Effects of impurities on Tamm-like lanthanide-metal surface states

The effects of isolated residual-gas adsorbates on the local electronic structure of the Dy(0001) surface were spatially mapped by scanning tunneling microscopy and spectroscopy at 12 K. Less than 15 A away from an adsorbate, a strong reduction of the intensity and a significant increase of the width of the majority component of the surface state due to impurity scattering were observed, with essentially no change of the minority component; this reflects a high lateral localization of the Tamm-like surface state. Furthermore, an adsorbate-induced state was found that behaves metastable.Comment: 5 pages, 4 figures, accepted as Brief Report for Physical Review

The A-theoretic Farrell–Jones conjecture for virtually solvable groups

We prove the A -theoretic Farrell–Jones conjecture for virtually solvable groups. As a corollary, we obtain that the conjecture holds for S -arithmetic groups and lattices in almost connected Lie groups

Optimization of perturbative similarity renormalization group for Hamiltonians with asymptotic freedom and bound states

A model Hamiltonian that exhibits asymptotic freedom and a bound state, is used to show on example that similarity renormalization group procedure can be tuned to improve convergence of perturbative derivation of effective Hamiltonians, through adjustment of the generator of the similarity transformation. The improvement is measured by comparing the eigenvalues of perturbatively calculated renormalized Hamiltonians that couple only a relatively small number of effective basis states, with the exact bound state energy in the model. The improved perturbative calculus leads to a few-percent accuracy in a systematic expansion.Comment: 6 pages of latex, 4 eps figure

Equations of State for Nonlinear Sigma-Models II: Relations between Resummation Schemes, and Crossover Phenomena

It is shown how a recent method to systematically extrapolate and resum the loop expansion for nonlinear sigma-models is related to solutions of the renormalization group equation. This relation is used to generalize the explicit equations of state obtained previously to models which display crossover phenomena. As an example we discuss Wegner's localization model and consider the crossover from symplectic to unitary symmetry.Comment: 14pp., REVTeX, 1 figur

On moduli of vector bundles on p-adic curves and attached representations

In der vorliegenden Arbeit wird das von Deninger/Werner entwickelte p-adische Analogon der klassischen Narasimhan-Seshadri Theorie hinsichtlich der Formulierbarkeit in den Termen der Moduli von Vektorbündeln und entsprechenden Darstellungen untersucht. Sei X eine glatte, projektive und zusammenhängende Kurve über QpBar. Einem Vektorbündel E mit stark semistabiler Reduktion auf X_Cp ordnet das étale Paralleltransport unter anderem eine stetige endlich-dimensionale Darstellung der étalen Fundamentalgruppe von X zu. Andererseits ist jedes Vektorbündel mit stark semistabiler Reduktion ebenfalls semistabil, induziert also einen Cp-wertigen Punkt in dem Modulraum M_X, der semistabile Vektorbündel von entsprechendem Rang und Grad parametrisiert. Es wird gezeigt, dass die Klasse der Vektorbündel auf X_Cp (von festem Rang und Grad), die stark semistabile Reduktion über ZpBar haben, im p-adischen Sinne eine offene Teilmenge in M_X(QpBar) induziert. Desweiteren beschreiben wir die obige Zuordnung der Darstellungen in den Termen der Moduli von Vektorbündeln sowie zugeordneten Darstellungen. Wir zeigen, dass diese unter einer technischen Voraussetzung stetig ist

Lung function decline in 4-monthly repeated spirometric measurements: Due to silt aerosol exposure or decreasing effort?

Background: Workers on dredgers and lighters on rivers are exposed to the inhalation of aerosols and dusts. Objective: The aim of this study was to investigate effects of river silt aerosol and dust exposure on the respiratory health of dredging employees. Methods: Six era mi nations were performed over a period of 2 years at 4-monthly intervals in 54 seamen with higher silt aerosol exposure and 36 controls of the same employer. Results: No significant differences could be observed between the groups at any time of the study but there was an unexpected significant decrease in the age-corrected expiratory vital capacity (FVC), forced expiratory volume in 1 s (FEV1) and midexpiratory flow rate (MMEF25/75) over the six series in both groups. This may indicate a loss of effort of the participants in re-examinations since biological and technical influences were highly unlikely to be the cause of these findings. Conclusions: Ignoring this possible decline of effort in frequently repeated measurements may result in overestimating potential effects of occupational exposure. Copyright (C) 2000 S. Karger AG, Basel

AGRICULTURAL LAND CONVERSION IN THE TWIN CITIES: PART II, THE NATIONAL RESOURCES INVENTORY

We divided the thirteen-county Twin Cities Metropolitan Statistical Area into a core and a fringe of seven and six counties, respectively. The National Resources Inventory estimates that 170 thousand acres of the Core were converted from agriculture to other uses between 1982 and 1987, while only about 46 thousand acres of the Fringe were so converted. The conversion rate was much greater in the Core than on the Fringe according to the NRIbut not according to the Census of Agriculture. The number of acres of agricultural land converted for each new resident ranged from 0.15 in Sherburne County to 2.49 in Pierce County. Viewed another way, the increase in urban land to house new residents ranged from 0.28 in Ramsey County to 1.23 acres per person in Isanti County.Land Economics/Use,