Frank Fritsche

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Hybrid zones may be structured by environmentally independent selection against intrinsically unfit hybrids (tension zone models), or by environmentally dependent fitness differences among parental species and hybrids (ecological selection-gradient models). A 30-m slope in a mountain grassland harbors a hybrid zone of the clonal perennials, Prunella(More)
This paper presents an analysis of scientific research output of the republics of former Yugoslavia for the period 1970-2014. Thomson Reuters' Web of Science (WoS) database was used for data acquisition and 223 135 publications have been analyzed. The Yugoslav Wars were ethnic conflicts fought from 1991 to 1999 on the territory of former Yugoslavia, which(More)
On the basis of analyses of the main noise emitting equipment was carried out an audiometric test of dentists. The high frequencies of various equipment are reflected in a reduced high-frequency hearing. Significant differences became evident with increasing years of service, as well as in comparison to age adequate control groups. The high-frequency(More)