7,357 research outputs found
Random point sets and their diffraction
The diffraction of various random subsets of the integer lattice
, such as the coin tossing and related systems, are well
understood. Here, we go one important step beyond and consider random point
sets in . We present several systems with an effective
stochastic interaction that still allow for explicit calculations of the
autocorrelation and the diffraction measure. We concentrate on one-dimensional
examples for illustrative purposes, and briefly indicate possible
generalisations to higher dimensions.
In particular, we discuss the stationary Poisson process in
and the renewal process on the line. The latter permits a unified approach to a
rather large class of one-dimensional structures, including random tilings.
Moreover, we present some stationary point processes that are derived from the
classical random matrix ensembles as introduced in the pioneering work of Dyson
and Ginibre. Their re-consideration from the diffraction point of view improves
the intuition on systems with randomness and mixed spectra.Comment: 9 pages, 2 figures; talk presented at ICQ 11 (Sapporo
Detecting gradual changes in locally stationary processes
In a wide range of applications, the stochastic properties of the observed
time series change over time. The changes often occur gradually rather than
abruptly: the properties are (approximately) constant for some time and then
slowly start to change. In many cases, it is of interest to locate the time
point where the properties start to vary. In contrast to the analysis of abrupt
changes, methods for detecting smooth or gradual change points are less
developed and often require strong parametric assumptions. In this paper, we
develop a fully nonparametric method to estimate a smooth change point in a
locally stationary framework. We set up a general procedure which allows us to
deal with a wide variety of stochastic properties including the mean,
(auto)covariances and higher moments. The theoretical part of the paper
establishes the convergence rate of the new estimator. In addition, we examine
its finite sample performance by means of a simulation study and illustrate the
methodology by two applications to financial return data.Comment: Published at http://dx.doi.org/10.1214/14-AOS1297 in the Annals of
Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical
Statistics (http://www.imstat.org
Terrestrial vs. spaceborne, quantum vs. classical tests of the equivalence principle
The equivalence principle can be tested by precision experiments based on
classical and quantum systems, on the ground as well as in space. In many
models, these tests are mostly equivalent in their ability to constrain physics
beyond the Standard Model. We mention differences that nevertheless exist
between spaceborne and quantum mechanical tests and their conventional
competitors.Comment: Four pages for the proceedings of the sixth meeting on CPT and
Lorentz symmetr
Financing asset growth : [version 11 august 2013]
In this paper we provide new evidence that corporate financing decisions are associated with managerial incentives to report high equity earnings. Managers rely most heavily on debt to finance their asset growth when their future earnings prospects are poor, when they are under pressure due to past declines in earnings, negative past stock returns, and excessively optimistic analyst earnings forecasts, and when the earnings yield is high relative to bond yields so that from an accounting perspective equity is ‘expensive’. Managers of high debt issuing firms are more likely to be newly appointed and also more likely to be replaced in subsequent years. Abnormal returns on portfolios formed on the basis of asset growth and debt issuance are strongly positively associated with the contemporaneous changes in returns on assets and on equity as well as with earnings surprises. This may account for the finding that debt issuance forecasts negative abnormal returns, since debt issuance also forecasts negative changes in returns on assets and on equity and negative earnings surprises. Different mechanisms appear to be at work for firms that retire debt
Taxation, growth and welfare: Dynamic effects of Estonia’s 2000 income tax act
This paper analyses the long-run effects of Estonia’s 2000 Income Tax Act with a dynamic general equilibrium model. Specifically, we consider the impact of the shift from an imputation system to one where companies only pay taxes on distributed profits. Balanced growth paths, transitional dynamics and welfare costs are computed. Our results indicate that the 2000 Income Tax Act leads to higher per capita income and investment, but lower welfare. A sensitivity analysis shows the results are rather robust.growth; welfare; taxation; tax reform; Estonia
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