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PubMedDate not supplied

Possibilities of the application of regression analysis and analysis of variance. II. Assessment and comparison of acute toxicity: presentation and practical application of the interactive computer program "LD50-MORTALITY".

The paper presents the interactive computer program "LD50-MORTALITY", written in the program language BASIC and used for the assessment of the acute toxicity (calculation of LD50 and other LD values) based on the algorithm of the Finney's probit analysis method. The correctness of the program execution has been shown on the test-example of assessment the acute toxicity (LD50 an LD90) of insecticide rotenone on Macrosiphonelia sanborni (the example is taken from the literature on probit analysis presentation). The results obtained by the program execution have been identical or similar to those given in the example. The results of the assessment and comparison of LD50 have also been presented.

Algorithms↗
PubMed1999

Genome-wide linkage analysis using genetic variance components of alcohol dependency-associated censored and continuous traits.

We used variance-components analysis to investigate the additive genetic effects regulating some of the phenotypes included in the GAW11 data set. Variance-components models were fitted using Gibbs sampling methods in BUGS v 0.6. Linkage analyses for both multivariate normal (MvN) traits and right censored survival times (age-of-onset) were based upon standard Haseman-Elston identity-by-descent sib-pair methods applied directly to traits showing evidence of substantial additive genetic determination (residualized for any important covariates) and to the estimated sigma A2 residuals for those traits. Harm avoidance behavior (TPQ subscale) showed evidence of linkage to markers on chromosomes 1, 13, and 18. P300 levels at the Fp1 site showed evidence of linkage to markers on chromosomes 2, 3, 9, 12, 17, 19, and 20. Platelet monoamine oxidase B (MAOB) levels showed evidence of linkage to D4S1651. The age-of-onset for ALDX1 in those over 30 years old showed evidence of linkage to markers on chromosomes 1, 6, 14, and 15. The age-of-onset for the more strictly defined ALDX2 in those over 30 years old showed evidence of linkage to markers on chromosomes 7 and 14. These results are consistent with a complex, multifactorial susceptibility to alcohol dependency.

Age of Onset↗
PubMed1987

Cuprophan reuse and intradialytic changes of lung diffusion capacity and blood gases.

The changes in arterial blood gas, pulmonary function tests, leukocyte counts and complement activation were evaluated during first use and subsequent reuse of cuprophan dialyzers. The dialysate buffer was bicarbonate. Reuse of cuprophan dialyzers significantly attenuated the fall in leukocyte counts and the rise in C3a des Arg seen during first use dialysis. First use dialysis also caused a drop in arterial paO2 from 93.0 +/- 12.4 mm Hg to a nadir of 82.8 +/- 12.6 mm Hg at 60 minutes (P less than 0.01). PaO2 levels did not change when reused dialyzers were employed (93.7 +/- 12.2 before dialysis and 96.4 +/- 15.2 mm Hg at 60 minutes, P greater than 0.05). Intradialytic paO2 curves obtained during first use and reuse were significantly different by variance analysis (P less than 0.001). There was also a significant decline in lung diffusion capacity (DLCO, from 30.70 +/- 8.89 to 23.77 +/- 7.76 ml/min X mm Hg, P less than 0.01) and transfer factor (KCO, from 6.07 +/- 1.97 to 5.65 +/- 2.13 ml/min X mm Hg, P less than 0.01), during first use at one hour after initiation of dialysis. This decrease was entirely prevented during reuse, (P less than 0.001 vs. first use by variance analysis). Percentual changes in leukocyte counts and C3a des Arg concentration on one hand, and in paO2, DLCO and KCO on the other were significantly correlated to each other. Other factors with a possible influence on intradialytic pulmonary function such as ultrafiltration volume, dialysate buffer composition, evolution of intradialytic blood pH and cardiac output, were all identical under both experimental conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Computer analysis of some bacteriological, biological and physiochemical parameters of the coastal water of Lake Balaton.

Some 61 coastal water samples were taken at four definite points of Balaton Lake. Seventeen parameters of each sample characterizing the quality of the water were studied by means of multiple correlation and regression analysis, one-way variance analysis and by factor analysis with the help of BMD computer program. Uni- and multilateral relationships could be observed among the single parameters. On the basis of the results of factor analysis six factors--phytoplankton system, anthropogenic effect, own bacterial system of the lake, nitrogen circulation, hydrocarbonate and reactive phosphate system and NH+4 circulation--could be separated. Significant qualitative differences could be found along the longitudinal axis of Balaton. It could be also demonstrated that the water of the lake in its present condition is suitable for the proliferation of bacteria. Further and deeper examinations are necessary for a better understanding of the biochemical and biological processes.

Analysis of Variance↗
PubMed2000

The consequence of ignoring a nested factor on measures of effect size in analysis of variance.

Although the consequences of ignoring a nested factor on decisions to reject the null hypothesis of no treatment effects have been discussed in the literature, typically researchers in applied psychology and education ignore treatment providers (often a nested factor) when comparing the efficacy of treatments. The incorrect analysis, however, not only invalidates tests of hypotheses, but it also overestimates the treatment effect. Formulas were derived and a Monte Carlo study was conducted to estimate the degree to which the F statistic and treatment effect size measures are inflated by ignoring the effects due to providers of treatments. These untoward effects are illustrated with examples from psychotherapeutic treatments.

Analysis of Variance↗
PubMed1988

Sodium channel subconductance levels measured with a new variance-mean analysis.

The currents through single Na+ channels were recorded from dissociated cells of the flexor digitorum brevis muscle of the mouse. At 15 degrees C the prolonged bursts of Na+ channel openings produced by application of the drug DPI 201-106 had brief sojourns to subconductance levels. The subconductance events were relatively rare and brief, but could be identified using a new technique that sorts amplitude estimates based on their variance. The resulting "levels histogram" had a resolution of the conductance levels during channel activity that was superior to that of standard amplitude histograms. Cooling the preparation to 0 degrees C prolonged the subconductance events, and permitted further quantitative analysis of their amplitudes, as well as clear observations of single-channel subconductance events from untreated Na+ channels. In all cases the results were similar: a subconductance level, with an amplitude of roughly 35% of the fully open conductance and similar reversal potential, was present in both drug-treated and normal Na+ channels. Drug-treated channels spent approximately 3-6% of their total open time in the subconductance state over a range of potentials that caused the open probability to vary between 0.1 and 0.9. The summed levels histograms from many channels had a distinctive form, with broader, asymmetrical open and substate distributions compared with those of the closed state. Individual subconductance events to levels other than the most common 35% were also observed. I conclude that subconductance events are a normal subset of the open state of Na+ channels, whether or not they are drug treated. The subconductance events may represent a conformational alteration of the channel that occurs when it conducts ions.

Analysis of Variance↗
PubMed1999

The implementation of clinical paths for six common urological procedures, and an analysis of variances.

OBJECTIVE: To evaluate the outcomes of treatment after implementing clinical paths for six common urological procedures, and analyse the variances from these paths. PATIENTS AND METHODS: The study comprised 1006 consecutive patients treated according to the recommendations of the clinical path for six common urological procedures; the results of treatment were compared with those from 1006 patients treated by the same physicians before implementing the clinical paths. Total admission charges were divided into five categories, i.e. operation and anaesthesia, laboratory, radiology, pharmacy and other. The differences in these five categories before and after implementation were determined; the variance data were also tracked and analysed. Five quality indicators were monitored during implementation and compared with the data before implementation. RESULTS: The mean length of hospital stay (LOS) and admission charges were significantly lower (P=0.03 and P<0.01) after implementation. The charges for laboratory, radiology, pharmacy and other were significantly decreased after the use of clinical paths. The common variations from the clinical paths were patient-related variance (33%) and discharge variance (26%). Variances affecting the LOS only or the admission charge only were more common than those affecting neither the LOS nor admission charges (both P<0.01), or both (both P<0.01). After implementation, the results of the five quality indicators were significantly improved and the number of patients with surgical complications was significantly reduced (P<0. 01), but the mortality and readmission rate did not increase. CONCLUSIONS: The implementation of clinical paths for six common urological procedures decreased the LOS, admission charges and surgical complications, and improved the quality of care. During implementation, variances can affect the LOS and/or admission charges.

Analysis of Variance↗
PubMed2001

Experimental design, analysis of variance and slide quality assessment in gene expression arrays.

A microarray experiment is a sequence of complicated molecular biology procedures relying on various laboratory tools, instrumentation and experimenter's skills. This paper discusses statistical models for distinguishing small changes in gene expression from the noise in the system. It describes methods for assigning statistical confidence to gene expression values derived from a single array slide. Some of the theory is discussed in the context of practical applications via software usage.

Algorithms↗