23,476 research outputs found
Long Range Scattering and Modified Wave Operators for some Hartree Type Equations
We study the theory of scattering for a class of Hartree type equations with
long range interactions in space dimension n > 2, including Hartree equations
with potential V(x) = lambda |x|^{- gamma} with gamma < 1. For 1/2 < gamma < 1
we prove the existence of modified wave operators with no size restriction on
the data and we determine the asymptotic behaviour in time of solutions in the
range of the wave operators.Comment: TeX, 89 pages, available http://qcd.th.u-psud.f
Group theoretical study of LOCC-detection of maximally entangled state using hypothesis testing
In the asymptotic setting, the optimal test for hypotheses testing of the
maximally entangled state is derived under several locality conditions for
measurements. The optimal test is obtained in several cases with the asymptotic
framework as well as the finite-sample framework. In addition, the experimental
scheme for the optimal test is presented
Competition and credit and debit card interchange fees: a cross-country analysis
This paper seeks to provide a bridge between the theoretical and empirical literatures on interchange fees. Specifically, the paper confronts theory with practice by asking, to what extent do existing models of interchange fees match up with actual interchange fee practices in various countries? For each of four countries—Australia, the Netherlands, the UK, and the United States—models that “best” fit the competitive and institutional features of that country’s payment card market are identified, and the implications of those model are compared to actual practices. Along what competitive dimensions is there alignment? Along what competitive dimensions is there not alignment? What country-specific factors appear to be important in explaining deviations from theoretical predictions? The results suggest that a theory applicable in one country may not be applicable in another, and that similar interchange fee arrangements and regulations may well have different implications in different countries.Credit cards ; Debit cards ; Competition
Interchange fees in Australia, the UK, and the United States : matching theory and practice
Interchange fees are an integral part of the pricing structure of credit and debit card industries. While in recent years the theoretical literature on interchange fees, and payment cards in general, has grown rapidly, the empirical literature has not. There are several reasons for this. First, comprehensive data are hard to obtain. Second, the industries are very complicated, and empirical models need to incorporate many industry-specific features, such as payment-card network rules and government regulations. And third, empirical studies may require a generalized empirical model since, typically, only a few payment card networks exist in a given country. However, because of the first and second reasons, generalizing empirical models may prove problematic. ; Hayashi and Weiner seek to provide a bridge between the theoretical and empirical literatures on interchange fees. Specifically, they confront theory with practice by asking, to what extent do existing models of interchange fees match up with actual interchange fee practices in various countries? For each of three key countries—Australia, the United Kingdom, and the United States—models that “best” fit the competitive and institutional features of that country’s payment card market are identified, and the implications of those models are compared to actual practices. Along what competitive dimensions is there alignment? Along what competitive dimensions is there not alignment? What country-specific factors appear to be important in explaining deviations from theoretical predictions? The results suggest that a theory applicable in one country may not be applicable in another and that similar interchange fee arrangements and regulations may well have different implications in different countries.Credit cards ; Debit cards
Back-in-time dynamics of the cluster IE 0657-56 (the Bullet System)
We present a simplified dynamical model of the ``Bullet'' system of two
colliding clusters. The model constrains the masses of the system by requiring
that the orbits of the main and sub components satisfy the cosmological initial
conditions of vanishing physical separation a Hubble time ago. This is also
known as the timing argument. The model considers a system embedded in an
over-dense region. We argue that a relative speed of between
the two components is consistent with cosmological conditions if the system is
of a total mass of is embedded in a region of
a (mild) over-density of 10 times the cosmological background density.
Combining this with the lensing measurements of the projected mass, the model
yields a ratio of 3:1 for the mass of the main relative to that of the
subcomponent. The effect of the background weakens as the relative speed
between the two components is decreased. For relative speeds lower than , the timing argument yields masses which are too low to be
consistent with lensing.Comment: 5 pages, 3 figures, submitted to MNRA
A guide to the ATM and debit card industry - 2006 update
It has been three years since we published A Guide to the ATM and Debit Card Industry. Those three years represent a very dynamic time in the industry with a number of important developments. Some trends and patterns have persisted or accelerated, while others have peaked or reversed. Still others have emerged for the first time. The purpose of this 2006 Update is to document these trends and patterns by updating the data we presented in the original book and to discuss their implications for the current and future state of the industry. ; The most important development is that the two segments of the industry, ATM and debit, are in some sense going in opposite directions. The ATM industry has matured and is relatively stagnant, with major players jockeying for position, searching for and adopting different business strategies, and adjusting to the maturation of the industry. The debit card industry, in contrast, is expanding rapidly, with new players, new partnerships, new products, and new markets. The challenge in the debit card industry is not how to cope with a maturing industry but, rather, how to preserve and enhance position and not be left behind. ; In the first part of this Update, we highlight and discuss some of the most important changes in the ATM and debit card industry. For both the ATM and debit sides of the industry, we recap and analyze changes in activity levels, industry structure, and industry pricing. We then offer some thoughts on what might lie ahead, including a discussion of fraud and data security. In the second part of this Update, we present updated versions of the 23 charts and 11 tables from the original book, adding the three or four years of additional data that have since become available.Automated tellers ; Debit cards ; Point-of-sale-systems ; Payment systems
Nuclear Magnetic Relaxation Rate in a Noncentrosymmetric Superconductor
For a noncentrosymmetric superconductor such as CePt3Si, we consider a Cooper
pairing model with a two-component order parameter composed of spin-singlet and
spin-triplet pairing components.
We demonstrate that such a model on a qualitative level accounts for
experimentally observed features of the temperature dependence of the nuclear
spin-lattice relaxation rate 1/T1, namely a peak just below Tc and a line-node
gap behavior at low temperatures.Comment: 4 page
Ancient properties of spider silks revealed by the complete gene sequence of the prey-wrapping silk protein (AcSp1).
Spider silk fibers have impressive mechanical properties and are primarily composed of highly repetitive structural proteins (termed spidroins) encoded by a single gene family. Most characterized spidroin genes are incompletely known because of their extreme size (typically >9 kb) and repetitiveness, limiting understanding of the evolutionary processes that gave rise to their unusual gene architectures. The only complete spidroin genes characterized thus far form the dragline in the Western black widow, Latrodectus hesperus. Here, we describe the first complete gene sequence encoding the aciniform spidroin AcSp1, the primary component of spider prey-wrapping fibers. L. hesperus AcSp1 contains a single enormous (∼19 kb) exon. The AcSp1 repeat sequence is exceptionally conserved between two widow species (∼94% identity) and between widows and distantly related orb-weavers (∼30% identity), consistent with a history of strong purifying selection on its amino acid sequence. Furthermore, the 16 repeats (each 371-375 amino acids long) found in black widow AcSp1 are, on average, >99% identical at the nucleotide level. A combination of stabilizing selection on amino acid sequence, selection on silent sites, and intragenic recombination likely explains the extreme homogenization of AcSp1 repeats. In addition, phylogenetic analyses of spidroin paralogs support a gene duplication event occurring concomitantly with specialization of the aciniform glands and the tubuliform glands, which synthesize egg-case silk. With repeats that are dramatically different in length and amino acid composition from dragline spidroins, our L. hesperus AcSp1 expands the knowledge base for developing silk-based biomimetic technologies
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