14,893 research outputs found
On income tax avoidance: the case of Germany
In this paper, we present a micro estimate determining taxable income as a function of gross income and all major deduction options depending on household and asset categories. It is shown that tax savings strongly increase with increasing income, resulting in a decreasing effective marginal tax rate for the highest income groups. We compute a lower bound on 1983 aggregate income tax losses to the German fiscal authorities of DM 72b, or of 45 % of wage and income taxes paid in 1983. The estimate of tax loss exceeds estimates for other countries by orders of magnitude. --
Wheel–rail contact: experimental study of the creep forces–creepage relationships
The wheel–rail contact problem plays an important role in the simulation methods used to solve railway dynamics problems. As a consequence, many different mathematical models have been developed to calculate wheel–rail contact forces. However, most of them tackle this problem purely from a theoretical point of view and need to be experimentally validated. Such validation could also reveal the influence of certain parameters not taken into account in the mathematical developments. This paper presents the steps followed in building a scaled test-bench to experimentally characterise the wheel–rail contact problem. The results of the longitudinal contact force as a function of the longitudinal creepage are obtained and the divergences with respect to Kalker's simplified theory are analysed. The influence of lateral creepage, angular velocity and certain contaminants such as cutting fluid or high positive friction modifier is also discussed
Interpretation of transverse tune spectra in a heavy-ion synchrotron at high intensities
Two different tune measurement systems have been installed in the GSI
heavy-ion synchrotron SIS-18. Tune spectra are obtained with high accuracy
using these fast and sensitive systems. Besides the machine tune, the spectra
contain information about the intensity dependent coherent tune shift and the
incoherent space charge tune shift. The space charge tune shift is derived from
a fit of the observed shifted positions of the synchrotron satellites to an
analytic expression for the head-tail eigenmodes with space charge.
Furthermore, the chromaticity is extracted from the measured head-tail mode
structure. The results of the measurements provide experimental evidence of the
importance of space charge effects and head-tail modes for the interpretation
of transverse beam signals at high intensity
In the Shadow of the Pines
https://digitalcommons.library.umaine.edu/mmb-vp/1882/thumbnail.jp
Domain and Geometry Agnostic CNNs for Left Atrium Segmentation in 3D Ultrasound
Segmentation of the left atrium and deriving its size can help to predict and
detect various cardiovascular conditions. Automation of this process in 3D
Ultrasound image data is desirable, since manual delineations are
time-consuming, challenging and observer-dependent. Convolutional neural
networks have made improvements in computer vision and in medical image
analysis. They have successfully been applied to segmentation tasks and were
extended to work on volumetric data. In this paper we introduce a combined
deep-learning based approach on volumetric segmentation in Ultrasound
acquisitions with incorporation of prior knowledge about left atrial shape and
imaging device. The results show, that including a shape prior helps the domain
adaptation and the accuracy of segmentation is further increased with
adversarial learning
Persistent X-Ray Photoconductivity and Percolation of Metallic Clusters in Charge-Ordered Manganites
Charge-ordered manganites of composition exhibit persistent photoconductivity upon
exposure to x-rays. This is not always accompanied by a significant increase in
the {\it number} of conduction electrons as predicted by conventional models of
persistent photoconductivity. An analysis of the x-ray diffraction patterns and
current-voltage characteristics shows that x-ray illumination results in a
microscopically phase separated state in which charge-ordered insulating
regions provide barriers against charge transport between metallic clusters.
The dominant effect of x-ray illumination is to enhance the electron {\it
mobility} by lowering or removing these barriers. A mechanism based on magnetic
degrees of freedom is proposed.Comment: 8 pages, 4 figure
The magnetic environment in the central region of nearby galaxies
The central regions of galaxies harbor some of the most extreme physical
phenomena, including dense stellar clusters, non-circular motions of molecular
clouds and strong and pervasive magnetic field structures. In particular, radio
observations have shown that the central few hundred parsecs of our Galaxy has
a striking magnetic field configuration. It is not yet clear whether these
magnetic structures are unique to our Milky Way or a common feature of all
similar galaxies. Therefore, we report on (a) a new radio polarimetric survey
of the central 200 pc of the Galaxy to better characterize the magnetic field
structure and (b) a search for large-scale and organized magnetized structure
in the nuclear regions of nearby galaxies using data from the Very Large Array
(VLA) archive. The high angular resolution of the VLA allows us to study the
central 1 kpc of the nearest galaxies to search for magnetized nuclear features
similar to what is detected in our own Galactic center. Such magnetic features
play a important role in the nuclear regions of galaxies in terms of gas
transport and the physical conditions of the interstellar medium in this
unusual region of galaxies.Comment: 8 pages; Proceedings for "The Universe under the Microscope" (AHAR
2008), held in Bad Honnef (Germany) in April 2008, to be published in Journal
of Physics: Conference Series by Institute of Physics Publishing, R.
Schoedel, A. Eckart, S. Pfalzner, and E. Ros (eds.
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