Autor: Mackiewicz, Dorota - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Komputerowe modelowanie ewolucji genomów
Computer modelling of genome evolution
Autorzy:: Cebrat, Stanisław
Mackiewicz, Dorota
Waga, Wojciech
Powiązania:: https://bibliotekanauki.pl/articles/1196824.pdf
Data publikacji:: 2009
Wydawca:: Polskie Towarzystwo Przyrodników im. Kopernika
Opis:: A dozen years of computer simulations of age structured populations composed of individuals represented by their diploid genomes show how evolution of the genetic pool of populations depends on the population size, intragenomic recombination rate and promiscuity. The cross-over rate and the effective population size decide about the probability of separation of genes located on one chromosome during the reproduction. If this probability is low, the genes are inherited as a cluster. Purifying selection, which tries to minimise the number of mutations by eliminating defective genes from a cluster, seems to be the more costly strategy and genomes may chose the strategy of complementation. Switching between the two strategies - purifying selection and complementation of haplotypes - has a character of transition. Results of the human chromosome analyses suggest that our chromosomes evolve in conditions close to this transition and formation of clusters and their complementation should be expected. The distribution of genes in the complementing clusters is not random and it is specific for evolving populations. Sympatric speciation, where one species splits into several within the same territory, should be considered as a very common phenomenon in spatially distributed populations and, in fact, it is observed during the computer simulations. In neo-Darwinian theory of evolution, sympatric speciation has been considered as an improbable and negligible phenomenon just because in the mean field models of very large Mendelian populations (panmictic, with very high intragenomic recombination rate) these effects cannot be observed. Computer modeling also showed that the shrinking of the Y chromosome observed during genome evolution of mammals is connected with promiscuity in the strategy of their reproduction.
Źródło:: Kosmos; 2009, 58, 1-2; 29-41
0023-4249
Pojawia się w:: Kosmos
Dostawca treści:: Biblioteka Nauki

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Tytuł:: ŚREDNIOWIECZNE DOMY NA GARNKACH W ŚWIETLE BADAŃ ARCHEOLOGICZNYCH W NIDZICY
MEDIAEVAL HOUSES ON POTS IN THE LIGHT OF ARCHAEOLOGICAL EXCAVATIONS IN NIDZICA
Autorzy:: Mackiewicz, Hanna Dorota
Powiązania:: https://bibliotekanauki.pl/articles/538204.pdf
Data publikacji:: 2005
Wydawca:: Narodowy Instytut Dziedzictwa
Tematy:: domy na garnkach
Nidzica
badania archeologiczne
stratygrafia
warstwy stratygraficzne
eksploracja
izolacja
Opis:: The expectations associated with the archaeological supervision initiated in September 1999 in the eastern row of houses in the Old Town of Nidzica concerned relics connected with old settlements and town development. Already the exploration of the first metres unearthed strata dating from the Hallstatt D/La Tene A period, associated with the settlement of the western Balt barrow culture and the Przeworsk culture. The significance of this discovery made it possible to change the very nature of the excavation from supervision to archaeological research. The five basic stratigraphic layers distinguished in the course of the investigations include: I level – contemporary and nineteenth-century surfaces, II level – late mediaeval and modern layers, III level – late mediaeval traces of half-timber buildings in the southern row of houses in the market square, IV level – mediaeval strata containing relics of pottery, V level – ancient. The most interesting element registered in the course of the excavations was the longitudinal insulation of the mediaeval buildings made of pots fashioned on a potter’s wheel. A stone pavement on a sand bed, certainly comprising the cellar floor, was found at a depth not exceeding 2 metres. A layer of vessels was discovered after the removal of the pavement. Compactly arranged and turned upside down, the empty pots, covered with clay, provided excellent insulation against dampness and, at the same time, created a stable sleeper for the whole building, as evidenced by the remnants of partition walls built directly on the “pot” insulation. The excavations registered more than 200 whole “insulation” vessels and almost the same number of their fragments. The dendrochronological examination of the wooden construction on the pavement above the insulation was performed by M. Krąpiec, who established the time span of the construction as 1372-1407. In view of the fact that the town’s locatio took place in 1381, we may narrow down the origin of the construction to the post-1381 and pre-1408 period. The described insulation remains unique on a Polish and European scale. The exposition of the findings posed a different problem. Thanks to an agreement between the Voivodeship Conservator of Historical Monuments for Varmia and Mazuria and the museum at Nidzica Castle as well as the assistance of the staff of the Voivodeship Office for the Protection of Historical Monuments in Olsztyn it was possible to recreate a small fragment of this example of mediaeval technology.
Źródło:: Ochrona Zabytków; 2005, 4; 77-84
0029-8247
Pojawia się w:: Ochrona Zabytków
Dostawca treści:: Biblioteka Nauki