Search results for "Cave"
showing 10 items of 606 documents
The use of shallow dripwater as an isotopic marker of seepage in karst areas: A comparison between Western Sicily (Italy) and the Harz Mountains (Ger…
2013
Abstract The isotopic signature of slow-flowing dripwater collected in caves located in Western Sicily (Italy) was determined for evaluating its possible use as an isotopic tracer of the local groundwater recharge. These spot measures were compared with a longer series of local rain and spring compositions and with other samples taken, under different hydrogeological conditions, in caves of the Harz Mountains (Northern Germany). The slow flowing dripwater from Sicily showed δ 18 O/δD ratios similar to those of local rain and groundwater, demonstrating that these three are all parent waters. A parallel similarity was found in the vertical isotopic gradient (Δδ 18 O) of the three groups of wa…
Cueva de El Toro (Antequera, Malaga-Spain): a Neolithic stockbreeding community in the Andalusian region, between the 6th and 3th millennia BC
2004
The occupation evidence shown by the cave El Toro, is that of a unique stockbreeding community in the Andalusian region. The calibrated dates for this occupation period go from the second quarter of the sixth millennium up to the second millennium BP. There is also evidence of occasional occupation throughout later millennia up to the Hispano-Muslim period. The nature of thisoccupation is determined by the close link between the cave and the community which occupied it, both continuously and periodically. Throughout the occupation levels, the community's skillful control of technical processesand its remarkable knowledge on how to transform local primary resources, have shown that this comm…
Chemical Composition and Free Radical Scavenging Activity of the Essential Oil of Achillea ligustica Growing Wild in Lipari (Aeolian Islands, Sicily)
2013
In the present study the chemical composition of the essential oils from aerial parts and flowers of Achillea ligustica All., collected in Lipari (Aeolian Islands) was evaluated by GC and GC-MS. ( Z)-Chrysanthenyl acetate was the most abundant component of both oils (29.6% in A1 and 27.8% in F1), followed by viridiflorol (16.8% in A1 and 21.6% in F1), bornyl acetate (8.7% in A1 and 11.6% in F1) and 1,8-cineole (7.4% in A1 and 9.3% in F1). A comparison was made of the composition of the different populations studied so far. Futhermore, the free radical scavenging activity of the oil was determined by DPPH and ABTS methods.
Studies on the effects of Ca2++ and Co++ on the swimming behavior of the blind Mexican cave fish
1992
The hypothesis that the blind cave fish (Astyanax hubbsi) adjusts the level of stimulation to its lateral line system (LLS) by varying its own velocity was examined. When the sensitivity of the LLS sense organs was reduced by lowering the Ca2+ concentration in the water or by adding Co2+ the fish compensated for this by swimming at a higher velocity.
The Forebrain of the Blind Cave Fish <i>Astyanax hubbsi </i>(Characidae)
1997
This paper presents a survey of the cell groups in the telencephalon of the teleost Astyanax hubbsi, based on series of transverse sections stained with the Nissl-, Kluver-Barrera and Bodian procedure
On the discrimination of spatial intervals by the blind cave fish (Anoptichthys jordani).
1986
The performance of the blind cave fish in discriminating spatial intervals was investigated. The fish had to discriminate between pairs of grids consisting of equidistant vertical bars. The intervals between the bars on the grid to be chosen were kept constant while the intervals between the bars on the other grid were altered in steps so as to become gradually closer to the interval between the bars on the grid to be chosen. It was found that the fish were still able to discriminate between the two grids when the difference between the bar intervals amounted to at least 1.5 mm. In interpreting the results it was concluded that the phase information in the stimulus on the skin of the fish m…
Learning and remembering the environment in the blind cave fishAnoptichthys jordani
1989
1. The swimming behavior of blind cave fish (Anoptichthys jordani) differs in familiar and unfamiliar surroundings. Following release in unfamiliar surroundings, or after alterations of a familiar environment, the fish increase swimming velocity in order to optimize lateral line organ stimulation. Furthermore, they glide along boundary features more often than they do in familiar surroundings. These characteristics of swimming behavior were used to measure the occurrence and duration of exploratory behavior. 2. Fish removed from a familiar environment for as long as 2 days spend less time exploring when returned than when they were initially placed in the environment. After a longer absence…
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.
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…
The Santa Ninfa Cave (Belice Valley): hydrogeochemical features and relationships with neotectonics
2020
The Santa Ninfa Cave (SNC) develops in an outcrop of Messinian gypsum, located in the heart of the zone struck by the 1968 seismic sequence of the Belice valley. It is composed of different levels of sub-horizontal galleries, the lowest of which is characterized by perennial flowing water, running along the water table. From the hydrogeological point of view, it configures as an open circuit, both inflowing and outflowing from/to neighboring aquifers. The geochemical facies of groundwater collected in the SNC is compatible with a meteoric recharge chemically interacting with evaporitic deposits. The most relevant geochemical feature is the mixing between a small tributary of sulfur water wi…