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At least 1,351 records · Page 75Linked to original sources
PubMed2001

Linkage to medical services in the Drug Abuse Treatment Outcome Study.

BACKGROUND: An episode of substance abuse treatment is an opportunity to link substance-abusing patients to medical care at a time when management of medical problems might stabilize recovery and long-term health. However, little is known about the ability of organizational linkage mechanisms to facilitate the delivery of medical care to this population. OBJECTIVES: The goal of this study was to examine whether organizational linkage mechanisms facilitate medical service utilization in drug abuse treatment programs. RESEARCH DESIGN: This was a prospective secondary analysis of the Drug Abuse Treatment Outcome Study, a national longitudinal study of drug abuse treatment programs and their patients from 1991 to 1993. Hierarchical linear models evaluated the effect of on-site delivery, formal and informal referral, case management emphasis, and transportation on the log-transformed number of medical visits at the 1-month in-treatment patient interview. MEASURES: Program directors' surveys provided organizational information, including the linkage mechanism used to deliver medical care. Patients reported the number of medical visits during the first month of drug abuse treatment. RESULTS: Exclusive on-site delivery increased medical utilization during the first month of drug abuse treatment (beta estimate, 0.22; standard error [SE], 0.06; P <0.001). Transportation services also increased 1-month medical utilization (beta estimate, 0.13; SE, 0.03; P <0.001). CONCLUSIONS: Exclusive on-site delivery of medical services increased drug abuse treatment patients' utilization of medical services in the first month of treatment. Transportation assistance warrants strong policy consideration as a facilitator of medical service delivery. Future research should clarify whether program-level linkage to medical services improves the patient-level outcomes of drug abuse treatment.

Episode of Care↗
PubMed1982

A simple linearization procedure for local fit of the Weibull survival distribution: a note on an article by Choe.

The author comments on an article by Choe concerning the use of the Weibull survival function to fit curves to infant and childhood mortality data. "As an alternative to the computer program [employed by Choe], this note gives a simple linearization procedure that is easily executed by hand calculator. This procedure allows one to check the fit of the Weibull curve locally...for a range of ages (e.g. those from which one wishes to extrapolate). It also provides a simple way to find the Weibull curve parameters of optimum local fit." The procedure is illustrated using data for the period 1970-1971 for males and females in Taiwan.

Demography↗
PubMed2006

The value of monitoring frozen section-permanent section correlation data over time.

CONTEXT: The effectiveness of the long-term monitoring of errors detected by frozen section-permanent section correlation is unknown. OBJECTIVE: To determine factors important in laboratory improvement in frozen section-permanent section discordant and deferral rates by participation in a multi-institutional continuous quality improvement program. DESIGN: Participants in the College of American Pathologists Q-Tracks program self-reported the number of anatomic pathology frozen-permanent section discordant and deferred cases in their laboratories by prospectively performing secondary review of intraoperative consultations. Laboratories participated in the program for 1 to 5 years and reported their data every quarter. We calculated mean and median discordant and deferred case frequencies and used mixed linear modeling to determine if length of participation in the program was associated with improved performance. PARTICIPANTS: One hundred seventy-four laboratories self-reported data. MAIN OUTCOME MEASURES: Mean frozen-permanent section discordant and deferred diagnostic frequencies and changes in these frequencies over time were measured. RESULTS: The mean and median frozen-permanent section discordant frequencies were 1.36% and 0.70%, respectively. The mean and median deferred diagnostic frequencies were 2.35% and 1.20%, respectively. Longer participation in the Q-Tracks program was significantly associated (P = .04) with lower discordant frequencies; 4- or 5-year participation showed a decrease in discordant frequency of 0.99%, whereas 1-year participation showed a decrease in discordant frequency of 0.84%. Longer participation in the Q-Tracks monitor was associated with lower microscopic sampling frequencies for discordant diagnoses (P = .04). Increased length of participation in the Q-Tracks program was significantly associated (P = .04) with lower deferred diagnostic frequencies. CONCLUSIONS: Long-term monitoring of frozen-permanent section correlation is associated with sustained improvement in performance.

Diagnostic Errors↗
PubMed1999

Problems in using age-stratum-specific reference rates for indirect standardization.

Disease risk in a study cohort can be compared with that in a reference population using the method of indirect standardization, adjusting for a difference in age distribution between the cohort and reference population. The common epidemiological practice is to use categorical age, typically in the form of 5-year age strata, in the standardization. This article discusses problems that arise owing to the categorization of age, including biased estimation and incorrect statistical inference on relative risk parameters. The same problems further extend to more general analyses using Poisson regression. We illustrate the problems using a hypothetical example and propose a simple remedy using linear splines. A slightly more elaborate method and its computer program are given in the appendix.

Age Distribution↗
PubMed1991

Power estimation for rank tests using censored data: conditional and unconditional.

A computer program that estimates, through simulations, the conditional power of linear rank tests for right censored data given an existing set of survival data is described. All or some observations in the existing data set may be subject to continued observation. Several possible uses for this program are given along with some examples. The program is available upon request for a nominal charge.

Clinical Trials as Topic↗
PubMed1996

Adequacy of training in preventive medicine and public health: a national survey of residency graduates.

PURPOSE: To evaluate training in general preventive medicine and public health, determining which experiences and institutional sponsors best prepare residents for practice and where improvements are most needed. METHOD: A 1991 survey of the 1,070 graduates of preventive medicine residencies from 1979 through 1989 asked the graduates to measure the adequacy of their training in preventive medicine topic areas by using a Likert-type scale of 1 (poor) to 4 (excellent). Adequacy was analyzed for variation against practice emphasis during training, training program sponsor, and other variables. The statistical methods included Student's t-test, analysis of variance and linear regression. RESULTS: A total of 797 graduates (74.5%) responded. The overall mean ratings of adequacy of training were 3.1 (SD, 0.9) for epidemiology, 2.5 (SD, 1.0) for clinical preventive medicine, 2.4 (SD, 0.9) for environmental health, 2.3 (SD, 0.9) for health administration, 2.3 (SD, 0.9) for health education and behavioral sciences, and 2.2 (SD, 0.9) for occupational medicine. Training was rated highest for topics emphasized during practice experiences. Adequacy varied by type of institution sponsoring the residency. Women rated their training as being less adequate than did men in all areas except clinical preventive medicine. The graduates tended ultimately to practice in topic areas emphasized during training. CONCLUSION: The graduates' ratings suggest that improvements are most needed in health administration, environment health, health education, and occupational medicine. Potential improvement strategies include highly focused practice experiences and increased emphasis on training in actual practice settings and community sites.

Analysis of Variance↗
PubMed2006

Nasal bone hypoplasia in trisomy 21 at 15 to 24 weeks' gestation in A high risk Thai population.

OBJECTIVE: To assess the utility of nasal bone hypoplasia in the detection of fetuses with trisomy 21 in the second trimester in a high risk Thai population. MATERIAL AND METHOD: A prospective study involving pregnant women undergoing amniocentesis due to increased risk of aneuploidy from January 2005 to December 2005. Fetal biometry and nasal bone measurements were obtained at the time of amniocentesis. Linear regression model and diagnostic tests were analyzed using the SPSS computer program. RESULTS: A total of 407 fetuses were evaluated. In euploid fetuses, the Nasal Bone Length (NBL) increased linearly with advancing gestational age. Fetuses with Down syndrome had a significantly higher proportion of NBL below the 5th centile when compared with normal fetuses (p < 0.05). The optimal nasal bone threshold associated with trisomy 21 is a BiParietal Diameter/Nasal Bone Length (BPD/NBL) ratio of 10 or greater, yielded a sensitivity of 80%, specificity of 86% for detection of trisomy 21. CONCLUSION: Nasal bone hypoplasia is associated with an increased risk of Down syndrome in the presented population.

Adult↗
PubMed1991

Immobilized pH gradients (IPG) simulator--an additional step in pH gradient engineering: II. Nonlinear pH gradients.

While in the companion paper (Tonani, C. & Righetti, P. G., Electrophoresis 1991, 12, 1011-1021) we gave the general outline of our new computer program, immobilized pH gradients (IPG) simulator, able to simulate and optimize linear pH gradients for isoelectric focusing in immobilized pH gradients, in the present report we extend the application of such a program to: (i) convex exponential gradients, (ii) logarithmic and (iii) polynomial gradients. Such gradients are meant to give equal space to protein spots in complex protein mixtures (e.g., cell lysates, biological fluids) and follow the statistical distribution of protein pI values along the pH axis. They will prove of fundamental importance in two-dimensional maps, both because they optimize the spreading of spots in the two-dimensional plane and because of the excellent reproducibility of immobilized pH gradients. The following concave exponential recipes are given: pH 3-8, pH 3-9, pH 3-10, pH 3-11, pH 4-7, pH 4-8, pH 4-9, pH 4-10, pH 4-11, pH 5-8, pH 5-9, and pH 5-10, as well as the most extended pH 2.5-11 interval. Two interesting logarithmic gradients are described: pH 3-6 and pH 3-7 and one sigmoidal (derived with a polynomial of 5th degree): pH 3-11.

Chemical Engineering↗
PubMed1994

THE SWIMMING OF UNIPOLAR CELLS OF SPIRILLUM VOLUTANS: THEORY AND OBSERVATIONS

Bright-field high-speed cinemicrography was employed to record the swimming of six unipolar cells of Spirillum volutans. A complete set of geometrical parameters for each of these six cells, which are of typical but varying dimensions, was measured experimentally. For each cell, the mean swimming linear and angular speeds were measured for a period representing an exact number of flagellar cycles (at least four and up to 12 cycles). Two independent sets of measurements were carried out for each cell, one relating to the trailing and the other to the leading configuration of the flagellar bundle. The geometry of these cells was numerically modelled with curved isoparametric boundary elements (from the measured geometrical parameters), and an existing boundary element method (BEM) program was applied to predict the mean swimming linear and angular speeds. A direct comparison between the experimentally observed swimming speeds and those of the BEM predictions is made. For a typical cell, a direct comparison of the swimming trajectory, in each of the trailing and the leading flagellar configurations, was also included. Previous resistive force theory (RFT) as well as slender body theory (SBT) models are both restricted to somewhat non-realistic 'slender body' geometries, and they both fail to consider swimming kinematics. The present BEM model, however, is applicable to organisms with arbitrary geometry and correctly accounts for swimming kinematics; hence, it agrees better with experimental observations than do the previous models.

Journal Article↗
PubMed1987

Time hierarchy in enzymatic reaction chains resulting from optimality principles.

Several optimality principles reasonable for the evolution of enzyme reaction chains are formulated, considering the kinetic parameters of the enzymes to be variables. The solutions of these parametric programming problems are studied for the case of linear kinetics and turn out to be not unique in every case. The investigations are confined to stationary states. The net flux through the chain is considered a fixed parameter. The optimality criteria concern the osmotic pressure caused by the intermediates, various relaxation times, largest time scale, and controllability. They all yield distinct time hierarchies. The influence of a constraint concerning the sum of intermediate concentrations is studied. Various combinations of the single criteria are treated as multiobjective programming problems.

Biological Evolution↗
PubMed1999

On the design of BSB neural associative memories using semidefinite programming.

This article is concerned with the reliable search for optimally performing BSB (brain state in a box) neural associative memories given a set of prototype patterns to be stored as stable equilibrium points. By converting and/or modifying the nonlinear constraints of a known formulation for the synthesis of BSB-based associative memories into linear matrix inequalities, we recast the synthesis into semidefinite programming problems and solve them by recently developed interior point methods. The validity of this approach is illustrated by a design example.

Association↗
PubMed2001

Visual Cloning 2000: a DNA sequence analysis program.

VC2000 is a recommendable, easy-to-use and affordable program suited particularly to plot maps of both plasmids and linear DNA fragments for the documentation of cloning procedures. It comes with basic tools for sequence analysis that assist this major utility. A special feature of the program is the integration of web-based tools, providing additional analytical power and flexibility. In this way the user is supplied with the latest versions of these applications.

Cloning, Molecular↗
PubMed1979

Computer programs for analysis of nucleic acid hybridization, thermal denaturation, and gel electrophoresis data.

Computer programs for the analysis of data from techniques frequently used in nucleic acids research are described. In addition to calculating non-linear, least-squares solutions to equations describing these systems, the programs allow for data editing, normalization, plotting and storage, and are flexible and simple to use. Typical applications of the programs are described.

Computers↗
PubMed2001

Ruptured appendicitis among children as an indicator of access to care.

OBJECTIVE: To determine factors associated with ruptured appendicitis among children, using administrative databases. Insurance-related differences in the risk of ruptured appendix among adults in California have previously been described (Braveman, Schaaf, Egerter, et al. 1994). DATA SOURCES/STUDY SETTING: State of Maryland Medicaid claims data for children < or = 18 years of age from 1989 to 1993 and hospital discharge data for children < or = 19 years of age from 1989 to 1994 were analyzed. STUDY DESIGN: Administrative data analysis pre- and post-implementation of a Medicaid managed care program called Maryland Access to Care. DATA COLLECTION/EXTRACTION METHODS: Medicaid claims and hospital discharge ICD-9-CM codes were used to define hospitalization for ruptured and nonruptured appendicitis. Linear regression was used to model trends. Logistic regression was used to model the probability of ruptured appendicitis. PRINCIPAL FINDINGS: Among the 374 Medicaid inpatient claims for appendicitis, 37 percent were for ruptured appendicitis. Among the 5,141 hospital discharges for appendicitis, 30 percent were for ruptured appendicitis. Using Medicaid claims data, the probability of ruptured appendicitis was inversely related to age (OR = 0.86, 95% CI 0.81-0.91), white race (OR = 0.35, 95% CI 0.17-0.71) and preventive care visits (OR = 0.19, 95% CI 0.05-0.77). Using hospital discharge data, age (OR = 0.91, 95% CI 0.90-0.93) and female gender (OR = 0.87, 95% CI 0.77-0.99) were significant covariates. Insurance-related covariates were not significant in multivariate models addressing the probability of ruptured appendicitis. CONCLUSIONS: During a period of rapid managed care growth, insurance type was not associated with an increased risk of ruptured appendicitis among children in this geographic area. Age, female gender, and the number of preventive care visits are inversely related to the risk of ruptured appendix among children. The protective effect of preventive care visits suggests that a primary care relationship facilitates access to care, thus reducing delay in the management of appendicitis.

Adolescent↗
PubMed2006

Effect of wrist and forearm training on linear bat-end, center of percussion, and hand velocities and on time to ball contact of high school baseball players.

This study examined the effects of 12 weeks of wrist and forearm training on linear bat-end velocity (BV), center of percussion velocity (CV), hand velocity (HV), and time to ball contact of high school baseball players. Forty-three baseball players were randomly assigned by a stratified sampling technique to 1 of 2 training groups. Group 1 (n = 23) and group 2 (n = 20) performed the same full-body resistance exercises while training 3 days a week for 12 weeks according to a stepwise periodized model. Group 2 also performed wrist and forearm exercises 3 days a week for 12 weeks. Wrist and forearm strength were measured pre- and posttraining. Linear BV, CV, HV, and time to ball contact were recorded pre- and posttraining by a motion-capture system. A 3 repetition maximum (RM) parallel squat and bench press were measured at baseline and after 4, 8, and 12 weeks of training. Both groups showed statistically significant increases (p < or = 0.01) in linear BV, CV, and HV (m.s(-1) +/- SD) after 12 weeks of training; however, there were no differences between the 2 groups. Both groups statistically increased wrist and forearm strength (p < or = 0.05). Group 2 had statistically greater increases (p < or = 0.05) in 10 of 12 wrist and forearm strength measures than did group 1. Both groups made statistically significant increases in predicted 1RM parallel squat and bench press after 4, 8, and 12 weeks of training; however, there were no differences between groups. These data indicate that a 12-week stepwise periodized training program can significantly increase wrist and forearm strength, linear BV, CV, and HV among high school baseball players. However, increased wrist and forearm strength did not contribute to further increases in linear BV, CV, or HV.

Adolescent↗
PubMed1990

Prediction of RNA secondary structure, including pseudoknotting, by computer simulation.

A computer program is presented which determines the secondary structure of linear RNA molecules by simulating a hypothetical process of folding. This process implies the concept of 'nucleation centres', regions in RNA which locally trigger the folding. During the simulation, the RNA is allowed to fold into pseudoknotted structures, unlike all other programs predicting RNA secondary structure. The simulation uses published, experimentally determined free energy values for nearest neighbour base pair stackings and loop regions, except for new extrapolated values for loops larger than seven nucleotides. The free energy value for a loop arising from pseudoknot formation is set to a single, estimated value of 4.2 kcal/mole. Especially in the case of long RNA sequences, our program appears superior to other secondary structure predicting programs described so far, as tests on tRNAs, the LSU intron of Tetrahymena thermophila and a number of plant viral RNAs show. In addition, pseudoknotted structures are often predicted successfully. The program is written in mainframe APL and is adapted to run on IBM compatible PCs, Atari ST and Macintosh personal computers. On an 8 MHz 8088 standard PC without coprocessor, using STSC APL, it folds a sequence of 700 nucleotides in one and a half hour.

Algorithms↗
PubMed1991

Quality assurance in stereotactic radiosurgery using a standard linear accelerator.

Methods have recently been developed for using standard linear accelerators to perform stereotactic radiosurgery. The accuracy necessary to perform this procedure requires an intensive quality assurance program to encompass all aspects of dose calibration and mechanical integrity of the treatment unit, the treatment planning process, and treatment delivery. The programs developed at the Joint Center for Radiation Therapy (JCRT) include testing of the linear accelerator and the stereotactic system, cross checking of the treatment planning process, and a quality assurance check list of the treatment delivery procedure. This report outlines in detail the quality assurance program currently in use at the JCRT.

Humans↗