Search results for "feature"
showing 10 items of 4091 documents
Distribution, floristic structure and habitat requirements of the riparian forest community Populetum talassicae ass. nova in the Central Pamir-Alai …
2013
This paper discusses the floristic structure, distribution and habitat requirements of a new forest syntaxon, <em>Populetum talassicae </em>ass. nova. The potential range of the <em>Populetum talassicae </em>association comprises the central Pamir-Alai and Tian-Shan Mountains in Middle Asia. The biotope of this community comprises high mountain river valleys and shore zones of mountain lakes situ- ated at elevations between 2200 and 2750 m. Phytocoenoses of the <em>Populetum talassicae </em>association are characterized by a clear predominance in the tree layer of a characteristic species of the association ‒ <em>Populus talassica</em>. Shrubs…
Artificial Reefs in North-West Sicily: Comparisons and Conclusions
2000
The most notable features of the biotic colonization and fishing yield of artificial reefs are a straightforward response to local environmental conditions. When applying this assumption to the artificial reefs of north-west Sicily, the features that distinguish the reefs from each other are largely consistent with the major hydrographic characteristics of the Gulf of Castellammare, the Bay of Carini and the Gulf of Palermo. The differences in environmental conditions in the three biotopes have made it possible to compare the colonization of artificial reefs in unpolluted oligotrophic water (Bay of Carini), eutrophic water (Gulf of Palermo) and water with heavy siltation rates (Alcamo Marin…
Consequences of the discovery of Stenasellus (Crustacea, Isopoda, Asellota) 2 in the underground waters of Oman (Arabian Peninsula)
1999
An overview of the present knowledgeof the family Stenasellidae (Asellota: Aselloidea) is presented, focusing on the success of recent investigations of the underground waters of Oman (S.E. Arabian Peninsula). We take up the discovery of four new species of the genus Stenasellus: small species adapted to interstitial biotopes and larger ones typical of karstic aquifers. These species cohabit in ecotones between interstitial and karstic water systems. The putative presence of stenasellids in hypogean waters of Yemen and South Iran is suggested. The taxonomic status of the genus Stenasellus auct. needs to be reconsidered in the future. A scenario to explain the origin and the presence of thes…
Soil microbial activity and functional diversity in primeval beech forests
2015
Virgin forests are unique ecosystems, which can be used as etalon for basic biocoenotic investigation. Soil microorganisms are very sensitive reagents on influence of biotical factors, and at the same time are the active producers of phytotoxic and phytostimulating exometabolites. Studies of soil microbiota were conducted in virgin beech forests of Shyrokoluzhansky massif of the Carpathian Biosphere Reserve. It was found the ratio and the number of different ecological-trophic groups of soil microorganisms changes with altitude. So the number of ammonificators with increasing of altitude above sea level was reduced. The soil at altitude of 1,100 meters above sea level was characterized by m…
Can grassland plant communities be preserved on road and railway verges?
2000
Semi-natural grasslands are a threatened biotope type in many countries. Typical grassland plant species are adapted to continuous grazing or mowing that keeps the envi- ronment open. With the decline in grassland area, these spe- cies are ever more reliant on alternative habitats such as road verges. To find out whether plant communities comparable to those of semi-natural grasslands can be maintained on modern road and railway sides, the vegetation of 92 grasslands and 90 road and railway verges was studied. These biotope types were compared with each other according to their community structure, total number of species, number of grassland species and restricted-range diversity. Further …
Osservazioni su alcuni aspetti di vegetazione lacustre nella Sicilia centrale
1977
Abstract Some aspects of lacustrine vegetation in the central Sicily.—The Authors give a short comparative survey of some hydrophytic facies observed in two small ponds near Caltanissetta, in the central Sicily. In addition to the classical zonation, typical of such water logged (or: swamp) biotopes, a Potamogeton pectinata-Chara vulgaris association is described. The presence of monospecific facies to be referred to the Lemnetum gibbae (Koch, 1954) Miyaw. et J. Tx., 1960 is ultimately reported.
Atypical Antipsychotics in the Treatment of Acute Bipolar Depression with Mixed Features: A Systematic Review and Exploratory Meta-Analysis of Placeb…
2016
Evidence supporting the use of second generation antipsychotics (SGAs) in the treatment of acute depression with mixed features (MFs) associated with bipolar disorder (BD) is scarce and equivocal. Therefore, we conducted a systematic review and preliminary meta-analysis investigating SGAs in the treatment of acute BD depression with MFs. Two authors independently searched major electronic databases from 1990 until September 2015 for randomized (placebo-) controlled trials (RCTs) or open-label clinical trials investigating the efficacy of SGAs in the treatment of acute bipolar depression with MFs. A random-effect meta-analysis calculating the standardized mean difference (SMD) between SGA an…
Intraportal transplantation of allogenic pancreatic islets encapsulated in barium alginate beads in diabetic rats.
2003
The survival of microencapsulated islets transplanted into the unmodified peritoneal cavity is limited, even if capsular overgrowth is restricted to a minimum, due to an insufficient oxygen supply to the islets. Therefore, research efforts should focus on finding or creating a transplantation site, which permits a closer contact between the encapsulated islets and the blood. For this reason, the liver could be an interesting candidate. The aim of the present study was to test the hypothesis that the intraportal transplantation of allogenic islets encapsulated in small-sized barium alginate beads is safe and succeeds to induce normoglycemia in diabetic rats. The intraportal transplantation o…
Origin of potassic postcollisional volcanic rocks in young, shallow, blueschist-rich lithosphere
2020
Unusually high Th/La in K-rich orogenic rocks may indicate shallow blueschist-rich sources in accretionary settings.
From intra-oceanic subduction to arc accretion and arc-continent collision: Insights from the structural evolution of the Río San Juan metamorphic co…
2013
The Río San Juan metamorphic complex exposes a segment of a high-pressure subduction-accretionary complex built during Caribbean island arc-North America continental margin convergence. It is composed of accreted arc- and oceanic-derived metaigneous rocks, serpentinized peridotites and minor metasediments forming a structural pile. Combined detailed mapping, structural and metamorphic analysis, and geochronology show that the deformation can be divided into five main events (D1eD5). An early subduction-related D1 deformation and M1 metamorphism produced greenschist (mafic rocks of the Gaspar Hernández peridotite-tectonite), blueschist and eclogite (metamafic blocks in the Jagua Clara mélang…