8,101 research outputs found
Real exchange rate dynamics in transition economies : a nonlinear analysis
We examine the behavior of the real exchange rates of nine transition economies during the 1990s. We propose an empirical model rationalized on the basis of standard economic models in the tradition of Mundell-Fleming-Dornbusch and Harrod-Balassa-Samuelson, allowing explicitly for real interest rate differentials and (implicitly) for productivity differentials to have an impact on real exchange rate equilibrium and employing nonlinear modeling techniques that are consistent with recently developed economic theories and observed regularities. Using a nonlinear multivariate generalization of the Beveridge-Nelson decomposition applied to our models, we also identify the permanent and temporary components of these real exchange rates implied by our estimates. The results have a natural interpretation and clear policy implications
Bulges or Bars from Secular Evolution?
We use high resolution collisionless -body simulations to study the
secular evolution of disk galaxies and in particular the final properties of
disks that suffer a bar and perhaps a bar-buckling instability. Although we
find that bars are not destroyed by the buckling instability, when we decompose
the radial density profiles of the secularly-evolved disks into inner S\'ersic
and outer exponential components, for favorable viewing angles, the resulting
structural parameters, scaling relations and global kinematics of the bar
components are in good agreement with those obtained for bulges of late-type
galaxies. Round bulges may require a different formation channel or
dissipational processes.Comment: Accepted to ApJL. 4 figures, 2 in color Corrected minor typos and
reference lis
Extending fairness expressibility of ECTL+: a tree-style one-pass tableau approach
Temporal logic has become essential for various areas in computer science, most notably for the specification and verification of hardware and software systems. For the specification purposes rich temporal languages are required that, in particular, can express fairness constraints. For linear-time logics which deal with fairness in the linear-time setting, one-pass and two-pass tableau methods have been developed. In the repository of the CTL-type branching-time setting, the well-known logics ECTL and ECTL^+ were developed to explicitly deal with fairness. However, due to the syntactical restrictions, these logics can only express restricted versions of fairness. The logic CTL^*, often considered as "the full branching-time logic" overcomes these restrictions on expressing fairness. However, this logic itself, is extremely challenging for the application of verification techniques, and the tableau technique, in particular. For example, there is no one-pass tableau construction for this logic, while it is known that one-pass tableau has an additional benefit enabling the formulation of dual sequent calculi that are often treated as more "natural" being more friendly for human understanding. Based on these two considerations, the following problem arises - are there logics that have richer expressiveness than ECTL^+ yet "simpler" than CTL^* for which a one-pass tableau can be developed? In this paper we give a solution to this problem. We present a tree-style one-pass tableau for a sub-logic of CTL^* that we call ECTL^#, which is more expressive than ECTL^+ allowing the formulation of a new range of fairness constraints with "until" operator. The presentation of the tableau construction is accompanied by an algorithm for constructing a systematic tableau, for any given input of admissible branching-time formulae. We prove the termination, soundness and completeness of the method. As tree-shaped one-pass tableaux are well suited for the automation and are amenable for the implementation and for the formulation of sequent calculi, our results also open a prospect of relevant developments of the automation and implementation of the tableau method for ECTL^#, and of a dual sequent calculi
Perfect state transfers by selective quantum interferences within complex spin networks
We present a method that implement directional, perfect state transfers
within a branched spin network by exploiting quantum interferences in the
time-domain. That provides a tool to isolate subsystems from a large and
complex one. Directionality is achieved by interrupting the spin-spin coupled
evolution with periods of free Zeeman evolutions, whose timing is tuned to be
commensurate with the relative phases accrued by specific spin pairs. This
leads to a resonant transfer between the chosen qubits, and to a detuning of
all remaining pathways in the network, using only global manipulations. As the
transfer is perfect when the selected pathway is mediated by 2 or 3 spins,
distant state transfers over complex networks can be achieved by successive
recouplings among specific pairs/triads of spins. These effects are illustrated
with a quantum simulator involving 13C NMR on Leucine's backbone; a six-spin
network.Comment: 5 pages, 3 figure
Unusual products of the aqueous chlorination of atenolol
The reaction
of the drug atenolol
with hypochlorite
under conditions
that simulate
wastewater
disinfection
was investigated.
The pharmaceutical
reacted in 1 h yielding
three products
that were
separated
by chromatographic
techniques
and characterized
by spectroscopic
features.
Two unusual
products
2-(4-(3-(chloro(2-chloropropan-
2-yl)amino)-2-hydroxypropoxy)
phenyl) acetamide
and 2-(4-
(3-formamido-
2-hydroxypropoxy)
phenyl) acetamide
were obtained along with 2-(4-hydroxyphenyl)
acetamide.
When the reaction
was stopped at shorter times only 2-(4-(3-amino-2-hydroxypropoxy)
phenyl) acetamide
and the dichlorinated
product
were detected. Tests performed
on the seeds of
Lactuca
sativa
show that chlorinated
products
have phytotoxic
activity
A Numerical Study of the Hierarchical Ising Model: High Temperature Versus Epsilon Expansion
We study numerically the magnetic susceptibility of the hierarchical model
with Ising spins () above the critical temperature and for two
values of the epsilon parameter. The integrations are performed exactly, using
recursive methods which exploit the symmetries of the model. Lattices with up
to sites have been used. Surprisingly, the numerical data can be fitted
very well with a simple power law of the form for the {\it whole} temperature range. The numerical values for
agree within a few percent with the values calculated with a high-temperature
expansion but show significant discrepancies with the epsilon-expansion. We
would appreciate comments about these results.Comment: 15 Pages, 12 Figures not included (hard copies available on request),
uses phyzzx.te
The formation of Jupiter by hybrid pebble-planetesimal accretion
The standard model for giant planet formation is based on the accretion of
solids by a growing planetary embryo, followed by rapid gas accretion once the
planet exceeds a so-called critical mass. The dominant size of the accreted
solids (cm-size particles named pebbles or km to hundred km-size bodies named
planetesimals) is, however, unknown. Recently, high-precision measurements of
isotopes in meteorites provided evidence for the existence of two reservoirs in
the early Solar System. These reservoirs remained separated from ~1 until ~ 3
Myr after the beginning of the Solar System's formation. This separation is
interpreted as resulting from Jupiter growing and becoming a barrier for
material transport. In this framework, Jupiter reached ~20 Earth masses within
~1 Myr and slowly grew to ~50 Earth masses in the subsequent 2 Myr before
reaching its present-day mass. The evidence that Jupiter slowed down its growth
after reaching 20 Earth masses for at least 2 Myr is puzzling because a planet
of this mass is expected to trigger fast runaway gas accretion. Here, we use
theoretical models to describe the conditions allowing for such a slow
accretion and show that Jupiter grew in three distinct phases. First, rapid
pebble accretion brought the major part of Jupiter's core mass. Second, slow
planetesimal accretion provided the energy required to hinder runaway gas
accretion during 2 Myr. Third, runaway gas accretion proceeded. Both pebbles
and planetesimals therefore have an important role in Jupiter's formation.Comment: Published in Nature Astronomy on August 27, 201
Quintessential inflation from 5D warped product spaces on a dynamical foliation
Assuming the existence of a 5D purely kinetic scalar field on the class of
warped product spaces we investigate the possibility of mimic both an
inflationary and a quintessential scenarios on 4D hypersurfaces, by
implementing a dynamical foliation on the fifth coordinate instead of a
constant one. We obtain that an induced chaotic inflationary scenario with a
geometrically induced scalar potential and an induced quasi-vacuum equation of
state on 4D dynamical hypersurfaces is possible. While on a constant foliation
the universe can be considered as matter dominated today, in a family of 4D
dynamical hypersurfaces the universe can be passing for a period of accelerated
expansion with a deceleration parameter nearly -1. This effect of the dynamical
foliation results negligible at the inflationary epoch allowing for a chaotic
scenario and becomes considerable at the present epoch allowing a
quintessential scenario.Comment: 7 pages, 1 figure Accepted for publication in Modern Physics Letters
Muscleblind-like 3 deficit results in a spectrum of age-associated pathologies observed in myotonic dystrophy.
Myotonic dystrophy type I (DM1) exhibits distinctive disease specific phenotypes and the accelerated onset of a spectrum of age-associated pathologies. In DM1, dominant effects of expanded CUG repeats result in part from the inactivation of the muscleblind-like (MBNL) proteins. To test the role of MBNL3, we deleted Mbnl3 exon 2 (Mbnl3(ΔE2)) in mice and examined the onset of age-associated diseases over 4 to 13 months of age. Accelerated onset of glucose intolerance with elevated insulin levels, cardiac systole deficits, left ventricle hypertrophy, a predictor of a later onset of heart failure and the development of subcapsular and cortical cataracts is observed in Mbnl3(ΔE2) mice. Retention of embryonic splice isoforms in adult organs, a prominent defect in DM1, is not observed in multiple RNAs including the Insulin Receptor (Insr), Cardiac Troponin T (Tnnt2), Lim Domain Binding 3 (Ldb3) RNAs in Mbnl3(ΔE2) mice. Although rare DM1-like splice errors underlying the observed phenotypes cannot be excluded, our data in conjunction with the reported absence of alternative splice errors in embryonic muscles of a similar Mbnl3(ΔE2) mouse by RNA-seq studies, suggest that mechanisms distinct from the adult retention of embryonic splice patterns may make important contributions to the onset of age-associated pathologies in DM1
THE KINEMATIC SIGNATURE OF FACE-ON PEANUT-SHAPED BULGES
We present a kinematic diagnostic for peanut-shaped bulges in nearly face-on galaxies. The face-on view provides a novel perspective on peanuts that would allow study of their relation to bars and disks in greater detail than hitherto possible. The diagnostic is based on the fact that peanut shapes are associated with a flat density distribution in the vertical direction. We show that the kinematic signature corresponding to such a distribution is a minimum in the fourth-order Gauss-Hermite moment s4. We demonstrate our method on N-body simulations of varying peanut strength, showing that strong peanuts can be recognized to inclinations i ’ 300, regardless of the strength of the bar. We also consider compound systems in which a bulge is present in the initial conditions, as may happen if bulges form at high redshift through mergers. We show that in this case, because the vertical structure of the bulge is not derived from that of the disk, the signature of a peanut in s4 is weakened. Thus the same kinematic signature of peanuts can be used to explore bulge formation mechanisms. The observational requirements for identifying peanuts with this method are challenging, but feasible
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