Bimodality in the transverse fluctuations of a grafted semiflexible polymer and the diffusion-convection analogue: An effective-medium approach

Recent Monte Carlo simulations of a grafted semiflexible polymer in 1+1 dimensions have revealed a pronounced bimodal structure in the probability distribution of the transverse (bending) fluctuations of the free end, when the total contour length is of the order of the persistence length G. Lattanzi , Phys. Rev E 69, 021801 (2004)]. In this paper, we show that the emergence of bimodality is related to a similar behavior observed when a random walker is driven in the transverse direction by a certain type of shear flow. We adapt an effective-medium argument, which was first introduced in the context of the sheared random-walk problem E. Ben-Naim , Phys. Rev. A 45, 7207 (1992)], in order to obtain a simple analytic approximation of the probability distribution of the free-end fluctuations. We show that this approximation captures the bimodality and most of the qualitative features of the free-end fluctuations. We also predict that relaxing the local inextensibility constraint of the wormlike chain could lead to the disappearence of bimodality

Driven lattice gas of dimers coupled to a bulk reservoir

We investigate the non-equilibrium steady state of a one-dimensional (1D) lattice gas of dimers. The dynamics is described by a totally asymmetric exclusion process (TASEP) supplemented by attachment and detachment processes, mimicking chemical equilibrium of the 1D driven transport with the bulk reservoir. The steady-state phase diagram, current and density profiles are calculated using both a refined mean-field theory and extensive stochastic simulations. As a consequence of the on-off kinetics, a new phase coexistence region arises intervening between low and high density phases such that the discontinuous transition line of the TASEP splits into two continuous ones. The results of the mean-field theory and simulations are found to coincide. We show that the physical picture obtained in the corresponding lattice gas model with monomers is robust, in the sense that the phase diagram changes quantitatively, but the topology remains unaltered. The mechanism for phase separation is identified as generic for a wide class of driven 1D lattice gases.Comment: 15 pages, 10 figures, 1tabl

Studies of the major planet satellite systems

A summary is presented of the available data on the satellites of the major planets, including the currently most plausible models for several observed phenomena, for the planning of spacecraft missions to these objects. Some of the important questions likely to be solved by flyby and/or orbital missions to the giant planets are detailed, the importance of these studies to our understanding of the solar system as a whole is indicated

Deterrence and Morale in Taxation: An Empirical Analysis

The standard model of tax evasion based on the subjective expected utility maximization does not perform particularly well in econometric analyses: it predicts too little evasion and produces unsatisfactory econometric parameter estimates. The model is extended by looking at how the tax authority deals with the taxpayers. Based on econometric estimates, it is shown that taxpayers’ tax morale is raised when the tax officials treat them with respect. In contrast, when tax officials solely rely on deterrence taxpayers tend to respond by actively trying to avoid taxation.

High-energy laser-pulse self-compression in short gas-filled fibers

We examine the spatiotemporal compression of energetic femtosecond laser pulses within short gas-filled fibers. The study is undertaken using an advanced nonlinear pulse propagation model based on a multimode generalized nonlinear Schrödinger equation that has been modified to include plasma effects. Plasma defocusing and linear propagation effects are shown to be the dominant processes within a highly dynamical mechanism that enables 100-fs pulses to be compressed into the few-cycle regime after <50 mm of propagation. Once the mechanism has been introduced, parameter spaces are explored and compressor designs suitable for performing high-field experiments in situ are presented. We finish by showing how these designs may be extended to novel wavelengths and driving pulses delivered by state-of-the-art high-repetition-rate lasers

Illegal, Immoral, Fattening or What?: How Deterrence and Responsive Regulation Shape Tax Morale

The traditional economic approach to tax evasion does not appear to be particularly successful in explaining the extent of tax compliance. It is often argued that reciprocity norms which establish a fiscal exchange between the state and the citizens shape tax morale to a large extent. In that respect, a case study of Switzerland may be useful because the small size of the cantons and their direct democratic political systems procedurally establish a close exchange relationship between taxpayers and tax authorities. In this paper, evidence is discussed on how tax morale in Switzerland evolved over time. In addition, the impact of economic, legal, socio- demographic, psychological and institutional factors on Swiss tax evasion is analyzed. It can be concluded that Switzerland’s system of responsive regulation increases tax morale.Tax Evasion, Tax Morale, Deterrence, Responsive Regulation.

Trust Breeds Trust: How Taxpayers are Treated

Tax compliance has been studied in economics by analysing the individual decision of a representative person between paying and evading taxes. A neglected aspect of tax compliance is the interaction of taxpayers and tax authorities. The relationship between the two actors can be understood as an implicit or "psychological" contract. The more strongly the political participation rights are developed, the more important this contract is, and the higher tax morale is. In this paper, empirical evidence based on a survey of tax authorities of the 26 Swiss states (cantons) is presented, indicating that the differences in the treatment of taxpayers by tax authorities can be explained by differences in political participation rights.Tax evasion, tax authority, tax compliance, direct democracy

The use of happiness research for public policy

Research on happiness tends to follow a "benevolent dictator" approach where politicians pursue people's happiness. This paper takes an antithetic approach based on the insights of public choice theory. First, we inquire how the results of happiness research may be used to improve the choice of institutions. Second, we show that the policy approach matters for the choice of research questions and the kind of knowledge happiness research aims to provide. Third, we emphasize that there is no shortcut to an optimal policy maximizing some happiness indicator or social welfare function since governments have an incentive to manipulate this indicator

Efficient Constellation-Based Map-Merging for Semantic SLAM

Data association in SLAM is fundamentally challenging, and handling ambiguity well is crucial to achieve robust operation in real-world environments. When ambiguous measurements arise, conservatism often mandates that the measurement is discarded or a new landmark is initialized rather than risking an incorrect association. To address the inevitable `duplicate' landmarks that arise, we present an efficient map-merging framework to detect duplicate constellations of landmarks, providing a high-confidence loop-closure mechanism well-suited for object-level SLAM. This approach uses an incrementally-computable approximation of landmark uncertainty that only depends on local information in the SLAM graph, avoiding expensive recovery of the full system covariance matrix. This enables a search based on geometric consistency (GC) (rather than full joint compatibility (JC)) that inexpensively reduces the search space to a handful of `best' hypotheses. Furthermore, we reformulate the commonly-used interpretation tree to allow for more efficient integration of clique-based pairwise compatibility, accelerating the branch-and-bound max-cardinality search. Our method is demonstrated to match the performance of full JC methods at significantly-reduced computational cost, facilitating robust object-based loop-closure over large SLAM problems.Comment: Accepted to IEEE International Conference on Robotics and Automation (ICRA) 201

Probing the Active Massive Black Hole Candidate in the Center of NGC 404 with VLBI

Recently Nyland et al. (2012) argued that the radio emission observed in the center of the dwarf galaxy NGC 404 originates in a low-luminosity active galactic nucleus (LLAGN) powered by a massive black hole ($M\sim<10^6$ M$_{\odot}$). High-resolution radio detections of MBHs are rare. Here we present sensitive, contemporaneous Chandra X-ray, and very long baseline interferometry (VLBI) radio observations with the European VLBI Network (EVN). The source is detected in the X-rays, and shows no long-term variability. If the hard X-ray source is powered by accretion, the apparent low accretion efficiency would be consistent with a black hole in the hard state. Hard state black holes are known to show radio emission compact on the milliarcsecond scales. However, the central region of NGC 404 is resolved out on 10 milliarcsecond (0.15-1.5 pc) scales. Our VLBI non-detection of a compact, partially self-absorbed radio core in NGC 404 implies that either the black hole mass is smaller than $3^{+5}_{-2}\times10^5$ M$_{\odot}$, or the source does not follow the fundamental plane of black hole activity relation. An alternative explanation is that the central black hole is not in the hard state. The radio emission observed on arcsecond (tens of pc) scales may originate in nuclear star formation or extended emission due to AGN activity, although the latter would not be typical considering the structural properties of low-ionization nuclear emission-line region galaxies (LINERs) with confirmed nuclear activity.Comment: Accepted for publication in the Astrophysical Journal. 7 pages, 2 figures, 1 tabl