A permanent snow cover for several months is typical for large parts of Norway, Sweden and Finland. Snow layers thicker than about 20 cm insulate the soil surface and stabilize the ground temperature close to 0°C. Many ground-living invertebrates are active at this temperature in the subnivean air space. From this "base camp", some invertebrates migrate upwards to use the snow as a substrate. The intranivean fauna consists of springtails (Collembola) and mites (Acari) that are small enough to move within the narrow pores between snow crystals. The supranivean fauna consists of various invertebrates that are active on the snow surface. Some of them are Collembola that have migrated through the snow layers. However, most of them are larger insects and spiders which migrate between the subnivean and supranivean habitats following air channels which are naturally created along tree stems, bushes etc. penetrating the snow. Likewise, certain Chironomidae and Plecoptera, hatching from winter-open rivers and brooks, are active on the snow surface. The supranivean arthropod fauna has the following characteristics: 1. It is a weather dependent assemblage of species, coming and going with changes in air temperature, cloud cover, and wind. Below ca. -6°C animals are absent, but at temperatures around or above zero, many groups can be simultaneously active on snow. 2. The snow surface fauna shows phenological changes throughout the winter, as certain species and groups are mainly active during certain months. 3. Some invertebrates are highly specialized and take advantage of the snow surface as an arena in their life cycle. Examples are Hypogastrura socialis (Collembola), and the two wingless insects Chionea sp. (Diptera: Limoniidae) and Boreus sp. (Mecoptera). They use the smooth snow surface for efficient migration. Chionea sp. and Boreus sp. lay their eggs during the snow-covered period, while H. socialis migrates to create new colonies. The cold tolerant spider Bolephthyphantes index is unique in constructing webs in small depressions on the snow, to catch migrating Collembola. Various adaptations for using the snow as a substrate are discussed. Besides physiological and morphological adaptations, snow surface arthropods show special behavioural adaptations. Most conspicuous is the ability of several Collembola species to navigate during migration, using the position of the sun for orientation. Furthermore, in Collembola and Mecoptera, jumping as an original mechanism to escape predators has independently evolved into a migrating mechanism. An evolutionary potential exists for more invertebrate groups to take advantage of snow as a substrate in their life cycle. For instance, several more cold tolerant spiders might evolve the ability to catch migrating Collembola on snow.
Cestodes of the family Anoplocephalidae Cholodkovsky, 1902, in their adult form, parasitize a variety of hosts, including reptiles, birds and mammals. To complete their life cycle, an intermediate host is required. This study gives a critical review of the life cycles of genera principally important to veterinary medicine (but sporadically infecting man): Anoplocephalinae (Anoplocephala, Anoplocephaloides, Bertiella and Monieziu) and Thysanosomatinae (Avitellina, Stilesia, Thysaniezia and Thysu-nosomu), using data reported by others and our own observations. The accepted paradigm on the biology of the anoplocephalid cestodes is that oribatid mites (Acarina) serve as intermediate hosts. However, as regards the genera Avitellina, Thysaniezia and Thysanosoma, it is still unclear whether oribatid mites are indeed the intermediate hosts, as larval forms (cysticercoids) have also been found in collcmbolans and psocids. Using the controversial biological cycle of Thysanosoma actinioides (Diesing, 1834), a theoretical methodological research proposal for parasitology was constructed which attempts to define a conceptional mark enabling us to predict and explain the parasite-hosts’ related phenomenon. Aspects of this proposal are discussed using the biology of the cestodes of family Anoplocephalidae, as examples.
The aim of this review article is to assess the use of different research methods in empirical studies on the influence of new media on journalism. It analyses all articles related to the topic which were published between 2006 and 2013 in three selected prestigious academic journals - Journalism, Journalism Studies and New Media & Society. Employing the principles of systemic review, the articles are grouped in three temporal categories according to the methods applied in the research they present. It is concluded that mostly traditional research methods were used in the analysed period, only with minor adaptation to the new communication environment. Only from 2009 some tendencies towards a change of classical methods (software analysis, various combinations of methods) and techniques (using of special software which helps to study new internet phenomena such as social networks sites Facebook and Twitter) are evident., Roman Hájek., and Obsahuje seznam literatury
Larvae (metacestodes) of tapeworms of the cyclophyllidean family Gryporhynchidae (previously included in the Dilepididae) occur in different internal organs of fresh- and brackish water fish (110 fish species of 27 families in 12 orders reported), which serve as the second intermediate hosts. The species composition, spectrum of fish hosts, sites of infection, and geographical distribution of gryporhynchids recorded from fish are reviewed here on the basis of literary data and examination of extensive material from helminthological collections. Metacestodes of the following genera have been found in fish: Amirthalingamia Bray, 1974 (1 species), Ascodilepis Guildal, 1960 (1), Cyclustera Fuhrmann, 1901 (4), Dendrouterina Fuhrmann, 1912 (1), Glossocercus Chandler, 1935 (3), Neogryporhynchus Baer et Bona, 1960 (1), Paradilepis Hsü, 1935 (5), Parvitaenia Burt, 1940 (2), and Valipora Linton, 1927 (3). However, most published records concern only three species, namely Neogryporhynchus cheilancristrotus (Wedl, 1855) from the intestinal lumen, Paradilepis scolecina (Rudolphi, 1819) from the liver and mesenteries, and Valipora campylancristrota (Wedl, 1855) from the gall bladder of cyprinids and other fish in the Palaearctic Region. Data on other species as well as reports from other regions are very scarce and almost no information is available from Australia, tropical Asia and South America. A recent study of gryporhynchid metacestodes from Mexico (Scholz and Salgado-Maldonado 2001), which reported 13 species, suggested that they may be more common than indicated by records in the literature. Although only a few cases of pathogenic influence of larvae on fish hosts have been reported, the veterinary importance of gryporhynchids remains to be assessed on the basis of more detailed studies. The data available indicate a strict host and site specificity of some species whereas others occur in a wide spectrum of fish hosts and are not strictly site-specific. Evaluation of Paradilepis larvae from the liver of salmonid fish from British Columbia, Canada, identified as P. simoni Rausch, 1949 by Ching (1982), has shown that they probably belong to two species, P. simoni and P. rugovaginosus Freeman, 1954. Metacestodes of the latter species and those of Cyclustera magna (Baer, 1959) from the intestinal wall of Tilapia zillii (Gervais) from Kenya are reported from fish for the first time.
Some features of the biology and feeding relationships of small waterbugs (Notonectidae, Corixidae, Pleidae, Helotrephidae, Aphelocheiridae) and ripicolous bugs (Gelastocoridae, Ochteridae) are reviewed. Individual families are discussed as predators or as prey of other animals. Special attention is given to characteristics and relationships that affect human beings directly or indirectly. The most important relationships from the economic point of view are: bugs and blood-sucking Diptera, bugs and fish, bugs and some endangered or protected amphibians and water birds. Of less importance is the occasional use of some aquatic bugs as saprobity bioindicators. It seems that the economic importance of these bugs has been underestimated.
Autorka v této přehledové stati představuje relativně nový společenskovědní obor Human-Animal Studies se zaměřením na jeho sociologickou dimenzi. Cílem článku není podrobná kompilace existujících publikací na toto téma, ale syntéza klíčových myšlenek, které stojí v základu sociologického chápání Human-Animal Studies, včetně odkazů na zásadní díla a vybrané webové portály, kde mohou zájemci najít podrobnější informace. Autorka představuje základní východiska a teoretické předpoklady tohoto oboru a zasazuje jej do širšího interdisciplinárního rámce. Poukazuje na různorodost přístupů jak z hlediska teoretického, tak metodologického. Poskytuje základní přehled historického vývoje tohoto oboru a jeho postupného etablování v rámci odborných center, univerzit i vědeckých časopisů. Autorka rovněž přibližuje vybraná témata, kterými se tento komplexní obor dnes zabývá, a v závěru nastiňuje jeho možnou budoucí perspektivu., The author of this review article introduces the relatively new social science field of human-animal studies, focusing on its sociological dimension. Her aim is not a particularized compilation of existing publications on the topic, but a synthesis of the key ideas behind the sociological perspective on human-animal studies. The author includes references to crucial works and selected web portals where one can find more detailed information. She introduces the fundamental premises and theoretic assumptions of the field and contextualizes it in a wider interdisciplinary framework. She presents a variety of theoretical and methodological approaches. She provides an elementary outline of the historical development of this field and its successive establishment within academic centres, universities and scientific journals. The author also introduces selected topics which this complex field examines today and, finally, outlines its possible future prospects., Tereza Vandrovcová., and Seznam literatury
Sphingolipids are a diverse and ubiquitous group of lipids. They are widely distributed in parasites and a number of novel forms have been described. Sphingolipid synthesis has been investigated in the malarial parasite, cestodes, digencans and nematodes. Although there are differences in detail, the synthetic pathways involved are similar to those found in mammals.
The main intent of this paper is to present a review on the application of time series analysis techniques in hydrology and climatology. An overview of various statistical tests for detecting and estimating the hydrologic time series characteristics (i.e., homogeneity, stationarity, trend, periodicity, and persistence) is presented, together with their merits and demerits followed by comprehensive reviews of past studies (both basic and applied), and future research directions. The present review revealed that the climatologic time series of precipitation, air temperature, evapotranspiration and climatic change, and the hydrologic time series of streamflow and surface water quality have received a great deal of attention worldwide. Although the application areas of time series analysis techniques are expanding with growing concerns about climate change and global warming, their application is still very limited in groundwater hydrology as well as for non-traditional hydrologic time series. It is also apparent from this review that the detection of trend and stationarity by parametric and/or nonparametric tests has been a major focus in the past. Multiple comparison tests lack appreciation by the researchers for testing homogeneity in the hydrologic and climatologic time series. Furthermore, most studies have ignored the importance of testing periodicity and persistence in the time series, which are equally important properties of hydrologic and climatologic time series. Based on the comprehensive review, future research needs for time series studies in hydrology and climatology are discussed. and Príspevok prináša prehľad aplikácií techník analýzy časových radov v hydrológii a klimatológii. Uvádza prehľad rôznych štatistických testov na zistenie charakteristík týchto radov (napr. homogenity, stacionarity, trendov, periodicity a perzistencie), spolu s ich prednosťami a nedostatkami. Ďalej je uvedený tiež celkový prehľad uskutočnených štúdií (základných aj aplikovaných) a smery výskumu pre budúcnosť. Súčasný prehľad naznačuje celosvetové sústredenie pozornosti na časové súbory klimatologických dát zrážok, teploty vzduchu, evapotranspirácie a zmien klímy, a tiež hydrologických dát prietokov a kvality povrchových vôd. Aj keď so zvýšením záujmu o zmenu klímy a globálne otepľovanie sa oblasti použitia techník analýzy časových radov rozširujú, ich aplikácie v oblasti hydrológie podzemných vôd a ďalších nie celkom tradičných hydrologických údajov sú veľmi obmedzené. Tento prehľad tiež uvádza, že v minulosti sa vyskytli snahy o sústredenie úsilia na postihnutie trendov a stacionarity radov použitím parametrických a/alebo neparametrických testov. Mnohí výskumníci dostatočne neoceňujú viacnásobné porovnávacie testy (multiple comparison tests) homogenity hydrologických a klimatických časových radov. Okrem toho vo väčšine štúdií sú zanedbané dôležité testy periodicity a perzistencie hydrologických radov. Tieto sú ich rovnako dôležité charakteristiky. Na základe všeobecného prehľadu príspevok tiež pojednáva o potrebe ďalšieho výskumu časových radov v hydrológii a klimatológii.
Background - There is growing interest in the role of microbial agents in the causation of psychiatric disorders. The neurotropic protozoan parasite Toxoplasma gondii is one of the main candidates and has been associated with various psychiatric conditions, including schizophrenia. Methods - A narrative review of the literature from the main medical databases (Medline, PubMed, PsycINFO), Google Scholar and Google using combinations of applicable terms. Results - T. gondii affects the brain in both the acute and the latent stages of infection causing apparent brain pathologies in infected rodents and both immuno-compromised and immuno-competent humans. In immuno-competent individuals, behavioural disorders are primarily related to the latent stages of the illness. Behavioural/mental disorders that include schizophrenia, mood disorders, personality changes and cognitive impairments may be related to infection with T. gondii. Evidence for a behavioural effect of T. gondii comes from observational reports in animal models and controlled behavioural analysis in humans. Indirect clues of infection also come from raised seroprevalence or serotitres of antitoxoplasma antibodies among those with mental disorders. The pathophysiologic mechanism through which T. gondii may exert its effect is not clear, but direct impact on the brain and changes in neuroimmunomodulation, neurotransmission and some gene-environment interactions are postulated. Conclusion - There is evidence supporting a potential role of T. gondii infection in the onset of some behavioural disorders. Confirmation of such a role would prove a significant breakthrough in the search for the aetiology, treatment and prevention of behavioural disorders, such as schizophrenia. However, the associations remain preliminary.