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At least 181 records · Page 10Linked to original sources
PubMed2003

Behavior of the Siemens Virtual Wedge following an interruption to beam delivery.

Investigations were made into the beam profile shape and dose delivered by the Siemens Virtual Wedge trade mark under standard operational conditions compared with those following delivery interruption on two Siemens Primus linear accelerators (Type 7445 and 8067) running different versions of control software (7.2 and 7.0, respectively). The shape of the Virtual Wedge trade mark profiles was found to be unaffected by beam delivery interruption. An increase in the dose delivered to the central axis was found when delivery was interrupted and subsequently resumed using information recorded in a recall data file on one of the accelerators. This dose increase was attributed to a difference in delivered monitor units recorded in the recall data file compared to those displayed on the linear accelerator control console.

Humans↗
PubMed1996

Development of an emergency department-based injury surveillance system.

STUDY OBJECTIVE: To describe the development of an emergency department-based injury surveillance system, to describe the problems encountered, and to briefly describe the data output and potential applications. METHODS: Within our university-based hospital system and Level I trauma center register, injury data currently exist on all ED patients. Over a 1-year period, these data sets were linked with our ED log using the hospital identification number and date of service as the key merge variables. Elements in our data set included demographic information, ED-related variables, and codes for nature of injury and circumstances of injury. Data files for 1 month were inspected manually to validate the success of the merger. Problems encountered in developing the system were summarized. RESULTS: A manual review of 1 month of data files from our hospital system, trauma register, and ED log revealed that the records of more than 97% (2,802) of 2,878 injury patients seen in our ED had additional data attached after the merger. No errors of commission were found, but errors of omission occurred. The barriers that were encountered during the development of this injury surveillance system are described. CONCLUSION: Hospital data can be linked to the ED log to create an injury surveillance system that captures valuable information on patients admitted and discharged from the ED.

Bias↗
PubMed1999

Analyzing health surveys for cancer-related objectives.

Large-scale health surveys conducted by government agencies record information on a large number of health-related variables. We review the use of these data for performing analyses that address cancer-related objectives. After describing the conduct of a large-scale health survey (the third National Health and Nutrition Examination Survey [NHANES III]), we discuss some of the issues involved in analyzing data collected in such a survey. In particular, the use of sample weights in the analysis and the importance of accounting for the complex survey design when estimating standard errors are discussed. Six applications are then presented that involve the following: 1) estimating demographic factors associated with snuff use, 2) estimating the association of type of health insurance with the probability of receiving a digital rectal examination, 3) estimating the association of body iron stores with the probability of later developing cancer, 4) estimating the changing rates of mammography screening in the United States between 1987 and 1992, 5) evaluating smoking and alcohol consumption as risk factors for digestive cancer by use of a population-based, case-control study, and 6) evaluating a randomized community-intervention experiment to encourage smoking cessation. These applications use data from the National Health Interview Survey, the NHANES I Epidemiologic Followup Study, the 1986 National Mortality Followback Survey, and the Community Intervention Trial for Smoking Cessation. The availability of public-use data files is discussed for surveys sponsored by the U.S. government that collect health-related information. We demonstrate that statistical methods and computer software are available for analyzing public-use data files of surveys to address different types of cancer-related objectives.

Alcohol Drinking↗
PubMed1990

A microcomputer program to compare the survival probability of patient groups.

A program was written to calculate the probability of patient survival, tabulate the results in the form of a life table and compare two patient groups by the Mantel-Haenszel (logrank) test on a microcomputer. The program reads data in either a text form or the format of data files of the dBASE III/III plus (Ashton-Tate). The program is entirely menu-driven and extremely easy to use. The structure of the data files and the function of the program are described. This program is useful to those without easy access to mainframe computers.

Humans↗
PubMed1995

Analysis of ciliary beat frequencies in hamster oviducal explants.

We have developed a simple direct method, requiring minimal manipulation, to measure beat frequencies of the cilia on the external surface of hamster oviducal infundibula in vitro. Two perfusion chambers (closed and open) were used; both can be hand-made in a few minutes and discarded after use. Ciliary beat frequencies were determined by measuring variations in light intensity with time in a single pixel positioned over a video image of the beating cilia. Data files were collected using Image 1 software and later transferred to PSI Plot or Lotus 123 spreadsheets for analysis by counting the number of brightness peaks recorded per second or by subjecting the data to Fourier transformation with or without smoothing. These methods of analysis gave similar results. To verify that Image 1 data files contain accurate representations of CBF, videotapes of beating cilia were made and subjected to frame-by-frame analysis. Image 1 interfaced with a standard video camera was found to collect reliable data over a beat frequency range of 0-15 cycles/sec. In some Fourier transforms, secondary peaks were observed and were shown to represent cilia beating at more than one frequency in a sampled region. Coefficients of variation for repeated measurements taken on the same region varied from 4.1% to 9.0%. Small but significant differences were found between beat frequencies at different regions of the same oviduct. When chambers were perfused discontinuously and measurements of beat frequency were made at least 5 min after each perfusion, no effect of perfusion on frequencies was observed. However, during continual perfusion of the open chamber, a slight but significant increase in beat frequency was observed after perfusion was initiated. Muscle contraction, which sometimes occurs in the open chamber, did not affect beat frequency measurements. Infundibula could be stored at 4 degrees C overnight without any negative effect on beat frequencies. Cold storage also reduced muscle contraction. Placement of a small coverslip on infundibula in the open chambers was also found to reduce muscle contraction and facilitate beat frequency measurements. Coverslipping did not affect beat frequencies. This method of beat frequency analysis will be valuable for analyzing factors that regulate or influence cilia in mammalian oviducts.

Analysis of Variance↗
PubMed1995

The Atlas of Health and Working Conditions by Occupation. 2. A comparison with the "Atlas of Health and Working Conditions in the Construction Industry".

The results of the general Atlas of Health and Working Conditions by Occupation were compared with the results of the Atlas of Health and Working Conditions in the Construction Industry. Both are based on questionnaire data from periodical occupational health surveys [POHSs]. The scores on most of the items showed considerable differences between the two atlases, partly due to differences in the regional origin of the data. Therefore, direct comparisons between the atlases are biased by regional differences. To study the reliability and the generalizability of the results of both atlases, similarities between the data files with respect to occupations in the construction industry were studied. Most of the items on working conditions, especially those with a widespread distribution, showed a close resemblance between the data files in terms of the relative position of an occupation compared to other occupations in the construction industry. The items on health showed less resemblance, except for the items on musculoskeletal complaints, which showed results similar to those of the work items. These results indicate the reliability and generalizability of the judgements based on both atlases outside the regions of origin, as far as items with a widespread distribution are concerned. Therefore, we recommend the aggregation of POHS data on a national scale, taking regional differences into account. In that way, a greater number of occupations will be described and the reliability of the results will be enhanced.

Adult↗
PubMedDate not supplied

Development of a computer linkage system for a blood recipient notification program in Nova Scotia.

OBJECTIVES: To assess the potential uses of computer-assisted record linkage in the surveillance of infectious diseases, using the Nova Scotia blood recipient notification program as the example. METHODS: We developed a computer-assisted, multiple-pass, probabilistic record linkage to link records for blood recipients identified by the Nova Scotia notification program (Nova Scotia Phase I Blood Bank File information) with corresponding Nova Scotia Health Card Registration File records to obtain current mailing addresses to contact potentially living recipients. We used variables available from both files (e.g., name, date of birth, gender, and health care registration number) to link records, after eliminating duplicates/deceased cases. RESULTS: Among 23,925 eligible records in the Nova Scotia Phase I Blood Bank File (1984-1990), there were 1,818 (7.8%) duplications and 8,675 deceased cases, leaving 13,432 cases for linkage. 8,713 (65%) cases were successfully linked to the 1998 Health Card Registration Data File for current mailing addresses. INTERPRETATION: Multiple-pass linkage seems acceptable for maximizing detection of correctly matched records for look-back projects. To overcome quality/lack of information obstacles, future look-back linkages should explore the use of supplementary data files (tax files, voter lists, license files, other provincial databases) to obtain most current addresses.

Disease Notification↗
PubMed1984

Relationship between physical, psychological, social, and environmental variables and subjective sleep quality.

In a survey study of patients of a general practitioner the relationship between sleep quality and a heterogeneous set of other variables was examined. The data file was divided randomly, and a two-staged multiple regression analysis was performed on each half. The two resulting regression equations were cross-validated on the data of the other data file. The variables mood, age, and use of medicine proved to have the most significant relationship to sleep quality.

Adult↗
PubMed1994

Interlaboratory variability of rotational chair test results. Interlaboratory Rotational Chair Study Group.

Test-retest reliability of rotational chair testing for a single facility has previously been examined by others. The actual data analysis methods, however, have received far less attention. The variety of both hardware and software currently used theoretically may affect the results for a given subject tested at different facilities. The purposes of this study were, first, to quantify the amount of variability in the analysis of identical raw data files at multiple rotational chair testing facilities by using automated analysis; second, to evaluate the effect of operator intervention on the analysis; and third, to identify possible sources of variability. Raw data were collected from 10 normal subjects at 0.05 Hz and 0.5 Hz (50 degrees per second peak velocity). Diskettes containing raw electro-oculogram data files were then distributed to eight participating laboratories for analysis by two methods: (1) using automated analysis algorithms and (2) using the same algorithms but allowing operator intervention into the analysis. Response parameters calculated were gain and phase (re: velocity). The SD of gain values per subject for automated analysis ranged from 0.01 to 0.32 gain units and of phase values from 0.4 to 13.7 degrees. For analysis with operator intervention, the SD of gain values ranged from 0.02 to 0.10 gain units and of phase values from 0.4 to 4.4 degrees. The difference between automated analysis and analysis with operator intervention was significant for gain calculations (p < 0.02) but not for phase calculations (p > 0.05). This study demonstrates significant variability in automated analysis of rotational chair raw data for gain and phase.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2000

An integrated web interface for large-scale characterization of sequence data.

Large-scale genome projects require the analysis of large amounts of raw data. This analysis often involves the application of a chain of biology-based programs. Many of these programs are difficult to operate because they are non-integrated, command-line driven, and platform-dependent. The problem is compounded when the number of data files involved is large, making navigation and status-tracking difficult. To demonstrate how this problem can be addressed, we have created a platform-independent Web front end that integrates a set of programs used in a genomic project analyzing gene function by transposon mutagenesis in Saccharomyces cerevisiae. In particular, these programs help define a large number of transposon insertion events within the yeast genome, identifying both the precise site of transposon insertion as well as potential open reading frames disrupted by this insertion event. Our Web interface facilitates this analysis by performing the following tasks. Firstly, it allows each of the analysis programs to be launched against multiple directories of data files. Secondly, it allows the user to view, download, and upload files generated by the programs. Thirdly, it indicates which sets of data directories have been processed by each program. Although designed specifically to aid in this project, our interface exemplifies a general approach by which independent software programs may be integrated into an efficient protocol for large-scale genomic data processing.

Clinical Laboratory Information Systems↗
PubMed1982

A generalized plotting program, written in BASIC for scientific data.

A software package for the hardcopy graphic display of two-dimensional data had been developed. It is written in BASIC and is compatible with a microcomputer interfaced to an intelligent digital plotter. The core of the package is a plotting program. It features a command menu that displays 15 user-controllable parameters. Most of these parameters are automatically tabulated and can be changed in an interactive manner. The data which is plotted is either entered by hand or read from pre-existing data files. The package has several other important features. One subroutine within the plotting program determines and draws the best fit of a curve through a set of points. Using another program, the user can edit and manipulate the information contained in data files. All the program commands are written in simple and precise language, therefore the user needs no previous experience with computers. Furthermore the programs can be easily modified to suit personalized needs.

Computers↗
PubMedDate not supplied

Optical micturition interval monitor for experimental animals.

INTRODUCTION: In the past several years, overactive bladder and urinary incontinence have become recognized as an unmet therapeutic need. Some new pharmacologic treatments have recently been described, and new approaches are in development by a number of companies. For preclinical studies, accurate assessment of micturition patterns over a long period of time is important for successful new drug development. Current methodologies rely upon collecting urine in cups positioned upon force displacement transducers and either collecting very large digitized data files, or producing long polygraph tracings. METHODS: The methodology described in this paper utilized an optical device consisting of an infrared photodiode and a matched phototransistor as an electronic drop counter. The device can monitor the appearance of urine flow as it exits the bottom of a metabolic cage. RESULTS: Because the device only collects data when there is an event, the resulting data files are significantly smaller, and there is no need to assure that the urine collection cups do not fill-up and overflow. Data were collected using both methodologies and the results compared. In every experiment, the data derived from the optical device were in very close agreement with the actual micturition pattern recorded by the cup-force transducer method. DISCUSSION: This optical method represents a simple and reliable technique for monitoring micturition patterns in experimental animals.

Animals↗
PubMed1997

Screening of rice genes from the cDNA catalog using the data obtained by protein sequencing.

The partial amino acid sequences of 121 rice proteins separated by two-dimensional gel electrophoresis (2D-PAGE), were determined for a protein sequence data file. In the Rice Genome Research Program (RGP), more than 20,000 cDNA clones randomly selected from rice cDNA libraries have been sequenced to construct a cDNA catalog. Complimentary DNAs encoding about 30% of proteins in the protein sequence data file could be identified in the catalog by computer search. It was deduced that 20,000-40,000 genes are present in the rice genome. Only half of about 20,000 cDNAs sequenced in the RGP, corresponding to 1/4-1/2 of genes present in the entire rice genome, should have unique sequences after considering gene redundancy. This is consistent with the fact that the cDNAs encoding about 30% of the sequenced proteins could be identified in the catalog. If the size of the cDNA catalog is enlarged further, cDNAs encoding all proteins separated by 2D-PAGE could be easily identified from the catalog by using the protein sequence data.

Amino Acid Sequence↗
PubMedDate not supplied

A sampling method for estimating the accuracy of predicted breeding values in genetic evaluation.

A sampling-based method for estimating the accuracy of estimated breeding values using an animal model is presented. Empirical variances of true and estimated breeding values were estimated from a simulated n-sample. The method was validated using a small data set from the Parthenaise breed with the estimated coefficient of determination converging to the true values. It was applied to the French Salers data file used for the 2000 on-farm evaluation (IBOVAL) of muscle development score. A drawback of the method is its computational demand. Consequently, convergence can not be achieved in a reasonable time for very large data files. Two advantages of the method are that a) it is applicable to any model (animal, sire, multivariate, maternal effects...) and b) it supplies off-diagonal coefficients of the inverse of the mixed model equations and can therefore be the basis of connectedness studies.

Algorithms↗
PubMedDate not supplied

Statewide analysis of serum prostate specific antigen levels in Louisiana men without prostate cancer.

OBJECTIVES: To examine age, racial, and regional differences in serum PSA levels among men in Louisiana. METHODS: From January 1, 2001 through December 31, 2001, there were 10,012 serum PSA tests performed at Louisiana Health Care Services Division (HCSD) hospitals. Manual and electronic data mining were performed to select the earliest PSA value in those men who had multiple determinations. This PSA data file was then linked with those of the Louisiana Tumor Registry and from HCSD pathology laboratories, all matched cases were removed. Men younger than 40 years and older than 79 years were excluded from this study. The final data file contained 7,258 men, of whom 4,244 were African-Americans and 3,014 were Caucasians. Comparisons of median and geometric mean serum PSA level were made between and among races for each age-decade as well as among the hospitals to assess for racial and regional differences. RESULTS: Median PSA levels were statistically significantly higher in African-American men than in Caucasian men for each age group (p < or = 0.0002). The median PSA (ng/ml) for African-American men was 0.7, 0.9, 1.3, and 2.3 for age-decades 40-49, 50-59, 60-69, and 70-79, respectively, whereas for Caucasian men the median PSA levels were 0.8, 1.2, and 1.6 for age-decades 50-59, 60-69, and 70-79, respectively. Nonparametric analysis of variance did not demonstrate a regional pattern of PSA values among the hospitals. CONCLUSIONS: In a first statewide analysis of age and racial differences of serum PSA levels, African-American men without prostate cancer had significantly higher serum PSA levels than their age-matched Caucasian male counterparts. Additionally, there were no regional patterns of PSA values among the racial groups.

Adult↗
PubMed2006

Self-test software for PowerPoint: a tool for self-learning.

RATIONALE AND OBJECTIVES: We developed self-test software to improve self-learning efficiency using Microsoft PowerPoint data files. CONCLUSION: This tool can be run on IBM-compatible computer under Microsoft Windows. It is a new useful and interactive tool for self-learning. This tool allows users to do view the cases in the PowerPoint data files by random or sequentially. Goal-oriented effective self-learning is possible from methods that conjecture the possible differential diagnosis without promptly seeing correct diagnosis. Thus effective and interactive self-learning is possible.

Computer Graphics↗
PubMed1991

Validation of the cause of renal failure of patients in the Medicare end-stage renal disease program.

Studies addressing the epidemiological issues of end-stage renal disease (ESRD) and the implications for health resource allocations are valuable, especially because the Medicare ESRD program is expected to continue growing during the next decade. Studies on trends in the causes of renal failure have benefited from Medicare's extensive data files on ESRD patients. However, no studies have been published that validate the cause of renal failure field in the Medicare files. The primary disease causing renal failure for over 10,000 New York State patients in the Medicare ESRD program was compared with their hospital discharge diagnoses. Of these patients, 8,730 (83%) had a known cause of renal failure in the Health Care Financing Administration (HCFA) data files. Eighty-nine percent of these patients' primary cause of renal failure was matched with the same major hospital diagnostic code. Patients with diabetes and glomerulonephritis had the highest overall match rates (96% to 97%). Patients with polycystic kidney disease and causes of renal failure other than the four major causes had the lowest match rates (75% to 76%), but these match rates increased to 84% to 87% for patients hospitalized more than five times. Some differences in match rate by age and race were found. These findings suggest that HCFA data on the causes of renal failure of ESRD patients are reasonably accurate and can be used successfully to study a variety of issues related to the diseases leading to chronic renal failure.

Adult↗
PubMed1996

Factors influencing international comparisons of dairy sires.

A method of dairy sire evaluation across multiple countries is described. Factors influencing this method are overestimation of genetic trends within countries, inclusion of evaluations of imported bulls, years of birth of the bulls included in the analysis, and estimates of genetic correlations between countries. Fall 1994 evaluations for milk, fat, and protein yields from Canada (4559 bulls), Germany (5894 bulls), and France (8419 bulls) were used to study the effect of these factors. After inclusion of ancestors there were 21,555 bulls in total. Eight data files were created based on combinations of three factors: 1) bulls born from 1970 to present versus bulls born from 1979 to present, 2) all bulls included versus imported bulls omitted, and 3) official Canadian evaluations for all lactations versus Canadian evaluations for first lactation only. Separate evaluations for two of the data files assumed a uniform genetic correlation of 0.995 between countries. Rankings of top bulls from analyses were affected by all factors to various degrees, depending on the country. Evaluations of imported bulls have an effect on bull rankings and probably should not be included. An assumed uniform genetic correlation between countries of 0.995 may not be appropriate. Proper methods and data for estimation of the genetic correlation between countries should be sought.

Animals↗