5,848 research outputs found
Greenberger-Horne-Zeilinger state generation with linear optical elements
We propose a scheme to probabilistically generate Greenberger-Horne-Zeilinger
(GHZ) states encoded on the path degree of freedom of three photons. These
photons are totally independent from each other, having no direct interaction
during the whole evolution of the protocol, which remarkably requires only
linear optical devices to work, and two extra ancillary photons to mediate the
correlation. The efficacy of the method, which has potential application in
distribited quantum computation and multiparty quantum communication, is
analyzed in comparison with similar proposals reported in the recent
literature. We also discuss the main error sources that limit the efficiency of
the protocol in a real experiment and some interesting aspects about the
mediator photons in connection with the concept of spatial nonlocality
Ineffective Controls on Capital Inflows Under Sophisticated Financial Markets: Brazil in the Nineties
We analyze the Brazilian experience in the 1990s to assess the effectiveness of controls on capital inflows in restricting financial inflows and changing their composition towards long term flows. Econometric exercises (VARs) showed that controls on capital inflows were effective in deterring financial inflows for only a brief period, from two to six months. The hypothesis to explain the ineffectiveness of the controls is that financial institutions performed several operations aimed at avoiding capital controls. To check this hypothesis, we conducted interviews with market players. We collected several examples of the financial strategies engineered to avoid the capital controls and invest in the Brazilian fixed income market. The main conclusion is that controls on capital inflows, while they may be desirable, are of very limited effectiveness under sophisticated financial markets.
A Stochastic Broadcast Pi-Calculus
In this paper we propose a stochastic broadcast PI-calculus which can be used
to model server-client based systems where synchronization is always governed
by only one participant. Therefore, there is no need to determine the joint
synchronization rates. We also take immediate transitions into account which is
useful to model behaviors with no impact on the temporal properties of a
system. Since immediate transitions may introduce non-determinism, we will show
how these non-determinism can be resolved, and as result a valid CTMC will be
obtained finally. Also some practical examples are given to show the
application of this calculus.Comment: In Proceedings QAPL 2011, arXiv:1107.074
Distributed Discontinuous Coupling for Convergence in Heterogeneous Networks
In this letter, we propose the use of a distributed discontinuous coupling protocol to achieve convergence and synchronization in networks of non-identical nonlinear dynamical systems. We show that the synchronous dynamics is a solution to the average of the nodes' vector fields, and derive analytical estimates of the critical coupling gains required to achieve convergence
Fish-based groups for ecological assessment in rivers: the importance of environmental drivers on taxonomic and functional traits of fish Assemblages
The use of river-types is of practical value, serving as groups for which
assessment procedures can be developed and applied. An abiotic typology
was set by the Portuguese Water Agency, mainly based on 6 major
morphoclimatic regions. However, to be biologically meaningful, this typology
should fit the distribution patterns of the biological quality elements
communities proposed in Water Framework Directive under the lowest
possible human pressure. This study aimed to identify and characterize
fish-based geographical groups for continental Portugal and their environmental
and geographical discriptors, using taxonomic and functional
traits. Sampling took place between 2004 and 2006 during Spring. Fish
fauna from 155 reference sites was analysed using a multivariate
approach. Cluster Analysis on fish composition identified 10 fish-groups,
expressing a clear correspondence to the river basin level, due to the
restrict basin distribution of many species. Groups showed a wider aggregation
in 4 regions with a larger geographical correspondence, statistically
supported by Similarity Analysis, both on fish composition and mostly on
fish metrics/guilds. Principal Components Analysis revealed major environmental
drivers associated to fish-groups and fish-regions. Fish-groups
were hierarchically grouped over major and local regions, expressing a
large-scale response to a North-South environmental gradient defined by
temperature, precipitation, mineralization and altitude, and a regional scale
response mainly to drainage area and flow discharge. From North to
South, fish-regions were related to the morphoclimatic regions. Results
contributed to reduce redundance in abiotic river-types and set the final
typology for Portuguese rivers, constituting a fundamental tool for planning
and managing water resources
Integrable Generalized Thirring Model
We derive the conditions that the coupling constants of the Generalized
Thirring Model have to satisfy in order for the model to admit an infinite
number of commuting classical conserved quantities. Our treatment uses the
bosonized version of the model, with periodic boundary conditions imposed on
the space coordinate. Some explicit examples that satisfy these conditions are
discussed. We show that, with a different set of boundary conditions, there
exist additional conserved quantities, and we find the Poisson Bracket algebra
satisfied by them.Comment: Final version to be published in Nucl.Phys.B. Only minor changes. An
equation was deleted and a conclusion revised, and a few comments were added.
Harvmac, 15 pages. Full postscript available from
http://theor1.lbl.gov/www/theorgroup/papers/39040.p
A 22-Week-Old Fetus with Nager Syndrome and Congenital Diaphragmatic Hernia due to a Novel SF3B4 Mutation.
Nager syndrome, or acrofacial dysostosis type 1 (AFD1), is a rare multiple malformation syndrome characterized by hypoplasia of first and second branchial arches derivatives and appendicular anomalies with variable involvement of the radial/axial ray. In 2012, AFD1 has been associated with dominant mutations in SF3B4. We report a 22-week-old fetus with AFD1 associated with diaphragmatic hernia due to a previously unreported SF3B4 mutation (c.35-2A>G). Defective diaphragmatic development is a rare manifestation in AFD1 as it is described in only 2 previous cases, with molecular confirmation in 1 of them. Our molecular finding adds a novel pathogenic splicing variant to the SF3B4 mutational spectrum and contributes to defining its prenatal/fetal phenotype
Truncation of long-range percolation model with square non-summable interactions
We consider some problems related to the truncation question in long-range
percolation. It is given probabilities that certain long-range oriented bonds
are open; assuming that this probabilities are not summable, we ask if the
probability of percolation is positive when we truncate the graph, disallowing
bonds of range above a possibly large but finite threshold. This question is
still open if the set of vertices is . We give some conditions in which
the answer is affirmative. One of these results generalize the previous result
in [Alves, Hil\'ario, de Lima, Valesin, Journ. Stat. Phys. {\bf 122}, 972
(2017)]
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