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33712. δ13C values, photosynthetic pathways, and plant functional types for some plants from saline meadows, Northeastern China
- Creator:
- Wang, R. Z.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- C4 photosynthetic pathway, saline meadow species, stable carbon isotope ratio (δ13C), and total carbon content
- Language:
- Multiple languages
- Description:
- Based on stable carbon isotope ratio (δ13C) measurements, photosynthetic pathway types were determined for 61 species in 54 genera and 24 families of flowering plants from the saline meadows of Northeastern China. Of these total vascular plants, 18 species in 17 genera from 6 families were found to have C4 photosynthesis; 43 species in 38 genera from 20 families had C3 photosynthesis. Six dicotyledonous species exhibited C4 pathway, 12 monocotyledonous species were found with C4 photosynthesis. The dicotyledonous C4 species had relative greater mean δ13C value and less total carbon content than both monocotyledonous C4 and C3 species. Most dicotyledonous C4 species were annual forbs and halophytes. Some C4 species had been previously documented, but their δ13C values varied remarkably from those of the present study. Even though there are some fluctuations for the δ13C values of some C4 species, δ13C value was still more reliable for C3 and C4 identification than the use of the enzyme ratio method and of low CO2 compensation concentration.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
33713. ΔpH-dependent fluorescence quenching and its photoprotective role in the unicellular red alga Rhodella violacea
- Creator:
- Ritz, M., Neverov, K. V., and Etienne, A.-L.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- chlorophyll irradiance, light-harvesting chlorophyll protein complex, photoinhibition, photosystems 1 and 2, and phycobilisome
- Language:
- Multiple languages
- Description:
- Plants have developed various photoprotective mechanisms to resist irradiation stress. One of the photoprotective mechanisms described in the literature for LHC2-containing organisms involves a down-regulation of photosystem (PS) 2 occurring simultaneously with the build-up of a proton gradient across the thylakoid membrane (ΔpH). It is often correlated with deepoxidation of xanthophylls located in LHC2. In Rhodophyta instead of LHC2, the peripheral antenna of PS2 consists of a large extramembrane complex, the phycobilisome (PBS), which transfers its excitation to the core antennae of PS2 composed of the CP43 and CP47 protein-chlorophyll complexes and there is no xanthophyll cycle. In the red alga Rhodella violacea a ΔpH-dependent chlorophyll (Chl) a fluorescence quenching can be formed. We characterised this quenching, studied the effects of various irradiances and inhibitors. Under photoinhibitory conditions, the ΔpH-dependent Chl fluorescence quenching exerts a photoprotective role and delays the kinetics of photoinhibition. It is the first time that such a photoprotective mechanism is described in PBS-containing organisms. and M. Ritz, K. V. Neverov, A.-L. Etienne.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
33714. ζ Ophiuchi: a stellar and interstellar Pandora´s box
- Creator:
- Walker, Gordon A. H.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- hot emission-line (OBAe) stars, interstellar lines, and spectral changes
- Language:
- Czech
- Description:
- The broadening of the photospheric lines in ζ Ophiuchu by very rapid rotation allows not ony mapping of its surface velocities and temperature distribution, but makes the star an excellent probe for a profusion of sharp interstellar lines. Being bright, it is a good object for smaller telescopes. Apart from discovering nonradial oscillations in its atmosphere over twenty years ago and a significant temperature differential between pole and equator (the von Zeipel effect), I have recently assisted in the discovery of some 30 lines of interstellar C3 near 405 nm - the first carbon chain to have been found in a diffuse interstellar cloud and at a much higher concentration than expected.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
33715. ϕ-divergences, sufficiency, Bayes sufficiency, and deficiency
- Creator:
- Liese, Friedrich
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- divergences, sufficiency, Bayes sufficiency, and deficiency
- Language:
- English
- Description:
- \vspace{-1.6cm} The paper studies the relations between ϕ-divergences and fundamental concepts of decision theory such as sufficiency, Bayes sufficiency, and LeCam's deficiency. A new and considerably simplified approach is given to the spectral representation of ϕ-divergences already established in Österreicher and Feldman \cite{OestFeld} under restrictive conditions and in Liese and Vajda \cite{LiV06}, \cite{LiV08} in the general form. The simplification is achieved by a new integral representation of convex functions in terms of elementary convex functions which are strictly convex at one point only. Bayes sufficiency is characterized with the help of a binary model that consists of the joint distribution and the product of the marginal distributions of the observation and the parameter, respectively. LeCam's deficiency is expressed in terms of ϕ-divergences where ϕ belongs to a class of convex functions whose curvature measures are finite and satisfy a normalization condition.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public