Three vernacular texts from late-13th-century Bohemia, in Middle High German and Old Czech, integrate motifs associated with the Holy Land, pilgrimage and the crusades. The romance Wilhalm von Wenden manifests the late Přemyslids’ royal ideology by portraying an independent, pious ruler who derives authority from Jerusalem. The Alexandreis explores the psychology of a military expedition to provide ground for moral reflection and draws on cartography to exploit the symbolism of Jerusalem’s geographic centrality. The crusade-related details in the Legend of Saint James the Less attest to an informed use of intertextual practices.
Portrét kanadského fyzika, který získal v r. 2009 Nobelovu cenu za vynález zobrazovacího polovodičového obvodu - CCD senzoru. and Rubrika: Nobelova cena za fyziku
Precise wind energy potential assessment is vital for wind energy generation and planning and development of new wind power plants. This work proposes and evaluates a novel two-stage method for location-specific wind energy potential assessment. It combines accurate statistical modelling of annual wind direction distribution in a given location with supervised machine learning of efficient estimators that can approximate energy efficiency coefficients from the parameters of optimized statistical wind direction models. The statistical models are optimized using differential evolution and energy efficiency is approximated by evolutionary fuzzy rules.
Seasonal variability of maximum quantum yield of PSII photochemistry (Fv/Fm) was studied in needles of Taxus baccata seedlings acclimated to full light (HL, 100% solar irradiance), medium light (ML, 18% irradiance) or low light (LL, 5% irradiance). In HL plants, Fv/Fm was below 0.8 (i.e. state of photoinhibition) throughout the whole experimental period from November to May, with the greatest decline in January and February (when Fv/Fm value reached 0.37). In ML seedlings, significant declines of Fv/Fm occurred in January (with the lowest level at 0.666), whereas the decline in LL seedlings (down to 0.750) was not significant. Full recovery of Fv/Fm in HL seedlings was delayed until the end of May, in contrast to ML and LL seedlings. Fv/Fm was significantly correlated with daily mean (T mean), maximal (T max) and minimal (T min) temperature and T min was consistently the best predictor of Fv/Fm in HL and ML needles. Temperature averages obtained over 3 or 5 days prior to measurement were better predictors of Fv/Fm than 1- or 30-day averages. Thus our results indicate a strong light-dependent seasonal photoinhibition in needles of T. baccata as well as suggest a coupling of Fv/Fm to cumulative temperature from several preceding days. The dependence of sustained winter photoinhibition on light level to which the plants are acclimated was further demonstrated when plants from the three light environments were exposed to full daylight over single days in December, February and April and Fv/Fm was followed throughout the day to determine residual sensitivity of electron transport to ambient irradiance. In February, the treatment revealed a considerable midday increase in photoinhibition in ML plants, much less in HL (already downregulated) and none in LL plants. This suggested a greater capacity for photosynthetic utilization of electrons in LL plants and a readiness for rapid induction of photoinhibition in ML plants. Further differences between plants acclimated to contrasting light regimes were revealed during springtime de-acclimation, when short term regeneration dynamics of Fv/Fm and the relaxation of nonphotochemical quenching (NPQ) indicated a stronger persistent thermal mechanism for energy dissipation in HL plants. The ability of Taxus baccata to sustain winter photoinhibition from autumn until late spring can be beneficial for protection against an excessive light occurring together with frosts but may also restrict photosynthetic carbon gain by this shade-tolerant species when growing in well illuminated sites. and P. Robakowski, T. Wyka.