Search results for "Steppe"
showing 10 items of 71 documents
Temperature monitoring in archaeological animal bone samples in the Near East arid area, before, during and after excavation
2008
Summary In order to estimate experimentally the intensity and amplitude of thermal shocks during and after excavation, we monitored temperatures of archaeological bones on the field at three Syrian sites of the arid steppe, Qaramel, Dja'de and Aswad. Water cleaning and sun drying appear to be the most damaging steps, with temperature variations of ca. 11,000 °C/h and 84 °C/h, respectively. Ancient DNA (aDNA) bone samples kept between −7 and +12 °C from their extraction to the lab suffered much lower thermal variations (6 °C/h). Estimation of the temperature variations at different depths in the soil suggests that aDNA has suffered negative thermal conditions shortly after burial and again d…
Habitat preferences of Bonelli's Eagles Aquila fasciata in Sicily
2012
Capsule For breeding, areas dominated by extensive agricultural and rugged Mediterranean landscapes are preferred; maintenance of habitat heterogeneity and extensive agriculture are key for the conservation of this eagle. Aims To model breeding habitat preferences of Bonelli’s Eagles Aquila fasciata in Sicily, where the last viable population still remains in Italy, in order to identify the most important habitats for conservation. Methods Pairs were monitored between 1990 and 2010. A case-control design through GLMs was used at two spatial scales: landscape and home-range. Variables included topographic, climatic, land-use, road and descriptors of habitat heterogeneity. Information-based c…
Conservation genetics of endangered leaf-beetle Cheilotoma musciformis populations in Poland
2012
Steppe-like habitats in Europe are seriously threatened as a result of fragmentation and anthropogenic degradation, at least in western and central parts. Considering the dramatic loss of steppe-like habitats, the evaluation of genetic variation in populations of steppe species is of immediate importance if appropriate conservation measures are to be undertaken. In this paper, we examine the genetic diversity of the highly endangered populations of the leaf-beetle Cheilotoma musciformis, which inhabits only a limited area in south-central Poland, which is geographically isolated from the continuous range of this species. Both mitochondrial and nuclear markers show that the Polish population…
Using Y-chromosome capture enrichment to resolve haplogroup H2 shows new evidence for a two-path Neolithic expansion to Western Europe
2021
Uniparentally-inherited markers on mitochondrial DNA (mtDNA) and the non-recombining regions of the Y chromosome (NRY), have been used for the past 30 years to investigate the history of humans from a maternal and paternal perspective. Researchers have preferred mtDNA due to its abundance in the cells, and comparatively high substitution rate. Conversely, the NRY is less susceptible to back mutations and saturation, and is potentially more informative than mtDNA owing to its longer sequence length. However, due to comparatively poor NRY coverage via shotgun sequencing, and the relatively low and biased representation of Y-chromosome variants on capture assays such as the 1240 k, ancient DNA…
Diurnal habitat suitability for a Mediterranean steppeland bird, identified by Ecological Niche Factor Analysis
2011
Context The negative effects of agricultural intensification and policies, use of pesticides, fertilisers and mechanised harvesting on several populations of pseudo-steppe birds have increasingly required more detailed and effective habitat suitability models. Distribution models of farmland species are prone to incur recordings of false absence data. Ecological Niche Factor Analysis (ENFA) allows identification of environmental predictors of species distribution by using presence data only. Aims We quantified the diurnal habitat preferences and niche width of one steppe species, the stone curlew (Burhinus oedicnemus), with unfavourable conservations status in a Mediterranean area and recl…
A stepper motor-driven microelectrode positioner
1987
The mechanical elements and the electronic control system from a stepper motor-driven microelectrode positioner is described. The unit embodies a high-precision small step angle hybrid motor. The compact, rugged and totally concentric design of the mechanic, by a spindle mechanism achieves the necessary precision by translating the stepwise rotations of the motor into steps of linear movement. The system takes advantage of commercially available low friction parts such as ball bearings, ball bushings and axles with hardened surfaces. The related electronic control unit is designed around the most recent integrated circuitry which is both sophisticated and economical. Though the described sy…
Effects of Nest and Colony Features on Lesser Kestrel (Falco naumanni) Reproductive Success
2012
The Lesser Kestrel is a facultative colonial raptor mostly breeding in man-made structures. During 2009-2011 we checked the fate of 545 nests found in 18 colonies located in south-eastern Sicily. We determined the reproductive success of breeding pairs by analysing the survival time of each egg to hatching ( n = 2,495) and each nestling to fledging ( n = 1,849) with the linear hazard model of survival times. We determined whether egg and nestling survival differed between years with a Gehan–Wilcoxon test. By Cox regressions, we related the survival times with nest and colony features. Egg and nestling survival times showed a strong annual effect. The two reproductive stages of the Lesser K…
Ancestry and demography and descendants of Iron Age nomads of the Eurasian Steppe
2017
During the 1st millennium before the Common Era (BCE), nomadic tribes associated with the Iron Age Scythian culture spread over the Eurasian Steppe, covering a territory of more than 3,500 km in breadth. To understand the demographic processes behind the spread of the Scythian culture, we analysed genomic data from eight individuals and a mitochondrial dataset of 96 individuals originating in eastern and western parts of the Eurasian Steppe. Genomic inference reveals that Scythians in the east and the west of the steppe zone can best be described as a mixture of Yamnaya-related ancestry and an East Asian component. Demographic modelling suggests independent origins for eastern and western g…
Language in Central Europe: An Overview
2009
The linguistic picture of Central Europe, as we know it, started forming in the 6th to 9th centuries. The coming of the Slavs (or rather the spread of their language and way of life to unrelated various ethnic groups) marks the beginning of this caesura that largely closed in 896 AD when the Magyars crossed the Carpathians into Pannonia. This event gradually divided the hypothetically continuous area of Slavic settlement into a southern section, extending from contemporary Slovenia to Bulgaria, and into a northern section, which coincided with the areas from the Elbe in today’s eastern Germany to the upper Volga in northeastern Russia. In the west, the Magyar-speakers skirted the East and …
Daurian pikas ( Ochotona daurica ) and grassland condition in eastern Mongolia
2003
Pikas ( Ochotona spp.) are burrowing herbivorous mammals believed to play a keystone role in determining the biodiversity of steppe ecosystems. Impacts of domestic livestock grazing on the distribution and abundance of the Daurian pika Ochotona daurica were investigated in eastern Mongolia where the species is widespread and abundant. Effects of pikas on plant species richness and vegetation coverage were examined at different distances from burrow systems. Daurian pikas were nearly absent from severely grazed study sites, and incidence of the species increased with decreasing grazing intensity. The number of occupied burrow systems and usage of burrows was higher in sites with lower grazin…