Chlorophyll (Chl) fluorescence temperature cinve (FTC) of primary leaves of spring barley (Hordeum vulgare L.), cultivated imder a low irradiance, was studied at low actinic radiation excitation (436 nm, 2 W m'^) under a heating regime consisting of a linear increase of temperature (0.083 °C s’*), followed by a period of constant temperature. After prompt cooling of the sample to 77 K, Chl fluorescence spectra at defined points of the temperature regime were measured. Two distinct temperature and kinetic regions expressed by two discemible temperature maxima were observed for ťhis type of the FTC. Two triggering temperatures of successive irreversible changes are postulated at 45-48 “C and 53-55 °C temperature intervals, respectively; they may correlate with the heat inactivation of photosystem 2 and with changes of the chloroplast and cytoplasmic membrane integrity.
The article aims to introduce and explore the concept of „transculturation". Unlike the affiliated concept of „acculturation", capitalized widely in anthropology, sociology and other branches of social Sciences, the concept of transculturation had until recently commanded little attention outside the limited area of Latin American studies. The concept, originally formulated in the 1940s by Cuban sociologist Fernando Ortiz, accentuates the mutual character of cultural interaction, the active participation of „subordinate" groups in the process, as well as the unique character of the resulting cultural formation. That is,
the processes of enforced cultural exchange (for example, through colonial expansion) are preceived as not only destructive, but also Creative. While the concept of transculturation had commonly been applied within the frame of American or African history and anthropology, the present article proposes the advantages and possibilities of its use in the study of (Central) European millieu - be it in the study of German-Jewish-Czech interaction in the nineteenth century, or in the study of Protestant-Catholic cultural exchange after the year 1620.
Newtonova latinská formulace prvního zákona pohybu je od prvního překladu Principií (A. Mott 1729) až po současnost interpretována ve smyslu zákona setrvačnosti rovnoměrného přímočarého pohybu. Newton však svou formulací prvního zákona ve spojení s komentářem k ní vyjádřil zákon setrvačnosti rovnoměrného pohybu i rotačního. Je to dokázáno na základě Newtonových rukopisů a údajů v Príncípiích. Je navrženo odpovídající správné znění prvního zákona ve fyzikální literatuře a v učebnicích. Těleso setrvává ve svém stavu klidu nebo rovnoměrného pohybu [postupného, rotačního] v daném směru, pokud není působícími silami nuceno tento stav měnit., Newton‘s latin enunciation of the First law of motion is interpreted beginning with the first translation of the Principia till nowadays, in the sense of the law of the uniform rectilinear motion. Newton expressed, however, by his enunciation of the First law in connection with the commentary to it also the law of inertia of the unifom rotatory motion. This is proved on the basis of Newton's manuscripts and of the data given in the Principia. Corresponding correct wording of the First law is proposed to be used in the physical literature and in the textbooks., Martin Černohorský., and Obsahuje seznam literatury
The European hedgehog, Erinaceus europaeus Linnaeus, 1758, is a common host of Ixodes ricinus L. and I. hexago-nus Leach, vectors of the Lyme disease spirochaete, Borrelia burgdorferi sensu iato. To investigate whether hedgehogs are reservoirs for li- burgdorferi, hedgehogs were captured in a suburban area suitable for both tick species and in an urban area where /. ricinus is absent. The infection status of the hedgehogs was determined by xenodiagnosis using I. ricinus and I. hexagonus larvae. /. hexagonus and/or I. ricinus were found on all hedgehogs (n = 8) from the suburban area. In contrast, only I. hexagonus was infesting animals (n = 5) from the urban area. A total of 12/13 hedgehogs harboured B. burgdorferi infected ticks. Xeno-diagnostic I. ricinus and I. hexagonus larvae that fed on hedgehogs became infected. The results clearly show that European hedgehogs are reservoir hosts of the Lyme disease spirochetes. DNA of B. burgdorferi sensu stricto, В. garinii and В. afzelii was detected in culture from ear biopsy and needle aspiration material and characterized by using a genospecies-specific PCR assay. One hedgehog presented a mixed infection of the skin with fi. burgdorferi sensu stricto and fi. garinii. This study also identifies an enzootic transmission cycle in an urban area involving E europaeus and /. hexagonus. The close association of /. hexagonus with the burrows of its hosts mean that the risks of contact between /. hexagonus and humans may be low.
Extrasporogonic stages of Sphaerospora sp. from the kidneys of Atlantic salmon (Salmo salar L.) were successfully transmitted via intra-peritoneal injection to naive Atlantic salmon and brown trout (Salmo trutta L.). Rainbow trout (Oncorhynchus mykiss Walbaum) could not be infected in this way. Transmitted extrasporogonic stages continued their development to form sporogonie stages and mature spores in the kidney tubules. Extrasporogonic stages, sporogonie stages and mature spores of the parasite in both experimentally infected hosts were morphologically identical to the equivalent stage in naturally infected Atlantic salmon, although minor differences were seen in spore dimensions. A farm-based exposure experiment confirmed the susceptibility of brown trout to the salmon Sphaerospora, These results are consistent with the view that the salmon Sphaerospora is Sphaerospora truttae Fischer-Scherl, El-Matbouli et Hoffmann, 1986. The parasite is redescribed according to the guidelines of Lom and Arthur (1989) since details of extrasporogonie stages, the ultrastructure of extrasporogonic and sporogonie stage development, and of the parasite’s epidemiology are known from Atlantic salmon but not from other reports.
The present study is focusing on the transmission of the monogenean ectoparasite Gyrodactylus salaris Malmberg, 1957, a major pathogen on natural populations of Norwegian Atlantic salmon, Salmo salar L. In laboratory experiments the transmission rate of G. salaris after direct host to host contact was positively correlated with water temperature (1.2, 4,7 and 12.2°C). The transmission of detached G. salaris in the planktonie drift was studied in field experiments where salmon parr were individually isolated for 24 hours in small wire mesh cages suspended in the water column. Ten out of 157 salmon parr (prevalence 6.4%, mean intensity 1.0) contracted G. salaris infections after this exposure. Furthermore, 200 uninfected marked salmon parr were released into the same area of the river. After 24 and 48 hours, respectively 18 and 19 marked parr were caught by electro-fishing. The prevalence of G. salaris was 44.4% (mean intensity 1.9) after 24 hours, rising to 57.9% (mean intensity 2.3) after 48 hours. Gyrodactylids have no specific transmission stage or swimming ability, but detached G. salaris drifting in the water column were found to infect salmon parr. However, the transmission rate was markedly higher to free-living fish, suggesting that transmission routes such as indirect transmission from the substrate or direct contact transmission from infected live and/or dead fish, are relatively more important than transmission by drifting detached parasites.
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