In the subcontinental, semiarid lowland region of Central Bohemia (Czech Republic), continuous human impact acting together with diverse natural environmental conditions resulted in the present extraordinarily complex pattern of vegetation. Three radiocarbon-dated pollen diagrams for the area indicate that this complexity results from past vegetation development. During prehistory, places suitable for settlement (with respect to climate, geology, hydrology, etc.) were colonized and transformed first. This resulted in a diachrony in vegetation development due to human activity starting in the first half of the Holocene. This caused an increase in diversity in the region as plant species persisting from previous periods, along with those associated with different agricultural practices, increased. Local abiotic factors affected not only the chronology of human impact but also its specific effects on the ecosystem. Anthropogenic pressure may have had different effects under different conditions. Human population pressure was the mediator between the abiotic diversity and selectively transformed vegetation suitable for the respective habitats. Differences in the chronology of human impact, mixed oak woodland degradation, and the chronology of beech, silver fir and hornbeam expansion are documented for the different ecological zones of the study area. These differences shed light on the mechanisms resulting in some of the important changes in Holocene vegetation. In the absence of man, the decline in mixed oak woodlands, typical of the Middle Holocene in Central Bohemia, would have been probably much slower and less extensive. Unlike in the uplands and mountains, the expansion in the area of beech, silver fir and hornbeam would have been insignificant. The present vegetation resulted to a large extent from management during High Middle Ages. There is almost no continuity in vegetation from the late prehistory to the present.
The paper derives fundamental formulae for calculation of large deformations of circular axisymmetric elastic membranes under uniform pressure and then presents and compares several possible solutions. The thorough study gives reader an opportunity to query the matter in detail and therefore to understand the limitations which can occur during calculations of large deformations of membranes. and Práce detailně odvozuje základní vztahy pro výpočet velkých deformací kruhových axisymetrických elastických membrán zatížených rovnoměrným tlakem a následně představuje a srovnává několik možných řešení. Hloubka studie nabízí čtenáři možnost podrobně nahlédnout do problematiky, a tedy dostatečně porozumět úskalím, která při výpočtech velkých deformací membrán mohou nastat a nastávají.
The paper presents and analyses the Talbot effect - self-imaging of a periodical structure in given distances behind a template, if the template is illuminated by a plane wave. This phenomenon has many applicationsin optical metrology and in industry. The detailed mathematical analysis with an amplitude grating illuminated by a monochromatic plane and spherical wave is performed. Afterwards, the applications in optical metrology, lithography, and measuring displacements are shown and described. and V práci je představen a analyzován Talbotův jev - samozobrazování periodické struktury v určitých vzdálenostech za svou předlohou, je-li tato předloha osvětlena rovinnou vlnou. Tento jev má řadu praktických aplikací v optické metrologii a průmyslu. Je provedena podrobná matematická analýza na příkladu amplitudové mřížky osvětlené monochromatickou rovinnou a sférickou vlnou, a dále jsou představeny a popsány vybrané aplikace využívající tento jev v oblasti optické metrologie, litografie a měření posunů.