problems and are more familiar with Western bureaucratic society. However, both generations may prefer face-to-face interviews since both groups fear that 'written' answers about the sensitive subject 'alcohol use' may somehow become known among community members. Similarly, an interviewer with a Dutch background may elicit more reliable answers about alcohol use than an interviewer with a Turkish or Moroccan background. CONCLUSION: In alcohol research special attention should be paid to second-generation Turks and Moroccans. Although it is probably easier to conduct alcohol studies in this group than in first-generation Turks and Moroccans, quantitative research is needed to test the hypothesis that written questionnaires elicit more reliable answers about alcohol use than face-to-face interviews. Furthermore, the influence of ethnic matching on response and data quality should be tested further.

Alcohol Drinking↗
PubMed2004

Conditional bias of point estimates following a group sequential test.

Repeated significance testing in a sequential experiment not only increases the overall type I error rate of the false positive conclusion but also causes biases in estimating the unknown parameter. In general, the test statistics in a sequential trial can be properly approximated by a Brownian motion with a drift parameter at interim looks. The unadjusted maximum likelihood estimator can be potentially very biased due to the possible early stopping rule at any interim. In this paper, we investigate the conditional and marginal biases with focus on the conditional one upon the stopping time in estimating the Brownian motion drift parameter. It is found that the conditional bias may be very serious for existing point estimation methods, even if the unconditional bias is satisfactory. New conditional estimators are thus proposed, which can significantly reduce the conditional bias from unconditional estimators. The results of Monte-Carlo studies show that the proposed estimators can provide a much smaller conditional bias and MSE than the naive MLE and a Whitebead's bias reduced estimator.

Effect Modifier, Epidemiologic↗
PubMed2005

Multilevel analysis of infectious diseases.

Traditional study designs, such as individual-level studies and ecological studies, are unable to simultaneously examine the effects of individual-level and group-level factors on risk of disease. Multilevel analysis overcomes this limitation by allowing the simultaneous investigation of factors defined at multiple levels. Areas in which multilevel modeling can be applied to sexually transmitted infection (STI) research include examining how both group-level and individual-level factors are related to individual-level STI outcomes, assessing interactions between individual-level and group-level constructs, and exploring how factors at multiple levels contribute to group-to-group differences in rates of disease. In this article, we review the fundamentals of multilevel modeling, the applications of multilevel models for the examination of STIs, and the key challenges associated with using multilevel modeling for infectious-disease research.

Data Interpretation, Statistical↗
PubMed1998

Experience with two validation methods in a prevalence survey on nosocomial infections.

OBJECTIVE: To determine whether an investigator effect remained on the first German study on the prevalence of nosocomial infections Nosokomiale Infektionen in Deutschland Erfassung und Prävention (NIDEP), despite extensive validation efforts. DESIGN: Two validation methods were applied: bedside validation and validation by case studies. In both cases, the results of the four investigators were compared with the diagnosis of gold standard observers. SETTING: Validation measures were applied before, intermittently, during, and at the end of the surveillance period in 72 acute-care hospitals with 14,966 patients. RESULTS: The overall sensitivity in the bedside-validation periods was 89.0%; the overall specificity was 99.5%. For validation by case studies, overall sensitivity was 95.6%, and overall specificity was 92.8%. At the end of the surveillance, a remarkable investigator effect was found. CONCLUSION: Despite validation results that were assessed as satisfactory, based on available literature, an investigator effect was observed. This underlines the need for data validation and the formulation of recommendations for data validation. Clarification of the Centers for Disease Control and Prevention criteria for pneumonia and primary bloodstream infection and the inclusion of some diagnostic test results may reduce or prevent an investigator effect in future studies.

Bias↗
PubMed2002

Dose-effect modifying factors in radiation protection--a 1967 National Commission on Radiation Protection document revisited.

In 1967 Subcommittee M-4 of the National Commission on Radiation Protection proposed a system for evaluating, summing and reporting occupational exposures. It appears that some 30 years later these concepts could be implemented in a system of radiation protection based on Katz's cellular track structure model, which is able to quantify and predict the response of systems relevant to radiation protection, such as survival or oncogenic transformations in cell cultures, enzymes, bacteria or whole organisms. As a consequence of this approach, an m-power-law (with m ranging between 2 and 3.5) dependence of effect, or radiation risk, after doses of standard Co-60 radiation, would follow.

Effect Modifier, Epidemiologic↗
PubMed2004

n-of-1 randomized controlled trials: an opportunity for complementary and alternative medicine evaluation.

Complementary and alternative medicine (CAM) practice has traditionally relied on expert opinion and case examples to evaluate the outcome of a particular therapeutic treatment. Such trials are subject to bias, leading to the formation of erroneous conclusions about the effectiveness of most treatments. This paper reviews the feasibility of n-of-1 trials to better evaluate the clinical and statistical significance of CAM therapies. In particular: (1) problems arising from the use of standard therapeutic trials; (2) the n-of-1 trial and data analysis; (3) clinical use and advantages of the n-of-1 trial in conventional medicine; (4) potential clinical uses of the n-of-1 trial in CAM; (5) preliminary guidelines for the use of the n-of-1 trial in CAM; (6) constraints on the use of the n-of-1 trial in CAM; and (7) ethical issues in the conduct of the n-of-1 trial.

Bias↗
PubMed2002

Do interviewers' health beliefs and habits modify responses to sensitive questions? A study using data Collected from pregnant women by means of computer-assisted telephone interviews.

If interviewers' personal habits or attitudes influence respondents' answers to given questions, this may lead to bias, which should be taken into consideration when analyzing data. The authors examined a potential interviewer effect in a study of pregnant women in which exposure data were obtained through computer-assisted telephone interviews. The authors compared interviewer characteristics for 34 interviewers with the responses they obtained in 12,910 interviews carried out for the Danish National Birth Cohort Study. Response data on smoking and alcohol consumption in the first trimester of pregnancy were collected during the time period October 1, 1997-February 1, 1999. Overall, the authors found little evidence to suggest that interviewers' personal habits or attitudes toward smoking and alcohol consumption during pregnancy had consequences for the responses they obtained; neither did the interviewers' education, age, or parity correlate with the answers they obtained. In these data gathered through computer-assisted telephone interviews, interviewer effects arising from variations in interviewers' health beliefs and personal habits were found to be negligible. Thorough training of the interviewers and continuous supervision may have contributed to this finding.

Adult↗
PubMed2006

The effect of ozone and PM10 on hospital admissions for pneumonia and chronic obstructive pulmonary disease: a national multicity study.

A case-crossover study was conducted in 36 US cities to evaluate the effect of ozone and particulate matter with an aerodynamic diameter of < or =10 microm (PM10) on respiratory hospital admissions and to identify which city characteristics may explain the heterogeneity in risk estimates. Respiratory hospital admissions and air pollution data were obtained for 1986-1999. In a meta-analysis based on the city-specific regression models, several city characteristics were evaluated as effect modifiers. During the warm season, the 2-day cumulative effect of a 5-ppb increase in ozone was a 0.27% (95% confidence interval (CI): 0.08, 0.47) increase in chronic obstructive pulmonary disease admissions and a 0.41% (95% CI: 0.26, 0.57) increase in pneumonia admissions. Similarly, a 10-microg/m(3) increase in PM10 during the warm season resulted in a 1.47% (95% CI: 0.93, 2.01) increase in chronic obstructive pulmonary disease at lag 1 and a 0.84% (95% CI: 0.50, 1.19) increase in pneumonia at lag 0. Percentage of households with central air conditioning reduced the effect of air pollution, and variability of summer apparent temperature reduced the effect of ozone on chronic obstructive pulmonary disease. The study confirmed, in a large sample of cities, that exposure to ozone and PM10 is associated with respiratory hospital admissions and provided evidence that the effect of air pollution is modified by certain city characteristics.

Aged↗
PubMed2006

Individual-level modifiers of the effects of particulate matter on daily mortality.

Consistent evidence has shown a positive association between particulate matter with an aerodiameter of less than or equal to 10 mum (PM(10)) and daily mortality. Less is known about the modification of this association by factors measured at the individual level. The authors examined this question in a case-crossover study of 20 US cities. Mortality events (1.9 million) were obtained for nonaccidental, respiratory, heart disease, and stroke mortality between 1989 and 2000. PM(10) concentrations were obtained from the US Environmental Protection Agency. The authors examined the modification of the PM(10)-mortality association by sociodemographics, location of death, season, and secondary diagnoses. They found different patterns of PM(10)-mortality associations by gender and age but no differences by race. The level of education was inversely related to the risk of mortality associated with PM(10). PM(10)-related, out-of-hospital deaths were more likely than were in-hospital deaths, as were those occurring during spring/fall versus summer/winter. A secondary diagnosis of diabetes modified the effect of PM(10) for respiratory and stroke mortality. Pneumonia was a positive effect modifier for deaths from all causes and stroke, while secondary stroke modified the effects for all-cause and respiratory deaths. The findings suggest that more attention must be paid to population characteristics to identify greater likelihood of exposures and susceptibility and, as a result, to improve policy making for air pollution standards.

Aged↗
PubMed2005

The effect of data collection mode and ethnicity of interviewer on response rates and self-reported alcohol use among Turks and Moroccans in the Netherlands: an experimental study.

AIMS: To test the effects of data collection mode and ethnicity of interviewers on response rates and self-reported alcohol use among second-generation Turks and Moroccans in Rotterdam, The Netherlands. METHODS: Two hundred and sixty-nine Turks and 271 Moroccans were interviewed face-to-face, and 475 Turks and 482 Moroccans received a mailed questionnaire. Half of the Turks and Moroccans randomly allocated to the interview mode were ethnically matched to the interviewer; the remainder were allocated to a Dutch interviewer. RESULTS: Turks and Moroccans more often responded to a face-to-face interview than to a mailed questionnaire. No effect of ethnicity of interviewer on response rates was demonstrated. With respect to the effects on alcohol reports, Turks and Moroccans tended to report a higher alcohol use in the mailed survey than in the face-to-face interview. They reported significantly more often excessive drinking in the mail survey than in the face-to-face interviews. Ethnicity of the interviewer resulted in Turks and Moroccans reporting a higher prevalence of alcohol use during the previous 6 months when interviewed by a Dutch interviewer compared with an ethnically matched interviewer. CONCLUSIONS: Among second-generation Turks and Moroccans, mail surveys seem most suitable to measure mean and excessive alcohol use. However, interviews held by Dutch interviewers seem to be the most appropriate method to study the prevalence of alcohol use during the previous 6 months.

Adolescent↗
PubMed1991

Extrapolating from toxicity data to occupational exposure limits: some considerations.

This paper evaluates procedures relevant to extrapolating from toxicity data in man and animals to Occupational Exposure Limits. It examines effects at or around the "No Observed Adverse Effect Level' (NOAEL) and the magnitude of safety factors which can be applied in developing occupational exposure limits for non-stochastic effects. The relationship between incidence of stochastic effect and occupational exposure limit is also discussed.

Clinical Protocols↗
PubMed2005

RNA secondary structural alignment with conditional random fields.

MOTIVATION: The computational identification of non-coding RNA regions on the genome is currently receiving much attention. However, it is essentially harder than gene-finding problems for protein-coding regions because non-coding RNA sequences do not have strong statistical signals. Since comparative sequence analysis is effective for non-coding RNA detection, efficient computational methods are expected for structural alignment of RNA sequences. Several methods have been proposed to accomplish the structural alignment tasks for RNA sequences, and we found that one of the most important points is to estimate an accurate score matrix for calculating structural alignments. RESULTS: We propose a novel approach for RNA structural alignment based on conditional random fields (CRFs). Our approach has some specific features compared with previous methods in the sense that the parameters for structural alignment are estimated such that the model can most probably discriminate between correct alignments and incorrect alignments, and has the generalization ability so that a satisfiable score matrix can be obtained even with a small number of sample data without overfitting. Experimental results clearly show that the parameter estimation with CRFs can outperform all the other existing methods for structural alignments of RNA sequences. Furthermore, structural alignment search based on CRFs is more accurate for predicting non-coding RNA regions than the other scoring methods. These experimental results strongly support our discriminative method employing CRFs to estimate the score matrix parameters. AVAILABILITY: The program which is implemented in C++ is available at http://phmmts.dna.bio.keio.ac.jp/ under the GNU public license.

Base Sequence↗
PubMed1996

Methodology of morbidity and treatment data collection in general practice in Australia: a comparison of two methods.

OBJECTIVES: To compare two methods of data collection of patient-practitioner encounter data in general practice: from medical records consultation notes and from data recorded on encounter forms. METHOD: Data were collected from two sources: (i) Medical Records Study: a study of the efficacy of an intervention designed to improve the quality of medical records provided details of 3107 patient encounters with 163 general practitioners (GPs) which had been photocopied from medical records; and (ii) Australian Morbidity and Treatment Survey (AMTS): from a national sample of 495 GPs and over 100,000 patient encounters, data from 47 GPs in the same geographical area as those in the Medical Records Study provided encounter forms for 10,392 patient encounters including details about patient demographics, reason for encounter, management, treatment, tests and investigations, admissions, referrals and planned follow-up. The International Classification of Primary Care (ICPC) was used to code reasons for encounter and problems managed. Drugs were classified according to an in-house classification by generic name and broad drug group. RESULTS: Patient details and all items of clinical information were recorded less frequently or were more often illegible in medical records than on encounter forms. There was a higher rate of management of problems classified as general or non-specific in the medical records. A lower prescribing rate for drugs acting on the cardiovascular system was recorded in the medical records, but higher rates were found for antibiotics, drugs acting on the immune system and miscellaneous drugs. Coding of all data was more reliable both between and within coders using the data from the encounter forms compared to the medical records. CONCLUSION: General practice data obtained from encounter forms are more comprehensive and are coded more reliably than those drawn from medical records.

Adolescent↗