The text sums up the conclusions of the author’s sociolinguistic investigations conducted
(particularly in the form of questionnaires) in years 1996-2001 and published in the monograph Sprachverhalten und ethnische Identität. Sorbische Schüler an der Jahr tausendwende (Language Attitudes and Ethnic Identity. Sorbian Students at the Turn of the
Millennium) in 2005. Investigations were carried out at many Sorbian schools in Upper
Lusatia and were aimed at ethnic awareness of the students, their choice/use of Sorbian or
German, attitude to both languages, and reception of culture among young Sorbs aged 11-19. The author mainly focused on the Sorbian Grammar School in Bautzen (Budyšin in Sorbian). In order to make the generalisation of the acquired outcomes possible, analogical surveys were also conducted at lower secondary schools in the villages of Crostwitz/Chrósćicy, Ralbitz/Ralbicy, Panschwitz-Kuckau/Pančicy-Kukow, Räckelwitz/Worklecy, Radibor/ Radwor, and in the municipality of Bautzen/Budyšin. The findings presented, analyzed and interpreted in the páper can, to a great degree, be in
general applied to the present-day young Sorbian population as a whole. Simultaneously, they yield data for possible comparisons with the situation of other minority ethnic groups in Europe (e.g. the Welsh, the Romansh, Breton...).
Some functional representation theorems for monadic n-valued Luk asiewicz algebras (qLkn-algebras, for short) are given. Bearing in mind some of the results established by G. Georgescu and C. Vraciu (Algebre Boole monadice si algebre L ukasiewicz monadice, Studii Cercet. Mat. 23 (1971), 1027–1048) and P. Halmos (Algebraic Logic, Chelsea, New York, 1962), two functional representation theorems for qLkn-algebras are obtained. Besides, rich qLkn-algebras are introduced and characterized. In addition, a third theorem for these algebras is presented and the relationship between the three theorems is shown.
The problem of understand natural processes as factors that restrict, limit or even jeopardize the interests of human society is currently of great concern. The natural transformation of flood waves is increasingly affected and disturbed by artificial interventions in river basins. The Danube River basin is an area of high economic and water management importance. Channel training can result in changes in the transformation of flood waves and different hydrographic shapes of flood waves compared with the past. The estimation and evolution of the transformation of historical flood waves under recent river conditions is only possible by model simulations. For this purpose a nonlinear reservoir cascade model was constructed. The NLN-Danube nonlinear reservoir river model was used to simulate the transformation of flood waves in four sections of the Danube River from Kienstock (Austria) to Štúrovo (Slovakia) under relatively recent river reach conditions. The model was individually calibrated for two extreme events in August 2002 and June 2013. Some floods that occurred on the Danube during the period of 1991-2002 were used for the validation of the model. The model was used to identify changes in the transformational properties of the Danube channel in the selected river reach for some historical summer floods (1899, 1954 1965 and 1975). Finally, a simulation of flood wave propagation of the most destructive Danube flood of the last millennium (August 1501) is discussed.
The external derivative d on differential manifolds inspires graded operators on complexes of spaces Λr g ∗ , Λr g ∗ ⊗ g, Λr g ∗ ⊗ g ∗ stated by g ∗ dual to a Lie algebra g. Cohomological properties of these operators are studied in the case of the Lie algebra g = se(3) of the Lie group of Euclidean motions.