1,307 research outputs found
Who is going to save us now? Bureaucrats, Politicians and Risky Tasks
The paper compares the policy choices regarding risk-transfer against low-probability-high-loss events between elected and appointed public officials. Empirical evidence using data on U.S. municipality-level shows that appointed city managers are more likely to adopt federal risk-transfer regimes. It is argued that the variation in the level of insurance activity emerges from the different incentive schemes each government form is facing. Controlling for spatial dependencies further shows that the participation decision in the insurance program significantly depends on the decision of neighboring communities.Politicians, bureaucrats, decision making under uncertainty, flood insurance, spatial econometrics
Influence of monolayer contamination on electric-field-noise heating in ion traps
Electric field noise is a hinderance to the assembly of large scale quantum
computers based on entangled trapped ions. Apart from ubiquitous technical
noise sources, experimental studies of trapped ion heating have revealed
additional limiting contributions to this noise, originating from atomic
processes on the electrode surfaces. In a recent work [A. Safavi-Naini et al.,
Phys. Rev. A 84, 023412 (2011)] we described a microscopic model for this
excess electric field noise, which points a way towards a more systematic
understanding of surface adsorbates as progenitors of electric field jitter
noise. Here, we address the impact of surface monolayer contamination on
adsorbate induced noise processes. By using exact numerical calculations for H
and N atomic monolayers on an Au(111) surface representing opposite extremes of
physisorption and chemisorption, we show that an additional monolayer can
significantly affect the noise power spectrum and either enhance or suppress
the resulting heating rates.Comment: 8 pages, 5 figure
First-Principles Structural, Mechanical, and Thermodynamic Calculations of the Negative Thermal Expansion Compound Zr2(WO4)(PO4)2
The negative thermal expansion (NTE) material Zr2(WO4)(PO4)2 has been investigated for the first time within the framework of the density functional perturbation theory (DFPT). The structural, mechanical, and thermodynamic properties of this material have been predicted using the Perdew, Burke and Ernzerhof for solid (PBEsol) exchangeâcorrelation functional, which showed superior accuracy over standard functionals in previous computational studies of the NTE material α-ZrW2O8. The bulk modulus calculated for Zr2(WO4)(PO4)2 using the Vinet equation of state at room temperature is K0 = 63.6 GPa, which is in close agreement with the experimental estimate of 61.3(8) at T = 296 K. The computed mean linear coefficient of thermal expansion is â3.1 Ă 10â6 Kâ1 in the temperature range âŒ0â70 K, in line with the X-ray diffraction measurements. The mean GrĂŒneisen parameter controlling the thermal expansion of Zr2(WO4)(PO4)2 is negative below 205 K, with a minimum of â2.1 at 10 K. The calculated standard molar heat capacity and entropy are CP0 = 287.6 and S0 = 321.9 J·molâ1·Kâ1, respectively. The results reported in this study demonstrate the accuracy of DFPT/PBEsol for assessing or predicting the relationship between structural and thermomechanical properties of NTE materials
Allergic and immunological aspects of therapy with cefotaxime and other cephalosporins
Immunogenicity and allergenicity studies in rodents show that cefotaxime and cefur-oxime are less immunogenic than benzylpenicillin or the semisynthetic penicillins. Cross-reactions of these antibiotics with benzylpenicilloyl-specific animal and human IgE antibodies appear minimal. Some cross-reactivity at the level of cell-mediated allergic reactions may, however, be expecte
Electric-field noise from carbon-adatom diffusion on a Au(110) surface: first-principles calculations and experiments
The decoherence of trapped-ion quantum gates due to heating of their motional
modes is a fundamental science and engineering problem. This heating is
attributed to electric-field noise arising from the trap-electrode surfaces. In
this work, we investigate the source of this noise by focusing on the diffusion
of carbon-containing adsorbates on the surface of Au(110). We show by density
functional theory, based on detailed scanning probe microscopy, how the carbon
adatom diffusion on the gold surface changes the energy landscape, and how the
adatom dipole moment varies with the diffusive motion. A simple model for the
diffusion noise, which varies quadratically with the variation of the dipole
moment, qualitatively reproduces the measured noise spectrum, and the estimate
of the noise spectral density is in accord with measured values.Comment: 8 pages, 6 figure
Molecular line opacity of LiCl in the mid-infrared spectra of brown dwarfs
We present a complete line list for the X 1Sigma+ electronic ground state of
LiCl computed using fully quantum-mechanical techniques. This list includes
transition energies and oscillator strengths in the spectral region
0.3-39,640.7 cm-1 for all allowed rovibrational transitions in absorption
within the electronic ground state. The calculations were performed using an
accurate hybrid potential constructed from a spectral inversion fit of
experimental data and from recent multi-reference single- and double-excitation
configuration interaction calculations. The line list was incorporated into the
stellar atmosphere code PHOENIX to compute spectra for a range of young to old
T dwarf models. The possibility of observing a signature of LiCl in absorption
near 15.8 microns is addressed and the proposal to use this feature to estimate
the total lithium elemental abundance for these cool objects is discussed.Comment: 8 pages, 2 figures, 1 table. Accepted for publication in ApJ 613,
Sept. 20 200
Co-designing the knowledge management model
This work-in-progress study reviews co-designing processes through the lens of possibility-driven design (PDD). A knowledge management model (KMM) is co-designed by facilitating the development work of senior and regional innovation actors who share ideas, experience and information in the development of smart products and services for an age-friendly smart living environment. The empirical part is divided into three stages: an orientation workshop, two panel meetings and three co-design and validation workshops where an appropriate knowledge management model is co-designed through iteration rounds. The first stage maps the regional innovation actors, relevant organisations in the region and data flows between all the parties. Ideas of suitable ways to manage knowledge are gathered from the panel meetings of the second stage and are methodologically supported by the strategic options development and analysis (SODA) approach. At the time of writing this paper, the third stage consisting of three workshops with appropriate iteration rounds is on-going. The findings of the study provide insights regarding the use of PDD activities with an inclusion of the SODA approach when facilitating the co-design of a KMM with a multi-professional group of experts. The study contributes to the theory of PDD by integrating systematic methodological aspects to it when working on complex problems.info:eu-repo/semantics/publishedVersio
Method for Rapid Interplanetary Trajectory Analysis using ÎV Maps with Flyby Options
This paper develops a convenient tool which is capable of calculating ballistic interplanetary trajectories with planetary flyby options to create exhaustive V contour plots for both direct trajectories without flybys and flyby trajectories in a single chart. The contours of V for a range of departure dates (x-axis) and times of flight (y-axis) serve as a âvisual calendarâ of launch windows, which are useful for the creation of a long-term transportation schedule for mission planning purposes. For planetary flybys, a simple powered flyby manoeuvre with a reasonably small velocity impulse at periapsis is allowed to expand the flyby mission windows. The procedure of creating a V contour plot for direct trajectories is a straightforward full- factorial computation with two input variables of departure and arrival dates solving Lambert's problem for each combination. For flyby trajectories, a âpseudo full-factorialâ computation is conducted by decomposing the problem into two separate full- factorial computations. Mars missions including Venus flyby opportunities are used to illustrate the application of this model for the 2020-2040 time frame. The âcompetitivenessâ of launch windows is defined and determined for each launch opportunity
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