3,635 research outputs found
Public Goods in Trade: On the Formation of Markets and Political Jurisdictions
The current debate in Western Europe centers on the relationship between economic and political integration. To address this problem, we construct a simple general equilibrium model in which the returns to trading are directly affected by the availability of a public good. In our model, heterogeneous agents choose both a club and a market to belong to. In the club, agents vote over the public good, are taxed to finance this good, and receive access to it when they trade. In the market, they are randomly matched with a partner. If a match occurs between traders of different clubs, they both suffer a transactions cost. We show that, in general, the political boundaries established by the clubs can be distinct from market borders, leading to international trade between members of different clubs. Further, as the region develops, markets become wider (eventually leading to a common market) and the desire to avoid transaction costs initially leads to political unification. At still higher levels of development, however, where transaction costs are less important, traders prefer the diversity offered by multiple clubs.
Radio-loudness in black hole transients: evidence for an inclination effect
Accreting stellar-mass black holes appear to populate two branches in a
radio:X-ray luminosity plane. We have investigated the X-ray variability
properties of a large number of black hole low-mass X-ray binaries, with the
aim of unveiling the physical reasons underlying the radio-loud/radio-quiet
nature of these sources, in the context of the known accretion-ejection
connection. A reconsideration of the available radio and X-ray data from a
sample of black hole X-ray binaries confirms that being radio-quiet is the more
normal mode of behaviour for black hole binaries. In the light of this we chose
to test, once more, the hypothesis that radio loudness could be a consequence
of the inclination of the X-ray binary. We compared the slope of the
`hard-line' (an approximately linear correlation between X-ray count rate and
rms variability, visible in the hard states of active black holes), the orbital
inclination, and the radio-nature of the sources of our sample. We found that
high-inclination objects show steeper hard-lines than low-inclination objects,
and tend to display a radio-quiet nature (with the only exception of V404 Cyg),
as opposed to low-inclination objects, which appear to be radio-loud(er). While
in need of further confirmation, our results suggest that - contrary to what
has been believed for years - the radio-loud/quiet nature of black-hole low
mass X-ray binaries might be an inclination effect, rather than an intrinsic
source property. This would solve an important issue in the context of the
inflow-outflow connection, thus providing significant constraints to the models
for the launch of hard-state compact jets.Comment: 16 pages, 6 figures, accepted for pubblication on MNRA
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A Stochastic Volatility Model With Realized Measures for Option Pricing
Based on the fact that realized measures of volatility are affected by measurement errors, we introduce a new family of discrete-time stochastic volatility models having two measurement equations relating both observed returns and realized measures to the latent conditional variance. A semi-analytical option pricing framework is developed for this class of models. In addition, we provide analytical filtering and smoothing recursions for the basic specification of the model, and an effective MCMC algorithm for its richer variants. The empirical analysis shows the effectiveness of filtering and smoothing realized measures in inflating the latent volatility persistence—the crucial parameter in pricing Standard and Poor’s 500 Index options
The Effect of Historical Narratives and Flag Type
This research will examine the effect of mainstream or marginalized historical narratives and the Confederate or American flag on temporal distancing, patriotism, perception of injustice, and assimilationist national identity. We expect that participants exposed to marginalized narratives will indicate higher perceived distance, especially when exposed to the Confederate flag. We expect that participants exposed to mainstream narratives will be highest on blind patriotism, especially when exposed to the American flag. We expect that participants in the American flag marginalized narrative condition would perceive the most racism and would reject more assimilationist conceptions of national identity. For the dependent measures of patriotism, perception of injustice, and national identity, we expect to find differences within the Confederate flag condition according to the meaning participants associate with the Confederate flag. These results will help us understand how people may respond to threatening narratives, how flag exposure may impact that response, and how historical narratives or flags can be presented to increase social justice awareness
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Economic Exchange During Hyperinflation
Historical evidence indicates that hyperinflations can disrupt individuals'
normal trading patterns and impede the orderly functioning
of markets. To explore these issues, we construct a theoretical model
of hyperinflation that focuses on individuals and their process of
economic exchange. In our model buyers must carry cash while
shopping, and some transactions take place in a decentralized setting
in which buyer and seller negotiate over the terms of trade of an
indivisible good. Since buyers face the constant threat of incoming
younger (hence richer) customers, their bargaining position is weakened
by inflation, allowing sellers to extract a higher real price. However,
we show that higher inflation also reduces buyers' search,
increasing sellers' wait for customers. As a result, the volume
of transactions concluded in the decentralized sector falls. At high
enough rates of inflation, all agents suffer a welfare loss
Genome sequence of Rhizobium sullae HCNT1 isolated from Hedysarum coronarium nodules and featuring peculiar denitrification phenotypes
The genome sequence of Rhizobium sullae strain HCNT1, isolated from root nodules of the legume Hedysarum coronarium growing in wild stands in Tuscany, Italy, is described here. Unlike other R. sullae strains, this isolate features a truncated denitrification pathway lacking NO/N2O reductase activity and displaying high sensitivity to nitrite under anaerobic conditions
The appearance of a compact jet in the soft-intermediate state of 4U 1543-47
Recent advancements in the understanding of jet-disc coupling in black hole
candidate X-ray binaries (BHXBs) have provided close links between radio jet
emission and X-ray spectral and variability behaviour. In 'soft' X-ray states
the jets are suppressed, but the current picture lacks an understanding of the
X-ray features associated with the quenching or recovering of these jets. Here
we show that a brief, ~4 day infrared (IR) brightening during a predominantly
soft X-ray state of the BHXB 4U 1543-47 is contemporaneous with a strong X-ray
Type B quasi-periodic oscillation (QPO), a slight spectral hardening and an
increase in the rms variability, indicating an excursion to the
soft-intermediate state (SIMS). This IR 'flare' has a spectral index consistent
with optically thin synchrotron emission and most likely originates from the
steady, compact jet. This core jet emitting in the IR is usually only
associated with the hard state, and its appearance during the SIMS places the
'jet line' between the SIMS and the soft state in the hardness-intensity
diagram for this source. IR emission is produced in a small region of the jets
close to where they are launched (~ 0.1 light-seconds), and the timescale of
the IR flare in 4U 1543-47 is far too long to be caused by a single, discrete
ejection. We also present a summary of the evolution of the jet and X-ray
spectral/variability properties throughout the whole outburst, constraining the
jet contribution to the X-ray flux during the decay.Comment: Accepted to MNRAS. 11 pages, 6 figure
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