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18572. Non-radiative dissipation of absorbed excitation energy within photosynthetic apparatus of higher plants
- Creator:
- Štroch, M., Špunda, V., and Kurasová, I.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- carotenoids, non-photochemical fluorescence quenching, non-radiative dissipation, photoinhibition, photoprotection, photosynthesis, and xanthophyll cycle
- Language:
- Multiple languages
- Description:
- The review deals with thermal dissipation of absorbed excitation energy within pigment-protein complexes of thylakoid membranes in higher plants. We focus on the de-excitation regulatory processes within photosystem 2 (PS2) that can be monitored as non-photochemical quenching of chlorophyll (Chl) a fluorescence consisting of three components known as energy-dependent quenching (qE), state-transition quenching (qT), and photoinhibitory quenching (qI). We summarize the role of thylakoid lumen pH, xanthophylls, and PS2 proteins in qE mechanism. Further, both the similarity between qE and qI and specific features of qI are described. The other routes of thermal energy dissipation are also mentioned, that is dissipation within photosystem 1 and dissipation through the triplet Chl pathway. The significance of the individual de-excitation processes in protection against photo-oxidative damage to the photosynthetic apparatus under excess photon supply is stretched. and M. Štroch, V. Špunda, I. Kurasová.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
18573. Non-response in probability sample surveys in the Czech Republic
- Creator:
- Krejčí, Jindřich
- Format:
- Type:
- model:internalpart and TEXT
- Subject:
- survey research in the Czech Republic, response rates, non-response trends, and fieldwork strategy
- Language:
- Czech
- Description:
- In this article the problem of survey non-response is examined with special reference to probability sampling in the Czech Republic. Non-response rates among Czech respondents in ISSP surveys between 1995 and 2005 were almost twice the rate recorded between 1991 and 1995 (25%). Such trends point to a decline in the 'survey climate'. While non-contacts and refusals in surveys are a significant problem, issues relating to how fieldwork is undertaken are equally important. The large fluctuations in non-contact rates and the relative success of the Czech Statistical Office in attenuating non-response rates demonstrates that prudent surveying strategies can be effective. An examination of two waves of the European Social Survey (ESS) reveals both the problems and potential strategies available for response rate enhancement. In this respect, all survey designers face the dilemma of balancing the benefits of data accuracy with increasing logistical costs. Improvement in survey quality necessitates consideration of many issues and the ability to make sensible trade-offs between competing research objectives.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
18574. Non-stationary departure process in a batch-arrival queue with finite buffer capacity and threshold-type control mechanism
- Creator:
- Kempa, Wojciech M. and Kurzyk, Dariusz
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- transient state, departure process, finite-buffer queue, N-policy, power saving, and wireless sensor network (WSN)
- Language:
- English
- Description:
- Non-stationary behavior of departure process in a finite-buffer MX/G/1/K-type queueing model with batch arrivals, in which a threshold-type waking up N-policy is implemented, is studied. According to this policy, after each idle time a new busy period is being started with the Nth message occurrence, where the threshold value N is fixed. Using the analytical approach based on the idea of an embedded Markov chain, integral equations, continuous total probability law, renewal theory and linear algebra, a compact-form representation for the mixed double transform (probability generating function of the Laplace transform) of the probability distribution of the number of messages completely served up to fixed time t is obtained. The considered queueing system has potential applications in modeling nodes of wireless sensor networks (WSNs) with battery saving mechanism based on threshold-type waking up of the radio. An illustrating simulational and numerical study is attached.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
18575. Non-surjective linear transformations of tropical matrices preserving the cyclicity index
- Creator:
- Guterman, Alexander, Kreines, Elena, and Vlasov, Alexander
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- tropical linear algebra, cyclicity index, and linear transformations
- Language:
- English
- Description:
- The cyclicity index of a matrix is the cyclicity index of its critical subgraph, namely, the subgraph of the adjacency graph which consists of all cycles of the maximal average weight. The cyclicity index of a graph is the least common multiple of the cyclicity indices of all its maximal strongly connected subgraphs, and the cyclicity index of a strongly connected graph is the least common divisor of the lengths of its (directed) cycles. In this paper we obtain the characterization of linear, possibly non-surjective, transformations of tropical matrices preserving the cyclicity index. It appears that non-bijective maps with these properties exist and all maps are exhausted by transposition, renumbering of vertices, Hadamard multiplication with a matrix of a certain special structure, and certain diagonal transformation. Moreover, only diagonal transformation can be non-bijective.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
18576. Non-woven PGA/PVA fibrous mesh as an appropriate scaffold for chondrocyte proliferation
- Creator:
- Michala Rampichová, Eva Košťáková, Elena Filová, Eva Prosecká, Martin Plencner, Ocheretná, L., Lytvynets, A., David Lukáš, and Evžen Amler
- Format:
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, chondrocyty, tkáňové inženýrství, chondrocytes, tissue engineering, PGA, PVA, non-woven textile, 14, and 612
- Language:
- English
- Description:
- Non-woven textile mesh from polyglycolic acid (PGA) was found as a proper material for chondrocyte adhesion but worse for their proliferation. Neither hyaluronic acid nor chitosan nor polyvinyl alcohol (PVA) increased chondrocyte adhesion. However, chondrocyte proliferation suffered from acidic byproducts of PGA degradation. However, the addition of PVA and/or chitosan into a wet-laid non-woven textile mesh from PGA improved chondrocyte proliferation seeded in vitro on the PGA-based composite scaffold namely due to a diminished acidification of their microenvironment. This PVA/PGA composite mesh used in combination with a proper hydrogel minimized the negative effect of PGA degradation without dropping positive parameters of the PGA wet-laid non-woven textile mesh. In fact, presence of PVA and/or chitosan in the PGA-based wet-laid non-woven textile mesh even advanced the PGA-based wet-laid non-woven textile mesh for chondrocyte seeding and artificial cartilage production due to a positive effect of PVA in such a scaffold on chondrocyte proliferation., M. Rampichová ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
18577. Nondestructive determination of nitrogen and chlorophyll content in olive tree leaves and the relation with photosynthesis and fluorescence parameters
- Creator:
- Boussadia, O., Steppe, K., Zgallai, H., Ben el Hadj, S., Braham, M., Lemeur, R., and Van Labeke, M. C.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, electron flow, nitrogen deficiency, olive tree, photosynthesis, pigments, SPAD-502, and quantum yield
- Language:
- Multiple languages
- Description:
- For Tunisian olive tree orchards, nitrogen deficiency is an important nutritional problem, in addition to the availability of water. Establishment of relationships between nutrients such as nitrogen and ecophysiological parameters is a promising method to manage fertilisation at orchard level. Therefore, a nitrogen stress experiment with one-year-old olive trees (Olea europaea L. 'Koroneiki' and 'Meski') was conducted with trees respectively subjected to four nitrogen supply regimes (23.96 meq l-1, 9.58 meq l-1, 4.79 meq l-1 and 0 meq l-1 NO3-). The current paper focuses on the use of the SPAD-502 portable chlorophyll (Chl) meter, a nondestructive method for fertilisation management under nitrogen stress conditions of olive trees. Maximum net photosynthetic assimilation rates, chlorophyll fluorescence parameters and the SPAD Chl index were therefore measured simultaneously and the Chl and nitrogen content of the leaves were analysed. Significant correlations were established in the olive tree leaves between SPAD-502 readings on the one hand and Chl content, nitrogen content, photosynthetic assimilation rate, and Chl fluorescence parameters (ΦPSII and ETR) on the other hand. and O. Boussadia ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
18578. Nondestructive leaf-area estimation and validation for green pepper (Capsicum annuum L.) grown under different stress conditions
- Creator:
- Cemek, B., Unlukara, A., and Kurunc, A.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, green pepper, irrigation regime, irrigation water salinity, leaf area estimation, and nondestructive metods
- Language:
- Multiple languages
- Description:
- Leaf area of a plant is essential to understand the interaction between plant growth and environment. This useful variable can be determined by using direct (some expensive instruments) and indirect (prediction models) methods. Leaf area of a plant can be predicted by accurate and simple leaf area models without damaging the plant, thus, provide researchers with many advantages in horticultural experiments. Several leaf-area prediction models have been produced for some plant species in optimum conditions, but not for a plant grown under stress conditions. This study was conducted to develop leaf area estimation models by using linear measurements such as lamina length and width by multiple regression analysis for green pepper grown under different stress conditions. For this purpose, two experiments were conducted in a greenhouse. The first experiment focused to determine leaf area of green pepper grown under six different levels of irrigation water salinity (0.65, 2.0, 3.0, 4.0, 5.0, and 7.0 dS m-1) and the other under four different irrigation regime (amount of applied water was 1.43, 1.0, 0.75, and 0.50 times of required water). In addition to general models for each experiment, prediction models of green pepper for each treatment of irrigation water salinity and of irrigation regime experiments were obtained. Validations of the models for both experiments were realized by using the measurements belong to leaf samples allocated for validation purposes. As a result, the determined equations can simply and readily be used in prediction of leaf area of green pepper grown under salinity and water stress conditions. The use of such models enable researchers to measure leaf area on the same plants during the plant growth period and, at the same time, may reduce variability in experiments. and B. Cemek ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
18579. Nondestructive, simple, and accurate model for estimation of the individual leaf area of som (Persea bombycina)
- Creator:
- Chattopadhyay, S., Tikader, A., and Das, N. K.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, leaf area prediction, leaf length, leaf width, nondestructive methods, regression model, and validation
- Language:
- Multiple languages
- Description:
- Nondestructive approach of modeling leaf area could be useful for plant growth estimation especially when number of available plants is limited and/or experiment demands repeated estimation of leaf area over a time scale. A total of 1,280 leaves were selected randomly from eight different morphotypes of som (Persea bombycina) established at randomized complete block design under recommended cultural regimes in field. Maximum leaf laminar width (B), length (L) and their squares B2, L2; leaf area (LA), and lamina length × width (L×B) were determined over two successive seasons. Leaf parameters were significantly affected by morphotypes; but seasons had nonsignificant impacts on tested features. Therefore, pooled seasonal morphotype means of each parameter were used to establish relationship with LA. L and its square L2 did not provide accurate models for LA predictions. Considerably better models were obtained by using B (y = 2.984 + 7.9664 x, R2 = 0.615, P≥0.001, n = 119) and B2 (y = 12.784+ 0.9604 x, R2 = 0.605, P≥0.001, n = 119) as independent variables. However, maximum accuracy of prediction of LA could be achieved through a simple linear relationship of L×B (y = 8.2203 + 0.4224 x, R2 = 0.843, P≥0.0001, n = 119). The model (LA:L×B) was validated with randomly selected leaf samples (n = 360) of som morphotypes and highly significant (P≤0.001) linear function was found between actual and predicted LAs. Therefore, the last model may consider adequate to predict leaf area of all cultivars of som with sufficient fidelity. and S. Chattopadhyay ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
18580. Noninvasive arterial compliance estimation
- Creator:
- Švec, David and Javorka, Michal
- Format:
- počítač and online zdroj
- Type:
- model:article and TEXT
- Subject:
- arterial compliance, arterial stiffness, windkessel model, pulse wave velocity, and arterial blood pressure
- Language:
- English
- Description:
- Arterial compliance is an important cardiovascular parameter characterizing mechanical and structural properties of arteries and significantly influencing ventricular-arterial coupling. Decreased arterial compliance is associated with several physiological states and pathological processes. Furthermore, arterial compliance is influenced by other cardiovascular parameters even at short time scales. Today, there are numerous noninvasive methods of estimation arterial compliance in vivo introducing some level of confusion about selection of the best method for particular application and measurement setting. In this review, the most common noninvasive methods of arterial compliance estimation are summarized, discussed and categorized. Finally, interpretation of estimated arterial compliance in the context of other possible confounders is discussed.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public