17618 research outputs found
During the Czech Antarctic expedition 2014, 102 fish of six species (Trematomus hansoni, T.bernacchii, T. newnesi, Notothenia coriiceps, Parachaenichthys charcoti, Pagothenia borchgrevinki) were examined for parasites. The fish were caught in the Prince Gustav Channel (depth about 5–25 m) off the Johann Gregor Mendel Station on the James Ross Island. Altogether 7,925 metazoan parasites were found, which were identified to individual groups (usually classes). The most abundant were nematode larvae (prevalence 97.0 %, mean abundance 32.7 larvae/per fish), followed by acanthocephalans, especially larvae of species of Corynosoma (76.5%, 14.9) and monogeneans (77.5%, 13.0). Cestodes (Diphyllobothriidea, Tetraphyllidea) were represented by larval stages whereas trematodes only by adults. Our preliminary data may help in future studies on fish parasites in Antarctica because they indicate the most abundant groups of parasites occurring in notothenioid fish
The paper focus sensitivity of an Antarctic lichen Usnea antarctica to photoinhibition studied under controlled laboratory conditions. Main emphasis was given to the analysis of quenching mechanisms, i.e. deexcitation pathways of absorbed light energy exploited in non-photochemical processes. Thalli of U. antarctica were collected at the James Ross Island, Antarctica (57°52´57´´ W, 63°48´02´´ S) and transferred in dry state to the Czech Republic. After rewetting in a laboratory, they were exposed to medium light intensities (300, 600 and 1000 mmol m-2 s-1 of photosynthetically active radiation) for 6 h. Before and during photoinhibitory treatments, chlorophyll fluorescence parameters, photoinhibitory (qI), state 1-2 transition (qT), and energy-dependent quenching (qE) in particular were measured to evaluate dose- and time-dependent changes in these parameters. The results showed that among the components forming non-photochemical quenching (qN), qI contributes to the largest extent to qN, while qE and qT contribute less. This finding differs from our earlier studies made in a short term-, and high light-treated U. antarctica that found qE together with qI is the most important part of non-photochemical quenching. Possible explanation is that photoinhibition in PS II in U. ant-arctica, when induced by low to medium light, activates qE to only limited extend and for a relatively short time (tens of minutes). With prolonged high light treatment lasting several hours, qE tends to be reduced to the values close to zero and qI then forms a major part of qN
The study of Triglochin maritima L. was carried out on the Pomor (western) coast of the White Sea, in the Republic of Karelia (64°22'81"N, 35°93'14"E). Morphological analysis of aboveground and underground parts of the clones was performed on virginal plants. Anatomical analysis of leaf sheaths of the current year shoots, rhizomes and adventitious roots was carried out. The viability of pollen was assessed by determining the relative share of normally developed and malformed pollen grains. The content of heavy metals was determined in the soil, sea water and plant samples. The study was carried out on a model transect in the littoral zone on three test plots representing the lower littoral; the middle and the upper littoral zones. Adaptation to wave and storm impact was manifested in a well-developed system of underground organs. In the lower littoral, underground part surpasses the aboveground vegetative organs in terms of the mass and the formation of mechanical tissues. This allows the plants to anchor stronger in the substrate. Pollen analysis confirmed the adaptability of T. maritima plants to the conditions of the lower littoral by a high percentage of normal and, consequently, fertile pollen, which ensures sexual reproduction of the species. T. maritima can be considered as a Fe hyperaccumulator as the plant accumulates very high levels of Fe (22–34 g kg-1), especially in the lower and middle littoral zones, both in underground and aboveground organs. The ability of T. maritima plants to actively deposit metals was revealed on the basis of the coefficient of biological absorption of metals and makes it possible to suggest potential possibility of using the species in phytoremediation technologies on coastal territories
Karsten Piepjohn, Rolf Stange, Malte Jochmann & Christiaane HübnerLongyearbyen feltbiologiske forening (LoFF), P.O.Box 694, 9171 Longyearbyen, 2012. ISBN 978-82-93009-05-4 (printed), ISBN 978-82-93009-06-1 (pdf), paperback, 36 pages
Floristic check-lists were compiled for the first time for Duvefjorden Bay on Nordaustlandet, Svalbard, based on field work in July 2012 and on data from literature and herbaria. The check-lists include 172 species of lichens and 51 species of vascular plants. Several species rare in Svalbard and in the Arctic were discovered: Candelariella borealis was new to Svalbard. 51 lichen species were newly recorded on Nordaustlandet and 131 lichen species were observed in the Duvefjorden area for the first time. Among lichen species rare in Svalbard and in the Arctic the following can be mentioned: Caloplaca magni-filii, C. nivalis, Lecidea silacea, Phaeophyscia nigricans, Polyblastia gothica, Protothelenella sphinctrinoidella, Rinodina conradii, Stenia geophana, and Tetramelas pulverulentus. Two species of vascular plants, Saxifraga svalbardensis and S. hyperborea, were found new to the Duvefjorden area. The investigated flora is represented mostly by species widespread in Svalbard and in the Arctic. Although Duvefjorden area is situated in the northernmost part of Svalbard, its flora is characterized by relatively high diversity of vascular plants and lichens. Apparently this is due to the influence of the warm North Atlantic Current
The present study propounds the notion-complex of cross-textual reconceptualisation as a cognitive-linguistic output of applying Paul Chilton’s (2013, 2014, 2017) model of Deictic Space Theory (DST) to textual practices drawn from the broad domain of political discourse. The DST model has operated methodologically towards conducting a cognitively oriented political discourse analysis of the two victory speeches produced by Donald Trump and Joseph Biden during the 2020 election for US presidency. As a geometric model, DST has been applied to the two speeches in a way that demonstrated the deictic spatial construction of victory in relation to Trump and Biden as the now-here-real speakers on the three axes of discourse referents, time, and epistemic modality. The data analysis has revealed four significant instantiations of cross-textual reconceptualisation made by Biden of Trump’s deictic space of victory as a contested concept: (i) a “clear” and “convincing” victory, (ii) a peripersonal real victory, (iii) Trump and his voters, and (iv) a now shift from a past Democrat to a future President. All four instantiations have proved the hypothesis that the DST model, while revealing the deictic-spatial conceptualisations of “victory” constituted by each speaker in his speech, may further be extended to disentangle the interesting aspect of how one and the same concept could be reconceptualised across two textual practices produced by speakers with ideologically opposed perspectives.
This study attempted to investigate the persuasive meaning of metadiscourse markers in political speeches to see to what extent and how persuasive discourse is constructed in this genre through metadiscourse practices. To this aim, twenty-six political speeches given by Barack Obama, a former president of the United States, were analyzed using a discourse analytic approach and following Hyland’s (2005ab) interpersonal models of metadiscourse to identify the frequency and persuasive function of interactive and interactional devices used. The findings indicated that the persuasive meaning conveyed by metadiscourse was for the most part context-dependent, which sometimes required the speaker to rely on a combination of devices to organize his discourse, persuade audiences, attract their attention and engage them in arguments. Furthermore, interactional devices were more frequently used than interactive ones, reflecting that engaging audiences in arguments and showing one’s attitude and evaluation towards propositions were more likely to contribute to constructing a persuasive political speech. Findings can be discussed in terms of raising the awareness of second language speakers toward the linguistic and pragmatic conventions of political discourse and how persuasive discourse is constructed through metadiscourse markers.
The present article is based on the analysis of the data gathered in a questionnaire survey conducted in the selected groups of the 1st year students who began studying English at the School of Business Administration in Karviná in the summer semester of the academic year 2015-2016. The goal of the study is to detect students’ needs and requirements concerning their foreign language (FL) study at SBA in Karviná. The data collecting was carried out by distributing questionnaires to respondents and evaluating them. The evaluation of the answers has shown that there exists a discrepancy between students' awareness of what their command of English should be and what their future employers would expect and their lack of motivation