1,442 research outputs found
Intonation in unaccompanied singing: Accuracy, drift, and a model of reference pitch memory
Copyright 2014 Acoustical Society of America. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the Acoustical Society of America.
The following article appeared in J. Acoust. Soc. Am. 136, 401 (2014) and may be found at http://dx.doi.org/10.1121/1.4881915
Time varying solar cycle protons program manual
Proton variations in earth radiation belt due to solar cycle - calculation program
Clastic Sedimentology of the Beaufort Formation, Prince Patrick Island, Canadian Arctic Islands: Late Tertiary Sandy Braided River Deposits With Woody Detritus Beds
The Beaufort Formation (probably of Pliocene age) exposed on Prince Patrick Island in the western Canadian Arctic Islands is an unlithified and poorly exposed unit consisting of the following assemblage of facies; (A) clast-supported gravel (channel floor lags, longitudinal bars); (B) cross-bedded sand (transverse bars, channel floor dunes); (C) rippled sand; (D) horizontally laminated fines - mixed sand, silt and woody detritus; (E) clay-rich mud (overbank suspension deposits); and (F) woody plant detritus, beds of flat-lying logs, sticks, twigs, wood chips, bark, leaves, needles, seeds, and moss (overbank suspension and traction deposits). Minor facies include pebble bands, plane laminated sand, and a thin bouldery basal gravel horizon. The sediments are interpreted to be sandy braided river deposits that are notable for their regionally abundant beds of course woody detritus, a feature uncommon in most ancient braided fluvial deposits. Facies A to C represent bar and channel deposits, with Facies B the most abundant. Facies C to F are relatively minor and are interpreted as low-stage overbank deposits such as abandoned channel fills. Rapid, small-scale lateral facies changes are the norm. Well-defined fining-upward sequences 1.2-2.5 m thick are uncommon. The relative rarity, thinness, and lateral impersistence of overbank facies compared to bar-channel facies suggests that significant amounts of meandering river deposits are not present. The common allochthonous woody fossils were sourced from boreal forests nearby. A thin horizon in one stratigraphic section contains tidal bundles with slack water mud drapes. The Beaufort sediments exposed on Prince Patrick Island appear to be the most proximal portion of a northwest-(offshore-) thickening clastic sheet. The eroded upper surface of the Beaufort Formation, of regional extent on the western arctic coastal plain, is covered with a highly polymict gravel lag that is far coarser and compositionally more diverse than gravel within the Beaufort Formation. Beaufort clasts and younger gravels (former glacial deposits?) appear to have been mixed together to form this residual lag, which at one site has been reworked into (glacio-?) fluvial gravel and sand filling a paleovalley.Key words: Beaufort Formation, Prince Patrick Island, sandy braided river deposits, allochthonous plant fossils, supra-Beaufort polymict lagMots clés: formation de Beaufort, île Prince Patrick, dépôtssa bleux de riviere anastomosée, fossiles végétaux allochtones, résidu polymictique déposé au-dessus de la formation de Beaufor
Estimating water flow through a hillslope using the massively parallel processor
A new two-dimensional model of water flow in a hillslope has been implemented on the Massively Parallel Processor at the Goddard Space Flight Center. Flow in the soil both in the saturated and unsaturated zones, evaporation and overland flow are all modelled, and the rainfall rates are allowed to vary spatially. Previous models of this type had always been very limited computationally. This model takes less than a minute to model all the components of the hillslope water flow for a day. The model can now be used in sensitivity studies to specify which measurements should be taken and how accurate they should be to describe such flows for environmental studies
Programming a hillslope water movement model on the MPP
A physically based numerical model was developed of heat and moisture flow within a hillslope on a parallel architecture computer, as a precursor to a model of a complete catchment. Moisture flow within a catchment includes evaporation, overland flow, flow in unsaturated soil, and flow in saturated soil. Because of the empirical evidence that moisture flow in unsaturated soil is mainly in the vertical direction, flow in the unsaturated zone can be modeled as a series of one dimensional columns. This initial version of the hillslope model includes evaporation and a single column of one dimensional unsaturated zone flow. This case has already been solved on an IBM 3081 computer and is now being applied to the massively parallel processor architecture so as to make the extension to the one dimensional case easier and to check the problems and benefits of using a parallel architecture machine
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Transaction based indices for the UK commercial real estate market: an exploration using IPD transaction data
The nature of private commercial real estate markets presents difficulties for monitoring market performance. Assets are heterogeneous and spatially dispersed, trading is infrequent and there is no central marketplace in which prices and cash flows of properties can be easily observed. Appraisal based indices represent one response to these issues. However, these have been criticised on a number of grounds: that they may understate volatility, lag turning points and be affected by client influence issues. Thus, this paper reports econometrically derived transaction based indices of the UK commercial real estate market using Investment Property Databank (IPD) data, comparing them with published appraisal based indices. The method is similar to that presented by Fisher, Geltner, and Pollakowski (2007) and used by Massachusett, Institute of Technology (MIT) on National Council of Real Estate Investment Fiduciaries (NCREIF) data, although it employs value rather than equal weighting. The results show stronger growth from the transaction based indices in the run up to the peak in the UK market in 2007. They also show that returns from these series are more volatile and less autocorrelated than their appraisal based counterparts, but, surprisingly, differences in turning points were not found. The conclusion then debates the applications and limitations these series have as measures of market performance
Dynamical Phase Transitions In Driven Integrate-And-Fire Neurons
We explore the dynamics of an integrate-and-fire neuron with an oscillatory
stimulus. The frustration due to the competition between the neuron's natural
firing period and that of the oscillatory rhythm, leads to a rich structure of
asymptotic phase locking patterns and ordering dynamics. The phase transitions
between these states can be classified as either tangent or discontinuous
bifurcations, each with its own characteristic scaling laws. The discontinuous
bifurcations exhibit a new kind of phase transition that may be viewed as
intermediate between continuous and first order, while tangent bifurcations
behave like continuous transitions with a diverging coherence scale.Comment: 4 pages, 5 figure
Capture zones of the family of functions lambda z^m exp(z)
We consider the family of entire transcendental maps given by where m>=2. All functions have a
superattracting fixed point at z=0, and a critical point at z=-m. In the
dynamical plane we study the topology of the basin of attraction of z=0. In the
parameter plane we focus on the capture behaviour, i.e., \lambda values such
that the critical point belongs to the basin of attraction of z=0. In
particular, we find a capture zone for which this basin has a unique connected
component, whose boundary is then non-locally connected. However, there are
parameter values for which the boundary of the immediate basin of z=0 is a
quasicircle.Comment: 25 pages, 14 figures. Accepted for publication in the International
Journal of bifurcation and Chao
Reversible skew laurent polynomial rings and deformations of poisson automorphisms
A skew Laurent polynomial ring S = R[x(+/- 1); alpha] is reversible if it has a reversing automorphism, that is, an automorphism theta of period 2 that transposes x and x(-1) and restricts to an automorphism gamma of R with gamma = gamma(-1). We study invariants for reversing automorphisms and apply our methods to determine the rings of invariants of reversing automorphisms of the two most familiar examples of simple skew Laurent polynomial rings, namely a localization of the enveloping algebra of the two-dimensional non-abelian solvable Lie algebra and the coordinate ring of the quantum torus, both of which are deformations of Poisson algebras over the base field F. Their reversing automorphisms are deformations of Poisson automorphisms of those Poisson algebras. In each case, the ring of invariants of the Poisson automorphism is the coordinate ring B of a surface in F-3 and the ring of invariants S-theta of the reversing automorphism is a deformation of B and is a factor of a deformation of F[x(1), x(2), x(3)] for a Poisson bracket determined by the appropriate surface
Truncated states obtained by iteration
Quantum states of the electromagnetic field are of considerable importance,
finding potential application in various areas of physics, as diverse as solid
state physics, quantum communication and cosmology. In this paper we introduce
the concept of truncated states obtained via iterative processes (TSI) and
study its statistical features, making an analogy with dynamical systems theory
(DST). As a specific example, we have studied TSI for the doubling and the
logistic functions, which are standard functions in studying chaos. TSI for
both the doubling and logistic functions exhibit certain similar patterns when
their statistical features are compared from the point of view of DST. A
general method to engineer TSI in the running-wave domain is employed, which
includes the errors due to the nonidealities of detectors and photocounts.Comment: 10 pages, 22 figure
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