11,594 research outputs found
Options for a UK 'flat tax': some simple simulations
This Briefing Note analyses the effects of four possible flat tax systems for the UK: one that flattens the rate structure of income tax only, one that also flattens National Insurance contributions, and two that flatten the combined rate structure of income tax and tax credits (with and without flattening National Insurance contributions as well). In all cases, the tax base is left unchanged. The analysis is conducted for the working-age population only, and in all cases the reforms are designed to be revenue neutral under the strong assumption that people do not change their behaviour in response to the reforms. We examine the effects of the reforms on particular example families and on the overall distributions of income and work incentives
A survey of the UK tax system
This document provides an overview of the UK tax system, describing how each of the main taxes works and setting their current state into the context of the past 27 years
Impulse Generation by an Open Shock Tube
We perform experimental and numerical studies of a shock tube with an open end. The purpose is to investigate the impulse due to the exhaust of gases through the open end of the tube as a model for a partially filled detonation tube as used in pulse detonation engine testing. We study the effects of the pressure ratio (varied from 3 to 9.2) and the volume ratio (expressed as fill fractions) between the driver and driven section. Two different driver gases, helium and nitrogen, and fill fractions between 5 and 100% are studied; the driven section is filled with air. For both driver gases, increasing the pressure ratio leads to larger specific impulses. The specific impulse increases for a decreasing fill fraction for the helium driver, but the impulse is almost independent of the fill fraction for the nitrogen driver. Two-dimensional (axisymmetric) numerical simulations are carried out for both driver gases. The simulation results show reasonable agreement with experimental measurements at high pressure ratios or small fill fractions, but there are substantial discrepancies for the smallest pressure ratios studied. Empirical models for the impulse in the limits of large and small fill fractions are also compared with the data. Reasonable agreement is found for the trends with fill fractions using the Gurney or Sato model at large fill fractions, but only Cooper’s bubble model is able to predict the small fill fraction limit. Computations of acoustic impedance and numerical simulations of unsteady gas dynamics indicate that the interaction of waves with the driver-driven gas interface and the propagation of waves in the driven gas play an essential role in the partial-fill effect
The colour of the narrow line Sy1-blazar 0324+3410
Aims. We investigate the properties of the host galaxy of the blazar
J0324+3410 (B2 0321+33) by the analysis of B and R images obtained with the NOT
under good photometric conditions. Methods: The galaxy was studied using
different methods: Sersic model fitting, unsharp-masked images, B-R image and
B-R profile analysis. Results: The images show that the host galaxy has a
ring-like morphology. The B-R colour image reveals two bluish zones: one that
coincides with the nuclear region, interpreted as the signature of emission
related to the active nucleus, the other zone is extended and is located in the
host ring-structure. We discuss the hypothesis that the later is thermal
emission from a burst of star formation triggered by an interacting/merging
process
GALEX ultraviolet observations of stellar variability in the Hyades and Pleiades clusters
We present GALEX near ultraviolet (NUV:1750 - 2750A) and far ultraviolet
(FUV: 1350 - 1750A) imaging observations of two 1.2 degree diameter fields in
the Hyades and Pleiades open clusters in order to detect possible UV
variability of the member stars. We have performed a detailed software search
for short-term UV flux variability during these observations of the approx 400
sources detected in each of the Hyades and Pleiades fields to identify
flare-like (dMe) stellar objects. This search resulted in the detection of 16
UV variable sources, of which 13 can be directly associated with probable
M-type stars. The other UV sources are G-type stars and one newly discovered RR
Lyrae star, USNOB1.0 1069-0046050, of period 0.624 day and distance 4.5-7.0
kpc. Light curves of photon flux versus time are shown for 7 flare events
recorded on six probable dMe stars. UV energies for these flares span the range
2E27 to 5E29 erg, with a corresponding NUV variability change of 1.82 mag. Only
one of these flare events (on the star Cl* Melotte 25 LH129) can definitely be
associated with an origin on a member the Hyades cluster itself. Finally, many
of our M-type candidates show long periods of enhanced UV activity but without
the associated rapid increase in flux that is normally associated with a flare
event. However, the total UV energy output during such periods of increased
activity is greater than that of many short-term UV flares. These intervals of
enhanced low-level UV activity concur with the idea that, even in quiescence,
the UV emission from dMe stars may be related to a superposition of many small
flare events possessing a wide range of energies.Comment: PASP Submitte
Low emission zones: the likely effects on the freight transport sector
London’s air quality has improved over recent decades, but is still the worst in the UK. Road transport emissions play an important part in this pollution. A low emission zone (LEZ) would help to accelerate the introduction of cleaner vehicles, and reduce the numbers of older, more polluting vehicles operating in London. The survey work carried out indicates that there is support among goods vehicle operators for an LEZ in London, depending on the precise scheme definition. Operators would generally try to comply with LEZ regulations, with most companies either using technical approaches to ensure that their London vehicle fleet complied with the required emission standard or by redeploying vehicles with the appropriate emission standard from other locations
Computational power of correlations
We study the intrinsic computational power of correlations exploited in
measurement-based quantum computation. By defining a general framework the
meaning of the computational power of correlations is made precise. This leads
to a notion of resource states for measurement-based \textit{classical}
computation. Surprisingly, the Greenberger-Horne-Zeilinger and
Clauser-Horne-Shimony-Holt problems emerge as optimal examples. Our work
exposes an intriguing relationship between the violation of local realistic
models and the computational power of entangled resource states.Comment: 4 pages, 2 figures, 2 tables, v2: introduction revised and title
changed to highlight generality of established framework and results, v3:
published version with additional table I
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