Growth, net photosynthetic rate (PN), chlorophyll fluorescence induction kinetics, and stromal fructose-1,6-bisphosphatase (sFBPase) in annual legumes native to the Mediterranean region, two clovers (Trifolium subterraneum L. ssp. oxaloides Nyman cv. Clare and T. michelianum Savi cv. Giorgia) and two Medicago species (M. polymorpha L. cv. Anglona and M. truncatula Gaertn. cv. Paraggio), shifted from 20 to 10 °C for 1 d or developed at 10 °C were compared with controls kept at 20 °C. Cold development produced a larger stimulation of growth in the clover cv. Giorgia and the Medicago cv. Paraggio. Transferring plants to low temperatures affected PN relatively less in clovers than in Medicago plants. Development at 10 °C relieved the inhibition of photosynthesis in Giorgia and Paraggio, but not in Clare and Anglona, which correlated with increases in the maximum rate of carboxylation by ribulose-1,5-bisphosphate carboxylase/oxygenase, RuBPCO (Vcmax), and the photon-saturated rate of electron transport (Jmax). In Medicago, transfer from high to low temperature inhibited photosynthesis in a lesser extent in Anglona than in Paraggio, which showed severe limitations at level of Vcmax and Jmax. Development at 10 °C in Paraggio produced an efficient photosynthetic cold acclimation, this being associated with a two-fold increase of quantum yield of photosystem 2 electron transport (ΔF/F'm) and with the activity of sFBPase. By contrast, Anglona showed an irreversible inhibition of PN coupled with the reduction of carbon metabolism by impairment of Calvin cycle enzyme activities such as RuBPCO and sFBPase, resulting in a poor cold acclimation of photosynthesis in this cultivar. and M. C. Antolín, M. Hekneby, M. Sánchez-Díaz.
Modelling of supercritical turbulent flow in an open channel with transversal ribs on its bottom was concentrated particularly on the development of flow separation behind ribs and on the corresponding changes of free surface. Further, the pressure drag of individual ribs was investigated including its dependence on the rib spacing, as well as the origin of secondary flow near the side walls of the channel behind ribs. Numerical results obtained by the software ANSYS CFX 11,0 were compared with experiments carried out by means of LDA and PTV techniques in free-surface water experiments carrid out by means of LDA and PIV techniques in free-surface water channel 200 x 200 mm with one or two transversal ribs 10 x 10 mm with various spacing. and Obsahuje seznam literatury
The text sets out to examine the hypothesis that Jan Neruda had a hand in the editorship or authorship of poems signed by Josef Barák, thus examining the conclusion of the study by Petr Plecháč and Jiří Flaišman: “Barák’s problem: Neruda from the standpoint of contemporary stylometry” (Česká literatura No. 5/2017), who deduced that there was a textual similarity between the two authors and attempted to explain it in terms of the theory that Jan Neruda was involved in editing or co-authoring his work. The present text analyses Jan Neruda’s editing practice during the 1859–1860 period on the basis of a comparison of newly discovered manuscripts of poems by A. Heyduk, V. A. Crha, E. B. Kaizl and J. V. Jahn with printed material in publications edited by Neruda, particularly in the first annual volume of the journal Obrazy života (Images of Life, 1859) and in the book edition of Heyduk’s Básně (Poems, 1859). On the basis of this analysis and the critical determination of constraints emerging from the available archive material under analysis, the author characterizes Jan Neruda’s editorial work, concluding that it does not form a basis for the hypothesis that Neruda made decisive alterations to the text of the poems by Josef Barák resulting in a change in stylometric indicators. and Text si klade za cíl prozkoumat hypotézu o redakčním či autorském podílu Jana Nerudy na básních podepsaných Josefem Barákem. Prověřuje tak závěr studie Petra Plecháče a Jiřího Flaišmana „Problém Barák: Neruda z pohledu současné stylometrie“ (Česká literatura č. 5/2017), kteří dospěli k závěru o textové podobnosti obou autorů a pokusili se ji vysvětlit hypotézou o redakčním či spoluautorském podílu Jana Nerudy. Přítomný text analyzuje redakční praxi Jana Nerudy v daném období let 1859‒1860 na základě srovnání nově nalezených rukopisů básní A. Heyduka, V. A. Crhy, E. B. Kaizla a J. V. Jahna s otisky v publikacích, na nichž se Jan Neruda podílel jako redaktor, především v prvním ročníku časopisu Obrazy života (1859) a v knižním vydání Básní A. Heyduka (1859). Na základě tohoto rozboru a po kritickém stanovení omezení vyplývajících z analyzovaného dostupného archivního materiálu dochází autor k charakteristice redakční práce Jana Nerudy, a vyslovuje závěr, že není podklad pro hypotézu o Nerudových razantních změnách textu básní Josefa Baráka, které by měly za následek proměnu stylometrických ukazatelů.
In a recent paper the authors proposed a lower bound on $1 - \lambda _i$, where $\lambda _i$, $ \lambda _i \ne 1$, is an eigenvalue of a transition matrix $T$ of an ergodic Markov chain. The bound, which involved the group inverse of $I - T$, was derived from a more general bound, due to Bauer, Deutsch, and Stoer, on the eigenvalues of a stochastic matrix other than its constant row sum. Here we adapt the bound to give a lower bound on the algebraic connectivity of an undirected graph, but principally consider the case of equality in the bound when the graph is a weighted tree. It is shown that the bound is sharp only for certain Type I trees. Our proof involves characterizing the case of equality in an upper estimate for certain inner products due to A. Paz.
Plant traits of Malcolmia littorea growing at the Botanic Garden of Rome and transplanted from the wild population developing along the Latium coast (Italy) were analyzed. The highest photosynthetic rates [PN, 22.5 ± 0.5 μmol(CO2) m-2 s-1], associated to the highest chlorophyll content (Chl, 60 ± 5 SPAD units), and respiration rates [R, 11.1 ± 0.2 μmol(CO2) m-2 s-1] were reached in spring, when mean air temperature (Tm) was in the range 17°C to 23°C. PN, Chl, and R decreased by 86, 38, and 59% in summer when mean maximum air temperature (Tmax) was 30.3 ± 2.6°C. Leaf water potential decreased by 34% in summer compared to the spring value, and it was associated to a relative water content (RWC) of 74 ± 4%, and to a water-use efficiency (WUE) of 2.15 ± 0.81 μmol(CO2) mmol-1(H2O). Moreover, also low air temperatures determined a significant PN and R decreases (by 52 and 40% compared to the maximum, respectively). Responsiveness of gross photosynthetic rate (Pg) to R was higher than that to PN as underlined by the slope of the regression line between the two variables. The results underlined a low tolerance to both high- and low air temperatures of M. littorea. The selected key traits (R, WUE, Chl) by the discriminant analysis might be used to monitor the M. littorea wild population in the long time. The ex situ cultivated plants could be propagated and used to increase the individuals number of the wild population. and L. Gratani ... [et al.].