By an analysis of the Brock’s model tests (Brock, 1969) conditions for forming of roll-waves are determined together with experimental equations of their parameters in relation to the channel inflow wave (Kunštátský, Maleňák, Pejchal, 1967; Kybast, 2002), aeration of flow (Douma, 1943; Haindl, Lískovec, 1973), channel slope and roughness along the whole range of the water flows. Calculations of lower and upper flow roll-waves discharge, depths, velocities, time periods, wave distances and volumes are presented. and Rozborem Brockových modelových zkoušek (Brock, 1969) jsou určeny podmínky tvoření translačních vln a experimentální rovnice jejich parametrů v souvislosti s rázovou vlnou napouštění koryta (Kunštátský, Maleňák, Pejchal, 1967; Kybast, 2002), s provzdušněním proudu (Douma, 1943; Haindl, Lískovec, 1973), sklonem koryta a s jeho drsností v celém rozsahu tohoto proudění vody. Předložen je výpočet dolního proudu a horního proudu s translačními vlnami, jejich průtoků, hloubek a výšek, rychlostí, časových period, vzdáleností a objemů vln.
In this paper, we give necessary and sufficient conditions on $(p_n)$ for $| R,p_n| _k$, $k\ge 1$, to be translative. So we extend the known results of Al-Madi [1] and Cesco $\left[ 4\right] $ to the case $k>1$.
At various intervals after inoculation of the roots of groundnut plants with the fungus Macrophomina phaseoli, 14CO2 was administered to branch 2 (from the base) of the plants in the light. The effects of the disease on the translocation of 14C-photosynthates out of the source branch to the rest of the plant were studied 24 h after labelling. As the plant aged and the disease symptom development became more evident, an increasing percentage of the fixed 14C-photosynthates was exported from branch 2 of the inoculated plants (IP) compared to the non-inoculated plants (NIP). The apex, main stem, and branch 1 of NIP imported more of the total fixed 14C throughout the developmental stages of the plant except for day 10 after inoculation when branch 1 of IP imported almost 76 % of the total fixed 14C. The roots of IP were the major sink and imported higher percent of the total fixed 14C than the roots of NIP.
This paper deals with an effect of a chemical processing and an exposure time to the diffraction efficiency and the signal/noise ratio of diffraction gratings made on silver-halide emulsions Agfa Gevaert. The results of measurements on gratings treated by 14 different chemical processes are presented. and Práce se zabývá vlivem chemického zpracování a osvitu na difrakční účinnost a poměr šumu k signálu u difrakčních mřížek zhotovených do halogeno-stříbrných emulzí Agfa Gevaert. Jsou zde zpracovány výsledky měření na mřížkách zpracovaných 14 různými chemickými procesy.
In the adult fish trematode Crepidostomum metoecus (Braun, 1900), four types of sensory receptors were observed inside the forebody tegument and one type beneath the tegument basal lamina. Two types of sensory receptors extend through the thickness of tegument and have a free cilium inside a pit (types I and II). Two types (III and IV) are nonciliate and entirely intra-tegumental in location. Type IV receptor with large horizontal and thin vertical rootlets was described earlier in aspidogastreans only. Below the basal lamina, nerve endings in close association with muscle fibres, comparable with those in the Aspidogastrea, were detected.
Five types of presumed ciliate sensory receptors were detected in the forebody papillae of the adult fish trematode, Crepidostomum metoecus (Braun, 1900). The cilia are short and submerged in a tegumental pit. The apical bulb part of all types of receptors observed is supported by a dense collar and connected to the tegument basal plasma membrane by a circular septate junction. In sensory receptors types I and III no rootlet is present; the bulbs of sensory receptors types III and IV contain an electron-dense formation.
Transnationalism and diaspora are concepts that are often intertwined but nonetheless differ. This article examines the link between transnationalism and integration processes among return migrants from the Armenian diaspora and examines the role social networks play in integration in Armenia. Returnees to Armenia can be divided into those who have returned from the Armenian diaspora (second and subsequent generations of migrants) and those who emigrated from Armenia and decided to return. This is reflected in the literature as a distinction between the 'old' and the 'new' Armenian diaspora, the latter having emerged in the 1990s. Before returning, both groups maintained ties with people in Armenia and may differ only by the extent and frequency of use of these ties. These ties can then accompany them when they return to Armenia and help them to (re-)integrate. The integration of returnees has its own specifics, compared to the integration of migrants, and may not be as simple as it might seem. This article focuses on the transnational ties of 23 migrants of Armenian descent who returned to Armenia after a long time abroad and draws on original research on return migration in Armenia conducted in 2016 and 2018. Semi-structured interviews with returnees revealed that their participation in the labour market is instrumental to their integration into mainstream society, and their work may involve transnational activities. The article shows the different opportunities that weak and strong ties provide returnees and that may facilitate their integration. Weak ties on a local level are crucial for returnees to be able to reintegrate and fully participate in life in Armenia. The article aims to understand the return strategy as one of the migration options that may or may not be permanent. A return may be followed by re-migration, under certain conditions and if obstacles to sustainable reintegration, and the article also explores the motivations for re-migration.
This article deals with Ukrainian student migration and the convergence of integration and transnationalism. Its main focus is the self-identification of young Ukrainians studying in the Czech Republic. The authors explore and describe international students' different integration and transnational dispositions and also discuss whether these dispositions could be seen as part of antagonistic or synergetic processes. The interconnection between transnationalism and integration is widely discussed in both sociological and anthropological literature, and most scholars identify them as synergetic processes. In the case of Ukrainian students in the Czech Republic, however, the authors argue that these processes can be understood as both synergetic and antagonistic because what matters is the students' self-identification. Most of the analysis presented in this article is based on in-depth interviews with Ukrainian students conducted between 2012 and 2019. The results of qualitative research are also compared to and discussed in relation to the findings from an on-line survey conducted among 258 Ukrainian students in 2018. The article suggests that Ukrainian students themselves could incline in both directions, towards an antagonistic and a synergetic understanding of integration and transnationalism, because it depends on their self-expressed dispositions. However, most participants most of the participants in the research express the synergy.
Transparentní keramika se v laserové technice využívá jako matrice aktivních laserových prostředí vysokovýkonových laserů, kde se začala prosazovat od začátku milénia. Díky svým jedinečným vlastnostem je atraktivní alternativou monokrystalů a skel, kdy nachází využití v široké škále oborů a aplikací zahrnujících optiku, vojenství, medicínu, detektory záření a další., Transparent ceramics have been used as matrices for laser gain media of high power lasers since the beginning of this millennium. Thanks to its unique qualities it has become an attractive alternative to glasses and single crystals, finding applications in the field of optics, defence, medical facilities, radiation detectors and many others., Samuel Paul David, Petr Navrátil, Martin Hanuš, Venkatesan Jambunathan, Martin Divoký, Antonio Lucianetti, Tomáš Mocek., and Obsahuje bibliografické odkazy