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Start Over Coverage 91-97

1. A Himalayan monsoonal location exhibiting unusually high preponderance of C4 grasses

Creator:
Rama Das, V. S. and Vats, S. K.
Format:
print
Type:
model:internalpart and TEXT
Language:
Multiple languages
Description:
An unexpectedly large proportion of C4 grasses was found in a moderately temperate and moist Himalayan location during monsoon period. 79 % of total grasses occurring in the area were found to be C4. Several grasses hitberto unreported as C4 háve now been recorded. The principál cause for the natural abundance of C4 species is presumably low atmospheric CO2 levels rallua' tlian the aridity and warmer temperatures. The finding adds a new dimension to our knowledge of natural distribution of the C4 species.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

2. Fázově koherentní přenos stabilní optické frekvence Brno - Praha po optickém vlákně délky 306 km

Creator:
Číp, Ondřej, Čížek, Martin, Pravdová, Lenka, Hucl, Václav, Řeřucha, Šimon, Hrabina, Jan, Mikel, Břetislav, Lazar, Josef, Vojtěch, Josef, and Smotlacha, Vladimír
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
laser, optical fiber, optical and frequency transfer, optical frequency standard, optické vlákno, přenos frekvence a času, and normál optické frekvence
Language:
Czech
Description:
Thanks to the development of fiber optic technologies for the Internet, large cities and metropolitan networks are now well connected through the fiber optic technology. Since the mid-nineties of the last century a rapid research in the transmission of stable frequencies via optical fibers has been introduced. It is necessary for mutual remote comparison of optical frequency standards via optical fibers. But in order to transmitting optical frequencies through photonic data networks, the key task is to compensate the Doppler shift that is induced in the fibers by external influences, such as particularly changes in the temperature or acoustic noise and mechanical vibration environment in which the fibers are installed. In this work we present some techniques to compensate these unwanted effects. Furthermore, we present the realization of an optical system and measurement parameters achieved by the phase-coherent optical transmission of the optical frequency standard working at a wavelength of 1540.5 nm. The optical frequency dissemination with the stable transport delay has been established on the fiber optic link leading from the Institute of Scientific Instruments ASCR Brno to headquarters of national provider CESNET in Prague over the optical fiber with the length of 306 km. The work includes the verification and measurement of changes of the transport delays using simultaneous bidirectional transmission of 1PPS signals from the instrument based atomic clocks placed in both ends of the same optical fiber. and Díky rozvoji komunikačních technologií pro internet jsou nyní dobře propojena velká města i metropolitní sítě optickými vlákny, čímž lze zajistit čistě fotonický přenos signálů na vzdálenosti až stovek kilometrů. Od poloviny devadesátých let minulého století probíhá intenzivní výzkum v oblasti přenosu stabilních frekvencí pomocí optických vláken, který je nezbytný pro vzájemná dálková porovnávání normálů optické frekvence. Aby však bylo možné přenášet optické frekvence přes běžné fotonické datové sítě, je nezbytné kompenzovat dopplerovský posuv, který je ve vláknech indukován působením vnějších vlivů, jako jsou zejména změny teploty či akustické a mechanické vibrace prostředí, ve kterém jsou vlákna uložena. V práci představujeme vybrané techniky kompenzace těchto nežádoucích efektů. Dále prezentujeme vlastní realizaci optické soustavy a měření dosažených parametrů fázově koherentního přenosu optické frekvence normálového laseru pracujícího na vlnové délce 1540,5 nm z pracoviště Ústavu přístrojové techniky AV ČR v Brně do ústředí poskytovatele fotonických služeb CESNET v Praze po optickém vlákně délky 306 km. Součástí výsledků je i verifikace měření změn dopravního zpoždění pomocí obousměrného simultánního přenosu signálů 1PPS z přístrojových atomových hodin umístěných v obou lokalitách po stejném optickém vlákně.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

4. New species of Choleoeimeria (Apicomplexa: Eimeriidae) from the veiled chameleon, Chamaeleo calyptratus (Sauria: Chamaeleonidae), with taxonomic revision of eimerian coccidia from chameleons

Creator:
Sloboda, Michal and Modrý, David
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
Coccidia, Eimeriorina, Choleoeimeria, and taxonomy
Language:
English
Description:
Coprological examination of 71 samples from a breeding colony of veiled chameleons, Chamaeleo calyptratus Duméril et Duméril, 1851, revealed a presence of two species of coccidia. In 100% of the samples examined, oocysts of Isospora jaracimrmani Modrý et Koudela, 1995 were detected. A new coccidian species, Choleoeimeria hirbayah sp. n., was discovered in 32.4% of samples from the colony. Its oocysts are tetrasporocystic, cylindrical, 28.3 (25-30) × 14.8 (13.5-17.5) µm, with smooth, bilayered, ~1 µm thick wall. Sporocysts are dizoic, ovoidal to ellipsoidal, 10.1 (9-11) × 6.9 (6-7.5) µm, sporocyst wall is composed of two plates joined by a meridional suture. Endogenous development is confined to the epithelium of the gall bladder, with infected cells being typically displaced from the epithelium layer towards lumen. A taxonomic revision of tetrasporocystic coccidia in the Chamaeleonidae is provided.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

5. Source-to-sink relationship between green leaves and green petals of different ages of the CAM orchid Dendrobium cv. Burana Jade

Creator:
He, J. and Woon, W. L.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
CAM acidity, chlorophyll fluorescence induction, photosynthetic O2 evolution, and saccharides
Language:
Multiple languages
Description:
Photosynthetic capacities of green leaves (GL) and green flower petals (GFP) of different ages of the CAM plant Dendrobium cv. Burana Jade were studied through chlorophyll (Chl) content, Chl fluorescence characteristic Fv/Fm, maximal photosynthetic O2 evolution rates (P max), and CAM acidities [dawn/dusk fluctuations in titratable acidity (TA)]. All these photosynthetic parameters were higher in GL than in GFP. Among the different ages of GFP, the young GFP had significant higher readings of all photosynthetic parameters than the oldest GFP, indicating that reduced photosynthesis occurred in the senesced GFP. The source-to-sink relationship between GL and GFP was also studied by comparing the diurnal changes in contents of total soluble and insoluble sugars and TA between the fully irradiated (FI) control (with both irradiated GL and GFP) and GL-darkened plants (covering all GL with aluminium foils, leaving only the GFP exposed to radiation). CAM acidities were much lower in GL darkened with aluminium foils compared to those of FI-GL while there were no differences in CAM acidities of their GFP. The contents of total soluble and insoluble sugars and the CAM acidities of GL towards the end of the day were lower in GL-darkened plants compared to that of FI-plants. Hence CAM acidities of GL depended on their saccharide contents. However, diurnal changes of TA in GFP were similar in all GFP regardless of their ages, with or without GL photosynthetic sources. Thus CAM acidities of GFP are independent of GL saccharides. However, lower saccharide content in GFP (especially the oldest GFP) of GL-darkened plants implies that GFP function as sinks and depend on saccharides exported from GL for its development and growth. and J. He, W. L. Woon.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public