2,174 research outputs found
The composition of capital inflows when emerging market firms face financing constraints
The composition of capital inflows to emerging market economies tends to follow a predictable dynamic pattern across the business cycle. In most emerging market economies, total inflows are procyclical, with debt and portfolio equity flowing in first, followed later in the expansion by foreign direct investment (FDI). To understand the timing of these flows, we use a small open economy (SOE) framework to model the composition of capital inflows as the equilibrium outcome of emerging market firms' financing decisions. We show how costly external financing and foreign direct investment search costs generate a state contingent cost of financing, so that the "cheapest" source of financing depends on the phase of the business cycle. In this manner, the financial frictions are able to explain the interaction between the types of flows and deliver a time varying composition of flows, as well as other standard features of emerging market business cycles. If, as this work suggests, flows are an equilibrium outcome of firms' financing decisions then volatility of capital inflows is not necessarily "bad" for an economy. Furthermore, using capital controls to shut down one type of flow and encourage another is certain to have both long- and short-run welfare implications.Capital movements ; Emerging markets
Spatial expansions and travelling waves of rabies in vampire bats
A major obstacle to anticipating the cross-species transmission of zoonotic diseases and developing novel strategies for their control is the scarcity of data informing how these pathogens circulate within natural reservoir populations. Vampire bats are the primary reservoir of rabies in Latin America, where the disease remains among the most important viral zoonoses affecting humans and livestock. Unpredictable spatiotemporal dynamics of rabies within bat populations have precluded anticipation of outbreaks and undermined widespread bat culling programs. By analysing 1146 vampire bat-transmitted rabies (VBR) outbreaks in livestock across 12 years in Peru, we demonstrate that viral expansions into historically uninfected zones have doubled the recent burden of VBR. Viral expansions are geographically widespread, but severely constrained by high elevation peaks in the Andes mountains. Within Andean valleys, invasions form wavefronts that are advancing towards large, unvaccinated livestock populations that are heavily bitten by bats, which together will fuel high transmission and mortality. Using spatial models, we forecast the pathways of ongoing VBR epizootics across heterogeneous landscapes. These results directly inform vaccination strategies to mitigate impending viral emergence, reveal VBR as an emerging rather than an enzootic disease and create opportunities to test novel interventions to manage viruses in bat reservoirs
The impact of income adjustments in the Casen Survey on the measurement of inequality in Chile
The adjustment of the information obtained from household surveys to make the figures compatible with National Accounts is a non-standard and potentially questionable practice given that it alters the structure of income distribution. This paper analyzes the sensitivity of inequality and poverty indicators to the adjustments made by ECLAC so as to enable a consistency between what is reported by the CASEN survey and the National Accounts figures in Chile. The results reveal that this leads to important changes in the top-end of the distribution and to an overestimation in the main inequality indicators in Chile. Chile looks more unequal in international relative terms due to this adjustment.Inequality, Poverty, Income adjustment, Chile
Power Counting and Perturbative One Pion Exchange in Heavy Meson Molecules
We discuss the possible power counting schemes that can be applied in the
effective field theory description of heavy meson molecules, such as the
X(3872) or the recently discovered Zb(10610) and Zb(10650) states. We argue
that the effect of coupled channels is suppressed by at least two orders in the
effective field theory expansion, meaning that they can be safely ignored at
lowest order. The role of the one pion exchange potential between the heavy
mesons, and in particular the tensor force, is also analyzed. By using
techniques developed in atomic physics for handling power-law singular
potentials, which have been also successfully employed in nuclear physics, we
determine the range of center-of-mass momenta for which the tensor piece of the
one pion exchange potential is perturbative. In this momentum range, the one
pion exchange potential can be considered a subleading order correction,
leaving at lowest order a very simple effective field theory consisting only on
contact-range interactions.Comment: 21 pages, 1 figur
Long-distance structure of the X(3872)
We investigate heavy quark symmetries for heavy meson hadronic molecules, and
explore the consequences of assuming the X(3872) and as an
isoscalar and an isovector hadronic molecules,
respectively. The symmetry allows to predict new hadronic molecules, in
particular we find an isoscalar bound state with a mass
about 10580 MeV and the isovector charmonium partners of the and
the states. Next, we study the
three body decay. This decay mode is more sensitive to the long-distance
structure of the X(3872) resonance than its and
decays, which are mainly controlled by the short distance part of the X(3872)
molecular wave function. We discuss the final state
interactions, which in some situations become quite important. Indeed in these
cases, a precise measurement of this partial decay width could provide precise
information on the interaction strength between the charm
mesons.Comment: Talk presented at the "XI International Conference on Hyperons, Charm
and Beauty Hadrons (BEACH 2014)", Birmingham (U.K.), July 201
The Heavy Quark Spin Symmetry Partners of the X(3872)
We explore the consequences of heavy quark spin symmetry for the charmed
meson-antimeson system in a contact-range (or pionless) effective field theory.
As a trivial consequence, we theorize the existence of a heavy quark spin
symmetry partner of the X(3872), with , which we call X(4012) in
reference to its predicted mass. If we additionally assume that the X(3915) is
a heavy spin symmetry partner of the X(3872), we end up predicting a
total of six molecular states. We also discuss the error
induced by higher order effects such as finite heavy quark mass corrections,
pion exchanges and coupled channels, allowing us to estimate the expected
theoretical uncertainties in the position of these new states.Comment: 18 pages; final version accepted for publicatio
System-adapted correlation energy density functionals from effective pair interactions
We present and discuss some ideas concerning an ``average-pair-density
functional theory'', in which the ground-state energy of a many-electron system
is rewritten as a functional of the spherically and system-averaged pair
density. These ideas are further clarified with simple physical examples. We
then show that the proposed formalism can be combined with density functional
theory to build system-adapted correlation energy functionals. A simple
approximation for the unknown effective electron-electron interaction that
enters in this combined approach is described, and results for the He series
and for the uniform electron gas are briefly reviewed.Comment: to appear in Phil. Mag. as part of Conference proceedings for the
"Electron Correlations and Materials Properties", Kos Greece, July 5-9, 200
Gauge invariance in the presence of a cutoff
We use the method of gauging equations to construct the electromagnetic
current operator for the two-nucleon system in a theory with a finite cutoff.
The employed formulation ensures that the two-nucleon T-matrix and
corresponding five-point function, in the cutoff theory, are identical to the
ones formally defined by a reference theory without a cutoff. A feature of our
approach is that it effectively introduces a cutoff into the reference theory
in a way that maintains the long-range part of the exchange current operator;
for applications to effective field theory (EFT), this property is usually
sufficient to guarantee the predictive power of the resulting cutoff theory. In
addition, our approach leads to Ward-Takahashi (WT) identities that are linear
in the interactions.
From the point of view of EFT's where such a WT identity is satisfied in the
reference theory, this ensures that gauge invariance in the cutoff theory is
maintained order by order in the expansion.Comment: 15 pages, 2 figure
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