Search results for "Altitude"
showing 10 items of 184 documents
Empirical study of extreme rainfall intensity in a semi-arid environment at different time scales
2014
Abstract Mediterranean environments are typical of semi-arid regions, dominated by episodes of torrential rain in which the critical variable is not the total rainfall, but the intensity. This paper studies the maximum rainfall intensities at different observation time scales, from 5 min to 24 h, over eastern Spain from 1994 to 2007. The statistical rainfall characteristics for each time scale are analysed and the effects of specific geographical factors – altitude, aspect and distance to the sea – for each observation interval are tested. The results show that extreme intensities are heavily dependent on the time scale. There are two important turning points in this trend, at 1 h and 6 h. …
Microcrustacean and Rotiferan Communities of Two Close Mediterranean Mountain Ponds, Lagunas de Bezas and Rubiales (Spain)
2010
ABSTRACT We compared two freshwater mountain ponds during an annual cycle by focusing on Rotifera and Crustacea. These ponds, Laguna de Bezas and Laguna de Rubiales, are located only 4.5 kilometers apart and share a similar altitude (ca. 1200 m.a.s.1) on the Iberian Mountain range, in Teruel (Spain). Bezas is near-permanent and dries out only in severe droughts; Rubiales is temporary, drying out periodically. They also show important differences in other limnological traits. Bezas has transparent water, harbors a fish population, and has a dense macrophyte cover, whereas Rubiales has elevated turbidity and neither fish nor macrophytes during most of the hydroperiod. These differences are pr…
Pheno-morphological and agronomic diversity among Scorpiurus muricatus (Fabaceae) natural populations collected in Sicily.
2009
SUMMARYPrickly scorpion's tail (Scorpiurus muricatus L.) is a self-reseeding annual legume widely distributed in natural pastures of the Mediterranean area and appreciated by farmers for its productivity, forage quality and palatability. Twenty-eight natural populations were collected throughout Sicily in 2005; two field experiments were carried out in 2005/06 in a hilly area of the Sicilian inland to assess the genetic variation based on pheno-morphological and agronomic characters. The pheno-morphological traits observed were analysed using a principal component analysis (PCA). The first four components of PCA (eigenvalues >1) explained 0·84 of the total variation. Similarities obtaine…
Effect of Cutting Size and Basal Heat on Rooting of Micromeria fruticulosa Stem Cuttings
2017
Micromeria fruticulosa (Bertol.) Grande is a small pulviniform shrub, belonging to the Labiates, and characterized by twisted stems and pink-purple flowers. Endemic to Campania and Sicily (Italy), M. fruticulosa grows from sea level to 600 m altitude. This specie might be considered an excellent native plant for landscape purposes in Mediterranean areas because of its long flowering period, extending from November to June, and its tolerance to heat and drought. The exploitation of wild plants for ornamental purposes implies knowledge on the factors influencing the propagation methods. Root development of stem cuttings of M. fruticulosa was investigated in relation to basal heat and cutting …
Habitat preferences of the Tawny owl (Strix aluco) in a Special Conservancy Area of eastern Spain.
2020
The Tawny Owl (Strix aluco) is the most abundant nocturnal raptor in Europe. It has been thoroughly studied in various regions, but its habitat preferences in Mediterranean environments remain poorly understood. With the aim to present novel information about this aspect of the ecology of the Tawny Owl, we established 115 survey stations in the Special Conservancy Area 'Sierras de Talayuelas y Aliaguilla' (Castilla-La Mancha region, eastern Spain) and carried out nocturnal surveys by recording spontaneous calls and vocal responses to call playbacks. We then assessed environmental characteristics (vegetation types, soil type, altitude, potential competitors, and anthropic disturbance) in are…
Soil water content assessment: Seasonal effects on the triangle method
2016
Among indirect estimations of the soil water content in the upper layer, the "triangle method" is based on the relationship between the optical and thermal features sensed via Earth Observation. These features are controlled by water content at surface and within root zone, but also by meteorological forcing including air temperature and humidity, and solar radiation. Night and day-time MODIS composite land-surface temperature (LST) allowed applying the thermal admittance version of the method; by taking into account the temporal admittance of the soil, this version was previously found achieving high accuracy in estimate the soil water content at high spatial resolution within a short time…
Structure of the altitude adapted hemoglobin of Guinea pig in the R2-state
2010
Background: Guinea pigs are considered to be genetically adapted to a high altitude environment based on the consistent finding of a high oxygen affinity of their blood. Methodology/Principal Findings: The crystal structure of guinea pig hemoglobin at 1.8 A u resolution suggests that the increased oxygen affinity of guinea pig hemoglobin can be explained by two factors, namely a decreased stability of the Tstate and an increased stability of the R2-state. The destabilization of the T-state can be related to the substitution of a highly conserved proline (P44) to histidine (H44) in the a-subunit, which causes a steric hindrance with H97 of the b-subunit in the switch region. The stabilizatio…
The map of biodiversity : from local to global scales
2018
Species richness is not homogeneous in space and it normally presents differences when comparing among different sites. These differences often respond to gradients in one or several factors which create biodiversity patterns in space and are scale-dependent. At a local scale, diversity patterns depend on the habitat size (species-area relationship), the productivity, the environmental harshness, the frequency and intensity of disturbance, or the regional species pool. Regional diversity may be influenced by environmental heterogeneity (increasing dissimilarity), although it could act also at smaller or larger spatial scales, and the connectivity among habitats. Finally, at a global scale, …
Reduction of olfactory sensitivity during normobaric hypoxia.
2018
Abstract Objective Acute mountain sickness (AMS) is caused by a low partial pressure of oxygen and may occur above 2500 m. The aim of this research was to evaluate olfactory and gustatory abilities of healthy subjects during baseline conditions and after seven hours of normobaric hypoxia. Methods Sixteen healthy subjects were assessed using the Sniffin’ Sticks, as well as intensity and pleasantness ratings. Gustatory function was evaluated utilizing the Taste Strips. Experiments were carried out under baseline conditions (518 m altitude) followed by a second testing session after seven hours of normobaric hypoxia exposure (comparable to 4000 m altitude). Results During normobaric hypoxia ol…
Fasciola hepatica phenotypic characterization in Andean human endemic areas: Valley versus altiplanic patterns analysed in liver flukes from sheep fr…
2011
Fascioliasis is a zoonotic parasitic disease caused by Fasciola hepatica and Fasciola gigantica. Of both species, F. hepatica is the only one described in the Americas, mainly transmitted by lymnaeid snail vectors of the Galba/. Fossaria group. Human fascioliasis endemic areas are mainly located in high altitude areas of Andean countries. Given the necessity to characterize F. hepatica populations involved, the phenotypic features of fasciolid adults infecting sheep present in human fascioliasis endemic areas were analysed in the Cajamarca Valley and Mantaro Valley (valley transmission patterns) and the northern Bolivian Altiplano (altiplanic transmission pattern). A computer image analysis…