10,846 research outputs found
Warp-speed adaptation to novel hosts after 300 generations of enforced dietary specialisation in the seed beetle Callosobruchus maculatus (Coleoptera: Chrysomelidae: Bruchinae)
Thank you to Paul Eady for providing C. maculatus to initiate our laboratory population and advice on rearing them. The study was funded by the University of Aberdeen core teaching funds (honours project budget to TP), and by a doctoral training grant to AL from the BBSRC-EastBio doctoral training partnershipPeer reviewedPublisher PD
Frequency-dependent and correlational selection pressures have conflicting consequences for assortative mating in a color-polymorphic lizard, Uta stansburiana
Acknowledgments We would like to thank the numerous undergraduate researchers involved with this project for their invaluable assistance in lizard rearing and data collection. We also thank D. Haisten, A. Runemark, Y. Takahashi, and M. Verzijden for insightful comments on the manuscript. This project was funded by National Science Foundation DEBOS-15973 to A.G.M. and B.R.S.Peer reviewedPublisher PD
Long-run Patterns of Labour Market Polarisation: Evidence from German Micro Data
The past four decades have witnessed dramatic changes in the structure of employment. In particular, the rapid increase in computational power has led to large-scale reductions in employment in jobs that can be described as intensive in routine tasks. These jobs have been shown to be concentrated in middle skill occupations. A large literature on labour market polarisation characterises and measures these processes at an aggregate level. How- ever to date there is little information regarding the individual worker adjustment processes related to routine- biased technological change. Using an administrative panel data set for Germany, we follow workers over an ex- tended period of time and provide evidence of both the short-term adjustment process and medium-run effects of routine task intensive job loss at an individual level. We initially demonstrate a marked, and steady, shift in em- ployment away from routine, middle-skill, occupations. In subsequent analysis, we demonstrate how exposure to jobs with higher routine task content is associated with a reduced likelihood of being in employment in both the short term (after one year) and medium term (five years). This employment penalty to routineness of work has increased over the past four decades. More generally, we demonstrate that routine task work is associated with reduced job stability and more likelihood of experiencing periods of unemployment. However, these negative ef- fects of routine work appear to be concentrated in increased employment to employment, and employment to unemployment transitions rather than longer periods of unemployment
Search for long lived charged massive particles in pp collisions at s-hat = 1.8TeV
We report a search for the production of long-lived charged massive particles in a data sample of 90 pb-1 of √s=1.8 TeV pp̅ collisions recorded by the Collider Detector at Fermilab. The search uses the muonlike penetration and anomalously high ionization energy loss signature expected for such a particle to discriminate it from backgrounds. The data are found to agree with background expectations, and cross section limits of O(1) pb are derived using two reference models, a stable quark and a stable scalar lepton
Statistical properties of classical gravitating particles in (2+1) dimensions
We report the statistical properties of classical particles in (2+1) gravity
as resulting from numerical simulations. Only particle momenta have been taken
into account. In the range of total momentum where thermal equilibrium is
reached, the distribution function and the corresponding Boltzmann entropy are
computed. In the presence of large gravity effects, different extensions of the
temperature turn out to be inequivalent, the distribution function has a power
law high-energy tail and the entropy as a function of the internal energy
presents a flex. When the energy approaches the open universe limit, the
entropy and the mean value of the particle kinetic energy seem to diverge.Comment: Latex2e (amssymb) file, 17 page
Evidence for magnetic clusters in NiV close to the quantum critical concentration
The d-metal alloy NiV undergoes a quantum phase transition from
a ferromagnetic ground state to a paramagnetic ground state as the vanadium
concentration is increased. We present magnetization, ac-susceptibility and
muon-spin relaxation data at several vanadium concentrations near the critical
concentration at which the onset of ferromagnetic order is
suppressed to zero temperature. Below , the muon data reveal a broad
magnetic field distribution indicative of long-range ordered ferromagnetic
state with spatial disorder. We show evidence of magnetic clusters in the
ferromagnetic phase and close to the phase boundary in this disordered
itinerant system as an important generic ingredient of a disordered quantum
phase transition. In contrast, the temperature dependence of the magnetic
susceptibility above is best described in terms of a magnetic quantum
Griffiths phase with a power-law distribution of fluctuation rates of dynamic
magnetic clusters. At the lowest temperatures, the onset of a short-range
ordered cluster-glass phase is recognized by an increase in the muon
depolarization in transverse fields and maxima in ac-susceptibility.Comment: 6 pages, 5 figures, submitted to Proceedings of SCES 201
- …
