Search results for "CLASSIFICATION"
showing 10 items of 29475 documents
Allium aetnense (Amaryllidaceae), a new species from Sicily.
2013
A new species from Mt Etna (Sicily), Allium aetenense of A. sect. Codonoprasum, is described and illustrated. It is a diploid species (2n = 16) that grows on basaltic rocks in the mountain belt and shows close relationships with A. tenuiflorum of the Italian peninsula. Its morphology, karyology, leaf anatomy, seed coat microsculpturing, ecology and taxonomic position are examined.
Detection of stationary objects by the blind Cave FishAnoptichthys jordani (Characidae)
1981
It was noticed that the blind Mexican Cave Fish repeatedly passes along objects new to it at a short distance. Observations and experiments are reported which support the hypothesis that water movements occurring between the stationary object and the fish as it passes by convey information about the location and possibly the shape of the object, which is detected by the lateral line organ of the fish. Water movements of the expected type were recorded with the help of a model fish equipped with a mechano-electric analogue of a free neuromast.
Stability and endemicity of benthic diatom assemblages from different substrates in a maritime stream on Byers Peninsula, Livingston Island, Antarcti…
2013
16 páginas, 3 tablas, 9 figuras.
The Coastal Levantine Area
2017
The Coastal Levantine area is a very diverse territory situated between the Cap de Creus and the Cap de la Nau. The wide variety of environments and ecological conditions that occur in this area determine its great diversity and richness from the vegetation point of view. Forest composition depends mainly on climatic factors, geomorphology and soil features, and are currently dominated by evergreen sclerophyllous (Quercus ilex, Q. rotundifolia, Q. suber), conifer (Pinus halepensis, P. pinaster, P. pinea, P. salzmannii, P. sylvestris), and deciduous (Fagus sylvatica, Quercus petraea) and semi-deciduous (Quercus faginea, Q. canariensis, Q. pubescens, Q. pyrenaica) species in inland areas with…
Dendropoma lower intertidal reef formations and their palaeoclimatological significance, NW Sicily
1999
Abstract Most carbonate rocky shores of NW Sicily are marked by a coalescence of shells of the gastropod Dendropoma in a construction that is variably developed as a response to wave impact. Here, we review all the available information on these constructions and find that the fossil reefs are reliable sea-level indicators. The thickness of the reef samples never exceeds 30–40 cm below sea-level, whereas all 14 C dates fall within a range of few centuries. Some small fragments ejected by violent sea storms date back to 2500 years cal BP. No samples older than 6200 years cal BP have been detected so far. The present distribution of Mediterranean vermetid platforms should result from a northw…
Terpenoid composition and origin of amber from the Cape York Peninsula, Australia
2014
The terpenoid composition of fossil resin from the Cape York Peninsula, Australia has been analysed by pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) to determine its origin. The pyrolysis products were dominated by cadalene-based C15 bicyclic sesquiterpenoids including some C30–C31 bicadinanes and bicadinenes typical of Class II resin derived from angiosperm plants of Dipterocarpaceae. This observation contrasts with the Araucariaceae (Agathis sp.) source previously suggested for the resin based on Fourier transform infrared (FTIR) analyses. Dipterocarpaceae are not known in Australian vegetation but grow abundantly in Southeast Asia including New Guinea, indicating that the geo…
Some Considerations on 3-D and 2-D Numerical Models for the Assessment of the Stability of Underground Caves
2014
The application of numerical modeling to the analysis of the stability of both natural and man-made underground caves is rapidly increasing due to the availability of powerful numerical codes, that can account for either continuum or discontinuum behavior of the rock masses. Numerical methods allow to overcome traditional methods for cave stability analysis that assume too simplified geometrical, geological and geomechanical conditions. Further, they are also able to assess the potential failure mechanisms of underground systems. On the other hand, the application of numerical methods requires availability of a detailed geo-structural survey of the cave, as well as a proper geomechanical ch…
Environmental evidence of Valencia lagoon coastal barrier stabilization from 8500 BP to Present. Climate and eustatic variations
2020
Abstract The Albufera de Valencia is one of the largest lagoon in the Spanish Mediterranean. Two continuous borehole cores reaching depths of 8 and 14 m in the northern part of the lagoon underwent sedimentological, micropaleontological and biological study. The organic content was also analysed, and 14C radiometric dating and amino acid racemization were performed. Study of the content of benthic foraminifera and n-alkanes and alkanoic acids in the lagoon sedimentary record identified several periods. The core records showed seven different environments: alluvial; freshwater marsh; brackish marsh; brackish lagoon; brackish lagoon with marine connection, backbarrier flat, and backshore. The…
Genetic Diversity of White Clover (Trifolium Repens L.) from the Urban Area of Rīga Baltā Āboliņa (Trifolium Repens L.) Ģenētiskā Daudzveidība Rīgas …
2015
Baltais āboliņš (Trifolium repens L.) ir tauriņziežu dzimtas augs, plaši izplatīts gan pilsētvidē, gan ārpus tās. Tas tiek izmantots kā lauksaimniecības augs biomasas iegūšanai, un tā ir arī populāra daudzgadīgos zālienus veidojošā suga - pilsētvidē balto āboliņu sēj zālājos. Baltais āboliņš plaši pārstāvēts dažādos biotopos ar mainīgu ārējo faktoru ietekmi, tai skaitā pilsētvidē. Tādēļ tas ir piemērots modeļobjekts antropogēnās ietekmes pētīšanai. Darba mērķis bija noteikt baltā āboliņa Latvijas populācijas ģenētisko daudzveidību, izmantojot iPBS (inter primer binding sites) - uz retrotranspazoniem balstītu metodi. Iegūtie rezultāti salīdzināti starp trim augu paraugkopām: pilsētvidē augoš…
HERPETOFAUNA DI HUTAN DATARAN RENDAH HAYA, MAMBERAMO, PAPUA
2008
<p><em>During about 19 days field work survey (7-25 February 2008) on the Haya lowland forest area, Mamberamo Papua. Eksploration is the methods used in this study. Reptiles and amphibians were collected by hand on the night and day in several type of habitat (plains, swamp, oxbowlake, stream, creeks and hills). The result showed that 48 species of herpetofauna (21 species frogs, 19 species of lizard, six species of snakes and one species of turtles and crocodile) were found.</em></p>