نتایج جستجو برای: surface species
تعداد نتایج: 1154343 فیلتر نتایج به سال:
The effect of the paleoclimatic and paleoenvironmental changes on the structure of the bioticcommunities are stronger and better recorded in the shelf area than in the open sea. The present study isdevoted to impact of climatic events on some species of calcareous nannofossils. For this reason, 17samples of surface sediments of the Persian Gulf were studied. Preservation of calcareous nannofoss...
The seed micromorphological characters of 15 taxa of Iranian Pyrus comprising 22 individuals were examined by Scanning Electron Microscopy (SEM) and Digital Microscopy (DM) for the first time in this survey. For the assessment of probable ecological effects, several individuals of some widespread species were studied. After collecting several samples of each wild taxa of Pyrus from different lo...
Some bioecological aspects of grape leafhopper, Arboridia kermanshah Dlabola, including: the egg distribution under the leaf surface, eggs and nymphs spatial distribution on the vine arms, the adult distribution on three strata of the vine canopy, the adult diel activities and the geographical distribution of this species in Isfahan province were studied. Samplings were done in the 1997. The eg...
Photocatalytic H2 production over TiO2 has attracted tremendous attention and achieved great progress, but the active hydrogen species is still unknown. Employing a rutile TiO2(110) surface as a model catalyst we report here for the first time the direct observation of photocatalytic H2 production under ultrahigh vacuum conditions during UV-light irradiation at 115 K and the identification of n...
Soil erosion and sand movement is one of environmental threats of the desert areas and vegetation partially prevents the creation of this phenomenon. One of the most important species growing in Sabzevar desert plains and sandy dunes, regarding too dense canopy and their root density, which have a considerable impact on soil protection and prevent movement of sands, is Stipagrostis pennata. ...
while our knowledge of anuran embryonic and larval surface ciliation and their diversity ofciliation patterns are significant, very few references were noticed on embryonic ciliation in direct-developinganurans, such as species in the genus eleutherodactylus. eleutherodactylus urichi embryos were found tohave surface ciliated cells during much of their development until a few days before hatchi...
The aim of this research was to determine the effects of Camphorosma monspeliaca species on soil variables in its habitat. Ecological positive or negative effects of new species on environment must carefully be examined before allowing their plantation in vast areas on the other hand these species with their special characteristics have special effects on their surrounding environment that sho...
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