Search results for "visual_art.visual_art_medium"
showing 10 items of 2982 documents
Radon levels in the Valencian community (Spain). I. Results in the province of Valencia (1990–1991)
1995
Abstract Two-day radon screening measurements with charcoal canisters were made in buildings in the province of Valencia throughout the years 1990 and 1991. An average indoor concentration of 34 Bq m −3 was found, and 9% of all measurements exceeded the recommended EPA limit of 148 Bq m −3 .
BLOOD PARASITES AND MALE FITNESS IN THE PIED FLYCATCHER
1993
In vertebrates the effect of parasites on host ecology has almost been ignored. Recently the view that well-adapted parasites do not harm their hosts has been challenged and there is growing evidence that parasites do have a present-day effect on a great variety of host fitness components. The pied flycatcher is a small migratory passcrine bird. Any decrease in condition caused by disease should affect its ability to cope with physical demands of migration. Here we examine whether blood parasites have any effect on male arrival time. Males infected with Trypanosoma arrived on average 2 days later than males with no Trypanosoma infection. Infected males also had shorted tails and tended to h…
Arthropod-induced neoplastic formations on trees change photosynthetic pigment levels and oxidative enzyme activities
2005
Abstract In order to test the hypothesis that arthropod-induced neoplastic formations on trees affect biochemical characteristics of both the newly formed galls and host plant tissues, biochemical characteristics with a possible adaptive role were determined in nine gall-former–host tree combinations. Photosynthetic pigments, extractable protein content, and oxidative enzyme activities were determined in gall tissues, leaf tissues of galled leaves, and leaves on ungalled tree branches. Neoplastic tissues were characterized by a low content of photosynthetic pigments, decreased chlorophyll a/b ratio, lower extractable protein content, and decreased activities of peroxidase and polyphenol oxi…
Azide and chloride binding to carboxypeptidase A in the presence of L-phenylalanine
1990
The interaction of chloride with native and cobalt (Co)-substituted carboxypeptidase-A (CPD) has been investigated by 35Cl nuclear magnetic resonance (NMR) spectroscopy in the presence and absence of L-Phe. The affinity constants of azide and chloride toward the Co(II)CPD·L-Phe complex have been measured by electronic spectroscopy. The correlation times determining T1 and T2 for the 35Cl nuclei are related to movements inside the cavity. In the presence of L-Phe, the anions bind to the metal with a relatively high affinity at pH values below 6. Anion binding to the Co enzyme can be analyzed in terms of the three protonation state model for the enzyme (EH2 α EH α E). In the presence of L-Phe…
Effect of organic matrices on the determination of the trace element chemistry (Mg, Sr, Mg/Ca, Sr/Ca) of aragonitic bivalve shells (<i>Arctica …
2010
The element chemistry of biogenic carbonates can provide important data on past environments. However, the Sr/Ca and Mg/Ca ratios as well as the Mg and Sr concentrations of biological carbonates, especially aragonitic bivalves often depart from apparent thermodynamic equilibrium. When measured in situ by means of LA-ICP-MS, the Mg concentration is often substantially enriched (two- to threefold) near the organic-rich, annual growth lines. To test the hypothesis that some organic components exert a major influence on the skeletal metal content, the element chemistry of different shell components (insoluble organic matrix, IOM; dissolved CaCO3 and soluble organics, SOM) of Arctica islandica w…
Ucriol, an epoxy-diterpene from Sideritis syriaca
1983
Abstract The isolation of a new epoxy-diterpene from the inflorescence of Sideritis syriaca (S. sicula Ucria) is described. Its structure and stereochemistry were established by spectroscopy and partial synthesis.
Prenylated benzopyran derivatives from two Polyalthia species
1996
Two new benzopyran derivatives, (6E,10E)-isopolycerasoidol and polycerasoidin methyl ester, have been isolated from a methanolic extract of the stem bark of Polyalthia cerasoides. Their structures were established on the basis of chemical and spectral evidence. Polyalthia sclerophylla contains (6E,10E)-isopolycerasoidol, besides the known polycerasoidin and polycerasoidol. In addition, a known phenylpropene derivative, trans-asarone, has also been isolated from both species and fully characterized.
ChemInform Abstract: Syntheses of Some Biologically Active Compounds from Stilbenes Isolated from the Bark of Picea abies.
2010
From the four stilbenes 1–4 isolated from the bark of Picea abies seven compounds 5–11 were obtained by hydrogenation or permethylation. 1H-, 13C-NMR and mass spectra were used for their characterization. The antileukemic activity of each compound was preliminary tested. Some compounds were further tested for their anti-HIV activity.
Distribution ofLeprariain Latvia in Relation to Tree Substratum and Deciduous Forest Type
2012
The aim of the study was to evaluate the distribution of Lepraria lichen species in dry deciduous forests, in relation to tree substratum and forest characteristics. In total, 34 localities with 1020 trees (13 tree species) were studied in different parts of Latvia. Lepraria spp. were found on 642 trees: L. eburnea on 8 trees, L. incana on 80 trees, and L. lobificans on 568 trees. Lepraria eburnea was recorded for the first time in Latvia. Tree species, tree bark crevice depth, inclination, pH and forest type were the most important variables explaining the presence of Lepraria species. Lepraria incana was associated with Quercus robur and Tilia cordata, while L. lobificans was associated w…
Incidence of heavy metals in the application of inorganic fertilizers to rice farming soils (Valencia, Spain)
1996
The presence of Cd, Co, Cu, Ni, Pb, Zn, Fe and Mn in different inorganic fertilizers (urea, calcium superphosphate, iron sulphate and copper sulphate) are evaluated and the contribution of these metals to the soils in this way is estimated. The studied zone corresponds to rice farming and is at the north of Albufera Natural Park (Valencia, Spain). The results obtained show that Superphosphate is the fertilizer that contains the highest levels of Cd, Co, Cu and Zn as impurities. Copper sulphate and iron sulphate have the most significant contents of Pb, and are the only fertilizers in which Ni is detected. The most significant additions of impurities that the soil received by agricultural pr…