The paper approaches problem of the flow forecasting for the Liptovska Mara reservoir with a hybrid modelling approach. The nonlinear hybrid modelling framework was investigated under the specific physiographic conditions of the High Core Mountains of Slovakia. The mean monthly flows of rivers used in this study are predominantly fed by snowmelt in the spring and convective precipitation in the summer. Therefore, their hydrological regime exhibits at least two clear seasonal patterns, which provide an intuitive justification for the application of nonlinear regime-switching time series models. Differences in the prevailing geology, orientation of slopes and their exposure to atmospheric circulation for the right and left-sided tributaries of the Vah River indicate that the hydrological regime of mean monthly discharge time series in this area with respect to seasonality and cyclicity may differ, too. Therefore, a simple deterministic water balance scheme was set up for estimating the reservoir inflow from the left and right-sided tributary flows separately. It consists of the linear combination of the measured tributary flows and estimated ungauged tributary flows. The contributions of the ungauged catchments were estimated from flows from gauged tributaries with similar physiographic conditions by weighting these by the ratio of the catchment areas. Separate nonlinear regime-switching time series models were identified for each gauged tributary. The forecasts of the tributaries were combined into a hybrid forecasting model by the water balance model. The performance of the combined forecast, which could better include the specific regime of the time series of tributaries, was compared with the single forecast of the overall reservoir inflow in several combinations. and V štúdii sme porovnávali kvalitu predpovede viacerých lineárnych a nelineárnych modelov časových radov pri predpovedaní prítokov do nádrže Liptovská Mara. Testovali sme výkonnosť modelov ARMA, SETAR na samotnej rieke Váh a v kombinácii jej prítokov do nádrže Liptovská Mara. Ďalej bol uplatnený jednoduchý deterministický model vodnej bilancie pre prítok do nádrže, ktorý pozostáva z lineárnej kombinácie meraných prietokov prítokov Váhu vážených plochou subpovodia. Výber analogónov sa vykonal vzhľadom na podobnosť fyzicko-geografických podmienok v meraných a nemeraných subpovodiach. Modely typu ARMA a SETAR boli zostavené pre každý prítok osobitne a predpovede prietokov na prítokoch boli skombinované modelom vodnej bilancie a do predpovede celkového prítoku do nádrže. Kombinovanú hybridnú predpoveď (stochasticko-deterministická), zachovávajúcu špecifický režim prítokov a vodnej bilancie v povodiach, sme porovnali s predpoveďou celkového prítoku do nádrže získanou pomocou modelov identifikovaných na hlavnom toku.
Mean leaf inclination of the arctic and alpine shrub Dryas octopetala is a function of latitude and this functional relationship is consistent with a model that maximizes photosynthesis of the total plant canopy.
The Northern pine processionary moth, Thaumetopoea pinivora (Treitschke, 1834) shows a highly scattered distribution with fragmented populations across Europe. A previous study exploring the postglacial history of T. pinivora defined it as a cold-tolerant relict species and concluded that a progressive reduction of suitable habitats after the postglacial expansion from refugia in the southern Iberian peninsula best explained the distribution and genetic structure of populations of this species. However, recent records, both by us and others, challenge this view. Surprisingly, some of the newly found populations from southern Spain use black pine, Pinus nigra J.F. Arnold as a host plant despite the fact that the typical host of the species, Scots pine, Pinus sylvestris L. occurs in the area. We provide genetic data for one of these recently found southern populations where the larvae feed on P. nigra, and compare this with previously published data on individuals collected on P. sylvestris. This data reveals that populations from different host trees are no more genetically differentiated than populations sharing the same host plant. The findings of a wider diet breadth open the way to widen the search for the still unidentified glacial refugium of T. pinivora, and as such may contribute to a better understanding about how the species has spread across Europe., José A. Hódar, Anna Cassel-Lundhagen, Andrea Battisti, Stig Larsson., and Obsahuje bibliografii
In CO2-free air, the CO2 postirradiation burst (PIB) in wheat leaves was measured with an IRGA in an open gas exchange system to ascertain its potential role in alleviating photoinhibition of photorespiratory carbon oxidation (PCO) under a CO2 deficiency. A pre-photosynthesized leaf having been transferred into CO2-free air exhibited a typical CO2 PIB following darkening which could last, with a rate substantially higher than that of dark respiration, over a long time period (at least more than 2 h) of continuously alternate irradiation (2 min)-dark (2 min)-light transitions. The rate and the time of PIB maintenance, although unaffected by the exogenous dark respiration inhibitor iodoacetic acid, were stimulated largely by increasing irradiance and O2 level, and suppressed by DCMU and N-ethyl-maleimide (NEM). They also showed a large photosynthates-loading dependence. In a darkened leaf, the irradiation-induced PIB in the CO2-free air was clearly revealed and it was characterized by an initial net uptake of respiratory CO2. The light-induced PIB was accelerated by increasing irradiance, and delayed by prolonging the period of darkening the leaves. Hence, the origin of carbon needed for a long-term CO2 evolution in the CO2-free air might not only be derived directly from the pool of intermediates in the Calvin cycle, but it might also arise indirectly from a remotely fixed reserve of photosynthates in the leaf via a PCO-mediated, yet to be further clarified, mobilization process. Such mobilization of photosynthates probably exerted an important role in coordination of photochemical reactions and carbon assimilation during photosynthesis in C3 plants under the photoinhibitory conditions. and Fusheng Xiong, Yuzhu Gao, Ping Song.
Field-grown plants of spring barley (Hordeum vulgare L. cv. Akcent) in the growth phase 30 DC (beginning of stem extension) were exposed to a one-shot application of a commercial product containing cyanazine (Bladex 50 SC) in two doses, C30 and C60 (30 and 60 mg m-2). The reaction of the plant photosynthetic system was followed non-destructively using chlorophyll fluorescence induction (the O-J-I-P transient) within three weeks after the application in the fifth developed leaf and three further gradually appearing leaves. An immediate response of plants to the application of cyanazine and a regeneration of plants from cyanazine action were detected. The biological (plant dry mass) and crop yield production (the number and mass of grains in a spike) were analyzed in time of full ripeness. The crop yield was lowered by the herbicide effect to the same level for the two doses used. and M. Matoušková, J. Nauš, M. Flašarová.
Iron is an essential limiting factor for primary production in many marine systems. The present study investigated differential regulation of protein expression in marine phytoplankton Prymnesium parvum under low Fe concentration. The phytoplankton was grown in f/2 culture medium in artificial seawater with low (0.0025 μM) and high (0.05 μM) Fe concentrations. Two-dimensional differential gel electrophoresis and matrix-assisted laser desorption-ionization-time of flight-mass spectrometer analysis were performed for protein identification and characterization. The growth of the alga declined substantially under the low Fe compared to the high Fe concentration. Under low Fe conditions, P. parvum upregulated 10 proteins including chloroplastic ATP synthase subunit b, D2 protein of PSII, D1 protein of PSII reaction centre, and light harvesting complex II protein, most of which are associated with photosynthetic activities in PSII. The results suggest that the marine alga P. parvum altered the biosynthesis of several photosynthetic proteins in order to cope with low Fe conditions., M. M. Rahman, M. A. Rahman, T. Maki, T. Nishiuchi, T. Asano, H. Hasegawa., and Obsahuje bibliografii
A modified exponential model was used to describe light-response curves of Nicotiana tabacum L. The accuracies of an exponential model, a nonrectangular hyperbola model, a rectangular hyperbola model, a modified rectangular hyperbola model and the modified exponential model were evaluated by Mean square error (MSE) and Mean absolute error (MAE). The tests MSE and MAE of the modified exponential model were the lowest among the five models. The light saturation point (LSP) obtained by the exponential model, the nonrectangular hyperbola model and the rectangular hyperbola model were much lower than the measured values, and the maximum net photosynthetic rates (Pmax) calculated from these models, were greater than the measured values. Pmax at LSP of 1,077 μmol m-2 s-1 calculated by the modified exponential model was 12.34 μmol(CO2) m-2 s-1, which was more accurate than the values obtained from the modified rectangular hyperbola model. The results show that the modified exponential model is superior to other models for describing light-response curves. and Z. Y. Chen ... [et al.].
In this paper, we present a novel quantitative description of intracellular and t-tubular Ca2+ dynamics in a model of rat cardiac ventricular myocyte. In order to simulate recently published data, the model incorporates t-tubular and peripheral dyads and intracellular subspaces, segmentation of the t-tubular luminal volume, reformulation of the inactivation properties of t-tubular land peripheral L-type calcium current (ICa) and a description of exogenous Ca2q+ buffer function in the intracellular space. The model is used to explore activity-induced changes of ion concentration in the intracellular and t-tubular spaces and their role in excitation - contraction coupling in ventricular myocytes. and Obsahuje Appendix se seznamy literatury, užitých zkratek a symbolů