137 research outputs found
Probability of informed trading on the euro overnight market rate: an update
In this paper the probability of informed trading (PIN) model developed by Easley and O’Hara (1992) is applied to analyze the role and impact of heterogeneities in euro overnight unsecured market. The empirical assessment of the functioning of this market is based on the PIN which measures the ability of traders to interpret signals on the expected evolution of the overnight rate. Results show that between 2000 and 2004 a heterogeneous learning process of market mechanisms within participants could be observed, whereas such asymmetries have been sharply decreasing since 2005. This is reviewed against some significant events that occurred in the euro money market, such as the reform of the Eurosystem’s operational framework in March 2004 and the recent financial market turmoil, which has represented a break in the steady decline of asymmetries as evidence suggest. JEL Classification: G14, E52Microstructure, money markets, PIN model
On Newton-Cartan trace anomalies
We classify the trace anomaly for parity-invariant non-relativistic
Schr\"odinger theories in 2+1 dimensions coupled to background Newton-Cartan
gravity. The general anomaly structure looks very different from the one in the
z=2 Lifshitz theories. The type A content of the anomaly is remarkably
identical to that of the relativistic 3+1 dimensional case, suggesting the
conjecture that an a-theorem should exist also in the Newton-Cartan context.
Erratum: due to an overcounting of the number of linearly-independent terms
in the basis, the type A anomaly disappears if Frobenius condition is imposed.
See appended erratum for details. This crucial mistake was pointed out to us in
arXiv:1601.06795.Comment: 16 pages, V2:few equations corrected (final results unchanged),
references added, typos, V3: erratum include
Trace anomaly for non-relativistic fermions
We study the coupling of a 2+1 dimensional non-relativistic spin 1/2 fermion
to a curved Newton-Cartan geometry, using null reduction from an
extra-dimensional relativistic Dirac action in curved spacetime. We analyze
Weyl invariance in detail: we show that at the classical level it is preserved
in an arbitrary curved background, whereas at the quantum level it is broken by
anomalies. We compute the trace anomaly using the Heat Kernel method and we
show that the anomaly coefficients a, c are proportional to the relativistic
ones for a Dirac fermion in 3+1 dimensions. As for the previously studied
scalar case, these coefficents are proportional to 1/m, where m is the
non-relativistic mass of the particle.Comment: 23 page
Nonrelativistic trace and diffeomorphism anomalies in particle number background
Using the heat kernel method, we compute nonrelativistic trace anomalies for
Schr\"odinger theories in flat spacetime, with a generic background gauge field
for the particle number symmetry, both for a free scalar and a free fermion.
The result is genuinely nonrelativistic, and it has no counterpart in the
relativistic case. Contrary to the naive expectations, the anomaly is not
gauge-invariant; this is similar to the non-gauge covariance of the non-abelian
relativistic anomaly. We also show that, in the same background, the
gravitational anomaly for a nonrelativistic scalar vanishes.Comment: 20 pages; V2 minor changes also in title, typo
Renormalization properties of a Galilean Wess-Zumino model
We consider a Galilean N=2 supersymmetric theory in 2+1 dimensions with
F-term couplings, obtained by null reduction of a relativistic Wess-Zumino
model. We compute quantum corrections and we check that, as for the
relativistic parent theory, the F-term does not receive quantum corrections.
Even more, we find evidence that the causal structure of the non-relativistic
dynamics together with particle number conservation constrain the theory to be
one-loop exact.Comment: 41 pages, 21 figures; v2: references adde
Volume and complexity for warped AdS black holes
We study the Complexity=Volume conjecture for Warped AdS black holes. We
compute the spatial volume of the Einstein-Rosen bridge and we find that its
growth rate is proportional to the Hawking temperature times the
Bekenstein-Hawking entropy. This is consistent with expectations about
computational complexity in the boundary theory.Comment: 18 pages, 3 figures, V2: refs adde
A RESTful API for exchanging Materials Data in the AFLOWLIB.org consortium
The continued advancement of science depends on shared and reproducible data.
In the field of computational materials science and rational materials design
this entails the construction of large open databases of materials properties.
To this end, an Application Program Interface (API) following REST principles
is introduced for the AFLOWLIB.org materials data repositories consortium.
AUIDs (Aflowlib Unique IDentifier) and AURLs (Aflowlib Uniform Resource
locator) are assigned to the database resources according to a well-defined
protocol described herein, which enables the client to access, through
appropriate queries, the desired data for post-processing. This introduces a
new level of openness into the AFLOWLIB repository, allowing the community to
construct high-level work-flows and tools exploiting its rich data set of
calculated structural, thermodynamic, and electronic properties. Furthermore,
federating these tools would open the door to collaborative investigation of
the data by an unprecedented extended community of users to accelerate the
advancement of computational materials design and development.Comment: 22 pages, 7 figure
A New ELISA Using the ANANAS Technology Showing High Sensitivity to diagnose the Bovine Rhinotracheitis from Individual Sera to Pooled Milk
Diagnostic tests for veterinary surveillance programs should be efficient, easy to use and, possibly, economical. In this context, classic Enzyme linked ImmunoSorbent Assay (ELISA) remains the most common analytical platform employed for serological analyses. The analysis of pooled samples instead of individual ones is a common procedure that permits to certify, with one single test, entire herds as "disease-free". However, diagnostic tests for pooled samples need to be particularly sensitive, especially when the levels of disease markers are low, as in the case of anti-BoHV1 antibodies in milk as markers of Infectious Bovine Rhinotracheitis (IBR) disease. The avidin-nucleic-acid-nanoassembly (ANANAS) is a novel kind of signal amplification platform for immunodiagnostics based on colloidal poly-avidin nanoparticles that, using model analytes, was shown to strongly increase ELISA test performance as compared to monomeric avidin. Here, for the first time, we applied the ANANAS reagent integration in a real diagnostic context. The monoclonal 1G10 anti-bovine IgG1 antibody was biotinylated and integrated with the ANANAS reagents for indirect IBR diagnosis from pooled milk mimicking tank samples from herds with IBR prevalence between 1 to 8%. The sensitivity and specificity of the ANANAS integrated method was compared to that of a classic test based on the same 1G10 antibody directly linked to horseradish peroxidase, and a commercial IDEXX kit recently introduced in the market. ANANAS integration increased by 5-fold the sensitivity of the 1G10 mAb-based conventional ELISA without loosing specificity. When compared to the commercial kit, the 1G10-ANANAS integrated method was capable to detect the presence of anti-BHV1 antibodies from bulk milk of gE antibody positive animals with 2-fold higher sensitivity and similar specificity. The results demonstrate the potentials of this new amplification technology, which permits improving current classic ELISA sensitivity limits without the need for new hardware investments
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