On the domain of the assembly map in algebraic K-theory

We compare the domain of the assembly map in algebraic K-theory with respect to the family of finite subgroups with the domain of the assembly map with respect to the family of virtually cyclic subgroups and prove that the former is a direct summand of the later.Comment: Published by Algebraic and Geometric Topology at http://www.maths.warwick.ac.uk/agt/AGTVol3/agt-3-35.abs.htm

Offset frequency dynamics and phase noise properties of a self-referenced 10 GHz Ti:sapphire frequency comb

This paper shows the experimental details of the stabilization scheme that allows full control of the repetition rate and the carrier-envelope offset frequency of a 10 GHz frequency comb based on a femtosecond Ti:sapphire laser. Octave-spanning spectra are produced in nonlinear microstructured optical fiber, in spite of the reduced peak power associated with the 10 GHz repetition rate. Improved stability of the broadened spectrum is obtained by temperature-stabilization of the nonlinear optical fiber. The carrier-envelope offset frequency and the repetition rate are simultaneously frequency stabilized, and their short- and long-term stabilities are characterized. We also measure the transfer of amplitude noise of the pump source to phase noise on the offset frequency and verify an increased sensitivity of the offset frequency to pump power modulation compared to systems with lower repetition rate. Finally, we discuss merits of this 10 GHz system for the generation of low-phase-noise microwaves

Bayesian Model Comparison and Analysis of the Galactic Disk Population of Gamma-Ray Millisecond Pulsars

Pulsed emission from almost one hundred millisecond pulsars (MSPs) has been detected in $\gamma$-rays by the Fermi Large-Area Telescope. The global properties of this population remain relatively unconstrained despite many attempts to model their spatial and luminosity distributions. We perform here a self-consistent Bayesian analysis of both the spatial distribution and luminosity function simultaneously. Distance uncertainties, arising from errors in the parallax measurement or Galactic electron-density model, are marginalized over. We provide a public Python package for calculating distance uncertainties to pulsars derived using the dispersion measure by accounting for the uncertainties in Galactic electron-density model YMW16. Finally, we use multiple parameterizations for the MSP population and perform Bayesian model comparison, finding that a broken power law luminosity function with Lorimer spatial profile are preferred over multiple other parameterizations used in the past. The best-fit spatial distribution and number of $\gamma$-ray MSPs is consistent with results for the radio population of MSPs.Comment: 13 pages, 8 figures, 3 tables + Appendix. Public code and source list available from http://github.com/tedwards2412/MSPDis

Next-leading BFKL effects in forward-jet production at HERA

We show that next-leading logarithmic (NLL) Balitsky-Fadin-Kuraev-Lipatov (BFKL) effects can be tested by the forward-jet cross sections recently measured at HERA. For d\sigma/dx, the NLL corrections are small which confirms the stability of the BFKL description. The triple differential cross section d\sigma/dxdk_T^2dQ^2 is sensitive to NLL effects and opens the way for an experimental test of the full BFKL theoretical framework at NLL accuracy.Comment: 5 pages, 4 figures, NLL-BFKL saddle-point approximation now compared with exact integration, version to appear in PL

Silicon solar cell development for low temperature and low illumination intensity operation, volume 1 Analysis report, 30 Jun. 1969 - 30 Apr. 1970

Operational performance of solar cell at low temperatures and under low illumination intensit

Probabilistic Linear Solvers: A Unifying View

Several recent works have developed a new, probabilistic interpretation for numerical algorithms solving linear systems in which the solution is inferred in a Bayesian framework, either directly or by inferring the unknown action of the matrix inverse. These approaches have typically focused on replicating the behavior of the conjugate gradient method as a prototypical iterative method. In this work surprisingly general conditions for equivalence of these disparate methods are presented. We also describe connections between probabilistic linear solvers and projection methods for linear systems, providing a probabilistic interpretation of a far more general class of iterative methods. In particular, this provides such an interpretation of the generalised minimum residual method. A probabilistic view of preconditioning is also introduced. These developments unify the literature on probabilistic linear solvers, and provide foundational connections to the literature on iterative solvers for linear systems

Colored Spin Systems, BKP Evolution and finite N_c effects

Even within the framework of the leading logarithmic approximation the eigenvalues of the BKP kernel for states of more than three reggeized gluons are unknown in general, contrary to the planar limit case where the problem becomes integrable. We consider a 4-gluon kernel for a finite number of colors and define some simple toy models for the configuration space dynamics, which are directly solvable with group theoretical methods. Then we study the dependence of the spectrum of these models with respect to the number of colors and make comparisons with the large limit case.Comment: 17 pages, 4 figures, references update, to appear on EPJ

The Role of Allelopathy on the Vegetational Composition of Disturbed Sites on the Samuel H. Ordway Memorial Prairie

The presence of large numbers of cattle in prairie sites can lead to the trampling and destruction of native vegetation in some areas. These damaged, or disturbed sites are typically invaded by a variety of undesirable alien plant species. Many of the alien plant species possess allopathic mechanisms. These allopathic mechanisms enable the alien species to dominate the disturbed sites, and prevent the re-establishment of native plant species. Attempts are currently underway to preserve remaining tracts of native prairie in South Dakota. The Samuel H. Ordway, Jr. Memorial Prairie in McPherson county is one such tract, and is the research site of this study. The tall and mid-grass prairies of the eastern Dakotas were historically maintained by grazing pressure and periodic fires. The primary management tool used at Ordway Prairie is limited grazing with cattle to simulate native herbivore grazing pressures. Burning is not currently a significant management tool. This research was conducted to identify the presence and distribution of allelopathic alien species in disturbed sites resulting from overgrazing by cattle Ordway Prairie. Recommendations will be made regarding management techniques designed to reduce the dominance of disturbed sites by alien species