Biomedical subjects

F Bergel

Publications and source records attributed to F Bergel.

At least 19 recordsLinked to original sources

PubMed1996

Implementation of linear and quadratic discriminant analysis incorporating costs of misclassification.

Discriminant analysis plays an important role in biological and medical research. In practice, standard linear and quadratic methods are often applied which assume equal costs of misclassification. However, there can be situations where misclassifications between certain groups may be more serious than between other groups. Such considerations can be taken into account by using classification methods which incorporate misclassification costs. The widely applied statistical packages BMDP, SAS, and SPSS do not offer the possibility of using unequal misclassification costs for discriminant analysis with more than two groups. In this paper a menu-driven, user-friendly PC program written in Borland Pascal is introduced which performs linear and quadratic discriminant analysis for g > or = 2 groups allowing for the incorporation of misclassification costs.

Bias↗

PubMed1995

A PC program for unbiased and predictive linear and quadratic discriminant analysis.

Discriminant analysis plays an important role in biological and medical research. The most popular methods of discrimination in practical applications are parametric methods like linear and quadratic discriminant analysis. However, there exist modifications of these approaches, namely unbiased and predictive discriminant analysis, which lead to reduced error rates in certain situations. In this paper a menu-driven, user-friendly PC program written in Borland Pascal 7.0 is introduced which performs unbiased and predictive linear and quadratic discriminant analysis.

Bias↗

PubMed1992

Urine test strips: reliability of semi-quantitative findings under tropical conditions.

Semi-quantitative urinalysis with urine reagent strips (URS) for erythrocyturia (EU), leucocyturia (LU) and proteinuria (PU) was performed in Congolese and Sudanese school children with Schistosoma haematobium and/or S. mansoni infection. Quantitative urinalysis was performed on the same specimen using microscopy and a Neubauer counting chamber for EU and LU and the Coomassie blue dye-binding assay for PU. Microscopically detectable EU of more than 10 cells/microliters was found in 63% of all samples and LU of more than 20 cells/microliters was found in 60% of all samples. With the Coomassie blue method, PU of more than 150 mg/l was detected in 51% of all samples. URS gave positive results of grade 1-3 for EU in 69% of all samples, for LU in 63% of all samples and for PU in 66% of all samples. The sensitivity and specificity of URS compared with standard reference methods were as follow: EU 95% and 75%, LU 81% and 81% and PU 90% and 56%. When the results of all three test were combined, URS differentiated abnormal from normal urine specimens with a sensitivity of 94% and a specificity of 70%. Median quantitative results showed a good correlation with semiquantitative URS readings for all parameters, but there was a wide range of URS scores. We concluded that URS sensitivity detect urinary abnormalities and thus may be used as a general screening method under field conditions when more specific methods cannot be performed.(ABSTRACT TRUNCATED AT 250 WORDS)

Congo↗

PubMed1980