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574872. Structural analysis within the Rožná and Olší uranium deposits (Strážek Moldanubicum) for the estimation of deformation and stress conditions of underground gas storage
- Creator:
- Jiří Ptáček, Rostislav Melichar, Antonín Hájek, Petr Koníček, Kamil Souček, Staš, Lubomír, Kříž, Petr, and Lazárek, Josef
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, strukturní analýza, deformace, structural analysis, deformations (mechanics), stress, underground gas storage, 7, and 551
- Language:
- English
- Description:
- Uranium deposits, between which gas storage are being designed, the Rožná deposit and Olší deposit, are situated on the east edge of the Strážek Moldanubicum in Bohemian Masiff. Based on structural analysis it was possible to carry out the first rough prediction of potential weak zones in the rock mass. The structural analysis was also one of the supporting materials for determining the geometry and design method for the mine workings for the gas storage and for the advancing exploration of the gas storage region. Until now, the measurement of foliation planes and discontinuity planes in the survey crosscut V1-XXI and in a survey connecting gate GR1-XXI has been carried out. The results of interpretation of the measurement and monitoring of ductile elements (foliations) and joints (ruptures) as well as dislocations interpretation from the mine maps can be summarized and quoted in the contribution., Jiří Ptáček, Rostislav Melichar, Antonín Hájek, Petr Koníček, Kamil Souček, Lubomír Staš, Petr Kříž and Josef Lazárek., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
574873. Structural and ecophysiological plasticity of some evergreen species of the mediterranean maquis in response to climate
- Creator:
- Gratani, L.
- Format:
- Type:
- model:internalpart and TEXT
- Subject:
- Arbutus unedo L., Cistus incanus L., leaf area index, leaf thickness, net photosynthetic rate, Phillyrea latifolia L., Pistacia lentiscus L,, Quercus ilex L., stomatal conductance, and transpiration
- Language:
- Multiple languages
- Description:
- The most representative evergreen shrub species growing in the low mediterranean maquis modified their leaf characteristics during the year, but the response to climate varied among the species. The reál sclerophyllous species, Quercus ilex L., Phillyrea latifolia and Pistacia lentiscus, showed a convergence in higher leaf thickness and lower net photosynthetic rate (P^) compared with Arhuíus unedo L. and Cistus incanus L. Under summer stress they maintained a substantial positive carbon balance. Pistacia was one of the most tolerant species to the drought, it maintained a substantial positive balance over a wide range in temperature. Arhutus and Cistus had relatively thin leaves with a higher succulence index and higher ihe more characteristic sclerophyllous species. The superiority of Cistus in carbon uptake over all the spacies was maintained throughout most of the year by its morphological leaf properties: low leaf thickness, high chlorophyll contents. Besides, Cistus shed most of its leaves before summer, thus reducing its evaporative surface.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
574874. Structural and functional changes in the photosynthetic apparatus of Chlamydomonas reinhardtii during nitrogen deprivation and replenishment
- Creator:
- Preininger, É., Kósa, A., Lőrincz, ZS., Nyitrai, P., Simon, J., Böddi, B., Keresztes, Á., and Gyurján, I.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, electron microscopy, nitrogen starvation, O2 evolution, 77K fluorescence, 2, and 581
- Language:
- Multiple languages
- Description:
- Nitrogen is an essential factor for normal plant and algal development. As a component of nucleic acids, proteins, and chlorophyll (Chl) molecules, it has a crucial role in the organization of a functioning photosynthetic apparatus. Our aim was to study the effects of nitrogen starvation in cultures of the unicellular green alga, Chlamydomonas reinhardtii, maintained on nitrogen-free, and then on nitrogen-containing medium. During the three-week-long degreening process, considerable changes were observed in the Chl content, the ratio of Chl-protein complexes, and photosynthetic activity of the cultures as well as in the ultrastructure of single chloroplasts. The regreening process was much faster then the degradation; total greening of the cells occurred within four days. The rate of regeneration depended on the nitrogen content. At least 50% of the normal nitrogen content of Tris-Acetate-Phosphate (TAP) medium was required in the medium for the complete regreening of the cells and regeneration of chloroplasts., É. Preininger, A. Kósa, Z. S. Lőrincz, P. Nyitrai, J. Simon, B. Böddi, Á. Keresztes, I. Gyurján., and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
574875. Structural and functional damage caused by boron deficiency in sunflower leaves
- Creator:
- El-Shintinawy, F.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- chlorophyll, dry mass of roots and shoots, fluorescence, Hill reaction, lipoxygenase, malondialdehyde, peroxidase, photosystem 2, potassium, and saccharose
- Language:
- Multiple languages
- Description:
- Boron deficiency induced a dramatic inhibition in sunflower plant growth, shown by a reduction in dry mass of roots and shoots of plants grown for 10 d in nutrient solution supplied with 0.02 µM B. This low B supply facilitated the appearance of brown purple pigmentation on the plant leaves over the entire growth period. Compared to B-sufficient (BS) leaves, leakage from B-deficient (BD) leaves was 20 fold higher for potassium, 38 fold for sucrose, and 6 fold for phenolic compounds. High level of membrane peroxidation was detected by measuring peroxidase activities as well as peroxidative products in BD sunflower plants. Soluble and bound peroxidase activities measured in BD thylakoid membranes were accelerated two fold compared to those detected in BS-membranes. No detectable change in soluble peroxidase activity in roots whereas a 4 fold stimulation in bound peroxidase activity was detected. Thylakoid membranes subjected to low B supply showed enhancement in lipoxygenase activity and malondialdehyde (MDA) content in parallel with 40 and 30 % decrease of linoleic and linolenic acid contents (related to total unsaturated fatty acids). A slower rate of Hill reaction activity (40 %) and a suppressed flow of electron transfer of the whole chain (30 %) were detected in BD thylakoid membranes. This reduction was accompanied with a decline in the activity of photosystem 2 shown by a diminished rate of oxygen evolution (42 %) coupled with a quenching (27.5 %) in chlorophyll a fluorescence emission spectra at 685 nm (F685). Thus B is an important element for membrane maintenance, protection, and function by minimizing or limiting production of free oxygen radicals in thylakoid membranes of sunflower leaves.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
574876. Structural and functional organization of the photosynthetic apparatus in halophytes with different strategies of salt tolerance
- Creator:
- Rozentsvet, O. A., Bogdanova, E. S., Ivanova, L. A., Ivanov, L. A., Tabalenkova, G. N., Zakhozhiy, I. G., and Nesterov, V. N.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, water content, salt stress, chlorophyll fluorescence, mesostructure, photoinhibition, 2, and 581
- Language:
- Multiple languages
- Description:
- The specific features of the structural and functional organisation of the photosynthetic apparatus (PSA) were studied in wild halophytes representing three strategies of salt tolerance: euhalophyte Salicornia perennans, crynohalophyte Limonium gmelinii, and glycohalophyte Artemisia santonica. The sodium content in aboveground parts of the plants corresponded to the strategy of salt tolerance. The photosynthetic cells of the euhalophyte were large and contained a higher number of chloroplasts than those in other species. In contrast, the number of cells per a leaf area unit was lower in S. perennans as compared to cryno- and glycohalophytes. Thereupon, the cell and chloroplast surface area per leaf area unit declined in the following sequence: A. santonica > L. gmelinii > S. perennans. However, the large cells of euhalophyte contained chloroplasts of larger sizes with 4- to 5-fold higher chlorophyll (Chl) content per chloroplast and Chl concentration in chloroplast volume unit. Also, chloroplasts of S. perennans were characterised by the higher content of glyco- and phospholipids. Qualitative composition of fatty acids (FA) in lipids isolated from the chloroplast-enriched fraction was similar in all three species; however, the index of unsaturation of FA was higher in glycohalophyte A. santonica than those in two other species. Under natural condition, PSA of all three halophytes showed high resistance to soil salinity. The results indicated tolerance of PSII to the photodamage in halophytes. The high rate of electron transport through PSII can be important to prevent oxidative damage of PSA in halophytes under strong light and hight temperature in vivo. Thus, the strategy of salt tolerance is provided by both the leaf anatomical structure and the ultrastructure of photosynthetic membranes, which is determined in particular by the specific composition of lipids., O. A. Rozentsvet, E. S. Bogdanova, L. A. Ivanova, L. A. Ivanov, G. N. Tabalenkova, I. G. Zakhozhiy, V. N. Nesterov., and Seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
574877. Structural and stress analysis in mining practice in the Upper Silesian Coal Basin
- Creator:
- Petr Waclawik, Jiří Ptáček, and Radomír Grygar
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, strukturní analýza, důlní chodby, těžba uhlí, structural analysis, mine roadways, coal mining, horizontal stress, mine roadway stability, rock burst, 7, and 551
- Language:
- English
- Description:
- The irregular distribution of stress in rock mass is a decisive factor for the origin of rock bursts. Besides, a sound knowledge of stress distribution is very important in the excavation of mine workings. Stress state is affected both by natural stress, including the gravitational, tectonic, hydraulic and residual stress and the stress induced by mining operations. Natural stress fields are defined by their geological structure and rock properties. It is important in mining practice to understand that there is a close relationship between recent and residual tectonic stress, as defined by tectonic evolution and tectonic structure. Since 1994, a large number of horizontal stress measurements have been carried out at a depth of 600 m to 800 m under the surface. The application of the results obtained from the measurements of stress and their comparison with the results of structural analysis and their generalization for the Karviná subbasin can be an important contribution to optimize the timespace designs of the mining activity., Petr Waclawik, Jiří Ptáček and Radomír Grygar., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
574878. Structural breaks in dependent, heteroscedastic, and extremal panel data
- Creator:
- Maciak, Matúš, Peštová, Barbora, and Pešta, Michal
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- panel data, dependence within panels, dependence between panels, changepoint, short panels, heteroscedasticity,, ratio type statistics, and consistency
- Language:
- English
- Description:
- New statistical procedures for a change in means problem within a very general panel data structure are proposed. Unlike classical inference tools used for the changepoint problem in the panel data framework, we allow for mutually dependent panels, unequal variances across the panels, and possibly an extremely short follow up period. Two competitive ratio type test statistics are introduced and their asymptotic properties are derived for a large number of available panels. The proposed tests are proved to be consistent and their empirical properties are investigated in an extensive simulation study. The suggested testing approaches are also applied to a real data problem.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
574879. Structural changes in the economies of the european socialist countries after the second world war :
- Type:
- text and sborníky konferenční
- Subject:
- Ekonomie, sborníky konferenční, struktura hospodářská, státy socialistické, hospodářské dějiny, and světové dějiny od r. 1945 do současnosti
- Language:
- English
- Rights:
- unknown
574880. Structural characteristics of extra-membrane domains and guanidine hydrochloride-induced denaturation of photosystem 2 core antenna complexes CP43 and CP47
- Creator:
- Qu, Y.-G., Gong, Y.-D., Guo, S.-K., Li, L.-B., and Kuang, T.-Y.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- aromatic amino acid, chlorophyll, circular dichronism, CP43, CP47, denaturation, energy transfer, extramembrane domain, fluorescence, guanidine hydrochloride, and β-carotene
- Language:
- Multiple languages
- Description:
- The structural characteristics of the extra-membrane domains and guanidine hydrochloride-induced denaturation of photosystem 2 (PS2) core antenna complexes CP43 and CP47 were investigated using fluorescence emission and circular dichroism (CD) spectra. The extra-membrane domains of CP43 and CP47 possessed a certain degree of secondary and tertiary structure and not a complete random coil conformation. The tertiary structure and the chlorophyll (Chl) a microenvironment of CP47 were more sensitive to guanidine hydrochloride (GuHCl) than that of CP43. Changes in energy transfer from β-carotene to Chl a corresponded well to changes in the tertiary structure while their correlation with changes in the secondary structure was rather poor. Unlike most of water-soluble proteins, both CP43 and CP47 are partly resistant to denaturation induced by guanidine hydrochloride (GuHCl); the denaturation of CP43 or CP47 is not a two-state process. Those features most probably reflect their character as intrinsic membrane proteins. and Y.-G. Qu ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public