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Logistyka
|
2014
|
nr 4
4821--4828, CD6
EN
In economics research also in logistic it is often important to compare structures. The issue of comparison multivariate structures based on data in contingency tables was analyzed. The permutation rank–based tests were applied in the multivariate ordinal data structure comparison. Permutation tests could be used in practice because of flexibility of the test statistic and minimal assumptions. In the case of Kendell’s tau statistic verification of hypothesis on similarity (stability) of the structures is equal to verify the hypothesis on independence of variables. The application of the proposed procedure on the example of the high–bay warehouse was illustrated.
PL
W badaniach ekonomicznych również w logistyce często istotne jest porównywanie struktur. Analizowano zagadnienie dotyczące porównania wielowymiarowych struktur na podstawie danych w tablicach kontyngencji. Permutacyjny test oparty na rangach został zastosowany do porównywania wielowymiaro-wych, mierzonych na skali porządkowej danych. Testy permutacyjne mogą być wykorzystane w praktyce ze względu na dużą elastyczność statystyki testowej przy minimalnych założeniach. W przypadku statystyki tau Kendell’a weryfikacja hipotezy o podobieństwie (stabilności) struktur jest tożsama z weryfikacją hipotezy o niezależności zmiennych. Zastosowano proponowaną procedurę testową dla danych pochodzących z magazynu wysokiego składowania.
2
Content available remote Genetic diversity in relation to secondary succession of forest tree communities
EN
Forest succession is a fundamental ecological process, which has significant implications for the biological, biophysical, and biogeochemical processes in an ecosystem. Genetic diversity is not only a product of the number of species present in a given area, but also of successional change from colonization of gaps by pioneer species to mature climax forest. Genetic diversity should be higher in earlier successional stages than in later stages because high environmental predictability in later successional stages favours low genetic diversity. In the present study the relationship between secondary succession and genetic diversity was explored in eight stands of characteristic tree communities in the Thuringian forest area (Germany). Each of the eight stands was subdivided into six plots in a grid of 40 x 40 m to detect as much as possible tree species and genetic variants within the forest tree community and successionspecific structures. To define secondary succession, the mean Ellenberg indicator values for light and nitrogen in the herb layer, weighted for coverage, as well as the percentage of climax tree species in naturally regenerated stands were used. All species and genotype diversities based on the investigated tree species were calculated by the so-called Hill numbers. The results showed that the Gregorius's Covariation (C) of secondary succession with the transspecific genotype diversity as well as the transspecific genotype diversity per species for the enzyme systems AAT, HEK, PGI, MDH, IDH as well as the AFLP trait was statistically significant in several relationships. The transspecific genotype diversities were often significantly greater in the earlier successional stages than in the later stages. Selection effects during replacement of light and nitrogen demanding species and plant communities by more economical and competitive species such as Abies alba Mill. and Fagus sylvatica L. probably dominated in the study. Based on the results of the study, we conclude that genetic diversity may be an essential attribute of stages of secondary succession that should be further explored because of its relation to adaptability and ecological stability.
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