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Gamma-ray spectrometry data collection and reduction by simple computing systems.

The review summarizes the present state of the involvement of relatively small computing devices in the collection and processing of gamma-ray spectrum data. An economic and utilitarian point of view has been chosen with regard to data collection in order to arrive at practically valuable conclusions in terms of feasibility of possible configurations with respect to their eventual application. A unified point of view has been adopted with regard to data processing by developing an information theoretical approach on a more or less intuitive level in an attempt to remove the largest part of the virtual disparity between the several processing methods described in the literature. A synoptical introduction to the most important mathematical methods has been incorporated, together with a detailed theoretical description of the concept gamma-ray spectrum. In accordance with modern requirements, the discussions are mainly oriented towards high-resolution semiconductor detector-type spectra. The critical evaluation of the processing methods reviewed is done with respect to a set of predefined criteria. Smoothing, peak detection, peak intensity determination, overlapping peak resolving and detection and upper limits are discussed in great detail. A preferred spectrum analysis method combining powerful data reduction properties with extreme simplicity and speed of operation is suggested. The general discussion is heavily oriented towards activation analysis application, but other disciplines making use of gamma-ray spectrometry will find the material presented equally useful. Final conclusions are given pointing to future developments and shifting their centre of gravity towards improving the quality of the measurements rather than expanding the use of tedious and sophisticated mathematical techniques requiring the limits of available computational power.

Activation Analysis

Use of a viewdata system to collect data from a multicentre clinical trial in anaesthesia.

The interactive electronic information storage and transmission system PRESTEL was assessed as a method of recording and collecting patient record forms from a multicentre trial in anaesthesia. PRESTEL terminals were provided in anaesthetic centres around Britain and all data handled by this public viewdata service, which connects users by telephone to a central computer. The trial was of a new analgesic supplement, alfentanil, and confirmed more rapid recovery of patients as compared with that after traditional anaesthesia with halothane. Advantages of the system were manifold and included reducing the need for the trial monitor to visit the trialist, an electronic "mailbox," confidentiality, and the ability immediately to identify violations of study protocol. No participant found the system too difficult to use, though the small keyboard was a source of complaint. Despite the initial cost of the system its utility vastly outweighs traditional methods of data collection.

Adjuvants, Anesthesia

Reporting errors in time-to-pregnancy data collected with a short questionnaire. Impact on power and estimation of fecundability ratios.

Few tools exist in reproductive epidemiology for studying adverse effects on fertility. Data on time to pregnancy (the number of menstrual cycles required to conceive) can be used to estimate fecundability ratios, a sensitive endpoint for identifying factors associated with reduced fertility. Time-to-pregnancy data can be collected in detailed interviews. The accuracy of data collected on brief, self-administered questionnaires is not known. In a study of occupational exposures to dental assistants conducted in 1987-1988, 523 women provided time-to-pregnancy data both on a short, mailed questionnaire and in a detailed telephone interview. The correlation between the two measures was 0.82. Assuming that the detailed data were accurate, reporting errors in data from the short form were distributed nondifferentially with respect to most covariates of interest in fecundability analyses. Simulation studies were conducted to estimate bias and loss of power from the misclassification. Bias was toward the null. Substantial power was lost in detecting weak exposures. However, exposures that reduce fecundability by 50 percent (equivalent to adding about three cycles to the median time to pregnancy) could still be detected with 80 percent power in samples of about 100 women (half of them exposed to a possible toxin). The authors conclude that time-to-pregnancy data collected with a few self-administered questions can be useful in a variety of epidemiologic studies, including occupational and environmental surveillance programs.

Bias

Problems of case finding and data collection in ambulatory care settings.

The experience gained in a four-year ambulatory care study suggests that major problems of patient care data collection include: 1) Difficulties in obtaining listings of patients by diagnosis/condition that accurately reflect the actual practice experience; 2) Inaccurate coding or identification of the reason for patient visits; and 3) Inability to find the medical record within the system. Data presented here suggest there are certain regularities in completion rates characteristic of research sites and of diagnostic categories.

Adult

Valve data collection: problems and pitfalls.

Since 1981, the Department of Medical Physics and Clinical Engineering at the University of Sheffield has been responsible for the organization, management and data collection associated with the largest multicentre heart valve implant patient follow-up study in the Western world. At the present time, the database comprises information on over 16,000 valve implants, which have been provided by 57 surgeons working at 22 centres in the UK. All this data is available for in-depth statistical analysis. Over 30 individual valve models presently are included in the Study and these can be categorized into five main types: ball, disc, porcine, pericardial and homograft. Analysis includes descriptive statistics as well as valuable information on the various performances of the different valves. Survival and event-free survival graphs are obtained by actuarial methods and individual valve types can be studied in depth in terms of freedom from thromboembolic complications and valve dysfunction. Whilst this approach provides interesting and valuable survival data, it does not take account of the wide variation in prognostic factors which occur within large groups of patients. This latter problem can be addressed by the use of proportional hazards analysis and this paper provides details of this approach and typical results obtained from the use of this method. These include the comparative performances of the major types of valves currently in use in terms of the event-free survival of the patients.

Adolescent

Quality control of dietary data collection in the CARDIA study.

The Coronary Artery Risk Development in (Young) Adults (CARDIA) Study developed and implemented quality control (QC) measures to minimize misclassification associated with dietary data. Manual and automated data inspection were used to monitor quality. Of the 5111 participants who completed a dietary history, 717 (14%) had dietary forms reviewed and 153 (3%) had the interview audiotaped. Results show that for the 717 forms reviewed, the overall form completion error rate was 0.22% and the "critical" error rate (i.e., those errors impacting on nutrient computations) was 0.12%. The proportion of forms free of any type of error increased over time (p less than 0.0001). The discrepancy rate in recording and interviewing methods as estimated from the 153 audiotaped interviews was 0.7%. Inter-interviewer differences were small as indicated by the audiotaped interviews and the proportion of error-free forms completed by interviewers. The results indicate that the dietary data collected in CARDIA were completely and accurately recorded for use in analysis.

Adolescent

International Collaborative Effort (ICE) on birthweight; plurality; and perinatal and infant mortality. I: Methods of data collection and analysis.

This paper describes the collection and analysis of data by a group of international collaborators (International Collaborative Effort on Perinatal and Infant Mortality) interested in comparative studies on birthweight distributions and reproductive outcome. This is the first of a series of reports on the results of these studies. It gives an account of the countries or states involved, and the collection and characteristics of the data. The countries and states included sixteen of the United States, plus England and Wales, Denmark, Bavaria and North Rhine-Westphalia from the Federal Republic of Germany, Israel, Japan, Norway, Scotland, and Sweden. The data comprised birthweight distributions in 500-gram groups for all births and for singletons separately, for livebirths, stillbirths, first week deaths and, where available, late neonatal and infant deaths, from 1970 up to 1985.

Birth Weight

Validity of injury data collected by interview: a study of men born in 1913 and 1923.

An investigation of the validity of anamnestic injury data with special reference to head injuries, was performed, as part of an epidemiological population study of middle aged men. Injury data collected by interview were checked against control data from an emergency department, covering a 7-year period. About 65% of head injuries in the control data set, and 60% of all types of injuries were reported. Injury severity, alcohol intoxication, ambulance transportation and recall period were factors which tended to influence the reporting frequency.

Aged

Data collection in decision-making: a study in general practice.

In a study of simulated consultations with patients suffering from dyspepsia, the amount and nature of information required by 20 general practitioners to make management decisions about these simulated patients were analysed. The number of items of information required to complete all eight cases ranged from 23 to 128 (median 66). Doctors who consulted more rapidly in actual surgeries required less information in the simulations (P less than 0.01). Two-way analysis of variance showed that both cases and doctors independently influenced the number of items of information collected, but that doctors were a more powerful influence (P less than 0.05). The nature of the information collected by doctors varied widely between individuals. There was no correlation between the professional experience of the doctors studied and the amount or nature of data collected; this is at odds with previous studies and requires an alternative explanation.

Data Collection

Accuracy of emergency physician data collection in automobile collisions.

OBJECTIVE: Triage decisions must be based on accurate information with a valid understanding of injury patterns and their sources. Only a data base that includes both medical and collision factors can best provide the breadth of information required to achieve this goal. In the study reported here we assessed the accuracy of automobile collision data collected by emergency physicians compared with Police Accident Reports. DESIGN: Prospective study in which emergency medicine attending physicians completed questionnaires placed near the entrance to the trauma rooms in the emergency department. MATERIALS AND METHODS: During a two-month period the emergency medicine attending physicians obtained data concerning vehicle collision factors for all automobile collisions resulting in major trauma to patients over 18 years of age who were triaged to the Emergency Department at Stanford University Hospital, a level-I trauma center. These data were then compared by one of the investigators with the data contained in Police Accident Reports, which were available for 50 of the 64 patients who met the study eligibility criteria. MEASUREMENTS AND MAIN RESULTS: For each automobile collision, the attending physician was asked to collect the following data: direction of impact; extrication required; ejection; type and use of restraints; deployment of an airbag; type of vehicle; reported severity (minor, moderate, or major) of impact; presence and degree of steering wheel deformation; presence and degree of intrusion into occupant compartment; estimated speed and collision type (i.e., vehicle to vehicle, to fixed object, etc.) Nearly three-fourths (74%) of all cases had at least one discrepancy when compared with the Police Accident Reports, while 46% of these had multiple discrepancies. CONCLUSIONS: When data obtained by emergency physicians are compared with the information in Police Accident Reports, there are notable differences on several collision factors. Triage decisions must be based on accurate information with a valid understanding of injury patterns and their sources. Only a data base that includes both medical and collision factors can best provide the breadth of information required to achieve this goal.

Accidents, Traffic

Community Hospital-based Stroke Programs: North Carolina, Oregon, and New York. I: Goals, objectives, and data collection procedures.

In order to assess the impact of variations in stroke care on outcomes, and to make geographic comparisons, the three Community Hospital-Based Stroke Programs in North Carolina, Oregon, and New York, aggregated their data on 4,132 hospitalized stroke patients. Complete demographic data or "Major Profile" were obtained on 2,390 (57.8%) of the 4,132 stroke patients. This includes those patients on whom informed patient and physician consents were obtained during the hospitalization. Of the major profile patients, 1,490 (62.3%) were followed for periods up to one year, 502 (21.0%) were lost to followup and 398 (16.6%) died within the one year followup period. Incomplete demographic data or "Minor Profile" were observed on 1,742 (42.1%) of the 4,132 patients. Minor profile includes those who died before comprehensive interviews were completed or those for whom informed consent for an interview could not be obtained. Of the minor profile group, 813 (46.7%) died in hospital, and 929 (53.3%) were alive when discharged from the hospital. This paper, which describes the programs, data collection procedures, and study cases, also highlights specific issues on stroke diagnosis, risk factors associated with stroke, and the influence of interventions on stroke outcomes. We conclude that: 1) the merging of data on hospitalized stroke cases from rural and urban hospitals in geographically distinct regions can be used in the study of stroke diagnosis, the use of diagnostic tests, and the effect of interventions on stroke outcomes; and 2) these data are consistent with the hypothesis that part of the national decline in mortality from stroke is due to a decline in stroke severity.

Adult

A quantitative assessment of femoral head activity using 99Tcm -polyphosphate and a computer data collection system.

Abnormal femoral head activity in Legg-Calve-Perthes' disease has been measured using 99Tcm -polyphosphate and a gamma camera/computer data collection system. A reference point on the data matrix, which is unaffected by the diease, is used for deriving comparative uptake ratios in each femoral head. The reference point remains unaltered after surgical procedures or short intervals between follow-up studies. Early abnormality can be measured in both unilateral and bilateral femoral head pathology.

Child

The "key-form" system for data collection in disability evaluation.

A new system for comprehensive disability evaluation has been developed in the framework of our Hospital. This system is based on multidisciplinary evaluation during one day of tests and the summarization of the data collected. The process takes place at the Institute for Functional Evaluation, a joint project of the National Insurance Institute and the Loewenstein Hospital in Israel. The process was designed to provide the basis for the determination of the degree of disability according to the requirements of the General Disability Law. In order to carry out the experimental program a computerized system of recording was created. The method of recording is based upon the "Key-form" where the different systems of the body appear one after the other and next to them the term "normal" or "abnormal". In the case of an abnormal mark, the tester goes on to the next stage which involves completion of a detailed form for that system. The forms are coded for the transfer of information to the computer without intermediary stages and this enables processing of a vast amount of data with relative ease. The system enables compilation of individual profiles and statistical tables and analysis. Theoretical and practical applications of the system are discussed on the basis of the pilot study.

Data Collection

A compact computer printer for quality control spirometric data collection.

A new microcomputer, the Datamite III, was tested with a standardized group of known physiologic spirometric inputs. These test inputs were developed by the National Institute for Occupational Safety and Health, and are recommended by the Association for Advancement of Medical Instruments. They exhibit a wide range of flows and volumes along with initial and terminal hesitation in order to test, under the most severe conditions, all aspects of automated data collection, such as initiation and termination thresholds, sampling rate, back extrapolation logic and data reduction. For all measured spirometric parameters, the accuracy of the Datamite III in computing data from these curves was well within all published requirements. Correlation coefficients of 1.000 were obtained between computed and delivered values for forced expiratory volume at 1s (FEV1), forced vital capacity (FVC), FEV1/FVC, and forced expiratory flow between 25% and 75% of the FVC (FEF25-75). In addition, the Datamite III provides maximum technician support for enhanced quality control through unique program features.

Computers

Creative strategies for pediatric nursing research: data collection.

As the researcher contemplates the design and methodology of a study involving children, the age and maturity of the child are key factors for consideration. A good understanding of the child's cognitive and developmental level of functioning will greatly facilitate the explanation to the child and the process of obtaining data from the child. The successful outcome of a study may depend on how well the investigator uses this knowledge and is able to make appropriate adaptations in data collection to meet the requirements of the study design.

Child

The epidemic of HIV/AIDS in Abidjan, Côte d'Ivoire: a review of data collected by Projet RETRO-CI from 1987 to 1993.

We present a review of epidemiologic data collected by Projet RETRO-CI between 1987 and 1993 on trends in human immunodeficiency virus type 1 (HIV-1) and HIV-2 infections and on cases of AIDS in Abidjan, Côte d'Ivoire. Overall rates of HIV infection in pregnant women had already reached 10% in 1987, and have increased only modestly since then. In contrast, in 1992-1993, rates in men with sexually transmitted diseases and in female commercial sex workers reached 27 and 86%, respectively. The increases in infection rates have been largely due to transmission of HIV-1, whereas rates of HIV-2 have remained stable or have declined. Among persons with tuberculosis and hospitalized patients, rates of 46-71% have been reached, increases in recent years again being largely attributable to HIV-1. Among the 15,245 AIDS cases reported by Projet RETRO-CI, a steady decline in the male:female sex ratio has occurred over time, from 4.8:1 in 1988 to 1.9:1 in 1993. It is likely that AIDS cases were initially concentrated among a core group of female commercial sex workers and their male clients. A substantial proportion of sex workers and their clients originate from neighboring countries, and migration is likely to have contributed to the spread of HIV infection in West Africa. Including HIV-associated pulmonary tuberculosis as an AIDS-defining illness increased AIDS cases reported by Projet RETRO-CI by 13% in 1993. Despite a need for interventional research, careful description of the evolution of HIV/AIDS in this region remains essential.

Acquired Immunodeficiency Syndrome