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1 Although it is well established that nitrogen and light play major roles in structuring plant communities across the landscape, it is not as clear how they structure communities within forest stands. Virtually nothing is known about within-stand structure of understorey communities of herbs and small shrubs in near-boreal forests. 2 We tested the(More)
Bivalve mollusks, such as the freshwater mussel Anodonta cygnea, show seasonal changes in calcification. This cycle of calcification must either be a cause or a consequence for seasonal fluctuations in the organic composition of the animal's fluids, haemolymph and extrapallial fluid, the liquid media for biomineralization. We monitored the fluids of A.(More)
Despite many studies of the percent loss of hydraulic conductivity in excised branches, there is doubt as to whether cutting stems in air introduces unnatural embolism into the xylem at the cut surface. To address this question, hydraulic conductivity was measured in seedlings of northern red oak (Quercus rubra L.) and rooted scions of eastern cottonwood(More)
The heavy metals, Cd, Cu, Cr, Zn, and Pb, were used to incubate healthy specimens of the freshwater mussel species, Anodonta cygnea. Afterwards, their biological fluids, either haemolymph or extrapallial fluid were analyzed for the presence of several organic constituents, known to be important for biomineralization, such as proteins, glycosaminoglycans(More)
We compared fruiting data derived simultaneously from fruit traps placed on the ground and from canopy-surveyed plots in a terra firme rain forest, Colombian Amazonia. Values derived from the canopy-surveyed plots were higher than fruit-trap estimates. Fruiting patterns obtained throughout both methods were not correlated. Our results showed that the(More)
An orthorhombic structure α-chitin, probably in the form of a chitin-protein complex, was identified in the matrix of the shell of Anodonta cygnea by X-ray diffraction. Aragonite crystals of pseudohexagonal symmetry were also found by a Lauegram on the nacreous layer of the shell. The orthorhombic structure of these two compounds together with the identical(More)
The knowledge on diet composition of the freshwater mussel Diplodon enno (Ortmann) would aid in its culture and propagation allowing, this way, the replacement of natural endangered populations in Brazil. Microalgae are the main food source for captive mussels and unionids have displayed an ability to sort algae based on the cellular characteristics prior(More)
The very neutron-rich oxygen isotopes 25 O and 26 O are investigated experimentally and theoretically. The unbound states are populated in an experiment performed at the R3B-LAND setup at GSI via proton-knockout reactions from 26 F and 27 F at relativistic energies around 442 and 414 MeV/nucleon, respectively. From the kinematically complete measurement of(More)
The purpose of this work was to synthesize and characterize the thiatetraaza macrocycle 1-thia-4,7,10,13-tetraazacyclopentadecane ([15]aneN4S). Its acid-base behaviour was studied by potentiometry at 25 °C and ionic strength 0.10 M in KNO3. The protonation sequence of this ligand was investigated by 1H-NMR titration that also allowed the determination of(More)
In order to increase the available data on chromosomal polymorphism of Drosophila prosaltans, 15 strains were studied. A new inversion was found and additional information related to the distribution area of previously described inversions has been obtained. A survey of the cytological data accumulated to the present, referring to 33 strains, shows that D.(More)
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