24 research outputs found
Differential growth of the northern Tibetan margin: evidence for oblique stepwise rise of the Tibetan Plateau
Fine-scale population genetic structure and sex-biased dispersal in the smooth snake (Coronella austriaca) in southern England
Human-induced alteration of natural habitats has the potential to impact on the genetic structuring of remnant populations at multiple spatial scales. Species from higher trophic levels, such as snakes, are expected to be particularly susceptible to land-use changes. We examined fine-scale population structure and looked for evidence of sex-biased dispersal in smooth snakes (Coronella austriaca), sampled from 10 heathland localities situated within a managed coniferous forest in Dorset, United Kingdom. Despite the limited distances between heathland areas (maximum <6 km), there was a small but significant structuring of populations based on eight microsatellite loci. This followed an isolation-by-distance model using both straight line and ‘biological’ distances between sampling sites, suggesting C. austriaca's low vagility as the causal factor, rather than closed canopy conifer forest exerting an effect as a barrier to dispersal. Within population comparisons of male and female snakes showed evidence for sex-biased dispersal, with three of four analyses finding significantly higher dispersal in males than in females. We suggest that the fine-scale spatial genetic structuring and sex-biased dispersal have important implications for the conservation of C. austriaca, and highlight the value of heathland areas within commercial conifer plantations with regards to their future management
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Measurement of the beam-normal single-spin asymmetry for elastic electron scattering from C12 and Al27
We report measurements of the parity-conserving beam-normal single-spin
elastic scattering asymmetries on C and Al, obtained with
an electron beam polarized transverse to its momentum direction. These
measurements add an additional kinematic point to a series of previous
measurements of on C and provide a first measurement on Al.
The experiment utilized the Qweak apparatus at Jefferson Lab with a beam energy
of 1.158 GeV. The average lab scattering angle for both targets was 7.7
degrees, and the average for both targets was 0.02437 GeV (Q=0.1561
GeV). The asymmetries are = -10.68 0.90 stat) 0.57 (syst) ppm
for C and = -12.16 0.58 (stat) 0.62 (syst) ppm for
Al. The results are consistent with theoretical predictions, and are
compared to existing data. When scaled by Z/A, the Q-dependence of all the
far-forward angle (theta < 10 degrees) data from H to Al can be
described by the same slope out to GeV. Larger-angle data from
other experiments in the same Q range are consistent with a slope about twice
as steep