2,507 research outputs found
Panama's growth diagnostics
"In this context, the objective of the paper is to propose a set of recommendations on whatneeds to be done in order to assure success of the current growth strategy. We have nodoubts on the value of strengthening Panama´s geographical comparative advantage withthe Canal´s expansion. The key question is to identify the additional steps which could promote growth in the non-canal economy. In addition to making growth more sustainable,growth acceleration in the traditional sectors can result in a reduction of inequality, whichis extremely high in Panama.To answer these questions the paper proceeds in the following way. Section 2 discussessome key features of Panama´s economic structure that are important for the analysis.Section 3 analyzes Panama´s growth using conventional techniques. In particular, we lookat the role of the `fundamental´ determinants of growth, such as institutions, geography,and human capital. Also, the time series analysis shows that growth has experiencedreversals while a standard sources-of-growth decomposition suggests that Panama has asevere productivity problem. Sections 4 to 8 deal with the GDM. Section 4 presents somegeneral evidence from the Investment Climate Survey (ICS) on the main concerns ofPanama´s entrepreneurs. Section 5 discusses all the problems that could imply low socialreturns to investment. Section 6 analyzes the issues related to problems of appropriability.Section 7 introduces the problems of self-discovery, and Section 8 looks at financingissues. Section 9 concludes"Crecimiento Económico, Panamá
Non-Markovian qubit dynamics in a circuit-QED setup
We consider a circuit-QED setup that allows the induction and control of
non-Markovian dynamics of a qubit. Non-Markovianity is enforced over the qubit
by means of its direct coupling to a bosonic mode which is controllably coupled
to other qubit-mode system. We show that this configuration can be achieved in
a circuit-QED setup consisting of two initially independent superconducting
circuits, each formed by one charge qubit and one transmission-line resonator,
which are put in interaction by coupling the resonators to a current-biased
Josephson junction. We solve this problem exactly and then proceed with a
thorough investigation of the emergent non-Markovianity in the dynamics of the
qubits. Our study might serve the context for a first experimental assessment
of non-Markovianity in a multi-element solid-state device.Comment: 8 pages, 7 figures, slightly changed titl
Contact forces distribution for a granular material from a Monte Carlo study on a single grain
The force network ensemble is one of the most promising statistical
descriptions of granular media, with an entropy accounting for all force
configurations at mechanical equilibrium consistent with some external stress.
It is possible to define a temperature-like parameter, the angoricity
{\alpha}^{-1}, which under isotropic compression is a scalar variable. This
ensemble is frequently studied on whole packings of grains; however, previous
works have shown that spatial correlations can be neglected in many cases,
opening the door to studies on a single grain. Our work develops a Monte Carlo
method to sample the force ensemble on a single grain at constant angoricity on
two and three-dimensional mono-disperse granular systems, both with or without
static friction. The results show that, despite the steric exclusions and the
constrictions of Coulomb's limit and repulsive normal forces, the pressure per
grain always show a gamma distribution with scale parameter {\nu} =
{\alpha}^{-1} and shape parameter k close to k', the number of degrees of
freedom in the system. Moreover, the average pressure per grain fulfills an
equipartition theorem =k'{\alpha}^{-1} in all cases (in close parallelism
with the one for an ideal gas). These results suggest the existence of k'
independent random variables (i.e. elementary forces) with identical
exponential distributions as the basic elements for describing the force
network ensemble at low angoricities under isotropic compression, in analogy
with the volume ensemble of granular materials
Degree of Quantumness in Quantum Synchronization
We introduce the concept of degree of quantumness in quantum synchronization,
a measure of the quantum nature of synchronization in quantum systems.
Following techniques from quantum information, we propose the number of
non-commuting observables that synchronize as a measure of quantumness. This
figure of merit is compatible with already existing synchronization
measurements, and it captures different physical properties. We illustrate it
in a quantum system consisting of two weakly interacting cavity-qubit systems,
which are coupled via the exchange of bosonic excitations between the cavities.
Moreover, we study the synchronization of the expectation values of the Pauli
operators and we propose a feasible superconducting circuit setup. Finally, we
discuss the degree of quantumness in the synchronization between two quantum
van der Pol oscillators
The Development of Colombian Bond Market.
Abstract: In this paper we explore the determinants and the consequences of the development of the corporate bond market in Colombia. We use a large firm-level dataset for the period 1997-2004 and find that the larger, more profitable and more leveraged firms have a higher probability to issue bonds. The econometric results also show that the larger the treasury bond market, the lower the probability that a firm will issue bonds, suggesting the presenceof a crowding out effect. On the demand side, the panel estimations indicate that investors with larger portfolios tend to hold more corporate bonds. Also, from the viewpoint of investors, average bond issue size is a critical variable. Finally, we find that sectors that have more corporate bonds (as percentage of total liabilities) have greater loan quality, and this result is stronger during periods of banking crises. We conclude that bond market development can play an important countercyclical role during periods of financial stress.Resumen: En este trabajo exploramos los determinantes y las consecuencias del desarrollo del mercado de bonos corporativos en Colombia. Utilizamos una muestra amplia con informaciĂłn por firma para el perĂodo 1997-2004 y encontramos que las firmas más grandes, rentables y apalancadas tienen una mayor probabilidad de emitir bonos. Los resultados economĂ©tricos tambiĂ©n muestran que un mayor tamaño del mercado de deuda pĂşblica tiene un efecto negativo sobre la probabilidad de las firmas de emitir bonos, lo cual sugiere un efecto de crowding out. Por el lado de la demanda, las estimaciones de panel indican que los inversionistas con portafolios grandes tienen mayor probabilidad de adquirir bonos. AsĂ mismo, desde el punto de vista de los inversionistas, el tamaño promedio de la emisiĂłn es una variable crĂtica. Finalmente, encontramos que los sectores econĂłmicos en donde la participaciĂłn de los bonos dentro del total de pasivos es mayor, tienen una mejor calidad de la cartera y enfrentan con mayor fortaleza los perĂodos de crisis. Concluimos que el mercado de bonos puede tener un importante papel contra cĂclico en perĂodos de stress financiero.Mercado de bonos, mercado financiero; Bonos corporativos, Inversionistas, Colombia
CRIRES-VLT high-resolution spectro-astrometry as a tool in the search of small structures at the cores of Planetary Nebulae
The onset of the asymmetry in planetary nebulae (PNe) occurs during the short
transition between the end of the asymptotic giant branch (AGB) phase and the
beginning of the PN phase. Sources in this transition phase are compact and
emit intensely in infrared wavelengths, making high spatial resolution
observations in the infrared mandatory to investigate the shaping process of
PNe. Interferometric VLTI IR observations have revealed compelling evidence of
disks at the cores of PNe, but the limited sensitivity, strong observational
constraints, and limited spatial coverage place severe limits on the universal
use of this technique. Inspired by the successful detection of proto-planetary
disks using spectro-astrometric observations, we apply here for the first time
this technique to search for sub-arcsecond structures in PNe. Our exploratory
study using CRIRES (CRyogenic high-resolution Infra-Red Echelle Spectrograph)
commissioning data of the proto-PN IRAS 17516-2525 and the young PN SwSt 1 has
revealed small-sized structures after the spectro-astrometric analysis of the
two sources. In IRAS 17516-2525, the spectro-astrometric signal has a size of
only 12 mas, as detected in the Brackett-gamma line, whereas the structures
found in SwSt 1 have sizes of 230 mas in the [Fe III] line and 130 mas in the
Brackett-gamma line. The spectroscopic observations required to perform
spectro-astrometry of sources in the transition towards the PN phase are less
time consuming and much more sensitive than VLTI IR observations. The results
presented here open a new window in the search of the small-sized collimating
agents that shape the complex morphologies of extremely axisymmetric PNe.Comment: 6 pages, 4 figure
Weak -structures and one-relator groups
Motivated by the notion of boundary for hyperbolic and groups, M.
Bestvina in "Local Homology Properties of Boundaries of Groups" introduced the
notion of a (weak) -structure and (weak) -boundary for
a group of type (i.e., having a finite complex), with
implications concerning the Novikov conjecture for . Since then, some
classes of groups have been shown to admit a weak -structure (see
"Weak -structures for some classes of groups" by C.R. Guilbault for
example), but the question whether or not every group of type
admits such a structure remains open. In this paper, we show that every torsion
free one-relator group admits a weak -structure, by showing that
they are all properly aspherical at infinity; moreover, in the -ended case
the corresponding weak -boundary has the shape of either a circle
or a Hawaiian earring depending on whether the group is a virtually surface
group or not. Finally, we extend this result to a wider class of groups still
satisfying a Freiheitssatz property
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