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4652. Chaos alebo poriadok?: Ad Vesmír 80, 313, 2011/6
- Creator:
- Hrabčák, Marek
- Type:
- article, model:article, and TEXT
- Language:
- Czech
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
4653. Chaos lásky v individualizované společnosti podle Ulricha Becka a Elizabeth Beck-Gernsheim
- Creator:
- Vohlídalová, Marta
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Language:
- Czech
- Description:
- Autorka recenza: Marta Vohlídalová
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
4654. Chaotic EEG patterns during recall of stressful memory related to panic attack
- Creator:
- Bob, P., Kukleta, M. , Riečansky, I. , Šusta, M. , Kukumberg , P. , and Jagla, F.
- Type:
- article, model:article, and TEXT
- Subject:
- Memory, Panic disorder, Phobia, Stress, EEG, Lyapunov exponent, and Chaos
- Language:
- English
- Description:
- Chaotic transitions likely emerge in a wide variety of cognitive phenomena and may be linked to specific changes during the development of mental disorders. They represent relatively short periods in the behavior of a system, which are extremely sensitive to very small changes. This increased sensitivity has been suggested to occur also during retrieval of stressful emotional experiences because of their fragmentary, temporally and spatially disorganized character. To test this hypothesis we recorded EEG during retrieval of fearful memories related to panic attack in 7 patients and retrieval of anxiety-related memories in 11 healthy controls. Nonlinear data analysis of EEG records showed a statistically significant increase in degree of chaotic dynamics after retrieval of stressful memories in majority of patients as well as in control subjects. This change correlated with subjective intensity of anxiety induced during the memory retrieval. The data suggest a role of nonlinear changes of neural dynamics in the processing of stressful anxiety-related memories, which may play an important role in the pathophysiology of panic disorder.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
4655. Chapman, G.P., Peat, W.E.: An introduction to the grasses
- Creator:
- Šesták, Z.
- Format:
- Type:
- model:internalpart and TEXT
- Language:
- Multiple languages
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
4656. Character of surrounding habitat determines nest predation in suburban idle fields
- Creator:
- Suvorov, Petr and Šálek, Miroslav
- Type:
- article, model:article, and TEXT
- Subject:
- bird conservation, generalist predator, hen eggs, fragmented patches, and landscaoe heterogeneity urbanization
- Language:
- English
- Description:
- Fragments of idle fields in urbanized zones may attract threatened bird species to nest, but, at the same time, may be favoured by generalist nest predators attracted by food resources abundant in urban areas. Only few studies have analysed effects of nest predation risk in suburban habitat fragments while considering the character of the surrounding landscape. We used artificial nests to examine possible effects of patch size and edge distance, extent of surrounding urbanization, habitat composition and heterogeneity on nest predation risk to ground-nesting birds in idle fields within suburban areas. Nest predation risk varied regardless of patch size. Edge effect appeared only combined with the proportion of particular habitat types in the surrounding landscape. Character of surrounding landscape was strongly influential. In particular, predation risk was positively correlated with proportions of unstable disturbed sites nearby but negatively correlated with proportions of adjacent meadows and forests. From the standpoint of nature conservation and effective support to bird diversity in suburban areas, we highlight the importance of diverse nature-like stands such as meadows or forest fragments.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
4657. Characteristics of chlorophyll fluorescence and membrane-lipid peroxidation during senescence of flag leaf in different cultivars of rice
- Creator:
- Jiao, Demao, Ji, Benhua, and Li, Xia
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- active oxygen, catalase, malonyldialdehyde, Oryza, peroxidase, photoinhibition, photooxidation, photosystem 2, premature ageing, superoxide dismutase, and xanthophyll cycle
- Language:
- Multiple languages
- Description:
- With japonica rice 98-08, indica hybrids Shanyou 63, Gangyou 881, and X07S/Zihui 100, and sub-species hybrid Peiai 64S/9311 as materials, chlorophyll (Chl) content, Chl a fluorescence parameters, and membrane lipid peroxidation in flag leaf were measured at late developmental stages under natural conditions. Fv/Fm, qP, ΦPS2, and electron transport rate gradually decreased while qN increased conversely. Excessive photon energy led to the accumulation of active oxygen (O2-), H2O, malonyldialdehyde, and products of membrane lipid peroxidation, and resulted in reduced Chl content and early ageing subsequent to the photooxidation during flag leaf senescence. There was obvious diversification of these parameters among rice cultivars. In comparison with japonica cv. 98-08 (tolerant to photooxidation), Fv/Fm decreased in indica cv. Shanyou 63 (susceptible to photooxidation) with greater accumulation of active oxygen and a sharp drop in Chl content, which resulted in "yellowish" early ageing, and affected the filling and setting of rice grains. The mechanism for premature ageing in indica rice was related to irradiance and temperature at filling stages. On a sunny day at above 25 °C, the reaction centre of photosystem 2 (PS2) exhibited a dynamic change on reversible inactivation. Under the intense irradiance at noon, PS2 function in indica rice exhibited obvious down-regulation and photoinhibition. Under intense irradiance with lowered temperatures, PS2 resulted in photo-damage and early ageing, related to the degradation of PS2-D1 protein and the inhibition of endogenous protection systems such as the xanthophyll cycle and enzymes scavenging active oxygen. Hence for high-yield breeding, based on a good plant-type and utilising heterosis and tolerance of photooxidation, the selection of japonica rice or a sterile line with the japonica genotype as female is a strategy worthy of consideration. and Demao Jiao, Benhua Ji, Xia Li.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
4658. Characteristics of in vivo nitrate reduction in the CAM plant Notonia grandiflora DC.
- Creator:
- Balakumar, T., Thangavel, M., and Paliwal, K.
- Format:
- Type:
- model:internalpart and TEXT
- Language:
- Multiple languages
- Description:
- Characteristics of in vivo nitráte reductase (NR, EC 1.6.6.1) activity in leaf tissue of the crassulacean acid metabolism (CAM) plant Notonia grandiflora DC. were determined. The pH optimum for the enzyme was 7.0. Among the five low molecular mass solvents tested, n-propanol was more effective in promoting NR activity. Supply of 1.0 % (v/v) M-propanol along with 0.5 % Triton X-100 was the most appropriate assay condition to bring about maximum NR activity (NRA), that was proportionally enhanced with duration of the incubation and mass of the leaf tissue. Leaf fragments of 2 to 4 mm slice width had maximal NRA. The highest NRA was obtained with 200 mM of nitráte supplied in the infiltration medium. NRA was higher in fully expanded, mature leaves than in tender and senescing leaves. The cellular nitráte content was strongly positively correlated with NRA in leaves of various physiological ages. The NRA/N03’ content ratio (index of nitráte utilization efQciency) was the highest for the tender leaves and the lowest for the senescing leaves. However, maximum total titratable acidity (malate production) was obtained for the fully expanded mature leaves in comparison with the other leaves. A positive and significant correlation (r = 0.92) was obtained between nitráte reduction and titratable acid content. The results are indicative of a possible role of nitráte reduction in the regulation of noctumal acid production in the CAM plants.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
4659. Characteristics of photosynthetic apparatus in Mn-starved maize leaves
- Creator:
- Jiang, C.-D., Gao, H.-Y., and Zou, Q.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- chlorophyll fluorescence, net photosynthetic rate, photoinhibition, violaxanthin, violaxanthin de-epoxidase, xanthophyll cycle, Zea, and zeaxanthin
- Language:
- Multiple languages
- Description:
- The effects of Mn-deficiency on CO2 assimilation and excitation energy distribution were studied using Mn-starved maize leaves. Mn-deficiency caused about 70 % loss in the photon-saturated net photosynthetic rate (PN) compared to control leaves. The loss of PN was associated with a strong decrease in the activity of oxygen evolution complex (OEC) and the linear electron transport driven by photosystem 2 (PS2) in Mn-deficienct leaves. The photochemical quenching of PS2 (qP) and the maximum efficiency of PS2 photochemistry (Fv/Fm) decreased significantly in Mn-starved leaves under high irradiance, implicating that serious photoinhibition took place. However, the 'high-energy' fluorescence quenching (qE) decreased, which was associated with xanthophyll cycle. The results showed that the pool of de-epoxidation components of the xanthophyll cycle was lowered markedly owing to Mn deficiency. Linear electron transport driven by PS2 de-creased significantly and was approximately 70 % lower in Mn-deficient leaves than that in control, indicating less trans-thylakoid pH gradient was built in Mn deficient leaves. We suggest that the decrease of non-radiative dissipation depending on xanthophyll cycle in Mn-starved leaves is a result of the deficiency of trans-thylakoid pH gradient. and C. D. Jiang, H. Y. Gao, Q. Zou.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
4660. Characteristics of rare males in the cobitid unisexual comples, Cobitis hankugensis-Iksookimia longicorpa
- Creator:
- Park, Jong-Young, Kim, Ik-Soo, and Ko, Myung-Hun
- Type:
- article and TEXT
- Subject:
- cobitidae, reproduction, gynogenesis, and cell morphology
- Language:
- English
- Description:
- The Cobitis hankugensis-Iksookimia longicorpa (formerly C. sinensis-C. longicorpus) complex in South Korea includes diploid and triploid forms of hybrid origin that are most often females. However, there are a few males that show no differences from the hybrid females in their general morphology except the presence of a lamina circularis on the pectoral fin. An examination of 354 adult hybrid specimens revealed that 3 % of the complex are male specimens. The testes of the rare males are normal in shape and external morphology. The gonadosomatic index of hybrid males is similar to that observed in males of the parental species and changes during the year in a similar pattern. However, the testicular cells differ from those of the parental species in their morphology. Especially sperm cells are very rare and show abnormalities in their morphology, therefore we conclude that the rare males are sterile. This result suggests that although males are present with a low frequency in the complex, this complex functionally is unisexual and depends on the males of the parental species for perpetuation.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/